Search results for "Venus"

Using the transit of Venus to probe the upper planetary atmosphere

2015

The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus duri…

Data from: Plant – herbivorous beetle networks: molecular characterization of trophic ecology within a threatened steppic environment

2015

DNA barcoding facilitates many evolutionary and ecological studies, including the examination of the dietary diversity of herbivores. In this study, we present a survey of ecological associations between herbivorous beetles and host plants from seriously threatened European steppic grasslands. We determined host plants for the majority (65%) of steppic leaf beetles (55 species) and weevils (59) known from central Europe using two barcodes (trnL and rbcL) and two sequencing strategies (Sanger for mono/oligophagous species and Illumina for polyphagous taxa). To better understand the ecological associations between steppic beetles and their host plants, we tested the hypothesis that leaf beetl…

Determination of mercury, cadmium, chromium and lead in marine organisms by flameless atomic absorption spectrophotometry

1986

Iron Mineralogy of Venus' Surface Investigated by M�ssbauer Spectroscopy

2000

Abstract We discuss the use of Mossbauer (MB) spectroscopy to study Fe-bearing minerals on Venus' surface. At present, there is no direct information about the mineralogy of Venus' surface, although in situ chemical analyses by X-ray fluorescence (XRF) spectroscopy have been done by the Venera 13, 14, and Vega 2 spacecraft at three landing sites. The XRF elemental analyses are sensitive to major rock-forming elements heavier than sodium and show the presence of several mass percent iron. Normative mineralogical calculations model the Fe mineralogy at the Venera 13, 14, and Vega 2 landing sites, but the actual Fe minerals present are unknown. We calculate synthetic MB spectra for the normati…

2015

The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.e. by a change in the membrane potential (as in Venus flytrap), or purely mechanically. In the present study, electrophysiological experiments are conducted to clarify the mechanism. Artificial release experiments (chemical and electrical) and electrophysiological measurements were conducted with two phylogenetically distant species, Goeppertia bachemiana (E. Morren) Borchs. & S. Suarez and Donax cannif…

Rémunérer les médecins généralistes : la question des revenus

2010

National audience;

Action potentials induce biomagnetic fields in Venus flytrap plants

2020

Upon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electrophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. In the plant kingdom, two types of electrical signals are observed: all-or-nothing APs of similar amplitudes to those seen in humans and animals, and slow-wave potentials of smaller amplitud…

Recovering evidence for the use of marble and coloured limestone in the first century AD in excavations at the sanctuary of Venus at Pompeii.

2008

Trabajo feminino y distribucion de rentas en Espana

1988

International audience; En este artículo detallamos la actividad profesional de las mujeres casadas, y medimos, a lo largo del ciclo de vida de los hogares, el impacto del trabajo femenino sobre la distribución de las rentas familiares. A continuación, confrontamos la situación de España con la de otros paises donde han podido efectuarse análisis similares ^Francia, Gran gretaña y Estados Unidos).

Corpi che contano. Prolegomeni per una teoria della materialità delle immagini

2022

Oggetto di questo saggio è un tipo di artefatti che ha avu- to in passato, ha ancora e avrà in futuro un significato centra- le nella produzione dell’Homo Sapiens: le miniature. Si tratta di oggetti che hanno accompagnato tutta la sua evoluzione e la cui datazione non ha smesso di sorprendere i paleontologi. Sappiamo, ad esempio, che la scultura antropomorfa ritro- vata a Berekhat Ram (fig. 1) in Israele e quella di Tan Tan (fig. 2) in Marocco risalgono a parecchie centinaia di migliaia di anni fa, e dunque sono ben più antiche delle cosiddette Veneri che popolano il Paleolitico superiore europeo. The subject of this essay is a type of artifact that has had in the past, still has and will h…