Individual fitness correlates in the Black-tailed godwit

Kurzfassung der Dissertation an der Universität Groningen, NL. Arbeitsgruppe Animal Ecology, betreut durch Prof. Theunis Piersma und Dr. Christiaan Bot

Arms control and British and French nuclear forces

http://archive.org/details/armscontrolbriti00schrNAN

Digital resources and their role in advanced service provision:a VRIN analysis

Purpose: We examine the role of digital resources in the context of advanced service provision to determine their strategic potential. Approach: We conduct a theoretical review of the literature to identify digital resources which we subsequently analyse with regards to their value, rarity, inimitability and non-substitutability (VRIN). Findings: Our analysis shows that the strategic value of the digital resources is unlocked through their complementarity. Value: The research has implications for the management of advanced services and contributes towards the grounding of servitization research in the wider economic and management theory

Grutto’s het jaar rond:balans tussen reproductie en sterfte

Grutto’s komen voor korte tijd naar Nederland om te broeden, en verblijven de rest van het jaar elders. In dit artikel geven we aan hoe weinig we eigenlijk weten van ‘onze’ grutto’s in de rest van het jaar. Deze kennis is nodig om tot een goed beleid te komen voor bescherming van grutto’s in Nederland en daarbuiten

Indirect genetic effects increase heritability estimates for male and female extra-pair reproduction

The question of why females engage in extra-pair behaviors is long-standing in evolutionary biology. One suggestion is that these behaviors are maintained through pleiotropic effects on male extra-pair behaviors (genes controlling extra-pair reproduction are shared between sexes, but only beneficial to one sex, in this case, males). However, for this to evolve extra-pair reproduction must be both heritable and positively genetically correlated between sexes. Previous studies have suggested low heritability with no evidence for between-sex genetic correlations in extra-pair reproduction. However, these have not considered indirect genetic effects (derived from the behavior of others, IGEs) from the social partner, the influence of the social partner’s genotype on the phenotype of an individual, despite the potential of IGEs to uncover hidden heritable variation. Using data from a closed-house sparrow population with a genetic pedigree spanning two decades, we tested the influence of social partner IGEs on heritable variation and genetic correlation estimates of extra-pair reproduction. We found that the inclusion of IGEs resulted in larger heritable genetic variance for both male and female extra-pair heritability. While IGEs did not change between-sex genetic correlations, we found they reduced uncertainty in those estimates. Future studies should consider the effect of IGEs on the mechanisms of sex-specific extra-pair reproduction

Mature sperm small-RNA profile in the sparrow: implications for transgenerational effects of age on fitness.

Mammalian sperm RNA has recently received a lot of interest due to its involvement in epigenetic germline inheritance. Studies of epigenetic germline inheritance have shown that environmental exposures can induce effects in the offspring without altering the DNA sequence of germ cells. Most mechanistic studies were conducted in laboratory rodents and C.elegans while observational studies confirm the phenotypic phenomenon in wild populations of humans and other species including birds. Prominently, paternal age in house sparrows affects offspring fitness, yet the mechanism is unknown. This study provides a first reference of house sparrow sperm small RNA as an attempt to uncover their role in the transmission of the effects of paternal age on the offspring. In this small-scale pilot, we found no statistically significant differences between miRNA and tRNA fragments in aged and prime sparrow sperm. These results indicate a role of other epigenetic information carriers, such as distinct RNA classes, RNA modifications, DNA methylation and retained histones, and a clear necessity of future studies in wild populations.This work was supported by Cancer Research UK (C13474/A18583, C6946/A14492) and the Wellcome Trust (104640/Z/14/Z, 092096/Z/10/Z) through E.A.M. W.M. was funded by The Nakajima Foundation and St John’s College Benefactors’ Scholarship. K.G. received funding from the Swiss National Science Foundation advanced mobility fellowship. J.S. was supported by Imperial College London

Manipulating Fibroblast Environment to Study Specific Gene Expression

We investigated a model system for cardiac fibrosis. Cardiac fibrosis is the thickening of the heart wall due to the inappropriate proliferation of cardiac fibroblasts and excess deposition of extracellular matrix in the cardiac muscle. To understand how the cells, respond to stress, we analyzed changes in gene expression. Our research imitated the stress conditions that the heart cells experience. We chose to analyze genes that have not previously been characterized under uniaxial, biaxial and stress-free environments to look at how gene expression varies under different conditions. We normalized all data to a validated housekeeping genes. This research will help people with various heart problems in repairing damaged tissue. We expect to increase the understanding of the cause of cardiac fibrosis and contribute to a solution. Our conclusions will compare gene expression during healthy conditions to damage repair conditions

A meta-analysis on the heritability of vertebrate telomere length

Telomere dynamics are linked with both cellular and organismal senescence, and life history, individual quality and health. Telomere dynamics, particularly telomere length, have therefore garnered much research interest in evolutionary biology. To examine the evolution of telomere length, it is important to quantify its heritability, the proportion of total variation explained by additive genetic effects. Many studies have quantified telomere length heritability, but estimates are varied, and no general conclusion has been drawn. Additionally, it is unclear whether biological and methodological factors influence telomere length heritability estimates. We present the first meta-analysis of telomere length heritability, using 104 estimates from 43 studies over 18 vertebrate species. We calculated an overall mean heritability and examined how estimates varied by study, phylogeny, species-specific ecology, environmental setting, age at sampling, laboratory methods, statistical methods, sex and repeated measurements. Overall heritability was moderate (44.9%, 95% CI: 25.2-64.7%), and there was considerable heterogeneity in heritability estimates, in particular among studies and estimates. Laboratory method influenced heritability estimates, with in-gel hybridization TRF yielding higher heritabilities than qPCR and Southern blot TRF. There was also an effect from statistical method, with twin-based and SNP-based estimates lower than correlation-based or pedigree-based estimates. Our results highlight an overall heritable basis of telomere length, and we recommend future research on a wider range of taxa, and the use of variance-partitioning methods with relatedness or SNP data over correlation methods to minimize heritability estimation bias

Phase transition in a stochastic prime number generator

We introduce a stochastic algorithm that acts as a prime number generator. The dynamics of such algorithm gives rise to a continuous phase transition which separates a phase where the algorithm is able to reduce a whole set of integers into primes and a phase where the system reaches a frozen state with low prime density. We present both numerical simulations and an analytical approach in terms of an annealed approximation, by means of which the data are collapsed. A critical slowing down phenomenon is also outlined.Comment: accepted in PRE (Rapid Comm.