Brood desertion by female shorebirds: A test of the differential parental capacity hypothesis on Kentish plovers

The aim of this study was to examine whether the energetic costs of reproduction explain offspring desertion by female shorebirds, as is suggested by the differential parental capacity hypothesis. A prediction of the hypothesis is that, in species with biparental incubation in which females desert from brood care after hatching, the body condition of females should decline after laying to a point at which their body reserves are too low for continuing parental care. We tested this prediction on Kentish plovers (Charadrius alexandrinus) in which both sexes incubate but the females desert from brood care before the chicks fledge. We found no changes in either the body masses or body compositions of both individual male and female plovers from early incubation and throughout early chick rearing. Furthermore, the timing of brood desertion by females was not affected by their body condition. Neither did we find gender differences in the energetic costs of incubation. There were no differences in the timing of brood desertion between experimental and control females in an experiment in which we lengthened or shortened the duration of incubation by one week. These results indicate that energetic costs do not explain offspring desertion by female Kentish plovers and that the needs of chicks for parental care rather than cumulative investment by females is what determines the timing of brood desertion.Peer Reviewe

Modelo de indicadores para la didáctica entendida como proyecto en la educación superior, o acerca de su interpretacion de acuerdo a la teoria de los signos de Charles S. Peirce

RESUMEN: Los indicadores deben cumplir el doble fin de servir al Estado como instrumento de regulación del sector de la educación superior y a las instituciones para orientar sus procesos de mejoramiento y rendir cuentas a la sociedad sobre lo que ellas hacen con los recursos públicos. En este sentido los indicadores propuestos por el C.N.A. al no orientarse bajo los postulados de la didáctica, corren el riesgo de servir, aparentemente, para la primera función sin orientar la segunda. Esto pone en evidencia la trascendencia de los indicadores que se utilicen al poner de presente que ellos sirven para apoyar diversas decisiones sobre política en materia de educación superior

Sex-related seasonal differences in the foraging strategy of the Kentish Plover

In species of birds with biparental care, each sex may have its own energy requirements and/or schedule for feeding, possibly leading the sexes to differ in foraging strategy. In estuaries, shorebirds such as the Kentish Plover (Charadrius alexandrinus alexandrinus) may forage on intertidal mudflats and in adjacent su- pratidal habitats during winter as well as during the breeding season. In this study, we analyzed the diet, use of foraging habitat, food-intake rate (biomass ingested per unit time), and time allocated to foraging by male and female Kentish Plovers at both seasons in an estuary near Cádiz, Spain, where intertidal mudflats and adjacent salt works are the main habitats for foraging. The plovers’ main prey was the ragworm (Nereis diversicolor), an intertidal polychaete that supplied more than 80% of the biomass consumed at each season. During the breeding season, both sexes increased their intake rate and decreased their daylight foraging time. By increasing the diurnal intake rate during the breeding season, the birds minimized their time spent foraging on the intertidal mudflats, allowing them to maximize the time for activities associated with breeding in the adjacent salt works. Therefore, the plovers solved the conflict between foraging on the mudflats and breeding in the salt works by shortening the foraging time on the mudflats, minimizing time away from the nesting areas. The sexes differed in the daylight time allocated to foraging, with females spending 2 hr less on foraging and concentrating their feeding activity into the central hours of low tideEn especies de aves con cuidado biparental, cada sexo puede tener sus propios requerimientos de energía y/o esquema de tiempo para la alimentación, lo cual podría conducir a diferencias en las estrategias de alimentación entre ambos sexos. En los estuarios, las especies de playeros como Charadrius alexandrinus pueden forrajear en fangos intermareales y en hábitats supramareales adyacentes tanto durante el invierno así como du- rante la época reproductiva. Aquí, analizamos la dieta, el uso de hábitat de forrajeo, la tasa de ingestión (biomasa ingerida por unidad de tiempo) y el tiempo dedicado al forrajeo por el macho y la hembra de C. alexandrinus du- rante ambas temporadas en una zona estuarina donde los fangos intermareales y las salinas adyacentes son las principales áreas de alimentación. La principal presa para C. alexandrinus fue un poliqueto (Nereis diversicolor), una presa intermareal que suplió más del 80% de la biomasa consumida en cada estación. Ambos sexos incremen- taron sus tasas de alimentación durante la época reproductiva, y disminuyeron sus tiempos diurnos de forrajeo. Por el incremento de la tasa de ingestión durante la época reproductiva, las aves minimizaron el tiempo que pasaron en los fangos intermareales, lo que les permitió maximizar el tiempo dedicado a las actividades de reproducción en las salinas adyacentes. Por lo tanto, el conflicto entre alimentarse en los fangos versus el desarrollo de las ac- tividades de reproducción (en las salinas), fue resuelto acortando el tiempo en los fangos, minimizando el tiempo fuera de las zonas de nidada. Hubo diferencias relacionadas con el sexo en el tiempo diurno dedicado al forrajeo: las hembras dedicaron dos horas menos a la alimentación y concentraron su actividad de alimentación en las horas centrales de la marea baja

A trade-off between overheating and camouflage on shorebird eggshell colouration

In ground-nesting birds egg colour and appearance may have evolved due to opposite selection pressures. Pigmentation and spottiness make the eggs darker and have been suggested to improve camouflage. However darker and more spotted eggs may reach higher temperatures when not attended by adults and receiving direct sunlight, which may be lethal for embryos. Some authors suggested that this trade-off may not exist because eggshell pigments mainly reflect in the infrared region of the solar spectrum, but have not considered that wavelengths in the visible part of the spectrum may also contribute to overheating. To test the occurrence of a trade-off between camouflage and overheating of eggs, we took digital images to analyse colour and camouflage in 93 nests of four shorebird species (two stilts and two plovers) in two regions (tropical and mediterranean sites). We predicted that these species (closely related) may have evolved different eggshell designs depending on solar radiation, which is supposed to be stronger in the Tropics. To record egg temperatures, we placed Japanese quail eggs in natural nests of shorebirds, and registered temperatures using a datalogger. We found that darker and more spotted eggs reached higher temperatures than lighter ones, and that after controlling for environmental temperatures, eggs overheated more in the Tropics, likely because of a more intense solar radiation. We also found that tropical shorebirds’ eggshells have darker spots and lighter backgrounds. Overall, darker eggs were better camouflaged. Taken together, our results show that the benefits of increasing pigmentation of eggshell backgrounds and spottiness for a better camouflage are counteracted by the increased risks of overheating when eggs remain exposed to direct solar radiation.Peer reviewe

Tolerancia a la salinidad de Passiflora tarminiana Coppens & Barney

1 recurso en línea (páginas 11-19).Passiflora tarminiana es una glicofita trepadora, nativa de la región andina que tiene tolerancia a la salinidad y estrés hídrico moderado. El objetivo de este estudio fue evaluar la capacidad para la excreción de sodio como una posible estrategia de esta especie para la tolerancia a la salinidad y a la sequía. La excreción de sal y las concentraciones de iones excretados se examinaron en plantas cultivadas durante siete meses bajo varios niveles de salinidad [(NaCl) 2,5; 4,0 y 5,5 dS m-1 (25, 40 y 55 mM)] y de estrés hídrico moderado (33 y 100% de humedad en el sustrato). El experimento fue llevado a cabo en un diseño completamente al azar con un arreglo de parcelas subdivididas, donde la parcela constituye el porcentaje de saturación de agua (33 y 100%), la subparcela los niveles de saturación de sal (CE: 2,5; 4,0 y 5,5 dS m-1), con cinco repeticiones, y la unidad experimental compuesta por una planta. Se evaluaron los cristales de sal y las estructuras de la epidermis foliar. Las sales fueron excretadas en la superficie adaxial de la hoja, posiblemente debido a las glándulas secretoras de sal especializadas. Se observaron otras estructuras como tricomas y papilas, que se cree que también están implicadas en la tolerancia a la salinidad en P. tarminiana.moderate water stress. The aim of this study was to evaluate its capacity for sodium excretion as a possible strategy for salinity tolerance and the drought. Salt excretion and excreted ion concentrations were evaluated in plants grown for seven months under various levels of salinity [(NaCl) 2.5, 4.0, and 5.5 dS m-1 (25, 40 and 55 mM)] and moderate water stress (33 and 100% moisture in the substrate). The experiment design was completely randomized in a split-plot array, where the plot was determined by the percentage of water saturation (33% and 100%). The ubplot had saturation levels of salinity (EC: 2.5, 4.0, and 5.5 dS m-1), with five replicates. The experiment unit consisted of one plant. Salt crystals and structures of the leaf epidermis were evaluated. Salts were excreted in the adaxial leaf surface, possibly because of specialized salt secreting glands. Other structures, such as trichomes and papillae, were also observed, which are believed to also be involved in the salt tolerance of P. tarminiana.Bibliografía: páginas 18-1

Survival outcomes in laryngeal chondrosarcoma: a systematic review

[Abstract] Laryngeal chondrosarcomas (LCS) are rare lesions that behave as locally aggressive tumours, producing symptoms such as dysphonia, dyspnoea, dysphagia and hoarseness. Different approaches for the treatment of LCS have been described in the literature. The main purpose of this investigation was to find all cases of LCS published to date and analyse management data and survival outcomes. In December 2020, a systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Provider Enrollment, Chain, and Ownership System (PECOS) method including articles published up to this date on different aspects of LCS. The search included the terms larynx, laryngeal, chondrosarcoma. A total of 148 articles were included in this systematic review describing 381 cases of LCS. Dyspnoea was the most reported symptom followed by hoarseness and neck mass sensation. Cricoid cartilage was the most usual location. Survival rate was influenced by both surgical technique (log-rank = 11.7; p = 0.008) and the degree of tumour histologic differentiation (log-rank = 18.3; p = 0.003)

Quail eggs in artificial nests change their coloration when exposed to ambient conditions: implication for studies on nest predation

Quail eggs have been widely used in field experiments, mainly to study factors associated with the risk of nest predation. Some shortcomings of using quail eggs in this type of study have been previously addressed (e.g., these eggs might be too big for some predators of eggs of small birds). Here, we show experimental evidence of another shortcoming of the use of these eggs in field experiments. Quail eggs exposed to sunlight rapidly faded in colour after three days, both in the visible and UV spectra, and this change was related to the amount of solar radiation received. This caused changes in the camouflage of the eggs, which may be perceived by predators with different visual systems (dichromatic, trichromatic, and tetrachromatic (for both violet- and UV-sensitive species)). Therefore, the results of field studies of nest predation using quail eggs might be questioned in those cases in which the camouflage has been altered due to the rapid changes in coloration, as this can affect the resulting predation rates. We recommend that researchers planning to use quail eggs should perform a prospective assessment of changes in coloration of eggs exposed to environmental conditions in the nest sites used by the target species.This study was funded by grant CGL2017-83518-P from Ministerio de Economia, Industria y Competitividad, Spain, with EU-ERDF financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

A low dose of angiotensin II increases inotropism through activation of reverse Na+/Ca2+ exchange by endothelin release

Objective: This work was aimed to prove that release/formation of endogenous endothelin acting in an autocrine/paracrine fashion contributes to the increase in contractility promoted by a low dose of angiotensin II. Methods: Isolated cat papillary muscles were used for force, pHi, [Na+]i and [Ca2+]i measurements and isolated cat myocytes for patch-clamp experiments. Results: In papillary muscles, 1.0 nmol/l angiotensin II increased force by 23±2% (n=4, P+]i by 2.2±0.2 mmol/l (n=4, P2+ from 0.674±0.11 to 0.768±0.13 μmol/l (n=4, P+]i increase were abolished by inhibition of the Na+/H+ exchanger (NHE) with the inhibitor HOE642, blockade of endothelin receptors with the nonselective antagonist TAK044 and by inhibition of the endothelin-converting enzyme with phosphoramidon. Force but not [Na+]i increase was abolished by inhibition of reverse Na+/Ca2+ exchange (NCX) with the inhibitor KB-R7943. Similar increase in force (21±2%, n=4, P+]i (2.4±0.4 mmol/l, n=4, P+]i. In isolated myocytes, exogenous endothelin-1 dose-dependently increased the NCX current and shifted the NCX reversal potential (ENCX) to a more negative value (ΔENCX: -10±3 and -17±5 mV, with 1 and 10 nmol/l endothelin-1, respectively, n=12). The latter effect was prevented by HOE642. Conclusion: Taken together, the results indicate that a low dose of angiotensin II induces release of endothelin, which, in autocrine/paracrine fashion activates the Na+/H+ exchanger, increases [Na+]i and changes ENCX, promoting the influx of Ca2+ that leads to a positive inotropic effect (PIE).Facultad de Ciencias MédicasCentro de Investigaciones Cardiovasculare

A low dose of angiotensin II increases inotropism through activation of reverse Na+/Ca2+ exchange by endothelin release

Objective: This work was aimed to prove that release/formation of endogenous endothelin acting in an autocrine/paracrine fashion contributes to the increase in contractility promoted by a low dose of angiotensin II. Methods: Isolated cat papillary muscles were used for force, pHi, [Na+]i and [Ca2+]i measurements and isolated cat myocytes for patch-clamp experiments. Results: In papillary muscles, 1.0 nmol/l angiotensin II increased force by 23±2% (n=4, P+]i by 2.2±0.2 mmol/l (n=4, P2+ from 0.674±0.11 to 0.768±0.13 μmol/l (n=4, P+]i increase were abolished by inhibition of the Na+/H+ exchanger (NHE) with the inhibitor HOE642, blockade of endothelin receptors with the nonselective antagonist TAK044 and by inhibition of the endothelin-converting enzyme with phosphoramidon. Force but not [Na+]i increase was abolished by inhibition of reverse Na+/Ca2+ exchange (NCX) with the inhibitor KB-R7943. Similar increase in force (21±2%, n=4, P+]i (2.4±0.4 mmol/l, n=4, P+]i. In isolated myocytes, exogenous endothelin-1 dose-dependently increased the NCX current and shifted the NCX reversal potential (ENCX) to a more negative value (ΔENCX: -10±3 and -17±5 mV, with 1 and 10 nmol/l endothelin-1, respectively, n=12). The latter effect was prevented by HOE642. Conclusion: Taken together, the results indicate that a low dose of angiotensin II induces release of endothelin, which, in autocrine/paracrine fashion activates the Na+/H+ exchanger, increases [Na+]i and changes ENCX, promoting the influx of Ca2+ that leads to a positive inotropic effect (PIE).Facultad de Ciencias MédicasCentro de Investigaciones Cardiovasculare

Encapsulation of copper nanoparticles in electrospun nanofibers for sustainable removal of pesticides

Producción CientíficaThe excellent catalytic properties of copper nanoparticles (CuNPs) for the degradation of the highly toxic and recalcitrant chlorpyrifos pesticide are widely known. However, CuNPs generally present low stability caused by their high sensitivity to oxidation, which leads to a change of the catalytic response over time. In the current work, the immobilization of CuNPs into a polycaprolactone (PCL) matrix via electrospinning was demonstrated to be a very effective method to retard air and solvent oxidation and to ensure constant catalytic activity in the long term. CuNPs were successfully anchored into PCL electrospun fibers in the form of Cu2O at different concentrations (from 1.25 wt % to 5 wt % with respect to the PCL), with no signs of loss by leaching out. The PCL mats loaded with 2.5 wt % Cu (PCL-2.5Cu) almost halved the initial concentration of pesticide (40 mg/L) after 96 h. This process was performed in two unprompted and continuous steps that consisted of adsorption, followed by degradation. Interestingly, the degradation process was independent of the light conditions (i.e., not photocatalytic), expanding the application environments (e.g., groundwaters). Moreover, the PCL-2.5Cu composite presents high reusability, retaining the high elimination capability for at least five cycles and eliminating a total of 100 mg/L of chlorpyrifos, without exhibiting any sign of morphological damages.Ministerio de Ciencia e Innovación (PID2021-127108OB-I00)Ministerio de Ciencia e Innovación (MCIN/AEI/ 10.13039/501100011033)EU NextGenerationEU/PRTR program (PLEC2021-007705)Ministerio de Ciencia, Innovación and Ministerio de Universidades - FEDER (RTI2018−098749−B-I00 and RTI2018−097367-A-I00)Junta de Castilla y León and EU-FEDER program (CLU-2019-04 and VA202P20