796 research outputs found
The spectroscopic evolution of the symbiotic-like recurrent nova V407 Cygni during its 2010 outburst. I. The shock and its evolution
On 2010 Mar 10, V407 Cyg was discovered in outburst, eventually reaching V< 8
and detected by Fermi. Using medium and high resolution ground-based optical
spectra, visual and Swift UV photometry, and Swift X-ray spectrophotometry, we
describe the behavior of the high-velocity profile evolution for this nova
during its first three months. The peak of the X-ray emission occurred at about
day 40 with a broad maximum and decline after day 50. The main changes in the
optical spectrum began at around that time. The He II 4686A line first appeared
between days 7 and 14 and initially displayed a broad, symmetric profile that
is characteristic of all species before day 60. Low-excitation lines remained
comparatively narrow, with v(rad,max) of order 200-400 km/s. They were
systematically more symmetric than lines such as [Ca V], [Fe VII], [Fe X], and
He II, all of which showed a sequence of profile changes going from symmetric
to a blue wing similar to that of the low ionization species but with a red
wing extended to as high as 600 km/s . The Na I D doublet developed a broad
component with similar velocity width to the other low-ionization species. The
O VI Raman features were not detected. We interpret these variations as
aspherical expansion of the ejecta within the Mira wind. The blue side is from
the shock penetrating into the wind while the red wing is from the low-density
periphery. The maximum radial velocities obey power laws, v(rad,max) t^{-n}
with n ~ 1/3 for red wing and ~0.8 for the blue. (truncated)Comment: Accepted for publication, A&A (submitted: 9 Oct 2010; accepted: 1 Dec
2010) in press; based on data obtained with Swift, Nordic Optical Telescope,
Ondrejov Observatory. Corrected typo, Fermi?LAT detection was at energies
above 100 MeV (with thanks to C. C. Cheung
A randomized, placebo-controlled trial of the benzoquinone idebenone in a mouse model of OPA1-related dominant optic atrophy reveals a limited therapeutic effect on retinal ganglion cell dendropathy and visual function
Dominant optic atrophy (DOA) arises from mutations in the OPA1 gene that promotes fusion of the inner mitochondrial membrane and plays a role in maintaining ATP levels. Patients display optic disc pallor, retinal ganglion cell (RGC) loss and bilaterally reduced vision. We report a randomized, placebo-controlled trial of idebenone at 2000 mg/kg/day in 56 Opa1 mutant mice (B6;C3-Opa1Q285STOP), with RGC dendropathy and visual loss, and 63 wildtype mice. We assessed cellular responses in the retina, brain and liver and RGC morphology, by diolistic labeling, Sholl analysis and quantification of dendritic morphometric features. Vision was assessed by optokinetic responses. ATP levels were raised by 0.57 nmol/mg (97.73%, p = 0.035) in brain from idebenone-treated Opa1 mutant mice, but in the liver there was an 80.35% (p = 0.011) increase in oxidative damage. NQO1 expression in Opa1 mutant mice was reduced in the brain (to 30.5%, p = 0.002) but not in retina, and neither expression level was induced by idebenone. ON-center RGCs failed to show major recovery, other than improvements in secondary dendritic length (by 53.89%, p = 0.052) and dendritic territory (by 2.22 × 104 μm2 or 90.24%, p = 0.074). An improvement in optokinetic response was observed (by 12.2 ± 3.2 s, p = 0.003), but this effect was not sustained over time. OFF-center RGCs from idebenone-treated wildtype mice showed shrinkage in total dendritic length by 2.40 mm (48.05%, p = 0.025) and a 47.37% diminished Sholl profile (p = 0.029). Visual function in wildtype idebenone-treated mice was impaired (2.9 fewer head turns than placebo, p = 0.007). Idebenone appears largely ineffective in protecting Opa1 heterozygous RGCs from dendropathy. The detrimental effect of idebenone in wildtype mice has not been previously observed and raises some concerns
Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon III. HD 50138
We analyse spectroscopic observations of the B[e] star HD 50138 (MWC 158,
V743 Mon, or IRAS 06491-0654), a member of the FS CMa group, obtained over the
last twenty years. Four different epochs are identified in the observational
data, where the variability of the spectral features is substantially
different. Additionally, two long periods of (3 000 +/- 500) and (5 000 +/-
1000) days are found in the variations of the equivalent widths of the H alpha
and [OI] 6300 A lines and radial velocities of the H alpha line violet peak.
Modest signatures of a regular period of ~34 days in the radial velocities of
the H alpha red peak and H beta central depression are found in the season
2013/2014. The H alpha V/R changes indicate a periodicity of ~50 days. The
correlations between individual spectral features significantly restricts the
model of the object and suggest that it is most likely a binary system with a
highly distorted disc with spiral arms around the primary component. At the
same time, no obvious signs of the secondary component has been found in the
object's spectrum
Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon; I. V2028 Cyg
We present results of nearly six years of spectroscopic observations of the
B[e] star V2028 Cyg. The presence of the cold-type absorption lines combined
with a hot-type spectrum indicate the binarity of this object. Since B[e] stars
are embedded in an extended envelope, the usage of common stellar atmosphere
models for the analysis is quite inappropriate. Therefore, we focus on the
analysis of the long-term spectral line variations in order to determine the
nature of this object. We present the time dependences of the equivalent width
and radial velocities of the H alpha line, [O I] 6300 A, Fe II 6427, 6433, and
6456 A lines. The bisector variations and line intensities are shown for the H
alpha line. The radial velocities are also measured for the absorption lines of
the K component. No periodic variation is found. The observed data show
correlations between the measured quantities, which can be used in future
modelling
Core components of mental health stigma reduction interventions in low- and middle-income countries: a systematic review
Aims
To identify and categorise core components of effective stigma reduction interventions in the field of mental health in low- and middle-income countries (LMICs) and compare these components across cultural contexts and between intervention characteristics.
Methods
Seven databases were searched with a strategy including four categories of terms ('stigma’, ‘mental health’, ‘intervention’ and ‘low- and middle-income countries’). Additional methods included citation chaining of all papers identified for inclusion, consultation with experts and hand searching reference lists from other related reviews. Studies on interventions in LMICs aiming to reduce stigma related to mental health with a stigma-related outcome measure were included. All relevant intervention characteristics and components were extracted and a quality assessment was undertaken. A ‘best fit’ framework synthesis was used to organise data, followed by a narrative synthesis.
Results
Fifty-six studies were included in this review, of which four were ineffective and analysed separately. A framework was developed which presents a new categorisation of stigma intervention components based on the included studies. Most interventions utilised multiple methods and of the 52 effective studies educational methods were used most frequently (n = 83), and both social contact (n = 8) and therapeutic methods (n = 3) were used infrequently. Most interventions (n = 42) based their intervention on medical knowledge, but a variety of other themes were addressed. All regions with LMICs were represented, but every region was dominated by studies from one country. Components varied between regions for most categories indicating variation between cultures, but only a minority of studies were developed in the local setting or culturally adapted.
Conclusions
Our study suggests effective mental health stigma reduction interventions in LMICs have increased in quantity and quality over the past five years, and a wide variety of components have been utilised successfully – from creative methods to emphasis on recovery and strength of people with mental illness. Yet there is minimal mention of social contact, despite existing strong evidence for it. There is also a lack of robust research designs, a high number of short-term interventions and follow-up, nominal use of local expertise and the research is limited to a small number of LMICs. More research is needed to address these issues. Some congruity exists in components between cultures, but generally they vary widely. The review gives an in-depth overview of mental health stigma reduction core components, providing researchers in varied resource-poor settings additional knowledge to help with planning mental health stigma reduction interventions
OWL-based acquisition and editing of computer-interpretable guidelines with the CompGuide editor
Computer-Interpretable Guidelines (CIGs) are the dominant medium for the delivery of clinical decision support, given the evidence-based nature of their source material. Therefore, these machine-readable versions have the ability to improve practitioner performance and conformance to standards, with availability at the point and time of care. The formalisation of Clinical Practice Guideline knowledge in a machine-readable format is a crucial task to make it suitable for the integration in Clinical Decision Support Systems. However, the current tools for this purpose reveal shortcomings with respect to their ease of use and the support offered during CIG acquisition and editing. In this work, we characterise the current landscape of CIG acquisition tools based on the properties of guideline visualisation, organisation, simplicity, automation, manipulation of knowledge elements, and guideline storage and dissemination. Additionally, we describe the CompGuide Editor, a tool for the acquisition of CIGs in the CompGuide model for Clinical Practice Guidelines that also allows the editing of previously encoded guidelines. The Editor guides the users throughout the process of guideline encoding and does not require proficiency in any programming language. The features of the CIG encoding process are revealed through a comparison with already established tools for CIG acquisition.COMPETE, Grant/Award Number: POCI-01-0145-FEDER-007043; FCT - Fundacao para a Ciencia e Tecnologia, Grant/Award Number: UID/CEC/00319/201
Reliability of Human Subject - Artificial System Interactions
Main problems related to reliability of interaction between human subject and artificial system (namely of the transportation character) are discussed. The paper consists of three mayor parts:The first one is devoted to the theoretical backgrounds of the problem from the both theory of system reliability and neurology/psychology views.Second part presents the discussion of relevant methodologies of the classification and prediction of the reliability decline. The methodology based on EEG pattern analysis is chosen as the appropriate one for the presented task. The key phenomenon of "micro-sleep" is discussed in detail.The last part presents some latest experimental results in context of presented knowledge. Proposals for the future studies are presented at the end of the presented article. The special interest should be devoted to the analysis and in-time prediction of fatal attention decreases and to the design and construction of the respective on-board applicable warning system
Physical theory of the twentieth century and contemporary philosophy
It has been shown that the criticism of Pauli as well as of Susskind and
Glogover may be avoided if the standard quantum-mechanical mathematical model
has been suitably extended. There is not more any reason for Einstein's
citicism, either, if in addition to some new results concerning Bell's
inequalities and Belifante's argument are taken into account. The ensemble
interpretation of quantum mechanics (or the hidden-variable theory) should be
preferred, which is also supported by the already published results of
experiments with three polarizers. Greater space in the text has been devoted
also to the discussion of epistemological problems and some philosophical
consequences.Comment: 12 page
Properties and nature of Be stars: 29. Orbital and long-term spectral variations of \gamma\ Cassiopei\ae
A detailed analysis of more than 800 electronic high-resolution spectra of
gamma Cas, which were obtained during a time interval of over 6000 days (16.84
yrs) at several observatories, documents the smooth variations in the density
and/or extend of its circumstellar envelope. We found a clear anticorrelation
between the peak intensity and FWHM of the H alpha emission, which seems to
agree with recent models of such emission lines. The main result of this study
is a confirmation of the binary nature of the object, determination of a
reliable linear ephemeris T_{min.RV} = HJD (2452081.90.6) +
(203.520.08)*E, and a rather definitive set of orbital elements. We
clearly demonstrated that the orbit is circular within the limits of accuracy
of our measurements and has a semi-amplitude of radial-velocity curve of
4.300.09 (km/s). No trace of the low-mass secondary was found. The time
distribution of our spectra does not allow a reliable investigation of rapid
spectral variations, which are undoubtedly present in the spectra. We postpone
this investigation for a future study, based on series of dedicated whole-night
spectral observations
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