The Spin Axis Position of C/1995 O1 (Hale–Bopp)

Monitoring of the near-nucleus activity of C/1995 O1 (Hale-Bopp) began in Teide Observatory in August 1995. During 1996 the comet was observed on 72 nights between March 26 and November 13. A permanent fan structure was observed towards the north during the whole period of observation. The position angle of the axis of this fan was measured and its variations with time were used to determine the position of the North Pole of the cometary nucleus. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ergebnisse der pflanzenphänologischen Forschung in Ungarn

Zusammenfassung Seit mehr als 110 Jahren werden in Ungarn systematische pflanzenphänologische Beobachtungen durchgeführt. Da die überwiegende Mehrheit der phänologischen Arbeiten nur in ungarischer Sprache erschienen ist, soll hier ein Überblick über das vorhandene Beobachtungsmaterial und über die Ergebnisse der pflanzenphänologischen Forschung in Ungarn geboten werden. Es sollen dabei nur die wichtigeren Publikationen über Pflanzenphänologie und ihre Grenzgebiete angeführt, ihre Ergebnisse bewertet und die Quellen bezeichnet werden, die Beobachtungsmaterial zur weiteren Bearbeitung und Forschung liefern.

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Summary Since more than 110 years systematic plant-phenological observations are made in Hungary. As the overwhelming majority of the phenological papers has been published in Hungarian language a survey over the existing data and over the results of the plant-phenological research in Hungary shall be given here. Only the more important publications on the subject of plant-phenology and its border areas are cited here. Their results are discussed and the sources are specified where one can find observational data for further work and research.

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Résumé On effectue depuis plus de 110 ans des observations phénologiques systématiques en Hongrie. Vu que la grande majorité des travaux effectués en phénologie ont été publiés en hongrois, on donne ici un aperçu du materiel d'observation existant et des résultats des recherches effectuées dans ce domaine en Hongrie. On n'a indiqué que les publications principales en phénologie et sciences connexes. On discute en outre les résultats obtenus et on en indique les sources qui pourraient fournir du matériel pour de nouvelles études et recherches.

     

Infall of gas in galaxies and triggered star formation

While the importance of merging, accretion, and infall processesin determining galactic evolution is well established boththeoretically and observationally, details on how such processesare taking place nowadays even in our own Galaxy are stillrelatively poorly known, especially due to large remaininguncertainties on the location and origin of high velocity clouds.In this paper we focus on the possible role that galacticoutflows and gas infall may have on directly triggering starformation in the halo and in galactic disks. While compellingevidence has been accumulating in recent years suggesting thatsome level of star formation directly triggered by outflows isvery likely to exist in the halo of some galaxies, the evidencefor star formation dynamically triggered by infall is far moreelusive due to confusion with other, more efficient large-scalestar forming mechanisms operating in the galactic disk. Despite ofincreasingly realistic simulations of the gas circulation betwenthe gas and the halo and of high velocity cloud impacts ongalactic disks, the efficiency of star formation directlytriggered by such impacts remains an open question.     

Hydrogeochemical and isotopic characterizations of an aquifer in the semi-arid region of the Mexican Highlands

This work addresses hydrogeochemical processes in shallow aquifers, represented by the Quaternary alluvial deposits, from a part of the semi-arid Mexican Highlands through the evaluations of physicochemical parameters as well as the δ¹⁸O and δ²H compositions of groundwater. Mifflin diagram separates the Na-bicarbonate, sulphate and mixed groundwater into one group showing interactions with volcanic lithology in the recharge zones and another group interacting with the evaporite rich sedimentary formation. In the Gibbs diagram, the samples with Cl^?/(Cl^? + HCO₃^?) < 0.4 showed higher influence of ion exchange and the samples with Cl^?/(Cl^? + HCO₃^?) > 0.4 showed higher effects of evaporation. All of them were oversaturated with carbonate minerals (i.e., calcite and dolomite) and unsaturated with evaporites (i.e., gypsum and halite). Evaporation (earlier stage) occurred before the water-rock interactions (later stage). Evolution occurs through three different routes such as up to 7.5‰ enrichment in δ¹⁸O caused by the infiltration with a certain delay and subsequently, the water-rock interaction became dominant. Ternary mixing models revealed dominant influence of local recharge (C₁) on the water system, contributing 70.4%. Water-rock interaction (C₃) with 18% and evaporation (C₂) with 11.6% had comparatively less influences. The presence of nitrate (2–60 mg/L) in the groundwater indicated variable degrees of anthropogenic pollution.     

Undrained instability detection under general stress conditions

Acta Geotechnica - This work proposes a criterion for the detection of undrained instability under multiaxial stress conditions at elemental level. To do so, it develops the application of the...     

Contaminant Spill in a Sandbox with Non-Gaussian Conductivities: Simultaneous Identification by the Restart Normal-Score Ensemble Kalman Filter

Mathematical Geosciences - The joint identification of the parameters defining a contaminant source and the heterogeneous distribution of the hydraulic conductivities of the aquifer where the...     

THERMAP: a mid-infrared spectro-imager for space missions to small bodies in the inner solar system

We present THERMAP, a mid-infrared spectro-imager for space missions to small bodies in the inner solar system, developed in the framework of the MarcoPolo-R asteroid sample return mission. THERMAP is very well suited to characterize the surface thermal environment of a NEO and to map its surface composition. The instrument has two channels, one for imaging and one for spectroscopy: it is both a thermal camera with full 2D imaging capabilities and a slit spectrometer. THERMAP takes advantage of the recent technological developments of uncooled microbolometer arrays, sensitive in the mid-infrared spectral range. THERMAP can acquire thermal images (8–18 μm) of the surface and perform absolute temperature measurements with a precision better than 3.5 K above 200 K. THERMAP can acquire mid-infrared spectra (8–16 μm) of the surface with a spectral resolution Δλ of 0.3 μm. For surface temperatures above 350 K, spectra have a signal-to-noise ratio >60 in the spectral range 9–13 μm where most emission features occur.     

ChemiX: a Bragg crystal spectrometer for the <Emphasis Type="Italic">Interhelioprobe</Emphasis> interplanetary mission

Interhelioprobe (IHP), an analogue to the ESA Solar Orbiter, is the prospective Russian space solar observatory intended for in-situ and remote sensing investigations of the Sun and the inner heliosphere from a heliocentric orbit with the perihelion of about 60 solar radii. One of several instruments on board will be the Bragg crystal spectrometer ChemiX which will measure X-ray spectra from solar corona structures. Analysis of the spectra will allow the determination of the elemental composition of plasma in hot coronal sources like flares and active regions. ChemiX is under development at the Wroc?aw Solar Physics Division of the Polish Academy of Sciences Space Research Centre in collaboration with an international team (see the co-author list). This paper gives an overview of the ChemiX scientific goals and design preparatory to phase B of the instrument development.