Ab initio analysis of the x-ray absorption spectrum of the myoglobin-carbon monoxide complex: Structure and vibrations

We present a comparison between Fe K-edge x-ray absorption spectra of carbonmonoxy-myoglobin and its simulation based on density-functional theory determination of the structure and vibrations and spectral simulation with multiple-scattering theory. An excellent comparison is obtained for the main part of the molecular structure without any structural fitting parameters. The geometry of the CO ligand is reliably determined using a synergic approach to data analysis. The methodology underlying this approach is expected to be especially useful in similar situations in which high-resolution data for structure and vibrations are available.Comment: 13 pages, 3 figure

The Mn site in Mn-doped Ga-As nanowires: an EXAFS study

We present an EXAFS study of the Mn atomic environment in Mn-doped GaAs nanowires. Mn doping has been obtained either via the diffusion of the Mn used as seed for the nanowire growth or by providing Mn during the growth of Au-induced wires. As a general finding, we observe that Mn forms chemical bonds with As but is not incorporated in a substitutional site. In Mn-induced GaAs wires, Mn is mostly found bonded to As in a rather disordered environment and with a stretched bond length, reminiscent of that exhibited by MnAs phases. In Au-seeded nanowires, along with stretched Mn-As coordination we have found the presence of Mn in a Mn-Au intermetallic compound.Comment: This is an author-created, un-copyedited version of an article accepted for publication in Semiconductor Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version is available online at doi:10.1088/0268-1242/27/8/08500

The debris flow hazard in the Lagarelle Creek in the eastern Umbria region, central Italy

International audienceThis paper analyzes the Lagarelle Creek watershed, situated in the Municipality of Vallo di Nera, in the eastern Umbria region, central Italy. In this part of the Region, narrow valleys and very steep slopes characterize the morphology of the Appennine ridge. The presence of strongly-tectonized rocky masses, subdivided by several joint systems, is the main cause for the formation of sorted debris deposits, which accumulate mainly along the topographic convergences. This determines the conditions for possible events of debris flows. According to previous studies, the basin of the Lagarelle Creek, has been classified as an area prone to a high hazard of debris flows (Regione dell'Umbria ? C.N.R. I.R.P.I., 1996). For this reason, systematic studies have been carried out on the whole watershed which, in this first phase, have examined the definition of the geological and morphological features of the zone, by means of the acquisition of cartographies and of field surveys, and the elaboration of the topographical data of the basin, by means of a digital model of the terrain. Once the potential triggering areas of debris flows were identified, an assessment of the mobilizable volumes possibly involved in a debris flow event was carried out. To perform such an assessment both the geomorphologic method proposed by Hungr (Hungr et al., 1984) and the empirical relations calibrated on debris flow events of the alpine arc were applied. The results obtained were compared with those derived from information supplied by the inhabitants of the small mountain village, who have described in detail the most important events of the last century

New Perspectives on Catalytic Hydrogen Production by the Reforming, Partial Oxidation and Decomposition of Methane and Biogas

The article provides a short review on catalyst-based processes for the production of hydrogen starting from methane, both of fossil origin and from sustainable processes. The three main paths of steam- and dry-reforming, partial oxidation and thermo-catalytic decomposition are briefly introduced and compared, above all with reference to the latest publications available and to new catalysts which obey the criteria of lower environmental impact and minimize the content of critical raw materials. The novel strategies based on chemical looping with CO2 utilization, membrane separation, electrical-assisted (plasma and microwave) processes, multistage reactors and catalyst patterning are also illustrated as the most promising perspective for CH4 reforming, especially on small and medium scale. Although these strategies should only be considered at a limited level of technological readiness, research on these topics, including catalyst development and process optimization, represents the crucial challenge for the scientific community

Recupero di un termine medico nelle Compositiones di Scribonio Largo (con annotazioni su la lettera Z in latino)

In the chapters 63 and 67, zona is to be emended to zerna. This word is one of the several clues about the presence of Z in the writing of ancient Latin. Probably, the term is of Etruscan origin and hints at a protuberance: originally, at the central part of the shield