948 resultados para CARBONATE PLATFORM
Resumo:
North Amerlc8 W8S inundated by fJ major eplcontlnental sea during ihe C:retaceo.us Period. The sOljihw6rd transgression of th.e northern Boreal See along the ~\festern Interior Seaway resulted in a meetlng with the northward edv6nclng waters from the GUlf of Mexico (Obradovich and Cobban, 1975). Th1s link was 1n eXlstence by late Albien time and 6llowed for the comm1ngl1ng of the prol1ferous Arctic and Gulf rnar1ne faunas (F1g. 1). By early Campanlan time, there was a widening of B6ffln Bay wlth a slrnult8neous subsidence 1n the Arct1c Archlpelago and Sverdrup 6as1n (W11liam and Stelck, 1975). Williams and Burk (1964) found 6 break 1n the marines sedlmentatlon in the f1anltoba area, suggesting Bland corlnectlon from the Dlstrlct of Keewatln through eastern M6fl1toba to the lake Sl~perlor reglon, lmplying that the only dlrect connection between the Interlor Sea with Baffln Bay, was yia the Arct1c. This hiatus was also documented by Meek and Hayden (1861) ln the United states between the Niobrara and Pierre Format1ons. Jeletzky (1971) suggested that the retreat of the sea towards the east was by a serles of strong pulses resultlng in the regression of the Campanlan and M66str1chtlan seas. During ttle Cretaceous1 the r1s1ng Corl1111era caused the western shoreline of the Interlor Sea to migrate eastwards and the Cordillera'l detritus produced deltaic cornplexes from the Mackenzie Valley to Ne\N Mexlcoo The foreland basin was continually subslding and thls down\",arplng aided in the eastward m1gration of the western shorel1ne. Thls also lndicates that trle water 'tIes becom1ng deeper in the central Plains sect10n of the Seaway (Fig. 2).
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A big challenge associated with getting an institutional repository off the ground is getting content into it. This article will look at how to use digitization services at the Internet Archive alongside software utilities that the author developed to automate the harvesting of scanned dissertations and associated Dublin Core XML files to create an ETD Portal using the DSpace platform. The end result is a metadata-rich, full-text collection of theses that can be constructed for little out of pocket cost.
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Un papier bioactif est obtenu par la modification d’un papier en y immobilisant une ou plusieurs biomolécules. La recherche et le développement de papiers bioactifs est en plein essor car le papier est un substrat peu dispendieux qui est déjà d’usage très répandu à travers le monde. Bien que les papiers bioactifs n’aient pas connus de succès commercial depuis la mise en marche de bandelettes mesurant le taux de glucose dans les années cinquante, de nombreux groupes de recherche travaillent à immobiliser des biomolécules sur le papier pour obtenir un papier bioactif qui est abordable et possède une bonne durée de vie. Contrairement à la glucose oxidase, l’enzyme utilisée sur ces bandelettes, la majorité des biomolécules sont très fragiles et perdent leur activité très rapidement lorsqu’immobilisées sur des papiers. Le développement de nouveaux papiers bioactifs pouvant détecter des substances d’intérêt ou même désactiver des pathogènes dépend donc de découverte de nouvelles techniques d’immobilisation des biomolécules permettant de maintenir leur activité tout en étant applicable dans la chaîne de production actuelle des papiers fins. Le but de cette thèse est de développer une technique d’immobilisation efficace et versatile, permettant de protéger l’activité de biomolécules incorporées sur des papiers. La microencapsulation a été choisie comme technique d’immobilisation car elle permet d’enfermer de grandes quantités de biomolécules à l’intérieur d’une sphère poreuse permettant leur protection. Pour cette étude, le polymère poly(éthylènediimine) a été choisi afin de générer la paroi des microcapsules. Les enzymes laccase et glucose oxidase, dont les propriétés sont bien établies, seront utilisées comme biomolécules test. Dans un premier temps, deux procédures d’encapsulation ont été développées puis étudiées. La méthode par émulsion produit des microcapsules de plus petits diamètres que la méthode par encapsulation utilisant un encapsulateur, bien que cette dernière offre une meilleure efficacité d’encapsulation. Par la suite, l’effet de la procédure d’encapsulation sur l’activité enzymatique et la stabilité thermique des enzymes a été étudié à cause de l’importance du maintien de l’activité sur le développement d’une plateforme d’immobilisation. L’effet de la nature du polymère utilisé pour la fabrication des capsules sur la conformation de l’enzyme a été étudié pour la première fois. Finalement, l’applicabilité des microcapsules de poly(éthylèneimine) dans la confection de papiers bioactifs a été démontré par le biais de trois prototypes. Un papier réagissant au glucose a été obtenu en immobilisant des microcapsules contenant l’enzyme glucose oxidase. Un papier sensible à l’enzyme neuraminidase pour la détection de la vaginose bactérienne avec une plus grande stabilité durant l’entreposage a été fait en encapsulant les réactifs colorimétriques dans des capsules de poly(éthylèneimine). L’utilisation de microcapsules pour l’immobilisation d’anticorps a également été étudiée. Les avancées au niveau de la plateforme d’immobilisation de biomolécules par microencapsulation qui ont été réalisées lors de cette thèse permettront de mieux comprendre l’effet des réactifs impliqués dans la procédure de microencapsulation sur la stabilité, l’activité et la conformation des biomolécules. Les résultats obtenus démontrent que la plateforme d’immobilisation développée peut être appliquée pour la confection de nouveaux papiers bioactifs.
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We developed a nanoparticles (NPs) library from poly(ethylene glycol)–poly lactic acid comb-like polymers with variable amount of PEG. Curcumin was encapsulated in the NPs with a view to develop a delivery platform to treat diseases involving oxidative stress affecting the CNS. We observed a sharp decrease in size between 15 and 20% w/w of PEG which corresponds to a transition from a large solid particle structure to a “micelle-like” or “polymer nano-aggregate” structure. Drug loading, loading efficacy and release kinetics were determined. The diffusion coefficients of curcumin in NPs were determined using a mathematical modeling. The higher diffusion was observed for solid particles compared to “polymer nano-aggregate” particles. NPs did not present any significant toxicity when tested in vitro on a neuronal cell line. Moreover, the ability of NPs carrying curcumin to prevent oxidative stress was evidenced and linked to polymer architecture and NPs organization. Our study showed the intimate relationship between the polymer architecture and the biophysical properties of the resulting NPs and sheds light on new approaches to design efficient NP-based drug carriers.
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The catalyst compositions of the Zn1−xCOxFe2O4 (x= 0, 0.2, 0.5, 0.8 and 1.0) spiel series possessing ‘x’ values, x less than or equal to 0.5, are unique for selective N-monomethylation of aniline using methanol as the alkylating agent. Since dimethyl carbonate (DMC) is another potential non-toxic alkylating agent, alkylation of aniline was investigated over various Zn–Co ferrites using DMC as the alkylating agent. The merits and demerits of the two alkylating agents are compared. Catalytic activity followed a similar trend with respect to the composition of the ferrospinel systems. DMC is active at comparatively low temperature, where methanol shows only mild activity. However, on the selectivity basis, DMC as an alkylating agent could not compete with methanol, since the former gave appreciable amounts of N,N-dimethylaniline (NNDMA) even at low temperature where methanol gave nearly 99% N-methylaniline (NMA) selectivity. As in the case of methanol, DMC also did not give any C-alkylated products.
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Shrimp cell lines are yet to be reported and this restricts the prospects of investigating the associated viral pathogens, especially white spot syndrome virus (WSSV). In this context, development of primary cell cultures from lymphoid organs was standardized. Poly-l-lysine-coated culture vessels enhanced growth of lymphoid cells, while the application of vertebrate growth factors did not, except insulin-like growth factor-1 (IGF-1). Susceptibility of the lymphoid cells to WSSV was confirmed by immunofluoresence assay using monoclonal antibody against the 28 kDa envelope protein of WSSV. Expression of viral and immunerelated genes in WSSV-infected lymphoid cultures could be demonstrated by RT-PCR. This emphasizes the utility of lymphoid primary cell culture as a platform for research in virus–cell interaction, virus morphogenesis, up and downregulation of shrimp immune-related genes, and also for the discovery of novel drugs to combat WSSV in shrimp culture
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• Premise of the study: Microsatellite markers were developed in Fosterella christophii (Bromeliaceae) to investigate the genetic diversity and population structure within the F. micrantha group, comprising F. christophii, F. micrantha, and F. villosula. • Methods and Results: Full-length cDNAs were isolated from F. christophii and sequenced on a Pacific Biosciences RS platform. A total of 1590 high-quality consensus isoforms were assembled into 971 unigenes containing 421 perfect microsatellites. Thirty primer sets were designed, of which 13 revealed a high level of polymorphism in three populations of F. christophii, with four to nine alleles per locus. Each of these 13 loci cross-amplified in the closely related species F. micrantha and F. villosula, with one to six and one to 11 alleles per locus, respectively. • Conclusions: The new markers are promising tools to study the population genetics of F. christophii and to discover species boundaries within the F. micrantha group.
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Hypermedia systems based on the Web for open distance education are becoming increasingly popular as tools for user-driven access learning information. Adaptive hypermedia is a new direction in research within the area of user-adaptive systems, to increase its functionality by making it personalized [Eklu 961. This paper sketches a general agents architecture to include navigational adaptability and user-friendly processes which would guide and accompany the student during hislher learning on the PLAN-G hypermedia system (New Generation Telematics Platform to Support Open and Distance Learning), with the aid of computer networks and specifically WWW technology [Marz 98-1] [Marz 98-2]. The PLAN-G actual prototype is successfully used with some informatics courses (the current version has no agents yet). The propased multi-agent system, contains two different types of adaptive autonomous software agents: Personal Digital Agents {Interface), to interacl directly with the student when necessary; and Information Agents (Intermediaries), to filtrate and discover information to learn and to adapt navigation space to a specific student
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This research work deals with the problem of modeling and design of low level speed controller for the mobile robot PRIM. The main objective is to develop an effective educational tool. On one hand, the interests in using the open mobile platform PRIM consist in integrating several highly related subjects to the automatic control theory in an educational context, by embracing the subjects of communications, signal processing, sensor fusion and hardware design, amongst others. On the other hand, the idea is to implement useful navigation strategies such that the robot can be served as a mobile multimedia information point. It is in this context, when navigation strategies are oriented to goal achievement, that a local model predictive control is attained. Hence, such studies are presented as a very interesting control strategy in order to develop the future capabilities of the system
Resumo:
This paper is focused on the robot mobile platform PRIM (platform robot information multimedia). This robot has been made in order to cover two main needs of our group, on one hand the need for a full open mobile robotic platform that is very useful in fulfilling the teaching and research activity of our school community, and on the other hand with the idea of introducing an ethical product which would be useful as mobile multimedia information point as a service tool. This paper introduces exactly how the system is made up and explains just what the philosophy is behind this work. The navigation strategies and sensor fusion, where machine vision system is the most important one, are oriented towards goal achievement and are the key to the behaviour of the robot
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The ongoing reforms, which were introduced under the Bologna Process and have already been extended outside of Europe , are a unique opportunity for reinforcing and structuring a common platform of understanding among members, based on the full time undergraduate courses in ( Urbanismo) Urban and Regional Planning. The training programs at this 1st cycle level, will obviously continue with the 2nd and 3rd cycles (Bachelor's Degree, Master's Degree and PhD Degree or 3+2+3 years). The training programs at this full time 1st cycle level, can also becomes the framework of understanding for the development of research in the urban fields at national and international levels.
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Aerosols from anthropogenic and natural sources have been recognized as having an important impact on the climate system. However, the small size of aerosol particles (ranging from 0.01 to more than 10 μm in diameter) and their influence on solar and terrestrial radiation makes them difficult to represent within the coarse resolution of general circulation models (GCMs) such that small-scale processes, for example, sulfate formation and conversion, need parameterizing. It is the parameterization of emissions, conversion, and deposition and the radiative effects of aerosol particles that causes uncertainty in their representation within GCMs. The aim of this study was to perturb aspects of a sulfur cycle scheme used within a GCM to represent the climatological impacts of sulfate aerosol derived from natural and anthropogenic sulfur sources. It was found that perturbing volcanic SO2 emissions and the scavenging rate of SO2 by precipitation had the largest influence on the sulfate burden. When these parameters were perturbed the sulfate burden ranged from 0.73 to 1.17 TgS for 2050 sulfur emissions (A2 Special Report on Emissions Scenarios (SRES)), comparable with the range in sulfate burden across all the Intergovernmental Panel on Climate Change SRESs. Thus, the results here suggest that the range in sulfate burden due to model uncertainty is comparable with scenario uncertainty. Despite the large range in sulfate burden there was little influence on the climate sensitivity, which had a range of less than 0.5 K across the ensemble. We hypothesize that this small effect was partly associated with high sulfate loadings in the control phase of the experiment.
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Increasing levels of CO2 and H+ proton in the rhizosphere from some legumes may play an important role in calcite dissolution of calcareous salt affected soils. Soils planted with white and brown varieties of cowpea (Vigna unguiculata L.) and hyacinth bean (Dolichos lablab L.) relying on either fertilizer N (KNO3) or N-fixation were compared against soils to which gypsum was applied and a control without plants and gypsum application to study the possibility of Ca2+ release from calcite and Na+ leaching. As compared to plants relying on inorganic N, leachates from all pore volumes (0·5, 1·0, 1·5, 2·0 pore volume) in lysimeters planted with N-fixing hyacinth bean contained significantly higher concentrations of HCO with lower concentrations from lysimeters planted with white cowpea relying on N-fixation. However, the lowest concentrations of HCO were recorded in the gypsum and control treatments. In initial leaching, lysimeters planted with N-fixing plants maintained similar leachate Ca2+ and Na+ concentrations compared to gypsum amended soils. However, gypsum amended soils were found to have a prolonged positive effect on Na+ removal. It might be concluded that some legumes that are known to fix N in calcareous salt affected soils may be an alternative ameliorant to the extremely expensive gypsum through calcite solubilization and a consequent release of Ca2+.