819 research outputs found

    Evolution along the sequence of S0 Hubble types induced by dry minor mergers. II - Bulge-disk coupling in the photometric relations through merger-induced internal secular evolution

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    Galaxy mergers are considered as questionable mechanisms for the evolution of lenticular galaxies (S0's), on the basis that even minor ones induce structural changes that are difficult to reconcile with the strong bulge-disk coupling observed in the photometric scaling relations of S0's. We check if the evolution induced onto S0's by dry intermediate and minor mergers can reproduce their photometric scaling relations, analysing the bulge-disk decompositions of the merger simulations presented in Eliche-Moral et al. (2012). The mergers induce an evolution in the photometric planes compatible with the data of S0's, even in those ones indicating a strong bulge-disk coupling. The mergers drive the formation of the observed photometric relation in some cases, whereas they induce a slight dispersion compatible with data in others. Therefore, this evolutionary mechanism tends to preserve these scaling relations. In those photometric planes where the morphological types segregate, the mergers always induce evolution towards the region populated by S0's. The structural coupling of the bulge and the disk is preserved or reinforced because the mergers trigger internal secular processes in the primary disk that induce significant bulge growth, even although these models do not induce bars. Intermediate and minor mergers can thus be considered as plausible mechanisms for the evolution of S0's attending to their photometric scaling relations, as they can preserve and even strengthen any pre-existing structural bulge-disk coupling, triggering significant internal secular evolution (even in the absence of bars or dissipational effects). This means that it may be difficult to isolate the effects of pure internal secular evolution from those of the merger-driven one in present-day early-type disks (abridged).Comment: Accepted for publication in Astronomy & Astrophysics, 13 pages, 8 figures. Definitive version after proofs. Added references and corrected typo

    Higher longevity and fecundity of Chrysoperla carnea, a predator of olive pests, on some native flowering Mediterranean plants

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    International audienceAbstractBiological control is the use of natural enemies, such as predators, of crop pests. For instance, Chrysoperla carnea (Stephens) is a major predator of olive grove pests. To favor the abundance of C. carnea, flowering plants should provide them with carbohydrates. However, there is a lack of knowledge on the biology of flowering plants that grow in olive groves. Therefore, we studied in the laboratory 11 native Mediterranean plants commonly found in traditional olive orchards as food sources for C. carnea adults. Male and female longevity and female lifetime fecundity were measured on a daily base. Plant nectar and pollen were quantified by high-performance anion-exchange chromatography analysis (HPAEC-PAD). Our results show that the longevity of C. carnea females was higher, of 17 days, when fed with Conopodium majus flowers, and of 14 days when fed with Lonicera hispanica flowers. Female fecundity was higher for C. carnea individuals fed with C. majus, giving 71 eggs, and with Foeniculum vulgare, giving 66 eggs, than for C. carnea individuals fed with L. hispanica (19 eggs) and Asparagus acutifolius (4 eggs). These findings are explained by the higher concentration of trehalose in plant nectar and pollen. To our knowledge, this is the first study evaluating the sugar profile and content of Mediterranean flower plants as food resource of C. carnea adults indicating that trehalose content in pollen and nectar has a key role in C. carnea fecundity and longevity

    Highly polymorphic microsatellite markers for the Mediterranean endemic fan mussel Pinna nobilis

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    Pinna nobilis is an endemic bivalve of the Mediterranean Sea whose populations have decreased in the last decades due to human pressure; as a consequence, it was declared a protected species in 1992. Despite its conservation status, few genetic studies using mitochondrial markers have been published. We report on the isolation and development of 10 microsatellite loci for the fan mussel, Pinna nobilis. All loci (2 di-nucleotide, 5 tri-nucleotide, 2 tetra-nucleotide and 1 penta-nucleotide) are characterized by high levels of polymorphism in 76 individuals tested from two populations in the Balearic Islands (Spain, Western Mediterranean Sea). The number of alleles ranged from 4 to 24 and expected heterozygosity ranged from 0.4269 to 0.9400. These microsatellites could be very useful for the assessment of the genetic diversity and connectivity patterns of P. nobilis and the establishment of new conservation strategies

    Comprensión léxica en estudiantes sordos de educación primaria. Detección de necesidades para el enriquecimiento lingüístico

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    Se ha evaluado a 45 estudiantes sordos de educación primaria (8 y 12 años). Presentan sordera bilateral prelocutiva severa o profunda, el 44% emplean audífonos y el 56% implante coclear. Todos están escolarizados en régimen de inclusión, son hijos de padres oyentes y emplean la lengua oral española. La evaluación se ha realizado con el Test de Vocabulario en Imágenes Peabody, obteniéndose las puntuaciones percentil y CI. Estos datos nos han permitido agrupar a los participantes en función del nivel de comprensión léxica: G1 los que obtienen puntuaciones que se encuentran dos desviaciones típicas por debajo de la media y G2 los que alcanzan puntuaciones que los sitúan a menos de dos desviaciones típicas. Para extraer información del tipo de dificultades en la comprensión léxica, se ha desarrollado un procedimiento de análisis “ad hoc”: 1.- De las hojas de respuesta de todos los participantes se han extraído todas las palabras en las que se registró error y, a partir de un análisis de frecuencia, se han seleccionado las palabras en las que más participantes cometían errores. En total 25 palabras que incluyen sustantivos, verbos y adjetivos. 2.- Se ha analizado estadísticamente de entre esas palabras de mayor frecuencia de error en cuáles había diferencias significativas entre los grupos G1 y G2. 3.- Se ha realizado un análisis léxico-semántico y morfológico de aquellas palabras que resultaron representativas de las dificultades de comprensión del G1. El 60% de los participantes obtuvieron puntuaciones que los situaban dos desviaciones típicas por debajo de la media. El tipo de léxico que no comprendía este grupo se concentra principalmente en los bloques del test de 6-7 y 8-9 años. El vocabulario identificado orienta la intervención hacia la comprensión de relaciones semánticas: taxonomía y sinonimia. También se concluye la necesidad de ampliación del conocimiento de los rasgos semánticos de las palabras, así como del significado de sus prefijos y sufijos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Iterative Learning Control of Single Point Incremental Sheet Forming Process using Digital Image Correlation

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    Single Point Incremental Sheet Forming (SPIF) is a versatile forming process that has gained significant traction over the past few decades. Its increased formability, quick part adaption, and reduced set-up costs make it an economical choice for small batch and rapid prototype forming applications when compared to traditional stamping processes. However, a common problem with the SPIF process is its tendency to produce high geometric error due to the lack of supporting dies and molds. While geometric error has been a primary focus of recent research, it is still significantly larger for SPIF than traditional forming processes. In this paper, the convergence behavior and the ability to reduce geometric error using a simple Iterative Learning Control (ILC) algorithm is studied with two different forming methods. For both methods a tool path for the desired reference geometry is generated and a part is formed. A Digital Image Correlation (DIC) system takes a measurement and the geometric error along the tool path is calculated. The ILC algorithm then uses the geometric error to alter the tool path for the next forming iteration. The first method, the Single Sheet Forming (SSF) method, performs each iteration on the same sheet. The second method, the Multi Sheet Forming (MSF) method, performs each iteration on a newly replaced sheet. Multiple experiments proved the capability of each method at reducing geometric error. It was concluded that using the MSF method allows for negative corrections to the forming part and, therefore, leads to better final part accuracy. However, this method is less cost effective and more time consuming than using the standard SSF methodology. In addition, it was found that in order to effectively correct a part with an ILC algorithm, steps must be taken to increase the controllability of the part geometry

    Acute exposure to sublethal doses of neonicotinoid insecticides increases heat tolerance in honey bees

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    The European honey bee, Apis mellifera L., is the single most valuable managed pollinator in the world. Poor colony health or unusually high colony losses of managed honey bees result from a myriad of stressors, which are more harmful in combination. Climate change is expected to accentuate the effects of these stressors, but the physiological and behavioral responses of honey bees to elevated temperatures while under simultaneous influence of one or more stressors remain largely unknown. Here we test the hypothesis that exposure to acute, sublethal doses of neonicotinoid insecticides reduce thermal tolerance in honey bees. We administered to bees oral doses of imidacloprid and acetamiprid at 1/5, 1/20, and 1/100 of LD50 and measured their heat tolerance 4 h post-feeding, using both dynamic and static protocols. Contrary to our expectations, acute exposure to sublethal doses of both insecticides resulted in higher thermal tolerance and greater survival rates of bees. Bees that ingested the higher doses of insecticides displayed a critical thermal maximum from 2 ˚C to 5 ˚C greater than that of the control group, and 67%–87% reduction in mortality. Our study suggests a resilience of honey bees to high temperatures when other stressors are present, which is consistent with studies in other insects. We discuss the implications of these results and hypothesize that this compensatory effect is likely due to induction of heat shock proteins by the insecticides, which provides temporary protection from elevated temperatures

    Analysis of Geometric Accuracy and Thickness Reduction in Multistage Incremental Sheet Forming using Digital Image Correlation

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    Incremental Sheet Forming (ISF) is a freeform manufacturing method whereby a 3D geometry is created by progressively deforming a metal sheet with a single point tool following a defined trajectory. The thickness distribution of a formed part is a major consideration of the process and is believed to be improved by forming the geometry in multiple stages. This paper describes a series of experiments in which truncated cone geometries were formed using two multistage methods and compared to the same geometry formed using the traditional single stage method. The geometric accuracy and thickness distributions, including 3D thickness distribution plots, of each are examined using digital image correlation (DIC). The data collected indicate that multistage forming, compared to single stage forming, has a significant effect on the geometric accuracy of the processed sheets. Moreover, the results of the experiments conducted in this paper show that sheets processed with multistage forming do not have a uniform sheet thickness reduction, rather they have a parabolic-like thickness distribution in the processed region

    The Water Vapor Abundance in Orion KL Outflows

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    We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, towards Orion KL. Observations were performed with the Long Wavelength Spectrometer Fabry-Perot (LWS/FP; R~6800-9700) on board the Infrared Space Observatory (ISO) between ~43 and ~197 um. The water line profiles evolve from P-Cygni type profiles (even for the H2O18 lines) to pure emission at wavelengths above ~100 um. We find that most of the water emission/absorption arises from an extended flow of gas expanding at 25+-5 kms^-1. Non-local radiative transfer models show that much of the water excitation and line profile formation is driven by the dust continuum emission. The derived beam averaged water abundance is 2-3x10^-5. The inferred gas temperature Tk=80-100 K suggests that: (i) water could have been formed in the "plateau" by gas phase neutral-neutral reactions with activation barriers if the gas was previously heated (e.g. by shocks) to >500 K and/or (ii) H2O formation in the outflow is dominated by in-situ evaporation of grain water-ice mantles and/or (iii) H2O was formed in the innermost and warmer regions (e.g. the hot core) and was swept up in ~1000 yr, the dynamical timescale of the outflow.Comment: Accepted for publication in ApJ letters [2006 August 7] (5 pages 2, figures, not edited
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