92 research outputs found

    Resource Competition Triggers the Co-Evolution of Long Tongues and Deep Corolla Tubes

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    Background: It is normally thought that deep corolla tubes evolve when a plant’s successful reproduction is contingent on having a corolla tube longer than the tongue of the flower’s pollinators, and that pollinators evolve ever-longer tongues because individuals with longer tongues can obtain more nectar from flowers. A recent model shows that, in the presence of pollinators with long and short tongues that experience resource competition, coexisting plant species can diverge in corolla-tube depth, because this increases the proportion of pollen grains that lands on co-specific flowers. Methodology/Principal Findings: We have extended the model to study whether resource competition can trigger the coevolution of tongue length and corolla-tube depth. Starting with two plant and two pollinator species, all of them having the same distribution of tongue length or corolla-tube depth, we show that variability in corolla-tube depth leads to divergence in tongue length, provided that increasing tongue length is not equally costly for both species. Once the two pollinator species differ in tongue length, divergence in corolla-tube depth between the two plant species ensues. Conclusions/Significance: Co-evolution between tongue length and corolla-tube depth is a robust outcome of the model, obtained for a wide range of parameter values, but it requires that tongue elongation is substantially easier for one pollinator species than for the other, that pollinators follow a near-optimal foraging strategy, that pollinators experienc

    The use of wet-laid techniques to obtain flax nonwovens with different thermoplastic binding fibers for technical insulation applications

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    [EN] In this work, the wet-laid technique has been used to obtain flax nonwovens thermally bonded with different contents of polyvinyl alcohol (PVA) and bicomponent polyamide 6/copolyamide (PA6/CoPA) fibers in the 10-30 wt.% range. Scanning electron microscopy has been used to evaluate the formation of interlock points through melted polymer and flax fibers. Volume porosity has been estimated through determination of thickness and surface mass. Tensile strength and elongation at break have been determined on longitudinal (preferential) and transversal directions to evaluate anisotropy. The sound absorption properties of stacked sheets of flax: PVA and flax: PA6/CoPA nonwovens have been evaluated. In addition, the thermal insulating properties of individual nonwovens have been obtained. Mechanical characterization shows slight anisotropy. The absorption coefficient is interesting in the medium frequencies range, and relatively low thermal conductivity and thermal resistance values are obtained with these nonwovens (in the 0.020-0.025Wm(-1) K-1 range for flax: PVA nonwovens and in the 0.09-0.10Wm(-1) K-1 range for flax: PA6/CoPA nonwovens). By taking into account these features, these nonwoven substrates could find interesting applications as sound absorbers and/or thermal insulation materials in technical applications.This work is part of the project IPT-310000-2010-037, "ECOTEXCOMP: Research and development of textile structures useful as reinforcement of composite materials with marked ecological character", and was supported by the "Ministerio de Ciencia e Innovacion", with a grant of (sic)189,540.20, within the Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica 2008-2011 and funded by the European Union through FEDER funds, Technology Fund 2007-2013 and Operational Programme on R + D + i for and on behalf of the companies. The project is also known as "WET-TEX: Implementacion de la tecnologia wet-laid en el desarrollo de nuevos textiles medico-sanitario" with expedient number IMIDIC/2010/137 (total grant of (sic)284,400) and the project "WET-TEX II: Implementacion de la tecnologia wet-laid en la investigacion y desarrollo de paneles para aplicaciones tecnicas a partir de residuos procedentes de la industria textil" with expedient number IMDEEA/2011/167 (total grant of (sic)255,000) funded by IMPIVA and cofunded (80%) by the European Union through FEDER funds, Valencian Community Operational 2007-2012.Fages, E.; Cano, MA.; Gironés, S.; Boronat Vitoria, T.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2013). The use of wet-laid techniques to obtain flax nonwovens with different thermoplastic binding fibers for technical insulation applications. Textile Research Journal. 83(4):426-437. https://doi.org/10.1177/0040517512454183S42643783

    Estudio de la eficacia de una vacuna frente a la Lactococosis de la trucha arco iris (Oncorhynchus mykiss) a diferentes temperaturas.

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    Lactococcus garvieae es el agente etiológico de la Lactococosis, considerada actualmente comouna enfermedad emergente responsable de graves pérdidas económicas tanto en acuiculturacontinental como marina cuando la temperatura del agua supera los 16ºC. En la actualidad, lavacunación con vacunas inactivadas se ha establecido como el método más eficaz para controlarel proceso.En el presente trabajo hemos evaluado la eficacia de una vacuna comercial (Icthiovac-Lg) frentea una infección experimental con L. garvieae en trucha arco iris (Oncorhynchus mykiss) habiendovacunado los peces a diferentes temperaturas del agua.Dos grupos de 50 truchas de 30-35 g de peso fueron vacunadas a temperaturas de 8 y 15ºCrespectivamente. Fueron mantenidas en estas condiciones junto con otras 50 truchas más sinvacunar en cada grupo durante 30 días, momento en el cual se procedió a realizar una infecciónexperimental vía intraperitoneal con una cepa patógena de L. garvieae. Los peces se mantuvieronen observación durante 21 días más. Al final del estudio se obtuvo un valor de RPS (PorcentajeRelativo de Supervivencia) para el grupo vacunado a temperatura alta de 96% mientras quepara el grupo vacunado a 8ºC fue de 83%

    The Physics of the Accelerating Universe Survey: narrow-band image photometry

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    PAUCam is an innovative optical narrow-band imager mounted at the William Herschel Telescope built for the Physics of the Accelerating Universe Survey (PAUS). Its set of 40 filters results in images that are complex to calibrate, with specific instrumental signatures that cannot be processed with traditional data reduction techniques. In this paper, we present two pipelines developed by the PAUS data management team with the objective of producing science-ready catalogues from the uncalibrated raw images. The NIGHTLY pipeline takes care of entire image processing, with bespoke algorithms for photometric calibration and scatter-light correction. The Multi-Epoch and Multi-Band Analysis pipeline performs forced photometry over a reference catalogue to optimize the photometric redshift (photo-z) performance. We verify against spectroscopic observations that the current approach delivers an inter-band photometric calibration of 0.8 per cent across the 40 narrow-band set. The large volume of data produced every night and the rapid survey strategy feedback constraints require operating both pipelines in the Port d’Informació Cientifica data centre with intense parallelization. While alternative algorithms for further improvements in photo-z performance are under investigation, the image calibration and photometry presented in this work already enable state-of-the-art photo-z down to iAB = 23.0

    The PAU Survey: Narrow-band image photometry

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    PAUCam is an innovative optical narrow-band imager mounted at the William Herschel Telescope built for the Physics of the Accelerating Universe Survey (PAUS). Its set of 40 filters results in images that are complex to calibrate, with specific instrumental signatures that cannot be processed with traditional data reduction techniques. In this paper we present two pipelines developed by the PAUS data management team with the objective of producing science-ready catalogues from the uncalibrated raw images. The Nightly pipeline takes care of all image processing, with bespoke algorithms for photometric calibration and scatter-light correction. The Multi-Epoch and Multi-Band Analysis (MEMBA) pipeline performs forced photometry over a reference catalogue to optimize the photometric redshift performance. We verify against spectroscopic observations that the current approach delivers an inter-band photometric calibration of 0.8% across the 40 narrow-band set. The large volume of data produced every night and the rapid survey strategy feedback constraints require operating both pipelines in the Port d'Informaci\'o Cientifica data centre with intense parallelization. While alternative algorithms for further improvements in photo-z performance are under investigation, the image calibration and photometry presented in this work already enable state-of-the-art photometric redshifts down to iAB=23.0.Comment: 32 pages, 26 figures, MNRAS in pres

    El modelo integrador y de innovación docente del Grado en Veterinaria de Zaragoza: integración en équidos

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    Desde hace cuatro años se ha comenzado a impartir en la Universidad de Zaragoza el nuevo Grado en Veterinaria, de 300 créditos ECTS distribuidos en 5 cursos. En el diseño de este nuevo Plan de Estudios se ha tratado de dotar a la Titulación de un enfoque basado, fundamentalmente, en las competencias que la profesión exige y la sociedad necesita de un t itulado (graduado) en veterinaria. Tras una formación inicial básica el alumno llega al CUARTO CURSO del grado, en el que las materias se han organizado en asignaturas siguiendo una estructura totalmente novedosa para los estudios de veterinaria en España. Como consecuencia de esta nueva estructura desaparecen como tales muchas de las asignaturas tradicionales que han estado presentes como asignaturas propias (con denominaciones idénticas o similares) en la práctica totalidad de los planes de estudio de veterinaria españoles desde la década de los 70 del siglo pasado. Al cursar estas asignaturas, los alumnos de esos planes, estudiábamos las particularidades de las diferentes especies animales de interés veterinario desde el enfoque, inevitablemente compartimentalizado, de esas asignaturas

    You Mate, I Mate: Macaque Females Synchronize Sex not Cycles

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    Extended female sexuality in species living in multimale-multifemale groups appears to enhance benefits from multiple males. Mating with many males, however, requires a low female monopolizability, which is affected by the spatiotemporal distribution of receptive females. Ovarian cycle synchrony potentially promotes overlapping receptivity if fertile and receptive periods are tightly linked. In primates, however, mating is often decoupled from hormonal control, hence reducing the need for synchronizing ovarian events. Here, we test the alternative hypothesis that females behaviorally coordinate their receptivity while simultaneously investigating ovarian cycle synchrony in wild, seasonal Assamese macaques (Macaca assamensis), a promiscuous species with extremely extended female sexuality. Using fecal hormone analysis to assess ovarian activity we show that fertile phases are randomly distributed, and that dyadic spatial proximity does not affect their distribution. We present evidence for mating synchrony, i.e., the occurrence of the females' receptivity was significantly associated with the proportion of other females mating on a given day. Our results suggest social facilitation of mating synchrony, which explains (i) the high number of simultaneously receptive females, and (ii) the low male mating skew in this species. Active mating synchronization may serve to enhance the benefits of extended female sexuality, and may proximately explain its patterning and maintenance

    Sexual Cannibalism: High Incidence in a Natural Population with Benefits to Females

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    10 pages, 3 figures.[Background] Sexual cannibalism may be a form of extreme sexual conflict in which females benefit more from feeding on males than mating with them, and males avoid aggressive, cannibalistic females in order to increase net fitness. A thorough understanding of the adaptive significance of sexual cannibalism is hindered by our ignorance of its prevalence in nature. Furthermore, there are serious doubts about the food value of males, probably because most studies that attempt to document benefits of sexual cannibalism to the female have been conducted in the laboratory with non-natural alternative prey. Thus, to understand more fully the ecology and evolution of sexual cannibalism, field experiments are needed to document the prevalence of sexual cannibalism and its benefits to females.[Methodology/Principal Findings] We conducted field experiments with the Mediterranean tarantula (Lycosa tarantula), a burrowing wolf spider, to address these issues. At natural rates of encounter with males, approximately a third of L. tarantula females cannibalized the male. The rate of sexual cannibalism increased with male availability, and females were more likely to kill and consume an approaching male if they had previously mated with another male. We show that females benefit from feeding on a male by breeding earlier, producing 30% more offspring per egg sac, and producing progeny of higher body condition. Offspring of sexually cannibalistic females dispersed earlier and were larger later in the season than spiderlings of non-cannibalistic females.[Conclusions/Significance] In nature a substantial fraction of female L. tarantula kill and consume approaching males instead of mating with them. This behaviour is more likely to occur if the female has mated previously. Cannibalistic females have higher rates of reproduction, and produce higher-quality offspring, than non-cannibalistic females. Our findings further suggest that female L. tarantula are nutrient-limited in nature and that males are high-quality prey. The results of these field experiments support the hypothesis that sexual cannibalism is adaptive to females.This paper has been written under a Ramón y Cajal research contract from the Spanish Ministry of Science and Technology (MCYT) to JML and an I3P-BPD2004-CSIC scholarship to RRB. This work has been funded by MEC grants CGL2004-03153 and CGL2007-60520 to JML, MARG, RRB, CFM and DHW.Peer reviewe
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