Search results for "techniques"
showing 10 items of 4426 documents
Multiwavelength diagnostics of accretion in an X-ray selected sample of CTTSs
2011
Context. High resolution X-ray spectroscopy has revealed soft X-rays from high density plasma in classical T Tauri stars (CTTSs), probably arising from the accretion shock region. However, the mass accretion rates derived from the X-ray observations are consistently lower than those derived from UV/optical/NIR studies. Aims: We aim to test the hypothesis that the high density soft X-ray emission originates from accretion by analysing, in a homogeneous manner, optical accretion indicators for an X-ray selected sample of CTTSs. Methods: We analyse optical spectra of the X-ray selected sample of CTTSs and calculate the accretion rates based on measuring the Hα, Hβ, Hγ, He ii 4686 Å, He i 5016 …
High Resolution X-ray Spectroscopy of Pre-Main-Sequence Stars: TWA 5 and PZ Tel
2004
We report on the analysis of high resolution X-ray spectra of two pre-main-sequence stars: TWA 5 (observed with XMM-Newton) and PZ Telescopii (observed with Chandra/HETGS). TWA 5 is a classical T Tauri star in the TW Hydrae association while PZ Tel is a rapidly rotating weak-lined T Tauri star in the beta-Pictoris moving group. For both stars we have reconstructed the emission measure distribution and derived the coronal abundances to check for possible patterns of the abundances related to the first ionization potential of the various elements. We have also derived estimates of the plasma density from the analysis of the He-like triplets. We compare the characteristics of our targets with …
Gathering different marine geology data (seismics, acoustics, sedimentological) to investigate active fluid seepage (AFS) in the southern region of t…
2017
Active Fluid Seepage (AFS) at the seafloor is a global phenomenon associated with seafloor morphologies in different geodynamic contexts. Advances geophysical techniques have allowed geoscientists to characterise pockmarks, mounds and flares associated with AFS. We present a range of marine geological data acquired in the central Mediterranean Sea (northern Sicily continental margin, northwestern Sicily Channel and offshore the Maltese Islands), which allow us to identify AFSs. The AFSs are spatially distributed as clusters, aligned or isolated at different depths, ranging from few decametres offshore the Maltese Islands, up to 400 m offshore north Sicily and in the northwestern Sicily chan…
UNA PROCEDURA AUTOMATIZZATA PER LA DETERMINAZIONE DELLE CARATTERISTICHE MICROSTRUTTURALI DELLE SABBIE MEDIANTE ANALISI DI IMMAGINI DI SEZIONI SOTTILI
2012
È ben noto che il comportamento meccanico microscopico delle sabbie - e in generale dei terreni granulari - trae origine dalle loro caratteristiche microstrutturali, quali, per esempio, il numero di coordinazione dei singoli grani, l’indice di contatto intergranulare (grain contact ratio) e l’indice di addensamento dei grani (packing density index). Appare, quindi, di notevole importanza la determinazione degli indici predetti con alto grado di affidabilità e di ripetibilità. Lo studio dell’assetto dei contatti intergranulari e il calcolo degli indici che lo caratterizzano, viene condotta comunemente su immagini piane dell’insieme di grani mediante esame visuale e restituzione grafica assis…
Il quartiere Cappuccinelli a Trapani: per un intervento di retrofit sostenibile attraverso l’uso della vegetazione
2018
La riduzione del consumo di energia primaria e delle emissioni di CO2 nell’aria sono due obiettivi chiave delle politiche internazionali, come dimostrato dagli standard sempre più restrittivi in tema di efficienza energetica degli edifici. Il settore edilizio è considerato, infatti, uno dei più importanti settori strategici al fine di raggiungere questi due obiettivi e per questa ragione le politiche energetiche a livello globale si stanno indirizzando sempre più nella promozione di strategie finalizzate alla regolamentazione della sua efficienza attraverso il progetto di edifici sostenibili. L’articolo intende dimostrare, tramite la presentazione di un caso studio, l’efficacia e la complem…
Museum and Exhibition Design in the Digital Age
2013
From temples of sacred objects to repositories of colonial trophies and from monuments of civility to spaces for self-expression, the shape and the appeal of museums through history has been fashioned to hold particular collections of objects. Moreover the museums have been also designed to adapt to particular display techniques appropriate for a particular collection. In the last century, a period of structural reinvention in the design and shaping of the exhibitions, the museum making is challenging, creative, and complex. The ‘new museum making’ includes emotive exhibitions within communicative buildings in order to create ‘narrative experiences’ which integrate objects, spaces, and audi…
The ‘false vaults’ in the architecture of Sicily
2015
Between the end of the 17th century and the first decades of the 18th, Sicily was struck by several violent earthquakes. The total and partial collapse of monumental buildings produced a global debate involving various aspects of construction practice. One of the central topics of discussion was the construction of domes and large vaulted structures. Some architects studied the possibility of using so-called ‘false vaults’, a kind of lightweight structure created with a wooden frame, reed mats, and plaster. The technique was probably known by the 16th century and was used in a few major monuments, such as the dome of the Palermo Cathedral, in the mid-17th century. It was only after the Eart…
Modelling and Simulation in Science, Proceedings of the 6th International Workshop on Data Analysis in Astronomy >
2007
A MULTI-LAYER MODEL TO STUDY GENOME-SCALE POSITIONS OF NUCLEOSOMES
2007
The positioning of nucleosomes along chromatin has been implicated in the regulation of gene expression in eukaryotic cells, because packaging DNA into nucleosomes affects sequence accessibility. In this paper we propose a new model (called MLM) for the identification of nucleosomes and linker regions across DNA, consisting in a thresholding technique based on cut-set conditions. For this purpose we have defined a method to generate synthetic microarray data fully inspired from the approach that has been used by Yuan et al. Results have shown a good recognition rate on synthetic data, moreover, the $MLM$ shows a good agreement with the recently published method based on Hidden Markov Model …
Gamma-ray irradiation tests on CCD and CMOS sensors used in imaging techniques
2012
Technologically-enhanced electronic devices are used in various fields as space imaging or diagnostic techniques in medicine. The devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same apparatus, in particular in space applications. In this paper we report the results of a gamma irradiation tests on imaging sensors simulating the space radiation over a long time period. Two types of sensors are taken into consideration: CCD (Charge-Coupled Device) sensors and CMOS based on technology MOS (Metal Oxide semiconductor) used for the realization of transistors widely used in consumer electronics. The devices are supplied by Techno System (Italy),…