Narrow structure in the coherent population trapping resonances in rubidium and Rayleigh scattering

The measurement of the coherent-population-trapping (CPT) resonances in uncoated Rb vacuum cells has shown that the shape of the resonances is different in different cells. In some cells the resonance has a complex shape - a narrow Lorentzian structure, which is not power broadened, superimposed on the power broadened CPT resonance. The results of the performed investigations on the fluorescence angular distribution are in agreement with the assumption that the narrow structure is a result of atom interaction with Rayleigh scattering light. The results are interesting for indication of the vacuum cleanness of the cells and building of magnetooptical sensors

Unfeasible body mass index and its association with low haemoglobin concentration: a correlation study among undergraduate medical students

Background: Low hemoglobin concentration and unfeasible body mass index adversely affect the health of people, consequently increasing morbidity and mortality among them. Hemoglobin concentration among individuals is associated with their body mass index. The prevalence of iron deficiency anemia is higher among underweight and overweight/obese people compared to those with normal BMI. Thus, the present study aimed to determine the correlation between hemoglobin concentration and BMI of undergraduate medical students.Methods: A cross-sectional study was carried out among 210 undergraduate medical students. Body mass index was calculated and hemoglobin estimation was done by Sahli's hemoglobinometer. Correlation between hemoglobin concentration and body mass index of subjects was assessed by Pearson’s correlation coefficient.Results: Underweight students had lowest mean hemoglobin concentration and the mean hemoglobin concentrations increased significantly (p<0.001) with increase in the BMI of subjects. A highly significant positive correlation (r=0.307, p<0.001) between BMI and hemoglobin concentration was observed. Further, significant positive correlation was observed among males (r=0.268, p=0.013), students with normal BMI (r=0.283, p=0.003) and overweight students (r=0.415, p=0.035) only.Conclusions: Hemoglobin concentration and BMI show a positive correlation, however this correlation tends to become negative in obese individuals. As both low hemoglobin concentration and unfeasible body mass index have detrimental effects on the health, diligent screening and management of both is essential for better outcome

Cirrus-cloud conditioned ratio of multiple-to-single backscatter atmospheric phase functions

Abstract The present work is related to LIDAR remote sensing of the atmosphere in the presence of cirrus clouds (CC) along the LIDAR line of sight (LOS), when the multiple-backscatter component of the LIDAR return may be essential. E. Eloranta has found analytical expressions of the multiple-backscatter components of different orders as containing the corresponding ratios of the multiple-to-single backscatter phase functions of the backward scattering medium. As a main purpose of this work, we estimated the above-mentioned ratios in cases of backscattering from air and CC, using accurate approximations of the single-scattering phase functions obtained by U. Wandinger. The results obtained show that the multiple-to-single backscatter phase function ratios for air are equal to unity, while for CCs they are quite near unity.</jats:p

Estimation of the double-scattering component of the lidar return from multi-component atmosphere

Abstract Estimation is performed based on a theory developed by Eloranta of the double-scattering contribution to the LIDAR return from a multi-component atmosphere that may contain not only molecular (gaseous) and aerosol fractions, but other compact aerosol objects as well, such as cirrus clouds or Saharan dust layers. It is shown that the relative double-scattering component of the LIDAR return may be approximately considered as a sum of the independent relative contributions of each of the atmospheric components. Then, using appropriate models, the contribution of each component of interest is evaluated as a function of the altitude, taking into account the scattering properties of the medium under consideration, the angular divergence and the wavelength of the sensing laser beam, and the angle of view of the receiving optical system. The results obtained outline the cases when either the double scattering is negligible or corrections are necessary for the multiple scattering effects.</jats:p