44 research outputs found
UBVI CCD Photometry of the Old Open Cluster Berkeley 17
Photometric UBVI CCD photometry is presented for NGC 188 and Berkeley 17.
Color-magnitude diagrams (CMDs) are constructed and reach well past the
main-sequence turn-off for both clusters. Cluster ages are determined by means
of isochrone fitting to the cluster CMDs. These fits are constrained to agree
with spectroscopic metallicity and reddening estimates. Cluster ages are
determined to be 7.0+/-0.5 Gyr for NGC 188, and 10.0+/- 1.0 Gyr for Berkeley
17, where the errors refer to uncertainties in the relative age determinations.
These ages are compared to the ages of relatively metal-rich inner halo/thick
disk globular clusters and other old open clusters. Berkeley 17 and NGC 6791
are the oldest open clusters with an age of 10 Gyr. They are 2 Gyr younger than
the thick disk globular clusters. These results confirm the status of Berkeley
17 as one of the oldest known open cluster in the Milky Way, and its age
provides a lower limit to the age of the Galactic disk.Comment: to appear in AJ; 28 pages, 9 figure
Chemical Homogeneity in Collinder 261 and Implications for Chemical Tagging
This paper presents abundances for 12 red giants of the old open cluster
Collinder 261 based on spectra from VLT/UVES. Abundances were derived for Na,
Mg, Si, Ca, Mn, Fe, Ni, Zr and Ba. We find the cluster has a solar-level
metallicity of [Fe/H] = -0.03 dex. However some alpha elements were found to be
enhanced. The star-to-star scatter was consistent with the expected measurement
uncertainty for all elements. The observed rms scatter is as follows: Na =
0.07, Mg = 0.05, Si = 0.06, Ca = 0.05, Mn = 0.03, Fe = 0.02, Ni = 0.04, Zr =
0.12, and Ba = 0.03 dex. The intrinsic scatter was estimated to be less than
0.05 dex. Such high levels of homogeneity indicate that chemical information
remains preserved in this old open cluster.
We use the chemical homogeneity we have now established in Cr 261, Hyades and
the HR1614 moving group to examine the uniqueness of the individual cluster
abundance patterns, ie. chemical signatures. We demonstrate that the three
studied clusters have unique chemical signatures, and discuss how other such
signatures may be searched for in the future. Our findings support the prospect
of chemically tagging disk stars to common formation sites in order to unravel
the dissipative history of the Galactic disk.Comment: 26 pages, 15 figures, accepted by AJ. Uses emulateapj.cl
The Self-Regulation of Learning \u2013 Self-Report Scale for Sport Practice: Validation of an Italian Version for Football
Self-regulation of learning (SRL) is a key psychological factor that supports young athletes aiming to reach the elite level by promoting their involvement in deliberate practice. We contributed to the validation of the Italian version of the Bartulovic et al. (2017) Self-Regulation of Learning \u2013 Self-Report Scale for Sport Practice by testing its factorial structure, reliability, and measurement invariance among elite and non-elite football players, involving 415 male professional, semi-professional, and amateur youth academy players (Mage = 16.2, SD = 1.51). The original six-factor structure (planning, reflection, effort, self-efficacy, self-monitoring, and evaluation) did not fit the data well and a five-factor solution (where self-monitoring and evaluation items load on the same factor, named \u201cself-supervision\u201d) was a better fit. This five-factor solution was measurement invariant across groups of elite and non-elite athletes. We found that elite athletes scored significantly higher than non-elite ones in each SRL subprocess. Implications for future validation studies and for the use of this tool are discussed
Evaluation of a large set of patients with Autoimmune Polyglandular Syndrome from a single reference centre in context of different classifications
Purpose: To characterize patients with APS and to propose a new approach for their follow-up. Query ID="Q1" Text="Please check the given names and familynames." Methods: Monocentric observational retrospective study enrolling patients referred to the Outpatients clinic of the Units of Endocrinology, Diabetology, Gastroenterology, Rheumatology and Clinical Immunology of our Hospital for Autoimmune diseases. Results: Among 9852 patients, 1174 (11.9%) [869 (73.9%) female] were diagnosed with APS. In 254 subjects, the diagnosis was made at first clinical evaluation (Group 1), all the other patients were diagnosed with a mean latency of 11.3 ± 10.6 years (Group 2). Group 1 and 2 were comparable for age at diagnosis (35.7 ± 16.3 vs. 40.4 ± 16.6 yrs, p =.698), but different in male/female ratio (81/173 vs 226/696, p =.019). In Group 2, 50% of patients developed the syndrome within 8 years of follow-up. A significant difference was found after subdividing the first clinical manifestation into the different outpatient clinic to which they referred (8.7 ± 8.0 vs. 13.4 ± 11.6 vs. 19.8 ± 8.7 vs. 7.4 ± 8.1 for endocrine, diabetic, rheumatologic, and gastroenterological diseases, respectively, p <.001). Conclusions: We described a large series of patients affected by APS according to splitters and lumpers. We propose a flowchart tailored for each specialist outpatient clinic taking care of the patients. Finally, we recommend regular reproductive system assessment due to the non-negligible risk of developing premature ovarian failure
Subclinical giant cell arteritis in new onset polymyalgia rheumatica:A systematic review and meta-analysis of individual patient data
Objectives: To determine the prevalence and predictors of subclinical giant cell arteritis (GCA) in patients with newly diagnosed polymyalgia rheumatica (PMR). Methods: PubMed, Embase, and Web of Science Core Collection were systematically searched (date of last search July 14, 2021) for any published information on any consecutively recruited cohort reporting the prevalence of GCA in steroid-naïve patients with PMR without cranial or ischemic symptoms. We combined prevalences across populations in a random-effect meta-analysis. Potential predictors of subclinical GCA were identified by mixed-effect logistic regression using individual patient data (IPD) from cohorts screened with PET/(CT). Results: We included 13 cohorts with 566 patients from studies published between 1965 to 2020. Subclinical GCA was diagnosed by temporal artery biopsy in three studies, ultrasound in three studies, and PET/(CT) in seven studies. The pooled prevalence of subclinical GCA across all studies was 23% (95% CI 14%-36%, I2=84%) for any screening method and 29% in the studies using PET/(CT) (95% CI 13%-53%, I2=85%) (n=266 patients). For seven cohorts we obtained IPD for 243 patients screened with PET/(CT). Inflammatory back pain (OR 2.73, 1.32-5.64), absence of lower limb pain (OR 2.35, 1.05-5.26), female sex (OR 2.31, 1.17-4.58), temperature >37° (OR 1.83, 0.90-3.71), weight loss (OR 1.83, 0.96-3.51), thrombocyte count (OR 1.51, 1.05-2.18), and haemoglobin level (OR 0.80, 0.64-1.00) were most strongly associated with subclinical GCA in the univariable analysis but not C-reactive protein (OR 1.00, 1.00-1.01) or erythrocyte sedimentation rate (OR 1.01, 1.00-1.02). A prediction model calculated from these variables had an area under the curve of 0.66 (95% CI 0.55-0.75). Conclusion: More than a quarter of patients with PMR may have subclinical GCA. The prediction model from the most extensive IPD set has only modest diagnostic accuracy. Hence, a paradigm shift in the assessment of PMR patients in favour of implementing imaging studies should be discussed