392 research outputs found
Oracle warehouse management system-security enhancements
Estågio realizado na Wipro Retail e orientado pelo Doutora Ana Paula Barroso OliveiraTese de mestrado integrado. Engenharia Informåtica e Computação. Faculdade de Engenharia. Universidade do Porto. 200
Conception sur mesure d'un FPGA durci aux radiations à base de mémoires magnétiques
The aim of the thesis was to show that MRAM memory has many advantages for use as a configuration memory for reconfigurable architectures and especially Field Programmable Gate-Arrays (FPGAs). This type of component is programmable and allows designing a digital circuit simply by programming memory cells that define its functionality. An FPGA is thus mainly composed of memory cells. That is why they largely determine its characteristics as its surface or power consumption and affect its performance as its speed. MRAM memories are composed of Magnetic Tunnel Junctions (JTMs) which store information in the form of a magnetization. A JTM is composed of three layers: two layers of ferromagnetic material separated by an insulating layer. One of the two ferromagnetic layers has a magnetization pinned in a fixed direction (reference layer) while the other one can have its magnetization switched between two directions (storage layer). Thus, the propagation of the electrons is changed depending on whether the two magnetizations are parallel or antiparallel that is to say that the electrical resistance of the junction changes according to the orientation of the magnetizations. It is low when the magnetizations are parallel and high when antiparallel. Writing a JTM consists in changing the orientation of the magnetization of the storage layer while reading consists in determining if the resistance is high or low. The advantages of the JTM make it a good candidate to be used as a universal memory although research efforts are still needed. However, it has many advantages such as non-volatility, fast and low power consumption compared to writing to Flash memory as well as resistance to radiation. With these advantages, we may already use it in some applications and in particular in the field of space. Indeed, its use in this area allows taking advantage of all of the benefits of JTM due to the fact that it is intrinsically immune to radiation and non-volatile. It therefore enables to make a radiation hardened and low power FPGA with new functionalities. The work of this thesis is held over three years. The first year was dedicated to the state of the art in order to learn the mechanisms of JTMs, the architecture of FPGAs, radiation hardening and low power consumption techniques as well as the operation of the tools used in microelectronics. After the first year, a new FPGA architecture concept was proposed. The second and third years were devoted to the realization of this innovation with the search for the best circuit structure and the realization of an elementary component of a FPGA and the design and manufacture of a demonstrator. The demonstrator has been successfully tested and proved the new concept. The new circuit architecture of FPGA has shown that the use of MRAM cells as configuration memories for FPGAs was particularly advantageous for future technologies.Le but de la thĂšse a Ă©tĂ© de montrer que les cellules mĂ©moires MRAM prĂ©sentent de nombreux avantages pour une utilisation en tant que mĂ©moire de configuration pour les architectures reconfigurables et en particulier les FPGAs (Field Programmable Gate Arrays). Ce type de composant est programmable et permet de concevoir un circuit numĂ©rique simplement en programmant des cellules mĂ©moires qui dĂ©finissent sa fonctionnalitĂ©. Un FPGA est principalement constituĂ© de cellules mĂ©moires. C'est pourquoi elles dĂ©terminent en grande partie ses caractĂ©ristiques comme sa surface ou sa consommation et influencent ses performances comme sa rapiditĂ©. Les mĂ©moires MRAM sont composĂ©es de Jonctions Tunnel MagnĂ©tiques (JTMs) qui stockent l'information sous la forme d'une aimantation. Une JTM est composĂ©e de trois couches : deux couches de matĂ©riaux ferromagnĂ©tiques sĂ©parĂ©es par une couche isolante. Une des deux couches ferromagnĂ©tiques a une aimantation fixĂ©e dans un certaine direction (couche de rĂ©fĂ©rence) tandis que l'autre peut voir son aimantation changer dans deux directions (couche de stockage). Ainsi, la propagation des Ă©lectrons est changĂ©e suivant que les deux aimantations sont parallĂšles ou antiparallĂšles c'est-Ă -dire que la rĂ©sistance Ă©lectrique de la jonction change suivant l'orientation relative des aimantations. Elle est faible lorsque les aimantations sont parallĂšles et forte lorsqu'elles sont antiparallĂšles. L'Ă©criture d'une JTM consiste donc Ă changer l'orientation de l'aimantation de la couche de stockage tandis que la lecture consiste Ă dĂ©terminer si l'on a une forte ou une faible rĂ©sistance. Les atouts de la JTM font d'elle une bonne candidate pour ĂȘtre une mĂ©moire dite universelle, bien que des efforts de recherche restent Ă accomplir. Cependant, elle a de nombreux avantages comme la non-volatilitĂ©, la rapiditĂ© et la faible consommation Ă l'Ă©criture comparĂ©e Ă la mĂ©moire Flash ainsi que la rĂ©sistance aux radiations. GrĂące Ă ces avantages, on peut dĂ©jĂ l'utiliser dans certaines applications et en particulier dans le domaine du spatial. En effet, l'utilisation dans ce domaine permet de tirer parti de tous les avantages de la JTM en raison du fait qu'elle est intrinsĂšquement immune aux radiations et non-volatile. Elle permet donc de rĂ©aliser un FPGA rĂ©sistant aux radiations et avec une basse consommation et de nouvelles fonctionnalitĂ©s. Le travail de la thĂšse s'est donc dĂ©roulĂ© sur trois ans. La premiĂšre annĂ©e a d'abord Ă©tĂ© dĂ©diĂ©e Ă l'Ă©tat de l'art afin d'apprendre le fonctionnement des JTMs, l'architecture des FPGAs, les techniques de durcissement aux radiations et de basse consommation ainsi que le fonctionnement des outils utilisĂ©s en microĂ©lectronique. Au bout de la premiĂšre annĂ©e, un nouveau concept d'architecture de FPGA a Ă©tĂ© proposĂ©. Les deuxiĂšme et troisiĂšme annĂ©es ont Ă©tĂ© dĂ©diĂ©es Ă la rĂ©alisation de cette innovation avec la recherche de la meilleure structure de circuit et la rĂ©alisation d'un circuit de base d'un FPGA ainsi que la conception puis la fabrication d'un dĂ©monstrateur. Le dĂ©monstrateur a Ă©tĂ© testĂ© avec succĂšs et a permis de prouver le concept. La nouvelle architecture de circuit de FPGA a permis de montrer que l'utilisation des mĂ©moires MRAM comme mĂ©moire de configuration de FPGA Ă©tait avantageuse et en particulier pour les technologies futures
Utilisation de la spectromĂ©trie infrarouge pour une quantification rapide du taux dâhumiditĂ© dans des fibres vĂ©gĂ©tales
International audienceIn the field of composite materials, natural fibres appear to be a viable replacement for glass fibres. However, in humid conditions, strong hydrophilic behavior of such materials can lead to high level of moisture absorption. This feature can result in a structural modification of the fibres and a modification of their own mechanical properties as well as those of the composites they are fitted in. Then, understanding moisture sorption mechanisms in these materials is an important issue for their efficient use. In this work, water absorption on three natural fibres (flax, hemp and sisal) studied qualitatively and quantitatively using non-invasive approach, i.e. Fourier transformed infrared spectroscopy. Fibres with different moisture content were prepared using climatic chambers, allowing strictly controlled hygrothermal ageing. The equilibrium water content were assessed by gravimetric measurement and determined for each relative humidity conditions (Relative humidity ranging from 30 % until 97 %). The principal chemical functions of fibres involved in the water absorption phenomenon were thereby identified and the water content of tested fibres was determined using a Partial Least Square Regression approach. The typical sorption isotherm curves described by Park model were clearly fitted, confirming the validity of our predictive model. Finally, this model has been applied for monitoring the water diffusion.Les fibres vĂ©gĂ©tales sont une alternative possible aux fibres de verre utilisĂ©es classiquement comme renforts dans certains matĂ©riaux composites. En plus dâavantages environnementaux, leur faible densitĂ© leur confĂšre des propriĂ©tĂ©s mĂ©caniques spĂ©cifiques Ă©levĂ©es. Cependant, leur comportement hydrophile marquĂ© entraĂźne une forte absorption dâeau lors dâune utilisation en environnement humide, ce qui peut modifier leurs propriĂ©tĂ©s mĂ©caniques. La comprĂ©hension de ces mĂ©canismes dâabsorption dâhumiditĂ© est donc indispensable Ă leur maĂźtrise. Dans ce travail, lâabsorption dâeau a Ă©tĂ© Ă©tudiĂ©e par spectroscopie infrarouge Ă transformĂ©e de Fourier sur des fibres de lin, chanvre et sisal. Ces fibres ont Ă©tĂ© soumises Ă des conditions hygromĂ©triques contrĂŽlĂ©es. Les spectres infrarouges des Ă©chantillons ont Ă©tĂ© enregistrĂ©s en mode rĂ©flexion totale attĂ©nuĂ©e. Les informations spectrales ont permis de mettre en Ă©vidence les fonctions chimiques impliquĂ©es dans les mĂ©canismes dâabsorption de lâhumiditĂ© et de quantifier le taux dâhumiditĂ© retenu par les fibres. Pour cela, des modĂšles de rĂ©gression partielle des moindres carrĂ©s ont Ă©tĂ© dĂ©veloppĂ©s en exploitant des donnĂ©es expĂ©rimentales issues de mesures gravimĂ©triques. Ces modĂšles se sont rĂ©vĂ©lĂ©s de bons outils pour la caractĂ©risation des cinĂ©tiques de diffusion de lâeau dans ces diffĂ©rentes fibres
Estudo comparativo de custos entre um edifĂcio executado em alvenaria estrutural e em concreto armado
TCC (graduação) - Universidade Federal de Santa Catarina. Campus Joinville. Engenharia de Infraestrutura.Construtoras e investidores estĂŁo constantemente avaliando os diversos mĂ©todos construtivos de edificaçÔes, optando por aquele que proporcionar melhores resultados no que diz respeito Ă organização, racionalização e rapidez de execução. Ou seja, aquele que apresentar a melhor viabilidade tĂ©cnica e econĂŽmica. Sendo assim, o estudo proposto tem como objetivo comparar dois mĂ©todos amplamente utilizados na construção de edificaçÔes: o mĂ©todo construtivo em concreto armado com alvenaria de vedação, e o mĂ©todo construtivo em alvenaria estrutural com blocos cerĂąmicos. ApĂłs esse estudo comparativo, este trabalho objetivou comprovar a economia que o mĂ©todo em alvenaria estrutural pode gerar para uma construção em relação Ă alvenaria convencional, analisando as caracterĂsticas tĂ©cnicas das estruturas. A comparação dos custos de execução entre os mesmos se dĂĄ pela consideração dos custos de mĂŁo de obra e materiais necessĂĄrios para execução da superestrutura e alvenaria de uma determinada edificação. Para este estudo utilizou-se um projeto jĂĄ existente de um edifĂcio em alvenaria estrutural e com base neste projeto o mesmo edifĂcio foi projetado em estruturas de concreto armado. Com isso, pode-se executar a etapa de levantamento de dados, verificação de custos, e posteriormente o comparativo. Como resultado do estudo, o edifĂcio executado em alvenaria estrutural obteve uma economia de 28% em comparação ao executado em estruturas de concreto armado com alvenaria de vedação.Builders and investors are constantly evaluating the various constructive methods of buildings, opting for the one that provides better results in terms of organization, rationalization and speed of execution. That is, the one that presents the best technical and economic feasibility. Thus, the proposed study aims to compare two methods widely used in building construction: the constructive method in reinforced concrete and the constructive method in structural masonry with ceramic blocks. After this comparative study, this work aimed to prove the economics that the method in structural masonry can generate for a construction in relation to conventional masonry, analyzing the technical characteristics of the structures. The comparison of the economic viability between them is due to the consideration of the costs of labor and materials necessary to execute the superstructure and masonry of a given building. For this study was used an existing project of a building in structural masonry and based on this project the same building was designed in reinforced concrete structures. With this, you can perform the step of data survey, cost checking, and then comparative. As a result of the study, the building executed in structural masonry obtained a saving of 28% in comparison to that executed in structures of reinforced concrete with masonry of fence
Selection of biologically relevant genes with a wrapper stochastic algorithm
International audienceWe investigate an important issue of a meta-algorithm for selecting variables in the framework of microarray data. This wrapper method starts from any classification algorithm and weights each variable (i.e. gene) relative to its efficiency for classification. An optimization procedure is then inferred which exhibits important genes for the studied biological process. Theory and application with the SVM classifier were presented in Gadat and Younes, 2007 and we extend this method with CART. The classification error rates are computed on three famous public databases (Leukemia, Colon and Prostate) and compared with those from other wrapper methods (RFE, lo norm SVM, Random Forests). This allows the assessment of the statistical relevance of the proposed algorithm. Furthermore, a biological interpretation with the Ingenuity Pathway Analysis software outputs clearly shows that the gene selections from the different wrapper methods raise very relevant biological information, compared to a classical filter gene selection with T-test
Current Knowledge on Pancreatic Cancer
Pancreatic cancer is the fourth leading cause of cancer death with a median survival of 6âmonths and a dismal 5-year survival rate of 3â5%. The development and progression of pancreatic cancer are caused by the activation of oncogenes, the inactivation of tumor suppressor genes, and the deregulation of many signaling pathways. Therefore, the strategies targeting these molecules as well as their downstream signaling could be promising for the prevention and treatment of pancreatic cancer. However, although targeted therapies for pancreatic cancer have yielded encouraging results in vitro and in animal models, these findings have not been translated into improved outcomes in clinical trials. This failure is due to an incomplete understanding of the biology of pancreatic cancer and to the selection of poorly efficient or imperfectly targeted agents. In this review, we will critically present the current knowledge regarding the molecular, biochemical, clinical, and therapeutic aspects of pancreatic cancer
Localization and expression of nuclear factor of activated T-cells 5 in myoblasts exposed to pro-inflammatory cytokines or hyperosmolar stress and in biopsies from myositis patients
Aims: Regeneration in skeletal muscle relies on regulated myoblast migration and differentiation, in which the transcription factor nuclear factor of activated T-cells 5 (NFAT5) participates. Impaired muscle regeneration and chronic inflammation are prevalent in myositis. Little is known about the impact of inflammation on NFAT5 localization and expression in this group of diseases. The goal of this study was to investigate NFAT5 physiology in unaffected myoblasts exposed to cytokine or hyperosmolar stress and in myositis.
Methods: NFAT5 intracellular localization and expression were studied in vitro using a cell culture model of myositis. Myoblasts were exposed to DMEM solutions enriched with pro-inflammatory cytokines IFN-gamma with IL-1 beta) or hyperosmolar DMEM obtained by NaCI supplementation. NFAT5 localization was visualized using immunohistochemistry (IHC) and Western blotting (WB) in fractionated cell lysates. NFAT5 expression was assessed by WB and RT-qPCR. In vivo localization and expression of NFAT5 were studied in muscle biopsies of patients diagnosed with polymyositis (n = 6), dermatomyositis (n = 10), inclusion body myositis (n = 11) and were compared to NFAT5 localization and expression in non-myopathic controls (n = 13). Muscle biopsies were studied by means of quantitative IHC and WB of total protein extracts.
Results: In unaffected myoblasts, hyperosmolar stress ensues in NFAT5 nuclear translocation and increased NFAT5 mRNA and protein expression. In contrast, pro-inflammatory cytokines did not lead to NFAT5 nuclear translocation nor increased expression. Cytokines IL-1 beta with IFN-gamma induced colocalization of NFAT5 with histone deacetylase 6 (HDAC6), involved in cell motility. In muscle biopsies from dermatomyositis and polymyositis patients, NFAT5 colocalized with HDAC6, while in IBM, this was often absent.
Conclusions: Our data suggest impaired NFAT5 localization and expression in unaffected myoblasts in response to inflammation. This disturbed myogenic NFAT5 physiology could possibly explain deleterious effects on muscle regeneration in myositis
Identification of transcriptional signals in Encephalitozoon cuniculi widespread among Microsporidia phylum: support for accurate structural genome annotation
<p>Abstract</p> <p>Background</p> <p>Microsporidia are obligate intracellular eukaryotic parasites with genomes ranging in size from 2.3 Mbp to more than 20 Mbp. The extremely small (2.9 Mbp) and highly compact (~1 gene/kb) genome of the human parasite <it>Encephalitozoon cuniculi </it>has been fully sequenced. The aim of this study was to characterize noncoding motifs that could be involved in regulation of gene expression in <it>E. cuniculi </it>and to show whether these motifs are conserved among the phylum Microsporidia.</p> <p>Results</p> <p>To identify such signals, 5' and 3'RACE-PCR experiments were performed on different E. cuniculi mRNAs. This analysis confirmed that transcription overrun occurs in E. cuniculi and may result from stochastic recognition of the AAUAAA polyadenylation signal. Such experiments also showed highly reduced 5'UTR's (<7 nts). Most of the <it>E. cuniculi </it>genes presented a CCC-like motif immediately upstream from the coding start. To characterize other signals involved in differential transcriptional regulation, we then focused our attention on the gene family coding for ribosomal proteins. An AAATTT-like signal was identified upstream from the CCC-like motif. In rare cases the cytosine triplet was shown to be substituted by a GGG-like motif. Comparative genomic studies confirmed that these different signals are also located upstream from genes encoding ribosomal proteins in other microsporidian species including <it>Antonospora locustae</it>, <it>Enterocytozoon bieneusi</it>, <it>Anncaliia algerae </it>(syn. <it>Brachiola algerae</it>) and <it>Nosema ceranae</it>. Based on these results a systematic analysis of the ~2000 E. cuniculi coding DNA sequences was then performed and brings to highlight that 364 translation initiation codons (18.29% of total CDSs) had been badly predicted.</p> <p>Conclusion</p> <p>We identified various signals involved in the maturation of E. cuniculi mRNAs. Presence of such signals, in phylogenetically distant microsporidian species, suggests that a common regulatory mechanism exists among the microsporidia. Furthermore, 5'UTRs being strongly reduced, these signals can be used to ensure the accurate prediction of translation initiation codons for microsporidian genes and to improve microsporidian genome annotation.</p
Detecting variants with Metabolic Design, a new software tool to design probes for explorative functional DNA microarray development
<p>Abstract</p> <p>Background</p> <p>Microorganisms display vast diversity, and each one has its own set of genes, cell components and metabolic reactions. To assess their huge unexploited metabolic potential in different ecosystems, we need high throughput tools, such as functional microarrays, that allow the simultaneous analysis of thousands of genes. However, most classical functional microarrays use specific probes that monitor only known sequences, and so fail to cover the full microbial gene diversity present in complex environments. We have thus developed an algorithm, implemented in the user-friendly program Metabolic Design, to design efficient explorative probes.</p> <p>Results</p> <p>First we have validated our approach by studying eight enzymes involved in the degradation of polycyclic aromatic hydrocarbons from the model strain <it>Sphingomonas paucimobilis </it>sp. EPA505 using a designed microarray of 8,048 probes. As expected, microarray assays identified the targeted set of genes induced during biodegradation kinetics experiments with various pollutants. We have then confirmed the identity of these new genes by sequencing, and corroborated the quantitative discrimination of our microarray by quantitative real-time PCR. Finally, we have assessed metabolic capacities of microbial communities in soil contaminated with aromatic hydrocarbons. Results show that our probe design (sensitivity and explorative quality) can be used to study a complex environment efficiently.</p> <p>Conclusions</p> <p>We successfully use our microarray to detect gene expression encoding enzymes involved in polycyclic aromatic hydrocarbon degradation for the model strain. In addition, DNA microarray experiments performed on soil polluted by organic pollutants without prior sequence assumptions demonstrate high specificity and sensitivity for gene detection. Metabolic Design is thus a powerful, efficient tool that can be used to design explorative probes and monitor metabolic pathways in complex environments, and it may also be used to study any group of genes. The Metabolic Design software is freely available from the authors and can be downloaded and modified under general public license.</p
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