City Of Thessaloniki Research Articles

Analysis of the heat- and cold-related cardiovascular mortality in an urban mediterranean environment through various thermal indices

During the last decades the effects of thermal stress on public health have been a great concern worldwide. Thermal stress is determined by air temperature in combination with other meteorological parameters, such as relative humidity and wind speed. The present study is focused on the Mediterranean city of Thessaloniki, Greece and it aims to explore the association between thermal stress and mortality from cardiovascular diseases, using both air temperature and other thermal indices as indicators. For that, an over-dispersed Poisson regression function was used, in combination with distributed lag non-linear models, in order to capture the delayed and nonlinear effects of temperature. Our results revealed a reverse J-shaped exposure-response curve for the total population and females and a U-shaped association for males. In all cases examined, the minimum mortality temperature was identified around the 80th percentile of each distribution. It is noteworthy that despite the fact that the highest risks of cardiovascular mortality were estimated for exposure to extreme temperatures, moderate temperatures were found to cause the highest burden of mortality. On the whole, our estimations demonstrated that the population in Thessaloniki is more susceptible to cold effects and in regard with gender, females seem to be more vulnerable to ambient thermal conditions.

Small-Scale Analysis of Characteristics of the Wildland–Urban Interface Area of Thessaloniki, Northern Greece

In the past few years, the continuous expansion of urban development has created mixed forested, agricultural, and urban areas. These areas are called the wildland–urban interface (WUI), and they are characterized by increased human activities and land-use conversion, and they usually contribute to a high risk of wildfire occurrence. In the case of the peri-urban areas of Thessaloniki city, an effort was made to map, classify, and describe this wildland–urban interface, using Sentinel-2 satellite images of the area and very large scale orthophotos (VLSO) for the human settlements. Object-based image analysis (OBIA) was applied to classify landcover, combined with analysis of field data. The results showed that the WUI area in the city of Thessaloniki appears to the north and east of the city and covers an area of 2203.98 ha. The main characteristics affected by the ecological conditions of this area are the building (or human infrastructure) density, type, and the structure of forest vegetation. Human population pressure was found to be greatly differentiated between WUI areas belonging to different municipalities, the most affected was the municipality of Thessaloniki. A set of fire prevention silvicultural treatments are suggested for mitigating the fire danger in the area, accompanied by appropriate human awareness actions and the involvement of the local society. These measures include the reduction in crown bulk density and increase in crown base height through pruning (at least to 1/3 of total tree height), and low thinning, aiming to ensure that tree crowns of mature Pinus brutia trees are not in contact with one another. Both in the young P. brutia forest and the evergreen vegetation areas, thinning, pruning, and vegetation clearing is recommended adjusted according to each ecosystem.

Pre/Post-Fire Soil Erosion and Evaluation of Check-Dams Effectiveness in Mediterranean Suburban Catchments Based on Field Measurements and Modeling

The present study was conducted in the suburban forest of Thessaloniki city (Seich Sou), which constitutes one of the most significant suburban forests in Greece. In 1997, more than the half of the forest area was destroyed by a wildfire, after which soil erosion and flood control works (check-dams) were constructed in the burned areas. The aim of the study is to estimate the annual soil erosion rate for the last 30 years (pre- and post-fire periods) applying the WaTEM/SEDEM model, in order to investigate the impact of this wildfire on soil erosion, the effectiveness of the flood- and erosion-control works and the level of forest regeneration. It is the first time that WaTEM/SEDEM was calibrated and validated in Greece, taking into account soil erosion records from the 18 check-dams that were constructed in the study area in 2001. The mean annual erosion rate was 0.0419 t/ha/year, 0.998 t/ha/year and 0.08 t/ha/year for the pre-fire period, the first 3 years and 20 years after the fire, respectively. The results showed a very low erosion rate for the pre-fire period, an expected significant increase 3 years after the wildfire and a gradual decrease in the subsequent years until 2021. However, it seems that the post-fire regeneration of the forest has not been fully achieved, since the annual soil erosion rate at the long-term post-fire period is double compared with the pre-fire period. Concerning the check-dams’ effectiveness, it was observed that after 20 years of operation, they were non-silted, and most of them retained a small amount of sediments. This fact could be attributed to multiple factors such as the very thin soil depth, fire severity and catchment geomorphology, though the main reason seems to be the time elapsed between fire occurrence and the check-dams’ construction. The results of this study advance/strengthen the knowledge concerning the pre/post-fire soil erosion processes in already degraded ecosystems, while the calibrated model could serve as a useful tool able to be applied in other Mediterranean catchments of similar characteristics.

The way out of a crisis? the role of cities in Europeanization: a study of Thessaloniki city diplomacy

ABSTRACT Even though many stakeholders generally acknowledge cities’ presence and growing importance in international relations, the impact of their autonomous foreign policy remains unclear. Despite prior observations of city diplomacy, knowledge of how intensively city diplomacy is interconnected with the foreign policy of central governments is vague. The article is therefore focused on the circumstances that push cities to undertake diplomatic action and the consequent implications for the Europeanization process of the region. The conclusions reveal that Thessaloniki city diplomacy leverages the Europeanization of the region and has the capacity to complement the Greek government’s foreign policy. The article also argues that the cross-border exposure of cities implies possibilities for further Europeanization of the region.

A Communist Center in Thessaloniki at the Junction of Mediterranean and Post-Ottoman Spaces

This paper investigates a communist plan in the 1920s to establish a Middle Eastern center in the port city of Thessaloniki. To explain this counterintuitive choice, the paper situates Thessaloniki within two radical spaces. First, it shows the importance of post-Ottoman radical networks in making Thessaloniki a critical point of liaison in the 1920s. Second, it discusses the radical connections across the Mediterranean and the agency of revolutionary sailors in establishing these linkages.

Measuring Distance Learning System Adoption in a Greek University during the Pandemic Using the UTAUT Model, Trust in Government, Perceived University Efficiency and Coronavirus Fear

The COVID-19 pandemic has led most universities around the world using e-learning services as an alternative to their curricula. These distance learning tools can help universities expand and enhance their curricula with flexible learning techniques. In order to measure distance learning systems adoption in the University of Macedonia, a Greek university in the city of Thessaloniki, an extended version of the UTAUT model is introduced by using the constructs of Trust in Government regarding the management of the pandemic, Perceived University Efficiency on issues regarding distance learning provision and Corona Fear. To analyze the proposed model, an online survey of 471 university students was conducted. Data were analyzed using Partial Least Squares. The findings revealed that students’ attitudes toward University Efficiency affect key variables of the proposed model, such as Performance Expectancy, Effort Expectancy, Social Influence, Facilitation Conditions and Use Behavior. Additionally, Trust in Government affects Perceived University Efficiency, and Use Behavior and Corona Fear affects University Efficiency and Trust in the Government in the management of pandemic issues. In contradiction with other research, Corona Fear has no moderating effects. University efficiency, Trust in Government and Corona Fear, because of the effects that they have on key variables, may have important managerial implications when considering the adoption of distance learning systems during the pandemic and in general.

The Anticipated Use of Public Transport in the Post-Pandemic Era: Insights from an Academic Community in Thessaloniki, Greece

This paper investigates how the travel behavior relating to Public Transport (PT) changed during the COVID-19 pandemic, and which are the expectations about the extent of PT use post-pandemic. A revealed preferences questionnaire survey was distributed within an academic community in the city of Thessaloniki, Greece. To understand the factors potentially determining the future PT use, hierarchical ordered probit and bivariate ordered probit models were estimated. Results showed that the frequent PT users reduced by almost 75% during the pandemic. More than 29% of the local academic community members are reluctant to resume PT use at pre-pandemic levels. Non-captive users, teleworkers and those being unsatisfied with cleanliness and safety are less willing to travelling by PT post-pandemic. Female and under-stress passengers were found to particularly appreciate the use of facemasks and the increased service frequencies as post-pandemic policy measures. The study findings can inform the recovery strategies of transport authorities in order to retain the PT ridership at levels that will not threat the long-term viability of service provision. Future research may complement these findings by examining other population segments, such as the commuters and the elderly, under more advanced modelling techniques to account for additional unobserved behavioral patterns.

Innovation in the tourism industry through personalization for the case of Thessaloniki: Tourist types and their role in development strategies

The tourism industry has been one of the most significant and fastest-growing globally. The pandemic of COVID-19 had a crucial and unprecedented impact on tourism, from which it is currently trying to recover. Innovations and technology are among the most vital tools for this recovery. In order to effectively utilize and employ technological innovations, they need to be targeted toward the trends and desires of consumer demands, which are increasingly pointing to personalized experiences and products. Personalisation can significantly benefit businesses and improve consumer satisfaction, especially in tourism. To this end, the present paper explores tourist types through qualitative and quantitative analyses and formulates ten “personas” based on their unique technological, social, economic, and cultural traits and behaviour. Overall, tourists are open to the locality, willing to participate in events, taste local cuisine and interact with the local population. They consider security and quality as essential preconditions of visiting a destination. Cultural tourism appears as the most favoured scope of travelling. The individual types of tourists presented can play an essential role in implementing strategic planning and are necessary for creating personalized tourism products and experiences. The analysis focuses on the city of Thessaloniki (the second-largest city in Greece). The results are further utilized for creating personalized city tours through a newly developed innovative mobile application.

Evaluation of the 3D Near-Surface Velocity Structure in an Urban Environment from Ambient Noise Array Tomography: The Case of the City of Thessaloniki (Northern Greece)

Abstract We examine the implementation of ambient noise array tomography in an urban environment to assess the 3D near-surface shear wave velocity (VS) structure at an intermediate spatial scale (∼1 km2, depth range 200–300 m). The application employs cross correlation traces of vertical component ambient noise recordings from a local network installed in Thessaloniki city (Northern Greece), allowing the determination of Rayleigh wave travel times for the frequency range of 1.5–14 Hz. The results confirm the presence of a complex subsurface with strong lateral variations in the geology, with travel times varying up to almost one order of magnitude. A surface wave travel time tomography approach was applied for each frequency to determine the spatial variability of the group velocity, involving the use of approximate Fresnel volumes, as well as damping and spatial smoothing constraints to stabilize the results. We also employed an interfrequency smoothing scheme to obtain smooth but data-compatible dispersion curves at the cost of inverting all travel time data simultaneously. Following the application of several quality cutoff criteria, we reconstructed local group slowness dispersion curves for a predefined tomographic grid in the study area. The final 3D velocity model was determined by a modified Monte Carlo inversion of these dispersion curves and the spatial integration of the obtained 1D VS profiles. Different model parameterizations were tested for the inversion to determine the optimal datafit. The final 3D velocity model is in a very good agreement with the local geology, previous larger scale studies, and other geophysical surveys, providing additional structural constraints (such as hidden fault identification) for the complex sedimentary deposits and bedrock formation in Thessaloniki, up to the depth of ∼250–300 m. The introduction of the aforementioned modifications to the ambient noise array tomography suggests that it can be efficiently adjusted and employed as a reliable tool for imaging the 3D seismic structure in urban environments with complex geology.

HRMS screening of organophosphate flame retardants and poly-/perfluorinated substances in dust from cars and trucks: Occurrence and human exposure implications

Time spent within vehicles' cabin has been largely increased during the last years. As a result, the assessment of indoor dust quality is meaningful since dust can be a source of numerous emerging contaminants associated with adverse effects in human health. To this end, fourteen cars and ten trucks from the city of Thessaloniki, Northern Greece were selected to assess the quality of vehicles' microenvironments. An HRMS-based strategy was deployed for the target and non-target analysis of the collected samples. The target approach aimed at the accurate mass screening of nine organophosphate flame retardants (OPFRs) and nine per-/polyfluorinated compounds (PFAS), revealing mean concentrations for the OPFRs varied from <MQL–3409 ng/g for tris(1,3-dichloro-2-propyl) phosphate (TDCP), while the PFASs were either not detected (<MDL) or detected below the quantification limit (<MQL). To exploit the advanced technology of HRMS, a non-target analysis (NTA) workflow was also designed and employed, allowing the identification of 17 non-targets (plasticizers, PPCPs, pesticides and industrial chemicals) at identification confidence levels from 3 to 1. The statistical analysis between the positive findings and vehicles' conditions evidenced a possible of association just for individual cases. Lastly, a preliminary evaluation of human exposure to the target analytes was applied with the view to assess the potential harmful effects. All values were < 1 indicating no special effects because of exposure to this concentration level.

A sociolinguistic approach to the concept of translation ‘error’ in non-professional translation settings

Abstract This paper proposes a sociolinguistic approach to understanding the phenomenon of divergence from the standard norms of English that can be observed in public texts in the Greek city of Thessaloniki’s translation landscape. This approach fits in with the growing body of research that recognises that not all translations are carried out by professional translators. Certainly in the case of Thessaloniki, translations are typically carried out by non-professionals who draw on the linguistic experience and resources they possess in order to communicate with visitors and residents who do not understand Greek. As a result, several linguistic and pragmatic divergences from Standard English can be observed in the target text, which native speakers of English seem to be willing to disregard, provided that the message is intelligible. The sociolinguistic approach adopted in this paper reveals the translators’ effective use of the English language in conveying the message of the Greek source text, on the basis of the judgements expressed by translation professionals as well as native speakers of Greek and English.

Hospital Agios Dimitrios: The General Public Hospital of Thessaloniki.

The purpose of this article is to highlight the history of Hospital Agios Dimitrios, the General Hospital of Thessaloniki. During the early 20th century, many refugees settled in the Greek city of Thessaloniki. To address the growing public health needs of the city’s inhabitants, the Greek government established a health agency to offer medical care and respond to infectious disease outbreaks and epidemics. This initiative resulted in the construction or renovation of various hospitals. The Hospital Agios Dimitrios in Thessaloniki was completed in 1903. Its innovative architecture includes kiosks and wards designed to provide better ventilation and prevent the transmission of infectious diseases.

Micro-Mobility User Pattern Analysis and Station Location in Thessaloniki

In recent years, European countries have been trying to cultivate electrical scooters (e-scooters) as an alternative form of micro-mobility. The purchase and maintenance costs of private e-scooters are expensive so cities have been collaborating with companies to construct an e-scooter rental network. This paper aims to interpret the usage patterns of e-scooters and suggest optimal station locations for charging and parking. The dataset depicts a three-month time period (August, September, and May of the year 2020/2021) of 26,374 trips, in which there were no pandemic limitations. The results are based on two main features: the initial–final position of the e-scooter (the total distance is unknown) and the travel time. Most e-scooter rides refer to leisure trips but there is a portion of users that ride e-scooters for casual trips or commutes to and from work. Here, an electrical scooter network that covers the demand of the city of Thessaloniki is suggested. The implementation plan indicates three stages of construction up to the completion of the network. The construction operation is responsible for the creation and development of a sustainable network by adding approximately 20 stations at every stage. The capacity of the stations fluctuates between 3 and 20 parking spaces, which should accommodate e-scooters and preserve free spaces for potential riders. According to the characteristics of the city of Thessaloniki, its coverage requires the construction of 67 carefully distributed stations.

Shortest Path Algorithms for Pedestrian Navigation Systems

Efficient shortest path algorithms are of key importance for routing and navigation systems. However, these applications are designed focusing on the requirements of motor vehicles, and therefore, finding paths in pedestrian sections of urban areas is not sufficiently supported. In addition, finding the shortest path is often not adequate for urban sidewalk routes, as users of these applications may also be interested in alternative routes that, although slightly longer, possess other desirable features and properties. According to the literature, the search for alternative routes is carried out mainly using the k-shortest paths (KSP) algorithm which represents an ordered list of all available alternatives. Even though various KSP algorithms have been proposed, to the best of our knowledge, there is no research addressing all issues inherent in a pedestrian navigation system. The purpose of this paper is to present a heuristic algorithm for graph datasets that implements a penalty-based method which, by increasing certain edge weights, effectively searches for the most accessible alternative paths in multi-route cases. To demonstrate how the algorithm works, we present experimental results on finding the most accessible paths in pedestrian sections of the historical center of Thessaloniki city.

Evaluating the importance of urban green spaces: a spatial analysis of citizens' perceptions in Thessaloniki.

In Greek cities, urban green spaces are scarce and well below acceptable standards. However, policy makers and planners are not prioritizing long-term planning strategies for urban green and do not attempt to engage citizens in relevant decision-making and urban planning processes. In this context, a web-based public survey was conducted in the city of Thessaloniki (Greece) during the COVID-19 pandemic, aiming to identify citizens’ attitudes, satisfaction levels, actual behaviour and future expectations about urban green spaces (UGS). It also aimed to measure the effect of COVID-19 (mobility) restrictions on UGS visitation. All these issues were explored through a spatial lens, by developing measurable and mappable results suitable for future urban planning decisions. According to these results, citizens tend to report a very low satisfaction level about the current state of UGS (in terms of their adequacy and quality), and they tend to travel a great distance to reach an urban park (about 2 km on average). Moreover, the results indicate that spatial differences are very significant in terms of UGS availability and accessibility. Another important outcome of this study is that, unlike in other cities, the frequency of visiting green spaces in Thessaloniki did not increase during the pandemic. On the contrary, a slight downward trend was observed, maybe due to the combined effect of restriction measures and the lack of proximity/availability of UGS to local population groups. The maps produced in this study may thus facilitate well-informed planning decisions related to the development of new green projects.

An engineering geological database for managing, planning and protecting intelligent cities: The case of Thessaloniki city in Northern Greece

The challenge in intelligent cities is to recognize the benefits of using big data. The management of big datasets enables efficient data storage and processing to enhance information for the decision-making process. The key aim of this paper is to highlight how geological, engineering geological and geotechnical knowledge can be managed in a well-organized database, which is able to develop various correlations and to present useful information for both the design and construction stages of important projects of civil protection, municipality and technical companies.The present paper demonstrates the implementation of such work in the city of Thessaloniki, northern Greece, where a large amount of geological and geotechnical data for more than 600 boreholes, mainly based on borehole geological information, laboratory testing, geotechnical characterization and in situ field tests collected from fill, Quaternary and Neogene deposits, is stored in a georeferenced database. The presented database, is targeted to the management and processing of geo-engineering datasets for various geotechnical projects but also for the protection against natural hazards. The purpose of the approach, besides incorporating multisource datasets, is to provide a tool to effortlessly and immediately analyze, correlate and display data on maps, tables and diagrams for stakeholders. For this analysis, the present study proposes a geographic information system approach coupling the use of geostatistical techniques along with the cross validation to establish geotechnical zonation maps in order to highlight hazardous areas prone to liquefaction and settlement and to indicate the site's adaptability for different infrastructure projects.In that context, specific value ranges for several physical and mechanical properties are proposed from the assessment and correlation of the information originating from the database and spatial variability, providing geological and geotechnical knowledge in safe urban extensions suitable for construction in the research area environment. However, the key challenge is not only referring to provide each influencing parameter with a quantitative range of values, but also to establish a set of reliable structural and high-precision informative geotechnical models to comprehensively understand the superficial and subsurface conditions of the research area.

Spatiotemporal assessment of aeromycoflora under differing urban green space, sampling height, and meteorological regimes: the atmospheric fungiscape of Thessaloniki, Greece.

We studied the diversity and abundance of the airborne fungal spores in the city of Thessaloniki, Greece, for two consecutive years. Air samples were collected at one rooftop station (at 30m) and six near-ground stations (at 1.5m) that differed in the size and composition of adjacent green spaces. The effects of meteorological factors on airborne fungal spore concentrations were also explored. Cladosporium spores were dominant everywhere in the air of the city. The total concentration of the airborne fungal spores at 30m was 10 times lower than near the ground. Differences in concentration and composition were far less pronounced among near-ground stations. The attributes of the fungal spore season did not change in a consistent way among stations and years. Concentrations at the near-ground stations matched the grouping of the latter into stations of high, intermediate, and low urban greenspace. Minimum air temperature was the primary meteorological factor affecting spore abundance, followed by relative humidity. Airborne fungal spores are more homogeneously distributed in the air of the city, but their concentrations decrease more rapidly with height than pollen.

Active faults, Paleoseismological trenching and seismic hazard assessment in the Northern Mygdonia Basin, Northern Greece: The Assiros-Krithia fault and the Drimos fault zone

The Plio-Quaternary Mygdonia Basin in Northern Greece is bounded by active normal faults that can host significant earthquakes and produce considerable damage to the city of Thessaloniki (the second biggest city in Greece – 1 million population), located only 15–20 km away. In 1978, a damaging M = 6.5 earthquake occurred along a fault in the southern part of the basin, generating primary and secondary surface ruptures. This manuscript offers the results of the first detailed geomorphological and paleoseismological investigations in the northern part of the basin. As a result: i) a new active normal fault has been mapped, the Assiros-Krithia fault (AKF); and ii) another fault zone that has been assessed with probable activity in the literature, the Drimos fault zone (DFZ), has been confirmed active and mapped in detail. Paleoseismological trenching investigations supported by radiometric dating were carried out along both structures. The AKF and DFZ form the northern and northwestern boundaries of the Mygdonia Basin, respectively. The AKF deflects the local drainage network and is expressed as a single north dipping localised fault trace, gently uplifting the northern part of the Mygdonia Basin. The last event produced 48 cm of vertical displacement around 4540 cal. yrs BP, and the fault has an estimated slip rate of ∼0.1 mm/yr. The DFZ is an 8-10 km-long NW-SE trending normal fault that dips and downthrows to the NE (045o-050o). It is characterised by distributed deformation across eight major and secondary fault planes. Four of these planes have been activated over the last 9000 years, therefore the structure is Holocene active. The DFZ has an estimated slip rate of 0.1–0.3 mm/yr and may merged with the Liti-Gerakarou fault zone in multi-segment ruptures. The DFZ highlights that NW-SE trending faults are potentially active in Northern Greece. Their long recurrence intervals justify why they were not activated during the period covered by the historical record and emphasise, once again, the necessity of paleoseismological studies and the implementation of fault specific approaches in seismic hazard assessment.

Perceived Pedestrian Level of Service: The case of Thessaloniki, Greece

Level of Service (LOS) is one of the most crucial components for the assessment of pedestrian facilities by mainly concerning the effective width as well as pedestrians’ flows. However, current research reveals that qualitative characteristics can also contribute to LOS estimation as perceived by pedestrians. Specifically, socio-demographic characteristics (i.e., age, gender) as well as characteristics related with perceived comfort and safety can be related with perceived LOS. A Revealed Preference (RP) face to face questionnaire-based survey (including 301 interviewees) was realized during October 2019 at a central pedestrian facility in the city of Thessaloniki, Greece. RP questionnaire survey assisted in gaining valuable knowledge concerning the factors that mainly affect pedestrians’ perceived LOS across the pedestrian facility. The examined pedestrian facility is one of the most important in Thessaloniki since it facilitates high pedestrian flows within the city center daily. The present survey considered pedestrians’ general mobility characteristics such as walking frequency along the facility and trip purpose. Additionally, the evaluation of the greater facility’ area in terms of land use attractiveness, comfort, personal and road safety, public transport, parking conditions and traffic delays, accessibility, pedestrians and bicycles were concerned as well. Ordinal regression was the main tool for the development of the ordinal regression model, and therefore, for the conclusions’ drawing of the present research. The findings regarding perceived LOS can pave the way towards the design of sustainable policy concerning pedestrian facilities as well as the encouragement of active transport in urban areas.

Applying deep learning techniques for the prediction of pedestrian behaviour on crossings with countdown signal timers.

The improvement of road safety is considered as a top priority on the agendas of governments and transport policy making stakeholders worldwide, with the ‘Vision zero’ target being the pinnacle of the European Commission’s road safety strategy. Increased attention has been given to pedestrians, since crashes involving this vulnerable user group, have a higher mortality rate. As a result, research focusing on the behaviour of pedestrians and on the application of Intelligent Transport Systems that will assist pedestrians, is of increased importance. This paper attempts to predict pedestrian behaviour on crossings with a Countdown Signal Timer (CST), through the application of two machine learning algorithms. In the frame of the case study presented, an intersection in the Kalamaria city of Thessaloniki, Greece, where countdown signal timers have been installed on the pedestrian traffic lights, is analysed. For the needs of the analysis two models were implemented, a Deep Neural Network (DNN) and a Logistic Regression model. Results of both models indicated a satisfactory performance. In detail, the DNN model managed to estimate the pedestrians’ crossing speed with a Mean Squared Error value of 0.0647 (km/h)2, while the Logistic Regression model, which classified pedestrians based on their behaviour, achieved an accuracy of 97%. The accurate determination of pedestrians’ crossing behaviour could not only underline the influence of countdown signal timers, but also highlight appropriate countermeasures that can make infrastructure safer for this user group. Findings of this research can prove beneficial for researchers, infrastructure operators and policy makers alike, in their effort to improve the safety level of pedestrians.