156 research outputs found
Robotic approach to the uretero-vesical junction in children: An international multicentric retrospective study
BackgroundRobot-assisted approach to UVJ is getting more and more used in pediatric patients. MethodsIn this retrospective study 26 patients affected by nephro-urological malformations, robotic-surgically treated from 2016 and 2021 at 3 Pediatric Surgery Department were included: 3 (11.5%) primary obstructive megaureter, 2 (7.7%) dysplastic kidneys, 3 (11.5%) duplex collecting system, 18 (69.2%) primary vescico-ureteral reflux (VUR). ResultsMean age at surgery was 6 years old. 22 (84.6%) underwent Lich Gregoire extravesical ureteral reimplantation, 4 (15.4%) total nephroureterectomy. Mean operative time was 230 min. No conversions or intraoperative complications. Median hospital stay was 4 days. There were 4 (15.38%) postoperative complications: 3 (11.54%) persistent VUR and 1 (3.84%) refluxing megaureter. 2 (7.7%) redo-surgery. ConclusionsRobotic Surgery should be considered a safe and effective technique for treatment of UVJ anomalies in children, because it firstly allows surgeons to approach both upper and lower ureteral ends without modifying trocars' placement
An Accurate Third-Order Normal Form Approximation for Power System Nonlinear Analysis
The inclusion of higher-order terms in small-signal (modal) analysis has been an intensive research topic in nonlinear power system analysis. Inclusion of second-order terms with the method of normal forms (MNF) has been well developed and investigated, overcoming the linear conventional small-signal methods used in the power system control and stability analysis. However, application of the MNF has not yet been extended to include third-order terms in a mathematically accurate form to account for nonlinear dynamic stability and dynamic modal interactions. Due to the emergence of larger networks and long transmission line with high impedance, modern grids exhibit predominant nonlinear oscillations and existing tools have to be upgraded to cope with this new situation. In this paper, first, fundamentals of normal form theory along with a review of existing tools based on this theory is presented. Second, a new formulation of MNF based on a third-order transformation of the system’s dynamic approximation is proposed and nonlinear indexes are proposed to make possible to give information on the contribution of nonlinearities to the system stability and on the presence of significant third-order modal interactions. The induced benefits of the proposed method are compared to those afforded by existing MNFs. Finally, the proposed method is applied to a standard test system, the IEEE 2-area 4-generator system, and results given by the conventional linear small signal and existing MNFs are compared to the proposed approach. The applicability of the proposed MNF to larger networks with more complex models has been evaluated on the New England–New York 16-machine 5-area system
A New Fast Track to Nonlinear Modal Analysis of Power System Using Normal Form
The inclusion of higher-order terms in small-signal (modal) analysis augments the information provided by linear analysis and enables better dynamic characteristic studies on the power system. This can be done by applying Normal Form theory to simplify the higher order terms. However, it requires the preliminary expansion of the nonlinear system on the normal mode basis, which is impracticable with standard methods when considering large scale systems. In this paper, we present an efficient numerical method for accelerating those computations, by avoiding the usual Taylor expansion. Our computations are based on prescribing the linear eigenvectors as unknown field in the initial nonlinear system, which leads to solving linear-only equations to obtain the coefficients of the nonlinear modal model. In this way, actual Taylor expansion and associated higher order Hessian matrices are avoided, making the computation of the nonlinear model up to third order and nonlinear modal analysis fast and achievable in a convenient computational time. The proposed method is demonstrated on a single-machine-infinite-bus (SMIB) system and applied to IEEE 3-Machine, IEEE 16- Machine and IEEE 50-Machine systems.This work was supported by TETfund, Nigeri
Cis-regulatory chromatin loops arise before TADs and gene activation, and are independent of cell fate during early Drosophila development
Acquisition of cell fate is thought to rely on the specific interaction of remote cis-regulatory modules (CRMs), for example, enhancers and target promoters. However, the precise interplay between chromatin structure and gene expression is still unclear, particularly within multicellular developing organisms. In the present study, we employ Hi-M, a single-cell spatial genomics approach, to detect CRM–promoter looping interactions within topologically associating domains (TADs) during early Drosophila development. By comparing cis-regulatory loops in alternate cell types, we show that physical proximity does not necessarily instruct transcriptional states. Moreover, multi-way analyses reveal that multiple CRMs spatially coalesce to form hubs. Loops and CRM hubs are established early during development, before the emergence of TADs. Moreover, CRM hubs are formed, in part, via the action of the pioneer transcription factor Zelda and precede transcriptional activation. Our approach provides insight into the role of CRM–promoter interactions in defining transcriptional states, as well as distinct cell types.Fil: Espínola, Sergio Martín. Centre National de la Recherche Scientifique; Francia. Institut National de la Santé et de la Recherche Médicale; Francia. Université de Montpellier. Centre de Biologie Structurale; FranciaFil: Götz, Markus. Université de Montpellier. Centre de Biologie Structurale; Francia. Centre National de la Recherche Scientifique; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Bellec, Maelle. Centre National de la Recherche Scientifique; Francia. Université de Montpellier. Institut de Génétique Moléculaire de Montpellier; Francia. Université de Montpellier. Centre de Biologie Structurale; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Messina, Olivier. Centre National de la Recherche Scientifique; Francia. Université de Montpellier. Institut de Génétique Moléculaire de Montpellier; Francia. Université de Montpellier. Centre de Biologie Structurale; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Fiche, Jean Bernard. Université de Montpellier. Centre de Biologie Structurale; Francia. Centre National de la Recherche Scientifique; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Houbron, Christophe. Université de Montpellier. Centre de Biologie Structurale; Francia. Institut National de la Santé et de la Recherche Médicale; Francia. Centre National de la Recherche Scientifique; FranciaFil: Dejean, Matthieu. Centre National de la Recherche Scientifique; Francia. Université de Montpellier. Institut de Génétique Moléculaire de Montpellier; FranciaFil: Reim, Ingolf. Universitat Erlangen Nuremberg; AlemaniaFil: Cardozo Gizzi, Andres Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional - Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas "Prof. Dr. Alberto C. Taquini". Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional; ArgentinaFil: Lagha, Mounia. Centre National de la Recherche Scientifique; Francia. Université de Montpellier. Institut de Génétique Moléculaire de Montpellier; FranciaFil: Nollmann, Marcelo. Centre National de la Recherche Scientifique; Francia. Institut National de la Santé et de la Recherche Médicale; Francia. Université de Montpellier. Centre de Biologie Structurale; Franci
Evaluation of activated high volume fly ash systems using Na2SO4, lime and quicklime in mortars with high loss on ignition fly ashes
In general, concretes made with blended Portland cement containing high volumes of fly
ash provide an alternative to conventional Portland cement concrete to enable carbon
footprint reduction. This study evaluates the chemical activation of four fly ashes in blends
with Portland cement, by assessing their effects on hydration and compressive strength. In
this study, a sieving process is used to regulate the fly ash composition, which has an
effect in the chemistry and reaction of the mix. The results show the importance of the
amorphous content of the fly ash with respect to achieving a high compressive strength.
The effect of sodium sulfate, added as an activator, is significant in terms of compressive
strength at early age for two of the fly ashes studied; in this case, the parameter used to
correlate with the compressive strength evolution is the amount of portlandite consumed
through pozzolanic reactions. However, sodium sulfate does not have the same effect on
fly ashes with a high amount of Fe2O3, in which portlandite consumption is much lower
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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