Guiding properties of a non-isothermal atmosphere for acoustic-gravity waves

The propagation of pressure waves in a stratified, non-isothermal atmosphere is studied in the linear approximation. It is found that acoustic and acoustic-gravity waves can be horizontally guided by the effect of the Earth’s thermocline alone, under very mild conditions on the temperature gradient steepness. The effect of the Earth’s surface is also studied. Lamb’s modes associated with the rigid surface are, then, identified and their behaviour, as a function of the Earth’s position, is discussed. Finally, dissipation is included, and its effect is derived using a perturbation technique

Intracavity intensity noise suppression in the inverse Compton scattering source BriXSinO exploiting carrier-envelope offset manipulation

We report on a technique that exploits the control of the carrier -envelope offset to suppress the frequency-to-intensity noise conversion in the locking of a mode-locking laser against a high-finesse optical enhancement resonator. A proper combination of the laser carrier-envelope offset and the resonator finesse allows the improvement of the signal-to-noise ratio of the optical intensity trapped into the optical resonator. In this paper, we show the application of this technique in the laser system of the inverse Compton scattering source BriXSinO, currently under development in Milan, Italy, demonstrating the possibility of achieving an intracavity intensity noise reduction of a factor of 20

Linear entropy fails to predict entanglement behavior in low-density fermionic systems

Entanglement is considered a fundamental ingredient for quantum technologies and condensed matter systems are among the good candidates for quantum devices. For bipartite pure states the von Neumann entropy is a proper measure of entanglement, while the linear entropy, associated to the mixedness of the reduced density matrices, is a simpler quantity to be obtained and is considered to be qualitatively equivalent to the von Neumann. Here we investigate both linear and von Neumann entropies for quantifying entanglement in homogeneous, superlattice and disordered Hubbard chains. We find regimes of parameters for which the linear entropy fails in reproducing the qualitative behavior of the von Neumann entropy. This then may lead to incorrect predictions i) of maximum and minimum entanglement states and ii) of quantum phase transitions

Architettura e Realismo. Programma

Il convegno "«Uno spazio reale adeguato»: architettura e realismo", la giornata di studi e mostra "«Il sempre teorizzar nulla rileva...»: nuovo realismo e architettura della città", il convegno "Per una nozione operativa di realismo: espressione critica e impegno civile e la mostra Il realismo nella didattica del progetto: Torino Napoli Milano", uniti sotto il titolo comune di Architettura e realismo sono promossi da un gruppo di lavoro costituito da giovani ricercatori e docenti delle facoltà di Architettura di Torino, Milano e Napoli, a partire dalla avvertita esigenza di aggiornare la riflessione sulla architettura come pratica costruttiva e sulla città come luogo per eccellenza della vita dell'uomo a partire da una analisi critica di quanto si è prodotto negli ultimi decenni. Da un lato grandi architetture spettacolari che rispondono alle logiche del mercato e della comunicazione e, dall'altro - in una sorta di inspiegabile paradosso - la de- regolazione della città diffusa priva di struttura, elementi riconoscibili e spazio pubblico. In entrambi i casi, pur nella loro diversità, si è prodotto un pericoloso distacco della architettura dal suo obiettivo ultimo: conformare lo spazio fisico dei manufatti e della città, del territorio e del paesaggio, per determinare in maniera consistente lo scenario della vita dell'uomo, nella sua dimensione, innanzitutto, collettiv

Design and Optimization of a Pneumatic Clamping System for Direct-Driven Rotary Tables

Modern direct-driven and high-speed rotary tables with torque motor are optimally suited for all handling and assembly applications that require the shortest indexing times and flexible positioning. The following paper is devoted to the study, the design, and the optimization of an innovative table clamping system (brake for accurate positioning) actuated by pneumatic energy, working at a maximum clamping pressure of 6 bar. The challenge for the aforementioned application is related to developing a solution able to provide a maximum tangential torque (with clamping actuated) in the range of thousands of Nm without leveraging the use of high-pressure hydraulic energy. The optimization of the proposed solution is based on the precise calculation of the stresses in order to perform a fatigue assessment and on the elastic deformation of the clamps in order to set the correct tolerances between the mating parts. Eventually, an experimental campaign is carried out in order to tune the numerical model, which is then used to validate the proposed design solution

Marker-Assisted Pyramiding of Blast-Resistance Genes in a japonica Elite Rice Cultivar through Forward and Background Selection

Rice blast, caused by Pyricularia oryzae, is one of the main rice diseases worldwide. The pyramiding of blast-resistance (Pi) genes, coupled to Marker-Assisted BackCrossing (MABC), provides broad-spectrum and potentially durable resistance while limiting the donor genome in the background of an elite cultivar. In this work, MABC coupled to foreground and background selections based on KASP marker assays has been applied to introgress four Pi genes (Piz, Pib, Pita, and Pik) in a renowned japonica Italian rice variety, highly susceptible to blast. Molecular analyses on the backcross (BC) lines highlighted the presence of an additional blast-resistance gene, the Pita-linked Pita2/Ptr gene, therefore increasing the number of blast-resistance introgressed genes to five. The recurrent genome was recovered up to 95.65%. Several lines carrying four (including Pita2) Pi genes with high recovery percentage levels were also obtained. Phenotypic evaluations confirmed the effectiveness of the pyramided lines against multivirulent strains, which also had broad patterns of resistance in comparison to those expected based on the pyramided Pi genes. The developed blast-resistant japonica lines represent useful donors of multiple blast-resistance genes for future rice-breeding programs related to the japonica group

Superconducting RFQs

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