Free surface flows with large slopes: beyond lubrication theory

The description of free surface flows can often be simplified to thin film (or lubrication) equations, when the slopes of the liquid-gas interface are small. Here we present a long wavelength theory that remains fully quantitative for steep interface slopes, by expanding about Stokes flow in a wedge. For small capillary numbers, the variations of the interface slope are slow and can be treated perturbatively. This geometry occurs naturally for flows with contact lines: we quantify the difference with ordinary lubrication theory through a numerical example and analytically recover the full Cox-Voinov asymptotic solution.Comment: 4 pages, 3 figure

Applying next generation sequencing of genomes and transcriptomes to investigate the population structure and biology of Plasmodium species

Plasmodium parasites, the causative agents of malaria, are responsible for a significant burden of disease worldwide. Understanding populations and parasite biology is critical to developing effective control mechanisms and questions relating to these have been addressed in this thesis using whole genome and transcriptome sequencing. In Southeast Asia, the zoonotic species Plasmodium knowlesi now causes a significant amount of malarial disease, particularly in Malaysia. Clinical isolates of P. knowlesi from peninsular Malaysia were whole genome sequenced and single nucleotide polymorphisms were used to inform population genomic analyses. This work confirmed the existence of a third, divergent population of P. knowlesi in peninsular Malaysia and uncovered evidence of selection acting on these parasites. In sub-Saharan Africa, P. falciparum is responsible for virtually all malarial disease. Clinical isolates sampled from West Africa were investigated using whole transcriptome sequencing of ex vivo parasites, focusing on a gene known as mspdbl2, which is a possible marker of gametocytogenesis. Schizonts from clinical isolates were assessed for MSPDBL2 expression by immunofluorescence assays and were whole transcriptome sequenced. Analysis of gene expression was carried out correlating to expression of MSPDBL2, revealing enrichment of genes with known or suspected involvement in gametocytogenesis. A limiting factor of this investigation was the very low amount of material available from ex vivo culture. An alternative avenue for investigating limiting material is through single-cell sequencing. One method for single-cell transcriptomics was trialled in this thesis and extensive optimisation resulted in the sequencing of transcriptomes from a small number of P. falciparum schizonts, offering a future methodology for investigating gene expression using very few parasites

Network Lasso: Clustering and Optimization in Large Graphs

Convex optimization is an essential tool for modern data analysis, as it provides a framework to formulate and solve many problems in machine learning and data mining. However, general convex optimization solvers do not scale well, and scalable solvers are often specialized to only work on a narrow class of problems. Therefore, there is a need for simple, scalable algorithms that can solve many common optimization problems. In this paper, we introduce the \emph{network lasso}, a generalization of the group lasso to a network setting that allows for simultaneous clustering and optimization on graphs. We develop an algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in a distributed and scalable manner, which allows for guaranteed global convergence even on large graphs. We also examine a non-convex extension of this approach. We then demonstrate that many types of problems can be expressed in our framework. We focus on three in particular - binary classification, predicting housing prices, and event detection in time series data - comparing the network lasso to baseline approaches and showing that it is both a fast and accurate method of solving large optimization problems

Integrating visual and tactile information in the perirhinal cortex

By virtue of its widespread afferent projections, perirhinal cortex is thought to bind polymodal information into abstract object-level representations. Consistent with this proposal, deficits in cross-modal integration have been reported after perirhinal lesions in nonhuman primates. It is therefore surprising that imaging studies of humans have not observed perirhinal activation during visual–tactile object matching. Critically, however, these studies did not differentiate between congruent and incongruent trials. This is important because successful integration can only occur when polymodal information indicates a single object (congruent) rather than different objects (incongruent). We scanned neurologically intact individuals using functional magnetic resonance imaging (fMRI) while they matched shapes. We found higher perirhinal activation bilaterally for cross-modal (visual–tactile) than unimodal (visual–visual or tactile–tactile) matching, but only when visual and tactile attributes were congruent. Our results demonstrate that the human perirhinal cortex is involved in cross-modal, visual–tactile, integration and, thus, indicate a functional homology between human and monkey perirhinal cortices

Modeling Virus Transport and Removal during Storage and Recovery in Heterogeneous Aquifers

A quantitative understanding of virus removal during aquifer storage and recovery (ASR) in physically and geochemically heterogeneous aquifers is needed to accurately assess human health risks from viral infections. A two-dimensional axisymmetric numerical model incorporating processes of virus attachment, detachment, and inactivation in aqueous and solid phases was developed to systematically evaluate the virus removal performance of ASR schemes. Physical heterogeneity was considered as either layered or randomly distributed hydraulic conductivities (with selected variance and horizontal correlation length). Geochemical heterogeneity in the aquifer was accounted for using Colloid Filtration Theory to predict the spatial distribution of attachment rate coefficient. Simulation results demonstrate that the combined effects of aquifer physical heterogeneity and spatial variability of attachment rate resulted in higher virus concentrations in the recovered water at the ASR well (i.e. reduced virus removal). While the sticking efficiency of viruses to aquifer sediments was found to significantly influence virus concentration in the recovered water, the solid phase inactivation under realistic field conditions combined with the duration of storage phase had a predominant influence on the overall virus removal. The relative importance of physical heterogeneity increased under physicochemical conditions that reduced virus removal (e.g. lower value of sticking efficiency or solid phase inactivation rate). This study provides valuable insight on site selection of ASR projects and an approach to optimize ASR operational parameters (e.g. storage time) for virus removal and to minimize costs associated with post-recovery treatment

The Potential For UK Portfolio Investors To Finance Sustainable Tropical Forestry

Environmental Economics and Policy, Resource /Energy Economics and Policy,

Chlamydia trachomatis and the risk of spontaneous preterm birth, babies who are born small for gestational age, and stillbirth: A population-based cohort study

Background: Chlamydia trachomatis is one of the most commonly diagnosed sexually transmitted infections worldwide, but reports in the medical literature of an association between genital chlamydia infection and adverse obstetric outcomes are inconsistent. Methods: The Western Australia Data Linkage Branch created a cohort of women of reproductive age by linking records of birth registrations with the electoral roll for women in Western Australia who were born from 1974 to 1995. The cohort was then linked to both chlamydia testing records and the state perinatal registry for data on preterm births and other adverse obstetric outcomes. We determined associations between chlamydia testing, test positivity, and adverse obstetric outcomes using multivariate logistic regression analyses. Findings: From 2001 to 2012, 101558 women aged 15 to 38 years had a singleton birth. Of these women, 3921 (3·9%) had a spontaneous preterm birth, 9762 (9·6% of 101371 women with available data) had a baby who was small for gestational age, and 682 (0·7%) had a stillbirth. During their pregnancy, 21267 (20·9%) of these women had at least one chlamydia test record, and 1365 (6·4%) of those tested were positive. Before pregnancy, 19157 (18·9%) of these women were tested for chlamydia, of whom 1595 (8·3%) tested positive for chlamydia. Among all women with a test record, after adjusting for age, ethnicity, maternal smoking, and history of other infections, we found no significant association between a positive test for chlamydia and spontaneous preterm birth (adjusted odds ratio 1·08 [95% CI 0·91–1·28]; p=0·37), a baby who was small for gestational age (0·95 [0·85–1·07]; p=0·39), or stillbirth (0·93 [0·61–1·42]; p=0·74). Interpretation: A genital chlamydia infection that is diagnosed and, presumably, treated either during or before pregnancy does not substantially increase a woman’s risk of having a spontaneous preterm birth, having a baby who is small for gestational age, or having a stillbirth. Funding: Australian National Health and Medical Research Counci

The theory of planned behaviour, self-identity, and moral disengagement: what predicts sustainability at work?

Objectives: On the occasion of the Green Impact sustainability initiative at our university, we sought to identify predictors of sustainability-related behaviours (recycling, energy saving and sustainable transport choices) among staff. Design: A quantitative on-line survey was conducted among university staff. In line with the theory of planned behaviour (TPB), we measured intentions (to recycle, to save energy, and to choose sustainable transport), attitudes, subjective norm, and perceived control. Self-identity was added as a popular extension to the TPB. Additionally, we took one of the first measurements of moral disengagement in a sustainability-related study. Methods: All staff participating in the initiative were contacted, 130 responses were received. Correlational methods were used to analyse the survey data. Results: The TPB was broadly supported; however, perceived control was not significant in predicting recycling intentions, subjective norm did not contribute to the prediction of energy saving intentions, and attitude did not predict transport intentions. Self-identity, conversely, made a substantial additional contribution for all target behaviours. The moral disengagement measures were all correlated with sustainability intentions, but there were multicollinearity issues with the TPB variables and between sub-scales. Conclusions: The TPB is useful in predicting workplace sustainability intentions, but different predictors apply to different behaviours. Moral disengagement is another useful explanatory concept, but difficult to incorporate in the TPB. The consistently significant contribution of self-identity suggests that sustainability at work can be promoted by making staff feel like sustainability champions

NASA PTTI programs: Present and future

Current and future Precise Time and Time Interval (PTTI) programs at the Goddard Space Flight Center (GSFC) and the evolution of frequency and time requirements over past years within the various NASA satellite tracking networks are described. A brief history of the network development is also given

Sustainability in the workplace and the theory of planned behaviour: Norms and identity predict environmentally friendly intentions

Social psychology offers an insightful perspective on the psychological processes underlying sustainability-related intentions and actions, at universities and elsewhere. Ajzen’s theory of planned behaviour (TPB) is a well-supported model, positing that attitudes alone will rarely predict intentions and behaviour accurately. Rather, individuals are sensitive to social norms (the perceived requirements of a setting and/or a group to which the actor belongs) and perceived control (the sense that the actor is capable of the behaviour and the environment offers the opportunity). Recently, it has been suggested to include self-identity (the notion that the behaviour is part of who you are). This paper summarises previous research linking the TPB to sustainability, and then reports a quantitative survey of 130 staff members at Canterbury Christ Church University. An online questionnaire measured attitudes, social norms, perceived control, self-identity, and intentions relating to office waste recycling, energy saving, and transport choice. Overall, only self-identity and norms reliably predicted intentions to act in environmentally sustainable ways. Follow-up analyses suggest that different predictors were significant for different intentions, but self-identity always improved prediction over and above the original TPB variables. In conclusion, universities can best cultivate sustainability intentions by promoting favourable norms and self-identities