OP Data Research Articles

A Step Toward Deep Online Aggregation

For exploratory data analysis, it is often desirable to know what answers you are likely to get before actually obtaining those answers. This can potentially be achieved by designing systems to offer the estimates of a data operation result-say op(data)-earlier in the process based on partial data processing. Those estimates continuously refine as more data is processed and finally converge to the exact answer. Unfortunately, the existing techniques-called Online Aggregation (OLA)-are limited to a single operation; that is, we cannot obtain the estimates for op(op(data)) or op(...(op(data))). If this Deep OLA becomes possible, data analysts will be able to explore data more interactively using complex cascade operations. In this work, we take a step toward Deep OLA with evolving data frames (edf), a novel data model to offer OLA for nested ops-op(...(op(data)))-by representing an evolving structured data (with converging estimates) that is closed under set operations. That is, op(edf) produces yet another edf; thus, we can freely apply successive operations to edf and obtain an OLA output for each op. We evaluate its viability with Wake, an edf-based OLA system, by examining against state-of-the-art OLA and non-OLA systems. In our experiments on TPC-H dataset, Wake produces its first estimates 4.93× faster (median)-with 1.3× median slowdown for exact answers-compared to conventional systems. Besides its generality, Wake is also 1.92× faster (median) than existing OLA systems in producing estimates of under 1% relative errors.

RWD152 Real-World Evidence on the Use of Ecmo in Hospitalized COVID-19 Patients: Results from a Linked Closed and Open Claims Database in the US

To describe the use of extracorporeal membrane oxygenation (ECMO) among hospitalized coronavirus disease 2019 (H-COVID-19) patients in a linked closed claims (CC) and open claims (OC) database. This analysis identified H-COVID-19 patients between April 2020 (Q2 2020) and June 2022 (Q2 2022) in CHRONOS, a linked CC and OC database. The index event was the date of hospitalization, defined as an inpatient claim within 21 days of a COVID-19 diagnosis in the CC. The occurrence of ECMO 30 days after index was identified using CC data alone and then CC and OP data in combination to assess missing data. Study exclusions included patients under the age of 18, a first COVID-19 diagnosis that did not result in hospitalization, and less than 12-months of continuous enrollment in the CC before index. Study criteria were defined by the presence of an ICD-10-CM, ICD-10-PCS, or CPT code on a claim. Results are reported as percentages and 95% confidence intervals. Of 321,687 patients with H-COVID-19, the mean age was 50.1 (SD:12.8) with the highest proportion of hospitalizations occurring in Q3 2021 (19.4%). Overall, 0.50% (0.48%-0.52%) of patients in the CC data received ECMO, increasing to 0.61% (0.58%-0.64%) with the inclusion of OC data. The use of ECMO to treat H-COVID-19 patients decreased between Q2 2021 and Q2 2022, with the highest rates occurring in Q2 of 2020 (0.78%) and Q2 2021 (0.80%). The addition of OC data increased rates to 1.12% and 0.89% in Q2 of 2020 and Q2 2021. Although use of ECMO decreased in the later months of the pandemic, it represents a substantial burden. The current analysis demonstrates that CC data, often sourced from payers, may underestimate the use of ECMO in real-world settings. Opportunities exist to mitigate issues of missing data by linking CC, OC, and other real-world data sources.

A Need to Revise Stellar Opacities from Asteroseismology of δ Scuti Stars

We construct seismic models of the four double-mode radial δ Scuti stars adopting opacities from three databases: OPAL, OP, and OPLIB. The aim is to find the models that fit the observed frequencies of the two radial modes and have the effective temperature and luminosity consistent with the observed values. Using the Bayesian analysis based on Monte Carlo simulations, we obtain that only the OPAL seismic models are caught within the observed error box in the H-R diagram. Seismic models computed with the OP and OPLIB data are much cooler and less luminous. By including the relative amplitude of the bolometric flux variations (the so-called parameter f) into these simulations, we constrain the efficiency of convection in the envelopes, described by the mixing-length parameter α MLT. We get α MLT ≈ 0.5 for BP Pegasi, AE Ursa Majoris, and RV Arietis (Population I stars) and α MLT ≈ 1.0 for SX Phoenicis (Population II star). For all the stars, overshooting from the convective core seems inefficient. A similar effect of opacity should occur also for classical Cepheids or RR Lyr stars that are used as standard candles to measure the universe.

Asteroseismology of the double-radial mode δ Scuti star BP Pegasi

ABSTRACT Using the All-Sky Automated Survey data, we determine the pulsational frequencies of the high-amplitude δ Scuti star BP Pegasi. The analysis revealed only the two known, independent frequencies that we use to perform the seismic analysis of the star. On the basis of multicolour Strömgren photometry, we independently find that both frequencies can only be associated with radial modes which, according to the frequency ratio, are fundamental and first overtone modes. The models fitting the two frequencies depend strongly on the opacity data. For low values of the mixing-length parameter αMLT ≈ 0.5, only the OPAL seismic models in the post-main-sequence phase of evolution are caught within the observed error box. Seismic models computed with the OP and OPLIB data are much less luminous and cooler. They can only reach the error box if we increase the convection efficiency to at least αMLT = 2.0. Then, including the non-adiabatic parameter f into our seismic modelling, we constrain the value of αMLT. Computing an extensive grid of seismic OPAL models and employing Monte Carlo-based Bayesian analysis, we obtain constraints on various parameters. In particular, the efficiency of envelope convection can be parametrized by αMLT ∈ (0.5, 1.0), depending on the atmospheric microturbulent velocity that amounts to ξt = 4 or 8 km s−1.

Which parameters are relevant in sagittal balance analysis of the cervical spine? A literature review.

Cervical spine is part of the spine with the most mobility in the sagittal plane. It is important for surgeons to have reliable, simple and reproducible parameters to analyse the cervical. This study is a systematic review and a critique of current parameters to help improve the study of cervical spinal balance. We conducted a systematic search of PUBMED/MEDLINE for literature published since January 2014. Only studies written in English and containing abstracts were considered for inclusion. The search performed was: «C7 slope» OR «T1 slope» OR «C2C7 offset» OR «C2C7 lordosis» OR «cervical SVA (sagittal vertical axis)» OR «TIA (thoracic inlet angle)» (Lee et al., J Spinal Disord Tech 25(2):E41-E47, 2012) OR «SCA (spino-cranial angle)». Exclusion criteria were purely post-operative and cadaveric analysis, studies performed with CT scan or MRI, studies on adolescent idiopathic scoliosis, traumatology studies and no standing analysis of the cervical spine. Relevance was confirmed by investigators if cervical parameters was a major criteria of the study. 138 articles were found by the electronic search. After complete evaluation 20 articles were selected. The large majority of papers used the same parameters C2_C7 lordosis, C2-C7 SVA, T1 slope or C7 slope and T1 slope/cervical lordosis mismatch. Janusz reported a new parameter using a retrospective cohort of patient with cervical radiculopathy: the TIA (thoracic inlet angle). Le Huec reported an other new parameter based on a prospective study of asymptomatic volunteer: the spino-cranial angle (SCA). This parameter is highly correlated with the C7 slope and the cervical lordosis. Other studies reported parameters that are more global balance analysis including the cervical spine than cervical spine balance itself. The most important parameters to analyse the cervical sagittal balance according to the literature available today for good clinical outcomes are the following: C7 or T1 slope, average value 20°, must not be higher than 40°. cSVA must not be less than 40°C (mean value 20mm). SCA (spine cranial angle) must stay in a norm (83°±9°). Future studies should focus on those three parameters to analyse and compare pre and post op data and to correlate the results with the quality of life improvement.

Impaired Vestibular Function After Cochlear Implantation in Children: Role of Static Posturography.

To identify vestibular dysfunction in children after cochlear implant surgery and to study the utility of static posturography in evaluating vestibular function in children. A prospective study was carried out on 25 children between 2 and 7years of age with sensorineural hearing loss with no overt vestibular dysfunction. All children underwent static posturography using Synapsis Posturographic System (SPS) software (Version 3.0, REV C) using a static platform with foam. The centre of pressure (COP) shift was recorded as statokinesiogram on the software and the mean vestibular, visual and somesthetic scores were obtained. Cochlear implantation (CI) surgery was done with insertion of Med-El Pulsar standard cochlear implant with 12 twin electrodes. Children were evaluated again after 4weeks of CI surgery (2weeks after switch on) with static posturography on the same SPS software. The scores obtained were compared with pre op value and data analyzed statistically by paired t tests on SPSS 18 software. The mean age was 4.6years with range 2-7years. All the children in the study were able to complete the test with no difficulty and the mean time required for each child was 10.2min. The mean pre op somesthetic score was 95.16 (SD 1.52) and post op score was 94.06 (SD 1.79). The mean pre op visual score was 86.64 (SD 2.24) and post op score was 82.55 (2.89). The mean pre op vestibular score was 84.11 (SD 2.20) and post op score was 73.66 (SD 4.25). Correlation and statistical analysis of the pre and post values of each score revealed statistically significant reduction in vestibular scores post CI. The vestibular system is at high risk of injury leading to vestibular dysfunction in children during CI. Our study found the static posturography as a simple, fast and efficient tool to screen children for vestibular dysfunction post CI. Identifying the dysfunction early can help in initiating early rehabilitation measures.

OPACITY CALCULATIONS FOR SOLAR MIXTURES

The OPAS opacity model has been used to calculate the radiative opacity of stellar plasmas in local thermodynamic equilibrium. According to the recent chemical composition revision of the solar photosphere, opacities have been computed for various hydrogen and metallic element mass fractions. Calculations have been performed toward solar interior modeling for temperatures between and , and for electron densities between and . We discuss possible sources of uncertainty in the calculations. We also compare Rosseland opacities to OPAL and OP data.

Wider pulsation instability regions forβCephei and SPB stars calculated using new Los Alamos opacities

Aims. Our goal is to test the newly developed OPLIB opacity tables from Los Alamos National Laboratory and check their influence on the pulsation properties of B-type stars.Methods. We calculated models using MESA and Dziembowski codes for stellar evolution and linear, nonadiabatic pulsations, respectively. We derived the instability domains of β Cephei and SPB-types for different opacity tables OPLIB, OP, and OPAL.Results. The new OPLIB opacities have the highest Rosseland mean opacity coefficient near the so-called Z -bump. Therefore, the OPLIB instability domains are wider than in the case of OP and OPAL data.

Asteroseismology with the new opacity bump at log T ≈ 5.06

AbstractAlthough the κ mechanism of pulsations is known for early-type stars, opacities and the equation of state are still uncertain. Stellar models calculated for the OP data implemented with the new Kurucz opacities at log T < 5.2 were investigated for different chemical compositions of elements. The additional metallic opacity bump at log T ≈ 5.06 that occurs in the Kurucz data changes markedly the oscillation spectra of unstable modes. Basic properties of the new opacity bump and examples of seismic models are shown. B-type stars observed in the Galaxy, LMC and SMC were considered. The problem was studied using Dziembowski's computing codes for linear, non-adiabatic and non-radial oscillations.

EURO-SCORING FOR RISK STRATIFICATION IN CABG SURGERY - 10 YEARS EXPERIENCE

Aim of the study was to evaluate patients pre operatively with Euroscoring System to judge the end point, hospital mortality in CABG done in last ten years by a single surgeon. From June 1989 to June 1999 the data of 262 cases of CABG done was collected on the data sheet each case was scored pre operatively with Euroscoring System. The different groups were made from this system, Group 1 Score 0-1, Group 2 Score 3- 4, Group 3 Score 5-6, Group 4 Score 7-8, Group 5 > 9, Another Grouping was Group 1 score 0-5, and Group 2 score 6-10 and Group 3 score 11-15. Pre op data was collected and analyzed by SPSS Version 7.5, The End point was hospital mortality. In this group of 262 patients, the age range was 25-77 with the mean 52.41 years, 248 (94.7%) were male and 14 (5.3%) were female. In this whole cohort of pas patients 227 (86.6%) were having stable angina pectoris and 35 (13.4%) were having unstable angina. Pre op angina status was Class I in 5 (1.9%), Class II 88 (33,6%), Class III 132 (50.4%) and Class IV were 37 (14.1%). There were 116 (44.3%) hypertensive, 56 (21.4%) were diabetics and 9 (3.4%) were obese. Recent myocardial Infarction was there in 9 (14%) of cases, the old non Q- wave infarction was present in 18 (6.9%) of cases and Q- wave infarction was present in 42 (16%) of cases. Pre op Ejection fraction was good in (EF>50%) in 204 (77.9%) cases, Fair EF 30-49%) in 50 (19.1%) cases, poor EF 9) the mortality was 60%. The Euroscore from 0-5 was having 6.1% mortality, the score from 6-10 was having 20% and the score from 11-15 was having 80% mortality. On Logistic regression overall predictive accuracy of Euroscoring is very good (90%), Predictive accuracy, 37% of deaths could be explained on the existing variables positive predictive value is 19.05% and negative predictive value is 99.17%. The predictive accuracy of Euroscoring changes with various risk groups. In low risk Groups (Score 0-5) and (Score 6-10) Euroscore predicts survival more accurately. In high risk Group (11-15) Euroscoring better predicts mortality rather than survival. The factors included in permutations of Euroscore explain only 37% of the observed mortality. It is noted that the observed mortality is consistently higher than that predicted by logistic regression. Euroscoring is a good tool of risk stratification to predict the out come but not ideally suited to our clinical circumstances. Though we have documented an overall predictive accuracy of 92%, it is limited in its usefulness because it does not take into consideration certain risk factors found to be important in our patient population. In addition, the relative weight assigned to various risk factors in scoring needs to be readjusted for our patient population in the light of observations made on our patient population. There is a need to develop a scoring system of our own which could be used for better prediction of outcomes in our clinical circumstances

Practice Patterns and Opening Pressure Measurements Using Fluoroscopically Guided Lumbar Puncture

Evidenced-based protocols for fluoroscopically guided LP do not exist. This study analyzed the fluoroscopically guided LP techniques currently used by practicing neuroradiologists. An anonymous Web-based survey was e-mailed to members of ASNR. The results were compiled and tabulated on a spreadsheet. A total of 577 neuroradiologists completed the survey. Most neuroradiologists perform fluoroscopically guided LPs with the patient in the prone position by using a 22-ga needle at the L2-L3 or L3-L4 intervertebral space. The OP measurement technique is quite variable. Only a minority of patients are rotated to the left LD position for OP measurement. Most neuroradiologists observe patients for 1-2 hours after the procedure and require strict bed rest. Most neuroradiologists have similar protocols for thecal sac puncture. Normative adult OP data exist only for the LD position, and the accuracy of prone OP measurements is not known. We found that the OP measurement technique is not consistent and a standard protocol is warranted.

Constraints on opacities from complex asteroseismology of B-type pulsators: the β Cephei star θ Ophiuchi

We present results of a comprehensive asteroseismic modelling of the β Cephei variable θ Ophiuchi. We call these studies complex asteroseismology because our goal is to reproduce both pulsational frequencies and corresponding values of a complex, non-adiabatic parameter, f, defined by the radiative flux perturbation. To this end, we apply the method of simultaneous determination of the spherical harmonic degree, ℓ, of excited pulsational mode and the corresponding non-adiabatic f parameter from combined multicolour photometry and radial velocity data. Using both the OP and OPAL opacity data, we find a family of seismic models which reproduce the radial and dipole centroid mode frequencies, as well as the f parameter associated with the radial mode. Adding the non-adiabatic parameter to seismic modelling of the B-type main-sequence pulsators yields very strong constraints on stellar opacities. In particular, only with one source of opacities it is possible to agree the empirical values of f with their theoretical counterparts. Our results for θ Oph point substantially to preference for the OPAL data.

NLPCA as a diagnostic tool for control valve stiction

A significant number of control loops in process plants perform poorly due to control valve stiction. Developing a method to detect valve stiction in the early phase is imperative to avoid major disruptions to the plant operations. Nonlinear principal component analysis (NLPCA), widely known for its capability in unravelling nonlinear correlations in process data, is extended in this paper to diagnose control valve stiction problems. The present work is based on distinguishing the difference between the shapes of the signals caused by stiction and other sources, and utilizes the operating data of controlled variable-controller output ( pv– op). The structure of pv– op data used in this work is of sufficiently low dimension such that the NLPCA’s output allows the usage of simple mathematical tests in quantifying the nonlinear behavior of the loop. It is shown that if the underlying structure of pv– op data is linear, the NLPCA output generally approximates to a straight line with a regression coefficient ( R 2) greater than 0.8, otherwise there is a possibility of presence of nonlinearity or non-Gaussianity. The presence of stiction is then detected via a new and simple NLPCA curvature index, I NC . Results from simulated and real industrial case studies show that NLPCA is a very promising tool for detecting valve stiction.

Stiction Identification in Nonlinear Process Control Loops

Abstract Abstract Nearly 20–30% of all process control loops oscillate due to stiction and lead to loss of productivity. Thus, the detection and quantification of stiction in control valves using just the raw operating data is an important component of any automated controller performance monitoring application. Many techniques have been proposed for the detection and quantification of stiction. Pattern based identification approaches use unique shapes of the PV and OP data to identify stiction. Other approaches that include some measure of nonlinearity index have also been used to identify stiction. A solution technique for stiction detection in nonlinear processes with known process models is also available. In this paper, one possible approach to detect stiction in nonlinear process control loops with unknown process models is discussed.

The two hybrid B-type pulsators: ν Eridani and 12 Lacertae

A B ST R A C T Therich oscillation spectra determ ined forthe two stars, � Eridaniand 12 Lacertae, present an interesting challenge to stellar m odelling.The stars are hybrid objects showinganum berofm odesatfrequenciestypicalforCep starsbutalsoonem odeat frequencytypicalforSPB stars.W econstructseism icm odelsofthesestarsconsidering uncertainties in opacity and elem ent distribution.W e also present estim ate ofthe interiorrotation rateand addressthem atterofm odeexcitation. W euseboth theOP and OPAL opacity data andnd signicantdierencein the results.Uncertainty in thesedatarem ainsam ajorobstaclein precisem odelling ofthe objectsand,in particular,in estim ating the overshooting distance.W end evidence forsignicantrotation rateincreasebetween envelopeand corein thetwo stars. Instability oflow-frequency g-m odeswasfound in seism ic m odelsofEribuilt with the OP data,but at frequencies higher than those m easured in the star.No such instability was found in m odels of12 Lac.W e do not have yet a satisfactory explanation for low frequency m odes.Som e enhancem ent ofopacity in the driving zoneisrequired butwearguethatitcannotbeachieved by theiron accum ulation,as ithasbeen proposed.

Updated Opacity Project radiative accelerations

Updated data for the calculation of radiative accelerations, grad, referred to as OP 2005, have been made generally available on the Web. They differ from the earlier 1997 OP data mainly in the inclusion of contributions from inner-shell processes. The frequency resolution used for OP 2005 is shown to be satisfactory except for extreme cases of low concentrations and low densities. The 2005 data are in reasonably good agreement with results from OPAL, given by Richer et al. in graphical form, for a model with T eff = 10 4 and log (R) =− 3. They are in less good agreement with OPAL results of Turcotte et al. for the solar radiative interior.

A time series investigation of the oxygen isotopic composition of dissolved inorganic phosphate in Monterey Bay, California

We present a 2-yr time series of the oxygen isotopic composition of dissolved inorganic phosphate (d18Op )i n Monterey Bay, California. d18Op can serve as a proxy for phosphate utilization because its approach toward isotopic equilibrium is a function of the degree of biological phosphate cycling. When phosphate is extensively cycled by the biological community in the euphotic zone, the d18Op approaches isotopic equilibrium with surrounding water. Our results indicate that d18Op in the upper water column is consistently out of isotopic equilibrium with respect to seawater and fluctuates between the equilibrium value and the isotopic signatures of phosphate sources. This suggests that either phosphate is not extensively utilized or that the input of new phosphate to the bay exceeds the requirements of the biological community. d18Op is variable and linked to episodic upwelling events and the biotic response to these events. The greatest percent of phosphate oxygen exchange, and thus the greatest phosphate utilization relative to input, occurs at the locus of upwelling (Sta. M1), followed by the offshore (M2) and nearshore (C1) stations, respectively. During the highly productive upwelling season, phosphate turnover is greater than in the winter. Episodes of higher phosphate turnover, as indicated by peaks in d 18 Op, occur simultaneously throughout the upper 200 m of the water column and at all three stations, indicating that these events affect the bay on a large scale. d 18 Op data also suggest that deep water (.500 m) may be a source of phosphate to the euphotic zone in Monterey Bay.

The ΔKeff-concept: A unique and complete description of fatigue crack propagation

Fatigue crack propagation (FCP) rates were obtained by R-constant (ASTM E647) and K max-constant test methods for a spectrum of R-ratios and K max values on the Ni-base alloy Nicrofer 5219 Nb (annealed) and AI 7075-T7351. Furthermore, non-propagation conditions ΔK th as a limit for the FCP regime, were determined for these materials. The partitioning point K op dividing ΔK into ΔK eff had been experimentally determined for Nicrofer 5219 Nb (annealed) and Al 7475-T7351 [1]. The K op was expressed as a polynomial equation of R-ratio and K max. These K op data were applied to the FCP data of Nicrofer 5219 Nb (annealed) and Al 7075-T7351. It is shown that the ΔK eff concept is a unique and complete description of FCP. Even the wedging action of the wake zone associated with a fatigue crack, which frequently occurs when testing at low R-ratios, is easily accounted for by the ΔK eff concept.

Fatigue crack closure in the near-threshold level in a high-strength low-alloy structural steel

Fatigue crack closure is measured by a back face strain gauge for a high-strength structural steel SANH-55. In the near-threshold region, K op data are found to be consistent with either oxide-induced closure or roughness-induced closure. In the linear regime of the Paris plot, K op is roughly constant, independent of ΔK and the R-ratio. The contribution of the oxide-induced crack closure can be deleted by K max constant and ΔK decreasing tests in near threshold, in which case plasticity-induced crack closure plays an important role.

K-matrix analysis of the low-energy data for K −p and K 2op reactions

A nine-parameter zero-range K-matrix S-wave fit is made to the available experimental data for K −p and K 2 op reactions below 280 MeV/ c. A unique solution is obtained and compared with the effective-range solution obtained by Kim. It is found that both solutions give good agreement with the data for processes involving only the K N and Σπ channels, but that for processes involving the Λπ channel the present fit improves on the effective-range fit over the momentum range 0–280 MeV/ c. The scattering lengths corresponding to the K-matrix solution are given and compared with those obtained in previous analyses. The K-matrix solution is used to compute the unphysical region contribution to KN forward dispersion relations and the ΛKN and ΣKN coupling constants are calculated. In addition a multichannel analysis of the K −p and K 2 op data below 400 MeV/ c is performed with the inclusion of K N isospin one P-wave amplitudes. In the region up to 400 MeV/ c the P 1 2 and P 3 2 waves are found to be equally important. Argand plots of the various K N partial-wave amplitudes are given.