Chemical Abundances in Star-Forming Galaxies at High Redshift

A galaxy's metallicity provides a record of star formation, gas accretion, and gas outflow, and is therefore one of the most informative measurements that can be made at high redshift. It is also one of the most difficult. I review methods of determining chemical abundances in distant star-forming galaxies, and summarize results for galaxies at 1<z<3. I then focus on the mass-metallicity relation, its evolution with redshift, and its uses in constraining inflows and outflows of gas, and conclude with a brief discussion of future prospects for metallicity measurements at high redshift.Comment: Invited review to appear in "Chemical Abundances in the Universe: Connecting First Stars to Planets", Proceedings of IAU Symposium 265, Rio de Janeiro 2009, K. Cunha, M. Spite, B. Barbuy, ed

Avian influenza, the wild bird trade and local livelihoods: an interdisciplinary and mixed-methods approach

Emerging infectious diseases (EID) are increasing in frequency with zoonoses originating in wildlife posing the greatest threat to global health. Highly pathogenic avian influenza (HP AI) strain H5N1 is the most expensive and widespread zoonotic disease to emerge recently. First detected in China in 1996, the virus subsequently spread across Asia, Europe, Africa and the Middle East resulting in tens of millions of animal deaths, primarily poultry as well as 329 fatal human cases. This thesis utilises a range of techniques from multiple disciplines to address questions relating to EID epidemiology and control through to the impacts of HPAI H5N1 at the household level within Vietnam. The methodologies employed include adapting an analytical framework to address a public health problem, semi-structured interviews within central Hanoian and rural Vietnamese households, structured questioning, direct surveys of the live bird markets and key-informant interviews. This thesis has identified rapid growth in the trade and exploitation of birds for cultural and recreational human practices within Vietnam which involve several HP AI H5N1- susceptible species and promote ideal conditions for pathogen transmission. We estimate that three million birds annually are extracted from the wild to supply religious merit release practices in Vietnam alone. At the household level, poultry was found to be an important protein source for urban Vietnamese households and kept primarily for consumption by the majority of rural households. We found urban poultry consumers choose to take protective actions to limit direct exposure to HP AI H5N1 whilst rural households choose to persist with the keeping of household poultry flocks despite the potential risks to household health and livelihood stability. We also identify substantial under-reporting of HPAI H5N1 outbreaks to global surveillance databases and consider the implications of this for HPAI H5N1 surveillance programmes. The thesis concludes by bringing together the different aspects of HPAI H5N1's impacts within Vietnam and emphasises the value of multidisciplinary approaches to studying the impacts of EIDs.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Dust obscuration studies along quasar sight lines using simulated galaxies

We use the results of a set of three-dimensional SPH-Treecode simulations which model the formation and early evolution of disk galaxies, including the generation of heavy elements by star formation, to investigate the effects of dust absorption in quasar absorption line systems. Using a simple prescription for the production of dust, we have compared the column density, zinc abundance and optical depth properties of our models to the known properties of Damped Lyman alpha systems. We find that a significant fraction of our model galaxy disks have a higher column density than any observed DLA system. We are also able to show that such parts of the disk tend to be optically thick, implying that any background quasar would be obscured through much of the disk. This would produce the selection effect against the denser absorption systems thought to be present in observations.Comment: 7 pages, 8 figures, to be published in MNRA

Physical activity barriers in the workplace : an exploration of factors contributing to non-participation in a UK workplace physical activity intervention

Purpose– The purpose of this paper is to explore factors contributing to non-participation in a workplace physical activity (PA) intervention in a large UK call centre. Design/methodology/approach – In total, 16 inactive individuals (nine male/seven female), aged 27±9 years, who had not taken part in the intervention were interviewed to explore their perceptions of PA, the intervention and factors which contributed to their non-participation. Transcripts were analysed using thematic analysis. Findings – Six superordinate themes were identified: self-efficacy for exercise; attitudes towards PA; lack of time and energy; facilities and the physical environment; response to the PA programme and PA culture. Barriers occurred at multiple levels of influence, and support the use of ecological or multilevel models to help guide future programme design/delivery. Research limitations/implications – The 16 participants were not selected to be representative of the workplace gender or structure. Future intentions relating to PA participation were not considered and participants may have withheld negative opinions about the workplace or intervention despite use of an external researcher. Practical implications – In this group of employees education about the importance of PA for young adults and providing opportunities to gain social benefits from PA would increase perceived benefits and reduce perceived costs of PA. Workplace cultural norms with respect to PA must also be addressed to create a shift in PA participation. Originality/value – Employees’ reasons for non-participation in workplace interventions remain poorly understood and infrequently studied. The study considers a relatively under-studied population of employed young adults, providing practical recommendations for future interventions

The Chemical Evolution of the Universe I: High Column Density Absorbers

We construct a simple, robust model of the chemical evolution of galaxies from high to low redshift, and apply it to published observations of damped Lyman-alpha quasar absorption line systems (DLAs). The elementary model assumes quiescent star formation and isolated galaxies (no interactions, mergers or gas flows). We consider the influence of dust and chemical gradients in the galaxies, and hence explore the selection effects in quasar surveys. We fit individual DLA systems to predict some observable properties of the absorbing galaxies, and also indicate the expected redshift behaviour of chemical element ratios involving nucleosynthetic time delays. Despite its simplicity, our `monolithic collapse' model gives a good account of the distribution and evolution of the metallicity and column density of DLAs, and of the evolution of the global star formation rate and gas density below redshifts z 3. However, from the comparison of DLA observations with our model, it is clear that star formation rates at higher redshifts (z>3) are enhanced. Galaxy interactions and mergers, and gas flows very probably play a major role.Comment: 36 pages, 11 figures; accepted by MNRA

Oral human papillomavirus (HPV) infection in men who have sex with men: prevalence and lack of anogenital concordance.

To estimate the prevalence of oral detectable human papillomavirus (HPV) DNA in HIV-negative men who have sex with men (MSM) attending a sexual health clinic in London and concordance with anogenital HPV infection. Such data are important to improve our understanding of the epidemiology of oral HPV and the potential use of vaccines to prevent oropharyngeal cancers

A gender strategy for pro-poor climate change mitigation

The Climate Change, Agriculture and Food Security Research Program (CCAFS) of the Consultative Group for International Agricultural Resources (CGIAR) CCAFS “seeks to overcome the threats to agriculture and food security in a changing climate, exploring new ways of helping vulnerable rural communities adjust to global changes in climate.”1 The CCAFS Gender Strategy (Ashby, et al. 2012) makes the case for gender analysis as critical to increased production, improved outcomes for poverty alleviation and increased well-being, and a fairer distribution of burdens and benefits in agriculture among women and men. This report proposes a gender strategy for climate change mitigation and the promotion of low emissions agriculture—the focus of CCAFS Theme 3: Pro-Poor Climate Change Mitigation. Specifically, we provide a strategy for assuring that mitigation efforts meet the goals of poverty alleviation and food security, and do so in ways that benefit poor women materially, personally and socially. We focus on women because of their historical and contemporary disadvantages, and recognize that benefits for women are generally broader and more durable to the extent men embrace those benefits, whether out of their own material interests or from commitments to family and community well-being. Although CCAFS has separated mitigation, adaptation, and risk management into three distinct research themes, we suggest these must be addressed in an integrated way to meet farmers’ needs. Farmers are primarily concerned with their well-being and that of their families and neighbors, rather than larger global environmental issues. Many also hold a ‘landscape-view’ of their home places in which water and energy sources, forests and grasslands, farms and fallows are all considered in relation to one another in contributing to farmers’ livelihood strategies, even though strategies for adaptation may emphasize one part of the landscape and mitigation another (Shames and Scherr, 2011). Initiatives to mitigate greenhouse gas (GHG) emissions should therefore ideally enhance and at least not harm adaptation and risk management. Similarly adaptation should aim to minimize GHG emissions where possible

An annotated key to the nymphs of the families and subfamilies of mayflies

journal articleAttempts to provide keys to the families and subfamilies of Ephemeroptera nymphs in general entomology textbooks (i.e. Essig (1942), Chu (1949), and Brues, Melander and Carpenter (1954)) have been far from satisfactory. This difficulty exists largely because of the failure of specialists of the Ephemeroptera to provide keys of world-wide application that are sufficiently illustrated to be of value to non-specialists. In the last few decades, however, there have been many figures published that will aid any person attempting to construct such keys. Excellent figures of a variety of families are found in such works as those of Barnard (1932), Spieth (1933), Needham, Traver and Hsu (1935), Ulmer (1940), Crass (1947), Berner (1950), Tshernova (1952), and Burks (1953)

Costs and financial benefits of undertaking green building assessments : final report

Construction Industry Institute-Hong Kong Report, no. 15Other Versio

Canton Christian College Ling Naam Hok Hau : its growth and outlook

This publication is the annual report submitted by Charles K. Edmund, President of Canton Christia College for 1918-19, which also bridges the interval since the last President report published in 1912. The contents, mostly used pictorial presentation, provided brief history of the institution from the beginning and a survey of its condition as of 1919. This President\u27s Report was accepted by the Trustees of Canton Christina College on 11 April 1919. Its publication committed to the Secretary of the Board and the President of the College.https://commons.ln.edu.hk/lingnan_history_bks/1007/thumbnail.jp