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A. I. Pogoreltsev - One of the best experts on this subject based on the ideXlab platform.

  • dynamics of 2013 sudden stratospheric warming event and its impact on Cold Weather over eurasia role of planetary wave reflection
    Scientific Reports, 2016
    Co-Authors: Debashis Nath, Cai Zelin, Wen Chen, A. I. Pogoreltsev
    Abstract:

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric Weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (SSW) event. We analyze EP fluxes and Plumb wave activity fluxes to study the two and three dimensional aspects of wave propagation, respectively. The 2013 SSW event is excited by the combined influence of wavenumber 1 (WN1) and wavenumber 2 (WN2) planetary waves, which makes the event an unusual one and seems to have significant impact on tropospheric Weather regime. We observe an extraordinary development of a ridge over the Siberian Tundra and the North Pacific during first development stage (last week of December 2012) and later from the North Atlantic in the second development stage (first week of January 2013), and these waves appear to be responsible for the excitation of the WN2 pattern during the SSW. The wave packets propagated upward and were then reflected back down to central Eurasia due to strong negative wind shear in the upper stratospheric polar jet, caused by the SSW event. Waves that propagated downward led to the formation of a deep trough over Eurasia and brought extreme Cold Weather over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013.

Philippe Brouqui - One of the best experts on this subject based on the ideXlab platform.

  • AUTOCHTHONOUS EPIDEMIC TYPHUS ASSOCIATED WITH BARTONELLA
    2014
    Co-Authors: Homeless A Person, Sékéné Badiaga, Philippe Brouqui
    Abstract:

    Abstract. Trench fever, a louse-borne disease caused by Bartonella quintana, is reemerging in homeless persons. Epidemic typhus is another life-threatening louse-borne disease caused by Rickettsia prowazekii and known to occur in conditions of war, famine, refugee camps, Cold Weather, poverty, or lapses in public health. We report the first case of seroconversion to R. prowazekii in a homeless person of Marseilles, France. This was associated with B. quintana bacteremia. Although no outbreaks of typhus have been notified yet in the homeless population, this disease is likely to reemerge in such situation

  • Autochthonous epidemic typhus associated with Bartonella quintana bacteremia in a homeless person.
    The American journal of tropical medicine and hygiene, 2005
    Co-Authors: Sékéné Badiaga, Philippe Brouqui
    Abstract:

    Trench fever, a louse-borne disease caused by Bartonella quintana, is reemerging in homeless persons. Epidemic typhus is another life-threatening louse-borne disease caused by Rickettsia prowazekii and known to occur in conditions of war, famine, refugee camps, Cold Weather, poverty, or lapses in public health. We report the first case of seroconversion to R. prowazekii in a homeless person of Marseilles, France. This was associated with B. quintana bacteremia. Although no outbreaks of typhus have been notified yet in the homeless population, this disease is likely to reemerge in such situation.

Debashis Nath - One of the best experts on this subject based on the ideXlab platform.

  • dynamics of 2013 sudden stratospheric warming event and its impact on Cold Weather over eurasia role of planetary wave reflection
    Scientific Reports, 2016
    Co-Authors: Debashis Nath, Cai Zelin, Wen Chen, A. I. Pogoreltsev
    Abstract:

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric Weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (SSW) event. We analyze EP fluxes and Plumb wave activity fluxes to study the two and three dimensional aspects of wave propagation, respectively. The 2013 SSW event is excited by the combined influence of wavenumber 1 (WN1) and wavenumber 2 (WN2) planetary waves, which makes the event an unusual one and seems to have significant impact on tropospheric Weather regime. We observe an extraordinary development of a ridge over the Siberian Tundra and the North Pacific during first development stage (last week of December 2012) and later from the North Atlantic in the second development stage (first week of January 2013), and these waves appear to be responsible for the excitation of the WN2 pattern during the SSW. The wave packets propagated upward and were then reflected back down to central Eurasia due to strong negative wind shear in the upper stratospheric polar jet, caused by the SSW event. Waves that propagated downward led to the formation of a deep trough over Eurasia and brought extreme Cold Weather over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013.

  • planetary wave reflection and its impact on tropospheric Cold Weather over asia during january 2008
    Advances in Atmospheric Sciences, 2014
    Co-Authors: Debashis Nath, Wen Chen, Lin Wang
    Abstract:

    Reflection of stratospheric planetary waves and its impact on tropospheric Cold Weather over Asia during January 2008 were investigated by applying two dimensional Eliassen-Palm (EP) flux and three-dimensional Plumb wave activity fluxes. The planetary wave propagation can clearly be seen in the longitude-height and latitude-height sections of the Plumb wave activity flux and EP flux, respectively, when the stratospheric basic state is partially reflective. Primarily, a wave packet emanating from Baffin Island/coast of Labrador propagated eastward, equatorward and was reflected over Central Eurasia and parts of China, which in turn triggered the advection of Cold wind from the northern part of the boreal forest regions and Siberia to the subtropics. The wide region of Central Eurasia and China experienced extreme Cold Weather during the second ten days of January 2008, whereas the extraordinary persistence of the event might have occurred due to an anomalous blocking high in the Urals-Siberia region.

C Gehlen - One of the best experts on this subject based on the ideXlab platform.

  • effect of calcium nitrate on the freeze thaw resistance of concrete
    BFT International, 2015
    Co-Authors: W Franke, C Thiel, F Duran, C Gehlen
    Abstract:

    Concrete in Cold climates is not only exposed to Cold Weather while concreting but also to freeze-thaw cycles during its lifetime. Thus not only the concrete production needs to be adjusted to the environmental conditions but also the mixture has to be durable and resist the environmental impacts. Commonly an air entraining agent is used to interrupt the capillary pore system and to provide further space for the freezing water to expand. The downside of this approach is a loss in compressive strength. Within this paper the effect of simultaneous use of air entraining agent and calcium nitrate is discussed.

Hakan Nilsson - One of the best experts on this subject based on the ideXlab platform.

  • correction of clothing insulation for movement and wind effects a meta analysis
    European Journal of Applied Physiology, 2004
    Co-Authors: George Havenith, Hakan Nilsson
    Abstract:

    A meta-analysis of the effect of body and air movement on the insulation provided by workwear and Cold-Weather clothing [1.22 clo (0.189 m2 °C W−1) Cold-Weather clothing (r2=0.97). Differences were mainly due to the different amounts of nude surface area. An interaction between wind and walking effects was present (the size of the combined effects is less than the sum of the separate effects), and for Cold-Weather clothing an effect of clothing air permeability (p) was present (high p→bigger effect). The resulting prediction equations will be proposed for inclusion in European and ISO standards on protective clothing to assist the user in determining the real-life clothing insulation value.