Stochastic frontier approach to agricultural production including technical effects: the brazilian agricultural censures of 1995-1996 and 2006.

In this paper we analyze the impact of Embrapa’s research on the technical efficiencies of Brazilian farmers, particularly the poor. Using a stochastic frontier approach, we estimate a production function to obtain not only the technica efficiencies but also the elasticities of the key inputs. Our results indicate that Embrapa has generally had a positive effect on technical efficiencies, but there are still challenges ahead for Embrapa. Key among these challenges is the dissemination of its technology, which seems to be predominantly adopted by wealthier farmers. The low or absent use of modern inputs by poor farmers is highly detrimental of their ability to succeed

Assessing the determinants of rural income dispersion in Brazil.

This article has as its objective the analysis of rural income dispersion in Brazil. To this en we fit econometric regression models using the Gini index as the dependent variable, tecnology, and environmental, social and demographic indices as independent variables. The analysis is performed on a regional basis. The statistical approach uses fractional regression and generalized method of moments 9GMM) The tecnological variable crystallizes the production process uses county data collected from the Brazilian agricultural census of 2006. Tecnology is significant and dominates the relationship in all regions. The other covariates vary in regional intensity

Software architecture for YOLO, a creativity-stimulating robot

YOLO is a social robot designed and developed to stimulate creativity in children through storytelling activities. Children use it as a character in their stories. This article details the artificial intelligence software developed for YOLO. The implemented software schedules through several Creativity Behaviors to find the ones that stimulate creativity more effectively. YOLO can choose between convergent and divergent thinking techniques, two important processes of creative thought. These techniques were developed based on the psychological theories of creativity development and on research from creativity experts who work with children. Besides promoting creativity, this software allows the creation of Social Behaviors that enable the robot to behave as a believable character. We built 3 main social behavior parameters: Exuberant, Aloof, and Harmonious. These behaviors are meant to ease immersive play and the process of character creation. The 3 social behaviors were based on psychological theories of personality and developed using children's input during co-design studies. Overall, this work presents the design, development, and usage of social robots that might nurture intrinsic human abilities, such as the ability to be creative.info:eu-repo/semantics/publishedVersio

Substituição de culturas: uma abordagem empírica envolvendo cana-de-açúcar, soja, carne bovina e milho.

Com o objetivo de avaliar a variação relativa das áreas cultivadas de soja-cana-de-açúcar, pastagem-cana-de-açúcar, milho-cana-de-açúcar, soja-pastagem e soja-milho, em razão da variação dos respectivos preços relativos (no caso de pastagem, carne), da taxa de juros, da taxa de câmbio e do tempo, ajusta-se um modelo econométrico à variação de área agricultável, na família Cobb-Douglas. Medido pelo R2, o modelo ajustou-se bem aos dados. O exercício empírico é importante no atual contexto brasileiro, quando se conjecturam mudanças drásticas no perfil agrário do País, admitindo-se que a cana-de-açúcar substituirá lavouras que estão na base da alimentação dos consumidores, dada a demanda mundial por biocombustíveis. Coerente com a expectativa geral, a hipótese é de que os cultivos de soja, de milho e de pastagem estivessem sendo substituídos pelo cultivo da cana-de-açúcar, e isso implicaria sinal negativo para a variável tendência. A hipótese só não foi rejeitada para a variável tendência, no caso do milho-cana-deaçúcar, pois nos demais casos ela não tem o suporte dos dados. Na realidade, a soja é que tem substituído as demais lavouras, inclusive a de cana-de-açúcar. Especificamente no período avaliado (1994?2005), os preços internacionais relativos para milho-cana-de-açúcar, soja-cana-de-açúcar, carne-cana-de-açúcar e soja-carne não influenciaram as relações entre as respectivas áreas. A exceção é o caso soja-milho. O câmbio foi importante tanto para a relação milho-cana-deaçúcar, com elasticidade de 0,40%, como para a relação soja-milho, de 0,36%. Os juros, medidos pela taxa Selic, foram importantes no contexto das relações: soja?cana-de-açúcar, com elasticidade de 0,23%; pastagem?cana-de-açúcar, com elasticidade de 0,10% (marginalmente significante); e soja-pastagem, com elasticidade de 0,23%. A variável tendência é estatisticamente significante em todos os casos, exceto na relação pastagem-cana-de-açúcar e na relação soja-milho, nas quais foi omitida. O seu coeficiente mede a taxa instantânea de substituição de uma lavoura por outra. Tem-se o sinal esperado na relação milho-cana-de-açúcar, com taxa instantânea de -6,7%, o que indica que a cultura da cana-de-açúcar substituiu a do milho. E um sinal positivo nos seguintes cultivos: soja-cana-de-açúcar, 7,9%; soja-pastagem, 8,0%, o que indica que o da cana-de-açúcar vem sendo substituído. Reafirmando a conclusão, somente no caso do milho a cana-de-açúcar está substituindo uma dada lavoura. Nos demais casos, os dados não suportam a hipótese de substituição. Pelo contrário, indicam a perda de áreas de cultivo de cana-de-açúcar.Na publicação: Eliseu Alves

Complex phenotype of hypercholesterolaemia in a family with both ABCG8 and APOB mutations

Familial Hypercholesterolemia (FH) is the most common of all genetic hypercholesterolaemias with defects in LDLR, APOB and PCSK9 accounting for the majority of cases. However, there are other rare disorders like sitosterolaemia that can present the same phenotype. Both can cause premature atherosclerosis but have distinctive dietetic and therapeutic intervention.N/

Um modelo de produção para a agricultura brasileira e a importância da pesquisa da Embrapa.

Neste trabalho ajusta-se um modelo de fronteira estocástica para a agricultura brasileira com base em uma amostra representativa dos dados primários do censo agropecuário de 2006. O modelo é especificado com a combinação de erros normal-meia normal para as componentes aleatória e de ineficiência. A função de produção do modelo está definida na família Cobb-Douglas e engloba os insumos terra, trabalho e insumos tecnológicos. Para o censo agropecuário de 2006, a elasticidade dos insumos tecnológicos é dominante. Postula-se a presença de efeitos técnicos nas componentes de erro. Esses efeitos incluem diversas classes de renda, regiões, assistência técnica e a percepção sobre a importância da pesquisa da Embrapa na melhoria da renda dos produtores rurais. A presença de assistência técnica e as variáveis não categóricas, como a importância da Embrapa e a probabilidade de renda líquida positiva, influenciam positivamente a componente de eficiência técnica. Esses resultados persistem com a inclusão de observações representativas do censo agropecuário de 1995?1996.Na publicação: Eliseu Alves

Groove Pancreatitis with Biliary and Duodenal Stricture: An Unusual Cause of Obstructive Jaundice

INTRODUCTION: Groove pancreatitis is an uncommon cause of chronic pancreatitis that affects the groove anatomical area between the head of the pancreas, duodenum, and common bile duct. CLINICAL CASE: A 67-year-old man with frequent biliary colic and an alcohol consumption of 30-40 g/day was admitted to the hospital complaining of jaundice and pruritus. Laboratory analysis revealed cholestasis and the ultrasound scan showed intra-hepatic biliary ducts dilatation, middle third cystic dilatation of common bile duct, enlarged Wirsung and pancreatic atrophy. The magnetic resonance cholangiopancreatography showed imaging findings compatible with groove pancreatitis. An esophagogastroduodenoscopy later excluded duodenal neoplasia. He was submitted to a Roux-en-Y cholangiojejunostomy because of common bile duct stricture. Five months later a gastrojejunostomy was performed due to a duodenal stricture. The patient remains asymptomatic during follow-up. DISCUSSION: Groove pancreatitis is a benign cause of obstructive jaundice, whose main differential diagnosis is duodenal or pancreatic neoplasia. When this condition causes duodenal or biliary stricture, surgical treatment can be necessary.info:eu-repo/semantics/publishedVersio

Four Fermion Field Theories and the Chern-Simons Field: A Renormalization Group Study

In (2+1) dimensions, we consider the model of a $N$ flavor, two-component fermionic field interacting through a Chern-Simons field besides a four fermion self-interaction which consists of a linear combination of the Gross-Neveu and Thirring like terms. The four fermion interaction is not perturbatively renormalizable and the model is taken as an effective field theory in the region of low momenta. Using Zimmerman procedure for reducing coupling constants, it is verified that, for small values of the Chern-Simons parameter, the origin is an infrared stable fixed point but changes to ultraviolet stable as $\alpha$ becomes bigger than a critical $\alpha_c$. Composite operators are also analyzed and it is shown that a specific four fermion interaction has an improved ultraviolet behavior as $N$ increases.Comment: 9 pages, revte

Functionality of the paracoccidioides mating α-pheromone-receptor system

Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although no sexual cycle has been identified either in nature or under laboratory conditions. In the present work we detected low expression levels of the heterothallic MAT loci genes MAT1-1 and MAT1-2, the a-pheromone (PBa) gene, and the a- and apheromone receptor (PREB and PREA) genes in yeast and mycelia forms of several Paracoccidioides isolates. None of the genes were expressed in a mating type dependent manner. Stimulation of P. brasiliensis MAT1-2 strains with the synthetic a pheromone peptide failed to elicit transcriptional activation of MAT1-2, PREB or STE12, suggesting that the strains tested are insensitive to a-pheromone. In order to further evaluate the biological functionality of the pair a-pheromone and its receptor, we took advantage of the heterologous expression of these Paracoccidioides genes in the corresponding S. cerevisiae null mutants. We show that S. cerevisiae strains heterologously expressing PREB respond to Pba pheromone either isolated from Paracoccidioides culture supernatants or in its synthetic form, both by shmoo formation and by growth and cell cycle arrests. This allowed us to conclude that Paracoccidioides species secrete an active a-pheromone into the culture medium that is able to activate its cognate receptor. Moreover, expression of PREB or PBa in the corresponding null mutants of S. cerevisiae restored mating in these non-fertile strains. Taken together, our data demonstrate pheromone signaling activation by the Paracoccidioides a-pheromone through its receptor in this yeast model, which provides novel evidence for the existence of a functional mating signaling system in Paracoccidioides.MHJS and JFM were supported by Fundacão para a Ciência e Tecnologia (FCT) grants. This work was supported by a grant from FCT (PTDC/BIA-MIC/ 108309/2008)