Hydrochemical variability at the Upper Paraguay Basin and Pantanal wetland

Compartmentalization is a prerequisite to understand large wetlands that receive water from several sources. However, it faces the heterogeneity in space and time, resulting from physical, chemical and biological processes that are specific to wetlands. The Pantanal is a vast seasonally flooded continental wetland located in the centre of South America. The chemical composition of the waters that supply the Pantanal (70 rivers) has been studied in order to establish a compartmentalization of the wetland based on soil-water interactions. A PCA-based EMMA (End-Members Mixing Analysis) procedure shows that the chemistry of the rivers can be viewed as a mixture of 3 end-members, influenced by lithology and land use, and delimiting large regions. Although the chemical composition of the end-members changed between dry and wet seasons, their spatial distribution was maintained. The results were extended to the floodplain by simple tributary mixing calculation according to the hydrographical network and to the areas of influence for each river when in overflow conditions. The resulting map highlights areas of high geochemical contrast on either side of the river Cuiaba in the north, and of the rivers Aquidauana and Abobral in the south. The PCA-based treatment on a sampling conducted in the Nhecolandia, a large sub region of the Pantanal, allowed the identification and ordering of the processes that control the geochemical variability of the surface waters. Despite an enormous variability in electrical conductivity and pH, all data collected were in agreement with an evaporation process of the Taquari River water, which supplies the region. Evaporation and associated saline precipitations (Mg-calcite, Mg-silicates K-silicates) explained more than 77% of the total variability in the chemistry of the regional surface water sampling.

Shear force and torsion in reinforced concrete beam elements: theoretical analysis based on Brazilian Standard Code ABNT NBR 6118:2007

Reinforced concrete beam elements are submitted to applicable loads along their life cycle that cause shear and torsion. These elements may be subject to only shear, pure torsion or both, torsion and shear combined. The Brazilian Standard Code ABNT NBR 6118:2007 [1] fixes conditions to calculate the transverse reinforcement area in beam reinforced concrete elements, using two design models, based on the strut and tie analogy model, first studied by Mörsch [2]. The strut angle θ (theta) can be considered constant and equal to 45º (Model I), or varying between 30º and 45º (Model II). In the case of transversal ties (stirrups), the variation of angle α (alpha) is between 45º and 90º. When the equilibrium torsion is required, a resistant model based on space truss with hollow section is considered. The space truss admits an inclination angle θ between 30º and 45º, in accordance with beam elements subjected to shear. This paper presents a theoretical study of models I and II for combined shear and torsion, in which ranges the geometry and intensity of action in reinforced concrete beams, aimed to verify the consumption of transverse reinforcement in accordance with the calculation model adopted As the strut angle on model II ranges from 30º to 45º, transverse reinforcement area (Asw) decreases, and total reinforcement area, which includes longitudinal torsion reinforcement (Asℓ), increases. It appears that, when considering model II with strut angle above 40º, under shear only, transverse reinforcement area increases 22% compared to values obtained using model I.

Improved Space Object Orbit Determination Using CMOS Detectors

CMOS-sensors, or in general Active Pixel Sensors (APS), are rapidly replacing CCDs in the consumer camera market. Due to significant technological advances during the past years these devices start to compete with CCDs also for demanding scientific imaging applications, in particular in the astronomy community. CMOS detectors offer a series of inherent advantages compared to CCDs, due to the structure of their basic pixel cells, which each contains their own amplifier and readout electronics. The most prominent advantages for space object observations are the extremely fast and flexible readout capabilities, feasibility for electronic shuttering and precise epoch registration,and the potential to perform image processing operations on-chip and in real-time. Here, the major challenges and design drivers for ground-based and space-based optical observation strategies for objects in Earth orbit have been analyzed. CMOS detector characteristics were critically evaluated and compared with the established CCD technology, especially with respect to the above mentioned observations. Finally, we simulated several observation scenarios for ground- and space-based sensor by assuming different observation and sensor properties. We will introduce the analyzed end-to-end simulations of the ground- and spacebased strategies in order to investigate the orbit determination accuracy and its sensitivity which may result from different values for the frame-rate, pixel scale, astrometric and epoch registration accuracies. Two cases were simulated, a survey assuming a ground-based sensor to observe objects in LEO for surveillance applications, and a statistical survey with a space-based sensor orbiting in LEO observing small-size debris in LEO. The ground-based LEO survey uses a dynamical fence close to the Earth shadow a few hours after sunset. For the space-based scenario a sensor in a sun-synchronous LEO orbit, always pointing in the anti-sun direction to achieve optimum illumination conditions for small LEO debris was simulated.

Space management and the courts : a summary /

"This summary is based on Space Management and the Courts.-- Design Handbook prepared under Grant Nos. NI 70-040 and NI 71-059 from the National Institute of Law Enforcement and Criminal Justice ... "

The application of PCA as a movement pattern recognition technique: A proof of principle

Quantitative methods can help us understand how underlying attributes contribute to movement patterns. Applying principal components analysis (PCA) to whole-body motion data may provide an objective data-driven method to identify unique and statistically important movement patterns. Therefore, the primary purpose of this study was to determine if athletes’ movement patterns can be differentiated based on skill level or sport played using PCA. Motion capture data from 542 athletes performing three sport-screening movements (i.e. bird-dog, drop jump, T-balance) were analyzed. A PCA-based pattern recognition technique was used to analyze the data. Prior to analyzing the effects of skill level or sport on movement patterns, methodological considerations related to motion analysis reference coordinate system were assessed. All analyses were addressed as case-studies. For the first case study, referencing motion data to a global (lab-based) coordinate system compared to a local (segment-based) coordinate system affected the ability to interpret important movement features. Furthermore, for the second case study, where the interpretability of PCs was assessed when data were referenced to a stationary versus a moving segment-based coordinate system, PCs were more interpretable when data were referenced to a stationary coordinate system for both the bird-dog and T-balance task. As a result of the findings from case study 1 and 2, only stationary segment-based coordinate systems were used in cases 3 and 4. During the bird-dog task, elite athletes had significantly lower scores compared to recreational athletes for principal component (PC) 1. For the T-balance movement, elite athletes had significantly lower scores compared to recreational athletes for PC 2. In both analyses the lower scores in elite athletes represented a greater range of motion. Finally, case study 4 reported differences in athletes’ movement patterns who competed in different sports, and significant differences in technique were detected during the bird-dog task. Through these case studies, this thesis highlights the feasibility of applying PCA as a movement pattern recognition technique in athletes. Future research can build on this proof-of-principle work to develop robust quantitative methods to help us better understand how underlying attributes (e.g. height, sex, ability, injury history, training type) contribute to performance.

Hydrometeor and latent heat profiles of tropical cyclones Conson, Ivan and Catarina using PR/TRMM data

ABSTRACT Microphysical and thermodynamical features of two tropical systems, namely Hurricane Ivan and Typhoon Conson, and one sub-tropical, Catarina, have been analyzed based on space-born radar PR measurements available on the TRMM satellite. The procedure to classify the reflectivity profiles followed the Heymsfield et al (2000) and Steiner et al (1995) methodologies. The water and ice content have been calculated using a relationship obtained with data of the surface SPOL radar and PR in Rondonia State in Brazil. The diabatic heating rate due to latent heat release has been estimated using the methodology developed by Tao et al (1990). A more detailed analysis has been performed for Hurricane Catarina, the first of its kind in South Atlantic. High water content mean value has been found in Conson and Ivan at low levels and close to their centers. Results indicate that hurricane Catarina was shallower than the other two systems, with less water and the water was concentrated closer to its center. The mean ice content in Catarina was about 0.05 g kg-1 while in Conson it was 0.06 g kg-1 and in Ivan 0.08 g kg-1. Conson and Ivan had water content up to 0.3 g kg-1 above the 0ºC layer, while Catarina had less than 0.15 g kg-1. The latent heat released by Catarina showed to be very similar to the other two systems, except in the regions closer to the center.

Proper motions of thermally emitting isolated neutron stars measured with Chandra

The remarkable astrometric capabilities of the Chandra Observatory offer the possibility to measure proper motions of X-ray sources with an unprecedented accuracy in this wavelength range. We recently completed a proper motion survey of three of the seven thermally emitting radio-quiet isolated neutron stars (INSs) discovered in the ROSAT all-sky survey. These INSs (RXJ0420.0-5022, RXJ0806.4-4123 and RXJ1308.6+2127) either lack an optical counterpart or have one so faint that ground based or space born optical observations push the current possibilities of the instrumentation to the limit. Pairs of ACIS observations were acquired 3 to 5 years apart to measure the displacement of the sources on the X-ray sky using as a reference the background of extragalactic or remote Galactic X-ray sources. We derive 2 sigma upper limits of 123 mas yr(-1) and 86 mas yr(-1) on the proper motion of RXJ0420.0-5022 and RXJ0806.4-4123, respectively. RXJ1308.6+2127 exhibits a very significant displacement (similar to 9 sigma) yielding mu = 220 +/- 25 mas yr(-1), the second fastest measured among all ROSAT-discovered INSs. The source is probably moving away rapidly from the Galactic plane at a speed which precludes any significant accretion of matter from the interstellar medium. Its transverse velocity of similar to 740 (d/700 pc) km s(-1) might be the largest of all ROSAT INSs and its corresponding spatial velocity lies among the fastest recorded for neutron stars. RXJ1308.6+2127 is thus a middle-aged (age similar to 1 My) high velocity cooling neutron star. We investigate its possible origin in nearby OB associations or from a field OB star. In most cases, the flight time from birth place appears significantly shorter than the characteristic age derived from spin down rate. Overall, the distribution in transverse velocity of the ROSAT INSs is not statistically different from that of normal radio pulsars.

Classificação automática de textos baseada em ontologias

Dissertação de Mestrado em Engenharia Informática

Microtheories for SDI - Accounting for diversity of local conceptualisations at a global level

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Detecció i localització d'impactes a estructures aeroespacials

Projecte de recerca elaborat a partir d’una estada a la Universidad Politécnica de Madrid, Espanya, entre setembre i o desembre del 2007. Actualment la indústria aeroespacial i aeronàutica té com prioritat millorar la fiabilitat de las seves estructures a través del desenvolupament de nous sistemes per a la monitorització i detecció d’impactes. Hi ha diverses tècniques potencialment útils, i la seva aplicabilitat en una situació particular depèn críticament de la mida del defecte que permet l’estructura. Qualsevol defecte canviarà la resposta vibratòria de l’element estructural, així com el transitori de l’ona que es propaga per l’estructura elàstica. Correlacionar aquests canvis, que poden ser detectats experimentalment amb l’ocurrència del defecte, la seva localització i quantificació, és un problema molt complex. Aquest treball explora l’ús de l'Anàlisis de Components Principals (Principal Component Analysis - PCA-) basat en la formulació dels estadístics T2 i Q per tal de detectar i distingir els defectes a l'estructura, tot correlacionant els seus canvis a la resposta vibratòria. L’estructura utilitzada per l’estudi és l’ala d’una turbina d’un avió comercial. Aquesta ala s’excita en un extrem utilitzant un vibrador, i a la qual s'han adherit set sensors PZT a la superfície. S'aplica un senyal conegut i s'analitzen les respostes. Es construeix un model PCA utilitzant dades de l’estructura sense defecte. Per tal de provar el model, s'adhereix un tros d’alumini en quatre posicions diferents. Les dades dels assajos de l'estructura amb defecte es projecten sobre el model. Les components principals i les distàncies de Q-residual i T2-Hotelling s'utilitzaran per a l'anàlisi de les incidències. Q-residual indica com de bé s'adiu cadascuna de les mostres al model PCA, ja que és una mesura de la diferència, o residu, entre la mostra i la seva projecció sobre les components principals retingudes en el model. La distància T2-Hotelling és una mesura de la variació de cada mostra dins del model PCA, o el que vindria a ser el mateix, la distància al centre del model PCA.

A statistical shape model of the human second cervical vertebra.

PURPOSE: Statistical shape and appearance models play an important role in reducing the segmentation processing time of a vertebra and in improving results for 3D model development. Here, we describe the different steps in generating a statistical shape model (SSM) of the second cervical vertebra (C2) and provide the shape model for general use by the scientific community. The main difficulties in its construction are the morphological complexity of the C2 and its variability in the population. METHODS: The input dataset is composed of manually segmented anonymized patient computerized tomography (CT) scans. The alignment of the different datasets is done with the procrustes alignment on surface models, and then, the registration is cast as a model-fitting problem using a Gaussian process. A principal component analysis (PCA)-based model is generated which includes the variability of the C2. RESULTS: The SSM was generated using 92 CT scans. The resulting SSM was evaluated for specificity, compactness and generalization ability. The SSM of the C2 is freely available to the scientific community in Slicer (an open source software for image analysis and scientific visualization) with a module created to visualize the SSM using Statismo, a framework for statistical shape modeling. CONCLUSION: The SSM of the vertebra allows the shape variability of the C2 to be represented. Moreover, the SSM will enable semi-automatic segmentation and 3D model generation of the vertebra, which would greatly benefit surgery planning.

Development of racemization catalysts for dynamic kinetic resolution

Preparation of optically active compounds is of high importance in modern medicinal chemistry. Despite recent advances in the field of asymmetric synthesis, resolution of racemates still remains the most utilized way for preparation of single enantiomers in industrial scale due to its cost-efficiency and simplicity. Enzymatic kinetic resolution (KR) of racemates is a classical method for separation of enantiomers. One of its drawbacks is the limitation of target enantiomer yield to 50%. Dynamic Kinetic Resolution (DKR) allows to reach yields up to 100% by in situ racemization of the less reactive enantiomer. In the first part of this thesis, a number of half-sandwich ruthenium complexes were prepared and evaluated as catalysts for racemization of optically active secondary alcohols. A leading catalyst, Bn5CpRu(CO)2Cl, was identified. The catalyst discovered was extensively characterized by its application for DKR of a broad range of secondary alcohols in a wide range of reaction loadings (1 mmol – 1 mol). Cost-efficient chromatography-free procedure for preparation of this catalyst was developed. Further, detailed kinetic and mechanistic studies of the racemization reactions were performed. Comparison of racemization rates in the presence of Bn5CpRu(CO)2Cl and Ph5CpRu(CO)2Cl catalysts reveals that the performance of the catalytic system can be adjusted by matching of the electronic properties of the catalysts and the substrates. Moreover, dependence of the rate-limiting step from the electronic properties of the reagents was observed. Important conclusions about reaction mechanism were made. Finally, an alternative approach to DKR of amines based on space separated vessels was addressed. This procedure allows the combination of thermolabile enzyme with racemization catalysts active only at high temperatures.

Evaluation of a stage II screening protocol for prostate cancer

In 2003, prostate cancer (PCa) is estimated to be the most commonly diagnosed cancer and third leading cause of cancer death in Canada. During PCa population screening, approximately 25% of patients with a normal digital rectal examination (DRE) and intermediate serum prostate specific antigen (PSA) level have PCa. Since all patients typically undergo biopsy, it is expected that approximately 75% of these procedures are unnecessary. The purpose of this study was to compare the degree of efficacy of clinical tests and algorithms in stage II screening for PCa while preventing unnecessary biopsies from occurring. The sample consisted of 201 consecutive men who were suspected of PCa based on the results of a DRE and serum PSA. These men were referred for venipuncture and transrectal ultrasound (TRUS). Clinical tests included TRUS, agespecific reference range PSA (Age-PSA), prostate specific antigen density (PSAD), and free-to-total prostate specific antigen ratio (%fPSA). Clinical results were evaluated individually and within algorithms. Cutoffs of 0.12 and 0.15 ng/ml/cc were employed for PSAD. Cutoffs that would provide a minimum sensitivity of 0.90 and 0.95, respectively were utilized for %fPSA. Statistical analysis included ROC curve analysis, calculated sensitivity (Sens), specificity (Spec), and positive likelihood ratio (LR), with corresponding confidence intervals (Cl). The %fPSA, at a 23% cutoff ({ Sens=0.92; CI, 0.06}, {Spec=0.4l; CI, 0.09}, {LR=1.56; CI, O.ll}), proved to be the most efficacious independent clinical test. The combination of PSAD (cutoff 0.15 ng/ml/cc) and %fPSA (cutoff 23%) ({Sens=0.93; CI, 0.06}, {Spec=0.38; CI, 0.08}, {LR=1.50; CI, 0.10}) was the most efficacious clinical algorithm. This study advocates the use of %fPSA at a cutoff of 23% when screening patients with an intermediate serum PSA and benign DRE.

Étude de la dynamique des interactions des constituants du complexe de biosynthèse et d’insertion de la sélénocystéine dans la traduction des sélénoprotéines in vivo

Les sélénoprotéines sont des protéines auxquelles des sélénocystéines, soit le 21e acide aminé, sont incorporées durant leur traduction. Plus précisément, la sélénocystéine (Sec) est un dérivé métabolique de la sérine, mais structurellement équivalent à une cystéine dont on a remplacé l'atome de soufre par du sélénium. Elle se distingue des autres acides aminés puisqu’elle possède sa propre synthétase qui sert à convertir la sérine en Sec alors que le résidu est déjà fixé à l’ARNt. La position d’une Sec sur l’ARNm est indiquée par le codon UGA étant habituellement un signal STOP introduisant le concept de recoding. Grâce à une machinerie métabolique spécifique à l'ARNtSec et à la présence d’un SecIS (Selenocystein Insertion Sequence) sur l’ARNm, ce codon permet la présence d'une Sec dans la protéine. Il est connu que la synthèse débute avec l’acétylation de l’ARNt[Ser]Sec par la seryl-ARNt synthétase (SerRS) afin de donner la seryl-ARNt[Ser]Sec. Cette dernière est subséquemment phosphorylée par l’O-phosphoséryl-ARNt[Ser]Sec kinase (PSTK) qui donnera l’O-phosphoséryl-ARNt[Ser]Sec. Par la suite, un complexe de plusieurs protéines et cofacteurs, agissant comme machinerie pour l’incorporation des Sec durant la traduction, s’associe avec l’ARNt[Ser]Sec puis l’ARNm et, finalement, les composantes du ribosome. Parmi ces protéines, SepSecS catalyse l’étape finale de la synthèse des Sec en convertissant le O-phosphoseryl-ARNt[Ser]Sec en selenocysteinyl-ARNt[Ser]Sec utilisant le sélénophosphate comme source de sélénium. Des études récentes montrent que l’association avec SECp43 serait nécessaire pour que SepSecS joue son rôle et soit ségrégée au noyau pour s’associer à la machinerie de biosynthèse des sélénoprotéines, soit le complexe moléculaire qui reconnaît le codon UGA. Parmi les protéines de la machinerie de biosynthèse des sélénoprotéines que nous avons analysées, il y a eEFSec, RPL30, SPS2, SPS1, SBP2 et NSEP1. Nos résultats d’analyse de la dynamique de l’interaction entre les constituants de la machinerie de biosynthèse et d’incorporation des Sec, confirment plusieurs données de la littérature, mais remettent en question le modèle jusqu’à maintenant établi. Une meilleure compréhension de la dynamique des interactions entre ses constituants et la régulation de cette dynamique permet d’émettre des hypothèses quant au rôle de la machinerie de biosynthèse des sélénoprotéines et de l’importance de sa complexité. Nous avons analysé les interactions in vivo dans des cellules HEK293T au moyen de la technique de Protein-Fragment Complementation Assay (PCA) en couplant, par un clonage moléculaire, les gènes de chacune des protéines d’intérêt avec des fragments des gènes de la protéine luciférase (hRluc). Nous avons ainsi réalisé une fusion en N-terminal et en C-terminal des fragments de luciférase pour chacune des protéines d’intérêt. Puis, nous avons analysé la dynamique des interactions avec les composantes de la machinerie de biosynthèse des Sec. D’autres travaux seront essentiels afin de bâtir sur les résultats présentés dans cette recherche.