1,525 research outputs found
Power Dependent Lineshape Corrections for Quantitative Spectroscopy
The Voigt profile - a convolution of a Gaussian and a Lorentzian - accurately
describes the absorption lines of atomic and molecular gases at low probe
powers. Fitting such to experimental spectra yields both the Lorentzian natural
linewidth and the Gaussian Doppler broadening. However, as the probe power
increases saturation effects introduce spurious power dependence into the
fitted Doppler width. Using a simple atomic model, we calculate power-dependent
corrections to the Voigt profile, which are parametrized by the Gaussian
Doppler width, the Lorentzian natural linewidth, and the optical depth. We show
numerically and experimentally that including the correction term substantially
reduces the spurious power dependence in the fitted Gaussian width.Comment: 4 pages, 3 figure
Quantitative atomic spectroscopy for primary thermometry
Quantitative spectroscopy has been used to measure accurately the
Doppler-broadening of atomic transitions in Rb vapor. By using a
conventional platinum resistance thermometer and the Doppler thermometry
technique, we were able to determine with a relative uncertainty of
, and with a deviation of from the
expected value. Our experiment, using an effusive vapour, departs significantly
from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly
absorbing molecules in a diffusive regime. In these circumstances, very
different systematic effects such as magnetic sensitivity and optical pumping
are dominant. Using the model developed recently by Stace and Luiten, we
estimate the perturbation due to optical pumping of the measured value
was less than . The effects of optical pumping on atomic and
molecular DBT experiments is mapped over a wide range of beam size and
saturation intensity, indicating possible avenues for improvement. We also
compare the line-broadening mechanisms, windows of operation and detection
limits of some recent DBT experiments
Photometry of a Galactic field at l = 232, b = -6. The old open cluster Auner 1, the Norma-Cygnus spiral arm and the signature of the warped Galactic Thick Disk
We perform a detailed photometric study of the stellar populations in a
Galactic Field at l = 232, b = -6 in the Canis Major (CMa) constellation. We
present the first U,B,V,I photometry of the old open cluster Auner1 and
determine it to be 3.25 Gyr old and to lie at 8.9 kpc from the Sun. In the
background of the cluster, at more than 9 kpc, we detect a young population
most probably associated to the Norma Cygnus spiral arm. Furthermore, we detect
the signature of an older population and identify its Turn Off and Red Giant
Branch. This population is found to have a mean age of 7 Gyrs and a mean
metallicity of Z = 0.006 . We reconstruct the geometry of the stellar
distribution and argue that this older population - often associated to the
Canis Major {\it galaxy}- belongs in fact to the warped old thin/thick disk
component along this line of sight.Comment: 19 pages, 7 eps figures (some degraded), accepted for publication in
the Astronomical Journa
Spiral structure in the outer galactic disk. I. The third galactic quadrant
We combine optical and radio observations to trace the spiral structure in the third quadrant of the Milky Way. The optical observations consist of a large sample of young open clusters and associations, whereas the radio observations consist of a survey of nearby and distant clouds observed in CO. Both the optical and radio samples are the largest ones thus far presented in the literature. We use this unique material to analyze the behavior of interstellar extinction and to trace the detailed structure of the third Galactic quadrant (TGQ).We find that the outer (Cygnus) grand design spiral arm is traced by stellar and CO components, while the Perseus arm is traced solely by CO and is possibly being disrupted by the crossing of the Local (Orion) arm. The Local arm is traced by CO and young stars toward l = 240° and extends for over 8 kpc along the line of sight reaching the outer arm. Finally, we characterize the Galactic warp and compare the geometries implied by the young stellar and CO components.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Patient partnership in quality improvement of healthcare services: Patients’ inputs and challenges faced
This research focuses on the perception of patients who participated in Continuous Quality Improvement Committees (CIC) regarding their contribution, lessons learned, and challenges encountered. The committees are engaged in a care partnership approach where patients are recognized for their experiential knowledge and treated as full members of the clinical team. Based on patient interviews, we conclude that they bring a structured and thoughtful vision of their experience. They identify themselves as real partners in the care process and are grateful for the opportunity to improve the care provided to other patients by using their own experience and by bringing changes to the patient-professional relationship, particularly in terms of communication. They also become better acquainted with the complexity of the health system and its organization. However, their participation in CICs raised two challenges. The first was their availability, as their professional schedules did not always allow them to participate in meetings. The second was their frustration with the slow decision-making process and implementation of necessary measures for quality improvement of healthcare and services. This study highlights the contribution of successful patient participation to quality of care improvement.
Experience Framework
This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this lens
Stellar populations in the Canis Major over-density
We performed a photometric multicolor survey of the core of the Canis Major
over-density at l 244, -8.0, reaching V = 22 and covering 0.3 x 1 degree. The
main aim is to unravel the complex mixture of stellar populations toward this
Galactic direction, where in the recent past important signatures of an
accretion event have been claimed to be detected. While our previous
investigations were based on disjointed pointings aimed at revealing the large
scale structure of the third Galactic Quadrant, we now focus on a complete
coverage of a smaller field centered on the Canis Major over-density. A large
wave-length baseline, in the UBVRI bands, allows us to build up a suite of
colour colour and colour magnitude diagrams, providing a much better diagnostic
tool to disentangle the stellar populations of the region. In fact, the simple
use of one colour magnitude diagram, widely employed in all the previous
studies defending the existence of the Canis Major galaxy, does not allow one
to separate the effects of the different parameters (reddening, age,
metallicity, and distance) involved in the interpretation of data, forcing to
rely on heavy modeling. In agreement with our previous studies in the same
general region of the Milky Way, we recognize a young stellar population
compatible with the expected structure and extension of the Local (Orion) and
Outer (Norma-Cygnus) spiral arms in the Third Galactic Quadrant. Moreover we
interpret the conspicuous intermediate-age metal poor population as belonging
to the Galactic thick disk, distorted by the effect of strong disk warping at
this latitude, and to the Galactic halo.Comment: 9 pages, 12 eps figures (some of them somewhat degraded in
resolution), accepted for publication in MNRA
Teores de nutrientes e produção de rúcula em função das concentrações de nitrogênio em solução nutritiva
O empirismo no uso das soluções nutritivas é freqüente. Muitas vezes a mesma solução nutritiva é usada para diferentes espécies baseando-se apenas em semelhanças morfológicas. No entanto esta situação pode proporcionar desequilíbrio nutricional prejudicando tanto a produção quanto a qualidade do produto face o acúmulo de nitrato. Foi conduzido um trabalho em sistema hidropônico - NFT, com o objetivo de avaliar o efeito da concentração de nitrogênio na solução nutritiva na produção, nos teores de nutrientes e de nitrato em folhas de rúcula (Eruca sativa). O trabalho foi conduzido na primavera de 2003. Foram avaliadas quatro concentrações de nitrogênio na solução nutritiva (60,8; 121,6; 182,5; 243,5 mg L-1) e três cultivares de rúcula (Cultivada, Folha Larga e Selvática), sob delineamento de blocos ao acaso, fatorial 4 x 3, com quatro repetições. A cv. Cultivada apresentou maior estatura e fitomassa fresca de folhas, não diferindo da 'Folha Larga' quanto a número de folhas, teor de nitrato nas folhas e fitomassa seca e fresca da raiz. Houve incremento de NO3-, N, Ca e P e diminuição de Mg, K e S com o aumento da concentração de N na solução nutritiva. O cultivo da cv. Cultivada na concentração de 93 mg L-1 é a mais recomendada em função da maior produtividade e baixo teor de nitrato.Empiricism in the use of nutrient solutions is frequent. Several times the same nutrient solution is used to grow different species based only on morphological similarities. This practice may lead to nutritional imbalances, affecting not only the production but also the quality of the product due to an accumulation of nitrate. An experiment under hydroponic conditions - the NFT system - was conducted with the aim of evaluating the effect of the concentration of nitrogen in the nutrient solution on the production and on the nutrient and nitrate contents of rocket (Eruca sativa) salad leaves. The experiment was carried out in spring 2003, in a randomized block design and in a 4 x 3 factorial design, with four replicates. Four nitrogen concentrations in the nutrient solution (60.8; 121.6; 182.5; 243.5 mg L-1) and three rocket salad cultivars (Cultivada, Folha Larga and Selvática) were evaluated. Cv. Cultivada produced the tallest plants and the highest leaf fresh fitomass, not differing from cv. 'Folha Larga' in the number of leaves, leaf nitrate content, root dry fitomass and root fresh fitomass. An increment in NO3, N, Ca and P and a reduction in Mg, K and S occurred when the concentration of N in the nutrient solution was increased. Cultivation of cv. Cultivada at the concentration of 93 mg L-1 is the most recommended as it provides the highest yield and low nitrate content
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