The Wright-Fisher model is a discrete-time model for the genetic evolution of a finite haploid population of constant size 2N, where each individual is of type say A or a. Time starts at n = 0 and...Show moreThe Wright-Fisher model is a discrete-time model for the genetic evolution of a finite haploid population of constant size 2N, where each individual is of type say A or a. Time starts at n = 0 and at each unit of time n ∈ N, each individual randomly chooses an individual from the previous generation and adopts its type. The probability that type a goes extinct equals the initial fraction of As in the population. The genetic variability Hn at time n is the probability that two different individuals, randomly drawn from the population at time n, are of diferent type. The expectation of the time τ it takes for one of the types to go extinct equals E(τ ) = 2NH0. The Moran model is a continuous-time version of the WF-model. Making a space-time rescaling and sending the population size to infinity leads to a convergence of both the WF-model and the Moran model to the diffusion limit (Yt)t≥0 known as the WF-diffusion. The latter is dual to a pure death process (Dt)t≥0 from which the the (Kingman) coalescent (Rt)t≥0, describing the genealogy of a large (haploid) population, can be constructed. The different states through which (Rt)t≥0 evolves form the jump chain of which the transition probabilities can be calculated. Consider a population at time t that has been evolving indefinitely in accordance with (Yt)t≥0, then all the individuals in the population a.s. have a most recent common ancestor (MRCA) that lived at time At < t. The expectation of the (rescaled) time between the population and its MRCA equals E(t − At) = 2. At any time t, there are two oldest families in the population. The time Ft at which one of these families dies out, the other family fixates in the population, which causes a jump of the MRCA. Using [2] it is possible to conclude that the MRCA-process (At)t≥0 and the fixation process (Ft)t≥0 are rate-1 Poisson processes.Show less
In this thesis we discuss Poisson matchings, which can be seen as ’random graphs’ with an infinite set of random vertices U ⊂ R. The set ’U’ is the set of ’arrival times’ in a Poisson process. It...Show moreIn this thesis we discuss Poisson matchings, which can be seen as ’random graphs’ with an infinite set of random vertices U ⊂ R. The set ’U’ is the set of ’arrival times’ in a Poisson process. It is our goal to gain more insight in a specific matching type called the ’stable multi-matching’, which has some extra nice properties. We are mainly concerned with the question whether infinite components exist in these random graphs . In this paper we will study this question for the stable multi-matching with a specific degree distribution. Showing the existence of an infinite component in this matching is still an open question, but an overwhelming amount of simulation results seems to suggest a positive answer. We will also add our simulation results in support of the conjecture that such an infinite component does exist (with probability 1). We will mainly use and study the work of Alexander Holroyd and for many results will refer to his papers on this subject. Also, we try to give the reader some impression of the arguments involved in proving statements about geometric properties of the Poisson matchings. Intuitively some of these problems can seem misleadingly simple, but often there’s many subtleties and difficult mathematics involved in proving statements about geometric properties. So, don’t be misleaded by easy questions with difficult answers!Show less
The oxidation of CO on the Pd(100)(√ 5 × √ 5)R27◦ surface is studied using the kinetic Monte Carlo simulation method. The occupation by oxygen of a specific type of site – the hollow sites – is...Show moreThe oxidation of CO on the Pd(100)(√ 5 × √ 5)R27◦ surface is studied using the kinetic Monte Carlo simulation method. The occupation by oxygen of a specific type of site – the hollow sites – is monitored in order to gain insight into experiments on the restructuring of the surface which itself might be a explanation of oscillations measured in the reactivity in the oxidation reaction. Two indications have been found that oxygen atoms will only vacate the hollow sites that are they normally occupy in a clean oxidized surface if their place is taken by CO molecules.Show less
The oxidation of CO on the Pd(100)(√ 5 × √ 5)R27◦ surface is studied using the kinetic Monte Carlo simulation method. The occupation by oxygen of a specific type of site – the hollow sites – is...Show moreThe oxidation of CO on the Pd(100)(√ 5 × √ 5)R27◦ surface is studied using the kinetic Monte Carlo simulation method. The occupation by oxygen of a specific type of site – the hollow sites – is monitored in order to gain insight into experiments on the restructuring of the surface which itself might be a explanation of oscillations measured in the reactivity in the oxidation reaction. Two indications have been found that oxygen atoms will only vacate the hollow sites that are they normally occupy in a clean oxidized surface if their place is taken by CO molecules.Show less
De vondsten uit Wijchen-Berendonk behoren tot de zogenaamde 'werkvoorraad' van het Odyssee-programma. Deze werkvoorraad bestaat uit inventarisaties van oude (nood) opgravingen die nooit zijn...Show moreDe vondsten uit Wijchen-Berendonk behoren tot de zogenaamde 'werkvoorraad' van het Odyssee-programma. Deze werkvoorraad bestaat uit inventarisaties van oude (nood) opgravingen die nooit zijn uitgewerkt. Men heeft - verspreid over verschillende opgravingscampagnes - voor 4 jaar opgegraven tussen de periode van 1976-1980. Tijdens het aanleggen van enkele proefputten stuitten men al op enkele stukken vuursteen die destijds werden aangemerkt als 'Vlaardingencultuur'. Deze scriptie is met name gericht op het beantwoorden van enkele basale vragen als: waaruit bestaat het vuursteen en over welke cultuurgroepen/perioden spreken we? Uit het onderzoek bleek dat er met name uitgangsmatriaal, productiemateriaal en diverse werktuigen zijn gevonden. Verder bleek met zekerheid dat er Neolitisch materiaal aanwezig is maar er twijfel bestaat of er ook Mesolitisch en/of Bronstijd materiaal aanwezig voorkomt. Duidelijke bewoningspsoren - op basis van het onderzoek naar vuursteen - ontbreken voor zowel het Mesolithicum als het Neolithicum.Show less
Deze paper beschrijft de het proces van vrouwenbesnijdenis bestrijding in Mali, Mauritanië en Somalië. Hierbij is ook gekeken in hoeverre deze regimes gevoelig zijn voor druk van binnenlandse en...Show moreDeze paper beschrijft de het proces van vrouwenbesnijdenis bestrijding in Mali, Mauritanië en Somalië. Hierbij is ook gekeken in hoeverre deze regimes gevoelig zijn voor druk van binnenlandse en transnationale organisaties tijdens de bestrijding van vrouwenbesnijdenis.Show less
In een steeds sterker geglobaliseerde wereld worden mensen beïnvloed door de gevolgen van besluiten die staten waarvan zij geen onderdeel uitmaken, nemen. In deze scriptie wordt een poging gedaan...Show moreIn een steeds sterker geglobaliseerde wereld worden mensen beïnvloed door de gevolgen van besluiten die staten waarvan zij geen onderdeel uitmaken, nemen. In deze scriptie wordt een poging gedaan een manier te vinden om ons handelen en de consequenties daarvan te rechtvaardigen tegenover degenen die geen onderdeel van onze staat uitmaken.Show less
This thesis assesses how Direct Democracy influences Political Tolerance. It focuses on five Western democracies, i.e. Australia, Sweden, Finland, Switzerland and New Zealand. While the original...Show moreThis thesis assesses how Direct Democracy influences Political Tolerance. It focuses on five Western democracies, i.e. Australia, Sweden, Finland, Switzerland and New Zealand. While the original hypothesis that Political Tolerance is more likely in more direct democracies due to a learning effect could not be confirmed, it reveals that the issues at hand appear to be much more complex. The findings indicate that, given the issues voted on are not too diverse, respondents living in more direct democracies are more likely to allow their least-liked group to hold public office. This might indeed be due to a greater likelihood of being exposed to democratic norms, by having alternative channels to resolve conflict and by having the option to exercise a certain control over what is decided at system-level.Show less
