4,566 research outputs found
The Herschel Virgo Cluster Survey - II. Truncated dust disks in H I-deficient spirals
By combining Herschel-SPIRE observations obtained as part of the Herschel Virgo Cluster Survey with 21 cm Hi data from the literature, we investigate the role of the cluster environment on the dust content of Virgo spiral galaxies. We show for the first time that the extent of the dust disk is significantly reduced in Hi-deficient galaxies, following remarkably well the observed “truncation” of the Hi disk. The ratio of the submillimetre-to-optical diameter correlates with the Hi-deficiency, suggesting that the cluster environment is able to strip dust as well as gas. These results provide important insights not only into the evolution of cluster galaxies but also into the metal enrichment of the intra-cluster medium
Prediction of ductile fracture in anisotropic steels for pipeline applications
Large diameter steel pipelines for gas transportation may experience extreme overloads due to external actions such as soil sliding, faults movements, third part interactions. In these scenarios the material undergoes severe plastic strains which locally may reach the fracture limits. Due to the manufacturing process, the steels used in such applications have an anisotropic behavior both for plasticity and fracture. In this paper two steel grades have been characterized in view of anisotropic plastic fracture. Fracture tests have been planned to characterize the fracture behavior under different stress states and in different directions to define the anisotropic sensitivity. Finite element modelling, incorporating an anisotropic plasticity formulation, has been used to calculate the local fracture parameters in the specimens and to define the complete ductile fracture locus. An uncoupled damage evolution law has been finally used to evaluate the fracture limits on real pipelines failed in full scale laboratory tests. The strain to fracture prediction has been verified by local strain measurements on the fractured pipes. The model robustness has been also verified on global parameter predictions, such us the burst pressur
Multiple merging in the Abell cluster 1367
We present a dynamical analysis of the central ~1.3 square degrees of the
cluster of galaxies Abell 1367, based on 273 redshift measurements (of which
119 are news). From the analysis of the 146 confirmed cluster members we derive
a significantly non-Gaussian velocity distribution, with a mean location C_{BI}
= 6484+/-81 km/s and a scale S_{BI} = 891+/-58 km/s. The cluster appears
elongated from the North-West to the South-East with two main density peaks
associated with two substructures. The North-West subcluster is probably in the
early phase of merging into the South-East substructure (~ 0.2 Gyr before core
crossing). A dynamical study of the two subclouds points out the existence of a
group of star-forming galaxies infalling into the core of the South-East
subcloud and suggests that two other groups are infalling into the NW and SE
subclusters respectively. These three subgroups contain a higher fraction of
star-forming galaxies than the cluster core, as expected during merging events.
Abell 1367 appears as a young cluster currently forming at the intersection of
two filaments.Comment: 15 pages, 13 figures, 7 tables. Accepted for publication on A&A. High
resolution figures at http://goldmine.mib.infn.it/papers/a1367.htm
Politicisation of the international accounting standard setting process: evidence from the extractive industries
Purpose - The purpose of this paper is to provide a detailed example of the way in which extractive industries constituents participated in the setting of the international accounting standard for the extractive industries, IFRS 6 - Exploration for and Evaluation of Mineral Resources. Design/methodology/approach - A cross-section of extractive industries constituents is selected and their participation in the accounting standard setting process is examined via analysis of their comment letters and other interactions with the process. Findings - The paper contributes to our understanding of the politicised nature of accounting standard setting for the extractive industries. In doing so, it highlights the opportunities within the standard setting process through which key constituents can influence outcomes. Research limitations/implications - This paper reflects only a small sample of constituents involved in the standard setting process for the extractive industries and therefore focuses specifically on the relationships between key players selected
Beyond galaxy bimodality: the complex interplay between kinematic morphology and star formation in the local Universe
It is generally assumed that galaxies are a bimodal population in both star
formation and structure: star-forming galaxies are disks, while passive
galaxies host large bulges or are entirely spheroidal. Here, we test this
scenario by presenting a full census of the kinematic morphologies of a
volume-limited sample of galaxies in the local Universe extracted from the
MaNGA galaxy survey. We measure the integrated stellar line-of-sight velocity
to velocity dispersion ratio () for 4574 galaxies in the stellar mass
range . We show that at fixed
stellar mass, the distribution of is not bimodal, and that a simple
separation between fast and slow rotators is over-simplistic. Fast rotators are
a mixture of at least two populations, referred to here as dynamically-cold
disks and intermediate systems, with disks dominating in both total stellar
mass and number. When considering star-forming and passive galaxies separately,
the star-forming population is almost entirely made up of disks, while the
passive population is mixed, implying an array of quenching mechanisms. Passive
disks represent 30% (both in number and mass) of passive galaxies, nearly
a factor of two higher than that of slow rotators, reiterating that these are
an important population for understanding galaxy quenching. These results paint
a picture of a local Universe dominated by disky galaxies, most of which become
somewhat less rotation-supported upon or after quenching. While spheroids are
present to a degree, they are certainly not the evolutionary end-point for the
majority of galaxies.Comment: 17 pages (incl. 5 of appendix), accepted for publication in Ap
Morphological characterisation of malignant histiocytosis in a cat
Malignant histiocytosis (MH) is a progressive systemic neoplastic proliferation
of morphologically atypical histiocytes, well characterised in humans and dogs
but only recently identified in the cat. In all species, liver, lung, lymph nodes,
spleen and bone marrow are infiltrated by atypical histiocytes, and the disease
is rapidly fatal. The purpose of this study was to describe the clinical, histological,
immunohistochemical and ultrastructural findings of MH in a cat, together
with the diagnostic work-up and a list of differential diagnoses. Clinical evaluation
included a complete blood-cell count, serum biochemistry, urinalysis, serology
and ultrasound examination. The cat had clinical signs of depression,
thinness, dehydration, pale mucous membranes and tachycardia. Abdominal
ultrasonography revealed generalised splenomegaly and hepatomegaly. Necroscopy
showed whitish nodules, randomly scattered throughout the parenchyma
in the spleen and liver. The periportal lymph nodes were greatly enlarged
and the cut surface was uniformly greyish-white and translucent. Histological
examination revealed pleomorphic proliferation of large round tumour
cells, with numerous phagocytic vacuoles containing erytrocytes, leukocytes
and haemosiderin. By immunohistochemistry, positivity for lysozyme and
α1-antitrypsin and a scattered positivity for Mac 387 were observed. Ultrastructural
features of tumour cells included cytoplasmic lipid droplets, lysosomes and
phagolysosomes. MH in the cat needs to be differentiated from diffuse granulomatous
disease, non-Hodgkin’s lymphoma and Hodgkin’s-like disease. The
morphological features of the tumour cells, combined with immunohistochemical
and ultrastructural observation, are consistent with a diagnosis of MH in
the cat
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