Using the transit of Venus to probe the upper planetary atmosphere

The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus during the transit in three different bands with subpixel accuracy: optical (4500A), UV (1600A, 1700A), Extreme UltraViolet (EUV, 171-335A) and soft X-rays (about 10A). We find that, while the Venus optical radius is about 80 km larger than the solid body radius (the expected opacity mainly due to clouds and haze), the radius increases further by more than 70 km in the EUV and soft X-rays. These measurements mark the densest ion layers of Venus' ionosphere, providing information about the column density of CO2 and CO. They are useful for planning missions in situ to estimate the dynamical pressure from the environment, and can be employed as a benchmark case for observations with future missions, such as the ESA Athena, which will be sensitive enough to detect transits of exoplanets in high-energy bands.Comment: 13 pages, 2 figures; published in Nature Communications; the full and copy-edited version is open access at http://www.nature.com/ncomms/2015/150623/ncomms8563/full/ncomms8563.htm

Diventare genitori nel terzo millennio: un'indagine splorativa preliminare per un programma di salute mentale perinatale

In una società che sta cambiando, in cui si sta assistendo a nuove forme di coppia e di famiglia, ci si chiede quanto questi mutamenti possano portare a eventuali cambiamenti psichici nella modalità di generare e di allevare i propri figli nel terzo millennio, per far fronte al pericolo di un indebolimento della identità genitoriale e di disturbi nello sviluppo psichico del bimbo. Nei progetti di prevenzione in ambito perinatale viene individuata pertanto l’esigenza di conoscere come le coppie che intendono generare e diventare genitori affrontino questi processi. E’ necessario che un programma di salute mentale perinatale orientato a promuovere il benessere dei genitori e del bimbo persegua l’obiettivo di sviluppare un progetto di accompagnamento al complesso processo della genitorialità psichica, a partire dal periodo prenatale in cui è possibile già cogliere indicatori di una eventuale vulnerabilità genitoriale. In questo intento abbiamo svolto una indagine preliminare che esplora aspettative, desideri, bisogni e pregresse esperienze che possono caratterizzare la generatività in una prospettiva genitoriale

La dimensione sessuale nel progetto generativo e genitoriale della coppia

In una nostra più ampia recente ricerca sperimentale in corso, stiamo cercando di esplorare le diverse dimensioni che si articolano nei complessi costrutti della progettualità generativa e genitoriale della coppia, attraverso numerose variabili tra le quali la sessualità generativa. La dimensione sessuale viene esplorata attraverso alcune variabili relazionali: il proprio desiderio e quello del partner, la relazione affettiva della coppia, la presenza di armonia piuttosto che tensioni nella coppia, i cambiamenti dei comportamenti relativi alla sessualità, dei propri atteggiamenti e di quelli del partner, l’organizzazione della coppia a seguito dell’evento gravidanza. Sono state coinvolte coppie alla prima generatività e pluripare: nell’ambito del presente contesto vengono evidenziati i primi risultati della indagine su quella che è la dimensione della sessualità generativa della coppia durante la gravidanza

Expected radiation environment and damage for YBCO tapes in compact fusion reactors

We investigate the neutron damage expected in high-temperature superconducting tapes that will be employed in compact fusion reactors. Monte Carlo simulations yield the expected neutron spectrum and fluence at the magnet position, from which the primary knock-on atom energy distributions can be computed for each atomic species comprising the superconductor. This information is then employed to characterize the displacement cascades, in terms of size and morphology, through molecular dynamics simulations. The expected radiation environment is then compared with the neutron spectrum and fluences achievable at the facilities currently available for experimental investigation in order to highlight similarities and differences that could be relevant to the understanding of the radiation hardness of these materials in real fusion conditions. We find that the different neutron spectra result in different damage regimes, the irradiation temperature influences the number of generated defects, and the interaction of the neutrons with the superconductor results in a local increase in temperature. These observations suggest that further experimental investigations are needed in different regimes and that some neutron shielding will be necessary in compact fusion reactors.Funding Agencies|Italian Ministry of Education, University, and Research through Project PRIN HIBiSCUS [201785KWLE]; Programma Operativo Nazionale (PON) Ricerca e Innovazione 2014-2020; Swedish Research Council [2018-05973]; European Cooperation in Science and Technology, COST Action [CA19108]</p

Ultrafast flow of interacting organic polaritons

The strong-coupling of an excitonic transition with an electromagnetic mode results in composite quasi-particles called exciton-polaritons, which have been shown to combine the best properties of their bare components in semiconductor microcavities. However, the physics and applications of polariton flows in organic materials and at room temperature are still unexplored because of the poor photon confinement in such structures. Here we demonstrate that polaritons formed by the hybridization of organic excitons with a Bloch Surface Wave are able to propagate for hundreds of microns showing remarkable third-order nonlinear interactions upon high injection density. These findings pave the way for the studies of organic nonlinear light-matter fluxes and for a technological promising route of dissipation-less on-chip polariton devices working at room temperature.Comment: Improved version with polariton-polariton interactions. 13 pages, 4 figures, supporting 6 pages, 6 figure

First data on microflora of loggerhead sea turtle (Caretta caretta) nests from the coastlines of Sicily

Caretta caretta is threatened by many dangers in the Mediterranean basin, but most are human-related. The purposes of this research were: (i) to investigate microflora in samples from six loggerhead sea turtle nests located on the Sicilian coast and (ii) to understand microbial diversity associated with nests, with particular attention to bacteria and fungi involved in failed hatchings. During the 2016 and 2018 summers, 456 eggs and seven dead hatchling from six nests were collected. We performed bacteriological and mycological analyses on 88 egg samples and seven dead hatchlings, allowing us to isolate: Fusarium spp. (80.6%), Aeromonas hydrophila (55.6%), Aspergillus spp. (27.2%) and Citrobacter freundii (9%). Two Fusarium species were identified by microscopy and were confirmed by PCR and internal transcribed spacer sequencing. Statistical analyses showed significant differences between nests and the presence/absence of microflora, whereas no significant differences were observed between eggs and nests. This is the first report that catalogues microflora from C. caretta nests/eggs in the Mediterranean Sea and provides key information on potential pathogens that may affect hatching success. Moreover, our results suggest the need for wider investigations over extensive areas to identify other microflora, and to better understand hatching failures and mortality related to microbial contamination in this important turtle species

Towards the computation of inclusive decay rates using lattice QCD

We present a non-perturbative computation of inclusive rates of semileptonic decays of heavy mesons from lattice QCD simulations. The calculation is based on the extraction of smeared spectral functions obtained from four-point Euclidean correlation functions computed on configuration ensembles of the JLQCD and ETM collaborations. We compare our results for the inclusive decay rates with analytical predictions from the operator-product expansion, finding a good agreement for the calculation of the inclusive decay rate. This opens the path to the theoretical determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element $V_{cb}$ to a level of precision competitive with the present experimental uncertainty.Comment: 7 pages, 1 figure, to appear in the proceedings of the 51st International Symposium on Multiparticle Dynamics (ISMD

Inclusive semileptonic BB-decays from lattice QCD

We present the lattice QCD calculation of inclusive semileptonic $B_s$-meson decays. We follow a recently proposed method, which is based on the extraction of smeared spectral densities from Euclidean correlation functions and on the numerical reconstruction of the integration kernel relevant for the inclusive decay rate calculation. We compute four-point Euclidean correlation functions using JLQCD and ETM gauge ensembles with unphysically light $b$-quark masses, and apply two different methods for the integration kernel reconstruction. Finally, we show that the lattice results obtained in this work are in good agreement with the analytic predictions of the operator-product-expansion. This opens the path for a future full lattice QCD calculation to be used as theoretical input for the determination of the magnitude of the CKM element $V_{cb}$.Comment: 10 pages, 4 figures, contribution to the 39th International Symposium on Lattice Field Theory, 8th-13th August, 2022, Bonn, Germany. arXiv admin note: substantial text overlap with arXiv:2209.1549

Lattice QCD study of inclusive semileptonic decays of heavy mesons

We present an ab initio study of inclusive semileptonic decays of heavy mesons from lattice QCD. Our approach is based on a recently proposed method, that allows one to address the study of these decays from the analysis of smeared spectral functions extracted from four-point correlators on the lattice, where the smearing is defined in terms of the phase-space integration relevant to the inclusive decays. We present results obtained from gauge-field ensembles from the JLQCD and ETM collaborations, and discuss their relation with theoretical predictions from the operator-product expansion.Comment: 49 pages, 25 figures and 4 table

Regulation of leptin expression by 17beta-estradiol in human placental cells involves membrane associated estrogen receptor alpha

The placenta produces a wide number of molecules that play essential roles in the establishment and maintenance of pregnancy. In this context, leptin has emerged as an important player in reproduction. The synthesis of leptin in normal trophoblastic cells is regulated by different endogenous biochemical agents, but the regulation of placental leptin expression is still poorly understood. We have previously reported that 17β-estradiol (E 2) up-regulates placental leptin expression. To improve the understanding of estrogen receptor mechanisms in regulating leptin gene expression, in the current study we examined the effect of membrane-constrained E 2 conjugate, E-BSA, on leptin expression in human placental cells. We have found that leptin expression was induced by E-BSA both in BeWo cells and human placental explants, suggesting that E 2 also exerts its effects through membrane receptors. Moreover E-BSA rapidly activated different MAPKs and AKT pathways, and these pathways were involved in E 2 induced placental leptin expression. On the other hand we demonstrated the presence of ERα associated to the plasma membrane of BeWo cells. We showed that E 2 genomic and nongenomic actions could be mediated by ERα. Supporting this idea, the downregulation of ERα level through a specific siRNA, decreased E-BSA effects on leptin expression. Taken together, these results provide new evidence of the mechanisms whereby E 2 regulates leptin expression in placenta and support the importance of leptin in placental physiology.Fil: Gambino, Yésica Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Pérez Pérez, Antonio. Hospital Universitario Virgen Macarena; EspañaFil: Dueñas, José L.. Hospital Universitario Virgen Macarena; EspañaFil: Calvo, Juan Carlos. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sánchez Margalet, Víctor. Hospital Universitario Virgen Macarena; EspañaFil: Varone, Cecilia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin