Containment and conversion: Urban livelihoods and the circulation of value amid South Africa's avian influenza outbreak.

In South Africa the racialized contours of economic life powerfully shape the distribution of who owns poultry enterprises, who is employed to labor in them, who consumes poultry products, and in which way. When, in late 2017, an outbreak of highly pathogenic avian influenza (H5N8) decimated the South African poultry sector, it revealed the ontological transformations of industrial egg-laying poultry into "cull birds" and then into , the quintessential rural chicken. It thus showed how distinct regimes of value "articulate," blurring infectious and noninfectious concerns as new chains of conversion were inaugurated across domestic and global economies.

An entry risk assessment of African horse sickness virus into the controlled area of South Africa through the legal movement of equids.

South Africa is endemic for African horse sickness (AHS), an important health and trade-sensitive disease of equids. The country is zoned with movement control measures facilitating an AHS-free controlled area in the south-west. Our objective was to quantitatively establish the risk of entry of AHS virus into the AHS controlled area through the legal movement of horses.

Critical Casimir interactions of colloids in micellar critical solutions.

We study the temperature-dependence of critical Casimir interactions in a critical micellar solution of the nonionic surfactant C12E5 dissolved in water. Experimentally, this is achieved with total internal reflection microscopy (TIRM) which measures the interaction between a single particle and a flat wall. For comparison, we also studied the pair interactions of a two dimensional layer of colloidal particles in the identical micellar system which yields good agreement with the TIRM results.

Provincial Veterinary Services respond to drought in South Africa.

In 2018, Cape Town, South Africa, nearly ran out of water. That this has not yet happened is in large part due to the water-saving efforts of its citizens. It is highly likely that this situation will be repeated in Cape Town and that similar situations will be experienced by major cities in other parts of the world.

Human surveillance and phylogeny of highly pathogenic avian influenza A(H5N8) during an outbreak in poultry in South Africa, 2017.

Background: In June 2017, an outbreak of the highly pathogenic avian influenza A(H5N8) was detected in commercial poultry farms in South Africa, which rapidly spread to all nine South African provinces.

Objectives: We conducted active surveillance for the transmission of influenza A(H5N8) to humans working with infected birds during the South African outbreak.

Methods: Influenza A(H5N8)-positive veterinary specimens were used to evaluate the ability of real-time PCR-based assays to detect contemporary avian influenza A(H5N8) strains.

Establishing post-outbreak freedom from African horse sickness virus in South Africa's surveillance zone.

An African horse sickness (AHS) outbreak occurred in South Africa's AHS controlled area in autumn 2016. A freedom from disease survey was performed to establish the likelihood of ongoing circulation of the associated virus during the same period the following year. A single-stage surveillance strategy was employed with a population-level design prevalence of 1% to establish a survey population sensitivity of 95% (probability that one or more positive horses would be detected if AHS was present at a prevalence greater than or equal to the design prevalence).

A field investigation of an African horse sickness outbreak in the controlled area of South Africa in 2016.

An outbreak of African horse sickness (AHS) caused by AHS virus type 1 occurred within the South African AHS surveillance zone during April and May 2016. The index case was detected by a private veterinarian through passive surveillance. There were 21 cases in total, which is relatively low compared to case totals during prior AHS outbreaks in the same region (and of the same AHS virus type) in 2004, 2011 and 2014.

Extrapolation to Nonequilibrium from Coarse-Grained Response Theory.

Nonlinear response theory, in contrast to linear cases, involves (dynamical) details, and this makes application to many-body systems challenging. From the microscopic starting point we obtain an exact response theory for a small number of coarse-grained degrees of freedom. With it, an extrapolation scheme uses near-equilibrium measurements to predict far-from-equilibrium properties (here, second order responses).

Paratuberculosis in a domestic dog in South Africa.

This case report shows that Mycobacterium avium subsp. paratuberculosis (MAP) infection can cause clinical disease in domestic dogs, and should be considered as a differential diagnosis for gastrointestinal inflammatory conditions. A male dachshund presented with lethargy and pain.

Interactions of Colloidal Particles and Droplets with Water-Oil Interfaces Measured by Total Internal Reflection Microscopy.

Total internal reflection microscopy (TIRM) is a well-known technique to measure weak forces between colloidal particles suspended in a liquid and a solid surface by using evanescent light scattering. In contrast to typical TIRM experiments, which are carried out at liquid-solid interfaces, here we extend this method to liquid-liquid interfaces. Exemplarily, we demonstrate this concept by investigating the interactions of micrometer-sized polystyrene particles and oil droplets near a flat water-oil interface for different concentrations of added salt and ionic surfactant (SDS).

Description of an outbreak of highly pathogenic avian influenza in domestic ostriches (Struthio camelus) in South Africa in 2011.

In 2011, the commercial ostrich production industry of South Africa experienced an outbreak of highly pathogenic avian influenza (HPAI), subtype H5N2. Surveillance using antibody and antigen detection revealed 42 infected farms with a between-farm prevalence in the affected area of 16%. The outbreak was controlled using depopulation of infected farms, resulting in the direct loss of 10% of the country's domestic ostrich population.

The prevalence of antibodies to Toxoplasma gondii in sheep in the Western Cape, South Africa.

The seroprevalence of Toxoplasma gondii antibodies in a sample of 292 merino sheep farmed in a semi-intensive manner in the Overberg region of the Western Cape, South Africa, was investigated. Antibody seroprevalence was determined by enzyme-linked immunosorbent assay. Of the total sample, 23 sheep tested positive for T.

Direct measurement of thermophoretic forces.

We study the thermophoretic motion of a micron sized single colloidal particle in front of a flat wall by evanescent light scattering. To quantify thermophoretic effects we analyse the nonequilibrium steady state (NESS) of the particle in a constant temperature gradient perpendicular to the confining walls. We propose to determine thermophoretic forces from a "generalized potential" associated with the probability distribution of the particle position in the NESS.

A life course approach to cardiovascular disease prevention.

During the past 2 decades, life-course social-ecological frameworks have emerged across health, developmental, social, behavioral, and public health disciplines as useful models for explaining how health trajectories develop over an individual's lifetime and how this knowledge can guide and inform new approaches to clinical and public health practice, multilevel policies, and research. Viewed from this perspective, and with emphasis on global cardiovascular health promotion and prevention of cardiovascular disease (CVD), this article summarizes evidence on the early origins and progression of CVD processes across the life course of individuals and diverse populations. Current evidence-based guidelines for CVD prevention are summarized, and recommendations for future research are suggested.

A life course approach to cardiovascular disease prevention.

During the past 2 decades, life-course social-ecological frameworks have emerged across health, developmental, social, behavioral, and public health disciplines as useful models for explaining how health trajectories develop over an individual's lifetime and how this knowledge can guide and inform new approaches to clinical and public health practice, multilevel policies, and research. Viewed from this perspective, and with emphasis on global cardiovascular health promotion and prevention of cardiovascular disease (CVD), this article summarizes evidence on the early origins and progression of CVD processes across the life course of individuals and diverse populations. Current evidence-based guidelines for CVD prevention are summarized, and recommendations for future research are suggested.

Force measurement in the presence of Brownian noise: equilibrium-distribution method versus drift method.

The study of microsystems and the development of nanotechnologies require alternative techniques to measure piconewton and femtonewton forces at microscopic and nanoscopic scales. Among the challenges is the need to deal with the ineluctable thermal noise, which, in the typical experimental situation of a spatial diffusion gradient, causes a spurious drift. This leads to a correction term when forces are estimated from drift measurements [G.

Archimedean-like colloidal tilings on substrates with decagonal and tetradecagonal symmetry.

Two-dimensional colloidal suspensions subjected to laser interference patterns with decagonal symmetry can form an Archimedean-like tiling phase where rows of squares and triangles order aperiodically along one direction (J. Mikhael et al., Nature 454, 501 (2008)).

Influence of noise on force measurements.

We demonstrate how the ineluctable presence of thermal noise alters the measurement of forces acting on microscopic and nanoscopic objects. We quantify this effect exemplarily for a Brownian particle near a wall subjected to gravitational and electrostatic forces. Our results demonstrate that the force-measurement process is prone to artifacts if the noise is not correctly taken into account.

Critical Casimir effect in classical binary liquid mixtures.

If a fluctuating medium is confined, the ensuing perturbation of its fluctuation spectrum generates Casimir-like effective forces acting on its confining surfaces. Near a continuous phase transition of such a medium the corresponding order parameter fluctuations occur on all length scales and therefore close to the critical point this effect acquires a universal character, i.e.

Novel perspectives for the application of total internal reflection microscopy.

Total Internal Reflection Microscopy (TIRM) is a sensitive non-invasive technique to measure the interaction potentials between a colloidal particle and a wall with femtonewton resolution. The equilibrium distribution of the particle-wall separation distance z is sampled monitoring the intensity I scattered by the Brownian particle under evanescent illumination. Central to the data analysis is the knowledge of the relation between I and the corresponding z, which typically must be known a priori.

Critical Casimir forces in colloidal suspensions on chemically patterned surfaces.

We investigate the behavior of colloidal particles immersed in a binary liquid mixture of water and 2,6-lutidine in the presence of a chemically patterned substrate. Close to the critical point of the mixture, the particles are subjected to critical Casimir interactions with force components normal and parallel to the surface. Because the strength and sign of these interactions can be tuned by variations in the surface properties and the mixtures temperature, critical Casimir forces allow the formation of highly ordered monolayers but also extend the use of colloids as model systems.

Archimedean-like tiling on decagonal quasicrystalline surfaces.

Monolayers on crystalline surfaces often form complex structures with physical and chemical properties that differ strongly from those of their bulk phases. Such hetero-epitactic overlayers are currently used in nanotechnology and understanding their growth mechanism is important for the development of new materials and devices. In comparison with crystals, quasicrystalline surfaces exhibit much larger structural and chemical complexity leading, for example, to unusual frictional, catalytical or optical properties.

Direct measurement of critical Casimir forces.

When fluctuating fields are confined between two surfaces, long-range forces arise. A famous example is the quantum-electrodynamical Casimir force that results from zero-point vacuum fluctuations confined between two conducting metal plates. A thermodynamic analogue is the critical Casimir force: it acts between surfaces immersed in a binary liquid mixture close to its critical point and arises from the confinement of concentration fluctuations within the thin film of fluid separating the surfaces.

Experimental verification of an exact evanescent light scattering model for TIRM.

Total internal reflection microscopy (TIRM) is a method for the precise measurement of interaction potentials between a spherical colloidal particle and a wall. The method is based on single-particle evanescent wave light scattering. The well-established model used to interpret TIRM data is based on an exponential relation between scattering intensity and particle wall distance.