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S Chekanov - One of the best experts on this subject based on the ideXlab platform.
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a qcd analysis of Zeus diffractive data
Nuclear Physics, 2010Co-Authors: S Chekanov, G Grigorescu, A Keramidas, E Koffeman, P Kooijman, A Pellegrino, H Tiecke, M Vazquez, L WiggersAbstract:Zeus inclusive diffractive-cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (C) 2010 Elsevier B.V. All rights reserved.
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Zeus next to leading order qcd analysis of data on deep inelastic scattering
Physical Review D, 2003Co-Authors: S Chekanov, B Musgrave, J Repond, D Krakauer, S Magill, R Yoshida, P Antonioli, G Bari, M Basile, Lorenzo BellagambaAbstract:Next-to-leading-order QCD analyses of the Zeus data on deep inelastic scattering together with fixed-target data have been performed, from which the gluon and quark densities of the proton and the value of the strong coupling constant alpha(s)(M-Z) were extracted. The study includes a full treatment of the experimental systematic uncertainties including point-to-point correlations. The resulting uncertainties in the parton density functions are presented. A combined fit for alpha(s)(M-Z) and the gluon and quark densities yields a value for alpha(s)(M-Z) in agreement with the world average. The parton density functions derived from Zeus data alone indicate the importance of HERA data in determining the sea quark and gluon distributions at low x. The limits of applicability of the theoretical formalism have been explored by comparing the fit predictions to Zeus data at very low Q(2).
Jan F. A. Hendrickx - One of the best experts on this subject based on the ideXlab platform.
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desflurane consumption with the Zeus during automated closed circuit versus low flow anesthesia
Acta anaesthesiologica Belgica, 2009Co-Authors: Sofie De Cooman, A Lecain, Maurice Sosnowski, A M De Wolf, Jan F. A. HendrickxAbstract:During automated closed-circuit anesthesia (CCA), the Zeus (Drager, Lubeck, Germany) uses a high initial fresh gas flow (FGF) to rapidly attain the desired agent and carrier gas concentrations, resulting in a desflurane consumption well above patient uptake. Because both FGF and carrier gas composition can affect consumption, we determined the Zeus' agent consumption with automated CCA and with automated low flow anesthesia (LFA) (= maintenance FGF of 0.7 L min(-1)) with 3 different carrier gases.
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desflurane consumption during automated closed circuit delivery is higher than when a conventional anesthesia machine is used with a simple vaporizer o2 n2o fresh gas flow sequence
BMC Anesthesiology, 2008Co-Authors: Sofie De Cooman, Maurice Sosnowski, A M De Wolf, Nathalie De Mey, Bram B C Dewulf, Rik Carette, Thierry Deloof, Jan F. A. HendrickxAbstract:Background: The Zeus ® (Drager, Lubeck, Germany), an automated closed-circuit anesthesia machine, uses high fresh gas flows (FGF) to wash-in the circuit and the lungs, and intermittently flushes the system to remove unwanted N 2 . We hypothesized this could increase desflurane consumption to such an extent that agent consumption might become higher than with a conventional anesthesia machine (Anesthesia Delivery Unit [ADU ® ], GE, Helsinki, Finland) used with a previously derived desflurane-O2-N2O administration schedule that allows early FGF reduction. Methods: Thirty-four ASA PS I or II patients undergoing plastic, urologic, or gynecologic surgery received desflurane in O 2 /N 2 O. In the ADU group (n = 24), an initial 3 min high FGF of O 2 and N 2 O (2 and 4 L.min-1, respectively) was used, followed by 0.3 L.min -1 O2 + 0.4 L.min -1 N2O. The desflurane vaporizer setting (FD) was 6.5% for the first 15 min, and 5.5% during the next 25 min. In the Zeus group (n = 10), the Zeus ® was used in automated closed circuit anesthesia mode with a selected end-expired (F A ) desflurane target of 4.6%, and O 2 /N 2 O as the carrier gases with a target inspired O2% of 30%. Desflurane FA and consumption during the first 40 min were compared using repeated measures one-way ANOVA. Results: Age and weight did not differ between the groups (P > 0.05), but patients in the Zeus group were taller (P = 0.04). In the Zeus group, the desflurane F A was lower during the first 3 min (P 0.05), and slightly higher after 4 min (P < 0.05). Desflurane consumption was higher in the Zeus group at all times, a difference that persisted after correcting for the small difference in FA between the two groups. Conclusion: Agent consumption with an automated closed-circuit anesthesia machine is higher than with a conventional anesthesia machine when the latter is used with a specific vaporizer-FGF sequence. Agent consumption during automated delivery might be further reduced by optimizing the algorithm(s) that manages the initial FGF or by tolerating some N2 in the circuit to minimize the need for intermittent flushing.
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Desflurane consumption during automated closed-circuit delivery is higher than when a conventional anesthesia machine is used with a simple vaporizer-O_2-N_2O fresh gas flow sequence
BMC Anesthesiology, 2008Co-Authors: Sofie De Cooman, Maurice Sosnowski, A M De Wolf, Bram B C Dewulf, Rik Carette, Thierry Deloof, Jan F. A. HendrickxAbstract:Background The Zeus^® (Dräger, Lübeck, Germany), an automated closed-circuit anesthesia machine, uses high fresh gas flows (FGF) to wash-in the circuit and the lungs, and intermittently flushes the system to remove unwanted N_2. We hypothesized this could increase desflurane consumption to such an extent that agent consumption might become higher than with a conventional anesthesia machine (Anesthesia Delivery Unit [ADU^®], GE, Helsinki, Finland) used with a previously derived desflurane-O_2-N_2O administration schedule that allows early FGF reduction. Methods Thirty-four ASA PS I or II patients undergoing plastic, urologic, or gynecologic surgery received desflurane in O_2/N_2O. In the ADU group (n = 24), an initial 3 min high FGF of O_2 and N_2O (2 and 4 L.min^-1, respectively) was used, followed by 0.3 L.min^-1 O_2 + 0.4 L.min^-1 N_2O. The desflurane vaporizer setting (F_D) was 6.5% for the first 15 min, and 5.5% during the next 25 min. In the Zeus group (n = 10), the Zeus^® was used in automated closed circuit anesthesia mode with a selected end-expired (F_A) desflurane target of 4.6%, and O_2/N_2O as the carrier gases with a target inspired O_2% of 30%. Desflurane F_A and consumption during the first 40 min were compared using repeated measures one-way ANOVA. Results Age and weight did not differ between the groups (P > 0.05), but patients in the Zeus group were taller (P = 0.04). In the Zeus group, the desflurane F_A was lower during the first 3 min (P < 0.05), identical at 4 min (P > 0.05), and slightly higher after 4 min (P < 0.05). Desflurane consumption was higher in the Zeus group at all times, a difference that persisted after correcting for the small difference in F_A between the two groups. Conclusion Agent consumption with an automated closed-circuit anesthesia machine is higher than with a conventional anesthesia machine when the latter is used with a specific vaporizer-FGF sequence. Agent consumption during automated delivery might be further reduced by optimizing the algorithm(s) that manages the initial FGF or by tolerating some N_2 in the circuit to minimize the need for intermittent flushing.
Inderbir S Gill - One of the best experts on this subject based on the ideXlab platform.
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robotic laparoscopic surgery a comparison of the da vinci and Zeus systems
Urology, 2001Co-Authors: Gyung Tak Sung, Inderbir S GillAbstract:Abstract Objectives. To evaluate two currently available robotic surgical systems in performing various urologic laparoscopic procedures in an acute porcine model. Methods. Robotic laparoscopic surgery was performed in 14 swine. Data were compared between the da Vinci Robotic System and the Zeus Robotic System. Results. During laparoscopic nephrectomy, the da Vinci System (n = 6) had a significantly shorter total operating room time (51.3 versus 71.6 minutes; P = 0.02) and actual surgical time (42.1 versus 61.4 minutes; P = 0.03) compared with the Zeus System (n = 5). However, the blood loss and adequacy of surgical dissection were comparable between the two groups. For laparoscopic adrenalectomy, the da Vinci System (n = 5) had a shorter actual surgical time (12.2 versus 26.0 minutes; P = 0.006) than did the Zeus System (n = 5). For laparoscopic pyeloplasty, the da Vinci System had a shorter total operating room time (61.4 versus 83.4 minutes; P = 0.10) and anastomotic time (44.7 versus 66.4 minutes; P = 0.11). During pyeloplasty anastomosis, the total number of suture bites per ureter was 13.0 for the da Vinci System (n = 6) and 10.8 for the Zeus System (n = 6). The complications included an adrenal parenchymal tear each during a da Vinci System-based left adrenalectomy and a Zeus System-based right adrenalectomy. An inferior vena caval tear during a Zeus System-based right adrenalectomy occurred in 1 case, which was suture-repaired telerobotically. Conclusions. Robotic laparoscopic procedures can be performed effectively using either the da Vinci or Zeus System. In this limited study, the learning curve and operative times were shorter and the intraoperative technical movements appeared inherently more intuitive with the da Vinci System. Additional clinical experience is necessary.
L Wiggers - One of the best experts on this subject based on the ideXlab platform.
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a qcd analysis of Zeus diffractive data
Nuclear Physics, 2010Co-Authors: S Chekanov, G Grigorescu, A Keramidas, E Koffeman, P Kooijman, A Pellegrino, H Tiecke, M Vazquez, L WiggersAbstract:Zeus inclusive diffractive-cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (C) 2010 Elsevier B.V. All rights reserved.
Michael L Norman - One of the best experts on this subject based on the ideXlab platform.
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simulating radiating and magnetized flows in multiple dimensions with Zeus mp
Astrophysical Journal Supplement Series, 2006Co-Authors: John C Hayes, Michael L Norman, James Bordner, S E Clark, A Uddoula, Robert Fiedler, Mordecaimark Mac LowAbstract:This paper describes Zeus-MP, a multi-physics, massively parallel, message-passing implementation of the Zeus code. Zeus-MP differs significantly from the thoroughly documented Zeus-2D code, the completely undocumented (in peer-reviewed literature) Zeus-3D code, and a marginally documented “version 1” of Zeus-MP first distributed publicly in 1999. Zeus-MP offers an MHD algorithm which is better suited for multidimensional flows than the Zeus-2D module by virtue of modifications to the Method of Characteristics scheme first suggested by Hawley & Stone (1995). This MHD module is shown to compare quite favorably to the TVD scheme described by Ryu et al. (1998). Zeus-MP is the first publicly-available Zeus code to allow the advection of multiple chemical (or nuclear) species. Radiation hydrodynamic simulations are enabled via an implicit flux-limited radiation diffusion (FLD) module. The hydrodynamic, MHD, and FLD modules may be used, singly or in concert, in one, two, or three space dimensions. Additionally, so-called “1.5-D” and “2.5-D” grids, in which the “half-D” denotes a symmetry axis along which a constant but non-zero value of velocity or magnetic field is evolved, are supported. Self gravity may be included either through the assumption of a GM/r potential or a solution of Poisson’s equation using one of three linear solver packages (conjugategradient, multigrid, and FFT) provided for that purpose. Point-mass potentials are also supported. Because Zeus-MP is designed for large simulations on parallel computing platforms, considerable attention is paid to the parallel performance characteristics of each module in the code. Strong-scaling tests involving pure hydrodynamics (with and without self-gravity), MHD, and RHD are performed in which large problems (256 3 zones) are distributed among as many as 1024 processors of an IBM SP3. Parallel efficiency is a strong function of the amount of communication required between processors in a given algorithm, but all modules are shown to scale well on up to 1024 processors for the chosen fixed problem size. Subject headings: hydrodynamics – methods:numerical – methods:parallel – MHD – radiative transfer
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simulating radiating and magnetized flows in multi dimensions with Zeus mp
arXiv: Astrophysics, 2005Co-Authors: John C Hayes, Michael L Norman, R A Fiedler, James Bordner, S E Clark, A Uddoula, Mordecaimark Mac LowAbstract:This paper describes Zeus-MP, a multi-physics, massively parallel, message- passing implementation of the Zeus code. Zeus-MP differs significantly from the Zeus-2D code, the Zeus-3D code, and an early "version 1" of Zeus-MP distributed publicly in 1999. Zeus-MP offers an MHD algorithm better suited for multidimensional flows than the Zeus-2D module by virtue of modifications to the Method of Characteristics scheme first suggested by Hawley and Stone (1995), and is shown to compare quite favorably to the TVD scheme described by Ryu et. al (1998). Zeus-MP is the first publicly-available Zeus code to allow the advection of multiple chemical (or nuclear) species. Radiation hydrodynamic simulations are enabled via an implicit flux-limited radiation diffusion (FLD) module. The hydrodynamic, MHD, and FLD modules may be used in one, two, or three space dimensions. Self gravity may be included either through the assumption of a GM/r potential or a solution of Poisson's equation using one of three linear solver packages (conjugate-gradient, multigrid, and FFT) provided for that purpose. Point-mass potentials are also supported. Because Zeus-MP is designed for simulations on parallel computing platforms, considerable attention is paid to the parallel performance characteristics of each module. Strong-scaling tests involving pure hydrodynamics (with and without self-gravity), MHD, and RHD are performed in which large problems (256^3 zones) are distributed among as many as 1024 processors of an IBM SP3. Parallel efficiency is a strong function of the amount of communication required between processors in a given algorithm, but all modules are shown to scale well on up to 1024 processors for the chosen fixed problem size.
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Zeus 2d a radiation magnetohydrodynamics code for astrophysical flows in two space dimensions ii the magnetohydrodynamic algorithms and tests
Astrophysical Journal Supplement Series, 1992Co-Authors: James M Stone, Michael L NormanAbstract:In this, the second of a series of three papers, we continue a detailed description of Zeus-2D, a numerical code for the simulation of fluid dynamical flows in astrophysics including a self-consistent treatment of the effects of magnetic fields and radiation transfer. Here, a detailed description of the magnetohydrodynamical (MHD) algorithms in Zeus-2D is given. The recently developed constrained transport (CT) algorithm is implemented for the numerical evolution of the components of the magnetic field for MHD simulations. This formalism guarantees the numerically evolved field components will satisfy the divergence-free constraint at all times
