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Full-Text Articles in Physical Sciences and Mathematics

Consistency Of Projected Drought Over The Sahel With Changes In The Monsoon Circulation And Extremes In A Regional Climate Model Projections, M. B. Sylla, A. T. Gaye, G. S. Jenkins, Jeremy S. Pal, F. Giorgi Sep 2017

Consistency Of Projected Drought Over The Sahel With Changes In The Monsoon Circulation And Extremes In A Regional Climate Model Projections, M. B. Sylla, A. T. Gaye, G. S. Jenkins, Jeremy S. Pal, F. Giorgi

Jeremy Pal

As a step toward an increased understanding of climate change over West Africa, in this paper we analyze the relationship between rainfall changes and monsoon dynamics in high-resolution regional climate model experiments performed using the Regional Climate Model (RegCM3). Multidecadal simulations are carried out for present-day and future climate conditions under increased greenhouse gas forcing driven by the global climate model European Center/Hamburg 5 (ECHAM5). Compared to the present day, the future scenario simulation produces drier conditions over the Sahel and wetter conditions over orographic areas. The Sahel drying is accompanied by a weaker monsoon flow, a southward migration and …


Propagation Of Tsunami-Driven Gravity Waves Into The Thermosphere And Ionosphere, Michael P. Hickey, G. Schubert, R. L. Walterscheid Dec 2015

Propagation Of Tsunami-Driven Gravity Waves Into The Thermosphere And Ionosphere, Michael P. Hickey, G. Schubert, R. L. Walterscheid

Michael P. Hickey

Recent observations have revealed large F-region electron density perturbations (~100%) and total electron content (TEC) perturbations (~30%) that appear to be correlated with tsunamis. The characteristic speed and horizontal wavelength of the disturbances are ~200 m/s and ~400 km. We describe numerical simulations using our spectral full-wave model (SFWM) of the upward propagation of a spectrum of gravity waves forced by a tsunami, and the interaction of these waves with the F-region ionosphere. The SFWM describes the propagation of linear, steady-state acoustic-gravity waves in a nonisothermal atmosphere with the inclusion of eddy and molecular diffusion of heat and momentum, ion …


Propagation Of Tsunami-Driven Gravity Waves Into The Thermosphere And Ionosphere, Michael P. Hickey, G. Schubert, R. L. Walterscheid Dec 2015

Propagation Of Tsunami-Driven Gravity Waves Into The Thermosphere And Ionosphere, Michael P. Hickey, G. Schubert, R. L. Walterscheid

Michael P. Hickey

Recent observations have revealed large F-region electron density perturbations (~100%) and total electron content (TEC) perturbations (~30%) that appear to be correlated with tsunamis. The characteristic speed and horizontal wavelength of the disturbances are ~200 m/s and ~400 km. We describe numerical simulations using our spectral full-wave model (SFWM) of the upward propagation of a spectrum of gravity waves forced by a tsunami, and the interaction of these waves with the F-region ionosphere. The SFWM describes the propagation of linear, steady-state acoustic-gravity waves in a nonisothermal atmosphere with the inclusion of eddy and molecular diffusion of heat and momentum, ion …


New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, Fernando J. Capalbo, Yves Bénilan, Nicolas Fray, Martin Schwell, Norbert Champion, Et-Touhami Es-Sebbar, Tommi T. Koskinen, Ivan Lehocki, Roger V. Yelle Oct 2015

New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, Fernando J. Capalbo, Yves Bénilan, Nicolas Fray, Martin Schwell, Norbert Champion, Et-Touhami Es-Sebbar, Tommi T. Koskinen, Ivan Lehocki, Roger V. Yelle

Dr. Et-touhami Es-sebbar

Benzene is an important molecule in Titan’s atmosphere because it is a potential link between the gas phase and the organic solid phase. We measured photoabsorption in the ultraviolet by benzene gas at temperatures covering the range from room temperature to 215 K. We derived benzene absorption cross sections and analyzed them in terms of the transitions observed. No significant variation with measurement temperature was observed. We discuss the implications of our measurements for the derivation of benzene abundance profiles in Titan’s thermosphere, by the Cassini/Ultraviolet Imaging Spectrograph (UVIS). The use of absorption cross sections at low temperature is recommended …


Energetics Of Magnetic Storms Driven By Corotating Interaction Regions: A Study Of Geoeffectiveness, Niescja E. Turner, E J. Mitchell, D J. Knipp, B A. Emery Oct 2013

Energetics Of Magnetic Storms Driven By Corotating Interaction Regions: A Study Of Geoeffectiveness, Niescja E. Turner, E J. Mitchell, D J. Knipp, B A. Emery

Niescja E. Turner

We investigate the energetics of magnetic storms associated with corotating interaction regions (CIRs). We analyze 24 storms driven by CIRs and compare to 18 driven by ejecta-related events to determine how they differ in overall properties and in particular in their distribution of energy. To compare these different types of events, we look at events with comparable input parameters such as the epsilon parameter and note the properties of the resulting storms. We estimate the energy output by looking at the ring current energy along with ionospheric Joule heating derived from the PC and Dst indices. We also include the …


Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen Jan 2012

Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen

Pr. Mamoudou H. DICKO, PhD

The antimicrobial activity of 8 Bacillus spp. and 2 Lysinibacillus spp. representing the predominant aerobic sporeformers during traditional maari fermentations, a traditional fermented baobab seeds product fromBurkina Faso,was investigated. The antimicrobial activitywas assessed against a total of 31 indicator organisms representing various Gram-negative and positive pathogens. The screening showed that 3 Bacillus subtilis strains (B3, B122 and B222) in particular had antimicrobial activity against some Gram-positive organisms and were selected for further studies. Itwas found that the antimicrobial substances producedwere heat stable, in-sensitive to catalase, sensitive to protease and trypsin but resistant to the proteolytic action of papain and proteinase …