Tomographic imaging and scanning thermal microscopy: thermal impedance tomography

The application of tomographic imaging techniques developed for medical applications to the data provided by the scanning thermal microscope will give access to true three-dimensional information on the thermal properties of materials on a mm length scale. In principle, the technique involves calculating and inverting a sensitivity matrix for a uniform isotropic material, collecting ordered data at several modulation frequencies, and multiplying the inverse of the matrix with the data vector. In practice, inversion of the matrix in impractical, and a novel iterative technique is used. Examples from both simulated and real data are given

Growth and persistence of 17 annual medic (Medicago spp.) accessions on clay soils in central Queensland

Seventeen accessions of annual medics were evaluated on clay soil sites at Emerald, Theodore, Biloela and Mundubbera, central Queensland. Successful medics could have a role in both permanent and ley pastures. However, these are marginal areas for medics with winter (June-August) rainfalls of 80-100 mm. The accessions were selected on the basis of results in southern Queensland, a more favoured area for medics. There were 9 accessions of Medicago truncatula (barrel medic), 4 of M. scutellata (snail medic), 2 of M. polymorpha (burr medic) and 1 each of M. aculeata (keg medic) and M. orbicularis (button medic). Lucerne (M. sativa) cv. Trifecta was sown at 3 sites. All sites except Theodore were irrigated in the year of establishment (1993). The medic seedlings at Theodore died in 1993 and the trial was resown in 1994. Measurements were made of seed set in the first year and whenever it occurred in later years, seedling density in most years and yield when there was adequate growth. Selected measurements were made of soil seed reserves. Measurements ceased in 1998

Why disease due to Mycobacterium tuberculosis is less common than expected in HIV-positive patients in Edinburgh

AbstractBy December 1993, only five cases of tuberculosis were observed in the 1030 HIV-positive patients in Edinburgh, U.K., although, on the basis of historical tuberculin skin test data, between four and eight new cases of tuberculosis were expected per year. Of 310 HIV-positive patients, none of the 19 (6·1%) who were tuberculin skin test positive had developed tuberculosis after 87 months (average) of follow-up. It is suggested that new or re-infection is a more common cause of tuberculosis in HIV-positive patients than reactivation. Restriction fragment length polymorphism typing of Mycobacterium tuberculosis strains could confirm this hypothesis and support currently suggested additional infection control procedures

Amperometric and spectrophotometric determination of carbaryl in natural waters and commercial formulations

The work presented describes the development and evaluation of two flow-injection analysis (FIA) systems for the automated determination of carbaryl in spiked natural waters and commercial formulations. Samples are injected directly into the system where they are subjected to alkaline hydrolysis thus forming 1-naphthol. This product is readily oxidised at a glassy carbon electrode. The electrochemical behaviour of 1-naphthol allows the development of an FIA system with an amperometric detector in which 1-naphthol determination, and thus measurement of carbaryl concentration, can be performed. Linear response over the range 1.0×10–7 to 1.0×10–5 mol L–1, with a sampling rate of 80 samples h–1, was recorded. The detection limit was 1.0×10–8 mol L–1. Another FIA manifold was constructed but this used a colorimetric detector. The methodology was based on the coupling of 1-naphthol with phenylhydrazine hydrochloride to produce a red complex which has maximum absorbance at 495 nm. The response was linear from 1.0×10–5 to 1.5×10–3 mol L–1 with a detection limit of 1.0×10–6 mol L–1. Sample-throughput was about 60 samples h–1. Validation of the results provided by the two FIA methodologies was performed by comparing them with results from a standard HPLC–UV technique. The relative deviation was <5%. Recovery trials were also carried out and the values obtained ranged from 97.0 to 102.0% for both methods. The repeatability (RSD, %) of 12 consecutive injections of one sample was 0.8% and 1.6% for the amperometric and colorimetric systems, respectively

The Effect of Camber Bed Drainage Landforms on Soil Nutrient Distribution and Grain Yield of Maize on the Vertisols of the Accra Plains of Ghana

The Vertisols of the Accra Plains of Ghana are water logged after significant rainfall due to the low-lying topography (0.1-1 %). Camber bed (Cb) drainage landforms have been developed at the Agricultural Research Centre, Kpong, for draining off excess water. Field experiments were conducted to verify if maize growth and yield gradient from the trough to the crest were the result of nutrient gradient or some other factors. Four 5 m and two 10 m Cbs and a 20-m flatland were prepared in a split-split plot design, with landform as main plot, nutrient levels as sub plot and crop row as sub-sub plot. A pot experiment was also carried out for detailed studies. Soil movement brought about a nutrient gradient from the trough of the camber bed to the crest, and also made the soil profile homogeneous. The trough was low in nutrients, compact and prone to water logging, but nutrient levels increased through the middle slope to the crest. The flatland did not have a nutrient gradient but was prone to water logging due to its low-lying nature. Total dry matter (TDM) of maize and grain yield similarly increased from the trough to the crest. Grain yield of maize on the flatland ranged from 2.5–2.6 t ha- 1, while yields on the 5-m Cb were 3.6, 4.2 and 4.8 t ha-1 on the trough, middle slope and crest, respectively. Excess application of 15-15-15 NPK and sulphate of ammonia fertilizers (150% of recommended levels) did not appreciably increase biomass and grain yield in the troughs. However, the maize crop in pots, with soil from the trough, responded positively to fertilizer application, thus confirming that low yield in the trough was the result of both low nutrient availability and the compact subsoil.

South Africa's business process outsourcing services sector: Lessons for Western-based client firms

Since 2008, South Africa has become one of the world's upcoming offshore destinations for business process outsourcing (BPO), a market estimated to be worth $US 182 billion globally by 2013. Western-based client firms evaluating South Africa as a BPO destination must consider the country's relative value against alternative locations. Client firms also have a number of engagement models from which to choose, inclucling outsourcing, erecting a captive centre, or acquiring an existing BPO business. The research finds that, for the UK, US, and Australian client companies in this study, South Africa's value proposition is not just based on costs as other locations are often cheaper. South Africa's value proposition is about overall economic value, high quality service and staff, strong cultural compatibility, and a favourable time zone. The findings reveal that South Africa complements the global portfolio for Western-based client firms that already have BPO centres in Inclia, the Philippines, and Eastern Europe. Moreover, whether client firms build or buy services from South Africa, the research identifies clistinctive risks that need to be mitigated by investing in and effectively governing the business processes performed offshore. Finally, from the case study research, this article identifies management lessons for leveraging South Africa's identifiable BPO service advantage

UK Housing Market: Time Series Processes with Independent and Identically Distributed Residuals

The paper examines whether a univariate data generating process can be identified which explains the data by having residuals that are independent and identically distributed, as verified by the BDS test. The stationary first differenced natural log quarterly house price index is regressed, initially with a constant variance and then with a conditional variance. The only regression function that produces independent and identically distributed standardised residuals is a mean process based on a pure random walk format with Exponential GARCH in mean for the conditional variance. There is an indication of an asymmetric volatility feedback effect but higher frequency data is required to confirm this. There could be scope for forecasting the index but this is tempered by the reduction in the power of the BDS test if there is a non-linear conditional variance process

Norovirus infection results in eIF2α independent host translation shut-off and remodels the G3BP1 interactome evading stress granule formation.

Viral infections impose major stress on the host cell. In response, stress pathways can rapidly deploy defence mechanisms by shutting off the protein synthesis machinery and triggering the accumulation of mRNAs into stress granules to limit the use of energy and nutrients. Because this threatens viral gene expression, viruses need to evade these pathways to propagate. Human norovirus is responsible for gastroenteritis outbreaks worldwide. Here we examined how norovirus interacts with the eIF2α signaling axis controlling translation and stress granules. While norovirus infection represses host cell translation, our mechanistic analyses revealed that eIF2α signaling mediated by the stress kinase GCN2 is uncoupled from translational stalling. Moreover, infection results in a redistribution of the RNA-binding protein G3BP1 to replication complexes and remodelling of its interacting partners, allowing the avoidance from canonical stress granules. These results define novel strategies by which norovirus undergo efficient replication whilst avoiding the host stress response and manipulating the G3BP1 interactome

Antimicrobial resistance and COVID-19: Intersections and implications

Before the coronavirus 2019 (COVID-19) pandemic began, antimicrobial resistance (AMR) was among the top priorities for global public health. Already a complex challenge, AMR now needs to be addressed in a changing healthcare landscape. Here, we analyse how changes due to COVID-19 in terms of antimicrobial usage, infection prevention, and health systems affect the emergence, transmission, and burden of AMR. Increased hand hygiene, decreased international travel, and decreased elective hospital procedures may reduce AMR pathogen selection and spread in the short term. However, the opposite effects may be seen if antibiotics are more widely used as standard healthcare pathways break down. Over 6 months into the COVID-19 pandemic, the dynamics of AMR remain uncertain. We call for the AMR community to keep a global perspective while designing finely tuned surveillance and research to continue to improve our preparedness and response to these intersecting public health challenges