LIINUS/SERPIL: a design study for interferometric imaging spectroscopy at the LBT

LIINUS/SERPIL is a design study to augment LBTs interferometric beam combiner camera LINC-NIRVANA with imaging spectroscopy. The FWHM of the interferometric main beam at 1.5 micron will be about 10 mas, offering unique imaging and spectroscopic capabilities well beyond the angular resolution of current 8-10m telescopes. At 10 mas angular scale, e.g., one resolution element at the distance of the Galactic Center corresponds to the average diameter of the Pluto orbit (79 AU), hence the size of the solar system. Taking advantage of the LBT interferometric beam with an equivalent maximum diameter of 23 m, LIINUS/SERPIL is an ideal precursor instrument for (imaging) spectrographs at extremely large full aperture telescopes. LIINUS/SERPIL will be built upon the LINC-NIRVANA hardware and LIINUS/SERPIL could potentially be developed on a rather short timescale. The study investigates several concepts for the optical as well as for the mechanical design. We present the scientific promises of such an instrument together with the current status of the design study.Comment: 12 pages, SPIE conference proceeding, Orlando, 200

Metallicity evolution of AGNs from UV emission-lines based on a new index

We analyzed the evolution of the metallicity of the gas with the redshift for a sample of AGNs in a very wide redshift range (0<z<4) using ultraviolet emission-lines from the narrow-line regions (NLRs) and photoionization models. The new index C43=log(CIV+CIII])/HeII is suggested as a metallicity indicator for AGNs. Based on this indicator, we confirmed the no metallicity evolution of NLRs with the redshift pointed out by previous works. We found that metallicity of AGNs shows similar evolution than the one predicted by cosmic semi-analytic models of galaxy formation set within the Cold Dark Matter merging hierarchy (for z < 3). Our results predict a mean metallicity for local objects in agreement with the solar value (12+log(O/H)=8.69). This value is about the same that the maximum oxygen abundance value derived for the central parts of local spiral galaxies. Very low metallicity log(Z/Z_{\odot})~ -0.8 for some objects in the range 1.5 < z <3 is derived.Comment: 25 pages, 10 figures, accepted MNRA

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

From simple to even simpler, but not too simple:a head-to-head comparison of the Better-Worse and Drop-Down methods for measuring patient health status

BACKGROUND: We recently developed a novel, preference-based method (Better-Worse, BW) for measuring health status, expressed as a single metric value. We have since expanded it by developing the Drop-Down (DD) method. This article presents a head-to-head comparison of these two methods. We explored user feasibility, interpretability and statistics of the estimated coefficients, and distribution of the computed health-state values.METHODS: We conducted a cross-sectional online survey among patients with various diseases in the USA. The BW and DD methods were applied in the two arms of the study, albeit in reverse order. In both arms, patients first performed a descriptive task (Task 1) to rate their own health status according to the 12 items (each with 4 levels) in the CS-Base health-outcome instrument. They then performed Task 2, in which they expressed preferences for health states by the two methods. We then estimated coefficients for all levels of each item using logistic regression and used these to compute values for health states.RESULTS: Our total sample comprised 1,972 patients. Completion time was &lt; 2 min for both methods. Both methods were scored as easy to perform. All DD coefficients were highly significant from the reference level (P &lt; 0.001). For BW, however, only the second-level coefficient of "Cognition" was significantly different (P = 0.026). All DD coefficients were more precise with narrower confidence intervals than those of the BW method.CONCLUSIONS: Both the BW and DD are novel methods that are easy to apply. The DD method outperformed the BW method in terms of the precision of produced coefficients. Due to its task, it is free from a specific distorting factor that was observed for the BW method.</p

Sulphur abundance determinations in star-forming regions-I: Ionization Correction Factor

In the present work we used a grid of photoionization models combined with stellar population synthesis models to derive reliable Ionization Correction Factors (ICFs) for the sulphur in star-forming regions. These models cover a large range of nebular parameters and yielding ionic abundances in consonance with those derived through optical and infrared observational data of star-forming regions. From our theoretical ICFs, we suggested an {\alpha} value of 3.27 in the classical Stasinska formulae. We compared the total sulphur abundance in the gas phase of a large sample of objects by using our Theoretical ICF and other approaches. In average, the differences between the determinations via the use of the different ICFs considered are similar to the uncertainties in the S/H estimations. Nevertheless, we noted that for some objects it could reach up to about 0.3 dex for the low metallicity regime. Despite of the large scatter of the points, we found a trend of S/O ratio to decrease with the metallicity, independently of the ICF used to compute the sulphur total abundance.Comment: Accepted for publication in MNRAS, 21 pages, 8 figures, 5 table

An overview of the time trade-off method:concept, foundation, and the evaluation of distorting factors in putting a value on health

INTRODUCTION: Preference-based instruments measuring health status express the value of specific health states in a single number. One method used is time trade-off (TTO). Health-status values are key elements in calculating quality-adjusted life years (QALYs) and are pertinent for resource allocation. Since they are used in economic evaluations of healthcare, searching for a theoretical foundation of TTO in economics is justified. AREA COVERED: This paper provides an overview of TTO, including its relation to economic theory, and discusses biases and distortions, compiled from recent and older research. Inconsistencies between TTO and random utility theory were detected; The TTO is confounded by time preferences and by respondents' life expectancies. TTO is cognitively challenging, therefore guidance during the interviews is needed, producing interview effects. TTO does not measure one thing at a time, nor are the values independent of other states that are being valued in the same task. That is, TTO does not exhibit theoretical measurement properties such as unidimensionality and the invariance principle. EXPERT OPINION: We conclude that the TTO may be a pragmatic method of eliciting health state values, but the limitations in regard to measurement theory and practical elicitation problems makes it prone to inconsistencies and arbitrariness

JOINT LOADING OF LOWER EXTREMITIES DURING NORDIC WALKING COMPARED TO WALKING BASED ON KINETIC AND KINEMATIC DATA

Based on a higher cardio-pulmonary and cardio-vascular benefit and a promised reduction of mechanical load of the musculoskeletal system Nordic Walking (NW) shows an increased market potential. The present study should investigate whether there are differences in joint loading of lower extremities using an inverse dynamics approach between NW and Walking. In this experiment 15 subjects participated, who were already experienced with the NW technique. Kinematic data were collected using a 6-camera 3-dimensional Vicon System. Kinetic data were recorded using a Kistler force plate. Based on the findings it is to summarize, that the use of the poles during NW, performing the diagonal technique, do not lead to a reduction of joint loading of the lower extremities compared to Walking in general. Moreover for NW a higher knee joint loading during landing could be observed which is caused by the specific NW technique

Head-to-Head Comparison of EQ-5D-3L and EQ-5D-5L Health Values

The EQ-5D is a widely used preference-based instrument to measure health-related quality of life. Some methodological drawbacks of its three-level version (EQ-5D-3L) prompted development of a new format (EQ-5D-5L). There is no clear evidence that the new format outperforms the standard version.The objective of this study was to make a head-to-head comparison of the EQ-5D-3L and EQ-5D-5L in a discrete choice model setting giving special attention to the consistency and logical ordering of coefficients for the attribute levels and to the differences in health-state values.Using efficient designs, 240 pairs of EQ-5D-3L health states and 240 pairs of EQ-5D-5L health states were generated in a pairwise choice format. The study included 3698 Dutch general population respondents, analyzed their responses using a conditional logit model, and compared the values elicited by EQ-5D-3L and EQ-5D-5L for different health states.No inconsistencies or illogical ordering of level coefficients were observed in either version. The proportion of severe health states with low values was higher in the EQ-5D-5L than in the EQ-5D-3L, and the proportion of mild/moderate states was lower in the EQ-5D-5L than in the EQ-5D-3L. Moreover, differences were observed in the relative weights of the attributes.Overall distribution of health-state values derived from a large representative sample using the same measurement framework for both versions showed differences between the EQ-5D-3L and EQ-5D-5L. However, even small differences in the phrasing (language) of the descriptive system or in the valuation protocol can produce differences in values between these two versions.</p

Electron temperature fluctuations in NGC 346

The existence and origin of large spatial temperature fluctuations in HII regions and planetary nebulae are assumed to explain the differences between the heavy element abundances inferred from collisionally excited and recombination lines, although this interpretation remains significantly controversial. We investigate the spatial variation in electron temperature inside NGC 346, the brightest HII region in the Small Magellanic Cloud. Long slit spectrophotometric data of high signal-to-noise were employed to derive the electron temperature from measurements derived from localized observations of the [OIII]($\lambda4959 + \lambda5007)/\lambda4363$ ratio in three directions across the nebula. The electron temperature was estimated in 179 areas of 5$^{\prime\prime}\times1.5^{\prime\prime}$ of size distributed along three different declinations. A largely homogeneous temperature distribution was found with a mean temperature of 12 269 K and a dispersion of 6.1%. After correcting for pure measurements errors, a temperature fluctuation on the plane of the sky of $t^2_{\rm s} = 0.0021$ (corresponding to a dispersion of 4.5%) was obtained, which indicates a 3D temperature fluctuation parameter of $t^2 \approx 0.008$. A large scale gradient in temperature of the order of $-5.7\pm1.3$ K arcsec$^{-1}$ was found. The magnitude of the temperature fluctuations observed agrees with the large scale variations in temperature predicted by standard photoionization models, but is too small to explain the abundance discrepancy problem. However, the possible existence of small spatial scale temperature variations is not excluded.Comment: 6 pages, 5 figures, 2 table

Health Status of US Patients With One or More Health Conditions:Using a Novel Electronic Patient-reported Outcome Measure Producing Single Metric Measures

BACKGROUND: Most existing research studying health status impacted by morbidity has focused on a specific health condition, and most instruments used for measuring health status are neither patient-centered nor preference-based. This study aims to report on the health status of patients impacted by one or more health conditions, measured by a patient-centered and preference-based electronic patient-reported outcome measure.METHODS: A cross-sectional study was conducted among patients with one or more health conditions in the United States. A novel generic, patient-centered, and preference-based electronic patient-reported outcome measure: Château Santé-Base, was used to measure health status. Individual health state was expressed as a single metric number (value). We compared these health-state values between sociodemographic subgroups, between separate conditions, between groups with or without comorbidity, and between different combinations of multimorbidity.RESULTS: The total sample comprised 3913 patients. Multimorbidity was present in 62% of the patients. The most prevalent health conditions were pain (50%), fatigue/sleep problems (40%), mental health problems (28%), respiratory diseases (22%), and diabetes (18%). The highest (best) and lowest health-state values were observed in patients with diabetes and mental health problems. Among combinations of multimorbidity, the lowest values were observed when mental health problems were involved, the second lowest values were observed when fatigue/sleep problems and respiratory diseases coexisted.CONCLUSIONS: This study compared health status across various single, and multiple (multimorbidity and comorbidity) health conditions directly, based on single metric health-state values. The insights are valuable in clinical practice and policy-making.</p