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Sample records for pac perturbed angular

  1. (Perturbed angular correlations in zirconia ceramics)

    SciTech Connect

    Not Available

    1990-01-01

    This is the progress report for the first year of the currently-approved three year funding cycle. We have carried on a vigorous program of experimental and theoretical research on microscopic properties of zirconia and ceria using the Perturbed Angular Correlation (PAC) experimental technique. The experimental method was described in the original proposal and in a number of references as well as several of the technical reports that accompany this progress report.

  2. The mass and angular momentum of reconstructed metric perturbations

    NASA Astrophysics Data System (ADS)

    van de Meent, Maarten

    2017-06-01

    We prove a key result regarding the mass and angular momentum content of linear vacuum perturbations of the Kerr metric obtained through the formalism developed by Chrzarnowski, Cohen, and Kegeles (CCK). More precisely, we prove that the Abbott-Deser mass and angular momentum integrals of any such perturbation vanish when that perturbation was obtained from a regular Fourier mode of the Hertz potential. As a corollary we obtain a generalization of previous results on the completion of the ‘no string’ radiation gauge metric perturbation generated by a point particle. We find that for any bound orbit around a Kerr black hole, the mass and angular momentum perturbations completing the CCK metric are simply the energy and angular momentum of the particle ‘outside’ the orbit and vanish ‘inside’ the orbit.

  3. Atomic jump frequencies in intermetallic compounds studied using perturbed angular correlation of gamma rays

    NASA Astrophysics Data System (ADS)

    Newhouse, Randal Leslie

    Atomic jump frequencies were determined in a variety of intermetallic compounds through analysis of nuclear relaxation of spectra measured using the nuclear hyperfine technique, perturbed angular correlation (PAC) of gamma rays. Observed at higher temperatures, this relaxation is attributed to fluctuations in the orientation or magnitude of electric field gradients (EFG) at nuclei of 111In/Cd probe atoms as the atoms make diffusive jumps. Jump frequencies were obtained by fitting dynamically relaxed PAC spectra using either an empirical relaxation function or using ab initio relaxation models created using the program PolyPacFit. Jump frequency activation enthalpies were determined from measurements over a range of temperatures. Diffusion was studied in the following systems: 1) Pseudo-binary alloys having the L12 crystal structure such as In3(La1-xPrx). The goal was to see how jump frequencies were affected by random disorder. 2) The family of layered phases, LanCoIn3n+2 ( n=0,1,2,3…∞). The goal was to see how jump frequencies varied with the spacing of Co layers, which were found to block diffusion. 3) Phases having the FeGa3 structure. The goal was to analyze dynamical relaxation for probe atoms having multiple inequivalent jump vectors. 4) Phases having the tetragonal Al4Ba structure. The goal was to search for effects in the PAC spectra caused by fluctuations in magnitudes of EFGs without fluctuations in orientations. Ab initio relaxation models were developed to simulate and fit dynamical relaxation for PAC spectra of FeGa3, and several phases with the Al4Ba structure in order to determine underlying microscopic jump frequencies. In the course of this work, site preferences also were observed for 111In/Cd probe atoms in several FeGa 3 and Al4Ba phases.

  4. Stability of Erythrocyte Ghosts: A γ -Ray Perturbed Angular Correlation Study

    NASA Astrophysics Data System (ADS)

    Kruse, Carol A.; Tin, George W.; Baldeschwieler, John D.

    1983-03-01

    The structural integrity of erythrocyte ghosts made by the preswell and slow-dialysis techniques has been studied in vitro by use of γ -ray perturbed angular correlation (PAC) techniques and also by standard in vitro leakage methods employing sequestered labeled markers. Complexes of 111In3+ and nitrilotriacetate were encapsulated in ghosts made from human, rabbit, rat, and mouse erythrocytes, and their leakage was monitored by both methods. In addition, 125I-labeled bovine serum albumin was encapsulated, and ghost integrity was monitored by conventional leakage measurements. With the PAC technique the percentage of material released from human ghosts was determined quantitatively, and the results were equivalent to those obtained by the conventional method. In addition, at various times after intravenous injection, tissue distribution of the ghosts in the mouse was studied. The percent injected dose per gram of tissue of the labeled surface proteins of erythrocyte ghosts in circulation approximated that of the entrapped labeled albumin. This suggests that the ghost membrane and contents are strongly associated in vivo. Large 125I-labeled bovine serum albumin molecules and small 111In3+-nitrilotriacetate complexes were delivered in high quantities to the lung initially, and to the liver and spleen. Because erythrocyte ghosts have the ability to entrap a wide range of substances and deliver them to specific organs, ghosts may be preferable to other drug carriers or drug therapy for treatment of certain disorders.

  5. Contribution from cosmological scalar perturbations to the angular velocity spectrum of extragalactic sources

    SciTech Connect

    Marakulin, A. O. Sazhina, O. S.; Sazhin, M. V.

    2012-07-15

    The possibility of the influence of adiabatic scalar perturbations on the angular velocity spectrum of extragalactic sources is considered. The multipole expansion coefficients of the angular velocity field in terms of vector spherical harmonics are calculated. We show that there is no contribution from adiabatic perturbations to the angular spectrum for a spatially flat Universe at the dusty stage, while there is a contribution only to the electric multiple coefficients at the stage of {Lambda}-term domination. The cases of long-wavelength and short-wavelength perturbations are considered separately. The relationship between the multipole angular velocity spectrum and the primordial scalar perturbation spectrum is discussed.

  6. Atmospheric Phase Correction Using CARMA-PACS: High Angular Resolution Observations of the FU Orionis Star PP 13S*

    NASA Astrophysics Data System (ADS)

    Pérez, Laura M.; Lamb, James W.; Woody, David P.; Carpenter, John M.; Zauderer, B. Ashley; Isella, Andrea; Bock, Douglas C.; Bolatto, Alberto D.; Carlstrom, John; Culverhouse, Thomas L.; Joy, Marshall; Kwon, Woojin; Leitch, Erik M.; Marrone, Daniel P.; Muchovej, Stephen J.; Plambeck, Richard L.; Scott, Stephen L.; Teuben, Peter J.; Wright, Melvyn C. H.

    2010-11-01

    We present 0farcs15 resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best-fit model corresponds to 0.06 M sun, which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability.

  7. ATMOSPHERIC PHASE CORRECTION USING CARMA-PACS: HIGH ANGULAR RESOLUTION OBSERVATIONS OF THE FU ORIONIS STAR PP 13S*

    SciTech Connect

    Perez, Laura M.; Carpenter, John M.; Isella, Andrea; Lamb, James W.; Woody, David P.; Leitch, Erik M.; Muchovej, Stephen J.; Scott, Stephen L.; Zauderer, B. Ashley; Bolatto, Alberto D.; Teuben, Peter J.; Bock, Douglas C.; Carlstrom, John; Culverhouse, Thomas L.; Marrone, Daniel P.; Joy, Marshall; Kwon, Woojin; Plambeck, Richard L.; Wright, Melvyn C. H.

    2010-11-20

    We present 0.''15 resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best-fit model corresponds to 0.06 M{sub sun}, which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability.

  8. Mediolateral angular momentum changes in persons with amputation during perturbed walking.

    PubMed

    Sheehan, Riley C; Beltran, Eduardo J; Dingwell, Jonathan B; Wilken, Jason M

    2015-03-01

    Over 50% of individuals with lower limb amputation fall at least once each year. These individuals also exhibit reduced ability to effectively respond to challenges to frontal plane stability. The range of whole body angular momentum has been correlated with stability and fall risk. This study determined how lateral walking surface perturbations affected the regulation of whole body and individual leg angular momentum in able-bodied controls and individuals with unilateral transtibial amputation. Participants walked at fixed speed in a Computer Assisted Rehabilitation Environment with no perturbations and continuous, pseudo-random, mediolateral platform oscillations. Both the ranges and variability of angular momentum for both the whole body and both legs were significantly greater (p<0.001) during platform oscillations. There were no significant differences between groups in whole body angular momentum range or variability during unperturbed walking. The range of frontal plane angular momentum was significantly greater for those with amputation than for controls for all segments (p<0.05). For the whole body and intact leg, angular momentum ranges were greater for patients with amputation. However, for the prosthetic leg, angular momentum ranges were less for patients than controls. Patients with amputation were significantly more affected by the perturbations. Though patients with amputation were able to maintain similar patterns of whole body angular momentum during unperturbed walking, they were more highly destabilized by the walking surface perturbations. Individuals with transtibial amputation appear to predominantly use altered motion of the intact limb to maintain mediolateral stability.

  9. Mediolateral Angular Momentum Changes in Persons With Amputation During Perturbed Walking✰

    PubMed Central

    Sheehan, Riley C.; Beltran, Eduardo J.; Dingwell, Jonathan B.; Wilken, Jason M.

    2015-01-01

    Over 50% of individuals with lower limb amputation fall at least once each year. These individuals also exhibit reduced ability to effectively respond to challenges to frontal plane stability. The range of whole body angular momentum has been correlated with stability and fall risk. This study determined how lateral walking surface perturbations affected the regulation of whole body and individual leg angular momentum in able-bodied controls and individuals with unilateral transtibial amputation. Participants walked at fixed speed in a Computer Assisted Rehabilitation ENvironment with no perturbations and continuous, pseudo-random, mediolateral platform oscillations. Both the ranges and variability of angular momentum for both the whole body and both legs were significantly greater (p < 0.001) during platform oscillations. There were no significant differences between groups in whole body angular momentum range or variability during unperturbed walking. The range of frontal plane angular momentum was significantly greater for those with amputation than for controls for all segments (p < 0.05). For the whole body and intact leg, angular momentum ranges were greater for patients with amputation. However, for the prosthetic leg, angular momentum ranges were less for patients than controls. Patients with amputation were significantly more affected by the perturbations. Though patients with amputation were able to maintain similar patterns of whole body angular momentum during unperturbed walking, they were more highly destabilized by the walking surface perturbations. Individuals with transtibial amputation appear to predominantly use altered motion of the intact limb to maintain mediolateral stability. PMID:25797789

  10. Cd hyperfine interactions in DNA bases and DNA of mouse strains infected with Trypanosoma cruzi investigated by perturbed angular correlation spectroscopy and ab initio calculations.

    PubMed

    Petersen, Philippe A D; Silva, Andreia S; Gonçalves, Marcos B; Lapolli, André L; Ferreira, Ana Maria C; Carbonari, Artur W; Petrilli, Helena M

    2014-06-03

    In this work, perturbed angular correlation (PAC) spectroscopy is used to study differences in the nuclear quadrupole interactions of Cd probes in DNA molecules of mice infected with the Y-strain of Trypanosoma cruzi. The possibility of investigating the local genetic alterations in DNA, which occur along generations of mice infected with T. cruzi, using hyperfine interactions obtained from PAC measurements and density functional theory (DFT) calculations in DNA bases is discussed. A comparison of DFT calculations with PAC measurements could determine the type of Cd coordination in the studied molecules. To the best of our knowledge, this is the first attempt to use DFT calculations and PAC measurements to investigate the local environment of Cd ions bound to DNA bases in mice infected with Chagas disease. The obtained results also allowed the detection of local changes occurring in the DNA molecules of different generations of mice infected with T. cruzi, opening the possibility of using this technique as a complementary tool in the characterization of complicated biological systems.

  11. A Investigation of the Bleomycin-Dna Interaction Using Perturbed Angular Correlations.

    NASA Astrophysics Data System (ADS)

    Hallee, Gary John

    Perturbed angular correlations (PAC) of the 173 keV-247 keV gamma-gamma cascade in the decay of ('111)In offers a sensitive new approach to probe biological molecules in aqueous solution. We have found that this method can be effectively utilized to study the interaction of anti -tumor drug molecules such as bleomycin, which chelate ('111)In('3+), with double helical DNA. For the small ('111)In-BLM complex, the time-integrated attenuation factor G(,2)(' )=(' )0.40, and when ('111)In-BLM is specifically bound to the large and sluggish DNA molecule, we have G(,2)(' )=(' )0.20 for ('111)In-BLM-DNA. Using these two extreme values as signatures of free and DNA-bound bleomycin fractions, we have studied the binding of BLM to various types of DNA. Binding curves for calf thymus DNA, and poly dA-dT are presented. The size of FLM binding site was determined to be 3.3 base pairs for calf thymus DNA, and 2.5 base pairs for poly dA-dT. These results and association constants compare well with results based on other biochemical methods, such as fluorescence quenching. A highly cooperative interaction of BLM with poly dA-dT was observed, but no evidence of cooperativity was seen in the case of calf thymus DNA. In addition, studies of salt-dependence of the binding revealed cooperative behavior in the case of poly dA-dT, and the covalently closed super-helical DNA of PM-2 bacteriophage, but not for calf thymus DNA. Soft modes of DNA under premelting conditions are suggested to be the likely reason for observed cooperativity in the case of poly dA-dT under the low Na('+) concentrations (<(, )10 mM) involved. In the case of calf thymus DNA, a thermodynamic analysis of ionic effects indicates that 1.2 counter ions are released per BLM molecule bound. Other studies revealed relatively weak binding of ('111)In-BLM to yeast RNA, and a likely conformational change in ('111)In -BLM brought about by the action of dethiothreitol.

  12. Indium donor/metal vacancy defect complexes in cadmium telluride studied with perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Griffith, John Warren

    Semi-insulating, powder samples of Cadmium Telluride (CdTe) have been studied using 111In Time Differential Perturbed Angular Correlation (PAC) Spectroscopy. The samples have been lightly doped (˜10 12 cm-3) with 111In atoms, which occupy well-defined metal (Cd) lattice sites and act as probes of the local environment. These substitutional donors form a single defect complex in CdTe. This complex has been identified and characterized as a function of temperature. Those indium probes that are not complexed occupy metal lattice sites with no defect in the local vicinity. Samples containing metal vacancy concentrations as large as 500 ppm have been prepared by a high temperature anneal and quench. The defect complex involves the trapping of a cadmium metal vacancy bound to the indium probe. The electric field gradient (EFG) experienced by probe atoms has a coupling constant of nuQ = 61.5(5) MHz and is not axially symmetric, with the asymmetry parameter given by eta = 0.16(4). It is believed that this asymmetry results from a relaxation of the chalcogen (Te) atoms adjacent to the metal vacancy, with the tellurium atom shared by the probe atom and the vacancy providing the dominant contribution. The fraction of complexed probe atoms increases as the sample temperature is decreased, and is still increasing at room temperature. Complexed fractions are reproducible on cycling within the temperature range 40 to 200°C. The binding energy of the complex has been measured to be 0.15(2) eV and is independent of metal vacancy concentration, which varies and is dependent on the details of the quench. In rapidly cooled samples, a non-equilibrium number of these defect complexes is observed. This state equilibrates with a time constant of 45(5) hours at 15°C, implying that at least one of the two constituents involved in the complex has a significant diffusion rate at this temperature. Under the assumption that vacancy diffusion mechanisms dominate at this temperature, it is

  13. Linear force and moment equations for an annular smooth shaft seal perturbed both angularly and laterally

    NASA Technical Reports Server (NTRS)

    Fenwick, J.; Dijulio, R.; Ek, M. C.; Ehrgott, R.

    1982-01-01

    Coefficients are derived for equations expressing the lateral force and pitching moments associated with both planar translation and angular perturbations from a nominally centered rotating shaft with respect to a stationary seal. The coefficients for the lowest order and first derivative terms emerge as being significant and are of approximately the same order of magnitude as the fundamental coefficients derived by means of Black's equations. Second derivative, shear perturbation, and entrance coefficient variation effects are adjudged to be small.

  14. pH-dependent structural change of reduced spinach plastocyanin studied by perturbed angular correlation of gamma-rays and dynamic light scattering.

    PubMed

    Sas, Klára Nárcisz; Haldrup, Anna; Hemmingsen, Lars; Danielsen, Eva; Øgendal, Lars Holm

    2006-06-01

    In this study the pH-dependent structural changes of reduced spinach plastocyanin were investigated using perturbed angular correlation (PAC) of gamma-rays and dynamic light scattering (DLS). PAC data of Ag-substituted plastocyanin indicated that the coordinating ligands are two histidine residues (His37, His87) and a cysteine residue (Cys84) in a planar configuration, whereas the methionine (Met92) found perpendicular to this plane is not a coordinating ligand at neutral pH. Two slightly different conformations with differences in the Cys-metal ion-His angles could be observed with PAC spectroscopy. At pH 5.3 a third coordination geometry appears which can be explained as the absence of the His87 residue and the coordination of Met92 as a ligand. With DLS the aggregation of reduced plastocyanin could be observed below pH 5.3, indicating that not only the metal binding site but also the aggregation properties of the protein change upon pH reduction. Both the structural changes at the metal binding site and the aggregation are shown to be reversible. These results support the hypothesis that the pH of the thylakoid lumen has to remain moderate during steady-state photosynthesis and indicate that low pH induced aggregation of plastocyanin might serve as a regulatory switch for photosynthesis.

  15. Growth of Ga2O3 by furnace oxidation of GaN studied by perturbed angular correlations

    NASA Astrophysics Data System (ADS)

    Steffens, Michael; Vianden, Reiner; Pasquevich, Alberto F.

    2016-12-01

    Ga2O3 is a promising material for use in "solar-blind" UV-detectors which can be produced efficiently by oxidation of GaN. In this study we focus on the evolution of the oxide layer when GaN is heated in air. The experimental method applied is the perturbed angular correlation (PAC) spectroscopy of γ-rays emitted by radioactive nuclides, here 111Cd and 181Ta, whose parent nuclei are ion implanted into films of GaN grown on sapphire. As the emission pattern for nuclei in GaN is clearly distinct from that of nuclei in Ga2O3, the fraction of probe nuclei in the oxide layer can be directly measured and allows to follow the time dependent growth of the oxide on a scale of less than 100 nm. Additional measurements were carried out with the oxidized sample held at fixed temperatures in the temperature range from 19 K to 973 K showing transitions between the hyperfine interactions of 111Cd in the oxide matrix both at high and low temperatures. A model for these transitions is proposed.

  16. Low temperature structural modification in Rb2ZrF6: Investigations by perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Dey, S. K.; Dey, C. C.; Saha, S.

    2016-06-01

    Temperature dependent perturbed angular correlation (PAC) measurements in crystalline compounds Rb2ZrF6 and Cs2HfF6 have been performed in the temperature range 298-753 K. In Rb2ZrF6, four discrete quadrupole interaction frequencies have been observed at room temperature which correspond to four minor structural modifications. From previous measurements, on the other hand, two structural modifications of this compound were known. A displacive phase transition, probably, occurs at low temperature due to rotation of the ZrF62- octahedron and produces different structural modifications. From present measurements in Rb2ZrF6, two quadrupole interaction frequencies [ωQ=26.1(3) Mrad/s, η=0.55(2), δ=5(1)% and ωQ=148.7(3) Mrad/s, η=0.538(5), δ=1.2%] have been found at room temperature which were not found from previous studies. In Cs2HfF6, these new structural modifications have not been observed.

  17. Static Magnetic Properties of Films Measured by Means of Angular Perturbative Magnetoresistance

    NASA Astrophysics Data System (ADS)

    Oliveira, Alexandre; Melo, Abner; da Costa, Ricardo; Chesman, Carlos

    In this work we introduced a new technique to measure magnetic anisotropies and magnetoelectrical properties, such as Anisotropic Magnetoresistance (AMR) and Giant Magnetoresistance (GMR) amplitudes. The Perturbative Magnetoresistance (PMR) consist of a regular collinear four probe magnetoresistance set up with an AC magnetic field (hac) applied perpendicular to the DC (Hdc) one. hac amplitude is about 1.0 Oe and oscillate at 270 Hz. We successfully interpreted the signal response from the voltage measured by lock-in amplifier and proposed a model based on energy minimization to extract magnetic anisotropies, AMR and GMR amplitudes. Measuring the in-plane angular dependency of PMR signal we were able to identify the usual magnetic anisotropy, such as uniaxial, unidirectional and cubic. Taking into account the perturbative nature of this technique (small hac amplitude and low frequency), we argue that angular PMR can be used to investigate some dynamic magnetic effects where static technique can not provide such information. A distinct feature of angular PMR is the capability to be used in saturated and non-saturated regime, so revealing magnetic properties dependency on applied field strength. We addressed the Rotatable Anisotropy as an example in this work.

  18. Second order classical perturbation theory for atom surface scattering: Analysis of asymmetry in the angular distribution

    SciTech Connect

    Zhou, Yun Pollak, Eli; Miret-Artés, Salvador

    2014-01-14

    A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to “soft” corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.

  19. Dynamic stability of rotating flexible disk perturbed by the reciprocating angular movement of suspension-slider system

    NASA Astrophysics Data System (ADS)

    Pei, Yong-Chen; Tan, Qing-Chang; Zheng, Fu-Sheng; Zhang, Yong-Qi

    2010-12-01

    To simulate the dynamic process of a magnetic head reading/writing data in a hard disk drive, a rotating flexible thin disk perturbed by the reciprocating angular movement of a suspension-slider system is modelled, where the suspension-slider system is considered as a mass-damping-spring loading system. A system dynamic model is formulated as a parametrically excited system, and its dynamic stability is studied by Hill's method involving harmonic balance. The reciprocating angular movement of the suspension-slider system causes system parametric instability at some angular movement frequencies. The large-amplitude angular movement is especially dangerous, and angular movement frequency must be reduced when the slider works at large radii of the disk. The parametric instability can be avoided or suppressed by operating at: low-frequency and small-amplitude reciprocating angular movement, small mass, large natural frequency and damping of the suspension-slider system, and low-speed rotation of the disk.

  20. Hafnium oxide thin films studied by time differential perturbed angular correlations

    NASA Astrophysics Data System (ADS)

    Dey, C. C.; Dey, S.; Bedi, S. C.; Das, S. K.; Lorenz, M.; Grundmann, M.; Vogt, J.; Butz, T.

    2011-06-01

    We report on the study of hafnium oxide thin films grown by pulsed laser deposition at various partial oxygen pressures by Time Differential Perturbed Angular Correlations using the nuclear probe 181Hf(β-)181Ta to determine the nuclear quadrupole interaction (NQI), and by x-ray diffraction. The samples were neutron activated and measured at room temperature as received as well as after annealing in air. All spectra exhibited two to three inequivalent probe sites, even after annealing. At 0.3 mbar oxygen partial pressure and annealing for 5 hs at 1073 K the majority (88%) of the sites exhibited NQI parameters as reported for the bulk monoclinic phase [ωQ = 125.4(2) Mrad/s, η = 0.335(5)]. We can exclude amorphous as well as cubic and tetragonal hafnium oxide phases in the annealed samples. There was no indication of room-temperature ferromagnetism.

  1. On angularly perturbed Laplace equations in the unit ball of IR{sup n+2} and their distributional boundary values

    SciTech Connect

    Massopust, P.R.

    1997-08-01

    All solutions of an in its angular coordinates continuously perturbed Laplace-Beltrami equation in the open unit ball IB{sup n+2} {contained_in} IR{sup n+2}, n {ge} 1, are characterized. Moreover, it is shown that such pertubations yield distributional boundary values which are different from, but algebraically and topologically equivalent to, the hyperfunctions of Lions & Magenes. This is different from the case of radially perturbed Laplace-Beltrami operators (cf. [7]) where one has stability of distributional boundary values under such perturbations.

  2. Angular velocity perturbations inducing the Papaloizou-Pringle instability and QPOs in the torus around the black hole

    NASA Astrophysics Data System (ADS)

    Donmez, Orhan

    2017-06-01

    In this paper, a numerical study of the dynamic of the non-self-gravitating, unmagnetized, non-axisymmetric, and rotating the torus around the non-rotating black hole is presented. We investigate the instability of the rotating torus subject to perturbations presented by increasing or decreasing the angular velocity of the stable torus. We have done, for the first time, an extensive analysis of the torus dynamic response to the perturbation of the angular velocity of the stable torus. We show how the high, moderate, and low values of the perturbations affect the torus dynamic and help us to understand the properties of the instability and quasi-periodic oscillation (QPO). Our numerical simulations indicate the presence of Papaloizou-Pringle instability (PPI) with global m = 1 mode and QPOs for the moderate and lower values of the perturbations on the angular velocity of the stable torus. Furthermore, with the lower values of the perturbations, the torus can lead to a wiggling initially and then PPI is produced in it. Finally, the matter of the torus would be dissipated due to the presence of a strong torque.

  3. Electric field gradients at 181Ta probe in ZrNi: Results from perturbed angular correlation and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Dey, C. C.; Das, Rakesh; Srivastava, S. K.

    2015-07-01

    Results of temperature dependent perturbed angular correlation (PAC) measurements in the equiatomic ZrNi alloy have been reported for the first time using 181Hf probe. At room temperature, values of quadrupole frequency and asymmetry parameter for the major component (~80%) are found to be ωQ=26.8(4) Mrad/s, and η=0.413(7). The resulting electric field gradient comes out to be Vzz=2.99 ×1017 V/cm2 and this corresponds to the probe nuclei occupying the regular substitutional Zr sites. In ZrNi system, no magnetic interaction is observed down to 77 K indicating absence of any magnetism in this material. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies on an inactive but similarly prepared sample confirm the dominant presence of the orthorhombic ZrNi phase in the sample. A complementary density functional theory (DFT) calculation results in Vzz=-2.35×1017 V/cm2, η=0.46 at the 181Ta probe impurity site and zero magnetic moment on each atomic site, in close agreement with the experimental results. Furthermore, it is found that electric field gradient for the regular component follows a T3/2 temperature dependence between 77 and 353 K, beyond which it varies linearly with temperature.

  4. Second-Order Perturbation Formula for Magnetocrystalline Anisotropy Using Orbital Angular Momentum Matrix

    NASA Astrophysics Data System (ADS)

    Kosugi, Taichi; Miyake, Takashi; Ishibashi, Shoji

    2014-04-01

    We derive a second-order perturbation formula for an electronic system subject to spin-orbit interactions (SOI). The energy correction originates in the spin-conserving and the spin-flip transitions. The former are represented by the orbital angular momentum (OAM) acquired via the SOI. The latter come from the quantum fluctuation effect. By using our formula, we examine the relativistic electronic structures of a d orbital chain and L10 alloys. The appearance of OAM in the chain is understood by using a parabolic-bands model and the exact expressions of the single-particle states. The total energy is found to be accurately reproduced by the formula. The self-consistent fully relativistic first-principles calculations based on the density functional theory are performed for five L10 alloys. It is found that the formula reproduces qualitatively the behavior of their exact magnetocrystalline anisotropy (MCA) energies. While the MCA of FePt, CoPt, and FePd originates in the spin-conserving transitions, that in MnAl and MnGa originates in the spin-flip contributions. For FePt, CoPt, and FePd, the tendency of the MCA energy with the variation in the lattice constant obeys basically that of the spin-flip contributions. These results indicate that not only the anisotropy of OAM, but also that of spin-flip contributions must be taken into account for the understanding of the MCA of the L10 alloys.

  5. Electric field gradients of CeMIn5 (M= Co, Rh, Ir) heavy-fermion systems studied by perturbed angular correlations and ab initio electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Forker, M.; Silva, P. R. J.; Cavalcante, J. T. P. D.; Cavalcante, F. H. M.; Ramos, S. M.; Saitovitch, H.; Baggio-Saitovitch, E.; Alonso, R.; Taylor, M.; Errico, L. A.

    2013-04-01

    The electric field gradient (EFG) at the highly dilute nuclear probe 111Cd in the heavy fermion systems CeMIn5, M= Co, Rh, and Ir and YCoIn5 has been investigated by perturbed angular correlation (PAC) measurements of the nuclear electric quadrupole interaction (QI) of 111Cd on In sites. Pure and Sn-doped single crystals prepared by In-flux synthesis and polycrystalline samples prepared by arc melting have been studied. The samples were doped with the PAC probe 111Cd by diffusion of the mother isotope 111In. In all samples, several fractions of 111Cd probe nuclei subject to different QI's have been observed, among them a large fraction of 111Cd in unreacted In metal. Detailed calculations of the EFG at In nuclei and at Cd probes on In sites of pure and Sn-doped CeMIn5 were preformed, using the full-potential augmented plane wave+local orbital (APW+lo) formalism and taking into account different variables such as the electronic structure of the hyperfine probes, probe induced structural distortions, and impurity doping. The excellent agreement between the predicted EFG's and the experimental results allows us to assign two of the observed EFG components to the lattice sites 1c and 4i of the CeMIn5 compounds and to explain the pronounced difference of the EFG at In and Cd probes on the same lattice position. Structural distortions induced by the Cd probe and Sn-doping were found to have little effect on the EFG at the Cd probes. We also show that the local spin density approximation (LSDA) and LDA+U calculations predict very similar equilibrium structures and EFG's at the In/Cd sites. The extension of the experiments and the calculations from CeMIn5 to YCoIn5 and LaCoIn5 have established that the influence of the 4f electrons on the EFG's at impurity sites is negligibly small.

  6. Effect of Ge substitution for Si on the magnetic hyperfine field in LaMn2Si2 compound measured by perturbed angular correlation spectroscopy with 140Ce as probe nuclei

    NASA Astrophysics Data System (ADS)

    Bosch-Santos, B.; Carbonari, A. W.; Cabrera-Pasca, G. A.; Costa, M. S.; Saxena, R. N.

    2013-05-01

    The effect of substitution of Ge for Si in LaMn2Si2 compound on the magnetic hyperfine field (Bhf) has been investigated by perturbed γ -γ angular correlation (PAC) spectroscopy using 140La(140Ce) as probe nuclei. This compound exhibits antiferromagnetism followed by a ferromagnetic ordering when temperature decreases. The behavior of the ferromagnetic transition when Ge gradually replaces Si, with concentrations of 20%, 40%, 80%, and 100% is discussed. PAC measurements were carried out in the temperature range from 15 K to 325 K. Results for LaMn2Si2 compound showed that the dependence of Bhf with temperature follows the expected behavior for the host magnetization and could be fitted by a Brillouin function for JMn = 5/2. However, the temperature dependence of Bhf for compounds when Si is gradually replaced by Ge showed a deviation from such a behavior, which gradually increases up to a strong deviation observed for LaMn2Ge2. This striking behavior was ascribed to the hybridization of d band of the host and f band of the Ce impurities, which is stronger when the unit cell volume increase as Si ions are substituted by Ge atoms.

  7. Low energy γ- γ and e -- γ PAC measurements using APDs and the probe nuclei 83Rb(83Kr) and 83 m Kr(83Kr)

    NASA Astrophysics Data System (ADS)

    Arenz, M.; Vianden, R.

    2016-12-01

    In the field of Perturbed Angular Correlation (PAC) measurements Avalanche Photo Diodes (APD) are rarely used, despite their favourable properties for fast counting purposes at low energies. This work demonstrates their application in combination with a simple and cheap custom build voltage sensitive preamplifier module. Using the PAC nuclei 83Rb(83Kr) and 83mKr(83Kr), the time resolution of the set-up is analysed and the feasibility of precise timing measurements is shown.

  8. In vivo Stability of Ester- and Ether-Linked Phospholipid-Containing Liposomes as Measured by Perturbed Angular Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Derksen, Johannes T.; Baldeschwieler, John D.; Scherphof, Gerrit L.

    1988-12-01

    To evaluate liposome formulations for use as intracellular sustained-release drug depots, we have compared the uptake and degradation in rat liver and spleen of liposomes of various compositions, containing as their bulk phospholipid an ether-linked phospholipid or one of several ester-linked phospholipids, by perturbed angular correlation spectroscopy. Multilamellar and small unilamellar vesicles (MLVs and SUVs), composed of egg phosphatidylcholine, sphingomyelin, distearoyl phosphatidylcholine (DSPC), dipalmitoyl phosphatidylcholine (DPPC) or its analog dihexadecylglycerophosphorylcholine (DHPC), and cholesterol plus phosphatidylserine, and containing 111In complexed to nitrilotriacetic acid, were injected intravenously in rats. Recovery of 111In-labeled liposomes in blood, liver, and spleen was assessed at specific time points after injection and the percentage of liposomes still intact in liver and spleen was determined by measurement of the time-integrated angular perturbation factor 111In of the [G22(∞ )] label. We found that MLVs but not SUVs, having DHPC as their bulk phospholipid, showed an increased resistance against lysosomal degradation as compared to other phospholipid-containing liposomes. The use of diacyl phospholipids with a high gel/liquid-crystalline phase-transition temperature, such as DPPC and DSPC, also retarded degradation of MLV, but not of SUV in the dose range tested, while the rate of uptake of these liposomes by the liver was lower.

  9. In vivo stability of ester- and ether-linked phospholipid-containing liposomes as measured by perturbed angular correlation spectroscopy.

    PubMed Central

    Derksen, J T; Baldeschwieler, J D; Scherphof, G L

    1988-01-01

    To evaluate liposome formulations for use as intracellular sustained-release drug depots, we have compared the uptake and degradation in rat liver and spleen of liposomes of various compositions, containing as their bulk phospholipid an ether-linked phospholipid or one of several ester-linked phospholipids, by perturbed angular correlation spectroscopy. Multilamellar and small unilamellar vesicles (MLVs and SUVs), composed of egg phosphatidylcholine, sphingomyelin, distearoyl phosphatidylcholine (DSPC), dipalmitoyl phosphatidylcholine (DPPC) or its analog dihexadecylglycerophosphorylcholine (DHPC), and cholesterol plus phosphatidylserine, and containing 111In complexed to nitrilotriacetic acid, were injected intravenously in rats. Recovery of 111In-labeled liposomes in blood, liver, and spleen was assessed at specific time points after injection and the percentage of liposomes still intact in liver and spleen was determined by measurement of the time-integrated angular perturbation factor [G22(infinity)] of the 111In label. We found that MLVs but not SUVs, having DHPC as their bulk phospholipid, showed an increased resistance against lysosomal degradation as compared to other phospholipid-containing liposomes. The use of diacyl phospholipids with a high gel/liquid-crystalline phase-transition temperature, such as DPPC and DSPC, also retarded degradation of MLV, but not of SUV in the dose range tested, while the rate of uptake of these liposomes by the liver was lower. PMID:3200855

  10. Angular redistribution of nonlinear perturbations: a universal feature of nonuniform flows.

    PubMed

    Horton, W; Kim, J-H; Chagelishvili, G D; Bowman, J C; Lominadze, J G

    2010-06-01

    Classically, the net action of nonlinear turbulent processes is interpreted as either a direct or inverse cascade. However, in nonuniform/shear flows the dominant process is a nonlinear redistribution over wave number angle of perturbation spatial Fourier harmonics. We call this process a nonlinear transverse redistribution (NTR). This phenomenon is demonstrated for a simple two-dimensional constant shear (non-normal) flow by numerically simulating the nonlinear dynamics of coherent and stochastic vortical perturbations in the flow. NTR is a general feature of nonlinear processes that should manifest itself in nonuniform engineering, environmental, and astrophysical flows. The conventional characterization of turbulence in terms of direct and inverse cascades, which ignores NTR, appears to be misleading for shear flow turbulence. We focus on the action of nonlinear processes on the spectral energy. NTR redistributes perturbations over different quadrants of the wave number plane and the interplay of this nonlinear redistribution with linear phenomena becomes intricate: it can realize either positive or negative feedback. In the case of positive feedback, it repopulates the quadrants in wave number space where the shear flow induces linear transient growth.

  11. Indirect perturbation influence of planets on the variation of the instantaneous angular velocity of the rigid Earth in the lunar-solar gravitational field

    NASA Astrophysics Data System (ADS)

    Li, Lin-Sen

    2017-08-01

    The differential equation and its solution for indirect influence of the planetary perturbation on the variation of the rotational angular velocity of the rigid Earth in the lunar-solar gravitational field are obtained by using Euler's dynamic equations. The theoretical results show that the angular velocity of the Earth varies with the periodic and mixed periodic variation under the lunar and solar gravitational field due to the planetary perturbation on the Earth orbit. The numerical results for the amplitudes of the periodic terms and the coefficient of the mixed periodic terms are presented.

  12. A compact digital time differential perturbed angular correlation-spectrometer using field programmable gate arrays and various timestamp algorithms

    SciTech Connect

    Jaeger, Markus; Butz, Tilman; Iwig, Kornelius

    2011-06-15

    A user-friendly fully digital time differential perturbed angular correlation (TDPAC)-spectrometer with six detectors and fast digitizers using field programmable gate arrays (FPGA) is described and performance data are given. The new spectrometer has an online data analysis feature, a compact size, and a time resolution such as conventional analog spectrometers. Its calculation intensive part was implemented inside the digitizer. This gives the possibility to change parameters (energy windows, constant fraction trigger delay) and see their influence immediately in the {gamma}-{gamma} correlation diagrams. Tests were performed which showed that the time resolution using a {sup 60}Co source with energy window set at 1.17 MeV and 1.33 MeV is 265 ps with LaBr{sub 3}(Ce) scintillators and 254 ps with BaF{sub 2} scintillators. A true constant fraction algorithm turned out to be slightly better than the constant fraction of amplitude method. The spectrometer performance was tested with a TDPAC measurement using a {sup 44}Ti in rutile source and a positron lifetime measurement using {sup 22}Na. The maximum possible data rate of the spectrometer is 1.1 x 10{sup 6} {gamma} quanta per detector and second.

  13. Overview of PACS

    NASA Astrophysics Data System (ADS)

    Vanden Brink, John A.

    1995-08-01

    Development of the DICOM standard and incremental developments in workstation, network, compression, archiving, and digital x-ray technology have produced cost effective image communication possibilities for selected medical applications. The emerging markets include modality PACS, mini PACS, and teleradiology. Military and VA programs lead the way in the move to adopt PACS technology. Commercial markets for PACS components and PAC systems are at LR400 million growing to LR500 million in 1996.

  14. PAC and XPS studies of II-VI compounds

    NASA Astrophysics Data System (ADS)

    Swanson, M. L.; Hughes, W. C.; Austin, J. C.; Choi, S. S.

    The perturbed angular correlation (PAC) method has considerable potential for studying near-surface defects of materials on a microscopic scale, especially in combination with standard surface techniques. We have characterized the near-surface and surface regions of II-VI compounds using PAC and X-ray photoelectron spectroscopy (XPS). PAC was used to identify point defect complexes containing the radioactive In-111 probe atoms, which were diffused into Cd(0.96)Zn(0.04)Te, Cd(0.8)Mn(0.2)Te, and Hg(0.79)Cd(0.21)Te (MCT) samples under vacuum from 200 to 550 C. After the Cd(Zn)Te samples were annealed at 450 C for 30 min, 60% of the In atoms occupied unique non-cubic sites, characterized by an interaction frequency Nu(sub Q) = 60 MHz and an asymmetry parameter eta = 0.2. These sites were attributed to In-(cadmium vacancy) complexes, since this signal was eliminated by subsequent annealing in a cadmium atmosphere. Similar results were obtained for the Cd(Mn)Te samples, but the vacancy complex occurred at a lower annealing temperature. The XPS data for Cd(Mn)Te showed that its oxide characteristics differed considerably from those of CdTe. Although oxide formation of CdTe occurs very lowly after sputter cleaning, a significant Te-O layer was formed on the Cd(Mn)Te surfaces after only 10 min exposure to air. In addition, deionized water removed the native oxide completely for CdTe but not for Cd(Mn)Te. For MCT, annealing at 350 C caused the formation of two defect complexes, characterized by frequencies of 83 and 92 MHz, and eta is approximately equal 0.1. These PAC signals vanished after annealing under a mercury atmosphere, indicating that they were also due to In-vacancy complexes.

  15. Magnetic behavior of La-doped Fe{sub 3}O{sub 4} studied by perturbed angular correlation spectroscopy with {sup 111}Cd and {sup 140}Ce

    SciTech Connect

    Matos, I. T. Bosch-Santos, B.; Cabrera-Pasca, G. A.; Carbonari, A. W.

    2015-05-07

    In this paper, the local magnetic properties of La-doped Fe{sub 3}O{sub 4} (5% and 10%) bulk and Nanoparticles (NPs) samples were studied by measuring hyperfine interactions in a wide range of temperature from 10 to 900 K with perturbed γ-γ angular correlation spectroscopy using {sup 111}In({sup 111}Cd) and {sup 140}La({sup 140}Ce) as probe nuclei. Results for the temperature dependence of the magnetic hyperfine field (B{sub hf}) for bulk and NP samples, pure and doped with La show that its behavior follows a second order Brillouin-like transition from which the Curie temperature (T{sub C}) was determined (T{sub C} ∼ 855 K). Results also show two different regions in NP samples: the core where a minor fraction of probe nuclei with well defined magnetic dipole frequency was observed and the shell where a major fraction with broad distributed electric quadrupolar frequency (surface effect in NP) was observed. The Verwey transition T{sub V} ∼ 120 K, due the order disorder phase, was also observed in all samples. The results are discussed in terms of the magnetic exchange interaction between Fe{sup 2+} and Fe{sup 3+} ions in the two regions of NP.

  16. Studies of interaction between He and elements with mass number 140 in Fe by time-differential perturbed-angular-correlation measurements

    NASA Astrophysics Data System (ADS)

    Ohkubo, Yoshitaka; Taniguchi, Akihiro; Xu, Qiu; Tanigaki, Minoru; Sato, Koichi

    2014-08-01

    Room-temperature time-differential perturbed-angular-correlation (TDPAC) spectra of 140Ce arising through 140Ba-140La from 140Cs in He-doped Fe, unannealed and annealed in vacuum at various temperatures, were obtained in order to examine whether Ce (or rather, La and Ba) and He form complexes having a definite geometrical structure in Fe, as suggested by first-principles density-functional theory calculations. No clear signal of such complexes was observed in the TDPAC spectra. However, the TDPAC spectra indicate that Ce and He form complexes having a variety of geometrical structures. Comparison with reported TDPAC results on 111Cd arising from 111In in He-doped stainless steel shows that the parent atoms (La and Ba) of 140Ce trap He atoms more efficiently than In atoms do, indicating stronger bonding of He to the former atoms, while different from the present case, 111Cd (In)-He complexes form a unique geometrical structure.

  17. PACS on mobile devices

    NASA Astrophysics Data System (ADS)

    Parikh, Ashesh; Mehta, Nihal

    2015-03-01

    Recent advances in internet browser technologies makes it possible to incorporate advanced functionality of a traditional PACS for viewing DICOM medical images on standard web browsers without the need to pre-install any plug-ins, apps or software. We demonstrate some of the capabilities of standard web browsers setting the stage for a cloud-based PACS.

  18. Budgeting for PACS

    PubMed Central

    Sim, LH

    2008-01-01

    There are a number of models for the acquisition of digital image management systems. The specific details for development of a budget for a PACS/RIS acquisition will depend upon the acquisition model – although there are similarities in the overarching principles and general information, particularly concerning the radiology service requirements that will drive budget considerations. While budgeting for PACS/RIS should follow the same principles as budgeting for any new technology, it is important to understand how far the implementation of digital image management systems can reach in a healthcare setting. Accurate identification of those elements of the healthcare service that will be affected by a PACS/RIS implementation is a critical component of successful budget formation and of the success of any business case and subsequent project that relies on those budget estimates. A budget for a PACS/RIS capital acquisition project should contain capital and recurrent elements. The capital is associated with the acquisition of the system in a purchase model and capital budget may also be required for upgrade – depending upon a facility’s financial management processes. The recurrent (or operational) cost component for the PACS/RIS is associated with maintaining the system(s) in a sustainable operational state. It is also important to consider the service efficiencies, cost savings and service quality improvements that PACS/RIS can generate and include these factors into the economic analysis of any proposal for a PACS/RIS project. PMID:21611017

  19. Budgeting for PACS.

    PubMed

    Sim, Lh

    2008-10-01

    There are a number of models for the acquisition of digital image management systems. The specific details for development of a budget for a PACS/RIS acquisition will depend upon the acquisition model - although there are similarities in the overarching principles and general information, particularly concerning the radiology service requirements that will drive budget considerations.While budgeting for PACS/RIS should follow the same principles as budgeting for any new technology, it is important to understand how far the implementation of digital image management systems can reach in a healthcare setting. Accurate identification of those elements of the healthcare service that will be affected by a PACS/RIS implementation is a critical component of successful budget formation and of the success of any business case and subsequent project that relies on those budget estimates.A budget for a PACS/RIS capital acquisition project should contain capital and recurrent elements. The capital is associated with the acquisition of the system in a purchase model and capital budget may also be required for upgrade - depending upon a facility's financial management processes.The recurrent (or operational) cost component for the PACS/RIS is associated with maintaining the system(s) in a sustainable operational state.It is also important to consider the service efficiencies, cost savings and service quality improvements that PACS/RIS can generate and include these factors into the economic analysis of any proposal for a PACS/RIS project.

  20. Diffusivity of Cd in beta-Mn and beta-Mn(Al) measured by PAC

    NASA Astrophysics Data System (ADS)

    Zacate, Matthew O.; Collins, Gary S.

    2003-03-01

    Beta-Mn is a high-temperature allotrope stable between 720-1080 C with 20 atoms per unit cell on two inequivalent sites. Earlier perturbed angular correlation (PAC) measurements by M. Rots et al. showed that In/Cd impurities occupy the 12d site. It can be shown that jumps from one site to one of six neighboring 12d sites leads to reorientation of the electric-field gradient (efg) by angles close to 90^o. Jump frequencies of atoms were obtained by fitting the dynamically relaxed perturbation function using the method of Baudry and Boyer for N=3 orientations of the efg, with diffusivities proportional to jump frequencies. PAC measurements carried out on pure beta-Mn lead to D= 1.1(2) x 10-12 m^2/s at the lower phase boundary. Measurements were also made on alloys containing a few percent of aluminum, for which the diffusivity was found to be a factor of four lower. An Arrhenius plot for the alloy yielded an activation energy Q= 0.71(5) eV and prefactor D_0= 2(1) x 10-9 m^2/s. We are unaware of any previous measurement of diffusion in beta-Mn for comparison.

  1. Future of PACS

    NASA Astrophysics Data System (ADS)

    Kirchdoerfer, Richard G.

    1997-05-01

    This paper attempts to forecast tow to five years to understand the future PACS environment and is the result of reviews of literature and interviews with nearly thirty organization sand individuals representing the PACS community. Two to five years was set as a realistic limit to projections although thoughts for the future of digital medical imaging beyond five years are included. The variance in projections even in the short term is significant and any projection beyond five years will be even more uncertain. The organizations that contributed to the interviews include academic centers, the federal government, consultants and vendors of PACS technology. The vendor products span the industry to include capture of images at the modality level, image management and distribution systems, services, and speech recognition. This paper will place the changes that will occur in PACS within the context of the larger changes that are occurring in health care, the practice of image acquisition and interpretation, and information systems. Selected technologies that will influence PACS are reviewed in more depth with a view towards the affect that they will have on PACS and the interpretation of images.

  2. PACS image security server

    NASA Astrophysics Data System (ADS)

    Cao, Fei; Huang, H. K.

    2004-04-01

    Medical image security in a PACS environment has become a pressing issue as communications of images increasingly extends over open networks, and hospitals are currently hard-pushed by Health Insurance Portability and Accountability Act (HIPAA) to be HIPPA complaint for ensuring health data security. Other security-related guidelines and technical standards continue bringing to the public attention in healthcare. However, there is not an infrastructure or systematic method to implement and deploy these standards in a PACS. In this paper, we first review DICOM Part15 standard for secure communications of medical images and the HIPAA impacts on PACS security, as well as our previous works on image security. Then we outline a security infrastructure in a HIPAA mandated PACS environment using a dedicated PACS image security server. The server manages its own database of all image security information. It acts as an image Authority for checking and certificating the image origin and integrity upon request by a user, as a secure DICOM gateway to the outside connections and meanwhile also as a PACS operation monitor for HIPAA supporting information.

  3. The dynamics of oxygen vacancies in zirconia: An analysis of PAC data

    NASA Astrophysics Data System (ADS)

    Alves, Mauro A.

    Nuclear techniques such as perturbed angular correlation (PAC) sample the hyperfine interactions of a large number of probe atoms in specific crystallographic sites. Real crystals contain static defects producing a distribution of electric field gradients (EFGs) that add to the ideal EFG of the crystal at any given probe site. Also, dynamic defects like moving vacancies and interstitial atoms can be present in the crystal and contribute to the distribution of EFGs. The distribution of EFGs leads to line broadening and a change in the observed asymmetry parameter eta since the total EFG no longer has the symmetry of the perfect crystal. When both defects are present in a material, obtaining quantitative information from the analysis of PAC spectra is usually very difficult since great care has to be taken to ensure that the source of line broadening is identified correctly. In order to relate the relationship between the static line broadening and changes in the asymmetry parameter eta, a uniform random distribution of point charges was used to simulate the static defect EFG. PAC spectra collected on cubic niobium metal, cubic stabilized zirconia and Nb-doped tetragonal zirconia were fitted with this model. Although the quality of the fits is good, more work is needed to clarify the relationship between the new model parameters and the line broadening and asymmetry parameter derived from conventional model fits. The PAC spectra of Nb-doped tetragonal zirconia were fitted with a conventional static model to establish a reliable relationship between line broadening and the asymmetry parameter when only static defects are present in a sample. To account for effects of dynamic defects, a four state stochastic model for vacancy motion was adapted in order to include the line broadening and changes in the asymmetry produced by static defects. As a result, the activation energies corresponding to the rates at which a oxygen vacancy is trapped by, detraps from, and hops

  4. Dynamic hyperfine interactions in 111In(111Cd)-doped ZnO semiconductor: PAC results supported by ab initio calculations

    NASA Astrophysics Data System (ADS)

    Muñoz, Emiliano L.; Mercurio, Marcio E.; Cordeiro, Moacir R.; Pereira, Luciano F. D.; Carbonari, Artur W.; Rentería, Mario

    2012-08-01

    In this work, we present results of Time-Differential γ-γ Perturbed-Angular-Correlations (PAC) experiments performed in 111Cd-doped ZnO semiconductor. The PAC technique has been applied in order to characterize the electric-field-gradient (EFG) tensor at (111In (EC)→) 111Cd nuclei located, as was later demonstrated, at defect-free cation sites of the ZnO host structure. The PAC experiments were performed in the temperature range of 77-1075 K. At first glance, the unexpected presence of low-intensity dynamic hyperfine interactions was observed, which were analyzed with a perturbation factor based on the Bäverstam and Othaz model. The experimental EFG results were compared with ab initio calculations performed with the Full-Potential Augmented Plane Wave plus local orbital (FP-APW+lo) method, in the framework of the Density Functional Theory (DFT), using the Wien2K code. The presence of the dynamic hyperfine interactions has been analyzed enlightened by the FP-APW+lo calculations of the EFG performed as a function of the charge state of the cell. We could correlate the large strength of the dynamic hyperfine interaction with the strong variation of the EFG due to changes in the electronic charge distribution in the Cd vicinity during the time-window of the PAC measurement. It was also revealed that the Cd impurity decays to a final stable neutral charge state (Cd2+) fast enough (in few ns) to produce the nearly undamped observed PAC spectra.

  5. Educational RIS/PACS simulator

    NASA Astrophysics Data System (ADS)

    Zhou, Zheng; Law, Maria Y. Y.; Huang, H. K.; Cao, Fei; Liu, Brent J.; Zhang, Jianguo; Mogel, Greg T.; Zhuang, Jun

    2003-05-01

    Many educational courses have been designed for training radiologists and allied healthcare providers to operate PACS workstations. There are yet tools available for educational training of PACS concepts and workflow analysis. We have designed and implemented a RIS/PACS Simulator for this purpose. The RIS/PACS Simulator consists of six key components simulating a typical clinical RIS/PACS: RIS simulator, acquisition modality Simulator (AMS), DICOM gateway, PACS controller (UNIX-based), clinical viewing workstation, and network infrastructure with a 100mbits/sec Ethernet switch connecting to all these components. A generic RIS and a generic DICOM compliant PACS software package are used to simulate normal clinical data flow. Using this simulator, trainees can: 1. Observe clinical RIS/PACS operation, component by component 2. Trace image flow through each component 3. Identify PACS data flow bottle neck 4. Induce failure in a component to observe its impact on the PACS workflow and operation RIS/PACS simulator is a valuable tool for participants to gain knowledge of the complexity of RIS/PACS data flow with hands-on experience. As a stand-alone system, it also becomes a good test bed for evaluation of medical imaging applications without interrupting clinical workflow.

  6. Factors Affecting Radiologist's PACS Usage.

    PubMed

    Forsberg, Daniel; Rosipko, Beverly; Sunshine, Jeffrey L

    2016-12-01

    The purpose of this study was to determine if any of the factors radiologist, examination category, time of week, and week effect PACS usage, with PACS usage defined as the sequential order of computer commands issued by a radiologist in a PACS during interpretation and dictation. We initially hypothesized that only radiologist and examination category would have significant effects on PACS usage. Command logs covering 8 weeks of PACS usage were analyzed. For each command trace (describing performed activities of an attending radiologist interpreting a single examination), the PACS usage variables number of commands, number of command classes, bigram repetitiveness, and time to read were extracted. Generalized linear models were used to determine the significance of the factors on the PACS usage variables. The statistical results confirmed the initial hypothesis that radiologist and examination category affect PACS usage and that the factors week and time of week to a large extent have no significant effect. As such, this work provides direction for continued efforts to analyze system data to better understand PACS utilization, which in turn can provide input to enable optimal utilization and configuration of corresponding systems. These continued efforts were, in this work, exemplified by a more detailed analysis using PACS usage profiles, which revealed insights directly applicable to improve PACS utilization through modified system configuration.

  7. Measurement of Aerosol and Cloud Particles with PACS and HARP Hyperangular Imaging Polarimeters

    NASA Astrophysics Data System (ADS)

    Martins, J.; Fernandez-Borda, R.; Remer, L. A.; Sparr, L.; Buczkowski, S.; Munchak, L. A.

    2013-12-01

    PACS is new hyper-angular imaging polarimeter for aeorosol and cloud measurerents designed to meet the requirements of the proposed ACE decadal survey mission. The full PACS system consists of three wide field of view (110deg cross track) telescopes covering the UV, VNIR, and SWIR spectral ranges with angular coverage between +55 deg forward to -55deg backwards. The angular density can be selected to cover up to 100 different viewing angles at selected wavelengths. PACS_VNIR is a prototype airborne instrument designed to demonstrate PACS capability by deploying just one of the three wavelength modules of the full PACS. With wavelengths at 470, 550, 675, 760 and 875nm, PACS_VNIR flew for the first time during the PODEX experiment in January/February 2013 aboard the NASA ER-2 aircraft. PACS SWIR (1.64, 1.88, 2.1, and 2.25um) is currently under construction and should be operational in the lab by Fall/2013. PACS_ UV has been fully designed, but is not yet under construction. During the PODEX flights PACS_VNIR collected data for aerosol and clouds over variable surface types including, water, vegetation, urban areas, and snow. The data is currently being calibrated, geolocated and prepared for the inversion of geophysical parameters including water cloud size distribution and aerosol microphysical parameters. The large density of angles in PACS allows for the characterization of cloudbow features in relatively high spatial resolution in a pixel to pixel basis. This avoids the need for assumptions of cloud homogeneity over any distance. The hyperangle capability also allows detailed observation of cloud ice particles, surface characterization, and optimum selection of the number of angles desired for aerosol retrievals. The aerosol and cloud retrieval algorithms under development for the retrieval of particle microphysical properties from the PACS data will be discussed in this presentation. As an extension of the PACS concept we are currently developing the HARP (Hyper-Angular

  8. Investigation of hyperfine interactions in GdCrO3 perovskite oxide using PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Silva, Renilson A. Da; Saxena, R. N.; Carbonari, A. W.; Cabrera-Pasca, G. A.

    2010-04-01

    Perturbed angular correlation (PAC) measurements have been carried out in the antiferromagnetic GdCrO3 perovskite oxide using 111In (111Cd) and 181Hf(181Ta) nuclear probes. The radioactive parent nuclei 111In and 181Hf were introduced in the compound through a chemical process during sample preparation. The PAC measurements were carried out in the temperature range 20-300 K. Measurements with the 181Ta indicated a unique quadrupole interaction above 170 K and a combined electric quadrupole and magnetic dipole interactions below this temperature. The observed interaction was assigned to the probe nuclei substituting Cr sites. Measurements with 111Cd showed two quadrupole interactions. Only one of the fractions however, showed a combined electric and magnetic interaction in the temperature rage 20-170 K which was assigned to 111Cd probe substituting Cr site. The other fraction was attributed to the Gd site. The present results are compared with those of LaCrO3 and NdCrO3.

  9. PACS and image storage.

    PubMed

    Armbrust, Laura J

    2009-07-01

    Storage and retrieval of digital images is an integral component of any digital imaging system. A picture archiving and communication system (PACS) includes hardware and software that allows for display, storage, retrieval, and communication functions. PACS software allows for manipulation of the images to enhance interpretation by way of changes in contrast, brightness, magnification, and measurements, among others. Digital images for medical imaging should be in the digital imaging communications in medicine file format. This specified format allows for interconnectivity between imaging systems from different vendors and is important to ensure appropriate security. A hospital information system or radiology information system can be used to tie the patient record with the digital images in a paperless medical record system.

  10. Clinical determinants of PACS acceptance

    NASA Astrophysics Data System (ADS)

    Saarinen, Allan O.; Youngs, Gayle L.; Haynor, David R.; Loop, John W.

    1990-08-01

    One of the key determinants influencing how successfully a radiology department can convert from a conventional film-based environment to an exclusively digital imaging environment may be how well referring physician members of the hospital staff who are not radiologists endorse this new system. The benefits of Picture Archive and Communication Systems (PACS) to radiologists are becoming widely accepted and documented; however, physicians who interact with the radiology department represent an important user group whose views on PACS are less well understood. The acceptance of PACS by referring physicians (clinicians) may be critical to the overall utility ofPACS as well as a major drivingforce behind why a hospitalpurchases PACS. The degree to which referring physicians support PACS may be dependent upon many factors. This study identifies several aspects through the administration and analysis ofa survey which improve PACS acceptance by nonradiology physicians. It appears the more patients a referring physician sends to the radiology department, the more time a physician spends traveling to andfrom thefllmflle room retrievingfllms, and, the more interested a referring physician is about computers, the higher his interest is in PACS. If a referring physician believes that PACS will save him or her time, will reduce the incidence oflostfilms, or will cause performance of radiology exams or generation of reports to be more efficient, the referring physician appears more likely to support PACS and to make the initial time investment necessary to learn how PACS equipment operates. The factors which cause referring physicians to support PACS are principally: (1) the elimination oflost, misplaced, and checked outfllms, and (2) the elimination oftrips to and from thefile room. The major distractions ofthe technology are: (1) system reliability, and (2) reduced diagnostic capability. While the high cost ofPACS is also a distraction, it is not the predominant concern.

  11. Induced Angular Momentum

    ERIC Educational Resources Information Center

    Parker, G. W.

    1978-01-01

    Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)

  12. Induced Angular Momentum

    ERIC Educational Resources Information Center

    Parker, G. W.

    1978-01-01

    Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)

  13. LOCAL MAGNETIC BEHAVIOR OF 54Fe in EuFe2As2 AND Eu0.5K0.5Fe2As2: MICROSCOPIC STUDY USING TIME DIFFERENTIAL PERTURBED ANGULAR DISTRIBUTION (TDPAD) SPECTROSCOPY

    NASA Astrophysics Data System (ADS)

    Mohanta, S. K.; Mishra, S. N.; Davane, S. M.; Layek, S.; Hossain, Z.

    2013-12-01

    In this paper, we report the time differential perturbed angular distribution measurements of 54Fe on a polycrystalline EuFe2As2 and Eu0.5K0.5Fe2As2. The hyperfine field and nuclear spin-relaxation rate are strongly temperature dependent in the paramagnetic state suggesting strong spin fluctuation in the parent compound. The local susceptibility show Curie-Weiss-like temperature dependence and Korringa-like relaxation in the tetragonal phase indicating the presence of local moment. In the orthorhombic phase, the hyperfine field behavior suggesting quasi two-dimensional magnetic ordering. The experimental results are in a good agreement with first-principle calculations based on density functional theory.

  14. Fault-tolerant PACS server

    NASA Astrophysics Data System (ADS)

    Cao, Fei; Liu, Brent J.; Huang, H. K.; Zhou, Michael Z.; Zhang, Jianguo; Zhang, X. C.; Mogel, Greg T.

    2002-05-01

    Failure of a PACS archive server could cripple an entire PACS operation. Last year we demonstrated that it was possible to design a fault-tolerant (FT) server with 99.999% uptime. The FT design was based on a triple modular redundancy with a simple majority vote to automatically detect and mask a faulty module. The purpose of this presentation is to report on its continuous developments in integrating with external mass storage devices, and to delineate laboratory failover experiments. An FT PACS Simulator with generic PACS software has been used in the experiment. To simulate a PACS clinical operation, image examinations are transmitted continuously from the modality simulator to the DICOM gateway and then to the FT PACS server and workstations. The hardware failures in network, FT server module, disk, RAID, and DLT are manually induced to observe the failover recovery of the FT PACS to resume its normal data flow. We then test and evaluate the FT PACS server in its reliability, functionality, and performance.

  15. Vendor neutral archive in PACS.

    PubMed

    Agarwal, Tapesh Kumar; Sanjeev

    2012-10-01

    An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. "Vendor neutral" may not be a suitable term, and "architecture neutral," "PACS neutral," "content neutral," or "third-party neutral" are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe.

  16. PACS: moving a live PACS with zero downtime

    NASA Astrophysics Data System (ADS)

    Romlein, John R.; Lyche, David K.; Chacko, Anna K.; Cawthon, Michael A.; Vanderburgh, David; Stokes, Ron

    2000-05-01

    As PACS implementations increase during the new millennium, the need to plan and execute the movement of a live PACS from an existing facility into a replacement hospital increases. Such an undertaking should support not only the physical movement of the existing PACS but also the continuous support of clinical radiology operations throughout the transition period. This paper will describe two successful transitions of live PACS into newly constructed replacement hospitals. In 1994 the Brooke Army Medical Center transitioned into a newly constructed 450-bed facility in San Antonio Texas. In 1999 a similar movement of the Elmendorf Air Force Medical Center was successful accomplished in Anchorage Alaska. Both moves provided continuous operations of the Radiology Department and full clinical services in the old facilities in a near filmless mode while fully supporting the simultaneous installation and testing of new PACS components and PACS-to- modality interfaces in the new facilities. The process also included the migration of the image archives and acceptance testing of the final installation. While the exact migration process must differ, depending on the PACS architecture and the facility transition plans, these two examples provide a general framework for the issues and strategies for such a move.

  17. Angular Scaling In Jets

    SciTech Connect

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC

    2012-02-17

    We introduce a jet shape observable defined for an ensemble of jets in terms of two-particle angular correlations and a resolution parameter R. This quantity is infrared and collinear safe and can be interpreted as a scaling exponent for the angular distribution of mass inside the jet. For small R it is close to the value 2 as a consequence of the approximately scale invariant QCD dynamics. For large R it is sensitive to non-perturbative effects. We describe the use of this correlation function for tests of QCD, for studying underlying event and pile-up effects, and for tuning Monte Carlo event generators.

  18. 'PACS at Penn'

    NASA Astrophysics Data System (ADS)

    Arenson, Ronald L.; Seshadri, Sridhar B.; Kundel, Harold L.; DeSimone, Debra

    1989-05-01

    History: Our experience with Medical Image Management Systems (MIMS, also called PACS) began in 1982 with the creation of a digital subtraction angiography (DSA) unit. This DSA system was built utilizing a DeAnza image array processor with boards fabricated by our staff to interface with a Siemens angiography room. Because of the need to transmit and eventually store very large image files on a remote computer, we designed and fabricated a point-to-point fiber-optic link [82-ARENA. This device was later marketed by Canoga Systems and was an important contribution to the design of commercial fiber-optic networks. Recognizing the importance of a versatile Radiology Information System (RIS) and its critical inter-relationship to a MIMS, some very early work on RIS design was carried out [79-ARENA, [79.B-AREN ], [84-AREN ].

  19. History of PACS in Asia.

    PubMed

    Inamura, Kiyonari; Kim, Jong Hyo

    2011-05-01

    First, history of PACS (picture archiving and communication system for medical use) in Japan is described in two parts: in part 1, the early stage of PACS development from 1984 to 2002, and in part 2 the matured stage from 2002 to 2010. PACS in Japan has been developed and installed by local manufacturers by their own technology and demand from domestic hospitals. Part 1 mainly focuses on quantitative growth and part 2 on qualitative change. In part 2, integration of PACS into RIS (radiology information system), HIS (hospital information system), EPR (electronic patient record), teleradiology and IHE (integrating healthcare enterprise) is reported. Interaction with other elements of technology such as moving picture network system and three dimensional display is also discussed. Present situation of main 4 large size hospitals is presented. Second, history of PACS in Korea is reported. Very acute climbing up of filmless PACS diffusion was observed from 1997 to 2000. The reasons for such evolution are described and discussed. Also changes of PACS installation and system integration with other systems such as HIS and role of them in radiological diagnoses in Korea since 2002 are described. Third, history in China is investigated by checking international academic journals in English and described as far as events are logically linked and consistently meaningful.

  20. Vendor neutral archive in PACS

    PubMed Central

    Agarwal, Tapesh Kumar; Sanjeev

    2012-01-01

    An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. “Vendor neutral” may not be a suitable term, and “architecture neutral,” “PACS neutral,” “content neutral,” or “third-party neutral” are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe. PMID:23833411

  1. Enterprise PACS and image distribution.

    PubMed

    Huang, H K

    2003-01-01

    Around the world now, because of the need to improve operation efficiency and better cost effective healthcare, many large-scale healthcare enterprises have been formed. Each of these enterprises groups hospitals, medical centers, and clinics together as one enterprise healthcare network. The management of these enterprises recognizes the importance of using PACS and image distribution as a key technology in cost-effective healthcare delivery in the enterprise level. As a result, many large-scale enterprise level PACS/image distribution pilot studies, full design and implementation, are underway. The purpose of this paper is to provide readers an overall view of the current status of enterprise PACS and image distribution. reviews three large-scale enterprise PACS/image distribution systems in USA, Germany, and South Korean. The concept of enterprise level PACS/image distribution, its characteristics and ingredients are then discussed. Business models for enterprise level implementation available by the private medical imaging and system integration industry are highlighted. One current system under development in designing a healthcare enterprise level chest tuberculosis (TB) screening in Hong Kong is described in detail.

  2. PACS photometer calibration block analysis

    NASA Astrophysics Data System (ADS)

    Moór, A.; Müller, T. G.; Kiss, C.; Balog, Z.; Billot, N.; Marton, G.

    2014-07-01

    The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5 % (standard deviation) or about 8 % peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements by a fixed and time-independent response file, without using any information from the PACS internal calibration sources. However, the analysis of calibration block observations revealed clear correlations of the internal source signals with the evaporator temperature and a signal drift during the first half hour after the cooler recycling. These effects are small, but can be seen in repeated measurements of standard stars. From our analysis we established corrections for both effects which push the stability of the PACS bolometer response to about 0.2 % (stdev) or 2 % in the blue, 3 % in the green and 5 % in the red channel (peak-to-peak). After both corrections we still see a correlation of the signals with PACS FPU temperatures, possibly caused by parasitic heat influences via the Kevlar wires which connect the bolometers with the PACS Focal Plane Unit. No aging effect or degradation of the photometric system during the mission lifetime has been found.

  3. Writing a PACS program statement.

    PubMed

    Rowe, W M; Moffitt, M E; Bunnell, W J

    1995-01-01

    Medical telecommunications is becoming a necessity for maintaining the quality of care and delivering services on a timely basis in the current environment of cutting services and specialists to reduce costs. (Vanden Brink 1994). Picture archiving and communications systems (PACS) and teleradiology are increasingly viable because there is easier connectivity among modalities and manufacturers. Agreement on the DICOM Standard is one step toward greater connectivity. Two-thirds of the 350 radiology administrators, radiologists, hospital administrators and MIS directors interviewed for the 1994 IMACS/PACS Tracking Study believe that the use of image telecommunication technology is growing. In 1993, Vanderbilt University Medical Center (VUMC) formed a committee to evaluate the need for PACS and to compile a program statement. The principal purpose of the program statement is to provide fundamental information that can be understood easily by individuals outside the radiology department. It outlines the benefits of PACS and includes a financial analysis of the purchase and installation of a system. Key elements of the program statement include a description and analysis of the existing film library system, advantages of PACS, implementation plan, financial proforma and integration with the hospital information system. These and other topics are covered in detail in the following article.

  4. PCaPAC 2006 Proceedings

    SciTech Connect

    Pavel Chevtsov; Matthew Bickley

    2007-03-30

    The 6-th international PCaPAC (Personal Computers and Particle Accelerator Controls) workshop was held at Jefferson Lab, Newport News, Virginia, from October 24-27, 2006. The main objectives of the conference were to discuss the most important issues of the use of PCs and modern IT technologies for controls of accelerators and to give scientists, engineers, and technicians a forum to exchange the ideas on control problems and their solutions. The workshop consisted of plenary sessions and poster sessions. No parallel sessions were held.Totally, more than seventy oral and poster presentations as well as tutorials were made during the conference, on the basis of which about fifty papers were submitted by the authors and included in this publication. This printed version of the PCaPAC 2006 Proceedings is published at Jefferson Lab according to the decision of the PCaPAC International Program Committee of October 26, 2006.

  5. Preparation of PAC libraries. Final technical report

    SciTech Connect

    Pieter J. de Jong

    1997-12-31

    The goals of this project were to create P1 Artificial Chromosome (PAC) cloning vectors and use these vectors to generate, characterize, and distribute both human and mouse genomic PAC libraries to the scientific community.

  6. 24 CFR 891.725 - PAC administration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false PAC administration. 891.725 Section... Individuals-Section 162 Assistance § 891.725 PAC administration. HUD is responsible for the administration of the PAC....

  7. 24 CFR 891.725 - PAC administration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false PAC administration. 891.725 Section... Individuals-Section 162 Assistance § 891.725 PAC administration. HUD is responsible for the administration of the PAC....

  8. 24 CFR 891.725 - PAC administration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false PAC administration. 891.725 Section... Individuals-Section 162 Assistance § 891.725 PAC administration. HUD is responsible for the administration of the PAC....

  9. 24 CFR 891.725 - PAC administration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false PAC administration. 891.725 Section... Individuals-Section 162 Assistance § 891.725 PAC administration. HUD is responsible for the administration of the PAC....

  10. 24 CFR 891.725 - PAC administration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false PAC administration. 891.725 Section... Individuals-Section 162 Assistance § 891.725 PAC administration. HUD is responsible for the administration of the PAC....

  11. PACS and electronic health records

    NASA Astrophysics Data System (ADS)

    Cohen, Simona; Gilboa, Flora; Shani, Uri

    2002-05-01

    Electronic Health Record (EHR) is a major component of the health informatics domain. An important part of the EHR is the medical images obtained over a patient's lifetime and stored in diverse PACS. The vision presented in this paper is that future medical information systems will convert data from various medical sources -- including diverse modalities, PACS, HIS, CIS, RIS, and proprietary systems -- to HL7 standard XML documents. Then, the various documents are indexed and compiled to EHRs, upon which complex queries can be posed. We describe the conversion of data retrieved from PACS systems through DICOM to HL7 standard XML documents. This enables the EHR system to answer queries such as 'Get all chest images of patients at the age of 20-30, that have blood type 'A' and are allergic to pine trees', which a single PACS cannot answer. The integration of data from multiple sources makes our approach capable of delivering such answers. It enables the correlation of medical, demographic, clinical, and even genetic information. In addition, by fully indexing all the tagged data in DICOM objects, it becomes possible to offer access to huge amounts of valuable data, which can be better exploited in the specific radiology domain.

  12. Large-scale PACS implementation.

    PubMed

    Carrino, J A; Unkel, P J; Miller, I D; Bowser, C L; Freckleton, M W; Johnson, T G

    1998-08-01

    The transition to filmless radiology is a much more formidable task than making the request for proposal to purchase a (Picture Archiving and Communications System) PACS. The Department of Defense and the Veterans Administration have been pioneers in the transformation of medical diagnostic imaging to the electronic environment. Many civilian sites are expected to implement large-scale PACS in the next five to ten years. This presentation will related the empirical insights gleaned at our institution from a large-scale PACS implementation. Our PACS integration was introduced into a fully operational department (not a new hospital) in which work flow had to continue with minimal impact. Impediments to user acceptance will be addressed. The critical components of this enormous task will be discussed. The topics covered during this session will include issues such as phased implementation, DICOM (digital imaging and communications in medicine) standard-based interaction of devices, hospital information system (HIS)/radiology information system (RIS) interface, user approval, networking, workstation deployment and backup procedures. The presentation will make specific suggestions regarding the implementation team, operating instructions, quality control (QC), training and education. The concept of identifying key functional areas is relevant to transitioning the facility to be entirely on line. Special attention must be paid to specific functional areas such as the operating rooms and trauma rooms where the clinical requirements may not match the PACS capabilities. The printing of films may be necessary for certain circumstances. The integration of teleradiology and remote clinics into a PACS is a salient topic with respect to the overall role of the radiologists providing rapid consultation. A Web-based server allows a clinician to review images and reports on a desk-top (personal) computer and thus reduce the number of dedicated PACS review workstations. This session

  13. Angular Momentum

    ERIC Educational Resources Information Center

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

    The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

  14. Angular Momentum

    ERIC Educational Resources Information Center

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

    The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

  15. PACS strategy for imaging centers.

    PubMed

    Bedel, Victoria; Zdanowicz, Mark

    2004-01-01

    Picture archiving and communications systems (PACS) have been available in imaging centers for many years, but they often were less functional, were not well integrated into patient information systems, and lacked the network backbone to implement a system. As modalities are replaced and technology improves, the ability and time for an imaging center to acquire, integrate, and utilize PACS has arrived. However, each imaging center must determine why it should invest in PACS. A business plan is the fundamental need. Each imaging center must understand its target market, growth rate, and staffing plans. Additional considerations lie in current and future modality availability, the need for offsite delivery of images and reports, and the potential need for remote transmission of images. These issues must be identified and prioritized. A multidisciplinary team is essential. The most successful PACS implementation begins with complete involvement from all levels. The team should be comprised of people with complementary skills who are committed to a common purpose, set of performance goals, and approach for which they hold themselves mutually accountable. The team must jointly decide on the project's objectives. These objectives fall under 4 categories: clinical, service, financial, and performance. PACS must be considered a tool to help accomplish each objective. The imaging center must determine its top priorities, then translate them into a technology "wish list." The center can then list those pieces of technology that are most important and prioritize them. There are even more considerations for connecting multiple imaging centers. The team must create a comprehensive request for proposal (RFP) and determine the vendors that will receive the document. Once the RFP responses have been received and the vendor has been selected, an effective training plan must be executed. Training plans should be competency-based, ensuring comfort and competency among all staff. Upon

  16. Ten Years Of PACS Experience

    NASA Astrophysics Data System (ADS)

    Hindel, Robert; Meyer-Ebrecht, Dieter; Heu, Ruettger; Oosterwijk, Herman

    1989-05-01

    A few of us here can look back ten years or more of having observed or even having participated in the PACS development. Depending on our point of view, little or much progress has been made since 1978. In the following, the authors will sketch a log book of an industrial developer and vendor, i.e., Philips Medical Systems. Some comments will turn out to be specifically applicable to the Philips Concern but the majority is probably also true for other major X-ray manufacturing companies. There are certain ground rules which have to be observed if a company wants to prove itself in a market as ambitious and complex as the medical market and, in particular, the PACS market. These ground rules will be either explicitly mentioned or are implied for the attentive listener. The following aspects will be considered:

  17. Integrating image processing in PACS.

    PubMed

    Faggioni, Lorenzo; Neri, Emanuele; Cerri, Francesca; Turini, Francesca; Bartolozzi, Carlo

    2011-05-01

    Integration of RIS and PACS services into a single solution has become a widespread reality in daily radiological practice, allowing substantial acceleration of workflow with greater ease of work compared with older generation film-based radiological activity. In particular, the fast and spectacular recent evolution of digital radiology (with special reference to cross-sectional imaging modalities, such as CT and MRI) has been paralleled by the development of integrated RIS--PACS systems with advanced image processing tools (either two- and/or three-dimensional) that were an exclusive task of costly dedicated workstations until a few years ago. This new scenario is likely to further improve productivity in the radiology department with reduction of the time needed for image interpretation and reporting, as well as to cut costs for the purchase of dedicated standalone image processing workstations. In this paper, a general description of typical integrated RIS--PACS architecture with image processing capabilities will be provided, and the main available image processing tools will be illustrated.

  18. Renormalized Lie perturbation theory

    SciTech Connect

    Rosengaus, E.; Dewar, R.L.

    1981-07-01

    A Lie operator method for constructing action-angle transformations continuously connected to the identity is developed for area preserving mappings. By a simple change of variable from action to angular frequency a perturbation expansion is obtained in which the small denominators have been renormalized. The method is shown to lead to the same series as the Lagrangian perturbation method of Greene and Percival, which converges on KAM surfaces. The method is not superconvergent, but yields simple recursion relations which allow automatic algebraic manipulation techniques to be used to develop the series to high order. It is argued that the operator method can be justified by analytically continuing from the complex angular frequency plane onto the real line. The resulting picture is one where preserved primary KAM surfaces are continuously connected to one another.

  19. Sphere-Pac Evaluation for Transmutation

    SciTech Connect

    Icenhour, A.S.

    2005-05-19

    The U.S. Department of Energy Advanced Fuel Cycle Initiative (AFCI) is sponsoring a project at Oak Ridge National Laboratory with the objective of conducting the research and development necessary to evaluate the use of sphere-pac transmutation fuel. Sphere-pac fuels were studied extensively in the 1960s and 1970s. More recently, this fuel form is being studied internationally as a potential plutonium-burning fuel. For transmutation fuel, sphere-pac fuels have potential advantages over traditional pellet-type fuels. This report provides a review of development efforts related to the preparation of sphere-pac fuels and their irradiation tests. Based on the results of these tests, comparisons with pellet-type fuels are summarized, the advantages and disadvantages of using sphere-pac fuels are highlighted, and sphere-pac options for the AFCI are recommended. The Oak Ridge National Laboratory development activities are also outlined.

  20. PACS meets digital library: issues and applications

    NASA Astrophysics Data System (ADS)

    Wong, Stephen T. C.; Hoo, Kent S., Jr.; Whaley, Pablo S.; Velez, Olivia; English, Camper D.; Huang, H. K.

    1997-05-01

    The purpose of this presentation is to point out the issues of incorporating digital libraries (DL) technologies into picture archiving and communication systems (PACS). The DL technologies can be used to increase the knowledge content and utilities of PACS and associated medical information systems in providing a broader range of medical services. We further illustrate certain potential application areas with examples from a research prototype developed on top of the hospital-integrated PACS of UCSF.

  1. Phonons with orbital angular momentum

    SciTech Connect

    Ayub, M. K.; Ali, S.; Mendonca, J. T.

    2011-10-15

    Ion accoustic waves or phonon modes are studied with orbital angular momentum (OAM) in an unmagnetized collissionless uniform plasma, whose constituents are the Boltzmann electrons and inertial ions. For this purpose, we have employed the fluid equations to obtain a paraxial equation in terms of ion density perturbations and discussed its Gaussian beam and Laguerre-Gauss (LG) beam solutions. Furthermore, an approximate solution for the electrostatic potential problem is presented, allowing to express the components of the electric field in terms of LG potential perturbations. The energy flux due to phonons is also calculated and the corresponding OAM is derived. Numerically, it is shown that the parameters such as azimuthal angle, radial and angular mode numbers, and beam waist, strongly modify the profiles of the phonon LG potential. The present results should be helpful in understanding the phonon mode excitations produced by Brillouin backscattering of laser beams in a uniform plasma.

  2. HIS-PACS Coupling In Practice

    NASA Astrophysics Data System (ADS)

    Lodder, Herman; van Poppel, Bas M.; J. de Valk, Jan P.; Wilmink, Hans B. M.; Ising, Carola; Bakker, Ab R.

    1989-05-01

    The existence of a link between a HIS, incorporating a RIS, and a PACS is one of the most indispensible prerequisites to perform a clinical evaluation study of a PACS in practice. The two main reasons for realizing a IIIS-PACS coupling are concerned with 1) proper image management e.g. in order to achieve acceptable waiting times and 2) the user need of having all patient relevant data available in the same workstation. A first phase coupling between an existing HIS and a just installed PACS has been realized by BAZIS in the Utrecht University Hospital in the Netherlands. These activities were carried out as part of the Dutch PACS Project, a collaboration in the PACS field of BAZIS, the Utrecht University Hospital (AZU) and Philips Medical Systems. For the first phase only HIS data of the in-patients of one particular ward of Internal Medicine were transmitted using a one-way dataflow (from. HIS to PACS). In phase two the coupling will he hi-directional and more departments will be part of the experiment. In phase three of the coupling project a more general. HIS-PACS interface will be developed, independent of the HIS and PACS manufacturers. In April 1988 the first public data exchange (patient data, order data, reports) between the BAZIS/ZIS and Philips/MARCOM system has been demonstrated. This was the first working example of a HIS-PACS coupling worldwide to our knowledge. This paper gives an overview of the experimental set-up, the demonstration during the 6th EuroPACS meeting , the results and problems encountered thusfar and statistical data from daily practice.

  3. Archival storage solutions for PACS

    NASA Astrophysics Data System (ADS)

    Chunn, Timothy

    1997-05-01

    While they are many, one of the inhibitors to the wide spread diffusion of PACS systems has been robust, cost effective digital archive storage solutions. Moreover, an automated Nearline solution is key to a central, sharable data repository, enabling many applications such as PACS, telemedicine and teleradiology, and information warehousing and data mining for research such as patient outcome analysis. Selecting the right solution depends on a number of factors: capacity requirements, write and retrieval performance requirements, scaleability in capacity and performance, configuration architecture and flexibility, subsystem availability and reliability, security requirements, system cost, achievable benefits and cost savings, investment protection, strategic fit and more.This paper addresses many of these issues. It compares and positions optical disk and magnetic tape technologies, which are the predominant archive mediums today. Price and performance comparisons will be made at different archive capacities, plus the effect of file size on storage system throughput will be analyzed. The concept of automated migration of images from high performance, high cost storage devices to high capacity, low cost storage devices will be introduced as a viable way to minimize overall storage costs for an archive. The concept of access density will also be introduced and applied to the selection of the most cost effective archive solution.

  4. CHILD-PACs Make for Happy Families.

    ERIC Educational Resources Information Center

    Patton, Mary Martin; Jones, Elizabeth

    1997-01-01

    Describes CHILD-PAC (Children's Hand-on Integrated Learning Discoveries--Parents as Co-Partners), a take-home learning center developed for infants and toddlers with disabilities and their parents to promote positive, interactive parent-child learning and playing. Three different CHILD-PACs designed to turn potentially difficult interaction times…

  5. Web-based PACS and EHR system

    NASA Astrophysics Data System (ADS)

    Parikh, Ashesh; Mehta, Nihal

    2015-03-01

    We demonstrate how a cloud-based PACS can exchange information with other medical systems, including other cloud-based PACS, to provide a comprehensive and integrated view of a patient's health record. Such a consolidated report will lead to improved patient care.

  6. Investigation of hyperfine interactions in RMO3 (R =La, Nd; M =Cr, Fe) antiferromagnetic perovskite oxides using PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Carbonari, A. W.; Cavalcante, F. H. M.; Junqueira, A. C.; Leite, D. M. T.; Saxena, R. N.; Mestnik-Filho, J.

    The local magnetic interaction at the transition metal sites in RMO3 (R=La, Nd; M=Cr, Fe) compounds has been investigated by perturbed angular correlation (PAC) technique using 181Hf→181Ta probe nuclei. The present measurements cover a temperature range from 10 K to 1000 K. Above the respective Neel temperature, each compound shows a unique quadrupolar frequency that decreases linearly with temperature. These interactions were assigned to the radioactive probe substituting Cr or Fe sites. Below TN, a combined electric plus magnetic hyperfine interaction was observed. The magnetic interaction revealed that the super transferred hyperfine fields on 181Ta at the Cr sites in (La,Nd)CrO3 extrapolated to 0 K, are much smaller than the corresponding values at Fe sites in (La,Nd)FeO3. This difference was attributed to different distribution of d electrons in Cr3+ (3d3) and Fe3+ (3d5) ions in each compound. As the fields for Nd compounds are smaller than those for La compounds, the role of rare-earth ions in the magnetism of these oxides is also discussed.

  7. Investigation of hyperfine interactions in RMO 3 (R = La, Nd; M = Cr, Fe) antiferromagnetic perovskite oxides using PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Carbonari, A. W.; Cavalcante, F. H. M.; Junqueira, A. C.; Leite, D. M. T.; Saxena, R. N.; Mestnik-Filho, J.

    2007-07-01

    The local magnetic interaction at the transition metal sites in RMO3 (R = La, Nd; M = Cr, Fe) compounds has been investigated by perturbed angular correlation (PAC) technique using 181Hf→181Ta probe nuclei. The present measurements cover a temperature range from 10 K to 1000 K. Above the respective Néel temperature, each compound shows a unique quadrupolar frequency that decreases linearly with temperature. These interactions were assigned to the radioactive probe substituting Cr or Fe sites. Below T N , a combined electric plus magnetic hyperfine interaction was observed. The magnetic interaction revealed that the super transferred hyperfine fields on 181Ta at the Cr sites in (La,Nd)CrO3 extrapolated to 0 K, are much smaller than the corresponding values at Fe sites in (La,Nd)FeO3. This difference was attributed to different distribution of d electrons in Cr3 + (3d3) and Fe3 + (3d5) ions in each compound. As the fields for Nd compounds are smaller than those for La compounds, the role of rare-earth ions in the magnetism of these oxides is also discussed.

  8. Towards a theory of PACS deployment: an integrative PACS maturity framework.

    PubMed

    van de Wetering, Rogier; Batenburg, Ronald

    2014-06-01

    Owing to large financial investments that go along with the picture archiving and communication system (PACS) deployments and inconsistent PACS performance evaluations, there is a pressing need for a better understanding of the implications of PACS deployment in hospitals. We claim that there is a gap in the research field, both theoretically and empirically, to explain the success of the PACS deployment and maturity in hospitals. Theoretical principles are relevant to the PACS performance; maturity and alignment are reviewed from a system and complexity perspective. A conceptual model to explain the PACS performance and a set of testable hypotheses are then developed. Then, structural equation modeling (SEM), i.e. causal modeling, is applied to validate the model and hypotheses based on a research sample of 64 hospitals that use PACS, i.e. 70 % of all hospitals in the Netherlands. Outcomes of the SEM analyses substantiate that the measurements of all constructs are reliable and valid. The PACS alignment-modeled as a higher-order construct of five complementary organizational dimensions and maturity levels-has a significant positive impact on the PACS performance. This result is robust and stable for various sub-samples and segments. This paper presents a conceptual model that explains how alignment in deploying PACS in hospitals is positively related to the perceived performance of PACS. The conceptual model is extended with tools as checklists to systematically identify the improvement areas for hospitals in the PACS domain. The holistic approach towards PACS alignment and maturity provides a framework for clinical practice.

  9. Picture archiving and communication systems (PACS).

    PubMed

    Gamsu, Gordon; Perez, Enrico

    2003-07-01

    Over the past 2 decades, groups of computer scientists, electronic design engineers, and physicians, in universities and industry, have worked to achieve an electronic environment for the practice of medicine and radiology. The radiology component of this revolution is often called PACS (picture archiving and communication systems). More recently it has become evident that the efficiencies and cost savings of PACS are realized when they are part of an enterprise-wide electronic medical record. The installation of PACS requires careful planning by all the various stakeholds over many months prior to installation. All of the users must be aware of the initial disruption that will occur as they become familiar with the systems. Modern fourth generation PACS is linked to radiology and hospital information systems. The PACS consist of electronic acquisition sites-a robust network intelligently managed by a server, multiple viewing sites, and an archive. The details of how these are linked and their workflow analysis determines the success of PACS. PACS evolves over time, components are frequently replaced, and so the users must expect continuous learning about new updates and improved functionality. The digital medical revolution is rapidly being adopted in many medical centers, improving patient care and the success of the institution.

  10. HIS-PACS Coupling: First Experiences

    NASA Astrophysics Data System (ADS)

    Lodder, H.; van Weperen, J. H.; de Valk, J. P. J.; Bijl, K.; Bakker, A. R.; Helder, J. C.; Scharnberg, B.

    1988-06-01

    A first step has been made towards one of the ultimate goals of the so-called IMAGIS projects: the realization of a working PACS integrated with a Hospital Information System. This HIS-PACS coupling is part Of the Dutch Pacs project, a national PACS development program, supported by the Dutch Society of Radiology and funded by the Dutch government. This development is a cooperative effort of BAZIS (the Dutch Development and Support Group of the Hospital Information System 'ZIS'), the Utrecht University Hospital (AZU) and Philips International (Product Division Medical Systems) since 1986. In order to have a prototype HIS-PACS combination available as soon as possible, the three partners mentioned agreed on using a stepwise approach for carrying out the coupling project. For the first phase of the project we have restricted ourselves to: 1. the coupling of a specific HIS (BAZIS/ZIS) to a specific PACS (Philips/MARCOM) 2. only the in-patients of a particular ward of Internal Medicine 3. only one-way dataflow: from HIS to PACS, using a relatively slow link. This paper describes design criteria, technical solution chosen, message format and experimental set-up.

  11. Strategy of DIN-PACS benchmark testing

    NASA Astrophysics Data System (ADS)

    Norton, Gary S.; Lyche, David K.; Richardson, Nancy E.; Thomas, Jerry A.; Romlein, John R.; Cawthon, Michael A.; Lawrence, David P.; Shelton, Philip D.; Parr, Laurence F.; Richardson, Ronald R., Jr.; Johnson, Steven L.

    1998-07-01

    The Digital Imaging Network -- Picture Archive and Communication System (DIN-PACS) procurement is the Department of Defense's (DoD) effort to bring military medical treatment facilities into the twenty-first century with nearly filmless digital radiology departments. The DIN-PACS procurement is unique from most of the previous PACS acquisitions in that the Request for Proposals (RFP) required extensive benchmark testing prior to contract award. The strategy for benchmark testing was a reflection of the DoD's previous PACS and teleradiology experiences. The DIN-PACS Technical Evaluation Panel (TEP) consisted of DoD and civilian radiology professionals with unique clinical and technical PACS expertise. The TEP considered nine items, key functional requirements to the DIN-PACS acquisition: (1) DICOM Conformance, (2) System Storage and Archive, (3) Workstation Performance, (4) Network Performance, (5) Radiology Information System (RIS) functionality, (6) Hospital Information System (HIS)/RIS Interface, (7) Teleradiology, (8) Quality Control, and (9) System Reliability. The development of a benchmark test to properly evaluate these key requirements would require the TEP to make technical, operational, and functional decisions that had not been part of a previous PACS acquisition. Developing test procedures and scenarios that simulated inputs from radiology modalities and outputs to soft copy workstations, film processors, and film printers would be a major undertaking. The goals of the TEP were to fairly assess each vendor's proposed system and to provide an accurate evaluation of each system's capabilities to the source selection authority, so the DoD could purchase a PACS that met the requirements in the RFP.

  12. Epigenetic control of mitochondrial cell death through PACS1-mediated regulation of BAX/BAK oligomerization.

    PubMed

    Brasacchio, Daniella; Alsop, Amber E; Noori, Tahereh; Lufti, Mariam; Iyer, Sweta; Simpson, Kaylene J; Bird, Phillip I; Kluck, Ruth M; Johnstone, Ricky W; Trapani, Joseph A

    2017-06-01

    PCAF and ADA3 associate within the same macromolecular complexes to control the transcription of many genes, including some that regulate apoptosis. Here we show that PCAF and ADA3 regulate the expression of PACS1, whose protein product is a key component of the machinery that sorts proteins among the trans-Golgi network and the endosomal compartment. We describe a novel role for PACS1 as a regulator of the intrinsic pathway of apoptosis and mitochondrial outer membrane permeabilization. Cells with decreased PACS1 expression were refractory to cell death mediated by a variety of stimuli that operate through the mitochondrial pathway, including human granzyme B, staurosporine, ultraviolet radiation and etoposide, but remained sensitive to TRAIL receptor ligation. The mitochondria of protected cells failed to release cytochrome c as a result of perturbed oligomerization of BAX and BAK. We conclude that PCAF and ADA3 transcriptionally regulate PACS1 and that PACS1 is a key regulator of BAX/BAK oligomerization and the intrinsic (mitochondrial) pathway to apoptosis.

  13. Electronic publishing of the PAC95 proceedings

    SciTech Connect

    Gennari, L.T.; Siemann, R.H.

    1997-10-01

    The Particle Accelerator Conference (PAC) series has been a successful one with a steady rise in participation and in the size of the conference proceedings. The PAC conference proceeding are primary references for accelerator engineers and physicists, and their growth has created some problems. The main one is the efficient access to and use of the information in them. In light of this, and with the uncontrollable urge to do something new and different, they proposed to the PAC95 Organizing Committee that they publish this proceedings electronically. They accepted. This paper summarizes the adventure.

  14. Performance Evaluation of a Clinical PACS Module

    NASA Astrophysics Data System (ADS)

    Taira, Ricky K.; Cho, Paul S.; Huang, H. K.; Mankovich, Nicholas J.; Boechat, Maria I.

    1989-05-01

    Picture archiving and communication systems (PACS) are now clinically available in limited radiologic applications. The benefits, acceptability, and reliablity of these systems have thus far been mainly speculative and anecdotal. This paper discusses the evaluation of a PACS module implemented in the pediatric radiology section of a 700-bed teaching hospital. The PACS manages all pediatric inpatient images including conventional x-rays and contrast studies (obtained with a computed radiography system), magnetic resonance images, and relevant ultrasound images. A six-monitor workstation is available for image review.

  15. Lensing signals from spin-2 perturbations

    SciTech Connect

    Adamek, Julian; Durrer, Ruth; Tansella, Vittorio E-mail: ruth.durrer@unige.ch

    2016-01-01

    We compute the angular power spectra of the E-type and B-type lensing potentials for gravitational waves from inflation and for tensor perturbations induced by scalar perturbations. We derive the tensor-lensed CMB power spectra for both cases. We also apply our formalism to determine the linear lensing potential for a Bianchi I spacetime with small anisotropy.

  16. The angular momentum of the Oort cloud

    SciTech Connect

    Weissman, P.R. )

    1991-01-01

    An evaluation is made of the work of Marochnik et al. (1988), which estimated that the angular momentum of the Oort cloud is 2-3 orders of magnitude greater than the planetary system's total angular momentum. It is noted that most of the angular momentum in the currently observed Oort cloud is the result of the effects of external perturbers over the solar system's history, and it is demonstrated that the total current angular momentum is probably in the 6.0 x 10 to the 50th to 1.1 x 10 to the 51st g sq cm/sec range; original angular momentum was probably a factor of 5 below such values. 21 refs.

  17. The angular momentum of the Oort cloud

    NASA Technical Reports Server (NTRS)

    Weissman, Paul R.

    1991-01-01

    An evaluation is made of the work of Marochnik et al. (1988), which estimated that the angular momentum of the Oort cloud is 2-3 orders of magnitude greater than the planetary system's total angular momentum. It is noted that most of the angular momentum in the currently observed Oort cloud is the result of the effects of external perturbers over the solar system's history, and it is demonstrated that the total current angular momentum is probably in the 6.0 x 10 to the 50th to 1.1 x 10 to the 51st g sq cm/sec range; original angular momentum was probably a factor of 5 below such values.

  18. 24 CFR 891.735 - Notice upon PAC expiration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Notice upon PAC expiration. 891.735... and Individuals-Section 162 Assistance § 891.735 Notice upon PAC expiration. The PAC will provide that the Borrower will, at least 90 days before the end of the PAC contract term, notify each...

  19. 24 CFR 891.735 - Notice upon PAC expiration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Notice upon PAC expiration. 891.735... and Individuals-Section 162 Assistance § 891.735 Notice upon PAC expiration. The PAC will provide that the Borrower will, at least 90 days before the end of the PAC contract term, notify each...

  20. 24 CFR 891.735 - Notice upon PAC expiration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Notice upon PAC expiration. 891.735... and Individuals-Section 162 Assistance § 891.735 Notice upon PAC expiration. The PAC will provide that the Borrower will, at least 90 days before the end of the PAC contract term, notify each...

  1. 24 CFR 891.735 - Notice upon PAC expiration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Notice upon PAC expiration. 891.735... and Individuals-Section 162 Assistance § 891.735 Notice upon PAC expiration. The PAC will provide that the Borrower will, at least 90 days before the end of the PAC contract term, notify each...

  2. Pac-ing the Most into Genetics.

    ERIC Educational Resources Information Center

    Journet, Alan R. P.

    1984-01-01

    Describes the use of a Pac-Man model (called a Pactype) in teaching various genetics concepts. Indicates that students can learn to make predictions, analyze patterns of inheritance, and evaluate hypotheses before being introduced to the genetics vocabulary. (JN)

  3. Purchasing a PACS: from planning to procurement.

    PubMed

    2005-09-01

    Picture archiving and communication systems (PACS) are highly versatile data storage and retrieval systems that facilitate the transfer of digital images and patient data throughout a healthcare enterprise. They process images from diagnostic modalities and are interfaced to radiology information systems and hospital information systems to improve workflow. Ensuring that you select a PACS that is optimal for your facility requires planning and judgment. It also requires that you define your needs based on optimal workflow, clearly convey those needs to prospective suppliers, and organize responses for easy comparison. In this article, we outline the steps needed to prepare for a PACS purchase: (1) defining the scope of your PACS, (2) analyzing your workflow requirements so that you can plan workstation deployment, (3) ensuring adequate integration, (4) planning for your image-storage needs, (5) ensuring security, and (6) putting together an effective request for proposal.

  4. Preparing a cultural strategy for PACS.

    PubMed

    Lawrence, Paul

    2005-01-01

    Health Central Hospital in Ocoee, FL, performs in excess of 100,000 studies per year. In September 2003, it was determined that a picture archiving and communication system (PACS)--already an agenda item set for the current fiscal year-would have a go-live date of no later than July 1, 2004. That meant 9 months to research, develop, and implement the project. The objective was to bring PACS to fruition quickly and smoothly, have buy-in from all parties concerned, and not interrupt the daily flow of patient care in the process. The first step in the project was to select the vendors to be considered. Working closely with the radiology leadership team, a list of physicians who most frequently requested film was compiled. Among them, the team targeted 3 or 4 that it was believed would help champion the effort with their fellow physicians. Along with these pieces, the radiologists, physicians on staff at the hospital, and, of course, the nursing and administrative teams would be an integral part of the project. The groundwork was laid for hiring a consultant to assist in the process. A PACS coordinator job description was created. Then, a staff meeting was called to discuss routine business issues and bring PACS to the table. It is extremely important to bring all relative new data to the staff throughout the project. After that initial meeting, PACS was a regular agenda item. A project team was comprised of 6 persons from radiology, information systems (IS), and administration, as well as a radiologist. Each member was required to make all 4 site visits, give a brief written evaluation of the product seen, and provide a brief narrative for and against the equipment. The vendor was selected, a final proposal was obtained, and contract details were negotiated. A PACS Steering Committee was appointed, and a PACS coordinator and consultant were hired. The PACS was installed, and a computed radiography (CR) system was purchased and integrated with the PACS. Training was

  5. Overview of Polycyclic Aromatic Compounds (PAC).

    PubMed

    Achten, Christine; Andersson, Jan T

    2015-03-15

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs.

  6. Overview of Polycyclic Aromatic Compounds (PAC)

    PubMed Central

    Achten, Christine; Andersson, Jan T.

    2015-01-01

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs. PMID:26823644

  7. Making PACS the present, not the future.

    PubMed

    Hunt, D

    1998-01-01

    Why haven't you moved forward with PACS? Have you just procrastinated or does your facility have legitimate reasons? Some say the technology is too confusing or too new, while others say the cost of PACS is too high. Many facilities say they haven't found a satisfactory way to deal with the conflicting opinions of their radiologists, IS department, administration, referring physicians and staff. Take time to compare the technology you do understand with something familiar such as your own PC or perhaps the current networks inside your facility. You'll soon begin to see that PACS is not a new technology, but rather a new methodology. To handle the perceived high cost of PACS, remember that every facility has different needs. Look at your work flow and then the many byproducts of PACS, such as marketing. If you are the first in your area to implement this new technology, you'll gain a marketing advantage in competing for referring physicians and managed care referral business. Follow the process you use to purchase other products, such as CT or MRI, as you investigate the vendors. Finally, make a plan! Determine departmental goals and gather information from vendors. Create a timeline, a financial plan and your marketing strategy. Together, these steps will help move PACS into the present for you.

  8. Impact of PACS in hospital management

    NASA Astrophysics Data System (ADS)

    Hur, Gham; Cha, Soon-Joo; Kim, Yong H.; Hwang, Yoon J.; Kim, Soo Y.

    2002-05-01

    Since the low-cost, NT-based, full PACS was successfully implemented in a large-scale hospital at the end of 1999, many hospital administrators have rushed to purchase the system competitively. It is now a worldwide trend to implement the technology, but Korea has several unique environments for the fast spread of the full PACS. Since hospitals in Korea operate inpatient and outpatient clinics in the same building and use identical OCS, full integration of PACS with the OCS was relatively easy and highly efficient. The simple governing structures of the hospitals also made the decision-making process short and effective. In addition, the national health insurance reimbursement policy that started pay in the beginning of 2000 has also played a catalytic role for the swift propagation of PACS. The recent appearance of the affordable PACS gave hospital administrators the opportunity to learn and understand the role of digital imaging in the areas that are directly related to the efficiency and quality of medical services, as well as cost containment. Furthermore, PACS provided them with windows to the 'all-digital hospital,' which will lead them to realign policies in the management of the hospitals in order to compete successfully in the fast-changing world of health care.

  9. High strength distillery wastewater treatment by a PAC-MBR with low PAC dosage.

    PubMed

    Basu, Subhankar; Kaushik, Ankita; Saranya, P; Batra, Vidya S; Balakrishnan, Malini

    2016-01-01

    Augmentation of membrane bioreactors (MBRs) with activated carbon is established to offer several operational advantages. This work investigates the influence of low dosing (2 g/L) of powdered activated carbons (PACs) with different characteristics on the performance of MBR treating high strength molasses distillery wastewater containing difficult-to-biodegrade recalcitrant components. Two MBRs, augmented with different PACs, were operated in parallel over a period of 240 days and their performance monitored in terms of biomass growth, reduction in chemical oxygen demand (COD), sludge properties like extracellular polymeric substances content, filterability, and morphology. Removal of organics and coloring matter by adsorption, biodegradation and membrane filtration was estimated. Although adsorptive removal of color and COD is influenced by the properties of the PAC used, the performance of the PAC-MBRs was independent of PAC properties. Both PACs preferentially adsorbed the low molecular weight components in distillery wastewater. Retention by the membrane filter with the secondary cake layer contributed to reduction in color and COD of treated effluent. The findings indicate that low dosing with PAC adsorbing low molecular weight organics has a limited role in PAC-MBR treating distillery wastewater.

  10. Experience with high-performance PACS

    NASA Astrophysics Data System (ADS)

    Wilson, Dennis L.; Goldburgh, Mitchell M.; Head, Calvin

    1997-05-01

    Lockheed Martin (Loral) has installed PACS with associated teleradiology in several tens of hospitals. The PACS that have been installed have been the basis for a shift to filmless radiology in many of the hospitals. the basic structure for the PACS and the teleradiology that is being used is outlined. The way that the PACS are being used in the hospitals is instructive. The three most used areas for radiology in the hospital are the wards including the ICU wards, the emergency room, and the orthopedics clinic. The examinations are mostly CR images with 20 percent to 30 percent of the examinations being CT, MR, and ultrasound exams. The PACS are being used to realize improved productivity for radiology and for the clinicians. For radiology the same staff is being used for 30 to 50 percent more workload. For the clinicians 10 to 20 percent of their time is being saved in dealing with radiology images. The improved productivity stems from the high performance of the PACS that has been designed and installed. Images are available on any workstation in the hospital within less than two seconds, even during the busiest hour of the day. The examination management functions to restrict the attention of any one user to the examinations that are of interest. The examination management organizes the workflow through the radiology department and the hospital, improving the service of the radiology department by reducing the time until the information from a radiology examination is available. The remaining weak link in the PACS system is transcription. The examination can be acquired, read, an the report dictated in much less than ten minutes. The transcription of the dictated reports can take from a few hours to a few days. The addition of automatic transcription services will remove this weak link.

  11. Defining the PACS profession: an initial survey of skills, training, and capabilities for PACS administrators.

    PubMed

    Nagy, Paul; Bowers, George; Reiner, Bruce I; Siegel, Eliot L

    2005-12-01

    The need for specialized individuals to manage picture archiving and communications systems (PACS) has been recognized with the creation of a new professional title: PACS administrator. This position requires skill sets that bridge the current domains of radiology technologists (RTs), information systems analysts, and radiology administrators. Health care organizations, however, have reported difficulty in defining the functions that a PACS administrator should perform-a challenge compounded when the tries to combine this complex set of capabilities into one individual. As part of a larger effort to define the PACS professional, we developed an extensive but not exclusive consensus list of business, technical, and behavioral competencies desirable in the dedicated PACS professional. Through an on-line survey, radiologists, RTs, information technology specialists, corporate information officers, and radiology administrators rated the importance of these competencies. The results of this survey are presented, and the implications for implementation in training and certification efforts are discussed.

  12. Technology assessment of PACS in Osaka University Hospital.

    PubMed

    Inamura, K; Satoh, K; Kondoh, H; Mori, Y; Kozuka, T

    1994-05-01

    This paper describes a methodology of PACS technology assessment and gives examples of the results of measurement of 24 items of PACS-related situations of image diagnosis systems in Osaka University Hospital before a PACS is installed. These data are to be compared with the data which will be measured after PACS is installed in the new Osaka University Hospital, in order to complete our technology assessment. We propose common variables, units, and conditions of measurement, in order to establish a standard method of data comparison between before and after PACS installation in hospitals at large. We designed our PACS taking technology assessment into account. We do not stop the technology assessment at the efficacy evaluation, because PACS must be more than a tool for radiological practice. We extend the technology assessment into the effectiveness evaluation, so that PACS is a part of radiological practice itself, and diagnostic accuracy, economy and efficiency are the results of PACS operation.

  13. Automatic monitoring system for PACS management and operation

    NASA Astrophysics Data System (ADS)

    Zhang, Jianguo; Han, Ruolin; Wu, Dongqing; Zhang, Xiaoyan; Zhuang, Jun; Huang, H. K.

    2002-05-01

    In order to achieve the high and continuous availability in PACS operation, the PACS component status would be monitored seriously and quick responds would apply to the component if any failure happened to any PACS key component either in hardware or software level. In order to protect the data loss and also for security issue, the PACS data flow, e.g., from acquisition to final display, would be tracked carefully. All these measures will increase the total cost of ownership (TCO). We built an automatic monitoring system (AMS) on top of the PACS to assist the PACS management and to make the PACS component status and internal data flow more transparent to the administrators. The PACS AMS consists of two parts: monitoring agents running in each PACS component computer and a Monitor Server running in a remote computer. Monitoring agents are connected to all PACS processes running in each PACS component. The Monitor Server monitors each agent that allows the server to track the status of individual PACS process. The PACS managers can now monitor and control the entire PACS operation in real time, and also track patient and image data flow automatically.

  14. The PACS committee: the all-important human element.

    PubMed

    Reed, G; Reed, D H

    2001-01-01

    The PACS committee plays a crucial role in attaining successful outcomes from a PACS implementation. However, most radiology departments do not organize and manage their PACS committees well. This has resulted in poor outcomes and inability to realize projected benefits and return on investment. Ideally, there are two PACS committees: a high-level strategic committee that aligns the goals for the PACS with institutional initiatives, and an operational PACS committee that makes a hands-on approach to the project and manages the entire PACS program. The chairman of radiology, an assigned radiologist or the radiology administrator heads both PACS committees. The strategic PACS committee consists of senior people from information systems, strategic and operational planning, radiology, physicians, nursing, critical care, and other related departments in the hospital. The operational PACS committee consists of people directly involved in radiology operations including the chief of radiology, radiology administrator, technologists, file room manager and other personnel whose daily routines will be affected by the PACS implementation. The operational PACS committee manages the PACS program from initial planning through the post-installation period. Committee tasks include: developing an implementation plan, establishing goals and objectives, conducting a cost/benefits analysis, developing functional specifications, generating an RFP, managing vendor selection and contracting, preparing the site for installation, performing project management functions, conducting acceptance testing, overseeing training, and evolving the PACS operations to meet predicted outcomes.

  15. The PAC-MAN model: Benchmark case for linear acoustics in computational physics

    NASA Astrophysics Data System (ADS)

    Ziegelwanger, Harald; Reiter, Paul

    2017-10-01

    Benchmark cases in the field of computational physics, on the one hand, have to contain a certain complexity to test numerical edge cases and, on the other hand, require the existence of an analytical solution, because an analytical solution allows the exact quantification of the accuracy of a numerical simulation method. This dilemma causes a need for analytical sound field formulations of complex acoustic problems. A well known example for such a benchmark case for harmonic linear acoustics is the ;Cat's Eye model;, which describes the three-dimensional sound field radiated from a sphere with a missing octant analytically. In this paper, a benchmark case for two-dimensional (2D) harmonic linear acoustic problems, viz., the ;PAC-MAN model;, is proposed. The PAC-MAN model describes the radiated and scattered sound field around an infinitely long cylinder with a cut out sector of variable angular width. While the analytical calculation of the 2D sound field allows different angular cut-out widths and arbitrarily positioned line sources, the computational cost associated with the solution of this problem is similar to a 1D problem because of a modal formulation of the sound field in the PAC-MAN model.

  16. PERTURBING LIGNIFICATION

    USDA-ARS?s Scientific Manuscript database

    Perturbing lignification is possible in multiple and diverse ways. Without obvious growth/development phenotypes, transgenic angiosperms can have lignin levels reduced to half the normal level, can have compositions ranging from very high-guaiacyl/low-syringyl to almost totally syringyl, and can eve...

  17. Total quality approach to PACS software development and management

    NASA Astrophysics Data System (ADS)

    Valentino, Daniel J.; Taira, Ricky K.; Huang, Lu J.; Marciano, Donna M.; Manzo, William A.; Kangarloo, Hooshang

    1994-05-01

    A significant problem in building large-scale picture archiving and communications systems (PACS) is the production of reliable and accurate software, within a specified amount of time and cost, without impacting existing operations. PACS software management is particularly difficult because most PACS involve highly distributed processing over very heterogeneous components. We applied total quality management techniques to the problem of PACS software management. All potential users of PACS software were identified as `customers,' and we optimized the quality of service provided to them. Our methodology involves each of these customers at each stage of the software development cycle to help ensure that PACS functions meet the requirements and priorities of the majority of PACS users. We used this approach in rewriting major sections of key software modules in the UCLA PACS, resulting in code development within predictable periods of time at a predictable cost, thus enhancing our software development cycle.

  18. Perturbed particle disks. [planetary rings application

    NASA Technical Reports Server (NTRS)

    Borderies, N.; Goldreich, P.; Tremaine, S.

    1983-01-01

    The velocity ellipsoid in a particle disk near an isolated satellite resonance is determined by solving the Boltzmann moment equations, and solutions are obtained that are stationary functions of the azimuthal angle in a coordinate frame which rotates with the pattern speed of the perturbation potential. The magnitude of the deformation rate tensor in a perturbed particle disk is bounded from above by an expression which includes the orbital angular velocity, the optical depth, and a dimensionless constant of order unity. It is also found that, in sufficiently perturbed regions, there are ranges of azimuthal angle over which the radial component of the angular momentum flux is negative. It is also possible for the angular momentum luminosity to be negative. These results are pertinent to the understanding of sharp edges and density wave decay in planetary rings.

  19. Acceptance testing for PACS: from methodology to design to implementation

    NASA Astrophysics Data System (ADS)

    Liu, Brent J.; Huang, H. K.

    2004-04-01

    Acceptance Testing (AT) is a crucial step in the implementation process of a PACS within a clinical environment. AT determines whether the PACS is ready for clinical use and marks the official sign off of the PACS product. Most PACS vendors have Acceptance Testing (AT) plans, however, these plans do not provide a complete and robust evaluation of the full system. In addition, different sites will have different special requirements that vendor AT plans do not cover. The purpose of this paper is to introduce a protocol for AT design and present case studies of AT performed on clinical PACS. A methodology is presented that includes identifying testing components within PACS, quality assurance for both functionality and performance, and technical testing focusing on key single points-of-failure within the PACS product. Tools and resources that provide assistance in performing AT are discussed. In addition, implementation of the AT within the clinical environment and the overall implementation timeline of the PACS process are presented. Finally, case studies of actual AT of clinical PACS performed in the healthcare environment will be reviewed. The methodology for designing and implementing a robust AT plan for PACS was documented and has been used in PACS acceptance tests in several sites. This methodology can be applied to any PACS and can be used as a validation for the PACS product being acquired by radiology departments and hospitals. A methodology for AT design and implementation was presented that can be applied to future PACS installations. A robust AT plan for a PACS installation can increase both the utilization and satisfaction of a successful implementation of a PACS product that benefits both vendor and customer.

  20. 24 CFR 891.710 - Term of PAC.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Term of PAC. 891.710 Section 891... Individuals-Section 162 Assistance § 891.710 Term of PAC. The term of the PAC shall be 20 years. If the project is completed in stages, the term of the PAC for each stage shall be 20 years. The term of the...

  1. 24 CFR 891.710 - Term of PAC.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Term of PAC. 891.710 Section 891... Individuals-Section 162 Assistance § 891.710 Term of PAC. The term of the PAC shall be 20 years. If the project is completed in stages, the term of the PAC for each stage shall be 20 years. The term of the...

  2. 24 CFR 891.710 - Term of PAC.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Term of PAC. 891.710 Section 891... Individuals-Section 162 Assistance § 891.710 Term of PAC. The term of the PAC shall be 20 years. If the project is completed in stages, the term of the PAC for each stage shall be 20 years. The term of the...

  3. 24 CFR 891.710 - Term of PAC.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Term of PAC. 891.710 Section 891... Individuals-Section 162 Assistance § 891.710 Term of PAC. The term of the PAC shall be 20 years. If the project is completed in stages, the term of the PAC for each stage shall be 20 years. The term of the...

  4. 24 CFR 891.710 - Term of PAC.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Term of PAC. 891.710 Section 891... Individuals-Section 162 Assistance § 891.710 Term of PAC. The term of the PAC shall be 20 years. If the project is completed in stages, the term of the PAC for each stage shall be 20 years. The term of the...

  5. PACS: from planning to implementation for a new hospital facility

    NASA Astrophysics Data System (ADS)

    Meyers, Judith A.

    2001-08-01

    Planning PACS for a new hospital facility is an enormous undertaking with many varied user opinions. A pure objective-oriented planning approach was utilized along with a small PACS core planning team. The small PACS core team consisted of owner representation (administration), user representation (radiologists) and the PACS consultant. The overall PACS planning process was broken down into segments. Each segmented represented a key milestone for PACS planning with a set of clear objectives. The PACS core team followed a schedule beginning with preliminary PACS information moving forward to bid specification. An important element in PACS planning was the development of a PACS Component Location Matrix. The matrix was developed from the architectural plans for the new hospital and provided a guideline for everyone including architects and engineers. The matrix included CAD system identification number, location by architectural room number, room name, component network, remote diagnostics and storage. After a year of planning the PACS system and acceptance of vendor bid, the implementation process was ready to begin. The same small PACS core planning team remains intact for the implementation phase of the project.

  6. Power Pacs for Teaching Home Economics Related Science and Math.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Div. of Vocational Education.

    This guide contains materials designed to assist teachers and students in home economics related courses with mastery of job-related mathematics, science, and behavioral science. The 40 Power Pacs are divided into mathematics (16 Power Pacs), science (15), and behavioral science (9). Each Power Pac contains teacher materials and student materials.…

  7. Cost justification of filmless PACS and national policy

    NASA Astrophysics Data System (ADS)

    Lim, Jae H.

    2002-05-01

    The expense of installing PACS is high so most Korean hospitals cannot afford to purchase the system easily. We can justify the cost of PACS by considering the visible and invisible benefits. As a visible benefit we can save the cost of films and equipments for film processing. Invisible benefits of PACS is the cost of film handling. Generally, doctors spend some 25 minutes in handling X-ray films everyday and they spend 10 days (84 hours) throughout a year. Radiology technicians, nurses, orderlies and clerks also handle films and the total salary for handling films by doctors and paramedics will be considerable. Considering the visible and invisible benefits, cost of PACS is justified and PACS can be installed in every hospital, whatever their size. The Korean Society of PACS tried to make reimbursement of the cost of PACS and persuaded the government officers and eventually the Ministry of Health and Welfare decided to reimburse the use of PACS in hospitals. Based on the money reimbursed, general hospitals or university hospitals will earn enough money to purchase a PACS in 3 - 5 years. After the Korean government started to reimburse the cost of PACS, many hospitals wanted to install PACS and the number of hospitals installing PACS is soaring.

  8. Direct Observation of "Pac-Man" Coarsening.

    PubMed

    Yu, X X; Gulec, A; Yoon, A; Zuo, J M; Voorhees, P W; Marks, L D

    2017-08-09

    We report direct observation of a "Pac-Man" like coarsening mechanism of a self-supporting thin film of nickel oxide. The ultrathin film has an intrinsic morphological instability due to surface stress leading to the development of local thicker regions at step edges. Density functional theory calculations and continuum modeling of the elastic instability support the model for the process.

  9. A Pair of Pac-Men

    NASA Image and Video Library

    2012-11-26

    Scientists with NASA Cassini mission have spotted two features shaped like the 1980s video game icon Pac-Man on moons of Saturn. One was observed on the moon Mimas in 2010 and the latest was observed on the moon Tethys.

  10. Medical imaging, PACS, and imaging informatics: retrospective.

    PubMed

    Huang, H K

    2014-01-01

    Historical reviews of PACS (picture archiving and communication system) and imaging informatics development from different points of view have been published in the past (Huang in Euro J Radiol 78:163-176, 2011; Lemke in Euro J Radiol 78:177-183, 2011; Inamura and Jong in Euro J Radiol 78:184-189, 2011). This retrospective attempts to look at the topic from a different angle by identifying certain basic medical imaging inventions in the 1960s and 1970s which had conceptually defined basic components of PACS guiding its course of development in the 1980s and 1990s, as well as subsequent imaging informatics research in the 2000s. In medical imaging, the emphasis was on the innovations at Georgetown University in Washington, DC, in the 1960s and 1970s. During the 1980s and 1990s, research and training support from US government agencies and public and private medical imaging manufacturers became available for training of young talents in biomedical physics and for developing the key components required for PACS development. In the 2000s, computer hardware and software as well as communication networks advanced by leaps and bounds, opening the door for medical imaging informatics to flourish. Because many key components required for the PACS operation were developed by the UCLA PACS Team and its collaborative partners in the 1980s, this presentation is centered on that aspect. During this period, substantial collaborative research efforts by many individual teams in the US and in Japan were highlighted. Credits are due particularly to the Pattern Recognition Laboratory at Georgetown University, and the computed radiography (CR) development at the Fuji Electric Corp. in collaboration with Stanford University in the 1970s; the Image Processing Laboratory at UCLA in the 1980s-1990s; as well as the early PACS development at the Hokkaido University, Sapporo, Japan, in the late 1970s, and film scanner and digital radiography developed by Konishiroku Photo Ind. Co. Ltd

  11. RIS requirements to support a PACS infrastructure

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Frost, Meryll M.; Moser, Robert; Huda, Walter; Staab, Edward V.

    1996-05-01

    The purpose of this research and development effort was to solve several image management problems in Picture Archiving and Communications Systems (PACS). First, the patient and study information associated with images was not always correct and only rarely complete. This was due to human error in entering information on a console, and from incomplete data entry forms on image producing equipment. Second, in at least one area, Computed Radiography, the task of data entry was so time consuming that throughput suffered. The third problem was image routing, both within the Department of Radiology and throughout the hospital. The last identified problem was the lack of a common key between the PACS database the Radiology Information System (RIS) database so reports and images could be associated with each other. An RIS/PACS interface was developed in which RIS packets were sent to a PACS process at the time request forms were printed. These packets were parsed to various acquisition computers based on the modality type where they were stored in a MSQL Database for use in validating studies as they were completed prior to being transferred to PACS. DICOM header information from incoming studies were `matched' to a database entry based on the medical record number and modality. Whenever possible, an additional match was made on an accession number stored in the header. A match could result in the DICOM header being completed with detailed information about the patient, patient location, requesting service, and the procedure or study. In the case of the Kodak CR unit, patient and study information were sent directly to the CR workstation where they were accessible using a bar code interface at the time plates were ready to be processed. Routing within the radiology department was determined by comparing the RIS procedure code with an MSQL table to locate the workstation(s) used for viewing this type of study. The data of birth was used to determine whether the study

  12. Experience In The Integration Of A Nuclear Medicine PACS Into A PACS Radiology System

    NASA Astrophysics Data System (ADS)

    Tobes, Michael C.; Stahl, Theodore J.; Dasika, Rao

    1988-06-01

    A local Picture Archiving and Communication System (PACS) has been operational in the Division of Nuclear Medicine at Robert Wood Johnson University Hospital for the past five years. Recently, it has been interfaced to a total PACS which is based on different hardware and software. Using this hybrid system, we describe our initial efforts to facilitate the short and long term archiving of NM studies and the use of combined image displays for correlative image analysis.

  13. Cost-effective ultrasound PACS solution

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Frost, Meryll M.; Staab, Edward V.

    1995-05-01

    Picture archiving and communication systems (PACS) have been quite successful at the University of Florida in the areas of CT, MR, and nuclear medicine. In each case, although we have not always been able to provide the optimal level of performance, we have been able to solve a problem and the systems are used extensively. Ultrasound images are required in a number of locations and the multiformat camera print capability was no longer adequate for the growing volume in the ultrasound section. Although we were certain we could successfully implement PACS for ultrasound, new forces in health care dictate that we justify our system in terms of cost. We analyzed the feasibility of a PACS solution for ultrasound and designed a system that meets our needs and is cost effective. We evaluated the ultrasound operation in terms of image acquisition patterns and throughput requirements. An inventory of existing and PACS equipment was made to determine the feasibility of interfacing the two systems. Commercial systems were evaluated for functionality and cost and a system was designed to meet our needs. The only way to achieve our goal of installing a cost effective ultrasound PACS was to eliminate film and use the cost savings to offset the cost of new equipment and development. We designed a system that could be produced using inexpensive components and existing hardware and software to meet our needs. A commercial vendor was chosen to provide the ultrasound acquisition. The Radiology Information System interface used at the University provides the necessary data to build a DICOM header, and an existing DICOM server routes the images to the appropriate workstations, archives, and printers. Additional storage is added to an existing archive to accommodate the ultrasound images and two existing workstations are evaluated for use in ultrasound.

  14. PACS economics and the referring physician

    NASA Astrophysics Data System (ADS)

    Saarinen, Allan O.; Wilson, M. C.; Iverson, Scott C.; Haynor, David R.; Loop, John W.

    1990-08-01

    One of the touted potential benefits of Picture Archive and Communications Systems (PACS) is that these systems will save referring physicians significant time by eliminating their trips to andfrom the radiology departmentfile room. To date, this potential savings has not been quantified in any hospital setting. Economic modeling of PACS by the University of Washington demonstrates that the cost savings of PACS is extremely sensitive to small productivity changes in referring physician time savings. To provide analytical strength to this argument and supportfor the overall importance of the referring physician in PACS economics, trip distribution data was collected at the University to determine the average time referring physicians spend traveling to andfrom the radiology departmentfile room. This travel time is significant and it corroborates other work by the authors suggesting the benefits of PACS may be, in fact, larger outside the radiology department than inside it. Information for this study was obtained from two sources. In one case, referring physicians were queried about the time they and their support staffspend requesting and retrievingfilmfilesfrom thefile room by using a comprehensive hospital-wide survey. In the second case, the distance between all major clinics in the University medical center and the number offilm files each clinic checks out weekly were entered into a conventional transportation trip distribution model toforecast the time staffspend on this activity. While some differences in the results occurredfrom the two cases, each case generally showed a significant expenditure of effort approaching approximately two-weeks per year per referring physician with a potential recovery value of between 3 to 8 million dollars annually in additional billable revenue, assuming adequate patient demand.

  15. Assessing PAC contribution to the NOM fouling control in PAC/UF systems.

    PubMed

    Campinas, Margarida; Rosa, Maria João

    2010-03-01

    This paper investigates the powdered activated carbon (PAC) contribution to the fouling control by natural organic matter (NOM) in PAC/UF hybrid process, as well as the foulant behaviour of the PAC itself. Solutions of NOM surrogates (humic acids, AHA, and tannic acid, TA) and AOM/EOM (algogenic organic matter/extracellular organic matter) fractions from a Microcystis aeruginosa culture were permeated through an ultrafiltration (UF) hollow-fibre cellulose acetate membrane (100kDa cut-off). The greatest impairment on flux and the poorest rejection were associated with polysaccharide-like EOM substances combined with mono and multivalent ions. PAC, either in the absence or in the presence of NOM, did not affect the permeate flux nor the reversible membrane fouling, regardless of the NOM characteristics (hydrophobicity and protein content) and water inorganics. However, PAC controlled the irreversible membrane fouling, minimising the chemical cleaning frequency. Furthermore, PAC enhanced AHA and TA rejections and the overall removal of AOM, although it was apparently ineffective for the highly hydrophilic EOM compounds. Copyright 2009 Elsevier Ltd. All rights reserved.

  16. PACS experience at the University of Hokkaido Medical School

    NASA Astrophysics Data System (ADS)

    Irie, Goro; Miyasaka, Kazuo; Miyamoto, Kenji; Kojima, Tetsuhumi; Yamamoto, Isao; Kudo, Toshihiko

    1990-08-01

    Seven months experiences of a filmless PACS (named HU-PACS) which covers Radiology, Orthopedic, Internal medicine and General Surgery departments are reported. The PACS has only 20 Image terminals but handles more than 50% of images produced which is about 1000 images per working day. Physicians of the departments have many criticisms and opinions on the PACS but generally speaking it is well accepted and inspiring the physicians to improve the PACS in its image quality and other functions instead of being discarded. Preliminary clinical assessment are performed and reported also.

  17. Future trends in picture archiving and communication system (PACS)

    NASA Astrophysics Data System (ADS)

    Al-Hajeri, Mona; Clarke, Malcolm

    2015-03-01

    Objective: This research investigates the needs and opinions of radiologists on the use of enhanced information technologies and approaches to improve the functionality of Picture Archiving and Communication Systems (PACS). Method: Six interviews were conducted in the main governmental hospital in Kuwait (AL-Sabah Hospital) with radiologists, including two senior radiologists, two junior radiologists, and two trainee radiologists undertaking the Irish radiology board. Results: The radiologists identified a number of limitations that exist in current PACS and requirements to enhance usability and functionality. However, it was the case that some of the radiologists had little knowledge about the advanced trends in PACS. Four themes emerged from the thematic analysis of the data: (1) limitations of traditional PACS; (2) Features and requirements that can increase PACS functionality; (3) web based solutions of PACS; (4) PACS in mobile phones. Conclusion: It is widely recognized that PACS has limitations. This research has identified themes that, when incorporated, will enhance the functionality of PACS and provide better quality clinical practice. This research has determined the important future trends of PACS. Primarily web based solutions and use in mobile phones. The findings from this research can be used as recommendations to vendors, for product development and medical institutes to consider when undertaking implementation of PACS and training future radiologists.

  18. The importance of a picture archiving and communications system (PACS) manager for large-scale PACS installations.

    PubMed

    Beird, L C

    1999-05-01

    Installing a picture archiving and communication system (PACS) is a massive undertaking for any radiology department. Facilities making a successful transition to digital systems are finding that a PACS manager helps guide the way and offers a heightened return on the investment. The PACS manager fills a pivotal role in a multiyear, phased PACS installation. PACS managers navigate a facility through the complex sea of issues surrounding a PACS installation by coordinating the efforts of the vendor, radiology staff, hospital administration, and the information technology group. They are involved in the process from the purchase decision through the design and implementation phases. They can help administrators justify a PACS, purchase and shape the request for proposal (RFP) process before a vendor is even chosen. Once a supplier has been selected, the PACS manager works closely with the vendor and facility staff to determine the best equipment configuration for his or her facility, and makes certain that all deadlines are met during the planning and installation phase. The PACS manager also ensures that the infrastructure and backbone of the facility are ready for installation of the equipment. PACS managers also help the radiology staff gain acceptance of the technology by serving as teachers, troubleshooters, and the primary point-of-contact for all PACS issues. This session will demonstrate the value of a PACS manager, as well as point out ways to determine the manager's responsibilities. By the end of the session, participants will be able to describe the role of a PACS manager as it relates to departmental operation and in partnership with equipment vendors, justify a full-time position for a PACS manager, and identify the qualifications of candidates for the position of PACS manager.

  19. On Angular Momentum

    DOE R&D Accomplishments Database

    Schwinger, J.

    1952-01-26

    The commutation relations of an arbitrary angular momentum vector can be reduced to those of the harmonic oscillator. This provides a powerful method for constructing and developing the properties of angular momentum eigenvectors. In this paper many known theorems are derived in this way, and some new results obtained. Among the topics treated are the properties of the rotation matrices; the addition of two, three, and four angular momenta; and the theory of tensor operators.

  20. Gyroscope test of gravitation: An analysis of the important perturbations

    NASA Technical Reports Server (NTRS)

    Oconnell, R. F.

    1971-01-01

    Two perturbations, the earth's quadrupole moment and the earth's revolution around the sun, are discussed. Schiff's proposed gyroscope test of gravitation is analyzed, along with the capability of deciphering each separate contribution to the angular velocity of spin precession.

  1. Gyroscope test of gravitation: An analysis of the important perturbations

    NASA Technical Reports Server (NTRS)

    Oconnell, R. F.

    1971-01-01

    Two perturbations, the earth's quadrupole moment and the earth's revolution around the sun, are discussed. Schiff's proposed gyroscope test of gravitation is analyzed, along with the capability of deciphering each separate contribution to the angular velocity of spin precession.

  2. PACS administrators' and radiologists' perspective on the importance of features for PACS selection.

    PubMed

    Joshi, Vivek; Narra, Vamsi R; Joshi, Kailash; Lee, Kyootai; Melson, David

    2014-08-01

    Picture archiving and communication systems (PACS) play a critical role in radiology. This paper presents the criteria important to PACS administrators for selecting a PACS. A set of criteria are identified and organized into an integrative hierarchical framework. Survey responses from 48 administrators are used to identify the relative weights of these criteria through an analytical hierarchy process. The five main dimensions for PACS selection in order of importance are system continuity and functionality, system performance and architecture, user interface for workflow management, user interface for image manipulation, and display quality. Among the subdimensions, the highest weights were assessed for security, backup, and continuity; tools for continuous performance monitoring; support for multispecialty images; and voice recognition/transcription. PACS administrators' preferences were generally in line with that of previously reported results for radiologists. Both groups assigned the highest priority to ensuring business continuity and preventing loss of data through features such as security, backup, downtime prevention, and tools for continuous PACS performance monitoring. PACS administrators' next high priorities were support for multispecialty images, image retrieval speeds from short-term and long-term storage, real-time monitoring, and architectural issues of compatibility and integration with other products. Thus, next to ensuring business continuity, administrators' focus was on issues that impact their ability to deliver services and support. On the other hand, radiologists gave high priorities to voice recognition, transcription, and reporting; structured reporting; and convenience and responsiveness in manipulation of images. Thus, radiologists' focus appears to be on issues that may impact their productivity, effort, and accuracy.

  3. A PACS maturity model: a systematic meta-analytic review on maturation and evolvability of PACS in the hospital enterprise.

    PubMed

    van de Wetering, Rogier; Batenburg, Ronald

    2009-02-01

    With PACS and medical imaging technology maturing, the importance of organizational maturity and effective deployment of PACS in the hospital enterprise are becoming significant. The objective of this paper is twofold. Firstly, PACS literature on maturity and evolvability in the hospital enterprise is analyzed, resulting in an overview of the relevant developments concerning maturity of PACS. Secondly, this paper looks at the development of a maturity model for PACS technology. Using structured search queries, we identified 34 papers reporting relevant aspects of maturity and evolvability of PACS. From the results of a meta-analytic review on PACS maturity and evolvability, we propose a model--the PACS maturity model (PMM)--that describes five levels of PACS maturity and the corresponding process focus. We argue that this model can help hospitals to gain insights into their (strategic) objectives for growth and maturity with regard to PACS, the electronic patient record (EPR) and other health information systems. Moreover, the proposed model can be applied as a valuable tool for organizational assessments, monitoring and benchmarking purposes. Hence, the PMM contributes to an integral alignment model for PACS technology.

  4. Evaluation of PACS in a multihospital environment

    NASA Astrophysics Data System (ADS)

    Siegel, Eliot L.; Reiner, Bruce I.; Protopapas, Zenon

    1998-07-01

    Although a number of authors have described the challenges and benefits of filmless operation using a hospital-wide Picture Archival and Communication System (PACS), there have been few descriptions of a multi-hospital wide area PACS. The purpose of this paper is to describe our two and a half year experience with PACS in an integrated multi-facility health care environment, the Veterans Affairs Maryland Health Care System (VAMHCS). On June 17, 1995 the Radiology and Nuclear Medicine services became integrated for four medical centers forming the VA Maryland Health Care System creating a single multi-facility imaging department. The facilities consisted of the Baltimore VA (acute and outpatient care, tertiary referral center), Ft. Howard (primarily long term care), Perry Point (primarily psychiatric care), and the Baltimore Rehabilitation and extended care facility (nursing home). The combined number of studies at all four sites is slightly more than 80,000 examinations per year. In addition to residents and fellows, the number of radiologists at Baltimore was approximately seven, with two at Perry Point, one at Ft. Howard, and no radiologists at the Rehabilitation and Extended Care facility. A single HIS/RIS, which is located physically at the Baltimore VAMC is utilized for all four medical centers. The multi- facility image management and communication system utilizes two separate PAC Systems that are physically located at the Baltimore VA Medical Center (BVAMC). The commercial system (GE Medical Systems) has been in place in Baltimore for more than 41/2 years and is utilized primarily in the acquisition, storage, distribution and display of radiology and nuclear medicine studies. The second PACS is the VISTA Imaging System, which has been developed as a module of the VA's HIS/RIS by and for the Department of Veterans Affairs. All of the radiology images obtained on the commercial PACS are requested by the VISTA Imaging System using DICOM query/retrieve commands

  5. Ultrareliable PACS: design and clinical evaluation

    NASA Astrophysics Data System (ADS)

    Goble, John C.; Kronander, Torbjorn; Wilske, Nils-Olof; Yngvesson, Jonas T.; Ejderholm, Henrik; Ekstrom, Marie

    1999-07-01

    We describe our experience in the design, installation and clinical evaluation o fan ultra-reliable PACS - a system in which the fundamental design constraint was system availability. This syste has ben constructed using commercial, off-the-shelf hardware and software, using an open system, standards-based approach. The system is deployed in the film-free Department of Pediatric Radiology at the Astrid Lindgren Barnsjukhus a nit of the Karolinska Institute in Stockholm, Sweden.

  6. NMMC Picture Archiving and Communication Systems (PACS)

    DTIC Science & Technology

    2008-07-01

    prescribed antibiotics and an inhaler for bronchitis. The radiologist interpreted the CXR as “unremarkable chest.” None – would also treat these...clinical symptoms with antibiotics and an inhaler 2 The PCP interpreted the CXR of 6 yo female who is on a return visit for her bad cough as “a...state “no new infiltrate.” No change in care. Levoquin is appropriate for coronary obstructive pulmonary disease ( COPD ) exacerbation. Post-PACS

  7. Patriot Advanced Capability-3 (PAC-3)

    DTIC Science & Technology

    2013-12-01

    conducted a successful missile flight test to intercept a Zombie test missile at White Sands Missile Range (WSMR), New Mexico. This was the first flight...test with the Zombie target, designed to substantially reduce the cost of Tactical Ballistic Missile (TBM) targets and provide threat...PAC-3 missiles were ripple fired to engage the Zombie target. In addition to demonstrating Zombie performance, this test demonstrated the Patriot

  8. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  9. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  10. Image flow management in a PACS network

    NASA Astrophysics Data System (ADS)

    Chen, Doris T.; Ho, Bruce K. T.; Chao, Woodrew; Taira, Ricky K.

    1994-05-01

    The purpose of this project is to develop a graphical tool to analyze and optimize the image flow pattern in a hierarchical, large scale PACS local area network. The PACS network is characterized as heavy image traffic, long image flow path, heterogeneous computer nodes, multiple protocols, and physical media. A smooth operation of the PACS network depends on a centralized, timely report of image flow pattern, trouble spots, and an alarm mechanism for critical conditions. Crucial timing parameters such as queue delay from acquisition to display, processing time for archiving and reformatting, and retrieval speed, can be locally collected and reported to the network manager for statistical characterization. Moreover, network traffic information and system component failures anywhere in the image flow can be reported graphically. High urgency failure trigger an immediate alarm to the designed operator. Our network management software with user friendly graphical interface is easy to use even by non-computer personnel such as hospital administrators. It achieves total automation in trouble reporting and thus leads to improvement of the network layout and operation condition based on the analysis of image flow pattern.

  11. Investment alternative: the status quo or PACS?

    NASA Astrophysics Data System (ADS)

    Vanden Brink, John A.; Cywinski, Jozef K.

    1990-08-01

    While the cost of Picture Archiving and Communication Systems (PACS) can be substantial, the cost of continuing with present manual methods may become prohibitive in growing departments as the need for additional space and personnel (both technical and professional) to meet the increasing requirements for all image management activities continues to grow. This will occur simultaneously with increasing pressures on problems of the present system, i.e., lost films, lost revenues, delayed reporting and longer diagnostic cycle times. Present methods of image archiving communication and management i.e. the relationship of procedure volume to VFE requirements for professional and technical personnel, costs of film, film storage space, and other performance factors are analyzed based on the database created by the Technology Marketing Group (TMG) computerized cost analysis model applied to over 50 US hospitals. Also, the model is used to provide the projected cost of present methods of film management for an average US 400 +bed hospital based on ten year growth rate assumptions. TMG PACS Tracking data provides confirmation of staffmg pattern correlation to procedure volume. The data presented in the paper provides a basis for comparing the investment in maintaining the status quo to an investment in PACS.

  12. Methodology for the economic assessment of PACS

    NASA Astrophysics Data System (ADS)

    Langlotz, Curtis P.; Even-Shoshan, Orit; Seshadri, Sridhar B.; Brikman, Inna; Kishore, Sheel; Kundel, Harold L.; Schwartz, J. Sanford

    1994-05-01

    Most economic studies of Picture Archiving and Communications Systems (PACS) to date, including our own, have focused on the perspective of the radiology department and its direct costs. However, many researchers have suggested additional cost savings that may accrue to the medical center as a whole through increased operational capacity, fewer lost images, rapid simultaneous access to images, and other decreases in resource utilization. We describe here a new economic analysis framework we have developed to estimate these potential additional savings. Our framework is comprised of two parallel measurement methods. The first method estimates the cost of care actually delivered through online capture of charge entries from the hospital's billing computer and from the clinical practices' billing database. Multiple regression analyses will be used to model cost of care, length of stay, and other estimates of resource utilization. The second method is the measurement of actual resource utilization, such as technologist time, frequency and duration of film searches, and equipment utilization rates. The costs associated with changes in resource use will be estimated using wage rates and other standard economic methods. Our working hypothesis is that, after controlling for the underlying clinical and demographic differences among patients, patients imaged using a PACS will have shorter lengths of stay, shorter exam performance times, and decreased costs of care. We expect our analysis framework to explain and resolve some of the conflicting views of the cost-effectiveness of PACS.

  13. Migration of medical image data archived using mini-PACS to full-PACS.

    PubMed

    Jung, Haijo; Kim, Hee-Joung; Kang, Won-Suk; Lee, Sang-Ho; Kim, Sae-Rome; Ji, Chang Lyong; Kim, Jung-Han; Yoo, Sun Kook; Kim, Ki-Hwang

    2004-06-01

    This study evaluated the migration to full-PACS of medical image data archived using mini-PACS at two hospitals of the Yonsei University Medical Center, Seoul, Korea. A major concern in the migration of medical data is to match the image data from the mini-PACS with the hospital OCS (Ordered Communication System). Prior to carrying out the actual migration process, the principles, methods, and anticipated results for the migration with respect to both cost and effectiveness were evaluated. Migration gateway workstations were established and a migration software tool was developed. The actual migration process was performed based on the results of several migration simulations. Our conclusions were that a migration plan should be carefully prepared and tailored to the individual hospital environment because the server system, archive media, network, OCS, and policy for data management may be unique.

  14. Secure vendor environment (SVE) for PACS

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice; Frost, Meryll

    2005-04-01

    A Secure Vendor Environment (SVE) was created to protect radiology modalities from network intrusion, worms, viruses, and other forms of damaging attacks. Many vendors do not attempt any form of network security and if an institution demands a non-standard and secure installation, a future system upgrade could and frequently does eliminate any security measures installed during the initial installation. The SVE isolates the vendor equipment behind a virtual firewall on a private network that is invisible to the outside world. All interactions must go though a device containing two network interface cards called an Application Processor that acts as a store-and forward router, performs DICOM repair, proxies modality worklist, and isolates the vendor modalities. A small VPN appliance can open the device temporarily for remote access by vendor engineers. Prior to the routine installation of the SVE, vendor equipment was often attacked by hostile network intruders and viruses or worms, sometimes rendering the equipment unusable until the vendor could reload the system. The resulted in considerable clinical downtime and loss of revenue. Since the relatively low cost SVE solution has routinely been installed with all new equipment, no intrusions have occurred, although our network sniffers and intrusion detectors indicate that we are constantly being scanned for vulnerability. Purpose: To provide a secure network for vendor equipment in a PACS environment while allowing vendor access for upgrades and system repairs. Method: The network administrators at our university believe that network security should be implemented at the machine level rather than relying on a firewall. A firewall solution could conceivably block unwanted intrusion from outside the university network, but would still allow literally thousands of potential network users to get through to the PACS network. All the PACS archive, display and routing systems are individually protected from intrusion, but

  15. Benzene removal by PAC in jet flocculation system

    SciTech Connect

    Sobrinho, J.A.H.; Thiem, L.T.; Alkhatib, E.A.

    1997-10-01

    A jet flocculator/powdered activated carbon (PAC) adsorption pilot plant was designed, built, and operated in order to evaluate a water treatment process capable of simultaneous adsorption of benzene and flocculation of PAC and silica clay particles. The jet flocculation/PAC system successfully combined, in the same reactor, flocculation of suspended solids by using jet mixing, solids retention using pall rings, and benzene removal by PAC adsorption. The advantages of this process included operational simplicity, reliability, and low energy consumption. The jet flocculator/PAC adsorption system was able to achieve suspended solids and benzene removals of approximately 80 and 95%, respectively, from an influent containing 70 mg/L of suspended solids (silica clay and PAC) and 100 {micro}g/L of benzene.

  16. DVL Angular Velocity Recorder

    NASA Technical Reports Server (NTRS)

    Liebe, Wolfgang

    1944-01-01

    In many studies, especially of nonstationary flight motion, it is necessary to determine the angular velocities at which the airplane rotates about its various axes. The three-component recorder is designed to serve this purpose. If the angular velocity for one flight attitude is known, other important quantities can be derived from its time rate of change, such as the angular acceleration by differentiations, or - by integration - the angles of position of the airplane - that is, the angles formed by the airplane axes with the axis direction presented at the instant of the beginning of the motion that is to be investigated.

  17. Current status of the UCSF second-generation PACS

    NASA Astrophysics Data System (ADS)

    Huang, H. K.; Arenson, Ronald L.; Wong, Albert W. K.; Bazzill, Todd M.; Lou, Shyhliang A.; Andriole, Katherine P.; Wang, Jun; Zhang, Jianguo; Wong, Stephen T. C.

    1996-05-01

    This paper describes the current status of the second generation PACS at UCSF commenced in October 1992. The UCSF PACS is designed in-house as a hospital-integrated PACS based on an open architecture concept using industrial standards including UNIX operating system, C programming language, X-Window user interface, TCP/IP communication protocol, DICOM 3.0 image standard and HL7 health data format. Other manufacturer's PACS components which conform with these standards can be easily integrated into the system. Relevant data from HIS and RIS is automatically incorporated into the PACS using HL7 data format and TCP/IP communication protocol. The UCSF system also takes advantage of state-of-the-art communication, storage, and software technologies in ATM, multiple storage media, automatic programming, multilevel processes for a better cost-performance system. The primary PACS network is the 155 Mbits/sec OC3 ATM with the Ethernet as the back-up. The UCSF PACS also connects Mt. Zion Hospital and San Francisco VA Medical Center in the San Francisco Bay area via an ATM wide area network with a T1 line as the back-up. Currently, five MR and five CT scanners from multiple sites, two computed radiography systems, two film digitizers, one US PACS module, the hospital HIS and the department RIS have been connected to the PACS network. The image data is managed by a mirrored database (Sybase). The PACS controller, with its 1.3 terabyte optical disk library, acquires 2.5 gigabytes digital data daily. Four 2K, five, 1,600-line multiple monitor display workstations are on line in neuroradiology, pediatric radiology and intensive care units for clinical use. In addition, the PACS supports over 100 Macintosh users in the department and selected hospital sites for both images and textual retrieval through a client/server mechanism. We are also developing a computation and visualization node in the PACS network for advancing radiology research.

  18. Modeling The Economics Of PACS: What Is Important?

    NASA Astrophysics Data System (ADS)

    Saarinen, Allan O.; Haynor, David R.; Loop, John W.; Johnson, Linda; Russell, John; Mitchell, Kate; Nemerever, Marilyn

    1989-05-01

    Picture Archive and Communications Systems (PACS) represent a significant long term capital investment for radiology departments and hospitals. Many radiology departments want to acquire this new imaging technology, but they are still concerned about the cost of these systems. While a few studies have tried to quantify the costs and benefits of PACS, these studies have been limited in scope. The University of Washington is evaluating a Digital Imaging Network System (DINS) and PACS for the U.S. Army Medical Research and Development Command. Part of this evaluation includes developing a comprehensive cost model of PACS for one of the military's large health care facilities (a 400 bed hospital). The paper summarizes the methodology and multi-layered spreadsheet model developed at the University to forecast the costs and potential cost savings this health care facility might accrue if a hospital wide PACS is installed and film is eliminated. It also discusses the many important assumptions made in the model. A sensitivity analysis of the model is also presented. The model indicates that keeping PACS maintenance costs down is particularly critical to the cost effectiveness of PACS. That is, the film cost savings attributed to PACS can be largely offset by PACS equipment maintenance cost. The cost effectiveness of PACS will also hinge upon whether a number of intangible benefits, such as referring physician and support staff productivity gains can be attributed to PACS. This model also suggests that the pay back period for a hospital wide PACS will vary significantly dependent upon the mix of tangible versus intangible cost savings incorporated into the modeling process.

  19. 78 FR 57671 - PacWest Equities, Inc.; Order of Suspension of Trading

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... COMMISSION PacWest Equities, Inc.; Order of Suspension of Trading September 17, 2013. It appears to the... securities of PacWest Equities, Inc. (``PacWest'') because of questions regarding the accuracy of assertions by PacWest in public statements regarding the company's business operations and assets. PacWest,...

  20. Effect of slow rotational diffusion on angular correlations.

    NASA Technical Reports Server (NTRS)

    Marshall, A. G.; Meares, C. F.

    1972-01-01

    The theory for perturbed angular correlations of gamma radiation has been extended to include the possibility of adiabatic variation in the interaction Hamiltonian, K, for the intermediate state. The calculation begins from a polycrystalline model. It is shown that adiabatic variation in K introduces a time dependence into the angles which express the orientation of the molecular frame. The relevance of the adiabatic limit to the use of perturbed angular correlations of gamma radiation for study of the motion of radioactive species in viscous media is discussed.

  1. Evaluation of a generic RIS-PACS interface

    NASA Astrophysics Data System (ADS)

    Soehlke, Karen; Fisher, Paul D.

    1992-07-01

    An interface between a Radiology Information System (RIS) and a Picture Archiving and Communication System (PACS) has been designed in Victoria. A prototype has been developed for a Health Care Systems Inc. RIS and a Siemens PACS. The main design objective for this prototype was to create a generic RIS-PACS interface. The portability of the interface is ensured by its modularity, the utilization of a standardized language and communication protocols and the face that no changes were required to either RIS or PACS. In the case of the prototype the communication of data is unidirectional, i.e. 36 data elements are exported from RIS to PACS. Although full integration of these two information systems in the Medical Imaging department appears more desirable than interfacing, an efficient, slim RIS-PACS interface is usually the more feasibly option. Current PACS projects have to cope with the restrictions of today''s RIS and PACS, which are often not transaction-oriented, rarely use modern database models and have been designed neglecting interfacing considerations. The paper summarizes interconnection experiences of four other international projects, outlines the design of the Generic RIMS-PACS Interface and evaluates the experience with the Victoria prototype.

  2. Managed PACS operation with an automatic monitoring tool

    NASA Astrophysics Data System (ADS)

    Zhang, Jianguo; Han, Ruolin; Wu, Dongqing; Zhang, Xiaoyan; Zhuang, Jun; Feng, Jie; Wang, Mingpeng; Zhang, Guozhen; Wang, Cuanfu

    2002-05-01

    Huadong hospital in Shanghai with 800 beds provides health care services for inpatients and outpatients, as well as special senior and VIP patients. In order to move to digital imaging based radiology practice, and also provide better intra-hospital consultation services for senior and VIP patients, we started to implement PACS for hospital wide services from 1999, and also designed and developed an automatic monitoring system (AMS) to monitor and control PACS operation and dataflow to decrease the total cost of ownership for PACS operation. We installed the AMS on top of the Huadong Hospital PACS in the May of 2001. The installation was painless, did not interrupt the normal PACS operation, and took only one month. The PACS administrators with the AMS can now monitor and control the entire PACS operation in real time, and also track patient and image data flow automatically. These features make administrators take proper action even before user's complaint if any failure happened in any PACS component or process, they reduce the size of the management team, and decrease total cost of PACS ownership.

  3. Why do cost-benefit studies of PACS disagree?

    NASA Astrophysics Data System (ADS)

    van Gennip, Elisabeth M.; Ottes, Fenno P.; van Poppel, Bas M.; Andriessen, J. H. T. H.

    1990-08-01

    Once the technical difficulties of PACS have been solved, the main obstacle for its introductionwill be its costs. Even though PACS is still under development, it is clear that the equipment for PACS will be much more expensive than the equipment used in the conventional situation. PACS may, however, pay itself back by allowing savings of film, space and personnel. The conclusions of some recent cost-benefit studies disagree on the costs and benefits of PACS. Some conclude that PACS would pay for itself, whereas according to others PACS would be (much) more expensive. We analyzed the latest cost-benefit studies, to find out why their outcomes diverge. The comparison of the results revealed striking differences. The calculations of the annual costs of a hospital wide PACS varied between 2 and 4 million dollars. These differences could not be explained by differences in the size of the hospitals, as indicated by the number of examinations. They were, in part, caused by the fact that the costs per piece of equipment, material or space varied per study. For instance the costs of 1 square foot of (archive) space varied from 10 to 140 per year. The variation in the given costs of the film based system, depended on the fact whether the time spent by medical personnel on film management was taken into account. The differences among these studies demonstrate clearly the need for uniform, well-defined criteria for the calculation of the costs and savings of PACS.

  4. Recurrence of angular cheilitis.

    PubMed

    Ohman, S C; Jontell, M; Dahlen, G

    1988-08-01

    The incidence of recurrence of angular cheilitis following a successful antimicrobial treatment was studied in 48 patients. Clinical assessments including a microbial examination were carried out 8 months and 5 yr after termination of treatment. Eighty percent of the patients reported recurrence of their angular cheilitis on one or more occasions during the observation period. Patients with cutaneous disorders associated with dry skin or intraoral leukoplakia had an increased incidence of recrudescence. Neither the presence of denture stomatitis nor the type of microorganisms isolated from the original lesions of angular cheilitis, i.e. Candida albicans and/or Staphylococcus aureus, were associated with the number of recurrences. The present observations indicate that treatment of the majority of patients with angular cheilitis should be considered in a longer perspective than previously supposed, due to the short lasting therapeutic effects of the antimicrobial therapy.

  5. [Malignant angular cheilitis].

    PubMed

    Seoane, J; Vázquez, J; Cazenave, A; de la Cruz Mera, A; Argila, F; Aguado, A

    1996-01-01

    A case of chronic angular cheilitis is reported. Candida albicans was isolated repeatedly and the process developed into epitheliomatous carcinoma. The etiopathogenic role of Candida albicans and possible mechanism of action are discussed.

  6. PAC91 - PROPERTIES AND COEFFICIENTS 1991

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.

    1994-01-01

    The two principal functions of PAC91 are to provide a means of generating theoretical thermodynamic functions from molecular constant data and to supply a means of fitting these functions to empirical equations by using a least-squares fit. The coefficients obtained from the fit may then be used to generate a library of thermodynamic data in a uniform and easy-to-use format for use in other computer codes. Several large compilations of selected or calculated thermodynamic data currently exist. Nevertheless, there is a continuing need for additional calculations due to the discovery of new species, the revision of existing molecular constant data and structural parameters, the need for data at temperatures other than those already published, the availability of new or revised heats of formation, dissociation or transition, and the revision of fundamental constants or atomic weights. Calculations may also be needed to compare the results of assuming various possible forms of the partition function. In addition, there is often a preference for thermodynamic data in functional rather than tabular form. In order to satisfy these needs, the PAC91 program can perform any combination of the following: (1) calculate thermodynamic functions (heat capacity, enthalpy, entropy, and Gibbs energy) for any set of 1 to 202 temperatures, (2) obtain a least-squares fit of the first three of these functions (either individually, two at a time, or all three simultaneously) for up to eight temperature intervals, and (3) calculate, as a function of temperature, heats of formation and equilibrium constants from assigned reference elements. The thermodynamic functions for ideal gases may be calculated from molecular constant data using one of several partition function variations provided by the program. For monatomic gases, one of three partition function cutoff techniques may be selected by the user, and unobserved but predicted electronic energy levels may be included by the program

  7. PAC91 - PROPERTIES AND COEFFICIENTS 1991

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.

    1994-01-01

    The two principal functions of PAC91 are to provide a means of generating theoretical thermodynamic functions from molecular constant data and to supply a means of fitting these functions to empirical equations by using a least-squares fit. The coefficients obtained from the fit may then be used to generate a library of thermodynamic data in a uniform and easy-to-use format for use in other computer codes. Several large compilations of selected or calculated thermodynamic data currently exist. Nevertheless, there is a continuing need for additional calculations due to the discovery of new species, the revision of existing molecular constant data and structural parameters, the need for data at temperatures other than those already published, the availability of new or revised heats of formation, dissociation or transition, and the revision of fundamental constants or atomic weights. Calculations may also be needed to compare the results of assuming various possible forms of the partition function. In addition, there is often a preference for thermodynamic data in functional rather than tabular form. In order to satisfy these needs, the PAC91 program can perform any combination of the following: (1) calculate thermodynamic functions (heat capacity, enthalpy, entropy, and Gibbs energy) for any set of 1 to 202 temperatures, (2) obtain a least-squares fit of the first three of these functions (either individually, two at a time, or all three simultaneously) for up to eight temperature intervals, and (3) calculate, as a function of temperature, heats of formation and equilibrium constants from assigned reference elements. The thermodynamic functions for ideal gases may be calculated from molecular constant data using one of several partition function variations provided by the program. For monatomic gases, one of three partition function cutoff techniques may be selected by the user, and unobserved but predicted electronic energy levels may be included by the program

  8. Cosmological perturbations in unimodular gravity

    SciTech Connect

    Gao, Caixia; Brandenberger, Robert H.; Cai, Yifu; Chen, Pisin E-mail: rhb@hep.physics.mcgill.ca E-mail: chen@slac.stanford.edu

    2014-09-01

    We study cosmological perturbation theory within the framework of unimodular gravity. We show that the Lagrangian constraint on the determinant of the metric required by unimodular gravity leads to an extra constraint on the gauge freedom of the metric perturbations. Although the main equation of motion for the gravitational potential remains the same, the shift variable, which is gauge artifact in General Relativity, cannot be set to zero in unimodular gravity. This non-vanishing shift variable affects the propagation of photons throughout the cosmological evolution and therefore modifies the Sachs-Wolfe relation between the relativistic gravitational potential and the microwave temperature anisotropies. However, for adiabatic fluctuations the difference between the result in General Relativity and unimodular gravity is suppressed on large angular scales. Thus, no strong constraints on the theory can be derived.

  9. Angular velocity discrimination

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary K.

    1990-01-01

    Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

  10. Angular velocity discrimination

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary K.

    1990-01-01

    Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

  11. Random matter density perturbations and LMA

    NASA Astrophysics Data System (ADS)

    Reggiani, N.; Guzzo, M. M.; de Holanda, P. C.

    There are reasons to believe that mechanisms exist in the solar interior which lead to random density perturbations in the resonant region of the Large Mixing Angle solution to the solar neutrino problem. We find that, in the presence of these density perturbations, the best fit point in the (sin 2 2θ , Δ m2) parameter space moves to smaller values, compared with the values obtained for the standard LMA solution. Combining solar data with KamLAND results, we find a new compatibility region, which we call VERY-LOW LMA, where sin 2 2θ ~ 0.6 and Δm2 2× 10-5 eV2, for random density fluctuations of order 5% < ξ < 8%. We argue that such values of density fluctuations are still allowed by helioseismological observations at small scales of order 10 - 1000 km deep inside the solar core. PACS: 26.65 - 90.60J - 96.60.H

  12. Cosmological perturbations of quantum-mechanical origin and anisotropy of the microwave background

    NASA Technical Reports Server (NTRS)

    Grishchuk, L. P.

    1993-01-01

    Cosmological perturbations generated quantum mechanically (as a particular case, during inflation) possess statistical properties of squeezed quantum states. The power spectra of the perturbations are modulated and the angular distribution of the produced temperature fluctuations of the cosmic microwave background radiation is quite specific. An exact formula is derived for the angular correlation function of the temperature fluctuations caused by squeezed gravitational waves. The predicted angular pattern can, in principle, be revealed by observations like those by the Cosmic Background Explorer.

  13. Plasmons carrying orbital angular momentum in quantum plasmas

    NASA Astrophysics Data System (ADS)

    Khan, Shabbir A.; Ali, S.; Mendonca, J. T.; Mendonca

    2013-10-01

    The existence of plasmons with orbital angular momentum due to the Laguerre-Gaussian-type density and potential perturbations is studied in an unmagnetized quantum plasma. Starting from appropriate hydrodynamic equations for the electrostatic electron dynamics, a dispersion equation is derived in paraxial approximation. The Laguerre-Gaussian beam solutions are obtained and the properties of electric field components, energy flux, and corresponding angular momentum density of plasmons are investigated. The electric field lines are found to form helical structures with a dominant axial component. The results are analyzed numerically and the influence of radial and angular mode numbers on potential and electric field components is illustrated.

  14. PACS: implementation in the U.S. Department of Defense

    NASA Astrophysics Data System (ADS)

    Chacko, Anna K.; Wider, Ronald; Romlein, John R.; Cawthon, Michael A.; Richardson, Ronald R., Jr.; Lollar, H. William; Cook, Jay F.; Timboe, Harold L.; Johnson, Thomas G.; Fellows, Douglas W.

    2000-05-01

    The Department of Defense has been a leader in Radiology re- engineering for the past decade. Efforts have included the development of two landmark PACS specifications (MDIS and DIN- PACS), respective vendor selection and implementation programs. A Tri-Service (Army, Navy and Air Force) Radiology re-engineering program was initiated which identified transitioning to digital imaging, PACS and teleradiology as key enabling technologies in a changing business scenario. Subsequently, the systematic adjustment of procurement process for radiological imaging equipment included a focus on specifying PACS-capable-digital imaging modalities and mini- PACS as stepping stones to make the hospitals and health clinics PACS-ready. The success of the PACS and teleradiology program in the DOD is evidenced by the near filmless operation of most Army and Air Force Medical Centers, several community hospitals and several operational teleradiology constellations. Additionally, the MDIS PACSystem has become the commercial PACS product for General Electric Medical Systems. The DOD continues to forge ahead in the PACS arena by implementing advanced configurations and operational concepts such as the VRE (Virtual Radiology Environment), the negotiation of Regional Archiving and Regional PACS Maintenance Programs. Newer regulations (HIPAA, the FDA approval of digital mammography) have been promulgated impacting the culture and conduct of our business. Incorporating their requirements at the very outset will enable us to streamline the delivery of radiology. The DOD community has embraced the information age at multiple levels. The Healthcare portion of this community with these initiatives is integrating itself into DOD's future. The future holds great possibilities, promises and challenges for the DOD PACS programs.

  15. PACS component testing: beta and acceptance testing

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Frost, Meryll M.; Staab, Edward V.

    1997-05-01

    The functionality and performance expectations of all PACS components must be specified at the time of purchase and tested completely upon delivery to assure customer satisfaction and successful adoption of the new technology. This process may be more elaborate if the customer agrees to serve as a Beta test site for a new component or a new revision of an existing component.A carefully designed test plan will save time at installation, will allow the customer and vendor to agree on expectations, and will assure that the installation will proceed as planned. This paper describes the test procedure used at the University of Florida to accept each PACS component, either a commercial product, or one developed in house. A set of documents contain descriptions of the pre-installation environment, sets of studies to be used in the test, installation checklist, functional usage reports, subjective evaluations, and problem reporting forms. Training and user documentation is also reviewed and 'help lists' are created to help users perform the most common functions. Although details in the documents are changed to match the type of component being tested, the general form of the test remains the same. A formal procedure for testing the functionality and performance of new equipment can save time for both the vendor and the customer and, if specified at the time of purchase, can serve to document the expectations of the customer. Following these procedures will assure a successful installation and improve customer satisfaction.

  16. Rationale for a large facility PACS implementation

    NASA Astrophysics Data System (ADS)

    Donnelly, Joseph J.; Hindel, Peter P.; Anderson, John A.

    1992-07-01

    The Wright-Patterson USAF Medical Center (WPMC) is one of three DOD medical centers currently engaged in the installation of the ''Medical Diagnostic Imaging Support'' (MDIS) system. MDIS is a comprehensive hospital wide ''Picture Archiving and Communications System'' (PACS). In defining the requirements for the MDIS system it quickly became apparent that detailed operational information was necessary to adequately define the system requirements. This information included an understanding of the needs of our customers, workload data, current and expected future imaging capabilities, current problems encountered in meeting the needs of our customers, and the resources available to respond to these problems. Armed with this information the MDIS technical development team was able to define a detailed functional description for the MDIS system. This functional description was presented to industry in the form of a competitive solicitation with the subsequent submission of proposals by interested vendors. Following an extensive review of these proposals and the results of live benchmark evaluations, a contract was awarded to Loral Western Development Laboratory on September 27, 1991. This paper presents an operational overview of WPMC, a description of the deficiencies in our current image management system, and a discussion of the PACS to be installed this summer.

  17. Design of a full PACS with experiences of mini-PACS in Yonsei University Medical Center

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Joung; Huh, Jae-Man; Kim, Namhyun; Kim, Kee-Deog; Kim, Myoung-Jin; Kim, Sang-Jin; Yoo, Hyung-Sik

    2000-05-01

    Yonsei University Medical Center (YUMC) in Seoul, Korea is 114 years old and 1,582 beds in Shinchon Severance hospital in main university campus and 746 beds in affiliated Youngdong Severance hospital which is 20 miles away from the main campus. The dental hospital in main campus is also included in a full-PACS system. The numbers of exams/year for main, affiliated, and dental hospitals are approximately 558,000, 365,000, and 181,000, respectively. Since 1997, a Mini-PACS with 3xMRI, 2xDSI, and 2xCT in Shinchon Severance hospital has been operating to archive the digital data and to view them with DICOM viewer PiViewTM. An archiving system with 2xCT and 2xMRI in Youngdong Severance has been operating to archive the digital data. We are now designing a large-scale full-PACS for YUMC with experiences of running a mini-PACS for 3 years. The 11xUS, 7xEndoscopy, 7xCR, 3xSPECT, 1xPET, 1xCT simulator, and digital camera based patient database in the Dept. of radiation oncology in Shinchon Severance hospital will be connected to an archiving server system through modality interface gateway. The 3xCR, 2xDSA, 2xFD, 5xUS, 3xEndoscopy in Youngdong Severance hospital will be connected to the main archiving system. The 1xCT, 10xIntraoral X-ray unit DR, 4xPanoramic&cephalometric unit DR, 1xTranscranial CR, 1xScanora X-ray unit CR, 1xSectography CR in dental hospital will be connected to archiving server system through modality interface gateway. The estimated amount of data for Shinchon severance, Youngdong severance, and dental hospitals per year are 11.55TB, 5.88TB, and 0.96TB, respectively. The current mini-PACS server includes 54 GB RAID, 520 GB DLT with SUN SpectraTM server. The main server in Shinchon Severance hospital needs to be upgraded to 600GB RAID for 30 days and 10TB ODJ or DLT for the first two years. Youngdong Severance hospital needs to be installed a main server with 600GB RAID for > 30 days and 10TB ODJ or DLT for > 2 years. The interface between HIS/RIS and

  18. CMB anisotropies: Total angular momentum method

    NASA Astrophysics Data System (ADS)

    Hu, Wayne; White, Martin

    1997-07-01

    A total angular momentum representation simplifies the radiation transport problem for temperature and polarization anisotropy in the cosmic microwave background (CMB). Scattering terms couple only the quadrupole moments of the distributions and each moment corresponds directly to the observable angular pattern on the sky. We develop and employ these techniques to study the general properties of anisotropy generation from scalar, vector, and tensor perturbations to the metric and the matter, both in the cosmological fluids and from any seed perturbations (e.g., defects) that may be present. The simpler, more transparent form and derivation of the Boltzmann equations brings out the geometric and model-independent aspects of temperature and polarization anisotropy formation. Large angle scalar polarization provides a robust means to distinguish between isocurvature and adiabatic models for structure formation in principle. Vector modes have the unique property that the CMB polarization is dominated by magnetic-type parity at small angles (a factor of 6 in power compared with 0 for the scalars and 8/13 for the tensors) and hence potentially distinguishable independent of the model for the seed. The tensor modes produce a different sign from the scalars and vectors for the temperature-polarization correlations at large angles. We explore conditions under which one perturbation type may dominate over the others including a detailed treatment of the photon-baryon fluid before recombination.

  19. Angular momentum radio

    NASA Astrophysics Data System (ADS)

    Thidé, B.; Tamburini, F.; Then, H.; Someda, C. G.; Mari, Elletra; Parisi, G.; Spinello, F.; Romanato, Fra

    2014-02-01

    Wireless communication amounts to encoding information onto physical observables carried by electromagnetic (EM) fields, radiating them into surrounding space, and detecting them remotely by an appropriate sensor connected to an informationdecoding receiver. Each observable is second order in the fields and fulfills a conservation law. In present-day radio only the EM linear momentum observable is fully exploited. A fundamental physical limitation of this observable, which represents the translational degrees of freedom of the charges (typically an oscillating current along a linear antenna) and the fields, is that it is single-mode. This means that a linear-momentum radio communication link comprising one transmitting and one receiving antenna, known as a single-input-single-output (SISO) link, can provide only one transmission channel per frequency (and polarization). In contrast, angular momentum, which represents the rotational degrees of freedom, is multi-mode, allowing an angular-momentum SISO link to accommodate an arbitrary number of independent transmission channels on one and the same frequency (and polarization). We describe the physical properties of EM angular momentum and how they can be exploited, discuss real-world experiments, and outline how the capacity of angular momentum links may be further enhanced by employing multi-port techniques, i.e., the angular momentum counterpart of linear-momentum multiple-input-multiple-output (MIMO).

  20. The Angular Momentum Dichotomy

    NASA Astrophysics Data System (ADS)

    Teklu, Adelheid; Remus, Rhea-Silvia; Dolag, Klaus; Burkert, Andreas

    2015-02-01

    In the context of the formation of spiral galaxies the evolution and distribution of the angular momentum of dark matter halos have been discussed for more than 20 years, especially the idea that the specific angular momentum of the halo can be estimated from the specific angular momentum of its disk (e.g. Fall & Efstathiou (1980), Fall (1983) and Mo et al. (1998)). We use a new set of hydrodynamic cosmological simulations called Magneticum Pathfinder which allow us to split the galaxies into spheroidal and disk galaxies via the circularity parameter ɛ, as commonly used (e.g. Scannapieco et al. (2008)). Here, we focus on the dimensionless spin parameter λ = J |E|1/2 / (G M5/2) (Peebles 1969, 1971), which is a measure of the rotation of the total halo and can be fitted by a lognormal distribution, e.g. Mo et al. (1998). The spin parameter allows one to compare the relative angular momentum of halos across different masses and different times. Fig. 1 reveals a dichotomy in the distribution of λ at all redshifts when the galaxies are split into spheroids (dashed) and disk galaxies (dash-dotted). The disk galaxies preferentially live in halos with slightly larger spin parameter compared to spheroidal galaxies. Thus, we see that the λ of the whole halo reflects the morphology of its central galaxy. For more details and a larger study of the angular momentum properties of disk and spheroidal galaxies, see Teklu et al. (in prep.).

  1. Overall system design of a PACS for nuclear medicine images

    NASA Astrophysics Data System (ADS)

    Ottes, Fenno P.; Bakker, Albert R.; VanGennip, Chel; van Poppel, Bas M.; Toussaint, Pieter J.; Weber, Ruud; Weier, Onno

    1996-05-01

    This paper describes the global system design of a PACS for nuclear medicine images. This NM PACS provides facilities for image capture, storage, display, manipulation and analysis. The NM PACS workstation displays besides images also the patient data from the HIS database. The NM PACS is equipped with well-defined HIS interface, which provides interoperability with HIS systems. The system design of the NM PACS is based on: a twin client-server concept, i.e. each workstation can run a HIS client and a PACS client, each interfaced with their own server. The HIS and the PACS servers are in turn inter-connected. The PACS images can be retrieved and displayed by evoking a command to a HIS menu. The X-protocol, together with GUI tools, such as Builder Xcsessory and the Motif tools in the Xmt library, are used to create the software modules that displays, manipulates and analyzes the images. The image file storage architecture consists of a single layer, namely an array of magnetical disks.

  2. The Detector Physics and Applications Center—DePAC

    NASA Astrophysics Data System (ADS)

    Plothow-Besch, H.; Besch, H.-J.; Fiorini, C.; Grupen, C.; Hassard, J.; Longoni, A.; Walenta, A. H.

    2001-09-01

    A new project, the "Detector Physics and Applications Center (DePAC)", is presented. DePAC is a general detector and sensor database, which is not application specific, on the Internet. DePAC collects and explains the physics, the technology and the application of a wide range of radiation detectors. DePAC also collects and describes information about noise problems, front-end electronics, data transfer, processing and storage. DePAC provides short write-ups and source code of all sorts of detector related software depending on availability. DePAC collects useful constants and properties of materials in an exhaustive series of tables and graphs. DePAC also acts as a point of contact for researchers and industry in an interdisciplinary way, e.g. in biology, in medicine, in materials research and in high energy or nuclear physics. Last but not least, DePAC aims to develop also into a virtual lecturing school and serves as a tutorial for students and all interested scientists.

  3. Flagellin-PAc Fusion Protein Inhibits Progression of Established Caries.

    PubMed

    Bao, R; Yang, J Y; Sun, Y; Zhou, D H; Yang, Y; Li, Y M; Cao, Y; Xiao, Y; Li, W; Yu, J; Zhao, B L; Zhong, M H; Yan, H M

    2015-07-01

    Dental caries remains one of the most common infectious diseases of humankind, which develops slowly throughout life, affecting children, adolescents, and adults. A vaccine against caries is urgently needed. We previously developed recombinant flagellin as a mucosal adjuvant for anti-Streptococcus mutans vaccines by nasal immunization. Furthermore, we demonstrated a fusion protein strategy that combined flagellin and the target surface adhesion protein (PAc) in a single construct. This construct enhanced specific IgA responses in oral fluids and provided improved prophylactic protection against caries. In the present study, we observed prolonged progression of dental caries in rats after S. mutans Ingbritt challenge. In addition, we observed a therapeutic effect of the flagellin-PAc fusion protein (KF-rPAc) against dental caries as a mucosal vaccine with a new immunization protocol. The present study demonstrated that KF-rPAc by nasal immunization can promote PAc-specific systemic and mucosal antibody responses and inhibit dental caries progression efficiently after the implant of S. mutans into the oral cavity of the rats. The rats immunized with KF-rPAc exhibited 53.9% caries reduction compared with the sham-immunized rats. Our data support the concept of administration of KF-rPAc to humans after infection and even caries that has begun to alleviate caries progression. In conclusion, our study demonstrated that KF-rPAc could be used as an anticaries therapeutic mucosal vaccine.

  4. Building PACs: A Guide for Title I Principals.

    ERIC Educational Resources Information Center

    Druian, Janice; Sayers, Susan

    This inservice program for principals was designed to assist the development and maintenance of effective Parent Advisory Councils (PACs), as mandated by Title I of the Elementary and Secondary Education Act. The manual first introduces the concept of the principal as a facilitator, outlining the principal's role and responsibilities within a PAC.…

  5. Design and Implementation of PACS at Georgetown University Hospital

    NASA Astrophysics Data System (ADS)

    Mun, S. K.; Benson, H.. R.; Choyke, P.; Fahey, F. H.; Wang, P. C.; Zeman, R. K...; Elliott, L. P.

    1985-09-01

    During the preparation and planning phase of the PACS project at Georgetown University Hospital it was realized that PACS requires truly the state of the art technology in data communication, image processing and man machine interfacing. It was also realized that un-like many other technology intensive devices used in radiology, PACS cannot be seen as an independent system that will provide well defined services. PACS will be the backbone of the department operation in clinical, educational and managerial functions. It will indeed be the nerve center of the radiologic services affecting every aspect of the department. PACS will have to be designed to perform in a cost-effective manner to widely varying needs within the radiology departments. The integration of ever changing complex technology that will impact every aspect of a radiology service is not a trivial matter. This transition period going from current manual film based PACS to Digital PACS can be long, expansive and disruptive unless careful planning preceeds the implementation. PACS is still an emerging technology at its infancy. Performance monitoring and evaluation of diversified functions have to be also established so that improvement to the system can be efficiently implemented. Thus the evaluation criteria should be also established as early as possible.

  6. P.A.C. Training Guide = Guia de Entrenamiento.

    ERIC Educational Resources Information Center

    Colorado Migrant Education Resource Center (CoMerc), Longmont.

    Intended to give Parent Advisory Council (PAC) members exposure to their roles and responsibilities, the guide, written in Spanish and English, provides information on how to train PAC members on parliamentary procedures (Roberts Rules) and the importance of agendas and agenda construction. The guide's eight sections cover the rules/regulations,…

  7. The Logistics Of Installing Pacs In An Existing Medical Center

    NASA Astrophysics Data System (ADS)

    Saarinen, Allan O.; Goodsitt, Mitchell M.; Loop, John W.

    1989-05-01

    A largely overlooked issue in the Picture Archiving and Communication Systems (PACS) area is the tremendous amount of site planning activity required to install such a system in an existing medical center. Present PACS equipment requires significant hospital real estate, specialized electrical power, cabling, and environmental controls to operate properly. Marshaling the hospital resources necessary to install PACS equipment requires many different players. The site preparation costs are nontrivial and usually include a number of hidden expenses. This paper summarizes the experience of the University of Washington Department of Radiology in installing an extensive digital imaging network (DIN) and PACS throughout the Department and several clinics in the hospital. The major logistical problems encountered at the University are discussed, a few recommendations are made, and the installation costs are documented. Overall, the University's site preparation costs equalled about seven percent (7%) of the total PACS equipment expenditure at the site.

  8. Review Of Experience With PACS Cost Analysis Model

    NASA Astrophysics Data System (ADS)

    Cywinski, Jozef K.; Vanden Brink, John A.

    1989-05-01

    To evaluate whether the new technology of PACS can be cost justified, we have developed a computer model to analyze the costs of manual vs. digital PACS. The model was used to compute the costs of manual PACS for 14 imaging centers in 1988. The results were compared against the cost profile of an average US 400+ bed hospital derived from '85-'87 TMG PACS tracking studies in over 600 US institutions. The comparison showed that the model accurately predicted costs in these 14 imaging centers to be close to the US average. The total predicted cost per average examination was 21.49. The total annual costs were found to have a linear relationship to the number of examinations and the number of beds in the hospital. The model indicates the annual cost of a manual PACS at a 500 bed hospital to be 2 million.

  9. Fluidic angular velocity sensor

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M. (Inventor)

    1986-01-01

    A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input is described. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

  10. The angular momentum distribution in galactic halos

    NASA Astrophysics Data System (ADS)

    Quinn, P. J.; Zurek, W. H.

    1988-08-01

    N-body simulations are used to model the formation of individual galactic halos from scale-free density perturbations in universes dominated by cold, nondissipative dark matter. In well-mixed halos, the angular momentum distribution is shown to have a systematic behavior with power law index n corresponding to that found for circular rotation curves. For a given n, the distribution of angular momentum has the same trend with radius and energy as that implied for a halo in which all the matter has its maximum possible angular momentum. Dynamical mixing during the relaxation of the halo redistributes both angular momentum and binding energy in an orderly manner. The organized nature of the collapse means that relaxation is not completely violent and that the secondary infall paradigm, in its simplest form, needs to be modified to include the organizing effects of dynamical friction. It is shown that the Mestel hypothesis is not consistent with the final collapsed state of halos, but may be applicable to the collapse of the disks of spirals.

  11. Angular shear plate

    DOEpatents

    Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

    2009-07-14

    One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

  12. Optical orbital angular momentum.

    PubMed

    Barnett, Stephen M; Babiker, Mohamed; Padgett, Miles J

    2017-02-28

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next.This article is part of the themed issue 'Optical orbital angular momentum'.

  13. Optical orbital angular momentum

    PubMed Central

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-01-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069775

  14. Unveiling Angular Momentum

    NASA Astrophysics Data System (ADS)

    Robinson, Stephen

    2015-03-01

    Angular momentum is a notoriously difficult concept to grasp. Visualization often requires three-dimensional pictures of vectors pointing in seemingly arbitrary directions. A simple student-run laboratory experiment coupled with intuitive explanations by an instructor can clear up some of the inherent ambiguity of rotational motion. Specifically, the precessional period of a suspended spinning bicycle wheel can be related to the spinning frequency through a simple algebraic expression. An explanation of this precession apart from the concept of angular momentum will be given.

  15. Optical orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-02-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue 'Optical orbital angular momentum'.

  16. Effect of PAC dosage in a pilot-scale PAC-MBR treating micro-polluted surface water.

    PubMed

    Hu, Jingyi; Shang, Ran; Deng, Huiping; Heijman, Sebastiaan G J; Rietveld, Luuk C

    2014-02-01

    To address the water scarcity issue and advance the traditional drinking water treatment technique, a powdered activated carbon-amended membrane bioreactor (PAC-MBR) is proposed for micro-polluted surface water treatment. A pilot-scale study was carried out by initially dosing different amounts of PAC into the MBR. Comparative results showed that 2g/L performed the best among 0, 1, 2 and 3g/L PAC-MBR regarding organic matter and ammonia removal as well as membrane flux sustainability. 1g/L PAC-MBR exhibited a marginal improvement in pollutant removal compared to the non-PAC system. The accumulation of organic matter in the bulk mixture of 3g/L PAC-MBR led to poorer organic removal and severer membrane fouling. Molecular weight distribution of the bulk liquid in 2g/L PAC-MBR revealed the synergistic effects of PAC adsorption/biodegradation and membrane rejection on organic matter removal. Additionally, a lower amount of soluble extracellular polymer substances in the bulk can be secured in 21 days operation.

  17. Trip Report: RAM-PAC International

    SciTech Connect

    Jaques, Al; /Fermilab

    1988-09-09

    In the final design of the DO Detector, the three cryostats (CC and both EC's) will ride on a pair of hardened ways so as to move the EC's out and away from the CC cryostat to provide access between cryostats for repairs and such. Each of the cryostats sits on a carriage which has a pair of Tychoway rollers placed at each corner to roll on the hardened ways. When in position, the full weight of the cryostats is to be relieved from the rollers with the use of a pair of 90-ton jacks flanking the pair of rollers at each corner. Due to confined space, these jacks had to be custom made, triple cylinder, single block units. Five manufacturers were presented with the problem and three came back with proposals. All three satisfied the technical requirements but Ram-Pac International was easily the lowest priced.

  18. Radiologist assessment of PACS user interface devices.

    PubMed

    Weiss, David L; Siddiqui, Khan M; Scopelliti, Joe

    2006-04-01

    The process of radiologic interpretation has been revolutionized with the adoption of filmless imaging. Despite the radical change in viewing techniques and a rapidly expanding array of display, navigation, and manipulation tools, the keyboard-and-mouse configuration remains the standard for user interaction during radiologic interpretation. In this study, 6 readers evaluated 6 alternative user interface devices (UIDs), including 5-button and 8-button mice, a gyroscopic mouse, a multimedia controller, a handheld mouse-and-keyboard combination device, and a gaming joystick. Each participant assessed each device during the real-time daily imaging interpretation of magnetic resonance, computed tomographic, and general x-ray studies over a 2-week period and completed a detailed questionnaire on the ease of use, comparative utility as an alternative device to mouse and QWERTY keyboard, efficiency, workflow, and the ease of customized programming. No single device was completely able to replace the mouse and keyboard in the estimation of participants, and the 5-button mouse was preferred over the 8-button mouse, although several participants noted that this might be a function of learning curves that exceeded the 2-week study period for each device. Several specific functionalities of the alternative UIDs were praised by users, who also suggested the possibility of combining these alternative devices for 2-handed use. Consideration should be given to the potential for the increased acceptance of and efficiency with alternative UIDs that can be integrated into picture archiving and communications system (PACS) workstations. Additional studies are planned to use software applications to evaluate different UIDs at PACS workstations.

  19. "Angular" plasma cell cheilitis.

    PubMed

    da Cunha Filho, Roberto Rheingantz; Tochetto, Lucas Baldissera; Tochetto, Bruno Baldissera; de Almeida, Hiram Larangeira; Lorencette, Nádia Aparecida; Netto, José Fillus

    2014-03-17

    Plasma cell cheilitis is an extremely rare disease, characterized by erythematous-violaceous, ulcerated and asymptomatic plaques, which evolve slowly. The histological characteristics include dermal infiltrate composed of mature plasmocytes. We report a case of Plasma cell angular cheilitis in a 58-year-old male, localized in the lateral oral commissure.

  20. A UNIFIED THEORY FOR THE EFFECTS OF STELLAR PERTURBATIONS AND GALACTIC TIDES ON OORT CLOUD COMETS

    SciTech Connect

    Collins, Benjamin F.; Sari, Re'em

    2010-11-15

    We examine the effects of passing field stars on the angular momentum of a nearly radial orbit of an Oort cloud comet bound to the Sun. We derive the probability density function of the change in angular momentum from one stellar encounter, assuming a uniform and isotropic field of perturbers. We show that the total angular momentum follows a Levy flight, and determine its distribution function. If there is an asymmetry in the directional distribution of perturber velocities, the marginal probability distribution of each component of the angular momentum vector can be different. The constant torque attributed to Galactic tides arises from a non-cancellation of perturbations with an impact parameter of order the semimajor axis of the comet. When the close encounters are rare, the angular momentum is best modeled by the stochastic growth of stellar encounters. If trajectories passing between the comet and the Sun occur frequently, the angular momentum exhibits the coherent growth attributed to the Galactic tides.

  1. CMB hemispherical asymmetry from non-linear isocurvature perturbations

    SciTech Connect

    Assadullahi, Hooshyar; Wands, David; Firouzjahi, Hassan; Namjoo, Mohammad Hossein E-mail: firouz@mail.ipm.ir E-mail: david.wands@port.ac.uk

    2015-04-01

    We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear δ N formalism to calculate the non-Gaussianity of the primordial density and isocurvature perturbations due to the presence of non-adiabatic, but approximately scale-invariant field fluctuations during multi-field inflation. This local-type non-Gaussianity leads to a correlation between very long wavelength inhomogeneities, larger than our observable horizon, and smaller scale fluctuations in the radiation and matter density. Matter isocurvature perturbations contribute primarily to low CMB multipoles and hence can lead to a hemispherical asymmetry on large angular scales, with negligible asymmetry on smaller scales. In curvaton models, where the matter isocurvature perturbation is partly correlated with the primordial density perturbation, we are unable to obtain a significant asymmetry on large angular scales while respecting current observational constraints on the observed quadrupole. However in the axion model, where the matter isocurvature and primordial density perturbations are uncorrelated, we find it may be possible to obtain a significant asymmetry due to isocurvature modes on large angular scales. Such an isocurvature origin for the hemispherical asymmetry would naturally give rise to a distinctive asymmetry in the CMB polarisation on large scales.

  2. Development and implementation of a PACS network and resource manager

    NASA Astrophysics Data System (ADS)

    Stewart, Brent K.; Taira, Ricky K.; Dwyer, Samuel J., III; Huang, H. K.

    1992-07-01

    Clinical acceptance of PACS is predicated upon maximum uptime. Upon component failure, detection, diagnosis, reconfiguration and repair must occur immediately. Our current PACS network is large, heterogeneous, complex and wide-spread geographically. The overwhelming number of network devices, computers and software processes involved in a departmental or inter-institutional PACS makes development of tools for network and resource management critical. The authors have developed and implemented a comprehensive solution (PACS Network-Resource Manager) using the OSI Network Management Framework with network element agents that respond to queries and commands for network management stations. Managed resources include: communication protocol layers for Ethernet, FDDI and UltraNet; network devices; computer and operating system resources; and application, database and network services. The Network-Resource Manager is currently being used for warning, fault, security violation and configuration modification event notification. Analysis, automation and control applications have been added so that PACS resources can be dynamically reconfigured and so that users are notified when active involvement is required. Custom data and error logging have been implemented that allow statistics for each PACS subsystem to be charted for performance data. The Network-Resource Manager allows our departmental PACS system to be monitored continuously and thoroughly, with a minimal amount of personal involvement and time.

  3. Boundary perturbation theory for nonanalytic perturbations

    SciTech Connect

    Pomraning, G.C.

    1983-10-01

    First-order perturbation formulas are derived that give the change in the eigenvalue of a reactive system due to a perturbation in the exterior shape of the system. In physical terms, this perturbation involves adding a thin layer of arbitrary material to the surface of the unperturbed system (or deleting material past a material discontinuity). From a mathematical viewpoint, the perturbation is sufficiently general to give rise to a nonanalytic behavior of the eigenvalue on the smallness parameter. Both transport theory and the diffusion approximation are treated.

  4. Angular diameter distances reconsidered in the Newman and Penrose formalism

    NASA Astrophysics Data System (ADS)

    Kling, Thomas P.; Aly, Aly

    2016-02-01

    Using the Newman and Penrose spin coefficient (NP) formalism, we provide a derivation of the Dyer-Roeder equation for the angular diameter distance in cosmological space-times. We show that the geodesic deviation equation written in NP formalism is precisely the Dyer-Roeder equation for a general Friedman-Robertson-Walker (FRW) space-time, and then we examine the angular diameter distance to redshift relation in the case that a flat FRW metric is perturbed by a gravitational potential. We examine the perturbation in the case that the gravitational potential exhibits the properties of a thin gravitational lens, demonstrating how the weak lensing shear and convergence act as source terms for the perturbed Dyer-Roeder equation.

  5. PacCYP707A2 negatively regulates cherry fruit ripening while PacCYP707A1 mediates drought tolerance.

    PubMed

    Li, Qian; Chen, Pei; Dai, Shengjie; Sun, Yufei; Yuan, Bing; Kai, Wenbin; Pei, Yuelin; He, Suihuan; Liang, Bin; Zhang, Yushu; Leng, Ping

    2015-07-01

    Sweet cherry is a non-climacteric fruit and its ripening is regulated by abscisic acid (ABA) during fruit development. In this study, four cDNAs (PacCYP707A1-4) encoding 8'-hydroxylase, a key enzyme in the oxidative catabolism of ABA, were identified in sweet cherry fruits using tobacco rattle virus-induced gene silencing (VIGS) and particle bombardment approaches. Quantitative real-time PCR confirmed significant down-regulation of target gene transcripts in VIGS-treated cherry fruits. In PacCYP707A2-RNAi-treated fruits, ripening and fruit colouring were promoted relative to control fruits, and both ABA accumulation and PacNCED1 transcript levels were up-regulated by 140%. Silencing of PacCYP707A2 by VIGS significantly altered the transcripts of both ABA-responsive and ripening-related genes, including the ABA metabolism-associated genes NCED and CYP707A, the anthocyanin synthesis genes PacCHS, PacCHI, PacF3H, PacDFR, PacANS, and PacUFGT, the ethylene biosynthesis gene PacACO1, and the transcription factor PacMYBA. The promoter of PacMYBA responded more strongly to PacCYP707A2-RNAi-treated fruits than to PacCYP707A1-RNAi-treated fruits. By contrast, silencing of PacCYP707A1 stimulated a slight increase in fruit colouring and enhanced resistance to dehydration stress compared with control fruits. These results suggest that PacCYP707A2 is a key regulator of ABA catabolism that functions as a negative regulator of fruit ripening, while PacCYP707A1 regulates ABA content in response to dehydration during fruit development. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Architectural decisions with respect to the introduction of PACS.

    PubMed

    Lodder, H; Kalshoven, M; Toussaint, P; Zwetsloot-Schonk, B

    2002-01-01

    In this paper we report on a study on the possible scenarios for the introduction of PACS that was conducted at the LUMC in 2002 by a workgroup. The results of this study should facilitate the decision on PACS to be taken by the management of the LUMC at a later stage. In this paper our main research question is to what extent the decisions to be made at the introduction of PACS can be derived from an information system architecture in place, and vice versa: how can these decisions help to refine an information system architecture that is still immature.

  7. A Herschel PACS and SPIRE study of the dust content of the Cassiopeia A supernova remnant

    NASA Astrophysics Data System (ADS)

    Barlow, M. J.; Krause, O.; Swinyard, B. M.; Sibthorpe, B.; Besel, M.-A.; Wesson, R.; Ivison, R. J.; Dunne, L.; Gear, W. K.; Gomez, H. L.; Hargrave, P. C.; Henning, Th.; Leeks, S. J.; Lim, T. L.; Olofsson, G.; Polehampton, E. T.

    2010-07-01

    Using the 3.5-m Herschel Space Observatory, imaging photometry of Cas A has been obtained in six bands between 70 and 500 μm with the PACS and SPIRE instruments, with angular resolutions ranging from 6 to 37”. In the outer regions of the remnant the 70-μm PACS image resembles the 24-μm image Spitzer image, with the emission attributed to the same warm dust component, located in the reverse shock region. At longer wavelengths, the three SPIRE bands are increasingly dominated by emission from cold interstellar dust knots and filaments, particularly across the central, western and southern parts of the remnant. Nonthermal emission from the northern part of the remnant becomes prominent at 500 μm. We have estimated and subtracted the contributions from the nonthermal, warm dust and cold interstellar dust components. We confirm and resolve for the first time a cool (~35 K) dust component, emitting at 70-160 μm, that is located interior to the reverse shock region, with an estimated mass of 0.075 M_⊙. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Figure 3 is only available in electronic form at http://www.aanda.org

  8. Bacteriophage SPP1 pac Cleavage: A Precise Cut without Sequence Specificity Requirement.

    PubMed

    Djacem, Karima; Tavares, Paulo; Oliveira, Leonor

    2017-01-09

    In many tailed bacteriophages, DNA packaging is initiated by recognition and cleavage of a specific sequence pac by the small (TerS) and large (TerL) terminase subunits. It was previously shown that the SPP1 pac region has two sequences where TerS binds (pacR and pacL), flanking the segment where TerL cleaves the SPP1 DNA (pacC). However, the pac-specific sequences required to achieve this endonucleolytic cut were not established. Their characterization is essential to understand the underlying mechanism. We show that the pacR sequence localized within 35bp downstream of the pac cut can be extensively degenerated, including its c1 and c2 repeats, and that only a disruption of a 5-bp polyadenine tract impairs the pac cleavage. This result together with deletion analysis of pacL shows that the specific DNA sequences required for targeting the terminase for pac cleavage are considerably shorter than the large region bound by TerS. Furthermore, extensive degeneration of the 6-bp target sequence within pacC where pac cleavage occurs reveals that TerL maintains, remarkably, its precise position of cleavage. Studies with SPP1-related phages show the conservation of the cut position, irrespective of the sequence variation in pacC and in pacR or the changes in pacL-pacC distance. Mechanistically, our data are compatible with a model in which TerS interactions with part of the pacL sequence and a poly-A tract in pacR are sufficient to orient very accurately the TerL nuclease to a defined pacC position. They also demonstrate that the resulting precise cut at pacC is independent of the targeted DNA sequence.

  9. Disaster-hardened imaging POD for PACS

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice; Frost, Meryll

    2005-04-01

    operated on emergency power, a limited, but effective number of studies could be performed. However, in a digital department, there is a reliance on the network infrastructure to deliver images to viewing locations. The system developed for our institution uses several imaging PODS, a name we chose because it implied to us a safe, contained environment. Each POD is on both the standard and the emergency power systems. All the vendor equipment that produces images is on a private, stand-alone network controlled either by a simple or a managed switch. Included in each POD is a dry-process DICOM printer that is rarely used during normal operations and a display workstation. One node on the private network is a PACS application processor (AP) with two network interface cards, one for the private network, one for the standard PACS network. During ordinary daily operations, all acquired images pass through this AP and are routed to the PACS archives, web servers, and workstations. However, if the power and network to much of the hospital were to fail, the stand-alone POD could still function. Images are routed to the AP, but cannot forward to the main network. However, they can be routed to the printer and display in the POD. They are also stored on the AP to continue normal routing when the infrastructure is restored. Results: The imaging PODS have been tested in actual disaster testing where the infrastructure was intentionally removed and worked as designed. To date, we have not had to use them in a real-life scenario and we hope we never do, but we feel we have a reasonable level of emergency imaging capability if we ever need it. Conclusions: Our testing indicates our PODS are a viable way to continue medical imaging in the face of an emergency with a major part of our network and electrical infrastructure destroyed.

  10. Quantum Heuristics of Angular Momentum

    ERIC Educational Resources Information Center

    Levy-Leblond, Jean-Marc

    1976-01-01

    Discusses the quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus, without using operators or commutation relations. (MLH)

  11. Angular cheilitis after tonsillectomy.

    PubMed

    England, R J; Lau, M; Ell, S R

    1999-08-01

    The operation of tonsillectomy requires the oral cavity to be held open mechanically in an unconscious patient, and intra-oral instrumentation to occur. Angular cheilitis may arise as a result of this after operation. This can cause morbidity and delay the re-establishment of a normal diet. The aim of this study was to identify what factors increase the likelihood of developing this problem postoperatively. Sixty patients were randomly selected in a prospective manner. Preoperative, intraoperative and postoperative variables were recorded. The frequency of development of postoperative angular cheilitis was recorded. The prevalence of the condition was related to the prerecorded variables. Parametric analysis showed that the chance of developing angular cheilitis was directly related to the use of diathermy haemostasis (P = 0.05). Logistic regression analysis showed that the odds ratio of developing this complication if diathermy was used is 3.5 (95% confidence intervals 0.99, 12.4) and operation difficulty may also be a relevant variable. No other recorded variables were found to be significant.

  12. Picture Archiving And Communication Systems (PACS): Introductory Systems Analysis Considerations

    NASA Astrophysics Data System (ADS)

    Hughes, Simon H. C.

    1983-05-01

    Two fundamental problems face any hospital or radiology department that is thinking about installing a Picture Archiving and Communications System (PACS). First, though the need for PACS already exists, much of the relevant technology is just beginning to be developed. Second, the requirements of each hospital are different, so that any attempts to market a single PACS design for use in large numbers of hospitals are likely to meet with the same problems as were experienced with general-purpose Hospital Information Systems. This paper outlines some of the decision processes involved in arriving at specifications for each module of a PACS and indicates design principles which should be followed in order to meet individual hospital requirements, while avoiding the danger of short-term systems obsolescence.

  13. PACS archive upgrade and data migration: clinical experiences

    NASA Astrophysics Data System (ADS)

    Liu, Brent J.; Documet, Luis; Sarti, Dennis A.; Huang, H. K.; Donnelly, John

    2002-05-01

    Saint John's Health Center PACS data volumes have increased dramatically since the hospital became filmless in April of 1999. This is due in part of continuous image accumulation, and the integration of a new multi-slice detector CT scanner into PACS. The original PACS archive would not be able to handle the distribution and archiving load and capacity in the near future. Furthermore, there is no secondary copy backup of all the archived PACS image data for disaster recovery purposes. The purpose of this paper is to present a clinical and technical process template to upgrade and expand the PACS archive, migrate existing PACs image data to the new archive, and provide a back-up and disaster recovery function not currently available. Discussion of the technical and clinical pitfalls and challenges involved in this process will be presented as well. The server hardware configuration was upgraded and a secondary backup implemented for disaster recovery. The upgrade includes new software versions, database reconfiguration, and installation of a new tape jukebox to replace the current MOD jukebox. Upon completion, all PACS image data from the original MOD jukebox was migrated to the new tape jukebox and verified. The migration was performed during clinical operation continuously in the background. Once the data migration was completed the MOD jukebox was removed. All newly acquired PACS exams are now archived to the new tape jukebox. All PACs image data residing on the original MOD jukebox have been successfully migrated into the new archive. In addition, a secondary backup of all PACS image data has been implemented for disaster recovery and has been verified using disaster scenario testing. No PACS image data was lost during the entire process and there was very little clinical impact during the entire upgrade and data migration. Some of the pitfalls and challenges during this upgrade process included hardware reconfiguration for the original archive server, clinical

  14. On stochastic approximation algorithms for classes of PAC learning problems

    SciTech Connect

    Rao, N.S.V.; Uppuluri, V.R.R.; Oblow, E.M.

    1994-03-01

    The classical stochastic approximation methods are shown to yield algorithms to solve several formulations of the PAC learning problem defined on the domain [o,1]{sup d}. Under some assumptions on different ability of the probability measure functions, simple algorithms to solve some PAC learning problems are proposed based on networks of non-polynomial units (e.g. artificial neural networks). Conditions on the sizes of these samples required to ensure the error bounds are derived using martingale inequalities.

  15. Architecture for a PACS primary diagnosis workstation

    NASA Astrophysics Data System (ADS)

    Shastri, Kaushal; Moran, Byron

    1990-08-01

    A major factor in determining the overall utility of a medical Picture Archiving and Communications (PACS) system is the functionality of the diagnostic workstation. Meyer-Ebrecht and Wendler [1] have proposed a modular picture computer architecture with high throughput and Perry et.al [2] have defined performance requirements for radiology workstations. In order to be clinically useful, a primary diagnosis workstation must not only provide functions of current viewing systems (e.g. mechanical alternators [3,4]) such as acceptable image quality, simultaneous viewing of multiple images, and rapid switching of image banks; but must also provide a diagnostic advantage over the current systems. This includes window-level functions on any image, simultaneous display of multi-modality images, rapid image manipulation, image processing, dynamic image display (cine), electronic image archival, hardcopy generation, image acquisition, network support, and an easy user interface. Implementation of such a workstation requires an underlying hardware architecture which provides high speed image transfer channels, local storage facilities, and image processing functions. This paper describes the hardware architecture of the Siemens Diagnostic Reporting Console (DRC) which meets these requirements.

  16. Transient effects in Herschel/PACS spectroscopy

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Jacobson, Jeffery D.; Appleton, Philip N.

    2016-10-01

    Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident flux with a certain delay. This generates transient effects on the resulting signal which can be important and last for up to an hour. Aims: The paper presents a study of the effects of transients on the detected signal and proposes methods to mitigate them especially in the case of the unchopped mode. Methods: Since transients can arise from a variety of causes, we classified them in three main categories: transients caused by sudden variations of the continuum due to the observational mode used; transients caused by cosmic ray impacts on the detectors; transients caused by a continuous smooth variation of the continuum during a wavelength scan. We propose a method to disentangle these effects and treat them separately. In particular, we show that a linear combination of three exponential functions is needed to fit the response variation of the detectors during a transient. An algorithm to detect, fit, and correct transient effects is presented. Results: The solution proposed to correct the signal for the effects of transients substantially improves the quality of the final reduction with respect to the standard methods used for archival reduction in the cases where transient effects are most pronounced. Conclusions: The programs developed to implement the corrections are offered through two new interactive data reduction pipelines in the latest releases of the Herschel Interactive Processing Environment.

  17. PACS-based model for telemedicine

    NASA Astrophysics Data System (ADS)

    Bastos de Figueiredo, Julio C.; Furuie, Sergio S.; Gutierrez, Marco A.; Melo, Candido P.

    2001-08-01

    In this work we present a practical model of telemedicine usage based on a HIS/PACS system that was developed and is being tested at the Heart Institute of Sao Paulo, Brazil). The objective of this project is to allow hospitals that are distant of specialized medical centers to have access to the services of other medical institutions using a low cost telemedicine solution supported by an appropriate architecture of storage and management of medical information. The services that can be accessed using this solution are, for example, second medical opinion, medical images databases and reports of clinical exams. With a simple architecture and easy operation, this project showed to be an efficient way to make a bridge between modern medicine centers and others, localized in places not provided by specialized medical assistance. The system described is still a prototype in experimental phase operating at the Heart Institute of Sao Paulo with good results and will shortly equip other hospitals (auxiliary units of the Heart Institute).

  18. Early Experience In Interfacing PACS To RIS

    NASA Astrophysics Data System (ADS)

    Boehme, Johannes M.; Choplin, Robert H.; Maynard, C. D.

    1989-05-01

    Picture Archiving and Communications Systems are sophisticated computer systems designed to store and display medical images. It has been suggested that these systems may be more cost effective than film in practicing radiology because of better access to images by multiple users, better integration of information from multiple studies, and more rapid delivery of diagnostic reports to clinical physicians. Development of these systems is in its early stages and questions have arisen as to what functions an image management system should have and how it should interact with stand alone radiology information systems (RIS) and hospital information systems (HIS). Over the past decade, computer systems have undergone gradual reorganization from highly centralized hospital (or medical center) information systems toward decentralized departmental systems. The former systems often provided global functions but did not have the flexibility to meet the needs of individual departments. Some individual departmental systems were developed to meet specific requirements, but they were often unable to communicate with other systems within a medical center. Today many RIS's have the ability to provide departmental management tools, as well as to communicate with external systems. In order to achieve a filmless environment, PACS and HIS must be integrated with RIS systems to provide the level of information currently available. An additional goal of these systems is to automate operations and reduce the workload for technologists, admission personnel, file room staff, and radiologists.

  19. Children's hospitals and PACS: six profiles of planning and implementation.

    PubMed

    Keen, C

    1999-01-01

    Six pediatric hospitals were interviewed at length about the status of PACS in their facilities. Children's Hospital Medical Center in Cincinnati, Ohio entered electronic imaging communications in 1993. Several nearby clinics were connected through teleradiology and by 1998, the radiology department had developed a business plan for the implementation of PACS. Two hospitals in Atlanta, Egleston Hospital and Scottish Rite Children's. Medical Center, merged in 1998 to become one entity with two medical campuses. They now treat 60 percent of Atlanta's pediatric patients. Merging incompatible systems has been the administrator's most immediate problem. One director of imaging services is responsible for the recently merged Mary Bridge Children's Hospital and Tacoma General Hospital, plus a network of clinics and medical facilities scatted throughout Tacoma and the South Puget Sound area in Washington state. A state-of-the-art mini-PACS and teleradiology system were implemented at Primary Children's Medical Center, Salt Lake City, in 1991. Over the years, it has added modalities into an electronic system that now results in significantly improved use of physicians' time and patient relations. St. Louis Children's Hospital, with both a director of radiology and a PACS administrator, has implemented teleradiology and an ultrasound mini-PACS, and has plans for an enterprise-wide PACS. Children's Hospital in Birmingham, Ala., a major trauma center, provides specialized pediatric care to nearly all 67 counties in Alabama. With a 20-year history of online computerization, it is now reengineering its emergency department and will implement CR there first.

  20. Envelope Modes of Beams with Angular Momentum

    SciTech Connect

    Barnard, J J; Losic, B

    2000-08-21

    For a particle beam propagating in an alternating gradient focusing system, envelope equations are often employed to describe the evolution of the beam radii in the two directions transverse to the direction of propagation, and aligned with the principle axes of the alternating gradient system. When the beams have zero net angular momentum and when the alternating gradient focusing is approximated by a continuous focusing system, there are two normal modes to the envelope equations: the 'breathing' mode and a 'quadrupole' mode. In the former, the two radii oscillate in phase, and in the latter the radii oscillate 180 degrees out of phase. In this paper, we extend the analysis to include beams that have a finite angular momentum. We perturb the moment equations of ref. [1], wherein it was assumed that space charge is a distributed in a uniform density ellipse. Two additional modes are obtained. The breathing mode remains, but the quadrupole mode is split into two modes, and a new low frequency mode appears. We calculate the frequencies and eigenmodes of these four modes as a function of tune depression and a dimensionless net angular momentum. These modes can be excited by rotational errors of the quadrupoles in an alternating gradient focusing channel.

  1. Angular Momentum in Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Del Popolo, A.

    We study the ``angular momentum catastrophe" in the framework of interaction among baryons and dark matter through dynamical friction. By means of Del Popolo (2009) model we simulate 14 galaxies similar to those investigated by van den Bosch, Burkert and Swaters (2001), and calculate the distribution of their spin parameters and the angular momenta. Our model gives the angular momentum distribution which is in agreement with the van den Bosch et al. observations. Our result shows that the ``angular momentum catastrophe" can be naturally solved in a model that takes into account the baryonic physics and the exchange of energy and angular momentum between the baryonic clumps and dark matter through dynamical friction.

  2. Optical angular momentum and atoms.

    PubMed

    Franke-Arnold, Sonja

    2017-02-28

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors.This article is part of the themed issue 'Optical orbital angular momentum'.

  3. Optical angular momentum and atoms

    NASA Astrophysics Data System (ADS)

    Franke-Arnold, Sonja

    2017-02-01

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue 'Optical orbital angular momentum'.

  4. Angular distributions in multifragmentation

    SciTech Connect

    Stoenner, R.W.; Klobuchar, R.L.; Haustein, P.E.; Virtes, G.J.; Cumming, J.B.; Loveland, W.

    2006-04-15

    Angular distributions are reported for {sup 37}Ar and {sup 127}Xe from 381-GeV {sup 28}Si+Au interactions and for products between {sup 24}Na and {sup 149}Gd from 28-GeV {sup 1}H+Au. Sideward peaking and forward deficits for multifragmentation products are significantly enhanced for heavy ions compared with protons. Projectile kinetic energy does not appear to be a satisfactory scaling variable. The data are discussed in terms of a kinetic-focusing model in which sideward peaking is due to transverse motion of the excited product from the initial projectile-target interaction.

  5. Angular Asteroid Composite

    NASA Image and Video Library

    2017-02-10

    This composite of 25 images of asteroid 2017 BQ6 was generated with radar data collected using NASA's Goldstone Solar System Radar in California's Mojave Desert. The images were gathered on Feb. 7, 2017, between 8:39 and 9:50 p.m. PST (11:39 p.m. EST and 12:50 a.m., Feb. 7), revealing an irregular, angular-appearing asteroid about 660 feet (200 meters) in size that rotates about once every three hours. The images have resolutions as fine as 12 feet (3.75 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21452

  6. Effect of powdered activated carbon (PAC) on MBR performance and effluent trihalomethane formation: At the initial stage of PAC addition.

    PubMed

    Gao, Yue; Ma, Defang; Yue, Qinyan; Gao, Baoyu; Huang, Xia

    2016-09-01

    In this study, the MBR was used to treat municipal wastewater for reuse. Effects of powdered activated carbon (PAC) addition on MBR system in terms of effluent water quality, trihalomethane (THM) formation and membrane organic fouling tendency of MBR sludge supernatant at the initial stage of PAC addition were investigated. Effects of chlorine dose and contact time on THM formation and speciation were also studied. PAC addition enhanced the removal of organic matters, especially aromatic components, which improved the UV254 removal rate from 34% to 83%. PAC addition greatly reduced the membrane organic fouling tendency of MBR sludge supernatant. PAC addition reduced the MBR effluent trihalomethane formation potential (THMFP) from 351.29 to 241.95μg/L, while increased THM formation reactivity by 42%. PAC addition enhanced the formation of higher toxic bromine-containing THMs. High chlorine dose and contact time resulted in higher THM formation but lower proportion of bromine-containing THMs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Fault tolerant high-performance PACS network design and implementation

    NASA Astrophysics Data System (ADS)

    Chimiak, William J.; Boehme, Johannes M.

    1998-07-01

    The Wake Forest University School of Medicine and the Wake Forest University/Baptist Medical Center (WFUBMC) are implementing a second generation PACS. The first generation PACS provided helpful information about the functional and temporal requirements of the system. It highlighted the importance of image retrieval speed, system availability, RIS/HIS integration, the ability to rapidly view images on any PACS workstation, network bandwidth, equipment redundancy, and the ability for the system to evolve using standards-based components. This paper deals with the network design and implementation of the PACS. The physical layout of the hospital areas served by the PACS, the choice of network equipment and installation issues encountered are addressed. Efforts to optimize fault tolerance are discussed. The PACS network is a gigabit, mixed-media network based on LAN emulation over ATM (LANE) with a rapid migration from LANE to Multiple Protocols Over ATM (MPOA) planned. Two fault-tolerant backbone ATM switches serve to distribute network accesses with two load-balancing 622 megabit per second (Mbps) OC-12 interconnections. The switch was sized to be upgradable to provide a 2.54 Gbps OC-48 interconnection with an OC-12 interconnection as a load-balancing backup. Modalities connect with legacy network interface cards to a switched-ethernet device. This device has two 155 Mbps OC-3 load-balancing uplinks to each of the backbone ATM switches of the PACS. This provides a fault-tolerant logical connection to the modality servers which pass verified DICOM images to the PACS servers and proper PACS diagnostic workstations. Where fiber pulls were prohibitively expensive, edge ATM switches were installed with an OC-12 uplink to a backbone ATM switches. The PACS and data base servers are fault-tolerant, hot-swappable Sun Enterprise Servers with an OC-12 connection to a backbone ATM switch and a fast-ethernet connection to a back-up network. The workstations come with 10

  8. Learn from experience: insights of 200+ PACS customers.

    PubMed

    Swaton, Norm

    2002-01-01

    This article is based on a PACS study published in June 2001 by KLAS Enterprises. The study offers unique insight into the performance, underlying technology, product depth and breadth, and "real world" issues facing 10 of the leading PACS vendors and their clients as rated at more than 200 of their client sites by CIOs, department directors and vendor executives. The driving force behind this report reflects the heightened interest in PACS systems in general and PACS' contributions to the benefits associated with an electronic medical record. This research was sponsored by 10 healthcare provider organizations (not vendors), ranging from a 150-bed acute-care hospital to a seven-hospital IDN. Most of the data in the report focuses on the use of PACS in the radiology department, since comparatively few sites are using PACS systems in other departments, such as cardiology or pathology. The participating vendors supplied their customer lists, which contributed to the majority of clients surveyed. Clients surveyed in the study vary widely in size, ranging from 50 to 2,000 beds, with about 46 percent of those surveyed having a hospital size of more than 400 beds. The customers represent a broad cross-section of PACS clients, ranging from 10 percent to 95 percent filmless, with large-scale users making up the majority of respondents. Each of the customers were asked to numerically rate their vendor on 28 aspects of performance, as well as to answer 12 questions relating to customer satisfaction. Based on study results, success with PACS can be distilled into some basic principles. There are other issues that will help with a successful PACS selection and implementation, but the following list should help anyone get started. If you are able to focus on and accomplish these few things, you stand a better chance of building and meeting your business case. Pre-sell your PACS concept to the radiologists, technicians, IS/IT staff supporting it and to the referring physicians

  9. [Construction of controlled expression system of class B G-protein coupled receptor PAC1].

    PubMed

    Li, Mei; Yu, Rongjie; Zhong, Jiaping; Cui, Zekai; Yang, Yanxu; Zhang, Huahua

    2014-04-01

    PAC1 is the neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) preferring receptor, which belongs to class B G protein-coupled receptors (GPCR) family. PAC1 mediates the most effects of PACAP as neurotransmitter, neuroregulator and neuroprotectant, while its high expression has close relationship with some physiological and pathological processes such as nerve-injury and tumor. To further understand the function of PAC1, a cell line that expressed inducible PAC1 was constructed to achieve Doxycycline (Dox) dependent expression of PAC1 in CHO (Chinese hamster ovary) cell using the improved Tet (tetracycline)-on Advanced System. First, the PAC1-EYFP fusion gene composed of PAC1 gene and gene encoding EYFP (enhanced yellow fluorescent protein) was sub-cloned to the tetracycline response element pTRE-Tight vector to construct the recombinant vector pEYFP-PAC1-EYFP by double enzyme digestion. Second, the tetracycline regulation components pTet-On advanced vector and the response element pTRE-PAC1-EYFP vector were both introduced into CHO cells successively and the positive clones were screened with G418 and hygromycin respectively. Third, the controlled expression of PAC1-EYFP in CHO was induced by tetracycline analogues Dox in different concentrations and the different levels of receptor PAC1-EYFP were detected. The results of fluorescence analysis and western blotting show that the cell strain with Dox dependent expression of PAC1-EYFP named PAC1-Tet-CHO was obtained. Moreover, in PAC1-Tet-CHO cells the expression of PAC1-EYFP was induced by Dox in a dose-dependent manner. The inducible expression of PAC1 still was stable after sub-culturing for more than 10 passages. It was also found by MTT assay that the higher expression level of PAC1 endowed the cells with higher proliferative viabilities. The construction of controlled expression system of PAC1 will lay a foundation for the further research on PAC1 profiles.

  10. Cardio-PACs: a new opportunity

    NASA Astrophysics Data System (ADS)

    Heupler, Frederick A., Jr.; Thomas, James D.; Blume, Hartwig R.; Cecil, Robert A.; Heisler, Mary

    2000-05-01

    It is now possible to replace film-based image management in the cardiac catheterization laboratory with a Cardiology Picture Archiving and Communication System (Cardio-PACS) based on digital imaging technology. The first step in the conversion process is installation of a digital image acquisition system that is capable of generating high-quality DICOM-compatible images. The next three steps, which are the subject of this presentation, involve image display, distribution, and storage. Clinical requirements and associated cost considerations for these three steps are listed below: Image display: (1) Image quality equal to film, with DICOM format, lossless compression, image processing, desktop PC-based with color monitor, and physician-friendly imaging software; (2) Performance specifications include: acquire 30 frames/sec; replay 15 frames/sec; access to file server 5 seconds, and to archive 5 minutes; (3) Compatibility of image file, transmission, and processing formats; (4) Image manipulation: brightness, contrast, gray scale, zoom, biplane display, and quantification; (5) User-friendly control of image review. Image distribution: (1) Standard IP-based network between cardiac catheterization laboratories, file server, long-term archive, review stations, and remote sites; (2) Non-proprietary formats; (3) Bidirectional distribution. Image storage: (1) CD-ROM vs disk vs tape; (2) Verification of data integrity; (3) User-designated storage capacity for catheterization laboratory, file server, long-term archive. Costs: (1) Image acquisition equipment, file server, long-term archive; (2) Network infrastructure; (3) Review stations and software; (4) Maintenance and administration; (5) Future upgrades and expansion; (6) Personnel.

  11. Orbital angular momentum entanglement

    NASA Astrophysics Data System (ADS)

    Romero, Mary Jacquiline Romero

    Entanglement in higher dimensions is an attractive concept that is a challenge to realise experimentally. To this end, the entanglement of the orbital angular momentum (OAM) of photons holds promise. The OAM state-space is discrete and theoretically unbounded. In the work that follows, we investigate various aspects of OAM entanglement. We show how the correlations in OAM and its conjugate variable, angular position, are determined by phase- matching and the shape of the pump beam in spontaneous parametric down- conversion. We implement tests of quantum mechanics which have been previously done for other variables. We show the Einstein-Podolsky-Rosen paradox for OAM and angle, supporting the incompatibility of quantum mechanics with locality and realism. We demonstrate violations of Bell-type inequalities, thereby discounting local hidden variables for describing the correlations we observe. We show the Hardy paradox using OAM, again highlighting the nonlocal nature of quantum mechanics. We demonstrate violations of Leggett-type inequalities, thereby discounting nonlocal hidden variables for describing correlations. Lastly, we have looked into the entanglement of topological vortex structures formed from a special superposition of OAM modes and show violations of Bell-type inequalities confined to a finite, isolated volume.

  12. Angular displacement measuring device

    NASA Technical Reports Server (NTRS)

    Seegmiller, H. Lee B. (Inventor)

    1992-01-01

    A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

  13. Angular displacement measuring device

    NASA Astrophysics Data System (ADS)

    Seegmiller, H. Lee B.

    1992-08-01

    A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

  14. Traffic between PACS and HIS/RIS: data or information?

    NASA Astrophysics Data System (ADS)

    Bakker, Albert R.; Lodder, Herman; Kouwenberg, Jef M.

    1990-08-01

    When studying the functions to be supplied by a PACS the need for a link with the HIS/RIS turns out to necessary for two classes of reasons: - the first class deals with the need to supply as much clinical information at the workstations as possible. Whether this information is stored within the HIS/RIS should be transparant to the user. - modelling and simulation of PACS gives evidence that thetraffic load in a PACS can only be handled adequately when the image management system can take into account patient flow and patient medical story. As typical example can be mentioned prefetching algorithms that take care of activation of images from the archive before they are actually needed. The activation process is controlled by events in the hospital that indicate an increased probability that these images will be needed. The first class of reasons lead in general only to use of data that in principle can just be presented on the screen of the workstation. The PACS does not need to be aware of the meaning of the data: no common understanding is necessary. So just data can be transfered that will be presented in a transparant way. The second class of reasons deals with data from the HIS/RIS that should be understood by the PACS to be able to take the required action. So the meaning of the data is to be known. In this second class we have to deal with exchange of information while for the first class exchange just data is sufficient. Since the concepts of PACS and HIS are to a large extent similar it is not evident to which of the two certain functions will be assigned. This assignment of functions is considered and some suggestions for implementation of a link between PACS and HIS/RIS are given.

  15. Density perturbation theory

    SciTech Connect

    Palenik, Mark C.; Dunlap, Brett I.

    2015-07-28

    Despite the fundamental importance of electron density in density functional theory, perturbations are still usually dealt with using Hartree-Fock-like orbital equations known as coupled-perturbed Kohn-Sham (CPKS). As an alternative, we develop a perturbation theory that solves for the perturbed density directly, removing the need for CPKS. This replaces CPKS with a true Hohenberg-Kohn density perturbation theory. In CPKS, the perturbed density is found in the basis of products of occupied and virtual orbitals, which becomes ever more over-complete as the size of the orbital basis set increases. In our method, the perturbation to the density is expanded in terms of a series of density basis functions and found directly. It is possible to solve for the density in such a way that it makes the total energy stationary even if the density basis is incomplete.

  16. OT1_rpaladin_1: PACS and SPIRE observations of Galactic anomalous emission sources.

    NASA Astrophysics Data System (ADS)

    Paladini, R.

    2010-07-01

    Despite the increasing evidence that the anomalous emission is a new physical mechanism acting in the diffuse interstellar medium, the nature and distribution of this component remains elusive. The currently most favored models attribute the observed microwave excess to rotating very small dust grains (PAHs and VSGs). Nonetheless, the infrared properties of the sources which, to date, are known to exhibit this type of emission are very poorly known mostly due to the limited angular resolution and frequency coverage of DIRBE and IRAS data. We propose HERSCHEL PACS and SPIRE mapping of three Galactic anomalous emission sources (LDN 1780, LDN 675 and LDN 1111). This data, when combined with ancillary NIR and mid-IR data of comparable angular resolution (mainly from Spitzer), and coupled with available dust models, will allow to set tight constraints on the radiation field in the emitting sources as well as in their immediate surroundings. Such constraints, in turn, will allow to estimate the abundances of PAHs, VSGs and BGs, hence to shed light on the potential link between these dust populations and the observed microwave excess.

  17. Non-Gaussianities in DBI inflation with angular motion

    NASA Astrophysics Data System (ADS)

    Kidani, Taichi; Koyama, Kazuya

    2014-07-01

    We study DBI spinflation models with angular potentials that are derived in string theory. We analyze the background dynamics with different parameter sets and study the impact of changing each parameter on inflationary dynamics. It is known that the conversion of the entropy perturbation into the curvature perturbation gives multifield Dirac-Born-Infeld (DBI) inflation models a possibility of satisfying the observational constraints by relaxing the stringent microphysical constraint that disfavors single-field DBI inflation models. We show that our model is excluded by the Planck satellite observations even with the conversion mechanism regardless of the parameter set.

  18. Continuing quality improvement procedures for a clinical PACS.

    PubMed

    Andriole, K P; Gould, R G; Avrin, D E; Bazzill, T M; Yin, L; Arenson, R L

    1998-08-01

    The University of California at San Francisco (USCF) Department of Radiology currently has a clinically operational picture archiving and communication system (PACS) that is thirty-five percent filmless, with the goal of becoming seventy-five percent filmless within the year. The design and implementation of the clinical PACS has been a collaborative effort between an academic research laboratory and a commercial vendor partner. Images are digitally acquired from three computed radiography (CR) scanners, five computed tomography (CT) scanners, five magnetic resonance (MR) imagers, three digital fluoroscopic rooms, an ultrasound mini-PACS and a nuclear medicine mini-PACS. The DICOM (Digital Imaging and Communications in Medicine) standard communications protocol and image format is adhered to throughout the PACS. Images are archived in hierarchical staged fashion, on a RAID (redundant array of inexpensive disks) and on magneto-optical disk jukeboxes. The clinical PACS uses an object-oriented Oracle SQL (systems query language) database, and interfaces to the Radiology Information System using the HL7 (Health Languages 7) standard. Components are networked using a combination of switched and fast ethernet, and ATM (asynchronous transfer mode), all over fiber optics. The wide area network links six UCSF sites in San Francisco. A combination of high and medium resolution dual-monitor display stations have been placed throughout the Department of Radiology, the Emergency Department (ED) and Intensive Care Units (ICU). A continuing quality improvement (CQI) committee has been formed to facilitate the PACS installation and training, workflow modifications, quality assurance and clinical acceptance. This committee includes radiologists at all levels (resident, fellow, attending), radiology technologists, film library personnel, ED and ICU clinician end-users, and PACS team members. The CQI committee has proved vital in the creation of new management procedures, providing a

  19. Java-based cryptosystem for PACS and tele-imaging

    NASA Astrophysics Data System (ADS)

    Tjandra, Donny; Wong, Stephen T. C.; Yu, Yuan-Pin

    1998-07-01

    Traditional PACS systems are based on two-tier client server architectures, and require the use of costly, high-end client workstations for image viewing. Consequently, PACS systems using the two-tier architecture do not scale well as data increases in size and complexity. Furthermore, use of dedicated viewing workstations incurs costs in deployment and maintenance. To address these issues, the use of digital library technologies, such as the World Wide Web, Java, and CORBA, is being explored to distribute PACS data to serve a broader range of healthcare providers in an economic and efficient manner. Integration of PACS systems with digital library technologies allows access to medical information through open networks such as the Internet. However, use of open networks to transmit medical data introduces problems with maintaining privacy and integrity of patient information. Cryptography and digital timestamping is used to protect sensitive information from unauthorized access or tampering. A major concern when using cryptography and digital timestamping is the performance degradation associated with the mathematical calculations needed to encrypt/decrypt an image dataset, or to calculate the hash value of an image. The performance issue is compounded by the extra layer associated with the CORBA middleware, and the use of programming languages interpreted at the client side, such as Java. This paper study the extent to which Java-based cryptography and digital timestamping affects performance in a PACS system integrated with digital library technologies.

  20. DICOM data migration for PACS transition: procedure and pitfalls.

    PubMed

    van Ooijen, Peter M A; Aryanto, Kadek Yota; Broekema, André; Horii, Steven

    2015-07-01

    Transition from one Picture Archiving and Communication System (PACS) to the other is costly and disruptive. Especially the migration of the DICOM data from the legacy to the new PACS is a very challenging task, and although such a migration will happen in every hospital, literature on methodologies to follow and possible problems and pitfalls is scarce. The objective of this work is to provide insight in the prerequisites for the legacy PACS before starting the migration with respect to vendor and DICOM considerations. The steps involved in migration, possible methodologies, and areas of specific interest when planning migration are given. Possible challenges and problems are defined as well as issues that are often overlooked. A step-wise approach should be implemented for data migration. Careful planning and testing, continuous observation of the process, and involvement of all stakeholders including the old and new vendors are crucial for a successful transition from one PACS to the other. A proper test migration is a crucial step in the PACS transition process, which can eliminate many of the problems in the actual migration. However, with any migration, there has to be a willingness to take a limited amount of risk since not all problems can nor will be identified in the test migration.

  1. Orbital angular momentum microlaser

    NASA Astrophysics Data System (ADS)

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M.; Feng, Liang

    2016-07-01

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes.

  2. Orbital angular momentum microlaser.

    PubMed

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M; Feng, Liang

    2016-07-29

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes. Copyright © 2016, American Association for the Advancement of Science.

  3. Supercritical fluid extraction (SFE) of cranberries does not extract oligomeric proanthocyanidins (PAC) but does alter the chromatography and bioactivity of PAC fractions extracted from SFE residues.

    PubMed

    Feliciano, Rodrigo P; Meudt, Jennifer J; Shanmuganayagam, Dhanansayan; Metzger, Brandon T; Krueger, Christian G; Reed, Jess D

    2014-08-06

    Supercritical fluid extraction (SFE) removed lipophilic compounds and low molecular weight flavonoids from cranberries. However, SFE did not extract proanthocyanidins (PAC). The SFE PAC-enriched residue was submitted to fractionation on Sephadex LH-20 using ethanol, ethanol/methanol, and 80% acetone. PAC degree of polymerization (DP) and ratios of "A-type" to "B-type" interflavan bonds were compared with those of PAC fractions without SFE. Mass spectrometry showed that when SFE was used, PAC distribution was shifted toward higher DP and contained higher amounts of two and three "A-type" bonds compared to PAC fractions without SFE. The 80% acetone fraction with SFE had significantly greater extraintestinal pathogenic Escherichia coli (ExPEC) agglutination and significantly lower ExPEC invasion of enterocytes than the fraction without SFE. Cranberry PAC with higher numbers of "A-type" interflavan bonds are more bioactive in agglutinating ExPEC and inhibiting ExPEC enterocyte invasion.

  4. Instantons from perturbation theory

    NASA Astrophysics Data System (ADS)

    Serone, Marco; Spada, Gabriele; Villadoro, Giovanni

    2017-07-01

    In quantum mechanics and quantum field theory perturbation theory generically requires the inclusion of extra contributions nonperturbative in the coupling, such as instantons, to reproduce exact results. We show how full nonperturbative results can be encoded in a suitable modified perturbative series in a class of quantum mechanical problems. We illustrate this explicitly in examples which are known to contain nonperturbative effects, such as the (supersymmetric) double-well potential, the pure anharmonic oscillator, and the perturbative expansion around a false vacuum.

  5. Automated Lattice Perturbation Theory

    SciTech Connect

    Monahan, Christopher

    2014-11-01

    I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.

  6. Sentinel-1 And Sentinel-3 OLCI PAC At DLR

    NASA Astrophysics Data System (ADS)

    Hahmann, Thomas; Weber, Hans; Diedrich, Erhard; Schreier, Gunter

    2013-12-01

    GMES / Copernicus is the European Earth Observation Programme, conducted jointly by the EC, ESA, EUMETSAT and the member states. The Sentinel satellites (Copernicus space segment) are expected to be launched in 2014 (Sentinel-1A, -2A, and -3A). The core payload data ground segment (PDGS) is managed by ESA and operated by national partners. In this core ground segment, the DLR German Remote Sensing Data Center (DFD) was selected to install and operate Processing and Archiving Centers (PACs) for Sentinel-1 and Sentinel-3-OLCI. This paper describes the current status of the project “Preparation and Operations of the Sentinel-1 and Sentinel-3 OLCI Off- line Processing and Archiving Centre at DLR Oberpfaffenhofen (S1-PAC / S3-OLCI-PAC)”.

  7. Performance characteristics of the Mayo/IBM PACS

    NASA Astrophysics Data System (ADS)

    Persons, Kenneth R.; Gehring, Dale G.; Pavicic, Mark J.; Ding, Yingjai

    1991-07-01

    The Mayo Clinic and IBM (at Rochester, Minnesota) have jointly developed a picture archiving system for use with Mayo's MRI and Neuro CT imaging modalities. The communications backbone of the PACS is a portion of the Mayo institutional network: a series of 4-Mbps token rings interconnected by bridges and fiber optic extensions. The performance characteristics of this system are important to understand because they affect the response time a PACS user can expect, and the response time for non-PACS users competing for resources on the institutional network. The performance characteristics of each component and the average load levels of the network were measured for various load distributions. These data were used to quantify the response characteristics of the existing system and to tune a model developed by North Dakota State University Department of Computer Science for predicting response times of more complex topologies.

  8. Cardiac PACS: strategies for planning, integration & vendor selection.

    PubMed

    Bruski, Georgann B; Cutler, Sara

    2003-01-01

    Cardiologists are clamoring for better imaging techniques, the ability to view images from their office or home, and for the resulting improvement in efficiency which translates into increased profitability. The future is here; are you ready? Cardiac systems have developed into full-blown information management and digital imaging systems. Hospitals are moving aggressively to update their cardiac information systems and identifying the significant role the CIS (cardiac information system) plays in the selection process. It is important to plan the infrastructure of your cardiac PACS (picture archival communication system) and determine how it will integrate with the radiology PACS. Equally important is the integration potential with other hospital information systems such as the laboratory, pharmacy and billing, etc. Answers to these decision factors are provided in addition to information pertaining to the overall cardiac PACS planning process and vendor offerings.

  9. Tablet PC as a mobil PACS terminal using wireless LAN

    NASA Astrophysics Data System (ADS)

    Tsao, Bo-Shen; Ching, Yu-Tai; Lee, Wen-Jeng; Chen, Shyh-Jye; Chang, Chia-Hung; Chen, Chien-Jung; Yen, York; Lee, Yuan-Ten

    2003-05-01

    A PACS mobile terminal has applications in ward round, emergency room and remote teleradiology consultation. Personal Digital Assistants (PDAs) have the highest mobility and are used for many medical applications. However, their roles are limited in the field of radiology due to small screen size. In this study, we built a wireless PACS terminal using a hand-held tablet-PC. A tablet PC (X-pilot, LEO systems, Taiwan) running the WinCE operating systems was used as our mobile PACS terminal. This device is equipped with 800×600 resolution 10.4 inch TFT monitor. The network connection between the tablet PC and the server was linked via wireless LAN (IEEE 802.11b).

  10. PACS-Based Computer-Aided Detection and Diagnosis

    NASA Astrophysics Data System (ADS)

    Huang, H. K. (Bernie); Liu, Brent J.; Le, Anh HongTu; Documet, Jorge

    The ultimate goal of Picture Archiving and Communication System (PACS)-based Computer-Aided Detection and Diagnosis (CAD) is to integrate CAD results into daily clinical practice so that it becomes a second reader to aid the radiologist's diagnosis. Integration of CAD and Hospital Information System (HIS), Radiology Information System (RIS) or PACS requires certain basic ingredients from Health Level 7 (HL7) standard for textual data, Digital Imaging and Communications in Medicine (DICOM) standard for images, and Integrating the Healthcare Enterprise (IHE) workflow profiles in order to comply with the Health Insurance Portability and Accountability Act (HIPAA) requirements to be a healthcare information system. Among the DICOM standards and IHE workflow profiles, DICOM Structured Reporting (DICOM-SR); and IHE Key Image Note (KIN), Simple Image and Numeric Report (SINR) and Post-processing Work Flow (PWF) are utilized in CAD-HIS/RIS/PACS integration. These topics with examples are presented in this chapter.

  11. Density matrix perturbation theory.

    PubMed

    Niklasson, Anders M N; Challacombe, Matt

    2004-05-14

    An orbital-free quantum perturbation theory is proposed. It gives the response of the density matrix upon variation of the Hamiltonian by quadratically convergent recursions based on perturbed projections. The technique allows treatment of embedded quantum subsystems with a computational cost scaling linearly with the size of the perturbed region, O(N(pert.)), and as O(1) with the total system size. The method allows efficient high order perturbation expansions, as demonstrated with an example involving a 10th order expansion. Density matrix analogs of Wigner's 2n+1 rule are also presented.

  12. The Photoconductor Array Camera & Spectrometer (PACS) instrument for Herschel.

    NASA Astrophysics Data System (ADS)

    Ali, Babar; Frayer, D. T.; Fadda, D.; Appleton, P.; Latter, B.

    2007-05-01

    PACS is one of three science instruments for ESA ’ s Herschel Space Observatory (HSO, formerly known as FIRST). It operates either as an imaging photometer or an integral field spectrometer over the spectral band from 57 to 210 µm. PACS is being designed and built by a consortium of institutes and university departments from across Europe under the leadership of Principal Investigator Albrecht Poglitsch located at Max-Planck-Institute for Extraterrestrial Physics (MPE), Garching, Germany. Consortium members are: Austria: UVIE; Belgium: IMEC, KUL, CSL; France: CEA, OAMP; Germany: MPE, MPIA; Italy: IFSI, OAP/OAT, OAA/CAISMI, LENS, SISSA; Spain: IAC.

  13. MIRIAM: the PACS project in Paris: overview and implementation.

    PubMed

    Primo, H; Picard, J E

    1997-08-01

    In this article the authors describe the Management Informatique de la Radiologie et de l'Imagerie Médicale (MIRIAM) major picture archiving and communication system (PACS) project in Paris, France. The Assistance Publique of Paris, France is a healthcare provider and took the initiative to start the largest PACS program in Europe to date. The MIRIAM project will start in 1997 and will be used in different, consecutive phases. A consortium of several companies is in charge of the implementation. Thirty-three hospitals with 54 imaging departments will be integrated in one system.

  14. Intrinsic Angular Momentum of Light.

    ERIC Educational Resources Information Center

    Santarelli, Vincent

    1979-01-01

    Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

  15. Lunar occultation angular diameter measurements.

    NASA Astrophysics Data System (ADS)

    Beavers, W. I.; Eitter, J. J.; Dunham, D. W.; Stein, W. L.

    1980-11-01

    The analysis of one dozen lunar occultation diameter candidate observations are reported. Within this set of occultation measurements at Fick Observatory, six of the stars provide sensible angular diameters, and the remainder appear as virtual point sources. Angular diameter measurements are reported for ɛ Gem, BD+24°0571, υ Cap, R Gem, and BD+23°1518.

  16. Intrinsic Angular Momentum of Light.

    ERIC Educational Resources Information Center

    Santarelli, Vincent

    1979-01-01

    Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

  17. Switching mechanism senses angular acceleration

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Switching mechanism actuates an electrical circuit when a predetermined angular acceleration and displacement are reached. A rotor in the mechanism overcomes the restraint of a magnetic detent when the case in which the detent is mounted reaches the predetermined angular acceleration.

  18. Herschel/PACS detection of far-IR OH emission towards the Orion Bar PDR

    NASA Astrophysics Data System (ADS)

    Goicoechea, J. R.; Joblin, C.; Contursi, A.; Berne, O.; Cernicharo, J.; Gerin, M.; Le Bourlot, J.; Bergin, E. A.; Bell, T. A.; Rollig, A.; HEXOS-GT-KP Team

    2011-05-01

    Due to its much improved angular resolution and sensitivity compared to previous far-IR space missions, Herschel observations are providing a new perspective of the chemistry and thermal balance in photodissociation regions (PDRs; the Orion Bar, the Horsehead, etc.). As part of a far-IR spectral scan with Herschel/PACS, we present the first detection of OH, a key molecule in the oxygen-network, towards the Orion Bar. Five OH rotational Λ-doublets involving energy levels out to Eu/k 511 K have been detected (at 65, 79, 84, 119 and 163um). The observed emission of rotationally excited OH lines is extended and correlates well with the high-J CO and CH+ J=3-2 line emission also detected by PACS, thus pointing towards a common origin, but apparently does not correlate with the observed water vapour emission. Nonlocal, non-LTE radiative transfer models including excitation by the ambient FIR radiation field suggest that OH arises in a small filling factor component of warm (Tk~160-220 K) and dense (nH~106-7 cm-3) gas with source-averaged OH column densities of ~1015 cm-2. High density and temperature photochemical models predict such enhanced OH columns at low depths (AV~1) and small spatial scales, where OH formation is driven by gas-phase endothermic reactions of atomic oxygen with molecular hydrogen. We interpret the extended OH emission as coming from unresolved structures exposed to FUV radiation near the Bar edge (photoevaporating clumps or filaments) and not from the lower density ``interclump'' medium. FUV photodissociation leads to OH/H2O abundance ratios (>1) much higher than those expected in equally warm regions without enhanced FUV radiation fields.

  19. Parents as Agents of Change (PAC) in pediatric weight management: The protocol for the PAC randomized clinical trial

    PubMed Central

    2012-01-01

    Background There is an urgent need to develop and evaluate weight management interventions to address childhood obesity. Recent research suggests that interventions designed for parents exclusively, which have been named parents as agents of change (PAC) approaches, have yielded positive outcomes for managing pediatric obesity. To date, no research has combined a PAC intervention approach with cognitive behavioural therapy (CBT) to examine whether these combined elements enhance intervention effectiveness. This paper describes the protocol our team is using to examine two PAC-based interventions for pediatric weight management. We hypothesize that children with obesity whose parents complete a CBT-based PAC intervention will achieve greater reductions in adiposity and improvements in cardiometabolic risk factors, lifestyle behaviours, and psychosocial outcomes than children whose parents complete a psycho-education-based PAC intervention (PEP). Methods/Design This study is a pragmatic, two-armed, parallel, single-blinded, superiority, randomized clinical trial. The primary objective is to examine the differential effects of a CBT-based PAC vs PEP-based PAC intervention on children’s BMI z-score (primary outcome). Secondary objectives are to assess intervention-mediated changes in cardiometabolic, lifestyle, and psychosocial variables in children and parents. Both interventions are similar in frequency of contact, session duration, group facilitation, lifestyle behaviour goals, and educational content. However, the interventions differ insofar as the CBT-based intervention incorporates theory-based concepts to help parents link their thoughts, feelings, and behaviours; these cognitive activities are enabled by group leaders who possess formal training in CBT. Mothers and fathers of children (8–12 years of age; BMI ≥85th percentile) are eligible to participate if they are proficient in English (written and spoken) and agree for at least one parent to attend

  20. Want to Teach about SuperPACs? What We Can Learn from Stephen Colbert

    ERIC Educational Resources Information Center

    Stoddard, Jeremy

    2012-01-01

    The emergence of the SuperPACs in American politics is a major issue in the current election. SuperPACs, and the media campaigns they fund, also present a major challenge for media and democratic education. This article explores the issues surrounding SuperPACs and the rise of media in elections and politics in general, and presents some starting…

  1. 75 FR 31788 - Appointments to the Medicare Payment Advisory Commission (MedPAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... OFFICE Appointments to the Medicare Payment Advisory Commission (MedPAC) AGENCY: Government... the Medicare Payment Advisory Commission (MedPAC) and gave the Comptroller General responsibility for...., Washington, DC 20548. MedPAC: 601 New Jersey Avenue, NW., Suite 9000, Washington, DC 20001. FOR...

  2. Removal of anionic contaminants by surfactant modified powdered activated carbon (SM-PAC) combined with ultrafiltration.

    PubMed

    Hong, Hye-Jin; Kim, Hojeong; Lee, You-Jin; Yang, Ji-Won

    2009-10-30

    A variety of inorganic contaminants may form toxic oxyanions in aqueous systems which pose significant hazard to human health and the ecosystem. In order to remove the oxyanions from aqueous stream effectively, surfactant-modified powdered activated carbon (SM-PAC) combined with ultrafiltration (UF) was proposed in this study. As the cationic surfactant, cetylpyridinium chloride (CPC), adsorbs on the surface of PAC, the zeta potential of PAC increases to +40 mV. Oxyanions such as chromate, ferricyanide and arsenate bind on SM-PAC by electrostatic interaction, then the contaminants bound with SM-PAC can be separated by UF membrane. 0.3 mM of chromate and ferricyanide are removed completely with 4.0 g/L of SM-PAC. In case of arsenate, the removal efficiency was lower than chromate and ferricyanide. It is considered that the competition occurs among anionic pollutants on the limited binding sites of SM-PAC and lower valence of arsenate results in the lower removal efficiency. High permeate flux is maintained during filtration. The spent SM-PAC was regenerated by the concentrated Cl(-) solutions. NaCl solution whose molar Cl(-) concentration is 1.4 times higher than the contaminants bound on SM-PAC was optimal for the regeneration. Regenerated SM-PAC exhibited similar adsorption capacity to fresh SM-PAC. SM-PAC combined with UF can effectively remove anionic contaminants. Moreover, the simple and efficient regeneration process is proposed.

  3. Want to Teach about SuperPACs? What We Can Learn from Stephen Colbert

    ERIC Educational Resources Information Center

    Stoddard, Jeremy

    2012-01-01

    The emergence of the SuperPACs in American politics is a major issue in the current election. SuperPACs, and the media campaigns they fund, also present a major challenge for media and democratic education. This article explores the issues surrounding SuperPACs and the rise of media in elections and politics in general, and presents some starting…

  4. Documentation of 9-PAC Beacon Target Detector processing function

    NASA Astrophysics Data System (ADS)

    Gertz, Jeffrey L.; Elkin, Gabriel R.

    1994-07-01

    This project report documents the algorithms and flow of the beacon target detector (BTD) processing function incorporated as part of the ASR-9 processor augmentation card (9-PAC). The BTD function combines replies that arise from the same aircraft to form beacon targets, and sends these beacon targets to the 9-PAC merge process where they are combined with primary radar reports. The 9-PAC BTD process was designed to solve two problems with the ASR-9 array signal processor (ASP) BTD: identifying and removing false beacon targets due to reflections and preventing merging or splitting of targets due to reply overlap and garble. The BTD reflection processing algorithm marks each beacon target as either real or false, and provides this information to the 9-PAC merge process. Discrete Mode A reflection false targets are identified when duplicate code reports satisfying stringent conditions are located. In order to find nondiscrete Mode A code reflection false targets, the BTD builds an automated, dynamic reflector database based on the geography of pairs of discrete real and false targets.

  5. NARSTO PAC2001 GVRD CAPMON AIR QUAL DATA

    Atmospheric Science Data Center

    2014-04-25

    NARSTO PAC2001 GVRD CAPMON AIR QUAL DATA Project Title:  NARSTO Discipline:  ... Order:   ASDC Order Tool Parameters:  Air Temperature Humidity Upper Level Winds Ozone Aerosol Particle ... Related Data:  Spatial Coverage: Canada Pacific 2001 Air Quality Study SCAR-B Block:  ...

  6. Assessing The Impact Of Computed Radiography And PACS

    NASA Astrophysics Data System (ADS)

    Hedgcock, Marcus W.; Kehr, Katherine

    1989-05-01

    Our institution (San Francisco VA Medical Center) is a VA pilot center for total digital imaging and PACS. Quantitative information about PACS impact on health care is limited, because no centers have done rigorous preimplementation studies. We are gathering quantitative service delivery and cost data before, during, and after stepwise implementation of computed radiography and PACS at our institution to define the impact on imaging service delivery. We designed a simple audit method using the x-ray request and time clocks to determine patient waiting time, imaging time, film use, image availability to the radiologist, matching of current with previous images, image availability to clinicians, and time to final interpretation. Our department model is a multichannel, mulitserver patient queue. Our current radiograph file is space limited, containing only one year of images; older images are kept in a remote file area in another building. In addition, there are 16 subfile areas within the Radiology Service and the medical center. Our preimplementation audit showed some long waiting times (40 minutes, average 20) and immediate retrieval of prior films in only 42% of cases, with an average retrieval time of 22 hours. Computed radiography and the optical archive have the potential to improve these figures. The audit will be ongoing and automated as implementation of PACS progresses, to measure service improvement and learning curve with the new equipment. We present the audit format and baseline preimplementation figures.

  7. Hospital PACS (Picture Archiving And Control System) Network Simulation Studies

    NASA Astrophysics Data System (ADS)

    Lawrence, G. R.; Marin, G. A.; Naron, S. E.

    1986-06-01

    The nation's hospitals have long used distributed data processing as a means of reducing operational costs and providing timely service. Radiology Departments are now also taking advantage of these facilities in order to decrease the cost of producing and archiving radiological images. A typical medium scale hospital consumes large quantities of silver oxide film which, along with attendant labor costs, is expensive compared with costs for digital image processing technology now available. Using this technology large image files can be stored and retrieved through local area networks that can also support the transaction traffic essential in a hospital environment. The evolving systems are called Picture Archiving and Control Systems (PACS). PACS will include radiology imaging equipment, distributed and central image archiving facilities, and significant numbers of user work-stations and graphics display nodes. The devices will be interconnected by high speed local area networks capable of distributing information ranging from simple control messages to large image files of several megabytes in a fashion offering most users a response time of several seconds. This paper will illustrate the PACS system concept, present a queuing model approach to analyzing PACS performance, and discuss results acquired for a variety of parametric samples. The IBM Research Queuing Package (RESQ) has been used for the exercise and will be discussed sufficiently for the reader to appreciate its capability. RESQ simulation results indicate that system response times will be more dependent on the internal architecture and programs of the workstation than on the speed of the transmission media.

  8. PACSman: IDL Suite for Herschel/PACS spectrometer data

    NASA Astrophysics Data System (ADS)

    Lebouteiller, Vianney; Cormier, Diane

    2017-08-01

    PACSman provides an alternative for several reduction and analysis steps performed in HIPE (ascl:1111.001) on PACS spectroscopic data; it is written in IDL. Among the operations possible with it are transient correction, line fitting, map projection, and map analysis, and unchopped scan, chop/nod, and the decommissioned wavelength switching observation modes are supported.

  9. Enterprise-scale image distribution with a Web PACS.

    PubMed

    Gropper, A; Doyle, S; Dreyer, K

    1998-08-01

    The integration of images with existing and new health care information systems poses a number of challenges in a multi-facility network: image distribution to clinicians; making DICOM image headers consistent across information systems; and integration of teleradiology into PACS. A novel, Web-based enterprise PACS architecture introduced at Massachusetts General Hospital provides a solution. Four AMICAS Web/Intranet Image Servers were installed as the default DICOM destination of 10 digital modalities. A fifth AMICAS receives teleradiology studies via the Internet. Each AMICAS includes: a Java-based interface to the IDXrad radiology information system (RIS), a DICOM autorouter to tape-library archives and to the Agfa PACS, a wavelet image compressor/decompressor that preserves compatibility with DICOM workstations, a Web server to distribute images throughout the enterprise, and an extensible interface which permits links between other HIS and AMICAS. Using wavelet compression and Internet standards as its native formats, AMICAS creates a bridge to the DICOM networks of remote imaging centers via the Internet. This teleradiology capability is integrated into the DICOM network and the PACS thereby eliminating the need for special teleradiology workstations. AMICAS has been installed at MGH since March of 1997. During that time, it has been a reliable component of the evolving digital image distribution system. As a result, the recently renovated neurosurgical ICU will be filmless and use only AMICAS workstations for mission-critical patient care.

  10. Digital processing of radiographic images from PACS to publishing.

    PubMed

    Christian, M E; Davidson, H C; Wiggins, R H; Berges, G; Cannon, G; Jackson, G; Chapman, B; Harnsberger, H R

    2001-03-01

    Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.

  11. PACS and Digital Medicine: Essential Principles and Modern Practice.

    PubMed

    Langer, Steve G

    2012-10-01

    PACS and Digital Medicine: Essential Principles and Modern Practice. Y. Liu J. Wang CRC, Taylor & Francis Group, Boca Raton, FL, 2011. Hardcover, 367 pp. Price: $135.95. ISBN: 978-1-4200-83651. © 2012 American Association of Physicists in Medicine.

  12. Operator interface design considerations for a PACS information management system

    NASA Astrophysics Data System (ADS)

    Steinke, James E.; Nabijee, Kamal H.; Freeman, Rick H.; Prior, Fred W.

    1990-08-01

    As prototype PACS grow into fully digital departmental and hospital-wide systems, effective information storage and retrieval mechanisms become increasingly important. Thus far, designers of PACS workstations have concentrated on image communication and display functionality. The new challenge is to provide appropriate operator interface environments to facilitate information retrieval. The "Marburg Model" 1 provides a detailed analysis of the functions, control flows and data structures used in Radiology. It identifies a set of "actors" who perform information manipulation functions. Drawing on this model and its associated methodology it is possible to identify four modes of use of information systems in Radiology: Clinical Routine, Research, Consultation, and Administration. Each mode has its own specific access requirements and views of information. An operator interface strategy appropriate for each mode will be proposed. Clinical Routine mode is the principal concern of PACS primary diagnosis workstations. In a full PACS implementation, such workstations must provide a simple and consistent navigational aid for the on-line image database, a local work list of cases to be reviewed, and easy access to information from other hospital information systems. A hierarchical method of information access is preferred because it provides the ability to start at high-level entities and iteratively narrow the scope of information from which to select subsequent operations. An implementation using hierarchical, nested software windows which fulfills such requirements shall be examined.

  13. PACS implementation dramatically impacts people and radiology work processes

    NASA Astrophysics Data System (ADS)

    Ouvry, Ann

    1997-05-01

    The technology is not the bottleneck anymore in PACS implementation, it has become clear that the key to the success of PACS is understanding the current process, the end-user requirements, and how these processes will change with the introduction of PACS. We will discuss how implementation of PACS changed the working procedures in the Radiology department of Visby Hospital. Visby Hospital in Gotland, Sweden has approximately 160 beds. The Radiology department performs approximately 33,000 examinations per year and is capable of offering a broad range of diagnostic imaging services including CT and MRI. When a new facility was built in 1994, the decision was made to go for filmless operation and a modern information infrastructure. The new facility went operational by the end of 1994, in August 1995 almost filmless operation was reached. Continuing effort and attention is being paid to further simplify the workflow and working procedures in the Radiology department, and to improve the services offered to referring physicians. Although the project aimed at filmless operation, the main goal was to organize for efficient operation and excellent service, thereby maintaining high quality standards and employee satisfaction.

  14. Full PACS installation in Seoul National University Hospital, Korea

    NASA Astrophysics Data System (ADS)

    Lim, HyunWoo; Kim, DongOok; Ahn, JinYoung; Lee, DongHyuk; Lee, JinHyung; Park, HeeJung; Kim, JongHyo; Han, Jungu

    2002-05-01

    Seoul National University Hospital (SNUH) is composed of two buildings and has more than 1500 beds for patients needing hospitalization. Marotech has provided full PACS to SNUH with total HIS Integration in this year. In this paper, the installation process and management experience for seven months will be presented. At SNUH, 1643.8 exams were held per day during seven month after PACS installation. It is about 40 Gigabytes per day. Two acquisition servers (ACQ 1, 2), two database servers (DB 1, 2), two storage servers (LTA, network attached storage-NAS), one backup server (DLT) totally 8 servers were installed. SNUH has 11 CRs, 4 CTs, 3 MRIs, 9 NMs, 4 RFs, 20 USs, 7 ESs, 4 SCs, 5 XAs, and 5 Film Ditigers. All these modalities were integrated with PACS. DICOM 3.0 standard was conformed for images. DICOM Gateways were installed for modalities that do not support DICOM. The doctor can query and view Endoscopes, pathologic and anatomic data as well as radiological data. All the past five years exams is accessed less than 10 Seconds via on-line. Through the cooperation with SNUH and Marotech, HIS and PACS work together in stable state. These systems were integrated with HL7 standards and IHE.

  15. Patriot Advanced Capability-3 Missile Segment Enhancement (PAC-3 MSE)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-492 Patriot Advanced Capability-3 Missile Segment Enhancement (PAC-3 MSE) As of FY 2017...Program Manager POE - Program Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost

  16. 24 CFR 891.735 - Notice upon PAC expiration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Notice upon PAC expiration. 891.735 Section 891.735 Housing and Urban Development Regulations Relating to Housing and Urban Development... AND URBAN DEVELOPMENT (SECTION 8 HOUSING ASSISTANCE PROGRAMS, SECTION 202 DIRECT LOAN PROGRAM, SECTION...

  17. Millennium regional PACS management: strategies for successful implementation

    NASA Astrophysics Data System (ADS)

    Levin, Brad; Romlein, John R.; Gac, Robert J., Jr.; Chacko, Anna K.; Radvany, Martin

    2000-05-01

    With the advent of the new Millennium, Picture Archive and Communications System (PACS) technology has matured to levels sufficient to support open systems based, regional implementations. This shifts the site-centric PACS paradigm into broader scale, impacting facilities, workflow, business plans and ultimately patient care on a regional basis. Prudent and effective management of a regional implementation is critical to overall project success based upon a number of competing influences fundamental to the PACS including network infrastructure, clinical workflow, acquisition modalities, planning documentation, site preparation, acceptance testing, project communication, interface integration issues, etc. Risk mitigation is possible by understanding and managing the interrelationships of these influences through a phased approach with embedded management controls. The overall phases of regional implementation are not unlike site-centric implementations, consisting of Discovery, Planning, Preparation, Installation; Acceptance and Warranty/Maintenance; however, details which manifest over time are what provide significant management challenges. When balanced using a culturally reinforced policy of open, frequent and hands-on communication, regional PACS projects can be successfully implemented maintaining budget, schedule and scope thresholds.

  18. Proton Radiography as an electromagnetic field and density perturbation diagnostic

    SciTech Connect

    Mackinnon, A; Patel, P; Town, R; Edwards, M; Phillips, T; Lerner, S; Price, D; Hicks, D; Key, M; Hatchett, S; Wilks, S; King, J; Snavely, R; Freeman, R; Boehlly, T; Koenig, M; Martinolli, E; Lepape, S; Benuzzi-Mounaix, A; Audebert, P; Gauthier, J; Borghesi, M; Romagnani, L; Toncian, T; Pretzler, G; Willi, O

    2004-04-15

    Laser driven proton beams have been used to diagnose transient fields and density perturbations in laser produced plasmas. Grid deflectometry techniques have been applied to proton radiography to obtain precise measurements of proton beam angles caused by electromagnetic fields in laser produced plasmas. Application of proton radiography to laser driven implosions has demonstrated that density conditions in compressed media can be diagnosed with MeV protons. This data has shown that proton radiography can provide unique insight into transient electromagnetic fields in super critical density plasmas and provide a density perturbation diagnostics in compressed matter . PACS numbers: 52.50.Jm, 52.40.Nk, 52.40.Mj, 52.70.Kz

  19. Doxycycline exerted neuroprotective activity by enhancing the activation of neuropeptide GPCR PAC1.

    PubMed

    Yu, Rongjie; Zheng, Lijun; Cui, Yue; Zhang, Huahua; Ye, Heng

    2016-04-01

    Doxycycline has significant neuroprotective effect with anti-inflammatory and anti-apoptotic activity. We found for the first time that doxycycline specially promoted the proliferation of Chinese hamster ovary (CHO) cells with high expression of neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) preferring G protein-coupled receptor (GPCR), PACAP receptor 1(PAC1) and induced the internalization of PAC1 tagged with yellow fluorescent protein (YFP) indicating doxycycline interacted with PAC1. The homology modeling of PAC1 and molecular docking of doxycycline with PAC1 showed the theoretical binding of doxycycline to PAC1 at the site where PACAP(30-37) recognized. The competition binding assay and PAC1 site-specific mutation of Asp116, which formed two hydrogen bonds with Dox, confirmed the binding of doxycycline to PAC1 imitating PACAP(30-37). Doxycycline (100 ng/mL) significantly promoted the proliferative activities of vasoactive intestinal polypeptide (VIP) and oligopeptide HSDGIF responsible for the activation of PAC1 in PAC1-CHO cells, indicating that doxycycline facilitated the binding and the activation of PAC1 imitating PACAP(28-38). In Neuro2a cells with endogenous expression of PAC1 and its ligands, doxycycline not only promoted the proliferation of Neuro2a cells but also protected the cells from scopolamine induced apoptosis, which was inhibited by cAMP-PKA signal pathway inhibitor H-89, PAC1 shRNA or PACAP antagonist PACAP(6-38). The in vivo study showed long-term treatment with doxycycline (100ug/kg) had significant effect against scopolamine induced amnesia, and the synergetic anti-apoptotic, anti-oxidative and neuroprotective effect of doxycycline with VIP was more efficient than doxycycline alone or VIP alone, indicating doxycycline enhanced the activation of PAC1 in vivo effectively. Furthermore, doxycycline analogue minocycline also had similar theoretically binding site on PAC1 to doxycycline and displayed corresponding

  20. Characterization of nanostructured HfO 2 films using RBS and PAC

    NASA Astrophysics Data System (ADS)

    Cavalcante, F. H. M.; Gomes, M. R.; Carbonari, A. W.; Pereira, L. F. D.; Rossetto, D. A.; Costa, M. S.; Alves, E.; Barradas, N. P.; Franco, N.; Redondo, L. M.; Lopes, A. M. L.; Soares, J. C.

    2012-02-01

    The hyperfine field at 181Ta lattice sites in a nanostructured HfO 2 thin film doped with Fe was studied using Rutherford Backscattering Spectrometry and Perturbed Angular Correlation techniques. The 409 nm Hf film was deposited by Electron Beam Evaporation on a silicon substrate. The radioactive 181Hf ions were produced by neutron activation of the nanofilm in the Brazilian Research Reactor (IPEN IEA-R1) by the reaction 180Hf(n,γ) 181Hf. These studies provided an excellent opportunity to obtain unique information regarding local arrangement of the grains, structure, phase transformations of nanoparticles and interfaces of nanostructured materials and the thin film.

  1. Integration of a clinical trial database with a PACS

    NASA Astrophysics Data System (ADS)

    van Herk, M.

    2014-03-01

    Many clinical trials use Electronic Case Report Forms (ECRF), e.g., from OpenClinica. Trial data is augmented if DICOM scans, dose cubes, etc. from the Picture Archiving and Communication System (PACS) are included for data mining. Unfortunately, there is as yet no structured way to collect DICOM objects in trial databases. In this paper, we obtain a tight integration of ECRF and PACS using open source software. Methods: DICOM identifiers for selected images/series/studies are stored in associated ECRF events (e.g., baseline) as follows: 1) JavaScript added to OpenClinica communicates using HTML with a gateway server inside the hospitals firewall; 2) On this gateway, an open source DICOM server runs scripts to query and select the data, returning anonymized identifiers; 3) The scripts then collects, anonymizes, zips and transmits selected data to a central trial server; 4) Here data is stored in a DICOM archive which allows authorized ECRF users to view and download the anonymous images associated with each event. Results: All integration scripts are open source. The PACS administrator configures the anonymization script and decides to use the gateway in passive (receiving) mode or in an active mode going out to the PACS to gather data. Our ECRF centric approach supports automatic data mining by iterating over the cases in the ECRF database, providing the identifiers to load images and the clinical data to correlate with image analysis results. Conclusions: Using open source software and web technology, a tight integration has been achieved between PACS and ECRF.

  2. Integrating DICOM conformant imaging equipment with a PACS

    NASA Astrophysics Data System (ADS)

    Duerinckx, Andre J.; Harmon, Craig; Crook, Michael; Grant, Edward G.

    1998-07-01

    Purpose/Background: As medical centers purchase commercial PACS to integrate with their imaging equipment, the fact that each component is often purchased at different times and with differing levels of DICOM conformance may become a problem. When the PACS is installed, major incompatibilities are often discovered between DICOM conformant pieces of equipment. Commercial PACS vendors are sometimes reluctant to take responsibility for the final integration of these components. The purpose of this paper is to document the nature and extent of these problem at one medical center, to report on how we are trying to solve them, and recommendations for the future. Methods: A large commercial PACS (IMPAXTM, Bayer Corporation, Agfa division) installed at the West Los Angeles VA medical Center was recently upgraded to be DICOM 3.0 conformant. Recently purchased DICOM conformant CT and MRI units and an older CT were already present. The problems in interfacing and integrating these imaging modalities with the upgraded DICOM-compliant PACS were investigated. Both software and hardware incompatibilities and human factors in bringing the different commercial vendors together were analyzed. Results: Major hardware and software incompatibilities were discovered. The use of DICOM-gateways is not always able to solve problems of incompatibility. The typical lag time between discovery of a problem and provision of a solution was 4 to 5 months. For more severe problems and also for a few of the lesser problems, resolution took over a year and is still ongoing. Repeated requests had to be made to the vendors to get together with us and solve these problems.

  3. Medical image security in a HIPAA mandated PACS environment.

    PubMed

    Cao, F; Huang, H K; Zhou, X Q

    2003-01-01

    Medical image security is an important issue when digital images and their pertinent patient information are transmitted across public networks. Mandates for ensuring health data security have been issued by the federal government such as Health Insurance Portability and Accountability Act (HIPAA), where healthcare institutions are obliged to take appropriate measures to ensure that patient information is only provided to people who have a professional need. Guidelines, such as digital imaging and communication in medicine (DICOM) standards that deal with security issues, continue to be published by organizing bodies in healthcare. However, there are many differences in implementation especially for an integrated system like picture archiving and communication system (PACS), and the infrastructure to deploy these security standards is often lacking. Over the past 6 years, members in the Image Processing and Informatics Laboratory, Childrens Hospital, Los Angeles/University of Southern California, have actively researched image security issues related to PACS and teleradiology. The paper summarizes our previous work and presents an approach to further research on the digital envelope (DE) concept that provides image integrity and security assurance in addition to conventional network security protection. The DE, including the digital signature (DS) of the image as well as encrypted patient information from the DICOM image header, can be embedded in the background area of the image as an invisible permanent watermark. The paper outlines the systematic development, evaluation and deployment of the DE method in a PACS environment. We have also proposed a dedicated PACS security server that will act as an image authority to check and certify the image origin and integrity upon request by a user, and meanwhile act also as a secure DICOM gateway to the outside connections and a PACS operation monitor for HIPAA supporting information. Copyright 2002 Elsevier Science Ltd.

  4. The Perturbed Puma Model

    NASA Astrophysics Data System (ADS)

    Rong, Shu-Jun; Liu, Qiu-Yu

    2012-04-01

    The puma model on the basis of the Lorentz and CPT violation may bring an economical interpretation to the conventional neutrinos oscillation and part of the anomalous oscillations. We study the effect of the perturbation to the puma model. In the case of the first-order perturbation which keeps the (23) interchange symmetry, the mixing matrix element Ue3 is always zero. The nonzero mixing matrix element Ue3 is obtained in the second-order perturbation that breaks the (23) interchange symmetry.

  5. Annihilation of angular momentum bias during thrusting and spinning-up maneuvers

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.; Kia, T.; Breckenridge, W. G.

    1989-01-01

    During spinning-up and thrusting maneuvers of rockets and spacecraft, undesired transverse torques (from error sources such as thruster misalignment, center-of-mass offset and thruster mismatch) perturb the angular momentum vector from its original orientation. In this paper a maneuver scheme is presented which virtually annihilates the angular momentum vector bias, even though the magnitude and direction of the perturbing body-fixed torques are unknown. In the analysis it is assumed that the torques are small and constant and that the spacecraft or rocket can be approximated by a rigid body, which may be asymmetric. Typical maneuvers of the Galileo spacecraft are simulated to demonstrate the technique.

  6. Annihilation of angular momentum bias during thrusting and spinning-up maneuvers

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.; Kia, T.; Breckenridge, W. G.

    1989-01-01

    During spinning-up and thrusting maneuvers of rockets and spacecraft, undesired transverse torques (from error sources such as thruster misalignment, center-of-mass offset and thruster mismatch) perturb the angular momentum vector from its original orientation. In this paper a maneuver scheme is presented which virtually annihilates the angular momentum vector bias, even though the magnitude and direction of the perturbing body-fixed torques are unknown. In the analysis it is assumed that the torques are small and constant and that the spacecraft or rocket can be approximated by a rigid body, which may be asymmetric. Typical maneuvers of the Galileo spacecraft are simulated to demonstrate the technique.

  7. Transverse angular momentum of photons

    SciTech Connect

    Aiello, Andrea

    2010-05-15

    We develop the quantum theory of transverse angular momentum of light beams. The theory applies to paraxial and quasiparaxial photon beams in vacuum and reproduces the known results for classical beams when applied to coherent states of the field. Both the Poynting vector, alias the linear momentum, and the angular-momentum quantum operators of a light beam are calculated including contributions from first-order transverse derivatives. This permits a correct description of the energy flow in the beam and the natural emergence of both the spin and the angular momentum of the photons. We show that for collimated beams of light, orbital angular-momentum operators do not satisfy the standard commutation rules. Finally, we discuss the application of our theory to some concrete cases.

  8. MBL Experiment in Angular Momentum

    NASA Astrophysics Data System (ADS)

    Gluck, Paul

    2002-04-01

    Among the series of beautiful take-home experiments designed by A.P. French and J.G. King for MIT students, the one on angular momentum studies the loss and conservation of angular momentum using a small dc motor as generator. Here we describe a version of the experiment that increases its accuracy, enables students to perform detailed rotational dynamics calculations, and sharpens the ability to isolate the region where the collision occurs.

  9. Perturbed nonlinear differential equations

    NASA Technical Reports Server (NTRS)

    Proctor, T. G.

    1974-01-01

    For perturbed nonlinear systems, a norm, other than the supremum norm, is introduced on some spaces of continuous functions. This makes possible the study of new types of behavior. A study is presented on a perturbed nonlinear differential equation defined on a half line, and the existence of a family of solutions with special boundedness properties is established. The ideas developed are applied to the study of integral manifolds, and examples are given.

  10. Effect of powdered activated carbon (PAC) and cationic polymer on biofouling mitigation in hybrid MBRs.

    PubMed

    Jamal Khan, S; Visvanathan, C; Jegatheesan, V

    2012-06-01

    In this study, the influence of powdered activated carbon (PAC) and cationic polymer (MPE50) was investigated on the fouling propensity in hybrid MBRs. Three laboratory scale MBRs were operated simultaneously including MBR(Control), MBR(PAC), and MBR(Polymer). Optimum dosages of PAC and polymer to the MBR(PAC) and MBR(Polymer), respectively were determined using jar tests. It was found that the MBR(PAC) exhibited low fouling tendency and prolonged filtration as compared to the other MBRs. Improved filtration in MBR(PAC) was attributed to the flocculation and adsorption phenomena. The effective stability of the biomass by PAC in the form of biological activated carbon (BAC) was verified by the increase in mean particle size. The BAC aided sludge layer exhibited porous cake structure resulting in the prolong filtration. However, both the membrane hybrid systems revealed effective adsorption of organic matter by 40% reduction in the soluble EPS concentration.

  11. Investigation on structural aspects of ZnO nano-crystal using radio-active ion beam and PAC

    NASA Astrophysics Data System (ADS)

    Ganguly, Bichitra Nandi; Dutta, Sreetama; Roy, Soma; Röder, Jens; Johnston, Karl; Martin, Manfred

    2015-11-01

    Nano-crystalline ZnO has been studied with perturbed angular correlation using 111mCd, implanted at ISOLDE/CERN and X-ray diffraction using Rietveld analysis. The data show a gradual increase in the crystal size and stress for a sample annealed at 600 °C, and reaching nearly properties of standard ZnO with tempering at 1000 °C. The perturbed angular correlation data show a broad frequency distribution at low annealing temperatures and small particle sizes, whereas at high annealing temperature and larger crystal sizes, results similar to bulk ZnO have been obtained. The ZnO nano-crystalline samples were initially prepared through a wet chemical route, have been examined by Fourier Transform Infrared Spectroscopy (FT-IR) and chemical purity has been confirmed with Energy Dispersive X-ray (EDAX) analysis as well as Transmission Electron Microscopy (TEM).

  12. Scalability, performance, and fault tolerance of PACS architectures

    NASA Astrophysics Data System (ADS)

    Blume, Hartwig R.; Prior, Fred W.; di Pierro, Milan C.; Goble, John C.; Lodgberg, Jonas; Kenney, Robert S.; Goeringer, Fred

    1998-07-01

    Three data-base architectures may be distinguished among Picture Archiving and Communication Systems (PACSs): (1) Configurations with logically and physically centralized data- base and file server, (2) systems with physically distributed file servers and a logically centralized data-base, and (3) installations with logically and physically distributed data- bases and file servers. A brief overview of these architectures and their scaleability, performance, and fault- tolerance is given. A PACS for an existing large university hospital is designed for the first as well as the second architecture using given image production data and workflow. We evaluate the fault-tolerance of the two architectures. By modeling the work-flow and employing queuing theory, solutions with practically realizable data transfer requirements are found for both architectures. With today's performance and cost of computers, storage, and information management technologies, the second and third architectures are preferably implemented, depending on the size of the installation. The architectures offer almost unlimited scaleability, very high fault-tolerance, and optimized workflow. We describe a modern commercial PACS that adheres to the open-systems concept and consists of software application programs that run, independent of specific computer and network components, on off-the-shelf hardware and under standard multi-platform operating systems and utilize commercial data-base management systems and network managers. The system is based on the second architecture with multiple islands of functionality, each with servers and archive modules and a physically distributed data-base. Our PACS architecture supports browser technology: Workstations use the data-base to determine the location of needed information and then, through the image browser, mount the appropriate file server for access. The architecture supports a concept similar to domain name server (DNS) directory services on the

  13. Angular momentum conservation law in light-front quantum field theory

    DOE PAGES

    Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

    2017-03-31

    We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. Wemore » also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

  14. Angular momentum conservation law in light-front quantum field theory

    NASA Astrophysics Data System (ADS)

    Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

    2017-03-01

    We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.

  15. Total angular momentum waves for scalar, vector, and tensor fields

    NASA Astrophysics Data System (ADS)

    Dai, Liang; Kamionkowski, Marc; Jeong, Donghui

    2012-12-01

    Most calculations in cosmological perturbation theory, including those dealing with the inflationary generation of perturbations, their time evolution, and their observational consequences, decompose those perturbations into plane waves (Fourier modes). However, for some calculations, particularly those involving observations performed on a spherical sky, a decomposition into waves of fixed total angular momentum (TAM) may be more appropriate. Here we introduce TAM waves—solutions of fixed total angular momentum to the Helmholtz equation—for three-dimensional scalar, vector, and tensor fields. The vector TAM waves of given total angular momentum can be decomposed further into a set of three basis functions of fixed orbital angular momentum, a set of fixed helicity, or a basis consisting of a longitudinal (L) and two transverse (E and B) TAM waves. The symmetric traceless rank-2 tensor TAM waves can be similarly decomposed into a basis of fixed orbital angular momentum or fixed helicity, or a basis that consists of a longitudinal (L), two vector (VE and VB, of opposite parity), and two tensor (TE and TB, of opposite parity) waves. We show how all of the vector and tensor TAM waves can be obtained by applying derivative operators to scalar TAM waves. This operator approach then allows one to decompose a vector field into three covariant scalar fields for the L, E, and B components and symmetric-traceless-tensor fields into five covariant scalar fields for the L, VE, VB, TE, and TB components. We provide projections of the vector and tensor TAM waves onto vector and tensor spherical harmonics. We provide calculational detail to facilitate the assimilation of this formalism into cosmological calculations. As an example, we calculate the power spectra of the deflection angle for gravitational lensing by density perturbations and by gravitational waves. We comment on an alternative approach to cosmic microwave background fluctuations based on TAM waves. An

  16. Fuel Fabrication for Surrogate Sphere-Pac Rodlet

    SciTech Connect

    Del Cul, G.D.

    2005-07-19

    Sphere-pac fuel consists of a blend of spheres of two or three different size fractions contained in a fuel rod. The smear density of the sphere-pac fuel column can be adjusted to the values obtained for light-water reactor (LWR) pellets (91-95%) by using three size fractions, and to values typical of the fast-reactor oxide fuel column ({approx}85%) by using two size fractions. For optimum binary packing, the diameters of the two sphere fractions must differ by at least a factor of 7 (ref. 3). Blending of spheres with smaller-diameter ratios results in difficult blending, nonuniform loading, and lower packing fractions. A mixture of about 70 vol% coarse spheres and 30 vol% fine spheres is needed to obtain high packing fractions. The limiting smear density for binary packing is 86%, with about 82% achieved in practice. Ternary packing provides greater smear densities, with theoretical values ranging from 93 to 95%. Sphere-pac technology was developed in the 1960-1990 period for thermal and fast spectrum reactors of nearly all types (U-Th and U-Pu fuel cycles, oxide and carbide fuels), but development of this technology was most strongly motivated by the need for remote fabrication in the thorium fuel cycle. The application to LWR fuels as part of the DOE Fuel Performance Improvement Program did not result in commercial deployment for a number of reasons, but the relatively low production cost of existing UO{sub 2} pellet fuel is probably the most important factor. In the case of transmutation fuels, however, sphere-pac technology has the potential to be a lower-cost alternative while also offering great flexibility in tailoring the fuel elements to match the exact requirements of any particular reactor core at any given time in the cycle. In fact, the blend of spheres can be adjusted to offer a different composition for each fuel pin or group of pins in a given fuel element. Moreover, it can even provide a vertical gradient of composition in a single fuel pin. For

  17. Development of PACS Digital Pump and implications for other industries

    NASA Astrophysics Data System (ADS)

    Banister, M.; Vohnout, S.; Kenman, D.

    2007-04-01

    This paper discusses the development and system integration of the Pulse Activated Cell System (PACS) Digital Pump technology using 2 types of electro-activated polymer (EAP) actuators. This is a platform specifically developed for the integration of sensor feedback loops to create an autonomous fluidic monitoring, reaction and delivery system. Initial, proof of concept, performance testing results are discussed as well as development for a medical drug delivery device and higher volume infusion therapy device. Uses and applications of the technology in other industries is considered as the PAC System provides a new ability to pump single or multiple fluid flows in a single pump that is programmable with the ability to vary direction, pressure and flow rates. The result is digital control of fluidic delivery, testing and mixing in application scaleable product packages. This technology will lead to new low cost yet sophisticated fluidic processing products and devices for many industries.

  18. Factors influencing perceived angular velocity

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary K.; Calderone, Jack B.

    1991-01-01

    Angular velocity perception is examined for rotations both in depth and in the image plane and the influence of several object properties on this motion parameter is explored. Two major object properties are considered, namely, texture density which determines the rate of edge transitions for rotations in depth, i.e., the number of texture elements that pass an object's boundary per unit of time, and object size which determines the tangential linear velocities and 2D image velocities of texture elements for a given angular velocity. Results of experiments show that edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities had an impact on perceived angular velocity; this bias was associated with 2D image velocity rather than 3D tangential velocity. Despite these biases judgements were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter appeared to be good for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

  19. Dicoogle - an open source peer-to-peer PACS.

    PubMed

    Costa, Carlos; Ferreira, Carlos; Bastião, Luís; Ribeiro, Luís; Silva, Augusto; Oliveira, José Luís

    2011-10-01

    Picture Archiving and Communication Systems (PACS) have been widely deployed in healthcare institutions, and they now constitute a normal commodity for practitioners. However, its installation, maintenance, and utilization are still a burden due to their heavy structures, typically supported by centralized computational solutions. In this paper, we present Dicoogle, a PACS archive supported by a document-based indexing system and by peer-to-peer (P2P) protocols. Replacing the traditional database storage (RDBMS) by a documental organization permits gathering and indexing data from file-based repositories, which allows searching the archive through free text queries. As a direct result of this strategy, more information can be extracted from medical imaging repositories, which clearly increases flexibility when compared with current query and retrieval DICOM services. The inclusion of P2P features allows PACS internetworking without the need for a central management framework. Moreover, Dicoogle is easy to install, manage, and use, and it maintains full interoperability with standard DICOM services.

  20. Comparison of case retrieval times: film versus PACS

    NASA Astrophysics Data System (ADS)

    Horii, Steven C.; Levine, Betty A.; Goger, Gregory; Mun, Seong K.; Fielding, Robert; Garra, Brian S.; Lo, Shih-Chung B.; Krasner, Brian; Benson, Harold R.

    1992-07-01

    One of the advantages which a picture archiving and communications system (PACS) is supposed to provide over film-based operation is improved performance in retrieving images. While is seems self-evident that this should be so, we wanted to verify this, and provide some time comparisons for the two methods. The experiment consisted of randomly selecting ultrasound (US) and computed tomography (CT) cases and determining how long it took to retrieve them at one of our PACS workstations, and to retrieve them in person from the film room. To simulate actual retrieval volumes, a total of 40 cases from current to six months old, 20 cases from the past year, and 10 cases over one year old, was selected. Results indicate that indeed, PACS retrieval can be faster than file room retrieval. However, the difference is less for recent cases than for older cases. For cases six or fewer months old, the workstation retrieval was about two and one-half minutes faster per case than the film file room. This time difference increased markedly when extended to the one year and over one year groups. This paper details the results of this study, and will also provide information about the reliability of the two archives.

  1. Regional maintenance approach for PACS within the healthcare enterprise

    NASA Astrophysics Data System (ADS)

    Staley, Steven D.; Romlein, John R.; Chacko, Anna K.; Radvany, Martin

    2000-05-01

    With the proliferation of Picture Archiving and Communications Systems (PACS) throughout the U.S. Healthcare System, there is an immense need for alternative approaches to maintenance support of PACS systems. One method of cost reduction is through the implementation of regional maintenance programs. While many PACS vendors are willing to negotiate various forms of shared service arrangements, multi-facility and regional negotiations are rarely implemented. This paper will present such an approach by describing a four step process: (1) Identify maintenance tasks across the entire region/enterprise; (2) Identify maintenance resources within the region/enterprise that can be assigned against those tasks; (3) Identify vendor unique resources that must be added to regional/enterprise resources to complete the required coverage of maintenance tasks; and (4) Negotiate with all member sites of the region/enterprise and the vendor for the assignment of resources against all maintenance tasks. Additionally, these steps will be balanced through identification of the principal tradeoffs tied to maintenance resourcing, namely: quality, speed and cost. If this approach is implemented, it presents a mechanism for achieving maintenance service cost reductions, while supporting clinical operations, through the benefits of economies of scale and collective bargaining.

  2. Hospital-integrated PACS at the University Hospital of Geneva

    NASA Astrophysics Data System (ADS)

    Ratib, Osman M.; Ligier, Yves; Hochstrasser, Denis; Scherrer, Jean-Raoul

    1991-07-01

    The PACS under development at the University Hospital of Geneva is a hospital-wide image management system for radiological as well as non-radiological medical images which is part of one of the widest hospital information systems (HIS) in Switzerland (Diogene system). It is based on a multi-vendor open architecture and a set of widely available industry standards, namely: Unix as the operating system, TCP-IP as network protocol and an SQL-based distributed database (INGRES) that handles both the PACS and the HIS. The PACS is based on a distributed architecture of servers of two types: the archive servers connected to the sources of images and equipped with large optical disk libraries (jukeboxes) and display servers distributed over the hospital. A standard image storage format was developed based on the ACR-NEMA standard. This file format (the PAPYRUS format) allows storage of sets of images as a sequence of ACR-NEMA messages in an 'encapsulated' file structure. In order to provide a more uniform user interface on a variety of different workstations, a common platform for image display and manipulation called OSIRIS is developed based on X-11 windowing system and OSF/Motif extension. Such a platform is designed to be portable to any computer running Unix and equipped with a graphic display system running X-11. Because this software is written in the object-oriented language C++, it is easily expandable and easily adaptable to different needs and requirements.

  3. NASA Spacecraft Sees 'Pac-Man' on Saturn Moon

    NASA Image and Video Library

    2017-09-27

    NASA release date March 29, 2010 The highest-resolution-yet temperature map and images of Saturn’s icy moon Mimas obtained by NASA’s Cassini spacecraft reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble “Pac-Man” eating a dot, and striking bands of light and dark in crater walls. The left portion of this image shows Mimas in visible light, an image that has drawn comparisons to the "Star Wars" Death Star. The right portion shows the new temperature map, which resembles 1980s video game icon "Pac Man." To learn more about this image go to: www.nasa.gov/centers/goddard/news/features/2010/pac-man-m... Credit: NASA/JPL/Goddard/SWRI/SSI NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

  4. Protecting clinical data in PACS, teleradiology systems, and research environments

    NASA Astrophysics Data System (ADS)

    Meissner, Marion C.; Collmann, Jeff R.; Tohme, Walid G.; Mun, Seong K.

    1997-05-01

    As clinical data is more widely stored in electronic patient record management systems and transmitted over the Internet and telephone lines, it becomes more accessible and therefore more useful, but also more vulnerable. Computer systems such as PACS, telemedicine applications, and medical research networks must protect against accidental or deliberate modification, disclosure, and violation of patient confidentiality in order to be viable. Conventional wisdom in the medical field and among lawmakers legislating the use of electronic medical records suggests that, although it may improve access to information, an electronic medical record cannot be as secure as a traditional paper record. This is not the case. Information security is a well-developed field in the computer and communications industry. If medical information systems, such as PACS, telemedicine applications, and research networks, properly apply information security techniques, they can ensure the accuracy and confidentiality of their patient information and even improve the security of their data over a traditional paper record. This paper will elaborate on some of these techniques and discuss how they can be applied to medical information systems. The following systems will be used as examples for the analysis: a research laboratory at Georgetown University Medical Center, the Deployable Radiology system installed to support the US Army's peace- keeping operation in Bosnia, a kidney dialysis telemedicine system in Washington, D.C., and various experiences with implementing and integrating PACS.

  5. Integration of implant planning workflows into the PACS infrastructure

    NASA Astrophysics Data System (ADS)

    Gessat, Michael; Strauß, Gero; Burgert, Oliver

    2008-03-01

    The integration of imaging devices, diagnostic workstations, and image servers into Picture Archiving and Communication Systems (PACS) has had an enormous effect on the efficiency of radiology workflows. The standardization of the information exchange between the devices with the DICOM standard has been an essential precondition for that development. For surgical procedures, no such infrastructure exists. With the increasingly important role computerized planning and assistance systems play in the surgical domain, an infrastructure that unifies the communication between devices becomes necessary. In recent publications, the need for a modularized system design has been established. A reference architecture for a Therapy Imaging and Model Management System (TIMMS) has been proposed. It was accepted by the DICOM Working Group 6 as the reference architecture for DICOM developments for surgery. In this paper we propose the inclusion of implant planning systems into the PACS infrastructure. We propose a generic information model for the patient specific selection and positioning of implants from a repository according to patient image data. The information models are based on clinical workflows from ENT, cardiac, and orthopedic surgery as well as technical requirements derived from different use cases and systems. We show an exemplary implementation of the model for application in ENT surgery: the selection and positioning of an ossicular implant in the middle ear. An implant repository is stored in the PACS. It makes use of an experimental implementation of the Surface Mesh Module that is currently being developed as extension to the DICOM standard.

  6. Application of usability testing for improving PACS workstation design

    NASA Astrophysics Data System (ADS)

    Erickson, Bradley J.; Kossack, Merrick F.

    2000-05-01

    User-centered design is a critical step in the product development cycle. It is an iterative process consisting of product design, implementation, and evaluation stages. Industry-standard usability metrics were employed to evaluate two sequential versions of commercial Picture Archiving and Communications System (PACS) workstation software as part of this process. They were evaluated 6 months apart by five radiologists with varying PACS experience. All radiologists were naive to the specific workstation tested. After a brief workstation overview, they were videotaped as they completed scenarios that closely simulated typical radiological practice. Each scenario consisted of various task categories. The task duration, nature and number of errors, help requests, and operator's manual consultations were recorded. After evaluating the first software version, areas for improvement were identified and the application design modified. An unexpected result was the rewriting of the software manual to be task- and process-based rather than feature-based. Testing of the second version revealed a 22% improvement in performance time and 30% decrease in the number of errors compared to the first. Usability testing objectively identifies areas for improvement in the PACS workstation software. Additionally, it provides quantitative measures that may be used to prioritize and suggest future design efforts. Performing this evaluation as early as possible results in the rapid evolution of an application that will maximize radiologists' productivity and satisfaction.

  7. Twisting perturbed parafermions

    NASA Astrophysics Data System (ADS)

    Belitsky, A. V.

    2017-07-01

    The near-collinear expansion of scattering amplitudes in maximally supersymmetric Yang-Mills theory at strong coupling is governed by the dynamics of stings propagating on the five sphere. The pentagon transitions in the operator product expansion which systematize the series get reformulated in terms of matrix elements of branch-point twist operators in the two-dimensional O(6) nonlinear sigma model. The facts that the latter is an asymptotically free field theory and that there exists no local realization of twist fields prevents one from explicit calculation of their scaling dimensions and operator product expansion coefficients. This complication is bypassed making use of the equivalence of the sigma model to the infinite-level limit of WZNW models perturbed by current-current interactions, such that one can use conformal symmetry and conformal perturbation theory for systematic calculations. Presently, to set up the formalism, we consider the O(3) sigma model which is reformulated as perturbed parafermions.

  8. Vortex perturbation dynamics

    NASA Technical Reports Server (NTRS)

    Criminale, W. O.; Lasseigne, D. G.; Jackson, T. L.

    1995-01-01

    An initial value approach is used to examine the dynamics of perturbations introduced into a vortex under strain. Both the basic vortex considered and the perturbations are taken as fully three-dimensional. An explicit solution for the time evolution of the vorticity perturbations is given for arbitrary initial vorticity. Analytical solutions for the resulting velocity components are found when the initial vorticity is assumed to be localized. For more general initial vorticity distributions, the velocity components are determined numerically. It is found that the variation in the radial direction of the initial vorticity disturbance is the most important factor influencing the qualitative behavior of the solutions. Transient growth in the magnitude of the velocity components is found to be directly attributable to the compactness of the initial vorticity.

  9. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S. E-mail: hipolito@ceunes.ufes.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  10. Characterization and coagulation of a polyaluminum chloride (PAC) coagulant with high Al13 content.

    PubMed

    Gao, Bao-Yu; Chu, Yong-Bao; Yue, Qin-Yan; Wang, Bing-Jian; Wang, Shu-Guang

    2005-07-01

    A polyaluminum chloride (PAC) coagulant was prepared from AlCl3 x 6H2O and Na2CO3. The Al13 species in PAC was separated and purified by the SO4(2-)/Ba2+ deposition-replacement method, and characterized by 27Al-NMR and XRD. From 27Al-NMR spectroscopy, it was found that PAC obtained after separation and purification contained more Al13 (PAC-Al13, for short) than original PAC before separation and purification. In XRD spectra, a strong Al13 signal appeared in the range of 2theta from 5 to 25 degrees. Jar tests were performed to test the coagulation efficiency of AlCl3, PAC and PAC-Al13 in treating synthetic or actual water samples. Compared with PAC and AlCl3, PAC-Al13 gives the best results for turbidity, humic acid and color removal, and achieves the highest charge-neutralizing ability. Under the study conditions, PAC-Al13 gave about 90% humic acid removal and almost 100% reactive blue dye removal when its dosages were 4.0 and 15 mg/L as Al, respectively. The Al13 species has a higher positive charge and is the most effective polymeric Al species in water and wastewater treatment.

  11. Development Of A PACS System At The University Hospital In Brussels, Belgium .

    NASA Astrophysics Data System (ADS)

    Deconinck, F.; Duerinckx, A. J.; Kuijk, S.; Nyssen, M.; Tombeur, D.

    1986-06-01

    A prototype PACS system is being designed which will connect an existing nuclear medicine mini NM-PACS with an imaging facility in the medical school, a PET and experimental medical imaging facility, and research imaging facilities in the Radiology and Nuclear Medicine Department of the Free University in Brussels ( VUB, Jette), Belgium. The local nuclear medicine NM-PACS uses SOPHA (Informatek) equipment with parallel DMA connections. The PET and experimental medical imaging facility is based on Apollo workstations. The medical school imaging network connects a VAX 11/785, a VICOM and several other computers, and is physically located next to the hospital. A local radiology Rad-PACS will be based on an Ethernet link. The "global PACS" described in this paper will connect all image processing facilities. Initially, 4 Apollo workstations with a token passing ring network (12 Mbit/sec), a 500 Mbyte storage, and 1kx1k displays will be used. The following subparts of the "global PACS" are novel: a pictorial-menu driven user-interface software for image display, processing and management is being developed to facilitate the use of the PACS hardware . The image data base is distributed over the different areas of the hospital and university. The system will also provide the distributed computing power (parallel processing and acquisition of images) needed for a new HIDAC PET camera being constructed at the university. This PACS project is part of a large scale European effort (EuroPacs) to develop PACS technology.

  12. Variations in atmospheric angular momentum

    NASA Technical Reports Server (NTRS)

    Rosen, R. D.; Salstein, D. A.

    1981-01-01

    Twice-daily values of the atmosphere's angular momentum about the polar axis during the five years from 1976 through 1980 are presented in graphs and a table. The compilation is based on a global data set, incorporating 90 percent of the mass of the atmosphere. The relationship between changes in the angular momentum of the atmosphere and changes in the length of day is described, as are the main sources of error in the data. The variability in angular momentum is revealed in a preliminary fashion by means of a spectral decomposition. The data presented should stimulate comparisons with other measures of the length of day and so provide a basis for greater understanding of Earth-atmosphere interactions.

  13. Interferometric measurement of angular motion

    NASA Astrophysics Data System (ADS)

    Peña Arellano, Fabián Erasmo; Panjwani, Hasnain; Carbone, Ludovico; Speake, Clive C.

    2013-04-01

    This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10-11 rad/sqrt{textrm {Hz}} from audioband down to 100 mHz and an angular measurement range of more than ±1°.

  14. Perturbed nonlinear differential equations

    NASA Technical Reports Server (NTRS)

    Proctor, T. G.

    1972-01-01

    The existence of a solution defined for all t and possessing a type of boundedness property is established for the perturbed nonlinear system y = f(t,y) + F(t,y). The unperturbed system x = f(t,x) has a dichotomy in which some solutions exist and are well behaved as t increases to infinity, and some solution exists and are well behaved as t decreases to minus infinity. A similar study is made for a perturbed nonlinear differential equation defined on a half line, R+, and the existence of a family of solutions with special boundedness properties is established. The ideas are applied to integral manifolds.

  15. HIS/RIS/PACS integration: getting to the gold standard.

    PubMed

    Boochever, Stephen S

    2004-01-01

    The technology for acquiring, storing, retrieving, displaying, and distributing images has advanced dramatically in recent years. The push is toward enterprise-wide image management solutions, where digital images from radiology, cardiology, and other "ologies" are seamlessly linked with information from clinical information systems and other databases, and they are accessed seamlessly from a single point of end-user interaction. The "gold standard" of system integration would provide the platform for improved workflow, patient throughput and patient safety, as well as decreased cost. Unfortunately, the gold standard remains elusive in most healthcare environments, even those with new systems. One of the earliest issues that plagued the progress of hospital information system/radiology information systems/picture archiving and communication systems (HIS/RIS/PACS) integration was a matter of language between Health Level-7 (HL7) and DICOM. This barrier was solved by the broker--a software and hardware device that accepts HL7 messages from the RIS then translates, or maps, the data to produce DICOM messages for transmission to the PACS. Technologist workflow requires patient and exam information from the RIS to flow to the modality. The broker provides support for this by taking advantage of the DICOM Modality Worklist (DMWL). Two primary problems are inherent in most brokered configurations. Workflow is driven by paper, and RIS information flows in 1 direction only, which leads to duplicative databases. Overcoming the limitations of HIS/RIS/PACS connectivity requires industry accepted communication protocols/rules. To facilitate this, the Integrating the Health Care Enterprise (IHE) initiative was developed. The goal of IHE is to provide end-users improved access to critical patient and clinical information across all systems within the healthcare delivery network. While the IHE initiative began to facilitate more efficient, predictable, and functional integration

  16. Non-Colinearity of Angular Velocity and Angular Momentum

    ERIC Educational Resources Information Center

    Burr, A. F.

    1974-01-01

    Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

  17. Non-Colinearity of Angular Velocity and Angular Momentum

    ERIC Educational Resources Information Center

    Burr, A. F.

    1974-01-01

    Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

  18. Angular Limb Deformities: Growth Retardation.

    PubMed

    McCarrel, Taralyn M

    2017-08-01

    Angular limb deformities are common in foals; however, the importance of the deformity and if treatment is required depend on the degree of deformity relative to normal conformation for stage of growth, the breed and discipline expectations, age, and response to conservative therapies. This article addresses the importance of the foal conformation examination to determine which foals need surgical intervention to correct an angular deformity and when. Techniques for surgical growth retardation include the transphyseal staple, screw and wire transphyseal bridge, and transphyseal screw. Appropriate timing for intervention for each location and complications associated with each procedure are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Solar cell angular position transducer

    NASA Technical Reports Server (NTRS)

    Sandford, M. C.; Gray, D. L. (Inventor)

    1980-01-01

    An angular position transducer utilizing photocells and a light source is disclosed. The device uses a fully rotatable baffle which is connected via an actuator shaft to the body whose rotational displacement is to be measured. The baffle blocks the light path between the light source and the photocells so that a constant semicircular beam of light reaches the photocells. The current produced by the photocells is fed through a resistor, a differential amplifier measures the voltage drop across the resistor which indicates the angular position of the actuator shaft and hence of the object.

  20. Automated Angular Momentum Recoupling Algebra

    NASA Astrophysics Data System (ADS)

    Williams, H. T.; Silbar, Richard R.

    1992-04-01

    We present a set of heuristic rules for algebraic solution of angular momentum recoupling problems. The general problem reduces to that of finding an optimal path from one binary tree (representing the angular momentum coupling scheme for the reduced matrix element) to another (representing the sub-integrals and spin sums to be done). The method lends itself to implementation on a microcomputer, and we have developed such an implementation using a dialect of LISP. We describe both how our code, called RACAH, works and how it appears to the user. We illustrate the use of RACAH for several transition and scattering amplitude matrix elements occurring in atomic, nuclear, and particle physics.

  1. Resilience of hybrid optical angular momentum qubits to turbulence

    NASA Astrophysics Data System (ADS)

    Farías, Osvaldo Jiménez; D'Ambrosio, Vincenzo; Taballione, Caterina; Bisesto, Fabrizio; Slussarenko, Sergei; Aolita, Leandro; Marrucci, Lorenzo; Walborn, Stephen P.; Sciarrino, Fabio

    2015-02-01

    Recent schemes to encode quantum information into the total angular momentum of light, defining rotation-invariant hybrid qubits composed of the polarization and orbital angular momentum degrees of freedom, present interesting applications for quantum information technology. However, there remains the question as to how detrimental effects such as random spatial perturbations affect these encodings. Here, we demonstrate that alignment-free quantum communication through a turbulent channel based on hybrid qubits can be achieved with unit transmission fidelity. In our experiment, alignment-free qubits are produced with q-plates and sent through a homemade turbulence chamber. The decoding procedure, also realized with q-plates, relies on both degrees of freedom and renders an intrinsic error-filtering mechanism that maps errors into losses.

  2. Resilience of hybrid optical angular momentum qubits to turbulence.

    PubMed

    Farías, Osvaldo Jiménez; D'Ambrosio, Vincenzo; Taballione, Caterina; Bisesto, Fabrizio; Slussarenko, Sergei; Aolita, Leandro; Marrucci, Lorenzo; Walborn, Stephen P; Sciarrino, Fabio

    2015-02-12

    Recent schemes to encode quantum information into the total angular momentum of light, defining rotation-invariant hybrid qubits composed of the polarization and orbital angular momentum degrees of freedom, present interesting applications for quantum information technology. However, there remains the question as to how detrimental effects such as random spatial perturbations affect these encodings. Here, we demonstrate that alignment-free quantum communication through a turbulent channel based on hybrid qubits can be achieved with unit transmission fidelity. In our experiment, alignment-free qubits are produced with q-plates and sent through a homemade turbulence chamber. The decoding procedure, also realized with q-plates, relies on both degrees of freedom and renders an intrinsic error-filtering mechanism that maps errors into losses.

  3. Even perturbations of the self-similar Vaidya space-time

    SciTech Connect

    Nolan, Brien C.; Waters, Thomas J.

    2005-05-15

    We study even parity metric and matter perturbations of all angular modes in self-similar Vaidya space-time. We focus on the case where the background contains a naked singularity. Initial conditions are imposed, describing a finite perturbation emerging from the portion of flat space-time preceding the matter-filled region of space-time. The most general perturbation satisfying the initial conditions is allowed to impinge upon the Cauchy horizon (CH), where the perturbation remains finite: There is no 'blue-sheet' instability. However, when the perturbation evolves through the CH and onto the second future similarity horizon of the naked singularity, divergence necessarily occurs: This surface is found to be unstable. The analysis is based on the study of individual modes following a Mellin transform of the perturbation. We present an argument that the full perturbation remains finite after resummation of the (possibly infinite number of) modes.

  4. Singular perturbation analysis of a reduced model for collective motion: a renormalization group approach.

    PubMed

    Lee, Chiu Fan

    2011-03-01

    In a system of noisy self-propelled particles with interactions that favor directional alignment, collective motion will appear if the density of particles is beyond a critical density. Starting with a reduced model for collective motion, we determine how the critical density depends on the form of the initial perturbation. Specifically, we employ a renormalization-group improved perturbative method to analyze the model equations and show analytically, up to first order in the perturbation parameter, how the critical density is modified by the strength of the initial angular perturbation in the system.

  5. Comparison of PAC and QTH light sources on polymerization of resin composites.

    PubMed

    Katahira, Nobuhiro; Foxton, Richard M; Inai, Norimichi; Otsuki, Masayuki; Tagami, Junji

    2004-04-01

    To evaluate the polymerization shrinkage, Knoop hardness number (KHN) and compressive strength and to suggest a suitable time for irradiating resin composite restorations, when using a high-intensity light source. Two restorative resin composites, UniFil F, and Clearfil AP-X were employed. A high-intensity light unit (more than 1000mW/cm2) with a xenon discharge lamp (Apollo 95E), which is generally called a plasma arc light-curing unit (PAC), was compared with a conventional light-curing unit fitted with a quartz-tungsten-halogen lamp (QTH) (GC Newlight VL2). The resin composites were exposed to the light in four ways. For QTH, the irradiation time was for 40 seconds (QTH 40 seconds). For PAC, 3 seconds (PAC 3 seconds), 3+3 seconds (PAC 3+3 seconds) and 3+3+3 seconds (PAC 3+3+3 seconds) was used. Polymerization shrinkage using the bonded disk technique developed by Watts, Knoop hardness number (KHN), and compressive strength were then determined. Two-way ANOVA revealed that the two materials for PAC 3+3 seconds and PAC 3+3+3 seconds made no difference in polymerization shrinkage compared to QTH 40 seconds (P < 0.001). The polymerization shrinkage of the materials cured by PAC for 3 seconds was significantly lower than those cured by QTH for 40 seconds in a range from 61% to 72%, by the PAC for 3 + 3 seconds in a range from 65% to 88%, and those by PAC 3+3+3 seconds in a range of 61% to 72% (P < 0.001). With regard to microhardness, the composites in PAC 3+3+3 seconds exposure made no difference in hardness compared with QTH 40 seconds (P < 0.001). PAC 3+3 seconds exposure gave hardness at less than 3.0 mm depth equivalent to that of the QTH 40 seconds. PAC 3 seconds at 2.0 mm depth produced inferior hardness compared with the QTH 40 seconds. The compressive strength for the PAC 3 seconds exposure was significantly lower than that of PAC 3+3 seconds, PAC 3+3+3 seconds and QTH 40 seconds for each material. Irradiation by the high-intensity light source for 3 seconds

  6. Perturbing turbulence beyond collapse

    NASA Astrophysics Data System (ADS)

    Kühnen, Jakob; Scarselli, Davide; Hof, Björn; Nonlinear Dynamics; Turbulence Group Team

    2016-11-01

    Wall-bounded turbulent flows are considered to be in principle stable against perturbations and persist as long as the Reynolds number is sufficiently high. We show for the example of pipe flow that a specific perturbation of the turbulent flow field disrupts the genesis of new turbulence at the wall. This leads to an immediate collapse of the turbulent flow and causes complete relaminarisation further downstream. The annihilation of turbulence is effected by a steady manipulation of the streamwise velocity component only, greatly simplifying control efforts which usually require knowledge of the highly complex three dimensional and time dependent velocity fields. We present several different control schemes from laboratory experiments which achieve the required perturbation of the flow for total relaminarisation. Transient growth, a linear amplification mechanism measuring the efficiency of eddies in redistributing shear that quantifies the maximum perturbation energy amplification achievable over a finite time in a linearized framework, is shown to set a clear-cut threshold below which turbulence is impeded in its formation and thus permanently annihilated.

  7. Cosmological perturbations in antigravity

    NASA Astrophysics Data System (ADS)

    Oltean, Marius; Brandenberger, Robert

    2014-10-01

    We compute the evolution of cosmological perturbations in a recently proposed Weyl-symmetric theory of two scalar fields with oppositely signed conformal couplings to Einstein gravity. It is motivated from the minimal conformal extension of the standard model, such that one of these scalar fields is the Higgs while the other is a new particle, the dilaton, introduced to make the Higgs mass conformally symmetric. At the background level, the theory admits novel geodesically complete cyclic cosmological solutions characterized by a brief period of repulsive gravity, or "antigravity," during each successive transition from a big crunch to a big bang. For simplicity, we consider scalar perturbations in the absence of anisotropies, with potential set to zero and without any radiation. We show that despite the necessarily wrong-signed kinetic term of the dilaton in the full action, these perturbations are neither ghostlike nor tachyonic in the limit of strongly repulsive gravity. On this basis, we argue—pending a future analysis of vector and tensor perturbations—that, with respect to perturbative stability, the cosmological solutions of this theory are viable.

  8. A WEB-based telePACS using an asymmetric satellite system.

    PubMed

    Hwang, S C; Lee, M H

    2000-09-01

    We have developed a WWW-based TelePACS that can access every permitted PACS server via the Internet. Java programming techniques were used to implement the system, which can access and retrieve medical information and images through Web browsers only such as Netscape without specific tools. We also have developed a consolidator that performs as a manager to connect a conventional PACS server to a Web-based TelePACS server. We have developed the Asymmetric Satellite Data Communication System (ASDCS) as a fast communication system. The ASDCS uses a receive-only satellite link for data delivery and a terrestrial network for control communication. In conclusion, we were able to develop a cost-effective and fast PACS using Web technology. Web technology expanded the scope of use for a dedicated PACS from intrahospital to public use.

  9. Treatment of coal gasification wastewater by membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system.

    PubMed

    Jia, Shengyong; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Fang, Fang; Zhao, Qian

    2014-12-01

    A laboratory-scale membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system was developed to treat coal gasification wastewater to enhance the COD, total phenols (TPh), NH4+ removals and migrate the membrane fouling. Since the MBR–PAC system operated with PAC dosage of 4 g L−1, the maximum removal efficiencies of COD, TPh and NH4+ reached 93%, 99% and 63%, respectively with the corresponding influent concentrations of 2.27 g L−1, 497 mg L−1 and 164 mg N L−1; the PAC extraction efficiencies of COD, TPh and NH4+ were 6%, 3% and 13%, respectively; the transmembrane pressure decreased 34% with PAC after 50 d operation. The results demonstrate that PAC played a key role in the enhancement of biodegradability and mitigation of membrane fouling.

  10. Controlling the spins angular momentum in ferromagnets with sequences of picosecond acoustic pulses.

    PubMed

    Kim, Ji-Wan; Vomir, Mircea; Bigot, Jean-Yves

    2015-02-17

    Controlling the angular momentum of spins with very short external perturbations is a key issue in modern magnetism. For example it allows manipulating the magnetization for recording purposes or for inducing high frequency spin torque oscillations. Towards that purpose it is essential to modify and control the angular momentum of the magnetization which precesses around the resultant effective magnetic field. That can be achieved with very short external magnetic field pulses or using intrinsically coupled magnetic structures, resulting in a transfer of spin torque. Here we show that using picosecond acoustic pulses is a versatile and efficient way of controlling the spin angular momentum in ferromagnets. Two or three acoustic pulses, generated by femtosecond laser pulses, allow suppressing or enhancing the magnetic precession at any arbitrary time by precisely controlling the delays and amplitudes of the optical pulses. A formal analogy with a two dimensional pendulum allows us explaining the complex trajectory of the magnetic vector perturbed by the acoustic pulses.

  11. Angular Dynamics of a Small Particle in Turbulence.

    PubMed

    Candelier, F; Einarsson, J; Mehlig, B

    2016-11-11

    We compute the angular dynamics of a neutrally buoyant nearly spherical particle immersed in an unsteady fluid. We assume that the particle is small, that its translational slip velocity is negligible, and that unsteady and convective inertia are small perturbations. We derive an approximation for the torque on the particle that determines the first inertial corrections to Jeffery's equation. These corrections arise as a consequence of local vortex stretching and can be substantial in turbulence, where local vortex stretching is strong and closely linked to the irreversibility of turbulence.

  12. Angular structure of lacunarity, and the renormalization group

    PubMed

    Ball; Caldarelli; Flammini

    2000-12-11

    We formulate the angular structure of lacunarity in fractals, in terms of a symmetry reduction of the three point correlation function. This provides a rich probe of universality, and first measurements yield new evidence in support of the equivalence between self-avoiding walks (SAW's) and percolation perimeters in two dimensions. We argue that the lacunarity reveals much of the renormalization group in real space. This is supported by exact calculations for random walks and measured data for percolation clusters and SAW's. Relationships follow between exponents governing inward and outward propagating perturbations, and we also find a very general test for the contribution of long-range interactions.

  13. High angular resolution at LBT

    NASA Astrophysics Data System (ADS)

    Conrad, A.; Arcidiacono, C.; Bertero, M.; Boccacci, P.; Davies, A. G.; Defrere, D.; de Kleer, K.; De Pater, I.; Hinz, P.; Hofmann, K. H.; La Camera, A.; Leisenring, J.; Kürster, M.; Rathbun, J. A.; Schertl, D.; Skemer, A.; Skrutskie, M.; Spencer, J. R.; Veillet, C.; Weigelt, G.; Woodward, C. E.

    2015-12-01

    High angular resolution from ground-based observatories stands as a key technology for advancing planetary science. In the window between the angular resolution achievable with 8-10 meter class telescopes, and the 23-to-40 meter giants of the future, LBT provides a glimpse of what the next generation of instruments providing higher angular resolution will provide. We present first ever resolved images of an Io eruption site taken from the ground, images of Io's Loki Patera taken with Fizeau imaging at the 22.8 meter LBT [Conrad, et al., AJ, 2015]. We will also present preliminary analysis of two data sets acquired during the 2015 opposition: L-band fringes at Kurdalagon and an occultation of Loki and Pele by Europa (see figure). The light curves from this occultation will yield an order of magnitude improvement in spatial resolution along the path of ingress and egress. We will conclude by providing an overview of the overall benefit of recent and future advances in angular resolution for planetary science.

  14. Noncontact measurement of angular deflection

    NASA Technical Reports Server (NTRS)

    Bryant, E. L.

    1978-01-01

    Technique for measuring instantaneous angular deflection of object requires no physical contact. Technique utilizes two flat refractors, converging lens, and different photocell. Distinction of method is its combination of optical and electromechanical components into feedback system in which measurement error is made to approach zero. Application is foreseen in measurement of torsional strain.

  15. Gas Accretion and Angular Momentum

    NASA Astrophysics Data System (ADS)

    Stewart, Kyle R.

    In this chapter, we review the role of gas accretion to the acquisition of angular momentum, both in galaxies and in their gaseous halos. We begin by discussing angular momentum in dark matter halos, with a brief review of tidal torque theory and the importance of mergers, followed by a discussion of the canonical picture of galaxy formation within this framework, where halo gas is presumed to shock-eat to the virial temperature of the halo, following the same spin distribution as the dark matter halo before cooling to the center of the halo to form a galaxy there. In the context of recent observational evidence demonstrating the presence of high angular momentum gas in galaxy halos, we review recent cosmological hydrodynamic simulations that have begun to emphasize the role of "cold flow" accretion—anisotropic gas accretion along cosmic filaments that does not shock-heat before sinking to the central galaxy. We discuss the implications of these simulations, reviewing a number of recent developments in the literature, and suggest a revision to the canonical model as it relates to the expected angular momentum content of gaseous halos around galaxies.

  16. Olympic Wrestling and Angular Momentum.

    ERIC Educational Resources Information Center

    Carle, Mark

    1988-01-01

    Reported is the use of a wrestling photograph in a noncalculus introductory physics course. The photograph presents a maneuver that could serve as an example for a discussion on equilibrium, forces, torque, and angular motion. Provided are some qualitative thoughts as well as quantitative calculations. (YP)

  17. Energy and angular momentum transfer in binary galaxies

    NASA Technical Reports Server (NTRS)

    Namboodiri, P. M. S.; Kochhar, R. K.

    1990-01-01

    The authors numerically studied tidal effects of a massive perturber on a satellite galaxy. The model consists of a spherical satellite galaxy and a point mass perturber and the encounter is non-penetrating. A wide range of density ratios and eccentricities of the relative orbits have been considered. The disruption of the satellite galaxy has been observed when the numerical value of the fractional change in the energy is greater than two. The changes in the energy and angular momentum show smooth variation in the case of unbound orbits and irregular variation in the bound orbit cases. It is shown that for a constant pericentral distance, increasing the density ratio decreases the tidal effects; and for a given density ratio an increase in the eccentricity decreases the tidal effects.

  18. A new approach to the propagation of light-like signals in perturbed cosmological backgrounds

    SciTech Connect

    Fanizza, G.; Gasperini, M.; Marozzi, G.; Veneziano, G. E-mail: gasperini@ba.infn.it E-mail: Gabriele.Veneziano@cern.ch

    2015-08-01

    We present a new method to compute the deflection of light rays in a perturbed FLRW geometry. We exploit the properties of the Geodesic Light Cone (GLC) gauge where null rays propagate at constant angular coordinates irrespectively of the given (inhomogeneous and/or anisotropic) geometry. The gravitational deflection of null geodesics can then be obtained, in any other gauge, simply by expressing the angular coordinates of the given gauge in terms of the GLC angular coordinates. We apply this method to the standard Poisson gauge, including scalar perturbations, and give the full result for the deflection effect in terms of the direction of observation and observed redshift up to second order, and up to third order for the leading lensing terms. We also compare our results with those presently available in the literature and, in particular, we provide a new non trivial check of a previous result on the luminosity-redshift relation up to second order in cosmological perturbation theory.

  19. Process development and fabrication for sphere-pac fuel rods. [PWR; BWR

    SciTech Connect

    Welty, R.K.; Campbell, M.H.

    1981-06-01

    Uranium fuel rods containing sphere-pac fuel have been fabricated for in-reactor tests and demonstrations. A process for the development, qualification, and fabrication of acceptable sphere-pac fuel rods is described. Special equipment to control fuel contamination with moisture or air and the equipment layout needed for rod fabrication is described and tests for assuring the uniformity of the fuel column are discussed. Fuel retainers required for sphere-pac fuel column stability and instrumentation to measure fuel column smear density are described. Results of sphere-pac fuel rod fabrication campaigns are reviewed and recommended improvements for high throughput production are noted.

  20. Functional transplant of photoactivated adenylyl cyclase (PAC) into Aplysia sensory neurons.

    PubMed

    Nagahama, Tatsumi; Suzuki, Takeshi; Yoshikawa, Shinya; Iseki, Mineo

    2007-09-01

    In neural mechanisms of animal learning, intracellular cAMP has been known to play an important role. In the present experiments we attempted functional transplant of a photoactivated adenylyl cyclase (PAC) isolated from Euglena into Aplysia neurons, and explored whether PAC can produce cAMP in the neurons by light stimulation. Serotonergic modulation of mechanoafferent sensory neurons in Aplysia pleural ganglia has been reported to increase intracellular cAMP level and promotes synaptic transmission to motor neurons by increasing spike width of sensory neurons. When cAMP was directly injected into the sensory neurons, spike amplitude temporarily decreased while spike width temporarily increased. This effect was not substituted by injection of 5'AMP, and maintained longer in a bath solution containing IBMX, the phosphodiesterase inhibitor. We, therefore, explored these changes as indicators of appearance of the PAC function. PAC or the PAC expression vector (pNEX-PAC) was injected into cell bodies of sensory neurons. Spike amplitude decreased in both cases and spike width increased in the PAC injection when the neurons were stimulated with light, suggesting that the transplanted PAC works well in Aplysia neurons. These results indicate that we can control cAMP production in specific neurons with light by the functional transplant of PAC.

  1. Parallel synthesis and biological evaluation of 837 analogues of procaspase-activating compound 1 (PAC-1).

    PubMed

    Hsu, Danny C; Roth, Howard S; West, Diana C; Botham, Rachel C; Novotny, Chris J; Schmid, Steven C; Hergenrother, Paul J

    2012-01-09

    Procaspase-Activating Compound 1 (PAC-1) is an ortho-hydroxy N-acyl hydrazone that enhances the enzymatic activity of procaspase-3 in vitro and induces apoptosis in cancer cells. An analogue of PAC-1, called S-PAC-1, was evaluated in a veterinary clinical trial in pet dogs with lymphoma and found to have considerable potential as an anticancer agent. With the goal of identifying more potent compounds in this promising class of experimental therapeutics, a combinatorial library based on PAC-1 was created, and the compounds were evaluated for their ability to induce death of cancer cells in culture. For library construction, 31 hydrazides were condensed in parallel with 27 aldehydes to create 837 PAC-1 analogues, with an average purity of 91%. The compounds were evaluated for their ability to induce apoptosis in cancer cells, and through this work, six compounds were discovered to be substantially more potent than PAC-1 and S-PAC-1. These six hits were further evaluated for their ability to relieve zinc-mediated inhibition of procaspase-3 in vitro. In general, the newly identified hit compounds are two- to four-fold more potent than PAC-1 and S-PAC-1 in cell culture, and thus have promise as experimental therapeutics for treatment of the many cancers that have elevated expression levels of procaspase-3.

  2. Educational RIS/PACS simulator integrated with the HIPAA compliant auditing (HCA) toolkit

    NASA Astrophysics Data System (ADS)

    Zhou, Zheng; Liu, Brent J.; Huang, H. K.; Zhang, J.

    2005-04-01

    Health Insurance Portability and Accountability Act (HIPAA), a guideline for healthcare privacy and security, has been officially instituted recently. HIPAA mandates healthcare providers to follow its privacy and security rules, one of which is to have the ability to generate audit trails on the data access for any specific patient on demand. Although most current medical imaging systems such as PACS utilize logs to record their activities, there is a lack of formal methodology to interpret these large volumes of log data and generate HIPAA compliant auditing trails. In this paper, we present a HIPAA compliant auditing (HCA) toolkit for auditing the image data flow of PACS. The toolkit can extract pertinent auditing information from the logs of various PACS components and store the information in a centralized auditing database. The HIPAA compliant audit trails can be generated based on the database, which can also be utilized for data analysis to facilitate the dynamic monitoring of the data flow of PACS. In order to demonstrate the HCA toolkit in a PACS environment, it was integrated with the PACS Simulator, that was presented as an educational tool in 2003 and 2004 SPIE. With the integration of the HCA toolkit with the PACS simulator, users can learn HIPAA audit concepts and how to generate audit trails of image data access in PACS, as well as trace the image data flow of PACS Simulator through the toolkit.

  3. Evaluation of medical student experience using medical student created StudentPACS flash based PACS simulator tutorials for learning radiological topics.

    PubMed

    Soman, Salil; Amorosa, Judith K; Mueller, Luke; Hu, Jun; Zou, Lily; Masand, Anjali; Cheng, Christina; Virk, Jaskirat; Rama, Hemesh; Tseng, Ian; Patel, Keyur; Connolly, Sarah E

    2010-06-01

    With studies regularly containing hundreds of images, the authors believe that the ability to efficiently review numerous images and identify findings is an important skill to teach medical students. Using the StudentPACS Adobe Flash extension, created within their department, the authors created StudentPACS modules that provide users with a virtual picture archiving and communication system environment, in which findings can be selected by mouse, triggering questions with referenced answers. The aim was to assess medical students' impressions of how learning from these modules compared to their personal experiences learning radiology from textbooks or static images. StudentPACS modules were created by medical students on elective under the supervision of resident and attending radiologists. MS I to IV students were then asked to complete StudentPACS modules that tied in with their current coursework, followed by an anonymous survey. Approximately 293 students participated. The majority of students reported that StudentPACS modules were either equivalent to or better than learning from static images or textbooks (90 +/- 3% [257 of 285], P < .00002), were not difficult to use (85 +/- 4% [248 of 293], P < .00002), presented them with clinical content that tied in well with the depicted imaging (90 +/- 3% [263 of 293], P < .00002), and taught them new information (69 +/- 5% [202 of 293], P < .00002). Most respondents felt the StudentPACS modules presented information they would find useful in clinical practice (91 +/- 3% [266 of 293], P < .00002), reported satisfactory experiences using StudentPACS modules as a source of self-directed learning material (79 +/- 5% [232 of 293], P < .00002), and stated that they would use StudentPACS modules for learning different topics in the future (85.6 +/- 4% [244 of 285], P < .00002). Medical students found using StudentPACS modules at least equivalent to, if not better than, using static books or annotated images. Copyright (c

  4. Design of multiparty consultation capability for a PACS

    NASA Astrophysics Data System (ADS)

    Reijns, Gerard L.; van der Kolk, Jean-Marc

    1996-05-01

    The PACS developed previously at the Delft University did not allow for real time interaction between specialists at different viewing stations. Recently, we enhanced our PACS with a Consultation Capability to provide a user with the ability to consult colleagues at other viewing stations. This consultation capability enables viewing the same image(s) simultaneously at different workstations and provides overlay information of pointers and rectangles, generated at one site, to become visible at the other site(s). In our earlier PACS, viewing of images is initiated by starting the Xclient application at one of the viewing stations. This procedure has been enhanced to enable a user to select two modes of operation namely either single- or multi-user session mode. In the new multi-user mode, all viewing stations involved in the same session, communicate with each other via a central control application (called consultation server), which is part of the enhanced supervisor. In the multi-user mode, only one user is allowed to select images, which will be displayed at all viewing stations involved in the session. The new viewing program sends it mouse information and framing information to the consultation server, which distributes this information to the other connected viewers. It is desired to remain DICOM compatible, however, ACR/NEMA has not (yet) handled the standardization of commands concerned with real-time consultation. Two different DICOM SOP (Service Object Pair) classes have been created. The first class is used to setup consultation, whereas the second class is used to exchange consultation data.

  5. PAC learning algorithms for functions approximated by feedforward networks

    SciTech Connect

    Rao, N.S.V.; Protopopescu, V.

    1996-06-01

    The authors present a class of efficient algorithms for PAC learning continuous functions and regressions that are approximated by feedforward networks. The algorithms are applicable to networks with unknown weights located only in the output layer and are obtained by utilizing the potential function methods of Aizerman et al. Conditions relating the sample sizes to the error bounds are derived using martingale-type inequalities. For concreteness, the discussion is presented in terms of neural networks, but the results are applicable to general feedforward networks, in particular to wavelet networks. The algorithms can be directly adapted to concept learning problems.

  6. Pacific Tracker 2 - expert system (PacTrac2-ES) behavioural assessment and intervention tool for the Pacific Kids DASH for Health (PacDASH) study.

    PubMed

    Novotny, Rachel; Nigg, Claudio; McGlone, Katalina; Renda, Gloria; Jung, Noah; Matsunaga, Masako; Karanja, Njeri

    2013-10-01

    The Pacific Tracker (PacTrac) is a computer program designed to analyse food intakes of individuals from the Pacific Region. PacTrac's original output included servings of daily intake of food groups according to the United States Food Guide Pyramid, nutrient intake recommendations, and a comparison to other national nutrition recommendations. PacTrac was made available for public use through the Hawaii Foods website (hawaiifoods.hawaii.edu). PacTrac2 is an updated and expanded version of PacTrac that uses the United States MyPyramid/MyPlate food groups in household units of daily intake, rather than servings. In addition, the PacTrac2 includes a physical activity analysis tool which quantifies minutes of physical activities and their intensities based on energy estimates from the compendium of physical activity and research on children. An Expert System (ES) - a computerised decision tree to guide behaviour change - was developed using information on self-efficacy and stage of readiness to change, and the fruit and vegetable intake and physical activity information from PacTrac2. The ES produces reports for the child, the parent/guardian, and the child's physician with child-specific strategies, targeted behavioural information, and feedback tailored to the child. PacTrac2-ES was designed for the Pacific Kids DASH for Health (PacDASH) intervention study, conducted in the Kaiser Permanente health care system in Hawaii. The intervention is based on the child's self-efficacy and stage of readiness to change intake of fruits and vegetables and physical activity, with a goal of maintaining body weight to prevent obesity. The intervention is complemented with stage-based mailers addressing the environment for physical activity and fruit and vegetable intake and newsletters that address related behaviours (sedentary activity and a DASH eating approach). This project is the first to expand the PacTrac to contain children's foods and physical activities from the Pacific

  7. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2009-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive features, and fracture zones (and wedge-shaped sites

  8. Covariant Bardeen perturbation formalism

    NASA Astrophysics Data System (ADS)

    Vitenti, S. D. P.; Falciano, F. T.; Pinto-Neto, N.

    2014-05-01

    In a previous work we obtained a set of necessary conditions for the linear approximation in cosmology. Here we discuss the relations of this approach with the so-called covariant perturbations. It is often argued in the literature that one of the main advantages of the covariant approach to describe cosmological perturbations is that the Bardeen formalism is coordinate dependent. In this paper we will reformulate the Bardeen approach in a completely covariant manner. For that, we introduce the notion of pure and mixed tensors, which yields an adequate language to treat both perturbative approaches in a common framework. We then stress that in the referred covariant approach, one necessarily introduces an additional hypersurface choice to the problem. Using our mixed and pure tensors approach, we are able to construct a one-to-one map relating the usual gauge dependence of the Bardeen formalism with the hypersurface dependence inherent to the covariant approach. Finally, through the use of this map, we define full nonlinear tensors that at first order correspond to the three known gauge invariant variables Φ, Ψ and Ξ, which are simultaneously foliation and gauge invariant. We then stress that the use of the proposed mixed tensors allows one to construct simultaneously gauge and hypersurface invariant variables at any order.

  9. Amplitudes of Spiral Perturbations

    NASA Astrophysics Data System (ADS)

    Grosbol, P.; Patsis, P. A.

    2014-03-01

    It has proven very difficult to estimate the amplitudes of spiral perturbations in disk galaxies from observations due to the variation of mass-to-light ratio and extinction across spiral arms. Deep, near-infrared images of grand-design spiral galaxies obtained with HAWK-I/VLT were used to analyze the azimuthal amplitude and shape of arms, which, even in the K-band may, be significantly biased by the presence of young stellar populations. Several techniques were applied to evaluate the relative importance of young stars across the arms, such as surface brightness of the disk with light from clusters subtracted, number density of clusters detected, and texture of the disk. The modulation of the texture measurement, which correlates with the number density of faint clusters, yields amplitudes of the spiral perturbation in the range 0.1-0.2. This estimate gives a better estimate of the mass perturbation in the spiral arms, since it is dominated by old clusters.

  10. Molecular above-threshold-ionization angular distributions with attosecond bichromatic intense XUV laser pulses

    NASA Astrophysics Data System (ADS)

    Yuan, Kai-Jun; Bandrauk, André D.

    2012-01-01

    Angular distributions of molecular above-threshold ionization (MATI) in bichromatic attosecond extreme ultraviolet (XUV) linear polarization laser pulses have been theoretically investigated. Multiphoton ionization in a prealigned molecular ion H2+ produces clear MATI spectra which show a forward-backward asymmetry in angular and momentum distributions which is critically sensitive to the carrier envelope phase (CEP) φ, the time delay Δτ between the two laser pulses, and the photoelectron kinetic energies Ee. The features of the asymmetry in MATI angular distributions are described well by multiphoton perturbative ionization models. Phase differences of continuum electron wave functions can be extracted from the CEP φ and time delay Δτ dependent ionization asymmetry ratio created by interfering multiphoton ionization pathways. At large internuclear distances MATI angular distributions exhibit more complex features due to laser-induced electron diffraction where continuum electron wavelengths are less than the internuclear distance.

  11. Angular velocity of a spheroid log rolling in a simple shear at small Reynolds number

    NASA Astrophysics Data System (ADS)

    Meibohm, Jan; Candelier, Fabien; Rosen, Tomas; Einarsson, Jonas; Lundell, Fredrik; Mehlig, Bernhard

    2016-11-01

    We analyse the angular velocity of a small neutrally buoyant spheroid log rolling in a simple shear. When the effect of fluid inertia is negligible the angular velocity ω -> equals half the fluid vorticity. We compute by singular perturbation theory how weak fluid inertia reduces the angular velocity in an unbounded shear, and how this reduction depends upon the shape of the spheroid (on its aspect ratio). In addition we determine the angular velocity by direct numerical simulations. The results are in excellent agreement with the theory at small but not too small values of the shear Reynolds number, for all aspect ratios considered. For the special case of a sphere we find ω / s = - 1 / 2 + 0 . 0540Re 3 / 2 where s is the shear rate and Re is the shear Reynolds number. This result differs from that derived by Lin et al. who obtained a numerical coefficient roughly three times larger.

  12. On Dunkl angular momenta algebra

    NASA Astrophysics Data System (ADS)

    Feigin, Misha; Hakobyan, Tigran

    2015-11-01

    We consider the quantum angular momentum generators, deformed by means of the Dunkl operators. Together with the reflection operators they generate a subalgebra in the rational Cherednik algebra associated with a finite real reflection group. We find all the defining relations of the algebra, which appear to be quadratic, and we show that the algebra is of Poincaré-Birkhoff-Witt (PBW) type. We show that this algebra contains the angular part of the Calogero-Moser Hamiltonian and that together with constants it generates the centre of the algebra. We also consider the gl( N ) version of the subalge-bra of the rational Cherednik algebra and show that it is a non-homogeneous quadratic algebra of PBW type as well. In this case the central generator can be identified with the usual Calogero-Moser Hamiltonian associated with the Coxeter group in the harmonic confinement.

  13. Nuclei at High Angular Momentum

    SciTech Connect

    Diamond, R. M.; Stephens, F. S.

    1980-12-01

    It appears that most nuclei show a compromise between purely collective and purely non-collective behavior at very high spins.non~collective behavior in nuclei has been seen only as high as 36 or 37{bar h}, at which point a more collective structure seems to develop. The concepts underlying the study of high angular momentum states are discussed. The factors that limit angular momentum in nuclei are considered. The currently emerging state of physics of very high spin states is reviewed. The detailed calculations currently made for high spin states are described, focusing not on the calculations themselves, but on the physical input to them and results that come out. Production of high-spin states using heavy-ion reactions is reviewed. Studies of {gamma}-rays de-exciting the evaporation residues from heavy-ion reactions are covered. Two types of {gamma} rays occur: those that cool the nucleus to or toward the yrast line, called "statistical," and those that are more or less parallel to the yrast line and remove the angular momentum, called "yrast~like." Collective rotation, in simplest form the motion of a deformed nucleus around an axis perpendicular to its symmetry axis, is also covered.

  14. Achromatic orbital angular momentum generator

    NASA Astrophysics Data System (ADS)

    Bouchard, Frédéric; Mand, Harjaspreet; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W.

    2014-12-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of two glued hollow axicons, is used to introduce a nonuniform rotation of polarization into a linearly polarized input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarization, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of 95% for these three different wavelengths is observed. This device may find applications in imaging from micro- to astronomical systems where a white vortex beam is needed.

  15. ACS/WFC Revised Geometric Distortion for DrizzlePac

    NASA Astrophysics Data System (ADS)

    Kozhurina-Platais, V.; Borncamp, D.; Anderson, J.; Grogin, N.; Hack, M.

    2015-06-01

    The goal of the ACS/WFC astrometric calibration for DrizzlePac is to provide a coordinate system free of distortion to a precision level of ˜0.1 pixels (˜ 5mas). The astrometric calibration of ACS/WFC is based on the astrometric standard field in the vicinity of globular cluster 47 Tuc. We used a polynomial model to derive the geometric distortion in the WFC channel relative to the distortion-free coordinates, which now accounts for proper motions of stars in the astrometric field. A new and straightforward representation of time-dependent distortion in the linear terms is now implemented in the IDCTAB reference file and in the STScI software DrizzlePac to obtain simultaneously the ACS/WFC geometric distortion and its time-dependent correction. As a result, the geometric distortion can be corrected down to a precision level of 0.02 pix (1mas), which allows now for improvement of the alignment and registration of the ACS/WFC images with accuracy of ˜0.05 pix (2.5mas) or better.

  16. Herschel PACS and SPIRE imaging of CW Leonis

    NASA Astrophysics Data System (ADS)

    Ladjal, D.; Barlow, M. J.; Groenewegen, M. A. T.; Ueta, T.; Blommaert, J. A. D. L.; Cohen, M.; Decin, L.; De Meester, W.; Exter, K.; Gear, W. K.; Gomez, H. L.; Hargrave, P. C.; Huygen, R.; Ivison, R. J.; Jean, C.; Kerschbaum, F.; Leeks, S. J.; Lim, T. L.; Olofsson, G.; Polehampton, E.; Posch, T.; Regibo, S.; Royer, P.; Sibthorpe, B.; Swinyard, B. M.; Vandenbussche, B.; Waelkens, C.; Wesson, R.

    2010-07-01

    Herschel PACS and SPIRE images have been obtained over a 30' × 30' area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of 22' diameter, which is cospatial with the termination shock due to interaction with the interstellar medium (ISM) as defined by Sahai & Chronopoulos from ultraviolet GALEX images. Fluxes are derived in the 70, 160, 250, 350, and 550 μm bands in the region where the interaction with the ISM takes place, and this can be fitted with a modified black body with a temperature of 25 ± 3 K. Using the published proper motion and radial velocity for the star, we derive a heliocentric space motion of 25.1 km s-1. Using the PACS and SPIRE data and the analytical formula of the bow shock structure, we infer a de-projected standoff distance of the bow shock of R0 = (8.0 ± 0.3) × 1017 cm. We also derive a relative velocity of the star with respect to the ISM of (106.6 ± 8.7)/√{n_ISM} km s-1, where nISM is the number density of the local ISM. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  17. Automatic programming of binary morphological machines by PAC learning

    NASA Astrophysics Data System (ADS)

    Barrera, Junior; Tomita, Nina S.; Correa da Silva, Flavio S.; Terada, Routo

    1995-08-01

    Binary image analysis problems can be solved by set operators implemented as programs for a binary morphological machine (BMM). This is a very general and powerful approach to solve this type of problem. However, the design of these programs is not a task manageable by nonexperts on mathematical morphology. In order to overcome this difficulty we have worked on tools that help users describe their goals at higher levels of abstraction and to translate them into BMM programs. Some of these tools are based on the representation of the goals of the user as a collection of input-output pairs of images and the estimation of the target operator from these data. PAC learning is a well suited methodology for this task, since in this theory 'concepts' are represented as Boolean functions that are equivalent to set operators. In order to apply this technique in practice we must have efficient learning algorithms. In this paper we introduce two PAC learning algorithms, both are based on the minimal representation of Boolean functions, which has a straightforward translation to the canonical decomposition of set operators. The first algorithm is based on the classical Quine-McCluskey algorithm for the simplification of Boolean functions, and the second one is based on a new idea for the construction of Boolean functions: the incremental splitting of intervals. We also present a comparative complexity analysis of the two algorithms. Finally, we give some application examples.

  18. Effectiveness of wireless communication using 100-Mbps infrared in PACS

    NASA Astrophysics Data System (ADS)

    Ha, Doo-Hoe; Moon, Man-Sik; Jang, Dong-Yeol; Hwang, Yeon-Soo; Ok, Min-Ah; Choi, Seung-Yong

    2002-05-01

    In our hospital, two buildings are separated by public road and was communicated each other using 2 Mbps public cable network. Recently inter-building communication with 100 Mbps infrared has been established for PACS. Gigabit network has been established in the main building. To evaluate usefulness of infrared communication, actual data transfer rate was checked. When 2 Mbps public cable was used, actual data transfer rate using 32 Mbytes text file was 193.9 Mbps. After infrared communication was established, effective network speed between two link heads of infrared was 45 Mbps. Actual data transfer rate with 32 Mbytes text file was 4.98 Mbps. Average transfer rates was also checked each 10 times using compressed medical images of each modalities from CR (4 Mbytes), ultrasound (200 Kbytes), CT (250 Kbytes), MRI (77.6 Kbytes) and fluoroscopy (1 Mbytes), and using a raw data of CR (28 Mbytes). Total average transfer rate was 4.91 Mbps. To compare data transfer rate in the separated building with them in the main building, the rate with a 14 Mbytes CR was checked 10 times at the each building. Average data transfer rate was 6.93 Mbps in the main building and 4.05 Mbps in the separated building. In conclusion, when two hospital buildings are separated, an infrared networking can be replaced for fiber-optic cable networking in PACS environment.

  19. Impact of PACS On The Organization Of Radiology Departments

    NASA Astrophysics Data System (ADS)

    Zielonka, Jason S.

    1983-05-01

    The radiologist serves as a consultant to other physicians in the practice of clinical medicine; the image obtained and the reported interpretation of that image represent the service rendered and are therefore of major importance (medically, legally and economically) to the radiologist. Because many radiology departments are organized along subspecialty lines or (in the case of a single department serving several institutions) along combined institutional and subspecialty lines, many patients may undergo diagnostic evaluation sequences in which several studies are performed and multiple simultaneous consultations may result. In the past, the lack of availability of multiple copies of the study (for multiple interested parties) has prevented the effective tailoring of subsequent examinations until the prior exam results were available; the advent of digital networks for PACS may result in a significant change in this procedure and, accordingly, in the pattern of interpretation, internal referral and organization of radiology departments. In addition, since clinicians may have access to studies directly and, possibly, prior to official interpretation, the nature of the relationship between the clinician and the radiologist may be altered by PACS.

  20. ATM-distributed PACS server for ICU application

    NASA Astrophysics Data System (ADS)

    Lee, Joseph K.; Wong, Albert W. K.; Huang, H. K.; Bazzill, Todd M.; Zhang, Jianguo; Andriole, Katherine P.

    1996-05-01

    In order for PACS (Picture Archiving and Communications System) to better serve our intensive care units (ICUs), we, at University of California, San Francisco, have designed and developed a client/server application that is specifically tailored to provide fast, reliable access to our PACS data from diagnostic viewing stations in the ICUs. One of our utmost design criteria is to ensure consistent delivery of high speed, high performance data throughput, and yet, the system should be cost-effective and render minimal maintenance. As high technology advances, we are able to utilize powerful mass storage device such as raid disk, which serves as a central image repository, to store images and data. We are also able to utilize Asynchronous Transfer Mode (ATM) technology, which is regarded as the prevailing technology for reliable, high speed data communications, to transfer large imagery data sets across systems and networks. This paper describes the design and mechanism of how ICU viewing stations take advantages of sharing a high performance raid disk, and ATM technology in data transfer for timely delivery of images in a clinical setting.

  1. RadSearch: a RIS/PACS integrated query tool

    NASA Astrophysics Data System (ADS)

    Tsao, Sinchai; Documet, Jorge; Moin, Paymann; Wang, Kevin; Liu, Brent J.

    2008-03-01

    Radiology Information Systems (RIS) contain a wealth of information that can be used for research, education, and practice management. However, the sheer amount of information available makes querying specific data difficult and time consuming. Previous work has shown that a clinical RIS database and its RIS text reports can be extracted, duplicated and indexed for searches while complying with HIPAA and IRB requirements. This project's intent is to provide a software tool, the RadSearch Toolkit, to allow intelligent indexing and parsing of RIS reports for easy yet powerful searches. In addition, the project aims to seamlessly query and retrieve associated images from the Picture Archiving and Communication System (PACS) in situations where an integrated RIS/PACS is in place - even subselecting individual series, such as in an MRI study. RadSearch's application of simple text parsing techniques to index text-based radiology reports will allow the search engine to quickly return relevant results. This powerful combination will be useful in both private practice and academic settings; administrators can easily obtain complex practice management information such as referral patterns; researchers can conduct retrospective studies with specific, multiple criteria; teaching institutions can quickly and effectively create thorough teaching files.

  2. Distributing the server function in a multiring PAC system

    NASA Astrophysics Data System (ADS)

    Lynne, Kenton J.

    1991-07-01

    Retrieving medical images from a PACS database presents formidable requirements in terms of communications bandwidth and end-user response time. In the Mayo/IBM PAC System, these requirements are even more challenging due to the size and topology of the Mayo campus and the number of images being handled. Accordingly, early on in the project it was decided to distribute the server function among the local rings that make up the installation. Entities called MIDS Servers -- high-end IBM PS/2 computers with a considerable amount of fast DASD -- were designed to attach to a local ring and provide medical images to the medical review stations attached to that ring. In keeping with the cooperative processing philosophy of the overall system, MIDS Servers are semi-autonomous units that are responsible for their own integrity and communicate with the other components of the system as needed to perform their function. Through a strategy that tries to ensure that medical images reside on the MIDS Servers most likely to require them, the authors attempt to minimize the need to retrieve images from the optical archive and reduce inter-ring image traffic. Distributing the server function this way should provide a total server bandwidth greater than the 4Mb/sec capacity of the Token-Ring, as well as faster end-user response time.

  3. Perturbation of mass accretion rate, associated acoustic geometry and stability analysis

    NASA Astrophysics Data System (ADS)

    Bollimpalli, Deepika A.; Bhattacharya, Sourav; Das, Tapas K.

    2017-02-01

    We investigate the stability of stationary integral solutions of an ideal irrotational fluid in a general static and spherically symmetric background, by studying the profile of the perturbation of the mass accretion rate. We consider low angular momentum axisymmetric accretion flows for three different accretion disk models and consider time dependent and radial linear perturbation of the mass accretion rate. First we show that the propagation of such perturbation can be determined by an effective 2 × 2 matrix, which has qualitatively similar acoustic causal properties as one obtains via the perturbation of the velocity potential. Next, using this matrix we analytically address the stability issues, for both standing and travelling wave configurations generated by the perturbation. Finally, based on this general formalism we briefly discuss the explicit example of the Schwarzschild spacetime and compare our results of stability with the existing literature, which instead address this problem via the perturbation of the velocity potential.

  4. Attitude dynamics of gyrostat-satellites under control by magnetic actuators at small perturbations

    NASA Astrophysics Data System (ADS)

    Doroshin, Anton V.

    2017-08-01

    The angular motion of gyrostat-satellites with one axial rotor is considered under control by magnetic actuators and at the action of small polyharmonic perturbations of the own dipole magnetic moment's components which are created proportionally to components of the angular velocity of the satellite. The attitude dynamics is investigated in conditions of the coincidence of the vector of magnetic induction of the external magnetic field and the initial angular momentum vector of the satellite. General and heteroclinic analytical solutions are obtained for dynamical parameters at the relative smallness of the magnetic torques. The chaotic regimes are examined on the base of the Melnikov method and Poincaré sections.

  5. A novel robot for imposing perturbations during overground walking: mechanism, control and normative stepping responses.

    PubMed

    Olenšek, Andrej; Zadravec, Matjaž; Matjačić, Zlatko

    2016-06-11

    The most common approach to studying dynamic balance during walking is by applying perturbations. Previous studies that investigated dynamic balance responses predominantly focused on applying perturbations in frontal plane while walking on treadmill. The goal of our work was to develop balance assessment robot (BAR) that can be used during overground walking and to assess normative balance responses to perturbations in transversal plane in a group of neurologically healthy individuals. BAR provides three passive degrees of freedom (DoF) and three actuated DoF in pelvis that are admittance-controlled in such a way that the natural movement of pelvis is not significantly affected. In this study BAR was used to assess normative balance responses in neurologically healthy individuals by applying linear perturbations in frontal and sagittal planes and angular perturbations in transversal plane of pelvis. One way repeated measure ANOVA was used to statistically evaluate the effect of selected perturbations on stepping responses. Standard deviations of assessed responses were similar in unperturbed and perturbed walking. Perturbations in frontal direction evoked substantial pelvis displacement and caused statistically significant effect on step length, step width and step time. Likewise, perturbations in sagittal plane also caused statistically significant effect on step length, step width and step time but with less explicit impact on pelvis movement in frontal plane. On the other hand, except from substantial pelvis rotation angular perturbations did not have substantial effect on pelvis movement in frontal and sagittal planes while statistically significant effect was noted only in step length and step width after perturbation in clockwise direction. Results indicate that the proposed device can repeatedly reproduce similar experimental conditions. Results also suggest that "stepping strategy" is the dominant strategy for coping with perturbations in frontal plane

  6. Angular momentum decomposition for an electron

    SciTech Connect

    Burkardt, Matthias; Hikmat, BC

    2009-04-01

    We calculate the orbital angular momentum of the 'quark' in the scalar diquark model as well as that of the electron in QED (to order {alpha}). We compare the orbital angular momentum obtained from the Jaffe-Manohar decomposition to that obtained from the Ji relation and estimate the importance of the vector potential in the definition of orbital angular momentum.

  7. Angular Momentum Decomposition for an Electron

    SciTech Connect

    Burkardt, Matthias; BC, Hikmat

    2009-01-01

    We calculate the orbital angular momentum of the `quark' in the scalar diquark model as well as that of the electron in QED (to order $\\alpha$). We compare the orbital angular momentum obtained from the Jaffe-Manohar decomposition to that obtained from the Ji relation and estimate the importance of the vector potential in the definition of orbital angular momentum.

  8. Planning, expectation, and image evaluation for PACS at the University of Iowa Hospitals and Clinics

    NASA Astrophysics Data System (ADS)

    Franken, E. A., Jr.; Smith, Wilbur L.; Berbaum, Kevin S.; Owen, David A.; Hilsenrath, Peter

    1990-08-01

    Our strategy in studying PACS is to evaluate its clinical implementation working with equipment supplied by an established manufacturer. Fiscal and personnel resources required to design and integrate the hardware components and operational software to develop a functional PACS precluded a bottom up development approach at our institution. Imaging equipment vendors possess more abundant design development resources for this task and therefore can support a more rapid development of the initial components of PACS. For this reason we have chosen to serve as a beta test site to study the viability of the basic PACS components in a clinical setting. Our efforts primarily focus on: (1) image quality; (2) cost effectiveness; (3) PACS/HIS/RIS integration; (4) equipment and software reliability; and (5) overall system performance. The results of our studies are shared with the vendor for future PACS development and refi nement. To attain our investigational goals we have formed an interdisciplinary team of Radiologists, Perceptual Psychologist, Economist, Electrical and Industrial Engineers, Hospital Information System personnel and key departmental administrative staff. For several reasons Pediatric Radiology was targeted as the initial area for our PACS study: a small area representative of the overall operation,tight operational controls and willingness of physicians. We used a step-wise approach, the first step being the installation of PACS exclusively within the physical confines of Pediatric Radiology.

  9. How to Develop PACs. Performance and Competency-based Student Materials.

    ERIC Educational Resources Information Center

    Rouse, Bill, Comp.

    This booklet is designed for developing performance and competency-based student materials (PACs). The PAC, an instructional tool that focuses on helping students master a specific objective, lends itself to vocational instruction. The first nine sections of the guide, consisting of information to assist teachers in gathering background materials…

  10. Construct Reliability of the Probability of Adoption of Change (PAC) Model.

    ERIC Educational Resources Information Center

    Creamer, E. G.; And Others

    1991-01-01

    Describes Probability of Adoption of Change (PAC) model, theoretical paradigm for explaining likelihood of successful adoption of planned change initiatives in student affairs. Reports on PAC construct reliability from survey of 62 Chief Student Affairs Officers. Discusses two refinements to the model: merger of leadership and top level support…

  11. Properties And Coefficient Program For The Calculation Of Thermodynamic Data (PAC2)

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.

    1989-01-01

    Program calculates ideal gas thermodynamic properties for any species for which molecular constant data available, and offers user choice of methodologies for performing thermodynamic calculations. PAC2 updated to PAC4. Improvements include increased user friendliness and ability to extrapolate thermodynamic properties for gases to higher temperatures using Wilhoit's formulas.

  12. PACS used while on-call: a national survey of radiology program directors and chief residents.

    PubMed

    Tesoriero, Joseph A; Eddy, Paul; Hasso, Anton N

    2015-04-01

    The aim of this study was to determine the prevalence of different diagnostic image viewing platforms used by radiologists while on-call, and to assess the opinions and preferences of radiology program directors and chief residents regarding their use. An online survey was sent electronically to radiology residency program directors and chief residents via the Association of University Radiologists. Forty-two radiology program directors and 25 chief residents completed the survey, yielding response rates of 24.9 and 8.5 %, respectively. From the survey results, 10 different Picture Archiving Communications Systems (PACS) were identified; GE (25 %), Philips (17 %), and Agfa Impax (15 %) were the most prevalent. Interestingly, only 5 % of all respondents use a secondary "Digital Imaging and Communications in Medicine" viewer for on-call studies. Perceptions of PACS functionality were generally neutral to weakly positive. Most respondents strongly agreed that it is important to have a single integrated PACS for viewing on-call studies and agreed that the PACS should be integrated into the Electronic Medical Records (EMR). The overwhelming majority of respondents use their institution's PACS while on-call. The results show there is still a wide variety of PACS platforms used by different institutions; however, GE, Phillips, and Agfa were some of the most prevalent. Most radiologists surveyed have neutral to slightly positive perceptions about the functionality and ease of use of their PACS. Finally, while radiologists agree that PACS should be integrated with EMR, only 53 % of respondents currently have this arrangement.

  13. Discrete reductive perturbation technique

    SciTech Connect

    Levi, Decio; Petrera, Matteo

    2006-04-15

    We expand a partial difference equation (P{delta}E) on multiple lattices and obtain the P{delta}E which governs its far field behavior. The perturbative-reductive approach is here performed on well-known nonlinear P{delta}Es, both integrable and nonintegrable. We study the cases of the lattice modified Korteweg-de Vries (mKdV) equation, the Hietarinta equation, the lattice Volterra-Kac-Van Moerbeke equation and a nonintegrable lattice KdV equation. Such reductions allow us to obtain many new P{delta}Es of the nonlinear Schroedinger type.

  14. Perturbative cavity quantum electrodynamics

    SciTech Connect

    Hinds., E.A.

    1994-12-31

    Charged particles are coupled to the electromagnetic radiation field at a fundamental level. Even in a vacuum, an atom is perturbed by the zero-point quantum noise of the electromagnetic field, and this coupling is responsible for some basic phenomena such as the Lamb shift and spontaneous radiative decay. These radiative effects can be calculated to high precision using the theory of quantum electrodynamics (QED), and for cases when the atom is in free space, remarkable agreement has been found between theory and experiment. One is led to conclude QED provides a reliable description of the coupling between the charged particles and electromagnetic fields. 101 refs., 20 figs.

  15. Full-sky formulae for weak lensing power spectra from total angular momentum method

    NASA Astrophysics Data System (ADS)

    Yamauchi, Daisuke; Namikawa, Toshiya; Taruya, Atsushi

    2013-08-01

    We systematically derive full-sky formulae for the weak lensing power spectra generated by scalar, vector and tensor perturbations from the total angular momentum (TAM) method. Based on both the geodesic and geodesic deviation equations, we first give the gauge-invariant expressions for the deflection angle and Jacobi map as observables of the CMB lensing and cosmic shear experiments. We then apply the TAM method, originally developed in the theoretical studies of CMB, to a systematic derivation of the angular power spectra. The TAM representation, which characterizes the total angular dependence of the spatial modes projected along a line-of-sight, can carry all the information of the lensing modes generated by scalar, vector, and tensor metric perturbations. This greatly simplifies the calculation, and we present a complete set of the full-sky formulae for angular power spectra in both the E-/B-mode cosmic shear and gradient-/curl-mode lensing potential of deflection angle. Based on the formulae, we give illustrative examples of non-vanishing B-mode cosmic shear and curl-mode of deflection angle in the presence of the vector and tensor perturbations, and explicitly compute the power spectra.

  16. Full-sky formulae for weak lensing power spectra from total angular momentum method

    SciTech Connect

    Yamauchi, Daisuke; Taruya, Atsushi; Namikawa, Toshiya E-mail: namikawa@yukawa.kyoto-u.ac.jp

    2013-08-01

    We systematically derive full-sky formulae for the weak lensing power spectra generated by scalar, vector and tensor perturbations from the total angular momentum (TAM) method. Based on both the geodesic and geodesic deviation equations, we first give the gauge-invariant expressions for the deflection angle and Jacobi map as observables of the CMB lensing and cosmic shear experiments. We then apply the TAM method, originally developed in the theoretical studies of CMB, to a systematic derivation of the angular power spectra. The TAM representation, which characterizes the total angular dependence of the spatial modes projected along a line-of-sight, can carry all the information of the lensing modes generated by scalar, vector, and tensor metric perturbations. This greatly simplifies the calculation, and we present a complete set of the full-sky formulae for angular power spectra in both the E-/B-mode cosmic shear and gradient-/curl-mode lensing potential of deflection angle. Based on the formulae, we give illustrative examples of non-vanishing B-mode cosmic shear and curl-mode of deflection angle in the presence of the vector and tensor perturbations, and explicitly compute the power spectra.

  17. Angular momentum blockade in nanoscale high-Tc superconducting grains

    NASA Astrophysics Data System (ADS)

    Mancarella, Francesco; Balatsky, Alexander; Wallin, Mats; Rosengren, Anders; Nordita-Condensed Matter Collaboration; KTH-Theoretical Physics Collaboration

    2014-03-01

    We discuss the angular momentum blockade in small d-wave SC grains in an external magnetic field. We find abrupt changes in angular momentum state of the condensate (''angular momentum blockade'') as a result of the variation of the external field. The effect represents a direct analog of the Coulomb blockade. We use the Ginzburg-Landau theory to illustrate how the field turns a d-wave order parameter (OP) into a(dx2 -y2 + idxy)-OP. We derive the volume magnetic susceptibility as a function of the field, and corresponding small jumps in magnetization at critical values of the field that should be experimentally observable in SC grains. The observation of these jumps requires a small grain, since their extent is inversely proportional to the number of Cooper pairs in the sample. The general source of instability of the pure d-wave gap is the presence of gap nodes, completely lifted by the secondary OP component. A d + id' -state is chiral and hence has an orbital moment carried by Cooper pairs. We consider fields H <perturbations of the OP. Boundary effects will be also discussed. Recent experiments suggest that nanoscale d-wave SC can be fully gapped and this minimal gap can be modified by an external field. Work supported by the Swedish Research Council grants VR 621-2012-298, VR 621-2012-3984, ERC and DOE.

  18. Effect of the antimicrobial peptide D-Nal-Pac-525 on the growth of Streptococcus mutans and its biofilm formation.

    PubMed

    Li, Huajun; Cheng, Jya-Wei; Yu, Hui-Yuan; Xin, Yi; Tang, Li; Ma, Yufang

    2013-08-01

    Streptococcus mutans is the primary etiological agent of dental caries. The antimicrobial peptide D-Nal-Pac-525 was designed by replacing the tryptophans of the Trp-rich peptide Pac-525 with D-β-naphthyalanines. To assess the effect of D-Nal-Pac-525 on cariogenic bacteria, the activity of D-Nal-Pac-525 on the growth of S. mutans and its biofilm formation were examined. D-Nal- Pac-525 showed robust antimicrobial activity against S. mutans (minimum inhibitory concentration of 4 μg/ml). Using scanning electron microscopy and transmission electron microscopy, it was shown that D-Nal-Pac-525 caused morphological changes and damaged the cell membrane of S. mutans. D-Nal-Pac-525 inhibited biofilm formation of S. mutans at 2 μg/ml. The results of this study suggest that D-Nal-Pac-525 has great potential for clinical application as a dental caries-preventing agent.

  19. Thermal-hydraulic/heat transfer code development for sphere-pac-fueled LMFBRs. [COBRA-3SP code

    SciTech Connect

    Morris, D.G.

    1980-06-01

    Sphere-pac fuel has received much attention recently in light of the development of proliferation-resistant fuel cycles for the Fast Breeder Reactor Program in the United States. However, for sphere-pac fuel to be a viable alternative to conventional pellet fuel, a means to analyze the thermal behavior of sphere-pac-fueled pin bundles is needed. To meet this need, a thermal-hydraulic/heat transfer computer code has been developed for sphere-pac-fueled fast breeder reactors. The code, COBRA-3SP, is a modified version of COBRA-3M incorporating a three-region sphere-pac fuel pin model which permits fuel restructuring. With COBRA-3SP, steady-state and transient analysis of sphere-pac-fueled pin bundles is possible. The validity of the sphere-pac fuel pin model has been verified using experimental results of irradiated sphere-pac fuel.

  20. Two-dimensional angular filter array for angular domain imaging with 3D printed angular filters

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Carson, Jeffrey J. L.

    2013-02-01

    Angular Domain Imaging (ADI) is a technique that is capable of generating two dimensional shadowgrams of attenuating targets embedded in a scattering medium. In ADI, an angular filter array (AFA) is positioned between the sample and the detector to distinguish between quasi-ballistic photons and scattered photons. An AFA is a series of micro-channels with a high aspect ratio. Previous AFAs from our group were constructed by micro-machining the micro-channels into a silicon wafer, limiting the imaging area to a one dimensional line. Two dimensional images were acquired via scanning. The objective of this work was to extend the AFA design to two dimensions to allow for two dimensional imaging with minimal scanning. The second objective of this work was to perform an initial characterization of the imaging capabilities of the 2D AFA. Our approach was to use rapid 3D prototyping techniques to generate an array of micro-channels. The imaging capabilities were then evaluated by imaging a 0.9 mm graphite rod submerged in a scattering media. Contrast was observed to improve when a second angular filter array was placed in front of the sample to mask the incoming light.

  1. [Study on the distributed integration of the HIS and PACS based on CORBA].

    PubMed

    Zhang, Quanhai; Shi, Pengfei

    2004-02-01

    In medical clinical practice, physicians need to acquire the image and text information of the patient. All the information will be of benefit for physicians to diagnose disease, improve clinical treatment, and do research work. But the information is distributed in different systems, such as medical image information in PACS (Picture Archiving and Communication System) and text records in HIS (Hospital Information System). Today many hospitals are suffering from lack of an integrated system with PACS and HIS. This paper compares PACS with HIS and puts forward a distributed integration method of integrating the PACS and HIS with the prevailing WWW technology. In such a method, the image and the text information are regarded as the common object and the operation whereon as the object operation. Thus the method integrates the PACS with HIS effectively and implements the information resources sharing with the use of web technology.

  2. PACS--and beyond. A journey to the digital promised land.

    PubMed

    Viau, Mark A

    2004-01-01

    A successful picture archiving and communication system (PACS) integration depends on much more than the technology; marketing also plays a large role. This fact was evident from the inception of the PACS project at Boca Raton Community Hospital (BRCH). Strategic and effective marketing efforts should target technologists, nurses, physicians (including radiologists), administration, and colleagues in other departments. The buy-in of these users is critical to the project's success. BRCH's first marketing effort took place during the initial PACS presentation made to the hospital's board of directors. Once approval was given and a 6-month implementation target was set, a strategic and effective marketing/education plan commenced. Posters, brochures, t-shirts, and promotional items were distributed in a coordinated effort to target hospital staff and referring physician offices. Through its "Got PACS?" branding and other identity materials, BRCH implemented a marketing plan that informed, educated, and engaged PACS users.

  3. Fault tolerance techniques to assure data integrity in high-volume PACS image archives

    NASA Astrophysics Data System (ADS)

    He, Yutao; Huang, Lu J.; Valentino, Daniel J.; Wingate, W. Keith; Avizienis, Algirdas

    1995-05-01

    Picture archiving and communication systems (PACS) perform the systematic acquisition, archiving, and presentation of large quantities of radiological image and text data. In the UCLA Radiology PACS, for example, the volume of image data archived currently exceeds 2500 gigabytes. Furthermore, the distributed heterogeneous PACS is expected to have near real-time response, be continuously available, and assure the integrity and privacy of patient data. The off-the-shelf subsystems that compose the current PACS cannot meet these expectations; therefore fault tolerance techniques had to be incorporated into the system. This paper is to report our first-step efforts towards the goal and is organized as follows: First we discuss data integrity and identify fault classes under the PACS operational environment, then we describe auditing and accounting schemes developed for error-detection and analyze operational data collected. Finally, we outline plans for future research.

  4. Grid-based medical image workflow and archiving for research and enterprise PACS applications

    NASA Astrophysics Data System (ADS)

    Erberich, Stephan G.; Dixit, Manasee; Chen, Vincent; Chervenak, Ann; Nelson, Marvin D.; Kesselmann, Carl

    2006-03-01

    PACS provides a consistent model to communicate and to store images with recent additions to fault tolerance and disaster reliability. However PACS still lacks fine granulated user based authentication and authorization, flexible data distribution, and semantic associations between images and their embedded information. These are critical components for future Enterprise operations in dynamic medical research and health care environments. Here we introduce a flexible Grid based model of a PACS in order to add these methods and to describe its implementation in the Children's Oncology Group (COG) Grid. The combination of existing standards for medical images, DICOM, and the abstraction to files and meta catalog information in the Grid domain provides new flexibility beyond traditional PACS design. We conclude that Grid technology demonstrates a reliable and efficient distributed informatics infrastructure which is well applicable to medical informatics as described in this work. Grid technology will provide new opportunities for PACS deployment and subsequently new medical image applications.

  5. Derivatives of Procaspase-Activating Compound 1 (PAC-1) and their Anticancer Activities.

    PubMed

    Roth, Howard S; Hergenrother, Paul J

    2016-01-01

    PAC-1 induces the activation of procaspase-3 in vitro and in cell culture by chelation of inhibitory labile zinc ions via its ortho-hydroxy-N-acylhydrazone moiety. First reported in 2006, PAC-1 has shown promise in cell culture and animal models of cancer, and a Phase I clinical trial in cancer patients began in March 2015 (NCT02355535). Because of the considerable interest in this compound and a well-defined structure-activity relationship, over 1000 PAC-1 derivatives have been synthesized in an effort to vary pharmacological properties such as potency and pharmacokinetics. This article provides a comprehensive examination of all PAC-1 derivatives reported to date. A survey of PAC-1 derivative libraries is provided, with an indepth discussion of four derivatives on which extensive studies have been performed.

  6. Medical Image Resource Center--making electronic teaching files from PACS.

    PubMed

    Lim, C C Tchoyoson; Yang, Guo Liang; Nowinski, Wieslaw L; Hui, Francis

    2003-12-01

    A picture archive and communications system (PACS) is a rich source of images and data suitable for creating electronic teaching files (ETF). However, the potential for PACS to support nonclinical applications has not been fully realized: at present there is no mechanism for PACS to identify and store teaching files; neither is there a standardized method for sharing such teaching images. The Medical Image Resource Center (MIRC) is a new central image repository that defines standards for data exchange among different centers. We developed an ETF server that retrieves digital imaging and communication in medicine (DICOM) images from PACS, and enables users to create teaching files that conform to the new MIRC schema. We test-populated our ETF server with illustrative images from the clinical case load of the National Neuroscience Institute, Singapore. Together, PACS and MIRC have the potential to benefit radiology teaching and research.

  7. Clinical experience of Hokkaido University-PACS and FCR-angiography.

    PubMed

    Terae, S; Hawkin, S; Sato, Y; Kikuchi, Y; Abe, S; Miyasaka, K

    1994-05-01

    Three years' experience with Hokkaido University-PACS (HU-PACS) is reported. In particular, this paper describes the suitability of FCR-angiography for HU-PACS, which has been in clinical use since March 1991. Image quality of FCR-arteriograms was evaluated in the head-and-face region and the abdominal region independently. The image quality in both regions was excellent. Quality of transferred images to image workstation for HU-PACS with 10:1 data compression was also evaluated, and no appreciable image degradation or loss of information was found in the transferred images. There was no significant difference in the examination time required for one patient in abdominal angiography between conventional angiography and FCR-angiography. In summary, FCR-angiography is suitable for HU-PACS as its image acquisition modality.

  8. Derivatives of Procaspase-Activating Compound 1 (PAC-1) and Anticancer Activities

    PubMed Central

    Roth, Howard S.; Hergenrother, Paul J.

    2016-01-01

    PAC-1 induces the activation of procaspase-3 in vitro and in cell culture by chelation of inhibitory labile zinc ions via its ortho-hydroxy-N-acylhydrazone moiety. First reported in 2006, PAC-1 has shown promise in cell culture and animal models of cancer, and a Phase I clinical trial in cancer patients began in March 2015 (NCT02355535). Because of the considerable interest in this compound and a well-defined structure-activity relationship, over 1000 PAC-1 derivatives have been synthesized in an effort to vary pharmacological properties such as potency and pharmacokinetics. This article provides a comprehensive examination of all PAC-1 derivatives reported to date. A survey of PAC-1 derivative libraries is provided, with an in-depth discussion of four derivatives on which extensive studies have been performed. PMID:26630918

  9. Transition from partial to full PACS at a 450,000 exams/year hospital

    NASA Astrophysics Data System (ADS)

    Ro, Duk-Woo; Byun, Hong Sik; Choo, In W.; Kim, Bo K.; Lim, Jae H.

    1997-05-01

    The purpose of this paper is to describe the transition of a 1,100 beds tertiary hospital from 50 percent softcopy operation to full PACS operation. For the past 2 years, radiologists and clinicians have been using PACS to provide softcopy services to the outpatient clinics and inpatient wards of orthopedics surgery, neurosurgery and neurology as well as emergency room, surgical intensive care unit, medical intensive unit, pediatrics intensive care unit and neonatal intensive care unit. The examinations requested by these departments account for about 50 percent of hospital's radiological exams. In September 1996, we began the second phase of PACS implementation and installed additional workstations in the remaining wards and clinics, interfaced to PACS additional imaging modalities, and increased the capacity of both the image server and optical juke boxes. As of January 1997, we are in the final phase of moving away from conventional film system to full PACS operation.

  10. Optical angular momentum in classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Mansuripur, Masud

    2017-06-01

    Invoking Maxwell’s classical equations in conjunction with expressions for the electromagnetic (EM) energy, momentum, force, and torque, we use a few simple examples to demonstrate the nature of the EM angular momentum. The energy and the angular momentum of an EM field will be shown to have an intimate relationship; a source radiating EM angular momentum will, of necessity, pick up an equal but opposite amount of mechanical angular momentum; and the spin and orbital angular momenta of the EM field, when absorbed by a small particle, will be seen to elicit different responses from the particle.

  11. Perturbations of gravitational instantons

    NASA Astrophysics Data System (ADS)

    Torre, C. G.

    1990-06-01

    Ashtekar's spinorial formulation of general relativity is used to study perturbations of gravitational instantons corresponding to finite-action solutions of the Euclidean Einstein equations (with a nonzero cosmological constant) possessing an anti-self-dual Weyl curvature tensor. It is shown that, with an appropriate ``on-shell'' form of infinitesimal gauge transformations, the space of solutions to the linearized instanton equation can be described in terms of an elliptic complex; the cohomology of the complex defines gauge-inequivalent perturbations. Using this elliptic complex we prove that there are no nontrivial solutions to the linearized instanton equation on conformally anti-self-dual Einstein spaces with a positive cosmological constant. Thus, the space of gravitational instantons is discrete when the cosmological constant is positive; i.e., the dimension of the gravitational moduli space in this case is zero. We discuss the issue of linearization stability as well as the feasibility of using the Atiyah-Singer index theorem to compute the dimension of the gravitational moduli space when the cosmological constant is negative.

  12. Integrating organic micropollutant removal into tertiary filtration: Combining PAC adsorption with advanced phosphorus removal.

    PubMed

    Altmann, Johannes; Sperlich, Alexander; Jekel, Martin

    2015-11-01

    Direct addition of powdered activated carbon (PAC) to a deep-bed filter was investigated at pilot-scale as a single advanced treatment stage for simultaneous removal of organic micropollutants (OMPs) and phosphorus from secondary effluent. PAC doses of 10-50 mg/L were assessed with regard to their impacts on filter performance and removal of 15 selected OMPs over a period of 18 months. The PAC was effectively retained by the filter and had no negative effect on filter head loss. Filter runtime until particle breakthrough depended mainly on coagulant dose and did not decrease significantly due to the additional PAC load. Removal of suspended solids and phosphorus by coagulation was effective independent of the PAC dose. A PAC dose of 35 mg/L PAC was suitable to remove well-adsorbing OMPs (e.g. carbamazepine, diclofenac) by >80% and medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) by 50-80%. Median removals were 50-80% for well-adsorbing and 30-50% for medium adsorbing OMPs with 20 mg/L PAC. Abatement of all OMPs was low (<50%) with 10 mg/L PAC, possibly because of the high effluent organic matter content (median dissolved organic carbon (DOC) concentrations of 11.2 mg/L). In addition to adsorptive removal, relevant concentration decreases of certain OMPs (e.g. 4-formylaminoantipyrine) were attributed to biological transformation in the filter. Adsorption onto accumulating PAC in the top layer of the filter bed led to improved OMP adsorption with increasing filter runtime. The comparison of OMP removal in the pilot filter with laboratory adsorption tests demonstrates that batch test results can be applied to estimate adsorptive OMP removal in real applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. pH Signaling in Sclerotinia sclerotiorum: Identification of a pacC/RIM1 Homolog

    PubMed Central

    Rollins, Jeffrey A.; Dickman, Martin B.

    2001-01-01

    Sclerotinia sclerotiorum acidifies its ambient environment by producing oxalic acid. This production of oxalic acid during plant infection has been implicated as a primary determinant of pathogenicity in this and other phytopathogenic fungi. We found that ambient pH conditions affect multiple processes in S. sclerotiorum. Exposure to increasing alkaline ambient pH increased the oxalic acid accumulation independent of carbon source, sclerotial development was favored by acidic ambient pH conditions but inhibited by neutral ambient pH, and transcripts encoding the endopolygalacturonase gene pg1 accumulated maximally under acidic culture conditions. We cloned a putative transcription factor-encoding gene, pac1, that may participate in a molecular signaling pathway for regulating gene expression in response to ambient pH. The three zinc finger domains of the predicted Pac1 protein are similar in sequence and organization to the zinc finger domains of the A. nidulans pH-responsive transcription factor PacC. The promoter of pac1 contains eight PacC consensus binding sites, suggesting that this gene, like its homologs, is autoregulated. Consistent with this suggestion, the accumulation of pac1 transcripts paralleled increases in ambient pH. Pac1 was determined to be a functional homolog of PacC by complementation of an A. nidulans pacC-null strain with pac1. Our results suggest that ambient pH is a regulatory cue for processes linked to pathogenicity, development, and virulence and that these processes may be under the molecular regulation of a conserved pH-dependent signaling pathway analogous to that in the nonpathogenic fungus A. nidulans. PMID:11133430

  14. Evolutionistic or revolutionary paths? A PACS maturity model for strategic situational planning.

    PubMed

    van de Wetering, Rogier; Batenburg, Ronald; Lederman, Reeva

    2010-07-01

    While many hospitals are re-evaluating their current Picture Archiving and Communication System (PACS), few have a mature strategy for PACS deployment. Furthermore, strategies for implementation, strategic and situational planning methods for the evolution of PACS maturity are scarce in the scientific literature. Consequently, in this paper we propose a strategic planning method for PACS deployment. This method builds upon a PACS maturity model (PMM), based on the elaboration of the strategic alignment concept and the maturity growth path concept previously developed in the PACS domain. First, we review the literature on strategic planning for information systems and information technology and PACS maturity. Secondly, the PMM is extended by applying four different strategic perspectives of the Strategic Alignment Framework whereupon two types of growth paths (evolutionistic and revolutionary) are applied that focus on a roadmap for PMM. This roadmap builds a path to get from one level of maturity and evolve to the next. An extended method for PACS strategic planning is developed. This method defines eight distinctive strategies for PACS strategic situational planning that allow decision-makers in hospitals to decide which approach best suits their hospitals' current situation and future ambition and what in principle is needed to evolve through the different maturity levels. The proposed method allows hospitals to strategically plan for PACS maturation. It is situational in that the required investments and activities depend on the alignment between the hospital strategy and the selected growth path. The inclusion of both strategic alignment and maturity growth path concepts make the planning method rigorous, and provide a framework for further empirical research and clinical practice.

  15. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2010-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4+27 kg m2 s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies revealed by geoid anomalies of the degree 4-10 packet of the Earth's spherical harmonic coefficients. These linear positive geoid anomalies underlie plate subduction zones and are presumed due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant

  16. DICOM-compliant PACS with CD-based image archival

    NASA Astrophysics Data System (ADS)

    Cox, Robert D.; Henri, Christopher J.; Rubin, Richard K.; Bret, Patrice M.

    1998-07-01

    This paper describes the design and implementation of a low- cost PACS conforming to the DICOM 3.0 standard. The goal was to provide an efficient image archival and management solution on a heterogeneous hospital network as a basis for filmless radiology. The system follows a distributed, client/server model and was implemented at a fraction of the cost of a commercial PACS. It provides reliable archiving on recordable CD and allows access to digital images throughout the hospital and on the Internet. Dedicated servers have been designed for short-term storage, CD-based archival, data retrieval and remote data access or teleradiology. The short-term storage devices provide DICOM storage and query/retrieve services to scanners and workstations and approximately twelve weeks of 'on-line' image data. The CD-based archival and data retrieval processes are fully automated with the exception of CD loading and unloading. The system employs lossless compression on both short- and long-term storage devices. All servers communicate via the DICOM protocol in conjunction with both local and 'master' SQL-patient databases. Records are transferred from the local to the master database independently, ensuring that storage devices will still function if the master database server cannot be reached. The system features rules-based work-flow management and WWW servers to provide multi-platform remote data access. The WWW server system is distributed on the storage, retrieval and teleradiology servers allowing viewing of locally stored image data directly in a WWW browser without the need for data transfer to a central WWW server. An independent system monitors disk usage, processes, network and CPU load on each server and reports errors to the image management team via email. The PACS was implemented using a combination of off-the-shelf hardware, freely available software and applications developed in-house. The system has enabled filmless operation in CT, MR and ultrasound within

  17. Utilisation of PACS to monitor patient CT doses.

    PubMed

    AlSuwaidi, J S; Bayoumi, M; Al Shibli, N; Sulaiman, H; Urrahman, T; AlYarah, M

    2011-09-01

    In the past 5 y, the number of computed tomography (CT) studies has doubled at Dubai Health Authority hospitals. This situation, along with patient's overdoses reported internationally, has prompted action to establish a system to manage patient doses incurred due to medical imaging practices. In this work, the authors aim to homogenise dose reporting to monitor radiation dose levels and facilitate the establishment of local and national dose reference levels. The two hospitals enrolled in this study are equipped with three CT systems (two 4 slices and one 64 slices). Through the Picture Archive and Communication Systems (PACS) tracking system, it is mandatory to fill CT patient doses in radiology information system (RIS). Dose length product (mGy cm) was recorded for 2502 adult and 178 paediatric patients. All patients' dosimetry data were collected from the RIS by Cogonos statistical software. The PACS data were reviewed to exclude incomplete data. Average and range of effective doses for adult and paediatric patients were calculated using an appropriate weighting factor. Individual accumulated effective doses for adult and paediatric patients were calculated for 4s-scanner-1 only. Adult average effective doses for the head (1482 exams) were 1.23 ± 0.58, 2.84 ± 0.83 and 2.98 ± 1.103 mSv, the chest (545 exams) were 5.39 ± 1.63, 21.85 ± 5.63 and 18.19 ± 3.22 mSv and for the abdomen and pelvis (1183 exams) were 10.85 ± 4.26, 25.66 ± 8.83 and 26.46 ± 13.75 mSv for 4s-scanner-1, 4s-scanner-2 and 64 s, respectively. The paediatric average effective dose for the head (127 exams) was 1.77 ± 0.82 mSv, for the chest (22 exams) was 3.3 ± 1.29 mSv and for the abdomen and pelvis (27 exams) was 6.16 ± 2.64 mSv. Results of individual accumulated effective doses for adult and paediatric patients were presented. PACS dose reporting facilitated dosimetry clinical auditing. Effective doses obtained in this work demonstrated that the results of one scanner were within

  18. Digital Light Box, One Of The Integral Pieces Of PACS

    NASA Astrophysics Data System (ADS)

    Rutherford, Harold G.; Gray, Michael J.

    1983-05-01

    A workable PACS system consists of several discrete assemblies which are linked together by data communication links for terminal and image data input and output. Two phases of development of a PACS system can be identified and labeled: emulation and enhancement. The latter is characterized by the observation "you do that so well, can you also do this?" Emulation, on the other hand, assures an accepted and working system. One of the key components of a PACS system is the emulation of the classical and ubiquitous "lightbox". This paper presents an emulation of the lightbox using a highspeed digital disk and video display on multiple high resolution monitors capable of 1024 x 1024 or 512 x 512 resolution pixel display. The emulation features are: a) loading and reloading in less than one second, b) access to between 800 and 3200 digital radiographs, and c) highspeed review forward and backward through this list of radiographs at rates up to 30 new images/second. Operation is under manual control both in rate and direction. This stresses the speed. The feature which makes this "lightbox" emulation desirable is the ability to dwell on a presently viewable display of digital radiographs with access to previous and following images in the study. One of the features desired in an emulation is that the components be "off the shelf". This means that existing hardware is used in the emulation. Software can then be generated based on known hardware. The emulation has flexibility of size: multi-image displays ranging from 2 or 3 images side by side to the piano-roll type endless display of an array with 4 images side-by-side and 3 rows visible at any one time. In addition, it has flexibility of resolution: radiographs displayable within a 256 x 256 pixel region to those displayable within a 1024 x 1024 pixel array as well as images which are much larger (4000 pixel by 4000 line chest radiograph scans) using a 1024 pixel by 1024 line window into the radiograph. The emulation of

  19. Two-axis angular effector

    DOEpatents

    Vaughn, Mark R.; Robinett, III, Rush D.; Phelan, John R.; Van Zuiden, Don M.

    1997-01-21

    A new class of coplanar two-axis angular effectors. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation.

  20. The tetrahexahedric angular Calogero model

    NASA Astrophysics Data System (ADS)

    Correa, Francisco; Lechtenfeld, Olaf

    2015-10-01

    The spherical reduction of the rational Calogero model (of type A n-1 and after removing the center of mass) is considered as a maximally superintegrable quantum system, which describes a particle on the ( n-2)-sphere subject to a very particular potential. We present a detailed analysis of the simplest non-separable case, n=4, whose potential is singular at the edges of a spherical tetrahexahedron. A complete set of independent conserved charges and of Hamiltonian intertwiners is constructed, and their algebra is elucidated. They arise from the ring of polynomials in Dunkl-deformed angular momenta, by classifying the subspaces invariant and antiinvariant under all Weyl reflections, respectively.

  1. Variable Distance Angular Symbology Reader

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F., Jr. (Inventor); Corder, Eric L. (Inventor)

    2006-01-01

    A variable distance angular symbology, reader utilizes at least one light source to direct light through a beam splitter and onto a target. A target may be angled relative to the impinging light beam up to and maybe even greater than 45deg. A reflected beam from the target passes through the beam splitter and is preferably directed 90deg relative to the light source through a telecentric lens to a scanner which records an image of the target such as a direct part marking code.

  2. Building and using a PACS in pathology and cytology

    NASA Astrophysics Data System (ADS)

    van Drunen, Rudi; van Teylingen, Geert; Boon, Mathilde E.; Kok, Lambrecht P.

    2001-08-01

    Applications of Picture Archiving and Communication Systems (PACS) in Pathology and Cytology are currently hardly used in the diagnostic process. Here we describe a system that, together with existing equipment, stores data from cervix smears, and aids the physician in the diagnostic process. The system comprises of a scanning system for the specimen and a multi-level storage system partly on disk and partly on optical media. The system adds additional benefits in the diagnostic process while at the same time provides a safe long-term storage and archive of the data. Due to the open nature and the cost-effectiveness of this solution applications of this system can be found not only in cervical cytology but also in pathology or other parts of medicine where image processing or storage is a major issue.

  3. Image fusion in open-architecture PACS-environment.

    PubMed

    Pohjonen, H

    2001-07-01

    Multimodal digital imaging is common in many fields of diagnosis and therapy planning - there is great interest in matching globally, fusing or registering data from the same part of the body. In practice, there are still difficulties in customizing image fusion in hospitals. Efficient routine use of image fusion requires, among others, an image management infrastructure - a picture archiving and communication system (PACS) - to provide storage of image data in a standard digital format, intelligent image management and fault-tolerant high-speed image networking. In order to customize image fusion, advances in both fusion software and hardware are also needed. The algorithms should be automatic, fast and accurate enough. Registration of multimodal data also creates a need for different display techniques and user-friendly interfaces. Image fusion has been impractical and too tedious to be performed in routine work, but in the future, fused images will be used in clinical practice - even in teleradiological consultation.

  4. Benefits of cloud computing for PACS and archiving.

    PubMed

    Koch, Patrick

    2012-01-01

    The goal of cloud-based services is to provide easy, scalable access to computing resources and IT services. The healthcare industry requires a private cloud that adheres to government mandates designed to ensure privacy and security of patient data while enabling access by authorized users. Cloud-based computing in the imaging market has evolved from a service that provided cost effective disaster recovery for archived data to fully featured PACS and vendor neutral archiving services that can address the needs of healthcare providers of all sizes. Healthcare providers worldwide are now using the cloud to distribute images to remote radiologists while supporting advanced reading tools, deliver radiology reports and imaging studies to referring physicians, and provide redundant data storage. Vendor managed cloud services eliminate large capital investments in equipment and maintenance, as well as staffing for the data center--creating a reduction in total cost of ownership for the healthcare provider.

  5. The PacCAF Grid portal for the CDF experiment

    NASA Astrophysics Data System (ADS)

    Hou, Suen

    Distributed computing for the CDF experiment has been developed and is evolving towards shared resources on the computing Grid. Dedicated CAFs (CDF Analysis Farm) were constructed on Condor pools with a suit of services for user authentication, software distribution, and network connection to worker nodes.With the Condor Glide-in mechanism, the CAFs are extended to using dynamic worker pools collected from the Grid. The PacCAF (Pacific CAF) is the Glide CAF thus built to provide a single point portal to LCG (LHC ComputingGrid) and OSG (Open Science Grid) sites in the Pacific Asia region. We discuss the implementation and service as a late-binding solution towards Grid computing.

  6. EAP hydrogels for pulse-actuated cell system (PACS) architectures

    NASA Astrophysics Data System (ADS)

    Plata, R. Erik; Rogers, Hallena R.; Banister, Mark; Vohnout, Sonia; McGrath, Dominic V.

    2007-04-01

    Electroactuated polymer (EAP) hydrogels based on JEFFAMINE® T-403 and ethylene glycol glycidyl ether (EGDGE) are used in an infusion pump based on the proprietary Pulse Actuated Cell System (PACS) architecture in development at Medipacs LLC. We report here significant progress in optimizing the formulation of the EAP hydrogels to dramatically increase hydrolytic stability and reproducibility of actuation response. By adjusting the mole fraction of reactive components of the formulation and substituting higher molecular weight monomers, we eliminated a large degree of the hydrolytic instability of the hydrogels, decreased the brittleness of the gel, and increased the equilibrium swelling ratio. The combination of these two modifications to the formulation resulted in hydrogels that exhibited reproducible swelling and deswelling in response to pH for a total period of 10-15 hours.

  7. Proceedings of the 22nd Particle Accelerator Conference (PAC'07)

    SciTech Connect

    N /A

    2007-08-01

    The twenty-second Particle Accelerator Conference, PAC'07, took place at the Albuquerque Convention Centre in Albuquerque, the largest city in New Mexico, from Monday to Friday, 2007 June 25 to 29. It was attended by over 1350 delegates from 25 different countries (63% North America, 24% Europe, 11% Asia and 2% Other), and was held under the auspices of the two professional societies that oversee and make holding this series of conferences possible, the Division of Physics of Beams within APS, and the Nuclear and Plasma Sciences Society within IEEE. As host of the conference, Los Alamos National Laboratory (LANL) is especially thanked for their many contributions and assistance both prior to and during the conference. The Convention Center was an ideal location for information sharing and discussions between the interdisciplinary aspects of the accelerator community, as well as for related meetings and ad-hoc 'rump' sessions.

  8. Clinical experiences with an ASP model backup archive for PACS images

    NASA Astrophysics Data System (ADS)

    Liu, Brent J.; Cao, Fei; Documet, Luis; Huang, H. K.; Muldoon, Jean

    2003-05-01

    Last year we presented a Fault-Tolerant Backup Archive using an Application Service Provider (ASP) model for disaster recovery. The purpose of this paper is to update and provide clinical experiences related towards implementing the ASP model archive solution for short-term backup of clinical PACS image data as well as possible applications other than disaster recovery. The ASP backup archive provides instantaneous, automatic backup of acquired PACS image data and instantaneous recovery of stored PACS image data all at a low operational cost and with little human intervention. This solution can be used for a variety of scheduled and unscheduled downtimes that occur on the main PACS archive. A backup archive server with hierarchical storage was implemented offsite from the main PACS archive location. Clinical data from a hospital PACS is sent to this ASP storage server in parallel to the exams being archived in the main server. Initially, connectivity between the main archive and the ASP storage server is established via a T-1 connection. In the future, other more cost-effective means of connectivity will be researched such as the Internet 2. We have integrated the ASP model backup archive with a clinical PACS at Saint John's Health Center and has been operational for over 6 months. Pitfalls encountered during integration with a live clinical PACS and the impact to clinical workflow will be discussed. In addition, estimations of the cost of establishing such a solution as well as the cost charged to the users will be included. Clinical downtime scenarios, such as a scheduled mandatory downtime and an unscheduled downtime due to a disaster event to the main archive, were simulated and the PACS exams were sent successfully from the offsite ASP storage server back to the hospital PACS in less than 1 day. The ASP backup archive was able to recover PACS image data for comparison studies with no complex operational procedures. Furthermore, no image data loss was

  9. Controlling neutron orbital angular momentum.

    PubMed

    Clark, Charles W; Barankov, Roman; Huber, Michael G; Arif, Muhammad; Cory, David G; Pushin, Dmitry A

    2015-09-24

    The quantized orbital angular momentum (OAM) of photons offers an additional degree of freedom and topological protection from noise. Photonic OAM states have therefore been exploited in various applications ranging from studies of quantum entanglement and quantum information science to imaging. The OAM states of electron beams have been shown to be similarly useful, for example in rotating nanoparticles and determining the chirality of crystals. However, although neutrons--as massive, penetrating and neutral particles--are important in materials characterization, quantum information and studies of the foundations of quantum mechanics, OAM control of neutrons has yet to be achieved. Here, we demonstrate OAM control of neutrons using macroscopic spiral phase plates that apply a 'twist' to an input neutron beam. The twisted neutron beams are analysed with neutron interferometry. Our techniques, applied to spatially incoherent beams, demonstrate both the addition of quantum angular momenta along the direction of propagation, effected by multiple spiral phase plates, and the conservation of topological charge with respect to uniform phase fluctuations. Neutron-based studies of quantum information science, the foundations of quantum mechanics, and scattering and imaging of magnetic, superconducting and chiral materials have until now been limited to three degrees of freedom: spin, path and energy. The optimization of OAM control, leading to well defined values of OAM, would provide an additional quantized degree of freedom for such studies.

  10. Discrete Newtonian cosmology: perturbations

    NASA Astrophysics Data System (ADS)

    Ellis, George F. R.; Gibbons, Gary W.

    2015-03-01

    In a previous paper (Gibbons and Ellis 2014 Discrete Newtonian cosmology Class. Quantum Grav. 31 025003), we showed how a finite system of discrete particles interacting with each other via Newtonian gravitational attraction would lead to precisely the same dynamical equations for homothetic motion as in the case of the pressure-free Friedmann-Lemaître-Robertson-Walker cosmological models of general relativity theory, provided the distribution of particles obeys the central configuration equation. In this paper we show that one can obtain perturbed such Newtonian solutions that give the same linearized structure growth equations as in the general relativity case. We also obtain the Dmitriev-Zel’dovich equations for subsystems in this discrete gravitational model, and show how it leads to the conclusion that voids have an apparent negative mass.

  11. Conformal perturbation theory

    NASA Astrophysics Data System (ADS)

    Amoretti, Andrea; Magnoli, Nicodemo

    2017-08-01

    Statistical systems near a classical critical point have been intensively studied from both theoretical and experimental points of view. In particular, correlation functions are of relevance in comparing theoretical models with the experimental data of real systems. In order to compute physical quantities near a critical point, one needs to know the model at the critical (conformal) point. In this line, recent progress in the knowledge of conformal field theories, through the conformal bootstrap, gives the hope of getting some interesting results also outside of the critical point. In this paper, we will review and clarify how, starting from the knowledge of the critical correlators, one can calculate in a safe way their behavior outside the critical point. The approach illustrated requires the model to be just scale invariant at the critical point. We will clarify the method by applying it to different kind of perturbations of the 2D Ising model.

  12. Separability of Gravitational Perturbation in Generalized Kerr-Nut Sitter Space-Time

    NASA Astrophysics Data System (ADS)

    Oota, Takeshi; Yasui, Yukinori

    Generalized Kerr-NUT-de Sitter space-time is the most general space-time which admits a rank-2 closed conformal Killing-Yano tensor. It contains the higher-dimensional Kerr-de Sitter black holes with partially equal angular momenta. We study the separability of gravitational perturbations in the generalized Kerr-NUT-de Sitter space-time. We show that a certain type of tensor perturbations admits the separation of variables. The linearized perturbation equations for the Einstein condition are transformed into the ordinary differential equations of Fuchs type.

  13. Perturbed effects at radiation physics

    NASA Astrophysics Data System (ADS)

    Külahcı, Fatih; Şen, Zekâi

    2013-09-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer-Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables.

  14. Perturbing a quantum gravity condensate

    NASA Astrophysics Data System (ADS)

    Gielen, Steffen

    2015-02-01

    In a recent proposal using the group field theory approach, a spatially homogeneous (generally anisotropic) universe is described as a quantum gravity condensate of "atoms of space," which allows the derivation of an effective cosmological Friedmann equation from the microscopic quantum gravity dynamics. Here we take a first step towards the study of cosmological perturbations over the homogeneous background. We consider a state in which a single "atom" is added to an otherwise homogeneous condensate. Backreaction of the perturbation on the background is negligible and the background dynamics can be solved separately. The dynamics for the perturbation takes the form of a quantum cosmology Hamiltonian for a "wave function," depending on background and perturbations, of the product form usually assumed in a Born-Oppenheimer approximation. We show that the perturbation we consider corresponds to a spatially homogeneous metric perturbation, and for this case derive the usual procedures in quantum cosmology from fundamental quantum gravity.

  15. Hybrid perturbation scheme for wide beamwidth circularly polarized stacked patch microstrip antenna for satellite communication

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Shakawat

    Circularly polarized microstrip antennas are popular for satellite communications due to their circularly polarized orientation. They are used frequently in modern day satellite communication. In order to achieve wide angular coverage in satellite communication, a wide beamwidth is required from the antenna. Traditional single layer microstrip antenna inherently demonstrates low angular beamwidth of approximately 600 to 800and thereby lacks wide angular coverage when used for satellite communication. The objective of this thesis is to design a single-fed stacked microstrip antenna using different perturbation techniques in order to achieve a wide angular beamwidth. This thesis presents a new design for a circularly polarized antenna based on the hybrid perturbation scheme. First, a method of stacked patch-ring with negative perturbation was used to generate a significantly larger beamwidth of 1060. The axial ratio (AR) bandwidth obtained is also significantly larger compared to the case when square rings are used as parasitic and driven rings with a single feed. A simulated impedance bandwidth (S11< - 10 dB) of 16%, 3 dB AR bandwidth of 8% and a peak gain of 8.65 dBic are obtained from this design. Next, a new design of stacked hybrid antenna is presented, which uses hybrid perturbations to generate circular polarization radiation. An enhanced beamwidth of 1260 was obtained. The simulation results are confirmed by the measured results.

  16. Distribution of aluminum species and the characteristics of structure of poly-aluminum-chloride-sulfate(PACS).

    PubMed

    Gao, B Y; Yue, Q Y; Yu, H; Wang, Y

    2001-01-01

    A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO4(2-) molar ratio, has been prepared and dried at 105 degrees C and 65 degrees C, respectively. The distribution of aluminum species of PACS was examined, and the effect of gamma value, Al3+/SO4(2-) molar ratio, dilution on the distribution of aluminum species of PACS was also investigated by using Alferron timed complex colorimetric method. The IR spectroscopy and X-ray diffraction were used to study the effect of gamma value, Al3+/SO4(2-) molar ratio and the drying temperature on the structure of PACS. The experimental results show that Al3+/SO4(2-) molar ratio has a great effect on the distribution of aluminum species, but the dilution has a little effect on the distribution of aluminum species. The lower the Al3+/SO4(2-) molar ratio, the higher the proportions of the polymer and colloidal species in PACS. The polymeric degree of PACS was related to gamma value and Al3+/SO4(2-) molar ratio. Drying temperature has an influence on the structure and the solubility of solid PACS products.

  17. Design and implementation of GRID-based PACS in a hospital with multiple imaging departments

    NASA Astrophysics Data System (ADS)

    Yang, Yuanyuan; Jin, Jin; Sun, Jianyong; Zhang, Jianguo

    2008-03-01

    Usually, there were multiple clinical departments providing imaging-enabled healthcare services in enterprise healthcare environment, such as radiology, oncology, pathology, and cardiology, the picture archiving and communication system (PACS) is now required to support not only radiology-based image display, workflow and data flow management, but also to have more specific expertise imaging processing and management tools for other departments providing imaging-guided diagnosis and therapy, and there were urgent demand to integrate the multiple PACSs together to provide patient-oriented imaging services for enterprise collaborative healthcare. In this paper, we give the design method and implementation strategy of developing grid-based PACS (Grid-PACS) for a hospital with multiple imaging departments or centers. The Grid-PACS functions as a middleware between the traditional PACS archiving servers and workstations or image viewing clients and provide DICOM image communication and WADO services to the end users. The images can be stored in distributed multiple archiving servers, but can be managed with central mode. The grid-based PACS has auto image backup and disaster recovery services and can provide best image retrieval path to the image requesters based on the optimal algorithms. The designed grid-based PACS has been implemented in Shanghai Huadong Hospital and been running for two years smoothly.

  18. Impact of PACS on the education of radiology residents: the residents' perspective.

    PubMed

    Mullins, M E; Mehta, A; Patel, H; McLoud, T C; Novelline, R A

    2001-01-01

    Because digital imaging and the picture archiving and communication system (PACS) are replacing radiographic film, the effect of PACS on residents' perceptions and their educational experience was investigated. Residents taking part in large diagnostic radiology training programs at two hospitals were surveyed. Approximately 75% of radiographic studies were reviewed with the use of PACS at both hospitals. Survey topics included technical and didactic issues based on direct and indirect comparison with analog (conventional film) images. Fifty residents were polled (20 respondents). The majority has been using PACS for more than 1 year (14 of 20, 70%) to interpret 75%-100% of cases (11 of 20, 55%). The majority believed that PACS improved patient care (15 of 20, 75%) and their educational experience (15 of 20, 75%). A minority believed that increased patient throughput was harmful to the educational experience (five of 20, 25%) because it permitted attending radiologists to review cases too quickly (four of 20, 20%). Residents favored PACS over hard-copy images for ease of manipulation, resolution, and ability to see pathologic conditions and normal anatomic characteristics. Residents believe that PACS has positively affected their learning experience and does not negatively affect the quality of resident education.

  19. Cosmological perturbations in massive bigravity

    SciTech Connect

    Lagos, Macarena; Ferreira, Pedro G. E-mail: p.ferreira1@physics.ox.ac.uk

    2014-12-01

    We present a comprehensive analysis of classical scalar, vector and tensor cosmological perturbations in ghost-free massive bigravity. In particular, we find the full evolution equations and analytical solutions in a wide range of regimes. We show that there are viable cosmological backgrounds but, as has been found in the literature, these models generally have exponential instabilities in linear perturbation theory. However, it is possible to find stable scalar cosmological perturbations for a very particular choice of parameters. For this stable subclass of models we find that vector and tensor perturbations have growing solutions. We argue that special initial conditions are needed for tensor modes in order to have a viable model.

  20. Wireless-PDA-controlled image workflow from PACS: the next trend in the health care enterprise?

    NASA Astrophysics Data System (ADS)

    Erberich, Stephan G.; Documet, Jorge; Zhou, Michael Z.; Cao, Fei; Liu, Brent J.; Mogel, Greg T.; Huang, H. K.

    2003-05-01

    Image workflow in today's Picture Archiving and Communication Systems (PACS) is controlled from fixed Display Workstations (DW) using proprietary control interfaces. A remote access to the Hospital Information System (HIS) and Radiology Information System (RIS) for urgent patient information retrieval does not exist or gradually become available. The lack for remote access and workflow control for HIS and RIS is especially true when it comes to medical images of a PACS on Department or Hospital level. As images become more complex and data sizes expand rapidly with new image techniques like functional MRI, Mammography or routine spiral CT to name a few, the access and manageability becomes an important issue. Long image downloads or incomplete work lists cannot be tolerated in a busy health care environment. In addition, the domain of the PACS is no longer limited to the imaging department and PACS is also being used in the ER and emergency care units. Thus a prompt and secure access and manageability not only by the radiologist, but also from the physician becomes crucial to optimally utilize the PACS in the health care enterprise of the new millennium. The purpose of this paper is to introduce a concept and its implementation of a remote access and workflow control of the PACS combining wireless, Internet and Internet2 technologies. A wireless device, the Personal Digital Assistant (PDA), is used to communicate to a PACS web server that acts as a gateway controlling the commands for which the user has access to the PACS server. The commands implemented for this test-bed are query/retrieve of the patient list and study list including modality, examination, series and image selection and pushing any list items to a selected DW on the PACS network.

  1. PACS in the Utrecht University Hospital: final conclusions of the clinical evaluation

    NASA Astrophysics Data System (ADS)

    Wilmink, J. B.; ter Haar Romeny, Bart M.; Barneveld Binkhuysen, Frits H.; Achterberg, A. J.; Zuiderveld, Karel J.; Calkoen, P.; Kouwenberg, Jef M.

    1990-08-01

    In the past three years, a clinical evaluation of a PACS has been performed in the Utrecht University Hospital as part of the Dutch PACS project. The clinical evaluation focussed on the following aspects: technical evaluation of the prototype PACS equipment coupled to the HIS; diagnostic accuracy studies; studies concerning the impact on the organization of the radiology-department and the referring wards; and cost-savings analysis. Some of the results of these subprojects have already been presented at previous SPIE conferences. In this paper the general condusions are presented about the usefulness of the evaluated PAC-System in the daily routine of radiology department and clinic. By making available the images of radiological examinations fast, complete, reliable and continously on the ward, concrete improvements with regard to the current process could be realized. The possibilities of PACS caused an increasing enthousiasm among the clinicians. By the easier access to all images of their patients during 24 hours/day, they saw more images on the day of the examination and images could be more easily used at consultations of other specialists. The overall conclusion is positive, but a lot of work has to be done to transform PACS from an experimental setup into a routine production system on which a flimless hospital can be based. A complete PACS needs an inteffigent Image Management System, which indudes prefetching algorithms based on data from the Hospital Information System and automated procedures for removing obsolete images from the local buffers in the workstations. As yet PACS is very expensive, and the direct savings in the hospital cannot compensate for the high costs of investment. Possibly PACS can contribute to a shorter stay of patients in the hospital. This will lead to savings for government and health insurance companies and they can be expected to contribute to PAS implementation studies.

  2. Angular Positioning Sensor for Space Mechanisms

    NASA Astrophysics Data System (ADS)

    Steiner, Nicolas; Chapuis, Dominique

    2013-09-01

    Angular position sensors are used on various rotating mechanisms such as solar array drive mechanisms, antenna pointing mechanisms, scientific instruments, motors or actuators.Now a days, potentiometers and encoders are mainly used for angular measurement purposes. Both of them have their own pros and cons.As alternative, Ruag Space Switzerland Nyon (RSSN) is developing and qualifying two innovative technologies of angular position sensors which offer easy implementation, medium to very high lifetime and high flexibility with regards to the output signal shape/type.The Brushed angular position sensor uses space qualified processes which are already flying on RSSN's sliprings for many years. A large variety of output signal shape can be implemented to fulfill customer requirements (digital, analog, customized, etc.).The contactless angular position sensor consists in a new radiation hard Application Specific Integrated Circuit (ASIC) based on the Hall effect and providing the angular position without complex processing algorithm.

  3. Sphere-pac fuel development program. First semi-annual progress report, October 1979-March 1980

    SciTech Connect

    Felt, R.E.

    1980-05-01

    Development of processes by Exxon Nuclear Company, Inc. for fabricating spherical particle nuclear fuel (sphere-pac) during October 1979 through March 1980 is reported. The program surveyed available technology to develop an initial flowsheet as a design basis for process development. An 0.1 ton/day pilot plant was built to develop and demonstrate the fabrication of sphere-pac fuel. Process and equipment efforts have been directed towards the demonstration of processes and equipment necessary to fabricate sphere-pac fuel on a commercial scale.

  4. PAC learning using Nadaraya-Watson estimator based on orthonormal systems

    SciTech Connect

    Qiao, Hongzhu; Rao, N.S.V.; Protopopescu, V.

    1997-08-01

    Regression or function classes of Euclidean type with compact support and certain smoothness properties are shown to be PAC learnable by the Nadaraya-Watson estimator based on complete orthonormal systems. While requiring more smoothness properties than typical PAC formulations, this estimator is computationally efficient, easy to implement, and known to perform well in a number of practical applications. The sample sizes necessary for PAC learning of regressions or functions under sup norm cost are derived for a general orthonormal system. The result covers the widely used estimators based on Haar wavelets, trignometric functions, and Daubechies wavelets.

  5. Surgical PACS for the digital operating room. Systems engineering and specification of user requirements.

    PubMed

    Korb, Werner; Bohn, Stefan; Burgert, Oliver; Dietz, Andreas; Jacobs, Stephan; Falk, Volkmar; Meixensberger, Jürgen; Strauss, Gero; Trantakis, Christos; Lemke, Heinz U

    2006-01-01

    For better integration of surgical assist systems into the operating room, a common communication and processing plattform that is based on the users needs is needed. The development of such a system, a Surgical Picture Aquisition and Communication System (S-PACS), according the systems engineering cycle is oulined in this paper. The first two steps (concept and specification) for the engineering of the S-PACS are discussed.A method for the systematic integration of the users needs', the Quality Function Deployment (QFD), is presented. The properties of QFD for the underlying problem and first results are discussed. Finally, this leads to a first definition of an S-PACS system.

  6. Oral candidiasis and angular cheilitis.

    PubMed

    Sharon, Victoria; Fazel, Nasim

    2010-01-01

    Candidiasis, an often encountered oral disease, has been increasing in frequency. Most commonly caused by the overgrowth of Candida albicans, oral candidiasis can be divided into several categories including acute and chronic forms, and angular cheilitis. Risk factors for the development of oral candidiasis include immunosuppression, wearing of dentures, pharmacotherapeutics, smoking, infancy and old age, endocrine dysfunction, and decreased salivation. Oral candidiasis may be asymptomatic. More frequently, however, it is physically uncomfortable, and the patient may complain of burning mouth, dysgeusia, dysphagia, anorexia, and weight loss, leading to nutritional deficiency and impaired quality of life. A plethora of antifungal treatments are available. The overall prognosis of oral candidiasis is good, and rarely is the condition life threatening with invasive or recalcitrant disease.

  7. GPDs and Orbital Angular Momentum

    NASA Astrophysics Data System (ADS)

    Burkardt, Matthias

    2017-05-01

    Generalized Parton Distributions provide information on the distribution of quarks in impact parameter space. For transversely polarized nucleons, these impact parameter distributions are transversely distorted and this deviation from axial symmetry leads on average to a net transverse force from the spectators on the active quark in a DIS experiment. This force when acting along the whole trajectory of the active quark leads to transverse single-spin asymmetries. For a longitudinally polarized nucleon target, the transverse force implies a torque acting on the quark Orbital Angular Momentum (OAM). The resulting change in OAM as the quark leaves the target equals the difference between the Jaffe-Manohar and Ji OAMs. In the context of the scalar diquark model we demonstrate that the effect from that torque contributes at the same order as single-spin asymmetries.

  8. Electrophoretic nature and evaluation of poly-aluminum-chloride-sulfate (PACS) as a coagulant for water and wastewater treatment.

    PubMed

    Gao, Bao-yu; Yue, Qin-yan; Wang, Bing-jian

    2003-05-01

    A series of poly-aluminum-chloride-sulfates (PACS), which have different OH/Al (gamma) and Al(3+)/SO4(2-) mole ratios, has been prepared using AlCl3 x 6H2O, A(SO4)3 x 18H2O and Na2CO3 as raw materials. The electrophoretic nature of PACS was investigated by electrophoresis. Laboratory experiments were undertaken to evaluate the PACS in comparison with polyaluminum chloride (PAC) for the coagulation of simulating water and actual wastewaters. The experimental results show that the gamma value and the Al(3+)/SO4(2-) mole ratio affect the electrophoretic nature of PACS. PACS has a maximum zeta potential at about a gamma value of 1.5 and Al(3+)/SO4(2-) mole ratio of 12-16. The zeta potential of PACS varies with pH. The performance of PACS as coagulant is affected by gamma value and Al(3+)/SO4(2-) mole ratio. PACS of gamma = 2.1 and Al(3+)/SO4(2-) = 15 gives best turbidity removal effectiveness. In comparison with PAC of gamma = 2.0, PACS of gamma = 2.0 and Al(3+)/SO4(2-) = 16 gives higher removal efficiency for turbidity and COD, and shows the following advantages in the clarification of waters and wastewaters: rapid aggregation velocity, larger and heavier flocs, and lower required dosage.

  9. Chirality and the angular momentum of light.

    PubMed

    Cameron, Robert P; Götte, Jörg B; Barnett, Stephen M; Yao, Alison M

    2017-02-28

    Chirality is exhibited by objects that cannot be rotated into their mirror images. It is far from obvious that this has anything to do with the angular momentum of light, which owes its existence to rotational symmetries. There is nevertheless a subtle connection between chirality and the angular momentum of light. We demonstrate this connection and, in particular, its significance in the context of chiral light-matter interactions.This article is part of the themed issue 'Optical orbital angular momentum'.

  10. Chirality and the angular momentum of light

    NASA Astrophysics Data System (ADS)

    Cameron, Robert P.; Götte, Jörg B.; Barnett, Stephen M.; Yao, Alison M.

    2017-02-01

    Chirality is exhibited by objects that cannot be rotated into their mirror images. It is far from obvious that this has anything to do with the angular momentum of light, which owes its existence to rotational symmetries. There is nevertheless a subtle connection between chirality and the angular momentum of light. We demonstrate this connection and, in particular, its significance in the context of chiral light-matter interactions. This article is part of the themed issue 'Optical orbital angular momentum'.

  11. Orbital angular momentum in phase space

    SciTech Connect

    Rigas, I.; Sanchez-Soto, L.L.; Klimov, A.B.; Rehacek, J.; Hradil, Z.

    2011-02-15

    Research Highlights: > We propose a comprehensive Weyl-Wigner formalism for the canonical pair angle-angular momentum. > We present a simple and useful toolkit for the practitioner. > We derive simple evolution equations in terms of a star product in the semiclassical limit. - Abstract: A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented. Special attention is paid to the problems linked to rotational periodicity and angular-momentum discreteness.

  12. Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus

    PubMed Central

    Cardoso, João CR; de Vet, Edwin CJM; Louro, Bruno; Elgar, Greg; Clark, Melody S; Power, Deborah M

    2007-01-01

    Background: Duplicated genes are common in vertebrate genomes. Their persistence is assumed to be either a consequence of gain of novel function (neofunctionalisation) or partitioning of the function of the ancestral molecule (sub-functionalisation). Surprisingly few studies have evaluated the extent of such modifications despite the numerous duplicated receptor and ligand genes identified in vertebrate genomes to date. In order to study the importance of function in the maintenance of duplicated genes, sea bream (Sparus auratus) PAC1 receptors, sequence homologues of the mammalian receptor specific for PACAP (Pituitary Adenylate Cyclase-Activating Polypeptide), were studied. These receptors belong to family 2 GPCRs and most of their members are duplicated in teleosts although the reason why both persist in the genome is unknown. Results: Duplicate sea bream PACAP receptor genes (sbPAC1A and sbPAC1B), members of family 2 GPCRs, were isolated and share 77% amino acid sequence identity. RT-PCR with specific primers for each gene revealed that they have a differential tissue distribution which overlaps with the distribution of the single mammalian receptor. Furthermore, in common with mammals, the teleost genes undergo alternative splicing and a PAC1Ahop1 isoform has been characterised. Duplicated orthologous receptors have also been identified in other teleost genomes and their distribution profile suggests that function may be species specific. Functional analysis of the paralogue sbPAC1s in Cos7 cells revealed that they are strongly stimulated in the presence of mammalian PACAP27 and PACAP38 and far less with VIP (Vasoactive Intestinal Peptide). The sbPAC1 receptors are equally stimulated (LOGEC50 values for maximal cAMP production) in the presence of PACAP27 (-8.74 ± 0.29 M and -9.15 ± 0.21 M, respectively for sbPAC1A and sbPAC1B, P > 0.05) and PACAP38 (-8.54 ± 0.18 M and -8.92 ± 0.24 M, respectively for sbPAC1A and sbPAC1B, P > 0.05). Human VIP was found to

  13. Perturbation of a Schwarzschild Black Hole Due to a Rotating Thin Disk

    NASA Astrophysics Data System (ADS)

    Čížek, P.; Semerák, O.

    2017-09-01

    Will, in 1974, treated the perturbation of a Schwarzschild black hole due to a slowly rotating, light, concentric thin ring by solving the perturbation equations in terms of a multipole expansion of the mass-and-rotation perturbation series. In the Schwarzschild background, his approach can be generalized to perturbation by a thin disk (which is more relevant astrophysically), but, due to rather bad convergence properties, the resulting expansions are not suitable for specific (numerical) computations. However, we show that Green’s functions, represented by Will’s result, can be expressed in closed form (without multipole expansion), which is more useful. In particular, they can be integrated out over the source (a thin disk in our case) to yield good converging series both for the gravitational potential and for the dragging angular velocity. The procedure is demonstrated, in the first perturbation order, on the simplest case of a constant-density disk, including the physical interpretation of the results in terms of a one-component perfect fluid or a two-component dust in a circular orbit about the central black hole. Free parameters are chosen in such a way that the resulting black hole has zero angular momentum but non-zero angular velocity, as it is just carried along by the dragging effect of the disk.

  14. Drell-Yan Angular Distributions at the E906 SeaQuest Experiment

    NASA Astrophysics Data System (ADS)

    Kleinjan, David

    2016-09-01

    Measurement of Drell-Yan angular distributions in the Collins-Soper frame provide a unique study of QCD. Previous experimental results showed a violation of the Lam-Tung relation (1 - λ ≠ 2 ν). This violation could be described by a range of non-perturbative effects, including the naive T-odd Boer-Mulders TMD, which describes spin-momentum correlations in the nucleon. Presently, E906/SeaQuest experiment at Fermilab can measure Drell-Yan dimuon pairs produced from a 120 GeV unpolarized proton beam directed on various nuclear targets. The Drell-Yan angular distributions will be measured at higher-x than previous experiments, further disentangling the role the Boer-Mulders TMD and other non-perturbative effects play in the structure of the nucleon. SeaQuest.

  15. Angular correlations in three-jet events in ep collisions at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bołd, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Corso, F. Dal; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bołd, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlański, W.; Perrey, H.; Piotrzkowski, K.; Pluciński, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycień, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolkapli, Z.; Zolko, M.; Zotkin, D. S.

    2012-03-01

    Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the final state and the proton-beam direction. These correlations provide a stringent test of perturbative QCD and show sensitivity to the contributions from different color configurations. Fixed-order perturbative calculations assuming the values of the color factors CF, CA, and TF as derived from a variety of gauge groups were compared to the measurements to study the underlying gauge group symmetry. The measured angular correlations in the deep inelastic ep scattering and photoproduction regimes are consistent with the admixture of color configurations as predicted by SU(3) and disfavour other symmetry groups, such as SU(N) in the limit of large N.

  16. The Angular Momentum of the Solar System

    NASA Astrophysics Data System (ADS)

    Cang, Rongquin; Guo, Jianpo; Hu, Juanxiu; He, Chaoquiong

    2016-05-01

    The angular momentum of the Solar System is a very important physical quantity to the formation and evolution of the Solar System. Previously, the spin angular momentum of the Sun and the orbital angular momentum of the Eight Giant Planets were only taken into consideration, when researchers calculated the angular momentum of the Solar System. Nowadays, it seems narrow and conservative. Using Eggleton's code, we calculate the rotational inertia of the Sun. Furthermore, we obtain that the spin angular momentum of the Sun is 1.8838 x 10^41 kg m^2 s^-1. Besides the spin angular momentum of the Sun and the orbital angular momentum of the Eight Giant Planets, we also account for the orbital angular momentum of the Asteroid Belt, the Kuiper Belt, the Oort Cloud, the Ninth Giant Planet and the Solar Companion. We obtain that the angular momentum of the whole Solar System is 3.3212 x 10^45 kg m^2 s^-1.

  17. Exponential time-dependent perturbation theory in rotationally inelastic scattering

    NASA Astrophysics Data System (ADS)

    Cross, R. J.

    1983-08-01

    An exponential form of time-dependent perturbation theory (the Magnus approximation) is developed for rotationally inelastic scattering. A phase-shift matrix is calculated as an integral in time over the anisotropic part of the potential. The trajectory used for this integral is specified by the diagonal part of the potential matrix and the arithmetic average of the initial and final velocities and the average orbital angular momentum. The exponential of the phase-shift matrix gives the scattering matrix and the various cross sections. A special representation is used where the orbital angular momentum is either treated classically or may be frozen out to yield the orbital sudden approximation. Calculations on Ar+N2 and Ar+TIF show that the theory generally gives very good agreement with accurate calculations, even where the orbital sudden approximation (coupled-states) results are seriously in error.

  18. Perturbative construction of stationary Randall-Sundrum II black holes on a 5-brane

    NASA Astrophysics Data System (ADS)

    Stein, Maren

    2016-09-01

    We numerically construct large Randall-Sundrum II brane black holes in 4 and 5 dimensions from associated AdS/CFT spacetimes. Our solutions are leading order perturbations of a representative of the boundary conformal structure of the AdS spacetime sourced by the dual CFT stress tensor. The 4-dimensional solutions are static perturbations of the Euclidean Schwarzschild metric, while the 5-dimensional solutions are perturbations of the Myers-Perry metric with equal angular momenta. We compare the former with previous numerical results for Randall-Sundrum bulk black holes and find good agreement down to a horizon radius of about r H ˜ 30ℓ. The latter are the first numerical results pertaining to rotating Randall-Sundrum black holes. They have the same entropy, but a larger horizon area than Myers-Perry black holes of the same mass and angular momentum.

  19. Thermal perturbation of the Sun

    NASA Technical Reports Server (NTRS)

    Twigg, L. W.; Endal, A. S.

    1982-01-01

    Thermal perturbations of the solar convection zone can be modeled (to the first order) by perturbing the mixing length parameter alpha (equal to the ratio of the mixing length to the pressure scale height) used in the standard mixing length theory of convection. Results of such an analysis are presented and discussed in relation to recent work by others.

  20. On dark energy isocurvature perturbation

    SciTech Connect

    Liu, Jie; Zhang, Xinmin; Li, Mingzhe E-mail: limz@nju.edu.cn

    2011-06-01

    Determining the equation of state of dark energy with astronomical observations is crucially important to understand the nature of dark energy. In performing a likelihood analysis of the data, especially of the cosmic microwave background and large scale structure data the dark energy perturbations have to be taken into account both for theoretical consistency and for numerical accuracy. Usually, one assumes in the global fitting analysis that the dark energy perturbations are adiabatic. In this paper, we study the dark energy isocurvature perturbation analytically and discuss its implications for the cosmic microwave background radiation and large scale structure. Furthermore, with the current astronomical observational data and by employing Markov Chain Monte Carlo method, we perform a global analysis of cosmological parameters assuming general initial conditions for the dark energy perturbations. The results show that the dark energy isocurvature perturbations are very weakly constrained and that purely adiabatic initial conditions are consistent with the data.

  1. Perturbation theory in electron diffraction

    NASA Astrophysics Data System (ADS)

    Bakken, L. N.; Marthinsen, K.; Hoeier, R.

    1992-12-01

    The Bloch-wave approach is used for discussing multiple inelastic electron scattering and higher-order perturbation theory in inelastic high-energy electron diffraction. In contrast to previous work, the present work describes three-dimensional diffraction so that higher-order Laue zone (HOLZ) effects are incorporated. Absorption is included and eigenvalues and eigenvectors are calculated from a structure matrix with the inclusion of an absorptive potential. Centrosymmetric as well as non-centrosymmetric crystal structures are allowed. An iteration method with a defined generalized propagation function for solving the inelastic coupling equations is described. It is shown that a similar iteration method with the same propagation function can be used for obtaining higher-order perturbation terms for the wave-function when a perturbation is added to the crystal potential. Finally, perturbation theory by matrix calculations when a general perturbation is added to the structure matrix is considered.

  2. Computing singularities of perturbation series

    SciTech Connect

    Kvaal, Simen; Jarlebring, Elias; Michiels, Wim

    2011-03-15

    Many properties of current ab initio approaches to the quantum many-body problem, both perturbational and otherwise, are related to the singularity structure of the Rayleigh-Schroedinger perturbation series. A numerical procedure is presented that in principle computes the complete set of singularities, including the dominant singularity which limits the radius of convergence. The method approximates the singularities as eigenvalues of a certain generalized eigenvalue equation which is solved using iterative techniques. It relies on computation of the action of the Hamiltonian matrix on a vector and does not rely on the terms in the perturbation series. The method can be useful for studying perturbation series of typical systems of moderate size, for fundamental development of resummation schemes, and for understanding the structure of singularities for typical systems. Some illustrative model problems are studied, including a helium-like model with {delta}-function interactions for which Moeller-Plesset perturbation theory is considered and the radius of convergence found.

  3. The Setup Of A Clinical Evaluation Of A Pac System

    NASA Astrophysics Data System (ADS)

    Binkhuysen, F. H. B.; ter Haar Romeny, B. M.; Andriessen, J. H.; Achterberg, A. J.; Raymakers, J. A.; van Waes, P. F. G. M.; Zuiderveld, K. J.

    1988-06-01

    The goal in the setup of the clinical evaluation of the PACSystem in the University Hospital Utrecht (UUH) is to realize such a presentation of images, coupled to other patient information, that radiologists and applicants can make diagnoses more flexible, faster and more fruitful. Moreover we try to get insight in the way a PACSystem can solve the problems regarding the contempory way of working with respects to diagnoses and image information; i. e. problems related to archiving and loaning of pictures, which may lead to loss and long searching times, problems with respect to room for archive, the high costs of photographic material and the impossibility of post processing on film. For the evaluation studies the following points are of importance. a. the storage of digitized image information on magnetic disc and optical disc (DOR). Direct digital input is coming from e. g. CT. While conventional films are digitised with a scanner/digitizer (MARSCAN). The image information can be seen on several monitors at the same time (multi access), i.e via MARVIEW in the digital reading room and a viewing station on the clinical ward. b. A coupling between the Hospital Information System (BAZIS) and PACS will be realized. c. The MARVIEW station offers several forms of image manipulation. In principle there is chosen for a complete PACS situation, that is to say that all information and procedures relating to the patients of a specific ward are manipulated up in the PACSystem. This specific ward is a clinical internal department and has fifteen beds. The data of this ward are compared to two comparable wards before and after installation of the PACSystem. Crucial is that in this situation we deal with a real operating clinical ward. To evaluate the effects of the introduction of such a PACSystem on diagnoses and organisation, a number of sub-projects are carried out in joint venture between the University Hospital Utrecht, BAZIS and PHILIPS. Two projects are especially of

  4. A Herschel-PACS view of 16 Centaurs

    NASA Astrophysics Data System (ADS)

    Duffard, Rene; Pinilla-Alonso, N.; Santos-Sanz, P.; Vilenius, E.; Ortiz, J.; Mueller, T.; Fornasier, S.; Lellouch, E.; Mommert, M.; Pal, A.; Kiss, C.; Mueller, M.; Stansberry, J.; Delsanti, A.; Peixinho, N.

    2013-10-01

    The goal of this work is to characterize a set of Centaurs in terms of their size, albedo, and thermal properties. The Herschel open time key program "TNOs are Cool!'' observed 130 Centaurs and TNOs in 2009-2012. In this particular work we use Herschel/PACS three-band photometry to obtain monochromatic flux densities at 70, 100 and 160 μm. Additionally, we also incorporate Spitzer/MIPS flux densities at 24 and 70 μm when available. We use a consistent method for data reduction and aperture photometry to finally determine sizes and albedos of 16 Centaurs using radiometric techniques. We study the correlations between the size and albedo resulting from our models and other physical (i.e spectral slope) and orbital parameters using a more extended sample (obtained from literature). The final sample comprises 36 objects: 18 Centaurs observed with Herschel/PACS; 10 observed only with Spitzer and 8 SDOs. The first conclusion is that the albedo of the Centaurs is not determined by their orbit. Similarly we do not find any correlation between diameter and orbital parameters. We also find that most of the objects in our sample are dark (pv < 7%) and most of them are small (D < 120km). However, we do not find any correlation between albedo and diameter, in particular for the group of the small objects we can find albedo values homogeneously distributed from 4 - 15%. When it comes to correlation with the color of the objects, we find that the red objects are all small (mean diameter 65 km), while the gray ones are either small or large (mean diameter 120 km). Also, the gray objects seem to be darker, with a mean value of 5.6%, while for the red objects the albedo can vary from 5 to 15%, with a mean value of 8.5%. All of this shows that there are other physical properties (size and albedo distribution) that make differences between the gray and red objects, even if we do not yet have a physical explanation for the origin of this bimodality.

  5. Measurement of polarization angular coefficients in Z boson leptonic decays with ATLAS at the LHC

    NASA Astrophysics Data System (ADS)

    Fedin, O.

    2017-09-01

    This paper presents the complete set of polarization angular coefficients A 0-7 describing lepton angular distributions in Z boson decay, which were measured at the ATLAS experiment in proton-proton collisions with the energy √ s = 8 TeV. Theoretical values for the difference A 0 - A 2 calculated in the fixed-order QCD perturbation theory O(α s 2 ), demonstrate significant deviation from the measured data, which indicates the necessity of taking into account higher order corrections. The evidence of nonzero coefficients A 5,6,7 was obtained for the first time, in accordance with theoretical calculations in O(α s 2 ) approximation. Measurement of the polarization angular coefficients A i is important for subsequent precision measurement of parameters of the electroweak model at the LHC, such as the sine of Weinberg electroweak mixing angle sin2 θ W and the W boson mass.

  6. Application of the Open Software Foundation (OSF)distributed computing environment to global PACS

    NASA Astrophysics Data System (ADS)

    Martinez, Ralph; Alsafadi, Yasser H.; Kim, Jinman

    1994-05-01

    In this paper, we present our approach to developing Global Picture Archiving and Communication System (GPACS) applications using the Open Software Foundation (OSF) Distributed Computing Environment (DCE) services and toolkits. The OSF DCE services include remote procedure calls, naming service, threads service, time service, file management services, and security service. Several OSF DCE toolkits are currently available from computer and software vendors. Designing distributed Global PACS applications using the OSF DCE approach will feature an open architecture, heterogeneity, and technology independence for GPACS remote consultation and diagnosis applications, including synchronized image annotation, and system privacy and security. The applications can communicate through various transport services and communications networks in a Global PACS environment. The use of OSF DCE services for Global PACS will enable us to develop a robust distributed structure and new user services which feature reliability and scalability for Global PACS environments.

  7. 76 FR 41826 - State, Local, Tribal, and Private Sector Policy Advisory Committee (SLTPS-PAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... From the Federal Register Online via the Government Publishing Office NATIONAL ARCHIVES AND RECORDS ADMINISTRATION Information Security Oversight Office State, Local, Tribal, and Private Sector Policy Advisory Committee (SLTPS-PAC) AGENCY: National Archives and Records Administration....

  8. OSF-distributed computing environment for multimedia telemedicine services in global PACS

    NASA Astrophysics Data System (ADS)

    Martinez, Ralph; Alsafadi, Yasser H.; Kim, Jinman

    1995-05-01

    In this paper, we present our approach to developing global picture archiving and communication system (PACS) remote consultation and diagnosis (RCD) application using the Open Software Foundation (OSF) Distributed Computing Environment (DCE) services and toolkits. The current RCD system now uses programming services similar to those offered by OSF DCE, the Cell Directory Service, the Distributed Time Service, the Security Service, the RPC Facility, and the Threads Facility. In this research we have formally applied OSF DCE services to the Global PACS RCD software. The use of OSF DCE services for Global PACS enables us to develop a robust distributed structure and new user services which feature reliability and scalability for Global PACS environments.

  9. HIPAA-compliant automatic monitoring system for RIS-integrated PACS operation

    NASA Astrophysics Data System (ADS)

    Jin, Jin; Zhang, Jianguo; Chen, Xiaomeng; Sun, Jianyong; Yang, Yuanyuan; Liang, Chenwen; Feng, Jie; Sheng, Liwei; Huang, H. K.

    2006-03-01

    As a governmental regulation, Health Insurance Portability and Accountability Act (HIPAA) was issued to protect the privacy of health information that identifies individuals who are living or deceased. HIPAA requires security services supporting implementation features: Access control; Audit controls; Authorization control; Data authentication; and Entity authentication. These controls, which proposed in HIPAA Security Standards, are Audit trails here. Audit trails can be used for surveillance purposes, to detect when interesting events might be happening that warrant further investigation. Or they can be used forensically, after the detection of a security breach, to determine what went wrong and who or what was at fault. In order to provide security control services and to achieve the high and continuous availability, we design the HIPAA-Compliant Automatic Monitoring System for RIS-Integrated PACS operation. The system consists of two parts: monitoring agents running in each PACS component computer and a Monitor Server running in a remote computer. Monitoring agents are deployed on all computer nodes in RIS-Integrated PACS system to collect the Audit trail messages defined by the Supplement 95 of the DICOM standard: Audit Trail Messages. Then the Monitor Server gathers all audit messages and processes them to provide security information in three levels: system resources, PACS/RIS applications, and users/patients data accessing. Now the RIS-Integrated PACS managers can monitor and control the entire RIS-Integrated PACS operation through web service provided by the Monitor Server. This paper presents the design of a HIPAA-compliant automatic monitoring system for RIS-Integrated PACS Operation, and gives the preliminary results performed by this monitoring system on a clinical RIS-integrated PACS.

  10. Efficiency and effectiveness of an innovative RIS function for patient information reconciliation directly integrated with PACS.

    PubMed

    Nitrosi, Andrea; Bertolini, Marco; Notari, Pietro; Botti, Andrea; Ginocchi, Vladimiro; Tondelli, Giulio; Iori, Mauro; Pattacini, Pierpaolo

    2013-06-01

    In RIS-PACS systems, potential errors occurring during the execution of a radiologic examination can amplify the clinical risks of the patient during subsequent treatments, e.g., of oncologic patients or of those who must do additional treatments based on the initial diagnosis. In Reggio Emilia Province Diagnostic Imaging Department (REDID) we experienced different strategies to reduce clinical risks due to patient reconciliation errors. In 2010, we developed a procedure directly integrated in our RIS-PACS that uses Health Level 7 (HL7) standard messaging, which generates an overlay with the text "under investigation" on the images of the study to be corrected. All the healthcare staff is informed of the meaning of that overlay, and only the radiologist and the emergency services staff can consult these images on PACS. The elimination of image overlay and of any access limitation to PACS was triggered to confirm of the right correction made by RIS-PACS system administrator (SA). The RIS-PACS integrated tool described in this paper allows technologists and radiologists to efficiently highlight patient exam errors and to inform all the users to minimize the overall clinical risks, with a significant savings in costs. Over the years, we have observed a steady decrease in the percentage of reconciled studies. Error reconciliation requires an effective and efficient mechanism. The RIS-PACS integrated tool described in this paper enables technologists and radiologists to quickly and efficiently highlight patient exam errors and inform all the users. Next generation of RIS-PACS could be equipped with similar reconciliation tools.

  11. Design and Implementation of A DICOM PACS With Secure Access Via Internet

    DTIC Science & Technology

    2007-11-02

    system, integrating them with the medical history data. Restricted access based on privileges were design to to make reports or only to consult data...like medium, a concept of exchange of information based on images and data between doctors, services and hospitals. It is a concept of integration...alfonso/pacs.html [2] SL. Lou, Hoogstrate, HK Huang. “Automated PACS image adquisition and recovery scheme for image integrity based on the DICOM

  12. P.A.C. Planner's Workbook. E.S.E.A. Title I. Revised.

    ERIC Educational Resources Information Center

    Davis, Chuck

    This workbook provides information and guidelines for planning and operating Parent Advisory Councils (P.A.C.s) provided for under the Elementary and Secondary Education Act Title I. The first part of the workbook, which was prepared for P.A.C. planners in the Phoenix, Arizona, Union High School District, is a month-by-month guide to P.A.C.…

  13. Problems facing the radiologist tendering for a hospital wide PACS system.

    PubMed

    Pilling, J

    1999-11-01

    As PACS becomes a reality the practical difficulties of installing the new technology become evident. The practical issues of developing a strategy, understanding the market, writing a business case, and an outline based specification are considered. The complexities of European procurement, the evaluation of responses, the contracting process and the problems of implementation, training, assessing the benefits and foreseeing the problems are covered. Provided there is careful attention to detail a hospital can expect to implement a successful PACS system.

  14. Clinical evaluation of using semantic searching engine for radiological imaging services in RIS-integrated PACS

    NASA Astrophysics Data System (ADS)

    Ling, Tonghui; Zhang, Kai; Yang, Yuanyuan; Hua, Yanqing; Zhang, Jianguo

    2015-03-01

    We had designed a semantic searching engine (SSE) for radiological imaging to search both reports and images in RIS-integrated PACS environment. In this presentation, we present evaluation results of this SSE about how it impacting the radiologists' behaviors in reporting for different kinds of examinations, and how it improving the performance of retrieval and usage of historical images in RIS-integrated PACS.

  15. Issues surrounding PACS archiving to external, third-party DICOM archives.

    PubMed

    Langer, Steve

    2009-03-01

    In larger health care imaging institutions, it is becoming increasingly obvious that separate image archives for every department are not cost effective or scalable. The solution is to have each department's picture archiving communication system (PACS) have only a local cache, and archive to an enterprise archive that drives a universal clinical viewer. It sounds simple, but how many PACS can truly work with a third-party Integration of the Health Care Enterprise Compliant Image Archive? The answer is somewhat disappointing.

  16. Perturbed angular distribution of 237Np gamma rays from the 237U parent

    NASA Astrophysics Data System (ADS)

    Ansaldo, Eduardo J.

    1980-09-01

    The anisotropy was measured for the 208.0-59.54 keV gamma cascade in 237Np, corresponding to a positive sign for the M1-E2 mixing ratio of the 208.0 keV transition. The sources were prepared by means of the 238U(e, n) reaction. A discussion on the implications of the present results for the study of hyperfine interactions in neptunium compounds and alloys is included.

  17. Analysis of the perturbed Chandler wobble of the Earth pole

    NASA Astrophysics Data System (ADS)

    Markov, Yu. G.; Perepelkin, V. V.; Filippova, A. S.

    2017-06-01

    Based on the model of a viscoelastic rigid body for the deformable Earth, we investigate the behavior of the main component of the perturbed Earth pole oscillation process, the Chandler wobble. An amplitude- frequency analysis of the perturbed Chandler wobble of the Earth pole due to the precessional motion of the lunar orbit is provided. The parameters of the complex dynamical process that describes the mutual orientation of the Earth's instantaneous rotation axis, the axis of its figure, and its angular momentum vector are studied qualitatively. Using a numerical-analytical approach, we consider the possibilities for identifying the Chandler wobble parameters and fitting the developed refined theoretical model to the real trajectory measurements of the Earth pole.

  18. Elementary derivation of the perturbation equations of celestial mechanics

    NASA Technical Reports Server (NTRS)

    Burns, J. A.

    1976-01-01

    The equations of celestial mechanics that govern the temporal rates of change of orbital elements are completely derived using elementary dynamics and proceeding only from Newton's equation and its solution. Two orbital equations and the four most meaningful orbital elements - semimajor axis, eccentricity, inclination, and longitude of pericenter - are written in terms of the orbital energy (E) and angular momentum (H) per unit mass. The six resulting equations are differentiated with respect to time to see the effect on the orbital elements of small changes in E and H. The usual perturbation equations in terms of disturbing-force components are then derived by computing the manner in which perturbing forces change E and H. The results are applied in a qualitative discussion of the orbital evolution of particles in nonspherical gravitational fields, through atmospheres, and under the action of tides.

  19. Stellar angular diameters from occultation observations.

    NASA Astrophysics Data System (ADS)

    Qian, B.-C.

    This paper reviews the history of measuring stellar angular diameters from lunar occultation observations and the techniques of data analysis. Several effects which can affect the results of measurement are discussed. The author finds that there may be systematic errors in angular diameters measured by various observatories for Aldebaran.

  20. The Orbital Angular Momentum Sum Rule

    NASA Astrophysics Data System (ADS)

    Aslan, Fatma; Burkardt, Matthias

    2015-10-01

    As an alternative to the Ji sum rule for the quark angular momentum, a sum rule for the quark orbital angular momentum, based on a twist-3 generalized parton distribution, has been suggested. We study the validity of this sum rule in the context of scalar Yukawa interactions as well as in QED for an electron.

  1. Orbital angular momentum: a personal memoir.

    PubMed

    Allen, L

    2017-02-28

    A definitive statement of the model used to describe orbital angular momentum is essentially now available. Its early history, and the interaction of those who played key roles in its development over 20 years ago in its development, is outlined in this Memoir.This article is part of the themed issue 'Optical orbital angular momentum'.

  2. Angular Momentum Eigenstates for Equivalent Electrons.

    ERIC Educational Resources Information Center

    Tuttle, E. R.; Calvert, J. B.

    1981-01-01

    Simple and efficient methods for adding angular momenta and for finding angular momentum eigenstates for systems of equivalent electrons are developed. Several different common representations are used in specific examples. The material is suitable for a graduate course in quantum mechanics. (SK)

  3. Orbital angular momentum: a personal memoir

    NASA Astrophysics Data System (ADS)

    Allen, L.

    2017-02-01

    A definitive statement of the model used to describe orbital angular momentum is essentially now available. Its early history, and the interaction of those who played key roles in its development over 20 years ago in its development, is outlined in this Memoir. This article is part of the themed issue 'Optical orbital angular momentum'.

  4. Angular momentum decomposition of Richardson's pairs

    SciTech Connect

    Dussel, G. G.; Sofia, H. M.

    2008-07-15

    The angular momentum decomposition of pairs obtained using Richardson's exact solution of the pairing Hamiltonian for the deformed {sup 174}Yb nucleus are displayed. The probabilities for low angular momenta of the collective pairs are strikingly different from the ones obtained in the BCS ground state.

  5. Lunar occultation stellar angular diameter measurements. II

    NASA Astrophysics Data System (ADS)

    Beavers, W. I.; Eitter, J. J.; Cadmus, R. R., Jr.

    1981-09-01

    The results of analyses from 14 of the 200 lunar occultation events observed at the Fick Observatory between November 1972 and January 1975 are reported. These include two measurements with large angular diameters, seven with small or barely resolvable diameters, two point sources, and three cases in which the records are too noisy to allow angular diameter measurements.

  6. Angular Momentum Eigenstates for Equivalent Electrons.

    ERIC Educational Resources Information Center

    Tuttle, E. R.; Calvert, J. B.

    1981-01-01

    Simple and efficient methods for adding angular momenta and for finding angular momentum eigenstates for systems of equivalent electrons are developed. Several different common representations are used in specific examples. The material is suitable for a graduate course in quantum mechanics. (SK)

  7. Orbital angular momentum in the nucleon

    SciTech Connect

    Garvey, Gerald T.

    2010-05-15

    Analysis of the measured value of the integrated d-bar-u-bar asymmetry (I{sub fas} = 0.147 +- 0.027) in the nucleon show it to arise from nucleon fluctuations into baryon plus pion. Requiring angular momentum conservation in these fluctuations shows the associated orbital angular momentum is equal to the value of the flavor asymmetry.

  8. PAC++: Object-oriented platform for accelerator codes

    SciTech Connect

    Malitsky, N.; Reshetov, A.; Bourianoff, G.

    1994-06-01

    Software packages in accelerator physics have relatively long life cycles. They had been developed and used for a wide range of accelerators in the past as well as for the current projects. For example, the basic algorithms written in the first accelerator Program TRANSPORT are actual for design of most magnet systems. Most of these packages had been implemented on Fortran. But this language is rather inconvenient as a basic language for large integrated projects that possibly could include real-time data acquisition, data base access, graphic riser interface modules (GUI), arid other features. Some later accelerator programs had been based on object-oriented tools (primarily, C++ language). These range from systems for advanced theoretical studies to control system software. For the new generations of accelerators it would be desirable to have an integrated platform in which all simulation and control tasks will be considered with one point of view. In this report the basic principles of an object-oriented platform for accelerator research software (PAC++) are suggested and analyzed. Primary objectives of this work are to enable efficient self-explaining realization of the accelerator concepts and to provide an integrated environment for the updating and the developing of the code.

  9. ROTO PEEN Scalar and VAC-PAC{reg_sign} system

    SciTech Connect

    1998-02-01

    The Pentek, Inc., milling technology, comprising the ROTO PEEN Scaler and the VAC-PAC{reg_sign} waste collection system, is a fully developed and commercialized technology used to remove hazardous coatings from concrete and steel floors, walls, ceilings, and structural components. This report describes a demonstration of the Pentek, Inc., milling system to remove the paint coating from 650 ft{sup 2} of concrete flooring on the service floor of the Chicago Pile-5 (CP-5) Research Reactor. CP-5 is a heavy-water moderated and cooled, highly enriched, uranium-fueled thermal reactor designed to supply neutrons for research. The reactor had a thermal-power rating of 5 megawatts and was operated continuously for 25 years until its final shutdown in 1979. These 25 years of operation produced activation and contamination characteristics representative of other nuclear facilities within the Department of Energy (DOE) complex and the commercial nuclear sector. CP-5 contains many of the essential features of other DOE and commercial nuclear facilities and can be used safely as a demonstration facility for the evaluation of innovative technologies for the future D and D of much larger, more highly contaminated facilities.

  10. Reliable medical imaging transmission for PACS over ATM networks

    NASA Astrophysics Data System (ADS)

    Wei, Wang; Subramanian, K. R.; Zhang, Liren

    2000-05-01

    In an ATM (Asynchronous Transfer Mode)-based PAC system, cell losses during the transmission might cause degradation on the quality of medical images. This in turn will affect the accuracy of the diagnosis. A three-step scheme to minimize the effect of cell losses on the quality of medical images is proposed in this paper. The first step is related to the medical imaging coding before it enters the network, in which, ROIs (Regions of Interest) of the medical imaging which are crucial to diagnosis are kept non-compressed and packetized with pixel-level inter-leaving. Non-compression can make the data of ROIs to be more robust to cell losses than any compression algorithms, while pixel-level inter-leaving is strong for bursty cell losses recovery combined with FEC (Forward Error Correction) at the receiver. The background part of the medical imaging will be compressed using fractal algorithm, which can get very high compression ratio to balance the large amount data of the ROIs. In the second step, the ROIs will be allocated the highest priority during transmission. While in the third step, FEC will be used to minimize the existed cell losses at the receiver. The balance and optimal of these three stages are discussed from the system-level point of view.

  11. Ongoing evaluation of PACS in a clinical setting

    NASA Astrophysics Data System (ADS)

    Trefler, Martin; Russell, Edward

    1992-05-01

    The radiology department of Jackson Memorial Hospital processes 255,000 clinical examinations each year -- 65,000 of which are portable x rays. Film transportation and loss are major obstacles to the smooth operation of this department. To assist in the solution of these problems we have designed and begun the piecemeal installation of a clinical PACS. This system is based on a platform of IBM RISC/6000 computers and software developed by Genesys Corporation. The initial installation involved the digitization of the portable x rays from three ICUs. The images (in the form of a matrix of 2048 X 1648 pixels) are then entered into the network and can be viewed simultaneously in the radiology department and in the ICU. The second phase of installation, involving the images from two CT scanners and two MRI scanners is currently underway. We have evaluated the system from several standpoints. The first is user acceptance. The users are the radiologists who must make the diagnosis at the workstation and the referring physicians who need the diagnosis quickly but also require the image. The radiologists must be comfortable with their diagnosis based on the images presented at the two viewer workstation. This is compared to the use of a multiviewer which presents many radiographs simultaneously. The second parameter for evaluation involves the impact on patient care in terms of the time elapsed between the taking of the radiograph and the presentation to the physician of the image and the diagnosis.

  12. The HST Frontier Fields: DrizzlePac Workflow

    NASA Astrophysics Data System (ADS)

    Avila, Roberto J.; Hammer, D.; Mack, J.; Fruchter, A. S.; Koekemoer, A. M.; Anderson, J.; Barker, E. A.; Hilbert, B.; Gonzaga, S.; Grogin, N. A.; Lotz, J.; Lucas, R. A.; Mountain, M.; Ogaz, S.; Sokol, J.

    2014-01-01

    We demonstrate the power and usability of the DrizzlePac image processing tools developed at the Space Telescope Science Institute. These tools are available to the astronomical community, to align, distortion-correct, and combine stacks of images such as the Frontier Fields mosaics. Using 'cosmic-ray cleaned' images, we test various techniques for producing source catalogs to refine the image alignment. We present methodology for aligning images across visits, across filters, across detectors, and finally to an absolute reference catalog. The alignment solutions, or 'headerlet' files, will be made available to community as 'High Level Science Products' which may be applied to archival data in order to reduce the amount of work needed to re-process the Frontier Fields dataset. We also describe methodology for optimizing the drizzling 'pixfrac' (or drop size) of the final image for any given plate scale in order to provide the best signal-to-noise trade-off between pixel sampling and background noise.

  13. A hospital-wide distributed PACS based on intranet.

    PubMed

    Bandon, D; Ligier, Y; Trayser, G; Girard, C; Logean, M; Ratib, O

    1998-01-01

    A hospital-wide Picture Archiving and Communication System (PACS) is currently under development at the University Hospital of Geneva. After a first implementation including two oneterabyte optical libraries, the system is expanded to integrate all the imaging modalities of the hospital. The new storage requirement is 10 terabytes to cover three year archive. A large distributed image archive has been designed including new archive servers for long-term storage and display servers for medium-term storage. The acquisition, archive and distribution cycles are performed using separated networks combining Fast Ethernet and Ethernet. Image files are distributed to the wide-hospital using a prefetching strategy or an Intranet server, RADIOLAB. The first mode takes advantage of the fully integrated hospital information system DIOGENE 2 to allow the automatic retrieval of studies in advance. The second mode provides a convivial study selection from any conventional WWW (World Wide Web) browser. Image files are then transmitted to the user's display station using HTTP (HyperText Transfer Protocol) and handled by OSIRIS software, which acts as a helper or viewer. Such a system is expected to meet the time requirement, which is less than three seconds per image.

  14. Stereotactic multibeam radiation therapy system in a PACS environment

    NASA Astrophysics Data System (ADS)

    Fresne, Francoise; Le Gall, G.; Barillot, Christian; Gibaud, Bernard; Manens, Jean-Pierre; Toumoulin, Christine; Lemoine, Didier; Chenal, C.; Scarabin, Jean-Marie

    1991-05-01

    A Multibeam radiation therapy treatment is a non-invasive technique devoted to treat a lesion within the cerebral medium by focusing photon-beams on the same target from a high number of entrance points. We present here a computer assisted dosimetric planning procedure which includes: (1) an analysis module to define the target volume by using 2D and 3D displays, (2) a planing module to issue a treatment strategy including the dosimetric simulations and (3) a treatment module setting up the parameters to order the robotized treatment system (i.e. chair- framework, radiation unit machine). Another important feature of this system is its connection to the PACS system SIRENE settled in the University hospital of Rennes which makes possible the archiving and the communication of the multimodal images (CT, MRI, Angiography) used by this application. The corporate use of stereotactic methods and the multimodality imagery ensures spatial coherence and makes the target definition and the cognition of the structures environment more accurate. The dosimetric planning suited to the spatial reference (i.e. the stereotactic frame) guarantees an optimal distribution of the dose computed by an original 3D volumetric algorithm. The robotic approach of the treatment stage has consisted to design a computer driven chair-framework cluster to position the target volume at the radiation unit isocenter.

  15. New AS/400-based PACS for MRI and CT

    NASA Astrophysics Data System (ADS)

    Morin, Richard L.; Forbes, Glenn S.; Gehring, Dale G.; Salutz, James R.; Krueger, Fred L.; Persons, Kenneth R.; Gibbons, Patricia S.

    1990-08-01

    Following our initial investigation of the utility and performance of an AS/400 based token ring network for MRI image archival, we have designed and embarked upon a project to install multiple token ring networks at three physically separated facilities connected with fiber optic communication to archive and display CT and MRI image data. The system design will connect six MRI systems, six CT systems, four optical storage systems, three image display systems, three radiology report scanners, and a foreign archival system. Network communication and archival functions will be managed by an IBM AS/400. Preliminary estimates indicate that savings of media, space, and personnel as well as the additional benefit of online reports with image data will enhance the quality and efficiency of clinical practice. Additionally, we are evaluating a medical image display system (MIDS) to be used for on-demand image review, prefetched image review, and a potential replacement for modality-specific physicians consoles. The MIDS workstation is a promising addition to clinical practice both from the standpoint of an efficient means of image review as well as image interpretation. We consider this joint project to be an important step in the process of understanding the impact and subsequent consequences of electronic image transmission, information communication, and archival within a busy clinical setting. Our performance and design criteria focus upon the impact of this system on the clinical practice within radiology and the subsequent ramifications of PACS throughout the institution.

  16. Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux.

    PubMed

    Amaral, Pauline; Partlan, Erin; Li, Mengfei; Lapolli, Flavio; Mefford, O Thompson; Karanfil, Tanju; Ladner, David A

    2016-09-01

    In microfiltration processes for drinking water treatment, one method of removing trace contaminants is to add powdered activated carbon (PAC). Recently, a version of PAC called superfine PAC (S-PAC) has been under development. S-PAC has a smaller particle size and thus faster adsorption kinetics than conventionally sized PAC. Membrane coating performance of various S-PAC samples was evaluated by measuring adsorption of atrazine, a model micropollutant. S-PACs were created in-house from PACs of three different materials: coal, wood, and coconut shell. Milling time was varied to produce S-PACs pulverized with different amounts of energy. These had different particles sizes, but other properties (e.g. oxygen content), also differed. In pure water the coal based S-PACs showed superior atrazine adsorption; all milled carbons had over 90% removal while the PAC had only 45% removal. With addition of calcium and/or NOM, removal rates decreased, but milled carbons still removed more atrazine than PAC. Oxygen content and specific external surface area (both of which increased with longer milling times) were the most significant predictors of atrazine removal. S-PAC coatings resulted in loss of filtration flux compared to an uncoated membrane and smaller particles caused more flux decline than larger particles; however, the data suggest that NOM fouling is still more of a concern than S-PAC fouling. The addition of calcium improved the flux, especially for the longer-milled carbons. Overall the data show that when milling S-PAC with different levels of energy there is a tradeoff: smaller particles adsorb contaminants better, but cause greater flux decline. Fortunately, an acceptable balance may be possible; for example, in these experiments the coal-based S-PAC after 30 min of milling achieved a fairly high atrazine removal (overall 80%) with a fairly low flux reduction (under 30%) even in the presence of NOM. This suggests that relatively short duration (low energy

  17. SORLA-Dependent and -Independent Functions for PACS1 in Control of Amyloidogenic Processes

    PubMed Central

    Burgert, Tilman; Schmidt, Vanessa; Caglayan, Safak; Lin, Fuyu; Füchtbauer, Annette; Füchtbauer, Ernst-Martin; Nykjaer, Anders; Carlo, Anne-Sophie

    2013-01-01

    Sorting-related receptor with A-type repeats (SORLA) is a sorting receptor for the amyloid precursor protein (APP) that prevents breakdown of APP into Aβ peptides, a hallmark of Alzheimer's disease (AD). Several cytosolic adaptors have been shown to interact with the cytoplasmic domain of SORLA, thereby controlling intracellular routing of SORLA/APP complexes in cell lines. However, the relevance of adaptor-mediated sorting of SORLA for amyloidogenic processes in vivo remained unexplored. We focused on the interaction of SORLA with phosphofurin acidic cluster sorting protein 1 (PACS1), an adaptor that shuttles proteins between the trans-Golgi network (TGN) and endosomes. By studying PACS1 knockdown in neuronal cell lines and investigating transgenic mice expressing a PACS1-binding-defective mutant form of SORLA, we found that disruption of SORLA and PACS1 interaction results in the inability of SORLA/APP complexes to sort to the TGN in neurons and in increased APP processing in the brain. Loss of PACS1 also impairs the proper expression of the cation-independent mannose 6-phosphate receptor and its target cathepsin B, a protease that breaks down Aβ. Thus, our data identified the importance of PACS1-dependent protein sorting for amyloidogenic-burden control via both SORLA-dependent and SORLA-independent mechanisms. PMID:24001769

  18. PAC-1 activates procaspase-3 in vitro through relief of zinc-mediated inhibition.

    PubMed

    Peterson, Quinn P; Goode, David R; West, Diana C; Ramsey, Kara N; Lee, Joy J Y; Hergenrother, Paul J

    2009-04-24

    The direct induction of apoptosis has emerged as a powerful anticancer strategy, and small molecules that either inhibit or activate certain proteins in the apoptotic pathway have great potential as novel chemotherapeutic agents. Central to apoptosis is the activation of the zymogen procaspase-3 to caspase-3. Caspase-3 is the key "executioner" caspase, catalyzing the hydrolysis of a multitude of protein substrates within the cell. Interestingly, procaspase-3 levels are often elevated in cancer cells, suggesting a compound that directly stimulates the activation of procaspase-3 to caspase-3 could selectively induce apoptosis in cancer cells. We recently reported the discovery of a compound, PAC-1, which enhances procaspase-3 activity in vitro and induces apoptotic death in cancer cells in culture and in mouse xenograft models. Described herein is the mechanism by which PAC-1 activates procaspase-3 in vitro. We show that zinc inhibits the enzymatic activity of procaspase-3 and that PAC-1 strongly activates procaspase-3 in buffers that contain zinc. PAC-1 and zinc form a tight complex with one another, with a dissociation constant of approximately 42 nM. The combined data indicate that PAC-1 activates procaspase-3 in vitro by sequestering inhibitory zinc ions, thus allowing procaspase-3 to autoactivate itself to caspase-3. The small-molecule-mediated activation of procaspases has great therapeutic potential and thus this discovery of the in vitro mechanism of action of PAC-1 is critical to the development and optimization of other procaspase-activating compounds.

  19. Preparation and adsorption performance of MnO2/PAC composite towards aqueous glyphosate.

    PubMed

    Cui, Hao; Li, Qin; Qian, Yan; Zhang, Qiu; Zhai, Jianping

    2012-09-01

    Glyphosate (N-phosphonomethylglycine (PMG)) is the organophosphate herbicide most widely used in the world, and industrial production of PMG generates large quantities of wastewater. A manganese dioxide-coated powdered activated carbon (MnO2/PAC) composite was synthesized and investigated for the adsorption of PMG from wastewater. The results of scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectrometry (EDAX) revealed that MnO2 was formed on the surface of the carbon during the modification process. Batch adsorption results showed that the optimal pH for glyphosate adsorption on MnO2/PAC was 3.0. In the range 0.01(-1) molL(-1), glyphosate removal by MnO2/PAC decreased with an increase in ionic strength. Among the coexistent anions, only phosphate showed significant inhibition of PMG removal due to competitive complexation. Batch studies revealed that MnO2/PAC could reach a maximum PMG adsorption capacity of 283 mg g(-1). The Langmuir equilibrium model was found to be suitable for describing PMG sorption, and kinetic studies revealed that adsorption followed second-order rate kinetics. It was also proved that the adsorbed PMG could be effectively desorbed from MnO2/PAC in 1.0 molL(-1) NaOH. All of these results implied that the MnO2/PAC composite may be used as an effective adsorbent for recycling PMG from wastewater.

  20. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent.

    PubMed

    Satyawali, Yamini; Balakrishnan, Malini

    2009-10-15

    This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8L reactor was equipped with a submerged 30 microm nylon mesh filter with 0.05 m(2) filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m(-3)d(-1). PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh.

  1. PACS-2 controls endoplasmic reticulum-mitochondria communication and Bid-mediated apoptosis.

    PubMed

    Simmen, Thomas; Aslan, Joseph E; Blagoveshchenskaya, Anastassia D; Thomas, Laurel; Wan, Lei; Xiang, Yang; Feliciangeli, Sylvain F; Hung, Chien-Hui; Crump, Colin M; Thomas, Gary

    2005-02-23

    The endoplasmic reticulum (ER) and mitochondria form contacts that support communication between these two organelles, including synthesis and transfer of lipids, and the exchange of calcium, which regulates ER chaperones, mitochondrial ATP production, and apoptosis. Despite the fundamental roles for ER-mitochondria contacts, little is known about the molecules that regulate them. Here we report the identification of a multifunctional sorting protein, PACS-2, that integrates ER-mitochondria communication, ER homeostasis, and apoptosis. PACS-2 controls the apposition of mitochondria with the ER, as depletion of PACS-2 causes BAP31-dependent mitochondria fragmentation and uncoupling from the ER. PACS-2 also controls formation of ER lipid-synthesizing centers found on mitochondria-associated membranes and ER homeostasis. However, in response to apoptotic inducers, PACS-2 translocates Bid to mitochondria, which initiates a sequence of events including the formation of mitochondrial truncated Bid, the release of cytochrome c, and the activation of caspase-3, thereby causing cell death. Together, our results identify PACS-2 as a novel sorting protein that links the ER-mitochondria axis to ER homeostasis and the control of cell fate, and provide new insights into Bid action.

  2. Orbital angular momentum in optical fibers

    NASA Astrophysics Data System (ADS)

    Bozinovic, Nenad

    Internet data traffic capacity is rapidly reaching limits imposed by nonlinear effects of single mode fibers currently used in optical communications. Having almost exhausted available degrees of freedom to orthogonally multiplex data in optical fibers, researchers are now exploring the possibility of using the spatial dimension of fibers, via multicore and multimode fibers, to address the forthcoming capacity crunch. While multicore fibers require complex manufacturing, conventional multi-mode fibers suffer from mode coupling, caused by random perturbations in fibers and modal (de)multiplexers. Methods that have been developed to address the problem of mode coupling so far, have been dependent on computationally intensive digital signal processing algorithms using adaptive optics feedback or complex multiple-input multiple-output algorithms. Here we study the possibility of using the orbital angular momentum (OAM), or helicity, of light, as a means of increasing capacity of future optical fiber communication links. We first introduce a class of specialty fibers designed to minimize mode coupling and show their potential for OAM mode generation in fibers using numerical analysis. We then experimentally confirm the existence of OAM states in these fibers using methods based on fiber gratings and spatial light modulators. In order to quantify the purity of created OAM states, we developed two methods based on mode-image analysis, showing purity of OAM states to be 90% after 1km in these fibers. Finally, in order to demonstrate data transmission using OAM states, we developed a 4-mode multiplexing and demultiplexing systems based on free-space optics and spatial light modulators. Using simple coherent detection methods, we successfully transmit data at 400Gbit/s using four OAM modes at a single wavelength, over 1.1 km of fiber. Furthermore, we achieve data transmission at 1.6Tbit/s using 10 wavelengths and two OAM modes. Our study indicates that OAM light can exist

  3. Physical angular momentum separation for QED

    NASA Astrophysics Data System (ADS)

    Sun, Weimin

    2017-04-01

    We study the non-uniqueness problem of the gauge-invariant angular momentum separation for the case of QED, which stems from the recent controversy concerning the proper definitions of the orbital angular momentum and spin operator of the individual parts of a gauge field system. For the free quantum electrodynamics without matter, we show that the basic requirement of Euclidean symmetry selects a unique physical angular momentum separation scheme from the multitude of the possible angular momentum separation schemes constructed using the various gauge-invariant extensions (GIEs). Based on these results, we propose a set of natural angular momentum separation schemes for the case of interacting QED by invoking the formalism of asymptotic fields. Some perspectives on such a problem for the case of QCD are briefly discussed.

  4. Angular Resolution Enhanced Spitzer images

    NASA Astrophysics Data System (ADS)

    Velusamy, T.; Beichman, C. A.; Backus, C. R.; Marsh, K. A.; Thompson, T. J.

    2004-05-01

    We have developed a 'HiRes' software for deconvolution of Spitzer images that increases the angular resolution by a factor of two to three over that obtainable in a standard mosaiced image. This software is an extension of the Maximum Correlation Method (MCM) described by Aumann et al. (1990 AJ, 99, 1674), incorporating features that are applicable to the Spitzer data and FFT convolutions to speed up. While the Spitzer Space Telescope provides unprecedented sensitivity in the infrared, its spatial resolution is limited by the relatively small aperture (0.85 m) of the primary mirror. In this paper we present resolution enhanced Spitzer images demonstrating the benefits of HiRes imaging: (1) The ability to detect sources below the diffraction-limited confusion level; at 160 micron, the corresponding increase in confusion-limited sensitivity is about a factor of two. (2) The ability to separate blended sources, and thereby provide guidance to point-source extraction procedures. (3) An improved ability to show the spatial morphology of resolved sources. This work was performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  5. Angular Momentum of Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Butler, Kirsty M.; Obreschkow, Danail; Oh, Se-Heon

    2017-01-01

    We present measurements of baryonic mass {M}{{b}} and specific angular momentum (sAM) {j}{{b}} in 14 rotating dwarf Irregular (dIrr) galaxies from the LITTLE THINGS sample. These measurements, based on 21 cm kinematic data from the Very Large Array and stellar mass maps from the Spitzer Space Telescope, extend previous AM measurements by more than two orders of magnitude in {M}{{b}}. The dwarf galaxies show systematically higher {j}{{b}} values than expected from the {j}{{b}}\\propto {M}{{b}}2/3 scaling of spiral galaxies, representative of a scale-free galaxy formation scenario. This offset can be explained by decreasing baryon mass fractions {f}{{M}}={M}{{b}}/{M}{dyn} (where {M}{dyn} is the dynamical mass) with decreasing {M}{{b}} (for {M}{{b}}< {10}11 {M}ȯ ). We find that the sAM of neutral atomic hydrogen (H i) alone is about 2.5 times higher than that of the stars. The M–j relation of H i is significantly steeper than that of the stars, as a direct consequence of the systematic variation of the H i fraction with {M}{{b}}.

  6. Squeezing of X waves with orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Ornigotti, Marco; Villari, Leone Di Mauro; Szameit, Alexander; Conti, Claudio

    2017-01-01

    Multilevel quantum protocols may potentially supersede standard quantum optical polarization-encoded protocols in terms of amount of information transmission and security. However, for free-space telecommunications, we do not have tools for limiting loss due to diffraction and perturbations, as, for example, turbulence in air. Here we study propagation invariant quantum X waves with angular momentum; this representation expresses the electromagnetic field as a quantum gas of weakly interacting bosons. The resulting spatiotemporal quantized light pulses are not subject to diffraction and dispersion, and are intrinsically resilient to disturbances in propagation. We show that spontaneous down-conversion generates squeezed X waves useful for quantum protocols. Surprisingly, the orbital angular momentum affects the squeezing angle, and we predict the existence of a characteristic axicon aperture for maximal squeezing. These results may boost the applications in free space of quantum optical transmission and multilevel quantum protocols, and may also be relevant for novel kinds of interferometers, such as satellite-based gravitational wave detectors.

  7. The power of perturbation theory

    NASA Astrophysics Data System (ADS)

    Serone, Marco; Spada, Gabriele; Villadoro, Giovanni

    2017-05-01

    We study quantum mechanical systems with a discrete spectrum. We show that the asymptotic series associated to certain paths of steepest-descent (Lefschetz thimbles) are Borel resummable to the full result. Using a geometrical approach based on the PicardLefschetz theory we characterize the conditions under which perturbative expansions lead to exact results. Even when such conditions are not met, we explain how to define a different perturbative expansion that reproduces the full answer without the need of transseries, i.e. non-perturbative effects, such as real (or complex) instantons. Applications to several quantum mechanical systems are presented.

  8. Instabilities in mimetic matter perturbations

    NASA Astrophysics Data System (ADS)

    Firouzjahi, Hassan; Gorji, Mohammad Ali; Mansoori, Seyed Ali Hosseini

    2017-07-01

    We study cosmological perturbations in mimetic matter scenario with a general higher derivative function. We calculate the quadratic action and show that both the kinetic term and the gradient term have the wrong sings. We perform the analysis in both comoving and Newtonian gauges and confirm that the Hamiltonians and the associated instabilities are consistent with each other in both gauges. The existence of instabilities is independent of the specific form of higher derivative function which generates gradients for mimetic field perturbations. It is verified that the ghost instability in mimetic perturbations is not associated with the higher derivative instabilities such as the Ostrogradsky ghost.

  9. Gauge invariant perturbations of self-similar Lemaitre-Tolman-Bondi spacetime: Even parity modes with l{>=}2

    SciTech Connect

    Waters, Thomas J.; Nolan, Brien C.

    2009-04-15

    In this paper we consider gauge invariant linear perturbations of the metric and matter tensors describing the self-similar Lemaitre-Tolman-Bondi (timelike dust) spacetime containing a naked singularity. We decompose the angular part of the perturbation in terms of spherical harmonics and perform a Mellin transform to reduce the perturbation equations to a set of ordinary differential equations with singular points. We fix initial data so the perturbation is finite on the axis and the past null cone of the singularity, and follow the perturbation modes up to the Cauchy horizon. There we argue that certain scalars formed from the modes of the perturbation remain finite, indicating linear stability of the Cauchy horizon.

  10. Causal compensated perturbations in cosmology

    NASA Technical Reports Server (NTRS)

    Veeraraghavan, Shoba; Stebbins, Albert

    1990-01-01

    A theoretical framework is developed to calculate linear perturbations in the gravitational and matter fields which arise causally in response to the presence of stiff matter sources in a FRW cosmology. It is shown that, in order to satisfy energy and momentum conservation, the gravitational fields of the source must be compensated by perturbations in the matter and gravitational fields, and the role of such compensation in containing the initial inhomogeneities in their subsequent evolution is discussed. A complete formal solution is derived in terms of Green functions for the perturbations produced by an arbitrary source in a flat universe containing cold dark matter. Approximate Green function solutions are derived for the late-time density perturbations and late-time gravitational waves in a universe containing a radiation fluid. A cosmological energy-momentum pseudotensor is defined to clarify the nature of energy and momentum conservation in the expanding universe.

  11. Inflationary perturbations in bimetric gravity

    SciTech Connect

    Cusin, Giulia; Durrer, Ruth; Guarato, Pietro; Motta, Mariele E-mail: ruth.durrer@unige.ch E-mail: mariele.motta@unige.ch

    2015-09-01

    In this paper we study the generation of primordial perturbations in a cosmological setting of bigravity during inflation. We consider a model of bigravity which can reproduce the ΛCDM background and large scale structure and a simple model of inflation with a single scalar field and a quadratic potential. Reheating is implemented with a toy-model in which the energy density of the inflaton is entirely dissipated into radiation. We present analytic and numerical results for the evolution of primordial perturbations in this cosmological setting. We find that the amplitude of tensor perturbations generated during inflation is sufficiently suppressed to avoid the effects of the tensor instability discovered in refs. [1,2] which develops during the cosmological evolution in the physical sector. We argue that from a pure analysis of the tensor perturbations this bigravity model is compatible with present observations. However, we derive rather stringent limits on inflation from the vector and scalar sectors.

  12. Perturbative gadgets at arbitrary orders

    NASA Astrophysics Data System (ADS)

    Jordan, Stephen P.; Farhi, Edward

    2008-06-01

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets have become a standard tool in the theory of quantum computation. Here we construct generalized gadgets so that one can directly obtain arbitrary k -body effective interactions from two-body Hamiltonians. These effective interactions arise from the k th order in perturbation theory.

  13. Causal compensated perturbations in cosmology

    NASA Technical Reports Server (NTRS)

    Veeraraghavan, Shoba; Stebbins, Albert

    1990-01-01

    A theoretical framework is developed to calculate linear perturbations in the gravitational and matter fields which arise causally in response to the presence of stiff matter sources in a FRW cosmology. It is shown that, in order to satisfy energy and momentum conservation, the gravitational fields of the source must be compensated by perturbations in the matter and gravitational fields, and the role of such compensation in containing the initial inhomogeneities in their subsequent evolution is discussed. A complete formal solution is derived in terms of Green functions for the perturbations produced by an arbitrary source in a flat universe containing cold dark matter. Approximate Green function solutions are derived for the late-time density perturbations and late-time gravitational waves in a universe containing a radiation fluid. A cosmological energy-momentum pseudotensor is defined to clarify the nature of energy and momentum conservation in the expanding universe.

  14. Refining the pH response in A spergillus nidulans: a modulatory triad involving PacX, a novel zinc binuclear cluster protein

    PubMed Central

    Bussink, Henk‐Jan; Bignell, Elaine M.; Múnera‐Huertas, Tatiana; Lucena‐Agell, Daniel; Scazzocchio, Claudio; Espeso, Eduardo A.; Bertuzzi, Margherita; Rudnicka, Joanna; Negrete‐Urtasun, Susana; Peñas‐Parilla, Maria M.; Rainbow, Lynne; Peñalva, Miguel Á.; Arst, Herbert N.

    2015-01-01

    Summary The A spergillus nidulans PacC transcription factor mediates gene regulation in response to alkaline ambient pH which, signalled by the Pal pathway, results in the processing of PacC72 to PacC27 via PacC53. Here we investigate two levels at which the pH regulatory system is transcriptionally moderated by pH and identify and characterise a new component of the pH regulatory machinery, PacX. Transcript level analysis and overexpression studies demonstrate that repression of acid‐expressed pal F, specifying the Pal pathway arrestin, probably by PacC27 and/or PacC53, prevents an escalating alkaline pH response. Transcript analyses using a reporter and constitutively expressed pac C  trans‐alleles show that pac C preferential alkaline‐expression results from derepression by depletion of the acid‐prevalent PacC72 form. We additionally show that pac C repression requires PacX. pac X mutations suppress PacC processing recalcitrant mutations, in part, through derepressed PacC levels resulting in traces of PacC27 formed by pH‐independent proteolysis. pac X was cloned by impala transposon mutagenesis. PacX, with homologues within the Leotiomyceta, has an unusual structure with an amino‐terminal coiled‐coil and a carboxy‐terminal zinc binuclear cluster. pacX mutations indicate the importance of these regions. One mutation, an unprecedented finding in A . nidulans genetics, resulted from an insertion of an endogenous Fot1‐like transposon. PMID:26303777

  15. Robust stability under additive perturbations

    NASA Technical Reports Server (NTRS)

    Bhaya, A.; Desoer, C. A.

    1985-01-01

    A MIMO linear time-invariant feedback system 1S(P,C) is considered which is assumed to be U-stable. The plant P is subjected to an additive perturbation Delta P which is proper but not necessarily stable. It is proved that the perturbed system is U-stable if and only if Delta P(I + Q x Delta P) exp -1 is U-stable.

  16. Lectures on perturbative string theories

    SciTech Connect

    Ooguri, Hirosi; Yin, Z. |

    1997-02-01

    These lecture notes on String Theory constitute an introductory course designed to acquaint the students with some basic factors of perturbative string theories. They are intended as preparation for the more advanced courses on non-perturbative aspects of string theories in the school. The course consists of five lectures: (1) Bosonic String, (2) Toroidal Compactifications, (3) Superstrings, (4) Heterotic Strings, and (5) Orbifold Compactifications.

  17. Wave Angular Momentum in Nonneutral Plasmas

    NASA Astrophysics Data System (ADS)

    Gould, Roy W.

    1999-11-01

    We show that angular momentum and energy are added or removed when exciting a mode, such as a diocotron, Trivelpiece-Gould, or Dubin mode, and we calculate the rates (with sign) at which angular momentum and energy are added by the application of a ``rotating wall" field. Excitation of a mode which rotates faster than the plasma increases the total angular momentum and total energy and compresses the plasma, whereas excitation of a mode which rotates slower than the plasma decreases the total angular momentum and total energy and expands the plasma, in accord with recent ``rotating wall" experiments^1. Furthermore, the transfer rates are sharply peaked when the angular velocity of the ``rotating wall" is equal to the angular velocity of a mode, because mode excitation is a resonant process. Thus mode excitation is a very efficient way to transfer angular momentum and energy to or from the plasma. We also calculate the torque on a spheroidal Coulomb crystal which is phase-locked^2 to a ``rotating wall" field, and discuss phase oscillations and the maximum rate of acceleration which can be achieved. 1 F. Anderegg et al, Phys. Rev. Lett. 81 4875 (1998). 2 X.-P. Huang et al, Phys. Rev. Lett. 80 73 (1998).

  18. Photoelectron angular distributions from two-photon ionizations of atoms

    NASA Astrophysics Data System (ADS)

    Haber, Louis Hamilton

    Photoelectron angular distributions provide detailed information about interferences between different quantum pathways of photoionization. Measurements of photoelectron energies and angular distributions from two-color two-photon ionizations of atoms using ultrashort pulses of extreme ultraviolet and optical light are performed using a novel, homebuilt experimental instrument. The setup is composed of an amplified femtosecond laser system, a high-order harmonic generation source, and an interaction region with photoelectron velocity map imaging The experimental temporal resolution is determined to be approximately 100 fs. Two different types of two-photon ionizations are investigated. Photoelectron angular distributions from resonant two-photon ionizations of helium are measured using the 15th high-order harmonic to excite from the ground state to either the 1s3p 1P1 state at 23.1 eV or to the 1s4p 1 P1 state at 23.7 eV and either 800, 400, or 267 nm to ionize. The anisotropy parameters allow for the determination of the energy-dependent ratios of radial dipole matrix elements and the phase shift differences between the S and D partial waves. Using available total cross section measurements, the absolute partial cross sections of the 1s3p1P 1 state are obtained, providing the complete information on photoionization. The experimental results are in excellent agreement with theoretical predictions using the one-electron model. Additional experiments are aimed at studying atomic free-free transitions. Two-color two-photon above threshold ionizations of helium and argon are investigated using selected high-order harmonics and perturbative infrared dressing fields. The measured anisotropy parameters and cross section ratios of the positive and negative above threshold ionization sidebands are compared to theoretical predictions using second-order perturbation theory and the soft-photon approximation. In general, deviations between the experimental results and the

  19. Improving the performance of an aerobic membrane bioreactor (MBR) treating pharmaceutical wastewater with powdered activated carbon (PAC) addition.

    PubMed

    Kaya, Yasemin; Bacaksiz, A Murat; Golebatmaz, Ugur; Vergili, Ilda; Gönder, Z Beril; Yilmaz, Gulsum

    2016-04-01

    In this study, the effects of organic loading rate (OLR) and the addition of powdered activated carbon (PAC) on the performance and membrane fouling of MBR were conducted to treat real pharmaceutical process wastewater. Over 145 days of operation, the MBR system was operated at OLRs ranging from 1 to 2 kg COD m(-3) day(-1) without sludge wasting. The addition of PAC provided an improvement in the flux, despite an increase in the OLR:PAC ratio. The results demonstrated that the hybrid PAC-MBR system maintained a reduced amount of membrane fouling and steadily increased the removal performance of etodolac. PAC addition reduced the deposition of extracellular polymeric substance and organic matter on the membrane surface and resulted an increase in COD removal even at higher OLRs with low PAC addition. Membrane fouling mechanisms were investigated using combined adsorption fouling models. Modified fouling index values and normalized mass transfer coefficient values indicated that predominant fouling mechanism was cake adsorption.

  20. PACS reading time comparision: the workstation versus alternator for ultrasound

    NASA Astrophysics Data System (ADS)

    Horii, Steven C.; Garra, Brian S.; Mun, Seong K.; Singer, Jon; Zeman, Robert K.; Levine, Betty A.; Fielding, Robert; Lo, Shih-Chung B.

    1991-07-01

    During a nine-month period, ultrasound reading was switched between a PACS workstation (CommViewR, AT&T/Philips) and a film alternator (PanoramascopeR RADX). The two radiologists who participated in this study were well acquainted with the operation of both systems. A total of 430 cases were read, and whether on film (n equals 292) or from the workstation (n equals 138), a routine mix of cases was interpreted. A timing study was performed which involved recording the time it took to read and dictate the cases. A previous study had concentrated on other facets of the total time, so these were not repeated. Over all cases read, the workstation readings took longer by an average of approximately 33 seconds per case. A review of the reports generated showed no differences in the average length, so that the time difference was thought to be due to other factors. The majority of the difference is the result of the longer time it takes to display all images at full resolution on the workstation. On the alternator, the average number of films per case can fit on one alternator panel, so to see all images, there is no need to page to the next panel. The workstation, on the other hand, can only display about half of the total images per study at once, so that paging must be done for almost all cases. This paper presents the detailed findings of this study and discusses the implications for the daily use of a workstation for reading.