Variabilité spatiale de la teneur en eau de surface des sols nus par mesures in situ et imagerie radar

National audienceOn présente l'analyse géostatistique de la teneur en eau de surface (0-6 cm de profondeur) collectée les 12 et 13 Mars 2009, sur une quinzaine de parcelles de sol nu d'un petit bassin péri-urbain proche de Lyon. Les mesures in situ, ont été collectées à deux échelles : une échelle locale sur des croix de longueur 20m et un pas d'espace de 1m et une échelle parcellaire sur 3 transects avec un pas de 20m environ. Les résultats montrent une corrélation de quelques m à échelle fine et de 20 à 50m à l'échelle de la parcelle. Après correction du bruit, calibration radiométrique et correction des effets géométriques et de pente, la comparaison des moyennes par parcelles issues de l'image radar TerraSAR-X et des mesures in situ est satisfaisante (R2=0.43) mais l'analyse intra-parcellaire reste à affiner. / This paper presents the geostatistical analysis of surface soil water content (0-6 cm depth), collected on March 12-13 2009, in about 15 bare soil fields located in a small suburban catchment close to Lyon. In situ data were sampled at two scales : a local scale on 20m-long crosses with a space step of about 1m; a field scale, with 3 transects and a space scale of about 20m. The results show a correlation of a few meters at the local scale and of about 20-50m at the field scale. After correction of the noise, radiometric calibration, geometric and slope effect correction, the comparison of the field averages derived from the TerraSAR-X image and of in situ data is satisfactory (R2=0.43), but the intra-field variability should be studied in more details

Risk prediction of major haemorrhage with surgical treatment of live cesarean scar pregnancies

Objective: To evaluate the association between demographic and ultrasound variables and major intra-operative blood loss during surgical transcervical evacuation of live caesarean scar pregnancies. Study Design: This was a retrospective cohort study conducted in a tertiary referral center between 2008 and 2019. We included all women diagnosed with a live caesarean scar ectopic pregnancy who chose to have surgical management in the study center. A preoperative ultrasound was performed in each patient. All women underwent transcervical suction curettage under ultrasound guidance. Our primary outcome was the rate of postoperative blood transfusion. The secondary outcomes were estimated intra-operative blood loss (ml), rate of retained products of conception, need for repeat surgery, need for uterine artery embolization and hysterectomy rate. Descriptive statistics were used to describe the variables. Univariate and multivariable logistic regression models were constructed using the relevant covariates to identify the significant predictors for severe blood loss. Results: During the study period, 80 women were diagnosed with a live caesarean scar pregnancy, of whom 62 (78%) opted for surgical management at our center. The median crown-rump length was 9.3 mm (range 1.4–85.7). Median blood loss at the time of surgery was 100 ml (range, 10–2300), and six women (10%; 95%CI 3.6–20) required blood transfusion. Crown-rump length and presence of placental lacunae were significant predictive factors for the need for blood transfusion and blood loss > 500 ml at univariate analysis (p < .01); on multivariate analysis, only crown-rump length was a significant predictor for need for blood transfusion (OR = 1.072; 95% CI 1.02–1.11). Blood transfusion was required in 6/18 (33%) cases with the crown-rump length ≥ 23 mm (≥9+0 weeks of gestation), but in none of 44 women presenting with a crown-rump length < 23 mm (p < .01). Conclusion: The risk of severe intraoperative bleeding and need for blood transfusion during or after surgical evacuation of live caesarean scar pregnancies increases with gestational age and is higher in the presence of placental lacunae. One third of women presenting at ≥ 9 weeks of gestation required blood transfusion and their treatment should be ideally arranged in specialized tertiary centers

Development of the utero-placental circulation in cesarean scar pregnancies: A case-control study

BACKGROUND: Cesarean scar pregnancies (CSP) are at high risk of pregnancy complications including placenta previa with antepartum hemorrhage, placenta accreta spectrum (PAS) and uterine rupture. OBJECTIVE: To evaluate the development of the utero-placental circulation in the first half of pregnancy in ongoing CSP and compare it to pregnancies implanted in the lower uterine segment above a prior cesarean section scar with no evidence of PAS at delivery. MATERIAL AND METHODS: This was a retrospective case-control study conducted in two tertiary referral centers. The study group included 27 women diagnosed with a live caesarean scar pregnancy in the first trimester of pregnancy who elected to conservative management. The control group included 27 women diagnosed with a low-lying/placenta previa at 19-22 weeks of gestation who had a first and an early second trimester ultrasound examinations. In both groups, the first ultrasound examination was carried out at 6-10 weeks to establish pregnancy location, viability and to confirm the gestational age. The utero-placental and intra-placental vasculatures were examined using color Doppler imaging (CDI) and described semi quantitatively using CDI score 1-4. The remaining myometrial thickness (RMT) was recorded in the study group whereas in the controls the ultrasound features of prior cesarean scar were noted including the presence of a niche. Both CSP and controls had also ultrasound examinations at 11-14 and 19-22 weeks of gestation. RESULTS: The mean CDI vascularity score at the 6-10 weeks ultrasound examination was significantly (P <.001) higher in the CSP group than in the controls. The high vascularity scores 3 and 4 were recorded in 20/27 (74%) cases of the CSP group. There was no vascularity score of 4 and only 3/27 (11%) controls had vascularity score of 3. In 15/27 (55.6%) CSPs the RMT was < 2 mm. At the 11-14 weeks ultrasound examination, there was no significant difference between the groups for the number of cases with increased subplacental vascularity but 12 CSPs (44%) presented with one or more placental lacunae whereas there was no case with lacunae in the controls. In the 18 CSP that progressed into the third trimester, ten were diagnosed with placenta previa creta at birth, including 4 creta and 6 increta. At the 19-22 weeks ultrasound examination, eight of the ten PAS presented with subplacental hypervascularity out of which, six showed also placental lacunae. CONCLUSION: The vascular changes in the utero-placental and intervillous circulations in CSPs are due to the loss of the normal uterine structure in the scar area and the development of placental tissue in proximity of large diameter arteries of the outer uterine wall. The intensity of these vascular changes, development of PAS and risk of uterine rupture depend on the RMT of the cesarean scar defect at the start of pregnancy. A better understanding of the pathophysiology of the utero-placental vascular changes associated with CSP should help in identifying those cases that may develop major complications and thus contribute to counselling women about the risks associated with different management strategies

Physical resolution of tubal ectopic pregnancy on ultrasound imaging following successful expectant management

RESEARCH QUESTION What is the time required for complete physical resolution of tubal ectopic pregnancies diagnosed on ultrasound imaging in women undergoing successful expectant management? DESIGN A prospective observational cohort study of 177 women who had successful expectant management of tubal ectopic pregnancy, who attended a single Early Pregnancy Unit between January 2014 and December 2018. All participants were monitored until their serum β-hCG dropped to non-pregnant levels and with two-weekly follow-up ultrasound scans until resolution of the pregnancy. RESULTS 112/177 (63.8%, 95% CI 56.3-70.9) of tubal ectopic pregnancies were indiscernible on ultrasound 2 weeks after serum β-hCG had returned to non-pregnant levels. In 8/177 (4.5%, 95% CI 2.0-8.7) physical resolution took longer than 78 days. There was a positive correlation between biochemical and physical resolution of tubal ectopic pregnancy (r=0.21, p=0.006). CONCLUSIONS Physical resolution of tubal ectopic pregnancy is often prolonged and is positively correlated with initial and maximum β-hCG levels. Our results indicate that β-hCG resolution cannot be used as the end-point of expectant management of tubal ectopic pregnancy, which should be considered when counselling women and planning for future pregnancies. KEY MESSAGE In a significant proportion, physical resolution of tubal ectopic pregnancy takes several weeks following the return of serum β-hCG to non-pregnant levels. Women should be advised to delay trying for another pregnancy for three months, to avoid resolving pregnancies being misdiagnosed as new ones and to reduce the theoretical risk of recurrent ectopic, due to temporary tubal blockage by the resolving trophoblast

Impact of location on placentation in live tubal and cesarean scar ectopic pregnancies

INTRODUCTION: The objective of this study was to evaluate the impact of implantation outside the normal intra-uterine endometrium on development of the gestational sac. METHODS: We reviewed and compared the ultrasound measurements and vascularity score around the gestational sac in 69 women diagnosed with a live tubal ectopic pregnancy (TEP) and 54 with a cesarean scar ectopic pregnancy (CSP) at 6-11 weeks of gestation who were certain of their last menstrual period. RESULTS: The rate of a fetus with a cardiac activity in the study population was significantly (P < 0.001) higher in CSPs than in TEPs. The median maternal age, gravidity and parity were significantly (P =.005; P < 0.001 and P < 0.001, respectively) lower in the TEP than in the CSP group. The number of gestational sac size <5th centile for gestational age was significantly (P < 0.001) higher in the TEP than in the CSP group. There were no differences between the groups for the other ultrasound measurements. In cases matched for gestational age, the gestational sac size was significantly (P < 0.001) smaller in the TEP compared to the CSP group. There was a significant (P < 0.001) difference in the distribution of blood flow score with CSP presenting with higher incidence of moderate and high vascularity than TEP. DISCUSSION: Both TEP and CSP are associated with a higher rate of miscarriage than intrauterine pregnancies and the slow development of the gestation sac is more pronounced in TEPs probably as a consequence of a limited access to decidual gland secretions

In search of the most mysterious orthopteran of Europe: the Reed cricket Natula averni (Orthoptera: Gryllidae).

In the last few years a lot of new information has become available on Natula averni. As the common name we propose Reed cricket, because the species was found almost exclusively in reed beds. Recent findings show that this species is more abundant than previously thought. The species can easily be found with knowledge of distribution, habitat and song, all described in this publication. Nevertheless a lot of questions remain about the taxonomy. We hope that information gathered after this publication will help us to reveal the proper identity of reed crickets in Europe

Turbulent separated shear flow control by surface plasma actuator: experimental optimization by genetic algorithm approach

The potential benefits of active flow control are no more debated. Among many others applications, flow control provides an effective mean for manipulating turbulent separated flows. Here, a nonthermal surface plasma discharge (dielectric barrier discharge) is installed at the step corner of a backward-facing step (U&nbsp;0&nbsp;=&nbsp;15&nbsp;m/s,&nbsp;Re&nbsp;h&nbsp;&nbsp;=&nbsp;30,000,&nbsp;Re&nbsp;&theta;&nbsp;&nbsp;=&nbsp;1650). Wall pressure sensors are used to estimate the reattaching location downstream of the step (objective function #1) and also to measure the wall pressure fluctuation coefficients (objective function #2). An autonomous multi-variable optimization by genetic algorithm is implemented in an experiment for optimizing simultaneously the voltage amplitude, the burst frequency and the duty cycle of the high-voltage signal producing the surface plasma discharge. The single-objective optimization problems concern alternatively the minimization of the objective function #1 and the maximization of the objective function #2. The present paper demonstrates that when coupled with the plasma actuator and the wall pressure sensors, the genetic algorithm can find the optimum forcing conditions in only a few generations. At the end of the iterative search process, the minimum reattaching position is achieved by forcing the flow at the shear layer mode where a large spreading rate is obtained by increasing the periodicity of the vortex street and by enhancing the vortex pairing process. The objective function #2 is maximized for an actuation at half the shear layer mode. In this specific forcing mode, time-resolved PIV shows that the vortex pairing is reduced and that the strong fluctuations of the wall pressure coefficients result from the periodic passages of flow structures whose size corresponds to the height of the step model

A modeling approach to assess the hydrological response of small mediterranean catchments to the variability of soil characteristics in a context of extreme events

This paper presents a modeling study aiming at quantifying the possible impact of soil characteristics on the hydrological response of small ungauged catchments in a context of extreme events. The study focuses on the September 2002 event in the Gard region (South-Eastern France), which led to catastrophic flash-floods. The proposed modeling approach is able to take into account rainfall variability and soil profiles variability. Its spatial discretization is determined using Digital Elevation Model (DEM) and a soil map. The model computes infiltration, ponding and vertical soil water distribution, as well as river discharge. In order to be applicable to ungauged catchments, the model is set up without any calibration and the soil parameter specification is based on an existing soil database. The model verification is based on a regional evaluation using 17 estimated discharges obtained from an extensive post-flood investigation. Thus, this approach provides a spatial view of the hydrological response across a large range of scales. To perform the simulations, radar rainfall estimations are used at a 1 km&lt;sup&gt;2&lt;/sup&gt; and 5 min resolution. To specify the soil hydraulic properties, two types of pedotransfer function (PTF) are compared. It is shown that the PTF including information about soil structure reflects better the spatial variability that can be encountered in the field. The study is focused on four small ungauged catchments of less than 10 km&lt;sup&gt;2&lt;/sup&gt;, which experienced casualties. Simulated specific peak discharges are found to be in agreement with estimations from a post-event in situ investigation. Examining the dynamics of simulated infiltration and saturation degrees, two different behaviors are shown which correspond to different runoff production mechanisms that could be encountered within catchments of less than 10 km&lt;sup&gt;2&lt;/sup&gt;. They produce simulated runoff coefficients that evolve in time and highlight the variability of the infiltration capacity of the various soil types. Therefore, we propose a cartography distinguishing between areas prone to saturation excess and areas prone only to infiltration excess mechanisms. The questions raised by this modeling study will be useful to improve field observations, aiming at better understanding runoff generation for these extreme events and examine the possibility for early warning, even in very small ungauged catchments

Genome-Wide microRNA Binding Site Variation between Extinct Wild Aurochs and Modern Cattle Identifies Candidate microRNA-Regulated Domestication Genes

peer-reviewedThe domestication of cattle from the now-extinct wild aurochs (Bos primigenius) involved selection for physiological and behavioral traits, with underlying genetic factors that remain largely unknown. Non-coding microRNAs have emerged as key regulators of the spatio-temporal expression of target genes controlling mammalian growth and development, including in livestock species. During the domestication process, selection of mutational changes in miRNAs and/or miRNA binding sites could have provided a mechanism to generate some of the traits that differentiate domesticated cattle from wild aurochs. To investigate this, we analyzed the open reading frame DNA sequence of 19,994 orthologous protein-coding gene pairs from extant Bos taurus genomes and a single extinct B. primigenius genome. We identified miRNA binding site polymorphisms in the 3′ UTRs of 1,620 of these orthologous genes. These 1,620 genes with altered miRNA binding sites between the B. taurus and B. primigenius lineages represent candidate domestication genes. Using a novel Score Site ratio metric we have ranked these miRNA-regulated genes according to the extent of divergence between miRNA binding site presence, frequency and copy number between the orthologous genes from B. taurus and B. primigenius. This provides an unbiased approach to identify cattle genes that have undergone the most changes in miRNA binding (i.e., regulation) between the wild aurochs and modern-day cattle breeds. In addition, we demonstrate that these 1,620 candidate domestication genes are enriched for roles in pigmentation, fertility, neurobiology, metabolism, immunity and production traits (including milk quality and feed efficiency). Our findings suggest that directional selection of miRNA regulatory variants was important in the domestication and subsequent artificial selection that gave rise to modern taurine cattle