1,217 research outputs found
Discovery of periodic dips in the brightest hard X-ray source of M31 with EXTraS
We performed a search for eclipsing and dipping sources in the archive of the
EXTraS project - a systematic characterization of the temporal behaviour of
XMM-Newton point sources. We discovered dips in the X-ray light curve of 3XMM
J004232.1+411314, which has been recently associated with the hard X-ray source
dominating the emission of M31. A systematic analysis of XMM-Newton
observations revealed 13 dips in 40 observations (total exposure time 0.8
Ms). Among them, four observations show two dips, separated by 4.01 hr.
Dip depths and durations are variable. The dips occur only during
low-luminosity states (L erg s), while the
source reaches L erg s. We propose this
system to be a new dipping Low-Mass X-ray Binary in M31 seen at high
inclination (60-80), the observed dipping periodicity is
the orbital period of the system. A blue HST source within the Chandra error
circle is the most likely optical counterpart of the accretion disk. The high
luminosity of the system makes it the most luminous dipper known to date.Comment: 11 pages, 2 figures, 5 tables, accepted for publication in ApJ
Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13
NGC 7793 P13 is a variable (luminosity range ~100) ultraluminous X-ray source
(ULX) proposed to host a stellar-mass black hole of less than 15 M in
a binary system with orbital period of 64 d and a 18-23 M B9Ia
companion. Within the EXTraS project we discovered pulsations at a period of
~0.42 s in two XMM-Newton observations of NGC 7793 P13, during which the source
was detected at and erg
s (0.3-10 keV band). These findings unambiguously demonstrate that the
compact object in NGC 7793 P13 is a neutron star accreting at super-Eddington
rates. While standard accretion models face difficulties accounting for the
pulsar X-ray luminosity, the presence of a multipolar magnetic field with ~
few 10 G close to the base of the accretion column appears to
be in agreement with the properties of the system.Comment: 5 pages, 5 figures, 2 tables; Version accepted for publication in
MNRAS Letter
Intra-articular corticosteroid therapy in oligoarticular juvenile arthritis: our clinical experience
VST - VLT Survey Telescope Integration Status
The VLT Survey Telescope (VST) is a 2.6m aperture, wide field, UV to I
facility, to be installed at the European Southern Observatory (ESO) on the
Cerro Paranal Chile. VST was primarily intended to complement the observing
capabilities of VLT with wide-angle imaging for detecting and
pre-characterising sources for further observations with the VLT.Comment: 2 pages, 2 figures, conferenc
Rethinking the social impacts of the arts
The paper presents a critical discussion of the current debate over the social impacts of the arts in the UK. It argues that the accepted understanding of the terms of the debate is rooted in a number of assumptions and beliefs that are rarely questioned. The paper goes on to present the interim findings of a threeâyear research project, which aims to rethink the social impact of the arts, with a view to determining how these impacts might be better understood. The desirability of a historical approach is articulated, and a classification of the claims made within the Western intellectual tradition for what the arts âdoâ to people is presented and discussed
Swift J201424.9+152930: discovery of a new deeply eclipsing binary with 491 s and 3.4 h modulations
We report on the discovery of a new X-ray pulsator, Swift J201424.9+152930
(Sw J2014). Owing to its X-ray modulation at 491 s, it was discovered in a
systematic search for coherent signals in the archival data of the Swift X-ray
Telescope. To investigate the nature of Sw J2014, we performed multi-wavelength
follow-up observations with space-borne (Swift and XMM-Newton) and ground-based
(the 1.5-m Loiano Telescope and the 3.6-m Telescopio Nazionale Galileo)
instruments. The X-ray spectrum of Sw J2014 can be described by a hard and
highly absorbed power law. The optical observations made it possible to single
out the optical counterpart to this source, which displays several variable
emission lines and total eclipses lasting ~20 min. Total eclipses of similar
length were observed also in X-rays. The study of the eclipses, allowed us to
infer a second periodicity of 3.44 h, which we interpret as the orbital period
of a close binary system. We also found that the period has not significantly
changed over a ~7 yr timespan. Based on the timing signatures of Sw J2014, and
its optical and X-ray spectral properties, we suggest that it is a close binary
hosting an accreting magnetic white dwarf. The system is therefore a
cataclysmic variable of the intermediate polar type and one of the very few
showing deep eclipses.Comment: 12 pages, 8 figures, 5 tables; minor changes to match the final MNRAS
versio
Winter pruning: Effect on root density, root distribution and root/canopy ratio in vitis vinifera cv. Pinot Gris
As in any other plant, the grapevine roots play a vital role in terms of anchorage, uptake of water and nutrients, as well as storage and production of chemicals. Their behaviour and development depend on various factors, namely rootstock genetics, soil physical and chemical features, and field agronomic practices. Canopy management, involving techniques such as defoliation and pruning, could greatly influence root growth. To date, most of the studies on grapevine winter pruning have focused on the effects on yield and quality of the grapes achievable through different pruning systems and techniques, while knowledge regarding root distribution, development, and growth in relation to winter pruning is still not completely understood. In this context, the purpose of our study was to investigate the effect of winter pruning on the root system of field-grown Vitis vinifera cv. Pinot Gris grafted onto rootstock SO4. We compared two pruning treatments (pruned-P and no pruned-NP) and analysed the effect on root distribution and density, the root index, and the root sugar reserve. Root data were analysed in relation to canopy growth and yield, to elucidate the effect of winter pruning on the root/yield ratio. Our data indicated that: (1) winter pruning stimulated the root growth and distribution; (2) canopy development was not negatively affected by this technique; (3) no pruned treatment produced less growth of the roots but a larger canopy. Information regarding both root growth and root canopy ratio is important as it gives us an understanding of the relationship between the aerial and subterranean parts of the plant, how they compete, and finally, offers us the possibility to ponder on the cultural practices
Traditional landscape and rural development: comparative study in three terraced areas in northern, central and southern Italy to evaluate the efficacy of GAEC standard 4.4 of cross compliance
The recent National Strategic Plan 2007-2013 has introduced landscape as a strategic objective of the rural sector. This represents a minor revolution in the way of visualizing the role of the landscape, together with that of agriculture and the rural territory as a whole, and demonstrates the importance of treating the landscape with a systematic point of view. As part of the Efficond project, three sample areas have been identified, each of about 800-1000 hectares, in zones with important historical - cultural landscapes that are included in the National Catalogue of Historical Rural Landscapes. For each sample area a methodology has been applied, defined Historical Cultural Evaluation Approach, developed as part of a project for the monitoring of the Tuscan landscape that we have simplified and adapted. This methodology is based on the consideration that the landscape is the result of the centuries-old interaction between man and the environment, and so to define an element of the landscape as characteristic it is necessary to evaluate the land use dynamics and landscape changes that took place in the past, identifying those that have persisted for a long time, are slowly evolving or stabilized. The study of the historical landscape, which in the proposed methodology refers to the 50âs, has been done through the interpretation and analysis of aerial photographs taken on the GAI flight in 1954, and has allowed the characteristic, traditional and historical elements of that landscape to be identified and an insight to be gained into the cultural identity of the area. Through the creation of specific indices of density and intensity of the terracing obtained by photo-interpretation, field surveys and GIS elaborations, it was possible to classify the sample areas for this specific and important landscape element, compare the results in two periods and evaluate their frequency in the territory. Multi-temporal comparative analysis is being used increasingly often, especially for the study of territories of value, and in our case has been accompanied both by mapping of the landscape dynamics, which identifies the areas subject to transformations in the considered period, and by tables and figures that allow the evolution of a unit of land use to be followed, observing how this has evolved over time. The evaluation of these evolutionary dynamics has then been integrated with a set of indices, in part borrowed from landscape ecology, and in part specifically developed for areas historically shaped by man, which demonstrate that the landscape has become less fragmented and that the layout of fields has been adapted to a different agricultural model that has profoundly changed the structure of the traditional landscape. The efficacy of the laws protecting the characteristic elements of the landscape is strictly linked to the maintenance of its diversity and typicality and conservation of the complexity of the landscape mosaic. Its evaluation necessitates a historical analysis of the evolutionary dynamics conducted at a purely local level
Mechanisms of Progranulin Action and Regulation in Genitourinary Cancers.
The growth factor progranulin has emerged in recent years as a critical regulator of transformation in several cancer models, including breast cancer, glioblastomas, leukemias, and hepatocellular carcinomas. Several laboratories, including ours, have also demonstrated an important role of progranulin in several genitourinary cancers, including ovarian, endometrial, cervical, prostate, and bladder tumors, where progranulin acts as an autocrine growth factor thereby modulating motility and invasion of transformed cells. In this review, we will focus on the mechanisms of action and regulation of progranulin signaling in genitourinary cancers with a special emphasis on prostate and bladder tumors
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