THEMIS as particle detector: Spectropolarimetry of solar flares

The progressive phases of three solar flares have beenobserv ed with THEMIS in July 2000, using the multiline spectropolarimetric MTR mode. A preliminary analysis of the characteristics of the polarization of the Hα and Hβ lines observed at the beginning of the progressive phase of one of these flares is presented

Sleeping arrangements and mass distribution of bed nets in six districts in central and northern Mozambique

OBJECTIVE: Universal coverage with insecticide-treated bed nets is a cornerstone of modern malaria control. Mozambique has developed a novel bed net allocation strategy, where the number of bed nets allocated per household is calculated on the basis of household composition and assumptions about who sleeps with whom. We set out to evaluate the performance of the novel allocation strategy. METHODS: 1,994 households were visited during household surveys following two universal coverage bed net distribution campaigns in Sofala and Nampula Provinces in 2010-2013. Each sleeping space was observed for the presence of a bed net, and the sleeping patterns for each household were recorded. The observed coverage and efficiency were compared to a simulated coverage and efficiency had conventional allocation strategies been used. A composite indicator, the product of coverage and efficiency, was calculated. Observed sleeping patterns were compared with the sleeping pattern assumptions. RESULTS: In households reached by the campaign, 93% (95% CI: 93-94%) of sleeping spaces in Sofala and 84% (82-86%) in Nampula were covered by campaign bed nets. The achieved efficiency was high, with 92% (91-93%) of distributed bed nets in Sofala and 93% (91-95%) in Nampula covering a sleeping space. Using the composite indicator, the novel allocation strategy outperformed all conventional strategies in Sofala and was tied for best in Nampula. The sleeping pattern assumptions were completely satisfied in 66% of households in Sofala and 56% of households in Nampula. The most common violation of the sleeping pattern assumptions was that male children 3-10 years of age tended not to share sleeping spaces with female children 3-10 or 10-16 years of age. CONCLUSIONS: The sleeping pattern assumptions underlying the novel bed net allocation strategy are generally valid, and net allocation using these assumptions can achieve high coverage and compare favorably with conventional allocation strategies. This article is protected by copyright. All rights reserved

Electron density and temperature in the solar corona from multifrequency radio imaging

Context. The 2D images obtained through rotational aperture synthesis with the Nançay Radioheliograph are suitable for quantitative exploitation. First results are presented. Aims. We study the variations of the quiet corona in brightness and size during an 8-year period and derive electron density and temperature in the corona. Methods. Images at 6 frequencies between 150 and 450 MHz for 183 quiet days between 2004 and 2011 were used. Measurements of the brightness temperature Tb beyond the limb allowed coronal density models to be derived in both EW and NS radial directions, with a weak dependence on the electron temperature. The total ranges in the heliocentric distance r are 1.15–1.60 R⊙ (EW) and 1.0–1.4 R⊙ (NS). The agreement between results from different frequencies, in the ranges of r where there is overlapping shows the robustness of the method. The electron temperature, in turn, can be derived from the comparison of the observed mean spectra on the disk with those predicted through transfer calculations from the density models derived from limb observations. Results. The widths of the brightness profiles that were averaged yearly have minima at cycle minimum (2008–2009). These minima are more pronounced for EW profiles than for NS ones. The derived yearly-averaged density models along equatorial and polar diameters are consistent with isothermal and hydrostatic models. They are characterized by their density value n0 extrapolated down to the base of the corona and their scale-height temperature TH. Changes in n0 and TH with solar cycle are given for equatorial and polar regions. The kinetic temperature Te of electrons in the corona (~0.62 MK) is found to be significantly less than TH (~1.5 MK). This implies an ion temperature Ti ~ 2.2 MK. Conclusions. The yearly-averaged variations of these models are less than the dispersion between models derived from other techniques, such as white light and EUV observations, partly because these two techniques are not time-averaged, and they refer to particular days. The radio models are generally less dense, which is compatible with isothermal hydrostatic equilibrium in their range of heliocentric distances, and they show different behaviors with the solar cycle in the equatorial or polar radial directions. The electron kinetic temperature Te is substantially less than TH

Morphology of the quiet Sun between 150 and 450 MHz as observed with the Nançay radioheliograph

International audienc

Electron density and temperature in the solar corona from multifrequency radio imaging

Context. The 2D images obtained through rotational aperture synthesis with the Nançay Radioheliograph are suitable for quantitative exploitation. First results are presented. Aims. We study the variations of the quiet corona in brightness and size during an 8-year period and derive electron density and temperature in the corona. Methods. Images at 6 frequencies between 150 and 450 MHz for 183 quiet days between 2004 and 2011 were used. Measurements of the brightness temperature Tb beyond the limb allowed coronal density models to be derived in both EW and NS radial directions, with a weak dependence on the electron temperature. The total ranges in the heliocentric distance r are 1.15–1.60 R⊙ (EW) and 1.0–1.4 R⊙ (NS). The agreement between results from different frequencies, in the ranges of r where there is overlapping shows the robustness of the method. The electron temperature, in turn, can be derived from the comparison of the observed mean spectra on the disk with those predicted through transfer calculations from the density models derived from limb observations. Results. The widths of the brightness profiles that were averaged yearly have minima at cycle minimum (2008–2009). These minima are more pronounced for EW profiles than for NS ones. The derived yearly-averaged density models along equatorial and polar diameters are consistent with isothermal and hydrostatic models. They are characterized by their density value n0 extrapolated down to the base of the corona and their scale-height temperature TH. Changes in n0 and TH with solar cycle are given for equatorial and polar regions. The kinetic temperature Te of electrons in the corona (~0.62 MK) is found to be significantly less than TH (~1.5 MK). This implies an ion temperature Ti ~ 2.2 MK. Conclusions. The yearly-averaged variations of these models are less than the dispersion between models derived from other techniques, such as white light and EUV observations, partly because these two techniques are not time-averaged, and they refer to particular days. The radio models are generally less dense, which is compatible with isothermal hydrostatic equilibrium in their range of heliocentric distances, and they show different behaviors with the solar cycle in the equatorial or polar radial directions. The electron kinetic temperature Te is substantially less than TH

The structure of solar radio noise storms

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Pituitary disease in MEN type 1 (MEN1): Data from the France-Belgium MEN1 multicenter study

To date, data on pituitary adenomas in MEN type 1 (MEN1) still have to be evaluated. We analyzed the data of a large series of 324 MEN1 patients from a French and Belgian multicenter study. Data on pituitary disease were compared with those from 110 non-MEN1 patients with pituitary adenomas, matched for age, year of diagnosis, and follow-up period. Genetic analysis of the MEN1 gene was performed in 197 of the MEN1 patients. In our MEN1 series, pituitary disease occurred in 136 of 324 (42%), less frequently than hyperparathyroidism (95%, P < 0.001) and endocrine enteropancreatic tumors (54%, P < 0.01). Mean age of onset of pituitary tumors was 38.0 +/- 15.3 yr (range, 12-83 yr). Pituitary disease was associated with hyperparathyroidism in 90%. of cases, with enteropancreatic tumors in 47%, with adrenal tumors in 16%, and with thoracic neuroendocrine tumors in 4%. Pituitary disease was the initial lesion of MEN1 in 17% of all MEN1 patients. MEN1 pituitary adenomas were significantly more frequent in women than in men (50% vs. 31%,P < 0.001). Among the 136 pituitary adenomas, there were 85 prolactinomas and 12 GH-secreting, 6 ACTH-secreting, 13 cosecreting, and 20 nonsecreting tumors. Eighty-five percent of MEN1-related pituitary lesions were macroadenomas (vs. 42% in non-MEN1 patients, P < 0.001), including 32% of invasive cases. Among secreting adenomas, hormonal hypersecretion was normalized, after treatment, in only 42% (vs. 90% in non-MEN1 patients, P < 0.001), with a median follow-up of 11.4 yr. No correlation was found between the type of MEN1 germ-line mutation and the presence or absence of pituitary adenoma. Our study, based on a large group of MEN1 patients, shows that pituitary adenomas occur in 42% of the cases and are characterized by a larger size and a more aggressive presentation than without MEN1

First Results of Mg I (3p <SUP>1</SUP>P<SUB>1</SUB>-4d <SUP>1</SUP>D<SUB>2</SUB>) Line Linear Impact Polarization during the Solar Flare on 2001 June 15

International audienceThe results of the analysis of the first spectropolarimetric observations of the 3p 1P1-4d 1D2 Mg I line at 5528.4 Å made during a solar flare are presented in this paper. The line is found to be polarized with a polarization degree at the line center that reaches up to 3% and a direction of polarization nearly parallel to the local transverse magnetic field. After eliminating scattering, the Zeeman effect, and the intensity gradient as possible origins of the observed polarization, this polarization is interpreted as due either to a low-energy proton beam or to the return current associated with electron beams