Usual Values Research Articles

Evaluation of Vitamin B12 deficiency Anemia in Geriatric Patients

Objective: In our study, we aimed to evaluate vitamin B12 deficiency anemia, macrocytosis rate and vitamin B12 values in patients over 65 years of age and compare them with those under 65 years of age.groups. Methods: Retrospectively, A total of 8062 patients, 1213 over the age of 65 and 6849 under the age of 65, admitted between March 2019 and March 2024 were included in the study. The patients' hemoglobin, hematocrit, MCV, White blood cell (WBC), Red cell distribution width (RDW), Platelet (PLT) values and vitamin B12 levels were examined. Patients were divided into two groups as age of 65 and over and age below 65, and each group were divided into two groups in terms of anemia. Groups and subgropus were compared with each other Results: While the ratio of vitamin b12 deficiency anemia in patients over 65 years of age was 20.2%, the ratio of anemia in patients under 65 years of age was 8.3%. It was observed that there was no significant difference in vitamin B12 levels in terms of gender in both age groups. With the roc analyses the cut-off value for vitamin B12 causing anemia in patients over 65 years of age was 327 pg/mL (AUC: 0.602, p≤0.001) with a sensitivity of 94.3% and specificity of 34.2%. Conclusion: The fact that vitamin B12 levels that cause anemia in elderly patients are higher than in young-adult patients made us think that the usual limit values may need to be reconsiderated in geriatric population

Comparisons of computer simulations and experimental data for capacitive hyperthermia using different split-phantoms

Introduction Several positive clinical trials have demonstrated that capacitive hyperthermia (CHT) improves the effectiveness of radiation therapy for the treatment of various cancer entities. However, the ability of CHT to induce significant heating throughout the body is under debate. Objectives To perform a pilot study involving comparisons of computer simulations and experimental data using different split-phantoms to validate hyperthermia treatment modeling for pre-planning for a clinical CHT system and to investigate the feasibility of split-phantom measurements in capacitive hyperthermia. Materials and methods The CHT system EHY-2030 (Oncotherm, Budapest, Hungary) was used. The system provides two electrode sizes, but only the smaller electrode, indicated as D200 electrode, was investigated in this pilot study. Horizontally and vertically splittable, different multi-slice phantoms with dielectric material properties simulating muscle and electrically low conductive fat were produced and heated. During the heating procedure, temperature-time curves were measured, and thermal images were captured. Specific absorption rate values were derived from the temperature rise (TR) values. Concomitantly, computer field simulations utilizing a detailed CAD-based model of the CHT system were performed using the simulation platform Sim4Life and compared with measurements. Results For the investigated electrode D200 the system power of 75 W was applied, which is half of the maximum power of 150 W and lies in the range of usual values for this electrode applied in patient treatments in our clinic. For 75 W, a heating of 3.6 °C in 6 min in a depth of 1 cm in an agar-based, muscle tissue-equivalent phantom was achieved. The addition of a 1 cm thick, synthetic, low dielectric fat layer reduced the TR up until a depth of 8.5 cm by on average around 38% (from 8.5 cm onwards the absolute local TR is similar, deviations are ≤0.1 °C). In terms of point-to-point absolute SAR comparison (without any normalization), up to a depth of 11 cm in the phantoms central vertical plot, the simulation differs from the measured TR points by on average 25% (ranging from 7% to 36%) for the homogeneous phantom and by on average 43% (ranging from 26% to 60%) for the inhomogeneous phantom. Conclusion Computer simulations and experimental data were compared for the CHT system EHY-2030 using the D200 electrode, applying a thermal imaging technique for different vertically splittable phantoms. This pilot study data can be used as a guidance regarding the expected heating for this commonly used electrode size but also to further elucidate the significance of non-thermal anticancer effects. Further studies are needed for different sizes and geometries of electrodes and phantoms.

Investigation of models for predicting the effectiveness of acid treatments in carbonate deposits

This article presents the results of an analysis of the available literature data on the acid treatment of carbonates based on the solution approach. The analysis of various acid treatment liquids, the choice of additives and modeling procedures was also carried out in order to optimally design the process of acid treatment of carbonates. Although theoretical models are designed to predict the effectiveness of acid treatments, their practical applicability for scaling at the field level remains uncertain. Scaling laboratory data to the optimal rate does not always lead to results corresponding to the usual values of processing at the field. In modern models, it is proposed to use the geometry of the pipe to calculate the dominant penetration of wormholes and take into account the competition between them, introducing the density of wormholes in a porous medium. However, assigning values that are sensitive to the rock structure and injection conditions is a major difficulty. Instead of predicting the length of dominant wormholes, it is preferable to focus on estimating the permeability resulting from acid injection. However, the permeability assessment is not possible without first calculating the dissolution coefficient. The simulation results demonstrate that the existence of various zones of recesses or cracks in the formation has a significant impact on the acidification process, especially on the direction of wormhole propagation. This direction can be partially controlled by adding deflecting or retarding agents.

Extension of Delaunay normalisation for arbitrary powers of the radial distance

In the framework of perturbed Keplerian systems we deal with the Delaunay normalisation of a wide class of perturbations such that the radial distance is raised to an arbitrary real number γ. The averaged function is expressed in terms of the Gauss hypergeometric function 2F1 whereas the associated generating function is the so called Appell hypergeometric function F1. The Gauss hypergeometric function related to the average depends on the eccentricity, e, whereas the Appell function depends additionally on the eccentric anomaly, E, and both special functions are properly defined and evaluated for all e∈[0,1) and E∈[−π,π]. We analyse when the functions we determine can be extended to e=1. When the exponent of the radial distance is an integer, the usual values of the averaged and generating functions are recovered.

Surface roughness effects on transonic aircraft performance: Experimental/numerical comparisons

This work highlights the necessity of taking into account surface roughness when conducting experimental tests, and when using numerical simulations to precisely calculate the turbulent lift and drag of wind-tunnel models or real aircraft in transonic conditions. The present article is a continuation of “Turbulent drag induced by low surface roughness at transonic speeds: Experimental/numerical comparisons,” Physics of Fluids, Vol. 32, 045108 (2020) by Hue and Molton. The outcomes of this former study, which was focused on flat plate samples, are here applied to a three-dimensional aircraft configuration: the Common Research Model used as a reference in the recent international Drag Prediction Workshops. Experimental campaigns have been performed in the largest ONERA wind tunnels S1MA and S2MA involving models with average surface roughness heights Ra close to 0.5 micrometers, wingspans up to 3.5 meters, Mach and Reynolds numbers up to 0.95 and 5 million respectively. Reynolds-averaged Navier–Stokes computations based on the wind-tunnel tests have then been carried out, using the equivalent sand-grain roughness height approach as well as a Musker-type correlation to determine relevant ks values. The results of both the experimental and numerical campaigns have demonstrated that the aerodynamic coefficients of the aircraft can be significantly affected by the surface roughness, even with roughness Reynolds numbers ks+ potentially below the usual threshold values sometimes considered in engineering applications (i.e. in the order of 3.5 to 5). In particular, the surface roughness effects on lift and drag have been studied using far-field analyses to evaluate the responses of friction, viscous pressure, wave and lift-induced drag components. Finally, the numerical studies have been extended to the full-scale geometry in flight conditions in order to assess the roughness effects and potential gains in realistic aircraft operating conditions.

Energy Loss Index and Dimensionless Index Outperform Direct Valve Planimetry in Low-Gradient Aortic Stenosis.

Background/Objectives: Among patients with suspected severe aortic stenosis (AS), discordance between effective orifice area (EOA) and transvalvular gradients is frequent and requires a multiparametric workup including flow assessment and calcium-scoring to confirm true severe AS. The aim of this study was to assess direct planimetry, energy loss index (Eli) and dimensionless index (DI) as stand-alone parameters to identify non-severe AS in discordant cases. Methods: In this prospective cohort study, we included consecutive AS patients > 70 years with EOA < 1.0 cm2 referred for valve replacement between 2014 and 2017. AS severity was retrospectively reassessed using the multiparametric work-up recommended in the 2021 ESC/EACTS guidelines. DI and ELi were calculated, and valve area was measured by direct planimetry on transesophageal echocardiography. Results: A total of 101 patients (mean age 82 y; 57% male) were included. Discordance between EOA and gradients was observed in 46% and non-severe AS found in 24% despite an EOA < 1 cm2. Valve planimetry performed poorly, with an area under the ROC curve (AUC) of 0.64. At a cut-off value of >0.82 cm2, sensitivity and specificity to identify non-severe AS were 67 and 66%, respectively. DI and ELi showed a higher diagnostic accuracy, with an AUC of 0.77 and 0.76, respectively. Cut-off values of >0.24 and >0.6 cm2/m2 identified non-severe AS, with a high specificity of 79% and 91%, respectively. Conclusions: Almost one in four patients with EOA < 1 cm2 had non-severe AS according to guideline-recommended multiparametric assessment. Direct valve planimetry revealed poor diagnostic accuracy and should be interpreted with caution. Usual prognostic cut-off values for DI > 0.24 and ELI > 0.6 cm2/m2 identified non-severe AS with high specificity and should therefore be included in the assessment of low-gradient AS.

Large Anomalous Hall Effect at Room Temperature in a Fermi‐Level‐Tuned Kagome Antiferromagnet

AbstractThe recent discoveries of surprisingly large anomalous Hall effect (AHE) in antiferromagnets have attracted much attention due to their promising use in spintronics devices. However, such AHE‐hosting antiferromagnetic materials are rare in nature. Herein, it is demonstrated that Mn2.4Ga, a Fermi‐level‐tuned kagome antiferromagnet, has a large anomalous Hall conductivity of ≈150 Ω−1 cm−1 at room temperature that surpasses the usual high values (i.e., 20–50 Ω−1 cm−1) observed so far in two outstanding kagome antiferromagnets, Mn3Sn and Mn3Ge. Although the triangular spin structure of Mn2.4Ga shows a weak net magnetic moment of ≈0.05 µB per formula unit, it guarantees a nonzero Berry curvature in the kagome plane. Moreover, the anomalous Hall conductivity exhibits a sign reversal with the rotation of a small magnetic field that can be ascribed to the field‐controlled chirality of the spin triangular structure. This theoretical calculations further suggest that the large AHE in Mn2.4Ga originates from a significantly enhanced Berry curvature associated with the tuning of the Fermi level close to the Weyl points. These properties, together with the ability to manipulate moment orientations using a moderate external magnetic field, make Mn2.4Ga extremely exciting for future antiferromagnetic spintronics.

Phytoplankton change along the length of the Ural River under conditions of eutrophication

For the first time, the change of phytoplankton along the length of the Ural River from Verkhneuralsk to Orenburg (on a site of more than 1000 km) was studied. A powerful eutrophying effect of Magnitogorsk on the river for more than 150 km has been revealed. It manifests itself in the fact that the phytoplankton biomass in this area increases greatly, averaging about 15 mg/ l (with the dominance of cyanobacteria Microcystis aeruginosa), and the species diversity index (Shannon index), on the contrary, reaches extremely low values of 0.25. This indicates a significant oppression of the plankton community and deterioration of water quality. In the Ural River above this site (from Verkhneuralsk to Magnitogorsk reservoir), as well as below it (from Orsk to Orenburg), phytoplankton indicators correspond to the usual values: biomass is 1.6–1.7 mg/l, Shannon index is 3.3–3.5 (on average for each site). This suggests that the conditions for the existence of plankton in the upper and lower areas are favorable. At the same time, the sites differ in the composition of algae: the first is dominated by diatoms, the second is predominantly green. Perhaps this is due to geographical factors: in the north, the Urals flows in the forest-steppe zone, and in the south it passes into the steppe.

Influence of organic and cage housing system on egg quality in laying hens

Abstract Most of the eggs for consumption are produced in a conventional housing system although the demand for organic eggs is increasing because consumers assume better nutritional characteristics. This study was conducted to compare the quality of organic eggs and enriched cage eggs. A total of 409 organic eggs and 385 eggs from hens housed in enriched cages were directly collected from 15 different farms, located in Spain and were analyzed within 4 days after laying. The differences in quality by removing the time bias that can be caused by marketing time were thus determined. All the hens were of three different lines, 47–50 weeks old and consumed commercial feed with the same nutritional composition. The quality traits evaluated were egg weight (EW g), egg shape index (SI), shell thickness (ST), shell percentage (SP), Haugh units (HU), dense albumen percentage (DAP), total albumen percentage (TAP), yolk color (YC), yolk percentage (YP), Roche scale (RS), moisture (M), ash content (AC), total protein (TP), total yolk carotenoids (TYC), total fat (TF), saturated fatty acids (SFA), monounsaturated fatty acids (MFA), and polyunsaturated fatty acids (PFA). Estimates of differences were obtained by generalized least squares using housing system, genetic line and their interaction as factors. Significant differences were observed for EW (65.3 vs 62.9), SI (77.60 vs 76.10), HU (83.60 vs 81.80), TAP (66.5 vs 64.17), YC (3.11 vs 1.89), RS (11.79 vs 9.48), TP (9.99 vs 8.55), TYC (4.188 vs 2.650), SFA (32.20 vs 30.00) and MFA (53.40 vs 44.20) in favor of the enriched cage system. In the organic system, the quality parameters that had higher and significant values were ST (0.34 vs 0.32), SP (10.52 vs 9.41), YP (25.20 vs 24.30), AC (1.12 vs 0.93) and PFA (26.00 vs 14.00). Significant interactions between the housing system and the hen line followed the same pattern observed for fixed effects. Organic eggs were lighter, less rounded with better shell quality and therefore showed lower Haugh unit values and a lower albumen percentage. Total protein, total fat, and lipid profile were within the usual average values for commercial eggs, although the proportion of polyunsaturated fatty acids, which are beneficial for consumers, was higher in organic eggs.

Toxic metals in cyanobacterial mat of Big Lachman Lake, James Ross Island, Antarctica.

The northern part of James Ross Island is the largest deglaciated area in the Antarctic Peninsula region with a unique ecosystem created during the Late Glacial. This research aims to evaluate the degree of contamination of the locality with toxic metals (As, Hg, Cd, and Pb) through bioindicators in the aquatic environment-colonies of cyanobacteria and algae. For this purpose, bottom lake sediments of Big Lachman Lake were studied for contents of Fe, As, Hg, Cd, Pb, Cr, Co, Ni, Cu, and Zn, as well as samples of cyanobacterial mat, in which Fe, As, Hg, Cd, and Pb were determined. Metal contents were determined by means of inductively coupled plasma optical emission spectrometry and atomic absorption spectrometry. The contents of metals in sediments did not differ from the usual values in the area of the Antarctic Peninsula. The bioaccumulation of metals in cyanobacterial mat was evaluated by calculating enrichment factors (the calculation to Fe as a reference element). According to this method, moderate pollution of Big Lachman Lake was confirmed for Hg and Cd.

Respiratory distress in Holstein cows fed corn silage: case report

An outbreak of respiratory distress was observed in Holstein cows immediately after consuming a new batch of corn-silage, presumably due to the presence of pneumotoxic gases. Signs were observed in 10% of the cows, and characterized as tachypnea, orthopneic position, cough and notable anxiety a few minutes after offering the silage. No deaths were recorded. Mild leucocytosis was observed in the hemogram. Nutritional analysis and nitrate determination of the corn-silage revealed usual values. Nitrous oxide and methane concentration were evaluated by gas chromatography and nitrogen oxides concentration directly with a portable device, resulting in acceptable values. Although high concentrations of toxic gases could not be evidenced in the air sampled on farm, the clinical signs observed coincide with those reported in cases of exposure to gases formed during corn silage processes. A greater emphasis is required in the evaluation of the corn to be ensiled, given the possible existence of factors that can generate the accumulation of potentially toxic gases for cattle that affect negatively their health and productivity.

Genetic Diversity in Peripheral Pedunculate Oak (Quercus robur L.) Provenances—Potential Climate Change Mitigators in the Center of Distribution despite Challenges in Natural Populations

Croatian pedunculate oak (Quercus robur L.) populations represent southern range peripheral populations, often viewed as sources of valuable diversity and drought-resistant ecotypes. At the same time, they endure stronger selection pressures as a result of climate change. The leaves of 20 individuals per population (17) were sampled in a field trial and analyzed using 10 nuclear and 9 chloroplast SSRs to determine the level of intrapopulation genetic variability and genetic differentiation. Analysis with nSSRs revealed deviation from HWE in seven populations. AMOVA showed a high intra-population diversity (98.53%) and a small but statistically significant inter-population differentiation. Isolation by distance explained 19.6% of differentiation. Average FST between populations was low (0.013) compared with usual values for peripheral populations. Populations were rich in cpSSR haplotypes, confirming the hotspot of diversity caused by the encounter of recolonization routes. Unbiased haplotype diversity (HE) from 9 chloroplast SSRs and 325 individuals was (HE = 0.440). Sixty-six different haplotypes were grouped in three maternal lineages by both a median-joining network and a neighbor-joining algorithm. AMOVA for cpSSRs showed statistically significant diversity among populations (70.23%), suggesting genetic differentiation, but also a probable anthropogenic effect. AMOVA of nSSRs within and between lineages showed that original recolonization patterns of nuclear diversity were subsequently erased by gene flow.

The association between anterior chamber biometry and posterior capsular defects.

To analyze the association between anterior chamber biometric factors and posterior capsular defects (PCDs) that occur during extracapsular cataract extraction. University Eye Hospital, Goethe University Frankfurt, Germany. Population-based study. Extracapsular cataract extractions for inpatient cases within four years were retrospectively analyzed. The data on the occurrence of PCDs, age, sex, surgeon, and biometry were obtained. For cases with PCDs, the secondary ocular diseases, number of procedures, lens implant, visual acuity, and course were also recorded. Swept-source OCT measurements allowed the measurement of lens thickness (LT) in addition to the usual biometry values. A total of 1967 cataract surgeries (patients age: 70.56 ± 8.42, 1005 women; 962 men) were included, and PCDs were documented for 59 (2.54 %; 31 women, 28 men) cases (patient age: 70.95 ± 8.52 years). There were no differences (p = 0.76) related to the surgeons (n=9) with minimal effect sizes. The mean LT, axial length, corneal curvature, and anterior chamber length were 4950.36 ± 466.63 μm, 23.73 ± 1.77 mm, 43.89 ± 1.36 diopters, and 3.02 ± 0.71 mm, respectively. The Wilcoxon-Mann-Whitney test showed significant associations between LT (p = 0.01) and PCDs with moderate relevance for the Rosenthal effect size (LT R = 0.34; ACD R = 0.29). In addition to ACD, a tendency for the occurrence of PCD could be proven, especially for LT.Therefore, special attention should be paid to LT preoperatively for comprehensive risk stratification.

Hand function and quality of life in patients with diabetes mellitus before and during the COVID-19 pandemic.

This study aimed to investigate the effects of the coronavirus disease 2019 (COVID-19) pandemic on patients with diabetes mellitus using patient-rated outcome measures focusing on hand function and quality of life, as well as patients' mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. It was a part of a longitudinal research involving patients with diabetes mellitus living in Sapporo, Japan. Among the 594 patients surveyed before the COVID-19 pandemic from March to June 2019, 417 patients who could be re-surveyed from March to June 2021 were included. We compared the patient-rated outcome measures, namely the Hand10 for hand function and EuroQol five-dimension questionnaire for assessing quality of life in the same population of patients with diabetes mellitus, before and during the COVID-19 pandemic. The results indicated no deterioration in the Hand10 (3.9 vs 3.6) and quality of life scores (0.89 vs 0.9), including mobility (1.25 vs 1.17), self-care (1.1 vs 1.08), pain/discomfort (1.43 vs 1.35), and anxiety/depression (1.21 vs 1.2), during the COVID-19 pandemic when compared with the pre-pandemic values. Usual activity values on the EuroQol five-dimension subscale significantly improved during the pandemic compared to those before the pandemic (1.21 vs 1.12, p<0.01). This study highlighted the effects of the COVID-19 pandemic on patients with diabetes mellitus by comparing patient-rated outcome measures in two different social situations. Patients with diabetes mellitus living in Sapporo, Japan maintained hand function and quality of life by continuing their usual activities during the COVID-19 pandemic.

Regression in extremes using the four-parameter Kappa distribution

The four-parameter Kappa distribution (4KD) is known to be flexible and has been used for extreme value analysis, especially in hydrological sciences. This distribution has the great advantage of encompassing the two main distributions of extreme values used in the literature: the Generalized Pareto Distribution (GPD) and the Generalized Extreme Value (GEV) distribution. However, the analyses made in previous works for 4KD in the context of extreme values are based only on models with static parameters, not allowing the capture of covariate effects such as seasonality and location variables in a specific dataset. This study proposes that the inference about the 4KD can be made under the Bayesian paradigm by inserting a regression structure on the parameters to assess possible effects of covariates under the model. This proposal allows us to interpret the parameters and predict extreme events when there are covariates. The estimation of the parameters is performed using Markov Chain Monte Carlo (MCMC) procedures. The model was applied with both approaches in extremes: maximum and exceedance data. In this analysis, the proposed model was compared with models that use a regression structure in the usual extreme values distribution (GEV and GPD), and it presented better results in fit measures.

Interchangeability between factor analysis, logistic IRT, and normal ogive IRT.

In existing studies, it has been argued that factor analysis (FA) is equivalent to item response theory (IRT) and that IRT models that use different functions (i.e., logistic and normal ogive) are also interchangeable. However, these arguments have weak links. The proof of equivalence between FA and normal ogive IRT assumes a normal distribution. The interchangeability between the logistic and normal ogive IRT models depends on a scaling constant, but few scholars have examined whether the usual values of 1.7 or 1.702 maximize interchangeability. This study addresses these issues through Monte Carlo simulations. First, the FA model produces almost identical results to those of the normal ogive model even under severe nonnormality. Second, no single scaling constant maximizes the interchangeability between logistic and normal ogive models. Instead, users should choose different scaling constants depending on their purpose in using a model and the number of response categories (i.e., dichotomous or polytomous). Third, the interchangeability between logistic and normal ogive models is determined by several conditions. The interchangeability is high if the data are dichotomous or if the latent variables follow a symmetric distribution, and vice versa. In summary, the interchangeability between FA and normal ogive models is greater than expected, but that between logistic and normal ogive models is not.

Biomarkers of Adverse Cardiovascular Events in Kidney Disease

Based on domestic and international literature the review refers to the analysis of the research data on risk factors and biomarkers for the development of adverse cardiovascular events in patients with chronic kidney disease and acute kidney injury. Biomarker studies are important, especially in the early stages of chronic kidney disease, that is, in patients with creatinine clearance above 60 ml/min/1.73 m2, when preventive and therapeutic measures work more effectively. Among the potential predictors of adverse cardiovascular events, the biomarkers related to the following pathological processes (conditions) should be noted: oxidative stress (malondialdehyde, ischemic-modified albumin; superoxide dismutase), inflammation (interleukin-6, interleukin-18), acute kidney injury (kidney injury molecule 1; neutrophil gelatinase-associated lipocalin), cardiospecific biomarkers (highly sensitive troponin) and circulating microribonucleic acids (specific miRNA-133a, miRNA-21), as well as the prospects for further study of some biomarkers in cardionephrology are discussed. A separate emphasis is placed on the need to establish threshold values for various molecules in chronic kidney disease, depending on the degree of decline in kidney function, which will allow these indicators to be effectively used in clinical practice as diagnostic and prognostic biomarkers for cardiovascular diseases, since their usual reference values are used in the general population, will be higher in kidney disease. Currently, only for troponin and natriuretic peptides, certain reference values are established, which are less clear-cut in the population with chronic kidney disease than in the general population, and for all other biomarkers, cut-off values are not yet known.

Numerical convergence does not mean mathematical convergence: Examples of simple saturated steady-state groundwater models with pumping wells

Groundwater numerical studies do not include H-convergence tests, contrarily to computational fluid dynamics (CFD) studies. In regional groundwater studies with pumping wells, the grids may exceed 106 nodes. The authors examine whether H-convergence tests can help to calculate the numerical errors made by using large grids with element sizes in the 10–500 m range. First, the differences between numerical and mathematical convergences are explained. Then, a method is proposed that most users may easily implement for their groundwater studies to assess the numerical error linked to the element size, ES, and the aspect ratio, AR. A single problem, forming a simple part of a regional groundwater study, was examined and solved by using many uniform grids. The results show that most regional groundwater studies make errors in the 50–500% range, considering their usual values for ES and AR. The numerical convergence domain, NCD, is shown to be larger than the mathematical convergence domain, MCD. This means that the codes can provide a numerical solution for a large range of ES values, even for many values outside the MCD, which is a risky situation for designers who are unaware of the difference between NCD and MCD and ignore the H-convergence tests.

Service-life prediction of recycled coarse aggregate concrete under natural carbonation: A time-dependent reliability analysis

Carbonation is a phenomenon that involves several uncertainties associated with concrete properties and environmental factors. However, most existing studies have adopted a deterministic approach to deal with this phenomenon, which can lead to misinterpretations. This study aimed to carry out a probabilistic analysis of natural carbonation with data collected for over 30 months of recycled coarse aggregate (RCA) concretes and natural coarse aggregate concretes (NCA), used as reference. The probabilistic analysis showed that the cover depth collected in field presented a normal distribution behavior, in this way, random variables were generated to sample cover depth values to be used in time-dependent Monte Carlo simulations. A computational algorithm was developed in MATLAB to evaluate the probability of the carbonation depth (xc) overcoming cover depths (cd) of 15-, 20-, 25-, 30-, 35-, and 40-mm, usual values in structural design. The simulations showed that the RCA anticipated the probability of failure (xc ≥ cd) by up to 100 months compared to natural coarse aggregate (NCA) concrete. The results indicated that the total replacement of NCA by RCA requires increases of up to 1.4 in cover depth to perform equivalently to the reference concrete (with NCA). Moreover, regardless of the type of aggregate and w/c ratio, with the cover depth established in the Brazilian standard for urban environments, the evaluated concrete did not reach the minimum service life of 50 years established for structural elements of reinforced concrete. The methodology applied in this paper can be used to predict the service-life considering failure due to carbonation using the statistics response of experimental data.

Coronal Elemental Abundances During A-Class Solar Flares Observed by Chandrayaan-2 XSM

The abundances of low First Ionisation Potential (FIP) elements are three to four times higher (FIP bias) in the closed loop active corona than in the photosphere, known as the FIP effect. Observations suggest that the abundances vary in different coronal structures. Here, we use the soft X-ray spectroscopic measurements from the Solar X-ray Monitor (XSM) on board the Chandrayaan-2 orbiter to study the FIP effect in multiple A-class flares observed during the minimum of solar cycle 24. Using time-integrated spectral analysis, we derive the average temperature, emission measure, and the abundances of four elements - Mg, Al, Si, and S. We find that the temperature and emission measure scales with the flares sub-class while the measured abundances show an intermediate FIP bias for the lower A-flares (e.g., A1), while for the higher A-flares, the FIP bias is near unity. To investigate it further, we perform a time-resolved spectral analysis for a sample of the A-class flares and examine the evolution of temperature, emission measure, and abundances. We find that the abundances drop from the coronal values towards their photospheric values in the impulsive phase of the flares, and after the impulsive phase, they quickly return to the usual coronal values. The transition of the abundances from the coronal to photospheric values in the impulsive phase of the flares indicates the injection of fresh unfractionated material from the lower solar atmosphere to the corona due to chromospheric evaporation. However, explaining the quick recovery of the abundances from the photospheric to coronal values in the decay phase of the flare is challenging.