927 resultados para Analysis of Algorithms and Problem Complexity
Resumo:
Genetic markers that distinguish fungal genotypes are important tools for genetic analysis of heterokaryosis and parasexual recombination in fungi. Random amplified polymorphic DNA (RAPD) markers that distinguish two races of biotype B of Colletotrichum gloeosporioides infecting the legume Stylosanthes guianensis were sought. Eighty-five arbitrary oligonucleotide primers were used to generate 895 RAPD bands but only two bands were found to be specifically amplified from DNA of the race 3 isolate. These two RAPD bands were used as DNA probes and hybridised only to DNA of the race 3 isolate. Both RAPD bands hybridised to a dispensable 1.2 Mb chromosome of the race 3 isolate. No other genotype-specific chromosomes or DNA sequences were identified in either the race 2 or race 3 isolates. The RAPD markers hybridised to a 2 Mb chromosome in all races of the genetically distinct biotype A pathogen which infects other species of Stylosanthes as well as S. guianensis. The experiments indicate that RAPD analysis is a potentially useful tool for obtaining genotype-and chromosome-specific DNA probes in closely related isolates of one biotype of this fungal pathogen.
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Two members of the low density lipoprotein receptor (LDLR) family were identified as putative orthologs for a vitellogenin receptor (Amvgr) and a lipophorin receptor (Amlpr) in the Apis mellifera genome. Both receptor sequences have the structural motifs characteristic of LDLR family members and show a high degree of similarity with sequences of other insects. RT-PCR analysis of Amvgr and Amlpr expression detected the presence of both transcripts in different tissues of adult female (ovary, fat body, midgut, head and specifically hypopharyngeal gland), as well as in embryos. In the head RNA samples we found two variant forms of AmLpR: a full length one and a shorter one lacking 29 amino acids in the O-linked sugar domain. In ovaries the expression levels of the two honey bee LDLR members showed opposing trends: whereas Amvgr expression was upregulated as the ovaries became activated, Amlpr transcript levels gradually declined. In situ hybridization analysis performed on ovaries detected Amvgr mRNA exclusively in germ line cells and corroborated the qPCR results showing an increase in Amvgr gene expression concomitant with follicle growth. (C) 2008 Elsevier Ltd. All rights reserved.
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A data warehouse is a data repository which collects and maintains a large amount of data from multiple distributed, autonomous and possibly heterogeneous data sources. Often the data is stored in the form of materialized views in order to provide fast access to the integrated data. One of the most important decisions in designing a data warehouse is the selection of views for materialization. The objective is to select an appropriate set of views that minimizes the total query response time with the constraint that the total maintenance time for these materialized views is within a given bound. This view selection problem is totally different from the view selection problem under the disk space constraint. In this paper the view selection problem under the maintenance time constraint is investigated. Two efficient, heuristic algorithms for the problem are proposed. The key to devising the proposed algorithms is to define good heuristic functions and to reduce the problem to some well-solved optimization problems. As a result, an approximate solution of the known optimization problem will give a feasible solution of the original problem. (C) 2001 Elsevier Science B.V. All rights reserved.
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Objective: The epilepsies associated with the tuberous sclerosis complex (TSC) are very often refractory to medical therapy. Surgery for epilepsy is an effective alternative when the critical link between the localization of seizure onset in the scalp and a particular cortical tuber can be established. In this study we perform analysis of ictal and interictal EEG to improve such link. Methods: The ictal and interictal recordings of four patients with TSC undergoing surgery for epilepsy were submitted to independent component analysis (ICA), followed by source analysis, using the sLORETA algorithm. The localizations obtained for the ictal EEG and for the average interictal spikes were compared. Results: The ICA of ictal EEG produced consistent results in different events, and there was good agreement with the tubers that were successfully removed in three of the four patients (one patient refused surgery). In some patients there was a large discrepancy between the localization of ictal and interictal sources. The interictal activity produced more widespread source localizations. Conclusions: The use of ICA of ictal EEG followed by the use of source analysis methods in four cases of epilepsy and TSC was able to localize the epileptic generators very near the lesions successfully removed in surgery for epilepsy. Significance: The ICA of ictal EEG events may be a useful add-on to the tools used to establish the connection between epileptic scalp activity and the cortical tubers originating it, in patients with TSC considered for surgery of epilepsy.
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Introduction: Les études GVvA (Genome-wide association ,-studies) ont identifié et confirmé plus de 20 gènes de susceptibilité au DT2 et ont contribué à mieux comprendre sa physiopathologie. L'hyperglycémie à jeun (GJ), et 2 heures après une HGPO (G2h) sont les deux mesures cliniques du diagnostic du DT2. Nous avons identifié récemment la G6P du pancréas (G6PC2) comme déterminant de la variabilité physiologique de la GJ puis Ie récepteur à la mélatonine (MTNRIB) qui de plus lie la régulation du rythme circadien au DT2. Dans ce travail nous avons étudié la génétique de la G2h à l'aide de l'approche GWA. Résultats: Nous avons réalisé une méta-analyse GWA dans le cadre de MAGIC (Meta-Analysis of Glucose and Insulin related traits Consortium) qui a inclus 9 études GWA (N=15'234). La réplication de 29 loci (N=6958-30 121, P < 10-5 ) a confirmé 5 nouveaux loci; 2 étant connus comme associés avec Ie DT2 (TCF7L2, P = 1,6 X 10-10 ) et la GJ (GCKR, p = 5,6 X 10-10 ); alors que GIPR (p= 5,2 X 10-12), VSP13C (p= 3,9 X 10-8) et ADCY5 (p = 1,11 X 10-15 ) sont inédits. GIPR code Ie récepteur au GIP (gastric inhibitory polypeptide) qui est sécrété par les ceIlules intestinales pour stimuler la sécrétion de l'insuline en réponse au glucose (l'effet incrétine). Les porteurs du variant GIPR qui augmente la G2h ont également un indice insulinogénique plus bas, (p= 1,0 X 10-17) mais ils ne présentent aucune modification de leur glycémie suite à une hyperglycémie provoquée par voie veineuse (p= 0,21). Ces résultats soutiennent un effet incrétine du locus GIPR qui expliquerait ~9,6 % de la variance total de ce trait. La biologie de ADCY5 et VPS13C et son lien avec l'homéostasie du glucose restent à élucider. GIPR n'est pas associé avec le risque de DT2 indiquant qu'il influence la variabilité physiologique de la G2h alors que le locus ADCY5 est associé avec le DT2 (OR = 1,11, P = 1,5 X 10-15). Conclusion: Notre étude démontre que l'étude de la G2h est une approche efficace d'une part pour la compréhension de la base génétique de la physiologie de ce trait clinique important et d'autre part pour identifier de nouveaux gènes de susceptibilité au DT2.
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The objective of research was to analyse the potential of Normalized Difference Vegetation Index (NDVI) maps from satellite images, yield maps and grapevine fertility and load variables to delineate zones with different wine grape properties for selective harvesting. Two vineyard blocks located in NE Spain (Cabernet Sauvignon and Syrah) were analysed. The NDVI was computed from a Quickbird-2 multi-spectral image at veraison (July 2005). Yield data was acquired by means of a yield monitor during September 2005. Other variables, such as the number of buds, number of shoots, number of wine grape clusters and weight of 100 berries were sampled in a 10 rows × 5 vines pattern and used as input variables, in combination with the NDVI, to define the clusters as alternative to yield maps. Two days prior to the harvesting, grape samples were taken. The analysed variables were probable alcoholic degree, pH of the juice, total acidity, total phenolics, colour, anthocyanins and tannins. The input variables, alone or in combination, were clustered (2 and 3 Clusters) by using the ISODATA algorithm, and an analysis of variance and a multiple rang test were performed. The results show that the zones derived from the NDVI maps are more effective to differentiate grape maturity and quality variables than the zones derived from the yield maps. The inclusion of other grapevine fertility and load variables did not improve the results.
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The distribution of the genus Barbadocladius Cranston & Krosch (Diptera: Chironomidae), previously reported from Chile to Bolivia, has extended northwards. Larvae, pupae and pupal exuviae of this genus have been found in the high mountain tropical streams of Peru to 9°22′56″, but are restricted to very high altitude streams (altitudes over 3,278 m asl) compared to the lower altitude streams (below 1,100 m asl) in which the genus is reported in Chile and Argentina. Based on morphological studies, both described species in the genus, Barbadocladius andinus Cranston & Krosch and Barbadocladius limay Cranston & Krosch, have been found in Peru as pupae or pupal exuviae. Morphological analysis of the larvae and pupae revealed no differences between the two described species from Patagonia and Peru, which are of similar size and with a similar armament of hooklets and spines in pupal tergites and sternites. However, molecular analysis of larvae and pupae revealed that in Peru, there are at least two different evolutionary lines, one distributed widely and another restricted to one site. Phylogenetic analysis (using cox1 mitochondrial sequences) of all available sequences of Barbadocladius shows that the Chilean and Argentinean material differs from that of Peru. Therefore, a total of four molecular segregates are identified, although morphologically, neither larvae nor the pupae may be differentiated.
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Efficient problem solving in cellular networks is important when enhancing the network performance and liability. Analysis of calls and packet switched sessions in protocol level between the network elements is an important part of this process. They can provide very detailed information about error situations which otherwise would be difficult to recognise. In this thesis we seek solutions for monitoring GPRS/EDGE sessions in two specific interfaces simultaneously in such manner that all information important to the users will be provided in easily understandable form. This thesis focuses on Abis and AGPRS interfaces of GSM radio network and introduces a solution for managing the correlation between these interfaces by using signalling messages and common parameters as linking elements. ~: Finally this thesis presents an implementation of GPRS/EDGE session monitoring application for Abis and AGPRS interfaces and evaluates its benefits to the end users. Application is implemented as a part of Windows based 3G/GSM network analyser.
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The design methods and languages targeted to modern System-on-Chip designs are facing tremendous pressure of the ever-increasing complexity, power, and speed requirements. To estimate any of these three metrics, there is a trade-off between accuracy and abstraction level of detail in which a system under design is analyzed. The more detailed the description, the more accurate the simulation will be, but, on the other hand, the more time consuming it will be. Moreover, a designer wants to make decisions as early as possible in the design flow to avoid costly design backtracking. To answer the challenges posed upon System-on-chip designs, this thesis introduces a formal, power aware framework, its development methods, and methods to constraint and analyze power consumption of the system under design. This thesis discusses on power analysis of synchronous and asynchronous systems not forgetting the communication aspects of these systems. The presented framework is built upon the Timed Action System formalism, which offer an environment to analyze and constraint the functional and temporal behavior of the system at high abstraction level. Furthermore, due to the complexity of System-on-Chip designs, the possibility to abstract unnecessary implementation details at higher abstraction levels is an essential part of the introduced design framework. With the encapsulation and abstraction techniques incorporated with the procedure based communication allows a designer to use the presented power aware framework in modeling these large scale systems. The introduced techniques also enable one to subdivide the development of communication and computation into own tasks. This property is taken into account in the power analysis part as well. Furthermore, the presented framework is developed in a way that it can be used throughout the design project. In other words, a designer is able to model and analyze systems from an abstract specification down to an implementable specification.
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The aim of this study is to investigate the floristic composition of an Atlantic rain forest fragment located in Cananéia, São Paulo, Brazil, and to contribute to the knowledge on Atlantic forest through the comparative analysis of this and other floristic surveys both on the southern and southeastern Brazil, in different soil and relief types. We surveyed 215 species in 132 genera and 51 families. Classification and ordination analysis were applied to a binary matrix in order to analyze the similarity among 24 surveys, including the present one, of Atlantic forest from the south and southeast coast of Brazil. Higher floristic similarity was observed among this area and the ones where there was marine influence and more rugged relief. The surveys in areas with greater marine influence (sandy soil) were separated from those in other conditions, possibly indicating a species replacement gradient from the steep slopes towards the lowland and were probably related to different edaphic conditions. A latitudinal gradient was found among the surveys apparently confirming a continuous species replacement along the Atlantic forest, related to a restricted distribution of the species. This suggests that it is essential to preserve areas from the whole Atlantic coast. Atlantic forest distribution is quite complex and its composition cannot be adequately represented by small localized areas.
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(Morphological cladistic analysis of Pseudobombax Dugand (Malvaceae, Bombacoideae) and allied genera). Pseudobombax Dugand belongs to the family Malvaceae subfamily Bombacoideae and aggregates 29 species restricted to the Neotropics. A morphological cladistic analysis of Pseudobombax and allied genera was carried out to test the monophyly of the genus and to provide hypotheses on its phylogeny. Parsimony analyses were based on 40 morphological characters and 28 species, 14 belonging to Pseudobombax and 14 to other species of Bombacoideae, Matisieae (Malvoideae) and Ochromeae. Nine most parsimonious trees (144 steps, ci 0.40, ri 0.67) were produced when 10 multistate characters were taken as ordered while only two most parsimonious trees (139 steps, ci 0.41, ri 0.67) were obtained when all characters were considered as unordered. Pseudobombax monophyly had moderate bootstrap support, appearing as sister to a clade composed of the genera Bombacopsis Pittier and Pachira Aubl., or to the genus Bombax L. according to the analysis. The petiole widened at the apex and the leaflets not jointed to the petiole are probably synapomorphies of Pseudobombax. Three main clades were found in the genus: one characterised by petiolulated leaflets and 5-angular fruits, the other by pubescent leaves and calyx, and the other by reduction of the number of leaflets. The latter includes species endemic to the Brazilian semi-arid region also characterised by the absence of phalanges in the androecium. Interspecific affinities in Pseudobombax as well as the morphological evolution in Bombacoideae are discussed.
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Hydrogeological research usually includes some statistical studies devised to elucidate mean background state, characterise relationships among different hydrochemical parameters, and show the influence of human activities. These goals are achieved either by means of a statistical approach or by mixing models between end-members. Compositional data analysis has proved to be effective with the first approach, but there is no commonly accepted solution to the end-member problem in a compositional framework. We present here a possible solution based on factor analysis of compositions illustrated with a case study. We find two factors on the compositional bi-plot fitting two non-centered orthogonal axes to the most representative variables. Each one of these axes defines a subcomposition, grouping those variables that lay nearest to it. With each subcomposition a log-contrast is computed and rewritten as an equilibrium equation. These two factors can be interpreted as the isometric log-ratio coordinates (ilr) of three hidden components, that can be plotted in a ternary diagram. These hidden components might be interpreted as end-members. We have analysed 14 molarities in 31 sampling stations all along the Llobregat River and its tributaries, with a monthly measure during two years. We have obtained a bi-plot with a 57% of explained total variance, from which we have extracted two factors: factor G, reflecting geological background enhanced by potash mining; and factor A, essentially controlled by urban and/or farming wastewater. Graphical representation of these two factors allows us to identify three extreme samples, corresponding to pristine waters, potash mining influence and urban sewage influence. To confirm this, we have available analysis of diffused and widespread point sources identified in the area: springs, potash mining lixiviates, sewage, and fertilisers. Each one of these sources shows a clear link with one of the extreme samples, except fertilisers due to the heterogeneity of their composition. This approach is a useful tool to distinguish end-members, and characterise them, an issue generally difficult to solve. It is worth note that the end-member composition cannot be fully estimated but only characterised through log-ratio relationships among components. Moreover, the influence of each endmember in a given sample must be evaluated in relative terms of the other samples. These limitations are intrinsic to the relative nature of compositional data
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Genetic parameters and breeding values for dairy cow fertility were estimated from 62 443 lactation records. Two-trait analysis of fertility and milk yield was investigated as a method to estimate fertility breeding values when culling or selection based on milk yield in early lactation determines presence or absence of fertility observations in later lactations. Fertility traits were calving interval, intervals from calving to first service, calving to conception and first to last service, conception success to first service and number of services per conception. Milk production traits were 305-day milk, fat and protein yield. For fertility traits, range of estimates of heritability (h(2)) was 0.012 to 0.028 and of permanent environmental variance (c(2)) was 0.016 to 0.032. Genetic correlations (r(g)) among fertility traits were generally high ( > 0.70). Genetic correlations of fertility with milk production traits were unfavourable (range -0.11 to 0.46). Single and two-trait analyses of fertility were compared using the same data set. The estimates of h(2) and c(2) were similar for two types of analyses. However, there were differences between estimated breeding values and rankings for the same trait from single versus multi-trait analyses. The range for rank correlation was 0.69-0.83 for all animals in the pedigree and 0.89-0.96 for sires with more than 25 daughters. As single-trait method is biased due to selection on milk yield, a multi-trait evaluation of fertility with milk yield is recommended. (C) 2002 Elsevier Science B.V. All rights reserved.
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Elephant poaching and the ivory trade remain high on the agenda at meetings of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Well-informed debates require robust estimates of trends, the spatial distribution of poaching, and drivers of poaching. We present an analysis of trends and drivers of an indicator of elephant poaching of all elephant species. The site-based monitoring system known as Monitoring the Illegal Killing of Elephants (MIKE), set up by the 10th Conference of the Parties of CITES in 1997, produces carcass encounter data reported mainly by anti-poaching patrols. Data analyzed were site by year totals of 6,337 carcasses from 66 sites in Africa and Asia from 2002–2009. Analysis of these observational data is a serious challenge to traditional statistical methods because of the opportunistic and non-random nature of patrols, and the heterogeneity across sites. Adopting a Bayesian hierarchical modeling approach, we used the proportion of carcasses that were illegally killed (PIKE) as a poaching index, to estimate the trend and the effects of site- and country-level factors associated with poaching. Important drivers of illegal killing that emerged at country level were poor governance and low levels of human development, and at site level, forest cover and area of the site in regions where human population density is low. After a drop from 2002, PIKE remained fairly constant from 2003 until 2006, after which it increased until 2008. The results for 2009 indicate a decline. Sites with PIKE ranging from the lowest to the highest were identified. The results of the analysis provide a sound information base for scientific evidence-based decision making in the CITES process.
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Abstract: During the transition from endo-dormancy to eco-dormancy and subsequent growth, the onion bulb undergoes the transition from sink organ to source, to sustain cell division in the meristematic tissue. The mechanisms controlling these processes are not fully understood. Here, a detailed analysis of whole onion bulb physiological, biochemical and transcriptional changes in response to sprouting is reported, enabling a better knowledge of the mechanisms regulating post-harvest onion sprout development. Biochemical and physiological analyses were conducted on different cultivars ('Wellington', 'Sherpa' and 'Red Baron') grown at different sites over 3 years, cured at different temperatures (20, 24 and 28 degrees C) and stored under different regimes (1, 3, 6 and 6 1 degrees C). In addition, the first onion oligonucleotide microarray was developed to determine differential gene expression in onion during curing and storage, so that transcriptional changes could support biochemical and physiological analyses. There were greater transcriptional differences between samples at harvest and before sprouting than between the samples taken before and after sprouting, with some significant changes occurring during the relatively short curing period. These changes are likely to represent the transition from endo-dormancy to sprout suppression, and suggest that endo-dormancy is a relatively short period ending just after curing. Principal component analysis of biochemical and physiological data identified the ratio of monosaccharides (fructose and glucose) to disaccharide (sucrose), along with the concentration of zeatin riboside, as important factors in discriminating between sprouting and pre-sprouting bulbs. These detailed analyses provide novel insights into key regulatory triggers for sprout dormancy release in onion bulbs and provide the potential for the development of biochemical or transcriptional markers for sprout initiation. Evidence presented herein also suggests there is no detrimental effect on bulb storage life and quality caused by curing at 20 degrees C, producing a considerable saving in energy and costs.