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Philip B. James - One of the best experts on this subject based on the ideXlab platform.
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MINIMAL AEROSOL LOADING AND GLOBAL INCREASES IN ATMOSPHERIC OZONE DURING THE 1996-1997 MARTIAN NORTHERN Spring Season
Icarus, 1999Co-Authors: R. Todd Clancy, Michael J. Wolff, Philip B. JamesAbstract:We employed the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) to observe middle ultraviolet (220–330 nm) spectral scans of Mars for two periods during the 1996–1997 northern Spring Season. Analysis of these data yields quantitative measurements of atmospheric column opacities for aerosols and ozone over a wide range of latitudes (40°S–70°N) in two Mars Seasons (solar longitudes,Lsof 10° and 61°). The most significant findings of the analysis are: (1) the global Mars atmosphere exhibited minimal aerosol loading during this Season (variable opacities of 0.02–0.08 for clouds, or 0.05–0.2 for dust); (2) the low-to-mid latitude ozone abundance in the Mars atmosphere increased by roughly a factor of two (from 1.8 to 3.6 μm-atm) betweenLs=10° andLs=61°. These results support previous predictions (R. T. Clancy and H. Nair 1996,J. Geophys. Res.101, 12785–12790) and observations (R. T. Clancyet al.1996b,J. Geophys. Res.101, 12777–12783) of orbital (Ls) variations in Mars global ozone abundances, as driven by orbital variations in the global altitudes of water vapor saturation (R. T. Clancyet al.1996a,Icarus122, 36–62). They also support conclusions of very low dust levels in the Mars atmosphere around aphelion (Clancyet al.1996a), with upper limits for background dust opacities which are several times lower than described for this Season by the Viking-based dusty model of the Mars climate (e.g.,τ
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minimal aerosol loading and global increases in atmospheric ozone during the 1996 1997 martian northern Spring Season
Icarus, 1999Co-Authors: Todd R Clancy, Michael J. Wolff, Philip B. JamesAbstract:We employed the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) to observe middle ultraviolet (220–330 nm) spectral scans of Mars for two periods during the 1996–1997 northern Spring Season. Analysis of these data yields quantitative measurements of atmospheric column opacities for aerosols and ozone over a wide range of latitudes (40°S–70°N) in two Mars Seasons (solar longitudes,Lsof 10° and 61°). The most significant findings of the analysis are: (1) the global Mars atmosphere exhibited minimal aerosol loading during this Season (variable opacities of 0.02–0.08 for clouds, or 0.05–0.2 for dust); (2) the low-to-mid latitude ozone abundance in the Mars atmosphere increased by roughly a factor of two (from 1.8 to 3.6 μm-atm) betweenLs=10° andLs=61°. These results support previous predictions (R. T. Clancy and H. Nair 1996,J. Geophys. Res.101, 12785–12790) and observations (R. T. Clancyet al.1996b,J. Geophys. Res.101, 12777–12783) of orbital (Ls) variations in Mars global ozone abundances, as driven by orbital variations in the global altitudes of water vapor saturation (R. T. Clancyet al.1996a,Icarus122, 36–62). They also support conclusions of very low dust levels in the Mars atmosphere around aphelion (Clancyet al.1996a), with upper limits for background dust opacities which are several times lower than described for this Season by the Viking-based dusty model of the Mars climate (e.g.,τ<0.2, here; versus 0.6; D. S. Colburnet al.1989,Icarus79, 159–189). Also of interest is the observation of substantially reduced cloud opacities for the “aphelion cloud belt” in early northern Spring (Ls∼ 60°) in 1997, versus 1995 or 1991.
Grazia M Revello - One of the best experts on this subject based on the ideXlab platform.
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detection and pathogenicity of human metapneumovirus respiratory infection in pediatric italian patients during a winter Spring Season
Journal of Clinical Virology, 2006Co-Authors: Antonella Sarasini, Francesca Rovida, Giulia Campanini, Emilia Genini, Maria Torsellini, Stefania Paolucci, Fausto Baldanti, Antonietta Marchi, Elena Percivalle, Grazia M RevelloAbstract:Abstract Background Some diagnostic, epidemiological and clinical features of the recently discovered human metapneumovirus remain to be investigated. Objectives To study the best approach for the diagnosis of human metapneumovirus infections by both conventional and molecular methods, along with the human metapneumovirus circulation rate in northern Italy and the severity of human metapneumovirus respiratory infections in a pediatric patient population. Study design Nasopharyngeal aspirates (NPA) were taken from 306 pediatric patients during the winter–Spring Season 2003–2004, and examined for conventional respiratory viruses by direct fluorescent staining and cell culture, while human coronavirus and human metapneumovirus were sought by RT-PCR. Results RT-PCR detected human metapneumovirus in 40/306 (13.1%) children positive for respiratory viruses, with an incidence intermediate between that of respiratory syncytial virus (58 patients, 18.9%) and that of influenzavirus infections (29 patients, 9.5%). Phylogenetic analysis showed cocirculation of both human metapneumovirus types (A and B) as well as their relevant subtypes (A1–A2 and B1–B2). Clinically, human metapneumovirus was found to be second to human respiratory syncytial virus alone, as a cause of respiratory tract infections, while duration of virus excretion appeared to correlate with severity of infection, and virus load in NPA with the stage of respiratory infection. Conclusion (i) Human metapneumovirus is a major viral pathogen in the Italian pediatric patient population; (ii) the severity of lower respiratory tract infections approaches that of human respiratory syncytial virus; (iii) there are preliminary indications that the duration of virus excretion may reach 2–3 weeks and that the level of viral load in NPA correlates with the clinical stage of human metapneumovirus infection.
Re Okoola - One of the best experts on this subject based on the ideXlab platform.
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a diagnostic study of the eastern africa monsoon circulation during the northern hemisphere Spring Season
International Journal of Climatology, 1999Co-Authors: Re OkoolaAbstract:The eastern Africa monsoons during the Northern Hemisphere Spring (NHS) Season are described based on composites derived from various rainfall anomaly scenarios. The years 1981/1984 were delineated as some of the recent wettest/driest years over this region during the NHS Season. Wet/dry spells within these anomalous years were further selected using PCA T-mode analysis. Both the anomalous years and the wet/dry spells identified from these years were used to create wind composites that were used to describe the eastern Africa Monsoon circulation. Composite wind analyses showed the dominance of the westerlies/easterlies in the lower/upper troposphere and their migration from the Southern Hemisphere to the Northern Hemisphere. Analysis of the individual wettest/driest years showed that before the start of the equatorial eastern Africa (EEA) long-rains Season, easterlies are dominant near the Equator and westerlies near 15°S in the lower troposphere, while at the end of the rainy Season the westerlies were located to the north of the Equator, near 5°N, with easterlies on their lateral sides. However, during the EEA long-rains Season westerly/easterly wind events occurred in alternation over the region. These westerly/easterly episodes were associated with wet/dry rainfall spells. Vertical sections of zonal wind component showed that the wind alignment during wet spells was similar to that generally observed in other monsoonal regions, with lower tropospheric westerlies overlain by upper tropospheric easterlies. But the reduced frequency of lower tropospheric westerlies is suggested to be due to the barrier effect of the north–south mountain chains which allow only the most intense westerlies to cross the mountains into the EEA region. Copyright © 1999 Royal Meteorological Society
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Spatial evolutions of the active convective patterns across the Equatorial Eastern Africa region during northern hemisphere Spring Season using Outgoing Longwave Radiation records
Meteorology and Atmospheric Physics, 1998Co-Authors: Re OkoolaAbstract:This study has used low Outgoing Longwave Radiation (OLR) values to study the structure and evolution of the active convection across Equatorial Eastern Africa (EEA) region (5° N to 10° S, 28° E to 42° E) during the northern hemisphere Spring Season. This involved the examination of the map patterns and cross-sections of OLR data as derived from once-daily NOAA's Operational Polar Orbiting satellites within the period June 1974 to May 1991.
Antonella Sarasini - One of the best experts on this subject based on the ideXlab platform.
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detection and pathogenicity of human metapneumovirus respiratory infection in pediatric italian patients during a winter Spring Season
Journal of Clinical Virology, 2006Co-Authors: Antonella Sarasini, Francesca Rovida, Giulia Campanini, Emilia Genini, Maria Torsellini, Stefania Paolucci, Fausto Baldanti, Antonietta Marchi, Elena Percivalle, Grazia M RevelloAbstract:Abstract Background Some diagnostic, epidemiological and clinical features of the recently discovered human metapneumovirus remain to be investigated. Objectives To study the best approach for the diagnosis of human metapneumovirus infections by both conventional and molecular methods, along with the human metapneumovirus circulation rate in northern Italy and the severity of human metapneumovirus respiratory infections in a pediatric patient population. Study design Nasopharyngeal aspirates (NPA) were taken from 306 pediatric patients during the winter–Spring Season 2003–2004, and examined for conventional respiratory viruses by direct fluorescent staining and cell culture, while human coronavirus and human metapneumovirus were sought by RT-PCR. Results RT-PCR detected human metapneumovirus in 40/306 (13.1%) children positive for respiratory viruses, with an incidence intermediate between that of respiratory syncytial virus (58 patients, 18.9%) and that of influenzavirus infections (29 patients, 9.5%). Phylogenetic analysis showed cocirculation of both human metapneumovirus types (A and B) as well as their relevant subtypes (A1–A2 and B1–B2). Clinically, human metapneumovirus was found to be second to human respiratory syncytial virus alone, as a cause of respiratory tract infections, while duration of virus excretion appeared to correlate with severity of infection, and virus load in NPA with the stage of respiratory infection. Conclusion (i) Human metapneumovirus is a major viral pathogen in the Italian pediatric patient population; (ii) the severity of lower respiratory tract infections approaches that of human respiratory syncytial virus; (iii) there are preliminary indications that the duration of virus excretion may reach 2–3 weeks and that the level of viral load in NPA correlates with the clinical stage of human metapneumovirus infection.
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Detection and pathogenicity of human metapneumovirus respiratory infection in pediatric Italian patients during a winter–Spring Season
Journal of Clinical Virology, 2005Co-Authors: Antonella Sarasini, Francesca Rovida, Giulia Campanini, Emilia Genini, Maria Torsellini, Stefania Paolucci, Fausto Baldanti, Antonietta Marchi, Elena Percivalle, M. Grazia RevelloAbstract:Abstract Background Some diagnostic, epidemiological and clinical features of the recently discovered human metapneumovirus remain to be investigated. Objectives To study the best approach for the diagnosis of human metapneumovirus infections by both conventional and molecular methods, along with the human metapneumovirus circulation rate in northern Italy and the severity of human metapneumovirus respiratory infections in a pediatric patient population. Study design Nasopharyngeal aspirates (NPA) were taken from 306 pediatric patients during the winter–Spring Season 2003–2004, and examined for conventional respiratory viruses by direct fluorescent staining and cell culture, while human coronavirus and human metapneumovirus were sought by RT-PCR. Results RT-PCR detected human metapneumovirus in 40/306 (13.1%) children positive for respiratory viruses, with an incidence intermediate between that of respiratory syncytial virus (58 patients, 18.9%) and that of influenzavirus infections (29 patients, 9.5%). Phylogenetic analysis showed cocirculation of both human metapneumovirus types (A and B) as well as their relevant subtypes (A1–A2 and B1–B2). Clinically, human metapneumovirus was found to be second to human respiratory syncytial virus alone, as a cause of respiratory tract infections, while duration of virus excretion appeared to correlate with severity of infection, and virus load in NPA with the stage of respiratory infection. Conclusion (i) Human metapneumovirus is a major viral pathogen in the Italian pediatric patient population; (ii) the severity of lower respiratory tract infections approaches that of human respiratory syncytial virus; (iii) there are preliminary indications that the duration of virus excretion may reach 2–3 weeks and that the level of viral load in NPA correlates with the clinical stage of human metapneumovirus infection.
Todd R Clancy - One of the best experts on this subject based on the ideXlab platform.
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minimal aerosol loading and global increases in atmospheric ozone during the 1996 1997 martian northern Spring Season
Icarus, 1999Co-Authors: Todd R Clancy, Michael J. Wolff, Philip B. JamesAbstract:We employed the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) to observe middle ultraviolet (220–330 nm) spectral scans of Mars for two periods during the 1996–1997 northern Spring Season. Analysis of these data yields quantitative measurements of atmospheric column opacities for aerosols and ozone over a wide range of latitudes (40°S–70°N) in two Mars Seasons (solar longitudes,Lsof 10° and 61°). The most significant findings of the analysis are: (1) the global Mars atmosphere exhibited minimal aerosol loading during this Season (variable opacities of 0.02–0.08 for clouds, or 0.05–0.2 for dust); (2) the low-to-mid latitude ozone abundance in the Mars atmosphere increased by roughly a factor of two (from 1.8 to 3.6 μm-atm) betweenLs=10° andLs=61°. These results support previous predictions (R. T. Clancy and H. Nair 1996,J. Geophys. Res.101, 12785–12790) and observations (R. T. Clancyet al.1996b,J. Geophys. Res.101, 12777–12783) of orbital (Ls) variations in Mars global ozone abundances, as driven by orbital variations in the global altitudes of water vapor saturation (R. T. Clancyet al.1996a,Icarus122, 36–62). They also support conclusions of very low dust levels in the Mars atmosphere around aphelion (Clancyet al.1996a), with upper limits for background dust opacities which are several times lower than described for this Season by the Viking-based dusty model of the Mars climate (e.g.,τ<0.2, here; versus 0.6; D. S. Colburnet al.1989,Icarus79, 159–189). Also of interest is the observation of substantially reduced cloud opacities for the “aphelion cloud belt” in early northern Spring (Ls∼ 60°) in 1997, versus 1995 or 1991.
