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Giuliano, N., M. L. Annunziata, S. Tagliaferri, F. G. Esposito, O. C. M. Imperato, M. Campanile, M. G. Signorini et A. Di Lieto. « IUGR Management : New Perspectives ». Journal of Pregnancy 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/620976.
Texte intégralRésumé :
Aim of the Study. Analyzing velocimetric (umbilical artery, UA; ductus venosus, DV; middle cerebral artery, MCA) and computerized cardiotocographic (cCTG) (fetal heart rate, FHR; short term variability, STV; approximate entropy, ApEn) parameters in intrauterine growth restriction, IUGR, in order to detect early signs of fetal compromise.Population Study. 375 pregnant women assisted from the 28th week of amenorrhea to delivery and monitored through cCTG and Doppler ultrasound investigation. The patients were divided into three groups according to the age of gestation at the time of delivery, before the 34th week, from 34th to 37th week, and after the 37th week. Data were analyzed in relation to the days before delivery and according to the physiology or pathology of velocimetry. Statistical analysis was performed through thet-test, chi-square test, and Pearson correlation test(P<0.05). Our results evidenced an earlier alteration of UA, DV, and MCA. The analysis between cCTG and velocimetric parameters (the last distinguished into physiological and pathological values) suggests a possible relation between cCTG alterations and Doppler ones. The present study emphasizes the need for an antenatal testing in IUGR fetuses using multiple surveillance modalities to enhance prediction of neonatal outcome.
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Bufalino, L., G. Rizzo, D. Rinaldo, E. Romanini, H. Valensise, D. Arduini et C. Romanini. « Previsione della Preeclampsia nella Gravidanza Gemellare Mediante Velocimetria Doppler Uterina ». Acta geneticae medicae et gemellologiae : twin research 43, no 1-2 (avril 1994) : 115. http://dx.doi.org/10.1017/s0001566000003056.
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AbstractL'incidenza di pre-eclampsia nella gravidanza gemellare è aumentata di circa 5 volte rispetto alle gravidanze singole. La velocimetria Doppler a livello uterino si è dimostrato in popolazioni a rischio, un metodo efficace per identificare precocemente le pazienti a rischio di pre-eclampsia. Non sono disponibili dati a questo riguardo nella gravidanza gemellare.Obiettivi: 1) valutare le differenze negli indici di resistenza delle arterie uterine tra gravidanze singole e gemellari, 2) valutare eventuali differenze in gravidanze gemellari complicate da pre-eclampsia, 3) valutare il valore predittivo della velocimetria Doppler uterina sulla pre-eclampsia in gravidanze gemellari esaminate a 20-24 settimane di gestazione e poi seguite prospettivamente.Disegno dello studio: l'indice di resistenza RI a livello di entrambe le arterie uterine è stato calcolato mediante Doppler colore-pulsato (Ansaldo Hitachi AU590A) nelle seguenti popolazioni: a) 315 gravidanze singole non complicate, b) 96 gravidanze gemellari non complicate, c) 53 gravidanze gemellari complicate da pre-eclampsia, d) 63 gravidanze gemellari valutate a 20-24 settimane di gestazione e non complicate al momento della osservazione.Risultati: 1) sia nelle gravidanze singole che in quelle gemellari i valori di RI decrescono nel corso della gravidanza e i valori presenti nelle gravidanze gemellari a decorso normale sono significativamente inferiori (Anova p < 0.001). 2) le gravidanze gemellari complicate da preeclampsia dimostrano valori di RI lievemente superiori alle gravidanze gemellari non complicate (p <0.05). 3) il valore predittivo sulla preeclampsia delle arterie uterine a 20-24 settimane è risultato inadeguato (k = 0.24).Conclusioni: la velocimetria Doppler delle arterie uterine è risultata di scarsa utilità clinica nel prevedere la preeclampsia nelle gravidanze gemellari.
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Colloi, D., et G. Savare. « Valore E Limiti Della Velocimetria Doppler Nella Diagnosi Di Torsione Di Funicolo Di Vecchia Data ». Urologia Journal 53, no 1 (février 1986) : 126–29. http://dx.doi.org/10.1177/039156038605300126.
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Oliveira, M. E. F., Y. Tarasevych, W. R. R. Vicente et P. M. Bartlewski. « 195 Are the Spectral Doppler Indices of the Ovarian Arteries Predictive of Ovulatory Responses and Embryo Yields in Superovulated Ewes ? » Reproduction, Fertility and Development 30, no 1 (2018) : 238. http://dx.doi.org/10.1071/rdv30n1ab195.
Texte intégralRésumé :
Increased uterine and ovarian blood flow seems to be related to the effectiveness of ovarian response to hormonal superstimulation in mares (Witt et al. 2012 Theriogenology 77, 1406-1414). Similar studies do not exist for sheep. Nineteen Santa Inês ewes were subjected to a 9-day CIDR® priming and superovulatory (SOV) treatment with 200 mg of porcine (p)FSH per ewe given twice daily for 4 consecutive days in decreasing doses and initiated 6 days after CIDR® insertion. Ten ewes received an IM injection of oestradiol benzoate (EB, 350 μg) at the time of CIDR® insertion (group E); the remaining animals served as controls (group C). The ewes were placed in a pen with rams for 3 days after CIDR® removal. The embryos were recovered surgically 6 days after the CIDR® removal. Transrectal ultrasonographic examinations (Doppler mode) using MyLab VET 30 scanner (Esaote, Genoa, Italy) equipped with a linear-array (6- to 8-MHz) transducer were performed once a day throughout the SOV treatment (Days 1 to 4) to determine the velocimetric indices of the left and right ovarian arteries: flow velocity integral (FVI); peak systolic velocity (SVp); mean velocity (Vm); end-diastolic velocity (EDV); vascular resistance index [RI = (SVp – EDV)/SVp]; and pulsatility index [PI = (SVp – EDV)/Vm]. All spectral data were obtained from a longitudinal subovarian segment of the ovarian artery using a gate ranging from 2 to 3 mm (~two-thirds of the vessel’s diameter) and insonation angle ≤60°. There were no differences (P > 0.05) in ovarian responses and embryo yields/quality between left and right ovaries/uterine horns flashed or between EB-treated and control ewes. Mean EDV and Vm were greater (P < 0.05) in group C compared with group E on Days 1 and 2, and mean Vp was greater (P < 0.05) in group C ewes on Day 3 of the SOV treatment. In group E, there were 5 significant correlations between the spectral Doppler indices (RI, PI, and EDV) of the ovarian arteries recorded on Days 2 and 4 and SOV responses (numbers of degenerated embryos, unfertilized eggs, and luteinized unovulated follicles characterised by a lack of ovulatory stigmata). In group C, 7 significant correlations were found between Vp, EDV, Vm, and RI on Days 1, 2, and 3 and numbers/percentages of degenerated embryos, numbers of prematurely regressed luteal structures (pale, ≤5 mm in diameter), and embryo viability rates (percentage of transferrable quality embryos). When ultrasonographic and SOV data were analysed separately for the left and right ovarian artery/uterine horn, multiple significant correlations were found between the velocimetric indices and SOV responses but they varied among days, the 2 ovaries, and the 2 groups of animals studied. These results may be interpreted to suggest that intrinsic gonadal factors remain a significant barrier precluding the prediction of SOV outcomes from haemodynamic changes in ovine ovarian arteries. Velocimetric indices determined in the ovarian arteries appear to have limited prognostic value during the application of different SOV protocols in ewes.
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Isella, Luana, Stefano Podestà, Sonia Resemini, Marco Pasta et Claudio Eva. « The Relationship between Damage and Peak Accelerations in Ripabottoni during the 2002 Molise, Italy, Earthquake ». Earthquake Spectra 20, no 1_suppl (juillet 2004) : 119–30. http://dx.doi.org/10.1193/1.1766307.
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After the main shocks of the 2002 Molise, Italy, earthquake sequence, the University of Genoa Geophysical Section (Dip. Te. Ris) installed a temporary seismic network, composed of two velocimetric and two accelerometric stations, in the village of Ripabottoni (Campobasso Province), near the epicentral area. These stations were implemented in the regional network of seismic instruments installed after November 1 by geophysical institutes from Rome and Trieste, Italy. The network registered more than 2,000 aftershocks with magnitudes ranging from 1.0–4.0. A DISEG Group also participated in a survey coordinated by the Larino Emergency Operations Center to examine damaged churches. The preliminary data, which correlates the waveform of the available recordings from aftershocks with damaged masonry pillars, indicates that the damage may relate not only to the intrinsic vulnerability of this building type, but also to the high energy in the high frequency range observed in the vertical component of the earthquakes.
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Worku, Keduse, Songhu Wang, Jennifer Burt, Malena Rice, Xian-Yu Wang, Yong-Hao Wang, Steven S. Vogt et al. « Revisiting the Full Sets of Orbital Parameters for the XO-3 System : No Evidence for Temporal Variation of the Spin–Orbit Angle ». Astronomical Journal 163, no 4 (10 mars 2022) : 158. http://dx.doi.org/10.3847/1538-3881/ac4e1a.
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Abstract We present 12 new transit light curves and 16 new out-of-transit radial-velocity measurements for the XO-3 system. By modeling our newly collected measurements together with archival photometric and Doppler velocimetric data, we confirmed the unusual configuration of the XO-3 system, which contains a massive planet ( M P = 11.92 − 0.63 + 0.59 M J ) on a relatively eccentric ( e = 0.2853 − 0.0026 + 0.0027 ) and short-period (3.19152 ± 0.00145 day) orbit around a massive star ( M * = 1.219 − 0.095 + 0.090 M ⊙ ). Furthermore, we find no strong evidence for a temporal change of either V sin i * (and by extension, the stellar spin vector of XO-3), or the transit profile (and thus orbital angular momentum vector of XO-3b). We conclude that the discrepancy in previous Rossiter–McLaughlin measurements (70.0° ± 15.0°; Hébrard et al. 2008; 37.3° ± 3.7°; Winn et al. 2009; 37.3° ± 3.0°; Hirano et al. 2011) may have stemmed from systematic noise sources.
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Ponzo, Felice Carlo, Chiara Iacovino, Rocco Ditommaso, Manuela Bonano, Riccardo Lanari, Francesco Soldovieri, Vincenzo Cuomo, Francesca Bozzano, Paolo Ciampi et Matteo Rompato. « Transport Infrastructure SHM Using Integrated SAR Data and On-Site Vibrational Acquisitions : “Ponte Della Musica–Armando Trovajoli” Case Study ». Applied Sciences 11, no 14 (15 juillet 2021) : 6504. http://dx.doi.org/10.3390/app11146504.
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This work presents the first results obtained by applying in situ and remote-sensing methodologies to monitor the Ponte della Musica-Armando Trovajoli located in Rome, within the activities of the WP6 “Structural Health Monitoring and Satellite Data” 2019-21 Reluis Project. In particular, the use of remote-sensing Differential Synthetic Aperture Radar (SAR) Interferometry (DInSAR) measurements provided a spatial map of the displacement of the investigated infrastructure and the corresponding time-series, with the aim of monitoring deformation phenomena, focusing on the local scale analysis, which produces suitable results for urban monitoring and damage assessment. The DInSAR results have been integrated with the identification of the dynamic characteristics of the bridge, performed through an experimental campaign of ambient vibration measurements carried out in October 2020 and with the local-scale definition of the engineering geological setting of the foundation soil. The subsoil of the bridge is constituted by more than 50 m of recent alluvial deposits resting on Pliocene stiff clay acting as a geological bedrock. A substantially stable behavior of the bridge structural elements has been observed based on the analysis of both satellite and velocimetric data. This case represents a good example about how the integration of in situ sensors with remotely sensed data and the exploitation of a detailed knowledge regarding the on-site conditions represent a key factor for a sustainable structural and infrastructural monitoring and can support the planning both of maintenance and safety management.
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Jones, Matías I., Rafael Brahm, Nestor Espinoza, Songhu Wang, Avi Shporer, Thomas Henning, Andrés Jordán et al. « HD 2685 b : a hot Jupiter orbiting an early F-type star detected by TESS ». Astronomy & ; Astrophysics 625 (mai 2019) : A16. http://dx.doi.org/10.1051/0004-6361/201834640.
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We report on the confirmation of a transiting giant planet around the relatively hot (Teff = 6801 ± 76 K) star HD 2685, whose transit signal was detected in Sector 1 data of NASA’s TESS mission. We confirmed the planetary nature of the transit signal using Doppler velocimetric measurements with CHIRON, CORALIE, and FEROS, as well as using photometric data obtained with the Chilean-Hungarian Automated Telescope and the Las Cumbres Observatory. From the joint analysis of photometry and radial velocities, we derived the following parameters for HD 2685 b: P = 4.12688−0.00004+0.00005 days, e = 0.091−0.047+0.039, MP = 1.17 ± 0.12 MJ, and RP =1.44 ± 0.05 RJ. This system is a typical example of an inflated transiting hot Jupiter in a low-eccentricity orbit. Based on the apparent visual magnitude (V = 9.6 mag) of the host star, this is one of the brightest known stars hosting a transiting hot Jupiter, and it is a good example of the upcoming systems that will be detected by TESS during the two-year primary mission. This is also an excellent target for future ground- and space-based atmospheric characterization as well as a good candidate for measuring the projected spin-orbit misalignment angle through the Rossiter–McLaughlin effect.
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Triaud, Amaury H. M. J., Matthew R. Standing, Neda Heidari, David V. Martin, Isabelle Boisse, Alexandre Santerne, Alexandre C. M. Correia et al. « BEBOP III. Observations and an independent mass measurement of Kepler-16 (AB) b – the first circumbinary planet detected with radial velocities ». Monthly Notices of the Royal Astronomical Society 511, no 3 (23 février 2022) : 3561–70. http://dx.doi.org/10.1093/mnras/stab3712.
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ABSTRACT The radial velocity method is amongst the most robust and most established means of detecting exoplanets. Yet, it has so far failed to detect circumbinary planets despite their relatively high occurrence rates. Here, we report velocimetric measurements of Kepler-16A, obtained with the SOPHIE spectrograph, at the Observatoire de Haute-Provence’s 193cm telescope, collected during the BEBOP survey for circumbinary planets. Our measurements mark the first radial velocity detection of a circumbinary planet, independently determining the mass of Kepler-16 (AB) b to be $0.313 \pm 0.039\, {\rm M}_{\rm Jup}$, a value in agreement with eclipse timing variations. Our observations demonstrate the capability to achieve photon-noise precision and accuracy on single-lined binaries, with our final precision reaching $\rm 1.5~m\, s^{-1}$ on the binary and planetary signals. Our analysis paves the way for more circumbinary planet detections using radial velocities which will increase the relatively small sample of currently known systems to statistically relevant numbers, using a method that also provides weaker detection biases. Our data also contain a long-term radial velocity signal, which we associate with the magnetic cycle of the primary star.
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Barbosa, Claudia C., Mírley B. Souza, Sarah R. R. A. Scalercio, Ticiana F. P. Silva, Sheyla F. S. Domingues et Lúcia D. M. Silva. « Ovarian and uterine periovulatory Doppler ultrasonography in bitches ». Pesquisa Veterinária Brasileira 33, no 9 (septembre 2013) : 1144–50. http://dx.doi.org/10.1590/s0100-736x2013000900016.
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This paper aims to describe the uterine and ovarian ultrasonographic characteristics and Doppler velocimetric features of their arteries in bitches during the periovulatory period. Fifteen estrous cycles in 10 animals were evaluated. The ultrasonographic characteristics, resistance indices (RI) and pulsatility indices (PI) of the uterus and ovaries in each animal were recorded 5 days before and after ovulation (D0). The data were statistically analyzed, and the results were expressed as the mean ± standard error of mean (P<0.05). In results the ultrasonographic features of the uterus were the same on all of the cycles and evaluated days. The uterus had an average diameter of 0.85±0.02cm. An increase in the volume of the ovaries and the diameter of the ovarian follicles were measured. Ovaries had a volume of 0.64±0.06cm³, and the follicles cavities had a diameter of 0.46 ± 0.01 cm on the day of ovulation. After ovulation, it was observed that some follicles not collapse in some cycles. Two days prior to ovulation, the uterine blood perfusion decreased. This decrease remained unchanged until ovulation. Following ovulation, we measured a gradual increase in the uterine perfusion and in the ovarian artery. This artery directed blood flow to the ovaries and increased the intra-ovarian perfusion on the day after ovulation. In conclusion, specific features are observed in the uterus and ovarian ultrasound image and Doppler values of their arteries presented on the periovulatory days and when associated allow to estimate more accurately the date of ovulation.
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Scala, Antonio, Guido Maria Adinolfi, Matteo Picozzi, Francesco Scotto di Uccio, Gaetano Festa, Grazia De Landro, Enrico Priolo, Stefano Parolai, Rosario Riccio et Marco Romanelli. « Monitoring the Microseismicity through a Dense Seismic Array and a Similarity Search Detection Technique : Application to the Seismic Monitoring of Collalto Gas-Storage, North Italy ». Energies 15, no 10 (11 mai 2022) : 3504. http://dx.doi.org/10.3390/en15103504.
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Seismic monitoring in areas where induced earthquakes could occur is a challenging topic for seismologists due to the generally very low signal to noise ratio. Therefore, the seismological community is devoting several efforts to the development of high-quality networks around the areas where fluid injection and storage and geothermal activities take place, also following the national induced seismicity monitoring guidelines. The use of advanced data mining strategies, such as template matching filters, auto-similarity search, and deep-learning approaches, has recently further fostered such monitoring, enhancing the seismic catalogs and lowering the magnitude of completeness of these areas. In this framework, we carried out an experiment where a small-aperture seismic array was installed within the dense seismic network used for monitoring the gas reservoir of Collalto, in North Italy. The continuous velocimetric data, acquired for 25 days, were analysed through the application of the optimized auto-similarity search technique FAST. The array was conceived as a cost-effective network, aimed at integrating, right above the gas storage site, the permanent high-resolution Collalto Seismic Network. The analysis allowed to detect micro-events down to magnitude Ml = −0.4 within a distance of ~15 km from the array. Our results confirmed that the system based on the array installation and the FAST data analysis might contribute to lowering the magnitude of completeness around the site of about 0.7 units.
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Xu, Haoxuan, Jianping Wang, Ya Zhang, Guo Zhang et Zhaolong Xiong. « Subgrid Variational Optimized Optical Flow Estimation Algorithm for Image Velocimetry ». Sensors 23, no 1 (30 décembre 2022) : 437. http://dx.doi.org/10.3390/s23010437.
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The variational optical flow model is used in this work to investigate a subgrid-scale optimization approach for modeling complex fluid flows in image sequences and estimating their two-dimensional velocity fields. To solve the problem of lack of sub-grid small-scale structure information in variational optical flow estimation, we combine the motion laws of incompressible fluids. Introducing the idea of large eddy simulation, the instantaneous motion can be decomposed into large-scale motion and a small-scale turbulence in the data term. The Smagorinsky model is used to model and solve the small-scale turbulence. The improved subgrid scale Horn–Schunck (SGS-HS) optical flow algorithm provides better results in velocity field estimation of turbulent image sequences than the traditional Farneback dense optical flow algorithm. To make the SGS-HS algorithm equally competent for the open channel flow measurement task, a velocity gradient constraint is chosen for the canonical term of the model, which is used to improve the accuracy of the SGS-HS algorithm in velocimetric experiments in the case of the relatively uniform flow direction of the open channel flow field. The experimental results show that our algorithm has better performance in open channel velocimetry compared with the conventional algorithm.
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Onwudiegwu, Chiemelie, Ademola Adekanmi, Bolutife Olusanya, Olatunji Lawal, Babatunde Adedokun, Imran Morhason-Bello et Adesina Oladokun. « Case-control study on ocular changes and ophthalmic Doppler velocimetric indices among preeclamptic and normotensive pregnant women in Ibadan, Nigeria ». BMJ Open Ophthalmology 5, no 1 (septembre 2020) : e000550. http://dx.doi.org/10.1136/bmjophth-2020-000550.
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ObjectiveTo compare the ocular changes and Doppler velocimetric indices in preeclamptic and normotensive pregnant women.Methods and analysisThis was a case-control study of 71 preeclamptic women and 72 parity-matched normotensive pregnant women conducted at the University College Hospital, Ibadan, Nigeria. Demographic data were obtained using questionnaires. All participants had visual acuity assessment, funduscopy, intraocular pressure measurement and orbital Doppler ultrasonography. The differences in parameters between the two groups were tested using Student’s t-test for quantitative variables and χ2 tests for categorical variables.ResultsThere were no significant differences between cases and controls with respect to sociodemographic variables. The mean pulsatility index was 1.35±0.46 in cases and 2.1±0.4 in controls (p<0.001); the resistivity index was 0.7±0.18 in cases and 0.83±0.27 among the controls (p=0.01). A similar pattern was observed in the peak systolic velocity (p<0.001) and the peak ratio (p<0.001). There was no significant difference between the groups concerning end-diastolic velocity (p=0.535). Three preeclampsia patients (5.2%) had abnormalities on funduscopy compared with none of the controls. Preeclamptic women had significantly higher intraocular pressures in both eyes at baseline and at 24 hours post delivery.ConclusionThis study demonstrated lower Doppler velocimetry and impedance parameters and higher intraocular pressure among preeclampsia cases compared with controls. Abnormal funduscopic findings were observed in a few preeclamptic women and none among the controls. Ophthalmic artery Doppler parameters could be useful in identifying those women who are likely to suffer preeclampsia and its complications.
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Mascandola, Claudia, Giovanni Lanzano et Francesca Pacor. « Consistency Check of ITACAext, the Flatfile of the Italian Accelerometric Archive ». Geosciences 12, no 9 (6 septembre 2022) : 334. http://dx.doi.org/10.3390/geosciences12090334.
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We present the results of a consistency check performed over a flatfile of accelerometric data extracted from the ITalian ACcelerometric Archive (ITACA), enriched with velocimetric records of events with magnitude M < 4.0. The flatfile, called ITACAext, includes 31,967 waveforms from 1709 shallow crustal earthquakes, in the magnitude range from 3.0 to 6.9, and occurred in the period of 1972–2019 in Italy. The consistency check is carried out by decomposing the residuals obtained from a reference ground motion model, for the ordinates of the 5% damped acceleration response spectra. The residual components are subsequently analyzed to identify a list of events, stations, and records that significantly deviate from the median trends predicted by the model. The results indicate that about 10% of events and stations are outliers, while only 1% of the waveforms present anomalous amplitudes. The asymmetrical azimuthal coverage of seismic stations around the epicenter is the most common issue that can affect the estimates of the repeatable event residual term. On the other hand, peculiarities in the site-response or wrong estimates of the soil parameters (i.e., the average shear-wave velocity in the first 30 m of the subsoil) are the main issues related to the repeatable station residuals. Finally, single records can show large residuals because of issues related to signal acquisition (e.g., multiple events, noisy records) or possible near-source effects (e.g., rupture directivity).
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Vixège, Florian, Alain Berod, Yunyun Sun, Simon Mendez, Olivier Bernard, Nicolas Ducros, Pierre-Yves Courand, Franck Nicoud et Damien Garcia. « Physics-constrained intraventricular vector flow mapping by color Doppler ». Physics in Medicine & ; Biology 66, no 24 (16 décembre 2021) : 245019. http://dx.doi.org/10.1088/1361-6560/ac3ffe.
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Abstract Color Doppler by transthoracic echocardiography creates two-dimensional fan-shaped maps of blood velocities in the cardiac cavities. It is a one-component velocimetric technique since it only returns the velocity components parallel to the ultrasound beams. Intraventricular vector flow mapping (iVFM) is a method to recover the blood velocity vectors from the Doppler scalar fields in an echocardiographic three-chamber view. We improved our iVFM numerical scheme by imposing physical constraints. The iVFM consisted in minimizing regularized Doppler residuals subject to the condition that two fluid-dynamics constraints were satisfied, namely planar mass conservation, and free-slip boundary conditions. The optimization problem was solved by using the Lagrange multiplier method. A finite-difference discretization of the optimization problem, written in the polar coordinate system centered on the cardiac ultrasound probe, led to a sparse linear system. The single regularization parameter was determined automatically for non-supervision considerations. The physics-constrained method was validated using realistic intracardiac flow data from a patient-specific computational fluid dynamics (CFD) model. The numerical evaluations showed that the iVFM-derived velocity vectors were in very good agreement with the CFD-based original velocities, with relative errors ranged between 0.3% and 12%. We calculated two macroscopic measures of flow in the cardiac region of interest, the mean vorticity and mean stream function, and observed an excellent concordance between physics-constrained iVFM and CFD. The capability of physics-constrained iVFM was finally tested with in vivo color Doppler data acquired in patients routinely examined in the echocardiographic laboratory. The vortex that forms during the rapid filling was deciphered. The physics-constrained iVFM algorithm is ready for pilot clinical studies and is expected to have a significant clinical impact on the assessment of diastolic function.
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Bourrier, V., X. Dumusque, C. Dorn, G. W. Henry, N. Astudillo-Defru, J. Rey, B. Benneke et al. « The 55 Cancri system reassessed ». Astronomy & ; Astrophysics 619 (30 octobre 2018) : A1. http://dx.doi.org/10.1051/0004-6361/201833154.
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Orbiting a bright, nearby star the 55 Cnc system offers a rare opportunity to study a multiplanet system that has a wide range of planetary masses and orbital distances. Using two decades of photometry and spectroscopy data, we have measured the rotation of the host star and its solar-like magnetic cycle. Accounting for this cycle in our velocimetric analysis of the system allows us to revise the properties of the outermost giant planet and its four planetary companions. The innermost planet 55 Cnc e is an unusually close-in super-Earth, whose transits have allowed for detailed follow-up studies. Recent observations favor the presence of a substantial atmosphere yet its composition, and the nature of the planet, remain unknown. We combined our derived planet mass (Mp = 8.0 ± 0.3 MEarth) with refined measurement of its optical radius derived from HST/STIS observations (Rp = 1.88 ± 0.03 REarth over 530–750 nm) to revise the density of 55 Cnc e (ρ = 6.7 ± 0.4 g cm−3). Based on these revised properties we have characterized possible interiors of 55 Cnc e using a generalized Bayesian model. We confirm that the planet is likely surrounded by a heavyweight atmosphere, contributing a few percents of the planet radius. While we cannot exclude the presence of a water layer underneath the atmosphere, this scenario is unlikely given the observations of the planet across the entire spectrum and its strong irradiation. Follow-up observations of the system in photometry and in spectroscopy over different time-scales are needed to further investigate the nature and origin of this iconic super-Earth.
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Lanzano, Giovanni, Chiara Felicetta, Francesca Pacor, Daniele Spallarossa et Paola Traversa. « Methodology to identify the reference rock sites in regions of medium-to-high seismicity : an application in Central Italy ». Geophysical Journal International 222, no 3 (25 mai 2020) : 2053–67. http://dx.doi.org/10.1093/gji/ggaa261.
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SUMMARY To evaluate the site response using both empirical approaches (e.g. standard spectral ratio, ground motion models (GMMs), generalized inversion techniques, etc.) and numerical 1-D/2-D analyses, the definition of the reference motion, that is the ground motion recorded at stations unaffected by site-effects due to topographic, stratigraphic or basin effects, is needed. The main objective of this work is to define a robust strategy to identify the seismic stations that can be considered as reference rock sites, using six proxies for the site response: three proxies are related to the analysis of geophysical and seismological data (the repeatable site term from the residual analysis, the resonance frequencies from horizontal-to-vertical spectral ratios on noise or earthquake signals, the average shear wave velocity in the first 30 m); the remaining ones concern geomorphological and installation features (outcropping rocks or stiff soils, flat topography and absence of interaction with structures). We introduce a weighting scheme to take into account the availability and the quality of the site information, as well as the fulfillment of the criterion associated to each proxy. We also introduce a hierarchical index, to take into account the relevance of the proposed proxies in the description of the site effects, and an acceptance threshold for reference rock sites identification. The procedure is applied on a very large data set, composed by accelerometric and velocimetric waveforms, recorded in Central Italy in the period 2008–2018. This data set is composed by more than 30 000 waveforms relative to 450 earthquakes in the magnitude range 3.2–6.5 and recorded by more than 450 stations. A total of 36 out of 133 candidate stations are identified as reference sites: the majority of them are installed on rock with flat topography, but this condition is not sufficient to guarantee the absence of amplifications, especially at high frequencies. Seismological analyses are necessary to exclude stations affected by resonances. We test the impact of using these sites by calibrating a GMMs. The results show that for reference rock sites the median predictions are reduced down to about 45 per cent at short periods in comparison to the generic rock motions.
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Mello, Fabíola Peixoto da Silva, Verônica Noriega Torres, Renata Ferreira Cunha, Tatiane Meirelles, Aline Silva Gouvêa, Niesca Goulart Sanchotene, Elisa Barp Neuwald, Juliana Pereira Matheus, Fernanda Bastos de Mello et João Roberto Braga de Mello. « Sedation Effect of Acepromazine and Butorphanol in Dopplervelocimetric Parameters in Great Abdominal Arteries and Femoral Artery in Dogs ». Acta Scientiae Veterinariae 44, no 1 (19 mars 2018) : 7. http://dx.doi.org/10.22456/1679-9216.81172.
Texte intégralRésumé :
Background: Doppler ultrasound is a non-invasive diagnostic imaging technique that allows vascular anatomical and dynamics evaluation. Each artery has flow velocity profiles and different Doppler spectrum. The purpose of this study was to determine if sedation with acepromazine and butorphanol in dogs alters Doppler velocimetric values and diameter from abdominal aorta, celiac, mesenteric cranial, renal, external iliac and femoral arteries of healthy dogs.Materials, Methods & Results: Twenty healthy female dogs, aged 1 to 5 years, with body weight ranging from 10 to 25 kg, were evaluated with Doppler ultrasound in order to obtain: peak systolic velocity, end diastolic velocity, time average medium velocity, time average maximum velocity, resistive index, pulsatility index, and diameter from abdominal aorta, celiac, mesenteric cranial, renal, external iliac and femoral arteries. The same animals were sedated with acepromazine (0.02 mg/kg) and buthorphanol (0.4 mg/kg) and the same parameters were reevaluated. The heart rate was also measured. The study was approved by the Animal Ethics Committee of UFRGS, under the 25552 protocol, and the owners signed an informed consent form. Statistical analysis was performed with pared t test.The heart rate was statistically significant different, 98 ± 20.13 bpm before and 79 ± 17.74 after sedation. The exam was done before and after sedation in all selected vessels, except the celiac and cranial mesenteric artery, which were possible only in 35% and 45% respectively. All measured arteries exhibit difference in at least two of the analyzed parameters, except femoral artery, that only diameter was different.Discussion: Each vessel was selected because of its importance, and each of them has its own characteristic waveform. Changes in patterns of flow velocity of the celiac artery and mesenteric can help to determine the physiological condition of the gastrointestinal tract; in the case of renal arteries are associated with diseases involving parenchyma and; thrombosis in the aorta and the iliac and femoral arteries may be difficult to evaluate without the Doppler image. Examination of the AC and AMC before and after sedation not could be performed in all animals, maybe because the present work was carried out with only fasting requirement, without using dimethicone, and one of the difficulties encountered was the presence of gas in the gastrointestinal tract. Another factor that may have contributed to these findings is that the acute stress of containment and other environmental factors can cause release of vasopressin and leads to vasoconstriction of the splanchnic vascular bed. The dopplervelocimetric data found in celiac, mesenteric cranial, renal and femoral arteries in non-sedated animals was similar to what was described by other authors. Although all dogs demonstrated relaxation during the exam, this sedation protocol alters the values found with Doppler ultrasound in the selected vessels, except femoral artery, which caused only increase of diameter. The Doppler differences found can be a consequence of a decrease in heart rate associated with longer cycle length, and therefore, larger diastolic volume with vessels that stayed with same diameter, or in case of caudal abdominal aorta, that reduced the diameter. This study compared the dopplervelocimetric values to the ones described by other authors in non-sedated animals and demonstrated that although acepromazine and buthorphanol are a good option to sedate dogs to perform ultrasound exam, they alter the Doppler values from aorta abdominal, celiac, cranial mesenteric, renal, external iliac arteries and the femoral artery diameter.
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De Souza, Carolina Menezes Suassuna, Iorrany Maria Oliveira Lobo Calou, Lívia Matos Albuquerque De Andrade, Natália Matos Souza Azevedo et Marlon de Vasconcelos Azevedo. « Determination of Doppler velocimetric measurements of the median artery in horses ». Brazilian Journal of Development, 16 août 2022, 57475–84. http://dx.doi.org/10.34117/bjdv8n8-173.
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Considering the importance of equine culture for the northeast region, the objective was to determine the median artery Doppler velocimetry measurements in horses through Doppler ultrasonography and to correlate changes in these measurements with possible risk factors for laminitis and / or other foot diseases. The project was approved for its execution through protocol N°. 3769100419 granted by the UFPB Ethics Committee. The analyzes were performed at Horse Training Centers and at the Veterinary Hospital - CCA / UFPB, in Areia, Paraíba State. Fourteen animals were used, which were trichotomized at the time of the third metacarpal bone, medial face of both thoracic limbs. The sonoscape S2V ultrasound device with color Doppler coupled to a 7 MHz linear probe was placed at the height of the median artery, in which B was measured. Then, the color Doppler mode was used to determine the doppler velocimeter measurements. Thus, with a 95% confidence interval in mode B 0,509 ± 0,133 of the median artery diameter was determined and in Doppler mode 2,198 ± 1,451 of the pulsatility index and 0,734 ± 0,906 of the resistivity index (non-parametric data). as reference values for normality of median artery vascularization. It is concluded that more studies need to be developed to attest to the reliability of these values. Moreover, they may help in the early diagnosis, improving the prognosis of these animals prone to laminitis and other foot diseases.
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Rufino, Andressa Kelly Barbosa, Renan Paraguassu de Sá Rodrigues, Andrezza Braga Soares Da Silva, Maria Angélica Parentes da Silva Barbosa, Kássio Vieira Macedo, Francisco das Chagas Araújo Sousa, Daniele Clímaco Marques, Amilton Paulo Raposo Costa et Flávio Ribeiro Alves. « Presumed Normal Hemodynamic Values of the Arteries in the Final Third Period of Gestation in Bitches ». Acta Scientiae Veterinariae 50 (13 janvier 2022). http://dx.doi.org/10.22456/1679-9216.119012.
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Background: Doppler ultrasonography enables the investigation of vascular blood flow indexes in gestational assessment, being able to detect vascular resistances that can affect fetal and maternal circulation, such as cases of placental insufficiency, associated with fetal cerebral oxygenation deficit and fetal distress. The study aims to assume hemodynamically normal values in the final third of gestation in bitches, of the umbilical, uteroplacental, middle cerebral and internal carotid arteries, correlating the obtained Doppler velocimetric indexes, for the assessment of the feto-placental circulation, and prediction of fetal viability indexes, fetal centralization and probable date of delivery.Materials, Methods & Results: Thirty healthy bitches were examined in the final third of gestation (40-60 days). These were evaluated by Doppler ultrasonography at 2 times (T): T1: between 40-50 days; T2: between 51-60 of gestation. At each time point, the peak systolic velocities (PSV) and end-diastolic velocities (EDV) used to obtain the pulsatility (IP) and resistivity (IR) indexes of the umbilical, uteroplacental, middle cerebral and internal carotid arteries of fetuses were evaluated. Also, the systole/diastole (S/D) ratio of these vessels was evaluated. The data obtained were subjected to analysis of variance and Tukey test, using a P value equal to 5%. A significant difference was observed between velocities and Doppler velocimetric indexes between the 2 phases of the gestational final third in all studied vessels. There was an increase in the values of PSV and EDV and a decrease in the indexes, as the probable date of delivery approached. The analysis of the umbilical cord IR showed an increase from P1 to P2 (P < 0.05), while the IP decreased at the same time. For all studied variables there was a statistically significant difference (P < 0.05). In the uteroplacental artery, similarly to the umbilical artery, the PSV and EDV values showed an increase between P1 and P2, while the S/D ratio decreased up to 60 days of gestation (P2). The IR and IP of these vessels decreased during the study interval in pregnant bitches. The studied variables showed a statistically significant difference when analyzed comparatively between P1 and P2 (P < 0.05). As for the middle cerebral artery and internal carotid artery, the PSV and EDV values increased until the end of pregnancy. Likewise, the Doppler velocimetric values and the S/D ratio decreased until the end of pregnancy (P2).Discussion: The hemodynamic values obtained for the umbilical artery and uterine artery were significantly different between 40 and 50 days of gestation (P1) and 50 and 60 days of gestation (P2), with a decrease in vascular resistance and an increase in velocities. It can be related to a greater association of maternal-fetal blood perfusion, due to the increased demand for the development of the fetus. The Middle Cerebral Artery (MCA) also showed changes between P1 and P2, with an increase in PSV and EDV in the final third of pregnancy, and the S/D ratio was reduced, differing significantly between P1 and P2. The systolic (PSV) and diastolic (EDV) flow velocities of the internal carotid artery increased progressively, while the IR, IP and the S/D ratio decreased, between the evaluated periods (P1 and P2), providing greater flow in canine fetuses, maintaining normal heart rate, indicating positive fetal viability. Keywords: Doppler, gestational ultrasound, bitches, fetal circulation, umbilical artery, internal carotid, fetal middle cerebral artery.
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Chèze, Jérôme, Christophe Maron, Diane Rivet, Fabrice Peix, Didier Brunel, Xavier Martin et Bertrand Delouis. « METEOR : Online Seismic Metadata Builder ». Seismological Research Letters, 23 décembre 2020. http://dx.doi.org/10.1785/0220200217.
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Abstract METEOR is an online tool dedicated to the generation of instrumental responses for seismological stations. This tool builds the complete response of the acquisition chain, while keeping the number of fields to be filled in very reduced. METEOR queries a very rich response databank, designed for the management of the French broadband seismological network (RESIF) and for many research projects involving velocimetric and accelerometric sensors over the last 20 yr. This tool is not intended to allow the management of metadata of an entire network, but to quickly build the instrumental responses of temporary stations. Information about the measuring instruments and their settings can be entered directly in the field, or later, back in the office. Instrument responses can be produced in the International Federation of Digital Seismograph Networks Station Extended Markup Language format (FDSN StationXML) and the metadata-only form of the Standard for Exchange of Earthquake Data (dataless SEED). METEOR is publicly available (see Data and Resources).
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Gupta, Sumeet, Michaela Soellinger, Peter Boesiger, Dimos Poulikakos et Vartan Kurtcuoglu. « Three-Dimensional Computational Modeling of Subject-Specific Cerebrospinal Fluid Flow in the Subarachnoid Space ». Journal of Biomechanical Engineering 131, no 2 (10 décembre 2008). http://dx.doi.org/10.1115/1.3005171.
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This study aims at investigating three-dimensional subject-specific cerebrospinal fluid (CSF) dynamics in the inferior cranial space, the superior spinal subarachnoid space (SAS), and the fourth cerebral ventricle using a combination of a finite-volume computational fluid dynamics (CFD) approach and magnetic resonance imaging (MRI) experiments. An anatomically accurate 3D model of the entire SAS of a healthy volunteer was reconstructed from high resolution T2 weighted MRI data. Subject-specific pulsatile velocity boundary conditions were imposed at planes in the pontine cistern, cerebellomedullary cistern, and in the spinal subarachnoid space. Velocimetric MRI was used to measure the velocity field at these boundaries. A constant pressure boundary condition was imposed at the interface between the aqueduct of Sylvius and the fourth ventricle. The morphology of the SAS with its complex trabecula structures was taken into account through a novel porous media model with anisotropic permeability. The governing equations were solved using finite-volume CFD. We observed a total pressure variation from −42Pato40Pa within one cardiac cycle in the investigated domain. Maximum CSF velocities of about 15cm∕s occurred in the inferior section of the aqueduct, 14cm∕s in the left foramen of Luschka, and 9cm∕s in the foramen of Magendie. Flow velocities in the right foramen of Luschka were found to be significantly lower than in the left, indicating three-dimensional brain asymmetries. The flow in the cerebellomedullary cistern was found to be relatively diffusive with a peak Reynolds number (Re)=72, while the flow in the pontine cistern was primarily convective with a peak Re=386. The net volumetric flow rate in the spinal canal was found to be negligible despite CSF oscillation with substantial amplitude with a maximum volumetric flow rate of 109ml∕min. The observed transient flow patterns indicate a compliant behavior of the cranial subarachnoid space. Still, the estimated deformations were small owing to the large parenchymal surface. We have integrated anatomic and velocimetric MRI data with computational fluid dynamics incorporating the porous SAS morphology for the subject-specific reconstruction of cerebrospinal fluid flow in the subarachnoid space. This model can be used as a basis for the development of computational tools, e.g., for the optimization of intrathecal drug delivery and computer-aided evaluation of cerebral pathologies such as syrinx development in syringomelia.
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Shaw, Cody L., Deborah J. Gulledge, Ryan Swindle, Stuart M. Jefferies et Neil Murphy. « PMODE I : Design and Development of an Observatory for Characterizing Giant Planet Atmospheres and Interiors ». Frontiers in Astronomy and Space Sciences 9 (24 mars 2022). http://dx.doi.org/10.3389/fspas.2022.768452.
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The giant planets of our Solar System are exotic laboratories, enshrouding keys which can be used to decipher planetary formation mysteries beneath their cloudy veils. Seismology provides a direct approach to probe beneath the visible cloud decks, and has long been considered a desirable and effective way to reveal the interior structure. To peer beneath the striking belts and zones of Jupiter and to complement previous measurements—both Doppler and gravimetric—we have designed and constructed a novel instrument suite. This set of instruments is called PMODE—the Planetary Multilevel Oscillations and Dynamics Experiment, and includes a Doppler imager to measure small shifts of the Jovian cloud decks; these velocimetric measurements contain information related to Jupiter’s internal global oscillations and atmospheric dynamics. We present a detailed description of this instrument suite, along with data reduction techniques and preliminary results (as instrumental validation) from a 24-day observational campaign using PMODE on the AEOS 3.6 m telescope atop Mount Haleakalā, Maui, HI during the summer of 2020, including a precise Doppler measurement of the Jovian zonal wind profile. Our dataset provides high sensitivity Doppler imaging measurements of Jupiter, and our independent detection of the well-studied zonal wind profile shows structural similarities to cloud-tracking measurements, demonstrating that our dataset may hold the potential to place future constraints on amplitudes and possible excitation mechanisms for the global modes of Jupiter.
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Holmlund, P., S. Qvarlander, J. Malm et A. Eklund. « Can pulsatile CSF flow across the cerebral aqueduct cause ventriculomegaly ? A prospective study of patients with communicating hydrocephalus ». Fluids and Barriers of the CNS 16, no 1 (décembre 2019). http://dx.doi.org/10.1186/s12987-019-0159-0.
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Abstract Background Communicating hydrocephalus is a disease where the cerebral ventricles are enlarged. It is characterized by the absence of detectable cerebrospinal fluid (CSF) outflow obstructions and often with increased CSF pulsatility measured in the cerebral aqueduct (CA). We hypothesize that the cardiac-related pulsatile flow over the CA, with fast systolic outflow and slow diastolic inflow, can generate net pressure effects that could source the ventriculomegaly in these patients. This would require a non-zero cardiac cycle averaged net pressure difference (ΔPnet) over the CA, with higher average pressure in the lateral and third ventricles. Methods We tested the hypothesis by calculating ΔPnet across the CA using computational fluid dynamics based on prospectively collected high-resolution structural (FIESTA-C, resolution 0.39 × 0.39 × 0.3 mm3) and velocimetric (2D-PCMRI, in-plane resolution 0.35 × 0.35 mm2) MRI-data from 30 patients investigated for communicating hydrocephalus. Results The ΔPnet due to CSF pulsations was non-zero for the study group (p = 0.03) with a magnitude of 0.2 ± 0.4 Pa (0.001 ± 0.003 mmHg), with higher pressure in the third ventricle. The maximum pressure difference over the cardiac cycle ΔPmax was 20.3 ± 11.8 Pa and occurred during systole. A generalized linear model verified an association between ΔPnet and CA cross-sectional area (p = 0.01) and flow asymmetry, described by the ratio of maximum inflow/outflow (p = 0.04), but not for aqueductal stroke volume (p = 0.35). Conclusions The results supported the hypothesis with respect to the direction of ΔPnet, although the magnitude was low. Thus, although the pulsations may generate a pressure difference across the CA it is likely too small to explain the ventriculomegaly in communicating hydrocephalus.