Determinants of cash holdings on start-ups

Mestrado em FinançasEste estudo tem como objectivo analisar os determinantes da gestão de tesouraria, bem como as suas implicações ao nível das start-ups portuguesas. Recorrendo a uma base de dados que conjuga informação financeira com dados sobre empregado-empregador, para o período entre 2004 e 2009, ficando com uma amostra de 15,693 observações. Ao contrário de estudos anteriores, avaliámos a importância que a gestão de tesouraria assume nas start-ups, examinando como as características educacionais e demográficas dos fundadores estão associadas à sua gestão. Em termos da metodologia, iremos recorrer a uma análise Tobit, onde controlamos a nossa estimação através do ano de referência, industria e NUTS. É possível observar que a gestão de tesouraria nas start-ups é afectada positivamente pelas oportunidades de investimento, dívida de longo prazo e caracteristicas sócio-demográficas e educacionais do fundador. Por outro lado, a gestão de tesouraria nas star-ups é negativamente afectado pela dimensão, activos líquidos e dívida bancária. Para a análise ao nível das NUTS, é possível observar que as região de Lisboa, Centro e Açores apresentam as mesmas caracteristicas. Ao nível da análise por industria, temos que, a dimensão, os activos liquídos e a estrutura da dívida das start-ups está negativamente relacionado com a gestão de tesouraria. Para as caracteristicas do fundador, os níveis educacionais abaixo do nível educacional mais elevado apresentam um impacto negativo na gestão de tesouraria das start-ups. Podemos esperar que o Pecking Order, e a teoria do Trade-off, expliquem os determinantes da gestão de tesouraria das start-ups.The purpose of this study is to examine the determinants and the implications of cash holding on start-ups for a sample of Portuguese firms. We use a database that combines firm-level financial data with a matched employer-employee database, for the period between 2004 and 2009, presenting a sample of 15,693 observations. Unlike previous studies, we examine which start-ups and founders' educational and social-demographic characteristics are more likely to be associated with cash holdings. In terms of methodology, it is conducted a Tobit analysis where we control for year, industry and NUTS in the estimation of our model. It is possible to observe that start-ups cash holding levels are positively affected by investment opportunities, long term debt and founder's characteristics and the contrary for start-ups size, liquid assets substitutes and bank debt. When analyzing by NUTS, it is possible to see that the regions of Lisbon, Center and Azores present the same characteristics. Finally, at the industry level: size, liquid assets and debt maturity structure are negatively related with cash holdings across industries. While for founder's characteristics, the educational levels below the higher level of education have a negative impact over start-ups cash holding levels. We can conclude that the Trade-off Theory and the Pecking Order Theory are the ones that play the most important role in explaining the determinants of Portuguese firm's cash holdings

Parallel progressive precomputed radiance transfer

Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigation and distant environmental real time relighting of rigid scenes. Evaluating radiance transport is, however, a computationally very demanding task, which precludes PRT's utilization during the model design phase, since the user must wait for long periods of time before being able to light and navigate within the model. This paper proposes and validates an approach to provide visual feedback to the user as soon as possible, within PRT context. By resorting to parallel processing and progressive refinement, the user is quickly presented with a lower lighting resolution of the virtual model. This is then progressively refined by incrementally increasing the number of incident directions taken into account on transport computations. PRT is, however, a complex algorithm that requires frequent collective communications of huge volumes of data, thus constraining the maximum achievable speedup on a parallel system. This issue is analysed and an alternative workload distribution is proposed and evaluated on a 12 node dual processor cluster. The final solution ensures a good resource utilization rate, reducing response times from dozens of seconds to a few hundred milliseconds.Fundação para a Ciências e a Tecnologia - Project SEARCH - SErvices and Advanced Research Computing with HTC/HPC clusters

José Bonifácio, o economista

Quando todo o País, comemora o segundo centenário do nascimento dêste seu filho — ilustre e bravo — a nós nos parece que a melhor forma de expressar a nossa gratidão àquêle que foi chamado de "verdadeiro pai da pátria" será confessar-mos a nós mesmos que José Bonifácio quis, como base para um Brasil verdadeiramente independente, as reformas que nós ainda não realizamos ou que hesitamos em realizar.

Soil, Plant and Cattle Nutrient Dynamics on Pastures of the Western Amazon of Brazil

Cattle production on Brachiaria pastures is a primary use of cleared forestland in the western Brazilian Amazon. About 6.8 million hectares in the States of Acre and Rondônia have been deforested, where 75% of land is now grazed (IBGE, 1998). The principal pasture species are B. brizantha and B. decumbens with the latter in decline from spittlebug susceptibility (Deois incompleta; Gonçalves et al., 1996). The general pattern of pasture establishment in the Amazon basin includes felling and burning forest biomass, planting annual crops for one to three years (especially on small farms), and then seeding to grasses. The conversion of tropical forest to pasture, the effects of that process on soil properties, and pasture degradation outcomes have been studied in the eastern Amazon region ( Serrao et al., 1978; Reiners et al., 1994; Sanchez and Salinas, 1981; Buschbacher et al., 1987; Moraes et al., 1996) but not in the remote western region. Most findings showed an initial increase in soil cation concentrations with pasture establishment, except P, which declined to nearly undetectable amounts; and losses in pasture productivity after about five years with little management and poorly matched grasses (Serrao et al., 1978). The extent to which this outcome is due to poor management practices (e.g., inappropriate grass species) is unknown, and few studies in the region have examined the impacts of stocking rates, soil-plant nutrient relationships and burning frequencies on pasture degradation. Strategies that account for the cycling of major nutrients are needed to improve management of grasses and grass-legume associations. The objective of this study was to evaluate the hypothesis that low-input pasture use of land with Brachiaria spp. effectively sustains cattle production in the western Brazilian Amazon without deteriorating soil nutrient stocks . Three pasture land cover types (B. decumbens, B. brizantha and a grass association with Pueraria phaseoloides) were compared to primary forest and crops (maize and rice). Temporal (i.e., time post-deforestation) effects on the physical and chemical properties of soils and forages were evaluated. The nutrient pools in soil, plants and cattle herds and nutrients extracted in animal products were approximated to help understand the essential management to enhance cattle productivity and to avoid land degradation

Wastewater Electrolysis for Hydrogen Production

Due to its highest gravimetric energy density, H2 has been regarded as the preferred clean-energy carrier, with potentially environmentally-friendly production through the solar-assisted WS. Since human activities generate enormous amounts of WW, H2 production from this new resource has gained attention as an emergent technology. This paper addresses the most relevant and current aspects of H2 production from WWEL, and electricity generation from RES. In this sense, the state of art of H2 production, especially from WS, is presented here, as well as the main approaches to electricity generation from RES, with the greatest potential for viability. A new approach on this matter, which is part of the work that is being developed by the authors of this study, was also herein presented.This research was funded by the Portuguese Foundation for Science and Technology (FCT), grant number UIDP/05567/2020.info:eu-repo/semantics/publishedVersio

Nutrient status of cattle grazing systems in the western brazilian Amazon.

Low-input cultivated pastures to feed cattle have dominated land use after forest clearing for decades in the western Brazilian Amazon. This study was undertaken to help understand the inherent nutrient supply dynamics underwriting cattle performance on three farms in the state of Acre. We assessed soil chemical and physical properties associated over time with different land uses following forest clearing. This information permitted specifying a conceptual model of nutrient stocks and flows under the observed grazing system, which produced insights about the dynamics of soil nutrient degradation. Above ground forage mass, topsoil nutrient concentrations and soil bulk density were measured. Land covers were Brachiaria spp. grasses, a grass-Pueraria phaseoloides mix, cropland and forest. Most soil nutrient parameters initially decreased after clearing, gradually recovering over time with grass-only pastures; however, 20 yr-old pastures had 20% less forage mass. Most pasture system nutrients on these farms resided in topsoil and roots, where large stocks of mature forage supported soil fertility with recycled nutrients from litter. Estimates of partial topsoil nutrient balances were negative. This suggested that corresponding nutrient stocks and the accumulation of forage mass were probably maintained primarily through the sum of inflows from cattle excreta, the subsoil, soil organic matter, and litter mineralization with scant input of commercial fertilizer. Therefore, herd management to increase animal system productivity via higher stocking rates on vegetatively younger forage requires monitoring of nutrient stocks and flows and fertilization that assures replenishment of the nutrients extracted. Otherwise, rapid depletion of soil nutrient stocks will lead to system degradation and failure

Mapeamento de áreas de risco de deslizamento de solo e técnicas de prevenção no Município de Bragança Paulista com cálculos detalhados para aplicação de muro de arrimo de gabião / Mapping soil sliding risk areas and prevention techniques in the City of Bragança Paulista with detailed calculations for application of gabion retaining wall

O aumento populacional vem acarretando em ações antrópicas cada vez mais irresponsáveis intensificando a fragilidade do planeta. Por meio de técnica, o ser humano usa o conhecimento que tem da natureza a favor de seus próprios interesses, mas nem sempre atua de forma a respeitar o equilíbrio natural, provocando dessa forma a degradação ambiental. Essa interferência de caráter irresponsável somado as intempéries naturais resultam em desastres ambientais. Um fato que vem chamando a atenção é o aumento do registro de deslizamento de solo, geralmente em áreas habitadas inadequadamente, gerando impactos ambientais, sociais, econômicos e, infelizmente, perda de vidas. Na busca por conhecer as fragilidades e potencialidades de um local, este artigo trata-se da realização de um levantamento de áreas de risco no município de Bragança Paulista que já tenham registro de ocorrência ou que sejam suscetíveis a deslizamento de solo com características indicadas a receberem a aplicação de métodos de contenção que atendam aos objetivos de minimização do risco. Após uma triagem das informações, uma área de risco foi indicada para estudo aprofundado da técnica considerada eficiente para minimização do risco: muro de arrimo de gabião. Os cálculos realizados nesta etapa contribuíram para a geração de uma apostila resumida, mas detalhada, dos cálculos a fim de auxiliar outros estudantes

Influence of the enclosure, polishing and period of storage, about the roughness of the acrylic resins in the making of ocular prosthetics

A proposta desse estudo foi avaliar a rugosidade de resinas acrílicas próprias para confecção de próteses oculares, submetidas a dois diferentes métodos de inclusão e polimento, antes e após 60 dias de armazenagem. Foram confeccionados 24 corpos-de-prova, obtidos a partir de discos em resina acrílica incolor confeccionados em prensa semi-automática. Os discos foram incluídos em muflas próprias para microondas, utilizando dois diferentes tipos de materiais para revestimento, gesso especial e silicone de condensação. Após a presa final do gesso, as muflas foram abertas, os discos retirados e a resina prensada e polimerizada em forno microondas. Após o resfriamento natural das muflas, os corpos-de-prova foram desincluídos e submetidos ao acabamento e polimento. Dos 24 corpos-de-prova obtidos, 12 receberam polimento mecânico e restante polimento químico. Os corpos-de-prova foram submetidos ao teste de rugosidade de superfície, antes e após um período de armazenagem de 60 dias, utilizando um rugosímetro digital portátil modelo RP100 (Tonka Sul Americana Ltda, Brasil). Para cada corpo-de-prova foram realizadas 3 leituras que posteriormente foram transformadas em valores médios. Os resultados obtidos foram avaliados utilizando análise de variância seguido pelo teste de Tukey em nível de 5% de significância. Em todos os grupos houve um aumento na rugosidade superficial após 60 dias de armazenagem, porém estes valores só foram estatisticamente significantes para os corpos-de-prova polidos quimicamente. O grupo silicone proporcionou menores valores de rugosidade para os grupos quimicamente polidos. Independente do polimento empregado e do tempo de armazenagem, a inclusão com gesso proporcionou maiores valores de rugosidade superficial. ____________________________________________________________________________________ ABSTRACTThe proposal of that study was evaluate to roughness of own acrylic resins for making of eye prosthetics, submitted to two different approaches of enclosure and polishing, before and after 60 days of storage. They were concocted 24 samples, obtained from disks in colorless acrylic resin concocted in are-automatic press. The disks were included in muflas own for microwave, utilizing two different kinds of stuff for covering, special plaster and silicone of condensation. After final prey of the plaster, the muflas were open, the secluded disks and the resin presses and cured in oven microwave. After the natural cooling of the muflas, the samples were desincluídos and submitted to the finish and scouring. The 24 samples obtained, 12 received remaining mechanical and chemical polishing. The samples were submitted to the test of roughness of surface, before and after a period of storage of 60 days, utilizing a roughness readings digital portable model RP100 (Tonka South American Ltd, Protection, Brazil). For each samples were carried out 3 readings that sub -sequently were transformed in medium values. The results obtained were evaluated utilizing variance analysis followed by the test of Tukey in level of 5% of significance. In all of the groups had an increase in the roughness after 60 days of storage, however these alone values were statistically significant for the polished chemically. The group silicone provided decrease values of roughness for the chemically polite groups. Independent of the employed scouring and of the time of storage, the enclosure with plaster provided increase roughness values

SISTEMAS DE APOIO A EDUCAÇÃO A DISTÂNCIA: UMA EXPERIÊNCIA NA SEDIS/UFRN

Este artigo apresenta dois sistemas de informação implementados na Secretaria de Educação a Distância da Universidade Federal do Rio Grande do Norte - SEDIS/UFRN para gerenciar as informações que compõem a Educação a distância, relativas ao planejamento do semestre letivo e ao suporte de Tecnologia da Informação - TI. A metodologia adotada foi uma adaptação do ciclo de vida tradicional do desenvolvimento de sistemas de informação. A estratégia de pesquisa foi um estudo de caso da utilização do sistema pelos funcionários, professores, tutores e coordenadores que atuam, direta ou indiretamente, nos cursos de graduação a distância da Secretaria de Educação a Distância - SEDIS/UFRN. Considera-se que a solução adotada foi capaz de apoiar à gestão das informações, visto que direcionou os esforços para a prestação de serviços de maior qualidade, alinhados às exigências dos participantes da educação a distância