991 resultados para Plateau zokor ( Myospalax bailey)
Resumo:
The objective of this work was to evaluate hematological, biochemical and ruminant parameters for diagnosis and treatment of the left displaced abomasum (LDA) in dairy cows, in the Plateau Region of Rio Grande do Sul, Brazil. Ruminant fluid, blood and urine samples were collected from 20 cows suffering LDA and from 20 healthy cows (control). The cows with LDA showed lower values of daily milk production, body weight and corporal condition score. The use of pH reagent strips showed to be functional in the field, when compared to a digital pH meter. Ruminant dynamics was damaged in cows affected by LDA, as it was evidenced by the higher reduction time of methylene blue. Serum values of lactate, beta-hydroxybutyrate, urea, albumin, free fatty acids and cholesterol shows to be auxiliary tools in the LDA characterization.
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The appearance of immunoreactive alpha-melanotropin (alpha-MSH) and adrenocorticotropin (ACTH) during development was studied in 3 areas of the rat brain--cerebral hemispheres, midbrain and hindbrain--from embryonic day (ED) 13-14 until day 21 postnatally. The alpha-MSH content in vivo was always highest in the midbrain; a peak content at birth was followed by a transient decline and a later, higher plateau from postnatal day 7 onwards. The alpha-MSH content in the cerebral hemispheres rose progressively after birth reaching a peak at day 21. Values in the hindbrain rose at day 3 and changed relatively sue taken at ED 15-16 showed a gradual increase in alpha-MSH content over the 20 days. The alpha-MSH content of hindbrain cultures remained at constant low levels, while no alpha-MSH was detectable in cerebral hemisphere cultures. ACTH appeared in vivo earlier than alpha-MSH and was detectable in embryonic brains at ED 13-14. A transient rise was seen at ED 17-18 and major peaks at birth, day 2 and day 3, in the midbrain, hemispheres and hindbrain, respectively. In vitro, the ACTH content increased in all brain regions during the first 5 days in culture and showed no further change thereafter. Comparisons of the in vivo and in vitro development of alpha-MSH and ACTH demonstrate that (i) these two peptide systems are independent in respect to their localization and time of appearance; (ii) they undergo maturation both in vivo and in vitro; (iii) epigenetic factors, such as interactions with other neurotransmitter systems may modulate the developmental pattern of these two peptides.
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Residual lung function abnormalities have been investigated in 9 children (4 boys and 5 girls) a mean 2.7 years after surviving severe adult respiratory distress syndrome (ARDS). All patients had been artificially ventilated for an average of 9.4 days with a FiO2 greater than 0.5 for 34 hours and maximal PEEP levels in the range of 8-20 cm H2O. Since the ARDS, 3 children had presented recurrent respiratory symptoms (moderate exertional dyspnea and cough) and 2 had had evidence of fibrosis on chest radiographs. In all patients abnormal lung functions were found, i.e. ventilation inequalities (8), hypoxemia (7), and obstructive (2) and restrictive (1) lung disease. A significant correlation between respirator therapy and residual lung function was found (duration of FiO2 greater than 0.5 in hours and inspiratory plateau pressure during respirator therapy vs. ventilation inequalities and hypoxemia).
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The aim of this study was to investigate the relationships between plasma concentrations of losartan, an orally active angiotensin II inhibitor, its active metabolite EXP3174, and angiotensin II blockade. Six healthy subjects received single oral doses of 40, 80, or 120 mg losartan and placebo at 1-week intervals in a crossover study. Angiotensin II blockade was assessed by the blood pressure response to exogenous angiotensin II before and after losartan administration. EXP3174 reached higher plasma concentrations and was eliminated more slowly than its parent compound; its levels paralleled the profile of angiotensin II blockade closer than losartan. Inhibition of the pressure response was dose dependent. The Hill-shaped relationship between response and EXP3174 concentration (or time-integrated variables) approached a plateau with 80 mg. The dose-dependent increase in plasma renin and angiotensin II exhibited a considerable individual scatter. We conclude that losartan produces a dose-dependent, effective angiotensin II blockade that is largely determined by the active metabolite EXP3174.
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Abstract The Northwestern edge of the modern Caribbean Plate, located in central Middle America (S-Guatemala to N-Costa Rica), is characterized by a puzzle of oceanic and continental terranes that belonged originally to the Pacific faade of North America. South of the Motagua Fault Zone, the actual northern strike slip boundary of the Caribbean Plate, three continental slivers (Copn, Chortis s. str. and Patuca) are sandwiched between two complex suture zones that contain HP/LT mafic and ultramafic oceanic rocks: The Motagua Mlanges to the North, extensively studied in the last ten years and the' newly defined Mesquito Composite Oceanic Terrane (MCOT) to the South. No modem geological data were available for the oceanic terrane located in the southern part of the so called continental "Chortis Block". Classically, the southern limit of this block with the Caribbean Large Igneous Province (CLIP) was placed at a hypothetical fault line connecting the main E-W fault in the Santa Elena Peninsula (N-Costa Rica) with the Hess Escarpment. However, our study in eastern Nicaragua and northwestern Costa Rica evidences an extensive assemblage of oceanic upper mantle and crustal rocks outcropping between the Chortis/Patuca continental blocks and the CLIP. They comprise collided and accreted exotic terranes of Pacific origin recording a polyphased tectonic history. We distinguish: 1- The MCOT that comprises a Late Triassic to Early Cretaceous puzzle of oceanic crust and arc-derived rocks set in a serpentinite matrix, and 2- The Manzanillo and Nicoya Terranes that are made of Cretaceous plateau-like rocks associated with oceanic sediments older than the CLIP. This study has been focused on the rocks of the MCOT. The MCOT comprises the southern half of the former "Chortis Block" and is defined by 4 comer localities characterized by ultramafic and mafic oceanic rocks of Late Triassic, Jurassic and Early Cretaceous age: 1- The Siuna Serpentinite Mlange (NE-Nicaragua), 2- The El Castillo Mlange (Nicaragua/Costa Rica border), 3- DSDP Legs 67 and 84 (Guatemala fore-arc basin), and 4- The Santa Elena Peridiotite (NW-Costa Rica). The Siuna Serpentinite Mlange (SSM) is a HP/LT subduction zone mlange set in a serpentinite matrix that contains oceanic crust and arc-related greenschist to blueschist/eclogite facies metamafic and metasedimentary blocks. Middle Jurassic (Bajocian-Bathonian) radiolarites are found in original sedimentary contact with arc-derived greenstones. Late Jurassic black detrital chert possibly formed in a marginal (fore-arc?) basin shortly before subduction. A phengite 40Ar/39Ar -cooling age dates the exhumation of the high pressure rocks as 139 Ma. The El Castillo Mlange (ECM) is composed of serpentinite matrix with OIB metabasalts and Late Triassic (Rhaetian) red and green radiolarite blocks. Recent studies of the DSDP Legs 67/84 show that the Guatemala/Nicaragua fore-arc basin is composed of a pile of ultramafic, mafic (OIB-like) and arc related rocks with ages ranging from Late Triassic to Campanian. Finally, the Santa Elena peridiotites that mark the limit of the MCOT with the Manzanillo/Nicoya Terranes and correspond to an association of ultramafic rocks that comprise peridiotites, dunites and chromites of abyssal and fore-arc origin. The SSM is the result of a collision between a Middle Jurassic island arc and the Patuca Terrane, a fragment of the Western N-American active continental margin. The Siuna Mlange (SSM) and the South Montagna Mlange share common characteristics with the Pacific N-American suture zone (E-Franciscan and Vizcaino mlanges), in particular, the Mesozoic ages of HP/LT metamorphic and the arc-derived blocks. For us, these mlanges imply an originally continuous, but slightly diachronous suture that affected the entire W-American active margin. It may imply the arrival and collision of an exotic intraoceanic arc (Guerrero-Phoenix) related to the origin of the Pacific Plate that initiated as a back arc basin of this arc. The present disposition of the fragments of this suture zone is the result of a northward shift of the active left-lateral strike slip motion between the N-American and the Caribbean Plates. Rsum Le coin nord-ouest de la Plaque Carabe moderne se trouve en Amrique Centrale, entre le sud du Guatemala et le nord du Costa Rica. Cette rgion est compose d'un puzzle de terrains ocaniques et continentaux dont les origines se situent sur la faade pacifique de l'Amrique du Nord. Au sud de la faille de Motagua, la limite septentrionale actuelle, dcrochante, de la Plaque Carabe, se trouvent 3 copeaux continentaux (Copn, Chortis s. str. et Patuca) coincs entre deux zones de suture complexes roches mafiques et ultramafiques qui ont subi un mtamorphisme de haute pression/basse temprature (HP/LT). Il s'agit des Mlanges de Motagua au nord, largement tudis ces dernires annes, et du Mesquito Composite Oceanic Terrane (MCOT), rcemment dfini par nous, au sud. En vue de l'absence de donnes gologiques modernes concernant les terrains ocaniques qui se trouvent dans la partie sud du "Chortis Block" considre comme continentale, nous avons ddi cette tude cette rgion. Classiquement, la limite mridionale entre le "Chortis Block" et la "Caribbean Large Igneous Province" (CLIP) a t associe une faille hypothtique reliant la faille E-W de Santa Elena (nord du Costa Rica) l'Escarpement de Hess. Notre tude au Nicaragua oriental et au Costa Rica nord-occidental a rvl l'existence de larges terrains composs d'assemblages de roches mantliques et ocaniques qui se placent entre les blocs continentaux Chortis/Patuca et le CLIP. Ces assemblages rvlent des terrains collisionns et accrts d'origine pacifique enregistrant une histoire tectonique polyphase. Nous distinguons: 1- Le MCOT, un puzzle de roches ocaniques d'arc d'ge Triassique suprieur au Crtace infrieur, 2- Les terrains de Manzanillo et de Nicoya, des morceaux de plateaux ocaniques associs des sdiments ocaniques plus gs que le CLIP. Cette tude se focalisera sur les roches du MCOT. Le MCOT occupe la moiti sud de l'ancien "Chortis Block" et peut se dfinir par 4 localits de rfrence qui montrent des roches mafiques et ultramafiques ocaniques d'ges compris entre le Trias suprieur et le Crtace infrieur. 1- Le Siuna Serpentinite Mlange (NE-Nicaragua), 2- Le El Castillo Mlange (Nicaragua/Costa Rica border), 3- Le DSDP Legs 67/84 (Guatemala fore-arc basin) et 4- La Santa Elena Peridiotite (nord-ouest du Costa Rica). Le Siuna Serpentinite Mlange (SSM) est un mlange de subduction HP/BT dans une matrice de serpentinite. On y trouve des lments de crote ocanique et d'arc insulaire en facis de schistes verts et schistes bleus. Des radiolarites du Jurassique moyen se trouvent en contact sdimentaire sur des roches vertes d'arc. En revanche, des cherts noirs dtritiques datent du Jurassique suprieur et sont probablement issus d'un bassin marginal (fore-arc ?) peu avant leur subduction, car un ge 40Ar/39Ar de refroidissement des phengites date l'exhumation des roches de haute pression 139 Ma. Le Mlange d'El Castillo (ECM) est constitu d'une matrice serpentinitique et contient des blocs de metabasaltes OIB et des blocs de radiolarites du Trias terminal. Des tudes rcentes ont repris les roches fores lors des DSDP Legs 67 et 84 et montrent que le soubassement du bassin d'avant-arc du Guatemala-Nicaragua est compos de roches ultramafiques et mafiques (OIB et arc), dont les ges isotopiques vont du Trias au Crtac suprieur. Finalement, les pridiotites de Santa Elena forment la limite sud du MCOT par rapport aux terrains de Manzanillo et Nicoya. Elles contiennent des serpentinites et localement des dunites et chromites affinit abyssale et de fore-arc. Le SSM tmoigne d'une collision entre un arc insulaire d'ge Jurassique moyen et le Patuca Terrane, un fragment de la marge active nord-amricaine. Le SSM et le South Motagua Mlange ont des caractristiques en commun avec les zones de suture de la faade pacifique de l'Amrique du nord (E-Franciscan et Vizcaino mlanges), notamment les ges Msozoques du mtamorphisme HP/BT et les blocs de roches d'arc. Ce fait nous conduit penser qu'il s'agit d'une grande zone de suture qui tait l'origine continue sur toute la marge ouest-amricaine, mais lgrement diachrone. Cette suture implique l'arrive et la collision d'un arc intraocanique exotique (Guerrero-Phoenix) qui est l'origine de la Plaque Pacifique qui s'ouvrait en back arc par rapport celui-ci. La disposition actuelle des fragments de cette suture est due la migration vers le nord du dcrochement actif senestre entre la Plaque nord-amricaine et la Plaque Carabe. K. Flores, 2009 Mesozoic oceanic terranes of southern central America Rsum Grand Public La prsente thse est le rsultat de travaux de terrain effectus de 2005 2008 au nord-est et au sud du Nicaragua et au nord du Costa Rica, en Amrique Centrale, des analyses ptrologiques et gochimiques en laboratoire ainsi que de la modlisation de l'volution godynamique. La rgion tudie se situe en bordure nord - ouest de la Plaque Carabe moderne. Dans la majorit des publications rcentes cette rgion est reprsente comme un vaste bloc continental (le "Bloc Chortis") qui serait limit, (i) au nord, par la faille dcrochante de Motagua, la limite actuelle entre la Plaque Nord-Amricaine et la Plaque Carabe, et (ii) au sud, par une suture hypothtique qui se trouverait aux confins entre le Nicaragua et le Costa Rica. La rgion du Costa Rica a t considre presque entirement comme une partie du Plateau Carabe ("Caribbean Large Igneous Province" (CLIP)). L'tude dtaille des affleurements nous a permis de mettre en vidence : - Au nord-est du Nicaragua (Siuna) : Des roches ocaniques dates du Jurassique moyen, grce aux faunes radiolaires qui ont t extraites des radiolarites rouges. Ces roches ont subi un mtamorphisme de haute pression typique des zones de collision. L'tude radio-isotopique Ar/Ar a permis de dater la collision du Crtac basal (139 Ma). - Au sud du Nicaragua : Des roches ocaniques d'ge Trias terminal (200 millions d'annes), galement dates l'aide de faunes radiolaires. Il s'agit actuellement des roches ocaniques les plus anciennes connues de l'Amrique Centrale. - L'tude gochimique et les ges des fossiles dmontrent que le tiers septentrional du Costa Rica possde un soubassement construit d'au moins deux terrains (Nicoya et Manzanillo), qui ont des caractristiques de Plateau ocanique (Nicoya) et d'arc volcanique du Crtac moyen (Manzanillo). Ces deux terrains sont plus anciens que le CLIP. En conclusion, nous constatons que la rgion tudie est constitue d'un puzzle de 3 blocs continentaux et d'un vaste terrain ocanique composite que nous appelons Mesquito Composite Oceanic Terrane (MCOT). En plus, nous dfinissons les terrains de Nicoya et de Manzanillo comme plus gs et distincts du CLIP. Le MCOT est caractris par la prsence de roches du manteau suprieur (les serpentinites) et de la crote ocanique, ainsi que des morceaux d'arcs, d'ge allant du Trias suprieur au Crtac. Ce terrain est comparable d'autres zones de suture de la faade pacifique de l'Amrique du nord, notamment en ce qui concerne les ges Msozoques, le mtamorphisme de haute pression et l'association de roches mantliques et crustales ocaniques. Ce fait nous conduit penser qu'il s'agit d'une grande zone de suture qui tait l'origine continue sur toute la marge ouest-amricaine. Cette suture implique l'arrive et la collision d'un arc infra-ocanique exotique qui serait l'origine de la Plaque Pacifique qui se serait ouverte en bassin d'arrire arc par rapport celui-ci. La disposition actuelle des fragments de cette suture est due la migration vers le nord du dcrochement actif senestre entre la Plaque nord-amricaine et la Plaque Carabe.
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Le concept de romanisation ne revt d'utilit que s'il peut tre qualifi, et donc analys en diffrents niveaux , afin de comparer les rythmes et les formes du phnomne dans les rgions de l'Empire. Avant mme de chercher tenir un discours global sur la romanisation, il faut donc en tudier les multiples aspects de manire spcifique. C'est dans ce cadre que s'inscrit cette thse de doctorat dont le but est de quantifier et de qualifier l'acculturation des cramiques fines en Gaule interne (200 BC - 50 AD). Fonde sur un corpus de quelques 130 ensembles, provenant de 21 sites urbains localiss entre le centre ouest de la France, l'Auvergne, le Plateau suisse et le Luxembourg, cette tude se caractrise par la mise en place de nouvelles approches mthodologiques, s'appuyant sur le calcul d'un indice de romanisation (quantifiant la romanisation d'un ensemble sur une chelle de 1 100) et sur l'analyse des modalits du phnomne. L'examen diachronique et cartographique des rsultats obtenus montrant de fortes disparits dans les processus d'acculturation des cramiques fines, des niveaux de romanisation ont pu tre dfinis, dont le principal intrt est d'ouvrir la comparaison avec les autres aspects de l'acculturation des Gaules (instrumentum culinaire, technique de construction, romanisation de l'anthroponymie...). The concept of Romanisation can only be considered useful if it can be qualified and analysed at different levels in order to compare the acculturation rates, frequency and form of the phenomenon among the regions in the Empire. But before an overview of Romanisation can be considered, its multiple aspects must be examined in a specific manner. Among the French speaking areas, it is only recently that research concerning Gaulish and Roman periods has risked expanding the scope to a supra regional scale. Against this background, the purpose of my doctoral thesis is to examine the qualitative and quantitative aspects of acculturation among Gaulish fine wares (200 BCE - 50 CE). Based on a corpus of 130 assemblages from 21 urban sites from the western centre of France, Auvergne, the Swiss plateau and Luxembourg, the study is characterised by new methodological techniques relying on the calculation of a 'Romanisation index' (quantifying the level of Romanisation of an assemblage on a scale of 1 to 100) and the analysis of the methods of the phenomenon. The diachronic and cartographic examination of the results obtained showed large disparities in the acculturation processes concerning fine wares. The level of Romanisation could be defined, thus allowing a comparison with other aspects of the acculturation process among other aspects of Gaulish culture such as tools, cuisine, construction techniques and Romanisation of anthroponyms.
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RESUME Les nombreuses mines de plomb et d'argent du Valais tmoignent d'une activit minire importante par le pass, sans toutefois dvoiler ni l'importance des minralisations, ni l'anciennet de l'exploitation. La prsente recherche a pour but de comprendre pourquoi les grandes mines sont concentres dans une rgion, et de dterminer la chronologie de leur exploitation. L'originalit de ce travail rside dans son interdisciplinarit, plus prcisment dans l'application des mthodes minralogiques pour rsoudre une problmatique historique. Afin d'valuer les ressources minires en plomb et en argent du Valais, 57 mines et indices ont t reprs et chantillonns. Les signatures isotopiques du Pb (74 analyses) et les compositions chimiques lmentaires (45 analyses) ont t dtermines. Les plus grandes exploitations se situent dans la nappe de Siviez-Mischabel, au Sud d'une ligne Valle du Rhne / Val de Bagnes ainsi que dans le Ltschental. Elles sont lies, d'aprs leur signature isotopique de plomb, des minralisations d'ge caldonien (408 387 Ma) ou tardi-hercynien (333 286 Ma). ces priodes, l'ancien continent est trs lourd et subit une subsidence thermique. Des premires fractures d'extrme importance se forment. Comme il s'agit d'accidents tectoniques majeurs, des gisements de grande extension peuvent se former dans ce contexte. D'autres minralisations se situent dans les domaines helvtiques (Massif des Aiguilles Rouges, Massif du Mont Blanc et couverture sdimentaire), couvrant une rgion au Nord de la Valle du Rhne et du Val d'Entremont. D'ge post-hercynien tardi-alpin (notons qu'il n'y a pas de minralisations d'ge tertiaire), elles sont pour la plupart lies des intrusions granitiques, sources de plomb juvnile. Les mines situes dans ces units tectoniques sont nettement moins tendues que celles de la nappe de Siviez-Mischabel, ce qui permet de penser que les minralisations correspondantes le sont galement. Les priodes d'exploitation des mines peuvent tre dtermines par quatre approches diffrentes l'archologie minire, la lecture des textes historiques, l'tude des dchets mtallurgiques et la comparaison de la signature isotopique du plomb, que l'on mesure dans un objet archologique bien dat (monnaie, bijoux etc.), avec celles des minerais. Cette dernire mthode a t applique et dveloppe dans le cadre de la prsente recherche. Pour ce faire, 221 chantillons d'objet en plomb ou en argent dats entre l'ge du Fer et le Moyen Age ont t analyss par la mthode des isotopes de plomb et compars environ 1800 signatures isotopiques de minerais des gisements les plus importants en Suisse et en Europe. Avant l'poque romaine et jusqu'au 1 er sicle de cette poque, le plomb provient principalement des mines de la pninsule ibrique alors en pleine activit. Un apport des mines d'Europe tempre, notamment des Vosges, reste confirmer. A partir du 1" sicle de notre re, le plomb a principalement t import en Suisse occidentale de grands centres de productions situes en Allemagne du Nord (rgion d'Eifel). Les mines de plomb valaisannes, notamment celles de Siviez, dbutent leur exploitation en mme temps, principalement pour couvrir les besoins locaux, mais galement pour l'exportation jusque dans l'arc lmanique et, dans une moindre importance, au-del. partir du 4me sicle, le besoin en plomb a t couvert par un apport des mines locales et par la refonte d'objets anciens. Ce changement d'approvisionnement est probablement li aux tensions cres par les invasions germaniques durant la seconde moiti du 3' sicle ; le march suisse n'est ds lors plus approvisionn par le nord, c'est--dire par la valle du Rhin. Quant l'argent, l'exploitation de ce mtal est atteste partir de la fin du La Tne, peu aprs l'apparition de ce mtal dans la rgion valaisanne. L'chantillonnage ne couvrant pas l'poque romaine, rien n'est connu pour cette priode. A partir du 5" sicle, une exploitation d'argent est de nouveau atteste. Cependant, l'exploitation d'argent des mines locales ne gagne en importance qu' partir du Moyen ge avec les frappes montaires, notamment les frappes carolingiennes et piscopales valaisannes. Les sources d'argent sont diffrentes selon leur utilisation : part quelques exceptions notamment vers la fin du La Tne et au tardo-antique, les bijoux et objets de cultes ont t souvent crs partir d'argent refondu, contrairement aux monnaies pour lesquelles l'argent provient des mines locales. On note un approvisionnement diffrent de ce mtal pour les objets, notamment les monnaies, selon leur lieu de fabrication : on peut clairement distinguer les objets valaisans de ceux du Plateau Suisse. SUMMARY The many lead and silver mines of the Valais testify of an important mining activity in the past, without however revealing neither the importance of the mineralizations, nor the era of the exploitation. The purpose of this research is to understand why the large mines are concentrated in one region, and to determine the history of their exploitation. The uniqueness of this work lies in its interdisciplinarity, more precisely in the application of mineralogical methods to solve historical problems. In order to evaluate the lead and silver mining resources of the Valais region, 57 mines and ore deposits were located and sampled. The isotope signatures of Pb (74 analyses) and the compositions of the chemical elements (45 analyses) were determined. The largest activities are in the Siviez-Mischabel area, located in the South of the boundary formed by the Rhone, Bagnes and Lotschental valleys. According to their lead isotope signatures, they are linked to mineralizations of the Caledonian (408 to 387 my) or tardi-Hercynian (333 to 286 my) orogenies. In those times, the old continent was very heavy and underwent a thermal subsidence. First fractures of great significance were formed. Through these major tectonic events, large extended ore deposits can be formed. Other mineralizations are found in the helvetic regions situated north of the Rhone and the Entremont valley (the Aiguilles Rouges basement, Mount Blanc basement and the covering sediment). Because they are from post-hercynien to tardi-alpine age (there are no mineralizations of tertiary age), they are mainly linked to granite intrusions, the sources of juvenile lead. The mines found in these tectonic units are significantly less extensive than those of the Siviez-Mischabel area, leading to the assumption that the respective mineralizations extend accordingly. The history of exploitation of the mines can be determined by four different sources: mining archaeology, historical texts, metallurgical waste, and the comparison of the isotope signature of the lead from accurately dated archaeological objects (currency, jewels etc), with those of the ores. This last approach was applied and developed within the framework of this research. The lead isotope signatures of 221 lead or silver objects from the Iron Age to the Middle Age were compared with approximately 1800 samples of ore of the most important ore deposits in Switzerland and Europe. Before the Roman time up to the 1st century, lead comes mainly from the mines of the Iberian Peninsula then in full activity. A contribution of the mines of Central Europe, in particular of the Vosges, remains to be confirmed. From the 1st century on, lead was mainly imported into Western Switzerland from Northern Germany (Eiffel region). The lead mines in the Valais region, in particular those of Siviez, begin their exploitation at the same time, mainly to meet the local needs, but also for export to the lemanic basin and of lesser importance, beyond. As from the 4th century, the need of lead was met by the production from local mines and the recycling of old objects. This change of supply is probably related to the tensions created by the Germanic invasions during second half of the 3rd century; as a consequence, the Swiss market is not supplied any more by the north, i.e. the Rhine valley. Silver production is confirmed starting from the end of La Tene, shortly after the appearance of this metal in the Valais region. Since no objects of Roman origin were analyzed, nothing is known for this period. From the 5th century on, silver production is again confirmed. However, significant silver production from local mines starts only in the Middle Age with the coinage, in particular Carolingian and Episcopal minting from the Valais region. The sources of silver differ according to their use: besides some exceptions in particular towards the end of La Tene and the tardi-Roman, the jewels and objects of worships were often created from recycled silver, contrary to the coins the silver for which comes from the local mines. A different source of silver is observed according to the location of coin manufacture: Objects originating from the Valais region are clearly distinguished from those from the Plateau Suisse. ZUSAMMENFASSUNG Die grosse Zahl von Blei- und Silberminen im Wallis ist Zeugnis einer bedeutenden Bergbauttigkeit, es fehlen aber Hinweise ber ihren Umfang und den Zeitraum ihrer Ausbeutung. Die vorliegende Arbeit sucht zu ergrnden, warum grosse Minen sich in einer eng begrenzten Region hufen und in welchem Zeitraum sie genutzt wurden. Die Besonderheit der Studie liegt in ihrer Interdisziplinaritt, genauer in der Anwendung von mineralogischen Methoden zur Beantwortung historischer Fragestellungen. Zur Beurteilung der Lagersttten wurden von 57 Minen und Aufschlssen Proben entnommen oder Nachweise erbracht und mittels 74 Isotopen-Analysen von Blei und 45 chemischen Gesamtanalysen ausgewertet. Die wichtigsten Vorkommen liegen in der Siviez- Mischabel- Decke sdlich der Linie Rhonetal- Val de Bagnes, sowie im Ltschental. Die Bleiisotopen- Alter weisen ihre Entstehung der kaledonischen (408 - 387 Mio. J.) oder der spt- herzynischen (333 - 286 Mio. J.) Gebirgsbildungsphase zu. In dieser Periode ist die kompakte Landmasse sehr schwer und erfairt eine thermische Absenkung. Es bilden sich tektonische Brche von kontinentaler Ausdehnung. Die grossen tektonischen Bewegungen ermglichen die Bildung von ausgedehnten Lagersttten. Andere Vorkommen finden sich im Bereich der Helvetischen Alpen (Aiguilles Rouges Massiv, Mont-Blanc-Massiv und Sediment-Decken) im Gebiet nrdlich des Rhonetales bis zum Val d'Entremont. Altersmssig sind sie der nach-hercynischen bis zur spt-alpidischen Orogenese zuzuweisen (auffllig ist das Fehlen von Vorkommen im Tertir) und haben sich meist in der Folge von Granit- Intrusion, dem Ursprung von primrem Blei ausgebildet. Die Bergwerke in diesem Bereich sind deutlich weniger ausgedehnt als jene in der Siviez-Mischabel-Decke und entsprechen wahrscheinlich dem geringen Umfang der zugehrigen Vorkommen. Die Nutzungsperioden der Minen knnen mit vier verschiedenen Methoden bestimmt werden: Minenarchologie, Historische Quellen, Auswertung von metallischen Abfllen (Schlacken) und Vergleich der Bleiisotopen-Zusammensetzung von Erzen mit jener von zeitlich gut datierbaren archologischen Gegenstnden (Mnzen, Schmuckstcke). Die letztere Methode wurde im Rahmen der vorliegenden Forschungsarbeit entwickelt und angewendet. Zu diesem Zweck wurden an 221 Proben von Blei- oder Silberobjekten, die in die Periode zwischen Eisenzeit und Mittelalter eingestuft werden knnen, Bleiisotopen- Analysen durchgefhrt und mit ca. 1800 Proben aus den wichtigsten Lagersttten der Schweiz und Europas verglichen. Vor der Rmerzeit und bis ins 1. Jahrh. stammt das Blei vornehmlich aus den in jener Zeit in voller Ausbeutung begriffenen Minen der Iberischen Halbinsel. Der Beitrag von Mitteleuropa, besonders der Vogesen, muss noch besttigt werden. Ab dem 1. Jahrh. nach Chr. wurde die Westschweiz hauptschlich mit Blei aus den grossen Produktionszentren Norddeutschlands, vorwiegend der Eifel, versorgt. In dieser Periode setzt die Ausbeutung der Bleiminen des Wallis, besonders von Siviez, ein. Sie dienen der Deckung des rtlichen Bedarfs aber auch der Ausfuhr in das Gebiet des Genfersees und in einem bescheidenen Rahmen sogar darber hinaus. Ab dem 4. Jahrhundert wurden vermehrt alte Objekte eingeschmolzen. Dieser Wechsel der Versorgungsquellen war vermutlich eine Folge der Wlkerwanderung in der zweiten Hlfte des 3. Jahrhunderts. Ab diesem Zeitpunkt war Helvetien der Zugang zu den Versorgungsquellen des Nordens, besonders des Rheinlandes, verwehrt. Der Abbau von Silber ist ab dem Ende des La Tne nachgewiesen, nur wenig nach dem Auftreten dieses Metalls im Wallis. ber die Rmerzeit knnen wegen dem Fehlen entsprechender Proben keine Aussagen gemacht werden. Eine erneute Abbauperiode ist ab dem 5. Jahrhundert nachgewiesen. Die Produktion der rtlichen Minen erreicht aber erst im Mittelalter eine gewisse Bedeutung mit der Prgung von Mnzen durch die Karolinger und die Walliser Bischfe. Die Herkunft des Silbers ist abhngig von dessen Verwendung. Mit wenigen Ausnahmen in der Zeit des La Tne und der spteren Rmerzeit wurde fr Kunst- und Kult- Gegenstnde rezykliertes Silber verwendet, fr Mnzprgungen neues Silber aus den rtlichen Minen. Von Einfluss auf die Herkunft war auch der Produktionsstandort: Die Objekte aus dem Wallis unterscheiden sich deutlich von jenen des Mittellandes.
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Benthic macroinvertebrate assemblages do not appear to differ as markedly between coldwater and warmwater streams (in Iowa, at least) as do fish assemblages, and to our knowledge no parallel evaluation of benthic macroinvertebrate communities in coldwater streams has been conducted. What is known is that many taxa are exclusively collected in coldwater environments and are considered rare in Iowa from a biogeographical perspective. While the warmwater BMIBI has generally proven to work well as a diagnostic tool for Iowas streams, the streams of Iowas Paleozoic Plateau tend to group in the excellent to good qualitative rating categories. The streams of this area tend to be more ecologically intact than other areas of the state; however, there are some artifacts of the current warmwater BMIBI (most specifically metric scoring related to watershed size) that skew IBI values higher. Our objective is to develop a Coldwater Benthic Index (CBI) which will provide a more accurate assessment of streams classified, or potentially classifiable, as coldwater.
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PURPOSE: To evaluate the safety and potential use of poly(lactic) acid (PLA) and poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) as vectors for gene transfer to RPE cells. METHODS: Experiments were conducted with primary bovine RPE cells and with the ARPE-19 human RPE cell line. Rhodamine loaded NPs were used to study factors influencing the internalization process by the various RPE cells: concentrations of NPs, duration of contact time, stage of cell culture and ambient temperature. The extent of NPs internalization was evaluated by fluorescence and phase microscopy. Potential NP toxicity was measured by the trypan blue exclusion dye test and the MTT method. Green fluorescent protein (GFP) plasmid or red nuclear fluorescent protein (RNFP) plasmid were sequestered in NPs. The ability ot these "loaded" NPs to generate gene transfection and protein expression in RPE cells was assessed both in vivo and in vitro by fluorescence and confocal microscopy. RESULTS: The extent of NP internalization in cultured cells increases with their concentration reaching a plateau at 1 mg/ml and a contact time of up to 6 h. Temperature and culture stage did not influence the in vitro internalization process. No toxic effects on RPE cells could be detected when these were incubated with up to 4 mg/ml of NPs. In human and bovine RPE cells incubated with GFP loaded NPs, cytoplasmic green fluorescence was observed in 14+/-1.65% of the cultured cells. Incubation with RNFP loaded NPs yielded a nuclear red fluorescence in 18.9+/-1.6% of the cells. These percentage levels of expression initially detected after 48 h of incubation remained unchanged during the following 8 additional days in culture. No significant differences in the extent of cytoplasm or nuclear fluorescence expression were observed between bovine or human RPE cultured cells. In vivo, a preferential RNFP expression within the RPE cell layer was detected after intra vitreous injection of RNFP plasmid loaded NPs. CONCLUSIONS: The ability of PLGA NPs to sequester plasmids, their nontoxic characteristics, and rapid internalization enables gene transfer and expression in RPE cells. These findings may be of potential use when designing future gene therapy strategies for ocular diseases of the posterior segment.
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The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization (oilseed radish); and natural vegetation, without grazing and nitrogen fertilization (fallow). Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.
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The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerrado stricto sensu" and "campo sujo"), under different fire regimes, and a 20-year-old active palisadegrass pasture in the Central Plateau of Brazil. Microbial biomass was higher in the native plots than in the pasture, and the highest monthly values were observed during the rainy season in the native plots. No significant differences were observed between fire regimes or between communities from the two native vegetation types. However, the principal component (PC) analysis separated the microbial communities by vegetation cover (native x pasture) and season (wet x dry), accounting for 45.8% (PC1 and PC3) and 25.6% (PC2 and PC3), respectively, of the total PLFA variability. Changes in land cover and seasonal rainfall in Cerrado ecosystems have significant effects on the total density of soil microorganisms and on the abundance of microbial groups, especially Gram-negative and Gram-positive bacteria.
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PURPOSE: Reconstruction of the posterior cruciate ligament (PCL) yields less satisfying results than anterior cruciate ligament reconstruction with respect to laxity control. Accurate tibial tunnel placement is crucial for successful PCL reconstruction using arthroscopic tibial tunnel techniques. A discrepancy between anatomical studies of the tibial PCL insertion site and surgical recommendations for tibial tunnel placement remains. The objective of this study was to identify the optimal placement of the tibial tunnel in PCL reconstruction based on clinical studies. METHODS: In a systematic review of the literature, MEDLINE, EMBASE, Cochrane Review, and Cochrane Central Register of Controlled Trials were screened for articles about PCL reconstruction from January 1990 to September 2011. Clinical trials comparing at least two PCL reconstruction techniques were extracted and independently analysed by each author. Only studies comparing different tibial tunnel placements in the retrospinal area were included. RESULTS: This systematic review found no comparative clinical trial for tibial tunnel placement in PCL reconstruction. Several anatomical, radiological, and biomechanical studies have described the tibial insertion sites of the native PCL and have led to recommendations for placement of the tibial tunnel outlet in the retrospinal area. However, surgical recommendations and the results of morphological studies are often contradictory. CONCLUSIONS: Reliable anatomical landmarks for tunnel placement are lacking. Future randomized controlled trials could compare precisely defined tibial tunnel placements in PCL reconstruction, which would require an established mapping of the retrospinal area of the tibial plateau with defined anatomical and radiological landmarks.
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OBJECTIVE: This study was undertaken to investigate how aging affects dermal microvascular reactivity in skin areas differentially exposed to sunlight, and therefore to different degrees of photoaging. METHODS: We assessed, in young (18-30years, n=13) and aged males (≥60years, n=13), the thigh, forearm, and forehead's skin vasodilatory response to local heating (LTH) with a LDI. In each subject and at each location, local Tskin was brought from 34C (baseline) to 39 or 41C for 30minutes, to effect submaximal vasodilation, with maximal vasodilation then elicited by further heating to 44C. RESULTS: The CVCs evaluated at baseline and after maximal vasodilation (CVCmax ) were higher in the forehead than in the two other anatomical locations. On all locations, CVCmax decreased with age but less markedly in the forehead compared to the two other locations. When expressed in % of CVCmax , the plateau increase of CVCs in response to submaximal temperatures (39 and 41C) did not vary with age, and minimally so with location. CONCLUSION: Skin aging, whether intrinsic or combined with photoaging, reduces the maximal vasodilatory capacity of the dermal microcirculation, but not its reactivity to local heating.
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One signature of adaptive radiation is a high level of trait change early during the diversification process and a plateau toward the end of the radiation. Although the study of the tempo of evolution has historically been the domain of paleontologists, recently developed phylogenetic tools allow for the rigorous examination of trait evolution in a tremendous diversity of organisms. Enemy-driven adaptive radiation was a key prediction of Ehrlich and Raven's coevolutionary hypothesis [Ehrlich PR, Raven PH (1964) Evolution 18:586-608], yet has remained largely untested. Here we examine patterns of trait evolution in 51 North American milkweed species (Asclepias), using maximum likelihood methods. We study 7 traits of the milkweeds, ranging from seed size and foliar physiological traits to defense traits (cardenolides, latex, and trichomes) previously shown to impact herbivores, including the monarch butterfly. We compare the fit of simple random-walk models of trait evolution to models that incorporate stabilizing selection (Ornstein-Ulenbeck process), as well as time-varying rates of trait evolution. Early bursts of trait evolution were implicated for 2 traits, while stabilizing selection was implicated for several others. We further modeled the relationship between trait change and species diversification while allowing rates of trait evolution to vary during the radiation. Species-rich lineages underwent a proportionately greater decline in latex and cardenolides relative to species-poor lineages, and the rate of trait change was most rapid early in the radiation. An interpretation of this result is that reduced investment in defensive traits accelerated diversification, and disproportionately so, early in the adaptive radiation of milkweeds.
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BACKGROUND AND AIMS: Black cherry (Prunus serotina) is a North American tree that is rapidly invading European forests. This species was introduced first as an ornamental plant, then it was massively planted by foresters in many countries, but its origins and the process of invasion remain poorly documented. Based on a genetic survey of both native and invasive ranges, the invasion history of black cherry was investigated by identifying putative source populations and then assessing the importance of multiple introductions on the maintenance of gene diversity. METHODS: Genetic variability and structure of 23 populations from the invasive range and 22 populations from the native range were analysed using eight nuclear microsatellite loci and five chloroplast DNA regions. KEY RESULTS: Chloroplast DNA diversity suggests there were multiple introductions from a single geographic region (the north-eastern United States). A low reduction of genetic diversity was observed in the invasive range for both nuclear and plastid genomes. High propagule pressure including both the size and number of introductions shaped the genetic structure in Europe and boosted genetic diversity. Populations from Denmark, The Netherlands, Belgium and Germany showed high genetic diversity and low differentiation among populations, supporting the hypothesis that numerous introduction events, including multiple individuals and exchanges between sites, have taken place during two centuries of plantation. CONCLUSIONS: This study postulates that the invasive black cherry has originated from east of the Appalachian Mountains (mainly the Allegheny plateau) and its invasiveness in north-western Europe is mainly due to multiple introductions containing high numbers of individuals.
