Effects of hatching asynchrony on sibling negotiation, begging, jostling for position and within-brood food allocation in the barn owl Tyto alba

When siblings differ markedly in their need for food, they may benefit from signalling to each other their willingness to contest the next indivisible food item delivered by the parents. This sib-sib communication system, referred to as 'sibling negotiation', may allow them to adjust optimally to investment in begging. Using barn owl (Two alba) broods. I assessed the role of within-brood age hierarchy on sibling negotiation, and in turn on jostling for position where parents predictably deliver food (i.e. nest-box entrance), begging and within-brood food allocation. More specifically, I examined three predictions derived from a game-theoretical model of sibling negotiation where a senior and a junior sibling compete for food resources (Roulin, 2002a, Johnstone and Roulin, 2003): (1) begging effort invested by the senior sibling should be less sensitive to the junior sibling's negotiation than vice versa; (2) the junior should invest less effort in sibling negotiation than its senior sibling but a similar amount of effort in begging; and (3) within-brood food allocation should be directly related to begging but only indirectly to sibling negotiation. Two-chick broods were created and vocalization in the absence (negotiation signals directed to siblings) and presence (begging signals directed to parents) of parents was recorded. In support of the first prediction, juniors begged at a low cadence after their senior sibling negotiated intensely, probably because negotiation reflects prospective investment in begging and hence willingness to compete. In contrast, the begging of senior siblings was not sensitive to their junior sibling's negotiation. In contrast to the second prediction, juniors negotiated and begged more intensely than their senior sibling apparently because they were hungrier rather than younger. In line with the third prediction, juniors monopolized food delivered by their parents when their senior sibling begged at a low level. The begging cadence of both the junior and senior sibling, the junior's negotiation cadence, the difference in age between the two nest-mates and jostling for position were not associated with the likelihood of monopolizing food. In conclusion, sibling negotiation appears to influence begging behaviour, which, in turn, affects within-brood food allocation. Juniors may negotiate to challenge their senior siblings, and thereby determine whether seniors are less hungry before deciding to beg for food. In contrast, seniors may negotiate to deter juniors from begging.

Tawny Owl Strix aluco as a bioindicator of Barn Owl Tyto alba breeding and the effect of winter severity on Barn Owl reproduction

In the temperate zone, food availability and winter weather place serious constraints on European Barn Owl Tyto alba populations. Using data collected over 22years in a Swiss population, we analysed the influence of early pre-breeding food conditions and winter severity on between-year variations in population size and reproductive performance. To estimate pre-breeding food conditions, we attempted a novel approach based on an index that combines Tawny Owl Strix aluco reproductive parameters and the occurrence of wood mice Apodemus sp. in their diet. Tawny Owls breed earlier in the season than Barn Owls and are strongly dependent on the abundance of wood mice for breeding. This index was strongly positively associated with the number of breeding pairs and early breeding in the Barn Owl. Winter severity, measured by snow cover and low temperatures, had a pronounced negative influence on the size of the breeding population and clutch size. Food conditions early in the breeding season and winter severity differentially affect the Barn Owl life cycle. We were able to use aspects of the ecology and demography of the Tawny Owl as an indicator of the quality of the environment for a related species of similar ecology, in this case the Barn Owl.

Multiple Paternity in Polyandrous Barn Owls (Tyto alba).

In polyandrous species females produce successive clutches with several males. Female barn owls (Tyto alba) often desert their offspring and mate to produce a 2(nd) annual brood with a second male. We tested whether copulating during chick rearing at the 1(st) annual brood increases the male's likelihood to obtain paternity at the 2(nd) annual breeding attempt of his female mate in case she deserts their brood to produce a second brood with a different male. Using molecular paternity analyses we found that 2 out of 26 (8%) second annual broods of deserting females contained in total 6 extra-pair young out of 15 nestlings. These young were all sired by the male with whom the female had produced the 1(st) annual brood. In contrast, none of the 49 1(st) annual breeding attempts (219 offspring) and of the 20 2(nd) annual breeding attempts (93 offspring) of non-deserting females contained extra-pair young. We suggest that female desertion can select male counter-strategies to increase paternity and hence individual fitness. Alternatively, females may copulate with the 1(st) male to derive genetic benefits, since he is usually of higher quality than the 2(nd) male which is commonly a yearling individual.

De la dificultad para integrar las TIC al servicio de una propuesta alternativa para enseñar y aprender: políticas y prácticas. El caso del Jaume I

El estudio de caso realizado en la “Escola Jaume I” forma parte del proyecto de I+D Políticas y prácticas en torno a las TIC en la enseñanza obligatoria: Implicaciones para la innovación y la mejora (Ministerio de Ciencia e Innovación. SEJ200767562), cuya finalidad principal es describir, analizar, interpretar y valorar la visión sobre la tecnología y la educación subyacente en las políticas y prácticas relacionadas con las TIC en la escuela, su grado de integración y sinergia con otras iniciativas políticas, y su capacidad para impulsar la transformación y la innovación y mejora de la educación obligatoria.

Estudi i primera fase per la implementació del FOFB al Sincrotró ALBA

Aquest treball és la culminació de les pràctiques realitzades al sincrotró ALBA. Situat a Cerdanyola del Vallès, ALBA és un accelerador de 3a generació que permet emmagatzemar un feix d'electrons confinat de fins a 400 mA a 3GeV d'energia, amb l'objectiu d'obtenir llum a partir dels girs provocats al feix. Els sincrotrons moderns com el d'ALBA, el que pretenen és aconseguir un major control i estabilitat de la llum. Per aconseguir-ho, cal que el feix d'electrons que creen la llum estigui controlat al màxim i la seva òrbita sigui estable. Amb aquest objectiu els sincrotrons estant implementant sistemes de Fast Orbit FeedBack (FOFB) o sistemes realimentats de correcció ràpida de l'òrbita, per realitzar correccions d'almenys 100Hz que estabilitzin el feix d'electrons amb menys d'un 10% de l'amplada del feix (5-10μm). El treball exposa el desenvolupament d'una part del sistema de correcció ràpida de l'òrbita dels electrons (FOFB) que s'està duent a terme al sincrotró ALBA. Concretament, s’han revisat els estudis previs realitzats durant la fase de disseny del sincrotró, s’han recalculat funcions de transferència i retards de tots els elements involucrats al sistema. També s’han realitzat simulacions per confirmar la viabilitat del sistema amb les noves dades i finalment s’ha desenvolupat part de la unitat de control determinant el Hardware i s'ha adquirit dades que permetran analitzar el soroll de l'òrbita que en futurs treballs determinaran millor l'algorisme de la unitat de control.

Isolation and characterization of major histocompatibility complex (MHC) class II B genes in the Barn owl (Aves: Tyto alba)

We isolated major histocompatibility complex class II B (MHCIIB) genes in the Barn owl (Tyto alba). A PCR-based approach combined with primer walking on genomic and complementary DNA as well as Southern blot analyses revealed the presence of two MHCIIB genes, both being expressed in spleen, liver, and blood. Characteristic structural features of MHCIIB genes as well as their expression and high non-synonymous substitution rates in the region involved in antigen binding suggest that both genes are functional. MHC organization in the Barn owl is simple compared to passerine species that show multiple duplications, and resembles the minimal essential MHC of chicken.

Extra-pair paternity, testes size and testosterone level in relation to colour polymorphism in the barn owl Tyto alba

In many bird populations, individuals display one of several genetically inherited colour morphs. Colour polymorphism can be maintained by several mechanisms one of which being frequency-dependent selection with colour morphs signalling alternative mating strategies. One morph may be dominant and territorial, and another one adopt a sneaky behaviour to gain access to fertile females. We tested this hypothesis in the barn owl Tyto alba in which coloration varies from reddish-brown to white. This trait is heritable and neither sensitive to the environment in which individuals live nor to body condition. In Switzerland, reddish-brown males were observed to feed their brood at a higher rate and to produce more offspring than white males. This observation lead us to hypothesize that white males may equalise fitness by investing more effort in extra-pair copulations. This hypothesis predicts that lighter Coloured males produce more extra-pair young, have larger testes and higher levels of circulating testosterone. However, our results are not consistent with these three predictions. First, paternity analyses of 54 broods with a total of 211 offspring revealed that only one young was not sired by the male that was feeding it. Second, testes size was not correlated with male plumage coloration suggesting that white males are not sexually more active. Finally, in nestlings at the time of feather growth testosterone level was not related to plumage coloration suggesting that this androgen is not required for the expression of this plumage trait. Our study therefore indicates that in the barn owl colour polymorphism plays no role in the probability of producing extra-pair young.

Relationship between Megastigmus suspectus borr.size and Abies alba mill.seed size

Summary

Common Barn Owl Tyto alba, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Corticosterone promotes scramble competition over sibling negotiation in Barn Owl nestlings (Tyto alba)

In species with parental care, siblings compete for access to food resources. Typically, they vocally signal their level of need to each other and to parents, and jostle for the position in the nest where parents deliver food. Although food shortage and social interactions are stressful, little is known about the effect of stress on the way siblings resolve the conflict over how food is shared among them. Because glucocorticoid hormones mediate physiological and behavioral responses to stressors, we tested whether corticosterone, the main glucocorticoid in birds, modulates physical and vocal signaling used by barn owl siblings (Tyto alba) to compete for food. Although corticosterone-implanted (cort-) nestlings and placebo-nestlings were similarly successful to monopolize food, they employed different behavioral strategies. Compared to placebo-nestlings, cort-individuals reduced the rate of vocally communicating with their siblings (but not with their parents) but were positioned closer to the nest-box entrance where parents predictably deliver food. Therefore, corticosterone induced nestlings to increase their effort in physical competition for the best nest position at the expense of investment in sib-sib communication without modifying vocal begging signals directed to parents. This suggests that in the barn owl stress alters nestlings' behavior and corticosterone could mediate the trade-off between scramble competition and vocal sib-sib communication. We conclude that stressful environments may prevent the evolution of sib-sib communication as a way to resolve family conflicts peacefully.

Barn Owl Tyto alba pratincola, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

The importance of micro-habitat in the breeding of Barn Owls Tyto alba

Capsule Habitat parameters associated with 706 Barn Owl (Tyto alba) nesting boxes in Israel were analysed. Pairs bred in 259 of the boxes. The intensity of agricultural practices at nestbox sites were shown to have only a weak effect on aspects of Barn Owl breeding in this region.

Barn Owl (Tyto alba) breeding biology in relation to breeding season climate

Winter weather has a strong influence on Barn Owl (Tyto alba) breeding biology. Here, we analyzed the impacts of weather conditions on reproductive performance during the breeding season using data collected over 22 years in a Swiss Barn Owl population. Variations in rain and temperature during the breeding season played an important role in within-year variation in Barn Owl reproduction. An increase in rainfall during the period from 4 to 2 weeks preceding egg laying had a positive effect on clutch size. In contrast, fledgling body mass was negatively influenced by rainfall during the 24 h preceding the measurements. Finally, ambient temperature during the rearing period was positively associated with brood size at fledging. In conclusion, weather conditions during the breeding season place constraints on Barn Owl reproduction.

Assessing the impact of high-pressure processing on selected physical and biochemical attributes of white cabbage (Brassica oleracea L. var. capitata alba)

The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties

Anàlisi de la motivació al canvi en subjectes que han realitzat un programa formatiu en violència domèstica

Aquesta recerca consisteix en l’avaluació de la motivació al canvi en un grup de 116 agressors que realitzen un programa formatiu en matèria de violència domèstica (VIDO) com a mesura penal alternativa. L’objectiu principal d’aquesta recerca és determinar en quin grau es produeix un canvi motivacional com a conseqüència de la participació en el programa formatiu. Amb aquest propòsit, s’avalua el risc dels individus (mitjançant l’avaluació de risc realitzada pels delegats judicials), les seves necessitats criminogèniques (mitjançant dades sociodemogràfiques i de carrera criminal), les característiques clíniques de personalitat mesurades amb l’Inventari d’Avaluació de la Personalitat (PAI) i la seva motivació per al canvi (a través de l’Escala d’Estadis de Canvi). Els resultats indiquen que els canvis en el nivell de motivació dels subjectes no es deuen a l’efecte del programa formatiu. No obstant això, es troben canvis significatius quan la motivació s’analitza en relació a les característiques del PAI. Aquests resultats suggereixen l’existència de diferents perfils de maltractadors de parella que s’han de tenir en compte a l’hora de planificar el programa formatiu per aconseguir la màxima eficàcia de les intervencions i el canvi terapèutic dels individus.