Caratteristiche principali dell'emissione di galassie ellittiche

Fin dalla loro scoperta, le galassie ellittiche hanno sempre suscitato grande curiosità da parte degli astronomi, in quanto strutture dotate di dinamiche alquanto complesse. Spesso considerate meno affascinanti delle galassie a disco, esse vantano molteplici caratteristiche di carattere morfologico e radiativo; noi le osserviamo sulla Terra e fuori dall’atmosfera con ogni tipo di strumento, dato che tutto lo spettro elettromagnetico ne testimonia la presenza e, in molti casi, la piena attività nucleare. Obiettivo della presente dissertazione è fornire una panoramica generale riguardo le forme di emissione delle galassie ellittiche, approfondendo particolarmente i meccanismi principali e le modalità fisiche. Inizialmente vedremo brevemente come queste galassie vengono classificate e le leggi empiriche che ne descrivono alcuni importanti parametri osservativi; successivamente analizzeremo separatamente le tre bande (Ottica, X e Radio) in cui l’emissione è prominente, soffermandoci sui relativi meccanismi dominanti (rispettivamente: emissione di Corpo Nero, Bremsstrahlung e Sincrotrone) e le peculiarità

Mastcam-Z multispectral database from the Perseverance rover’s traverse in the Jezero crater floor, Mars (sols 0-380)

NASA’s Mars-2020 Perseverance rover spent its first year in Jezero crater studying the mafic lava flows of the Máaz formation and the ultramafic cumulates of the Séítah formation. Perseverance’s Mastcam-Z instrument, a pair of multispectral, stereoscopic zoom-lens cameras, provides broadband red/green/blue (RGB), narrowband visible to near-infrared color (VNIR, 440-1020 nm wavelength range). We compiled Mastcam-Z spectra from Perseverance’s exploration of the Jezero crater floor in the first 380 sols of its mission. Here, we provide a database of ~2400 representative spectra with extensive metadata, and the locations of the regions of interest (ROIs) from which the spectra were extracted. We also include “natural color” red, green, blue (RGB) images for context, “enhanced color images” derived by stretching narrowband images, and “decorrelation stretch” (DCS) images. This dataset can serve as a baseline to interpret future observations from Perseverance’s ongoing exploration of Jezero crater, Mars

Exploring the Diversity of the Bifidobacterial Population in the Human Intestinal Tract▿

Although the health-promoting roles of bifidobacteria are widely accepted, the diversity of bifidobacteria among the human intestinal microbiota is still poorly understood. We performed a census of bifidobacterial populations from human intestinal mucosal and fecal samples by plating them on selective medium, coupled with molecular analysis of selected rRNA gene sequences (16S rRNA gene and internally transcribed spacer [ITS] 16S-23S spacer sequences) of isolated colonies. A total of 900 isolates were collected, of which 704 were shown to belong to bifidobacteria. Analyses showed that the culturable bifidobacterial population from intestinal and fecal samples include six main phylogenetic taxa, i.e., Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis, Bifidobacterium pseudolongum, Bifidobacterium breve, and Bifidobacterium bifidum, and two species mostly detected in fecal samples, i.e., Bifidobacterium dentium and Bifidobacterium animalis subp. lactis. Analysis of bifidobacterial distribution based on age of the subject revealed that certain identified bifidobacterial species were exclusively present in the adult human gut microbiota whereas others were found to be widely distributed. We encountered significant intersubject variability and composition differences between fecal and mucosa-adherent bifidobacterial communities. In contrast, a modest diversification of bifidobacterial populations was noticed between different intestinal regions within the same individual (intrasubject variability). Notably, a small number of bifidobacterial isolates were shown to display a wide ecological distribution, thus suggesting that they possess a broad colonization capacity

Le regioni tra Costituzione e realtà politica

Atti del Convegno “I nuovi compiti della Regione e l’evoluzione del sistema istituzionale” (Torino, Fondazione Agnelli, 3 dicembre 1976), volto a studiare i rapporti fra gli organi dello Stato, il funzionamento delle istituzioni e la nascita di nuove strutture nella società con particolare riferimento alle Regioni e al governo locale.- Indice #7- Presentazione #9- Introduzione, Livio Paladin #11- Parte Prima Relazioni #15- Regioni e pluralismo, Franco Levi #17- I rapporti tra Stato e Regioni nella più recente legislazione nazionale, Sergio Bartole #33- I rapporti finanziari tra Regioni ed Enti Locali, Sabino Cassese #53- Tendenze della legislazione regionale all'allargamento delle competenze, Fabio Merusi #63- Amministrazione statale e regionale nella recente legislazione statale, Giuseppe Pericu #73- Parte Seconda Comunicazioni #95- Tendenze all'espansione delle competenze regionali e problemi della collaborazione tra le Regioni e lo Stato, Alberto Azzena #97- Note sulle leggi toscane fuori delle materie indicate nell'art. 117 della Costituzione, Massimo Carli #119- Regioni e tutela dell'ambiente, Antonio Carullo #126- Regioni a statuto speciale e Regioni a statuto ordinario, Giuseppe Contini #130- Tensioni intorno alle competenze regionali in Puglia, Enrico Dalfino #135- Parte Terza Interventi #141- Intervento di Norberto Bobbio #143- Intervento di Girolamo Caianiello #144- Intervento di Marco Cammelli #146- Intervento di Enzo Capaccioli #150- Intervento di Massimo Carli #152- Intervento di Giuseppe Contini #154- Intervento di Giovanni Cossu #158- Intervento di Fausto Cuocolo #160- Intervento di Antonio D’Atena #164- Intervento di Ugo De Siervo #167- Intervento di Guido Fanti #170- Intervento di Renato Federici #173- Intervento di Sergio Fois #176- Intervento di Gianfranco Mor #181- Intervento di Gianfranco Pasquino #184- Intervento di Fortunato Patera #187- Intervento di Franco Pizzetti #189- Intervento di Francesco Ciro Rampulla #195- Intervento di Mario Rey #199- Intervento di Mario Schinaia #204- Intervento di Gustavo Vignocchi #206- Intervento di Roberto Zaccaria #210- Parte Quarta Repliche conclusive #217- Replica conclusiva di Sergio Bartole #219- Replica conclusiva di Fabio Merusi #222- Replica conclusiva di Franco Levi #224- Elenco partecipanti #227

Regolith of the Crater Floor Units, Jezero Crater, Mars: Textures, Composition, and Implications for Provenance

International audienceA multi-instrument study of the regolith of Jezero crater floor units by the Perseverance rover has identified three types of regolith: fine-grained, coarse-grained, and mixed-type. Mastcam-Z, Wide Angle Topographic Sensor for Operations and eNgineering, and SuperCam Remote Micro Imager were used to characterize the regolith texture, particle size, and roundedness where possible. Mastcam-Z multispectral and SuperCam laser-induced breakdown spectroscopy data were used to constrain the composition of the regolith types. Fine-grained regolith is found surrounding bedrock and boulders, comprising bedforms, and accumulating on top of rocks in erosional depressions. Spectral and chemical data show it is compositionally consistent with pyroxene and a ferric-oxide phase. Coarse-grained regolith consists of 1-2 mm well-sorted gray grains that are found concentrated around the base of boulders and bedrock, and armoring bedforms. Its chemistry and spectra indicate it is olivine-bearing, and its spatial distribution and roundedness indicate it has been transported, likely by saltation-induced creep. Coarse grains share similarities with the olivine grains observed in the Séítah formation bedrock, making that unit a possible source for these grains. Mixed-type regolith contains fine- and coarse-grained regolith components and larger rock fragments. The rock fragments are texturally and spectrally similar to bedrock within the Máaz and Séítah formations, indicating origins by erosion from those units, although they could also be a lag deposit from erosion of an overlying unit. The fine- and coarse-grained types are compared to their counterparts at other landing sites to inform global, regional, and local inputs to regolith formation within Jezero crater. The regolith characterization presented here informs the regolith sampling efforts underway by Perseverance