Best-fit Polynomial Research Articles

Optimization of the Product Yields of the Pyrolysis of Palm Kernel Shell in a Fixed-Bed Reactor Using Response Surface Methodology (RSM)

Pyrolysis is a method used for the thermochemical conversion of biomass and agro wastes into three major by-products namely, biochar, bio-oil, and biogas in the absence of oxygen. Global waste generation is increasing at an alarming rate. Palm kernel shell (PKS) is among the palm wastes accumulating in many palm oil mills around the globe with the attendant problems in waste management. The utilization of coal for energy generation is more expensive and not environmentally friendly. Bio-oil refineries and industries require the utilization of minimum resources (input) to achieve optimal response (output) in the production process. However, more than 30% of the energy content derivation from the pyrolysis process is wasted due to nonoptimization of the process parameters. This study investigated the optimization of the product yields of the pyrolysis of PKS in a fixed-bed batch reactor using response surface methodology (RSM). Masses of 1 kg, 2 kg, and 3 kg were pyrolyzed in batches at process temperature variations of 200 OC, 300 OC, 400 OC, and 500 OC. Design Expert 12 software (Version 12.0.3.0 Stat-Ease Inc. MN, USA) and Analysis of Variance (ANOVA) were used for the statistical analysis. Lack-of-fit, adjusted, and predicted multiple correlation coefficients and coefficient of variation of the different polynomial models were compared to select the best-fitting polynomial model. The optimal feedstock parameters were 2.66 kg of PKS and 410.0 OC process temperature. The predicted results were 0.986 kg of biochar, 1.205 kg of bio-oil, 0.481 kg of biogas, 1116.5 cm3 of bio-oil, and 140.6 minutes. The experimental results were 0.894 kg of biochar, 1.316 kg of bio-oil, 0.498 kg of biogas, 1208.9 cm3 of bio-oil, and at 162.8 minutes through validation. The validated quadratic model was suitable for the optimization and RSM is a numerical, statistical, and mathematical tool for modeling and optimization of the pyrolysis process in a fixed-bed batch reactor.

Enabling attractive-repulsive potentials in binary-collision-approximation monte-carlo codes for ion-surface interactions

Binary Collision Approximation (BCA) codes for ion-material interactions, such as SRIM, Tridyn, F-TRIDYN, and SDtrimSP, have historically been limited to screened Coulomb potentials even at low energies due to the difficulty in numerically solving the Distance of Closest Approach (DOCA) problem for attractive-repulsive potentials. Techniques such as direct n-body simulation or modifications to Newton’s method are either prohibitively costly or not guaranteed to work for all potentials. Advanced rootfinding techniques, such as companion matrix solvers, offer a solution. For many attractive-repulsive potentials, however, a companion matrix cannot be used directly, because there is no way to put the associated functions into a monomial basis form. A complementary technique is proxy rootfinding—by finding the best-fit polynomial approximant of a function, the zeros of the approximant can be guaranteed to be close to the zeros of the function. Using the Chebyshev basis and grid offers additional guarantees with regards to the quality of the approximation, the speed of convergence, and the avoidance of Runge’s phenomenon. By finding Chebyshev interpolants and using the Chebyshev-Frobenius companion matrix, the zeros of any real function on a bounded domain can be found. Here we show that using an Adaptive Chebyshev Proxy Rootfinder with Automatic Subdivision (ACPRAS) with appropriate scaling functions, numerical issues presented by attractive-repulsive potentials, including those of scale, can be handled. Using these techniques, we show that it is possible to include any physically reasonable interatomic potential in a BCA code, and to guarantee correctness of the resulting scattering angle calculations.

Substrate oxidation during exercise in childhood acute lymphoblastic leukemia survivors

Children with acute lymphoblastic leukemia (ALL) are at high risk of developing long-term cardiometabolic complications during their survivorship. Maximal fat oxidation (MFO) is a marker during exercise of cardiometabolic health, and is associated with metabolic risk factors. Our aim was to characterize the carbohydrate and fat oxidation during exercise in childhood ALL survivors. Indirect calorimetry was measured in 250 childhood ALL survivors to quantify substrate oxidation rates during a cardiopulmonary exercise test. A best-fit third-order polynomial curve was computed for fat oxidation rate (mg/min) against exercise intensity (O2peak) and was used to determine the MFO and the peak fat oxidation (Fatmax). The crossover point was also identified. Differences between prognostic risk groups were assessed (ie, standard risk [SR], high risk with and without cardio-protective agent dexrazoxane [HR + DEX and HR]). MFO, Fatmax and crossover point were not different between the groups (p = .078; p = .765; p = .726). Fatmax and crossover point were achieved at low exercise intensities. A higher MFO was achieved by men in the SR group (287.8 ± 111.2 mg/min) compared to those in HR + DEX (239.8 ± 97.0 mg/min) and HR groups (229.3 ± 98.9 mg/min) (p = .04). Childhood ALL survivors have low fat oxidation during exercise and oxidize carbohydrates at low exercise intensities, independently of the cumulative doses of doxorubicin they received. These findings alert clinicians on the long-term impact of cancer treatments on childhood ALL survivors’ substrate oxidation.

O-149 Endometrial thickness as a predictor of live birth and perinatal outcomes following oocyte donation

Abstract Study question Does endometrial thickness (EMT) predict the occurrence of live birth following oocyte donation? Summary answer Our study found that EMT is predictive of live birth in oocyte donation. What is known already EMT is a widely used surrogate marker of endometrial receptivity and is believed to be associated with in vitro fertilization pregnancy outcomes. However, the evidence thus far is mixed, with many studies (and even meta-analyses) suggesting that EMT may have little/no predictive value. One potential reason for the heterogeneity in results may be that most studies assessed mostly fresh autologous embryo transfers, without accounting for embryo quality nor the effect exogenous ovarian stimulation may have on endometrial receptivity and subsequent pregnancy/perinatal outcomes. Moreover, most subcategorized EMT to facilitate interpretation, which may have inadvertently introduced bias to the analyses. Study design, size, duration This retrospective, multicentre, cohort study analyzed all single blastocyst embryo transfers following oocyte donation from 2010-2019 subdivided into regular intervals of EMT (<7.0 mm, 7.0-8.9 mm, 9.0-10.9 mm, ≥11.0 mm). EMT was also evaluated as a continuous variable, comparing the best-fitting fractional polynomial against the linear function, to minimize bias due to residual confounding that may occur following the categorization of continuous variables. Confounder adjustment was performed using multivariable generalized estimating equations regression analysis. Participants/materials, setting, methods The oocyte donation model was chosen to minimize the influence of potential confounding factors such as poor embryo quality and the effect of ovarian stimulation on endometrial receptivity. The main objective of the study was to compare live birth rates (LBR). Our secondary outcomes included other surrogate pregnancy (hCG-positive pregnancy, clinical pregnancy, and miscarriage rates) and perinatal (gestational age at birth, preterm birth under 37 weeks, birthweight z-score, small and large for gestational age) outcomes. Main results and the role of chance In total, 33915 embryo transfers were analyzed. Confounder variables included were female donor and recipient age, recipient BMI, female factor infertility, male factor infertility, number of mature oocytes donated, oocyte status (fresh versus vitrified), sperm source (partner or donor), embryo status (fresh versus vitrified), embryo quality, endometrial preparation (natural or artificial cycle) and year of transfer. When compared to the reference EMT of 9.0-11.0 mm, EMT <7.0 mm was associated with lower hCG positive pregnancy rates (51.3% vs 57.6%; aOR 0.82 CI 0.75-0.89), lower clinical pregnancy (41.9% vs 49.1%; aOR 0.79 CI 0.73-0.86), higher miscarriage rates per hCG positive pregnancy (37.5% vs 31.4%; aOR 1.31 CI 1.16-1.47) and lower LBRs per transfer (32.1% vs 39.5%; aOR 0.76 CI 0.69-0.83). Regarding perinatal outcomes, we found significantly higher preterm delivery rates following an EMT <7.0 mm (14.1% vs 9.9%; aOR 1.54 CI 1.21-1.96) and higher large for gestational age rates associated with EMT ≥11.0 mm (16.4% vs 12.2%; aOR 1.40 CI 1.07-1.83). The fractional polynomial analysis revealed that the subcategorization of EMT caused clinically-relevant residual confounding. Specifically, LBRs assumed an approximate bell-shaped relationship with EMT, with LBR rates decreasing for both thinner EMTs (<7 mm subgroup) and thicker EMTs (≥11.0 mm subgroup). Limitations, reasons for caution The retrospective nature of the study and the inherent risk of bias related to unmeasured confounding may have impacted the results. Another potential limitation is the lack of perinatal outcome data due to loss of follow-up, which should be considered when interpreting these results. Wider implications of the findings Our results support the use of EMT as a predictor of live birth and as a marker of endometrial receptivity and competence. Moreover, it stresses the potential danger of subcategorizing all EMT <7.0 mm and >11.0 mm as equivalent, as the study found that these subgroups have varying LBR. Trial registration number not applicable

PO-01-051 EARLY PHYSICIAN ARRIVAL TO ELECTROPHYSIOLOGY LABORATORY INCREASES LAB EFFICIENCY BY DECREASING PREPARATION TIME

Many cardiac arrhythmia patients benefit from interventions performed in the electrophysiology (EP) lab. EP labs are a valuable resource that if not used efficiently may lead to delay in patient care, increased cost to the medical system, and challenges with recruiting and retaining staff. Prep time is defined as the time from when a patient (pt) enters a procedural room until the procedure start. Prep time is affected by many factors, including but not limited to: pt factors, staffing ratios, sedation plan, need for invasive hemodynamic monitoring, and complexity of procedure (proc). Physician arrival to the EP lab is an important component of prep time. To determine if earlier physician arrival to the EP lab shortens prep time. Pt and physician in-room times, proc start times, and proc characteristics were recorded over a 5 month period from 5/22 through 8/22. Quantitative data was divided into subgroups based on proc type – ablation (abl) or device. Means and standard deviation of physician arrival time and proc start time were calculated. A scatter plot of proc start time compared to physician arrival was created and a best-fit polynomial regression was performed (Fig 1). Point of maximum correlation (PMC) was calculated using Pearson’s method and linear regression was applied from that point onward. Cases that were understaffed and VT ablation were highlighted. Of 539 cases, 235 (44%) were device implants and 304 (56%) were abl. The difference between the earliest average physician arrival time compared to the latest average physician arrival time was 17min for device and 16 min for abl. Prep time was 15 minutes shorter for the earliest arriving physician for device, and 28 min shorter for abl. The PMC for abl and device implants were 25mins and 30mins respectively. Every minute of delay after the PMC was directly related to the MD not being present in the lab. For the interval prior to the PMC, there are many factors causing delays in the lab, leading to questionable direct correlation between MD arrival and prep time. The minimum prep time for both abl and implants appears to be 20 mins in this lab with the current staffing and culture. Earlier MD in room times increase lab efficiency by reducing procedure start times.Tabled 1Mean in Room Times to Access (min) +/-SDAblationDevice ImplantMean Pt Room to EP RoomMean Pt Room to AccessMean Pt Room to EP RoomMean Pt Rm to AccessEP115+/-1347+/-1111+/-1246+/-10EP211+/-942+/-1011+/-942+/-10EP318+/-850+/-1213+/-1647+/-16EP425+/-1449+/-1126+/-2149+/-16EP524+/-1660+/-2021+/-1652+/-14EP68+/-1032+/-84+/-837+/-9EP78+/-831+/-107+/-637+/-7 Open table in a new tab

Development of adiposity among Ju/'Hoansi Hunter-Gatherers.

To characterize the development of childhood adiposity among the Ju'/Hoansi, a well-known hunter-gather group, to compare our results to U.S. references and to recently published results from Savanna Pume' foragers of Venezuela, with the goal of expanding our understanding of adipose development among human hunter-gatherers. Triceps, subscapular, and abdominal skinfolds, along with height and weight from ~120 Ju'/Hoansi girls and ~103 boys, ages 0 to 24 years, collected in 1967-1969 were analyzed using best-fit polynomial models and penalized spines to characterize age-specific patterns of adiposity and their relationship to changes in height and weight. Overall, Ju/'Hoansi boys and girls exhibit small skinfolds with a decline in adiposity from 3 to 10 years, with no consistent differences among the three skinfolds. Increases in adiposity during adolescence precede peak height and weight velocities. Adiposity declines during young adulthood for girls and remains largely constant for boys. Compared to U.S. standards, the Ju/'Hoansi show a strikingly different pattern of adipose development, including the lack of an adiposity rebound at the onset of middle childhood, and clear increases in adiposity only at adolescence. These findings are consistent with published results from the Savanna Pumé hunter-gatherers of Venezuela, a group with a very different selective history, suggesting that the adiposity rebound does not characterize hunter-gathering populations more generally. Similar analyses in other subsistence populations are called for to confirm our results, and help distinguish the impact of specific environmental and dietary factors on adipose development.

Plücker coordinates of the best-fit Stiefel tropical linear space to a mixture of Gaussian distributions

In this research, we investigate a tropical principal component analysis (PCA) as a best-fit Stiefel tropical linear space to a given sample over the tropical projective torus for its dimensionality reduction and visualization. Especially, we characterize the best-fit Stiefel tropical linear space to a sample generated from a mixture of Gaussian distributions as the variances of the Gaussians go to zero. For a single Gaussian distribution, we show that the sum of residuals in terms of the tropical metric with the max-plus algebra over a given sample to a fitted Stiefel tropical linear space converges to zero by giving an upper bound for its convergence rate. Meanwhile, for a mixtures of Gaussian distribution, we show that the best-fit tropical linear space can be determined uniquely when we send variances to zero. We briefly consider the best-fit topical polynomial as an extension for the mixture of more than two Gaussians over the tropical projective space of dimension three. We show some geometric properties of these tropical linear spaces and polynomials.

Detrended fluctuation analysis based on best-fit polynomial

Detrended fluctuation analysis (DFA) can quantify long-range correlation (LRC) and fractal scaling behavior of signal. We compared the results of variant DFA methods by varying the order of the polynomial and found that the order of 6 was relatively better than the others when both the accuracy and computational cost were taken into account. An alternative DFA method is proposed to quantify the LRC exponent by using best-fit polynomial algorithm in each segment instead of the polynomial of the same order in all of segments. In this study, the best-fit polynomial algorithm with the maximum order of 6 is used to fit the local trend in each segment to detrend the trend of a time series, and then the revised DFA is used to quantify the LRC in the time series. A series of numerical studies demonstrate that the best-fit DFA performs better than regular DFA, especially for the time series with scaling exponent smaller than 0.5. This may be attributed to the improvement of the fitted trend at the end of each segment. The estimation results of variant DFA methods reach stable when the time series length is greater than 1,000.

Topographic evidence of long wavelength active folding in the New Madrid seismic zone, intraplate North America

The northeast-striking Axial and Bootheel faults (AF and BHF) in the central USA are components of the New Madrid seismic zone (NMSZ) fault complex, source of M > 7 earthquakes in 1811–1812. Previous work shows Holocene displacement of the AF and BHF to be primarily right-lateral strike-slip movement west and south of the NMSZ restraining bend. In this study, treads of two Late Pleistocene alluvial terraces of the Mississippi River, the 14–16 ka Kennett and the 12 ka Morehouse terraces, were used as structural datums to assess any long-wavelength vertical component of deformation across these two faults. Using 10 m-resolution LiDAR, we constructed a best-fit polynomial trend surface of these terrace treads. Our results reveal a subtle ≤4 m-deep, 40 km-wide, 190 km-long, topographic trough. In the south, it corresponds to the southern segment of the AF and parallels the BHF for 50 km. Farther north it corresponds to a syncline in subsurface Paleozoic strata 10 to 20 km northwest of and parallel to the BHF.The trough axis crosses obliquely down-valley from the younger Morehouse terrace to the older Kennett terrace and does not correspond to major drainages. Significantly, the Malden-Bernie fluvial scarp separating the two terraces continues into the trough but is down-warped, inconsistent with an erosional origin of the trough. Along the southern segment of the trough, the older Kennett tread is topographically lower than the Morehouse tread, but relict Kennett braided channels were not buried during deposition of younger Morehouse alluvium. This suggests the Kennett terrace tectonically subsided along the trough after Morehouse terrace deposition. We interpret this trough as a subtle syncline along the western margin of the NMSZ restraining bend that developed in response to down-on-the-northwest fault movement after deposition of Morehouse alluvium.

Is the Network of World Economic Forum Young Global Leaders Associated With COVID-19 Non-Pharmaceutical Intervention Severity?

Background TheWorld Economic Forum (WEF) has spawned a global network of elites called Young Global Leaders (YGLs) with significant influence on large corporations, politics, academia, and media. This article scrutinizes the idea that through this network, the WEF had a significant influence on the scale and scope of the non-pharmaceutical interventions (NPIs) implemented in response to the COVID-19 crisis. We tested for associations between the country-level distribution of YGLs and the intensity and duration of the implemented NPIs summarized by the Government Response Severity Index (GRSI). Materials and methods The number and category of YGLs per country was extracted from the WEF website. We also extracted the maximum and median GRSI values for three time periods: (i) the beginning of the first wave of the pandemic (March 1, 2020, to April 30, 2020), (ii) the height of the second wave in Europe (December 1, 2020, to January 31, 2021), and (iii) the approximate first year (March 1, 2020, to January 31, 2021). Being a precondition for causality, any association between the total or category-specific number of YGLs and the GRSI values in each time period was evaluated using Spearman's ρ correlation coefficients and polynomial regression, respectively. Results There was a highly significant positive correlation between the total number of YGLs in a country and the median (ρ = 0.36, p = 2.5×10-7) and maximum (ρ = 0.34, p = 1.6×10-6) GRSI during the second wave of the pandemic, but not during the first wave. The total number of YGLs was also a significant predictor of higher median GRSI during the second wave of the pandemic in the best-fitting (four-degree) polynomial regression model (p<0.01); additional significant and positive predictor in this model was a country's location within Europe or South America, respectively (p<0.01). Investigating an influence-weighted number of YGLs in business, politics, and civic society separately yielded no significant associations with NPI severity for any of the three time periods. Conclusions As there were significant correlations during the second, but not the first wave of the pandemic, we conclude that the WEF might not have been the origin of but rather an echo-chamber or amplifier for certain opinions and strategies that were formed and implemented during or before the first months of the COVID-19 crisis. Future qualitative studies may reveal putative causal mechanisms underlying our observed correlations.

Sagittal femoral condylar shape varies along a continuum from spherical to ovoid: a systematic review and meta-analysis.

Considerable anatomic variations of sagittal femoral condylar shape have been reported, with a continuum between spherical (or single-radius) and ovoid (or multi-radius) condyles. The purpose of this systematic review and meta-analysis was to critically appraise and synthesise the available literature on the sagittal femoral profile. The hypothesis was that studies would reveal considerable variability among individuals, but also in their methodology to quantify sagittal profiles. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. On 10 September 2021 two authors searched for Level I to IV studies that reported on the sagittal curvature of the medial and/or lateral femoral condyles using the MEDLINE®, EMBASE® and Cochrane Library. Results were summarised by tabulating means, standard deviations and/or ranges for the reported radii-of-curvature, or ellipsoidal semi-major and semi-minor lengths of the condyles. To quantify sagittal 'ovoidicity' and asymmetry, results were stratified according to coordinate reference frame (posterior condylar axis (PCA), clinical and surgical transepicondylar axis (cTEA and sTEA), unified sagittal plane (USP), or unclear) and summarised in forest plots as standardised mean differences (SMD). Thirty-eight articles wereeligible for full text extraction, quantifyingsagittal radii-of-curvature by best-fit circles (BFC), ellipsoids, polynomials, spherical or cylindrical fitting. Studies with clear definition of the measurement plane revealed that both condyles were generally ovoid, with considerably greater 'ovoidicity' at the medial condyle (SMD, 4.09) versus the lateral condyle (SMD, 3.33). In addition, distal condylar radii were greater medially when measured normal to the TEA (cTEA: SMD, 0.81; sTEA: SMD, 0.79), but greater laterally when measured in a USP (SMD, -0.83). Posterior condylar radii were greater laterally when measured in a USP (SMD, -0.60). Studies reported considerable variability of sagittal femoral condylar radii-of-curvature, which arenot incremental, but rathera continuum that ranges from spherical to ovoid. Although this variation could be accommodated by single-, dual- and multi-radii femoral components, a surgeon typically uses only one or two TKA designs. Hence, there is a risk of mismatch between the native and prosthetic sagittal profile that could result in mid-flexion ligament imbalance unless other parameters are changed. These findings support the drive towards patient-specific implants to potentially achieve accurate sagittal bone-implant fit through implant customisation. IV.

Significance of eigenstresses and curling stresses for total thermal stresses in a concrete slab, as a function of subgrade stiffness

ABSTRACT Thermally induced stresses of a concrete slab are quantified based on in situ temperature measurements. PT100A sensors recorded the temperature at four specific depths during 23 days in autumn. Best-fit quadratic polynomials are used to extrapolate the measured temperatures to the top and the bottom of the slab. The obtained surface temperature histories are used as boundary conditions for the solution of the transient heat conduction problem in thickness direction. Postprocessing the thermal eigenstrains provides access to the eigencurvatures of the plate and to the eigendistortions of the plate-generators. Stresses resulting from the constrained eigencurvatures of the plate are computed numerically, for values of the modulus of subgrade reaction amounting to 50, 100, 200, and 300 MPa/m. Self-equilibrated eigenstresses resulting from the prevented eigendistortions of the plate-generators are quantified analytically. Daily maxima of tensile stresses in corner regions at the top of the slab, and in the central region at its bottom, are found in the early morning and in the early afternoon, respectively. Disregarding the eigenstresses leads to an underestimation of tensile stresses in corner regions by at least 33 % and an overestimation in the central region by at least 26 % . The misestimations increase with decreasing modulus of subgrade reaction.

Exploring Changes in Quasar Spectral Energy Distributions across C iv Parameter Space

We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of mass and accretion rate. The clarity of these correlations is improved when (1) using C iv broad emission line equivalent width (EQW) and blueshift (relative to systemic) values calculated from high signal-to-noise ratio reconstructions of optical/UV spectra and (2) removing quasars expected to be absorbed based on their UV/X-ray spectral slopes. In addition to using the traditional C iv parameter space measures of C iv EQW and blueshift, we define a “C iv ∥ distance” along a best-fit polynomial curve that incorporates information from both C iv parameters. We find that the C iv ∥ distance is linearly correlated with both the optical-to-X-ray slope, α ox, and broad-line He ii EQW, which are known spectral energy distribution indicators, but does not require X-ray or high spectral resolution UV observations to compute. The C iv ∥ distance may be a better indicator of the mass-weighted accretion rate, parameterized by L/L Edd, than the C iv EQW or blueshift alone, as those relationships are known to break down at the extrema. Conversely, there is only a weak correlation with the X-ray energy index (Γ), an alternate L/L Edd indicator. We find no X-ray or optical trends in the direction perpendicular to the C iv distance that could be used to reveal differences in accretion disk, wind, or corona structure that could be widening the C iv EQW–blueshift distribution. A different parameter (such as metallicity) not traced by these data must come into play.

Arima Model Optimal Selection for Time Series Forecasting

Abstract A fast-and-flexible method of ARIMA model optimal selection is suggested for univariate time series forecasting. The method allows obtaining as-highly-accurate-as-possible forecasts automatically. It is based on effectively finding lags by the autocorrelation function of a detrended time series, where the best-fitting polynomial trend is subtracted from the time series. The forecasting quality criteria are the root-mean-square error (RMSE) and the maximum absolute error (MaxAE) allowing to register information about the average inaccuracy and worst outlier. Thus, the ARIMA model optimal selection is performed by simultaneously minimizing RMSE and Max-AE, whereupon the minimum defines the best model. Otherwise, if the minimum does not exist, a combination of minimal-RMSE and minimal-MaxAE ARIMA models is used.

Health-related quality of life and days alive without life support or out of hospital: Protocol.

Mortality is often the primary outcome in randomised clinical trials (RCTs) conducted in critically ill patients. Due to increased awareness on survivors after critical illness and outcomes other than mortality, health-related quality of life (HRQoL) and days alive without life support (DAWOLS) or days alive and out of hospital (DAAOOH) are increasingly being used. DAWOLS and DAAOOH convey more information than mortality, are easier to collect than HRQoL, and are usually assessed at earlier time points, which may be preferable in some situations. However, the associations between DAWOLS-DAAOOH and HRQoL are uncertain. We will assess associations between DAWOLS-DAAOOH at day 28 and 90 (independent variables/predictors) and HRQoL assessed using the EuroQol EQ-5D-5L questionnaire (EQ-VAS and EQ-5D-5L index values) at 6 or 12months (dependent variables) in two RCTs: the COVID STEROID 2 RCT conducted in adult patients with COVID-19 and severe hypoxaemia and the Handling Oxygenation Targets in the Intensive Care Unit (HOT-ICU) RCT conducted in adult intensive care patients with acute hypoxaemic respiratory failure. We will describe associations using best-fitting fractional polynomial transformations separately in each dataset, with the resulting models presented and assessed in both datasets graphically and using measures of fit and prediction adequacy (i.e., internal performance and external validation). We will use multiple imputation if missingness exceeds 5%. The outlined study will provide important knowledge on the associations between DAWOLS-DAAOOH and HRQoL in adult critically ill patients, which may help researchers and clinical trialists prioritise and select outcomes in future RCTs conducted in this population.

Studying the effect of the scanned objects’ location on material discrimination in a dual-energy cargo inspection system

Dual-energy X-ray radiography is an important inspection technology in imaging large cargos for finding illegal materials. A useful aspect of dual-energy X-ray radiography is the possibility of discriminating and identifying materials with different atomic numbers which can be obtained by imaging large cargos at two different X-ray energies (normally above 3 MeV). The performance of both single and dual-energy radiography depends on many factors such as beam energy and filtration, radiation dose, scanned object size, the content of the object, etc. One of the parameters that can affect the quality of the material discrimination is the location of the scanned objects (different heights from the ground). It is due to the fact that the generated X-ray beams from the Linac are angle dependent and therefore, energy spectrums vary at different angles. In this work, our main goal was to find equations for material discrimination curves as a function of height for graphite, aluminum, steel, and lead materials. After obtaining simulated and experimental curves for a range of heights, we searched for best-fitting polynomial equations and finally the best equation for each material was obtained. Our results showed that there is a good agreement between the simulated and experimental curves compared to those obtained from the fitted equations. According to obtained results, material discrimination curves can be obtained for a range of heights using the fitted equations without performing any further simulation and experimental processes. This can be very helpful in reducing calibration time and increasing calibration accuracy in inspection systems.

Spatial distribution of stable isotopes in surface water on the upper Indus River basin (UIRB): Implications for moisture source and paleoelevation reconstruction

Appropriate characterisation of isotope signatures (δ18O and δD) of groundwater, glaciers, and surface water in the Himalayan catchment are important for refining the sources of moisture and developing a modern isotope–elevation relationship for paleoelevation reconstructions. The Indus River located in Western Himalaya is previously unexplored in respect of the variation in water isotopic composition with elevation. In this study, water samples (n = 96) were collected from mainstream, tributaries, streams, glaciers, groundwater, lakes, hot springs, and pond water during the summer season. Results showed that δ18O signatures of the mainstream, tributaries and groundwater range from −15.1‰ to −12.3‰, −16.5‰ to −12‰, −13.8‰ to −12‰, with a mean value of −13.6‰, −14.7‰, −12.8‰, respectively. There was a northward rise in δ18O by 1.30‰ per degree of latitude in the tributary waters. The d-excess and δ18O values suggested that the key source of moisture in the studied river basin was mainly from westerlies and southwest monsoons. Thus, regional moisture recycling and subcloud evaporation contributed little in supplying moisture to the precipitation. The isotopic signature (δ18O) of the tributary stream and its surrounding regions conformed to a best-fit second-order polynomial relationship between δ18O and elevation over 3500 masl. Moreover, an δ18O elevation slope of −2‰/km is also established in this study area. This isotope–elevation relationship will be highly useful and can be applied to the Indus River and other Himalayan rivers for paleoelevation reconstruction.

Blood Pressure, Hypertension, and the Risk of Aortic Dissection Incidence and Mortality: Results From the J-SCH Study, the UK Biobank Study, and a Meta-Analysis of Cohort Studies.

Hypertension or elevated blood pressure (BP) is an important risk factor for aortic dissection (AD); however, few prospective studies on this topic have been published. We investigated the association between hypertension/elevated BP and AD in 2 cohorts and conducted a meta-analysis of published prospective studies, including these 2 studies. We analyzed data from the J-SHC study (Japan-Specific Health Checkups) and UK Biobank, which prospectively followed up 534 378 and 502 424 participants, respectively. Multivariable Cox regression was used to estimate hazard ratios and 95% CIs for the association of hypertension/elevated BP with AD incidence in the UK Biobank and AD mortality in the J-SHC Study. In the meta-analysis, summary relative risks were calculated with random-effects models. A potential nonlinear dose-response relationship between BP and AD was tested with fractional polynomial models, and the best-fitting second-order fractional polynomial regression model was determined. In the J-SHC study and UK Biobank, there were 84 and 182 ADs during the 4- and 9-year follow-up, and the adjusted hazard ratios of AD were 3.57 (95% CI, 2.17-6.11) and 2.68 (95% CI, 1.78-4.04) in hypertensive individuals, 1.33 (95% CI, 1.05-1.68) and 1.27 (95% CI, 1.11-1.48) per 20-mm Hg increase in systolic BP (SBP), and 1.67 (95% CI, 1.40-2.00) and 1.66 (95% CI, 1.46-1.89) per 10-mm Hg increase in diastolic BP (DBP), respectively. In the meta-analysis, the summary relative risks were 3.07 (95% CI, 2.15-4.38, I2=76.7%, n=7 studies, 2818 ADs, 4 563 501 participants) for hypertension and 1.39 (95% CI, 1.16-1.66, I2=47.7%, n=3) and 1.79 (95% CI: 1.51-2.12, I2 = 57.0%, n=3) per 20-mm Hg increase in SBP and per 10-mm Hg increase in DBP, respectively. The AD risk showed a strong, positive dose-response relationship with SBP and even more so with DBP. The risk of AD in the nonlinear dose-response analysis was significant at SBP >132 mm Hg and DBP >75 mm Hg. Hypertension and elevated SBP and DBP are associated with a high risk of AD. The risk of AD was positively dose dependent, even within the normal BP range. These findings provide further evidence for the optimization of BP to prevent AD.

Seven Decades of Coastal Change at Barter Island, Alaska: Exploring the Importance of Waves and Temperature on Erosion of Coastal Permafrost Bluffs

Observational data of coastal change over much of the Arctic are limited largely due to its immensity, remoteness, harsh environment, and restricted periods of sunlight and ice-free conditions. Barter Island, Alaska, is one of the few locations where an extensive, observational dataset exists, which enables a detailed assessment of the trends and patterns of coastal change over decadal to annual time scales. Coastal bluff and shoreline positions were delineated from maps, aerial photographs, and satellite imagery acquired between 1947 and 2020, and at a nearly annual rate since 2004. Rates and patterns of shoreline and bluff change varied widely over the observational period. Shorelines showed a consistent trend of southerly erosion and westerly extension of the western termini of Barter Island and Bernard Spit, which has accelerated since at least 2000. The 3.2 km long stretch of ocean-exposed coastal permafrost bluffs retreated on average 114 m and at a maximum of 163 m at an average long-term rate (70 year) of 1.6 ± 0.1 m/yr. The long-term retreat rate was punctuated by individual years with retreat rates up to four times higher (6.6 ± 1.9 m/yr; 2012–2013) and both long-term (multidecadal) and short-term (annual to semiannual) rates showed a steady increase in retreat rates through time, with consistently high rates since 2015. A best-fit polynomial trend indicated acceleration in retreat rates that was independent of the large spatial and temporal variations observed on an annual basis. Rates and patterns of bluff retreat were correlated to incident wave energy and air and water temperatures. Wave energy was found to be the dominant driver of bluff retreat, followed by sea surface temperatures and warming air temperatures that are considered proxies for evaluating thermo-erosion and denudation. Normalized anomalies of cumulative wave energy, duration of open water, and air and sea temperature showed at least three distinct phases since 1979: a negative phase prior to 1987, a mixed phase between 1987 and the early to late 2000s, followed by a positive phase extending to 2020. The duration of the open-water season has tripled since 1979, increasing from approximately 40 to 140 days. Acceleration in retreat rates at Barter Island may be related to increases in both thermodenudation, associated with increasing air temperature, and the number of niche-forming and block-collapsing episodes associated with higher air and water temperature, more frequent storms, and longer ice-free conditions in the Beaufort Sea.

Reference values for left and right ventricular systolic-to-diastolic duration ratio (SDR) found using both spectral and tissue Doppler of fetal heart between 20 and 36+6weeks of gestation.

To establish reference values for the systolic-to-diastolic duration ratio (SDR) of the left ventricle (LV) using spectral Doppler, as well as for the SDR' of the interventricular septum (SEP), LV, and right ventricles (RV) using tissue Doppler of the fetal heart. This prospective and cross-sectional study evaluated 374 low-risk singleton pregnancies from 20 to 36+6weeks of gestation. The ventricular filling time (FT) was obtained from LV inflow using spectral Doppler. Tissue Doppler was used to assess the FT of each ventricle by placing the cursor at the atrioventricular junction marked by the mitral and tricuspid valves, respectively. SDR was calculated as the sum of the isovolumic contraction time (ICT) and the ejection time (ET) divided by the sum of the isovolumic relaxation time (IRT) and the ventricular FT. We used regression analysis to obtain the best-fit model polynomial equation for the parameters. The concordance correlation coefficient (CCC) was used to assess intra- and inter-observer reproducibility. SDR and SDR' LV showed a progressive decrease with gestational age (GA); the SDR' RV and SDR' SEP did not show a significant decrease with advancing GA. The SDR LV (r=0.29, p<0.0001), SDR' RV (r=0.21, p<0.0001), SDR' LV (r=0.20, p=0.0001), and SDR' SEP (r=0.25, p<0.0001) showed a significant weak positive correlation with fetal heart rate. The inter-observer SDR' SEP measurements demonstrated poor reproducibility (CCC: 0.50), whereas intra-observer SRD LV measurements demonstrated moderate reproducibility (CCC: 0.78). Reference values for SDR SEP, LV, and RV using spectral and tissue Doppler of fetal heart were established between 20 and 36+6weeks of gestation.