1,276 research outputs found

    Using wavelets for time series forecasting: Does it pay off?

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    By means of wavelet transform a time series can be decomposed into a time dependent sum of frequency components. As a result we are able to capture seasonalities with time-varying period and intensity, which nourishes the belief that incorporating the wavelet transform in existing forecasting methods can improve their quality. The article aims to verify this by comparing the power of classical and wavelet based techniques on the basis of four time series, each of them having individual characteristics. We find that wavelets do improve the forecasting quality. Depending on the data's characteristics and on the forecasting horizon we either favour a denoising step plus an ARIMA forecast or an multiscale wavelet decomposition plus an ARIMA forecast for each of the frequency components. --Forecasting,Wavelets,ARIMA,Denoising,Multiscale Analysis

    Forced Labor Found Within The Supply Chains of The Coffee Industry

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    I have focused my research on the morality within supply chains that source major coffee companies around the world. As consumers, many of us have no idea where the products that we use everyday truly come from. The purchases we make have the power to feed into the issue of forced labor. The coffee we buy often does. My thesis takes a look into the extensive issue of human trafficking and unjust labor practices on the plantations that provide us with the coffee we sip on each morning. This paper serves to enlighten producers and consumers on this phenomenon, to expose the companies, plantations and systems behind it, have the voices of those trapped into modern slavery be heard, and recruit my fellow business leaders to help fight the good fight against forced labor

    Forced Labor Found Within The Supply Chains of The Coffee Industry

    Get PDF
    I have focused my research on the morality within supply chains that source major coffee companies around the world. As consumers, many of us have no idea where the products that we use everyday truly come from. The purchases we make have the power to feed into the issue of forced labor. The coffee we buy often does. My thesis takes a look into the extensive issue of human trafficking and unjust labor practices on the plantations that provide us with the coffee we sip on each morning. This paper serves to enlighten producers and consumers on this phenomenon, to expose the companies, plantations and systems behind it, have the voices of those trapped into modern slavery be heard, and recruit my fellow business leaders to help fight the good fight against forced labor

    Theoretical perspective on rebound effects from a social science point of view: Working paper to prepare empirical psychological and sociological studies in the REBOUND project

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    The replacement of appliances and other energy using products by more efficient ones is generally regarded as an effective strategy to reduce energy demand. However, the savings realized by this strategy may be lower than those theoretically expected or calculated from a technological point of view due to changes of behaviour following the acquisition. This phenomenon is known as the rebound effect. While scientists generally agree on the existence of rebound effects, size, relevance and explanations of such effects are controversially discussed. This paper discusses concepts to explain rebound effects from a psychological as well as sociological point of view. In particular, an approach which combines variables from psychological action theories with the sociological life-style concept is suggested as a framework for studying determinants of rebound effects. --

    Cross-sectional study of the dispensation of synthetic anorectic drugs in community pharmacies in the city of Cruz Alta - State of Rio Grande do Sul

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    Obesity is defined as the excess adipose tissue in the body. Drugs responsible for inhibiting the appetite are called anorectics or appetite suppressants. Sibutramine, fenproporex and amfepramone belongs to this class, and are capable of causing physical or psychological dependence. The aim of this study was to evaluate the frequency of prescriptions for appetite suppressants in community pharmacies at Cruz Alta, State of Rio Grande do Sul, Brazil. The sales of fenproporex, amfepramone and sibutramine in the months of September, October and November 2010 and April, May and June 2011 were compared. It was observed that the most commonly dispensed anorectic in the three community pharmacies analyzed was sibutramine. In the months of September, October and November 2010, consumption was higher, with sibutramine achieving 40.3% of overall sales, amfepramone 21% and, finally, fenproporex, 7.9%. The consumption of appetite suppressants was more prevalent in females, who represented 82% of total. The results suggested the existence of high consumption of anorectics, possibly related to the current concern with aesthetic standards, which emphasizes the importance of strict control over the marketing of these substances.Obesidade define-se como excesso de tecido adiposo no organismo. Os fármacos responsáveis por inibir o apetite são denominados anorexígenos ou supressores de apetite. Sibutramina, femproporex e anfepramona, pertencentes a essa classe, são capazes de provocar dependência física ou psíquica. O objetivo deste estudo foi avaliar a prevalência da prescrição de anorexígenos em farmácias comerciais de Cruz Alta - RS. Foi comparada a venda dos fármacos femproporex, anfepramona e sibutramina, nos meses de setembro, outubro e novembro de 2010 e abril, maio e junho de 2011. Observou-se que o anorexígeno mais prescrito nas três farmácias analisadas foi a sibutramina. Nos meses de setembro, outubro e novembro de 2010, o consumo foi maior, quando a sibutramina alcançou um percentual de 40,3%, a anfepramona 21% e, por fim, o femproporex, 7,9%. O consumo de inibidores de apetite foi mais prevalente no sexo feminino, o qual representou 82% do total. Os resultados sugeriram a existência de elevado consumo de anorexígenos, possivelmente relacionada à preocupação com padrões estéticos atuais, o que ressalta a importância de um controle rigoroso sobre a comercialização destas substâncias

    Physical chemistry evaluation of stability, spreadability, in vitro antioxidant, and photo-protective capacities of topical formulations containing Calendula officinalis L. leaf extract

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    A calêndula é amplamente utilizada em formulações cosméticas, apresentando compostos fenólicos em sua constituição química. Desta forma, o objetivo desta pesquisa foi desenvolver e avaliar a estabilidade de formulações tópicas contendo 5% de extrato hidroetanólico das folhas de calêndula, bem como a espalhabilidade, capacidade antioxidante e fotoprotetora in vitro nas mesmas. Para a avaliação da estabilidade, foram usados parâmetros como a verificação das características organolépticas, pH e viscosidade. A capacidade antioxidante foi verificada pelo método do DPPH (2,2-difenil,1- picril-hidrazila) e a capacidade fotoprotetora pela medida espectrofotométrica do FPS. Para as formulações testadas, observou-se que apresentaram uma boa estabilidade. As formulações de creme e gel com extrato de calêndula não apresentaram variações significativas nos valores de pH e o creme apresentou as menores variações de viscosidade em relação ao gel. A espalhabilidade das formulações de gel foi superior à do creme. As formulações também apresentaram uma boa capacidade antioxidante e um FPS em torno de 1.75. De acordo com os resultados, a formulação pode ser utilizada com ação antioxidante, porém com o FPS obtido, a calêndula não pode ser considerada um filtro solar isolado, mas poderá ser testada em estudos futuros para verificar a potencialização de filtros solares sintéticos.Calendula is used widely in cosmetic formulations that present phenolic compounds in their chemical constitution. The objective of our research was to develop and evaluate the stability of topical formulations containing 5% hydro-ethanolic extract of calendula leaves, including spreadability, and in vitro photo-protective, and antioxidant capacity. To evaluate the stability, we used organoleptic characteristics, pH, and viscosity parameters. Antioxidant capacity was measured by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, and the photo-protective capacity by SPF spectrophotometric measure. All formulations were stable. The calendula extract formulations in gel and cream showed no significant variations in pH, and the cream formulations presented lower viscosity variations than gel formulations. The spreadability of the gel formulations was superior to those in cream. The formulations also presented good antioxidant capacities and an FPS of around 1.75. In accordance with the results, the formulations can be used as antioxidants, but considering the low SPF obtained, calendula cannot be considered as a stand-alone sunscreen, yet may well be tested in future studies towards verifying enhancement of synthetic sunscreens

    Ab initio Self-consistent GW Calculations in Non-Equilibrium Devices: Auger Recombination and Electron-Electron Scattering

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    We present first-principles quantum transport simulations of single-walled carbon nanotubes based on the NEGF method and including carrier-carrier interactions within the self-consistent GW approximation. Motivated by the characteristic enhancement of interaction between charge carriers in one-dimensional systems, we show that the developed framework can predict Auger recombination, hot carrier relaxation, and impact ionization in this type of nanostructures. Using the computed scattering rates, we infer the inverse electron-hole pair lifetimes for different Auger processes in several device configurations
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