Small Systematic Errors Research Articles

Geometric Property of Large Format Digital Camera DMC II 140

Intergraph Z/I Imaging has released the large format digital frame camera DMC II 140, equipped with just one very large format CCD-array for the panchromatic band. The homogenous large format CCD does not require any stitching, which may enhance the system accuracy. Test flights in three height levels with 5cm up to 20cm ground sampling distance (GSD) have been used for accuracy analysis of this camera. Very small systematic image errors confirm the excellent camera geometry. The root mean square differences at independent check points for the height in the range of 0.7 GSD corresponds to the good image geometry and radiometric image quality.

First-principles theory of nonlocal screening in graphene

Using the quasiparticle (QP) self-consistent $\mathit{GW}$ (QS$\mathit{GW}$) and local-density approximations, we calculate the $q$-dependent static dielectric function of undoped graphene and derive an effective two-dimensional (2D) dielectric function corresponding to screening of point charges. In the $q$$\ensuremath{\rightarrow}$0 limit, the 2D dielectric constant is found to scale approximately as the square root of the macroscopic dielectric function. Its value is $\ensuremath{\simeq}4$, in agreement with the predictions of the Dirac model. At the same time, in contrast with the Dirac model, the dielectric function is strongly dependent on $q$. The QS$\mathit{GW}$ approximation is shown to describe QP levels very well, with small systematic errors analogous to bulk $\mathit{sp}$ semiconductors. Local-field effects are rather more important in graphene than in bulk semiconductors.

Measurement Accuracy of Non-invasively Obtained Central Blood Pressure: A Systematic Review and Meta-analysis

Blood pressures determined at different sites vary considerably. Non-invasive methods are available to estimate central aortic blood pressure, the blood pressure at the origin of all arterial pulses. These methods obtain estimated central blood pressure by calibration and/or mathematical calculations for peripheral pulse waveforms. However, the accuracy of these methods has not been systematically examined.The review aimed to synthesise the best evidence on the accuracy of non-invasive measurement methods for central blood pressure.Types of participantsStudies with adult patients receiving invasive and non-invasive measurements of central blood pressure were considered.Studies were considered for inclusion if the focus was accuracy of non-invasive central BP estimating methods compared to invasively obtained corresponding values.Studies examining agreement between measurements using non-invasive central blood pressure estimating methods compared to invasive corresponding values were considered.This review included the means and standard deviation of differences between estimated and invasively measured central blood pressure.The search sought to identify any relevant published or unpublished studies with a three-step search strategy.Two independent reviewers assessed methodological quality of studies by a critical appraisal tool modified from Cochrane Diagnostic Test Accuracy Working Group.We used an original form to extract from included studies all study characteristics possibly related to agreement.Inverse variance weighted approach and DerSimonian-Laird weights for the random effects model, which incorporates a between-study variance, were used to obtain pooled estimates of systematic and random error from individual study estimates of the mean and standard deviation of differences between the paired measurements. Heterogeneity was assessed using Cochran Q. All analyses were performed in Microsoft Excel 2003.Twenty eight studies were eligible for inclusion and critically appraised in this review. Appropriate data for agreement were extracted from papers or authors in 20 studies, which were further included in meta-analysis. Acquired peripheral waveforms in these studies were directly measured, calibrated to match invasively obtained aortic mean blood pressure and diastolic blood pressure, or calibrated using brachial blood pressure measured by sphygomomanometer, the cuff blood pressure. Estimated central blood pressure of the studies using the last totally non-invasively methods (real world practices) were subject to meta-analysis separately from studies with the former two invasive methods (theoretical practice). Of the invasive methods, mean difference of the estimated central blood pressure was small (-1.2 ± 4.2mmHg for central systolic blood pressure, -0.6 ± 2.1mmHg for central diastolic blood pressure, and -1.1 ± 5.3 mmHg for central pulse pressure). However, the errors of the non-invasive method inflated considerably (-8.1 ± 10.7mmHg for central systolic blood pressure, 8.8 ± 9.5mmHg for central diastolic blood pressure, and -11.8 ± 13.3 mmHg for central pulse pressure). The findings were similar in subgroup analysis by different central blood pressure methods and by validated cuff monitors.Current central blood pressure estimating methods are acceptable in theory with small systematic and random error. However, the error of these methods was evident when cuff blood pressure was used for calibration and probably made them clinically inapplicable.

Measurement Accuracy of Non-invasively Obtained Central Blood Pressure: A Systematic Review and Meta-analysis.

Blood pressures determined at different sites vary considerably. Non-invasive methods are available to estimate central aortic blood pressure, the blood pressure at the origin of all arterial pulses. These methods obtain estimated central blood pressure by calibration and/or mathematical calculations for peripheral pulse waveforms. However, the accuracy of these methods has not been systematically examined. The review aimed to synthesise the best evidence on the accuracy of non-invasive measurement methods for central blood pressure. Types of participantsStudies with adult patients receiving invasive and non-invasive measurements of central blood pressure were considered. Studies were considered for inclusion if the focus was accuracy of non-invasive central BP estimating methods compared to invasively obtained corresponding values. Studies examining agreement between measurements using non-invasive central blood pressure estimating methods compared to invasive corresponding values were considered. This review included the means and standard deviation of differences between estimated and invasively measured central blood pressure. The search sought to identify any relevant published or unpublished studies with a three-step search strategy. Two independent reviewers assessed methodological quality of studies by a critical appraisal tool modified from Cochrane Diagnostic Test Accuracy Working Group. We used an original form to extract from included studies all study characteristics possibly related to agreement. Inverse variance weighted approach and DerSimonian-Laird weights for the random effects model, which incorporates a between-study variance, were used to obtain pooled estimates of systematic and random error from individual study estimates of the mean and standard deviation of differences between the paired measurements. Heterogeneity was assessed using Cochran Q. All analyses were performed in Microsoft Excel 2003. Twenty eight studies were eligible for inclusion and critically appraised in this review. Appropriate data for agreement were extracted from papers or authors in 20 studies, which were further included in meta-analysis. Acquired peripheral waveforms in these studies were directly measured, calibrated to match invasively obtained aortic mean blood pressure and diastolic blood pressure, or calibrated using brachial blood pressure measured by sphygomomanometer, the cuff blood pressure. Estimated central blood pressure of the studies using the last totally non-invasively methods (real world practices) were subject to meta-analysis separately from studies with the former two invasive methods (theoretical practice). Of the invasive methods, mean difference of the estimated central blood pressure was small (-1.2 ± 4.2mmHg for central systolic blood pressure, -0.6 ± 2.1mmHg for central diastolic blood pressure, and -1.1 ± 5.3 mmHg for central pulse pressure). However, the errors of the non-invasive method inflated considerably (-8.1 ± 10.7mmHg for central systolic blood pressure, 8.8 ± 9.5mmHg for central diastolic blood pressure, and -11.8 ± 13.3 mmHg for central pulse pressure). The findings were similar in subgroup analysis by different central blood pressure methods and by validated cuff monitors. Current central blood pressure estimating methods are acceptable in theory with small systematic and random error. However, the error of these methods was evident when cuff blood pressure was used for calibration and probably made them clinically inapplicable.

Error analysis of proper motions in decination obtained for 807 Hipparcos stars from PZT observations over many decades

AbstractAfter publication of the Hipparcos catalogue (in 1997), a few new astrometric catalogues have appeared (TYCHO‐2, ARIHIP, etc.), as a good combination of the Hipparcos satellite and ground‐based data, to get more accurate coordinates and proper motions of stars than the Hipparcos catalogue ones. There are also investigations on improving the Hipparcos coordinates and proper motions by using the astrometric observations of latitude and universal time variations (via observed stars referred to Hipparcos catalogue), together with Hipparcos data, carried out during the last few years. These kind of ground‐based data were collected at the end of the last century by J. Vondrák. There are about 4.4 million optical observations made worldwide at 33 observatories and with 47 instruments during 1899.7–1992.0; our Belgrade visual zenith telescope data (for the period 1949.0‐1986.0) were included. First of all, these data were used to determine the Earth Orientation Parameters – EOP, but they are also useful for the opposite task – to check the accuracy of coordinates and proper motions of Hipparcos stars which were observed from the ground over many decades. Here, we use the latitude part of ten Photographic Zenith Tubes – PZT data (more than 0.9 million observations made at 6 observatories during the time interval 1915.8–1992.0), and combine them with the Hipparcos catalogue ones, with suitable weights, in order to check the proper motions in declination for 807 common PZT/Hipparcos stars (and to construct the PZT catalogue of μδ for 807 stars). Our standard errors in proper motions in declination of these stars are less than or equal to the Hipparcos ones for 423 stars. The mean value of standard errors of 313 stars observed over more than 20 years by PZT is 0.40 mas/yr. This is 53% of 0.75 mas/yr (the suitable value from the Hipparcos catalogue). We used the Least Squares Method – LSM with the linear model. Our results are in good agreement with the Earth Orientation Catalogue – EOC‐2 and the new Hipparcos ones. The main steps of the method and the investigations of systematic errors in determined proper motions (the proper motion differences with respect to the Hipparcos values, the EOC‐2 ones and the new Hipparcos ones, as a function of α, δ, and magnitude) are presented here. A comparison of the four catalogues by pairs shows that there is no significant relationship between the differences of their μδ values and magnitudes and color indices of the common 807 stars. All catalogues have relatively small random and systematic errors which are close to each other. However, the comparison shows that our formal errors are too small. They are underestimated by a factor of nearly 1.7 (for EOC‐2, it is 2.0) if we take the new Hipparcos (or Hipparcos) data as reference (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Detecting Blood Laboratory Errors Using a Bayesian Network

To detect errors in blood laboratory results using a Bayesian network (BN), to compare results with an established method for detecting errors based on frequency patterns (LabRespond) and logistic regression model. In Experiment 1 and 2 using a sample of 5,800 observations from the National Health and Nutrition Examination Survey dataset, large, medium and small errors were randomly generated and introduced to liver enzymes (ALT, AST, and LDH) of the dataset. Experiment 1 examined systematic errors, while Experiment 2 investigated random errors. The outcome of interest was the correct detection of liver enzymes as "error" or "not error." With the BN, the outcome was predicted by exploiting probabilistic relationships among AST, ALT, LDH, and gender. In addition to AST, ALT, LDH, and gender, LabRespond required more information on related analytes to achieve optimal prediction. We assessed performance by examining the area under the receiver operating characteristics curves using a 10-fold cross validation method, as well as risk stratification tables. In Experiment 1, the BN significantly outperformed both LabRespond and logistic regression in detecting large (both at p < 0.001), medium (p = 0.01 and p < 0.001, respectively), and small (p = 0.03 and, p = 0.05, respectively) systematic errors. In Experiment 2, the BN performed significantly better than LabRespond and multinomial logistic regression in detecting large (p = 0.04 and p < 0.001, respectively) and medium (p = 0.05 and p < 0.001, respectively) random errors. A Bayesian network is better at detection and can detect errors with less information than existing automated models, suggesting that Bayesian model may be an effective means for reducing medical costs and improving patient safety.

BRORFELDE SCHMIDT CCD CATALOG

The Brorfelde Schmidt CCD Catalog (BSCC) contains about 13.7 million stars, north of +49 deg Declination with precise positions and V, R photometry. The catalog has been constructed from the reductions of 18,667 CCD frames observed with the Brorfelde Schmidt Telescope between 2000 and 2007. The Tycho-2 catalog was used for astrometric and photometric reference stars. Errors of individual positions are about 20 to 200 mas for stars in the R = 10 to 18 mag range. External comparisons with 2MASS and SDSS reveal possible small systematic errors in the BSCC of up to about 30 mas. The catalog is supplemented with J, H, and K_s magnitudes from the 2MASS catalog. The catalog data file (about 550 MB ASCII, compressed) will be made available at the Strasbourg Data Center (CDS).

Future balloon experiments for electron and positron measurements at high energy

A large interest has been triggered by the recent direct measurements of cosmic positrons and electrons. They include: the anomalous positron abundance reported by PAMELA; the spectral “feature” suggested by the analysis of the inclusive electron and positron data of the ATIC balloon experiment; the results of FERMI and H.E.S.S. experiments. Further accurate measurements, with smaller systematic errors, might clarify the present experimental scenario. While measurements of dipole asymmetries and of the electron spectrum above 1 TeV may require a space mission to provide a sufficient exposure, balloons can investigate the spectral shape below 1 TeV and contribute to the clarification of the, so-called, “ATIC anomaly”. A concise review will be presented of the main balloon missions that have been specifically designed to provide new electron measurements in the near future.

SU‐GG‐T‐326: Experimental Validation of a Scintillating Fiber Detector for Real‐Time Quality Control of MLC‐Driven Radiotherapy Treatment

Purpose: To validate a novel type of fluence monitoring detector based on the optical attenuation of scintillating fibers to be used for on‐line quality control of radiotherapy treatments. Method and Materials: 20 long scintillating fibers were aligned along the direction of motion of each of the 20 central pairs of leaves on a Varian Clinac iX MLC and coupled on both ends to a clear optical fiber to enable light collection. Following the theoretical model of scintillation collection based on optical attenuation previously developed, the central position (xc) and integral fluence. Φint) of various radiation fields were calculated and compared to the expected values as deduced from a radiographic film and a planar dose (PD) calculated from the treatment software. Results: The difference between the measured and calculated xc was within 2mm for more than 92% of the fields with a mean around 0.8mm. Of all these deviations, 93% can be explained by statistical variations (Poisson statistics). For Φint, the difference was less than 2% in 89% of the fields, with a mean around 0.9%. Although most of these discrepancies cannot be explained by statistical variations alone, they can be imputed on a small miss‐alignment of the fiber with the collimator leaves and small systematic errors with film processing and planar dose calculation. Nevertheless, any absolute displacement of MLC leaf pair of more than 3mm or any fluence variation over 3% can be detected by our system. Conclusion: This work validates the principle that a detector based on the optical attenuation of scintillating fibers can achieve real‐time quality control of a radiotherapy treatment with good precision. At the moment, the detection threshold for Φint is limited by the robustness of the fiber positioning system. This threshold is expected to fall below 2% with a more robust design.

Fundamental High-Pressure Calibration from All-Electron Quantum Monte Carlo Calculations

We develop an all-electron quantum Monte Carlo (QMC) method for solids that does not rely on pseudopotentials, and use it to construct a primary ultra-high-pressure calibration based on the equation of state of cubic boron nitride. We compute the static contribution to the free energy with the QMC method and obtain the phonon contribution from density functional theory, yielding a high-accuracy calibration up to 900 GPa usable directly in experiment. We compute the anharmonic Raman frequency shift with QMC simulations as a function of pressure and temperature, allowing optical pressure calibration. In contrast to present experimental approaches, small systematic errors in the theoretical EOS do not increase with pressure, and no extrapolation is needed. This all-electron method is applicable to first-row solids, providing a new reference for ab initio calculations of solids and benchmarks for pseudopotential accuracy.

Search for outbursts in the narrow 511-keV line from compact sources based on INTEGRAL data

We present the results of a systematic search for outbursts in the narrow positron annihilation line on various time scales (5x10^4 - 10^6 s) based on the SPI/INTEGRAL data obtained from 2003 to 2008. We show that no outbursts were detected with a statistical significance higher than ~6 sigma for any of the time scales considered over the entire period of observations. We also show that, given the large number of independent trials, all of the observed spikes could be associated with purely statistical flux fluctuations and, in part, with a small systematic prediction error of the telescope's instrumental background. Based on the exposure achieved in ~6 yr of INTEGRAL operation, we provide conservative upper limits on the rate of outbursts with a given duration and flux in different parts of the sky.

Human Sound-Localization Behavior Accounts for Ocular Drift

To generate an accurate saccade toward a sound in darkness requires a transformation of the head-centered sound location into an oculocentric motor command, which necessitates the use of an eye-in-head position signal. We tested whether this transformation uses a continuous representation of eye position by exploiting the property that the oculomotor neural integrator is leaky with a time constant of ∼20 s. Hence in complete darkness, the eyes tend to drift toward a neutral position. Alternatively, the spatial mapping stage could employ a sampled eye-position signal in which case drift will not be accounted for. Our data show that the sound location is accurately represented and that the transformation uses a dynamic eye-position signal. This signal, however, is slightly underestimated, leading to small systematic localization errors that tend to covary with the direction of eye position.

Three Novel Methods to Predict Traffic Time Series in Reconstructed State Spaces

This article proposes three novel methods—temporal confined (TC), spatiotemporal confined (STC) and spatial confined (SC)—to forecast the temporal evolution of traffic parameters. The fundamental rationales are to embed one-dimensional traffic time series into reconstructed state spaces and then to perform fuzzy reasoning to infer the future changes in traffic series. The TC, STC and SC methods respectively employ different fuzzy reasoning logics to select similar historical traffic trajectories. Theil inequality coefficient and its decomposed components are used to evaluate the predicting power and source of errors. Field observed one-minute traffic counts are used to test the predicting power. The results show that overall prediction accuracies for the three methods are satisfactorily high with small systematic errors and little deviation from the observed data. It suggests that the proposed three methods can be used to capture and forecast the short-term (e.g., one-minute) temporal evolution of traffic parameters.

Moving nonrelativistic QCD for heavy-to-light form factors on the lattice

We formulate nonrelativistic quantum chromodynamics (NRQCD) on a lattice which is boosted relative to the usual discretization frame. Moving NRQCD allows us to treat the momentum for the heavy quark arising from the frame choice exactly. We derive moving NRQCD through $\mathcal{O}(1/{m}^{2},{v}_{\mathrm{rel}}^{4})$, as accurate as the NRQCD action in present use, both in the continuum and on the lattice with $\mathcal{O}({a}^{4})$ improvements. We have carried out extensive tests of the formalism through calculations of two-point correlators for both heavy-heavy (bottomonium) and heavy-light (${B}_{s}$) mesons in $2+1$ flavor lattice QCD and obtained nonperturbative determinations of energy shift and external momentum renormalization. Comparison to perturbation theory at $\mathcal{O}({\ensuremath{\alpha}}_{s})$ is also made. The results demonstrate the effectiveness of moving NRQCD. In particular we show that the decay constants of heavy-light and heavy-heavy mesons can be calculated with small systematic errors up to much larger momenta than with standard NRQCD.

An Assessment of Action Levels in Imaging Strategies in Head and Neck Cancer using TomoTherapy. Are Our Margins Adequate in the Absence of Image Guidance?

Aims To assess the effectiveness of different on-treatment correction strategies on set-up accuracy in patients with head and neck cancer (HNC) treated on a TomoTherapy HiArt™ system. To assess the adequacy of clinical target volume (CTV) to planning target volume (PTV) treatment planning margins when treating with intensity-modulated radiotherapy without daily image guidance. Materials and methods The set-up accuracy measured by daily online volumetric imaging was retrospectively reviewed for the first 15 patients with HNC treated on the TomoTherapy unit at Addenbrooke's Hospital. For each fraction, megavoltage computed tomography was carried out, any discrepancy from the planning scan was noted, and corrected, before treatment. These data were used to evaluate imaging correction protocols using three different action levels. The first three fractions were imaged and used to correct for systematic error, using a 5 mm action level (5 mmAL), a 3 mm action level (3 mmAL), and no action level (NAL). All imaging strategies were applied, to assess the number of fractions that would potentially have exceeded a 5 and 3 mm margin. Systematic and random errors were calculated for the population, assuming the NAL protocol had been applied, and minimum CTV–PTV margins, required to allow for errors attributable only to set-up, were calculated using van Herk's formula. Results In total, 490 fractions were analysed. Using a 5 mmAL imaging protocol, potentially 198/490 fractions (40%) were outside a 5 mm CTV–PTV margin and 400/490 (82%) were outside a 3 mm margin. Using a 3 mmAL imaging protocol, potentially 67/490 fractions (14%) were outside a 5 mm CTV–PTV margin and 253/490 (52%) were outside a 3 mm margin. A small systematic error was identified in the system; once corrected this would improve these results. Using the NAL imaging protocol, potentially 31/490 fractions (6%) were outside a 5 mm CTV–PTV margin and 143/490 fractions (29%) were outside a 3 mm margin. Estimated minimum CTV–PTV margins to account only for set-up errors, with three-fraction image-guided radiotherapy and a NAL protocol, were 2.8, 3.1 and 4.1 mm in the mediolateral, superior–inferior and anterior–posterior directions, respectively. Conclusion Reducing the action level at which the systematic error is corrected improves the probability of treatment delivery accuracy. Using the NAL correction protocol reduces the number of fractions that have set-up displacements outside a 5 mm CTV–PTV margin. Although a 5 mm margin is probably sufficient for standard HNC radiotherapy, change to a 3 mm margin is not favoured at our centre without access to daily image-guided radiotherapy.

A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment

We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions ( ν μ n→ μ - p and bar{ν }_{μ}ptoμ+n ) using a set of experimental data collected by the NOMAD Collaboration. We have performed measurements of the cross-section of these processes on a nuclear target (mainly carbon) normalizing it to the total ν μ ( bar{ν}_{μ} ) charged-current cross section. The results for the flux-averaged QEL cross sections in the (anti)neutrino energy interval 3-100 GeV are < σ_{qel}rangle_{ν_{μ}}=(0.92±0.02(stat)±0.06(syst))×10^{-38} cm2 and <σ_{qel}rangle_{bar{ν}_{μ}}=(0.81±0.05(stat)±0.09(syst))×10^{-38} cm2 for neutrino and antineutrino, respectively. The axial mass parameter M A was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is M A =1.05±0.02(stat)±0.06(syst) GeV. It is consistent with the axial mass values recalculated from the antineutrino cross section and extracted from the pure Q 2 shape analysis of the high purity sample of ν μ quasi-elastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured M A is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of M A is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on M A , these results are compatible with the more precise NOMAD value.

Reduction of systematic errors in regional climate simulations of the summer monsoon over East Asia and the western North Pacific by applying the spectral nudging technique

In this study, the systematic errors in regional climate simulation of 28‐year summer monsoon over East Asia and the western North Pacific (WNP) and the impact of the spectral nudging technique (SNT) on the reduction of the systematic errors are investigated. The experiment in which the SNT is not applied (the CLT run) has large systematic errors in seasonal mean climatology such as overestimated precipitation, weakened subtropical high, and enhanced low‐level southwesterly over the subtropical WNP, while in the experiment using the SNT (the SP run) considerably smaller systematic errors are resulted. In the CTL run, the systematic error of simulated precipitation over the ocean increases significantly after mid‐June, since the CTL run cannot reproduce the principal intraseasonal variation of summer monsoon precipitation. The SP run can appropriately capture the spatial distribution as well as temporal variation of the principal empirical orthogonal function mode, and therefore, the systematic error over the ocean does not increase after mid‐June. The systematic error of simulated precipitation over the subtropical WNP in the CTL run results from the unreasonable positive feedback between precipitation and surface latent heat flux induced by the warm sea surface temperature anomaly. Since the SNT plays a role in decreasing the positive feedback by improving monsoon circulations, the SP run can considerably reduce the systematic errors of simulated precipitation as well as atmospheric fields over the subtropical WNP region.

Reliability and accuracy of cone-beam computed tomography dental measurements

Dental measurements are an integral part of the orthodontic records necessary for proper diagnosis and treatment planning. In this study, we investigated the reliability and accuracy of dental measurements made on cone-beam computed tomography (CBCT) reconstructions. Thirty human skulls were scanned with dental CBCT, and 3-dimensional reconstructions of the dentitions were generated. Ten measurements (overbite, overjet, maxillary and mandibular intermolar and intercanine widths, arch length available, and arch length required) were made directly on the dentitions of the skulls with a high-precision digital caliper and on the digital reconstructions with commercially available software. Reliability and accuracy were assessed by using intraclass correlation and paired Student t tests. A P value of < or = 0.05 was used to assign statistical significance. Both the CBCT and the caliper measurements were highly reliable (r >0.90). The CBCT measurements tended to slightly underestimate the anatomic truth. This was statistically significant only for compounded measurements. Dental measurements from CBCT volumes can be used for quantitative analysis. With the CBCT images, we found a small systematic error, which became statistically significant only when combining several measurements. An adjustment for this error allows for improved accuracy.

In-Use Comparison of Blood Pressure Measurements from an Automated Blood Pressure Instrument with Those from a Mercury Sphygmomanometer

In addition to its ease of use and degree of independence from the subjectivity inherent in measurements made with the mercury sphygmomanometer (HgS), automated blood pressure measurement instruments (ABPMI) obviate the use of mercury-containing instrumentation and the attendant environmental issues. Thus, they have been widely used in healthcare facilities worldwide. Most evaluations of ABPMI have focused on their compliance with established international protocols, and there has been a paucity of studies examining their performance in actual use in healthcare facilities. The purpose of this study was to evaluate the ABPMI used in our institution--a large, urban, tertiary-care teaching hospital in the northeastern United States--under routine conditions. This device, the Dinamap ProCare 400 Monitor, was compared to HgS (considered the "gold standard" for non-invasive blood pressure measurement) with respect to key analytical variables, i.e., precision of measurements and correlation within a large (n=300) sample of patients. Several sources of observer bias with HgS were detected. Precision varied among parameter (systolic blood pressure [SBP]; diastolic blood pressure [DBP]; and mean arterial pressure [MAP]) and level (normotensive, moderately hypertensive, and severely hypertensive). Correlation and regression suggested a strong association between the methods and Bland-Altman analysis indicated an acceptably small systematic error (bias) but greater random error than that demonstrated by previous evaluations with international test protocols. We recommend that healthcare facilities evaluate ABPMI under actual conditions and that formal protocols be established for these evaluations under routine conditions of patient care.

On site calibration for new fluorescence detectors of the telescope array experiment

The Telescope Array experiment is searching for the origin of ultra-high energy cosmic rays using a ground array of particle detectors and three fluorescence telescope stations. The precise calibration of the fluorescence detectors is important for small systematic errors in shower reconstruction. This paper details the process of calibrating cameras for two of the fluorescence telescope stations. This paper provides the operational results of these camera calibrations.