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Sample records for pac perturbed angular

  1. PAC (perturbed angular correlation) analysis of defect motion by Blume's stochastic model for I = 5/2 electric quadrupole interactions

    SciTech Connect

    Evenson, W.E. . Dept. of Physics and Astronomy); Gardner, J.A.; Wang, Ruiping . Dept. of Physics); Su, Han-Tzong ); McKale, A.G. )

    1990-01-01

    Using Blume's stochastic model and the approach of Winkler and Gerdau, we have computed-time-dependent effects on perturbed angular correlation (PAC) spectra due to defect motion in solids in the case of I = (5/2) electric quadrupole interactions. We report detailed analysis for a family of simple models: XYZ + Z'' models, in which the symmetry axis of an axial efg is allowed to fluctuate among orientations along x, y, and z axes, and a static axial efg oriented along the z axis is added to the fluctuating efgs. When the static efg is zero, this model is termed the XYZ'' model. Approximate forms are given for G{sub 2}(t) in the slow and rapid fluctuation regimes, i.e. suitable for the low and high temperature regions, respectively. Where they adequately reflect the underlying physical processes, these expressions allow one to fit PAC data for a wide range of temperatures and dopant concentrations to a single model, thus increasing the uniqueness of the interpretation of the defect properties. Application of the models are given for zirconia and ceria ceramics. 14 refs.

  2. PAC (perturbed angular correlation) perturbation factor for spin 5/2 nuclei subject to a rapidly fluctuation EFC (electric field gradient)

    SciTech Connect

    Evenson, W.E. . Dept. of Physics and Astronomy); McKale, A.G.; Su, H.T.; Gardner, J.A. . Dept. of Physics)

    1990-01-01

    We report numerical computations of the PAC perturbation factor G{sub 2}(t) for spin 5/2 nuclei subject to a static EFG symmetric about the z-axis and an additional axially-symmetric EFG hose symmetry axis fluctuates randomly among the x,y,z directions. For sufficiently large fluctuation rates, the numerical results are described by the expression for the static interaction alone with the addition of relaxation terms. Results of applying this model to {sup 111}Cd TDPAC measurements on tetragonal ZrO{sub 2} are described briefly. The model allows one to evaluate the probability that oxygen vacancies are trapped, the energy of association of vacancy-metal pairs, and the vacancy activation energy of motion. 4 refs., 3 figs.

  3. Fully digital time differential perturbed angular correlation (TDPAC) spectrometer

    NASA Astrophysics Data System (ADS)

    Herden, C.; Röder, J.; Gardner, J. A.; Becker, K. D.

    2008-09-01

    A new generation time differential perturbed angular correlation (PAC) spectrometer has been designed and built. The design strategy and details of the data collection and reduction methodology are reported. First results obtained by the new spectrometer are reported and compared with PAC data obtained by more conventional means.

  4. (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.

  5. Studying oxygen vacancies in ceramics by perturbed angular correlation spectroscopy

    SciTech Connect

    Su, Han-Tzong; Wang, Ruiping; Fuchs, H.; Gardner, J.A. . Dept. of Physics); Evenson, W.E. . Dept. of Physics); Sommers, J.A. )

    1990-01-01

    Perturbed angular correlation measurements in tetragonal and cubic zirconia and in ceria are described. A physically reasonable and self-consistent interpretation of these data implies that oxygen vacancies are trapped at a second neighbor position by Cd in tetragonal zirconia and by In in ceria. For Cd in tetragonal zirconia, the vacancy trap energy is found to be 0.44 eV, and the energy barrier between adjacent trap sites is approximately 0.8 eV. The activation energy of an oxygen vacancy hopping between trap sites around {sup 111}Cd in ceria is found to be 0.55 eV. The activation energy for oxygen vacancy hopping in cubic zirconia, as detected by {sup 181}Ta PAC, is about 1.0 eV and independent of the Y concentration. 12 refs., 4 figs.

  6. Perturbed angular correlation experiments on the pressure-induced structural modification of bovine serum albumin.

    PubMed

    Ceolín, M

    2000-09-11

    The hydrodynamic behaviour of the bovine serum albumin (BSA) was studied by means of the Perturbed Angular Correlation (PAC) technique as a function of the hydrostatic pressure (up to 4.1 kbar) applied to the sample. The results have clearly shown that at moderated pressures (around 1.5 kbar) the BSA molecule suffers structural modifications which produces an increase of the molecular volume and the rotational correlation time of the molecule. About the reversibility of the process, our results indicate that the changes are fully irreversible. Our experiments are the first devoted to the study of the high-pressure behaviour of biological molecules using the PAC technique. PMID:10989128

  7. Perturbed angular correlation study of the ion exchange of indium into silicalite zeolites

    NASA Astrophysics Data System (ADS)

    Ramallo-López, J. M.; Requejo, F. G.; Rentería, M.; Bibiloni, A. G.; Miró, E. E.

    1999-09-01

    Two indium-containing silicalite zeolites (In/H ZSM5) catalysts prepared by wet impregnation and ionic exchange were characterized by the Perturbed Angular Correlation (PAC) technique using 111In as probe to determine the nature of the indium species. Some of these species take part in the catalytic reaction of the selective reduction (SCR) of NOx with methane. PAC experiments were performed at 500ºC in air before and after reduction reoxidation treatments on the catalysts in order to determine the origin of the different hyperfine interactions and then the degree of ionic exchange. Complementary catalytic activity characterizations were also performed. PAC experiments performed on the catalyst obtained by wet impregnation showed that all In-atoms form In2O3 crystallites while almost 70% of In-atoms form In2O3 in the catalyst obtained by ionic exchange. The PAC experiments of both catalysts performed after the reduction reoxidation treatment revealed the presence of two hyperfine interactions, different from those corresponding to indium in In2O3. These hyperfine interactions should be associated to disperse In species responsible of the catalytic activity located in the ionic exchange-sites of the zeolites.

  8. 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.

  9. Drell-Yan lepton angular distributions in perturbative QCD

    NASA Astrophysics Data System (ADS)

    Lambertsen, Martin; Vogelsang, Werner

    2016-06-01

    We present a comprehensive comparison of the available experimental data for the Drell-Yan lepton angular coefficients λ and ν to calculations at leading and next-to-leading order of perturbative QCD. To obtain the next-to-leading order corrections, we make use of publicly available numerical codes that allow us to compute the Drell-Yan cross section at second order in perturbation theory and from which the contributions we need can be extracted. Our comparisons reveal that perturbative QCD is able to describe the experimental data overall rather well, especially at colliders, but also in the fixed-target regime. On the basis of the angular coefficients alone, there appears to be little (if any) convincing evidence for effects that go beyond fixed-order collinear factorized perturbation theory, although the presence of such effects is not ruled out.

  10. Stability of erythrocyte ghosts: a gamma-ray perturbed angular correlation study.

    PubMed Central

    Kruse, C A; Tin, G W; Baldeschwieler, J D

    1983-01-01

    The structural integrity of erythrocyte ghosts made by the preswell and slow-dialysis techniques has been studied in vitro by use of gamma-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 quantitites 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. PMID:6572379

  11. Fitting PAC spectra with stochastic models: PolyPacFit

    NASA Astrophysics Data System (ADS)

    Zacate, M. O.; Evenson, W. E.; Newhouse, R.; Collins, G. S.

    2010-04-01

    PolyPacFit is an advanced fitting program for time-differential perturbed angular correlation (PAC) spectroscopy. It incorporates stochastic models and provides robust options for customization of fits. Notable features of the program include platform independence and support for (1) fits to stochastic models of hyperfine interactions, (2) user-defined constraints among model parameters, (3) fits to multiple spectra simultaneously, and (4) any spin nuclear probe.

  12. A weak magnetism observed in SnO2 doped with Fe by means of Perturbed Gamma-Gamma Angular Correlation and Mössbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramos, J. M.; Carbonari, A. W.; Martucci, T.; Costa, M. S.; Cabrera-Pasca, G. A.; Macedo, M. A. V.; Saxena, R. N.

    Nano-structured samples of SnO2 doped with Fe prepared by the sol-gel method were studied by the Perturbed Gamma-Gamma Angular Correlation (PAC) Spectroscopy using 111In (111Cd) probe nuclei as well as by 57Fe Mšssbauer spectroscopy. The samples were prepared from very pure metallic Sn and Fe. Carrier-free 111In nuclei were introduced during the sol-gel process of sample preparation for PAC measurements. The PAC measurements were carried out after annealing the samples at different temperatures and the results show a combined electric quadrupole and magnetic dipole interaction for probe nuclei that do not occupy the regular Sn sites. The hyperfine parameters revealed weak magnetic interactions.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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 Λ-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.

  15. 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.

  16. A Perturbed-Angular-Correlation Study of Hyperfine Interactions at 181Ta in α-Fe2O3

    NASA Astrophysics Data System (ADS)

    Pasquevich, A. F.; Junqueira, A. C.; Carbonari, A. W.; Saxena, R. N.

    2004-11-01

    The hyperfine interactions at 181Ta ions on Fe3+ sites in α-Fe2O3 (hematite) were studied in the temperature range 11 1100 K by means of the perturbed angular correlation (PAC) technique. The 181Hf(β-)181Ta probe nuclei were introduced chemically into the sample during the preparation. The hyperfine interaction measurements allow to observe the magnetic phase transition and to characterize the supertransferred hyperfine magnetic field Bhf and the electric field gradient (EFG) at the impurity sites. The angles between Bhf and the principal axes of the EFG were determined. The Morin transition was also observed. The results are compared with those of similar experiments carried out using 111Cd probe.

  17. 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.

  18. Interpretation of perturbed angular distribution results for19F implanted into diamond

    NASA Astrophysics Data System (ADS)

    Connell, S.; Sellschop, J. P. F.; Stemmet, M. C.; Appel, H.; Bharuth-Ram, K.; Verwoerd, W. S.

    1990-08-01

    Perturbed Angular Distribution measurements have been made on natural diamond using recoil implanted fluorine ions as probes. Two distinct lattice sites for fluorine in diamond were found. Site identifications prompted by theoretical cluster calculations are presented. The PAD data are well described by a texture theory, though the origin of the texture effects is presently not known.

  19. 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.

  20. Temperature dependence of electric field gradient in LaCoO3 perovskite investigated by perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Junqueira, Astrogildo C.; Carbonari, Artur W.; Saxena, Rajendra N.; Mestnik-Filho, José; Dogra, Rakesh

    2005-11-01

    The time differential perturbed angular correlation (TDPAC) technique was used to study the temperature dependence of electric field gradient (EFG) in LaCoO3 perovskite using {}^{111}\\mathrm {In}\\rightarrow {}^{111}\\mathrm {Cd} and {}^{181}\\mathrm {Hf} \\rightarrow {}^{181}\\mathrm {Ta} nuclear probes. The radioactive parent nuclei 111In and 181Hf were introduced into the oxide lattice through a chemical process during sample preparation and were found to occupy only the Co sites in LaCoO3. The PAC measurements with 111Cd and 181Ta probes were made in the temperature range of 4.2-1146 K and 4.2-1004 K, respectively. No long-range magnetic order was observed up to 4.2 K. The EFGs at 111Cd and 181Ta show very similar temperature dependences. They increase slowly between 4.2 and about 77 K and then decrease almost linearly with increasing temperature until about 500-600 K, where a broad peak-like structure is observed, followed by linear decrease at still higher temperatures. These discontinuities at about 77 K and 500-600 K have been interpreted as thermally activated spin state transitions from the low-spin (t2g6eg0) ground state configuration to the intermediate-spin (t2g5eg1) state and from the intermediate-spin to the high-spin (t2g4eg2) state of the Co3+ ion, confirming previous observation in other recent studies. An indication of a Jahn-Teller distortion, which stabilizes the intermediate-spin state with orbital ordering, is also pointed out.

  1. 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.

  2. 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.

  3. Perturbed angular correlation study of radiation-induced defects in Rh metal

    NASA Astrophysics Data System (ADS)

    Chawda, M.; Patel, N.; Sebastian, K. C.; Somayajulu, D. R. S.; Sarkar, M.; Singh, R. P.; Murlithar, S.; Awasthi, D. K.

    2006-06-01

    Radiation-induced defects are studied in cubic rhodium metal, using the local probe technique 'Time differential perturbed angular correlation (TDPAC) at liquid N-2 temperature. Isochronal annealing was done at 300, 1073 and 1473 K temperatures. The irradiated sample showed two quadrupole interaction frequencies at 1150 and 93 MHz. The low frequency disappeared at room-temperature annealing, which was assigned to In trapped at a vacancy, whereas the higher frequency remained up to high temperatures and was attributed to In trapped at Rh-C complexes in the Rh matrix.

  4. The suitability of 160Tb as a PAC probe for studies of biomolecules.

    PubMed

    Sidhu, N P; Sahota, H S; Cheema, T S

    1988-01-01

    The gamma-ray perturbed angular correlation (PAC) studies were made with 160Tb as a probe in MES (2[N-morpholino]-ethane sulphonic acid) solutions of various concentrations. The measurements indicate no influence of concentration of the environment on its interaction with Tb3+ ion and as such reveal the fact that 160Tb is not a good probe for PAC studies. PMID:2840419

  5. Magnetic interaction in NdScGe: a local investigation by perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Mishra, S. N.; Dhar, S. K.

    2004-02-01

    The magnetic and electric hyperfine interactions for the 111Cd probe nucleus in the equi-atomic ferromagnetic compound NdScGe (T_{\\mathrm {c}}\\sim 200 K) have been investigated by the time differential perturbed angular correlation (TDPAC) technique. The Cd probe occupying the Sc site experiences a large magnetic hyperfine field with saturation value Bhf(0) = -8.5 T. By comparing the results with the hyperfine field data in Nd metal and estimates made with the RKKY interaction, we find an indication for sizeable spin polarization of the conduction electrons in NdScGe. In addition, we find evidence of lattice softening near the Curie temperature reflected by an abrupt decrease in the quadrupole interaction frequency ngrQ(T).

  6. Hyperfine magnetic field at Ta impurities in nickel: Perturbed angular correlation and first principle calculation study

    NASA Astrophysics Data System (ADS)

    Cekić, B. Dj.; Umićević, A. B.; Belošević-Čavor, J. N.; Koteski, V. J.; Ivanovski, V. N.; Stojković, M. N.

    2008-03-01

    The hyperfine magnetic field (H) in 0.2 at.% Hf-Ni alloy is measured at the 181Ta probe using the time-differential perturbed angular correlation (TDPAC) method, in the temperature range 78-675 K. The obtained value of 8.6 (3) T at room temperature is in good agreement with the previously reported measurements for similar Hf concentrations in Ni. X-ray powder diffraction (XRPD) experiments confirmed that small atomic concentrations of Hf atoms (<1 at.%) mainly substitute on Ni lattice sites in the fcc crystal lattice without forming any intermetallic phase. In addition, ab-initio calculation using all-electron augmented plane waves plus local orbitals (APW+lo) formalism is performed and the obtained result for the hyperfine magnetic field at Ta site is in accordance with the measurement.

  7. Quantum beats in the 3γ annihilation decay of Positronium observed by perturbed angular distribution

    NASA Astrophysics Data System (ADS)

    Ivanov, Eugeniu; Vata, Ion; Dudu, Dorin; Rusen, Ion; Stefan, Nitisor

    2008-10-01

    We have applied conventional Time Differential Perturbed Angular Correlation (TDPAC) method to observe the anisotropy oscillations in the 3γ annihilation decay of polarized Positronium in a weak magnetic field. The effect, as predicted theoretically and experimentally demonstrated by Barishevsky et al. [V.G. Barishevsky, O.N. Metelitsa, V.V. Tikhomirov, Oscillations of the positronium decay γ-quantum angular distribution in a magnetic field, J. Phys. B: At. Mol. Opt. Phys.22 (1989) 2835], is induced by the coherent admixture of the m = 0 states of ortho-Positronium ( o-Ps) and para-Positronium ( p-Ps) in interaction with the magnetic field. The following experimental characteristics are to be considered: the oscillation frequency corresponds to the difference in energy of the Ps atom levels in magnetic field and is proportional with H2; in a fixed geometry the modulation depth (oscillations amplitude) depends on the mean positron polarization; privileged angles of the polarization vector, magnetic field and detectors are required for optimizing the observed oscillations amplitude. The normalized difference spectrum function ( R( t)) obtained from time spectra measured in vacuum and in different gaseous atmospheres (Ar, H 2, N 2) have the oscillations amplitude constant and we conclude that the Ps atoms are not fully thermalized over a time interval of about 400 ns. The R( t) functions obtained for o-Ps annihilation decays, in dry air or Ar-O mixture, have the oscillations amplitude time dependent due, probably, to the paramagnetism of the Oxygen molecules.

  8. Hyperfine interaction measurements in LaCrO3 and LaFeO3 perovskites using perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Dogra, R.; Junqueira, A. C.; Saxena, R. N.; Carbonari, A. W.; Mestnik-Filho, J.; Moralles, M.

    2001-06-01

    The perturbed angular correlation (PAC) technique was used to study the hyperfine interactions in the antiferromagnetic and paramagnetic regions of the distorted perovskites LaCrO3 and LaFeO3. The dilute 111In-->111Cd nuclear probes were introduced into the samples through a chemical process. The present measurements cover the temperature ranges from 15 to 848 K for LaCrO3 and 77 to 1324 K for LaFeO3. Two distinct electric-quadrupole interactions were observed in each compound. The lower quadrupole frequency was assigned to the transition-metal atom site while the higher frequency was attributed to the lanthanum site in both cases. Temperature dependence of the electric-quadrupole interaction parameters indicated structural phase transitions at around 512 and 1223 K, respectively, in LaCrO3 and LaFeO3. The phase transitions were associated with the change from an orthorhombic to rhombohedral structure and characterized by a sudden increase in the electric field gradient Vzz and a decrease in the asymmetry parameter η for both sites. PAC spectra measured below the Néel temperature revealed that at 0 K the supertransferred magnetic hyperfine field on 111Cd at the Cr site in LaCrO3 (2.4 T) is much smaller than at the Fe site in LaFeO3 (19.4 T). The magnetic field on 111Cd at La sites in both compounds is of the order of 0.3 T. Additional measurements were made to determine the magnetic hyperfine field using the probe nucleus 140La-->140Ce. The result reconfirmed that a relatively weak hyperfine field is supertransferred to the probe atoms at La sites.

  9. 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.

  10. Oxygen ordering in the high-Tc superconductor HgBa2CaCu2O6+δ as revealed by perturbed angular correlation

    NASA Astrophysics Data System (ADS)

    Mendonça, T. M.; Correia, J. G.; Haas, H.; Odier, P.; Tavares, P. B.; da Silva, M. R.; Lopes, A. M. L.; Pereira, A. M.; Gonçalves, J. N.; Amaral, J. S.; Darie, C.; Araujo, J. P.

    2011-09-01

    Lattice sites and collective ordering of oxygen atoms in HgBa2CaCu2O6+δ were studied using the perturbed angular correlation (PAC) technique at ISOLDE/CERN. The electric field gradients (EFG) at 199mHg nuclei have been measured as functions of oxygen doping on the Hg planes, above and below Tc. In comparison with the results obtained for oxygen and fluorine doping in Hg-1201, the analysis shows a different oxygen ordering exhibited by Hg-1212. Moreover, for all studied cases, the experimental results show that at a local scale there is non uniform oxygen distribution. A series of ab initio EFG calculations allowed to infer that at low concentrations, regions without oxygen coexist with regions where O2δ dumbbell molecules are located at the center of the Hg mesh. On the other side, at high concentrations, O2δ dumbbell molecules coexist with single Oδ atoms occupying the center of the Hg mesh. The present results suggest that oxygen sits on the Hg planes in the form of a molecule and not as a single atom.

  11. 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.

  12. Time differential perturbed angular correlation (TDPAC) studies of the 133Ba ion uptake in bone crystals.

    PubMed

    Rimbert, J N; Kellershohn, C; Dumas, F; Hubert, C

    1981-03-01

    TDPAC measurements of the 356-81 keV gamma-ray cascade resulting from electron capture decay of 133Ba have been performed at room temperature on BaCl2 (aqueous solution and polycrystalline powder), and on samples where the 133Ba nucleus is bound to bone powder, and also to synthesised hydroxylapatite, all after absorption in vitro. As expected, the angular correlation is not perturbed in the solution. However, in the polycrystalline chloride the time dependence of the anisotropy of the cascade of 133Cs nuclide indicates that the decaying nucleus undergoes electric interactions due to different electric field gradients acting at the site of the nucleus. In 133Ba-bone powder the results show a static quadrupolar interaction differing with the absorption contact time during sample preparation, indicating that depth of 133Ba ion fixation in the bone crystal is dependent on this contact time. These results seem to be confirmed by the TDPAC measurements performed on 133Ba-hydroxylapatite samples where the contact times for absorption of active-ion 133Ba and hydroxylapatite in suspension were very different. PMID:7220599

  13. Studies of point-defect interactions in solids using perturbed angular correlations

    SciTech Connect

    Schuhmann, R.B.

    1988-01-01

    Vacancy defect production and migration in {sup 111}In doped Au, Pt and Ni following plastic deformation are studied via {sup 111}Cd perturbed {gamma}-{gamma} angular correlations (TDPAC). In all three metals, deformation produces the same defect species as are seen following irradiation. In Au, a particular In-vacancy complex which is probably a trapped divacancy exists in two distinct configurations. Thermal conversion from one configuration to the other occurs near 200K. In Pt, an In-vacancy complex exhibits a strongly temperature dependent electric field gradient, indicating the presence of local resonant modes. In Ni, a relaxed In-trivacancy complex forms via simple, single-step trapping of a migrating trivacancy. Once formed, the In-trivacancy complex in Ni can trap up to four guest H or D atoms. These are bound to the complex with an energy of {approximately}0.5 eV, irrespective of isotopic mass. By monitoring the damping of the TDPAC precession not associated with a bound defect, the author observed release of untrapped interstitial H from the lattice. These experiments give a consistent, microscopic picture of H diffusion and release from Ni. The use of BaF{sub 2} scintillators allows for an eightfold improvement in TDPAC time resolution. This makes possible experiments in systems previously inaccessible due to large precessional frequencies. The author demonstrates the utility of BaF{sub 2} in several examples, including {sup 100}RhNi, {sup 99}TcFe, {sup 101}RuFe, {sup 100}RhCo and {sup 100}RhFe, systems which had not been studied previously due to time resolution limitation. The Larmor frequency for {sup 100}RhFe, 5565 Mrad/s, is the highest frequency ever measured via TDPAC.

  14. Magnetic and Structural Properties of LANTHANUM(2-X) Strontium(x) Copper OXYGEN(4+DELTA) Studied with Time - Perturbed Angular Correlations

    NASA Astrophysics Data System (ADS)

    Saylor, Janet Marie

    Structural and magnetic properties of the high temperature superconductor La_{2-x}Sr_{x} CuO_{4-y} have been studied with ^{111} In/^{111}Cd perturbed angular gammagamma-correlations (PAC). In these measurements ppm of the radioactive probe, ^{111}In, is diffused into small samples by heat treatment. During the 2.8 day half-life of ^{111}In, the hyperfine spectrum of the I = 5/2, 85 ns. excited state of ^{111}Cd can be studied. A number of complex combined magnetic-dipole -electric-quadrupole interactions are observed. These depend simply on the sample preparation which controls the types and concentration of oxygen defects which exist in the sample. In particular, we have found that vacuum annealing results in a unique PAC spectrum. In this case, which only occurs when the samples are nearly exactly oxygen stoichiometric, the ^{111}Cd probe sits at the La site with no oxygen defects nearby. The principle axis of the electric field gradient ( omega_{o} = 240 Mrad/s) is found to be nearly parallel to the tetragonal c-axis and perpendicular to the hyperfine field ( omega_{L} = 10 Mrad/s). The temperature dependence and orientation of the hyperfine field, the electric field gradient and its asymmetry parameter (eta~ 0.1) have been studied for lightly doped La_{2-x }Sr_{x}CuO _4. We found first that hyperfine field is proportional to bulk magnetization, and second that eta is proportional orthorhombic distortion (To = 530 K). This unique sensitivity of our probe to both the magnetic and structural phase transitions in La _2CuO_{4+delta }, combined with the microscopic information on oxygen stoichiometry it can provide, have made ^{111}In/^{111 }Cd PAC ideal for studies of complex phase diagram of La_{2-x}Sr _{x}CuO _4. Results from these investigations include the first microscopic determination of the oxygen stoichiometry of La_{2-x}Sr _{x}CuO _4 and observation of the maximum Neel temperature; measurement of the magnetic critical exponent, beta = 0.50(4), and the

  15. Resonance and absorption spectra of the Schwarzschild black hole for massive scalar perturbations: A complex angular momentum analysis

    SciTech Connect

    Decanini, Yves; Raffaelli, Bernard; Folacci, Antoine

    2011-10-15

    We reexamine some aspects of scattering by a Schwarzschild black hole in the framework of complex angular momentum techniques. More precisely, we consider, for massive scalar perturbations, the high-energy behavior of the resonance spectrum and of the absorption cross section by emphasizing analytically the role of the mass. This is achieved (i) by deriving asymptotic expansions for the Regge poles of the S-matrix and then for the associated weakly damped quasinormal frequencies and (ii) by taking into account the analytic structure of the greybody factors which allows us to extract by resummation the physical information encoded in the absorption cross section.

  16. Perturbed Angular Correlation of the stretched cascade in the decay of 180mHf using a digital spectrometer

    NASA Astrophysics Data System (ADS)

    Jäger, Markus; Butz, Tilman

    2012-05-01

    We report on the measurement of the nuclear quadrupole interaction (NQI) at Hf sites using the nuclear probe 180mHf in HfF4·HF·2H2O at 300 K by exploiting all possible start quanta in the stretched cascade with a digital Time Differential Perturbed Angular Correlation (TDPAC) spectrometer. With conventional spectrometers, multiple prompt start signals would paralyze the router. The gain in coincidence rate is about a factor of 5 compared to a conventional spectrometer using a single start only. With multiple starts 180mHf is a promising new isomeric nuclear probe in TDPAC experiments. As an additional feature we implemented the possibility to measure up to four cascades simultaneously in order to save data collection time or to measure isobaric contaminations like 111mCd and 111In.

  17. Nuclear quadrupole interaction at 181Ta in hafnium dioxide fiber: Time differential perturbed angular correlation measurements and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Das, P.; Guin, R.; Das, S. K.

    2012-09-01

    The thermal behavior of hafnium dioxide fiber has been investigated with the aid of time differential perturbed angular correlation (TDPAC) technique along with XRD and SEM measurements. This study has proved a good thermal stability of the fibrous material up to 1173 K and the fiber loses its crystallinity to a meager extent at 1673 K. No phase transition has been observed up to 1673 K in this fiber. TDPAC parameters for the HfO2 fiber annealed at 1173 K are ωQ=124.6 (3) Mrad/s and η=0.36 (1). These values remain unaltered for the HfO2 fiber annealed even at 1673 K. Electronic structure calculations based on the density functional theory (DFT) for HfO2 doped with tantalum impurity have been performed and the calculated EFG parameters are in reasonable agreement with the experimental values.

  18. PAC studies on impurities in ZnO

    NASA Astrophysics Data System (ADS)

    Deubler, S.; Meier, J.; Schütz, R.; Witthuhn, W.

    1992-01-01

    Acceptor-donor pairs in ZnO are studied by the perturbed angular correlation spectroscopy (PAC) using radioactive 111In/ 111Cd probe atoms. In undoped ZnO the trapping of O-vacancies as well as the trapping of Zn-interstitials at the probe atoms which are located at substitutional Zn sites is observed after different sample treatments. In Cu-, Li-, and Na-doped ZnO the acceptor impurities form complexes with the In donors. The structure of these complexes is given and compared with theoretical calculations.

  19. Oxidation of Hafnium and Diffusion of Hafnium Atoms in Hexagonal Close-Packed Hafnium; Microscopic Investigations by Perturbed Angular Correlations

    NASA Astrophysics Data System (ADS)

    Dey, Chandi C.

    2012-11-01

    Time-differential perturbed angular correlation (TDPAC) studies in hafnium metal (~5%Zr) have been carried out at different temperatures. It is found that hafnium metal on heating at 873 K continuously for two days in air, transforms partially and abruptly to HfO2 while no component of oxide has been observed for heating up to 773 K and during initial heating at 873 K for 1 day. This result is strikingly different to that expected from the Arrhenius theory. Also, a strong nuclear relaxation effect has been observed at 873 K due to rapid fluctuation of hafnium atoms in hexagonal closepacked (hcp) hafnium. At this temperature, ~ 5% probe nuclei experience static perturbation due to monoclinic HfO2, ~ 50% experience fluctuating interaction, and ~ 5% produce static defect configuration of hcp hafnium. With lowering of temperature, defect configurations of hafnium increase at the cost of fluctuating interaction. An almost total fluctuating interaction observed in hcp hafnium at a temperature much lower than its melting point is another interesting phenomenon.

  20. Electric quadrupole interactions in nano-structured SnO 2 as measured with PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramos, J. M.; Carbonari, A. W.; Costa, M. S.; Saxena, R. N.

    2010-04-01

    Measurements of the electric quadrupole interaction were used to characterize pure and cobalt-doped samples of SnO2 prepared by the sol-gel method. Perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111In-111Cd probe nuclei was employed for these measurements. A methodology was developed for sample preparation that were prepared by sol-gel method from pure metallic Sn (99.9999%) and Co (99.9998%) as starting materials. Carrier-free 111In was added to the precursor sol-gel solution prior to the formation of gel. PAC measurements were carried out to follow the formation of the SnO2. PAC measurements were carried out in the temperature range from 10 k to 1123 K and the results show that the electric quadrupole frequency depends on the annealing temperature.

  1. PAC spectroscopy of electronic ceramics

    SciTech Connect

    Gardner, J.A.; Wang, Ruiping; Schwenker, R.; Evenson, W.E.; Rasera, R.L.; Sommers, J.A.

    1991-12-31

    Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.

  2. PAC spectroscopy of electronic ceramics

    SciTech Connect

    Gardner, J.A.; Wang, Ruiping; Schwenker, R. . Dept. of Physics); Evenson, W.E. . Dept. of Physics and Astronomy); Rasera, R.L. . Dept. of Physics); Sommers, J.A. )

    1991-01-01

    Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.

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

    PubMed

    Jäger, Markus; Iwig, Kornelius; Butz, Tilman

    2011-06-01

    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 γ-γ correlation diagrams. Tests were performed which showed that the time resolution using a (60)Co source with energy window set at 1.17 MeV and 1.33 MeV is 265 ps with LaBr(3)(Ce) scintillators and 254 ps with BaF(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 (44)Ti in rutile source and a positron lifetime measurement using (22)Na. The maximum possible data rate of the spectrometer is 1.1 × 10(6) γ quanta per detector and second. PMID:21721728

  4. 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.

  5. Interaction of positronium atoms, with paramagnetic molecules, measured by perturbed angular distribution in 3γ annihilation decay

    NASA Astrophysics Data System (ADS)

    Ivanov, Eugeniu; Vata, Ion; Teodorian, Stefan; Rusen, Ion; Stefan, Nitisor

    2009-01-01

    Positronium in the triplet spin state (S = 1) decays by 3γ annihilation having a life time of about 140 ns in vacuum. Positronium annihilation is affected by magnetic fields which mix the M = 0 state of ortho-positronium with the M = 0 state of para-positronium. The mixing fraction depends on the magnetic field intensity and causes quantum beats in the time distribution of γ annihilation decay. This effect was predicted by Barishevsky et al. [V.G. Barishevsky, O.N. Metelitsa, V.V. Tikhomirov, J. Phys. B Atom. Mol. Opt. Phys. 22 (1989) 2835]. The time differential perturbed angular correlation method (TDPAC), combined with long-lived positron life time spectroscopy (PLTS), has been used to observe these quantum beats. It is found that the characteristics of the annihilation time distribution are not influenced by the presence of diamagnetic species such as Ar, N2 and H2 but are affected by the presence of the paramagnetic O2 molecule. Our results are encouraging in developing a new method for investigating magnetic fields on an atomic scale.

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

    NASA Astrophysics Data System (ADS)

    Jäger, Markus; Iwig, Kornelius; Butz, Tilman

    2011-06-01

    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 γ-γ correlation diagrams. Tests were performed which showed that the time resolution using a 60Co source with energy window set at 1.17 MeV and 1.33 MeV is 265 ps with LaBr3(Ce) scintillators and 254 ps with BaF2 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 44Ti in rutile source and a positron lifetime measurement using 22Na. The maximum possible data rate of the spectrometer is 1.1 × 106 γ quanta per detector and second.

  7. PACS industry in Korea

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Joung

    2002-05-01

    PACS industry in Korea has been rapidly growing, since government had supported collaborative PACS project between industry and university hospital. In the beginning, PACS industry had focused on developing peripheral PACS solutions, while the Korea PACS society was being formed. A few companies had started developing and installing domestic large-scale full-PACS system for teaching hospitals. Several years later, many hospitals have installed full-PACS system with national policy of reimbursement for PACS exams in November 1999. Both experiences of full-PACS installation and national policy generated tremendous intellectual and technological expertise about PACS at all levels, clinical, hospital management, education, and industrial sectors. There are now more than 20 domestic PACS companies. They have enough experiences which are capable of installing a truly full-PACS system for large-scale teaching hospitals. As an example, a domestic company had installed more than 40 full-PACS systems within 2-3 years. Enough experiences of full-PACS installation in Korea lead PACS industry to start exporting their full-PACS solutions. However, further understanding and timely implementation of continuously evolving international standard and integrated healthcare enterprise concepts may be necessary for international leading of PACS technologies for the future.

  8. Time-differential perturbed angular correlation study of the electric field gradient in Ti2Rh MoSi2-type compound

    NASA Astrophysics Data System (ADS)

    Wodniecki, P.; Kulińska, A.; Wodniecka, B.

    The electric field gradient (EFG) at the 181Hf→181Ta site in Ti2Rh C11 b -type compound was measured as a function of temperature using time-differential perturbed angular correlation (TDPAC) technique. The room temperature results show one EFG with the parameters of: ν Q =336(1) MHz→V zz =5.9×1017 V cm-2, η=0.1. Very week linear temperature dependence of this EFG was measured with the slope of 3.6 (2)×10-5 K-1. The results are compared with those for other isostructural compounds.

  9. Time-differential perturbed angular correlation study of the electric field gradient in Ti2Rh MoSi2-type compound

    NASA Astrophysics Data System (ADS)

    Wodniecki, P.; Kulińska, A.; Wodniecka, B.

    2007-06-01

    The electric field gradient (EFG) at the 181Hf→181Ta site in Ti2Rh C11 b -type compound was measured as a function of temperature using time-differential perturbed angular correlation (TDPAC) technique. The room temperature results show one EFG with the parameters of: ν Q = 336(1) MHz→V zz =5.9 × 1017 V cm - 2, η = 0.1. Very week linear temperature dependence of this EFG was measured with the slope of 3.6 (2) × 10 - 5 K - 1. The results are compared with those for other isostructural compounds.

  10. PAC investigation on the Zr-rich region of the PZT phase diagram

    NASA Astrophysics Data System (ADS)

    Alonso, R. E.; Ayala, A. P.; López García, A. R.; Eiras, J. A.

    2007-02-01

    Previous studies using perturbed angular correlation (PAC) spectroscopy in the PbZr 1-xTi xO 3 (PZT) family of compounds show that whereas PbZrO 3 is characterized by a single probes site with a very well-defined hyperfine interaction, in PZT with x⩾0.1 the probes occupy two distributed sites. In this work, we investigate the Zr-rich region of the PZT phase diagram from x=0.02 up to x=0.08 using PAC in order to correlate the hyperfine parameters with the antiferroelectric-ferroelectric phase transition reported to occur at x=0.05. Two static electric quadrupole interactions, one of them fairly distributed, were detected over the whole Ti concentration range, and an abrupt change in the hyperfine parameters for 0.02< x<0.04 is observed. The behaviour of these parameters and the existence of two probe sites is discussed.

  11. Three-hadron angular correlations in high-energy proton-proton and nucleus-nucleus collisions from perturbative QCD

    SciTech Connect

    Ayala, Alejandro; Ortiz, Antonio; Paic, Guy; Jalilian-Marian, Jamal; Magnin, J.; Tejeda-Yeomans, Maria Elena

    2011-08-15

    We study three-hadron azimuthal angular correlations in high-energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider at midrapidity. We use the leading-order parton matrix elements for 2{yields}3 processes and include the effect of parton energy loss in the quark-gluon plasma using the modified fragmentation function approach. For the case when the produced hadrons have either the same or not too different momenta, we observe two away-side peaks at 2{pi}/3 and 4{pi}/3. We consider the dependence of the angular correlations on energy loss parameters that have been used in studies of single inclusive hadron production at RHIC. Our results on the angular dependence of the cross section agree well with preliminary data by the PHENIX Collaboration. We comment on the possible contribution of 2{yields}3 processes to dihadron angular correlations and how a comparison of the two processes may help characterize the plasma further.

  12. Local probe studies of Fe hyperfine field in CaFe2As2 by time differential perturbed angular distribution (TDPAD) spectroscopy and ab initio methods

    NASA Astrophysics Data System (ADS)

    Mohanta, S. K.; Mishra, S. N.; Davane, S. M.; Kumar, Neeraj; Thamizhavel, A.; Layek, S.; Hossain, Z.; Srivastava, S. K.

    2013-03-01

    Applying the γ-ray perturbed angular distribution technique we have measured the magnetic hyperfine field and spin relaxation time of recoil implanted 54Fe in single and polycrystalline CaFe2As2 over the temperature range 20-360 K, encompassing both tetragonal and orthorhombic structural phases of the material. The magnetic response of Fe in the high temperature tetragonal phase (T ⩾ 180 K), show Curie-Weiss type local susceptibility and Korringa like spin relaxation, reflecting the presence of localized moment on Fe. In the orthorhombic phase, the spin rotation spectra of 54Fe show two magnetic hyperfine field components, both exhibiting quasi two dimensional magnetic ordering. The experimentally measured hyperfine field and Fe moment show good agreement with results obtained from ab initio calculations performed within the frame work of local spin density approximation (LSDA).

  13. Online time-differential perturbed angular correlation study with an 19O beam - Residence sites of oxygen atoms in highly oriented pyrolytic graphite

    NASA Astrophysics Data System (ADS)

    Sato, W.; Ueno, H.; Watanabe, H.; Miyoshi, H.; Yoshimi, A.; Kameda, D.; Ito, T.; Shimada, K.; Kaihara, J.; Suda, S.; Kobayashi, Y.; Shinohara, A.; Ohkubo, Y.; Asahi, K.

    2008-01-01

    The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe 19F, the β- decay product of 19O (t1/2 = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, ∣Vzz∣ = 2.91(17) × 1022 V m-2, suggests that the incident 19O atoms are stabilized at an interlayer position with point group C3v. Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive 19O beam.

  14. Dynamic lattice distortions in Sr2RuO4: microscopic studies by perturbed angular correlation spectroscopy and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Mishra, S. N.; Rots, M.; Cottenier, S.

    2010-09-01

    Applying time differential perturbed angular correlation (TDPAC) spectroscopy and ab initio calculations, we have investigated possible lattice instabilities in Sr2RuO4 by studying the electric quadrupole interaction of a 111Cd probe at the Ru site. We find evidence for a dynamic lattice distortion, revealed from the observations of: (i) a rapidly fluctuating electric-field gradient (EFG) tensor showing non-Arrhenius relaxation, (ii) an anomalous temperature dependence of the quadrupole interaction frequency, and (iii) a monotonic increase of the EFG asymmetry (η) below 300 K. We argue that the observed dynamic lattice distortion is caused by strong spin fluctuations associated with the inherent magnetic instability in Sr2RuO4.

  15. Dynamic lattice distortions in Sr2RuO4: microscopic studies by perturbed angular correlation spectroscopy and ab initio calculations.

    PubMed

    Mishra, S N; Rots, M; Cottenier, S

    2010-09-29

    Applying time differential perturbed angular correlation (TDPAC) spectroscopy and ab initio calculations, we have investigated possible lattice instabilities in Sr(2)RuO(4) by studying the electric quadrupole interaction of a (111)Cd probe at the Ru site. We find evidence for a dynamic lattice distortion, revealed from the observations of: (i) a rapidly fluctuating electric-field gradient (EFG) tensor showing non-Arrhenius relaxation, (ii) an anomalous temperature dependence of the quadrupole interaction frequency, and (iii) a monotonic increase of the EFG asymmetry (η) below 300 K. We argue that the observed dynamic lattice distortion is caused by strong spin fluctuations associated with the inherent magnetic instability in Sr(2)RuO(4). PMID:21386555

  16. PACS for GU radiology

    NASA Astrophysics Data System (ADS)

    Hayrapetian, Alek S.; Barbaric, Zoran L.; Weinberg, Wolfram S.; Chan, Kelby K.; Loloyan, Mansur; Taira, Ricky K.; Huang, H. K.

    1991-07-01

    The authors have developed a PACS module for genito-urinary radiology. This module is based on image acquisition subsystem, database and storage server/cluster controllers, communication networks, display workstation and local database, and dedicated digitizer and printer. The design guideline for this system is generality and flexibility. As such this module serves as a prototype for future PACS module designs.

  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. Monte Carlo Simulations of PAC-Spectra as a General Approach to Dynamic Interactions

    NASA Astrophysics Data System (ADS)

    Danielsen, Eva; Jørgensen, Lars Elkjær; Sestoft, Peter

    Time Dependent Perturbed Angular Correlations of γ-rays (PAC) can be used to study hyperfine interactions of a dynamic nature. However, the exact effect of the dynamic interaction on the PAC-spectrum is sometimes difficult to derive analytically. A new approach based on Monte Carlo simulations is therefore suggested, here implemented as a Fortran 90 program for simulating PAC spectra of dynamic electric field gradients of any origin. The program is designed for the most common experimental condition where the intermediate level has spin 5/2, but the approach can equally well be used for other spin states. Codes for 4 different situations have been developed: (1) Rotational diffusion by jumps; used as a test case. (2) Jumps between two states with different electric field gradients, different lifetimes and different orientations of the electric field gradient principal axes. (3) Relaxation of one state to another. (4) Molecules adhering to a surface with random rotational jumps around the axis perpendicular to the surface. To illustrate how this approach can be used to improve data-interpretation, previously published data on 111mCd-plastocyanin and 111Ag-plastocyanin are re-considered. The strength of this novel approach is its simplicity and generality so that other dynamic processes can easily be included by only adding new program units describing the random process behind the dynamics. The program is hereby made publicly available.

  19. 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.

  20. Magnetic behavior of La-doped Fe3O4 studied by perturbed angular correlation spectroscopy with 111Cd and 140Ce

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    In this paper, the local magnetic properties of La-doped Fe3O4 (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 111In(111Cd) and 140La(140Ce) as probe nuclei. Results for the temperature dependence of the magnetic hyperfine field (Bhf) 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 (TC) was determined (TC ˜ 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 TV ˜ 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 Fe2+ and Fe3+ ions in the two regions of NP.

  1. 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.

  2. The future of PACS.

    PubMed

    Nagy, Paul G

    2007-07-01

    How will the future of picture archiving and communication systems (PACS) look, and how will this future affect the practice of radiology? We are currently experiencing disruptive innovations that will force an architectural redesign, making the majority of today's commercial PACS obsolete as the field matures and expands to include imaging throughout the medical enterprise. The common architecture used for PACS cannot handle the massive amounts of data being generated by even current versions of computed tomography and magnetic resonance scanners. If a PACS cannot handle today's technology, what will happen as the field expands to encompass pathology imaging, cone-beam reconstruction, and multispectral imaging? The ability of these new technologies to enhance research and clinical care will be impaired if PACS architectures are not prepared to support them. In attempting a structured approach to predictions about the future of PACS, we offer projections about the technologies underlying PACS as well as the evolution of standards development and the changing needs of a broad range of medical imaging. Simplified models of the history of the PACS industry are mined for the assumptions they provide about future innovations and trends. The physicist frequently participates in or directs technical assessments for medical equipment, and many physicists have extended these activities to include imaging informatics. It is hoped that by applying these speculative but experienced-based predictions, the interested medical physicist will be better able to take the lead in setting information technology strategies that will help facilities not only prepare for the future but continue to enjoy the benefits of technological innovations without disruptive, expensive, and unexpected changes in architecture. A good PACS strategy can help accelerate the time required for innovations to go from the drawing board to clinical implementation. PMID:17821975

  3. 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.

  4. Perturbed Angular Correlation Study of the Static and Dynamic Aspects of Cadmium and Mercury Atoms Inside and Attached to a C60 Fullerene Cage

    NASA Astrophysics Data System (ADS)

    Das, Satyendra K.; Guin, Rashmohan; Banerjee, Debasish; Johnston, Karl; Das, Parnika; Butz, Tilman; Amaral, Vitor S.; Correia, Joao G.; Barbosa, Marcelo B.

    2014-11-01

    30 keV 111mCd and 50 keV 199mHg beams from ISOLDE were used to implant on preformed targets of C60 with a thickness of 1 mg cm-2. Endofullerene compounds, viz. 111mCd@C60 and 199mHg@C60 formed during implantation were separated by filtration through micropore filter paper followed by solvent extraction. Dried samples of the endofullerene compounds were counted for the time differential perturbed angular correlation (TDPAC) measurement using the coincidence of the 151 - 245 keV cascade of 111mCd and the 374 - 158 keV cascade of 199mHg on a six LaBr3(Ce) detector system coupled with digital electronics. The results for 111mCd@C60 indicate a single static component (27%) and a fast relaxing component (73%), the latter implying that the cadmium atom moves rapidly inside the cage at room temperature. The quadrupole interaction frequency and asymmetry parameter of the cadmium atom occupying the static site in C60 are wQ=8.21(36) Mrad s-1 and η = 0.41(9), respectively. The fast relaxation constant is 0.0031(4) ns-1. Similarly, mercury atoms also exhibit a single static and a fast component. The static site has a quadrupole frequency wQ=283.0(12.4) Mrad s-1 and η =0 with a fraction of 30%. The fast relaxation constant is 0.045(8) ns-1 with a fraction of 70%, very similar to that of cadmium.

  5. 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.

  6. Electric field gradient in nanostructured SnO2 studied by means of PAC spectroscopy using 111Cd or 181Ta as probe nuclei

    NASA Astrophysics Data System (ADS)

    Ramos, Juliana Marques; Martucci, Thiago; Carbonari, Artur Wilson; de Souza Costa, Messias; Saxena, Rajendra Narain; Vianden, Reiner

    2013-05-01

    Electric quadrupole interactions were studied in pure and Mn-doped powder samples and thin films of SnO2 using perturbed γγ angular correlation spectroscopy (PAC). The powder samples were prepared by Sol gel method and the thin film were prepared on the Si (100) substrate by sputtering technique using Sn in the oxygen atmosphere. The samples were characterized by x-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. The thickness of the film was 100 nm. The average particle size of the SnO2 powder samples was determined to be smaller than 60 nm. The radioactive 111In and 181Hf tracers were introduced in the powder samples during the sol gel chemical process. Radioactive 111In was implanted on the SnO2 thin films using the University of Bonn ion implanter (BONIS). PAC measurements were carried out in a four BaF2 detector spectrometer in the temperature range of 77-973 K for samples annealed at different temperatures. The PAC results for both nuclear probes show the presence of two electric quadrupole interactions. The major fractions in both cases correspond to the substitutional sites in the rutile phase of SnO2. The results are compared with previous PAC measurements.

  7. PACS pitfalls and bottlenecks

    NASA Astrophysics Data System (ADS)

    Huang, H. K.; Lou, Shyhliang A.; Wong, Albert W. K.

    1997-05-01

    PACS pitfalls are mostly created from human error, whereas bottlenecks are due to imperfect design in either the PACS or image acquisition devices. These drawbacks can only be realized through accumulated clinical experience. Pitfalls due to human error are often initiated at imaging acquisition devices and at workstations. Three major errors at the acquisition devices are entering wrong input parameters, stopping an image transmission process improperly, and incorrect patient positioning. The error occurring most often at the workstation happens when the user enters too many key strokes or clicks the mouse too often before the workstation can respond. Other pitfalls at the workstation unrelated to human error are missing location markers in a CT or MR scout view, images displayed with unsuitable look-up-tables, and white boarders in CR images due to x-ray collimation. Pitfalls created due to human intervention can be minimized by a better quality assurance program and periodic in-service training, and by interfacing image acquisition devices to the HIS/RIS. Bottlenecks affecting the PACS operation include network contention; CR, CT, and MR images stacked up at acquisition devices; slow response from workstations; and long delays for image retrieval from the long term archive. Bottlenecks can be alleviated by improving the system architecture, re- configuring the networks, and streamlining operational procedures through a gradual understanding of the clinical environment. We have identified most of the pitfalls and bottlenecks discussed above in our hospital-integrated PACS based on the past two years of clinical experience. This paper categorizes some of these problems, illustrates their effect on PACS operations, and suggests methods for circumventing them.

  8. 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

  9. 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.

  10. '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 ].

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. RIS minus PACS equals film.

    PubMed

    Tellis, Wyatt M; Andriole, Katherine P; Jovais, Christopher S; Avrin, David E

    2002-01-01

    Web-based integration methods can be used to resolve a fundamental issue in the transition from film to a picture archiving and communication system (PACS): the identification of relevant prior studies only available on film. Even in the most ambitious conversions from a film-based environment to PACS, there are issues regarding prior studies not on PACS. Failure to compare with prior exams is one of the known risk factors for malpractice in radiology. While most commercial PACS systems today have some degree of RIS integration, knowledge of prior studies is usually limited to an awareness of studies in the PACS. On the other hand, most RIS systems today do not or cannot distinguish between studies on film and those in PACS. We made the observation, from a set theory perspective, that in general: Therefore we sought to create a system that would query both the RIS and PACS and reconcile the results using the above set operation. The query is initiated from a display station via the invocation of a Web browser installed on that station. The process of starting the browser is implemented using a scripting language provided by the workstation vendor, though the use of other mechanisms, such as the CCOW (Clinical Context Object Workgroup) or IHE (RSNA Integrated Healthcare Enterprise) interfaces, can be supported by this architecture. The medical record number, which identifies the current patient and is the primary parameter of the query, is passed as part of the URL (Universal Resource Locator) used to launch the browser. Once running, the browser connects to a Web server that hosts a JSP (Java Server Page) page that performs a DICOM query of the PACS and an HL7 query of the RIS, and then collates the results using the set operation described above. Both the DICOM and HL7 functionality are provided by Java-based toolkits developed in house. The results are returned to the client's browser as a standard HTML page with a tabular format detailing which studies are on

  17. Urological diagnosis using clinical PACS

    NASA Astrophysics Data System (ADS)

    Mills, Stephen F.; Spetz, Kevin S.; Dwyer, Samuel J., III

    1995-05-01

    Urological diagnosis using fluoroscopy images has traditionally been performed using radiographic films. Images are generally acquired in conjunction with the application of a contrast agent, processed to create analog films, and inspected to ensure satisfactory image quality prior to being provided to a radiologist for reading. In the case of errors the entire process must be repeated. In addition, the radiologist must then often go to a particular reading room, possibly in a remote part of the healthcare facility, to read the images. The integration of digital fluoroscopy modalities with clinical PACS has the potential to significantly improve the urological diagnosis process by providing high-speed access to images at a variety of locations within a healthcare facility without costly film processing. The PACS additionally provides a cost-effective and reliable means of long-term storage and allows several medical users to simultaneously view the same images at different locations. The installation of a digital data interface between the existing clinically operational PACS at the University of Virginia Health Sciences Center and a digital urology fluoroscope is described. Preliminary user interviews that have been conducted to determine the clinical effectiveness of PACS workstations for urological diagnosis are discussed. The specific suitability of the workstation medium is discussed, as are overall advantages and disadvantages of the hardcopy and softcopy media in terms of efficiency, timeliness and cost. Throughput metrics and some specific parameters of gray-scale viewing stations and the expected system impacts resulting from the integration of a urology fluoroscope with PACS are also discussed.

  18. Technical aspects of PACS in Korea

    NASA Astrophysics Data System (ADS)

    Kim, JongHyo

    2002-05-01

    Korea is one of the fastest growing countries in the number of filmless hospitals. More than 70 hospitals have converted to filmless environments by adopting full PAC systems during the last two years. The patient care environment in Korean hospitals was not favorable to PACS implementation. In many out patient clinics, doctors had to see more than hundred patients a day. It was not rare for a radiologist to read several hundred of exams a day. Also, the PACS teams were mandated to acquire full scale PACS capable of incorporating not only radiological images but also color images produced in other imaging departments. In order to take root in Korean environment, the PACS in Korea had to pass through some technical modifications that included introduction of recent hardware technologies and development of new software features. This paper describes various technical aspects of PAC systems in Korea that have met difficult requirements and enabled wide spread of PAC systems to real clinical practice.

  19. 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

  20. Electric Field Gradient at Nb Site in the Intermetallic Compounds Nb3X (X = AI, In, Si, Ge, Sn) Measured by PAC

    NASA Astrophysics Data System (ADS)

    Junqueira, A. C.; Carbonari, A. W.; Filho, J. Mestnik; Saxena, R. N.

    2000-02-01

    The electric field gradient (efg) at the Nb site in the intermetallic compounds Nb3X (X = Al, In, Si, Ge, Sn) was measured by the Perturbed Angular Correlation (PAC) method using the well-known gamma-gamma cascade of 133 -482 keV in 181Ta from the β- decay of 181Hf, substituting approximately 0.1 atom percent of Nb. The PAC results show that Vzz drops by nearly 40% when X changes from Al to In, and by about 25% when X changes from Si to Ge and Sn. This behavior is most probably related to the change in the degree of sp hybridization in these compounds. The Vzz values of the studied compounds do not follow the well known universal correlation for the efg's in non-cubic metals but the observed trend is well reproduced by results of ab-initio electronic structure calculations. In the case of Nb3 Al a linear temperature dependence of the quadrupole frequencies was observed in the temperature range of 6.5 to 1210 K.

  1. First-principles and time-differential γ-γ perturbed-angular-correlation spectroscopy study of structural and electronic properties of Ta-doped TiO2 semiconductor

    NASA Astrophysics Data System (ADS)

    Darriba, G. N.; Errico, L. A.; Eversheim, P. D.; Fabricius, G.; Rentería, M.

    2009-03-01

    The, time-differential γ-γ perturbed-angular-correlation (TDPAC) technique using ion-implanted H181f(→T181a) tracers was applied to study the hyperfine interactions of T181a impurities in the rutile structure of TiO2 single crystals. The experiments were performed in air in the temperature range of 300-1273 K, allowing the electric-field-gradient (EFG) tensor characterization (in magnitude, asymmetry, and orientation) at T181a probe atoms located in defect-free cation sites of the structure. The measured EFG is parallel to the [001] crystal axis, as occurs at Ti sites, but normal to the EFG orientation observed at C111d impurities in TiO2 single crystals [L. A. Errico , Phys. Rev. Lett. 89, 055503 (2002)]. In addition, ab initio calculations were performed using the full-potential augmented plane wave plus local orbital method that allow us to treat the electronic structure of the doped system and the atomic relaxations induced by the Ta impurity in a fully self-consistent way. We considered different dilutions of the doped system (using the supercell approach) and studied the electronic properties and structural atomic relaxation dependence on the charge state of the impurity. The accuracy of the calculations and the excellent agreement of the predicted magnitude, asymmetry, and orientation of the EFG tensor with the experimental results enable us to infer the EFG sign, not accessible with conventional TDPAC experiments. The comparison of the measured EFG at Ta sites with experimental and ab initio theoretical results reported in the literature at Cd, Ta, and Ti sites in TiO2 allowed us to obtain a deeper insight on the role played by metal impurities in oxide semiconductors.

  2. 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.

  3. Tracking PACS usage with open source tools.

    PubMed

    French, Todd L; Langer, Steve G

    2011-08-01

    A typical choice faced by Picture Archiving and Communication System (PACS) administrators is deciding how many PACS workstations are needed and where they should be sited. Oftentimes, the social consequences of having too few are severe enough to encourage oversupply and underutilization. This is costly, at best in terms of hardware and electricity, and at worst (depending on the PACS licensing and support model) in capital costs and maintenance fees. The PACS administrator needs tools to asses accurately the use to which her fleet is being subjected, and thus make informed choices before buying more workstations. Lacking a vended solution for this challenge, we developed our own. PMID:20830501

  4. Magnetic interactions in equi-atomic rare-earth intermetallic alloys RScGe (R = Ce, Pr, Nd and Gd) studied by time differential perturbed angular correlation spectroscopy and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Mishra, S N

    2009-03-01

    Applying the time differential perturbed angular correlation (TDPAC) technique we have measured electric and magnetic hyperfine fields of the 111Cd impurity in equi-atomic rare-earth intermetallic alloys RScGe (R = Ce, Pr and Gd) showing antiferro- and ferromagnetism with unusually high ordering temperatures. The Cd nuclei occupying the Sc site show high magnetic hyperfine fields with saturation values Bhf(0) = 21 kG, 45 kG and 189 kG in CeScGe, PrScGe and GdScGe, respectively. By comparing the results with the hyperfine field data of Cd in rare-earth metals and estimations from the RKKY model, we find evidence for the presence of additional spin density at the probe nucleus, possibly due to spin polarization of Sc d band electrons. The principal electric field gradient component Vzz in CeScGe, PrScGe and GdScGe has been determined to be 5.3 × 1021 V m-2, 5.5 × 1021 V m-2 and 5.6 × 1021 V m-2, respectively. Supplementing the experimental measurements, we have carried out ab initio calculations for pure and Cd-doped RScGe compounds with R = Ce, Pr, Nd and Gd using the full potential linearized augmented plane wave (FLAPW) method based on density functional theory (DFT). From the total energies calculated with and without spin polarization we find ferrimagnetic ground states for CeScGe and PrScGe while NdScGe and GdScGe are ferromagnetic. In addition, we find a sizable magnetic moment at the Sc site, increasing from ≈0.10 μB in CeScGe to ≈0.3 μB in GdScGe, confirming the spin polarization of Sc d band electrons. The calculated electric field gradient and magnetic hyperfine fields of the Cd impurity closely agree with the experimental values. We believe spin polarization of Sc 3d band electrons, strongly hybridized with spin polarized 5d band electrons of the rare-earth, enables a long range Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between RE 4f moments which in turn leads to high magnetic ordering temperatures in RScGe compounds.

  5. Magnetic interactions in equi-atomic rare-earth intermetallic alloys RScGe (R = Ce, Pr, Nd and Gd) studied by time differential perturbed angular correlation spectroscopy and ab initio calculations.

    PubMed

    Mishra, S N

    2009-03-18

    Applying the time differential perturbed angular correlation (TDPAC) technique we have measured electric and magnetic hyperfine fields of the (111)Cd impurity in equi-atomic rare-earth intermetallic alloys RScGe (R = Ce, Pr and Gd) showing antiferro- and ferromagnetism with unusually high ordering temperatures. The Cd nuclei occupying the Sc site show high magnetic hyperfine fields with saturation values B(hf)(0) = 21 kG, 45 kG and 189 kG in CeScGe, PrScGe and GdScGe, respectively. By comparing the results with the hyperfine field data of Cd in rare-earth metals and estimations from the RKKY model, we find evidence for the presence of additional spin density at the probe nucleus, possibly due to spin polarization of Sc d band electrons. The principal electric field gradient component V(zz) in CeScGe, PrScGe and GdScGe has been determined to be 5.3 × 10(21) V m(-2), 5.5 × 10(21) V m(-2) and 5.6 × 10(21) V m(-2), respectively. Supplementing the experimental measurements, we have carried out ab initio calculations for pure and Cd-doped RScGe compounds with R = Ce, Pr, Nd and Gd using the full potential linearized augmented plane wave (FLAPW) method based on density functional theory (DFT). From the total energies calculated with and without spin polarization we find ferrimagnetic ground states for CeScGe and PrScGe while NdScGe and GdScGe are ferromagnetic. In addition, we find a sizable magnetic moment at the Sc site, increasing from ≈0.10 μ(B) in CeScGe to ≈0.3 μ(B) in GdScGe, confirming the spin polarization of Sc d band electrons. The calculated electric field gradient and magnetic hyperfine fields of the Cd impurity closely agree with the experimental values. We believe spin polarization of Sc 3d band electrons, strongly hybridized with spin polarized 5d band electrons of the rare-earth, enables a long range Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between RE 4f moments which in turn leads to high magnetic ordering temperatures in

  6. 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.

  7. Population Association of China (PAC).

    PubMed

    Xiong, Y

    1983-12-01

    In the past 3 years, the Population Association of China, an independent, academic, and nongovernment organization established in February 1981, organized demographers throughout China to tackle the population problems that emerged in the course of the nation's socioeconomic development. Thus, by organizing and promoting exchanges, the Association did help to push forward the vigorous development of population science. Now PAC has over 500 individuals and organized units as members. It has 90 council members and 19 permanent council members. Its annual tasks and research priorities are discussed and decided by the permanent council, and then implemented in various departments and localities by its council or association members. The Population Association has organized various academic activities among demographers to study the characteristics of different periods. 1983 is an important year for the reform of social and economic systems in China. The new situation and problems brought about by the reform are bound to affect the control of population growth. Consequently, the Association decided to emphasize the control of population growth in rural areas. At the same time, the Association advocated a style of study which required people to delve into the realities of life and to investigate and study these realities thoroughly. For this purpose, 3 discussions were either financed or authorized by the Association in a single year. At the symposiums, demographers and field workers, proceeding from their country's reality and by applying the Marxist point of view, tried to find effective solutions to the demographic problems. As a result, they produced a number of valuable academic reports. In the last few years, PAC played an important role in international academic activities and exchanges. Reviewing the past and looking ahead to the future, PAC will further unite China's demographers to make new contributions to the development of the country's population science

  8. PAC Studies on Zr-Based Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Damonte, L. C.; Mendoza-Zélis, L. A.

    2004-11-01

    The Zr2Al, Zr3Al2 and Zr6NiAl2 intermetallic compounds were characterized by means of time differential perturbed angular correlation (TDPAC) and X-ray diffraction. Our interest in these Zr(Hf) aluminides comes from crystallization studies of Zr(Hf)-based bulk metallic glasses which have a wide supercooled liquid region.

  9. The Herschel-PACS grating drive mechanism: design status and prototype results

    NASA Astrophysics Data System (ADS)

    Renotte, E.; Gillis, J.-M.; Jamar, C.; Marquet, B.; Plesseria, J.-Y.; Collin, B.; Delrez, C.

    2001-09-01

    The Photodetector Array Camera and Spectrometer (PACS) is an imaging spectrometer-photometer which forms part of the science payload of the Herschel Space Observatory (formerly called FIRST), an ESA cornerstone mission (CS4) to be launched in 2007 on Ariane 5. This paper reports the present design of the motorised grating assembly for the PACS spectrometer. The PACS grating shall be capable of accurate positioning (4 arcsec) within a large angular throw (40 arcdeg) in cryogenic environment (4K). The drive mechanism is remotely controlled from the "Detector and Mechanism Controller" (DEC/MEC). Technologies of actuators, position sensors, pivots, lubricants, servo-control and cryogenic test set-up are discussed in this paper.

  10. 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.

  11. 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.

  12. Angular Cheilitis

    MedlinePlus

    ... the mouth. Overview Angular cheilitis (perlèche) is a chronic inflammatory condition of the corners of the mouth. Usually associated with a fungal ( Candidal ) or bacterial ( Staphylococcal ) infection, those ... people of all ages. Chronic pooling of saliva encourages fungal and bacterial growth, ...

  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. Picture archiving and communications systems (PACS).

    PubMed

    Honeyman, J C; Frost, M M; Huda, W; Loeffler, W; Ott, M; Staab, E V

    1994-01-01

    Although there has been a recent increase in interest in picture archiving and communications systems (PACS) topics, little has been published to assist the non-technical person in understanding the complexities of the technologies required for a PACS implementation. This issue of Current Problems in Radiology defines each PACS component and explains why each is important in a system design. PACS installations at the University of Florida are used as examples to tie the concepts together. The infrastructure required for PACS consists of the information system interfaces, networks, and databases. Information system interfaces guarantee consistent patient data across all platforms and reduce labor requirements by eliminating duplicate data entry. Data networks move information from the originating location to users around the hospital, clinic, campus, city, or world. In the PACS environment, the data consist of patient and study information as well as images and information about these images. Databases organize the data from multiple sources into a coherent package that can be queried for many different purposes, such as retrieving images, reviewing patient and study information, studying practice statistics, and performing outcomes analysis. PACS components consist of acquisition nodes, archives, and output devices. Acquisition nodes may include "digital modalities" such as CT, MRI, nuclear medicine, and computed radiography (CR), along with devices to convert from analog to digital, such as digitizers and frame grabbers. Options for archives are discussed along with configuration schemes. Output devices include both hard copy (film and paper prints) and soft copy (workstations for display and diagnosis). Finally, a description of the PACS installations at the University of Florida is presented, with comments on some of the difficulties and complexities encountered. A discussion of the cost and benefits of PACS is included, along with a forecast of the future of

  15. Gamma Ray Emission Tomography and Angular Correlation Measurements to Study the Distribution and Binding Site of Selenium.

    NASA Astrophysics Data System (ADS)

    Dahni, Anwar

    Available from UMI in association with The British Library. The distribution of ^ {75}Se in tissue equivalent materials was investigated employing Gamma ray Emission Topography with a rectilinear scanner utilizing NaI(Tl) and BGO detectors. The reconstructed images, using Filtered Back Projection and Iterative techniques were presented in 2D colour and 3D representations. Using a lead collimator of aperture 1.5 x 20 mm and 70 length, the distribution of selenium with variation of volume and concentration was examined and clearly seen. Several corrections such as background, scattering, attenuation compensation and X-ray characteristic suppression, were performed to improve the quality of the images which was evaluated in terms of the fidelity factor. The possibility of quantifying an image was considered with regard to spatial resolution and least detectable concentration. The spatial resolution was measured using two small vials containing the same concentration of selenium, the value obtained was the same as the width of the collimator aperture. The value of the least detectable concentration of selenium however, was difficult to find, due to the many ambiguous factors involved. The binding site of selenium which is based on quadrupole interaction with the surrounding electric field, was investigated employing Perturbed Angular Correlation (PAC) experiments using NaI(Tl) and BaF_2 detectors. Using NaI(Tl) detectors, it was difficult to observe the perturbation, due to the poor time resolution. The BaF_2 detector according to the literature has a shorter light emission decay time constant (0.6 ns), suggested that a better time resolution than that found with the NaI(Tl) detectors could be obtained. A Perturbed Angular Correlation experiment employing BaF _2 detectors and a fast-slow coincidence system was set up. The time differential PAC of selenium in solution showed an unperturbed angular correlation pattern. The main problem is the very short half life of the

  16. 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.

  17. 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.

  18. PacBio Sequencing and Its Applications

    PubMed Central

    Rhoads, Anthony; Au, Kin Fai

    2015-01-01

    Single-molecule, real-time sequencing developed by Pacific BioSciences offers longer read lengths than the second-generation sequencing (SGS) technologies, making it well-suited for unsolved problems in genome, transcriptome, and epigenetics research. The highly-contiguous de novo assemblies using PacBio sequencing can close gaps in current reference assemblies and characterize structural variation (SV) in personal genomes. With longer reads, we can sequence through extended repetitive regions and detect mutations, many of which are associated with diseases. Moreover, PacBio transcriptome sequencing is advantageous for the identification of gene isoforms and facilitates reliable discoveries of novel genes and novel isoforms of annotated genes, due to its ability to sequence full-length transcripts or fragments with significant lengths. Additionally, PacBio’s sequencing technique provides information that is useful for the direct detection of base modifications, such as methylation. In addition to using PacBio sequencing alone, many hybrid sequencing strategies have been developed to make use of more accurate short reads in conjunction with PacBio long reads. In general, hybrid sequencing strategies are more affordable and scalable especially for small-size laboratories than using PacBio Sequencing alone. The advent of PacBio sequencing has made available much information that could not be obtained via SGS alone. PMID:26542840

  19. 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.

  20. 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.

  1. Angular momentum

    NASA Astrophysics Data System (ADS)

    Shakur, Asif; Sinatra, Taylor

    2013-12-01

    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 the physics laboratory. Many traditional physics experiments can now be performed very conveniently in a pedagogically enlightening environment while simultaneously reducing the laboratory budget substantially by using student-owned smartphones.

  2. Preliminary results of a PACS implementation

    NASA Astrophysics Data System (ADS)

    Kishore, Sheel; Khalsa, Satjeet S.; Seshadri, Sridhar B.; Arenson, Ronald L.

    1991-07-01

    The Radiology Department at the University of Pennsylvania is in the process of clinically testing the first phase of its PACS implementation. The first phase has been designed to support two Intensive Care Units, two GE SIGNA MR units and a Du Pont FD 2000 Film Digitizer. The entire system has been running clinically for about three months. Any PACS effort involves integrating software and hardware from different manufactures. Some of the equipment on a PACS network are often 'closed' and provide limited access. In addition, the entire PACS system is expected to provide uninterrupted service, have adequate throughput and ensure data integrity. By and large, these goals have been met. Clinical testing has provided valuable insights about system integration and highlighted areas of improvement in the system design. A detailed discussion of these results is presented.

  3. Current developments in departmental PACS for ultrasound.

    PubMed

    Grenier, L E; Eng, P

    1995-01-01

    1. INTRODUCTION TO DEPARTMENTAL PACS. Full or partial Departmental PACS is generally taken to mean an image management system focused on serving the needs of a specific modality or modality application. It will provide a modality specific means of image acquisition, specialized redisplay of images, distribution, and local long term storage of images. A Departmental PACS can be considered in isolation or as a component in a distributed Radiology PACS which consists of one or more departmental work groups on a back bone, potentially with shared resources. 2. DEPARTMENTAL PACS Issues Implementation of a Departmental PACS requires an in-depth knowledge of departmental clinical practice and work flow in all affected areas in the department, including patient intake, image collection, data routing, retrieval of previous image data, reporting, and long term data management and storage. Optimization of modality specific image display systems requires significant involvement from representative physician users. System architectures and user interfaces must be flexible enough to support the span of variation in clinical practice encountered in the site. A departmental PACS should offer a variety of "open" communications interfaces, both local and wide area, recognizing that outreach efforts are often driven by specific imaging departments. Interfaces to other departmental PAC systems and other information systems must be considered in order to facilitate institutions developing "Best of Breed" PACS systems. As hospitals move toward the integrated electronic medical record, means need to exist for a client process launched from a physician desktop to acquire images and/or reports from a departmental system. At minimum, HIS/RIS interfaces need to be considered to minimize re-keying of data and reduce data entry errors. 3. DESIGN OBJECTIVES FOR ALI ULTRAPACS. The key objectives were to design a product which could function either as a free standing PACS or as a departmental

  4. 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

  5. Short history of PACS (Part II: Europe).

    PubMed

    Lemke, Heinz U

    2011-05-01

    Although the concept of picture archiving and communications systems (PACS) was developed in Europe during the latter part of the 1970s, no working system was completed at that time. The first PACS implementations took place in the United States in the early 1980s, e.g. at Pennsylvania University, UCLA, and Kansas City University. Some more or less successful PACS developments also took place in Europe in the 1980s, particularly in the Netherlands, Belgium, Austria, the United Kingdom, France, Italy, Scandinavia, and Germany. Most systems could be characterized by their focus on a single department, such as radiology or nuclear medicine. European hospital-wide PACS with high visibility evolved in the early 1990s in London (Hammersmith Hospital) and Vienna (SMZO). These were followed during the latter part of the 1990s by approximately 10-20 PACS installations in each of the major industrialized countries of Europe. Wide-area PACS covering several health care institutions in a region are now in the process of being implemented in a number of European countries. Because of limitations of space some countries, for example, Denmark, Finland, Spain, Greece, as well as Eastern European countries, etc. could not be appropriately represented in this paper. PMID:21466932

  6. Phonons with orbital angular momentum

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    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.

  7. 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.

  8. Topology and perturbation theory

    NASA Astrophysics Data System (ADS)

    Manjavidze, J.

    2000-08-01

    This paper contains description of the fields nonlinear modes successive quantization scheme. It is shown that the path integrals for absorption part of amplitudes are defined on the Dirac (δ-like) functional measure. This permits arbitrary transformation of the functional integral variables. New form of the perturbation theory achieved by mapping the quantum dynamics in the space WG of the (action, angle)-type collective variables. It is shown that the transformed perturbation theory contributions are accumulated exactly on the boundary ∂WG. Abilities of the developed formalism are illustrated by the Coulomb problem. This model is solved in the WC=(angle, angular momentum, Runge-Lentz vector) space and the reason of its exact integrability is emptiness of ∂WC.

  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. PMID:26942533

  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. PMID:16249838

  12. Reengineering the picture archiving and communication system (PACS) process for digital imaging networks PACS.

    PubMed

    Horton, M C; Lewis, T E; Kinsey, T V

    1999-05-01

    Prior to June 1997, military picture archiving and communications systems (PACS) were planned, procured, and installed with key decisions on the system, equipment, and even funding sources made through a research and development office called Medical Diagnostic Imaging Systems (MDIS). Beginning in June 1997, the Joint Imaging Technology Project Office (JITPO) initiated a collaborative and consultative process for planning and implementing PACS into military treatment facilities through a new Department of Defense (DoD) contract vehicle called digital imaging networks (DIN)-PACS. The JITPO reengineered this process incorporating multiple organizations and politics. The reengineered PACS process administered through the JITPO transformed the decision process and accountability from a single office to a consultative method that increased end-user knowledge, responsibility, and ownership in PACS. The JITPO continues to provide information and services that assist multiple groups and users in rendering PACS planning and implementation decisions. Local site project managers are involved from the outset and this end-user collaboration has made the sometimes difficult transition to PACS an easier and more acceptable process for all involved. Corporately, this process saved DoD sites millions by having PACS plans developed within the government and proposed to vendors second, and then having vendors respond specifically to those plans. The integrity and efficiency of the process have reduced the opportunity for implementing nonstandard systems while sharing resources and reducing wasted government dollars. This presentation will describe the chronology of changes, encountered obstacles, and lessons learned within the reengineering of the PACS process for DIN-PACS. PMID:10342167

  13. Digital neuroangiography: an innovative application of PACS

    NASA Astrophysics Data System (ADS)

    Hademenos, George J.; Valentino, Daniel J.; Close, Robert A.; Duckwiler, Gary R.; Vinuela, Fernando

    1994-05-01

    An important aspect of interventional neuroradiological procedures is the ability to access and interact with digital angiographic images to select and clinically evaluate intravascular therapeutic treatment. These issues can be adequately addressed and successfully accomplished using PACS. PACS provides the key technologies needed to access, display, and analyze sequential angiographic images. A dedicated neuroradiology PACS network consisting of workstations for the review of diagnostic data, quantitative analysis of arterial blood flow, and therapeutic assessment has been established at UCLA. The PACS provides not only a reliable and efficient infrastructure for on-line image retrieval and delivery of all digitally acquired angiographic images, but could also serve as a network supercomputing resource for computationally intensive calculations of hemodynamic parameters in the cerebral vasculature. In summary we have developed an innovative application of PACS in neuroangiography. It offers: (1) automatic optimized image display upon acquisition; (2) automatic retrieval of archived cases for a current patient; and, (3) a rapid, streamlined user interface for the quantitation of hemodynamic flow phenomena in normal and diseased cerebral vessels.

  14. The HERSCHEL/PACS early Data Products

    NASA Astrophysics Data System (ADS)

    Wieprecht, E.; Wetzstein, M.; Huygen, R.; Vandenbussche, B.; De Meester, W.

    2006-07-01

    ESA's Herschel Space Observatory to be launched in 2007, is the first space observatory covering the full far-infrared and submillimeter wavelength range (60 - 670 microns). The Photodetector Array Camera & Spectrometer (PACS) is one of the three science instruments. It contains two Ge:Ga photoconductor arrays and two bolometer arrays to perform imaging line spectroscopy and imaging photometry in the 60 - 210 micron wavelength band. The HERSCHEL ground segment (Herschel Common Science System - HCSS) is implemented using JAVA technology and written in a common effort by the HERSCHEL Science Center and the three instrument teams. The PACS Common Software System (PCSS) is based on the HCSS and used for the online and offline analysis of PACS data. For telemetry bandwidth reasons PACS science data are partially processed on board, compressed, cut into telemetry packets and transmitted to the ground. These steps are instrument mode dependent. We will present the software model which allows to reverse the discrete on board processing steps and evaluate the data. After decompression and reconstruction the detector data and instrument status information are organized in two main PACS Products. The design of these JAVA classes considers the individual sampling rates, data formats, memory and performance optimization aspects and comfortable user interfaces.

  15. The future of PACS in healthcare enterprises.

    PubMed

    Faggioni, Lorenzo; Neri, Emanuele; Castellana, Carlo; Caramella, Davide; Bartolozzi, Carlo

    2011-05-01

    Picture Archiving and Communication System (PACS), which was originally designed as a tool for facilitating radiologists in interpreting images more efficiently, is evolving into a hospital-integrated system storing diagnostic imaging information that often reaches far beyond Radiology. The continuous evolution of PACS technology has led to a gradual broadening of its applications, ranging from teleradiology to CAD (Computer-Assisted Diagnosis) and multidimensional imaging, and is moving into the direction of providing access to image data outside the Radiology department, so to reach all the branches of the healthcare enterprise. New perspectives have been created thanks to new technologies (such as holographic media and GRID computing) that are likely due to expand PACS-based applications even further, improving patient care and enhancing overall productivity. PMID:20634012

  16. A Layered Approach To Pacs Network Architecture

    NASA Astrophysics Data System (ADS)

    Hegde, Shankar S.; Prewitt, Judith M.

    1984-08-01

    Although the functions performed by the different nodes on the PACS network are many, it is possible to formulate a minimum set of service primitives such that the application software residing at the nodes can utilize those primitives to perform the functions. These primitives define the framework for the communication interface. The question of how these primitives fit into the concept of a layered network architecture is explored in this paper. The OSI model as applicable to the PACS network is described, the areas that need standardization are briefly mentioned, and the ongoing standardization efforts are addressed from the OSI perspective.

  17. PACS clinical experience at Georgetown University.

    PubMed

    Horii, S C; Mun, S K; Levine, B; Lo, B; Garra, B S; Zeman, R K; Freedman, M; Leftridge, C; Schellinger, D; Keyes, J

    1991-01-01

    Georgetown University Hospital has been operating an image management and communications system (IMACS or PACS) for three-and-a-half years. This work was initially funded under the Army Medical Research and Development Command Digital Imaging Network Systems (DINS) project. The system was taken from a research system supporting only radiology tasks to one extended to clinical use, and has been used in clinical work for two-and-a-half years. This paper will summarize our PACS clinical experience and will describe the operational features implemented and those still necessary. PMID:1913567

  18. 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.

  19. 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.

  20. Time-differential perturbed-angular-correlation and emission Moessbauer studies on {sup 99}Ru dispersed in YBa{sub 2}Cu{sub 3}O{sub 6.8} and YBa{sub 2}Cu{sub 3}O{sub 6}

    SciTech Connect

    Ohkubo, Y.; Kobayashi, Y.; Harasawa, K.; Ambe, S.; Okada, T.; Ambe, F.; Asai, K.; Shibata, S.

    1995-06-29

    The hyperfine interactions at {sup 99}Ru({sup $IMP@99}Rh) dispersed in YBa{sub 2}Cu{sub 3}O{sub 6.8} and YBa{sub 2}Cu{sub 3}O{sub 6} were studied by means of time-differential perturbed-angular-correlation (TDPAC) and emission Moessbauer spectroscopy. The TDPAC and Moessbauer measurements show that Ru ions are in the tetravalent state and exclusively occupy the Cu-1 sites, which form one-dimensional Cu-O chains in the orthorhombic phase. The oxygen coordinations around the Ru ions are discussed on the basis of the observed electric field gradients at {sup 99}Ru in YBa{sub 2}Cu{sub 3}O{sub 6.8} and YBa{sub 2}Cu{sub 3}O{sub 6}. 35 refs., 6 figs., 1 tab.

  1. 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.

  2. 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... and Individuals-Section 162 Assistance § 891.735 Notice upon PAC expiration. The PAC will provide that... will be required to pay as rent as a result of the expiration. The notice of expiration will...

  3. PERTURBING LIGNIFICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. Small PACS implementation using publicly available software

    NASA Astrophysics Data System (ADS)

    Passadore, Diego J.; Isoardi, Roberto A.; Gonzalez Nicolini, Federico J.; Ariza, P. P.; Novas, C. V.; Omati, S. A.

    1998-07-01

    Building cost effective PACS solutions is a main concern in developing countries. Hardware and software components are generally much more expensive than in developed countries and also more tightened financial constraints are the main reasons contributing to a slow rate of implementation of PACS. The extensive use of Internet for sharing resources and information has brought a broad number of freely available software packages to an ever-increasing number of users. In the field of medical imaging is possible to find image format conversion packages, DICOM compliant servers for all kinds of service classes, databases, web servers, image visualization, manipulation and analysis tools, etc. This paper describes a PACS implementation for review and storage built on freely available software. It currently integrates four diagnostic modalities (PET, CT, MR and NM), a Radiotherapy Treatment Planning workstation and several computers in a local area network, for image storage, database management and image review, processing and analysis. It also includes a web-based application that allows remote users to query the archive for studies from any workstation and to view the corresponding images and reports. We conclude that the advantage of using this approach is twofold. It allows a full understanding of all the issues involved in the implementation of a PACS and also contributes to keep costs down while enabling the development of a functional system for storage, distribution and review that can prove to be helpful for radiologists and referring physicians.

  5. PACS infrastructure supporting e-learning.

    PubMed

    Mildenberger, Peter; Brüggemann, Kerstin; Rösner, Freya; Koch, Katja; Ahlers, Christopher

    2011-05-01

    Digital imaging is becoming predominant in radiology. This has implications for teaching support, because conventional film-based concepts are now obsolete. The IHE Teaching File and Clinical Study Export (TCE) profile provides an excellent platform to enhance PACS infrastructure with educational functionality. This can be supplemented with dedicated e-learning tools. PMID:20619986

  6. Anatomy of an Extensible Open Source PACS.

    PubMed

    Valente, Frederico; Silva, Luís A Bastião; Godinho, Tiago Marques; Costa, Carlos

    2016-06-01

    The conception and deployment of cost effective Picture Archiving and Communication Systems (PACS) is a concern for small to medium medical imaging facilities, research environments, and developing countries' healthcare institutions. Financial constraints and the specificity of these scenarios contribute to a low adoption rate of PACS in those environments. Furthermore, with the advent of ubiquitous computing and new initiatives to improve healthcare information technologies and data sharing, such as IHE and XDS-i, a PACS must adapt quickly to changes. This paper describes Dicoogle, a software framework that enables developers and researchers to quickly prototype and deploy new functionality taking advantage of the embedded Digital Imaging and Communications in Medicine (DICOM) services. This full-fledged implementation of a PACS archive is very amenable to extension due to its plugin-based architecture and out-of-the-box functionality, which enables the exploration of large DICOM datasets and associated metadata. These characteristics make the proposed solution very interesting for prototyping, experimentation, and bridging functionality with deployed applications. Besides being an advanced mechanism for data discovery and retrieval based on DICOM object indexing, it enables the detection of inconsistencies in an institution's data and processes. Several use cases have benefited from this approach such as radiation dosage monitoring, Content-Based Image Retrieval (CBIR), and the use of the framework as support for classes targeting software engineering for clinical contexts. PMID:26497879

  7. [Designing and implementation of a PACS].

    PubMed

    Zhou, Hai-yan; Yao, Xing; Zhu, Yue-ming; Duan, Hui-long; Lu, Xu-dong; Zhao, Chen-hui

    2006-11-01

    PACS (Picture Archiving and Communication System) is successfully applied in Huzhou Central Hospital, and is well integrated with its HIS system by WEBSERVICE middleware. The system supports DICOM 3.0 Standard, and DICOM gateways are installed for modalities that do not support DICOM so as to have implemented the digitalization of all the image departments in the hospital. PMID:17300012

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Cosmological Perturbations

    NASA Astrophysics Data System (ADS)

    Lesgourges, J.

    2013-08-01

    We present a self-contained summary of the theory of linear cosmological perturbations. We emphasize the effect of the six parameters of the minimal cosmological model, first, on the spectrum of Cosmic Microwave Background temperature anisotropies, and second, on the linear matter power spectrum. We briefly review at the end the possible impact of a few non-minimal dark matter and dark energy models.

  13. Primordial power spectrum of tensor perturbations in Finsler spacetime

    NASA Astrophysics Data System (ADS)

    Li, Xin; Wang, Sai

    2016-02-01

    We first investigate the gravitational wave in the flat Finsler spacetime. In the Finslerian universe, we derive the perturbed gravitational field equation with tensor perturbations. The Finslerian background spacetime breaks rotational symmetry and induces parity violation. Then we obtain the modified primordial power spectrum of the tensor perturbations. The parity violation feature requires that the anisotropic effect contributes to the TT, TE, EE, BB angular correlation coefficients with l'=l+1 and TB, EB with l'=l. The numerical results show that the anisotropic contributions to the angular correlation coefficients depend on m, and TE and ET angular correlation coefficients are different.

  14. 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.

  15. 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. PMID:24744278

  16. Simulation And Communication Aspects Of PACS

    NASA Astrophysics Data System (ADS)

    Reijns, G. L.; Bakker, A. R.; de Valk, J. P. J.

    1988-06-01

    The storage of large amounts of digital image data and the communication of the images within a hospital are major problems in the development of a Picture Archiving and Communications System (PACS). Image compression reduces both the problems of storage capacity and of the image transmission rate by approximately a factor 12. It is shown that the use of memory buffers at different hierarchical system levels provides for an additional reduction in the required transmission rate. In order to determine the communication rates and number and size of the buffers, the PACS has been modelled by a system of queues and servers. Queueing models can be analysed by means of computer simulation but also mathematically. Examples of mathematical analysis are given and a simplified model of the department of radiology is evaluated.

  17. Pacs: Part Of An Integrated Communications System

    NASA Astrophysics Data System (ADS)

    Thompson, B. G.; Brenton, Bradley C.; Staab, Edward V.; Perry, J. Randolph; Parrish, Denise; Johnston, R. Eugene; Creasy, Jeffrey L.

    1985-09-01

    The Department of Radiology at the University of North Carolina-Chapel Hill (UNC) has developed the concept for an integrated picture archiving and communications system. A communications network has been installed, and computer facilities are being interfaced within radiology areas. Other projects include the establishment of a computer simulation model of departmental operations and assembly of a limited picture archival and communication system (PACS) beginning with the CT and NMR Modalities. While this approach may provide immediate clinical benefits, the initial thrust has been towards evaluation of prototype systems with flexibility for modifications. PACS operational parameters are being studied for their acceptability in support of radiology clinical services. The goal is to provide objective operational data as a basis for planning system improvements.

  18. 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

  19. The Medical Community's View On PACS

    NASA Astrophysics Data System (ADS)

    Glenn, William; Darlak, Joseph; Enzmann, Dieter R.; Gayler, Robert; James, A. Everette; Lehr, James L.; Newton, Carol; Partain, C. Leon; Zielonka, Jason S.; Marion, Joseph L.; Kouwenberg, Jef; Wake, Robert H.; Hindel, Robert; White, James M.

    1982-01-01

    Andre Duerinckx, PACS '82 Chairman. I think we can start with the second panel discussion, which will be the last activity of this conference. The Chairman of this Panel is Dr. Bill Glenn from Multi-Planar Diagnostic Imaging Inc. I want to say that what you are about to hear or say will be recorded, so please do use the microphones; don't say anything without using microphones. The same goes, of course, for the panel members.

  20. Impact Of Manual And Computer-Assisted PACS For Automated PACS

    NASA Astrophysics Data System (ADS)

    Lehr, James L.

    1983-05-01

    Considerations of totally electronic picture archiving system (PACS) often neglect the fact that every radiology practice currently has some system for storing and retrieving images and related alphanumeric data. Although these systems are usually manual, many departments now use on-line computers to help manage film flow. In either event, the creation of electronic PACS can be viewed as a classic data processing problem of automating an existing system, and the conversion should proceed through the usual steps of documenting the existing system in detail, and conducting feasibility studies and cost-benefit analyses. Documenting current systems should be facilitated by computer-assisted PACS - particularly documenting transaction volumes which can be provided as a by-product of radiology information management systems. Similarly cost-benefit analysis should be facilitated, although the cost/benefit ratio may be less favorable when comparing automated to computer-assisted PACS. Finally, information management features such as those provided by current on-line radiology systems provide a framework necessary to realize the full benefits of automated PACS.

  1. On-line performance characteristics of a radiology PACS

    NASA Astrophysics Data System (ADS)

    Wong, Albert W. K.; Loloyan, Mansur; Lou, Shyhliang A.; Huang, H. K.

    1992-07-01

    We have experienced that system reliability and performance become primary concerns when we moved our PACS from a research and development laboratory to a clinical environment. Providing consistent uptime builds user confidence and fast service accelerates system acceptance. The fault-tolerant mechanism implemented in our PACS has minimized system downtime. This paper considers the performance issues of an on-line multimodal PACS. The intent of conducting performance measurements on individual PACS components such as the radiological imaging devices, archive devices, host computers, and communication networks is to compare the throughput rates of these components in a real-time clinical environment as a basis of evaluating the overall throughput of a PACS system. Our primary goal is to identify the major factors that degrade the performance of a PACS, and to establish new strategies so that fast service with minimal delay is provided to the clinic. Approximately 200-Gbyte data transactions including CT, MR and CR images from our PACS were analyzed. Results showed that PACS throughput was limited by two major factors: (1) low-speed data interface used in the radiological imaging devices and archive devices; (2) network degradation due to heavy network traffic. We concluded that PACS throughput could be improved by well- designed network architecture and image-routing strategy. However, device-dependent low- speed data interface limited PACS performance.

  2. Multiple communication networks for a radiological PACS

    NASA Astrophysics Data System (ADS)

    Wong, Albert W. K.; Stewart, Brent K.; Lou, Shyhliang A.; Chan, Kelby K.; Huang, H. K.

    1991-07-01

    The authors have implemented a communication network connecting multiple buildings for their picture archiving and communication system (PACS) in the Radiology Department at UCLA. The network consists of three types of local area networks (LANs) and a 1.0-km fiber-optic link connecting the outpatient and inpatient facilities. Images from radiologic imaging devices (4 CT scanners, 5 MR scanners, 4 CR units and 5 film digitizers) are transmitted to the acquisition computers via the Ethernet LAN. The fiber distributed data interface (FDDI) LAN then provides data communication among the cluster controllers, the acquisition computers, and the database servers. A 1-gigabit UltraNet LAN is used to route images from the cluster controllers to remote display workstations. All inter-building connections are through fiber-optic cables. Among these multiple networks, Ethernet offers multi-access to the multimodal PACS in image acquisition, FDDI controls a fast data flow so that all acquired images have a shorter residence time on local disks, and UltraNet provides high-speed transfer of images from the cluster controllers to the display workstations. The three-tiered functionality of Ethernet, FDDI, and UltraNet eliminates network traffic bottlenecks and hence provides high performance in image communication. The delay time of a 2K X 2K X 8-bit CR image (4 MBytes) from acquisition to display is less than 5 minutes. In addition, the standard Ethernet serves as a backup to guarantee network connectivity of the entire PACS.

  3. The HERSCHEL/PACS Spectrometer Pipeline

    NASA Astrophysics Data System (ADS)

    Schreiber, J.; Wieprecht, E.; de Jong, J.; Wetzstein, M.; Jacobson, J.; Huygen, R.; Appleton, P.; Bouwman, J.; Contursi, A.; Fadda, D.; Jean, C.; Klaas, U.; Royer, P.; Vandenbussche, B.

    2009-09-01

    ESA's Herschel Space Observatory, to be launched in 2009, is the first space observatory covering the full far-infrared and sub-millimeter wavelength range (60 - 670 micron). The Photodetector Array Camera & Spectrometer (PACS) is one of the three science instruments. It employs two Ge:Ga photoconductor arrays and two bolometer arrays to perform integral field spectroscopy and imaging photometry in the 60 - 210 micron wavelength band. The interactive PACS Spectrometer and Photometer \\citep{wieprecht09} Data Reduction Pipeline is integrated in the Herschel Data Processing System. The DP is implemented using Java technology and written in a common effort by the HERSCHEL Science Center (HSC) and the three instrument teams. We overview the concept and status of the PACS Spectrometer Data Reduction Pipeline. Additionally, we address the instrument mode-dependent data processing and the definition of the products of the different processing levels. Finally, we show first results by applying the pipeline on flight model instrument level test data.

  4. Deep Herschel PACS point spread functions

    NASA Astrophysics Data System (ADS)

    Bocchio, M.; Bianchi, S.; Abergel, A.

    2016-06-01

    The knowledge of the point spread function (PSF) of imaging instruments represents a fundamental requirement for astronomical observations. The Herschel PACS PSFs delivered by the instrument control centre are obtained from observations of the Vesta asteroid, which provides a characterisation of the central part and, therefore, excludes fainter features. In many cases, however, information on both the core and wings of the PSFs is needed. With this aim, we combine Vesta and Mars dedicated observations and obtain PACS PSFs with an unprecedented dynamic range (~106) at slow and fast scan speeds for the three photometric bands. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.FITS files of our PACS PSFs (Fig. 2) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A117

  5. Data protection and security issues of PACS

    NASA Astrophysics Data System (ADS)

    Bakker, Albert R.

    1992-07-01

    It is observed that the dataprotection aspects of PACS have hardly been explored, while for Hospital Information Systems (HIS) considerable attention has been paid to these aspects. In the dataprotection domain around HIS we distinguish the aspects data integrity (safety), usage integrity (confidentiality, privacy) and availability. A wide range of measures (dealing with hardware, software or organization/procedures) has been suggested to achieve adequate protection. For each system a selection of the suggested measures has to be made, where risk is balanced against costs. It seems that it is taken for granted that the usual measures as implemented for HIS will also be adequate for PACS. In this paper dataprotection aspects for PACS are discussed. Apart from similarities with the HIS situation also differences will be identified. In particular safeguarding the image databank requires special measured. Dataprotection should not be an add-on of the system, it should be taken into account in the design phase. As an illustration two alternatives for the organization of the image databank will be considered from the point of view of dataprotection. The one being consecutive historical storage of images, the other the clustering of images of the same patient on the same volume in the storage system.

  6. 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.

  7. Design of a PACS cluster controller

    NASA Astrophysics Data System (ADS)

    Taira, Ricky K.; Wong, Albert W. K.; Stewart, Brent K.; Huang, H. K.

    1992-07-01

    Our PACS design consists of clusters of computerized devices. At the center of each cluster is an intelligent machine termed a cluster controller. A cluster controller performs the following tasks: (1) receives images from capture computers, (2) extracts descriptive text information describing the received studies, (3) updates a network-accessible database management system, (4) determines the destination workstations to forward the newly generated studies, (5) automatically retrieves necessary comparison images from a distributed optical archive, (6) automatically corrects the orientation of computed radiography images, (7) archives new studies onto optical disk, (8) deletes images stored on remote capture computers upon successful image archival, and (9) services archive retrieval requests from remote workstations and other cluster controllers. The cluster controller is the only class of PACS computers that must communicate with all other types of PACS nodes (acquisition, other cluster controllers, radiologist''s workstation, referring physician''s workstation, printing stations, and database servers). This paper presents details of the logical partitioning of computers into clusters and the central role of the cluster controller machines in image acquisition, image routing, optical archive management, and system reliability.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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. PMID:27318162

  15. 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

  16. Perturbative fragmentation

    SciTech Connect

    Kopeliovich, B. Z.; Pirner, H.-J.; Potashnikova, I. K.; Schmidt, Ivan; Tarasov, A. V.

    2008-03-01

    The Berger model of perturbative fragmentation of quarks to pions is improved by providing an absolute normalization and keeping all terms in a (1-z) expansion, which makes the calculation valid at all values of fractional pion momentum z. We also replace the nonrelativistic wave function of a loosely bound pion by the more realistic procedure of projecting to the light-cone pion wave function, which in turn is taken from well known models. The full calculation does not confirm the (1-z){sup 2} behavior of the fragmentation function (FF) predicted in [E. L. Berger, Z. Phys. C 4, 289 (1980); Phys. Lett. 89B, 241 (1980] for z>0.5, and only works at very large z>0.95, where it is in reasonable agreement with phenomenological FFs. Otherwise, we observe quite a different z-dependence which grossly underestimates data at smaller z. The disagreement is reduced after the addition of pions from decays of light vector mesons, but still remains considerable. The process dependent higher twist terms are also calculated exactly and found to be important at large z and/or p{sub T}.

  17. 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.

  18. Phenomenological Determination of the Orbital Angular Momentum

    SciTech Connect

    Ramsey, Gordon P.

    2009-08-04

    Measurements involving the gluon spin, {delta}G(x, t) and the corresponding asymmetry, A(x,t) = {delta}G(x,t)/G(x,t) play an important role in quantitative understanding of proton structure. We have modeled the asymmetry perturbatively and calculated model corrections to obtain information about non-perturbative spin-orbit effects. These models are consistent with existing COMPASS and HERMES data on the gluon asymmetry. The J{sub z} = (1/2) sum rule is used to generate values of orbital angular momentum at LO and NLO. For models consistent with data, the orbital angular momentum is small. Our studies specify accuracy that future measurements should achieve to constrain theoretical models for nucleon structure.

  19. 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.

  20. Hadronic Structure from Perturbative Dressing

    NASA Astrophysics Data System (ADS)

    Arash, Firooz

    2005-09-01

    Perturbative dressing of a valence quark in QCD produces the internal structure of an extended object, the so-called Valon. The valon structure is universal and independent of the hosting hadron. Polarized and unpolarized proton and pion structure functions are calculated in the valon representation. One finds that although all the available data on g1p,n,d are easily reproduced, a sizable orbital angular momentum associated with the partonic structure of the valon is required in order to have a spin 1/2 valon.

  1. 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,…

  2. 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.

  3. Integration Of An MR Image Network Into A Clinical PACS

    NASA Astrophysics Data System (ADS)

    Ratib, Osman M.; Mankovich, Nicholas J.; Taira, Ricky K.; Cho, Paul S.; Huang, H. K.

    1988-06-01

    A direct link between a clinical pediatric PACS module and a FONAR MRI image network was implemented. The original MR network combines together the MR scanner, a remote viewing station and a central archiving station. The pediatric PACS directly connects to the archiving unit through an Ethernet TCP-IP network adhering to FONAR's protocol. The PACS communication software developed supports the transfer of patient studies and the patient information directly from the MR archive database to the pediatric PACS. In the first phase of our project we developed a package to transfer data between a VAX-111750 and the IBM PC I AT-based MR archive database through the Ethernet network. This system served as a model for PACS-to-modality network communication. Once testing was complete on this research network, the software and network hardware was moved to the clinical pediatric VAX for full PACS integration. In parallel to the direct transmission of digital images to the Pediatric PACS, a broadband communication system in video format was developed for real-time broadcasting of images originating from the MR console to 8 remote viewing stations distributed in the radiology department. These analog viewing stations allow the radiologists to directly monitor patient positioning and to select the scan levels during a patient examination from remote locations in the radiology department. This paper reports (1) the technical details of this implementation, (2) the merits of this network development scheme, and (3) the performance statistics of the network-to-PACS interface.

  4. 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.

  5. PC reporting system for radiologists: practical use under PACS environment.

    PubMed

    Nakata, N; Yoshihiro, S; Miida, K; Tashima, M; Sunakawa, Y; Harada, J; Tada, S; Fukuda, K

    2001-07-01

    To evaluate the practical usefulness of several types of the reporting system especially for radiologists, we have developed and employed several reporting systems. We categorized those reporting systems as follows (1) stand alone PC reporting system; (2) linked reporting system with PACS environment; (3) integrated three-dimensional (3D) imaging workstation (WS) with the intranet. We have evaluated the advantages and disadvantages of those three systems, and compared between the reporting system without PACS and network reporting system with PACS. Using linked reporting system with PACS, radiologists could easily reference both previous reports and archived diagnostic images, and also make their teaching files quickly. In conclusion, the reporting system under PACS environment is found to be practical and helpful for Japanese radiologists. PMID:11378217

  6. Detailed description of the Mayo/IBM PACS

    NASA Astrophysics Data System (ADS)

    Gehring, Dale G.; Persons, Kenneth R.; Rothman, Melvyn L.; Salutz, James R.; Morin, Richard L.

    1991-07-01

    The Mayo Clinic and IBM/Rochester have jointly developed a picture archiving system (PACS) for use with Mayo's MRI and Neuro-CT imaging modalities. The system was developed to replace the imaging system's vendor-supplied magnetic tape archiving capability. The system consists of seven MR imagers and nine CT scanners, each interfaced to the PACS via IBM Personal System/2(tm) (PS/2) computers, which act as gateways from the imaging modality to the PACS network. The PAC system operates on the token-ring component of Mayo's city-wide local area network. Also on the PACS network are four optical storage subsystems used for image archival, three optical subsystems used for image retrieval, an IBM Application System/400(tm) (AS/400) computer used for database management and multiple PS/2-based image display systems and their image servers.

  7. Partonic orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Arash, Firooz; Taghavi-Shahri, Fatemeh; Shahveh, Abolfazl

    2013-04-01

    Ji's decomposition of nucleon spin is used and the orbital angular momentum of quarks and gluon are calculated. We have utilized the so called valon model description of the nucleon in the next to leading order. It is found that the average orbital angular momentum of quarks is positive, but small, whereas that of gluon is negative and large. Individual quark flavor contributions are also calculated. Some regularities on the total angular momentum of the quarks and gluon are observed.

  8. 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.

  9. 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. PMID:24412856

  10. A Comparative Time Differential Perturbed Angular Correlation Study of the Nuclear Quadrupole Interaction in HfF4·HF·2H2O Using 180mHf and 181Hf(β-)181Ta as Nuclear Probes: Is Ta an Innocent Spy?

    NASA Astrophysics Data System (ADS)

    Butz, Tilman; Das, Satyendra K.; Manzhur, Yurij

    2009-02-01

    We report on a comparative study of the nuclear quadrupole interaction of the nuclear probes 180mHf and 181Hf(β -)181Ta in HfF4・HF・2H2O using time differential perturbed angular correlations (TDPAC) at 300 K. For the first probe, assuming a Lorentzian frequency distribution, we obtained ωQ= 103(4) Mrad/s, an asymmetry parameter η = 0.68(3), a linewidth δ = 7.3(3.9)%, and full anisotropy within experimental accuracy. For the second probe, assuming a Lorentzian frequency distribution, we obtained three fractions: (1) with 56.5(7)%, ωQ= 126.64(4) Mrad/s and η = 0.9241(4) with a rather small distribution δ = 0.40(8)% which is attributed to HfF4・HF・2H2O; (2) with 4.6(4)%, ωQ = 161.7(3) Mrad/s and η = 0.761(4) assuming no line broadening which is tentatively attributed to a small admixture of Hf2OF6・H2O; (3) the remainder of 39.0(7)% accounts for a rapid loss of anisotropy and is modelled by a perturbation function with a sharp frequency multiplied by an exponential factor exp(-λ t) with λ = 0.55(2) ns-1. Whereas the small admixture of Hf2OF6・H2O escapes detection by the 180mHf probe, there is no rapid loss of roughly half the anisotropy as is the case with 181Hf(β -)181Ta. This loss could in principle be due to fluctuating electric field gradients originating from movements of nearest neighbour HF adducts and/or H2O molecules after nuclear transmutation to the foreign atom Ta which are absent for the isomeric probe. Alternatively, paramagnetic Ta ions could lead to fluctuating magnetic dipole fields which, when combined with fluctuating electric field gradients, could also lead to a rapid loss of anisotropy. In any case, Ta is not an "innocent spy" in this compound. Although 180mHf is not a convenient probe for conventional spectrometers, the use of fast digitizers and software coincidences would allow to use all γ -quanta in the stretched cascade which would greatly improve the efficiency of the spectrometer. 180mHf could also serve as a Pu

  11. Impact of volumetric ultrasound on PACS

    NASA Astrophysics Data System (ADS)

    Horii, Steven; Goldszal, Alberto; Redfern, Regina; Coleman, Beverly; Langer, Jill; Morton, Dan; Rowling, Susan; Boonn, William; Iyoob, Christopher

    2006-03-01

    The purpose of this study was to determine if the size of ultrasound examinations was increasing over time. The primary reasons for this are believed to be an increased number of images per study, the incorporation of "cine loops", and increased use of color flow Doppler. The result of this study, if it supports the hypothesis that ultrasound study size is increasing, would be directly applicable to planning for future expansion of storage in the Ultrasound PACS. Data were obtained from the ultrasound PACS server for number of studies, number of images, and total stored volume for sampled months (January and July of 2003 - 2006). The investigators believed that these months would provide a reasonable sample of study size as examination types did not vary significantly from month to month (based on Departmental statistics). The Radiology Department's information system (RIS) was used to determine total yearly ultrasound examination volume to determine the trend over time. Because no protected health information (PHI) was to be used in this study, the investigators believed that no IRB approval was necessary. The number of studies done per month was more variable than the investigators had believed. One month in particular (July, 2003) had an anomalously large number of studies. However, despite this, computations of the number of images per study, the total data volume per study, and the average amount of data per image did show an increasing trend as expected. Also, the total volume of data stored showed an increasing trend over the study time period. The investigators' hypothesis that examination size is increasing has been demonstrated to be true for the months sampled. From Departmental data, the investigators know that the most recent ultrasound yearly volume increased approximately ten percent over the previous year, and that trend was also seen for the study period (from 7-10 percent per year increase in volume). With the information that the examination size

  12. The pH-Responsive PacC Transcription Factor of Aspergillus fumigatus Governs Epithelial Entry and Tissue Invasion during Pulmonary Aspergillosis

    PubMed Central

    Alcazar-Fuoli, Laura; Cairns, Timothy C.; Muñoz, Alberto; Walker, Louise A.; Herbst, Susanne; Safari, Maryam; Cheverton, Angela M.; Chen, Dan; Liu, Hong; Saijo, Shinobu; Fedorova, Natalie D.; Armstrong-James, Darius; Munro, Carol A.; Read, Nick D.; Filler, Scott G.; Espeso, Eduardo A.; Nierman, William C.; Haas, Hubertus; Bignell, Elaine M.

    2014-01-01

    Destruction of the pulmonary epithelium is a major feature of lung diseases caused by the mould pathogen Aspergillus fumigatus. Although it is widely postulated that tissue invasion is governed by fungal proteases, A. fumigatus mutants lacking individual or multiple enzymes remain fully invasive, suggesting a concomitant requirement for other pathogenic activities during host invasion. In this study we discovered, and exploited, a novel, tissue non-invasive, phenotype in A. fumigatus mutants lacking the pH-responsive transcription factor PacC. Our study revealed a novel mode of epithelial entry, occurring in a cell wall-dependent manner prior to protease production, and via the Dectin-1 β-glucan receptor. ΔpacC mutants are defective in both contact-mediated epithelial entry and protease expression, and significantly attenuated for pathogenicity in leukopenic mice. We combined murine infection modelling, in vivo transcriptomics, and in vitro infections of human alveolar epithelia, to delineate two major, and sequentially acting, PacC-dependent processes impacting epithelial integrity in vitro and tissue invasion in the whole animal. We demonstrate that A. fumigatus spores and germlings are internalised by epithelial cells in a contact-, actin-, cell wall- and Dectin-1 dependent manner and ΔpacC mutants, which aberrantly remodel the cell wall during germinative growth, are unable to gain entry into epithelial cells, both in vitro and in vivo. We further show that PacC acts as a global transcriptional regulator of secreted molecules during growth in the leukopenic mammalian lung, and profile the full cohort of secreted gene products expressed during invasive infection. Our study reveals a combinatorial mode of tissue entry dependent upon sequential, and mechanistically distinct, perturbations of the pulmonary epithelium and demonstrates, for the first time a protective role for Dectin-1 blockade in epithelial defences. Infecting ΔpacC mutants are hypersensitive to

  13. 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.

  14. Pituitary Adenylate Cyclase-activating Polypeptide (PACAP)/PAC1HOP1 Receptor Activation Coordinates Multiple Neurotrophic Signaling Pathways

    PubMed Central

    May, Victor; Lutz, Eve; MacKenzie, Christopher; Schutz, Kristin C.; Dozark, Kate; Braas, Karen M.

    2010-01-01

    MAPK and Akt pathways are predominant mediators of trophic signaling for many neuronal systems. Among the vasoactive intestinal peptide/secretin/glucagon family of related peptides, pituitary adenylate cyclase-activating polypeptide (PACAP) binding to specific PAC1 receptor isoforms can engage multiple signaling pathways and promote neuroprotection through mechanisms that are not well understood. Using a primary sympathetic neuronal system, the current studies demonstrate that PACAP activation of PAC1HOP1 receptors engages both MAPK and Akt neurotrophic pathways in an integrated program to facilitate neuronal survival after growth factor withdrawal. PACAP not only stimulated prosurvival ERK1/2 and ERK5 activation but also abrogated SAPK/JNK and p38 MAPK signaling in parallel. In contrast to the potent and rapid effects of PACAP in ERK1/2 phosphorylation, PACAP stimulated Akt phosphorylation in a late phase of PAC1HOP1 receptor signaling. From inhibitor and immunoprecipitation analyses, the PACAP/PAC1HOP1 receptor-mediated Akt responses did not represent transactivation mechanisms but appeared to depend on Gαq/phosphatidylinositol 3-kinase γ activity and vesicular internalization pathways. Phosphatidylinositol 3-kinase γ-selective inhibitors blocked PACAP-stimulated Akt phosphorylation in primary neuronal cultures and in PAC1HOP1-overexpressing cell lines; RNA interference-mediated knockdown of the receptor effectors attenuated PACAP-mediated Akt activation. Similarly, perturbation of endocytic pathways also blocked Akt phosphorylation. Between ERK and Akt pathways, PACAP-stimulated Akt signaling was the primary cascade that attenuated cultured neuron apoptosis after growth factor withdrawal. The partitioning of PACAP-mediated Akt signaling in endosomes may be a key mechanism contributing to the high spatial and temporal specificity in signal transduction necessary for survival pathways. PMID:20093365

  15. Angular Acceleration Without Torque?

    NASA Astrophysics Data System (ADS)

    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.2

  16. 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.

  17. Novel class of highly selective divanillin-based PACs

    NASA Astrophysics Data System (ADS)

    Medina, Arturo N.; Ferreira, Lawrence; Tadros, Sobhy P.; Sizensky, Joseph J.; Fregeolle, M.; Blakeney, Andrew J.; Toukhy, Medhat A.

    1996-06-01

    A new class of diazonaphthoquinone (DNQ) photoactive compounds (PACs) based on the divanillin core is introduced in this paper. The general structure of these PAC backbones is shown in Formula 1. The divanillin structure possesses unique electronic characteristics which influence its DNQ-SO2Cl esterification reactions to be highly selective. The most reactive site for esterification in Formula 1 is one of the divanillin hydroxyls despite the typically higher steric hindrance. Surprisingly, the esterification product is then significantly deactivated towards esterification at the other previously equivalent divanillin OH. The result of using 3 equivalents of DNQ-SO2Cl to esterify tetraphenolic species is the formation of high percentages of the specific triester in which the second divanillyl OH remains unesterified. The deactivation of the second divanillin OH after the initial esterification indicates some interaction between the two o,o-biphenol rings despite its inability to be coplanar for conjugation of (pi) electrons because of steric hindrance. Possible explanations for this interaction are explored using molecular simulation tools. Diverse members of the divanillin PAC family have been prepared from phenols of varying structure and hydrophobicities. These PACs were tested lithographically and the results correlated with PAC backbone structure. The characteristic dissolution rate behavior of the resist formulations based on triesterified PACs, measured as a function of exposure dose, generally show high discrimination and strong inhibition, even with the more hydrophilic PACs. These formulations typically exhibited high resolution, wide focus latitude, and exposure margins greater than 2.0 in lithographic screening.

  18. Centralized vs. Distributed PACS for Intensive Care Units

    NASA Astrophysics Data System (ADS)

    Cho, Paul S.; Huang, H. K.; Tillisch, Jan

    1989-05-01

    One clinical environment which can immediately benefit from the implementation of a radiologic PACS is the intensive care unit (ICU). Our previous study has demonstrated the feasibility and timeliness of routine image transmission to an ICU. In anticipation of future expansion of this service, we have investigated two different models for a hospital-wide ICU PACS. These models included a centralized and a distributed processing PACS configuration. Their comparison indicated that although the distributed model offers some major advantages over the centralized model, the latter may hold a rightful place in the inter-departmental service, especially if the cost issue is a critical factor.

  19. 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.

  20. 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.

  1. Radiology information system control of a DICOM-based PACS

    NASA Astrophysics Data System (ADS)

    Behlen, Fred M.; Montner, Steven M.; Hoffmann, Kenneth R.; MacMahon, Heber; Weldy, James B.; Sayre, Richard E.

    1997-05-01

    PACS implementations require IS data for efficient operation and coherent information management. The images contributing to a radiology report in a practical multi-vendor PACS implementation may be derived from more than one DICOM study, and it is the Radiology Information System (RIS) that is responsible for the report. Flows of existing RIS-based information were studied and the required set of messages between the PACS archive and the RIS was defined. An archive providing the required functionality using standard and extended DICOM protocols was specified and acquired. The DICOM interface for the RIS was developed in-house using the M(MUMPS) programming language native to the RIS. We found that close integration of a RIS and PACS can be provided using DICOM protocols employing extensions compatible with the standard. The DICOM interfaces for textural data can be implemented in a MUMPS-based RIS without the need for an external interface 'box'.

  2. Product Related Advantages of a Structured PACS Architecture

    PubMed Central

    Greinacher, C.F.C.; Fuchs, D.; Perry, J.

    1986-01-01

    Most of the previously described PACS solutions are either developed and evaluated by the users themselves or they are pilot projects evaluated in close cooperation between a user and one or several manufacturers. Many of the prerequisites that will have to be met by future PACS are of minor interest in these pilot projects; e.g. minimization of costs, compatibility between different manufacturers' equipment, feasibility of systems engineering and customizing of a standard product, serviceability of different manufacturers' subsystems, stepwise introduction of the system into the daily routine and failsafety of the system. The paper shows a structured PACS architecture as a prerequisite to make PACS a high quality system from the user's point of view.

  3. Transient dynamics of perturbations in astrophysical disks

    NASA Astrophysics Data System (ADS)

    Razdoburdin, D. N.; Zhuravlev, V. V.

    2015-11-01

    We review some aspects of a major unsolved problem in understanding astrophysical (in particular, accretion) disks: whether the disk interiors can be effectively viscous in spite of the absence of magnetorotational instability. A rotational homogeneous inviscid flow with a Keplerian angular velocity profile is spectrally stable, making the transient growth of perturbations a candidate mechanism for energy transfer from regular motion to perturbations. Transient perturbations differ qualitatively from perturbation modes and can grow substantially in shear flows due to the nonnormality of their dynamical evolution operator. Because the eigenvectors of this operator, also known as perturbation modes, are not pairwise orthogonal, they can mutually interfere, resulting in the transient growth of their linear combinations. Physically, a growing transient perturbation is a leading spiral whose branches are shrunk as a result of the differential rotation of the flow. We discuss in detail the transient growth of vortex shearing harmonics in the spatially local limit, as well as methods for identifying the optimal (fastest growth) perturbations. Special attention is given to obtaining such solutions variationally by integrating the respective direct and adjoint equations forward and backward in time. The presentation is intended for experts new to the subject.

  4. 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.

  5. Why PACS is no longer a four-letter word.

    PubMed

    Chopra, R M

    2000-01-01

    The real value of PACS is not realized until widespread adoption exists among physicians other than interpreting radiologists. Referring physicians at the office level, in the operating room and in other departments must be willing to embrace the reading of images on monitors. That takes time. The payoff for a PACS system is therefore not realized until sometime in the future. Given the huge up-front capital expenditure required of PACS solutions, it is no wonder that the decision has historically been a difficult one to make. Enter the application service provider (ASP). The marriage of the ASP model to PACS seems to be one of the true "killer apps" currently available in the healthcare technology space. An ASP can host and maintain the software inherent in PACS solutions. Images are centrally archived over the short-, medium-, and long-term timeframe, utilizing state-of-art data management facilities. Some ASPs also provide the necessary bandwidth to office sites and the small amount of hardware that is required onsite, such as viewing stations or monitors. Costs for Internet-based image management under the ASP model rely on a pay-as-you-go formula, which may include all software, support, required hardware and bandwidth as part of the service. There may be a minor up-front fee for installation. The ASP pricing model eliminates the huge gamble an organization takes on "big iron" PACS purchases. Those benefits rely on the first rule of finance: a dollar today is worth more than a dollar tomorrow. PACS and ASPs were made for one another. Because the financial benefits of PACS are realized over time, the timing of cash flows is extremely important. Other benefits inherent in the ASP model such as scalability, diminished need for IT personnel, software version integrity and better pricing because of economies of scale are attractive also. PMID:11151321

  6. 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.

  7. 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.

  8. Hyperfine Magnetic Field Measurements in the Heusler Alloys COBALT(2)-TITANIUM-Z, COBALT(2)-MAGNESIUM-Z (z = Silicon, Germanium, and Tin) and COBALT(2)-MAGNESIUM- Gallium Using the Moessbauer Effect (me) and the Time Differential Perturbed Angular Correlation (tdpac) Techniques

    NASA Astrophysics Data System (ADS)

    Lahamer, Amer Said

    1990-01-01

    Measurements of the hyperfine magnetic field in a series of Heusler alloys were performed. The probes were in (^{119}Sn) and cadmium (^{111}Cd). These measurements were performed at the University of Cincinnati in Cincinnati, Ohio. Two techniques were used. The first technique was the Mossbauer effect, which was used to measure the hyperfine magnetic field on ^{119 }Sn in Co_2TiZ (Z = Si, Ge, and Sn), and the second technique was the Time Differential Perturbed Angular Correlation which was used to measure the hyperfine magnetic field on ^ {111}Cd in the Co_2MnZ (Z = Si, Ge, Sn, and Ga). The probes are expected to go to the Z sites of the alloys. The hyperfine magnetic field measurements on ^{119}Sn in Co _2TiZ (Z = Si, Ge, and Sn) alloys were done at room, dry ice and liquid nitrogen temperatures by using the Mossbauer effect technique. The data were fitted by using a least squares fit from which three parameters were extracted. These parameters are the isomer shift, the quadrupole splitting and the hyperfine magnetic field. Temperature variation measurements of the hyperfine magnetic field were performed on ^{111 }Cd in Co_2MnZ (Z = Si, Ge, Sn, and Ga) alloys. The data were fitted again by using a least squares fit from which the Larmor frequency which is related to the hyperfine magnetic field was extracted. Also the Fourier Transforms were taken of the data, on the one hand to confirm the results of the least squares fit and on the other hand to look for more frequencies. Results of the Fourier Transforms show that some of the probe, ^{111}In, did go to the Co site in the Co_2MnZ (Z = Ga, Si, and Ge) alloys. The hmf on ^{111 }Cd in the Co site of these alloys is found to be 68 kOe which is consistent with the value found in the literature. Two theoretical models were examined for the trends of hyperfine magnetic field on ^{119 }Sn and ^{111}Cd in Co_2MnZ (Z = Si, Ge, Sn, and Ga) alloys. These are the Campbell and Blandin model and the Stearns' overlap model

  9. 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

  10. 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).

  11. Do cosmological perturbations have zero mean?

    SciTech Connect

    Armendariz-Picon, Cristian

    2011-03-01

    A central assumption in our analysis of cosmic structure is that cosmological perturbations have a constant ensemble mean, which can be set to zero by appropriate choice of the background. This property is one of the consequences of statistical homogeneity, the invariance of correlation functions under spatial translations. In this article we explore whether cosmological perturbations indeed have zero mean, and thus test one aspect of statistical homogeneity. We carry out a classical test of the zero mean hypothesis against a class of alternatives in which primordial perturbations have inhomogeneous non-vanishing means, but homogeneous and isotropic covariances. Apart from Gaussianity, our test does not make any additional assumptions about the nature of the perturbations and is thus rather generic and model-independent. The test statistic we employ is essentially Student's t statistic, applied to appropriately masked, foreground-cleaned cosmic microwave background anisotropy maps produced by the WMAP mission. We find evidence for a non-zero mean in a particular range of multipoles, but the evidence against the zero mean hypothesis goes away when we correct for multiple testing. We also place constraints on the mean of the temperature multipoles as a function of angular scale. On angular scales smaller than four degrees, a non-zero mean has to be at least an order of magnitude smaller than the standard deviation of the temperature anisotropies.

  12. Metamaterial broadband angular selectivity

    NASA Astrophysics Data System (ADS)

    Shen, Yichen; Ye, Dexin; Wang, Li; Celanovic, Ivan; Ran, Lixin; Joannopoulos, John D.; Soljačić, Marin

    2014-09-01

    We demonstrate how broadband angular selectivity can be achieved with stacks of one-dimensionally periodic photonic crystals, each consisting of alternating isotropic layers and effective anisotropic layers, where each effective anisotropic layer is constructed from a multilayered metamaterial. We show that by simply changing the structure of the metamaterials, the selective angle can be tuned to a broad range of angles; and, by increasing the number of stacks, the angular transmission window can be made as narrow as desired. As a proof of principle, we realize the idea experimentally in the microwave regime. The angular selectivity and tunability we report here can have various applications such as in directional control of electromagnetic emitters and detectors.

  13. 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.

  14. 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.

  15. 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.

  16. PACS project management utilizing web-based tools

    NASA Astrophysics Data System (ADS)

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

    2000-05-01

    As Picture Archiving and Communications Systems (PACS) implementations become more widespread, the management of deploying large, multi-facility PACS will become a more frequent occurrence. The tools and usability of the World Wide Web to disseminate project management information obviates time, distance, participant availability, and data format constraints, allowing for the effective collection and dissemination of PACS planning, implementation information, for a potentially limitless number of concurrent PACS sites. This paper will speak to tools, such as (1) a topic specific discussion board, (2) a 'restricted' Intranet, within a 'project' Intranet. We will also discuss project specific methods currently in use in a leading edge, regional PACS implementation concerning the sharing of project schedules, physical drawings, images of implementations, site-specific data, point of contacts lists, project milestones, and a general project overview. The individual benefits realized for the end user from each tool will also be covered. These details will be presented, balanced with a spotlight on communication as a critical component of any project management undertaking. Using today's technology, the web arguably provides the most cost and resource effective vehicle to facilitate the broad based, interactive sharing of project information.

  17. Clinical experience with PACS at Northwestern: year two

    NASA Astrophysics Data System (ADS)

    Channin, David S.; Hawkins, Rodney C.; Enzmann, Dieter R.

    2001-08-01

    We have previously described the PACS configuration at Northwestern Memorial Hospital (NMH). As opposed to an imaging modality, PACS is an evolving system that continuously grows and changes to meet the needs of the institution. The NMH PACS has grown significantly in the past year and has undergone significant architectural enhancements. This growth and evolutionary change will be described and discussed. The system now contains over 339,000 studies consisting of over 13 million images. There are now two short-term RAID storage units that provide for twice as much fast storage. There are also two magneto-optical disk jukeboxes providing long-term archive. We have deployed a redundant database to improve reliability of the system in the event of database failure. The number of modalities connected to the system has increased and will be summarized. Statistics describing utilization of the PACS will be shown. Lastly, we will discuss our plans for exploiting the application service provider model in our PACS environment.

  18. DICOM modality worklist: an essential component in a PACS environment.

    PubMed

    Gale, M E; Gale, D R

    2000-08-01

    The development and acceptance of the digital communication in medicine (DICOM) standard has become a basic requirement for the implementation of electronic imaging in radiology. DICOM is now evolving to provide a standard for electronic communication between radiology and other parts of the hospital enterprise. In a completely integrated filmless radiology department, there are 3 core computer systems, the picture archiving and communication system (PACS), the hospital or radiology information system (HIS, RIS), and the acquisition modality. Ideally, each would have bidirectional communication with the other 2 systems. At a minimum, a PACS must be able to receive and acknowledge receipt of image and demographic data from the modalities. Similarly, the modalities must be able to send images and demographic data to the PACS. Now that basic DICOM communication protocols for query or retrieval, storage, and print classes have become established through both conformance statements and intervendor testing, there has been an increase in interest in enhancing the functionality of communication between the 3 computers. Historically, demographic data passed to the PACS have been generated manually at the modality despite the existence of the same data on the HIS or RIS. In more current sophisticated implementations, acquisition modalities are able to receive patient and study-related data from the HIS or RIS. DICOM Modality Worklist is the missing electronic link that transfers this critical information between the acquisition modalities and the HIS or RIS. This report describes the concepts, issues, and impact of DICOM Modality Worklist implementation in a PACS environment. PMID:15359747

  19. 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

    2014-08-01

    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. PMID:25019644

  20. 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.

  1. Vector potential and metric perturbations of a rotating black hole

    NASA Technical Reports Server (NTRS)

    Chrzanowski, P. L.

    1975-01-01

    The assumption of factorized Green's functions together with the inhomogeneous Teukolsky equations are used to derive analytic expressions for homogeneous metric (and vector potential) perturbations of a Kerr black hole. These homogeneous solutions are used to construct solutions to the perturbation equations when sources are present. What one finds are particularly simple formulas for the energy and angular momentum flux in the asymptotic regions at plus or minus infinity.-

  2. "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

    2014-03-01

    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. PMID:24656273

  3. Integrated modality, PACS, and RIS environment using the DICOM standard

    NASA Astrophysics Data System (ADS)

    Bao, Yongjian; Reyinger, Juergen; Rechid, Renas

    1998-07-01

    Interoperability of imaging devices (Modality), PACS and RIS is a crucial point determining the effectiveness and the performance of a digital diagnostic radiology department. This paper represents an integrated environment of Modality, PACS and RIS based on a communication interface using the DICOM standard. In the environment, RIS acts as the master system and provides overall image management and move control functions. This allows a considerably simplified interface design and an employment of standard DICOM services for the implementation. All important RIS - PACS inter-operation functions like Image Pre-fetching, Auto-Routing, Report Delivery, etc., are supported. Using the DICOM Standard, the system integration has been achieved with an open communication protocol and therefore is expected to be supported by various vendors.

  4. 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).

  5. Distribution of workload over the working day in a PACS

    NASA Astrophysics Data System (ADS)

    Wilson, Dennis L.; Smith, Donald V.

    1994-05-01

    A new radiological exam spawns a collection of image movements in a PACS system. Historical images are fetched, images are moved to workstations for diagnosis, selected images are moved to other workstations for clinicians and for consultations. The distributions of the new images over the working day will establish the image load to which the PACS system must respond. At Madigan Army Medical Center 10.1% of the daily load of images occurs in the busiest hour of the day. Individual days may have an hour that has up to 15% of the average daily load. The PACS system must be able to handle the images that are spawned by the average 10.1% busy hour load with margin to be able to handle a 50% overload with acceptable degradation of the performance of the system.

  6. Changes in technologist productivity with implementation of an enterprisewide PACS.

    PubMed

    Reiner, Bruce; Siegel, Eliot; Scanlon, Mary

    2002-03-01

    The purpose of this report is to determine what effect filmless operation has on technologist productivity when compared with traditional film-based operation. Retrospective data on technologist productivity was collected from the study institution before and after implementation of PACS using workload reports and payroll records. Departmentwide technologist productivity was defined as the number of examinations per full-time equivalent (exams/FTE) and correlated with local and nationwide standards operating in traditional film-based operations. During film-based operation, technologist productivity was comparable between the study institution and nationwide standards, allowing for the unique examination volumes and modality mix. After implementation of a large-scale PACS, technologist productivity was found to increase 34% above that of national standards and 48% that of the local control site. Implementation of an enterprisewide PACS offers the potential to significantly improve departmentwide technologist productivity when compared with traditional film-based operation. PMID:12134211

  7. 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.

  8. Monitoring the accuracy of a PACS image database.

    PubMed

    Blado, Maria Elissa; Tomlinson, Abigail

    2002-01-01

    "What you don't know won't hurt you" is a proverb that does not apply to a database on which patient lives depend. One of the core components of the picture Archiving and communications system (PACS) is an image database that contains the location and state of images and their corresponding demographic information. An image associated with the wrong patient name has potentially devastating implications, especially if the error is not caught early. This article describes how Texas Children's Hospital addresses the challenge of ensuring the accuracy of data of our PACS image database. It presents the routine checks that our PACS analysts perform every three hours and on a daily and monthly basis. These include steps involved in "fixing" exam data when an examination has missing or incorrect demographic information. In addition, this report compares how our institution assured accuracy of our film-based archive before PACS. Human error is the source of most inaccuracies in the image database, and automation such as bar code scanners and DICOM Modality Work List management have decreased their frequency, but without totally eliminating them. Some errors are routinely generated by the nature of radiology imaging operations and the limitations of devices for automating those operations. For example, computed tomography exams of the head, chest, and abdomen are routinely acquired during the same scan but must be separated into different exams for interpretation by different physicians. Factors contributing to inaccurate information include major system modifications, such as software or hardware upgrades, service interruptions, inaccurate problem descriptions provided by the user to the PACS analyst, and steps taken by the PACS analyst or technologist to correct errors. PMID:12105704

  9. Picture archiving and communication system (PACS): medical perspectives.

    PubMed

    Osteaux, M; Van den Broeck, R; Verhelle, F; de Mey, J

    1997-06-01

    PACS represents the natural evolution from the digital new modalities (US, CT, MRI,...) to a global digital environment, where the film based activities are progressively replaced by their digital counterpart. The advantages of the technique, as well as the drawbacks of the first implementations, are described. The "second generation" PACS concept is presented (modular architecture, progressive implementation, multivendor environment, integration with the Hospital Information System, standardization,...). As "case study", the example of the A.Z.-V.U.B. Hospital Implementation is described. PMID:9260397

  10. Humidity response of the Eberline model PAC-7 alpha instrument

    SciTech Connect

    McAtee, J.L.

    1981-04-01

    Response of the Eberline Model PAC-7 alpha instrument under varying relative humidity (RH) and temperature conditions was studied in an environmental chamber. Electric discharges resulting in spurious counts or in instrument paralysis occurred at 35 to 50% RH. Improvement in the RH level tolerated by the PAC-7 alpha instrument was obtained by conformal coating of the high-voltage region of the printed circuit (PC) board. Following this treatment, electric discharges occurred only at relatively high humidity levels and then as a result of high-voltage breakdown within the AC-24C probe rather than within the PC board.

  11. 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.

  12. 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.

  13. Angular momentum and star formation

    NASA Astrophysics Data System (ADS)

    Strittmatter, P. A.

    The present investigation is mainly concerned with the importance of high angular resolution observations in studies of star formation and, in particular, with elucidating the role which angular momentum plays in the process. A brief report is included on recent high angular resolution observations made with the Steward Observatory speckle camera system. A consideration of the angular momentum in interstellar clouds indicates that rotation precludes quasi-spherical contraction. A number of solutions to this angular momentum problem are examined, taking into account questions concerning the help provided by high angular resolution observations for an elucidation of the various possible scenarios of star formation. Technical aspects involved in obtaining suitable data are investigated. It is concluded that high angular resolution observations hold considerable promise for solving at least some of the problems associated with the role of angular momentum in star formation.

  14. 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

  15. 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…

  16. Angular momentum projected semiclassics

    NASA Astrophysics Data System (ADS)

    Hasse, Rainer W.

    1987-06-01

    By using angular momentum projected plane waves as wave functions, we derive semiclassical expressions for the single-particle propagator, the partition function, the nonlocal density matrix, the single-particle density and the one particle-one hole level density for fixed angular momentum and fixed z-component or summed over the z-components. Other quantities can be deduced from the propagator. In coordinate space ( r, r') the relevant quantities depend on |r-r'| instead of | r- r'| and in Wigner space ( R, P) they become proportional to the angular momentum constraints δ(| R × P|/ h̵-l) and δ( R × P) z/ h̵-m) . As applications we calculate the single-particle and one-particle-one hole level densities for harmonic oscillator and Hill-Wheeler box potentials and the imaginary part of the optical potential and its volume integral with an underlying harmonic oscillator potential and a zero range two-body interaction.

  17. PACS 2000: quality control using the task allocation chart

    NASA Astrophysics Data System (ADS)

    Norton, Gary S.; Romlein, John R.; Lyche, David K.; Richardson, Ronald R., Jr.

    2000-05-01

    Medical imaging's technological evolution in the next century will continue to include Picture Archive and Communication Systems (PACS) and teleradiology. It is difficult to predict radiology's future in the new millennium with both computed radiography and direct digital capture competing as the primary image acquisition methods for routine radiography. Changes in Computed Axial Tomography (CT) and Magnetic Resonance Imaging (MRI) continue to amaze the healthcare community. No matter how the acquisition, display, and archive functions change, Quality Control (QC) of the radiographic imaging chain will remain an important step in the imaging process. The Task Allocation Chart (TAC) is a tool that can be used in a medical facility's QC process to indicate the testing responsibilities of the image stakeholders and the medical informatics department. The TAC shows a grid of equipment to be serviced, tasks to be performed, and the organization assigned to perform each task. Additionally, skills, tasks, time, and references for each task can be provided. QC of the PACS must be stressed as a primary element of a PACS' implementation. The TAC can be used to clarify responsibilities during warranty and paid maintenance periods. Establishing a TAC a part of a PACS implementation has a positive affect on patient care and clinical acceptance.

  18. 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.

  19. Preprocessing functions for computed radiography images in a PACS environment

    NASA Astrophysics Data System (ADS)

    McNitt-Gray, Michael F.; Pietka, Ewa; Huang, H. K.

    1992-05-01

    In a picture archiving and communications system (PACS), images are acquired from several modalities including computed radiography (CR). This modality has unique image characteristics and presents several problems that need to be resolved before the image is available for viewing at a display workstation. A set of preprocessing functions have been applied to all CR images in a PACS environment to enhance the display of images. The first function reformats CR images that are acquired with different plate sizes to a standard size for display. Another function removes the distracting white background caused by the collimation used at the time of exposure. A third function determines the orientation of each image and rotates those images that are in nonstandard positions into a standard viewing position. Another function creates a default look-up table based on the gray levels actually used by the image (instead of allocated gray levels). Finally, there is a function which creates (for chest images only) the piece-wise linear look-up tables that can be applied to enhance different tissue densities. These functions have all been implemented in a PACS environment. Each of these functions have been very successful in improving the viewing conditions of CR images and contribute to the clinical acceptance of PACS by reducing the effort required to display CR images.

  20. Maxadilan, a PAC1 receptor agonist from sand flies

    PubMed Central

    Lerner, Ethan A.; Iuga, Aurel O.; Reddy, Vemuri B.

    2007-01-01

    In 1991, a potent 61 amino acid vasodilator peptide, named maxadilan, was isolated from the salivary glands of the sand fly. Subsequently, it was shown that this peptide specifically and potently activated the mammalian PAC1 receptor, one of the three receptors for PACAP. These studies and the link between maxadilan and leishmaniasis are discussed. PMID:17681401

  1. 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.

  2. 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. PMID:9735424

  3. PACS and diagnostic imaging service delivery--a UK perspective.

    PubMed

    Sutton, Laurence N

    2011-05-01

    This review sets out the current position with regard to the implementation of PACS throughout the United Kingdom and the impact this has had on improving patient care. In December 2007 England had implemented full hospital-wide PACS in all hospitals: a major achievement in the relatively short time period of three years. The different approaches used by each country of the UK to achieve full national PACS are described in addition to the current issues with the sharing of images and reports across different healthcare organisations with regard to technical solutions, clinical safety and governance. The review gives insight into the changing methods of service delivery to address increasing demand pressures on diagnostic imaging services and how the national PACS implementation, specifically in England, has made a significant contribution to measures to improve efficiencies. The role of Teleradiology is discussed in the context of supporting local patient services rather than undermining them and the concept of cross-healthcare reporting 'Grids' is described. Finally, in the summary it is recognised that the vast wealth of knowledge accumulated during the national implementations has placed the UK in a strong position to facilitate full national data sharing across all healthcare organisations to improve patient care. PMID:21600402

  4. NARSTO PAC2001 CESSNA VOC PM OZONE MET DATA

    Atmospheric Science Data Center

    2014-04-25

    NARSTO PAC2001 CESSNA VOC PM OZONE MET DATA Project Title:  NARSTO Discipline:  ... Temperature Probe Humidity Probe Wind Sensor UV Ozone Detector Optical Counter GC Location:  Lower Fraser ... Air Temperature Humidity Upper Level Winds Ozone Aerosol Particle Properties Volatile Organic Compounds ...

  5. NARSTO PAC2001 CONVAIR PM OZONE MET DATA

    Atmospheric Science Data Center

    2014-04-25

    NARSTO PAC2001 CONVAIR PM OZONE MET DATA Project Title:  NARSTO Discipline:  ... Temperature Probe Humidity Probe Wind Sensor UV Ozone Detector Optical Counter Location:  Lower Fraser ... Air Temperature Humidity Upper Level Winds Ozone Aerosol Particle Properties Order Data:  ASDC Order ...

  6. PACS model based on digital watermarking and its core algorithms

    NASA Astrophysics Data System (ADS)

    Que, Dashun; Wen, Xianlin; Chen, Bi

    2009-10-01

    PACS model based on digital watermarking is proposed by analyzing medical image features and PACS requirements from the point of view of information security, its core being digital watermarking server and the corresponding processing module. Two kinds of digital watermarking algorithm are studied; one is non-region of interest (NROI) digital watermarking algorithm based on wavelet domain and block-mean, the other is reversible watermarking algorithm on extended difference and pseudo-random matrix. The former belongs to robust lossy watermarking, which embedded in NROI by wavelet provides a good way for protecting the focus area (ROI) of images, and introduction of block-mean approach a good scheme to enhance the anti-attack capability; the latter belongs to fragile lossless watermarking, which has the performance of simple implementation and can realize tamper localization effectively, and the pseudo-random matrix enhances the correlation and security between pixels. Plenty of experimental research has been completed in this paper, including the realization of digital watermarking PACS model, the watermarking processing module and its anti-attack experiments, the digital watermarking server and the network transmission simulating experiments of medical images. Theoretical analysis and experimental results show that the designed PACS model can effectively ensure confidentiality, authenticity, integrity and security of medical image information.

  7. 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.

  8. 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.

  9. 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

  10. 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. PMID:12620309

  11. 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.

  12. Frame independent cosmological perturbations

    SciTech Connect

    Prokopec, Tomislav; Weenink, Jan E-mail: j.g.weenink@uu.nl

    2013-09-01

    We compute the third order gauge invariant action for scalar-graviton interactions in the Jordan frame. We demonstrate that the gauge invariant action for scalar and tensor perturbations on one physical hypersurface only differs from that on another physical hypersurface via terms proportional to the equation of motion and boundary terms, such that the evolution of non-Gaussianity may be called unique. Moreover, we demonstrate that the gauge invariant curvature perturbation and graviton on uniform field hypersurfaces in the Jordan frame are equal to their counterparts in the Einstein frame. These frame independent perturbations are therefore particularly useful in relating results in different frames at the perturbative level. On the other hand, the field perturbation and graviton on uniform curvature hypersurfaces in the Jordan and Einstein frame are non-linearly related, as are their corresponding actions and n-point functions.

  13. Quark Orbital Angular Momentum

    NASA Astrophysics Data System (ADS)

    Burkardt, Matthias

    2016-06-01

    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.

  14. 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. PMID:22264429

  15. Inflationary tensor perturbations after BICEP2.

    PubMed

    Caligiuri, Jerod; Kosowsky, Arthur

    2014-05-16

    The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-Universe inflation with a surprisingly large amplitude. The power spectrum of these tensor perturbations can be probed both with further measurements of the microwave background polarization at smaller scales and also directly via interferometry in space. We show that sufficiently sensitive high-resolution B-mode measurements will ultimately have the ability to test the inflationary consistency relation between the amplitude and spectrum of the tensor perturbations, confirming their inflationary origin. Additionally, a precise B-mode measurement of the tensor spectrum will predict the tensor amplitude on solar system scales to 20% accuracy for an exact power-law tensor spectrum, so a direct detection will then measure the running of the tensor spectral index to high precision. PMID:24877926

  16. 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.

  17. Uniaxial angular accelerometers

    NASA Astrophysics Data System (ADS)

    Seleznev, A. V.; Shvab, I. A.

    1985-05-01

    The basic mechanical components of an angular accelerometer are the sensor, the damper, and the transducer. Penumatic dampers are simplest in construction, but the viscosity of air is very low and, therefore, dampers with special purpose oils having a high temperature stability (synthetic silicon or organosilicon oils) are most widely used. The most common types of viscous dampers are lamellar with meshed opposed arrays of fixed and movable vanes in the dashpot, piston dampers regulated by an adjustable-length capillary tube, and dampers with paddle wheel in closed tank. Another type of damper is an impact-inertial one with large masses absorbing the rotational energy upon collision with the sensor. Conventional measuring elements are resistive, capacitive, electromagnetic, photoelectric, and penumatic or hydraulic. Novel types of angular accelerometers are based on inertia of gas jets, electron beams, and ion beams, the piezoelectric effect in p-n junctions of diode and transistors, the electrokinetic effect in fluids, and cryogenic suspension of the sensor.

  18. 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

  19. PACS workstation for computer-assisted image diagnosis

    NASA Astrophysics Data System (ADS)

    Hosoba, Minoru; Horino, Masato; Takemura, Kunihiko; Wani, Hidenobu; Hidaka, Akinari; Hatabu, Hiroto; Kasagi, Kanji; Konishi, Junji

    1990-08-01

    Major two functions that a PACS workstation is considered to be equipped with are 1) efficient retrieval of image data and 2) supporting or consultation of writing reports, as radiologists have to diagnose increasing number of digital images in routine clinical studies. The authors developed a prototype PACS workstation with high speed image retrieving architecture and computer aided diagnosis and reporting function by using an artificial intelligence technology (AIPACS workstation). When physician selects the patient and his studies, the system performs feature extraction and generates diagnostic report by the inference engine with backward reasoning using the knowledge installed as production rules. Clinical application to the system for thyroid diagnosis showed good correlation with the diagnosis done by the physician.

  20. 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. PMID:27471299

  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. 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. Toshiba General Hospital PACS for routine in- and outpatient clinics

    NASA Astrophysics Data System (ADS)

    Toshimitsu, Akihiro; Okazaki, Nobuo; Kura, Hiroyuki; Nishihara, Eitaro; Tsubura, Shinichi

    1996-05-01

    The Toshiba General Hospital introduced a departmental RIS/PACS (Radiology Information System/Picture Archiving and Communication System) in the radiology department in May, 1993. It has been used routinely since that time. In order to provide efficient means for clinicians to find and read many images, the system has been expanded to the neurosurgery and urology clinics and wards since May, 1995, and five image referring workstations now provide digital images to clinicians. In this paper we discuss an algorithm for image migration, one of the key issues to accomplish the expansion to outpatient clinics successfully, and propose the WYWIWYG (what you want is what you get) image transfer logic. This is the logic used to transfer images that physicians require refer without increasing the traffic between the image server and referring workstations. We accomplish the WYWIWYG logic by prioritizing exams the physicians have not yet viewed and by finding historical exams according to the modality, anatomy, and marking. Clinicians gave us comments from their first use of the system and suggested that the PACS enables clinicians to review images more efficiently compared to a film-based system. Our experience suggests that it is a key to the effective application of PACS in outpatient clinics to incorporate consideration patterns of clinicians on the migration algorithm.

  4. PACS according to Murphy: what can and will go wrong

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Arreola, Manuel; Frost, Meryll M.

    2002-05-01

    A multi-institutional PACS and electronic radiology practice is in daily operation based at the University of Florida. This system is evolving constantly as technology advances and users become more sophisticated. As the technology advances, however, more things can and do go wrong. The PACS quality control and working groups at the University have compile the problems that have been encountered is this rapidly changing environment and have designed tools or procedures to either eliminate the problems or to minimize their impact on the operation of the system. As a result, a series of automated tools have been created to correct mislabeled images, to monitor the correct operation of the system, and to inform support of problems as soon as they are discovered. In the case where automated tools cannot solve the problem, protocols have been designed and procedures developed to identify issues and resolve them before time is wasted or the system fails. Not every problem can be anticipated and solved prior to it occurring, but this work can help alert new users and perhaps even experienced users to unanticipated disasters with PACS and other technologies associated with an electronic radiology practice.

  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. 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. PMID:20981467

  7. 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.

  8. On the relation between angular momentum and angular velocity

    NASA Astrophysics Data System (ADS)

    Silva, J. P.; Tavares, J. M.

    2007-01-01

    Students of mechanics usually have difficulties when they learn about the rotation of a rigid body. These difficulties are rooted in the relation between angular momentum and angular velocity, because these vectors are not parallel, and we need in general to utilize a rotating frame of reference or a time dependent inertia tensor. We discuss a series of problems that introduce both difficulties.

  9. Chiral Perturbation Theory

    NASA Astrophysics Data System (ADS)

    Tiburzi, Brian C.

    The era of high-precision lattice QCD has led to synergy between lattice computations and phenomenological input from chiral perturbation theory. We provide an introduction to chiral perturbation theory with a bent towards understanding properties of the nucleon and other low-lying baryons. Four main topics are the basis for this chapter. We begin with a discussion of broken symmetries and the procedure to construct the chiral Lagrangian. The second topic concerns specialized applications of chiral perturbation theory tailored to lattice QCD, such as partial quenching, lattice discretization, and finite-volume effects. We describe inclusion of the nucleon in chiral perturbation theory using a heavy-fermion Euclidean action. Issues of convergence are taken up as our final topic. We consider expansions in powers of the strange-quark mass, and the appearance of unphysical singularities in the heavy-particle formulation. Our aim is to guide lattice practitioners in understanding the predictions chiral perturbation theory makes for baryons, and show how the lattice will play a role in testing the rigor of the chiral expansion at physical values of the quark masses.

  10. 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)