Abstract Natural products, specifically plant extracts with biological activity and the ability to act as botanical biopesticides are often mistakenly considered nontoxic. Scientific evidence indicates the contrary, and for this reason, the objective of this work was to evaluate the toxicity of extracts obtained from Petiveria alliacea L. (Caryophyllales, Phytolaccaceae) using Daphnia magna Straus (Cladocera, Daphniidae) as a bioindicator to identify the plant extracts and the respective concentrations that present the highest toxicity. Leaves of P. alliacea were collected in the Peruvian amazone. From this material, three types of extract (hexane, ethanolic and aqueous) were prepared, which were used in the bioassays with D. magna to find the least toxic extract. Acute toxicity bioassays with D. magna during 48 h of exposure to hexane, ethanolic, and aqueous extracts yielded median lethal concentration (LC50) values of 26.9, 230.6, and 657.9 mg L-1, respectively. The aqueous extract presented the lowest toxicity, causing minimal D. magna mortality in the range of 6.67 to 13.33% at concentrations of 10 and 100 mg L-1. This result enables the efficient use of this plant species in a sustainable manner with a minimal environmental impact for the future development of natural products for pest control. nontoxic contrary reason L Caryophyllales, Caryophyllales (Caryophyllales Phytolaccaceae Cladocera, Cladocera (Cladocera Daphniidae P amazone material hexane (hexane prepared D 4 LC50 LC (LC50 269 26 9 26.9 2306 230 6 230.6 6579 657 657. L1, L1 1, 1 L-1 respectively 667 67 6.6 1333 13 33 13.33 L1. 1. control LC5 (LC5 2 26. 23 230. 65 L- 66 6. 133 3 13.3 (LC 13.

Resumo A utilização de produtos naturais, especificamente extratos vegetais com atividade biológica e capacidade de atuar como biopraguicidas botânicos, é muitas vezes erroneamente considerada não tóxica. Evidências científicas demonstram o contrário e por isso o objetivo deste trabalho consistiu na avaliação da toxicidade de extratos obtidos de Petiveria alliacea L. (Caryophyllales, Phytolaccaceae) com a utilização de Daphnia magna Straus (Cladocera, Daphniidae) como bioindicador, que permitiu descartar os extratos vegetais e as respectivas concentrações que apresentaram maior toxicidade. As folhas de P. alliacea foram coletadas na Amazônia peruana. A partir deste material, foram preparados três tipos de extrato − hexânico, etanólico e aquoso −, que foram utilizados nos bioensaios com D. magna a fim de encontrar o extrato menos tóxico. Os bioensaios de toxicidade aguda com D. magna durante 48 h de exposição aos extratos hexânico, etanólico e aquoso permitiram estabelecer os valores da Concentração Letal Média (CL50) de 26,9; 230,6 e 657,9 mg L-1, respectivamente. O extrato aquoso apresentou a menor toxicidade, causando percentuais mínimos de mortalidade de D. magna na faixa de 6,7 a 13,3% nas concentrações de 10 e 100 mg L-1. Estes resultados possibilitam o uso eficiente das espécies vegetais de forma sustentável e com mínimo impacto ambiental para o futuro desenvolvimento de produtos naturais para controle de pragas. botânicos tóxica L Caryophyllales, Caryophyllales (Caryophyllales Phytolaccaceae Cladocera, Cladocera (Cladocera Daphniidae bioindicador P peruana material hexânico D tóxico 4 CL50 CL (CL50 26,9 269 26 9 2306 230 6 230, 6579 657 657, L1, L1 1, 1 L-1 respectivamente 67 7 6, 133 13 3 13,3 L1. 1. pragas CL5 (CL5 26, 2 23 65 L- 13, (CL

Abstract: The Wind Farm Layout Problem (WFLP) consists in the placement of eolic generators (either in a grid, or at any position) into a delimited terrain. Several factors are taken into account to solve the WFLP, which include produced energy, costs - environmental, installation, maintenance, etc-, average useful life of turbines, among other. Likewise, optimization techniques involve the use of one or more objective functions, considering traditional as well as evolutionary approaches. Differential Evolution (DE) is an algorithm proposed for global optimization, whose operators are both simple to program and to utilize, still providing good convergence properties. The original authors of DE suggested its first five variants, which are: best/1/bin, best/2/bin, current − to − best/1/bin, rand/1/bin, and rand/2/bin. In this article it is proposed the comparison of five DE variants when they are used to solve 25 different instances of the WFLP; experimental results show that DE/best/1/bin outperforms the remaining algorithms in terms of convergence velocity as well as in the quality of the obtained wind-farm.

Bone Morphogenetic Protein 15 (BMP15), also known as Growth and Differentiation Factor 9B (GDF9B), is a member of the superfamily of Transforming Growth Factor β (TGFβ) and it expression in the oocyte is essential for follicular development and growth. Polymorphisms in the BMP15 gene are associated to the increase in ovulation rate or prolificacy in some sheep breeds. The objectives of this study were to determine the FecX G, FecX L and FecX H polymorphisms with a mutation of a single base (SNP- single nucleotide polymorphisms) on the BMP15 gene, and to estimate the association of the three polymorphisms with the lambing type in Pelibuey sheep. Blood samples were taken from the jugular vein of 253 adult Pelibuey ewes in reproductive age to determine the SNPs, according to the most probable producing ability (MPPA) in prolificacy. Through the tetraprimer ARMS-PCR technique (Amplification Refractory Mutation System-Polymerase Chain Reaction), the polymorphisms were determined for the first time in Pelibuey sheep. Of the 253 ewes, 1050 births were used, where the wild (CC) and mutated (TT) homozygous genotypes of polymorphism FecX G with 45% and 43%, respectively, and the wild (GG) and mutated (AA) homozygous genotype of polymorphism FecX L with 66% and 29%, respectively, were associated to a higher number of double lambing (p≤0.01). In polymorphism FecX H only CC genotype was found, with 52% double lambing (p≤0.01). In conclusion, polymorphisms FecX G and FecX L of the BMP15 gene were determined for the first time in Pelibuey ewes, and they are associated to a higher number of double lambing.

La proteína 15 morfogénica ósea (BMP15), también conocida como factor 9B de crecimiento y diferenciación (GDF9B), es miembro de la superfamilia de factores β de crecimiento (TGFβ) y su expresión en el ovocito es esencial para el desarrollo y crecimiento folicular. Polimorfismos en el gen BMP15 están asociados con el aumento de tasa ovulatoria o prolificidad en algunas razas de ovinos. Los objetivos del presente estudio fueron determinar los polimorfismos FecX G, FecX L y FecX H con una mutación de una sola base (SNP) en el gen BMP15, y estimar la asociación de los tres polimorfismos con el tipo de parto en ovejas Pelibuey. En 253 ovejas Pelibuey adultas en edad reproductiva se tomaron muestras sanguíneas de la vena yugular para determinar los SNPs, de acuerdo con la mejor aptitud de producción probable (MPPA) de prolificidad. Mediante la técnica tetraprimer ARMS-PCR (Amplification Refractory Mutation System-Polymerase Chain Reaction), se determinaron por primera vez los polimorfismos en las ovejas Pelibuey. De las 253 ovejas se usaron 1050 partos, donde los genotipos homocigoto silvestre (CC) y mutado (TT) del polimorfismo FecX G con 45% y 43%, respectivamente, y el homocigoto silvestre (GG) y mutado (AA) del polimorfismo FecX L con 66 % y 29%, respectivamente, se asociaron con un número mayor de partos dobles (p≤0.01). En el polimorfismo FecX H sólo se encontró el genotipo CC con 52% de parto doble (p≤0.01). En conclusión, los polimorfismos FecX G y FecX L del gen BMP15 fueron determinados por primera vez en ovejas Pelibuey, y están asociados con un número mayor de tipo de parto doble.

We formulate mathematically the process of pair production in electromagnetic fields for spinless particles. We compute the probability that n pairs are created in the semiclassical approximation, and herein we prove that the pair creation phenomenon is a stochastic Poisson process. Finally, we prove rigorously and interpret suitably the Schwinger formula.

Damos la formulación matemática del proceso de creación de pares de partículas sin spin en campos electromagnéticos. Calculamos la probabilidad de que se creen n pares en la aproximación semiclásica, y probamos, en esta aproximación, que la creación de pares es un proceso estocástico de Poisson. Finalmente, damos una demostración rigurosa y una interpretación correcta de la fórmula de Schwinger.

In this work we study the number of produced pairs in an electric field using the semiclassical aproach. We see that the stochastic process N(t)="net number of produced pairs at time t", is an stochastic Poisson process with expected value (αε (t))/(64mc²), where α is the fine structure constant and ε (t) is the energy of the electric field at time t.

En este trabajo estudiamos el número de pares creados en un campo eléctrico usando la aproximación semiclásica. Veremos que en la aproximación semiclásica el proceso estocástico N(t)= "número de pares creados en el instante t", es un proceso estocástico de Poisson con esperanza (αε(t))/(64mc²), donde α es la constante de estructura fina y ε(t) es la energía del campo eléctrico en el instante t.