Gaussian approach versus Dolph-Chebyshev synthesis of pencil beams for linear antenna arrays

A very simple and fast method for the synthesis of pencil beams with linear antenna arrays of equally spaced elements is presented. The proposed procedure starts selecting the desired pencil beam as a Gaussian function. This is very convenient for two reasons: first, the continuous line-source distribution that exactly produces the desired pencil beam (i.e. the Fourier transform of it) is in turn a Gaussian function and is immediately calculated. Second, a suitable weighted sampling of this distribution gives the excitations of the array elements in closed form. Two numerical examples reveal the good performances of the proposed approach, also in comparison with the classical method by Dolph-Chebyshev. It is shown that the synthesised array factors well approximate the desired pencil beams in real time, in particular ensuring a very good behaviour in the side lobe regions. Furthermore, the \u2018dynamic range ratio\u2019 of the excitations, defined as the ratio between the maximum and the minimum amplitude of the excitations, is very low and close to unity when the array length is sufficiently small

Electromagnetic field and short-range wake function in a beam pipe of elliptical cross section

Within the ultrarelativistic limit, analytical expressions are found for the high-frequency resistive-wall coupling impedance of an elliptical cross-section vacuum chamber. Subsequently, the corresponding wake functions are derived by performing inverse Fourier transformations numerically. The electromagnetic fields have been developed working out two systems of solutions, namely for the vacuum and for the resistive wall. The constants involved in these systems have been determined by matching boundary conditions at the interface vacuum wall. Several study cases have been considered concerning the aspect ratio of the elliptical cross section and the transverse position of the leading charge in order to exemplify the behavior of the longitudinal and transverse wake functions

Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

Abstract Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted

Design and Field Measurements of a Linear Accelerator Endowed with Single Feed with Movable Short Coupler

Field asymmetries in the rf coupler of accelerating structures degrade the projected beam transverse emittance, especially at low energy. This paper presents an alternative single feed coupler design that reduces the dipolar and the quadrupolar field components by exploiting a movable short circuit placed on the opposite waveguide. The structure has been simulated and optimized with the Ansys HFSS simulation code. RF measurements on an aluminum prototype machined in the "Elettra - Sincrotrone Trieste S.C.p.A.", are here presented. Such results are in good agreement with the simulations

Prima e dopo la letteratura. Il veneziano e il fantasma della grammatica

L'articolo nel suo insieme si coinfronta con la curiosa circostanza per cui una lingua di precoce impiego letterario quale il veneziano abbia conosciuto una deduzione grammaticale soltanto nell'Ottocento e nella sede un poco eccentrica di una privata - e sino a pochi anni fa inedita - sperimentazione ad opera di Daniele Manin. La parte di Drusi, dedicata alla fase antica dell'impiego letterario del veneziano, raccoglie alcune espressioni linguistiche veneziane di non veneziani compresi fra il Trecento (Francesco di Vannozzo) e il Cinquecento (Francesco Sansovino), e ne considera la tecnica imitativa allo scopo di evidenziare alcune costanti idiomatiche che fungevano presso gli alloctoni da etichetta "grammaticale" del veneziano stesso

Glutamate induces autophagy via the two-pore channels in neural cells

NAADP (nicotinic acid adenine dinucleotide phosphate) has been proposed as a second messenger for glutamate in neuronal and glial cells via the activation of the lysosomal Ca2+ channels TPC1 and TPC2. However, the activities of glutamate that are mediated by NAADP remain unclear. In this study, we evaluated the effect of glutamate on autophagy in astrocytes at physiological, non-toxic concentration. We found that glutamate induces autophagy at similar extent as NAADP. By contrast, the NAADP antagonist NED-19 or SiRNA-mediated inhibition of TPC1/2 decreases autophagy induced by glutamate, confirming a role for NAADP in this pathway. The involvement of TPC1/2 in glutamate-induced autophagy was also confirmed in SHSY5Y neuroblastoma cells. Finally, we show that glutamate leads to a NAADP-dependent activation of AMPK, which is required for autophagy induction, while mTOR activity is not affected by this treatment. Taken together, our results indicate that glutamate stimulates autophagy via NAADP/TPC/AMPK axis, providing new insights of how Ca2+ signalling glutamate-mediated can control the cell metabolism in the central nervous system

Fast modularisation and aomic decomposition of ontologies using axiom dependency hypergraphs

In this paper we define the notion of an axiom dependency hypergraph, which explicitly represents how axioms are included into a module by the algorithm for computing locality-based modules. A locality-based module of an ontology corresponds to a set of connected nodes in the hypergraph, and atoms of an ontology to strongly connected components. Collapsing the strongly connected components into single nodes yields a condensed hypergraph that comprises a representation of the atomic decomposition of the ontology. To speed up the condensation of the hypergraph, we first reduce its size by collapsing the strongly connected components of its graph fragment employing a linear time graph algorithm. This approach helps to significantly reduce the time needed for computing the atomic decomposition of an ontology. We provide an experimental evaluation for computing the atomic decomposition of large biomedical ontologies. We also demonstrate a significant improvement in the time needed to extract locality-based modules from an axiom dependency hypergraph and its condensed version

Safety, tolerability and efficacy of intradermal rabies immunization with DebioJect™.

In a single-center study, 66 healthy volunteers aged between 18 and 50years were randomized to be immunized against rabies with three different injection routes: intradermal with DebioJect™ (IDJ), standard intradermal with classical needle (IDS), also called Mantoux method, and intramuscular with classical needle (IM). "Vaccin rabique Pasteur®" and saline solution (NaCl 0.9%) were administered at D0, D7 and D28. Antigen doses for both intradermal routes were 1/5 of the dose for IM. Tolerability, safety and induced immunogenicity of IDJ were compared to IDS and IM routes. Pain was evaluated at needle insertion and at product injection for all vaccination visits. Solicited Adverse Event (SolAE) and local reactogenicity symptoms including pain, redness and pruritus were recorded daily following each vaccination visit. Adverse events (AE) were recorded over the whole duration of the study. Humoral immune response was measured by assessing the rabies virus neutralizing antibody (VNA) titers using Rapid Fluorescent Focus Inhibition Test (RFFIT). Results demonstrated that the DebioJect™ is a safe, reliable and efficient device. Significant decreases of pain at needle insertion and at vaccine injection were reported with IDJ compared to IDS and IM. All local reactogenicity symptoms (pain, redness and pruritus) after injection with either vaccine or saline solution, were similar for IDJ and IDS, except that IDJ injection induced more redness 30min after saline solution. No systemic SolAE was deemed related to DebioJect™ and classical needles. No AE was deemed related to DebioJect™. No Serious Adverse Event (SAE) was reported during the study. At the end of the study all participants were considered immunized against rabies and no significant difference in humoral response was observed between the 3 studied routes

Effect of pre-season training phase on anthropometric, hormonal and fitness parameters in young soccer players

The aims of the study were to investigate 1) the effect of 8 weeks of PSP training on anthropometrics, salivary hormones and fitness parameters in youth soccer players, 2) the correlations between fitness and hormonal parameters, and 3) the impact of the experience of the coach and his methodology of training on these parameters. Weight, height, BMI, pubertal development (PDS), salivary Cortisol (sC), salivary Testosterone (sT), salivary sDHEAS, intermittent tests (VO2max), and countermovement jump test (CMJ) modifications of 35 youth soccer players (age: 14±0 yrs; BMI: 20.8±1.8 k/m2 ) from two Italian clubs (“Lupa Frascati” -LF-; “Albalonga” -AL) were analysed. A significant (p<0.05) time by club effect was observed in sC (F(1,31) = 9.7, ES = 1.13), sT (F(1,31) = 4.2, ES = 0.74), CMJ (F(1,28) = 26.5, ES = 1.94), and VO2max (F(1,28) = 8.5, ES = 1.10). Statistical differences (p<0.05) in weight (F(1,32) = 25.5, ES = 0.11), sC (F(1,31) = 32.1, ES = 1.43), sT/sC ratio (F(1,31) = 10.1, ES = 0.97), sDHEAS/sC ratio (F(1,31) = 6.3, ES = 0.70), and VO2max (F(1,28) = 64.3, ES = 1.74) were found within time factor. Between clubs, differences (p<0.05) in sC (F(1,32) = 8.5, ES = 1.17), sT (F(1,31) = 4.2, ES = 0.74), CMJ (F(1,28) = 26.5, ES = 1.50), and VO2max (F(1,28) = 8.5, ES = 1.10) were found. CMJ was inversely correlated with sDHEAS (r = -0.38) before PSP, while Δ of CMJ showed significant correlations with Δ of sC (r = 0.43) and ΔVO2max was inversely correlated with ΔBMI (r = -0.54) and ΔsC (r = -0.37) in all subjects. Considering each single club, ΔVO2max showed correlations with ΔBMI (r = -0.45) in AL, while ΔCMJ showed correlations with ΔPDS (r = 0.72) in LF club. Since the PSP is often limited training time to simultaneously develop physical, technical and tactical qualities, an efficient method to distribute the training load is important in youth soccer players to increase the performance and to avoid injuries