1,027 research outputs found
On the usefulness of finding charts Or the runaway carbon stars of the Blanco & McCarthy field 37
We have been recently faced with the problem of cross--identifying stars
recorded in historical catalogues with those extracted from recent fully
digitized surveys (such as DENIS and 2MASS). Positions mentioned in the old
catalogues are frequently of poor precision, but are generally accompanied by
finding charts where the interesting objects are flagged. Those finding charts
are sometimes our only link with the accumulated knowledge of past literature.
While checking the identification of some of these objects in several
catalogues, we had the surprise to discover a number of discrepancies in recent
works.The main reason for these discrepancies was generally the blind
application of the smallest difference in position as the criterion to identify
sources from one historical catalogue to those in more recent surveys. In this
paper we give examples of such misidentifications, and show how we were able to
find and correct them.We present modern procedures to discover and solve
cross--identification problems, such as loading digitized images of the sky
through the Aladin service at CDS, and overlaying entries from historical
catalogues and modern surveys. We conclude that the use of good finding charts
still remains the ultimate (though time--consuming) tool to ascertain
cross--identifications in difficult cases.Comment: 4 pages, 1 figure, accepted by A&
Detailed study of the microwave emission of the supernova remnant 3C 396
We have observed the supernova remnant 3C~396 in the microwave region using
the Parkes 64-m telescope. Observations have been made at 8.4 GHz, 13.5 GHz,
and 18.6 GHz and in polarisation at 21.5 GHz. We have used data from several
other observatories, including previously unpublished observations performed by
the Green Bank Telescope at 31.2 GHz, to investigate the nature of the
microwave emission of 3C 396. Results show a spectral energy distribution
dominated by a single component power law emission with . Data do not favour the presence of anomalous microwave emission coming
from the source. Polarised emission at 21.5 GHz is consistent with
synchrotron-dominated emission. We present microwave maps and correlate them
with infrared (IR) maps in order to characterise the interplay between thermal
dust and microwave emission. IR vs. microwave TT plots reveal poor correlation
between mid-infrared and microwave emission from the core of the source. On the
other hand, a correlation is detected in the tail emission of the outer shell
of 3C 396, which could be ascribed to Galactic contamination.Comment: published in MNRA
Virtual Reality Social Prediction Improvement and Rehabilitation Intensive Training (VR-SPIRIT) for paediatric patients with congenital cerebellar diseases: study protocol of a randomised controlled trial
Background: Patients with cerebellar malformations exhibit not only movement problems, but also important deficits in social cognition. Thus, rehabilitation approaches should not only involve the recovery of motor function but also of higher-order abilities such as processing of social stimuli. In keeping with the general role of the cerebellum in anticipating and predicting events, we used a VR-based rehabilitation system to implement a social cognition intensive training specifically tailored to improve predictive abilities in social scenarios (VR-Spirit). Methods/design: The study is an interventional randomised controlled trial that aims to recruit 42 children, adolescents and young adults with congenital cerebellar malformations, randomly allocated to the experimental group or the active control group. The experimental group is administered the VR-Spirit, requiring the participants to compete with different avatars in the reaching of recreational equipment and implicitly prompting them to form expectations about their playing preference. The active control group participates in a VR-training with standard games currently adopted for motor rehabilitation. Both trainings are composed by eight 45-min sessions and are administered in the GRAIL VR laboratory (Motekforce Link, Netherlands), an integrated platform that allows patients to move in natural and attractive VR environments. An evaluation session in VR with the same paradigm used in the VR-Spirit but implemented in a different scenario is administered at the beginning (T0) of the two trainings (T1) and at the end (T2). Moreover, a battery of neurocognitive tests spanning different domains is administered to all participants at T0, T2 and in a follow-up session after 2 months from the end of the two trainings (T3). Discussion: This study offers a novel approach for rehabilitation based on specific neural mechanisms of the cerebellum. We aim to investigate the feasibility and efficacy of a new, intensive, social cognition training in a sample of Italian patients aged 7-25 years with congenital cerebellar malformations. We expect that VR-Spirit could enhance social prediction ability and indirectly improve cognitive performance in diverse domains. Moreover, through the comparison with a VR-active control training we aim to verify the specificity of VR-Spirit in improving social perception skills. Trial registration: ISRCTN, ID: ISRCTN 22332873. Retrospectively registered on 12 March 2018
VOFilter, Bridging Virtual Observatory and Industrial Office Applications
VOFilter is an XML based filter developed by the Chinese Virtual Observatory
project to transform tabular data files from VOTable format into OpenDocument
format. VOTable is an XML format defined for the exchange of tabular data in
the context of the Virtual Observatory (VO). It is the first Proposed
Recommendation defined by International Virtual Observatory Alliance, and has
obtained wide support from both the VO community and many Astronomy projects.
OpenOffice.org is a mature, open source, front office applications suite with
the advantage of native support of industrial standard OpenDocument XML file
format. Using the VOFilter, VOTable files can be loaded in OpenOffice.org Calc,
a spreadsheet application, and then displayed and analyzed as other spreadsheet
files. Here, the VOFilter acts as a connector, bridging the coming VO with
current industrial office applications. Virtual Observatory and technical
background of the VOFilter are introduced. Its workflow, installation and usage
are presented. Existing problems and limitations are also discussed together
with the future development plans.Comment: Accepted for publication in ChJAA (9 pages, 2 figures, 185KB
Life cycle assessment of hydrogen-powered city buses in the High V.LO-City project: integrating vehicle operation and refuelling infrastructure
During the project High V.LO-City, which ended in December 2019, 14 hydrogen fuel cell buses were operated in four European cities. This paper aims at presenting total emissions through the lifetime of fuel cell buses with different hydrogen production options, including the refuelling stations. The environmental assessment of such bus system is carried out using the life cycle assessment methodology. Three hydrogen production pathways are investigated: water electrolysis, chlor-alkali electrolysis and steam methane reforming. Fuel economy during bus operation is around 10.25 KgH2/100 km, and the refuelling station energy demand ranges between 7 and 9 KWh/KgH2. To support the inventory stage, dedicated software tools were developed for collecting and processing a huge amount of bus data and refuelling station performance, for automating data entry and for impacts calculation. The results show that hydrogen-powered buses, compared to a diesel bus, have the potential to reduce emissions during the use phase, if renewables resources are used. On the other hand, impacts from the vehicle production, including battery pack and fuel cell stack, still dominate environmental load. Consequently, improving the emission profile of fuel cell bus system requires to promote clean electricity sources to supply a low-carbon hydrogen and to sharpen policy focus regarding life cycle management and to counter potential setbacks, in particular those related to problem shifting and to grid improvement. For hazardous emissions and resource use, the high energy intensity of mining and refining activities still poses challenges on how to further enhance the environmental advantages of fuel cells and battery packs
Influence of chitosan on the mechanical and biological properties of HDPE for biomedical applications
High density polyethylene (HDPE) is widely used in biomedical field, except when strong cell-material interactions and high mechanical properties are required. To address this pitfall, two kinds of chitosan in different amounts were used as filler in the present research. Composites were prepared by melt extrusion process and their microstructural, thermal and mechanical properties were widely investigated. Also roughness and wettability were studied, as features of paramount importance in dictating cell response.
Both types of chitosan endowed HDPE with higher Young modulus and lower elongation at break. Interestingly, fibroblast adhesion and viability were enhanced when a low amount of filler was used. The interaction of HDPE/chitosan composites with biological environment was investigated for the first time in order to assess the feasibility of these composites as materials for biomedical application
Characterisation of indeterminate focal breast lesions on grey-scale ultrasound: role of ultrasound elastography.
PURPOSE: This study was undertaken to evaluate the role of ultrasound (US)
elastography in characterising focal breast lesions classified as indeterminate
on B-mode US.
MATERIALS AND METHODS: Eighty-four focal breast lesions, 64 benign and 20
malignant (mean diameter, 15.1 mm), detected but not characterised on B-mode US
in 72 women, Breast Imaging Reporting and Data System (BI-RADS) US category 3
(n=56) or category 4 (n=28), were studied with US elastography and classified in
consensus by two radiologists according to a five-point colour scale.
Sensitivity, specificity and positive and negative predictive values (PPV and
NPV) of US elastography compared with conventional US were calculated in relation
to microhistology (n=67) and cytology (n=17), which were used as the reference
standard.
RESULTS: A total of 65/84 (77.4%) lesions were correctly classified as benign or
malignant using US elastography, whereas the remaining 19/84 (22.6%) were
incorrectly assessed. There were no statistically significant differences between
US elastography and B-mode US with regard to sensitivity (70% vs. 68.4%),
specificity (79.6% vs. 78.5%), PPV (51.8% vs. 48.1%) and NPV 89% vs. 89.5%
(p>0.5). By contrast, a statistically significant difference was noted in the
evaluation of BI-RADS 3 lesions, in which US elastography had 50% sensitivity,
86% specificity, 30% PPV and 93.5% NPV compared with BI-RADS 4 lesions (78.6%,
57.1%, 64.7% and 72.7%) (p<0.5).
CONCLUSIONS: The high NPV of US elastography may help reduce the use of biopsy in
BI-RADS 3 lesions, but its low PPV in BI-RADS 4 lesions does not allow avoidance
of biopsy on the basis of the US elastographic score alone in this group of
lesions
Multifrequency spectral analysis of extragalactic radio sources in the 33-GHz VSA catalogue: sources with flattening and upturn spectrum
We present an analysis of the spectral properties of the extragalactic radio sources in the nearly complete Very Small Array (VSA) sample at 33 GHz. Data from different surveys are used to study source spectra between 1.4 and 33 GHz. We find that, in general, spectra cannot be well described by a single power law in the range of frequencies considered. In particular, most of the VSA sources that are steep between 1.4 and 5 GHz, show a spectral flattening at ν > 5 GHz. We identify 20 objects (19 per cent of the sample) clearly characterized by an upturn spectrum, i.e. a spectrum falling at low frequencies (ν less than or similar to 5 GHz) and inverted at higher frequencies. Spectra with high-frequency flattening or upturn shape are supposed to occur when the emission from the active galactic nucleus (AGN) compact core begins to dominate over the component from extended lobes. This picture fits well with the AGN unified scheme, for objects observed at intermediate viewing angles of the AGN jet. Finally, we discuss implications that this class of sources can have on future cosmic microwave background observations at high resolution
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