Resumo A composição de macro endoparasitas associada com o lagarto Norops fuscoauratus (Squamata) foi analisada em duas localidades da Mata Atlântica no nordeste do Brasil, entre dezembro de 2012 e julho de 2015. 74 espécimes foram examinados e cinco espécies de helmintos foram encontradas, sendo: (a) para a população de Pernambuco: Cistacanto (Prevalência=37.5%), Physaloptera retusa Rudolphi, 1819 (Prevalência=4.16%), larva de platelminto (Prevalência=2.08%), Rhabdias sp. (Prevalência =2.08%) e Strongyluris oscari Travassos, 1923 (Prevalência =2.08%) e (b) Alagoas: S. oscari (Prevalência=17.85%) e Rhabdias sp. (Prevalência =3.57%). As diferenças na composição dos endoparasitas nas duas populações pode ser atribuída as individualidades dos ambientes ocupados por esses lagartos. O período de coleta não influenciou na abundância de parasitas, mas quando associado com o sexo, houve uma correlação positiva com a abundância de helmintos, com mais fêmeas do que machos, infectadas na estação chuvosa.

Abstract The composition of macro endoparasites associated with the lizard Norops fuscoauratus (Squamata) was analysed in two localities in the Atlantic Forest on the northeast of Brazil between December 2012 and July 2015. 74 specimens of N. fuscoauratus were examined and five species of helminths were reported, being: (a) for the population of Pernambuco: Cystacanth (Prevalence=37.5%), Physaloptera retusa Rudolphi, 1819 (Prevalence=4.16%), larva of flatworm (Prevalence=2.08%), Rhabdias sp. (Prevalence=2.08%) and Strongyluris oscari Travassos, 1923 (Prevalence=2.08%), and (b) of Alagoas: S. oscari (Prevalence=17.85%) and Rhabdias sp. (Prevalence=3.57%). The differences in the composition of endoparasites in the two populations are attributed to individualities of environments occupied by the lizards. The collection period does not influence the abundance of parasites, but when associated with sex, there was a positive correlation with the abundance of helminths, with more females than males being infected with parasites in the rainy season.

En España, debido a las prácticas agrícolas, el 13 % del territorio ha sido declarado vulnerable a la contaminación del agua por nitratos. Para mitigar los impactos ambientales generados por el nitrógeno, se ha construido un sistema híbrido de humedales artificiales gracias al proyecto europeo LIFE REAGRITECH. El prototipo ha sido pensado como un sistema compacto, modular y móvil, automatizado y operado de forma remota. La monitorización del sistema producirá conocimientos valiosos para la Administración Pública, los agricultores, investigadores y universidades, y proporcionará información útil para mejorar la toma de decisiones con el fin de preservar los recursos hídricos y el medio ambiente. El proyecto REAGRITECH tiene grandes perspectivas de futuro en el campo de la agricultura en Europa y en Colombia.

Due to the agricultural practices in Spain, 13% of the entire territory has been declared as vulnerable to nitrate-polluted water. In order to mitigate the environmental impact caused by nitrogen, a hybrid system of artificial wetlands has been engineered thanks to the European project known as LIFE REAGRITECH. The prototype has been thought as a compact, modular, and portable system, automated and operated in a remote manner. Monitoring of the system will result in valuable knowledge for public management, farmers, researchers, and universities, and it will provide useful information intended to improve the decision-making process as a way of preserving water resources and environment. Project REAGRITECH offers significant future perspectives in the field of agriculture in Europe and in Colombia as well.

Apresentamos uma equação de balanço do momento eletromagnético deduzida diretamente das equações de Maxwell. Esta equação contém uma densidade de força, por nós chamada de densidade de força de Maxwell, que generaliza aquela de Lorentz, incluindo neste caso os campos totais e não apenas os externos, bem como distribuições arbitrárias de cargas e correntes. Como teste desta equação deduzimos as forças de densidade magnetostática e eletrostática de Helmholtz para o caso de gases. Estas deduções são úteis para estudantes avançados de graduação e pós-graduação, bem como especialistas interessados em aspectos conceituais do eletromagnetismo.

We present a momentum balance equation derived directly from Maxwell's equations. This equation contains a force density, which we call Maxwell's force density, which generalizes the Lorentz force density, now including total fields rather than only external fields, and arbitrary charge and current distributions. As a test for this balance equation we derive for gases the electrostatic and magnetostatic Helmholtz force densities. This deduction will be useful for advanced undergraduates and graduate students, as well as for specialists interested in the conceptual aspects of electromagnetism.

The motion of a falling drop whose mass grows by accretion is studied with Newtonian methods to the point of finding the position as a function of time. The equation of motion applied is the equation of motion of continuum mechanics in its Eulerian or space formulation. We study three examples of laws of accretion: mass growing linearly with time, mass growing linearly with the surface of the drop and mass growing proportionally to the product of surface and velocity. These examples are sometimes left as exercises, without further discussion, asking only for v(z), or the final velocity. We also show that the solutions have the correct limit of a particle of constant mass in free fall and of such a particle with friction linear in the velocity.

Se estudia, mediante métodos Newtonianos, el movimiento de una gota que cae y cuya masa crece por acreción; se encuentra detalladamente la posición como función del tiempo. La ecuación de movimiento aplicada es la ecuación de movimiento de la mecánica de medios contínuos en su forma Euleriana o espacial. Estudiamos tres ejemplos de leyes de acreción: masa incrementándose linealmente con el tiempo, masa incrementándose propocionalmente a la superficie de la gota e incremento de la masa proporcional al producto de la superficie por la velocidad. También mostramos que las soluciones tienen el límite correcto, el de una partícula, con masa constante, en caída libre y el de esa partícula con fricción lineal en la velocidad.

The motion of a falling drop whose mass grows by accretion is studied with canonical methods. This approach requires the introduction of S-equivalent non natural Lagrangians. That is, we have to consider Lagrangians that give rise to equations of motion that are not exactly the same as the equations of interest, but anyway they share the same solutions. We study three examples of laws of accretion: mass growing linearly with time, mass growing linearly with the surface of the drop, and mass growing proportionally to the product of surface and velocity of the drop. In all cases we recover the results obtained by means of the Newtonian methods, which we expose in table I.

Se estudia, mediante métodos canónicos, la caida de una gota cuya masa crece por acreción. Este enfoque requiere la introducción de Lagrangianos S-equivalentes, no naturales. Esto es, tenemos que considerar Lagrangianos que conducen a ecuaciones de movimiento que no son exáctamente las mismas que las de interés, pero que comparten con ellas las mismas soluciones. Estudiamos tres ejemplos de leyes de acreción: incremento lineal de la masa con el tiempo, incremento de la masa proporcional a la superficie de la gota, e incremento proporcional al producto de la superficie de la gota por la velocidad de la misma. En todos los casos recobramos los resultados obtenidos mediante los métodos Newtonianos, los cuales presentamos en la tabla I.