New discretization and solution techniques for incompressible viscous flow problems

Several topics arising in the finite element solution of the incompressible Navier-Stokes equations are considered. Specifically, the question of choosing finite element velocity/pressure spaces is addressed, particularly from the viewpoint of achieving stable discretizations leading to convergent pressure approximations. The role of artificial viscosity in viscous flow calculations is studied, emphasizing work by several researchers for the anisotropic case. The last section treats the problem of solving the nonlinear systems of equations which arise from the discretization. Time marching methods and classical iterative techniques, as well as some modifications are mentioned

Prediction of small-for-gestational-age neonates at 35-37 weeks' gestation: contribution of maternal factors and growth velocity between 20 and 36 weeks

Objective: To evaluate the performance of ultrasonographic estimated fetal weight (EFW) at 35+0 - 36+6 weeks’ gestation in the prediction of small for gestational age (SGA) neonates and assess the additive value of first, maternal risk factors and second, fetal growth velocity between 20 and 36 weeks’ gestation in improving such prediction. Methods: This was a prospective study of 44,043 singleton pregnancies that had undergone routine ultrasound examination at 19+0 - 23+6 and at 35+0 - 36+6 weeks’ gestation. Multivariable logistic regression analysis was used to determine whether addition of maternal risk factors and growth velocity, defined by a difference in EFW Z-scores or fetal abdominal circumference (AC) Z-scores between the third and second trimester scans divided by the time interval between them, improved the performance of EFW at 35+0 - 36+6 weeks in the prediction of delivery of SGA neonates with birthweight <10th and <3rd percentiles within two weeks and at any stage after assessment. Results: Screening by EFW at 35+0 - 36+6 weeks’ gestation <10th percentile predicted 63.4% (95% CI 62.0, 64.7) of neonates with birthweight <10th percentile and 74.2% (95% CI 72.2, 76.1) of neonates with birthweight <3rd percentile born at any stage after assessment, at screen positive rate of 10%. The respective values for SGA neonates born within two weeks of assessment were 76.8% (95% CI 74.4, 79.0) and 81.3% (95% CI 78.2, 84.0). In the group of fetuses with EFW <10th percentile, 43.7% were born with birthweight ≥10th percentile. For a desired 90% detection rate of SGA neonates delivering at any stage after assessment the necessary screen positive rate would be 33.7% for SGA <10th percentile and 24.4% for SGA <3rd percentile. Multivariable logistic regression analysis demonstrated that in the prediction of SGA neonates with birthweight <10th and <3rd percentiles there was a significant contribution from EFW Z-score at 35+0 - 36+6 weeks’ gestation, maternal risk factors and AC growth velocity, but not EFW growth velocity. However, the area under the receiver operating characteristic curves for SGA neonates in screening by maternal risk factors and EFW Z-score was not improved by addition of AC growth velocity. Conclusion: Screening for SGA neonates by EFW at 35+0 - 36+6 weeks’ gestation and use of a cut-off of the 10th percentile predicts 63% of affected neonates. Prediction of 90% of SGA neonates necessitates classification of about 35% of the population as being screen positive use of the 35th percentile cut-off in EFW. The predictive performance of EFW is not improved by addition of estimated growth velocity between the second and third trimesters of pregnancy

Synoptic and dynamic characteristics of selected deep depressions over Cyprus

International audienceIn this study, the spatial and temporal distributions of dynamic and synoptic characteristics of a selection of 32 deep baroclinic depressions have been investigated. The study covers the cold period months of November till March, in the period from 1 November 1986 to 31 March 2003. For the needs of the study, several synoptic characteristics of these depressions have been extracted. Also, several dynamic characteristics during the evolution of the depressions were studied: relative vorticity, divergence, vertical motion and a static stability parameter. The results are presented in the form of isobaric distributions over, three tropospheric isobaric levels, namely the lower 850 hPa, the middle 500 hPa and the upper 300 hPa

Prediction of small-for-gestational-age neonates at 35-37 weeks' gestation: contribution of maternal factors and growth velocity between 32 and 36 weeks

Objective: To assess the additive value of fetal growth velocity between 32 and 36 weeks’ gestation on the performance of ultrasonographic estimated fetal weight (EFW) at 35+0 - 36+6 weeks’ gestation for prediction of small for gestational age (SGA) neonates and adverse perinatal outcome. Methods: This was a prospective study of 14,497 singleton pregnancies that had undergone routine ultrasound examination at 28+0 - 34+6 and at 35+0 - 36+6 weeks’ gestation. Multivariable logistic regression analysis was used to determine whether addition of growth velocity, defined by a difference in EFW and abdominal circumference (AC) Z-scores between the early and late third trimester scans divided by the time interval between them, improved the performance of EFW at 35+0 - 36+6 weeks in the prediction of first, delivery of SGA neonates with birthweight <10th and <3rd percentiles within two weeks and at any stage after assessment and second, composite of adverse perinatal outcome defined as stillbirth, neonatal death or admission to the neonatal unit for ≥48 hours. Results Multivariable logistic regression analysis demonstrated that significant contributors to prediction of SGA neonates were EFW Z-score at 35+0 - 36+6 weeks’ gestation, fetal growth velocity by either AC or EFW Z-scores and maternal risk factors. The area under the receiver operating characteristic curves (AUROC) and detection rate (DR) with 95% confidence interval, at 10% screen positive rate, for prediction of SGA neonates <10th percentile born within two weeks of assessment achieved by EFW Z-score at 35+0 - 36+6 weeks (AUROC 0.938, 0.928 - 0.947; DR 80.7, 77.6 - 83.9) were not significantly improved by addition of EFW growth velocity and maternal risk factors (AUROC 0.941, 0.932 - 0.950; p=0.061; DR 82.5, 79.4 - 85.3). Similar results were obtained when growth velocity was defined by AC rather than EFW growth velocity. Similarly, there was no significant improvement in AUROC and DR, at 10% screen positive rate, for prediction of SGA neonates <10th percentile born at any stage after assessment or SGA neonates <3rd percentile born within two weeks or at any stage after assessment achieved by EFW Z-score at 35+0 - 36+6 weeks by addition of maternal factors and either EFW growth velocity of AC growth velocity. Multivariable logistic regression analysis demonstrated that the only significant contributor to adverse perinatal outcome was maternal risk factors. Multivariable logistic regression analysis in the group with EFW <10th percentile demonstrated that significant contribution to prediction of birth of neonates with birthweight <10th and <3rd percentiles and adverse perinatal outcome was provided by EFW Z-score at 35+0 - 36+6 weeks, but not by AC growth velocity <1st decile. Conclusion: The predictive performance of EFW at 35+0 - 36+6 weeks’ gestation for birth of SGA neonates and adverse perinatal outcome is not improved by addition of estimated growth velocity between 32 and 36 weeks’ gestation

Prediction of adverse perinatal outcome by cerebroplacental ratio in women undergoing induction of labor

Objective: To investigate the performance of screening for adverse perinatal outcome by the cerebroplacental ratio (CPR) measured within 24 hours of induction of labor. Methods: This was a prospective observational study in 1,902 singleton pregnancies undergoing induction of labor at ≥ 37 weeks’ gestation. Doppler ultrasound was used to measure the pulsatility index (PI) in the umbilical artery (UA) and fetal middle cerebral artery (MCA) before induction of labor. The measured UA PI and MCA PI and their ratio were converted to multiples of the median (MoM) after adjustment for gestational age. Univariate and multivariate logistic regression analysis was used to determine whether CPR improved the prediction of adverse perinatal outcome that was provided by maternal characteristics, medical history and obstetric factors. The detection rate (DR) and false-positive rate (FPR) of screening by CPR were estimated for cesarean section for presumed fetal distress and neonatal adverse outcome, which included umbilical arterial or venous cord blood pH ≤7 and ≤7.1, respectively, 5-minute Apgar score 24 hours, or hypoxic ischemic encephalopathy. Results: A combination of maternal and pregnancy characteristics, including age, weight, racial origin, previous obstetric history, preeclampsia, gestational age at delivery and amniotic fluid volume, identified 39% of pregnancies requiring cesarean section for fetal distress at FPR of 10%; addition of CPR did not improve the performance of screening. In screening for adverse neonatal outcome by a combination of parity and CPR the DR was 17% at FPR of 10%. Conclusion: Low CPR, measured within 24 hours of induction of labor, is associated with increased risk of cesarean section for fetal distress and adverse neonatal outcome, but the performance of CPR for such surrogates of adverse perinatal outcome is poor

Intelligent Noninvasive Diagnosis of Aneuploidy:Raw Values and Highly Imbalanced Dataset

The objective of this paper is to introduce a noninvasive diagnosis procedure for aneuploidy and to minimize the social and financial cost of prenatal diagnosis tests that are performed for fetal aneuploidies in an early stage of pregnancy. We propose a method by using artificial neural networks trained with data from singleton pregnancy cases, while undergoing first trimester screening. Three different datasets' with a total of 122 362 euploid and 967 aneuploid cases were used in this study. The data for each case contained markers collected from the mother and the fetus. This study, unlike previous studies published by the authors for a similar problem differs in three basic principles: 1) the training of the artificial neural networks is done by using the markers' values in their raw form (unprocessed), 2) a balanced training dataset is created and used by selecting only a representative number of euploids for the training phase, and 3) emphasis is given to the financials and suggest hierarchy and necessity of the available tests. The proposed artificial neural networks models were optimized in the sense of reaching a minimum false positive rate and at the same time securing a 100% detection rate for Trisomy 21. These systems correctly identify other aneuploidies (Trisomies 13&18, Turner, and Triploid syndromes) at a detection rate greater than 80%. In conclusion, we demonstrate that artificial neural network systems can contribute in providing noninvasive, effective early screening for fetal aneuploidies with results that compare favorably to other existing methods

Value of routine ultrasound examination at 35–37 weeks' gestation in diagnosis of non‐cephalic presentation

Background: Undiagnosed non-cephalic presentation in labor carries increased risks for both the mother and baby. Routine pregnancy care based on maternal abdominal palpation fails to detect the majority of non-cephalic presentations. Objective: To report the incidence of non-cephalic presentation at a routine scan at 35+0 - 36+6 weeks’ gestation and subsequent management of such pregnancies. Methods: This was a retrospective analysis of prospectively collected data in 45,847 singleton pregnancies that had undergone routine ultrasound examination at 35+0 - 36+6 weeks’ gestation. Patients with breech or transverse / oblique presentation were divided into two groups, first those that would have elective cesarean section for fetal or maternal indications other than the abnormal presentation, and second, those that would potentially require ECV. The latter group was reassessed in 1-2 weeks and if there was persistence of the abnormal presentation the parents were offered the options of ECV versus elective cesarean section at 38-40 weeks’ gestation. Multivariable logistic regression analysis was carried out to determine which of the factors from maternal and pregnancy characteristics provided a significant contribution in the prediction of first, non-cephalic presentation at the 35+0 - 36+6 weeks scan, second, successful ECV from non-cephalic to cephalic presentation, and third, spontaneous rotation from non-cephalic to cephalic presentation. Results: First, at 35+0 - 36+6 weeks the fetal presentation was cephalic in 43,416 (94.7%) pregnancies, breech in 1,987 (4.3%) and transverse or oblique in 444 (1.0%). Second, multivariable analysis demonstrated that the chance of non-cephalic presentation increased with increasing maternal age and weight, decreasing height, earlier gestational age at scan, and it was higher in the presence of placenta previa, oligohydramnios and polyhydramnios, in nulliparous than parous women and lower in women of South Asian and mixed racial origin than in White women. Third, 22% of cases of non-cephalic presentation were not eligible for ECV because of planned cesarean section for indications other than the malpresentation. Fourth, of those eligible for ECV only 48.5% (646/1,332) accepted the procedure and this was successful in 39.0% (252/646) of cases. Fifth, the chance of successful ECV increased with increasing maternal age and was lower in nulliparous than parous women. Sixth, in 33.9% (738/2,179) of pregnancies with non-cephalic presentation where successful ECV was not carried out there was a subsequent spontaneous rotation to cephalic presentation. Seventh, the chance of spontaneous rotation from non-cephalic to cephalic presentation increased with increasing interval between the scan and delivery and decreased with increasing birth weight, it was higher in women of Black than White racial origin, if the presentation was transverse or oblique than breech and if there was polyhydramnios and lower in nulliparous than parous women and in the presence of placenta previa. Eighth, in 109 (0.3%) of cephalic presentations there was subsequent rotation to non-cephalic presentation and in 41% of these the diagnosis was made during labor. Ninth, in the total of 2,431 cases of non-cephalic presentation at the time of the scan the presentation at birth was cephalic in 985 (40.5%); in 738 (74.9%) this was due to spontaneous rotation and in 247 (25.1%) due to successful ECV. Tenth, prediction of non-cephalic presentation at the 35+0 - 36+6 weeks scan and successful ECV from maternal and pregnancy factors was poor, but prediction of spontaneous rotation from non-cephalic to cephalic presentation was moderately good and this could be incorporated in the counselling of women prior to undertaking ECV. Conclusions: The problem of unexpected non-cephalic presentation in labor can to a great extent be overcome by a routine ultrasound examination at 35+0 - 36+6 weeks’ gestation. The incidence of non-cephalic presentation at the 35+0 - 36+6 weeks scan was about 5%, but, in about 40% of these cases the presentation at birth was cephalic, mainly due to subsequent spontaneous rotation and to a lesser extent as a consequence of successful ECV

Lipid Composition of Comedones Compared With That of Human Skin Surface in Acne Patients

TLC† analysis of comedo lipids from the face, neck, chest and back of acne patients of both sexes, ages 12 to 26 years, (some 65 specimens) gave the same gross composition except for hydrocarbons more saturated than squalene and lipids more polar than free cholesterol. Quantitative data (chromatography plus GLC of isolated fractions) on both comedo and surface lipids from each of 3 acne patients revealed the following. Free fatty acids plus triglycerides comprised ∼63% of both comedo and skin surface lipids. However, for the comedo, 90% of this sum was free fatty acids compared with only 25% for surface lipid. This implies that triglycerides in comedo lipids are nearly completely hydrolyzed but only 25% hydrolyzed in surface lipids. GLC patterns of the free fatty acids were almost identical for both surface and comedo lipids in all 3 subjects except for slightly more unsaturated acids in surface lipids. For comedo and surface lipids respectively, wax esters were 14% and 24%, sterol esters 4% and 2%, free cholesterol 12% and 2%, and squalene 8% and 9%. Absence of free alcohols and constancy of GLC composition of the entire wax ester fraction indicated it was not hydrolyzed in either surface or comedo lipids. GLC composition of the entire sterol ester fraction from comedones indicated that the fatty acids were derived from epidermis and sebum

IONA test for first-trimester detection of trisomies 21, 18 and 13

OBJECTIVE: To assess the potential performance of screening for fetal trisomies 21, 18 and 13 by cell-free DNA (cfDNA) analysis of maternal blood using the IONA\uae test. METHODS: This was a nested case-control study of cfDNA analysis of maternal plasma using the IONA test. Samples were obtained at 11-13 weeks' gestation, before chorionic villus sampling, from 201 euploid pregnancies, 35 with trisomy 21, four with trisomy 18 and two with trisomy 13. Laboratory personnel were blinded to the fetal karyotype. RESULTS: Probability scores for trisomies 21, 18 and 13 were given for 241/242 samples analyzed. No probability score was provided for one (0.5%) euploid pregnancy because of low fetal fraction. In all 35 cases of trisomy 21 the probability score for trisomy 21 was > 95% and the scores for trisomies 18 and 13 were 64 0.0001%. In all four cases of trisomy 18, the probability score for trisomy 18 was > 77% and the scores for trisomies 21 and 13 were 64 0.0001%. In the two cases of trisomy 13, the probability score for trisomy 13 was > 59% and the scores for trisomies 21 and 18 were 64 0.0001%. In the 200 euploid pregnancies with a test result, the probability score was < 0.08% for trisomy 21, < 0.001% for trisomy 18 and < 0.002% for trisomy 13. Therefore, the IONA test detected 100% of all three trisomies, with a false-positive rate of 0%. CONCLUSION: The IONA test successfully differentiated all cases of trisomies 21, 18 and 13 from euploid pregnancies

Ultrasound IMT measurement on a multi-ethnic and multi-institutional database: Our review and experience using four fully automated and one semi-automated methods

Automated and high performance carotid intima-media thickness (IMT) measurement is gaining increasing importance in clinical practice to assess the cardiovascular risk of patients. In this paper, we compare four fully automated IMT measurement techniques (CALEX, CAMES, CARES and CAUDLES) and one semi-automated technique (FOAM). We present our experience using these algorithms, whose lumen-intima and media-adventitia border estimation use different methods that can be: (a) edge-based; (b) training-based; (c) feature-based; or (d) directional Edge-Flow based. Our database (DB) consisted of 665 images that represented a multi-ethnic group and was acquired using four OEM scanners. The performance evaluation protocol adopted error measures, reproducibility measures, and Figure of Merit (FoM). FOAM showed the best performance, with an IMT bias equal to 0.025 ± 0.225 mm, and a FoM equal to 96.6%. Among the four automated methods, CARES showed the best results with a bias of 0.032 ± 0.279 mm, and a FoM to 95.6%, which was statistically comparable to that of FOAM performance in terms of accuracy and reproducibility. This is the first time that completely automated and user-driven techniques have been compared on a multi-ethnic dataset, acquired using multiple original equipment manufacturer (OEM) machines with different gain settings, representing normal and pathologic case