159 research outputs found
THE POTENTIALS OF A TRANSIENT TRANSNATIONAL COMMUNITY FOR TEACHER EDUCATORS’ PROFESSIONAL LEARNING AND DEVELOPMENT
Although there has been a rising interest in the profession of teacher educators, there is still a lack of research looking at the professional learning and development of teacher educators. Taking a European perspective, we intend to contribute to the field of teacher education. At the outset we outline current literature and research findings, indicating various challenges that teacher education professionals face in today’s society, which are prominent in many contexts of language teacher education. Choosing to study a transient transnational community of 11 teacher educators as an autoethnographic case, we draw on qualitative data collected in the context of the ERASMUS+ project proPIC and use Interpretative Phenomenological Analysis (IPA) to approach our data. In this article, we provide an overview of factors that teacher educators describe as beneficial and restraining when engaging in a transnational transient community. Based on our findings, we argue that through a systematically planned implementation and critical evaluation of transient transnational communities in language teacher education, professional learning can be fostered. Article visualizations
On the Transit Potential of the Planet Orbiting iota Draconis
Most of the known transiting exoplanets are in short-period orbits, largely
due to the bias inherent in detecting planets through the transit technique.
However, the eccentricity distribution of the known radial velocity planets
results in many of those planets having a non-negligible transit probability.
One such case is the massive planet orbiting the giant star iota Draconis, a
situation where both the orientation of the planet's eccentric orbit and the
size of the host star inflate the transit probability to a much higher value
than for a typical hot Jupiter. Here we present a revised fit of the radial
velocity data with new measurements and a photometric analysis of the stellar
variability. We provide a revised transit probability, an improved transit
ephemeris, and discuss the prospects for observing a transit of this planet
from both the ground and space.Comment: 6 pages, 7 figures, accepted for publication in ApJ. Radial
velocities will be made available in the on-line version and through the NASA
Star and Exoplanet Database (NStED). Minor corrections from ApJ proof have
been applie
Identification of Cardiomyopathy-Associated Circulating miRNA Biomarkers in Muscular Dystrophy Female Carriers Using a Complementary Cardiac Imaging and Plasma Profiling Approach
Background: Different from males with Duchenne/Becker muscular dystrophy (DMD/BMD) in whom overt myopathy is the rule, muscular dystrophy (MD) female carriers are mostly free of skeletal muscle symptoms. However, similar to MD males, these females are also prone to cardiomyopathy. Since circulating microRNAs (miRNAs) have been proposed as diagnostic biomarkers for various cardiovascular diseases, the aim of the current study was to identify specific circulating miRNAs in the plasma of female DMD/BMD carriers that may allow an early and accurate diagnosis of cardiac involvement in these cases.Methods: Twenty-nine female MD carriers and 24 age-matched healthy female controls were prospectively enrolled. All MD carriers and controls underwent comprehensive cardiovascular magnetic resonance (CMR) studies as well as venous blood sampling on the same day.Results: An impaired left ventricular (LV) systolic function was detected in 4 (14%) MD carriers while late gadolinium enhancement (LGE) indicative of myocardial fibrosis was present in 13 female patients (45%)—with an exclusively non-ischemic pattern. Among the circulating miRNAs examined, six were significantly up-regulated in MD carriers compared to female controls: miR-206 (103-fold increase, p < 0.0001), miR-222 (41-fold, p < 0.0001), miR-26a (fourfold, p = 0.029), miR-342 (27-fold, p < 0.0001), miR-378a-3p (minimum 3,600-fold; almost undetectable in controls, p = 0.013), miR-378a-5p (64-fold, p < 0.0001); only two miRNAs were substantially down-regulated in MD carriers: miR-144 (p < 0.0001) and miR-29a (p = 0.002) (both undetectable in carriers). A significant down-regulation of the miR-29c (<0.001-fold, p = 0.006) was observed in MD carriers with abnormal CMR findings (comprising functional and/or structural abnormalities) compared to those with normal CMR examinations. Univariable analyses regarding the presence of abnormal CMR findings resulted in four significant variables: LV end-diastolic volume index (EDVi), LV end-systolic volume index (ESVi), an elevated plasma creatine kinase (CK), and decreased serum miR-29c levels. In subsequent multivariable analysis, the only independent predictor for an abnormal CMR among MD carriers was circulating miR-29c (OR 0.99, 95% CI 0.98–0.99, p = 0.037). Moreover, an elevated CK and/or a downregulated miR-29c level (<0.05 × 10-3) resulted in an improved AUC value of 0.79 (0.62–0.97, p = 0.007) (79, 80 and 80%, sensitivity, specificity and overall accuracy) for the CMR-based diagnosis of cardiomyopathy in MD carriers when compared to using the two parameters individually.Conclusion: In female MD carriers, down-regulation of circulating miR-29c relates to the presence of functional and/or structural cardiac abnormalities (as detected by CMR) and appears to be a promising novel biomarker—in addition to conventional CK plasma levels—for an early diagnosis of cardiomyopathy
Retired A Stars and Their Companions VI. A Pair of Interacting Exoplanet Pairs Around the Subgiants 24 Sextanis and HD200964
We report radial velocity measurements of the G-type subgiants 24 Sextanis
(=HD90043) and HD200964. Both are massive, evolved stars that exhibit periodic
variations due to the presence of a pair of Jovian planets. Photometric
monitoring with the T12 0.80m APT at Fairborn Observatory demonstrates both
stars to be constant in brightness to <= 0.002 mag, thus strengthening the
planetary interpretation of the radial velocity variations. 24 Sex b,c have
orbital periods of 453.8 days and 883~days, corresponding to semimajor axes
1.333 AU and 2.08 AU, and minimum masses (Msini) 1.99 Mjup and 0.86 Mjup,
assuming a stellar mass 1.54 Msun. HD200964 b,c have orbital periods of 613.8
days and 825 days, corresponding to semimajor axes 1.601 AU and 1.95 AU, and
minimum masses 1.85 Mjup and 0.90 Mjup, assuming M* = 1.44 Msun. We also carry
out dynamical simulations to properly account for gravitational interactions
between the planets. Most, if not all, of the dynamically stable solutions
include crossing orbits, suggesting that each system is locked in a mean motion
resonance that prevents close encounters and provides long-term stability. The
planets in the 24 Sex system likely have a period ratio near 2:1, while the
HD200964 system is even more tightly packed with a period ratio close to 4:3.
However, we caution that further radial velocity observations and more detailed
dynamical modelling will be required to provide definitive and unique orbital
solutions for both cases, and to determine whether the two systems are truly
resonant.Comment: AJ accepte
Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars
We present an analysis of ~5 years of Lick Observatory radial velocity
measurements targeting a uniform sample of 31 intermediate-mass subgiants (1.5
< M*/Msun < 2.0) with the goal of measuring the occurrence rate of Jovian
planets around (evolved) A-type stars and comparing the distributions of their
orbital and physical characteristics to those of planets around Sun-like stars.
We provide updated orbital solutions incorporating new radial velocity
measurements for five known planet-hosting stars in our sample; uncertainties
in the fitted parameters are assessed using a Markov Chain Monte Carlo method.
The frequency of Jovian planets interior to 3 AU is 26 (+9,-8)%, which is
significantly higher than the ~5-10% frequency observed around solar-mass
stars. The median detection threshold for our sample includes minimum masses
down to {0.2, 0.3, 0.5, 0.6, 1.3} MJup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To
compare the properties of planets around intermediate-mass stars to those
around solar-mass stars we synthesize a population of planets based on the
parametric relationship dN ~ M^{alpha}P^{beta} dlnM dlnP, the observed planet
frequency, and the detection limits we derived. We find that the values of
alpha and beta for planets around solar-type stars from Cumming et al. fail to
reproduce the observed properties of planets in our sample at the 4 sigma
level, even when accounting for the different planet occurrence rates. Thus,
the properties of planets around A stars are markedly different than those
around Sun-like stars, suggesting that only a small (~ 50%) increase in stellar
mass has a large influence on the formation and orbital evolution of planets.Comment: Accepted by the Astrophysical Journal; 15 pages, 15 figure
The obesity epidemic in 32,936 youth with type 1 diabetes (T1D) in the German/Austrian DPV and US T1D Exchange (T1DX) registries
Objective
To examine the current extent of the obesity problem in 2 large pediatric clinical registries in the US and Europe and to examine the hypotheses that increased body mass index (BMI) z-scores (BMIz) are associated with greater hemoglobin A1c (HbA1c) and increased frequency of severe hypoglycemia in youth with type 1 diabetes (T1D).
Study design
International (World Health Organization) and national (Centers for Disease Control and Prevention/German Health Interview and Examination Survey for Children and Adolescents) BMI references were used to calculate BMIz in participants (age 2-<18 years and ≥1 year duration of T1D) enrolled in the T1D Exchange (n = 11 435) and the Diabetes Prospective Follow-up (n = 21 501). Associations between BMIz and HbA1c and severe hypoglycemia were assessed.
Results
Participants in both registries had median BMI values that were greater than international and their respective national reference values. BMIz was significantly greater in the T1D Exchange vs the Diabetes Prospective Follow-up (P < .001). After stratification by age-group, no differences in BMI between registries existed for children 2-5 years, but differences were confirmed for 6- to 9-, 10- to 13-, and 14- to 17-year age groups (all P < .001). Greater BMIz were significantly related to greater HbA1c levels and more frequent occurrence of severe hypoglycemia across the registries, although these associations may not be clinically relevant.
Conclusions
Excessive weight is a common problem in children with T1D in Germany and Austria and, especially, in the US. Our data suggest that obesity contributes to the challenges in achieving optimal glycemic control in children and adolescents with T1D
- …