Midlatitude propagation of VLF to MF waves through nighttime ionosphere above powerful VLF transmitters

International audience[1] Midlatitude nighttime observations made by the DEMETER satellite in the very low frequency (VLF) to medium frequency (MF) bands (3 kHz to 3 MHz) have demonstrated the propagation of radio waves from the bottom of ionosphere up to the satellite altitude (~700 km). Propagation characteristics derived from the magneto-ionic theory [Budden, 1985] are used to explain the absence of wave observations between ~1 and 2 MHz. Under hypotheses made for the Appleton and Hartree (or Appleton and Lassen) formula, studies of the vertical variations of the real and imaginary parts of the refractive index are performed to point out modifications in the propagation characteristics of the waves: (i) at the crossing of the plasma cutoffs regions, (ii) at the crossing of the ordinary and extraordinary mode resonance regions, and (iii) in the region where the product of the collision frequency (n) and the electronic density (Ne) is maximum. It is shown that enhancements in the collision frequencies, produced by powerful VLF transmitters in the region where the product of n and Ne is maximum, open the half angle of the MF wave transmission cones and increase the power densities of those waves at the DEMETER altitude. Citation: Lefeuvre F., J. L. Pinc¸n , and M. Parrot (2013), Midlatitude propagation of VLF to MF waves through nighttime ionosphere above powerful VLF transmitters

TARANIS — Scientific payload and mission strategy

International audienceOn December 2010 the implementation phase of the TARANIS micro-satellite was authorized by the French space agency. TARANIS is dedicated to the study of impulsive transfers of energy between the Earth atmosphere and the space environment, and more precisely to the physics of the Transient Luminous Events (TLEs) and of the Terrestrial Gamma ray Flashes (TGFs). By 2015 TARANIS will provide combined Nadir observations of TLEs and TGFs, high resolution measurements of energetic electrons, and wave field measurements. The strategy adopted to maximize the scientific return of the data is presented

Temporal and spatial analyses on seismo-electric anomalies associated with the 27 February 2010 M = 8.8 Chile earthquake observed by DEMETER satellite

International audienceThis paper studies seismo-electromagnetic anomalies observed by the French satellite DEMETER (Detection of ElectroMagnetic Emissions Transmitted from Earthquake Regions) during the 27 February 2010 M = 8.8 Chile earthquake. The nighttime electron density (N e), electron temperature (T e), ion density (N i), ion temperature (T i) and whistler counts (C w) are investigated. A statistical analysis of the box-and-whisker method is applied to see if data of two or more groups under study are significantly different. A cross-examination of temporal variations before and after shows that N e and N i (C w) increases (decreases) appear 10–20 days before the earthquake. A comparison of data over the epicenter and those over its reference area can be employed to discriminate the earthquake-related anomalies from global effects. Results prove that anomalous enhancements of N e , N i , and T i occur specifically around the epicenter area. The intersection of the temporal and spatial results confirms that N e and N i are useful and sensitive detecting anomalous related to the 2010 M = 8.8 Chile earthquake

Perbedaan Asupan Lemak, Lingkar Pinggang dan Persentase Lemak Tubuh pada Wanita Dislipidemia dan Non Dislipidemia

Differences of fat intake, waist circumference and percentage of bodt fat in dyslipidemia and non dyslipidemia adult women: Heart disease is the leading cause of death in several countries in the world . One of the major risk factors for heart disease is dyslipidemia . Dyslipidemia is a disorder of lipid metabolism characterized by an increase or decrease in plasma lipid fractions . Dyslipidemia has a strong relationship with the occurrence of central obesity . The purpose of this study was to analyze differences in the intake of fat , waist circumference and body fat percentage in dyslipidemia and non dyslipidemia adult women. This research is analytic study with cross sectional approach . The population in this study were adult women who examined their lipid profile in December 2013 in the Clinical Laboratory Cito Indraprasta Semarang . The total sample was 32 people . Independent test analysis of the differences using t-test for variables waist circumference and Mann Whitney test for variable fat intake and body fat percentage to 95 % and a significance level of 5% error. The results showed 17 adult women ( 53.1 % ) and 15 female adult dyslipidemia ( 46.9 % ) non- dyslipidemia. Average intake of fat, waist circumference and percentage body fat in adult women dyslipidemia higher than non dyslipidemia in adult women. Analysis of statistical tests showed difference in fat intake , waist circumference and body fat percentage in women adult dyslipidemia and non dyslipidemia (p value, respectively p = 0.002, p = 0.0001 and p = 0.0001

Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking

The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS, http://gnps.ucsd.edu), an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data

Is There an Earthquake Weather?

International audienceThe aim of this study is to check if there is a relationship between the seismic activity and the whistlers observed by the micro-satellite DEMETER. Whistlers are the waves emitted by lightning strokes during thunderstorm activity. They use to propagate in the Earth-ionosphere waveguide but also in the ionosphere and the magnetosphere mainly along the magnetic field lines. Due to this reason we have checked the whistler occurrence not close to earthquake epicenters but close to the magnetically conjugate point of these epicenters at the satellite altitude. The number of whistlers is given by a neural network in operation onboard the satellite. It appears that the whistler amplitude is attenuated at the satellite altitude around the magnetic equator. It is why we have removed the earthquakes occurring at low geomagnetic latitudes in the statistic. The whistler rate is normalized with a background value to take into account the seasons and the epicenter locations. A superposed epoch method is used to display the results between −15 and +5 days around the earthquake day and up to 1000 km from the conjugate point of the epicenters. It is shown that the whistler rate is higher the day before the earthquake at a distance less than 200 km. It would be unrealistic to believe in the possibility to use this study for earthquake prediction because everyday thunderstorm activity reliably masks seismic effects. But it is further evidence that there is a lithosphere-atmosphere-ionosphere coupling at the time of the seismic activity

Variations of the main nighttime ionospheric density anomalies observed by DEMETER during the descending phase of solar cycle 23

International audienceThis paper is related to analysis of the Weddell Sea Anomaly (WSA) and the Mid-latitude Summer Nighttime Anomaly (MSNA) observed by the low altitude satellite DEMETER during nighttime between 2004 and 2010. This time interval corresponds to the decrease of the solar cycle 23 which was unusually long. It appears that, if these two anomalies have a peak in local summer (December in the Southern hemisphere for the WSA, June in the Northern hemisphere for the MSNA), the anomalies are also observed during the months around December and June with a decreased intensity. But at the end of the solar cycle 23 the summer peaks dramatically decrease and even relatively more quickly than the solar index F10.7. This phenomenon is much more significant for the WSA. It is shown that the mechanism producing the two anomalies (thermospheric neutral winds and magnetic declination effects) is strengthened by the solar ionization which is active during the night above the WSA and the MSNA areas. But at solar minimum, this mechanism is weakened. These results are valid at the satellite altitude (660 km) and may vary at lower altitudes

Petit manuel du paludisme : à l'usage des écoles primaires de l'Afrique du Nord : livre du maître / par le Dr L.-M. Parrot,... ; lettre-préface de A. Astier,...

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