Absolute Mode Research Articles

Влияние гипероксии на состояние гуморального и клеточного звена иммунобиологической резистентности здорового организма крыс в эксперименте

The paper contains information about hyperbaric oxygenation impact on humoral and cell components of immune-biological resistance of healthy rats. The following factors are analyzed: potency of oxygen-dependent enzyme systems (myeloperoxidase, oxidase), oxygen-independent systems (leukocyte lysozyme, cationic proteins), killing reactions of peripheral blood neutrophils, their phagocytic and oxidase reserve, complement activity and content of circulating immune complexes in the blood serum of healthy animals, which have been exposed to 60-minute sessions of hyperbaric oxygenation, over time from the 1st to the 30th day post hyperoxia period during experiment. A single session of hyperbaric oxygenation is carried out within 60 minutes (3 absolute atmospheres mode). Mechanisms of adaptation and pathological reactions formation by immune-biological surveillance system of healthy body in early and late post hyperoxia periods during experiment are considered.
 
 The paper shows that adaptive responses, which are designed to protect the body against aggressive action of oxygen under the influence of hyperbaric oxygenation, are formed in the bodies of healthy animals.
 
 The reactions of oxygen-dependent of phagocytes systems in conditions of hyperoxia manifested in the early stages of the research, persisting to the end of the observation and the reactions of oxygen independent - only at early stages. The humoral responses of healthy organism under hyperbaric oxygen are characterized by the change in complement activity and concentration of circulating immune complexes in blood serum. The received experimental data may be used as a theoretical explanation of indications for use of hyperbaric oxygen therapy and different hyperbaric oxygenation regimes.

Homogenization of time series from Portugal and its former colonies for the period from the late 19th to the early 21st century

Three homogenization software packages – AnClim, RhTestsV3 and HOMER – have been applied to monthly and annual temperature and pressure series from Portugal and its ex-colonies in Africa and Asia to detect non-climatic breaks. Homogenization tests in both absolute and relative mode were performed with an a posteriori statistical assessment to select the most probable breakpoints. Time series from neighbouring stations as well as reanalyses data were used as reference series. The reanalyses data sets were used due to lack of suitable neighbouring stations and also to test reanalyses as proxy data. A list of probable shifts is produced and will be used to support future global reanalyses. Moreover, temperature and pressure series were adjusted using adjustment factors that were obtained by calculating the difference between certain periods before and after the breaks. The accuracy of the adjusted series was verified subjectively (visually) and objectively using three verification methods: correlation coefficient, central root-mean-square error and standard deviation. A positive impact of the applied adjustment in terms of all three scores was found in a majority of cases.

Merging mind-sets: Training as a traditional Chinese scroll mounter within the British Museum, London, UK

We shall examine the contrast in conservation training styles between Western and traditional Chinese methods and how the commitment to such an absolute mode of training can actually widen one's pe...

SU-E-T-631: Commissioning and Comprehensive Evaluation of the ArcCHECK Cylindrical Diode Array for VMAT QA

Purpose: Commissioning and comprehensive evaluation of ArcCHECK phantom for dosimetry of VMAT QA, using 6MV photon beam with and without the flattening filter. Methods: ArcCHECK was evaluated for response dependency on linac dose rate, instantaneous dose rate, radiation field size, beam angle and couch insertion. Scatter dose characterization, consistency and symmetry of response, dosimetric accuracy of fixed aperture arcs and clinical VMAT plans were investigated. Measurements were done using TrueBeam™ STx accelerator (Console version 1.6) with a 6 MV beam with and without flattening filter. Reference dose-grids were calculated using Eclipse TPS Analytical Anisotropic Algorithm (AAA version 10.0.39). Planned doses were calculated using symmetric 2mm 3D dose grids with 4 degree angular resolution defaulted to each control point. Gamma evaluations were performed in absolute dose mode, with default normalization to maximum dose in the curved plane and a low dose threshold of 10% to restrict the analysis to clinically relevant areas. Global and local gamma indices at 3mm/3% and 2mm/2% level were computed using SNC software (version 6.0). Results: Results of gamma analysis demonstrated an overall agreement between ArcCHECK measured and TPS calculated reference doses. Field size dependency was within 0.5% of the reference. Dose-rate based dependency was well within 1% of the TPS reference and the angular dependency was ±3% of the reference, as tested for BEV angles. At the level of 3%/3mm, narrow and wide open arcs as well as clinical VMAT cases demonstrated high level of dosimetry accuracy in global gamma passing rates for both 6X and 6F beams. At the level of 2%/2mm two VMAT cases involving the narrow heavily modulated arcs demonstrated lower passing rates. Conclusion: ArcCHECK phantom with latest software and hardware upgrades is suitable for VMAT QA. For higher sensitivity of 2%/2mm gamma analysis, we intend to use it as one of the VMAT QA evaluation metrics.

TH‐C‐12A‐01: Develop a Patient‐Specific QA Program for Radiation Therapy with On‐Board MRI

Purpose:This work describes development of the first patient‐specific quality assurance (QA) program for magnetic resonance imaging guided radiation therapy (MR‐IGRT).Methods:The program consisted of following components: 1) multipoint ionization chamber (IC) measurement using a 15 cm3 cubic phantom, 2) 2D stacked radiographic film dosimetry using a 30×30×20 cm3 phantom with multiple inserted ICs, 3) 3D ArcCHECK measurement with a centrally inserted IC, 4) machine delivery file verification, 5) 3D Monte‐Carlo dose re‐calculation with machine delivery file and phantom CT, 6) 2‐head mode delivery validation in case of a malfunctioning head, and 7) independent beam‐on time calculation for non‐IMRT fields. Both ADCL calibrated ICs and ArcCHECK were MRI compatible. Experimental data were analyzed for the first 10 patients treated at our institution.Results:The customized phantoms allowed measuring multiple points with ICs in one delivery. Absolute IC measurements were all within 3% in all phantom geometry/shape/material combinations. Despite known uncertainty associated with film dosimetry, passing rates greater than 90% were achieved in both absolute and composite modes using TG‐129 criteria. Due to the simultaneous irradiation by three radiation sources, ArcCHECK was used as a 3D relative dosimeter with angular and energy dependences uncorrected. 95–100% passing rates were obtained and the centrally inserted IC measurement assured that the overall dose normalization was within 3%. Machine delivery file verification and MC recalculated dose to the phantom results showed 98–100% passing rates, providing opportunity of moving from gamma passing rates to patient DVHbased QA metrics. Same results were obtained for the 2‐head delivery mode. Manual beam‐on time calculation for non‐IMRT fields showed better than 5% agreement.Conclusion:We have successfully developed the first MRIGRT patient specific QA program by adopting experimental and computational dosimetry methods that were developed in the past decade for other radiation therapy modalities.

MO‐G‐BRE‐02: A Survey of IMRT QA Practices for More Than 800 Institutions

Purpose:A wide range of techniques and measurement devices are employed for IMRT QA, causing a large variation of accepted action limits and potential follow up for failing plans. Such procedures are not well established or accepted in the medical physics community. To achieve the goal of proving insight into current IMRT QA practices, we created an electronic IMRT QA survey. The survey was open to a variety of the most common QA devices and assessed the type of comparison to measurement, action limits, delivery methods, and clinical action for failing QA plans.Methods:We conducted an online survey through the Radiological Physics Center's (RPC) annual survey with the goal of ascertaining elements of routine patient‐specific IMRT QA. A total of 874 institutions responded to the survey. The questions ranged from asking for action limits, dosimeter type(s) used, delivery techniques, and actions taken when a plan fails IMRT QA.Results:The most common (52%) planar gamma criteria was 3%/3 mm with a 95% of pixels passing criteria. The most common QA device were diode arrays (48%). The most common first response to a plan failing QA was to re‐measure at the same point the point dose (89%), second was to re‐measure at a new point (13%), and third was to analyze the plan in relative instead of absolute mode (10%) (Does not add to 100% as not all institutions placed a response for each QA follow‐up option). Some institutions, however, claimed that they had never observed a plan failure.Conclusion:The survey provided insights into the way the community currently performs IMRT QA. This information will help in the push to standardize action limits among dosimeters.

Spin dephasing as a probe of mode temperature, motional state distributions, and heating rates in a two-dimensional ion crystal

We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional Wigner crystal of hundreds of $^9$Be$^+$. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \textbf{108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\frac{d\bar{n}}{dt}\sim 5$ s$^{-1}$ for our trap at a frequency of 795 kHz, where $\bar{n}$ is the mean occupation of quantized COM motion in the axial harmonic well.

Optimization of Composite Cloud Service Processing with Virtual Machines

By leveraging virtual machine (VM) technology, we optimize cloud system performance based on refined resource allocation, in processing user requests with composite services. Our contribution is three-fold. (1) We devise a VM resource allocation scheme with a minimized processing overhead for task execution. (2) We comprehensively investigate the best-suited task scheduling policy with different design parameters. (3) We also explore the best-suited resource sharing scheme with adjusteddivisible resource fractions on running tasks in terms of Proportional-share model (PSM), which can be split into absolute mode (called AAPSM) and relative mode (RAPSM). We implement a prototype system over a cluster environment deployed with 56 real VM instances, and summarized valuable experience from our evaluation. As the system runs in short supply, lightest workload first (LWF) is mostly recommended because it can minimize the overall response extension ratio (RER) for both sequential-mode tasks and parallel-mode tasks. In a competitive situation with over-commitment of resources, the best one is combining LWF with both AAPSM and RAPSM. It outperforms other solutions in the competitive situation, by 16 + % w.r.t. the worst-case response time and by 7.4 + % w.r.t. the fairness.

The Role of Symbol Form and Legend Design in Proportional Point Symbolised Maps: An Experimental Study in Thematic Map Design

Point symbols are the most commonly used proportional symbols in thematic mapping. Traditionally two types of symbols have been in use in this category proportional squares and circles. These studies have reported malfunctioning of these symbol forms in terms of the errors reflected in response outputs of the magnitudes both in absolute and relative modes when these are read from the symbols placed in map environments. This malfunctioning of the symbol among other factors was ascribed to the type and design of symbol form and the legend provided on these maps. This paper examines the deficiencies in symbol form design of proportional circles and squares together with the existing design practices of legend design. An effort will also be made to improve symbol form by (1) adding (a) uniform gray area fills (b) graded gray area fills in the open circle and square form together with (2) an improvement in legend deign and its organisation. These design improvements will be tested experimentally by measuring the resulting improvements in terms of both efficiency and effectiveness of visual information processing. The experimental results have shown enhancements in both efficiency and effectiveness in information processing from maps due to proposed design improvement.

ABSOLUTE AND CONVECTIVE INSTABILITY OF A CONFINED SWIRLING ANNULAR LIQUID LAYER

The linear temporal and spatial–temporal instability behavior of a confined swirling annular liquidlayer was investigated theoretically. The practical situation that motivated this investigation is thecore-annular film flow regime encountered in industrial heat transfer and the recessed gas-centeredswirl coaxial injector, usually used in liquid propellant rocket engines. The dispersion relation for theliquid layer was developed and a parametric study was performed using this relation on the temporaland spatial–temporal instability to test the influence of non-dimensional flow parameters on the sta-bility behavior of the layer. The temporal stability analysis shows that a larger non-dimensional outerinjector radius, Rossby number, and liquid Weber number would destabilize the confined annularliquid layer. A larger liquid-to-gas density ratio and velocity ratio would decrease the disturbancegrowth rate. In the spatial–temporal mode, the absolute growth rate can be affected by these param-eters. For a small value of liquid-to-gas density ratio, velocity ratio, and liquid Weber number, or agreat value of non-dimensional radius of confinement wall and Rossby number, the flow is absolutelyunstable. The wavelength predicted with spatial–temporal analysis is much larger than that predictedusing the temporal analysis. However, the wavelength rarely changes with these dimensionless pa-rameters in absolute instability mode.

Final report on EURAMET.M.P-K4.2010: Key and supplementary comparison of national pressure standards in the range 1 Pa to 15 kPa of absolute and gauge pressure

This report describes a EURAMET comparison of five European National Metrology Institutes in low gauge and absolute pressure in gas (nitrogen), denoted as EURAMET.M.P-K4.2010. Its main intention is to state equivalence of the pressure standards, in particular those based on the technology of force-balanced piston gauges such as e.g. FRS by Furness Controls, UK and FPG8601 by DHI-Fluke, USA. It covers the range from 1 Pa to 15 kPa, both gauge and absolute. The comparison in absolute mode serves as a EURAMET Key Comparison which can be linked to CCM.P-K4 and CCM.P-K2 via PTB. The comparison in gauge mode is a supplementary comparison.The comparison was carried out from September 2008 till October 2012. The participating laboratories were the following: CMI, INRIM, LNE, MIKES, PTB-Berlin (absolute pressure 1 kPa and below) and PTB-Braunschweig (absolute pressure 1 kPa and above and gauge pressure). CMI was the pilot laboratory and provided a transfer standard for the comparison. This transfer standard was also the laboratory standard of CMI at the same time, which resulted in a unique and logistically difficult star comparison.Both in gauge and absolute pressures all the participating institutes successfully proved their equivalence with respect to the reference value and all also proved mutual bilateral equivalences in all the points. All the participating laboratories are also equivalent with the reference values of CCM.P-K4 and CCM.P-K2 in the relevant points. The comparison also proved the ability of FPG8601 to serve as a transfer standard.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

High-Speed Interferometric FBG Interrogator With Dynamic and Absolute Wavelength Measurement Capability

A passive, interferometric wavelength demodulation technique has been extended to measure the absolute wavelengths of a multiplexed array of fiber Bragg grating sensors. The scheme retains its original strain resolution of 10 nε/√{Hz}. A proof-of-concept interrogation system was able to determine the absolute wavelength of Bragg peaks to within 20 pm (17 με). Static and dynamic Bragg grating strains were accurately demodulated in both absolute and relative wavelength measurement modes. This demonstration indicates that interferometric techniques are able to provide absolute, static and dynamic measurements of strain within a single platform.

Theoretical Simulations and Quantitative Magnetic Field Measurements for Eddy-Current Testing with an HTS SQUID System

The use of a Superconducting QUantum Interference Device (SQUID) magnetometer for quantitative measurements in eddy-current nondestructive evaluation is presented. The SQUID is used in absolute mode, and the magnetic field measurements are directly compared to theoretical results from both analytical and semi-analytical models. The measurements are taken in an ambient noise environment, and the excitation has the form of a double-rectangle printed-circuit-board coil. The configurations examined involve the coil in air and above aluminum plates with or without defects in the form of notches. Agreement between experimental and theoretical results is very good in all cases, showing that SQUID magnetometers can be used for quantitative magnetic field measurements and that modeling can be readily applied for parametric analysis and optimizations of the measurement configuration including excitation coils' design and frequency selection.

SU-E-T-213: Comparison of Two Methods for Patient Specific VMAT QA Using Portal Dosimetry and IBA MatriXX

Purpose: To quantitatively evaluate two Methods: portal dosimetry and MatriXX placed in a dedicated holder, for clinical VMAT patient specific QA using gamma analysis. Methods: 21 prostate VMAT double‐arc plans were generated in Eclipse. We used portal dosimetry and MatriXX to conduct plan verifications. Portal dosimetry, including the absolute dose mode, was commissioned according to Varians guide. The MatriXX was commissioned as per vendor manual. In our study, Matrixx was inserted in a dedicated holder that was mounted on a linac treatment head with 5.0cm effective depth from the surface to the detector plane. In this geometry, the MatriXX detector plane is always facing the source perpendicularly. Thus the angular corrections for MatriXX detectors were not required. Gamma index was calculated using appropriate values of dose difference and distance‐to‐agreement. The threshold value, used for excluding low dose regions, was set to 5%. In portal dosimetry, calculated dose and measured dose were auto‐aligned and gamma index was obtained in the absolute dose mode. Portal dosimetry system was calibrated weekly or as needed to ensure its optimal working conditions. Results: In the MatriXX measurement, the Bland Altman plot was used to show that, with 95% confidence level, the measured Dmax agreed with the calculated Dmax. Then the dose distributions measured from MatriXX were normalized to Dmax and IBA so±ftware was used for gamma analysis. For gamma index calculated with 3%/3mm, both portal dosimetry (98.6%±1.1%) and MatriXX (97.0%±1.1%) exhibit similar passing rates, with portal doismetry demonstrating slightly higher passing rates than MatriXX. Conclusion: This work indicates that for VMAT patient specific QA, a well calibrated portal dosimetry system can be equivalent to or better than the MatriXX system. Future endeavors may extend to the analysis of VMAT plans for other sites and exploration of the method using the MatriXX inserted in a MultiCube phantom.

Establishing a Continuous Chain of Traceability for Pressure Measurements up to 40 MPa

Abstract:An Ultrasonic Interferometer Manometer (UIM) has been in use as the primary pressure standard at the National Physical Laboratory in India (NPLI) for absolute and gauge modes up to 130 kPa since 1982. However, the primary pneumatic pressure standard in gauge mode up to 6 MPa was based on the performance of controlled clearance Piston Gauges (CCPG). The uncertainty of measurements in UIM and CCPG were of great concern in establishing the primary pneumatic pressure scale of NPLI. To bridge the gap between the high vacuum, both in absolute and gauge modes, pneumatic pressure and hydraulic pressure up to 1 GPa, a conscientious attempt has been made to establish a uniform scale in the entire pressure range from 1 × 10−4 to 1 × 109 Pa that utilizes the UIM as the primary pressure standard. This paper presents the results of this entire systematic exercise up to a pressure of 40 MPa, in terms of the characterization of the piston gauges by the method of cross floating in the overlapping pressure ranges,...

Homogenization of Portuguese long-term temperature data series: Lisbon, Coimbra and Porto

Abstract. Three long-term temperature data series measured in Portugal were studied to detect and correct non-climatic homogeneity breaks and are now available for future studies of climate variability. Series of monthly minimum (Tmin) and maximum (Tmax) temperatures measured in the three Portuguese meteorological stations of Lisbon (from 1856 to 2008), Coimbra (from 1865 to 2005) and Porto (from 1888 to 2001) were studied to detect and correct non-climatic breaks. These series, together with monthly series of average temperature (Taver) and temperature range (DTR) derived from them, were tested in order to detect breaks, using firstly metadata, secondly a visual analysis, and thirdly four widely used homogeneity tests: von Neumann ratio test, Buishand test, standard normal homogeneity test, and Pettitt test. The homogeneity tests were used in absolute (using temperature series themselves) and relative (using sea-surface temperature anomalies series obtained from HadISST2.0.0.0 close to the Portuguese coast or already corrected temperature series as reference series) modes. We considered the Tmin, Tmax and DTR series as most informative for the detection of breaks due to the fact that Tmin and Tmax could respond differently to changes in position of a thermometer or other changes in the instrument's environment; Taver series have been used mainly as control. The homogeneity tests showed strong inhomogeneity of the original data series, which could have both internal climatic and non-climatic origins. Breaks that were identified by the last three mentioned homogeneity tests were compared with available metadata containing data such as instrument changes, changes in station location and environment, observation procedures, etc. Significant breaks (significance 95% or more) that coincided with known dates of instrumental changes were corrected using standard procedures. It was also noted that some significant breaks, which could not be connected to known dates of any changes in the park of instruments or stations location and environment, were probably caused by large volcanic eruptions. The corrected series were again tested for homogeneity; the corrected series were considered free of non-climatic breaks when the tests of most of monthly series showed no significant (significance 95% or more) breaks that coincide with dates of known instrument changes. Corrected series are now available within the framework of ERA-CLIM FP7 project for future studies of climate variability (doi:10.1594/PANGAEA.785377).

Magnetic field variations and spatial configurations of long-period sunspot oscillations according to the SOHO data

The phenomenon of long-period sunspot oscillations with periods from several tens to a thousand minutes is studied using data on the magnetic field strength and sunspot coordinates obtained based on the SOHO MDI data. It has been indicated that oscillations of the sunspot magnetic field strength are related to relative and absolute horizontal oscillation modes, as a result of which certain limitations are imposed on the interpretation of the phenomenon.

Evaluation of Portal Dosimetry for VMAT Treatments

Evaluation of Portal Dosimetry for VMAT Treatments

SU-E-T-78: Feasibility Study on Use of Gafchromic EBT2 Film as an Absolute Dosimetry QA System for SBRT Treatment

Purpose: To establish the use of Gafchromic EBT2 film as an accurate and effective QA tool capable of providing absolute dosimetry for SBRT treatment plans. Methods: A dose calibration curve using the absolute dose response of Gafchromic EBT2 film after irradiation of known doses from 0 – 2500 cGy was created and used to compare planar doses created by the Pinnacle treatment planning system to EBT2 film dose responses after being irradiated with the patient's plan on a QA phantom of solid water. FilmQAPro 2012 software was used to compare the calculated andmeasured planar doses in absolute dose mode. Both manual and fiducial marker registration methods were performed. For manual registration, the film was adjusted using the software's movement tools in order to get the best agreement between the film and calculated planar dose. Intended as the primary method, fiducial marker registration involved marking the isocenter on the film at the time of plan delivery and then setting these marks to the isocenter of the calculated planar dose before comparison. Results: Two cases were chosen: a single arc that could not be measured with the Delta4 dosimetry system despite troubleshooting and another composite plan involving a non-coplanar arc. In both cases, the measured and calculated planar dose comparisons had a γ-index <1 when using ± 3% dose and ± 3mm DTA criteria for above 95% of the points for both relative and absolute registration without dose rescaling. Conclusions: Initial resultsshow that EBT2 film can serve as an adequate QA tool for the evaluation of patient specific QA involving SBRT. We found that film offers the superior spatial resolution needed for SBRT cases which involve extremely steep dose gradients and small areas of dose deposition. Additionally, film also performs well with SBRT plans involving non-coplanar beams or arcs.

SOLVING THE MODE IDENTIFICATION PROBLEM IN ASTEROSEISMOLOGY OF F STARS OBSERVED WITH KEPLER

Asteroseismology of F-type stars has been hindered by an ambiguity in identification of their oscillation modes. The regular mode pattern that makes this task trivial in cooler stars is masked by increased linewidths. The absolute mode frequencies, encapsulated in the asteroseismic variable epsilon, can help solve this impasse because the values of epsilon implied by the two possible mode identifications are distinct. We find that the correct epsilon can be deduced from the effective temperature and the linewidths and we apply these methods to a sample of solar-like oscillators observed with Kepler.