Search results for "Breeding"
showing 10 items of 475 documents
Maternal antibody transmission and breeding densities in the Black-headed Gull Larus ridibundus
2004
1. The offspring of avian species, especially those of colonial breeders, are exposed to a number of pathogens immediately after birth. The chick's immune system is, at that early stage still immature and inefficient. As a consequence, diseases can have a strong impact on chick survival.2. The ability of mothers to transmit passive immunity in terms of antibodies of their own acquired immunity to their chicks is probably an essential pathway to enhance the chick survival. Since the production of antibodies is costly, females are expected to adjust the transmission of passive immunity to the local disease environment.3. We found that in Black-headed Gulls (Larus ridibundus L.) yolk antibody …
Mother Knows Best: Dominant Females Determine Offspring Dispersal in Red Foxes (Vulpes vulpes)
2011
Background: Relatedness between group members is central to understanding the causes of animal dispersal. In many group-living mammals this can be complicated as extra-pair copulations result in offspring having varying levels of relatedness to the dominant animals, leading to a potential conflict between male and female dominants over offspring dispersal strategies. To avoid resource competition and inbreeding, dominant males might be expected to evict unrelated males and related females, whereas the reverse strategy would be expected for dominant females. Methodology/Principal Findings: We used microsatellites and long-term data from an urban fox (Vulpes vulpes) population to compare disp…
Olive embryo in vitro germination potential: Role of explant configuration and embryo structure among cultivars
2014
The in vitro germination of excised embryos can break dormancy rapidly and shorten the time required to produce seedlings, speeding up olive breeding programmes as well as rootstock production. In this study, the in vitro germination potential of four Sicilian olive cultivars was evaluated during two years of experiments, using explants with three different morphological configurations that represent three different degrees of embryo exposure: (1) intact stoneless seeds containing the embryo, the endosperm and the seed coat (Emb+En+SC), (2) seeds without the seed coat (Emb+En) and (3) naked, isolated embryos (seed coat and endosperm both removed: Emb). Differences were found in the germinat…
New insights on the role of ecology and life-history in social evolution
2017
Biological altruism, defined as a behaviour that benefits others at an apparent cost to the focal individual, is found abundantly across different levels of biological organization. While kin selection has been useful for explaining both cooperation and conflict in specialized cooperative societies, more theoretical work has to be done to develop models for realistic ecological and life-history contexts. This thesis aims to fill this gap by providing several new insights on the role of ecology and life-history in various social systems. Firstly, I propose a model that incorporates realistic ecological mechanisms of population regulation and study how different population regulation mechanisms affe…
First breeding evidence of marbled duck (Marmaronetta angustirostris) in Libya.
2014
4 pages; International audience; The first evidence of breeding of Marbled Duck (Marmaronetta angustirostris) in Libya, North Africa, is reported. In June 2012, at Mallaha wetland, in Tripoli, Libya, two dead ducklings were found that were later genetically identified as Marbled Duck. This breeding evidence suggests that this and other duck species may breed elsewhere in Libya. Better knowledge on Libyan, and more generally on north African, waterbirds is needed to document the population size and the status of these species. Such information will be important to secure the future of threatened species, such as the Marbled Duck.
Chemical Composition of the Essential Oil of the New Cultivars of Lavandula angustifolia Mill. Bred in Ukraine
2021
Lavender, otherwise known as Lavandula angustifolia Mill., is widely used in landscaping, and its oil is a valuable raw material used in many industries. Therefore, new varieties of this plant are bred. The essential oil composition obtained from fresh flowers of thirteen new Ukrainian cultivars of L. angustifolia were analysed by GC-MS, and eighty-two components were identified. Linalool and linalyl acetate were principal constituents of all of the samples, and ranged from 11.4% to 46.7% and 7.4% to 44.2%, respectively. None of the studied samples fulfilled the requirements of Ph. Eur. and ISO 3515:2002. The main reason was a high content of α-terpineol (0.5–4.5%) and/or terpinene-4-ol (1.…
The rare isotope beams production at the Texas A&M university Cyclotron Institute
2013
The Cyclotron Institute at Texas A&M is currently configuring a scheme for the production of radioactive-ion beams that incorporates a light-ion guide and a heavy-ion guide coupled with an electron-cyclotron-resonance ion source constructed for charge-breeding. This scheme is part of an upgrade to the facility and is intended to produce radioactive beams suitable for injection into the K500 superconducting cyclotron. The current status of the project and details on the ion sources used in the project is presented. peerReviewed
L'alimentation carnée à Aventicum/Avenches capitale des Helvètes (Ier s. - IVe s. apr. J.-C.) Suisse, canton de Vaud
2010
This first synthesis concerns the animal bones, discovered since 1975 in Aventicum, the capital of Roman Switzerland. It is supported by the analysis of several residential districts, public sectors and suburbs, which represent five hundred chronological complexes and 74000 animal bones, dated from the Ist, to the IVth Century AD. During these centuries, Aventicum was incorporated to the Roman province of Gallia Belgica, then was raised to the status of a colonia and finally declined with the Empire.The analysis of bones was made to study various mutations which occurred during the occupation of the city. They include an improvement of breeding techniques, a new internal city organisation, …
Moviments de dispersió en els primats. Variabilitat en els seus patrons i causes
2014
Els moviments de dispersió en els animals representen decisions crucials per als individus, ja que afecten la seua supervivència i èxit reproductiu, a més de ser un component important de la dinàmica poblacional. En aquest article es descriu la variabilitat en els patrons de dispersió en els primats i algunes de les causes, tant últimes com proximals, a les quals respon.
Novel method for determination of tritium depth profiles in metallic samples
2019
Tritium accumulation in fusion reactor materials is considered a serious radiological issue, therefore a lot of effort has been concentrated on the development of radiometric techniques. A novel method, based on gradual dissolution, for the determination of the total tritium content and its depth profiles in metallic samples is demonstrated. This method allows for the measurement of tritium in metallic samples after their exposure to a hydrogen and tritium mixture, tritium containing plasma or after irradiation with neutrons resulting in tritium formation. In this method, successive layers of metal are removed using an appropriate etching agent in the controlled regime and the amount of evo…