Individuals on the Move : Body Condition Dependent Dispersal and Quasi-Local Competition in Metapopulations

Individual movement is very versatile and inevitable in ecology. In this thesis, I investigate two kinds of movement body condition dependent dispersal and small-range foraging movements resulting in quasi-local competition and their causes and consequences on the individual, population and metapopulation level. Body condition dependent dispersal is a widely evident but barely understood phenomenon. In nature, diverse relationships between body condition and dispersal are observed. I develop the first models that study the evolution of dispersal strategies that depend on individual body condition. In a patchy environment where patches differ in environmental conditions, individuals born in rich (e.g. nutritious) patches are on average stronger than their conspecifics that are born in poorer patches. Body condition (strength) determines competitive ability such that stronger individuals win competition with higher probability than weak individuals. Individuals compete for patches such that kin competition selects for dispersal. I determine the evolutionarily stable strategy (ESS) for different ecological scenarios. My models offer explanations for both dispersal of strong individuals and dispersal of weak individuals. Moreover, I find that within-family dispersal behaviour is not always reflected on the population level. This supports the fact that no consistent pattern is detected in data on body condition dependent dispersal. It also encourages the refining of empirical investigations. Quasi-local competition defines interactions between adjacent populations where one population negatively affects the growth of the other population. I model a metapopulation in a homogeneous environment where adults of different subpopulations compete for resources by spending part of their foraging time in the neighbouring patches, while their juveniles only feed on the resource in their natal patch. I show that spatial patterns (different population densities in the patches) are stable only if one age class depletes the resource very much but mainly the other age group depends on it.

Jumping numbers of a simple complete ideal in a two-dimensional regular local ring

The multiplier ideals of an ideal in a regular local ring form a family of ideals parametrized by non-negative rational numbers. As the rational number increases the corresponding multiplier ideal remains unchanged until at some point it gets strictly smaller. A rational number where this kind of diminishing occurs is called a jumping number of the ideal. In this manuscript we shall give an explicit formula for the jumping numbers of a simple complete ideal in a two dimensional regular local ring. In particular, we obtain a formula for the jumping numbers of an analytically irreducible plane curve. We then show that the jumping numbers determine the equisingularity class of the curve.

Understanding local processes: Contemplating franchisation

Increasing, there is growing acknowledgement of the importance of franchising within all modern global economies. Despite this, little is understood with regards the actual impact of franchising on local economies. This research aims to reframe the contribution of franchising by considering the process of franchisation. This study employed a mixed-method approach, utilizing critical realism to facilitate an outcomes-based explanation of firm survival. The focus of the study was upon generative mechanisms that were assumed to give rise to particular events from which (pizza) firm survival was enhanced vis-à-vis all other community members. A database of 2440 firms (or in excess of 21,000 company years) combined with archival records, interviews and the researcher’s observations provided the researcher with access to the nature of interaction occurring between firms. It was found that the survival of local firms was influenced positively by the day-to-day actions of franchise operators. However, it is argued that to understand how any such advantage my fall to local independent firms, we need too better appreciate the multitude of local processes related to such industries. This research re-examines several ecological concepts with the view of enabling a clearer investigation of underlying local processes. It also represents an authentic autecological approach to the study of firms.

Computational Techniques for Haplotype Inference and for Local Alignment Significance

This thesis which consists of an introduction and four peer-reviewed original publications studies the problems of haplotype inference (haplotyping) and local alignment significance. The problems studied here belong to the broad area of bioinformatics and computational biology. The presented solutions are computationally fast and accurate, which makes them practical in high-throughput sequence data analysis. Haplotype inference is a computational problem where the goal is to estimate haplotypes from a sample of genotypes as accurately as possible. This problem is important as the direct measurement of haplotypes is difficult, whereas the genotypes are easier to quantify. Haplotypes are the key-players when studying for example the genetic causes of diseases. In this thesis, three methods are presented for the haplotype inference problem referred to as HaploParser, HIT, and BACH. HaploParser is based on a combinatorial mosaic model and hierarchical parsing that together mimic recombinations and point-mutations in a biologically plausible way. In this mosaic model, the current population is assumed to be evolved from a small founder population. Thus, the haplotypes of the current population are recombinations of the (implicit) founder haplotypes with some point--mutations. HIT (Haplotype Inference Technique) uses a hidden Markov model for haplotypes and efficient algorithms are presented to learn this model from genotype data. The model structure of HIT is analogous to the mosaic model of HaploParser with founder haplotypes. Therefore, it can be seen as a probabilistic model of recombinations and point-mutations. BACH (Bayesian Context-based Haplotyping) utilizes a context tree weighting algorithm to efficiently sum over all variable-length Markov chains to evaluate the posterior probability of a haplotype configuration. Algorithms are presented that find haplotype configurations with high posterior probability. BACH is the most accurate method presented in this thesis and has comparable performance to the best available software for haplotype inference. Local alignment significance is a computational problem where one is interested in whether the local similarities in two sequences are due to the fact that the sequences are related or just by chance. Similarity of sequences is measured by their best local alignment score and from that, a p-value is computed. This p-value is the probability of picking two sequences from the null model that have as good or better best local alignment score. Local alignment significance is used routinely for example in homology searches. In this thesis, a general framework is sketched that allows one to compute a tight upper bound for the p-value of a local pairwise alignment score. Unlike the previous methods, the presented framework is not affeced by so-called edge-effects and can handle gaps (deletions and insertions) without troublesome sampling and curve fitting.

Optimisation Problems in Wireless Sensor Networks : Local Algorithms and Local Graphs

This thesis studies optimisation problems related to modern large-scale distributed systems, such as wireless sensor networks and wireless ad-hoc networks. The concrete tasks that we use as motivating examples are the following: (i) maximising the lifetime of a battery-powered wireless sensor network, (ii) maximising the capacity of a wireless communication network, and (iii) minimising the number of sensors in a surveillance application. A sensor node consumes energy both when it is transmitting or forwarding data, and when it is performing measurements. Hence task (i), lifetime maximisation, can be approached from two different perspectives. First, we can seek for optimal data flows that make the most out of the energy resources available in the network; such optimisation problems are examples of so-called max-min linear programs. Second, we can conserve energy by putting redundant sensors into sleep mode; we arrive at the sleep scheduling problem, in which the objective is to find an optimal schedule that determines when each sensor node is asleep and when it is awake. In a wireless network simultaneous radio transmissions may interfere with each other. Task (ii), capacity maximisation, therefore gives rise to another scheduling problem, the activity scheduling problem, in which the objective is to find a minimum-length conflict-free schedule that satisfies the data transmission requirements of all wireless communication links. Task (iii), minimising the number of sensors, is related to the classical graph problem of finding a minimum dominating set. However, if we are not only interested in detecting an intruder but also locating the intruder, it is not sufficient to solve the dominating set problem; formulations such as minimum-size identifying codes and locating dominating codes are more appropriate. This thesis presents approximation algorithms for each of these optimisation problems, i.e., for max-min linear programs, sleep scheduling, activity scheduling, identifying codes, and locating dominating codes. Two complementary approaches are taken. The main focus is on local algorithms, which are constant-time distributed algorithms. The contributions include local approximation algorithms for max-min linear programs, sleep scheduling, and activity scheduling. In the case of max-min linear programs, tight upper and lower bounds are proved for the best possible approximation ratio that can be achieved by any local algorithm. The second approach is the study of centralised polynomial-time algorithms in local graphs these are geometric graphs whose structure exhibits spatial locality. Among other contributions, it is shown that while identifying codes and locating dominating codes are hard to approximate in general graphs, they admit a polynomial-time approximation scheme in local graphs.

Gene flow from Corymbia hybrids in northern New South Wales

Some of the most productive taxa for forestry are interspecific F1 hybrids grown as exotics in the tropics and subtropics. Attributes of resilience, adaptability and vigour which engender the hybrids for wood production, may also exacerbate the risk they present from gene flow to native species gene pools or to local ecologies as weeds. To determine the biological and genetic factors that influence the extent of hybridisation, we examine the distribution and genealogy of wildlings surrounding plantings of locally-exotic Corymbia torelliana (Section Cadageria) near native C. henryi (Section Maculatae) in northern New South Wales. Our study showed pre-mating and pre- and post-zygotic barriers were incomplete, with in situ generation and natural establishment of both F1 hybrids (n = 3) and advanced generation hybrids under the disturbed conditions bordering native forest. As hybrids were located on alluvial flats exposed to frost, they also likely have an extended ecological range relative to native C. henryi. Despite the likely generation of large viable seed crops on F1 trees at the site over many years, establishment success and survival of advanced generation hybrids may be low, as only 5 immature and no mature advanced generation hybrids were identified. Propagation and genetic analysis of a seed crop from one F1 wildling showed early survival and vigour of seedlings in cultivation was high, and that at least for some F1 in some seasons, backcrossing to the recurrent native C. henryi parent is favoured (60%), whereas selfing (10%) and crossing with other F1 (30%) was less frequent. Transport of seed by stingless bees probably accounted for long distance dispersal from C. torelliana, but this mechanism does not appear to supplement gravity-dispersal of seed from the F1. Coupled with other evidence from studies of bee behaviour, controlled pollination in Corymbia sp., and long-term fitness in second generation eucalypt hybrids, we anticipate gene flow via pollen rather than seed will be the greater challenge for managing the risk of introgression of C. torelliana ancestry into native species from the planted F1 hybrid. If large sources of F1 pollen become available to compete with native pollen, gene flow will probably be frequent and hybrids may establish in disturbed conditions and in habitats beyond the ecological range of their native parent. Further study is needed to determine the degree to which outbreeding depression and poor survival inhibits on-going gene flow.

Greenwashing the Trans-Pacific Partnership: Fossil fuels, the environment, and climate change

There has been much controversy over the Trans-Pacific Partnership (TPP) – a plurilateral trade agreement involving a dozen nations from throughout the Pacific Rim – and its impact upon the environment, biodiversity, and climate change. The secretive treaty negotiations involve Australia and New Zealand; countries from South East Asia such as Brunei Darussalam, Malaysia, Singapore, Vietnam, and Japan; the South American nations of Peru and Chile; and the members of the 1994 North American Free Trade Agreement (NAFTA), Canada, Mexico and the United States. There was an agreement reached between the parties in October 2015. The participants asserted: ‘We expect this historic agreement to promote economic growth, support higher-paying jobs; enhance innovation, productivity and competitiveness; raise living standards; reduce poverty in our countries; and to promote transparency, good governance, and strong labor and environmental protections.’ The final texts of the agreement were published in November 2015. There has been discussion as to whether other countries – such as Indonesia, the Philippines, and South Korea – will join the deal. There has been much debate about the impact of this proposed treaty upon intellectual property, the environment, biodiversity and climate change. There have been similar concerns about the Trans-Atlantic Trade and Investment Partnership (TTIP) – a proposed trade agreement between the United States and the European Union. In 2011, the United States Trade Representative developed a Green Paper on trade, conservation, and the environment in the context of the TPP. In its rhetoric, the United States Trade Representative has maintained that it has been pushing for strong, enforceable environmental standards in the TPP. In a key statement in 2014, the United States Trade Representative Mike Froman insisted: ‘The United States’ position on the environment in the Trans-Pacific Partnership negotiations is this: environmental stewardship is a core American value, and we will insist on a robust, fully enforceable environment chapter in the TPP or we will not come to agreement.’ The United States Trade Representative maintained: ‘Our proposals in the TPP are centered around the enforcement of environmental laws, including those implementing multilateral environmental agreements (MEAs) in TPP partner countries, and also around trailblazing, first-ever conservation proposals that will raise standards across the region’. Moreover, the United States Trade Representative asserted: ‘Furthermore, our proposals would enhance international cooperation and create new opportunities for public participation in environmental governance and enforcement.’ The United States Trade Representative has provided this public outline of the Environment Chapter of the TPP: A meaningful outcome on environment will ensure that the agreement appropriately addresses important trade and environment challenges and enhances the mutual supportiveness of trade and environment. The Trans-Pacific Partnership countries share the view that the environment text should include effective provisions on trade-related issues that would help to reinforce environmental protection and are discussing an effective institutional arrangement to oversee implementation and a specific cooperation framework for addressing capacity building needs. They also are discussing proposals on new issues, such as marine fisheries and other conservation issues, biodiversity, invasive alien species, climate change, and environmental goods and services. Mark Linscott, an assistant Trade Representative testified: ‘An environment chapter in the TPP should strengthen country commitments to enforce their environmental laws and regulations, including in areas related to ocean and fisheries governance, through the effective enforcement obligation subject to dispute settlement.’ Inside US Trade has commented: ‘While not initially expected to be among the most difficult areas, the environment chapter has emerged as a formidable challenge, partly due to disagreement over the United States proposal to make environmental obligations binding under the TPP dispute settlement mechanism’. Joshua Meltzer from the Brookings Institute contended that the trade agreement could be a boon for the protection of the environment in the Pacific Rim: Whether it is depleting fisheries, declining biodiversity or reduced space in the atmosphere for Greenhouse Gas emissions, the underlying issue is resource scarcity. And in a world where an additional 3 billion people are expected to enter the middle class over the next 15 years, countries need to find new and creative ways to cooperate in order to satisfy the legitimate needs of their population for growth and opportunity while using resources in a manner that is sustainable for current and future generations. The TPP parties already represent a diverse range of developed and developing countries. Should the TPP become a free trade agreement of the Asia-Pacific region, it will include the main developed and developing countries and will be a strong basis for building a global consensus on these trade and environmental issues. The TPP has been promoted by its proponents as a boon to the environment. The United States Trade Representative has maintained that the TPP will protect the environment: ‘The United States’ position on the environment in the TPP negotiations is this: environmental stewardship is a core American value, and we will insist on a robust, fully enforceable environment chapter in the TPP or we will not come to agreement.’ The United States Trade Representative discussed ‘Trade for a Greener World’ on World Environment Day. Andrew Robb, at the time the Australian Trade and Investment Minister, vowed that the TPP will contain safeguards for the protection of the environment. In November 2015, after the release of the TPP text, Rohan Patel, the Special Assistant to the President and Deputy Director of Intergovernmental Affairs, sought to defend the environmental credentials of the TPP. He contended that the deal had been supported by the Nature Conservancy, the International Fund for Animal Welfare, the Joint Ocean Commission Initiative, the World Wildlife Fund, and World Animal Protection. The United States Congress, though, has been conflicted by the United States Trade Representative’s arguments about the TPP and the environment. In 2012, members of the United States Congress - including Senator Ron Wyden (D-OR), Olympia Snowe (R-ME), and John Kerry (D-MA) – wrote a letter, arguing that the trade agreement needs to provide strong protection for the environment: ‘We believe that a '21st century agreement' must have an environment chapter that guarantees ongoing sustainable trade and creates jobs, and this is what American businesses and consumers want and expect also.’ The group stressed that ‘A binding and enforceable TPP environment chapter that stands up for American interests is critical to our support of the TPP’. The Congressional leaders maintained: ‘We believe the 2007 bipartisan congressional consensus on environmental provisions included in recent trade agreements should serve as the framework for the environment chapter of the TPP.’ In 2013, senior members of the Democratic leadership expressed their opposition to granting President Barack Obama a fast-track authority in respect of the TPP House of Representatives Minority Leader Nancy Pelosi said: ‘No on fast-track – Camp-Baucus – out of the question.’ Senator Majority leader Harry Reid commented: ‘I’m against Fast-Track: Everyone would be well-advised to push this right now.’ Senator Elizabeth Warren has been particularly critical of the process and the substance of the negotiations in the TPP: From what I hear, Wall Street, pharmaceuticals, telecom, big polluters and outsourcers are all salivating at the chance to rig the deal in the upcoming trade talks. So the question is, Why are the trade talks secret? You’ll love this answer. Boy, the things you learn on Capitol Hill. I actually have had supporters of the deal say to me ‘They have to be secret, because if the American people knew what was actually in them, they would be opposed. Think about that. Real people, people whose jobs are at stake, small-business owners who don’t want to compete with overseas companies that dump their waste in rivers and hire workers for a dollar a day—those people, people without an army of lobbyists—they would be opposed. I believe if people across this country would be opposed to a particular trade agreement, then maybe that trade agreement should not happen. The Finance Committee in the United States Congress deliberated over the Trans-Pacific Partnership negotiations in 2014. The new chair Ron Wyden has argued that there needs to be greater transparency in trade. Nonetheless, he has mooted the possibility of a ‘smart-track’ to reconcile the competing demands of the Obama Administration, and United States Congress. Wyden insisted: ‘The new breed of trade challenges spawned over the last generation must be addressed in imaginative new policies and locked into enforceable, ambitious, job-generating trade agreements.’ He emphasized that such agreements ‘must reflect the need for a free and open Internet, strong labor rights and environmental protections.’ Elder Democrat Sander Levin warned that the TPP failed to provide proper protection for the environment: The TPP parties are considering a different structure to protect the environment than the one adopted in the May 10 Agreement, which directly incorporated seven multilateral environmental agreements into the text of past trade agreements. While the form is less important than the substance, the TPP must provide an overall level of environmental protection that upholds and builds upon the May 10 standard, including fully enforceable obligations. But many of our trading partners are actively seeking to weaken the text to the point of falling short of that standard, including on key issues like conservation. Nonetheless, 2015, President Barack Obama was able to secure the overall support of the United States Congress for his ‘fast-track’ authority. This was made possible by the Republicans and dissident Democrats. Notably, Oregon Senator Ron Wyden switched sides, and was transformed from a critic of the TPP to an apologist for the TPP. For their part, green political parties and civil society organisations have been concerned about the secretive nature of the negotiations; and the substantive implications of the treaty for the environment. Environmental groups and climate advocates have been sceptical of the environmental claims made by the White House for the TPP. The Green Party of Aotearoa New Zealand, the Australian Greens and the Green Party of Canada have released a joint declaration on the TPP observing: ‘More than just another trade agreement, the TPP provisions could hinder access to safe, affordable medicines, weaken local content rules for media, stifle high-tech innovation, and even restrict the ability of future governments to legislate for the good of public health and the environment’. In the United States, civil society groups such as the Sierra Club, Public Citizen, WWF, the Friends of the Earth, the Rainforest Action Network and 350.org have raised concerns about the TPP and the environment. Allison Chin, President of the Sierra Club, complained about the lack of transparency, due process, and public participation in the TPP talks: ‘This is a stealth affront to the principles of our democracy.’ Maude Barlow’s The Council of Canadians has also been concerned about the TPP and environmental justice. New Zealand Sustainability Council executive director Simon Terry said the agreement showed ‘minimal real gains for nature’. A number of organisations have joined a grand coalition of civil society organisations, which are opposed to the grant of a fast-track. On the 15th January 2013, WikiLeaks released the draft Environment Chapter of the TPP - along with a report by the Chairs of the Environmental Working Group. Julian Assange, WikiLeaks' publisher, stated: ‘Today's WikiLeaks release shows that the public sweetener in the TPP is just media sugar water.’ He observed: ‘The fabled TPP environmental chapter turns out to be a toothless public relations exercise with no enforcement mechanism.’ This article provides a critical examination of the draft Environment Chapter of the TPP. The overall argument of the article is that the Environment Chapter of the TPP is an exercise in greenwashing – it is a public relations exercise by the United States Trade Representative, rather than a substantive regime for the protection of the environment in the Pacific Rim. Greenwashing has long been a problem in commerce, in which companies making misleading and deceptive claims about the environment. In his 2012 book, Greenwash: Big Brands and Carbon Scams, Guy Pearse considers the rise of green marketing and greenwashing. Government greenwashing is also a significant issue. In his book Storms of My Grandchildren, the climate scientist James Hansen raises his concerns about government greenwashing. Such a problem is apparent with the TPP – in which there was a gap between the assertions of the United States Government, and the reality of the agreement. This article contends that the TPP fails to meet the expectations created by President Barack Obama, the White House, and the United States Trade Representative about the environmental value of the agreement. First, this piece considers the relationship of the TPP to multilateral environmental treaties. Second, it explores whether the provisions in respect of the environment are enforceable. Third, this article examines the treatment of trade and biodiversity in the TPP. Fourth, this study considers the question of marine capture fisheries. Fifth, there is an evaluation of the cursory text in the TPP on conservation. Sixth, the article considers trade in environmental services under the TPP. Seventh, this article highlights the tensions between the TPP and substantive international climate action. It is submitted that the TPP undermines effective and meaningful government action and regulation in respect of climate change. The conclusion also highlights that a number of other chapters of the TPP will impact upon the protection of the environment – including the Investment Chapter, the Intellectual Property Chapter, the Technical Barriers to Trade Chapter, and the text on public procurement.

Development of a transient gradient enhanced non local continuum damage mechanics model for masonry

Due to the advent of varied types of masonry systems a comprehensive failure mechanism of masonry essential for the understanding of its behaviour is impossible to be determined from experimental testing. As masonry is predominantly used in wall structures a biaxial stress state dominates its failure mechanism. Biaxial testing will therefore be necessary for each type of masonry, which is expensive and time consuming. A computational method would be advantageous; however masonry is complex to model which requires advanced computational modelling methods. This thesis has formulated a damage mechanics inspired modelling method and has shown that the method effectively determines the failure mechanisms and deformation characteristics of masonry under biaxial states of loading.

Inhibition of Human Two-Pore Domain K+ Channel TREK1 by Local Anesthetic Lidocaine: Negative Cooperativity and Half-of-Sites Saturation Kinetics

TWIK-related K+ channel TREK1, a background leak K+ channel, has been strongly implicated as the target of several general and local anesthetics. Here, using the whole-cell and single-channel patch-clamp technique, we investigated the effect of lidocaine, a local anesthetic, on the human (h) TREK1 channel heterologously expressed in human embryonic kidney 293 cells by an adenoviral-mediated expression system. Lidocaine, at clinical concentrations, produced reversible, concentration-dependent inhibition of hTREK1 current, with IC50 value of 180 mu M, by reducing the single-channel open probability and stabilizing the closed state. We have identified a strategically placed unique aromatic couplet (Tyr352 and Phe355) in the vicinity of the protein kinase A phosphorylation site, Ser348, in the C-terminal domain (CTD) of hTREK1, that is critical for the action of lidocaine. Furthermore, the phosphorylation state of Ser348 was found to have a regulatory role in lidocaine-mediated inhibition of hTREK1. It is interesting that we observed strong intersubunit negative cooperativity (Hill coefficient = 0.49) and half-of-sites saturation binding stoichiometry (half-reaction order) for the binding of lidocaine to hTREK1. Studies with the heterodimer of wild-type (wt)-hTREK1 and Delta 119 C-terminal deletion mutant (hTREK1(wt)-Delta 119) revealed that single CTD of hTREK1 was capable of mediating partial inhibition by lidocaine, but complete inhibition necessitates the cooperative interaction between both the CTDs upon binding of lidocaine. Based on our observations, we propose a model that explains the unique kinetics and provides a plausible paradigm for the inhibitory action of lidocaine on hTREK1.

Chapter 1: Precarious creativity: Global media, local labor

In most parts of the world, screen media workers—actors, directors, gaffers, and makeup artists—consider Hollywood to be glamorous and aspirational. If given the opportunity to work on a major studio lot, many would make the move, believing the standards of professionalism are high and the history of accomplishment is renowned. Moreover, as a global leader, Hollywood offers the chance to rub shoulders with talented counterparts and network with an elite labor force that earns top-tier pay and benefits. Yet despite this reputation, veterans say the view from inside isn’t so rosy, that working conditions have been deteriorating since the 1990s if not earlier. This grim outlook is supported by industry statistics that show the number of good jobs has been shrinking as studios outsource production to Atlanta, London, and Budapest, among others...

Causes and consequences of inbreeding in the ant Formica exsecta

Human actions cause destruction and fragmentation of natural habitats, predisposing populations to loss of genetic diversity and inbreeding, which may further decrease their fitness and survival. Understanding these processes is a main concern in conservation genetics. Yet data from natural populations is scarce, particularly on invertebrates, owing to difficulties in measuring both fitness and inbreeding in the wild. Ants are social insects, and a prime example of an ecologically important group for which the effects of inbreeding remain largely unstudied. Social insects serve key roles in all terrestrial ecosystems, and the division of labor between the females in the colonies queens reproduce, workers tend to the developing brood probably is central to their ecological success. Sociality also has important implications for the effects of inbreeding. Despite their relative abundance, the effective population sizes of social insects tend to be small, owing to the low numbers of reproductive individuals relative to the numbers of sterile workers. This may subject social insects to loss of genetic diversity and subsequent inbreeding depression. Moreover, both the workers and queens can be inbred, with different and possibly multiplicative consequences. The aim of this study was to investigate causes and consequences of inbreeding in a natural population of ants. I used a combination of long-term field and genetic data from colonies of the narrow-headed ant Formica exsecta to examine dispersal, mating behavior and the occurrence of inbreeding, and its consequences on individual and colony traits. Mating in this species takes place in nuptial flights that have been assumed to be population-wide and panmictic. My results, however, show that dispersal is local, with queens establishing new colonies as close as 60 meters from their natal colony. Even though actual sib-mating was rare, individuals from different but related colonies pair, which causes the population to be inbred. Furthermore, multiple mates of queens were related to each other, which also indicates localized mating flights. Hence, known mechanisms of inbreeding avoidance, dispersal and multiple mating, were not effective in this population, as neither reduced inbreeding level of the future colony. Inbreeding had negative consequences both at the individual and colony level. A queen that has mated with a related male produces inbred workers, which impairs the colony s reproductive success. The inbred colonies were less productive and, specifically, produced fewer new queens, possibly owing to effects of inbreeding on the caste determination of female larvae. A striking finding was that males raised in colonies with inbred workers were smaller, which reflects an effect of the social environment as males, being haploid, cannot be inbred themselves. The queens produced in the inbred colonies, in contrast, were not smaller, but their immune response was up-regulated. Inbreeding had no effect on queen dispersal, but inbred queens had a lower probability of successfully founding a new colony. Ultimately, queens that survived through the colony founding phase had a shorter lifespan. This supports the idea that inbreeding imposes a genetic stress, leading to inbreeding depression on both the queen and the colony level. My results show that inbreeding can have profound consequences on insects in the wild, and that in social species the effects of inbreeding may be multiplicative and mediated through the diversity of the social environment, as well as the genetic makeup of the individuals themselves. This emphasizes the need to take into account all levels of organization when assessing the effects of genetic diversity in social animals.

On the computation of two-dimensional compressible flow fields by the modified local stability scheme

The modified local stability scheme is applied to several two-dimensional problems—blunt body flow, regular reflection of a shock and lambda shock. The resolution of the flow features obtained by the modified local stability scheme is found to be better than that achieved by the other first order schemes and almost identical to that achieved by the second order schemes incorporating artificial viscosity. The scheme is easy for coding, consumes moderate amount of computer storage and time. The scheme can be advantageously used in place of second order schemes.