2,091 research outputs found
Does kin discrimination promote cooperation?
No full textFunding: Natural Environment Research Council Independent Research Fellowship (Grant Number NE/K009524/1) and a European Research Council Consolidator grant no. (771387) (A.G.).Genetic relatedness is a key driver of the evolution of cooperation. One mechanism that may ensure social partners are genetically related is kin discrimination, in which individuals are able to distinguish kin from non-kin and adjust their behaviour accordingly. However, the impact of kin discrimination upon the overall level of cooperation remains obscure. Specifically, while kin discrimination allows an individual to help more-related social partners over less-related social partners, it is unclear whether and how the population average level of cooperation that is evolutionarily favoured should differ under kin discrimination versus indiscriminate social behaviour. Here, we perform a general mathematical analysis in order to assess whether, when and in which direction kin discrimination changes the average level of cooperation in an evolving population. We find that kin discrimination may increase, decrease or leave unchanged the average level of cooperation, depending upon whether the optimal level of cooperation is a convex, concave or linear function of genetic relatedness. We develop an extension of the classic ‘tragedy of the commons' model of cooperation in order to provide an illustration of these results. Our analysis provides a method to guide future research on the evolutionary consequences of kin discrimination.Peer reviewe
Simultaneous failure of two sex-allocation invariants : implications for sex-ratio variation within and between populations
No full textThis research was supported by Wolfson College Cambridge (A.M.M.R.) and the Natural Environment Research Council (grant no. NE/K009524/1) (A.G.).Local mate competition (LMC) occurs when male relatives compete for mating opportunities, and may favour the evolution of female-biased sex allocation. LMC theory is among the most well-developed and empirically-supported topics in behavioural ecology, clarifies links between kin selection, group selection and game theory, and provides among the best quantitative evidence for Darwinian adaptation in the natural world. Two striking invariants arise from this body of work: the number of sons produced by each female is independent of both female fecundity and also the rate of female dispersal. Both of these invariants have stimulated a great deal of theoretical and empirical research. Here we show that both of these invariants break down when variation in female fecundity and limited female dispersal are considered in conjunction. Specifically, limited dispersal of females following mating leads to local resource competition (LRC) between female relatives for breeding opportunities, and the daughters of high-fecundity mothers experience such LRC more strongly than do those of low-fecundity mothers. Accordingly, high-fecundity mothers are favoured to invest relatively more in sons, and low-fecundity mothers are favoured to invest relatively more in daughters, and the overall sex ratio of the population sex ratio becomes more female biased as a result.Peer reviewe
Review of Historical Events (pg.7)
No full textDr. A.G. Rudovic's description of the history of the Red Army invasions of Latvia, Estonia and Lithuania and what occured when the Soviet Union forcebly incorporated masses of innocent people into Soviet GULAGS and Soviet laour camps by means of mass deportatio: as well as the loss of church spiritual leaders and forbidden church services.2.0 Imanta, 2.1.7 Baltic Nations, 2.1.3 Current Latvian Histopry in Europe ( Pre-Post WWII
Moscow doctor A.G. Dreytser – author of "The Notes of an Ambulance physician"
No full textWe have attempted to present the scientific biography of Alexander Grigorievich Dreytser, the author of "The Notes of an Ambulance physician" – a popular documentary work on the life of Moscow and Muscovites during the Great Patriotic War. We have reconstructed the main points of life and activities of A.G. Dreytser and discovered a number of facts in his biography related to his studying at Strasbourg University (1911–1914) and Imperial Moscow University (1915–1917), participation in the First World War and activities in 1918–1941. The analysis of the materials stored in the State Archive of the Russian Federation, the Central State Archive of the City of Moscow, the Russian State Archive of Literature and Art, as well as the personal archive of the Dreytser family, allowed us to clarify many points related to Dreytser's life and activities during the time prior to the creation of The Notes. This article is based upon the results of a comparative analysis of the texts of The Notes and A.G. Dreytser's Ph.D. dissertation "The Material on the Question of Sudden Death: According to the Data of Morgues, Moscow City Emergency Stations and the Department of Clinical Examination of the Central Polyclinic of the People's Commissariat for Health of the USSR". This article considers the hypothesis of the unity of the events that took place in Moscow during the Great Patriotic War and were described in the dissertation and The Notes. More complete historical and biographical data on A.G. Dreytser allowed us to prove the documentary nature of The Notes, expand the scope of known facts about the organisation of medicine during the war and clarify some circumstances of the history of Russian medicine as a whole
Adopting kin enhances inclusive fitness in asocial red squirrels
No full textOrphaned animals benefit from being adopted, but it is unclear why an adopting parent should
incur the costs of rearing extra young. Such altruistic parental behaviour could be favoured if it
is directed towards kin and the inclusive benefits of adoption exceed the costs. Here, we report
the occurrence of adoption (five occurrences among 2,230 litters over 19 years) in asocial red
squirrels (Tamiasciurus hudsonicus). Adoptions were always between kin, while orphans without nearby kin were never adopted. Adoptions were confined exclusively to circumstances in which the benefits to the adopted juvenile (b), discounted by the degree of relatedness between the surrogate and the orphan (r), exceeded the fitness costs of adding an extra juvenile to her
litter (c), as predicted by Hamilton's rule (rb>c) for the evolution of altruism. By focusing on
adoption in an asocial species, our study provides a clear test of Hamilton's rule that explains
the persistence of occasional altruism in a natural mammal population.https://viuspace.viu.ca/bitstream/handle/10613/3207/Gorrell.NC.pdf?sequence=4This is an electronic version of an article that was originally published as: Gorrell, J.C., McAdam, A.G.,
Coltman, D.W., Humphries, M.M., & Boutin, S. (2010). Adopting kin enhances inclusive fitness in asocial
red squirrels. Nature Communications, 1, 1-4. DOI: 10.1038/ncomss1022.
Nature Communications is published by Macmillan Publishers, part of Springer Nature. More
information about the journal can be found at: http://www.nature.com/ncomms/. This article can be
accessed on the Nature.com website at: http://www.nature.com/articles/ncomms1022
A modified Rayleigh conjecture for static problems
No full textAbstractA modified Rayleigh conjecture (MRC) in scattering theory was proposed and justified by the author [A.G. Ramm, Modified Rayleigh conjecture and applications, J. Phys. A 35 (2002) L357–L361]. The MRC allows one to develop efficient numerical algorithms for solving boundary-value problems. It gives an error estimate for solutions. In this paper the MRC is formulated and proved for static problems
The influence of steady blowing and roughness on transitional separated boundary layers
No full textThis paper presents the results of a study between two types of forcing, namely steady blowing and a tripwire, on the control of laminar separated boundary layers. The analysis focuses on the differences in the transition process between these two types of forcing. This effect will be studied using direct numerical simulation. The main differences consists in the coherent structures formed during transition and the overall kinetic energy growth
Andries Vierlingh, Tractaet van dyckagie (eds. J. de Hullu en A.G. Verhoeven)
No full textTranscriptie uit 1920 van het manuscript van Andries Vierlingh uit 1579 over het ontwerp en de aanleg van dijken. Zijn werk is hoofdzakelijk uitgevoerd in West Brabant. De publicatie uit 1920 is later heruitgegeven door de VBKO (Vereniging van Waterbouwers)
The constant philopater hypothesis : a new life history invariant for dispersal evolution
No full textThis research was supported by Wolfson College Cambridge (A.M.M.R.) and the Natural Environment Research Council (grant no. NE/K009524/1) (A.G.).Surprising invariance relationships have emerged from the study of social interaction, whereby a cancelling-out of multiple partial effects of genetic, ecological or demographic parameters means that they have no net impact upon the evolution of a social behaviour. Such invariants play a pivotal role in the study of social adaptation: on the one hand, they provide theoretical hypotheses that can be empirically tested; and, on the other hand, they provide benchmark frameworks against which new theoretical developments can be understood. Here we derive a novel invariant for dispersal evolution: the “constant philopater hypothesis” (CPH). Specifically, we find that, irrespective of variation in maternal fecundity, all mothers are favoured to produce exactly the same number of philopatric offspring, with high-fecundity mothers investing proportionally more, and low-fecundity mothers investing proportionally less, into dispersing offspring. This result holds for female and male dispersal, under haploid, diploid and haplodiploid modes of inheritance, irrespective of the sex ratio, local resource availability, and whether mother or offspring controls the latter’s dispersal propensity. We explore the implications of this result for evolutionary conflicts of interest – and the exchange and withholding of contextual information – both within and between families, and we show that the CPH is the fundamental invariant that underpins and explains a wider family of invariance relationships that emerge from the study of social evolution.Peer reviewe
Group stability and homing behavior but no kin group structures in a coral reef fish
No full textUnderstanding the reasons behind stable group formations has received considerable theoretical and empirical attention. Stable groups displaying homing behavior have been suggested to form as a result of, for instance, benefits from knowledge of the social or physical environment or through kin selection and the forming of kin groups. However, no one has disentangled preference for grouping in a familiar location from preference for grouping with familiar or related individuals. To investigate this, we conducted a series of field experiments and a group genetic analysis on the group-living Banggai cardinalfish (Pterapogon kauderni). We found homing behavior but no evidence for recognition of familiar group members. Instead, homing was based on the original location of their group rather than the individuals in that group. Moreover, we found no evidence for kin structures within these groups. We suggest that benefits from living in a known social environment drive homing behavior in this species and that homing behavior is not enough for the formation of kin group structures. Instead, our results suggest that kin recognition may be a prerequisite for the forming of kin groups. Copyright 2005.dispersal; group stability; kin selection; microsatellites; territory
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