4,156 research outputs found
The dual dust chemistries of planetary nebulae with [WCL] central stars
The rather rare class of central stars of planetary nebulae that show very low-excitation Wolf–Rayet spectra has been a subject of great interest, particularly in the infrared, since its discovery in the late 1960s. Further peculiarities have been found with the advent of infrared spectroscopy from ISO. Notably, these objects simultaneously betray the presence of regions of carbon-rich and oxygen-rich dust chemistry. We compare and contrast complete ISO spectra between 2 and 200 μm of a sample of six [WC8] to [WC11] central stars, finding many similarities. Among this sample, one star provides strong evidence of quasi-periodic light variations, suggestive of a dust cloud orbiting in a plane from which we view the system
Self-compassion and physical health: Exploring the roles of perceived stress and health-promoting behaviors
Growing evidence indicates that self-compassion is associated with better physical health, but the pathways that mediate this relationship are not well understood. This study tested a serial mediation model that linked self-compassion, perceived stress, health behaviors, and a comprehensive index of physical health. A sample of 176 individuals completed an online survey posted on Amazon’s Mechanical Turk. Self-compassion had an indirect effect on physical health via both mediators as well as through the sequential pathway, suggesting that taking a kind, accepting and mindful stance toward one’s flaws and failures may have benefits for reducing stress and promoting health behaviors
Models of Star-Planet Magnetic Interaction
Magnetic interactions between a planet and its environment are known to lead
to phenomena such as aurorae and shocks in the solar system. The large number
of close-in exoplanets that were discovered triggered a renewed interest in
magnetic interactions in star-planet systems. Multiple other magnetic effects
were then unveiled, such as planet inflation or heating, planet migration,
planetary material escape, and even modification of the host star properties.
We review here the recent efforts in modelling and understanding magnetic
interactions between stars and planets in the context of compact systems. We
first provide simple estimates of the effects of magnetic interactions and then
detail analytical and numerical models for different representative scenarii.
We finally lay out a series of future developments that are needed today to
better understand and constrain these fascinating interactions.Comment: 23 pages, 10 figures, accepted as a chapter in the Handbook of
Exoplanet
Signatures of Star-planet interactions
Planets interact with their host stars through gravity, radiation and
magnetic fields, and for those giant planets that orbit their stars within
10 stellar radii (0.1 AU for a sun-like star), star-planet
interactions (SPI) are observable with a wide variety of photometric,
spectroscopic and spectropolarimetric studies. At such close distances, the
planet orbits within the sub-alfv\'enic radius of the star in which the
transfer of energy and angular momentum between the two bodies is particularly
efficient. The magnetic interactions appear as enhanced stellar activity
modulated by the planet as it orbits the star rather than only by stellar
rotation. These SPI effects are informative for the study of the internal
dynamics and atmospheric evolution of exoplanets. The nature of magnetic SPI is
modeled to be strongly affected by both the stellar and planetary magnetic
fields, possibly influencing the magnetic activity of both, as well as
affecting the irradiation and even the migration of the planet and rotational
evolution of the star. As phase-resolved observational techniques are applied
to a large statistical sample of hot Jupiter systems, extensions to other
tightly orbiting stellar systems, such as smaller planets close to M dwarfs
become possible. In these systems, star-planet separations of tens of stellar
radii begin to coincide with the radiative habitable zone where planetary
magnetic fields are likely a necessary condition for surface habitability.Comment: Accepted for publication in the handbook of exoplanet
Mental health first aid training in a workplace setting: A randomized controlled trial [ISRCTN13249129]
BACKGROUND: The Mental Health First Aid training course was favorably evaluated in an uncontrolled trial in 2002 showing improvements in participants' mental health literacy, including knowledge, stigmatizing attitudes, confidence and help provided to others. This article reports the first randomized controlled trial of this course. METHODS: Data are reported on 301 participants randomized to either participate immediately in a course or to be wait-listed for 5 months before undertaking the training. The participants were employees in two large government departments in Canberra, Australia, where the courses were conducted during participants' work time. Data were analyzed according to an intention-to-treat approach. RESULTS: The trial found a number of benefits from this training course, including greater confidence in providing help to others, greater likelihood of advising people to seek professional help, improved concordance with health professionals about treatments, and decreased stigmatizing attitudes. An additional unexpected but exciting finding was an improvement in the mental health of the participants themselves. CONCLUSIONS: The Mental Health First Aid training has shown itself to be not only an effective way to improve participants' mental health literacy but also to improve their own mental health. It is a course that has high applicability across the community
Impact of Spontaneous Extracranial Bleeding Events on Health State Utility in Patients with Atrial Fibrillation: Results from the ENGAGE AF-TIMI 48 Trial.
BACKGROUND: The impact of different types of extracranial bleeding events on health-related quality of life and health-state utility among patients with atrial fibrillation is not well understood. METHODS AND RESULTS: The ENGAGE AF-TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) Trial compared edoxaban with warfarin with respect to the prevention of stroke or systemic embolism in atrial fibrillation. Data from the EuroQol-5D (EQ-5D-3L) questionnaire, prospectively collected at 3-month intervals for up to 48 months, were used to estimate the impact of different categories of bleeding events on health-state utility over 12 months following the event. Longitudinal mixed-effect models revealed that major gastrointestinal bleeds and major nongastrointestinal bleeds were associated with significant immediate decreases in utility scores (-0.029 [-0.044 to -0.014; P<0.001] and -0.029 [-0.046 to -0.012; P=0.001], respectively). These effects decreased in magnitude over time, and were no longer significant for major nongastrointestinal bleeds at 9 months, but remained borderline significant for major gastrointestinal bleeds at 12 months. Clinically relevant nonmajor and minor bleeds were associated with smaller but measurable immediate impacts on utility (-0.010 [-0.016 to -0.005] and -0.016 [-0.024 to -0.008]; P<0.001 for both), which remained relatively constant and statistically significant over the 12 months following the bleeding event. CONCLUSIONS: All categories of bleeding events were associated with negative impacts on health-state utility in patients with atrial fibrillation. Major bleeds were associated with relatively large immediate decreases in utility scores that gradually diminished over 12 months; clinically relevant nonmajor and minor bleeds were associated with smaller immediate decreases in utility that persisted over 12 months. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00781391
A dusty pinwheel nebula around the massive star WR 104
Wolf-Rayet (WR) stars are luminous massive blue stars thought to be immediate
precursors to the supernova terminating their brief lives. The existence of
dust shells around such stars has been enigmatic since their discovery some 30
years ago; the intense radiation field from the star should be inimical to dust
survival. Although dust-creation models, including those involving interacting
stellar winds from a companion star, have been put forward, high-resolution
observations are required to understand this phenomena. Here we present
resolved images of the dust outflow around Wolf-Rayet WR 104, obtained with
novel imaging techniques, revealing detail on scales corresponding to about 40
AU at the star. Our maps show that the dust forms a spatially confined stream
following precisely a linear (or Archimedian) spiral trajectory. Images taken
at two separate epochs show a clear rotation with a period of 220 +/- 30 days.
Taken together, these findings prove that a binary star is responsible for the
creation of the circumstellar dust, while the spiral plume makes WR 104 the
prototype of a new class of circumstellar nebulae unique to interacting wind
systems.Comment: 7 pages, 2 figures, Appearing in Nature (1999 April 08
Relationship between quality of life and psychopathological profile: data from an observational study in children with ADHD
Although ADHD significantly affects the quality of life (QoL) of patients and their families, QoL in children with ADHD has rarely been investigated in association with psychopathological profile, and the relationship remains unclear. The open-label OBSEER study evaluated the effectiveness and tolerability of Equasym XL®, a modified-release methylphenidate, in routine care of children and adolescents (aged 6–17 years) with ADHD. At baseline, questionnaires assessing psychopathological profile (Strengths and Difficulties Questionnaire, SDQ; parental ratings) and QoL (KINDL; parent, child or adolescent versions) were completed; QoL was reassessed at final visit. We analysed the relationship between psychopathology and parent/patient-rated QoL in ADHD at baseline. Data from 721 consecutively referred children and adolescents were analysed. QoL was similarly low from parent and self-ratings and independent of severity on the SDQ subscale hyperactivity/inattention. Self-ratings indicated that additional conduct disorder was associated with further reduction in QoL. Similarly, children with high scores from parent and adolescent ratings on the SDQ subscale conduct problems had reduced QoL on some KINDL subscales. Adolescents with ADHD not receiving medication at baseline reported lower QoL than those already on medication. Results show that children and adolescents with ADHD have low QoL, independent of core symptom severity. Additional conduct problems may further impact QoL negatively, while ADHD medication use may show a trend towards improved QoL. Not all psychopathological problems associated with ADHD affect QoL similarly. As parents appear to have a less critical view of QoL compared with children’s self-ratings, both parent and child ratings should be included in clinical assessments
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