Search results for "TACE"
showing 10 items of 739 documents
Pleistocene allopatric differentiation followed by recent range expansion explains the distribution and molecular diversity of two congeneric crustac…
2021
AbstractPleistocene glaciations had a tremendous impact on the biota across the Palaearctic, resulting in strong phylogeographic signals of range contraction and rapid postglacial recolonization of the deglaciated areas. Here, we explore the diversity patterns and history of two sibling species of passively dispersing taxa typical of temporary ponds, fairy shrimps (Anostraca). We combine mitochondrial (COI) and nuclear (ITS2 and 18S) markers to conduct a range-wide phylogeographic study including 56 populations of Branchinecta ferox and Branchinecta orientalis in the Palaearctic. Specifically, we investigate whether their largely overlapping ranges in Europe resulted from allopatric differe…
Positive density-dependent growth supports costs sharing hypothesis and population density sensing in a manipulative parasite.
2017
SUMMARYParasites manipulate their hosts’ phenotype to increase their own fitness. Like any evolutionary adaptation, parasitic manipulations should be costly. Though it is difficult to measure costs of the manipulation directly, they can be evaluated using an indirect approach. For instance, theory suggests that as the parasite infrapopulation grows, the investment of individual parasites in host manipulation decreases, because of cost sharing. Another assumption is that in environments where manipulation does not pay off for the parasite, it can decrease its investment in the manipulation to save resources. We experimentally infected rainbow trout Oncorhynchus mykiss with the immature larva…
Análisis molecular de la valoración del intervalo de tiempo óptimo entre la administración de acetato de triptorelina y la punción folicular en los t…
2023
Los fármacos análogos de la GnRH y la hCG han demostrado ser igualmente eficaces en la activación de la cascada de intermediarios de la maduración final ovocitaria que ocurre tras el estímulo ovulatorio. Sin embargo, su mecanismo de acción y por tanto los perfiles hormonales hallados tras el estímulo de los dos fármacos son muy diferentes. El tiempo más adecuado para programar la recolección ovocitaria tras la administración de acetato de triptorelina podría no ser 36 horas como ampliamente se ha pautado en los tratamientos de FIV con hCG. Este intervalo de tiempo es sumamente importante para obtener la mayor proporción posible de ovocitos MII porque procesos como el inicio de la luteinizac…
Geochemical characteristics of Cretaceous carbonatites from Angola
1999
Abstract The Early Cretaceous (138–130 Ma) carbonatites and associated alkaline rocks of Angola belong to the Parana-Angola-Etendeka Province and occur as ring complexes and other central-type intrusions along northeast trending tectonic lineaments, parallel to the trend of coeval Namibian alkaline complexes. Most of the Angolan carbonatite-alkaline bodies are located along the apical part of the Mocamedes Arch, a structure representing the African counterpart of the Ponta Grossa Arch in southern Brazil, where several alkaline-carbonatite complexes were also emplaced in the Early Cretaceous. Geochemical and isotopic (C, 0, Sr and Nd) characteristics determined for five carbonatitic occurren…
Who's better at spotting? A comparison between aerial photography and observer-based methods to monitor floating marine litter and marine mega-fauna.
2020
Pollution by marine litter is raising major concerns due to its potential impact on marine biodiversity and, above all, on endangered mega-fauna species, such as cetaceans and sea turtles. The density and distribution of marine litter and mega-fauna have been traditionally monitored through observer-based methods, yet the advent of new technologies has introduced aerial photography as an alternative monitoring method. However, to integrate results produced by different monitoring techniques and consider the photographic method a viable alternative, this ‘new’ methodology must be validated. This study aims to compare observations obtained from the concurrent application of observer-based and…
Virgins in the wild: mating status affects the behavior of a parasitoid foraging in the field
2008
In haplodiploid organisms, virgin females can produce offspring, albeit only sons. They may therefore face a trade-off between either: (1) searching for hosts and producing sons immediately; or (2) searching for mates and perhaps producing both sons and daughters later in life. Although this trade-off raises a theoretical interest, it has not been approached experimentally. The objective of this article is thus to document the effect of mating status on the foraging behavior of a haplodiploid parasitoid. For this, we recorded the behavior of virgin and mated female Lysiphlebus testaceipes (Hymenoptera: Braconidae) after being released, in the field, on a colony of their aphid hosts. Half of…
Evolution de la circulation oécanique profonde durant le Crétacé : apport des isotopes du néodyme
2014
The Cretaceous is depicted as the warmest period of the last 300 Ma. The oceanic circulation and location of the source zones of deep-waters are essential to understand the role of oceans in the evolution of the climate during the Cretaceous, yet they remain unclear for this period. The neodymium (Nd) isotopes are used to track oceanic circulation and exchanges between water masses, in both past and modern oceans. The Nd isotope composition (εNd) in the ocean is related to the nature of the surrounding continental landmasses. The oceanic currents transport this isotopic signature, thus every oceanic basin acquires a singular εNd. Unequivocal interpretations of the Cretaceous seawater εNd va…
Diel vertical movements of zooplankton in lake La Cruz (Cuenca, Spain)
2000
The study of diel vertical movements of zooplankton in a small meromictic karstic lake (lake La Cruz), presenting highly stratified waters, was performed using two different methodologies: (i) samples were taken along the vertical profile and were compared at different hours in a diel cycle; (ii) some plankton traps were located at different depths, covering different periods of time, to catch organisms going upwards and downwards. The main subject of this study has been the vertical movements affecting rotifers since they were dominant in the zooplankton of this lake, but we have also included the results obtained for other zooplankton groups. The results indicate an almost general movemen…
Isoëtes sabatina (IsoëtaceaeLycopodiophyta), a new aquatic species from central Italy
2013
The new species Isoetes sabatina is described and illustrated. Morphological, anatomical, and ecological characters are given. It differs from the similar I. echinospora by several characters, such as megaspore ornamentation and size, microspore size, velum extension and form, and also for its ecology. A table showing the main differential characters of the new species compared with those of the other European aquatic species is presented. So far, the species is known from a single locality (Bracciano Lake, central Italy), having a peculiar ecology and within the Mediterranean bioclimate.
Multistratigraphic records of the Lower Cretaceous (Valanginian–Cenomanian) Puez key area in N. Italy
2016
Abstract We present a stratigraphic investigation of a Hauterivian to Cenomanian hemipelagic succession from Col Puez, in the Dolomites (Southern Alps, northern Italy). A composite section of seven segments was studied with bio-, magneto-, and chemostratigraphy, which enabled detailed and robust age calibration of the Puez succession. It also revealed the paleoceanographic history and helped identify the important global climatic events of that period. The age of the Lower Cretaceous Puez Formation in the Dolomites is refined as late Hauterivian to early Cenomanian. Ammonoids provide a detailed biostratigraphic subdivision that forms the basis for analyses of the faunal distribution and the…