Super D-branes from BRST Symmetry

Recently a new formalism has been developed for the covariant quantization of superstrings. We study properties of Dp-branes and p-branes in this new framework, focusing on two different topics: effective actions and boundary states for Dp-branes. We present a derivation of the Wess-Zumino terms for super (D)p-branes using BRST symmetry. To achieve this we derive the BRST symmetry for superbranes, starting from the approach with/without pure spinors, and completely characterize the WZ terms as elements of the BRST cohomology. We also develope the boundary state description of Dp-branes by analyzing the boundary conditions for open strings in the completely covariant (i.e., without pure spinors) BRST formulation.Comment: 31 pp; journal version, expended discussion of D-brane pure spinor constraints in Section 2.

Twistor Strings with Flavour

We explore the tree-level description of a class of N=2 UV-finite SYM theories with fundamental flavour within a topological B-model twistor string framework. In particular, we identify the twistor dual of the Sp(N) gauge theory with one antisymmetric and four fundamental hypermultiplets, as well as that of the SU(N) theory with 2N hypermultiplets. This is achieved by suitably orientifolding/orbifolding the original N=4 setup of Witten and adding a certain number of new topological 'flavour'-branes at the orientifold/orbifold fixed planes to provide the fundamental matter. We further comment on the appearance of these objects in the B-model on CP(3|4). An interesting aspect of our construction is that, unlike the IIB description of these theories in terms of D3 and D7-branes, on the twistor side part of the global flavour symmetry is realised geometrically. We provide evidence for this correspondence by calculating and matching amplitudes on both sides.Comment: 38+12 pages; uses axodraw.sty. v2: References added, minor clarification

E-retailing ethics in Egypt and its effect on customer repurchase intention

The theoretical understanding of online shopping behaviour has received much attention. Less focus has been given to the formation of the ethical issues that result from online shopper interactions with e-retailers. The vast majority of earlier research on this area is conceptual in nature and limited in scope by focusing on consumers’ privacy issues. Therefore, the purpose of this paper is to propose a theoretical model explaining what factors contribute to online retailing ethics and its effect on customer repurchase intention. The data were analysed using variance-based structural equation modelling, employing partial least squares regression. Findings indicate that the five factors of the online retailing ethics (security, privacy, non- deception, fulfilment/reliability, and corporate social responsibility) are strongly predictive of online consumers’ repurchase intention. The results offer important implications for e-retailers and are likely to stimulate further research in the area of e-ethics from the consumers’ perspective

Why Customers Value Mass-customized Products: The Importance of Process Effort and Enjoyment

We test our hypotheses on 186 participants designing their own scarves with an MC toolkit. After completing the process, they submitted binding bids for "their" products in Vickrey auctions. We therefore observe real buying behavior, not merely stated intentions. We find that the subjective value of a self-designed product (i.e., one's bid in the course of the auction) is indeed not only impacted by the preference fit the customer expects it to deliver, but also by (1) the process enjoyment the customer reports, (2) the interaction of preference fit and process enjoyment, and (3) the interaction of preference fit and perceived process effort. In addition to its main effect, we interpret preference fit as a moderator of the valuegenerating effect of process evaluation: In cases where the outcome of the process is perceived as positive (high preference fit), the customer also interprets process effort as a positive accomplishment, and this positive affect adds (further) value to the product. It appears that the perception of the self-design process as a good or bad experience is partly constructed on the basis of the outcome of the process. In the opposite case (low preference fit), effort creates a negative affect which further reduces the subjective value of the product. Likewise, process enjoyment is amplified by preference fit, although enjoyment also has a significant main effect, which means that regardless of the outcome, customers attribute higher value to a self-designed product if they enjoy the process. The importance of the self-design process found in this study bears clear relevance for companies which offer or plan to offer MC systems. It is not sufficient to design MC toolkits in such a way that they allow customers to design products according to their preferences. The affect caused by this process is also highly important. Toolkits should therefore stimulate positive affective reactions and at the same time keep negative affect to a minimum. (authors' abstract

Consequences of Forcing Consumers to Use Technology-Based Self-Service

Today, traditional full service is increasingly replaced with technology-based self-service (TBSS), sometimes with no other option for service delivery. This study develops a conceptual model to investigate the impact of forcing consumers to use TBSS. The model is tested using an experimental design within railway (ticketing and travel information) contexts. The results show that forced use leads to negative attitudes toward using the TBSS as well as toward the service provider, and it indirectly leads to adverse effects on behavioral intentions. The findings also show that offering interaction with an employee as a fall-back option offsets the negative consequences of forced use, and that previous experience with TBSS (in general) leads to more positive attitudes toward the offered self-service, which can offset the negative effects of forced use to some extent

De invloed van gedwongen gebruik van technology-based self service

Vandaag de dag worden traditionele vormen van dienstverlening (bijvoorbeeld aan het loket) steeds vaker vervangen door een op een technologie gebaseerde vorm van zelfbediening, in dit artikel aangeduid als technology-based self-service (TBSS). Deze studie presenteert een model waarin wordt gekeken naar de invloed van gedwongen gebruik van TBSS. Het model is getest via een experimenteel onderzoek in de context van treinvervoer (het kopen van een vervoersbewijs en het verkrijgen van reisinformatie). De resultaten laten zien dat gedwongen gebruik tot een negatieve houding van de consument ten opzichte van zowel de TBSS als de dienstverlener leidt. Bovendien kan gedwongen gebruik indirect tot negatieve gedragsintenties leiden. De resultaten laten ook zien dat wanneer de klant een uitwijkmogelijkheid wordt geboden om contact met een medewerker te krijgen, de negatieve effecten van gedwongen gebruik voor een deel ongedaan gemaakt kunnen worden. Ten slotte vinden we in deze studie dat ervaring met andere vormen van zelfbediening tot meer positieve attitudes ten opzichte van de TBSS leidt, hetgeen de negatieve effecten van gedwongen gebruik ook enigszins kan reducere