Study made of large amplitude fuel sloshing

Study of resonant oscillations of an ideal fluid in a cylindrical tank is used to obtain a better understanding of fuel sloshing in large liquid booster. More realistic structural design criteria may be formulated when the dynamic response of the liquid in a cylindrical tank can be predicted analytically

Local quasiparticle density of states of superconducting SmFeAsO1−x1-xFxx single crystals: Evidence for spin-mediated pairing

We probe the local quasiparticles density-of-states in micron-sized SmFeAsO$_{1-x}$F$_{x}$ single-crystals by means of Scanning Tunnelling Spectroscopy. Spectral features resemble those of cuprates, particularly a dip-hump-like structure developed at energies larger than the gap that can be ascribed to the coupling of quasiparticles to a collective mode, quite likely a resonant spin mode. The energy of the collective mode revealed in our study decreases when the pairing strength increases. Our findings support spin-fluctuation-mediated pairing in pnictides.Comment: 11 pages, 4 figure

A novel MLSD receiver architecture for nonlinear channels

A new architecture for maximum likelihood sequence detec- tion (MLSD) in nonlinear dispersive channels (NLCs) is presented, and its robustness to inaccurate channel knowledge is analyzed. This architecture is developed by considering a novel orthogonal representation of the NLC, which is exploited to develop a front-end capable of obtaining uncorrelated symbol rate samples, representing a sufficient statistic for information decoding. This front-end is a special form of space-time whitened matched filter (ST-WMF), and the MLSD obtained by using this front-end (ST-WMF-MLSD) requires simple branch metrics due to the signal whitening. The ST-WMF also allows for space-time compression of the equivalent channel, which is exploited for further complexity reduction of the ST-WMF-MLSD. Simulation results show the good trade-off in performance and complexity obtained with the ST-WMF- MLSD, even in the presence of inaccurate channel knowledge.Sociedad Argentina de Informática e Investigación Operativa (SADIO

A novel MLSD receiver architecture for nonlinear channels

A new architecture for maximum likelihood sequence detec- tion (MLSD) in nonlinear dispersive channels (NLCs) is presented, and its robustness to inaccurate channel knowledge is analyzed. This architecture is developed by considering a novel orthogonal representation of the NLC, which is exploited to develop a front-end capable of obtaining uncorrelated symbol rate samples, representing a sufficient statistic for information decoding. This front-end is a special form of space-time whitened matched filter (ST-WMF), and the MLSD obtained by using this front-end (ST-WMF-MLSD) requires simple branch metrics due to the signal whitening. The ST-WMF also allows for space-time compression of the equivalent channel, which is exploited for further complexity reduction of the ST-WMF-MLSD. Simulation results show the good trade-off in performance and complexity obtained with the ST-WMF- MLSD, even in the presence of inaccurate channel knowledge.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Controlling Fast Chaos in Delay Dynamical Systems

We introduce a novel approach for controlling fast chaos in time-delay dynamical systems and use it to control a chaotic photonic device with a characteristic time scale of ~12 ns. Our approach is a prescription for how to implement existing chaos control algorithms in a way that exploits the system's inherent time-delay and allows control even in the presence of substantial control-loop latency (the finite time it takes signals to propagate through the components in the controller). This research paves the way for applications exploiting fast control of chaos, such as chaos-based communication schemes and stabilizing the behavior of ultrafast lasers.Comment: 4 pages, 4 figures, to be published in Physical Review Letter

Do not disturb the family: roles of colony size and human disturbance in the genetic structure of lesser kestrel

Dispersal and philopatry are fundamental processes influencing the genetic structure and persistence of populations and might be affected by isolation and habitat perturbation. Habitat degradation induced by human activities could have detrimental consequences on genetic structure of populations. Therefore, it is crucial to understand the role of human impacts in promoting or disrupting genetic structure. Here, we conducted a genetic analysis using 12 polymorphic microsatellite markers of 70 lesser kestrels (Falco naumanni) from 10 breeding colonies of two subpopulations in Sicily (southern Italy). Genetic differentiation between the two subpopulations was negligible, and linear distances played no role in the level of genetic relatedness recorded in the two sites. Linear distances between nests also resulted in no effects on the relatedness recorded within and between colonies in the largest subpopulation. Clusters of more versus less related individuals resulted when the two-dimensional positions of colonies (i.e., latitude and longitude) were tested as predictors of genetic proximity instead of linear distances. Specifically, analyses of colony features showed colony size and human disturbance as factors negatively affecting the relatedness among chicks from different nests. Regardless of colony size, less-related individuals were born in colonies located in the core of the agricultural plain, where we quantified a higher level of human disturbance. In contrast, more related individuals were in colonies that existed in the marginal, less disturbed, agricultural area. Given the high philopatry of this species, our results are consistent with disruption of colony fidelity related to intensification of agricultural practices. We discuss the possible implications of long-term effects of genetic variability in small and disturbed colonies on fitness and population viability

Imaging the essential role of spin-fluctuations in high-Tc superconductivity

We have used scanning tunneling spectroscopy to investigate short-length electronic correlations in three-layer Bi2Sr2Ca2Cu3O(10+d) (Bi-2223). We show that the superconducting gap and the energy Omega_dip, defined as the difference between the dip minimum and the gap, are both modulated in space following the lattice superstructure, and are locally anti-correlated. Based on fits of our data to a microscopic strong-coupling model we show that Omega_dip is an accurate measure of the collective mode energy in Bi-2223. We conclude that the collective mode responsible for the dip is a local excitation with a doping dependent energy, and is most likely the (pi,pi) spin resonance.Comment: 4 pages, 4 figure

Singularity of the Vortex Density of States in d-wave Superconductors

In d-wave superconductors, the electronic density of states (DOS) induced by a vortex exhibits 1/|E| divergency at low energies. It is the result of gap nodes in the excitations spectrum outside the vortex core. The heat capacity in two regimes, (T/T_c)^2 >> B/B_{c2} and (T/T_c)^2 << B/B_{c2}, is discussed.Comment: LaTeX file, 8 pages, no figures, submitted to JETP Letter

Article ultrasound-guided funicular block: Ropivacaine injection into the tissue around the spermatic cord to improve analgesia during orchiectomy in dogs

Orchiectomy is a common surgical procedure performed on small animals, and it requires postoperative pain management despite its relative simplicity. This study aimed to evaluate the hemodynamic stability, intraoperative administration of additional hypnotic and/or analgesic drugs, and postoperative pain scores following the combination of ultrasound-guided injection of ropiva-caine hydrochloride into the spermatic cord and infiltration by the same anaesthetic of the incisional prescrotal line (ROP) or general anaesthesia. Dogs in the ROP group showed greater intraoperative hemodynamic stability and lower pain scores than the control group. The locoregional approach used in this study proved effective in minimising the responses to the surgical stimulus and ensured ade-quate analgesia intra-and postoperatively. This method, called ultrasound-guided funicular block, allows orchiectomy to be performed under deep sedation without general anaesthesia

Roadmap for stroke: Challenging the role of the neuronal extracellular matrix

Stroke is a major challenge in modern medicine and understanding the role of the neuronal extracellular matrix (NECM) in its pathophysiology is fundamental for promoting brain repair. Currently, stroke research is focused on the neurovascular unit (NVU). Impairment of the NVU leads to neuronal loss through post-ischemic and reperfusion injuries, as well as coagulatory and inflammatory processes. The ictal core is produced in a few minutes by the high metabolic demand of the central nervous system. Uncontrolled or prolonged inflammatory response is characterized by leukocyte infiltration of the injured site that is limited by astroglial reaction. The metabolic failure reshapes the NECM through matrix metalloproteinases (MMPs) and novel deposition of structural proteins continues within months of the acute event. These maladaptive reparative processes are responsible for the neurological clinical phenotype. In this review, we aim to provide a systems biology approach to stroke pathophysiology, relating the injury to the NVU with the pervasive metabolic failure, inflammatory response and modifications of the NECM. The available data will be used to build a protein–protein interaction (PPI) map starting with 38 proteins involved in stroke pathophysiology, taking into account the timeline of damage and the co-expression scores of their RNA patterns The application of the proposed network could lead to a more accurate design of translational experiments aiming at improving both the therapy and the rehabilitation processes