Search results for "replica"
showing 10 items of 576 documents
Evolutionary psychological consumer research:Bold, bright, but better with behavior
2020
Abstract This special issue includes state-of-the-art papers that leverage various theories from evolutionary psychology (EP) to shed light on important consumption-related phenomena. Our guest editorial provides an overview of this EP-based consumer research, highlighting the key content, common denominators, and significant strengths of the articles. The papers cover a wide variety of topics, characteristic of evolutionary-informed research, that we structure around the following three themes: (1) Mating, marketing, and meaningful motivating forces, (2) Conspicuous consumption and salient signs of “showing off,” and (3) Human hormones and biologically-based business research. We close our…
Creating Defined 3-D Defects Inside an Opaline Ormocer® Matrix with Two-Photon Lithography
2007
The creation of defined structures inside a synthetic opal is a key step toward applications in optics, where control of the propagation of light inside a photonic crystal is necessary. In a previous paper, we described the nanostructuring of Ormocer® to form inverse opals (Lange et al., Macromol. Rapid Commun. 2006, 27, 1746). Here, we report an application for this robust replica process in which defects can be directly produced within the PC by two-photon lithography. The holes of an inverse opal structure are first filled with a resin of similar refractive index. In this transparent material, polymerization can be initiated at defined places via two-photon lithography. After removal of …
Electrodeposition of ZnO nanorods on opaline replica as hierarchically structured systems
2011
We present a new method to prepare hierarchical structures by using ZnO replica and ZnO-coated PMMA opals as electrodes in an electrodeposition process of ZnO nanorods. Depending on the approach the nanorods can be either grown exclusively on top of the replica or inside the replica structures. Therefore two types of systems are accessible: 3D photonic crystals with a hierarchically structured surface consisting of nanorods and macroporous ZnO structures with an increased surface area.
Portfolios with fuzzy returns: Selection strategies based on semi-infinite programming
2008
AbstractThis paper provides new models for portfolio selection in which the returns on securities are considered fuzzy numbers rather than random variables. The investor's problem is to find the portfolio that minimizes the risk of achieving a return that is not less than the return of a riskless asset. The corresponding optimal portfolio is derived using semi-infinite programming in a soft framework. The return on each asset and their membership functions are described using historical data. The investment risk is approximated by mean intervals which evaluate the downside risk for a given fuzzy portfolio. This approach is illustrated with a numerical example.
Continuous-time portfolio optimization under terminal wealth constraints
1995
Typically portfolio analysis is based on the expected utility or the mean-variance approach. Although the expected utility approach is the more general one, practitioners still appreciate the mean-variance approach. We give a common framework including both types of selection criteria as special cases by considering portfolio problems with terminal wealth constraints. Moreover, we propose a solution method for such constrained problems.
A Conditional Value–at–Risk Model for Insurance Products with Guarantee
2009
We propose a model to select the optimal portfolio which underlies insurance policies with a guarantee. The objective function is defined in order to minimise the conditional value at-risk (CVaR) of the distribution of the losses with respect to a target return. We add operational and regulatory constraints to make the model as flexible as possible when used for real applications. We show that the integration of the asset and liability side yields superior performances with respect to naive fixed-mix portfolios and asset based strategies. We validate the model on out-of-sample scenarios and provide insights on policy design.
We need more replication research – A case for test-retest reliability
2017
Following debates in psychology on the importance of replication research, we have also started to see pleas for a more prominent role for replication research in medical education. To enable replication research, it is of paramount importance to carefully study the reliability of the instruments we use. Cronbach’s alpha has been the most widely used estimator of reliability in the field of medical education, notably as some kind of quality label of test or questionnaire scores based on multiple items or of the reliability of assessment across exam stations. However, as this narrative review outlines, Cronbach’s alpha or alternative reliability statistics may complement but not replace psyc…
Parasites as fish population tags and pseudoreplication problems: the case of striped red mullet Mullus surmuletus in the Spanish Mediterranean
2007
AbstractStudies of parasites as fish population tags often apply a single round of sampling to identify potential stocks or predict harvest localities. However, the lack of replication generates pseudoreplication, implicitly assuming that infection levels are more similar between samples from the same locality than between samples from different localities. We evaluated this assumption in the case of the striped red mullet Mullus surmuletus in three localities of the Spanish Mediterranean separated by c. 300 km. Samples of 25 fish of similar size were collected in each locality in the summer and autumn of two consecutive years. Prevalence and abundance of three long-lived parasite taxa diff…
Slow and fast evolving endosymbiont lineages: positive correlation between the rates of synonymous and nonsynonymous substitution
2015
The availability of complete genome sequences of bacterial endosymbionts with strict vertical transmission to the host progeny opens the possibility to estimate molecular evolutionary rates in different lineages and understand the main biological mechanisms influencing these rates. We have compared the rates of evolution for non-synonymous and synonymous substitutions in nine bacterial endosymbiont lineages, belonging to four clades (Baumannia, Blochmannia, Portiera, and Sulcia). The main results are the observation of a positive correlation between both rates with differences among lineages of up to three orders of magnitude and that the substitution rates decrease over long endosymbioses.…
Mode of selection and experimental evolution of antiviral drugs resistance in vesicular stomatitis virus
2004
Abstract The possession of an antiviral resistance mutation benefits a virus when the corresponding antiviral is present. But does the resistant virus pay a fitness cost when the antiviral is absent? Would an evolutionary history of association between a genotype and a resistance mutation overcome this cost by changes compensating the harmful side-effect of resistance mutations? Are combined therapies more effective against the rise of resistant viruses or against evolutionary compensations? To explore all these questions, we took an experimental evolution approach. After selecting vesicular stomatitis virus (VSV) populations able to replicate under increasing concentrations of ribavirin an…