Turn-turn short circuit fault management in permanent magnet machines

This paper presents a systematic study on turn-turn short circuit fault and ways to manage them to provide a basis for comparison of the various options available. The possible methods to reduce the likelihood of the winding SC fault and the fault mitigation techniques related to such faults are discussed. A Finite Element (FE) analysis of a surface-mount Permanent Magnet (PM) machine under application of different mitigation techniques during a turn-turn fault is presented. Both machine and drive structural adaptations for different fault mitigation techniques are addressed. Amongst the investigated fault mitigation techniques, the most promising solution is identified and validated experimentally. It is shown that the shorting terminal method adopting vertical winding arrangement is an effective method in terms of the implementation, reliability and weight

Upravljanje otporno na kvarove modularnim prekidačko-reluktantnim strojem nadahnuto prirodom

Fault tolerance is an obligatory feature in safety critical applications (aeronautical, aerospace, medical and military applications, power plants, etc.), where loss of life, environmental disasters, equipment destructions or unplanned downtimes must be avoided. For such applications, a novel bio-inspired motion control system is proposed. All its three components (the switched reluctance machine, the power converter and the control system) are designed to be as fault tolerant as possible. This paper describes all these three fault tolerant components: the bio-inspired control system having self-healing capabilities, the power converter with an extra leg and the fault tolerant modular machine. The theoretical expectations and simulation results are validated by means of laboratory experiments.Otpornost na kvarove je nužnost u sigurnosno kritičnim aplikacijama (aeronautičke, zrakoplovne, medicinske i vojne aplikacije, elektrane itd.), gdje je potrebno izbjeći smrtne slučajeve, prirodne nepogode, uništenje opreme ili neplanirane prekide u radu. Za takve aplikacije, predložen je novi slijedni sustav nadahnut prirodom. Sve tri komponente (prekidačko-reluktantni stroj, pretvarač i sustav upravljanja) su projektirani da budu što je više moguće otporni na kvarove. Ovaj rad opisuje sve tri komponente: sustav upravljanja nadahnut prirodom sa samoliječećim svojstvima, pretvarač s dodatnom granom i modularni stroj otporan na kvarove. Teoretska očekivanja i simulacijski rezultati su provjereni laboratorijskim eksperimentima

Multicountry Distribution and Characterization of Extended-spectrum β-Lactamase-associated Gram-negative Bacteria From Bloodstream Infections in Sub-Saharan Africa.

BACKGROUND: Antimicrobial resistance (AMR) is a major global health concern, yet, there are noticeable gaps in AMR surveillance data in regions such as sub-Saharan Africa. We aimed to measure the prevalence of extended-spectrum β-lactamase (ESBL) producing Gram-negative bacteria in bloodstream infections from 12 sentinel sites in sub-Saharan Africa. METHODS: Data were generated during the Typhoid Fever Surveillance in Africa Program (TSAP), in which standardized blood cultures were performed on febrile patients attending 12 health facilities in 9 sub-Saharan African countries between 2010 and 2014. Pathogenic bloodstream isolates were identified at the sites and then subsequently confirmed at a central reference laboratory. Antimicrobial susceptibility testing, detection of ESBL production, and conventional multiplex polymerase chain reaction (PCR) testing for genes encoding for β-lactamase were performed on all pathogens. RESULTS: Five hundred and five pathogenic Gram-negative bloodstream isolates were isolated during the study period and available for further characterization. This included 423 Enterobacteriaceae. Phenotypically, 61 (12.1%) isolates exhibited ESBL activity, and genotypically, 47 (9.3%) yielded a PCR amplicon for at least one of the screened ESBL genes. Among specific Gram-negative isolates, 40 (45.5%) of 88 Klebsiella spp., 7 (5.7%) of 122 Escherichia coli, 6 (16.2%) of 37 Acinetobacter spp., and 2 (1.3%) of 159 of nontyphoidal Salmonella (NTS) showed phenotypic ESBL activity. CONCLUSIONS: Our findings confirm the presence of ESBL production among pathogens causing bloodstream infections in sub-Saharan Africa. With few alternatives for managing ESBL-producing pathogens in the African setting, measures to control the development and proliferation of AMR organisms are urgently needed

The genomic epidemiology of multi-drug resistant invasive non-typhoidal Salmonella in selected sub-Saharan African countries

Funder: Swedish International Development Cooperation Agency (SIDA)Funder: Government of Republic of KoreaFunder: US Centers for Disease Control and PreventionBackground: Invasive non-typhoidal Salmonella (iNTS) is one of the leading causes of bacteraemia in sub-Saharan Africa. We aimed to provide a better understanding of the genetic characteristics and transmission patterns associated with multi-drug resistant (MDR) iNTS serovars across the continent. Methods: A total of 166 iNTS isolates collected from a multi-centre surveillance in 10 African countries (2010–2014) and a fever study in Ghana (2007–2009) were genome sequenced to investigate the geographical distribution, antimicrobial genetic determinants and population structure of iNTS serotypes–genotypes. Phylogenetic analyses were conducted in the context of the existing genomic frameworks for various iNTS serovars. Population-based incidence of MDR-iNTS disease was estimated in each study site. Results: Salmonella Typhimurium sequence-type (ST) 313 and Salmonella Enteritidis ST11 were predominant, and both exhibited high frequencies of MDR; Salmonella Dublin ST10 was identified in West Africa only. Mutations in the gyrA gene (fluoroquinolone resistance) were identified in S. Enteritidis and S. Typhimurium in Ghana; an ST313 isolate carrying blaCTX-M-15 was found in Kenya. International transmission of MDR ST313 (lineage II) and MDR ST11 (West African clade) was observed between Ghana and neighbouring West African countries. The incidence of MDR-iNTS disease exceeded 100/100 000 person-years-of-observation in children aged <5 years in several West African countries. Conclusions: We identified the circulation of multiple MDR iNTS serovar STs in the sampled sub-Saharan African countries. Investment in the development and deployment of iNTS vaccines coupled with intensified antimicrobial resistance surveillance are essential to limit the impact of these pathogens in Africa

Incidence of invasive salmonella disease in sub-Saharan Africa: a multicentre population-based surveillance study.

BACKGROUND: Available incidence data for invasive salmonella disease in sub-Saharan Africa are scarce. Standardised, multicountry data are required to better understand the nature and burden of disease in Africa. We aimed to measure the adjusted incidence estimates of typhoid fever and invasive non-typhoidal salmonella (iNTS) disease in sub-Saharan Africa, and the antimicrobial susceptibility profiles of the causative agents. METHODS: We established a systematic, standardised surveillance of blood culture-based febrile illness in 13 African sentinel sites with previous reports of typhoid fever: Burkina Faso (two sites), Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar (two sites), Senegal, South Africa, Sudan, and Tanzania (two sites). We used census data and health-care records to define study catchment areas and populations. Eligible participants were either inpatients or outpatients who resided within the catchment area and presented with tympanic (≥38·0°C) or axillary temperature (≥37·5°C). Inpatients with a reported history of fever for 72 h or longer were excluded. We also implemented a health-care utilisation survey in a sample of households randomly selected from each study area to investigate health-seeking behaviour in cases of self-reported fever lasting less than 3 days. Typhoid fever and iNTS disease incidences were corrected for health-care-seeking behaviour and recruitment. FINDINGS: Between March 1, 2010, and Jan 31, 2014, 135 Salmonella enterica serotype Typhi (S Typhi) and 94 iNTS isolates were cultured from the blood of 13 431 febrile patients. Salmonella spp accounted for 33% or more of all bacterial pathogens at nine sites. The adjusted incidence rate (AIR) of S Typhi per 100 000 person-years of observation ranged from 0 (95% CI 0-0) in Sudan to 383 (274-535) at one site in Burkina Faso; the AIR of iNTS ranged from 0 in Sudan, Ethiopia, Madagascar (Isotry site), and South Africa to 237 (178-316) at the second site in Burkina Faso. The AIR of iNTS and typhoid fever in individuals younger than 15 years old was typically higher than in those aged 15 years or older. Multidrug-resistant S Typhi was isolated in Ghana, Kenya, and Tanzania (both sites combined), and multidrug-resistant iNTS was isolated in Burkina Faso (both sites combined), Ghana, Kenya, and Guinea-Bissau. INTERPRETATION: Typhoid fever and iNTS disease are major causes of invasive bacterial febrile illness in the sampled locations, most commonly affecting children in both low and high population density settings. The development of iNTS vaccines and the introduction of S Typhi conjugate vaccines should be considered for high-incidence settings, such as those identified in this study. FUNDING: Bill & Melinda Gates Foundation

The phylogeography and incidence of multi-drug resistant typhoid fever in sub-Saharan Africa.

There is paucity of data regarding the geographical distribution, incidence, and phylogenetics of multi-drug resistant (MDR) Salmonella Typhi in sub-Saharan Africa. Here we present a phylogenetic reconstruction of whole genome sequenced 249 contemporaneous S. Typhi isolated between 2008-2015 in 11 sub-Saharan African countries, in context of the 2,057 global S. Typhi genomic framework. Despite the broad genetic diversity, the majority of organisms (225/249; 90%) belong to only three genotypes, 4.3.1 (H58) (99/249; 40%), 3.1.1 (97/249; 39%), and 2.3.2 (29/249; 12%). Genotypes 4.3.1 and 3.1.1 are confined within East and West Africa, respectively. MDR phenotype is found in over 50% of organisms restricted within these dominant genotypes. High incidences of MDR S. Typhi are calculated in locations with a high burden of typhoid, specifically in children aged <15 years. Antimicrobial stewardship, MDR surveillance, and the introduction of typhoid conjugate vaccines will be critical for the control of MDR typhoid in Africa

Short Note: Preliminary fish survey of Lac Tseny in north- western Madagascar

We surveyed the fish fauna of Lac Tseny, in the Sofia Region of northwestern Madagascar, during October 2010 by observing commercial catches and targeted netting of areas used by endemic species. We recorded seven native fish species at the lake, including three endemic cichlids, a herring and a catfish. We confirmed the continued survival of the Critically Endangered Paretroplus menarambo, as well as the presence of a Paretroplus taxon that may be new to science. The commercial fishery in the lake is sustained by introduced tilapiines and the native Sauvagella robusta. The three endemic cichlids (Paretroplus spp.) were not targeted by commercial fishermen, but when caught in small numbers were retained for domestic consumption. Submerged trees in the west of the lake restrict fishing with nets and probably provide important habitat for P. menarambo. Priority next steps at the lake include (i) additional surveys and biological studies of the endemic fish species and the Critically Endangered Madagascar big - headed turtle, Erymnochelys madagascariensis, (ii) clarification of the taxonomic status of Paretroplus cf. kieneri and, should it prove a new taxon, its formal scientific description, and (iii) continued engagement with fishing communities and authorities to promote practices that benefit livelihoods and the survival of threatened fish species.R&Eacute;SUM&Eacute;La composition sp&eacute;cifique de l&rsquo;ichtyofaune du lac Tseny, dans l&rsquo;ouest de Madagascar (r&eacute;gion de Sofia) a &eacute;t&eacute; inventori&eacute;e au cours du mois d&rsquo;octobre 2010, en observant les prises des p&ecirc;cheurs et des p&ecirc;ches cibl&eacute;es sur les esp&egrave;ces end&eacute;miques. Sept esp&egrave;ces de poissons indig&egrave;nes ont &eacute;t&eacute; observ&eacute;es, dont trois cichlid&eacute;s end&eacute;miques (Paretroplus menarambo, Paretroplus lamenabe et Paretroplus cf. kieneri), un hareng indig&egrave;ne (Sauvagella robusta) et un poisson-chat (Arius madagascariensis). Deux de ces esp&egrave;ces sont class&eacute;es comme Menac&eacute;es dans la Liste Rouge de l&rsquo;UICN&nbsp;: P. menarambo est une esp&egrave;ce en Danger Critique d&rsquo;Extinction qui n&rsquo;est connue que du lac Tseny et A. madagascariensis est une esp&egrave;ce en Danger d&rsquo;Extinction et end&eacute;mique de la r&eacute;gion de Sofia. Un des poissons que nous avons inventori&eacute; dans le genre Paretroplus semble &ecirc;tre une forme non d&eacute;crite. Les p&ecirc;cheurs ont indiqu&eacute; que P. menarambo est associ&eacute; &agrave; des arbres immerg&eacute;s le long de la rive occidentale du lac qui offrent un habitat propice &agrave; la reproduction et &agrave; l&rsquo;alimentation. Ces arbres immerg&eacute;s emp&ecirc;chent l&rsquo;utilisation des filets pour la p&ecirc;che et limitent ainsi la pression de p&ecirc;che qui s&rsquo;exerce sur cette esp&egrave;ce. Les trois esp&egrave;ces end&eacute;miques de Paretroplus sont pris&eacute;es par les p&ecirc;cheurs qui les gardent pour leur consommation personnelle plut&ocirc;t que de les vendre. La p&ecirc;che commerciale pratiqu&eacute;e dans le lac semble p&eacute;renne gr&acirc;ce &agrave; la pr&eacute;sence de tilapias allog&egrave;nes et du hareng indig&egrave;ne (Sauvagella robusta) qui approvisionnent les march&eacute;s de poisson local (Tsaratanana), r&eacute;gionaux (Boriziny et Mandritsara) et national (Antananarivo). Les populations locales ont rapport&eacute; que la surp&ecirc;che, l&rsquo;immigration, l&rsquo;utilisation ill&eacute;gale de filets &agrave; petit maillage et le non respect de la saison de fermeture de la p&ecirc;che &eacute;taient les principales menaces pesant sur l&rsquo;ichtyofaune du lac Tseny. Une baisse de la p&ecirc;che commerciale pourrait entra&icirc;ner une ru&eacute;e vers les esp&egrave;ces end&eacute;miques et l&rsquo;ouverture des zones d&rsquo;arbres immerg&eacute;s pour la p&ecirc;che. Le lac Tseny abrite un assemblage unique de poissons qui doivent &ecirc;tre prot&eacute;g&eacute;s dans leur habitat qui est essentiel aux cichlid&eacute;s end&eacute;miques par le maintien d&rsquo;une p&ecirc;che commerciale p&eacute;renne. Les prochaines &eacute;tapes &agrave; mener en priorit&eacute; pour le lac incluent&nbsp;: (i) des &eacute;tudes suppl&eacute;mentaires sur la biologie des poissons end&eacute;miques et de la Podocn&eacute;mide de Madagascar (Erymnochelys madagascariensis), une tortue en Danger Critique d&rsquo;Extinction, (ii) la clarification du statut taxinomique de Paretroplus cf. kieneri qui pourrait &ecirc;tre une nouvelle esp&egrave;ce et sa description, le cas &eacute;ch&eacute;ant, et (iii) l&rsquo;engagement continu avec les communaut&eacute;s de p&ecirc;cheurs et les autorit&eacute;s locales pour promouvoir des pratiques &eacute;quitables en faveur des populations riveraines et pour la survie des esp&egrave;ces de poissons menac&eacute;es