Ontogenetic dietary changes in male South American fur seals Arctocephalus australis in northern and central Patagonia, Argentina.

This study assessed ontogenetic dietary changes in male South American fur seals Arctocephalus australis in northern and central Patagonia (Argentina) using stable isotope ratios (δ15 N and δ13 C) in vibrissae and bones. Sucking pups were characterised by higher δ15 N values and lower δ13 C values than older specimens. Weaning was associated with a marked drop of δ15 N values, both in bone and vibrissae. Such a drop was inconsistent with the consumption of local prey and may reveal movement to distant foraging grounds or physiological changes associated with either fasting or rapid growth. Stable isotope ratios indicated that juveniles fed more pelagically than subadults and adults, but that there were no major differences between the 2 latter age categories. As subadults and adults are rather similar in body mass and are much larger than juveniles, body mass may play a role in the ontogenetic dietary changes reported. Nevertheless, demersal benthic prey were always scarce in the diet of male fur seals, which relied primarily on Argentine shortfin squid and small pelagic fish throughout life, though adults also consumed large amounts of decapod crustaceans available at shallow depths. Vibrissae did not reveal regular oscillations of δ15 N or δ13 C, except in 1 individual. Thus, male fur seals from northern and central Patagonia do not appear to migrate regularly between isotopically distinct areas, although nomadic displacements cannot be ruled out.

Sexual dimorphism of sonic apparatus and extreme intersexual variation of sounds in Ophidion rochei (Ophidiidae): first evidence of a tight relationship between morphology and sound characteristics in Ophidiidae

Many Ophidiidae are active in dark environments and display complex sonic apparatus morphologies. However, sound recordings are scarce and little is known about acoustic communication in this family. This paper focuses on Ophidion rochei which is known to display an important sexual dimorphism in swimbladder and anterior skeleton. The aims of this study were to compare the sound producing morphology, and the resulting sounds in juveniles, females and males of O. rochei.Results: Males, females, and juveniles possessed different morphotypes. Females and juveniles contrasted with males because they possessed dramatic differences in morphology of their sonic muscles, swimbladder, supraoccipital crest, and first vertebrae and associated ribs. Further, they lacked the ‘rocker bone’ typically found in males. Sounds from each morphotype were highly divergent. Males generally produced non harmonic, multiple-pulsed sounds that lasted for several seconds (3.5 ± 1.3 s) with a pulse period of ca. 100 ms. Juvenile and female sounds were recorded for the first time in ophidiids. Female sounds were harmonic, had shorter pulse period (±3.7 ms), and never exceeded a few dozen milliseconds (18 ± 11 ms). Moreover, unlike male sounds, female sounds did not have alternating long and short pulse periods. Juvenile sounds were weaker but appear to be similar to female sounds.Conclusions: Although it is not possible to distinguish externally male from female in O. rochei, they show a sonic apparatus and sounds that are dramatically different. This difference is likely due to their nocturnal habits that may have favored the evolution of internal secondary sexual characters that help to distinguish males from females and that could facilitate mate choice by females. Moreover, the comparison of different morphotypes in this study shows that these morphological differences result from a peramorphosis that takes place during the development of the gonads

A vueltas con las ONG: perspectivas teóricas sobre su papel en el proceso político

El escaso diálogo entre perspectivas teóricas complica un análisis sistemático sobre el papel de las ONG en el proceso político y más en concreto en las políticas públicas. El objetivo de este artículo es hacer una revisión de los diferentes enfoques sobre las ONG utilizados en la ciencia política y señalar algunas de las consecuencias de la fragmentación teórica. Se constata que las perspectivas de la sociedad civil, tercer sector, movimientos sociales y grupos de interés analizan esencialmente el mismo fenómeno: la acción colectiva a través de organizaciones de ciudadanos que defienden una causa concreta pero centrándose en diferentes aspectos de su función en el proceso político y en la definición de las políticas. Finalmente, se propone una definición operativa de las ONG a partir de los enfoques analizados.

Control del bienestar fetal: monitorización biofísica anteparto

En este artículo se presenta una actualización sobre el control del bienestar fetal anteparto, que incluye la monitorización biofísica con el test no estresante y el test estresante y su valoración. Se describen los parámetros de la frecuencia cardiaca fetal - la línea de base, la variabilidad y los ascensos transitorios de la frecuencia cardiaca fetal - en relación con los movimientos fetales, su significado clínico y la actuación que deriva del mismo.

Control del bienestar fetal: monitorización biofísica anteparto

En este artículo se presenta una actualización sobre el control del bienestar fetal anteparto, que incluye la monitorización biofísica con el test no estresante y el test estresante y su valoración. Se describen los parámetros de la frecuencia cardiaca fetal - la línea de base, la variabilidad y los ascensos transitorios de la frecuencia cardiaca fetal - en relación con los movimientos fetales, su significado clínico y la actuación que deriva del mismo.

Control del bienestar fetal: monitorización biofísica anteparto

En este artículo se presenta una actualización sobre el control del bienestar fetal anteparto, que incluye la monitorización biofísica con el test no estresante y el test estresante y su valoración. Se describen los parámetros de la frecuencia cardiaca fetal - la línea de base, la variabilidad y los ascensos transitorios de la frecuencia cardiaca fetal - en relación con los movimientos fetales, su significado clínico y la actuación que deriva del mismo.