Nesting behaviour influences species-specific gas exchange across avian eggshells

Carefully controlled gas exchange across the eggshell is essential for the development of the avian embryo. Water vapour conductance (GH2O) across the shell, typically measured as mass loss during incubation, has been demonstrated to optimally ensure the healthy development of the embryo while avoiding desiccation. Accordingly, eggs exposed to sub-optimal gas exchange have reduced hatching success. We tested the association between eggshell GH2O and putative life-history correlates of adult birds, ecological nest parameters and physical characteristics of the egg itself to investigate how variation in GH2O has evolved to maintain optimal water loss across a diverse set of nest environments. We measured gas exchange through eggshell fragments in 151 British breeding bird species and fitted phylogenetically controlled, general linear models to test the relationship between GH2O and potential predictor parameters of each species. Of our 17 life-history traits, only two were retained in the final model: wet-incubating parent and nest type. Eggs of species where the parent habitually returned to the nest with wet plumage had significantly higher GH2O than those of parents that returned to the nest with dry plumage. Eggs of species nesting in ground burrows, cliffs and arboreal cups had significantly higher GH2O than those of species nesting on the ground in open nests or cups, in tree cavities and in shallow arboreal nests. Phylogenetic signal (measured as Pagel's λ) was intermediate in magnitude, suggesting that differences observed in the GH2O are dependent upon a combination of shared ancestry and species-specific life history and ecological traits. Although these data are correlational by nature, they are consistent with the hypothesis that parents constrained to return to the nest with wet plumage will increase the humidity of the nest environment, and the eggs of these species have evolved a higher GH2O to overcome this constraint and still achieve optimal water loss during incubation. We also suggest that eggs laid in cup nests and burrows may require a higher GH2O to overcome the increased humidity as a result from the confined nest microclimate lacking air movements through the nest. Taken together, these comparative data imply that species-specific levels of gas exchange across avian eggshells are variable and evolve in response to ecological and physical variation resulting from parental and nesting behaviours

Fraseología y estereotipos en español. ¿Una relación bidireccional?

La mayoría de los trabajos que, en los últimos años, abordan el estudio de la fraseología desde los principios de la lingüística cognitiva coinciden en considerar que buena parte de las unidades fraseológicas son de naturaleza conceptual y que, de algún modo, conservan la manera en que una determinada cultura entiende el mundo. El presente trabajo se propone estudiar el caso opuesto, es decir, si una persona que usa una unidad fraseológica (o que al menos la conoce) tiende a compartir, de manera inconsciente, los estereotipos y actitudes que se hallan implícitos en dicho fraseologismo. Con la intención de validar o refutar esta hipótesis, en este artículo se analizan los resultados de 50 encuestas en las que se relacionan 18 unidades fraseológicas españolas -referidas a naciones y grupos étnicos- con los estereotipos que se "ocultan" en ellas. En el apartado de conclusiones se apunta la posibilidad de que, efectivamente, existe una relación bidireccional entre unidades fraseológicas y estereotipos.The most recent works on phraseology based on the cognitive approach assume that most idioms are conceptual in nature and that they often preserve the way a given cultural community understands and views the world. This paper aims to study the opposite case, i.e., whether a person using the idioms or who is at least familiar with them tends to unconsciously share the stereotypes and attitudes underlying those idioms. In order to prove or refute this hypothesis, a survey questionnaire that relates 18 Spanish idioms - regarding nations and ethnic groups - and the stereotypes "hidden" in these idioms was designed. In this paper the results obtained from 50 survey cases are presented and commented on in detail, as a result of which the existence of a bidirectional relation between idioms and stereotypes is proposed

Particle swarm optimization-based stator resistance observer for speed sensorless induction motor drive

This paper presents a different technique for the online stator resistance estimation using a particle swarm optimization (PSO) based algorithm for rotor flux oriented control schemes of induction motor drives without a rotor speed sensor. First, a conventional proportional-integral controller-based stator resistance estimation technique is used for a speed sensorless control scheme with two different model reference adaptive system (MRAS) concepts. Finally, a novel method for the stator resistance estimation based on the PSO algorithm is presented for the two MRAS-type observers. Simulation results in the Matlab/Simulink environment show good adaptability of the proposed estimation model while the stator resistance is varied to 200% of the nominal value. The results also confirm more accurate stator resistance and rotor speed estimation in comparison with the conventional technique

Regularization strategy for the layered inversion of airborne TEM data: application to VTEM data acquired over the basin of Franceville (Gabon)

Airborne transient electromagnetic (TEM) is a cost-effective method to image the distribution of electrical conductivity in the ground. We consider layered earth inversion to interpret large data sets of hundreds of kilometre. Different strategies can be used to solve this inverse problem. This consists in managing the a priori information to avoid the mathematical instability and provide the most plausible model of conductivity in depth. In order to obtain fast and realistic inversion program, we tested three kinds of regularization: two are based on standard Tikhonov procedure which consist in minimizing not only the data misfit function but a balanced optimization function with additional terms constraining the lateral and the vertical smoothness of the conductivity; another kind of regularization is based on reducing the condition number of the kernel by changing the layout of layers before minimizing the data misfit function. Finally, in order to get a more realistic distribution of conductivity, notably by removing negative conductivity values, we suggest an additional recursive filter based upon the inversion of the logarithm of the conductivity. All these methods are tested on synthetic and real data sets. Synthetic data have been calculated by 2.5D modelling; they are used to demonstrate that these methods provide equivalent quality in terms of data misfit and accuracy of the resulting image; the limit essentially comes on special targets with sharp 2D geometries. The real data case is from Helicopter-borne TEM data acquired in the basin of Franceville (Gabon) where borehole conductivity loggings are used to show the good accuracy of the inverted models in most areas, and some biased depths in areas where strong lateral changes may occur

Radiation-Tolerant Custom Made Low Voltage Power Supply System for ATLAS/TileCal Detector

This paper describes custom made Low Voltage Power Supply (LVPS) system developed for the ATLAS – TileCal detector of the LHC (The Large Hadron Collider) particle accelerator at CERN, Geneva. The system is based on the use of only COTS (Commercial of The Shelf) components, is qualified to be radiation tolerant up to 40krad, and can operate in external DC magnetic field above 0.02 Tesla. The LVPS design described in this paper has been developed and produced for the ATLAS TileCal detector during the years 2001 – 2007