Retail positioning through customer satisfaction: an alternative explanation to the resource-based view

Through exploring factors influencing effective retail positioning strategies in an emerging market environment, this paper challenges the role of isolation mechanism and heterogeneous idiosyncrasy argued by the resource-based view theory. By drawing on a sample of 11,577 customers from hypermarkets, electronic appliance specialty stores and department stores in major Chinese cities, we set up ten hypotheses and confirm a nine-item model for customeroriented retail positioning (perceived price, store image, product, shopping environment, customer service, payment process, after-sales service, store policies, and shopping convenience). Our results show that different retail formats achieve success through the implementation of similar positioning strategies, in which case, it is not heterogeneity but homogeneity that contributes to retailers' success greatly at the development stage of retail expansion. Our results challenge previously proved effectiveness of inimitability to success by the resource-based view, and support homogenous idiosyncrasy of retailers in the implementation of customer-oriented positioning strategies in an emerging market

Exciton spin dynamics and photoluminescence polarization of CdSe/CdS dot-in-rod nanocrystals in high magnetic fields

The exciton spin dynamics and polarization properties of the related emission are investigated in colloidal CdSe/CdS dot-in-rod (DiR) and spherical core/shell nanocrystal (NC) ensembles by magneto-optical photoluminescence (PL) spectroscopy in magnetic fields up to 15 T. It is shown that the degree of circular polarization (DCP) of the exciton emission induced by the magnetic field is affected by the NC geometry as well as the exciton fine structure and can provide information on nanorod orientation. A theory to describe the circular and linear polarization properties of the NC emission in magnetic field is developed. It takes into account phonon mediated coupling between the exciton fine structure states as well as the dielectric enhancement effect resulting from the anisotropic shell of DiR NCs. This theoretical approach is used to model the experimental results and allows us to explain most of the measured features. The spin dynamics of the dark excitons is investigated in magnetic fields by time-resolved photoluminescence. The results highlight the importance of confined acoustic phonons in the spin relaxation of dark excitons. The bare core surface as well as the core/shell interface give rise to an efficient spin relaxation channel, while the surface of core/shell NCs seems to play only a minor role.Comment: 18 pages, 15 figure

Social Media and Distraction: An Experience Sampling Study among Adolescents

A widespread concern in society is that adolescents experience an increased inability to concentrate and sustain attention because they are continuously distracted by social media. The current experience sampling method (ESM) study examined whether adolescents who use more social media than their peers experience more distraction (between-person association), whether social media use (SMU) and distraction co-fluctuate within adolescents (momentary within-person associations), and to what extent this within-person association differs from person to person (person-specific associations). With a sample of 383 adolescents (Mage = 14.11), who together completed 35,099 ESM surveys (73% compliance), we found both a positive between-person association (β = .31) and a positive momentary within-person association (β = .12) of SMU with distraction. The momentary within-person association differed from adolescent to adolescent: While SMU and distraction were positively associated among 82.5% of all adolescents, they were not associated among 15.7% of the adolescents, and negatively associated among 1.8% of the adolescents. Additional analyses on the direction of the effect showed that the within-person effect of SMU on subsequent levels of distraction was somewhat stronger (β = .05) than the effect of distraction on subsequent levels of SMU (β = .03)

Simulation model of wax diffusion and cleaning in printer belts

A belt that transports toner is one of the vital components of a printer. Since toner is fused to the paper at a high temperature, wax releases from the paper and penetrates into the rubber top layer of the belt. When the rubber becomes saturated with wax, the wax remains on top of the belt. The formed layer of wax has negative impact on the image forming unit leading to bad printing quality. Thus, a wax cleaner is installed. To determine optimal functioning of the cleaner, time consuming and inefficient experiments have to be carried out. Thus, an efficient simulation tool to predict wax build-up and cleaning may replace the experiments. Simulation is based on a mathematical model that describes the influx of wax as a convection/diffusion process. The standard numerical discretization methods to calculate the evolution in time of the wax concentration are not applicable. Saturation is reached after ten thousands of rounds. In this article, we propose a combination of an analytical and a numerical method to tackle the problem, where we discretize the second-order differential operator that generates the evolution of the wax concentration. The simulations show an adequate fit with results from measurement. The wax build-up in the belt up to saturation is described realistically. Our study reveals that the contact resistance between belt and cleaner is the most important parameter that influences the effectiveness of the cleaner. Keywords: (Wax) Diffusion – Eigenvalue – Multi-layered medium – Printing belt – Printing syste

Juxtaposition of system dynamics and agent-based simulation for a case study in immunosenescence

Advances in healthcare and in the quality of life significantly increase human life expectancy. With the aging of populations, new un-faced challenges are brought to science. The human body is naturally selected to be well-functioning until the age of reproduction to keep the species alive. However, as the lifespan extends, unseen problems due to the body deterioration emerge. There are several age-related diseases with no appropriate treatment; therefore, the complex aging phenomena needs further understanding. It is known that immunosenescence is highly correlated to the negative effects of aging. In this work we advocate the use of simulation as a tool to assist the understanding of immune aging phenomena. In particular, we are comparing system dynamics modelling and simulation (SDMS) and agent-based modelling and simulation (ABMS) for the case of age-related depletion of naive T cells in the organism. We address the following research questions: Which simulation approach is more suitable for this problem? Can these approaches be employed interchangeably? Is there any benefit of using one approach compared to the other? Results show that both simulation outcomes closely fit the observed data and existing mathematical model; and the likely contribution of each of the naive T cell repertoire maintenance method can therefore be estimated. The differences observed in the outcomes of both approaches are due to the probabilistic character of ABMS contrasted to SDMS. However, they do not interfere in the overall expected dynamics of the populations. In this case, therefore, they can be employed interchangeably, with SDMS being simpler to implement and taking less computational resources

Using agent-based modelling for investigating modal shift: The case of university travel

© 2019 Travel mode choices are a result of several factors and how they affect individual travellers. This paper examines those factors influencing travellers’ mode choices commuting to and from a university. Furthermore, we investigate how a shift to alternative modes can be stimulated within the current transport system environment of that university. From focus groups studies, seven measurable themes were identified as metrics for travellers’ satisfaction. Descriptive data has been collected from 348 participants through questionnaires. The analysis of the questionnaires provided insights into the development of appropriate policies to stimulate travellers’ mode shift. To allow for studying the impact of applying proposed interventions over time, we simulated the effects of those interventions on travellers’ mode choice by using an agent-based social simulation approach. We employed a framework designed for modelling modal shift in the transport domain to build the simulation model, taking the themes into consideration. The outcomes of the study assisted in understanding how decision factors and their interconnections contribute to sub-populations of travellers’ choice. In addition, our experiments helped in assessing the importance of interactions among travellers on their decision making. Such an understanding provides insight into those factors within the system that need to be considered when policymakers develop strategies for interventions for mode shift. The outcomes of the simulation experiments indicate that different policy interventions result in distinct travellers’ mode adoption patterns and that interventions perform better when the right categories or groups of travellers are targeted. In addition, the intervention should focus on the right travellers’ concerns and be applied in the right proportion. This social simulation study has also demonstrated how a theory-based framework can be used with survey data in numerical experiments to explore real-life scenarios for the development of actions to promote behavioural changes

Discovering novel hydrolases from hot environments

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordNovel hydrolases from hot and other extreme environments showing appropriate performance and/or novel functionalities and new approaches for their systematic screening are of great interest for developing new processes, for improving safety, health and environment issues. Existing processes could benefit as well from their properties. The workflow, based on the HotZyme project, describes a multitude of technologies and their integration from discovery to application, providing new tools for discovering, identifying and characterizing more novel thermostable hydrolases with desired functions from hot terrestrial and marine environments. To this end, hot springs worldwide were mined, resulting in hundreds of environmental samples and thousands of enrichment cultures growing on polymeric substrates of industrial interest. Using high-throughput sequencing and bioinformatics, 15 hot spring metagenomes, as well as several sequenced isolate genomes and transcriptomes were obtained. To facilitate the discovery of novel hydrolases, the annotation platform Anastasia and a whole-cell bioreporter-based functional screening method were developed. Sequence-based screening and functional screening together resulted in about 100 potentially new hydrolases of which more than a dozen have been characterized comprehensively from a biochemical and structural perspective. The characterized hydrolases include thermostable carboxylesterases, enol lactonases, quorum sensing lactonases, gluconolactonases, epoxide hydrolases, and cellulases. Apart from these novel thermostable hydrolases, the project generated an enormous amount of samples and data, thereby allowing the future discovery of even more novel enzymes.European CommissionEuropean Union FP

N-Myc-induced metabolic rewiring creates novel therapeutic vulnerabilities in neuroblastoma

N-Myc is a transcription factor that is aberrantly expressed in many tumor types and is often correlated with poor patient prognosis. Recently, several lines of evidence pointed to the fact that oncogenic activation of Myc family proteins is concomitant with reprogramming of tumor cells to cope with an enhanced need for metabolites during cell growth. These adaptions are driven by the ability of Myc proteins to act as transcriptional amplifiers in a tissue-of-origin specific manner. Here, we describe the effects of N-Myc overexpression on metabolic reprogramming in neuroblastoma cells. Ectopic expression of N-Myc induced a glycolytic switch that was concomitant with enhanced sensitivity towards 2-deoxyglucose, an inhibitor of glycolysis. Moreover, global metabolic profiling revealed extensive alterations in the cellular metabolome resulting from overexpression of N-Myc. Limited supply with either of the two main carbon sources, glucose or glutamine, resulted in distinct shifts in steady-state metabolite levels and significant changes in glutathione metabolism. Interestingly, interference with glutamine-glutamate conversion preferentially blocked proliferation of N-Myc overexpressing cells, when glutamine levels were reduced. Thus, our study uncovered N-Myc induction and nutrient levels as important metabolic master switches in neuroblastoma cells and identified critical nodes that restrict tumor cell proliferation

A systems biology approach reveals major metabolic changes in the thermoacidophilic archaeon Sulfolobus solfataricus in response to the carbon source L-fucose versus D-glucose

Archaea are characterised by a complex metabolism with many unique enzymes that differ from their bacterial and eukaryotic counterparts. The thermoacidophilic archaeon Sulfolobus solfataricus is known for its metabolic versatility and is able to utilize a great variety of different carbon sources. However, the underlying degradation pathways and their regulation are often unknown. In this work, we analyse growth on different carbon sources using an integrated systems biology approach. The comparison of growth on L-fucose and D-glucose allows first insights into the genome-wide changes in response to the two carbon sources and revealed a new pathway for L-fucose degradation in S. solfataricus. During growth on L-fucose we observed major changes in the central carbon metabolic network, as well as an increased activity of the glyoxylate bypass and the 3-hydroxypropionate/4-hydroxybutyrate cycle. Within the newly discovered pathway for L-fucose degradation the following key reactions were identified: (i) L-fucose oxidation to L-fuconate via a dehydrogenase, (ii) dehydration to 2-keto-3-deoxy-L-fuconate via dehydratase, (iii) 2-keto-3-deoxy-L-fuconate cleavage to pyruvate and L-lactaldehyde via aldolase and (iv) L-lactaldehyde conversion to L-lactate via aldehyde dehydrogenase. This pathway as well as L-fucose transport shows interesting overlaps to the D-arabinose pathway, representing another example for pathway promiscuity in Sulfolobus species