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 large-for-gestational-age neonate by routine third-trimester ultrasound

Objectives: First, to evaluate and compare the performance of routine ultrasonographic estimated fetal weight (EFW) and fetal abdominal circumference (AC) at 31+0 - 33+6 and 35+0 - 36+6 weeks’ gestation in the prediction of large for gestational age (LGA) neonates born at ≥37 weeks’ gestation. Second, to assess the additive value of fetal growth velocity between 32 and 36 weeks’ gestation on the performance of EFW at 35+0 - 36+6 weeks’ gestation for prediction of LGA neonates. Third, to define the predictive performance for LGA neonates of different EFW cut-offs at routine ultrasound examination at 35+0 - 36+6 weeks’ gestation. Fourth, to propose a two-stage strategy for identifying pregnancies with LGA fetuses that may benefit from iatrogenic delivery during the 38th gestational week. Methods: First, data from 21,989 singleton pregnancies that had undergone routine ultrasound examination at 31+0 - 33+6 weeks’ gestation and 45,847 that had undergone routine ultrasound examination at 35+0 - 36+6 weeks were used to compare the predictive performance of EFW and AC for LGA neonates with birthweight >90th and >97th percentiles born at ≥37 weeks’ gestation. Second, data from 14,497 singleton pregnancies that had undergone routine ultrasound examination at 35+0 - 36+6 weeks’ gestation and had a previous scan at 30+0 – 34+6 weeks were used to determine, through multivariable logistic regression analysis, whether addition of growth velocity, defined by a difference in EFW and 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 delivery of LGA neonates born at ≥37 weeks’ gestation. Third, in the database of the 45,847 pregnancies that had undergone routine ultrasound examination at 35+0 - 36+6 weeks’ gestation the screen positive and detection rate of LGA neonates born at ≥37 weeks’ gestation and at ≤10 days from the initial scan were calculated for different EFW percentile cut-offs between the 50th and 90th percentile. Results: First, the areas under the receiver operating characteristic curves (AUROC) of screening for LGA neonates were significantly higher with EFW Z-score than AC Z-score and at 35+0 - 36+6 than at 31+0 - 33+6 weeks’ gestation (p90th percentile at 35+0 - 36+6 weeks’ gestation the predictive performance for LGA neonates born at ≥37 weeks’ gestation was modest (65% and 46% for neonates with birthweight >97th and >90th percentiles, respectively, at screen positive rate of 10%), but the performance was better for prediction of LGA neonates born at ≤10 days from the scan (84% and 71% for neonates with birthweight >97th and >90th percentiles, respectively, at screen positive rate of 11%). Fourth, screening by EFW >70th percentile at 35+0 - 36+6 weeks’ gestation predicted 91% and 82% of LGA neonates with birthweight >97th and >90th percentiles born at ≥37 weeks’ gestation, at screen positive rate of 32%, and the respective values of screening by EFW >85th percentile for prediction of LGA neonates born at ≤10 days from the scan were 88%, 81% and 15%. On the basis of these results it was proposed that routine fetal biometry at 36 weeks’ gestation is a screening rather than diagnostic test for fetal macrosomia and that EFW >70th percentile should be used to identify pregnancies in need for another scan at 38 weeks and in the latter those with EFW >85th percentile should be considered for iatrogenic delivery during the 38th week. Conclusions: First, the predictive performance for LGA neonates by routine ultrasonographic examination during the third trimester is higher if the scan is carried out at 36 than at 32 weeks, the method of screening is EFW than fetal AC, the outcome measure is birthweight >97th than >90th percentile and if delivery occurs within 10 days than at any stage after assessment. Second, prediction of LGA neonates by EFW >90th percentile is modest and the study presents a two-stage strategy for maximizing the prenatal prediction of LGA neonates

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

Fetal major cardiac defects and placental dysfunction at 11-13 weeks' gestation

Objectives: To investigate the relationship between fetal major cardiac defects and markers of placental perfusion and function. Methods: This was a prospective screening study in singleton pregnancies at 11-13 weeks’ gestation. Uterine artery pulsatility index (UTPI), serum pregnancy associated plasma protein-A (PAPP-A) and placental growth factor (PLGF) were measured and the values were converted into multiples of the normal median (MoM). Median MoM values in fetuses with isolated major cardiac defects were compared to those in fetuses without major defects. Results: The 50,094 singleton pregnancies fulfilling the entry criteria included 49,898 pregnancies with a normal cardiac anatomy and 196 (0.39%) with major congenital cardiac defects; 73 (37.2%) with conotruncal defects, 63 (32.1%) with left ventricular outflow tract (LVOT) defects and 60 (30.6%) with valvular defects. In the group of cardiac defects, compared to controls, there was lower median PAPP-A MoM (0.81 vs 1.00, p<0.0001) and PLGF MoM (0.78 vs 1.00, p<0.0001) but no significant difference in UTPI MoM (1.01 vs 1.00, p=0.162). Conclusions: In pregnancies with isolated major cardiac defects there is evidence of placental dysfunction in the absence of impaired placental perfusion

Transoral laser surgery for laryngeal carcinoma: has Steiner achieved a genuine paradigm shift in oncological surgery?

Transoral laser microsurgery applies to the piecemeal removal of malignant tumours of the upper aerodigestive tract using the CO2 laser under the operating microscope. This method of surgery is being increasingly popularised as a single modality treatment of choice in early laryngeal cancers (T1 and T2) and occasionally in the more advanced forms of the disease (T3 and T4), predomi- nantly within the supraglottis. Thomas Kuhn, the American physicist turned philosopher and historian of science, coined the phrase ‘paradigm shift’ in his groundbreaking book The Structure of Scientific Revolutions. He argued that the arrival of the new and often incompatible idea forms the core of a new paradigm, the birth of an entirely new way of thinking. This article discusses whether Steiner and col- leagues truly brought about a paradigm shift in oncological surgery. By rejecting the principle of en block resection and by replacing it with the belief that not only is it oncologically safe to cut through the substance of the tumour but in doing so one can actually achieve better results, Steiner was able to truly revolutionise the man- agement of laryngeal cancer. Even though within this article the repercussions of his insight are limited to the upper aerodigestive tract oncological surgery, his willingness to question other peoples’ dogma makes his contribution truly a genuine paradigm shift

Severity of asymptomatic carotid stenosis and risk of ipsilateral hemispheric ischaemic events: Results from the ACSRS study

Objectives. This study determines the risk of ipsilateral ischaemic neurological events in relation to the degree of asymptomatic carotid stenosis and other risk factors. Methods. Patients (n = 1115) with asymptomatic internal carotid artery (ICA) stenosis greater than 50% in relation to the bulb diameter were followed up for a period of 6-84 (mean 37.1) months. Stenosis was graded using duplex, and clinical and biochemical risk factors were recorded. Results. The relationship between ICA stenosis and event rate is linear when stenosis is expressed by the ECST method, but S-shaped if expressed by the NASCET method. In addition to the ECST grade of stenosis (RR 1.6; 95% CI 1.21-2.15), history of contralateral TIAs (RR 3.0; 95% CI 1.90-4.73) and creatinine in excess of 85 μmol/L (RR 2.1; 95% CI 1.23-3.65) were independent risk predictors. The combination of these three risk factors can identify a high-risk group (7.3% annual event rate and 4.3% annual stroke rate) and a low risk group (2.3% annual event rate and 0.7% annual stroke rate). Conclusions. Linearity between ECST percent stenosis and risk makes this method for grading stenosis more amenable to risk prediction without any transformation not only in clinical practice but also when multivariable analysis is to be used. Identification of additional risk factors provides a new approach to risk stratification and should help refine the indications for carotid endarterectomy. © 2005 Elsevier Ltd. All rights reserved

The various power decays of the survival probability at long times for free quantum particle

The long time behaviour of the survival probability of initial state and its dependence on the initial states are considered, for the one dimensional free quantum particle. We derive the asymptotic expansion of the time evolution operator at long times, in terms of the integral operators. This enables us to obtain the asymptotic formula for the survival probability of the initial state $\psi (x)$, which is assumed to decrease sufficiently rapidly at large $|x|$. We then show that the behaviour of the survival probability at long times is determined by that of the initial state $\psi$ at zero momentum $k=0$. Indeed, it is proved that the survival probability can exhibit the various power-decays like $t^{-2m-1}$ for an arbitrary non-negative integers $m$ as $t \to \infty$, corresponding to the initial states with the condition $\hat{\psi} (k) = O(k^m)$ as $k\to 0$.Comment: 15 pages, to appear in J. Phys.

What went wrong? The flawed concept of cerebrospinal venous insufficiency

In 2006, Zamboni reintroduced the concept that chronic impaired venous outflow of the central nervous system is associated with multiple sclerosis (MS), coining the term of chronic cerebrospinal venous insufficiency ('CCSVI'). The diagnosis of 'CCSVI' is based on sonographic criteria, which he found exclusively fulfilled in MS. The concept proposes that chronic venous outflow failure is associated with venous reflux and congestion and leads to iron deposition, thereby inducing neuroinflammation and degeneration. The revival of this concept has generated major interest in media and patient groups, mainly driven by the hope that endovascular treatment of 'CCSVI' could alleviate MS. Many investigators tried to replicate Zamboni's results with duplex sonography, magnetic resonance imaging, and catheter angiography. The data obtained here do generally not support the 'CCSVI' concept. Moreover, there are no methodologically adequate studies to prove or disprove beneficial effects of endovascular treatment in MS. This review not only gives a comprehensive overview of the methodological flaws and pathophysiologic implausibility of the 'CCSVI' concept, but also summarizes the multimodality diagnostic validation studies and open-label trials of endovascular treatment. In our view, there is currently no basis to diagnose or treat 'CCSVI' in the care of MS patients, outside of the setting of scientific research

Who are we becoming? A critical, communicative, reflective, transformative, timely inquiry into the coming-to-be of adult education in the early 21st century

The perspectives included in this collaborative document reflect the authors‘ initial inquiry to explore who are we becoming as adult educators. We present five unique points of view that our role as adult educators holds potential to help adults seek ways into their own deep inquiries of what are true, beautiful, and just ways of life. Our inquiries give expression to how might we create conditions for truth, beauty, and justice to emerge in our communities, in the systems that we work in, that govern us and that make way for our individual collective humanity? The time is ripe to ask what are the diverse structures, systems and expressions of an evolving humanity where justice, grace, beauty and truth take new shapes to meet unseen demands placed on adults around the world and what role adult education will play

Probability distribution of magnetization in the one-dimensional Ising model: Effects of boundary conditions

Finite-size scaling functions are investigated both for the mean-square magnetization fluctuations and for the probability distribution of the magnetization in the one-dimensional Ising model. The scaling functions are evaluated in the limit of the temperature going to zero (T -> 0), the size of the system going to infinity (N -> oo) while N[1-tanh(J/k_BT)] is kept finite (J being the nearest neighbor coupling). Exact calculations using various boundary conditions (periodic, antiperiodic, free, block) demonstrate explicitly how the scaling functions depend on the boundary conditions. We also show that the block (small part of a large system) magnetization distribution results are identical to those obtained for free boundary conditions.Comment: 8 pages, 5 figure