No presente trabalho, suportes tridimensionais (scaffolds) de polímero reforçado foram gerados por meio da técnica aditiva por extrusão utilizando duas estratégias de deposição e, posteriormente, foram avaliados morfologicamente, mecanicamente e por meio de ensaios in vitro. Como matriz polimérica do compósito utilizou-se a poli(ε-caprolactona) e como reforço, o Biovidro® 45S5. De forma a melhorar a interação interfacial entre a matriz polimérica e a cerâmica, avaliou-se a incorporação de nanofibra de celulose ao biovidro. Os scaffolds foram fabricados seguindo dois métodos diferentes. O primeiro consistiu no pré-processamento do material em extrusora monorrosca, seguida de extrusão direta na impressora 3D experimental Fab@CTI. O segundo consistiu em um único processo de extrusão diretamente no cabeçote de extrusão. A caracterização química do biovidro por espectroscopia de fluorescência de raios-x mostrou eficiência na preparação da biocerâmica e a caracterização da distribuição do tamanho de partícula por espalhamento de luz dinâmica mostrou a obtenção de partículas submicrométricas. Os scaffolds foram caracterizados morfologicamente pela técnica de microscopia eletrônica de varredura, e, pôde-se notar a eficiência na fabricação de geometrias com arquitetura 00/900 e tamanho de poros adequado para a aplicação na engenharia tecidual. Os ensaios mecânicos de compressão evidenciaram melhoras na rigidez com o aumento do teor de biovidro, no caso dos materiais pré-processados por extrusão, além da influência da nanofibra de celulose na melhoria das propriedades mecânicas. Os ensaios biológicos in vitro mostraram que os scaffolds suportam proliferação celular e que o biovidro é responsável pela maior deposição de sais de cálcio extracelular, facilitando a interação do material sintetizado com o tecido ósseo. / In the present work, scaffolds of reinforced polymer were generated by means of the extrusion additive technique using two strategies of deposition and, later, were evaluated morphologically, mechanically and by means of in vitro tests. Poly (ε-caprolactone) was used as the polymer matrix of the composite and as a booster, Bioglass® 45S5. In order to improve the interfacial interaction between the polymer matrix and the ceramic, the incorporation of cellulose nanofiber to the bioglass was evaluated. The scaffolds were manufactured following two different methods. The first consisted of the pre-processing of the extruded extruder material followed by direct extrusion into the experimental Fab@CTI 3D printer. The second consisted of a single extrusion process directly on the extrusion head. The chemical characterization of the bioglass by x-ray fluorescence spectroscopy showed efficiency in the preparation of the bioceramics and the characterization of the particle size distribution by dynamic light scattering showed the submicrometric particles. The scaffolds were characterized morphologically by the scanning electron microscopy technique, and it was noted the efficiency in the manufacture of geometries with architecture 00/900 and pore size suitable for application in tissue engineering. The mechanical compression tests showed improvements in stiffness with increasing bioglass content in the case of pre-processed materials by extrusion, as well as the influence of cellulose nanofiber in improving mechanical properties. Biological assays have shown that scaffolds support cell proliferation and that bioglass is responsible for the increased deposition of extracellular calcium salts, facilitating the interaction of the synthesized material with the bone tissue.

O poli(ácido láctico) (PLA) é um polímero biodegradável, biocompatível e bioabsorvível proveniente de fontes renováveis. Constitui uma excelente alternativa sustentável para substituição dos polímeros provenientes de petróleo, atualmente dominantes no mercado industrial. Apesar das vantagens, o PLA tem baixa tenacidade e reduzida elongação na ruptura a temperatura ambiente, o que torna a sua utilização limitada em usos que necessitem de alta deformação plástica em níveis de exigência mecânicos elevados. Misturas mecânicas de PLA com polímeros altamente flexíveis, como é o caso da poli(ε-caprolactona) (PCL), podem resultar em novos materiais com propriedades mecânicas adequadas para diferentes aplicações. Blendas PLA/PCL são completamente imiscíveis, sendo seu comportamento mecânico altamente dependente da interação interfacial entre os componentes da blenda. Portanto, o objetivo desse trabalho é avaliar o efeito compatibilizante de um copolímero em bloco de baixa massa molar (2000 g mol-1) derivado de ε-caprolactona e policarbonato (C2) e, disponível comercialmente em blendas imiscíveis PLA/PCL. Blendas binárias e ternárias foram preparadas por mistura mecânica no estado fundido via processo de extrusão em rosca simples. O teor de PLA nas blendas foi de 75, 50 e 25% (em massa) e a concentração do copolímero de 0, 1, 3, 5 e 7% (em massa). O comportamento térmico, morfológico e mecânico das blendas compatibilizadas e não compatibilizadas foi avaliado por Calorimetria Exploratória Diferencial (DSC), Análise Termodinâmico-Mecânica (DMTA), Microscopia Eletrônica de Varredura (MEV) e ensaios de tração, flexão e impacto Izod. Os resultados de DSC e DMTA indicaram que o copolímero provocou pequena redução na temperatura de transição vítrea (Tg) do PLA, sugerindo que o C2 é solúvel no PLA. Entretanto, nas micrografias das superfícies de fraturas do PLA foi nítida a presença de pequenas micelas formadas pelo copolímero em bloco, indicando que há um limite de solubilidade do compatibilizante na fase de PLA. Os resultados obtidos em tração mostraram que com o aumento do teor de compatibilizante, a tensão no escoamento, a tensão na ruptura e o módulo elástico das blendas sofrem alterações. A propriedade de tenacidade, avaliada no ensaio de impacto Izod, mostrou que as blendas tiveram um ganho na resistência quando comparadas com o PLA puro. Os resultados mostraram que o copolímero em bloco derivado de ε-caprolactona e policarbonato alifático pode atuar como compatibilizante para blendas PLA/PCL / Poly(lactic acid) (PLA) is a biodegradable, biocompatible and bioabsorbable polymer from renewable sources. It is an excellent sustainable alternative for replacing petroleum polymers, currently dominant in the industrial market. Despite the advantages, PLA has low toughness and reduced elongation at room temperature, which makes its use limited in uses that require high plastic deformation under high mechanical stress levels. Mechanical mixtures of PLA with highly flexible polymers, such as poly(ε-caprolactone) (PCL), may result in new materials with mechanical properties suitable for different applications. PLA/PCL blends are completely immiscible, and their mechanical behavior is highly dependent on the interfacial interaction between the components of the blend. Therefore, the objective of this work is to evaluate the compatibilizing effect of a low molar mass block copolymer (2000 g mol-1) derived from ε-caprolactone and polycarbonate (C2) and commercially available in PLA/PCL immiscible blends. Binary and ternary blends were prepared by mechanical mixing in the melted state via single-screw extrusion process. The content of PLA in the blends was 75, 50 and 25% (% by mass) and the copolymer concentration was 0, 1, 3, 5 and 7% (% by mass). The thermal, mechanical and morphological behavior of compatibilized and non-compatibilized blends was evaluated by differential scanning calorimetry (DSC), thermodynamic-mechanical analysis (DMTA), scanning electron microscopy (SEM), tensile test, flexion test, and Izod impact. The results of DSC and DMTA indicated that the copolymer caused a small reduction in the glass transition temperature (Tg) of PLA, suggesting that C2 is soluble in PLA. However, in the micrographies of the fracture surfaces of the PLA the presence of small micelles formed by the block copolymer is clear, indicating that there is a limit of solubility of the compatibilizer in the PLA phase. The results obtained in a tensile test showed that with the increase of the compatibilizing content, the tension in the flow, the tension at rupture and the elastic modulus of the blends undergo changes. The tenacity property, evaluated in the Izod impact test, showed that the blends had a gain in resistance when compared to pure PLA. The results showed that block copolymer derived from ε-caprolactone and aliphatic polycarbonate can act as a compatibilizer for PLA/PCL blends.

O objetivo desse trabalho foi preparar compósitos de matriz de PCL reforçados com microfibrilas de PLA preparadas in situ a partir do controle da morfologia de blendas PLA/PCL. Embora a formação da morfologia fibrilar não tenha sido observada nas condições de extrusão empregadas, estudos do comportamento reológico de blendas de composição 50% PLA / 45% PCL / 5% de compatibilizante (% em massa) mostraram que microfibrilas de PLA podem ser obtidas entre 102 e 104 s-1. Assim, a técnica de reometria capilar foi utilizada para controlar a morfologia de blendas PLA/PCL. Compósitos de matriz de PCL reforçados com 5, 10, 20 e 30% (% em massa) de microfibrilas de PLA foram preparados em extrusora rosca simples, utilizando perfil de temperatura acima da temperatura de fusão do PCL, mas abaixo da temperatura de fusão do PLA, visando preservar a morfologia do PLA. O comportamento morfológico, térmico e mecânico dos compósitos foram avaliados por microscopia eletrônica de varredura (MEV), microscopia óptica com luz polarizada (POM), calorimetria exploratória diferencial (DSC), análise térmica dinâmico-mecânica (DMA) e ensaios mecânicos de tração e de impacto Izod. As curvas DSC mostraram um aumento no grau de cristalinidade da matriz de PCL com o aumento do teor de microfibrilas, o que provavelmente justifica os altos valores de módulo de Young determinados nos compósitos. A aplicação da Regra das Misturas comprovou que os compósitos fabricados exibiram boa orientação das microfibrilas na direção do esforço mecânico aplicado, com valores de módulos próximos ao limite superior da curva. No entanto, a adesão não uniforme entre a matriz e o reforço observada por MEV, resultou na queda da resistência à tração e resistência ao impacto dos compósitos, quando comparados ao PCL puro. A composição com 10% de microfibrilas apresentou um bom balanço de módulo de Young e resistência ao impacto, com potencial de viabilidade em uma série de aplicações biomédicas. / The aim of this work is to prepare PCL composites reinforced with PLA microfibrils prepared in situ from the morphology of PLA/PCL blends control. Although the formation of fibrillar morphology has not been observed under the extrusion conditions employed, studies of the rheological behavior of 50% PLA/ 45% PCL / 5% compatibilizer blends have shown that PLA microfibrils can be obtained between 102 and 104 s-1. Thus, the capillary rheometry technique was used to control the morphology of PLA /PCL blends. PCL composites reinforced with 5, 10, 20 and 30% (% by mass) PLA microfibrils were prepared in a single screw extruder using a temperature profile above the PCL melting temperature, but below the melt temperature of PLA, to preserve the PLA morphology. The morphology, thermal and mechanical behavior of the composites were evaluated by scanning electron microscopy (SEM), optical polarized light microscopy (POM), differential scanning calorimetry (DSC), dynamic mechanical-mechanical analysis (DMA) and mechanical tensile tests and Izod impact. DSC curves showed an increase in the degree of crystallinity of the PCL matrix with increasing the PLA microfibrils content, which probably justify the high Young\'s modulus values determined in the composites. The application of the Mix Rule proved that the composites showed good orientation of the PLA microfibrils in the direction of applied mechanical stress, presenting modules values near the upper limit of the curve. However, the non-uniform adhesion between the matrix and the reinforcement observed by MEV, caused the decrease of the tensile and impact strength when compared to pure PCL. The composition with 10% of PLA microfibrils exhibited a good balance of Young\'s modulus and impact strength, with potential viability in a number of biomedical applications.

No presente trabalho, suportes tridimensionais (scaffolds) de polímero reforçado foram gerados por meio da técnica aditiva por extrusão utilizando duas estratégias de deposição e, posteriormente, foram avaliados morfologicamente, mecanicamente e por meio de ensaios in vitro. Como matriz polimérica do compósito utilizou-se a poli(ε-caprolactona) e como reforço, o Biovidro® 45S5. De forma a melhorar a interação interfacial entre a matriz polimérica e a cerâmica, avaliou-se a incorporação de nanofibra de celulose ao biovidro. Os scaffolds foram fabricados seguindo dois métodos diferentes. O primeiro consistiu no pré-processamento do material em extrusora monorrosca, seguida de extrusão direta na impressora 3D experimental Fab@CTI. O segundo consistiu em um único processo de extrusão diretamente no cabeçote de extrusão. A caracterização química do biovidro por espectroscopia de fluorescência de raios-x mostrou eficiência na preparação da biocerâmica e a caracterização da distribuição do tamanho de partícula por espalhamento de luz dinâmica mostrou a obtenção de partículas submicrométricas. Os scaffolds foram caracterizados morfologicamente pela técnica de microscopia eletrônica de varredura, e, pôde-se notar a eficiência na fabricação de geometrias com arquitetura 00/900 e tamanho de poros adequado para a aplicação na engenharia tecidual. Os ensaios mecânicos de compressão evidenciaram melhoras na rigidez com o aumento do teor de biovidro, no caso dos materiais pré-processados por extrusão, além da influência da nanofibra de celulose na melhoria das propriedades mecânicas. Os ensaios biológicos in vitro mostraram que os scaffolds suportam proliferação celular e que o biovidro é responsável pela maior deposição de sais de cálcio extracelular, facilitando a interação do material sintetizado com o tecido ósseo. / In the present work, scaffolds of reinforced polymer were generated by means of the extrusion additive technique using two strategies of deposition and, later, were evaluated morphologically, mechanically and by means of in vitro tests. Poly (ε-caprolactone) was used as the polymer matrix of the composite and as a booster, Bioglass® 45S5. In order to improve the interfacial interaction between the polymer matrix and the ceramic, the incorporation of cellulose nanofiber to the bioglass was evaluated. The scaffolds were manufactured following two different methods. The first consisted of the pre-processing of the extruded extruder material followed by direct extrusion into the experimental Fab@CTI 3D printer. The second consisted of a single extrusion process directly on the extrusion head. The chemical characterization of the bioglass by x-ray fluorescence spectroscopy showed efficiency in the preparation of the bioceramics and the characterization of the particle size distribution by dynamic light scattering showed the submicrometric particles. The scaffolds were characterized morphologically by the scanning electron microscopy technique, and it was noted the efficiency in the manufacture of geometries with architecture 00/900 and pore size suitable for application in tissue engineering. The mechanical compression tests showed improvements in stiffness with increasing bioglass content in the case of pre-processed materials by extrusion, as well as the influence of cellulose nanofiber in improving mechanical properties. Biological assays have shown that scaffolds support cell proliferation and that bioglass is responsible for the increased deposition of extracellular calcium salts, facilitating the interaction of the synthesized material with the bone tissue.

Η υπό μελέτη περιοχή βρίσκεται στο δήμο Απολλώνιων, του νομό Λευκάδας. Το υπόβαθρο της αντιπροσωπεύεται δυτικά από την ανθρακική σειρά της ζώνης Παξών και κλαστικά ιζήματα. Η τεκτονική της χαρακτηρίζεται από ένα κατακερματισμένο, κλειστό αντίκλινο μεγάλης ακτίνας καμπυλότητας, τη μονάδα Λευκάτα. Ενώ η ανατολική πλευρά αποτελείται από την ασβεστολιθική σειρά της Ιόνιας ζώνης, το Φλύσχη και την Μειοκαινική Σειρά. Η σχέση μεταξύ αυτών των δύο ζωνών είναι ότι η δεύτερη είναι εφιππευμένη στην πρώτη. Στο πεδινό τμήμα πάνω στους προαναφερθείς σχηματισμούς αποτέθηκαν αλλουβιακές προσχώσεις. Στα πλαίσια της εργασίας αυτής πραγματοποιήθηκαν μετρήσεις στάθμης του ελεύθερου υδροφόρου του πεδινού τμήματος και δειγματοληψία από γεωτρήσεις, έτσι ώστε να μελετηθούν οι υδρογεωλογικές και υδροχημικές συνθήκες της περιοχής. Επίσης συλλέχθηκαν και αναλύθηκαν μετεωρολογικά δεδομένα ενώ κατασκευάστηκε γεωμορφολογικός χάρτης της με τη χρήση των γεωγραφικών συστημάτων πληροφοριών(GIS). / The study area, is located in the municipality of Apollonian, part of the prefecture of Lefkas. Its bedrock, to the western part consists of the carbonic sequence of Paxos Zone that is covered by clastic sediments.Its tectonics arecharacterized by a fragmented closed anticline, with large radius of curvature, called the unit Lefkata. While the eastern part consists of the series of carbonate formations of the Ionia Zone, the flysch formations and ends with the Miocene sequence. The relation between those two zones is that the second one is obducted over the first one. Finally above all those aforementioned formations, on the flat section recent alluvium were deposited. As part of this work, water levels were measured of the unconfined aquifer on the flat region and groundwater samplings have been taken, in order to define the hydrogeological and hydro-chemical conditions that prevail in the broader region. Furthermore, meteorological data of the area were collected and analyzed and in addition a geomorphological map of the area was constructed with the use of geographical information systems (GIS).

Cette thèse s’intéresse à la configuration des rapports qui existent entre la France, la Roumanie et la Serbie, réunies autour du Banat pendant la Grande Guerre. La perspective épistémologique est orientée par l’histoire de la Première guerre mondiale sous tous ses aspects: diplomatiques, militaires, culturels, discursifs, de la mémoire etc. Notre cadre d’analyse vise d’abord l’histoire régionale de la Grande Guerre parce que le territoire du Banat se relève à la fois comme une donnée des pourparlers diplomatiques et comme une réalité à l’issue de la guerre, comme un objet à réclamer par les Roumains et par les Serbes au nom du droit de propriété et comme un sujet à débattre en présence de l’aréopage de la paix. Tous ces traits sont étudiés en fonction de rapports diplomatiques, politico-militaires et de propagande de la Roumanie et de la Serbie (du Royaume des Serbes, Croates et Slovènes) avec la France, Paris étant la capitale du « Grand Allié » et le lieu vers lequel se livrent les attentes et les espérances de la réalisation de leur union nationale. / The aim of this thesis is to configure the relationships that have been established between France, Romania and Serbia on Banat during the First World War. Epistemological perspective is guided by the history of world conflict in all its aspects: diplomatic, military, cultural, discursive, memoirs, etc. Our analysis framework first aims the history of the great war, since the territory of Banat appears at the same time as a source of diplomatic negotiations and as a reality at the end of the conflict, as a territory claimed by the Romanians and Serbs on behalf of the right of ownership and as a topic of discussion within the peace forum. All these characteristics are studied regarding the diplomatic, political and military relations of Romania and Serbia (Kingdom of Serbs, Croats and Slovenes) with France, Paris being the capital of the "Great Ally” and the place that awaits the expectations and hopes of achieving their national union.

The traveling salesman problem (TSP) is defined as: given a finite number of cities along with the cost of travel between each pair of them, find the cheapest way of visiting all the cities only once and returning to your starting city. Some variants of TSP are proposed to visit cities depending on the profit gained when the visit occurs. In literature, these kind of problems are named TSP with profit. In TSP with profit, there are two conflicting objectives, one to collect profit and the other to decrease traveling cost. In literature, TSP with profit are addressed as single objective, either two objectives are combined linearly or one objective is constrained with a specified bound. In this study, a multiobjective approach is developed by combining &amp / #949 / -constrained method and heuristics from the literature in order to find the efficient frontier for the TSP with profit. The performance of approach is tested on the problems studied in the literature. Also an interactive software is developed based on the multiobjective approach.

Στο πλαίσιο της πτυχιακής εργασίας στο τομέα των γεωμορφικών εξελίξεων εξετάζονται η μελέτη και η περιγραφή της μορφογενετικής εξέλιξης της ευρύτερης περιοχής της λεκάνης του Πηνειού ποταμού στη Β.Δ. Πελοπόννησο.Ο Πηνειός ποταμός είναι άρρηκτα συνδεδεμένος με τον πέμπτο άθλο του Ηρακλή (καθαρισμός των στάβλων του Αυγεία από την κόπρο). Κατά τον μύθο, ο Ηρακλής, αφού γκρέμισε το μαντρότοιχο των στάβλων, εξέτρεψε τα ποτάμια Πηνειό και Αλφειό και καθάρισε τους στάβλους. Ο μύθος έχει συμβολικό χαρακτήρα και συνδέεται κυρίως με την κατασκευή υδραυλικών έργων, την αποξήρανση ελωδών εκτάσεων και την απαλλαγή της καλλιεργήσιμης γης από τα νερά των ποταμών. Το ποτάμι του Πηνειού βρίσκεται κοντά στο μυκηναϊκό νεκροταφείο της Αγίας Τριάδας, στην ορεινή ΒΑ Ηλεία, στα σύνορα με το Νομό Αχαΐα. Καταλαμβάνει μεγάλη έκταση στην κορυφή μιας πλαγιάς που καταλήγει απότομα στον Πηνειό ποταμό. Το νεκροταφείο αυτό της Αγίας Τριάδας δηλώνει την ύπαρξη κάποιου μεγάλου μυκηναϊκού πολιτισμού. Ο Πηνειός ανήκει στη Β.Δ. Πελοπόννησο με τις κύριες πηγές τροφοδοσίας του να πηγάζουν από το όρος Ερύμανθος (2224 μ.) σε υψόμετρο 1000 μ. Έχει συνολικό μήκος 70 χλμ. και η διεύθυνση αποστράγγισης του είναι από ΝΑ προς ΒΔ, όπου και εκβάλει στο Ιόνιο Πέλαγος. Η φυσική ροή του διακόπτεται από την παρουσία μιας τεχνητής λίμνης (ανθρωπογενές έργο) για αρδευτικούς σκοπούς προς το τέλος του μέσου ρου του ποτάμιου συστήματος. Πλησίον του χωριού Κέντρο έχει κατασκευασθεί φράγμα ύψους 50 μ. και μήκους 200 μ., όπου τα νερά του Πηνειού ταμιεύονται στην ομώνυμη τεχνητή λίμνη. Η προαναφερθείσα τεχνητή λίμνη κατασκευάστηκε το 1960 και σήμερα αποτελεί τη μεγαλύτερη λίμνη της Πελοποννήσου. Η λίμνη καλύπτει επιφάνεια 19,9 τ.χλμ. και βρίσκεται ανατολικά της αρχαίας Ήλιδας όπου χρησιμοποιείται για την άρδευση του κάμπου της Ηλείας. Στο μέσο ρου του Πηνειού και συγκεκριμένα στη τεχνητή λίμνη εκβάλουν ακόμη δύο σημαντικοί ποταμοί, ο Λάδωνας και ο Καλφαϊκός ποταμός (δευτερεύοντες πηγές τροφοδοσίας). / As part of the dissertation in the field of geomorphological evolutions are examined the research and the description of the geomorphological evolution in the wider area of the basin in Pineios river in the South West Peloponnisos. Pineios river is inextricably connected with the fifth labor of Hercules (where he had to clean Augeias stables from the dung). According to legend Hercules after he had brought down the walls of the stables he used his might to divert the rivers Pineios and Alfeios so that he could clean the stables. The myth is symbolic and is mainly linked with constructing hydraulic works, drying marshy areas and the discharge of arable land from river water. Near the river is located a mycenaean cemetery of Saint Τrinity in the mountainous north-east Hleia in the borders with Achaia. It occupies a large area on the slope which ends abruptly in Pineios river. This cemetery indicates the existence of the large Mycenaean civilization. Pineios belongs in the north-west Peloponnese with his main power sources to derive from mount Erymanthos (2224 m.) at an altitude of 1000 m. It has a total length of 70 km. and the address drain is from SE to NW where it empties into the Ionian Sea. It's natural flow is interrupted by the presence of an artificial lake (a manmade project) for irrigation purposes at the end of the middle reaches of the river system. Near the village Kentro a dam has been constructed 50 m. tall and 200 m. long, where the water of the river gathers in the homonymous artificial lake. This artificial lake was made in 1960 and today is the largest lake in Peloponnese. The lake covers an area of 19,9 km2 and is located east of ancient Hlida, where it is used to irrigate the plains of Hleia. In the middle reaches of Pineios and specifically in the artificial lake flow into two other major rivers, Ladwnas kai Kalfaikos river (secondary power sources).

Η παρούσα εργασία έχει ως σκοπό την ανάλυση μέσω αριθμοδεικτών που σχετίζονται με τις οικονομικές καταστάσεις των ξενοδοχειακών μονάδων της Ελλάδας. Η περίοδος μελέτης είναι το διάστημα 2009-2011, την περίοδο δηλαδή όπου η Ελλάδα διέρχονταν σε ύφεση και οικονομική κρίση. Για την ανάλυση λήφθηκαν υπόψη 60 ξενοδοχεία από διάφορες περιοχές της χώρας ώστε να καλυφθεί όσο το δυνατόν μεγαλύτερο γεωγραφικό μήκος. Σκοπός της εργασίας είναι να επιβεβαιώσει τις μελέτες του ΣΕΤΕ και του Παγκόσμιου Οργανισμού Τουρισμού, ότι ο ελληνικός τουρισμός κατά την διάρκεια της οικονομικής κρίσης υπέστη καθίζηση και οι εταιρίες του κλάδου λειτουργούσαν με ζημίες ή αναγκάζονταν σε παύση των λειτουργιών τους. / In the present essay an attempt is made in order to illustrate the impact of current economic crisis on the financial statements in hospitality sector in Greece. In order to accomplish this aim, 6 financial ratios of 60 hotels, for the period 2009-2011, were taken into account. The ratios measured are the liquidity, the solvency ratio, the ROA, the ROE, the profit margin and the debt ratio. The results showed that the business activity of Greek hotels have affected by the crisis, since in their majority have been recorded losses of the transactions or zero profits. The paradox of this study is that despite the economic crisis, the solvency ratio of Greek hotels is high enough.

Η υποβάθμιση της ποιότητας των υδάτων στην Ευρώπη οδήγησε στην έκδοση της Οδηγίας Πλαίσιο για τα Ύδατα 2000/60/ΕE, σύμφωνα με την οποία τα επιφανειακά ύδατα πρέπει να βρίσκονται σε «καλή οικολογική κατάσταση» έως το 2015. Τα υδρόβια μακρόφυτα αποτελούν ένα από τα τέσσερα βιολογικά ποιοτικά στοιχεία της Οδηγίας, τα οποία συμβάλλουν στην αξιολόγηση της οικολογικής ποιότητας. Η οικολογική κατάσταση εκφράζει την ποιότητα της δομής των υδάτινων οικοσυστημάτων και της λειτουργίας των φυτικών συναθροίσεων. Η εργασία αυτή πραγματοποιήθηκε το 2013 στα πλαίσια της μεταπτυχιακής μου διατριβής και εντάσσεται στην ευρύτερη ερευνητική προσπάθεια του Εργαστηρίου Οικολογίας του Πανεπιστημίου Πατρών, για την αξιολόγηση των ποτάμιων συστημάτων της Ελλάδας. Υλοποιήθηκε σε ποταμούς της Δυτικής Ελλάδας (Αλφειός, Πηνειός, Εύηνος και Νέδα), σε μια προσπάθεια εκτίμησης της περιβαλλοντικής τους κατάστασης σε όλο το μήκος τους, αλλά και το προσδιορισμό τυχών σχέσεων που μπορεί να είχαν μεταξύ τους. Οι δειγματοληψίες πραγματοποιήθηκαν το Καλοκαίρι του 2013 για τη συλλογή μακροφύτων ως βιολογικών δεικτών αλλά και δειγμάτων νερού για τον υπολογισμό φυσικοχημικών δεδομένων σύμφωνα με τα πρότυπα που έχει ορίσει η οδηγία 2000/60. Το πρόγραμμα παρακολούθησης περιλάμβανε: • Καταγραφή στο πεδίο φυσικοχημικών παραμέτρων του νερού, όπως βάθος (m), ταχύτητα ροής (km/h), θερμοκρασία (οC), αγωγιμότητα (mS/cm), διαλυμένο οξυγόνο (mg/l), pH, ολικά διαλυμένα στερεά (mg/l). • Στο εργαστήριο πραγματοποιήθηκαν χημικές αναλύσεις δειγμάτων νερού, οι οποίες περιλαμβάνουν τον υπολογισμό της αλκαλικότητας (mg/l), της συγκέντρωσης των θρεπτικών αλάτων φωσφόρου-SRP(μg/l), ΤP (μg/l), αζώτου- NO2-N (μg/l), NO3-N (μg/l) και ΝΗ4-Ν (μg/l) και ολικού αζώτου (ΤΝ) (μg/l). • Στο πεδίο συλλέχτηκαν ποσοτικά και ποιοτικά δεδομένα που αφορούν τη δομή των μακροφυτικών κοινωνιών, καθώς και τη χωρική διακύμανση της κατανομής και της ανάπτυξης των μακροφύτων. Για τις εργασίες πεδίου χρησιμοποιήθηκαν φορητά πολυπαραμετρικά όργανα, δειγματολήπτες νερού, ενώ για τις χημικές αναλύσεις φασματοφωτόμετρο και αναλυτές ολικού αζώτου της Shimadzu στο Εργαστήριο. Επίσης καταγράφηκαν οι ανθρωπογενείς πιέσεις που ασκούνται στη λεκάνη απορροής των ποταμών, οι τροποποιήσεις της φυσικής μορφολογίας τους, οι χρήσεις γης καθώς και οι ανθρωπογενείς δραστηριότητες στην περιοχή. Κατά την επεξεργασία των δεδομένων στο εργαστήριο πραγματοποιήθηκε ανάλυση των πιέσεων της περιοχής μελέτης με τη χρήση του πλαισίου DPSIR σύμφωνα με το οποίο εντοπίστηκαν και αξιολογήθηκαν οι πιέσεις που δημιουργούν τις σημαντικότερες επιπτώσεις στις λεκάνες απορροής. Αποτέλεσμα της μεθόδου ήταν πως η εκτεταμένη γεωργία είναι αυτή που δημιουργεί τις μεγαλύτερες επιπτώσεις στον κάτω ρου των ποταμών ενώ τα λιγνιτοεργοστάσια της Μεγαλόπολης επιβαρύνουν σε πολύ σημαντικό βαθμό τον Αλφειό στο σύνολό του. Από τη στατιστική επεξεργασία έγινε μια προσπάθεια ομαδοποίησης των σταθμών δειγματοληψίας ανάλογα με την ομοιότητά τους σε βιοτικούς και αβιοτικούς παράγοντες με τη χρήση της Ανάλυσης Ιεραρχικής Ομαδοποίησης (Cluster analysis). Από τη συγκεκριμένη ανάλυση προέκυψε μεγάλη ομοιότητα του κάτω ρου των ποταμών και σαφής διαφοροποίηση του άνω ρου του Αλφειού εξαιτίας του εργοστασίου της Δ.Ε.Η στη Μεγαλόπολη. Στη συνέχεια με τη χρήση της Ανάλυσης Κυρίων Συνιστωσών (PCA) και της Ανάλυσης Κανονικών Αντιστοιχιών (CCA) πραγματοποιήθηκε συσχετισμός των βιοτικών και αβιοτικών παραμέτρων των περιοχών μελέτης. Τέλος χρησιμοποιήθηκε ο δείκτης με υδρόβια μακρόφυτα IBMR (Macrophytes Biological Index for Rivers) για την εκτίμηση της οικολογικής ποιότητας των ποταμών. Από τα αποτελέσματα προέκυψε πως οι ποταμοί της Δυτικής Ελλάδας παρουσιάζουν μειωμένη παραγωγικότητα σε υδρόβια μακρόφυτα τόσο λόγω της επιβάρυνσης των ποταμών όσο και εξαιτίας της μεγάλης ταχύτητας ροής του νερού που δεν επιτρέπει την ανάπτυξη μακροφύτων στην κοίτη και τα κράσπεδα των ποταμών. Εν κατακλείδι η παρούσα μελέτη πραγματοποιήθηκε στα πλαίσια της Οικολογικής Αξιολόγησης των Υδάτινων Συστημάτων της Ελλάδας και κατάφερε να πετύχει του στόχους οι οποίοι είχαν τεθεί. Αποτέλεσε ένα σημαντικό διαχειριστικό εργαλείο καθώς έθεσε τις βάσεις για ένα ολοκληρωμένο δίκτυο παρακολούθησης των ποταμών της Δυτικής Ελλάδας. Εκτίμησε την οικολογική αλλά και τη χημική κατάσταση των οικοσυστημάτων όπως επίσης και τις πιέσεις στις οποίες υφίστανται αλλά και τις επιπτώσεις που προκαλούνται από αυτές. Τέλος αποτελεί έναυσμα για περαιτέρω παρακολούθηση των περιοχών αυτών αλλά και εκτίμηση της οικολογικής κατάστασής τους μακροπρόθεσμα. / The degradation of water quality in Europe has forced the European Parliament to adopt the Water Framework Directive 2000/60/EC which insists that EU member states achieve "good ecological status" of surface waters by 2015. Aquatic macrophytes are one of the four biological quality elements of the Directive, for the assessment of ecological quality. The ecological status represents the quality of the structure of aquatic ecosystems and the function of plant assemblages. The present inquiry was carried out in 2013 for my master thesis and is part of the research of the Laboratory of Ecology of the University of Patras for the evaluation of river systems in Greece. The purpose of the present study was to estimate the environmental status of the rivers of Western Greece (Alfeios, Pineios, Evinos, Neda) and to correlate their condition. During summer 2013, sampling was performed to collect macrophytes as biological indicators and water samples to calculate physicochemical data according to the standards of Directive 2000/60. The monitoring included: • Recording of physicochemical parameters of water, such as depth (m), flow velocity (km/h), temperature (oC), conductivity (mS/cm), dissolved oxygen (μg/l), pH and total dissolved solids (μg/l). • Chemical analysis of water samples in the lab, which include measurement of alkalinity (μg/l) and concentration of nutrients phosphorus-SRP (μg/l), total phosphorus TP (μg/l), nitrogen-NO2-N, NO3-N and NH4-N (μg/l) and total nitrogen (TN). • Collection of qualitative and quantitative data in the field concerning the structure of the macrophytic societies and the spatial variation of their distribution and development. For the field study, portable multiparameter devices and water samplers were used, whereas for the chemical analysis in the lab, spectrophotometer and Shimadzu total nitrogen analyzer were used. In addition, human pressure on drainage basin of the rivers, the changes to natural topography, the land use and the human activities in the region were recorded. For the data analysis and interpretation, DPSIR was used to analyze the pressures in the study area and evaluate which ones interfere more in the river basins. The results demonstrated that extensive agriculture cause the greatest damage in the lower course of the rivers and the lignite power plants of Megalopoli pollute river Alfeios. Moreover, cluster analysis was used to group the water samples regarding their resemblance in biotic and abiotic factors. The results indicate great similarity of the lower courses of the rivers and differentiate the upper course of Alfeios because of the presence of power station in Megalopoli. Principal component analysis (PCA) and canonical correlation analysis (CCA) were performed to correlate the biotic and abiotic factors of the study area. IBMR (Macrophytes Biological Index for Rivers) was also used to evaluate the ecological status of the rivers. The results show that the rivers of Western Greece present a low output in macrophytes because of the pollution of the rivers and the high speed flow of water that prevents the development of macrophytes in riverbed and river side curb. To sum up, the present study was conducted for the Ecological Evaluation of Aquatic ecosystems in Greece and succeeded the goals. It has been a management tool to set the basis for a network to monitor the rivers of Western Greece. It has accessed the ecological and chemical status of ecosystems, as well as the pressures that exist and the effects caused by them. Finally, it has been a trigger for further monitoring of these areas and assessment of the ecological status in the long term.