Reference Curves Research Articles

Characterization of Dual Spacelike Curves on Dual Lightlike Cone Q~2 Utilizing the Structure Function

This study is about the dual spacelike curves lying on the dual lightlike cone, which can be either symmetric or asymmetric. We first establish the dual associated curve, which is related to the reference curve. Using these curves and the derivative of the reference curve, we derive the dual asymptotic orthonormal frame. Next, we define the dual structure function, curvature function, and Frenet formulae, and express the curvature function in terms of the dual structure function. This leads to a differential equation that characterizes the dual cone curve in relation to its curvature function. Since curves with constant curvature maintain the same curvature at every point, their geometry is more predictable. Therefore, we assume that the dual cone curvature function is constant and examine how this condition affects the behavior and geometric properties of the dual curves. As a result of this investigation, some new results and definitions are obtained.

A Dual-Layer Control System for Steering Stability of Distributed-Drive Electric Vehicle

In addressing the limitations of traditional steering stability control strategies applied to distributed-drive electric vehicles (DDEVs)—which primarily focus on measuring yaw rate and sideslip angle and may result in loss of control during steering maneuvers—this study conducts a more comprehensive analysis of DDEVs’ steering control stability. It specifically investigates the relationships among the lateral positions of both the front and rear wheels, the slip ratios, and the angular orientation of the vehicle’s body during steering processes. Furthermore, a dual-layer steering stability control system aimed at enhancing the steering stability performance of DDEVs is introduced. This control system consists of two components: a lateral controller and a longitudinal controller. The lateral controller aims to establish clear linkages among four key variables, the front and rear wheel sideslip angles, yaw rate, and sideslip angle, and then to compute the necessary active front wheel steering angle and corresponding yaw moment based on the current vehicle body attitude. The findings indicate that, in comparison to the conventional DDEV controller, the proposed two-layer controller achieves substantially closer alignment to the reference curve during steering, with the accuracy increased by a factor of approximately 5 to 20. These results unequivocally affirm the efficacy and viability of the proposed approach.

Synthetic MRI- A new approach of segmentation

Synthetic MRI is a novel technology which aids in the transition from diagnosis based on tissue contrast to intrinsic tissue characteristics. Quantitative information can be helpful in verifying visual assessments of structures and tissues against a normal quantitative standard. With Synthetic MRI, we get new opportunities to monitor and measure disease progression using quantifiable data and to get more information in one third of the time. Synthetic MRI aims at evaluating the value of quantitative MR parameters in the most accurate manner. The ability to quickly quantify the data while also generating several contrast-weighted images will speed up the workflow while at the same time providing clinically relevant data to the patients. With objective measurements and reference curves provided by Synthetic MRI, the diagnostic confidence can be increased.

Artificial intelligence-enabled reconstruction of the right ventricular pressure curve using the peak pressure value: a proof-of-concept study

Abstract Aims Conventional echocardiographic parameters of right ventricular (RV) function are afterload-dependent. Therefore, incorporating RV pressures may enable the formulation of new parameters that reflect intrinsic RV function accurately. Accordingly, we sought to develop an artificial intelligence–based method to reconstruct the RV pressure curve based on the peak RV pressure. Methods and Results We invasively acquired RV pressure in 29 heart failure patients before and after implanting a left ventricular (LV) assist device. Using these tracings, we trained various machine learning models to reconstruct the RV pressure curve of the entire cardiac cycle based on the peak value of the curve. The best-performing model was compared with two other methods that estimated RV pressures based on a reference LV and RV pressure curve, respectively. Seventeen consecutive patients from another centre who underwent right heart catheterization and simultaneous echocardiography served as an external validation cohort. Among the evaluated algorithms, multilayer perceptron (MLP) achieved the best performance with an R2 of 0.887 (0.834–0.941). The RV and LV reference curve–based methods achieved R2 values of 0.879 (0.815–0.943) and 0.636 (0.500–0.771), respectively. During external validation, MLP exhibited similarly good performance [R2 0.911 (0.873–0.948)], which decreased only modestly if the echocardiography-derived peak RV pressure was used instead of the invasively measured peak RV pressure [R2 0.802 (0.694–0.909)]. Conclusions The proposed method enables the reconstruction of the RV pressure curve using only the peak value as input. Thus, it may serve as a fundamental component for developing new echocardiographic tools targeting the afterload-adjusted assessment of RV function.

Reference Ranges and Z-Score Equations for 19 Fetal Cardiac Biometry Structures From 18 to 34 Weeks' Gestation.

To determine equations for calculating the Z-scores of fetal cardiac structures between 18+0 and 34+6 weeks of gestation, create percentile reference tables and curves for the structures, and assess the intra- and inter-observer reproducibility of the measurements. A cross-sectional study was conducted involving 340 normal fetuses from singleton pregnancies between 18 and 34 weeks of gestational age (GA). Nineteen cardiac structures were evaluated: diameters of the mitral, tricuspid, aortic, and pulmonary valve annuli; length, diameter, and area of the left and right ventricles; cardiac area and circumference; and diameters of the ascending aorta, aortic isthmus, main pulmonary artery, right pulmonary artery, left pulmonary artery, and ductus arteriosus. Regression analysis was performed to determine the equations for the mean and standard deviation of all structures using GA, biparietal diameter (BPD), and femur length (FL) as independent variables. All equations had high coefficients of determination (R2). The best performance was achieved using the GA (R2 .819-.944), followed by FL (R2 .813-.937) and BPD (R2 .792-.934). The structure that demonstrated the highest R2 was the cardiac circumference and the smallest was the ductus arteriosus. Reference tables of percentiles 1, 5, 10, 50, 90, 95, and 99, and reference curves of Z-scores were created for all 19 cardiac structures, depending on the GA. All measurements demonstrated good and excellent reproducibility with an inter-observer intraclass correlation coefficient (ICC) of 0.774-0.972 and intra-observer ICC of 0.938-0.993. Equations were produced to calculate Z-scores as well as percentile tables and curves for 19 fetal heart structures. All the measurements demonstrated good reproducibility.

Reference Values for Handgrip Strength, Five Times Sit-to-stand, and Gait Speed in Patients on Hemodialysis.

Low levels of muscle strength and function predict adverse clinical outcomes in patients on hemodialysis; however, reference values remain lacking. We described reference values for handgrip strength, five times sit-to-stand (STS-5), and 4-m gait speed in a large-scale sample in patients on hemodialysis. Baseline data from the SARCopenia trajectories and associations with adverse clinical outcomes in patients on HemoDialysis (SARC-HD) study were analyzed. Muscle strength was evaluated using handgrip strength and the STS-5, whereas physical performance was evaluated using usual 4-m gait speed before a midweek dialysis session. Sex- and age-specific smoothed reference curves for each test at the 3rd, 15th, 50th, 85th, and 97th percentiles were constructed using generalized additive models for location shape and scale. Comparisons between sex and age were also performed. Data from 1004 patients (39% female; 19 to 96 years; 49% ≥ 60 years) were analyzed. Declines in muscle strength and physical performance were observed with advancing age in both sexes. However, among males, muscle strength and performance were similar between 18 and 49 years of age. Males exhibited substantially greater performance in handgrip strength (10.3 kg, 95% confidence interval (CI) 9.1 to 11.4) and 4-m gait speed (-0.10 seconds, 95% CI: -0.14 to -0.05) compared to females. Older patients, independent of sex, exhibited poorer performance on most tests. Lower handgrip strength in the arm with arteriovenous fistula was observed in both sexes (males -2.3 kg, 95% CI: -2.8 to -1.7; and females -2.1 kg, 95% CI: -2.6 to -1.6). Reference values obtained in this study may be used in clinical and research settings to identify patients on hemodialysis with low physical function according to sex and age. Future studies should test these reference values as potential predictors of adverse clinical outcomes.

Study on the effect of mitigation strategies for rail corrugation in metro lines

Rail corrugation appears as a periodic irregularity on the rail running surface that causes severe dynamic loads at the wheel-rail interface. These dynamic forces may generate ground-borne vibrations that propagate from the line to the surrounding buildings causing discomfort to residents. Rail grinding is the most used countermeasure for the mitigation of corrugation. However, this maintenance operation determines high operative costs if frequently performed and must be carefully scheduled. To this end, it is important to assess the effectiveness of other mitigation solutions that may prevent or slow down its growth. The main objective of this study is to investigate the formation of rail corrugation on a sharp curve of the Cityringen underground line in Copenhagen. A wheel-rail interaction model is developed in the frequency domain to identify the root causes of the problem on the specific curve and predict the corrugation wavelength. Once the accuracy of the model is tested against experimental observations on the reference curve, it is used to explore the effectiveness of different mitigation actions, such as the use of friction modifiers, the variation of the speed, track design and track gauge. The results indicate that friction modifiers and speed variation are the most effective measures.

Sediment supply variation control on Lower Eocene delta sequences (Tremp Basin, Spain)

Sediment supply variations are often overlooked when interpreting depositional sequences, with most studies instead emphasizing changes in accommodation space. Here, we investigated a temporally well-constrained shallow-marine succession in the Tremp Basin to test the control of sediment supply variations on the development of deltaic sequences during the early Eocene. We analyzed the paleoenvironmental record (sedimentary facies and δ13Corg values) of the Morillo Limestone and the Castigaleu Formation (52.2−50.6 Ma). The first progradation of the deltaic system is marked by the abrupt appearance of thick delta-front sandstones and associated with the first negative carbon isotopic excursions (CIEs) in the measured δ13Corg record. Subsequent phases of progradation align with subsequent negative CIEs. Conversely, positive CIEs correspond to finer-grained, more-distal prodelta deposits. A series of hyperthermal events occurred during the deposition, globally identified as negative CIEs on δ13Ccarb reference curves, which we tentatively correlate with our δ13Corg data. We therefore suggest that during deposition of this Lower Eocene shallow-marine succession, the primary trigger behind sequence generation was the high-frequency climate-induced variation in sediment supply, specifically the hyperthermal events, rather than changes in accommodation. This linkage underscores the complex interactions between climate dynamics and sedimentary responses that shape the stratigraphic architecture of shallow-marine settings.

Uncertainty quantification analysis of bifurcations of the Allen–Cahn equation with random coefficients

In this work we consider the Allen–Cahn equation, a prototypical model problem in nonlinear dynamics that exhibits bifurcations corresponding to variations of a deterministic bifurcation parameter. Going beyond the state-of-the-art, we introduce a random coefficient in the linear reaction part of the equation, thereby accounting for random, spatially-heterogeneous effects. Importantly, we assume a spatially constant, deterministic mean value of the random coefficient. We show that this mean value is in fact a bifurcation parameter in the Allen–Cahn equation with random coefficients. Moreover, we show that the bifurcation points and bifurcation curves become random objects. We consider two distinct modeling situations: (i) for a spatially-homogeneous coefficient we derive analytical expressions for the distribution of the bifurcation points and show that the bifurcation curves are random shifts of a fixed reference curve; (ii) for a spatially-heterogeneous coefficient we employ a generalized polynomial chaos expansion to approximate the statistical properties of the random bifurcation points and bifurcation curves. We present numerical examples in 1D physical space, where we combine the popular software package Continuation Core and Toolboxes (COCO) for numerical continuation and the Sparse Grids Matlab Kit for the polynomial chaos expansion. Our exposition addresses both dynamical systems and uncertainty quantification, highlighting how analytical and numerical tools from both areas can be combined efficiently for the challenging uncertainty quantification analysis of bifurcations in random differential equations.

Paleomagnetic Secular Variations in North Greenland Around 81°N Over the Last 6,000 Years

AbstractWe investigate full vector paleomagnetic changes recorded in high‐resolution sediments of Petermann Fjord, North Greenland, deposited over the last 6 kyr, in the context of the recent rapid changes in the geomagnetic field. A Paleomagnetic Secular Variation (PSV) stack (inclination, declination, and relative paleointensity) was reconstructed using four marine sediment cores with an independent age model constrained by seven radiocarbon ages. Magnetic investigations demonstrate that the paleomagnetic signal is carried by low coercivity ferrimagnetic minerals and is well reproduced in all cores, attesting to the quality and reliability of the paleomagnetic recording of these sediments. This signal is broadly consistent in directional changes with distant records in North America and the northern North Atlantic at centennial and millennial timescales, and has millennial scale intensity variations that are consistent with model predictions. The offset between a magnetization age determined through comparison with a northern North Atlantic PSV reference curve, GREENICE, and the radiocarbon age model indicates either a reasonable lock‐in depth of magnetization (∼11 cm from the coretop) or centennial‐scale reservoir age variation through time in the fjord. Reconstructed virtual geomagnetic pole (VGP) migration for the last 6 kyr shows that the recent migration of the magnetic North Pole is consistent with secular paleomagnetic variations on geologic timescales. Our results suggest that magnetic field intensity variations (temporal and spatial) are linked to magnetic flux lobe dynamics and influence the VGP migration.

Calculation of continuous reference intervals for biological parameters exhibiting strong age-dependent level changes: Its application to glycosaminoglycans and sialic acid in urine.

Glycosaminoglycan (GAG) and sialic acid (total and free) assays are used as first-line screening tests for the diagnosis of mucopolysaccharidoses and glycoproteinoses, respectively. There is a pronounced age-dependent variation in the urinary concentrations of these metabolites in the normal population, and the stratification of the reference values into discrete age ranges may lead to an undesirably high number of false-positive or false-negative results. The aim of this study was to design a method for calculating continuous reference intervals as a function of age and its application to the analysis of GAGs and sialic acid (total, free, and conjugated) in urine. In the postpubertal period, concentrations of urinary GAGs and sialic acid have reached a plateau, so a traditional calculation of the reference range in this specific age group was considered appropriate. In the prepubertal period, a nonlinear regression performed with the Excel add-in Solver was used to fit the logarithmized concentrations of the controls to a curve that represents the mean values as a function of age. A uniform distribution of the residuals was obtained, which allowed the calculation of the reference intervals by adding the values of their 2.5 and 97.5 percentiles to the independent variable of the regression curve to calculate the upper and lower reference curves. The main advantages of the developed method are (1) a reduction in the number of control samples needed to obtain adequate reference intervals and (2) an improvement in the reliability of diagnostic screening by reducing the uncertainty generated by the gaps in the traditional age-stratified method.

Bone Accrual Trajectories in Children and Adolescents with Perinatal HIV Infection.

Low bone mineral density (BMD) has been reported in children and adolescents living with perinatally-acquired HIV (PHIV). Little is known about their bone accrual through puberty compared to an uninfected healthy cohort. To compare bone accrual in PHIV and healthy children. PHIV children aged 7-16 years had dual energy X-ray absorptiometry (DXA) at entry, 2 years, and then at least 2 years later. Bone accrual was compared to healthy children from the Bone Mineral Density in Childhood Study (BMDCS). United States academic clinical research centers. 172 PHIV; 1321 BMDCS. We calculated height-adjusted whole-body and spine BMD and bone mineral content (BMC) Z-scores in PHIV using BMDCS reference curves. We fit piecewise weighted linear mixed effects models with change points at 11 and 15 years, adjusted for age, sex, race, height Z-score, and Tanner stage, to compare BMD and BMC Z-scores across actual age by cohort.Main Outcome Measure: BMD/BMC Z-scores. Height-adjusted whole-body BMD and BMC Z-scores in PHIV were lower across age compared to BMDCS children. Spine BMD Z-score across age was higher in PHIV after height adjustment. Whole-body and spine bone area tended to be lower in PHIV. PHIV had slower accrual in whole-body and spine bone area before 14 years. After 15 years, bone area accruals were similar, as were height-adjusted spine BMC Z-scores, across age. PHIV had persistent deficits in all measures except height-adjusted spine BMD and BMC Z-scores. Data are needed on PHIV followed to adulthood.

The Small Step Early Intervention Program for Infants at High Risk of Cerebral Palsy: A Single-Subject Research Design Study.

Background/Objectives: Early interventions for infants at high risk of cerebral palsy (CP) are recommended, but limited evidence exists. Our objective was, therefore, to evaluate the effects of the family-centered and interprofessional Small Step early intervention program on motor development in infants at high risk of CP (ClinicalTrials.gov: NCT03264339). Methods: A single-subject research design was employed to investigate participant characteristics (motor dysfunction severity measured using the Hammersmith Infant Neurological Examination (HINE) and Alberta Infant Motor Scale (AIMS) at three months of corrected age (3mCA) related to intervention response. The repeated measures Peabody Developmental Motor Scales-2 fine and gross motor composite (PDMS2-FMC and -GMC) and Hand Assessment for Infants (HAI) were analyzed visually by cumulative line graphs, while the Gross Motor Function Measure-66 (GMFM-66) was plotted against reference percentiles for various Gross Motor Function Classification System (GMFCS) levels. Results: All infants (n = 12) received the Small Step program, and eight completed all five training steps. At two years of corrected age (2yCA), nine children were diagnosed with CP. The children with the lowest HINE < 25 and/or AIMS ≤ 6 at 3mCA (n = 4) showed minor improvements during the program and were classified at GMFCS V 2yCA. Children with HINE = 25-40 (n = 5) improved their fine motor skills during the program, and four children had larger GMFM-66 improvements than expected according to the reference curves but that did not always happen during the mobility training steps. Three children with HINE = 41-50 and AIMS > 7 showed the largest improvements and were not diagnosed with CP 2yCA. Conclusions: Our results indicate that the Small Step program contributed to the children's motor development, with better results for those with an initial higher HINE (>25). The specificity of training could not be confirmed.

The Brain Imaging for Global Health (BRIGHT) Project: Longitudinal cohort study protocol.

There is a scarcity of prospective longitudinal research targeted at early postnatal life which maps developmental pathways of early-stage processing and brain specialisation in the context of early adversity. Follow up from infancy into the one-five year age range is key, as it constitutes a critical gap between infant and early childhood studies. Availability of portable neuroimaging (functional near infrared spectroscopy (fNIRS) and electroencephalography (EEG)) has enabled access to rural settings increasing the diversity of our sampling and broadening developmental research to include previously underrepresented ethnic-racial and geographical groups in low- and middle- income countries (LMICs). The primary objective of the Brain Imaging for Global Health (BRIGHT) project was to establish brain function - using longitudinal data from mother - for-age reference curves infant dyads living in the UK and rural Gambia and investigate the association between context-associated moderators and developmental trajectories across the first two years of life in The Gambia. In total, 265 participating families were seen during pregnancy, at 7-14 days, 1-, 5-, 8-, 12-, 18- and 24-months post-partum. An additional visit is now underway at 3-5 years to assess pre-school outcomes. The majority of our Gambian cohort live in poverty, but while resource-poor in many factors they commonly experience a rich and beneficial family and caregiving context with multigenerational care and a close-knit supportive community. Understanding the impact of different factors at play in such an environment ( i.e., detrimental undernutrition versus beneficial multigenerational family support) will (i) improve the representativeness of models of general cognitive developmental pathways from birth, (ii) identify causal pathways of altered trajectories associated with early adversity at both individual and group level, and (iii) identify the context-associated moderators ( i.e. social context) that protect development despite the presence of poverty-associated challenges. This will in turn contribute to the development of targeted interventions.

Respiratory rates among rural Gambian children: a community-based cohort study

Normal respiratory rates (RR) for children under five in the tropics are well-documented, but data for older children are limited. This study tracked RR changes with age and examined associations with nutritional status and environmental factors. We monitored rural Gambian children aged 6 months to 14 years, recording RR during home visits twice weekly over two rainy seasons. Using a generalized additive model, we constructed RR reference curves, and a linear mixed-effect model identified factors influencing RR. A total of 830 children provided 67,512 RR measurements. Their median age was 6.07 years (interquartile range 4.21–8.55) and 400 (48.2%) were female. Age, stunting, ambient temperature, and time of RR measurement were independent predictors of respiratory rate. Strikingly, children showing signs of illness had greater variability in repeat RR measurements. We constructed a RR reference chart for children aged one to 13 years and proposed a cutoff of > 26 breaths/min for raised RR among children aged > 5 years bridging an important gap in this age group. Although the time of data collection, nutritional status, and ambient temperature were predictors of RR, their effect size is not clinically significant enough to warrant a change in the current WHO guidelines owing to the prevailing uncertainty in the measurement of RR. The finding that RRs between repeat measurements were more variable among children with signs of illness suggests that a single RR measurement may be inadequate to reliably assess the status of sick children—a population in which accurate diagnosis is essential to enable targeted interventions with lifesaving treatment.

Effect of Time and Sex on Post-Anterior Cruciate Ligament Reconstruction Psychological Patient-Reported Outcome Measure Scores.

Low scores on psychological patient-reported outcomes measures, including the Anterior Cruciate Ligament-Return to Sport After Injury (ACL-RSI) and Injury-Psychological Readiness to Return to Sport (I-PRRS), after anterior cruciate ligament reconstruction (ACLR) have been associated with a maladaptive psychological response to injury and poor prognosis. To assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores and generate normative reference curves. Case series. Outpatient sports medicine and orthopaedic clinic. A total of 507 patients (age at ACLR, 17.9 ± 3.0 years) who had undergone primary ACLR and completed ACL-RSI or I-PRRS assessments ≥1 times (n = 796) between 0 and 1 year post-ACLR. An honest broker provided anonymous data from our institution's knee-injury clinical database. Generalized additive models for location, scale, and shape and generalized least-squares analyses were used to assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores. The ACL-RSI and I-PRRS scores increased over time post-ACLR. Males had higher scores than females until approximately 5 months post-ACLR, with scores converging thereafter. Males reported higher ACL-RSI and I-PRRS scores than females in the initial stages of rehabilitation, but scores converged between sexes at times associated with return to play post-ACLR. Normative reference curves can be used to objectively appraise ACL-RSI and I-PRRS scores at any time post-ACLR. This may lead to timely recognition of patients with a maladaptive psychological response to injury and a higher likelihood of a poor prognosis, optimizing ACLR outcomes.

Establishment and Verification of a Risk Prediction Model for Chronic Rhinosinusitis.

Objective: Factors influencing chronic rhinosinusitis (CRS) are usually studied in terms of genetics and environment; however, clinical indicators have not been reported. This case-control study was conducted in Ningbo, China, to explore new independent risk factors for CRS. Methods: A total of 695 participants, including 440 healthy controls and 255 patients with CRS, were included in this study. Clinical data were retrieved from questionnaires and electronic medical record systems of hospitals. Independent risk factors were screened using logistic regression and 10-fold cross-validation combined with the least absolute shrinkage and selection operator. A CRS risk prediction model was established using logistic regression, and nomograms were visualized. The model was validated and evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). Results: Ten independent risk factors, including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatinine, triglyceride, total cholesterol, red blood cell count, hemoglobin, lymphocyte percentage, and monocyte percentage were screened. ROC analysis showed that the area under the curve of the training set was 0.890, indicating that the predictive model had excellent discriminant ability. The calibration curves showed that the fitting curves of the training set were close to the reference curves, indicating that the model had a good fit. The DCA showed that the threshold probability range of the training set was 1% to 89%. Conclusions: Independent risk factors for CRS were screened, and a prediction model was constructed, which is of significance for the prevention, control, and treatment of the disease.

A mid-Cretaceous carbon isotope reference curve for the SE Neo-Tethys region (Zagros, W Iran)

Stable carbon isotope chemostratigraphy and the associated reference curves have proved to be valuable tools for stratigraphic calibration and long-distance correlations. Nonetheless, the reference curves covering the Cretaceous have mostly been produced from localities located within the W Neo-Tethys. In order to establish a reference curve for the SE Neo-Tethys margin, an Aptian–Albian hemipelagic carbonate-rich succession deposited along the Zagros Basin (SW Iran) was examined for planktic foraminifera biostratigraphy, carbon isotope stratigraphy, and sedimentological characteristics. Eight biozones including Globigerinelloides ferreolensis, Globigerinelloides algerianus, Hedbergella trocoidea, Paraticinella bejaouaensis, Muricohedbergella planispira, Ticinella (T.) primula, Biticinella breggiensis, and Pseudothalmanninella (P.)ticinensis as well as two subzones enclosing T. praeticinensis and P. subticinensis assign the strata to the early late Aptian–late Albian age. A carbon isotope record constrained by the planktic foraminifera zonation scheme shows good concordance with existing composite reference curves from the W Neo-Tethys region. Several carbon isotope excursions (CIEs) characterizing global marine events including Oceanic Anoxic Event (OAE) 1a, OAE1b, OAE1c and associated sub-events can be identified in the studied section. Deoxygenated bottom waters associated with the formation of OAE1a and OAE1b are indicated by distinct lithological signatures including enrichment in pyrite and glauconite, nodular and stratiform chert beds, as well as enhanced organic matter contents. We integrate the here-studied interval with a previously published upper Albian−Turonian succession from the same outcrop section, forming a composite, stratigraphically well-constrained section. This results in a high-resolution carbon isotope record for the SE Neo-Tethys margin, considered to represent an expedient reference Aptian–Turonian curve for this region. Correlation of this new curve with previously published records from the Middle East has helped to address ambiguities regarding the stratigraphic positions of the early/late Aptian and Aptian/Albian boundaries identified by previous studies.

Capillary blood parameters are gestational age, birthweight, delivery mode and gender dependent in healthy preterm and term infants.

The measurement of blood pH and gas analytes (BPGA), soon after birth, constitutes the first-line standard of care procedure in high-risk newborns. However, no data is available in capillary blood on perinatal bias such as gestational age (GA), weight at birth (BW), delivery mode, and gender. The aims of the present study were to investigate whether in a cohort of healthy preterm (PT) and term (T)infants BPGA were GA, BW, delivery mode and gender dependent, thus affecting BPGA reliability as diagnostic test. We performed a prospective case-control study in 560 healthy infants (PT: n=115, T: n=445). BPGA was measured within 24-h from birth. Perinatal characteristics, outcomes, and clinical examination were also recorded. PT infants showed higher (p<0.001) carbon dioxide partial pressure (pCO2), fraction of fetal hemoglobin (HbF), base excess (BE), bicarbonate (HCO3), and lower lactate (Lac) levels. When corrected for delivery mode, higher (p<0.001) HbF, BE, HCO3, and lower Lac levels were found. Similarly, higher (p<0.05, for all) pCO2, HbF, BE, HCO3 and lower Lac levels were found between female and male PT and T infants. Repeated multiple logistic regression analysis showed that BPGA was GA, BW, delivery mode and gender dependent. The present results showing that BPGA can be affected by a series of perinatal outcomes open the way to further investigations providing longitudinal BPGA reference curves in the transitional phase, thus empowering BPGA role as a reliable diagnostic and therapeutic strategies efficacy marker.

The reference curves of percentile for the length and head circumference of infants aged 0–1 year in Hainan Province, China

We first established percentile reference curves for infant length and head circumference in Hainan Province based on gender and age in months and compared them with the 2022 national standards and World Health Organization (WHO) standards. This cross-sectional survey involved 2736 infants (1471 boys and 1265 girls) in 18 cities and counties in Hainan Province. Standardized instruments were used to measure head circumference and length. Reference values for Hainan infants' length and head circumference were determined using the LMS method. Curves were generated using the LMS Chart Maker software. According to the newly established reference curves, the length and head circumference of Hainan infants exhibited a consistent trend of steady growth. However, the average head circumference was below the 2022 national reference values and WHO standards. The mean length was lower than the new national reference values but roughly consistent with the WHO standards. Differences exist in infant length and head circumference in Hainan compared to national and global averages. To enhance infant length and head circumference growth, the health department should encourage exclusive breastfeeding for the first 6 months, ensure infants' sleep needs at night, and promote the regularity of vitamin D supplementation during the perinatal period.