The dependent variable in social media use

What is the dependent variable in social media use? From a research perspective, this is a pertinent question to help explain and understand the behaviors that underpin the widespread adoption and use of social media throughout society. From a practical
perspective, the question is relevant for social media technology providers, for businesses that use social media, and community organizations that turn towards social media to reach out to their constituents. We propose the construct 'sense of community' as the dependent variable, which is reflected in four sub-constructs related to the behaviors of social media users. These behaviors are information seeking, hedonic activities, sustaining of strong ties and extending weak ties. Empirical evidence for these constructs comes from a survey of social media use by 18-25 year-olds in Indonesia, a ,country with exceptionally high utilization of social media. We outline practical implications of the  findings and areas for further theoretical development.

Volume, intensity, and timing of muscle power potentiation are variable

Whereas muscle potentiation is consistently demonstrated with evoked contractile properties, the potentiation of functional and physiological measures is inconsistent. The objective was to compare a variety of conditioning stimuli volumes and intensities over a 15-min recovery period. Twelve volleyball players were subjected to conditioning stimuli that included 10 repetitions of half squats with 70% of 1-repetition maximum (RM) (10 × 70), 5 × 70, 5 × 85, 3 × 85, 3 × 90, 1 × 90, and control. Jump height, power, velocity, and force were measured at baseline, 1, 3, 5, 10, and 15 min. Data were analysed with a 2-way repeated measure ANOVA and magnitude-based inferences. The ANOVA indicated significant decreases in jump height, power, and velocity during recovery. This should not be interpreted that no potentiation occurred. Each dependent variable reached a peak at a slightly different time: peak jump height (2.8 ± 2.3 min), mean power (3.6 ± 3.01 min), peak power (2.5 ± 1.8 min), and peak velocity (2.5 ± 1.8 min). Magnitude-based inference revealed that both the 5 × 70 and 3 × 85 protocol elicited changes that exceeded 75% likelihood of exceeding the smallest worthwhile change (SWC) for peak power and velocity. The 10 × 70 and the 5 × 70 had a substantial likelihood of potentiating peak velocity and mean power above the SWC, respectively. Magnitude-based inferences revealed that while no protocol had a substantial likelihood of potentiating the peak vertical jump, the 5 × 70 had the most consistent substantial likelihood of increasing the peak of most dependent variables. We were unable to consistently predict if these peaks occurred at 1, 3, or 5 min poststimulation, though declines after 5 min seems probable.

Spatial prediction of rufous bristlebird habitat in a coastal heathland: a GIS-based approach

1. To develop a conservation management plan for a species, knowledge of its distribution and spatial arrangement of preferred habitat is essential. This is a difficult task, especially when the species of concern is in low   abundance. In south-western Victoria, Australia, populations of the rare rufous bristlebird Dasyornis broadbenti are threatened by fragmentation of suitable habitat. In order to improve the conservation status of this species, critical habitat requirements must be identified and a system of corridors must be established to link known populations. A predictive spatial model of rufous bristlebird habitat was developed in order to identify critical areas requiring preservation, such as corridors for dispersal.
2. Habitat models generated using generalized linear modelling techniques can assist in delineating the specific habitat requirements of a species. Coupled with geographic information system (GIS) technology, these models can be extrapolated to produce maps displaying the spatial configuration of suitable habitat.
3. Models were generated using logistic regression, with bristlebird presence or absence as the dependent variable and landscape variables, extracted from both GIS data layers and multispectral digital imagery, as the predictors. A multimodel inference approach based on Akaike’s information criterion was used and the resulting model was applied in a GIS to extrapolate predicted likelihood of occurrence across the entire area of concern. The predictive performance of the selected model was evaluated using the receiver operating characteristic (ROC) technique. A hierarchical partitioning protocol was used to identify the predictor variables most likely to influence variation in the dependent variable. Probability of species presence was used as an index of habitat suitability.
4. Negative associations between rufous bristlebird presence and  increasing elevation, 'distance to cree', 'distance to coast' and sun index were evident, suggesting a preference for areas relatively low in altitude, in close proximity to the coastal fringe and drainage lines, and receiving less direct sunlight. A positive association with increasing habitat complexity also suggested that this species prefers areas containing high vertical density of vegetation.
5. The predictive performance of the selected model was shown to be high (area under the curve 0·97), indicating a good fit of the model to the data. Hierarchical partitioning analysis showed that all the variables considered had significant  independent contributions towards explaining the variation in the dependent variable. The proportion of the total study area that was predicted as suitable habitat for the rufous bristlebird (using probability of occurrence at a ≥0·5 level ) was 16%.
6. Synthesis and applications. The spatial model clearly delineated areas predicted as highly suitable rufous bristlebird habitat, with evidence of potential corridors linking coastal and inland populations via gullies. Conservation of this species will depend on management actions that protect the critical habitats identified in the model. A multi-scale  approach to the modelling process is recommended whereby a spatially explicit model is first generated using landscape variables extracted from a GIS, and a second model at site level is developed using fine-scale habitat variables measured on the ground. Where there are constraints on the time and cost involved in measuring finer scale variables, the first step alone can be used for conservation planning.

Landscape characteristics associated with species richness and occurrence of small native mammals inhabiting a coastal heathland: a spatial modelling approach

In the coastal region of south-western Victoria, Australia, populations of native small mammal species are restricted to patches of suitable habitat in a highly fragmented landscape. The size and spatial arrangement of these patches is likely to influence both the occupancy and richness of species at a location. Geographic Information System (GIS)-based habitat models of the species richness of native small mammals, and individual species  occurrences, were developed to produce maps displaying the spatial  configuration of suitable habitat. Models were generated using either generalised linear Poisson regression (for species richness) or logistic regression (for species occurrences) with species richness or  presence/absence as the dependent variable and landscape variables, extracted from both GIS data layers and multi-spectral digital imagery, as the predictor variables. A multi-model inference approach based on the Akaike Information Criterion was used and the resulting model was applied in a GIS framework to extrapolate predicted richness/likelihood of occurrence across the entire area of the study. A negative association between species  richness and elevation, habitat complexity and sun index indicated that richness within the study area decreases with increasing altitude, vertical vegetation structure and exposure to solar radiation. Landform  characteristics were important (to varying degrees) in determining habitat occupancy for all of the species examined, while the influence of habitat complexity was important for only one of the species. Performance of all but one of the models generated using presence/absence data was high, as indicated by the area under the curve of a receiver-operating characteristic plot. The effective conservation of the small mammal species in the area of concern is likely to depend on management actions that promote the protection of the critical habitats identified in the models.

Modelling habitat suitability of the swamp antechinus (Antechinus minimus maritimus) in the coastal heathlands of southern Victoria, Australia

In recent years, predictive habitat distribution models, derived by combining multivariate statistical analyses with Geographic Information System (GIS) technology, have been recognised for their utility in conservation planning. The size and spatial arrangement of suitable habitat can influence the long-term persistence of some faunal species. In southwestern Victoria, Australia, populations of the rare swamp antechinus (Antechinus minimus maritimus) are threatened by further fragmentation of suitable habitat. In the current study, a spatially explicit habitat suitability model was developed for A. minimus that incorporated a measure of vegetation structure. Models were generated using logistic regression with species presence or absence as the dependent variable and landscape variables, extracted from both GIS data layers and multi-spectral digital imagery, as the predictors. The most parsimonious model, based on the Akaike Information Criterion, was spatially extrapolated in the GIS. Probability of species presence was used as an index of habitat suitability. A negative association between A. minimus presence and both elevation and habitat complexity was evidenced, suggesting a preference for relatively low altitudes and a vegetation structure of low vertical complexity. The predictive performance of the selected model was shown to be high (91%), indicating a good fit of the model to the data. The proportion of the study area predicted as suitable habitat for A. minimus (Probability of occurrence greater-or-equal, slanted0.5) was 11.7%. Habitat suitability maps not only provide baseline information about the spatial arrangement of potentially suitable habitat for a species, but they also help to refine the search for other populations, making them an important conservation tool.

The relationship between child sexual abuse and academic achievement in a sample of adolescent psychiatric inpatients

Objectives:
To examine the relationship between sexual abuse and academic achievement in an adolescent inpatient psychiatric population. Individual factors expected to influence this relationship were measured to explore the way they each interacted with sexual abuse and its relationship to academic achievement.

Method:
Eighty-one adolescent psychiatric inpatients participated in the study (aged 12–18 years: M = 16.0). Participants were administered tests of academic achievement (dependent variable) and intelligence, and completed a number of self-report measures of their experience of different types of maltreatment, their perception of the parenting they received, socio-economic status, substance abuse, and psychopathology.

Results:
Hierarchical regression analysis revealed that intelligence was the main predictor of academic achievement (uniquely explaining 26% of the variance). A number of interaction effects were also significant indicating that intelligence, substance abuse, internalizing behavior problems, externalizing behavior problems all influenced the relationship between sexual abuse and academic achievement.

Estimating the effects of energy imbalance on changes in body weight in children

BACKGROUND: Estimating changes in weight from changes in energy balance is important for predicting the effect of obesity prevention interventions. OBJECTIVE: The objective was to develop and validate an equation for predicting the mean weight of a population of children in response to a change in total energy intake (TEI) or total energy expenditure (TEE). DESIGN: In 963 children with a mean (+/-SD) age of 8.1 +/- 2.8 y (range: 4-18 y) and weight of 31.5 +/- 17.6 kg, TEE was measured by using doubly labeled water. Log weight (dependent variable) and log TEE (independent variable) were analyzed in a linear regression model with height, age, and sex as covariates. It was assumed that points of dynamic balance, called "settling points," occur for populations wherein energy is in balance (TEE = TEI), weight is stable (ignoring growth), and energy flux (EnFlux) equals TEE. RESULTS: TEE (or EnFlux) explained 74% of the variance in weight. The unstandardized regression coefficient was 0.45 (95% CI: 0.38, 0.51; R(2) = 0.86) after including covariates. Conversion into proportional changes (time(1) to time(2)) gave the equation (weight(2)/weight(1)) = (EnFlux(2)/EnFlux(1))(0.45). In 3 longitudinal studies (n = 212; mean follow-up of 3.4 y), the equation predicted the mean follow-up measured weight to within 0.5%. CONCLUSIONS: The relation of EnFlux with weight was positive, which implied that a high TEI (rather than low physical activity and low TEE) was the main determinant of high body weight. Two populations of children with a 10% difference in mean EnFlux would have a 4.5% difference in mean weight.

Can experiential learning improve emotional intelligence and can that, in turn, improve the work performance of middle managers?

A group of middle managers in the Australian arm of a large Global company participated in a program of experiential leadership training over a period of one year. One aim of the program was increased interpersonal skills and awareness. Change was measured using a mixed quantitative and qualitative longitudinal design. Pre and post-training measures of emotional intelligence were obtained using the EIQ (Dulewicz & Higgs, 2000) and compared with content analysis of journals kept by participants during the program. The dependent variable was measured by pre and post training measures of work performance. Findings are discussed in terms of their implications for management development as well as for further research.

Moving a unit online: a quantitative evaluation of student repsonses

In 2005, a unit was converted to ‘wholly online’ delivery mode, where all teaching occurred online. Student evaluation survey data for 2005 suggested that students rated many aspects of the wholly online unit delivery significantly lower than previously. For 2006, ten percent of the unit marks were dedicated to an assessed assignment activity based around an online discussion area. Based on student evaluation items common to the preand post-2006 period, overall student satisfaction with the unit returned to the same levels as prior to the introduction of wholly online delivery. These findings suggest that careful thought, but not necessarily major changes, may be required to avoid student disillusionment and maximise student learning outcomes when moving an existing unit to wholly online delivery. During 2005 and 2006, the same unit was included in a large survey to gauge students’ perceptions of studying wholly online units. The sub-set of respondents relating to this unit was found to have a good demographic match to the total unit enrolment. The survey included the following question item, ‘39: How satisfied have you been with this unit being offered wholly online?’, as an overall measure of student satisfaction with studying the unit in wholly online mode. Multivariate linear regression analysis was conducted with survey item 39 as the dependent variable. While the resultant regression model should not be interpreted literally as a formula for student satisfaction, it does suggest some areas for action to improve student satisfaction with studying this unit in wholly online mode.

Estimating the changes in energy flux that characterize the rise in obesity prevalence

Background: The daily energy imbalance gap associated with the current population weight gain in the obesity epidemic is relatively small. However, the substantially higher body weights of populations that have accumulated over several years are associated with a substantially higher total energy expenditure (TEE) and total energy intake (TEI), or energy flux (EnFlux = TEE = TEI).
Objective: The objective was to develop an equation relating EnFlux to body weight in adults for estimating the rise in EnFlux associated with the obesity epidemic.
Design: Multicenter, cross-sectional data for TEE from doubly labeled water studies in 1399 adults aged 5.9 ± 18.8 y (mean ± SD) were analyzed in linear regression models with natural log (ln) weight as the dependent variable and ln EnFlux as the independent variable, adjusted for height, age, and sex. These equations were compared with those for children and applied to population trends in weight gain.
Results: ln EnFlux was positively related to ln weight (β = 0.71; 95% CI: 0.66, 0.76; R2 = 0.52), adjusted for height, age, and sex. This slope was significantly steeper than that previously described for children (β = 0.45; 95% CI: 0.38, 0.51).
Conclusions: This relation suggests that substantial increases in TEI have driven the increases in body weight over the past 3 decades. Adults have a higher proportional weight gain than children for the same proportional increase in energy intake, mostly because of a higher fat content of the weight being gained. The obesity epidemic will not be reversed without large reductions in energy intake, increases in physical activity, or both.

Higher education, real income and real investment in China : evidence from Granger causality tests

This paper employs cointegration and error-correction modelling to test the causal relationship between real income, real investment and tertiary education using data for the People's Republic of China over the period 1952-1999. To proxy tertiary education we use higher education enrolments and higher education graduates in alternative empirical specifications. One of the paper's main findings is that real income, real investment and tertiary education are cointegrated when real investment is the dependent variable, but are not cointegrated when either tertiary education or real income is the dependent variable. We also extend the in-sample analysis to examine the decomposition of variance and impulse response functions.

Design-related bias in hospital fall risk screening tool predictive accuracy evaluations: systematic review and meta-analysis.

Introduction: Fall risk screening tools are frequently used as a part of falls prevention programs in hospitals. Design-related bias in evaluations of tool predictive accuracy could lead to overoptimistic results, which would then contribute to program failure in practice.

Methods: A systematic review was undertaken. Two blind reviewers assessed the methodology of relevant publications into a four-point classification system adapted from multiple sources. The association between study design classification and reported results was examined using linear regression with clustering based on screening tool and robust variance estimates with point estimates of Youden Index (= sensitivity + specificity - 1) as the dependent variable. Meta-analysis was then performed pooling data from prospective studies.

Results: Thirty-five publications met inclusion criteria, containing 51 evaluations of fall risk screening tools. Twenty evaluations were classified as retrospective validation evaluations, 11 as prospective (temporal) validation evaluations, and 20 as prospective (external) validation evaluations. Retrospective evaluations had significantly higher Youden Indices (point estimate [95% confidence interval]: 0.22 [0.11, 0.33]). Pooled Youden Indices from prospective evaluations demonstrated the STRATIFY, Morse Falls Scale, and nursing staff clinical judgment to have comparable accuracy.

Discussion: Practitioners should exercise caution in comparing validity of fall risk assessment tools where the evaluation has been limited to retrospective classifications of methodology. Heterogeneity between studies indicates that the Morse Falls Scale and STRATIFY may still be useful in particular settings, but that widespread adoption of either is unlikely to generate benefits significantly greater than that of nursing staff clinical judgment.

The influence of Sport Education on student motivation in physical education

Background: Physical educators are faced with trying to provide motivating and enjoyable experiences in physical education. Sport Education is an instructional model that aims to provide positive motivational sport experiences by simulating the features of authentic sport. Research support for Sport Education is positive, however, the effects on student motivation and the motivational climate are not well understood.

Purpose: To investigate the influence of the Sport Education model on student motivation (intrinsic/extrinsic motivation, goal orientations, and perceived motivational climate) in secondary physical education.

Setting: Six classes were selected according to teacher and class availability in the sports of soccer, hockey, and football codes in a co-educational government school.

Participants: Participants were 115 (male = 97, female = 18) Year-8 students (aged 13-14 years), in a Sport Education condition (n = 41) and a Traditional condition (n = 74).

Measures: At pre- and post-test, all participants completed three questionnaires: the Intrinsic Motivation Inventory, the Task and Ego Orientation in Sport Questionnaire, and the Perceived Motivational Climate in Sport Questionnaire.

Intervention: Participants completed either a Sport Education condition or a Traditional condition for one double period (100 minutes) one day per week for 10 weeks (Sport Education condition) or for five weeks (Traditional condition). The Sport Education condition incorporated six distinctive features: seasons, affiliation, formal competition, record keeping, festivity, and a culminating event. The Traditional condition used whole-group instruction led by the teacher.

Research design: The study used a non-equivalent control group design with pre- and post-test procedures. The independent variable was teaching condition and the dependent variable was student motivation (assessed by intrinsic motivation, goal orientations, and motivational climate). The groups were already established and selected for convenience purposes.

Data collection and analysis: Participants completed pre-test measures and then participated in their pre-established classes. Post-test measures were completed in the last class in each condition. A reliability analysis on measures was conducted using Cronach's alphas. A pre-test manipulation check was performed to check for any initial differences in motivation. To compare the difference in changes between conditions on motivation, a series of 2 times 2 repeated measures analyses of variance were conducted. A comparison of the relationship between motivation measures was conducted using Pearson's product moment correlation coefficients.

Findings: There was a significant difference between the conditions on changes in perceived competence, task orientation, and mastery climate, with the Traditional condition decreasing significantly from pre- to post-test compared with the Sport Education condition. There were no significant differences on interest/enjoyment, effort/importance, pressure/tension, ego orientation, or performance climate. A mastery climate was positively related to task orientation and intrinsic motivation and a performance climate was related to ego orientation.

Conclusions: The Sport Education condition was more successful in maintaining high levels of intrinsic motivation, task orientation, and mastery climate than the Traditional condition. That is, the Traditional condition was associated with a decrease in adaptive aspects of motivation for students, whereas the Sport Education condition maintained existing levels of motivation.

Influence of an adventure learning program, using group adventure initiative tasks, on participant self-esteem

The purpose of this study was to assess the influence of an adventure learning program, based on participation in group adventure initiative tasks (GAITs), on participant self-esteem and, further, to examine any associated gender differences in the dependent variable. The study took place within the framework of the 'Group Dynamics in Action' unit offered at the University of South Australia, Underdale Campus, in semester 2, 1994. The course included participation in group adventure initiative tasks, the identification and examination of group dynamic processes, the investigation of individual roles within the small group and the review of these processes in the group setting. The program also included an experience on a high ropes course. Both quantitative and qualitative data was gathered to gain insight into gender differences and their relationship to the dependent variable and also to provide insight into any discrepancy in outcomes between males and females with regard to participation in group adventure initiative tasks. The sample set of participants was drawn from undergraduate students studying at the University of South Australia in the Bachelor of Teaching (Primary), Bachelor of Education (Secondary Physical Education Teaching) and Bachelor of Applied Science (Exercise and Sport Science) courses. Subjects were assigned to either experimental or control conditions and the experimental group were then randomly assigned to one of three treatment groups. Sixty one (N = 61) male and female subjects were tested pre and post-treatment period. Psychological tests included the Coopersmith Self Esteem Inventory (Coopersmith 1981) and an adaptation of Coopersmith's Behaviour Rating Form (Coopersmith 1967). Qualitative data was gathered using Kuhn's Twenty Statements Test (Kuhn and McPartland 1954), a self-esteem questionnaire, observations made by the researcher and other staff about subjects interactions and from weekly journals kept by subjects throughout the treatment. The duration of the treatment period was 14 weeks consisting of 14, 2 hour seminars.

An empirical analysis of Fiji’s import demand function

Purpose – This paper aims to estimate a disaggregated import demand model for Fiji using relative prices, total consumption, investment expenditure and export expenditure variables for the period 1970 to 2000.

Design/methodology/approach – The recently developed bounds testing approach to cointegration to test for a long run relationship is used, while the autoregressive distributed lag model is used to estimate short run and long run elasticities. These methodologies are shown to perform well in small sample sizes, particularly given that the bounds F-test critical values for small sample sizes generated by Narayan in 2004 and 2005 are used.

Findings – Amongst the key results it is found: a long run cointegration relationship among the variables when import demand is the dependent variable; and import demand to be inelastic and statistically significant at the 1 per cent level with respect to all the explanatory variables in both the long-run and the short-run.

Originality/value – The disaggregated import demand model estimated here provides a complete picture of the determinants of Fiji's imports. This model can be used by Fijian policy makers to draw pertinent policies and forecast import demand for Fiji.