Significant Underestimation Research Articles

Solar nanoflares in different spectral ranges

Aims. The rates and other characteristics of solar nanoflares were measured for the same area of the Sun in different extreme-ultravioilet (EUV) channels to find how the main properties of nanoflares depend on the spectral range. Methods. We used images of the quiet Sun obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) in seven spectral channels, 94 Å, 131 Å, 171 Å, 193 Å, 211 Å, 304 Å, and 335 Å. We analyzed 300 images for each AIA/SDO channel covering one hour from 12:00 UT to 13:00 UT on 20 May 2019 with a 12 s cadence. We searched for nanoflares in two 360″×720″ fields of view above (N) and below (S) the Sun’s equator to measure nanoflare latitudinal distributions and their N–S asymmetry. To detect nanoflares, we used a threshold-based algorithm with 5σ threshold. Results. The integral nanoflare rate measured in seven spectral ranges is 3.53 × 10−21 cm−1 s−1; the corresponding frequency is 215 events s−1 for the entire surface of the Sun. A search for nanoflares in any single AIA-channel leads to significant underestimation of their frequency and rate: 171 Å −34% of the total value; 193 Å −33%; 211 Å −24%; other channels – less than 16%. Most EUV nanoflares are single-pixel (∼78%) and mono-channel (∼86%) events. In channel 304 Å, multipixel events dominate over single-pixel events (68% vs. 32%). The average duration of nanoflares is in the range of (89 − 141)±(40 − 61) s depending on the spectral region with the mean value being 129 ± 59 s. The latitudinal distribution of nanoflares is approximately uniform in the range from 0° to 45° for all channels. We find a slight difference between the N and S hemispheres (up to 20% depending on channel), but we do not find it to be statistically significant. Conclusions. We demonstrate that solar nanoflares can be found in all AIA EUV channels. The detection probability strongly depends on the spectral range and the channels can be approximately ranked as follows (from high to low probability): 171 Å, 193 Å, 211 Å, 131 Å, 304 Å, 335 Å, and 94 Å. The first three channels, 171, 193, and 211 Å, allow the detection of ∼78% of all the nanoflares. The remaining four add only 22%. Other characteristics of nanoflares, including duration and spatial distribution, weakly depend on spectral range.

Development of a rock-bit interaction analytical model by considering the in-situ stresses for a bottom-hole element

PDC drill bits are an important part of drilling engineering, but improper selection or design can lead to decreased performance and increased costs. Then, accurate modeling of rock-bit interaction for Oil/gas well drilling is critical. Although several mathematical models are presented for this purpose, they have not been able to present a comprehensive model for the rock-bit interaction. In-situ stresses in real drilling conditions affect the force required for rock failure. However, the models proposed so far either have not considered the effects of in-situ stresses or have assumed that the rock failure angle in the downhole conditions is equal to the one calculated in the atmospheric conditions. In this work, after reviewing the background of studies conducted on the rock and bit interaction, with an analytical method, stresses applied to the bottom hole element are examined, including stresses resulting from bit and in-situ stresses. Based on the principle of superposition, the total stress imposed on the bottom hole element is calculated to determine the angle and force of rock cutting. Finally, a novel mathematical model of rock-bit interaction in vertical and deviated oil/gas wells drilling by Considering In-Situ Stresses is presented. Also, the study compares the current model to the Nishimatsu and Xin Ling models using data from a southwest field in Iran. The results show that the simplifying assumption made by previous models leads to a significant underestimation of the failure angle and the amount of force required to the rock failure, with reductions of up to 21% and 48%, respectively, in the case of a vertical well. In an inclined well, the current model predicts cutting force at about 0.14 of that predicted by the previous model.

Impact of Saharan dust outbreaks on short‐range weather forecast errors in Europe

AbstractMineral dust, the most abundant atmospheric aerosol by mass, interacts with radiation directly and alters cloud properties indirectly. Many operational numerical weather prediction models account for aerosol direct effects by using climatological mean concentrations and neglect indirect effects. This simplification may lead to shortcomings in model forecasts during outbreaks of Saharan dust towards Europe, when climatological mean dust concentrations deviate strongly from actual concentrations. This study investigates errors in model analyses and short‐range forecasts during such events. We investigate a pronounced dust event in March 2021 using the pre‐operational ICOsahedral Nonhydrostatic weather and climate model with Aerosols and Reactive Trace gases (ICON‐ART) with prognostic calculation of dust and the operational European Centre for Medium‐Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS) model, which deploys a dust climatology. We compare model analysis and forecast with measurements from satellite and in situ instruments. We find that inclusion of prognostic aerosol and direct radiative effects from dust improves forecasts of surface radiation during clear‐sky conditions. However, dust‐induced cirrus clouds are strongly underestimated, highlighting the importance of representing indirect effects adequately. These findings are corroborated by systematic quantification of forecast errors against satellite measurements. For this we construct an event catalogue with 49 dust days over Central Europe between January 2018 and March 2022. We classify model cells by simulated and observed cloudiness and simulated dustiness in the total atmospheric column. We find significant overestimations of brightness temperature for cases with dust compared with cases without dust. For surface shortwave radiation, we find median overestimations of 6.2% during cloudy conditions with dust optical depth greater than 0.1, however these are not significant compared with cloudy conditions without dust. Our findings show that the pre‐operational ICON‐ART and the operational IFS model still do not reproduce cloudiness adequately during events with Saharan dust over Central Europe. Missing implementations of prognostic dust, particularly of indirect effects on cloud formation, lead to significant underestimations of cloudiness and potentially overestimations of surface radiation.

Potential of Transthoracic Echocardiography and Cardiac CT in Pulmonary Arteries Assessment in Children With Pulmonary Atresia With Ventricular Septal Defect

Objective: To assess and compare the potential of transthoracic echocardiography (TTE) and cardiac computed tomography (CT) in determining severity of pulmonary artery hypoplasia in children with pulmonary atresia with ventricular septal defect (PA-VSD) during preoperative planning.Materials and methods: The study included 38 children (mean age, 1.5 years; 97% of the patients younger than 1 year) with a clinical diagnosis of PA-VSD. All the patients underwent TTE; 36 of them underwent cardiac CT, while 33 children had direct angiocardiography. During all diagnostic methods we performed morphometry of the pulmonary trunk (if any) and proximal and distal parts of right and left pulmonary arteries, calculated z score for every vessel, Nakata index, and McGoon ratio. All the results were compared with fiof direct angiography and/or intraoperative data. The interval between TTE, cardiac CT, and angiocardiography or open surgery was less than 10 days. The criterion for hypoplasia of the pulmonary artery and its branches was z score deviation less than (−2) from reference values. Nakata index less than 200 mm2/m2 and McGoon ratio less than 1.0 were considered contraindications for radical correction.Results: We found no statistically significant difference (P > .05) when comparing the potential of TTE and cardiac CT with direct angiography/intraoperative data in terms of morphometry of the proximal parts of the right and left pulmonary arteries and calculating z scores. All the methods demonstrated high diagnostic efficacy. We found statistically significant differences when comparing the potential of TTE and cardiac CT in pulmonary trunk angiometry: the results of pulmonary trunk measurement using TTE were statistically significantly different from the findings of cardiac CT and angiography/intraoperative data with significant underestimation of vessel diameters (P < .05). The results of measurements of the distal parts of the pulmonary artery using TTE were statistically significantly different from those of cardiac CT and direct angiography/intraoperative data with significant underestimation of vessel diameters (P < .05). There were no statistically significant differences between CT and direct angiography/intraoperative data in assessing the diameters of the distal branches of the pulmonary artery. When assessing McGoon ratio and Nakata index using TTE, we found statistically significant differences (underestimation of values) in comparison with direct angiography (P < .05). Comparison of McGoon ratios measured by TTE and cardiac CT also demonstrated their statistically significant underestimation by TTE (P < .05). The calculated McGoon ratio during cardiac CT did not differ significantly from the direct angiography findings.Conclusions: TTE cannot be considered the final method for preoperative assessment of the pulmonary artery system development in children with PA-VSD due to the limited visualization of the distal parts of the right and left pulmonary arteries and significant underestimation of the pulmonary trunk diameter and indices. Cardiac CT proved its high effectiveness in assessment of hypoplasia severity and can be an alternative to direct angiography.

137 Impacts of heat stress on the accuracy of an ear-tag sensor for detection of eating and rumination behavior in cattle

Abstract Ear-tag accelerometers are used for precision livestock management, but little is known regarding effects of varying environmental conditions on sensor performance. The objective was to evaluate accuracy of a commercially available ear-tag sensor (CowManager SensOor, Agis Automatisering BV, Harmelen, the Netherlands) in quantifying feeding behaviors under varying temperature-humidity indices (THI). RumiWatch System (RW) noseband sensors (Itin+Hoch GmbH, Liestal, Switzerland) were utilized as a benchmark. Nine Holstein-Angus steers (body weight: 488 ± 9 kg) were fitted with CowManager (CM) sensors and RW halters, with continuous monitoring during two 14-d phases: thermoneutral (TN: 21.0 ˚C, 64.0% humidity, THI = 67) and heat stress (HS: cyclical daily temperatures to mimic diurnal patterns; HS: 23.2 ˚C – 33.6 ˚C, 39.5 – 70.0% humidity, THI = 70.3 – 83.5). Steers were individually-housed (3×3 m) and provided ad libitum access to a mixture of corn silage and dried distillers grains with solubles. Hourly summaries of eating time (ET) recorded by CM were compared with EAT1TIME (head down) and EAT2TIME (head up) parameters from RW (v.7.3.36) as well as total ET (EAT1TIME + EAT2TIME); rumination time (RT) was also compared. Agreement was evaluated (R; v.4.3.1) over the full 24-h day (FULL) and a 6-h period from afternoon to early evening (AFT; 1400 – 2000 h) when HS effects would be most pronounced. Across both 14-d phases, agreement between CM and EAT1TIME was moderate to high (concordance correlation coefficient [CCC] = 0.69 to 0.77), whereas agreement with EAT2TIME and total ET was poor to moderate (CCC = 0.41 – 0.61). Bland-Altman analysis demonstrated significant underestimation of total ET by CM, with biases of -8.98 (-10.88, -7.09) to -6.44 (-7.51, -5.38) min h-1. Agreement for EAT1TIME was high for TN (CCC = 0.74), but only moderate during HS (CCC = 0.69) for the FULL dataset. Similarly, agreement for total ET was moderate for TN but poor for HS over FULL and during AFT, respectively (CCC: TN – 0.53, 0.54; HS – 0.47, 0.41). CowManager significantly underestimated EAT1TIME during HS (bias: FULL = -1.45 [-2.60, -0.30]; AFT = -2.14 [-3.93, -0.35] min h-1), but not TN (bias: FULL = -1.38 [-2.82, 0.06]; AFT = -1.83 [-3.68, 0.02] min h-1). Agreement for RT was high regardless of environmental conditions and time period analyzed (CCC = 0.74 – 0.81). However, during the critical AFT period, CM significantly overestimated RT under HS (bias: 4.42 [2.06, 6.79] min h-1) but not TN conditions (bias: -0.47 [-2.42, 1.47] min h-1). These results indicate that ET reported by CM is more reflective of time eating with the head down than the total time engaged in eating behaviors. Results of this study also suggest accuracy of ear-tag accelerometers may be impaired when cattle are subjected to heat stress.

Avaliação visual do índice de área foliar em campos de café (Coffea arabica L.)

ABSTRACT The application of leaf area index (LAI) in coffee crop management depends on the availability of methodologies for proper estimation. The objective of this study was to develop a methodology for the visual assessment of LAI in coffee fields and to establish a protocol for training, evaluation, and feedback for evaluators. Four rounds of LAI measurements were conducted using visual estimates, two instruments (LAI 2200-C and AccuPAR LP-80), and defoliation of coffee hedgerows in Poás, Costa Rica. In each round, five workers visually estimated the LAI values on two occasions separated by 15 days, and feedback reinforcement was provided to each worker at the end of each round. Visual assessments showed high repeatability and reproducibility and the estimates were adjusted to the linear regression model in most cases. Evaluators improved their capacity to visually assess the LAI throughout the rounds, as the value of R2increased consistently for most workers, with values as high as 0.87. Instrumentation evaluation of LAI produced R2values of 0.5-0.6, with significant underestimation bias. The performance of the different methods is discussed in the context of widely spaced hedgerows. The proposed visual methodology constitutes a statistically sound, rapid, simple, and reliable method for determining the LAI of coffee fields to aid in decision-making for crop management.

Comparative Study of O3 Forecast Performance Using Multiple Models in Beijing–Tianjin–Hebei and Surrounding Regions

In order to systematically understand the operational forecast performance of current numerical, statistical, and ensemble models for O3 in Beijing–Tianjin–Hebei and surrounding regions, a comprehensive evaluation was conducted for the 30 model sets regarding O3 forecasts in June–July 2023. The evaluation parameters for O3 forecasts in the next 1–3 days were found to be more reasonable and practically meaningful than those for longer lead times. When the daily maximum 8 h average concentration of O3 was below 100 μg/m3 or above 200 μg/m3, a significant decrease in the percentage of accurate models was observed. As the number of polluted days in cities increased, the overall percentage of accurate models exhibited a decreasing trend. Statistical models demonstrated better overall performance in terms of metrics such as root mean square error, standard mean bias, and correlation coefficient compared to numerical and ensemble models. Numerical models exhibited significant performance variations, with the best-performing numerical model reaching a level comparable to that of statistical models. This finding suggests that the continuous tuning of operational numerical models has a more pronounced practical effect. Although the best statistical model had higher accuracy than numerical and ensemble models, it showed a significant overestimation when O3 concentrations were low and a significant underestimation when concentrations were high. In particular, the underestimation rate for heavy polluted days was significantly higher than that for numerical and ensemble models. This implies that statistical models may be more prone to missing high-concentration O3 pollution events.

Designs of the divider and special multiplier optimizing T and CNOT gates

Quantum circuits for multiplication and division are necessary for scientific computing on quantum computers. Clifford + T circuits are widely used in fault-tolerant realizations. T gates are more expensive than other gates in Clifford + T circuits. But neglecting the cost of CNOT gates may lead to a significant underestimation. Moreover, the small number of qubits available in existing quantum devices is another constraint on quantum circuits. As a result, reducing T-count, T-depth, CNOT-count, CNOT-depth, and circuit width has become the important optimization goal. We use 3-bit Hermitian gates to design basic arithmetic operations. Then, we present a special multiplier and a divider using basic arithmetic operations, where ‘special’ means that one of the two operands of multiplication is non-zero. Next, we use new rules to optimize the Clifford + T circuits of the special multiplier and divider in terms of T-count, T-depth, CNOT-count, CNOT-depth, and circuit width. Comparative analysis shows that the proposed multiplier and divider have lower T-count, T-depth, CNOT-count, and CNOT-depth than the current works. For instance, the proposed 32-bit divider achieves improvement ratios of 40.41 percent, 31.64 percent, 45.27 percent, and 65.93 percent in terms of T-count, T-depth, CNOT-count, and CNOT-depth compared to the best current work. Further, the circuit widths of the proposed n-bit multiplier and divider are 3n. I.e., our multiplier and divider reach the minimum width of multipliers and dividers, keeping an operand unchanged.

The Effects of Physical and Mental Fatigue on Time Perception.

The perception of time holds a foundational significance regarding how we elucidate the chronological progression of events. While some studies have examined exercise effects on time perception during exercise periods, there are no studies investigating the effects of exercise fatigue on time perception after an exercise intervention. This study investigated the effects of physical and mental fatigue on time estimates over 30 s immediately post-exercise and 6 min post-test. Seventeen volunteers were subjected to three conditions: physical fatigue, mental fatigue, and control. All participants completed a familiarization session and were subjected to three 30 min experimental conditions (control, physical fatigue (cycling at 65% peak power output), and mental fatigue (Stroop task)) on separate days. Time perception, heart rate, and body temperature were recorded pre-test; at the start of the test; 5, 10, 20, 30 seconds into the interventions; post-test; and at the 6 min follow-up. Rating of perceived exertion (RPE) was recorded four times during the intervention. Physical fatigue resulted in a significant (p = 0.001) underestimation of time compared to mental fatigue and control conditions at the post-test and follow-up, with no significant differences between mental fatigue and control conditions. Heart rate, body temperature, and RPE were significantly (all p = 0.001) higher with physical fatigue compared to mental fatigue and control conditions during the intervention and post-test. This study demonstrated that cycling-induced fatigue led to time underestimation compared to mental fatigue and control conditions. It is crucial to consider that physical fatigue has the potential to lengthen an individual's perception of time estimates in sports or work environments.

Prediction of the weighted-mean soil water diffusivity in supporting the falling rate stage of evaporation

Daily soil evaporation from drying soil can be described as isothermal linear diffusion process, resulting in a simple equation for estimating soil evaporation rate. However, determining soil water diffusivity and subsequently the crucial parameter of weighted-mean diffusivity, essential for estimating soil evaporation rate, is challenging and time-consuming. In this paper, the soil water diffusivity was re-evaluated by considering the effect of film flow, a phenomenon often overlooked but recently argued by Wang et al. (2019, https://doi.org/10.1029/2019WR025003) as the dominant process in the falling rate stage of evaporation. Theoretical derivation reveals a universal relationship between soil water diffusivity and matric potential, independent of soil types. Additionally, soil water diffusivity can be expressed in the form of an exponential function, a form commonly assumed empirically in the literature. Testing with various datasets suggests that the theoretically derived soil water diffusivity generally agrees closely with observations for matric potentials less than about −1 m, wherein the diffusivity accounting for capillary flow shows significant underestimation. Furthermore, a simple function is derived for estimating the weighted-mean diffusivity, enabling a direct estimation of soil evaporation rates in the falling rate stage. Testing with various data sets of different soil types and ambient conditions generally demonstrates close agreements between the estimated soil evaporation rates and observations, indicating that the developed method provides a robust estimation of the weighted-mean soil water diffusivity. When the initial matric potential of the linear diffusion process of drying is higher than about −1 m, which usually occurs under very high atmospheric demand conditions or for very coarse-textured soils, however, the effects of capillary flow were found to be important and need consideration. The effects of vapor diffusion were also discussed and found to have a negligible impact on the estimation of weighted-mean soil water diffusivity.

Effects of brightness variations on a smartphone-based version of Radner reading charts.

The purpose of this study was to evaluate the equivalence of smartphone-based measurements of near visual acuity under different screen brightness conditions with a standard near visual acuity test. On a sample of 85 participants, we have evaluated near visual acuity with a smartphone-based version of the Radner reading chart at three distinct screen brightness levels. Results have been compared with those obtained with classical Radner paper charts. We have found that, when a sufficient screen brightness is employed, the smartphone-based version of the Radner reading chart produces results that are in line with the paper Radner charts while low brightness levels lead to a significant underestimation of reading acuities. This result was consistent across different refractive conditions. In conclusion, we have shown that handheld devices, such as smartphones, can be potentially exploited for remote measurements of near visual acuity provided a correct control of brightness screen is employed.

Quality control of instruments for measuring the characteristics of bactericidal UV radiation

Objectives. Quality control of instruments for measuring bactericidal irradiance of ultraviolet (UV) radiation is based on studying the main metrological characteristics. These characteristics include: angular and spectral sensitivity; linearity range; and absolute calibration in irradiance units. Deviations of the angular sensitivity of measuring instruments from the ideal cosine characteristic can significantly impact error estimation. They can also lead to the distortion of measurement results and a significant difference in instrument readings. The aim of this work is to enhance accuracy in resolving metrological problems of determining irradiance of bactericidal radiation.Methods. An effective method of resolving this problem is to introduce correction coefficients for the angular sensitivity of radiometers, spectroradiometers and dosimeters. The values are calculated based on the results of measurements on the goniometer when testing measuring instruments. An important role is played by computer models and digital twins of measuring instruments based on the results of studies of the metrological characteristics of radiometers by means of software. This includes modeling the measuring task.Results. The study of angular dependence of bactericidal UV radiometer sensitivity complemented by an analysis of measurement results obtained by other authors allows determining the value of the angular sensitivity correction coefficients by the deviation of the angular sensitivity of the irradiance measuring instruments of bactericidal radiation from the standard cosine dependence.Conclusions. Deviations of the angular dependence of bactericidal radiation UV radiometer sensitivity from the cosine characteristic lead to a significant underestimation of the irradiance measurements results from extended emitters. An effective solution is the use of digital angular sensitivity correction coefficients to measure the irradiance of bactericidal radiation determined during tests. When assessing the quality of radiometers, spectroradiometers and dosimeters for bactericidal radiation, incomplete control of the main metrological characteristics of the measuring instruments creates risks of serious errors in the measurement results of bactericidal irradiance.

Significant Oxygen Underestimation When Quantifying Barium-Doped SrTiO Layers by Atom Probe Tomography.

In this paper, the capability for quantifying the composition of Ba-doped SrTiO layers from an atom probe measurement was explored. Rutherford backscattering spectrometry and time-of-flight/energy elastic recoil detection were used to benchmark the composition where the amount of titanium was intentionally varied between samples. The atom probe results showed a significant divergence from the benchmarked composition. The cause was shown to be a significant oxygen underestimation (≳14 at%). The ratio between oxygen and titanium for the samples varied between 2.6 and 12.7, while those measured by atom probe tomography were lower and covered a narrower range between 1.4 and 1.7. This difference was found to be associated with the oxygen and titanium predominantly field evaporating together as a molecular ion. The evaporation fields and bonding chemistries determined showed inconsistencies for explaining the oxygen underestimation and ion species measured. The measured ion charge state was in excellent agreement with that predicted by the Kingham postionization theory. Only by considering the measured ion species, their evaporation fields, the coordination chemistry, the analysis conditions, and some recently reported density functional theory modeling for oxide field emission were we able to postulate a field emission and oxygen neutral desorption process that may explain our results.

Evaluating Prognostic Bias of Critical Illness Severity Scores Based on Age, Sex, and Primary Language in the United States: A Retrospective Multicenter Study.

Although illness severity scoring systems are widely used to support clinical decision-making and assess ICU performance, their potential bias across different age, sex, and primary language groups has not been well-studied. We aimed to identify potential bias of Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) IVa scores via large ICU databases. This multicenter, retrospective study was conducted using data from the Medical Information Mart for Intensive Care (MIMIC) and eICU Collaborative Research Database. SOFA and APACHE IVa scores were obtained from ICU admission. Hospital mortality was the primary outcome. Discrimination (area under receiver operating characteristic [AUROC] curve) and calibration (standardized mortality ratio [SMR]) were assessed for all subgroups. Not applicable. A total of 196,310 patient encounters were studied. Discrimination for both scores was worse in older patients compared with younger patients and female patients rather than male patients. In MIMIC, discrimination of SOFA in non-English primary language speakers patients was worse than that of English speakers (AUROC 0.726 vs. 0.783, p < 0.0001). Evaluating calibration via SMR showed statistically significant underestimations of mortality when compared with overall cohort in the oldest patients for both SOFA and APACHE IVa, female patients (1.09) for SOFA, and non-English primary language patients (1.38) for SOFA in MIMIC. Differences in discrimination and calibration of two scores across varying age, sex, and primary language groups suggest illness severity scores are prone to bias in mortality predictions. Caution must be taken when using them for quality benchmarking and decision-making among diverse real-world populations.

The effects of the velocity distribution of impact generated water ice ejecta on exospheric escape from airless bodies

We explore the velocity distribution of impact generated water ice ejecta from planetary surface. We show that the ejecta velocity distribution should be modeled by a mixed Maxwellian distribution, rather than the commonly used single Maxwellian distribution, in order to better capture the outcome of the different emission processes and the dynamics of the clustered water molecules in the ejecta. We find that, comparing to the mixed Maxwellian distribution, the single Maxwellian distribution may lead to a significant underestimation of the impact-ejected water molecules that stay gravitationally bound for exosphere models. While the relative difference is within 10% for celestial bodies with a large escape velocity such as Mercury, it can be about 1000% for celestial bodies with a small escape velocity such as Enceladus.

Soil pore water evaporation and temperature influences on clay mineral paleothermometry

Clay mineral isotope paleothermometry is fundamental to understanding Earth’s climate system and landscape evolution. Status quo methods, however, assume constant factors, such as formation temperature and water isotopic compositions, and ignore seasonality, soil water evaporation and depth-dependent temperature changes. We propose first-order modifications to address these factors and test them in a modeling framework using published data from various settings. Our forward model reveals that neglecting evaporation and seasonal soil temperature variability may lead to significant underestimations of clay formation temperatures, especially in Mediterranean settings. Our inverse model indicates that high-latitude Eocene clay formation temperatures were ~8 °C warmer than modern, while Eocene river sediments in the Sierra Nevada show evaporation-influenced trends, suggesting that previous paleoelevation estimates were underestimated. Our framework demonstrates that explicit consideration of soil pore water evaporation and temperature variability is necessary when interpreting clay mineral isotope data in the context of temperature, hydroclimate and elevation reconstructions.

Electrochemical Probing the Site Reactivity in Iron Single-Atom Catalysts for Electrocatalytic Nitrate Reduction to Ammonia.

Single-atom catalysts (SACs), specifically iron single atoms dispersed on nitrogen-doped carbon (Fe-NC), have shown promising potential in the electrocatalytic reduction of nitrate to ammonia (NitRR), but there is a lack of understanding of their intrinsic activity. The conventional measurements often overlook the intrinsic performance of SACs, leading to significant underestimation. This study presents an in situ electrochemical probing protocol, using two poisoning molecules (SCN- and NO2-), to characterize the reactivity of Fe sites in Fe-NC SACs for NitRR. The technique aids in quantifying the yield rate of ammonia on Fe sites and the active site number. The findings reveal the intrinsic turnover frequency (TOF) based on the number and ammonia yield rate of Fe sites, challenging the current understanding of SACs' inherent performances. This unique approach holds considerable potential for determining the intrinsic activity of other SACs in complex reactions, opening new avenues for the exploration of electrocatalytic processes.

An analytical model for thermoelastic crack problems in a strip incorporating convective heat transfer between lateral surfaces and ambient environment

Most existing thermoelastic crack models commonly overlook the convective heat exchange occurring on the lateral surfaces of the structures being studied. Consequently, there is often a concern regarding the accurate estimation of temperature fields and the resulting thermal stresses. To address this concern, this paper presents a two-dimensional (2D) thermoelastic model for a cracked strip that incorporates convective heat transfer between the lateral surfaces and the ambient environment. The crack problem is reduced to a set of singular integral equations with Cauchy kernels which are solved numerically. Analytical solutions for temperature distribution, stress intensity factors (SIFs) and energy release rate at crack tips are obtained. The influence of the ratios of convective heat transfer coefficient to thermal conductivity and thickness to height of the strip on the key fracture parameters is investigated through the numerical results. It has been discovered that classical thermoelastic crack models often exhibit a significant underestimation of the SIFs and energy release rates for cracks located near the hot boundary of the strip. The analytical model proposed in this paper has significant potential to advance our understanding of thermoelastic fracture mechanics.

The accuracy of core needle biopsy in determining histological type and Scarf-Bloom-Richardson grade in invasive breast cancer

Core needle biopsy provides information not only on the histological diagnosis but also about tumor grade and different prognosis factors for breast cancer. This study was designed to determine the accuracy of percutaneous core needle biopsy (CNB) through comparative analysis of histological diagnosis and SBR tumor grade of invasive breast cancer between CNB and surgical excision specimen (SES). This was a retrospective cross-sectional study from January 2023 to July 2023. All patients with invasive breast cancer diagnosed by CNB and confirmed by surgical excision specimen (SES) examination were included in the study. Patients who received neoadjuvant chemotherapy were excluded. One twenty-three patients were assessed. All patients were female. The median age was 45 years (37 – 54). Invasive ductal carcinoma (IDC) was the major histological type of breast cancer (95.1%) followed by invasive lobular carcinoma (ILC) (4.9%). SBR grade 2 tumors accounted for 78.1% of cases. The majority of patients presented with locally advanced stage breast cancer (65.9%) or a metastatic disease (31.7%). Concordance for histological type was substantial (k= 0.79; p&amp;#60;0,001) whereas it was moderate (k= 0.45; p&amp;#60;0,001) for Scarf-Bloom-Richardson grade. Histological type on CNB correlates almost perfectly with that of the surgical excisional specimen in case of breast cancer. Nevertheless, the agreement of tumor grade between CNB and SES remains moderate, with a significant underestimation and overestimation rates.

Global impacts of vegetation clumping on regulating land surface heat fluxes

The clumping index (CI) quantifies the non-random distribution of vegetation across space, which regulates the canopy radiative transfer processes and land surface carbon, water, and energy cycles. However, its impact on global surface energy budget, particularly sensible heat fluxes and surface temperature, is not well understood. Additionally, while there have been studies showing significant seasonal variations in CI, the impacts of these variations on surface energy fluxes remain unclear. In this study, we incorporated satellite-derived spatially and temporally explicit CI data into the Community Land Model version 5 (CLM5) to evaluate the effects of CI on global land energy fluxes. Our results showed that including CI increased the global mean sensible heat flux dissipated from ground by 3.9 W m−2 (∼18%), while decreasing the global mean vegetation sensible heat flux by 4.9 W m−2 (∼65%), resulting in a total sensible heat decrease of 1.0 W m−2 (∼3%). In contrast, CI increased the global mean latent heat flux by 0.8 W m−2 (∼2%), primarily due to increased evapotranspiration (up to 11 W m−2) in tropical regions. We also found considerable impacts of seasonal variations in CI, particularly on sensible heat fluxes from ground and vegetation in evergreen needleleaf forests and deciduous needleleaf forests. Using constant CI rather than considering seasonal variations resulted in significant overestimation and underestimation of the sensible heat fluxes from vegetation and ground, respectively, in boreal summer. These changes in surface energy fluxes caused by CI and its seasonal variations led to up to 1.7 and 0.5 K differences in simulated mean ground temperature. These findings highlight the importance of including CI and considering its seasonal variations in modeling land surface energy fluxes.