Social Capital and Self-rated Health: testing association with longitudinal and multilevel methodologies

Since Durkheim’s seminal work over a century ago, research has repeatedly shown that individuals with higher levels of social integration, social networks and social support have better health status. However, the recent introduction of a contextual phenomenon known as social capital to the field of public health has sparked lively debate as to how it may also influence the health of individuals, if at all. Though critics have raised several points of contention regarding reported association between social capital and health over recent years, one outstanding issue remains: the lack of empirical research focusing on causal relationships, due to paucity of adequate longitudinal social capital data. The overall aim of this thesis is to test association between different social capital proxies and self-rated health (SRH), alongside other well-known health determinants, using multilevel and longitudinal data, whilst employing a variety of study designs and methods. All data used in this thesis come from the United Kingdom’s British Household Panel Survey (BHPS) from years 2000, 03, 05, 07 and 08. The underlying premise of this body of work is to investigate temporal (causal) relationships between social capital and health. All four papers of this thesis demonstrate that generalised trust is the most robust of all social capital proxies tested, it maintaining a positive association with SRH over time. Furthermore, results from paper III imply that prior trust levels can predict future SRH, lending weight to the hypothesis that trust is an independent determinant of health. However, debate remains as to whether generalised trust solely captures social capital or other, more tangible aspects of social cohesion

Network Traffic Processing with PFQ

This paper presents Packet Family Queue (PFQ), a high-performance framework for packet processing designed to flexibly handle network applications parallelism and making traffic processing safe and easy. PFQ is an open-source module for the Linux kernel that combines software-accelerated packet I/O to in-kernel early stage packet processing and fine-grained distribution to network applications and physical devices. PFQ does not require any modification to network device drivers and exposes programming interfaces to multi-threaded applications natively designed to run on top of it, as well as to legacy monitoring tools using the pcap library. The results show that the flexibility and the backward compatibility provided by PFQ do not impact its processing performance that, in fact, reaches line rate figures in the cases of pure speed tests and real practical monitoring use cases on 10+ Gb/s links

An In Situ Surface-Enhanced Infrared Absorption Spectroscopy Study of Electrochemical CO2 Reduction: Selectivity Dependence on Surface C-Bound and O-Bound Reaction Intermediates

The CO_{2} electro-reduction reaction (CORR) is a promising avenue to convert greenhouse gases into high-value fuels and chemicals, in addition to being an attractive method for storing intermittent renewable energy. Although polycrystalline Cu surfaces have long known to be unique in their capabilities of catalyzing the conversion of CO_{2} to higher-order C1 and C2 fuels, such as hydrocarbons (CH_{4}, C_{2}H_{4} etc.) and alcohols (CH_{3}OH, C_{2}H_{5}OH), product selectivity remains a challenge. In this study, we select three metal catalysts (Pt, Au, Cu) and apply in situ surface enhanced infrared absorption spectroscopy (SEIRAS) and ambient-pressure X-ray photoelectron spectroscopy (APXPS), coupled to density-functional theory (DFT) calculations, to get insight into the reaction pathway for the CORR. We present a comprehensive reaction mechanism for the CORR, and show that the preferential reaction pathway can be rationalized in terms of metal-carbon (M-C) and metal-oxygen (M-O) affinity. We show that the final products are determined by the configuration of the initial intermediates, C-bound and O-bound, which can be obtained from CO_{2} and (H)CO_{3}, respectively. C1 hydrocarbons are produced via OCH_{3, ad} intermediates obtained from O-bound CO_{3, ad} and require a catalyst with relatively high affinity for O-bound intermediates. Additionally, C2 hydrocarbon formation is suggested to result from the C-C coupling between C-bound CO_{ad} and (H)CO_{ad}, which requires an optimal affinity for the C-bound species, so that (H)CO_{ad} can be further reduced without poisoning the catalyst surface. Our findings pave the way towards a design strategy for CORR catalysts with improved selectivity, based on this experimental/theoretical reaction mechanisms that have been identified

Dactylitis as a first manifestation of arthritis associated with hidradenitis suppurativa

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