Slope Of Line Research Articles

A Yoga Pose Difficulty Level Estimation Method Using OpenPose for Self-Practice System to Yoga Beginners

Yoga is an exercise preferable for various users at different ages to enhance physical and mental health. To help beginner yoga self-practitioners avoid getting injured by selecting difficult yoga poses, the information of the difficulty level of yoga poses is very important to provide an objective metric to assist yoga self-practitioners in selecting appropriate exercises on the basis of their skill level by using the yoga self-practice system. To enhance the developed yoga self-practice system, the yoga difficulty level estimation function will enable users to clearly understand whether the selected yoga poses are suitable for them. In this paper, the newest difficulty level estimation method of yoga poses is proposed by using and analyzing OpenPose two-dimensional (2D) human body keypoints. The proposed method effectively uses the selected six keypoints areas of the upper and lower body, body support types, center of gravity calculations, and body tilt angles and slopes to produce estimations. Firstly, the method calculates the weighted centers of the upper and lower human body for each pose by using keypoints. Secondly, it refers the slope of the centroid line between the two centers and infers the body’s balance state. Lastly, the system estimates the difficulty level by additionally considering the keypoints of the body to contact the ground. For evaluations of the proposal, more than one hundred yoga poses are collected from the Internet and applied to classify them into five difficulty levels. Through comparisons with subjective levels from one instructor and 10 users, the validity of the estimation results is confirmed, a comparison is performed with existing designs, and it is implemented in embedded systems.

Effect of the Cross-Sectional Geometry of the Mixed Particle Zone on the Spiral Separation Process and Its Structural Optimization

Cross-sectional geometry is of significance in determining the flow characteristics and the particles separation in spiral concentrators. The effects of the cross-sectional geometry within the mixed particle zone on the secondary flow and the separation process of hematite and quartz particles with a size of 89.5 μm were investigated via a computational fluid dynamics (CFD) approach. The optimization of the line segment slopes was conducted using response surface methodology (RSM). The results indicate that the peak radial fluxes and average radial velocities of the secondary flow are positively correlated with the corresponding line segment slope. The independent adjustment of line slopes in regions Ⅰ and Ⅱ, and the interaction of line slopes in regions Ⅰ and Ⅲ, influence the separation efficiency of hematite and quartz particles significantly. The separation performance of the experimental spiral concentrator with a cross-sectional profile of the optimized line segments for a feed of hematite and quartz with a size range of -100+75 μm is remarkably improved by nearly 5%. This study provides insights for the cross-section design of spiral concentrators for the effective separation of coarse-grained hematite and quartz.

Assessing the Accuracy of Cardiovascular Disease Prediction Using Female-Specific Risk Factors in Women Aged 45 to 69 Years in the UK Biobank Study.

Cardiovascular disease (CVD) is the leading cause of mortality in women. We aimed to assess whether adding female-specific risk factors to traditional factors could improve CVD risk prediction. We used a cohort of women from the UK Biobank Study aged 45 to 69 years, free of CVD at baseline (2006-2010) followed until the end of 2019. We developed Cox proportional hazards models using the risk factors included in 3 contemporary CVD risk calculators: Pooled Cohort Equation - Atherosclerotic Cardiovascular Disease, Qrisk2, and PREDICT. We added each of the following female-specific risk factors, individually and all together, to determine if these improved measures of discrimination and calibration for predicting CVD: early menarche (<11 years), endometriosis, excessive, frequent or irregular menstruation, miscarriage, number of miscarriages, number of stillbirths, infertility, preeclampsia or eclampsia, gestational diabetes (without subsequent type 2 diabetes), premature menopause (<40 years), early menopause (<45 years), and natural or surgical early menopause (menopause <45 years or timing of menopause reported as unknown and oophorectomy reported at age <45). In the model of 135 142 women (mean age, 57.5 years; SD, 6.8) using risk factors from Pooled Cohort Equation - Atherosclerotic Cardiovascular Disease, CVD incidence was 5.3 per 1000 person-years. The c-indices for the Pooled Cohort Equation - Atherosclerotic Cardiovascular Disease, Qrisk2, and PREDICT models were 0.710, 0.713, and 0.718, respectively. Adding each of the female-specific risk factors did not improve the c-index, the net reclassification index, the integrated discrimination index, the slope of the regression line for predicted versus observed events, and the Brier score or plots of calibration. Adding all female-specific risk factors simultaneously increased the c-index for the Pooled Cohort Equation - Atherosclerotic Cardiovascular Disease, Qrisk2, and PREDICT models to 0.712, 0.715, and 0.720, respectively. Although several female-specific factors have been shown to be early indicators of CVD risk, these factors should not be used to reclassify risk in women aged 45 to 69 years when considering whether to commence a blood pressure or lipid-lowering medication.

Silicon Isotopic Composition of Mainstream Presolar SiC Grains Revisited: The Impact of Nuclear Reaction Rate Uncertainties

Abstract Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable probes of these astrophysical sites. The most common types of presolar silicon carbide grains (called mainstream SiC grains) condensed in the outflows of asymptotic giant branch stars. Their measured silicon isotopic abundances are not significantly influenced by nucleosynthesis within the parent star but rather represent the pristine stellar composition. Silicon isotopes can thus be used as a proxy for galactic chemical evolution (GCE). However, the measured correlation of 29Si/28Si versus 30Si/28Si does not agree with any current chemical evolution model. Here, we use a Monte Carlo model to vary nuclear reaction rates within their theoretical or experimental uncertainties and process them through stellar nucleosynthesis and GCE models to study the variation of silicon isotope abundances based on these nuclear reaction rate uncertainties. We find that these uncertainties can indeed be responsible for the discrepancy between measurements and models and that the slope of the silicon isotope correlation line measured in mainstream SiC grains agrees with chemical evolution models within the nuclear reaction rate uncertainties. Our result highlights the importance of future precision reaction rate measurements for resolving the apparent data–model discrepancy.

Relationships Among Capillary Refill Time, Peripheral Blood Flow Rate, and Fingertip Temperature: Advances in Peripheral Artery Contractility Diagnosis.

Capillary refill time (CRT) is a widely used noninvasive measure of cardiovascular health. Despite its widespread diagnostic utility, it has several limitations, particularly its low sensitivity for certain conditions, because factors such as the contraction and relaxation of distal blood vessels can influence CRT readings. This study was performed to explore the relationships between CRT and distal blood flow. The right hand of each of 10 healthy adult volunteers was cooled to induce blood vessel contraction. CRT, fingertip temperature, and blood flow rate were measured using a custom device, a thermometer, and a laser Doppler blood flow meter, respectively, before and after cooling. Hand cooling significantly decreased blood flow rate and increased CRT. A robust inverse correlation was observed between blood flow rate and CRT, supporting a model where CRT is the time required for blood to flow through a cylindrical pipe. Furthermore, CRT showed a significant negative correlation with fingertip temperature. Most participants had high correlation coefficients, although two showed lower values. However, all data points exhibited a linear relationship, with the slopes of the regression lines between CRT and temperature varying among participants. These results suggested that the slope between CRT and fingertip temperature indicates individual differences in arterial contractility. These findings could improve the diagnostic utility of CRT in assessing vascular health, including arterial age and Raynaud's phenomenon, based on the contractility of peripheral arteries.

Evaluation of the Seismicity Index for Nigerian Nuclear Installations

Seismic Hazard Assessment (SHA) is a quantitative measure of assessing the seismic hazard or risk involved for a given site. The parameter computed for such an assessment is needed for building engineers or national decision makers especially when it concerns nuclear installations. Even though the International Atomic Energy Agency (IAEA) currently makes it mandatory to provide such an index before undertaking any form of development or construction of a nuclear installation, this computation has not been done for Nigeria. Data over long period of time is usually necessary for a quantitative seismic hazard assessment, but because such information is scarce in Nigeria a fractal approach is therefore used in this research. A SHA index called the b-value is evaluated by determining the fractal dimension of the network of locations of recorded past tremor events within Nigeria. In this work a b-value of 0.43 which quantitatively measures the seismic hazard or risk of a given region is computed for Nigeria. Aeromagnetic data was used in producing analytic signal maps that accurately mapped faults that could have been responsible for causing the earth tremors, and the coordinates of these faults or lineament were used in calculating the fractal dimension of the system of faults. The fractal dimension of 0.8568 was obtained by determining the slope of line of best-fit of the plot of the log of the average number of tremor locations &lt;N(R)&gt; within radius R of each location against log of radius R, which was in turn used to determine the b-value. A b-value of 0.43 obtained indicates that Nigeria is in a less seismically active region and this can be used in the IAEA safety guidelines for nuclear installations.

A hysteretic water retention model incorporating the soil deformability and its application to rainfall-induced landslides

Traditional water retention models often overlook the dynamic interplay between soil structure and moisture content, leading to inaccurate predictions of unsaturated soil behaviors. In this research, based on laboratory data, van Genuchten’s soil water characteristic (van Genuchten, 1980) is modified to establish two bounding surfaces that define the permissible range of soil states in terms of the void ratio (e), suction (s), and degree of saturation (Sl). Considering a bounding surface technique, the model effectively captures hysteresis in the soil water retention behavior, encompassing main curves and scanning paths. This approach presumesthat within the permissible range of soil states, which is included between two main surfaces, the derivative of the degree of saturation by void ratio and suction relieson the soil state’s proximity to the main bounding surface. This hypothesis guarantees that the wetting–drying or compressing-swelling scanning curves transit smoothly toward their corresponding main surfaces. The derived equations for Sl are integrated into closed forms, allowing all scanning curves to be distinguished by varying values of the integration constant. Model necessitates the determination of two parameters (b and β) related to the slope and intercept of the linear line interpolating experiments in the ln(s)-ln(eSl/s) plane, which can be defined based on at least a single wetting–drying test. The model predictions are validated against various data sets, including sands and clayey soils, published in the literature. This validation demonstrates the model’s ability to reflect the behavior observed in experimental tests accurately. This new technique offers a significant advantage in the simplicity of parameter determination. Finally, this hysteretic water retention procedure is implemented into a finite element program (Code_Bright), and its performance is evaluated by simulating the behavior of a representative slope subjected to rainfall conditions.

Codon Usage Pattern and its Influencing Factors for Mitochondrial CO Genes Among Different Subfamilies of Cerambycidae.

This study examined nucleotide composition and codon usage of mitochondrial CO (cytochrome oxidase) genes from four subfamilies of Cerambycidae. Nucleotide composition analysis of the CO genes revealed an AT-rich pattern in the four subfamilies of Cerambycidae. Furthermore, by analyzing the correlation between the overall nucleotide composition of CO genes and the nucleotide composition of the 3rd codon, we found that mutation pressure and natural selection were the key factors affected the CUB. The regression of GC12 (The average of GC content of the entire gene first and second codon positions) vs GC3 (GC content of the entire gene third codon positions) scattered to a limited value, and all CO genes slope of the regression line was all less than 0.5, indicated that natural selection might have played a significant role in shaping the codon usage bias. ENC plot analysis further supported the predominant influence of natural selection on CUB, aligning with the findings from neutral plot analyses. These novel insights into the codon evolution of CO genes within Cerambycidae significantly contribute to our understanding of codon evolution.

The effect of distance on audiovisual temporal integration in an outdoor virtual environment

In this study, we explore the influence of stimulus distance on human tolerance for (physical) asynchronies in virtual reality (VR). A repeated audiovisual (AV) stimulus with sound and light bursts was presented to the participants in an outdoor virtual environment (VE) using a head-mounted display (HMD). The investigation focused on quantifying the point of subjective simultaneity (PSS) for both visual and auditory stimuli. A synchrony judgment method (SJ-3) was used for 11 stimulus onset asynchronies (SOA) and five egocentric distances from 10 m up to 50 m with 10 m increments. The data analysis showed negative PSS values that decreased with distance, resulting in a negative slope (-3 ms/m) of the regression line between PSS values and simulated distances. In contrast to the recent study conducted in the indoor VE, we conclude that the presented study in the outdoor VE does not incorporate a distance compensation mechanism and refutes the hypothesis of an ‘implicit estimation’ of sound-arrival time. The reasons behind the observed contrast are discussed in this paper. Moreover, the negative slope of the regression line (−3 ms/m) is similar to previous research, concluding that there is a temporal integration of auditory-visual information within human neural processes without distance compensation.

Water Transformation Relationship in Inner Mongolia Section of the Yellow River Basin Based on Stable Hydrogen and Oxygen Isotopes

By collecting the atmospheric precipitation, surface water, and groundwater in the Inner Mongolia section of the Yellow River Basin in July 2021 （wet season）, October （normal season）, and April 2022 （dry season）, stable isotope technology was used to analyze the temporal and spatial changes in hydrogen and oxygen stable isotopes in the "three rivers" of the basin, and the MixSIAR mixing model was used to reveal the water body transformation relationship. The results showed that the mean difference in the groundwater isotope was small in the abundance period, flat period, and dry period in the Mongolia section of the Yellow River Basin. The groundwater regeneration was slow, the retention time was long, the seasonal variation was not obvious, and the δD value of surface water was higher in the abundance period than in the normal period and dry period. According to the δ18O and δD diagrams, the slope and intercept of surface water lines in the three periods were smaller than those of local precipitation lines, and surface water was affected by evaporative fractionation after receiving precipitation recharge. The δD values of surface water on the north bank of the Yellow River showed a trend of first increasing and then decreasing from upstream to downstream, while the δD values of surface water on the south bank of the Yellow River showed a trend of gradually decreasing from upstream to downstream. The recharge contribution of groundwater in surface water in the high-water period accounted for 2.9%, precipitation accounted for 97.1%, surface water accounted for 5.0%, atmospheric precipitation accounted for 95.0%, surface water accounted for 56.6%, and precipitation accounted for 43.4%, and the recharge contributions of precipitation and surface water to groundwater in the high water period were 47.6% and 52.4%, respectively. Those in the normal period were 30.7% and 69.3%, and those in the dry period were 37.8% and 62.2%, respectively. Atmospheric precipitation was the main replenishment source of surface water, showing that the replenishment ratio in the wet season was larger than that in the normal season and dry season, which was closely related to the total precipitation and its distribution in each period. Surface water was the main replenishment source of groundwater, showing that dry season &gt; normal season &gt; wet season.

The dynamic range of immunoassays for heparin-induced thrombocytopenia

BackgroundFollowing the current guidelines, immunoassays for the diagnosis of heparin-induced thrombocytopenia (HIT) are interpreted dichotomously, with test results categorized as either positive or negative. However, the extent to which test results hold diagnostic significance across the entire dynamic range remains unclear. ObjectivesWe utilized data from the prospective TORADI-HIT study, comprising 1,393 consecutive patients with suspected HIT, to assess the diagnostic significance of two H/PF4 immunoassay test results across their respective dynamic ranges: HemoSil Acustar HIT IgG [CLIA] and Lifecodes PF4 IgG [ELISA]. MethodsHIT diagnosis was determined by a washed-platelet heparin-induced platelet activation assay (HIPA). For each measurement point in the dataset, we computed likelihood ratios (LR), sensitivities, and specificities. To provide post-test probabilities for individual test results, we calculated interval-specific likelihood ratios and integrated it into a web-based calculator. ResultsThe prevalence of HIT was 8.5% (n = 119). A likelihood ratio of ≥ 10 was first achieved at 0.3% of the dynamic range (0.4 U/ml; CLIA) and 16% (0.64 OD; ELISA), respectively. A likelihood ratio of ≥ 100 was present at 9.4% (12 U/ml; CLIA) and 75.0% (3.0 OD; ELISA). The slope of the linear regression line (LR ∼ dynamic range) was 9.5 (CLIA) and 0.9 (ELISA). ConclusionDespite both immunoassays showing an association between results and diagnostic significance, the strength of that association varies by assay. CLIA has a larger increase per measurement unit. Post-test probabilities for individual patients can be estimated using a web-based calculator: https://pcd-research.shinyapps.io/BayesianCalculator/.

Groundwater Geochemistry in the Karst-Fissure Aquifer System of the Qinglian River Basin, China

The Qinglian River plays a significant role in China’s national water conservation security patterns. To clarify the relationship between hydrogeochemical properties and groundwater quality in this karst-fissure aquifer system, drilling data, hydrochemical parameters, and δ2H and δ18O values of groundwater were analyzed. Multiple indications (Piper diagram, Gibbs diagram, Na+-normalized molar ratio diagram, chloro-alkaline index 1, mineral saturation index, and principal component analysis) were used to identify the primary sources of chemicals in the groundwater. Silicate weathering, oxidation of pyrite and chlorite, cation exchange reactions, and precipitation are the primary sources of dissolved chemicals in the igneous-fissure water. The most relevant parameters in the karst water are possibly from anthropogenic activities, and other chemicals are mostly derived from the dissolution of calcite and dolomite and cation exchange reactions. Notably, the chemical composition of the deep karst water from the karst basin is mainly influenced by the weathering of carbonate and cation exchange reactions and is less affected by human activities. The hydrogeochemical properties of groundwater in the karst hyporheic zone are influenced by the dissolution of carbonates and silicates, evaporation, and the promotion effect of dissolution of anorthite or Ca-containing minerals. Moreover, the smallest slope of the groundwater line from the karst hyporheic zone among all groundwater groups revealed that the mixing effects of evaporation, isotope exchange in water–rock interaction or deep groundwater recharge in the karst hyporheic zone are the strongest. The methods used in this study contribute to an improved understanding of the hydrogeochemical processes that occur in karst-fissure water systems and can be useful in zoning management and decision-making for groundwater resources.

The Application of Calculus in Physics

The derivative is a fundamental tool that quantifies the sensitivity of change for a function’s output with respect to its input. The derivative of a function for a single variable at a chosen input value is the slope of the tangent line to the graph of the function at that point. The application of calculus, including derivative and integral, is widely used in solving problems in the subject of Physics Kinematics. This paper uses derivative to calculate problems involving position, velocity, and acceleration, as well as using integral to solve problems about continuous forces and forces in spring. In calculus, the main idea of derivative is the segmentation process which will be carried on indefinitely and the local range is infinitely smaller. The main idea of integral is the sum of the results of all the infinite differential elements. These ideas can be used to simplify the kinematics question and accurate the final answers.

Protective role of reactive aluminum phases to stabilize soil organic matter against long-term cultivation in the humid tropics under volcanic influence

ABSTRACT Cultivation can cause rapid depletion of soil organic matter (SOM), particularly in the humid tropics. Understanding the factors controlling SOM storage is a key step toward effective soil management for sustainable crop production. While clay + silt content is known to be an important factor for soil organic carbon (SOC) storage, recent studies have shown greater importance of oxalate-extracted Al (Alo; roughly corresponds to short-range-order aluminosilicate minerals and organo-Al complexes) and Fe (Feo). However, the extent to which these mineralogical factors control the response of SOM pool to land-use changes remains unclear, especially in the tropics. This study aimed to clarify the factors regulating SOM content in croplands compared to secondary forests or home gardens in Negros Occidental, Philippines. Along two line transects having a wide range of Alo contents, soil samples were collected at a depth of 0 − 10 cm from sugarcane sites (n = 33; long-term continuous cultivation of >70 years) that were paired with either secondary forests (n = 10) or home gardens (n = 20). Sugarcane sites had significantly lower SOC and total nitrogen (N) contents than secondary forest and home garden sites, whereas there was no clear difference between the latter two land uses. Both SOC and total N contents showed significant positive correlations with Alo content and, to a much less extent, with Feo content, but not with clay + silt content. The slope of the regression line between SOC and Alo was indifferent between sugarcane and the other two land uses, while the intercept was significantly lower in the sugarcane sites. These results suggest the protective role of Alo phases in both agricultural and forest soils and the presence of unprotected SOM (e.g. plant litter) in the latter sites. Furthermore, δ13C analysis suggested that the proportion of forest (C3 plant) derived carbon remaining in the sugarcane soils ranged between 10% and 50% and increased with Alo content. Together, our study showed indirect evidence of Alo-induced stabilization of SOM against long-term cultivation under the humid tropical environment.

Multi-beam Depth Coverage Modeling and Solution Based on Geometric Relationships

In recent years, precise measurements have become increasingly important in various fields. Multibeam bathymetry, known for its wide coverage, high data accuracy, and efficiency, has been widely adopted in scientific research and engineering projects. However, its precision and efficiency are influenced by depth, slope, and survey line direction. Thus, optimizing survey line coverage and overlap is a pressing issue. This study establishes a mathematical model to explore the coverage width and overlap rate of multibeam bathymetry under different depth conditions. Using geometric relationships and trigonometric functions, the model relates measurement range to depth and slope, and its effectiveness is validated with actual survey data. The study proposes optimized survey routes, providing theoretical support and technical guidance for practical measurement work.

Online application of the periodic linear regression method for daily monitoring of photovoltaic systems performance

This paper presents an analysis of the performance of photovoltaic (PV) systems using daily applications of the periodic linear regression method to the performance indicators Final Yield (YF) and Reference Yield (YR). The research was conducted on PV systems installed on rooftops and ground at the Federal Institute of Education, Science, and Technology of Goiás (IFG), Itumbiara Campus, from July 2022 to August 2023. The Energy Monitoring and Management Software (SMGE) was developed to calculate the performance indicators and perform linear regression to analyze the performance of the systems. The results demonstrate that the efficiency of the systems can be monitored by analyzing variations in the slopes of the linear regression lines. An increase in energy conversion efficiency was observed following the cleaning of the PV panels, as reflected in significant changes in the regression slopes. Additionally, natural events, such as rainfall, positively impacted system efficiency. These findings highlight the importance of proper maintenance of PV panels, whether through scheduled cleaning or natural events like rain.

Differing effectiveness of transcranial random noise stimulation and transcranial direct current stimulation for enhancing working memory in healthy individuals: a randomized controlled trial

BackgroundTranscranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (DLPFC) is a promising technique for enhancing working memory (WM) performance in healthy and psychiatric populations. However, limited information is available about the effectiveness of transcranial random noise stimulation (tRNS) applied to the left DLPFC on WM. This study investigated the effectiveness of tRNS on WM compared with that of tDCS, which has established functional evidence.MethodsThis randomized, double-blind, sham-controlled trial enrolled 120 healthy right-handed adults who were randomly allocated to four stimulation groups: tRNS + direct current (DC) offset, tRNS, tDCS, or sham. Each stimulus was placed over the left DLPFC and had a current intensity of 2 mA applied for 20 min during the dual n-back task. The dual n-back task was repeated thrice: pre-stimulation, during stimulation, and post-stimulation. The d-prime scores, and response times were calculated as the main outcome measures. A linear mixed model was created to identify the main effects and interactions between the groups and times, with the group and time as fixed effects, and baseline performance and the subject as a covariate and random effect, respectively. The relationships between the benefit of each stimulus and baseline WM performance were also examined.ResultsFor the d-prime score during stimulation, the tRNS group significantly performed better than the sham group at online assessment (β = 0.310, p = 0.001). In the relationships between the benefit of each stimulus and baseline WM performance, the tRNS group had significantly larger negative line slopes than the sham group for the d-prime score (β = −0.233, p = 0.038).ConclusionstRNS applied to the left DLPFC significantly improved WM performance and generated greater benefits for healthy individuals with lower WM performance. These findings highlight the potential utility of tRNS for enhancing WM performance in individuals with lower WM performance and contribute evidence for clinical application to patients with cognitive decline.Trial RegistrationThis study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000047365) on April 1, 2022; https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000054021.

Proposal of a facet-to-facet multiple flow direction algorithm based on geometrical and mathematical analysis of physical dispersion over triangle facet

Flow direction algorithms have been widely used to extract crucial terrain attributes of great hydrological and geomorphological significance. However, essential distinctions between the empirically-designed strategies of typical algorithms and the natural rules of physical dispersions bring various problems (e.g. parallel channel, artificial dispersion), leading to the low size and extent precisions of estimated results. In this work, geometrical and mathematical analysis is conducted on the inherent characteristics of physical dispersions along slope lines on local terrains. On each 3 × 3 window of digital elevation model (DEM), center pixel is divided into eight non-overlapping sub-facets. Necessary and sufficient (NS) conditions of size relationships between the elevations of adjacent pixels are summarized to directly identify the receiving facets of a sub-facet. Then, strict mathematical relations are derived between slope direction of a sub-facet and flow proportions allocated to receiving facets. A strategy is designed to re-adjust receiving facets and flow proportions for the boundary flow of adjacent facets. Lastly, a multiple-flow-direction algorithm called TFGA is proposed with the NS condition of size relationships, mathematical relation of slope direction with flow proportion, and adjustment strategy of boundary flow. Case studies are conducted for investigating the total contributing areas (TCA) and specific contributing areas (SCA) estimated by TFGA. Results reveal all-side superiorities of TFGA to typical algorithms in spatial patterns, error indicators and statistic characteristics of estimated TCAs and SCAs. Particularly, TFGA improves size precision of estimated results by approximately one order of magnitude. In a conclusion, we highly recommend TFGA for digital elevation analysis.

The relationship of δD and δ18O in soil water and its implications for soil evaporation across distinct rainfall years in winter wheat field in the North China Plain

Soil evaporation plays a key role in regulating local climate and water loss. Stable isotope ratios of water (²H/¹H and ¹⁸O/¹⁶O) are effective tracers for studying water flux. This study examines three isotope-based indicators deuterium excess (d-excess), the slope of the soil water evaporation line (SEL), and line-conditioned excess (lc-excess) across three wheat growing seasons: wet, ordinary, and dry years. The influencing factors of d-excess, SEL, and lc-excess, respectively, soil, vegetation, and meteorology, were analyzed using various methods. Wheat yields varied significantly, reaching 6.69 t ha⁻¹ in wet years, 8.66 t ha⁻¹ in dry years, and 9.28 t ha⁻¹ in ordinary years. The lc-excess was highest in ordinary years, and d-excess peaked during dry years. A negative correlation between d-excess and SEL slope, and between lc-excess and SEL slope, was observed in dry and ordinary years (P<0.05), but not in wet years (P>0.05). Multivariate regression showed that net radiation (Rn) was the primary factor influencing SEL, contributing 54.19 %, 11.58 %, and 29.27 % in wet, dry, and ordinary years, respectively. Leaf area index (LAI) was the most significant factor affecting lc-excess (37.91 % in wet years, 32.22 % in dry, and 30.92 % in ordinary years). Vapor pressure deficit (VPD) affected d-excess in wet and ordinary years, while air (Ta) and soil temperature (Ts) were key in dry years. Variation partitioning revealed meteorological factors primarily influenced SEL, lc-excess, and d-excess in wet years, while soil, vegetation, and climate interactions had greater effects in dry and ordinary years. The lc-excess, integrating multiple factors, is a better indicator of soil evaporation than SEL.

Arterial to jugular-bulb lactate difference in patients undergoing elective brain tumor craniotomy.

Hyperlactatemia is common during tumor craniotomy, but the underlying pathophysiology is unclear. This study measured simultaneous arterial and jugular-bulb lactate concentrations in patients undergoing brain tumor craniotomy to investigate the hypothesis that hyperlactatemia was associated with a net cerebrovascular lactate input. In 20 patients, arterial and jugular-bulb blood was collected hourly from the start of surgery to 6 h postoperatively for measurement of lactate, glucose, and oxygen concentration. For each marker, data were analyzed using a linear mixed-effects model with jugular-bulb concentration as dependent variable, arterial concentration as fixed effect, and patient as random effect. Furthermore, we generated regression lines between arterial and jugular-bulb concentrations. The slope of the regression line between arterial and jugular-bulb lactate was 0.95 (95% CI 0.93-0.97, R2 = 0.98), indicating that increasing arterial lactate levels were associated with an increasingly positive net cerebrovascular balance (net input). The line crossed the identity line at 2.86 (95% CI 0.57-5.16) mmol/L, indicating that lower levels of lactate were associated with a negative net cerebrovascular balance (net output). This suggests a switch from net lactate output during normolactatemia towards net input during hyperlactatemia. Hyperlactatemia in tumor-craniotomy patients probably does not originate from the brain.