-
Article
Open AccessSpatial distribution of the risk of dengue fever in southeast Brazil, 2006-2007
Many factors have been associated with circulation of the dengue fever virus and vector, although the dynamics of transmission are not yet fully understood. The aim of this work is to estimate the spatial dist...
-
Article
Determination of Electron Flux Spectra in a Solar Flare with an Augmented Regularization Method: Application to Rhessi Data
Kontar et al. (2004) have shown how to recover mean source electron spectra \(\bar F(E)\) in solar flares through a p...
-
Article
Generalized Regularization Techniques with Constraints for the Analysis of Solar Bremsstrahlung X-ray Spectra
Hard X-ray spectra in solar flares provide knowledge of the electron spectrum that results from acceleration and propagation in the solar atmosphere. However, the inference of the electron spectra from solar X...
-
Chapter
Chromospheric Height and Density Measurements in a Solar Flare Observed with RHESSI
We obtain a theoretical description of the height (z) distribution of flare hard X-rays in the collisional thick-target model as a function of photon energy ε. This depends on the target atmosphere density struct...
-
Chapter
Empirical Correction of RHESSI Spectra for Photospheric Albedo and Its Effect on Inferred Electron Spectra
Photospheric Compton backscatter (albedo) makes a significant contribution to observed hard X-ray (HXR) spectral fluxes over the RHESSI energy range and should be allowed for in HXR spectral interpretation. Th...
-
Chapter
Nonuniform Target Ionization and Fitting Thick Target Electron Injection Spectra to RHESSI Data
Past analyses of flare hard X-ray (HXR) spectra have largely ignored the effect of nonuniform ionization along the electron paths in the thick-target model, though it is very significant for well-resolved spec...
-
Chapter
Chromospheric Height and Density Measurements in a Solar Flare Observed with RHESSI
We present an analysis of hard X-ray imaging observations from one of the first solar flares observed with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) spacecraft, launched on 5 February 2...
-
Article
Chromospheric Height and Density Measurements in a Solar Flare Observed with RHESSI – I. Theory
We obtain a theoretical description of the height (z) distribution of flare hard X-rays in the collisional thick-target model as a function of photon energy ε. This depends on the target atmosphere density struct...
-
Article
Nonuniform Target Ionization and Fitting Thick Target Electron Injection Spectra to RHESSI Data
Past analyses of flare hard X-ray (HXR) spectra have largely ignored the effect of nonuniform ionization along the electron paths in the thick-target model, though it is very significant for well-resolved spec...
-
Article
Empirical correction of RHESSI spectra for photospheric albedo and its effect on inferred electron spectra
Photospheric Compton backscatter (albedo) makes a significant contribution to observed hard X-ray (HXR) spectral fluxes over the RHESSI energy range and should be allowed for in HXR spectral interpretation. Th...
-
Article
Chromospheric Height and Density Measurements in a Solar Flare Observed with RHESSI – II. Data Analysis
We present an analysis of hard X-ray imaging observations from one of the first solar flares observed with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) spacecraft, launched on 5 February 2...
-
Chapter and Conference Paper
Inverse spectropolarimetric modelling of hot star wind structure and variability
-
Article
Inversion of Thick-Target Bremsstrahlung Spectra from Nonuniformly Ionised Plasmas
The effects of non-uniform plasma target ionisation on the spectrum of thick-target HXR bremsstrahlung from a non-thermal electron beam are analysed. In particular the effect of the target ionisation structure...
-
Chapter and Conference Paper
Using ISO to Probe the Acceleration of Wolf-Rayet Winds
Brown et al. (1997) and Ignace et al. (1997) have developed an inversion method to derive the wind velocity distribution from optically thin line profiles formed in spherically symmetric outflows. The method h...
-
Chapter
Die Volkswirtschaft der Vereinigten Staaten von Amerika
Volkswirte haben zum Glück nicht die Möglichkeit, mit echten Volkswirtschaften zu spielen, um ihren Forschungsdrang zu befriedigen. Statt dessen müssen sie sich mit „natürlichen Experimenten“ zufriedengeben, u...
-
Article
A possible mechanism governing the production and evolution of Ellerman bombs
A hydrodynamic-magnetofluid hybrid analysis of lower chromospheric shear flows in the Sun may explain the occurrence and time development of Ellerman bombs. The analysis assumes that the erupting material form...
-
Chapter
Wolf-Rayet Star Variability and Wind Inhomogeneities
The wind structure diagnostic possibilities offered by combined study of photo-, spectro-, and polari-metric variability are discussed using data from the Montreal group. These demand the presence in the wind ...
-
Article
Spectropolarimetric modelling of hot star wind structure
A short overview is given of some recent progress in the theory of spectropolarimetry as a diagnostic of axisymmetric hot star wind density and velocity structure, covering the inferences possible from broad b...
-
Article
Spatial fragmentation of solar flare plasma and beams
The observational and theoretical arguments for spatial fragmentation of the bulk of the thermal and non-thermal components of solar flare plasma are summarised. Observational aspects considered include XUV fi...
-
Chapter
Spatial Fragmentation of Solar Flare Plasma and Beams
The observational and theoretical arguments for spatial fragmentation of the bulk of the thermal and non-thermal components of solar flare plasma are summarised. Observational aspects considered include XUV fi...
