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We consider the 3D simplified Bardina turbulence model with horizontal filtering, fractional dissipation, and the presence of a memory term incorporating hereditary effects. We analyze the regularity properties and the dissipative nature of the considered system and, in our main result, we show the existence of a global exponential attractor in a suitable phase space.

Ileocolic intussusception is a common cause of bowel obstruction. When spontaneous reduction does not occur, non-operative management through enema reduction is necessary. Despite the evidence indicating that sedatives favor success in the reduction, their use is still not a common practice. To determine if midazolam (MDZ) before enema improves the rate of procedure success, we retrospectively reviewed charts of patients admitted to two Italian pediatric emergency departments. Outcome measures were the success rate of the enema, recurrence, and need for surgery. Patients were grouped according to the use of MDZ or not, before hydrostatic reduction attempt. We included 69 and 37 patients in the MDZ and non-MDZ groups, respectively. The two groups did not differ in demographics, clinical characteristics, and ultrasound findings. Intussusception reduction after the first enema attempt occurred in 75% (MDZ group) and 32.4% (non-MDZ group) of patients (P .001); 27.9% (MDZ group) and 77.8% (non-MDZ group) of patients underwent surgery (P .001). Among them, spontaneous reduction of intussusception during the induction of general anesthesia occurred in 31.6% and 42.9% of patients, respectively (P .43). Multivariate logistic regression analysis showed that only MDZ had a positive effect on the result of the enema (OR 7.602, 95%CI 2.669-21.652, P .001).Procedural sedation with MDZ for enema reduction of intussusception can increase the success rate and lead to a better management of patients.• Despite the evidence of the usefulness of sedatives in the reduction of intussusception, their use is still not a common practice.• Midazolam during enema reduction of intussusception can increase the success rate and consequently lead to better management of patients.

Introduction: Surgical management of jejuno-ileal atresia/stenosis (JIA) is shifting to a minimally invasive approach. Our purpose is to evaluate the safety and feasibility of laparoscopy-assisted surgery (LAS) in JIA by comparing outcomes with a control group of open surgery (OS). Methods: A retrospective review of JIA cases was performed. Demographic, surgical, and outcomes data were extracted. LAS cases were compared with OS. Fisher's exact-test for qualitative and Mann-Whitney-test for quantitative values were used. p values

Introduction The uretero-pelvic junction (UPJ) is the most common site of obstruction in the pediatric upper urinary tract, causing hydronephrosis. In our institution, the gold standard approach for hydronephrosis in infants is the One-Trocar- Assisted Pyeloplasty (OTAP). The aim of this study is to evaluate the feasibility of OTAP in terms of efficacy and safety in the first 90 days of life. Methods We retrospectively reviewed all charts and long-term follow-up of 138 infants treated with OTAP; we selected and examined the ones with a defined diagnosis of severe UJPO and, thus, treated in the first 90 days of life: 28 patients. Indica- tions for early surgery were: antero-posterior pelvic diameter (APD) > 20 mm and an obstructive pattern on renography; impaired echotexture and/or relative renal function < 40% had to be associated. Results Out of 23 patients, we witnessed one conversion to open surgery (4.35%) and one recurrence (4.35%) of UPJO. The mean pre-surgery APD was 35.2 mm, while the mean post-surgery APD was 17.32 mm. The mean operative time was 133 min. The mean hospitalization time was 7.71 days. The mean average of follow-up was 46.41 months (minimum 1 year). Conclusions Our experience suggests that OTAP is a valid and feasible technique in terms of safety and efficacy for the early treatment of very young infants affected by UPJO.

Aim of the study: To assess the efficacy of a novel technique (echo-assisted intersphincteric autologous microfragmented adipose tissue injection, also called &ldquo, anal-lipofilling&rdquo, ) in the management of non-responsive fecal incontinence in children born with anorectal malformations (ARMs). Methods: Following ethical committee approval (CHPED-MAR-18-02), anal-lipofilling was proposed to patients with fecal incontinence not responsive to medications or bowel management (bowel enema and/or transanal irrigation automatic systems), then a prospective study was conducted. Anal-lipofilling consisted of three phases: lipoaspiration from the abdominal wall, processing of the lipoaspirate with a Lipogems system and intersphincteric injection of the processed fat tissue via endosonographic assistance. A questionnaire based on Krickenbeck&rsquo, s scale (KS) was administered to the patients to evaluate the clinical outcome. Main Results: Four male patients (three recto-urethral fistula, and one recto-perineal fistula) underwent the anal-lipofilling procedure at a mean age of 13.0 &plusmn, 4.2 yrs. There were no complications during or after the procedure. From an initial assessment of the patients there was an improvement in the bowel function at a median follow up of 6 months, with better scores at KS (100% Soiling grade three pre-treatment vs. 75% grade one post-treatment). Conclusions: Even if our Study is preliminary, echo-assisted anal-lipofilling could be considered as a feasible and safe alternative technique in the management of the fecal incontinence in non-responding ARMs patients. More studies are still necessary to support the validity of the implant of autologous adipose tissue in the anal sphincter as a therapy for fecal incontinence in children born with ARMs.

We consider the Euler–Voigt equations in a smooth bounded domain as an approximation for the 3D Euler equations. We show that the solutions of the Voigt equations are global, do not smooth out the data, and converge to the solutions of the Euler equations. For these reasons they represent a good model, also for computations of turbulent flows.

Introduction The aim of the study was to investigate perinatal outcome of fetuses with hyperechogenic bowel (HB) in relation to gestational age at diagnosis. Materials and Methods This is a retrospective observational study of fetal HB cases from 2002 to 2012. Patients were divided into three groups according to trimester at diagnosis. For each group, data from fetal ultrasound examination, fetal medicine investigations, intrapartum cares, and neonatal outcome were obtained. Results A diagnosis of HB was made in 279 fetuses among them 17 (6%) during the first trimester, 186 (67%) during the second trimester, and 75 (27%) during the third trimester. A significant prevalence of maternal comorbidities was noticed in group 1 (12%: p = 0.02). A chromosomal defect was identified in 13% of the fetuses without difference among the three groups. HB was associated with prenatal infection in 11.5% (n = 32) of the cases, with an equal distribution between groups 2 and 3. Intrauterine growth retardation was noticed in 23% (n = 64) of the cases with a slightly high prevalence in groups 1 (35%). HB was the only ultrasonographic intestinal soft marker in 80% (n = 223) of the fetuses, two-third of them were detected during the first and the second trimesters (p = 0.001). However, HB was associated with bowel dilation in 33% of the cases diagnosed during the third trimester (p = 001). Ultrasonographic extraintestinal anomalies were identified in 30% of the fetuses with a higher prevalence in group 1 (59%). HB resolved spontaneously in 55 (19.7%) cases—without difference among the three groups. In group 1 we recorded a significant prevalence of intrauterine demise (23.5%, p = 0.004). Two hundred twenty-seven (81.3%) pregnancies resulted in live-born neonates; among them gastrointestinal anomalies were noticed in 12.5% with a significant prevalence in group 3 (36%) compared with 6 and 5.4% in groups 1 and 2, respectively (p = 0.001). Extraintestinal anomalies were confirmed in 27% of the cases, whereas postnatal mortality rate was of 7% without differences between the three groups. Conclusion Detection of HB during the first trimester is associated with an increased risk for maternal comorbidities, intrauterine growth retardation, and adverse pregnancy outcome. Moreover, if HB is detected during the second trimester, it is associated with a favorable prognosis. Otherwise, HB detected during the third trimester is associated with a significant risk of gastrointestinal anomaly.

An ultra-dense deployment of small cells is foreseen as the solution to cope with the exponential increase of the data rate demand targeted by the 5th Generation (5G) radio access technology. In this article, we propose an interference-robust air interface built upon the usage of advanced receivers as main interference mitigation technique. Both Interference Rejection Combining (IRC) and Successive Interference Cancellation (SIC) principles are considered. An efficient usage of such receivers is ensured by a proper frame structure design and system assumptions. Different approaches for the rank adaptation are also investigated. Simulation results show that proposed air interface built upon advanced receiver can be a feasible alternative to traditional solutions based on frequency reuse planning. Open issues and further challenges are also addressed.

We consider a Large Eddy Simulation model for a homogeneous incompressible Newtonian fluid in a box space domain with periodic boundary conditions on the lateral boundaries and homogeneous Dirichlet conditions on the top and bottom boundaries, thus simulating a horizontal channel. The model is obtained through the application of an anisotropic horizontal filter, which is known to be less memory consuming from a numerical point of view, but provides less regularity with respect to the standard isotropic one defined as the inverse of the Helmholtz operator. &nbsp It is known that there exists a unique regular weak solution to this model that depends weakly continuously on the initial datum. We show the existence of the global attractor for the semiflow given by the time-shift in the space of paths. We prove the continuity of the horizontal components of the flow under periodicity in all directions and discuss the possibility to introduce a solution semiflow.

We propose a new Large Eddy Simulation (LES) model for the Boussinesq equations. We consider the motion in a three-dimensional domain with solid walls, and in a particular geometrical situation we look for solutions which are periodic in the vertical direction and satisfy homogeneous Dirichlet conditions on the lateral boundary. We are thus modeling a vertical pipe and one main difficulty is that of considering regularizations of the equation which are well behaved also in presence of a boundary. The LES model we consider is then obtained by introducing a vertical filter, which is the natural one for the setting that we are considering. The related interior closure problem is treated in a standard way with a simplified-Bardina deconvolution model. The most technical analytical point is related to the fact that anisotropic filters provide less regularity than the isotropic ones and, in principle, the density term appearing in the Boussinesq equations may behave very differently from the velocity. We are able to define an appropriate notion of regular weak solution, for which we prove existence, uniqueness, and we also show that the energy associated to the model is exactly preserved.

We consider a large eddy simulation model for the 3D Navier–Stokes equations obtained through fractional deconvolution of generic order. The global well-posedness of such a problem is already known. We prove the existence of the global attractor for the solution operator and find estimates for its Hausdorff and fractal dimensions both in terms of the Grashoff number and in terms of the mean dissipation length, with particular attention to the dependence on the fractional and deconvolution parameters. These results can be interpreted as bounds for the number of degrees of freedom of long-time dynamics, thus providing further information on the validity of the model for the simulation of turbulent 3D flows.

We consider two magnetohydrodynamic-α (MHDα) models with kinematic viscosity and magnetic diffusivity for an incompressible fluid in a three-dimensional periodic box (torus). More precisely, we consider the Navier–Stokes-α-MHD and the Modified Leray-α-MHD models. Similar models are useful to study the turbulent behavior of fluids in presence of a magnetic field because of the current impossibility to handle non-regularized systems neither analytically nor via numerical simulations. In both cases, the global existence of the solution and of a global attractor can be shown. We provide an upper bound for the Hausdorff and the fractal dimension of the attractor. This bound can be interpreted in terms of degrees of freedom of the long-time dynamics of the involved system and gives information about the numerical stability of the model. We get the same bound that holds for the Simplified Bardina-MHD model, considered in a previous paper (this result provides, in some sense, an intermediate bound between the number of degrees of freedom for the Simplified Bardina model and the Navier–Stokes-α equation in the nonmagnetic case). However, the Navier–Stokes-α-MHD system is preferable since, in the ideal case, it conserves more quadratic invariants derived from the standard MHD model.

We prove local and global existence results for the Cauchy problem of a regularized magnetohydrodynamic-α model with viscous velocity field and no magnetic diffusivity for an incompressible fluid. Such a model is introduced in analogy with the Navier–Stokes equation to study the turbulent behavior of fluids in presence of a magnetic field. We consider the case of two space dimension.

The finding of a fetal intra-abdominal cyst is relatively common and it can be due to a wide variety of clinical conditions. The aims of this study were to determine the accuracy of the prenatal ultrasound (US) in identifying the etiology of fetal intra-abdominal cysts and to describe the neonatal outcomes.All cases of fetal intra-abdominal cystic lesion referred to our center between 2004 and 2012 were reviewed. Cysts of urinary system origin were excluded. Prenatal and postnatal data were collected. Our cohort was divided into subgroups according to the prenatal suspected origin of the lesion (ovarian, mesenteric, gastro-intestinal and other locations). For each subgroup, sensitivity, specificity, positive predictive value, false-positive rate and accuracy of fetal US were calculated.In total 47 fetuses (10/37 M/F) were identified. The mean gestational age at the time of diagnosis was 33 ± 4.9 weeks. Our cohort comprised of 25 ovarian cysts (10 simplex and 15 complex), 3 GI duplication, 6 mesenteric lesions, 4 meconium pseudocyst and 9 lesions of other origin. Surgery was performed in 38 cases (81%) at birth. The prenatally established diagnosis was exactly concordant with post-natal findings in 34 cases (72.3%). Sensitivity, specificity, positive predictive value and false-positive rate of US were 88.1%, 95.5%, 71% and 5.4%, respectively. Long-term outcome was good in almost 90% of the cases.The etiology of fetal intra-abdominal cysts can be prenatally diagnosed in about 70% cases. Despite the high risk of surgery at birth, the long-term outcome was good in most of the cases.

Time division duplex (TDD) systems offer a substantial amount of freedom to deal with downlink (DL) and uplink (UL) traffic asymmetries. Most TDD-based systems define either multiple static configurations or adaptive approaches to deal with such asymmetries. Our envisioned 5G concept embraces the flexibility brought along by TDD, and allows us to switch the link direction on a slot by slot basis. In this paper we study the interaction of Transmission Control Protocol (TCP) traffic, with a fully flexible UL/DL TDD allocation scheme. We show that flexibility is not only beneficial for exploiting the different instantaneous UL and DL traffic variations, but also performs well with TCP traffic, where the protocol behaviour plays an important role in throughput performance. The advantages of full flexibility compared to fixed static allocations for TCP traffic are reported for both small and large payloads, and for multi-cell scenarios where both DL and UL traffic are present.

We report the case of 22-month-old boy who sustained spontaneous gastric rupture. The patient had an episode of nausea and vomiting after a large meal the day before admission to our emergency ward. Abdominal ultrasonography revealed free and corpuscolate fluid in the abdomen. Abdominal X-ray showed free air in the abdominal cavity, leading to diagnosis of gastrointestinal perforation. Blood examination revealed metabolic acidosis. An emergency laparotomy detected a wide perforation of gastric wall involving fundus and greater curvature. A sleeve gastrectomy was performed with two layers closure of abdominal wall. Idiopathic gastric rupture, beyond neonatal period, is extremely rare in childhood. Early diagnosis and surgery are mandatory to avoid fatal complications.

The purpose of this article is to review ultrasonographic appearance of the most common causes of non-traumatic acute abdominal pain in pediatric patients and to understand the applications and limitations of this technique giving a practical approach showing different clinical cases. A pictorial review of cases was made presenting the most common causes of neonatal and pediatric non-traumatic acute abdominal pain; sonographic features are discussed. Ultrasound in conjunction with Color Doppler imaging is a valuable tool in the evaluation of neonatal and pediatric non-traumatic acute abdominal pain; causes of acute abdomen in children could vary depending on the ages of the children.Lo scopo di questo articolo è stato di revisionare le caratteristiche ecografiche delle più comuni cause di dolore addominale in pazienti pediatrici, per comprendere le applicazioni ed i limiti di questa tecnica con un approccio pratico, presentando diversi casi clinici. Abbiamo revisionato i reperti ecografici delle più comuni cause di dolore addominale acuto pediatrico e neonatale non traumatico, infatti l’ecografia integrata dall’esame Color Doppler è uno strumento importante nella individuazione delle cause, che possono variare in base all’età dei pazienti.

WiFi is the prevalent wireless access technology in local area deployments and is expected to play a major role in a mobile operator’s data offloading strategy. As a result, having simple tools that are able to assess the offloading potential of IEEE 802.11 networks is vital. In this paper, we propose a simple closed-form solution to calculate down- and uplink throughput values per user under full-buffer traffic when small WiFi cells are used to offload macrocells. Extensive measurement campaigns and simulation results demonstrate that there is an excellent quantitative match between analytical model and data despite the simplicity of the former. Finally, in light of our observations we discuss some of the fundamental technological limitations that may have a significant impact on the future of small cells.

We consider the free boundary problem for the plasma-vacuum interface in ideal compressible magnetohydrodynamics (MHD). In the plasma region, the flow is governed by the usual compressible MHD equations, while in the vacuum region we consider the Maxwell system for the electric and the magnetic fields, in order to investigate the well-posedness of the problem, in particular in relation with the electric field in vacuum. At the free interface, driven by the plasma velocity, the total pressure is continuous and the magnetic field on both sides is tangent to the boundary. Under suitable stability conditions satisfied at each point of the plasma-vacuum interface, we derive a basic a priori estimate for solutions to the linearized problem. The proof follows by a suitable secondary symmetrization of the Maxwell equations in vacuum and the energy method. An interesting novelty is represented by the fact that the interface is characteristic with variable multiplicity, so that the problem requires a different number of boundary conditions, depending on the direction of the front velocity (plasma expansion into vacuum or viceversa). To overcome this difficulty, we recast the vacuum equations in terms of a new variable which makes the interface characteristic of constant multiplicity. In particular, we don't assume that plasma expands into vacuum., Comment: arXiv admin note: substantial text overlap with arXiv:1112.3101

We consider the MHD-α model known as double viscous simplified Bardina MHD (SBMHD) on a 3D periodic box (MHD stands for magnetohydrodynamic). This system is a large eddy simulation model useful to approximate the turbulent behavior of an incompressible homogeneous magnetofluid because of the actual impossibility to handle the MHD model neither analytically nor via direct numerical simulation. In a previous paper (joint work with Secchi), the global existence of strong solutions to the SBMHD has been proved as well as the existence of a global attractor of finite fractal dimension. Upper bounds for such dimension are provided both in terms of the modified Grashof number and the dissipation length associated to the mean rate of energy dissipation. In this paper, we commute the same bound in an estimate in terms of the modified Reynolds number R. This result is useful because the classical Kolmogorov theory of turbulence is expressed using the Reynolds number. The global attractor estimate in terms of R is c...

Magnetohydrodynamics (MHD)-α models are regularized systems used to study the turbulent flow of a magnetofluid, because of the impossibility to handle non-regularized models either analitically or numerically. In order to establish the validity of a model as a large eddy simulation model, one needs to test properties related to the number of degrees of freedom of long-time dynamics of the solutions. Preliminary information is provided by estimates concerning the number of determining modes. We consider the MHD–Voight model for an incompressible fluid and find estimates for a number of asymptotically determining modes and modes on global attractor.

We consider radial solutions to the Cauchy problem for a linear wave equation with a small short-range electromagnetic potential (depending on space and time) and zero initial data. We present two dispersive estimates that provide, in particular, an optimal decay rate in time $t^{-1}$ for the solution. Also, we apply these estimates to obtain similar results for the linear massless Dirac equation perturbed by a potential.