982 resultados para Elliptic orbits


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Homogeneously reprocessed combined GPS/GLONASS 1- and 3-day solutions from 1994 to 2013, generated by the Center for Orbit Determination in Europe (CODE) in the frame of the second reprocessing campaign REPRO-2 of the International GNSS Service, as well as GPS- and GLONASS-only 1- and 3-day solutions for the years 2009 to 2011 are analyzed to assess the impact of the arc length on the estimated Earth Orientation Parameters (EOP, namely polar motion and length of day), on the geocenter, and on the orbits. The conventional CODE 3-day solutions assume continuity of orbits, polar motion components, and of other parameters at the day boundaries. An experimental 3-day solution, which assumes continuity of the orbits, but independence from day to day for all other parameters, as well as a non-overlapping 3-day solution, is included into our analysis. The time series of EOPs, geocenter coordinates, and orbit misclosures, are analyzed. The long-arc solutions were found to be superior to the 1-day solutions: the RMS values of EOP and geocenter series are typically reduced between 10 and 40 %, except for the polar motion rates, where RMS reductions by factors of 2–3 with respect to the 1-day solutions are achieved for the overlapping and the non-overlapping 3-day solutions. In the low-frequency part of the spectrum, the reduction is even more important. The better performance of the orbits of 3-day solutions with respect to 1-day solutions is also confirmed by the validation with satellite laser ranging.

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Context. The European Space Agency Rosetta mission reached and started escorting its main target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, at the beginning of August 2014. Within the context of solar system small bodies, satellite searches from approaching spacecraft were extensively used in the past to study the nature of the visited bodies and their collisional environment. Aims. During the approaching phase to the comet in July 2014, the OSIRIS instrument onboard Rosetta performed a campaign aimed at detecting objects in the vicinity of the comet nucleus and at measuring these objects' possible bound orbits. In addition to the scientific purpose, the search also focused on spacecraft security to avoid hazardous material in the comet's environment. Methods. Images in the red spectral domain were acquired with the OSIRIS Narrow Angle Camera, when the spacecraft was at a distance between 5785 km and 5463 km to the comet, following an observational strategy tailored to maximize the scientific outcome. From the acquired images, sources were extracted and displayed to search for plausible displacements of all sources from image to image. After stars were identified, the remaining sources were thoroughly analyzed. To place constraints on the expected displacements of a potential satellite, we performed Monte Carlo simulations on the apparent motion of potential satellites within the Hill sphere. Results. We found no unambiguous detections of objects larger than similar to 6 m within similar to 20 km and larger than similar to 1 m between similar to 20 km and similar to 110 km from the nucleus, using images with an exposure time of 0.14 s and 1.36 s, respectively. Our conclusions are consistent with independent works on dust grains in the comet coma and on boulders counting on the nucleus surface. Moreover, our analysis shows that the comet outburst detected at the end of April 2014 was not strong enough to eject large objects and to place them into a stable orbit around the nucleus. Our findings underline that it is highly unlikely that large objects survive for a long time around cometary nuclei.

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Aims. The OSIRIS camera onboard the Rosetta spacecraft has been acquiring images of the comet 67P/Churyumov-Gerasimenko (67P)'s nucleus at spatial resolutions down to similar to 0.17 m/px ever since Aug. 2014. These images have yielded unprecedented insight into the morphological diversity of the comet's surface. This paper presents an overview of the regional morphology of comet 67P. Methods. We used the images that were acquired at orbits similar to 20-30 km from the center of the comet to distinguish different regions on the surface and introduce the basic regional nomenclature adopted by all papers in this Rosetta special feature that address the comet's morphology and surface processes. We used anaglyphs to detect subtle regional and topographical boundaries and images from close orbit (similar to 10 km from the comet's center) to investigate the fine texture of the surface. Results. Nineteen regions have currently been defined on the nucleus based on morphological and/or structural boundaries, and they can be grouped into distinctive region types. Consolidated, fractured regions are the most common region type. Some of these regions enclose smooth units that appear to settle in gravitational sinks or topographically low areas. Both comet lobes have a significant portion of their surface covered by a dusty coating that appears to be recently placed and shows signs of mobilization by aeolian-like processes. The dusty coatings cover most of the regions on the surface but are notably absent from a couple of irregular large depressions that show sharp contacts with their surroundings and talus-like deposits in their interiors, which suggests that short-term explosive activity may play a significant role in shaping the comet's surface in addition to long-term sublimation loss. Finally, the presence of layered brittle units showing signs of mechanical failure predominantly in one of the comet's lobes can indicate a compositional heterogeneity between the two lobes.

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We describe radial-velocity time series obtained by HARPS on the 3.60 m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD -114672. Their periods range from 492 to 1684 days, semi-major axes range from 1.2 to 2.69 AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5 MJup. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663 ± 8 and 1818 ± 25 days, orbital eccentricities of 0.14 ± 0.08 and 0.20 ± 0.04, and minimum masses of 0.36 ± 0.04 and 0.93 ± 0.06 MJup. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557 ± 0.0001 days and a minimum mass of 0.62 ± 0.025 MJup. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet stars with typical 2 m s-1 radial velocity precision.

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Aims. We extend the results of planetary formation synthesis by computing the long-term evolution of synthetic systems from the clearing of the gas disk into the dynamical evolution phase. Methods. We use the symplectic integrator SyMBA to numerically integrate the orbits of planets for 100 Myr, using populations from previous studies as initial conditions. Results. We show that within the populations studied, mass and semimajor axis distributions experience only minor changes from post-formation evolution. We also show that, depending upon their initial distribution, planetary eccentricities can statistically increase or decrease as a result of gravitational interactions. We find that planetary masses and orbital spacings provided by planet formation models do not result in eccentricity distributions comparable to observed exoplanet eccentricities, requiring other phenomena, such as stellar fly-bys, to account for observed eccentricities.

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Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10(-10) to 10(-7) kilograms, and 48 grains of mass 10(-5) to 10(-2) kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 +/- 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.

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Asteroid 2008 TC3 (approximately 4m diameter) was tracked and studied in space for approximately 19h before it impacted Earth's atmosphere, shattering at 44-36km altitude. The recovered samples (>680 individual rocks) comprise the meteorite Almahata Sitta (AhS). Approximately 50-70% of these are ureilites (ultramafic achondrites). The rest are chondrites, mainly enstatite, ordinary, and Rumuruti types. The goal of this work is to understand how fragments of so many different types of parent bodies became mixed in the same asteroid. Almahata Sitta has been classified as a polymict ureilite with an anomalously high component of foreign clasts. However, we calculate that the mass of fallen material was 0.1% of the pre-atmospheric mass of the asteroid. Based on published data for the reflectance spectrum of the asteroid and laboratory spectra of the samples, we infer that the lost material was mostly ureilitic. Therefore, 2008 TC3 probably contained only a few percent nonureilitic materials, similar to other polymict ureilites except less well consolidated. From available data for the AhS meteorite fragments, we conclude that 2008 TC3 samples essentially the same range of types of ureilitic and nonureilitic materials as other polymict ureilites. We therefore suggest that the immediate parent of 2008 TC3 was the immediate parent of all ureilitic material sampled on Earth. We trace critical stages in the evolution of that material through solar system history. Based on various types of new modeling and re-evaluation of published data, we propose the following scenario. (1) The ureilite parent body (UPB) accreted 0.5-0.6Ma after formation of calcium-aluminum-rich inclusions (CAI), beyond the ice line (outer asteroid belt). Differentiation began approximately 1Ma after CAI. (2) The UPB was catastrophically disrupted by a major impact approximately 5Ma after CAI, with selective subsets of the fragments reassembling into daughter bodies. (3) Either the UPB (before breakup), or one of its daughters (after breakup), migrated to the inner belt due to scattering by massive embryos. (4) One daughter (after forming in or migrating to the inner belt) became the parent of 2008 TC3. It developed a regolith, mostly 3.8Ga ago. Clasts of enstatite, ordinary, and Rumuruti-type chondrites were implanted by low-velocity collisions. (5) Recently, the daughter was disrupted. Fragments were injected or drifted into Earth-crossing orbits. 2008 TC3 comes from outer layers of regolith, other polymict ureilites from deeper regolith, and main group ureilites from the interior of this body. In contrast to other models that have been proposed, this model invokes a stochastic history to explain the unique diversity of foreign materials in 2008 TC3 and other polymict ureilites.

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Esta tesis doctoral se inscribe dentro de la Traductología, interdisciplina que estudia tanto los procesos implicados en el complejo fenómeno de la traducción como los productos discursivos en la lengua hacia la cual se traduce. Su objetivo general consiste en contribuir a la investigación sobre el macroproceso de traducción en el par de lenguas francés/español, y en especial sobre la producción discursiva puesto que la literatura especializada coincide en destacar que ésta es la fase menos conocida [Lederer, 2005, 126; Toury, 2004, 244, 245]. Nuestro trabajo explora la producción discursiva, limitándola a traducciones absolutas [Gouadec, 1989: 21-30] de textos pragmáticos [Delisle, 1984: 22], cuya función esencial es el pasaje integral de la información. Dentro de dos corpora del campo de la Bioética constituidos por textos originales en francés y sus traducciones al castellano, hemos considerado como hipótesis general que los productos discursivos resultantes de la traducción absoluta de textos pragmáticos francés/castellano, presentan transferencias sintáctico-discursivas gobernadas por el universal de interferencia. Es decir que el planteo rector es que la memoria lingüístico-discursiva en la fase de reexpresión está atravesada por el mecanismo de interferencia. Las hipótesis específicas que se desgranan de la principal indican que la producción discursiva resultante de la traducción de textos pragmáticos francés/castellano exhibe enunciados elípticos anómalos gobernados por el universal de interferencia del discurso de partida [francés] o del sistema de la lengua materna del traductor [castellano]. Nuestra investigación parte entonces de la lectura del texto traducido [TT] y lo compara con el texto original [TO]; esta comparación es parcial puesto que indaga sobre las anomalías de producción; es indirecta pues observa la relación cohesión-coherencia-sentido en el discurso de llegada a través de las anomalías, especialmente de los enunciados elípticos; por último, analiza las anomalías dentro de la teoría de la interferencia y de la teoría de la elipsis [Toury, 2004: 121-124]. Sobre estas bases, hemos generado un instrumento que estudia los binomios textuales seleccionados según las siguientes aproximaciones: la sintaxis de la lengua meta [tipo de elipsis, elemento elidido, construcción de la elipsis, recuperabilidad]; la sintaxis del discurso meta [cohesión-coherencia], la comparación del binomio TT-TO [análisis de la producción del segmento problema en TO; el análisis de la producción del segmento solución en TT; posible extensión de las consecuencias de la anomalía microestructural; verificación del principio traducir toda la información]; los mecanismos de producción [elevación de la frecuencia de uso de recursos o elementos; control lingüístico de la lengua-cultura meta; control lingüístico-discursivo]; el resultado [visibilidad de interferencia; fenómeno sintáctico visible; alcance discursivo; producción palimpséstica; entropía informativa]. La elaboración de este andamiaje analítico aplicado a nuestros corpora nos ha permitido avanzar en el conocimiento de los mecanismos que participan en la producción discursiva en traducción y creemos que puede aplicarse, con las modificaciones de cada caso, para la descripción y quizás explicación de otros factores lingüístico-discursivos presentes en los textos traducidos

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Esta tesis doctoral se inscribe dentro de la Traductología, interdisciplina que estudia tanto los procesos implicados en el complejo fenómeno de la traducción como los productos discursivos en la lengua hacia la cual se traduce. Su objetivo general consiste en contribuir a la investigación sobre el macroproceso de traducción en el par de lenguas francés/español, y en especial sobre la producción discursiva puesto que la literatura especializada coincide en destacar que ésta es la fase menos conocida [Lederer, 2005, 126; Toury, 2004, 244, 245]. Nuestro trabajo explora la producción discursiva, limitándola a traducciones absolutas [Gouadec, 1989: 21-30] de textos pragmáticos [Delisle, 1984: 22], cuya función esencial es el pasaje integral de la información. Dentro de dos corpora del campo de la Bioética constituidos por textos originales en francés y sus traducciones al castellano, hemos considerado como hipótesis general que los productos discursivos resultantes de la traducción absoluta de textos pragmáticos francés/castellano, presentan transferencias sintáctico-discursivas gobernadas por el universal de interferencia. Es decir que el planteo rector es que la memoria lingüístico-discursiva en la fase de reexpresión está atravesada por el mecanismo de interferencia. Las hipótesis específicas que se desgranan de la principal indican que la producción discursiva resultante de la traducción de textos pragmáticos francés/castellano exhibe enunciados elípticos anómalos gobernados por el universal de interferencia del discurso de partida [francés] o del sistema de la lengua materna del traductor [castellano]. Nuestra investigación parte entonces de la lectura del texto traducido [TT] y lo compara con el texto original [TO]; esta comparación es parcial puesto que indaga sobre las anomalías de producción; es indirecta pues observa la relación cohesión-coherencia-sentido en el discurso de llegada a través de las anomalías, especialmente de los enunciados elípticos; por último, analiza las anomalías dentro de la teoría de la interferencia y de la teoría de la elipsis [Toury, 2004: 121-124]. Sobre estas bases, hemos generado un instrumento que estudia los binomios textuales seleccionados según las siguientes aproximaciones: la sintaxis de la lengua meta [tipo de elipsis, elemento elidido, construcción de la elipsis, recuperabilidad]; la sintaxis del discurso meta [cohesión-coherencia], la comparación del binomio TT-TO [análisis de la producción del segmento problema en TO; el análisis de la producción del segmento solución en TT; posible extensión de las consecuencias de la anomalía microestructural; verificación del principio traducir toda la información]; los mecanismos de producción [elevación de la frecuencia de uso de recursos o elementos; control lingüístico de la lengua-cultura meta; control lingüístico-discursivo]; el resultado [visibilidad de interferencia; fenómeno sintáctico visible; alcance discursivo; producción palimpséstica; entropía informativa]. La elaboración de este andamiaje analítico aplicado a nuestros corpora nos ha permitido avanzar en el conocimiento de los mecanismos que participan en la producción discursiva en traducción y creemos que puede aplicarse, con las modificaciones de cada caso, para la descripción y quizás explicación de otros factores lingüístico-discursivos presentes en los textos traducidos

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At least two transient events of extreme global warming occurred superimposed on the long-term latest Paleocene and early Eocene warming trend in the Paleocene-Eocene thermal maximum (PETM) (or ETM1 ~55.5 Ma) and the Elmo (or ETM2 ?53.6 Ma). Other than warmth, the best known PETM is characterized by (1) significant injection of 13C-depleted carbon into the ocean-atmosphere system, (2) deep-sea carbonate dissolution, (3) strong biotic responses, and (4) perturbations of the hydrological cycle. Documentation of the other documented and suspected "hyperthermals" is, as yet, insufficient to assess whether they are similar in nature to the PETM. Here we present and discuss biomagnetostratigraphic data and geochemical records across two lower Eocene successions deposited on a continental margin of the western Tethys: the Farra and Possagno sections in the Venetian pre-Alps. We recognize four negative carbon isotope excursions within chron C24. Three of these shifts correlate to known or suspected hyperthermals: the PETM, the Eocene thermal maximum 2 (~53.6 Ma), and the informally named "X event" (~52.5 Ma). The fourth excursion lies within a reverse subchron and occurred between the latter two. In the Farra section, the X event is marked by a ~0.6 per mil negative carbon isotope excursion and carbonate dissolution. Furthermore, the event exhibits responses among calcareous nannofossils, planktic foraminifera, and dinoflagellates that are similar to, though less intense than, those observed across the PETM. Sedimentological and quantitative micropaleontological data from the Farra section also suggest increased weathering and runoff as well as sea surface eutrophication during this event.

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Esta tesis doctoral se inscribe dentro de la Traductología, interdisciplina que estudia tanto los procesos implicados en el complejo fenómeno de la traducción como los productos discursivos en la lengua hacia la cual se traduce. Su objetivo general consiste en contribuir a la investigación sobre el macroproceso de traducción en el par de lenguas francés/español, y en especial sobre la producción discursiva puesto que la literatura especializada coincide en destacar que ésta es la fase menos conocida [Lederer, 2005, 126; Toury, 2004, 244, 245]. Nuestro trabajo explora la producción discursiva, limitándola a traducciones absolutas [Gouadec, 1989: 21-30] de textos pragmáticos [Delisle, 1984: 22], cuya función esencial es el pasaje integral de la información. Dentro de dos corpora del campo de la Bioética constituidos por textos originales en francés y sus traducciones al castellano, hemos considerado como hipótesis general que los productos discursivos resultantes de la traducción absoluta de textos pragmáticos francés/castellano, presentan transferencias sintáctico-discursivas gobernadas por el universal de interferencia. Es decir que el planteo rector es que la memoria lingüístico-discursiva en la fase de reexpresión está atravesada por el mecanismo de interferencia. Las hipótesis específicas que se desgranan de la principal indican que la producción discursiva resultante de la traducción de textos pragmáticos francés/castellano exhibe enunciados elípticos anómalos gobernados por el universal de interferencia del discurso de partida [francés] o del sistema de la lengua materna del traductor [castellano]. Nuestra investigación parte entonces de la lectura del texto traducido [TT] y lo compara con el texto original [TO]; esta comparación es parcial puesto que indaga sobre las anomalías de producción; es indirecta pues observa la relación cohesión-coherencia-sentido en el discurso de llegada a través de las anomalías, especialmente de los enunciados elípticos; por último, analiza las anomalías dentro de la teoría de la interferencia y de la teoría de la elipsis [Toury, 2004: 121-124]. Sobre estas bases, hemos generado un instrumento que estudia los binomios textuales seleccionados según las siguientes aproximaciones: la sintaxis de la lengua meta [tipo de elipsis, elemento elidido, construcción de la elipsis, recuperabilidad]; la sintaxis del discurso meta [cohesión-coherencia], la comparación del binomio TT-TO [análisis de la producción del segmento problema en TO; el análisis de la producción del segmento solución en TT; posible extensión de las consecuencias de la anomalía microestructural; verificación del principio traducir toda la información]; los mecanismos de producción [elevación de la frecuencia de uso de recursos o elementos; control lingüístico de la lengua-cultura meta; control lingüístico-discursivo]; el resultado [visibilidad de interferencia; fenómeno sintáctico visible; alcance discursivo; producción palimpséstica; entropía informativa]. La elaboración de este andamiaje analítico aplicado a nuestros corpora nos ha permitido avanzar en el conocimiento de los mecanismos que participan en la producción discursiva en traducción y creemos que puede aplicarse, con las modificaciones de cada caso, para la descripción y quizás explicación de otros factores lingüístico-discursivos presentes en los textos traducidos

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Throughout the history of the Solar System, Earth has been bombarded by interplanetary dust particles (IDPs), which are asteroid and comet fragments of diameter 1-1,000 µm. The IDP flux is believed to be in quasi-steady state: particles created by episodic main belt collisions or cometary fragmentation replace those removed by comminution, dynamical ejection, and planetary or solar impact. Because IDPs are rich in 3He, seafloor sediment 3He concentrations provide a unique means of probing the major events that have affected the IDP flux and its source bodies over geological timescales (Farley et al., 1998, doi:10.1126/science.280.5367.1250; Takayanagi and Ozima, 1987, doi:10.1029/JB092iB12p12531; Farley, 1995, doi:10.1038/376153a0; Kortenkamp and Dermott, 1998, doi:10.1126/science.280.5365.874). Here we report that collisional disruption of the >150-km-diameter asteroid that created the Veritas family 8.3 +/- 0.5 Myr ago (Nesvorny et al., 2003, doi:10.1086/374807) also produced a transient increase in the flux of interplanetary dust-derived 3He. The increase began at 8.2 +/- 0.1 Myr ago, reached a maximum of 4 times pre-event levels, and dissipated over 1.5 Myr. The terrestrial IDP accretion rate was overwhelmingly dominated by Veritas family fragments during the late Miocene. No other event of this magnitude over the past 10**8 yr has been deduced from main belt asteroid orbits. One remarkably similar event is present in the 3He record 35 Myr ago, but its origin by comet shower (Farley et al., 1998, doi:10.1126/science.280.5367.1250) or asteroid collision (Tagle and Claeys, 2004, doi:10.1126/science.1098481) remains uncertain.

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The high-altitude lake Tso Moriri (32°55'46'' N, 78°19'24'' E; 4522 m a.s.l.) is situated at the margin of the ISM and westerly influences in the Trans-Himalayan region of Ladakh. Human settlements are rare and domestic and wild animals are concentrating at the alpine meadows. A set of modern surface samples and fossil pollen from deep-water TMD core was evaluated with a focus on indicator types revealing human impact, grazing activities and lake system development during the last ca. 12 cal ka BP. Furthermore, the non-pollen palynomorph (NPP) record, comprising remains of limnic algae and invertebrates as well as fungal spores and charred plant tissue fragments, were examined in order to attest palaeolimnic phases and human impact, respectively. Changes in the early and middle Holocene limnic environment are mainly influenced by regional climatic conditions and glacier-fed meltwater flow in the catchment area. The NPP record indicates low lake productivity with high influx of freshwater between ca. 11.5 and 4.5 cal ka BP which is in agreement with the regional monsoon dynamics and published climate reconstructions. Geomorphologic observations suggest that during this period of enhanced precipitation the lake had a regular outflow and contributed large amounts of water to the Sutlej River, the lower reaches of which were integral part of the Indus Civilization area. The inferred minimum fresh water input and maximum lake productivity between ca. 4.5-1.8 cal ka BP coincides with the reconstruction of greatest aridity and glaciation in the Korzong valley resulting in significantly reduced or even ceased outflow. We suggest that lowered lake levels and river discharge on a larger regional scale may have caused irrigation problems and harvest losses in the Indus valley and lowlands occupied by sedentary agricultural communities. This scenario, in turn, supports the theory that, Mature Harappan urbanism (ca. 4.5-3.9 cal ka BP) emerged in order to facilitate storage, protection, administration, and redistribution of crop yields and secondly, the eventual collapse of the Harappan Culture (ca. 3.5-3 cal ka BP) was promoted by prolonged aridity. There is no clear evidence for human impact around Tso Moriri prior to ca. 3.7 cal ka BP, with a more distinct record since ca. 2.7 cal ka BP. This suggests that the sedimentary record from Tso Moriri primarily archives the regional climate history.

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Physiognomic traits of plant leaves such as size, shape or margin are decisively affected by the prevailing environmental conditions of the plant habitat. On the other hand, if a relationship between environment and leaf physiognomy can be shown to exist, vegetation represents a proxy for environmental conditions. This study investigates the relationship between physiognomic traits of leaves from European hardwood vegetation and environmental parameters in order to create a calibration dataset based on high resolution grid cell data. The leaf data are obtained from synthetic chorologic floras, the environmental data comprise climatic and ecologic data. The high resolution of the data allows for a detailed analysis of the spatial dependencies between the investigated parameters. The comparison of environmental parameters and leaf physiognomic characters reveals a clear correlation between temperature related parameters (e.g. mean annual temperature or ground frost frequency) and the expression of leaf characters (e.g. the type of leaf margin or the base of the lamina). Precipitation related parameters (e.g. mean annual precipitation), however, show no correlation with the leaf physiognomic composition of the vegetation. On the basis of these results, transfer functions for several environmental parameters are calculated from the leaf physiognomic composition of the extant vegetation. In a next step, a cluster analysis is applied to the dataset in order to identify "leaf physiognomic communities". Several of these are distinguished, characterised and subsequently used for vegetation classification. Concerning the leaf physiognomic diversity there are precise differences between each of these "leaf physiognomic classes". There is a clear increase of leaf physiognomic diversity with increasing variability of the environmental parameters: Northern vegetation types are characterised by a more or less homogeneous leaf physiognomic composition whereas southern vegetation types like the Mediterranean vegetation show a considerable higher leaf physiognomic diversity. Finally, the transfer functions are used to estimate palaeo-environmental parameters of three fossil European leaf assemblages from Late Oligocene and Middle Miocene. The results are compared with results obtained from other palaeo-environmental reconstructing methods. The estimates based on a direct linear ordination seem to be the most realistic ones, as they are highly consistent with the Coexistence Approach.

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In this Comment we explain the discrepancies mentioned by the authors between their results and ours about the in?uence of the gravitational quadrupole moment in the perturbative calculation of corrections to the precession of the periastron of quasielliptical Keplerian equatorial orbits around a point mass. The discrepancy appears to be a consequence of two different calculations of the angular momentum of the orbits.