The small quinolone derived compound HT61 enhances the effect of tobramycin against Pseudomonas aeruginosa in vitro and in vivo.

HT61 is a small quinolone-derived compound previously demonstrated to exhibit bactericidal activity against gram-positive bacteria including methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). When combined with the classical antibiotics and antiseptics neomycin, gentamicin, mupirocin and chlorhexidine, HT61 demonstrated synergistic bactericidal activity against both MSSA and MRSA infections in vitro. In this study, we investigated the individual antimicrobial activity of HT61 alongside its capability to increase the efficacy of tobramycin against both a tobramycin sensitive laboratory reference strain (PAO1) and tobramycin resistant clinical isolates (RP73, NN2) of the gram-negative bacteria Pseudomonas aeruginosa (P. aeruginosa). Using broth microdilution methods, the MICs of HT61 against all strains were assessed, as well as the effect of HT61 in combination with tobramycin using both the chequerboard method and bacterial time-kill assays. A murine model of pulmonary infection was also used to evaluate the combination therapy of tobramycin and HT61 in vivo. In these studies, we demonstrated significant synergism between HT61 and Tobramycin against the tobramycin resistant P. aeruginosa strains RP73 and NN2, whilst an additive/intermediate effect was observed for P. aeruginosa strain PA01 which was further confirmed using bacterial time kill analysis. In addition, the enhancement of tobramycin by HT61 was also evident in in vitro assays of biofilm eradication. Finally, in vivo studies revealed analogous effects to those observed in vitro with HT61 when administered in combination with tobramycin against each of the three P. aeruginosa strains at the highest tested dose (10 mg/kg)

Magnitude and incentives: Revisiting the overweighting of extreme events in risky decisions from experience

Recent experimental evidence in experience-based decision-making suggests that people are more risk seeking in the gains domain relative to the losses domain. This critical result is at odds with the standard reflection effect observed in description-based choice and explained by Prospect Theory. The so-called reversed-reflection effect has been predicated on the extreme-outcome rule, which suggests that memory biases affect risky choice from experience. To test the general plausibility of the rule, we conducted two experiments examining how the magnitude of prospective outcomes impacts risk preferences. We found that while the reversed-reflection effect was present with small-magnitude payoffs, using payoffs of larger magnitude brought participants’ behavior back in line with the standard reflection effect. Our results suggest that risk preferences in experience-based decision-making are not only affected by the relative extremeness but also by the absolute extremeness of past events

Incorporating an iterative energy restraint for the Surface Energy Balance System (SEBS)

© 2017 Elsevier Inc. The Surface Energy Balance System (SEBS) has proven itself as an effective remotely sensed estimator of actual evapotranspiration (ETa). However, it has several vulnerabilities associated with the partitioning of the available energy (AE) at the land surface. We introduce a two stage energy restraint process into the SEBS algorithm (SEBS-ER) to overcome these vulnerabilities. The first offsets the remotely sensed surface temperature to ensure the surface to air temperature difference reflects AE, while the second stage uses a domain based image search process to identify and adjust the proportions of sensible (H) and latent (λE) heat flux with respect to AE. We effectively implemented SEBS-ER over 61 acquisitions over two Landsat tiles (path 90 row 84 and path 91 row 85) in south-eastern Australia that feature heterogeneous land covers. Across the two areas we showed that the SEBS-ER algorithm has: greater resilience to perturbed errors in surface energy balance algorithm inputs; significantly improved accuracy (p < 0.05) at two eddy covariance flux towers in heavily forested (RMSE 62.3 W m− 2, R2 0.879) and sub-alpine grassland (RMSE 33.2 W m− 2, R2 0.939) land covers; and greater temporal stability across 52 daily actual evapotranspiration (ETa) estimates compared to a temporally stable and independent ETa dataset. The energy restraint within SEBS-ER has reduced exposure to the complex errors and uncertainties within remotely sensed, meteorological, and land type SEBS inputs, providing more reliable and accurate spatially distributed ETa products

A multicentre evaluation of emergency abdominal surgery in South Africa: Results from the GlobalSurg-1 South Africa study

Background. GlobalSurg-1 was a multicentre, international, prospective cohort study conducted to address the global lack of surgical outcomes data. Six South African (SA) hospitals participated in the landmark surgical outcomes study. In this subsequent study, we collated the data from these six local participants and hypothesised that the location of surgery was an independent risk factor for an adverse outcome following emergency intraperitoneal surgery.Methods. Participating hospitals contributed 30-day outcomes data of consecutive emergency intraperitoneal surgical operations performed during a 2 week period between July and November 2014. The six heterogeneous hospital cohorts were compared by categorical confounders. The primary outcome measure was in-hospital mortality; secondary outcome measures were in hospital morbidity and length of stay of &gt;14 days. The unadjusted association between hospital and adverse outcome and the univariate association between categorical confounders and adverse outcome were tested. Significant associations were further tested by a multivariate stepwise forward logistic regression model built for each outcome of interest.Results. Six hospitals (designated 1 - 6) contributed outcomes data for 169 operations. The mean age of the patients was 34.9 years (range 9 - 82), 116 (68.6%) were male, and the majority (37.2%) presented as a result of trauma. Hospital 5 was associated with 76-fold increased odds of in-hospital death and 58-fold increased odds of a major in-hospital complication, and hospital 3 was associated with 3-fold increased odds of any in-hospital complication. The final model predicting in-hospital death had a receiver operating characteristic curve statistic of 0.8892.Conclusion. The hospital is an independent risk factor for risk-adjusted adverse outcomes following emergency intraperitoneal surgery in SA

Secure property right as a determinant of SME’s access to formal credit in Ghana: Dynamics between Micro Finance Institutions and Universal Banks

Does registered land title help to improve tenure security and enhance one’s chances of securing a loan from formal financial institutions? This question continues to sharply divide opinions among academics, policy-makers and international development partners. The long running debate on the subject of ‘Property in the Commons’, which serves as the ideological origin of what has become known as ‘Washington Consensus’ in contemporary times claims that there is positive correlation between the possession of registered land title and access to credit. However, this has often received considerable rebuttals. Even if the ‘Washington Consensus’ is accepted, the argument is still laced with some fundamental difficulty because it inherently assumes and treats financial institutions as a homogenous class of business. Yet financial institutions exhibit greater diversity in their operations and decision-making process. This paper attempts to contribute towards developing improved understanding between the ‘secure land title and access to credit relationship’ by disaggregating financial institutions into Micro-finance and Universal Banks (UBs) and examining what role secure land title play in granting credit from the perspectives of these two categories of financial institutions. To achieve this, field level investigations were conducted amongst officials of both Micro-finance Institutions (MFIs) and UBs in Ghana using structured questionnaires. A total of 200 questionnaires – 100 each to MFI and Universal Banks were administered of which a response rate of 51 and 57 was, respectively, achieved. The data were analysed using various non-parametric statistics. The study amongst other things established that UBs and MFIs differ in their opinions on how important secure titles are in the lending process and the nature of the influence they can exert on the final lending decision. It was established that both categories of lenders do regard secure titles as important but whether or not it will influence their decision to accept a given landed property as collateral varies across lender types

Screening for diabetes mellitus in learners residing in the Belhar, Delft and Mfuleni communities of Cape Town, Western Cape, South Africa

Background Historically, children and adolescents have been diagnosed with type 1 diabetes mellitus and it was thought that type 2 diabetes mellitus occurred only in adults. There are increasing reports of type 2 diabetes in children globally, with some as young as eight years old being affected. The average age of diagnosis in this group was 13 years. This has been attributed to the “epidemic” of overweight and obesity currently being observed in both developed and developing countries. There is a paucity of data on the incidence and prevalence of type 2 diabetes mellitus in children compared with that for adults. Most studies reported to date have been clinic based. The few population-based studies that were carried out between 1965 and 1995 have shown a several-fold increase in the incidence rates of type 2 diabetes mellitus. The prevalence of diabetes mellitus in South Africa has risen dramatically in the past two decades, with the highest prevalence rates being found in the adult population of Indian origin, followed by the African, Coloured (mixed ancestry) and White population groups.Objectives This study was undertaken to screen 10 to 16-year-old learners residing in three urban areas of Cape Town, South Africa for diabetes mellitus.Methods Fasting and casual blood glucose levels were measured using a commercial glucometer in 338 randomly selected schoolchildren aged from 10 to 16 from the urban communities of Belhar, Delft and Mfuleni in Cape Town. Early morning urine samples were also tested for the presence of glucose using dipsticks. Anthropometric measurements were carried out using standard procedures. A structured questionnaire on physical activity, demographics and diabetic status was administered to all participants. Overweight and obesity were estimated according to The International Obesity Task Force (IOTF) criteria.Results A total of 15.7% of the learners were overweight and 6.2% were obese; 11.5% of the learners had a first-degree relative with diabetes and 29.9% had a second-degree relative with diabetes. Mean fasting and casual glucose values of 4.26 ± 0.63 mmol/l and 4.58 ± 0.79 mmol/l (pConclusionThese results suggest that population screening of children may not be viable, despite the increase in the prevalence of diabetes mellitus amongst various racial groups in South Africa.For full text, click here: SA Fam Pract 2006;48(6):16-16

Faster k-Medoids Clustering: Improving the PAM, CLARA, and CLARANS Algorithms

Clustering non-Euclidean data is difficult, and one of the most used algorithms besides hierarchical clustering is the popular algorithm Partitioning Around Medoids (PAM), also simply referred to as k-medoids. In Euclidean geometry the mean-as used in k-means-is a good estimator for the cluster center, but this does not hold for arbitrary dissimilarities. PAM uses the medoid instead, the object with the smallest dissimilarity to all others in the cluster. This notion of centrality can be used with any (dis-)similarity, and thus is of high relevance to many domains such as biology that require the use of Jaccard, Gower, or more complex distances. A key issue with PAM is its high run time cost. We propose modifications to the PAM algorithm to achieve an O(k)-fold speedup in the second SWAP phase of the algorithm, but will still find the same results as the original PAM algorithm. If we slightly relax the choice of swaps performed (at comparable quality), we can further accelerate the algorithm by performing up to k swaps in each iteration. With the substantially faster SWAP, we can now also explore alternative strategies for choosing the initial medoids. We also show how the CLARA and CLARANS algorithms benefit from these modifications. It can easily be combined with earlier approaches to use PAM and CLARA on big data (some of which use PAM as a subroutine, hence can immediately benefit from these improvements), where the performance with high k becomes increasingly important. In experiments on real data with k=100, we observed a 200-fold speedup compared to the original PAM SWAP algorithm, making PAM applicable to larger data sets as long as we can afford to compute a distance matrix, and in particular to higher k (at k=2, the new SWAP was only 1.5 times faster, as the speedup is expected to increase with k)

Diagnosis of seeds supply of leafy vegetables in Yaoundé, Cameroon

The traditional leafy vegetables play a major role in the Cameroonian diet. In the metropolitan zone of Yaoundé, these vegetables are produced year round in family and commercial exploitations. The quality of the seeds, their mode of production and their system of distribution are little known. With the aim to better understand the seed system of traditional  vegetables, a study on the supply, the production and the quality of these seeds was carried out. The data were collected using questionnaires on a sample of 133 traditional leafy vegetable producers of the urban and peri-urban zone of Yaoundé. The data were analyzed using SNAP 9  software. The study showed that the most produced species are amaranth (Amaranthus cruentus), nightshade (Solanum scabrum) and jute mallow (Corchorus olitorius). The market-gardeners are influenced in their choice of vegetable to cultivate by the preference of the customers (85.7% of the respondents) and the productivity of the cultivars (66.2% of the  respondents). More than 40% of the respondents buy seeds in the  markets while 7.5% buy seed from other producers and 10.5% in the agricultural inputs stores. About half (47.4%) of the respondents produce seeds by leaving plants in the field after the first or the second harvest while 36.8% of the market-gardeners select the most vigorous plants for seed production. On average, 58.7% of respondents preserve the seeds in hermetically closed bottles and plastic bag. Storage on field is practiced by a significant part of market-gardeners (41.4%). A total of 79.7% of the producers reported constraints with the produced seeds. Poor seed  germination (81.1% of respondents) and the non uniformity of the seed (48.1% of the producers) were reported as the major constraints. The principal source of seed supply in the metropolitan zone of Yaoundé is the self production with rudimentary production and storage techniques subject to many qualitative constraints.Key words: leafy, vegetables, seeds, supply, qualit

Clinical use of HIV integrase inhibitors : a systematic review and meta-analysis

Background: Optimal regimen choice of antiretroviral therapy is essential to achieve long-term clinical success. Integrase inhibitors have swiftly been adopted as part of current antiretroviral regimens. The purpose of this study was to review the evidence for integrase inhibitor use in clinical settings. Methods: MEDLINE and Web-of-Science were screened from April 2006 until November 2012, as were hand-searched scientific meeting proceedings. Multiple reviewers independently screened 1323 citations in duplicate to identify randomized controlled trials, nonrandomized controlled trials and cohort studies on integrase inhibitor use in clinical practice. Independent, duplicate data extraction and quality assessment were conducted. Results: 48 unique studies were included on the use of integrase inhibitors in antiretroviral therapy-naive patients and treatment-experienced patients with either virological failure or switching to integrase inhibitors while virologically suppressed. On the selected studies with comparable outcome measures and indication (n = 16), a meta-analysis was performed based on modified intention-to-treat (mITT), on-treatment (OT) and as-treated (AT) virological outcome data. In therapy-naive patients, favorable odds ratios (OR) for integrase inhibitor-based regimens were observed, (mITT OR 0.71, 95% CI 0.59-0.86). However, integrase inhibitors combined with protease inhibitors only did not result in a significant better virological outcome. Evidence further supported integrase inhibitor use following virological failure (mITT OR 0.27; 95% CI 0.11-0.66), but switching to integrase inhibitors from a high genetic barrier drug during successful treatment was not supported (mITT OR 1.43; 95% CI 0.89-2.31). Integrase inhibitor-based regimens result in similar immunological responses compared to other regimens. A low genetic barrier to drug-resistance development was observed for raltegravir and elvitegravir, but not for dolutegravir. Conclusion: In first-line therapy, integrase inhibitors are superior to other regimens. Integrase inhibitor use after virological failure is supported as well by the meta-analysis. Careful use is however warranted when replacing a high genetic barrier drug in treatment-experienced patients switching successful treatment