Dynamical analysis in growth models: Blumberg’s equation

We present a new dynamical approach to the Blumberg's equation, a family of unimodal maps. These maps are proportional to Beta(p, q) probability densities functions. Using the symmetry of the Beta(p, q) distribution and symbolic dynamics techniques, a new concept of mirror symmetry is defined for this family of maps. The kneading theory is used to analyze the effect of such symmetry in the presented models. The main result proves that two mirror symmetric unimodal maps have the same topological entropy. Different population dynamics regimes are identified, when the intrinsic growth rate is modified: extinctions, stabilities, bifurcations, chaos and Allee effect. To illustrate our results, we present a numerical analysis, where are demonstrated: monotonicity of the topological entropy with the variation of the intrinsic growth rate, existence of isentropic sets in the parameters space and mirror symmetry.

Optoelectronic Logic Functions Based on Reconfigurable SiC Multilayer Devices

WDM multilayered SiC/Si devices based on a-Si:H and a-SiC:H filter design are approached from a reconfigurable point of view. Results show that the devices, under appropriated optical bias, act as reconfigurable active filters that allow optical switching and optoelectronic logic functions development. Under front violet irradiation the magnitude of the red and green channels are amplified and the blue and violet reduced. Violet back irradiation cuts the red channel, slightly influences the magnitude of the green and blue ones and strongly amplifies de violet channel. This nonlinearity provides the possibility for selective removal of useless wavelengths. Particular attention is given to the amplification coefficient weights, which allow taking into account the wavelength background effects when a band needs to be filtered from a wider range of mixed signals, or when optical active filter gates are used to select and filter input signals to specific output ports in WDM communication systems. A truth table of an encoder that performs 8-to-1 multiplexer (MUX) function is presented.

Non-coding RNAs: multi-tasking molecules in the cell

In the last years it has become increasingly clear that the mammalian transcriptome is highly complex and includes a large number of small non-coding RNAs (sncRNAs) and long noncoding RNAs (lncRNAs). Here we review the biogenesis pathways of the three classes of sncRNAs, namely short interfering RNAs (siRNAs), microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs). These ncRNAs have been extensively studied and are involved in pathways leading to specific gene silencing and the protection of genomes against virus and transposons, for example. Also, lncRNAs have emerged as pivotal molecules for the transcriptional and post-transcriptional regulation of gene expression which is supported by their tissue-specific expression patterns, subcellular distribution, and developmental regulation. Therefore, we also focus our attention on their role in differentiation and development. SncRNAs and lncRNAs play critical roles in defining DNA methylation patterns, as well as chromatin remodeling thus having a substantial effect in epigenetics. The identification of some overlaps in their biogenesis pathways and functional roles raises the hypothesis that these molecules play concerted functions in vivo, creating complex regulatory networks where cooperation with regulatory proteins is necessary. We also highlighted the implications of biogenesis and gene expression deregulation of sncRNAs and lncRNAs in human diseases like cancer.

Lubrificação de compressores que aspiram fluido frigorigéneo a temperaturas inferiores a -30° C

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

The three-loop SSM beta-functions

We present the supersymmetric standard model three-loop beta-functions for gauge and Yukawa couplings and consider the effect of three-loop corrections on the standard running coupling analyses.

Water quality in lakes and reservoirs in China

Dissertation elaborated for the partial fulfilment of the requirements of the Master Degree in Civil Engineering in the Speciality Area of Hydarulics

Particulate matter distribution in selected Portuguese archives: a preliminary study

Particulate matter (PM) can have a significant impact on human health and on artifacts stored and kept inside museums and archives. To the author's knowledge, its immediate and/or longterm concentrations and distribution on Portuguese archives has never been determined. Four Portuguese archives (with and without HVAC/air filtration systems) were selected and the immediate concentration of airborne particulate matter was measured by active sampling. Indoor-outdoor ratios were also determined. International and national guidelines were used to ascertain the environment’s quality, both for the readers and staff and for the documents preserved in these institutions. Inside, PM2.5 ranged between 0.37μg/m3 and 27.61μg/m3, while PM10 ranged between 4.43μg/m3 and 285.52μg/m3. The lowest values were determined in storage rooms and the highest in reading rooms. In terms of human health, Portuguese guidelines for immediate PM10 concentration were not met in several locations. For conservation purposes, storage rooms were classified according to an original air quality grid. Air filtration systems proved valuable in maintaining a safe environment for our written heritage and the staff and readers that deal with it and care for it every day. This study constitutes the first snapshot of the particulate matter concentrations and distribution in Portuguese Archives.

Logic functions based on optical bias controlled SIC Tandem devices

The purpose of this paper is the design of an optoelectronic circuit based on a-SiC technology, able to act simultaneously as a 4-bit binary encoder or a binary decoder in a 4-to-16 line configurations and show multiplexer-based logical functions. The device consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n multilayered structure produced by PECVD. To analyze it under information-modulated wave (color channels) and uniform irradiation (background) four monochromatic pulsed lights (input channels): red, green, blue and violet shine on the device. Steady state optical bias was superimposed separately from the front and the back sides, and the generated photocurrent was measured. Results show that the devices, under appropriate optical bias, act as reconfigurable active filters that allow optical switching and optoelectronic logic functions development providing the possibility for selective removal of useless wavelengths. The logic functions needed to construct any other complex logic functions are the NOT, and both or either an AND or an OR. Any other complex logic function that might be found can also be used as building blocks to achieve the functions needed for the retrieval of channels within the WDM communication link. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

New water-soluble Ruthenium(II) cytotoxic complex: biological activity and celular distribution

A novel water soluble organometallic compound, [RuCp(mTPPMSNa)(2,2'-bipy)][CF3SO3] (TM85, where Cp=eta(5)-cyclopentadienyl, mTPPMS = diphenylphosphane-benzene-3-sulfonate and 2,2'-bipy = 2,2'-bipyridine) is presented herein. Studies of interactions with relevant proteins were performed to understand the behavior and mode of action of this complex in the biological environment. Electrochemical and fluorescence studies showed that TM85 strongly binds to albumin. Studies carried out to study the formation of TM85 which adducts with ubiquitin and cytochrome c were performed by electrospray ionization mass spectrometry (ESI-MS). Antitumor activity was evaluated against a variety of human cancer cell lines, namely A2780, A2780cisR, MCF7, MDAMB231, HT29, PC3 and V79 non-tumorigenic cells and compared with the reference drug cisplatin. TM85 cytotoxic effect was reduced in the presence of endocytosis modulators at low temperatures, suggesting an energy-dependent mechanism consistent with endocytosis. Ultrastructural analysis by transmission electron microscopy (TEM) revealed that TM85 targets the endomembranar system disrupting the Golgi and also affects the mitochondria. Disruption of plasma membrane observed by flow cytometry could lead to cellular damage and cell death. On the whole, the biological activity evaluated herein combined with the water solubility property suggests that complex TM85 could be a promising anticancer agent. (C) 2013 Elsevier Inc. All rights reserved.

Complex variable positive definite functions

In this paper we develop an appropriate theory of positive definite functions on the complex plane from first principles and show some consequences of positive definiteness for meromorphic functions.

Positive radial solutions of the Dirichlet problem for the Minkowski-Curvature equation in a ball

We study the existence and multiplicity of positive radial solutions of the Dirichlet problem for the Minkowski-curvature equation { -div(del upsilon/root 1-vertical bar del upsilon vertical bar(2)) in B-R, upsilon=0 on partial derivative B-R,B- where B-R is a ball in R-N (N >= 2). According to the behaviour off = f (r, s) near s = 0, we prove the existence of either one, two or three positive solutions. All results are obtained by reduction to an equivalent non-singular one-dimensional problem, to which variational methods can be applied in a standard way.

Deep structure of crust and mantle beneath Iberia and Western Mediterranean from P and S Receiver functions and SKS Waveforms

We have conducted a P and S receiver functions [PRFs and SRFs] analysis for 19 seismic stations on the Iberia and western Mediterranean. In the transition zone [TZ] the PRFs analysis reveals a band [from Gibraltar to Balearic] increased by 10-20 km relative to the standard 250 km. The TZ thickness variations are strongly correlated with the P660s times in PRFs. We interpret the variable depth of the 660-km discontinuity as an effect of subduction. Over the anomalous TZ we found a reduced velocity zone in the upper mantle. Joint inversion of PRFs and SRFs reveals a subcrustal high S velocity lid and an underlying LVZ. A reduction of the S velocity in the LVZ is less than 10%. The Gutenberg discontinuity is located at 65±5 km, but in several models sampling the Mediterranean, the lid is missing or its thickness is reduced to ~30 km. In the Gibraltar and North Africa this boundary is located at ~100 km. The lid Vp/Vs beneath Betics is reduced relative to the standard 1.8. Another evidence of the Vp/Vs anomaly is provided by S410p phase late arrivals in the SRFs. The azimuthal anisotropy analysis with a new technology was conducted at 5 stations and at 2 groups of stations. The fast direction in the uppermost mantle layer is ~90º in Iberian Massif. In Balearic is in the azimuth of ~120º. At a depth of ~60 km the direction becomes 90º. Anisotropy in the upper layer can be interpreted as frozen, whereas anisotropy in the lower layer is active, corresponding to the present-day or recent flow. The effect of the asthenosphere in the SKS splitting is much larger than the effect of the subcrustal lithosphere.

Avaliação do potencial eólico para geração de energia eléctrica

Trabalho Final de Mestrado para a obtenção do grau de Mestre em Engenharia Mecânica /Energia

18F-FDG measurement in primary lung cancer: SUV normalization to different distribution volumes

Introduction: Standard Uptake Value (SUV) is a measurement of the uptake in a tumour normalized on the basis of a distribution volume and is used to quantify 18F-Fluorodeoxiglucose (FDG) uptake in tumors, such as primary lung tumor. Several sources of error can affect its accuracy. Normalization can be based on body weight, body surface area (BSA) and lean body mass (LBM). The aim of this study is to compare the influence of 3 normalization volumes in the calculation of SUV: body weight (SUVW), BSA (SUVBSA) and LBM (SUVLBM), with and without glucose correction, in patients with known primary lung tumor. The correlation between SUV and weight, height, blood glucose level, injected activity and time between injection and image acquisition is evaluated. Methods: Sample included 30 subjects (8 female and 22 male) with primary lung tumor, with clinical indication for 18F-FDG Positron Emission Tomography (PET). Images were acquired on a Siemens Biography according to the department’s protocol. Maximum pixel SUVW was obtained for abnormal uptake focus through semiautomatic VOI with Quantification 3D isocontour (threshold 2.5). The concentration of radioactivity (kBq/ml) was obtained from SUVW, SUVBSA, SUVLBM and the glucose corrected SUV were mathematically obtained. Results: Statistically significant differences between SUVW, SUVBSA and SUVLBM and between SUVWgluc, SUVBSAgluc and SUVLBMgluc were observed (p=0.000<0.05). The blood glucose level showed significant positive correlations with SUVW (r=0.371; p=0.043) and SUVLBM (r=0.389; p=0.034). SUVBSA showed independence of variations with the blood glucose level. Conclusion: The measurement of a radiopharmaceutical tumor uptake normalized on the basis of different distribution volumes is still variable. Further investigation on this subject is recommended.

Magnetic flux density distribution in the air gap of a ferromagnetic core with superconducting blocks: three-dimensional analysis and experimental NMR results

The design of magnetic cores can be carried out by taking into account the optimization of different parameters in accordance with the application requirements. Considering the specifications of the fast field cycling nuclear magnetic resonance (FFC-NMR) technique, the magnetic flux density distribution, at the sample insertion volume, is one of the core parameters that needs to be evaluated. Recently, it has been shown that the FFC-NMR magnets can be built on the basis of solenoid coils with ferromagnetic cores. Since this type of apparatus requires magnets with high magnetic flux density uniformity, a new type of magnet using a ferromagnetic core, copper coils, and superconducting blocks was designed with improved magnetic flux density distribution. In this paper, the designing aspects of the magnet are described and discussed with emphasis on the improvement of the magnetic flux density homogeneity (Delta B/B-0) in the air gap. The magnetic flux density distribution is analyzed based on 3-D simulations and NMR experimental results.