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showing 10 items of 4384 documents
Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452
2012
International audience; Context. Be stars are rapidly rotating stars with a circumstellar decretion disk. They usually undergo pressure and/or gravity pulsation modes excited by the κ-mechanism, i.e. an effect of the opacity of iron-peak elements in the envelope of the star. In the Milky Way, p-modes are observed in stars that are hotter than or equal to the B3 spectral type, while g-modes are observed at the B2 spectral type and cooler. Aims. We observed a B0IVe star, HD 51452, with the high-precision, high-cadence photometric CoRoT satellite and high-resolution, ground-based HARPS and SOPHIE spectrographs to study its pulsations in great detail. We also used the lower resolution spectra a…
High Energy Emission and its Variability in Young Stellar Objects
2019
Young stars show a variety of highly energetic phenomena, from accretion and outflow processes to hot coronal plasmas confined in their outer atmosphere, all regulated by the intense stellar magnetic fields. Many aspects on each of these phenomena are debated, but, most notably, their complex mutual interaction remains obscure. In this work I report how these phenomena are simultaneously responsible for the high-energy emission from young stars, with a special focus on the expected and observed variability in the X-ray band. Investigating variations in the X-ray emission from young stars allows us to pose constraints on flare and coronal plasma properties, coronal heating, accretion stream …
Activity-rotation relation in the young cluster h Per
2015
The activity-rotation relation in PMS stars is still an open issue. To bridge the gap between the well constrained case of MS stars and the puzzling case of very young PMS stars, we studied the activity-rotation relation in the young cluster h Persei. Because of its age (˜13 Myr) h Per contains both fast and slow rotators, allowing us therefore to test the different regimes of stellar dynamo. We analyzed a deep Chandra/ACIS-I observation to constrain the activity level of h Per members. Rotational periods were derived by tet{MorauxArtemenko2013}. From the comparison of the 1002 detected X-ray sources, and the 586 h Per members with measured rotational period, we obtained a final catalog of …
X-ray emission from the old CTTS MP Muscae
2007
We study the properties of X-ray emitting plasma of MP Mus, an old classical T Tauri star. XMM-Newton/RGS spectra allow us to measure the plasma electron density, which probes whether X-ray emission is produced in the accretion process. X-ray emission from MP Mus originates from high density cool plasma but a hot flaring component is also present, suggesting that both coronal magnetic activity and accretion contribute to the observed X-ray emission. From the soft part of the X-ray emission from MP Mus, mostly produced by plasma heated in the accretion shock, we derive the accretion parameters and the characteristics of the shock-heated plasma.
X-ray emission from an adolescent classical T Tauri star
2007
CSI 2264: Simultaneous optical and X-ray variability in the pre-main sequence stars of NGC 2264
2019
Context. Pre-main sequence stars are variable sources. In diskless stars this variability is mainly due to the rotational modulation of dark photospheric spots and active regions, as in main sequence stars even if associated with a stronger magnetic activity.Aims. We aim at analyzing the simultaneous optical and X-ray variability in these stars to unveil how the activity in the photosphere is connected with that in the corona, to identify the dominant surface magnetic activity, and to correlate our results with stellar properties, such as rotation and mass.Methods. We analyzed the simultaneous optical and X-ray variability in stars without inner disks (e.g., class III objects and stars with…
Leveraging Sport Sponsorship with Digital Marketing Communication : A Conceptual Model
2023
Despite the demonstrated importance of social media platforms in leveraging the effects of sport sponsorship, surprisingly few studies have investigated this issue. The current study aims to broaden the knowledge of how major corporations could apply their marketing strategies related to sport sponsorship and utilise social media and digital channels for leveraging activities to meet their corporate goals through sponsorship-related digital marketing and public relations (PR) communication. This conceptual paper will contribute to the understanding of how sport sponsorship could be leveraged in social media and discuss key factors for creating a desirable leveraging effect. The main outcome…
Pre-sleep arousal and sleep quality during the COVID-19 lockdown in Italy
2021
Abstract Objective The COVID-19 pandemic has strongly affected daily habits and psychological wellbeing, and many studies point to large modifications in several sleep and sleep-related domains. Nevertheless, pre-sleep arousal during the pandemic has been substantially overlooked. Since hyperarousal represents one of the main factors for the development and the perpetuation of chronic insomnia disorder, the assessment of variables associated with high levels of pre-sleep arousal during the pandemic is clinically relevant. The study aimed to assess the prevalence and predictors of perceived sleep quality and pre-sleep arousal in an Italian sample during the COVID-19 lockdown. Methods We used…
Työ, talous ja tunteet Kari Hotakaisen Ihmisen osassa
2013
Kari Hotakaisen menestysromaani Ihmisen osa (2009) käsittelee suomalaista nyky-yhteiskuntaa, ja sen keskeisiä teemoja ovat työssä ja taloudessa tapahtuneet muutokset. Tämän artikkelin tarkoituksena on selvittää, millaisia romaanin kuvaamat muutokset ovat. Huomiota kiinnitetään varsinkin siihen, miten muutokset vaikuttavat henkilöhahmojen tunteisiin ja kokemuksiin maailmasta. Ajatuksena on, että Ihmisen osa antaa fiktiiviset kasvot suomalaisessa yhteiskunnassa tapahtuvalle tunnerakenteen muutokselle. peerReviewed
Public relations and expectation theory : Introducing Relationship Expectation Theory (RET) for public relations
2021
Expectations provide organizations with information and cues about their stakeholders’ and publics’ values, interests, experiences, and knowledge. This chapter argues for a move that takes expectations beyond the current cursory level for different areas of public relations—reputation management, corporate responsibility, issues management, and legitimacy—toward explicit theoretical understanding and models for addressing expectations. The chapter introduces expectations as an intersecting phenomenon in public relations research and builds postulations for theorizing expectations in public relations by reviewing theories that address expectations in relationships, and by exploring different…