544 research outputs found
SIR epidemics in a population of households
The severity of the outbreak of an infectious disease is highly dependent upon the structure of the population through which it spreads. This thesis considers the stochastic SIR (susceptible infective removed) household epidemic model, in which individuals mix with other individuals in their household at a far higher rate than with any other member of the population. This model gives a more realistic view of dynamics for the transmission of many diseases than the traditional model, in which all individuals in a population mix homogeneously, but retains mathematical tractability, allowing us to draw inferences from disease data.
This thesis considers inference from epidemics using data which has been acquired after an outbreak has finished and whilst it is still in its early, `emerging' phase. An asymptotically unbiased method for estimating within household infectious contact rate(s) from emerging epidemic data is developed as well as hypothesis testing based on final size epidemic data. Finally, we investigate the use of both emerging and final size epidemic data to estimate the vaccination coverage required to prevent a large scale epidemic from occurring. Throughout the thesis we also consider the exact form of the households epidemic model which should be used. Specifically, we consider models in which the level of infectious contact between two individuals in the same household varies according to the size of their household
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Neocuproine-functionalized silica-coated magnetic nanoparticles for extraction of copper(II) from aqueous solution
Neocuproine has been covalently bound to silica-coated maghemite(c-Fe2O3) magnetic nanoparticles (MNPs) by a phenyl ether linkage. The resulting MNPs are able to remove Cu(II) from 12 ppm aqueous solution with an extraction efficiency of up to 99% at pH 2
L’accès des femmes aux emplois supérieurs de la fonction publique : une construction au croisement des itinéraires professionnels et familiaux
À l’initiative de la direction des ressources humaines du ministère de l’équipement, une enquête a été menée auprès des femmes occupant les postes les plus élevés en vue de comprendre le cheminement qui leur a permis d’y parvenir. Cet article s’interroge sur l’accès des femmes aux emplois supérieurs de la fonction publique, en repérant les freins mais aussi les ressources dans lesquelles elles puisent pour surmonter les épreuves rencontrées lors de leur ascension. Il porte une attention particulière aux différents modes de vie conjugale et à leur articulation avec l’engagement professionnel de ces femmes cadres. Enfin, il dresse un panorama des recommandations formulées à l’attention de la DRH tout en questionnant leur mise en œuvre et leur effectivité.Under the auspices of the Human Resources department of the French Ministry of Infrastructure (ministère de l’équipement), a survey was carried out of women in top jobs in order to gain an understanding of the trajectory that allowed them to reach these positions. This article focuses on the access of women to executive positions in the French civil service and identifies the obstacles placed in their way, as well as the resources on which they can draw to surmount the difficulties encountered on the way up the career ladder. In particular, the research focuses on different conjugal arrangements and how these fit with the professional commitments of these female executives. Finally, it presents an overview of the recommendations drawn up for submission to the HR department and analyses their implementation and effectiveness
A transfer-matrix Monte Carlo study of random Penrose tilings
Abstract. We investigate the entropic properties of a simple two-dimensional random quasicrystal model: a random tiling by the 36'and 72'rhombi. Applying the transfer matrix Monte Carla (TMMC) method to random tilings for the first time, we have calculated the entropy as a function of phasan strain. We confirm earlier results that the slate of zero phasan strain (i.e. ten-fold symmetry) has the largest entropy; the entropy is 0.4810 ( 5 ) per tile. In addition, by fitting the dependence ofthe entropy on the pharon strain wedetermined the three stiffness constants in the phason elasticity, one of which is not measurable by previous approaches. We compare the efficacy of the TMMC method with that of other methods
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Adsorption of Pb and Zn from binary metal solutions and in the presence of dissolved organic carbon by DTPA-functionalised, silica-coated magnetic nanoparticles
The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L-1 Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0.025 mmol L-1) on the adsorption of variable concentrations (0 - 0.045 mmol L-1) of the other metal (Pb or Zn, respectively) adsorption was well modelled by linear isotherms (R2>0.60; p≤0.001) and Pb was preferentially adsorbed relative to Zn. In dissolved organic carbon experiments, the presence of fulvic acid (0, 2.1 and 21 mg DOC L-1) reduced Pb and Zn adsorption from 0.01, 0.1 and 1.0 mmol L-1 solutions. However, even at 21 mg DOC L-1 fulvic acid, extraction efficiencies from 0.01 and 0.1 mmol L-1 solutions remained >80% (Pb) and > 50% (Zn). Decreases in extraction efficiency were significant between initial metal concentrations of 0.1 and 1.0 mmol L-1 indicating that at metal loadings between c. 100 mg kg-1 and 300 mg kg-1 occupancy of adsorption sites began to limit further adsorption. The nanoparticles have the potential to perform effectively as metal adsorbents in systems containing more than one metal and dissolved organic carbon at a range of pH values
Genetic analysis of Thai cattle reveals a Southeast Asian indicine ancestry
Cattle commonly raised in Thailand have characteristics of [i]Bos indicus[/i] (zebu). We do not know when or how cattle domestication in Thailand occurred, and so questions remain regarding their origins and relationships to other breeds. We obtained genome-wide SNP genotypic data of 28 bovine individuals sampled from four regions: North (Kho-Khaolampoon), Northeast (Kho-Isaan), Central (Kho-Lan) and South (Kho-Chon) Thailand. These regional varieties have distinctive traits suggestive of breed-like genetic variations. From these data, we confirmed that all four Thai varieties are [i]Bos indicus[/i] and that they are distinct from other indicine breeds. Among these Thai cattle, a distinctive ancestry pattern is apparent, which is the purest within Kho-Chon individuals. This ancestral component is only present outside of Thailand among other indicine breeds in Southeast Asia. From this pattern, we conclude that a unique [i]Bos indicus[/i] ancestor originated in Southeast Asia, and native Kho-Chon Thai cattle retain the signal of this ancestry with limited admixture of other bovine ancestors
Place attachment in deprived neighbourhoods: The impacts of population turnover and social mix
This paper examines the determinants of individual place attachment, focussing in particular on differences between deprived and others neighbourhoods, and on the impacts of population turnover and social mix. It uses a multi-level modelling approach to take account of both individual- and neighbourhood-level determinants. Data are drawn from a large sample government survey, the Citizenship Survey 2005, to which a variety of neighbourhood-level data have been attached. The paper argues that attachment is significantly lower in more deprived neighbourhoods primarily because these areas have weaker social cohesion but that, in other respects, the drivers of attachment are the same. Turnover has modest direct impacts on attachment through its effect on social cohesion. Social mix has very limited impacts on attachment and the effects vary between social groups. In general, higher status or more dominant groups appear less tolerant of social mix
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Exploratory randomised controlled trial of a mindfulness-based weight loss intervention for women
To explore the efficacy of a mindfulness-based weight loss intervention for women. Sixty-two women (ages 19-64; BMI 22.5-52.1) who were attempting to lose weight were randomised to an intervention or control condition. The former were invited to attend four 2-h workshops, the latter were asked to continue with their normal diets. Data were collected at baseline, 4 and 6 months. BMI, physical activity, mental health. At 6 months intervention participants showed significantly greater increases in physical activity compared to controls (p<.05) but no significant differences in weight loss or mental health. However, when intervention participants who reported 'never' applying the workshop principles at 6 months (n=7) were excluded, results showed both significantly greater increases in physical activity (3.1 sessions per week relative to controls, p<.05) and significantly greater reductions in BMI (0.96 relative to controls, equivalent to 2.32 kg, p<0.5). Reductions in BMI were mediated primarily by reductions in binge eating. Despite its brevity, the intervention was successful at bringing about change. Further refinements should increase its efficacy
Engaging with terminology in the multilingual classroom:Teachers’ practices for bridging the gap between L1 lectures and English reading
In some academic settings where English is not the first language it is nonetheless common for reading to be assigned in English, and the expectation is often that students will acquire subject terminology incidentally in the first language as well as in English as a result of listening and reading. It is then a prerequisite that students notice and engage with terminology in both languages. To this end, teachers’ classroom practices for making students attend to and engage with terms are crucial for furthering students’ vocabulary competence in two languages. Using transcribed video recordings of eight undergraduate lectures from two universities in such a setting, this paper provides a comprehensive picture of what teachers ‘do’ with terminology during a lecture, i.e., how terms are allowed to feature in the classroom discourse. It is established, for example, that teachers nearly always employ some sort of emphatic practice when using a term in a lecture. However, the repertoire of such practices is limited. Further, teachers rarely adapt their repertoires to cater to the special needs arguably required in these settings, or to exploit the affordances of multilingual environments
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