Toward an efficient solution for dynamic ad hoc network interoperability

An ad hoc network is formed by an impromptu grouping of network capable nodes. The nodes forming the network have unconstrained mobility, and so provide a dynamic network topology. Current work in this research area has focused on designing routing protocols capable of efficiently forwarding packets in these dynamic network environments. This has led to several designs for ad hoc routing protocols based on various routing algorithms, each suited to specific usage characteristics. This paper will discuss issues relating to routing in ad hoc networks. We will describe an active networking based solution that provides dynamic routing protocol interoperability and enables migration of nodes between ad hoc groups. Our design is motivated by a squad and base scenario which consists of two groups wishing to communicate. These groups have contrasting deployment characteristics and so use different routing protocols

Examining the Effects of Anti-Nogo a Immunotherapy on Post-Stroke Neurogenesis in the Adult Rat

Stroke is a leading cause of adult disability with no pharmacological treatments to restore lost function. Our laboratory has shown that treatment with neutralizing antibodies against the neurite growth-inhibitory protein Nogo-A improves sensorimotor and cognitive recovery after stroke in adult and aged rats. This recovery is paralleled by increased dendritic and axonal plasticity in anti-Nogo-A-treated rats. Neurogenesis, an alternate form of plasticity involving the de novo production of new neurons, may contribute to post-stroke neural repair. While previous studies have found roles for Nogo-A in adult neurogenesis, neurogenesis has not been investigated after stroke and anti-Nogo-A treatment. The goal of these studies was to examine whether anti-Nogo-A antibody treatment potentiated post-stroke neurogenesis in the brain’s two main neurogenic niches, the subventricular zone (SVZ) and dentate gyrus (DG). We first identified that immature neurons, but not stem cells, in the SVZ expressed Nogo-A. However, Nogo-A was not found at the surface of SVZ-derived neuroblasts and accordingly, the motility of SVZ-derived neuroblasts was not altered by anti-Nogo-A antibody treatment in vitro. However, these cells were still susceptible to Nogo-A signaling, as treatment with recombinant Δ20 peptide, one of the inhibitory domains of Nogo-A, led to a modest reduction in neuroblast maximum velocity. After stroke, anti-Nogo-A treatment had no effect on the number of proliferating cells in the SVZ, or on the density of doublecortin-positive neuroblasts, suggesting that anti-Nogo-A treatment does not stimulate neurogenesis in the SVZ after stroke. In the DG, Nogo-A was again found to be expressed by immature neurons, but not neural stem cells. However, as in the SVZ, anti-Nogo-A treatment did not affect the number of proliferating neural precursors or the number of new neurons produced after stroke. These results suggest that neurogenesis contributes little to the sensorimotor and cognitive recovery observed after stroke and anti-Nogo-A treatment. Due to its stagespecific expression in immature neurons, Nogo-A is likely to play a role in adult neurogenesis in both the SVZ and DG, but is not targeted by anti-Nogo-A antibody treatment

The political carousel: elite power-sharing, political instability and the allocation of senior government posts in Africa

This research project examines how various political events and factors influence the composition of senior government elites in a range of African states. Using a newly created dataset of African cabinet ministers, this thesis creates a number of metrics to measure elite volatility and ethnic, regional and political representation. These metrics are used to assess leader and regime strategies of elite power-sharing. It then employs a range of quantitative and qualitative methods to investigate how factors such as ethnic demography, regime strength, economic performance, opposition cohesion and popular unrest influence these metrics. Through this process the thesis aims to demonstrate how the distribution of political power within a state can be estimated by allocation and reshuffling of cabinet ministers. This research project contributes a number of key findings. Firstly, most regimes represent the majority relevant subnational groups within the senior government, but that representation is unbalanced with certain groups being overrepresented and others underrepresented. Secondly, these imbalances and variation in which groups are favoured provide information on the distribution of political power. Thirdly, that different political environments lend themselves to different compositions in the senior government and different strategies of elite power-sharing. In the same vein, individual political events which alter the balance of power are accompanied with corresponding changes in senior government which reflect these shifts in the political hierarchy. These findings contribute to the debates on the determinants of African political power distributions, elite designations and processes, formal vs informal institutions and the political survival literature. A broad benefit of this work is to demonstrate the variance in power sharing arrangements across the African continent. Furthermore, this project demonstrates that external events change leader and elite calculations, which in turn changes strategies of power sharing

Ethnic identity, political identity and ethnic conflict: simulating the effect of congruence between the two identities on ethnic violence and conflict

This thesis outlines and presents an alternative hypothetical process to the emergence of ethnic conflict. Ethnic conflicts, rather than being dependent upon pre-existing 'ancient hatreds', are instead the result of a congruence between ethnic and political identity which grants individuals the ability to use ethnicity to identify and eliminate political threats. This hypothesis is formed by the examination of three case studies of ethnic conflict: Lebanon, Northern Ireland and Croatia. This hypothesis is then formalised and tested using an agent based simulation in which agent interactions are dependent upon ethnic and political identity and the congruence between the two. As predicted there was a strong positive correlation between how accurately ethnic identity reflected political identity and the level of ethnically motivated violence in the simulation, although the relationship was not linear. Furthermore the effect of a shift in congruence was found to be roughly comparable to the effect of initialising agents with a moderate level of pre-existing ethnic antagonism

The Political Carousel

"This research project examines how various political events and factors influence the composition of senior government elites in a range of African states. Using a newly created dataset of African cabinet ministers, this thesis creates a number of metrics to measure elite volatility and ethnic, regional and political representation. These metrics are used to assess leader and regime strategies of elite power-sharing. It then employs a range of quantitative and qualitative methods to investigate how factors such as ethnic demography, regime strength, economic performance, opposition cohesion and popular unrest influence these metrics. Through this process the thesis aims to demonstrate how the distribution of political power within a state can be estimated by allocation and reshuffling of cabinet ministers. This research project contributes a number of key findings. Firstly, most regimes represent the majority relevant subnational groups within the senior government, but that representation is unbalanced with certain groups being overrepresented and others underrepresented. Secondly, these imbalances and variation in which groups are favoured provide information on the distribution of political power. Thirdly, that different political environments lend themselves to different compositions in the senior government and different strategies of elite power-sharing. In the same vein, individual political events which alter the balance of power are accompanied with corresponding changes in senior government which reflect these shifts in the political hierarchy. These findings contribute to the debates on the determinants of African political power distributions, elite designations and processes, formal vs informal institutions and the political survival literature. A broad benefit of this work is to demonstrate the variance in power sharing arrangements across the African continent. Furthermore, this project demonstrates that external events change leader and elite calculations, which in turn changes strategies of power sharing.

Impacts of fuel consumption taxes on mobility patterns and CO2 emissions using a system dynamic approach

Current transport behaviour leads to increasing congestion of the infrastructure, growing dependence on fossil fuels, increasing energy demand, and growing CO2 emissions. Policies based principally on increasing system speed and in particular car speeds will lead to greater urban sprawl with increases in average trip lengths. Time saved by speed increases are traded for more distance. This trend is not sustainable in the longer term. Transport policies based just on time savings for citizens may not be the basis for our city planning strategy. The same happens with transport cost. With underpriced transport, the market undervalues land use location, which again may lead city to sprawl and could induce greater trip lengths. In this study, the efficiency of a fuel consumption or CO2 tax policy is analysed as a policy to internalise externalities of transport in a fair travel cost. Based on system dynamics theory, an integrated land use and transport model is proposed in order to assess the effects and impacts of such policy in the short, medium and long term. Different scenarios related to clean vehicles are incorporated. This model is applied to three cities Madrid, Vienna and Leeds and compares their results

Hospitals and the Web: A Maturing Relationship

How are hospitals using the Internet in marketing today? Where are health care marketers focusing their online efforts?What returns are marketers seeing from their Internet initiatives and investments? These are some of the questions we have been tracking since 1995 when we conducted the first-ever study to examine the ways that hospital marketers around the country were using the Internet and other emerging technology to promote their organizations. In the most recent survey, we look at what health care marketers are doing online and take the pulse of an industry grappling with rapid change and as yet unproven Internet strategies

Health Care Marketing and the Internet

This article presents research on the growing number of health care providers using the Internet as a health care marketing tool in the U.S. The author notes that the Internet is changing the way consumers seek healthcare related information as well as the way it can be provided to them. The results of the study suggest that consumers will increasingly rely on sources like the Internet for information, that health information will be a commodity on the Internet, that the Internet will help build relationships between providers and consumers and that marketers will be expected to develop and manage Internet-related technologies in accompaniment to their organization

Hospital Marketing and the Internet: Revisited

In 1995 a study was conducted to explore the use of the Internet in hospital marketing. Use of the Internet has exploded since that study was published. This manuscript replicates the 1995 study and extends it by investigating several managerial and operational issues concerning the use of the Internet in hospital marketing