CadC-mediated activation of the cadBA promoter in Escherichia coli

The transcriptional activator CadC in Escherichia coli, a member of the ToxR-like proteins, activates transcription of the cadBA operon encoding the lysine decarboxylase CadA and the lysine-cadaverine antiporter CadB. cadBA is induced under conditions of acidic external pH and exogenous lysine; anoxic conditions raise the expression level up to 10 times. To characterize the binding mechanism of CadC, procedures for the purification of this membrane-integrated protein and its reconstitution into proteoliposomes were established. The binding sites of CadC upstream of the cadBA promoter region were determined by in vitro DNaseI protection analysis. Two regions were protected during DNaseI digestion, one from - 144 to - 112 bp, designated Cad1, and another one from - 89 to - 59 bp, designated Cad2. Binding of purified CadC to Cad1 and Cad2 was further characterized by DNA-binding assays, indicating that CadC was able to bind to both DNA fragments. Genetic analysis with promoter-lacZ fusions confirmed that both sites, Cad1 and Cad2, are essential for activation of cadBA transcription. Moreover, these experiments revealed that binding of H-NS upstream of the CadC-binding sites is necessary for repression of cadBA expression at neutral pH and under aerobic conditions. Based on these results, a model for transcriptional regulation of the cadBA operon is proposed, according to which H-NS is involved in the formation of a repression complex under non-inducing conditions. This complex is dissolved by binding of CadC to Cad1 under inducing conditions. Upon binding of CadC to Cad2 cadBA expression is activated. Copyright (C) 2005 S. Karger AG, Basel

Silicon surface passivation for devices Quarterly status report

Water contamination in thermal oxide on silico

Dynamic conditional correlation analysis of financial market interdependence: An application to Thailand and Indonesia

This paper examines the dynamic linkages among financial markets in Thailand and Indonesia. In particular, we focus on the cross-border relationship in individual markets and on the relationship between finan- cial markets within each country. We find that while tight monetary policy pursued by Thailand authorities helped to defend the exchange rate at the outbreak of the financial crisis, it had little consequences for Indonesia at the end of 1998. The correlations between countries within each of the financial market reveals a certain degree of interde- pendence among countries, which is lower during crises.

Study of dynamics of charge trapping in a-Si:H/SiN TFTs

In this paper we present the study of the failure mechanism responsible for long-term degradation that ultimately leads to instability in a-Si:H/SiN TFTs. The experimental data points we obtain by monitoring in-situ the drain current during gate bias stress (forward and reverse bias) and relaxation could not be fitted with the models existent in the literature. A new model that we have christened "Progressive Degradation Model" (PDM) emerged. The model makes use of Heimann-Warfield theory of trapping/detrapping front. PDM achieves a consistent fit to any bias condition showing that the degradation can be modelled quantitatively yielding the number of traps involved, their position and the charge dispersion coefficient. According to PDM the degradation of electrical response is a combined effect of a fast interface traps generation and a slow charge trapping at the created defect sites in a-SiN:H transitional region

Flexible Sensor Network Reprogramming for Logistics

Besides the currently realized applications, Wireless Sensor Networks can be put to use in logistics processes. However, doing so requires a level of flexibility and safety not provided by the current WSN software platforms. This paper discusses a logistics scenario, and presents SensorScheme, a runtime environment used to realize this scenario, based on semantics of the Scheme programming language. SensorScheme is a general purpose WSN platform, providing dynamic reprogramming, memory safety (sandboxing), blocking I/O, marshalled communication, compact code transport. It improves on the state of the art by making better use of the little available memory, thereby providing greater capability in terms of program size and complexity. We illustrate the use of our platform with some application examples, and provide experimental results to show its compactness, speed of operation and energy efficiency

Olympic participation and performance since 1896

Abstract We analyze the decision to participate and Olympic performance at the country level. We use an unbalanced panel of 118 countries over 24 editions of the Olympic Summer Games. The main focus of the paper is on economic, geographic and demographic explanations of Olympic participation and success. We estimate the impact of income per capita, population size, home advantage, and institutional variables on participation and success rates. We present separate results for events before the Second World War and after. These results show that income is an important determinant of Olympic participation and success. Socialist countries send more athletes to the games and have more success in medal counts. The home advantage has become less prominent.

Binary Relations as a Foundation of Mathematics

We describe a theory for binary relations in the Zermelo-Fraenkel style. We choose for ZFCU, a variant of ZFC Set theory in which the Axiom of Foundation is replaced by an axiom allowing for non-wellfounded sets. The theory of binary relations is shown to be equi-consistent ZFCU by constructing a model for the theory of binary relations in ZFU and vice versa. Thus, binary relations are a foundation for mathematics in the same sense as sets are

Agriculture in motion: Intertwined geographical and socio-professional mobilities in North Africa's groundwater economy

In this paper, we examine the greenhouse horticulture in Algeria's Sahara, which is one illustrative example of the agricultural transitions that have taken place in North Africa on the new irrigation frontiers created through groundwater use. The entrepreneurial farming systems in the region are characterized by considerable mobility. Geographic mobilities of people, ideas, capital, information, and objects and socio-professional mobilities are intrinsically intertwined, whereby skilled sha-recroppers and laborers move sometimes over hundreds of kilometers, attracted by the opportunities of quick monetary gains and by the opportunities of rapid so-cio-professional upward mobility. This paper analyzes, first the different forms of socio-professional and geographical mobilities associated with the groundwater-ba-sed farming systems in Algeria's Sahara, with a particular focus on mobile young farmers; then focuses on the multiple borders that these young farmers crossed on their trajectory; and their return journey after they quit the Sahara