162 research outputs found
Digital infra-red image processing
This paper describes a general approach to the digital processing of infra-red images, from data acquisition to data
use. The main steps of this processing are developped . Emphasis is placed on the pre-processing which reduces the
systematic radiometric errors and the considerable random noise inherent to infra-red images. It is then shown that,
with such a pre processing, classical techniques used for image in the visible domain become practicable . Each
process is explained in theory and illustrated with a practical example.Cet article présente une approche générale du traitement numérique des images infrarouges de l'acquisition à
l'utilisation des données. Les principales étapes d'un tel traitement y sont développées . L'accent est mis sur les
prétraitements qui visent à diminuer les erreurs radiométriques et le fort bruit aléatoire qui caractérisent les images
infrarouges . Il est ensuite montré comment l'application de tels prétraitements permet d'utiliser efficacement des
méthodes classiquement mises en oeuvre pour des images du domaine visible . Chaque traitement, expliqué d'un
point de vue théorique, est illustré par un exemple concret
Formation and Evolution of the Disk System of the Milky Way: [alpha/Fe] Ratios and Kinematics of the SEGUE G-Dwarf Sample
We employ measurements of the [alpha/Fe] ratio derived from low-resolution
(R~2000) spectra of 17,277 G-type dwarfs from the SEGUE survey to separate them
into likely thin- and thick-disk subsamples. Both subsamples exhibit strong
gradients of orbital rotational velocity with metallicity, of opposite signs,
-20 to -30 km/s/dex for the thin-disk and +40 to +50 km/s/dex for the
thick-disk population. The rotational velocity is uncorrelated with
Galactocentric distance for the thin-disk subsample, and exhibits a small trend
for the thick-disk subsample. The rotational velocity decreases with distance
from the plane for both disk components, with similar slopes (-9.0 {\pm} 1.0
km/s/kpc). Thick-disk stars exhibit a strong trend of orbital eccentricity with
metallicity (about -0.2/dex), while the eccentricity does not change with
metallicity for the thin-disk subsample. The eccentricity is almost independent
of Galactocentric radius for the thin-disk population, while a marginal
gradient of the eccentricity with radius exists for the thick-disk population.
Both subsamples possess similar positive gradients of eccentricity with
distance from the Galactic plane. The shapes of the eccentricity distributions
for the thin- and thick-disk populations are independent of distance from the
plane, and include no significant numbers of stars with eccentricity above 0.6.
Among several contemporary models of disk evolution we consider, radial
migration appears to have played an important role in the evolution of the
thin-disk population, but possibly less so for the thick disk, relative to the
gas-rich merger or disk heating scenarios. We emphasize that more physically
realistic models and simulations need to be constructed in order to carry out
the detailed quantitative comparisons that our new data enable.Comment: Accepted for publication in ApJ, 18 pages, 12 figures, 2 tables,
emulateapj forma
Report of Second Meeting for the Purpose of Obtaining the Views of the Three Affiliated Tribes of the Fort Berthold Reservation on the Lieu Lands Offered by the Secretary of War, 1946
Report of the second meeting held in the office of Assistant Secretary of the Interior C. Girard Davidson for the purpose of obtaining the views of the Three Affiliated Tribes of the Fort Berthold Reservation of the lieu lands offered by the Secretary of War. Includes a list of attendees and a transcript of the meeting discussing the Three Affiliated Tribes\u27 rejection of the offer of lieu lands made by the Secretary of Interior and Department of War to the Fort Berthold Reservation.
See also:
Report of Meeting for the Purpose of Obtaining the Views of the Three Affiliated Tribes of the Fort Berthold Reservation on the Lieu Lands Offered by the Secretary of War, 1946https://commons.und.edu/langer-papers/1147/thumbnail.jp
Humoral and Cell-Mediated Immunity to Pandemic H1N1 Influenza in a Canadian Cohort One Year Post-Pandemic: Implications for Vaccination
We evaluated a cohort of Canadian donors for T cell and antibody responses against influenza A/California/7/2009 (pH1N1) at 8-10 months after the 2nd pandemic wave by flow cytometry and microneutralization assays. Memory CD8 T cell responses to pH1N1 were detectable in 58% (61/105) of donors. These responses were largely due to cross-reactive CD8 T cell epitopes as, for those donors tested, similar recall responses were obtained to A/California 2009 and A/PR8 1934 H1N1 Hviruses. Longitudinal analysis of a single infected individual showed only a small and transient increase in neutralizing antibody levels, but a robust CD8 T cell response that rose rapidly post symptom onset, peaking at 3 weeks, followed by a gradual decline to the baseline levels seen in a seroprevalence cohort post-pandemic. The magnitude of the influenza-specific CD8 T cell memory response at one year post-pandemic was similar in cases and controls as well as in vaccinated and unvaccinated donors, suggesting that any T cell boosting from infection was transient. Pandemic H1-specific antibodies were only detectable in approximately half of vaccinated donors. However, those who were vaccinated within a few months following infection had the highest persisting antibody titers, suggesting that vaccination shortly after influenza infection can boost or sustain antibody levels. For the most part the circulating influenza-specific T cell and serum antibody levels in the population at one year post-pandemic were not different between cases and controls, suggesting that natural infection does not lead to higher long term T cell and antibody responses in donors with pre-existing immunity to influenza. However, based on the responses of one longitudinal donor, it is possible for a small population of pre-existing cross-reactive memory CD8 T cells to expand rapidly following infection and this response may aid in viral clearance and contribute to a lessening of disease severity
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study
Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection
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