No description available.

No / In this paper, it is demonstrated how Raman spectroscopy can be used to detect different carotenoids as possible biomarkers in various groups of microorganisms. The question which arose from previous studies concerns the level of unambiguity of discriminating carotenoids using common Raman microspectrometers. A series of laboratory-grown microorganisms of different taxonomic affiliation was investigated, such as halophilic heterotrophic bacteria, cyanobacteria, the anoxygenic phototrophs, the non-halophilic heterotrophs as well as eukaryotes (Ochrophyta, Rhodophyta and Chlorophyta). The data presented show that Raman spectroscopy is a suitable tool to assess the presence of carotenoids of these organisms in cultures. Comparison is made with the high-performance liquid chromatography approach of analysing pigments in extracts. Direct measurements on cultures provide fast and reliable identification of the pigments. Some of the carotenoids studied are proposed as tracers for halophiles, in contrast with others which can be considered as biomarkers of other genera. The limits of application of Raman spectroscopy are discussed for a few cases where the current Raman spectroscopic approach does not allow discriminating structurally very similar carotenoids. The database reported can be used for applications in geobiology and exobiology for the detection of pigment signals in natural settings.

本研究旨在由傳統財務指標及公司治理角度分析近年來我國因財務報表舞弊遭一審判決有罪之公司發生的舞弊警訊(Red Flags)，建立財務報表舞弊預警模型，作為會計師執行舞弊偵測時的參考，降低因查核舞弊所產生的審計失敗，並可作為主管機關實質審查選案標準及投資人選擇投資標的之參考。 本文以民國85年至95年因財務報表舞弊遭法院一審判決有罪之27家公司為樣本，分別使用財務及公司治理變數建立財務報表舞弊預警模型，再以Cascade Logistic迴歸分析結合財務及公司治理模型，檢視Cascadev Logistic模型的正確判別率。實證結果顯示，財務變數中舞弊當期應付帳款成長率、舞弊當期存貨成長率、應收帳款收現天數對前期同一比率與財務報表舞弊呈顯著正相關；舞弊當期資產報酬率對前期同一比率、舞弊當期銷貨成長率與財務報表舞弊呈顯著負相關。公司治理變數中董監持股、控制持股、外部個人監事席次與財務報表舞弊顯著負相關；財報重編次數呈顯著正相關，良善的公司治理機制與財務舞弊具負向關連性。而整合的Cascade Logistic模型，財務及公司治理變數均與財務報表舞弊呈顯著相關，且均具增額解釋。 / Presented are a profile of a sample of fraud companies in Taiwan from 1996 to 2006, their financial and corporate governance characteristics, suggested fincial and corporate governance logistic models for detecting fraud and a final combine cascade logistic model. The results suggest both systematic relationships between the probability of fraud and financial and corporate governance characteristic variables. This evidence is consistent with the usefulness of accounting data in detecting fraud and the effectiveness of proper corporate governance in protecting fraud happening. Because the cascade logistic model correctly identifies approximately 90% of the companies involved or not invleved in fraud, the model can be a useful screening device for auditors to detect fraud, low down the propobility of audit failure and the cost of lawsuit due to fraud.

Orientador: Marcelo Muniz Silva Alves / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-12T16:23:24Z (GMT). No. of bitstreams: 1 Ritter_Donizete_M.pdf: 621556 bytes, checksum: 2bf0368b784f3a2be59ca3c2552f4908 (MD5) Previous issue date: 2009 / Resumo: Neste trabalho abordamos a teoria dos Códigos Corretores de Erros clássica e também os códigos sobre ordens parciais, com algumas comparações entre os dois casos. Enfocamos, particularmente, a definição de Alfabeto, a distância de Hamming, os códigos lineares e a definição de matriz geradora de um código; o estudo dos limitantes de Singleton e de Hamming, além de tratar dos Códigos de Hamming. Em relação aos Códigos em Conjuntos Parcialmente Ordenados, apresentamos a definição de ordens parciais, métricas sobre conjuntos ordenados, contagem dos elementos da "bola", resultados sobre Ideais e o Código de Hamming Estendido; estudamos o caso da ordem cadeia ("chain poset"), analisando os códigos de uma cadeia e os códigos de duas cadeias de mesmo comprimento e, por fim, nos dedicamos ao estudo das "Métricas POSET", que admitem códigos binários perfeitos de codi-mensão m, caracterizando assim os Códigos Posets m-corretores de erros. Nosso objetivo é apresentar um texto, acessível a alunos de graduação, que contemple a teoria básica dos Códigos Corretores de Erros, no entanto, forneça uma noção sobre os códigos sobre ordens parciais. / Abstract: In this work, we address the classical theory of error-correcting codes and the theory of codes over poset spaces, also known as poset codes, establishing comparisons between these two cases. In particular, we present the definition of alphabet, the Hamming distance, linear codes and the definition of a generating matrix for a linear code; we also present the Singleton and Hamming bounds, alongside with the Hamming codes. With respect to poset codes, we present the definitions of partial orders and of the poset metric, the counting of the number of elements in a ball in a poset space, some results on ideals in posets and the extended Hamming code; we study the chain poset case, analysing the cases of codes over a chain poset and codes over a union of two chains of the same length and, finally, we study the poset metrics that allow m-perfect binary codes of codimension m, thus characterizing these codes. Our aim is to present a text, accessible for undergraduates, that encompasses the basic theory of error-correcting codes and, nonetheless, also provides some notions on poset codes. / Mestrado / Teoria dos Erros / Mestre em Matemática

No description available.

Cryptosystems based on elliptic curves are in wide-spread use, they are considered secure because of the difficulty to solve the elliptic curve discrete logarithm problem. Pollard's rho method is regarded as the best method for attacking the logarithm problem to date, yet it is still not efficient enough to break an elliptic curve cryptosystem. This is because its time complexity is O(√n) and for uses in cryptography the value of n will be very large. The objective of this thesis is to see if there are ways to improve Pollard's rho method. To do this, we study some modifications of the original functions used in the method. We also investigate some different functions proposed by other researchers to see if we can find a version that will improve the performance. From the experiments conducted on these modifications and functions, we can conclude that we get an improvement in the performance for some of them.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-06-14T15:45:26Z No. of bitstreams: 1 Rafael Herzer_.pdf: 1397260 bytes, checksum: a9941bd0932b535c5699cf0b35a815dc (MD5) / Made available in DSpace on 2016-06-14T15:45:26Z (GMT). No. of bitstreams: 1 Rafael Herzer_.pdf: 1397260 bytes, checksum: a9941bd0932b535c5699cf0b35a815dc (MD5) Previous issue date: 2016-02-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho tem como objetivo propor um método de monitoramento para gestão de portfólio, o qual, através de um sistema multi-critério e de um modelo econométrico, identifica variações no cenário econômico e em indicadores da empresa sendo então, a partir do monitoramento de resíduos, possível definir o momento exato para alteração de portfólio de produtos. A Gestão de Portfólio de produtos vem atraindo interesse dos gestores das corporações e deste modo, é difícil encontrar alguma organização que não possua uma carteira de produtos e projetos para gerenciar. A Gestão de Portfólio trata das decisões de alocação de recursos e de como ficará a carteira dos produtos atuais, sendo uma ferramenta de extrema importância para o resultado, principalmente financeiro, das organizações. Encontram-se vários métodos na literatura para realizar a Gestão do Portfólio, dentre os quais modelos financeiros, modelos probabilísticos financeiros, modelos de escores e checklists, abordagens de hierarquia analítica, abordagens comportamentais e abordagens de mapas ou diagrama de bolhas são os mais relevantes. Mesmo existindo diversos métodos na literatura para realizar a gestão do portfólio, não há consenso sobre qual método deve ser utilizado em cada etapa específica. Esses métodos também necessitam de intervenção dos gestores, levando em consideração que geralmente as informações disponíveis para tomada de decisão não são completas ou exatas. Para este estudo, foi realizado um estudo de simulação Monte Carlo para avaliar a sensibilidade dos diversos elementos que compõem o método. Os resultados mostraram taxas de alarmes falsos e tempo médio para detectar a mudança semelhantes a estudos anteriores. Esse processo de gestão e tomada de decisão é considerado complexo para os gestores das empresas, uma vez que o portfólio necessita ser periodicamente revisado, buscando sempre maximização de valor e equilíbrio ideal de produtos no mercado. Por fim, a aplicação do modelo é ilustrada por um caso real, utilizando dados fornecidos por uma empresa multinacional do segmento agrícola. / Product Portfolio Management is attracting the interest of the managers of the corporations. With the competitiveness of the market, it is difficult to find an organization that does not have a portfolio of products to manage. The Portfolio Management deals with resource allocation decisions and how will the portfolio of current products be compouse, being an extremely important tool for the result, especially financial, for the organizations. This process of management and decision making is considered complex to company managers, since the portfolio needs to be periodically revised, always seeking to maximize value and correct balance of products on the market. There are several methods in the literature to perform portfolio management, among which financial models, financial probabilistic models, scores and checklists models, analytical hierarchy of approaches, behavioral approaches and approaches map or diagram bubbles are the most relevant. While there are several methods in the literature to make the portfolio management, there is no consensus about which method should be used in each specific step. These methods also require the intervention of managers, taking into account that generally available information for decision-making are not complete or accurate. This paper aims to propose a method, which, through a multi-criteria system containing an econometric model, identifies changes in the economic environment and business indicators and then, from the profile monitoring, can set the exacly time for change portfolio of products. We performed the Monte Carlo simulation study to assess the sensitivity of the various parts that make up the method. The results showed false alarm rate and mean time to detect changes similar to previous studies. Finally, the application of the model is illustrated by a real case using data provided by a multinational company, agricultural segment.

Electron vortex beams (EVBs) are electron beams with a doughnut-like intensity profile, carrying orbital angular momentum due to their helical phase shift distribution. When employed in an electron microscope, they are expected to be efficient for the detection of magnetic signals. In this report I have investigated high angle annular dark field (HAADF) images obtained using EVBs. This was done for 300 K and 5K. For 5 K,  I also compared HAADF images from an ordinary electron beam with HAADF images from an electron vortex beam. What was found was that EVBs produced doughnuts around the atomic columns. However, when taking the size of the electron source into account, this phenomena could no longer  be observed. When comparing images from EVBs with images from ordinary electron beams, I found that the intensity of scattered electrons around atomic columns was broader for EVBs. This was persistent even after taking the source size into account. / Elektronvirvelstrålar (EVS) är elektronstrålar med en munk-liknande intensitetsprofil. Dessa bär på rörelsemängdsmoment på grund av sin fasdistribution. När de används i ett elektronmikroskop förväntas de vara effektiva för detektering av magnetiska signaler. I denna uppsats har jag undersökt high angle annular dark field (HAADF) bilder som erhållits med hjälp av EVS. Detta gjordes för 300 K och 5K. För 5 K, jämförde jag även HAADF bilder från en vanlig elektronstråle med HAADF bilder från en elektronvirvelstråle. Vad jag fann var att EVS producerade en munkformad intensitetsfördelning runt atomerna. Men när hänsyn till storleken på elektronkällan togs i beaktande kunde inte detta fenomen observeras längre. När bilder från EVS jämfördes med bilder från vanliga elektronstrålar, fann jag att intensiteten av spridda elektroner runt atomkolumnerna var bredare för EVS. Detta kunde observeras även efter att jag tagit hänsyn till elektronkällans storlek.

This thesis is an investigation of detecting and quantifying airborne inoculum of Sclerotinia sclerotiorum (Lib.) de Bary to improve the Sclerotinia rot of carrot (SRC) forecast model. A quantitative polymerase chain reaction (qPCR) assay was developed to specifically detect and quantify DNA from airborne ascospores of S. sclerotiorum. The qPCR assay was evaluated on air samples collected using a Burkard Sampler, and showed that ascospores of S. sclerotiorum were specifically detected among a pool of foreign DNA. The concentration of detected ascospores was related to the observed incidence of SRC to suggest a preliminary threshold of 2 to 4 ascospores m-3 of air for SRC development. Evaluation of an Andersen Sampler, the blue plate test (BPT) and the qPCR assay showed that the latter two methods were equally effective in detecting and quantifying ascospores of S. sclerotiorum and consistently detected greater numbers of ascospores than an Andersen Sampler. Three days are required to confirm the presence of S. sclerotiorum using the BPT, while results from the qPCR assay can potentially provide results within five hours of air sampling. The choice of detection method depends on the available resources and need for a quick result. Analysis of data from nine years of air sampling using the BPT indicated that a single air sampling site is sufficient to detect ascospores when counts are low, increasing to two sites during periods when ascospores are detected near threshold levels and crop and environmental conditions are conducive to disease. Chitosan and canopy trimming were evaluated to manage SRC under field conditions. Chitosan reduced area under the disease progress curve (AUDPC) by 55 and 42% in 2009 and 2011, respectively, which was comparable to a standard fungicide. Trimming enhanced chitosan efficacy, reducing AUDPC by 88 and 82% in 2009 and 2011, respectively. Trimming as a stand-alone treatment reduced AUDPC by 66% in 2011. Under controlled environmental conditions, chitosan inconsistently enhanced defense responses against S. sclerotinia. The results show that chitosan has potential to be integrated into SRC management systems, particularly when combined with foliar trimming in years with moderate to high disease risk. / National Research Council of Canada; University of Guelph; Department of Plant Agriculture; Ontario Ministry of Agriculture, Food and Rural Affairs

We broaden the theory of dynamical interpretation, investigate the property of commutativity and explore the subject of subgroups forming free products in Thompson's group V. We expand Brin's terminology for a revealing pair to an any tree pair. We use it to analyse the dynamical behaviour of an arbitrary tree pair which cannot occur in a revealing pair. Hence, we design a series of algorithms generating Brin's revealing pair from any tree pair, by successively eliminating the undesirable structures. To detect patterns and transitioning between tree pairs, we introduce a new combinatorial object called the chains graph. A newly defined, unique and symmetrical type of a tree pair, called a balanced tree pair, stems from the use of the chains graphs. The main theorem of Bleak et al. in "Centralizers in the R. Thompson's Group V_n" states the necessary structure of the centraliser of an element of V. We provide a converse to this theorem, by proving that each of the predicted structures is realisable. Hence we obtain a complete classification of centralisers in V. We give an explicit construction of an element of V with prescribed centraliser. The underlying concept is to embed a Cayley graph of a finite group into the flow graph (introduced in Bleak et al.) of the desired element. To reflect the symmetry, we present the resulting element in terms of a balanced tree pair. The group V is conjectured to be a universal coCF group, which generates interest in studying its subgroups. We develop a better understanding of embeddings into V by providing a necessary and sufficient dynamical condition for two subgroups (not both torsion) to form a free product in V. For this, we use the properties, explored in Bleak and Salazar-Díaz "Free Products in Thompson's Group V", of sets of so--called important points, and the Ping-Pong action induced on them.