Showing papers by "University of the Aegean published in 2010"

Combined Measurement and QCD Analysis of the Inclusive e± p Scattering Cross Sections at HERA

Abstract: A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.

General stabilizing effects of plant diversity on grassland productivity through population asynchrony and overyielding

Abstract: Insurance effects of biodiversity can stabilize the functioning of multispecies ecosystems against environmental variability when differential species' responses lead to asynchronous population dynamics. When responses are not perfectly positively correlated, declines in some populations are compensated by increases in others, smoothing variability in ecosystem productivity. This variance reduction effect of biodiversity is analogous to the risk-spreading benefits of diverse investment portfolios in financial markets. We use data from the BIODEPTH network of grassland biodiversity experiments to perform a general test for stabilizing effects of plant diversity on the temporal variability of individual species, functional groups, and aggregate communities. We tested three potential mechanisms: reduction of temporal variability through population asynchrony; enhancement of long-term average performance through positive selection effects; and increases in the temporal mean due to overyielding. Our results support a stabilizing effect of diversity on the temporal variability of grassland aboveground annual net primary production through two mechanisms. Two-species communities with greater population asynchrony were more stable in their average production over time due to compensatory fluctuations. Overyielding also stabilized productivity by increasing levels of average biomass production relative to temporal variability. However, there was no evidence for a performance-enhancing effect on the temporal mean through positive selection effects. In combination with previous work, our results suggest that stabilizing effects of diversity on community productivity through population asynchrony and overyielding appear to be general in grassland ecosystems.

Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination

Abstract: Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant-pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.

Mobile healthcare information management utilizing Cloud Computing and Android OS

Abstract: Cloud Computing provides functionality for managing information data in a distributed, ubiquitous and pervasive manner supporting several platforms, systems and applications. This work presents the implementation of a mobile system that enables electronic healthcare data storage, update and retrieval using Cloud Computing. The mobile application is developed using Google's Android operating system and provides management of patient health records and medical images (supporting DICOM format and JPEG2000 coding). The developed system has been evaluated using the Amazon's S3 cloud service. This article summarizes the implementation details and presents initial results of the system in practice.

Global Economic Crisis and Tourism: Consequences and Perspectives

Abstract: The International Academy for the Study of Tourism convened a session on global economic crisis and tourism during its 20th anniversary conference in Mallorca, Spain, in June 2009. Three articles featuring on the impacts of economic downturn on tourism in Asia and the Pacific, Europe, and North America have resulted and appeared in this issue of the Journal of Travel Research. This summary aims at an integrated discussion on the consequences and perspectives on the global economic crisis and tourism. The prospects of world tourism for the years to come are also reflected.

Effects of patch size and density on flower visitation and seed set of wild plants: a pan-European approach

Abstract: Summary 1. Habitat fragmentation can affect pollinator and plant population structure in terms of species composition, abundance, area covered and density of flowering plants. This, in turn, may affect pollinator visitation frequency, pollen deposition, seed set and plant fitness. 2. A reduction in the quantity of flower visits can be coupled with a reduction in the quality of pollination service and hence the plants’ overall reproductive success and long-term survival. Understanding the relationship between plant population size and ⁄ or isolation and pollination limitation is of fundamental importance for plant conservation. 3. We examined flower visitation and seed set of 10 different plant species from five European countries to investigate the general effects of plant populations size and density, both within (patch level) and between populations (population level), on seed set and pollination limitation. 4. We found evidence that the effects of area and density of flowering plant assemblages were generally more pronounced at the patch level than at the population level. We also found that patch and population level together influenced flower visitation and seed set, and the latter increased with increasing patch area and density, but this effect was only apparent in small populations. 5. Synthesis. By using an extensive pan-European data set on flower visitation and seed set we have identified a general pattern in the interplay between the attractiveness of flowering plant patches for pollinators and density dependence of flower visitation, and also a strong plant species-specific response to habitat fragmentation effects. This can guide efforts to conserve plant–pollinator interactions, ecosystem functioning and plant fitness in fragmented habitats.

Vehicle Logo Recognition Using a SIFT-Based Enhanced Matching Scheme

Abstract: In this paper, a new algorithm for vehicle logo recognition on the basis of an enhanced scale-invariant feature transform (SIFT)-based feature-matching scheme is proposed. This algorithm is assessed on a set of 1200 logo images that belong to ten distinctive vehicle manufacturers. A series of experiments are conducted, splitting the 1200 images to a training set and a testing set, respectively. It is shown that the enhanced matching approach proposed in this paper boosts the recognition accuracy compared with the standard SIFT-based feature-matching method. The reported results indicate a high recognition rate in vehicle logos and a fast processing time, making it suitable for real-time applications.

Cardioprotective effect of metoprolol and enalapril in doxorubicin‐treated lymphoma patients: A prospective, parallel‐group, randomized, controlled study with 36‐month follow‐up

Abstract: Anthracyclines have contributed to a marked increase in survival in different types of cancer [1,2]. Unfortunately, they are associated with dose-dependent cardiotoxicity and heart failure (HF) [3–8]. Change to a weekly dosage schedule with slow infusions has been tested, a strategy that requires more frequent hospital visits and increased storage resources[7,9]. Liposomal anthracycline formulations with reduced drug exposure and lower plasma concentrations may still be cardiotoxic at higher cumulative doses [10]. Beta-blockers and angiotensin converting enzyme(ACE) inhibitors have been shown to reduce anthracycline-induced cardiotoxicity,but have not been tested in long-term prospective, randomized,controlled studies with well defined cardiotoxicity criteria and careful cardiac function monitoring [11–16]. We investigated doxorubicin-induced clinical or subclinical cardiotoxicity in lymphoma patients after concomitant prophylactic therapy with metoprolol or enalapril or no concomitant treatment. We examined whether cardiotoxicity was related to the treatment or any other variable. We found that HF was less frequent under concomitant treatment than no treatment, especially in the metoprolol group, but the differences were not significant. No association was found between the presence of cardiotoxicity and concomitant treatment or other variable apart of age that had a significant impact. The marginal benefit seen with metoprolol should be investigated further.

Ecosystem services and biodiversity conservation: concepts and a glossary

Abstract: The RUBICODE project draws on expertise from a range of disciplines to develop and integrate frameworks for assessing the impacts of environmental change on ecosystem service provision, and for rationalising biodiversity conservation in that light. With such diverse expertise and concepts involved, interested parties will not be familiar with all the key terminology. This paper defines the terms as used within the project and, where useful, discusses some reasoning behind the definitions. Terms are grouped by concept rather than being listed alphabetically.

Port Governance Reforms in Diversified Institutional Frameworks: Generic Solutions, Implementation Asymmetries:

Abstract: Bringing in neo-institutional perspectives, this paper investigates the recent corporatisation process of three seaports in Asia and Europe. We focus on whether the newly established seaport governance structures follow a path largely affected by the local/national institutional frameworks and the political traditions in place. Findings confirm that path-dependent decisions largely preserve the institutional characteristics of local/national systems, resulting in implementation asymmetries when different countries seek generic governance solutions.

The nature of millennial-scale climate variability during the past two glacial periods.

Abstract: Periodic iceberg discharges during the last glacial period led to a slowdown of the Atlantic meridional overturning circulation Sediment records from the Portuguese margin show that similar events punctuated the penultimate glacial period as well, although their duration and broader climatic impacts were modified by different background climate conditions During the last glacial period, iceberg discharges into the North Atlantic disrupted the meridional overturning circulation, leading to cooling in the Northern Hemisphere and warming in Antarctica1,2 This asymmetric response can be explained by a bipolar see-saw mechanism3,4,5, whereby changes in the strength of the meridional overturning circulation lead to changes in the interhemispheric heat transport It is unclear, however, to what extent the response of the overturning circulation is a function of freshwater flux and boundary climate conditions4 Here we use foraminiferal isotope and pollen records from the Portuguese margin to reconstruct surface- and deep-water hydrography and atmospheric changes during the last and penultimate glacial periods When we compare our records with temperature reconstructions from Antarctica6, we find that the bipolar see-saw was a characteristic feature of both glacial periods However, the comparison also underlines the dependence of the bipolar see-saw on background climate and magnitude of iceberg discharge It also suggests that an intensified hydrological cycle may lead to a weaker overturning circulation with a smaller disruption threshold and extended North Atlantic stadial durations

Assessing risk of and adaptation to sea-level rise in the European Union: An application of DIVA

Abstract: This paper applies the DIVA model to assess the risk of and adaptation to sea-level rise for the European Union in the 21st century under the A2 and B1 scenarios of the Intergovernmental Panel on Climate Change. For each scenario, impacts are estimated without and with adaptation in the form of increasing dike heights and nourishing beaches. Before 2050, the level of impacts is primarily determined by socio-economic development. In 2100 and assuming no adaptation, 780 × 103 people/year are estimated to be affected by coastal flooding under A2 and 200 × 103 people/year under B1. The total monetary damage caused by flooding, salinity intrusion, land erosion and migration is projected to be about US$ 17 × 109 under both scenarios in 2100; damage costs relative to GDP are highest for the Netherlands (0.3% of GDP under A2). Adaptation reduces the number of people flooded by factors of 110 to 288 and total damage costs by factors of 7 to 9. In 2100 adaptation costs are projected to be US$ 3.5 × 109 under A2 and 2.6 × 109 under B1; adaptation costs relative to GDP are highest for Estonia (0.16% under A2) and Ireland (0.05% under A2). These results suggest that adaptation measures to sea-level rise are beneficial and affordable, and will be widely applied throughout the European Union.

Strong convergence theorem by a hybrid extragradient-like approximation method for variational inequalities and fixed point problems

Abstract: The purpose of this paper is to investigate the problem of finding a common element of the set of fixed points F(S) of a nonexpansive mapping S and the set of solutions ? A of the variational inequality for a monotone, Lipschitz continuous mapping A. We introduce a hybrid extragradient-like approximation method which is based on the well-known extragradient method and a hybrid (or outer approximation) method. The method produces three sequences which are shown to converge strongly to the same common element of $${F(S)\cap\Omega_{A}}$$ . As applications, the method provides an algorithm for finding the common fixed point of a nonexpansive mapping and a pseudocontractive mapping, or a common zero of a monotone Lipschitz continuous mapping and a maximal monotone mapping.

Social factors influencing perceptions and willingness to pay for a market-based policy aiming on solid waste management

Abstract: Several instruments have been proposed for household solid waste management. In order for these instruments to be successful, it is essential to investigate social factors affecting the public's behaviour during their implementation. The present article aims to explore the influence of social parameters, connected with the concept of social capital, on the perceptions of the public in relation to a market-based instrument. In particular, the results of a case study, conducted on a Greek island community, are presented, regarding the perceptions and willingness to pay of individuals for an economic instrument, aimed at the minimization of waste volume and an increase in recycling. Furthermore, these issues are further explained taking into consideration the influence of four social capital parameters: social trust, institutional trust, social networks and compliance with social norms. In the conclusions of the study, it is underlined that, although citizens are negative towards the proposed policy, enforcement of social factors may significantly affect individuals’ perceptions and environmental behaviour during the final implementation of the policy tool.

New approaches in transportation planning: happiness and transport economics

Abstract: The measurement of social and psychological phenomena has been advanced by recent progress in the fields of behavioural economics and hedonic psychology. In addition, the increased interest in understanding how individuals perceive their own quality of life, has led to investigating the relations between various macro and individual level variables, generically subsumed as happiness. For many "happiness is considered to be an ultimate goal in life" and it plays an important role in the way people perceive the overall society they live in. Therefore, social scientists and behavioural economists are now stressing the importance of well-being measures, related to people's evaluations of their quality of life in addition to economic indicators. In the transport sector, project evaluation is mainly based on cost---benefit analyses using economic indicators. However, any provided transportation project/service impacts the quality of the travel experience, the well-being of travellers and their travel behaviour. Competitiveness of modes may be also affected by the promotion of derived or experienced travellers' well-being. Thus, existing behavioural travel choice models should be enhanced with regards to their behavioural validity incorporating the impacts of travelling happiness/ satisfaction. This study aims to understand and model the impact of stated (anticipated) happiness in the decision choice between a private transport mode--car, and a public transport mode--metro.

Implementing the Strategy

Abstract: Although confident that the international climate was receptive and the time ripe for a more forthcoming policy vis-a-vis Turkey, Greek decision makers271 had to test the new strategy against the interests of certain European Union (EU) countries. In other words, the lifting of Greece’s veto and the granting of candidate status to Turkey should be followed by a series of conditions to which Greece’s EU partners should concede. To this end, an unofficial Task Force was established at the Ministry of Foreign Affairs with the aim of sounding out EU partners’ response to an eventual U-turn in Greece’s policy vis-a-vis Turkey,272 while a series of diplomatic initiatives (official and unofficial contacts and discussions) were undertaken beginning in September 1999 by some of the key figures of Greece’s new strategy apparatus.273 Some of those meetings between Greek decision-makers and key political figures of certain EU partners succeeded in putting forward Greece’s new argumentation in a convincing way and, most importantly, in outlining the conditions that should be fulfilled in order for the Greek government to concede to the granting of a candidacy status to Turkey.