Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

scholarly journals Emission-line-profile variability as a contraint on the structure and dynamics of hot star winds

2003 ◽  
Vol 212 ◽  
pp. 168-169
Author(s):  
Luc Dessart ◽  
Stanley P. Owocki
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Theoretical Calculations ◽  
Line Center ◽  
Radiation Hydrodynamics ◽  
Velocity Scale ◽  
Centre Region ◽  
Lateral Extent ◽  
Emission Line Profile ◽  
Hot Star Winds

We present theoretical calculations of emission-line-profile variability (LPV), based on radiation hydrodynamics simulations of the infamous radiative instability of hot star winds. We demonstrate that spherically symmetric wind structures (shells) cannot account for the observed profile variability at line center. Hence, we resort to a model that breaks-up the wind volume into a number of independent star-centered cones. The essential approximation made here is that each of these cones can be described by a structure calculated with a one-dimensional (1d) radiation hydrodynamics model. Such pseudo-3d ‘patch’-method leads to a satisfactory reproduction of the fundamental characteristics of LPV observed in O-type and Wolf-Rayet star optical spectra: the low-level fluctuations in the profile centre region, a migration of variable sub-peaks from line center to edge, that mimics the underlying wind acceleration. Our method highlights the correlation between the velocity scale of profile sub-peaks at line center and the lateral extent of wind structures, while at line edge it reflects the intrinsic radial velocity dispersion of emitting clumps. However, our model fails to reproduce the increase in this characteristic velocity scale from line center to edge, which we believe is a shortcoming of our purely 1d hydrodynamics approach.

scholarly journals Oxygen Saturation of Hemoglobin in Healthy Children of 2- 14 Years at High Altitude in Nepal

2012 ◽  
Vol 10 (1) ◽  
pp. 30-33
Author(s):  
S Shrestha ◽  
S Shrestha ◽  
L Shrestha ◽  
N Bhandary
Keyword(s):  
Oxygen Saturation ◽  
High Altitude ◽  
Healthy Children ◽  
Older Children ◽  
Contributing Factors ◽  
Lower Altitude ◽  
Value Of Children ◽  
The Mean ◽  
The Difference ◽  
Different Altitudes

Background Individuals residing at higher altitude may have oxygen saturation of hemoglobin different to those living at lower altitude. # Objectives To find out the baseline value of SpO2 in healthy Nepali children (2-14 years) living permanently at high altitude using pulse oximeter and also to study the relation of SpO2 with age, sex and ethnicity. Methods A descriptive observational study was conducted at 4 different altitudes ranging from 2700 to 3800 m in Mustang district. The mean pulse oximery values at different altitudes were calculated and compared. Results One hundred six children were enrolled with the median age of 10 years. The mean SpO2 value of children permanently residing at altitude 2700m was 95.18%, at 2800m was 94.82%, at 3550m was 94.1% and 3800m was 93.1%.The difference in the SpO2 values at different altitude was statistically significant. No sex or age wise differences were noted on the mean SpO2 values in the study group. Conclusions The mean SpO2 values were higher than several other studies done in the altitude above 2500 meters. Enrollment of older children and the different ethnic background could be the contributing factors for the differences. KATHMANDU UNIVERSITY MEDICAL JOURNAL  VOL.10 | NO. 1 | ISSUE 37 | JAN - MAR 2012 | 40-43 DOI: http://dx.doi.org/10.3126/kumj.v10i1.6912

Weight loss and changes in body composition at high altitude

1984 ◽  
Vol 57 (5) ◽  
pp. 1580-1585 ◽  
Author(s):  
S. J. Boyer ◽  
F. D. Blume
Keyword(s):  
Weight Loss ◽  
Body Composition ◽  
High Altitude ◽  
Body Fat ◽  
Moderate Altitude ◽  
Fat Absorption ◽  
Base Camp ◽  
Extreme Altitude ◽  
Muscle Catabolism ◽  
The Mean

Little is known about weight loss and changes in body composition at extreme altitude. As part of the American Medical Research Expedition to Everest in 1981 we measured body weight, body fat, limb circumferences, dietary intake, 72-h stool fats, and 5-h urine xylose excretion at various altitudes on Caucasian and Sherpa expedition members. In Caucasians, loss of body fat accounted for 70.5% of the mean 1.9-kg weight loss during the approach march at moderate altitude but for only 27.2% of the mean 4.0-kg weight loss during residence above 5,400 m. There was a significant proportionate decrease in arm and leg circumferences during residence above 5,400 m (1.5 and 2.9 cm, respectively). On the other hand, Sherpas, who arrived in Base Camp with half as much body fat as members (9.1% vs. 18.4%), maintained weight and limb circumferences during residence above 5,400 m. Fat absorption decreased 48.5% in three subjects, and xylose excretion decreased 24.3% in six of seven subjects at 6,300 m relative to sea level. It appears that muscle catabolism and malabsorption contribute significantly to weight loss at high altitude. High percent body fat does not protect against loss of muscle tissue. Sherpas do not appear susceptible to some of the changes affecting Caucasians.

scholarly journals Tracking isotopic signatures of CO<sub>2</sub> at the high altitude site Jungfraujoch with laser spectroscopy: analytical improvements and representative results

2013 ◽  
Vol 6 (7) ◽  
pp. 1659-1671 ◽  
Author(s):  
P. Sturm ◽  
B. Tuzson ◽  
S. Henne ◽  
L. Emmenegger
Keyword(s):  
High Altitude ◽  
Isotope Ratios ◽  
Particle Dispersion ◽  
High Temporal Resolution ◽  
Research Station ◽  
Close Link ◽  
Diurnal Variability ◽  
Air Masses ◽  
The Mean ◽  
Δ13c And Δ18o

Abstract. We present the continuous data record of atmospheric CO2 isotopes measured by laser absorption spectroscopy for an almost four year period at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.), Switzerland. The mean annual cycles derived from data of December 2008 to September 2012 exhibit peak-to-peak amplitudes of 11.0 μmol mol−1 for CO2, 0.60‰ for δ13C and 0.81‰ for δ18O. The high temporal resolution of the measurements also allow us to capture variations on hourly and diurnal timescales. For CO2 the mean diurnal peak-to-peak amplitude is about 1 μmol mol−1 in spring, autumn and winter and about 2 μmol mol−1 in summer. The mean diurnal variability in the isotope ratios is largest during the summer months too, with an amplitude of about 0.1‰ both in the δ13C and δ18O, and a smaller or no discernible diurnal cycle during the other seasons. The day-to-day variability, however, is much larger and depends on the origin of the air masses arriving at Jungfraujoch. Backward Lagrangian particle dispersion model simulations revealed a close link between air composition and prevailing transport regimes and could be used to explain part of the observed variability in terms of transport history and influence region. A footprint clustering showed significantly different wintertime CO2, δ13C and δ18O values depending on the origin and surface residence times of the air masses. Several major updates on the instrument and the calibration procedures were performed in order to further improve the data quality. We describe the new measurement and calibration setup in detail and demonstrate the enhanced performance of the analyzer. A measurement precision of about 0.02‰ for both isotope ratios has been obtained for an averaging time of 10 min, while the accuracy was estimated to be 0.1‰, including the uncertainty of the calibration gases.

scholarly journals Tropical tropospheric ozone derived using Clear-Cloudy Pairs (CCP) of TOMS measurements

2003 ◽  
Vol 3 (3) ◽  
pp. 683-695 ◽  
Author(s):  
M. J. Newchurch ◽  
D. Sun ◽  
J. H. Kim ◽  
X. Liu
Keyword(s):  
High Altitude ◽  
Tropospheric Ozone ◽  
Total Ozone ◽  
Stratospheric Ozone ◽  
Lower Troposphere ◽  
Significant Difference ◽  
Retrieval Efficiency ◽  
The Mean ◽  
Retrieval Errors ◽  
Low Altitude

Abstract. Using TOMS total-ozone measurements over high-altitude cloud locations and nearby paired clear locations, we describe the Clear-Cloudy Pairs (CCP) method for deriving tropical tropospheric ozone. The high-altitude clouds are identified by measured 380 nm reflectivities greater than 80% and Temperature Humidity InfraRed (THIR) measured cloud-top pressures less than 200 hPa. To account for locations without high-altitude clouds, we apply a zonal sine fitting to the stratospheric ozone derived from available cloudy points, resulting in a wave-one amplitude of about 4 DU. THIR data is unavailable after November 1984, so we extend the CCP method by using a reflectivity threshold of 90% to identify high-altitude clouds and remove the influence of high-reflectivity-but-low-altitude clouds with a lowpass frequency filter. We correct ozone retrieval errors associated with clouds, and ozone retrieval errors due to sun glint and aerosols. Comparing CCP results with Southern Hemisphere ADditional OZonesondes (SHADOZ) tropospheric ozone indicates that CCP tropospheric ozone and ozonesonde measurements agree, on average, to within 3 ± 1 DU standard error of the mean. The most significant difference between CCP and ozonesonde tropospheric ozone can be explained by the low Total Ozone Mapping Spectrometer (TOMS) version-7 retrieval efficiency of ozone in the lower troposphere.

scholarly journals Hematological Parameters and Erythropoiesis Regulation of True Native Highlanders

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4448-4448
Author(s):  
Subhash Varma ◽  
Uday Yanamandra ◽  
Harikishan Senee ◽  
Srinivasa Bhattachar ◽  
Sushma Yanamandra ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
High Altitude ◽  
Serum Ferritin ◽  
Haemoglobin Concentration ◽  
High Serum ◽  
Haematological Parameters ◽  
Peripheral Oxygen Saturation ◽  
Study Population ◽  
The Mean ◽  
Serum Erythropoietin

Abstract Introduction: The haematological parameters, regulation of erythropoiesis, erythropoietin and body iron stores have been variably studied in dwellers and transient visitors from high altitude. Even in individuals born at high altitude, transient movements out of high altitude can significantly change these parameters. The role of this genetic adaption (reduced erythropoiesis) in Tibetans is well described (Moore LG et al, High Alt Med Biol 2001). There are scarce studies on true native highlanders and 'Ladakhi' populace from India which is geographically co-located to Tibet but of different ethnic origin (Wu TY et al, Zhongguo Ying Yong Sheng Li XueZaZhi. 2013). Objective: To study complete blood counts including red cell and platelet indices in native highlanders and influence of high altitude living on body iron stores and serum erythropoietin levels in true native highlanders. Methodology: True native highlanders in this study are defined as individuals born at altitudes above 11500ft with no descent to lower altitudes ever in their life. Baseline anthropometric data and peripheral oxygen saturations were collected. Haematological work up included total haemoglobin, haematocrit, total/ differential leucocyte count, platelets, red cell and platelet indices done by Sysmax® automated counter at Leh, Ladakh and serum erythropoietin/ ferritin levels at PGIMER, Chandigarh. A total of 1328 children were screened of which 402 children (stratified by age 4-17years) were identified as true native highlanders. Guardians of 12 children didn't consent for the haematological evaluation. Results: Study population included 197 males and 193 females. The mean age of study population was 127.58 + 39.64 months (range 35-254). The mean BMI was 18.7+2.5 kg/m2 (range 12.86-30.45). The mean peripheral oxygen saturation was 90.35 + 3.583 %. The haematological parameters of the study population are described in table 1. There was statistically significant difference between males and females in haemoglobin concentration, RBC count, haematocrit, platelet count and platelet distribution width (p<0.001). There was significant negative correlation between erythropoietin and haemoglobin concentration (r=0.718, p<0.001) (Fig 1A), serum ferritin and haemoglobin concentration(r:0.219, p=0.012) (Fig 1B). There was no significant correlation of peripheral oxygen saturation with haemoglobin concentration, serum ferritin or serum erythropoietin and of ferritin with EPO (Fig 2A-D). The prevalence of anaemia was 3.3% and polycythaemia was 17.2%. Low and high serum erythropoietin levels were seen in 18.8% and 7.5% respectively, low and high serum ferritin levels were seen in 23.9% and 2.2% respectively. The relation of haemoglobin groups with erythropoietin/ ferritin levels, ferritin groups with haemoglobin/ erythropoietin levels and erythropoietin groups with ferritin and haemoglobin levels are illustrated in Fig 3A-F. Conclusion: There is no relation of haemoglobin to the oxygen saturation of the individuals. The serum erythropoietin and ferritin levels do correlate with the haemoglobin levels but not with the oxygen saturation. A considerable proportion of individuals have low to normal erythropoietin and ferritin levels.Table 1.Haematological parameters in true native highlandersNMinimumMaximumMeanStd. DeviationHaemoglobin (g/dL)3604.5022.0014.69942.02690RBC count (x1012/L)357484.95.517Hematocrit (%)35718.5770.7040.60605.33243MCV (fL)36250.49101.0082.19247.45698MCH (pg)35712.2738.9229.76553.63519MCHC (g/dL)35621.1864.2036.31594.57284RDW.CV18311.2731.7015.17182.96735RDW_SD36235.6060.0043.88743.52161WBC (x109/L)3623430157407599.721990.329Lympho (%)362146036.128.104Mixed (%)3621175.353.421Neutro (%)362168458.349.013ALC (x109/L)362152.70.774ANC (x109/L)3621134.511.654PLT (x109/L)362701352376.86147.814PDW (%)3542.9057.1014.41075.56488MPV (fL)3543.3214.609.73401.63144PCT (%)183.031.47.4122.14302P.LCR (%)3485.2060.0026.85289.78539Ferritin (µg/L)1344.00192.0036.940334.05960EPO (mIU/L)80.78456.0019.902258.89438 Figure 1. Figure 1. Figure 2. Figure 2. Figure 3. Figure 3. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Chromosphere of β Cassiopeiae

1989 ◽  
Vol 111 ◽  
pp. 286-286
Author(s):  
Terry J. Teays ◽  
Edward G. Schmidt ◽  
Massimo Fracassini ◽  
Laura E. Pasinetti Fracassini
Keyword(s):  
Line Profile ◽  
High Dispersion ◽  
Emission Flux ◽  
Long Wavelength ◽  
Maximum Light ◽  
Classical Cepheids ◽  
Scuti Star ◽  
The Mean ◽  
Emission Core ◽  
Photometric Variation

AbstractWe have carried out high dispersion, long wavelength IUE observations and ground based photometry of the δ Scuti star, β Cas. Our ground based observations were used, together with the previous results of Antonello et al. (1986, I.B.V.S. 2958, 1986), to ensure that the IUE observations were correctly phased relative to the photometric variation. Fluxes for the emission core of the Mg II k line (2796 Å) were obtained from 23 ultraviolet spectra taken over several cycles in 1986 and 1987. The emission flux, if present, was measured with respect to the mean line profile of all of the spectra. Emission was present at phases between 0.4 and 0.5. This is in contrast to what has been observed for another δ Scuti star, ρ Pup, and for the classical Cepheids, where the emission appeared at maximum light.

scholarly journals Prediction of barometric pressures at high altitudes with the use of model atmospheres

1996 ◽  
Vol 81 (4) ◽  
pp. 1850-1854 ◽  
Author(s):  
John B. West
Keyword(s):  
High Altitude ◽  
Large Range ◽  
Civil Aviation ◽  
High Mountain ◽  
High Altitudes ◽  
Standard Atmosphere ◽  
The Past ◽  
The Mean ◽  
United States Standard ◽  
Proper Account

West, John B. Prediction of barometric pressures at high altitudes with the use of model atmospheres. J. Appl. Physiol. 81(4): 1850–1854, 1996.—It would be valuable to have model atmospheres that allow barometric pressures (Pb) to be predicted at high altitudes. Attempts to do this in the past using the International Civil Aviation Organization or United States Standard Atmosphere model have brought such models into disrepute because the predicted pressures at high altitudes are usually much too low. However, other model atmospheres have been developed by geophysicists. The critical variable is the change of air temperature with altitude, and, therefore, model atmospheres have been constructed for different latitudes and seasons of the year. These different models give a large range of pressures at a given altitude. For example, the maximum difference of pressure at an altitude of 9 km is from 206 to 248 Torr, i.e., ∼20%. However, the mean of the model atmospheres for latitude of 15° (in all seasons) and 30° (in the summer) predicts Pb at many locations of interest at high altitude very well, with predictions within 1%. The equation is Pb(Torr) = exp (6.63268 − 0.1112 h − 0.00149 h2), where h is the altitude in kilometers. The predictions are good because many high mountain sites are within 30° of the equator and also many studies are made during the summer. Other models should be used for latitudes of 45° and above. Model atmospheres have considerable value in predicting Pb at high altitude if proper account is taken of latitude and season of the year.

scholarly journals Stellar Rotation in the Young Cluster M17

2004 ◽  
Vol 215 ◽  
pp. 67-68
Author(s):  
Wenjin Huang ◽  
Douglas Gies ◽  
Philip Massey ◽  
Peter S. Conti
Keyword(s):  
Line Profile ◽  
Mean Value ◽  
Stellar Rotation ◽  
Ob Stars ◽  
The Mean ◽  
Young Clusters

We constructed line profile models for young OB stars in M17 using TLUSTY and SYNSPEC, including the effects of rotational flattening and gravitational darkening. The values of v sin i for 8 member stars (with spectral classifications O4.5 V to O9 V) range from 7 km s–1 to 168 km s–1. The mean value of v sin i (102 km s–1) is lower than expected for very young clusters.

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