J. Mol. Biol.

Cis-acting CCAAT elements are found frequently in eukaryotic promoter regions. Many of the genes containing such elements in their promoters are regulated by a conserved multimeric CCAAT- binding complex. In the fungus Emericella (Aspergillus) nidulans, this complex was designated AnCF (A. nidulans CCAAT- binding factor). AnCF regulates several genes, including the penicillin biosynthesis genes ipnA and aatA. Since it is estimated that the CCAAT-binding complex regulates more than 200 genes, an important question concerns the regulation mechanism that allows so many genes to be regulated by a single complex in a gene-specific manner. One of the answers to this question appears to lie in the interaction of AnCF with other transcription factors. Here, a novel transcription factor designated AnBH1 was isolated. The corresponding anbH1 gene was cloned and found to be located on chromosome IV. The deduced AnBH1 protein belongs to the family of basic-region helix-loop- helix (bHLH) transcription factors. AnBH1 binds in vitro as a homodimer to an, not previously described, asymmetric E-box within the aatA promoter that overlaps with the AnCF-binding site. This is the first report demonstrating that the CCAAT- binding complex and a bHLH transcription factor bind to overlapping sites. Since deletion of anbH1 appears to be lethal, the anbH1 gene was replaced by a regulatable alcAp- anbH1 gene fusion. The analysis of aatAp-lacZ expression in such a strain indicated that AnBH1 acts as a repressor of aatA gene expression and therefore counteracts the positive action of AnCF. (C) 2002 Elsevier Science Ltd. All rights reserved

Novel basic-region helix-loop-helix transcription factor (AnBH1) of Aspergillus nidulans counteracts the CCAAT-binding complex AnCF in the promoter of a penicillin biosynthesis gene

Cis-acting CCAAT elements are found frequently in eukaryotic promoter regions. Many of the genes containing such elements in their promoters are regulated by a conserved multimeric CCAAT- binding complex. In the fungus Emericella (Aspergillus) nidulans, this complex was designated AnCF (A. nidulans CCAAT- binding factor). AnCF regulates several genes, including the penicillin biosynthesis genes ipnA and aatA. Since it is estimated that the CCAAT-binding complex regulates more than 200 genes, an important question concerns the regulation mechanism that allows so many genes to be regulated by a single complex in a gene-specific manner. One of the answers to this question appears to lie in the interaction of AnCF with other transcription factors. Here, a novel transcription factor designated AnBH1 was isolated. The corresponding anbH1 gene was cloned and found to be located on chromosome IV. The deduced AnBH1 protein belongs to the family of basic-region helix-loop- helix (bHLH) transcription factors. AnBH1 binds in vitro as a homodimer to an, not previously described, asymmetric E-box within the aatA promoter that overlaps with the AnCF-binding site. This is the first report demonstrating that the CCAAT- binding complex and a bHLH transcription factor bind to overlapping sites. Since deletion of anbH1 appears to be lethal, the anbH1 gene was replaced by a regulatable alcAp- anbH1 gene fusion. The analysis of aatAp-lacZ expression in such a strain indicated that AnBH1 acts as a repressor of aatA gene expression and therefore counteracts the positive action of AnCF. (C) 2002 Elsevier Science Ltd. All rights reserved

DACH-Forschungsprojekt-Nutzungszeiten Offenporiger Asphaltdeckschichten

La réalisation de couches de surface en enrobé drainant est particulièrement motivée par le fort potentiel de réduction du bruit de ce type de surface en plus de sa capacité drainante. Des expériences en Autriche, en Allemagne et en Suisse ont aussi montré les effets négatifs de l'utilisation des couches de surface en enrobé drainant, comme par exemple des problèmes dans les procédures de maintenance hivernale (maintenance hivernale modifiée, consommation accrue de sel, déverglaçage, etc.) ou le comportement à long terme moins bon que celui d'un revêtement en enrobé conventionnel. Dans le contexte de ce travail de recherche (D-A-CH, projet en commun de l'Allemagne, l'Autriche et la Suisse) les couches de surface en enrobé drainant ont été examinées par rapport à leur durabilité structurelle et fonctionnelle, c'est-à- dire la durabilité de l'effet de réduction du bruit et de la capacité drainante. Avec l'aide d'un questionnaire, les expériences vécues en Autriche, en Allemagne et en Suisse ont été collectées, mises à jour et analysées. En général, les réponses au questionnaire montrent des expériences similaires avec ce type de couche de surface dans les trois pays. Les effets positifs qui ont été mentionnés par les personnes ayant répondu au questionnaire sont le potentiel de réduction du bruit et les progrès possibles dans la sécurité du trafic grâce à la capacité drainante accrue. Les effets les plus négatifs ont été mentionnés concernant les techniques modifiées de maintenance hivernale, le possible colmatage des vides et, en conséquence, un effet de réduction du bruit minimisé et une plus courte durée de vie structurelle par rapport aux couches de surface en enrobé dense. En guise de résultat de l'analyse du questionnaire, le consortium de projet conseille d'approfondir les recherches en résolvant les problèmes principaux concernant les surfaces en enrobé drainant: sécurité routière, durée de vie structurelle et durée de vie acoustique. En particulier, il serait nécessaire et utile de faire davantage de mesures et d'observations concernant les conditions de surface et les émissions de bruit pendant un certain laps de temps pour améliorer nos connaissances sur les performances à long terme des couches de surface en enrobé drainant

Recommendations on Specifications for Tyre and Vehicle Requirements

This report gives an overview of the general effects of various tyre and vehicle parameters, a brief review of the SILVIA database, and analyses of the influences of various tyre and vehicle parameters on traffic noise. These analyses are based on data present in the SILVIA database, supplemented with results from relevant literature. Based on these analyses recommendations have been made concerning guidelines for vehicle and tyre manufacturers and legislators as a way to improve the performance of low noise surfaces through optimising the vehicle and tyres

Coordination of user and agency costs using two-level approach for pavement management optimization

Pavement maintenance and rehabilitation programming requires the consideration of conflicting objectives in order to optimize its life-cycle costs. While there are several approaches to solve multi-objective problems for pavement management systems, when user costs or environmental impacts are considered, the optimal solutions are often unpractical to be accepted by road agencies, given the dominating share of user costs in the total life-cycle costs. This paper presents a two-stage optimization methodology that considers maximization of pavement quality and minimization of agency costs as the objectives to be optimized at the pavement section level, while at the network level, the objectives are to minimize agency and user costs. The main goal of this approach is to provide decision-makers with a range of optimal solutions from which a practically implementable one could be selected by the agency concerned. A sensitivity analysis and some trade-off graphics illustrate the importance in balancing all the objectives in order to obtain reasonable solutions for highway agencies. The multi-objective optimization problems at both levels are solved using genetic algorithms. The results of a case study indicate the applicability of the methodology.The authors thank Fundação para a Ciência e a Tecnologia for the PhD scholarship.info:eu-repo/semantics/submittedVersio