Venus Express radio occultation observed by PRIDE

Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g., NASA's Deep Space Network (DSN), ESA's Estrack). Aims. We want to characterize the capabilities of the Planetary Radio Interferometry and Doppler Experiment (PRIDE) technique for radio occultation experiments, using radio telescopes equipped with Very Long Baseline Interferometry (VLBI) instrumentation. Methods. We conducted a test with ESA's Venus Express (VEX), to evaluate the performance of the PRIDE technique for this particular application. We explain in detail the data processing pipeline of radio occultation experiments with PRIDE, based on the collection of so-called open-loop Doppler data with VLBI stations, and perform an error propagation analysis of the technique. Results. With the VEX test case and the corresponding error analysis, we have demonstrated that the PRIDE setup and processing pipeline is suited for radio occultation experiments of planetary bodies. The noise budget of the open-loop Doppler data collected with PRIDE indicated that the uncertainties in the derived density and temperature profiles remain within the range of uncertainties reported in previous Venus' studies. Open-loop Doppler data can probe deeper layers of thick atmospheres, such as that of Venus, when compared to closed-loop Doppler data. Furthermore, PRIDE through the VLBI networks around the world, provides a wide coverage and range of large antenna dishes, that can be used for this type of experiments

Measurement of the 244^{244}Cm and 246^{246}Cm Neutron-Induced Cross Sections at the n_TOF Facility

The neutron capture reactions of the $^{244}$Cm and $^{246}$Cm isotopes open the path for the formation of heavier Cm isotopes and of heavier elements such as Bk and Cf in a nuclear reactor. In addition, both isotopes belong to the minor actinides with a large contribution to the decay heat and to the neutron emission in irradiated fuels proposed for the transmutation of nuclear waste and fast critical reactors. The available experimental data for both isotopes are very scarce. We measured the neutron capture cross section with isotopically enriched samples of $^{244}$Cm and $^{246}$Cm provided by JAEA. The measurement covers the range from 1 eV to 250 eV in the n_TOF Experimental Area 2 (EAR-2). In addition, a normalization measurement with the $^{244}$Cm sample was performed at Experimental Area 1 (EAR-1) with the Total Absorption Calorimeter (TAC)

Crise économique et évolution de l'emploi des jeunes citadins au Burkina Faso

Se basant sur les données d’une enquête biographique réalisée au Burkina Faso en 2000, cet article examine les changements dans l’activité économique des jeunes citadins au cours des 20 dernières années et l’influence de la détérioration du contexte socio-économique sur l’accès des jeunes au marché de l’emploi, avec un accent particulier sur les jeunes instruits et les femmes. L’analyse des histoires professionnelles montre une augmentation du chômage et une informalisation de l’emploi des jeunes Burkina Faso urbain. Cette étude met aussi clairement en évidence une rupture entre l’instruction et l’accès au secteur formel parmi les jeunes hommes, et l’instabilité croissante de l’emploi parmi les jeunes femmes

Deteriorating Economic Conditions and Changing Patterns of Youth Employment in Urban Burkina Faso: 1980-2000

Based on unique retrospective survey data collected in Burkina Faso in 2000, this article examines the changes that urban youth employment has undergone over the last 20 years and the impact of the changing socioeconomic context on young people's access to labor market, with particular reference to educated youth and young women. Analysis based on employment histories shows increasing unemployment and informalization of youth employment in urban Burkina Faso. The study also provides strong evidence of a rupture between education and modern sector employment among young men, and the increased instability of employment among young women

Caracterización de los agricultores, biodiversidad y tecnologías de cultivos en el consejo popular norte y sur del municipio de San José de las Lajas, provincia la Habana

Con la implementación del proyecto de fitomejoramiento participativo en la agricultura urbana, se ejecutó la primera fase de diagnóstico en el municipio de San José de las Lajas, con el objetivo de realizar un análisis de la diversidad existente en sus parcelas y patios, hacer la caracterización a los agricultores que forman parte de este proyecto y tener un conocimiento abarcador sobre las tecnologías de cultivos más aplicadas por ellos. El estudio pudo hacerse por medio de una encuesta con 13 preguntas y se entrevistaron 11 agricultores. Se pudo comprobar con la encuesta que existían agricultores representados de los diferentes niveles de estudios, aunque no se cuenta con universitarios y muchos son naturales de otras provincias. Sus principales cultivos son las hortalizas, viandas y frutas; sin embargo, presentan poco conocimiento de las variedades que siembran así como también es escasa la diversidad entre estos cultivos, debido a que la semilla mayormente la intercambian entre los mismos productores. Las tecnologías de cultivos pueden considerarse que aún son insuficientes, aunque se realiza una mejora del suelo con la utilización de productos orgánicos y biofertilizantes para su fertilidad, el control de plagas y enfermedades y uso de métodos de siembra. Esto nos muestra la necesidad de facilitarles a los campesinos nuevas variedades de los cultivos de su preferencia, de acuerdo con sus necesidades y condiciones, potenciando el empleo de las tecnologías adecuadas para el incremento de sus producciones

Genetic structure and heterozygosity-fitness correlation in young-of-the-year sole (Solea solea L.) inhabiting three contaminated West-European estuaries

Anthropogenic pressures in estuaries may impair not only the fitness of organisms and the evolutionary processes necessary to the survival, but also the management of exploited marine resources. In order to assess these impacts, phenotypic and genotypic data pertaining to young-of-the-year (YOY) sole (Solea solea) were screened in differentially contaminated North East Atlantic estuaries ranging from Portugal (Mondego) to the English Channel (Seine). YOY sole inhabiting each estuary was found being phenotypically distinct from each other; each of them being impacted by pollution when comparing observed phenotypic data with published literature. According to the strong pollution in the Seine estuary, the corresponding YOY sole sample showed significantly lower body mass, size and condition factor compared to other samples. Using fifteen genetic markers, the Mondego estuary demonstrated low, but significant levels of genetic differentiation with most of the samples. Using neutrality tests, two loci were found to be putatively under directional selection (Soso7 and Soso23), but only locus Soso7 demonstrated significant positive heterozygosity-fitness correlation (HFC) for body size and body mass, suggesting a possible ongoing adaptive process. The candidate locus MT associated to a detoxifying metallothionein gene did not show significant genetic differentiation, but (i) significant deficit in heterozygote in the Seine estuary as already reported in other coastal samples impacted by metallic contaminants, and (ii) significant positive HFC with body mass were found. Selective rather than demographic processes better explain an observed genetic structure in YOY sole and are predominantly associated with the heavily contaminated Seine estuary whose nursery function and capacity are degraded

Analysis of an Interplanetary Coronal Mass Ejection by a Spacecraft Radio Signal: A Case Study

Tracking radio communication signals from planetary spacecraft with ground-based telescopes offers the possibility to study the electron density and the interplanetary scintillation of the solar wind. Observations of the telemetry link of planetary spacecraft have been conducted regularly with ground antennae from the European Very Long Baseline Interferometry Network, aiming to study the propagation of radio signals in the solar wind at different solar elongations and distances from the Sun. We have analyzed the Mars Express spacecraft radio signal phase fluctuations while, based on a 3-D heliosphere plasma simulation, an interplanetary coronal mass ejection (ICME) crossed the radio path during one of our observations on 6 April 2015. Our measurements showed that the phase scintillation indices increased by a factor of 4 during the passage of the ICME. The method presented here confirms that the phase scintillation technique based on spacecraft signals provides information of the properties and propagation of the ICMEs in the heliosphere

Experimental neutron capture data of 58 Ni from the CERN n-TOF facility

The 58Ni(n,γ) cross section has been measured at the neutron time of flight facility n-TOF at CERN, in the energy range from 27 meV up to 400 keV. In total, 51 resonances have been analyzed up to 122 keV. Maxwellian averaged cross sections (MACS) have been calculated for stellar temperatures of kT=5-100 keV with uncertainties of less than 6%, showing fair agreement with recent experimental and evaluated data up to kT = 50 keV. The MACS extracted in the present work at 30 keV is 34.2±0.6stat±1.8sys mb, in agreement with latest results and evaluations, but 12% lower relative to the recent KADoNIS compilation of astrophysical cross sections. When included in models of the s-process nucleosynthesis in massive stars, this change results in a 60% increase of the abundance of 58Ni, with a negligible propagation on heavier isotopes. The reason is that, using both the old or the new MACS, 58Ni is efficiently depleted by neutron captures.Peer reviewe