The prompt penetration of the interplanetary electric field to the equatorial ionosphere is conveniently modeled with a frequency‐dependent transfer function. However, long‐period responses (>3 h) of previously estimated transfer functions differ considerably due to insufficient ionospheric eastward electric field (EEF) data useful for spectral analysis. The EEF derived from the Challenging Minisatellite Payload (CHAMP) satellite provides a new opportunity to reliably estimate the long‐period transfer function for the first time. Our objectives in this paper are twofold: first, we analyze the frequency spectra of the equatorial ionospheric eastward electric field for periods greater than 6 h; second, we test the hypothesis that the average prompt‐penetration effect lasts less than 3 h after an initial perturbation in the interplanetary electric field (IEF). We find that atm...

The daytime eastward equatorial electric field (EEF) in the ionospheric E‐region plays an important role in equatorial ionospheric dynamics. It is responsible for driving the equatorial electrojet (EEJ) current system, equatorial vertical ion drifts, and the equatorial ionization anomaly. Due to its importance, there is much interest in accurately measuring and modeling the EEF. In this work we propose a method of estimating the EEF using CHAMP satellite‐derived latitudinal current profiles of the daytime EEJ along with Δ H measurements from ground magnetometer stations. Magnetometer station pairs in both Africa and South America were used for this study to produce time series of electrojet current profiles. These current profiles were then inverted for estimates of the EEF by solving the governing electrostatic equations. We compare our results with the Ion Velocity Meter (IVM) i...

Este documento investiga la relación entre la estructura de propiedad y el directorio con el valor de la empresa. La muestra consiste en un panel de 85 empresas chilenas no financieras para el periodo 2006-2013. Los resultados son consistentes con investigaciones previas para el caso chileno. La estructura de propiedad y la pertenencia a un grupo económico tienen influencia en el valor de la empresa. Los resultados del análisis econométrico evidencian una relación negativa entre estructura de propiedad y valor de empresa, sin embargo existe una relación positiva cuando la firma es parte de un grupo económico y aumenta en el tamaño del directorio, ambos resultados son estadísticamente significativos.

Este documento investiga la relación entre la estructura de propiedad y el directorio con el valor de la empresa. La muestra consiste en un panel de 85 empresas chilenas no financieras para el periodo 2006-2013. Los resultados son consistentes con investigaciones previas para el caso chileno. La estructura de propiedad y la pertenencia a un grupo económico tienen influencia en el valor de la empresa. Los resultados del análisis econométrico evidencian una relación negativa entre estructura de propiedad y valor de empresa, sin embargo existe una relación positiva cuando la firma es parte de un grupo económico y aumenta en el tamaño del directorio, ambos resultados son estadísticamente significativos.

Este documento investiga la relación entre la estructura de propiedad y el directorio con el valor de la empresa. La muestra consiste en un panel de 85 empresas chilenas no financieras para el periodo 2006-2013. Los resultados son consistentes con investigaciones previas para el caso chileno. La estructura de propiedad y la pertenencia a un grupo económico tienen influencia en el valor de la empresa. Los resultados del análisis econométrico evidencian una relación negativa entre estructura de propiedad y valor de empresa, sin embargo existe una relación positiva cuando la firma es parte de un grupo económico y aumenta en el tamaño del directorio, ambos resultados son estadísticamente significativos.

The eastward equatorial electric field (EEF) in the E region ionosphere drives many important phenomena at low latitudes. We developed a method of estimating the EEF from magnetometer measurements of near‐polar orbiting satellites as they cross the magnetic equator, by recovering a clean signal of the equatorial electrojet current and modeling the observed current to determine the electric field present during the satellite pass. This algorithm is now implemented as an official Level‐2 Swarm product. Here we present first results of EEF estimates from nearly a year of Swarm data. We find excellent agreement with independent measurements from the ground‐based coherent scatter radar at Jicamarca, Peru, as well as horizontal field measurements from the West African Magnetometer Network magnetic observatory chain. We also calculate longitudinal gradients of EEF measurements made by the...

As global copper demand surges, it's vital to conduct a thorough analysis of metal concentrations in the agricultural soils of mining districts. This is especially pertinent for the Andean region, where, in the face of clear soil degradation, there's a notable lack of in-depth research. This study is the first attempt to characterize variations in the concentration of 17 metals in the agricultural soils of Moquegua – a region with a long history of mining activity that contributes significantly to Peru's position as the world's second-largest producer of copper. The surface horizons of 336 agricultural soils under vegetable crops were sampled between 9 and 3,934 m above sea level (m.a.s.l.) to determine the total content of metal nutrients (MNs) (Ca, Mg, K, Na, Fe, Cu, Mn, Zn) and heavy metals (HMs) (Cd, Cr, Ni, Pb, As, Co, Ba, V, Al) by inductively coupled plasma-optical emission spec...

As global copper demand surges, it's vital to conduct a thorough analysis of metal concentrations in the agricultural soils of mining districts. This is especially pertinent for the Andean region, where, in the face of clear soil degradation, there's a notable lack of in-depth research. This study is the first attempt to characterize variations in the concentration of 17 metals in the agricultural soils of Moquegua – a region with a long history of mining activity that contributes significantly to Peru's position as the world's second-largest producer of copper. The surface horizons of 336 agricultural soils under vegetable crops were sampled between 9 and 3,934 m above sea level (m.a.s.l.) to determine the total content of metal nutrients (MNs) (Ca, Mg, K, Na, Fe, Cu, Mn, Zn) and heavy metals (HMs) (Cd, Cr, Ni, Pb, As, Co, Ba, V, Al) by inductively coupled plasma-optical emission spec...