High Level Of Variance Research Articles

Resilience model for parents of children with cancer in mainland China-An exploratory study.

Parents have psychosocial functions that are critical for the entire family. Therefore, when their child is diagnosed with cancer, it is important that they exhibit resilience, which is the ability to preserve their emotional and physical well-being in the face of stress. The Resilience Model for Parents of Children with Cancer (RMP-CC) was developed to increase our understanding of how resilience is positively and negatively affected by protective and risk factors, respectively, in Chinese parents with children diagnosed with cancer. To evaluate the RMP-CC, the latent psychosocial variables and demographics of 229 parents were evaluated using exploratory structural equation modeling (SEM) and logistic regression. The majority of goodness-of-fit indices indicate that the SEM of RMP-CC was a good model with a high level of variance in resilience (58%). Logistic regression revealed that two demographics, educational level and clinical classification of cancer, accounted for 12% of this variance. Our results indicate that RMP-CC is an effective structure by which to develop mainland Chinese parent-focused interventions that are grounded in the experiences of the parents as caregivers of children who have been diagnosed with cancer. RMP-CC allows for a better understanding of what these parents experience while their children undergo treatment. Further studies will be needed to confirm the efficiency of the current structure, and would assist in further refinement of its clinical applications.

Combining ability of alfalfa collection accessions by components of feed and seed productivity on increased soil acidity

Assessment of the combining ability of alfalfa (Medicago sativa L., M. varia L.) collection accessions of different eco-geographical origin by components of feed and seed productivity in diallel crosses on increased soil acidity (pH 5.2–5.3) was carried out in the Department of Forage Crop Breeding of the Institute of Feeds and Agriculture of Podillia of NAAS (2012–2014).The aim and tasks of the study. Estimation of the combining ability of alfalfa collection accessions by components of feed and seed productivity in diallel crosses on increased soil acidity.Materials and methods: Forty two hybrid (F2) alfalfa populations derived by complete scheme of diallel analysis from collection accessions (Syniukha (UJ0700134, Ukraine); Regina (UJ0700031, Ukraine); Yaroslavna (UJ0700225, Ukraine); Vika (Denmark); Mega (UJ0700365, Sweden); Grіlys (Sweden) and variable Zhidrune (UJ0700699, Lithuania) were used as the study material. Effects of the general combining ability and variances of specific combining ability were determined by statistical methods of genetic analysis.Results and discussion. We selected alfalfa accessions with strong effects of the general combining ability: by stem length and dry matter yield – Grilys and Regina; by foliage amount – Syniukha, Zhidrune and Vika; by fertile tiller number – Zhidrune, Yaroslavna and Mega; by raceme number per stem – Regina and Vika; by pod number per raceme – Syniukha and Zhidrune; by seed number per pod – Yaroslavna and Vika; by 1000seed weight – Regina and Mega; by seed yield – Zhidrune and Regina. High levels of variance of the specific combining ability were inherent to: Grilys and Regina – for stem length and dry matter yield; Yaroslavna and Mega – for fertile tiller number; Regina – for raceme number per stem; Zhidrune – for pod number per raceme; Yaroslavna – for seed number per pod; Regina and Mega – for 1000seed weight. It was found that the best components of pair crosses were Zhidrune and Vika – by foliage amount; Zhidrune – by fertile tiller number; Vika – by raceme number per stem and seed number per pod; Syniukha – by pod number per raceme; Zhidrune and Regina – by seed yield.Conclusions. We assessed the combining ability of the test alfalfa collection accessions of different eco-geographical origin by the traits of feed and seed productivity in complete diallel crosses on increased soil acidity.Regina and Zhidrune were noticeable for by strong effects of the general combining ability by the majority of traits.We selected promising hybrid populations with high and medium levels of variance of the specific combining ability of parents by the majority of economically valuable traits: Zhidrune/Regina, Yaroslavna/Mega, Zhidrune/Grilys, Vika/Mega and Mega/Grilys

Risk management abilities in multimodal maritime supply chains: Visibility and control perspectives

Supply chain complexity and disintegration lead to increased uncertainty from a stakeholders’ perspective, which is emerging as one of the major challenges of risk management. The ability to identify risks has weakened, as the responsibility of supply chain risk management is handed over to outside service providers. Regardless, the risks, their visibility and their impact depend on the position of the companies in the supply chain. The actors in the chain must therefore collaborate to create effective risk management conditions. This challenging situation is especially pronounced in multimodal maritime supply chains, where the risks and actor focality are high. This paper contributes to current risk management literature by providing a holistic and systemic view of risk visibility and control in maritime supply chains. The study employs broad-based, qualitative interview data collected from actors operating in southern Finland and the Gulf of Finland as well as an expert-panel assessment of the related risk management abilities. The results show a high level of variance in the level of risk identification and visibility between the actors in question. This further suggests that collaboration in supply chain risk management is essential, as an awareness of the risks and their control mechanisms do not necessarily reside in the same company.

Web 2.0 and Communication Processes at Work: Evidence From China

Research problem: Web 2.0 applications, such as instant messengers and other social media platforms, are fast becoming ubiquitous in organizations, yet their impact on work performance is poorly understood. Research question: What is the relationship between Web 2.0 use, and work-based communication processes and outcomes in China? Literature review: Literature in the fields of information systems and media and communication research supports the value of Web 2.0 for organizations. However, how Web 2.0 can facilitate the organizational communication process and subsequently improve performance is underinvestigated. By adapting and extending the communicative ecology framework and previously published work, we developed and tested a theoretical model to investigate these impacts in the Chinese workplace. Methodology: We conducted a quantitative study using the survey method, with participants randomly selected from a panel database in China. Results and conclusions: We analyzed survey data from 179 organizational employees and found that vertical and horizontal communication contribute significantly to individual and teamwork performance, with high levels of variance explained. In this study, we provide empirical evidence of how Web 2.0 applications enable employees to reach out to collaborators and business partners, thereby boosting individual productivity and team collaboration. The study also highlights the fit between Web 2.0 and the need for organizational horizontal communication in this era of knowledge, information, and creativity. Future researchers should verify the research model in different countries, including local contextual characteristics as either independent variables or moderators.

Hand Raising Pose Detection in the Images of a Single Camera for Mobile Robot.

This paper proposes a novel method for detection of hand raising poses from images acquired from a single camera attached to a mobile robot that navigates unknown dynamic environments. Due to unconstrained illumination, a high level of variance in human appearances and unpredictable backgrounds, detecting hand raising gestures from an image acquired from a camera attached to a mobile robot is very challenging. The proposed method first detects faces to determine the region of interest (ROI), and in this ROI, we detect hands by using a HOG-based hand detector. By using the color distribution of the face region, we evaluate each candidate in the detected hand region. To deal with cases of failure in face detection, we also use a HOG-based hand raising pose detector. Unlike other hand raising pose detector systems, we evaluate our algorithm with images acquired from the camera and images obtained from the Internet that contain unknown backgrounds and unconstrained illumination. The level of variance in hand raising poses in these images is very high. Our experiment results show that the proposed method robustly detects hand raising poses in complex backgrounds and unknown lighting conditions.

Dissociating the neural mechanisms of pain consistency and pain intensity in the trigemino-nociceptive system.

Individual differences in pain perception to a standardized nociceptive input are a well-known phenomenon within pain research. Brain structures known to play a crucial role in pain modulatory processes are the rostral/subgenual anterior cingulate cortex (sACC) as well as the periaqueductal gray (PAG), which belong to the endogenous antinociceptive system. However, the exact mechanisms possibly leading to this high level of variance in pain perception are still a matter of debate. Pain perception within the trigemino-vascular system was investigated in 37 healthy volunteers using functional magnetic resonance imaging. Behavioral results show high levels of variance being inversely correlated to mean pain ratings as well as to an increase in BOLD signal intensity within the sACC. In addition, higher sACC activation was coupled with activation in the PAG the lower the level of intra-individual variance. This study gives first indications that coupled BOLD response within brain structures of the antinociceptive system seems to rather not code pain intensity within the trigemino-nociceptive system but the stability of volunteers' pain ratings. Intrinsic mechanisms may modulate the pain perception in the trigemino-vascular system, which is highly involved in headache disorders.

The Disconnect Between Summer and Winter Monarch Trends for the Eastern Migratory Population: Possible Links to Differing Drivers

The decline of the eastern population of the migratory monarch has become a topic of great concern, but has been based entirely on patterns observed in overwinter colony sizes. Less attention has been paid to population trends during other phases of the migratory cycle. Here, we present an analysis of trends using three monitoring programs, one focused on overwinter colony size and two focused on summer breeding grounds. We discovered an alarming steepening in the decline of winter colony size since 2008. However, population indices from two independent summer monitoring programs were characterized by high year-to-year variability and no statistically detectable trends over time. Despite the mismatch in summer and winter patterns, there is still an association between the yearly fluctuations between these key periods, suggesting a link in population dynamics throughout the year. Further, a suggestion of a downturn near the end of the summer time-series should be carefully tracked into the future. We discuss two possible reasons for this disconnect: 1) higher levels of variance or possibly biased sampling could weaken any statistical signal, and 2) losses during fall migration could potentially contribute to overwinter declines.

Direct encoding of orientation variance in the visual system.

Our perception of regional irregularity, an example of which is orientation variance, seems effortless when we view two patches of texture that differ in this attribute. Little is understood, however, of how the visual system encodes a regional statistic like orientation variance, but there is some evidence to suggest that it is directly encoded by populations of neurons tuned broadly to high or low levels. The present study shows that selective adaptation to low or high levels of variance results in a perceptual aftereffect that shifts the perceived level of variance of a subsequently viewed texture in the direction away from that of the adapting stimulus (Experiments 1 and 2). Importantly, the effect is durable across changes in mean orientation, suggesting that the encoding of orientation variance is independent of global first moment orientation statistics (i.e., mean orientation). In Experiment 3 it was shown that the variance-specific aftereffect did not show signs of being encoded in a spatiotopic reference frame, similar to the equivalent aftereffect of adaptation to the first moment orientation statistic (the tilt aftereffect), which is represented in the primary visual cortex and exists only in retinotopic coordinates. Experiment 4 shows that a neuropsychological patient with damage to ventral areas of the cortex but spared intact early areas retains sensitivity to orientation variance. Together these results suggest that orientation variance is encoded directly by the visual system and possibly at an early cortical stage.

Factors affecting direction and strength of patient preferences for treatment of molar teeth with nonvital pulps.

To elicit the factors affecting willingness to pay (WTP) values for the preferred options of participants for dealing with a molar tooth with a nonvital pulp, a common but difficult problem. A total of 503 patients were recruited from dental practices in the North East of England and interviewed. Their preferred treatment option for a molar tooth with a nonvital pulp (endodontics, extraction and various prosthetic restorative options) and WTP for this preferred option were elicited. Factors affecting preferred option and WTP were analysed using econometric modelling. Overall, 53% of the sample wished to save the tooth with a mean WTP of £373. The variance in WTP was high. Of those opting for extraction, the majority chose to leave a gap or have an implant. The preferred option was influenced by previous treatment experience. WTP was only influenced by having a low income. The high level of variance in WTP and its relatively unpredictable nature pose difficult questions for policy makers trying to ensure the delivery of an equitable service. For dentists, it is important not to make assumptions about patient preference and strength of preference when making decisions. Ideally, WTP values should be considered alongside effectiveness data, and those on costs, in policy making.

Latent class analysis was accurate but sensitive in data simulations

ObjectivesLatent class methods are increasingly being used in analysis of developmental trajectories. A recent simulation study by Twisk and Hoekstra (2012) suggested caution in use of these methods because they failed to accurately identify developmental patterns that had been artificially imposed on a real data set. This article tests whether existing developmental patterns within the data set used might have obscured the imposed patterns. Study Design and SettingData were simulated to match the latent class pattern in the previous article, but with varying levels of randomly generated variance, rather than variance carried over from a real data set. Latent class analysis (LCA) was then used to see if the latent class structure could be accurately identified. ResultsLCA performed very well at identifying the simulated latent class structure, even when the level of variance was similar to that reported in the previous study, although misclassification began to be more problematic with considerably higher levels of variance. ConclusionThe failure of LCA to replicate the imposed patterns in the previous study may have been because it was sensitive enough to detect residual patterns of population heterogeneity within the altered data. LCA performs well at classifying developmental trajectories.

Independent Component Analysis for Realized Volatility: Analysis of the Stock Market Crash of 2008

This paper investigates the factors that drove the U.S. equity market returns from 2007 through early 2010. The period was highlighted by volatile energy and commodity prices, the collapse of insurance and banking firms, extreme implied volatility and a subsequent rally in the overall market. To extract the driving factors, we decompose the returns of the S&P 500 sector ETFs into statistically independent signals using independent component analysis. We find that the generated factors have interesting financial interpretations and are consistent with the major economic themes of the period. We find that there are two sets of general market betas during the period along with a dominant factor for energy and materials sector. In addition, we find that the EGARCH model which accommodates asymmetric responses between returns and volatility can plausibly fit the high levels of variance during the crash. Finally, estimated correlations dropped when commodity prices moved higher, but then spiked when the S&P 500 crashed in late 2008.

The dark side of the movie. The difficult balance between risk and return

PurposeThis paper aims to analyse the risk and return trade‐off in the film industry, and to explain the managerial decisions justifying significant investments in such a risky and uncertain sector.Design/methodology/approachAn extensive dataset of movies released in US theatres over a period of 12 years along with descriptive statistics, frequency analysis and scatter plot methodology are used.FindingsThe findings highlight: a positive relationship, although with high levels of variance, between production budgets and revenues; and a random association between costs and rates of return.Practical implicationsDifferently from other commodities, whose demand can be quite accurately estimated, the success of a new film production is extremely uncertain. Therefore, the reason why major film companies have been successful over the last decades, in spite of the extreme variance that is characteristic of the industry, must be found in the management decision approach that they employ to deal with this uncertainty.Originality/valueThe paper uses statistical evidence to draw management implications, rather than only identifying the economic and financial behaviour of the firms running the film industry, in recognising that correct management decision approaches are behind the success of such an uncertain and volatile industry.

A Protein‐Interaction Array Inside a Living Cell

Cell phenotype is determined by protein network states that are maintained by the dynamics of multiple protein interactions.1 Fluorescence microscopy approaches that measure protein interactions in individual cells, such as by Forster resonant energy transfer (FRET), are limited by the spectral separation of fluorophores and thus are most suitable to analyze a single protein interaction in a given cell. However, analysis of correlations between multiple protein interactions is required to uncover the interdependence of protein reactions in dynamic signal networks. Available protein-array technologies enable the parallel analysis of interacting proteins from cell extracts, however, they can only provide a single snapshot of dynamic interaction networks. Moreover, because of the high level of variance from cell to cell in protein expression levels and reaction state, cell extracts only provide an average measure of protein interaction states and therefore the detection of the relations between proteins is blurred. As an intermediate step, a visual immunoprecipitation assay was developed that allowed direct observation of multiple, dynamic protein interactions on immobilized, distinguishable beads in cell extracts.2 A microstructuring approach allowed for analysis of the interaction of one naturally occurring receptor type with one of its interaction partners inside cells.3 To analyze multiple protein interactions inside a single living cell, multiple receptors must be arranged in a defined pattern to distinguish their identity. Herein, we developed a general strategy to generate protein arrays with multiple arbitrary bait proteins by way of artificial-receptor constructs at sub-cellular feature size and applied this technology to simultaneously measure two-protein interaction kinetics inside an individual living cell.

Influences of Repeated Testing on Nonesterified Fatty Acid Taste

Findings that support the ability of humans to taste nonesterified fatty acids have been qualified by claims of substantial individual variability in sensitivity. We tested whether the number of testing visits impacted detection thresholds. Additionally, we explored the possibility that methodological differences in reported studies contributed to the high level of variance. Participants were randomized to either the modified staircase or ascending 3-alternative forced-choice methods, completed 10 test visits, and then switched to the alternate method. Repeated testing lowered the threshold concentration, and regardless of starting method, threshold concentrations were significantly lower with the second method. The staircase method generated data with less variation. The ascending method appears to be able to distinguish hypo and hypersensitive individuals as the variance at each visit increased over time, suggesting that the top performers continued to improve while the hyposensitive subjects maintained their low level of performance. The best individual threshold performance (lowest stimulus concentration) at each visit was obtained with the ascending method for 7 out of the first 10 visits (P = 0.117) and 17 out of the 20 visits (P = 0.001). Despite potential advantages of the ascending method in terms of sensitivity separation, there was no difference between the median of the first 10 visits, second 10 visits, and overall median obtained by the 2 testing methods. The most appropriate detection threshold testing method will depend on the goals of the researcher.

A review of the economic impact of high levels of variance in fertiliser spreading systems

Recent technological improvements in Geographical Information Systems (GIS) have made it possible to measure the accuracy of fertiliser spreading in the field. This demonstrates that the field coefficient of variation, "field CV", of actual spread patterns on farms is significantly higher than appreciated by most end users and service providers. Levels of field CV greater than 40% for spreading N fertiliser produces a 20% yield reduction, which in terms of urea on dairy pasture is potentially around $170 million nationally, and is economically significant. Manufacturers of fertiliser spreading equipment and ground-spread applicators have introduced improved delivery technologies which reduce field CV. Mostly these improvements relate to GPS use to assist drivers, automated maintenance of bout width, control of product flow and provision of automatic start-stop control. These improvements have the potential to reduce CV to 20% and reduce economic loss to 3%. Similarly, combinations of GIS methods and differential global positioning systems (DGPS) will assist pilots to reduce field CV from 70% to 40%. Keywords: Geographic Information Systems, coefficient of variation, fertiliser spreading accuracy, real time kinematic, spread pattern.

Determinants of biosecurity behaviour of British cattle and sheep farmers—A behavioural economics analysis

The paper analyses the impact of a priori determinants of biosecurity behaviour of farmers in Great Britain. We use a dataset collected through a stratified telephone survey of 900 cattle and sheep farmers in Great Britain (400 in England and a further 250 in Wales and Scotland respectively) which took place between 25 March 2010 and 18 June 2010. The survey was stratified by farm type, farm size and region.To test the influence of a priori determinants on biosecurity behaviour we used a behavioural economics method, structural equation modelling (SEM) with observed and latent variables. SEM is a statistical technique for testing and estimating causal relationships amongst variables, some of which may be latent using a combination of statistical data and qualitative causal assumptions.Thirteen latent variables were identified and extracted, expressing the behaviour and the underlying determining factors. The variables were: experience, economic factors, organic certification of farm, membership in a cattle/sheep health scheme, perceived usefulness of biosecurity information sources, knowledge about biosecurity measures, perceived importance of specific biosecurity strategies, perceived effect (on farm business in the past five years) of welfare/health regulation, perceived effect of severe outbreaks of animal diseases, attitudes towards livestock biosecurity, attitudes towards animal welfare, influence on decision to apply biosecurity measures and biosecurity behaviour.The SEM model applied on the Great Britain sample has an adequate fit according to the measures of absolute, incremental and parsimonious fit. The results suggest that farmers’ perceived importance of specific biosecurity strategies, organic certification of farm, knowledge about biosecurity measures, attitudes towards animal welfare, perceived usefulness of biosecurity information sources, perceived effect on business during the past five years of severe outbreaks of animal diseases, membership in a cattle/sheep health scheme, attitudes towards livestock biosecurity, influence on decision to apply biosecurity measures, experience and economic factors are significantly influencing behaviour (overall explaining 64% of the variance in behaviour).Three other models were run for the individual regions (England, Scotland and Wales). A smaller number of variables were included in each model to account for the smaller sample sizes. Results show lower but still high levels of variance explained for the individual models (about 40% for each country). The individual models’ results are consistent with those of the total sample model. The results might suggest that ways to achieve behavioural change could include ensuring increased access of farmers to biosecurity information and advice sources.

Investigating the cognitive precursors of emotional response to cancer stress: Re‐testing Lazarus's transactional model

Lazarus's Transactional Model of stress and coping underwent significant theoretical development through the 1990s to better incorporate emotional reactions to stress with their appraisal components. Few studies have robustly explored the full model. This study aimed to do so within the context of a major life event: cancer diagnosis. A repeated measures design was used whereby data were collected using self-report questionnaire at baseline (soon after diagnosis), and 3- and 6-month follow-up. A total of 160 recently diagnosed cancer patients were recruited (mean time since diagnosis = 46 days). Their mean age was 64.2 years. Data on appraisals, core-relational themes, and emotions were collected. Data were analysed using both Spearman's correlation tests and multivariate regression modelling. Longitudinal analysis demonstrated weak correlation between change scores of theoretically associated components and some emotions correlated more strongly with cognitions contradicting theoretical expectations. Cross-sectional multivariate testing of the ability of cognitions to explain variance in emotion was largely theory inconsistent. Although data support the generic structure of the Transactional Model, they question the model specifics. Larger scale research is needed encompassing a wider range of emotions and using more complex statistical testing. WHAT IS ALREADY KNOWN ON THIS SUBJECT?: • Stress processes are transactional and coping outcome is informed by both cognitive appraisal of the stressor and the individual's emotional response (Lazarus & Folkman, 1984). • Lazarus (1999) made specific hypotheses about which particular stress appraisals would determine which emotional response, but only a small number of these relationships have been robustly investigated. • Previous empirical testing of this theory has been limited by design and statistical limitations. WHAT DOES THIS STUDY ADD?: • This study empirically investigates the cognitive precedents of a much larger range of emotional outcomes than has previously been attempted in the literature. • Support for the model at a general level is established: this study demonstrates that both primary and secondary appraisals, and core-relational themes are important variables in explaining variance in emotional outcome. • The specific hypotheses proposed by Lazarus (1999) are not, however, supported: using data-driven approaches we demonstrate that equally high levels of variance can be explained using entirely different cognitive appraisals than those hypothesized.

Optimal resource allocation in a serotinous non‐resprouting plant species under different fire regimes

Summary Serotiny, the retention of mature seeds in closed fruits within the canopy for over a year, is a common trait in fire‐prone environments. When competition with adult plants prevents seedling establishment between fire events and in the absence of post‐release soil seed dormancy, strong serotiny, i.e. the retention of all seeds until the next fire, appears as the best strategy. Despite the low levels of inter‐fire seed recruitment for several species in both Australian and South African fire‐prone environments, considerable variation in the duration of fruit retention is nevertheless observed among species. Our aim is to predict optimal age‐specific reproductive schedules in a perennial, serotinous species, when cone maintenance is costly. We focus on species where adults are killed by fire, without a soil seed‐bank. We explicitly consider a trade‐off between growth (which determines plant survival), seed production and seed maintenance. In our model recruitment relies upon fire events. We use dynamic programming to determine, for given fire regimes, the optimal pattern of resource allocation. We further study the effect of changes in fire regime on the viability of populations adapted to some historical fire regime. We find that, whenever maximal plant survival probability is low, the optimal strategy consists in reducing resource allocation to seed maintenance while increasing resource allocation to annual seed production. This illustrates a trade‐off between current and future reproduction. A low rather than a strong level of serotiny should evolve whenever the variance of fire intervals is large and the mean fire interval is low. Low levels of serotiny could constitute a bet‐hedging strategy with decreasing predictability of the arrival of fire. Once adapted to some historical fire regime, serotinous populations are highly sensitive to a change in mean fire frequency and to an increase in the variance of fire intervals. Populations adapted to a historically high level of variance in fire return are more robust to changes in fire regime. Synthesis: Life‐history trade‐offs and low predictability of fire intervals may favour low rather than strong levels of serotiny even when recruitment essentially occurs just after fire events.

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Optimal response in the Lamb–Oseen vortex

The optimal response in the Lamb–Oseen vortex is studied by considering the harmonically forced problem with frequency ω. High variance levels are sustained in these systems under periodic forcing. In the axisymmetric case n=0, the response is the largest when the input frequency is zero. When considering helical perturbations n=1, large response is excited through resonance mechanism at moderate and large wavelengths. At smaller wavelengths, large response is excited by steady forcing. For perturbations with higher azimuthal wavenumbers |n|>1, the magnitudes of the response are smaller than those for helical modes. For given axial wavenumber and input frequency, the response increases rapidly with Re, which points to the significance of energy growth in high-Reynolds-number practical flows.