Pre-Big Bang Scenario on Self-T-Dual Bouncing Branes

We consider a new class of 5-dimensional dilatonic actions which are invariant under T-duality transformations along three compact coordinates, provided that an appropriate potential is chosen. We show that the invariance remains when we add a boundary term corresponding to a moving 3-brane, and we study the effects of the T-duality symmetry on the brane cosmological equations. We find that T-duality transformations in the bulk induce scale factor duality on the brane, together with a change of sign of the pressure of the brane cosmological matter. However, in a remarkable analogy with the Pre-Big Bang scenario, the cosmological equations are unchanged. Finally, we propose a model where the dual phases are connected through a scattering of the brane induced by an effective potential. We show how this model can realise a smooth, non-singular transition between a pre-Big Bang superinflationary Universe and a post-Big Bang accelerating Universe.Comment: 18 pages, minor typos corrected, Sec. 2 expanded with more details on the self-T-dual background, Sec.4 and 5 revised accordingly. Version to appear on JCA

Self-T-Dual Brane Cosmology and the Cosmological Constant Problem

We consider a codimension-one brane embedded in a gravity-dilaton bulk action, whose symmetries are compatible with T-duality along the space-like directions parallel to the brane, and the bulk time-like direction. The equations of motions in the string frame allow for a smooth background obtained by the union of two symmetric patches of AdS space. The Poincar\'{e} invariance of the solution appears to hold independently of the value of the brane vacuum energy, through a self-tuning property of the dilaton ground state. Moreover, the effective cosmology displays a bounce, at which the scale factor does not shrink to zero. Finally, by exploiting the T-duality symmetry, we show how to construct an ever-expanding Universe, along the lines of the Pre-Big Bang scenario.Comment: Minor corrections, comments & references added. Accepted for publicatio

Nootropics use in the workplace. Psychiatric and ethical aftermath towards the new frontier of bioengineering

OBJECTIVE: The authors have sought to expound upon and shed a light on the rise of nootropics, which have gradually taken on a more and more relevant role in workplaces and academic settings. MATERIALS AND METHODS: Multidisciplinary databases have been delved into by entering the following keys: "nootropics", "cognitive enhancement", "workplace", "productivity", "ethics", "bioengineering". In addition, a broad-ranging search has been undertaken on institutional websites in order to identify relevant analysis and recommendations issued by international institutions and agencies. Papers and reports have been independently pored over by each author. This search strategy has led to the identification of 988 sources but only 64 were considered appropriate for the purposes of the paper after being selected by at least 3 of the authors, independently. RESULTS: The notion of an artificially enhanced work performance - carried out by the 'superworker' - is particularly noteworthy and resonates with the conception of contemporary work on so many different levels: the rising need and demands for higher degrees of flexibility and productivity on the job, the implications of a '24/7' society, where more and more services are available at any time, the ever greater emphasis on entrepreneurial spirit, individual self-reliance and self-improvement, and last but not least, the impact of an ageing society on economic standards and performance. CONCLUSIONS: Moreover, it is worth mentioning that human enhancement technologies will predictably and increasingly go hand in hand with gene editing, bioengineering, cybernetics and nanotechnology. Applications are virtually boundless, and may ultimately affect all human traits (physical strength, endurance, vision, intelligence and even personality and mood)

Cytinus under the microscope: Disclosing the secrets of a parasitic plant

Well over 1% of all flowering plants are parasites, obtaining all or part of the nutrients they need from other plants. Among this extremely heterogeneous assemblage, the Cytinaceae form a small group of holoparasites, with Cytinus as the main representative genus. Despite the small number of known species and the fact that it doesn’t attack crops or plants of economic importance, Cytinus is paradigmatic among parasitic plants. Recent research has indeed disclosed many aspects of host–parasite interactions and reproductive biology, the latter displaying a vast array of adaptive traits to lure a range of animal pollinators. Furthermore, analysis of biological activities of extracts of the most common species of Cytinus has provided evidence that this plant could be a valuable source of compounds with high potential in key applicative areas, namely food production (nutraceuticals) and the development of antimicrobial therapeutics. This article offers a complete overview of our current knowledge of Cytinus

POtenzialità della tecnica EIS per il rilievo del degrado delle barriere termiche sottoposte a prove di ossidazione ciclica

reserved3Questo lavoro è dedicato allo studio dell’evoluzione dei rivestimenti tipici delle parti calde delle turbine a gas, costituiti da uno strato metallico e da uno ceramico di zirconia parzialmente stabilizzata con ittria, con funzione di barriera termica. Vengono dapprima mostrati i risultati di una campagna sperimentale svolta su campioni invecchiati in prove di ossidazione ciclica a due diverse temperature e sottoposti ad analisi metallografiche per individuare i meccanismi di degrado indotti dall’esposizione alle elevate temperature e dall’azione di ripetuti cicli termici. Viene poi presa in esame la possibilità di applicare una tecnica di controllo non distruttivo (la spettroscopia d’impedenza elettrochimica) per rilevare il grado crescente di danneggiamento. La variazione degli spettri d’impedenza ottenuti ha confermato la sensibilità della tecnica allo spessore dello strato ceramico, alle sue caratteristiche (porosità e microcriccatura) e alla formazione dello strato di ossido all’interfaccia metallo/ceramico. I risultati ottenuti vengono discussi alla luce delle analisi metallografiche quantitative e delle informazioni reperibili in letteratura. Si suggeriscono infine alcune linee di ulteriore sviluppo.A. Lapina; M. Bestetti; C. RinaldiA., Lapina; Bestetti, Massimiliano; C., Rinald

Critical thermodynamics of the two-dimensional +/-J Ising spin glass

We compute the exact partition function of 2d Ising spin glasses with binary couplings. In these systems, the ground state is highly degenerate and is separated from the first excited state by a gap of size 4J. Nevertheless, we find that the low temperature specific heat density scales as exp(-2J/T), corresponding to an ``effective'' gap of size 2J; in addition, an associated cross-over length scale grows as exp(J/T). We justify these scalings via the degeneracy of the low-lying excitations and by the way low energy domain walls proliferate in this model

From art to astrophysics: how art inspires science communication. A show for planetariums to convey astronomical concepts throughout images, dialogue and art exhibition.

The process which gives life to artworks because painters are inspired by the charm of the Sky is a well-known process. Beauty and mystery of Cosmos have always given mankind, and still give, a lot of masterpieces, from the Halley comet painted by Giotto in the Scrovegni Chapel to the Starry Nights by Vincent Van Gogh. But, what to say about the opposite process? How could art inspire science? In many ways but we propose here one in a format appropriate for science communication. We start from some paintings of Alessandro Rinaldi, an Italian quoted artist present at 54th Biennale International Art Exhibition of Venice. Focusing our attention on few Rinaldi paintings representing some cosmic scenes, such as starry skies, constellations, moons, we will perform a dialogue between Science and Art, played by two women. The dialogue will be written assembling skills in astrophysics, science communication, screenwriting and art. Final product will be a drama performed in a particular theatre, built primarily for educational and entertaining shows about astronomy and the night sky: a planetarium. Public will be involved in an immersive show of artistic and astronomical images, and will listen to the two characters, Lady A and Lady S, discussing both artistic and scientific aspects of each painting: from the raw material used for painting to the real knowledge of represented celestial objects. Few, selected and correct astronomical notions will be conveyed in a new, funny and attractive way also for people not quite interested in science. The proposed format could be regarded as new for science outreach, where Astronomy could be replaced with Natural and Environmental Sciences, while dialogues around scientific issues could be performed inside planetariums as well on other stages. But there is more: well also tell public that Science doesn’t make Art loose her charm and beauty, rather she makes her stronger because mindful of her potential; Art doesn’t make science loose her strictness and reliability, rather she makes her stronger because mindful of her beauty. Public will have the opportunity of seeing real artworks in a exhibit inside the planetarium and filling in a questionnaire before and after the show. In this way changing in scientific notions and the related perception of artworks will be collected in order to have a realistic feedback about the efficiency of our project