63 research outputs found

    Microclimate and the Zoonotic Cycle of Tick-Borne Encephalitis Virus in Switzerland

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    The focal distribution of tick-borne encephalitis virus (TBEV; Flaviviridae, Flavivirus) appears to depend mainly on cofeeding transmission between infected Ixodes ricinus L. nymphs and uninfected larvae. To better understand the role of cofeeding ticks in the transmission of TBEV, we investigated tick infestation of rodents and the influence of microclimate on the seasonality of questing I. ricinus ticks. A 3-yr study was carried out at four sites, including two confirmed TBEV foci. Free-living ticks and rodents were collected monthly, and microclimatic data were recorded. A decrease in questing nymph density was observed in 2007, associated with low relative humidity and high temperatures in spring. One site, Thun, did not show this decrease, probably because of microclimatic conditions in spring that favored the questing nymph population. During the same year, the proportion of rodents carrying cofeeding ticks was lower at sites where the questing nymph density decreased, although the proportion of infested hosts was similar among years. TBEV was detected in 0.1% of questing ticks, and in 8.6 and 50.0% of larval ticks feeding on two rodents. TBEV was detected at all but one site, where the proportion of hosts with cofeeding ticks was the lowest. The proportion of hosts with cofeeding ticks seemed to be one of the factors that distinguished a TBEV focus from a non-TBEV focus. The enzootic cycle of TBEV might be disrupted when dry and hot springs occur during consecutive year

    Prevalence and Genotyping of Tick-Borne Encephalitis Virus in Questing Ixodes ricinus Ticks in a New Endemic Area in Western Switzerland

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    Tick-borne encephalitis virus (TBEV) is the causative agent of tick-borne encephalitis (TBE) and causes neurological disease in humans in Eurasia. TBEV is transmitted by ticks of the genus Ixodes. Currently 10,000-12,000 clinical cases are reported annually in ≈30 TBE endemic countries. Since 1990 the epidemiology of TBE is characterized by a global increase of clinical cases and an expansion of risk areas. Similar trends are also observed in Switzerland but few studies confirmed the emergence of new TBE foci by detecting viral RNA in field-collected ticks. In this study, free-living Ixodes ricinus (L.) ticks from one nonendemic and three new TBE endemic regions located in the Western part of Switzerland were screened during four consecutive years (2007-2010) for the presence of TBEV. A total of 9,868 I. ricinus ticks (6,665 nymphs and 3,203 adults) were examined in pools for TBEV by real-time reverse transcription polymerase chain reaction. Our results confirmed the presence of viral RNA in 0.1% (6/6120) of questing ticks collected in one new endemic region. Among TBE endemic sites, the minimal infection rate per 100 ticks tested ranged from 0.21 (1/477) to 0.95 (1/105). Four positive samples were sequenced and phylogenetic analysis of the NS5 gene showed that all TBEV nucleotide sequences belonged to the European subtype and were split into two distinct lineages originating probably independently from two distinct foci located North-East and East of the study regio

    How do MNC R&D laboratory roles affect employee international assignments?

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    Research and development (R&D) employees are important human resources for multinational corporations (MNCs) as they are the driving force behind the advancement of innovative ideas and products. International assignments of these employees can be a unique way to upgrade their expertise; allowing them to effectively recombine their unique human resources to progress existing knowledge and advance new ones. This study aims to investigate the effect of the roles of R&D laboratories in which these employees work on the international assignments they undertake. We categorise R&D laboratory roles into those of the support laboratory, the locally integrated laboratory and the internationally interdependent laboratory. Based on the theory of resource recombinations, we hypothesise that R&D employees in support laboratories are not likely to assume international assignments, whereas those in locally integrated and internationally interdependent laboratories are likely to assume international assignments. The empirical evidence, which draws from research conducted on 559 professionals in 66 MNC subsidiaries based in Greece, provides support to our hypotheses. The resource recombinations theory that extends the resource based view can effectively illuminate the international assignment field. Also, research may provide more emphasis on the close work context of R&D scientists rather than analyse their demographic characteristics, the latter being the focus of scholarly practice hitherto

    Wykorzystanie planów Plackett a-Burmana i analizy opinii ekspertów w celu oceny istotności parametrów sterowalnych procesu cięcia plazmowego

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    This article evaluates the significance of controllable parameters in the plasma cutting process, using the Plackett-Burman Method and the Analysis of Expert Opinions Method. The plasma cutting process was tested using a WPA-6000 Compakt plasma cutter, on non-alloy steel, of the S235JR EN 10025-2:2007 grade, with a carbon equivalent of 0.35%. The effect of the thickness of the sheet, the current flow rate, the cutting speed, the gas pressure during cutting, the height of the torch during cutting, the pierce delay time and the initial pierce height, were analysed. The research revealed the influence of the controllable parameters tested, in the plasma cutting process, on selected output parameters, surface cut drag lines, the width of the kerf at the inlet and outlet, and the value of the perpendicularity of the kerf on the surface of the base. The greatest influences were recorded for intensity of cutting current, cutting speed and gas pressure during cutting. The results obtained were confirmed by the results of the analysis of expert opinions.W artykule dokonano oceny istotności parametrów sterowalnych procesu cięcia plazmowego za pomocą metody Placketta-Burmana i analizy opinii ekspertów. Badania procesu cięcia plazmowego przeprowadzono przy użyciu przecinarki plazmowej WPA- 6000 Compakt na stali niestopowej konstrukcyjnej gatunku S235JR EN 10025-2:2007 z ekwiwalentem węglowym wynoszącym 0.35 %. Analizowano wpływ grubości blachy, natężenia prądu, prędkości cięcia, ciśnienia gazów podczas cięcia, odstępu palnika od blachy podczas cięcia, czasu dziurkowania oraz wysokości startu. Badania ujawniły wpływ badanych parametrów sterowalnych procesu cięcia plazmowego na wybrane parametry wyjściowe, w szczególności na skok śladów cięcia, na szerokość szczeliny na wejściu i wyjściu oraz na wartość prostopadłości szczeliny do powierzchni bazowej. Największe wpływy zarejestrowano dla natężenia prądu, prędkości cięcia oraz ciśnienia gazu podczas cięcia. Otrzymane wyniki badań zostały potwierdzone wynikami analizy opinii ekspertów

    On the Features of Composite Coating, Based on Nickel Alloy and Aluminum–Iron Bronze, Processed by Direct Metal Deposition

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    In recent years, additive manufacturing technologies have become increasingly widespread with the most intensive development being direct metal deposition (DMD), alloys, and ceramic materials on a metal substrate. This study shows the possibilities of the effective formation of coatings, based on heterogeneous metal alloys (Ni-based alloy and Fe-Al bronze) deposited onto 1045 structural steel. Changes in the microhardness, the microstructure, and the tribological properties of the composite coating, depending on the laser spot speed and pitch during DMD processing, have been considered. It was revealed that if the components of the composite coating are chosen correctly, there are possible DMD conditions ensuring reliable and durable connection between them and with the substrate
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