Valantis Malesios - Academia.edu (original) (raw)

Papers by Valantis Malesios

Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurg... more Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurgence of malaria. Here, we develop a model-based framework that integrates ento-mological, geographical, social and environmental evidence in order to guide the mosquito control efforts and apply this framework to data from an entomological survey study conducted in Central Greece. Our results indicate that malaria transmission risk in Greece is potentially substantial. In addition, specific districts such as seaside, lakeside and rice field regions appear to represent potential malaria hotspots in Central Greece. We found that appropriate maps depicting the basic reproduction number, R 0 , are useful tools for informing policy makers on the risk of malaria resurgence and can serve as a guide to inform recommendations regarding control measures.

Journal of Cleaner Production, 2014

Corporate Social Responsibility and Environmental Management, 2013

The concept of corporate social responsibility (CSR) is closely intertwined with increased engage... more The concept of corporate social responsibility (CSR) is closely intertwined with increased engagement with stakeholders and integration of their concerns into core business processes. In this respect, stakeholders' viewpoint of CSR is deemed to be essential in shaping pertinent policies, plans and programs. However, current literature indicates an emphasis on the managerialist perspective whereas insights of non-business social constituents are considerably underrepresented. This is where this paper seeks to contribute by attempting to examine the non-governmental organizations' perceptions of socially responsible business conduct. Findings suggest that NGOs perceptions reflect two dominant views, a progressive viewpoint where socially responsible behavior offers win-win opportunities and a narrow perspective where wider responsibility is an unfruitful business practice. Nevertheless, different types of NGOs attributed similar importance on a number of socially responsible practices. Copyright

An increasing number of large corporations around the world engage in accounting for and reportin... more An increasing number of large corporations around the world engage in accounting for and reporting on their plans and measures towards climate change, as part of their environmental responsibility agenda. Using a disclosure index, this study investigates the status of the disclosure practices of the top 100 companies operating in Greece with respect to the pivotal issue of climate change. Determinants which drive Greek companies to publicly disclose such information are examined while overlapping perspectives for the Greek case are outlined. The analysis suggests that only a small group of leading Greek companies appears to endorse a climate change discourse as an instrument of empowering stakeholders' decision-making. Most other corporations still tend to disregard disclosure practices of their actions towards this global issue.

Management Decision, 2015

ABSTRACT Rangelands are used in many countries for water supply, cattle – breeding, outdoor recre... more ABSTRACT Rangelands are used in many countries for water supply, cattle – breeding, outdoor recreation and many other purposes related to improvement of life quality. The aim of this paper is the investigation of the attitudes of the local people in a remote rural area concerning the contribution of rangeland resources in the rural development. Our study was conducted with the use of a specially designed questionnaire and it took place in the area of Evros prefecture. The questionnaire included questions concerning items measuring various benefits and contributions in the quality of life by rangelands. The data were analyzed using descriptive statistics and the methodology of confirmatory factor analysis. Our results showed that the latent structure of overall benefits from rangelands is strongly related to three main factors of benefits, with most important being the recreational benefits factor, as viewed by the local people.

Epidemic data often possess certain characteristics, such as the presence of many zeros, the spat... more Epidemic data often possess certain characteristics, such as the presence of many zeros, the spatial nature of the disease spread mechanism , environmental noise, serial correlation and dependence on time varying factors. This paper addresses these issues via suitable Bayesian modelling. In doing so we utilise a general class of stochastic regression models appropriate for spatio-temporal count data with an excess number of zeros. The developed regression framework does incorporate serial correlation and time varying covariates through an Ornstein Uhlenbeck process formulation. In addition, we explore the effect of different priors, including default options and variations of mixtures of g-priors. The effect of different distance kernels for the epidemic model component is investigated. We proceed by developing branching process-based methods for testing scenarios for disease control, thus linking traditional epidemiological models with stochastic epidemic processes, useful in policy-focused decision making. The approach is illustrated with an application to a sheep pox dataset from the Evros region, Greece.

Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurg... more Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurgence of malaria. Here, we develop a model-based framework that integrates entomological, geographical, social and environmental evidence in order to guide the mosquito control efforts and apply this framework to data from an entomological survey study conducted in Central Greece. Our results indicate that malaria transmission risk in Greece is potentially substantial. In addition, specific districts such as seaside, lakeside and rice field regions appear to represent potential malaria hotspots in Central Greece. We found that appropriate maps depicting the basic reproduction number, 0 R , are useful tools for informing policy makers on the risk of malaria resurgence and can serve as a guide to inform recommendations regarding control measures.

Various mathematical models have been proposed in the recent literature for estimating the h-inde... more Various mathematical models have been proposed in the recent literature for estimating the h-index using measures such as number of articles (P) and citations received (C). These models have been previously empirically tested assuming a mathematical model and predetermining the models' parameter values at some fixed constant. The present study, from a statistical modeling viewpoint, investigates alternative distributions commonly used for this type of point data. The study shows that the typical assumptions for the parameters of the h-index mathematical models in such representations are not always realistic, with more suitable specifications being favorable. Prediction of the h-index is also demonstrated.

Braun, Glänzel, and Schubert (2006) recommended using the h-index as an alternative to the journa... more Braun, Glänzel, and Schubert (2006) recommended using the h-index as an alternative to the journal impact factor (IF) to qualify journals. In this paper, a Bayesian-based sensitivity analysis is performed with the aid of mathematical models to examine the behavior of the journal h-index to changes in the publication/citation counts of journals. Sensitivity of the h-index was most apparent for changes in the number of citations, revealing similar patterns of behavior for almost all models and independently to the field of research. In general, the h-index was found to be robust to changes in citations up to approximately the 25th percentile of the citation distribution, inflating its value afterwards.

SUMMARY We present and analyse data collected during a severe epidemic of foot-and-mouth disease ... more SUMMARY We present and analyse data collected during a severe epidemic of foot-and-mouth disease (FMD) that occurred between July and September 2000 in a region of northeastern Greece with strategic importance since it represents the southeastern border of Europe and Asia. We implement generic Bayesian methodology, which offers flexibility in the ability to fit several realistically complex models that simultaneously capture the presence of 'excess' zeros, the spatio-temporal dependence of the cases, assesses the impact of environmental noise and controls for multicollinearity issues. Our findings suggest that the epidemic was mostly driven by the size and the animal type of each farm as well as the distance between farms while environmental and other endemic factors were not important during this outbreak. Analyses of this kind may prove useful to informing decisions related to optimal control measures for potential future FMD outbreaks as well as other acute epidemics such as FMD.

Epidemic data often possess certain characteristics, such as the presence of many zeros, the spat... more Epidemic data often possess certain characteristics, such as the presence of many zeros, the spatial nature of the disease spread mechanism, environmental noise, serial correlation and dependence on time-varying factors. This paper addresses these issues via suitable Bayesian modelling. In doing so, we utilize a general class of stochastic regression models appropriate for spatio-temporal count data with an excess number of zeros. The developed regression framework does incorporate serial correlation and time-varying covariates through an Ornstein– Uhlenbeck process formulation. In addition, we explore the effect of different priors, including default options and variations of mixtures of g-priors. The effect of different distance kernels for the epidemic model component is investigated. We proceed by developing branching process-based methods for testing scenarios for disease control , thus linking traditional epidemiological models with stochastic epidemic processes, useful in policy-focused decision making. The approach is illustrated with an application to a sheep pox dataset from the Evros region, Greece.

This paper aims to assess the relative importance of a NIMBY (‘Not-In-My-Back-Yard’) stance on an... more This paper aims to assess the relative importance of a NIMBY (‘Not-In-My-Back-Yard’) stance on an individual’s opposition to the siting of a wind farm vis-a-vis other predictors, such as perceived effects (costs, risks and benefits associated with the
project), perceived fairness of the siting decision and societal trust. Data originate from two case studies, a small wind farm of just two wind turbines in southern Greece and a mega-project of 153 turbines on the Greek island of Lesvos (aggregate N =
334). We use structural equation modelling (SEM) for testing the theoreticallysuggested relations between the various constructs. We find that NIMBY is not the most important predictor of opposition while it is strongly correlated with other predictors, such as the perceived unfairness of the siting decision as well as the risks and costs associated with the wind farm. These latter findings undermine the commonsense idea that wishing a wind farm out of one’s vicinity (‘Not-In-My-Back-Yard’) is an example of mere ‘free-riding’. Since the fit of the SEM models was found to be
moderate, we discuss the limitations of our study and the implications of our findings as well as suggesting pathways for future research.

In this paper, we attempt to examine and compare the performance of two GPS receivers of differen... more In this paper, we attempt to examine and compare the performance of two GPS receivers of different orientation, one recreational and another more precise, in forested areas. In doing this, we conducted a field test on horizontal and vertical positional errors of GPS positioning at different points in the forested area of Taxiarchis – Vrastama University forest. The two Global Positioning System receivers were used to determine the positional accuracy of a selected number of points under tree canopies. Specifically, the precision and accuracy of Garmin's GPS positioning at different points were calculated and compared with the corresponding positioning and accuracy of another GPS system, namely the TOPCON GPS. By the calculation of various measures of accuracy and precision suitable for GPS receivers and the use of statistical methods, we have shown that accuracy between the different receivers differed significantly. Also, regression analysis revealed that the basal area and the number of available satellites are the most important factors for predicting position error.

Braun et al. (2006) recommended using the h-index as an alternative to the journal impact factor ... more Braun et al. (2006) recommended using the h-index as an alternative to the journal impact factor (IF) to qualify journals. In this paper, a Bayesian-based sensitivity analysis is performed with the aid of mathematical models to examine the behavior of the journal h-index to changes in the publication/citation counts of journals. Sensitivity of the h-index was most apparent for changes in the number of citations, revealing similar patterns of behavior for almost all models and independently to the field of research. In general, the h-index was found to be robust to changes in citations up to approximately the 25 th percentile of the citation distribution, inflating its value afterwards.

An important disadvantage of the h-index is that typically it cannot take into account the specif... more An important disadvantage of the h-index is that typically it cannot take into account the specific field of research of a researcher. Usually sample point estimates of the average and median h-index values for the various fields are reported that are highly variable and dependent of the specific samples and it would be useful to provide confidence intervals of prediction accuracy. In this paper we apply the non-parametric bootstrap technique for constructing confidence intervals for the h-index for different fields of research. In this way no specific assumptions about the distribution of the empirical h-index are required as well as no large samples since that the methodology is based on resampling from the initial sample. The results of the analysis showed important differences between the various fields. The performance of the bootstrap intervals for the mean and median h-index for most fields seems to be rather satisfactory as revealed by the performed simulation.

Journal of Cleaner Production, 2014

Corporate Social Responsibility and Environmental Management, 2013

Management Decision, 2015

Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurg... more Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurgence of malaria. Here, we develop a model-based framework that integrates entomological, geographical, social and environmental evidence in order to guide the mosquito control efforts and apply this framework to data from an entomological survey study conducted in Central Greece. Our results indicate that malaria transmission risk in Greece is potentially substantial. In addition, specific districts such as seaside, lakeside and rice field regions appear to represent potential malaria hotspots in Central Greece. We found that appropriate maps depicting the basic reproduction number, 0 R , are useful tools for informing policy makers on the risk of malaria resurgence and can serve as a guide to inform recommendations regarding control measures.

Epidemic data often possess certain characteristics, such as the presence of many zeros, the spat... more Epidemic data often possess certain characteristics, such as the presence of many zeros, the spatial nature of the disease spread mechanism, environmental noise, serial correlation and dependence on time-varying factors. This paper addresses these issues via suitable Bayesian modelling. In doing so, we utilize a general class of stochastic regression models appropriate for spatio-temporal count data with an excess number of zeros. The developed regression framework does incorporate serial correlation and time-varying covariates through an Ornstein– Uhlenbeck process formulation. In addition, we explore the effect of different priors, including default options and variations of mixtures of g-priors. The effect of different distance kernels for the epidemic model component is investigated. We proceed by developing branching process-based methods for testing scenarios for disease control , thus linking traditional epidemiological models with stochastic epidemic processes, useful in policy-focused decision making. The approach is illustrated with an application to a sheep pox dataset from the Evros region, Greece.

Epidemic data often posses certain characteristics, such as the presence of many zeros, the spati... more Epidemic data often posses certain characteristics, such as the presence of many zeros, the spatial nature of the disease spread mechanism or environmental noise. This paper addresses these issues via suitable Bayesian modelling. In doing so we utilise stochastic regression models appropriate for spatio-temporal count data with an excess number of zeros. In addition we explore the eﬀect of diﬀerent priors, including default options and techniques based upon variations of mixtures of g-priors. The eﬀect of diﬀerent distance kernels for the epidemic model component is extensively explored. We proceed by developing branching process-based methods for testing scenarios for disease control, thus linking traditional spatio-temporal models with epidemic processes, useful in policy-focused decision making. The approach is illustrated with an application to a historical sheep pox dataset from the Evros region, Greece.