New parametrization for differences between plasma kinetic codes

Validation and verification of plasma kinetics codes requires the development of quantitative methods and techniques for code comparisons. We describe two parameters that can be used for characterization of differences between such codes. It is shown that these parameters, which are determined from the most general results of kinetic codes, can provide important information on the differences between the basic rate coefficients employed. Application of this method is illustrated by comparisons of some results from the 3rd NLTE Code Comparison Workshop for carbon, germanium, and gold plasmas.Comment: Submitted to High Energy Density Physics, 12 pages, 2 figure

Pollenanalytical studies in NE-Nigeria: preliminary results from the Manga Grasslands and Lake Tilla, Biu Plateau

Two sites situated in the Sahelian and Sudanian zones of NE-Nigeria were chosen for pollen analysis. A sediment core from an interdunal depression in the eastern Manga Grassland provides information on the Holocene vegetation history of the Sahel between c. 9600-3400 B.P. The 3 m pollen record indicates an open savanna during the mid-Holocene. The presence of Sudano-Guinean taxa, which were mainly restricted to the interdunal depressions, points to more humid conditions. Already before c. 4000 B.P., a slow change towards drier conditions and the establishment of the modern Sahelian vegetation is visible in the diagram. This development was accompanied by high fire frequencies. A 16 m core from a crater lake (Lake Tilla) in the Sudanian zone of NE-Nigeria provides a pollen record which can be dated back to approximately 11-12000 B.P. Preliminary pollen spectra show a relatively constant pattern with a dominance of grass pollen even during the middle Holocene.Deux sites situés dans la zone sahélienne et soudanienne du NE-Nigeria ont été choisi pour l'analyse de pollen. L'analyse palynologique d'une carotte provenant d'une dépression interdunaire dans les Manga Grassland de l'Est a mis en évidence de nouvelles informations sur l'histoire de la végétation holocène du Sahel entre ca. 9600 et 3400 B.P. Le profile pollinique de 3 m montre l'existence d'une savane ouverte pendant l'holocène moyen. La présence d'éléments soudano-guinéens dont l'extension était surtout limitée à la dépression interdunaire indique des conditions plus humides. Dès avant ca. 4000 B.P., un lent changement des conditions vers une plus grande sècheresse et l'établissement d'une végétation sahélienne comparable à l'actuelle est visible sur le diagramme. Cette évolution fut accompagnée de fortes fréquences de feu. Une carotte de 16 m d'un lac cratére (Lake Tilla) dans la zone soudanienne du NE-Nigeria proviens une profile de 11-12000 ans environs. Le spèctra polliniques préliminaires sont relativement constante avec une dominance de graminées même pendant l'Holocene moyen

Between desert and forest: the Holocene savannas of NE-Nigeria

Numerous ecologists postulate that West African savannas are mostly the result of degradation of formerly closed forests. This hypothesis can only be tested by palaeoecological investigations. The palynological results summarised in this paper document the history of the Sudanian and Sahelian savanna of NE-Nigeria during the last 11.500 years (uncal. BP). Both sites investigated provide evidence for the persistence of savanna throughout the entire Holocene. Patches of closed dry forest may have occurred, but never completely displaced the savanna vegetation. Humid conditions during the early and mid Holocene (from 10.000 BP onwards) caused a rapid spread of Guinean and Sudanian taxa into the northern vegetation zones. A slow return to drier climatic conditions between ca. 6800 BP and ca. 5500 BP can be recorded at both sites. Finally, between 3800 BP and 3300 BP a strong aridification resulted in the establishment of the modern vegetation zones. In both the Sahelian and Sudanian zone the vegetational changes appear to have been primarily controlled by climatic changes, whereas the effects of human activities remain palynologically silent even for the late Holocene

Reconstruction in German relative clauses : in favor of the matching analysis

In this paper I argue in favor of a Matching Analysis for German relative clauses. The Head Raising Analysis is shown to fail to account for parts of the reconstruction pattern in German, especially cases where only the external head is interpreted and the absence of Principle C effects. I propose a Matching Analysis with Vehicle Change and make consistent assumptions about possible deletion operations in relatives so that the entire pattern can be captured by one analysis which therefore proves superior to previous ones

On an alternative to long A´-movement in German and Dutch

This paper provides an analysis of an alternative strategy to A´-movement in both German and Dutch where the extracted constituent is preceded by a preposition and a coreferential pronoun appears in the extraction site. The construction has properties of both binding and movement: Whereas reconstruction effects suggest movement out of the embedded clause, there is strong evidence that the operator constituent is linked to an A-position in the matrix clause; this paradox is resolved by assuming a Control-like approach that involves movement from the embedded clause into a theta-position in the matrix clause with subsequent short A´- movement. The coreferential pronoun is interpreted as a resumptive heading a Big-DP which hosts the antecedent in its specifier