Conserved Aspartate Residues and Phosphorylation in Signal Transduction by the Chemotaxis Protein CheY

The CheY protein is phosphorylated by CheA and dephosphorylated by CheZ as part of the chemotactic signal transduction pathway in Escherichia coli. Phosphorylation of CheY has been proposed to occur on an aspartate residue. Each of the eight aspartate residues of CheY was replaced by using site-directed mutagenesis. Substitutions at Asp-12, Asp-13, or Asp-57 resulted in loss of chemotaxis. Most of the mutant CheY proteins were still phosphorylated by CheA but exhibited modified biochemical properties, including reduced ability to accept phosphate from CheA, altered phosphate group stability, and/or resistance to CheZ-mediated dephosphorylation. The properties of CheY proteins bearing a substitution at position 57 were most aberrant, consistent with the hypothesis that Asp-57 is the normal site of acyl phosphate formation. Evidence for an alternate site of phosphorylation in the Asp-57 mutants is presented. Phosphorylated CheY is believed to cause tumbling behavior. However, a dominant mutant CheY protein that was not phosphorylated in vitro caused tumbling in vivo in the absence of CheA. This phenotype suggests that the role of phosphorylation in the wild-type CheY protein is to stabilize a transient conformational change that can generate tumbling behavior

Vorteile des Traubenteilens

Die Ertragsregulierung durch Halbieren von Trauben wird bereits von etlichen Deutschschweizer Winzern praktiziert. Es liegen auch Untersuchungen aus dem Ausland vor. Man erhofft sich von dieser Methode unter anderem Vorteile bezüglich Botrytisbefall und Weinqualität. Im Rahmen einer Diplomarbeit an der Hochschule Wädenswil im Jahr 2006 wurde an drei Standorten (Fläsch, Stäfa, Halbinsel Au) bei der Sorte Blauburgunder der Einfluss des Traubenteilens auf die Ertragsbildung, den Most und den Wein untersucht

Logic Multiplicity in Digital Business Models – An Institutional Logics Perspective

Digital business models (DBM) are built upon digital technologies with complexity-inducing characteristics, connecting multiple heterogeneous actors seeking to co-create value. Institutional logics coordinate and constrain actors’ value co-creation interactions. Multiple, competing institutional logics can co-exist and create barriers to value co-creation. However, we argue that business model research in the information systems (IS) discipline still assumes a homogeneous concept, overlooking the possibility of logic multiplicity within DBMs. We conceptually show why logic multiplicity should be acknowledged and derive three propositions introducing logic multiplicity to the structures and practices of DBMs. By assuming an institutional logics perspective, challenging the assumption of homogeneity, and introducing a logic multiplicity lens, we call for a return to the discipline’s sociotechnical roots. We thereby enable scholars to study the complex reality of digital business and aid practitioners in turning situations of multiplicity into opportunities

Changing Concepts of Work in Thailand

Historically in Thai society 'work' has been defined broadly but recent economic changes have led to a narrowing of ideas about what constitutes work. The commodification of labour this entails is familiar from the history of economic change in many nations. This article seeks to go beyond re-stating the obvious parallels. In particular, because the specificities of these changes in each nation reveal underpinning attitudes to work, we believe that they have significance for understanding worker attitudes and therefore for decision making on both labour policy and management practice. Some Thais defining work will recite a 1950's slogan introduced by the military dictator Sarit that states 'ngan khu ngern, ngern khu ngan, banda suk', which means work is money, money is work and this brings us happiness. This article seeks an understanding of what this means in practice. It begins by looking generally at broad concepts of work and economic development. It then considers how this has impacted on language and normative values in other nations, and looks at how economic change in Thailand has led to a profound shift in attitudes to work. In particular attention is focused on the language used to describe work because this language is redolent of the process of cultural legitimisation by which working for money becomes normative. The article uses both Thai and Isarn (the name given to the dialect and region in Northeast Thailand) illustrations to show usage change in both urban and rural areas

CONSUMER USE OF SOCIAL LIVE STREAMING SERVICES: THE INFLUENCE OF CO-EXPERIENCE AND EFFECTANCE ON ENJOYMENT

Social live streaming services (SLSS) have emerged as a new type of hedonic social media. SLSS allow users to watch and broadcast video streams in real-time, fostering sociability through synchronous communication via chat channels. While the extant literature has mostly examined producers’ use of SLSS, the consumer perspective has been underexplored. Prior research has identified perceived enjoyment as consumers’ primary motivation to use hedonic social media. However, it remains unclear how the specific affordances of SLSS affect consumers’ enjoyment. Due to their synchronous nature, SLSS enable consumers to co-experience live streams together and to perceive so-called “effectance” by shaping the content of live streams through their actions. Consequently, research is required on how both co-experience and effectance influence consumers’ enjoyment of SLSS. We empirically address this research gap by applying partial least squares equation modeling on web survey data of 127 consumers of SLSS. Our results show that consumers’ perceived co-experience has a strong positive effect on the enjoyment of their active behavior (chatting) and their passive behavior (watching). Perceived effectance, however, only shows a positive impact on the enjoyment of active behavior, while playing no role for the enjoyment of passive behavior

Study of helicopterroll control effectiveness criteria

A study of helicopter roll control effectiveness based on closed-loop task performance measurement and modeling is presented. Roll control critieria are based on task margin, the excess of vehicle task performance capability over the pilot's task performance demand. Appropriate helicopter roll axis dynamic models are defined for use with analytic models for task performance. Both near-earth and up-and-away large-amplitude maneuvering phases are considered. The results of in-flight and moving-base simulation measurements are presented to support the roll control effectiveness criteria offered. This Volume contains the theoretical analysis, simulation results and criteria development

Doing Well by Doing Fair? Investigating the Effect of Users’ Fairness Perceptions on Adoption Intentions of Services

Within the IS discipline, the concept of fairness as a determinant for social good recently gained attention. However, a comprehensive understanding of the influence of different fairness dimensions on user perceptions and their adoption intention of new technologies is missing. Based on fairness research, the FAIRSERV model, and the technology acceptance model, we derived a research model to study how users’ fairness perceptions along different dimensions influence their adoption intentions in the context of online services. We tested our model in an online experiment with 407 participants. Our results show that perceived distributive, procedural, and interactional fairness positively influence users’ perceived overall fairness regarding an online service, which, in return, positively influences their adoption intentions. We contribute to IS research by shedding light on the societal impact of fairness in the context of adopting new digital services. Practitioners can utilize our findings to improve their service offerings

The new economic geography of SADC free trade area

The current implementation of a free trade area in SADC has given rise to concerns that the present location of industry in the region will be adversely affected. Specifically, many of the smaller and less-developed countries fear that this change will result in a loss of their industry towards the more developed members, and particularly towards South Africa. This study uses the framework of the new economic geography to address these concerns. The new economic geography is a body of theory that has arisen in the last decade and allows for a dynamic analysis of the process of regional integration. Studies of such dynamic effects in the developing country context are exceedingly scarce, and particularly so in southern Africa. Another area of little research is in the comparison of the evolving industrial structure of different regional blocs. Thus, in response to this gap in the literature and in order to address the concerns of polarisation of industry within the SADC region, a two-pronged empirical approach is taken. The study first conducts a review of the spatial distribution of industry within SADC from 1970 to 1999. This is achieved through the calculation and examination of industrial locational Gini coefficients, measuring the relative degree of concentration of 28 ISIC (rev 2) industries for the years 1970, 1980, 1985, 1990, 1995 and 1999. Secondly, an empirical comparison is conducted with other blocs that are in the process of deepening regional integration, namely the European Union and Mercosur. Again, this is done through the calculation of locational Gini coefficients for individual industries for all three blocs at five year intervals from 1980 to 1995, and then for 1999. The average level of concentration within SADC is found to increase steadily from 1970 to 1990. Between 1990 and 1995, the level of concentration increases further, but at a lower rate, and, by 1999 industry begins to disperse. The Gini coefficient is a relative measure, and thus does not measure the absolute level of concentration. Thus, much of the increase in concentration seen is towards peripheral countries. To further interpret the Gini, the changes in concentration are compared to the absolute changes in manufacturing employment in South Africa. From this analysis, eight of the 28 industries analysed show particular tendencies to concentrate in the periphery. These are beverages, textiles, wearing apparel, paper and products, rubber products, other non-metallic mineral products, transport equipment, and professional and scientific equipment. Likewise, another six industries become more concentrated in South Africa over this time, namely food products, printing and publishing, industrial chemicals, petroleum refineries, miscellaneous petroleum and coal products, and electrical machinery. According to the Gini coefficient, the tobacco industry is by far the most concentrated, while the wood products industry is the most dispersed. It is also found that scale-intensive industries tend to be among the most concentrated. In the cross-bloc comparison, Mercosur has the lowest level of aggregate concentration with an average Gini of 0.08 in 1999. This compares with Ginis of 0.28 for the EU, and 0.22 for SADC. The EU has the largest increase in concentration over the period, while the concentration in Mercosur falls during the 1980s, increases in the mid 1990s and then falls again by 1999. A common theme, however, between all three blocs is a trend towards dispersion in the late 1990s. This is particularly apparent in SADC and Mercosur where the Gini decreases in value, while in the EU, the Gini only increases marginally in this period. Other studies of the EU have indicated that industry was starting to disperse at this time. This finding would be more apparent at a greater level of industrial disaggregation. The following industries are found to be agglomerated above the average level in all three blocs: tobacco, miscellaneous petroleum and coal products, and pottery china and earthenware. Conversely, transport equipment, paper and products, machinery except electrical, plastic products, rubber products, and fabricated metal products tend to be more dispersed across all three. Perhaps more interesting is that there appears to be some commonality between industries that become more agglomerated across all three blocs, while industries that dispersed tend to be region specific. The industries that show universal agglomeration tendencies are the highly sensitive wearing apparel and textiles industries, in addition to industrial chemicals, printing and publishing, iron and steel, and plastic products. In relation to SADC, the first two of these industries show an increased concentration in the periphery, as in the EU, while the remaining industries show tendencies to concentrate in the core. The new economic geography predicts that, as the presently high levels of transport costs begin to fall in SADC, industry will tend to concentrate in the core. However, the results of this study indicate that the effect on manufacturing is, to a large extent, sector specific, with some manufacturing industries concentrating in the core and others in the periphery. The study therefore concludes that the mass polarization of industry from the smaller countries in SADC towards South Africa is unlikely to occur with the further reduction in trade costs. Although certain industries may be attracted towards the core, the high degree of wage disparity in the region and present trade concessions from developed markets overseas towards the peripheral countries, will make these countries an attractive location, particularly for export orientated firms. Two main policy recommendations result from the study. Firstly, individual countries in SADC need to promote those industries that show concentration tendencies in their country. Secondly, in order for the periphery to maximize their gain from the free trade area, transport costs within the region need to be reduced rapidly and effectively