185 research outputs found
Un modèle de qualité de la vie subjective adapté aux essais thérapeutiques : intérêt chez les patients dépressifs
Cet article présente les bases conceptuelles qui ont présidé à l'élaboration d'un questionnaire (« Profil de la Qualité de Vie Subjective » ou « PQVS ») évaluant la qualité de vie subjective des patients en pathologie somatique et psychiatrique. Une description de l'instrument précède les données concernant la validation de ce questionnaire ainsi que les résultats déjà obtenus sur environ 1500 sujets présentant des pathologies différentes. Les premiers résultats montrent qu'à chaque pathologie correspond un profil différent de patients; qu'il est possible, grâce à ce nouvel instrument d'évaluation, de mettre en évidence des changements spécifiques et parfois inattendus chez les patients; et qu'enfin, dans un certain nombre de cas, l'on peut dégager des hypothèses explicatives de ces changements.This article presents the conceptual foundations on which was built a questionnaire ("Profil de la Qualité de Vie Subjective" or "PQVS") designed to evaluate the subjective quality of life of patients marked by psychiatric or somatic pathology. Following a description of the instrument, the authors supply data relating to the questionnaire's validation, as well as the results obtained from a sampling of approximately 1,500 subjects with various pathologies. Initial results show that every pathology has a different patient profile. These results also point to the measuring instrument's ability to highlight specific and, at times, unexpected changes undergone by patients. Finally, the results enable the authors to advance hypotheses which may explain such changes in a certain number of cases
Herschel Search for O_2 toward the Orion Bar
We report the results of a search for molecular oxygen (O_2) toward the Orion Bar, a prominent photodissociation region at the southern edge of the H II region created by the luminous Trapezium stars. We observed the spectral region around the frequency of the O_2 NJ = 33-12 transition at 487 GHz and the 5_(4)-3_(4) transition at 774 GHz using the Heterodyne Instrument for the Far-Infrared on the Herschel Space Observatory. Neither line was detected, but the 3σ upper limits established here translate to a total line-of-sight O2 column density <1.5 × 10^(16) cm^(–2) for an emitting region whose temperature is between 30 K and 250 K, or <1 × 10^(16) cm^(–2) if the O_2 emitting region is primarily at a temperature of ≲100 K. Because the Orion Bar is oriented nearly edge-on relative to our line of sight, the observed column density is enhanced by a factor estimated to be between 4 and 20 relative to the face-on value. Our upper limits imply that the face-on O_2 column density is less than 4 × 10^(15) cm^(–2), a value that is below, and possibly well below, model predictions for gas with a density of 10^(4)-10^(5) cm^(–3) exposed to a far-ultraviolet flux 10^4 times the local value, conditions inferred from previous observations of the Orion Bar. The discrepancy might be resolved if (1) the adsorption energy of O atoms to ice is greater than 800 K; (2) the total face-on A V of the Bar is less than required for O_2 to reach peak abundance; (3) the O_2 emission arises within dense clumps with a small beam filling factor; or (4) the face-on depth into the Bar where O_2 reaches its peak abundance, which is density dependent, corresponds to a sky position different from that sampled by our Herschel beams
The Frequency of Barred Spiral Galaxies in the Near-IR
We have determined the fraction of barred galaxies in the H-band for a
statistically well-defined sample of 186 spirals drawn from the Ohio State
University Bright Spiral Galaxy survey. We find 56% of our sample to be
strongly barred at H, while another 16% is weakly barred. Only 27% of our
sample is unbarred in the near-infrared. The RC3 and the Carnegie Atlas of
Galaxies both classify only about 30% of our sample as strongly barred. Thus
strong bars are nearly twice as prevalent in the near-infrared as in the
optical. The frequency of genuine optically hidden bars is significant, but
lower than many claims in the literature: 40% of the galaxies in our sample
that are classified as unbarred in the RC3 show evidence for a bar in the
H-band, while for the Carnegie Atlas this fraction is 66%. Our data reveal no
significant trend in bar fraction as a function of morphology in either the
optical or H-band. Optical surveys of high redshift galaxies may be strongly
biased against finding bars, as bars are increasingly difficult to detect at
bluer rest wavelengths.Comment: LaTeX with AASTeX style file, 23 pages with 6 figures. Accepted for
publication in The Astronomical Journal (Feb. 2000
Herschel observations of interstellar chloronium
Using the Herschel Space Observatory's Heterodyne Instrument for the
Far-Infrared (HIFI), we have observed para-chloronium (H2Cl+) toward six
sources in the Galaxy. We detected interstellar chloronium absorption in
foreground molecular clouds along the sight-lines to the bright submillimeter
continuum sources Sgr A (+50 km/s cloud) and W31C. Both the para-H2-35Cl+ and
para-H2-37Cl+ isotopologues were detected, through observations of their
1(11)-0(00) transitions at rest frequencies of 485.42 and 484.23 GHz,
respectively. For an assumed ortho-to-para ratio of 3, the observed optical
depths imply that chloronium accounts for ~ 4 - 12% of chlorine nuclei in the
gas phase. We detected interstellar chloronium emission from two sources in the
Orion Molecular Cloud 1: the Orion Bar photodissociation region and the Orion
South condensation. For an assumed ortho-to-para ratio of 3 for chloronium, the
observed emission line fluxes imply total beam-averaged column densities of ~
2.0E+13 cm-2 and ~ 1.2E+13 cm-2, respectively, for chloronium in these two
sources. We obtained upper limits on the para-H2-35Cl+ line strengths toward H2
Peak 1 in the Orion Molecular cloud and toward the massive young star AFGL
2591. The chloronium abundances inferred in this study are typically at least a
factor ~10 larger than the predictions of steady-state theoretical models for
the chemistry of interstellar molecules containing chlorine. Several
explanations for this discrepancy were investigated, but none has proven
satisfactory, and thus the large observed abundances of chloronium remain
puzzling.Comment: Accepted for publication in the Astrophysical Journa
Heterodyne Array Receivers for Space and Ground Based Applications
The first heterodyne array receivers have been successfully built for ground-based telescopes and airborne observatories. In the talk we give a very quick overview of some prior heterodyne arrays. In particular, we will look at the innovations they introduced and how these could be applied to future large (100 to 1000 pixel) arrays or space missions. Then we will present the first detailed design for a space application, the Heterodyne Receiver for the Origins Space Telescope (HERO). HERO follows the traditional design, but limited cooling power and the limited electrical power of the satellite pose major challenges. Minor challenges are limited availability of space and weight. For the eight 3x3 pixel arrays of which 4 can operate simultaneously we attributed 20mW at 4.5K, 35mW at 35K and 205 W at the satellite temperature. Therefore we propose to use SiGe cryogenic low noise amplifiers, with a dissipation of about 0.5mW for 6 GHz bandwidth. The power of the backends also needs to be reduced drastically to about 1 W for 6 GHz bandwidth. CMOS ASIC backends are one option, ADC, followed by FFTs and ACCs another. To reduce the volume and mass, we propose the cover the RF bandwidth of 486 GHz to 2700 GHz in only 4 bands, each with about 50% relative width.The design might not only be a helpful starting point for any heterodyne array on a satellite, but the low heat and power consumption might be also an essential first step for large (100 to 1000 pixels) heterodyne arrays for ground based telescopes or simply a more energy efficient alternative for any ALMA single pixel or array receiver
The trail of water and the delivery of volatiles to habitable planets
Water is fundamental to our understanding of the evolution of planetary
systems and the delivery of volatiles to the surfaces of potentially habitable
planets. Yet, we currently have essentially no facilities capable of observing
this key species comprehensively. With this white paper, we argue that we need
a relatively large, cold space-based observatory equipped with a
high-resolution spectrometer, in the mid- through far-infrared wavelength range
(25-600~m) in order to answer basic questions about planet formation, such
as where the Earth got its water, how giant planets and planetesimals grow, and
whether water is generally available to planets forming in the habitable zone
of their host stars.Comment: Science white paper submitted to the Astro2020 Decadal Surve
Herschel Search for O2 Toward the Orion Bar
We report the results of a search for molecular oxygen (O2) toward the Orion
Bar, a prominent photodissociation region at the southern edge of the HII
region created by the luminous Trapezium stars. We observed the spectral region
around the frequency of the O2 N_J = 3_3 - 1_2 transition at 487 GHz and the
5_4 - 3_4 transition at 774 GHz using the Heterodyne Instrument for the Far
Infrared on the Herschel Space Observatory. Neither line was detected, but the
3sigma upper limits established here translate to a total line-of-sight O2
column density < 1.5 10^16 cm^-2 for an emitting region whose temperature is
between 30K and 250 K, or < 1 10^16 cm^-2 if the O2 emitting region is
primarily at a temperature of ~< 100 K. Because the Orion Bar is oriented
nearly edge-on relative to our line of sight, the observed column density is
enhanced by a factor estimated to be between 4 and 20 relative to the face-on
value. Our upper limits imply that the face-on O2 column density is less than 4
10^15 cm^-2, a value that is below, and possibly well below, model predictions
for gas with a density of 10^4 - 10^5 cm^-3 exposed to a far ultraviolet flux
10^4 times the local value, conditions inferred from previous observations of
the Orion Bar. The discrepancy might be resolved if: (1) the adsorption energy
of O atoms to ice is greater than 800 K; (2) the total face-on Av of the Bar is
less than required for O2 to reach peak abundance; (3) the O2 emission arises
within dense clumps with a small beam filling factor; or, (4) the face-on depth
into the Bar where O2 reaches its peak abundance, which is density dependent,
corresponds to a sky position different from that sampled by our Herschel
beams.Comment: 30 pages, 7 figures, 1 table. Accepted for publication in Ap
Odin observations of H2O in the Galactic Centre
The Odin satellite has been used to detect emission and absorption in the
557-GHz H2O line in the Galactic Centre towards the Sgr A* Circumnuclear Disk
(CND), and the Sgr A +20 km/s and +50 km/s molecular clouds. Strong broad H2O
emission lines have been detected in all three objects. Narrow H2O absorption
lines are present at all three positions and originate along the lines of sight
in the 3-kpc Spiral Arm, the -30 km/s Spiral Arm and the Local Sgr Spiral Arm.
Broad H2O absorption lines near -130 km/s are also observed, originating in the
Expanding Molecular Ring. A new molecular feature (the ``High Positive Velocity
Gas'' - HPVG) has been identified in the positive velocity range of ~ +120 to
+220 km/s, seen definitely in absorption against the stronger dust continuum
emission from the +20 km/s and +50 km/s clouds and possibly in emission towards
the position of Sgr A* CND. The 548-GHz H2_18O isotope line towards the CND is
not detected at the 0.02 K (rms) level.Comment: 5 pages, 3 figures, accepted by A&A, special Odin Letters issu
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