MASERS: A Python package for statistical equilibrium calculations applied to masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 13-16
Author(s):  
R. van Rooyen ◽  
D. J. van der Walt
Keyword(s):  
Chemical Composition ◽  
Open Source ◽  
Energy Levels ◽  
Matrix Inversion ◽  
Statistical Equilibrium ◽  
Escape Probability ◽  
Physical Conditions ◽  
Equilibrium Calculations ◽  
Python Package ◽  
Inversion Calculation

AbstractThe study of astrophysical maser formation provides a useful probe of the chemical composition and physical conditions of the sources they are observed in. This exploration requires continuously solving the SE equations for the populations of the energy levels in search of conditions that will produce an inversion. After evaluation of available implementations applying the Escape Probability approximation, the masers solver was developed to provide an efficient and robust matrix inversion calculation. This open source package is hosted at https://bitbucket.org/ruby_van_rooyen/masers.

scholarly journals Chemical Composition in the Envelopes of Different WR Subtypes

1991 ◽  
Vol 143 ◽  
pp. 75-80 ◽  
Author(s):  
T. Nugis
Keyword(s):  
Chemical Composition ◽  
Reaction Rate ◽  
Energy Levels ◽  
Statistical Equilibrium ◽  
Equilibrium Equations ◽  
Line Intensities ◽  
Independent Information ◽  
Theoretical Line ◽  
Model Independent ◽  
The Mean

Valuable model-independent information about the chemical composition of WR stars can be obtained by using lines of different ions arising at transitions between highly excited energy levels. We determine the abundances of He, H, C, N, O using theoretical line intensities obtained by solving statistical equilibrium equations for level populations for different subtype WR envelope conditions.The chemical composition of WR stars strongly differs from the mean cosmic composition. In the case of WN stars nuclear processed CNO products of H-burning are revealed in the envelopes and He-burning products in the WC envelopes.The abundance of oxygen in WC stars differs from the predictions of recent evolutionary calculations which account for the new 12C(α,γ) 16O reaction rate.

scholarly journals SynBiopython: an open-source software library for Synthetic Biology

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jing Wui Yeoh ◽  
Neil Swainston ◽  
Peter Vegh ◽  
Valentin Zulkower ◽  
Pablo Carbonell ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Open Source ◽  
Open Source Software ◽  
Development Projects ◽  
Software Library ◽  
Current State ◽  
Starting Point ◽  
Common Problems ◽  
Data Tracking ◽  
Python Package

Abstract Advances in hardware automation in synthetic biology laboratories are not yet fully matched by those of their software counterparts. Such automated laboratories, now commonly called biofoundries, require software solutions that would help with many specialized tasks such as batch DNA design, sample and data tracking, and data analysis, among others. Typically, many of the challenges facing biofoundries are shared, yet there is frequent wheel-reinvention where many labs develop similar software solutions in parallel. In this article, we present the first attempt at creating a standardized, open-source Python package. A number of tools will be integrated and developed that we envisage will become the obvious starting point for software development projects within biofoundries globally. Specifically, we describe the current state of available software, present usage scenarios and case studies for common problems, and finally describe plans for future development. SynBiopython is publicly available at the following address: http://synbiopython.org.

scholarly journals QuakeMigrate: a Modular, Open-Source Python Package for Automatic Earthquake Detection and Location

2021 ◽  
Author(s):  
Tom Winder ◽  
Conor Bacon ◽  
Jonathan Smith ◽  
Thomas Hudson ◽  
Tim Greenfield ◽  
...  
Keyword(s):  
Open Source ◽  
Earthquake Detection ◽  
Python Package

scholarly journals AQUAMI: An open source Python package and GUI for the automatic quantitative analysis of morphologically complex multiphase materials

2017 ◽  
Vol 139 ◽  
pp. 320-329 ◽  
Author(s):  
Joshua Stuckner ◽  
Katherine Frei ◽  
Ian McCue ◽  
Michael J. Demkowicz ◽  
Mitsuhiro Murayama
Keyword(s):  
Quantitative Analysis ◽  
Open Source ◽  
Multiphase Materials ◽  
Python Package

scholarly journals DEBoost: A Python Library for Weighted Distance Ensembling in Machine Learning

2020 ◽  
Author(s):  
Wei Hao Khoong
Keyword(s):  
Machine Learning ◽  
Open Source ◽  
Data Preprocessing ◽  
Weighted Distance ◽  
Open Source License ◽  
Classification Tasks ◽  
Python Package

In this paper, we introduce deboost, a Python library devoted to weighted distance ensembling of predictions for regression and classification tasks. Its backbone resides on the scikit-learn library for default models and data preprocessing functions. It offers flexible choices of models for the ensemble as long as they contain the predict method, like the models available from scikit-learn. deboost is released under the MIT open-source license and can be downloaded from the Python Package Index (PyPI) at https://pypi.org/project/deboost. The source scripts are also available on a GitHub repository at https://github.com/weihao94/DEBoost.

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.

scholarly journals Modeling and analysis of medium-resolution integrated-light spectra of globular clusters in dwarf galaxies

2019 ◽  
Vol 14 (S351) ◽  
pp. 165-169
Author(s):  
Margarita E. Sharina ◽  
Vladislav V. Shimansky
Keyword(s):  
Chemical Composition ◽  
Globular Clusters ◽  
Dwarf Galaxies ◽  
Synthesis Method ◽  
Host Galaxies ◽  
Modeling And Analysis ◽  
Physical Conditions ◽  
Light Spectra ◽  
Medium Resolution ◽  
Key Points

AbstractThe study of ages, helium mass fraction (Y) and chemical composition of globular clusters in dwarf galaxies is important for understanding the physical conditions at the main evolutionary stages of the host galaxies and for constraining the build-up histories of large galaxies. We present the analysis of integrated-light spectra of 8 extragalactic and 20 Galactic globular clusters (GCs) using our population synthesis method. We calculate synthetic spectra of GCs according to the defined stellar mass functions using model atmospheres and stellar parameters ([Fe/H], Teff, and logg) set by theoretical isochrones. The main advantage of our method is the ability to determine not only chemical composition but also the age and mean Y in a cluster by modelling and analysis of Balmer absorption lines. The knowledge of Y and anomalies of light elements in star clusters is one of the key points for understanding the phenomenon of multiple stellar populations.

scholarly journals The impact of spectra quality on nebular abundances

2020 ◽  
Vol 495 (1) ◽  
pp. 1016-1034 ◽  
Author(s):  
Mónica Rodríguez
Keyword(s):  
Planetary Nebulae ◽  
The Other ◽  
Statistical Equilibrium ◽  
Emission Lines ◽  
Reference Spectrum ◽  
Equilibrium Equations ◽  
Chemical Abundances ◽  
Physical Conditions ◽  
Observational Errors ◽  
The Impact

ABSTRACT I explore the effects of observational errors on nebular chemical abundances using a sample of 179 optical spectra of 42 planetary nebulae (PNe) observed by different authors. The spectra are analysed in a homogeneous way to derive physical conditions and ionic and total abundances. The effects of recombination on the [O ii] and [N ii] emission lines are estimated by including the effective recombination coefficients in the statistical equilibrium equations that are solved for O+ and N+. The results are shown to be significantly different than those derived using previous approaches. The O+ abundances derived with the blue and red lines of [O ii] differ by up to a factor of 6, indicating that the relative intensities of lines widely separated in wavelength can be highly uncertain. In fact, the He ii lines in the range 4000–6800 Å imply that most of the spectra are bluer than expected. Scores are assigned to the spectra using different criteria and the spectrum with the highest score for each PN is taken as the reference spectrum. The differences between the abundances derived with the reference spectrum and those derived with the other spectra available for each object are used to estimate the 1σ observational uncertainties in the final abundances: 0.11 dex for O/H and Ar/H, 0.14 dex for N/H, Ne/H, and Cl/H, and 0.16 dex for S/H.

11. On the Chemical Composition of the Water composing the Clyde Sea Area

1888 ◽  
Vol 14 ◽  
pp. 422-427
Author(s):  
Adam Dickie
Keyword(s):  
Chemical Composition ◽  
Sea Water ◽  
Physical Conditions ◽  
Freshwater Stream ◽  
Marine Station ◽  
The Government ◽  
Government Grant ◽  
Clyde Sea ◽  
Sea Area

About the beginning of this year I was requested by a sub-committee of the Government Grant Committee* to determine some of the components of a series of samples of sea water, which were to be collected during the year at various parts and at different times in the Clyde sea area by the observers of the Scottish Marine Station. The collections were chiefly made under the immediate direction of Dr H. E. Mill. Since January, accordingly, I have been working at this, and have completed in all eighty-nine analyses, the results of which I now take the liberty of placing before this Society. There are various reasons why this paper should consist of little more than tables of results, one of which is that, having little or no experience in the science of oceanography, it would be presumptuous in me to draw conclusions from my results which would no doubt strike any one acquainted with that science at once. Another reason is that, though acquainted with some of the physical conditions under which the samples were taken, such as depth, temperature, place of collection, and date, I am quite ignorant of other conditions quite as important, if not more so, in my estimation, as, for instance, presence or absence of some freshwater stream near place of collection, state of tide, raiafall, 'c,—all conditions which would no doubt influence more or less materially the salinity of the water.

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