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Physiology of Threespined Sticklebacks, Gasterosteux aculeatus, of the Camargue at different salinities / Capacités adaptatives d'écotypes d'épinoches marines et d'eau douce de MéditerranéeRind, Khalid Hussain 30 November 2018 (has links)
Les épinoches à 3 épines (Gasterosteus aculeatus), pêchées dans différentes régions de Camargue, ont été étudiées et soumises à différentes salinités. La pression osmotique du sang de poissons gardés en eau douce (FW : 5 ppm), en eau saumâtre (BW : 15 ppm) et en eau de mer (SW : 30ppm) était différente (147, 457 et 911 mOsmkg-1, respectivement). Cependant, les résultats de consommation d’oxygène montrent des valeurs similaires pour les poissons capturés dans la l’étang du Marteau (SW), le canal du Versadou (FW) et l’étang mésohalin (eau saumâtre) du Vaccarès (BW). Ainsi, ces épinoches peuvent rapidement s'acclimater à différentes salinités et se déplacer librement entre ces différents habitats avec des dépenses énergétiques limitées. Pour les épinoches du Vaccarès, le taux de consommation d'O2 diminue immédiatement après le transfert en FW jusqu'à 1 heure après transfert. L'activité branchiale Na+/ K+-ATPase (NKA) des épinoches collectées dans l’étang du Marteau et directement transférées en FW a révélé une augmentation significative 24h et 48h après le transfert (28% et 40%, respectivement). Cependant, l'activité NKA des branchies est réduite de manière significative de 36%, 24h suivant le transfert en SW.La morphologie corporelle des épinoches a également été étudiée mais des variations morphologiques limitées ont pu être observées. Le nombre moyen de plaques latérales est de 4,45 ± 0,31. Cependant, une différence morphologique significative est observée pour les branchiospines.Le marquage NKA a révélé des ionocytes avec différentes morphologies. Ces cellules sont également deux fois plus nombreuses chez les poissons FW que chez les poissons SW. Deux types d'ionocytes ont été identifiés chez les poissons FW: les cellules avec un dôme apical et les ionocytes avec une structure en nid d'abeille. Ces cellules sont bien des ionocytes du fait de leurs structures internes (présence de nombreuses mitochondries et d’un système tubulo-vésiculaire dense avec une membrane basale profondément invaginée). Chez les poissons acclimatés en SW, seuls des ionocytes avec une grande crypte apicale ont été observés le long des filaments branchiaux à la base des lamelles branchiales. Aucun ionocyte n'a pu être observé le long des lamelles branchiales. L'expression relative de l'ARNm de NKA α1 est apparue plus élevée dans les branchies des poissons acclimatés en SW que chez les poissons en BW. L’expression de la NKA α1b est significativement surexprimée dans les branchies des poissons SW par rapport aux poissons BW et FW. Cependant, pour la NKAα1a, les expressions relatives dans les branchies ne sont pas différentes selon la salinité. Pour l'expression du CFTR et de la V-ATPase, nous n'avons trouvé aucune différence significative. Par contre, NKCC1 est significativement plus élevé chez les épinoches acclimatées en SW.Les analyses histologiques du rein et le marquage de la NKA au niveau des tubules proximaux du rein n'ont révélé aucune différence pour les poissons en FW et en SW. Pour l'intestin, un fort marquage a été observé le long des membranes basolatérales des entérocytes. Cependant, là encore, nous n'avons observé aucune différence due aux conditions de salinité. Ces résultats suggèrent un haut niveau de plasticité pour ces organes.Globalement, ces résultats indiquent que les épinoches de Camargue sont homogènes au niveau morphologique et physiologique et possèdent de fortes capacités euryhalines. Cependant, des différences ont été identifiées au niveau des branchiospines entre les poissons capturés dans les habitats FW et les habitats BW/SW, probablement en raison de régimes alimentaires différents. Par conséquent, ces populations peuvent ne pas se mélanger même si les différents environnements aquatiques de Camargue sont interconnectés. / Threespined sticklebacks (Gasterosteus aculeatus) fished from different areas of the Camargue were studied and challenged to various salinity conditions. Blood osmotic pressures for fish kept in FW (5‰), BW (15‰) and SW (30‰) were different (147, 457 and 911 mOsm kg-1, respectively). However, oxygen consumption results revealed similar values for fish collected from the seawater Marteau lagoon (SW), the freshwater Versadou canal (FW) and the mesohaline/brackish water Vaccarès lagoon (BW). Therefore, sticklebacks of the Camargue can rapidly acclimate to different salinity conditions and move freely among these different habitats with limited energy expenditure. For sticklebacks from the Vaccarès lagoon, a significant reduction in O2 consumption rate occurred immediately after transfer to FW and up to 1h after transfer. The branchial Na+/K+-ATPase (NKA) activity of sticklebacks collected from the SW Marteau lagoon directly transferred from SW to FW, revealed a significant increase 24 h and 48 h after transfer (28% and 40%, respectively). However, gill NKA activity was significantly decreased by 36% within 24 h following immediate transfer to SW.Body morphology of sticklebacks was also studied but limited morphological variations could be observed for fish collected from different habitats. The average lateral plate number is 4.45±0.31. However, a significant morphological difference is observed for gill rakers.NKA labeling on histological sections revealed different ionocyte morphologies. In the gills of FW sticklebacks, ionocytes were observed along the gill filaments as well as the gill lamellae. Ionocytes were only identified along the gill filaments for SW fish. For SW fish, the ionocytes were round in shape and slightly smaller than the ionocytes of the FW fish. The ionocytes of the FW fish along the gill filaments were elongated but ionocytes along the gill lamellae were flattened and wider. Ionocytes were also twice more numerous for FW fish compared to SW fish.Also, two types of ionocyte were identified in FW fish: cells with an apical dome shape and ionocytes with a honeycomb-like structure. All these cell types were confirmed as ionocytes due to their internal structures filled with numerous mitochondria and a dense tubulo-vesicular system, with deeply invaginated basal membrane. In SW-acclimated fish, only ionocytes with a large apical crypt were observed along the gill filaments at the base of the gill lamellae. No ionocytes could be observed along the gill lamellae.Relative NKA α1 mRNA expression was higher in the gills of SW acclimated fish compared to BW fish and NKA α1b was significantly overexpressed in the gills of SW acclimated fish compared to the FW and BW fish. However, for NKAα1a, mRNA relative gene expressions in the gills are not different due to salinity. Whereas, for CFTR and V-ATPase expression, we did not find any significant difference. On the other hand, NKCC1 was significantly higher in SW acclimated sticklebacks.For sticklebacks kept in FW and for those acclimated to SW, analyses of histological sections from the kidney and NKA immunolabeling of the kidney proximal tubules revealed no difference. For the intestine, a strong immunofluorescence was observed along the basolateral membranes of the enterocytes for both the anterior and posterior intestine of FW and SW-acclimated sticklebacks but, again, we did not observe any difference due to salinity conditions. These results suggest a high level of plasticity for these organs.Altogether, these results indicate that sticklebacks of the Camargue area are morphologically and physiologically homogenous and have strong euryhaline capacities. Some differences were identified however for the gill rakers between fish collected from the FW and mesohaline / euryhaline habitats most probably due to different feeding regimes. Therefore, these fish populations may not mix even if the different Camargue aquatic environments are interconnected.
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Étude des amulettes de type égyptien et égyptisant et divers aegyptiaca de Carthage (septième jusqu'au deuxième siècle avant Jesus Christ) et de la Méditerrannée du premier millenaire avant Jesus ChristRedissi, Taoufik. January 1987 (has links)
Thesis (doctoral)--Université de Paris IV, 1987. / Summary in English.
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Rainfed orchards in semi-arid environments : retaining the water and the soilMeerkerk, André 05 September 2008 (has links)
The spatial distribution and properties of rainfed orchards in semi-arid environments result from complex interactions between man and the physical and economical environment. This thesis investigates a number of these interactions in the context of the mechanisation of management practices since the 1950's. It is shown how the practice of clean sweeping (i.e. frequent shallow tillage) influences the orchard water balance and how the removal of traditional soil and water conservation structures affects the connectivity of overland flow to the river system. Although clean sweeping prevents transpiration and competition by weeds, it also constrains the root growth in the plough layer, so that the trees cannot access the water from small rain events. In addition, clean sweeping promotes accelerated soil erosion. It appears that the practice of clean sweeping limits the water availability in orchards on loamy soils with an annual rainfall in the order of 300 mm. It is demonstrated that the presence and properties of rainfed orchards are related to spatial patterns of soil characteristics and climate. The observed decline in conservation structures like terraces and check-dams leads to an increase in the connectivity of water and sediment to the river system. An alternative for these traditional techniques to retain the water and the soil is the application of cover crops. The advantage of cover crops is that they do not limit the field size. A drawback in dry areas is the competition for water and nutrients between the cover crop and the trees. Field evidence and water balance simulations suggest that cover crops are feasible in areas with an annual precipitation of 500 mm or more.
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Gallo-Roman Relations under the Early EmpireWalsh, Ryan 25 August 2013 (has links)
This paper examines the changing attitudes of Gallo-Romans from the time of Caesar's conquest in the 50s BCE to the start of Vespasian's reign in 70-71 CE and how Roman prejudice shaped those attitudes. I first examine the conflicted opinions of the Gauls in Caesar's time and how they eventually banded together against him but were defeated. Next, the activities of each Julio-Claudian emperor are examined to see how they impacted Gaul and what the Gallo-Roman response was. Throughout this period there is clear evidence of increased Romanisation amongst the Gauls and the prominence of the region is obvious in imperial policy. This changes with Nero's reign where Vindex's rebellion against the emperor highlights the prejudices still effecting Roman attitudes. This only becomes worse in the rebellion of Civilis the next year. After these revolts, the Gallo-Romans appear to retreat from imperial offices and stick to local affairs, likely as a direct response to Rome's rejection of them.
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Will the Mediterranean Become "Too Hot" for Tourists?: A ReassessmentRutty, Michelle January 2009 (has links)
Numerous studies emphasize that climate, particularly temperature, is one of the most important resources of a tourist destination. With the onset of climate change, this climatic parameter of tourist destinations may change, leading some scientists and the media to claim that some destinations, including the Mediterranean, will become “too hot” for tourist comfort by as early as 2020 or 2030. This study examines tourists’ perceived and stated ideal and unacceptable conditions for multiple climate variables (temperature, rain, wind and sky conditions) for two popular Mediterranean tourism segments; beach/3S and urban sightseeing holidays. A survey instrument was administered to university students (n=866) in five countries that represent source markets for the Mediterranean (Austria, Germany, The Netherlands, Sweden and Switzerland). The survey results were applied to a baseline climate (1961-1990) and a minimum and maximum climate change scenario (A1B emission scenario for 2080-2099). With the exception of Athens, Greece, the results suggest that the media’s claims are erroneous, with only one urban destination incurring “unacceptably hot” conditions by mid-century and only a few destinations becoming “unacceptably hot” by the end of the 21st century. A more imminent threat could be the influence the media claims may have on tourists’ perception of the climate in the Mediterranean region. It is anticipated that these findings will hold important implications for critically assessing the potential impact of climate change in the study area and other destinations more broadly, and can be used to refine models intended to predict tourism demand and international tourism flows under climate change.
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Will the Mediterranean Become "Too Hot" for Tourists?: A ReassessmentRutty, Michelle January 2009 (has links)
Numerous studies emphasize that climate, particularly temperature, is one of the most important resources of a tourist destination. With the onset of climate change, this climatic parameter of tourist destinations may change, leading some scientists and the media to claim that some destinations, including the Mediterranean, will become “too hot” for tourist comfort by as early as 2020 or 2030. This study examines tourists’ perceived and stated ideal and unacceptable conditions for multiple climate variables (temperature, rain, wind and sky conditions) for two popular Mediterranean tourism segments; beach/3S and urban sightseeing holidays. A survey instrument was administered to university students (n=866) in five countries that represent source markets for the Mediterranean (Austria, Germany, The Netherlands, Sweden and Switzerland). The survey results were applied to a baseline climate (1961-1990) and a minimum and maximum climate change scenario (A1B emission scenario for 2080-2099). With the exception of Athens, Greece, the results suggest that the media’s claims are erroneous, with only one urban destination incurring “unacceptably hot” conditions by mid-century and only a few destinations becoming “unacceptably hot” by the end of the 21st century. A more imminent threat could be the influence the media claims may have on tourists’ perception of the climate in the Mediterranean region. It is anticipated that these findings will hold important implications for critically assessing the potential impact of climate change in the study area and other destinations more broadly, and can be used to refine models intended to predict tourism demand and international tourism flows under climate change.
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Augustus, Egypt, and PropagandaBroadbent, Valerie January 2012 (has links)
Augustus was a master of propaganda who employed Ancient and Hellenized Egypt as a means to legitimize his newly acquired power in Rome after the Battle of Actium. This thesis examines the ways in which Augustus moulded the people, imagery and religion of Egypt to suit his political needs. This was accomplished through an examination of the modified imagery of major Egyptian political figures such as Julius Caesar, Mark Antony, and Cleopatra VII. The symbolism of their images was altered to enhance Augustus’ standing in Rome. Augustus’ inspirations were also considered, namely Alexander the Great who became a significant influence for Augustus as was evident through the various similarities in their seal rings, family history, and the nature of both their roles as ‘restorers’ and ‘saviours’. The most predominant source for evidence of Augustus’ use of Egypt was found in his transportation of monumental obelisks from Egypt into the Circus Maximus and the Campus Martius. These monuments served to beautify the city while justifying Augustus’ authority in Rome. A close second to the transportation of the monumental architecture of Egypt was Augustus’ representation of the Battle of Actium upon his coinage. The battle was depicted typically with a tethered crocodile, stalks of wheat, a lituus, and a bareheaded Augustus. These actions augmented the prestige of Rome and presented Augustus as a powerful and reliable leader. In terms of religion, Augustus welcomed the practice of Egyptian cults while protecting the physical presence of Rome’s traditional religious core, the pomerium. This appealed to worshippers of both traditional and foreign cults and further enhanced his favour in Rome. Ultimately, Augustus’ actions served to increase his own prestige and credibility. This allowed Augustus to legitimize the authority of his rule and to initiate the beginnings of a stable Roman empire that would endure through Tiberius’ reign and those to follow.
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The Third Distinction of Michael Scot's Liber quattuor distinctionum: a window into the social world of astrologers in the early thirteenth centuryWheeler, Lillian January 2012 (has links)
Michael Scot remains an under-studied figure of the early thirteenth century, in particular with regard to his main original work, the Liber introductorius. This work has never been comprehensively edited, although several partial editions do exist. Scot's translations have received scholarly attention and their importance has been recognized, however, his original work has received a fairly negative assessment from scholars. A close look at one section of the Liber introductorius (Liber quattuor distinctionum, third distinction, CLM fols. 118rb-120ra), although it does conform to what scholars have found in other sections of Scot's work, offers another avenue of study; namely, the social historical aspects of astrology and astrologers in the early thirteenth century. Through his practical instructions to fledgling astrologers in matters such as their house, comportment, and dealings with customers, Scot provides us with a window into the social world of the astrologers of his time.
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A Study of Lead Ingot Cargoes from Ancient Mediterranean ShipwrecksBrown, Heather Gail 2011 August 1900 (has links)
Lead is often relegated to a footnote or sidebar in the study of ancient metals. However, the hundreds of lead ingots discovered in underwater sites over the past half-century have attested to the widespread production and trade of this utilitarian metal. Shipwreck sites allow independent dating evidence not available for many land find. They also provide information about shipment size as well as accompanying cargo which can offer clues about trade patterns and markets for lead in the ancient world. While lead was not particularly rare nor valuable, it represents small- to moderate-scale trade that bridges the gap between luxury trade and the circulation of staple agricultural products. It thus can be viewed as a proxy for the many other perishable materials that supported daily life, such as timber, cloth, cordage, leather and pigments.
Due to the abundance of lead ingot finds, published in many different languages with great variation in the details provided, it is difficult to compare all of this material. This thesis, therefore, compiles and presents data on all published lead ingots from Mediterranean and Atlantic shipwrecks through the fourth century C.E., in order to provide a framework to analyze the ancient seaborne lead trade. Sixty-eight sites containing lead ingots, lead ore or lead minerals are included in the analysis, divided into six time periods: Bronze Age, Archaic, Classical, Hellenistic, Roman Republic and Roman Empire. A typology of ingots has been developed to allow for comparison of ingots between wrecks. The uses of lead are reviewed, organized by type of use: domestic, professional, military and infrastructural. This allows insight into both the consumers in need of lead and the volume and regularity of consumption required for each use. An overview of lead production and its economic limitations further informs the discussion of the lead trade. The final analysis considers all of these factors in creating a picture of lead trade for each of the six periods, focusing on the regions of supply, the types of demand, and the dominant forces that drove the mining and production of lead.
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NATO's Mediterranean dialogue : challenges and prospects /Cayan, Umit N. January 2003 (has links) (PDF)
Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, December 2003. / Thesis advisor(s): David S. Yost, Donald Abenheim. Includes bibliographical references. Also available online.
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