Evaluating the environmental Kuznets curve

We examine the empirical evidence for an environmental Kuznets curve using a semiparametric smooth coefficient regression model that allows us to incorporate flexibility in the parameter estimates, while maintaining the basic econometric structure that is typically used to estimate the pollution-income relationship. This allows us to assess the sensitivity to parameter heterogeneity of typical parametric models used to estimate the relationship between pollution and income, as well as identify why the results from such models are seldom found to be robust. Our results confirm that the resulting relationship between pollution and income is fragile; we show that the estimated pollution-income relationship depends substantially on the heterogeneity of the slope coefficients and the parameter values at which the relationship is evaluated. Different sets of parameters obtained from the semiparametric model give rise to many different shapes for the pollution-income relationship that are commonly found in the literature.

3D simulation of the effects of sphericity on char entrainment in fluidised beds

The paper presents a 3-dimensional simulation of the effect of particle shape on char entrainment in a bubbling fluidised bed reactor. Three char particles of 350 μm side length but of different shapes (cube, sphere, and tetrahedron) are injected into the fluidised bed and the momentum transport from the fluidising gas and fluidised sand is modelled. Due to the fluidising conditions, reactor design and particle shape the char particles will either be entrained from the reactor or remain inside the bubbling bed. The sphericity of the particles is the factor that differentiates the particle motion inside the reactor and their efficient entrainment out of it. The simulation has been performed with a completely revised momentum transport model for bubble three-phase flow, taking into account the sphericity factors, and has been applied as an extension to the commercial finite volume code FLUENT 6.3. © 2010 Elsevier B.V.All rights reserved.

Three essays on the microstructure of exchange traded funds

Exchange traded funds (ETFs) have increased significantly in popularity since they were first introduced in 1993. However, there is still much that is unknown about ETFs in the extant literature. This dissertation attempts to fill gaps in the ETF literature by using three related essays. In these three essays, we compare ETFs to closed ended mutual funds (CEFs) by decomposing the bid-ask spread into its three components; we look at the intraday shape of ETFs and compare it to the intraday shape of equities as well as examine the co-integration factor between ETFs on the London Stock Exchange and the New York Stock Exchange; we also examine the differences between leveraged ETFs and unleveraged ETFs by analyzing the impact of liquidity and volatility. These three essays are presented in Chapters 1, 2, and 3, respectively. ^ Chapter one uses the Huang and Stoll (1997) model to decompose the bid-ask spread in CEFs and ETFs for two distinct periods—a normal and a volatile period. We show a higher adverse selection component for CEFs than for ETFs without regard to volatility. However, both ETFs and CEFs increased in magnitude of the adverse selection component in the period of high volatility. Chapter two uses a mix of the Werner and Kleidon (1993) and the Hupperets and Menkveld (2002) methods to get the intraday shape of ETFs and analyze co-integration between London and New York trading. We find two different shapes for New York and London ETFs. There also appears to be evidence of co-integration in the overlapping two-hour trading period but not over the entire trading day for the two locations. The third chapter discusses the new class of ETFs called leveraged ETFs. We examine the liquidity and depth differences between unleveraged and leveraged ETFs at the aggregate level and when the leveraged ETFs are classified by the leveraged multiples of -3, -2, -1, 2, and 3, both for a normal and a volatile period. We find distinct differences between leveraged and unleveraged ETFs at the aggregate level, with leveraged ETFs having larger spreads than unleveraged ETFs. Furthermore, while both leveraged and unleveraged ETFs have larger spreads in high volatility, for the leveraged ETFs the change in magnitude is significantly larger than for the unleveraged ETFs. Among the multiples, the -2 leveraged ETF is the most pronounced in its liquidity characteristics, more so in volatile times. ^

Sub-wavelength resonators as seismic Rayleigh waves shield

We explore the thesis that tall structures can be protected by means of seismic metamaterials. Seismic metamaterials can be built as some elements are created over soil layer with different shapes, dimensions, patterns and from different materials. Resonances in these elements are acting as locally resonant metamaterials for Rayleigh surface waves in the geophysics context. Analytically we proved that if we put infinite chain of SDOF resonator over the soil layer as an elastic, homogeneous and isotropic material, vertical component of Rayleigh wave, longitudinal resonance of oscillators will couple with each other, they would create a Rayleigh bandgap frequency, and wave will experience attenuation before it reaches the structure. As it is impossible to use infinite chain of resonators over soil layer, we considered finite number of resonators throughout our simulations. Analytical work is interpreted using finite element simulations that demonstrates the observed attenuation is due to bandgaps when oscillators are arranged at sub-wavelength scale with respect to the incident Rayleigh wave. For wavelength less than 5 meters, the resulting bandgaps are remarkably large and strongly attenuating when impedance of oscillators matches impedance of soil. Since longitudinal resonance of SDOF resonator are proportional to its length inversely, a formed array of resonators that attenuates Rayleigh waves at frequency ≤10 Hz could be designed starting from vertical pillars coupled to the ground. Optimum number of vertical pillars and their interval spacing called effective area of resonators are investigated. For 10 pillars with effective area of 1 meter and resonance frequency of 4.9 Hz, bandgap frequency causes attenuation and a sinusoidal impulsive force illustrate wave steering down phenomena. Simulation results proved analytical findings of this work.

Unnatural History: Ecological Temporality in Post-1945 American Literature

While environmental literary criticism has traditionally focused its attention on the textual representation of specific places, recent ecocritical scholarship has expanded this focus to consider the treatment of time in environmental literature and culture. As environmental scholars, activists, scientists, and artists have noted, one of the major difficulties in grasping the reality and implications of climate change is a limited temporal imagination. In other words, the ability to comprehend and integrate different shapes, scales, and speeds of history is a precondition for ecologically sustainable and socially equitable responses to climate change.

My project examines the role that literary works might play in helping to create such an expanded sense of history. As I show how American writers after 1945 have treated the representation of time and history in relation to environmental questions, I distinguish between two textual subfields of environmental temporality. The first, which I argue is characteristic of mainstream environmentalism, is disjunctive, with abrupt environmental changes separating the past and the present. This subfield contains many canonical works of postwar American environmental writing, including Aldo Leopold’s A Sand County Almanac, Edward Abbey’s Desert Solitaire, Annie Dillard’s Pilgrim at Tinker Creek, and Kim Stanley Robinson’s Science in the Capital trilogy. From treatises on the ancient ecological histories of particular sites to meditations on the speed of climate change, these works evince a preoccupation with environmental time that has not been acknowledged within the spatially oriented field of environmental criticism. However, by positing radical breaks between environmental pasts and environmental futures, they ultimately enervate the political charge of history and elide the human dimensions of environmental change, in terms both of environmental injustice and of possible social responses.

By contrast, the second subfield, which I argue is characteristic of environmental justice, is continuous, showing how historical patterns persist even across social and ecological transformations. I trace this version of environmental thought through a multicultural corpus of novels consisting of Ralph Ellison’s Invisible Man, Ishmael Reed’s Mumbo Jumbo, Helena María Viramontes’ Under the Feet of Jesus, Linda Hogan’s Solar Storms, and Octavia Butler’s Parable of the Sower and Parable of the Talents. Some of these novels do not document specific instances of environmental degradation or environmental injustice and, as a result, have not been critically interpreted as relevant for environmental analysis; others are more explicit in their discussion of environmental issues and are recognized as part of the canon of American environmental literature. However, I demonstrate that, across all of these texts, counterhegemonic understandings of history inform resistance to environmental degradation and exploitation. These texts show that environmental problems cannot be fully understood, nor environmental futures addressed, without recognizing the way that social histories of inequality and environmental histories of extraction continue to structure politics and ecology in the present.

Ultimately, then, the project offers three conclusions. First, it suggests that the second version of environmental temporality holds more value than the first for environmental cultural studies, in that it more compellingly and accurately represents the social implications of environmental issues. Second, it shows that “environmental literature” is most usefully understood not as the literature that explicitly treats environmental issues, but rather as the literature that helps to produce the sense of time that contemporary environmental crises require. Third, it shows how literary works can not only illuminate the relationship between American ideas about nature and social justice, but also operate as a specifically literary form of eco-political activism.

Estudo do consumo energético associado ao processo de cozedura na indústria cerâmica

O presente trabalho realizou-se no âmbito do Projeto Galp 20-2020 implementado na empresa Sanindusa, em parceira com a Universidade de Aveiro. Como principal objetivo pretendia-se estudar o consumo de energia durante o processo de cozedura das peças cerâmicas com o intuito de avaliar a viabilidade da substituição do refratário existente na empresa. Uma vez que esta medida implicaria um tempo de retorno do investimento demasiado elevado, optou-se por estudar o consumo de energia associado a uma placa horizontal, de massa unitária, de qualquer tipo de material refratário. Para tal, foi desenvolvido um Modelo Teórico capaz de calcular o calor absorvido por uma placa de refratário ao longo de todo o percurso dentro do Forno Túnel 2, existente na empresa e utilizado no processo de produção das peças cerâmicas. Através deste estudo foi possível concluir que o Modelo Teórico é bastante útil na medida em que permite a criação de vários cenários, através da alteração de diversas variáveis, permitindo conhecer qual o impacto de cada uma no consumo de energia neste equipamento. Como trabalho futuro propõe-se o desenvolvimento do Modelo Teórico apresentado para o estudo da transferência de calor bidimensional. Esta melhoria permitiria analisar o consumo de energia associado a diferentes formas de material refratário utilizado no processo de cozedura de peças cerâmicas (o que não é possível quando se aplica o conceito de transferência de calor unidimensional).

Tinta Barroca: identidade e comunicação para uma marca de promoção de eventos hoteleiros

A ilustração aplicada ao branding resulta de um modo reflexivo por parte do autor. Esse modo é, por si só, o papel do ilustrador como designer gráfico. A identidade de uma marca nasce da sua história, contexto e sensações, as quais o autor adquire e transmite, segundo as suas vivências, de modo a responder às necessidades das pessoas que o rodeiam. O desenvolvimento de uma marca é um longo processo de análise e reflexão, contínuo e exigente. Aplicando a ilustração a este meio, como objeto visual principal, a língua deixa de ser um entrave e a identidade passa a ser comunicada aos olhos e memória de qualquer um, de forma imediata e eficaz. Conceptualmente, a Tinta Barroca absorve estes princípios, transformando-se numa marca de eventos culturais, embora bastante focada em eventos que podem abranger jantares bem portugueses ou provas de vinho. O projeto foi desenvolvido à base do experimentalismo. Todas as ilustrações da marca foram, numa primeira fase, produzidas manualmente e posteriormente tratadas digitalmente, testando diferentes formas, texturas e materiais. A excessividade ilustrativa é o ponto de partida para comunicar as ideologias da Tinta Barroca, baseando-se no barroquismo, erotismo e nos prazeres da vida. A identidade gráfica da marca misturase com uma decoração já pré-definida: uma mesa bem preenchida e recheada de flores, frutos, vinho e comidas divinais, que se aproximam, pelo excesso, dos princípios do barroco.

Functional heterogeneity of medial posterior parietal cortex of macaque monkey

The posterior parietal cortex (PPC) of primates represents a remarkable platform that has evolved over time to solve some of the computational challenges that we face in the everyday life, such as sensorimotor integration, spatial attention, and motor planning. With the aim of further investigating the multifaceted functional characteristics of medial PPC, we conducted three studies to explore the visuomotor, somatic, visual, and attention-related properties of two PPC areas: V6A, a visuomotor area part of the dorsomedial visual stream, and PE, an area strongly dominated by somatomotor input, residing mainly on the exposed surface of the superior parietal lobule. In the first study, we tested the impact of visual feedback on V6A grasp-related activity during arm movements towards objects of different shapes. Our results demonstrate that V6A is modulated by both grip type and visual information during grasping preparation and execution, with a predominance of cells influenced by grip type. In the second study, we explored the influence of depth and direction information on reach-related activity of neurons in the so far largely neglected medial part of area PE. We observed a remarkable trend in medial PPC, going from the joint coding of depth and direction signals caudally, in area V6A, to a largely segregated processing of the two signals rostrally, in area PE. In the third study, we used a combined fMRI-electrophysiology experiment to investigate the neuronal mechanisms underlying covert shift of attention processes in area V6A. Our preliminary results reveal that half of the cells showed shift-selective activity when the monkey covertly shifted its attention towards the receptive field. All together these findings highlight the role of the medial PPC in integrating information coming from different sources (vision, somatosensory and motor) and emphasize the involvement of action-related regions of the dorsomedial visual stream in higher level cognitive functions.

GÉOARCHÉOLOGIE DU VILLAGE: Variabilité des modes d’occupation de la fin du Néolithique à l’âge du Bronze en Italie et en France méridionale. Implications culturelles

Entre la fin du Néolithique et l’âge du Bronze, la présence d’habitats groupés de type village est un phénomène diffus, tant en Italie qu’en France méridionale. Néanmoins, la prise en compte de la variabilité des formes de la stratification des sites interroge. En quoi l’enregistrement sédimentaire des sols d’habitat permet-il d’appréhender la question de l’organisation villageoise et de sa variabilité entre la fin du Néolithique et l’âge du Bronze ? Quelle image cet enregistrement sédimentaire donne-t-il de l’organisation sociale et économique du village ? Afin d’aborder ces questions, nous avons choisi de mener une étude géoarchéologique sur des sites de formes différentes, issus de contextes chrono-culturels et environnementaux variés. La démarche, fondée sur l’emploi de la micromorphologie des sols en tant qu’outil analytique, vise à caractériser l’organisation spatio-temporelle des sols d’occupation à l’échelle du site, selon une approche spatiale des processus de formation de la stratification archéologique. L’élaboration d’un modèle, qui repose sur une classification des micro-faciès sédimentaires selon le système d’activité, et son application à des sites-laboratoires permettent de qualifier les techniques de construction en terre, l’usage du sol et les dynamiques d’occupation propres à chaque site, dans le but de déterminer les comportements socio-économiques et les spécificités du mode de vie villageois enregistrées par les sols. Cette approche permet d’évaluer les constantes et les variables qui qualifient les différents types d’occupation. Le sol, conçu comme matérialité de l’espace villageois, devient ainsi un témoignage direct de la variabilité culturelle et des différentes formes d’organisation des communautés de la fin du Néolithique et de l’âge du Bronze.

Innovative photoresponsive materials & supramolecular structures

This thesis focuses on two main topics: photoresponsive azobenzene-based polymers and supramolecular systems generated by the self-assembly of lipophilic guanosines. In the first chapters describe innovative photoresponsive devices and materials capable of performing multiple roles in the field of soft robotics and energy conversion. Chapter 2 describes a device obtained by coupling a photoresponsive liquid-crystalline network and a piezoelectric polymer to convert visible light into electricity. Chapter 3 deals with a material that can assume different shapes when triggered by three different stimuli in different environments. Chapter 4 reports a highly performing artificial muscle that contracts when irradiated. The last two chapters report on supramolecular structures generated from functionalized guanosines dissolved in organic solvents. Chapter 6 illustrates the self-assembly into G-quadruplexes of 8- and 5’-functionalized guanosines in the absence of templating ions. Chapter 7 describes the supramolecular structure generated by the assembly of a lipophilic guanosine in the presence of silver cations. Chapter 6 is reproduced from an already published paper, while the other chapters are going to be submitted to different journals in a couple of months.

A numerical investigation on the visco-plastic response of structures to different pulse loading shapes

The time varying intensity character of a load applied to a structure poses many difficulties in analysis. A remedy to this situation is to substitute a complex pulse shape by a rectangular equivalent one. It has been shown by others that this procedure works well for perfectly plastic elementary structures. This paper applies the concept of equivalent pulse to more complex structures. Special attention is given to the material behavior, which is allowed to be strain rate and strain hardening sensitive. Thanks to the explicit finite element solution, it is shown in this article that blast loads applied to complex structures made of real materials can be substituted by equivalent rectangular loads with both responses being practically the same. (c) 2007 Elsevier Ltd. All rights reserved.

Exogenous selection shapes germination behaviour and seedling traits of populations at different altitudes in a Senecio hybrid zone.

BACKGROUND AND AIMS: The Senecio hybrid zone on Mt Etna, Sicily, is characterized by steep altitudinal clines in quantitative traits and genetic variation. Such clines are thought to be maintained by a combination of 'endogenous' selection arising from genetic incompatibilities and environment-dependent 'exogenous' selection leading to local adaptation. Here, the hypothesis was tested that local adaptation to the altitudinal temperature gradient contributes to maintaining divergence between the parental species, S. chrysanthemifolius and S. aethnensis. METHODS: Intra- and inter-population crosses were performed between five populations from across the hybrid zone and the germination and early seedling growth of the progeny were assessed. KEY RESULTS: Seedlings from higher-altitude populations germinated better under low temperatures (9-13 °C) than those from lower altitude populations. Seedlings from higher-altitude populations had lower survival rates under warm conditions (25/15 °C) than those from lower altitude populations, but also attained greater biomass. There was no altitudinal variation in growth or survival under cold conditions (15/5 °C). Population-level plasticity increased with altitude. Germination, growth and survival of natural hybrids and experimentally generated F(1)s generally exceeded the worse-performing parent. CONCLUSIONS: Limited evidence was found for endogenous selection against hybrids but relatively clear evidence was found for divergence in seed and seedling traits, which is probably adaptive. The combination of low-temperature germination and faster growth in warm conditions might enable high-altitude S. aethnensis to maximize its growth during a shorter growing season, while the slower growth of S. chrysanthemifolius may be an adaptation to drought stress at low altitudes. This study indicates that temperature gradients are likely to be an important environmental factor generating and maintaining adaptive divergence across the Senecio hybrid zone on Mt Etna.

Design and Analysis of Microstrip Lines with EBG-Backed Ground Planes of Different Geometrical Shapes

Propagation of electromagnetic waves through a microstrip line with 2D electromagnetic baud gap (EBG) structures of different geometrical shapes in the ground plane is investigated in this paper. Using transmission-line theory, the design equations for EBG structures are calculated. The measured, numerical. and simulated results are in gone) agreement

Is affective learning really resistant to extinction? Stimulus ratings and affective priming give different answers

Affective learning, the learning of likes and dislikes, is proposed to differ from signal learning, the learning of relationships between events. However, affective learning research varies in the methodology used, and in addition, researchers concerned primarily with affective learning tend to use different paradigms from those concerned with signal learning. The current research used an affective priming task in addition to verbal ratings to assess changes in the valence of neutral geometric shapes in an aversive differential conditioning procedure. After acquisition, affective learning was present as indexed by ratings and affective priming, whereas after extinction, affective learning remained significant only in the ratings. This study suggests that different measures of affective learning may be differentially sensitive to valence, which has implications for studies that employ verbal ratings as the sole measure of affective learning. Moreover, there is no evidence from the current study that affective learning differs from signal learning.

Influence of shapes of selected vegetable materials on drying kinetics during fluidized bed drying

Three different particular geometrical shapes of parallelepiped, cylinder and sphere were taken from cut green beans (length:diameter = 1:1, 2:1 and 3:1) and potatoes (aspect ratio = 1:1, 2:1 and 3:1) and peas, respectively. Their drying behaviour in a fluidised bed was studied at three different drying temperatures of 30, 40 and 50 degreesC (RH = 15%). Drying curves were constructed using non-dimensional moisture ratio (MR) and time and their behaviour was modelled using exponential (MR = exp(-kt)) and Page (MR = exp(-kt(n))) models. The effective diffusion coefficient of moisture transfer was determined by Fickian method using uni- and three-dimensional moisture movements. The diffusion coefficient was least affected by the size when the moisture movement was considered three-dimensional, whereas the drying temperature had a significative effect on diffusivity as expected. The drying constant and diffusivity coefficients were on the descending order for potato, beans and peas. The Arrhenius activation energy for the peas was also highest, indicating a strong barrier to moisture movement in peas as compared to beans and skinless cut potato pieces. (C) 2003 Elsevier Science Ltd. All rights reserved.