571 research outputs found
The inhomogenous minima of indefinite binary quadratic forms
The authors conducted an experiment to determine whether the sequence of presentation of states in a health profile would affect the valuations assigned to them. The empirical task was part of a large standardized experiment involving 104 students. Thirteen health states were valued using two variations of the time-tradeoff method. At the group level, a small but distinct overall effect of the sequence of the tradeoffs was detected after accounting for discounting effects. The respondents were not preference-indifferent concerning the sequence of health states presented. Detailed analysis at the individual level indicated that the overall sequence effect was attributable to two groups of respondents who were sensitive to the sequence of events. One small group, referred to as "best-things-first" respondents, preferred the best years first; the other group, classified as "happy-end" respondents, preferred the reverse sequence. The majority of the respondents, however, were indifferent to the sequence. These results suggest that 1) in valuation experiments involving the time-tradeoff method and 2) in applying valuation results to the evaluation of real-life health consequences, a varying lifetime health profile may not be regarded as simply a chain of independent separately valued and discounted QALY periods. Even elementary valuation tasks cannot safely assume ignorance of prognosis, as the additive utility independence assumption of the QALY model does not hold. The sequence effect at least supplements the conventional general time-preference concept, and specific strategies are suggested to disentangle quantitatively the sequence effect and the time-preference effect
FM 047-02: a collisional pair of galaxies with a ring
Aims. We investigate the nature of the galaxy pair FM 047-02, which has been
proposed as an archetype of the Solitaire types of peculiar (collisional) ring
galaxies. Methods. The study is based on long-slit spectrophotometric data in
the range of 3500-9500 angstrons obtained with the Gemini Multi-ObjectComment: 07 pages, 06 figures, 02 tables. arXiv admin note: text overlap with
arXiv:1206.071
Patients First:Toward a Patient-Centered Instrument to Measure Impact of Chronic Pain
Background. Numerous instruments are available to measure the impact of chronic pain, yet most have been developed with little or no patient involvement. This study seeks to start bridging that gap by determining which health aspects or attributes (to be included in a future instrument) are considered most important by people with chronic pain. Objective. The goal of this study was to reveal which attributes reflecting impact of chronic pain are considered most important by people with chronic pain and to analyze differences in importance according to gender, age categories, diagnostic subgroups, and pain intensity categories. Design. This study used a sequential explanatory mixed-methods design: literature search, focus group meetings, and online survey. Methods. First, a literature search was performed to identify the attributes in existing instruments. In 68 instruments meeting inclusion criteria, 155 unique attributes were identified, 85 of which remained after applying the exclusion criteria. Second, 2 focus group meetings, with 6 and 4 patients, respectively, were held to verify that no attributes had been missed. Three attributes were subsequently added. Third, individuals with chronic pain were then sent an online survey through several patient organizations. Results. A total of 939 patients were asked to select the 8 attributes they deemed most important, which resulted in the following list: fatigue, social life, cramped muscles, sleeping, housekeeping, concentration, not being understood, and control over pain. The importance assigned to these 8 attributes varied slightly according to age, gender, and diagnostic subgroup. Limitations. Participation rate could not be established because of the online survey. Conclusions. Attributes reflecting impact of chronic pain deemed most important by patients are revealed. Importance of impact differs according to subgroups. The "patients-first" methodology used here revealed attributes that were not comprehensively covered in currently available instruments for measuring the impact of chronic pain
NACO/SAM observations of sources at the Galactic Center
Sparse aperture masking (SAM) interferometry combined with Adaptive Optics
(AO) is a technique that is uniquely suited to investigate structures near the
diffraction limit of large telescopes. The strengths of the technique are a
robust calibration of the Point Spread Function (PSF) while maintaining a
relatively high dynamic range. We used SAM+AO observations to investigate the
circumstellar environment of several bright sources with infrared excess in the
central parsec of the Galaxy. For our observations, unstable atmospheric
conditions as well as significant residuals after the background subtraction
presented serious problems for the standard approach of calibrating SAM data
via interspersed observations of reference stars. We circumvented these
difficulties by constructing a synthesized calibrator directly from sources
within the field-of-view. When observing crowded fields, this novel method can
boost the efficiency of SAM observations because it renders interspersed
calibrator observations unnecessary. Here, we presented the first NaCo/SAM
images reconstructed using this method.Comment: 8 pages, 10 figures, proceedings of the conference "Astrophysics at
High Angular Resolution" (AHAR-2011
Multi-criteria decision analysis (MCDA):testing a proposed MCDA framework for orphan drugs
BACKGROUND: Since the introduction of the orphan drugs legislation in Europe, it has been suggested that the general method of assessing drugs for reimbursement is not necessarily suitable for orphan drugs. The National Institute for Health and Clinical Excellence indicated that several criteria other than cost and efficacy could be considered in reimbursement decisions for orphan drugs. This study sought to explore the multi-criteria decision analysis (MCDA) framework proposed by (Orphanet J Rare Dis 7:74, 2012) to a range of orphan drugs, with a view to comparing the aggregate scores to the average annual cost per patient for each product, and thus establishing the merit of MCDA as a tool for assessing the value of orphan drugs in relation to their pricings. METHODS: An MCDA framework was developed using the nine criteria proposed by (Orphanet J Rare Dis 7:74, 2012) for the evaluation of orphan drugs, using the suggested numerical scoring system on a scale of 1 to 3 for each criterion. Correlations between the average annual cost of the drugs and aggregate MCDA scores were tested and plotted graphically. Different weightings for each of the attributes were also tested. A further analysis was conducted to test the impact of including the drug cost as an attribute in the aggregate index scores. RESULTS: In the drugs studied, the R (2), that statistically measures how close the data are to the fitted regression line was 0.79 suggesting a strong correlation between the drug scores and the average annual cost per patient. CONCLUSION: Despite several limitations of the proposed model, this quantitative study provided insight into using MCDA and its relationship to the average annual costs of the products
N-band Imaging of Seyfert Nuclei and the MIR-X-ray correlation
We present new mid-infrared (N-band) images of a sample of eight nearby
Seyfert galaxies. In all of our targets, we detect a central unresolved source,
which in some cases has been identified for the first time. In particular, we
have detected the mid-infrared emission from the active nucleus of NGC 4945,
which previously remained undetected at any wavelength but hard X-rays. We also
detect circumnuclear extended emission in the Circinus galaxy along its major
axis, and find marginal evidence for extended circumnuclear emission in NGC
3281.
The high spatial resolution (1.7") of our data allows us to separate the flux
of the nuclear point sources from the extended circumnuclear starburst (if
present). We complement our sample with literature data for a number of
non-active starburst galaxies, and relate the nuclear N-band flux to published
hard (2-10 kev) X-ray fluxes. We find tight and well-separated correlations
between nuclear N-band flux and X-ray flux for both Seyfert and starburst
nuclei which span over 3 orders of magnitude in luminosity. We demonstrate that
these correlations can be used as a powerful classification tool for galactic
nuclei.
For example, we find strong evidence against NGC 1808 currently harbouring an
active Seyfert nucleus based on its position in the mid-infrared-X-ray diagram.
On the other hand, we confirm that NGC 4945 is in fact a Seyfert 2 galaxy.Comment: 31 pages, incl. 4 figures, uses AASTex. Replaced with accepted
version after minor modifications. To appear in Ap
Elusive Active Galactic Nuclei
A fraction of active galactic nuclei do not show the classical Seyfert-type
signatures in their optical spectra, i.e. they are optically "elusive". X-ray
observations are an optimal tool to identify this class of objects. We combine
new Chandra observations with archival X-ray data in order to obtain a first
estimate of the fraction of elusive AGN in local galaxies and to constrain
their nature. Our results suggest that elusive AGN have a local density
comparable to or even higher than optically classified Seyfert nuclei. Most
elusive AGN are heavily absorbed in the X-rays, with gas column densities
exceeding 10^24 cm^-2, suggesting that their peculiar nature is associated with
obscuration. It is likely that in elusive AGN, the nuclear UV source is
completely embedded and the ionizing photons cannot escape, which prevents the
formation of a classical Narrow Line Region. Elusive AGN may contribute
significantly to the 30 keV bump of the X-ray background.Comment: accepted for publication in MNRAS Letters, 6 pages, 3 figures, typos
and references correcte
Dust and molecules in the Local Group galaxy NGC 6822. III. The first-ranked HII region complex Hubble V
We present maps of the first-ranked HII region complex Hubble V in the
metal-poor Local Group dwarf galaxy NGC 6822 in the first four transitions of
CO, the 158 micron transition of C+, the 21-cm line of HI, the Pa-beta line of
HII, and the continuum at 21 cm and 2.2 micron wavelengths. We have also
determined various integrated intensities, notably of HCO+ and near-IR H2
emission. Although Hubble X is located in a region of relatively strong HI
emission, our mapping failed to reveal any significant CO emission from it. The
relatively small CO cloud complex associated with Hubble V is comparable in
size to the ionized HII region. The CO clouds are hot (Tkin) = 150 K) and have
high molecular gas densities (n(H2) = 10**4 cm**-3) Molecular hydrogen probably
extends well beyond the CO boundaries. C+ column densities are more than an
order of magnitude higher than those of CO. The total mass of the complex is
about 10**6 M(sun) and molecular gas account for more than half of this. The
complex is excited by luminous stars reddened or obscured at visual, but
apparent at near-infrared wavelengths. The total embedded stellar mass may
account for about 10% of the total mass, and the mass of ionized gas for half
of that. Hubble V illustrates that modest star formation efficiencies may be
associated with high CO destruction efficiencies in low-metallicity objects.
The analysis of the Hubble V photon-dominated region (PDR) confirms in an
independent manner the high value of the CO-to-H2 conversion factor X found
earlier, characteristic of starforming low-metallicity regions.Comment: Accepted for publication in A&
Efeito de nĂveis de metionina sobre o nĂșmero de furos do disco germinal de ovos de codornas.
Com o objetivo de predizer resultados de incubatĂłrio, avaliou-se o nĂșmero de furos, feitos por espermatozoides, prĂłximos ao disco germinal de ovos de codornas que receberam diferentes nĂveis de metionina na dieta, formulada Ă base de milho e farelo de soja, sendo os tratamentos: T1 = sem adição de metionina, somente a aportada pelos alimentos, T2 = inclusĂŁo de metionina estabelecida de acordo com Rostagno et al. (2011) para a espĂ©cie e T3 = inclusĂŁo de 20% superior Ă recomendada para a espĂ©cie (T2). Os ovos foram coletados, processados e o nĂșmero de furos avaliado. Este trabalho nĂŁo encontrou diferença significativa para os nĂveis de metionina testados. With the aim to predict hatching results, the number of sperm holes in the germinal disc area of Japanese quail eggs submitted to different dietary methionine content were counted. Treatments were stablished as: T1 = no supplementary methionine (just from the ingredients content), T2 = methionine content according to Rostagno et al. (2011), and T3 = T2 plus 20% additional methionine. The eggs were collected, processed, and the number of holes in the germinal disc area were recorded. No significant difference was observed for the dietary methionine levels tested
A study of the remarkable galaxy system AM 546-324 (the core of Abell S0546)
We report first results of an investigation of the tidally disturbed galaxy
system AM\,546-324, whose two principal galaxies 2MFGC 04711 and AM\,0546-324
(NED02) were previously classified as interacting doubles. This system was
selected to study the interaction of ellipticals in a moderately dense
environment. We provide spectral characteristics of the system and present an
observational study of the interaction effects on the morphology, kinematics,
and stellar population of these galaxies. The study is based on long-slit
spectrophotometric data in the range of 4500-8000 obtained with
the Gemini Multi-Object Spetrograph at Gemini South (GMOS-S). We have used the
stellar population synthesis code STARLIGHT to investigate the star formation
history of these galaxies. The Gemini/GMOS-S direct r-G0303 broad band pointing
image was used to enhance and study fine morphological structures. The main
absorption lines in the spectra were used to determine the radial velocity.
Along the whole long-slit signal, the spectra of the Shadowy galaxy (discovered
by us), 2MFGC 04711, and AM\,0546-324 (NED02) resemble that of an early-type
galaxy. We estimated redshifts of z= 0.0696, z= 0.0693 and z= 0.0718,
corresponding to heliocentric velocities of 20\,141 km s, 20\,057 km
s, and 20\,754 km s for the Shadowy galaxy, 2MFGC 04711 and
AM\,0546-324 (NED02), respectively. ..
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