Échelle spectroscopy of the chemically peculiar star θ1 Ori F

ABSTRACT We analyse Échelle spectra of θ1 Ori F obtained by us on six nights unevenly distributed along 6 yr; we identify several hundred spectral lines and measure, for the first time, the star’s heliocentric radial velocity. We also collect and discuss previously published photometry of θ1 Ori F. We find that θ1 Ori F is a chemically peculiar (CP) star with overabundant silicon and phosphorus, and possibly other elements as well. From the singly ionized Fe, Cr and Ti lines we estimate its spectral type to be between B7 and B8. The radial velocity of θ1 Ori F is possibly marginally variable, with an average of 24 ± 4.2 km s−1 (standard deviation), in good agreement with the mean radial velocity of the Orion Nebula Cluster members, and about 5 km s−1 smaller than the average of the other Trapezium components. We cast doubt on the coeval nature of this star relative to the other Trapezium components, and present arguments that almost certainly exclude its membership to the Orion Trapezium. θ1 Ori F turns out to be enigmatic in several respects, and is probably an important link for understanding the evolutionary stage at which the CP phenomenon sets on.

Download Full-text

The Chemical Composition of S-Cepheids and Double-Mode Cepheids

International Astronomical Union Colloquium ◽

10.1017/s0252921100037465 ◽

1995 ◽

Vol 155 ◽

pp. 353-354

Author(s):

I.A. Usenko ◽

V.V. Kovtjukh ◽

S.M. Andrievsky ◽

V.G. Klochkova ◽

G.A. Galazutdinov

Keyword(s):

Radial Velocity ◽

Small Amplitude ◽

Theoretical Calculations ◽

The Other ◽

Evolutionary Status ◽

Helium Abundance ◽

Early Type ◽

Instability Strip ◽

First Time ◽

High Overtone

The main aim of this work is to consider the evolutionary status of s-Cepheids (SC), - small-amplitude Cepheids with smooth sinusoidal light, colour and radial velocity curves. The unusual character of these objects could be explained in two ways: (1) SCs are crossing the Cepheid instability strip for the first time and they are first (or high) overtone pulsators (Efremov 1970); (2) SCs have close early-type companions, which affect gravitationally the Cepheid He II zone. Such an effect can decrease the Cepheid pulsational activity (Lloyd Evans, 1968).According to theoretical calculations, low helium abundance in Cepheid atmospheres, which are crossing the instability strip for the first time, could produce small-amplitude oscillations. On the other hand, double-mode Cepheids (DMC) show oscillations with two (or three) periods: fundamental with large-amplitude asymmetrical light, colour and radial velocity curves, and first overtone with smooth sinusoidal small-amplitude ones. Nevertheless, detailed spectral and photometric investigations permit the detection of companions for the brightest SCs, and support the second hypothesis.

Download Full-text

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

Archives of Natural History ◽

10.3366/anh.2012.0091 ◽

2012 ◽

Vol 39 (2) ◽

pp. 217-233 ◽

Cited By ~ 4

Author(s):

J. David Archibald

Keyword(s):

Fossil Record ◽

Evolutionary Biology ◽

Phylogenetic Trees ◽

Charles Darwin ◽

The Other ◽

Charles Lyell ◽

Single Origin ◽

Molecular Studies ◽

Richard Owen ◽

First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

Download Full-text

Sphagnum mosses (Sphagnaceae, Bryophyta) of mires Chefandzar and Masota in North Ossetia (Caucasus)

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2018.52.2.455 ◽

2018 ◽

Vol 52 (2) ◽

pp. 455-462 ◽

Cited By ~ 2

Author(s):

G. Ya. Doroshina ◽

I. A. Nikolajev

Keyword(s):

Plant Communities ◽

The Other ◽

North Caucasus ◽

Sphagnum Mosses ◽

Greater Caucasus ◽

The North ◽

First Time ◽

North Ossetia

Sphagnum mires on the Greater Caucasus are rare, characterized by the presence of relict plant communities of glacial age and are in a stage of degradation. The study of Sphagnum of Chefandzar and Masota mires is carried out for the first time. Seven species of Sphagnum are recorded. Their distribution and frequency within the North Caucasus are analyzed. Sphagnum contortum, S. platyphyllum, S. russowii, S. squarrosum are recorded for the first time for the study area and for the flora of North Ossetia. The other mosses found in the study area are listed.

Download Full-text

An Epistemological Criticism of Social Entrepreneurship: Is Social Entrepreneurship a Sound Scientific Field of Research

10.31124/advance.7091927.v1 ◽

2018 ◽

Author(s):

Amir Forouharfar

Keyword(s):

Social Entrepreneurship ◽

Social Constructivism ◽

Social Epistemology ◽

American English ◽

Meta Analysis ◽

Research Question ◽

Knowledge Structure ◽

Scientific Field ◽

The Other ◽

First Time

The paper was shaped around the pivotal question: Is SE a sound and scientific field of research? The question has given a critical tone to the paper and has also helped to bring out some of the controversial debates in the realm of SE. The paper was organized under five main discussions to be able to provide a scientific answer to the research question: (1) is “social entrepreneurship” an oxymoron?, (2) the characteristics of SE knowledge, (3) sources of social entrepreneurship knowledge, (4) SE knowledge: structure and limitations and (5) contributing epistemology-making concepts for SE. Based on the sections, the study relied on the relevant philosophical schools of thought in Epistemology (e.g. Empiricism, Rationalism, Skepticism, Internalism vs. Externalism, Essentialism, Social Constructivism, Social Epistemology, etc.) to discuss these controversies around SE and proposes some solutions by reviewing SE literature. Also, to determine the governing linguistic discourse in the realm of SE, which was necessary for our discussion, Corpus of Contemporary American English (COCA) for the first time in SE studies was used. Further, through the study, SE buzzwords which constitute SE terminology were derived and introduced to help us narrowing down and converging the thoughts in this field and demarking the epistemological boundaries of SE. The originality of the paper on one hand lies in its pioneering discussions on SE epistemology and on the other hand in paving the way for a construction of sound epistemology for SE; therefore in many cases after preparing the philosophical ground for the discussions, it went beyond the prevalent SE literature through meta-analysis to discuss the cases which were raised. The results of the study verified previously claimed embryonic pre-paradigmatic phase in SE which was far from a sound and scientific knowledge, although the scholarly endeavors are the harbingers of such a possibility in the future which calls for further mature academic discussion and development of SE knowledge by the SE academia.

Download Full-text

A Nabatean port on the Red Sea: note on the pottery finds from al-Qusayr (al-Wajh, Saudi Arabia)

10.31338/uw.2083-537x.pam29.1.23 ◽

2020 ◽

Author(s):

Caroline Durand

Keyword(s):

Saudi Arabia ◽

19Th Century ◽

Red Sea ◽

Point Of View ◽

The Other ◽

Trade Routes ◽

Other Hand ◽

Roman Egypt ◽

Pottery Sherds ◽

First Time

Al-Qusayr is located 40 km south of modern al-Wajh, roughly 7 km from the eastern Red Sea shore. This site is known since the mid-19th century, when the explorer R. Burton described it for the first time, in particular the remains of a monumental building so-called al-Qasr. In March 2016, a new survey of the site was undertaken by the al-‘Ula–al-Wajh Survey Project. This survey focused not only on al-Qasr but also on the surrounding site corresponding to the ancient settlement. A surface collection of pottery sherds revealed a striking combination of Mediterranean and Egyptian imports on one hand, and of Nabataean productions on the other hand. This material is particularly homogeneous on the chronological point of view, suggesting a rather limited occupation period for the site. Attesting contacts between Mediterranean merchants, Roman Egypt and the Nabataean kingdom, these new data allow a complete reassessment of the importance of this locality in the Red Sea trade routes during antiquity.

Download Full-text

Status of Family Fissidentaceae in Gujarat

Cryptogam Biodiversity and Assessment ◽

10.21756/cba.v1i1.11022 ◽

2016 ◽

Vol 1 (1) ◽

Author(s):

D.G. Shah ◽

D.N. Mehta ◽

R.V. Gujar

Keyword(s):

Distinct Species ◽

The State ◽

The Other ◽

Land Plants ◽

Reproductive Structures ◽

The Family ◽

The Status ◽

Vegetative Characters ◽

First Time ◽

Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

Download Full-text

Sports News, Commentary and Interviews, From the Other Side: Journalists Seen Through the Eyes of Athletes

Communication & Sport ◽

10.1177/2167479521992371 ◽

2021 ◽

pp. 216747952199237

Author(s):

Ondřej Trunečka

Keyword(s):

Athletic Performance ◽

The Other ◽

Professional Athletes ◽

Main Role ◽

Cast Doubt ◽

The Media ◽

Sports News

This study explores how professional athletes perceive sports journalists and the role of the media. They acknowledge that communication with journalists is an essential part of their profession and appreciate the verified information, knowledge, and dutiful preparation. They consider the main role of media as monitorial. In some cases, they cast doubt on journalists’ ability to evaluate athletic performance accurately, and they are also critical of errors in interviews, however they acknowledgethat there are good, and possibly excellent journalists as well.

Download Full-text

Astrometric Radial Velocities From Hipparcos

Highlights of Astronomy ◽

10.1017/s153929960002219x ◽

1998 ◽

Vol 11 (1) ◽

pp. 564-564

Author(s):

D. Dravins ◽

L. Lindegren ◽

S. Madsen ◽

J. Holmberg

Keyword(s):

Radial Velocity ◽

High Precision ◽

Radial Velocities ◽

Radial Motion ◽

Spectral Lines ◽

Parallel Program ◽

Stellar Surface ◽

Space Astrometry ◽

Stellar Motion ◽

Surface Convection

Abstract Space astrometry now permits accurate determinations of stellar radial motion, without using spectroscopy. Although the feasibility of deducing astrometric radial velocities from geometric projection effects was realized already by Schlesinger (1917), only with Hipparcos has it become practical. Such a program has now been carried out for the moving clusters of Ursa Major, Hyades, and Coma Berenices. Realized inaccuracies reach about 300 m/s (Dravins et al. 1997). Discrepancies between astrometric and spectroscopic radial velocities reveal effects (other than stellar motion) that affect wavelength positions of spectral lines. Such are caused by stellar surface convection, and by gravitational redshifts. A parallel program (Gullberg & Dravins 1997) is analyzing high-precision spectroscopic radial velocities for different spectral lines in these stars, using the ELODIE radial-velocity instrument atHaute-Provence.

Download Full-text

Kinematics of Disk Stars in the Solar Neighbourhood

Highlights of Astronomy ◽

10.1017/s1539299600022310 ◽

1998 ◽

Vol 11 (1) ◽

pp. 574-574

Author(s):

A.E. Gómez ◽

S. Grenier ◽

S. Udry ◽

M. Haywood ◽

V. Sabas ◽

...

Keyword(s):

Dispersion Relation ◽

Radial Velocity ◽

Velocity Dispersion ◽

Tangential Velocity ◽

Thin Disk ◽

The Other ◽

Proper Motions ◽

Velocity Data ◽

Kinematic Data ◽

Radial Velocity Data

Using Hipparcos parallaxes and proper motions together with radial velocity data and individual ages estimated from isochones, the velocity ellipsoid has been determined as a function of age. On the basis of the available kinematic data two different samples were considered: a first one (7789 stars) for which only tangential velocities were calculated and a second one containing 3104 stars with available U, V and W velocity components and total velocities ≤ 65 km.s-1. The main conclusions are: -Mixing is not complete at about 0.8-1 Gyr. -The shape of the velocity ellipsoid changes with time getting rounder from σu/σv/σ-w = 1/0.63/0.42 ± 0.04 at about 1 Gyr to1/0.7/0.62 ±0.04 at 4-5 Gyr. -The age-velocity-dispersion relation (from the sample with kinematical selection) rises to a maximum, thereafter remaining roughly constant; there is no dynamically significant evolution of the disk after about 4-5 Gyr. -Among the stars with solar metallicities and log(age) > 9.8 two groups are identified: one has typical thin disk characteristics, the other is older than 10 Gyr and lags the LSR at about 40 km.s-1 . -The variation of the tangential velocity with age(without selection on the tangential velocity) shows a discontinuity at about 10 Gyr, which may be attributed to stars typically of the thick disk populations for ages > 10 Gyr.

Download Full-text

First Report of blaNDM-1 Bearing IncX3 Plasmid in Clinically Isolated ST11 Klebsiella pneumoniae from Pakistan

Microorganisms ◽

10.3390/microorganisms9050951 ◽

2021 ◽

Vol 9 (5) ◽

pp. 951

Author(s):

Hazrat Bilal ◽

Gaojian Zhang ◽

Tayyab Rehman ◽

Jianxion Han ◽

Sabir Khan ◽

...

Keyword(s):

Sequence Type ◽

The Other ◽

High Rate ◽

Antibiotics Resistance ◽

New Delhi ◽

Molecular Type ◽

Plasmid Analysis ◽

First Time ◽

Encoding Genes ◽

Sequence Types

The New Delhi Metallo-β-lactamase (NDM) is among the most threatening forms of carbapenemases produced by K. pneumoniae, well-known to cause severe worldwide infections. The molecular epidemiology of blaNDM-1-harboring K. pneumoniae is not well elucidated in Pakistan. Herein, we aim to determine the antibiotics-resistance profile, genes type, molecular type, and plasmid analysis of 125 clinically isolated K. pneumoniae strains from urine samples during July 2018 to January 2019 in Pakistan. A total of 34 (27.2%) K. pneumoniae isolates were carbapenemases producers, and 23 (18.4%) harbored the blaNDM-1 gene. The other carbapenemases encoding genes, i.e., blaIMP-1 (7.2%), blaVIM-1 (3.2%), and blaOXA-48 (2.4%) were also detected. The Multi Locus Sequence Typing (MLST) results revealed that all blaNDM-1-harboring isolates were ST11. The other sequence types detected were ST1, ST37, and ST105. The cluster analysis of Xbal Pulsed Field Gel Electrophoresis (PFGE) revealed variation amongst the clusters of the identical sequence type isolates. The blaNDM-1 gene in all of the isolates was located on a 45-kb IncX3 plasmid, successfully transconjugated. For the first time, blaNDM-1-bearing IncX3 plasmids were identified from Pakistan, and this might be a new primary vehicle for disseminating blaNDM-1 in Enterobacteriaceae as it has a high rate of transferability.

Download Full-text