scholarly journals The Study of δ Scuti Stars in The Transition Era from Ground-Based to Space Photometry

2004 ◽  
Vol 193 ◽  
pp. 560-563 ◽  
Author(s):  
Rafael Garrido ◽  
Ennio Poretti
Keyword(s):  
Direct Consequence ◽  
Frequency Resolution ◽  
Research Teams ◽  
The Past ◽  
Successful Launch ◽  
Target Characterization ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Selection Of ◽  
Observational Effort

The different research teams involved in the study of δ Sct stars have slightly changed their strategy in the past years. The observational effort to secure worldwide coverage of case studies has been continued, but the requirements have become more severe, especially about target characterization and frequency resolution.After the successful launch of the Canadian satellite MOST, which will be the pioneer of asteroseismology from space, the future missions are programmed to properly take into account the need for adequate frequency resolution: COROT will spent 30 and 150 d (additional and core programs, respectively) on the target, while EDDINGTON will spend up to 3yr. Such a requirement is a direct consequence of the observational results on δ Sct, γ Dor, SPB, and other stars obtained from ground. It should be noted that without these results (see Poretti 2000 for a review about δ Sct stars) the scientific background of the space missions would be much less defined and the risks of incomplete results (owing to inaccurate selection of targets, insufficient resolution, underestimate of the influence of the rotation) much higher.

scholarly journals Methodological Aspects in the Frequency Analysis of Multiperiodic δ Scuti Stars

1993 ◽  
Vol 137 ◽  
pp. 733-735
Author(s):  
L. Mantegazza ◽  
E. Poretti ◽  
E. Antonello ◽  
E. Riboni
Keyword(s):  
Time Allocation ◽  
Signal To Noise Ratio ◽  
Frequency Resolution ◽  
Data Sampling ◽  
The Sixties ◽  
Established Fact ◽  
Methodological Aspects ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Obvious Extension

At Merate Observatory the study of δ Sct stars began in the sixties and spectroscopie and photometric campaigns were continuously undertaken in order to clarify the controversial points. As an obvious extension of the research, the observation of δ Sct stars was proposed for telescope-time allocation at European Southern Observatory, in order to take advantage of the ESO facilities and of the considerably better sky of La Silla. We put in our observing programme δ Sct stars showing cycle-to-cycle variations and, possibly, an amplitude larger than 0.05 mag in order to have a better signal-to-noise ratio; they are listed in the table. It is important to notice that we always tried to collect a number of measurements as large as possible (from 1988 we collected more than 1000 measurements per star), because it is a well-established fact that periodicities withan amplitude of a few thousandths of magnitude can be present in δ Sct stars. Moreover, when several modes are excited, an adequate frequency resolution becomes necessary and, therefore, a sufficient time baseline is requested (Poretti and Mantegazza 1992). A poor data sampling also gives an apparent good fitting for several solutions, all leaving a small residual rms, and there is no possibility to choose among them: different authors can pick up different solutions, generating the conflicting interpretations often found in δ Sct star literature.

scholarly journals Observational asteroseismology of δ Scuti stars

1997 ◽  
Vol 181 ◽  
pp. 381-386
Author(s):  
M. Breger ◽  
N. Audard
Keyword(s):  
Frequency Resolution ◽  
Intensive Study ◽  
Quality Of Data ◽  
Specific Frequency ◽  
Scuti Star ◽  
Excitation Mechanisms ◽  
Delta Scuti ◽  
Scuti Stars ◽  
Δ Scuti Stars

Ground-based observational networks are now able to reliably detect more than 20 frequencies for individual δ Scuti stars. The ground-based Delta Scuti Network specializes in the intensive study of individual stars for several months with dedicated telescopes on different continents. With the new quantity and quality of data, the observational limit to extracting 50 or more frequencies in a single δ Scuti star is no longer determined only by the signal/noise ratio, but by the available frequency resolution.Recent results on the δ Scuti stars FG Vir and 4CVn are presented. 4CVn exhibits some of the characteristics of δ Scuti stars: some close spacings are observed, pulsations occur in specific frequency regions with relatively sharp borders, and show large amplitude variations. This presents an important asteroseismological diagnostic, and can help us to improve our understanding of for example rotation and excitation mechanisms.We also report a new Gamma Doradus variable with two excited g modes (HD 108100, F2V).

Integrated FAHP-VIKOR model for green supplier selection in a Nickle coating SME

2020 ◽  
pp. 133-139
Author(s):  
Sanatan Ratna ◽  
B Kumar
Keyword(s):  
Staff Training ◽  
Supplier Selection ◽  
Fuzzy Ahp ◽  
Research Work ◽  
Supplier Evaluation ◽  
Green Supplier Selection ◽  
The Past ◽  
Coating Industry ◽  
Sustainability Issue ◽  
Selection Of

In the past few decades, there has been lot of focus on the issue of sustainability. This has occurred due to the growing concerns related to climate change and the growing awareness about environmental concerns. Also, the competition at global level has led to the search for the most sustainable route in the industries. The current research work deals with the selection of green supplier in a Nickle coating industry based on certain weighted green attributes. For this purpose, a hybrid tool comprising of Fuzzy AHP (Fuzzy Analytical Hierarchy) and VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje) is used. The Fuzzy AHP is used for assigning proper weights to the selected criteria for supplier evaluation, while VIKOR is used for final supplier selection based on the weighted criteria. The three criterions for green supplier selection are, Ecological packaging, Corporate socio-environmental responsibility and Staff Training. The outcome of the integrated model may serve as a steppingstone to other SMEs in different sectors for selecting the most suitable supplier for addressing the sustainability issue.

Building Research Teams

2017 ◽  
Author(s):  
Ken Peach
Keyword(s):  
Common Goal ◽  
Research Teams ◽  
Building Research ◽  
The Past ◽  
Collective Activity ◽  
Research Administrators ◽  
Working Together ◽  
Common Goals ◽  
Almost All ◽  
Century Science

This chapter discusses the process of building research teams. Increasingly over the past three-quarters of a century, science has become a collective activity, with teams of tens, hundreds or even thousands of scientists, engineers and technicians working together on a common goal. Consequently, almost all research involves building, motivating and maintaining a research team. Even a theoretical group is likely to have one or two postdocs, graduate students and visitors, but research teams will, in addition, have engineers and technicians, as well as, possibly, research administrators. The chapter also addresses the importance of creating and maintaining a good team and team spirit, as large projects are assembled from a large number of small teams working on common goals, usually in a loose federated structure with some overall coordination and leadership.

Evidence-based Assessment

2010 ◽  
pp. 76-98
Author(s):  
John Hunsley ◽  
Eric J. Mash
Keyword(s):  
Decision Making ◽  
Clinical Assessment ◽  
Assessment Process ◽  
Evidence Based ◽  
The Past ◽  
Specific Assessment ◽  
The Many ◽  
Selection Of ◽  
Made In

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.

scholarly journals Standardizing human brain parcellations

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ross M. Lawrence ◽  
Eric W. Bridgeford ◽  
Patrick E. Myers ◽  
Ganesh C. Arvapalli ◽  
Sandhya C. Ramachandran ◽  
...  
Keyword(s):  
Human Brain ◽  
Coordinate Space ◽  
The Past ◽  
File Storage ◽  
Statistical Inferences ◽  
Standardized Protocol ◽  
Storage Format ◽  
Labeling Scheme ◽  
Selection Of ◽  
Brain Atlases

AbstractUsing brain atlases to localize regions of interest is a requirement for making neuroscientifically valid statistical inferences. These atlases, represented in volumetric or surface coordinate spaces, can describe brain topology from a variety of perspectives. Although many human brain atlases have circulated the field over the past fifty years, limited effort has been devoted to their standardization. Standardization can facilitate consistency and transparency with respect to orientation, resolution, labeling scheme, file storage format, and coordinate space designation. Our group has worked to consolidate an extensive selection of popular human brain atlases into a single, curated, open-source library, where they are stored following a standardized protocol with accompanying metadata, which can serve as the basis for future atlases. The repository containing the atlases, the specification, as well as relevant transformation functions is available in the neuroparc OSF registered repository or https://github.com/neurodata/neuroparc.

scholarly journals Analgesia for Sheep in Commercial Production: Where to Next?

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1127
Author(s):  
Alison Small ◽  
Andrew David Fisher ◽  
Caroline Lee ◽  
Ian Colditz
Keyword(s):  
Research Effort ◽  
Mitigation Strategies ◽  
Worth Living ◽  
Life Worth Living ◽  
The Past ◽  
Considerable Research ◽  
Husbandry Practices ◽  
Industry Practice ◽  
Successful Launch ◽  
Inflammatory Drugs

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

scholarly journals Luminosity of δ Scuti Stars After Hipparcos Satellite

1998 ◽  
Vol 11 (1) ◽  
pp. 567-567
Author(s):  
E. Antonello ◽  
L. Mantegazza ◽  
E. Poretti
Keyword(s):  
Globular Clusters ◽  
Rotational Velocity ◽  
High Amplitude ◽  
Empirical Dependence ◽  
Trigonometric Parallaxes ◽  
Nearby Stars ◽  
Observational Errors ◽  
Absolute Magnitudes ◽  
Scuti Stars ◽  
Δ Scuti Stars

The absolute magnitudes of δ Scuti stars derived from parallaxes measured by the Hipparcos satellite were compared with the previous estimates based on photometric uvby² indices, and significant differences were found which are related to photometric effects of metallicity and rotational velocity. A reliable calibration of Mv in terms of the photometric indices shall include an estimate of these effects. It is important also to take into account the possible presence of unresolved close companions in order to fully exploit the accuracy of Mv of nearby stars derived from the trigonometric parallaxes. The Mv of few bright SX Phe stars support the period-luminosity relation obtained with ground based observations of globular clusters, while it does not seem to confirm the empirical dependence of this relation on the metallicity. Some high amplitude δ Scuti stars with intermediate or normal metallicity and small and uncertain parallax have apparently a very low luminosity. Simulations of Mv determinations from observed parallaxes based on the discussion of observational errors by Lutz and Kelker (1973) have shown that the low luminosity could be an effect related to these errors.

scholarly journals Non-Adiabatic Seismic Study of The Thin Convective Envelope of δ Scuti Stars

2004 ◽  
Vol 193 ◽  
pp. 470-473
Author(s):  
M.-A. Dupret ◽  
A. Grigahcène ◽  
R. Garrido ◽  
J. Montalban ◽  
M. Gabriel ◽  
...  
Keyword(s):  
Instability Strip ◽  
Full Spectrum ◽  
Convective Envelope ◽  
Theoretical Predictions ◽  
Mode Stability ◽  
Different Color ◽  
Mixing Length Theory ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Phase Differences

AbstractFor δ Sct stars, the theoretical predictions of a non-adiabatic pulsation code are very dependent on the characteristics of the thin convective envelope of the models (Balona & Evers 1999). The treatment of the non-adiabatic interaction between convection and pulsation also has a significant impact on the results, particularly near the red edge of the instability strip. The non-adiabatic theoretical predictions can be tested upon observations by comparing them to the amplitude ratios and phase differences as observed in different color passbands (Dupret et al. 2003). In the first part of this paper, we compare the results obtained by adopting different treatments of convection in the interior and atmosphere models: mixing-length theory (MLT) and full spectrum of turbulence (FST) (Canuto et al. 1996, CGM). In the second part, we examine the problem of the interaction between convection and pulsation and compare the mode stability obtained with and without including time-dependent convection in our non-adiabatic code.

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