321 research outputs found

    Covid-19 pandemic and food security: A comparative study between the United States (California) and Portugal

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    The Covid-19 Pandemic has been a seismic event. Its effect on food systems and supply chains and how governments reacted to these crises will have a long-lasting impact on food security policy. Food security is currently at the forefront due to stress on natural resources and supply chains presented by climate change, famines, population fluctuations, and more recently, pandemics and wars. Agricultural and food system policies are directly linked to economic systems and trade policies enacted by governments. This thesis will focus on a comparative analysis of food security policies adopted from an economic perspective between the United States and European Union, with a focus on Portugal and California, in response to the Covid-19 Pandemic and where their policies may be headed moving forward. Policies will be broken down into three time periods: the Post-World War II, ColdWar era (1945-1980s); the post-ColdWar, unipolar era (1980s-2015); and the multipolar, pandemic era (2015-present). Then, these policies will be classified as either normalist or exceptionalist, with the intended target-level of society being either macro, meso, or micro. Data will be used to explain the rationale behind the actions taken. This data will consist of statements from politicians, public polls, unemployment, food insecurity, and poverty statistics, ranging from governmental and institutional sources, university studies, and public data. Since the invasion of Ukraine started after beginning this thesis, it will be taken into consideration because it provides a direct example of government response to a crisis in the post-Covid-19 world.A pandemia de Covid-19 foi um evento sísmico. O seu efeito sobre os sistemas alimentares e cadeias de abastecimento e como os governos reagiram a estas crises terão um impacto duradouro na política de segurança alimentar. A segurança alimentar está atualmente na vanguarda devido à pressão sobre os recursos naturais e cadeias de abastecimento fomentadas pelas alterações climáticas, fomes, variações populacionais e, recentemente, pandemias e guerras. As políticas agrícolas e o sistema alimentar estão diretamente conectados aos sistemas e às políticas comerciais promulgadas pelos governos. Esta dissertação concentrar-se-á numa análise comparativa sobre políticas de segurança alimentar adotadas a partir de uma perspetiva entre os Estados Unidos e a União Europeia, particularmente em Portugal e na Califórnia, na resposta à Pandemia Covid-19 e ao futuro destas políticas. Estas políticas serão divididas em três períodos: pós-Segunda Guerra Mundial e era da Guerra Fria (1945-1980); pós-Guerra Fria e era unipolar (1980-2015); era multipolar e pandemia (2015-presente). Estas políticas são classificadas como normais ou excecionais, tendo como objetivo alcançar pelo menos um nível da sociedade, seja micro, meso ou macro. Os dados usados terão o objetivo de explicar a lógica destas políticas tomadas. Esses dados consistem em declarações de líderes políticos, pesquisas de opinião, estatísticas sobre desemprego, insegurança alimentar e pobreza, usando diversas fontes governamentais e institucionais, estudos universitários e dados públicos. Como a invasão da Ucrânia começou após o início desta dissertação, esta será tida em consideração porque representa um exemplo direto da resposta do governo a uma crise no mundo pós-Covid-19

    Occurrence cubes : a new paradigm for aggregating species occurrence data

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    In this paper we describe a method of aggregating species occurrence data into what we coined “occurrence cubes”. The aggregated data can be perceived as a cube with three dimensions - taxonomic, temporal and geographic - and takes into account the spatial uncertainty of each occurrence. The aggregation level of each of the three dimensions can be adapted to the scope. Built on Open Science principles, the method is easily automated and reproducible, and can be used for species trend indicators, maps and distribution models. We are using the method to aggregate species occurrence data for Europe per taxon, year and 1km2 European reference grid, to feed indicators and risk mapping/modelling for the Tracking Invasive Alien Species (TrIAS) project

    Spatiotemporal Statistical Downscaling for the Fusion of In-lake and Remote Sensing Data

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    This paper addresses the problem of fusing data from in-lake monitoring programmes with remote sensing data, through statistical downscaling. A Bayesian hierarchical model is developed, in order to fuse the in-lake and remote sensing data using spatially-varying coefficients. The model is applied to an example dataset of log(chlorophyll-a) data for Lake Erie, one of the Great Lakes of North America

    Mechanical Design and Fabrication of Rotating Test Stand for Supersonic Wind Tunnel

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    This research project focuses on the design and manufacturing of a rotating test stand for the Cal Poly Supersonic Wind Tunnel (SSWT). In order to establish essential design parameters, the project employs compressible flow isentropic relationships to calculate the Mach number within the test section and determine static pressures. This comprehensive effort integrates preliminary design and manufacturing processes, utilizing CAD designs and a range of machinery for component fabrication, while also highlighting initial testing of the rotating test stand\u27s ability to withstand predicted aerodynamic loads. As part of the research\u27s future work, rigorous structural stability testing and the implementation of flow visualization techniques, such as shadowgraph imaging, are planned to validate the design and optimize aerodynamic performance. The project aims to not only advance our understanding of aerodynamics but also offer valuable educational opportunities for undergraduate students

    Diffractive Vector Meson Photoproduction from Dual String Theory

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    We study diffractive vector meson photoproduction using string theory via AdS/CFT. The large ss behavior of the cross sections for the scattering of the vector meson VV on a proton is dominated by the soft Pomeron, σVs2ϵ2αP/B\sigma_V\sim s^{2\epsilon-2\alpha'_P/B}, where from the string theory model of \cite{nastase2}, ϵ\epsilon is approximately 1/7 below 10 GeV, and 1/11 for higher, but still sub-Froissart, energies. This is due to the production of black holes in the dual gravity. In ϕ\phi-photoproduction the mesonic Regge poles do not contribute, so that we deal with a pure Pomeron contribution. This allows for an experimental test. At the gauge theory "Planck scale" of about 1-2 GeV, the ratios of the soft Pomeron contributions to the photoproduction cross-sections of different vector mesons involve not only the obvious quark model factors, but also the Boltzmann factors e4MV/T0e^{-4 M_V/T_0}, with T0T_0 the temperature of the dual black hole. The presence of these factors is confirmed in the experimental data for ρ,ω,ϕ,J/ψ,\rho, \omega, \phi, J/\psi, and ψ(2S)\psi(2S) photoproduction and is compatible with the meager Υ\Upsilon photoproduction data. Throughout, we use vector meson dominance, and from the data we obtain T0T_0 of about 1.3GeV1.3 GeV, i.e. the gauge theory "Planck scale," as expected. The ratio of the experimental soft Pomeron onset scale E^R9\hat{E}_R\sim 9 GeV and of the gauge theory Planck scale, T01.3T_0 \sim 1.3 GeV conforms to the theoretical prediction of Nc2/Nc1/4N_c^2/N_c^{1/4}.Comment: 17 pages, 1 figure, late

    The Rise Times of High and Low Redshift Type Ia Supernovae are Consistent

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    We present a self-consistent comparison of the rise times for low- and high-redshift Type Ia supernovae. Following previous studies, the early light curve is modeled using a t-squared law, which is then mated with a modified Leibundgut template light curve. The best-fit t-squared law is determined for ensemble samples of low- and high-redshift supernovae by fitting simultaneously for all light curve parameters for all supernovae in each sample. Our method fully accounts for the non-negligible covariance amongst the light curve fitting parameters, which previous analyses have neglected. Contrary to Riess et al. (1999), we find fair to good agreement between the rise times of the low- and high-redshift Type Ia supernovae. The uncertainty in the rise time of the high-redshift Type Ia supernovae is presently quite large (roughly +/- 1.2 days statistical), making any search for evidence of evolution based on a comparison of rise times premature. Furthermore, systematic effects on rise time determinations from the high-redshift observations, due to the form of the late-time light curve and the manner in which the light curves of these supernovae were sampled, can bias the high-redshift rise time determinations by up to +3.6/-1.9 days under extreme situations. The peak brightnesses - used for cosmology - do not suffer any significant bias, nor any significant increase in uncertainty.Comment: 18 pages, 4 figures, Accepted for publication in the Astronomical Journal. Also available at http://www.lbl.gov/~nugent/papers.html Typos were corrected and a few sentences were added for improved clarit

    Increasing understanding of alien species through citizen science (Alien-CSI)

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    There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing scientific understanding of AS dynamics while informing decision-making specifically implementation of technical requirements of relevant legislation such as the EU Regulation 1143/2014 on IAS. It will also support the EU biodiversity goals and embedding science within society. The Action will explore and document approaches to establishing a European-wide CS AS network. It will embrace relevant innovations for data gathering and reporting to support the implementation of monitoring and surveillance measures, while ensuring benefits for society and citizens, through an AS CS European network. The Action will, therefore, increase levels of participation and quality of engagement with current CS initiatives, ensuring and evaluating educational value, and improve the value outcomes for potential users including citizens, scientists, alien species managers, policy-makers, local authorities, industry and other stakeholders

    Developments in Earth observation for the assessment and monitoring of inland, transitional, coastal and shelf-sea waters

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    The Earth's surface waters are a fundamental resource and encompass a broad range of ecosystems that are core to global biogeochemical cycling and food and energy production. Despite this, the Earth's surface waters are impacted by multiple natural and anthropogenic pressures and drivers of environmental change. The complex interaction between physical, chemical and biological processes in surface waters poses significant challenges for in situ monitoring and assessment and often limits our ability to adequately capture the dynamics of aquatic systems and our understanding of their status, functioning and response to pressures. Here we explore the opportunities that Earth observation (EO) has to offer to basin-scale monitoring of water quality over the surface water continuum comprising inland, transition and coastal water bodies, with a particular focus on the Danube and Black Sea region. This review summarises the technological advances in EO and the opportunities that the next generation satellites offer for water quality monitoring. We provide an overview of algorithms for the retrieval of water quality parameters and demonstrate how such models have been used for the assessment and monitoring of inland, transitional, coastal and shelf-sea systems. Further, we argue that very few studies have investigated the connectivity between these systems especially in large river-sea systems such as the Danube-Black Sea. Subsequently, we describe current capability in operational processing of archive and near real-time satellite data. We conclude that while the operational use of satellites for the assessment and monitoring of surface waters is still developing for inland and coastal waters and more work is required on the development and validation of remote sensing algorithms for these optically complex waters, the potential that these data streams offer for developing an improved, potentially paradigm-shifting understanding of physical and biogeochemical processes across large scale river-sea continuum including the Danube-Black Sea is considerable
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