Bid chimeras indicate that most BH3-only proteins can directly activate Bak and Bax, and show no preference for Bak versus Bax

The mitochondrial pathway of apoptosis is initiated by Bcl-2 homology region 3 (BH3)-only members of the Bcl-2 protein family. On upregulation or activation, certain BH3-only proteins can directly bind and activate Bak and Bax to induce conformation change, oligomerization and pore formation in mitochondria. BH3-only proteins, with the exception of Bid, are intrinsically disordered and therefore, functional studies often utilize peptides based on just their BH3 domains. However, these reagents do not possess the hydrophobic membrane targeting domains found on the native BH3-only molecule. To generate each BH3-only protein as a recombinant protein that could efficiently target mitochondria, we developed recombinant Bid chimeras in which the BH3 domain was replaced with that of other BH3-only proteins (Bim, Puma, Noxa, Bad, Bmf, Bik and Hrk). The chimeras were stable following purification, and each immunoprecipitated with full-length Bcl-xL according to the specificity reported for the related BH3 peptide. When tested for activation of Bak and Bax in mitochondrial permeabilization assays, Bid chimeras were ~1000-fold more effective than the related BH3 peptides. BH3 sequences from Bid and Bim were the strongest activators, followed by Puma, Hrk, Bmf and Bik, while Bad and Noxa were not activators. Notably, chimeras and peptides showed no apparent preference for activating Bak or Bax. In addition, within the BH3 domain, the h0 position recently found to be important for Bax activation, was important also for Bak activation. Together, our data with full-length proteins indicate that most BH3-only proteins can directly activate both Bak and Bax.

Examining customer evaluations across different self-service technologies

Purpose – This study aims to examine the influence of different self-service technologies (SSTs) on customer satisfaction with and continued usage of SSTs. Specifically, it compares an interactive voice response (IVR) SST and an online SST from the same provider to assess how to manage these parallel SSTs.

Design/methodology/approach – A tracking study was used, beginning with a survey of n = 957 SST users to test a model pertaining to SST satisfaction across IVR and online SSTs. These SST users were then tracked over 12 months. The association between customer satisfaction with and continued usage of the SSTs was examined using behavioural data from the service provider.

Findings – While the overall model was found to be valid across both types of SSTs, perceptions of factors including ease of use, perceived control and reliability differed for IVR and online SSTs. Satisfaction with SSTs is linked with users’ continued use of SSTs, but is not a barrier to users’ adoption of newer SST forms.

Research limitations/implications – Highlighting the rapid developments in this field, a new SST was introduced by the provider to respondents during the 12-month tracking period, thus complicating the results. Further studies could include the customer purpose for using SSTs as a variable.

Practical implications – The findings offer support for organisations offering a suite of SSTs, even if they serve the same purpose. Customers evaluate SST types differently, and even satisfied SST users switch to different SSTs when they become available. Allowing customers to choose the SST that best suits them appears to be good practice.

Originality/value – This study develops a comprehensive model of customer SST satisfaction that is used to undertake a comparison of two different types of SSTs, which has been missing from prior research.

Preference relation-based markov random fields

A preference relation-based Top-N recommendation approach, PrefMRF, is proposed to capture both the second-order and the higher-order interactions among users and items. Traditionally Top-N recommendation was achieved by predicting the item ratings fi rst, and then inferring the item rankings, based on the assumption of availability of explicit feed-backs such as ratings, and the assumption that optimizing the ratings is equivalent to optimizing the item rankings. Nevertheless, both assumptions are not always true in real world applications. The proposed PrefMRF approach drops these assumptions by explicitly exploiting the preference relations, a more practical user feedback. Comparing to related work, the proposed PrefMRF approach has the unique property of modeling both the second-order and the higher-order interactions among users and items. To the best of our knowledge, this is the first time both types of interactions have been captured in preference relation-based method. Experiment results on public datasets demonstrate that both types of interactions have been properly captured, and signifi cantly improved Top-N recommendation performance has been achieved.

Unifying approaches to consensus across different preference representations

© 2015 Elsevier B.V. All rights reserved. Consensus measures can be useful in group decision making problems both to guide users toward more reasonable judgments and to give an overall indication of the support for the final decision. The level of consensus between decision makers can be measured in contexts where preferences over alternatives are expressed either as evaluations or scores, pairwise preferences, and weak orders, however these different representations often call for different approaches to consensus measurements. In this paper, we look at the distance metrics used to construct consensus measures in each of these settings and how consistent these are for preference profiles when they are converted from one representation to another. We develop some methods for consistent approaches across decision making settings and provide an example to help investigate differences between some of the commonly used distances.

Construction and aggregation of preference relations based on fuzzy partial orders

In group decision-making problems it is common to elicit preferences from human experts in the form of pairwise preference relations. When this is extended to a fuzzy setting, entries in the pairwise preference matrix are interpreted to denote strength of preference, however once logical properties such as consistency and transitivity are enforced, the resulting preference relation requires almost as much information as providing raw scores or a complete order over the alternatives. Here we instead interpret fuzzy degrees of preference to only apply where the preference over two alternatives is genuinely fuzzy and then suggest an aggregation procedure that minimizes a generalized Kemeny distance to the nearest complete or partial order. By focusing on the fuzzy partial order, the method is less affected by differences in the natural scale over which an expert expresses their preference, and can also limit the influence of extreme scores.

Preference for feeding at habitat edges declines among juvenile blue crabs as oyster reef patchiness increases and predation risk grows

Both habitat patchiness and behaviorally-mediated indirect effects (BMIEs; predator- induced changes in prey behavior that affect the prey's resources) are important in many food webs, but the relationships between these 2 factors have yet to be investigated. To explore effects of habitat patchiness and variation in perceived risk of predation on food-web dynamics, we conducted a factorial experiment in a model aquatic food chain of predator-prey-resource using 2 contrasting predators (adult blue crab Callinectes sapidus and toad fish Opsanus tau), juvenile blue crab as prey, and mussel Geukensia demissa as resource. Both predator presence and habitat patchiness influenced the prey's preference for consuming resources at patch edges instead of interiors. The preference of prey for consuming resources at habitat edges was 4 times stronger in continuous oyster reef habitat than in smaller habitat patches. This suggests that interior resources in continuous habitat experience a refuge from consumption, but this refuge is largely lost in patchy habitat. The mere presence of predators reduced the prey's preference for consuming resources at habitat edges. This BMIE was significant for the ambush predator (toadfish) and the treatment containing both predators, but not for the actively hunting predator (adult blue crab). We conclude that habitat patchiness and predator presence can jointly affect resource distribution by inducing shifts in prey foraging behavior, revealing a need to incorporate BMIEs into habitat fragmentation studies. This conclusion has broad and growing relevance as anthropogenic factors increasingly modify predator abundances and fragment coastal habitats. © Inter-Research 2012.

Effects of salt and fat combinations on taste preference and perception

Fat and salt are a common and attractive combination in food and overconsumption of either is associated with negative health outcomes. The major aim was to investigate contributions and interactions of salt and fat on taste pleasantness and perception. The minor aim was to investigate individual fat taste sensitivity (detection threshold of oleic acid [C18:1]) on pleasantness for fat. In a complete factorial design, 49 participants (18-54 years, 12 males) tasted tomato soups with 4 different fat concentrations (0-20%) and 5 different salt concentrations (0.04-2.0%). The preferred concentration and the discrimination ability for both fat and salt were determined by ranking tests. Results show that salt and fat affected pleasantness separately (P < 0.01), with salt having the strongest effect. Fat concentrations 0%, 5%, and 10% did not differ in pleasantness, whereas 20% was less pleasant (P < 0.05). There were no interactions for fat and salt on pleasantness or saltiness and fattiness intensity. Fat taste sensitive participants preferred lower fat concentrations than less sensitive participants (P = 0.008). In conclusion, the strong effect of salt on pleasantness in this study suggests that salt, rather than fat, play a major role in the attraction to savory fatty foods.

Recovering from other-customer-caused failure: the effect on focal customer complaining

In the high-contact restaurant context, customers frequently “overstay,” which negatively influences focal customers waiting for tables. We examine service recovery of this failure, otherwise termed an other-customer-caused failure (OCCF) by restaurants, and its influence on focal customer complaint intentions to the organization, namely vent and voice. OCCFs are commonplace and can have a damaging effect on service organizations, and thus need to be managed; yet empirical examination of their recovery is scarce. We address this by testing the effect of the recovery actions of wait comfort, service-worker effort, and apology on focal customers’ vent and voice complaint intentions. We found that these recovery actions interact complexly. Wait comfort is obligatory in reducing customer complaints, while effort and apology are substitutable when a comfortable wait is provided. This is an important contribution, as wait comfort has not previously been examined as a recovery action.

Crowdsourcing customer needs for product design using text analytics

In product design and engineering, identifying customer needs is the foundation for designing and producing a successful product. Traditionally, a range of techniques have been employed to elicit customer needs. A relatively new technique for identifying customer needs is ‘crowdsourcing’. An emerging area of research is the crowdsourcing of customer needs from online product review sites. This paper proposes a simple process for crowdsourcing customer needs for product design using text analytics. The analysis/visualization method is presented in detail. The text content of online customer reviews for a popular product is collected and processed using text analytics software. A published case study identifying expressed customer needs for the same generic product, collected via conventional means, is used to successfully validate the findings from the text analytics method.

An empirical study of user perceived usefulness and preference of open learner model visualisations

Many higher education institutions have reformed their academic programmes to adopt unit learning outcomes. It is essential for effective learning management tools to support this fundamental transformation. We see the need for a tool that provides visualisations of Open Learner Models (OLM) and associated e-portfolio content to guide students in achieving intended learning outcomes, help evidence their learning andkeep them engaged in their study. OLMs surface the relationship between learning activities and tasks, formative and summativeassessment, and intended learning outcomes. We have developedand validated a set of candidate visualisations for such OLMs. We report key findings from our study in terms of potential users’ feedback on our tool’s support for tracking learning progress against learning outcomes. Our findings can inform and refine learning management systems.

Exploring psychometric properties of the SF-6D, a preference-based health-related quality of life measure, in the context of spinal cord injury

PURPOSE: The validity of the SF-6D, a preference-based measure of health-related quality of life, is not well explored in the context of spinal cord injury (SCI). The aim of this analysis was to assess appropriate measurement properties of the SF-6D in a sample of individuals living with SCI. METHODS: Longitudinal data from the Rick Hansen Spinal Cord Injury Registry were used. Responses to the 36-item short-form health survey were transformed into SF-6D utility scores. We investigated practicality, floor and ceiling effects, and responsiveness to change. Responsiveness to change was explored using three different anchors that reflected changes in self-reported health, functional independence, and life satisfaction. Discriminative validity was assessed by ten a priori defined hypotheses, with a distinction made between 'strong' and 'weak' hypotheses. RESULTS: Three hundred and fifty-eight individuals with SCI were included in this analysis. Practicality was deemed acceptable based on a completion rate of 94%. The SF-6D showed low responsiveness to detect important health changes over time, and differences in responsiveness were found between individuals with paraplegia and tetraplegia. All five strong hypotheses and three weak hypotheses were confirmed. CONCLUSION: The SF-6D demonstrated good practicality and discriminative validity in this sample. The failure to detect self-reported and clinically important health changes requires further consideration. Comparative performance of the SF-6D (i.e., how the SF-6D performs against other preference-based measures) is unknown in the SCI context and requires further research.