Continuous selections of multivalued mappings

This survey covers in our opinion the most important results in the theory of continuous selections of multivalued mappings (approximately) from 2002 through 2012. It extends and continues our previous such survey which appeared in Recent Progress in General Topology, II, which was published in 2002. In comparison, our present survey considers more restricted and specific areas of mathematics. Note that we do not consider the theory of selectors (i.e. continuous choices of elements from subsets of topological spaces) since this topics is covered by another survey in this volume

Metabolomic analyses of Leishmania reveal multiple species differences and large differences in amino acid metabolism

Comparative genomic analyses of Leishmania species have revealed relatively minor heterogeneity amongst recognised housekeeping genes and yet the species cause distinct infections and pathogenesis in their mammalian hosts. To gain greater information on the biochemical variation between species, and insights into possible metabolic mechanisms underpinning visceral and cutaneous leishmaniasis, we have undertaken in this study a comparative analysis of the metabolomes of promastigotes of L. donovani, L. major and L. mexicana. The analysis revealed 64 metabolites with confirmed identity differing 3-fold or more between the cell extracts of species, with 161 putatively identified metabolites differing similarly. Analysis of the media from cultures revealed an at least 3-fold difference in use or excretion of 43 metabolites of confirmed identity and 87 putatively identified metabolites that differed to a similar extent. Strikingly large differences were detected in their extent of amino acid use and metabolism, especially for tryptophan, aspartate, arginine and proline. Major pathways of tryptophan and arginine catabolism were shown to be to indole-3-lactate and arginic acid, respectively, which were excreted. The data presented provide clear evidence on the value of global metabolomic analyses in detecting species-specific metabolic features, thus application of this technology should be a major contributor to gaining greater understanding of how pathogens are adapted to infecting their hosts

The State Socialist Mortality Syndrome

Death rates for working-age men in European state socialist countries deviated from general improvements in survival observed in the rest of Europe during the 20th century. The magnitude of structural labor force changes across countries correlates with lagged increases in death rates for men in the working ages. This pattern is consistent with a hypothesis that hyper-development of heavy industry and stagnation (even contraction) of the service sector created anomic conditions leading to unhealthy lifestyles and self-destructive behavior among men moving from primary-sector to secondary-sector occupations. Occupational contrasts within countries similarly show concentration of rising male death rates among blue collar workers. Collapse of state socialist systems produced rapid corrections in labor force structure after 1990, again correlated with a fading of the state socialist mortality syndrome in following decades

Comparing the effect of various pipe materials on biofilm formation in chlorinated and combined chlorine-chloraminated water systems

To compare the effect of various pipe materials on biofilm formation, surface water was used as the test water source; plastic-based pipe materials (polyvinyl chloride-PVC, unplasticised polyvinyl chloride-UPVC, medium density polyethylene-MDPE) and cement-based pipe materials (cement and asbestos cement) are commonly used in drinking water distribution systems in South Africa as test pipe materials. Disinfection was performed using ca 2.5 mgl-1 initial chlorine followed by ca 1.5mg l-1 monochloramine. The evaluation of the process relied on attached coliforms and heterotrophic plate count bacteria. General data indicated the colonisation of all test pipe materials by micro-organisms under the chlorination process within the first 20 min and over the remainder of the study period. The addition of monochloramine to the chlorinated water system (24 h after chlorination) resulted in the removal of coliforms and heterotrophic bacteria attached to pipe materials. Less than 1 cfuยทcm-2 viable bacterium (except for PVC) was observed on the surface of test pipes between 48 and 168 h. However, the factor of time cannot be ignored in determining the effect of pipe materials on biofilm formation in potable water systems. Bacterial regrowth occurred on the surface of all pipe materials between 168 and 672 h. The capability of bacterial regrowth occurring on the surface of test pipe materials during this period was linked to the depletion of the concentration of monochloramine residual. Statistical evidence showed that the generic type of pipe materials greatly influenced the density of bacteria in laboratory-scale systems. Cement-based materials significantly supported less fixed bacteria than plastic-based materials (at

Safe drinking water still a dream in rural areas of South Africa. Case Study: The Eastern Cape Province

From October to November 2004, and from July to September 2005, a survey of 55 plants was conducted in five District Municipalities (Cacadu, Chris Hani, Amathola, Ukhahlamba and O.R. Tambo) of the Eastern Cape Province, with the aim of examining the disinfection practices used in small rural systems of the Eastern Cape and their effect on the quality of drinking water they supply to the communities.Eighty six percent of the visited plants were treating surface water while 7% were treating groundwater and another 7% were treating both ground- and surface water. The majority of plants surveyed employed some variation of conventional treatment (coagulation, flocculation, sedimentation, filtration, chlorination). Turbidity values in 55% of the plants were within the acceptable SABS limits while the other 45% showed high values. Out of the 55 surveyed plants only 18% complied with the SABS recommended limits in terms of microbiological quality. The major factors that contributed to high bacterial numbers were high turbidity and inefficient chemical (coagulant and chlorine) dosing, which led to low chlorine residuals. It was also noted that although some plants had low bacterial numbers at the point of treatment, bacterial re-growth occurred in the distribution system, thereby compromising the quality of water at the point of use. The worst technical problems encountered tended to be at the newly commissioned or upgraded plants where properly trained operators had yet to be appointed or where the existing staff lack proficiency in the use of the upgraded systems or why certain modifications to the treatment process were being made. Operators were lacking in the required technical knowledge such as flow rate and chemical dosing to effectively execute their duties. Lack of communication between consultants, operators and municipal officials on technical issues relating to plant operation appeared to be a problem. The results of this study gave conclusive evidence that rural water treatment plants are still failing to produce safe drinking water

Potensi Biomassa Rhizoma dan Daun Lamun Kering Thalassia hemprichii yang Terdapat di Pulau Barrang Lompo sebagai Biosorben Ion Logam Cu(II)

Bioma 2(2) 2008Biosorpsi merupakan metode alternatif yang dapat digunakan dalam mengatasi pencemaran lingkungan yang berasal dari buangan limbah yang mengandung polutan logam berat. Biosorpsi ion logam Cu(II) oleh biomassa rhizoma dan daun lamun kering Thalassia hemprichii telah dilakukan pada variasi waktu kontak, pH larutan dan konsentrasi awal ion logam tersebut. Metode yang digunakan adalah metode ???batch??? dan konsentrasi ion logam Cu(II) sebelum dan sesudah biosorpsi diukur dengan spektrofotometer serapan atom (SSA). Kesetimbangan dicapai sesudah 30 menit. Efektivitas adsporpsi bagi ion logam Cu(II) dicapai pada pH 3. Biosorpsi ion Cu(II) dengan menggunakan biomassa rhizoma dan daun lamun Thalassia hemprichii lebih sesuai dengan model isothermal Langmuir dengan nilai kapasitas adsorpsi (Qe) ~ 37 mg/g

Improving the efficiency and sustainability of disinfection at a small rural water treatment plant

The Alice Water Treatment Plant (AWTP) has several operating problems, which often result in poor turbidity removal and inadequate disinfection residual. Some progress has been made in upgrading the skills of plant operators, but the plant performance has failed to improve because of faulty equipment, a shortage of maintenance staff and treatment chemicals that are not delivered in time. The coagulant-dosing pump was found to be malfunctioning for an extended period of time resulting in overdose problems. The self-backwashing filters were no longer backwashing as per design and were producing poor quality filtrate. This in turn increased the chlorine demand and combined with frequent failure of the chlorinators, the plant was producing poor microbiological quality final water. The storage system in the bulk distribution system was investigated and it was found that adequate chlorine residual could be achieved, provided the plant problems were rectified. The difficulties experienced in training and retaining adequately skilled people to run water treatment plants in impoverished rural municipalities have been among the major hurdles to providing acceptable water services in these areas. However a partnership between the Universities and the AWTP came up as a possible solution to these problems. It is therefore recommended that rural municipalities consider this approach and strengthen this relationship, as it played a large role in plant improvement. Water SA Vol. 30 (5) 2005: pp.69-7

Effects of sample preservation methods and duration of storage on the performance of mid-infrared spectroscopy for predicting the age of malaria vectors

Background: Monitoring the biological attributes of mosquitoes is critical for understanding pathogen transmission and estimating the impacts of vector control interventions on the survival of vector species. Infrared spectroscopy and machine learning techniques are increasingly being tested for this purpose and have been proven to accurately predict the age, species, blood-meal sources, and pathogen infections in Anopheles and Aedes mosquitoes. However, as these techniques are still in early-stage implementation, there are no standardized procedures for handling samples prior to the infrared scanning. This study investigated the effects of different preservation methods and storage duration on the performance of mid-infrared spectroscopy for age-grading females of the malaria vector, Anopheles arabiensis. Methods: Laboratory-reared An. arabiensis (N = 3681) were collected at 5 and 17 days post-emergence, killed with ethanol, and then preserved using silica desiccant at 5 °C, freezing at − 20 °C, or absolute ethanol at room temperature. For each preservation method, the mosquitoes were divided into three groups, stored for 1, 4, or 8 weeks, and then scanned using a mid-infrared spectrometer. Supervised machine learning classifiers were trained with the infrared spectra, and the support vector machine (SVM) emerged as the best model for predicting the mosquito ages. Results: The model trained using silica-preserved mosquitoes achieved 95% accuracy when predicting the ages of other silica-preserved mosquitoes, but declined to 72% and 66% when age-classifying mosquitoes preserved using ethanol and freezing, respectively. Prediction accuracies of models trained on samples preserved in ethanol and freezing also reduced when these models were applied to samples preserved by other methods. Similarly, models trained on 1-week stored samples had declining accuracies of 97%, 83%, and 72% when predicting the ages of mosquitoes stored for 1, 4, or 8 weeks respectively. Conclusions: When using mid-infrared spectroscopy and supervised machine learning to age-grade mosquitoes, the highest accuracies are achieved when the training and test samples are preserved in the same way and stored for similar durations. However, when the test and training samples were handled differently, the classification accuracies declined significantly. Protocols for infrared-based entomological studies should therefore emphasize standardized sample-handling procedures and possibly additional statistical procedures such as transfer learning for greater accuracy