154 research outputs found

    Recent coastline changes of fan-deltas in the Western Gulf of Corinth, Central Greece

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    Στην παρούσα εργασία επιχειρείται η εκτίμηση των πρόσφατων μεταβολών της ακτογραμμής των δελταϊκών ριπιδίων των ποταμών Φοίνικα, Θολοπόταμο, Λαγκάδι, Μεγανίτα, Σελινούντα, Κερυνίτη και Βουραϊκού, με τη χρήση μεθόδων τηλεπισκόπησης και ΣΓΠ. Τα δελταϊκά αυτά ριπίδια ηλικίας Ανώτερου Ολόκαινου έχουν σχηματισθεί από ποτάμια μεγάλης μορφολογικής κλίσης που αποθέτουν το αδρομερές φορτίο ιζημάτων τους κατά μήκος των νότιων ακτών του δυτικού Κορινθιακού κόλπου (Β. Πελοπόννησος). Για τους σκοπούς της εργασίας δημιουργήθηκε και οργανώθηκε μια ψηφιακή βάση δεδομένων για την περιοχή αποτελούμενη από λεπτομερή (κλίμακας 1:5.000) τοπογραφικά διαγράμματα και γεωμετρικά διορθωμένες και γεωαναφερμένες αεροφωτογραφίες λήψης 1945, 1996 και 2008. Η σύγκριση των ακτογραμμών των δελταϊκών ριπιδίων κατά τα έτη 1945, 1996 και 2008 οδήγησε στον προσδιορισμό των τμημάτων της ακτογραμμής πουυπόκεινται σε διάβρωση καθώς και εκείνων που προελαύνουν. Η κύρια διεργασία κατά μήκος του μεγαλύτερου μήκους της ακτογραμμής είναι η διάβρωση. Ομεγαλύτερος ρυθμός διάβρωσης ήταν 2,44 m/έτος (μεταξύ των ετών 1945 και 1996) και σημειώθηκε περίπου 150 m δυτικά των εκβολών του ποταμού Φοίνικα. Αντίθετα οι υψηλότεροι ρυθμοί προέλασης μετά το 1945 ήταν 3,10 και 3,00 m/έτος και σημειώθηκαν στις περιοχές των ενεργών εκβολών των ποταμών Βουραϊκού και Σελινούντα αντίστοιχα.This study deals with the assessment of recent shoreline change rates along the fandeltas of Finix, Tholopotamo, Lagadi, Meganitas, Selinous, Kerinitis, and Vouraikos streams by using GIS and Remote Sensing techniques. These Late Holocene fandeltas have been formed by high gradient braided streams that deposit their coarse sediment load along the southern coast (North Peloponnese) of the western Gulf of Corinth. For the purposes of the study a spatial database was constructed, organized and implemented consisting of analogue detailed (at the scale of 1:5000) topographic diagrams, and orthorectified aerial photos taken in 1945, 1996 and 2008. Comparisons of fan-deltas shoreline positions for the periods 1945 vs. 1996 and 1945 vs. 2008 were made and the segments of the coastline along the aprons of the fan-deltas which are subject to erosion accretion were defined. Coastal erosion is the main dominant geomorphic process along a significant part of the fan deltas coastline. The highest retreat rate value (2.44 m/yr for the period 1945-1996) was estimated for the Finix stream fan delta, about 150 m west of the river mouth, while the highest accretion rates since 1945 (3.10 and 3.00 m/yr) occurred at the mouths of Vouraikos and Selinous rivers respectively

    Crypto collectibles, museum funding and openGLAM: Challenges, opportunities and the potential of non-fungible tokens (NFTs)

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    Non-fungible tokens (NFTs) make it technically possible for digital assets to be owned and traded, introducing the concept of scarcity in the digital realm for the first time. Resulting from this technical development, this paper asks the question, do they provide an opportunity for fundraising for galleries, libraries, archives and museums (GLAM), by selling ownership of digital copies of their collections? Although NFTs in their current format were first invented in 2017 as a means for game players to trade virtual goods, they reached the mainstream in 2021, when the auction house Christie’s held their first-ever sale exclusively for an NFT of a digital image, that was eventually sold for a record 69 million USD. The potential of NFTs to generate significant revenue for artists and museums by selling effectively a cryptographically signed copy of a digital image (similar to real-world limited editions, which are signed and numbered copies of a given artwork), has sparked the interest of the financially deprived museum and heritage sector with world-renowned institutions such as the Uffizi Gallery and the Hermitage Museum, having already employed NFTs in order to raise funds. Concerns surrounding the environmental impact of blockchain technology and the rise of malicious projects, exploiting previously digitised heritage content made available through OpenGLAM licensing, have attracted criticism over the speculative use of the technology. In this paper, we present the current state of affairs in relation to NFTs and the cultural heritage sector, identifying challenges, whilst highlighting opportunities that they create for revenue generation, in order to help address the ever-increasing financial challenges of galleries and museums

    URBAN MICROCLIMATE IMPROVEMENT USING ENVI-MET CLIMATE MODEL

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    The aim of this paper is the modelling of urban microclimate, based on the limits imposed by the complexity of the three-dimensional space of cities. To this purpose, different Bioclimatic Scenarios were investigated through the microclimatic simulations using the micro-scale numerical model, ENVI-met 4v, applied in a case study of a Block in a highly residential neighbourhood of Athens. The study compares the bioclimatic scenarios of the roof top and road side vegetation plan in the current conditions, in order to evaluate how the existence of vegetation can affect the local air temperature and the thermal comfort condition of urban environment. This study also highlights the need to manage those microclimate data, through a geodatabase and provides a GIS approach of data organization and visualization. Creating building facades of the distributed temperature has showed that urban morphology parameters have an obvious impact on temperature distribution in the 3D space. On the other hand, the proposed roadside vegetation scenario has proved to be the most suitable way to improve the thermal comfort conditions of urban environment, as it can eliminate the Urban Heat Island (UHI) effects

    Assessment of neotectonic landscape deformation in Evia Island, Greece, using GIS-based multi-criteria analysis

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    This study deals with the assessment and mapping of neotectonic landscape deformation in the northern part of the Evia Island (Central Greece). Multi-Criteria Decision Analysis (MCDA) utilizing Analytic Hierarchy Process (AHP) andWeighted Linear Combination (WLC) procedures were conducted for the calculation of the Neotectonic Landscape Deformation Index (NLDI). The study is based on the combination of morphotectonic, geomorphological and geological parameters. The GIS-based spatial MCDA led to the classification of the study area into five classes of neotectonic deformation (from very low to very high) and to a neotectonic deformation map. The results were compared with the outputs of a relative tectonic activity classification approach based on quantitative geomorphic analysis at a regional scale, including site-specific field observations. Areas of high and very high deformation are related to the major active faults of Dirfis, Kandili and Gregolimano- Telethrio. Other minor active normal faults of medium to high seismic risk level, affecting the northern and northeastern parts of the island, are also associated with areas of intense landscape neotectonic deformation

    Exploring inter-organizational paradoxes: Methodological lessons from a study of a grand challenge

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    In this paper we outline a methodological framework for studying the inter-organizational aspects of paradoxes and specify this in relation to grand challenges. Grand challenges are large-scale, complex, enduring problems that affect large populations, have a strong social component, and appear intractable. Our methodological insights draw from our study of the insurance protection gap, a grand challenge that arises when economic losses from largescale disaster significantly exceed the insured loss, leading to economic and social hardship for the affected communities. We provide insights into collecting data to uncover the paradoxical elements inherent in grand challenges and then propose three analytical techniques for studying inter-organizational paradoxes: zooming in and out, tracking problematization, and tracking boundaries and boundary organizations. These techniques can be used to identify and follow how contradictions and interdependences emerge and dynamically persist within inter-organizational interactions and how these shape and are shaped by the unfolding dynamics of the grand challenge. Our techniques and associated research design help advance paradox theorizing by moving it to the inter-organizational and systemic level. This paper also illustrates paradox as a powerful lens through which to further our understanding of grand challenges

    Night-sky brightness monitoring in Hong Kong - a city-wide light pollution assessment

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    Results of the first comprehensive light pollution survey in Hong Kong are presented. The night-sky brightness was measured and monitored around the city using a portable light sensing device called the Sky Quality Meter over a 15-month period beginning in March 2008. A total of 1,957 data sets were taken at 199 distinct locations, including urban and rural sites covering all 18 Administrative Districts of Hong Kong. The survey shows that the environmental light pollution problem in Hong Kong is severe - the urban night-skies (sky brightness at 15.0 mag per arcsec square) are on average ~100 times brighter than at the darkest rural sites (20.1 mag per arcsec square), indicating that the high lighting densities in the densely populated residential and commercial areas lead to light pollution. In the worst polluted urban location studied, the night-sky at 13.2 mag per arcsec square can be over 500 times brighter than the darkest sites in Hong Kong. The observed night-sky brightness is found to be affected by human factors such as land utilization and population density of the observation sites, together with meteorological and/or environmental factors. Moreover, earlier night-skies (at 9:30pm local time) are generally brighter than later time (at 11:30pm), which can be attributed to some public and commercial lightings being turned off later at night. On the other hand, no concrete relationship between the observed sky brightness and air pollutant concentrations could be established with the limited survey sampling. Results from this survey will serve as an important database for the public to assess whether new rules and regulations are necessary to control the use of outdoor lightings in Hong Kong.Comment: 33 pages, 13 figures, Environmental Monitoring and Assessment, in pres

    Using Simulation to Assess the Opportunities of Dynamic Waste Collection

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    In this paper, we illustrate the use of discrete event simulation to evaluate how dynamic planning methodologies can be best applied for the collection of waste from underground containers. We present a case study that took place at the waste collection company Twente Milieu, located in The Netherlands. Even though the underground containers are already equipped with motion sensors, the planning of container emptying’s is still based on static cyclic schedules. It is expected that the use of a dynamic planning methodology, that employs sensor information, will result in a more efficient collection process with respect to customer satisfaction, profits, and CO2 emissions. In this research we use simulation to (i) evaluate the current planning methodology, (ii) evaluate various dynamic planning possibilities, (iii) quantify the benefits of switching to a dynamic collection process, and (iv) quantify the benefits of investing in fill‐level sensors. After simulating all scenarios, we conclude that major improvements can be achieved, both with respect to logistical costs as well as customer satisfaction

    Light pollution: The possible consequences of excessive illumination on retina

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    Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.Fil: Contin, Maria Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Benedetto, María Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Quinteros Quintana, María Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Guido, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin
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