ALBERT

Notes: : This paper describes a procedure to design pluvial drainage systems in such a way as to prevent large excavation volumes and erosive velocities. To this end the storage capacity of the channel system is taken into account. In a preliminary step, the procedure employs an approximate method to determine the channel dimensions. Therefore, the dimensions are adjusted by means of a numerical method of solution of the unsteady flow equations. An example is included.

Notes: A study has been made of the effect of properties and composition of soils on the adsorption of ethofumesate. Adsorption isotherms of ethofumesate by agricultural and natural soils and by montmorillonite and humic acid were obtained. The correlations between the Freundlich K constants, and Kd distribution coefficients and the soil parameters were determined. Significant correlations (P〈0.05) were found between K and clay content and between Kd and smectite content for the agricultural soils but the correlation with organic matter content was of borderline or no significance.Considering the agricultural and natural soils together or the soils with an organic matter content 〉2%, a highly significant correlation was found between K and the organic matter content. According to the r2 determination coefficient, the organic matter content accounts for 88.4% of the variability in adsorption in the first case, and 92.2% in the second case. The log10 Kdom values of soils with an organic matter content 〉2% were similar and confirm the importance of the organic matter as a determinant parameter in the adsorption of ethofumesate by these soils. The adsorption of the herbicide by montmorillonite and humic acid confirmed the results obtained with the soils and point to the importance of the exchangeable cation nature of the samples and of the temperature in the adsorption process. Adsorption de l'éthofumesate dans des sols agri-coles et naturels L'effet des propriétés et de la composition du sol sur l'adsorption de l'ethofumesate a étéétudié. Les isothermes d'adsorption de 1'éthofumesate par des sols agricoles et naturels ainsi que par la montmorillonite et des acides humiques ont été déterminés. Les corrélations entre les caractéris-tiques du sol, les constantes de Freundlich K d'une part et les coefficients de distribution Kd d'autre part ont été déterminées. Des corrélations significatives (P〈0.05) ont été mises en évidence entre K et la teneur en argile ainsi qu'entre Kd et la teneur en smectite pour les sols agricoles mais la correlation avec la teneur en matisre organique etait tout juste ou non significative.Lorsqu'on considérait les sols agricoles et naturels ensemble ou les sols dont la teneur en matière organique est supérieure à 2%, une corrélation hautement significative existait entre K et la teneur en matière organique. Le coefficient de détermination r2 montre que la teneur en matière organique explique 88.4% de la vari-abilité de l'adsorption dans le premier cas et 92.2% dans le second cas. Le log10 Kdométait similaire pour les sols de teneur en matière organique 〉2%, ce qui confirme l'importance du paramètre matière organique dans l'adsorption de 1'ethofumesate par ces sols. L'adsorption de I'herbicide par la montmorillonite et les acides humiques a confirmé les résultats obtenus avec les sols et a montre 1'importance de la température du process et de la nature des cations d'échange des échantillons. Adsorption von Ethofumesat in Acker- and natürlichen Böden Bei der Untersuchung der Wirkung der Eigen-schaften und der Zusammensetzung von Böden auf die Adsorption von Ethofumesat wurden Adsorplions-Isothermen mit Acker- und natürlichen Böden sowie mit Montmorillonit und Huminsäure ermittelt. Die Korrelationen zwischen den Freundlich-Konstanten K sowie den Verteilungskoeffizienten Kd und den Bodenparametern wurden bestimmt. Signifikante Korrelationen (P〈0.05) wurden für K und den Tongehall und für Kd und den Smectit-Gehalt in Ackerböden gefunden, doch die Korrelation mit dem Gehalt an organischer Substanz war marginal oder nicht signifikant. Für Acker-und natürliche Böden insgesamt oder Böden mit einem Gehalt an organischer Substanz von 〉2% wurde eine hochsignifikante Korrelation zwischen K und dem Corg.-Gehalt gefunden. Das Bestimmtheitsmaß (r2) für die organische Substanz lag swischen 88.4% im ersten und 92.2% im zweiten Fall. Die log10Koc-Werte Böden mit einem Corg.-Gehalt von 〉2 % waren ähnlich und bestätigen die Bedeutung der organischen Substanz als bestimmenden Parameter für die Adsorption von Ethofumesat in diesen Böden. Die Adsorption des Herbizids an Montmorillonit und Huminsäure unterstreichen die an den Böden gewonnenen Ergebnisse und die Bedeutung der Kationen-Austauschfähigkeit der Proben.

Notes: Abstract. This paper presents evidence that firm-level productivity increases when the relative wage rises, or the level of unemployment rises. Both facts are consistent with the efficiency wage model. Moreover, there is support for the idea that an increase in the sector's wage with respect to the previous year also increases productivity. We obtain the empirical evidence through a double-hurdle model. We use this estimation technique because it can be established that the differences in productivity between sectors could be explained by differences in effort. It means that some of the industrial sectors of the Spanish economy may pay wage premia while others do not. We also test this implication through panel data.

Notes: The construct meaning of assessment center evaluations is an important unresolved issue in I/O psychology. This study hypothesized that Cognitive Ability and personality traits are primary correlates of evaluators’ overall assessment ratings (OARs). Meta–analysis results based on 65 correlations indicate the following mean construct–level correlations with OARs: .67 for Cognitive Ability, .50 for Extraversion, .35 for Emotional Stability, .25 for Openness, and .17 for Agreeableness; yielding a multiple R of .84. These findings support our hypothesis and cast light on the construct meaning of assessment center evaluations.

Notes: Abstract Sinefungin is a naturally occurring nucleoside isolated from cultures of Streptomyces griseolus and S. incarnatus. It is structurally related to S-adenosyl-methionine (SAM) and S-adenosyl-l-homocysteine (SAH). Its effect and level of action on prokaryotes has not been studied with the same detail as with eukaryotic cells. In this report we describe the effect of sinefungin and SAH on several Streptomyces methyltransferases (DNA) and protein MTases) and on other bacterial DNA-MTases. Protein Mtases are resistant to sinefungin, whereas DNA-MTases are inhibited. Adenine MTases however, seem more sensitive to this analogue than cytosine MTases.

Notes: Abstract Differences in plaque size of phages developing in Streptomyces antibiotics on several media were mainly determined by their adsorption ability to mycelium obtained at different stages of the bacterial growth-curve. This is due to the exposure of phages to the exocytoplasmic endodeoxyribonuclease produced by this bacterium at the middle-end of the exponential phase.

Notes: Abstract A protein that degrades pneumococcal walls containing choline, but not ethanolamine, in the teichoic acids has been isolated and purified from supernatants obtained from cultures of Clostridium acetobutylicum. The analyses of the degradation products of [3H]choline-labeled cell walls treated with this enzyme indicated that the purified protein, showing an apparent Mr of 115 000, is an N-acetylmuramyl-l-alanine amidase. Our results also suggest that C. acetobutylicum contains choline in its cell wall.

Notes: Abstract In this study the fatty acid composition of Flavobacterium halmephilum CCM2831 grown at different temperatures and salt concentrations is reported. At elevated growth temperatures the amount of cellular saturated long-chain acids (C18:0 and C20:0) and the branched-chain acid br-C17:0 increased, and the concentrations of both cyclic acids and the branched chain acid br-C15:0 decreased. Increasing the salt concentration in the medium resulted in a gradual increase in cellular cyclopropanoic acids and a concomitant decrease in the monounsaturated fatty acid content.

Notes: Abstract Erythromycin formation decreased in Streptomyces erythreus as a function of the ammonium concentration present in the medium. Total inhibition of synthesis was obtained with 100 mM NH4Cl but medium pH and culture growth were not significantly affected. A similar effect was obtained with NH4NO3 or (NH4)2SO4 indicating that ammonium ion probably repressed formation of antibiotic.