scholarly journals The Zanstra Temperatures Revisited

2003 ◽  
Vol 209 ◽  
pp. 246-246
Author(s):  
R. Gruenwald ◽  
S. M. Viegas
Keyword(s):  
Optical Depth ◽  
Careful Analysis ◽  
Depth Effect ◽  
Single Star ◽  
Line Intensity Ratio ◽  
Stellar Temperature ◽  
Stellar Temperatures ◽  
Lower Temperature ◽  
Lower Limits

The temperature of the central stars in planetary nebulae is generally obtained by the Zanstra method. This method provides two values for the temperature of a single star: one obtained from the H recombination lines, TZ(H), and another from the He recombination lines, TZ(He II). The ratio (ZR) of these two values can be different from unit, leading to the well-known “Zanstra discrepancy”. The discrepancy is higher for lower temperature stars and the method does not reproduce the high values of stellar temperatures suggested by stellar evolutionary models. In this work a careful analysis of the effect of the optical depth on the determination of the Zanstra temperature is made, using photoionization models. The effects due to deviations from a blackbody spectrum, as well as to the He abundance in the nebulae, are also discussed. We show, quantitatively, that the details of the distribution of the H and He II Zanstra temperatures are mainly explained by an optical depth effect; in particular, the fact that the discrepancy is larger for low stellar temperatures. The results also show that for high stellar temperatures both Zanstra temperatures underestimate the stellar temperature, even for high optical depths. The stellar temperature, as well as the optical depth, can be obtained from a plot of ZR vs. TZ(He II). Since for nebulae of very low optical depth and/or high stellar temperature this plot only provides lower limits for T*, we propose the use of the line intensity ratio He II/He I vs. TZ(He II) diagram for obtaining the stellar temperature, as well as the nebular optical depth. The results of this work has been published in ApJ 543, 889 (2000).

scholarly journals The Determination of Stellar Temperatures From Baron B. Harkányi to the Gaia Mission

2020 ◽  
Vol 51 (2) ◽  
pp. 152-161
Author(s):  
Kristóf Petrovay
Keyword(s):  
Surface Temperature ◽  
The Sun ◽  
150Th Anniversary ◽  
Stellar Temperature ◽  
History Of ◽  
Stellar Temperatures

The first determination of the surface temperature of stars other than the Sun is due to the Hungarian astrophysicist Béla Harkányi. Prompted by the recent unprecedented increase in the availability of stellar temperature estimates from Gaia, coinciding with the 150th anniversary of Harkányi’s birth, this article presents the life and work of this neglected, yet remarkable figure in the context of the history of stellar astrophysics.

A Rapid Method for Determination of Buprenorphine and Norbuprenorphine in Urine by UPLC-MS/MS

2020 ◽  
Vol 16 ◽  
Author(s):  
Aykut Kul ◽  
Murat Ozdemir ◽  
Selma Ozilhan ◽  
Olcay Sagirli
Keyword(s):  
Forensic Science ◽  
Rapid Method ◽  
Proficiency Testing ◽  
Mass Spectrometer ◽  
Illicit Market ◽  
Analysis Methods ◽  
Accuracy And Precision ◽  
Lower Limits

Background: Buprenorphine is quite common in the illicit market. Buprenorphine-containing drugs abuse is frequently encountered in patients. The analysis methods used to determine the abuse of buprenorphine and norbuprenorphine are important for forensic science. Buprenorphine is metabolized to norbuprenorphine by the liver. Objective: Therefore, the determination of buprenorphine and norbuprenorphine in urine is one of the methods to determine the abuse of buprenorphine. Methods: In this study, we have developed a precise, simple, and rapid ultra-performance liquid chromatographytandem mass spectrometer method for the determination of buprenorphine and norbuprenorphine simultaneously. Results: The developed method was validated in terms of selectivity and linearity, which was in the range of 9–1800 ng/mL for both buprenorphine and norbuprenorphine. The intra-assay and inter-assay accuracy and precision were found within acceptable limits of the EMA guideline. Lower limits of quantitation were 9 ng/mL for both buprenorphine and norbuprenorphine. Conclusion: The developed method was successfully applied for the determination of both analytes in the proficiency testing samples.

scholarly journals Recognition of hydrogen isotopomers by an open-cage fullerene

2013 ◽  
Vol 371 (1998) ◽  
pp. 20110629 ◽  
Author(s):  
Yasujiro Murata ◽  
Shih-Ching Chuang ◽  
Fumiyuki Tanabe ◽  
Michihisa Murata ◽  
Koichi Komatsu
Keyword(s):  
Equilibrium Constants ◽  
Equilibrium Mixture ◽  
Size Difference ◽  
Binding Affinities ◽  
Kinetic Isotope ◽  
Molecular Sizes ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Pressure Hydrogen

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H 2 /HD/D 2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H 2 /D 2 exchange that generated an equilibrium mixture of H 2 /HD/D 2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D 2 molecule generally binds stronger than H 2 because of its heavier mass; however, the affinity for H 2 becomes larger than D 2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H 2 /HD/D 2 release from open-cage fullerene, proving their relative escaping rates. D 2 was found to be the smallest and H 2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H 2 and D 2 , but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.

scholarly journals Lithium Observations in the Sun

1968 ◽  
Vol 1 ◽  
pp. 243-246
Author(s):  
Edith A. Müller
Keyword(s):  
Unknown Origin ◽  
Absorption Feature ◽  
The Sun ◽  
Degree Of Ionization ◽  
Lithium Abundance ◽  
Resonance Doublet ◽  
Lower Temperature ◽  
Central Depth ◽  
The Continuum

The determination of the lithium abundance in the solar atmosphere is essentially based on the LiI resonance doublet at λ 6707·761 and 6707·912 Å. These two lines form a very faint absorption feature, the central depth of the stronger component being of the order of 1% of the continuum. The violet component, which is also the stronger of the two, occurs near the red wing of a faint solar line of unknown origin, and the lines appear to be blended with other faint lines including possibly the doublet of the Li6 isotope (the isotopic shift being 0·160 Å). No other line of LiI has been detected in the Fraunhofer spectum of the undisturbed solar disk. This is nothing surprising, because practically all lithium is expected to be ionized in the photosphere on account of its low ionization potential (Xion = 5·37 e.v.). In sunspot spectra the lower temperature reduces the degree of ionization of lithium and causes a strengthening of the LiI lines. In fact, the LiI resonance lines which appear as a very faint absorption feature on disk spectra are about 50 times stronger in spot spectra. Furthermore, the very weak feature at λ 6103·6 Å was identified by Dubov (1964) and by Schmahl and Schröter (1965) as due to the 2s 2S–3d 2D transition of LiI. Both the resonance doublet and the faint feature at 6103·6 Å have been used by the above-mentioned authors to derive the lithium abundance in spots.

scholarly journals Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO

2010 ◽  
Vol 10 (4) ◽  
pp. 1953-1967 ◽  
Author(s):  
S. Peyridieu ◽  
A. Chédin ◽  
D. Tanré ◽  
V. Capelle ◽  
C. Pierangelo ◽  
...  
Keyword(s):  
Optical Depth ◽  
North Atlantic ◽  
Western Indian Ocean ◽  
Saharan Dust ◽  
Orthogonal Polarization ◽  
Dust Layer ◽  
The North ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Good Agreement

Abstract. Monthly mean infrared (10 μm) dust layer aerosol optical depth (AOD) and mean altitude are simultaneously retrieved over the tropics (30° S–30° N) from almost seven years of Atmospheric Infrared Sounder (AIRS) observations covering the period January 2003 to September 2009. The method developed relies on the construction of look-up-tables computed for a large selection of atmospheric situations and follows two main steps: first, determination of the observed atmospheric thermodynamic situation and, second, determination of the dust properties. A very good agreement is found between AIRS-retrieved AODs and visible optical depths from the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua) during the main (summer) dust season, in particular for three regions of the tropical North Atlantic and one region of the north-western Indian Ocean. Outside this season, differences are mostly due to the sensitivity of MODIS to aerosol species other than dust and to the more specific sensitivity of AIRS to the dust coarse mode. AIRS-retrieved dust layer mean altitudes are compared to the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP/CALIPSO) aerosol mean layer altitude for the period June 2006 to June 2009. Results for a region of the north tropical Atlantic downwind of the Sahara show a good agreement between the two products (σ≈360 m). Differences observed in the peak-to-trough seasonal amplitude, smaller from AIRS, are principally attributed to the large difference in spatial sampling of the two instruments. They also come from the intrinsic limit in sensitivity of the passive infrared sounders for low altitudes. These results demonstrate the capability of high resolution infrared sounders to measure not only dust aerosol AOD but also the mean dust layer altitude.

scholarly journals Validation and Implementation of a Diagnostic Algorithm for DNA Detection ofBordetella pertussis,B. parapertussis, andB. holmesiiin a Pediatric Referral Hospital in Barcelona, Spain

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Ana Valero-Rello ◽  
Desiree Henares ◽  
Lesly Acosta ◽  
Mireia Jane ◽  
Iolanda Jordan ◽  
...  
Keyword(s):  
Internal Control ◽  
Whooping Cough ◽  
Diagnostic Algorithm ◽  
Clinical Samples ◽  
Analytical Validation ◽  
Content Type ◽  
Detection And Identification ◽  
Ofbordetella Pertussis ◽  
Lower Limits

ABSTRACTThis study aimed to validate a comprehensive diagnostic protocol based on real-time PCR for the rapid detection and identification ofBordetella pertussis,Bordetella parapertussis, andBordetella holmesii, as well as its implementation in the diagnostic routine of a reference children’s hospital. The new algorithm included a triplex quantitative PCR (qPCR) targeting IS481gene (inB. pertussis,B. holmesii, and someBordetella bronchisepticastrains), pIS1001(B. parapertussis-specific) andrnaseP as the human internal control. Two confirmatory singleplex tests forB. pertussis(ptxA-Pr) andB. holmesii(hIS1001) were performed if IS481was positive. Analytical validation included determination of linear range, linearity, efficiency, precision, sensitivity, and a reference panel with clinical samples. Once validated, the new algorithm was prospectively implemented in children with clinical suspicion of whooping cough presenting to Hospital Sant Joan de Deu (Barcelona, Spain) over 12 months. Lower limits of detection obtained were 4.4, 13.9, and 27.3 genomic equivalents/ml of sample for IS481(onB. pertussis), pIS1001and hIS1001, and 777.9 forptxA-Pr. qPCR efficiencies ranged from 86.0% to 96.9%. Intra- and interassay variabilities were <3% and <5%, respectively. Among 566 samples analyzed,B. pertussis,B. holmesii, andB. parapertussiswere detected in 11.1%, 0.9% (only in females >4 years old), and 0.2% of samples, respectively. The new algorithm proved to be a useful microbiological diagnostic tool for whooping cough, demonstrating a low rate of other non-pertussisBordetellaspecies in our surveilled area.

scholarly journals Gender problems in newborns: social, medical and legal aspects

2019 ◽  
Vol 64 (3) ◽  
pp. 124-128
Author(s):  
G. N. Komkova ◽  
A. V. Basova
Keyword(s):  
Sexual Development ◽  
Developmental Disorders ◽  
Coming Of Age ◽  
Careful Analysis ◽  
Legal Regulation ◽  
Legal Aspects ◽  
Self Determination ◽  
Constitutional Principle ◽  
The Right

Objective of the study. To analyze the modern literature on the legal regulation of the determination of the sex of newborns with disturbances of sexual development in Russia and abroad, as well as the right of these children for self-determination of their sex upon coming of age. Material and methods. The review is based on the domestic and foreign literature published overthe past 7 years, including in Pubmed. Results. There were revealed the modern problems of the legal regulation of determining the sex of newborns with developmental disorders in the territory of the Russian Federation. Conclusion. The right to the sex self-determination of  the children born with impaired sexual development upon coming of  age requires careful analysis by medical experts, as from a legal point of view it contributes to a more complete implementation of the constitutional principle of equality regardless of gender and ensures human rights in accordance with their perception and attitude.

Sign in / Sign up

Export Citation Format

Share Document