Morphologic Characteristics Help Explain the Gender Difference in Peak Anterior Cruciate Ligament Strain During a Simulated Pivot Landing

PubMed Central

Lipps, David B.; Oh, Youkeun K.; Ashton-Miller, James A.; Wojtys, Edward M.

2015-01-01

Background Gender differences exist in anterior cruciate ligament (ACL) cross-sectional area and lateral tibial slope. Biomechanical principles suggest that the direction of these gender differences should induce larger peak ACL strains in females under dynamic loading. Hypothesis Peak ACL relative strain during a simulated pivot landing is significantly greater in female ACLs than male ACLs. Study Design Controlled laboratory study. Methods Twenty cadaveric knees from height- and weight-matched male and female cadavers were subjected to impulsive 3-dimensional test loads of 2 times body weight in compression, flexion, and internal tibial torque starting at 15° of flexion. Load cells measured the 3-dimensional forces and moments applied to the knee, and forces in the pretensioned quadriceps, hamstring, and gastrocnemius muscle equivalents. A novel, gender-specific, nonlinear spring simulated short-range and longer range quadriceps muscle tensile stiffness. Peak relative strain in the anteromedial bundle of the ACL (AM-ACL) was measured using a differential variable reluctance transducer, while ACL cross-sectional area and lateral tibial slope were measured using magnetic resonance imaging. A repeated-measures Mann-Whitney signed-rank test was used to test the hypothesis. Results Female knees exhibited 95% greater peak AM-ACL relative strain than male knees (6.37% [22.53%] vs 3.26% [11.89%]; P = .004). Anterior cruciate ligament cross-sectional area and lateral tibial slope were significant predictors of peak AM-ACL relative strain (R2 = .59; P = .001). Conclusion Peak AM-ACL relative strain was significantly greater in female than male knees from donors of the same height and weight. This gender difference is attributed to a smaller female ACL cross-sectional area and a greater lateral tibial slope. Clinical Relevance Since female ACLs are systematically exposed to greater strain than their male counterparts, training and injury prevention programs should take this fact into consideration. PMID:21917612

Topics in electron capture by fast ions

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

Hsin, S.H.

1987-01-01

The post-collision interaction (PCI) model was applied, together with the eikonal approximation, to study the (n = 2,3) capture cross sections in p + H(ls) collisions. The results indeed improve the previous eikonal calculations for l = 0 cases, and agree quite well with present experimental data. Calculations using the strong-potential Born (SPB) approximation, with the Sil and McGuire technique, for capture into the np, nd levels are also presented. While these cross sections are smaller than cross sections for capture into the ns levels at high velocities, nevertheless the Thomas peak is clearly evident in both the absolute valuemore » m = 2, absolute value m = 1 and m = 0 magnetic substates in p + H(ls) collisions. Also calculated were corrections to the SPB using the Distorted-Wave Born formalism of Taulbjerg and Briggs. In the sense of a plane-wave Born expansion, all terms of the third Born approximation and all single switching fourth Born terms are included, but a peaking approximation is needed to reduce the calculation to tractable form. Effects of the higher terms are most visible in the valley between the Thomas peak and the forward peak. The Thomas peak is visible in the correction term, even though it includes no second Born contributions.« less

Temperature dependence of the NO3 absorption spectrum

NASA Technical Reports Server (NTRS)

Sander, Stanley P.

1986-01-01

The absorption spectrum of the gas-phase NO3 radical has been studied between 220 and 700 nm by using both flash photolysis and discharge flow reactors for the production of NO3. In the flash photolysis method, cross sections at the peak of the (0,0) band at 661.9 nm were measured relative to the cross section of ClONO2 at several different wavelengths. From the best current measurements of the ClONO2 spectrum, the NO3 cross section at 661.9 nm was determined to be (2.28 + or 0.34) x 10 to the -17th sq cm/molecule at 298 K. Measurements at 230 K indicated that the cross section increases by a factor of 1.18 at the peak of the (0,0) band. The discharge flow method was used both to obtain absolute cross sections at 661.9 nm and to obtain relative absorption spectra between 300 and 700 nm at 298 and 230 K. A value of (1.83 + or - 0.27) x 10 to the -17th sq cm/molecule was obtained for sigma NO3 at 661.9 nm at 298 K. Upper limits to the NO3 cross sections were also measured between 220 and 260 nm with the discharge flow method.

Measurement of the neutron capture resonances for platinum using the Ge spectrometer and pulsed neutron beam at the J-PARC/MLF/ANNRI

NASA Astrophysics Data System (ADS)

Kino, Koichi; Hasemi, Hiroyuki; Kimura, Atsushi; Kiyanagi, Yoshiaki

2017-09-01

The neutron capture cross-section for platinum was measured at J-PARC/MLF/ANNRI. The intense pulsed neutron beam was impinging on a natural platinum foil sample and the emitted prompt γ-rays were detected by a Ge spectrometer. The peak energies of the low energy resonances for natural platinum are consistent with those of the JEFF-3.1.2, RUSFOND2010 and next-JENDL data libraries except for the 20-eV resonance. The resonance cross-sections of the next-JENDL library do not contradict the present measurements within the uncertainty of the absolute value of the present work. We analysed the prompt γ-ray spectrum and found a clear 7921.93 keV peak that originates from the transition from the 196Pt compound state to its ground state. The neutron capture cross-section for 195Pt was obtained by choosing events of this peak. The peak energies of most of the low energy resonances are almost consistent with those of the RUSFOND2010 and next-JENDL libraries. However, there was a disagreement for the 20-eV resonance.

Spectroscopy of high index contrast Yb:Ta2O5 waveguides for lasing applications

NASA Astrophysics Data System (ADS)

Aghajani, A.; Murugan, G. S.; Sessions, N. P.; Apostolopoulos, V.; Wilkinson, J. S.

2015-06-01

Ytterbium-doped waveguides are required for compact integrated lasers and Yb- doped Ta2O5 is a promising candidate material. The design, fabrication and spectroscopic characterisation of Yb:Ta2O5 rib waveguides are described. The peak absorption cross-section was measured to be 2.75×10-20 cm2 at 975 nm. The emission spectrum was found to have a fluorescence emission peak at a wavelength of 976 nm with a peak cross-section of 2.9×10-20 cm2 and a second broad fluorescence band spanning from 990 nm to 1090 nm. The excited- state life time was measured to be 260 μs.

Giant-pulse Nd:YVO4 microchip laser with MW-level peak power by emission cross-sectional control.

PubMed

Kausas, Arvydas; Taira, Takunori

2016-02-22

We present a giant-pulse generation laser realized by the emission cross-section control of a gain medium in a passively Q-switched Nd:YVO4 microchip laser with a Cr4+:YAG saturable absorber. Up to 1.17 MW peak power and 1.03 mJ pulse energy were obtained with a 100 Hz repetition rate. By combining the Nd:YVO4 crystal with a Sapphire plate, lower temperature difference between a pump region in the gain crystal and a crystal holder was obtained which helped to keep the cavity in stability zone at elevated temperatures and allowed the achievement of the high peak power for this laser system.

CEPXS

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

2015-10-19

CEPXS is a multigroup-Legendre cross-section generating code. The cross sections produced by CEPXS enable coupled electron-photon transport calculations to be performed with multigroup radiation transport codes, e.g. MITS and SCEPTRE. CEPXS generates multigroup-Legendre cross sections for photons, electrons and positrons over the energy range from 100 MeV to 1.0 keV. The continuous slowing-down approximation is used for those electron interactions that result in small-energy losses. The extended transport correction is applied to the forward-peaked elastic scattering cross section for electrons. A standard multigroup-Legendre treatment is used for the other coupled electron-photon cross sections. CEPXS extracts electron cross-section information from themore » DATAPAC data set and photon cross-section information from Biggs-Lighthill data. The model that is used for ionization/relaxation in CEPXS is essentially the same as that employed in ITS.« less

Temperature dependence of the 1.06-microm stimulated emission cross section of neodymium in YAG and in GSGG.

PubMed

Rapaport, Alexandra; Zhao, Shengzhi; Xiao, Guohua; Howard, Andrew; Bass, Michael

2002-11-20

A linear temperature dependence between -70 degrees C and +70 degrees C is reported for the peak stimulated emission cross section of Nd3+ ions in both yttrium aluminum garnet (YAG) and gadolinium scandium gallium garnet (GSGG).

State-resolved differential and integral cross sections for the Ne + H{sub 2}{sup +} (v = 0–2, j = 0) → NeH{sup +} + H reaction

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

Wu, Hui; Yao, Cui-Xia; He, Xiao-Hu

State-to-state quantum dynamic calculations for the proton transfer reaction Ne + H{sub 2}{sup +} (v = 0–2, j = 0) are performed on the most accurate LZHH potential energy surface, with the product Jacobi coordinate based time-dependent wave packet method including the Coriolis coupling. The J = 0 reaction probabilities for the title reaction agree well with previous results in a wide range of collision energy of 0.2-1.2 eV. Total integral cross sections are in reasonable agreement with the available experiment data. Vibrational excitation of the reactant is much more efficient in enhancing the reaction cross sections than translational andmore » rotational excitation. Total differential cross sections are found to be forward-backward peaked with strong oscillations, which is the indication of the complex-forming mechanism. As the collision energy increases, state-resolved differential cross section changes from forward-backward symmetric peaked to forward scattering biased. This forward bias can be attributed to the larger J partial waves, which makes the reaction like an abstraction process. Differential cross sections summed over two different sets of J partial waves for the v = 0 reaction at the collision energy of 1.2 eV are plotted to illustrate the importance of large J partial waves in the forward bias of the differential cross sections.« less

Eikonal approximation for proton-helium electron-capture processes

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

Kobayashi, K.; Toshima, N.; Ishihara, T.

1985-09-01

We calculate the capture cross sections for H/sup +/+He..-->..H+He/sup +/, treating the passive electron explicitly in a distorted-wave formalism based on the eikonal approximation. It is found that the shape of the differential cross sections is influenced considerably by the interaction between the passive electron and the incident proton, while the integrated cross sections are much less sensitive to that. The differential cross section at 293 keV agrees well with the experimental data except at extremely small scattering angles. The forward peak is reproduced well at higher energies. The integrated cross sections are in excellent agreement with experiments for themore » incident energy above 250 keV.« less

Search for $WZ/ZZ$ Production in the Lepton(s) + MET + Jets Channel with the CDF Experiment at the Tevatron Collider

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

Trovato, Marco

2014-01-01

In this thesis we present a search for the WZ and ZZ production in a final state ("W+2 jets") with a leptonically-decaying W and two energetic jets. We use the full dataset ( ∫ Ldt = 8:9 fb -1) recorded with the CDF detector at Fermilab. The challenge consists in extracting the small Z-hadronic peak from the large amount of background processes. Those processes also include the WW, whose hadronic peak cannot be distinguished from the Z peak, due to the poor calorimeter resolution. In the past such a signature was used to measure the diboson cross section, which ismore » highly dominated by the WW cross section.« less

Evidence for e+e-→γ ηc(1 S ) at center-of-mass energies between 4.01 and 4.60 GeV

NASA Astrophysics Data System (ADS)

Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chai, J.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; de Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dorjkhaidav, O.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Fegan, S.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garillon, B.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, S.; Gu, Y. T.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y. P.; Haddadi, Z.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, X. Q.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, S. H.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin, Y.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Khan, T.; Khoukaz, A.; Kiese, P.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuemmel, M.; Kuhlmann, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leithoff, H.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, K. J.; Li, Lei; Li, P. L.; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J. B.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, Ke; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Morello, G.; Muchnoi, N. Yu.; Muramatsu, H.; Mustafa, A.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.; Patteri, P.; Pelizaeus, M.; Pellegrino, J.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Pitka, A.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qi, T. Y.; Qian, S.; Qiao, C. F.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Richter, M.; Ripka, M.; Rolo, M.; Rong, G.; Rosner, Ch.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, J. J.; Song, W. M.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Tapan, I.; Tiemens, M.; Tsednee, B. T.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, Dan; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Wei, J. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Y. J.; Xiao, Z. J.; Xie, X. H.; Xie, Y. G.; Xie, Y. H.; Xiong, X. A.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. H.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Besiii Collaboration

2017-09-01

We present first evidence for the process e+e-→γ ηc(1 S ) at six center-of-mass energies between 4.01 and 4.60 GeV using data collected by the BESIII experiment operating at BEPCII. We measure the Born cross section at each energy using a combination of twelve ηc(1 S ) decay channels. We also combine all six energies under various assumptions for the energy-dependence of the cross section. If the process is assumed to proceed via the Y (4260 ), we measure a peak Born cross section σpeak(e+e-→γ ηc(1 S ))=2.11 ±0.49 (stat . )±0.36 (syst . ) pb with a statistical significance of 4.2 σ .

Effects of relativity of RTEX in collisions of U sup q+ with light targets

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

Chen, Mau Hsiung.

1990-11-07

We have calculated the resonant transfer and excitation cross sections in collisions of U{sup q+} (q = 82, 89, 90) ion with H{sub 2}, He and C in impulse approximation using the multi-configuration Dirac-Fock method. The calculations were carried out in intermediate coupling with configuration interaction. The quantum electrodynamic and finite nuclear size corrections were included in the calculations of transition energies. The Auger rates were calculated including the contributions from Coulomb as well as the transverse Breit interactions. For U{sup 89+} and U{sup 90+}, effects of relatively not only shift the peak positions but also change the peak structure.more » The total dielectronic recombination strength has been found to increase by 50% due to the effects of relativity. The present theoretical RTEX cross sections for U{sup 90+} in hydrogen agree well with experiment. For U{sup 82+}, Breit interaction had been found to have little effect on the RTEX cross sections involving L-shell excitation. However, the spin-orbit interaction can still make significant change in the peak structure. 24 refs., 4 figs.« less

Excitation Spectra and Brightness Optimization of Two-Photon Excited Probes

PubMed Central

Mütze, Jörg; Iyer, Vijay; Macklin, John J.; Colonell, Jennifer; Karsh, Bill; Petrášek, Zdeněk; Schwille, Petra; Looger, Loren L.; Lavis, Luke D.; Harris, Timothy D.

2012-01-01

Two-photon probe excitation data are commonly presented as absorption cross section or molecular brightness (the detected fluorescence rate per molecule). We report two-photon molecular brightness spectra for a diverse set of organic and genetically encoded probes with an automated spectroscopic system based on fluorescence correlation spectroscopy. The two-photon action cross section can be extracted from molecular brightness measurements at low excitation intensities, while peak molecular brightness (the maximum molecular brightness with increasing excitation intensity) is measured at higher intensities at which probe photophysical effects become significant. The spectral shape of these two parameters was similar across all dye families tested. Peak molecular brightness spectra, which can be obtained rapidly and with reduced experimental complexity, can thus serve as a first-order approximation to cross-section spectra in determining optimal wavelengths for two-photon excitation, while providing additional information pertaining to probe photostability. The data shown should assist in probe choice and experimental design for multiphoton microscopy studies. Further, we show that, by the addition of a passive pulse splitter, nonlinear bleaching can be reduced—resulting in an enhancement of the fluorescence signal in fluorescence correlation spectroscopy by a factor of two. This increase in fluorescence signal, together with the observed resemblance of action cross section and peak brightness spectra, suggests higher-order photobleaching pathways for two-photon excitation. PMID:22385865

Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

2016-09-01

We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

Multichannel processes of H2O in the 18 eV region

NASA Technical Reports Server (NTRS)

Wu, C. Y. Robert; Judge, D. L.

1988-01-01

Measurements were made of: (1) the fluorescence cross sections of OH(A 2Sigma+) fragments; (2) the absolute cross sections producing H atoms in the n = 2, 3, and 4 states; (3) the cross section for producing excited O atoms which has an upper limit of 5 x 10 to the -21 sq cm; and (4) the fluorescence cross section for producing H2(a 3Sigma g +) fragments. It is shown that, in the 16-20 eV region, there are excellent correspondences in the peak positions and spacings among the photoabsorption, photoionization spectra, and fluorescence functions of OH(A) and H(n).

Evidence for e + e - → γ η c ( 1 S ) at center-of-mass energies between 4.01 and 4.60 GeV

DOE PAGES

Ablikim, M.; Achasov, M. N.; Ahmed, S.; ...

2017-09-06

In this paper, we present first evidence for the process e +e - → γη c(1S) at six center-of-mass energies between 4.01 and 4.60 GeV using data collected by the BESIII experiment operating at BEPCII. We measure the Born cross section at each energy using a combination of twelve η c(1S) decay channels. We also combine all six energies under various assumptions for the energy-dependence of the cross section. Finally, if the process is assumed to proceed via the Y (4260), we measure a peak Born cross section σ peak (e +e - → γη c(1S)) = 2.11 ± 0.49(stat.)more » ± 0.36(syst.) pb with a statistical significance of 4.2σ.« less

Evidence for e + e - → γ η c ( 1 S ) at center-of-mass energies between 4.01 and 4.60 GeV

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

Ablikim, M.; Achasov, M. N.; Ahmed, S.

In this paper, we present first evidence for the process e +e - → γη c(1S) at six center-of-mass energies between 4.01 and 4.60 GeV using data collected by the BESIII experiment operating at BEPCII. We measure the Born cross section at each energy using a combination of twelve η c(1S) decay channels. We also combine all six energies under various assumptions for the energy-dependence of the cross section. Finally, if the process is assumed to proceed via the Y (4260), we measure a peak Born cross section σ peak (e +e - → γη c(1S)) = 2.11 ± 0.49(stat.)more » ± 0.36(syst.) pb with a statistical significance of 4.2σ.« less

Impact of electronic coupling, symmetry, and planarization on one- and two-photon properties of triarylamines with one, two, or three diarylboryl acceptors.

PubMed

Makarov, Nikolay S; Mukhopadhyay, Sukrit; Yesudas, Kada; Brédas, Jean-Luc; Perry, Joseph W; Pron, Agnieszka; Kivala, Milan; Müllen, Klaus

2012-04-19

We have performed a study of the one- and two-photon absorption properties of a systematically varied series of triarylamino-compounds with one, two, or three attached diarylborane arms arranged in linear dipolar, bent dipolar, and octupolar geometries. Two-photon fluorescence excitation spectra were measured over a wide spectral range with femtosecond laser pulses. We found that on going from the single-arm to the two- and three-arm systems, the peak in two-photon absorption (2PA) cross-section is suppressed by factors of 3-11 for the lowest excitonic level associated with the electronic coupling of the arms, whereas it is enhanced by factors of 4-8 for the higher excitonic level. These results show that the coupling of arms redistributes the 2PA cross-section between the excitonic levels in a manner that strongly favors the higher-energy excitonic level. The experimental data on one- and two-photon cross-sections, ground- and excited-state transition dipole moments, and permanent dipole moment differences between the ground and the lowest excited states were compared to the results obtained from a simple Frenkel exciton model and from highly correlated quantum-chemical calculations. It has been found that planarization of the structure around the triarylamine moiety leads to a sizable increase in peak 2PA cross-section for the lowest excitonic level of the two-arm system, whereas for the three-arm system, the corresponding peak was weakened and shifted to lower energy. Our studies show the importance of the interarm coupling, number of arms, and structural planarity on both the enhancement and the suppression of two-photon cross-sections in multiarm molecules. © 2012 American Chemical Society

1.083 μm laser operation in Nd,Mg:LiTaO3 crystal

NASA Astrophysics Data System (ADS)

Hu, P. C.; Hang, Y.; Li, R.; Gong, J.; Yin, J. G.; Zhao, C. C.; He, X. M.; Yu, T.; Zhang, L. H.; Chen, W. B.; Zhu, Y. Y.

2011-10-01

Nd,Mg:LiTaO3 single crystal with high optical quality was grown by Czochralski technique. Absorption and fluorescence spectra were investigated. The peak absorption cross section at 806.5 nm and peak emission cross section at 1091 nm are 6.81×10-20 and 3.28×10-20 cm2, respectively. The fluorescence lifetime was measured to be 129 μs. With a laser-diode as the pump source, a maximum 375 mW continuous-wave laser output at 1083 nm has been obtained with a slope efficiency of 7.2% with respect to the pump power.

Dissociative and double photoionization of CO from threshold to 90 A

NASA Technical Reports Server (NTRS)

Masuoka, T.; Samson, J. A. R.

1981-01-01

Partial cross sections for molecular photoionization (CO(+)), dissociative photoionization (C(+) and O(+)), and dissociative double photoionization (C(2+)) in CO have been measured from their thresholds to 90 A using techniques of mass spectrometry. The results are compared with data reported previously. Several peaks observed in the cross section curves for dissociated fragments are tentatively assigned by comparing with those in the photoelectron spectra reported for CO. It is concluded that the shoulder in the total absorption cross section curve between 400 and 90 A results solely from the dissociative ionization processes.

Bankfull characteristics of Ohio streams and their relation to peak streamflows

USGS Publications Warehouse

Sherwood, James M.; Huitger, Carrie A.

2005-01-01

Regional curves, simple-regression equations, and multiple-regression equations were developed to estimate bankfull width, bankfull mean depth, bankfull cross-sectional area, and bankfull discharge of rural, unregulated streams in Ohio. The methods are based on geomorphic, basin, and flood-frequency data collected at 50 study sites on unregulated natural alluvial streams in Ohio, of which 40 sites are near streamflow-gaging stations. The regional curves and simple-regression equations relate the bankfull characteristics to drainage area. The multiple-regression equations relate the bankfull characteristics to drainage area, main-channel slope, main-channel elevation index, median bed-material particle size, bankfull cross-sectional area, and local-channel slope. Average standard errors of prediction for bankfull width equations range from 20.6 to 24.8 percent; for bankfull mean depth, 18.8 to 20.6 percent; for bankfull cross-sectional area, 25.4 to 30.6 percent; and for bankfull discharge, 27.0 to 78.7 percent. The simple-regression (drainage-area only) equations have the highest average standard errors of prediction. The multiple-regression equations in which the explanatory variables included drainage area, main-channel slope, main-channel elevation index, median bed-material particle size, bankfull cross-sectional area, and local-channel slope have the lowest average standard errors of prediction. Field surveys were done at each of the 50 study sites to collect the geomorphic data. Bankfull indicators were identified and evaluated, cross-section and longitudinal profiles were surveyed, and bed- and bank-material were sampled. Field data were analyzed to determine various geomorphic characteristics such as bankfull width, bankfull mean depth, bankfull cross-sectional area, bankfull discharge, streambed slope, and bed- and bank-material particle-size distribution. The various geomorphic characteristics were analyzed by means of a combination of graphical and statistical techniques. The logarithms of the annual peak discharges for the 40 gaged study sites were fit by a Pearson Type III frequency distribution to develop flood-peak discharges associated with recurrence intervals of 2, 5, 10, 25, 50, and 100 years. The peak-frequency data were related to geomorphic, basin, and climatic variables by multiple-regression analysis. Simple-regression equations were developed to estimate 2-, 5-, 10-, 25-, 50-, and 100-year flood-peak discharges of rural, unregulated streams in Ohio from bankfull channel cross-sectional area. The average standard errors of prediction are 31.6, 32.6, 35.9, 41.5, 46.2, and 51.2 percent, respectively. The study and methods developed are intended to improve understanding of the relations between geomorphic, basin, and flood characteristics of streams in Ohio and to aid in the design of hydraulic structures, such as culverts and bridges, where stability of the stream and structure is an important element of the design criteria. The study was done in cooperation with the Ohio Department of Transportation and the U.S. Department of Transportation, Federal Highway Administration.

Closed-form expressions for state-to-state charge-transfer differential cross sections in a modified Faddeev three-body approach

NASA Astrophysics Data System (ADS)

Adivi, E. Ghanbari; Brunger, M. J.; Bolorizadeh, M. A.; Campbell, L.

2007-02-01

The second-order Faddeev-Watson-Lovelace approximation in a modified form is applied to charge transfer from hydrogenlike target atoms by a fully stripped energetic projectile ion. The state-to-state, nlm→n'l'm' , partial transition amplitudes are calculated analytically. The method is specifically applied to the collision of protons with hydrogen atoms, where differential cross sections of different transitions are calculated for incident energies of 2.8 and 5.0MeV . It is shown that the Thomas peak is present in all transition cross sections. The partial cross sections are then summed and compared with the available forward-angle experimental data, showing good agreement.

Positron collisions with acetylene calculated using the R-matrix with pseudo-states method

NASA Astrophysics Data System (ADS)

Zhang, Rui; Galiatsatos, Pavlos G.; Tennyson, Jonathan

2011-10-01

Eigenphase sums, total cross sections and differential cross sections are calculated for low-energy collisions of positrons with C2H2. The calculations demonstrate that the use of appropriate pseudo-state expansions very significantly improves the representation of this process giving both realistic eigenphases and cross sections. Differential cross sections are strongly forward peaked in agreement with the measurements. These calculations are computationally very demanding; even with improved procedures for matrix diagonalization, fully converged calculations are too expensive with current computer resources. Nonetheless, the calculations show clear evidence for the formation of a virtual state but no indication that acetylene actually binds a positron at its equilibrium geometry.

Absorption Cross-Sections of Sodium Diatomic Molecules

NASA Technical Reports Server (NTRS)

Fong, Zeng-Shevan

1985-01-01

The absorption cross sections of sodium dimers were studied using a heat pipe over operating in the non-heat-pipe mode. Three wavelength regions were observed. They are in the red, the green-blue, and the near ultraviolet regions. The absorption cross section depends on the wavelength of the incident light. Representative peak values for the v"=0 progression in the red and green-blue regions are 2.59 A sup 2 (average value) and 11.77 A sup 2 (T sub ave=624 K). The value for the C greater than X transitions is several tenths A sup 2. The cross sections were measured from absorption spectra taken as a function of temperature.

Strong-potential Born calculations for 1s-1s electron capture from atoms by protons

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

McGuire, J.H.; Kletke, R.E.; Sil, N.C.

1985-08-01

The strong-potential Born (SPB) approximation is examined by comparing various SPB calculations of high-velocity 1s-1s electron capture cross sections with one another and with experimental data. Above about 1 MeV, calculations using the SPB method of McGuire and Sil (SPMS) (Phys. Rev. A 28, 3679 (1983)) are in good agreement with total-cross-section observations for protons on H, He, C, Ne, and Ar as expected. For p+H and p+He, the SPB full-peaking (SPB-FP) approximation of Macek and Alston (Phys. Rev. A 26, 250 (1982)) and the SPB transverse-peaking (SPB-TP) approximation of Alston (Phys. Rev. A 27, 2342 (1982)) differ from ourmore » SPMS total cross sections by typically a factor of 2, as expected from general validity criteria. However, the differential cross sections at very forward angles (well within the Thomas angle) are the same in SPMS, SPB-FP, and SPB-TP methods in all cases. Below 1 MeV, cross sections obtained with use of various SPB methods differ considerably from one another, placing a limit of validity for these SPB calculations. We also suggest that in the gap between those energies where continuum intermediate states simply dominate, and above those energies where bound intermediate states simply dominate, detailed conceptual understanding of electron capture is incomplete.« less

Flooding and sedimentation in Wheeling Creek basin, Belmont County, Ohio

USGS Publications Warehouse

Kolva, J.R.; Koltun, G.F.

1987-01-01

The Wheeling Creek basin, which is located primarily in Belmont County, Ohio, experienced three damaging floods and four less severe floods during the 29-month period from February 1979 through June 1981. Residents of the basin became concerned about factors that could have affected the severity and frequency of out-of-bank floods. In response to those concerns, the U.S. Geological Survey, in cooperation with the Ohio Department of Natural Resources, undertook a study to estimate peak discharges and recurrence intervals for the seven floods of interest, provide information on current and historical mining-related stream-channel fill or scour, and examine storm-period subbasin contributions to the sediment load in Wheeling Creek. Streamflow data for adjacent basins, rainfall data, and, in two cases, flood-profile data were used in conjunction with streamflow data subsequently collected on Wheeling Creek to provide estimates of peak discharge for the seven floods that occurred from February 1979 through June 1981. Estimates of recurrence intervals were assigned to the Peak discharges on the basin of regional regression equations that relate selected basin characteristics to peak discharge with fixed recurrence intervals. These estimates indicate that a statistically unusual number of floods with recurrence intervals of 2 years or more occurred within that time period. Three cross sections located on Wheeling Creek and four located on tributaries were established and surveyed quarterly for approximately 2 years. No evidence of appreciable stream-channel fill or scour was observed at any of the cross sections, although minor profile changes were apparent at some locations. Attempts were made to obtain historical cross-section profile data for comparison with current cross-section profiles; however, no usable data were found. Excavations of stream-bottom materials were made near the three main-stem cross-section locations and near the mouth of Jug Run. The bottom materials were examined for evidence of recently deposited sediments of mining-related origin. The only evidence of appreciable mining-related sediment deposition was found at Jug Run, and, to a lesser extent, at one main-stem site.

Implications of the temperature dependence of Nd:YAG spectroscopic values for low temperature laser operation at 946 nm

NASA Astrophysics Data System (ADS)

Yoon, S. J.; Mackenzie, J. I.

2014-05-01

We present our measurements of the key spectroscopic properties over the temperature range of 77 K to 450 K for Nd3+ ions doped in Y3Al5O12 (YAG). From room to liquid nitrogen temperature (LNT), the peak absorption cross section around 808 nm increased by almost 3 times, in conjunction the bandwidth of this absorption line reduced by the same factor. At LNT the peak of the absorption line was blue shifted by 0.25 nm with respect to that at 300 K. The fluorescence spectrum between 850 nm - 1450 nm was measured, from which the emission cross sections for the three main transitions were calculated. One note of particular interest for the dominant emission wavelengths around 1064nm and 1061nm (4F3/2 --> 4I11/2) was the switch in their relative strength below 170K, and at LNT the 1061 nm line has almost twice the cross section as at 1064nm.. The fluorescence and lifetime of the upper laser level (4F3/2) was measured and the effective emission cross section determined by the Fuchtbauer-Ladenburg (F-L) method. The effective emission cross section for 946 nm (R1 --> Z5) increased by more than two times over the 300 K to 77 K range. A numerical fit for the temperature dependent emission cross section at 946 nm and 1064 nm and also calculated absorption coefficient at 808 nm pump diode laser have also obtained from the measured spectroscopic data.

Lift-enhancement in the gliding paradise tree snake

NASA Astrophysics Data System (ADS)

Krishnan, Anush; Barba, Lorena A.

2012-11-01

The paradise tree snake is a good glider, despite having no wing-like appendages. This snake jumps from tree branches, flattens its body and adopts an S-shape, then glides while undulating laterally in the air. Previous experimental studies in wind and water tunnels showed that the lift of the snake cross-section can peak markedly at about 35° angle of attack, a surprising feature that hints at a lift-enhancing mechanism. Here, we report numerical simulations on the snake cross-section using an immersed boundary method, which also show the peak in lift above a certain Reynolds number threshold. Our visualizations reveal a change in the vortex shedding pattern at that angle of attack. We also study variants of the cross-section, removing the anatomical overhanging lips on the fore and aft, and observe that they have a large impact on the flow field. The best performance is in fact obtained with the anatomically correct shape of the snake.

^235U(n,xnγ) Excitation Function Measurements Using Gamma-Ray Spectroscopy at GEANIE

NASA Astrophysics Data System (ADS)

Younes, W.; Becker, J. A.; Bernstein, L. A.; Archer, D. E.; Stoyer, M. A.; Hauschild, K.; Drake, D. M.; Johns, G. D.; Nelson, R. O.; Wilburn, S. W.

1998-04-01

The ^235U(n,xn) cross sections (where x<=2) have previously been measured at several incident neutron energies. In particular, the ^235U(n,2n) cross section has been measured(J. Frehaut et al.), Nucl. Sci. Eng. 74,29 (1980). reliably up to peak near E_n≈ 11 MeV, but not along the tail which is predicted by some(M.B. Chadwick, private communication.) codes to yield significant (e.g. >= 10% of peak) cross section out to E_n≈ 30 MeV. We have measured gamma-ray spectra resulting from ^235U(n,xn) as a function of neutron energy in the range 1 MeV <~ En <~ 200 MeV using the GEANIE spectrometer at the LANSCE/WNR ``white'' neutron source. We will present excitation functions for the de-excitation gamma rays in ^234,235U compared to predictions from the Hauser-Feshbach-preequilibrium code GNASH(M.B. Chadwick and P.G. Young, Los Alamos Report No. LA-UR-93-104, 1993.).

Tallness versus shrinkage: do women shrink with age or grow taller with recent birth date?

PubMed

Davies, K M; Recker, R R; Stegman, M R; Heaney, R P

1991-10-01

This paper presents evidence that much of the high rate of age-related height loss in women reported in cross-sectional studies is actually a cohort effect rather than an aging effect. Data from a large cross-sectional study of healthy, white American women indicate that there has been a gain in peak adult height of 1.0 cm per decade for several decades from 1900 through 1965. Data from the HES, HANES I, and HANES II studies concur on this point. By contrast, data from a longitudinal study of 191 healthy white U.S. women show only a trivial rate of decline from peak adult height in the fifth and sixth decades of life. In an unselected population, some apparent height loss with age is probably due to disease processes, such as vertebral collapse. Caution is needed in using aging to interpret differences in height and in height-dependent variables, such as bone density, in cross-sectional studies.

State-resolved differential cross-section measurement of Cl+C 2H 6→HCl+C 2H 5 reaction using single-beam velocity mapping

NASA Astrophysics Data System (ADS)

Samartzis, Peter C.; Smith, Derek J.; Rakitzis, T. Peter; Kitsopoulos, Theofanis N.

2000-07-01

The bimolecular reaction of atomic chlorine with ethane at a collision energy of 0.36 eV is studied in a single-beam experiment, using velocity mapping of a state-selected reaction product. The differential cross-section for HCl( v=0, J=1) product is directly determined from its Abel-inverted velocity map image. Our results are similar to previous measurements of the differential cross-section and suggest that the HCl( v=0, J=1) scattering is broad with a side-scattered peak. This Letter demonstrates the power of velocity mapping for measuring differential cross-sections for reactions for which one of the reactants is produced photolytically.

Electron capture to the continuum manifestation in fully differential cross sections for ion impact single ionization

NASA Astrophysics Data System (ADS)

Ciappina, M. F.; Fojón, O. A.; Rivarola, R. D.

2018-04-01

We present theoretical calculations of single ionization of He atoms by protons and multiply charged ions. The kinematical conditions are deliberately chosen in such a way that the ejected electron velocity matches the projectile impact velocity. The computed fully differential cross sections (FDCS) in the scattering plane using the continuum-distorted wave-eikonal initial state show a distinct peaked structure for a polar electron emission angle θ k = 0°. This element is absent when a first order theory is employed. Consequently, we can argue that this peak is a clear manifestation of a three-body effect, not observed before in FDCS. We discuss a possible interpretation of this new feature.

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

Y.H. Feng; X.X. Zhang; M.L. Wu

The coke descending behavior in a CDQ cooling shaft is studied experimentally by means of a tracing method with a digital camera. For three different blast-caps, the law of coke flow is studied under five conditions of coke charge. The experimental results show that, for the sake of the uniformity of the coke burden descending, a blast-cap with elliptical cross-section is a better choice than that with circular cross-section regardless of high or low placement. A coke charge pattern with a flat top burden surface is preferable to that with peak-valley surface, a double-peak superior to a one-peak. Trajectory andmore » average velocity distribution of coke behavior depend weakly on whether the coke is continuously fed or not as the discharging began. The blast-caps have local effects on the descending coke and hardly affect whether the cokes flow smoothly or not in the case of coke burden with enough depth.« less

Nuclear surface diffuseness revealed in nucleon-nucleus diffraction

NASA Astrophysics Data System (ADS)

Hatakeyama, S.; Horiuchi, W.; Kohama, A.

2018-05-01

The nuclear surface provides useful information on nuclear radius, nuclear structure, as well as properties of nuclear matter. We discuss the relationship between the nuclear surface diffuseness and elastic scattering differential cross section at the first diffraction peak of high-energy nucleon-nucleus scattering as an efficient tool in order to extract the nuclear surface information from limited experimental data involving short-lived unstable nuclei. The high-energy reaction is described by a reliable microscopic reaction theory, the Glauber model. Extending the idea of the black sphere model, we find one-to-one correspondence between the nuclear bulk structure information and proton-nucleus elastic scattering diffraction peak. This implies that we can extract both the nuclear radius and diffuseness simultaneously, using the position of the first diffraction peak and its magnitude of the elastic scattering differential cross section. We confirm the reliability of this approach by using realistic density distributions obtained by a mean-field model.

Study of DD Neutrons and their Transmission in Iron Spheres

NASA Astrophysics Data System (ADS)

Dhakal, Sushil

The Deuterium-Deuteron (DD) reaction has been used as a neutron source to study the transport of neutrons in natural iron. The scattering targets are used in the form of spheres and the neutron transmission measurement has been done at 7-MeV incident deuteron beam energy. The purpose of this study is to test the elastic and non-elastic neutron scattering cross sections for iron in the ENDF/B-VII data library, as some indications about the inaccuracy of those cross sections have been found from previous studies. The experiment has been carried out using the 4.5-MV tandem accelerator at Edwards Accelerator Laboratory at Ohio University, Athens, Ohio. The DD source reaction has been measured at 5- and 7-MeV deuteron beam energy. The D(d,n)3He monoenergetic reaction cross section has been measured from 0° to 135° at both 5- and 7-MeV beam energy and the D(d,np)D breakup reaction cross section has been measured up to 60° laboratory angles at 7-MeV beam energy. The target used is a deuterium gas cell of 3-cm length at approximately 2 atmosphere absolute pressure. The neutron energy is determined using the time of flight method. A NE213 liquid scintillation detector is used for neutron detection and the thick-target 27Al(d,n) reaction is used for the determination of neutron detector efficiency. The monoenergetic reaction cross section has been found to be in reasonable agreement with previous evaluations. The neutron transmission studies through iron spheres is done using two natural iron spheres with thicknesses of 3 and 8 cm. The DD source measurement (sphere-off) were repeated for the transmission studies and the neutron source was covered with the spheres for the transmission measurements. The experimental transmitted neutron spectrum is compared with the calculation done using Monte Carlo simulation code MCNP6.1 developed by Los Alamos National Laboratory. MCNP uses ENDF/B-VII.1 evaluated iron cross section for the simulation. The calculated and experimental neutron spectrum in time of flight has been compared at various laboratory angles from 0° to 150°. The calculated and experimental neutron time of flight spectra for neutron counts under the main peak (D(d,n)3He peak region) agree within the error bars for angles 90°, 135° and 150° for larger sphere (8-cm thickness) whereas they agree for all angles 0°, 15°, 30°, 45°, 90°, 135° and 150° for smaller sphere (3-cm thickness). However, the calculated and experimental neutron spectra show a difference of 12%, 11.80%, 16.85% and 19.67% in the main peak neutron counts for larger sphere at angles 0°, 15°, 30° and 45° respectively which can not be accounted for by the systematic uncertainty in our measurement (the 5% uncertainty in the target thickness and the 5% efficiency systematics are the main contributors). The sphere-off to on ratios for the calculation and the experiment also show a significant difference at those angles and this comparison is more robust as it avoids most of the systematic uncertainties including the efficiency. These differences likely come from the uncertainty in the ENDF cross section used. To test the ENDF cross section sensitivity, elastic cross section is decreased by 10% and inelastic cross section is increased by 14.78% in the energy range 7.2 to 11 MeV which corresponds to the energy range of the monoenergetic neutron peak for angles between 0° to 45°. This cross section modification keeps the total cross section constant on average in that energy range as the total in the library is assumed to be correct. This modification reduces the difference between the calculation and the experiment and brings it in agreement within the error bars. This result implies the possibility of underestimation of inelastic cross section in the above energy range and hence the overestimation of elastic cross section in the ENDF library.

Reduced channel conveyance on the Wichita River at Wichita Falls, Texas, 1900-2009

USGS Publications Warehouse

Winters, Karl; Baldys, Stanley; Schreiber, Russell

2010-01-01

Recent floods on the Wichita River at Wichita Falls, Texas, have reached higher stages compared to historical floods of similar magnitude discharges. The U.S. Geological Survey (USGS) has operated streamflow-gaging station 07312500 Wichita River at Wichita Falls, Tex., since 1938 and flood measurements near the location of the present gage were first made in 1900. Floods recorded in 2007 and 2008 at this gaging station, including the record flood of June 30, 2007, reached higher stages compared to historical floods before 1972 of similar peak discharges. For flood measurements made at stages of more than 18 feet, peak stages were about 1 to 3 feet higher compared to peak stages of similar peak discharges measured before 1972. Flood measurements made at stages of more than 18 feet also indicate a decrease in the measured mean velocity from about 3.5 to about 2.0 feet per second from 1941 to 2008. The increase in stage and decrease in streamflow velocity for similar magnitude floods indicates channel conveyance has decreased over time. A study to investigate the causes of reduced channel conveyance in the Wichita River reach from Loop 11 downstream to River Road in Wichita Falls was done by the USGS in cooperation with the City of Wichita Falls. Historical photographs indicate substantial growth of riparian vegetation downstream from Loop 11 between 1950 and 2009. Aerial photographs taken between 1950 and 2008 also indicate an increase in riparian vegetation. Twenty-five channel cross sections were surveyed by the USGS in this reach in 2009. These cross sections were located at bridge crossings or collocated with channel cross sections previously surveyed in 1986 for use in a floodplain mapping study by the Federal Emergency Management Agency. Four channel cross sections 3,400 to 11,900 feet downstream from Martin Luther King Jr. Boulevard indicate narrowing of the channel. The remaining channel cross sections surveyed in 2009 by the USGS compared favorably with cross sections surveyed in 1986 for the Federal Emergency Management Agency, with no substantial differences noted. Comparison of channel cross sections surveyed in 2009 to those from historic bridge plans indicate no change in cross section has occurred at most of the bridges from Loop 11 downstream to River Road in Wichita Falls, except for obstructions noted at the Scott Avenue bridge and Martin Luther King Jr. bridge. Although obstructions in the channel at these bridges only partially block flow, they could also be contributing to reduced channel conveyance. Step-backwater profiles were used by the USGS to verify channel roughness. The main channel roughness coefficients (Manning's n values) from 2009 surveys were virtually unchanged from those used in a 1991 hydraulic model done for the Federal Emergency Management Agency. The average overbank roughness coefficient (Manning's n value) was 0.15, more than double the value of 0.06 used in the 1991 hydraulic model. Increased overbank vegetation has resulted in higher stages conveying the same amount of discharge, particularly for discharges more than 4,000 cubic feet per second.

Distance within colloidal dimers probed by rotation-induced oscillations of scattered light.

PubMed

van Vliembergen, Roland W L; van IJzendoorn, Leo J; Prins, Menno W J

2016-01-25

Aggregation processes of colloidal particles are of broad scientific and technological relevance. The earliest stage of aggregation, when dimers appear in an ensemble of single particles, is very important to characterize because it opens routes for further aggregation processes. Furthermore, it represents the most sensitive phase of diagnostic aggregation assays. Here, we characterize dimers by rotating them in a magnetic field and by recording the angle dependence of light scattering. At small scattering angles, the scattering cross section can be approximated by the total cross-sectional area of the dimer. In contrast, at scattering angles around 90 degrees, we reveal that the dependence of the scattering cross section on the dimer angle shows a series of peaks per single 2π rotation of the dimers. These characteristics originate from optical interactions between the two particles, as we have verified with two-particle Mie scattering simulations. We have studied in detail the angular positions of the peaks. It appears from simulations that the influence of particle size polydispersity, Brownian rotation and refractive index on the angular positions of the peaks is relatively small. However, the angular positions of the peaks strongly depend on the distance between the particles. We find a good correspondence between measured data and calculations for a gap of 180 nm between particles having a diameter of 1 micrometer. The experiment and simulations pave the way for extracting distance-specific data from ensembles of dimerizing colloidal particles, with application for sensitive diagnostic aggregation assays.

Quantum tachyons

NASA Astrophysics Data System (ADS)

Tomaschitz, R.

2005-02-01

The interaction of superluminal radiation with matter in atomic bound-bound and bound-free transitions is investigated. We study transitions in the relativistic hydrogen atom effected by superluminal quanta. The superluminal radiation field is coupled by minimal substitution to the Dirac equation in a Coulomb potential. We quantize the interaction to obtain the transition matrix for induced and spontaneous superluminal radiation in hydrogen-like ions. The tachyonic photoelectric effect is scrutinized, the cross-sections for ground state ionization by transversal and longitudinal tachyons are derived. We examine the relativistic regime, high electronic ejection energies, as well as the first order correction to the non-relativistic cross-sections. In the ultra-relativistic limit, both the longitudinal and transversal cross-sections are peaked at small but noticeably different scattering angles. In the non-relativistic limit, the longitudinal cross-section has two maxima, and its minimum is located at the transversal maximum. Ionization cross-sections can thus be used to discriminate longitudinal radiation from transversal tachyons and photons.

Laser radar cross-section estimation from high-resolution image data.

PubMed

Osche, G R; Seeber, K N; Lok, Y F; Young, D S

1992-05-10

A methodology for the estimation of ladar cross sections from high-resolution image data of geometrically complex targets is presented. Coherent CO(2) laser radar was used to generate high-resolution amplitude imagery of a UC-8 Buffalo test aircraft at a range of 1.3 km at nine different aspect angles. The average target ladar cross section was synthesized from these data and calculated to be sigma(T) = 15.4 dBsm, which is similar to the expected microwave radar cross sections. The aspect angle dependence of the cross section shows pronounced peaks at nose on and broadside, which are also in agreement with radar results. Strong variations in both the mean amplitude and the statistical distributions of amplitude with the aspect angle have also been observed. The relative mix of diffuse and specular returns causes significant deviations from a simple Lambertian or Swerling II target, especially at broadside where large normal surfaces are present.

Thickness dependence of scattering cross-sections in quantitative scanning transmission electron microscopy.

PubMed

Martinez, G T; van den Bos, K H W; Alania, M; Nellist, P D; Van Aert, S

2018-04-01

In quantitative scanning transmission electron microscopy (STEM), scattering cross-sections have been shown to be very sensitive to the number of atoms in a column and its composition. They correspond to the integrated intensity over the atomic column and they outperform other measures. As compared to atomic column peak intensities, which saturate at a given thickness, scattering cross-sections increase monotonically. A study of the electron wave propagation is presented to explain the sensitivity of the scattering cross-sections. Based on the multislice algorithm, we analyse the wave propagation inside the crystal and its link to the scattered signal for the different probe positions contained in the scattering cross-section for detector collection in the low-, middle- and high-angle regimes. The influence to the signal from scattering of neighbouring columns is also discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of extracranial blood flow in Parkinson disease.

PubMed

Haktanir, Alpay; Yaman, Mehmet; Acar, Murat; Gecici, Omer; Demirel, Reha; Albayrak, Ramazan; Demirkirkan, Kemal

2006-01-02

Decreased cerebral flow velocities in Parkinsonian patients were reported previously. Because of the limited data on vascular changes in Parkinson disease (PD), which may have a vascular etiology, we aimed to disclose any possible cerebral hemodynamic alteration in Parkinsonian patients. We prospectively evaluated 28 non-demented, idiopathic parkinsonian patients and 19 age and sex matched controls with Doppler sonography. Flow volumes, peak systolic flow velocities, and cross-sectional areas of vertebral and internal carotid arteries (ICA) were measured and compared between patients and controls. Correlation of patient age and disease duration with Doppler parameters was observed; and each Doppler parameter of patients within each Hoehn-Yahr scale was compared. There was no significant difference of measured parameters between groups. No correlation was found between disease duration and age with flow volume, cross-sectional area or peak systolic velocity. Hoehn-Yahr scale was not found having significant relation with Doppler parameters. Values of vertebral, internal carotid and cerebral blood flow volumes (CBF), peak systolic velocities, and cross-sectional areas were not significantly different between Parkinsonian patients and age and sex matched controls. Although regional blood flow decreases may be seen as reported previously, Parkinson disease is not associated with a flow volume or velocity alteration of extracranial cerebral arteries.

Carotid Plaque Morphological Classification Compared With Biomechanical Cap Stress: Implications for a Magnetic Resonance Imaging-Based Assessment.

PubMed

Gijsen, Frank J H; Nieuwstadt, Harm A; Wentzel, Jolanda J; Verhagen, Hence J M; van der Lugt, Aad; van der Steen, Antonius F W

2015-08-01

Two approaches to target plaque vulnerability-a histopathologic classification scheme and a biomechanical analysis-were compared and the implications for noninvasive risk stratification of carotid plaques using magnetic resonance imaging were assessed. Seventy-five histological plaque cross sections were obtained from carotid endarterectomy specimens from 34 patients (>70% stenosis) and subjected to both a Virmani histopathologic classification (thin fibrous cap atheroma with <0.2-mm cap thickness, presumed vulnerable) and a peak cap stress computation (<140 kPa: presumed stable; >300 kPa: presumed vulnerable). To demonstrate the implications for noninvasive plaque assessment, numeric simulations of a typical carotid magnetic resonance imaging protocol were performed (0.62×0.62 mm(2) in-plane acquired voxel size) and used to obtain the magnetic resonance imaging-based peak cap stress. Peak cap stress was generally associated with histological classification. However, only 16 of 25 plaque cross sections could be labeled as high-risk (peak cap stress>300 kPa and classified as a thin fibrous cap atheroma). Twenty-eight of 50 plaque cross sections could be labeled as low-risk (a peak cap stress<140 kPa and not a thin fibrous cap atheroma), leading to a κ=0.39. 31 plaques (41%) had a disagreement between both classifications. Because of the limited magnetic resonance imaging voxel size with regard to cap thickness, a noninvasive identification of only a group of low-risk, thick-cap plaques was reliable. Instead of trying to target only vulnerable plaques, a more reliable noninvasive identification of a select group of stable plaques with a thick cap and low stress might be a more fruitful approach to start reducing surgical interventions on carotid plaques. © 2015 American Heart Association, Inc.

Scattering Properties of Ground-State 23Na Vapor Using Generalized Scattering Theory

NASA Astrophysics Data System (ADS)

Al-Harazneh, A. A.; Sandouqa, A. S.; Joudeh, B. R.; Ghassib, H. B.

2018-04-01

The scattering properties of ground-state 23Na vapor are investigated within the framework of the Galitskii-Migdal-Feynman formalism. Viewed as a generalized scattering theory, this formalism is used to calculate the medium phase shifts. The scattering properties of the system—the total, viscosity, spin-exchange, and average cross sections—are then computed using these phase shifts according to standard recipes. The total cross section is found to exhibit the Ramsauer-Townsend effect as well as resonance peaks. These peaks are caused by the large difference between the potentials for electronic spin-singlet and spin-triplet states. They represent quasi-bound states in the system. The results obtained for the complex spin-exchange cross sections are particularly highlighted because of their importance in the spectroscopy of the Na2 dimer. So are the results for the scattering lengths pertaining to both singlet and triplet states. Wherever possible, comparison is made with other published results.

27 CFR 9.193 - Rattlesnake Hills.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain Quadrangle... boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot peak of Elephant Mountain, section 16, T12N/R20E; then (3) Continues straight east-southeast, crossing...

27 CFR 9.193 - Rattlesnake Hills.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain Quadrangle... boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot peak of Elephant Mountain, section 16, T12N/R20E; then (3) Continues straight east-southeast, crossing...

27 CFR 9.193 - Rattlesnake Hills.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain Quadrangle... boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot peak of Elephant Mountain, section 16, T12N/R20E; then (3) Continues straight east-southeast, crossing...

27 CFR 9.193 - Rattlesnake Hills.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain Quadrangle... boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot peak of Elephant Mountain, section 16, T12N/R20E; then (3) Continues straight east-southeast, crossing...

27 CFR 9.193 - Rattlesnake Hills.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Yakima East Quadrangle, Washington—Yakima Co., 1953, photorevised 1985; (2) Elephant Mountain Quadrangle... boundary line— (2) Proceeds straight eastward, crossing onto the Elephant Mountain map, to the 2,192-foot peak of Elephant Mountain, section 16, T12N/R20E; then (3) Continues straight east-southeast, crossing...

Method and apparatus for identifying conductive objects by monitoring the true resistive component of impedance change in a coil system caused by the object

DOEpatents

Gregory, William D.; Capots, Larry H.; George, James P.; Janik, Richard

1981-01-01

The type of conductor, its property, and if a metal, its type and cross-sectional area can be obtained from measurements made at different frequencies for the amount of unbalance created in a previously balanced stable coil detection system. The true resistive component is accurately measured and thus reflects only the voltage loss attributable to eddy currents caused by introduction of the test sample to the coil system. This voltage divided by corresponding applied frequency gives a curve which peaks at a frequency dependent upon type of conductor. For a metal this peak frequency is proportional to the samples resistivity divided by its cross-sectional area.

Proton and deuteron double differential cross sections at angles from 10 deg to 60 deg from Be, C, Al, Fe, Cu, Ge, W, and Pb under 558-MeV-proton irradiation

NASA Technical Reports Server (NTRS)

Beck, S. M.; Powell, C. A.

1976-01-01

The double differential cross sections for the production of protons and deuterons from targets of Be, C, Al, Fe, Cu, Ge, W, and Pb were obtained at laboratory angles of scatter of 10, 20, 30, 40, 50, and 60 degrees for 558-MeV incident protons. The position of the quasi-elastic peak, discernible in the cross sections up to approximately 40 degrees, corresponded closely to the theoretical predictions for proton-proton elastic scattering at 558 MeV. The mean ratio of deuteron to proton energy-integrated cross sections was 0.056 + or - 0.008. The dependence of energy-integrated cross sections for both protons and deuterons on target mass number A varied from A to the 1/3 power at 10 degrees to A to the 2/3 power above approximately 30 degrees. The ratio of energy-integrated deuteron cross sections for quasielastic processes to that for reactions yielding a deuteron-pi-meson pair was approximately 10 percent.

Fokker-Planck-Based Acceleration for SN Equations with Highly Forward Peaked Scattering in Slab Geometry

NASA Astrophysics Data System (ADS)

Patel, Japan

Short mean free paths are characteristic of charged particles. High energy charged particles often have highly forward peaked scattering cross sections. Transport problems involving such charged particles are also highly optically thick. When problems simultaneously have forward peaked scattering and high optical thickness, their solution, using standard iterative methods, becomes very inefficient. In this dissertation, we explore Fokker-Planck-based acceleration for solving such problems.

A New Scaling Law of Resonance in Total Scattering Cross Section in Gases

NASA Astrophysics Data System (ADS)

Raju, Gorur Govinda

2009-10-01

Electrical discharges in gases continue to be an active area of research because of industrial applications such as power systems, environmental clean up, laser technology, semiconductor fabrication etc. A fundamental knowledge of electron-gas neutral interaction is indispensable and, the total scattering cross section is one of the quantities that have been measured extensively. The energy dependence of the total cross sections shows peaks or resonance processes that are operative in the collision process. These peaks and the energies at which they occur are shown to satisfy a broad relationship involving the polarizability and the dipole moment of the target particle. Data on 62 target particles belonging to the following species are analyzed. (Eq 1) Rare gas atoms (Eq 2) Di-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties Poly-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties. Methods of improving the newly identified scaling law and possible application have been identified. 1 INTRODUCTION: Data on electron-neutral interactions are one of the most fundamental in the study of gaseous electronics and an immense literature, both experimental and theoretical, has become available since about the year 1920. [1-5]. In view of the central role which these data play in all facets of gas discharges and plasma science, it is felt that a critical review of available data is timely, mainly for the community of high voltage engineers and industries connected with plasma science in general. The electron-neutral interaction, often referred to as scattering in the scientific literature, is quantified by using the quantity called the total scattering cross section (QT, m^2). In the literature on cross section, total cross section and total scattering cross section are terms used synonymously and we follow the same practice. A definition may be found in reference [1]. This paper concerns scaling of total cross section of gases at resonance energy and the electron energy at which resonance occurs. The meaning of resonance is briefly explained in the following section. Here, we use the term scaling to relate the two quantities mentioned, namely, the resonance energy and the total cross section at that energy. Consistent with the definition of scaling, if the law proposed holds, one of the two quantities mentioned above may be calculated if the other is known. Such a method is very useful in gas discharge modeling and calculation of breakdown voltages, as more fully explained in the later section of the paper. 2 DESCRIPTION OF RESONANCE: A brief description of resonance phenomena in several types of target particles, viz., atomic, poly atomic, polar, non-polar phenomena are presented. 3 PREVIOUS SCALING LAWS: A common representation of a given characteristic with as few adjustable parameters as possible is generally known as the scaling law. The Paschen curve for breakdown voltage is such a familiar scaling law. With reference to cross sections several attempts have been made to obtain a scaling law, with varying degree of success. If the cross section-energy curve is qualitatively similar without having sharp peaks and oscillations, moderately successful scaling laws may be devised. For example, the ionization cross section- energy curves for most gases follow a general pattern. Several published scaling laws are discussed. 4 A NEW SCALING LAW AND DISCUSSION: In this work the author has compiled the resonance details for more than 60 gasest hat include the range from simple atoms to complex molecules that are polyatomic, dipolar, electron-attaching and isomers. The target particles exhibit a number of distinct features, as far as their total cross section variation with electron energy is concerned as already explained.

The age of peak performance in Ironman triathlon: a cross-sectional and longitudinal data analysis

PubMed Central

2013-01-01

Background The aims of the present study were, firstly, to investigate in a cross-sectional analysis the age of peak Ironman performance within one calendar year in all qualifiers for Ironman Hawaii and Ironman Hawaii; secondly, to determine in a longitudinal analysis on a qualifier for Ironman Hawaii whether the age of peak Ironman performance and Ironman performance itself change across years; and thirdly, to determine the gender difference in performance. Methods In a cross-sectional analysis, the age of the top ten finishers for all qualifier races for Ironman Hawaii and Ironman Hawaii was determined in 2010. For a longitudinal analysis, the age and the performance of the annual top ten female and male finishers in a qualifier for Ironman Hawaii was determined in Ironman Switzerland between 1995 and 2010. Results In 19 of the 20 analyzed triathlons held in 2010, there was no difference in the age of peak Ironman performance between women and men (p > 0.05). The only difference in the age of peak Ironman performance between genders was in ‘Ironman Canada’ where men were older than women (p = 0.023). For all 20 races, the age of peak Ironman performance was 32.2 ± 1.5 years for men and 33.0 ± 1.6 years for women (p > 0.05). In Ironman Switzerland, there was no difference in the age of peak Ironman performance between genders for top ten women and men from 1995 to 2010 (F = 0.06, p = 0.8). The mean age of top ten women and men was 31.4 ± 1.7 and 31.5 ± 1.7 years (Cohen's d = 0.06), respectively. The gender difference in performance in the three disciplines and for overall race time decreased significantly across years. Men and women improved overall race times by approximately 1.2 and 4.2 min/year, respectively. Conclusions Women and men peak at a similar age of 32–33 years in an Ironman triathlon with no gender difference. In a qualifier for Ironman Hawaii, the age of peak Ironman performance remained unchanged across years. In contrast, gender differences in performance in Ironman Switzerland decreased during the studied period, suggesting that elite female Ironman triathletes might still narrow the gender gap in the future. PMID:24004814

Meson Production and Space Radiation

NASA Astrophysics Data System (ADS)

Norbury, John; Blattnig, Steve; Norman, Ryan; Aghara, Sukesh

Protecting astronauts from the harmful effects of space radiation is an important priority for long duration space flight. The National Council on Radiation Protection (NCRP) has recently recommended that pion and other mesons should be included in space radiation transport codes, especially in connection with the Martian atmosphere. In an interesting accident of nature, the galactic cosmic ray spectrum has its peak intensity near the pion production threshold. The Boltzmann transport equation is structured in such a way that particle production cross sec-tions are multiplied by particle flux. Therefore, the peak of the incident flux of the galactic cosmic ray spectrum is more important than other regions of the spectrum and cross sections near the peak are enhanced. This happens with pion cross sections. The MCNPX Monte-Carlo transport code now has the capability of transporting heavy ions, and by using a galactic cosmic ray spectrum as input, recent work has shown that pions contribute about twenty percent of the dose from galactic cosmic rays behind a shield of 20 g/cm2 aluminum and 30 g/cm2 water. It is therefore important to include pion and other hadron production in transport codes designed for space radiation studies, such as HZETRN. The status of experimental hadron production data for energies relevant to space radiation will be reviewed, as well as the predictive capa-bilities of current theoretical hadron production cross section and space radiation transport models. Charged pions decay into muons and neutrinos, and neutral pions decay into photons. An electromagnetic cascade is produced as these particles build up in a material. The cascade and transport of pions, muons, electrons and photons will be discussed as they relate to space radiation. The importance of other hadrons, such as kaons, eta mesons and antiprotons will be considered as well. Efficient methods for calculating cross sections for meson production in nucleon-nucleon and nucleus-nucleus reactions will be presented. The NCRP has also recom-mended that more attention should be paid to neutron and light ion transport. The coupling of neutrons, light ions, mesons and other hadrons will be discussed.

Determination of differential cross sections for electron-impact excitation of electronic states of molecular oxygen

NASA Astrophysics Data System (ADS)

Campbell, L.; Green, M. A.; Brunger, M. J.; Teubner, P. J.; Cartwright, D. C.

2000-02-01

The development and initial results of a method for the determination of differential cross sections for electron scattering by molecular oxygen are described. The method has been incorporated into an existing package of computer programs which, given spectroscopic factors, dissociation energies and an energy-loss spectrum for electron-impact excitation, determine the differential cross sections for each electronic state relative to that of the elastic peak. Enhancements of the original code were made to deal with particular aspects of electron scattering from O2, such as the overlap of vibrational levels of the ground state with transitions to excited states, and transitions to levels close to and above the dissocation energy in the Herzberg and Schumann-Runge continua. The utility of the code is specifically demonstrated for the ``6-eV states'' of O2, where we report absolute differential cross sections for their excitation by 15-eV electrons. In addition an integral cross section, derived from the differential cross section measurements, is also reported for this excitation process and compared against available theoretical results. The present differential and integral cross sections for excitation of the ``6-eV states'' of O2 are the first to be reported in the literature for electron-impact energies below 20 eV.

Culvert Analysis Program Graphical User Interface 1.0--A preprocessing and postprocessing tool for estimating flow through culvert

USGS Publications Warehouse

Bradley, D. Nathan

2013-01-01

The peak discharge of a flood can be estimated from the elevation of high-water marks near the inlet and outlet of a culvert after the flood has occurred. This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as high-water marks on trees or buildings. When combined with the cross-sectional geometry of the channel upstream from the culvert and the culvert size, shape, roughness, and orientation, the high-water marks define a water-surface profile that can be used to estimate the peak discharge by using the methods described by Bodhaine (1968). This type of measurement is in contrast to a “direct” measurement of discharge made during the flood where cross-sectional area is measured and a current meter or acoustic equipment is used to measure the water velocity. When a direct discharge measurement cannot be made at a streamgage during high flows because of logistics or safety reasons, an indirect measurement of a peak discharge is useful for defining the high-flow section of the stage-discharge relation (rating curve) at the streamgage, resulting in more accurate computation of high flows. The Culvert Analysis Program (CAP) (Fulford, 1998) is a command-line program written in Fortran for computing peak discharges and culvert rating surfaces or curves. CAP reads input data from a formatted text file and prints results to another formatted text file. Preparing and correctly formatting the input file may be time-consuming and prone to errors. This document describes the CAP graphical user interface (GUI)—a modern, cross-platform, menu-driven application that prepares the CAP input file, executes the program, and helps the user interpret the output

Electron impact ionization of cycloalkanes, aldehydes, and ketones

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

Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

The theoretical calculations of electron impact total ionization cross section for cycloalkane, aldehyde, and ketone group molecules are undertaken from ionization threshold to 2 keV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionization contribution method. The results of most of the targets studied compare fairly well with the recent measurements, wherever available and the cross sections for many targets are predicted for the first time. The correlation between the peak of ionization cross sections with number of target electrons and target parameters is also reported. It was found that the crossmore » sections at their maximum depend linearly with the number of target electrons and with other target parameters, confirming the consistency of the values reported here.« less

Secondary neutron-production cross sections from heavy-ioninteractions in composite targets.

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

Heilbronn, L.; Iwata, Y.; Iwase,H.

Secondary neutron-production cross-sections have been measured from interactions of 290 MeV/nucleon C and 600 MeV/nucleon Ne in a target composed of simulated Martian regolith and polyethylene, and from 400 MeV/nucleon Ne interactions in wall material from the International Space Station. The data were measured between 5 and 80 deg in the laboratory. We report the double-differential cross sections, angular distributions, and total neutron-production cross sections from all three systems. The spectra from all three systems exhibit behavior previously reported in other heavy-ion, neutron production experiments; namely, a peak at forward angles near the energy corresponding to the beam velocity, withmore » the remaining spectra generated by pre-equilibrium and equilibrium processes. The double differential cross sections are fitted with a moving-source parameterization. Also reported are the data without corrections for neutron flux attenuation in the target and other intervening materials, and for neutron production in non-target materials near the target position. These uncorrected spectra are compared with SHIELD-HIT and PHITS transport model calculations. The transport model calculations reproduce the spectral shapes well, but, on average, underestimate the magnitudes of the cross sections.« less

Secondary neutron-production cross sections from heavy-ion interactions in composite targets

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

Heilbronn, L.; Iwata, Y.; Murakami, T.

Secondary neutron-production cross sections have been measured from interactions of 290 MeV/nucleon C and 600 MeV/nucleon Ne in a target composed of simulated Martian regolith and polyethylene, and from 400 MeV/nucleon Ne interactions in wall material from the International Space Station. The data were measured between 5 deg. and 80 deg. in the laboratory. We report the double-differential cross sections, angular distributions, and total neutron-production cross sections from all three systems. The spectra from all three systems exhibit behavior previously reported in other heavy-ion neutron-production experiments, namely, a peak at forward angles near the energy corresponding to the beam velocity,more » with the remaining spectra generated by pre-equilibrium and equilibrium processes. The double-differential cross sections are fitted with a moving-source parametrization. Also reported are the data without corrections for neutron flux attenuation in the target and other intervening materials and for neutron production in nontarget materials near the target position. These uncorrected spectra are compared with SHIELD-HIT and PHITS transport model calculations. The transport model calculations reproduce the spectral shapes well but, on average, underestimate the magnitudes of the cross sections.« less

Obtaining Cross-Sections of Paint Layers in Cultural Artifacts Using Femtosecond Pulsed Lasers

PubMed Central

Harada, Takaaki; Spence, Stephanie; Margiolakis, Athanasios; Deckoff-Jones, Skylar; Ploeger, Rebecca; Shugar, Aaron N.; Hamm, James F.; Dani, Keshav M.; Dani, Anya R.

2017-01-01

Recently, ultrafast lasers exhibiting high peak powers and extremely short pulse durations have created a new paradigm in materials processing. The precision and minimal thermal damage provided by ultrafast lasers in the machining of metals and dielectrics also suggests a novel application in obtaining precise cross-sections of fragile, combustible paint layers in artwork and cultural heritage property. Cross-sections of paint and other decorative layers on artwork provide critical information into its history and authenticity. However, the current methodology which uses a scalpel to obtain a cross-section can cause further damage, including crumbling, delamination, and paint compression. Here, we demonstrate the ability to make controlled cross-sections of paint layers with a femtosecond pulsed laser, with minimal damage to the surrounding artwork. The femtosecond laser cutting overcomes challenges such as fragile paint disintegrating under scalpel pressure, or oxidation by the continuous-wave (CW) laser. Variations in laser power and translational speed of the laser while cutting exhibit different benefits for cross-section sampling. The use of femtosecond lasers in studying artwork also presents new possibilities in analyzing, sampling, and cleaning of artwork with minimal destructive effects. PMID:28772468

Obtaining Cross-Sections of Paint Layers in Cultural Artifacts Using Femtosecond Pulsed Lasers.

PubMed

Harada, Takaaki; Spence, Stephanie; Margiolakis, Athanasios; Deckoff-Jones, Skylar; Ploeger, Rebecca; Shugar, Aaron N; Hamm, James F; Dani, Keshav M; Dani, Anya R

2017-01-26

Recently, ultrafast lasers exhibiting high peak powers and extremely short pulse durations have created a new paradigm in materials processing. The precision and minimal thermal damage provided by ultrafast lasers in the machining of metals and dielectrics also suggests a novel application in obtaining precise cross-sections of fragile, combustible paint layers in artwork and cultural heritage property. Cross-sections of paint and other decorative layers on artwork provide critical information into its history and authenticity. However, the current methodology which uses a scalpel to obtain a cross-section can cause further damage, including crumbling, delamination, and paint compression. Here, we demonstrate the ability to make controlled cross-sections of paint layers with a femtosecond pulsed laser, with minimal damage to the surrounding artwork. The femtosecond laser cutting overcomes challenges such as fragile paint disintegrating under scalpel pressure, or oxidation by the continuous-wave (CW) laser. Variations in laser power and translational speed of the laser while cutting exhibit different benefits for cross-section sampling. The use of femtosecond lasers in studying artwork also presents new possibilities in analyzing, sampling, and cleaning of artwork with minimal destructive effects.

Understanding Differences in the Body Burden–Age Relationships of Bioaccumulating Contaminants Based on Population Cross Sections versus Individuals

PubMed Central

Quinn, Cristina L.

2012-01-01

Background: Body burdens of persistent bioaccumulative contaminants estimated from the cross-sectional biomonitoring of human populations are often plotted against age. Such relationships have previously been assumed to reflect the role of age in bioaccumulation. Objectives: We used a mechanistic modeling approach to reproduce concentration-versus-age relationships and investigate factors that influence them. Method: CoZMoMAN is an environmental fate and human food chain bioaccumulation model that estimates time trends in human body burdens in response to time-variant environmental emissions. Trends of polychlorinated biphenyl (PCB) congener 153 concentrations versus age for population cross sections were estimated using simulated longitudinal data for individual women born at different times. The model was also used to probe the influence of partitioning and degradation properties, length of emissions, and model assumptions regarding lipid content and liver metabolism on concentration–age trends of bioaccumulative and persistent contaminants. Results: Body burden–age relationships for population cross sections and individuals over time are not equivalent. The time lapse between the peak in emissions and sample collection for biomonitoring is the most influential factor controlling the shape of concentration–age trends for chemicals with human metabolic half-lives longer than 1 year. Differences in observed concentration–age trends for PCBs and polybrominated diphenyl ethers are consistent with differences in emission time trends and human metabolic half-lives. Conclusions: Bioaccumulation does not monotonically increase with age. Our model suggests that the main predictors of cross-sectional body burden trends with age are the amount of time elapsed after peak emissions and the human metabolic and environmental degradation rates. PMID:22472302

Sensitivity of outflow peaks and flood stages to the selection of dam breach parameters and simulation models

NASA Astrophysics Data System (ADS)

Singh, Krishan P.; Snorrason, Arni

1984-02-01

Important breach parameters were identified and their ranges were estimated from a detailed study of historical earthdam failures due to overtopping. The U.S. Army Corps of Engineers Hydrologic Engineering Center (HEC) and the National Weather Service (NWS) dam breach models were chosen for evaluation and simulation. Both models use similar input data and breach descriptions, but the HEC uses the hydrologic routing method (modified Puls method), whereas the NWS uses the St. Vénant equations for routing. Information on eight dams in Illinois was taken from the Corps of Engineers inspection reports, and surveyed cross-sections of the downstream channels were supplied by the Division of Water Resources of the Illinois Department of Transportation. Various combinations of breach parameters (failure time, TF; depth of overtopping, hf; and breach size, B) were used for breach simulations by both methods with the 1.00PMF, 0.50PMF and 0.25PMF (probable maximum flood) inflow hydrographs. In general, the flood stage profiles predicted by the NWS were smoother and more reasonable than those predicted by the HEC. For channels with relatively steep slopes, the methods compared fairly well, whereas for the channels with mild slope, the HEC model often predicted oscillating, erratic flood stages, mainly due to its inability to route flood waves satisfactorily in non-prismatic channels. The breach outflow peaks are affected significantly by B but less so by hf. The ratio of outflow peak to inflow peak and the effect of TF on outflow decrease as the drainage area above the dam and impounded storage increase. Flood stage profiles predicted with cross-sections taken from 7.5' maps compared favorably with those predicted using surveyed cross-sections. For the range of breach parameters studied, the range of outflow peaks and flood stages downstream from the dam can be determined for regulatory and disaster prevention measures.

Peak discharge, flood frequency, and peak stage of floods on Big Cottonwood Creek at U.S. Highway 50 near Coaldale, Colorado, and Fountain Creek below U.S. Highway 24 in Colorado Springs, Colorado, 2016

USGS Publications Warehouse

Kohn, Michael S.; Stevens, Michael R.; Mommandi, Amanullah; Khan, Aziz R.

2017-12-14

The U.S. Geological Survey (USGS), in cooperation with the Colorado Department of Transportation, determined the peak discharge, annual exceedance probability (flood frequency), and peak stage of two floods that took place on Big Cottonwood Creek at U.S. Highway 50 near Coaldale, Colorado (hereafter referred to as “Big Cottonwood Creek site”), on August 23, 2016, and on Fountain Creek below U.S. Highway 24 in Colorado Springs, Colorado (hereafter referred to as “Fountain Creek site”), on August 29, 2016. A one-dimensional hydraulic model was used to estimate the peak discharge. To define the flood frequency of each flood, peak-streamflow regional-regression equations or statistical analyses of USGS streamgage records were used to estimate annual exceedance probability of the peak discharge. A survey of the high-water mark profile was used to determine the peak stage, and the limitations and accuracy of each component also are presented in this report. Collection and computation of flood data, such as peak discharge, annual exceedance probability, and peak stage at structures critical to Colorado’s infrastructure are an important addition to the flood data collected annually by the USGS.The peak discharge of the August 23, 2016, flood at the Big Cottonwood Creek site was 917 cubic feet per second (ft3/s) with a measurement quality of poor (uncertainty plus or minus 25 percent or greater). The peak discharge of the August 29, 2016, flood at the Fountain Creek site was 5,970 ft3/s with a measurement quality of poor (uncertainty plus or minus 25 percent or greater).The August 23, 2016, flood at the Big Cottonwood Creek site had an annual exceedance probability of less than 0.01 (return period greater than the 100-year flood) and had an annual exceedance probability of greater than 0.005 (return period less than the 200-year flood). The August 23, 2016, flood event was caused by a precipitation event having an annual exceedance probability of 1.0 (return period of 1 year, or the 1-year storm), which is a statistically common (high probability) storm. The Big Cottonwood Creek site is downstream from the Hayden Pass Fire burn area, which dramatically altered the hydrology of the watershed and caused this statistically rare (low probability) flood from a statistically common (high probability) storm. The peak flood stage at the cross section closest to the U.S. Highway 50 culvert was 6,438.32 feet (ft) above the North American Datum of 1988 (NAVD 88).The August 29, 2016, flood at the Fountain Creek site had an estimated annual exceedance probability of 0.5505 (return period equal to the 1.8-year flood). The August 29, 2016, flood event was caused by a precipitation event having an annual exceedance probability of 1.0 (return period of 1 year, or the 1-year storm). The peak stage during this flood at the cross section closest to the U.S. Highway 24 bridge was 5,832.89 ft (NAVD 88).Slope-area indirect discharge measurements were carried out at the Big Cottonwood Creek and Fountain Creek sites to estimate peak discharge of the August 23, 2016, flood and August 29, 2016, flood, respectively. The USGS computer program Slope-Area Computation Graphical User Interface was used to compute the peak discharge by adding the surveyed cross sections with Manning roughness coefficient assignments to the high-water marks. The Manning roughness coefficients for each cross section were estimated in the field using the Cowan method.

Slope-Area Computation Program Graphical User Interface 1.0—A Preprocessing and Postprocessing Tool for Estimating Peak Flood Discharge Using the Slope-Area Method

USGS Publications Warehouse

Bradley, D. Nathan

2012-01-01

The slope-area method is a technique for estimating the peak discharge of a flood after the water has receded (Dalrymple and Benson, 1967). This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as high-water marks (HWMs) on trees or buildings. These indicators of flood stage are combined with measurements of the cross-sectional geometry of the stream, estimates of channel roughness, and a mathematical model that balances the total energy of the flow between cross sections. This is in contrast to a “direct” measurement of discharge during the flood where cross-sectional area is measured and a current meter or acoustic equipment is used to measure the water velocity. When a direct discharge measurement cannot be made at a gage during high flows because of logistics or safety reasons, an indirect measurement of a peak discharge is useful for defining the high-flow section of the stage-discharge relation (rating curve) at the stream gage, resulting in more accurate computation of high flows. The Slope-Area Computation program (SAC; Fulford, 1994) is an implementation of the slope-area method that computes a peak-discharge estimate from inputs of water-surface slope (from surveyed HWMs), channel geometry, and estimated channel roughness. SAC is a command line program written in Fortran that reads input data from a formatted text file and prints results to another formatted text file. Preparing the input file can be time-consuming and prone to errors. This document describes the SAC graphical user interface (GUI), a crossplatform “wrapper” application that prepares the SAC input file, executes the program, and helps the user interpret the output. The SAC GUI is an update and enhancement of the slope-area method (SAM; Hortness, 2004; Berenbrock, 1996), an earlier spreadsheet tool used to aid field personnel in the completion of a slope-area measurement. The SAC GUI reads survey data, develops a plan-view plot, water-surface profile, cross-section plots, and develops the SAC input file. The SAC GUI also develops HEC-2 files that can be imported into HEC–RAS.

Single electron impact ionization of the methane molecule

NASA Astrophysics Data System (ADS)

Bouamoud, Mammar; Sahlaoui, Mohammed; Benmansour, Nour El Houda; Atomic and Molecular Collisions Team

2014-10-01

Triply differential cross sections (TDCS) results of electron-impact ionization of the inner 2a1 molecular orbital of CH4 are presented in the framework of the Second Born Approximation and compared with the experimental data performed in coplanar asymmetric geometry. The cross sections are averaged on the random orientations of the molecular target for accurate comparison with experiments and are compared also with the theoretical calculations of the Three Coulomb wave (3CW) model. Our results are in good agreement with experiments and 3CW results in the binary peak. In contrast the Second Born Approximation yields a significant higher values compared to the 3CW results for the recoil peak and seems to describe suitably the recoil region where higher order effects can occur with the participation of the recoiling ion in the collision process.

Integral cross sections for the direct excitation of the A 3 (sigma) u +, B 3 (pi) g, W 3 (delta) u, B' 3 (sigma) u -, a' 1 (sigma) u -, a 1 (pi) g, w 1 (delta) u, and C 3 (pi) u electronic states in

NASA Technical Reports Server (NTRS)

Johnson, P. V.; Malone, C. P.; Kanik, I.

2005-01-01

Integral cross sections for electron impact excitation out of the ground state (X 1(sigma)g +) to the A 3(sigma)u +, B 3(pi)g, W 3(delta)u, B' 3(sigma)u -, a' 1(sigma)u -, a 1(pi)g, w 1(delta)u, and states in N2 are reported at incident energies ranging between 10 and 100 eV. These data have been derived by integrating differential cross sections previously reported by this group. New differential cross section measurements for the a 1(pi)g state at 200 eV are also presented to extend the range of the reported integral cross sections for this state, which is responsible for the emissions of the Lyman-Birge-Hopfield band system (a 1(pi)g (rightwards arrow) X 1(sigma)g +). The present results are compared and critically evaluated against existing cross sec In general, the present cross sections are smaller than previous results at low impact energies from threshold through the excitation function peak regions. These lower cross sections have potentially significant implications on our understanding of UV emissions in the atmospheres of Earth and Titan.

Independent control of beam astigmatism and ellipticity using a SLM for fs-laser waveguide writing.

PubMed

Ruiz de la Cruz, A; Ferrer, A; Gawelda, W; Puerto, D; Sosa, M Galván; Siegel, J; Solis, J

2009-11-09

We have used a low repetition rate (1 kHz), femtosecond laser amplifier in combination with a spatial light modulator (SLM) to write optical waveguides with controllable cross-section inside a phosphate glass sample. The SLM is used to induce a controllable amount of astigmatism in the beam wavefront while the beam ellipticity is controlled through the propagation distance from the SLM to the focusing optics of the writing set-up. The beam astigmatism leads to the formation of two separate disk-shaped foci lying in orthogonal planes. Additionally, the ellipticity has the effect of enabling control over the relative peak irradiances of the two foci, making it possible to bring the peak irradiance of one of them below the material transformation threshold. This allows producing a single waveguide with controllable cross-section. Numerical simulations of the irradiance distribution at the focal region under different beam shaping conditions are compared to in situ obtained experimental plasma emission images and structures produced inside the glass, leading to a very satisfactory agreement. Finally, guiding structures with controllable cross-section are successfully produced in the phosphate glass using this approach.

Measurement of the Raman scattering cross section of the breathing mode in KDP and DKDP crystals.

PubMed

Demos, Stavros G; Raman, Rajesh N; Yang, Steven T; Negres, Raluca A; Schaffers, Kathleen I; Henesian, Mark A

2011-10-10

The spontaneous Raman scattering cross sections of the main peaks (related to the A1 vibrational mode) in rapid and conventional grown potassium dihydrogen phosphate and deuterated crystals are measured at 532 nm, 355 nm, and 266 nm. The measurement involves the use of the Raman line of water centered at 3400 cm-1 as a reference to obtain relative values of the cross sections which are subsequently normalized against the known absolute value for water as a function of excitation wavelength. This measurement enables the estimation of the transverse stimulated Raman scattering gain of these nonlinear optical materials in various configurations suitable for frequency conversion and beam control in high-power, large-aperture laser systems.

A 184-year record of river meander migration from tree rings, aerial imagery, and cross sections

NASA Astrophysics Data System (ADS)

Schook, Derek M.; Rathburn, Sara L.; Friedman, Jonathan M.; Wolf, J. Marshall

2017-09-01

Channel migration is the primary mechanism of floodplain turnover in meandering rivers and is essential to the persistence of riparian ecosystems. Channel migration is driven by river flows, but short-term records cannot disentangle the effects of land use, flow diversion, past floods, and climate change. We used three data sets to quantify nearly two centuries of channel migration on the Powder River in Montana. The most precise data set came from channel cross sections measured an average of 21 times from 1975 to 2014. We then extended spatial and temporal scales of analysis using aerial photographs (1939-2013) and by aging plains cottonwoods along transects (1830-2014). Migration rates calculated from overlapping periods across data sets mostly revealed cross-method consistency. Data set integration revealed that migration rates have declined since peaking at 5 m/year in the two decades after the extreme 1923 flood (3000 m3/s). Averaged over the duration of each data set, cross section channel migration occurred at 0.81 m/year, compared to 1.52 m/year for the medium-length air photo record and 1.62 m/year for the lengthy cottonwood record. Powder River peak annual flows decreased by 48% (201 vs. 104 m3/s) after the largest flood of the post-1930 gaged record (930 m3/s in 1978). Declining peak discharges led to a 53% reduction in channel width and a 29% increase in sinuosity over the 1939-2013 air photo record. Changes in planform geometry and reductions in channel migration make calculations of floodplain turnover rates dependent on the period of analysis. We found that the intensively studied last four decades do not represent the past two centuries.

A 184-year record of river meander migration from tree rings, aerial imagery, and cross sections

USGS Publications Warehouse

Schook, Derek M.; Rathburn, Sara L.; Friedman, Jonathan M.; Wolf, J. Marshall

2017-01-01

Channel migration is the primary mechanism of floodplain turnover in meandering rivers and is essential to the persistence of riparian ecosystems. Channel migration is driven by river flows, but short-term records cannot disentangle the effects of land use, flow diversion, past floods, and climate change. We used three data sets to quantify nearly two centuries of channel migration on the Powder River in Montana. The most precise data set came from channel cross sections measured an average of 21 times from 1975 to 2014. We then extended spatial and temporal scales of analysis using aerial photographs (1939–2013) and by aging plains cottonwoods along transects (1830–2014). Migration rates calculated from overlapping periods across data sets mostly revealed cross-method consistency. Data set integration revealed that migration rates have declined since peaking at 5 m/year in the two decades after the extreme 1923 flood (3000 m3/s). Averaged over the duration of each data set, cross section channel migration occurred at 0.81 m/year, compared to 1.52 m/year for the medium-length air photo record and 1.62 m/year for the lengthy cottonwood record. Powder River peak annual flows decreased by 48% (201 vs. 104 m3/s) after the largest flood of the post-1930 gaged record (930 m3/s in 1978). Declining peak discharges led to a 53% reduction in channel width and a 29% increase in sinuosity over the 1939–2013 air photo record. Changes in planform geometry and reductions in channel migration make calculations of floodplain turnover rates dependent on the period of analysis. We found that the intensively studied last four decades do not represent the past two centuries

Photo-ionization cross-section of donor-related in (In,Ga)N/GaN core/shell under hydrostatic pressure and electric field effects

NASA Astrophysics Data System (ADS)

El Ghazi, Haddou; John Peter, A.

2017-04-01

Hydrogenic-like donor-impurity related self and induced polarizations, bending energy and photo-ionization cross section in spherical core/shell zinc blende (In,Ga)N/GaN are computed. Based on the variational approach and within effective-mass and one parabolic approximations, the calculations are made under finite potential barrier taking into account of the discontinuity of the effective-mass and the constant dielectric. The photo-ionization cross section is studied according to the photon incident energy considering the effects of hydrostatic pressure, applied electric field, structure's radius, impurity's position and indium composition in the core. It is obtained that the influences mentioned above lead to either blue shifts or redshifts of the resonant peak of the photo-ionization cross section spectrum. The unusual behavior related to the structure radius is discussed which is as a consequence of the finite potential confinement. We have shown that the photo-ionization cross section can be controlled with adjusting the internal and external factors. These properties can be useful for producing some device applications such as quantum dot infrared photodetectors.

Single- and Double-Strand Breaks of Dry DNA Exposed to Protons at Bragg-Peak Energies.

PubMed

Souici, Mounir; Khalil, Talat T; Muller, Dominique; Raffy, Quentin; Barillon, Rémi; Belafrites, Abdelfettah; Champion, Christophe; Fromm, Michel

2017-01-26

Ultrathin layers (<20 nm) of pBR322 plasmid DNA were deposited onto 2.5 μm thick polyester films and exposed to proton Bragg-peak energies (90-3000 keV) at various fluences. A quantitative analysis of radio-induced DNA damage is reported here in terms of single- and double-strand breaks (SSB and DSB, respectively). The corresponding yields as well as G-values and the cross sections exhibit fairly good agreement with the rare available data, stemming from close experimental conditions, namely, based on α particle irradiation. SSB/DSB rates appear to be linear when plotted against linear energy transfer (LET) in the whole energy range studied. All the data present a maximum in the 150-200 keV energy range; as for LET, it peaks at 90 keV. We also show that fragmentation starts to be significant for proton fluences greater than 1 × 10 11 cm -2 at the Bragg-peak energies. Finally, we determine the average proton track radial extension, r max , corresponding to an occupation probability of 100% DSB in the Bragg-peak region. The r max values determined are in excellent agreement with the radial extensions of proton tracks determined by simulation approaches in water. When plotted as a function of LET, both SSB and DSB cross sections bend back at high LETs.

Advantages of TOF-SIMS analysis of hydroxyapatite and fluorapatite in comparison with XRD, HR-TEM and FT-IR.

PubMed

Okazaki, Masayuki; Hirata, Isao; Matsumoto, Takuya; Takahashi, Junzo

2005-12-01

The chemical analysis of hydroxyapatite and fluorapatite was carried out using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Hydroxyapatite and fluorapatite were synthesized at 80 +/- 1 degrees C and pH 7.4 +/- 0.2. Fluorapatite was better crystallized, with its (300) reflection shifted to a slightly higher angle. High-resolution transmission electron microscopy clearly revealed a typical, regular hexagonal cross section perpendicular to the c-axis for fluorapatite and a flattened hexagonal cross section for hydroxyapatite. FT-IR spectra of fluorapatite confirmed the absence of OH absorption peak--which was seen in hydroxyapatite at about 3570 cm(-1). TOF-SIMS mass spectra showed a peak at 40 amu due to calcium. In addition, a peak at 19 amu due to fluorine could be clearly seen, although the intensities of PO, PO2, and PO3 were very low. It was confirmed that TOF-SIMS clearly showed the differences between positive and negative mass spectra of hydroxyapatite and fluorapatite, especially for F-. We concluded that TOF-SIMS exhibited distinct advantages compared with other methods of analysis.

α and 2 p 2 n emission in fast neutron-induced reactions on 60Ni

NASA Astrophysics Data System (ADS)

Fotiades, N.; Devlin, M.; Haight, R. C.; Nelson, R. O.; Kunieda, S.; Kawano, T.

2015-06-01

Background: The cross sections for populating the residual nucleus in the reaction ZAX(n,x) Z -2 A -4Y exhibit peaks as a function of incident neutron energy corresponding to the (n ,n'α ) reaction and, at higher energy, to the (n ,2 p 3 n ) reaction. The relative magnitudes of these peaks vary with the Z of the target nucleus. Purpose: Study fast neutron-induced reactions on 60Ni. Locate experimentally the nuclear charge region along the line of stability where the cross sections for α emission and for 2 p 2 n emission in fast neutron-induced reactions are comparable as a further test of reaction models. Methods: Data were taken by using the Germanium Array for Neutron-Induced Excitations. The broad-spectrum pulsed neutron beam of the Los Alamos Neutron Science Center's Weapons Neutron Research facility provided neutrons in the energy range from 1 to 250 MeV. The time-of-flight technique was used to determine the incident-neutron energies. Results: Absolute partial cross sections for production of seven discrete Fe γ rays populated in 60Ni (n ,α /2 p x n γ ) reactions with 2 ≤x ≤5 were measured for neutron energies 1 MeV

Low-energy and very-low energy total cross sections for electron collisions with N2

NASA Astrophysics Data System (ADS)

Kitajima, Masashi; Kishino, Takaya; Okumura, Takuma; Kobayashi, Naomasa; Sayama, Atsushi; Mori, Yuma; Hosaka, Kouichi; Odagiri, Takeshi; Hoshino, Masamitsu; Tanaka, Hiroshi

2017-06-01

Absolute grand total cross sections for electron scattering from N2 are obtained in the energy range from 20 eV down to 5 meV with very narrow electron energy width of 9 meV using the threshold-photoelectron source. Total cross sections obtained in the present study are compared with the previous experimentally obtained results. At the very-low energy region below 50 meV, the present total cross sections are somewhat smaller than those reported by the Aarhus group [S.V. Hoffmann et al., Rev. Sci. Instrum. 73, 4157 (2002)], which has been the only experimental work that provided the total cross sections in the very-low energy region. The energy positions of the peaks in the total cross sections due to the 2Πg shape resonance are obtained with higher accuracy, due to the improved uncertainty of the energy position in the present measurement compared to the previous works. The resonance structure in the total cross sections due to the Feshbach resonances of N2 at around 11.5 eV are also observed. Analysis of the resonant structure was carried out in order to determine the values of resonance width of Feshbach resonances of N2. Contribution to the Topical Issue: "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

Simulated peak flows and water-surface profiles for Scott Creek near Sylva, North Carolina

USGS Publications Warehouse

Pope, B.F.

1996-01-01

Peak flows were simulated for Scott Creek, just upstream from Sylva, in Jackson County, North Carolina, in order to provide Jackson County officials with information that can be used to improve preparation for and response to flash floods along the reach of Scott Creek that flows through Sylva. A U.S. Geological Survey rainfall-runoff model was calibrated using observed rainfall and streamflow data collected from March 1994 through September 1995. Standard errors for calibration were 34 percent for runoff volumes and 21 percent for peak flows. The calibrated model was used to simulate peak flows resulting from syn- thetic rainfall amounts of 1.0, 2.5, 5.0, and 7.5 inches in 24-hour periods. For each rainfall amount, peak flows were simulated under low-, moderate-, and high-antecedent soil-moisture conditions, represented by selected 3-month periods of daily rainfall and evaporation record from nearby climatic-data measuring stations. Simulated peak flows ranged from 89 to 10,100 cubic feet per second. Profiles of water-surface elevations for selected observed and simu- lated peak flows were computed for the reach of Scott Creek that flows through Sylva, North Carolina. The profiles were computed using the U.S. Army Corps of Engineers HEC-2 Water Surface Profiles computer program and channel cross-section data collected by the Tennessee Valley Authority. The stage-discharge relation for Scott Creek at the simulation site has changed since the collection of the cross-section data. These changes, however, are such that the water-surface profiles presented in this report likely overestimate the true water-surface elevations at the simulation site for a given peak flow

Deficits in Lower Limb Muscle Reflex Contraction Latency and Peak Force Are Associated With Impairments in Postural Control and Gross Motor Skills of Children With Developmental Coordination Disorder: A Cross-Sectional Study.

PubMed

Fong, Shirley S M; Ng, Shamay S M; Guo, X; Wang, Yuling; Chung, Raymond C K; Stat, Grad; Ki, W Y; Macfarlane, Duncan J

2015-10-01

This cross-sectional, exploratory study aimed to compare neuromuscular performance, balance and motor skills proficiencies of typically developing children and those with developmental coordination disorder (DCD) and to determine associations of these neuromuscular factors with balance and motor skills performances in children with DCD.One hundred thirty children with DCD and 117 typically developing children participated in the study. Medial hamstring and gastrocnemius muscle activation onset latencies in response to an unexpected posterior-to-anterior trunk perturbation were assessed by electromyography and accelerometer. Hamstring and gastrocnemius muscle peak force and time to peak force were quantified by dynamometer, and balance and motor skills performances were evaluated with the Movement Assessment Battery for Children (MABC).Independent t tests revealed that children with DCD had longer hamstring and gastrocnemius muscle activation onset latencies (P < 0.001) and lower isometric peak forces (P < 0.001), but not times to peak forces (P > 0.025), than the controls. Multiple regression analysis accounting for basic demographics showed that gastrocnemius peak force was independently associated with the MABC balance subscore and ball skills subscore, accounting for 5.7% (P = 0.003) and 8.5% (P = 0.001) of the variance, respectively. Gastrocnemius muscle activation onset latency also explained 11.4% (P < 0.001) of the variance in the MABC ball skills subscore.Children with DCD had delayed leg muscle activation onset times and lower isometric peak forces. Gastrocnemius peak force was associated with balance and ball skills performances, whereas timing of gastrocnemius muscle activation was a determinant of ball skill performance in the DCD population.

MODELING TIME DISPERSION DUE TO OPTICAL PATH LENGTH DIFFERENCES IN SCINTILLATION DETECTORS*

PubMed Central

Moses, W.W.; Choong, W.-S.; Derenzo, S.E.

2015-01-01

We characterize the nature of the time dispersion in scintillation detectors caused by path length differences of the scintillation photons as they travel from their generation point to the photodetector. Using Monte Carlo simulation, we find that the initial portion of the distribution (which is the only portion that affects the timing resolution) can usually be modeled by an exponential decay. The peak amplitude and decay time depend both on the geometry of the crystal, the position within the crystal that the scintillation light originates from, and the surface finish. In a rectangular parallelpiped LSO crystal with 3 mm × 3 mm cross section and polished surfaces, the decay time ranges from 10 ps (for interactions 1 mm from the photodetector) up to 80 ps (for interactions 50 mm from the photodetector). Over that same range of distances, the peak amplitude ranges from 100% (defined as the peak amplitude for interactions 1 mm from the photodetector) down to 4% for interactions 50 mm from the photodetector. Higher values for the decay time are obtained for rough surfaces, but the exact value depends on the simulation details. Estimates for the decay time and peak amplitude can be made for different cross section sizes via simple scaling arguments. PMID:25729464

Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors

DOE PAGES

Moses, W. W.; Choong, W. -S.; Derenzo, S. E.

2014-08-20

In this paper, we characterize the nature of the time dispersion in scintillation detectors caused by path length differences of the scintillation photons as they travel from their generation point to the photodetector. Using Monte Carlo simulation, we find that the initial portion of the distribution (which is the only portion that affects the timing resolution) can usually be modeled by an exponential decay. The peak amplitude and decay time depend both on the geometry of the crystal, the position within the crystal that the scintillation light originates from, and the surface finish. In a rectangular parallelpiped LSO crystal withmore » 3 mm × 3 mm cross section and polished surfaces, the decay time ranges from 10 ps (for interactions 1 mm from the photodetector) up to 80 ps (for interactions 50 mm from the photodetector). Over that same range of distances, the peak amplitude ranges from 100% (defined as the peak amplitude for interactions 1 mm from the photodetector) down to 4% for interactions 50 mm from the photodetector. Higher values for the decay time are obtained for rough surfaces, but the exact value depends on the simulation details. Finally, estimates for the decay time and peak amplitude can be made for different cross section sizes via simple scaling arguments.« less

Extreme Ultraviolet Emission Spectrum of CO_2 Induced by Electron Impact at 200 eV

NASA Technical Reports Server (NTRS)

Kanik, I.; Ajello, J. M.; James, G. K.

1993-01-01

We present the extreme ultraviolet (EUV) emission spectrum of CO_2 induced by electronimpact at 200 eV. There are 36 spectral features which are identified with a resolution of 0.5 nmover the wavelength range of 40 to 125 nm. Absolute emission cross sections were obtained for eachof these features. The EUV emission spectrum induced by electron impact consist of atomicmultiplets of CI,II and OI,II,III as well as CO and CO^+ molecular band systems produced bydissociative excitation. The CI (119.4 nm) multiplet is the strongest feature of CI with a peak crosssection of 3.61 x 10^(-19) cm^2 at 200 eV. The strongest feature of OI in the EUV spectrum is theOI (99.0 nm) multiplet with a peak cross section of 3.59 x 10^(-19) cm^2 at 200 eV.

Dissociative excitation of the N(+)(5S) state by electron impact on N2 - Excitation function and quenching

NASA Technical Reports Server (NTRS)

Erdman, P. W.; Zipf, E. C.

1986-01-01

Metastable N(+)(5S) ions were produced in the laboratory by dissociative excitation of N2 with energetic electrons. The resulting radiative decay of the N(+)(5S) state was observed with sufficient resolution to completely resolve the doublet from the nearby N2 molecular radiation. The excitation function was measured from threshold to 500 eV. The cross section peaks at a high electron energy and also exhibits a high threshold energy both of which are typical of dissociative excitation-ionization processes. This finding complicates the explanation of electron impact on N2 as the mechanism for the source of the 2145 A 'auroral mystery feature' by further increasing the required peak cross section. It is suggested that the apparent N(+)(5S) quenching in auroras may be an artifact due to the softening of the electron energy spectrum in the auroral E region.

Photodissociation of the CH3Cl/+/ and N2O/+/ cations.

NASA Technical Reports Server (NTRS)

Dunbar, R. C.

1971-01-01

Use of the ion cyclotron resonance (icr) technique to observe the photodissociation of the cations CH3Cl(+) and N2O(+) in the gas phase. Ions were trapped in the icr cell for periods of the order of seconds, which permitted the photodissociation process to be observed with wavelength-selected light. A cyclotron resonance ejection technique was employed to show that CH3Cl(+) ions were being dissociated rather than the CH3ClH(+) ions which were also present. The photodissociation cross section for N2O(+) was found to be without strong wavelength dependence between 4000 and 6500 A. The cross section for CH3Cl(+) showed a large peak at 3150 A. Possible assignments of this peak are considered, and it is suggested that a photodissociation occurs through an ion excitation involving a change in occupation of the bonding or antibonding orbitals of the C-Cl bond.

Embryonic stem cells improve skeletal muscle recovery after extreme atrophy in mice.

PubMed

Artioli, Guilherme Giannini; De Oliveira Silvestre, João Guilherme; Guilherme, João Paulo Limongi França; Baptista, Igor Luchini; Ramos, Gracielle Vieira; Da Silva, Willian José; Miyabara, Elen Haruka; Moriscot, Anselmo Sigari

2015-03-01

We injected embryonic stem cells into mouse tibialis anterior muscles subjected to botulinum toxin injections as a model for reversible neurogenic atrophy. Muscles were exposed to botulinum toxin for 4 weeks and allowed to recover for up to 6 weeks. At the onset of recovery, a single muscle injection of embryonic stem cells was administered. The myofiber cross-sectional area, single twitch force, peak tetanic force, time-to-peak force, and half-relaxation time were determined. Although the stem cell injection did not affect the myofiber cross-sectional area gain in recovering muscles, most functional parameters improved significantly compared with those of recovering muscles that did not receive the stem cell injection. Muscle function recovery was accelerated by embryonic stem cell delivery in this durable neurogenic atrophy model. We conclude that stem cells should be considered a potential therapeutic tool for recovery after extreme skeletal muscle atrophy. © 2014 Wiley Periodicals, Inc.

Absorption spectrum and absorption cross sections of the 2ν1 band of HO2 between 20 and 760 Torr air in the range 6636 and 6639 cm-1

NASA Astrophysics Data System (ADS)

Assaf, Emmanuel; Liu, Lu; Schoemaecker, Coralie; Fittschen, Christa

2018-05-01

The absorption spectrum of HO2 radicals has been measured in the range 6636-6639 cm-1 at several pressures between 20 and 760 Torr of air. Absolute absorption cross sections of the strongest line at around 6638.2 cm-1 have been determined from kinetic measurements, taking advantage of the well known rate constant of the self-reaction. Peak absorption cross sections of 22.6, 19.5, 14.4, 7.88, 5.12 and 3.23 × 10-20 cm2 were obtained at 20, 50, 100, 200, 400 and 760 Torr, respectively. By fitting these data, an empirical expression has been obtained for the absorption cross section of HO2 in the range 20-760 Torr air: σ6638.2cm-1 = 1.18 × 10-20 + (2.64 × 10-19 × (1-exp (-63.1/p (Torr))) cm2.

Estimating Infection Attack Rates and Severity in Real Time during an Influenza Pandemic: Analysis of Serial Cross-Sectional Serologic Surveillance Data

PubMed Central

Wu, Joseph T.; Ho, Andrew; Ma, Edward S. K.; Lee, Cheuk Kwong; Chu, Daniel K. W.; Ho, Po-Lai; Hung, Ivan F. N.; Ho, Lai Ming; Lin, Che Kit; Tsang, Thomas; Lo, Su-Vui; Lau, Yu-Lung; Leung, Gabriel M.

2011-01-01

Background In an emerging influenza pandemic, estimating severity (the probability of a severe outcome, such as hospitalization, if infected) is a public health priority. As many influenza infections are subclinical, sero-surveillance is needed to allow reliable real-time estimates of infection attack rate (IAR) and severity. Methods and Findings We tested 14,766 sera collected during the first wave of the 2009 pandemic in Hong Kong using viral microneutralization. We estimated IAR and infection-hospitalization probability (IHP) from the serial cross-sectional serologic data and hospitalization data. Had our serologic data been available weekly in real time, we would have obtained reliable IHP estimates 1 wk after, 1–2 wk before, and 3 wk after epidemic peak for individuals aged 5–14 y, 15–29 y, and 30–59 y. The ratio of IAR to pre-existing seroprevalence, which decreased with age, was a major determinant for the timeliness of reliable estimates. If we began sero-surveillance 3 wk after community transmission was confirmed, with 150, 350, and 500 specimens per week for individuals aged 5–14 y, 15–19 y, and 20–29 y, respectively, we would have obtained reliable IHP estimates for these age groups 4 wk before the peak. For 30–59 y olds, even 800 specimens per week would not have generated reliable estimates until the peak because the ratio of IAR to pre-existing seroprevalence for this age group was low. The performance of serial cross-sectional sero-surveillance substantially deteriorates if test specificity is not near 100% or pre-existing seroprevalence is not near zero. These potential limitations could be mitigated by choosing a higher titer cutoff for seropositivity. If the epidemic doubling time is longer than 6 d, then serial cross-sectional sero-surveillance with 300 specimens per week would yield reliable estimates when IAR reaches around 6%–10%. Conclusions Serial cross-sectional serologic data together with clinical surveillance data can allow reliable real-time estimates of IAR and severity in an emerging pandemic. Sero-surveillance for pandemics should be considered. Please see later in the article for the Editors' Summary PMID:21990967

Biomechanical Factors Associated With Jump Height: A Comparison of Cross-Sectional and Pre-to-Posttraining Change Findings.

PubMed

Marshall, Brendan M; Moran, Kieran A

2015-12-01

Previous studies investigating the biomechanical factors associated with maximal countermovement jump height have typically used cross-sectional data. An alternative but less common approach is to use pre-to-posttraining change data, where the relationship between an improvement in jump height and a change in a factor is examined more directly. Our study compared the findings of these approaches. Such an evaluation is necessary because cross-sectional studies are currently a primary source of information for coaches when examining what factors to train to enhance performance. The countermovement jump of 44 males was analyzed before and after an 8-week training intervention. Correlations with jump height were calculated using both cross-sectional (pretraining data only) and pre-to-posttraining change data. Eight factors identified in the cross-sectional analysis were not significantly correlated with a change in jump height in the pre-to-post analysis. Additionally, only 6 of 11 factors identified in the pre-to-post analysis were identified in the cross-sectional analysis. These findings imply that (a) not all factors identified in a cross-sectional analysis may be critical to jump height improvement and (b) cross-sectional analyses alone may not provide an insight into all of the potential factors to train to enhance jump height. Coaches must be aware of these limitations when examining cross-sectional studies to identify factors to train to enhance jump ability. Additional findings highlight that although exercises prescribed to improve jump height should aim to enhance concentric power production at all joints, a particular emphasis on enhancing hip joint peak power may be warranted.

Measurements of differential and double-differential Drell–Yan cross sections in proton–proton collisions at √s = 8 TeV

DOE PAGES

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; ...

2015-04-09

Measurements of the differential and double-differential Drell–Yan cross sections in the dielectron and dimuon channels are presented. They are based on proton–proton collision data at √s = 8TeV recorded with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7fb –1. The measured inclusive cross section in the Z peak region (60–120GeV), obtained from the combination of the dielectron and dimuon channels, is 1138 ± 8 (exp) ± 25 (theo) ± 30 (lumi)\\,pb, where the statistical uncertainty is negligible. The differential cross section dσ/dm in the dilepton mass range 15–2000GeV is measured and corrected to themore » full phase space. The double-differential cross section d 2σ/dmd|y| is also measured over the mass range 20 to 1500GeV and absolute dilepton rapidity from 0 to 2.4. In addition, the ratios of the normalized differential cross sections measured at √s = 7 and 8TeV are presented. These measurements are compared to the predictions of perturbative QCD at next-to-leading and next-to-next-to-leading (NNLO) orders using various sets of parton distribution functions (PDFs). The results agree with the NNLO theoretical predictions computed with FEWZ 3.1 using the CT10 NNLO and NNPDF2.1 NNLO PDFs. Furthermore, the measured double-differential cross section and ratio of normalized differential cross sections are sufficiently precise to constrain the proton PDFs.« less

Radiation characteristics and effective optical properties of dumbbell-shaped cyanobacterium Synechocystis sp.

NASA Astrophysics Data System (ADS)

Heng, Ri-Liang; Pilon, Laurent

2016-05-01

This study presents experimental measurements of the radiation characteristics of unicellular freshwater cyanobacterium Synechocystis sp. during their exponential growth in F medium. Their scattering phase function at 633 nm average spectral absorption and scattering cross-sections between 400 and 750 nm were measured. In addition, an inverse method was used for retrieving the spectral effective complex index of refraction of overlapping or touching bispheres and quadspheres from their absorption and scattering cross-sections. The inverse method combines a genetic algorithm and a forward model based on Lorenz-Mie theory, treating bispheres and quadspheres as projected area and volume-equivalent coated spheres. The inverse method was successfully validated with numerically predicted average absorption and scattering cross-sections of suspensions consisting of bispheres and quadspheres, with realistic size distributions, using the T-matrix method. It was able to retrieve the monomers' complex index of refraction with size parameter up to 11, relative refraction index less than 1.3, and absorption index less than 0.1. Then, the inverse method was applied to retrieve the effective spectral complex index of refraction of Synechocystis sp. approximated as randomly oriented aggregates consisting of two overlapping homogeneous spheres. Both the measured absorption cross-section and the retrieved absorption index featured peaks at 435 and 676 nm corresponding to chlorophyll a, a peak at 625 nm corresponding to phycocyanin, and a shoulder around 485 nm corresponding to carotenoids. These results can be used to optimize and control light transfer in photobioreactors. The inverse method and the equivalent coated sphere model could be applied to other optically soft particles of similar morphologies.

A Thermoelastic Damping Model for the Cone Microcantilever Resonator with Circular Cross-section

NASA Astrophysics Data System (ADS)

Li, Pu; Zhou, Hongyue

2017-07-01

Microbeams with variable cross-section have been applied in Microelectromechanical Systems (MEMS) resonators. Quality factor (Q-factor) is an important factor evaluating the performance of MEMS resonators, and high Q-factor stands for the excellent performance. Thermoelastic damping (TED), which has been verified as a fundamental energy lost mechanism for microresonators, determines the upper limit of Q-factor. TED can be calculated by the Zener’s model and Lifshits and Roukes (LR) model. However, for microbeam resonators with variable cross-sections, these two models become invalid in some cases. In this work, we derived the TED model for cone microcantilever with circular cross-section that is a representative non-uniform microbeam. The comparison of results obtained by the present model and Finite Element Method (FEM) model proves that the present model is valid for predicting TED value for cone microcantilever with circular cross-section. The results suggest that the first-order natural frequencies and TED values of cone microcantilever are larger than those of uniform microbeam for large aspect ratios (l/r 0). In addition, the Debye peak value of a uniform microcantilever is equal to 0.5ΔE, while that of cone microcantilever is about 0.438ΔE.

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint.

PubMed

Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan Rt

2017-01-01

Data about a muscle's fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function.

Electron Collision Processes with Carbon Dioxide: Resolving Long-Standing Paradoxes

NASA Astrophysics Data System (ADS)

Rescigno, T. N.; Haxton, D. J.; McCurdy, C. W.

2012-10-01

The principal features of low-energy electron-CO2 collisions have been known and studied for over forty years. The scattering is characterized by a rapid rise in the total cross section below 1 eV, anomalous threshold behavior for excitation of symmetric stretch and bending vibrational modes, resonant vibrational excitation near 4 eV with weak ``boomerang'' structure in the excitation cross sections and dissociative electron attachment cross sections leading to CO + O^- which peak near 4 eV and 8 eV and have angular distributions which show large deviations from axial recoil. The nuclear dynamics associated with all these features is intrinsically polyatomic in nature and cannot be described with one-dimensional models. The present study provides a consistent description of all these phenomena and resolves a number long-standing paradoxes and misconceptions found in the extant literature.

Total cross section for the γd-->π-pp reaction between 380 and 840 MeV

NASA Astrophysics Data System (ADS)

Asai, M.; Endo, I.; Harada, M.; Kasai, S.; Niki, K.; Sumi, Y.; Kato, S.; Maruyama, K.; Murata, Y.; Muto, M.; Yoshida, K.; Iwatani, K.; Hasai, H.; Ito, H.; Maki, T.; Rangacharyulu, C.; Shimizu, H.; Wada, Y.

1990-09-01

The total cross section for the γd-->π-pp reaction has been measured for incident photon energies from 380 to 840 MeV in steps of 10 MeV, with the best energy resolution attained so far. A large-acceptance detector was used to observe the reaction products. Overall uncertainties in the deduced cross sections are less than 9% (~4% statistical and ~8% systematic). The results are in excellent agreement with previous bubble chamber measurements and do not show any statistically significant structure which can be interpreted as evidence for the formation of dibaryon resonances. An upper limit at 95% confidence level of σpeakΓ<230 μb MeV is obtained for a resonance in the vicinity of photon energy 700 MeV (mass~2490 MeV).

Vitamin D status and V[combining dot above]O2peak during a skate treadmill graded exercise test in competitive ice hockey players.

PubMed

Fitzgerald, John S; Peterson, Ben J; Warpeha, Joseph M; Wilson, Patrick B; Rhodes, Greg S; Ingraham, Stacy J

2014-11-01

Vitamin D status has been associated with cardiorespiratory fitness (CRF) in cross-sectional investigations in the general population. Data characterizing the association between 25-hydroxyvitamin D (25(OH)D) concentration and CRF in athletes are lacking. Junior and collegiate ice hockey players were recruited from the Minneapolis, MN (44.9° N), area during the off-season period (May 16-June 28). The purpose of this study was to examine the cross-sectional association between 25(OH)D concentration and CRF in a sample population of competitive ice hockey players. Circulating 25(OH)D level was assessed from a capillary blood sample analyzed using liquid chromatography-tandem mass spectrometry. V[Combining Dot Above]O2peak during a skate treadmill graded exercise test (GXT) was used to assess CRF. Data on both 25(OH)D concentration and V[Combining Dot Above]O2peak were available for 52 athletes. Insufficient 25(OH)D concentrations were found in 37.7% of the athletes (<32 ng·ml). Vitamin D status was not significantly associated with any physiological or physical parameter during the skate treadmill GXT.

Neutron capture cross sections of 69Ga and 71Ga at 25 keV and Epeak = 90 keV

NASA Astrophysics Data System (ADS)

Göbel, Kathrin; Beinrucker, Clemens; Erbacher, Philipp; Fiebiger, Stefan; Fonseca, Micaela; Heftrich, Michael; Heftrich, Tanja; Käppeler, Franz; Krása, Antonin; Lederer-Woods, Claudia; Plag, Ralf; Plompen, Arjan; Reifarth, René; Schmidt, Stefan; Sonnabend, Kerstin; Weigand, Mario

2017-09-01

We measured the neutron capture cross sections of 69Ga and 71Ga for a quasi-stellar spectrum at kBT = 25 keV and a spectrum with a peak energy at 90 keV by the activation technique at the Joint Research Centre (JRC) in Geel, Belgium. Protons were provided by an electrostatic Van de Graaff accelerator to produce neutrons via the reaction 7Li(p,n). The produced activity was measured via the γ emission of the product nuclei by high-purity germanium detectors. We present preliminary results.

Effective gain measurements in chromium-doped forsterite

NASA Technical Reports Server (NTRS)

Petricevic, V.; Seas, A.; Alfano, R. R.

1991-01-01

Effective gain cross section in tetravalent chromium-doped forsterite laser crystal was measured over the 1180-1330 nm spectral range. The experiment was performed using two collinear laser beams in a pump-and-probe arrangement. The peak-gain cross section from this measurement is estimated to be 1.9 x 10 to the -19th sq cm at 1215 nm, which is comparable to the value of about 2 x 10 to the -19th sq cm predicted by fluorescence linewidth and lifetime measurements. These results indicate that excited-state absorption is not a major loss mechanism in tetravalent chromium-doped forsterite.

Tectonic overpressure may reconcile the structural and petrological records of the Adula nappe (Central Alps)

NASA Astrophysics Data System (ADS)

Pleuger, Jan; Podladchikov, Yuri

2014-05-01

The Penninic Alps are the result of progressive underthrusting of oceanic and continental domains below the Adriatic microplate. Situated in the internal part of the Alpine orogen, they expose basement and thinned cover nappes which have been metamorphosed to variable degree, among them several units which were subjected to ultrahigh-pressure metamorphism. Due to the more or less strong nappe-internal deformation of these units, cross sections through the Penninic Alps cannot be restored kinematically by area or line balancing techniques. Instead, such restorations attempt to consistently reconcile geochronological and structural data and petrological pressure-temperature estimates. Pressure data are usually converted into depth assuming that they were lithostatic which puts the ultrahigh-pressure units to subcrustal depths. Tectonic exhumation of a unit from such a depth by whatever mechanism requires a large-scale normal fault with several tens of kilometres of displacement in the hanging wall of the unit. However, for all Penninic ultrahigh-pressure units (Dora Maira unit, Zermatt-Saas zone, Monviso unit, Adula-Cima Lunga nappe), the oldest mappable post-peak-pressure structures are related to top-to-the-foreland shearing, i.e. thrusting. There are two potential solutions to this dilemma. The first one is that either the exhumation was indeed accommodated by a large-scale normal fault which became completely overprinted during later deformational stages. The other one is that peak pressures were not lithostatic. To our knowledge, the first solution is applied to all kinematic models of the Alps so far. In order to explore the feasibility of the second solution, we performed a purely structural restoration of the NFP20-East cross section without lithostatic pressure-to-depth-conversions. This cross-section comprises the ultrahigh-pressure Adula nappe (up to ca. 30 kbar) and relies on quantitative strain data from the overlying units. The result shows that, in accordance with the structural record, the Adula nappe can be restored to maximum depths of up to ca. 60 km. For individual points of the Adula nappe in the restored cross section, corresponding to the sporadic occurences of (ultra)high-pressure rocks, lithostatic pressures are exceeded by petrological peak-pressure data by about 40% to 80%. Such amounts of tectonic overpressure are within the limits of theoretical considerations and numerical modelling results. For the other units comprised in the cross section, and for subsequent tectono-metamorphic stages of the Adula nappe, negligible amounts of overpressure (around 10%) are determined from the restoration. We conclude that (1) the NFP20-East cross section can be kinematically restored by using only structural data, (2) the dilemma mentioned above can be solved by admitting realisting amounts of tectonic overpressure, and (3) significant amounts of overpressure were established only locally and episodically.

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

MIchael A. Pope

Six early cores of the MASURCA R-Z program were modeled using ERANOS 2.1. These cores were designed such that their neutron spectra would be similar to that of an oxide-fueled sodium-cooled fast reactor, some containing enriched uranium and others containing depleted uranium and plutonium. Effects of modeling assumptions and solution methods both in ECCO lattice calculations and in BISTRO Sn flux solutions were evaluated using JEFF-3.1 cross-section libraries. Reactivity effects of differences between JEFF-3.1 and ENDF/B-VI.8 were also quantified using perturbation theory analysis. The most important nuclide with respect to reactivity differences between cross-section libraries was 23Na, primarily a resultmore » of differences in the angular dependence of elastic scattering which is more forward-peaked in ENDF/B-VI.8 than in JEFF-3.1. Differences in 23Na inelastic scattering cross-sections between libraries also generated significant differences in reactivity, more due to the differences in magnitude of the cross-sections than the angular dependence. The nuclide 238U was also found to be important with regard to reactivity differences between the two libraries mostly due to a large effect of inelastic scattering differences and two smaller effects of elastic scattering and fission cross-sections. In the cores which contained plutonium, 239Pu fission cross-section differences contributed significantly to the reactivity differences between libraries.« less

Apparatus and Method for Measuring Strain in Optical Fibers using Rayleigh Scatter

NASA Technical Reports Server (NTRS)

Froggatt, Mark E. (Inventor); Moore, Jason P. (Inventor)

2003-01-01

An apparatus and method for measuring strain in an optical fiber using the spectral shift of Rayleigh scattered light. The interference pattern produced by an air gap reflector and backscattered radiation is measured. Using Fourier Transforms, the spectrum of any section of fiber can be extracted. Cross correlation with an unstrained measurement produces a correlation peak. The location of the correlation peak indicates the strain level in the selected portion of optical fiber.

Angular Distributions of Differential Electron Capture Cross Sections in Collisions Between Low-Velocity Highly-Charged Ions and Neutral Targets.

NASA Astrophysics Data System (ADS)

Waggoner, William Tracy

1990-01-01

Experimental capture cross sections d sigma / dtheta versus theta , are presented for various ions incident on neutral targets. First, distributions are presented for Ar ^{rm 8+} ions incident on H_{rm 2}, D _{rm 2}, and Ar targets. Energy gain studies indicate that capture occurs to primarily a 5d,f final state of Ar^{rm 7+} with some contributions from transfer ionization (T.I.) channels. Angular distribution spectra for all three targets are similar, with spectra having a main peak located at forward angles which is attributed to single capture events, and a secondary structure occurring at large angles which is attributed to T.I. contributions. A series of Ar^{rm 8+} on Ar spectra were collected using a retarding grid system as a low resolution energy spectrometer to resolve single capture events from T.I. events. The resulting single capture and T.I. angular distributions are presented. Results are discussed in terms of a classical deflection function employing a simple two state curve crossing model. Angular distributions for electron capture from He by C, N, O, F, and Ne ions with charge states from 5 ^+-8^+ are presented for projectile energies between 1.2 and 2.0 kV. Distributions for the same charge state but different ion species are simlar, but not identical with distributions for the 5 ^+ and 7^+ ions being strongly forward peaked, the 6^+ distributions are much less forward peaked with the O^{6+} distributions showing structure, the Ne^{8+} ion distribution appears to be an intermediate case between forward peaking and large angle scattering. These results are discussed in terms of classical deflection functions which utilize two state Coulomb diabatic curve crossing models. Finally, angular distributions are presented for electron capture from He by Ar^{rm 6+} ions at energies between 1287 eV and 296 eV. At large projectile energies the distribution is broad. As the energy decreases below 523 eV, distributions shift to forward angles with a second peak appearing outside the Coulomb angle, theta_{c} = Q/2E, which continues to grow in magnitude as the projectile energy decreases further. Results are compared with a model calculation employing a two state diabatic Coulomb curve crossing model and the classical deflection function.

High temperature infrared absorption cross sections of methane near 3.4 µm in Ar and CO 2 mixtures

DOE PAGES

Koroglu, Batikan; Neupane, Sneha; Pryor, Owen; ...

2017-11-04

In this study, the absorption cross-sections of CH 4 at two wavelengths in the mid-IR region: λ peak = 3403.4 nm and λ valley = 3403.7 nm were measured. Data were taken using three different compositions of non-reactive gas mixtures comprising CH 4/Ar/CO 2 between 700 < T < 2000 K and 0.1 < P < 1.5 atm in a shock tube utilizing a continuous-wave distributed-feedback quantum cascade laser. Also, broadband room temperature methane cross section measurements were performed using a Fourier transform infrared spectrometer and the cascade laser to gain a better insight into the changes of the linemore » shapes in various bath gasses (Ar, CO 2, and N 2). An application of the high-temperature cross-section data was demonstrated to determine the concentration of methane during oxy-methane combustion in a mixture of CO 2, O 2, and Ar. Lastly, current measurements will be valuable addition to the spectroscopy database for methane- an important fuel used for power generation and heating around the world.« less

Photodissociation spectroscopy of the dysprosium monochloride molecular ion

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

Dunning, Alexander, E-mail: alexander.dunning@gmail.com; Schowalter, Steven J.; Puri, Prateek

2015-09-28

We have performed a combined experimental and theoretical study of the photodissociation cross section of the molecular ion DyCl{sup +}. The photodissociation cross section for the photon energy range 35 500 cm{sup −1} to 47 500 cm{sup −1} is measured using an integrated ion trap and time-of-flight mass spectrometer; we observe a broad, asymmetric profile that is peaked near 43 000 cm{sup −1}. The theoretical cross section is determined from electronic potentials and transition dipole moments calculated using the relativistic configuration-interaction valence-bond and coupled-cluster methods. The electronic structure of DyCl{sup +} is extremely complex due to the presence of multiple open electronic shells,more » including the 4f{sup 10} configuration. The molecule has nine attractive potentials with ionically bonded electrons and 99 repulsive potentials dissociating to a ground state Dy{sup +} ion and Cl atom. We explain the lack of symmetry in the cross section as due to multiple contributions from one-electron-dominated transitions between the vibrational ground state and several resolved repulsive excited states.« less

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Spectroscopy of Pionic Atoms in 122Sn (d, 3He) Reaction and Angular Dependence of the Formation Cross Sections

NASA Astrophysics Data System (ADS)

Nishi, T.; Itahashi, K.; Berg, G. P. A.; Fujioka, H.; Fukuda, N.; Fukunishi, N.; Geissel, H.; Hayano, R. S.; Hirenzaki, S.; Ichikawa, K.; Ikeno, N.; Inabe, N.; Itoh, S.; Iwasaki, M.; Kameda, D.; Kawase, S.; Kubo, T.; Kusaka, K.; Matsubara, H.; Michimasa, S.; Miki, K.; Mishima, G.; Miya, H.; Nagahiro, H.; Nakamura, M.; Noji, S.; Okochi, K.; Ota, S.; Sakamoto, N.; Suzuki, K.; Takeda, H.; Tanaka, Y. K.; Todoroki, K.; Tsukada, K.; Uesaka, T.; Watanabe, Y. N.; Weick, H.; Yamakami, H.; Yoshida, K.; piAF Collaboration

2018-04-01

We observed the atomic 1 s and 2 p states of π- bound to 121Sn nuclei as distinct peak structures in the missing mass spectra of the 122Sn(d ,3He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2 p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1 s state.

Resonant vibrational-excitation cross sections and rate constants for low-energy electron scattering by molecular oxygen

NASA Astrophysics Data System (ADS)

Laporta, V.; Celiberto, R.; Tennyson, J.

2013-04-01

Resonant vibrational-excitation cross sections and rate constants for electron scattering by molecular oxygen are presented. Transitions between all 42 vibrational levels of O_2({X}\\, ^3\\Sigma_g^{-}) are considered. Molecular rotations are parametrized by the rotational quantum number J, which is considered in the range 1-151. The lowest four resonant states of O_2^- , 2Πg, 2Πu, ^4\\Sigma_u^- and ^2\\Sigma_u^- are taken into account. The calculations are performed using the fixed-nuclei R-matrix approach to determine the resonance positions and widths, and the boomerang model to characterize the nuclei motion. Two energy regions below and above 4 eV are investigated: the first one is characterized by sharp structures in the cross section and the second by a broad resonance peaked at 10 eV. The computed cross sections are compared with theoretical and experimental results available in the literature for both energy regions, and are made available for use by modelers. The effect of including rotational motion is found to be non-negligible.

High temperature infrared absorption cross sections of methane near 3.4 µm in Ar and CO 2 mixtures

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

Koroglu, Batikan; Neupane, Sneha; Pryor, Owen

In this study, the absorption cross-sections of CH 4 at two wavelengths in the mid-IR region: λ peak = 3403.4 nm and λ valley = 3403.7 nm were measured. Data were taken using three different compositions of non-reactive gas mixtures comprising CH 4/Ar/CO 2 between 700 < T < 2000 K and 0.1 < P < 1.5 atm in a shock tube utilizing a continuous-wave distributed-feedback quantum cascade laser. Also, broadband room temperature methane cross section measurements were performed using a Fourier transform infrared spectrometer and the cascade laser to gain a better insight into the changes of the linemore » shapes in various bath gasses (Ar, CO 2, and N 2). An application of the high-temperature cross-section data was demonstrated to determine the concentration of methane during oxy-methane combustion in a mixture of CO 2, O 2, and Ar. Lastly, current measurements will be valuable addition to the spectroscopy database for methane- an important fuel used for power generation and heating around the world.« less

High temperature infrared absorption cross sections of methane near 3.4 μm in Ar and CO2 mixtures

NASA Astrophysics Data System (ADS)

Koroglu, Batikan; Neupane, Sneha; Pryor, Owen; Peale, Robert E.; Vasu, Subith S.

2018-02-01

The absorption cross-sections of CH4 at two wavelengths in the mid-IR region: λpeak = 3403.4 nm and λvalley = 3403.7 nm were measured. Data were taken using three different compositions of non-reactive gas mixtures comprising CH4/Ar/CO2 between 700 < T < 2000 K and 0.1 < P < 1.5 atm in a shock tube utilizing a continuous-wave distributed-feedback quantum cascade laser. Also, broadband room temperature methane cross section measurements were performed using a Fourier transform infrared spectrometer and the cascade laser to gain a better insight into the changes of the line shapes in various bath gasses (Ar, CO2, and N2). An application of the high-temperature cross-section data was demonstrated to determine the concentration of methane during oxy-methane combustion in a mixture of CO2, O2, and Ar. Current measurements will be valuable addition to the spectroscopy database for methane- an important fuel used for power generation and heating around the world.

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

NASA Astrophysics Data System (ADS)

Dvali, Gia; Gußmann, Alexander

2016-12-01

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

Kinetic-Energy Distribution of D(2p) Atoms from Analysis of the D Lyman-Alpha Line Profile

NASA Technical Reports Server (NTRS)

Ciocca, M.; Ajello, Joseph M.; Liu, Xianming; Maki, Justin

1997-01-01

The kinetic-energy distribution of D(2p) atoms resulting from electron-impact dissociation of D2 has been measured. A high-resolution vacuum ultraviolet spectrometer was employed for the first measurement of the D Lyman-alpha (D L(alpha)) emission line profiles at 20- and 100-eV excitation energies. Analysis of the deconvoluted line profile of D L(alpha) at 100 eV reveals the existence of a narrow line central peak of 29+/-2 mA full width at half maximum and a broad pedestal wing structure about 190 mA wide. The wings of the line can be used to determine the fast atom distribution. The wings of D L(alpha) arise from dissociative excitation of a series of doubly excited states that cross the Franck-Condon region between 23 and 40 eV. The fast atom distribution at 100-eV electron impact energy spans the energy range from 1 to 10 eV with a peak value near 6 eV. Slow D(2p) atoms characterized by a distribution function with peak energy near 100 meV produce the central peak profile, which is nearly independent of the impact energy. The deconvoluted line profiles of the central peak at 20 eV for dissociative excitation of D2 and H2 are fitted with an analytical function for use in calibration of space flight instrumentation equipped with a D/H absorption cell. The kinetic-energy and line profile results are compared to similar measurements for H2. The absolute cross sections for the line center (slow atoms) and wings (fast atoms) and total emission line profile were measured from threshold to 400 eV. Analytical model coefficients are given for the energy dependence of the measured slow atom cross section.

Extracting biomolecule collision cross sections from the high-resolution FT-ICR mass spectral linewidths.

PubMed

Jiang, Ting; Chen, Yu; Mao, Lu; Marshall, Alan G; Xu, Wei

2016-01-14

It is known that the ion collision cross section (CCS) may be calculated from the linewidth of a Fourier transform ion cyclotron resonance (FT-ICR) mass spectral peak at elevated pressure (e.g., ∼10(-6) Torr). However, the high mass resolution of FT-ICR is sacrificed in those experiments due to high buffer gas pressure. In this study, we describe a linewidth correction method to eliminate the windowing-induced peak broadening effect. Together with the energetic ion-neutral collision model previously developed by our group, this method enables the extraction of CCSs of biomolecules from high-resolution FT-ICR mass spectral linewidths, obtained at a typical operating buffer gas pressure of modern FT-ICR instruments (∼10(-10) Torr). CCS values of peptides including MRFA, angiotensin I, and bradykinin measured by the proposed method agree well with ion mobility measurements, and the unfolding of protein ions (ubiquitin) at higher charge states is also observed.

Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction.

PubMed

Ahn, Ick Keun; Kim, You Lim; Bae, Young-Hyeon; Lee, Suk Min

2015-01-01

Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles.

High resolution absorption cross sections for the A2Pi-X2Pi system of ClO

NASA Technical Reports Server (NTRS)

Wine, P. H.; Ravishankara, A. R.; Philen, D. L.; Davis, D. D.; Watson, R. T.

1977-01-01

High-resolution ultraviolet absorption cross-sections for the ClO molecule are obtained, with the aim of facilitating studies of ozone depletion resulting from the injection of chlorofluorocarbons into the atmosphere. The spectroscopic analysis, which involves a frequency-doubled tunable dye laser with a bandwidth of 0.015 A, is described. Studies of the rotational lines of the ClO A 2Pi 3/2-X2Pi 3/2 9-10 band were conducted. Peak cross-sections for the P and R lines of the 9-0 band are found to be 10.0, 9.6, 8.6, 10.6, 10.3, and 9.2 times ten to the negative seventeenth power cm squared, with estimated accuracy of plus or minus 25%. Problems in distinguishing between Cl-35 and Cl-37 absorption are also considered.

Systematic measurement of double-differential neutron production cross sections for deuteron-induced reactions at an incident energy of 102 MeV

NASA Astrophysics Data System (ADS)

Araki, Shouhei; Watanabe, Yukinobu; Kitajima, Mizuki; Sadamatsu, Hiroki; Nakano, Keita; Kin, Tadahiro; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki; Yashima, Hiroshi; Shima, Tatsushi

2017-01-01

Double-differential neutron production cross sections (DDXs) for deuteron-induced reactions on Li, Be, C, Al, Cu, and Nb at 102 MeV were measured at forward angles ≤25° by means of a time of flight (TOF) method with NE213 liquid organic scintillators at the Research Center of Nuclear Physics (RCNP), Osaka University. The experimental DDXs and energy-integrated cross sections were compared with TENDL-2015 data and Particle and Heavy Ion Transport code System (PHITS) calculation using a combination of the KUROTAMA model, the Liege Intra-Nuclear Cascade model, and the generalized evaporation model. The PHITS calculation showed better agreement with the experimental results than TENDL-2015 for all target nuclei, although the shape of the broad peak around 50 MeV was not satisfactorily reproduced by the PHITS calculation.

X-ray production cross sections at incident photon energies across the M{sub i} (i=1-5) edges of {sub 90}Th

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

Kaur, Rajnish; Shehla,; Kumar, Anil

2015-08-28

The X-ray production cross sections for the M{sub k} (k= ξ, δ, α, β, ζ, γ, m{sub 1}, m{sub 2}) groups of X-rays have been evaluated at incident photon energies across the M{sub i} (i =1-5) edges of {sub 90}Th using the relativistic Hartree-Fock-Slater model based photoionisation cross sections and recently reported values of the M-shell X-ray emission rates, fluorescence and Coster Kronig yields. Further, the energies of the prominent (M{sub i}-S{sub j}) (S{sub j}=N{sub j}, O{sub j} and i =1-3, j =1-7) resonant Raman scattered (RRS) peaks at different incident photon energies have also been evaluated using the neutral-atommore » electron binding energies (E{sub sj}) based on the relaxed orbital relativistic Hartree-Fock-Slater model.« less

Influence of renormalization shielding on the electron-impact ionization process in dense partially ionized plasmas

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

Song, Mi-Young; Yoon, Jung-Sik; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr

2015-04-15

The renormalization shielding effects on the electron-impact ionization of hydrogen atom are investigated in dense partially ionized plasmas. The effective projectile-target interaction Hamiltonian and the semiclassical trajectory method are employed to obtain the transition amplitude as well as the ionization probability as functions of the impact parameter, the collision energy, and the renormalization parameter. It is found that the renormalization shielding effect suppresses the transition amplitude for the electron-impact ionization process in dense partially ionized plasmas. It is also found that the renormalization effect suppresses the differential ionization cross section in the peak impact parameter region. In addition, it ismore » found that the influence of renormalization shielding on the ionization cross section decreases with an increase of the relative collision energy. The variations of the renormalization shielding effects on the electron-impact ionization cross section are also discussed.« less

Thermal neutron radiative capture cross-section of 186W(n, γ)187W reaction

NASA Astrophysics Data System (ADS)

Tan, V. H.; Son, P. N.

2016-06-01

The thermal neutron radiative capture cross section for 186W(n, γ)187W reaction was measured by the activation method using the filtered neutron beam at the Dalat research reactor. An optimal composition of Si and Bi, in single crystal form, has been used as neutron filters to create the high-purity filtered neutron beam with Cadmium ratio of Rcd = 420 and peak energy En = 0.025 eV. The induced activities in the irradiated samples were measured by a high resolution HPGe digital gamma-ray spectrometer. The present result of cross section has been determined relatively to the reference value of the standard reaction 197Au(n, γ)198Au. The necessary correction factors for gamma-ray true coincidence summing, and thermal neutron self-shielding effects were taken into account in this experiment by Monte Carlo simulations.

Muscle anatomy and dynamic muscle function in osteogenesis imperfecta type I.

PubMed

Veilleux, Louis-Nicolas; Lemay, Martin; Pouliot-Laforte, Annie; Cheung, Moira S; Glorieux, Francis H; Rauch, Frank

2014-02-01

Results of previous studies suggested that children and adolescents with osteogenesis imperfecta (OI) type I have a muscle force deficit. However, muscle function has only been assessed by static isometric force tests and not in more natural conditions such as dynamic force and power tests. The purpose of this study was to assess lower extremity dynamic muscle function and muscle anatomy in OI type I. The study was performed in the outpatient department of a pediatric orthopedic hospital. A total of 54 individuals with OI type I (6-21 years; 20 male) and 54 age- and sex-matched controls took part in this study. Calf muscle cross-sectional area and density were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through 5 tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Compared with age- and sex-matched controls, patients with OI type I had smaller muscle size (P = .04) but normal muscle density (P = .21). They also had lower average peak force and lower specific force (peak force/muscle cross-sectional area; all P < .008). Average peak power was lower in patients with OI type I but not significantly so (all P > .054). Children and adolescents with OI type I have, on average, a significant force deficit in the lower limb as measured by dynamic force tests. Nonetheless, these data also show that OI type I is compatible with normal muscle performance in some individuals.

Determination of Fusion Barrier Distributions from Quasielastic Scattering Cross Sections towards Superheavy Nuclei Synthesis

NASA Astrophysics Data System (ADS)

Tanaka, Taiki; Narikiyo, Yoshihiro; Morita, Kosuke; Fujita, Kunihiro; Kaji, Daiya; Morimoto, Kouji; Yamaki, Sayaka; Wakabayashi, Yasuo; Tanaka, Kengo; Takeyama, Mirei; Yoneda, Akira; Haba, Hiromitsu; Komori, Yukiko; Yanou, Shinya; Jean-Paul Gall, Benoît; Asfari, Zouhair; Faure, Hugo; Hasebe, Hiroo; Huang, Minghui; Kanaya, Jumpei; Murakami, Masashi; Yoshida, Atsushi; Yamaguchi, Takayuki; Tokanai, Fuyuki; Yoshida, Tomomi; Yamamoto, Shoya; Yamano, Yuki; Watanabe, Kenyu; Ishizawa, Satoshi; Asai, Masato; Aono, Ryuji; Goto, Shin-ichi; Katori, Kenji; Hagino, Kouichi

2018-01-01

In order to study the nucleus-nucleus interactions for syntheses of superheavy nuclei, we measured excitation functions for the quasielastic scattering of 48Ca+208Pb, 50Ti+208Pb, and 48Ca+248Cm using the gas-filled-type recoil ion separator GARIS. The quasielastic scattering events were clearly separated from deep-inelastic events by using GARIS and its focal plan detectors, except for high-incident-energy points. The quasielastic barrier distributions were successfully extracted for these systems, and compared with coupled-channels calculations. The results of the calculations indicate that vibrational and rotational excitations of the colliding nuclei, as well as neutron transfers before contact, strongly affect the structure of the barrier distribution. For the reactions of 48Ca+208Pb and 50Ti+208Pb, a local maximum of the barrier distribution occurred at the same energy as the peak of the 2n evaporation cross section of the system. On the other hand, for the hot fusion reaction of 48Ca+248Cm, the 4n evaporation cross section of the system peaks at energies well above the maximum of the barrier distribution. This may be attributed to the deformation of the target nucleus. We argue that these findings can be utilized to locate the optimal energy for future searches for undiscovered superheavy nuclei.

Quantitative x-ray photoelectron spectroscopy: Quadrupole effects, shake-up, Shirley background, and relative sensitivity factors from a database of true x-ray photoelectron spectra

NASA Astrophysics Data System (ADS)

Seah, M. P.; Gilmore, I. S.

2006-05-01

An analysis is provided of the x-ray photoelectron spectroscopy (XPS) intensities measured in the National Physical Laboratory (NPL) XPS database for 46 solid elements. This present analysis does not change our previous conclusions concerning the excellent correlation between experimental intensities, following deconvolving the spectra with angle-averaged reflection electron energy loss data, and the theoretical intensities involving the dipole approximation using Scofield’s cross sections. Here, more recent calculations for cross sections by Trzhaskovskaya involving quadrupole terms are evaluated and it is shown that their cross sections diverge from the experimental database results by up to a factor of 5. The quadrupole angular terms lead to small corrections that are close to our measurement limit but do appear to be supported in the present analysis. Measurements of the extent of shake-up for the 46 elements broadly agree with the calculations of Yarzhemsky but not in detail. The predicted constancy in the shake-up contribution by Yarzhemsky implies that the use of the Shirley background will lead to a peak area that is a constant fraction of the true peak area including the shake-up intensities. However, the measured variability of the shake-up contribution makes the Shirley background invalid for quantification except for situations where the sensitivity factors are from reference samples similar to those being analyzed.

Calculation extinction cross sections and molar attenuation coefficient of small gold nanoparticles and experimental observation of their UV-vis spectral properties

NASA Astrophysics Data System (ADS)

Tang, Junqi; Gao, Kunpeng; Ou, Quanhong; Fu, Xuewen; Man, Shi-Qing; Guo, Jie; Liu, Yingkai

2018-02-01

Gold nanoparticles (AuNPs) have been researched extensively, such as applied in various biosensors, biomedical imaging and diagnosis, catalysis and physico-chemical analysis. These applications usually required to know the nanoparticle size or concentration. Researchers have been studying a simply and quick way to estimate the concentration or size of nanoparticles from their optical spectra and SPR feature for several years. The extinction cross-sections and the molar attenuation coefficient were one of the key parameters. In this study, we calculated the extinction cross-sections and molar attenuation coefficient (decadic molar extinction coefficient) of small gold nanoparticles by dipole approximation method and modified Beer-Lambert law. The theoretical result showed that the surface plasmon resonance peak of small gold nanoparticles was blueshift with an increase size. Moreover, small AuNPs (sub-10 nm) were prepared by using of dextran or trisodium citrate as reducing agent and capping agent. The experimental synthesized AuNPs was also shows a blueshift as increasing particle size in a certain range. And the concentration of AuNPs was calculated based on the obtained molar attenuation coefficient. For small nanoparticles, the size of nanoparticles and surface plasmon resonance property was not showed a positive correlation compared to larger nanoparticles. These results suggested that SPR peak depended not only on the nanoparticle size and shape but also on the nanoparticles environment.

The electronic and optical properties of quantum nano-structures

NASA Astrophysics Data System (ADS)

Ham, Heon

In semiconducting quantum nano-structures, the excitonic effects play an important role when we fabricate opto-electronic devices, such as lasers, diodes, detectors, etc. To gain a better understanding of the excitonic effects in quantum nano-structures, we investigated the exciton binding energy, oscillator strength, and linewidth in quantum nano-structures using both the infinite and finite well models. We investigated also the hydrogenic impurity binding energy and the photoionization cross section of the hydrogenic impurity in a spherical quantum dot. In our work, the variational approach is used in all calculations, because the Hamiltonian of the system is not separable, due to the different symmetries of the Coulomb and confining potentials. In the infinite well model of the semiconducting quantum nanostructures, the binding energy of the exciton increases with decreasing width of the potential barriers due to the increase in the effective strength of the Coulomb interaction between the electron and hole. In the finite well model, the exciton binding energy reaches a peak value, and the binding energy decreases with further decrease in the width of the potential barriers. The exciton linewidth in the infinite well model increases with decreasing wire radius, because the scattering rate of the exciton increases with decreasing wire radius. In the finite well model, the exciton linewidth in a cylindrical quantum wire reaches a peak value and the exciton linewidth decreases with further decrease in the wire radius, because the exciton is not well confined at very smaller wire radii. The binding energy of the hydrogenic impurity in a spherical quantum dot has also calculated using both the infinite and the finite well models. The binding energy of the hydrogenic impurity was calculated for on center and off center impurities in the spherical quantum dots. With decreasing radii of the dots, the binding energy of the hydrogenic impurity increases in the infinite well model. The binding energy of the hydrogenic impurity in the finite well model reaches a peak value and decreases with further decrease in the dot radii for both on center and off center impurities. We have calculated the photoionization cross section as a function of the radius and the frequency using both the infinite and finite well models. The photoionizaton cross section has a peak value at a frequency where the photon energy equals the difference between the final and initial state energies of the impurity. The behavior of the cross section with dot radius depends upon the location of the impurity and the polarization of the electromagnetic field.

Low energy electron spectroscopy of C60 in collisions with fast bare ions: Observation of GDPR peak and its angular distribution

NASA Astrophysics Data System (ADS)

Kelkar, A. H.; Misra, D.; Chatterjee, S.; Kasthurirangan, S.; Agnihotri, A.; Tribedi, L. C.

2009-11-01

We report the first direct measurement of GDPR peak in heavy ion (4 MeV/u F9+) induced secondary electron DDCS (double differential cross section) spectrum of C60 fullerene. A peak corresponding to GDPR is seen at all angles and the angular distribution, showing a dip at 90°, is in contrast with ion-atom collisions, indicating plasmon oscillations along beam direction. A comparison has also been done between C60 and other gaseous targets as well as with state-of-the art theoretical models, based on density functional methods.

A study on the measurement of radar cross section of flighting model based on the range-Doppler imaging

NASA Astrophysics Data System (ADS)

Hashimoto, Osamu; Mizokami, Osamu

The method for measuring radar cross section (RCS) based on Range-Doppler Imaging is discussed. In this method, the measured targets are rotated and the Doppler frequencies caused by each scattering element along the targets are analyzed by FFT. Using this method, each scattered power peak along the flying model is measured. It is found that each part of the RCS of a flying model can be measured and its RCS of a main wing (about 46 dB/sq cm) is greater than of its body (about 20-30 dB/sq cm).

The hydrogen anomaly problem in neutron Compton scattering

NASA Astrophysics Data System (ADS)

Karlsson, Erik B.

2018-03-01

Neutron Compton scattering (also called ‘deep inelastic scattering of neutrons’, DINS) is a method used to study momentum distributions of light atoms in solids and liquids. It has been employed extensively since the start-up of intense pulsed neutron sources about 25 years ago. The information lies primarily in the width and shape of the Compton profile and not in the absolute intensity of the Compton peaks. It was therefore not immediately recognized that the relative intensities of Compton peaks arising from scattering on different isotopes did not always agree with values expected from standard neutron cross-section tables. The discrepancies were particularly large for scattering on protons, a phenomenon that became known as ‘the hydrogen anomaly problem’. The present paper is a review of the discovery, experimental tests to prove or disprove the existence of the hydrogen anomaly and discussions concerning its origin. It covers a twenty-year-long history of experimentation, theoretical treatments and discussions. The problem is of fundamental interest, since it involves quantum phenomena on the subfemtosecond time scale, which are not visible in conventional thermal neutron scattering but are important in Compton scattering where neutrons have two orders of magnitude times higher energy. Different H-containing systems show different cross-section deficiencies and when the scattering processes are followed on the femtosecond time scale the cross-section losses disappear on different characteristic time scales for each H-environment. The last section of this review reproduces results from published papers based on quantum interference in scattering on identical particles (proton or deuteron pairs or clusters), which have given a quantitative theoretical explanation both regarding the H-cross-section reduction and its time dependence. Some new explanations are added and the concluding chapter summarizes the conditions for observing the specific quantum phenomena observed in neutron Compton scattering on protons and deuterons in condensed systems.

Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study

PubMed Central

Lynch, Heidi M.; Wharton, Christopher M.; Johnston, Carol S.

2016-01-01

In spite of well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance. In this cross-sectional study, we compared elite vegetarian and omnivore adult endurance athletes for maximal oxygen uptake (VO2 max) and strength. Twenty-seven vegetarian (VEG) and 43 omnivore (OMN) athletes were evaluated using VO2 max testing on the treadmill, and strength assessment using a dynamometer to determine peak torque for leg extensions. Dietary data were assessed using detailed seven-day food logs. Although total protein intake was lower among vegetarians in comparison to omnivores, protein intake as a function of body mass did not differ by group (1.2 ± 0.3 and 1.4 ± 0.5 g/kg body mass for VEG and OMN respectively, p = 0.220). VO2 max differed for females by diet group (53.0 ± 6.9 and 47.1 ± 8.6 mL/kg/min for VEG and OMN respectively, p < 0.05) but not for males (62.6 ± 15.4 and 55.7 ± 8.4 mL/kg/min respectively). Peak torque did not differ significantly between diet groups. Results from this study indicate that vegetarian endurance athletes’ cardiorespiratory fitness was greater than that for their omnivorous counterparts, but that peak torque did not differ between diet groups. These data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes. PMID:27854281

Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study.

PubMed

Lynch, Heidi M; Wharton, Christopher M; Johnston, Carol S

2016-11-15

In spite of well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance. In this cross-sectional study, we compared elite vegetarian and omnivore adult endurance athletes for maximal oxygen uptake (VO2 max) and strength. Twenty-seven vegetarian (VEG) and 43 omnivore (OMN) athletes were evaluated using VO2 max testing on the treadmill, and strength assessment using a dynamometer to determine peak torque for leg extensions. Dietary data were assessed using detailed seven-day food logs. Although total protein intake was lower among vegetarians in comparison to omnivores, protein intake as a function of body mass did not differ by group (1.2 ± 0.3 and 1.4 ± 0.5 g/kg body mass for VEG and OMN respectively, p = 0.220). VO2 max differed for females by diet group (53.0 ± 6.9 and 47.1 ± 8.6 mL/kg/min for VEG and OMN respectively, p < 0.05) but not for males (62.6 ± 15.4 and 55.7 ± 8.4 mL/kg/min respectively). Peak torque did not differ significantly between diet groups. Results from this study indicate that vegetarian endurance athletes' cardiorespiratory fitness was greater than that for their omnivorous counterparts, but that peak torque did not differ between diet groups. These data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.

Fully differential cross sections for the single ionization of helium by fast ions: Classical model calculations

NASA Astrophysics Data System (ADS)

Sarkadi, L.

2018-04-01

Fully differential cross sections (FDCSs) have been calculated for the single ionization of helium by 1- and 3-MeV proton and 100-MeV/u C6 + ion impact using the classical trajectory Monte Carlo (CTMC) method in the nonrelativistic, three-body approximation. The calculations were made employing a Wigner-type model in which the quantum-mechanical position distribution of the electron is approximated by a weighted integral of the microcanonical distribution over a range of the binding energy of the electron. In the scattering plane, the model satisfactorily reproduces the observed shape of the binary peak. In the region of the peak the calculated FDCSs agree well with the results of continuum-distorted-wave calculations for all the investigated collisions. For 1-MeV proton impact the experimentally observed shift of the binary peak with respect to the first Born approximation is compared with the shifts obtained by different higher-order quantum-mechanical theories and the present CTMC method. The best result was achieved by CTMC, but still a large part of the shift remained unexplained. Furthermore, it was found that the classical theory failed to reproduce the shape of the recoil peak observed in the experiments, it predicts a much narrower peak. This indicates that the formation of the recoil peak is dominated by quantum-mechanical effects. For 100-MeV/u C6 + ion impact the present CTMC calculations confirmed the existence of the "double-peak" structure of the angular distribution of the electron in the plane perpendicular to the momentum transfer, in accordance with the observation, the prediction of an incoherent semiclassical model, and previous CTMC results. This finding together with wave-packet calculations suggests that the "C6 + puzzle" may be solved by considering the loss of the projectile coherence. Experiments to be conducted using ion beams of anisotropic coherence are proposed for a more differential investigation of the ionization dynamics.

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

PubMed Central

Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan RT

2016-01-01

Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function. PMID:29805194

Description of chronostratigraphic units preserved as channel deposits and geomorphic processes following a basin-scale disturbance by a wildfire in Colorado

USGS Publications Warehouse

Moody, John A.; Martin, Deborah A.

2017-10-11

The consequence of a 1996 wildfire disturbance and a subsequent high-intensity summer convective rain storm (about 110 millimeters per hour) was the deposition of a sediment superslug in the Spring Creek basin (26.8 square kilometers) of the Front Range Mountains in Colorado. Spring Creek is a tributary to the South Platte River upstream from Strontia Springs Reservoir, which supplies domestic water for the cities of Denver and Aurora. Changes in a superslug were monitored over the course of 18 years (1996–2014) by repeat surveys at 18 channel cross sections spaced at nearly equal intervals along a 1,500-meter study reach and by a time series of photographs of each cross section. Surveys were not repeated at regular time intervals but after major changes caused by different geomorphic processes. The focus of this long-term study was to understand the evolution and internal alluvial architecture of chronostratigraphic units (defined as the volume of sediment deposited between two successive surveys), and the preservation or storage of these units in the superslug. The data are presented as a series of 18 narratives (one for each cross section) that summarize the changes, illustrate these changes with photographs, and provide a preservation plot showing the amount of each chronostratigraphic unit still remaining in June 2014.The most significant hydrologic change after the wildfire was an exponential decrease in peak discharge of flash floods caused by summer convective rain storms. In response to these hydrologic changes, all 18 locations went through an aggradation phase, an incision phase, and finally a stabilization phase. However, the architecture of the chronostratigraphic units differs from cross section to cross section, and units are characterized by either a laminar, fragmented, or hybrid alluvial architecture. In response to the decrease in peak-flood discharge and the increase in hillslope and riparian vegetation, Spring Creek abandoned many of the nearly horizontal erosional and depositional surfaces and left a landscape consisting of a series of cut-and-fill terraces as a legacy of this wildfire disturbance. 

Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at sqrt{s} = 7 TeV

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

Chatrchyan, Serguei; et al.,

2013-12-01

Measurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5(4.8) inverse femtobarns in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at sqrt{s} = 7 TeV. The measured inclusive cross section in the Z-peak region (60-120 GeV) is \\sigma(\\ell \\ell) = 986.4 +/- 0.6 (stat.) +/- 5.9 (exp. syst.) +/- 21.7 (th. syst.) +/- 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sectionsmore » $$d\\sigma/dm$$ for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d^2\\sigma/dm d |y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions.« less

Is localized infrared spectroscopy now possible in the electron microscope?

PubMed

Rez, Peter

2014-06-01

The recently developed in-column monochromators make it possible to record energy-c spectra with resolutions better than 30 meV from nanometer-sized regions. It should therefore in principle be possible to detect localized vibrational excitations. The scattering geometry in the electron microscope means that bond stretching in the specimen plane or longitudinal optic phonons dominate the scattering. Most promising for initial studies are vibrations with energies between 300 and 400 meV from hydrogen bonded to other atoms. Estimates of the scattering cross-sections on the basis of a simple model show that they are about the same as inner shell scattering cross-sections. Cross-sections also increase with charge transfer between the atoms, and theory incorporating realistic charge distributions shows that signal/noise is the only limitation to high-resolution imaging. Given the magnitude of the scattering cross-sections, minimizing the tail of the zero-loss peak is just as important as achieving a small-width at half-maximum. Improvements in both resolution and controlling the zero-loss tail will be necessary before it is practical to detect optic phonons in solids between 40 and 60 meV.

Level structure and production cross section of {sub {Xi}}{sup 12} Be studied with coupled-channels antisymmetrized molecular dynamics

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

Matsumiya, H.; Tsubakihara, K.; Kimura, M.

A theoretical framework of coupled-channels antisymmetrized molecular dynamics that describes the multistrangeness system with mixing between different baryon species is developed and applied to {sub {Lambda}}{sup 12}C and {sub {Xi}}{sup 12}Be. By introducing a minor modification to the YN G-matrix interaction derived from the Nijmegen model-D, the low-lying level structure and production cross section of {sub {Lambda}}{sup 12}C are reasonably described. It is found that the low-lying states of {sub {Xi}}{sup 12}Be are dominated by the {sup 11}B {circle_times} {Xi}{sup -} channel and their order strongly depends on {Xi}N effective interactions used in the calculation. The calculated peak position ofmore » the production cross section depends on the {Xi}N effective interaction and the magnitude of spin-flip and non-spin-flip cross sections of K{sup -}p{yields}K{sup +}{Xi}{sup -} elemental processes. We suggest that the {sup 12}C(K{sup -},K{sup +}){sub {Xi}}{sup 12}Be reaction possibly provides us information about the {Xi}N interaction.« less

Vertical drop test of a transport fuselage section located aft of the wing

NASA Technical Reports Server (NTRS)

Fasanella, E. L.; Alfaro-Bou, E.

1986-01-01

A 12-foot long Boeing 707 aft fuselage section with a tapering cross section was drop tested at the NASA Langley Research Center to measure structural, seat, and occupant response to vertical crash laods and to provide data for nonlinear finite element modeling. This was the final test in a series of three different transport fuselage sections tested under identical conditions. The test parameters at impact were: 20 ft/s velocity, and zero pitch, roll, and yaw. In addition, the test was an operational shock test of the data acquisition system used for the Controlled Impact Demonstration (CID) of a remotely piloted Boeing 720 that was crash tested at NASA Ames Dryden Flight Research Facility on December 1, 1984. Post-test measurements of the crush showed that the front of the section (with larger diameter) crushed vertically approximately 14 inches while the rear crushed 18 inches. Analysis of the data traces indicate the maximum peak normal (vertical) accelerations at the bottom of the frames were approximately 109 G at body station 1040 and 64 G at body station 1120. The peak floor acceleration varied from 14 G near the wall to 25 G near the center where high frequency oscillations of the floor were evident. The peak anthropomorphic dummy pelvis normal (vertical) acceleration was 19 G's.

The e{sup +}e{sup -}{yields}J/{psi}DD-bar, J/{psi}DD-bar* reactions with dynamically generated resonances

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

Gamermann, D.; Oset, E.

2008-08-31

In two recent reactions by Belle producing DD-bar and DD-bar* meson pairs, peaks above threshold have been measured in the differential cross sections, possibly indicating new resonances in these channels. We want to study such reactions from the point of view that the D meson pairs are produced from already known or predicted resonances below threshold. Our study shows that the peak in the DD-bar* production is not likely to be caused by the X(3872) resonance, but the peak seen in DD-bar invariant mass can be well described if the DD-bar pair comes from the already predicted scalar X(3700) resonance.

Quadriceps Function and Knee Joint Ultrasonography after ACL Reconstruction.

PubMed

Pamukoff, Derek N; Montgomery, Melissa M; Moffit, Tyler J; Vakula, Michael N

2018-02-01

Individuals with anterior cruciate ligament reconstruction (ACLR) are at greater risk for knee osteoarthritis, partially because of chronic quadriceps dysfunction. Articular cartilage is commonly assessed using magnetic resonance imaging and radiography, but these methods are expensive and lack portability. Ultrasound imaging may provide a cost-effective and portable alternative for imaging the femoral cartilage. The purpose of this study was to compare ultrasonography of the femoral cartilage between the injured and uninjured limbs of individuals with unilateral ACLR, and to examine the association between quadriceps function and ultrasonographic measures of femoral cartilage. Bilateral femoral cartilage thickness and quadriceps function were assessed in 44 individuals with unilateral ACLR. Quadriceps function was assessed using peak isometric strength, and early (RTD100) and late (RTD200) rate of torque development. Cartilage thickness at the medial femoral condyle (P < 0.001) and femoral cartilage cross-sectional area (P = 0.007) were smaller in the injured compared with the uninjured limb. After accounting for time since ACLR, quadriceps peak isometric strength was associated with cartilage thickness at the medial femoral condyle (r = 0.35, P = 0.02) and femoral cartilage cross-sectional area (r = 0.28, P = 0.04). RTD100 and RTD200 were not associated with femoral cartilage thickness or cross-sectional area. Individuals with ACLR have thinner cartilage in their injured limb compared with uninjured limb, and cartilage thickness is associated with quadriceps function. These results indicate that ultrasonography may be useful for monitoring cartilage health and osteoarthritis progression after ACLR.

Calculation extinction cross sections and molar attenuation coefficient of small gold nanoparticles and experimental observation of their UV-vis spectral properties.

PubMed

Tang, Junqi; Gao, Kunpeng; Ou, Quanhong; Fu, Xuewen; Man, Shi-Qing; Guo, Jie; Liu, Yingkai

2018-02-15

Gold nanoparticles (AuNPs) have been researched extensively, such as applied in various biosensors, biomedical imaging and diagnosis, catalysis and physico-chemical analysis. These applications usually required to know the nanoparticle size or concentration. Researchers have been studying a simply and quick way to estimate the concentration or size of nanoparticles from their optical spectra and SPR feature for several years. The extinction cross-sections and the molar attenuation coefficient were one of the key parameters. In this study, we calculated the extinction cross-sections and molar attenuation coefficient (decadic molar extinction coefficient) of small gold nanoparticles by dipole approximation method and modified Beer-Lambert law. The theoretical result showed that the surface plasmon resonance peak of small gold nanoparticles was blueshift with an increase size. Moreover, small AuNPs (sub-10nm) were prepared by using of dextran or trisodium citrate as reducing agent and capping agent. The experimental synthesized AuNPs was also shows a blueshift as increasing particle size in a certain range. And the concentration of AuNPs was calculated based on the obtained molar attenuation coefficient. For small nanoparticles, the size of nanoparticles and surface plasmon resonance property was not showed a positive correlation compared to larger nanoparticles. These results suggested that SPR peak depended not only on the nanoparticle size and shape but also on the nanoparticles environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Propensity for distinguishing two free electrons with equal energies in electron-impact ionization of helium

NASA Astrophysics Data System (ADS)

Ren, Xueguang; Senftleben, Arne; Pflüger, Thomas; Bartschat, Klaus; Zatsarinny, Oleg; Berakdar, Jamal; Colgan, James; Pindzola, Michael S.; Bray, Igor; Fursa, Dmitry V.; Dorn, Alexander

2015-11-01

We report a combined experimental and theoretical study on the electron-impact ionization of helium at E0=70.6 eV and equal energy sharing of the two outgoing electrons (E1=E2=23 eV ), where a double-peak or dip structure in the binary region of the triple differential cross section is observed. The experimental cross sections are compared with results from convergent close-coupling (CCC), B -spline R-matrix-with-pseudostates (BSR), and time-dependent close-coupling (TDCC) calculations, as well as predictions from the dynamic screening three-Coulomb (DS3C) theory. Excellent agreement is obtained between experiment and the nonperturbative CCC, BSR, and TDCC theories, and good agreement is also found for the DS3C model. The data are further analyzed regarding contributions in particular coupling schemes for the spins of either the two outgoing electrons or one of the outgoing electrons and the 1 s electron remaining in the residual ion. While both coupling schemes can be used to explain the observed double-peak structure in the cross section, the second one allows for the isolation of the exchange contribution between the incident projectile and the target. For different observation angles of the two outgoing electrons, we interpret the results as a propensity for distinguishing these two electrons—one being more likely the incident projectile and the other one being more likely ejected from the target.

Neutron production cross sections for (d,n) reactions at 55 MeV

NASA Astrophysics Data System (ADS)

Wakasa, T.; Goto, S.; Matsuno, M.; Mitsumoto, S.; Okada, T.; Oshiro, H.; Sakaguchi, S.

2017-08-01

The cross sections for (d,n) reactions on {}^natC-{}^{197}Au have been measured at a bombarding energy of 55 MeV and a laboratory scattering angle of θ_lab = 9.5°. The angular distributions for the {}^natC(d,n) reaction have also been obtained at θ_lab = 0°-40°. The neutron energy spectra are dominated by deuteron breakup contributions and their peak positions can be reasonably reproduced by considering the Coulomb force effects. The data are compared with the TENDL-2015 nuclear data and Particle and Heavy Ion Transport code System (PHITS) calculations. Both calculations fail to reproduce the measured energy spectra and angular distributions.

Electron impact excitation of argon in the extreme vacuum ultraviolet

NASA Technical Reports Server (NTRS)

Mentall, J. E.; Morgan, H. D.

1976-01-01

Polarization-free excitation cross sections in the extreme vacuum ultraviolet have been measured for electron impact on Ar. Observed spectral features were those lines of Ar I and Ar II which lie between 700 and 1100 A. Excitation functions were measured for the Ar I resonance line at 1048 A and the Ar II resonance line at 920 A. Peak cross sections for these two lines were found to be (39.4 plus or minus 7.9) x 10 to the -18th and (6.9 plus or minus 1.4) x 10 to the -18th, respectively. At low energies, excitation of the Ar II resonance line is dominated by an electron exchange transition.

Measurements of exclusive photoproduction processes at large values of t and u from 4 to 7.5 GeV

USGS Publications Warehouse

Anderson, R.L.; Gustavson, D.B.; Ritson, D.M.; Weitsch, G.A.; Halpern, H.J.; Prepost, R.; Tompkins, Donald H.; Wiser, D.E.

1976-01-01

Exclusive photoproduction cross sections have been measured for the processes p+n, p0p, p-++, p0p, pK+, and pK+0 at large t and u values at several energies for each process between 4 and 7.5 GeV. These measurements taken together with past data taken at small values of t and u provide complete angular distributions. The data show the usual small t and u peaks and a central region in which the cross section decreases approximately as s-7. The results are discussed within the context of parton or constituent models. ?? 1976 The American Physical Society.

Dissociative attachment of electrons to N2O

NASA Technical Reports Server (NTRS)

Krishnakumar, E.; Srivastava, S. K.

1990-01-01

Cross sections for the production of O(-) from N2O by the process of dissociative electron attachment have been measured for electron-impact energies ranging from 0 to 50 eV. Three new O(-) peaks are observed. The present data above 5-eV electron-impact energy differ considerably from the previous measurements.

Pressurized Wideband Absorbance Findings in Healthy Neonates: A Preliminary Study

ERIC Educational Resources Information Center

Wali, Hamzah A.; Mazlan, Rafidah; Kei, Joseph

2017-01-01

Purpose: The present study aimed to establish normative data for wideband absorbance (WBA) measured at tympanometric peak pressure (TPP) and 0 daPa and to assess the test-retest reliability of both measurements in healthy neonates. Method: Participants of this cross-sectional study included 99 full-term neonates (165 ears) with mean chronological…

Properties of micro-arc oxidation coatings on aluminum alloy at different negative peak current densities

NASA Astrophysics Data System (ADS)

Gu, Xin; Jiang, Bailing; Li, Hongtao; Liu, Cancan; Shao, Lianlian

2018-05-01

Micro-arc oxidation coatings were fabricated on 6061 aluminum alloy using whereby bipolar pulse mode in the case of different negative peak current densities. The phase composition, microstructures and wear properties were studied using x-ray diffraction, scanning electron microscopy and ball-on-disk wear tester, respectively. As results indicate, by virtue of negative peak current density, the oxygen can be expelled by produced hydrogen on anode in the case of negative pulse width and via the opened discharge channel. The results of x-ray diffraction, surface and cross-sectional morphology indicated that the coating was structured compactly taking on less small-diameter micro-pores and defects with negative peak current density of 75 A dm‑2. Additionally, as the results of wear tracks and weight loss bespeak, by virtue of appropriate negative peak current density, coatings resisted the abrasive wear and showed excellent wear resistance.

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

Ren, X.; Senftleben, A.; Pflueger, T.

Absolutely normalized (e,2e) measurements for H{sub 2} and He covering the full solid angle of one ejected electron are presented for 16 eV sum energy of both final state continuum electrons. For both targets rich cross-section structures in addition to the binary and recoil lobes are identified and studied as a function of the fixed electron's emission angle and the energy sharing among both electrons. For H{sub 2} their behavior is consistent with multiple scattering of the projectile as discussed before [Al-Hagan et al., Nature Phys. 5, 59 (2009)]. For He the binary and recoil lobes are significantly larger thanmore » for H{sub 2} and partly cover the multiple scattering structures. To highlight these patterns we propose a alternative representation of the triply differential cross section. Nonperturbative calculations are in good agreement with the He results and show discrepancies for H{sub 2} in the recoil peak region. For H{sub 2} a perturbative approach reasonably reproduces the cross-section shape but deviates in absolute magnitude.« less

X-ray and gamma-ray line production by nonthermal ions

NASA Technical Reports Server (NTRS)

Bussard, R. W.; Omidvar, K.; Ramaty, R.

1977-01-01

X-ray production was calculated at approximately 6.8 keV by the 2p to 1s transition in fast hydrogen- and helium-like iron ions, following both electron capture to excited levels and collisional excitation. A refinement of the OBK approximation was used to obtain an improved charge exchange cross section. This, and the corresponding ionization cross section were used to determine equilibrium charge fractions for iron ions as functions of their energy. The effective X-ray line production cross section was found to be sharply peaked in energy at about 8 to 12 MeV/amu. Because fast ions of similar energies can also excite nuclear levels, the ratio of selected strong gamma ray line emissivities to the X-ray line emissivity was also calculated. Limits set by this method on the intensity of gamma ray line emission from the galactic center and the radio galaxy Centaurus A are generally lower than those reported in the literature.

Radiation and chemistry in the stratosphere - Sensitivity to O2 absorption cross sections in the Herzberg continuum

NASA Technical Reports Server (NTRS)

Froidevaux, L.; Yung, Y. L.

1982-01-01

It is suggested that the discrepancies between observed and modeled vertical profiles of such halocarbons as CFCl3, as well as the problem of simultaneously fitting N2O, CH4, CF2Cl2 and CFCl3 profiles with a single eddy diffusion model, are due to an overestimation of the molecular oxygen absorption cross sections in the 200-220 nm spectral region. The replacement of current O2 cross sections in this range with values that are in better agreement with results for the compounds cited leads to N2O, CF2Cl2 and CFCl3 concentration reductions of factors 0.70, 0.62 and 0.19, respectively. Profiles of CH4, H2 and CO remain unchanged, and the predicted concentration of HNO3 above 30 km is reduced by about 50% for yet another improved fit with observations. It is noted that the correction proposed produces a 30% ozone increase near the 20-25 km peak.

Projectile-charge dependence of the differential cross section for the ionization of argon atoms at 1 keV

NASA Astrophysics Data System (ADS)

Purohit, G.; Kato, D.

2017-10-01

The single ionization triple differential cross sections (TDCS) of the Ar (3 p ) atoms are reported for the positron and electron impact at 1 keV. The calculated cross sections have been obtained using distorted wave Born approximation (DWBA) approach for the average ejected electron energies 13 and 26 eV at different momentum transfer conditions. The present attempt is helpful to probe the information on the TDCS trends for the particle-matter and antiparticle-matter interactions and to analyze the recent measurements [Phy. Rev. A 95, 062703 (2017), 10.1103/PhysRevA.95.062703]. The binary electron emission is enhanced while the recoil emission is decreased for the positron impact relative to the electron impact in the DWBA calculation results. Systematic shift of peaks, shifting away from the momentum transfer direction for positron impact and shifting towards each other for electron impact, is observed with increasing momentum transfer.

Total and differential cross sections of η-production in proton-deuteron fusion for excess energies between Qη = 13 MeV and Qη = 81 MeV

NASA Astrophysics Data System (ADS)

Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Czerwiński, E.; Demmich, K.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Heijkenskjöld, L.; Hejny, V.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khatri, G.; Khoukaz, A.; Khreptak, A.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Parol, W.; Perez del Rio, E.; Piskunov, N. M.; Prasuhn, D.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Rundel, O.; Sawant, S.; Schadmand, S.; Schätti-Ozerianska, I.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Sitterberg, K.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Trzciński, A.; Wolke, M.; Wrońska, A.; Wüstner, P.; Yamamoto, A.; Zabierowski, J.; Zieliński, M. J.; Złomańczuk, J.; Żuprański, P.; Żurek, M.; Wilkin, C.; WASA-at-COSY Collaboration

2018-07-01

New data on both total and differential cross sections of the production of η mesons in proton-deuteron fusion to 3He η in the excess energy region 13.6MeV ≤Qη ≤ 80.9MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Jülich, using a proton beam at 15 different beam momenta between pp = 1.60GeV / c and pp = 1.74GeV / c. While significant structure of the total cross section is observed in the energy region 20MeV ≲Qη ≲ 60MeV, a previously reported sharp variation around Qη ≈ 50MeV cannot be confirmed. Angular distributions show the typical forward-peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval.

Line Profile of H Lyman (alpha) from Dissociative Excitation of H2 with Application to Jupiter

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Kasnik, Isik; Ahmed, Syed M.; Clarke, John T.

1995-01-01

Observations of the H Lyman(alpha) (Ly-alpha) emission from Jupiter have shown pronounced emissions, exceeding solar fluorescence, in the polar aurora and equatorial "bulge" regions. The H Ly-alpha line profiles from these regions are broader than expected, indicating high-energy processes producing fast atoms as determined from the observed Doppler broadening. Toward understanding that process a high-resolution ultraviolet (UV) spectrometer was employed for the first measurement of the H Ly-alpha emission Doppler profile from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak of 40 +/- 4 mA full width at half maximum and a broad pedestal base about 240 mA wide. Two distinct dissociation mechanisms account for this Doppler structure. Slow H(2p) atoms characterized by a distribution function with peak energy near 80 meV produce the peak profile, which is nearly independent of the electron impact energy. Slow H(2p) atoms arise from direct dissociation and predissociation of singly excited states which have a dissociation limit of 14.68 eV. The wings of H Ly-alpha arise from dissociative excitation of a series of doubly excited states which cross the Franck-Condon region between 23 and 40 eV. The profile of the wings is dependent on the electron impact energy, and the distribution function of fast H(2p) atoms is therefore dependent on the electron impact energy. The fast atom kinetic energy distribution at 100 eV electron impact energy spans the energy range from 1 to 10 eV with a peak near 4 eV. For impact energies above 23 eV the fast atoms contribute to a slightly asymmetric structure of the line profile. The absolute cross sections of the H Ly-alpha line peak and wings were measured over the range from 0 to 200 eV. Analytic model coefficients are given for the measured cross sections which can be applied to planetary atmosphere auroral and dayglow calculations. The dissociative excitation process, while one contributing process, appears insufficient by itself to explain the line broadening observed at Jupiter.

Structure and chemical composition of the dentin-enamel junction analyzed by Confocal Raman Microscopy

NASA Astrophysics Data System (ADS)

Desoutter, A.; Salehi, H.; Slimani, A.; Marquet, P.; Jacquot, B.; Tassery, H.; Cuisinier, F. J. G.

2014-02-01

The structure and chemical composition of the human dentin-enamel junction (DEJ) was studied using confocal Raman microscopy - a chemical imaging technique. Slices of non-fixed, sound teeth were prepared with an Isomet diamond saw and scanned with Witec Alpha300R system. The combination of different characteristics peaks of phosphate, carbonate and organic matrix (respectively 960, 1072 and 1545 cm-1), generates images representing the chemical composition of the DEJ area. Images are also calculated using peak ratios enabling precise determination of the chemical composition across the DEJ. Then, with two characterized peaks, different pictures are calculated to show the ratio of two components. The images of the spatial distribution of mineral phosphate (960cm-1) to organic matrix (1545 cm-1) ratios, mineral carbonates (1072cm-1) to mineral phosphate ratios; and mineral carbonates to organic matrix ratios were reconstructed. Cross sectional and calculated graphic profile show the variations of the different chemical component ratios through the enamel and the dentin. Phosphate to organic ratio shows an accumulation of organic material under the enamel surface. The cross sectional profile of these pictures shows a high phosphate content compared to enamel in the vicinity of the DEJ. The Confocal Raman imaging technique can be used to further provide full chemical imaging of tooth, particularly of the whole DEJ and to study enamel and dentin decay.

Line Profile of H Lyman-Beta Emission from Dissociative Excitation of H2

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Ahmed, Syed M.; Liu, Xian-Ming

1996-01-01

A high-resolution ultraviolet spectrometer was employed for a measurement of the H Lyman-Beta(H L(sub Beta)) emission Doppler line profile at 1025.7 A from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak, less than 30 mA full width at half maximum (FWHM), and a broad pedestal base about 260 mA FWHM. Analysis of the red wing of the line profile is complicated by a group of Wemer and Lyman rotational lines 160-220 mA from the line center. Analysis of the blue wing of the line profile gives the kinetic-energy distribution. There are two main kinetic-energy components to the H(3p) distribution: (1) a slow distribution with a peak value near 0 eV from singly excited states, and (2) a fast distribution with a peak contribution near 7 eV from doubly excited states. Using two different techniques, the absolute cross section of H L(sub Beta)p is found to be 3.2+/-.8 x 10(exp -19)sq cm at 100-eV electron impact energy. The experimental cross-section and line-profile results can be compared to previous studies of H(alpha) (6563.7 A) for principal quantum number n=3 and L(sub alpha)(1215.7 A) for n=2.

Characterization of fast photoelectron packets in weak and strong laser fields in ultrafast electron microscopy.

PubMed

Plemmons, Dayne A; Tae Park, Sang; Zewail, Ahmed H; Flannigan, David J

2014-11-01

The development of ultrafast electron microscopy (UEM) and variants thereof (e.g., photon-induced near-field electron microscopy, PINEM) has made it possible to image atomic-scale dynamics on the femtosecond timescale. Accessing the femtosecond regime with UEM currently relies on the generation of photoelectrons with an ultrafast laser pulse and operation in a stroboscopic pump-probe fashion. With this approach, temporal resolution is limited mainly by the durations of the pump laser pulse and probe electron packet. The ability to accurately determine the duration of the electron packets, and thus the instrument response function, is critically important for interpretation of dynamics occurring near the temporal resolution limit, in addition to quantifying the effects of the imaging mode. Here, we describe a technique for in situ characterization of ultrashort electron packets that makes use of coupling with photons in the evanescent near-field of the specimen. We show that within the weakly-interacting (i.e., low laser fluence) regime, the zero-loss peak temporal cross-section is precisely the convolution of electron packet and photon pulse profiles. Beyond this regime, we outline the effects of non-linear processes and show that temporal cross-sections of high-order peaks explicitly reveal the electron packet profile, while use of the zero-loss peak becomes increasingly unreliable. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of the routing procedure to study dye and gas transport in the West Fork Trinity River, Texas

USGS Publications Warehouse

Jobson, Harvey E.; Rathbun, R.E.

1984-01-01

Rhodamine-WT dye, ethylene, and propane were injected at three sites along a 21.6-kilometer reach of the West Fork Trinity River below Fort Worth, Texas. Complete dye concentration versus time curves and peak gas concentrations were measured at three cross sections below each injection. The peak dye concentrations were located and samples were collected at about three-hour intervals for as many as six additional cross sections. These data were analyzed to determine the longitudinal dispersion coefficients as well as the gas desorption coefficients using both standard techniques and a numerical routing procedure. The routing procedure, using a Lagrangian transport model to minimize numerical dispersion, provided better estimates of the dispersion coefficient than did the method of moments. At a steady flow of about 0.76 m2/s, the dispersion coefficient varied from about 0.7 m2/s in a reach contained within a single deep pool to about 2.0 m2/s in a reach containing riffles and small pools. The bulk desorption coefficients computed using the routing procedure and the standard peak method were essentially the same. The liquid film coefficient could also be obtained using the routing procedure. Both the bulk desorption coefficient and the liquid film coefficient were much smaller in the pooled reach than in the reaches containing riffles.

Analysis of Femoral Components of Cemented Total Hip Arthroplasty

NASA Astrophysics Data System (ADS)

Singh, Shantanu; Harsha, A. P.

2016-10-01

There have been continuous on-going revisions in design of prosthesis in Total Hip Arthroplasty (THA) to improve the endurance of hip replacement. In the present work, Finite Element Analysis was performed on cemented THA with CoCrMo trapezoidal, CoCrMo circular, Ti6Al4V trapezoidal and Ti6Al4V circular stem. It was observed that cross section and material of femoral stem proved to be critical parameters for stress distribution in femoral components, distribution of interfacial stress and micro movements. In the first part of analysis, designs were investigated for micro movements and stress developed, for different stem materials. Later part of the analysis focused on investigations with respect to different stem cross sections. Femoral stem made of Titanium alloy (Ti6Al4V) resulted in larger debonding of stem at cement-stem interface and increased stress within the cement mantle in contrast to chromium alloy (CoCrMo) stem. Thus, CoCrMo proved to be a better choice for cemented THA. Comparison between CoCrMo femoral stem of trapezium and circular cross section showed that trapezoidal stem experiences lesser sliding and debonding at interfaces than circular cross section stem. Also, trapezium cross section generated lower peak stress in femoral stem and cortical femur. In present study, femur head with diameter of 36 mm was considered for the analysis in order to avoid dislocation of the stem. Also, metallic femur head was coupled with cross linked polyethylene liner as it experiences negligible wear compared to conventional polyethylene liner and unlike metallic liner it is non carcinogenic.

Proposal for chiral-boson search at LHC via their unique new signature

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

Chizhov, M. V.; Bednyakov, V. A.; Budagov, J. A.

The resonance production of new chiral spin-1 bosons and their detection through the Drell-Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross sections of the chiral-boson production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit-Wigner resonance peak in the invariant-dilepton-mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse-momentum distribution. Second, the lepton angular distribution in the Collins-Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar 'swallowtail'more » shape.« less

Measurement of the e+e-→π+π-J/ψ Cross Section Via Initial-State Radiation at Belle

NASA Astrophysics Data System (ADS)

Yuan, C. Z.; Shen, C. P.; Wang, P.; McOnie, S.; Adachi, I.; Aihara, H.; Aulchenko, V.; Aushev, T.; Bahinipati, S.; Balagura, V.; Barberio, E.; Bedny, I.; Bitenc, U.; Bondar, A.; Bozek, A.; Bračko, M.; Brodzicka, J.; Browder, T. E.; Chang, M.-C.; Chang, P.; Chen, A.; Chen, K.-F.; Chen, W. T.; Cheon, B. G.; Chistov, R.; Cho, I.-S.; Choi, Y.; Dalseno, J.; Danilov, M.; Dash, M.; Eidelman, S.; Fratina, S.; Gabyshev, N.; Golob, B.; Ha, H.; Haba, J.; Hayasaka, K.; Hayashii, H.; Hazumi, M.; Heffernan, D.; Hokuue, T.; Hoshi, Y.; Hou, W.-S.; Hsiung, Y. B.; Hyun, H. J.; Iijima, T.; Ikado, K.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Kah, D. H.; Kaji, H.; Kang, J. H.; Katayama, N.; Kawai, H.; Kawasaki, T.; Kichimi, H.; Kim, Y. J.; Kinoshita, K.; Korpar, S.; Križan, P.; Krokovny, P.; Kumar, R.; Kuo, C. C.; Kuzmin, A.; Kwon, Y.-J.; Lee, S. E.; Lesiak, T.; Lin, S.-W.; Liu, Y.; Liventsev, D.; Mandl, F.; Marlow, D.; Matyja, A.; Medvedeva, T.; Mitaroff, W.; Miyabayashi, K.; Miyake, H.; Miyata, H.; Miyazaki, Y.; Mizuk, R.; Mori, T.; Nagasaka, Y.; Nakao, M.; Natkaniec, Z.; Nishida, S.; Nitoh, O.; Ogawa, S.; Ohshima, T.; Okuno, S.; Olsen, S. L.; Ozaki, H.; Pakhlov, P.; Pakhlova, G.; Palka, H.; Park, H.; Park, K. S.; Peak, L. S.; Piilonen, L. E.; Sakai, Y.; Schneider, O.; Schümann, J.; Seidl, R.; Senyo, K.; Sevior, M. E.; Shapkin, M.; Shibuya, H.; Shiu, J.-G.; Shwartz, B.; Singh, J. B.; Sokolov, A.; Somov, A.; Starič, M.; Sumiyoshi, T.; Takasaki, F.; Tanaka, M.; Taylor, G. N.; Teramoto, Y.; Tikhomirov, I.; Uehara, S.; Unno, Y.; Uno, S.; Usov, Y.; Varner, G.; Varvell, K. E.; Vervink, K.; Villa, S.; Vinokurova, A.; Wang, C. C.; Wang, C. H.; Wang, X. L.; Watanabe, Y.; Won, E.; Yabsley, B. D.; Yamaguchi, A.; Yamashita, Y.; Zhang, C. C.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

2007-11-01

The cross section for e+e-→π+π-J/ψ between 3.8 and 5.5GeV/c2 is measured using a 548fb-1 data sample collected on or near the Υ(4S) resonance with the Belle detector at KEKB. A peak near 4.25GeV/c2, corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05GeV/c2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.

Elastic break-up of 156 MeV 6Li projectiles with large asymptotic relative momenta of the fragments: . Experimental observations and the diffractive disintegration approach

NASA Astrophysics Data System (ADS)

Heide, N.; Rebel, H.; Corcalciuc, V.; Gils, H. J.; Jelitto, H.; Kiener, J.; Wentz, J.; Zagromski, S.; Srivastava, D. K.

1989-11-01

The triple-differential cross sections for elastic break-up of 156 MeV 6Li projectiles by the reactions 208Pb( 6Li, αd) 208Pb g.s. and 12C( 6Li, αd) 12C g.s. have been measured with large asymptotic relative momenta of the outgoing fragments. The data exhibit rather unfamiliar shapes of the energy spectra, often replacing the usual bell-shape distributions by double-peaked structures and varying rapidly with the relative emission angles. The origin of these features has been explored and the cross sections have been analysed on the basis of a diffractive disintegration approach.

Compact diode laser source for multiphoton biological imaging

PubMed Central

Niederriter, Robert D.; Ozbay, Baris N.; Futia, Gregory L.; Gibson, Emily A.; Gopinath, Juliet T.

2016-01-01

We demonstrate a compact, pulsed diode laser source suitable for multiphoton microscopy of biological samples. The center wavelength is 976 nm, near the peak of the two-photon cross section of common fluorescent markers such as genetically encoded green and yellow fluorescent proteins. The laser repetition rate is electrically tunable between 66.67 kHz and 10 MHz, with 2.3 ps pulse duration and peak powers >1 kW. The laser components are fiber-coupled and scalable to a compact package. We demonstrate >600 μm depth penetration in brain tissue, limited by laser power. PMID:28101420

Flood boundaries and water-surface profile for the computed 100-year flood, Swift Creek at Afton, Wyoming, 1986

USGS Publications Warehouse

Rankl, James G.; Wallace, Joe C.

1989-01-01

Flood flows on Swift Creek near Afton, Wyoming, were analyzed. Peak discharge with an average recurrence interval of 100 years was computed and used to determine the flood boundaries and water surface profile in the study reach. The study was done in cooperation with Lincoln County and the Town of Afton to determine the extent of flooding in the Town of Afton from a 100-year flood on Swift Creek. The reach of Swift Creek considered in the analysis extends upstream from the culvert at Allred County Road No. 12-135 to the US Geological Survey streamflow-gaging station located in the Bridger National Forest , a distance of 3.2 miles. Boundaries of the 100-year flood are delineated on a map using the computed elevation of the flood at each cross section, survey data, and a 1983 aerial photograph. The computed water surface elevation for the 100-year flood was plotted at each cross section, then the lateral extent of the flood was transferred to the flood map. Boundaries between cross sections were sketched using information taken from the aerial photograph. Areas that are inundated, but not part of the active flow, are designated on the cross sections. (Lantz-PTT)

Photoabsorption cross-section measurements of 32S, 33S, 34S, and 36S sulfur dioxide from 190 to 220 nm

NASA Astrophysics Data System (ADS)

Endo, Yoshiaki; Danielache, Sebastian O.; Ueno, Yuichiro; Hattori, Shohei; Johnson, Matthew S.; Yoshida, Naohiro; Kjaergaard, Henrik G.

2015-03-01

The ultraviolet absorption cross sections of the SO2 isotopologues are essential to understanding the photochemical fractionation of sulfur isotopes in planetary atmospheres. We present measurements of the absorption cross sections of 32SO2, 33SO2, 34SO2, and 36SO2, recorded from 190 to 220 nm at room temperature with a resolution of 0.1 nm (~25 cm-1) made using a dual-beam photospectrometer. The measured absorption cross sections show an apparent pressure dependence and a newly developed analytical model shows that this is caused by underresolved fine structure. The model made possible the calculation of absorption cross sections at the zero-pressure limit that can be used to calculate photolysis rates for atmospheric scenarios. The 32SO2, 33SO2, and 34SO2 cross sections improve upon previously published spectra including fine structure and peak widths. This is the first report of absolute absorption cross sections of the 36SO2 isotopologue for the C1B2-X1A2 band where the amplitude of the vibrational structure is smaller than the other isotopologues throughout the spectrum. Based on the new results, solar UV photodissociation of SO2 produces 34ɛ, 33Ε, and 36Ε isotopic fractionations of +4.6 ± 11.6‰, +8.8 ± 9.0‰, and -8.8 ± 19.6‰, respectively. From these spectra isotopic effects during photolysis in the Archean atmosphere can be calculated and compared to the Archean sedimentary record. Our results suggest that broadband solar UV photolysis is capable of producing the mass-independent fractionation observed in the Archean sedimentary record without involving shielding by specific gaseous compounds in the atmosphere including SO2 itself. The estimated magnitude of 33Ε, for example, is close to the maximum Δ33S observed in the geological record.

Measurements of Rayleigh, Compton and resonant Raman scattering cross-sections for 59.536 keV γ-rays

NASA Astrophysics Data System (ADS)

Singh, Prem; Mehta, D.; Singh, N.; Puri, S.; Shahi, J. S.

2004-09-01

The K-L and K-M resonant Raman scattering (RRS) cross-sections have been measured for the first time at the 59.536 keV photon energy in the 70Yb ( BK=61.332 keV), 71Lu ( BK=63.316 keV) and 72Hf ( BK=65.345 keV) elements; BK being the K-shell binding energy. The K-L and K-M RRS measurements have been performed at the 59° and 133° angles, respectively, to avoid interference of the Compton-scatter peak. The Rayleigh and Compton scattering cross-sections for the 59.536 keV γ-rays have also been measured at both the angles in the atomic region 1⩽ Z⩽92. Measurements were performed using the reflection-mode geometrical arrangements involving the 241Am radioisotope as photon source and planar Si(Li) and HPGe detectors. Ratios of the K-M and K-L RRS cross-sections in Yb, Lu and Hf are in general lower than that of the fluorescent Kβ 1,3,5 (K-M) and Kα (K-L) X-ray transition probabilities. Theoretical Rayleigh scattering cross-sections based on the modified form-factors (MFs) corrected for the anomalous scattering factors (ASFs) and the S-matrix calculations are on an average ˜15% and ˜6% higher, respectively, at the 133° angle and exhibit good agreement with the measured data at the 59° angle. Larger deviations ˜30% and ˜20%, respectively, are observed at the 133° angle for the 64Gd, 66Dy, 67Ho and 70Yb elements having the K-shell binding energy in vicinity of the incident photon energy. The measured Compton scattering cross-sections are in general agreement with those calculated using the Klein-Nishina cross-sections and the incoherent scattering function.

The role of postural control in the association between aerobic capacity and walking capacity in chronic stroke: a cross-sectional analysis.

PubMed

Outermans, Jacqueline C; van de Port, Ingrid; Kwakkel, Gert; Visser-Meily, Johanna M; Wittink, Harriet

2018-03-12

Reports on the association between aerobic capacity and walking capacity in people after stroke show disparate results. To determine (1) if the predictive validity of peak oxygen uptake (VO2peak) for walking capacity post stroke is different from that of maximal oxygen uptake (VO2max) and (2) if postural control, hemiplegic lower extremity muscle strength, age and gender distort the association between aerobic capacity and walking capacity. Cross-sectional study. General community in Utrecht, the Netherlands. Community-dwelling people more than three months after stroke. Measurement of aerobic capacity were performed with cardiopulmonary exercise testing (CPET) and differentiated between the achievement of VO2peak or VO2max. Measurement of walking capacity with the Six Minute Walk Test (6MWT), postural control with the Performance Oriented Mobility Assessment (POMA) and hemiplegic lower extremity muscle strength with the Motricity Index (MI-LE). Fifty-one out of 62 eligible participants, aged 64.7 (±12.5) years were included. Analysis of covariance (ANCOVA) showed a nonsignificant difference between the predictive validities of VO2max (N = 22, β = 0.56; 95%CI 0.12 - 0.97) and VO2peak (N = 29, β = 0.72; 95%CI 0.38 - 0.92). Multiple regression analysis of the pooled sample showed a significant decrease in the β value of VO2peak (21.6%) for the 6MWT when adding the POMA as a covariate in the association model. VO2peak remained significantly related to 6MWT after correcting for the POMA (β = 0.56 (95%CI 0.39 - 0.75)) CONCLUSIONS: The results suggest similar predictive validity of aerobic capacity for walking capacity in participants achieving VO2max compared to those only achieving VO2peak. Postural control confounds the association between aerobic capacity and walking capacity. Aerobic capacity remains a valid predictor of walking capacity. Aerobic capacity is an important factor associated with walking capacity after stroke. However, to understand this relationship, postural control needs to be measured. Both aerobic capacity and postural control may need to be addressed during interventions aiming to improve walking capacity after stroke.

The dynamics of bedrock channel adjustment: Modeling the influence of sediment supply, weathering, and lithology on channel cross-sectional and longitudinal shape

NASA Astrophysics Data System (ADS)

Wobus, C.; Tucker, G.; Anderson, R.; Kean, J.; Small, E.; Hancock, G.

2007-12-01

The cross-sectional form of a natural river channel controls the capacity of the system to carry water off a landscape, to convey sediment derived from hillslopes, and to erode its bed and banks. Numerical models that describe the response of a landscape to changes in climate or tectonics therefore require formulations that can accommodate changes in channel cross-sectional geometry through time. We have developed a 2D numerical model that computes the formation of a channel in a cohesive, detachment-limited substrate subject to steady, unidirectional flow. Boundary shear stress is calculated using a simple approximation of the flow field in which log-velocity profiles are assumed to apply along vectors that are perpendicular to the local boundary surface. The resulting model predictions for the velocity structure, peak boundary shear stress, and equilibrium channel shape compare well with the predictions of a more sophisticated but more computationally demanding ray-isovel model. For example, the mean velocities computed by the two models are consistent to within ~3%, and the predicted peak shear stress is consistent to within ~7%. The efficiency of our model makes it suitable for calculations of long-term morphologic change both in single cross-sections and in series of cross-sections arrayed downstream. For a uniform substrate, the model predicts a strong tendency toward a fixed width-to-depth ratio, regardless of gradient or discharge. The model predicts power-law relationships between width and discharge with an exponent near 2/5, and between width and gradient with an exponent near -1/5. Recent enhancements to the model include the addition of sediment, which increases the width-to-depth ratio at steady state by favoring erosion of the channel walls relative to the channel bed (the "cover effect"). Inclusion of a probability density function of discharges with a simple parameterization of weathering along channel banks leads to the formation of model strath terraces. Downstream changes in substrate erodibility or tectonic uplift rate lead to step-function changes in channel width, consistent with empirical observations. Finally, explicit inclusion of bedload transport allows channel width, gradient, and the pattern of sediment flux to evolve dynamically, allowing us to explore the response of bedrock channels to both spatial patterns of rock uplift, and temporal variations in sediment input.

X-ray relative intensities at incident photon energies across the L{sub i} (i=1–3) absorption edges of elements with 35≤Z≤92

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

Puri, Sanjiv, E-mail: sanjivpurichd@yahoo.com

The intensity ratios, I{sub Lk}/I{sub Lα1} (k=l,η,α{sub 2},β{sub 1},β{sub 2,15},β{sub 3},β{sub 4},β{sub 5,7},β{sub 6},β{sub 9,10},γ{sub 1,5},γ{sub 6,8},γ{sub 2,3},γ{sub 4}) and I{sub Lj}/I{sub Lα} (j=β,γ), have been evaluated at incident photon energies across the L{sub i} (i=1–3) absorption edge energies of all the elements with 35≤Z≤92. Use is made of what are currently considered to be more reliable theoretical data sets of different physical parameters, namely, the L{sub i} (i=1–3) sub-shell photoionization cross sections based on the relativistic Hartree–Fock–Slater (RHFS) model, the X-ray emission rates based on the Dirac–Fock model, and the fluorescence and Coster–Kronig yields based on the Dirac–Hartree–Slater model.more » In addition, the Lα{sub 1} X-ray production cross sections for different elements at various incident photon energies have been tabulated so as to facilitate the evaluation of production cross sections for different resolved L X-ray components from the tabulated intensity ratios. Further, to assist evaluation of the prominent (L{sub i}−S{sub j}) (S{sub j}=M{sub j}, N{sub j} and i=1–3, j=1–7) resonant Raman scattered (RRS) peak energies for an element at a given incident photon energy (below the L{sub i} sub-shell absorption edge), the neutral-atom electron binding energies based on the relaxed orbital RHFS calculations are also listed so as to enable identification of the RRS peaks, which can overlap with the fluorescent X-ray lines. -- Highlights: •The L X-ray relative intensities and Lα{sub 1} XRP cross sections are evaluated using physical parameters based on the IPA models. •Comparison of the intensity ratios evaluated using the DHS and DF models based photoionization cross sections is presented. •Importance of many body effects including electron exchange effects is highlighted.« less

Analysis of Classical Time-Trial Performance and Technique-Specific Physiological Determinants in Elite Female Cross-Country Skiers.

PubMed

Sandbakk, Øyvind; Losnegard, Thomas; Skattebo, Øyvind; Hegge, Ann M; Tønnessen, Espen; Kocbach, Jan

2016-01-01

The present study investigated the contribution of performance on uphill, flat, and downhill sections to overall performance in an international 10-km classical time-trial in elite female cross-country skiers, as well as the relationships between performance on snow and laboratory-measured physiological variables in the double poling (DP) and diagonal (DIA) techniques. Ten elite female cross-country skiers were continuously measured by a global positioning system device during an international 10-km cross-country skiing time-trial in the classical technique. One month prior to the race, all skiers performed a 5-min submaximal and 3-min self-paced performance test while roller skiing on a treadmill, both in the DP and DIA techniques. The time spent on uphill (r = 0.98) and flat (r = 0.91) sections of the race correlated most strongly with the overall 10-km performance (both p < 0.05). Approximately 56% of the racing time was spent uphill, and stepwise multiple regression revealed that uphill time explained 95.5% of the variance in overall performance (p < 0.001). Distance covered during the 3-min roller-skiing test and body-mass normalized peak oxygen uptake (VO2peak) in both techniques showed the strongest correlations with overall time-trial performance (r = 0.66-0.78), with DP capacity tending to have greatest impact on the flat and DIA capacity on uphill terrain (all p < 0.05). Our present findings reveal that the time spent uphill most strongly determine classical time-trial performance, and that the major portion of the performance differences among elite female cross-country skiers can be explained by variations in technique-specific aerobic power.

Analysis of Classical Time-Trial Performance and Technique-Specific Physiological Determinants in Elite Female Cross-Country Skiers

PubMed Central

Sandbakk, Øyvind; Losnegard, Thomas; Skattebo, Øyvind; Hegge, Ann M.; Tønnessen, Espen; Kocbach, Jan

2016-01-01

The present study investigated the contribution of performance on uphill, flat, and downhill sections to overall performance in an international 10-km classical time-trial in elite female cross-country skiers, as well as the relationships between performance on snow and laboratory-measured physiological variables in the double poling (DP) and diagonal (DIA) techniques. Ten elite female cross-country skiers were continuously measured by a global positioning system device during an international 10-km cross-country skiing time-trial in the classical technique. One month prior to the race, all skiers performed a 5-min submaximal and 3-min self-paced performance test while roller skiing on a treadmill, both in the DP and DIA techniques. The time spent on uphill (r = 0.98) and flat (r = 0.91) sections of the race correlated most strongly with the overall 10-km performance (both p < 0.05). Approximately 56% of the racing time was spent uphill, and stepwise multiple regression revealed that uphill time explained 95.5% of the variance in overall performance (p < 0.001). Distance covered during the 3-min roller-skiing test and body-mass normalized peak oxygen uptake (VO2peak) in both techniques showed the strongest correlations with overall time-trial performance (r = 0.66–0.78), with DP capacity tending to have greatest impact on the flat and DIA capacity on uphill terrain (all p < 0.05). Our present findings reveal that the time spent uphill most strongly determine classical time-trial performance, and that the major portion of the performance differences among elite female cross-country skiers can be explained by variations in technique-specific aerobic power. PMID:27536245

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

Younes, W; Britt, H C; Wilhelmy, J B

The purpose of this note is to combine existing information on the {sup 237}U(n,f) cross section to determine if some consistency can be obtained for the neutron induced fission excitation of {sup 237}U. The neutron induced fission cross section of the 6.8 day {sup 237}U was measured directly by McNally et al. in 1968 using the Pommard nuclear device test. At the same time critical assembly measurements were done at Los Alamos using the Flattop assembly. A previous measurement was also made at LASL in 1954 with two different neutron sources, each peaked near 200 keV. The results were 0.66more » {+-} 0.10 b and 0.70 {+-} 0.07 b for the (n,f) cross section. More recently Younes and Britt have reanalyzed direct reaction charged particle data of Cramer and Britt that had determined the fission probability of the {sup 238}U compound nucleus as a function of nuclear excitation energy. They have combined fission probabilities with calculated neutron absorption cross sections, including corrections for the differences in angular momentum between the direct and neutron induced reactions. From this analysis they have extracted equivalent {sup 237}U(n,f) cross sections. The technique for extracting surrogate (n,f) cross sections from (t,pf) data has been demonstrated in a recent publication for the test case {sup 235}U(n,f). In addition to this experimental information, Lynn and Hayes have recently done a new theoretical study of the fission cross sections for a series of isotopes in this region. A summary plot of the data is shown in Fig. 1. Below 0.5 MeV the McNally, Cowan, and Younes-Britt results are in reasonable agreement. The average cross section in the Younes-Britt results, for En = 0.1 to 0.4 MeV, is 0.80 times the McNally values which is well within the errors of the McNally experiment. Above 0.5 MeV the McNally results diverge toward higher values. It should be noted that this divergence begins approximately at the {sup 237}Np threshold and that {sup 237}Np is the daughter of the 6.8 day {sup 237}U decay.« less

Numerical and experimental investigations of dependence of photoacoustic signals from gold nanoparticles on the optical properties

NASA Astrophysics Data System (ADS)

Okawa, Shinpei; Hirasawa, Takeshi; Sato, Ryota; Kushibiki, Toshihiro; Ishihara, Miya; Teranishi, Toshiharu

2018-06-01

Gold nanoparticles (AuNPs) are used as a contrast agent of the photoacoustic (PA) imaging. The efficiency of AuNPs has been discussed with the absorption cross section. However, the effects of the scattering of the light by AuNPs and surrounding medium on the PA signal from AuNPs have not been discussed. The PA signals from the aqueous solution of AuNPs were examined in the numerical simulation and the experiment. In the numerical simulation, the absorption and scattering cross sections of spherical and polyhedral AuNPs were calculated by Mie theory and discrete dipole approximation. Monte Carlo simulation calculated the absorbed light energy in the aqueous solution of AuNPs. Based on the PA wave equation, the PA signals were simulated. In the experiment, the PA signal from the aqueous solution of AuNP was measured by use of a piezoelectric film and a Q-switched Nd:YAG laser operated at 532 nm. The results of the numerical simulation and the experiment agreed well. In the numerical simulation and the experiment, a single Au nanocube with 50-nm edge generated the peak value of the PA signal significantly. It was approximately 350 times and twice as large as the peak values of the spherical AuNPs with 10- and 50-nm diameters, respectively. The peak value of the PA signal depended on both the absorption and scattering coefficients of the AuNPs and the surrounding medium. The peak value increased with the scattering coefficient in a quadratic manner. The character of the temporal profile of the PA signal such as full width at half maximum depended on the scattering coefficient of the AuNPs.

Examination of sustained gait speed during extended walking in individuals with chronic stroke.

PubMed

Altenburger, Peter A; Dierks, Tracy A; Miller, Kristine K; Combs, Stephanie A; Van Puymbroeck, Marieke; Schmid, Arlene A

2013-12-01

To determine if individuals with chronic stroke were able to sustain their peak gait speed during the 6-minute walk test (6MWT), and to explore this sustainability across community ambulation potential subgroups. Prospective cross-sectional study. University-based research laboratory, hospitals, and stroke support groups. A sample of individuals with chronic stroke (N=48) completed a series of questionnaires and physical outcome measures, including gait mat assessment, during a single visit. Not applicable; 1-time cross-sectional data collection. During the 6MWT, we measured peak gait speed and end gait speed to assess sustainability, along with beginning gait speed, total distance walked, and rating of perceived exertion. We also assessed maximum gait speed during the 10-meter walk test (10MWT). Finally, we examined these gait outcomes across the subgroups. During the 6MWT, peak gait speed declined from .89m/s (SD=.38) to an end speed of .82m/s (SD=.36), whereas perceived exertion increased from 7.7 (SD=2.6) to 11.8 (SD=3.6). This peak gait speed was slower than the 10MWT maximum speed of 1.06m/s (SD=.51), but faster than the 6MWT beginning speed of .81m/s (SD=.34). The unlimited community ambulator subgroup was the primary contributor to sustainability differences. Predicting community ambulation potential based on the discrete gait speed from the 10MWT and endurance based on the average from the 6MWT might be incomplete if gait speed sustainability is not also assessed. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Numerical and experimental investigations of dependence of photoacoustic signals from gold nanoparticles on the optical properties

NASA Astrophysics Data System (ADS)

Okawa, Shinpei; Hirasawa, Takeshi; Sato, Ryota; Kushibiki, Toshihiro; Ishihara, Miya; Teranishi, Toshiharu

2018-04-01

Gold nanoparticles (AuNPs) are used as a contrast agent of the photoacoustic (PA) imaging. The efficiency of AuNPs has been discussed with the absorption cross section. However, the effects of the scattering of the light by AuNPs and surrounding medium on the PA signal from AuNPs have not been discussed. The PA signals from the aqueous solution of AuNPs were examined in the numerical simulation and the experiment. In the numerical simulation, the absorption and scattering cross sections of spherical and polyhedral AuNPs were calculated by Mie theory and discrete dipole approximation. Monte Carlo simulation calculated the absorbed light energy in the aqueous solution of AuNPs. Based on the PA wave equation, the PA signals were simulated. In the experiment, the PA signal from the aqueous solution of AuNP was measured by use of a piezoelectric film and a Q-switched Nd:YAG laser operated at 532 nm. The results of the numerical simulation and the experiment agreed well. In the numerical simulation and the experiment, a single Au nanocube with 50-nm edge generated the peak value of the PA signal significantly. It was approximately 350 times and twice as large as the peak values of the spherical AuNPs with 10- and 50-nm diameters, respectively. The peak value of the PA signal depended on both the absorption and scattering coefficients of the AuNPs and the surrounding medium. The peak value increased with the scattering coefficient in a quadratic manner. The character of the temporal profile of the PA signal such as full width at half maximum depended on the scattering coefficient of the AuNPs.

Development of Ethnic, Racial, and National Prejudice in Childhood and Adolescence: A Multinational Meta-Analysis of Age Differences

ERIC Educational Resources Information Center

Raabe, Tobias; Beelmann, Andreas

2011-01-01

This meta-analysis summarizes 113 research reports worldwide (121 cross-sectional and 7 longitudinal studies) on age differences in ethnic, racial, or national prejudice among children and adolescents. Overall, results indicated a peak in prejudice in middle childhood (5-7 years) followed by a slight decrease until late childhood (8-10 years). In…

Reentry heating analysis of space shuttle with comparison of flight data

NASA Technical Reports Server (NTRS)

Gong, L.; Quinn, R. D.; Ko, W. L.

1982-01-01

Surface heating rates and surface temperatures for a space shuttle reentry profile were calculated for two wing cross sections and one fuselage cross section. Heating rates and temperatures at 12 locations on the wing and 6 locations on the fuselage are presented. The heating on the lower wing was most severe, with peak temperatures reaching values of 1240 C for turbulent flow and 900 C for laminar flow. For the fuselage, the most severe heating occured on the lower glove surface where peak temperatures of 910 C and 700 C were calculated for turbulent flow and laminar flow, respectively. Aluminum structural temperatures were calculated using a finite difference thermal analyzer computer program, and the predicted temperatures are compared to measured flight data. Skin temperatures measured on the lower surface of the wing and bay 1 of the upper surface of the wing agreed best with temperatures calculated assuming laminar flow. The measured temperatures at bays two and four on the upper surface of the wing were in quite good agreement with the temperatures calculated assuming separated flow. The measured temperatures on the lower forward spar cap of bay four were in good agreement with values predicted assuming laminar flow.

Crystal growth, polarized spectra, and laser performance of Yb:CaGdAlO4 crystal

NASA Astrophysics Data System (ADS)

Di, J. Q.; Xu, X. D.; Xia, C. T.; Zheng, L. H.; Aka, G.; Yu, H. H.; Sai, Q. L.; Guo, X. Y.; Zhu, L.

2016-04-01

In this paper, the crystal growth, polarized spectra, and laser performance of Yb:CaGdAlO4 crystal were reported. The segregation coefficient of Yb3+ ions was calculated to be 0.47. The cell parameters were determined to be a  =  b  =  0.3658 nm, c  =  1.1985 nm. The peak absorption cross-section was calculated to be 2.65  ×  10-20 cm2 at 979 nm and the peak stimulated emission cross-section was 2.23  ×  10-20 cm2 at 980 nm for the π polarization. The continuous-wave (CW) laser operations of uncoated Yb:CaGdAlO4 crystals with 5  ×  5  ×  3 mm3 in size were demonstrated. A maximum output power of 1.6 W at 1048 nm was obtained with a slope efficiency of 28%. The results show that Yb:CaGdAlO4 crystal is a promising laser medium.

Electronic state and photoionization cross section of a single dopant in GaN/InGaN core/shell quantum dot under magnetic field and hydrostatic pressure

NASA Astrophysics Data System (ADS)

Aouami, A. El; Feddi, E.; Talbi, A.; Dujardin, F.; Duque, C. A.

2018-06-01

In this study, we have investigated the simultaneous influence of magnetic field combined to the hydrostatic pressure and the geometrical confinement on the behavior of a single dopant confined in GaN/InGaN core/shell quantum dots. Within the scheme of the effective-mass approximation, the eigenvalues equation has solved by using the variational method with one-parameter trial wavefunctions. Variation of the ground state binding energy of the single dopant is determined according to the magnetic field and hydrostatic pressure for several dimensions of the heterostructure. The results show that the binding energy is strongly dependent on the core/shell sizes, the magnetic field, and the hydrostatic pressure. The analysis of the photoionization cross section, corresponding to optical transitions associated to the first donor energy level and the conduction band, shows clearly that the reduction of the dot dimensions and/or the simultaneous influences of applied magnetic field, combined to the hydrostatic pressure strength, cause a shift in resonance peaks towards the higher energies with important variations in the magnitude of the resonant peaks.

Growth and spectral properties of Tm:BaY2F8 crystals with different Tm3+ concentration

NASA Astrophysics Data System (ADS)

Liu, Wang; Li, Chun; Xu, Jialin; Zhou, Yao; Xie, Huishuang; Gao, Meiling; Yin, Ru; Zheng, Dongyang; Lin, Hai; Liu, Jinghe; Zeng, Fanming

2016-01-01

Tm3+:BaY2F8 (Tm:BYF) laser crystals with different doping concentrations were successfully grown by Czochralski method. The optimal growth parameters obtained are as follows: the pulling rate is 0.5 mm/h; the rotation speed is 5 rpm; the cooling rate is 10°C/h. Phase composition, absorption spectra, and fluorescence properties of crystals were studied by XRD and spectral methods. XRD analysis indicates that the crystal belongs to monoclinic system with the C2/ m space group. The lattice parameters were calculated and the anisotropy of the crystals was studied, confirming that the a axis is the best growth direction. The absorption peaks around 790 nm became larger with increase of Tm3+ concentration. The cross section of 15% Tm:BYF crystal around 791 nm is 9.47 × 10-21 cm2. The 10% Tm:BYF crystal has the strongest emission peak around 1879.6 nm with the FWHM of 79 nm and the emission cross-section of 2.13 × 10-21 cm2, which is favorable for the 1.88 μm laser output.

The line-locking hypothesis, absorption by intervening galaxies, and the z = 1.95 peak in redshifts

NASA Technical Reports Server (NTRS)

Burbidge, G.

1978-01-01

The controversy over whether the absorption spectrum in QSOs is intrinsic or extrinsic is approached with attention to the peak of redshifts at z = 1.95. Also considered are the line-locking and the intervening galaxy hypotheses. The line locking hypothesis is based on observations that certain ratios found in absorption line QSOs are preferred, and leads inevitably to the conclusion that the absorption line systems are intrinsic. The intervening galaxy hypothesis is based on absorption redshifts resulting from given absorption cross-sections of galactic clusters and the intergalactic medium, and would lead to the theoretical conclusion that most QSOs show strong absorption, a conclusion which is not supported by empirical data. The 1.95 peak, on the other hand, is most probably an intrinsic property of QSOs. The peak is enhanced by redshift, and it is noted that both an emission and an absorption redshift peak are seen at 1.95.

Rib Geometry Explains Variation in Dynamic Structural Response: Potential Implications for Frontal Impact Fracture Risk.

PubMed

Murach, Michelle M; Kang, Yun-Seok; Goldman, Samuel D; Schafman, Michelle A; Schlecht, Stephen H; Moorhouse, Kevin; Bolte, John H; Agnew, Amanda M

2017-09-01

The human thorax is commonly injured in motor vehicle crashes, and despite advancements in occupant safety rib fractures are highly prevalent. The objective of this study was to quantify the ability of gross and cross-sectional geometry, separately and in combination, to explain variation of human rib structural properties. One hundred and twenty-two whole mid-level ribs from 76 fresh post-mortem human subjects were tested in a dynamic frontal impact scenario. Structural properties (peak force and stiffness) were successfully predicted (p < 0.001) by rib cross-sectional geometry obtained via direct histological imaging (total area, cortical area, and section modulus) and were improved further when utilizing a combination of cross-sectional and gross geometry (robusticity, whole bone strength index). Additionally, preliminary application of a novel, adaptive thresholding technique, allowed for total area and robusticity to be measured on a subsample of standard clinical CT scans with varied success. These results can be used to understand variation in individual rib response to frontal loading as well as identify important geometric parameters, which could ultimately improve injury criteria as well as the biofidelity of anthropomorphic test devices (ATDs) and finite element (FE) models of the human thorax.

Rib Geometry Explains Variation in Dynamic Structural Response: Potential Implications for Frontal Impact Fracture Risk

PubMed Central

Murach, Michelle M.; Kang, Yun-Seok; Goldman, Samuel D.; Schafman, Michelle A.; Schlecht, Stephen H.; Moorhouse, Kevin; Bolte, John H.; Agnew, Amanda M.

2018-01-01

The human thorax is commonly injured in motor vehicle crashes, and despite advancements in occupant safety rib fractures are highly prevalent. The objective of this study was to quantify the ability of gross and cross-sectional geometry, separately and in combination, to explain variation of human rib structural properties. One hundred and twenty-two whole mid-level ribs from 76 fresh post-mortem human subjects were tested in a dynamic frontal impact scenario. Structural properties (peak force and stiffness) were successfully predicted (p<0.001) by rib cross-sectional geometry obtained via direct histological imaging (total area, cortical area, and section modulus) and were improved further when utilizing a combination of cross-sectional and gross geometry (robusticity, whole bone strength index). Additionally, preliminary application of a novel, adaptive thresholding technique, allowed for total area and robusticity to be measured on a subsample of standard clinical CT scans with varied success. These results can be used to understand variation in individual rib response to frontal loading as well as identify important geometric parameters, which could ultimately improve injury criteria as well as the biofidelity of anthropomorphic test devices (ATDs) and finite element (FE) models of the human thorax. PMID:28547660

Thermoluminescence kinetics of pyrite (FeS2)

NASA Astrophysics Data System (ADS)

Silverman, A. N.; Levy, P. W.; Kierstead, J. A.

Thermoluminescence of pyrite (FeS2) was investigated to study the kinetics of single peak glow curves. The material used normally exhibits one large and four small peaks. However a glow curve can be obtained with only the large single peak that is suitable for testing thermoluminescence kinetics. Glow curves from aliquots of a single natural pyrite crystal studied in detail contain two low intensity thermoluminescence (TL) peaks at approximately 90 and 250 C, and two chemiluminescence (CL) peaks at approximately 350 and 430 C. The CL peaks are largely removable by initially heating the sample chamber under vacuum, pumping through liquid nitrogen traps, and recording glow curves immediately after helium is introduced, procedures which reduce system contaminants that react with pyrite. The shape, the variation of the temperature of the peak maximum (T(sub max)) with dose, and the retrapping to recombination cross section ratio (sigma) of the large 250 C peak are better described by the general one trap (GOT) kinetic equation, the basic equation from which the 1st and 2nd order kinetic equations are obtained as special cases, than by the 1st and 2nd order equations.

Measurements of cross sections for the 209Bi(n, 4n) reaction by using high energy neutrons with continuous energy spectra

NASA Astrophysics Data System (ADS)

Min, Kyung Joo; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Myung, Hyunjeong; Shim, Chungbo; Shin, Jae Won; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

2017-09-01

We measured 209Bi(n, 4n) cross sections at neutron energies En = 29.8 ± 1.8 MeV and En = 34.8 ± 1.8 MeV. Bismuth oxide samples were irradiated with the neutrons produced by impinging 30, 35 and 40 MeV proton beams on a 1.05 cm thick beryllium target, where the proton beams were from the MC-50 Cyclotron of Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux for each proton beam energy Ep, ΦEp(En), has a broad spectrum with respect to En. By taking the difference in the neutron fluxes, the difference spectra, Φ40(En) -Φ35(En) and Φ35(En) -Φ30(En), are obatined and found to be peaked at En = 29.8 and 34.8 MeV, respectively, with a width of about 3.6 MeV. By making use of this observation and employing the TENDL-2009 library we could extract the 209Bi(n, 4n)206Bi cross sections at the aforementioned neutron energies.

Calculations of total electron-impact ionization cross sections for Fluoroketone C5F10O and Fluoronitrile C4F7N using modified Deutsch-Märk formula

NASA Astrophysics Data System (ADS)

Xiong, Jiayu; Li, Xingwen; Wu, Jian; Guo, Xiaoxue; Zhao, Hu

2017-11-01

Both fluoroketone C5F10O and fluoronitrile C4F7N are promising substitute gases for SF6. The electron-impact ionization cross sections for these two gases are calculated using the Deutsch-Märk (DM) formula and its modified method. The necessary molecular geometry optimization and electron population were determined by ab initio calculation, which was performed with quantum chemistry code. The level of calculation, including the theoretical method and basis-set, are carefully determined. To eliminate the drawbacks of the DM formula, a modified DM formula is set in this paper. The modified DM formula, of which the weighting factors are changed, has a better agreement with the experimental data on both the peak and shape of the cross-section curves. The results calculated by DM formula and modified DM formula are given as references to fill in gaps in further research into C5F10O and C4F7N.

Contractile properties of rat, rhesus monkey, and human type I muscle fibers

NASA Technical Reports Server (NTRS)

Widrick, J. J.; Romatowski, J. G.; Karhanek, M.; Fitts, R. H.

1997-01-01

It is well known that skeletal muscle intrinsic maximal shortening velocity is inversely related to species body mass. However, there is uncertainty regarding the relationship between the contractile properties of muscle fibers obtained from commonly studied laboratory animals and those obtained from humans. In this study we determined the contractile properties of single chemically skinned fibers prepared from rat, rhesus monkey, and human soleus and gastrocnemius muscle samples under identical experimental conditions. All fibers used for analysis expressed type I myosin heavy chain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Allometric coefficients for type I fibers from each muscle indicated that there was little change in peak tension (force/fiber cross-sectional area) across species. In contrast, both soleus and gastrocnemius type I fiber maximal unloaded shortening velocity (Vo), the y-intercept of the force-velocity relationship (Vmax), peak power per unit fiber length, and peak power normalized for fiber length and cross-sectional area were all inversely related to species body mass. The present allometric coefficients for soleus fiber Vo (-0.18) and Vmax (-0.11) are in good agreement with published values for soleus fibers obtained from common laboratory and domesticated mammals. Taken together, these observations suggest that the Vo of slow fibers from quadrupeds and humans scale similarly and can be described by the same quantitative relationships. These findings have implications in the design and interpretation of experiments, especially those that use small laboratory mammals as a model of human muscle function.

Wheelchair-specific fitness of persons with a long-term spinal cord injury: cross-sectional study on effects of time since injury and physical activity level.

PubMed

de Groot, Sonja; van der Scheer, Jan W; Bakkum, Arjan J T; Adriaansen, Jacinthe J E; Smit, Christof A; Dijkstra, Catja; Post, Marcel W M; van der Woude, Lucas H V

2016-01-01

To study the impact of time since injury (TSI) and physical activity (PA) on fitness of persons with spinal cord injury (SCI). Cross-sectional study. Persons with SCI (N = 158) in three TSI strata: 10-19, 20-29 and ≥30 years after SCI and divided in an active and inactive group. Fitness [peak power output (POpeak) and peak oxygen uptake (VO2peak)] was assessed. In persons with tetraplegia, no significant relationship was found between TSI and fitness after controlling for confounders, while a higher activity level was related to a higher POpeak in this group. Active people with tetraplegia also showed less decline in POpeak with an increase in TSI compared to inactive people. In persons with paraplegia, after controlling for confounders, it was shown that TSI had a negative effect on POpeak, while PA was not significantly associated with fitness in people with paraplegia. In people with paraplegia, fitness was significantly lower in those with a longer TSI. Persons with a long TSI might need more attention to remain fit and PA might be an important element in that respect as shown by the results of the group with a tetraplegia. Wheelchair-specific fitness seems to diminish over time after paraplegia. An active lifestyle is related to wheelchair-specific fitness in persons with tetraplegia. Prevention of long-term deconditioning is very important.

Longitudinal versus cross-sectional methodology for estimating the economic burden of breast cancer: a pilot study.

PubMed

Mullins, C Daniel; Wang, Junling; Cooke, Jesse L; Blatt, Lisa; Baquet, Claudia R

2004-01-01

Projecting future breast cancer treatment expenditure is critical for budgeting purposes, medical decision making and the allocation of resources in order to maximise the overall impact on health-related outcomes of care. Currently, both longitudinal and cross-sectional methodologies are used to project the economic burden of cancer. This pilot study examined the differences in estimates that were obtained using these two methods, focusing on Maryland, US Medicaid reimbursement data for chemotherapy and prescription drugs for the years 1999-2000. Two different methodologies for projecting life cycles of cancer expenditure were considered. The first examined expenditure according to chronological time (calendar quarter) for all cancer patients in the database in a given quarter. The second examined only the most recent quarter and constructed a hypothetical expenditure life cycle by taking into consideration the number of quarters since the respective patient had her first claim. We found different average expenditures using the same data and over the same time period. The longitudinal measurement had less extreme peaks and troughs, and yielded average expenditure in the final period that was 60% higher than that produced using the cross-sectional analysis; however, the longitudinal analysis had intermediate periods with significantly lower estimated expenditure than the cross-sectional data. These disparate results signify that each of the methods has merit. The longitudinal method tracks changes over time while the cross-sectional approach reflects more recent data, e.g. current practice patterns. Thus, this study reiterates the importance of considering the methodology when projecting future cancer expenditure.

Peak high-frequency HRV and peak alpha frequency higher in PTSD.

PubMed

Wahbeh, Helané; Oken, Barry S

2013-03-01

Posttraumatic stress disorder (PTSD) is difficult to treat and current PTSD treatments are not effective for all people. Despite limited evidence for its efficacy, some clinicians have implemented biofeedback for PTSD treatment. As a first step in constructing an effective biofeedback treatment program, we assessed respiration, electroencephalography (EEG) and heart rate variability (HRV) as potential biofeedback parameters for a future clinical trial. This cross-sectional study included 86 veterans; 59 with and 27 without PTSD. Data were collected on EEG measures, HRV, and respiration rate during an attentive resting state. Measures were analyzed to assess sensitivity to PTSD status and the relationship to PTSD symptoms. Peak alpha frequency was higher in the PTSD group (F(1,84) = 6.14, p = 0.01). Peak high-frequency HRV was lower in the PTSD group (F(2,78) = 26.5, p < 0.00005) when adjusting for respiration rate. All other EEG and HRV measures and respiration were not different between groups. Peak high-frequency HRV and peak alpha frequency are sensitive to PTSD status and may be potential biofeedback parameters for future PTSD clinical trials.

Peak High-Frequency HRV and Peak Alpha Frequency Higher in PTSD

PubMed Central

Oken, Barry S.

2012-01-01

Posttraumatic stress disorder (PTSD) is difficult to treat and current PTSD treatments are not effective for all people. Despite limited evidence for its efficacy, some clinicians have implemented biofeedback for PTSD treatment. As a first step in constructing an effective biofeedback treatment program, we assessed respiration, electroencephalography (EEG) and heart rate variability (HRV) as potential biofeedback parameters for a future clinical trial. This cross-sectional study included 86 veterans; 59 with and 27 without PTSD. Data were collected on EEG measures, HRV, and respiration rate during an attentive resting state. Measures were analyzed to assess sensitivity to PTSD status and the relationship to PTSD symptoms. Peak alpha frequency was higher in the PTSD group (F(1,84) = 6.14, p = 0.01). Peak high-frequency HRV was lower in the PTSD group (F(2,78) = 26.5, p<0.00005) when adjusting for respiration rate. All other EEG and HRV measures and respiration were not different between groups. Peak high-frequency HRV and peak alpha frequency are sensitive to PTSD status and may be potential biofeedback parameters for future PTSD clinical trials. PMID:23178990

Generation and amplification of sub-THz radiation in a rare gases plasma formed by a two-color femtosecond laser pulse

NASA Astrophysics Data System (ADS)

Bogatskaya, A. V.; Volkova, E. A.; Popov, A. M.

2018-06-01

A new approach to constructing the source of radiation in the sub-THz frequency range is discussed. It is based on the strong-field ionization of heavy rare gases with Ramsauer minimum in the transport cross-section by a two-color () femtosecond laser pulse. Then a four-photon nonlinear process ( are the frequencies from the spectral width of the pulse with frequency ω, and is the frequency from the spectral width of the second harmonic 2ω) with a transition to the initial state results in a low-frequency spontaneous emission that can be amplified in the strongly nonequilibrium laser plasma if the position of the photoelectron peaks is located in the region of growing energy transport cross-section.

Variation of froude number with discharge for large-gradient steams

USGS Publications Warehouse

Wahl, Kenneth L.; ,

1993-01-01

Under chemical-control conditions, the Froude number (f) for a cross-section can be approximated as a function of the ratio R2/ 3/d 1/2 , where R is the hydraulic radius and d is the average depth. For cross sections where the ratio increases with increasing depth, F can also increase with depth Current-meter measurement data for 433 streamflow gaging stations in Colorado were reviewed, and 62 stations were identified at which F increases with depth of flow. Data for four streamflow gaging stations are presented. In some cases, F approaches 1 as the discharge approaches the magnitude of the median annual peak discharge. The data also indicate that few actual current meter measurement have been made at the large discharges where velocities can be supercritical.

First results from gamma ray diagnostics in EAST Tokamak

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

Zhou, R. J.; Hu, L. Q.; Zhong, G. Q., E-mail: gqzhong@ipp.ac.cn

2016-11-15

Gamma ray diagnostics has been developed in the EAST tokamak recently. Six BGO scintillator detectors are arranged on the down-half cross-section and pointed at the up-half cross-section of plasma, with space resolution about 15 cm and energy range from 0.3 MeV to 6 MeV. Three main gamma ray peaks in the energy spectra have been observed and are identified as the results of nuclear reactions {sup 207}Pb(n, n′){sup 207m}Pb, H(n, γ) D, and D(p, γ){sup 3}He, respectively. Upgrading of the system is in progress by using LaBr3(Ce) scintillator, fast photo-multiplier tubes, and a fully digital data acquisition system based onmore » high sample frequency digitizers with digital pulse processing algorithms.« less

Variable Depth Bragg Peak Method for Single Event Effects Testing

NASA Technical Reports Server (NTRS)

Buchner, S.; Kanyogoro, N.; Foster, C.; O'Neill, P.

2011-01-01

Traditionally, accelerator SEE testing is accomplished by removing the tops of packages so that the IC chips are accessible to heavy ions. However, ICs in some advanced packages cannot be de-lidded so a different approach is used that involves grinding and/or chemically etching away part of the package and the chip from the back side. The parts are then tested from the back side with ions having sufficient range to reach the sensitive volume. More recently, the entire silicon substrate in an SOI/SRAM was removed, making it possible to use low-energy ions with shorter ranges. Where removal of part of the package is not possible, facilities at Michigan State, NASA Space Radiation Laboratory, GANIL (France) and GSI (Germany) offer high-energy heavy ions with long ranges so that the ions can reach the devices' sensitive volumes without much change in the LET. Unfortunately, a run will typically involve only one ion species having a single energy and LET due to the long time it takes to tune a new energy. The Variable Depth Bragg Peak (VDBP) method is similar to the above method in that it involves the use of high-energy heavy ions that are able to pass through the packaging material and reach the device, obviating the need to remove the package. However, the method provides a broad range of LETs from a single ion by inserting degraders in the beam that modify the ion energy and, therefore, the LET. The crux of the method involves establishing a fiduciary point for degrader thickness, i.e., where the Bragg peak is located precisely at the sensitive volume in the device, for which the measured SEU cross-section and the ion LET are both also maxima and can be calculated using a Monte-Carlo program, TRIM. Once the fiduciary point has been established, calibrated high density polyethylene (HDPE) degraders are inserted into or removed from the beam to vary the ion LET at the device in a known manner. After each change of degrader thickness, the SEU cross-section is measured and the corresponding LET calculated from the change in degrader thickness. That information is used to generate a plot of cross-section as a function of ion LET. The advantages of this approach are that the part does not have to be de-lidded and a broad range of LETs is available from a single heavy ion without having to go to non-normal angles of incidence to change the "effective" LET. As we will show, it is possible to obtain an entire curve of cross-section versus LET using just two or three ions. Fig. 1 shows curves of cross-section vs LET for a Freescale 4 Mbit SOI/SRAM measured at the 88" Cyclotron at Berkeley and at NSRL. The open symbols are the data obtained from Berkeley for top-side and back-side irradiation. The solid data points are for the data obtained at NSRL using a device for which the package was intact. The data are for Iron and Gold and cover a range of LETs from 4 MeV.cm2/mg to 84 MeV.cm2/mg. The agreement between the data obtained from Berkeley and from NSRL is excellent, demonstrating that the VDBP method is capable of providing accurate values of cross-section versus LET, at least for the 4 Mbit SRAM. Details of the technique will be included in the final presentation.

Fluvial sandstone reservoirs of Travis Peak (Hosston) Formation, east Texas basin

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

Tye, R.S.

1989-03-01

Gas production (7.2 billion ft/sup 3/) from low-permeability sandstones in the Travis Peak Formation, North Appleby field, Nacogdoches County, Texas, is enhanced through massive hydraulic fracturing of stacked sandstones that occur at depths between 8000 and 10,000 ft. stratigraphic reservoirs were formed in multilateral tabular sandstones owing to impermeable mudstone interbeds that encase blocky to upward-fining sandstones. Pervasive quartz cement in the sandstones decreases porosity and permeability and augments the reservoir seal. Subsurface data indicate that much of this 2000-ft thick section represents aggradation of alluvial-valley deposits. Multiple channel belts form a network of overlapping, broad, tabular sandstones having thickness-to-widthmore » ratios of 1:850 (8-44 ft thick; widths exceed 4-5 mi). Six to eight channel belts, each containing 80-90% medium to fine-grained sandstone, can occupy a 200-ft thick interval. In a vertical sequence through one channel belt sandstone, basal planar cross-bedding grades upward into thinly interbedded sets of planar cross-beds and ripple cross-lamination. Clay-clast conglomerates line scoured channel bases. Adjacent to the channels, interbedded mudstones accumulated in well-drained swamps and lakes. Poorly sorted sandstones represent overbank deposition (crevasse splays and lacustrine deltas). During Travis Peak deposition, fluvial styles evolved from dominantly braided systems near the base of the formation to more mud-rich, meandering systems at the top.« less

Peak expiratory flow rate in handloom weavers.

PubMed

Tiwari, R R; Zodpey, S P; Deshpande, S G; Vasudeo, N D

1998-04-01

The present cross-sectional study with a comparison group was carried out to investigate peak expiratory flow rate (PEFR) in handloom weavers and to study relationship between reduction in PEFR with age, smoking, duration of cotton dust exposure and respiratory morbidity. This study include 319 handloom weavers and equal number of individuals (group matched for age and pair matched for sex) in comparison group. The decline in PEFR was significantly associated with advancing age, longer duration of exposure to cotton dust, tobacco smoking and presence of respiratory morbidity on univariate analysis, whereas on multivariate analysis longer duration of exposure to cotton dust and tobacco smoking was found to be non significant.

Differential Cross Section and Photon-Beam Asymmetry for the γ → p → π-Δ++(1232 ) Reaction at Forward π- Angles for Eγ=1.5 -2.95 GeV

NASA Astrophysics Data System (ADS)

Kohri, H.; Shiu, S. H.; Chang, W. C.; Yanai, Y.; Ahn, D. S.; Ahn, J. K.; Chen, J. Y.; Daté, S.; Ejiri, H.; Fujimura, H.; Fujiwara, M.; Fukui, S.; Gohn, W.; Hicks, K.; Hosaka, A.; Hotta, T.; Hwang, S. H.; Imai, K.; Ishikawa, T.; Joo, K.; Kato, Y.; Kon, Y.; Lee, H. S.; Maeda, Y.; Mibe, T.; Miyabe, M.; Morino, Y.; Muramatsu, N.; Nakano, T.; Nakatsugawa, Y.; Nam, S. i.; Niiyama, M.; Noumi, H.; Ohashi, Y.; Ohta, T.; Oka, M.; Parker, J. D.; Rangacharyulu, C.; Ryu, S. Y.; Sawada, T.; Shimizu, H.; Strokovsky, E. A.; Sugaya, Y.; Sumihama, M.; Tsunemi, T.; Uchida, M.; Ungaro, M.; Wang, S. Y.; Yosoi, M.; LEPS Collaboration

2018-05-01

Differential cross sections and photon-beam asymmetries for the γ → p →π-Δ++(1232 ) reaction have been measured for 0.7

On Dark Peaks and Missing Mass: A Weak-Lensing Mass Reconstruction of the Merging Cluster System A520

NASA Technical Reports Server (NTRS)

Clowe, Douglas; Markevitch, Maxim; Bradac, Marusa; Gonzalez, Anthony H.; Chung, Sun Mi

2012-01-01

Merging clusters of galaxies are unique in their power to directly probe and place limits on the self-interaction cross-section of dark matter. Detailed observations of several merging clusters have shown the intracluster gas to be displaced from the centroids of dark matter and galaxy density by ram pressure, while the latter components are spatially coincident, consistent with collisionless dark matter. This has been used to place upper limits on the dark matter particle self-interaction cross-section of order 1 sq cm/g. The cluster A520 has been seen as a possible exception. We revisit A520 presenting new Hubble Space Telescope Advanced Camera for Surveys mosaic images and a Magellan image set. We perform a detailed weak-lensing analysis and show that the weak-lensing mass measurements and morphologies of the core galaxy-filled structures are mostly in good agreement with previous works. There is, however, one significant difference: We do not detect the previously claimed "dark core" that contains excess mass with no significant galaxy overdensity at the location of the X-ray plasma. This peak has been suggested to be indicative of a large self-interaction cross-section for dark matter (at least approx 5alpha larger than the upper limit of 0.7 sq cm/g determined by observations of the Bullet Cluster). We find no such indication and instead find that the mass distribution of A520, after subtraction of the X-ray plasma mass, is in good agreement with the luminosity distribution of the cluster galaxies.We conclude that A520 shows no evidence to contradict the collisionless dark matter scenario.

Fourier Transform Ultraviolet Spectroscopy of the A Pi-2(3/2) Direct Current X Pi-2(3/2) Transition of BrO

NASA Technical Reports Server (NTRS)

Wilmouth, David M.; Hanisco, Thomas F.; Donahue, Neil M.; Anderson, James G.

1999-01-01

The first spectra of the A (2)Pi(sub 3/2) from X (2)Pi(sub 3/2) electronic transition of BrO using Fourier transform ultraviolet spectroscopy are obtained. Broadband vibrational spectra acquired at 298 +/- 2 K and 228 +/- 5 K, as well as high-resolution rotational spectra of the A from X 7,0 and 12,0 vibrational bands are presented. Wavenumber positions for the spectra are obtained with high accuracy, and cross section assignments are made, incorporating the existing literature. With 35 cm(exp -1) (0.40 nm) resolution the absolute cross section at the peak of the 7,0 band is determined to be (1.58 +/- 0.12) x 10(exp -17) sq cm/molecule at 298 +/- 2 K and (1.97 +/- 0.15) x 10(exp -17) sq cm/molecule at 228 +/- 5 K. BrO dissociation energies are determined with a graphical Birge-Sponer technique, using Le Roy-Bernstein theory to place an upper limit on the extrapolation. From the ground-state dissociation energy, D(sub o)" = 231.0 +/- 1.7 kJ/mol, the heat of formation of BrO(g) is calculated, del(sub f)H(0 K) = 133.7 +/- 1.7 kJ/mol and del(sub f)H(298.15 K) = 126.2 +/- 1.7 kJ/mol. Cross sections for the high-resolution 7,0 and 12,0 rotational peaks are the first to be reported. The band structures are modeled, and improved band origins, rotational constants, centrifugal distortion constants, and linewidths are determined. In particular, J-dependent linewidths and lifetimes are observed for the both the 7,0 and 12,0 bands.

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

Fares, Hssen; Férid, Mokhtar; Elhouichet, Habib, E-mail: habib.elhouichet@fst.rnu.tn

Tellurite glasses doped Er³⁺ ions and containing Silver nanoparticles (Ag NPs) are prepared using melt quenching technique. The nucleation and growth of Ag NPs were controlled by a thermal annealing process. The X-ray diffraction pattern shows no sharp peak indicating an amorphous nature of the glasses. The presence of Ag NPs is confirmed from transmission electron microscopy micrograph. Absorption spectra show typical surface plasmon resonance (SPR) band of Ag NPs within the 510–550 nm range in addition to the distinctive absorption peaks of Er³⁺ ions. The Judd-Ofelt (J-O) intensity parameters, oscillator strengths, spontaneous transition probabilities, branching ratios, and radiative lifetimesmore » were successfully calculated based on the experimental absorption spectrum and the J-O theory. It was found that the presence of silver NPs nucleated and grown during the heat annealing process improves both of the photoluminescence (PL) intensity and the PL lifetime relative to the ⁴I 13/2 → ⁴I 15/2 transition. Optimum PL enhancement was obtained after 10 h of heat-treatment. Such enhancements are mainly attributed to the strong local electric field induced by SPR of silver NPs and also to energy transfer from the surface of silver NPs to Er³⁺ ions, whereas the quenching is ascribed to the energy transfer from Er³⁺ ions to silver NPs. Using the Mc Cumber method, absorption cross-section, calculated emission cross-section, and gain cross-section for the ⁴I 13/2 → ⁴I 15/2 transition were determined and compared for the doped and co-doped glasses. The present results indicate that the glass heat-treated for 10 h has good prospect as a gain medium applied for 1.53 μm band broad and high-gain erbium-doped fiber amplifiers.« less

Soleus Fiber Force and Maximal Shortening Velocity After Non-Weight Bearing with Intermittent Activity

NASA Technical Reports Server (NTRS)

Widrick, Jeffrey J.; Bangart, Jill J.; Karhanek, Miloslav; Fitts, Robert H.

1996-01-01

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type 1 fiber force (in mN), tension (P(sub o); force per fiber cross-sectional area in kN/sq m), and maximal unloaded shortening velocity (V(sub o), in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca(2+) activation, after which type 1 fiber myosin heavy-chain composition was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type 1 fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in V(sub o) (+33%). In addition, NWB induced a 16% reduction in type 1 fiber P., a 41% reduction in type 1 fiber peak elastic modulus [E(sub o), defined as ((delta)force/(delta)length x (fiber length/fiber cross-sectional area] and a significant increase in the P(sub o)/E(sub o) ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type 1 fiber diameter (by 36%), peak force (by 29%), and V(sub o)(by 48%) but had no significant effect on P(sub o), E(sub o) or P(sub o)/E(sub o). These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type 1 fiber atrophy and to partially restore type 1 peak isometric force and V(sub o) to WB levels. However, the NWB-induced reductions in P(sub o) and E(sub o) which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

Spectral broadening of characteristic γ-ray emission peaks from 12C(3He,pγ)14N reactions in fusion plasmas.

PubMed

Tardocchi, M; Nocente, M; Proverbio, I; Kiptily, V G; Blanchard, P; Conroy, S; Fontanesi, M; Grosso, G; Kneupner, K; Lerche, E; Murari, A; Cippo, E Perelli; Pietropaolo, A; Syme, B; Van Eester, D; Gorini, G

2011-11-11

The spectral broadening of characteristic γ-ray emission peaks from the reaction (12)C((3)He,pγ)(14)N was measured in D((3)He) plasmas of the JET tokamak with ion cyclotron resonance heating tuned to the fundamental harmonic of (3)He. Intensities and detailed spectral shapes of γ-ray emission peaks were successfully reproduced using a physics model combining the kinetics of the reacting ions with a detailed description of the nuclear reaction differential cross sections for populating the L1-L8 (14)N excitation levels yielding the observed γ-ray emission. The results provide a paradigm, which leverages knowledge from areas of physics outside traditional plasma physics, for the development of nuclear radiation based methods for understanding and controlling fusion burning plasmas.

Spread of activation and deactivation in the brain: does age matter?

PubMed Central

Gordon, Brian A.; Tse, Chun-Yu; Gratton, Gabriele; Fabiani, Monica

2014-01-01

Cross-sectional aging functional MRI results are sometimes difficult to interpret, as standard measures of activation and deactivation may confound variations in signal amplitude and spread, which however, may be differentially affected by age-related changes in various anatomical and physiological factors. To disentangle these two types of measures, here we propose a novel method to obtain independent estimates of the peak amplitude and spread of the BOLD signal in areas activated (task-positive) and deactivated (task-negative) by a Sternberg task, in 14 younger and 28 older adults. The peak measures indicated that, compared to younger adults, older adults had increased activation of the task-positive network, but similar levels of deactivation in the task-negative network. Measures of signal spread revealed that older adults had an increased spread of activation in task-positive areas, but a starkly reduced spread of deactivation in task-negative areas. These effects were consistent across regions within each network. Further, there was greater variability in the anatomical localization of peak points in older adults, leading to reduced cross-subject overlap. These results reveal factors that may confound the interpretation of studies of aging. Additionally, spread measures may be linked to local connectivity phenomena and could be particularly useful to analyze age-related deactivation patterns, complementing the results obtained with standard peak and region of interest analyses. PMID:25360115

Triple differential cross-sections of Ne (2s2) in coplanar to perpendicular plane geometry

NASA Astrophysics Data System (ADS)

Chen, L. Q.; Khajuria, Y.; Chen, X. J.; Xu, K. Z.

2003-10-01

The distorted wave Born approximation (DWBA) with the spin averaged static exchange potential has been used to calculate the triple differential cross-sections (TDCSs) for Ne (2s^2) ionization by electron impact in coplanar to perpendicular plane symmetric geometry at 110.5 eV incident electron energy. The present theoretical results at gun angles Psi = 0^circ (coplanar symmetric geometry) and Psi = 90^circ (perpendicular plane geometry) are in satisfactory agreement with the available experimental data. A deep interference minimum appears in the TDCS in the coplanar symmetric geometry and a strong peak at scattering angle xi = 90^circ caused by the single collision mechanism has been observed in the perpendicular plane geometry. The TDCSs at the gun angles Psi = 30^circ, and Psi = 60^circ are predicted.

Photodisintegration cross section of the reaction 4He(γ,n)3He at the giant dipole resonance peak

NASA Astrophysics Data System (ADS)

Tornow, W.; Kelley, J. H.; Raut, R.; Rusev, G.; Tonchev, A. P.; Ahmed, M. W.; Crowell, A. S.; Stave, S. C.

2012-06-01

The photodisintegration cross section of 4He into a neutron and helion was measured at incident photon energies of 27.0, 27.5, and 28.0 MeV. A high-pressure 4He-Xe gas scintillator served as target and detector while a pure Xe gas scintillator was used for background measurements. A NaI detector in combination with the standard HIγS scintillator paddle system was employed for absolute photon-flux determination. Our data are in good agreement with the theoretical prediction of the Trento group and the recent data of Nilsson [Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.75.014007 75, 014007 (2007)] but deviate considerably from the high-precision data of Shima [Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.72.044004 72, 044004 (2005)].

The Variability of Childhood Diarrhea in Karachi, Pakistan, 2002–2006

PubMed Central

Luby, Stephen P.; Agboatwalla, Mubina; Hoekstra, Robert M.

2011-01-01

Diarrhea burden is often estimated using cross-sectional surveys. We measured variability in diarrhea prevalence among children < 5 years of age living in squatter settlements in central Karachi, Pakistan. We pooled data from non-intervention control households from studies conducted from 2002 through 2006. The prevalence of diarrhea varied on average by 29% from one week to the next, by 37% from one month to the next, and during peak diarrhea season by 32% from one year to the next. During 24 months when the same nine neighborhoods were under surveillance, each month the prevalence of diarrhea varied by at least an order of magnitude from the lowest to the highest prevalence neighborhood, and each neighborhood recorded the highest diarrhea prevalence during at least one month. Cross-sectional surveys are unreliable measures of diarrhea prevalence. PMID:21633021

Temperature dependent absorption cross-sections of O2-O2 collision pairs between 340 and 630 nm and at atmospherically relevant pressure.

PubMed

Thalman, Ryan; Volkamer, Rainer

2013-10-07

The collisions between two oxygen molecules give rise to O4 absorption in the Earth atmosphere. O4 absorption is relevant to atmospheric transmission and Earth's radiation budget. O4 is further used as a reference gas in Differential Optical Absorption Spectroscopy (DOAS) applications to infer properties of clouds and aerosols. The O4 absorption cross section spectrum of bands centered at 343, 360, 380, 446, 477, 532, 577 and 630 nm is investigated in dry air and oxygen as a function of temperature (203-295 K), and at 820 mbar pressure. We characterize the temperature dependent O4 line shape and provide high precision O4 absorption cross section reference spectra that are suitable for atmospheric O4 measurements. The peak absorption cross-section is found to increase at lower temperatures due to a corresponding narrowing of the spectral band width, while the integrated cross-section remains constant (within <3%, the uncertainty of our measurements). The enthalpy of formation is determined to be ΔH(250) = -0.12 ± 0.12 kJ mol(-1), which is essentially zero, and supports previous assignments of O4 as collision induced absorption (CIA). At 203 K, van der Waals complexes (O(2-dimer)) contribute less than 0.14% to the O4 absorption in air. We conclude that O(2-dimer) is not observable in the Earth atmosphere, and as a consequence the atmospheric O4 distribution is for all practical means and purposes independent of temperature, and can be predicted with an accuracy of better than 10(-3) from knowledge of the oxygen concentration profile.

Effects of mouthguards on vertical dimension, muscle activation, and athlete preference: a prospective cross-sectional study.

PubMed

Gage, C Colby; Huxel Bliven, Kellie C; Bay, R Curtis; Sturgill, Jeremiah S; Park, Jae Hyun

2015-01-01

Mandibular repositioning and subsequent neuromuscular signaling are proposed mechanisms of action for commercial mouthguards marketed for performance enhancement. A prospective cross-sectional study of 24 healthy adult weightlifters with normal occlusal relationships was designed to determine whether 2 self-fit performance mouthguards; a custom-fabricated, bilaterally balanced, dual-laminated mouthguard; and no mouthguard (control) differed in their effects on vertical dimension, muscle activation, and user preference during a 75% maximum power clean lift. Each subject was tested for each of the mouthguard categories: Power Balance POWERUP, Under Armour ArmourBite, custom, and no mouthguard. Interocclusal distance was measured at baseline and with each mouthguard. Mean and peak activity of the anterior temporalis, masseter, sternocleidomastoid, and cervical paraspinal muscles was measured during sitting and during a 75% maximum power clean lift. A mouthguard preference questionnaire was completed. Analyses were conducted to determine whether interocclusal distance differed among mouthguard type and to examine the effect of mouthguard type on mean and peak muscle activation during the clean lift. Interocclusal distance was affected by mouthguard type (P = 0.01). Mean and peak activity of the anterior temporalis and masseter muscles and mean activity of the sternocleidomastoid muscle differed among mouthguards (P < 0.05). Mouthguard type did not influence muscle activation of the cervical paraspinal muscle group. Overall, the Power Balance mouthguard produced more muscle activity. Participants preferred custom mouthguards nearly 2:1 over self-fit performance mouthguards (P = 0.05). Participants perceived that they were stronger and were less encumbered when using a custom mouthguard during submaximum power clean lifts.

Change in mobility function and its causes in adults with cerebral palsy by Gross Motor Function Classification System level: A cross-sectional questionnaire study.

PubMed

Himuro, Nobuaki; Mishima, Reiko; Seshimo, Takashi; Morishima, Toshibumi; Kosaki, Keisuke; Ibe, Shigeharu; Asagai, Yoshimi; Minematsu, Koji; Kurita, Kazuhiro; Okayasu, Tsutomu; Shimura, Tsukasa; Hoshino, Kotaro; Suzuki, Toshiro; Yanagizono, Taiichiro

2018-04-07

The prognosis for mobility function by Gross Motor Function Classification System (GMFCS) level is vital as a guide to rehabilitation for people with cerebral palsy. This study sought to investigate change in mobility function and its causes in adults with cerebral palsy by GMFCS level. We conducted a cross-sectional questionnaire study. A total of 386 participants (26 y 8 m, SD 5 y 10 m) with cerebral palsy were analyzed. Participant numbers by GMFCS level were: I (53), II (139), III (74) and IV (120). The median age of participants with peak mobility function in GMFCS level III was younger than that in the other levels. 48% had experienced a decline in mobility. A Kaplan-Meier plot showed the risk of mobility decline increased in GMFCS level III; the hazard ratio was 1.97 (95% CI, 1.20-3.23) compared with level I. The frequently reported causes of mobility decline were changes in environment, and illness and injury in GMFCS level III, stiffness and deformity in level IV, and reduced physical activity in level II and III. Peak mobility function and mobility decline occurred at a younger age in GMFCS level III, with the cause of mobility decline differing by GMFCS level.

Effects of Renal Denervation on Renal Artery Function in Humans: Preliminary Study

PubMed Central

Doltra, Adelina; Hartmann, Arthur; Stawowy, Philipp; Goubergrits, Leonid; Kuehne, Titus; Wellnhofer, Ernst; Gebker, Rolf; Schneeweis, Christopher; Schnackenburg, Bernhard; Esler, Murray; Fleck, Eckart; Kelle, Sebastian

2016-01-01

Aim To study the effects of RD on renal artery wall function non-invasively using magnetic resonance. Methods and Results 32 patients undergoing RD were included. A 3.0 Tesla magnetic resonance of the renal arteries was performed before RD and after 6-month. We quantified the vessel sharpness of both renal arteries using a quantitative analysis tool (Soap-Bubble®). In 17 patients we assessed the maximal and minimal cross-sectional area of both arteries, peak velocity, mean flow, and renal artery distensibility. In a subset of patients wall shear stress was assessed with computational flow dynamics. Neither renal artery sharpness nor renal artery distensibility differed significantly. A significant increase in minimal and maximal areas (by 25.3%, p = 0.008, and 24.6%, p = 0.007, respectively), peak velocity (by 16.9%, p = 0.021), and mean flow (by 22.4%, p = 0.007) was observed after RD. Wall shear stress significantly decreased (by 25%, p = 0.029). These effects were observed in blood pressure responders and non-responders. Conclusions RD is not associated with adverse effects at renal artery level, and leads to an increase in cross-sectional areas, velocity and flow and a decrease in wall shear stress. PMID:27003912

Dose response effect of cement dust on respiratory muscles competence in cement mill workers.

PubMed

Meo, Sultan A; Azeem, Muhammad A; Qureshi, Aijaz A; Ghori, G Moinudin; Al-Drees, Abdul Majeed; Feisal Subhan, Mirza Muhammad

2006-12-01

Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sectional study of EMG in 50 non-smoking cement mill workers with an age range of 20 - 60 years, who worked without the benefit of cement dust control ventilation or respiratory protective devices. EMG was performed by using surface electrodes and chart recorder. Significant reduction was observed in number of peaks (p < 0.0005), maximum peak amplitude (p < 0.0005), peak-to-peak amplitude (p < 0.0005) and duration of response (p < 0.0005) in cement mill workers compared to their matched control. Cement dust impairs the intercostal muscle competence and stratification of results shows a dose-effect of years of exposure in cement mill.

The Fission of Thorium with Alpha Particles

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

Newton, Amos S.

1948-04-15

The fission distribution of fission of thorium with alpha particle of average energy 37.5 Mev has been measured by the chemical method. The distribution found shows that the characteristic dip in the fission yield mass spectrum has been raised to within a factor of two of the peaks compared to a factor of 600 in slow neutron fission of U{sup 235}. The raise in the deip has caused a corresponding lowering in fission yield of these elements at the peaks. The cross section for fission of thorium with 37.5 Mev alphas was found to be about 0.6 barn, and themore » threshold for fission was found to be 23 to 24 Mev.« less

Hard matching for boosted tops at two loops

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

Hoang, Andre H.; Pathak, Aditya; Pietrulewicz, Piotr

2015-12-10

Here, cross sections for top quarks provide very interesting physics opportunities, being both sensitive to new physics and also perturbatively tractable due to the large top quark mass. Rigorous factorization theorems for top cross sections can be derived in several kinematic scenarios, including the boosted regime in the peak region that we consider here. In the context of the corresponding factorization theorem for e +e – collisions we extract the last missing ingredient that is needed to evaluate the cross section differential in the jet-mass at two-loop order, namely the matching coefficient at the scale μ≃m t. Our extraction alsomore » yields the final ingredients needed to carry out logarithmic re-summation at next-to-next-to-leading logarithmic order (or N 3LL if we ignore the missing 4-loop cusp anomalous dimension). This coefficient exhibits an amplitude level rapidity logarithm starting at O(α 2 s) due to virtual top quark loops, which we treat using rapidity renormalization group (RG) evolution. Interestingly, this rapidity RG evolution appears in the matching coefficient between two effective theories around the heavy quark mass scale μ ≃ m t.« less

Long-period grating fabricated by periodically tapering standard single-mode fiber.

PubMed

Shao, Li-Yang; Zhao, Jian; Dong, Xinyong; Tam, H Y; Lu, C; He, Sailing

2008-04-01

We fabricated an asymmetric long-period grating (LPG) by periodically tapering a section of standard single-mode fiber using a resistive filament heating. The LPG exhibits large peak transmission attenuation of -30.31 dB with only 22 periods in a 1.0 cm long optical fiber and possesses unique characteristics for sensing applications. The bending and strain sensitivities are 1.74 nm m and 1.11 pm/mu epsilon, respectively. The polarization dependent loss is large, up to 11.65 dB, which is caused by an asymmetric index profile in the cross section of the tapered LPG.

On the tidal prism-channel area relations

NASA Astrophysics Data System (ADS)

D'Alpaos, Andrea; Lanzoni, Stefano; Marani, Marco; Rinaldo, Andrea

2010-03-01

We verify the broad applicability of tidal prism cross-sectional area relationships, originally proposed to relate the total water volume entering a lagoon during a characteristic tidal cycle (the tidal prism) to the size of its inlet, to arbitrary sheltered cross sections within a tidal network. We suggest, with reasonable approximation defining a statistical tendency rather than a pointwise equivalence, that the regime of tidal channels may be anywhere related to local landscape-forming prisms embedded in a characteristic spring tide oscillation. The importance of the proposed extension stems from its potential for quantitative predictions of the long-term morphological evolution of whole tidal landforms, in response to forcings affecting tidal prisms. This is the case, in particular, for alterations of relative mean sea levels possibly driven by climate change. Various 1-D and 2-D morphodynamic and hydrodynamic models are employed to evaluate peak flow rates, bottom shear stresses, and the ensuing local tidal prisms. One-dimensional morphodynamic models describing both the longitudinal and cross-sectional evolution of tidal channels are used to verify the validity of the relationship for sheltered sections. Relevant hydrodynamic features determined through accurate 2-D numerical models are compared with those obtained through time-invariant equivalents, defining a mean watershed by an energy landscape from averaged free surface gradients. Empirical evidence gathered within the lagoon of Venice (Italy) supports the proposed extension. We conclude that the geomorphic law relating tidal prisms to channel cross-sectional areas anywhere within a tidal landscape is a valuable tool for studies on long-term tidal geomorphology.

Measurement of numu induced charged current inclusive cross section on water using the near detector of the T2K experiment

NASA Astrophysics Data System (ADS)

Das, Rajarshi

The Tokai to Kamioka (T2K) Experiment is a long-baseline neutrino oscillation experiment located in Japan with the primary goal to measure precisely multiple neutrino flavor oscillation parameters. An off-axis muon neutrino beam peaking at 600 MeV is generated at the JPARC facility and directed towards the 50 kiloton Super-Kamiokande (SK) water Cherenkov detector located 295 km away. Measurements from a Near Detector that is 280m downstream of the neutrino beam target are used to constrain uncertainties in the beam flux prediction and neutrino interaction rates. We present a selection of inclusive charged current neutrino interactions on water. We used several sub-detectors in the ND280 complex, including a Pi-Zero detector (P0D) that has alternating planes of plastic scintillator and water bag layers, a time projection chamber (TPC) and fine-grained detector (FGD) to detect and reconstruct muons from neutrino charged current events. We use a statistical subtraction method with the water-in and water-out inclusive selection to extract a flux-averaged, ν_μ induced, charged current inclusive cross section. We also outline the evaluation of systematic uncertainties. We find an absolute cross section of ⟨σ⟩=(6.37 ± 0.157(stat.) (-1.060/+0.910(sys.)) x 10-39 (cm. 2/H2O nucleon). This is the first ν_μ charged current inclusive cross section measurement on water.

Planar small-angle x-ray scattering imaging of phantoms and biological samples

NASA Astrophysics Data System (ADS)

Choi, M.; Badano, A.

2017-04-01

Coherent small-angle x-ray scattering (SAXS) provides molecular and nanometer-scale structural information. By capturing SAXS data at multiple locations across a sample, we obtained planar images and observed improved contrast given by the difference in the material scattering cross sections. We use phantoms made with 3D printing techniques, with tissue-mimicking plastic (PMMA), and with a highly scattering reference material (AgBe), which were chosen because of their well characterized scattering cross section to demonstrate and characterize the planar imaging of a laboratory SAXS system. We measure 1.07 and 2.14 nm-1 angular intensity maps for AgBe, 9.5 nm-1 for PMMA, and 12.3 nm-1 for Veroclear. The planar SAXS images show material discrimination based on their cross sectional features. The image signal-to-noise ratio (SNR) of each q image was dependent on exposure time and x-ray flux. We observed a lower SNR (91 ± 48) at q angles where no characteristic peaks for either material exist. To improve the visualization of the acquired data by utilizing all q-binned data, we describe a weighted-sum presentation method with a priori knowledge of relevant cross sections to improve the SNR (10 000 ± 6400) over the SNR from a single q-image at 1.07 nm-1 (1100 ± 620). In addition, we describe planar SAXS imaging of a mouse brain slice showing differentiation of tissue types as compared to a conventional absorption-based x-ray imaging technique.

Photoproduction of Λ and Σ0 hyperons off protons with linearly polarized photons at Eγ=1.5 -3.0 GeV

NASA Astrophysics Data System (ADS)

Shiu, S. H.; Kohri, H.; Chang, W. C.; Ahn, D. S.; Ahn, J. K.; Chen, J. Y.; Daté, S.; Ejiri, H.; Fujimura, H.; Fujiwara, M.; Fukui, S.; Gohn, W.; Hicks, K.; Hotta, T.; Hwang, S. H.; Imai, K.; Ishikawa, T.; Joo, K.; Kato, Y.; Kon, Y.; Lee, H. S.; Maeda, Y.; Mibe, T.; Miyabe, M.; Mizutani, K.; Morino, Y.; Muramatsu, N.; Nakano, T.; Nakatsugawa, Y.; Niiyama, M.; Noumi, H.; Ohashi, Y.; Ohta, T.; Oka, M.; Parker, J. D.; Rangacharyulu, C.; Ryu, S. Y.; Sawada, T.; Shimizu, H.; Sugaya, Y.; Sumihama, M.; Tsunemi, T.; Uchida, M.; Ungaro, M.; Yosoi, M.; LEPS Collaboration

2018-01-01

We report the measurement of the γ p →K+Λ and γ p →K+Σ0 reactions at SPring-8. The differential cross sections and photon-beam asymmetries are measured at forward K+ production angles using linearly polarized tagged-photon beams in the range of Eγ=1.5 -3.0 GeV. With increasing photon energy, the cross sections for both γ p →K+Λ and γ p →K+Σ0 reactions decrease slowly. Distinct narrow structures in the production cross section have not been found at Eγ=1.5 -3.0 GeV. The forward peaking in the angular distributions of cross sections, a characteristic feature of t -channel exchange, is observed for the production of Λ in the whole observed energy range. A lack of similar feature for Σ0 production reflects a less dominant role of t -channel contribution in this channel. The photon-beam asymmetries remain positive for both reactions, suggesting the dominance of K* exchange in the t channel. These asymmetries increase gradually with the photon energy, and have a maximum value of +0.6 for both reactions. Comparison with theoretical predictions based on the Regge trajectory in the t channel and the contributions of nucleon resonances indicates the major role of t -channel contributions as well as non-negligible effects of nucleon resonances in accounting for the reaction mechanism of hyperon photoproduction in this photon energy regime.

Predicting K0Λ photoproduction observables by using the multipole approach

NASA Astrophysics Data System (ADS)

Mart, T.; Rusli, A.

2017-12-01

We present an isobar model for kaon photoproduction on the proton γ p\\to K^+Λ that can nicely reproduce the available experimental data from threshold up to W=2.0 GeV. The background amplitude of the model is constructed from a covariant Feynman diagrammatic method, whereas the resonance one is formulated by using the multipole approach. All unknown parameters in both background and resonance amplitudes are extracted by adjusting the calculated observables to experimental data. With the help of SU(3) isospin symmetry and some information obtained from the Particle Data Group we estimate the cross section and polarization observables for the neutral kaon photoproduction on the neutron γ n\\to K^0Λ. The result indicates no sharp peak in the K^0Λ total cross section. The predicted differential cross section exhibits resonance structures only at cosθ=-1. To obtain sizable observables the present work recommends measurement of the K^0Λ cross section with W≳ 1.70 GeV, whereas for the recoiled Λ polarization measurement with W≈ 1.65-1.90 GeV would be advised, since the predictions of existing models show a large variance at this kinematics. The predicted electric and magnetic multipoles are found to be mostly different from those obtained in previous works. For W=1.75 and 1.95 GeV it is found that most of the single and double polarization observables demonstrate large asymmetries.

Soliton Microwave Generator

NASA Astrophysics Data System (ADS)

Degrassie, J. S.

1990-12-01

The Soliton Microwave Generator (SMG) represents a truly new concept in the field of high power microwave (HPM) generation. A nonlinear, dispersive transmission line is used to convert an input voltage pulse into an HPM burst at the output. The system is all solid state and projects to be efficient and reliable. Single module peak powers in excess of 1 GW appear feasible, while combining modular units leads to a 10 GW system projection. This project for the DOE has allowed the first steps necessary in experimentally demonstrating the SMG. The project has ended successfully. A relatively high power lumped circuit SMG operating in the uhf band was designed, fabricated, and tested. The maximum peak output RF power was 16 MW from this line approx. 90 cm in length and 2 sq cm in cross section with a peak power efficiency of roughly 20 percent. Additionally a low power continuous strip-line approach demonstrated microwave generation well into L band, at approx. 2 GHz.

Cosmic signatures in earth's seismic tremor?

NASA Astrophysics Data System (ADS)

Mulargia, Francesco

2017-01-01

Even in absence of earthquakes, each site on earth experiences continuous elastic vibrations which are mostly traced to the nonlinear interactions of ocean waves. However, the fine structure of the spectrum at mHz frequencies shows many persistent and highly significant narrow bandwidth peaks in surprising coincidence with solar acoustic eigenmodes. The feasibility of a common cosmic origin is evaluated through an estimate of the gravitational wave cross-section of the earth, combined with its elastic response and with the stochastic amplification produced by the interference of the cosmic signal with tremor of oceanic origin. The measured spectral peaks appear compatible with a gravitational monochromatic illumination at strains h ≳ 10-20, larger than those expected for any known gravitational stellar source. Hence, a gravitational source attribution to the tremor spectral peaks would call for a population of unknown non-luminous sources with well-defined mass-distance ratios.

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF{sub 3}: A comparative study with XF{sub 3} (X = C, N, and CH) molecules

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

Hoshino, M., E-mail: masami-h@sophia.ac.jp; Suga, A.; Kato, H.

2015-07-14

Absolute differential cross sections (DCSs) for electron interaction with BF{sub 3} molecules have been measured in the impact energy range of 1.5–200 eV and recorded over a scattering angle range of 15°–150°. These angular distributions have been normalized by reference to the elastic DCSs of the He atom and integrated by employing a modified phase shift analysis procedure to generate integral cross sections (ICSs) and momentum transfer cross sections (MTCSs). The calculations of DCSs and ICSs have been carried out using an independent atom model under the screening corrected additivity rule (IAM-SCAR). The present elastic DCSs have been found tomore » agree well with the results of IAM-SCAR calculation above 20 eV, and also with a recent Schwinger multichannel calculation below 30 eV. Furthermore, in the comparison with the XF{sub 3} (X = B, C, N, and CH) molecules, the elastic DCSs reveal a similar angular distribution which are approximately equal in magnitude from 30 to 200 eV. This feature suggests that the elastic scattering is dominated virtually by the 3-outer fluorine atoms surrounding the XF{sub 3} molecules. The vibrational DCSs have also been obtained in the energy range of 1.5–15 eV and vibrational analysis based on the angular correlation theory has been carried out to explain the nature of the shape resonances. Limited experiments on vibrational inelastic scattering confirmed the existence of a shape resonance with a peak at 3.8 eV, which is also observed in the vibrational ICS. Finally, the estimated elastic ICSs, MTCSs, as well as total cross sections are compared with the previous cross section data available.« less

Origin of visible and near-infrared photoluminescence from chemically etched Si nanowires decorated with arbitrarily shaped Si nanocrystals.

PubMed

Ghosh, Ramesh; Giri, P K; Imakita, Kenji; Fujii, Minoru

2014-01-31

Arrays of vertically aligned single crystalline Si nanowires (NWs) decorated with arbitrarily shaped Si nanocrystals (NCs) have been fabricated by a silver assisted wet chemical etching method. Scanning electron microscopy and transmission electron microscopy are performed to measure the dimensions of the Si NWs as well as the Si NCs. A strong broad band and tunable visible (2.2 eV) to near-infrared (1.5 eV) photoluminescence (PL) is observed from these Si NWs at room temperature (RT). Our studies reveal that the Si NCs are primarily responsible for the 1.5-2.2 eV emission depending on the cross-sectional area of the Si NCs, while the large diameter Si/SiOx NWs yield distinct NIR PL consisting of peaks at 1.07, 1.10 and 1.12 eV. The latter NIR peaks are attributed to TO/LO phonon assisted radiative recombination of free carriers condensed in the electron-hole plasma in etched Si NWs observed at RT for the first time. Since the shape of the Si NCs is arbitrary, an analytical model is proposed to correlate the measured PL peak position with the cross-sectional area (A) of the Si NCs, and the bandgap (E(g)) of nanostructured Si varies as E(g) = E(g) (bulk) + 3.58 A(-0.52). Low temperature PL studies reveal the contribution of non-radiative defects in the evolution of PL spectra at different temperatures. The enhancement of PL intensity and red-shift of the PL peak at low temperatures are explained based on the interplay of radiative and non-radiative recombinations at the Si NCs and Si/SiO(x) interface. Time resolved PL studies reveal bi-exponential decay with size correlated lifetimes in the range of a few microseconds. Our results help to resolve a long standing debate on the origin of visible-NIR PL from Si NWs and allow quantitative analysis of PL from arbitrarily shaped Si NCs.

Resonant inelastic collisions of electrons with diatomic molecules

NASA Astrophysics Data System (ADS)

Houfek, Karel

2012-05-01

In this contribution we give a review of applications of the nonlocal resonance theory which has been successfully used for treating the nuclear dynamics of low-energy electron collisions with diatomic molecules over several decades. We give examples and brief explanations of various structures observed in the cross sections of vibrational excitation and dissociative electron attachment to diatomic molecules such as threshold peaks, boomerang oscillations below the dissociative attachment threshold, or outer-well resonances.

Gamow-Teller strength observed in the 48Ti(n, p) 48Sc reaction: Implications for the double beta decay of 48Ca

NASA Astrophysics Data System (ADS)

Alford, W. P.; Helmer, R. L.; Abegg, R.; Celler, A.; Frekers, D.; Green, P.; Häusser, O.; Henderson, R.; Hicks, K.; Jackson, K. P.; Jeppesen, R.; Miller, C. A.; Trudel, A.; Vetterli, M.; Yen, S.; Pourang, R.; Watson, J.; Brown, B. A.; Engel, J.

1990-07-01

Cross sections for the 48Ti(n, p) reaction have been measured at angles of 0°, 6°, and 12° at an energy of 200 MeV. The measurements are compared with results of DWIA calculations to obtain estimates of transition strengths for L = 0, 1, and ⩾2 up to an excitation energy of 25 MeV. Gamow-Teller strength ( L = 0) is peaked between 3 and 4 MeV excitation energy, with a significant distribution extending to about 12 MeV. The L = 1 strength is found mainly between 6 and 20 MeV while the cross section for transitions with L ⩾2 increases from 10 MeV to the upper limit of the measurements. The distribution of Gamow-Teller strength is in poor agreement with theoretical distributions used to calculate the lifetime for double beta decay of 48Ca.

Elucidating the charge carrier separation and working mechanism of CH3NH3PbI(3-x)Cl(x) perovskite solar cells.

PubMed

Edri, Eran; Kirmayer, Saar; Mukhopadhyay, Sabyasachi; Gartsman, Konstantin; Hodes, Gary; Cahen, David

2014-03-11

Developments in organic-inorganic lead halide-based perovskite solar cells have been meteoric over the last 2 years, with small-area efficiencies surpassing 15%. We address the fundamental issue of how these cells work by applying a scanning electron microscopy-based technique to cell cross-sections. By mapping the variation in efficiency of charge separation and collection in the cross-sections, we show the presence of two prime high efficiency locations, one at/near the absorber/hole-blocking-layer, and the second at/near the absorber/electron-blocking-layer interfaces, with the former more pronounced. This 'twin-peaks' profile is characteristic of a p-i-n solar cell, with a layer of low-doped, high electronic quality semiconductor, between a p- and an n-layer. If the electron blocker is replaced by a gold contact, only a heterojunction at the absorber/hole-blocking interface remains.

Differential cross section of γ n → K + Σ - on bound neutrons with incident photons from 1.1 to 3.6 GeV

DOE PAGES

Pereira, S. Anefalos; Mirazita, M.; Rossi, P.; ...

2010-05-01

Differential cross sections of the reaction γd → K +Σ –(p) have been measured with the CLAS detector at Jefferson Lab using incident photons with energies between 1.1 and 3.6 GeV. This is the first complete set of strangeness photoproduction data on the neutron covering a broad angular range. At energies close to threshold and up to E γ ~ 1.8 GeV, the shape of the angular distribution is suggestive of the presence of s -channel production mechanisms. For E γ > 1.8 GeV, a clear forward peak appears and becomes more prominent as the photon energy increases, suggesting contributionsmore » from t-channel production mechanisms. Furthermore, these data can be used to constrain future analysis of this reaction.« less

Angular distribution of binary encounter electrons

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

Liao, C.; Richard, P.; Grabbe, S.

The double differential cross section, DDCS, of the binary encounter electrons (BEe) in 1 MeV/u F{sup q+} + H{sub 2} (q = 4, 6, 8, 9) is measured from 0 to 70 degrees with respect to the beam direction. At 0{degrees} the data confirm the decrease of the cross section with increasing projectile charge state. At larger observation angles, the data are in fair agreement with the prediction proposed by Shingal et al. where the ratio of the DDCS for 6+ ions to bare ions is less than 1 for {theta}{sub lab} > 30{degrees} and greater than 1 for {theta}{submore » lab} < 30{degrees} as recently observed for C{sup q+}. We also observed that the energies of the BEe peak are charge state, q, independent at 0{degrees} observation angle, but q dependent at larger observation angles.« less

Many-Body Effects in the Mesoscopic x-Ray Edge Problem

NASA Astrophysics Data System (ADS)

Hentschel, M.; R"Oder, G.; Ullmo, D.

Many-body phenomena, a key interest in the investigation ofbulk solid state systems, are studied here in the context of the x-ray edge problem for mesoscopic systems. We investigate the many-body effects associated with the sudden perturbation following the x-ray excition of a core electron into the conduction band. For small systems with dimensions at the nanoscale we find considerable deviations from the well-understood metallic case where Anderson orthogonality catastrophe and the Mahan-Nozières-DeDominicis response cause characteristic deviations of the photoabsorption cross section from the naive expectation. Whereas the K-edge is typically rounded in metallic systems, we find a slightly peaked K-edge in generic mesoscopic systems with chaotic-coherent electron dynamics. Thus the behavior of the photoabsorption cross section at threshold depends on the system size and is different for the metallic and the mesoscopic case.

Two-step excitation and blue fluorescence under continuous-wave pumping in Nd:YLF

NASA Technical Reports Server (NTRS)

Fan, T. Y.; Byer, Robert L.

1986-01-01

Near-UV and blue fluorescence from the 4D3/2 and 4D5/2 manifolds in Nd:YLF has been observed at room temperature under CW pumping by a rhodamine 590 dye laser. Excitation to these manifolds is attributed to two-step excitation involving excited-state absorption from the 4F3/2 metastable level. A similar phenomenon has also been observed in Nd:YAG and Nd:glass. The effective excited-state absorption cross section is measured to be (2 + or - 1) x 10 to the -20th sq cm at 587.4 nm in the pi polarization, and the peak effective stimulated emission cross section is measured to be 5 x 10 to the -20th sq cm at 411.7 nm, also in the pi polarization. Estimated laser threshold at 411.7 nm for two-step pumping at 587.4 nm is 70 mW.

Ultraviolet absorption spectrum of HOCl

NASA Technical Reports Server (NTRS)

Burkholder, James B.

1993-01-01

The room temperature UV absorption spectrum of HOCl was measured over the wavelength range 200 to 380 nm with a diode array spectrometer. The absorption spectrum was identified from UV absorption spectra recorded following UV photolysis of equilibrium mixtures of Cl2O/H2O/HOCl. The HOCl spectrum is continuous with a maximum at 242 nm and a secondary peak at 304 nm. The measured absorption cross section at 242 nm was (2.1 +/- 0.3) x 10 exp -19/sq cm (2 sigma error limits). These results are in excellent agreement with the work of Knauth et al. (1979) but in poor agreement with the more recent measurements of Mishalanie et al. (1986) and Permien et al. (1988). An HOCl nu2 infrared band intensity of 230 +/- 35/sq cm atm was determined based on this UV absorption cross section. The present results are compared with these previous measurements and the discrepancies are discussed.

Spectral properties of Er3+/Yb3+ codoped tungsten-tellurite glasses.

PubMed

Shen, Xiang; Nie, QiuHua; Xu, TieFeng; Gao, Yuan

2005-07-01

The spectral properties of Er3+/Yb3+ codoped tungsten-tellurite (WT) glasses have been investigated. The measured absorption spectra are analyzed by Judd-Ofelt theory. The compositional change of intensity parameter omega2 is attributed to the change in the covalency between the Er3+ and oxygen ions, the asymmetry in the local structures around the Er3+ ions can be neglected. The lifetimes of 4I(13/2) level of Er3+ in WT glasses are measured and comparable with other TeO2-based glasses. The stimulated emission cross-section is calculated based on McCumber theory. The fluorescence full width at half maximum (FWHM) and the emission cross-section (sigma(peak)) of the 4I(13/2) --> 4I(15/2) transition of Er3+ in different glass hosts have been compared. The suitability of such WT glasses as host materials for 1.5 microm broadband amplification is discussed.

Optical transitions of Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 glass.

PubMed

Shen, Xiang; Nie, Qiuhua; Xu, Tiefeng; Gao, Yuan

2005-10-01

Optical absorption and emission properties of the Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 (TWB) glass has been investigated. The transition probabilities, excited state lifetimes, and the branching ratios have been predicted for Er3+ based on the Judd-Ofelt theory. The broad 1.5 microm fluorescence was observed under 970 nm excitation, and its full width at half maximum (FWHM) is 77 nm. The emission cross-section is calculated using the McCumber theory, and the peak emission cross-section is 1.03 x 10(-21) cm2 at 1.531 microm. This value is much larger than those of the silicate and phosphate glasses. Efficient green and weak red upconversion luminescence from Er3+ centers in the glass sample was observed at room temperature, and the upconversion excitation processes have been analyzed.

Optical spectroscopy of low-phonon Ho3+ doped BaY2F8 single crystal

NASA Astrophysics Data System (ADS)

Li, Chun; Zeng, Fanming; Lin, Hai; Zheng, Dongyang; Yang, Xiaodong; Liu, Wang; Liu, Jinghe

2014-12-01

The Ho:BaY2F8 crystal was grown by Czochralski method. The crystal phase structure and absorption spectra were tested, the absorption peak exists near 899 nm, the absorption cross section was 1.27 × 10-21 cm2. The emission spectra of crystals in the vicinity of 2 and 3.9 μm were measured, the 2 μm near infrared light induced by 5I7 → 5I8 transition of Ho3+ ions was observed, as well as the fluorescence output at 3.9 μm (5I5 → 5I6), emission cross section at 3.9 μm was calculated to be 0.86 × 10-21 cm2. We suppose that the Ho:BaY2F8 crystal has a large application prospect for the 2-4 μm wavelength near infrared laser.

Acoustical scattering by multilayer spherical elastic scatterer containing electrorheological layer.

PubMed

Cai, Liang-Wu; Dacol, Dacio K; Orris, Gregory J; Calvo, David C; Nicholas, Michael

2011-01-01

A computational procedure for analyzing acoustical scattering by multilayer concentric spherical scatterers having an arbitrary mixture of acoustic and elastic materials is proposed. The procedure is then used to analyze the scattering by a spherical scatterer consisting of a solid shell and a solid core encasing an electrorheological (ER) fluid layer, and the tunability in the scattering characteristics afforded by the ER layer is explored numerically. Tunable scatterers with two different ER fluids are analyzed. One, corn starch in peanut oil, shows that a significant increase in scattering cross-section is possible in moderate frequencies. Another, fine poly-methyl methacrylate (PMMA) beads in dodecane, shows only slight change in scattering cross-sections overall. But, when the shell is thin, a noticeable local resonance peak can appear near ka=1, and this resonance can be turned on or off by the external electric field.

Automated Processing of Two-Dimensional Correlation Spectra

PubMed

Sengstschmid; Sterk; Freeman

1998-04-01

An automated scheme is described which locates the centers of cross peaks in two-dimensional correlation spectra, even under conditions of severe overlap. Double-quantum-filtered correlation (DQ-COSY) spectra have been investigated, but the method is also applicable to TOCSY and NOESY spectra. The search criterion is the intrinsic symmetry (or antisymmetry) of cross-peak multiplets. An initial global search provides the preliminary information to build up a two-dimensional "chemical shift grid." All genuine cross peaks must be centered at intersections of this grid, a fact that reduces the extent of the subsequent search program enormously. The program recognizes cross peaks by examining the symmetry of signals in a test zone centered at a grid intersection. This "symmetry filter" employs a "lowest value algorithm" to discriminate against overlapping responses from adjacent multiplets. A progressive multiplet subtraction scheme provides further suppression of overlap effects. The processed two-dimensional correlation spectrum represents cross peaks as points at the chemical shift coordinates, with some indication of their relative intensities. Alternatively, the information is presented in the form of a correlation table. The authenticity of a given cross peak is judged by a set of "confidence criteria" expressed as numerical parameters. Experimental results are presented for the 400-MHz double-quantum-filtered COSY spectrum of 4-androsten-3,17-dione, a case where there is severe overlap. Copyright 1998 Academic Press.

Impact of chevron spacing and asymmetric distribution on supersonic jet acoustics and flow

NASA Astrophysics Data System (ADS)

Heeb, N.; Gutmark, E.; Kailasanath, K.

2016-05-01

An experimental investigation into the effect of chevron spacing and distribution on supersonic jets was performed. Cross-stream and streamwise particle imaging velocimetry measurements were used to relate flow field modification to sound field changes measured by far-field microphones in the overexpanded, ideally expanded, and underexpanded regimes. Drastic modification of the jet cross-section was achieved by the investigated configurations, with both elliptic and triangular shapes attained downstream. Consequently, screech was nearly eliminated with reductions in the range of 10-25 dB depending on the operating condition. Analysis of the streamwise velocity indicated that both the mean shock spacing and strength were reduced resulting in an increase in the broadband shock associated noise spectral peak frequency and a reduction in the amplitude, respectively. Maximum broadband shock associated noise amplitude reductions were in the 5-7 dB range. Chevron proximity was found to be the primary driver of peak vorticity production, though persistence followed the opposite trend. The integrated streamwise vorticity modulus was found to be correlated with peak large scale turbulent mixing noise reduction, though optimal overall sound pressure level reductions did not necessarily follow due to the shock/fine scale mixing noise sources. Optimal large scale mixing noise reductions were in the 5-6 dB range.

Accurate prediction of cardiorespiratory fitness using cycle ergometry in minimally disabled persons with relapsing-remitting multiple sclerosis.

PubMed

Motl, Robert W; Fernhall, Bo

2012-03-01

To examine the accuracy of predicting peak oxygen consumption (VO(2peak)) primarily from peak work rate (WR(peak)) recorded during a maximal, incremental exercise test on a cycle ergometer among persons with relapsing-remitting multiple sclerosis (RRMS) who had minimal disability. Cross-sectional study. Clinical research laboratory. Women with RRMS (n=32) and sex-, age-, height-, and weight-matched healthy controls (n=16) completed an incremental exercise test on a cycle ergometer to volitional termination. Not applicable. Measured and predicted VO(2peak) and WR(peak). There were strong, statistically significant associations between measured and predicted VO(2peak) in the overall sample (R(2)=.89, standard error of the estimate=127.4 mL/min) and subsamples with (R(2)=.89, standard error of the estimate=131.3 mL/min) and without (R(2)=.85, standard error of the estimate=126.8 mL/min) multiple sclerosis (MS) based on the linear regression analyses. Based on the 95% confidence limits for worst-case errors, the equation predicted VO(2peak) within 10% of its true value in 95 of every 100 subjects with MS. Peak VO(2) can be accurately predicted in persons with RRMS who have minimal disability as it is in controls by using established equations and WR(peak) recorded from a maximal, incremental exercise test on a cycle ergometer. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

The Andersen aerobic fitness test: New peak oxygen consumption prediction equations in 10 and 16-year olds.

PubMed

Aadland, E; Andersen, L B; Lerum, Ø; Resaland, G K

2018-03-01

Measurement of aerobic fitness by determining peak oxygen consumption (VO 2peak ) is often not feasible in children and adolescents, thus field tests such as the Andersen test are required in many settings, for example in most school-based studies. This study provides cross-validated prediction equations for VO 2peak based on the Andersen test in 10 and 16-year-old children. We included 235 children (n = 113 10-year olds and 122 16-year olds) who performed the Andersen test and a progressive treadmill test to exhaustion to determine VO 2peak . Joint and sex-specific prediction equations were derived and tested in 20 random samples. Performance in terms of systematic (bias) and random error (limits of agreement) was evaluated by means of Bland-Altman plots. Bias varied from -4.28 to 5.25 mL/kg/min across testing datasets, sex, and the 2 age groups. Sex-specific equations (mean bias -0.42 to 0.16 mL/kg/min) performed somewhat better than joint equations (-1.07 to 0.84 mL/kg/min). Limits of agreement were substantial across all datasets, sex, and both age groups, but were slightly lower in 16-year olds (5.84-13.29 mL/kg/min) compared to 10-year olds (9.60-15.15 mL/kg/min). We suggest the presented equations can be used to predict VO 2peak from the Andersen test performance in children and adolescents on a group level. Although the Andersen test appears to be a good measure of aerobic fitness, researchers should interpret cross-sectional individual-level predictions of VO 2peak with caution due to large random measurement errors. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Quantifying peak discharges for historical floods

USGS Publications Warehouse

Cook, J.L.

1987-01-01

It is usually advantageous to use information regarding historical floods, if available, to define the flood-frequency relation for a stream. Peak stages can sometimes be determined for outstanding floods that occurred many years ago before systematic gaging of streams began. In the United States, this information is usually not available for more than 100-200 years, but in countries with long cultural histories, such as China, historical flood data are available at some sites as far back as 2,000 years or more. It is important in flood studies to be able to assign a maximum discharge rate and an associated error range to the historical flood. This paper describes the significant characteristics and uncertainties of four commonly used methods for estimating the peak discharge of a flood. These methods are: (1) rating curve (stage-discharge relation) extension; (2) slope conveyance; (3) slope area; and (4) step backwater. Logarithmic extensions of rating curves are based on theoretical plotting techniques that results in straight line extensions provided that channel shape and roughness do not change significantly. The slope-conveyance and slope-area methods are based on the Manning equation, which requires specific data on channel size, shape and roughness, as well as the water-surface slope for one or more cross-sections in a relatively straight reach of channel. The slope-conveyance method is used primarily for shaping and extending rating curves, whereas the slope-area method is used for specific floods. The step-backwater method, also based on the Manning equation, requires more cross-section data than the slope-area ethod, but has a water-surface profile convergence characteristic that negates the need for known or estimated water-surface slope. Uncertainties in calculating peak discharge for historical floods may be quite large. Various investigations have shown that errors in calculating peak discharges by the slope-area method under ideal conditions for recent floods (i.e., when flood elevations, slope and channel characteristics are reasonably certain), may be on the order of 10-25%. Under less than ideal conditions, where streams are hydraulically steep and rough, errors may be much larger. The additional uncertainties for historical floods created by the passage of time may result in even larger errors of peak discharge. ?? 1987.

Seasonality in Violent and Nonviolent Methods of Suicide Attempts: A Cross-Sectional Study on Systematic Registry Data.

PubMed

Veisani, Yousef; Delpisheh, Ali; Sayehmiri, Kourosh; Moradi, Ghobad; Hassanzadeh, Jafar

2017-08-01

Little attention has been paid to seasonality in suicide in Iran. Time pattern in suicide deaths and suicide attempts for some related factors such as gender, mental disorders has been found. In present study, we focus on suicide methods and the association with seasonality and other putative covariates such as gender. Through a cross-sectional study, overall identified suicide attempts and suicide deaths in the province of Ilam from 1 January 2010 and 31 December 2014 were enrolled. We used Edwards' test for test of seasonality in suicide methods. Seasonal effect (peak/trough seasons) and (deaths/attempts suicide) was explored by ratio statistics, the null hypothesis being that the attempted suicides in each method group are evenly distributed over a year. More suicide attempts by hanging 29.4% and self-immolation 41.4% were observed in spring and differ by season pattern in both genders. The overall distribution of suicides by violent and non-violent methods was (males x2=6.3, P=0.041, females x2=7.7, P=0.021) and (males x2=44.5, P=0.001, females x2=104.7, P=0.001), respectively. The peak and trough seasons was observed in taking medications and self-poisoning for spring and winter. Suicide with alcohol was no differ by season pattern (x2=1.0, P=0.460). Suicide in Ilam illustrates a significant seasonality for both violent and non-violent methods of suicide, in both genders, the two peaks were observed in spring and autumn for violent suicides, and spring and summer in non-violent suicides.

Relationship between strength, power, speed, and change of direction performance of female softball players.

PubMed

Nimphius, Sophia; McGuigan, Michael R; Newton, Robert U

2010-04-01

The purpose of this study was to investigate (a) the cross-sectional relationship of strength, power, and performance variables in trained female athletes and (b) determine if the relationship between these variables changes over the course of a season. Ten female softball players (age = 18.1 +/- 1.6 years, height = 166.5 +/- 8.9 cm, and weight = 72.4 +/- 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower body strength (one repetition maximum [1RM]), peak force (PF), peak velocity (PV), and peak power (PP) during jump squats unloaded and loaded, unloaded countermovement vertical jump height (VJH) 1 base and 2 base sprint performance and change of direction performance on dominant and nondominant sides. The testing sessions occurred pre, mid, and post a 20-week training period. Relationship between body weight (BW), relative strength (1RM/BW), VJH, relative PP, relative PF, PV, speed, and change of direction variables were assessed by Pearson product-moment correlation coefficient at each testing session. Significant relationships were found across all time points with BW, speed, and change of direction measures (r = 0.70-0.93) and relative strength and measures of speed and change of direction ability (r = -0.73-0.85). There were no significant relationships between VJH and any measure of performance at any time point. In conclusion, BW and relative strength have strong to very strong correlations with speed and change of direction ability, and these correlations remain consistent over the course of the season. However, it seems as if many relationships vary with time, and their relationships should therefore be investigated longitudinally to better determine if these cross-sectional relationships truly reflect a deterministic relationship.

Tensile properties of the transverse carpal ligament and carpal tunnel complex.

PubMed

Ugbolue, Ukadike C; Gislason, Magnus K; Carter, Mark; Fogg, Quentin A; Riches, Philip E; Rowe, Philip J

2015-08-01

A new sophisticated method that uses video analysis techniques together with a Maillon Rapide Delta to determine the tensile properties of the transverse carpal ligament-carpal tunnel complex has been developed. Six embalmed cadaveric specimens amputated at the mid-forearm and aged (mean (SD)): 82 (6.29) years were tested. The six hands were from three males (four hands) and one female (two hands). Using trigonometry and geometry the elongation and strain of the transverse carpal ligament and carpal arch were calculated. The cross-sectional area of the transverse carpal ligament was determined. Tensile properties of the transverse carpal ligament-carpal tunnel complex and Load-Displacement data were also obtained. Descriptive statistics, one-way ANOVA together with a post-hoc analysis (Tukey) and t-tests were incorporated. A transverse carpal ligament-carpal tunnel complex novel testing method has been developed. The results suggest that there were no significant differences between the original transverse carpal ligament width and transverse carpal ligament at peak elongation (P=0.108). There were significant differences between the original carpal arch width and carpal arch width at peak elongation (P=0.002). The transverse carpal ligament failed either at the mid-substance or at their bony attachments. At maximum deformation the peak load and maximum transverse carpal ligament displacements ranged from 285.74N to 1369.66N and 7.09mm to 18.55mm respectively. The transverse carpal ligament cross-sectional area mean (SD) was 27.21 (3.41)mm(2). Using this method the results provide useful biomechanical information and data about the tensile properties of the transverse carpal ligament-carpal tunnel complex. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combining axial and radial nanowire heterostructures: radial Esaki diodes and tunnel field-effect transistors.

PubMed

Dey, Anil W; Svensson, Johannes; Ek, Martin; Lind, Erik; Thelander, Claes; Wernersson, Lars-Erik

2013-01-01

The ever-growing demand on high-performance electronics has generated transistors with very impressive figures of merit (Radosavljevic et al., IEEE Int. Devices Meeting 2009, 1-4 and Cho et al., IEEE Int. Devices Meeting 2011, 15.1.1-15.1.4). The continued scaling of the supply voltage of field-effect transistors, such as tunnel field-effect transistors (TFETs), requires the implementation of advanced transistor architectures including FinFETs and nanowire devices. Moreover, integration of novel materials with high electron mobilities, such as III-V semiconductors and graphene, are also being considered to further enhance the device properties (del Alamo, Nature 2011, 479, 317-323, and Liao et al., Nature 2010, 467, 305-308). In nanowire devices, boosting the drive current at a fixed supply voltage or maintaining a constant drive current at a reduced supply voltage may be achieved by increasing the cross-sectional area of a device, however at the cost of deteriorated electrostatics. A gate-all-around nanowire device architecture is the most favorable electrostatic configuration to suppress short channel effects; however, the arrangement of arrays of parallel vertical nanowires to address the drive current predicament will require additional chip area. The use of a core-shell nanowire with a radial heterojunction in a transistor architecture provides an attractive means to address the drive current issue without compromising neither chip area nor device electrostatics. In addition to design advantages of a radial transistor architecture, we in this work illustrate the benefit in terms of drive current per unit chip area and compare the experimental data for axial GaSb/InAs Esaki diodes and TFETs to their radial counterparts and normalize the electrical data to the largest cross-sectional area of the nanowire, i.e. the occupied chip area, assuming a vertical device geometry. Our data on lateral devices show that radial Esaki diodes deliver almost 7 times higher peak current, Jpeak = 2310 kA/cm(2), than the maximum peak current of axial GaSb/InAs(Sb) Esaki diodes per unit chip area. The radial TFETs also deliver high peak current densities Jpeak = 1210 kA/cm(2), while their axial counterparts at most carry Jpeak = 77 kA/cm(2), normalized to the largest cross-sectional area of the nanowire.

A sub-GeV charged-current quasi-elastic $$\

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

Walding, Joseph James

2009-12-01

Neutrino-nucleus charged-current quasi-elastic scattering is the signal interaction used by many neutrino oscillation experiments. For muon disappearance studies the signal mode is ν μn → μp. Modern oscillation experiments, such as T2K, produce neutrino beams with peak beam energies of order a few-GeV. It is therefore vitally important to have accurate measurements of the charged-current quasi-elastic crosssection for future neutrino oscillation experiments. Neutrino-nucleus cross-sections in the few-GeV region are not well understood, with the main uncertainties coming from understanding of the neutrino beam flux and the final state interactions within nuclei. SciBooNE is a sub-GeV neutrino-nucleus cross-section experiment based atmore » Fermilab, Batavia, USA, with the goal to measure neutrino cross-sections with precision of order 5%. SciBooNE took data from June 2007 until August 2008, in total 0.99×10 20 and 1.53×10 20 protons on target were collected in neutrino and anti-neutrino mode, respectively. In this thesis a ν μ charged-current quasi-elastic (CCQE) cross-section contained within the SciBar sub-detector is presented. A method to tag muons in SciBar was developed and three samples were isolated. An excess in backwards tracks in the one-track sample is observed. A Poisson maximum likelihood is used to extract the CCQE cross-section. The fit was applied using a basic fit parameter model, successfully used to obtain the cross-section in the SciBar-MRD matched CCQE analysis. This method was found to be insufficient in describing the data for the SciBarcontained CCQE analysis. By adding two migration parameters the cross-section was calculated to be 1.004 ± 0.031 (stat) +0.101 -0.150(sys) × 10 -38 cm 2/neutron, excluding backwards tracks with a χ 2 = 203.8/76 d.o.f. and 1.083 ± 0.030(stat) +0.115 -0.177(sys) × 10 -38 cm 2/neutron, including backwards tracks with a χ 2 = 659.8/133 d.o.f. Only neutrino beam and detector systematics have been considered. Further study of the SciBar-contained sample is suggested, introducing additional fit parameters and considering the remaining systematics. The end goal is to extract a SciBooNE CCQE cross-section using the SciBar-contained and SciBar-MRD matched samples.« less

Genetic and Dynamic Analyses of Murine Peak Bone Density

DTIC Science & Technology

1999-10-01

DAMD17-96-1-6309 differences, the location of bone regulatory genes with strong and modifier effects , the mode of inheritance for each gene, the...estimate the cortical cross-sectional area, most likely due to partial volume effects . Thus, the high density bone area was consistently estimated to be...significant or highly significant linkage with BMD; b) 9 Beamer, WG DAMD17-96-1-6309 none of the loci exhibited significant interaction effects by ANOVA

Research Laboratory of Electronics Annual Report Number 125.

DTIC Science & Technology

1983-01-01

Picosecond Optics 35 7.4 Ultrashort Pulse Formation 37 7.5 Ferntosecond Laser System 37 7.6 Parametric Scattering with Femtosecond Pulses 38 7.7 Near-IR...ionization of atomic hydrogen as calculated by 10 Reinhardt for a single frequency laser . To facilitate comparison, the cross section has been divided by 13...As the intensity increases, the peaks shift to the blue and become broader. Figure 3-3: Ionization profiles produced by laser intensity 10 and at five

The Structure and Reactivity of Alkylsiloxane Monolayers Formed by Reaction of Alkyltrichlorosilanes on Silicon Substrates

DTIC Science & Technology

1989-05-01

approximately true, theoretical and experimental studies indicate that roughnesses below 50 A (peak to valley) should have little effect on the...52 - 72. These sensitivities are those supplied by Surface Science Laboratories in the ESCA 8.OB software. They are the photoionization cross...sections calculated by Scofield , corrected for the dependence of the escape depth of an electron on its energy. Scofield , J. H. . Electon S 1976, IL, 129

Quantum treatment of the capture of an atom by a fast nucleus incident on a molecule

NASA Astrophysics Data System (ADS)

Shakeshaft, Robin; Spruch, Larry

1980-04-01

The classical double-scattering model of Thomas for the capture of electrons from atoms by fast ions yields a cross section σ which dominates over the single scattering contribution for sufficiently fast ions. The magnitude of the classical double-scattering σ differs, however, from its quantum-mechanical (second-Born) analog by an order of magnitude. Further, a "fast ion" means an ion of some MeV, and at those energies the cross sections are very low. On the other hand, as noted by Bates, Cook, and Smith, the double-scattering cross section for the capture of atoms from molecules by fast ions dominates over the single-scattering contribution for incident ions of very much lower energy; roughly, one must have the velocity of the incident projectile much larger than a characteristic internal velocity of the particles in the target. It follows that we are in the asymptotic domain not at about 10 MeV but at about 100 eV. For the reaction H+ + CH4-->H+2 + CH3 with incident proton energies of 70 to 150 eV, the peak in the angular distribution as determined experimentally is at almost precisely the value predicted by the classical model, but the theoretical total cross section is about 30 times too large. Using a quantum version of the classical model, which involves the same kinematics and therefore preserves the agreement with the angular distribution, we obtain somewhat better agreement with the experimental total cross section, by a factor of about 5. (To obtain very good agreement, one may have to perform a really accurate calculation of large-angle elastic scattering of protons and H atoms by CH3, and take into account interference effects.) In the center-of-mass frame, for sufficiently high incident energy, the first of the two scatterings involves the scattering of H+ by H through an angle of very close to 90°, and it follows that the nuclei of the emergent H+2 ion will almost all be in the singlet state. We have also calculated the cross section for the reaction D+ + CH4-->(HD)+ + CH3.

Triple Differential Cross Sections for single ionization of the Ethane molecule

NASA Astrophysics Data System (ADS)

Ali, Esam; Nixon, Kate; Ning, Chuangang; Murray, Andrew; Madison, Don

2015-09-01

We report experimental and theoretical results for electron-impact (e,2e) ionization of the Ethane molecule (C2H6) in the coplanar scattering geometry for four different ejected electron energies Ea = 5,10,15, and 20 eV respectively, and for each ejected electron energy, the projectile scattering angle is fixed at 10°. We will show that the TDCS is very sensitive for the case of two heavy nuclei surrounded by lighter H nuclei. On the theoretical side, we have used the M3DW coupled with the Orientation Averaged Molecular Orbital (OAMO) approximation and proper average (PA) over all orientations. These approximations show good agreement with experimental data for the binary peaks. However, for the recoil peak region, experiment finds a noticeable peak while theory predicts no peak. No recoil peak suggests no (or very weak) nuclear scattering, so we have investigated the importance of nuclear scattering by moving the nuclei closer to the center of mass. This work is supported by the US National Science Foundation under Grant No. PHY-1068237 and XSEDE resources provided by the Texas Advanced Computing Center (Grant No. TG-MCA07S029).

The modelling of symmetric airfoil vortex generators

NASA Technical Reports Server (NTRS)

Reichert, B. A.; Wendt, B. J.

1996-01-01

An experimental study is conducted to determine the dependence of vortex generator geometry and impinging flow conditions on shed vortex circulation and crossplane peak vorticity for one type of vortex generator. The vortex generator is a symmetric airfoil having a NACA 0012 cross-sectional profile. The geometry and flow parameters varied include angle-of-attack alfa, chordlength c, span h, and Mach number M. The vortex generators are mounted either in isolation or in a symmetric counter-rotating array configuration on the inside surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio is delta/R = 0. 17. Circulation and peak vorticity data are derived from crossplane velocity measurements conducted at or about 1 chord downstream of the vortex generator trailing edge. Shed vortex circulation is observed to be proportional to M, alfa, and h/delta. With these parameters held constant, circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio AR. Shed vortex peak vorticity is also observed to be proportional to M, alfa, and h/delta. Unlike circulation, however, peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at AR approx. 2.0 before falling off.

Observation of pi+pi-pi+pi- photoproduction in ultraperipheral heavy-ion collisions at sqrt sNN = 200 GeV at the STAR detector

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

STAR Collaboration; Abelev, Betty

We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultra-peripheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2},more » in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.} {+-} 4.4{sub syst.}%.« less

Observation of pi+ pi- pi+pi- photoproduction in ultraperipheral heavy-ion collisons at sqrt sNN = 200 GeV at the STAR Detector

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

Abelev, B.I.; Dunlop, J.; et al. STAR Collaboration

We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultraperipheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2},more » in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.}{+-}4.4{sub syst.}%.« less

Evidence for ACTN3 as a Speed Gene in Isolated Human Muscle Fibers.

PubMed

Broos, Siacia; Malisoux, Laurent; Theisen, Daniel; van Thienen, Ruud; Ramaekers, Monique; Jamart, Cécile; Deldicque, Louise; Thomis, Martine A; Francaux, Marc

2016-01-01

To examine the effect of α-actinin-3 deficiency due to homozygosity for the ACTN3 577X-allele on contractile and morphological properties of fast muscle fibers in non-athletic young men. A biopsy was taken from the vastus lateralis of 4 RR and 4 XX individuals to test for differences in morphologic and contractile properties of single muscle fibers. The cross-sectional area of the fiber and muscle fiber composition was determined using standard immunohistochemistry analyses. Skinned single muscle fibers were subjected to active tests to determine peak normalized force (P0), maximal unloading velocity (V0) and peak power. A passive stretch test was performed to calculate Young's Modulus and hysteresis to assess fiber visco-elasticity. No differences were found in muscle fiber composition. The cross-sectional area of type IIa and IIx fibers was larger in RR compared to XX individuals (P<0.001). P0 was similar in both groups over all fiber types. A higher V0 was observed in type IIa fibers of RR genotypes (P<0.001) but not in type I fibers. The visco-elasticity as determined by Young's Modulus and hysteresis was unaffected by fiber type or genotype. The greater V0 and the larger fast fiber CSA in RR compared to XX genotypes likely contribute to enhanced whole muscle performance during high velocity contractions.

A Priori Method of Using Photon Activation Analysis to Determine Unknown Trace Element Concentrations in NIST Standards

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

Green, Jaromy; Sun Zaijing; Wells, Doug

2009-03-10

Photon activation analysis detected elements in two NIST standards that did not have reported concentration values. A method is currently being developed to infer these concentrations by using scaling parameters and the appropriate known quantities within the NIST standard itself. Scaling parameters include: threshold, peak and endpoint energies; photo-nuclear cross sections for specific isotopes; Bremstrahlung spectrum; target thickness; and photon flux. Photo-nuclear cross sections and energies from the unknown elements must also be known. With these quantities, the same integral was performed for both the known and unknown elements resulting in an inference of the concentration of the un-reported elementmore » based on the reported value. Since Rb and Mn were elements that were reported in the standards, and because they had well-identified peaks, they were used as the standards of inference to determine concentrations of the unreported elements of As, I, Nb, Y, and Zr. This method was tested by choosing other known elements within the standards and inferring a value based on the stated procedure. The reported value of Mn in the first NIST standard was 403{+-}15 ppm and the reported value of Ca in the second NIST standard was 87000 ppm (no reported uncertainty). The inferred concentrations were 370{+-}23 ppm and 80200{+-}8700 ppm respectively.« less

Using Combined Diagnostic Test Results to Hindcast Trends of Infection from Cross-Sectional Data

PubMed Central

Rydevik, Gustaf; Innocent, Giles T.; Marion, Glenn; White, Piran C. L.; Billinis, Charalambos; Barrow, Paul; Mertens, Peter P. C.; Gavier-Widén, Dolores; Hutchings, Michael R.

2016-01-01

Infectious disease surveillance is key to limiting the consequences from infectious pathogens and maintaining animal and public health. Following the detection of a disease outbreak, a response in proportion to the severity of the outbreak is required. It is thus critical to obtain accurate information concerning the origin of the outbreak and its forward trajectory. However, there is often a lack of situational awareness that may lead to over- or under-reaction. There is a widening range of tests available for detecting pathogens, with typically different temporal characteristics, e.g. in terms of when peak test response occurs relative to time of exposure. We have developed a statistical framework that combines response level data from multiple diagnostic tests and is able to ‘hindcast’ (infer the historical trend of) an infectious disease epidemic. Assuming diagnostic test data from a cross-sectional sample of individuals infected with a pathogen during an outbreak, we use a Bayesian Markov Chain Monte Carlo (MCMC) approach to estimate time of exposure, and the overall epidemic trend in the population prior to the time of sampling. We evaluate the performance of this statistical framework on simulated data from epidemic trend curves and show that we can recover the parameter values of those trends. We also apply the framework to epidemic trend curves taken from two historical outbreaks: a bluetongue outbreak in cattle, and a whooping cough outbreak in humans. Together, these results show that hindcasting can estimate the time since infection for individuals and provide accurate estimates of epidemic trends, and can be used to distinguish whether an outbreak is increasing or past its peak. We conclude that if temporal characteristics of diagnostics are known, it is possible to recover epidemic trends of both human and animal pathogens from cross-sectional data collected at a single point in time. PMID:27384712

Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity

USGS Publications Warehouse

Wobus, C.W.; Kean, J.W.; Tucker, G.E.; Anderson, R. Scott

2008-01-01

The cross-sectional shape of a natural river channel controls the capacity of the system to carry water off a landscape, to convey sediment derived from hillslopes, and to erode its bed and banks. Numerical models that describe the response of a landscape to changes in climate or tectonics therefore require formulations that can accommodate evolution of channel cross-sectional geometry. However, fully two-dimensional (2-D) flow models are too computationally expensive to implement in large-scale landscape evolution models, while available simple empirical relationships between width and discharge do not adequately capture the dynamics of channel adjustment. We have developed a simplified 2-D numerical model of channel evolution in a cohesive, detachment-limited substrate subject to steady, unidirectional flow. Erosion is assumed to be proportional to boundary shear stress, which is calculated using an approximation of the flow field in which log-velocity profiles are assumed to apply along vectors that are perpendicular to the local channel bed. Model predictions of the velocity structure, peak boundary shear stress, and equilibrium channel shape compare well with predictions of a more sophisticated but more computationally demanding ray-isovel model. For example, the mean velocities computed by the two models are consistent to within ???3%, and the predicted peak shear stress is consistent to within ???7%. Furthermore, the shear stress distributions predicted by our model compare favorably with available laboratory measurements for prescribed channel shapes. A modification to our simplified code in which the flow includes a high-velocity core allows the model to be extended to estimate shear stress distributions in channels with large width-to-depth ratios. Our model is efficient enough to incorporate into large-scale landscape evolution codes and can be used to examine how channels adjust both cross-sectional shape and slope in response to tectonic and climatic forcing. Copyright 2008 by the American Geophysical Union.

Spectroscopic study of the Lambda hypernuclei by the (e,e'K +) reaction

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

Miyoshi, Toshinobu

Hypernuclear spectroscopy study via the (e,e'K +) reaction has been carried out for the first time, establishing a new technique to study Lambda hypernuclei. The high quality electron beam at Jefferson Lab made it possible to measure Lambda hypernuclear spectra with an energy resolution better than 1 MeV (FWHM). The present experiment was designed to make full use of the virtual photon flux, which peaks at very forward angles, by detecting scattered electrons at 0 degrees. Scattered positive kaons were also detected near 0 degrees, where the cross section of the kaon photo-production is maximized. This unique kinematical configuration was realized with the HyperNuclear Spectrometer System (HNSS), which consisted of the Short-Orbit Spectrometer, the Enge Split-Pole Spectrometer, and the splitter magnet. Themore » $$12\\atop{Λ}$$B mass spectrum was measured in the 12C(e,e'K +)$$12\\atop{Λ}$$ reaction with 0.9 MeV (FWHM) energy resolution. The averaged binding energy of the $$12\\atop{Λ}$$B ground state doublet was obtained to be 11.7 ± 0.1 (statistical) ± 0.3 (systematic) MeV, which is consistent with emulsion data. The general spectral structure of the 12C(e,e'K +) $$12\\atop{Λ}$$B reaction was found to be similar to that of the 12C(Λ +,K +)$$12\\atop{Λ}$$C reaction, showing characteristic peaks corresponding to sLambda and pLambda orbits, as well as a few core-excited states. The cross section of the $$12\\atop{Λ}$$B ground state doublet was derived to be 117 ± 13 (statistical) ± 14 (systematic) nb/sr. The theoretical prediction of the cross section was consistent with the present result, validating DWIA calculation for hypernuclear yields. The present study proved the effectiveness of the (e,e'K +) reaction for future Lambda hypernuclear spectroscopy studies.« less

Influence of breakup on elastic and α-production channels in the 6Li+ 116Sn reaction

NASA Astrophysics Data System (ADS)

Patel, D.; Mukherjee, S.; Deshmukh, N.; Lubian, J.; Wang, Jian-Song; Correa, T.; Nayak, B. K.; Yang, Yan-Yun; Ma, Wei-Hu; Biswas, D. C.; Gupta, Y. K.; Santra, S.; Mirgule, E. T.; Danu, L. S.; Singh, N. L.; Saxena, A.

2017-10-01

The effects of breakup reactions on elastic and α-production channels for the 6Li+116Sn system have been investigated at energies below and near the Coulomb barrier. The angular distributions of α-particle production differential cross sections have been obtained at several projectile energies between 22 and 40 MeV. The measured breakup α-particle differential cross sections and elastic scattering angular distributions have been compared with the predictions of continuum-discretized coupled channels (CDCC) calculations. The influence of breakup coupling has also been investigated by extracting dynamic polarization potentials (DPP) from the CDCC calculations. From the predictions of CDCC calculations the relative importance of the nuclear, Coulomb, and total breakup contributions have also been investigated. The nuclear breakup couplings are observed to play an important role in comparison to the Coulomb breakup for the direct breakup mechanisms associated in the reaction of 6Li projectile with 116Sn target nuclei. The influence of strong nuclear breakup coupling exhibits suppression in the Coulomb-nuclear interference peak. The direct breakup cross sections from the CDCC calculations under-predict the measured α-particle differential cross sections at all energies. This suggests that the measured α particles may also have contributions from other possible breakup reaction channels. One of the authors (SM) would like to thank DAE-BRNS for financial assistance through a major research project. This work is supported by National Natural Science Foundation of China (U1432247, 11575256, U1632138, 11605253) and China Postdoctoral Science Foundation (2016M602906)

Uptake of methanol on mixed HNO3/H2O clusters: An absolute pickup cross section

NASA Astrophysics Data System (ADS)

Pysanenko, A.; Lengyel, J.; Fárník, M.

2018-04-01

The uptake of atmospheric oxidized organics on acid clusters is relevant for atmospheric new particle formation. We investigate the pickup of methanol (CH3OH) on mixed nitric acid-water clusters (HNO3)M(H2O)N by a combination of mass spectrometry and cluster velocity measurements in a molecular beam. The mass spectra of the mixed clusters exhibit (HNO3)m(H2O)nH+ series with m = 0-3 and n = 0-12. In addition, CH3OH.(HNO3)m(H2O)nH+ series with very similar patterns appear in the spectra after the methanol pickup. The velocity measurements prove that the undoped (HNO3)m(H2O)nH+ mass peaks in the pickup spectra originate from the neutral (HNO3)M(H2O)N clusters which have not picked up any CH3OH molecule, i.e., methanol has not evaporated upon the ionization. Thus the fraction of the doped clusters can be determined and the mean pickup cross section can be estimated, yielding σs ¯ ≈ 20 Å2. This is compared to the lower estimate of the mean geometrical cross section σg ¯ ≈ 60 Å2 obtained from the theoretical cluster geometries. Thus the "size" of the cluster corresponding to the methanol pickup is at least 3-times smaller than its geometrical size. We have introduced a method which can yield the absolute pickup cross sections relevant to the generation and growth of atmospheric aerosols, as illustrated in the example of methanol and nitric acid clusters.

Double-differential cross section for ionization of H2O molecules by 4-MeV/u C6 + and Si13 + ions

NASA Astrophysics Data System (ADS)

Bhattacharjee, Shamik; Biswas, S.; Monti, J. M.; Rivarola, R. D.; Tribedi, L. C.

2017-11-01

Double-differential cross section (DDCS) for electrons ejected in collisions of fast C6 + and Si13 + projectiles, with a H2O vapor target, were measured. The electrons were detected over an energy range of 1-600 eV and an angular range of 20∘-160∘. The obtained DDCS spectra, for both the ions, were compared with the CDW-EIS model. Occasional reference has been made to the DDCS data for the case of 3.75-MeV/u O8 + colliding on the same molecule for an overall comparison. A reasonable agreement with theoretical results was seen for the case of C6 + and O8 + projectiles. However, between C6 + and O8 + projectiles, the deviation from theory is larger for the case of the carbon projectile. Substantial deviation starts to show up for the case of the Si13 + projectile. By numerical integration of the DDCS data, the single-differential cross section (SDCS) and total cross section (TCS) were obtained and compared with theoretical models. The present TCS data along with the other available data for p , He , and C ions were plotted together. A clear and gradual deviation from the Bethe-Born predicted q2 scaling was observed, where q is the projectile charge state. From all the data we find TCS varies as qn where n = 1.7 ± 0.1. The provided data set will be valuable in order to help model the radiation damage in hadron therapy, particularly in the Bragg peak region.

User-guided automated segmentation of time-series ultrasound images for measuring vasoreactivity of the brachial artery induced by flow mediation

NASA Astrophysics Data System (ADS)

Sehgal, Chandra M.; Kao, Yen H.; Cary, Ted W.; Arger, Peter H.; Mohler, Emile R.

2005-04-01

Endothelial dysfunction in response to vasoactive stimuli is closely associated with diseases such as atherosclerosis, hypertension and congestive heart failure. The current method of using ultrasound to image the brachial artery along the longitudinal axis is insensitive for measuring the small vasodilatation that occurs in response to flow mediation. The goal of this study is to overcome this limitation by using cross-sectional imaging of the brachial artery in conjunction with the User-Guided Automated Boundary Detection (UGABD) algorithm for extracting arterial boundaries. High-resolution ultrasound imaging was performed on rigid plastic tubing, on elastic rubber tubing phantoms with steady and pulsatile flow, and on the brachial artery of a healthy volunteer undergoing reactive hyperemia. The area of cross section of time-series images was analyzed by UGABD by propagating the boundary from one frame to the next. The UGABD results were compared by linear correlation with those obtained by manual tracing. UGABD measured the cross-sectional area of the phantom tubing to within 5% of the true area. The algorithm correctly detected pulsatile vasomotion in phantoms and in the brachial artery. A comparison of area measurements made using UGABD with those made by manual tracings yielded a correlation of 0.9 and 0.8 for phantoms and arteries, respectively. The peak vasodilatation due to reactive hyperemia was two orders of magnitude greater in pixel count than that measured by longitudinal imaging. Cross-sectional imaging is more sensitive than longitudinal imaging for measuring flow-mediated dilatation of brachial artery, and thus may be more suitable for evaluating endothelial dysfunction.

Defect formation in MeV H+ implanted GaN and 4H-SiC investigated by cross-sectional Raman spectroscopy

NASA Astrophysics Data System (ADS)

Huang, Kai; Jia, Qi; You, Tiangui; Zhang, Shibin; Lin, Jiajie; Zhang, Runchun; Zhou, Min; Yu, Wenjie; Zhang, Bo; Ou, Xin; Wang, Xi

2017-09-01

Cross-sectional Raman spectroscopy is used to characterize the defect formation and the defect recovery in MeV H+ implanted bulk GaN and 4H-SiC in the high energy MeV ion-cut process. The Raman intensity decreases but the forbidden modes are activated at the damage region, and the intensity decrease is proportional to the damage level. The Raman spectrum is quite sensitive to detect the damage recovery after annealing. The main peak intensity increases and the forbidden mode disappears in both annealed GaN and 4H-SiC samples. The Raman spectra of GaN samples annealed at different temperatures suggest that higher annealing temperature is more efficient for damage recovery. While, the Raman spectra of SiC indicate that higher implantation temperature results in heavier lattice damage and other polytype clusters might be generated by high annealing temperature in the annealed SiC samples. The cross-sectional Raman spectroscopy is a straightforward method to characterize lattice damage and damage recovery in high energy ion-cut process. It can serve as a fast supplementary measurement technique to Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA) and transmission electron microscope (TEM) for the defect characterizations.

R-Matrix Analysis of the 13C(α,n)16O Reaction

NASA Astrophysics Data System (ADS)

Kock, Arthur; Rogachev, Grigory

2015-10-01

The 13C(α,n)16O reaction plays a crucial role in the main s-process occurring in low-mass thermally-pulsing asymptotic giant branch (TP-AGB) stars, which produces about half of all nuclei heavier than iron. However, direct measurements of this reaction cross section near the Gamow-peak energy are currently not possible due to very small reaction cross sections. Additionally, available cross-section data at higher energy have some inconsistencies, leading to significant uncertainties in low energy extrapolations. A global R-matrix fit was conducted, using all available data for the 13C(α,n)16O, 13C(α, α)13C, and 16O(n,n)16O reactions. Of particular importance was the inclusion of the fixed ANC for the 1 / 2 + state at 6 . 356 MeV in 17O, which was measured recently using the sub-Coulomb α-transfer reaction, as well as the new 13C+ α elastic-scattering data measured in the low-energy region 1 . 6 - 3 . 8 MeV. Important constraining information on various resonances was found, and the uncertainty for the astrophysical 13C(α,n)16O reaction rate was dramatically reduced. Much work on the analysis was done by A. K. Nurmukhanbetova from National Laboratory Astana in Astana, Kazakhstan.

Nuclear Astrophysics in underground laboratories: the LUNA experiment

NASA Astrophysics Data System (ADS)

2017-11-01

One of the main ingredients of nuclear astrophysics is the knowledge of the thermonuclear reactions responsible for powering the stellar engine and for the synthesis of the chemical elements. At astrophysical energies the cross section of nuclear processes is extremely reduced by the effect of the Coulomb barrier. The low value of cross sections prevents their measurement at stellar energies on Earth surface and often extrapolations are needed. The Laboratory for Underground Nuclear Astrophysics (LUNA) is placed under the Gran Sasso mountain and thanks to the cosmic-ray background reduction provided by its position can investigate cross sections at energies close to the Gamow peak in stellar scenarios. Many crucial reactions involved in hydrogen burning has been measured directly at astrophysical energies with both the LUNA-50kV and the LUNA-400kV accelerators, and this intense work will continue with the installation of a MV machine able to explore helium and carbon burnings. Based on this progress, currently there are efforts in several countries to construct new underground accelerators. In this talk, the typical techniques adopted in underground nuclear astrophysics will be described and the most relevant results achieved by LUNA will be reviewed. The exciting science that can be probed with the new facilities will be highlighted.

Hydrogen burning of oxygen-17

NASA Astrophysics Data System (ADS)

Newton, Joseph

Classical novae are explosive binary systems involving the accretion of hydrogen rich material from a main sequence star onto the surface of a white dwarf partner, reaching peak temperatures of T = 0.1-0.4 GK. Observed elemental abundances from the ejecta provide much needed constraints for the modeling of these explosions. Novae are thought to be the most significant source of 15 N and 17 O in the universe. The 17 O(p,g) 18 F and 17 O(p,g) 14 N reactions have an important effect on nucleosynthesis in novae, since they determine the creation and destruction of 17 O and 18 F, which produces detectable g- radiation. The dominant contributor to the 17 O(p,g) 14 N reaction is a resonance at [Special characters omitted.] = 193 keV. The strength of this resonance has been measured and the results are presented. For the 17 O(p,g) 18 F reaction, the dominant contribution comes from the nonresonant direct capture process. The literature direct capture cross sections currently differ by a factor of two. This cross section has been measured in the current work and the results are also presented. New reaction rates have been calculated with these measured cross sections using a new Monte Carlo technique and these new rates have significantly reduced uncertainties compared to the current literature.

Sources and routing of the Amazon River Flood Wave

NASA Astrophysics Data System (ADS)

Richey, Jeffrey E.; Mertes, Leal A. K.; Dunne, Thomas; Victoria, Reynaldo L.; Forsberg, Bruce R.; Tancredi, AntôNio C. N. S.; Oliveira, Eurides

1989-09-01

We describe the sources and routing of the Amazon River flood wave through a 2000-km reach of the main channel, between São Paulo de Olivença and Obidos, Brazil. The damped hydrograph of the main stem reflects the large drainage basin area, the 3-month phase lag in peak flows between the north and south draining tributaries due to seasonal differences in precipitation, and the large volume of water stored on the floodplain. We examined several aspects of the valley floor hydrology that are important for biogeochemistry. These include volumes of water storage in the channel and the floodplain and the rates of transfer between these two storage elements at various seasons and in each segment of the valley. We estimate that up to 30% of the water in the main stem is derived from water that has passed through the floodplain. To predict the discharge at any cross section within the study reach, we used the Muskingum formula to predict the hydrograph at downriver cross sections from a known hydrograph at upstream cross-sections and inputs and outputs along each reach. The model was calibrated using three years of data and was successfully tested against an additional six years of data. With this model it is possible to interpolate discharges for unsampled times and sites.

Prevalence of low back disorders among female workers and biomechanical limits on the handling of load and patients.

PubMed

Gutiérrez, Manuel; Monzó, Jorge

2012-01-01

The purpose of this investigation was to determine the association between prevalence of low back disorders in female workers and biomechanical demands of compressive and shear forces at the lumbar spine. A descriptive, cross-sectional and correlational study was carried out in 11 groups of female workers in the Province of Concepción. An interview was performed to investigate the prevalence of low back pain. To estimate biomechanical demands on the lumbar spine, it was used the 3DSSPP software. The Pearson correlation coefficient between the prevalence of low back disorders and peak compression force at the lumbar spine was r = (p<0.005). The Spearman correlation coefficient between the prevalence of low back disorders and peak shear force was r = 0.9 (p <0.005). To protect 90% of female workers studied, the limits of compression and shear forces should be at 2.8 kN and 0.3 kN, respectively. These values differ from the recommendations currently used, 3.4 kN for peak compression force and 0.5 kN for peak shear force.

Role of the triangle singularity in Λ (1405 ) production in the π-p →K0π Σ and p p →p K+π Σ processes

NASA Astrophysics Data System (ADS)

Bayar, M.; Pavao, R.; Sakai, S.; Oset, E.

2018-03-01

We have investigated the cross section for the π-p →K0π Σ and p p →p K+π Σ reactions, paying attention to a mechanism that develops a triangle singularity. The triangle diagram is realized by the decay of a N* to K*Σ and the K* decay into π K , and the π Σ finally merges into Λ (1405 ) . The mechanism is expected to produce a peak around 2140 MeV in the K Λ (1405 ) invariant mass. We found that a clear peak appears around 2100 MeV in the K Λ (1405 ) invariant mass, which is about 40 MeV lower than the expectation, and that is due to the resonance peak of a N* resonance which plays a crucial role in the K*Σ production. The mechanism studied produces the peak of the Λ (1405 ) around or below 1400 MeV, as is seen in the p p →p K+π Σ HADES experiment.

Quasi-four-body treatment of charge transfer in the collision of protons with atomic helium: I. Thomas related mechanisms

NASA Astrophysics Data System (ADS)

Safarzade, Zohre; Fathi, Reza; Shojaei Akbarabadi, Farideh; Bolorizadeh, Mohammad A.

2018-04-01

The scattering of a completely bare ion by atoms larger than hydrogen is at least a four-body interaction, and the charge transfer channel involves a two-step process. Amongst the two-step interactions of the high-velocity single charge transfer in an anion-atom collision, there is one whose amplitude demonstrates a peak in the angular distribution of the cross sections. This peak, the so-called Thomas peak, was predicted by Thomas in a two-step interaction, classically, which could also be described through three-body quantum mechanical models. This work discusses a four-body quantum treatment of the charge transfer in ion-atom collisions, where two-step interactions illustrating a Thomas peak are emphasized. In addition, the Pauli exclusion principle is taken into account for the initial and final states as well as the operators. It will be demonstrated that there is a momentum condition for each two-step interaction to occur in a single charge transfer channel, where new classical interactions lead to the Thomas mechanism.

Rate of muscle contraction is associated with cognition in women, not in men.

PubMed

Tian, Qu; Osawa, Yusuke; Resnick, Susan M; Ferrucci, Luigi; Studenski, Stephanie A

2018-05-08

In older persons, lower hand grip strength is associated with poorer cognition. Little is known about how the rate of muscle contraction relates to cognition and upper extremity motor function, and sex differences are understudied. Linear regression, adjusting for age, race, education, body mass index, appendicular lean mass, and knee pain assessed sex-specific cross-sectional associations of peak torque, rate of torque development (RTD) and rate of velocity development (RVD) with cognition and upper extremity motor function. In men (n=447), higher rate-adjusted peak torque and a greater RVD were associated with faster simple finger tapping speed, and a greater RVD was associated with higher nondominant pegboard performance. In women (n=447), higher peak torque was not associated with any measures, but a greater RTD was associated with faster simple tapping speed and higher language performance, and a greater RVD was associated with higher executive function, attention, memory, and nondominant pegboard performance. In women with low isokinetic peak torque, RVD was associated with attention and memory. RVD capacity may reflect neural health, especially in women with low muscle strength.

Twentieth century arroyo changes in Chaco Culture National Historical Park

USGS Publications Warehouse

Gellis, Allen C.

2002-01-01

Chaco Wash arroyo channel changes in the 20th century have become a major concern of the National Park Service. Several archeologic and cultural sites are located in the Chaco Wash corridor; thus, increased erosional activity of Chaco Wash, such as channel incision and increased meandering, may affect these sites. Through field surveys, photogrammetric analyses, and reviews of existing reports and maps, arroyo changes at Chaco Culture National Historic Park were documented. Arroyo changes were documented for the inner active channel and the entire arroyo cross section. The inner channel of Chaco Wash evolved from a wide, braided channel in the 1930's to a narrower channel with a well-developed flood plain by the 1970's. From 1934 to 1973 the active channel narrowed an average of 26 meters, and from the 1970's to 2000 the channel narrowed an average of 9 meters. Overall from 1934 to 2000, the inner channel narrowed an average of 30 meters. From 1934 to 2000, the top of Chaco Wash widened at four cross sections, narrowed at one, and remained the same at another. The top of Chaco Wash widened at a rate of 0.4 meter per year from the 1970's to 2000 compared with 0.2 meter per year from 1934 to 1973. At 50-percent depth or halfway down the arroyo channel, four cross sections widened and two cross sections narrowed from 1934 to 2000. Rates of widening at 50-percent depth decreased from 0.2 meter per year from 1934 to 1973 to 0.1 meter per year from the 1970's to 2000. From 1934 to 2000, arroyo depth decreased at five of six cross sections and increased at one cross section. Arroyo depth between 1934 and 1973 decreased an average 1.4 meters from aggradation and between the 1970's and 2000 increased an average 0.4 meter from channel scour. From 1934 to 2000, arroyo cross-sectional area decreased at all six cross sections. Cross-sectional areas in Chaco Wash decreased from 1934 to 1973 as a result of sediment deposition and both decreased and increased from the 1970's to 2000. The cross-sectional area decreased by the 1970's due to channel narrowing and flood-plain formation. Increases in cross-sectional area are from channel scour and channel widening. Photogrammetric analyses of volumetric changes for a 1.7-kilometer reach of Chaco Wash showed sediment deposition from 1934 to 1973 of 64 square meters per unit length of channel over 1.7 kilometers to erosion from 1973 to 2000 of 7 square meters per unit length of channel. Chaco Wash evolved from a braided channel in the 1930's to a narrow, sinuous inner channel by the 1970's. Chaco Wash was widening in the 1930's, leading to sediment deposition and formation of an inner flood plain. Channel narrowing resulted from increased sediment deposition on the flood plain. Sediment deposition may be related to a decrease in peak flows, an increase in flood-plain vegetation, or an increase in the transport of fine-grained sediment. Increases in bankfull depth of Chaco Wash between the 1970's and 2000 were due to aggradation of the flood plain and channel scour. Thus, rates of aggradation and cross-sectional filling were greater from 1934 to the 1970's than from the 1970's to 2000.

High-resolution four-dimensional carbon-correlated 1H- 1H ROESY experiments employing isotags and the filter diagonalization method for effective assignment of glycosidic linkages in oligosaccharides

NASA Astrophysics Data System (ADS)

Armstrong, Geoffrey S.; Bendiak, Brad

2006-07-01

Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1H-1H ROESY cross peaks to two additional 13C frequency dimensions is reported. The 13C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter diagonalization method. The extensive overlap typically observed in 2D ROESY 1H-1H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1H-1H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1H-1H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.

High-resolution four-dimensional carbon-correlated 1H-1H ROESY experiments employing isotags and the filter diagonalization method for effective assignment of glycosidic linkages in oligosaccharides.

PubMed

Armstrong, Geoffrey S; Bendiak, Brad

2006-07-01

Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1H-1H ROESY cross peaks to two additional 13C frequency dimensions is reported. The 13C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter diagonalization method. The extensive overlap typically observed in 2D ROESY 1H-1H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1H-1H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1H-1H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.

Formation of lamellar cross bridges in the annulus fibrosus of the intervertebral disc is a consequence of vascular regression.

PubMed

Smith, Lachlan J; Elliott, Dawn M

2011-05-01

Cross bridges are radial structures within the highly organized lamellar structure of the annulus fibrosus of the intervertebral disc that connect two or more non-consecutive lamellae. Their origin and function are unknown. During fetal development, blood vessels penetrate deep within the AF and recede during postnatal growth. We hypothesized that cross bridges are the pathways left by these receding blood vessels. Initially, the presence of cross bridges was confirmed in cadaveric human discs aged 25 and 53 years. Next, L1-L2 intervertebral discs (n=4) from sheep ranging in age from 75 days fetal gestation to adult were processed for paraffin histology. Mid-sagittal sections were immunostained for endothelial cell marker PECAM-1. The anterior and posterior AF were imaged using differential interference contrast microscopy, and the following parameters were quantified: total number of distinct lamellae, total number of cross bridges, percentage of cross bridges staining positive for PECAM-1, cross bridge penetration depth (% total lamellae), and PECAM-1 positive cross bridge penetration depth. Cross bridges were first observed at 100 days fetal gestation. The overall number peaked in neonates then remained relatively unchanged. The percentage of PECAM-1 positive cross bridges declined progressively from almost 100% at 100 days gestation to less than 10% in adults. Cross bridge penetration depth peaked in neonates then remained unchanged at subsequent ages. Depth of PECAM-1 positive cross bridges decreased progressively after birth. Findings were similar for both the anterior and posterior. The AF lamellar architecture is established early in development. It later becomes disrupted as a consequence of vascularization. Blood vessels then recede, perhaps due to increasing mechanical stresses in the surrounding matrix. In this study we present evidence that the pathways left by receding blood vessels remain as lamellar cross bridges. It is unclear whether the presence of cross bridges in the aging and degenerating intervertebral disc would be advantageous or detrimental, and this question should be addressed by future studies. Copyright © 2011 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

Interference between extrinsic and intrinsic losses in x-ray absorption fine structure

NASA Astrophysics Data System (ADS)

Campbell, L.; Hedin, L.; Rehr, J. J.; Bardyszewski, W.

2002-02-01

The interference between extrinsic and intrinsic losses in x-ray absorption fine structure (XAFS) is treated within a Green's-function formalism, without explicit reference to final states. The approach makes use of a quasiboson representation of excitations and perturbation theory in the interaction potential between electrons and quasibosons. These losses lead to an asymmetric broadening of the main quasiparticle peak plus an energy-dependent satellite in the spectral function. The x-ray absorption spectra (XAS) is then given by a convolution of an effective spectral function over a one-electron cross section. It is shown that extrinsic and intrinsic losses tend to cancel near excitation thresholds, and correspondingly, the strength in the main peak increases. At high energies, the theory crosses over to the sudden approximation. These results thus explain the observed weakness of multielectron excitations in XAS. The approach is applied to estimate the many-body corrections to XAFS, beyond the usual mean-free path, using a phasor summation over the spectral function. The asymmetry of the spectral function gives rise to an additional many-body phase shift in the XAFS formula.

Synchronized vortex shedding and sound radiation from two side-by-side rectangular cylinders of different cross-sectional aspect ratios

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

Octavianty, Ressa, E-mail: ressa-octavianty@ed.tmu.ac.jp; Asai, Masahito, E-mail: masai@tmu.ac.jp

Synchronized vortex shedding from two side-by-side cylinders and the associated sound radiation were examined experimentally at Reynolds numbers of the order of 10{sup 4} in low-Mach-number flows. In addition to a pair of square cylinders, a pair of rectangular cylinders, one with a square cross section (d × d) and the other with a rectangular cross section (d × c) having a cross-sectional aspect ratio (c/d) of 1.2–1.5, was considered. The center-to-center distance between the two cylinders L/d was 3.6, 4.5, and 6.0; these settings were within the non-biased flow regime for side-by-side square cylinders. In case of a squaremore » cylinder pair, anti-phase synchronized vortex shedding occurring for L/d = 3.6 and 4.5 generated a quadrupole-like sound source which radiated in-phase, planar-symmetric sound in the far field. Synchronized vortex shedding from the two rectangular cylinders with different c/d also occurred with almost the same frequency as the characteristic frequency of the square-cylinder wake in the case of the small center-to-center distance, L/d = 3.6, for all the cylinder pairs examined. The synchronized sound field was anti-phase and asymmetric in amplitude, unlike the case of a square cylinder pair. For larger spacing L/d = 4.5, synchronized vortex shedding and anti-phase sound still occurred, but only for close cross-sectional aspect ratios (c/d = 1.0 and 1.2), and highly modulated sound was radiated with two different frequencies due to non-synchronized vortex shedding from the two cylinders for larger differences in c/d. It was also found that when synchronized vortex shedding occurred, near-wake velocity fluctuations exhibited high spanwise-coherency, with a very sharp spectral peak compared with the single-cylinder case.« less

Dynamic axial crushing of bitubular tubes with curvy polygonal inner-tube sections

NASA Astrophysics Data System (ADS)

Ahmed, Naveed; Xue, Pu; Zafar, Naeem

Bitubular structural configurations, where the outer tube is circular, square and curvy square in shape while the inner-tube section is curvy triangular, square and hexagonal in different proposed configurations, are numerically crushed under dynamic axial loading. The crashworthiness effectiveness for changing inner-tube polygonal cross-section for each of the outer tube sections is studied and compared with changing outer tube shape. The deformation plots and energy absorption (EA) parameters such as peak crushing force (PCF) mean crushing force (MCF), energy absorption and crush force efficiency for each case are evaluated. Most of the configurations showed ovalization with low PCF and MCF and moderate crush force efficiency. Afterwards, effects of L/D and t/R on deformation modes and EA are demonstrated by selecting one of the configurations from each group using published experimental results.

Structural parameters associated with location of peaks of peripapillary retinal nerve fiber layer thickness in young healthy eyes.

PubMed

Yamashita, Takehiro; Asaoka, Ryo; Kii, Yuya; Terasaki, Hiroto; Murata, Hiroshi; Sakamoto, Taiji

2017-01-01

The location of the peaks of the circumpapillary retinal nerve fiber layer (cpRNFL) thickness is affected by several ocular parameters. In this study, we have generated equations that can determine the peaks of the cpRNFL. This study was a prospective, observational, cross sectional study of 118 healthy right eyes. The axial length, optic disc tilt, superiortemporal (ST)- and inferiortemporal (IT)-peaks of the cpRNFL thickness, and angles of the ST and IT retinal arteries (RA) and veins (RV) were determined. The correlations between the location of the ST- and IT-peaks and ocular structural parameters and the sex, body height and weight were calculated. The best fit equations to generate the location of the ST/IT-peaks were determined using corrected-Akaike Information Criteria. The location of the ST-peak was 0.72+(0.40 x ST-RA)+(0.27 x ST-RV)+(0.14 x height)-(0.47 x papillo-macular-position)-(0.11 x disc tilt) with a coefficient of correlation of 0.61 (P<0.0001). The location of the IT-peak was 21.88+(0.53 x IT-RA)+(0.15 x IT-RV)+(0.041 x corneal thickness)-(1.00 x axial length) with a coefficient of correlation of 0.59 (P<0.0001). The location of ST/IT peaks is determined by different parameters of the ocular structure. These equations allow clinicians to obtain an accurate location of the peaks for a more accurate diagnosis of glaucoma.

New Evidence That Nonlinear Source-Filter Coupling Affects Harmonic Intensity and fo Stability During Instances of Harmonics Crossing Formants.

PubMed

Maxfield, Lynn; Palaparthi, Anil; Titze, Ingo

2017-03-01

The traditional source-filter theory of voice production describes a linear relationship between the source (glottal flow pulse) and the filter (vocal tract). Such a linear relationship does not allow for nor explain how changes in the filter may impact the stability and regularity of the source. The objective of this experiment was to examine what effect unpredictable changes to vocal tract dimensions could have on fo stability and individual harmonic intensities in situations in which low frequency harmonics cross formants in a fundamental frequency glide. To determine these effects, eight human subjects (five male, three female) were recorded producing fo glides while their vocal tracts were artificially lengthened by a section of vinyl tubing inserted into the mouth. It was hypothesized that if the source and filter operated as a purely linear system, harmonic intensities would increase and decrease at nearly the same rates as they passed through a formant bandwidth, resulting in a relatively symmetric peak on an intensity-time contour. Additionally, fo stability should not be predictably perturbed by formant/harmonic crossings in a linear system. Acoustic analysis of these recordings, however, revealed that harmonic intensity peaks were asymmetric in 76% of cases, and that 85% of fo instabilities aligned with a crossing of one of the first four harmonics with the first three formants. These results provide further evidence that nonlinear dynamics in the source-filter relationship can impact fo stability as well as harmonic intensities as harmonics cross through formant bandwidths. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Quantifying and predicting interpretational uncertainty in cross-sections

NASA Astrophysics Data System (ADS)

Randle, Charles; Bond, Clare; Monaghan, Alison; Lark, Murray

2015-04-01

Cross-sections are often constructed from data to create a visual impression of the geologist's interpretation of the sub-surface geology. However as with all interpretations, this vision of the sub-surface geology is uncertain. We have designed and carried out an experiment with the aim of quantifying the uncertainty in geological cross-sections created by experts interpreting borehole data. By analysing different attributes of the data and interpretations we reflect on the main controls on uncertainty. A group of ten expert modellers at the British Geological Survey were asked to interpret an 11.4 km long cross-section from south-east Glasgow, UK. The data provided consisted of map and borehole data of the superficial deposits and shallow bedrock. Each modeller had a unique set of 11 boreholes removed from their dataset, to which their interpretations of the top of the bedrock were compared. This methodology allowed quantification of how far from the 'correct answer' each interpretation is at 11 points along each interpreted cross-section line; through comparison of the interpreted and actual bedrock elevations in the boreholes. This resulted in the collection of 110 measurements of the error to use in further analysis. To determine the potential control on uncertainty various attributes relating to the modeller, the interpretation and the data were recorded. Modellers were asked to fill out a questionnaire asking for information; such as how much 3D modelling experience they had, and how long it took them to complete the interpretation. They were also asked to record their confidence in their interpretations graphically, in the form of a confidence level drawn onto the cross-section. Initial analysis showed the majority of the experts' interpreted bedrock elevations within 5 metres of those recorded in the withheld boreholes. Their distribution is peaked and symmetrical about a mean of zero, indicating that there was no tendency for the experts to either under or over estimate the elevation of the bedrock. More complex analysis was completed in the form of linear mixed effects modelling. The modelling was used to determine if there were any correlations between the error and any other parameter recorded in the questionnaire, section or the initial dataset. This has resulted in the determination of both data based and interpreter based controls on uncertainty, adding insight into how uncertainty can be predicted, as well as how interpretation workflows can be improved. Our results will inform further experiments across a wide variety of geological situations to build understanding and best practice workflows for cross-section interpretation to reduce uncertainty.

Simulation of water-surface elevations for a hypothetical 100-year peak flow in Birch Creek at the Idaho National Engineering and Environmental Laboratory, Idaho

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

Berenbrock, C.; Kjelstrom, L.C.

1997-10-01

Delineation of areas at the Idaho National Engineering and Environmental Laboratory that would be inundated by a 100-year peak flow in Birch Creek is needed by the US Department of Energy to fulfill flood-plain regulatory requirements. Birch Creek flows southward about 40 miles through an alluvium-filled valley onto the northern part of the Idaho National Engineering and Environmental laboratory site on the eastern Snake River Plain. The lower 10-mile reach of Birch Creek that ends in Birch Creek Playa near several Idaho National Engineering and Environmental Laboratory facilities is of particular concern. Twenty-six channel cross sections were surveyed to developmore » and apply a hydraulic model to simulate water-surface elevations for a hypothetical 100-year peak flow in Birch Creek. Model simulation of the 100-year peak flow (700 cubic feet per second) in reaches upstream from State Highway 22 indicated that flow was confined within channels even when all flow was routed to one channel. Where the highway crosses Birch Creek, about 315 cubic feet per second of water was estimated to move downstream--115 cubic feet per second through a culvert and 200 cubic feet per second over the highway. Simulated water-surface elevation at this crossing was 0.8 foot higher than the elevation of the highway. The remaining 385 cubic feet per second flowed southwestward in a trench along the north side of the highway. Flow also was simulated with the culvert removed. The exact location of flood boundaries on Birch Creek could not be determined because of the highly braided channel and the many anthropogenic features (such as the trench, highway, and diversion channels) in the study area that affect flood hydraulics and flow. Because flood boundaries could not be located exactly, only a generalized flood-prone map was developed.« less

Interwell coupling effect in Si/SiGe quantum wells grown by ultra high vacuum chemical vapor deposition

PubMed Central

Wang, Rui; Lu, Fen; Fan, Wei Jun; Liu, Chong Yang; Loh, Ter-Hoe; Nguyen, Hoai Son; Narayanan, Balasubramanian

2007-01-01

Si/Si0.66Ge0.34coupled quantum well (CQW) structures with different barrier thickness of 40, 4 and 2 nm were grown on Si substrates using an ultra high vacuum chemical vapor deposition (UHV-CVD) system. The samples were characterized using high resolution x-ray diffraction (HRXRD), cross-sectional transmission electron microscopy (XTEM) and photoluminescence (PL) spectroscopy. Blue shift in PL peak energy due to interwell coupling was observed in the CQWs following increase in the Si barrier thickness. The Si/SiGe heterostructure growth process and theoretical band structure model was validated by comparing the energy of the no-phonon peak calculated by the 6 + 2-bandk·pmethod with experimental PL data. Close agreement between theoretical calculations and experimental data was obtained.

Monte Carlo simulation of energy deposition by low-energy electrons in molecular hydrogen

NASA Technical Reports Server (NTRS)

Heaps, M. G.; Furman, D. R.; Green, A. E. S.

1975-01-01

A set of detailed atomic cross sections has been used to obtain the spatial deposition of energy by 1-20-eV electrons in molecular hydrogen by a Monte Carlo simulation of the actual trajectories. The energy deposition curve (energy per distance traversed) is quite peaked in the forward direction about the entry point for electrons with energies above the threshold of the electronic states, but the peak decreases and broadens noticeably as the electron energy decreases below 10 eV (threshold for the lowest excitable electronic state of H2). The curve also assumes a very symmetrical shape for energies below 10 eV, indicating the increasing importance of elastic collisions in determining the shape of the curve, although not the mode of energy deposition.

Investigation of discrete states and quasidiscrete structures observed in 150Sm and 152Sm using the ( p,tγ) reaction

DOE PAGES

Peter, Humby; Simon, Anna; Beausang, C. W.; ...

2016-01-01

New levels and γ-ray transitions were identified in 150,152Sm utilizing the (p,t) reaction and particle-γ coincidence data. A large, peak-like structure observed between 2.3–3.0 MeV in excitation energy in the triton energy spectra was also investigated. The orbital angular-momentum transfer was probed by comparing the experimental angular distributions of the outgoing tritons to calculated distorted wave Born approximation curves. The angular distributions of the outgoing tritons populating the peak-like structure are remarkably similar in the two reactions and are significantly different from the angular distributions associated with the nearby continuum region. Relative partial cross sections for the observed levels, anglemore » averaged between 34 and 58 degrees, were measured. In 150Sm, 39(4)% of the strength of the peak-like structure could be accounted for by the observed discrete states. This compares with a value of 93(15)% for 152Sm« less

Investigation of discrete states and quasidiscrete structures observed in 150Sm and 152Sm using the ( p,tγ) reaction

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

Peter, Humby; Simon, Anna; Beausang, C. W.

New levels and γ-ray transitions were identified in 150,152Sm utilizing the (p,t) reaction and particle-γ coincidence data. A large, peak-like structure observed between 2.3–3.0 MeV in excitation energy in the triton energy spectra was also investigated. The orbital angular-momentum transfer was probed by comparing the experimental angular distributions of the outgoing tritons to calculated distorted wave Born approximation curves. The angular distributions of the outgoing tritons populating the peak-like structure are remarkably similar in the two reactions and are significantly different from the angular distributions associated with the nearby continuum region. Relative partial cross sections for the observed levels, anglemore » averaged between 34 and 58 degrees, were measured. In 150Sm, 39(4)% of the strength of the peak-like structure could be accounted for by the observed discrete states. This compares with a value of 93(15)% for 152Sm« less

Regional Curves for Bankfull Channel Characteristics in the Appalachian Plateaus, West Virginia

USGS Publications Warehouse

Messinger, Terence

2009-01-01

Streams in the Appalachian Plateaus Physiographic Province in West Virginia were classified as a single region on the basis of bankfull characteristics. Regression lines for annual peak flow and drainage area measured at streamgages in the study area at recurrence intervals between 1.2 and 1.7 years fell within the 99-percent confidence interval of the regression line for bankfull flow. Channel characteristics were intermediate among those from surrounding states and regions where comparable studies have been done. The stream reaches that were surveyed were selected for apparent stability, and to represent gradients of drainage area, elevation, and mean annual precipitation. Profiles of high-water marks left by bankfull and near-bankfull peaks were surveyed, either as part of slope-area flow measurements at ungaged reaches, or to transfer known flow information to cross sections for gaged reaches. The slope-area measurements made it possible to include ungaged sites in the study, but still relate bankfull dimensions to peak flow and frequency.

Model study of greenline dayglow emission under geomagnetic storm conditions.

NASA Astrophysics Data System (ADS)

Singh, V.; Bag, T.; Sunil Krishna, M. V.

2016-12-01

A comprehensive model is developed to study the influences of geomagnetic storms on greenline (557.7 nm) dayglow emission during the solar active and solar quiet conditions in thermosphere. This study is based on a photochemical model which is developed using the latest reaction rate coefficients, quantum yields and collisional cross-sections obtained from the experimental observations and empirical models. This study is for a low latitude station Tirunelveli (8.7N,77.8E), India. The volume emission rate (VER) has been calculated using the densities and temperature from NRLMSISE-00 and IRI-2012 models. The modeled VER shows a positive correlation with the Dst index, and a negative correlation with the number densities of O, O2, and N2. The VER calculated at the peak emission altitude shows depletion during the main phase of the storm. The peak emission altitude doesn't show any appreciable variation during storm period. On the other hand, the peak emission altitude shows an upward movement with the increase in F10.7 solar index.

Spectrally edited 2D 13Csbnd 13C NMR spectra without diagonal ridge for characterizing 13C-enriched low-temperature carbon materials

NASA Astrophysics Data System (ADS)

Johnson, Robert L.; Anderson, Jason M.; Shanks, Brent H.; Fang, Xiaowen; Hong, Mei; Schmidt-Rohr, Klaus

2013-09-01

Two robust combinations of spectral editing techniques with 2D 13Csbnd 13C NMR have been developed for characterizing the aromatic components of 13C-enriched low-temperature carbon materials. One method (exchange with protonated and nonprotonated spectral editing, EXPANSE) selects cross peaks of protonated and nearby nonprotonated carbons, while the other technique, dipolar-dephased double-quantum/single-quantum (DQ/SQ) NMR, selects signals of bonded nonprotonated carbons. Both spectra are free of a diagonal ridge, which has many advantages: Cross peaks on the diagonal or of small intensity can be detected, and residual spinning sidebands or truncation artifacts associated with the diagonal ridge are avoided. In the DQ/SQ experiment, dipolar dephasing of the double-quantum coherence removes protonated-carbon signals; this approach also eliminates the need for high-power proton decoupling. The initial magnetization is generated with minimal fluctuation by combining direct polarization, cross polarization, and equilibration by 13C spin diffusion. The dipolar dephased DQ/SQ spectrum shows signals from all linkages between aromatic rings, including a distinctive peak from polycondensed aromatics. In EXPANSE NMR, signals of protonated carbons are selected in the first spectral dimension by short cross polarization combined with dipolar dephasing difference. This removes ambiguities of peak assignment to overlapping signals of nonprotonated and protonated aromatic carbons, e.g. near 125 ppm. Spin diffusion is enhanced by dipolar-assisted rotational resonance. Before detection, Csbnd H dipolar dephasing by gated decoupling is applied, which selects signals of nonprotonated carbons. Thus, only cross peaks due to magnetization originating from protonated C and ending on nearby nonprotonated C are retained. Combined with the chemical shifts deduced from the cross-peak position, this double spectral editing defines the bonding environment of aromatic, COO, and Cdbnd O carbons, which is particularly useful for identifying furan and arene rings. The Cdbnd O carbons, whose chemical shifts vary strongly (between 212 and 165 ppm) and systematically depend on their two bonding partners, show particularly informative cross peaks, given that one bonding partner is defined by the other frequency coordinate of the cross peak. The new techniques and the information content of the resulting spectra are validated on sulfuric-acid treated low-temperature carbon materials and on products of the Maillard reaction. The crucial need for spectral editing for correct peak assignment is demonstrated in an example.

A new fold-cross metal mesh filter for suppressing side lobe leakage in terahertz region

NASA Astrophysics Data System (ADS)

Lu, Changgui; Qi, Zhengqing; Guo, Wengao; Cui, Yiping

2018-04-01

In this paper we propose a new type of fold-cross metal mesh band pass filter, which keeps diffraction side lobe far away from the main transmission peak and shows much better side lobe suppression. Both experimental and theoretical studies are made to analyze the mechanism of side lobe. Compared to the traditional cross filter, the fold-cross filter has a much lower side lobe with almost the same central frequency, bandwidth and highest transmission about 98%. Using the photolithography and electroplating techniques, we experimentally extend the distance between the main peak and diffraction side lobe to larger than 1 THz for the fold-cross filter, which is two times larger than the cross filter while maintaining the main peak transmissions of 89% at 1.25 THz for the two structures. This type of single layer substrate-free fold-cross metal structure shows better design flexibility and structure reliability with the introduction of fold arms for metal mesh band pass filters.

Reconstructing the Santa Tecla flash flood in the Ondara River (Ebro Basin, NE Spain)

NASA Astrophysics Data System (ADS)

Balasch, J. C.; Tuset, J.; Ramos, M. C.; Martínez-Casasnovas, J. A.

2009-09-01

The Santa Tecla flood may be considered the most catastrophic rainfall event in the modern history of Catalonia (NE Iberian Peninsula), and one of the most important in the Western Mediterranean Basin. This event took place during the night between 22nd and 23rd September 1874, in which torrential convective rainfalls generated significant flash floods in most of the small streams in the southern half of Catalonia (i.e. Ondara, Corb, Francolí and Siurana catchments). More than 570 people died, 150 of which in the town of Tàrrega, by the Ondara River. Despite being one of the last huge floods of the pre-instrumental era and, consequently, without any precipitation or flow data, the event was reconstructed both hydraulically and hydrologically for the Ondara River at Tàrrega (150 km2). Thus, the maximum water level and the temporal evolution of the flood were obtained, respectively, from several epigraphic limnimarks found in Tàrrega and from the event description recorded in historical documents. Additionally, the information from local archaeological sites allowed the reconstruction of the fluvial section at Tàrrega at the end of the 19th century. Finally, some old cellars flooded during the event provided information about sediment concentration at the peak flow. The methodology put into practice for the event reconstruction had two stages. The first stage was the hydraulic modelling, which estimated the peak flow. The input data used were the maximum water level given by the limnimetric marks, a digital terrain model of the river bed shape, and the stream and floodplain roughness and channel slope (which were considered similar to the present ones, according to archaeological data). The hydraulic model used was the unidimensional HEC-RAS (USACE), applied in several cross sections of the Ondara River at Tàrrega. The second stage was the hydrological modelling. The objective of this stage was to derive the event hyetograph from the above calculated peak flow and the hydrologic response of the basin. This hydrologic behaviour, that is the relation between the hyetograph and the hydrograph, was estimated taking into account rainfall duration (6-8 hours according to historical documents), basin characteristics, soil type, soil land use and cover and the antecedent soil moisture, using SCS Curve Number method. After that, a transfer Synthetic Unitary Hydrograph function and a wave propagation method (Muskingum) were applied to describe the discharge evolution and the water routing into the stream channel. The software used in this stage was the HEC-HMS (USACE). The results of the hydraulic simulation at the Sant Agustí street cross section were the following: a) a maximum water depth of 6.16 m above the original river bed, b) a mean water velocity of about 2 m•s-1, c) a peak flow of 996 m3•s-1 (increased by 480 m3•s-1 from the Cercavins River downstream Tàrrega), and d) a specific peak discharge of the event of 6.6 m3•s-1•km-2, which exceeds the values of the 500-year return period floods compiled from the Ebro drainage basin systematic database. From the information obtained in the flooded cellars, the sediment concentration during the peak flow was estimated in 11.2% (in volume), characteristic of a hyperconcentrated flow. The water level reached in the abovepresented cross section is partly explained by the recently discovered Sant Agustí Bridge, buried until now in the river bed. The results of the hydrologic modelling were: a) a surface runoff total volume of 12 hm3, b) a runoff coefficient of about 35.5%, c) a lagtime of 2.5-3 hours, and d) if the previous soil humidity for the Curve Number method was low (situation I), a total rainfall of 225 mm with a peak intensity higher than 100 mm•h-1 is needed; if the previous soil humidity for the Curve Number method was medium (situation II), a total rainfall of 156 mm with a peak intensity of about 70 mm•h-1 occurs. Rainfall values for medium previous moisture condition (II) represent a 1000-year return period according to the regional systematic data.

Returners Exhibit Greater Jumping Performance Improvements During a Peaking Phase Compared With New Players on a Volleyball Team.

PubMed

Bazyler, Caleb D; Mizuguchi, Satoshi; Kavanaugh, Ashley A; McMahon, John J; Comfort, Paul; Stone, Michael H

2018-06-21

To determine if jumping-performance changes during a peaking phase differed among returners and new players on a female collegiate volleyball team and to determine which variables best explained the variation in performance changes. Fourteen volleyball players were divided into 2 groups-returners (n = 7) and new players (n = 7)-who completed a 5-wk peaking phase prior to conference championships. Players were tested at baseline before the preseason on measures of the vastus lateralis cross-sectional area using ultrasonography, estimated back-squat 1-repetition maximum, countermovement jump height (JH), and relative peak power on a force platform. Jumping performance, rating of perceived exertion training load, and sets played were recorded weekly during the peaking phase. There were moderate to very large (P < .01, Glass Δ = 1.74) and trivial to very large (P = .07, Δ = 1.09) differences in JH and relative peak power changes in favor of returners over new players, respectively, during the peaking phase. Irrespective of group, 7 of 14 players achieved peak JH 2 wk after the initial overreach. The number of sets played (r = .78, P < .01) and the athlete's preseason relative 1-repetition maximum (r = .54, P = .05) were the strongest correlates of JH changes during the peaking phase. Returners achieved greater improvements in jumping performance during the peaking phase compared with new players, which may be explained by the returners' greater relative maximal strength, time spent competing, and training experience. Thus, volleyball and strength coaches should consider these factors when prescribing training during a peaking phase to ensure their players are prepared for important competitions.

Anomalous anisotropies of fission fragments in near- and sub-barrier fusion-fussion reactions

NASA Astrophysics Data System (ADS)

Huanqiao, Zhang; Zuhua, Liu; Jincheng, Xu; Jun, Lu; Ming, Ruan; Kan, Xu

1992-03-01

Fission cross sections and angular distributions have been measured for the reactions of 16O + 232Th and238U, and19F + 208Pb and232Th at near- and sub-barrier energies. The fission excitation functions are rather well reproduced on the basis of Wong model or coupled channels theory. However, the models which reproduce the sub-barrier fusion cross sections fail to account for the experimental anisotropies of fission fragments. It is found that the observed anisotropies are much larger than expected. For the first time it has been observed that the anisotropies as a function of the center-of-mass energy show a peak centered near 4.5 MeV below the fusion barrier for several reaction systems. The present approaches fail to explain these anomalies. For 19F + 208Pb systems, our results confirm the prediction of an approximately constant value for the mean square spin of the compound nucleus produced in far sub-barrier fusion reaction.

Role of ω -meson exchange in scaling of the γ p →π0p process from a Regge-type model with resonances

NASA Astrophysics Data System (ADS)

Kong, Kook-Jin; Choi, Tae Keun; Yu, Byung-Geel

2016-08-01

The scaling of photoproduction γ p →π0p is investigated in the Reggeized model with N* and Δ resonances included to describe resonance peaks up to photon energy Eγ=3 GeV . Given the t -channel exchanges ρ (770 ) +ω (780 ) +b1(1235 ) +h1(1170 ) Reggeized for the background contribution, the resonances of the Breit-Wigner form are introduced to agree with cross sections for total, differential, and beam asymmetry in the low energy region. The scaled differential cross sections s7d σ /d t are reproduced to agree with the recent JLab data, revealing the production mechanism of the big bump structure around W ≈2.2 GeV by the deep-dip pattern of the ω exchange that originates from the zeros of the trajectory αω(t ) =0 in the canonical phase, 1/2 (-1 +e-i π αω(t )) .

Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study.

PubMed

Fan, Z Joyce; Harris-Adamson, Carisa; Gerr, Fred; Eisen, Ellen A; Hegmann, Kurt T; Bao, Stephen; Silverstein, Barbara; Evanoff, Bradley; Dale, Ann Marie; Thiese, Matthew S; Garg, Arun; Kapellusch, Jay; Burt, Susan; Merlino, Linda; Rempel, David

2015-05-01

Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS). Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression. Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration. In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors. © 2015 Wiley Periodicals, Inc.

Target scattering characteristics for OAM-based radar

NASA Astrophysics Data System (ADS)

Liu, Kang; Gao, Yue; Li, Xiang; Cheng, Yongqiang

2018-02-01

The target scattering characteristics are crucial for radar systems. However, there is very little study conducted for the recently developed orbital angular momentum (OAM) based radar system. To illustrate the role of OAM-based radar cross section (ORCS), conventional radar equation is modified by taking characteristics of the OAM waves into account. Subsequently, the ORCS is defined in analogy to classical radar cross section (RCS). The unique features of the incident OAM-carrying field are analyzed. The scattered field is derived, and the analytical expressions of ORCSs for metal plate and cylinder targets are obtained. Furthermore, the ORCS and RCS are compared to illustrate the influences of OAM mode number, target size and signal frequency on the ORCS. Analytical studies demonstrate that the mirror-reflection phenomenon disappears and peak values of ORCS are in the non-specular direction. Finally, the ORCS features are summarized to show its advantages in radar target detection. This work can provide theoretical guidance to the design of OAM-based radar as well as the target detection and identification applications.

Analysis of MCNP simulated gamma spectra of CdTe detectors for boron neutron capture therapy.

PubMed

Winkler, Alexander; Koivunoro, Hanna; Savolainen, Sauli

2017-06-01

The next step in the boron neutron capture therapy (BNCT) is the real time imaging of the boron concentration in healthy and tumor tissue. Monte Carlo simulations are employed to predict the detector response required to realize single-photon emission computed tomography in BNCT, but have failed to correctly resemble measured data for cadmium telluride detectors. In this study we have tested the gamma production cross-section data tables of commonly used libraries in the Monte Carlo code MCNP in comparison to measurements. The cross section data table TENDL-2008-ACE is reproducing measured data best, whilst the commonly used ENDL92 and other studied libraries do not include correct tables for the gamma production from the cadmium neutron capture reaction that is occurring inside the detector. Furthermore, we have discussed the size of the annihilation peaks of spectra obtained by cadmium telluride and germanium detectors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fluorescence investigation of Ho3+ in Yb3+ sensitized mixed-alkali bismuth gallate glasses.

PubMed

Lin, H; Zhang, Y Y; Pun, E Y B

2008-12-15

Efficient 2.0 microm infrared and visible upconversion emissions have been observed in Ho3+/Yb3+ co-doped mixed-alkali bismuth gallate (LKBBG) glasses having a maximum-phonon energy of 673 cm(-1). The Judd-Ofelt parameters Omega2, Omega4 and Omega6 of Ho3+ indicate that there is a high asymmetry and strong covalent environment in LKBBG glasses. The large absorption and emission cross-sections of Yb3+ confirm that it is a suitable sensitizer for capturing and transferring pump energy to Ho3+. The emission cross-section profile for the 5I7-->5I8 transition is derived using the reciprocity method and the peak value is 5.54 x 10(-21)cm2, which is much larger than the value in fluorozircoaluminate glasses. LKBBG glasses exhibit low maximum-phonon energy and large refractive index, and it is possible to achieve an effective 1.66 microm U-band emission of Ho3+ under 900 nm laser radiation.

Energy Scan of the e^{+}e^{-}→h_{b}(nP)π^{+}π^{-} (n=1, 2) Cross Sections and Evidence for ϒ(11020) Decays into Charged Bottomoniumlike States.

PubMed

Mizuk, R; Bondar, A; Adachi, I; Aihara, H; Asner, D M; Atmacan, H; Aulchenko, V; Aushev, T; Ayad, R; Badhrees, I; Bakich, A M; Barberio, E; Behera, P; Bhardwaj, V; Bhuyan, B; Biswal, J; Bobrov, A; Bonvicini, G; Bozek, A; Bračko, M; Browder, T E; Červenkov, D; Chekelian, V; Chen, A; Cheon, B G; Chilikin, K; Chistov, R; Chobanova, V; Choi, S-K; Choi, Y; Cinabro, D; Dalseno, J; Danilov, M; Dash, N; Doležal, Z; Drutskoy, A; Eidelman, S; Epifanov, D; Ferber, T; Fulsom, B G; Gaur, V; Garmash, A; Gillard, R; Goh, Y M; Goldenzweig, P; Golob, B; Greenwald, D; Hara, T; Hayasaka, K; Hayashii, H; Hou, W-S; Hsu, C-L; Inami, K; Inguglia, G; Ishikawa, A; Iwasaki, Y; Jaegle, I; Julius, T; Kang, K H; Katrenko, P; Kim, D Y; Kim, H J; Kim, J B; Kim, K T; Kim, M J; Kim, S H; Kim, Y J; Kinoshita, K; Kodyš, P; Korpar, S; Kotchetkov, D; Krokovny, P; Kuhr, T; Kuzmin, A; Kwon, Y-J; Lange, J S; Li, C H; Li, H; Li, L; Li Gioi, L; Libby, J; Liventsev, D; Lubej, M; Luo, T; Masuda, M; Matsuda, T; Matvienko, D; Miyabayashi, K; Miyata, H; Mohanty, G B; Moll, A; Nakano, E; Nakao, M; Nanut, T; Nath, K J; Negishi, K; Niiyama, M; Nisar, N K; Nishida, S; Ogawa, S; Okuno, S; Olsen, S L; Onuki, Y; Pakhlov, P; Pakhlova, G; Pal, B; Park, C W; Park, H; Paul, S; Pedlar, T K; Pestotnik, R; Petrič, M; Piilonen, L E; Pulvermacher, C; Ritter, M; Sakai, Y; Sandilya, S; Sanuki, T; Savinov, V; Schlüter, T; Schneider, O; Schnell, G; Schwanda, C; Seino, Y; Semmler, D; Senyo, K; Seon, O; Sevior, M E; Shebalin, V; Shibata, T-A; Shiu, J-G; Shwartz, B; Simon, F; Solovieva, E; Starič, M; Stypula, J; Sumiyoshi, T; Takizawa, M; Tamponi, U; Tanida, K; Teramoto, Y; Tikhomirov, I; Trabelsi, K; Uchida, M; Uglov, T; Unno, Y; Uno, S; Urquijo, P; Usov, Y; Van Hulse, C; Varner, G; Vorobyev, V; Wang, C H; Wang, M-Z; Wang, P; Wang, X L; Watanabe, Y; Williams, K M; Won, E; Yamaoka, J; Yamashita, Y; Yelton, J; Yuan, C Z; Zhang, Z P; Zhilich, V; Zhukova, V; Zhulanov, V; Zupanc, A

2016-09-30

Using data collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider, we measure the energy dependence of the e^{+}e^{-}→h_{b}(nP)π^{+}π^{-} (n=1, 2) cross sections from thresholds up to 11.02 GeV. We find clear ϒ(10860) and ϒ(11020) peaks with little or no continuum contribution. We study the resonant substructure of the ϒ(11020)→h_{b}(nP)π^{+}π^{-} transitions and find evidence that they proceed entirely via the intermediate isovector states Z_{b}(10610) and Z_{b}(10650). The relative fraction of these states is loosely constrained by the current data: The hypothesis that only Z_{b}(10610) is produced is excluded at the level of 3.3 standard deviations, while the hypothesis that only Z_{b}(10650) is produced is not excluded at a significant level.

The Iron Project & Iron Opacity Project: Updates on Photoionization, Electron-Ion Recombination of Fe XVII and Ca XV

NASA Astrophysics Data System (ADS)

Eissner, W.; Nahar, S.; Pradhan, A.; Hala, H.; Zhao, L.; Bailey, J.

2016-05-01

We have carried out converged close coupling (CCC) calculations for photoionization of Ne-like Fe XVII and demonstrate orders-of-magnitude enhancements in cross section due to successive core excitations. Convergence criteria are: (i) inclusion of sufficient number of residual ion Fe XVIII core states and (ii) high-resolution of myriad autoionizing resonances. We discuss verification of the conventional oscillator strength sum-rule in limited energy regions for bound-free plasma opacity. We will also report preliminary results from a larger R-matrix calculations of photoionization cross sections and electron-ion recombination rates of Ca XV where Rydberg series of resonances are included for core excitations to 28 states of n=2,3 complexes in contrast to previous 7 states of n=2 complex. The new results show existence of high-peak resonances of n=3 complex and enhanced background in high energy photoionization and a corresponding enhancement in the recombination in the high temperature region. Partial support: NSF, DOE, Ohio Supercomputer Center.

The influence of velocity-specific resistance training on the in vivo torque-velocity relationship and the cross-sectional area of quadriceps femoris.

PubMed

Petersen, S R; Bagnall, K M; Wenger, H A; Reid, D C; Castor, W R; Quinney, H A

1989-01-01

This work was supported by Sport Canada end Hydra-Fitness Industries. In order to investigate the effects of velocity-specific resistance training, 30 healthy, male varsity athletes were assigned to either high (HVR) or low (LVR) velocity training or control (CG) groups. Subjects completed two 20-sec sets of maximal exercise at each of six hydraulic resistance stations for the lower limb. Resistances were adjusted as necessary to maintain consistent average angular velocities of approximately 1.05 and 3.14 rad/sec for the LVR and HVR groups, respectively. Subjects trained on alternate days for 6 weeks, completing either two (weeks 1 and 2) or three (weeks 3-6) circuits of the six stations each session. Peak knee extension torques were improved (p < 0.05) for the LVR group at all of seven angular velocities tested between 1.05 and 4.19 rad/sec. Improvements (p < 0.05) were also observed for the HVR group, but only at angular velocities of 2.62, 3.14, 3.66, and 4.19 rad/sec. Cross-sectional area of the quadriceps femoris muscle group obtained from serial computer tomography (CT) scans was increased (p < 0.05) for both training groups. No significant changes in either strength or cross-sectional area were observed for control subjects. These results indicate that while both of the training programs resulted in increased cross-sectional area of the knee extensors, the observed changes in strength performance are likely due to other factors which may be mediated by the different training velocities. J Orthop Sports Phys Ther 1989;10(11):456-462.

Ozone Observations by the Gas and Aerosol Measurement Sensor during SOLVE II

NASA Technical Reports Server (NTRS)

Pitts, M. C.; Thomason, L. W.; Zawodny, J. M.; Wenny, B. N.; Livingston, J. M.; Russell, P. B.; Yee, J.-H.; Swartz, W. H.; Shetter, R. E.

2006-01-01

The Gas and Aerosol Measurement Sensor (GAMS) was deployed aboard the NASA DC-8 aircraft during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II). GAMS acquired line-of-sight (LOS) direct solar irradiance spectra during the sunlit portions of ten science flights of the DC-8 between 12 January and 4 February 2003. Differential line-of-sight (DLOS) optical depth spectra are produced from the GAMS raw solar irradiance spectra. Then, DLOS ozone number densities are retrieved from the GAMS spectra using a multiple linear regression spectral fitting technique. Both the DLOS optical depth spectra and retrieved ozone data are compared with coincident measurements from two other solar instruments aboard the DC-8 platform to demonstrate the robustness and stability of the GAMS data. The GAMS ozone measurements are then utilized to evaluate the quality of the Wulf band ozone cross sections, a critical component of the SAGE III aerosol, water vapor, and temperature/pressure retrievals. Results suggest the ozone cross section compilation of Shettle and Anderson currently used operationally in SAGE III data processing may be in error by as much as 10-20% in theWulf bands, and their lack of reported temperature dependence is a significant deficiency. A second, more recent, cross section database compiled for the SCIAMACHY satellite mission appears to be of much better quality in the Wulf bands, but still may have errors as large as 5% near the Wulf band absorption peaks, which is slightly larger than their stated uncertainty. Additional laboratory measurements of the Wulf band cross sections should be pursued to further reduce their uncertainty and better quantify their temperature dependence.

CFTR Genotype and Maximal Exercise Capacity in Cystic Fibrosis: A Cross-sectional Study.

PubMed

Radtke, Thomas; Hebestreit, Helge; Gallati, Sabina; Schneiderman, Jane E; Braun, Julia; Stevens, Daniel; Hulzebos, Erik Hj; Takken, Tim; Boas, Steven R; Urquhart, Don S; Lands, Larry C; Tejero, Sergio; Sovtic, Aleksandar; Dwyer, Tiffany; Petrovic, Milos; Harris, Ryan A; Karila, Chantal; Savi, Daniela; Usemann, Jakob; Mei-Zahav, Meir; Hatziagorou, Elpis; Ratjen, Felix; Kriemler, Susi

2018-02-01

Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in human skeletal muscle cells. Variations of CFTR dysfunction among patients with cystic fibrosis may be an important determinant of maximal exercise capacity in cystic fibrosis. Previous studies on the relationship between CFTR genotype and maximal exercise capacity are scarce and contradictory. This study was designed to explore factors influencing maximal exercise capacity, expressed as peak oxygen uptake (V.O2peak), with a specific focus on CFTR genotype in children and adults with cystic fibrosis. In an international, multicenter, cross-sectional study, we collected data on CFTR genotype and cardiopulmonary exercise tests in patients with cystic fibrosis who were ages 8 years and older. CFTR mutations were classified into functional classes I–V. The final analysis included 726 patients (45% females; age range, 8–61 yr; forced expiratory volume in 1 s, 16 to 123% predicted) from 17 cystic fibrosis centers in North America, Europe, Australia, and Asia, all of whom had both valid maximal cardiopulmonary exercise tests and complete CFTR genotype data. Overall, patients exhibited exercise intolerance (V.O2peak, 77.3 ± 19.1% predicted), but values were comparable among different CFTR classes. We did not detect an association between CFTR genotype functional classes I–III and either V.O2peak (percent predicted) (adjusted β = −0.95; 95% CI, −4.18 to 2.29; P = 0.57) or maximum work rate (Wattmax) (adjusted β = −1.38; 95% CI, −5.04 to 2.27; P = 0.46) compared with classes IV–V. Those with at least one copy of a F508del-CFTR mutation and one copy of a class V mutation had a significantly lower V.O2peak (β = −8.24%; 95% CI, −14.53 to −2.99; P = 0.003) and lower Wattmax (adjusted β = −7.59%; 95% CI, −14.21 to −0.95; P = 0.025) than those with two copies of a class II mutation. On the basis of linear regression analysis adjusted for relevant confounders, lung function and body mass index were associated with V.O2peak. CFTR functional genotype class was not associated with maximal exercise capacity in patients with cystic fibrosis overall, but those with at least one copy of a F508del-CFTR mutation and a single class V mutation had lower maximal exercise capacity.

Cervical Muscle Strength and Muscle Coactivation During Isometric Contractions in Patients With Migraine: A Cross-Sectional Study.

PubMed

Florencio, Lidiane Lima; de Oliveira, Anamaria Siriani; Carvalho, Gabriela Ferreira; Tolentino, Gabriella de Almeida; Dach, Fabiola; Bigal, Marcelo Eduardo; Fernández-de-las-Peñas, César; Bevilaqua Grossi, Débora

2015-01-01

This cross-sectional study investigated potential differences in cervical musculature in groups of migraine headaches vs. non-headache controls. Differences in cervical muscle strength and antagonist coactivation during maximal isometric voluntary contraction (MIVC) were analyzed between individuals with migraine and non-headache subjects and relationships between force with migraine and neck pain clinical aspects. A customized hand-held dynamometer was used to assess cervical flexion, extension, and bilateral lateral flexion strength in subjects with episodic migraine (n=31), chronic migraine (n = 21) and healthy controls (n = 31). Surface electromyography (EMG) from sternocleidomastoid, anterior scalene, and splenius capitis muscles were recorded during MIVC to evaluate antagonist coactivation. Comparison of main outcomes among groups was conducted with one-way analysis of covariance with the presence of neck pain as covariable. Correlations between peak force and clinical variables were demonstrated by Spearman's coefficient. Chronic migraine subjects exhibited lower cervical extension force (mean diff. from controls: 4.4 N/kg; mean diff from episodic migraine: 3.7 N/kg; P = .006) and spent significantly more time to generate peak force during cervical flexion (mean diff. from controls: 0.5 seconds; P = .025) and left lateral-flexion (mean diff. from controls: 0.4 seconds; mean diff. from episodic migraine: 0.5 seconds; P = .007). Both migraine groups showed significantly higher antagonist muscle coactivity of the splenius capitis muscle (mean diff. from controls: 20%MIVC, P = .03) during cervical flexion relative to healthy controls. Cervical extension peak force was moderately associated with the migraine frequency (rs: -0.30, P = .034), neck pain frequency (rs: -0.26, P = .020), and neck pain intensity (rs: -0.27, P = .012). Patients with chronic migraine exhibit altered muscle performance, took longer to reach peak of force during some cervical movements, and had higher coactivation of the splenius capitis during maximal isometric cervical flexion contraction. Finally, patients with migraine reported the presence of neck and head pain complaints during maximal isometric voluntary cervical contractions. © 2015 American Headache Society.

Tibial Acceleration and Spatiotemporal Mechanics in Distance Runners During Reduced-Body-Weight Conditions.

PubMed

Moran, Matthew F; Rickert, Brendan J; Greer, Beau K

2017-05-01

Treadmills that unload runners via a differential air-pressure (DAP) bladder (eg, AlterG Anti-Gravity Treadmill) are commonly used to reduce effective body weight (BW) in a clinical setting. However, the relationship between the level of unloading and tibial stress is currently unknown. To determine the relationship between tibial impact acceleration and level of BW unloading during running. Cross-sectional. University motion-analysis laboratory. 15 distance runners (9 male, 6 female; 20.4 ± 2.4 y, 60.1 ± 12.6 kg). Peak tibial acceleration and peak-to-peak tibial acceleration were measured via a uniaxial accelerometer attached to the tibia during a 37-min continuous treadmill run that simulated reduced-BW conditions via a DAP bladder. The trial began with a 10-min run at 100% BW followed by nine 3-min stages where BW was systematically reduced from 95% to 60% in 5% increments. There was no significant relationship between level of BW and either peak tibial acceleration or peak-to-peak tibial acceleration (P > .05). Both heart rate and step rate were significantly reduced with each 5% reduction in BW level (P < .01). Although ground-reaction forces are reduced when running in reduced-BW conditions on a DAP treadmill, tibial shock magnitudes are unchanged as an alteration in spatiotemporal running mechanics (eg, reduced step rate) and may nullify the unloading effect.

Validity of trunk extensor and flexor torque measurements using isokinetic dynamometry.

PubMed

Guilhem, Gaël; Giroux, Caroline; Couturier, Antoine; Maffiuletti, Nicola A

2014-12-01

This study aimed to evaluate the validity and test-retest reliability of trunk muscle strength testing performed with a latest-generation isokinetic dynamometer. Eccentric, isometric, and concentric peak torque of the trunk flexor and extensor muscles was measured in 15 healthy subjects. Muscle cross sectional area (CSA) and surface electromyographic (EMG) activity were respectively correlated to peak torque and submaximal isometric torque for erector spinae and rectus abdominis muscles. Reliability of peak torque measurements was determined during test and retest sessions. Significant correlations were consistently observed between muscle CSA and peak torque for all contraction types (r=0.74-0.85; P<0.001) and between EMG activity and submaximal isometric torque (r ⩾ 0.99; P<0.05), for both extensor and flexor muscles. Intraclass correlation coefficients were comprised between 0.87 and 0.95, and standard errors of measurement were lower than 9% for all contraction modes. The mean difference in peak torque between test and retest ranged from -3.7% to 3.7% with no significant mean directional bias. Overall, our findings establish the validity of torque measurements using the tested trunk module. Also considering the excellent test-retest reliability of peak torque measurements, we conclude that this latest-generation isokinetic dynamometer could be used with confidence to evaluate trunk muscle function for clinical or athletic purposes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling of Mechanical Stress Exerted by Cholesterol Crystallization on Atherosclerotic Plaques.

PubMed

Luo, Yuemei; Cui, Dongyao; Yu, Xiaojun; Chen, Si; Liu, Xinyu; Tang, Hongying; Wang, Xianghong; Liu, Linbo

2016-01-01

Plaque rupture is the critical cause of cardiovascular thrombosis, but the detailed mechanisms are not fully understood. Recent studies have found abundant cholesterol crystals in ruptured plaques, and it has been proposed that the rapid expansion of cholesterol crystals in a limited space during crystallization may contribute to plaque rupture. To evaluate the effect of cholesterol crystal growth on atherosclerotic plaques, we modeled the expansion of cholesterol crystals during the crystallization process in the necrotic core and estimated the stress on the thin cap with different arrangements of cholesterol crystals. We developed a two-dimensional finite element method model of atherosclerotic plaques containing expanding cholesterol crystals and investigated the effect of the magnitude and distribution of crystallization on the peak circumferential stress born by the cap. Using micro-optical coherence tomography (μOCT), we extracted the cross-sectional geometric information of cholesterol crystals in human atherosclerotic aorta tissue ex vivo and applied the information to the model. The results demonstrate that (1) the peak circumference stress is proportionally dependent on the cholesterol crystal growth; (2) cholesterol crystals at the cap shoulder impose the highest peak circumference stress; and (3) spatial distributions of cholesterol crystals have a significant impact on the peak circumference stress: evenly distributed cholesterol crystals exert less peak circumferential stress on the cap than concentrated crystals.

Influence of shift work on the physical work capacity of Tunisian nurses: a cross-sectional study in two university hospitals.

PubMed

Merchaoui, Irtyah; Bouzgarrou, Lamia; Mnasri, Ahlem; Mghanem, Mounir; Akrout, Mohamed; Malchaire, Jacques; Chaari, Neila

2017-01-01

This study has been performed to determine the influence of rotating shift work on physical working capacity of Tunisian nurses and to design recommendations to managers so that they implement effective preventive measures. It is a cross-sectional design using a standardized questionnaire and many physical capacity tests on a representative sample of 1181 nurses and nursing assistants from two university hospital centers of the school of Medicine of Monastir located in the Tunisian Sahel. 293 participants have been recruited by stratified random sampling according to gender and departments. Maximum Grip strength, 30s sit-to-stand test, one leg test, Fingertip-to-Floor test, Saltsa test and peak expiratory flow were used to assess physical capacity. Work ability was assessed through the workability index. Mental and physical loads were heavily perceived in shift healthcare workers (p=0.01; p=0.02). The maximum grip force was stronger in rotating shift work nurses (p=0.0001). Regarding to the seniority subgroups in each kind of work schedule, the Body Mass Index was increasing with seniority in both schedules. All the physical tests, were better in less-than-ten-year groups. Peak Flow and grip strength were significantly better in less-than-ten-year seniority in shift work group. There is a need to improve the design of the existing shift systems and to reduce as much as possible shift schedule as well as to avoid shift schedule for over-10-year-seniority nurses.

Observation of pi{sup +}pi{sup -}pi{sup +}pi{sup -} photoproduction in ultraperipheral heavy-ion collisions at sq root(s{sub NN})=200 GeV at the STAR detector

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

Abelev, B. I.; Betts, R. R.; Evdokimov, O.

We present a measurement of pi{sup +}pi{sup -}pi{sup +}pi{sup -} photonuclear production in ultraperipheral Au-Au collisions at sq root(s{sub N{sub N}})=200 GeV from the STAR experiment. The pi{sup +}pi{sup -}pi{sup +}pi{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The pi{sup +}pi{sup -}pi{sup +}pi{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540+-40 MeV/c{sup 2} with a width of 570+-60 MeV/c{sup 2}, in agreement with themore » photoproduction data for the rho{sup 0}(1700). We do not observe a corresponding peak in the pi{sup +}pi{sup -} final state and measure an upper limit for the ratio of the branching fractions of the rho{sup 0}(1700) to pi{sup +}pi{sup -} and pi{sup +}pi{sup -}pi{sup +}pi{sup -} of 2.5% at 90% confidence level. The ratio of rho{sup 0}(1700) and rho{sup 0}(770) coherent production cross sections is measured to be 13.4+-0.8{sub stat.}+-4.4{sub syst.}%.« less

Somatic maturation and the relationship between bone mineral variables and types of sports among adolescents: cross-sectional study.

PubMed

Agostinete, Ricardo Ribeiro; Ito, Igor Hideki; Kemper, Han; Pastre, Carlos Marcelo; Rodrigues-Júnior, Mário Antônio; Luiz-de-Marco, Rafael; Fernandes, Rômulo Araújo

2017-01-01

Peak height velocity (PHV) is an important maturational event during adolescence that affects skeleton size. The objective here was to compare bone variables in adolescents who practiced different types of sports, and to identify whether differences in bone variables attributed to sports practice were dependent on somatic maturation status. Cross-sectional study, São Paulo State University (UNESP). The study was composed of 93 adolescents (12 to 16.5 years old), divided into three groups: no-sport group (n = 42), soccer/basketball group (n = 26) and swimming group (n = 25). Bone mineral density and content were measured using dual-energy x-ray absorptiometry and somatic maturation was estimated through using peak height velocity. Data on training load were provided by the coaches. Adolescents whose PHV occurred at an older age presented higher bone mineral density in their upper limbs (P = 0.018). After adjustments for confounders, such as somatic maturation, the swimmers presented lower values for bone mineral density in their lower limbs, spine and whole body. Only the bone mineral density in the upper limbs was similar between the groups. There was a negative relationship between whole-body bone mineral content and the weekly training hours (β: -1563.967; 95% confidence interval, CI: -2916.484 to -211.450). The differences in bone variables attributed to sport practice occurred independently of maturation, while high training load in situations of hypogravity seemed to be related to lower bone mass in swimmers.

Magnetospheric Multiscale Observations of Electron Vortex Magnetic Hole in the Turbulent Magnetosheath Plasma

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

Huang, S. Y.; Yuan, Z. G.; Wang, D. D.

We report on the observations of an electron vortex magnetic hole corresponding to a new type of coherent structure in the turbulent magnetosheath plasma using the Magnetospheric Multiscale mission data. The magnetic hole is characterized by a magnetic depression, a density peak, a total electron temperature increase (with a parallel temperature decrease but a perpendicular temperature increase), and strong currents carried by the electrons. The current has a dip in the core region and a peak in the outer region of the magnetic hole. The estimated size of the magnetic hole is about 0.23 ρ {sub i} (∼30 ρ {submore » e}) in the quasi-circular cross-section perpendicular to its axis, where ρ {sub i} and ρ {sub e} are respectively the proton and electron gyroradius. There are no clear enhancements seen in high-energy electron fluxes. However, there is an enhancement in the perpendicular electron fluxes at 90° pitch angle inside the magnetic hole, implying that the electrons are trapped within it. The variations of the electron velocity components V {sub em} and V {sub en} suggest that an electron vortex is formed by trapping electrons inside the magnetic hole in the cross-section in the M – N plane. These observations demonstrate the existence of a new type of coherent structures behaving as an electron vortex magnetic hole in turbulent space plasmas as predicted by recent kinetic simulations.« less

Change in the contractile behavior of muscle fibers in subjects with primary muscle dysfunction.

PubMed

Back, Claudio Gregório Nuernberg; Benedini-Elias, Priscila C O; Mattiello, Stela M; Sobreira, Claudia; Martinez, Edson Z; Mattiello-Sverzut, Ana Claudia

2013-01-01

The mechanical and metabolic characteristics of skeletal muscle fibers can interfere with muscle contractile performance in healthy subjects. Few studies have investigated the degree of association between muscle function and muscle fiber morphology in patients with myopathy. A biopsy was obtained from the left biceps brachii muscle of 12 subjects with myopathic disorders. The relative cross-sectional area of type 2 fibers and their subtypes was determined by the ATPase technique. Relative torque (RT) was calculated by dividing isokinetic elbow flexion peak torque (PT) values (90 and 180° s-1) by isometric PT values. Correlations were analyzed using Spearman's coefficient (r). The relative cross-sectional area of type 2b fibers was positively correlated with RT90 (r = 0.71, P = 0.009) and RT180 (r = 0.73, P = 0.007). The relative cross-sectional area of type 2a fibers showed a moderate and negative correlation with RT180 (r = -0.62, P = 0.03) and a low correlation with RT90 (r = -0.57, P = 0.05). In contrast to healthy subjects, patients with myopathy presented changes in the contractile behavior of type 2a fibers and compensatory adaptations in type 2b fibers. The results suggest that RT in combination with morphometric parameters provides data regarding muscle function in patients with myopathic disorders and can contribute to the establishment of therapeutic exercises.

Measurements of Positronium Formation Cross Sections for Positron-Kr, Xe Scattering

NASA Astrophysics Data System (ADS)

Kauppila, W. E.; Kwan, C. K.; Li, H.; Stein, T. S.; Zhou, S.

1997-04-01

Our experimental approach(S. Zhou et al., Phys. Rev. Lett. 73, 236 (1994).) for measuring Ps formation cross sections (Q_Ps) involves passing a variable energy positron beam through a gas scattering cell and detecting the 511 keV annihilation gamma rays resulting from the decay of para-Ps and from the interaction of ortho-Ps with the walls of the scattering cell. It is found that the Q_Ps curves for both Kr and Xe rise rapidly from their formation threshold energies of 7.2 and 5.3 eV, reach maxima within about 10 eV of their thresholds and then decrease to become rather small (less than 10% of the peak heights) above 100 eV. At the maxima Q_Ps accounts for more than 50% of the total scattering cross sections. There is some evidence of possible small scale structure in the Q_Ps curves between 10 and 100 eV. The present results are consistent with the prior measurements of Diana et al.( L.M. Diana et al., in "Atomic Physics with Positrons", edited by J.W. Humberston and E.A.G. Armour (Plenum, New York and London, 1987), p. 55; and in "Positron Annihilation", edited by L. Dorikens-Vanpraet et al. (World Scientific, Singapore, 1989), p. 311.) from near threshold to 70 eV for Kr and from 15 to 100 eV for Xe.

Measurement of νμ charged-current single π0 production on hydrocarbon in the few-GeV region using MINERvA

NASA Astrophysics Data System (ADS)

Altinok, O.; Le, T.; Aliaga, L.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Caceres Vera, G. F. R.; Cai, T.; Carneiro, M. F.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Gran, R.; Han, J. Y.; Harris, D. A.; Kleykamp, J.; Kordosky, M.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; Martinez Caicedo, D. A.; McFarland, K. S.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman, Paolone, V.; Patrick, C. E.; Perdue, G. N.; Ramirez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Sobczyk, J. T.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Valencia, E.; Wolcott, J.; Yaeggy, B.

2017-10-01

The semiexclusive channel νμ+CH →μ-π0+nucleon(s ) is analyzed using MINERvA exposed to the low-energy NuMI νμ beam with spectral peak at Eν≃3 GeV . Differential cross sections for muon momentum and production angle, π0 kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section σ (Eν) is obtained over the range 1.5 GeV ≤Eν<20 GeV . Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for charged-current π+(π0) production by νμ(ν¯μ) neutrinos. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for Q2 that may reflect shortfalls in modeling of interactions on carbon. For π0 kinematic distributions, however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as π0 mesons, the p π0 invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the p π0 system are measured in the region of Δ (1232 )+ production, W <1.4 GeV .

Measurement of ν μ charged-current single π 0 production on hydrocarbon in the few-GeV region using MINERvA

DOE PAGES

Altinok, O.; Le, T.; Aliaga, L.; ...

2017-10-01

The semiexclusive channel νμ+CH→μ-π0+nucleon(s) is analyzed using MINERvA exposed to the low-energy NuMI νμ beam with spectral peak at Eν≃3 GeV. Differential cross sections for muon momentum and production angle, π0 kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section σ(Eν) is obtained over the range 1.5 GeV≤Eν<20 GeV. Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for charged-current π+(π0) production by νμ(ν¯μ) neutrinos. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for Q2 that may reflectmore » shortfalls in modeling of interactions on carbon. For π0 kinematic distributions, however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as π0 mesons, the pπ0 invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the pπ0 system are measured in the region of Δ(1232)+ production, W<1.4 GeV.« less

Measurement of ν μ charged-current single π 0 production on hydrocarbon in the few-GeV region using MINERvA

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

Altinok, O.; Le, T.; Aliaga, L.

The semiexclusive channel νμ+CH→μ-π0+nucleon(s) is analyzed using MINERvA exposed to the low-energy NuMI νμ beam with spectral peak at Eν≃3 GeV. Differential cross sections for muon momentum and production angle, π0 kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section σ(Eν) is obtained over the range 1.5 GeV≤Eν<20 GeV. Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for charged-current π+(π0) production by νμ(ν¯μ) neutrinos. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for Q2 that may reflectmore » shortfalls in modeling of interactions on carbon. For π0 kinematic distributions, however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as π0 mesons, the pπ0 invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the pπ0 system are measured in the region of Δ(1232)+ production, W<1.4 GeV.« less

Electron capture in collisions of Al2+ ions with He atoms at intermediate energies

NASA Astrophysics Data System (ADS)

Watanabe, A.; Sato, H.; Gu, J. P.; Hirsch, G.; Buenker, R. J.; Kimura, M.

2001-09-01

Electron capture resulting from collisions of Al2+ ions with He atoms from 0.15 to 1000 keV/u is investigated using a molecular-orbital representation within a semiclassical frame. Molecular electronic states and corresponding couplings are determined by the ALCHEMY program. Sixteen molecular states all connecting to single-electron-capture processes are included, and hence radial and rotational couplings among these channels are fully considered. The trajectory effect arising from the straight-line, Coulomb, and ground-state potential trajectories for electron-capture and excitation processes is carefully assessed. The electron-capture cross section by ground-state Al2+(2S) ions slowly increases before it reaches a maximum of 1.3×10-16 cm2 at 100 keV/u. Those for metastable Al2+(2P) ions sharply increase with increasing energy, and reach a peak at 1 keV/u with a value of 1.5×10-16 cm2. The earlier experimental data are found to be larger by an order of magnitude although their energy dependence is in good accord with the present result. Excitation cross sections for both the ground and metastable states are found to be much larger by a factor of 2-3 than corresponding capture cross sections above 1 keV/u although they become comparable below this energy.

Prospects of heavy and superheavy element production via inelastic nucleus-nucleus collisions - from 238U+238U to18O+254Es

NASA Astrophysics Data System (ADS)

Schädel, Matthias

2016-12-01

Multi-nucleon transfer reactions, frequently termed deep-inelastic, between heavy-ion projectiles and actinide targets provide prospects to synthesize unknown isotopes of heavy actinides and superheavy elements with neutron numbers beyond present limits. The 238U on 238U reaction, which revealed essential aspects of those nuclear reactions leading to surviving heavy nuclides, mainly produced in 3n and 4n evaporation channels, is discussed in detail. Positions and widths of isotope distributions are compared. It is shown, as a general rule, that cross sections peak at irradiation energies about 10% above the Coulomb barrier. Heavy target nuclei are essential for maximizing cross sections. Experimental results from the 238U on 248Cm reaction, including empirical extrapolations, are compared with theoretical model calculations predicting relatively high cross sections for neutron-rich nuclei. Experiments to test the validity of such predictions are proposed. Comparisons between rather symmetric heavy-ion reactions like 238U on 248Cm (or heavier targets up to 254Es) with very asymmetric ones like 18O on 254Es reveal that the ones with 238U as a projectile have the highest potential in the superheavy element region while the latter ones can be advantageous for the synthesis of heavy actinide isotopes. Concepts for highly efficient recoil separators designed for transfer products are presented.

Multiple frequency backscatter observations of heater-induced field-aligned striations in the auroral E region

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

Noble, S.T.

1985-01-01

In September 1983 a series of HF ionospheric modification experiments were conducted in Scandinavia using the heat facility near Tromosoe Norway. The purpose of these experiments was to examine the mechanisms by which high-power HF radio waves produce geomagnetic field-aligned striations (FAS) in the auroral E region. The vast majority of the backscatter observations were made with radars operating at 47 and 144 MHz (STARE Finland). Additionally, limited observations were conducted at 140 (STARE Norway) and 21 MHz (SAFARI). These radars are sensitive to irregularities having scale lengths between 1 and 7 m across the geomagnetic field lines. During periodsmore » of full power O-mode heating, striations having peak cross sections of 40 to 50 dBsm are observed. Striations are not detected during times of X-mode heating. When the heater output is varied, a corresponding change in the cross section is measured. The magnitude of the change is most pronounced for heater level changes in the range 12.5 to 50% of full power. These cross sections are significantly larger than those measured at midlatitudes using the Arecibo heater (approx.10/sup 1/ m/sup 2/). This is consistent with theoretical studies which indicate that it is easier to excite short-scale FAS at places where the geomagnetic dip angle is large. The growth and decay times of the striations are frequency dependent.« less

Reduced cardiovascular fitness associated with exposure to clozapine in individuals with chronic schizophrenia.

PubMed

Kim, David D; Lang, Donna J; Procyshyn, Ric M; Woodward, Melissa L; Kaufman, Kai; White, Randall F; Honer, William G; Warburton, Darren E R

2018-04-01

Studies show that individuals with schizophrenia have impaired cardiovascular fitness (i.e., low peak aerobic power (VO 2 peak)). It is speculated that antipsychotics with adverse cardiovascular and metabolic profiles, in particular clozapine, have a significant impact on VO 2 peak. In this cross-sectional study, we examined whether exposure to clozapine was associated with further reduced VO 2 peak compared with non-clozapine antipsychotics. Thirty participants with chronic schizophrenia or schizoaffective disorder were divided into clozapine and non-clozapine groups. Mean daily doses of antipsychotics were standardized to chlorpromazine equivalents and haloperidol equivalents for antagonism of alpha 1 - and alpha 2 -adrenergic receptors. Participants completed an incremental-to-maximal symptom-limited exercise test on a cycle ergometer for the assessment of VO 2 peak. The clozapine group demonstrated significantly lower VO 2 peak than the non-clozapine group. Haloperidol equivalents for alpha-adrenergic receptor antagonism, but not chlorpromazine equivalents, demonstrated significant inverse associations with VO 2 peak. The clozapine group had a significantly higher amount of antagonistic activity at alpha-adrenergic receptors than the non-clozapine group. In conclusion, exposure to clozapine was associated with further reduced cardiovascular fitness, which may be explained by the drug's greater antagonistic activity at alpha-adrenergic receptors. Cardiovascular fitness needs to be promoted in individuals treated with antipsychotics, particularly clozapine, to prevent the risk of cardiovascular disease and mortality. Copyright © 2018 Elsevier B.V. All rights reserved.

Allometric modelling of peak oxygen uptake in male soccer players of 8-18 years of age.

PubMed

Valente-Dos-Santos, João; Coelho-E-Silva, Manuel J; Tavares, Óscar M; Brito, João; Seabra, André; Rebelo, António; Sherar, Lauren B; Elferink-Gemser, Marije T; Malina, Robert M

2015-03-01

Peak oxygen uptake (VO2peak) is routinely scaled as mL O2 per kilogram body mass despite theoretical and statistical limitations of using ratios. To examine the contribution of maturity status and body size descriptors to age-associated inter-individual variability in VO2peak and to present static allometric models to normalize VO2peak in male youth soccer players. Total body and estimates of total and regional lean mass were measured with dual energy X-ray absorptiometry in a cross-sectional sample of Portuguese male soccer players. The sample was divided into three age groups for analysis: 8-12 years, 13-15 years and 16-18 years. VO2peak was estimated using an incremental maximal exercise test on a motorized treadmill. Static allometric models were used to normalize VO2peak. The independent variables with the best statistical fit explained 72% in the younger group (lean body mass: k = 1.07), 52% in mid-adolescent players (lean body mass: k = 0.93) and 31% in the older group (body mass: k = 0.51) of variance in VO2peak. The inclusion of the exponential term pubertal status marginally increased the explained variance in VO2peak (adjusted R(2 )= 36-75%) and provided statistical adjustments to the size descriptors coefficients. The allometric coefficients and exponents evidenced the varying inter-relationship among size descriptors and maturity status with aerobic fitness from early to late-adolescence. Lean body mass, lean lower limbs mass and body mass combined with pubertal status explain most of the inter-individual variability in VO2peak among youth soccer players.

Initial Circulation and Peak Vorticity Behavior of Vortices Shed from Airfoil Vortex Generators

NASA Technical Reports Server (NTRS)

Wendt, Bruce J.; Biesiadny, Tom (Technical Monitor)

2001-01-01

An extensive parametric study of vortices shed from airfoil vortex generators has been conducted to determine the dependence of initial vortex circulation and peak vorticity on elements of the airfoil geometry and impinging flow conditions. These elements include the airfoil angle of attack, chord length, span, aspect ratio, local boundary layer thickness, and free stream Mach number. In addition, the influence of airfoil-to-airfoil spacing on the circulation and peak vorticity has been examined for pairs of co-rotating and counter-rotating vortices. The vortex generators were symmetric airfoils having a NACA-0012 cross-sectional profile. These airfoils were mounted either in isolation, or in pairs, on the surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio was about 17 percent. The circulation and peak vorticity data were derived from cross-plane velocity measurements acquired with a seven-hole probe at one chord-length downstream of the airfoil trailing edge location. The circulation is observed to be proportional to the free-stream Mach number, the angle-of-attack, and the span-to-boundary layer thickness ratio. With these parameters held constant, the circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio. The peak vorticity is also observed to be proportional to the free-stream Mach number, the airfoil angle-of-attack, and the span-to-boundary layer thickness ratio. Unlike circulation, however, the peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at an aspect ratio of about 2.0 before falling off again at higher values of aspect ratio. Co-rotating vortices shed from closely spaced pairs of airfoils have values of circulation and peak vorticity under those values found for vortices shed from isolated airfoils of the same geometry. Conversely, counter-rotating vortices show enhanced values of circulation and peak vorticity when compared to values obtained in isolation. The circulation may be accurately modeled with an expression based on Prandtl's relationship between finite airfoil circulation and airfoil geometry. A correlation for the peak vorticity has been derived from a conservation relationship equating the moment at the airfoil tip to the rate of angular momentum production of the shed vortex, modeled as a Lamb (ideal viscous) vortex. This technique provides excellent qualitative agreement to the observed behavior of peak vorticity for low aspect ratio airfoils typically used as vortex generators.

Search for weak M 1 transitions in 48Ca with inelastic proton scattering

NASA Astrophysics Data System (ADS)

Mathy, M.; Birkhan, J.; Matsubara, H.; von Neumann-Cosel, P.; Pietralla, N.; Ponomarev, V. Yu.; Richter, A.; Tamii, A.

2017-05-01

Background: The quenching of spin-isospin modes in nuclei is an important field of research in nuclear structure. It has an impact on astrophysical reaction rates and on fundamental processes like neutrinoless double-β decay. Gamow-Teller (GT) and spin-flip M 1 strengths are quenched. Concerning the latter, the Jπ=1+ resonance in the doubly magic nucleus 48Ca, dominated by a single transition, serves as a reference case. Purpose: The aim of the present work is to search for weak M 1 transitions in 48Ca with a high-resolution (p ,p') experiment at 295 MeV and forward angles including 0∘ and a comparison with results from a similar study using backward-angle electron scattering at low momentum transfers in order to estimate their contribution to the total B (M 1 ) strength in 48Ca. Methods: The spin-M 1 cross sections of individual peaks in the spectra are deduced with a multipole decomposition analysis (MDA) and converted to reduced spin-M 1 transition strengths by using the unit cross-section method. For a comparison with electron-scattering results, corresponding reduced B (M 1 ) transition strengths are extracted following the approach outlined in Birkhan et al. [Phys. Rev. C 93, 041302(R) (2016), 10.1103/PhysRevC.93.041302]. Results: In total, 30 peaks containing a M 1 contribution are found in the excitation energy region 7-13 MeV. The resulting B (M 1 ) strength distribution compares well to the electron-scattering results considering different factors limiting the sensitivity in both experiments and the enhanced importance of mechanisms breaking the proportionality of nuclear cross sections and electromagnetic matrix elements for weak transitions as studied here. The total strength of 1.14(7) μN2 deduced assuming a nonquenched isoscalar part of the (p ,p') cross sections agrees with the (e ,e') result of 1.21(13) μN2. A bin-wise analysis above 10 MeV provides an upper limit of 1.51(17) μN2. Conclusions: The present results confirm the previous electron-scattering work that weak transitions contribute about 25% to the total B (M 1 ) strength in 48Ca and the quenching factors of GT and spin-M 1 strength are then comparable in f p -shell nuclei. Thus, the role of meson-exchange currents seems to be negligible in 48Ca, in contrast to s d -shell nuclei.

X-Ray Fluorescence Solvent Detection at the Substrate-Adhesive Interface

NASA Technical Reports Server (NTRS)

Wurth, Laura; Evans, Kurt; Weber, Bart; Headrick, Sarah

2005-01-01

With environmental regulations limiting the use of volatile organic compounds, low-vapor pressure solvents have replaced traditional degreasing solvents for bond substrate preparation. When used to clean and prepare porous bond substrates such as phenolic composites, low vapor pressure solvents can penetrate deep into substrate pore networks and remain there for extended periods. Trapped solvents can interact with applied adhesives either prior to or during cure, potentially compromising bond properties. Currently, methods for characterizing solvent time-depth profiles in bond substrates are limited to bulk gravimetric or sectioning techniques. While sectioning techniques such as microtome allow construction of solvent depth profiles, their depth resolution and reliability are limited by substrate type. Sectioning techniques are particularly limited near the adhesive-substrate interface where depth resolution is further limited by adhesive-substrate hardness and, in the case of a partially cured adhesive, mechanical properties differences. Additionally, sectioning techniques cannot provide information about lateral solvent diffusion. Cross-section component mapping is an alternative method for measuring solvent migration in porous substrates that eliminates the issues associated with sectioning techniques. With cross-section mapping, the solvent-wiped substrate is sectioned perpendicular rather than parallel to the wiped surface, and the sectioned surface is analyzed for the solvent or solvent components of interest using a two-dimensional mapping or imaging technique. Solvent mapping can be performed using either direct or indirect methods. With a direct method, one or more solvent components are mapped using red or Raman spectroscopy together with a moveable sample stage and/or focal plane array detector. With an indirect method, an elemental "tag" not present in the substrate is added to the solvent before the substrate is wiped. Following cross sectioning, the tag element can then be mapped by its characteristic x-ray emission using either x-ray fluorescence, or electron-beam energy-and wavelength-dispersive x-ray spectrometry. The direct mapping techniques avoid issues of different diffusion or migration rates of solvents and elemental tags, while the indirect techniques avoid spectral resolution issues in cases where solvents and substrates have adjacent or overlapping peaks. In this study, cross-section component indirect mapping is being evaluated as a method for measuring migration of d-limonene based solvents in glass-cloth phenolic composite (GCP) prior to and during subsequent bonding and epoxy adhesive cure.

Design of Multi-Resonant Cavities Based on Metal-Coated Dielectric Nanocylinders

NASA Astrophysics Data System (ADS)

Dong, Junyuan; Yu, Guanxia; Fu, Jingjing; Luo, Min; Du, Wenwen

2018-06-01

In this paper, the light scattering properties for multiple silver-coated dielectric nanocylinders with the symmetrical distribution were investigated. Based on the transfer matrix method, we derive the general transmission and reflection coefficient matrices for multiple dielectric nanocylinders. When the incident light frequencies are less than the plasma frequencies, the surface plasmons (SPs) appear in the interface between the silver and dielectrics. Numerical simulations show that there are three peaks of absorption cross-section (ACS) in the relationship between the ACS and the frequencies of the incident light, when the distance between the silver-coated dielectric nanocylinders is chosen properly. These SPs resonance peaks are characterised as resonances intrinsic to the cylindrically periodic system corresponding to different inner cavity structures. These multi-resonant cavities may have potential applications in integrated devices, optical sensors and optical storage devices.

Analyzing the thermionic reactor critical experiments. [thermal spectrum of uranium 235 core

NASA Technical Reports Server (NTRS)

Niederauer, G. F.

1973-01-01

The Thermionic Reactor Critical Experiments (TRCE) consisted of fast spectrum highly enriched U-235 cores reflected by different thicknesses of beryllium or beryllium oxide with a transition zone of stainless steel between the core and reflector. The mixed fast-thermal spectrum at the core reflector interface region poses a difficult neutron transport calculation. Calculations of TRCE using ENDF/B fast spectrum data and GATHER library thermal spectrum data agreed within about 1 percent for the multiplication factor and within 6 to 8 percent for the power peaks. Use of GAM library fast spectrum data yielded larger deviations. The results were obtained from DOT R Theta calculations with leakage cross sections, by region and by group, extracted from DOT RZ calculations. Delineation of the power peaks required extraordinarily fine mesh size at the core reflector interface.

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

Brummer, Gordie, E-mail: gbrummer@bu.edu; Photonics Center, Boston University, Boston, Massachusetts 02215; Nothern, Denis

Distributed Bragg reflectors (DBRs) with peak reflectivity at approximately 280 nm, based on compositionally graded Al{sub x}Ga{sub 1−x}N alloys, were grown on 6H-SiC substrates by plasma-assisted molecular beam epitaxy. DBRs with square, sinusoidal, triangular, and sawtooth composition profiles were designed with the transfer matrix method. The crystal structure of these DBRs was studied with high-resolution x-ray diffraction of the (1{sup ¯}015) reciprocal lattice point. The periodicity of the DBR profiles was confirmed with cross-sectional Z-contrast scanning transmission electron microscopy. The peak reflectance of these DBRs with 15.5 periods varies from 77% to 56% with corresponding full width at half maximum ofmore » 17–14 nm. Coupled mode analysis was used to explain the dependence of the reflectivity characteristics on the profile of the graded composition.« less

Raman Spectroscopy for Mineral Identification and Quantification for in situ Planetary Surface Analysis: A Point Count Method

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Wang, Alian; Rockow, Kaylynn M.; Jolliff, Bradley L.; Korotev, Randy L.; Viskupic, Karen M.

1997-01-01

Quantification of mineral proportions in rocks and soils by Raman spectroscopy on a planetary surface is best done by taking many narrow-beam spectra from different locations on the rock or soil, with each spectrum yielding peaks from only one or two minerals. The proportion of each mineral in the rock or soil can then be determined from the fraction of the spectra that contain its peaks, in analogy with the standard petrographic technique of point counting. The method can also be used for nondestructive laboratory characterization of rock samples. Although Raman peaks for different minerals seldom overlap each other, it is impractical to obtain proportions of constituent minerals by Raman spectroscopy through analysis of peak intensities in a spectrum obtained by broad-beam sensing of a representative area of the target material. That is because the Raman signal strength produced by a mineral in a rock or soil is not related in a simple way through the Raman scattering cross section of that mineral to its proportion in the rock, and the signal-to-noise ratio of a Raman spectrum is poor when a sample is stimulated by a low-power laser beam of broad diameter. Results obtained by the Raman point-count method are demonstrated for a lunar thin section (14161,7062) and a rock fragment (15273,7039). Major minerals (plagioclase and pyroxene), minor minerals (cristobalite and K-feldspar), and accessory minerals (whitlockite, apatite, and baddeleyite) were easily identified. Identification of the rock types, KREEP basalt or melt rock, from the 100-location spectra was straightforward.

Comparison of Cyclic Hysteresis Behavior between Cross-Ply C/SiC and SiC/SiC Ceramic-Matrix Composites

PubMed Central

Li, Longbiao

2016-01-01

In this paper, the comparison of cyclic hysteresis behavior between cross-ply C/SiC and SiC/SiC ceramic-matrix composites (CMCs) has been investigated. The interface slip between fibers and the matrix existed in the matrix cracking mode 3 and mode 5, in which matrix cracking and interface debonding occurred in the 0° plies are considered as the major reason for hysteresis loops of cross-ply CMCs. The hysteresis loops of cross-ply C/SiC and SiC/SiC composites corresponding to different peak stresses have been predicted using present analysis. The damage parameter, i.e., the proportion of matrix cracking mode 3 in the entire matrix cracking modes of the composite, and the hysteresis dissipated energy increase with increasing peak stress. The damage parameter and hysteresis dissipated energy of C/SiC composite under low peak stress are higher than that of SiC/SiC composite; However, at high peak stress, the damage extent inside of cross-ply SiC/SiC composite is higher than that of C/SiC composite as more transverse cracks and matrix cracks connect together. PMID:28787861

Comparison of Cyclic Hysteresis Behavior between Cross-Ply C/SiC and SiC/SiC Ceramic-Matrix Composites.

PubMed

Li, Longbiao

2016-01-19

In this paper, the comparison of cyclic hysteresis behavior between cross-ply C/SiC and SiC/SiC ceramic-matrix composites (CMCs) has been investigated. The interface slip between fibers and the matrix existed in the matrix cracking mode 3 and mode 5, in which matrix cracking and interface debonding occurred in the 0° plies are considered as the major reason for hysteresis loops of cross-ply CMCs. The hysteresis loops of cross-ply C/SiC and SiC/SiC composites corresponding to different peak stresses have been predicted using present analysis. The damage parameter, i.e. , the proportion of matrix cracking mode 3 in the entire matrix cracking modes of the composite, and the hysteresis dissipated energy increase with increasing peak stress. The damage parameter and hysteresis dissipated energy of C/SiC composite under low peak stress are higher than that of SiC/SiC composite; However, at high peak stress, the damage extent inside of cross-ply SiC/SiC composite is higher than that of C/SiC composite as more transverse cracks and matrix cracks connect together.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing.

PubMed

Sharma, Rakesh

2010-07-21

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

NASA Astrophysics Data System (ADS)

Sharma, Rakesh

2010-07-01

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

A Consistent Wave Impact Load Model for Studying Structure, Equipment Ruggedness, Shock Isolation Seats, and Human Comfort in Small High Speed Craft

DTIC Science & Technology

2016-11-01

acceleration at a cross-section was used as a measure of the wave impact load in units of g. Later developments included publication of the envelope...Republic, 4 – 7 October 2004. PICKFORD, E.V., MAHONE, R.R., WOLK, H.L. (1975). Slam/Shock Isolation Pedestal, United States Patent Number, 3,912,248, 14...accelerations. The rigid body peak acceleration is a measure of the impact load in units of g. In the following plots the data corresponds to head-sea

The possibility of a new resonance of three-body linear chain structure in the reaction 12C+16O at Ec.mapprox-33.5MeV

NASA Astrophysics Data System (ADS)

Kong, Xiangjing; P, L. Li; J, J. Kolata; A, Morsad; L, Goetting; R, A. Kryger; S, Dixit; R, Tighe; W, Chune

1990-05-01

There is a peak in the excitation function of total cross section of low energy α-particles in the reaction 12C+16O at Ec.m approx33.5MeV. The experimental distribution of α-particle emitted event has been obtained. The result of theoretical calculation roughly agrees with experimental data, gives an orientation where three-body resonances can be expected, and the information on internal structure of three-body linear chain molecule.

SU-E-J-149: Secondary Emission Detection for Improved Proton Relative Stopping Power Identification

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

Saunders, J; Musall, B; Erickson, A

Purpose: This research investigates application of secondary prompt gamma (PG) emission spectra, resulting from nuclear reactions induced by protons, to characterize tissue composition along the particle path. The objective of utilizing the intensity of discrete high-energy peaks of PG is to improve the accuracy of relative stopping power (RSP) values available for proton therapy treatment planning on a patient specific basis and to reduce uncertainty in dose depth calculations. Methods: In this research, MCNP6 was used to simulate PG emission spectra generated from proton induced nuclear reactions in medium of varying composition of carbon, oxygen, calcium and nitrogen, the predominantmore » elements found in human tissue. The relative peak intensities at discrete energies predicted by MCNP6 were compared to the corresponding atomic composition of the medium. Results: The results have shown a good general agreement with experimentally measured values reported by other investigators. Unexpected divergence from experimental spectra was noted in the peak intensities for some cases depending on the source of the cross-section data when using compiled proton table libraries vs. physics models built into MCNP6. While the use of proton cross-section libraries is generally recommended when available, these libraries lack data for several less abundant isotopes. This limits the range of their applicability and forces the simulations to rely on physics models for reactions with natural atomic compositions. Conclusion: Current end-of-range proton imaging provides an average RSP for the total estimated track length. The accurate identification of tissue composition along the incident particle path using PG detection and characterization allows for improved determination of the tissue RSP on the local level. While this would allow for more accurate depth calculations resulting in tighter treatment margins, precise understanding of proton beam behavior in tissue of various compositions is necessary requiring detailed simulations with a high degree of accuracy.« less

Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners: A cross-sectional study.

PubMed

Fong, Shirley S M; Chan, Jessie S M; Bae, Young-Hyeon; Yam, Timothy T T; Chung, Louisa M Y; Ma, Ada W W; Kuisma, Raija

2017-01-01

This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners.Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively.VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P < 0.001), a 60.8% higher isokinetic body weight-adjusted peak torque of knee flexors (P < 0.001), and a 31.4% shorter time to reach peak torque in the knee flexors (P = 0.001) than the active controls. No significant differences were found in any of the other musculoskeletal outcomes between the 2 groups (P > 0.05).Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults.

ISOKINETIC KNEE MUSCLE STRENGTH PROFILE IN BRAZILIAN MALE SOCCER, FUTSAL, AND BEACH SOCCER PLAYERS: A CROSS-SECTIONAL STUDY

PubMed Central

Mascarin, Naryana C.; Vargas, Valentine Z.; Vancini, Rodrigo L.; Andrade, Marília S.

2017-01-01

Background Anterior cruciate ligament injury is higher in soccer athletes as compared to athletes of other sports. Risk factors for anterior cruciate ligament injury include low knee hamstring/quadriceps strength ratio and bilateral strength deficits. Purpose To investigate isokinetic thigh muscles strength, hamstring/quadriceps strength ratio, and bilateral strength comparisons in athletes who participate in professional soccer, futsal, and beach soccer. Study Design Cross-sectional study. Methods Brazilian professional soccer (n=70), futsal (n=30), and beach soccer (n=12) players were isokinetically assessed to examine strength of knee extensors and flexors at 60 degrees/second in concentric mode, to measure peak torque of dominant and non-dominant limbs. Results In the dominant limb, for extensors muscles, futsal players presented significantly lower peak torque values (223.9 ± 33.4 Nm) than soccer (250.9 ± 43.0 Nm; p=0.02) and beach soccer players (253.1 ± 32.4 Nm; p=0.03). Peak torque for extensor muscles in the non-dominant limb was significantly lower in futsal (224.0 ± 35.8 Nm) than in beach soccer players (256.8 ± 39.8 Nm; p=0.03). Hamstring/quadriceps strength ratio for dominant limbs for futsal (57.6 ± 10.1%), soccer (53.5 ± 8.8%), and beach soccer (56.3 ± 8.4%) players presented no significant differences between groups; however, the mean values were lower than recommended values found in the literature. There were no strength deficits for any of the evaluated groups when compared bilaterally. Conclusions Futsal athletes presented lower values for quadriceps strength than soccer and beach soccer athletes. Futsal, soccer, and beach soccer players presented no strength asymmetries, but they presented with strength imbalance in hamstring/quadriceps strength ratio. Level of Evidence 3 PMID:29234562

Radial secondary electron dose profiles and biological effects in light-ion beams based on analytical and Monte Carlo calculations using distorted wave cross sections.

PubMed

Wiklund, Kristin; Olivera, Gustavo H; Brahme, Anders; Lind, Bengt K

2008-07-01

To speed up dose calculation, an analytical pencil-beam method has been developed to calculate the mean radial dose distributions due to secondary electrons that are set in motion by light ions in water. For comparison, radial dose profiles calculated using a Monte Carlo technique have also been determined. An accurate comparison of the resulting radial dose profiles of the Bragg peak for (1)H(+), (4)He(2+) and (6)Li(3+) ions has been performed. The double differential cross sections for secondary electron production were calculated using the continuous distorted wave-eikonal initial state method (CDW-EIS). For the secondary electrons that are generated, the radial dose distribution for the analytical case is based on the generalized Gaussian pencil-beam method and the central axis depth-dose distributions are calculated using the Monte Carlo code PENELOPE. In the Monte Carlo case, the PENELOPE code was used to calculate the whole radial dose profile based on CDW data. The present pencil-beam and Monte Carlo calculations agree well at all radii. A radial dose profile that is shallower at small radii and steeper at large radii than the conventional 1/r(2) is clearly seen with both the Monte Carlo and pencil-beam methods. As expected, since the projectile velocities are the same, the dose profiles of Bragg-peak ions of 0.5 MeV (1)H(+), 2 MeV (4)He(2+) and 3 MeV (6)Li(3+) are almost the same, with about 30% more delta electrons in the sub keV range from (4)He(2+)and (6)Li(3+) compared to (1)H(+). A similar behavior is also seen for 1 MeV (1)H(+), 4 MeV (4)He(2+) and 6 MeV (6)Li(3+), all classically expected to have the same secondary electron cross sections. The results are promising and indicate a fast and accurate way of calculating the mean radial dose profile.

Update on diode-pumped solid-state laser experiments for inertial fusion energy

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

Marshall, C.; Smith, L.; Payne, S.

The authors have completed the initial phase of the diode-pumped solid-state laser (DPSSL) experimental program to validate the expected pumping dynamics and extraction cross-sections of Yb{sup 3+}-doped Sr{sub 5}(PO{sub 4}){sub 3}F (Yb:S-FAP) crystals. Yb:S-FAP crystals up to 25 x 25 x 175 mm in size have been grown for this purpose which have acceptable loss characteristics (<1 %/cm) and laser damage thresholds ({approximately}20 J/cm{sup 2}). The saturation fluence for pumping has been measured to be 2.2 J/cm{sup 2} using three different methods based on either the spatial, temporal, or energy transmission properties of a Yb:S-FAP rod. The small signal gainmore » under saturated pumping conditions was measured. These measurements imply an emission cross section of 6.0 x 10{sup {minus}20} cm{sup 2} that falls within error bars of the previously reported value of 7.3 x 10{sup {minus}20} cm{sup 2}, obtained from purely spectroscopic techniques. The effects of radiation trapping on the emission lifetime have been quantified. The long lifetime of Yb:S-FAP has beneficial effects for diode-pumped amplifier designs, relative to materials with equivalent cross sections but shorter lifetimes, in that less peak pump intensity is required (thus lower diode costs) and that lower spontaneous emission rates lead to a reduction in amplified spontaneous emission. Consequently, up to 1.7 J/cm{sup 3} of stored energy density was achieved in a 6x6x44 mm Yb:S-FAP amplifier rod; this stored energy density is large relative to typical flashlamp-pumped Nd:glass values of 0.3 to 0.5 J/cm{sup 3}. A 2.4 kW peak power InGaAs diode array has been fabricated by Beach, Emanuel, and co-workers which meets the central wavelength, bandwidth, and energy specifications for the author`s immediate experiments. These results further increase their optimism of being able to produce a {approximately} 10% efficient diode-pumped solid state laser for inertial fusion energy.« less

Morphological Study of Poly(vinylbenzyl chloride)-Grafted Poly(ethylene-co-tetrafluoroethylene) [ETFE-g-PVBC] Films Using Small-Angle Neutron Scattering Analysis.

PubMed

Song, J M; Ko, B S; Sohn, J Y; Shin, J

2016-06-01

In this study, the effect of degree of the grafting and crosslinking on the morphology of the crystalline domain in poly(vinylbenzyl chloride)-grafted poly(ethylene-co-tetrafluoroethylene) [ETFE-g-PVBC] films was investigated using a SANS (small-angle neutron scattering) analysis. The grafted films can be used as a precursor for ion-exchange membrane. ETFE-g-PVBC films with various degrees of cross-linking were prepared by a simultaneous irradiation grafting of vinylbenzyl chloride (VBC) and divinylbenzene (DVB) onto an ETFE film. The SEM-EDX (scanning electron microscopy-energy dispersive X-ray spectroscopy) results of a cross-sectional distribution of ETFE-g-PVBC films showed that the chlorine atoms were well-distributed throughout the films. SANS profiles of the PVBC-grafted films in the absence of a DVB crosslinker showed that the crystalline domain peaks were observed and the peak maximum position shifted significantly from 0.032 Å-(-1) to 0.02 Å(-1) with an increase in the degree of grafting. However, peak maximum positions of the PVBC-grafted films in the presence of a DVB crosslinker shifted slightly from 0.02 Å(-1) to 0.024 Å(-1) with an increase in the amount of DVB monomer at same degree of grafting. These results indicate that the degree of grafting and crosslinking affect the morphology of the crystalline domain in the ETFE-g-PVBC films.

Communication: nanosecond folding dynamics of an alpha helix: time-dependent 2D-IR cross peaks observed using polarization-sensitive dispersed pump-probe spectroscopy.

PubMed

Panman, Matthijs R; van Dijk, Chris N; Meuzelaar, Heleen; Woutersen, S

2015-01-28

We present a simple method to measure the dynamics of cross peaks in time-resolved two-dimensional vibrational spectroscopy. By combining suitably weighted dispersed pump-probe spectra, we eliminate the diagonal contribution to the 2D-IR response, so that the dispersed pump-probe signal contains the projection of only the cross peaks onto one of the axes of the 2D-IR spectrum. We apply the method to investigate the folding dynamics of an alpha-helical peptide in a temperature-jump experiment and find characteristic folding and unfolding time constants of 260 ± 30 and 580 ± 70 ns at 298 K.

Pion Elastic Scattering and the (pion Pion' Proton) Reaction on HELIUM-4 in the DELTA(3,3) Region

NASA Astrophysics Data System (ADS)

Jones, Mark Kevin

This dissertation presents measurements and analyses of pi^+ and pi ^{-} elastic scattering, and ( pi^{+}, pi^ {+^'}p) and ( pi^{-},pi^{-^ '}p) reactions on ^4 He. Both experiments were done at the Los Alamos Meson Physics Facility using the Energetic Pion Channel and Spectrometer. The ^4He( pi,pi) elastic scattering cross sections were measured for pi^{+} scattering at scattering angles theta _{lab} = 110^circ -170^circ and five incident energies between T_{pi } = 90 and 180 MeV. Elastic pi ^{-} cross sections were measured only at T_{pi} = 180 MeV. The ^4He(pi, pi' p) angular correlation functions were measured for pi^{+} and pi^{-} at T_{pi} = 180 and theta_{pi^' } = 30^circ, 40 ^circ, 60^circ , 80^circ and at T _pi = 140 MeV and theta_{pi^'} = 40^circ. Using scintillators at eight angles the protons were detected in coincidence with the inelastically scattered pions. In the ^4He(pi, pi^' p) experiment unexpectedly large ratios R_{pi p} = {sigma(pi^{+}, pi^{+} p)}over{sigma( pi^{-},pi^{-} p)} of up to 50 were observed near the quasi -free angle in the angular correlation functions summed over 30.5 to 39.5 MeV in ^4He excitation energy. The (pi,pi' p) data were analyzed by a distorted wave impulse approximation code 3DEE (Ch 82), (Re 82). 3DEE models the ( pi,pi' p) reaction as a pion -induced proton knock-out and includes distortions in the incident pion, the outgoing pion, and the emitted proton waves. The calculations give R_{pi p} between 6 and 9 at all proton and pion angles. The pi^{+} calculations reproduce the absolute pi^ {+} cross sections fairly well. The pi^{-} calculations have a peak in the angular correlation function near the quasi-free angle, in contrast to the pi^ {-} data which displays a flat distribution. At proton angles near 180^circ in the center of mass of the struck mass 4 system, the measured pi^{-} cross sections are larger than the pi^ {+} cross section which is the reverse of the ratio at 0^circ. These features of the measured pi^- cross sections indicate that interference between a quasi -free process and another process is important in the ( pi,pi^' p) reaction. The measurement of ^4He( pi,pi) elastic scattering data at theta_pi = 110 ^circ-170^circ extends the angular range of previous ^4He(pi,pi) data measured at EPICS. The experiment provides high quality elastic scattering data at backward angles. The pi^{-} elastic cross section at T_pi = 180 MeV measured for this dissertation when extrapolated to theta _{cm} = 180^circ is about a factor of two smaller than the cross section measured previously at CERN (Ref. (Bi 78)). The data were analyzed using a microscopic optical model and by a phase shift fit.

Method and apparatus for analog pulse pile-up rejection

DOEpatents

De Geronimo, Gianluigi

2013-12-31

A method and apparatus for pulse pile-up rejection are disclosed. The apparatus comprises a delay value application constituent configured to receive a threshold-crossing time value, and provide an adjustable value according to a delay value and the threshold-crossing time value; and a comparison constituent configured to receive a peak-occurrence time value and the adjustable value, compare the peak-occurrence time value with the adjustable value, indicate pulse acceptance if the peak-occurrence time value is less than or equal to the adjustable value, and indicate pulse rejection if the peak-occurrence time value is greater than the adjustable value.

Method and apparatus for analog pulse pile-up rejection

DOEpatents

De Geronimo, Gianluigi

2014-11-18

A method and apparatus for pulse pile-up rejection are disclosed. The apparatus comprises a delay value application constituent configured to receive a threshold-crossing time value, and provide an adjustable value according to a delay value and the threshold-crossing time value; and a comparison constituent configured to receive a peak-occurrence time value and the adjustable value, compare the peak-occurrence time value with the adjustable value, indicate pulse acceptance if the peak-occurrence time value is less than or equal to the adjustable value, and indicate pulse rejection if the peak-occurrence time value is greater than the adjustable value.

Germ cell loss induced by 12C6+ ion irradiation in young female mice.

PubMed

Zhang, Hong; Zhang, Xu; Yuan, Zhigang; Li, Xiaoda; Li, Wenjian; Zhou, Qingming; Min, Fengling; Xie, Yi; Liu, Bing; Duan, Xin

2006-06-01

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of 12C6+ ion in the Bragg peak or the plateau region. At 10th day after irradiation, ovarian and uterine weights were measured; normal and atretic (identified with the oocyte to be degenerating or absent) primordial, primary and preantral follicles were identified in the largest cross-section of each ovary. Percentage (%) of normal follicles of each developmental stage of oogenesis was calculated. The data showed that compared to controls, there was a dose-related decrease in percentage of normal follicles in each developmental stage. And the weights of ovary and uterus were also reduced with doses of irradiation. Moreover, these effects were much more significant in the Bragg peak region and the region close to the Bragg peak than in the beam's entrance (the plateau region). Radiosensitivity varied in different follicle maturation stages. Primordial follicles, which are thought to be extremely sensitive to ionizing irradiation, were reduced by 86.6%, while primary and preantral follicles reduced only by 72.5% and 61.8% respectively, by exposure with 6 Gy of 12C6+ ion in the Bragg peak region and the region close to the Bragg peak. The data suggested that due to their optimal depth-dose distribution in the Bragg peak region, heavy ions are ones of the best particles for radiotherapy of tumors located next of vital organs or/and surrounded by normal tissues, especially radiosensitive tissues such as gonads.

A calculation and uncertainty evaluation method for the effective area of a piston rod used in quasi-static pressure calibration

NASA Astrophysics Data System (ADS)

Gu, Tingwei; Kong, Deren; Shang, Fei; Chen, Jing

2018-04-01

This paper describes the merits and demerits of different sensors for measuring propellant gas pressure, the applicable range of the frequently used dynamic pressure calibration methods, and the working principle of absolute quasi-static pressure calibration based on the drop-weight device. The main factors affecting the accuracy of pressure calibration are analyzed from two aspects of the force sensor and the piston area. To calculate the effective area of the piston rod and evaluate the uncertainty between the force sensor and the corresponding peak pressure in the absolute quasi-static pressure calibration process, a method for solving these problems based on the least squares principle is proposed. According to the relevant quasi-static pressure calibration experimental data, the least squares fitting model between the peak force and the peak pressure, and the effective area of the piston rod and its measurement uncertainty, are obtained. The fitting model is tested by an additional group of experiments, and the peak pressure obtained by the existing high-precision comparison calibration method is taken as the reference value. The test results show that the peak pressure obtained by the least squares fitting model is closer to the reference value than the one directly calculated by the cross-sectional area of the piston rod. When the peak pressure is higher than 150 MPa, the percentage difference is less than 0.71%, which can meet the requirements of practical application.

Simultaneous quantification and identification of individual chemicals in metabolite mixtures by two-dimensional extrapolated time-zero (1)H-(13)C HSQC (HSQC(0)).

PubMed

Hu, Kaifeng; Westler, William M; Markley, John L

2011-02-16

Quantitative one-dimensional (1D) (1)H NMR spectroscopy is a useful tool for determining metabolite concentrations because of the direct proportionality of signal intensity to the quantity of analyte. However, severe signal overlap in 1D (1)H NMR spectra of complex metabolite mixtures hinders accurate quantification. Extension of 1D (1)H to 2D (1)H-(13)C HSQC leads to the dispersion of peaks along the (13)C dimension and greatly alleviates peak overlapping. Although peaks are better resolved in 2D (1)H-(13)C HSQC than in 1D (1)H NMR spectra, the simple proportionality of cross peaks to the quantity of individual metabolites is lost by resonance-specific signal attenuation during the coherence transfer periods. As a result, peaks for individual metabolites usually are quantified by reference to calibration data collected from samples of known concentration. We show here that data from a series of HSQC spectra acquired with incremented repetition times (the time between the end of the first (1)H excitation pulse to the beginning of data acquisition) can be extrapolated back to zero time to yield a time-zero 2D (1)H-(13)C HSQC spectrum (HSQC(0)) in which signal intensities are proportional to concentrations of individual metabolites. Relative concentrations determined from cross peak intensities can be converted to absolute concentrations by reference to an internal standard of known concentration. Clustering of the HSQC(0) cross peaks by their normalized intensities identifies those corresponding to metabolites present at a given concentration, and this information can assist in assigning these peaks to specific compounds. The concentration measurement for an individual metabolite can be improved by averaging the intensities of multiple, nonoverlapping cross peaks assigned to that metabolite.

Beyond Bernoulli

PubMed Central

Donati, Fabrizio; Myerson, Saul; Bissell, Malenka M.; Smith, Nicolas P.; Neubauer, Stefan; Monaghan, Mark J.; Nordsletten, David A.

2017-01-01

Background— Transvalvular peak pressure drops are routinely assessed noninvasively by echocardiography using the Bernoulli principle. However, the Bernoulli principle relies on several approximations that may not be appropriate, including that the majority of the pressure drop is because of the spatial acceleration of the blood flow, and the ejection jet is a single streamline (single peak velocity value). Methods and Results— We assessed the accuracy of the Bernoulli principle to estimate the peak pressure drop at the aortic valve using 3-dimensional cardiovascular magnetic resonance flow data in 32 subjects. Reference pressure drops were computed from the flow field, accounting for the principles of physics (ie, the Navier–Stokes equations). Analysis of the pressure components confirmed that the spatial acceleration of the blood jet through the valve is most significant (accounting for 99% of the total drop in stenotic subjects). However, the Bernoulli formulation demonstrated a consistent overestimation of the transvalvular pressure (average of 54%, range 5%–136%) resulting from the use of a single peak velocity value, which neglects the velocity distribution across the aortic valve plane. This assumption was a source of uncontrolled variability. Conclusions— The application of the Bernoulli formulation results in a clinically significant overestimation of peak pressure drops because of approximation of blood flow as a single streamline. A corrected formulation that accounts for the cross-sectional profile of the blood flow is proposed and adapted to both cardiovascular magnetic resonance and echocardiographic data. PMID:28093412

Feasibility and acceptability of using jumping mechanography to detect early components of sarcopenia in community-dwelling older women

PubMed Central

Hannam, K.; Hartley, A.; Clark, E.M.; Sayer, A. Aihie; Tobias, J.H.; Gregson, C.L.

2017-01-01

Objective: To determine the feasibility and acceptability of using peak power and force, measured by jumping mechanography (JM), to detect early age-related features of sarcopenia in older women. Methods: Community-dwelling women aged 71-87 years were recruited into this cross-sectional study. Physical function tests comprised the short physical performance battery (SPPB), grip strength and, if SPPB score≥6, JM. JM measured peak weight-adjusted power and force from two-footed jumps and one-legged hops respectively. Questionnaires assessed acceptability. Results: 463 women were recruited; 37(8%) with SPPB<6 were ineligible for JM. Of 426 remaining, 359(84%) were able to perform ≥1 valid two-footed jump, 300(70%) completed ≥1 valid one-legged hop. No adverse events occurred. Only 14% reported discomfort. Discomfort related to JM performance, with inverse associations with both power and force (p<0.01). Peak power and force respectively explained 8% and 10% of variance in SPPB score (13% combined); only peak power explained additional variance in grip strength (17%). Conclusions: Peak power and force explained a significant, but limited, proportion of variance in SPPB and grip strength. JM represents a safe and acceptable clinical tool for evaluating lower-limb muscle power and force in older women, detecting distinct components of muscle function, and possibly sarcopenia, compared to those evaluated by more established measures. PMID:28860427

Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

PubMed

Milner, Clare E; Hamill, Joseph; Davis, Irene S

2010-02-01

Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

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

Cary, Theodore W.; Sultan, Laith R.; Sehgal, Chandra M., E-mail: sehgalc@uphs.upenn.edu

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced eachmore » phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.« less

The relationship between pain and dynamic knee joint loading in knee osteoarthritis varies with radiographic disease severity. A cross sectional study.

PubMed

Henriksen, Marius; Aaboe, Jens; Bliddal, Henning

2012-08-01

In a cross sectional study, we investigated the relationships between knee pain and mechanical loading across the knee, as indicated by the external knee adduction moment (KAM) during walking in patients with symptomatic knee OA who were distinguished by different radiographic disease severities. Data from 137 symptomatic medial knee OA patients were used. Based on Kellgren/Lawrence (K/L) grading, the patients were divided into radiographically less severe (K/L ≤ 2, n=68) or severe (K/L>2, n=69) medial knee OA. Overall knee pain was rated on a 10 cm visual analog scale, and peak KAM and KAM impulses were obtained from gait analyses. Mixed linear regression analyses were performed with KAM variables as the outcome, and pain and disease severity as independent variables, adjusting for age, gender, and walking speed. In adjusted analyses, less severe patients demonstrated negative relationships between pain intensities and dynamic loading. The severe patient group showed no relationship between pain intensity and peak KAM, and a positive relationship between pain intensity and KAM impulse. In radiographically less severe knee OA, the negative relationships between pain intensity and dynamic knee joint loading indicate a natural reaction to pain, which will limit the stress on the joint. In contrast, either absent or positive relationships between pain and dynamic loading in severe OA may lead to overuse and accelerated disease progression. These findings may have a large potential interest for strategies of treatment in knee OA. Copyright © 2011 Elsevier B.V. All rights reserved.

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound.

PubMed

Cary, Theodore W; Reamer, Courtney B; Sultan, Laith R; Mohler, Emile R; Sehgal, Chandra M

2014-02-01

To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.

Is objectively measured sitting at work associated with low-back pain? A cross sectional study in the DPhacto cohort.

PubMed

Korshøj, Mette; Hallman, David M; Mathiassen, Svend Erik; Aadahl, Mette; Holtermann, Andreas; Jørgensen, Marie Birk

2018-01-01

Objectives Low-back pain (LBP) is a substantial health challenge due to the risk for long-term sickness absence and early retirement. Several biomechanical exposures at work, including sitting, have been suggested to increase the risk for LBP. The objectives of this study were to determine (i) the extent to which temporal patterns and total amount of objectively measured sitting is associated with LBP intensity and (ii) whether selected modifiers influence these associations. Methods This cross sectional study uses baseline data from the Danish PHysical ACTivity cohort with Objective measurements (DPhacto) of physical activities in the cleaning, transport and manufacturing sectors. Peak intensity of LBP was collected by questionnaire on a 0-10 scale and sitting was expressed in terms of total duration and temporal pattern, ie, time spent in brief bursts (≤5 minutes), moderate periods (>5-≤20 minutes), and prolonged periods of sitting (>20 minutes); both during work and whole day (waking hours only). Associations were determined using linear regression in models accounting for moderation and confounding. Factors evaluated as moderators or confounders were assessed by questionnaire. Results The population consisted of 704 participants. No significant associations were found between total duration or temporal patterns of sitting and LBP intensity, neither during work nor for the whole day. Body mass index (BMI) significantly moderated the association between sitting and LBP; participants with a high and low BMI showing a negative and positive association, respectively. Conclusion Sitting was not independently associated with peak LBP intensity, suggesting other exposures are more powerful risk factors for LBP.

Observation of Z decays to four leptons with the CMS detector at the LHC

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

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

The first observation of the Z boson decaying to four leptons in proton-proton collisions is presented. The analyzed data set corresponds to an integrated luminosity of 5.02 inverse femtobarns at sqrt(s) = 7 TeV collected by the CMS detector at the Large Hadron Collider. A pronounced resonance peak, with a statistical significance of 9.7 sigma, is observed in the distribution of the invariant mass of four leptons (electrons and/or muons) with mass and width consistent with expectations for Z boson decays. The branching fraction and cross section reported here are defined by phase space restrictions on the leptons, namely, 80more » < m[4l] < 100 GeV, where m[4l] is the invariant mass of the four leptons, and m[ll] > 4 GeV for all pairs of leptons, where m[ll] is the two-lepton invariant mass. The measured branching fraction is B(Z to 4l) = (4.2 /+0.9/-0.8 (stat.) +/- 0.2 (syst.)) 10E-6 and agrees with the standard model prediction of 4.45 10E-6. The measured cross section times branching fraction is sigma(pp to Z) B(Z to 4 l) = 112 +23/-20 (stat.) +7/-5 (syst.) +3/-2 (lumi.) fb, also consistent with the standard model prediction of 120 fb. The four-lepton mass peak arising from Z to 4 l decays provides a calibration channel for the Higgs boson search in the H to ZZ to 4 l decay mode.« less

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

PubMed Central

Cary, Theodore W.; Reamer, Courtney B.; Sultan, Laith R.; Mohler, Emile R.; Sehgal, Chandra M.

2014-01-01

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging. PMID:24506648

On mass and momentum conservation in the variable-parameter Muskingum method

NASA Astrophysics Data System (ADS)

Reggiani, Paolo; Todini, Ezio; Meißner, Dennis

2016-12-01

In this paper we investigate mass and momentum conservation in one-dimensional routing models. To this end we formulate the conservation equations for a finite-dimensional reach and compute individual terms using three standard Saint-Venant (SV) solvers: SOBEK, HEC-RAS and MIKE11. We also employ two different variable-parameter Muskingum (VPM) formulations: the classical Muskingum-Cunge (MC) and the revised, mass-conservative Muskingum-Cunge-Todini (MCT) approach, whereby geometrical cross sections are treated analytically in both cases. We initially compare the three SV solvers for a straight mild-sloping prismatic channel with geometric cross sections and a synthetic hydrograph as boundary conditions against the analytical MC and MCT solutions. The comparison is substantiated by the fact that in this flow regime the conditions for the parabolic equation model solved by MC and MCT are met. Through this intercomparison we show that all approaches have comparable mass and momentum conservation properties, except the MC. Then we extend the MCT to use natural cross sections for a real irregular river channel forced by an observed triple-peak event and compare the results with SOBEK. The model intercomparison demonstrates that the VPM in the form of MCT can be a computationally efficient, fully mass and momentum conservative approach and therefore constitutes a valid alternative to Saint-Venant based flood wave routing for a wide variety of rivers and channels in the world when downstream boundary conditions or hydraulic structures are non-influential.

Food neophobia and its association with diet quality and weight in children aged 24 months: a cross sectional study.

PubMed

Perry, Rebecca A; Mallan, Kimberley M; Koo, Jasly; Mauch, Chelsea E; Daniels, Lynne A; Magarey, Anthea M

2015-02-13

Food neophobia, the rejection of unknown or novel foods, may result in poor dietary patterns. This study investigates the cross-sectional relationship between neophobia in children aged 24 months and variety of fruit and vegetable consumption, intake of discretionary foods and weight. Secondary analysis of data from 330 parents of children enrolled in the NOURISH RCT (control group only) and SAIDI studies was performed using data collected at child age 24 months. Neophobia was measured at 24 months using the Child Food Neophobia Scale (CFNS). The cross-sectional associations between total CFNS score and fruit and vegetable variety, discretionary food intake and BMI (Body Mass Index) Z-score were examined via multiple regression models; adjusting for significant covariates. At 24 months, more neophobic children were found to have lower variety of fruits (β = -0.16, p = 0.003) and vegetables (β = -0.29, p < 0.001) but have a greater proportion of daily energy from discretionary foods (β = 0.11, p = 0.04). There was no significant association between BMI Z-score and CFNS score. Neophobia is associated with poorer dietary quality. Results highlight the need for interventions to (1) begin early to expose children to a wide variety of nutritious foods before neophobia peaks and (2) enable health professionals to educate parents on strategies to overcome neophobia.

Transcranial current stimulation focality using disc and ring electrode configurations: FEM analysis

NASA Astrophysics Data System (ADS)

Datta, Abhishek; Elwassif, Maged; Battaglia, Fortunato; Bikson, Marom

2008-06-01

We calculated the electric fields induced in the brain during transcranial current stimulation (TCS) using a finite-element concentric spheres human head model. A range of disc electrode configurations were simulated: (1) distant-bipolar; (2) adjacent-bipolar; (3) tripolar; and three ring designs, (4) belt, (5) concentric ring, and (6) double concentric ring. We compared the focality of each configuration targeting cortical structures oriented normal to the surface ('surface-radial' and 'cross-section radial'), cortical structures oriented along the brain surface ('surface-tangential' and 'cross-section tangential') and non-oriented cortical surface structures ('surface-magnitude' and 'cross-section magnitude'). For surface-radial fields, we further considered the 'polarity' of modulation (e.g. superficial cortical neuron soma hyper/depolarizing). The distant-bipolar configuration, which is comparable with commonly used TCS protocols, resulted in diffuse (un-focal) modulation with bi-directional radial modulation under each electrode and tangential modulation between electrodes. Increasing the proximity of the two electrodes (adjacent-bipolar electrode configuration) increased focality, at the cost of more surface current. At similar electrode distances, the tripolar-electrodes configuration produced comparable peak focality, but reduced radial bi-directionality. The concentric-ring configuration resulted in the highest spatial focality and uni-directional radial modulation, at the expense of increased total surface current. Changing ring dimensions, or use of two concentric rings, allow titration of this balance. The concentric-ring design may thus provide an optimized configuration for targeted modulation of superficial cortical neurons.

Analysis Techniques to Measure Charged Current Inclusive Water Cross Section and to Constrain Neutrino Oscillation Parameters using the Near Detector (ND280) of the T2K Experiment

NASA Astrophysics Data System (ADS)

Das, Rajarshi

2014-03-01

The Tokai to Kamioka (T2K) Experiment is a long-baseline neutrino oscillation experiment located in Japan with the primary goal to precisely measure multiple neutrino flavor oscillation parameters. An off-axis muon neutrino beam with an energy that peaks at 600 MeV is generated at the JPARC facility and directed towards the kiloton Super-Kamiokande (SK) water Cherenkov detector located 295 km away. The rates of electron neutrino and muon neutrino interactions are measured at SK and compared with expected model values. This yields a measurement of the neutrino oscillation parameters sinq and sinq. Measurements from a Near Detector that is 280 m downstream of the neutrino beam target are used to constrain uncertainties in the beam flux prediction and neutrino interaction rates. We present a measurement of inclusive charged current neutrino interactions on water. We used several sub-detectors in the ND280 complex, including a Pi-Zero detector (P0D) that has alternating planes of plastic scintillator and water bag layers, a time projection chamber (TPC) and fine-grained detector (FGD) to detect and reconstruct muons from neutrino charged current events. Finally, we describe a ``forward-fitting'' technique that is used to constrain the beam flux and cross section as an input for the neutrino oscillation analysis and also to extract a flux-averaged inclusive charged current cross section on water.

Dipole response of neutron-rich Sn isotopes

NASA Astrophysics Data System (ADS)

Klimkiewicz, A.; Adrich, P.; Boretzky, K.; Fallot, M.; Aumann, T.; Cortina-Gil, D.; Datta Pramanik, U.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellstroem, M.; Jones, K. L.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Nociforo, C.; Palit, R.; Simon, H.; Surowka, G.; Sümmerer, K.; Typel, S.; Walus, W.

2007-05-01

The neutron-rich isotopes 129-133Sn were studied in a Coulomb excitation experiment at about 500 AMeV using the FRS-LAND setup at GSI. From the exclusive measurement of all projectile-like particles following the excitation and decay of the projectile in a high-Z target, the energy differential cross section can be extracted. At these beam energies dipole transitions are dominating, and within the semi-classical approach the Coulomb excitation cross sections can be transformed into photoabsorption cross sections. In contrast to stable Sn nuclei, a substantial fraction of dipole strength is observed at energies below the giant dipole resonance (GDR). For 130Sn and 132Sn this strength is located in a peak-like structure around 10 MeV excitation energy and exhibits a few percent of the Thomas-Reiche Kuhn (TRK) sum-rule strength. Several calculations predict the appearance of dipole strength at low excitation energies in neutron-rich nuclei. This low-lying strength is often referred to as pygmy dipole resonance (PDR) and, in a macroscopic picture, is discussed in terms of a collective oscillation of excess neutrons versus the core nucleons. Moreover, a sharp rise is observed at the neutron separation threshold around 5 MeV for the odd isotopes. A possible contribution of 'threshold strength', which can be described within the direct-breakup model is discussed. The results for the neutron-rich Sn isotopes are confronted with results on stable nuclei investigated in experiments using real photons.

Spin and model determination of Z‧ - boson in lepton pair production at CERN LHC

NASA Astrophysics Data System (ADS)

Tsytrinov, A. V.; Pankov, A. A.; Serenkova, I. A.; Bednyakov, V. A.

2017-12-01

Many new physics models predict production of heavy resonances in Drell-Yan channel and can be observed at the CERN LHC. If a new resonance is discovered as a peak in the dilepton invariant mass distribution at the LHC, the identification of its spin and couplings can be done by measuring production rates and angular distributions of the decay products. Here we discuss the spin-1 identification of Z‧-boson for a set of representative models (SSM, E6, LR, and ALR) against the spin-2 RS graviton resonance and a spin-0 sneutrino resonance with the same mass and producing the same number of events under the resonance peak. We use the center-edge asymmetry for spin identification, as well as the total dilepton production cross section for the distinguishing the considered Z‧-boson models from one another.

Electrical cable utilization for wave energy converters

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

Bull, Diana; Baca, Michael; Schenkman, Benjamin

Here, this paper investigates the suitability of sizing the electrical export cable based on the rating of the contributing WECs within a farm. These investigations have produced a new methodology to evaluate the probabilities associated with peak power values on an annual basis. It has been shown that the peaks in pneumatic power production will follow an exponential probability function for a linear model. A methodology to combine all the individual probability functions into an annual view has been demonstrated on pneumatic power production by a Backward Bent Duct Buoy (BBDB). These investigations have also resulted in a highly simplifiedmore » and perfunctory model of installed cable cost as a function of voltage and conductor cross-section. This work solidifies the need to determine electrical export cable rating based on expected energy delivery as opposed to device rating as small decreases in energy delivery can result in cost savings.« less

Electrical cable utilization for wave energy converters

DOE PAGES

Bull, Diana; Baca, Michael; Schenkman, Benjamin

2018-04-27

Here, this paper investigates the suitability of sizing the electrical export cable based on the rating of the contributing WECs within a farm. These investigations have produced a new methodology to evaluate the probabilities associated with peak power values on an annual basis. It has been shown that the peaks in pneumatic power production will follow an exponential probability function for a linear model. A methodology to combine all the individual probability functions into an annual view has been demonstrated on pneumatic power production by a Backward Bent Duct Buoy (BBDB). These investigations have also resulted in a highly simplifiedmore » and perfunctory model of installed cable cost as a function of voltage and conductor cross-section. This work solidifies the need to determine electrical export cable rating based on expected energy delivery as opposed to device rating as small decreases in energy delivery can result in cost savings.« less

Role of partial linear momentum transfer on incomplete fusion reaction

NASA Astrophysics Data System (ADS)

Ali, Sabir; Ahmad, Tauseef; Kumar, Kamal; Gull, Muntazir; Rizvi, I. A.; Agarwal, Avinash; Ghugre, S. S.; Sinha, A. K.; Chaubey, A. K.

2018-04-01

Measurements of forward recoil range distributions (FRRDs) of the evaporation residues, populated in the 20Ne+51V reaction at E_{lab}≈ 145 MeV, have been carried out using the offline characteristic γ-ray detection method. The observation does corroborate the presence of complete fusion (CF) process in the population of p xn channel residues and both complete as well as incomplete fusion (ICF) processes in the population of α emitting channel residues. The FRRDs of p xn channel residues comprise single peak only, whereas α emitting channel residues have multiple peaks in their FRRDs. CF cross section data were used to extract the fusion functions. Extracted fusion functions were found to be suppressed with respect to the universal fusion function which is used as a uniform standard reference. The observed contribution arising from the ICF process in the population of α emitting channel residues is explained in terms of breakup fusion model.

Simplified Numerical Description of SPT Operations

NASA Technical Reports Server (NTRS)

Manzella, David H.

1995-01-01

A simplified numerical model of the plasma discharge within the SPT-100 stationary plasma thruster was developed to aid in understanding thruster operation. A one dimensional description was used. Non-axial velocities were neglected except for the azimuthal electron velocity. A nominal operating condition of 4.5 mg/s of xenon anode flow was considered with 4.5 Amperes of discharge current, and a peak radial magnetic field strength of 130 Gauss. For these conditions, the calculated results indicated ionization fractions of 0.99 near the thruster exit with a potential drop across the discharge of approximately 250 Volts. Peak calculated electron temperatures were found to be sensitive to the choice of total ionization cross section for ionization of atomic xenon by electron bombardment and ranged from 51 eV to 60 eV. The calculated ionization fraction, potential drop, and electron number density agree favorably with previous experiments. Calculated electron temperatures are higher than previously measured.

Electron-positron pair production by ultrarelativistic electrons in a soft photon field

NASA Technical Reports Server (NTRS)

Mastichiadis, A.; Marscher, A. P.; Brecher, K.

1986-01-01

The fully differential cross section for photon-electron pair production is integrated numerically over phase space. Results are obtained for the astrophysically interesting case in which the interaction between an ultrarelativistic electron and a soft photon results in electron-positron pair production. The positron spectrum is a function of the energies of both the photon and the electron, as well as the angle of interaction. It is found that the energy at which the positron distribution peaks is inversely proportional to the photon energy and independent of the electron energy. The positron spectrum is integrated once more over initial electron energies for a power-law energy distribution of primary electrons. The same procedure is repeated for the recoil particle; it is shown that the peak of the recoil energy distribution depends linearly on the energy of the primary electron. Finally, semianalytical expressions are obtained for the energy losses of the primary electrons.

Application of transmission loss concept in the evaluation of an acoustic filter for liquid-borne transverse resonance modes in a duct of circular cross section

NASA Technical Reports Server (NTRS)

Iwanicki, L. R.; Chang, Y. M.

1980-01-01

The transmission loss concept is used in the evaluation of an acoustic filter for liquid-borne transverse modes. Tests are conducted to determine the nature of filter element designs required to suppress transverse modes, to verify the presence of transverse modes in the test assembly, to define the acoustic wave incident, and to establish data recording, processing and analysis techniques providing transmission wave filter data. The first, second, and third tangential modes, and the first radial mode are found at frequencies of 2150, 3330, 4420, and 4110 Hz, respectively, and peaks of the tangential modes recede while the radial mode peak remains, demonstrating agreement with theoretical nodal patterns. The present design is found applicable to a liquid-oxygen system, and allows the easy-to-fabricate filter to fit within the available space envelope.

Synthesis and luminescence properties of KSrPO4:Eu2+ phosphor for radiation dosimetry

NASA Astrophysics Data System (ADS)

Palan, C. B.; Bajaj, N. S.; Omanwar, S. K.

2016-05-01

The KSrPO4:Eu phosphor was synthesized via solid state method. The structural and morphological characterizations were done through XRD (X-ray diffraction) and SEM (Scanning Electronic Microscope). Additionally, the photoluminescence (PL), thermoluminescence (TL) and optically Stimulated luminescence (OSL) properties of powder KSrPO4:Eu were studied. The PL spectra show blue emission under near UV excitation. It was advocated that KSrPO4:Eu phosphor not only show OSL sensitivity (0.47 times) but also gives faster decay in OSL signals than that of Al2O3:C (BARC) phosphor. The TL glow curve consist of two shoulder peaks and the kinetics parameters such as activation energy and frequency factors were determined by using peak shape method and also photoionization cross-sections of prepared phosphor was calculated. The radiation dosimetry properties such as minimum detectable dose (MDD), dose response and reusability were reported.

The Rise and Fall of Depressive Symptoms and Academic Stress in Two Samples of University Students.

PubMed

Barker, Erin T; Howard, Andrea L; Villemaire-Krajden, Rosanne; Galambos, Nancy L

2018-06-01

Self-reported depressive experiences are common among university students. However, most studies assessing depression in university students are cross-sectional, limiting our understanding of when in the academic year risk for depression is greatest and when interventions may be most needed. We examined within-person change in depressive symptoms from September to April. Study 1 (N = 198; 57% female; 72% white; Mage = 18.4): Depressive symptoms rose from September, peaked in December, and fell across the second semester. The rise in depressive symptoms was associated with higher perceived stress in December. Study 2 (N = 267; 78.7% female; 67.87% white; Mage = 21.25): Depressive symptoms peaked in December and covaried within persons with perceived stress and academic demands. The results have implications for understanding when and for whom there is increased risk for depressive experiences among university students.

Effect of the third π ∗ resonance on the angular distributions for electron-pyrimidine scattering

NASA Astrophysics Data System (ADS)

Mašín, Zdeněk; Gorfinkiel, Jimena D.

2016-07-01

We present a detailed analysis of the effect of the well known third π∗ resonance on the angular behaviour of the elastic cross section in electron scattering from pyrimidine. This resonance, occurring approximately at 4.7 eV, is of mixed shape and core-excited character. Experimental and theoretical results show the presence of a peak/dip behaviour in this energy range, that is absent for other resonances. Our investigations show that the cause of the peak/dip is an interference of background p-wave to p-wave scattering amplitudes with the amplitudes for resonant scattering. The equivalent resonance in pyrazine shows the same behaviour and the effect is therefore likely to appear in other benzene-like molecules. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

Prediction of Cardiorespiratory Fitness by the Six-Minute Step Test and Its Association with Muscle Strength and Power in Sedentary Obese and Lean Young Women: A Cross-Sectional Study

PubMed Central

Bonjorno Junior, José Carlos; de Oliveira, Cláudio Ricardo; Luporini, Rafael Luís; Mendes, Renata Gonçalves; Zangrando, Katiany Thais Lopes; Trimer, Renata; Arena, Ross

2015-01-01

Impaired cardiorespiratory fitness (CRF) is a hallmark characteristic in obese and lean sedentary young women. Peak oxygen consumption (VO2peak) prediction from the six-minute step test (6MST) has not been established for sedentary females. It is recognized that lower-limb muscle strength and power play a key role during functional activities. The aim of this study was to investigate cardiorespiratory responses during the 6MST and CPX and to develop a predictive equation to estimate VO2peak in both lean and obese subjects. Additionally we aim to investigate how muscle function impacts functional performance. Lean (LN = 13) and obese (OB = 18) women, aged 20–45, underwent a CPX, two 6MSTs, and isokinetic and isometric knee extensor strength and power evaluations. Regression analysis assessed the ability to predict VO2peak from the 6MST, age and body mass index (BMI). CPX and 6MST main outcomes were compared between LN and OB and correlated with strength and power variables. CRF, functional capacity, and muscle strength and power were lower in the OB compared to LN (<0.05). During the 6MST, LN and OB reached ~90% of predicted maximal heart rate and ~80% of the VO2peak obtained during CPX. BMI, age and number of step cycles (NSC) explained 83% of the total variance in VO2peak. Moderate to strong correlations between VO2peak at CPX and VO2peak at 6MST (r = 0.86), VO2peak at CPX and NSC (r = 0.80), as well as between VO2peak, NSC and muscle strength and power variables were found (p<0.05). These findings indicate the 6MST, BMI and age accurately predict VO2peak in both lean and obese young sedentary women. Muscle strength and power were related to measures of aerobic and functional performance. PMID:26717568

Method and apparatus for ion mobility spectrometry with alignment of dipole direction (IMS-ADD)

DOEpatents

Shvartsburg, Alexandre A [Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

2007-01-30

Techniques and instrumentation are described for analyses of substances, including complex samples/mixtures that require separation prior to characterization of individual components. A method is disclosed for separation of ion mixtures and identification of ions, including protein and other macromolecular ions and their different structural isomers. Analyte ions are not free to rotate during the separation, but are substantially oriented with respect to the drift direction. Alignment is achieved by applying, at a particular angle to the drift field, a much stronger alternating electric field that "locks" the ion dipoles with moments exceeding a certain value. That value depends on the buffer gas composition, pressure, and temperature, but may be as low as .about.3 Debye under certain conditions. The presently disclosed method measures the direction-specific cross-sections that provide the structural information complementing that obtained from known methods, and, when coupled to those methods, increases the total peak capacity and specificity of gas-phase separations. Simultaneous 2-D separations by direction-specific cross sections along and orthogonally to the ion dipole direction are also possible.

Dual-wavelength and efficient continuous-wave operation of a Yb:CaGd0.1Y0.9AlO4 laser

NASA Astrophysics Data System (ADS)

Di, J. Q.; Sai, Q. L.; Sun, X. H.; Xu, X. D.; Kong, L. C.; Xie, G. Q.; Liu, Y. L.; Teng, F.; Zhu, L.

2018-05-01

The spectra and laser properties of single crystalline Yb:CaGd0.1Y0.9AlO4 were investigated for the first time. The peak absorption cross-sections of 4.01 cm2 and 1.39  ×  10‑20 cm2 with full width at half maximum of 17 and 32 nm, and the maximum emission cross-sections of 2.11 and 1.53  ×  10‑20 cm2 were obtained for π and σ polarizations, respectively. The fluorescence decay time was 638 µs. The maximum continuous-wave laser achieved was 1.60 W with a slope efficiency of 23.4% for an a-cut Yb:CaGd0.1Y0.9AlO4 crystal. Dual-wavelength lasers at 1041.7 and 1044.9 nm were also demonstrated. The results show that Yb:CaGd0.1Y0.9AlO4 crystal is a promising ultra-short and dual-wavelength laser medium.

Tailoring surface plasmon resonance and dipole cavity plasmon modes of scattering cross section spectra on the single solid-gold/gold-shell nanorod

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

Chou Chau, Yuan-Fong, E-mail: chou.fong@ubd.edu.bn; Lim, Chee Ming; Kumara, N. T. R. N.

Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviorsmore » are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.« less

Velocity distributions of hydrogen atoms and hydroxyl radicals produced through solar photodissociation of water

NASA Astrophysics Data System (ADS)

Wu, C. Y. R.; Chen, F. Z.

1993-04-01

The velocity distributions of H and OH fragments produced through solar photodissociation of gaseous H2O molecules under collisionless conditions are presented. The calculations are carried out using: the most recently available absolute partial cross sections for the production of H and OH through photodissociation of H2O from its absorption onset at 1860 A down to 500 A; the newly available vibrational and rotational energy distributions of both the excited and ground state OH photofragments; the calculated cross sections for the total dissociation processes; and the integrated solar flux in 10 A increments from 500 to 1860 A in the continuum regions and the specific wavelength and flux at the bright solar lines. The calculated results show that the H atoms and the OH radicals produced exhibit multiple velocity groups. Since most current cometary modeling uses a single velocity of 20 km/sec associated with the photodissociation of H2O, the present results may be useful in interpreting the many peaks observed in the velocity distributions of the H Lyman alpha and H alpha of comets.

Photoproduction of hidden-charm states in the reaction near threshold

NASA Astrophysics Data System (ADS)

Huang, Yin; Xie, Ju-Jun; He, Jun; Chen, Xurong; Zhang, Hong-Fei

2016-12-01

We report on a theoretical study of the hidden charm states in the reaction near threshold within an effective Lagrangian approach. In addition to the contributions from the s-channel nucleon pole, the t-channel D0 exchange, the u-channel exchange and the contact term, we study the contributions from the states with spin-parity JP = 1/2- and 3/2-. The total and differential cross sections of the reaction are predicted. It is found that the contributions of these states give clear peak structures in the total cross sections. Thus, this reaction is another new platform to study the hidden-charm states. It is expected that our model calculation may be tested by future experiments. Supported by Major State Basic Research Development Program in China (2014CB845400), National Natural Science Foundation of China (11475227, 11275235, 11035006) and Chinese Academy of Sciences (Knowledge Innovation Project (KJCX2-EW-N01), Youth Innovation Promotion Association CAS (2016367), Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF151CJ1)

Raman spectroscopy and atomic force microscopy study of interfacial polytypism in GaP/Ge(111) heterostructures

NASA Astrophysics Data System (ADS)

Aggarwal, R.; Ingale, Alka A.; Dixit, V. K.

2018-01-01

Effects of lattice and polar/nonpolar mismatch between the GaP layer and Ge(111) substrate are investigated by spatially resolved Raman spectroscopy. The red shifted transverse optical (TO) and longitudinal optical (LO) phonons due to residual strain, along with asymmetry to TO phonon ∼358 cm-1 are observed in GaP/Ge(111). The peak intensity variation of mode ∼358 cm-1 with respect to TO phonon across the crystallographic morphed surface of GaP micro structures is associated with the topographical variations using atomic force microscopy mapping and Raman spectroscopy performed on both in plane and cross-sectional surface. Co-existence of GaP allotropes, i.e. wurtzite phase near heterojunction interface and dominant zinc-blende phase near surface is established using the spatially resolved polarized Raman spectroscopy from the cross sectional surface of heterostructures. This consistently explains effect of surface morphology on Raman spectroscopy from GaP(111). The study shows the way to identify crystalline phases in other advanced semiconductor heterostructures without any specific sample preparation.

Neutrino-nucleus reactions based on recent structure studies

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

Suzuki, Toshio; National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588

2015-05-15

Neutrino-nucleus reactions are studied with the use of new shell model Hamiltonians, which have proper tensor components in the interactions and prove to be successful in the description of Gamow-Teller (GT) strengths in nuclei. The new Hamiltonians are applied to obtain new neutrino-nucleus reaction cross sections in {sup 12}C, {sup 13}C, {sup 56}Fe and {sup 56}Ni induced by solar and supernova neutrinos. The element synthesis by neutrino processes in supernova explosions is discussed with the new cross sections. The enhancement of the production yields of {sup 7}Li, {sup 11}B and {sup 55}Mn is obtained while fragmented GT strength in {supmore » 56}Ni with two-peak structure is found to result in smaller e-capture rates at stellar environments. The monopole-based universal interaction with tensor force of π+ρ meson exchanges is used to evaluate GT strength in {sup 40}Ar and ν-induced reactions on {sup 40}Ar. It is found to reproduce well the experimental GT strength in {sup 40}Ar.« less

Partial-wave analysis for positronium-xenon collisions in the ultralow-energy region

NASA Astrophysics Data System (ADS)

Shibuya, Kengo; Saito, Haruo

2018-05-01

We propose a method to convert measured positronium annihilation rates in gaseous xenon into total and differential cross sections of positronium-xenon collisions in an ultralow-energy region of less than 80 meV where their experimental determinations as functions of the positronium kinetic energy are extremely difficult. This method makes it possible to determine not only the s -wave collisional parameters but also the p -wave and d -wave parameters. We have found a small positive value of the scattering length, A0=2.06 ±0.10 a0 , which indicates that the positronium-xenon interaction in this energy region is repulsive and suggests that it is dominated by the scattering amplitude of the positron rather than that of the electron. An extrapolation of the analytical result into the experimentally inaccessible energy regions from 80 meV to 1.0 eV indicates that there should not be a Ramsauer-Townsend minimum but rather a peak in the total cross section at an energy of approximately 0.4 eV.

Er{sup 3+}-doped strontium lithium bismuth borate glasses for broadband 1.5 {mu}m emission - optical properties

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

Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C.

2013-02-05

Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er{sup 3+} were prepared using conventional melt quench technique and investigated their optical properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra at room temperature. Judd-Ofelt (J-O) theory has been applied for the f.f transitions of Er{sup 3+} ions to evaluate J-O intensity parameters, {Omega}{lambda} ({lambda} = 2, 4 and 6). Using the J-O intensity parameters, radiative properties such as transition probabilities (A{sub R}), branching ratios ({beta})more » and radiative lifetimes ({tau}) are estimated for certain transitions. From the emission spectra, peak emission-cross sections ({sigma}{sub p}) and products of stimulated emission cross-section and full width at half maximum ({sigma}{sub p} Multiplication-Sign FWHM) were calculated for the observed emission transition, {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}.« less

Tailoring surface plasmon resonance and dipole cavity plasmon modes of scattering cross section spectra on the single solid-gold/gold-shell nanorod

NASA Astrophysics Data System (ADS)

Chou Chau, Yuan-Fong; Lim, Chee Ming; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Chiang, Hai-Pang

2016-09-01

Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.

Neutron-Induced Partial Cross-Section Measurements on ^76Ge Motivated by The Majorana Project 0νββ Decay Search

NASA Astrophysics Data System (ADS)

Hilderbrand, S.; Kwan, E.; Angell, C.; Fallin, B.; Howell, C. R.; Hutcheson, A.; Karwowski, H. J.; Kelley, J. H.; Tonchev, A. P.; Tornow, W.; Masters, D. B.; Pedroni, R. S.; Weisel, G. J.

2007-10-01

The goal of the Majorana Collaboration is to study 0νββ in order to verify that the neutrino is its own anti-particle; and if so, what is the mass ofthe electron neutrino. Observation of a sharp peak at the ββ endpoint energy will confirm 0νββ as a decay mode, and determination of the partial width will determine the matrix element which depends directly on the electron neutrino mass. In order to observe and verify the existence of 0νββ, it is important to reduce intrinsic, extrinsic,& cosmogenic backgrounds. The Majorana Project will operate with HPGe detectors deep underground to achieve a low-background environment. Recent advances in signal processing and detector design have also enabled scientists to further understand background sources. γ-ray spectra from the interaction of pulsed mono-energetic neutrons with ^76Ge were measured at TUNL using segmented HPGe clover detectors. The neutron-induced partial cross-sections for γ transitions in ^76Ge were measured at En = 8 and 12MeV.

27 CFR 9.140 - Atlas Peak.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Atlas Peak. 9.140 Section... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.140 Atlas Peak. (a) Name. The name of the viticultural area described in this section is “Atlas Peak.” (b...

Magnetic field studies of the solar wind interaction with venus from the galileo flyby.

PubMed

Kivelson, M G; Kennel, C F; McPherron, R L; Russell, C T; Southwood, D J; Walker, R J; Hammond, C M; Khurana, K K; Strangeway, R J; Coleman, P J

1991-09-27

During the 10 February 1990 flyby of Venus, the Galileo spacecraft skimmed the downstream flank of the planetary bow shock. This provided an opportunity to examine both the global and the local structure of the shock in an interval during which conditions in the solar wind plasma were quite steady. The data show that the cross section of the shock in planes transverse to the flow is smaller in directions aligned with the projection of the interplanetary magnetic field than in directions not so aligned. Ultralow-frequency waves were present in the unshocked solar wind, and their amplitude peaked when the spacecraft was downstream of the foreshock. At large distances down the tail, the Mach number of the flow normal to the shock is low, thus providing the opportunity to study repeated crossings of the collisionless shock in an interesting parameter regime. Some of the shock crossings reveal structure that comes close to the theoretically predicted form of intermediate shocks, whose existence in collisionless plasmas has not been confirmed.

Magnetic field studies of the solar wind interaction with Venus from the Galileo flyby

NASA Technical Reports Server (NTRS)

Kivelson, M. G.; Kennel, C. F.; Mcpherron, R. L.; Russell, C. T.; Southwood, D. J.; Walker, R. J.; Hammond, C. M.; Khurana, K. K.; Strangeway, R. J.; Coleman, P. J.

1991-01-01

During the February 10, 1990 flyby of Venus, the Galileo spacecraft skimmed the downnstream flank of the planetary bow shock. This provided an opportunity to examine both the global and the local structure of the shock in an interval during which conditions in the solar wind plasma were quite steady. The data show that the cross section of the shock in planes transverse to the flow is smaller in directions aligned with the projection of the interplanetary magnetic field than in directions not so aligned. Ultralow-frequency waves were present in the unshocked solar wind, and their amplitude peaked when the spacecraft was downstream of the foreshock. At large distances down the tail, the Mach number of the flow normal to the shock is low, thus providing the opportunity to study repeated crossings of the collisionless shock in an interesting parameter regime. Some of the shock crossings reveal structure that comes close to the theoretically predicted form of intermediate shocks, whose existence in collisionless plasmas has not been confirmed.

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry.

PubMed

Dodds, James N; May, Jody C; McLean, John A

2017-11-21

Here we examine the relationship among resolving power (R p ), resolution (R pp ), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based resolving power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak resolving power suggested. When a CCS-based R p definition was utilized, TWIMS was found to operate at a resolving power between 40 and 50, confirming the previous observations by Giles and co-workers. After the separation axis (and corresponding resolving power) is converted to cross section space, it is possible to effectively predict separation behavior for all mobility techniques evaluated (i.e., uniform field, trapped ion mobility, traveling wave, cyclic, and overtone instruments) using the equations described in this work. Finally, we are able to establish for the first time that the current state-of-the-art ion mobility separations benchmark at a CCS-based resolving power of >300 that is sufficient to differentiate analyte ions with CCS differences as small as 0.5%.

Greater association of peak neuromuscular performance with cortical bone geometry, bone mass and bone strength than bone density: A study in 417 older women.

PubMed

Belavý, Daniel L; Armbrecht, Gabriele; Blenk, Tilo; Bock, Oliver; Börst, Hendrikje; Kocakaya, Emine; Luhn, Franziska; Rantalainen, Timo; Rawer, Rainer; Tomasius, Frederike; Willnecker, Johannes; Felsenberg, Dieter

2016-02-01

We evaluated which aspects of neuromuscular performance are associated with bone mass, density, strength and geometry. 417 women aged 60-94years were examined. Countermovement jump, sit-to-stand test, grip strength, forearm and calf muscle cross-sectional area, areal bone mineral content and density (aBMC and aBMD) at the hip and lumbar spine via dual X-ray absorptiometry, and measures of volumetric vBMC and vBMD, bone geometry and section modulus at 4% and 66% of radius length and 4%, 38% and 66% of tibia length via peripheral quantitative computed tomography were performed. The first principal component of the neuromuscular variables was calculated to generate a summary neuromuscular variable. Percentage of total variance in bone parameters explained by the neuromuscular parameters was calculated. Step-wise regression was also performed. At all pQCT bone sites (radius, ulna, tibia, fibula), a greater percentage of total variance in measures of bone mass, cortical geometry and/or bone strength was explained by peak neuromuscular performance than for vBMD. Sit-to-stand performance did not relate strongly to bone parameters. No obvious differential in the explanatory power of neuromuscular performance was seen for DXA aBMC versus aBMD. In step-wise regression, bone mass, cortical morphology, and/or strength remained significant in relation to the first principal component of the neuromuscular variables. In no case was vBMD positively related to neuromuscular performance in the final step-wise regression models. Peak neuromuscular performance has a stronger relationship with leg and forearm bone mass and cortical geometry as well as proximal forearm section modulus than with vBMD. Copyright © 2015 Elsevier Inc. All rights reserved.

Explaining the DAMPE data with scalar dark matter and gauged U(1)_{L_e-L_μ } interaction

NASA Astrophysics Data System (ADS)

Cao, Junjie; Feng, Lei; Guo, Xiaofei; Shang, Liangliang; Wang, Fei; Wu, Peiwen; Zu, Lei

2018-03-01

Inspired by the peak structure observed by recent DAMPE experiment in e^+e^- cosmic-ray spectrum, we consider a scalar dark matter (DM) model with gauged U(1)_{L_e-L_μ } symmetry, which is the most economical anomaly-free theory to potentially explain the peak by DM annihilation in nearby subhalo. We utilize the process χ χ → Z^' Z^' → l \\bar{l} l^' \\bar{l}^' , where χ , Z^' , l^{(' )} denote the scalar DM, the new gauge boson and l^{(' )} =e, μ , respectively, to generate the e^+e^- spectrum. By fitting the predicted spectrum to the experimental data, we obtain the favored DM mass range m_χ ˜eq 3060^{+80}_{-100} GeV and Δ m ≡ m_χ - m_{Z^' } ≲ 14 GeV at 68% Confidence Level (C.L.). Furthermore, we determine the parameter space of the model which can explain the peak and meanwhile satisfy the constraints from DM relic abundance, DM direct detection and the collider bounds. We conclude that the model we consider can account for the peak, although there exists a tension with the constraints from the LEP-II bound on m_{Z^' } arising from the cross section measurement of e^+e^- → Z^' *} → e^+ e^-.

Correlation between Maxillary Canine Calcification and Skeletal Maturation.

PubMed

Kumar, Sushil; Roy, Abhishek Singha; Garg, Ankit; Hamid, Saeed Bin; Tyagi, Sumit; Kumar, Atish

2017-05-01

Skeletal maturation assessment has a great role in many health professions especially in Orthodontics & Dentofacial Orthopedics. Functional appliances have proved to be more effective when used at the peak of mandibular growth, rather than before. The aim of this study was to evaluate whether the calcification stages of permanent maxillary canine are useful to assess skeletal maturity. In this cross-sectional study, samples were derived from panoramic radiographs and lateral cephalograms of 300 subjects (137 males and 163 females) with their age ranging from 9 to 18 years. Dental maturity {Demirjian Index (DI)} and skeletal maturity {Cervical Stages (CS)} were assessed from radiographs. The Pearson chi-square test (χ 2 ) and Sakoda adjusted Pearson contingency coefficient (C*) were calculated to determine the correlation between DI and CS. A highly significant association (C* = 0.851, p <.001for males and 0.879, p <.001 for females) was found between DI and CS. DI stage E coincided with CS2 (pre-peak of pubertal growth spurt) & DI stage F coincided with CS3 (peak of pubertal growth spurt) for all the subjects. DI stage H corresponded to CS5 and CS6 (end of peak of pubertal growth spurt). A highly significant association was found between DI and CS. Maxillary canine DI stages could be useful to assess skeletal maturity.

Oxford Grading Scale vs manometer for assessment of pelvic floor strength in nulliparous sports students.

PubMed

Da Roza, T; Mascarenhas, T; Araujo, M; Trindade, V; Jorge, R Natal

2013-09-01

To compare pelvic floor muscle strength in nulliparous sports students measured using the modified Oxford Grading Scale and a Peritron manometer; and to compare the manometric measurements between continent and incontinent subjects. Cross-sectional study. All subjects were evaluated twice on the same day; first by vaginal digital examination and subsequently by vaginal pressure using a Peritron manometer. Forty-three nulliparous female sports students [mean age 21 (standard deviation 4) years] from the Sports Faculty of the University of Porto. This study found a significant moderate correlation between the Oxford Grading Scale score and peak pressure on manometry (r=0.646, P=0.002). Mean maximal strength for the entire group was 70.4cmH2O (range 21 to 115cmH2O). Out of 43 subjects, 37% (n=16) demonstrated signs of incontinence. On manometry, no significant differences were found in vaginal resting pressure or peak pressure between the continent and incontinent groups. There was moderate correlation between peak pressure on manometry and the Oxford Grading Scale score. Peritron manometer measurements of pelvic floor muscle contractions showed no significant differences in vaginal resting pressure and peak pressure in continent and incontinent subjects. Copyright © 2012 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Application of energy derivative method to determine the structural components' contribution to deceleration in crashes.

PubMed

Nagasaka, Kei; Mizuno, Koji; Thomson, Robert

2018-03-26

For occupant protection, it is important to understand how a car's deceleration time history in crashes can be designed using efficient of energy absorption by a car body's structure. In a previous paper, the authors proposed an energy derivative method to determine each structural component's contribution to the longitudinal deceleration of a car passenger compartment in crashes. In this study, this method was extended to 2 dimensions in order to analyze various crash test conditions. The contribution of each structure estimated from the energy derivative method was compared to that from a conventional finite element (FE) analysis method using cross-sectional forces. A 2-dimensional energy derivative method was established. A simple FE model with a structural column connected to a rigid body was used to confirm the validity of this method and to compare with the result of cross-sectional forces determined using conventional analysis. Applying this method to a full-width frontal impact simulation of a car FE model, the contribution and the cross-sectional forces of the front rails were compared. In addition, this method was applied to a pedestrian headform FE simulation in order to determine the influence of the structural and inertia forces of the hood structures on the deceleration of the headform undergoing planar motion. In an oblique impact of the simple column and rigid body model, the sum of the contributions of each part agrees with the rigid body deceleration, which indicates the validity of the 2-dimensional energy derivative method. Using the energy derivative method, it was observed that each part of the column contributes to the deceleration of the rigid body by collapsing in the sequence from front to rear, whereas the cross-sectional force at the rear of the column cannot detect the continuous collapse. In the full-width impact of a car, the contributions of the front rails estimated in the energy derivative method was smaller than that using the cross-sectional forces at the rear end of the front rails due to the deformation of the passenger compartment. For a pedestrian headform impact, the inertial and structural forces of the hood contributed to peaks of the headform deceleration in the initial and latter phases, respectively. Using the 2-dimensional energy derivative method, it is possible to analyze an oblique impact or a pedestrian headform impact with large rotations. This method has advantages compared to the conventional approach using cross-sectional forces because the contribution of each component to system deceleration can be determined.

Environmental Assessment and Finding of No Significant Impact: Curecanti-Lost Canyon 230-kV Transmission Line Reroute Project, Montrose County, Colorado

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

N /A

2000-03-20

The Department of Energy (DOE), Western Area Power Administration (Western) is proposing to reroute a section of the Curecanti-Lost Canyon 230-kilovolt (kV) transmission line, in Montrose County, Colorado. A portion of the transmission line, situated 11 miles southeast of Montrose, Colorado, crosses Waterdog Peak, an area of significant geologic surface activity, which is causing the transmission line's lattice steel towers to shift. This increases stress to structure hardware and conductors, and poses a threat to the integrity of the transmission system. Western proposes to relocate the lattice steel towers and line to a more geologically stable area. The existing sectionmore » of transmission line and the proposed relocation route cross Bureau of Land Management and private land holdings.« less

Intraabdominal pressure in women during CrossFit exercises and the effect of age and parity.

PubMed

Gephart, Laura Faye; Doersch, Karen M; Reyes, Michelle; Kuehl, Thomas J; Danford, Jill M

2018-07-01

To determine intraabdominal pressure (IAP) in women during CrossFit and to determine whether parity, age, or CrossFit experience affects IAP during CrossFit exercises, we evaluated 10 women: 5 experienced and active CrossFitters and 5 who were not regularly engaged in CrossFit. A Laborie urodynamics abdominal pressure probe with the Goby wireless system measured IAP during 10 repetitions of 13 different CrossFit exercises. Women had a mean age of 36 years. A significant difference was found between mean peak IAP of the 5 parous vs the 5 nulliparous women ( P = 0.009). Experience with CrossFit did not affect mean peak IAP achieved with exercise. In some exercises, there was a significant change in IAP as participants progressed through repetitions ( P = 0.003 for back squats and 0.04 for sit-ups). Participants achieved IAP values that were markedly higher than those previously published.

Electron collisions with methyl-substituted ethylenes: Cross section measurements and calculations for 2-methyl–2-butene and 2,3-dimethyl–2-butene

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

Szmytkowski, Czesław, E-mail: czsz@mif.pg.gda.pl; Stefanowska, Sylwia; Zawadzki, Mateusz

We report electron-scattering cross sections determined for 2-methyl–2-butene [(H{sub 3}C)HC = C(CH{sub 3}){sub 2}] and 2,3-dimethyl–2-butene [(H{sub 3}C){sub 2}C = C(CH{sub 3}){sub 2}] molecules. Absolute grand-total cross sections (TCSs) were measured for incident electron energies in the 0.5–300 eV range, using a linear electron-transmission technique. The experimental TCS energy dependences for the both targets appear to be very similar with respect to the shape. In each TCS curve, three features are discernible: the resonant-like structure located around 2.6–2.7 eV, the broad distinct enhancement peaking near 8.5 eV, and a weak hump in the vicinity of 24 eV. Theoretical integral elasticmore » (ECS) and ionization (ICS) cross sections were computed up to 3 keV by means of the additivity rule (AR) approximation and the binary-encounter-Bethe method, respectively. Their sums, (ECS+ICS), are in a reasonable agreement with the respective measured TCSs. To examine the effect of methylation of hydrogen sides in the ethylene [H{sub 2}C = CH{sub 2}] molecule on the TCS, we compared the TCS energy curves for the sequence of methylated ethylenes: propene [H{sub 2}C = CH(CH{sub 3})], 2-methylpropene [H{sub 2}C = C(CH{sub 3}){sub 2}], 2-methyl–2-butene [(H{sub 3}C)HC = C(CH{sub 3}){sub 2}], and 2,3-dimethyl–2-butene [(H{sub 3}C){sub 2}C = C(CH{sub 3}){sub 2}], measured in the same laboratory. Moreover, the isomeric effect is also discussed for the C{sub 5}H{sub 10} and C{sub 6}H{sub 12} compounds.« less

Long bone robustness during growth: A cross-sectional pQCT examination of children and young adults aged 5-29years.

PubMed

Rantalainen, Timo; Weeks, Benjamin K; Nogueira, Rossana C; Beck, Belinda R

2016-12-01

Skeletal robustness (cross-section size relative to length) is associated with stress fractures in adults, and appears to explain the high incidence of distal radius fractures in adolescents. However, little is known about the ontogeny of long bone robustness during the first three decades of life. Therefore, we explored the ontogeny of tibial, fibular, ulnar and radial robustness in a cross-sectional sample of 5 to 29year-old volunteers of both sexes. Peripheral quantitative computed tomography (pQCT) was used to evaluate cross-sections of the leg (4%, 14%, 38% and 66%), and forearm (4%, and 66%) in N=432 individuals. Robustness was evaluated as the total bone area divided by bone length. Differences between age-groups, sexes, and age-group×sex interactions were evaluated with ANOVA with Tukey's post hocs where appropriate. Most bone sites exhibited more robust bones in men than women (P<0.001 to 0.02), and in older age-groups than younger (P<0.001). Sex×age-group interaction was observed at the 66% and 38% tibia sites with robustness increasing more with age in men than in women (P=0.006 to 0.042). Post-hoc analyses indicated no sex differences prior to 13years-of-age, and notable exceptions to increasing robustness with age at the 4% radial and 66% tibial sites, which exhibited reduced robustness in age groups close to peak height velocity. In conclusion, the present results suggest that very little sexual dimorphism in long bone robustness exists prior to puberty, and that divergence occurs primarily after cessation of longitudinal growth. A period of relative diaphyseal slenderness was identified at age-groups coinciding with the adolescent growth spurt, which may be related to the relatively high incidence of frank and stress fracture in adolescents. Copyright © 2016 Elsevier Inc. All rights reserved.

Improved reference standards for femtosecond three-photon excitation of fluorescence in the wavelength range 950 - 1750 nm

NASA Astrophysics Data System (ADS)

Rebane, Aleksander; Mikhaylov, Alexander

2018-02-01

Fluorescence excited by instantaneous three-photon absorption (3PA) in organic fluorophores is gaining importance as a versatile modality for deep-tissue microscopy and imaging. However, due to technical difficulty of quantifying the higher-order nonlinear absorption cross-section, reliable 3PA cross section values, σ3PA, covering a broad spectral range have been so far not available. This lack of experimental data hinders us from gaining quantitative understanding of relevant structure-property relationships as well as impedes progress towards developing 3-photon fluorophores optimized for various applications. We report on measurement of the absolute 3PA cross section spectra in the 950 - 1750 nm range in a series of common organic fluorophores in various solvents: (a) Rhodamine 6G in deuterated methanol, (b) Coumarin 153 in DMSO and toluene, (c) Prodan in DMSO and toluene, (d) Fluorescein in pH11 buffer, (e) AF455 in toluene, (f) BDPAS in deuterated methylene chloride. In these experiments, we employ femtosecond wavelength-tunable optical parametric amplifier to excite fluorescence signal that has cubic dependence on the incident photon flux. Absolute values of σ3PA are determined using two complementary methods: (i) calibrating the fluorescence signal relative to one-photon (linear) excitation combined with accurate measurement of the pulse temporal- and spatial profile to determine the excitation photon flux and (ii) calibration of the cubic fluorescence signal relative to quadratic florescence excited in fluorophores with known two-photon absorption cross section. Depending on the method utilized, the peak σ3PA values have estimated accuracy 50% and vary in the range, σ3PA = 10-81 - 10-79 cm6 s2 photon-2 , depending on the system studied, with AF455 showing the most enhanced 3PA efficiency. The 3PA spectral shapes have estimated accuracy of 20% and show some unexpected deviations from corresponding one-photon spectral profiles.

Study of correlation between maternal fatigue and uterine contraction pattern in the active phase of labour.

PubMed

Ebrahimzadeh, Samira; Golmakani, Nahid; Kabirian, Maryam; Shakeri, Mohhamad T

2012-06-01

To evaluate the correlation between maternal fatigue and uterine contraction pattern at the beginning of the active phase of labour. Fatigue is one of the most common complaints in pregnant women that often continues until delivery. Maternal fatigue prolongs the labour process and increases the rate of cesarian section. Studies on the pattern of uterine contractions have shown that the length of the fall time is longer in prolonged labours than in normal deliveries. A cross-sectional study. This study was conducted on 100 primiparous women who were referred to Ommolbanin Hospital (Mashhad, Iran) in 2011. Maternal fatigue was assessed at the beginning of the active phase of labour. Then, the pattern of uterine contractions was monitored for 30 minutes by an external tocodynamometer. The F/R ratio was determined by measuring the time for a contraction to return to its baseline from its peak and the time for a contraction to rise to its peak. The data were analysed by chi-square and anova tests. The results showed that there was a significant relationship between maternal fatigue and uterine contraction pattern. The F/R ratio was increased with increase in fatigue severity. Fatigue causes changes in the pattern of uterine contractions. The return time of a contraction from its peak to its baseline (fall) is increased with increase in fatigue severity. Offering strategies to prevent tiredness and reduce the related fatigue complications. © 2012 Blackwell Publishing Ltd.

EUV/soft x-ray spectra for low B neutron stars

NASA Technical Reports Server (NTRS)

Romani, Roger W.; Rajagopal, Mohan; Rogers, Forrest J.; Iglesias, Carlos A.

1995-01-01

Recent ROSAT and EUVE detections of spin-powered neutron stars suggest that many emit 'thermal' radiation, peaking in the EUV/soft X-ray band. These data constrain the neutron stars' thermal history, but interpretation requires comparison with model atmosphere computations, since emergent spectra depend strongly on the surface composition and magnetic field. As recent opacity computations show substantial change to absorption cross sections at neutron star photospheric conditions, we report here on new model atmosphere computations employing such data. The results are compared with magnetic atmosphere models and applied to PSR J0437-4715, a low field neutron star.

Electron Raman scattering in a strained ZnO/MgZnO double quantum well

NASA Astrophysics Data System (ADS)

Mojab-abpardeh, M.; Karimi, M. J.

2018-02-01

In this work, the electron Raman scattering in a strained ZnO / MgZnO double quantum wells is studied. The energy eigenvalues and the wave functions are obtained using the transfer matrix method. The effects of Mg composition, well width and barrier width on the internal electric field in well and barrier layers are investigated. Then, the influences of these parameters on the differential cross-section of electron Raman scattering are studied. Results indicate that the position, magnitude and the number of the peaks depend on the Mg composition, well width and barrier width.

Resonant inelastic x-ray scattering on iso-C₂H₂Cl₂ around the chlorine K-edge: structural and dynamical aspects.

PubMed

Kawerk, Elie; Carniato, Stéphane; Journel, Loïc; Marchenko, Tatiana; Piancastelli, Maria Novella; Žitnik, Matjaž; Bučar, Klemen; Bohnic, Rok; Kavčič, Matjaž; Céolin, Denis; Khoury, Antonio; Simon, Marc

2014-10-14

We report a theoretical and experimental study of the high resolution resonant K(α) X-ray emission lines around the chlorine K-edge in gas phase 1,1-dichloroethylene. With the help of ab initio electronic structure calculations and cross section evaluation, we interpret the lowest lying peak in the X-ray absorption and emission spectra. The behavior of the K(α) emission lines with respect to frequency detuning highlights the existence of femtosecond nuclear dynamics on the dissociative Potential Energy Surface of the first K-shell core-excited state.

Resonant inelastic x-ray scattering on iso-C2H2Cl2 around the chlorine K-edge: Structural and dynamical aspects

NASA Astrophysics Data System (ADS)

Kawerk, Elie; Carniato, Stéphane; Journel, Loïc; Marchenko, Tatiana; Piancastelli, Maria Novella; Žitnik, Matjaž; Bučar, Klemen; Bohnic, Rok; Kavčič, Matjaž; Céolin, Denis; Khoury, Antonio; Simon, Marc

2014-10-01

We report a theoretical and experimental study of the high resolution resonant Kα X-ray emission lines around the chlorine K-edge in gas phase 1,1-dichloroethylene. With the help of ab initio electronic structure calculations and cross section evaluation, we interpret the lowest lying peak in the X-ray absorption and emission spectra. The behavior of the Kα emission lines with respect to frequency detuning highlights the existence of femtosecond nuclear dynamics on the dissociative Potential Energy Surface of the first K-shell core-excited state.

Flood profiles for lower Brooker Creek, west-central Florida

USGS Publications Warehouse

Murphy, W.R.

1978-01-01

Flood heights are computed for a range of recurrence intervals for a 12.6 mile reach of Brooker Creek, beginning at the mouth at Lake Tarpon. A Geological Survey step-backwater computer program, E431, was used in these analyses using: (1) Stream and valley cross-section geometry and roughness data; (2) Recurrence interval flood-peak discharges; (3) Recurrence interval starting elevations; (4) Gaging station stage-discharge relations. Flood heights may be plotted versus distance above stream mouth and connected to construct flood profiles. They may also be used to indicate areas of inundation on detailed topographic maps.

A laser system to remotely sense bird movements

NASA Technical Reports Server (NTRS)

Korschgen, C. E.; Green, W. L.; Seasholtz, R. G.

1983-01-01

The design and operation of a laser detection system for migrating birds are presented. A battery-powered class-III laser (operating at 904 nm, pulse-repetition rate 5 kHz, pulse duration 100 nsec, and peak power 25 W) and a photodiode receiver are mounted on poles at height 10 m and distance 850 m and equipped with 135-mm f/2.8 collimating lenses; beam diameter at the receiver is 1.7 m. The microprocessor-controlled system is found to detect the passing of an object as small as 30 sq cm in cross section at a distance of 425 m.

Adaptation of rat jaw muscle fibers in postnatal development with a different food consistency: an immunohistochemical and electromyographic study.

PubMed

Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Kinouchi, Nao; Kawakami, Emi; Tanne, Kazuo; Langenbach, Geerling E J; Tanaka, Eiji

2010-06-01

The development of the craniofacial system occurs, among other reasons, as a response to functional needs. In particular, the deficiency of the proper masticatory stimulus affects the growth. The purpose of this study was to relate alterations of muscle activity during postnatal development to adaptational changes in the muscle fibers. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a solid (hard-diet group) or a powder (soft-diet group) diet for 63 days. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time), the total burst number and their average length exceeding specified levels of the peak activity (5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of fibers by means of immunohistochemical staining and their cross-sectional area was measured. All muscle fibers were identified as slow type I and fast type IIA, IIX or IIB (respectively, with increasing twitch contraction speed and fatigability). At lower activity levels (exceeding 5% of the peak activity), the duty time of the anterior belly of the digastric muscle was significantly higher in the soft-diet group than in the hard-diet group (P < 0.05). At higher activity levels (exceeding 20 and 50% of the peak activity), the duty time of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.05). There was no difference in the duty time of the anterior temporalis muscle at any muscle activity level. The percentage of type IIA fibers of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.01) and the opposite was true with regard to type IIB fibers (P < 0.05). The cross-sectional area of type IIX and type IIB fibers of the superficial masseter muscle was significantly smaller in the soft-diet group than in the hard-diet group (P < 0.05). There was no difference in the muscle fiber composition and the cross-sectional area of the anterior belly of the digastric and anterior temporalis muscles. In conclusion, for the jaw muscles of male rats reared on a soft diet, the slow-to-fast transition of muscle fiber was shown in only the superficial masseter muscle. Therefore, the reduction in the amount of powerful muscle contractions could be important for the slow-to-fast transition of the myosin heavy chain isoform in muscle fibers.

Inelastic neutron scattering cross sections for Ge 76 relevant to background in neutrinoless double- β decay experiments

DOE PAGES

Crider, B. P.; Peters, E. E.; Allmond, J. M.; ...

2015-09-11

The experimental signature in searches for the neutrinoless double- decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Moreover, inelastic scattering reactions with neutrons from muon-induced interactions and ( ,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We also measured the production cross sections for rays from the 76Ge(n,n ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the crossmore » sections of a previously known 2040.7-keV ray from the 3952-keV level in 76 Ge are rather small, we find that a larger contribution arises from a 2037.5-keV ray which is attributed to a newly identified level at 3147 keV in 76Ge. Finally, a third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double- decay searches is more complex than was previously thought.« less

Correlated hydrogen bonding fluctuations and vibrational cross peaks in N-methyl acetamide: simulation based on a complete electrostatic density functional theory map.

PubMed

Hayashi, Tomoyuki; Mukamel, Shaul

2006-11-21

The coherent nonlinear response of the entire amide line shapes of N-methyl acetamide to three infrared pulses is simulated using an electrostatic density functional theory map. Positive and negative cross peaks contain signatures of correlations between the fundamentals and the combination state. The amide I-A and I-III cross-peak line shapes indicate positive correlation and anticorrelation of frequency fluctuations, respectively. These can be ascribed to correlated hydrogen bonding at C[double bond]O and N-H sites. The amide I frequency is negatively correlated with the hydrogen bond on carbonyl C[double bond]O, whereas the amide A and III are negatively and positively correlated, respectively, with the hydrogen bond on amide N-H.

Influence of post-stroke spasticity on EMG-force coupling and force steadiness in biceps brachii.

PubMed

Carlyle, Jennilee K; Mochizuki, George

2018-02-01

Individuals with spasticity after stroke experience a decrease in force steadiness which can impact function. Alterations in the strength of EMG-force coupling may contribute to the reduction in force steadiness observed in spasticity. The aim was to determine the extent to which force steadiness and EMG-force coupling is affected by post-stroke spasticity. This cross-sectional study involved individuals with upper limb spasticity after stroke. Participants were required to generate and maintain isometric contractions of the elbow flexors at varying force levels. Coefficient of variation of force, absolute force, EMG-force cross-correlation function peak and peak latency was measured from both limbs with surface electromyography and isometric dynamometry. Statistically significant differences were observed between the affected and less affected limbs for all outcome measures. Significant main effects of force level were also observed. Force steadiness was not statistically significantly correlated with EMG-force coupling; however, both force steadiness and absolute force were associated with the level of impairment as measured by the Chedoke McMaster Stroke Assessment Scale. Spasticity after stroke uncouples the relationship between EMG and force and is associated with reduced force steadiness during isometric contractions; however, these features of control are not associated in individuals with spasticity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure of collagen-glycosaminoglycan matrix and the influence to its integrity and stability.

PubMed

Bi, Yuying; Patra, Prabir; Faezipour, Miad

2014-01-01

Glycosaminoglycan (GAG) is a chain-like disaccharide that is linked to polypeptide core to connect two collagen fibrils/fibers and provide the intermolecular force in Collagen-GAG matrix (C-G matrix). Thus, the distribution of GAG in C-G matrix contributes to the integrity and mechanical properties of the matrix and related tissue. This paper analyzes the transverse isotropic distribution of GAG in C-G matrix. The angle of GAGs related to collagen fibrils is used as parameters to qualify the GAGs isotropic characteristic in both 3D and 2D rendering. Statistical results included that over one third of GAGs were perpendicular directed to collagen fibril with symmetrical distribution for both 3D matrix and 2D plane cross through collagen fibrils. The three factors tested in this paper: collagen radius, collagen distribution, and GAGs density, were not statistically significant for the strength of Collagen-GAG matrix in 3D rendering. However in 2D rendering, a significant factor found was the radius of collagen in matrix for the GAGs directed to orthogonal plane of Collagen-GAG matrix. Between two cross-section selected from Collagen-GAG matrix model, the plane cross through collagen fibrils was symmetrically distributed but the total percentage of perpendicular directed GAG was deducted by decreasing collagen radius. There were some symmetry features of GAGs angle distribution in selected 2D plane that passed through space between collagen fibrils, but most models showed multiple peaks in GAGs angle distribution. With less GAGs directed to perpendicular of collagen fibril, strength in collagen cross-section weakened. Collagen distribution was also a factor that influences GAGs angle distribution in 2D rendering. True hexagonal collagen packaging is reported in this paper to have less strength at collagen cross-section compared to quasi-hexagonal collagen arrangement. In this work focus is on GAGs matrix within the collagen and its relevance to anisotropy.

Cardiorespiratory responses of a dance session designed for older women: A cross sectional study.

PubMed

Rodrigues-Krause, Josianne; Farinha, Juliano Boufleur; Ramis, Thiago Rozales; Boeno, Francesco Pinto; Dos Santos, Gabriela Cristina; Krause, Mauricio; Reischak-Oliveira, Alvaro

2018-06-04

Dancing has been increasingly used as a type of exercise intervention to improve cardiovascular fitness of older people. However, it is unclear which may be the exercise intensity of the dance sessions. To describe cardiorespiratory responses of a dance session for older women, and to identify intensity zones in relation to peak oxygen consumption (VO 2 peak), first and second ventilatory thresholds (VT1 and VT2). Ten women (66 ± 5 yrs., BMI 27 ± 4) were examined on three occasions: Familiarization, maximum effort and dance sessions. Incremental treadmill test: 5 km/h, 2% slope each min, until maximum effort. Dance class (60 min): warm-up (20 min), across-the-floor (10 min), choreography (15 min), show (10 min) and cool-down (5 min). Ventilatory parameters were measured continuously (breath-by-breath). VO 2 (mL·kg -1 ·min -1 ): Maximum effort: VO 2 peak (23.3 ± 4.3), VT1 (17.2 ± 3.5) and VT2 (20.9 ± 3.4). Dancing: warm-up (12.8 ± 2.4, ~55%VO 2 peak), across-the-floor (14.2 ± 2.4 ~62%VO 2 peak), choreography (14.6 ± 3.2 ~63%VO 2 peak) and show (16.1 ± 3.3, ~69% VO 2 peak). Show was similar to VT1. Cardiorespiratory demands of a dance class for older women are at low aerobic intensity. Show was similar to VT1, indicating that a dance class may be modulated to improve aerobic fitness, at least at initial stages of training. Copyright © 2018 Elsevier Inc. All rights reserved.

Pulmonary arterial pressure detects functional mitral stenosis after annuloplasty for primary mitral regurgitation: An exercise stress echocardiographic study.

PubMed

Samiei, Niloufar; Tajmirriahi, Marzieh; Rafati, Ali; Pasebani, Yeganeh; Rezaei, Yousef; Hosseini, Saeid

2018-02-01

The restrictive mitral valve annuloplasty (RMA) is the treatment of choice for degenerative mitral regurgitation (MR), but postoperative functional mitral stenosis remains a matter of debate. In this study, we sought to determine the impact of mitral stenosis on the functional capacity of patients. In a cross-sectional study, 32 patients with degenerative MR who underwent RMA using a complete ring were evaluated. All participants performed treadmill exercise test and underwent echocardiographic examinations before and after exercise. The patients' mean age was 50.1 ± 12.5 years. After a mean follow-up of 14.1 ± 5.9 months (6-32 months), the number of patients with a mitral valve peak gradient >7.5 mm Hg, a mitral valve mean gradient >3 mm Hg, and a pulmonary arterial pressure (PAP) ≥25 mm Hg at rest were 50%, 40.6%, and 62.5%, respectively. 13 patients (40.6%) had incomplete treadmill exercise test. All hemodynamic parameters were higher at peak exercise compared with at rest levels (all P < .05). The PAP at rest and at peak exercise as well as peak transmitral gradient at peak exercise were higher in patients with incomplete exercise compared with complete exercise test (all P < .05). The PAP at rest (a sensitivity and a specificity of 84.6% and 52.6%, respectively; area under the curve [AUC] = .755) and at peak exercise (a sensitivity and a specificity of 100% and 47.4%, respectively; AUC = .755) discriminated incomplete exercise test. The RMA for degenerative MR was associated with a functional stenosis and the PAP at rest and at peak exercise discriminated low exercise capacity. © 2017, Wiley Periodicals, Inc.

Dynamic balance control in elders: gait initiation assessment as a screening tool

NASA Technical Reports Server (NTRS)

Chang, H.; Krebs, D. E.; Wall, C. C. (Principal Investigator)

1999-01-01

OBJECTIVE: To determine whether measurements of center of gravity-center of pressure separation (CG-CP moment arm) during gait initiation can differentiate healthy from disabled subjects with sufficient specificity and sensitivity to be useful as a screening test for dynamic balance in elderly patients. SUBJECTS: Three groups of elderly subjects (age, 74.97+/-6.56 yrs): healthy elders (HE, n = 21), disabled elders (DE, n = 20), and elders with vestibular hypofunction (VH, n = 18). DESIGN: Cross-sectional, intact-groups research design. Peak CG-CP moment arm measures how far the subject will tolerate the whole-body CG to deviate from the ground reaction force's CP; it represents dynamic balance control. Screening test cutoff points at 16 to 18 cm peak CG-CP moment arm predicted group membership. RESULTS: The magnitude of peak CG-CP moment arm was significantly greater in HE than in DE and VH subjects (p<.01) and was not different between the DE and VH groups. The peak CG-CP moment arm occurred at the end of single stance phase in all groups. As a screening test, the peak moment arm has greater than 50% sensitivity and specificity to discriminate the HE group from the DE and VH groups with peak CG-CP moment arm cutoff points between 16 and 18 cm. CONCLUSIONS: Examining dynamic balance through the use of the CG-CP moment arm during single stance in gait initiation discriminates between nondisabled and disabled older persons and warrants further investigation as a potential tool to identify people with balance dysfunction.

Chapter 10: Peak Demand and Time-Differentiated Energy Savings Cross-Cutting Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

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

Kurnik, Charles W; Stern, Frank; Spencer, Justin

Savings from electric energy efficiency measures and programs are often expressed in terms of annual energy and presented as kilowatt-hours per year (kWh/year). However, for a full assessment of the value of these savings, it is usually necessary to consider the measure or program's impact on peak demand as well as time-differentiated energy savings. This cross-cutting protocol describes methods for estimating the peak demand and time-differentiated energy impacts of measures implemented through energy efficiency programs.

Non-destructive NIR spectral imaging assessment of bone water: Comparison to MRI measurements.

PubMed

Rajapakse, Chamith S; Padalkar, Mugdha V; Yang, Hee Jin; Ispiryan, Mikayel; Pleshko, Nancy

2017-10-01

Bone fracture risk increases with age, disease states, and with use of certain therapeutics, such as acid-suppressive drugs, steroids and high-dose bisphosphonates. Historically, investigations into factors that underlie bone fracture risk have focused on evaluation of bone mineral density (BMD). However, numerous studies have pointed to factors other than BMD that contribute to fragility, including changes in bone collagen and water. The goal of this study is to investigate the feasibility of using near infrared spectral imaging (NIRSI) to determine the spatial distribution and relative amount of water and organic components in whole cross-sections of bone, and to compare those results to those obtained using magnetic resonance imaging (MRI) methods. Cadaver human whole-section tibiae samples harvested from 18 donors of ages 27-97years underwent NIRSI and ultrashort echo time (UTE) MRI. As NIRSI data is comprised of broad absorbances, second derivative processing was evaluated as a means to narrow peaks and obtain compositional information. The (inverted) second derivative peak heights of the NIRSI absorbances correlated significantly with the mean peak integration of the water, collagen and fat NIR absorbances, respectively, indicating that either processing method could be used for compositional assessment. The 5797cm -1 absorbance was validated as arising from the fat present in bone marrow, as it completely disappeared after ultrasonication. The MRI UTE-determined bound water content in tibial cortical bone samples ranged from 62 to 91%. The NIRSI water peaks at 5152cm -1 and at 7008cm -1 correlated significantly with the UTE data, with r=0.735, p=0.016, and r=0.71, p=0.0096, respectively. There was also a strong correlation between the intensity of the NIRSI water peak at 7008cm -1 and the intensity of the collagen peak at 4608cm -1 (r=0.69, p=0.004). Since NIRSI requires minimal to no sample preparation, this approach has great potential to become a gold standard modality for the investigation of changes in water content, distribution, and environment in pre-clinical studies of bone pathology and therapeutics. Copyright © 2017 Elsevier Inc. All rights reserved.

Decreased peak arteriovenous oxygen difference during treadmill exercise testing in individuals infected with the human immunodeficiency virus.

PubMed

Cade, W Todd; Fantry, Lori E; Nabar, Sharmila R; Keyser, Randall E

2003-11-01

To determine if arteriovenous oxygen difference was lower in asymptomatic individuals with human immunodeficiency virus (HIV) infection than in sedentary but otherwise healthy controls. Quasi-experimental cross-sectional. Clinical exercise laboratory. Fifteen subjects (10 men, 5 women) with HIV and 15 healthy gender- and activity level-matched controls (total N=30). Participants performed an incremental maximal exercise treadmill test to exhaustion. Electrocardiogram, metabolic, and noninvasive cardiac output measurements were evaluated at rest and throughout the tests. Data were analyzed by using analysis of covariance. Peak oxygen consumption (Vo(2)), cardiac output, stroke volume, and arteriovenous oxygen difference. The arteriovenous oxygen difference was determined indirectly using the Fick equation. Peak VO(2) was significantly lower (P<.0005) in participants with HIV (24.6+/-1.2mL.kg(-1).min(-1)) compared with controls (32.0+/-1.2mL.kg(-1).min(-1)). There were no significant intergroup differences in cardiac output or stroke volume at peak exercise. Peak arteriovenous oxygen difference was significantly lower (P<.04) in those infected with HIV (10.8+/-0.5 volume %) than in controls (12.4+/-0.5 volume %). The observed deficit in aerobic capacity in the participants with HIV appeared to be the result of a peripheral tissue oxygen extraction or utilization limitation. In addition to deconditioning, potential mechanisms for this significant attenuation may include HIV infection and inflammation, highly active antiretroviral therapy medication regimens, or a combination of these factors.

The associations between quadriceps muscle strength, power, and knee joint mechanics in knee osteoarthritis: A cross-sectional study.

PubMed

Murray, Amanda M; Thomas, Abbey C; Armstrong, Charles W; Pietrosimone, Brian G; Tevald, Michael A

2015-12-01

Abnormal knee joint mechanics have been implicated in the pathogenesis and progression of knee osteoarthritis. Deficits in muscle function (i.e., strength and power) may contribute to abnormal knee joint loading. The associations between quadriceps strength, power and knee joint mechanics remain unclear in knee osteoarthritis. Three-dimensional motion analysis was used to collect peak knee joint angles and moments during the first 50% of stance phase of gait in 33 participants with knee osteoarthritis. Quadriceps strength and power were assessed using a knee extension machine. Strength was quantified as the one repetition maximum. Power was quantified as the peak power produced at 40-90% of the one repetition maximum. Quadriceps strength accounted for 15% of the variance in peak knee flexion angle (P=0.016). Quadriceps power accounted for 20-29% of the variance in peak knee flexion angle (P<0.05). Quadriceps power at 90% of one repetition maximum accounted for 9% of the variance in peak knee adduction moment (P=0.05). These data suggest that quadriceps power explains more variance in knee flexion angle and knee adduction moment during gait in knee osteoarthritis than quadriceps strength. Additionally, quadriceps power at multiple loads is associated with knee joint mechanics and therefore should be assessed at a variety of loads. Taken together, these results indicate that quadriceps power may be a potential target for interventions aimed at changing knee joint mechanics in knee osteoarthritis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of electric potential and current on mandibular linear measurements in cone beam CT.

PubMed

Panmekiate, S; Apinhasmit, W; Petersson, A

2012-10-01

The purpose of this study was to compare mandibular linear distances measured from cone beam CT (CBCT) images produced by different radiographic parameter settings (peak kilovoltage and milliampere value). 20 cadaver hemimandibles with edentulous ridges posterior to the mental foramen were embedded in clear resin blocks and scanned by a CBCT machine (CB MercuRay(TM); Hitachi Medico Technology Corp., Chiba-ken, Japan). The radiographic parameters comprised four peak kilovoltage settings (60 kVp, 80 kVp, 100 kVp and 120 kVp) and two milliampere settings (10 mA and 15 mA). A 102.4 mm field of view was chosen. Each hemimandible was scanned 8 times with 8 different parameter combinations resulting in 160 CBCT data sets. On the cross-sectional images, six linear distances were measured. To assess the intraobserver variation, the 160 data sets were remeasured after 2 weeks. The measurement precision was calculated using Dahlberg's formula. With the same peak kilovoltage, the measurements yielded by different milliampere values were compared using the paired t-test. With the same milliampere value, the measurements yielded by different peak kilovoltage were compared using analysis of variance. A significant difference was considered when p < 0.05. Measurement precision varied from 0.03 mm to 0.28 mm. No significant differences in the distances were found among the different radiographic parameter combinations. Based upon the specific machine in the present study, low peak kilovoltage and milliampere value might be used for linear measurements in the posterior mandible.

Effects of obstructive sleep apnea and obesity on exercise function in children.

PubMed

Evans, Carla A; Selvadurai, Hiran; Baur, Louise A; Waters, Karen A

2014-06-01

Evaluate the relative contributions of weight status and obstructive sleep apnea (OSA) to cardiopulmonary exercise responses in children. Prospective, cross-sectional study. Participants underwent anthropometric measurements, overnight polysomnography, spirometry, cardiopulmonary exercise function testing on a cycle ergometer, and cardiac doppler imaging. OSA was defined as ≥ 1 obstructive apnea or hypopnea per hour of sleep (OAHI). The effect of OSA on exercise function was evaluated after the parameters were corrected for body mass index (BMI) z-scores. Similarly, the effect of obesity on exercise function was examined when the variables were adjusted for OAHI. Tertiary pediatric hospital. Healthy weight and obese children, aged 7-12 y. N/A. Seventy-one children were studied. In comparison with weight-matched children without OSA, children with OSA had a lower cardiac output, stroke volume index, heart rate, and oxygen consumption (VO2 peak) at peak exercise capacity. After adjusting for BMI z-score, children with OSA had 1.5 L/min (95% confidence interval -2.3 to -0.6 L/min; P = 0.001) lower cardiac output at peak exercise capacity, but minute ventilation and ventilatory responses to exercise were not affected. Obesity was only associated with physical deconditioning. Cardiac dysfunction was associated with the frequency of respiratory-related arousals, the severity of hypoxia, and heart rate during sleep. Children with OSA are exercise limited due to a reduced cardiac output and VO2 peak at peak exercise capacity, independent of their weight status. Comorbid OSA can further decrease exercise performance in obese children.

Bion 11 Spaceflight Project: Effect of Weightlessness on Single Muscle Fiber Function in Rhesus Monkeys

NASA Technical Reports Server (NTRS)

Fitts, Robert H.; Romatowski, Janell G.; Widrick, Jeffrey J.; DeLaCruz, Lourdes

1999-01-01

Although it is well known that microgravity induces considerable limb muscle atrophy, little is known about how weightlessness alters cell function. In this study, we investigated how weightlessness altered the functional properties of single fast and slow striated muscle fibers. Physiological studies were carried out to test the hypothesis that microgravity causes fiber atrophy, a decreased peak force (Newtons), tension (Newtons/cross-sectional area) and power, an elevated peak rate of tension development (dp/dt), and an increased maximal shortening velocity (V(sub o)) in the slow type I fiber, while changes in the fast-twitch fiber are restricted to atrophy and a reduced peak force. For each fiber, we determined the peak force (P(sub o)), V(sub o), dp/dt, the force-velocity relationship, peak power, the power-force relationship, the force-pCa relationship, and fiber stiffness. Biochemical studies were carried out to assess the effects of weightlessness on the enzyme and substrate profile of the fast- and slow-twitch fibers. We predicted that microgravity would increase resting muscle glycogen and glycolytic metabolism in the slow fiber type, while the fast-twitch fiber enzyme profile would be unaltered. The increased muscle glycogen would in part result from an elevated hexokinase and glycogen synthase. The enzymes selected for study represent markers for mitochondrial function (citrate synthase and 0-hydroxyacyl-CoA dehydrogenase), glycolysis (Phosphofructokinase and lactate dehydrogenase), and fatty acid transport (Carnitine acetyl transferase). The substrates analyzed will include glycogen, lactate, adenosine triphosphate, and phosphocreatine.

Anthropogenic controls on geomorphic evolution of the Upper Missouri River

NASA Astrophysics Data System (ADS)

Benthem, A.; Skalak, K.; Schenk, E.; Hupp, C.; Galloway, J.; Nustad, R.

2012-12-01

The 70-mile free flowing Upper Missouri River reach is bounded upstream by the Garrison Dam and downstream by Lake Oahe. The Garrison Dam, which regulates flow into the reach, was completed in 1953; the Oahe Dam (which created Lake Oahe and the associated delta near Bismarck, ND) was completed in 1959. This reach is used for recreation, water supply, fisheries, and as habitat for threatened and endangered species. The Upper Missouri River regularly (approximately every two years) received annual peak flows above 100,000 cubic feet per second (cfs) prior to the completion of the Garrison Dam. Annual peak flows consistently have been between 30,000 and 45,000 cfs following dam completion. The largest flood since dam regulation occurred in 2011 following an abnormally high snow pack season and a week-long rain event in the headwaters. Flood releases from the Garrison Dam began in May 2011 and peaked in June with a flow of approximately 150,000 cfs. The peak flow was sustained for two weeks. The dam releases have had a discernible impact on the Missouri River throughout this section. The 2011 flood has highlighted the critical need for quantifying the complex interaction between the regional geomorphology and human activities. It is necessary to first understand and quantify the historical impacts of the dams in order to determine the impact of the 2011 flood on channel planform, morphology, and sediment dynamics. We have created a spatial-temporal conceptual model of the governing fluvial and deltaic processes for the reach. Methods used for the development of the conceptual model include interpretation of repeat aerial photography, historical streamgage data, historical cross-sectional surveys, in addition to ground-truthing data with sediment cores, channel surveys, and dendrogeomorphic tools. Preliminary results indicate that prior to the 2011 flood the reach had achieved a dynamic equilibrium in response to dam closure and subsequent managed flows. The perturbation from the dam closure attenuated over approximately a 30-year period. Cross-sectional analysis indicates the reach just below the Garrison Dam increased in capacity over this period and the lower end of the reach (just upstream of the delta) either maintained capacity or experienced a reduction. Analysis of channel planform through repeat aerial photography suggests channel adjustment of varying types and degrees. Loss of islands and erosion has occurred in the 20 miles just below the dam; the next 30 miles have generally remained metastable and many islands in the remaining 20 miles of the river have become bank-attached. Loss of conveyance and increased frequency and growth of islands has occurred in the delta above the reservoir. However, the Upper Missouri River is still responding to the historic flood of 2011 and analysis is ongoing.

CHANGES IN PATELLOFEMORAL JOINT STRESS DURING RUNNING WITH THE APPLICATION OF A PREFABRICATED FOOT ORTHOTIC.

PubMed

Almonroeder, Thomas G; Benson, Lauren C; O'Connor, Kristian M

2015-12-01

Foot orthotics are commonly utilized in the treatment of patellofemoral pain (PFP) and have shown clinical benefit; however, their mechanism of action remains unclear. Patellofemoral joint stress (PFJS) is thought to be one of the main etiological factors associated with PFP. The primary purpose of this study was to investigate the effects of a prefabricated foot orthotic with 5 ° of medial rearfoot wedging on the magnitude and the timing of the peak PFJS in a group of healthy female recreational athletes. The hypothesis was that there would be significant reduction in the peak patellofemoral joint stress and a delay in the timing of this peak in the orthotic condition. Cross-sectional. Kinematic and kinetic data were collected during running trials in a group of healthy, female recreational athletes. The knee angle and moment data in the sagittal plane were incorporated into a previously developed model to estimate patellofemoral joint stress. The dependent variables of interest were the peak patellofemoral joint stress as well as the percentage of stance at which this peak occurred, as both the magnitude and the timing of the joint loading are thought to be important in overuse running injuries. The peak patellofemoral joint stress significantly increased in the orthotic condition by 5.8% (p=.02, ES=0.24), which does not support the initial hypothesis. However, the orthotic did significantly delay the timing of the peak during the stance phase by 3.8% (p=.002, ES=0.47). The finding that the peak patellofemoral joint stress increased in the orthotic condition did not support the initial hypothesis. However, the finding that the timing of this peak was delayed to later in the stance phase in the orthotic condition did support the initial hypothesis and may be related to the clinical improvements previously reported in subjects with PFP. Level 4.

Comparison of standing postural control and gait parameters in people with and without chronic low back pain: a cross-sectional case-control study.

PubMed

MacRae, Catharine Siân; Critchley, Duncan; Lewis, Jeremy S; Shortland, Adam

2018-01-01

Differences in postural control and gait have been identified between people with and without chronic low back pain (CLBP); however, many previous studies present data from small samples, or have used methodologies with questionable reliability. This study, employing robust methodology, hypothesised that there would be a difference in postural control, and spatiotemporal parameters of gait in people with CLBP compared with asymptomatic individuals. This cross-sectional case-control study age-matched and gender-matched 16 CLBP and 16 asymptomatic participants. Participants were assessed barefoot (1) standing, over three 40 s trials, under four posture challenging conditions (2) during gait. Primary outcome was postural stability (assessed by root mean squared error of centre of pressure (CoP) displacement (CoP RMSEAP ) and mean CoP velocity (CoP VELAP ), both in the anteroposterior direction); gait outcomes were hip range of movement and peak moments, walking speed, cadence and stride length, assessed using force plates and a motion analysis system. There were no differences between groups in CoP RMSEAP (P=0.26), or CoP VELAP (P=0.60) for any standing condition. During gait, no differences were observed between groups for spatiotemporal parameters, maximum, minimum and total ranges of hip movement, or peak hip flexor or extensor moments in the sagittal plane. In contrast to previous research, this study suggests that people with mild to moderate CLBP present with similar standing postural control, and parameters of gait to asymptomatic individuals. Treatments directed at influencing postural stability (eg, standing on a wobble board) or specific parameters of gait may be an unnecessary addition to a treatment programme.

Dietary isoflavones and bone mineral density during midlife and the menopausal transition: cross-sectional and longitudinal results from the Study of Women's Health Across the Nation Phytoestrogen Study.

PubMed

Greendale, Gail A; Tseng, Chi-Hong; Han, Weijuan; Huang, Mei-Hua; Leung, Katherine; Crawford, Sybil; Gold, Ellen B; Waetjen, L Elaine; Karlamangla, Arun S

2015-03-01

This study aims to examine cross-sectional and longitudinal relations between dietary intake of isoflavones and bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN) in black, white, Chinese, and Japanese women during the menopausal transition. We tested whether tertiles of isoflavone intake were associated with baseline BMD when all women were premenopausal or early perimenopausal. To analyze whether isoflavone intake was associated with longitudinal BMD, we fitted piecewise linear models to repeated measurements of baseline-normalized LS or FN BMD as functions of time before or after the final menstrual period (FMP) date. Multiply adjusted mean FN BMD values of premenopausal Japanese women were monotonically positively related to isoflavone consumption (P for trend = 0.0003). Otherwise, no statistically significant baseline associations were observed. During the period of 1 year before the FMP through 5 years after the FMP, all participants lost LS and FN BMD. Loss was unrelated to isoflavone intake, except for Japanese women during the period of 1 year before the FMP to 2 years after the FMP: higher tertiles of isoflavone intake were associated with greater annual LS BMD loss rates (P for trend = 0.01) and FN loss rates (P for trend = 0.04). In Japanese women, higher isoflavone intake is associated with higher peak FN BMD but also with greater rates of LS and FN BMD loss during the menopausal transition. Results for the other racial/ethnic groups did not support a relation between dietary intake of isoflavones and either peak BMD or BMD loss during the menopausal transition.

Ground reaction forces and bone parameters in females with tibial stress fracture.

PubMed

Bennell, Kim; Crossley, Kay; Jayarajan, Jyotsna; Walton, Elizabeth; Warden, Stuart; Kiss, Z Stephen; Wrigley, Tim

2004-03-01

Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.

An hourglass model for the flare of HST-1 in M87

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

Liu, Wen-Po; Zhao, Guang-Yao; Chen, Yong Jun

To explain the multi-wavelength light curves (from radio to X-ray) of HST-1 in the M87 jet, we propose an hourglass model that is a modified two-zone system of Tavecchio and Ghisellini (hereafter TG08): a slow hourglass-shaped or Laval-nozzle-shaped layer connected by two revolving exponential surfaces surrounding a fast spine through which plasma blobs flow. Based on the conservation of magnetic flux, the magnetic field changes along the axis of the hourglass. We adopt the result of TG08—the high-energy emission from GeV to TeV can be produced through inverse Compton by the two-zone system, and the photons from radio to X-raymore » are mainly radiated by the fast inner zone system. Here, we only discuss the light curves of the fast inner blob from radio to X-ray. When a compressible blob travels down the axis of the first bulb in the hourglass, because of magnetic flux conservation, its cross section experiences an adiabatic compression process, which results in particle acceleration and the brightening of HST-1. When the blob moves into the second bulb of the hourglass, because of magnetic flux conservation, the dimming of the knot occurs along with an adiabatic expansion of its cross section. A similar broken exponential function could fit the TeV peaks in M87, which may imply a correlation between the TeV flares of M87 and the light curves from radio to X-ray in HST-1. The Very Large Array (VLA) 22 GHz radio light curve of HST-1 verifies our prediction based on the model fit to the main peak of the VLA 15 GHz radio one.« less

Partial tooth gear bearings

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2010-01-01

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Immunogenicity, biochemical and serological characterizations of ribosomal preparations from human oral strains of serotypes c and d of the bacterium Streptococcus mutans.

PubMed

Huis in 't Veld, J; Fischer, M

1984-01-01

Crude ribosomal preparations of Streptococcus mutans C67-1 (serotype c) and 50B4 (serotype d) contain protein RNA and carbohydrate. Sepharose CL-2B column chromatography of preparations yielded two distinct peaks. Cell-wall carbohydrates were predominantly present in peak I; the serological activity resided mainly in peak II. The preparations contained antigens which cross-reacted with several streptococcal Lancefield antisera. Antisera prepared against the preparations cross-reacted with cell-wall proteins (NaCl extracts) and Ag I/II, but not with cell-wall carbohydrate antigens (Rantz-Randall extracts). Thus, cell-envelope protein antigens in the preparations appear to be responsible for the serological activity. The unique properties of ribosomal preparations may, apart from serological cross-reactivity, be useful in the immunological protection against dental caries.

Measurement of the Number of Light Neutrino Generations, Z Resonance Parameters, and Absolute Luminosity at the Aleph Detector

NASA Astrophysics Data System (ADS)

Wear, James A.

Measurements of the production cross section sigma (e^+e^-to Z to hadrons) have been made with the ALEPH detector in a seven-point energy scan across the Z resonance at the LEP e^+e^ - collider. The selection of hadronic Z decays is performed with a systematic uncertainty of 0.3%, resulting in 147,836 events. The absolute luminosity has been determined with a systematic uncertainty of 0.9%. These hadronic cross sections and ALEPH's measurement of Z decay into charged leptons, sigma(e^+e^ -to Z to l^+l^ -), are used in fits to extract parameters of the Z resonance in a model-independent way. The Z mass and total width are measured to be M_{Z } = 91.177 +/- 0.010 _{exp} +/- 0.020_{LEP} GeV and Gamma_{Z} = 2.482 +/- 0.018_{exp} +/- 0.006_{LEP } GeV where the second errors are due to LEP beam energy uncertainties. The Z decay partial widths are measured to be Gamma_{h} = 1.738 +/- 0.016 GeV, Gamma_{l} = 83.45 +/- 0.76 MeV, and Gamma_ {inv} = 0.493 +/- 0.015 GeV. The Born-level peak hadronic cross section is sigma_sp{had}{0 } = 41.58 +/- 0.44 nb, R = Gamma_{h }/Gamma_{l} = 20.83 +/- 0.21, and Gamma_{inv}/Gamma _{l} = 5.91 +/- 0.18. The number of light neutrino generations is determined to be N_{nu} = 2.96 +/- 0.09 and the Standard Model electroweak mixing angle to be sin^2 theta_{W} = 0.2325 +/- 0.0027.

Collision cross section (CCS) measurement by ion cyclotron resonance mass spectrometry with short-time Fourier transform.

PubMed

Hu, Miao; Zhang, Linzhou; He, Shan; Xu, Chunming; Shi, Quan

2018-05-15

The collision cross section (CCS) is an important shape parameter which is often used in molecular structure investigation. In Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), the CCS affects the ion signal damping shape due to the effect of ion-neutral collisions. It is potential to obtain ion CCS values from FTICR-MS with the help of a proper ion-collision model. We have developed a rapid method to obtain the ion damping profile and CCS for mixtures by only one FTICR-MS measurement. The method utilizes short-time Fourier transform (STFT) to process FTICR-MS time domain signals. The STFT-processed result is a three-dimensional (3D) spectrum which has an additional time axis in addition to the conventional mass-to-charge ratio and intensity domains. The damping profile of each ion can be recognized from the 3D spectrum. After extracting the decay profile of a specified ion, all the three ion-neutral collision models were tested in curve fitting. The hard-sphere model was proven to be suitable for our experimental setup. A linear relationship was observed between the CCS value and hard-sphere model parameters. Therefore, the CCS values of all the peaks were obtained through the addition of internal model compounds and linear calibration. The proposed method was successfully applied to determine the CCSs of fatty acids and polyalanines in a petroleum gas oil matrix. This technique can be used for simultaneous measurement of cross sections for many ions in congested spectra. Copyright © 2018 John Wiley & Sons, Ltd.

Viking Lander image analysis of Martian atmospheric dust

NASA Technical Reports Server (NTRS)

Pollack, James B.; Ockert-Bell, Maureen E.; Shepard, Michael K.

1995-01-01

We have reanalyzed three sets of Viking Lander 1 and 2 (VL1 and VL2) images of the Martian atmosphere to better evaluate the radiative properties of the atmospheric dust particles. The properties of interest are the first two moments of the size distribution, the single-scattering albedo, the dust single-scattering phase function, and the imaginary index of refraction. These properties provide a good definition of the influence that the atmospheric dust has on heating of the atmosphere. Our analysis represents a significant improvement over past analyses (Pollack et al. 1977, 1979) by deriving more accurate brightness closer to the sun, by carrying out more precise analyses of the data to acquire the quantities of interest, and by using a better representation of scattering by nonspherical particles. The improvements allow us to better define the diffraction peak and hence the size distribution of the particles. For a lognormal particle size distribution, the first two moments of the size distribution, weighted by the geometric cross section, are found. The geometric cross-section weighted mean radius r(sub eff) is found to be 1.85 +/- 0.3 micrometers at VL2 during northern summer when dust loading was low and 1.52 +/- 0.3 micrometers at VL1 during the first dust storm. In both cases the best cross-section weighted mean variance nu(sub eff) of the size distribution is equal to 0.5 +/- 0.2 micrometers. The changes in size distribution, and thus radiative properties, do not represent a substantial change in solar energy deposition in the atmosphere over the Pollak et al. (1977, 1979) estimates.

Viking Lander image analysis of Martian atmospheric dust

NASA Technical Reports Server (NTRS)

Pollack, James B.; Ockert-Bell, Maureen E.; Shepard, Michael K.

1995-01-01

We have reanalyzed three sets of Viking Lander 1 and 2 (VL1 and VL2) images of the Martian atmosphere to better evaluate the radiative properties of the atmospheric dust particles. The properties of interest are the first two moments of the size distribution, the single-scattering albedo, the dust single-scattering phase function, and the imaginary index of refraction. These properties provide a good definition of the influence that the atmospheric dust has on heating of the atmosphere. Our analysis represents a significant improvement over past analyses (Pollack et al. 1977,1979) by deriving more accurate brightnesses closer to the sun, by carrying out more precise analyses of the data to acquire the quantities of interest, and by using a better representation of scattering by nonspherical particles. The improvements allow us to better define the diffraction peak and hence the size distribution of the particles. For a lognormal particle size distribution, the first two moments of the size distribution, weighted by the geometric cross section, are found. The geometric cross-section weighted mean radius (r(sub eff)) is found to be 1.85 +/- 0.3 microns at VL2 during northern summer when dust loading was low and 1.52 +/- 0.3 microns at VL1 during the first dust storm. In both cases the best cross-section weighted mean variance (nu(eff)) of the size distribution is equal to 0.5 +/- 0.2 microns. The changes in size distribution, and thus radiative properties, do not represent a substantial change in solar energy deposition in the atmosphere over the Pollack et al. (1977,1979) estimates.

Estimation of Mars radar backscatter from measured surface rock populations

USGS Publications Warehouse

Baron, J.E.; Simpson, R.A.; Tyler, G.L.; Moore, H.J.; Harmon, J.K.

1998-01-01

Reanalysis of rock population data at the Mars Viking Lander sites has yielded updated values of rock fractional surface coverage (about 0.16 at both sites, including outcrops) and new estimates of rock burial depths and axial ratios. These data are combined with a finite difference time domain (FDTD) numerical scattering model to estimate diffuse backscatter due to rocks at both the Lander l (VL1) and Lander 2 (VL2) sites. We consider single scattering from both surface and subsurface objects of various shapes, ranging from an ideal sphere to an accurate digitized model of a terrestrial rock. The FDTD cross-section calculations explicitly account for the size, shape, composition, orientation, and burial state of the scattering object, the incident wave angle and polarization, and the composition of the surface. We calculate depolarized specific cross sections at 12.6 cm wavelength due to lossless rock-like scatterers of about 0.014 at VL1 and 0.023 at VL2, which are comparable to the measured ranges of 0.019-0.032 and 0.012-0.018, respectively. We also discuss the variation of the diffuse cross section as the local angle of incidence, ??i, changes. Numerical calculations for a limited set of rock shapes indicate a marked difference between the angular backscattering behavior of wavelength-scale surface and subsurface rocks: while subsurface rocks scatter approximately as a cosine power law, surface rocks display a complex variation, often with peak backscattering at high incidence angles (??i = 70??-75??). Copyright 1998 by the American Geophysical Union.

Unresolved fine-scale structure in solar coronal loop-tops

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

Scullion, E.; Van der Voort, L. Rouppe; Wedemeyer, S.

2014-12-10

New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal loop substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric Hα 656.28 nm spectral line core and wings can, under certainmore » circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal loops, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in Hα) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal loop-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from loop-top to footpoint. We discover that coronal loop fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal loop cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal loops, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal loops.« less

Dual-high-frequency ultrasound excitation on microbubble destruction volume.

PubMed

Shen, Che-Chou; Su, Shin-Yuan; Cheng, Chih-Hao; Yeh, Chih-Kuang

2010-06-01

The goal of this work was to test experimentally that exposing air bubbles or ultrasound contrast agents in water to amplitude modulated wave allows control of inertial cavitation affected volume and hence could limit the undesirable bioeffects. Focused transducer operating at the center frequency of 10 MHz and having about 65% fractional bandwidth was excited by 3 micros 8.5 and 11.5 MHz tone-bursts to produce 3 MHz envelope signal. The 3 MHz frequency was selected because it corresponds to the resonance frequency of the microbubbles used in the experiment. Another 5 MHz transducer was used as a receiver to produce B-mode image. Peak negative acoustic pressure was adjusted in the range from 0.5 to 3.5 MPa. The spectrum amplitudes obtained from the imaging of SonoVue contrast agent when using the envelope and a separate 3 MHz transducer were compared to determine their cross-section at the -6 dB level. The conventional 3 MHz tone-burst excitation resulted in the region of interest (ROI) cross-section of 2.47 mm while amplitude modulated, dual-frequency excitation with difference frequency of 3 MHz produced cross-section equal to 1.2mm. These results corroborate our hypothesis that, in addition to the considerably higher penetration depth of dual-frequency excitation due to the lower attenuation at 3 MHz than that at 8.5 and 11.5 MHz, the sample volume of dual-frequency excitation is also smaller than that of linear 3-MHz method for more spatially confined destruction of microbubbles. 2010 Elsevier B.V. All rights reserved.

The importance of including local correlation times in the calculation of inter-proton distances from NMR measurements: ignoring local correlation times leads to significant errors in the conformational analysis of the Glc alpha1-2Glc alpha linkage by NMR spectroscopy.

PubMed

Mackeen, Mukram; Almond, Andrew; Cumpstey, Ian; Enis, Seth C; Kupce, Eriks; Butters, Terry D; Fairbanks, Antony J; Dwek, Raymond A; Wormald, Mark R

2006-06-07

The experimental determination of oligosaccharide conformations has traditionally used cross-linkage 1H-1H NOE/ROEs. As relatively few NOEs are observed, to provide sufficient conformational constraints this method relies on: accurate quantification of NOE intensities (positive constraints); analysis of absent NOEs (negative constraints); and hence calculation of inter-proton distances using the two-spin approximation. We have compared the results obtained by using 1H 2D NOESY, ROESY and T-ROESY experiments at 500 and 700 MHz to determine the conformation of the terminal Glc alpha1-2Glc alpha linkage in a dodecasaccharide and a related tetrasaccharide. For the tetrasaccharide, the NOESY and ROESY spectra produced the same qualitative pattern of linkage cross-peaks but the quantitative pattern, the relative peak intensities, was different. For the dodecasaccharide, the NOESY and ROESY spectra at 500 MHz produced a different qualitative pattern of linkage cross-peaks, with fewer peaks in the NOESY spectrum. At 700 MHz, the NOESY and ROESY spectra of the dodecasaccharide produced the same qualitative pattern of peaks, but again the relative peak intensities were different. These differences are due to very significant differences in the local correlation times for different proton pairs across this glycosidic linkage. The local correlation time for each proton pair was measured using the ratio of the NOESY and T-ROESY cross-relaxation rates, leaving the NOESY and ROESY as independent data sets for calculating the inter-proton distances. The inter-proton distances calculated including the effects of differences in local correlation times give much more consistent results.

Two-dimensional correlation spectroscopic studies on coordination between organic ligands and Ni2 + ions

NASA Astrophysics Data System (ADS)

Bao, Ya-nan; Zeng, Yi-wei; Guo, Ran; Ablikim, Mesude; Shi, Hai-fang; Yang, Li-min; Yang, Zhan-lan; Xu, Yi-zhuang; Noda, Isao; Wu, Jin-guang

2018-05-01

3A2g → 3T1g(P) transition band of Ni2 + is used to probe the coordination of Ni2 +. Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design (DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g → 3T1g(P) transition band of Ni2 + are utilized to probe coordination between Ni2 + and various ligands. We studied the spectral behavior of the 3A2g → 3T1g(P) transition band when Ni2 + is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2 + and galactitol is also investigated. Although no clearly observable change is found on the 3A2g → 3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2 + and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g → 3T1g(P) transition band of Ni(galactitol)x2 + is considerably different from those of Ni(H2O)62 +. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.

Temporal Differences in Flow Depth and Velocity Distributions and Hydraulic Microhabitats Near Bridges of the Lower Platte River, Nebraska, 1934-2006

USGS Publications Warehouse

Ginting, Daniel; Zelt, Ronald B.

2008-01-01

As part of a collaborative study of the cumulative impacts on stream and riparian ecology of water and channel management practices in the lower Platte River, Nebraska, this report describes a study by the U.S. Geological Survey in cooperation with the Lower Platte South Natural Resources District that summarizes: (1) temporal differences in distribution of streamflow depth, velocity, and microhabitats among five discrete 11-water-year periods 1934-44, 1951-61, 1966-76, 1985-95, and 1996-2006, and (2) the effects of bridge proximity on distribution of streamflow depth, velocity, and microhabitat of the Platte River when cross sections were measured at a similar discharge. The scope of the study included the four presently (2008) active streamflow-gaging stations located near bridges over the lower Platte River at North Bend, near Leshara, near Ashland, and at Louisville, Nebraska, and the most downstream streamflow-gaging station within the central Platte River segment near Duncan, Nebraska. Generally, in cases where temporal differences in streamflow depth and velocity were evident, at least one of the water-year periods from 1934 through 1995 had deeper streamflow than the recent water-year period (1996-2006). Temporal differences in distributions of streamflow depth were not strongly associated with differences in either climatic conditions or the maximum peak flow that occurred prior to the latest discharge measurement during each period. The relative cross-sectional area of most hydraulic niches did not differ among the water-year periods. Part of this apparent uniformity likely was an artifact of the broad microhabitat classification used for this study. In cases where temporal differences in relative cross-sectional area of hydraulic niches were evidenced, the differences occurred during high- and low-flow conditions, not during median flow conditions. The temporal differences in relative cross-sectional area were found more frequently for hydraulic niches defined by moderate and fast velocities than for hydraulic niches defined by slow velocities. Generally, any significant increase or decrease in the relative cross-sectional areas of hydraulic niches during the water-year periods from 1934 through 1995 had disappeared during the most recent water-year period, 1996-2006. Deep-Swift niche was the predominant hydraulic niche for all near-bridge sites on the lower Platte River for high- and median-flow conditions. The Deep-Swift niche also was the predominant niche for the near-bridge sites near Ashland and at Louisville for low-flow conditions; for the near-bridge sites at North Bend and near Leshara, streamflow cross-sectional areas during low-flow conditions were shared among the Shallow-Moderate, Intermediate-Moderate, Intermediate-Swift, and Deep-Swift hydraulic niches. For the near-bridge site near Duncan, the site farthest downstream in the central Platte River system, the Deep-Swift hydraulic niche was predominant only during high-flow conditions; during median- and low-flow conditions the relative cross-sectional area was shared among the Shallow-Slow, Shallow-Moderate, Intermediate-Moderate, and Intermediate-Swift hydraulic niches. Significant temporal differences in the relative cross-sectional area of the Deep-Swift hydraulic niche were found for sites near the two farthest downstream bridges near Ashland and at Louisville, but only for low-flow conditions. The Deep-Swift microhabitat was of special interest because it is the preferred hydraulic habitat during the adult life of the endangered pallid sturgeon (Scaphirhynchus albus). Temporal differences in relative cross-sectional areas of the Glide low-flow geomorphic microhabitat that contained the Deep-Swift hydraulic niche also indicated that relative cross-sectional areas of the Glide during the 1951-61 and 1996-2006 water-year periods were lower than during the 1966-76 period. The temporal differences indicated that any significant temporal chang

Shoulder disorders in an outpatient clinic: an epidemiological study.

PubMed

Malavolta, Eduardo Angeli; Gracitelli, Mauro Emilio Conforto; Assunção, Jorge Henrique; Pinto, Gustavo de Mello Ribeiro; da Silveira, Arthur Zorzi Freire; Ferreira, Arnaldo Amado

2017-01-01

To describe shoulder disorders in patients evaluated by two shoulder and elbow surgeons. This cross-sectional study analyzed patients evaluated by two authors, excluding acute fractures and dislocations and patients with symptoms not involving the shoulder. Age and sex distribution was determined for the different diagnoses. We evaluated 1001 patients. Mean age was 51.43±15.15 years and 51.0% were female. Disorders of the rotator cuff occurred in 64.3% (41.2% tendinopathy, 11.0% partial tears and 12.2% full-thickness tears). Adhesive capsulitis occurred in 13.5% of cases and glenohumeral instability in 8.1%. Rotator cuff disorders were more common in women, with a peak between 50 and 59 years for tendinopathy and partial tears and between 60 and 69 years for full-thickness tears. Glenohumeral instability was more frequent in men, with a peak between 30 and 39 years. The most frequent diagnosis was rotator cuff tendinopathy, followed by adhesive capsulitis, full-thickness rotator cuff tears, partial rotator cuff tears and glenohumeral instability. Rotator cuff lesions were more common in women, with a peak between 60 and 69 years for full-thickness tears. Level of Evidence IV, Case Series.

Effects of wheelchair propulsion on neuropathic pain and resting electroencephalography after spinal cord injury.

PubMed

Sato, Gosuke; Osumi, Michihiro; Morioka, Shu

2017-01-31

To investigate the effects of wheelchair propulsion on neuropathic pain and to examine resting electroencephalography pre- and post-wheelchair propulsion after spinal cord injury. Cross-sectional study. Eleven individuals with spinal cord injury and pain and 10 healthy controls. Single-session 15-min wheelchair propulsion and measurement of resting electroence-phalography. Effects of wheelchair propulsion were investigated using numerical rating scale (NRS) for neuropathic pain and short-form Profile of Mood States-Brief for mood. Peak alpha frequency on electroencephalography was calculated in 4 regions of interest; frontal, central, parietal and occipital areas. These outcomes were compared between pre- and post-wheelchair propulsion. Ten participants with spinal cord injury and all healthy controls completed the wheelchair propulsion exercise. NRS scores and negative mood were significantly improved following the wheelchair propulsion exercise. Pre-wheelchair propulsion, parietal and occipital peak alpha frequencies were significantly lower in the spinal cord injury group compared with the healthy controls group. Post-wheelchair propulsion, central peak alpha frequency increased in the spinal cord injury group. Wheelchair propulsion exercise temporarily decreased neuropathic pain intensity, improved negative mood, and modified alpha activity in spinal cord injury.

A novel four-dimensional analytical approach for analysis of complex samples.

PubMed

Stephan, Susanne; Jakob, Cornelia; Hippler, Jörg; Schmitz, Oliver J

2016-05-01

A two-dimensional LC (2D-LC) method, based on the work of Erni and Frei in 1978, was developed and coupled to an ion mobility-high-resolution mass spectrometer (IM-MS), which enabled the separation of complex samples in four dimensions (2D-LC, ion mobility spectrometry (IMS), and mass spectrometry (MS)). This approach works as a continuous multiheart-cutting LC system, using a long modulation time of 4 min, which allows the complete transfer of most of the first - dimension peaks to the second - dimension column without fractionation, in comparison to comprehensive two-dimensional liquid chromatography. Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Ginkgo biloba shows the separation power of this four-dimensional separation method with a calculated total peak capacity of more than 8700. Furthermore, the advantage of ion mobility for characterizing unknown compounds by their collision cross section (CCS) and accurate mass in a non-target approach is shown for different matrices like plant extracts and coffee. Graphical abstract Principle of the four-dimensional separation.

Effects of Foot Strike and Step Frequency on Achilles Tendon Stress During Running.

PubMed

Lyght, Michael; Nockerts, Matthew; Kernozek, Thomas W; Ragan, Robert

2016-08-01

Achilles tendon (AT) injuries are common in runners. The AT withstands high magnitudes of stress during running which may contribute to injury. Our purpose was to examine the effects of foot strike pattern and step frequency on AT stress and strain during running utilizing muscle forces based on a musculoskeletal model and subject-specific ultrasound-derived AT cross-sectional area. Nineteen female runners performed running trials under 6 conditions, including rearfoot strike and forefoot strike patterns at their preferred cadence, +5%, and -5% preferred cadence. Rearfoot strike patterns had less peak AT stress (P < .001), strain (P < .001), and strain rate (P < .001) compared with the forefoot strike pattern. A reduction in peak AT stress and strain were exhibited with a +5% preferred step frequency relative to the preferred condition using a rearfoot (P < .001) and forefoot (P=.005) strike pattern. Strain rate was not different (P > .05) between step frequencies within each foot strike condition. Our results suggest that a rearfoot pattern may reduce AT stress, strain, and strain rate. Increases in step frequency of 5% above preferred frequency, regardless of foot strike pattern, may also lower peak AT stress and strain.

Respiratory symptoms and peak expiratory flow rates in workers of a Nigerian soap and detergent industry.

PubMed

Bamidele, J O

2002-01-01

This comparative cross-sectional study was carried out to assess the respiratory symptoms and peak expiratory flow rates of the factory(study group) and office(control group) workers in a soap and detergent industry in Ilorin in relation to the occupational hazards of chemical fumes and detergent dust in the industry. Upper respiratory tract infections were found in 67.5% and 10.6% of the study group and control group respectively. The study shows that the factory workers experienced hazards (e.g. chemical fumes and detergent dust) at work more than the office workers. Personal protective devices such as boots, face masks, gloves, earmuffs and goggles were not consistently used since they were inadequate in supply, worn out and of substandard qualities. The general reduction in the mean values of peak expiratory flow rate in the factory workers than in the office workers as observed in this study may possibly, be a pointer to the effect of industrial exposure to chemical fumes and detergent dust over the years. There is the need to follow up these workers in order to detect early any possible disease and complications that may arise.

Effects of indoor air pollution on lung function of primary school children in Kuala Lumpur

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

Azizi, B.H.; Henry, R.L.

1990-01-01

In a cross-sectional study of 7-12 year-old primary school children in Kuala Lumpur city, lung function was assessed by spirometric and peak expiratory flow measurements. Spirometric and peak expiratory flow measurements were successfully performed in 1,214 and 1,414 children, respectively. As expected, the main predictors of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), and peak expiratory flow rate (PEFR) were standing height, weight, age, and sex. In addition, lung function values of Chinese and Malays were generally higher than those of Indians. In multiple regressionmore » models which included host and environmental factors, asthma was associated with significant decreases in FEV1, FEF25-75, and PEFR. However, family history of chest illness, history of allergies, low paternal education, and hospitalization during the neonatal period were not independent predictors of lung function. Children sharing rooms with adult smokers had significantly lower levels of FEF25-75. Exposures to wood or kerosene stoves were, but to mosquito repellents were not, associated with decreased lung function.« less

Surface roughness measuring system. [synthetic aperture radar measurements of ocean wave height and terrain peaks

NASA Technical Reports Server (NTRS)

Jain, A. (Inventor)

1978-01-01

Significant height information of ocean waves, or peaks of rough terrain is obtained by compressing the radar signal over different widths of the available chirp or Doppler bandwidths, and cross-correlating one of these images with each of the others. Upon plotting a fixed (e.g., zero) component of the cross-correlation values as the spacing is increased over some empirically determined range, the system is calibrated. To measure height with the system, a spacing value is selected and a cross-correlation value is determined between two intensity images at a selected frequency spacing. The measured height is the slope of the cross-correlation value used. Both electronic and optical radar signal data compressors and cross-correlations are disclosed for implementation of the system.

Estimating Body Composition in Adolescent Sprint Athletes: Comparison of Different Methods in a 3 Years Longitudinal Design

PubMed Central

Aerenhouts, Dirk

2015-01-01

A recommended field method to assess body composition in adolescent sprint athletes is currently lacking. Existing methods developed for non-athletic adolescents were not longitudinally validated and do not take maturation status into account. This longitudinal study compared two field methods, i.e., a Bio Impedance Analysis (BIA) and a skinfold based equation, with underwater densitometry to track body fat percentage relative to years from age at peak height velocity in adolescent sprint athletes. In this study, adolescent sprint athletes (34 girls, 35 boys) were measured every 6 months during 3 years (age at start = 14.8 ± 1.5yrs in girls and 14.7 ± 1.9yrs in boys). Body fat percentage was estimated in 3 different ways: 1) using BIA with the TANITA TBF 410; 2) using a skinfold based equation; 3) using underwater densitometry which was considered as the reference method. Height for age since birth was used to estimate age at peak height velocity. Cross-sectional analyses were performed using repeated measures ANOVA and Pearson correlations between measurement methods at each occasion. Data were analyzed longitudinally using a multilevel cross-classified model with the PROC Mixed procedure. In boys, compared to underwater densitometry, the skinfold based formula revealed comparable values for body fatness during the study period whereas BIA showed a different pattern leading to an overestimation of body fatness starting from 4 years after age at peak height velocity. In girls, both the skinfold based formula and BIA overestimated body fatness across the whole range of years from peak height velocity. The skinfold based method appears to give an acceptable estimation of body composition during growth as compared to underwater densitometry in male adolescent sprinters. In girls, caution is warranted when interpreting estimations of body fatness by both BIA and a skinfold based formula since both methods tend to give an overestimation. PMID:26317426

A novel fast phase correlation algorithm for peak wavelength detection of Fiber Bragg Grating sensors.

PubMed

Lamberti, A; Vanlanduit, S; De Pauw, B; Berghmans, F

2014-03-24

Fiber Bragg Gratings (FBGs) can be used as sensors for strain, temperature and pressure measurements. For this purpose, the ability to determine the Bragg peak wavelength with adequate wavelength resolution and accuracy is essential. However, conventional peak detection techniques, such as the maximum detection algorithm, can yield inaccurate and imprecise results, especially when the Signal to Noise Ratio (SNR) and the wavelength resolution are poor. Other techniques, such as the cross-correlation demodulation algorithm are more precise and accurate but require a considerable higher computational effort. To overcome these problems, we developed a novel fast phase correlation (FPC) peak detection algorithm, which computes the wavelength shift in the reflected spectrum of a FBG sensor. This paper analyzes the performance of the FPC algorithm for different values of the SNR and wavelength resolution. Using simulations and experiments, we compared the FPC with the maximum detection and cross-correlation algorithms. The FPC method demonstrated a detection precision and accuracy comparable with those of cross-correlation demodulation and considerably higher than those obtained with the maximum detection technique. Additionally, FPC showed to be about 50 times faster than the cross-correlation. It is therefore a promising tool for future implementation in real-time systems or in embedded hardware intended for FBG sensor interrogation.

Backwater at bridges and densely wooded flood plains, west fork Amite River near Liberty, Mississippi

USGS Publications Warehouse

Colson, B.E.; Ming, C.O.; Arcement, George J.

1979-01-01

Floodflow data that will provide a base for evaluating digital models relating to open-channel flow were obtained at 22 sites on streams in Alabama, Louisiana, and Mississippi. Thirty-five floods were measured. Analysis of the data indicated methods currently in use would be inaccurate where densely vegetated flood plains are crossed by highway embankments and single-opening bridges. This atlas presents flood information at the site on West Fork Amite River near Liberty, MS. Water depths , velocities, and discharges through bridge openings on West Fork Amite River near Liberty, MS for floods of December 6, 1971 , and March 25, 1973, are shown, together with peak water-surface elevations along embankments and along cross sections. Manning 's roughness coefficient values in different parts of the flood plain are shown on maps, and flood-frequency relations are shown on a graph. (USGS).

Aortic arch shape is not associated with hypertensive response to exercise in patients with repaired congenital heart diseases.

PubMed

Ntsinjana, Hopewell N; Biglino, Giovanni; Capelli, Claudio; Tann, Oliver; Giardini, Alessandro; Derrick, Graham; Schievano, Silvia; Taylor, Andrew M

2013-11-12

Aortic arch geometry is linked to abnormal blood pressure (BP) response to maximum exercise. This study aims to quantitatively assess whether aortic arch geometry plays a role in blood pressure (BP) response to exercise. 60 age- and BSA-matched subjects--20 post-aortic coarctation (CoA) repair, 20 transposition of great arteries post arterial switch operation (ASO) and 20 healthy controls--had a three-dimensional (3D), whole heart magnetic resonance angiography (MRA) at 1.5 Tesla, 3D geometric reconstructions created from the MRA. All subjects underwent cardiopulmonary exercise test on the same day as MRA using an ergometer cycle with manual BP measurements. Geometric analysis and their correlation with BP at peak exercise were assessed. Arch curvature was similarly acute in both the post-CoA and ASO cases [0.05 ± 0.01 vs. 0.05 ± 0.01 (1/mm/m²); p = 1.0] and significantly different to that of normal healthy controls [0.05 ± 0.01 vs. 0.03 ± 0.01 (1/mm/m²), p < 0.001]. Indexed transverse arch cross sectional area were significantly abnormal in the post-CoA cases compared to the ASO cases (117.8 ± 47.7 vs. 221.3 ± 44.6; p < 0.001) and controls (117.8 ± 47.7 vs. 157.5 ± 27.2 mm²; p = 0.003). BP response to peak exercise did not correlate with arch curvature (r = 0.203, p = 0.120), but showed inverse correlation with indexed minimum cross sectional area of transverse arch and isthmus (r = -0.364, p = 0.004), and ratios of minimum arch area/ descending diameter (r = -0.491, p < 0.001). Transverse arch and isthmus hypoplasia, rather than acute arch angulation plays a role in the pathophysiology of BP response to peak exercise following CoA repair.

Intraabdominal pressure in women during CrossFit exercises and the effect of age and parity

PubMed Central

Gephart, Laura Faye; Doersch, Karen M.; Reyes, Michelle; Kuehl, Thomas J.; Danford, Jill M.

2018-01-01

ABSTRACT To determine intraabdominal pressure (IAP) in women during CrossFit and to determine whether parity, age, or CrossFit experience affects IAP during CrossFit exercises, we evaluated 10 women: 5 experienced and active CrossFitters and 5 who were not regularly engaged in CrossFit. A Laborie urodynamics abdominal pressure probe with the Goby wireless system measured IAP during 10 repetitions of 13 different CrossFit exercises. Women had a mean age of 36 years. A significant difference was found between mean peak IAP of the 5 parous vs the 5 nulliparous women (P = 0.009). Experience with CrossFit did not affect mean peak IAP achieved with exercise. In some exercises, there was a significant change in IAP as participants progressed through repetitions (P = 0.003 for back squats and 0.04 for sit-ups). Participants achieved IAP values that were markedly higher than those previously published. PMID:29904290

Accurate determinations of one-bond 13C-13C couplings in 13C-labeled carbohydrates

NASA Astrophysics Data System (ADS)

Azurmendi, Hugo F.; Freedberg, Darón I.

2013-03-01

Carbon plays a central role in the molecular architecture of carbohydrates, yet the availability of accurate methods for 1DCC determination has not been sufficiently explored, despite the importance that such data could play in structural studies of oligo- and polysaccharides. Existing methods require fitting intensity ratios of cross- to diagonal-peaks as a function of the constant-time (CT) in CT-COSY experiments, while other methods utilize measurement of peak separation. The former strategies suffer from complications due to peak overlap, primarily in regions close to the diagonal, while the latter strategies are negatively impacted by the common occurrence of strong coupling in sugars, which requires a reliable assessment of their influence in the context of RDC determination. We detail a 13C-13C CT-COSY method that combines a variation in the CT processed with diagonal filtering to yield 1JCC and RDCs. The strategy, which relies solely on cross-peak intensity modulation, is inspired in the cross-peak nulling method used for JHH determinations, but adapted and extended to applications where, like in sugars, large one-bond 13C-13C couplings coexist with relatively small long-range couplings. Because diagonal peaks are not utilized, overlap problems are greatly alleviated. Thus, one-bond couplings can be determined from different cross-peaks as either active or passive coupling. This results in increased accuracy when more than one determination is available, and in more opportunities to measure a specific coupling in the presence of severe overlap. In addition, we evaluate the influence of strong couplings on the determination of RDCs by computer simulations. We show that individual scalar couplings are notably affected by the presence of strong couplings but, at least for the simple cases studied, the obtained RDC values for use in structural calculations were not, because the errors introduced by strong couplings for the isotropic and oriented phases are very similar and therefore cancel when calculating the difference to determine 1DCC values.

Microlensing of Extremely Magnified Stars near Caustics of Galaxy Clusters

NASA Astrophysics Data System (ADS)

Venumadhav, Tejaswi; Dai, Liang; Miralda-Escudé, Jordi

2017-11-01

Recent observations of lensed galaxies at cosmological distances have detected individual stars that are extremely magnified when crossing the caustics of lensing clusters. In idealized cluster lenses with smooth mass distributions, two images of a star of radius R approaching a caustic brighten as {t}-1/2 and reach a peak magnification ˜ {10}6{(10{R}⊙ /R)}1/2 before merging on the critical curve. We show that a mass fraction ({κ }\\star ≳ {10}-4.5) in microlenses inevitably disrupts the smooth caustic into a network of corrugated microcaustics and produces light curves with numerous peaks. Using analytical calculations and numerical simulations, we derive the characteristic width of the network, caustic-crossing frequencies, and peak magnifications. For the lens parameters of a recent detection and a population of intracluster stars with {κ }\\star ˜ 0.01, we find a source-plane width of ˜ 20 {pc} for the caustic network, which spans 0.2 {arcsec} on the image plane. A source star takes ˜ 2× {10}4 years to cross this width, with a total of ˜ 6× {10}4 crossings, each one lasting for ˜ 5 {hr} (R/10 {R}⊙ ) with typical peak magnifications of ˜ {10}4 {(R/10{R}⊙ )}-1/2. The exquisite sensitivity of caustic-crossing events to the granularity of the lens-mass distribution makes them ideal probes of dark matter components, such as compact halo objects and ultralight axion dark matter.

Characterization of early dental caries by polarized Raman spectroscopy

NASA Astrophysics Data System (ADS)

Choo-Smith, Lin-P'ing; Ko, Alex C.-T.; Hewko, Mark D.; Dong, Cecilia C.; Cleghorn, Blaine M.; Sowa, Michael G.

2006-02-01

The early approximal caries lesion in enamel is observed clinically as a white spot and is difficult to detect and/or monitor with current methods available to dentists. New methods with high sensitivity and specificity are required to enable improved early dental caries diagnosis. Using unpolarized Raman spectroscopy to examine unsectioned teeth, peak intensity changes in the phosphate (PO 4 3-) vibrations (ν II, ν 3 and ν 4) were observed between spectra of sound and carious enamel. However, there is little change in the ν I vibration with this approach. In contrast, when tooth sections were examined by unpolarized Raman spectroscopy, marked changes in the ν I peak at 959 cm -1 were noted between healthy and carious enamel. These differences suggest that sampling orientation play a role in understanding the spectral changes. Using polarized Raman spectroscopy to examine unsectioned samples, cross polarized measurements from sound enamel exhibited significant reduction of the ν I peak compared with parallel polarized measurements. A similar reduction was observed with carious enamel, however, the reduction was not as prominent. By calculating the depolarization ratio of the area under the ν I peak, sound enamel can be clearly distinguished from demineralized regions. The spectral changes observed are attributed to changes in the structure and/or orientation of the apatite crystals as a result of the acid demineralization process.

The Cardiovascular Function Profile and Physical Fitness in Overweight Subjects

NASA Astrophysics Data System (ADS)

Megawati, E. R.; Lubis, L. D.; Harahap, F. Y.

2017-03-01

Obesity in children and young adult is associated with cardiovascular risk in short term and long term. The aim of this study was to describe the profile of the cardiovascular functions parameters and physical fitness in overweight. This is an analytical observational study with cross sectional approach. The samples of this study were 85 randomly selected subjects aged 18 to 24 years with normoweight and body mass index <40. The parameters measures were body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), cardiovascular function parameters (resting pulse, blood pressure, and peak flow meter) and physical fitness parameters (VO2max dengan McArdle step test). The mean BMI was 24,53±4,929. The WC and WHR mean were 86,7±14,10 cms and 0,89±0,073 cm respectively. The mean of resting pulses were higher in normoweight subject (p=0,0209). The mean systole were lower in normoweight subject (p=0,0026). No differences VO2 max between groups (p=0,3888). The peak flow meter was higher in normoweight (p=0,0274). The result of this study indicate that heart rate, systole and peak flow meter are signifantly different between groups. The heart rate and the peak flow meter in the overweight subjects were lower meanwhile the systole blood pressure was higher compared to normoweight subjects.

Precision imaging of 4.4 MeV gamma rays using a 3-D position sensitive Compton camera.

PubMed

Koide, Ayako; Kataoka, Jun; Masuda, Takamitsu; Mochizuki, Saku; Taya, Takanori; Sueoka, Koki; Tagawa, Leo; Fujieda, Kazuya; Maruhashi, Takuya; Kurihara, Takuya; Inaniwa, Taku

2018-05-25

Imaging of nuclear gamma-ray lines in the 1-10 MeV range is far from being established in both medical and physical applications. In proton therapy, 4.4 MeV gamma rays are emitted from the excited nucleus of either 12 C* or 11 B* and are considered good indicators of dose delivery and/or range verification. Further, in gamma-ray astronomy, 4.4 MeV gamma rays are produced by cosmic ray interactions in the interstellar medium, and can thus be used to probe nucleothynthesis in the universe. In this paper, we present a high-precision image of 4.4 MeV gamma rays taken by newly developed 3-D position sensitive Compton camera (3D-PSCC). To mimic the situation in proton therapy, we first irradiated water, PMMA and Ca(OH)2 with a 70 MeV proton beam, then we identified various nuclear lines with the HPGe detector. The 4.4 MeV gamma rays constitute a broad peak, including single and double escape peaks. Thus, by setting an energy window of 3D-PSCC from 3 to 5 MeV, we show that a gamma ray image sharply concentrates near the Bragg peak, as expected from the minimum energy threshold and sharp peak profile in the cross section of 12 C(p,p) 12 C*.

Transmission, reflection and thermoluminescence studies on GaS{sub 0.75}Se{sub 0.25} layered single crystals

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

Delice, S., E-mail: sdelice@metu.edu.tr; Isik, M.; Gasanly, N.M.

2015-10-15

Highlights: • Optical and thermoluminescence properties of Ga{sub 4}S{sub 3}Se crystals were investigated. • Indirect and direct band gap energies were found as 2.39 and 2.53 eV, respectively. • The activation energy of the trap center was determined as 495 meV. - Abstract: Optical and thermoluminescence properties on GaS{sub 0.75}Se{sub 0.25} crystals were investigated in the present work. Transmission and reflection measurements were performed at room temperature in the wavelength range of 400–1000 nm. Analysis revealed the presence of indirect and direct transitions with band gap energies of 2.39 and 2.53 eV, respectively. TL spectra obtained at low temperatures (10–300more » K) exhibited one peak having maximum temperature of 168 K. Observed peak was analyzed using curve fitting, initial rise and peak shape methods to calculate the activation energy of the associated trap center. All applied methods were consistent with the value of 495 meV. Attempt-to-escape-frequency and capture cross section of the trap center were determined using the results of curve fitting. Heating rate dependence studies of the glow curve in the range of 0.4–0.8 K/s resulted with decrease of TL intensity and shift of the peak maximum temperature to higher values.« less

Poor correlation between handgrip strength and isokinetic performance of knee flexor and extensor muscles in community-dwelling elderly women.

PubMed

Felicio, Diogo Carvalho; Pereira, Daniele Sirineu; Assumpção, Alexandra Miranda; de Jesus-Moraleida, Fabianna Resende; de Queiroz, Barbara Zille; da Silva, Juscelio Pereira; de Brito Rosa, Naysa Maciel; Dias, João Marcos Domingues; Pereira, Leani Souza Máximo

2014-01-01

To investigate the correlation between handgrip strength and performance of knee flexor and extensor muscles determined using an isokinetic dynamometer in community-dwelling elderly women. This was a cross-sectional study. Sample selection for the study was made by convenience, and 221 (71.07 ± 4.93 years) community-dwelling elderly women were included. Knee flexor and extensor muscle performance was measured using an isokinetic dynamometer Biodex System 3 Pro. The isokinetic variables chosen for analysis were peak torque, peak torque/bodyweight, total work/bodyweight, total work, average power, and agonist/antagonist ratio at the angular velocities of 60°/s and 180°/s. Assessment of handgrip strength was carried out using the Jamar dynamometer. Spearman's correlation coefficient was calculated to identify intervariable correlations. Only knee flexor peak torque (60°/s) and average power (60°/s), and knee extensor peak torque (180°/s) and total work (180°/s) were significantly (P < 0.05), yet poorly, correlated with handgrip strength (r < 0.30). The majority of analyses did not show any correlation between variables assessed by isokinetic dynamometer and handgrip dynamometer. Caution is required when generalizing handgrip strength as a predictor of global muscle strength in community-dwelling elderly women. © 2013 Japan Geriatrics Society.

A discrete Fourier-encoded, diagonal-free experiment to simplify homonuclear 2D NMR correlations.

PubMed

Huang, Zebin; Guan, Quanshuai; Chen, Zhong; Frydman, Lucio; Lin, Yulan

2017-07-21

Nuclear magnetic resonance (NMR) spectroscopy has long served as an irreplaceable, versatile tool in physics, chemistry, biology, and materials sciences, owing to its ability to study molecular structure and dynamics in detail. In particular, the connectivity of chemical sites within molecules, and thereby molecular structure, becomes visible by multi-dimensional NMR. Homonuclear correlation experiments are a powerful tool for identifying coupled spins. Generally, diagonal peaks in these correlation spectra display the strongest intensities and do not offer any new information beyond the standard one-dimensional spectrum, whereas weaker, symmetrically placed cross peaks contain most of the coupling information. The cross peaks near the diagonal are often affected by the tails of strong diagonal peaks or even obscured entirely by the diagonal. In this paper, we demonstrate a homonuclear encoding approach based on imparting a discrete phase modulation of the targeted cross peaks and combine it with a site-selective sculpting scheme, capable of simplifying the patterns arising in these 2D correlation spectra. The theoretical principles of the new methods are laid out, and experimental observations are rationalized on the basis of theoretical analyses. The ensuing techniques provide a new way to retrieve 2D coupling information within homonuclear spin systems, with enhanced sensitivity, speed, and clarity.

A discrete Fourier-encoded, diagonal-free experiment to simplify homonuclear 2D NMR correlations

NASA Astrophysics Data System (ADS)

Huang, Zebin; Guan, Quanshuai; Chen, Zhong; Frydman, Lucio; Lin, Yulan

2017-07-01

Nuclear magnetic resonance (NMR) spectroscopy has long served as an irreplaceable, versatile tool in physics, chemistry, biology, and materials sciences, owing to its ability to study molecular structure and dynamics in detail. In particular, the connectivity of chemical sites within molecules, and thereby molecular structure, becomes visible by multi-dimensional NMR. Homonuclear correlation experiments are a powerful tool for identifying coupled spins. Generally, diagonal peaks in these correlation spectra display the strongest intensities and do not offer any new information beyond the standard one-dimensional spectrum, whereas weaker, symmetrically placed cross peaks contain most of the coupling information. The cross peaks near the diagonal are often affected by the tails of strong diagonal peaks or even obscured entirely by the diagonal. In this paper, we demonstrate a homonuclear encoding approach based on imparting a discrete phase modulation of the targeted cross peaks and combine it with a site-selective sculpting scheme, capable of simplifying the patterns arising in these 2D correlation spectra. The theoretical principles of the new methods are laid out, and experimental observations are rationalized on the basis of theoretical analyses. The ensuing techniques provide a new way to retrieve 2D coupling information within homonuclear spin systems, with enhanced sensitivity, speed, and clarity.

Thermoelastic Damping in Cone Microcantilever Resonator

NASA Astrophysics Data System (ADS)

Li, Pu; Zhou, Hongyue

2017-07-01

Microbeams with continuous or discontinuous variable cross-section have been applied in Microelectromechanical Systems (MEMS) resonators, such as tapered microbeam, torsion microbeam and stepped microbeam. Thermoelastic damping (TED), which is verified as a fundamental energy lost mechanism for microresonators, is calculated by the Zener’s model and Lifshits and Roukes’s (LR) model in general. However, for non-uniform microbeam resonators, these two classical models are not suitable in some cases. On the basis of Zener’s theory, a TED model for cone microcantilever with rectangular cross-section has been derived in this study. The comparison of results obtained by the present model and Finite Element Method (FEM) model proves that the proposed model is able to predict TED value for cone microcantilever. In addition, TED in cone microcantilever is nearly same as TED in wedge microcantilever. The results show that quality factors (Q-factors) of cone microcantilever and wedge microcantilever are larger than Q-factor of uniform microbeam at low frequencies. The Debye peak value of a uniform microcantilever is equal to 0.5Δ E , while those of cone microcantilever and wedge microcantilever are about 0.438ΔE and 0.428ΔE, respectively.

Structural and luminescence studies of Ho{sup 3+}-doped zinc-aluminium-sodium-phosphate (ZANP) glasses

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

Brahmachary, K.; Rajesh, D.; Ratnakaram, Y. C., E-mail: ratnakaramsvu@gmail.com

Trivalent holmium doped zinc-aluminium-sodium-phosphate (ZANP) glasses were prepared by conventional melt-quenching technique and characterized for their structural and luminescence properties. The amorphous nature, elemental analysis and thermal stability of the glasses were studied by using X-ray diffraction, energy dispersive spectrum and differential scanning calorimetry analysis, respectively. The absorption and fluorescence spectra have been recorded at room temperature. Based on the absorption spectra, the Judd-Ofelt parameters and radiative parameters such as spontaneous transition probabilities (A{sub R}), branching ratios (β{sub R}), radiative lifetimes (τ{sub R}) were calculated and discussed. From the emission spectra emission peak positions (λ{sub P}), effective bandwidths (Δλ{sub eff})more » and stimulated emission cross-sections (σ{sub P}) were calculated for the observed emission transitions,{sup 5}S{sub 2} ({sup 5}F{sub 4}→{sup 5}I{sub 8}) and {sup 5}F{sub 5}→{sup 5}I{sub 8} in all the glass samples. The stimulated emission cross-section is higher for ZANPHo10 glass matrix and so it may be useful for laser excitation.« less

Seroepidemiology of Toxoplasma in a coastal region of Haiti; Multiplex bead assay detection of immunoglobulin G antibodies that recognize the SAG2A antigen

PubMed Central

Priest, J. W.; Moss, D. M.; Arnold, B. F.; Hamlin, K.; Jones, C. C.; Lammie, P. J.

2018-01-01

Summary Toxoplasma gondii is a globally distributed parasitic protozoan that infects most warm blooded animals. We incorporated a bead coupled with recombinant SAG2A protein into our Neglected Tropical Disease (NTD) multiplex bead assay (MBA) panel and used it to determine Toxoplasma infection rates in two studies in Haiti. In a longitudinal cohort study of children 0–11 years old, the infection rate varied with age reaching a maximum of 0.131 infections/ year in children 3 years of age (95% CI = 0.065, 0.204). The median time to seroconversion was estimated to be 9.7 years (95% CI = 7.6, ∞). In a cross-sectional, community-wide survey of residents of all ages, we determined an overall seroprevalence of 28.2%. The seroprevalence age curve from the cross-sectional study also suggested that the force of infection varied with age and peaked at 0.057 infections/ year (95% CI = 0.033, 0.080) at 2.6 years of age. Integration of the Toxoplasma MBA into NTD surveys may allow for better estimates of the potential burden of congenital toxoplasmosis in underserved regions. PMID:25600668

Simulation of the Velocity and Temperature Distribution of Inhalation Thermal Injury in a Human Upper Airway Model by Application of Computational Fluid Dynamics.

PubMed

Chang, Yang; Zhao, Xiao-zhuo; Wang, Cheng; Ning, Fang-gang; Zhang, Guo-an

2015-01-01

Inhalation injury is an important cause of death after thermal burns. This study was designed to simulate the velocity and temperature distribution of inhalation thermal injury in the upper airway in humans using computational fluid dynamics. Cervical computed tomography images of three Chinese adults were imported to Mimics software to produce three-dimensional models. After grids were established and boundary conditions were defined, the simulation time was set at 1 minute and the gas temperature was set to 80 to 320°C using ANSYS software (ANSYS, Canonsburg, PA) to simulate the velocity and temperature distribution of inhalation thermal injury. Cross-sections were cut at 2-mm intervals, and maximum airway temperature and velocity were recorded for each cross-section. The maximum velocity peaked in the lower part of the nasal cavity and then decreased with air flow. The velocities in the epiglottis and glottis were higher than those in the surrounding areas. Further, the maximum airway temperature decreased from the nasal cavity to the trachea. Computational fluid dynamics technology can be used to simulate the velocity and temperature distribution of inhaled heated air.

Electron impact fragmentation of thymine: partial ionization cross sections for positive fragments

NASA Astrophysics Data System (ADS)

van der Burgt, Peter J. M.; Mahon, Francis; Barrett, Gerard; Gradziel, Marcin L.

2014-06-01

We have measured mass spectra for positive ions for low-energy electron impact on thymine using a reflectron time-of-flight mass spectrometer. Using computer controlled data acquisition, mass spectra have been acquired for electron impact energies up to 100 eV in steps of 0.5 eV. Ion yield curves for most of the fragment ions have been determined by fitting groups of adjacent peaks in the mass spectra with sequences of normalized Gaussians. The ion yield curves have been normalized by comparing the sum of the ion yields to the average of calculated total ionization cross sections. Appearance energies have been determined. The nearly equal appearance energies of 83 u and 55 u observed in the present work strongly indicate that near threshold the 55 u ion is formed directly by the breakage of two bonds in the ring, rather than from a successive loss of HNCO and CO from the parent ion. Likewise 54 u is not formed by CO loss from 82 u. The appearance energies are in a number of cases consistent with the loss of one or more hydrogen atoms from a heavier fragment, but 70 u is not formed by hydrogen loss from 71 u.

Fabrication of 5 at.%Yb:(La0.1Y0.9)2O3 transparent ceramics by chemical precipitation and vacuum sintering

NASA Astrophysics Data System (ADS)

Li, Shanshan; Zhu, Xingwen; Li, Jiang; Yavetskiy, Roman; Ivanov, Maxim; Liu, Binglong; Liu, Wenbin; Pan, Yubai

2017-09-01

Yttria (Y2O3) nanopowders were synthesized by a normal precipitation method using (NH4)2SO4 as dispersing agent. Pure Y2O3 powders without any other phase can be achieved by calcining the precursor at 600 °C for 4 h. The precursor and Y2O3 powders were characterized by TG-DTA, XRD, SEM and BET. In this work, 5 at.%Yb:(La0.1Y1.9)2O3 transparent ceramics were made by vacuum sintering at 1650 °C for 10 h. The in-line transmittance of the 5 at.%Yb:(La0.1Y0.9)2O3 ceramics is 81.3% at the wavelength of 1031 nm. The absorption cross-sections of the sample are calculated to be 1.20 × 10-20 cm2, 5.74 × 10-21 cm2 and 4.18 × 10-21 cm2 at 976, 951 and 906 nm, respectively. The emission cross-sections of the emission peak located at around 1031 and 1073 nm are 1.13 × 10-20 and 0.42 × 10-20 cm2, respectively.

Genital warts in men: a large population-based cross-sectional survey of Danish men.

PubMed

Munk, Christian; Nielsen, Ann; Liaw, Kai-Li; Kjaer, Susanne Krüger

2012-12-01

To estimate the occurrence of and risk factors associated with genital warts in Danish men We conducted a cross-sectional, questionnaire-based study among almost 23 000 men aged 18-45 years, randomly sampled from the general population of Denmark. Data was collected on self-reported clinically diagnosed genital warts, and various lifestyle habits. Ever having had clinically diagnosed genital warts was reported by 7.9% of the men. The median age at first occurrence was 22 years. Genital warts within the previous 12 months were reported by 0.92% of the men, with a peak of 1.83% among men aged 21-24 years. The likelihood of reporting genital warts was strongly correlated with the lifetime number of sex partners (OR 8.0; 95% CI 6.0 to 10.8 for ≥15 partners vs 1-2 partners). Other factors associated with an increased risk for genital warts included ever having smoked and having had other sexually transmitted infections. Almost 8% of Danish men aged 18-45 years reported having had a diagnosis of genital warts. The results provide baseline information for developing and monitoring prevention strategies against genital warts, such as vaccination against human papillomavirus types 6 and 11.

Ionospheric dynamo theory for production of far ultraviolet emissions on Uranus

NASA Technical Reports Server (NTRS)

Hudson, M. K.; Warren, J. A.; Clarke, J. T.

1989-01-01

A model is presented to explain diffuse FUV emissions from the outer planets, specifically Uranus, in excess of those diffuse emissions that are currently explainable by scattering of sunlight and/or excitation by photoelectrons. These electroglow emissions in H Ly-alpha and H2 bands, which occur in the sunlit hemisphere slightly above the homopause, appear to require particle excitation in the 10- to 50-eV range. An in situ mechanism for accelerating photoelectrons (and ions is proposed, involving neutral wind dynamo generation of field-aligned currents analogous to what occurs in the earth's equatorial E and F regions. Sufficiently strong field-aligned currents are found in the model calculation for Uranus to produce a potential drop of about 100 eV or greater between the F peak and homopause, concentrated at lower altitudes, and capable in principle of accelerating photoelectrons (and ions) to the 10- to 50-eV energies required to explain the observed emissions. The fact that the excitation and ionization cross sections are larger than elastic scattering cross sections in an H2 atmosphere at these energies makes in situ acceleration feasible for the production of UV on the outer planets.

Collimated electron beam accelerated at 12 kV from a Penning discharge.

PubMed

Toader, D; Oane, M; Ticoş, C M

2015-01-01

A pulsed electron beam accelerated at 12 kV with a duration of 40 μs per pulse is obtained from a Penning discharge with a hollow anode and two cathodes. The electrons are extracted through a hole in one of the cathodes and focused by a pair of coils. The electron beam has a diameter of a few mm in the cross section, while the beam current reaches peak values of 400 mA, depending on the magnetic field inside the focussing coils. This relatively inexpensive and compact device is suitable for the irradiation of small material samples placed in high vacuum.

Resonant inelastic x-ray scattering on iso-C{sub 2}H{sub 2}Cl{sub 2} around the chlorine K-edge: Structural and dynamical aspects

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

Kawerk, Elie, E-mail: eliekawerk@hotmail.com, E-mail: ekawerk@units.it; Sorbonne Universités, UPMC Université Paris 06, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris; Laboratoire de Physique Appliquée, Faculté des Sciences II, Université Libanaise, 90656 Jdeidet el Metn, Liban

2014-10-14

We report a theoretical and experimental study of the high resolution resonant K{sub α} X-ray emission lines around the chlorine K-edge in gas phase 1,1-dichloroethylene. With the help of ab initio electronic structure calculations and cross section evaluation, we interpret the lowest lying peak in the X-ray absorption and emission spectra. The behavior of the K{sub α} emission lines with respect to frequency detuning highlights the existence of femtosecond nuclear dynamics on the dissociative Potential Energy Surface of the first K-shell core-excited state.

[Osteosarcoma: reliability and quality of the information in the internet].

PubMed

Schippinger, Michael; Ruckenstuhl, Paul; Friesenbichler, Jörg; Leithner, Andreas

2014-09-01

The World Wide Web has grown during the last years to a considerable source of medical information for experts as well as for laymen and patients. The quality of this information is subjected to some limitation linked with the structure of the Internet and the management of Internet pages. The cross- sectional study presented evaluates and compares quality and reliability of information with respect of osteosarcoma in the most common German-language Internet pages for medical information. As both, one of the most common primary malignant bone tumors and its peak of incidence at the age of childhood and youth, osteosarcoma is considered of significant importance in orthopedic oncology.

Higgs couplings: disentangling new physics with off-shell measurements.

PubMed

Cacciapaglia, Giacomo; Deandrea, Aldo; La Rochelle, Guillaume Drieu; Flament, Jean-Baptiste

2014-11-14

After the discovery of a scalar resonance, resembling the Higgs boson, its couplings have been extensively studied via the measurement of various production and decay channels on the invariant mass peak. Recently, the possibility of using off-shell measurements has been suggested: in particular, the CMS Collaboration has published results based on the high-invariant mass cross section of the process gg→ZZ, which contains a contribution from the Higgs boson. While this measurement has been interpreted as a constraint on the Higgs width after very specific assumptions are taken on the Higgs couplings, in this Letter, we show that a much more model-independent interpretation is possible.

Near-infrared scintillation of xenon by 63Ni beta decay

NASA Astrophysics Data System (ADS)

Yoshimizu, Norimasa; Lal, Amit; Pollock, Clifford R.

2006-07-01

The near-infrared scintillation of xenon gas by the β decay of 37MBq of Ni63 was studied, in the interest of its use in integrated devices for applications such as optical beacons and wavelength calibration. The emission was imaged and analyzed using Spencer's theory of electron penetration using xenon scattering cross sections derived from Thomas-Fermi theory. The total emission was approximately 2×105photons/s at 20kPa and 1×105photons/s at 100kPa. Spectral data show three dominant peaks at 823, 828, and 882nm as well as the formation of metastable states.

Investigation of terbium in the ferroelectric crystal, gadolinium molybdate, as a potential laser

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

Crouch, J.E.

A preliminary non-stimulated study of the laser host combination Gd(2 - x)Tb(x)(MoO4)3 is made. The host material, gadolinium molybdate (GMO), is a ferroelectric/ferroelastic crystal. An investigation of temperature and external electric field affects on the absorption and fluorescence of the crystal did not produce any unusual results. The terbium ion, Tb(3+), peak cross section in GMO for the 5D sub 4 to 7F sub 5 transition is 10 x 10 to the minus twenty first power sq. cm. at 300K. The wavelength of this four level laser transition is 543 nm. (GRA)

Morphology-Dependent Resonances of Spherical Droplets with Numerous Microscopic Inclusions

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.

2014-01-01

We use the recently extended superposition T-matrix method to study the behavior of a sharp Lorenz-Mie resonance upon filling a spherical micrometer-sized droplet with tens and hundreds of randomly positioned microscopic inclusions. We show that as the number of inclusions increases, the extinction cross-section peak and the sharp asymmetry-parameter minimum become suppressed, widen, and move toward smaller droplet size parameters, while ratios of diagonal elements of the scattering matrix exhibit sharp angular features indicative of a distinctly nonspherical particle. Our results highlight the limitedness of the concept of an effective refractive index of an inhomogeneous spherical particle.

Tailoring the dispersion behavior of silicon nanophotonic slot waveguides.

PubMed

Mas, Sara; Caraquitena, José; Galán, José V; Sanchis, Pablo; Martí, Javier

2010-09-27

We investigate the chromatic dispersion properties of silicon channel slot waveguides in a broad spectral region centered at ~1.5 μm. The variation of the dispersion profile as a function of the slot fill factor, i.e., the ratio between the slot and waveguide widths, is analyzed. Symmetric as well as asymmetric geometries are considered. In general, two different dispersion regimes are identified. Furthermore, our analysis shows that the zero and/or the peak dispersion wavelengths can be tailored by a careful control of the geometrical waveguide parameters including the cross-sectional area, the slot fill factor, and the slot asymmetry degree.

Low energy electron-impact ionization of hydrogen atom for coplanar equal-energy-sharing kinematics in Debye plasmas

NASA Astrophysics Data System (ADS)

Li, Jun; Zhang, Song Bin; Ye, Bang Jiao; Wang, Jian Guo; Janev, R. K.

2016-12-01

Low energy electron-impact ionization of hydrogen atom in Debye plasmas has been investigated by employing the exterior complex scaling method. The interactions between the charged particles in the plasma have been represented by Debye-Hückel potentials. Triple differential cross sections (TDCS) in the coplanar equal-energy-sharing geometry at an incident energy of 15.6 eV for different screening lengths are reported. As the screening strength increases, TDCS change significantly. The evolutions of dominant typical peak structures of the TDCS are studied in detail for different screening lengths and for different coplanar equal-energy-sharing geometries.

Ageing and endurance training effects on quantity and quality of pulmonary vascular bed in healthy men

PubMed Central

2014-01-01

It has recently been demonstrated that in healthy individuals, peak oxygen consumption is associated with a greater pulmonary capillary blood volume and a more distensible pulmonary circulation. Our cross-sectional study suggests that, in healthy men aged 20 to 60 years (n = 63), endurance sport practice (vigorous-intensity domain of the International Physical Activity Questionnaire) is associated with better quantity (pulmonary capillary blood volume) and quality (slope of increase in lung diffusion for carbon monoxide on exercise) of the pulmonary vascular bed, partly counterbalancing the deleterious effects of ageing, which remains to be demonstrated in a prospective longitudinal design. PMID:24460636

Further Results on the Production of Neutral Mesons by Photons

DOE R&D Accomplishments Database

Panofsky, W. K. H.; Steinberger, J.; Steller, J.

1951-10-01

Further measurements have been made on the photoproduction of neutral mesons using the gamma-gamma coincidence technique. New data have been obtained on the gamma-gamma correlation curves in beryllium. The angular distribution of the photo mesons in Be has been determined and found to be strongly peaked forward. The dependence on the atomic number A of production has been found to obey an A{sup 2/3} law. Some data obtained for production in hydrogen show that the pi-zero and pi-plus production cross sections are comparable and that the pi-zero excitation curve starts more slowly from threshold than does the pi-plus photo excitation curve.

The flash flood of October 2011 in the Magra River basin (Italy): rainstorm characterisation and flood response analysis

NASA Astrophysics Data System (ADS)

Marchi, Lorenzo; Boni, Giorgio; Cavalli, Marco; Comiti, Francesco; Crema, Stefano; Lucía, Ana; Marra, Francesco; Zoccatelli, Davide

2013-04-01

On 25 October 2011, the Magra River, a stream of northwest Italy outflowing into the Ligurian Sea, was affected by a flash flood, which caused severe economic damage and loss of lives. The catchment covers an area of 1717 km2, of which 605 km2 are drained by the Vara River, the major tributary of the Magra River. The flood was caused by an intense rainstorm which lasted approximately 20 hours. The most intense phase lasted about 8 hours, with rainfall amounts up to around 500 mm. The largest rainfall depths (greater than 300 mm) occurred in a narrow southwest - northeast oriented belt covering an area of approximately 400 km2. This flash flood was studied by analysing rainstorm characteristics, runoff response and geomorphic effects. The rainfall fields used in the analysis are based on data from the Settepani weather radar antenna (located at around 100 km from the study basin) and the local rain gauge network. Radar observations and raingauge data were merged to obtain rainfall estimates at 30 min with a resolution of 1 km2. River stage and discharge rating curves are available for few cross-sections on the main channels. Post-flood documentation includes the reconstruction of peak discharge by means of topographic surveys and application of the slope-conveyance method in 34 cross-sections, observations on the geomorphic effects of the event - both in the channel network and on the hillslopes - and the assessment of the timing of the flood based on interviews to eyewitnesses. Regional authorities and local administrations contributed to the documentation of the flood by providing hydrometeorological data, civil protection volunteers accounts, photos and videos recorded during and immediately after the flood. A spatially distributed rainfall-runoff model, fed with rainfall estimates obtained by the radar-derived observations, was used to check the consistency of field-derived peak discharges and to derive the time evolution of the flood. The assessment of unit peak discharges confirmed the severity of the flood, with values up to approximately 20 m3s-1km-2 in catchments up to 10-20 km2. The strong spatial gradients of the precipitation had a major influence on flood response, with large differences in peak discharge between neighbouring catchments. The magnitude of sediment transport processes, featuring as well a large variability among sub-basins, seems to have been controlled both by peak water discharge and by local geomorphological conditions affecting sediment supply, i.e. occurrence of large landslides connected to the channel network. A striking characteristic of the flood event was the recruitment and transport of large amounts of wood elements, deriving mostly from eroded portions of floodplains and islands along the main channels.

Dust arcs in the region of Jupiter's Trojan asteroids

NASA Astrophysics Data System (ADS)

Liu, Xiaodong; Schmidt, Jürgen

2018-01-01

Aims: The surfaces of the Trojan asteroids are steadily bombarded by interplanetary micrometeoroids, which releases ejecta of small dust particles. These particles form the faint dust arcs that are associated with asteroid clouds. Here we analyze the particle dynamics and structure of the arc in the region of the L4 Trojan asteroids. Methods: We calculate the total cross section of the L4 Trojan asteroids and the production rate of dust particles. The motion of the particles is perturbed by a variety of forces. We simulate the dynamical evolution of the dust particles, and explore the overall features of the Trojan dust arc. Results: The simulations show that the arc is mainly composed of grains in the size range 4-10 microns. Compared to the L4 Trojan asteroids, the dust arc is distributed more widely in the azimuthal direction, extending to a range of [30, 120] degrees relative to Jupiter. The peak number density does not develop at L4. There exist two peaks that are azimuthally displaced from L4.

Two-dimensional explosion experiments examining the interaction between a blast wave and a sand hill

NASA Astrophysics Data System (ADS)

Sugiyama, Y.; Izumo, M.; Ando, H.; Matsuo, A.

2018-05-01

Two-dimensional explosion experiments were conducted to discuss the interaction between a blast wave and sand and show the mitigation effect of the sand on the blast wave. The explosive used was a detonating cord 1.0 m in length, which was initiated in a sand hill shaped like a triangular prism and whose cross section was an isosceles triangle with base angles of 30°. Sand-hill heights of 30 and 60 mm were used as parameters to discuss the effect of sand mass upon blast-wave strength. The interaction of the blast wave with the sand/air interface causes multiple peaks in the blast wave, which are induced by successive transmissions at the interface. The increase in the sand mass further mitigates the blast parameters of peak overpressure and positive impulse. The results of this experiment can be utilized to validate the numerical method of solving the problem of interaction between a compressible fluid and a particle layer.

Two-dimensional explosion experiments examining the interaction between a blast wave and a sand hill

NASA Astrophysics Data System (ADS)

Sugiyama, Y.; Izumo, M.; Ando, H.; Matsuo, A.

2018-02-01

Two-dimensional explosion experiments were conducted to discuss the interaction between a blast wave and sand and show the mitigation effect of the sand on the blast wave. The explosive used was a detonating cord 1.0 m in length, which was initiated in a sand hill shaped like a triangular prism and whose cross section was an isosceles triangle with base angles of 30°. Sand-hill heights of 30 and 60 mm were used as parameters to discuss the effect of sand mass upon blast-wave strength. The interaction of the blast wave with the sand/air interface causes multiple peaks in the blast wave, which are induced by successive transmissions at the interface. The increase in the sand mass further mitigates the blast parameters of peak overpressure and positive impulse. The results of this experiment can be utilized to validate the numerical method of solving the problem of interaction between a compressible fluid and a particle layer.

Beamed neutron emission driven by laser accelerated light ions

NASA Astrophysics Data System (ADS)

Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

2016-05-01

Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ˜ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

Comparing handrim biomechanics for treadmill and overground wheelchair propulsion

PubMed Central

Kwarciak, Andrew M.; Turner, Jeffrey T.; Guo, Liyun; Richter, W. Mark

2010-01-01

Study design Cross-sectional study. Objectives To compare handrim biomechanics recorded during overground propulsion to those recorded during propulsion on a motor-driven treadmill. Setting Biomechanics laboratory. Methods Twenty-eight manual wheelchair users propelled their own wheelchairs, at a self-selected speed, on a low-pile carpet and on a wheelchair accessible treadmill. Handrim biomechanics were recorded with an OptiPush instrumented wheelchair wheel. Results Across the two conditions, all handrim biomechanics were found to be similar and highly correlated (r > 0.85). Contact angle, peak force, average force, and peak axle moment differed by 1.6% or less across the two conditions. While not significant, power output and cadence tended to be slightly higher for the treadmill condition (3.5% and 3.6%, respectively), due to limitations in adjusting the treadmill grade. Conclusion Based on the results of this study, a motor-driven treadmill can serve as a valid surrogate for overground studies of wheelchair propulsion. PMID:21042332