Andreas Tsatsaris

Abstract: The regional in time and in space multi-temporal land surface temperature (LST) MODIS dataset and elevation data are used in order to compute the day and night temperature variation in Greece in 2008. Clustering was applied and eight cluster centroids captured the temporal pattern of near-diurnal temperature (01:30 AM and 01:30 PM) variability while elevation statistics were computed per cluster. The spatial distribution of the clusters indicate that mean elevation, elevation variability, proximity to the sea, and the major inland water bodies were the key factors controlling the near diurnal LST variability in Greece.

Abstract: Monthly night averaged land surface temperature (LST) imagery is analyzed throughout a year-period (2008), in an attempt to capture the seasonal variability of LST, and parametrically represent and classify the African Countries. Segmentation outlined in an objective way the temporal variation of LST during the 2008, grouped in 9 zones with distinct spatial distribution, each one presenting a distinct annual variation of monthly LST. Tuberculosis incidence per county for the year 2008 was correlated to the percentage areal occurrence of the 9 biophysical zones. More specifically statistical analysis indicates that there is an increase of TB-IR per country if the percent occurrence of either zone 4 or zone 6 is increased. Such evidence was already known, but it is the first time that this correlation was quantified on the basis of high resolution LST data comparable to the previous studies that were based on the very sparse meteorological stations network. The MODIS multi-temporal LST data can assist the modeling of the disease risk and disease spatial distribution as well as environmental modeling, climatic change studies at moderate resolution/country level scale.

Abstract: The aim of the current research effort is to include biophysical multi-temporal data and more specifically land surface temperature (LST) in the terrain modeling process that traditionally was based only on digital elevation data processing. The terrain partition framework (spatial objects) is defined by the borderlines of prefecture authorities of Greece. Each object is represented by a set of attributes derived from the digital elevation data, and objects are organized into clusters on the basis of their terrain dependent representation. Finally, the terrain is segmented to regions on the basis of the multi-temporal LST data, each region presenting a different thermal signature. The thermal regions are used in the spatial objects parametric representation and a new index is devised (LST climatic index) expressing the biophysical suitability of spatial objects at moderate resolution scale.

Abstract: In Cyprus, leishmaniasis has been considered exclusively a veterinary problem. It was prevalent before 1945, and until its recent reemergence, it was nearly eradicated by 1996 as a consequence of the destruction of reservoir hosts and vectors. A survey carried out to provide an unbiased estimate of current transmission rates in dogs and humans showed a 9-fold increase in dog seroprevalence (reaching 14.9%) compared with 10 years ago. However, no human cases caused by Leishmania infantum were detected, although L. donovani cases were reported recently. The 62 strains isolated from dogs were typed as L. infantum MON-1 (98.4%), which is the predominating zymodeme in the Mediterranean region, and MON-98 (1.6%). The Phlebotomus species P. tobbi (vector of L. infantum in Cyprus), P. galilaeus, and P. papatasi were the predominant species captured. Two transmission cycles seem to run in parallel in Cyprus: in dogs with L. infantum and in humans with L. donovani.

Abstract: Abstract Rodents play an active role in the transmission of a number of zoonoses by harboring and disseminating the pathogens involved, either through their biological materials or via their ectoparasites. Hence, the spatial and seasonal distribution of potential agents of zoonoses may be studied by examining their distribution in the rodent vectors and their ectoparasites. A surveillance was conducted in wild rodents in 51 different areas of Cyprus, an island ecosystem, to monitor the reemergence of Echinococcus granulosus and Encephalomyocarditis virus (pathogens that have been eradicated from Cyprus), to study the presence and dispersal of Salmonella spp. (a bacterium found in patients and poultry in the island), as well as to investigate the presence of helminth parasites and rodent ectoparasites. Biological material collected from 625 rodents, examined macroscopically, microscopically, and after culture, showed that the most widespread pathogens encountered in wild rats (Rattus rattus and Rattus norvegicus) were helminth parasites, found in 92 animals (three helminth species found for the first time in Cyprus: Cysticercus fasciolaris, Hymenolepis diminuta, and Physalloptera spp.), and Salmonella spp., detected in the intestine of 56 rats (12 different Salmonella spp. and serotypes). None of the rodents were found infected with the cestode Echinococcus or Encephalomyocarditis virus, indicating that the control measures taken by the Veterinary Services on the island prevented its reestablishment despite changing conditions. The rodents were also free of the nematode Trichinella. Over 40% of the rats collected were infested with fleas, mainly Xenopsylla cheopis. The results, analyzed using the Geographical Information System technology, revealed two of the areas studied as high risk for public health.

Abstract:

Abstract: Accessing the infrastructure networks, the urban concentrations, the commercial and other activities or key locations, is considered by the spatial planners as a significant and sensitive variable for the territorial analysis. The spatial policies are determined today by the principals of equal and balanced distribution of human resources and activities, as well as by the systematic study of territorial disparities in the deepest territorial analysis detail level possible. The traditional calculative methods of accessibility indicators, does not take into account the entire space of the study area. In the contrary, it’s mainly based on calculating the travel cost on linear networks using the "arc-node" topologies. According to these methodologies, the variables (time, distance, or other types of cost) are calculated only for the network elements (nodes, lines). During the recent years, some published studies have appointed the above issue. Accessibility is faced as continuous data thus it is valued and attributed in the entire area of study and not just on the network body. This study’s main objective is to generate an accumulative travel cost indicator for the Greek territory, using all major transportation means. In addition the respective spatial typology will be created. The indicator is produced using three distinctive spatial levels representing the three transportation means (land, sea and air transportation). The study’s methodology is based on the formation of continuous cost surface model, in raster format, using all the aforementioned transportation nodes. The travel cost value that each cell on the surface will be assigned to, is the absolute time of traveling towards the transportation nodes or towards specific linear network elements. An emphasis is given to the study’s cartographic component as well as to the comprehensive use of spatial analysis techniques which are available on GIS software.

Abstract: The aim of this paper is to present some research hypotheses and empirical evidence concerning the geographical distribution and spread of leishmaniasis in Greece and particularly in the Greater Athens region, through spatial analysis in a GIS environment. Greece is the WHO Collaborating Center for research and training in Mediterranean zoonoses . Research for leishmaniasis in Greece has indicated that most of the incidents of the disease are concentrated in the Greater Athens region. The results presented in this paper are based on a research project which is currently carried out by the Technological Educational Institution of Athens in collaboration with the University of Crete and the Aristotle University of Thessalonica. The main hypothesis in this paper is that there is a geographical dimension in the diffusion of the disease of leishmaniasis in the Greater Athens region. This dimension includes several environmental factors as indicated in the relevant literature (i.e. elevation, vegetation, meteorological factors, the presence of quarries and dump sites and socioeconomic factors), but also the hypothesis that the incidents of the disease are clustered in the foothills of mountains which surround the Athens Basin, while they tend to follow the urban expansions towards these mountains. The available data concern incidents of leishmaniasis in the years 1961-2004. The incidents are mapped as well as the factors which are believed to affect the spatial distribution of the disease. The results are combined in a geographical database so that the possible interplay among them can be detected employing methods of spatial analysis. The preliminary results indicate that the above stated hypothesis is supported with some qualifications regarding mostly the elevation parameter.