Dissertations / Theses on the topic 'Weight matrix'

Alumina particles filled Ultra-high Molecular Weight Polyethylene (UHMWPE), with Al2O3 contents 0, 1, and 2.5 wt% were milled for up to 10 hours by the mechanical alloying (MA) process performed at room temperature to produce composite powders. Compression molding was utilized to produce sheets out of the milled powders. A partial phase transformation from orthorhombic and amorphous phases to monoclinic phase was observed to occur for both the un-reinforced and reinforced UHMWPE in the solid state, which disappeared after using compression molding to produce composite sheets. The volume fraction of the monoclinic phase increased with milling time, mostly at the expense of the amorphous phase. The melting temperature decreased as a function of milling time as a result of modifications in the UHMWPE molecular structure caused by the milling. At the same time, for a given alumina composition the activation energy of melting increased with milling time. Generally, the crystallinity of the molded sheets increased with milling time, and this caused the yield strength and elastic modulus to increase with milling time for a given alumina composition. However, the tensile strength and ductility remained about the same.
Master of Science

Lagringskapaciteten i ett litet spiking Hopfieldnätverk undersöks med hjälp av två parametrar som styr resistansen och inhibitionen hos de synaptiska kopplingarna. Det är motiverat av möjligheten att skapa större associativa nätverk från små nätverkskluster. Den här typen av nätverksarkitekturer har observerats i naturen och skulle kunna vara grunden till framtida applikationer. Undersökningen är genomförd med hjälp av simulatorer, neuronmodeller av typen integrate-and-fire och statiska synapser. Flera olika typer av binäramönster används för att ge en detaljerad analys av lagringskapaciteten. De undersökta parametrarna har inverkan på lagringskapaciteten hosnätverket. Även skillnader i kapacitet mellan olika mönster är observerat.
The storage capacity of a small spiking Hopfield network is investigated in terms of two parameters governing the conductance and inhibition of the synaptic connections. This is motivated by the possibility of constructing larger associative networks from small network clusters. These kinds of network architectures have been observed in nature and could possibly be a foundation for future applications. The investigation is conducted using simulations of integrate-and-fire neuron models and static synapses. Several different types of binary patterns are used to provide a detailed analysis of the storage capacity. The investigated parameters have influence on the storage capacity of the network and the capacity may be improved with the right choice of parameters. Also, differences in capacity for different pattern types are observed.

Aluminum metal-matrix composites (MMCs) are well positioned to replace steel in numerous manufactured structural components, due to their high strength-to-weight and stiffness ratios. For example, research is currently being conducted in the use of such materials in the construction of tank entry doors, which are currently made of steel and are dangerously heavy for military personnel to lift and close. However, the manufacture of aluminum MMCs is inefficient in many cases due to the loss of material through edge cracking during the hot rolling process which is applied to reduce thick billets of as-cast material to usable sheets. In the current work, mechanical characterization and numerical modeling of as-cast aluminum A359-SiCsubscript p]-30% is employed to determine the properties of the composite and identify their dependence on strain rate and temperature conditions. Tensile and torsion tests were performed at a variety of strain rates and temperatures. Data obtained from tensile tests were used to calibrate the parameters of a material model for the composite. The material model was implemented in the ANSYS finite element software suite, and simulations were performed to test the ability of the model to capture the mechanical response of the composite under simulated tension and torsion tests. A temperature- and strain rate-dependent damage model extended the constitutive model to capture the dependence of material failure on testing or service conditions. Several trends in the mechanical response were identified through analysis of the dependence of experimentally-obtained material properties on temperature and strain rate. The numerical model was found to adequately capture strain rate and temperature dependence of the stress-strain curves in most cases.; Ductility modeling allowed prediction of stress and strain conditions which would lead to rupture, as well as identification of areas of a solid model which are most likely to fail under a given set of environmental and load conditions.
ID: 030423478; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.M.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 113-118).
M.S.
Masters
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science

The effect of molecular weight on the dispersion of relatively polar montmorillonite (MMT) in non polar, unmodified high density polyethylene (HDPE) was examined. Polymer layered silicate (PLS) nanocomposites were compounded using three unmodified HDPE matrices of differing molecular weight and an organically modified MMT in concentrations ranging from 2 wt% to 8 wt% via single screw extrusion. The weight average molecular weights of the HDPE matrices used in this study ranged from 87,000 g/mol to 460,000 g/mol. X-ray diffraction (XRD), mechanical testing, dynamic mechanical thermal analysis (DMTA), as well as dynamic and capillary rheometry were performed on the nanocomposites. Nanocomposites generated from the high molecular weight (HMW) HDPE matrix exhibited increased intercalation of the MMT as shown by XRD as well as greater improvements in the Youngâ s modulus compared to nanocomposites generated from both the low (LMW) and middle molecular weight (MMW) matrices. This was attributed to higher shear stress imparted to MMT during compounding from the more viscous matrix facilitating their separation and orientation during injection molding. DMTA showed that the torsional response of the HMW nanocomposites was not as great compared to their LMW and MMW counterparts as observed from a lower percentage enhancement in the storage modulus (Gâ ) and estimated heat distortion temperature (HDT) due to anisotropy in mechanical properties. Dynamic rheology indicated that a percolated network did not exist in any of the nanocomposites as shown by no change in the terminal behavior of Gâ upon addition of clay.
Master of Science

Soft-landing ion mobility has applicability in a variety of areas. The ability to produce material and collect a sufficient amount for further analysis and applications is the key goal of this technique. Soft-landing ion mobility has provided a way to deposit material in a controllable fashion, and can be tailored to specific applications. Changing the conditions at which soft-landing ion mobility occurs effects the characteristics of the resulting particles (size, distribution/coverage on the surface). Longer deposition times generated more material on the surface; however, higher pressures increased material loss due to diffusion. Larger particles were landed when using higher pressures, and increased laser energy at ablation. The utilization of this technique for the deposition of silver clusters has provided a solvent free matrix application technique for MALDI-MS. The low kinetic energy of incident ions along with the solvent free nature of soft-landing ion mobility lead to a technique capable of imaging sensitive samples and low mass analysis. The lack of significant interference as seen by traditional organic matrices is avoided with the use of metallic particles, providing a major enhancement in the ability to analyze low mass compounds by MALDI.

This paper considers the problem of model uncertainty associated with variable selection and specification of the spatial weight matrix in spatial growth regression models in general and growth regression models based on the matrix exponential spatial specification in particular. A natural solution, supported by formal probabilistic reasoning, is the use of Bayesian model averaging which assigns probabilities on the model space and deals with model uncertainty by mixing over models, using the posterior model probabilities as weights. This paper proposes to adopt Bayesian information criterion model weights since they have computational advantages over fully Bayesian model weights. The approach is illustrated for both identifying model covariates and unveiling spatial structures present in pan-European growth data. (authors' abstract)
Series: Department of Economics Working Paper Series

In this study, for the well-known Analytic Hierarchy Process (AHP) method a new approach to interval priority weight generation from interval comparison matrix is proposed. This method can be used for both inconsistent and consistent matrices. Also for the problems having more than two hierarchical levels a synthesizing heuristic is presented. The performances of the methods, interval generation and synthesizing, are compared with the methods that are already available in the literature on randomly generated matrices.

Transcription factor (TF) binding has been studied extensively in relation to binding site affinity and chromosome modifications; however, the relationship between genome spatial organisation and transcription factor binding is not well studied. Using the recently available high resolution Hi-C contact map of human GM12878 lymphoblastoid cells, we investigated computationally the genome-wide spatial co-localization of transcription factor binding sites, for both within the same type and between different types. First, we observed a strong positive correlation between site occupancy and homotypic TF co-localization based on Hi-C contacts, consistent with our predictions from biophysical simulations of TF target search. This trend is more prominent in binding sites with weak binding sequences and within enhancers, suggesting genome spatial organisation plays an essential role in determining binding site occupancy, especially for weak regulatory elements. Furthermore, when investigating spatial co-localization between different TFs, we discovered two distinct co-localization networks of TFs in lymphoblastoid cells, one of which is enriched in lymphocyte specific pathways and distal enhancer binding. These two TF networks have strong biases for either the A1 or A2 chromosome subcompartment, but nonetheless are still preserved within each, indicating a potential causal link between cell-type-specific transcription factor binding and chromosome subcompartment segregation. We called 40 pairs of significantly co-localized TFs according to the genome wide Hi-C contact map, which are enriched in previously reported, physical interactions, thus linking TF spatial network to co-functioning. In addition to the above main project, I also worked on a side project to find compute-efficient ways in scaling binding site strength across different TFs based on Position-Weight-Matrices (PWM). While common bioinformatics tools produce scores that can reflect the binding strength between a specific TF and the DNA, these scores are not directly comparable between different TFs. We provided two approaches in estimating a scaling parameter $\lambda$ to the PWM score for different TFs. The first approach uses a PWM and background genomic sequence as input to estimate $\lambda$ for a specific TF, which we applied to show that $\lambda$ distributions for different TF families correspond with their DNA binding properties. Our second method can reliably convert $\lambda$ between different PWMs of the same TF, which allows us to directly compare PWMs that were generated by different approaches.

Mixed matrix membranes (MMMs) have gained importance because they combine the desirable properties of the polymers and the organic/inorganic filler materials and they may have a very big potential. In this study polyethersulfone (PES) was used as polymeric material, and Zeolitic Imidazolate Framework-8 (ZIF-8) was used as porous filler material, and 2-hydroxy 5-methyl aniline(HMA), was used as a third component in membrane formulation. In this study, ZIF-8 crystals were synthesized with varying particle sizes, and a novel recycling methodology was developed to improve the efficiency of ZIF-8 production. ZIF-8 nano-crystals were synthesized by a 1-hour stirring method at room temperature and characterized by X-ray diffractometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and thermal gravimetric analysis (TGA). In order to investigate the effect of ZIF-8 loading on the membrane performance, different types of membranes were prepared with varying amounts of ZIF-8 between 10-60% (w/w). Moreover, ternary mixed matrix membranes were synthesized consisting of different amounts of ZIF-8 between 10-30% (w/w) and HMA 1-10% (w/w). Gas transport properties of the membranes were investigated by single gas permeation experiments of H2, CO2 and CH4 at 3 bar feed pressure. In order to investigate the effect of feed pressure on the gas transport properties of the membranes, single gas experiments were conducted on 3, 6, 8, 10 and 12 bar feed pressures. Moreover, binary gas permeation experiments of CO2/CH4 pair were conducted through selected membranes at 3 bar and 12 bar feed pressures. In addition to gas permeation experiments, the morphology and thermal characteristics of the membranes were characterized by SEM, TGA and differential scanning calorimetry (DSC) analysis. The incorporation of ZIF-8 crystals into continuous PES matrix resulted in high performance gas separation membranes. The permeabilities of all studied gases increased with ZIF-8 loading while the ideal selectivities showed a slight decrease compared to neat PES membrane. Highly reproducible and repeatable results were obtained up to 30 % w/w ZIF-8 loading, while membrane formulation reproducibility was decreased for higher ZIF-8 contents (>
30 w/w %). Addition of HMA improved the gas separation performances of the binary membranes significantly by decreasing permeabilities and increasing ideal selectivities. PES/ZIF-8(%20)/HMA(%7) membrane has the best separation performance for all gases among the ternary membranes. When 7 w/w % HMA was added to PES/ZIF-8(%20) membrane, H2 permeability decreased from 26.3 to 13.7 barrer, while H2/CH4 ideal selectivity increased from 61.8 to 103.7. Increasing feed pressures appreciably increased the separation performances of all membranes. While the H2 permeability is pressure independent, the CO2 and CH4 permeabilities were reduced with increasing feed pressures and the highest selectivity improvement was observed in H2/CH4 pair for all membrane compositions. For instance, when the feed pressure was increased from 3 bar to 12 bar, the percentage improvements in ideal selectivities through PES/ZIF-8(%10)/HMA(%4) membrane were calculated as 26, 69, 113 % for the H2/CO2, CO2/CH4 and H2/CH4 gas pairs
respectively. This results show that working at higher feed pressures will be more advantageous for separation of the studied gas pairs. The ideal selectivities and the separation factors were equal to each other for all membrane compositions both for 3 and 12 bar operating pressures.

Flash is the unwanted or excessrubber material that presents on the outersurface of themolded rubber product. This will affect the surface finish; it is a cosmetic defect andit can be removed. It forms because of the leak or the excess molded rubber materialbetween the surface of the mold, typically on the parting line, (Jordan Anderson,2014). The presence of flash will reduce customer satisfaction. There are manymethods to remove the flash. The method is selected according to the degree of flashextension and the location where it occurs.The project aims to design a semi/full automated machine, which helps for having asmooth and fine surface finish of the weight plates. These plates are made up of rubberfor the ELEIKO group. The weight plates have different weights from 10 to 20 kg,but the diameter of each plate stays the same, but the thickness will be different foreach plate. The machine should be designed that removes all the excess rubber andshould smoothen the outer surface of the weight. The purpose of this work is to gainknowledge about different product development methods, respective tools, andtechniques that are used. The machine should be user- friendly, should not becomplicated, should not damage the workpiece (marks or trace of the blade), shouldnot put the employer in danger, and economically feasible.This report presents the progress of designing of the product, product development,methods, and literature study. The designed model can construct in the industry fortheir problem they are faced by the flash. The model is very simple and unique so thateveryone can perform the task without any previous experience. Material alternativeswere evaluated as well as manufacturing possibilities. The designed machine was theoffered for free as means for further research and development. Keywords: flashing, additive manufacturing, Ullman method, Pugh matrix, rubberweight plates, lever arm, smoothening tool.

O presente trabalho implementa a otimização dos ganhos de um controle ativo com regulador linear quadrático (LQR), em um modelo veicular completo sujeito a um perfil de estrada proposto pela ISO 8608, para atenuação das acelerações RMS transmitidas para a carroceria e o assento do motorista. Dado que o ganho do controle LQR é formulado a partir das matrizes Q e R, o procedimento determina as matrizes ótimas do controle para a minimização das acelerações RMS transmitidas. O modelo é analisado no domínio do tempo por meio da formulação de espaço-estado, e o procedimento de otimização é avaliado pelo método dos algoritmos genéticos. Os parâmetros Q e R, que fornecem o melhor ganho para minimização do problema de otimização, reduzem em até 1000 vezes as acelerações RMS quando comparadas à situação sem atuação do controle. Após otimizar Q e R, são analisadas a influência nos demais graus de liberdade e as forças necessárias para os resultados obtidos.
This work aims to optimize the gains of an active control with linear quadratic regulator (LQR), applied in a full vehicle model subject to a random road surface profile proposed by ISO 8608, for reduction of RMS accelerations transmitted to the driver’s seat and the vehicle body. Since the gain of LQR control is formulated from the matrices Q and R, the procedure determines the optimal control matrices that minimize the RMS accelerations transmitted. The model is analyzed in the time domain through state-space formulation, and the optimization process evaluated by the method of genetic algorithms. The parameters Q and R, which provide the best gain for minimizing the optimization problem, reduce by up to 1000 times the RMS accelerations when compared to the situation without active control. Finally, after optimizing Q e R, are analyzed the influence to the other degrees of freedom and the forces necessary for the results obtained.

Markov-type inequalities provide upper bounds on the norm of the (higher order) derivative of an algebraic polynomial in terms of the norm of the polynomial itself. The present thesis considers the cases in which the norms are of the Laguerre, Gegenbauer, or Hermite type, with respective weights chosen differently on both sides of the inequality. An answer is given to the question on the best constant so that such an inequality is valid for every polynomial of degree at most n. The demanded best constant turns out to be the operator norm of the differential operator. The latter conicides with the tractable spectral norm of its matrix representation in an appropriate set of orthonormal bases. The methods to determine these norms vary tremendously, depending on the difference of the parameters accompanying the weights. Up to a very small gap in the parameter range, asymptotics for the best constant in each of the aforementioned cases are given
Markovungleichungen liefern obere Schranken an die Norm einer (höheren) Ableitung eines algebraischen Polynoms in Bezug auf die Norm des Polynoms selbst. Diese vorliegende Arbeit betrachtet den Fall, dass die Normen vom Laguerre-, Gegenbauer- oder Hermitetyp sind, wobei die entsprechenden Gewichte auf beiden Seiten unterschiedlich gewählt werden. Es wird die kleinste Konstante bestimmt, sodass diese Ungleichung für jedes Polynom vom Grad höchstens n erfüllt ist. Die gesuchte kleinste Konstante kann als die Operatornorm des Differentialoperators dargestellt werden. Diese fällt aber mit der Spektralnorm der Matrixdarstellung in einem Paar geeignet gewählter Orthonormalbasen zusammen und kann daher gut behandelt werden. Zur Abschätzung dieser Normen kommen verschiedene Methoden zum Einsatz, die durch die Differenz der in den Gewichten auftretenden Parameter bestimmt werden. Bis auch eine kleine Lücke im Parameterbereich wird das asymptotische Verhalten der kleinsten Konstanten in jedem der betrachteten Fälle ermittelt

In a large population-based study among adults in northern Europe the relation between occupational exposure and new-onset asthma was studied. The study comprised 13 284 subjects born between 1945 and 1973, who answered a questionnaire 19891992 and again 19992001. Asthma was defined as Asthma diagnosed by a physician with reported year of diagnose. Hazard ratios (HR), for new-onset adult asthma during 19802000, were calculated using a modified job-exposure matrix as well as high-risk occupations in Cox regression models. The analyses were made separately for men and women and were also stratified for atopy. During the observation period there were 429 subjects with new-onset asthma with an asthma incidence of 1.3 cases per 1000 person-years for men and 2.4 for women. A significant increase in new-onset asthma was seen for men exposed to plant-associated antigens (HR 3.6; 95% CI [confidence interval] 1.49.0), epoxy (HR 2.4; 95% CI 1.34.5), diisocyanates (HR 2.1; 95% CI 1.23.7) and accidental peak exposures to irritants (HR 2.4; 95% CI 1.34.7). Both men and women exposed to cleaning agents had an increased asthma risk. When stratifying for atopy an increased asthma risk were seen in non-atopic men exposed to acrylates (HR 3.3; 95% CI 1.47.5), epoxy compounds (HR 3.6; 95% CI 1.67.9), diisocyanates and accidental peak exposures to irritants (HR 3.0; 95% CI 1.27.2). Population attributable risk for occupational asthma was 14% for men and 7% for women. This population-based study showed that men exposed to epoxy, diisocyanates and acrylates had an increased risk of new-onset asthma. Non-atopics seemed to be at higher risk than atopics, except for exposure to high molecular weight agents. Increased asthma risks among cleaners, spray painters, plumbers, and hairdressers were confirmed.

Markov-type inequalities provide upper bounds on the norm of the (higher order) derivative of an algebraic polynomial in terms of the norm of the polynomial itself. The present thesis considers the cases in which the norms are of the Laguerre, Gegenbauer, or Hermite type, with respective weights chosen differently on both sides of the inequality. An answer is given to the question on the best constant so that such an inequality is valid for every polynomial of degree at most n. The demanded best constant turns out to be the operator norm of the differential operator. The latter conicides with the tractable spectral norm of its matrix representation in an appropriate set of orthonormal bases. The methods to determine these norms vary tremendously, depending on the difference of the parameters accompanying the weights. Up to a very small gap in the parameter range, asymptotics for the best constant in each of the aforementioned cases are given.
Markovungleichungen liefern obere Schranken an die Norm einer (höheren) Ableitung eines algebraischen Polynoms in Bezug auf die Norm des Polynoms selbst. Diese vorliegende Arbeit betrachtet den Fall, dass die Normen vom Laguerre-, Gegenbauer- oder Hermitetyp sind, wobei die entsprechenden Gewichte auf beiden Seiten unterschiedlich gewählt werden. Es wird die kleinste Konstante bestimmt, sodass diese Ungleichung für jedes Polynom vom Grad höchstens n erfüllt ist. Die gesuchte kleinste Konstante kann als die Operatornorm des Differentialoperators dargestellt werden. Diese fällt aber mit der Spektralnorm der Matrixdarstellung in einem Paar geeignet gewählter Orthonormalbasen zusammen und kann daher gut behandelt werden. Zur Abschätzung dieser Normen kommen verschiedene Methoden zum Einsatz, die durch die Differenz der in den Gewichten auftretenden Parameter bestimmt werden. Bis auch eine kleine Lücke im Parameterbereich wird das asymptotische Verhalten der kleinsten Konstanten in jedem der betrachteten Fälle ermittelt.

Les packagings d’électronique embarquée sont actuellement en alliages d’aluminium. A partir d’une étude de sélection des matériaux, complétée par une simulation numérique thermique,nous avons démontré qu’un matériau composite constitué d’une matrice aluminium et de fibres de carbone à forte conductivité thermique, représente un fort potentiel de gain de masse sur ces équipements. Cependant, le couplage de ces deux matériaux génère des problèmes d’élaboration en raison d’incompatibilités fortes parmi lesquelles un mouillage très faible du carbone par l’aluminium liquide et une réactivité chimique élevée qui conduit à la formation de carbures d’aluminium préjudiciables pour le matériau final. Deux voies d’élaboration distinctes ont été envisagées : Une voie liquide où l’utilisation d’un agent de mouillage (un sel fluoré) a permis d’obtenir la montée par capillarité du métal dans des mèches de fibres. Une voie solide basée sur une technique originale d’empilements de feuillets d’aluminium et de fibres de carbone avec le procédé de Spark Plasma Sintering (SPS). .La seconde technique s’est révélée prometteuse en permettant d’obtenir des échantillons multicouches sans porosités, un endommagement très limité des fibres et une architecture contrôlée.Notre étude a montré que la formation de carbures d’aluminium est limitée. De plus, une meilleure compréhension du SPS ou l’application d’un revêtement sur les fibres devraient permettre d’éviter la formation de ces carbures. Les tentatives de caractérisations mécanique et thermique effectuées sur ces échantillons donnent un premier aperçu de l’efficacité du renforcement de l’aluminium par les fibres de carbone
Embedded electronic packagings are currently made of aluminum. A first study – basedupon a material selection method completed by numerical analysis – showed that a metal matrixcomposite made of aluminum and highly thermal conductive continuous carbon fibers represents ahigh potential upon weight savings for those equipments. Though, coupling these componentsrepresents numerous challenges due to their incompatibility such as a really low wetting of carbonliquidaluminum system and its unavoidable chemical reactivity that leads to the formation ofaluminum carbides that are harmful for the final material. Two manufacturing routes were considered: A liquid route using a wetting agent (fluorinated salts) led the metal to rise alongcarbon fibers by capillarity. A solid route based upon a novel technique of aluminum foils and carbon fibersstacking using the Spark Plasma Sintering (SPS) process.This second technique revealed to be very promising and allowed to obtain multilayer samples with noporosities, highly limited fiber damages and controlled composite architecture. Our study shows thataluminum carbides formation is limited. Moreover, a deeper comprehension of SPS process or thedeposit of fiber coatings would prevent this carbide formation. Attempts of mechanical and thermalcharacterization led upon such samples give a first overview of the efficiency of the aluminumreinforcement by carbon fibers

Spatial econometrics can bring a useful approach to macroeconomic analysis of regional data. This thesis delineates suitable cross-section data models regarding their geographical location. Neighbourhood relation is used for the analysis. The relation of neighbourhood among the regions is expressed using spatial weight matrix. We focus on spatial autocorrelation tests and introduce processes of finding a suitable spatial model. Further, we describe regression coefficients estimates and estimates of spatial dependence coefficients, especially method of maximum likelihood estimates. Besides illustrative examples we apply chosen basic spatial models on real macroeconomic data. We examine how they describe relation between household incomes, GDP and unemployment rate in western Europe. Results are compared with a linear regression model.

This thesis gives a comprehensive characterization of lightweight non-oxide ceramic materials for ballistic applications, an overview of production technologies and processing of boron carbide B4C and its ceramic-based composites. A framework for evaluating the ballistic resistance of the material based on mechanical properties is shown there. It can be used in experiments without normalized equipment. The experiments including B4C + Si, B4C + Ti composites, and application of Spark plasma sintering (SPS) were designed according to outputs from the theoretical part. The volume fractions of Si, Ti dopants were optimized based on ongoing chemical reactions during sintering. The obtained samples were subjects of mechanical testing which results were compared to identify the ideal ratio of matrix and reinforcement. As the best suited material for ballistic protection, B4C + 1,0 obj. % reaches these values of parameters; hardness = 3502 ± 122 HV1; fracture toughness KIC = 2,97 ± 0,03 MPam^0,5.

La réparation de lésions cérébrales reste de nos jours un grand challenge de l'ingénierie tissulaire. De même, l'établissement de modèles in vitro représentatifs du tissu cérébral est un sujet qu'il reste à explorer, surtout du point de vue des biomatériaux à utiliser pour soutenir la croissance cellulaire. Ce travail consiste donc au développement d'un biomatériau de type hydrogel adapté à la survie et la croissance de cellules souches neurales humaines. Les gels de type (supra)moléculaires, qui ont la particularité de se former par auto-assemblage, pourraient présenter de nombreux avantages pour ce type d'application. En effet, ils possèdent entre autres des propriétés mécaniques, une biodisponibilité et une structuration aux échelles micro et nanométriques originale qui font de ces gels des supports intéressants pour la culture de neurones. Une famille de gélifiants supramoléculaires a donc été synthétisée, caractérisée et étudiée en tant que support de culture cellulaire. Ces gélifiants sont de type alkylgalactonamide, c'est-à-dire dérivés d'un sucre - le galactose - et d'une chaîne grasse de type alkyle. Ils forment des hydrogels par refroidissement jusqu'à température ambiante d'une solution de gélifiant préalablement portée à haute température. Le refroidissement entraîne la formation de fibres micrométriques par auto-assemblage des molécules. Il a été établi qu'un contrôle précis du refroidissement lors de leur préparation permettait l'obtention d'hydrogels plus homogènes, plus résistants, qui sont compatibles avec les conditions de culture cellulaire et avec des fibres plus longues. Ces hydrogels se sont révélés être biocompatibles, avec une survie et une croissance en trois dimensions des cellules souches neurales humaines en leur sein. Ces dernières développent de longs neurites et expriment des marqueurs de la différentiation neuronale (ß3-tubuline) ou gliale (GFAP), notamment sur l'un des hydrogels. Le dernier aspect de ce travail a consisté à l'utilisation de nouvelles techniques de structuration en 3D des matériaux afin de construire avec ces hydrogels des supports centimétriques avec une forme bien définie. Une technique de filage en voie humide basée sur l'échange de solvants (wet spinning) a alors été mise au point permettant d'extruder l'hydrogel de façon contrôlée et directement à température ambiante. Elle permet d'obtenir de fins filaments de gel très réguliers soutenus par des fibres nanométriques de largeur monodispersée. Des essais ont également été effectués pour appliquer cette technique à l'impression 3D. Au final, ce projet démontre que certains gels moléculaires peuvent présenter des propriétés particulièrement adaptées pour l'ingénierie tissulaire notamment avec des cellules souches neurales et ouvrent également des perspectives dans le domaine de la mise en forme de ces matériaux délicats
Nowadays, repairing brain lesions is still one of the main challenges of tissue engineering. Meanwhile, work still has to be done for the creation of representative in vitro brain tissue models, especially when it comes to the biomaterials used to support cell growth. This present work consists in the development of a hydrogel as a biomaterial for the survival and growth of human neural stem cells. These (supra)molecular gels, the property of which is to form by self-assembly, may present many advantages for this kind of application. Indeed, their mechanical properties, their bioavailability and their microstructure - among others - make them interesting candidates for neuron culture. One family of supramolecular gelators have thus been synthesized, characterized and tested as cell culture scaffolds. Those gelators are alkylgalactonamides, which means they are derived from a sugar - the galactose - and an alkyl fatty chain. They form hydrogels by cooling down to room temperature after a first dissolution at high temperature. The cooling provokes the self-assembly of the molecules resulting in the formation of the fibers. During their preparation, it has been found that a controlled cooling rate enabled the formation of more homogeneous and more stable hydrogels that are compatible with cell culture conditions and with longer fibers. These hydrogels have shown a good biocompatibility as well as a good cell survival and a three-dimensional growth of human neural stem cells. The latter grew long neurites and expressed markers of neuronal (ß3-tubulin) and glial differentiation (GFAP), especially on one of the hydrogels. The last part of this work was to use new 3D material structuring techniques in order to further construct well-defined centimetric scaffolds with these hydrogels. A technique of wet spinning based on solvent exchange was developed and enabled the direct and controlled extrusion of the hydrogel at room temperature. Thin and regular hydrogel filaments composed of monodisperse nanometric fibers can thus be obtained. Trials have also been done to apply this method to 3D printing. In the end, this project shows that some molecular gels can display properties particularly adapted for tissue engineering, especially with neural stem cells, and it also opens perspectives for the shaping of these delicate materials

Design problems involve finding optimal plans that minimize cost and maximize information about the effects of changing experimental variables on some response. Information is typically measured through statistically meaningful functions, or criteria, of a design's corresponding information matrix. The most common criteria implicitly assume equal interest in all effects and certain forms of information matrices tend to optimize them. However, these criteria can be poor assessments of a design when there is unequal interest in the experimental effects. Morgan and Wang (2010) addressed this potential pitfall by developing a concise weighting system based on quadratic forms of a diagonal matrix W that allows a researcher to specify relative importance of information for any effects. They were then able to generate a broad class of weighted optimality criteria that evaluate a design's ability to maximize the weighted information, ultimately targeting those designs that efficiently estimate effects assigned larger weight. This dissertation considers a much broader class of potential weighting systems, and hence weighted criteria, by allowing W to be any symmetric, positive definite matrix. Assuming the response and experimental effects may be expressed as a general linear model, we provide a survey of the standard approach to optimal designs based on real-valued, convex functions of information matrices. Motivated by this approach, we introduce fundamental definitions and preliminary results underlying the theory of general weighted optimality. A class of weight matrices is established that allows an experimenter to directly assign weights to a set of estimable functions and we show how optimality of transformed models may be placed under a weighted optimality context. Straightforward modifications to SAS PROC OPTEX are shown to provide an algorithmic search procedure for weighted optimal designs, including A-optimal incomplete block designs. Finally, a general theory is given for design optimization when only a subset of all estimable functions is assumed to be in the model. We use this to develop a weighted criterion to search for A-optimal completely randomized designs for baseline factorial effects assuming all high-order interactions are negligible.
Ph. D.

Pacientes submetidos ao tratamento cirúrgico da obesidade mórbida apresentam perda ponderal acentuada e dismorfismo corporal e, com frequência, solicitam cirurgias plásticas visando um contorno corporal mais adequado. Os resultados dessas cirurgias plásticas são, em parte, limitados pela qualidade da pele resultante do grande emagrecimento. O presente estudo observacional teve como objetivo comparar fragmentos de pele da região epigástrica de 20 pacientes após perda ponderal acentuada consequente à cirurgia bariátrica com 20 pacientes portadores de obesidade mórbida, no sentido de analisar as alterações estruturais da pele como consequência do emagrecimento. A análise histomorfométrica foi realizada sobre o sistema colagênico através da metodologia Picrossírius/luz polarizada, e sobre o sistema elástico através da metodologia resorcinafucsina de Weigert. Foram observados, a redução das fibras colagênicas grossas (p=0,048); o aumento das fibras colagênicas finas (p=0,0085); e o aumento da densidade das fibras elásticas (p=0,0000009033) no grupo de pacientes emagrecidas. Não houve diferença entre os grupos quanto à média de idades (p=0,917) e quantidade total de fibras colágenas (p=0,3619). Os resultados evidenciaram as alterações estruturais da derme decorrentes do emagrecimento acentuado, demonstradas por meio do remodelamento colagênico, com a consequente redução das fibras espessas, organizadas, estruturadas e direcionadas em prol do aumento de fibras finas, desalinhadas e frouxamente dispostas, isso em associação ao aumento da elasticidade da pele. Isto explica cientificamente a já estabelecida percepção clínica das alterações cutâneas dos pacientes emagrecidos após cirurgias bariátricas, apresentando menor resistência e maior flacidez, quando comparadas ao período anterior ao emagrecimento
Post-bariatric patients develop body contour deformities and need plastic surgery procedures for reduction of excess skin and subcutaneous tissue. The results of these contouring procedures are typically limited by the poor quality of the skin. This observational study compared the epigastric skin of 20 post-bariatric with massive weight loss women with 20 women with morbid obesity through histomorphometric analysis of collagen fibers (picrosiriuspolarization) and elastic fibers (Weigert\'s resorcin-fuchsin). A reduction of thick collagen fibers (p=0.048), increase of thin collagen fibers (p=0.0085) and increase of the density of elastic fibers (p=0.0000009) were observed in the group of post-bariatric patients. There was no difference between the groups for mean age (p=0.917) and the total amount of collagen fibers (p=0.3619). These results represent structural changes in the dermis due to the massive weight loss once it demonstrates collagen modifications with reduction of thickness, organized and structured fibers, increase of thin, misaligned and disarranged fibers, and augmentation of the density of elastic fibers. This brings the scientific explanation for the established clinical perception that the skins of post-bariatric patients are less resistant and with more laxity when compared with what they were before the bariatric surgery

Position weight matrices (PWMs) have become a tool of choice for the identification of transcription factor binding sites in DNA sequences. PWMs are compiled from experimentally verified and aligned binding sequences. PWMs are then used to computationally discover novel putative binding sites for a given protein. DNA-binding proteins often show degeneracy in their binding requirement, the overall binding specificity of many proteins is unknown and remains an active area of research. Although PWMs are more reliable predictors than consensus string matching, they generally result in a high number of false positive hits. A previous study introduced a novel method to PWM training based on the known motifs to sample additional putative binding sites from a proximal promoter area. The core idea was further developed, implemented and tested in this thesis with a large scale application. Improved mono- and dinucleotide PWMs were computed for Drosophila melanogaster. The Matthews correlation coefficient was used as an optimization criterion in the PWM refinement algorithm. New PWMs keep an account of non-uniform background nucleotide distributions on the promoters and consider a larger number of new binding sites during the refinement steps. The optimization included the PWM motif length, the position on the promoter, the threshold value and the binding site location. The obtained predictions were compared for mono- and dinucleotide PWM versions with initial matrices and with conventional tools. The optimized PWMs predicted new binding sites with better accuracy than conventional PWMs.

People often make social-related trips to perform activities with their friends. An individual's group of friends can be characterized by his or her social network. While traditional social network data collection is time-consuming and dependent on memory recollection, new online social networking sites may address these shortcomings. This research focuses on the use of tie-strength, the strength of an individual's relationships in his or her social network, to characterize friendships and how this influences an individual's air travel behavior. Four candidate weighting schemes were developed using data collected from a web-based survey which included demographic information, an air travel diary, and friendship information retrieved from Facebook.com. The candidate weight matrices were then tested in a spatial Durbin count model (social model). The results of this study are threefold. First, candidate weighting schemes which consider mutual friendship (i.e. the number of mutual friends two people have in common) exclusively produced higher log-likelihoods than weighting schemes which also consider whether individuals are direct friends (i.e. whether the two individuals are friends themselves). Second, the results of the social model were compared with those of a non-social model. These results suggest that there exist major flaws in using a non-social model to represent variables which may be socially dependent and correlated. Finally, results suggest that individuals tend to have friends who, on average, make more trips than they do. With a growing number of people using online social networks, exploring and understanding friendship influences on travel behavior will help the transportation industry better recognize future travel needs.

Well-bounded operators of type (B) are the building blocks for trigonometrically well-bounded, polar and AC operators. We examine the relationship between polar and AC operators of type (B) and explore the concepts of bounded variation and absolute continuity for functions defined on annuli. In 1973, Hunt, Muckenhoupt and Wheeden showed that the Hilbert transform is a bounded operator on a weighted L^p space precisely when the weight satisfies the A_p condition. This result is proved independently for L^p spaces over the reals, the circle and the integers. We investigate the inter-relationships between these three theorems and show that the theorems for the reals and the integers are equivalent.

Commercial weight loss programmes (CWLPs) are structured weight loss programmes, which are provided to the public by commercial organisations for profit. These programmes offer a weight management service for overweight or obese adults who are willing and able to pay for their participation. There are few studies that have shown CWLPs are more effective than either usual or standard care in various healthcare settings. The extent to which elements of CWLPs contribute to weight reduction is not clear from these studies. The studies presented in this thesis aimed to i) systematically review the effectiveness of CWLPs in randomised controlled trials and ii) to evaluate the effectiveness of a pharmacist-led weight management clinic, Boots Pharmacy Weight Loss Programme (BPWLP), in achieving meaningful weight loss of the initial body weight at three months in overweight and obese clients who received a combination of orlistat, and diet and exercise advice. The systematic review evaluated percentage weight loss or change and used a narrative synthesis. Nine electronic databases (1980-2011) were searched. The review studies published in English were included and their quality was assessed, including assessment of risk of bias. The number of total titles, abstracts and full articles reviewed were 8484, 772 and 153, respectively. The final number of papers included in the review was 20 randomised studies of CWLPs, which were selected based on the application of inclusion and exclusion criteria. The evaluation of the BPWLP involved analysis of data from randomly collected customer record forms (CRFs) for clients who participated in the programme from January 2006 to January 2009. Five hundred and fifty-seven records were collected from 10 Boots pharmacies. Demographics data, history information, biometric data and information about the supply of orlistat were collected. Change in body weight (kg) was compared at baseline and three months using Wilcoxon Signed Rank Test. Seventy percent of the studies included in the systematic review were conducted in the US. There were three potential elements of effective CWLPs, which were calorie restriction, exercise and support. At 12 weeks, mean weight loss ranged from 3.3 to 12.7 kg. The mean weight loss in the BPWLP was 5.8 kg (p < 0.001). Similarly, sensitivity analysis using last-observation-carried-forward (LOCF) showed a statistically significant weight loss (p < 0.001) associated with the BPWLP. Sixty-two percent of clients, who completed the BPWLP, lost at least 5% of their initial body weight at three months. Although the BPWLP had a high dropout rate (70%), clients mainly left the programme because they achieved their desired weight loss. The studies presented in this thesis have shown that CWLPs are effective in helping clients to lose weight. The systematic review shows that the combination of calorie restriction, structured exercise and support is an effective first-line strategy in obesity treatment. The BPWLP, which uses orlistat 120 mg in combination with advice and support on diet and exercise, was shown to be effective in achieving weight loss for clients and is considered a second-line treatment. Health care professionals and policy makers should acknowledge and adopt such strategies in order to tackle the problem of obesity. In particular, pharmacists have an important role to play in facilitating effective weight reduction through the provision of dietary and exercise advice and the prescribing of orlistat. Further study should focus on the factors which contribute to long-term weight maintenance and the cost-effectiveness of CWLPs.

Media promotion of the ideal body as slimness for women and muscularity for men, has led to increasing numbers of both genders reporting dissatisfaction with their bodies and trying to change using weight control products. It has been suggested that pharmacists can play a key role in promoting healthy lifestyles and weight management. The main aim of the research study was to examine the impact of media on body image perception and to investigate the role of pharmacists in weight management. This thesis consists of three studies: an evaluation of weight control websites, a body image survey of young adults and interviews with pharmacists. The results from the evaluation study showed that the quality of most weight loss (64%) and weight gain product advertisements (80%) was generally poor, principally due to the use of misleading claims and a lack of useful information. These data complement the survey that university students reported rarely being influenced by weight control product adverts and hardly considered using these products as a method for changing weight. The survey also showed that most participants of both genders (71%) felt satisfied with their body image. However, the findings in this study indicated that there was a relationship between a high level of body image concern and self-perception of being overweight and the attempt to lose weight. Interviews with pharmacists showed that they were unlikely to be actively involved in reducing obesity problems and promoting healthy lifestyles in the community. Although the prevalence of body dissatisfaction and the use of weight control products among these young adults may not be as high as has been reported elsewhere, healthcare professionals, including pharmacists, need to be aware of this problem when providing advice or consultations for young adults. Healthcare professionals should promote the benefits of healthy lifestyles as well as providing information about potential problems of harmful weight control strategies. The effect of ethnicity and culture on body image concern warrants further. The availability of weight control products and quality of information provided should also be further examined.

Network theory is finding applications in the life and social sciences for ecology, epidemiology, finance and social-ecological systems. While there are methods to generate specific types of networks, the broad literature is focused on generating unweighted networks. In this paper, we present a framework for generating weighted networks that satisfy user- defined criteria. Each criterion hierarchically defines a feature of the network and, in doing so, complements existing algorithms in the literature. We use a general example of ecological species dispersal to illustrate the method and provide open- source code for academic purposes.

The work deals with the safety of technological systems and can be divided into two main thematic units. The attention in the first theoretic unit is paid to aspects that affect the safety of technological systems during their technical life. It describes, together with elementary norms and acts solving the products safety, the most important principles for creating and analysing the safety. It clarifies the origin of company’s risk management, part of its quality management, mentions the faults in which products can be found and also describes the failures which have the biggest effect on these faults and of course on the safety too. Attention is further paid to the reliability analysis, as the tool that helps to create the products safety in the pre-manufacturing phase and also to technical diagnostic, as the tool to keep the safety in after-manufacturing phase. The second practical unit arithmetically analyses the safety of two high-voltage transformers. For that it was used the database of real operation numerical values that were gained during diagnostic investigations on these transformers. In addition it describes mentioned diagnostics methods and gives the new procedure for analyse of transformers’ safety by criteria matrix and weighted sum approach. The main contribution of the work can be considered the checkout and the evaluation of this procedure for use in elaboration of high-voltage transformers diagnostic values for analyzing their safety.

We give a strongly polynomial time combinatorial algorithm to minimise the largest eigenvalue of the weighted Laplacian of a bipartite graph. This is accomplished by solving the dual graph embedding problem which arises from a semidefinite programming formulation. In particular, the problem for trees can be solved in time cubic in the number of vertices.

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The research entitled "Application of multicriteria method in management decision making: a study on the maintenance of logistics equipment" is a study that proposes a matrix for decision making, considering all the criteria of importance, choosing among the alternatives, the most favorable to the current need. Its general objective is to propose a multicriteria analysis model, as an alternative to support in the management decision making, achieved by the following specific objectives: Define the qualitative and quantitative variables of the process; Express the importance of system variables; Propose the best alternative that meets the needs of the system; Demonstrate the tolerance / flexibility margins of the system and Validate the multicriteria analysis model. The theoretical support of the research was based on bibliographical research, documentary analysis and Focus group instrument, starting from the understanding and characterization of the problem, until reaching the modeling of the weighted matrix providing a numerical index of the criterion evaluation, validated through the action research, in a company of the Polo of Two Wheels, with the purpose of assisting in the process of revaluation of the system of maintenance of logistic equipment, whose purpose is to eliminate line stops due to the unavailability of logistic handling equipment. Regarding the results, it was identified that the expectation of the system could be met with 86% satisfaction of the criteria, as opposed to the one reached by the current operator with 44% attendance. In the first stage of the criterial evaluation, the most compromised proposal with the expected results was alternative C, with capacity to meet 66% of expectations. However, this service capacity is below the target of 86%. In the second stage, with the implementation of several actions to develop the supplier, the best alternative was presented by supplier A (the current operator) with 81%. The research demonstrated that the maximum reach is in the evaluation of the alternatives through Multicriteria Analysis, changing the course of the decision, previously taken with intuitive basis, where the decision maker realized that its limiting was the market, and, in developing the market , made it possible to double the capacity of the current operator
A pesquisa intitulada “Aplicação de método multicritério na tomada de decisões gerenciais: um estudo na manutenção de equipamentos logísticos” constitui-se em estudo que propõe uma matriz para tomada de decisão, considerando-se todos os critérios de importância, elegendo dentre as alternativas, a mais favorável à necessidade em curso. Seu objetivo geral é a propositura de um modelo de análise multicritério, como alternativa para suporte na tomada de decisões gerenciais, alcançado pelos seguintes objetivos específicos: Definir as variáveis quali-quantitativas do processo; Expressar a importância das variáveis do sistema; Propor a melhor alternativa que atenda às necessidades do sistema; Demonstrar as margens de tolerância/flexibilidade do sistema e Validar o modelo de análise multicritério. A sustentação teórica da pesquisa baseou-se na pesquisa bibliográfica, na análise documental e no instrumento Focus group, partindo-se do entendimento e caracterização do problema, até atingir a modelagem da matriz ponderada fornecedora de um índice numérico da avaliação criterial, validada através da pesquisa-ação, em empresa do Polo de Duas Rodas, com o objetivo de auxiliar no processo de reavaliação do sistema de manutenção de equipamentos logísticos, cuja finalidade é eliminar as paradas de linha por indisponibilidade de equipamento de movimentação logístico. No que tange aos resultados, identificou-se que a expectativa do sistema poderia ser atendida com 86% de satisfação dos critérios, contrapondo-se ao atingido pelo operador atual com atendimento de 44%. Na primeira etapa da avaliação criterial, a proposta mais comprometida com os resultados esperados era a alternativa C, com capacidade de atendimento de 66% das expectativas. Porém, essa capacidade de atendimento está abaixo da meta que é de 86%. Na segunda Etapa, com a implantação de diversas ações para desenvolver o fornecedor, a melhor alternativa foi apresentada pelo fornecedor A (o atual operador) com 81%. A pesquisa demonstrou como conclusão que o alcance máximo está na avaliação das alternativas através de Análise Multicritério, mudando-se o curso da decisão, antes tomada com base intuitiva, onde o decisor percebeu que seu limitante era o mercado, e, ao desenvolver o mercado, possibilitou dobrar a capacidade do operador atual.

Spectral clustering is often used to partition a data set into a specified number of clusters. Both the unweighted and the vertex-weighted approaches use eigenvectors of the Laplacian matrix of a graph. Our focus is on using vertex-weighted methods to refine clustering of observations. An eigenvector corresponding with the second smallest eigenvalue of the Laplacian matrix of a graph is called a Fiedler vector. Coefficients of a Fiedler vector are used to partition vertices of a given graph into two clusters. A vertex of a graph is classified as unassociated if the Fiedler coefficient of the vertex is close to zero compared to the largest Fiedler coefficient of the graph. We propose a vertex-weighted spectral clustering algorithm which incorporates a vector of weights for each vertex of a given graph to form a vertex-weighted graph. The proposed algorithm predicts association of equidistant or nearly equidistant data points from both clusters while the unweighted clustering does not provide association. Finally, we implemented both the unweighted and the vertex-weighted spectral clustering algorithms on several data sets to show that the proposed algorithm works in general.

The prevalence of obesity worldwide has more than doubled since 1980. The World Health Organisation (WHO) estimates that more than one in ten adults in the global population is obese. Cardiovascular and metabolic health can be improved with moderate weight loss; losses of 5%–10% have been found to improve conditions such as diabetes, hypertension and cholesterol and low-density lipoprotein (LDL) levels. Within the UK, a number of weight management programmes that depend on lifestyle intervention (tier 2) and others that supplement this with drug therapy (tier 3) and surgery (tier 4) are available. The guidelines produced by the Scottish Intercollegiate Guideline Network (SIGN) advocate that weight management programmes address changes to diet, physical activity and behaviour. For patients with a body mass index (BMI) ≥30 kg/m2 or ≥28 kg/m2 in patients with comorbidities, orlistat can be considered as a drug intervention on a case-by-case basis following a full risk and benefit assessment. The objective of the Glasgow and Clyde Weight Management Service (GCWMS), a specialist weight-loss programme, is for patients to lose at least 5 kg. There are a number of metabolic disorders that are associated with obesity. One such disorder is type 2 diabetes mellitus, where weight loss is a standard recommendation to improve blood glucose control. Randomised controlled trials (RCTs) of orlistat indicate that the drug is effective in promoting weight loss and improving metabolic control for those patients with the comorbidity of type 2 diabetes and obesity. There are several different groups of anti-diabetic drugs that can be used to manage diabetes. The effects of the different medications on body weight are considerable. Some, such as biguanides (metformin), dipeptidyl peptidase-4 inhibitors (DPP-IV), Glucagon-like peptide-1 agonist (GLP-1) and sodium-glucose co-transporter-2 inhibitors (SGLT2), either have no effect on weight or can cause weight loss. Others, such as sulfonylureas (SUs) and thiazolidinediones (TZDs) can lead to weight gain. This thesis explores the impact of lifestyle interventions in weight management services, and the impact of drug interventions, on weight loss and glycaemic control. It is supported by the results of five complementary studies that reviewed the effect of orlistat on type 2 diabetes and assessed the impact of the prescription patterns of anti-diabetic drugs in addition to the effects of these pharmacological interventions on weight change in comorbid patients. The first aim of this thesis is to review the evidence of the effects of orlistat on diabetic outcomes. The second aim is to evaluate the lifestyle interventions, and phase 2 of the GCWMS. Finally, the third aim is to determine the prescribing patterns of anti-diabetic drugs, and to observe the association between anti-diabetic medications and weight change. This thesis addresses the following objectives: 1. To undertake a systematic review and meta-analysis of published studies in order to review the evidence of the effects of orlistat on weight loss, specifically concerning glycosylated haemoglobin (HbA1c) and fasting plasma glucose (FPG), using the Cochrane review methodology; 2. To investigate the proportion of patients losing 5 kg of weight, commencing from their entry into the GCWMS programme, until the end of the lifestyle phase of treatment, for individuals of different ages, genders, and socioeconomic groups; 3. To study the proportion of patients losing 5 kg of weight, commencing from their entry into the GCWMS programme, until the end of phase 2, with the three different interventions of orlistat, low-calorie diet (LDL), and further weight loss (FWL); 4. To investigate the proportion of patients referred to the GCWMS on weight-neutral, mixed, and weight-gaining anti-diabetic medications; 5. To investigate the effect of baseline anti-diabetic medications on weight change for patients within a weight management programme. Chapter 2 presents the first study, which was a systemic review that considered the evidence collected in RCTs on the efficacy of orlistat for type 2 diabetes and weight loss. The effects were considered at the biochemical level and included the levels of glycosylated haemoglobin (HbA1c) and fasting plasma glucose (FPG) in people with overweight and obesity. The results, collected from 2,802 participants in 12 trials, were combined into a meta-analysis. The overall finding was that a combination of orlistat and lifestyle intervention yielded superior results. When the results were compared, it was evident that patients who are overweight or obese who were subjected to combined lifestyle and drug intervention lost more weight and had better glycaemic control than patients who were subjected to lifestyle interventions only. Chapter 3 presents the second study which appraised the effectiveness of a real-life NHS lifestyle weight management intervention in reducing body weight by ≥5 kg. The study followed 23,650 patients referred to the GCWMS, of whom 7,329 attended at least two lifestyle intervention sessions. Those individuals had either a BMI of ≥30 kg/m2, with obesity-related comorbidities, or a BMI of ≥35 kg/m2 and were aged ≥18 years. The lifestyle interventions included a combination of a 600 kcal deficit diet, exercise, and behavioural changes. 30% of the overall group succeeded in losing ≥5 kg. Out of those who completed the programme, however, a considerably higher number (46%) lost ≥5 kg. The greatest losers were men, those aged ≥40 years, those with a BMI ≥50 kg/m2, and those from areas that are more affluent. Chapter 4 presents the third study which focused on patients who lost ≥5 kg in phase 2 of the treatment provided by GCWMS which comprised a low-calorie diet (LCD), orlistat 120 mg, three times a day, or further weight loss (FWL). Participants on LCD were prescribed a 1,200 or 1,500 calorie plan; however, those on FWL repeated the lifestyle phase. There were 3,262 participants who attended at least two sessions in phase 2; these were divided into three categories: 536 who took orlistat, 1,043 who followed a LCD and 1,683 who were selected FWL. By the end of phase 2, the levels of success in terms of weight loss across the groups varied from 31% of participants in the orlistat group to 22% of participants in the LCD group and 83% of participants in the FWL group who lost ≥5 kg. Chapter 5 presents the fourth study, which evaluated the pattern of anti-diabetic drug prescriptions for comorbid patients referred to the GCWMS. The study also looked at the proportion of patients who were referred prior to and after the publication of updated SIGN guidelines for the prescription of anti-diabetic medication. In total, the study enrolled 3,063 participants who received anti-diabetic medications, of whom 47.8% received weight-neutral medications, 39.4% had mixed-effect medications and 12.7% took weight-gaining drugs. Prior to the publication of the SIGN guidelines, 11.6% of participants were on weight-gaining drugs, a proportion that did not change significantly one year after the release of the guidelines. Weight-neutral drugs were more commonly prescribed to women, those with a higher BMI and young people. No relationship was observed between the Scottish Index of Multiple Deprivation (SIMD) and anti-diabetic drug prescriptions. Weight-gaining drugs such as SUs and TZDs were more commonly prescribed to older patients and those with lower BMIs. Chapter 6 presents the fifth and final study, which investigated the effect on body weight of anti-diabetic medications in 998 participants following the lifestyle phase of the GCWMS. By the end of the programme, patients who were on weight-neutral anti-diabetic drugs achieved a mean weight change of -3.3 kg (95% confidence interval [CI]: -3.8 to -2.9 kg) and those on weight-gaining drugs achieved a mean weight change of -2.5 kg (95% CI: -3.2 to -1.8 kg), p =0.05.
Among those who completed the programme, the difference was statistically significant (p =0.005). The association between weight change and anti-diabetic drug type was not explained by differences in sex, initial BMI or age. To conclude, there was a clinically and statistically significant change in weight, HbA1c and FPG in patients with obesity and type 2 diabetes who used orlistat. Of the patients following the GCWMS lifestyle phase, less than 50% succeeded in losing at least 5 kg, with patients who completed the programme being more successful. Participants who lost weight in the lifestyle phase were selected for FWL and experienced the greatest weight loss by the end of phase 2. Those who were unsuccessful in losing 5 kg through the lifestyle programme, were offered orlistat and LCD. The large sample size increased the precision of the results, while the stratification for potential confounding factors increased the study’s validity. A higher proportion of patients were prescribed weight-neutral medications, compared with mixed and weight-gaining anti-diabetic medications. The proportion of patients on weight-gaining diabetes drugs referred to the GCWMS did not alter appreciably following the release of the SIGN guidelines. By the end of the lifestyle treatment phase, patients receiving weight-neutral drugs (metformin, DPP-IV, GLP-1, and SGLT2) were more successful in losing weight than those receiving weight-gaining drugs (SUs, TZDs, and any combination including insulin). The main recommendation from this research are, that further studies are carried out to better establish the best timing of use of orlistat within a weight management programme, that the intensity of phase 2 of the GCWMS is increased, and that prescribers take account of a patient’s current BMI prior when prescribing anti-diabetic medication, especially when recommending weight loss and referring to a weight management programme.

A crescente tendência de utilização de materiais austeníticos soldados e cladeados em componentes críticos em alguns setores industriais, como nas indústrias de óleo&gás e nuclear, leva a um aumento na demanda sobre ensaios não-destrutivos confiáveis na avaliação de sua integridade estrutural. Dentre os métodos utilizados na inspeção de soldas cladeados austeníticos estão os métodos de ultrassom por phased array, que são normalmente utilizados na detecção e localização de defeitos. No entanto, componentes com esse tipo de microestrutura são difíceis de inspecionar por phased array devido a anisotropia e inomogeneidade causadas pela microestrutura de grãos grosseiros que costumam levar ao aumento do nível de ruído, ao deslocamento de indicações e ao surgimento de indicações falsas. Sendo assim, a seleção de um método de phased array apropriado precisa levar em conta a habilidade do método em superar os problemas causados pela anisotropia e inomogeneidade. Esta tese apresenta dois métodos de imagem por phased array ultrassônico não-convencionais pensados como formas de ajudar na determinação da integridade de componentes onde soldas e cladeados austeníticos estão presentes. Ambos os métodos tem como base o método de foco total (TFM), sendo que o primeiro é uma extensão do método de leis de atraso adaptativas chamado Método de Foco Total de Atraso Adaptativo (ADTFM) e o segundo método usa fatores de coerência associado à imagens de TFM. A partir dos métodos de imagem aplicados é possível aumentar significativamente a qualidade das imagens por ultrassom em comparação com as imagens padrão obtidas por TFM, especialmente quando foi possível utilizar ambos os métodos combinados.
The increasing trend to use austenitic welded and cladded materials in critical components employed in some industrial sectors, such as the oil&gas and nuclear industries, leads to an increasing demand for their non-destructive assessment by reliable non-destructive methods. Among the methods used to access the integrity of austenitic welds and claddings are the Ultrasonic Phased Array methods, which are usually used to detect the presence and determine the position of defects. However, austenitic welds and claddings are challenging to inspect with Phased Array methods due to the anisotropy and inhomogeneity caused by their coarse grain microstructure, which is capable of increasing noise levels, misplace indications and create false indications. Therefore, the selection of an appropriate phased array method needs to take into account the method’s ability to overcome the impairment caused by anisotropy and inhomogeneity. This thesis presents two non-conventional methods based on ultrasonic phased array imaging techniques designed to assist the structural integrity assessment of components where austenitic welds and clads are present. Both proposed methods are based on the Total Focusing Method (TFM); the first approach is an expansion of the adaptive delay laws concept named Adaptive Delay Total Focusing Method (ADTFM), while the second method uses the coherence weights combined with the TFM images. From the imaging methods applied it was possible to significantly increase the quality of the ultrasonic images in comparison with the standard TFM, primarily when it was possible to combine both approaches.

Computing the weighted geometric mean of large sparse matrices is an operation that tends to become rapidly intractable, when the size of the matrices involved grows. However, if we are not interested in the computation of the matrix function itself, but just in that of its product times a vector, the problem turns simpler and there is a chance to solve it even when the matrix mean would actually be impossible to compute. Our interest is motivated by the fact that this calculation has some practical applications, related to the preconditioning of some operators arising in domain decomposition of elliptic problems. In this thesis, we explore how such a computation can be efficiently performed. First, we exploit the properties of the weighted geometric mean and find several equivalent ways to express it through real powers of a matrix. Hence, we focus our attention on matrix powers and examine how well-known techniques can be adapted to the solution of the problem at hand. In particular, we consider two broad families of approaches for the computation of f(A) v, namely quadrature formulae and Krylov subspace methods, and generalize them to the pencil case f(A\B) v. Finally, we provide an extensive experimental evaluation of the proposed algorithms and also try to assess how convergence speed and execution time are influenced by some characteristics of the input matrices. Our results suggest that a few elements have some bearing on the performance and that, although there is no best choice in general, knowing the conditioning and the sparsity of the arguments beforehand can considerably help in choosing the best strategy to tackle the problem.

As leitoas são consideradas a categoria de matrizes que deve ter uma atenção especial na preparação para a vida produtiva, pois a introdução no momento certo no rebanho de produção é crucial para o desempenho e longevidade desta futura matriz. Todo período experimental deste trabalho foi realizado em uma granja produtora de leitões, localizada no Centro-Oeste do país, com capacidade de alojar 2400 fêmeas (Camborough 22®). O primeiro estudo teve como objetivo determinar se leitoas com maiores taxas de crescimento, em diferentes categorias de idade no início do estímulo à puberdade, apresentam o primeiro estro em idade mais precoce. As leitoas foram avaliadas de acordo com dois grupos de idade à exposição ao cachaço (A= 130-149 d, n= 751 e B= 150-170 d, n= 735) e de acordo com três classes de taxa de crescimento (TC) do nascimento ao início do estímulo (I = 550-649 g/d, n= 371; II= 650-725 g/d, n= 749 e III= 726- 830 g/d, n= 366). A idade no momento da exposição ao cachaço para as leitoas dos Grupos A e B foram 142,6 ± 4,9 e 157,0 ± 5,1 dias, respectivamente. No geral, em 40 dias de estimulação, 85% das leitoas foram púberes. No grupo A, leitoas da classe TCIII manifestaram maior percentual cumulativo de fêmeas em estro dentro de 10 dias (38,1 vs. 29,0 vs. 27,6%) e 20 dias de estimulação (59,7 vs. 48,7 vs. 48,2%) em comparação às classes TCII e TCI, respectivamente (P<0,05). No entanto, dentro do grupo B não houve diferença nos percentuais de fêmeas púberes entre as classes de taxa de crescimento TCIII, TCII e TCI, aos 10 dias (43,2% vs. 45,3% vs. 44,3%) e 20 dias (63,8% vs. 67,3% vs. 63,7%) após a exposição ao macho. Leitoas da classe TCIII estimuladas mais jovens (grupo A) foram mais precoces à puberdade (P<0,05) do que as de baixa taxa de crescimento (159,6 vs 164,8 dias). No entanto, a idade à puberdade não foi afetada pela taxa de crescimento, quando as leitoas foram expostas ao cachaço em idade mais avançada (grupo B). No geral, a idade à puberdade foi positivamente associada com a idade no início da exposição ao cachaço (r=0,38; P<0.0001), e o intervalo de estímulo foi menor (r= -0,19; P<0.0001) em leitoas estimuladas mais velhas. Em conclusão, a estimulação da puberdade pode ser efetuada pela exposição ao macho em idade menos avançada em leitoas com alta taxa de crescimento. O segundo estudo foi desenvolvido com o objetivo de avaliar o reflexo da taxa de crescimento e da espessura de toucinho (ET) na 1ª inseminação, sobre o desempenho subsequente da leitoa e sobre a variação de peso da leitegada ao nascimento. As leitoas foram separadas em três classes de TC do nascimento até a primeira inseminação: TCI (600-700 g/d; n= 345), TCII (701-770 g/d; n= 710) e TCIII (771-870 g/d; n= 366). As análises também foram realizadas considerando três grupos de leitoas de acordo com a ET (mm) na inseminação: ET 10-15 (n= 405), ET 16-17 (n= 649) e ET 18-23 (n= 367). Não houve diferença nas taxas de parto e retorno ao estro entre os grupos de TC e ET (P>0,05). Leitoas TCII e TCIII tiveram, respectivamente, 0,5 e 0,9 leitões a mais quando comparadas às leitoas TCI (P<0,05). Porém, leitoas TCIII apresentaram maior percentual de natimortos intra-parto (P<0,05) em comparação às leitoas das classes TCI e TCII. Leitoas da classe TCIII apresentaram maior número de leitões (P<0,05) pesando abaixo de 1.200 g ao nascimento, comparativamente às leitoas TCI. Além disso, o coeficiente de variação do peso ao nascer foi menor nas fêmeas TCI comparativamente ao das fêmeas TCII e TCIII. Leitoas TCIII apresentaram maior percentual de leitegadas com coeficiente de variação acima de 20%, comparativamente às TCI e TCII (P<0,05). Maiores números de leitões nascidos e nascidos vivos foram observados nas fêmeas do grupo ET16-17 em comparação ao grupo ET10-15 (P<0,05). Não houve diferença entre os grupos de ET no número de natimortos e nem nas variáveis relativas ao peso ao nascer dos leitões (P>0,05). Esses resultados mostram que não há vantagem, em termos de taxa de parto e número de leitões nascidos vivos, em realizar a primeira cobertura de leitoas com ganho de peso acima de 770 g/d e com mais de 17mm de ET. O terceiro estudo teve por objetivo avaliar a influência do peso da primeira inseminação sobre o desempenho reprodutivo e sobre a taxa de descarte ao longo dos três primeiros partos. As leitoas foram classificadas em três grupos, de acordo com seu peso na primeira inseminação: GI (130-150 kg, n= 298), GII (151-170 kg, n= 1007) e GIII (171-200 kg, n= 421). Leitoas do grupo GIII tiverem maior número total de leitões nascidos e maior número de natimortos (P<0,05) no primeiro parto comparativamente aos demais grupos de peso. No entanto, o número total de leitões nascidos em três partos não diferiu entre os grupos (P>0,05). Na inseminação após o primeiro desmame, houve diferença (P<0,05) na taxa de parto entre os três grupos de peso (89,3% vs. 80,3% vs. 74,9%) e a taxa de retorno ao estro foi menor no grupo GI (9,4%) do que nos grupos GII (16,4%) e GIII (19,5%). Ao final dos três partos, houve uma taxa de retenção de 66,6%. As taxas de descarte devido a problemas locomotores e por falha reprodutiva foram, respectivamente 10,8% e 11,2%. A taxa de remoção do grupo GIII (38,9%) foi maior (P= 0,006) do que no grupo GII (31,5%) e tendeu a ser maior (P= 0,06) do que no grupo GI (32,2%). A taxa de descarte devido a problemas locomotores foi superior (P<0,05) em fêmeas com maior peso na primeira inseminação (GIII) comparativamente com as dos grupos GII e GI (15,2% vs. 10,3% vs. 6,0%). Considerando que fêmeas mais pesadas apresentam maior taxa de descarte por problemas locomotores e menor taxa de retenção sem nenhuma falha reprodutiva, ao longo de três ciclos de produção, não é vantajoso realizar o primeiro acasalamento de leitoas com mais de 150 kg de peso corporal.
Gilts are regarded as the class of females that must have special attention in preparation for productive life, because the introduction at the right time in the herd of production is crucial for the future performance and longevity of this female. The studies were performed in a sow farm with capacity to accommodate 2,400 sows (Camborough 22®), located in the Midwest of Brazil (Parallel 14º). The objective of the first study was to verify whether pubertal estrus could be influenced by the growth rate and age of gilts at the onset of boar exposure. Gilts were evaluated according to two groups of age at boar exposure (A= 130-149 d, n= 751 and B= 150- 170 d, n= 735) and three classes of growth rate (Low= 550-649 g/d, n= 371; Intermediate= 650- 725 g/d, n= 749 and High= 726-830 g/d, n= 366). Gilts of groups A and B were, respectively, 142.6 ± 4.9 and 157.0 ± 5.1 days of age at the onset of boar exposure. Overall, 85% of gilts showed estrus within 40 days of boar exposure. Within group A gilts a higher (P<0.05) cumulative percentage of estrus within 10 days (38.1 vs. 29.0 vs. 27.6%) and 20 days (59.7% vs. 48.7% vs. 48.2%) of stimulation was observed in High than in Intermediate and Low growth rate gilts. Nevertheless, within group B there was no difference (P<0.05) in the percentage of estrus among High, Intermediate and Low growth rate classes within 10 days (43.2% vs. 45.3% vs. 44.3%) and 20 days (63.8% vs. 67.3% vs. 63.7%) of boar stimulation. Within group A, puberty was attained earlier (P<0.05) in High than in Low growth rate gilts (159.6 vs. 164.8 days). However, age at puberty was not affected by growth rate, when gilts were exposed to boar at an older age (group B). Overall, age at puberty was positively associated with the age at the onset of boar exposure (r= 0.38; P<0.0001) and the older the gilts were at boar exposure the lower was the interval (r= -0.19; P<0.0001) from stimulation to onset of puberty. In conclusion, successful stimulation of puberty can be obtained through an earlier exposure to boars in high growth rate gilts. The second study evaluated the influence of growth rate (GR) and backfat thickness (BF), at first mating of gilts, on the reproductive performance until the first farrowing and on the variation in birth weight of piglets. Gilts were categorized into three groups according to GR from birth until first mating: GRI (600-700 g/d, n= 345), GRII (701-770 g/d, n= 710) and GRIII (771-870 g/d, n= 366). Analyses were also performed considering three groups formed according to BF (mm) at mating: BF10-15 (n= 405); BF16-17 (n= 649) and BF18-23 (n= 367). There were no differences in farrowing rate and return to estrus rate among BF or GR groups (P>0.05). GRII and GRIII females had larger litter size compared to GRI gilts (P<0.05), respectively 0.5 and 0.9 more piglets, but a higher percentage of intrapartum stillborns (P<0.05) was observed in GRIII than in GRI and GRII females. Moreover GRIII females had more piglets (P<0.05) weighing less than 1,200 g, litters with a higher coefficient of variation for birth weight and a higher percentage of litters with coefficient of variation above 20% (P<0.05) than GRI females. More total born and born alive piglets were observed in BF16-17 compared with BF10-15 females (P<0.05).There were no differences among BF groups in number of stillborn neither in variables concerning the birth weight of piglets (P>0.05). These results show that there is no advantage, in terms of farrowing rate and number of born alive, in performing the first mating of gilts with GR >770g/d and BF >17 mm. The objective of the third study was to evaluate the influence of the weight at the first mating of gilts on the reproductive performance and on the removal rate until the third farrowing. Gilts were categorized into three groups according to weight at first mating: GI (130- 150 kg, n= 298), GII (151-170 kg, n= 1007) and GIII (171-200 kg, n= 421). In the first farrowing, GIII females had larger litter size compared to GRI and GII gilts (P<0.05), but a higher percentage of stillborns (P<0.05) also was observed in GRIII than in GRI and GRII females. However, total born over three parities were not different among groups (P>0.05). In the insemination after the first weaning, there were differences (P<0.05) in farrowing rate among all weight groups (89.3% vs. 80.3% vs. 74.9%) and return to estrus rate was lower in GI (9.4%) than in GII (16.4%) and GIII (19.5%) groups. The overall retention rate over three parities was 66.6%. Culling rate due to locomotion problems was 10.8% and due to reproductive failure was 11.2%.The removal rate over three parities in GIII females (38.9%) was higher (P= 0.006) than in GII females (31.5%) and tended to be higher (P= 0.06) than in GI females (32.2%). The culling rate due to locomotors problems was different (P<0.05) among all groups (6.0% vs. 10.3% vs. 15.2% for GI, GII and GIII, respectively). Taking into account that heavy females have higher culling rates due to locomotors disorders and lower retention rate without reproductive failure, over three productive cycles, it is not advantageous to perform the first mating of gilts with more than 150 kg of body weight.

Information retrieval is much more challenging than traditional small document collection retrieval. The main difference is the importance of correlations between related concepts in complex data structures. These structures have been studied by several information retrieval systems. This research began by performing a comprehensive review and comparison of several techniques of matrix dimensionality estimation and their respective effects on enhancing retrieval performance using singular value decomposition and latent semantic analysis. Two novel techniques have been introduced in this research to enhance intrinsic dimensionality estimation, the Multi-criteria Decision Weighted model to estimate matrix intrinsic dimensionality for large document collections and the Average Standard Estimator (ASE) for estimating data intrinsic dimensionality based on the singular value decomposition (SVD). ASE estimates the level of significance for singular values resulting from the singular value decomposition. ASE assumes that those variables with deep relations have sufficient correlation and that only those relationships with high singular values are significant and should be maintained. Experimental results over all possible dimensions indicated that ASE improved matrix intrinsic dimensionality estimation by including the effect of both singular values magnitude of decrease and random noise distracters. Analysis based on selected performance measures indicates that for each document collection there is a region of lower dimensionalities associated with improved retrieval performance. However, there was clear disagreement between the various performance measures on the model associated with best performance. The introduction of the multi-weighted model and Analytical Hierarchy Processing (AHP) analysis helped in ranking dimensionality estimation techniques and facilitates satisfying overall model goals by leveraging contradicting constrains and satisfying information retrieval priorities. ASE provided the best estimate for MEDLINE intrinsic dimensionality among all other dimensionality estimation techniques, and further, ASE improved precision and relative relevance by 10.2% and 7.4% respectively. AHP analysis indicates that ASE and the weighted model ranked the best among other methods with 30.3% and 20.3% in satisfying overall model goals in MEDLINE and 22.6% and 25.1% for CRANFIELD. The weighted model improved MEDLINE relative relevance by 4.4%, while the scree plot, weighted model, and ASE provided better estimation of data intrinsic dimensionality for CRANFIELD collection than Kaiser-Guttman and Percentage of variance. ASE dimensionality estimation technique provided a better estimation of CISI intrinsic dimensionality than all other tested methods since all methods except ASE tend to underestimate CISI document collection intrinsic dimensionality. ASE improved CISI average relative relevance and average search length by 28.4% and 22.0% respectively. This research provided evidence supporting a system using a weighted multi-criteria performance evaluation technique resulting in better overall performance than a single criteria ranking model. Thus, the weighted multi-criteria model with dimensionality reduction provides a more efficient implementation for information retrieval than using a full rank model.
Ph.D.
Department of Industrial Engineering and Management Systems
Engineering and Computer Science
Industrial Engineering PhD

Foram realizados 4 experimentos com o objetivo de avaliar distribuições de nascimentos em função da idade da matriz, e as conseqüências de períodos prolongados de permanência das aves no nascedouro sobre seu futuro desempenho, procurando estabelecer novos manejos que busquem melhorias na qualidade do pintinho. Observou-se que a idade da matriz interferiu nas distribuições de nascimentos, sendo que embriões oriundos de matrizes velhas apresentam distribuição de nascimentos mais tardias, em relação a embriões oriundos de matrizes jovem e de idade intermediária. Constatou-se que a grande maioria das eclosões ocorreram até 485 horas de incubação, ou seja, 30 horas antes do prazo final de retirada. Partindo deste pressuposto, se poderia remover os pintos, pelo menos uma vez, antes de 510 horas de incubação, que é o período normalmente utilizado. Dessa forma, o período em que as aves ficariam sem alimento e água seria reduzido para a maioria dos pintos eclodidos. No entanto, os resultados deste estudo não mostram vantagem na adoção deste manejo, visto que pintos retirados precocemente do nascedouro não apresentaram vantagens de desempenho em relação a pintos submetidos a períodos de estresse de 12 e 24 horas dentro do nascedouro, para posterior alojamento. Matrizes velhas apresentam maior número de ovos inférteis e mortalidade embrionária total, resultando em menor percentual de eclodibilidade. A antecipação ou o retardamento da troca de dieta inicial por crescimento em função do peso do pinto ao alojamento, não se mostrou benéfica em termos de desempenho dos animais. No entanto, pode-se constatar que o peso ao alojamento foi determinante para o desempenho dos animais, resultando em diferença média de 174g, aos 42 dias, favoráveis às aves alojadas com um maior peso corporal.
Four experiences were made with the purpose of evaluating birth distribution related to the broiler breeder age and the consequences of the chick permanence in the hatchery for a long period on their future performance. Attempting to establish new handling to improve chick quality we observed that the broiler breeder age interfered in hatching distribution and the embryo from old broiler breeders present a later distribution in relation to the embryo from young broiler breeders and intermediate broiler breeders. We observed that most hatching occurred till 485 hours of incubation, that is, 30 hours before the final removing term. From this postulation, it would be interesting that the chick would be removed, at least once, before 510 hours of incubation, which is the used normal period. In this way, the period in which the chick will be without food and water will be reduced to the majority of the hatching chicks. Nevertheless, the results of this study do not show advantages in the adoption of this handling, since the chicks taken away early from the birthplace do not present performance advantages related to the chicks submitted to stress periods of 12 an 24 hours in the hatchery for posterior housing. Old broiler breeder present a great number of infertile eggs and total embryonic mortality resulting in a minor percentage of hatching. The anticipation or the retarding of the exchange of the initial diet in view of the growth due to the chick weight in housing was not advantageous in relation to the animal performance. Nevertheless, we evidence that the weight in housing was determinant for the animal performance resulting in a medium difference of weight of 174g at the day 42th, favorable to the chicks housed with a greater corporal weight.

Hedonic pricing methods and GIS (Geographic Information Systems) were used to evaluate relationships between sale price of single family homes and landscape fragmentation and natural land cover. Spatial regression analyses found that sale prices increase as landscapes become less fragmented and the amount of natural land cover around a home increases. The projected growth in population and employment in the Richmond, Virginia region and subsequent increases in land development and landscape fragmentation presents a challenge to sustaining intact healthy ecosystems in the Richmond region. Spatial regression analyses helped illuminate how land cover patterns influence sale prices and landscape patterns that are economically and ecologically advantageous.

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Aiming to evaluate the effects of broiler breeder´s age and egg weight on the performance, two experiments were conducted using increasing levels of sulfur amino acids. For each experiment, 320 chicks from a commercial hatchery were used. The experimental design was randomized blocks due to the sex of chicks in a 2x4 factorial arrangement. The chicks´ performance was evaluated according to the breeders age and the egg weight combined with high levels of methionine and digestible cystine in the pre-starter ration (0.810, 0.910, 1.010 and 1.110%), in a total of eight experimental groups and four replicates of 10 birds each, The eggs were separated, weighed and distributed in a stroller in a commercial incubator, with constant temperature at 37.8 ºC and humidity between 60 and 65%. Chicks from old and new breeders and two different egg weights were submitted to necropsy, biometry of the intestinal tract (GIT) organs, and intestinal histomorphometry were performed. Blood was collected for glucose analysis at 19 days of embryo, and after hatching, at seven and 14 days of life. The rest of the chicks were submitted to a metabolism trial at four and seven days of age, by the method of excreta collection and the nitrogen balance was determined (g). Other autopsies were carried out at seven and 14 days of life with the performance of the same analyses previously described. The broilers performance was not evaluated up to 21 days of life. Data were submitted to analysis of variance and polynomial regression for the levels of sulfur amino acids according to SAS (2004). A higher initial development was observed in young breeders for both biometry of digestive organs and intestine histomorphometry .This development is more evident in chicks of older breeders. The differences found in the experiment with different egg weights show a better development of embryos and chicks for eggs weighing 70 g. Chicks from 70-g-eggs and 45-week-old breeders were heavier. Average levels of 0.910% and 1.010% of methionine + digestible cystine in the pre-starter ration resulted in performance and nutrient retention more suitable for broiler chicks in both experiments. Based on feed conversion, we suggest the minimum recommendation of 0.810%.
Com o objetivo de avaliar os efeitos da idade da matriz de frango de corte e do peso dos ovos foram conduzidos dois experimentos em que se discute sua relação com o desempenho utilizando níveis crescentes de aminoácidos sulfurados. Para cada experimento utilizaram-se 320 pintos provenientes de um incubatório comercial. O delineamento experimental foi em blocos casualizados devido ao sexo dos pintos, em esquema fatorial 2x4. Foi avaliado o desempenho dos pintos com idades de matrizes e peso dos ovos combinado com níveis de metionina+cistina digestível na ração pré-inicial (0,810; 0,910; 1,010 e 1,110%), totalizando oito grupos experimentais e quatro repetições de 10 aves cada, considerando os sexos macho e fêmea. Os ovos foram separados, pesados e distribuídos em um carrinho na incubadora comercial e a temperatura foi mantida constante a 37,8ºC e umidade entre 60 e 65%. Foram necropsiados pintos oriundos de matriz nova e velha e dois pesos de ovos, feita a biometria dos órgãos do trato intestinal (TGI), histomorfometria intestinal, coletados sangue para análise de glicose aos 19 dias de embrião, após a eclosão, sete e 14 dias de vida. O restante dos pintos alojados foi realizado um ensaio metabólico aos quatro a sete dias de idade, pelo método da colheita total de excretas e determinado o balanço de nitrogênio (g) e outras necropsias aos sete e 14 dias de vida e realizado as mesmas análises anteriores. No foram avaliados o desempenho dos frangos até 21 dias de idade. Os dados foram submetidos à análise de variância e realizado regressão polinomial para níveis de aminoácidos sulfurados de acordo com o programa computacional SAS (2004). Observou um maior desenvolvimento inicial em matrizes jovens tanto para biometria dos órgãos digestores quanto para histomorfometria intestinal sendo que esse desenvolvimento é mais evidente pintos de matrizes mais velhas. Já as diferenças encontradas no experimento de diferentes pesos de ovos foram um melhor desenvolvimento de embriões e pintos para pesos de ovos com 70 gramas. Pintos oriundos de ovos com 70 gramas e de matrizes com 45 semanas foram mais pesados. Níveis médios de 0,910% e 1,010% metionina+cistina digestível na fase pré-inicial propiciaram resultados de desempenho e retenção de nutrientes mais adequados em pintos de corte em ambos experimentos. Com base na conversão alimentar, sugerese a recomendação mínima de 0,810%