Collinder 135 and UBC 7: A physical pair of open clusters

Context. Given the closeness of the two open clusters Collinder 135 and UBC 7 on the sky, we investigate the possibility that the two clusters are physically related. Aims. We aim to recover the present-day stellar membership in the open clusters Cr 135 and UBC 7 (300 pc from the Sun) in order to constrain their kinematic parameters, ages, and masses and to restore their primordial phase space configuration. Methods. The most reliable cluster members are selected with our traditional method modified for the use of Gaia DR2 data. Numerical simulations use the integration of cluster trajectories backwards in time with our original high-order Hermite4 code φ−GRAPE. Results. We constrain the age, spatial coordinates, velocities, radii, and masses of the clusters. We estimate the actual separation of the cluster centres equal to 24 pc. The orbital integration shows that the clusters were much closer in the past if their current line-of-sight velocities are very similar and the total mass is more than seven times larger than the mass of the most reliable members. Conclusions. We conclude that the two clusters Cr 135 and UBC 7 might very well have formed a physical pair based on the observational evidence as well as numerical simulations. The probability of a chance coincidence is only about 2%.

HUBUNGAN PEMAKAIAN ALAT DAN OBAT KONTRASEPSI SUNTIKAN DENGAN GANGGUAN MENSTRUASI DI KLINIK NIRMALA

ABSTRACTAccording to the World Health Organization (WHO) there are nearly 380 million couples running Family planning. This research is a analttic survey with cross sectional design that is to know the relation of usage of contraception tool and contraception with menstrual disorder,sampling this research using accidental sampling that is sampling method by chance coincidence. In 85 out of 85 cases of mother using 1 month injection of polimenore/spooting injection were 50 cases (100%) while mothers using 3 Months of injectable amenorrhea (65,71%) had Spotted 12 case (34,29%) ini clinic Nirmala. Result of statistical test by using chi square test got p value =0,01<0,05 and X2 = 41,77 mean there is relation of tool usage and contraceptive injection drug with menstrual disorder 95% CI level equal to 1,84-4,61 meaning mothers who used injectable contraceptive devices 1-4 times experianced a menstrual disorder at the Nirmala ClinicKeyword: Contraceptive Injection, Medication

Exploring the association of Fermi sources with Young Stellar Objects

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ~70% of the candidates should be gamma-ray sources with a confidence of ~5σ.