scholarly journals Characterization of the variability in the O+B eclipsing binary HD 165246

2021 ◽  
Vol 503 (1) ◽  
pp. 1124-1137
Author(s):  
C Johnston ◽  
N Aimar ◽  
M Abdul-Masih ◽  
D M Bowman ◽  
T R White ◽  
...  
Keyword(s):  
Binary Solution ◽  
Rotational Frequency ◽  
Primary Component ◽  
Data Set ◽  
Eclipsing Binary ◽  
Photometric Observations ◽  
Wide Range ◽  
Evolutionary Context ◽  
High Level

ABSTRACT O-stars are known to experience a wide range of variability mechanisms originating at both their surface and their near-core regions. Characterization and understanding of this variability and its potential causes are integral for evolutionary calculations. We use a new extensive high-resolution spectroscopic data set to characterize the variability observed in both the spectroscopic and space-based photometric observations of the O+B eclipsing binary HD 165246. We present an updated atmospheric and binary solution for the primary component, involving a high level of microturbulence ($13_{-1.3}^{+1.0}\,$ km s−1) and a mass of $M_1=23.7_{-1.4}^{+1.1}$ M⊙, placing it in a sparsely explored region of the Hertzsprung--Russell diagram. Furthermore, we deduce a rotational frequency of $0.690\pm 0.003\,$d−1 from the combined photometric and line-profile variability, implying that the primary rotates at 40 per cent of its critical Keplerian rotation rate. We discuss the potential explanations for the overall variability observed in this massive binary, and discuss its evolutionary context.

scholarly journals Using kites for 3-D mapping of gullies at decimetre-resolution over several square kilometres: a case study on the Kamech catchment, Tunisia

2018 ◽  
Vol 18 (6) ◽  
pp. 1567-1582 ◽  
Author(s):  
Denis Feurer ◽  
Olivier Planchon ◽  
Mohamed Amine El Maaoui ◽  
Abir Ben Slimane ◽  
Mohamed Rached Boussema ◽  
...  
Keyword(s):  
High Resolution ◽  
Aerial Photography ◽  
Airborne Lidar ◽  
Data Set ◽  
Topographic Data ◽  
Independent Field ◽  
Wide Range ◽  
Laser Systems ◽  
High Level

Abstract. Monitoring agricultural areas threatened by soil erosion often requires decimetre topographic information over areas of several square kilometres. Airborne lidar and remotely piloted aircraft system (RPAS) imagery have the ability to provide repeated decimetre-resolution and -accuracy digital elevation models (DEMs) covering these extents, which is unrealistic with ground surveys. However, various factors hamper the dissemination of these technologies in a wide range of situations, including local regulations for RPAS and the cost for airborne laser systems and medium-format RPAS imagery. The goal of this study is to investigate the ability of low-tech kite aerial photography to obtain DEMs with decimetre resolution and accuracy that permit 3-D descriptions of active gullying in cultivated areas of several square kilometres. To this end, we developed and assessed a two-step workflow. First, we used both heuristic experimental approaches in field and numerical simulations to determine the conditions that make a photogrammetric flight possible and effective over several square kilometres with a kite and a consumer-grade camera. Second, we mapped and characterised the entire gully system of a test catchment in 3-D. We showed numerically and experimentally that using a thin and light line for the kite is key for a complete 3-D coverage over several square kilometres. We thus obtained a decimetre-resolution DEM covering 3.18 km2 with a mean error and standard deviation of the error of +7 and 22 cm respectively, hence achieving decimetre accuracy. With this data set, we showed that high-resolution topographic data permit both the detection and characterisation of an entire gully system with a high level of detail and an overall accuracy of 74 % compared to an independent field survey. Kite aerial photography with simple but appropriate equipment is hence an alternative tool that has been proven to be valuable for surveying gullies with sub-metric details in a square-kilometre-scale catchment. This case study suggests that access to high-resolution topographic data on these scales can be given to the community, which may help facilitate a better understanding of gullying processes within a broader spectrum of conditions.

scholarly journals Characterization of Vancomycin-Resistant Enterococcus faecium Isolates from the United States and Their Susceptibility In Vitro to Dalfopristin-Quinupristin

1998 ◽  
Vol 42 (5) ◽  
pp. 1088-1092 ◽  
Author(s):  
G. M. Eliopoulos ◽  
C. B. Wennersten ◽  
H. S. Gold ◽  
T. Schülin ◽  
M. Souli ◽  
...  
Keyword(s):  
United States ◽  
Enterococcus Faecium ◽  
Multiple Drug Resistance ◽  
The United States ◽  
Multiple Drug ◽  
Data Set ◽  
Vancomycin Resistant ◽  
High Level

ABSTRACT In the course of clinical studies with the investigational streptogramin antimicrobial dalfopristin-quinupristin, isolates of vancomycin-resistant Enterococcus faecium were referred to our laboratory from across the United States. Seventy-two percent of the strains were of the VanA type, phenotypically and genotypically, while 28% were of the VanB type. High-level resistance to streptomycin or gentamicin was observed in 86 and 81%, respectively, of the VanA strains but in only 69 and 66%, respectively, of the VanB strains. These enterococci were resistant to ampicillin (MIC for 50% of the isolates tested [MIC50] and MIC90, 128 and 256 μg/ml, respectively) and to the other approved agents tested, with the exception of chloramphenicol (MIC90, 8 μg/ml) and novobiocin (MIC90, 1 μg/ml). Considering all of the isolates submitted, dalfopristin-quinupristin inhibited 86.4% of them at concentrations of ≤1 μg/ml and 95.1% of them at ≤2 μg/ml. However, for the data set comprised of only the first isolate submitted for each patient, 94.3% of the strains were inhibited at concentrations of ≤1 μg/ml and 98.9% were inhibited at concentrations of ≤2 μg/ml. Multiple drug resistance was very common among these isolates of vancomycin-resistant E. faecium, while dalfopristin-quinupristin inhibited the majority at concentrations that are likely to be clinically relevant.

scholarly journals Characterization of turbulence and validation of fine-scale parametrization in the Mediterranean Sea during BOUM experiment

2011 ◽  
Vol 8 (5) ◽  
pp. 8961-8998 ◽  
Author(s):  
Y. Cuypers ◽  
P. Bouruet-Aubertot ◽  
C. Marec ◽  
J.-L. Fuda
Keyword(s):  
Energy Dissipation ◽  
Mediterranean Sea ◽  
Fine Scale ◽  
Data Set ◽  
Mean Values ◽  
The Mediterranean ◽  
Microstructure Measurements ◽  
High Level ◽  
Anticyclonic Eddies

Abstract. One main purpose of BOUM experiment was to give evidence of the possible impact of submesoscale dynamics on biogeochemical cycles. To this aim physical as well as biogeochemical data were collected along a zonal transect through the western and eastern basins. Along this transect 3 day fixed point stations were performed within anticyclonic eddies during which microstructure measurements were collected over the first 100 m. We focus here on the characterization of turbulent mixing induced by internal wave breaking. The analysis of microstructure measurements revealed a high level of turbulence in the seasonal pycnocline and a moderate level below with energy dissipation mean values of the order of 10−6 W kg−1 and 10−8 W kg−1, respectively. Fine-scale parameterizations developed to mimic energy dissipation produced by internal wavebreaking were then tested against these direct measurements. Once validated a parameterization has been applied to infer energy dissipation and mixing over the whole data set, thus providing an overview over a latitudinal section of the Mediterranean sea. The results evidence a significant increase of dissipation at the top and base of eddies associated with strong near inertial waves. Vertical turbulent diffusivity is increased both in these regions and in the weakly stratified eddy core.

scholarly journals General characterization of regeneration in Aeolosoma viride

2018 ◽  
Author(s):  
Chiao-Ping Chen ◽  
Sheridan Ke-Wing Fok ◽  
Yu-Wen Hsieh ◽  
Cheng-Yi Chen ◽  
Fei-Man Hsu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Model Organisms ◽  
Regenerative Processes ◽  
Blastema Cell ◽  
Microtubule Inhibitor ◽  
Wide Range ◽  
Highly Correlated ◽  
High Level ◽  
Complete Regeneration

Regeneration has long attracted scientists for its potential to restore lost, damaged or aged tissues and organs. A wide range of studies have conducted on different model organisms on both cellular and molecular levels. Current evidences suggest that a variety of regenerative strategies are developed and used by different species, and their regenerative strategies are highly correlated to their reproductive methods. Our present work focused on the freshwater annelid Aeolosoma viride, which reproduces by paratonic fission and is capable of complete regeneration. We found out that A. viride can regenerate both anterior and posterior end, even with only 3 segments remained. This process is characterized by epimorphosis that involves large amount of cell proliferation which drives the formation of blastema. Cell proliferation and regeneration successful ratio were significantly decreased when treated with microtubule inhibitor taxol or Avi-tubulin dsRNA, which confirmed that cell proliferation served as a key event during regeneration. Together, our data described the regenerative processes of A. viride, which includes high level of cell proliferation and the formation of blastema. Furthermore, our findings demonstrated A. viride as a potential model for the study of regeneration.

Numerical Characterization of Aerodynamic Losses of Jet Arrays for Gas Turbine Applications

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Antonio Andreini ◽  
Riccardo Da Soghe
Keyword(s):  
Gas Turbine ◽  
Discharge Coefficient ◽  
Cooling System ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Department Of Energy ◽  
Data Set ◽  
Wide Range ◽  
Depth Analysis

Jet array is an arrangement typically used to cool several gas turbine parts. Some examples of such applications can be found in the impingement cooled region of gas turbine airfoils or in the turbine blade tip clearances control of large aero-engines. In order to correctly evaluate the impinging jet mass flow rate, the characterization of holes discharge coefficient is a compulsory activity. In this work, an aerodynamic analysis of jet arrays for active clearance control was performed; the aim was the definition of a correlation for the discharge coefficient (Cd) of a generic hole of the array. The data were taken from a set of CFD RANS simulations, in which the behavior of the cooling system was investigated over a wide range of fluid-dynamics conditions. Furthermore, several different holes arrangements were investigated in significant detail, with the aim of evaluating the influence of the hole spacing on the discharge coefficient distribution. Tests were conducted by varying the jet Reynolds number in a wide range of effective engine operative conditions (Re = 2000-12,000, Pressure- Ratio = 1.01-1.6). To point out the reliability of the CFD analysis, some comparisons with experimental data, measured at the Department of Energy Engineering of the University of Florence, were drawn. An in-depth analysis of the numerical data set has underlined the opportunity of an efficient reduction through the mass velocity ratio of hole and feeding pipe: the dependence of the discharge coefficients from this parameter is roughly logarithmic.

scholarly journals V772 Cas: an ellipsoidal HgMn star in an eclipsing binary

2020 ◽  
Vol 500 (2) ◽  
pp. 2577-2589
Author(s):  
O Kochukhov ◽  
C Johnston ◽  
J Labadie-Bartz ◽  
S Shetye ◽  
T A Ryabchikova ◽  
...  
Keyword(s):  
Brightness Variation ◽  
Primary Component ◽  
Eclipsing Binaries ◽  
High Resolution Spectroscopy ◽  
Eclipsing Binary ◽  
Fundamental Parameters ◽  
Chemically Peculiar ◽  
Photometric Observations ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars

ABSTRACT The late B-type star V772 Cas (HD 10260) was previously suspected to be a rare example of a magnetic chemically peculiar star in an eclipsing binary system. Photometric observations of this star obtained by the TESS satellite show clear eclipses with a period of 5.0137 d accompanied by a significant out-of-eclipse variation with the same period. High-resolution spectroscopy reveals V772 Cas to be an SB1 system, with the primary component rotating about a factor two slower than the orbital period and showing chemical peculiarities typical of non-magnetic HgMn chemically peculiar stars. This is only the third eclipsing HgMn star known and, owing to its brightness, is one of the very few eclipsing binaries with chemically peculiar components accessible to detailed follow-up studies. Taking advantage of the photometric and spectroscopic observations available for V772 Cas, we performed modelling of this system with the phoebe code. This analysis provided fundamental parameters of the components and demonstrated that the out-of-eclipse brightness variation is explained by the ellipsoidal shape of the evolved, asynchronously rotating primary. This is the first HgMn star for which such variability has been definitively identified.

scholarly journals NDACC harmonized formaldehyde time-series from 21 FTIR stations covering a wide range of column abundances

2018 ◽  
Author(s):  
Corinne Vigouroux ◽  
Carlos Augusto Bauer Aquino ◽  
Maïté Bauwens ◽  
Cornelis Becker ◽  
Thomas Blumenstock ◽  
...  
Keyword(s):  
Time Series ◽  
Transport Model ◽  
Limit Of Detection ◽  
Atmospheric Composition ◽  
Data Set ◽  
Satellite Validation ◽  
Spatial Coverage ◽  
Combining Data ◽  
Wide Range

Abstract. Among the more than twenty ground-based FTIR (Fourier Transform infrared) stations currently operating around the globe, only a few have provided formaldehyde (HCHO) total columns time-series until now. Although several independent studies have shown that the FTIR measurements can provide accurate and precise formaldehyde total columns, the spatial coverage has not been optimal for providing good diagnostics for satellite or model validation. Furthermore, these past studies used different retrieval settings, and biases as large as 50 % can be observed in the HCHO total columns depending on these retrieval choices, which is also a weakness for validation studies combining data from different ground-based stations. For the present work, the HCHO retrieval settings have been optimized based on experience gained from the past studies and have been applied consistently at the 21 participating stations, most of them are either part of the Network for the Detection of Atmospheric Composition Change (NDACC), or under consideration for membership. We provide the harmonized settings and a characterization of the HCHO FTIR products. Depending on the station, the systematic and random uncertainties of an individual HCHO total column measurement lie between 11 and 31 %; and between 1 and 11 × 1014  molec/cm2, respectively, with median values among all stations of 14 % and 2.6 × 1014 molec/cm2. This unprecedented harmonized formaldehyde data set from 21 ground-based FTIR stations is presented and its comparison to a global chemistry transport model shows its consistency, in absolute values as well as in seasonal cycles. The network covers very different concentration levels of formaldehyde, from very clean levels at the limit of detection (few 1013 molec/cm2) to highly polluted levels (7 × 1016 molec/cm2). Because the measurements can be made at any time during daylight, the diurnal cycle can be observed and is found to be significant at many stations. These HCHO time-series, some of them starting in the 1990's, are crucial for past and present satellite validation, and will be extended in the coming years for the next generation of satellite missions.

scholarly journals Applied Demography In Action: A Case Study of “Population Identification.”

2008 ◽  
Vol 35 (1) ◽  
pp. 133 ◽  
Author(s):  
David A. Swanson
Keyword(s):  
Nuclear Regulatory Commission ◽  
Nuclear Waste Repository ◽  
Graduate Studies ◽  
Wide Range ◽  
The Us ◽  
High Level Nuclear Waste ◽  
Regulatory Commission ◽  
High Level

This case study deals with a problem quite different than the typical one facing most applied demographers. It involves the identification of a “population” using a set of criteria established by a regulatory agency. Specifically, criteria established by the US Nuclear Regulatory Commission for purposes of Site Characterization of the High Level Nuclear Waste Repository proposed for Yucca Mountain, Nevada. Consistent with other recent studies, this one suggests that a wide range of skills may be needed in dealing with problems posed to applied demographers by clients and users in the 21st century. As such, budding applied demographers, especially those nearing completion of their graduate studies, should consider adopting a set of skills beyond traditional demography.

scholarly journals Numerical Characterization of Pressure Drop Across the Manifold of Turbine Casing Cooling System

2012 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Antonio Andreini
Keyword(s):  
Discharge Coefficient ◽  
Cooling System ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Diameter Ratio ◽  
Data Set ◽  
Wide Range ◽  
Depth Analysis ◽  
Length To Diameter Ratio

Array of jets is an arrangement typically used to cool several gas turbine parts. Some examples of such applications can be found in the impingement cooling systems of turbine blades and vanes or in the turbine blade tip clearances control of large aeroengines. In order to correctly evaluate the impinging jet mass flow rate, the characterization of holes discharge coefficient is a compulsory activity. In a previous work the authors have performed an aerodynamic analysis of different arrays of jets for active clearance control; the aim was the definition of a correlation for the discharge coefficient (Cd) of a generic hole of the array. The developed empirical correlation expresses the Cd of each hole as a function of the ratio between the hole and the manifold mass velocity and the local value of the pressure ratio. In its original form, the correlation does not take in to account the effect of the hole length to diameter ratio (t/d) so, in the present contribution, the authors report a study with the aim of evaluating the influence of such parameter on the discharge coefficient distribution. The data were taken from a set of CFD RANS simulations, in which the behaviour of the cooling system was investigated over a wide range of fluid-dynamics conditions (Pressure-Ratio = 1.01–1.6, t/d = 0.25–3). To point out the reliability of the CFD analysis, some comparisons with experimental data were drawn. An in depth analysis of the numerical data set has led to an improved correlation with a new term function of the hole length to diameter ratio.

scholarly journals Computational Characterization of Astrophysical Species: The Case of Noble Gas Hydride Cations

2021 ◽  
Vol 9 ◽  
Author(s):  
María Judit Montes de Oca-Estévez ◽  
Rita Prosmiti
Keyword(s):  
Spectroscopic Data ◽  
Noble Gas ◽  
Basis Sets ◽  
Spectroscopic Constants ◽  
Computational Studies ◽  
Future Studies ◽  
Wide Range ◽  
Vibrational Levels ◽  
High Level

Theoretical–computational studies together with recent astronomical observations have shown that under extreme conditions in the interstellar medium (ISM), complexes of noble gases may be formed. Such observations have generated a wide range of possibilities. In order to identify new species containing such atoms, the present study gathers spectroscopic data for noble gas hydride cations, NgH+ (Ng = He, Ne, Ar) from high-level ab initio quantum chemistry computations, aiming to contribute in understanding the chemical bonding and electron sharing in these systems. The interaction potentials are obtained from CCSD(T)/CBS and MRCI+Q calculations using large basis sets, and then employed to compute vibrational levels and molecular spectroscopic constants for all known stable isotopologues of ground state NgH+ cations. Comparisons with previously reported values available are discussed, indicating that the present data could serve as a benchmark for future studies on these systems and on higher-order cationic noble gas hydrides of astrophysical interest.

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