Original estimates of phosphorus (P) concentrations in the Precambrian oceans before 1.9 Ga gave a budget of ~10-25% of modern day levels. This budget was challenged by accounting for high silica (Si) concentrations that were believed to have outcompeted P for binding sites on precipitating iron oxide-hydroxide particles during the chemical oxidation and burial of iron (Fe). Such iron oxide-hydroxide particles are considered as proxies of ancient iron-rich sedimentary rocks, such as banded iron formations, which are often used to infer the dissolved chemistry of trace elements in the ancient oceans. This study raises the question of wether arsenic (As) had an effect of the binding of P to precipitating iron minerals, during the co-precipitation of Iron oxide- hydroxide in elevated Fe and Si concentrations characteristic of the early oceans. This hypothesis is based on the chemical similarities seen between P and As. Results show a more pH dependent competition between P and AsIII, whereby P outcompetes AsIII at a pH <7. The effect decreases as the pH rises until pH ~8 at which the effect cancels out and AsIII becomes somewhat predominant over P. AsV on the other hand, an analogue to P, is outcompeted by P throughout pH 5-10. Distribution coefficients (Kd) of P on iron oxide-hydroxide particles were not affected by the concentration of Si in solution. Average Kd and standard error between concentrations of Si, across the sample pH of 5-10 revealed an average Kd of 0.072 (±0.01) μM-1. This is strikingly similar to another experimental Kd at 0.075 (±0.003) μM-1, when the effects of Si are excluded. The average Kd in this study is also consistent with the average Kd of 0.06 μM-1 from a range of As-rich hydrothermal systems reported in a previous study, supporting the original idea of Precambrian P levels being low. The average Kd between concentrations of Fe revealed a Kd of 0.12 (±0.03) μM-1 although this was not statistically significant from the average Kd between groups of Si. In addition to low levels of P, the Precambrian oceans likely also contained high levels of As, due to the high hydrothermal activity. This scavenging of P from oceanic waters would have become increasingly important as surface oceans became more oxygenated and the presence of AsV would have been greater. Because the availability of Si does not show any great effect on the uptake of P by precipitating iron oxide-hydroxides, Si concentration is likely not a proxy for oceanic P concentrations. It is proposed that low dissolved P levels are consistent with early oceans that w!ere a lot more hydrothermally influenced than the oceans of today. / Prekambriska fosfor (P) nivåer var ursprungligen estimerade till ca 10-25% utav koncentrationen funnen i dagens havsvatten. Denna budget blev motsagd i och med att kisel (Si) sades kunna ersätta bundet fosfor på järn oxid-hydroxid partiklar som precipiterade genom kemisk oxidation och sedimentering av järn (Fe). Dessa järn oxid-hydroxid partiklar anses användbara som proxy för formationen av uråldriga järn-rika sedimentära bergarter såsom banded iron formation (BIF), vilka används idag för att bestämma mängden spårämnen i de uråldriga haven. Denna studie ställer frågan huruvida arsenik (As) påverkar mängden P som binder till precipiterande järn mineral under procession av co-precipitering av järn oxid-hydroxid i lösning med förhöjda koncentrationer av Fe och Si, karakteristiska för the uråldriga haven. Denna hypotes är baserad på de kemiska likheter som finns mellan P och As. Resultaten påvisar en pH beroende konkurrens mellan P och AsIII där P utkonkurrerar AsIII vid låg pH. Effekten av denna konkurrans minskar med ökande pH tills effekten blir omvänd omkring pH 8 och P blir istället till viss del utkonkurrerad av AsIII. AsV å andra sedan, en verklig kemisk analog till P, är kontinuerligt utkonkurrerad av P genom alla utförda pH, pH 5-10. Distribueringskoefficienter (Kd) för P på järn oxid-hydroxid partiklar visade ingen påverkan av mängden Si tillgängligt. Medelvärdet av Kd och standard error mellan data av alls pH, grupperat av Si, gav ett värde av 0.072 (±0.01) μM-1. Detta är påfallande nära ett experimentellt framtaget Kd värde av 0.075 (±0.03) μM-1 då effekten av Si är borttagen. Medelvärdet i denna studie är också sammanfallande med det Kd medelvärde man finner idag från olika hydrotemala system av 0.063 (±0.01) μM-1. Detta ger support till den originala idén att de prekambriska haven troligen hade låga halter P tillgängligt. Medelvärdet av Kd mellan koncentrationer av Fe gav ett värde av 0.12 (±0.03) μM-1, dock var detta värde ej statistiskt significant från det Kd utifrån koncentrationer av Si. Förutom de låga nivåer av P i de Prekambriska haven så var det troligen även höga halter av As på grund av utbredd hydrotermal aktivitet. Detta uppfångande av P i de tidiga haven var troligen en alltmer viktigare process då ytvatten blev syrerikare och den oxiderade formen av As, det vill säga AsV hade varit mer vanligt förekommande. Framför allt då den konkurrerande effekten av Si kan bortses när P såväl som As inte påverkas av dess närvaro till den grad man hade trott. Detta gör även att mängden Si troligen inte är en tillförlitlig proxy för att estimera P nivåer i de uråldriga haven. Därmed föreslås det att de prekambriska haven var k!arakteriserade av låga P nivåer, jämfört med idag.

Made available in DSpace on 2014-08-20T14:31:33Z (GMT). No. of bitstreams: 1 dissertacao_samara_nunes_gomes.pdf: 1205459 bytes, checksum: 4b65ad22706005a16a5b41efac9fe550 (MD5) Previous issue date: 2010-10-08 / Armadillos belong to the order Cingulata and are included in the superorder Xenarthra, which also belong to sloths and anteaters, hairy members of the order, which were restricted to the Neotropical region, occurring mainly in South America. Popularly known as nine banded armadillo, Dasypus novemcinctus occurs in the southern United States to South America, with wide distribution in Brazil. They are of great importance in the epidemiology of parasitc diseases, and potential disseminators of zoonoses. Since knowledge of helminths is important because it may assist in making decisions on future actions preservationists, as well as parasite control programs in these animals in captivity in zoos, therefore, the objective was to identify the helminths that parasitize Dasypus novemcinctus, in southern Rio Grande do Sul. The experiment consisted of examining 30 specimens of D. novemcinctus from the municipalities of Arambaré, Camaquã, Cristal, São Lourenço do Sul, Capão do Leão e Pinheiro Machado, taken with the permission of SISBIO / RS and trampled on the access roads to these towns. The animals were necropsied, had their organs removed, individually and separately analyzed by stereomicroscope to collect helminths. Parasites of the phylum Nematoda were identified as Bairdascaris dasypodina, Schneidernema retusa, Aspidodera ansirupa, A. binansata, A. fasciata, Physaloptera sp., Dipetalonema sp., Capillaria sp., Moennigia lutzi, M. Moennigi and M. filamentosus. Most nematodes were found in the small intestine, except for aspidoderids and S. retusa, which were present in the cecum. The cestode found was Mathevotaenia sp. and the acanthocephalan, Centrorhynchus sp. parasitizing both the small intestine. All nematodes are being cited for the first time in this host, in Rio Grande do Sul and cestode and acanthocephalan parasite have their first record in Dasypus novemcinctus in Brazil. / Os tatus pertencem à ordem Cingulata e estão incluídos na superordem Xenarthra, à qual pertencem também as preguiças e os tamanduás, membros da ordem Pilosa, sendo restritos à região Neotropical e ocorrem predominantemente na América do Sul. Conhecido popularmente como tatu-galinha, Dasypus novemcinctus ocorre do sul dos Estados Unidos até a América do Sul, com ampla distribuição no Brasil. São de grande importância na epidemiologia de doenças parasitárias, sendo possíveis disseminadores de zoonoses. O conhecimento dos helmintos é importante, pois poderá auxiliar na tomada de decisões em ações preservacionistas, como em programas de controle parasitário destes animais quando em cativeiro nos zoológicos. Sendo assim, o objetivo deste trabalho foi identificar os helmintos que parasitam Dasypus novemcinctus, no sul do Rio Grande do Sul. O experimento constou do exame de 30 espécimes de D. novemcinctus provenientes dos municípios de Arambaré, Camaquã, Cristal, São Lourenço do Sul, Pelotas, Capão do Leão e Pinheiro Machado, capturados mediante a autorização do SISBIO/RS bem como atropelados nas rodovias de acesso a esses municípios. Os animais foram necropsiados, tiveram seus órgãos retirados, individualizados e analisados separadamente ao estereomicroscópio para a coleta de helmintos. Os parasitos do Filo Nematoda foram: Bairdascaris dasypodina, Schneidernema retusa, Aspidodera ansirupa, A. binansata, A. fasciata, Physaloptera sp., Dipetalonema sp., Capillaria sp., Moennigia lutzi, M. moennigi e M. filamentosus. A maioria dos nematóides foi encontrada no intestino delgado, com exceção dos aspidoderídeos e de S. retusa, que estavam presentes no ceco. Da Classe Cestoda foi encontrado Mathevotaenia sp. e do Filo Acanthocephala, Centrorhynchus sp., ambos parasitando o intestino delgado. Todos os nematóides estão sendo citados pela primeira vez, neste hospedeiro, no Rio Grande do Sul e o cestóide e o acantocéfalo têm seu primeiro registro parasitando Dasypus novemcinctus no Brasil.

The problem of estimating mean and covariances of a multivariate normal distributedrandom vector has been studied in many forms. This thesis focuses on the estimatorsproposed in [15] for a banded covariance structure with m-dependence. It presents theprevious results of the estimator and rewrites the estimator when m = 1, thus makingit easier to analyze. This leads to an adjustment, and a proposition for an unbiasedestimator can be presented. A new and easier proof of consistency is then presented.This theory is later generalized into a general linear model where the correspondingtheorems and propositions are made to establish unbiasedness and consistency. In thelast chapter some simulations with the previous and new estimator verifies that thetheoretical results indeed makes an impact.

Algoma-type banded iron formation is common in Neoarchean greenstone belts, and many of its distinctive features such as the banding of iron-rich and silica-rich material and deposition in volcanic terranes have been ascribed to their deposition related to volcanic-hydrothermal activity and cyclic variability in depositional pathways. The work presented in this thesis tests these assumptions and presents a model for the deposition and post-depositional processes now represented by the petrography and geochemistry of a 2.73 Ga type-locality of Algoma-type BIF in Temagami, ON. Adsorption of components onto the surface of Fe-oxyhydroxides forming in the anoxic Neoarchean water column is the most likely process capable of transferring silica, as well as trace quantities of transition metals, rare earth elements, Ge, P, U and other components to the sediment. The petrogenesis of the Temagami BIF lithologies suggests ongoing recrystallization processes and volume loss reactions leading to the formation of magnetite layers, while jasper is identified as the most pristine lithology best representative of the initially deposited Fe-oxyhydroxide-silica gel. Recrystallization and volume loss reactions are controlled by the ongoing dewatering during compaction and diagenesis, without the influence of external hydrothermal or metamorphic fluids. When corrected for the volume loss and small amounts of clastic contamination, little residual variability can be observed in the composition of jasper and magnetite layers, indicative of an originally homogenous primary precipitate instead of sorted and layered material deposited on the seafloor. This model is in stark contrast to previous interpretations of seasonal variability in biologic activity, cyclical seasonal or hydrothermal events responsible for primary layering in BIF. Instead, very little direct input of hydrothermal components is recorded in the chemistry of the Temagami BIF, and elements abundant in high-temperature hydrothermal fluids such as sulfur are instead sourced from atmospheric sources and deposited by bacterial pathways. Lack of primary chemical variability and non-hydrothermally sourced components captured in BIF argue against a genetic link to local hydrothermal venting, but rather an open ocean depositional setting. As such, the Temagami BIF does not represent a marker horizon related to local or regional hydrothermal venting and potential formation of associated massive sulfide deposits but reflects processes and the chemistry of the open Neoarchean ocean.

The purpose of this study has been to determine the identity and the life history of certain larvae attacking dewberry fruits and foliage in a few sections of Utah. The dewberry fruit worm as it was called until it was definitely identified the oblique-banded leaf-roller, was first observed by farmers at Granite and Butlerville in 1932. Since 1934 it has been found affecting dewberries in other parts of northern Utah. This investigation was begun in the spring of 1935 and continued until the fall of 1936, being made possible through the Utah Agricultural Experiment Station, Department of Entomology, and with the cooperation of various farmers in the vicinity of Granite, Utah. Field studies were made at Granite, Butlerville and southeast Pleasant Grove during the course of the investigation. Overwintering studies were carried on at Logan during the winter of 1935-36. Since this insect is one of the most important pests of dewberries in Utah a careful study of its life history and habits was considered necessary before control methods were undertaken.

<p> The East South C (E.S.C.) ore zone at the Dickenson Mine, Red Lake, is a major auriferous banded sulphide orebody which cross-cuts sulphide facies banded iron formation (S.F.B.I.F.) near its eastern termination. Pyrite was obtained from sulphide-rich portions of the ore zone as well as from sulphide-poor E.S.C. mineralization not spatially associated with S.F.B.I.F., S.F.BI.F., shear zone hosted mineralization such as the 1492 and F ore zones, and from quartz-carbonate vein mineralization in the South C ore zone. Forty-three pyrite separates from the zones were analyzed by Atomic Absorption Spectrophotometry for Co and Ni, in order to determine the origin of the E.S.C. ore zone. The average Ni and Co content of these pyrites are as follows: S.F.B.I.F.,7.9 and 13.6 ppm respectively; remobilized S.F.B.I.F. 10.3 and 13.6; carbonatized S.F.B.I.F. 10.9 and 22.6; South C 14.9 and 50.6; 1492 zone 34.1 and 28.4; F-zone 11.2-27.6; sulphide-poor E.S.C. 26.2 and 48.4 and sulphide-rich E.S.C., 17.91 and 16.63.</p> <p> High and variable Co values were found to be associated with carbonate-rich samples, irrespective of the type of mineralization and low and similar Co values were found in all carbonate-poor samples irrespective of their origin. Therefore, the Co content of pyrite cannot be used as a discriminant of genetically dissimilar pyrite. The Ni content in pyrite from S.F.B.I.F. is low and constant, while in shear zone and vein mineralization it is higher and more variable. The E.S.C. ore zone has similar values to that found in the epigenetic mineralization, however, a few sulphide-rich samples are similar to those found in S.F.B.I.F., suggesting a bimodal source of sulphide for the E.S.C.. It is proposed that the hydrothermal system which produced the E.S.C., 1492, F and South C ore zones, locally incorporated sulphides from the S.F.B.I.F. to produce the sulphide-rich mineralization found at the eastern extremity of the E.S.C. ore zone.</p> / Thesis / Bachelor of Science (BSc)

The spotted cucumber beetle (Diabrotica undecimpunctata howardi Barber) is regarded as a pest of sweetpotatoes in Mississippi; however, its feeding on sweetpotatoes has not previously been documented. They are attracted to cucurbit crops that could be utilized as a trap crop or sentinel plant for management of cucumber beetles in sweetpotatoes. Studies were conducted between 2006 and 2008 to determine if cucurbit plants have the potential to serve as a trap crop or as sentinel plants for the spotted cucumber beetle in sweetpotato fields, and to determine the status of the spotted cucumber beetle as a sweetpotato pest in Mississippi. Cucurbit plants showed some potential to serve as a trap crop or sentinel plant for the spotted cucumber beetle, however, sweetpotato damage assumed to be caused by cucumber beetle larvae did not correlate with the number of adults captured. Spotted cucumber beetle larvae can feed and survive on sweetpotato roots.

Effectively developing robust predictive models for forecasting infectious disease dynamics over space and time relies on successful surveillance strategies to accurately assess host infection status. We are constantly refining these models to improve our understanding of transmission and persistence dynamics in host populations but are continuously challenged with difficulties in accurately diagnosing host infection status. These challenges are especially persistent for pathogens of the Mycobacterium tuberculosis Complex (MTBC), which cause tuberculosis (TB) disease in a wide array of mammalian hosts. These challenges are further exacerbated when working with MTBC pathogens in free-ranging wildlife hosts. Although TB disease in humans is a primary concern, TB in free-ranging wildlife hosts poses a large threat to human and animal health. One recently described and novel MTBC pathogen is Mycobacterium mungi, which infects the highly social, group-living banded mongoose (Mungos mungo). M. mungi poses a large threat to human and animal health as banded mongoose hosts thrive in urbanized areas and live in close proximity to humans, but despite this threat, accurately diagnosing M. mungi infection status remains a primary challenge. Here, I develop a host response-based assay for differentiating banded mongoose with clinical M. mungi disease from individuals that are putatively healthy using transcriptional biomarkers in whole blood. To our knowledge, this is the first evaluation of host response-based transcriptional signatures to detect TB infection in unstimulated whole blood collected from a free-ranging wildlife species. I found that the expression of two genes, GBP5 and DUSP3, are significantly upregulated (GBP5, p < .05; DUSP3, p < .005) in banded mongoose with clinical M. mungi disease when compared to that of putatively healthy individuals. These results are consistent with studies of active M. tuberculosis disease in humans and support the use of host response-based assays using blood transcriptional biomarkers for diagnosing TB in free-ranging wildlife hosts. These findings are important for improving surveillance strategies for diagnosing M. mungi infection status in banded mongoose and will be essential in refining predictive models for forecasting transmission and persistence dynamics over space and time. / Creating models to predict how diseases circulate and persist within a population is dependent on our ability to accurately diagnose if a host is infected. Diagnosing infection is difficult for some diseases, including tuberculosis (TB) pathogens, which infect humans and many other mammalian species. While vast improvements have been made in diagnosing TB infection in humans, diagnosing TB in free-ranging wildlife species is a constant challenge. These challenges are further exacerbated across the different pathogen species of TB. Although TB disease in humans is a primary concern, TB in free-ranging wildlife hosts poses a large threat to human and animal health. One recently discovered TB pathogen is Mycobacterium mungi, which infects free-ranging banded mongoose (Mungos mungo). This pathogen poses a large threat to human and animals health since banded mongoose thrive in urbanized areas and live in close proximity to humans. Despite this threat, accurately diagnosing M. mungi infection in banded mongoose remains a challenge. Here, I develop a diagnostic molecular tool that uses banded mongoose blood to measure the expression of specific genes and differentiate diseased individuals from seemingly healthy individuals. To our knowledge, this is the first study that has used this specific approach for diagnosing TB in a free-ranging wildlife species. I found that the expression of two genes are significantly increased in banded mongoose with clinical M. mungi disease when compared to that of seemingly healthy individuals. These results are consistent with studies human TB disease in humans and support the use of this approach for diagnosing TB in free-ranging wildlife hosts. These findings are important for improving diagnostics for M. mungi infection in banded mongoose and will be essential in refining models for predicting how this disease circulates and persists over space and time.

This research was focused on increasing the efficiency of upland cotton production in the northern cotton belt through the use of new fertilizer formulations, placement, and timings. The objectives of the experiments reported in this thesis were to: 1) evaluate the effects of side-dress potassium (K), sulfur (S), and boron (B) formulation and application timing on tissue nutrient levels during the bloom period; 2) evaluate lint yield response of cotton to different formulations of nitrogen (N), K, S and B applied at side-dress; and 3) compare 5x5 banding (5 cm beside and 5cm below the seed) and deep placement of complete N-P-K-S blends to current nutrient management strategies on early season plant growth, nodes above white flower, total nodes, petiole nutrient concentrations during bloom, and lint yield. Tissue S and B concentrations were increased more often than K concentrations when the nutrients were applied with side-dress N. When evaluating P and K placement, petiole P levels were found to be significantly higher in unfertilized plots when no side-dress N was applied. Phosphorus and K placement and/or rate had no effect on lint yield when N was applied at side-dress during the study. Environmental conditions potentially influenced the response to P and K placement as 5x5 placement produced yields significantly higher during 2013 growing season at location 1, while deep placement produced significantly higher yields in 2014 at location 3. As a result, Virginia nutrient management recommendations for cotton have been updated to incorporate management strategies to maximize lint yields. / Master of Science

A dissertação tem por cerne dois textos complementares, ambos refletindo o histórico de um programa de exploração mineral no distrito ferrífero de Curral Novo do Piauí. Como trabalho executado por empresa, a discussão sobre os custos e a definição de prioridades foram aspectos continuamente considerados. Assim os textos referidos refletem essas preocupações e se referem à proposição de métodos voltados à definição dos ambientes geológicos propícios à ocorrência de formações ferríferas à magnetita e à definição de probabilidade de ocorrências destes ambientes na fase de reconaissance da pesquisa. Na contextualização geológica do tema apresenta-se aspectos da geologia e uma discussão dos tipos e origens das formações ferríferas bandadas. Nos trabalhos foram aplicadas diversas técnicas, incluindo estatística multivariada, processamento digital de imagens, mapeamento geológico sistemático de superfície e subsuperfície em testemunhos de sondagens, caracterização petrográfica de rochas, geofísica de exploração a partir da utilização de métodos potenciais (magnetometria e radiometria). / This dissertation presents two complementary manuscripts, both reflecting the history of an exploration program in the Ferriferous Mineral District of Curral Novo do Piauí. As a research performed by a company, the discussion about the costs and prioritization aspects were continuously considered. The manuscripts reflects these concerns, referring to the proposition of methods aimed at defining the geological environments conducive to the occurrence of magnetite iron formations and the definition of probability of occurrence of these environments during the research reconnaissance phase. In the introductory chapter are presented the geological context and also a discussion of types and genesis of banded iron formations. In these studies were applied several techniques, including multivariate statistics, digital image processing, systematic geological surface mapping, diamond drill surveys, petrographic characterization of rocks and exploration geophysics methods (magnetometric and radiometric).