Between January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings require... more Between January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings required surgical intervention at this center. Nineteen patients had double aortic arch (group I); 13 patients had vascular ring consisting of right aortic arch, anomalous origin of the left subclavian artery, and ligamentum arteriosus (group II); eight patients had innominate artery compression (group III); and four patients had pulmonary artery sling (group IV). Three patients had complex congenital heart defect and died secondary to it and are excluded from the study. Follow-up was obtained on 31 patients (76%). The follow-up period ranged from 0.4 years to 10.9 years, with a mean of 3.6 years. Seventy percent of the overall group were asymptomatic, and 30% of patients continued to have upper and lower respiratory symptoms on late follow-up. One third of patients in groups I and II, who underwent surgical repair, continue to have symptoms. Patients who have persistent symptoms should be furt...
We report the first observations of polar mesosphere summer echoes (PMSE) above the high-latitude... more We report the first observations of polar mesosphere summer echoes (PMSE) above the high-latitude Southern Hemisphere (SH) station Davis, Antarctica (68.6°S, 78.0°E geographic; 74.6°S magnetic). Observations were obtained using a 55 MHz atmospheric radar, the first stage of which was commissioned late in the austral summer of 2002–2003. The radar commenced mesosphere observations with approximately 20 kW of transmitted power
MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in... more MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in Antarctica operate concurrently and provide unprecedented global-scale coverage of the polar wind field in the mesosphere and lower thermosphere (MLT: 80-100km) on short time scales. Coupled with a linear approximation to the latitudinal structure of atmospheric tides, it is possible to extract time series of the diurnal and semidiurnal tides at various zonal wave numbers. The temporal variation of non-migrating (non-sun synchronous) components of the tides provide clues to their source mechanism. Non-linear interactions between tides and planetary waves and zonal asymmetries in tidal forcing are favoured mechanisms for the production of nonmigrating components. Although few clear linkages have been identified between planetary wave characteristics and tidal amplitude variations, this is likely due to the difficulty in separating wavenumber components using single station observations. ...
Concurrent operation of the MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) a... more Concurrent operation of the MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in Antarctica provides unprecedented global-scale coverage of the polar wind field in the mesosphere and lower thermosphere (MLT: 80-100km) on short time scales. Coupled with a linear approximation to the latitudinal structure of atmospheric tides, it is possible to extract time series of the diurnal and semidiurnal tides at various zonal wave numbers. Such an analysis has identified non-zero zonally symmetric (wavenumber zero) tides in the meridional wind. The continuity equation, cast in spherical polar coordinates, relates the magnitude and slope (with latitude) of the zonally averaged meridional wind to the change in the vertical mass flux with height. Meridional velocity variations associated with the zonally symmetric tides should therefore drive vertical motions whose magnitude can be obtained by integrating the vertical mass flux. In this study, diurnal ...
The Neyriz ophiolite occurs along the Zagros suture zone in SW Iran, and is part of a 3000-km obd... more The Neyriz ophiolite occurs along the Zagros suture zone in SW Iran, and is part of a 3000-km obduction belt thrusting over the edge of the Arabian continent during the late Cretaceous. This complex typically consists of altered dunites and peridotites, layered and massive gabbros, sheeted dykes and pillow lavas, and a thick sequence of radiolarites. Reflectance and emittance spectra of Neyriz ophiolite rock samples were measured in the laboratory and their spectra were used as endmembers in a spectral feature fitting (SFF) algorithm. Laboratory spectral reflectance measurements of field samples showed that in the visible through shortwave infrared (VNIR–SWIR) wavelength region the ultramafic and gabbroic rocks are characterized by ferrous-iron and Fe, MgOH spectral features, and the pillow lavas and radiolarites are characterized by spectral features of ferric-iron and AlOH. The laboratory spectral emittance spectra also revealed a wide wavelength range of SiO spectral features for the ophiolite rock units. After continuum removal of the spectra, the SFF classification method was applied to the VNIR+SWIR 9-band stack, and to the 11-band data set of SWIR and TIR data sets of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor, using field spectra as training sets for evaluating the potential of these data sets in discriminating ophiolite rock units. Output results were compared with the geological map of the area and field observations, and were assessed by the use of confusion matrices. The assessment showed, in terms of kappa coefficient, that the SFF classification method with continuum removal applied to the SWIR data achieved excellent results, which were distinctively better than those obtained using VNIR+SWIR data and TIR data alone.
Satellite-radiance data (Nimbus 5, 6; 80 km) and the MSIS-83 model have been used to prepare glob... more Satellite-radiance data (Nimbus 5, 6; 80 km) and the MSIS-83 model have been used to prepare global zonal-mean gradient winds (30-120 km) for the new CIRA-1986. Here these are supplemented by planetary-wave morphology from the same Nimbus data to provide local gradient winds-the zonal wind and the eddy portion of the meridional wind are calculated by this method. These data
During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was... more During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was situated between Darwin and Alice Springs, Australia. Observations made on 31 January 2006 by the Atmospheric Infrared Sounder instrument on the NASA Aqua satellite imaged ...
Between January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings require... more Between January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings required surgical intervention at this center. Nineteen patients had double aortic arch (group I); 13 patients had vascular ring consisting of right aortic arch, anomalous origin of the left subclavian artery, and ligamentum arteriosus (group II); eight patients had innominate artery compression (group III); and four patients had pulmonary artery sling (group IV). Three patients had complex congenital heart defect and died secondary to it and are excluded from the study. Follow-up was obtained on 31 patients (76%). The follow-up period ranged from 0.4 years to 10.9 years, with a mean of 3.6 years. Seventy percent of the overall group were asymptomatic, and 30% of patients continued to have upper and lower respiratory symptoms on late follow-up. One third of patients in groups I and II, who underwent surgical repair, continue to have symptoms. Patients who have persistent symptoms should be furt...
We report the first observations of polar mesosphere summer echoes (PMSE) above the high-latitude... more We report the first observations of polar mesosphere summer echoes (PMSE) above the high-latitude Southern Hemisphere (SH) station Davis, Antarctica (68.6°S, 78.0°E geographic; 74.6°S magnetic). Observations were obtained using a 55 MHz atmospheric radar, the first stage of which was commissioned late in the austral summer of 2002–2003. The radar commenced mesosphere observations with approximately 20 kW of transmitted power
MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in... more MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in Antarctica operate concurrently and provide unprecedented global-scale coverage of the polar wind field in the mesosphere and lower thermosphere (MLT: 80-100km) on short time scales. Coupled with a linear approximation to the latitudinal structure of atmospheric tides, it is possible to extract time series of the diurnal and semidiurnal tides at various zonal wave numbers. The temporal variation of non-migrating (non-sun synchronous) components of the tides provide clues to their source mechanism. Non-linear interactions between tides and planetary waves and zonal asymmetries in tidal forcing are favoured mechanisms for the production of nonmigrating components. Although few clear linkages have been identified between planetary wave characteristics and tidal amplitude variations, this is likely due to the difficulty in separating wavenumber components using single station observations. ...
Concurrent operation of the MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) a... more Concurrent operation of the MF radars at Davis (69S, 78E), Syowa (69S, 30E), Rothera (68S, 68W) and Scott Base (78S, 167E) in Antarctica provides unprecedented global-scale coverage of the polar wind field in the mesosphere and lower thermosphere (MLT: 80-100km) on short time scales. Coupled with a linear approximation to the latitudinal structure of atmospheric tides, it is possible to extract time series of the diurnal and semidiurnal tides at various zonal wave numbers. Such an analysis has identified non-zero zonally symmetric (wavenumber zero) tides in the meridional wind. The continuity equation, cast in spherical polar coordinates, relates the magnitude and slope (with latitude) of the zonally averaged meridional wind to the change in the vertical mass flux with height. Meridional velocity variations associated with the zonally symmetric tides should therefore drive vertical motions whose magnitude can be obtained by integrating the vertical mass flux. In this study, diurnal ...
The Neyriz ophiolite occurs along the Zagros suture zone in SW Iran, and is part of a 3000-km obd... more The Neyriz ophiolite occurs along the Zagros suture zone in SW Iran, and is part of a 3000-km obduction belt thrusting over the edge of the Arabian continent during the late Cretaceous. This complex typically consists of altered dunites and peridotites, layered and massive gabbros, sheeted dykes and pillow lavas, and a thick sequence of radiolarites. Reflectance and emittance spectra of Neyriz ophiolite rock samples were measured in the laboratory and their spectra were used as endmembers in a spectral feature fitting (SFF) algorithm. Laboratory spectral reflectance measurements of field samples showed that in the visible through shortwave infrared (VNIR–SWIR) wavelength region the ultramafic and gabbroic rocks are characterized by ferrous-iron and Fe, MgOH spectral features, and the pillow lavas and radiolarites are characterized by spectral features of ferric-iron and AlOH. The laboratory spectral emittance spectra also revealed a wide wavelength range of SiO spectral features for the ophiolite rock units. After continuum removal of the spectra, the SFF classification method was applied to the VNIR+SWIR 9-band stack, and to the 11-band data set of SWIR and TIR data sets of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor, using field spectra as training sets for evaluating the potential of these data sets in discriminating ophiolite rock units. Output results were compared with the geological map of the area and field observations, and were assessed by the use of confusion matrices. The assessment showed, in terms of kappa coefficient, that the SFF classification method with continuum removal applied to the SWIR data achieved excellent results, which were distinctively better than those obtained using VNIR+SWIR data and TIR data alone.
Satellite-radiance data (Nimbus 5, 6; 80 km) and the MSIS-83 model have been used to prepare glob... more Satellite-radiance data (Nimbus 5, 6; 80 km) and the MSIS-83 model have been used to prepare global zonal-mean gradient winds (30-120 km) for the new CIRA-1986. Here these are supplemented by planetary-wave morphology from the same Nimbus data to provide local gradient winds-the zonal wind and the eddy portion of the meridional wind are calculated by this method. These data
During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was... more During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was situated between Darwin and Alice Springs, Australia. Observations made on 31 January 2006 by the Atmospheric Infrared Sounder instrument on the NASA Aqua satellite imaged ...
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