Efecto de los herbicidas sobre el sistema inmune: una aproximación en peces

La exposición a compuestos xenobióticos, incluyendo herbicidas, en ambientes naturales, principalmente por prácticas agrícolas, ha llevado a cuestionar el impacto de estas prácticas sobre los organismos vivos. Se han demostrado efectos deletéreos de tal exposición en animales, tanto terrestres como acuáticos, siendo estos últimos los más afectados, pues actúan en muchos casos como receptores finales, por lixiviación, escorrentía o por aspersión directa de productos agroquímicos. Existen pocos trabajos que sustenten la inocuidad de los herbicidas para organismos acuáticos, específicamente peces y hay evidencia de inmunomodulación por diversos compuestos derivados de los compuestos xenobióticos. El objetivo del presente artículo es revisar y discutir posibles mecanismos de acción de los herbicidas en relación con alteraciones de la función inmune, así como enfatizar la importancia de los estudios en peces sobre el particular.Exposure to xenobiotics, including herbicides, in natural environments, mainly by agricultural practices has brought to question about the impact of these practices on live organism. Thus, deleterious effects of these exposures to animals, both terrestrial and aquatic have been proved, being the last one the most affected, since they function in some cases as final receptors, by lixiviation, run-off, or direct spray of agrochemical products. Still when, there are a few studies that support the innocuousness of herbicides to aquatic organisms, specifically fish, there is evidence of immunomodulation by diverse derivates compounds of them. The objective of the current article is to discuss about the possible mechanisms of action of herbicides related with alteration of immune function, as well as to emphasize the importance application of these studies in fish

Trade Reforms and Market Selection: Evidence from Manufacturing Plants in Colombia

We use plant output and input prices to decompose the profit margin into four parts: productivity, demand shocks, mark-ups and input costs. We find that each of these market fundamentals are important in explaining plant exit. We then use variation across sectors in tariff changes after the Colombian trade reform to assess whether the impact of market fundamentals on plant exit changed with increased international competition. We find that greater international competition magnifies the impact of productivity, and other market fundamentals, on plant exit. A dynamic simulation that compares the distribution of productivity with and without the trade reform shows that improvements in market selection from trade reform help to weed out the least productive plants and increase average productivity. In addition, we find that trade liberalization increases productivity of incumbent plants and improves the allocation of activity within industries.

Species composition and abundance of free-living turbellarians in three different wetlands in Southern Brazil

Free-living turbellarians mostly live in marine and freshwater environments, but they have been little considered in ecological studies. The coastal plain in southern Brazil harbors a diverse fauna and flora, but only a few studies have related environmental factors to the abundance, richness, and distribution of turbellarians. Hence, we analyzed the structure of turbellarian communities in floating vegetation in three differently sized limnic environments. We aimed to determine differences in abundance, density, and richness of turbellarians among these habitats in relation to environmental factors. We found 1,225 turbellarians (34 species) distributed among 6 taxa. The most abundant was Tricladida with 49.4% relative abundance; the remaining (Catenulida, Dalytyphloplanida, Macrostomorpha, Kalyptorhynchia, and Prorhynchida) were less abundant. We found no significant differences among population parameters and environments. Small shallow lakes are a potentially rich environment, while water channels are the richest environment. Larger shallow lakes are not very diverse for turbellarians. Similarities regarding turbellarian communities among close limnic systems could be explained by the connectivity of bodies of water that presents similar aquatic macrophytes and hydrological subsystems, while larger shallow lakes have a different community because they have their own contributing basin and could be influenced by other factors.publishedVersio

Creative destruction over the business cycle: a stochastic frontier analysis

[[abstract]]This paper examines the within-industry distributions of jobs created and destructed across plants in terms of technical efficiency, technical efficiency change, scale effect, and technical change. It further investigates how these distributions vary with economic activity. By applying the stochastic frontier analysis to plant-level longitudinal data on Taiwan’s 23 two-digit manufacturing industries spanning the period 1992–2003, we find that jobs created (destructed) are disproportionately clustered at plants with lower technical efficiency but higher rate of technical change. A fall in economic activities is associated with a statistically significant decrease (increase) in the fraction of newly created (destructed) jobs accounted for by plants with a higher rate of technical change, indicating that creative destruction is more pronounced during economic contractions.[[journaltype]]國外[[incitationindex]]SSCI[[ispeerreviewed]]Y[[countrycodes]]US

TOXICIDAD AGUDA Y LESIONES HISTOPATOLÓGICAS EN CACHAMA BLANCA (Piaractus brachypomus) EXPUESTAS A LA MEZCLA DE HERBICIDA ROUNDUP® MÁS SURFACTANTE COSMOFLUX® 411F

Objetivo. Determinar la concentración letal 50 (CL 50 ) y lesiones anatomopatológicas inducidas por la exposición a la mezcla del herbicida Roundup® más el surfactante Cosmoflux® 411F en juveniles de cachama blanca (Piaractus brachypomus). Materiales y métodos. Ejemplares de 44.5 ± 3.7 g de peso fueron expuestos por 96 h a varias concentraciones de la mezcla herbicida más surfactante. Se registró la mortalidad al cabo de las 96 h y se tomaron muestras de tejidos para evaluación histopatológica. Resultados. La CL 50 fue de 23.42 mg.l -1 para el Roundup® y de 0.19 mg.l -1 para el Cosmoflux® 411F (

Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobility.Die Farbgebung durch Carotinoide hat sich schon oft als ein geschlechtsspezifisches Signal für individuelle Qualität herausgestellt. Für unterschiedliche Tierarten hat man festgestellt, dass Individuen, die hellere, auf Carotinoiden basierende Farb-Signale aussenden, eine bessere Nahrungsaufnahme haben, sich schneller von Krankheiten erholen und allgemein in besserer körperlichen Verfassung sind. Beim Fichtenkreuzschnabel (Loxia curvirostra) wurde die Farbgebung auch mit verschiedenen Populationen in Verbindung gebracht, wobei die nord- und mitteleuropäischen Populationen als rötlicher beschrieben wurden als die des Mittelmeerraums. Eine Untersuchung in den Pyrenäen zeigte, dass Tiere mit längeren Flügeln eine offenbar geringere Überlebensrate und einen höheren Anteil an rötlichen Individuen aufwiesen, woraus zu schließen wäre, dass es sich um nomadisierende Vögel handeln könnte (die weite Strecken zurücklegen). Wenn die roten Fichtenkreuzschnäbel mobiler als die gelben und orangefarbenen sind, könnte ihre Überlebensrate mutmaßlich geringer sein. Aber in unserer Untersuchung lebten rötliche Männchen länger als andersgefärbte und fast doppelt so lang wie die gelblichen Männchen. Diese Ergebnisse deuten darauf hin, dass die rote Färbung mit höherwertigen Individuen verbunden ist, unabhängig von deren Mobilität

Mesozoic rock suites along western Philippines: Exposed proto-South China Sea fragments?

An ancient oceanic crustal leading edge east of mainland Asia, the proto-South China Sea crust, must have existed during the Mesozoic based on tectonic reconstructions that accounted for the presence of subducted slabs in the lower mantle and the exposed oceanic lithospheric fragments strewn in the Philippine and Bornean regions. Along the western seaboard of the Philippine archipelago, numerous Mesozoic ophiolites and associated lithologies do not appear to be genetically associated with the younger Paleogene-Neogene ocean basins that currently surround the islands. New sedimentological, paleomagnetic, paleontological, and isotopic age data that we generated are presented here, in combination with our previous results and those of others, to reassess the geological make-up of the western Philippine island arc system. We believe that the oceanic lithospheric fragments, associated melanges, and sedimentary rocks in this region are exhumed slivers of the proto-South China Sea ocean plate