5,799 research outputs found

    A macroeconomic framework for quantifying growth and poverty reduction strategies in Niger

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    The authors apply the dynamic macroeconomic framework developed by Agénor, Bayraktar, and El Aynaoui (2004) to Niger. As in the original model, linkages between foreign aid, public investment (disaggregated into education, infrastructure, and health), and growth are explicitly captured. Although the nominal exchange rate is fixed, the relative price of domestic goods is endogenous, thereby allowing for potential Dutch disease effects associated with increases in aid. The authors assess the impact of policy shocks on poverty by using partial growth elasticities. They perform various policy experiments, including an increase in the level of foreign aid, a reallocation of public investment toward infrastructure, and neutral and non-neutral cuts in tariffs. The simulations show the dynamic tradeoffs that these policies entail with respect to growth and poverty reduction in Niger.Payment Systems&Infrastructure,Economic Theory&Research,Public Sector Economics&Finance,Environmental Economics&Policies,Banks&Banking Reform,Environmental Economics&Policies,Economic Theory&Research,Public Sector Economics&Finance,Banks&Banking Reform,Municipal Financial Management

    The composition of public expenditure and growth : a small-scale intertemporal model for low-income countries

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    This paper presents a small-scale intertemporal model of endogenous growth that accounts for the composition of public expenditure and externalities associated with public capital. Government spending is disaggregated into various components, including maintenance, security, and investment in education, health, and core infrastructure. After studying its long-run properties, the model is calibrated for Haiti, using country-specific information as well as parameter estimates from the literature. A variety of policy experiments are then reported, including a reallocation of spending aimed at creating fiscal space to promote public investment; an improvement in fiscal management that leads to a reduction in tax collection costs; higher spending on security; and a composite fiscal package.,Debt Markets,Economic Theory&Research,Public Sector Economics&Finance,Public Sector Expenditure Analysis&Management

    Scarless laparoscopic repair of epigastric hernia in children

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    Background Despite the small size of the incision, the scar left by open repair of epigastric hernia in children is unaesthetic. Few laparoscopic approaches to epigastric hernia repair have been previously proposed, but none has gain wide acceptance from pediatric surgeons. In this study, we present our experience with a scarless laparo- scopic approach using a percutaneous suturing technique for epigastric hernia repair in children. Methods Ten consecutive patients presenting with epi- gastric hernia 15 mm or further from the umbilicus were submitted to laparoscopic hernia repair. A 5-mm 308-angle laparoscope is introduced through a umbilical trocar and a 3-mm laparoscopic dissector is introduced through a stab incision in the right flank. After opening and dissecting the parietal peritoneum, the fascial defect is identified and closed using 2–0 polyglactin thread through a percutaneous suturing technique. Intraoperative and postoperative clinical data were collected. Results All patients were successfully submitted to la- paroscopic epigastric hernia repair. Median age at surgery was 79 months old and the median distance from the um- bilicus to the epigastric defect was 4 cm. Operative time ranged from 35 to 75 min. Every hernia was successfully closed without any incidents. Follow-up period ranges from 2 to 12 months. No postoperative complications or recurrence was registered. No scar was visible in these patients. Conclusion This scarless laparoscopic technique for epi- gastric hernia repair is safe and reliable. We believe this technique might become gold standard of care in the near future

    PolĂ­ticas da desilusĂŁo: ViolĂȘncia e idealismo em “Civil War” de Liam O’Flaherty e “Guests of the Nation” de Frank O’Connor

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    Vivendo os seus anos de formação no perĂ­odo imediatamente anterior Ă  revolução irlandesa, Liam O’Flaherty e Frank O’Connor foram profundamente influenciados pela propaganda nacionalista. Inspirados por ideais republicanos, ambos os escritores assumiram um papel ativo, apesar de modesto, tanto na Guerra da IndependĂȘncia quanto na subsequente Guerra Civil. A literatura que produziram quando os conflitos cessaram, no entanto, apresenta uma perspectiva crĂ­tica e contrastante com os ideais que os tinham levado a apoiar a revolução. Analisando os contos “Civil War” (1924), de Liam O’Flaherty, e “Guests of the Nation” (1932), de Frank O’Connor, este artigo explora porquĂȘ e como ambos os autores recorreram a abordagens brutais e niilistas para retratar o perĂ­odo revolucionĂĄrio irlandĂȘs em vez de aderirem a perspectivas mais romĂąnticas e idealistas.Having their formative years in the period right before the Irish revolution, Liam O’Flaherty and Frank O’Connor were deeply influenced by nationalistic propaganda. Inspired by Republican ideals, both writers-to-be took an active, though modest, role in the War of Independence and in the ensuing Civil War. The literature they produced when the conflicts had ceased, however, displays a very critical and contrasting perspective to the one that had driven them to support the revolution. Analysing the short stories “Civil War” (1924), by Liam O’Flaherty, and “Guests of the Nation” (1932), by Frank O’Connor, this essay explores why and how both authors resorted to stark, gruesome, and nihilistic approaches to the Irish revolutionary period instead of adhering to more romantic and idealistic perspectives

    Light Signs, the Work of TeĂłfilo Rego for Neolux

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    The subject of our paper is the work carried out by the Portuguese photographer TeĂłfilo Rego (1913/1993), between the 1950s and the 1960s, for the manufacturing company of neon signs Neolux. Among the universes of the professional commission and the themes that, on his own initiative, explores in his personal work, the text addresses the images that may be considered as catalogue photography, reportage and architectural photography, and that remember us a time when, all over the world, the neon advertising was part of the urban landscape – from New York to Paris, Madrid, Lisbon and, in this case, Oporto. The article analyses the history, the type and the goals of the different advertising and light signage, the effect produced by their presence in city, and discusses the many images suggested and reminded by these photographs.This text was co-funded with FEDER funds by the Operational Competitiveness Programme – COMPETE and national funds by FCT – Fundação para a CiĂȘncia e Tecnologia within the project Photography, Modern Architecture and the “School of Oporto”: Interpretations Around TeĂłfilo Rego Archive (PTDC/ ATP-AQI/4805/2012 - FCOMP-01-0124-FEDER-028054

    Linking public investment programs and SPAHD macro models : methodology and application to aid requirements

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    The authors propose a"bottom up"approach to link public investment programs with a class of macro models recently developed to quantify Strategy Papers for Human Development (SPAHD) in low-income countries. The methodology involves establishing constant-price projections of investment outlays (disaggregated into infrastructure, education, and health), spending on maintenance and other goods and services, salaries, and user charges. These estimates are incorporated in a SPAHD macro framework to calculate, under alternative scenarios, domestic financing, foreign borrowing, and aid requirements. The authors also evaluate the impact on growth and indicators associated with the Millennium Development Goals. They use illustrative applications, based on a SPAHD model for Niger, to highlight the link between tax reform and aid requirements.Public Sector Economics&Finance,Economic Theory&Research,Public Sector Expenditure Analysis&Management,Investment and Investment Climate,Population Policies

    Collision Dynamics of a Single Droplet onto a Heated Dry Surface: Jet Fuel and HVO Mixtures

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    The concern with the environment led the human being to develop new alternative fuels to reduce pollution and mitigate the emission of greenhouse gases. The air transport sector and the burning of fossil fuels are responsible for a huge portion of the pollution. Therefore, introducing new sustainable ways to provide energy, such as biofuel, is of major importance. However, in order to make these new energy sources more efficient and safer, it is necessary to carry out studies related to the injection of fuel into the combustion chambers, and the impact of droplets. This study focuses on an experimental investigation of a single droplet impact onto a heated solid surface. The main purpose of this work is to analyse the influence of wall temperature on the impact morphology of a single droplet and observe the possible outcomes. To do so, in these experimental tests, Jet Fuel and HVO (Hydroprocessed Vegetable Oil) mixtures were used. The fluids tested were: water (as a control group), 100% Jet A-1, 75% Jet A-1 and 25% NExBTL, 50% Jet A-1 and 50% NExBTL, and 100% NExBTL. The present work studies the impact outcomes depending on the working fluids and the wall temperature. The impact energy was kept constant. Therefore, the Weber number in this experiment was set to W e = 320 by varying the droplet diameter or the impact velocity. Furthermore, different wall temperatures were chosen, that vary from Tw = 25ÂșC to Tw = 330ÂșC, to seek for every possible impact phenomenon and characterise the impact morphology. The impact dynamics were captured using a high-speed digital camera and the images were digitally processed. It was possible to observe the heat regimes for all fluids, as well as two additional regimes for the mixtures of 75% jet fuel - 25% HVO and 50% jet fuel - 50% HVO.A preocupação com o ambiente levou o ser humano a desenvolver novos combustĂ­veis alternativos para reduzir a poluição e mitigar a emissĂŁo de gases de efeito de estufa. O setor de transporte aĂ©reo e a queima de combustĂ­veis fĂłsseis Ă© responsĂĄvel por grande parte da poluição. Por conseguinte, introduzir novas formas sustentĂĄveis de fornecer energia, como os biocombustĂ­veis, Ă© de elevada importĂąncia. Contudo, de modo a tornar estes novos meios de energia mais eficientes e seguros, Ă© necessĂĄrio realizar estudos relativos Ă  injecção de combustĂ­veis nas cĂąmaras de combustĂŁo e ao impacto de gotas. Este estudo Ă© focado numa investigação experimental sobre o impacto de gotas numa superfĂ­cie sĂłlida quente. O principal objectivo deste trabalho Ă© analisar a influĂȘncia da temperatura da superfĂ­cie na morfologia do impacto de uma Ășnica gota e observar os possĂ­veis resultados. Para isso, nestes ensaios experimentais foram utilizadas misturas de Jet Fuel e HVO (Óleo Vegetal Hidroprocessado). Os fluidos utilizados foram: ĂĄgua (como grupo de controlo), 100% Jet A-1, 75% Jet A-1 e 25% NExBTL, 50% Jet A-1 e 50% de NExBTL, e 100% NExBTL. Estas misturas seguem os requisitos da aviação civil, no qual tĂȘm que conter um mĂ­nimo de 50% de jet fuel. O presente trabalho estuda os efeitos de impacto de uma gota em função da temperatura da superfĂ­cie para diferentes fluidos. A energia de impacto foi mantida constante. Portanto, o nĂșmero de Weber nesta experiĂȘncia foi fixado em W e = 320, tendo variado ou o diĂąmetro da gota ou a velocidade de impacto. AlĂ©m disso, foram escolhidas diferentes temperaturas da superfĂ­cie, que variam entre Tw = 25ÂșC e Tw = 330ÂșC, para procurar obter cada fenĂłmeno de impacto e caracterizar a morfologia do mesmo. As dinĂąmicas de impacto foram capturadas utilizando uma cĂąmara digital de alta velocidade e as imagens foram processadas digitalmente. Foi possĂ­vel observar os regimes de calor para todos os fluidos, bem como alguns adicionais para as misturas de 75% jet fuel - 25% HVO e 50% jet fuel - 50% HVO

    Light harvesting in solar cells using natural pigments from red fruits adsorbed to mesoporous TiO2

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    Nature has developed strategies to present us with a wide variety of colours, from the green of leaves to the bright colours seen in flowers. Anthocyanins are between these natural pigments that are responsible for the great diversity of colours seen in flowers and fruits. Anthocyanins have been used to sensitize titanium dioxide (TiO2) in Dye-Sensitized Solar Cells (DSSCs). DSSCs have become one of the most popular research topic in photovoltaic cells due to their low production costs when compared to other alternatives. DSSCs are inspired in what happens in nature during photosynthesis. A primary charge separation is achieved by means of a photoexcited dye capable of performing the electron injection into the conduction band of a wide band-gap semiconductor, usually TiO2. With this work we aimed to synthesize a novel mesoporous TiO2 structure as the semiconductor in order to increase the dye loading. We used natural occurring dyes such as anthocyanins and their synthetic flavylium relatives, as an alternative to the widely used metal complexes of Ru(II) which are expensive and are environmentally unsafe. This offers not only the chance to use safer dyes for DSSCs, but also to take profit of waste biological products, such as wine and olive oil production residues that are heavily loaded with anthocyanin dyes. We also performed a photodegradation study using TiO2 as the catalyst to degrade dye contaminants, such as those from the wine production waste, by photo-irradiation of the system in the visible region of the light spectrum. We were able to succeed in the synthesis of mesoporous TiO2 both powder and thin film, with a high capacity to load a large amount of dye. We proved the concept of photodegradation using TiO2 as catalyst. And finally, we show that wine production waste is a possible dye source to DSSCs application

    Impact of dietary supplements on reproductive function: Curcumin and Resveratrol

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    Tese de mestrado, Biologia Molecular e GenĂ©tica, Universidade de Lisboa, Faculdade de CiĂȘncias, 2019A prevalĂȘncia global da infertilidade feminina tem vindo a aumentar nas Ășltimas dĂ©cadas. Entre diversos fatores, a idade reprodutiva avançada das mulheres Ă© uma das principais razĂ”es que contribuem para o aumento desta condição. Com o objetivo de amenizar estes efeitos tem sido proposta a introdução na alimentação de suplementos com propriedades antioxidantes de forma a promover o aumento da fertilidade. Neste contexto Ă© cada vez maior a procura de substĂąncias naturais em detrimento de compostos sintĂ©ticos. Atualmente, a curcumina (CUR) e o resveratrol (RES), na sua forma pura ou em conjugação com outras substĂąncias naturais, sĂŁo dos suplementos alimentares mais procurados. A curcumina e o resveratrol sĂŁo dois polifenĂłis com propriedades antioxidantes e anti-inflamatĂłrias jĂĄ demonstradas em diferentes tipos de cĂ©lulas. A curcumina (1,7-bis-(4-hydroxy3-methoxyphenyl) -1,6-hepadiene-3,5-dione), Ă© o principal ingrediente ativo isolado das raĂ­zes da planta Curcuma Longa tambĂ©m conhecida por açafrĂŁo-da-terra, açafrĂŁo-da-Índia ou gengibre amarelo. A CUR, pigmento responsĂĄvel pela tonalidade alaranjada caracterĂ­stica da curcuma, alĂ©m de apresentar propriedades antioxidantes e anti-inflamatĂłrias, provoca a morte celular por apoptose em cĂ©lulas tumorais. Adicionalmente, a CUR tem sido correlacionada com a prevenção de doenças como a doença de Alzheimer, depressĂŁo, doenças cardiovasculares, artrite e outras doenças crĂłnicas relacionadas com o envelhecimento. Por outro lado, estudos in vitro utilizando CUR, sugerem uma diminuição na viabilidade das cĂ©lulas cancerĂ­genas, assim como uma diminuição da angiogĂ©nese. Para comprovar estes efeitos serĂĄ necessĂĄrio aumentar a investigação nesta ĂĄrea de modo a confirmar a relação entre a toma deste suplemento e um melhoramento na prevenção/combate do cancro. O resveratrol (3,5,4’-trihydroxystilbene) Ă© sintetizado por diversas plantas em resposta aos raios UV, toxinas, fungos ou agentes patogĂ©nicos. Este composto, encontrado principalmente em vinho tinto, cacau, amendoim ou mirtilos, apresenta atividades biolĂłgicas e farmacolĂłgicas que se revelaram eficazes na proteção cardiovascular e cerebral. Contudo, uma das maiores dificuldades no uso da CUR e do RES estĂĄ relacionada com a biodisponibilidade que apresentam. Estudos indicam, que os valores detetĂĄveis no plasma apĂłs o consumo de CUR ou RES sĂŁo bastante reduzidos, sendo a sua eliminação rĂĄpida e a absorção residual. Este trabalho surge com o objetivo de entender o efeito destes dois compostos no ciclo ovĂĄrico, sendo realizado com recurso a cĂ©lulas da granulosa. As cĂ©lulas da granulosa rodeiam o ovĂłcito e mantĂ©m uma relação direta com o mesmo atravĂ©s de troca de nutrientes e produção de hormonas necessĂĄrias Ă  sua manutenção e desenvolvimento. Entre outros fatores, defeitos nestas cĂ©lulas podem contribuir para casos de infertilidade feminina sendo pertinente o estudo da CUR e do RES nas suas principais funçÔes. Os principais objetivos deste projeto prendem-se com i) o estudo do impacto direto de diferentes concentraçÔes de CUR e RES na viabilidade das cĂ©lulas da granulosa ii) a avaliação de ambos os compostos ao nĂ­vel da proteção contra o stress oxidativo iii) com possĂ­veis alteraçÔes ao nĂ­vel da função hormonal destas cĂ©lulas. Deste modo, foi utilizada a linha celular COV434 com as quais se procedeu Ă  anĂĄlise do efeito de diferentes concentraçÔes de CUR e RES. Apesar da vasta utilização de linhas celulares em diversas ĂĄreas de investigação, devido ao seu papel de relevo no complemento de estudos in vivo e no estudo de processos celulares, estas podem diferir fenotĂ­pica e geneticamente do tecido de origem. Em contrapartida, culturas de cĂ©lulas primĂĄrias retĂȘm diversas caracterĂ­sticas e funçÔes observadas in vivo, sendo um valioso modelo na transição para a ĂĄrea clĂ­nica. ApĂłs ensaios com ambos os compostos na linha celular, procedeu-se a igual avaliação utilizando culturas primĂĄrias de cĂ©lulas da granulosa de pacientes submetidas a tratamentos de reprodução medicamente assistida (TRA). Durante a colheita dos ovĂłcitos, o lĂ­quido folicular foi recolhido e os ovĂłcitos isolados para posterior fertilização in vitro ou injeção citoplasmĂĄtica (ICSI). ApĂłs o consentimento informado das pacientes, o restante lĂ­quido folicular foi transportado para laboratĂłrio onde se procedeu ao isolamento e purificação das cĂ©lulas da granulosa. De acordo com os nossos resultados, os ensaios de viabilidade demonstram que a CUR exerce um efeito duplo. AtravĂ©s da realização de ensaios de MTT e LDH, verificamos que em baixas concentraçÔes, a CUR provoca um ligeiro aumento na viabilidade das cĂ©lulas da granulosa, enquanto que em concentraçÔes elevadas provoca necrose, a viabilidade diminui e a libertação de LDH aumenta em ambos os modelos celulares. Contudo, nas concentraçÔes de 1 e 5 ÎŒM de CUR, ocorre uma diminuição na viabilidade celular sem libertação de LDH, sugerindo apoptose. Este facto foi explorado atravĂ©s da anĂĄlise da morfologia, utilizando microscopia de contraste de fase, coloraçÔes de Giemsa e Höechst e anĂĄlise do potencial da membrana mitocondrial. Em seguida, foi avaliada a atividade da PARP-1 e das caspases -3/7 e caspase -9. Os resultados sugerem apoptose nas cĂ©lulas primĂĄrias da granulosa, contudo mais estudos sĂŁo necessĂĄrios. As espĂ©cies reativas de oxigĂ©nio (ROS) foram de igual modo analisadas, pois o aumento da sua produção estĂĄ associado a um incremento no stress oxidativo das cĂ©lulas, que se pode refletir na qualidade dos ovĂłcitos. ApĂłs tratamento das cĂ©lulas da granulosa com baixas concentraçÔes de CUR e posterior indução de stress com recurso ao hidroperĂłxido de terc-butila (TBHP), a produção de ROS foi verificada. Identificamos uma diminuição nos nĂ­veis de ROS nas cĂ©lulas previamente incubadas com CUR quando comparados com os nĂ­veis de ROS das cĂ©lulas tratadas isoladamente com o indutor de stress. Estes resultados enaltecem as propriedades antioxidantes deste composto. Contudo, apesar de nĂŁo se verificarem alteraçÔes na viabilidade celular apĂłs adição de baixas concentraçÔes de CUR, procedemos ao estudo da função hormonal das GC de modo a garantir que esta nĂŁo se encontra afetada. Foram identificadas diferenças na produção de estradiol e progesterona e na expressĂŁo dos genes associados, StAR, CYP11A1, 3ÎČ-HSD e aromatase (CYP19A1), que desempenham um papel chave na sĂ­ntese das hormonas. Com baixas concentraçÔes nĂŁo sĂŁo detetadas diferenças ao nĂ­vel da expressĂŁo dos genes estudados, contudo a concentraçÔes supra fisiolĂłgicas, a utilização de CUR sugere uma interferĂȘncia na sĂ­ntese de estradiol. No entanto, os resultados da adição de diferentes concentraçÔes de RES na linha celular nĂŁo sĂŁo concordantes com os obtidos nas cĂ©lulas primĂĄrias da granulosa, sugerindo que estas Ășltimas sĂŁo menos sensĂ­veis ao composto fenĂłlico. AlĂ©m disso, a anĂĄlise da produção de ROS, o estudo do potencial da membrana mitocondrial e os estudos morfolĂłgicos realizados, nĂŁo sugerem ocorrĂȘncia de apoptose nas cĂ©lulas da granulosa. O potencial antioxidante do RES foi igualmente avaliado e, tal como na CUR, nĂŁo verificamos alteraçÔes dos nĂ­veis basais de ROS. No entanto, sugere algum tipo de proteção das cĂ©lulas da granulosa apĂłs indução de stress. Por fim, no que diz respeito Ă  função hormonal das cĂ©lulas, os nossos resultados indicam que nĂŁo existem alteraçÔes nos nĂ­veis de estradiol e progesterona a baixas concentraçÔes, o que nĂŁo se verifica a altas doses de RES, que revelam um aumento do estradiol. Por conseguinte, estes resultados sugerem que o RES altera a função hormonal das cĂ©lulas da granulosa. Em sĂ­ntese, este estudo sugere que o consumo moderado de suplementos de RES e/ou CUR, promove melhoria na qualidade dos ovĂłcitos. No entanto, quando em conjunto com coadjuvantes, como Ă© o caso da piperina, a biodisponibilidade de ambos os compostos aumenta. O aumento da biodisponibilidade pode traduzir-se em consequĂȘncias negativas para as cĂ©lulas da granulosa, uma que vez que concentraçÔes elevadas de CUR e RES levam Ă  diminuição da viabilidade celular e comprometem a função hormonal.Global infertility prevalence has been increasing in recent decades. Among various factors, advanced reproductive age of women is a major contributor to the widening of this condition. Concerned women look for dietary supplements with antioxidant properties advertised as a natural way to increase fertility. Curcumin (CUR) and resveratrol (RES) are two highly acclaimed polyphenols with antioxidant and anti-inflammatory properties widely described in different cell types. Curcumin, isolated from the roots of the Curcuma Longa plant, is a yellow pigment commonly used in Asian countries, especially in India. In addition to its antioxidant and anti-inflammatory properties, CUR elicits apoptotic cell death as evidenced in some tumor cells. Resveratrol, in turn, is produced by plants in response to UV rays, toxins, fungal attacks or pathogens. It is mainly present in red wine, cocoa, peanuts or blueberries. In recent years, it has been extensively studied and its importance increased due to its biological and pharmacological activities that have proved to be effective in cardiovascular and brain protection. In this work, the effect of both compounds on granulosa cells (GC) was studied. GC surround the oocyte and maintain a direct contact with it through the nutrient exchange and hormone production necessary for its development. Their normal function is crucial, since defects in these cells can contribute to women infertility. For this purpose, COV434 cell line and primary human granulosa cells (hGC) cultures from patients undergoing assisted reproductive technology (ART) were used. During the experiments, GC were treated with different concentrations of CUR and RES (0.001-50ÎŒM) at different times (24-72h). Low concentrations of both compounds showed an increase on cell viability and did not exert visible changes on cell morphology. Likewise, they lead to a decrease in ROS formation after stress induction, suggesting a protective role of CUR and RES. Changes in hormonal levels were not observed at these doses. In contrast, high concentrations of both compounds triggered a reduction on cell viability, accompanied by LDH release, suggesting cytotoxic effects. Allied to the above results, high doses of CUR and RES affected hormonal function of GC. CUR has a more evident dose-response effect; however, at 1-5 ÎŒM a reduction on cell viability without LDH release was observed, suggesting a programmed cell death mechanism. This work reinforces the importance of dietary supplements, namely CUR and RES, on the functions of GC and, consequently, on reproductive success
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