413 research outputs found
Impact of the European Russia drought in 2010 on the Caspian Sea level
This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2011 Arpe et al.The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.This article is a contribution to the European project Marie Curie, CLIMSEAS â PIRSES-GA-2009-247512: âClimate Change and Inland Seas: Phenomena, 20 Feedback and Uncertainties. The Physical Science Basisâ
Une analyse lexicaliste des affixes pronominaux en français
Cet article considĂšre comme acquis que les pronoms faibles du français sont des affixes flexionnels morphologiquement attachĂ©s Ă une base verbale et introduit le terme affixe pronominal pour les dĂ©signer. Nous proposons une analyse syntaxique strictement lexicaliste, dans le cadre HPSG, des formes verbales flĂ©chies pour des affixes pronominaux objets. Cette analyse explique les propriĂ©tĂ©s spĂ©cifiques de ces formes verbales au niveau de la syntaxe de la phrase, notamment (i) lâimpossibilitĂ© dâun complĂ©ment plein si la forme verbale est flĂ©chie pour lâaffixe correspondant; (ii) le phĂ©nomĂšne des affixes pronominaux « non locaux », câest-Ă -dire les cas oĂč les affixes pronominaux nâapparaissent pas sur la base verbale dont ils sont des arguments sĂ©mantiques; (iii) les corrĂ©lations entre la syntaxe des dĂ©pendances qu- et des affixes pronominaux, notamment au niveau du flottement des quantificateurs. Nous faisons crucialement appel Ă une forme de composition de fonctions, qui permet Ă une tĂȘte exigeant normalement un complĂ©ment saturĂ© de se combiner avec un complĂ©ment non saturĂ© et avec les complĂ©ments exigĂ©s par celui-ci.This paper takes as its premise the idea that French weak pronouns are in fact morphologically attached inflectional affixes, and introduces the term pronominal affix for them. We propose a strictly lexicalist syntactic analysis for verbs inflected for object pronominal affixes, couched in the framework of HPSG. This analysis explains the special syntactic properties of these verb forms, especially (i) the impossibility of a full complement in the presence of the corresponding affix on the verb; (ii) the phenomenon of "non local" pronominal affixes, i.e. cases where the affixes do not appear on the verb of which they are semantic arguments; (iii) the correlations between the syntax of wh- dependencies and that of pronominal affixes specifically with respect to quantifier floating. We crucially rely on a form of function composition that allows a head which normally requires a saturated complement to combine with a non-saturated complemement and with those complements which the latter normally requires
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Process length variation in cysts of a dinoflagellate, Lingulodinium machaerophorum, in surface sediments: Investigating its potential as salinity proxy
âMany authors have contributed to writing this paper. Those listed in the metadata are: the main/contact author, the first listed author and Brunel University author(s). For a full list of the authors, please see the PDF version.âA biometrical analysis of the dinoflagellate cyst Lingulodinium machaerophorum (Deflandre and Cookson 1955) Wall, 1967 in 144 globally distributed surface sediment samples revealed that the average process length is related to summer salinity and temperature at a water depth of 30 m by the equation (salinity/temperature) = (0.078*average process length + 0.534) with RÂČ = 0.69. This relationship can be used to reconstruct palaeosalinities, albeit with caution. The particular ecological window can be associated with known distributions of the corresponding motile stage Lingulodinium polyedrum (Stein) Dodge, 1989. Confocal laser microscopy showed that the average process length is positively related to the average distance between process bases (RÂČ=0.78), and negatively related to the number of processes (RÂČ=0.65). These results document the existence of two end members in cyst formation: one with many short, densely distributed processes and one with a few, long, widely spaced processes, which can be respectively related to low and high salinity/temperature ratios. Obstruction during formation of the cysts causes anomalous distributions of the processes. From a biological perspective, processes function to facilitate sinking of the cysts through clustering
A late Pleistocene long pollen record from Lake Urmia, NW Iran
A palynological study based on two 100-m long cores from Lake Urmia in northwestern Iran provides a vegetation record spanning 200 ka, the longest pollen record for the continental interior of the Near East. During both penultimate and last glaciations, a steppe of Artemisia and Poaceae dominated the upland vegetation with a high proportion of Chenopodiaceae in both upland and lowland saline ecosystems. While Juniperus and deciduous Quercus trees were extremely rare and restricted to some refugia, Hippophaë rhamnoides constituted an important phanerophyte, particularly during the upper last glacial sediments. A pronounced expansion in Ephedra shrub-steppe occurred at the end of the penultimate late-glacial period but was followed by extreme aridity that favoured an Artemisia steppe. Very high lake levels, registered by both pollen and sedimentary markers, occurred during the middle of the last glaciation and upper part of the penultimate glaciation. The late-glacial to early Holocene transition is represented by a succession of Hippophaë, Ephedra, Betula, Pistacia and finally Juniperus and Quercus. The last interglacial period (Eemian), slightly warmer and moister than the Holocene, was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern European pollen sequences
THE INFLUENCE OF FIRING ORDER ON THE PERFORMANCE OF A HIGH SPEED MARINE DIESEL ENGINE
The paper describes a parametric study of the influence of firing order on the performance of a high speed marine diesel engine. A 16 cylinder, 4 valve per cylinder, direct injection, supercharged high speed marine diesel engine was considered for the study. Having inspected the firing order and the phase angles of the cylinders for the base engine case, theoretically possible firing orders were determined as parameters. The computer simulation program employed in the study utilises the Method of Characteristics for the unsteady gas flow in the exhaust and intake manifolds of the engine. In-cylinder calculations are coupled to the unsteady gas flow calculations and they include the gas exchange process and a combustion simulation routine by a heat release scheme. The turbocharger simulation is carried out by a subroutine and it appears as a boundary to the unsteady gas flow calculations. The results were
presented in the form of time-resolved graphs for the in-cylinder and intake pipe pressures for each parameter change. The calculated values of specific fuel consumption and power produced per cylinder for the test cases were compared
The Exozodiacal Dust Problem for Direct Observations of ExoEarths
Debris dust in the habitable zones of stars - otherwise known as exozodiacal
dust - comes from extrasolar asteroids and comets and is thus an expected part
of a planetary system. Background flux from the Solar System's zodiacal dust
and the exozodiacal dust in the target system is likely to be the largest
source of astrophysical noise in direct observations of terrestrial planets in
the habitable zones of nearby stars. Furthermore, dust structures like clumps,
thought to be produced by dynamical interactions with exoplanets, are a
possible source of confusion. In this paper, we qualitatively assess the
primary impact of exozodical dust on high-contrast direct imaging at optical
wavelengths, such as would be performed with a coronagraph. Then we present the
sensitivity of previous, current, and near-term facilities to thermal emission
from debris dust at all distances from nearby solar-type stars, as well as our
current knowledge of dust levels from recent surveys. Finally, we address the
other method of detecting debris dust, through high-contrast imaging in
scattered light. This method is currently far less sensitive than thermal
emission observations, but provides high spatial resolution for studying dust
structures. This paper represents the first report of NASA's Exoplanet
Exploration Program Analysis Group (ExoPAG).Comment: 21 pages, 5 figures, 2 tables. Accepted for publication in PASP
2012-06-0
An early Little Ice Age brackish water invasion along the south coast of the Caspian Sea (sediment of Langarud wetland) and its wider impacts on environment and people
Caspian Sea level has undergone significant changes through time with major impacts not only on the surrounding coasts, but also offshore. This study reports a brackish water invasion on the southern coast of the Caspian Sea constructed from a multi-proxy analysis of sediment retrieved from the Langarud wetland. The ground surface level of wetland is >6 m higher than the current Caspian Sea level (at -27.41 m in 2014) and located >11 km far from the coast. A sequence covering the last millennium was dated by three radiocarbon dates. The results from this new study suggest that Caspian Sea level rose up to at least -21.44 m (i.e. >6 m above the present water level) during the early Little Ice Age. Although previous studies in the southern coast of the Caspian Sea have detected a high-stand during the Little Ice Age period, this study presents the first evidence that this high-stand reached so far inland and at such a high altitude. Moreover, it confirms one of the very few earlier estimates of a high-stand at -21 m for the second half of the 14th century. The effects of this large-scale brackish water invasion on soil properties would have caused severe disruption to regional agriculture, thereby destabilizing local dynasties and facilitating a rapid Turko-Mongol expansion of Tamerlaneâs armies from the east.N Ghasemi (INIOAS), V Jahani (Gilan Province Cultural Heritage and Tourism Organisation) and A Naqinezhad (University of Mazandaran), INQUA QuickLakeH project (no. 1227) and to the European project Marie Curie, CLIMSEAS-PIRSES-GA-2009-24751
Usage Pattern Recognition in Student Activities
Proceedings of: 6th European Conference of Technology Enhanced Learning, EC-TEL 2011, Palermo, Italy, September 20-23, 2011.This paper presents an approach of collecting contextualized attention metadata combined from inside as well as outside a LMS and analyzing them to create feedback about the student activities for the teaching staff. Two types of analyses were run on the collected data: first, key actions were extracted to identify usage patterns and tendencies throughout the whole course and then usage statistics and patterns were identified for some key actions in more detail. Results of both analyses were visualized and presented to the teaching staff for evaluation.The research leading to these results has received funding
from the European Communityâs Seventh Framework Programme (FP7/2007-
2013) under grant agreement no 231396 (ROLE project). Work was also partially
funded by the Learn3 project (TIN2008-05163/TSI), the eMadrid project
(S2009/TIC-1650), and the AcciĂłn Integrada DE2009-0051
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