Direct dating of mid-crustal shear zones with synkinematic allanite:new in situ U-Th-Pb geochronological approaches applied to the Mont Blanc massif

International audienceDating the timing of motion on crustal shear zones is of tremendous importance for understanding the assembly of orogenic terranes. This objective is achieved in this paper by combining petrological and structural observations with novel developments in in situ U-Th-Pb geochronology of allanite. A greenschist facies shear zone within the Mont Blanc Massif is documented. Allanite is synkinematic and belongs to the mylonitic assemblage. LA-ICP-MS U-Th-Pb isotope analyses of allanite reveal high contents and highly radiogenic isotopic compositions of the common-Pb component. The use of measured Pb-isotope compositions of associated minerals (feldspars and chlorite) is critical for accurate common-Pb correction, and provides a powerful mechanism for linking allanite growth to the metamorphic assemblage. A mean 208Pb/232Th age of 29.44 ± 0.95 Ma is accordingly taken for synkinematic allanite crystallisation under greenschist facies conditions. This age reflects the timing of the Mont Blanc underthrusting below the Penninic Front and highlights the potential of directly dating deformation with allanite

L’arbitrato a modalità irrituale nella riforma dell'arbitrato.

LUISS PhD Thesi

Red Affects Reaction Times and Hit Rates in a 2AFC Classification Task

We measured reaction times and hit rates in a 2AFC orientation discrimination task. Gabor patches at different spatial frequencies and two levels of contrast (0.15 and 0.6) were presented surrounded by red, blue, or grey isoluminant backgrounds.. Results revealed lower accuracy and slower reaction times when the gabors were surrounded by red in comparison to blue or grey backgrounds. We interpret these results as evidence that i) exposure to long-wavelength light interferes with both magnocellular and parvocellular processing; but ii) long-wavelength light causes greater relative inhibition of magnocellular processing. These findings are relevant to the interpretation of studies that use red backgrounds to selectively isolate magnocellular contributions, and may have implications for the interpretation of studies of the effect of red contexts on diverse perceptual and cognitive tasks

A catalogue of nuclear stellar velocity dispersions of nearby galaxies from \u2009H\u3b1 STIS spectra to constrain supermassive black hole masses

We present new measurements for the nuclear stellar velocity dispersion \u3c3* within sub-arcsecond apertures for 28 nearby galaxies. Our data consist of Space Telescope Imaging Spectrograph (STIS) long-slit spectra obtained with the G750M grating centred on the H\u3b1 spectral range. We fit the spectra using a library of single stellar population models and Gaussian emission lines, while constraining in most cases the stellar-population content from an initial fit to G430L STIS spectra. We illustrate how these \u3c3* measurements can be useful for constraining the mass M\u2022 of supermassive black holes (SBHs) by concentrating on the cases of the lenticular galaxies NGC 4435 and NGC 4459. These are characterized by similar ground-based half-light radii stellar velocity dispersion \u3c3e values but remarkably different M\u2022 as obtained from modelling their central ionized-gas kinematics, where NGC 4435 appears to host a significantly undermassive SBH compared to what is expected from the M\u2022 - \u3c3e relation. For both galaxies, we build Jeans axisymmetric dynamical models to match the ground-based stellar kinematics obtained with Spectrographic Areal Unit for Research on Optical Nebulae integral-field spectrograph, including an SBH with M\u2022 value as predicted by the M\u2022 - \u3c3e relation and using high-resolution HST images taken with the Advanced Camera for Surveys to construct the stellar-mass model. By mimicking the HST observing conditions we use such reference models to make a prediction for the nuclear \u3c3* value. Whereas this was found to agree with our nuclear \u3c3* measurement for NGC 4459, for NGC 4435 the observed \u3c3* is remarkably smaller than the predicted one, which further suggests that this galaxy could host an undermassive SBH

Much can change in a year : the Massawan mantis shrimp, Erugosquilla massavensis (Kossmann, 1880) in Sicily, Italy

A flourishing population of the Massawan mantis shrimp, Erugosquilla massavensis, an Erythraean species, is recorded off Sicily, Italy, one year after the very first specimen was collected off the eastern coast of the island. The species is already established as a minor, albeit valuable, fishery resource. Once its population increases, however, it may compete with the native Mediterranean spot-tail mantis shrimp, Squilla mantis. This article presents the results of a joint effort between members of the Museo Civico di Storia Naturale of Comiso and local fishermen to monitor non-indigenous species in Sicilian waters.peer-reviewe

Moonlight on Endymion: in search of 'Arcadian opera', 1688-1721

A paradigm of the earliest operatic endeavors of the Arcadian Academy, the myth of Endymion and Diana inspired librettos by Christina of Sweden and Alessandro Guidi, Francesco de Lemene, and Pietro Metastasio. All of these efforts emerged as reactions to the ‘Baroque,’ yet their dramaturgical and intellectual underpinnings appear to stand in such contrast to each other that the very notion of ‘Arcadian opera’ demands critical revision, at least with respect to its initial stage. The present article will do so by juxtaposing the aforementioned librettos with contemporary tracts by Gian Vincenzo Gravina and Giovanni Antonio Mezzabarba. It will conclude that Arcadia indeed adopted polymorphic traits at first, but that most conflicts dissolved within the towering oeuvre of Pietro Metastasio

Pojava mlađi pjevčine pučinke Luvarus imperialis (Actinopterygii: Perciformes: Luvaridae) u Sicilijskom tjesnacu

Two juveniles Luvarus imperialis, astrodermella stage, 97.4 mm and 90.6 mm in total length, were recorded on September 2016 and August 2017 respectively, the first caught by a bottom trawler off the south-eastern coast of Sicily, Strait of Sicily, Italy, the second found stranded on the beach in the nearby region. Biometrics data of this uncommon species are given and the occurrence of juvenile stages in the Mediterranean area is briefly discussed.Dva primjerka mlađi Luvarus imperialis, (stadij astrodermella) ukupnih dužina 97,4 mm i 90,6 mm, zabilježena su u rujnu 2016., odnosno kolovozu 2017. godine. Prvi primjerak je ulovljen koćom na jugoistočnoj obali Sicilije, Sicilijski tjesnac, Italija. Drugi primjerak je pronađen na plaži u obližnjoj regiji. U ovom radu, autori navode biometrijske podatke ove neobične vrste i ukratko se raspravlja o pojavi mlađih u mediteranskom području

Testing MOND gravity in the shell galaxy NGC 3923

Context. The elliptical galaxy NGC 3923 is surrounded by numerous stellar shells that are concentric arcs centered on the galactic core. They are very likely a result of a minor merger and they consist of stars in nearly radial orbits. For a given potential, the shell radii at a given time after the merger can be calculated and compared to observations. The Modified Newtonian Dynamics (MOND) is a theory that aims to solve the missing mass problem by modifying the laws of classical dynamics in the limit of small accelerations. Hernquist & Quinn(1987) claimed that the shell distribution of NGC 3923 contradicted MOND, but Milgrom(1988) found several substantial insufficiencies in their work. Aims. We test whether the observed shell distribution in NGC 3923 is consistent with MOND using the current observational knowledge of the shell number and positions and of the host galaxy surface brightness profile, which supersede the data available in the 1980s when the last (and negative) tests of MOND viability were performed on NGC 3923. Methods. Using the 3.6 um bandpass image of NGC 3923 from the Spitzer space telescope we construct the mass profile of the galaxy. The evolution of shell radii in MOND is then computed using analytical formulae. We use 27 currently observed shells and allow for their multi-generation formation, unlike the Hernquist & Quinn one-generation model that used the 18 shells known at the time. Results. Our model reproduces the observed shell radii with a maximum deviation of 5% for 25 out of 27 known shells while keeping a reasonable formation scenario. A multi-generation nature of the shell system, resulting from successive passages of the surviving core of the tidally disrupted dwarf galaxy, is one of key ingredients of our scenario supported by the extreme shell radial range. The 25 reproduced shells are interpreted as belonging to three generations.Comment: 8 pages, 3 figures, Accepted for publication in A&

Nuevas estrategias profilácticas y terapéuticas frente a la infección por Streptococcus pneumoniae

Streptococcus pneumoniae es uno de los principales agentes etiológicos causantes de neumonía adquirida en la comunidad y enfermedades más severas, como sepsis y meningitis bacteriana, que afectan principalmente a la población infantil y a los mayores de 65 años (Koedel et al., 2002; van der Poll y Opal, 2009). Se estima que más del 25% de los 57 millones de muertes anuales en todo el mundo, están directamente relacionadas con las enfermedades infecciosas. En concreto, las infecciones respiratorias son responsables de la muerte de 4 millones de personas cada año. Según la organización mundial de la Salud (OMS) la prevalencia de sepsis o neumonía en neonatos, así como de neumonía en niños algo mayores representan el 29% de las 10.6 millones de muertes anuales registradas en niños menores de 5 años (10% y 19%, respectivamente), siendo Streptococcus pneumoniae la causa más común de neumonía severa en niños y adultos en Europa y Estados Unidos (O'Brien et al., 2009). En general, la tasa de infecciones neumocócicas es mayor que la causada por cualquier otra bacteria patogénica. Como consecuencia, la OMS y las organizaciones como Wellcome Trust y Bill & Melinda Gates Foundation consideran las enfermedades neumocócicas como un problema mundial. La prevención de la enfermedad neumocócica invasiva (ENI) es una de las prioridades en salud pública debido a las altas tasas mundiales de morbilidad y mortalidad, especialmente en niños en países en vías de desarrollo (O'Brien et al., 2009). La inmunización es una propuesta segura y altamente eficiente para prevenir ENI. La activación de las cascadas del complemento por anticuerpos específicos conduce a la formación del componente clave C3b, el cual juega un papel crucial en la defensa del hospedador frente a neumococo, recubriendo los microorganismos y estimulando la fagocitosis. Actualmente, con el fin de obtener protección frente a los niños, las medidas profilácticas frente a la infección neumocócica están basadas en vacunas que contienen polisacáridos capsulares que pueden estar conjugadas con proteínas transportadoras (O'Brien y Levine, 2006). Sin embargo, una de las mayores desventajas de estas vacunas polisacarídica se debe a la amplia variabilidad neumocócica, con hasta 96 diferentes polisacáridos capsulares (CPS) descritos hasta la fecha (Park et al., 2015). Una limitación adicional es el intercambio capsular que se ha observado tras la introducción de las vacunas neumocócicas conjugadas (PCVs), lo cual resulta preocupante dado que estas cepas pueden emerger evitando la inmunidad inducida por la vacunación debido a la adquisición de genes capsulares de serotipos no vacunales (Aguinagalde et al., 2015; Brueggemann et al., 2007; Golubchik et al., 2012). Para evitar estos problemas, los esfuerzos en investigación se centran en nuevas proteínas de S. pneumoniae candidatas a vacunas, que puede proteger frente a los diferentes serotipos existentes. Uno de los objetivos principales de esta Tesis ha sido caracterizar la hidrolasa de la pared celular LytB de S. pneumoniae como potencial candidata a vacuna. LytB se localiza en sitios cercanos a los extremos polares y está expuesta a la superficie. Esta enzima tiene actividad Nacetilglucosaminidasa y desempeña un papel esencial en la separación de células hijas (De las Rivas et al., 2002; García et al., 1999). En términos de patogénesis, LytB participa en la formación de biofilm, unión de células epiteliales humanas y contribuye a la sepsis y neumonía, incrementando la capacidad de LytC para evitar la inmunidad mediada por el complemento y fagocitosis (Bai et al., 2014; Moscoso et al., 2006; Ramos-Sevillano et al., 2011). Desde la perspectiva profiláctica, LytB puede ser una diana prometedora para desarrollar una vacuna universal antineumocócica dado que el antisuero anti-LytB protege significativamente a ratones tras ser infectados con dosis letales de diferentes serotipos de neumococo (Wizemann et al., 2001)..