394 research outputs found
Selective expression of interleukin 10, interferon gamma, and granulocyte-macrophage colony-stimulating factor in ovarian cancer biopsies.
Development status of a Laue lens project for gamma-ray astronomy
We report the status of the HAXTEL project, devoted to perform a design study
and the development of a Laue lens prototype. After a summary of the major
results of the design study, the approach adopted to develop a Demonstration
Model of a Laue lens is discussed, the set up described, and some results
presented.Comment: 11 pages, 11 figures, 2007 SPIE Conference on Optics for EUV, X-Ray,
and Gamma-Ray Astronomy II
Exploring the Hard X-/soft gamma-ray Continuum Spectra with Laue Lenses
The history of X-ray astronomy has shown that any advancement in our
knowledge of the X-ray sky is strictly related to an increase in instrument
sensitivity. At energies above 60 keV, there are interesting prospects for
greatly improving the limiting sensitivity of the current generation of direct
viewing telescopes (with or without coded masks), offered by the use of Laue
lenses. We will discuss below the development status of a Hard X-Ray focusing
Telescope (HAXTEL) based on Laue lenses with a broad bandpass (from 60 to 600
keV) for the study of the X-ray continuum of celestial sources. We show two
examplesof multi-lens configurations with expected sensitivity orders of
magnitude better ( photons cm s keV
at 200 keV) than that achieved so far. With this unprecedented sensitivity,
very exciting astrophysical prospects are opened.Comment: 4 pages, 10 figures, to be published in the Proc. of the 39th ESLAB
Symosium, 19-21 April 200
Gamma-ray lens development status for a European Gamma-Ray Imager
A breakthrough in the sensitivity level of the hard X-/gamma-ray telescopes,
which today are based on detectors that view the sky through (or not) coded
masks, is expected when focusing optics will be available also in this energy
range. Focusing techniques are now in an advanced stage of development. To date
the most efficient technique to focus hard X-rays with energies above 100 keV
appears to be the Bragg diffraction from crystals in transmission configuration
(Laue lenses). Crystals with mosaic structure appear to be the most suitable to
build a Laue lens with a broad passband, even though other alternative
structures are being investigated. The goal of our project is the development
of a broad band focusing telescope based on gamma-ray lenses for the study of
the continuum emission of celestial sources from 60 keV up to >600 keV. We will
report details of our project, its development status and results of our
assessment study of a lens configuration for the European Gamma Ray Imager
(GRI) mission now under study for the ESA plan "Cosmic Vision 2015-2025".Comment: 12 pages, 12 figure
KRAS status and risk of venous thromboembolic events in patients with metastatic colorectal cancer: a case-control study.
No abstract availabl
Focusing of gamma-rays with Laue lenses: first results
We report on the first results obtained from our development project of
focusing gamma-rays (60 keV) by using Laue lenses. The first lens prototype
model has been assembled and tested. We describe the technique adopted and the
lens focusing capabilities at about 100 keV.Comment: 8 pages 9 figures, to be published in SPIE Procs. 7011, 200
Educational effects of early or later secondary school tracking in Germany
This paper examines educational outcomes of pupils selected to secondary school types by different tracking regimes in a German state: Pupils are alternatively streamed after fourth grade or after sixth grade. Regression results indicate that, estimated on the mean, there are no negative effects of later tracking on educational outcomes in the middle of secondary school. Positive effects are observed for pupils with a less favorable family background. Quantile regressions reveal that the estimated effects of later tracking are positive for the lower quantiles but decrease monotonically over the conditional distribution of test scores
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