Estudo da ligação entre componentes estruturais de GFRP (glass fiber reinforced polymer) e componentes estruturais em betão

Dissertação de mestrado integrado em Engenharia Civil

Nutritional composition, quality and spoilage capacity of orange roughy (Hoplostethus atlanticus) from the North East Atlantic

The nutritional composition o f orange roughy (collected from the Northeast Atlantic near the Rockall Trough) was studied on a seasonal basis. In addition samples were aged and stability assessed. Protein levels (16.68-16.21% w/w) were found to be slightly higher than those recorded for the N ew Zealand species o f orange roughy and compared favourably with protein values for fish muscle in general. Statistically results show a significant seasonal variation with no variation from fish to fish or in the location within the fish. Lipid content (3.6-4.5% w/w) was found to be much lower than that recorded for New Zealand. As with protein statistically results show a significant seasonal variation and no variation from fish to fish or in the location within the fish. Moisture levels (77.3_79.6%w/w) compared favourably with values obtained from other studies. Again statistically results show a significant seasonal variation with no variation from fish to fish or within the fish. Iodine values (74.63-79.54) indicate the likely presence o f a high level o f mono unsaturated fatty acids. Statistically results show no significant seasonal variation and no sample variation or variation within fish. Thin layer chromatography o f the extracted fat showed the major type to be wax esters with a much lower amount o f triglycerides and smaller amounts of polar lipids, free sterols and free fatty acids. Total fatty acid composition was found to be very similar to that recorded from other studies and showed that most o f the oils extracted from the fish muscle contained a high percentage o f mono unsaturates namely 16:1,18:1, 20:1 and 22:1 (85.63 - 91.14% ) with 16:1 present in the smallest amounts and 18:1 the major one. The only saturated fatty M.Sc. in Biochemistry III Nutritional Composition, Quality and Spoilage Capacity of Specific Deep Sea Fish acids present in significant quantities were 14:0, 16:0 and 18:0, the total varied from a seasonal average high o f 4.05 % to an average low o f 2.27%. The polyunsaturated fatty acids linoleic and arachidonic acid were present in small quantities varying in total from 0.89% to 1.50%. Docosapentaenoic acid (D P A ) was found only in trace quantities in spring, autumn and winter samples and undetected in summer. Levels o f Eicosapentaenoic acid (EPA ) and Docosahexaenoic acid (D H A ) were also found in very low percentages and varied on a seasonal basis with average values ranging from 0.41% in summer to 1.03 % in autumn for EPA and from 1.44 % in summer to3.20 % in autumn for D H A . Again statistically results show a significant seasonal variation with no variation from fish to fish or location within the fish. Levels o f freshness were measured using the Thiobarbituric acid (T B A ), Total volatile base nitrogen (T V B -N ) and Trimethylamine (T M A ) techniques. The quality o f the fish upon arrival was excellent and well below legal/acceptable lim its.T V B -N values ranged from 6.88-8.91 mg/lOOg and T M A values from 4.82-6.46 mg/lOOg Values for T B A ranged from 0.18-0.35 mg Malonaldehyde/kg fish. The summer values were higher than the other seasons. Seasonal variation was significant for all methods with no variation from fish to fish or within the fish. Fish aged at +4°C in air did not exceed the T V B N lim it o f 35mg/100g until day 6 whereas the T V B N lim it was extended to 8 days for fish aged at +4°C in vacuum. However the T M A lim it o f 12mg/100g was reached on day 4 for fish stored at +4°C in air and on day 5 for vacuum packed samples stored at +4°C . Fish stored at -5°C in air and vacuum packed did not reach the T V B N lim it until day 61 but the T M A limit was reached on day 24 for fish stored at -5°C in air and was extended to 31 days for vacuum packed fish stored at-5°C. Prolonged storage at -18°C caused some deterioration o f the frozen fish muscle. Upon thawing the shelf life o f fish stored for 12 months was much shorter than that stored for 6 M.Sc. in Biochemistry IV Nutritional Composition, Quality and Spoilage Capacity of Specific Deep Sea Fish months. This in turn deteriorated faster than fresh fish held at refridgeration temperature in air. Orange roughy were found to be a good source of protein with moisture levels similar to that o f other fish. They were o f medium fat content but have a very poor content o f the essential omega 3 and omega 6 fatty acids. Orange roughy can be stored at -18°C but its subsequent refridgerated shelf life will be shorter than that o f unfrozen orange roughy stored at refridgeration temperature. Orange roughy are a very important part o f the ecosystem. Their composition is less nutritionally beneficial than more readily available fish for human consumption and therefore should not be fished at all

Verbreitung des Bibers (Castor fiber LINNAEUS 1758) im Biosphärenreservat Oberlausitzer Heide- und Teichlandschaft

Die Arbeit zeichnet die Verbreitung des Bibers (Castor fiber LINNEAUS 1758) im Biosphärenreservat Oberlausitzer Heide- und Teichlandschaft für das Jahr 2014 nach. Auf Grundlage der zwei wöchigen Feldarbeit im Februar 2014 wurden Aktivitätsspuren gesichtet und mit einem GPS Gerät registriert und fotografisch dokumentiert. Daraus werden Verbreitungskarten mit genauer Lage und Umfang der einzelnen Reviere dargestellt. Insgesamt wurden sieben Reviere entdeckt. Davon befinden sich vier Reviere an der Spree und ein Revier am Schwarzen Schöps. Die restlichen zwei Reviere wurden in Teichgruppen, die sich in der unmittelbaren Nähe der Spree befinden, verzeichnet. Des Weiteren erfolgte der Kontakt zu unterschiedlichen Akteuren die sich mit der Verbreitung des Bibers in Ost-Sachsen befassen. Zu den ermittelten Ergebnissen wurden die anderen Standorte eingebunden und kartografisch in einer Verbreitungskarte dargestellt.

Sparse regularization for fiber ODF reconstruction: from the suboptimality of ℓ2 and ℓ1 priors to ℓ0.

Diffusion MRI is a well established imaging modality providing a powerful way to probe the structure of the white matter non-invasively. Despite its potential, the intrinsic long scan times of these sequences have hampered their use in clinical practice. For this reason, a large variety of methods have been recently proposed to shorten the acquisition times. Among them, spherical deconvolution approaches have gained a lot of interest for their ability to reliably recover the intra-voxel fiber configuration with a relatively small number of data samples. To overcome the intrinsic instabilities of deconvolution, these methods use regularization schemes generally based on the assumption that the fiber orientation distribution (FOD) to be recovered in each voxel is sparse. The well known Constrained Spherical Deconvolution (CSD) approach resorts to Tikhonov regularization, based on an ℓ(2)-norm prior, which promotes a weak version of sparsity. Also, in the last few years compressed sensing has been advocated to further accelerate the acquisitions and ℓ(1)-norm minimization is generally employed as a means to promote sparsity in the recovered FODs. In this paper, we provide evidence that the use of an ℓ(1)-norm prior to regularize this class of problems is somewhat inconsistent with the fact that the fiber compartments all sum up to unity. To overcome this ℓ(1) inconsistency while simultaneously exploiting sparsity more optimally than through an ℓ(2) prior, we reformulate the reconstruction problem as a constrained formulation between a data term and a sparsity prior consisting in an explicit bound on the ℓ(0)norm of the FOD, i.e. on the number of fibers. The method has been tested both on synthetic and real data. Experimental results show that the proposed ℓ(0) formulation significantly reduces modeling errors compared to the state-of-the-art ℓ(2) and ℓ(1) regularization approaches.

Quantitative comparison of reconstruction methods for intra-voxel fiber recovery from diffusion MRI.

Validation is arguably the bottleneck in the diffusion magnetic resonance imaging (MRI) community. This paper evaluates and compares 20 algorithms for recovering the local intra-voxel fiber structure from diffusion MRI data and is based on the results of the "HARDI reconstruction challenge" organized in the context of the "ISBI 2012" conference. Evaluated methods encompass a mixture of classical techniques well known in the literature such as diffusion tensor, Q-Ball and diffusion spectrum imaging, algorithms inspired by the recent theory of compressed sensing and also brand new approaches proposed for the first time at this contest. To quantitatively compare the methods under controlled conditions, two datasets with known ground-truth were synthetically generated and two main criteria were used to evaluate the quality of the reconstructions in every voxel: correct assessment of the number of fiber populations and angular accuracy in their orientation. This comparative study investigates the behavior of every algorithm with varying experimental conditions and highlights strengths and weaknesses of each approach. This information can be useful not only for enhancing current algorithms and develop the next generation of reconstruction methods, but also to assist physicians in the choice of the most adequate technique for their studies.

PGC1alpha expression is controlled in skeletal muscles by PPARbeta, whose ablation results in fiber-type switching, obesity, and type 2 diabetes.

Mice in which peroxisome proliferator-activated receptor beta (PPARbeta) is selectively ablated in skeletal muscle myocytes were generated to elucidate the role played by PPARbeta signaling in these myocytes. These somatic mutant mice exhibited a muscle fiber-type switching toward lower oxidative capacity that preceded the development of obesity and diabetes, thus demonstrating that PPARbeta is instrumental in myocytes to the maintenance of oxidative fibers and that fiber-type switching is likely to be the cause and not the consequence of these metabolic disorders. We also show that PPARbeta stimulates in myocytes the expression of PGC1alpha, a coactivator of various transcription factors, known to play an important role in slow muscle fiber formation. Moreover, as the PGC1alpha promoter contains a PPAR response element, the effect of PPARbeta on the formation and/or maintenance of slow muscle fibers can be ascribed, at least in part, to a stimulation of PGC1alpha expression at the transcriptional level.

Diagnosis of malaria by acridine orange fluorescent microscopy in an endemic area of Venezuela

Fluorescent (acridine orange) microscopical examination of capillary centrifuged blood (quantitative buffy coat [QBC®] analysis) and Giemsa stained thick blood smears (GTS) were compared for diagnosis of malaria in blood specimens from adults living in malaria transmission areas of the States of Bolivar and Amazonas in southeastern and south Venezuela, respectively. Of a total of 198 GTS examined, 95 subjects (48%) showed parasitaemia. Among the 95 blood films with a positive GTS, 94 were judged positive by the QBC. However, positive QBC tubes were found in 29 out of 103 blood specimens with a negative GTS. Thus, relative to a GTS standard, the sensitivity and specificity of the QBC-test was 99.2% and 72%, respectively. Young trophozoites of Plasmodium vivax and P. falciparum could not be distinguished with certainty. It is confirmed that the QBC offers many advantages compared with the standard diagnosis of malaria parasites, specifically in the speed of staining and ease of interpretation. However, in places where P. falciparum and P. vivax occur, species and stage differentiation should be confirmed with the GTS.

Recent development in optical fiber biosensors

Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

A Monte Carlo-Based Fiber Tracking Algorithm using Diffusion Tensor MRI

Diffusion tensor magnetic resonance imaging, which measures directional information of water diffusion in the brain, has emerged as a powerful tool for human brain studies. In this paper, we introduce a new Monte Carlo-based fiber tracking approach to estimate brain connectivity. One of the main characteristics of this approach is that all parameters of the algorithm are automatically determined at each point using the entropy of the eigenvalues of the diffusion tensor. Experimental results show the good performance of the proposed approach

Response to comment on "the geometric structure of the brain fiber pathways".

In response to Catani et al., we show that corticospinal pathways adhere via sharp turns to two local grid orientations; that our studies have three times the diffusion resolution of those compared; and that the noted technical concerns, including crossing angles, do not challenge the evidence of mathematically specific geometric structure. Thus, the geometric thesis gives the best account of the available evidence.

Power and selection of contract terms: The case from the Brazilian orange juice sector

ABSTRACT We propose a model to explain how contract terms are selected in the presence of a form of economic power: contract power. The orange juice sector is used to illustrate an analysis that demonstrates the effects of contract power on the economic organization of the sector. We define contract power as the ability to exploit contractual gaps or failures of contractual provisions, which are strategically left incomplete. Empirical evidence from content analysis of antitrust documents supports the logic of contract power in the orange juice sector in three forms: avoiding changes to payment methods from weight to solid contents (quality); using information asymmetries to manipulate indexes that calculate the formula of orange prices; and deliberately harvesting oranges late in order to dehydrate the fruit, which consequently reduces weight and price. The paper contributes to understanding the selection of contract terms and the debate about how antitrust offices can deal with this issue.

Universality class of fiber bundles with strong heterogeneities

We study the effect of strong heterogeneities on the fracture of disordered materials using a fiber bundle model. The bundle is composed of two subsets of fibers, i.e. a fraction 0 ≤ α ≤ 1 of fibers is unbreakable, while the remaining 1 - α fraction is characterized by a distribution of breaking thresholds. Assuming global load sharing, we show analytically that there exists a critical fraction of the components αc which separates two qualitatively diferent regimes of the system: below αc the burst size distribution is a power law with the usual exponent Ƭ= 5/2, while above αc the exponent switches to a lower value Ƭ = 9/4 and a cutoff function occurs with a diverging characteristic size. Analyzing the macroscopic response of the system we demonstrate that the transition is conditioned to disorder distributions where the constitutive curve has a single maximum and an inflexion point defining a novel universality class of breakdown phenomena

Avalanche dynamics of fiber bundle models

We present a detailed analytical and numerical study of the avalanche distributions of the continuous damage fiber bundle model CDFBM . Linearly elastic fibers undergo a series of partial failure events which give rise to a gradual degradation of their stiffness. We show that the model reproduces a wide range of mechanical behaviors. We find that macroscopic hardening and plastic responses are characterized by avalanche distributions, which exhibit an algebraic decay with exponents between 5/2 and 2 different from those observed in mean-field fiber bundle models. We also derive analytically the phase diagram of a family of CDFBM which covers a large variety of potential avalanche size distributions. Our results provide a unified view of the statistics of breaking avalanches in fiber bundle models