Applicability of analysis techniques to determine consumer behaviour

To explain consumers’ actual buying behaviour, a choice experiment and a standardised interview shall be combined in a twofold methodological approach. While the choice experiment provides information about consumers’ buying behaviour, the interview shall examine backgrounds and reasons for the choice decision by investigating the internal factors consisting of consumer attitudes, motivations and emotions, as well as the external factors, which are socio-demographic characteristics. The data provided by this twofold methodological approach need to be linked in the analysis procedure. Thus, the aim of this paper is to discuss the applicability of single multivariate analysis techniques and their ability to explain consumer behaviour. To identify causalities between the observed behaviour and factors influencing the buying behaviour, two successive techniques are favoured. To reduce the large set of variables collected in the interview, a factor analysis is suggested. To link the variables of experiment and interview, both multiple regression analysis and ANOVA are applicable to explain causalities. Multiple regression analysis is suggested as it is more flexible towards the measurement level of the independent variable if only a small number of non-metric variables have to be transformed into dummy variables

Unfaithful Glitch Propagation in Existing Binary Circuit Models

We show that no existing continuous-time, binary value-domain model for digital circuits is able to correctly capture glitch propagation. Prominent examples of such models are based on pure delay channels (P), inertial delay channels (I), or the elaborate PID channels proposed by Bellido-D\'iaz et al. We accomplish our goal by considering the solvability/non-solvability border of a simple problem called Short-Pulse Filtration (SPF), which is closely related to arbitration and synchronization. On one hand, we prove that SPF is solvable in bounded time in any such model that provides channels with non-constant delay, like I and PID. This is in opposition to the impossibility of solving bounded SPF in real (physical) circuit models. On the other hand, for binary circuit models with constant-delay channels, we prove that SPF cannot be solved even in unbounded time; again in opposition to physical circuit models. Consequently, indeed none of the binary value-domain models proposed so far (and that we are aware of) faithfully captures glitch propagation of real circuits. We finally show that these modeling mismatches do not hold for the weaker eventual SPF problem.Comment: 23 pages, 15 figure

A geometric description of smooth cohomology

In this paper we give a geometric cobordism description of smooth integral cohomology. This model allows for simple descriptions of both the cup product and the integration, so that it is easy to verify the compatibilty of these structures.Comment: 15 page

Controlled nonuniformity in macroporous silicon pore growth

Photoelectrochemical etching of uniform prestructured silicon wafers in hydrofluoric acid containing solutions yields periodic structures that can be applied to two- and three-dimensional photonic crystals or microfluidics. Here we demonstrate experimentally macroporous silicon etching initiated by a nonuniform predefined lattice. For conveniently chosen parameters we observe a stable growth of pores whose geometrical appearance depends strongly on the spatially different nucleation conditions. Moreover, we show preliminary results on three-dimensionally shaped pores. This material can be used to realize hybrid photonic crystal structures and incorporate waveguides in three-dimensional photonic crystals

A multistate model for early decision making in oncology

The development of oncology drugs progresses through multiple phases, where after each phase a decision is made about whether to move a molecule forward. Early phase efficacy decisions are often made on the basis of single arm studies based on RECIST tumor response as endpoint. This decision rules are implicitly assuming some form of surrogacy between tumor response and long-term endpoints like progression-free survival (PFS) or overall survival (OS). The surrogacy is most often assessed as weak, but sufficient to allow a rapid decision making as early phase studies lack the survival follow up and number of patients to properly assess PFS or OS. With the emergence of therapies with new mechanisms of action, for which the link between RECIST tumor response and long-term endpoints is either not accessible yet because not enough data is available to perform a meta-regression, or the link is weaker than with classical chemotherapies, tumor response based rules may not be optimal. In this paper, we explore the use of a multistate model for decision making based on single-arm early phase trials. The multistate model allows to account for more information than the simple RECIST response status, namely, the time to get to response, the duration of response, the PFS time and time to death. We propose to base the decision on efficacy on the OS hazard ratio (HR), predicted from a multistate model based on early phase data with limited survival follow-up, combined with historical control data. Using three case studies and simulations, we illustrate the feasibility of the estimation of the OS HR using a multistate model based on limited data from early phase studies. We argue that, in the presence of limited follow up and small sample size, and on assumptions within the multistate model, the OS prediction is acceptable and may lead to better decisions for continuing the development of a drug

Influence of friction on granular segregation

Vertical shaking of a mixture of small and large beads can lead to segregation where the large beads either accumulate at the top of the sample, the so called Brazil Nut effect (BNE), or at the bottom, the Reverse Brazil Nut effect (RBNE). Here we demonstrate experimentally a sharp transition from the RBNE to the BNE when the particle coefficient of friction increases due to aging of the particles. This result can be explained by the two competing mechanisms of buoyancy and sidewall-driven convection, where the latter is assumed to grow in strength with increasing friction.Comment: 3 pages, 2 figure

In vivo application of recombinant interleukin 2 in the immunotherapy of established cytomegalovirus infection

We have shown in a murine model system for cytomegalovirus (CMV) disease in the immunocompromised host that in vivo application of recombinant human IL-2 (rhIL-2) can enhance the antiviral effect of a limited number of CD8+T lymphocytes, not only in prophylaxis, but also in therapy, when virus has already colonized host tissues. The observed net effect of IL-2 was consistent with the assumption of daily effector population doublings. The prospects for IL-2-supported immunotherapy of established CMV infection depend upon the tissues involved in disease. It appears that the prospects for controlling established CMV adrenalitis are less promising than for a therapy of interstitial CMV pneumonia

Optimized parallel tempering simulations of proteins

We apply a recently developed adaptive algorithm that systematically improves the efficiency of parallel tempering or replica exchange methods in the numerical simulation of small proteins. Feedback iterations allow us to identify an optimal set of temperatures/replicas which are found to concentrate at the bottlenecks of the simulations. A measure of convergence for the equilibration of the parallel tempering algorithm is discussed. We test our algorithm by simulating the 36-residue villin headpiece sub-domain HP-36 wherewe find a lowest-energy configuration with a root-mean-square-deviation of less than 4 Angstroem to the experimentally determined structure.Comment: 22 pages, 7 figure