Isotope measurements from ODP Hole 104-642B

The Pliocene (5.3-2.6 Ma) is often described as a relatively stable climatic period, with warm temperatures characterizing high latitudes. New suborbital resolved stable isotope records from ODP Hole 642B in the Eastern Nordic Seas document that the Pliocene was not a stable period characterized by one climate. Rather, seven distinct climate phases, each lasting between 150,000 and 400,000 years, are identified and characterized in the time interval 5.1-3.1 Ma. Four of the transitions between the defined climate phases occurred close to an eccentricity minimum and a minimum in amplitude of change for Northern Hemisphere summer insolation, while two occurred around an eccentricity maximum and a maximum in amplitude in insolation change. Hence, a low frequency response of the Nordic Seas to insolation forcing is indicated. In addition, paleogeographic and related paleoceanographic changes, expansion of the Arctic sea ice cover and onset of NHG were important factors behind the evolving Pliocene low frequency variability in the eastern Nordic Seas. It is likely that the identified climate phases and transitions are important beyond the Nordic Seas, due to their association with changes to both insolation and paleogeography. Also, a strong and variable degree of diagenetic calcite overgrowth is documented for the planktic foraminifera, especially influencing the planktic d18O results; the absolute values and amplitude of change cannot be taken at face value.

Mecanismos de transmissão de preços e parcelas de mercado: uma análise sobre as exportações brasileiras de manga

Climate and environmental conditions allowed Brazil to become one of the largest producers of tropical fruits in the world. The São Francisco Valley, over the years, has emerged as the main fruit-producing region of the country, especially mangos and grapes. The mango, which is produced in this region, has reached a good international position, especially in European and American markets. However, the domestic price has absorbed more and more the impact of fluctuations in the international market expectations affecting the production and marketing of producers. The objective of the study is to analyze the transmission ratio of export prices of the mango, with the American market prices and the European Union in the period from 2003 to 2013. It is intended also to analyze the factors affecting the fluctuations of exports Brazilian mango for the main import markets. To achieve the proposed objectives, we used, in the methodology, the autoregressive vector model, in order to find the price transmission mechanism and the mechanisms of impacts through the impulse response function. We also used, the Constant Market Share model, in order to observe the importance of the effects competitiveness, destination, and growth in world trade on the changes of Brazilian mango exports in the period. The data used were obtained from the database of the Ministry of Development and Foreign Trade - MIDIC and FAOSTAT (Food and Agriculture Organization of the United Nations). Among the results, it was found that the Brazilian domestic prices are influenced by the US market price, and that price shocks promoted this market can impact on the growth of the internal prices for several months. It was noted also that the competitiveness effect accounted for the largest portion of the effective growth of Brazilian exports, in other word, the country has improved its competitiveness among the other exporting countries.

Spatial Relationships among Hydroacoustic, Hydrographic and Top Predator Patterns: Cetacean Distributions in the Mid-Atlantic Bight

Effective conservation and management of top predators requires a comprehensive understanding of their distributions and of the underlying biological and physical processes that affect these distributions. The Mid-Atlantic Bight shelf break system is a dynamic and productive region where at least 32 species of cetaceans have been recorded through various systematic and opportunistic marine mammal surveys from the 1970s through 2012. My dissertation characterizes the spatial distribution and habitat of cetaceans in the Mid-Atlantic Bight shelf break system by utilizing marine mammal line-transect survey data, synoptic multi-frequency active acoustic data, and fine-scale hydrographic data collected during the 2011 summer Atlantic Marine Assessment Program for Protected Species (AMAPPS) survey. Although studies describing cetacean habitat and distributions have been previously conducted in the Mid-Atlantic Bight, my research specifically focuses on the shelf break region to elucidate both the physical and biological processes that influence cetacean distribution patterns within this cetacean hotspot.

In Chapter One I review biologically important areas for cetaceans in the Atlantic waters of the United States. I describe the study area, the shelf break region of the Mid-Atlantic Bight, in terms of the general oceanography, productivity and biodiversity. According to recent habitat-based cetacean density models, the shelf break region is an area of high cetacean abundance and density, yet little research is directed at understanding the mechanisms that establish this region as a cetacean hotspot.

In Chapter Two I present the basic physical principles of sound in water and describe the methodology used to categorize opportunistically collected multi-frequency active acoustic data using frequency responses techniques. Frequency response classification methods are usually employed in conjunction with net-tow data, but the logistics of the 2011 AMAPPS survey did not allow for appropriate net-tow data to be collected. Biologically meaningful information can be extracted from acoustic scattering regions by comparing the frequency response curves of acoustic regions to theoretical curves of known scattering models. Using the five frequencies on the EK60 system (18, 38, 70, 120, and 200 kHz), three categories of scatterers were defined: fish-like (with swim bladder), nekton-like (e.g., euphausiids), and plankton-like (e.g., copepods). I also employed a multi-frequency acoustic categorization method using three frequencies (18, 38, and 120 kHz) that has been used in the Gulf of Maine and Georges Bank which is based the presence or absence of volume backscatter above a threshold. This method is more objective than the comparison of frequency response curves because it uses an established backscatter value for the threshold. By removing all data below the threshold, only strong scattering information is retained.

In Chapter Three I analyze the distribution of the categorized acoustic regions of interest during the daytime cross shelf transects. Over all transects, plankton-like acoustic regions of interest were detected most frequently, followed by fish-like acoustic regions and then nekton-like acoustic regions. Plankton-like detections were the only significantly different acoustic detections per kilometer, although nekton-like detections were only slightly not significant. Using the threshold categorization method by Jech and Michaels (2006) provides a more conservative and discrete detection of acoustic scatterers and allows me to retrieve backscatter values along transects in areas that have been categorized. This provides continuous data values that can be integrated at discrete spatial increments for wavelet analysis. Wavelet analysis indicates significant spatial scales of interest for fish-like and nekton-like acoustic backscatter range from one to four kilometers and vary among transects.

In Chapter Four I analyze the fine scale distribution of cetaceans in the shelf break system of the Mid-Atlantic Bight using corrected sightings per trackline region, classification trees, multidimensional scaling, and random forest analysis. I describe habitat for common dolphins, Risso’s dolphins and sperm whales. From the distribution of cetacean sightings, patterns of habitat start to emerge: within the shelf break region of the Mid-Atlantic Bight, common dolphins were sighted more prevalently over the shelf while sperm whales were more frequently found in the deep waters offshore and Risso’s dolphins were most prevalent at the shelf break. Multidimensional scaling presents clear environmental separation among common dolphins and Risso’s dolphins and sperm whales. The sperm whale random forest habitat model had the lowest misclassification error (0.30) and the Risso’s dolphin random forest habitat model had the greatest misclassification error (0.37). Shallow water depth (less than 148 meters) was the primary variable selected in the classification model for common dolphin habitat. Distance to surface density fronts and surface temperature fronts were the primary variables selected in the classification models to describe Risso’s dolphin habitat and sperm whale habitat respectively. When mapped back into geographic space, these three cetacean species occupy different fine-scale habitats within the dynamic Mid-Atlantic Bight shelf break system.

In Chapter Five I present a summary of the previous chapters and present potential analytical steps to address ecological questions pertaining the dynamic shelf break region. Taken together, the results of my dissertation demonstrate the use of opportunistically collected data in ecosystem studies; emphasize the need to incorporate middle trophic level data and oceanographic features into cetacean habitat models; and emphasize the importance of developing more mechanistic understanding of dynamic ecosystems.

Evaluación de la calidad de un servicio de voluntariado en oncología: un Análisis Importancia-Valoración (IPA)

Objective: Using an Importance-Performance Analysis (IPA), this paper examined a Radiotherapy and Oncological Patient and Non-patient perceived importance and performance of ten Humanization Volunteer Program selection factors in the General Hospital in Spain.Methods: The authors identified a list of seven items from the Health-marketing literature reviews, and each item was rated using a 5-point Likert scale. Responses were obtained of 148 usable interviews.Results: The importance-performance patient grid was corrected with literature recommendations and, in the patient sample, shows three items fall in the “Keep up the good work” quadrant, four items fall into the “Low priority” quadrant, zero items fall into the “Possible overkill” quadrant, and no items fall in the “Concentrate here” quadrant. Non-patient (n=80) factors means shows statistical differences with patient (n=68) means in catering (t=-2.38; df.=146; p<0.05), and information (t=2.16; df146; p<0,05).Conclusions: The results are useful in identifying areas for strategic focus to help Health Services managers develop humanization programs with volunteer workers and different program users. Implication to volunteer programs managers and researchers were discussed.

On the Nature of Temporal Variability of the Gulf Stream Path from 75° to 55°W

The response of the Gulf Stream (GS) system to atmospheric forcing is generally linked either to the basin-scale winds on the subtropical gyre or to the buoyancy forcing from the Labrador Sea. This study presents a multiscale synergistic perspective to describe the low-frequency response of the GS system. The authors identify dominant temporal variability in the North Atlantic Oscillation (NAO), in known indices of the GS path, and in the observed GS latitudes along its path derived from sea surface height (SSH) contours over the period 1993-2013. The analysis suggests that the signature of interannual variability changes along the stream's path from 75 degrees to 55 degrees W. From its separation at Cape Hatteras to the west of 65 degrees W, the variability of the GS is mainly in the near-decadal (7-10 years) band, which is missing to the east of 60 degrees W, where a new interannual (4-5 years) band peaks. The latter peak (4-5 years) was missing to the west of 65 degrees W. The region between 65 degrees and 60 degrees W seems to be a transition region. A 2-3-yr secondary peak was pervasive in all time series, including that for the NAO. This multiscale response of the GS system is supported by results from a basin-scale North Atlantic model. The near-decadal response can be attributed to similar forcing periods in the NAO signal; however, the interannual variability of 4-5 years in the eastern segment of the GS path is as yet unexplained. More numerical and observational studies are warranted to understand such causality.

On the Nature of Temporal Variability of the Gulf Stream Path from 75° to 55°W

The response of the Gulf Stream (GS) system to atmospheric forcing is generally linked either to the basin-scale winds on the subtropical gyre or to the buoyancy forcing from the Labrador Sea. This study presents a multiscale synergistic perspective to describe the low-frequency response of the GS system. The authors identify dominant temporal variability in the North Atlantic Oscillation (NAO), in known indices of the GS path, and in the observed GS latitudes along its path derived from sea surface height (SSH) contours over the period 1993-2013. The analysis suggests that the signature of interannual variability changes along the stream's path from 75 degrees to 55 degrees W. From its separation at Cape Hatteras to the west of 65 degrees W, the variability of the GS is mainly in the near-decadal (7-10 years) band, which is missing to the east of 60 degrees W, where a new interannual (4-5 years) band peaks. The latter peak (4-5 years) was missing to the west of 65 degrees W. The region between 65 degrees and 60 degrees W seems to be a transition region. A 2-3-yr secondary peak was pervasive in all time series, including that for the NAO. This multiscale response of the GS system is supported by results from a basin-scale North Atlantic model. The near-decadal response can be attributed to similar forcing periods in the NAO signal; however, the interannual variability of 4-5 years in the eastern segment of the GS path is as yet unexplained. More numerical and observational studies are warranted to understand such causality.

Hajautetun automaation käyttö osana simulaatiota

Työssä perehdytään simulaatiotekniikkaan, jossa käytetään osana fyysistä laitteistoa, ja siihen tarvittaviin komponentteihin, kuten ohjelmistorajapintoihin sekä kenttäväylään. Työssä tutustutaan myös IEC 61131-3 ja IEC 61499 -standardien mukaisiin toimintolohkomalleihin, joita käytetään automaatiossa. Näiden perusteella kehitetään järjestelmä, jonka avulla Simulink-ympäristössä voidaan oman toimintolohkon avulla käyttää taajuusmuuttajaa osana simulaatiota. Tällaisen reaaliaikaisen systeemin eri osien väliseen synkronointiin kiinnitetään myös huomiota. Järjestelmää testataan simulaatiomallilla, jossa syötetään vääntömomenttiohje taajuusmuuttajalle, joka mittaa siihen kytketyn moottorin pyörimisnopeuden. Mallilla voidaan esimerkiksi arvioida kuorman hitausmomentti. Työssä tutustutaan myös taajuusmuuttajien ohjelmallisiin ominaisuuksiin ja niiden perusteella pohditaan esitetyn kaltaisten järjestelmien käyttöä hajautettuna automaatiojärjestelmänä. Kokeellinen työ tehtiin säätö- ja digitaalitekniikan laboratoriossa vuoden 2010 aikana.

Modélisation des machines par circuits couplés pour l’observation des courants de barres au rotor

Ce travail présente une modélisation rapide d’ordre élévé capable de modéliser une configuration rotorique en cage complète ou en grille, de reproduire les courants de barre et tenir compte des harmoniques d’espace. Le modèle utilise une approche combinée d’éléments finis avec les circuits-couplés. En effet, le calcul des inductances est réalisé avec les éléments finis, ce qui confère une précision avancée au modèle. Cette méthode offre un gain important en temps de calcul sur les éléments finis pour des simulations transitoires. Deux outils de simulation sont développés, un dans le domaine du temps pour des résolutions dynamiques et un autre dans le domaine des phaseurs dont une application sur des tests de réponse en fréquence à l’arrêt (SSFR) est également présentée. La méthode de construction du modèle est décrite en détail de même que la procédure de modélisation de la cage du rotor. Le modèle est validé par l’étude de machines synchrones: une machine de laboratoire de 5.4 KVA et un grand alternateur de 109 MVA dont les mesures expérimentales sont comparées aux résultats de simulation du modèle pour des essais tels que des tests à vide, des courts-circuits triphasés, biphasés et un test en charge.

An Acoustic Analysis of Valveless Pulsejet Engines

Valveless pulsejets are extremely simple aircraft engines; essentially cleverly designed tubes with no moving parts. These engines utilize pressure waves, instead of machinery, for thrust generation, and have demonstrated thrust-to-weight ratios over 8 and thrust specific fuel consumption levels below 1 lbm/lbf-hr – performance levels that can rival many gas turbines. Despite their simplicity and competitive performance, they have not seen widespread application due to extremely high noise and vibration levels, which have persisted as an unresolved challenge primarily due to a lack of fundamental insight into the operation of these engines. This thesis develops two theories for pulsejet operation (both based on electro-acoustic analogies) that predict measurements better than any previous theory reported in the literature, and then uses them to devise and experimentally validate effective noise reduction strategies. The first theory analyzes valveless pulsejets as acoustic ducts with axially varying area and temperature. An electro-acoustic analogy is used to calculate longitudinal mode frequencies and shapes for prescribed area and temperature distributions inside an engine. Predicted operating frequencies match experimental values to within 6% with the use of appropriate end corrections. Mode shapes are predicted and used to develop strategies for suppressing higher modes that are responsible for much of the perceived noise. These strategies are verified experimentally and via comparison to existing models/data for valveless pulsejets in the literature. The second theory analyzes valveless pulsejets as acoustic systems/circuits in which each engine component is represented by an acoustic impedance. These are assembled to form an equivalent circuit for the engine that is solved to find the frequency response. The theory is used to predict the behavior of two interacting pulsejet engines. It is validated via comparison to experiment and data in the literature. The technique is then used to develop and experimentally verify a method for operating two engines in anti-phase without interfering with thrust production. Finally, Helmholtz resonators are used to suppress higher order modes that inhibit noise suppression via anti-phasing. Experiments show that the acoustic output of two resonator-equipped pulsejets operating in anti-phase is 9 dBA less than the acoustic output of a single pulsejet.

Acousto-optic modulation of optical reflection properties in fiber Bragg gratings and the application in fiber lasers

This thesis aims to investigate the interaction of acoustic waves and fiber Bragg gratings (FBGs) in standard and suspended-core fibers (SCFs), to evaluate the influence of the fiber, grating and modulator design on the increase of the modulation efficiency, bandwidth and frequency. Initially, the frequency response and the resonant acoustic modes of a low frequency acousto-optic modulator (f < 1.2 MHz) are numerically investigated by using the finite element method. Later, the interaction of longitudinal acoustic waves and FBGs in SCFs is also numerically investigated. The fiber geometric parameters are varied and the strain and grating properties are simulated by means of the finite element method and the transfer matrix method. The study indicates that the air holes composing the SCF cause a significant reduction of the amount of silica in the fiber cross section increasing acousto-optic interaction in the core. Experimental modulation of the reflectivity of FBGs inscribed in two distinct SCFs indicates evidences of this increased interaction. Besides, a method to acoustically induce a dynamic phase-shift in a chirped FBG employing an optimized design of modulator is shown. Afterwards, a combination of this modulator and a FBG inscribed in a three air holes SCF is applied to mode-lock an ytterbium doped fiber laser. To improve the modulator design for future applications, two other distinct devices are investigated to increase the acousto-optic interaction, bandwidth and frequency (f > 10 MHz). A high reflectivity modulation has been achieved for a modulator based on a tapered fiber. Moreover, an increased modulated bandwidth (320 pm) has been obtained for a modulator based on interaction of a radial long period grating (RLPG) and a FBG inscribed in a standard fiber. In summary, the results show a considerable reduction of the grating/fiber length and the modulator size, indicating possibilities for compact and faster acousto-optic fiber devices. Additionally, the increased interaction efficiency, modulated bandwidth and frequency can be useful to shorten the pulse width of future all-fiber mode-locked fiber lasers, as well, to other photonic devices which require the control of the light in optical fibers by electrically tunable acoustic waves.

Desenvolvimento de uma bancada para a realização de ensaios de auto-amortecimento em cabos condutores de energia elétrica

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.

Predicting Plant Performance Under Simultaneously Changing Environmental Conditions-The Interplay Between Temperature, Light, and Internode Growth

Plant performance is significantly influenced by prevailing light and temperature conditions during plant growth and development. For plants exposed to natural fluctuations in abiotic environmental conditions it is however laborious and cumbersome to experimentally assign any contribution of individual environmental factors to plant responses. This study aimed at analyzing the interplay between light, temperature and internode growth based on model approaches. We extended the light-sensitive virtual plant model L-Cucumber by implementing a common Arrhenius function for appearance rates, growth rates, and growth durations. For two greenhouse experiments, the temperature-sensitive model approach resulted in a precise prediction of cucumber mean internode lengths and number of internodes, as well as in accurately predicted patterns of individual internode lengths along the main stem. In addition, a system's analysis revealed that environmental data averaged over the experimental period were not necessarily related to internode performance. Finally, the need for a species-specific parameterization of the temperature response function and related aspects in modeling temperature effects on plant development and growth is discussed.

Parcellation of fMRI datasets with ICA and PLS: a data driven approach

Inter-subject parcellation of functional Magnetic Resonance Imaging (fMRI) data based on a standard General Linear Model (GLM) and spectral clustering was recently proposed as a means to alleviate the issues associated with spatial normalization in fMRI. However, for all its appeal, a GLM-based parcellation approach introduces its own biases, in the form of a priori knowledge about the shape of Hemodynamic Response Function (HRF) and task-related signal changes, or about the subject behaviour during the task. In this paper, we introduce a data-driven version of the spectral clustering parcellation, based on Independent Component Analysis (ICA) and Partial Least Squares (PLS) instead of the GLM. First, a number of independent components are automatically selected. Seed voxels are then obtained from the associated ICA maps and we compute the PLS latent variables between the fMRI signal of the seed voxels (which covers regional variations of the HRF) and the principal components of the signal across all voxels. Finally, we parcellate all subjects data with a spectral clustering of the PLS latent variables. We present results of the application of the proposed method on both single-subject and multi-subject fMRI datasets. Preliminary experimental results, evaluated with intra-parcel variance of GLM t-values and PLS derived t-values, indicate that this data-driven approach offers improvement in terms of parcellation accuracy over GLM based techniques.

Electrical characterization of electronic circuits produced by inkjet printing

Dissertação de Mestrado, Engenharia Electrónica e Telecomunicações, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Extração de metais (K, Mg, Ba, Ca, Cr, Mn, Li, Fe) de água produzida utilizando sistema microemulsionado

The produced water is a byproduct formed due to production of petroleum and carries with it a high amount of contaminants such as oil particles in suspension, organic compounds and metals. Thus, these latter pollutants are very difficult to treat because of its high solubility in water. The objective of this work is to use and evaluate a microemulsioned system to remove metals ( K , Mg , Ba , Ca , Cr , Mn , Li , Fe ) of synthetic produced water. For the extraction of metals, it was used a pseudoternary diagram containing the following phases: synthetic produced water as the aqueous phase (AP), hexane as organic phase (OP), and a cosurfactant/surfactant ratio equal to four (C/S = 4) as the third phase, where the OCS (saponified coconut oil) was used as surfactant and n-butanol as cosurfactant. The synthetic produced water was prepared in a bench scale and the region of interest in the diagram for the removal of metals was determined by experimental design called. Ten points located in the phase Winsor II were selected in an area with a large amount of water and small amounts of reagents. The samples were analyzed in atomic absorption spectrometer, and the results were evaluated through a statistical assesment, allowing the efficiency analysis of the effects and their interactions. The results showed percentages of extraction above 90% for the metals manganese, iron, chromium, calcium, barium and magnesium, and around 45% for metals lithium and potassium. The optimal point for the simultaneous removal of metals was calculated using statistical artifact multiple response function (MR). This calculation showed that the point of greatest extraction of metals occurs was the J point, with the composition [72% AP, 9% OP, 19% C/S], obtaining a global extraction percentage about 80%. Considering the aspects analyzed, the microemulsioned system has shown itself to be an effective alternative in the extraction of metals on synthetic produced water remediation