scholarly journals Statistical Features of the Quiet Sun in EUV

2001 ◽  
Vol 203 ◽  
pp. 416-418
Author(s):  
A. Pauluhn ◽  
S. K. Solanki ◽  
I. Rüedi ◽  
E. Landi ◽  
U. Schühle
Keyword(s):  
Lognormal Distribution ◽  
Distribution Functions ◽  
Spectral Lines ◽  
Emission Lines ◽  
Statistical Features ◽  
Frequency Distributions ◽  
Quiet Sun ◽  
Euv Emission ◽  
The Past ◽  
Radiance Distribution

Frequency distributions of the intensities of EUV emission lines in the quiet Sun have in the past usually been modelled using two Gaussians. Here we test this and other distribution functions against observed distributions with exceptional statistics. The data were obtained in a number of spectral lines observed with CDS and SUMER. We show that the frequency distribution of the radiance is best modelled by a lognormal distribution. The fact that the radiance distribution of the quiet Sun including the network and the intranetwork is better reproduced by a single lognormal distribution function than by two Gaussians suggests that the same heating processes are acting in both types of features.

Research of the motivation and long-term objectives of Bulgarian and Serbian students

2019 ◽  
Vol 27 (2) ◽  
Author(s):  
Mariana Borukova ◽  
Vladimir Kotev
Keyword(s):  
Comparative Analysis ◽  
Everyday Life ◽  
Educational Development ◽  
Variation Analysis ◽  
Frequency Distributions ◽  
The Past ◽  
The Everyday ◽  
The University ◽  
Personal Assessment

Education is an activity requiring lengthy efforts and perseverance, as well as skills for acquiring information and its creative usage. All this is based on prolonged motivation, directly related to the improvement of the educational development and the consecutive professional realization. Long-term objectives serve as coordinating terms leading to particular goals in the everyday life and thus, behaviour could be rationalized and directed in a longer prospective towards both the past and the future. The aim of the present study is to survey the opinion and personal assessment of the long-term motivation of students from NSA “Vassil Levski”, Sofia and students from Nish, Serbia. The research was conducted from November 2016 to May 2017. It was done among 96 students (45 fourth-year students at NSA and 51 students from the University in Nish). The students had to fill out a test consisting of 10 questions related to their personal assessment of their long-term motivation. The results of the study were processed mathematically and statistically by: variation analysis, relative share, comparative analysis of two independent samples and comparative analysis of the frequency distributions with χ² – the Pearson criterion.According to the generalized conclusions, a higher percentage of the Bulgarian students is directed towards long-term objectives and prospects than the percentage of the Serbian students. Women are more motivated in their long-term development than men but there are not statistically significant differences along all the questions. Athletes’ motivation is higher than the average one for the whole population. We believe, however, that the motivation changes in the course of the studies and we assume it is higher for the students who are about to graduate.

Measurement of Dysprosium Stark Width and the Electron Impact Width Parameter

2018 ◽  
Vol 73 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Jhonatha R. dos Santos ◽  
Jonas Jakutis Neto ◽  
N. Rodrigues ◽  
M.G. Destro ◽  
José W. Neri ◽  
...  
Keyword(s):  
Electron Density ◽  
Impact Parameter ◽  
Plasma Temperature ◽  
Spectral Lines ◽  
Emission Lines ◽  
Spectroscopic Methods ◽  
Species Concentration ◽  
The Impact ◽  
Stark Width

In this work, we suggest a methodology to determine the impact parameter for neutral dysprosium emission lines from the characterization of the plasma generated by laser ablation in a sealed chamber filled with argon. The procedure is a combination of known consistent spectroscopic methods for plasma temperature determination, electron density, and species concentration. With an electron density of 3.1 × 1018 cm–3 and temperature close to 104 K, we estimated the impact electron parameter for nine spectral lines of the neutral dysprosium atom. The gaps in the impact parameter data in the literature, mainly for heavy elements, stress the importance of the proposed method.

scholarly journals A nanoflare model of quiet Sun EUV emission

2006 ◽  
Vol 462 (1) ◽  
pp. 311-322 ◽  
Author(s):  
A. Pauluhn ◽  
S. K. Solanki
Keyword(s):  
Quiet Sun ◽  
Euv Emission

scholarly journals Twenty years of observations of PM 1-188: Its chemical abundances and extraordinary kinematics

2021 ◽  
Author(s):  
Miriam Peña ◽  
Liliana Hernández-Martínez ◽  
Francisco Ruiz-Escobedo
Keyword(s):  
Chemical Composition ◽  
Planetary Nebula ◽  
Central Star ◽  
Emission Lines ◽  
Type I ◽  
Chemical Abundances ◽  
Line Intensities ◽  
Physical Conditions ◽  
The Past ◽  
Spectrophotometric Data

Abstract The analysis of 20 years of spectrophotometric data of the double shell planetary nebula PM 1-188 is presented, aiming to determine the time evolution of the emission lines and the physical conditions of the nebula, as a consequence of the systematic fading of its [WC 10] central star whose brightness has declined by about 10 mag in the past 40 years. Our main results include that the [O iii], [O ii], [N ii] line intensities are increasing with time in the inner nebula as a consequence of an increase in electron temperature from 11 000 K in 2005 to more than 14 000 K in 2018, due to shocks. The intensity of the same lines are decreasing in the outer nebula, due to a decrease in temperature, from 13 000 K to 7000 K, in the same period. The chemical composition of the inner and outer shells was derived and they are similar. Both nebulae present subsolar O, S and Ar abundances, while they are He, N and Ne rich. For the outer nebula the values are 12+log He/H = 11.13 ± 0.05, 12+log O/H = 8.04 ± 0.04, 12+log N/H = 7.87 ± 0.06, 12+log S/H = 7.18 ± 0.10 and 12+log Ar = 5.33 ± 0.16. The O, S and Ar abundances are several times lower than the average values found in disc non-Type I PNe, and are reminiscent of some halo PNe. From high resolution spectra, an outflow in the N-S direction was found in the inner zone. Position-velocity diagrams show that the outflow expands at velocities in the −150 to 100 km s−1 range, and both shells have expansion velocities of about 40 km s−1.

Religiosity and Depression among a National Sample of Adolescents

2019 ◽  
Vol 34 (1) ◽  
Author(s):  
Alique Topalian ◽  
Keith A. King ◽  
Rebecca A. Vidourek
Keyword(s):  
Retrospective Analysis ◽  
Religious Beliefs ◽  
Adolescent Depression ◽  
Religious Involvement ◽  
National Sample ◽  
Demographic Characteristics ◽  
Protective Effects ◽  
Frequency Distributions ◽  
The Past ◽  
Religiosity And Depression

This study examined religiosity and adolescent depression through a retrospective analysis viadata from the 2012 National Survey on Drug Use and Health. A national sample of adolescents aged12-17 years (n = 17,399) served as the participants of this study. Demographic characteristics were deter-mined by conducting frequency distributions. Odds ratios were computed to determine whether past year(2012) MDE differed based on adolescent involvement in religiosity. Multivariable logistic regressionanalyses were computed to examine whether past year MDE differed based on adolescent involvement inreligiosity for males and for females. Findings indicated that 9.7% of adolescents had a Major DepressiveEpisode (MDE) within the past year. Males at highest risk were those who did not feel their religious be-liefs were an important part of their life or that it was important their friends share their religious beliefs.Females at highest risk were those who did not feel their religious beliefs influence their decisions or thatit was important that their friends share their religious beliefs. Such findings may indicate that certainaspects of religious involvement may provide protective effects against adolescent MDE.

Properties of Magnetic Features from the Analysis of Near-Infrared Spectral Lines

1994 ◽  
Vol 154 ◽  
pp. 393-405
Author(s):  
Sami K. Solanki
Keyword(s):  
Near Infrared ◽  
Velocity Structure ◽  
Spectral Lines ◽  
The Past ◽  
Diagnostic Potential ◽  
Theoretical Predictions ◽  
Infrared Spectral ◽  
Magnetic Features

An overview is given of the structure and the physics of magnetic features in solar plages, as derived from observations of near-infrared lines. First, the diagnostic potential of near-infrared lines is compared with that of lines in the visible and at 12 μm. Then, the results on the magnetic and velocity structure of magnetic features obtained from 1.5 μm lines are described, discussed and compared with results of observations in the visible and with theoretical predictions. Finally, the past and present achievements of near-infrared investigations of Zeeman-split lines are summarized.

scholarly journals Can We Expect More Extreme Precipitation on the Monthly Time Scale?

2006 ◽  
Vol 19 (4) ◽  
pp. 630-637 ◽  
Author(s):  
Rasmus E. Benestad
Keyword(s):  
Extreme Precipitation ◽  
Climate Model ◽  
Global Climate Model ◽  
Distribution Functions ◽  
Monthly Precipitation ◽  
High Latitudes ◽  
Assessment Report ◽  
The Past ◽  
Ipcc Report ◽  
Instrumental Records

Abstract The Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report states that instrumental records show an increase in precipitation by +0.5%–1% decade−1 in much of the Northern Hemisphere mid- and high latitudes and a decrease of −0.3% decade−1 over subtropical land areas. It has been postulated that these trends are associated with the enhanced levels of atmospheric CO2. In this context, it is natural to ask how continuing rising levels of CO2 may affect the climate in the future. The past IPCC reports have documented numerous studies where increased greenhouse gas concentrations have been prescribed in global climate model simulations. Now, new simulations with state-of-the-art climate models are becoming available for the next IPCC report [the Fourth Assessment Report (AR4)], and results from a number of these simulations are examined in order to determine whether they indicate a change in extreme precipitation on a monthly basis. The analysis involves a simple record–statistics framework and shows that the upper tails of the probability distribution functions for monthly precipitation are being stretched in the mid- and high latitudes where mean-level precipitation increases have already been reported in the past. In other words, values corresponding to extreme monthly precipitation in the past are, according to these results, becoming more frequent.

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