Effect of ECG-derived respiration (EDR) on modeling ventricular repolarization dynamics in different physiological and psychological conditions

Ventricular repolarization dynamics is an important predictor of the outcome in cardiovascular diseases. Mathematical modeling of the heart rate variability (RR interval variability) and ventricular repolarization variability (QT interval variability) is one of the popular methods to understand the dynamics of ventricular repolarization. Although ECG derived respiration (EDR) was previously suggested as a surrogate of respiration, but the effect of respiratory movement on ventricular repolarization dynamics was not studied. In this study, the importance of considering the effect of respiration and the validity of using EDR as a surrogate of respiration for linear parametric modeling of ventricular repolarization variability is studied in two cases with different physiological and psychological conditions. In the first case study, we used 20 young and 20 old healthy subjects’ ECG and respiration data from Fantasia database at Physionet to analyze a bivariate QT–RR and a trivariate QT–RR–RESP or QT–RR–EDR model structure to study the aging effect on cardiac repolarization variability. In the second study, we used 16 healthy subjects’ data from drivedb (stress detection for automobile drivers) database at Physionet to do the same analysis for different psychological condition (i.e., in stressed and no stress condition). The results of our study showed that model having respiratory information (QT–RR–RESP and QT–RR–EDR) gave significantly better fit value (p < 0.05) than that of found from the QT–RR model. EDR showed statistically similar (p > 0.05) performance as that of respiration as an exogenous model input in describing repolarization variability irrespective of age and different mental conditions. Another finding of our study is that both respiration and EDR-based models can significantly (p < 0.05) differentiate the ventricular repolarization dynamics between healthy subjects of different age groups and with different psychological conditions, whereas models without respiration or EDR cannot distinguish between the groups. These results established the importance of using respiration and the validity of using EDR as a surrogate of respiration in the absence of respiration signal recording in linear parametric modeling of ventricular repolarization variability in healthy subjects.

Towards institution-wide online teaching and learning systems: trends, drivers and issues

Universities worldwide are consolidating and enhancing their commitments to various models of e-learning. These activities are leading to the adoption of corporate-wide e-learning systems, and accompanying changes in structures, processes and infrastructure requirements. The professed ideal is to identify narrowly defined corporate IT solutions which can deliver the full range of educational, administrative and student support features to meet the organisational need to expand e-learning activities globally. The trend seems to be away from locally driven and controlled IT development and adoption towards investments in Instructional Management Systems (IMS). In reality, however, universities generally are developing and using a broader array of solutions to meet their needs than may be deemed desirable under a more centralised, corporatised IT approach. This paper examines these trends by analysing the drivers shaping corporate approaches to IT implementation, and reflects critically on some of the educational, economic and organisational tensions and issues evident in institutional approaches to establishing such systems. The paper highlights the ongoing need for innovative, dynamic organisational solutions to progress the e-learning agenda, and the thoughtful reconciliation of centralised and decentralised approaches to achieving desired ends.

Measuring consumer involvement : a test of the automobile involvement scale

This study empirically investigated consumer involvement with a product class. Data was collected from 178 vehicle buyers. Reliability and factor analyses investigated the structure of the Bloch (1981) instrument and the dimensions underlying involvement. In terms of replication, the results suggest the reduced-item version of the instrument previously proposed by Shimp and Sharma (1983) is reliable and is a less excessive measurement instrument. Similar dimensions underlying involvement with the product class are reported here. The study extends previous work by obtaining similar results in a different cultural setting, producing findings from a more relevant sample, applying an additional method of data collection, and suggesting that the underlying dimensions may be temporally stable.

At home on the road? Can drivers' relationships with their cars be associated with territoriality?

The current research explores the relationship between people and their cars within the framework of Altman's theory of human territoriality. It further develops the research of Sandqvist by examining the descriptions given by people with differing ownership and uses of their cars and exploring the congruence between these and the characteristics used to describe human territories. Thirteen focus groups were held with young drivers between the ages of 18 and 25 years, drivers over the age of 25 who are parents of pre-license age children, drivers over the age of 25 who do not regularly transport children, and drivers of work vehicles. Analyses of discussions revealed that drivers’ descriptions of the relationship with their car could be matched with Brown and Altman's descriptions of territory types. However, variations existed both between and within individuals as to the application of the labels ‘primary’, ‘secondary’ and ‘public’ territory to the car. Implications for the understanding of road user behaviour and the further development of theory on the car as a place or an object in terms of territoriality are discussed.

Don't tate us! The impediments and drivers of branding museums

This study examines the applicability of brand orientation, and its drivers and impediments in the museum context. A multiple case study approach, with 12 institutions across two countries (United Kingdom and Australia) was carried out. Results suggest that brand orientation provides the cultural platform to retain the distinctiveness of the institution and build the symbolic representation required to remain competitive in the future.

'Social drivers' as predictors of yoghurt consumption in China

A survey of yoghurt consumption by female consumers in Beijing showed 42% consuming often, 26% occasionally and 32% never. Consumers were generally younger and more driven by materialistic values than non-consumers. "Social drivers" are presented as a 1001 for marketers to predict the use of consumer
products.

Retail internationalisation : drivers, impediments and business strategy

In light of recent changes in the international environment it is important to consider whether the drivers and impediments of retail internationalisation and the business strategy adopted have also changed. The findings from 12 qualitative interviews with UK and US retailers indicate that a variety of factors, ranging from historical precedence and investor pressures to saturation of the domestic market and foreign market attractiveness, drive retail internationalisation. In terms of impediments to foreign expansion, issues such as political and economic instability, previous experience and perceived cultural differences presented obstacles to internationalisation. Interviewees also expressed a desire for increased standardisation, while acknowledging a substantial degree of adaptation in response to cultural differences.

Revisiting retail internationalisation drivers, impediments and business strategy

Purpose: – In the light of recent changes in the international environment, the purpose of this paper is to consider whether the drivers of, and impediments to, retail internationalisation and the business strategy adopted have also changed.

Design/methodology/approach: – Interviews were conducted with 12 UK and US retailers. These exploratory data were combined with a review of the literature to explore changes in the drivers and impediments of retail internationalisation.

Findings: – Findings of this study suggest that, while a variety of factors drive retail internationalisation, profit growth is the most dominant motivator. In terms of impediments to foreign expansion, domestic market conditions were a barrier to the initiation of foreign expansion, whilst the regulatory environment and previous experiences presented obstacles in the process of internationalisation. Interviewees also expressed a desire for increased standardisation, while acknowledging the need for a substantial degree of adaptation in response to cultural differences.

Research limitations/implications: – The research findings are limited in terms of their generalisability.

Originality/value: – Much of the existing research into retail internationalisation was conducted in the 1990s. Given the substantial changes that have occurred over the past 15 years, the value of this paper lies in the updating of knowledge.

Identifying the drivers behind housing preferences of first time owners

Purpose – The purpose of this paper is to provide a rare insight into the motivation behind first-time buyers when looking to purchase their first home. The factors driving demand preferences for detached housing are constantly changing and difficult to measure, and often deemed to be a complex bundle of attributes.

Design/methodology/approach – The research in this paper is based on interviews with purchasers at a series of locations across Melbourne, Australia, who were actively seeking to purchase a home for the first time. The data were analysed using factor analysis to identify the core decision criteria in a new house that were most sought after.

Findings – The findings in this paper confirmed that “financial” issues accounted for approximately 30 percent of the actual decision by first-time buyers to purchase housing, where decisions relating to the timing and choice of housing are dependent on “site-specific” factors.

Research limitations/implications – The research in this paper is aimed specifically at first time buyers only and the influencing factors behind their purchasing decisions.

Practical implications – The paper shows that, if consideration is given to the characteristics that first-time owners are looking for, providers of new housing would be better equipped to meet this demand and maximise construction efficiency.

Originality/value – In the paper the emphasis was placed on identifying and analysing the decision criteria behind first-time buyers, which provided an invaluable insight into their concept of a suitable residence. Rather than analysing sales transactions after they have been completed, this research considers aspects of new houses that first-time owners are actively searching for, prior to making their purchase.