Egress of non-enveloped enteric RNA viruses

A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some non-enveloped viruses exit cells without inducing cell lysis, while others engage both lytic and non-lytic egress mechanisms. Enteric viruses are transmitted via the faecal-oral route and are important causes of a wide range of human infections, both gastrointestinal and extra-intestinal. Virus cellular egress, when fully understood, may be a relevant target for antiviral therapies, which could minimize the public health impact of these infections. In this review, we outline lytic and non-lytic cell egress mechanisms of non-enveloped enteric RNA viruses belonging to five families: Picornaviridae, Reoviridae, Caliciviridae, Astroviridae and Hepeviridae. We discuss factors that contribute to egress mechanisms and the relevance of these mechanisms to virion stability, infectivity and transmission. Since most data were obtained in traditional two-dimensional cell cultures, we will further attempt to place them into the context of polarized cultures and in vivo pathogenesis. Throughout the review, we highlight numerous knowledge gaps to stimulate future research into the egress mechanisms of these highly prevalent but largely understudied viruses

Quantum dynamics of a model for two Josephson-coupled Bose--Einstein condensates

In this work we investigate the quantum dynamics of a model for two single-mode Bose--Einstein condensates which are coupled via Josephson tunneling. Using direct numerical diagonalisation of the Hamiltonian, we compute the time evolution of the expectation value for the relative particle number across a wide range of couplings. Our analysis shows that the system exhibits rich and complex behaviours varying between harmonic and non-harmonic oscillations, particularly around the threshold coupling between the delocalised and self-trapping phases. We show that these behaviours are dependent on both the initial state of the system as well as regime of the coupling. In addition, a study of the dynamics for the variance of the relative particle number expectation and the entanglement for different initial states is presented in detail.Comment: 15 pages, 8 eps figures, accepted in J. Phys.

A pre-outburst signal in the long-term optical light curve of the recurrent nova RS Ophiuchi

Recurrent novae are binary stars in which a white dwarf accretes matter from a less evolved companion, either a red giant or a main-sequence star. They have dramatic optical brightenings of around 5–6 mag in V in less than a day, several times a century. These occur at variable and unpredictable intervals, and are followed by an optical decline over several weeks and activity from the X-ray to the radio. The unpredictability of recurrent novae and related stellar types can hamper systematic study of their outbursts. Here we analyse the long-term light curve of RS Ophiuchi, a recurrent nova with six confirmed outbursts, most recently in 2006 February. We confirm the previously suspected 1945 outburst, largely obscured in a seasonal gap. We also find a signal via wavelet analysis that can be used to predict an incipient outburst up to a few hundred days before hand. This has never before been possible. In addition, this may suggest that the preferred thermonuclear runaway mechanism for the outbursts will have to be modified, as no pre-outburst signal is anticipated in that case. If our result indeed points to gaps in our understanding of how outbursts are driven, we will need to study such objects carefully to determine if the white dwarf is growing in mass, an essential factor if these systems are to become Type Ia supernovae. Determining the likelihood of recurrent novae being an important source population will have implications for stellar and galaxy evolution

Chaste: a test-driven approach to software development for biological modelling

Chaste (‘Cancer, heart and soft-tissue environment’) is a software library and a set of test suites for computational simulations in the domain of biology. Current functionality has arisen from modelling in the fields of cancer, cardiac physiology and soft-tissue mechanics. It is released under the LGPL 2.1 licence.\ud \ud Chaste has been developed using agile programming methods. The project began in 2005 when it was reasoned that the modelling of a variety of physiological phenomena required both a generic mathematical modelling framework, and a generic computational/simulation framework. The Chaste project evolved from the Integrative Biology (IB) e-Science Project, an inter-institutional project aimed at developing a suitable IT infrastructure to support physiome-level computational modelling, with a primary focus on cardiac and cancer modelling

Nutrient risk assessment in a decision theoretic context

Abstract Background. This study describes a decision-theoretic approach to nutrient assessment based on Bayesian methods, which can be used to give accurate estimates of optimum intakes. Analysis of risk is an incomplete technique for dealing with nutrients and other substances that, by definition, have an associated benefit. Results. This paper shows that the risk analysis methods being developed by the Codex Commission on Nutrition and European Food Safety Authority, among others, are inappropriate for assessing safe nutrient intake levels. Decision theoretic methods incorporate benefits associated with these essential nutrients, as well as potential risk. Conclusion. These methods allow for missing or incomplete data, which conventional risk analysis does not

What does poverty feel like? Urban inequality and the politics of sensation

The emergent field of ‘sensory urbanism’ studies how socio-spatial boundaries are policed through sensorial means. Such studies have tended to focus on either formal policies that seek to control territories and populations through a governance of the senses, or on more everyday micro-politics of exclusion where conflicts are articulated in a sensory form. This article seeks to extend this work by concentrating on contexts where people deliberately seek out sensory experiences that disturb their own physical sense of comfort and belonging. While engagement across lines of sensorial difference may often be antagonistic, we argue for a more nuanced exploration of sense disruption that attends to the complex political potential of sensory urbanism. Specifically, we focus on the politics of sensation in tours of low-income urban areas. Tourists enter these areas to immerse themselves in a different environment, to be moved by urban deprivation and to feel its affective force. What embodied experiences do tourists and residents associate with urban poverty? How do guides mobilise these sensations in tourism encounters, and what is their potential to disrupt established hierarchies of socio-spatial value? Drawing on a collaborative research project in Kingston, Mexico City, New Orleans and Rio de Janeiro, the article explores how tours offer tourists a sense of what poverty feels like. Experiencing these neighbourhoods in an intimate, embodied fashion often allows tourists to feel empathy and solidarity, yet these feelings are balanced by a sense of discomfort and distance, reminding tourists in a visceral way that they do not belong

Rapid Optical Fluctuations in the Black Hole Binary, V4641 Sgr

We report on unprecedented short-term variations detected in the optical flux from the black hole binary system, V4641 Sgr. Amplitudes of the optical fluctuations were larger at longer time scales, and surprisingly reached ~60% around a period of ~10 min. The power spectra of fluctuations are characterized by a power law. It is the first case in black hole binaries that the optical emission was revealed to show short-term and large-amplitude variations given by such a power spectrum. The optical emission from black hole binaries is generally dominated by the emission from the outer portion of an accretion disc. The rapid optical fluctuations however indicate that the emission from an inner accretion region significantly contributes to the optical flux. In this case, cyclo-synchrotron emission associated with various scales of magnetic flares is the most promising mechanism for the violently variable optical emission.Comment: 5 pages, 2 figures, accepted for publication in PAS

Movement 4. Breath sigh tempest: On the temporal dimensions of re‐arrangements

The fourth movement explores the temporal relationship between arrangements and re-arrangements, addressing the question of how an obdurate and ‘sticky’ temporal order may give way to palpable re-arrangement of the ways in which subjects experience time. Eschewing a concern with linear homogenous time, it addresses the processes of re-arrangement by understanding the dynamics of grave events, hauntings of the past, subtly changing rhythms of everyday life, and the force of potential futures in synchrony

Movement 5. Sensing the affective lives of arrangements

This final movement explores whether thinking with re-arrangements can help us account for that which is hidden, unseen or nested in the recesses and folds of urban practices. And if so, how we might then talk about and account for elusive parts of an arrangement that both exert an influence and are influenced. This essay uses sensibilities as an entry point into the intangible interactions between subjects and (re)arrangements