Evidence for enhanced chromospheric Ca II H & K emission in stars with close-in extrasolar planets

The planet-star interaction is manifested in many ways. It was found out that a close-in exoplanet causes small but measurable variability in the cores of a few lines in the spectra of several stars which corresponds to the orbital period of the exoplanet. Stars with and without exoplanets may have different properties. The main goal of our study is to search for influence which exoplanets might have on atmospheres of their host stars. Unlike the previous studies, we do not study changes in the spectrum of a host star or differences between stars with and without exoplanets. We aim to study a large number of stars with exoplanets, current level of their chromospheric activity and look for a possible correlation with the exoplanetary properties. To analyse the chromospheric activity of stars we exploit our own (2.2m ESO/MPG telescope) and publicly available archival spectra (Keck Observatory Archive), measure the equivalent widths of the cores of Ca II H and K lines and use them as a tracer of their activity. Subsequently, we search for their dependence on the orbital parameters and mass of the exoplanet. We found a statistically significant evidence that the equivalent width of the Ca II K line emission and log R'_{HK} activity parameter of the host star varies with the semi-major axis and mass of the exoplanet. Stars with T_eff <= 5500 K having exoplanets with semi-major axis a <= 0.15 AU (P_orb <= 20 days) have a broad range of Ca II K emissions and much stronger emission in general than stars at similar temperatures but with higher values of semi-major axes. Ca II K emission of cold stars (T_eff <= 5500 K) with close-in exoplanets (a <= 0.15 AU) is also more pronounced for more massive exoplanets. The overall level of the chromospheric activity of stars may be affected by their close-in exoplanets. Stars with massive close-in exoplanets may be more active.Comment: 9 pages, 8 figures, 1 tabl

Longitudinal evaluation, acceptability and long-term retention of knowledge on a horizontally integrated organic and functional systems course

Undergraduate medical education is moving from traditional disciplinary basic science courses into more integrated curricula. Integration models based on organ systems originated in the 1950s, but few longitudinal studies have evaluated their effectiveness. This article outlines the development and implementation of the Organic and Functional Systems (OFS) courses at the University of Minho in Portugal, using evidence collected over 10 years. It describes the organization of content, student academic performance and acceptability of the courses, the evaluation of preparedness for future courses and the retention of knowledge on basic sciences. Students consistently rated the OFS courses highly. Physician tutors in subsequent clinical attachments considered that students were appropriately prepared. Performance in the International Foundations of Medicine examination of a self-selected sample of students revealed similar performances in basic science items after the last OFS course and 4 years later, at the moment of graduation. In conclusion, the organizational and pedagogical approaches of the OFS courses achieve high acceptability by students and result in positive outcomes in terms of preparedness for subsequent training and long-term retention of basic science knowledge

Language Improvement One Week After Thrombolysis in Acute Stroke

OBJECTIVES: Language recovery following acute stroke is difficult to predict due to several evaluation factors and time constraints. We aimed to investigate the predictors of aphasia recovery and to identify the National Institute of Health and Stroke Scale (NIHSS) items that best reflect linguistic performance, 1 week after thrombolysis. MATERIALS AND METHODS: We retrieved data from a prospective registry of patients with aphasia secondary to left middle cerebral artery (MCA) stroke treated with intravenous thrombolysis. Complete recovery at day 7 (D7) was measured in a composite verbal score (CVS) (Σ Language+Questions+Commands NIHSS scores). Lesion size was categorized by the Alberta Stroke Program Early CT score (ASPECTS) and vascular patency by ultrasound. CVS was correlated with standardized aphasia testing if both were performed within a two-day interval. RESULTS: Of 228 patients included (age average 67.32 years, 131 men), 72% presented some language improvement that was complete in 31%. Total recovery was predicted by ASPECTS (OR=1.65; 95% CI, 1.295-2.108; P < 0.00) and baseline aphasia severity (OR=0.439; 95% CI, 0.242-0.796; P < 0.007). CVS correlated better with standardized aphasia measures (aphasia quotient, severity, comprehension) than NIHSS_Language item. CONCLUSIONS: Lesion size and initial aphasia severity are the main predictors of aphasia recovery one week after thrombolysis. A NIHSS composite verbal score seems to capture the global linguistic performance better than the language item alone.info:eu-repo/semantics/publishedVersio

Star-planet magnetic interaction and activity in late-type stars with close-in planets

Late-type stars interact with their close-in planets through their coronal magnetic fields. We introduce a theory for the interaction between the stellar and planetary fields focussing on the processes that release magnetic energy in the stellar coronae. We consider the energy dissipated by the reconnection between the stellar and planetary magnetic fields as well as that made available by the modulation of the magnetic helicity of the coronal field produced by the orbital motion of the planet. We estimate the powers released by both processes in the case of axisymmetric and non-axisymmetric, linear and non-linear force-free coronal fields finding that they scale as v_r (B_s)^(4/3) (B_p)^(2/3) (R_p)^2, where v_r is the relative velocity between the stellar and planetary fields, B_s the mean stellar surface field, B_p the planetary field at the poles, and R_p the radius of the planet. A chromospheric hot spot or a flaring activity phased to the orbital motion of the planet are found only when the stellar field is axisymmetric. In the case of a non-axisymmetric field, the time modulation of the energy release is multiperiodic and can be easily confused with the intrinsic stellar variability. We apply our theory to the systems with some reported evidence of star-planet magnetic interaction finding a dissipated power at least one order of magnitude smaller than that emitted by the chromospheric hot spots. The phase lags between the planets and the hot spots are reproduced by our models in all the cases except for upsilon And. In conclusion, the chromospheric hot spots rotating in phase with the planets cannot be explained by the energy dissipation produced by the interaction between stellar and planetary fields as considered by our models and require a different mechanism.Comment: 16 pages, 3 figures, accepted by Astronomy and Astrophysic

Using global existing fiber networks for environmental sensing

We review recent advances in distributed fiber optic sensing (DFOS) and their applications. The scattering mechanisms in glass, which are exploited for reflectometry-based DFOS, are Rayleigh, Brillouin, and Raman scatterings. These are sensitive to either strain and/or temperature, allowing optical fiber cables to monitor their ambient environment in addition to their conventional role as a medium for telecommunications. Recently, DFOS leveraged technologies developed for telecommunications, such as coherent detection, digital signal processing, coding, and spatial/frequency diversity, to achieve improved performance in terms of measurand resolution, reach, spatial resolution, and bandwidth. We review the theory and architecture of commonly used DFOS methods. We provide recent experimental and field trial results where DFOS was used in wide-ranging applications, such as geohazard monitoring, seismic monitoring, traffic monitoring, and infrastructure health monitoring. Events of interest often have unique signatures either in the spatial, temporal, frequency, or wavenumber domains. Based on the temperature and strain raw data obtained from DFOS, downstream postprocessing allows the detection, classification, and localization of events. Combining DFOS with machine learning methods, it is possible to realize complete sensor systems that are compact, low cost, and can operate in harsh environments and difficult-to-access locations, facilitating increased public safety and smarter cities

Behavioral response to headache: a comparison between migraine and tension-type headache.

OBJECTIVE: To compare patients with migraine and tension-type headache in their behavior during the attacks and the maneuvers used to relieve the pain. BACKGROUND: Patients with headache often perform nonpharmacological measures to relieve the pain, but it is not known if these behaviors vary with the diagnosis, clinical features, and pathogenesis. METHODS: One hundred consecutive patients with either migraine (n = 72 ) or tension-type headache (n = 28) were questioned (including the use of a checklist) concerning their usual behavior during the attacks and nonpharmacological maneuvers performed to relieve the pain. The results of the two types of headache were compared. RESULTS: Patients with migraine tended to perform more maneuvers than individuals with tension-type headache (mean, 6.2 versus 3). These maneuvers included pressing and applying cold stimuli to the painful site, trying to sleep, changing posture, sitting or reclining in bed (using more pillows than usual to lay down), isolating themselves, using symptomatic medication, inducing vomiting, changing diet, and becoming immobile during the attacks. The only measure predominantly reported by patients with tension-type headache was scalp massage. However, the benefit derived from these measures was not significantly different between the two groups (except for a significantly better response to isolation, local pressure, local cold stimulation, and symptomatic medication in migraineurs). CONCLUSIONS: The behavior of patients during headache attacks varies with the diagnosis. Measures that do not always result in pain relief are performed to prevent its worsening or to improve associated symptoms. These behavioral differences may be due to the different pathogenesis of the attacks or to different styles of dealing with the pain. They can also aid the differential diagnosis between headaches in doubtful cases

Finding Plastic Patches in Coastal Waters using Optical Satellite Data

Satellites collecting optical data offer a unique perspective from which to observe the problem of plastic litter in the marine environment, but few studies have successfully demonstrated their use for this purpose. For the first time, we show that patches of floating macroplastics are detectable in optical data acquired by the European Space Agency (ESA) Sentinel-2 satellites and, furthermore, are distinguishable from naturally occurring materials such as seaweed. We present case studies from four countries where suspected macroplastics were detected in Sentinel-2 Earth Observation data. Patches of materials on the ocean surface were highlighted using a novel Floating Debris Index (FDI) developed for the Sentinel-2 Multi-Spectral Instrument (MSI). In all cases, floating aggregations were detectable on sub-pixel scales, and appeared to be composed of a mix of seaweed, sea foam, and macroplastics. Building first steps toward a future monitoring system, we leveraged spectral shape to identify macroplastics, and a Naïve Bayes algorithm to classify mixed materials. Suspected plastics were successfully classified as plastics with an accuracy of 86

f(R) theories

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom