897 research outputs found
An extended hybrid magnetohydrodynamics gyrokinetic model for numerical simulation of shear Alfv\'en waves in burning plasmas
Adopting the theoretical framework for the generalized fishbonelike
dispersion relation, an extended hybrid magnetohydrodynamics gyrokinetic
simulation model has been derived analytically by taking into account both
thermal ion compressibility and diamagnetic effects in addition to energetic
particle kinetic behaviors. The extended model has been used for implementing
an eXtended version of Hybrid Magnetohydrodynamics Gyrokinetic Code (XHMGC) to
study thermal ion kinetic effects on Alfv\'enic modes driven by energetic
particles, such as kinetic beta induced Alfv\'en eigenmodes in tokamak fusion
plasmas
Elliptic CMB Sky
The ellipticity of the anisotropy spots of the Cosmic Microwave Background
measured by the Wilkinson Microwave Anisotropy Probe (WMAP) has been studied.
We find an average ellipticity of about 2, confirming with a far larger
statistics similar results found first for the COBE-DMR CMB maps, and then for
the BOOMERanG CMB maps. There are no preferred directions for the obliquity of
the anisotropy spots. The average ellipticity is independent of temperature
threshold and is present on scales both smaller and larger than the horizon at
the last scattering. The measured ellipticity characteristics are consistent
with being the effect of geodesics mixing occurring in an hyperbolic Universe,
and can mark the emergence of CMB ellipticity as a new observable constant
describing the Universe. There is no way of simulating this effect. Therefore
we cannot exclude that the observed behavior of the measured ellipticity can
result from a trivial topology in the popular flat -CDM model, or from
a non-trivial topology.Comment: 10 pages, 5 figures, the version to appear in Mod.Phys.Lett.
Severe Hemoperitoneum after Patient Self-Induced Fecal Evacuation
An increasing incidence of rectal injuries following patient self-induced harmful acts, aimed to sexual or laxatives porpouses, is a fact reported in literature (El-Ashaal et al., 2008). We herein report a case of severe hemoperitoneum related to a middle and upper rectal third seromuscolar tear caused by a self-induced fecal evacuation by means of an arrow with a covered cork tip. An urgent intestinal diversion by means of a Hartmann's operation was performed. The clinical case is presented in relation to the literature debate, regarding the issue of primary repair or resection and anastomosis versus fecal diversion for penetrating rectal injuries (Fabian, 2002; Cleary et al., 2006; Office of the Surgeon General, 1943; Busic et al., 2002). In conclusion, the importance of avoiding an anastomotic breakdown in a patient undergoing a hemorrhagic shock is highlighted
Comparison of protein carbonyl (Pco), paraoxonase-1 (pon1) and c-reactive protein (crp) as diagnostic and prognostic markers of septic inflammation in dogs
Reliable diagnostic and prognostic markers of sepsis are lacking, but essential in veterinary medicine. We aimed to assess the accuracy of C-Reactive Protein (CRP), protein carbonyls (PCO) and paraoxonase-1 (PON1) in differentiating dogs with sepsis from those with sterile inflammation and healthy ones, and predict the outcome in septic dogs. These analytes were retrospectively evaluated at admission in 92 dogs classified into healthy, septic and polytraumatized. Groups were compared using the Kruskal–Wallis test, followed by a Mann–Whitney U test to assess differences between survivors and non-survivors. Correlation between analytes was assessed using the Spearman’s test, and their discriminating power was assessed through a Receiver Operating Characteristic (ROC) curve. PON1 and CRP were, respectively, significantly lower and higher in dogs with sepsis compared with polytraumatized and clinically healthy dogs (p < 0.001 for both the analytes), and also in dogs with trauma compared with healthy dogs (p = 0.011 and p = 0.017, respectively). PCO were significantly increased in septic (p < 0.001) and polytraumatized (p < 0.005) as compared with healthy dogs. PON1 and CRP were, respectively, significantly lower and higher in dogs that died compared with survivors (p < 0.001 for both analytes). Ultimately, evaluation of CRP and PON1 at admission seems a reliable support to diagnose sepsis and predict outcomes
Nonlinear dynamics of beta induced Alfv\'en eigenmode driven by energetic particles
Nonlinear saturation of beta induced Alfv\'en eigenmode, driven by slowing
down energetic particles via transit resonance, is investigated by the
nonlinear hybrid magnetohyrodynamic gyro-kinetic code (XHMGC). Saturation is
characterized by frequency chirping and symmetry breaking between co- and
counter-passing particles, which can be understood as the the evidence of
resonance-detuning. The scaling of the saturation amplitude with the growth
rate is also demonstrated to be consistent with radial resonance detuning due
to the radial non-uniformity and mode structure
Isoëtes sabatina (Isoëtaceae, Lycopodiopsida): Taxonomic distinctness and preliminary ecological insights
Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres. Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina. To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species was carried out to describe its genetic distinctness, physical and chemical requirements and companion species. The phylogenetic position of I. sabatina was investigated by applying standard DNA barcoding methods. Simultaneously, during summer 2019, the physical and chemical features of water and sediments of the I. sabatina population and five small Alpine lakes colonized by Isoëtes echinospora – a supposed close relative – were characterized. These data were then compared with the available data on the trophic requirements of the target obligate aquatic Isoëtes, together with Isoëtes lacustris and Isoëtes malinverniana. The present survey confirmed the taxonomic and ecological distinctness of I. sabatina – providing the first evidence of genetic differentiation from I. echinospora. Isoëtes sabatina grows in waters with temperature, conductivity and total alkalinity up to 30°C, 561 μS cm−1 and 3.45 meq L−1, respectively. The edaphic requirements of I. sabatina confirm its outstanding conservation value, and this study offers a basic understanding of how to prevent its extinction. Now, all possible actions must be taken immediately to save this species
Processing ANN Traffic Predictions for RAN Energy Efficiency
The field of networking, like many others, is experiencing a peak of interest in the use of Machine Learning (ML) algorithms. In this paper, we focus on the application of ML tools to resource management in a portion of a Radio Access Network (RAN) and, in particular, to Base Station (BS) activation and deactivation, aiming at reducing energy consumption while providing enough capacity to satisfy the variable traffic demand generated by end users. In order to properly decide on BS (de)activation, traffic predictions are needed, and Artificial Neural Networks (ANN) are used for this purpose. Since critical BS (de)activation decisions are not taken in proximity of minima and maxima of the traffic patterns, high accuracy in the traffic estimation is not required at those times, but only close to the times when a decision is taken. This calls for careful processing of the ANN traffic predictions to increase the probability of correct decision. Numerical performance results in terms of energy saving and traffic lost due to incorrect BS deactivations are obtained by simulating algorithms for traffic predictions processing, using real traffic as input. Results suggest that good performance trade-offs can be achieved even in presence of non-negligible traffic prediction errors, if these forecasts are properly processed
Enabling multipath optical routing with hybrid differential delay compensation
Historically, Internet traffic has been routed over the shortest path: that was convenient for best-effort data traffic, but it is not always suitable for today’s scenario where applications can require bandwidth higher than what is available in a single link, even when provided by an optical wavelength-channel. Multi-path (MP) routing is a network functionality that provides more capacity, reduces the probability of link congestion and increases the availability of the transport service.
This paper elaborates on techniques to mitigate the differential delay in all optical networks, recognized as the main problem of multi-path (MP) routing. This work shows how hybrid differential delay compensation (H-DDC) can greatly reduce the use of expensive reconstruction buffers in all optical networks implementing MP optical routing. A novel mixed integer linear programming formulation is proposed for the novel wavelength + H-DDC assignment problem: distributed fiber delay lines (FDL)s combined with electronic reconstruction buffers collocated at optical regeneration points. Numerical results based on commercially available (and rack mountable) FDLs demonstrate the effectiveness of H-DDC in medium size transport networks
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