Les thiols et le sélénium peuvent jouer un rôle important dans la méthylation du mercure des environnements aquatiques. Pour démontrer la présence des thiols et du sélénium et leur relation avec le mercure dans certains écosystèmes d'eau douce québécois, une campagne d’échantillonnage fut réalisée durant l’été 2010, dans le parc national du Mont-Tremblant (Laurentides, Québec). Il existe une corrélation significative entre le sélénium et le mercure total dans l’eau des lacs du parc. Cependant, les concentrations de sélénium sont très faibles dans les lacs, les étangs de castor et les ruisseaux. Par ailleurs, les lacs du parc national du Mont-Tremblant ont des concentrations relativement élevées de méthylmercure avec une moyenne de 0,33 ng L-1 et des maximums allant jusqu’à 3,29 ng L-1. Les étangs de castor peuvent aussi être considérés comme des lieux de contamination au méthylmercure, avec une concentration moyenne de 0,95 ng L-1. Toutefois, la présence d’une colonie de castors sur le bassin versant d’un lac ne semble pas influencer les concentrations de mercure que l’on y retrouve. Deux thiols sont détectables dans l’eau de surface des Laurentides, soit le glutathion et l’acide thioglycolique. La concentration de ce dernier thiol est corrélée significativement avec celle du mercure total et du méthylmercure. Les thiols peuvent jouer un rôle important dans les processus de méthylation en favorisant le transport du mercure inorganique à l’intérieur des bactéries sulfato-réductrices. Afin de mieux comprendre l’action antagoniste entre le sélénium et le mercure, des études devraient être réalisées au niveau des tissus des organismes vivants dans ces zones pauvres en sélénium. / Thiols and selenium may influence mercury methylation in aquatic environments. To demonstrate the occurrence of both elements with mercury in selected aquatic systems of Quebec, a sampling campaign was conducted during the summer of 2010 in Mont-Temblant national park (Laurentians, Quebec). There is a significant correlation between selenium and total mercury in surface water. However, concentrations of selenium are very low in lakes and beavers ponds. In addition, the park’s lakes have a relatively high concentrations of methyl mercury with an average of 0,33 ng L-1 and maximum values up to 3,29 ng L-1. Beaver ponds can also be considered hotspots of methylmercury contamination, with an average concentration of 0,95 ng L-1. However, the presence of a colony of beavers in the watershed of a lake does not appear to influence the levels of mercury in that lake. Two species of thiols are present in the surface water of the Laurentian ecosystems: glutathione and thioglycolic acid. The latter is significantly correlated with total mercury and methyl mercury. Thiols may play an important role in the methylation process by promoting the transport of inorganic mercury within the sulfate-reducing bacteria. To better undestand the antagonistic action between selenium and mercury, more research should be conducted in the tissue of organisms living in areas of low concentration of selenium to know if they are protected against mercury toxicity.

Šio darbo tikslas buvo ištirti atsitiktinai padaugintos polimorfinės DNR (APPD) metodu skirtingas Europinio bebro (Castor fiber) subpopuliacijas Lietuvoje. Buvo ištirtos Europinio bebro 4 subpopuliacijose: Mituvos, Vilkaraisčio, Giedraičių ir Rusnės salos. DNR atsitiktinai padaugintų fragmentų polimorfizmas buvo tirtas naudojant 10 pradmenų. Pagal Nei apskaičuotą genetinę distanciją tarp populiacijų, labiausiai genetiškai panašios buvo Giedraičių ir Vilkraisčio subpopuliacijos (0,936), didžiausia genetinė distancija nustatyta tarp Rusnės salos ir Vilkaraisčio subpopuliacijų (0,288). Ištirtos subpopuliacijos grupuojasi į du klasterius: vieną klasterį sudaro Rusnės salos ir Mituvos subpopuliacijos, kitą – Vilkaraisčio ir Giedraičių subpopuliacijos. Europinio bebro subpopuliacijų genetinei įvairovei nustatyti, Popgene programa buvo apskaičiuoti 4 parametrai. Shannon informacinis indeksas svyravo nuo 0,2527 (Rusnės sala) iki 0,3895 (Giedraičiai). Nei genetinė įvairovė svyravo nuo 0,1677 (Rusnės sala) iki 0,2589 (Mituva). Didžiausias nustatytas alelių skaičius buvo Mituvoje (1,8911), mažiausias Rusnės saloje (1,5050). Efektyvus alelių skaičius svyravo nuo 1,2864 (Rusnės sala) iki 1,444 (Giedraičiai). Didžiausia genetinė įvairovė buvo aptikta Mituvos subpopuliacijoje, o mažiausia genetine įvairove pasižymi Rusnės salos subpopuliacija. Daugiausia polimorfinių lokusų buvo aptikta Mituvos subpopuliacijoje (89,11%), o mažiausiai Rusnės salos subpopuliacijoje (50,5%). Nustatėmė, kad... [toliau žr. visą tekstą] / The aim of this study is to evaluate genetic structure of European beavers (Castor fiber) subpopulations from Lithuania using RAPD (Random Amplified Polymorphic DNA) method. We investigated genetic variability of 4 subpopulations from Rusne, Mituva, Giedraiciai and Vilkaraistis. 10 primers were used in this analysis. Acording to Nei‘s genetic identity, the most similar were subpopulations from Giedraiciai and Vilkaraistis (0,936), the highest genetic distance was observed between subpopulations from Rusnes island and Vilkaraistis (0,288). These subpopulations form two clusters: Mituva and Rusnes island forms one cluster and Vilkaraistis and Giedraiciai – another. To evaluate the genetic variation in subpopulations we analysed four parameters. Shannon’s informations index was from 0,2527 in Rusnes island to 0,3895 in Giedraiciai.The highest Nei‘s genetic variaty was observed in subpopulation from Mituva and the smallest in Rusnes island (0,1677).The highest number of alleles was detected in Mituva (1,8911) and the smalest in Rusnes island (1,5050). The efective number of alleles was from 1,2864 in Rusnes island to 1,444 in Giedraiciai. From these parametres we can see that the most genetic diversity is observed in subpopulation from Mituva and the smallest in subpopulation from Rusnes island. We detected that the in Rusnes island 50,5 % of loci were polimorphic, and in subpopulation from Mituva even 89,11% of loci were polimorphic. We found out that molecular diversity is... [to full text]

Les thiols et le sélénium peuvent jouer un rôle important dans la méthylation du mercure des environnements aquatiques. Pour démontrer la présence des thiols et du sélénium et leur relation avec le mercure dans certains écosystèmes d'eau douce québécois, une campagne d’échantillonnage fut réalisée durant l’été 2010, dans le parc national du Mont-Tremblant (Laurentides, Québec). Il existe une corrélation significative entre le sélénium et le mercure total dans l’eau des lacs du parc. Cependant, les concentrations de sélénium sont très faibles dans les lacs, les étangs de castor et les ruisseaux. Par ailleurs, les lacs du parc national du Mont-Tremblant ont des concentrations relativement élevées de méthylmercure avec une moyenne de 0,33 ng L-1 et des maximums allant jusqu’à 3,29 ng L-1. Les étangs de castor peuvent aussi être considérés comme des lieux de contamination au méthylmercure, avec une concentration moyenne de 0,95 ng L-1. Toutefois, la présence d’une colonie de castors sur le bassin versant d’un lac ne semble pas influencer les concentrations de mercure que l’on y retrouve. Deux thiols sont détectables dans l’eau de surface des Laurentides, soit le glutathion et l’acide thioglycolique. La concentration de ce dernier thiol est corrélée significativement avec celle du mercure total et du méthylmercure. Les thiols peuvent jouer un rôle important dans les processus de méthylation en favorisant le transport du mercure inorganique à l’intérieur des bactéries sulfato-réductrices. Afin de mieux comprendre l’action antagoniste entre le sélénium et le mercure, des études devraient être réalisées au niveau des tissus des organismes vivants dans ces zones pauvres en sélénium. / Thiols and selenium may influence mercury methylation in aquatic environments. To demonstrate the occurrence of both elements with mercury in selected aquatic systems of Quebec, a sampling campaign was conducted during the summer of 2010 in Mont-Temblant national park (Laurentians, Quebec). There is a significant correlation between selenium and total mercury in surface water. However, concentrations of selenium are very low in lakes and beavers ponds. In addition, the park’s lakes have a relatively high concentrations of methyl mercury with an average of 0,33 ng L-1 and maximum values up to 3,29 ng L-1. Beaver ponds can also be considered hotspots of methylmercury contamination, with an average concentration of 0,95 ng L-1. However, the presence of a colony of beavers in the watershed of a lake does not appear to influence the levels of mercury in that lake. Two species of thiols are present in the surface water of the Laurentian ecosystems: glutathione and thioglycolic acid. The latter is significantly correlated with total mercury and methyl mercury. Thiols may play an important role in the methylation process by promoting the transport of inorganic mercury within the sulfate-reducing bacteria. To better undestand the antagonistic action between selenium and mercury, more research should be conducted in the tissue of organisms living in areas of low concentration of selenium to know if they are protected against mercury toxicity.

Includes bibliographical references (leaves 83-96). / Thesis (D. Min.)--Trinity Episcopal School for Ministry, 2008.

Precambrian metamorphic rocks in the Beaver Dam Mountains display asymmetric, isoclinal folds with consistent fold axes plunging to the NW. These folds are parasitic and have a recursive nature that occurs on wavelengths from centimeters to perhaps kilometers as part of a NW-SE striking shear zone. The vergence of the folds indicates oblique shearing with a transport direction plunging 29° to the south. This shear zone may be associated with the collision of Yavapai Province island arcs with Laurentia. Structurally overlying, and adjacent to the metamorphic rocks are allochthonous and attenuated Mississippian limestone blocks and other strata debated to be either the result of mega-landsliding or fragments of the hanging wall rocks above a low-angle normal fault. We document previously unreported cataclastic damage zones tens of meters thick, an anastomosing zone of greenschist facies alteration hundreds of meters thick, and polished low-angle fault surfaces beneath these blocks. Other observations previously used to support a mega-landslide hypothesis are blocks of Redwall Limestone structurally overlying what was interpreted as Tertiary conglomerate. However, this contact is depositional, and the conglomerate is likely a sedimentary breccia facies of the Mississippian Redwall Limestone which is documented in several locations within the region. Additionally, some of the deformation and attenuation that was wrongly attributed to mega-landsliding or low-angle normal faulting is due to previously undocumented soft-sediment deformation. This deformation was gravity driven and accommodated by ductile granular flow, resulting in recumbent folds within the Mississippian Redwall Limestone and a prominent non-brittle detachment surface between the Redwall Limestone and the Cambrian Bonanza King Formation at Castle Cliff. This detachment was previously interpreted as the Castle Cliff Detachment, a low-angle normal fault, or as the slip surface of a landslide.

I studied movement characteristics and vegetative resources effects on home range size of beavers at Redstone Arsenal (RSA) in north central Alabama, USA. Beavers were captured and radio tagged from 11 wetlands during winter and spring of 2011. I monitored movements of radio-tagged beavers using radio telemetry from May 2011–April 2012. Beavers moved faster, presumably more favorable to central place foraging, in wetland as they proceeded farther away from the central place, but did not in upland. Additionally, distributions of hourly distances from lodges were bimodal. Home range, core areas, and distance from lodge did not differ between age classes. Home range sizes increased with increasing habitat productivity and resource dispersion, whereas home ranges decreased with temporal variation in resources throughout the year. Quantity and spatial distribution of resources and patterns of foraging behavior influence movements and home ranges of central place foragers.

<p dir="ltr">North American beaver are ecosystem and habitat altering mammals with a wide distribution in North America. Beaver are associated with bodies of fresh water while utilizing riparian habitat by foraging on woody and herbaceous, terrestrial and aquatic vegetation, as well as creating lodges, dams, dens, and scent mounds. Chain O’Lakes State Park was chosen as a study area for surveying beaver activity and woody species communities. The aim of the study was to better understand the relationship between beaver, and specifically, the woody vegetation in their foraging and home range. There is a large swath of habitat that beaver can utilize and alter within Chain O’Lakes State Park including the lakes, streams, and forests that attract visitors. The factors that have been found to influence beaver utilization in Chain O’Lakes State Park (and North America at large) are woody species community composition, abundance of heavily preferred woody species, as well as a combination of both an absence of predators and an abundance of aquatic vegetation. Based on the distribution of heavily, occasionally, and rarely preferred woody species across the understory (new individuals) and overstory (mature individuals) stratum an inference can be made that most of the riparian habitat around the lakes will continue to and/or shift into a higher proportion of species that beaver heavily select. A minority of the habitat shall shift away from those species and towards rarely and/or occasionally selected species. I will provide USDA APHIS Wildlife Services that play a wildlife management role in Chain O’Lakes State Park with the survey information detailing how beaver and their structures interact with the ecosystem, hypothesized methods for preserving the woody species that are targeted by beaver foraging within the park, and supplementary information that may aid in maintaining the riparian habitats for the benefit of park’s biodiversity and wildlife persistence while continuing to provide an enriched experience within Northwest Indiana with the potential to inform the greater collection of parks and maintained land at large.</p>

No description available.

Ce mémoire présente une analyse tracéologique, c’est-à-dire l’analyse fonctionnelle d’un objet à partir des microtraces d’usure, appliquée à une collection d’incisives de castor issue des sites iroquoiens de la région de Saint-Anicet: McDonald, Droulers et Mailhot-Curran. L’objectif est de mieux comprendre la fonction de ces objets fréquents sur les sites archéologiques iroquoiens, étant donné que la fonction précise est soit inconnue, soit présumée de façon spéculative. Pour répondre à cette question de recherche, l’analyse se déploie en trois volets : expérimental, analytique et comparatif. Le premier permettra d’éclairer la relation entre différentes matières travaillées et les traces laissées sur les outils en incisives de castor, ainsi que les mouvements effectués et la durée d’utilisation. Le deuxième volet aborde la tracéologie des incisives de castor de nos trois sites à l’étude, à partir des résultats des expérimentations. Le troisième volet de l’étude est dédié à la comparaison inter-sites. Ce projet permet de déterminer à quelles activités les outils sur dents de castor des collections ont servi, puis de comprendre les choix qui les sous-tendent. Cela permet donc de mieux comprendre l’humain derrière l’objet. Les résultats des analyses ont permis de démontrer l’utilisation des incisives de castor iroquoiennes comme outils servant à travailler le bois, mais plus spécifiquement comme outils servant à travailler des bois verts, tendres et mi-durs. De plus, il a été confirmé que les incisives de castor à double fonction, ciseau-racloir, sont le résultat d’outils recyclés ou réutilisés qui servaient à des usages divers. / This dissertation presents a traceological analysis, that is to say the functional analysis of an object based on microtraces of wear, applied to a collection of beaver incisors from Iroquoian sites in the Saint-Anicet region. : McDonald, Droulers and Mailhot-Curran. The goal is to better understand the function of these common objects at Iroquoian archaeological sites, given that the precise function is either unknown or speculated speculatively. To answer this research question, the analysis is deployed in three parts: experimental, analytical and comparative. The first will shed light on the relationship between different materials worked and the traces left on beaver incisor tools, as well as the movements made and the duration of use. The second part addresses the traceology of beaver incisors from our three sites under study, based on the results of the experiments. The third part of the study is dedicated to the inter-site comparison. This project makes it possible to determine what activities the beaver tooth tools in the collections were used for, then to understand the choices behind them. This therefore allows us to better understand the human behind the object. The results of the analyzes demonstrated the use of Iroquoian beaver incisors as tools for working wood, but more specifically as tools for working green, soft and semi-hard wood. Furthermore, it was confirmed that the double-function beaver incisors, chisel-scraper, are the result of recycled or reused tools that were used for various purposes.

Från 1900-talets början har banker och låneinstitut använt nyckeltal som hjälpmedel vid bedömning och kvantifiering av kreditrisk. För dagens investerare är den ekonomiska miljön mer komplicerad än för bara 40 år sedan då teknologin och datoriseringen öppnade upp världens marknader mot varandra. Bedömning av kreditrisk idag kräver effektiv analys av kvantitativa data och modeller som med god träffsäkerhet kan förutse risker. Under 1900-talets andra hälft skedde en snabb utveckling av de verktyg som används för konkursprediktion, från enkla univariata modeller till komplexa data mining-modeller med tusentals observationer. Denna studie undersöker om det är möjligt att prediktera att svenska företag kommer att gå i konkurs och vilka variabler som innehåller relevant information för detta. Metoderna som används är diskriminantanalys, logistisk regression och överlevnadsanalys på 50 aktiva och 50 företag försatta i konkurs. Resultaten visar på en träffsäkerhet mellan 67,5 % och 75 % beroende på vald statistisk metod. Oavsett vald statistisk metod är det möjligt att klassificera företag som konkursmässiga två år innan konkursens inträffande med hjälp av finansiella nyckeltal av typerna lönsamhetsmått och solvensmått. Samhällskostnader reduceras av bättre konkursprediktion med hjälp av finansiella nyckeltal vilka bidrar till ökad förmåga för företag att tillämpa ekonomistyrning med relevanta nyckeltal i form av lager, balanserad vinst, nettoresultat och rörelseresultat. / From the early 1900s, banks and lending institutions have used financial ratios as an aid in the assessment and quantification of credit risk. For today's investors the economic environment is far more complicated than 40 years ago when the technology and computerization opened up the world's markets. Credit risk assessment today requires effective analysis of quantitative data and models that can predict risks with good accuracy. During the second half of the 20th century there was a rapid development of the tools used for bankruptcy prediction. We moved from simple univariate models to complex data mining models with thousands of observations. This study investigates if it’s possible to predict bankruptcy in Swedish limited companies and which variables contain information relevant for this cause. The methods used in the study are discriminant analysis, logistic regression and survival analysis on 50 active and 50 failed companies. The results indicate accuracy between 67.5 % and 75 % depending on the choice of statistical method. Regardless of the selected statistical method used, it’s possible to classify companies as bankrupt two years before the bankruptcy occurs using financial ratios which measures profitability and solvency. Societal costs are reduced by better bankruptcy prediction using financial ratios which contribute to increasing the ability of companies to apply financial management with relevant key ratios in the form of stock , retained earnings , net income and operating income.