scholarly journals Different sodium enhancements among multiple populations of Milky Way globular clusters

2020 ◽  
Vol 643 ◽  
pp. A77
Author(s):  
Andrés E. Piatti
Keyword(s):  
Galaxy Formation ◽  
Globular Clusters ◽  
First Generation ◽  
Second Generation ◽  
Milky Way ◽  
Recent Literature ◽  
Orbital Parameters ◽  
The Difference ◽  
First And Second Generation

We searched for clues to understand the different Na abundances measured in first and second generation stars of ancient Milky Way globular clusters. For that purpose, from the recent literature, we gathered the aforementioned Na abundances, orbital parameters, and structural and internal dynamical properties and ages in a homogeneous scale of 28 globular clusters. We found that the intra-cluster Na enrichment, which is measured by the difference of Na abundances between first and second generation stars, exhibits a trend as a function of the Na abundances of first generation stars, in the sense that the more Na-poor the first generation stars are, the larger the Na enrichment is. By using the inclinations of the globular clusters’ orbits, the analyzed Na enrichments also hinted at a boundary at ∼0.3 dex to differentiate globular clusters with an accreted or in situ origin, the accreted globular clusters having larger Na enrichments. Because relatively larger intra-cluster Na enhancements are seen in accreted globular clusters and small Na enhancements are observed in globular clusters formed in situ, although not exclusively, we speculate that the amplitude of the Na enrichment may be linked with the building block paradigm. Globular clusters at the time of formation of first and second generation stars would seem to keep a memory of this hierarchical galaxy formation process.

scholarly journals The orbital evolution of UFDs and GCs in an evolving Galactic potential

2020 ◽  
Vol 500 (3) ◽  
pp. 2937-2957
Author(s):  
Benjamin M Armstrong ◽  
Kenji Bekki ◽  
Aaron D Ludlow
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Orbital Evolution ◽  
Orbital Parameters ◽  
Angular Momenta ◽  
Galactic Potential ◽  
The Galaxy ◽  
Galaxy Masses ◽  
The Difference ◽  
Evolving Models

ABSTRACT We use the second Gaia data release to investigate the kinematics of 17 ultra-faint dwarf galaxies (UFDs) and 154 globular clusters (GCs) in the Milky Way, focusing on the differences between static and evolving models of the Galactic potential. An evolving potential modifies a satellite’s orbit relative to its static equivalent, though the difference is small compared to existing uncertainties on orbital parameters. We find that the UFD Boötes II is likely on its first passage around the Milky Way. Depending on the assumed mass of the Milky Way, the UFDs Triangulum II, Hydrus I, Coma Berenices, Draco II, and Ursa Major II, as well as the GC Pyxis, may also be on first infall so may be useful for constraining the mass of the Galaxy. We identify a clear kinematic distinction between metal-rich ([Fe/H] > −1.1) and metal-poor GCs ([Fe/H] ≤ −1.1). Although most metal-rich clusters occupy predominately prograde orbits, with low eccentricities (e ≈ 0.35) and similar specific angular momenta and orbital planes as the Galactic disc, seven show potentially retrograde orbits, the origin of which is unclear. Metal-poor clusters have more diverse orbits, higher eccentricities (e ≈ 0.65), and half of them have orbital planes offset from the disc by 60° to 120°—twice as many as the metal-poor GCs. The UFDs have similar θ and ϕ to the metal-poor GCs, suggesting a similar origin. We provide a catalogue of orbital parameters for UFDs and GCs for two different Galaxy masses and their observational uncertainties.

scholarly journals On the Relationship Between Subject Placement and Overt Pronouns in the Spanish of New York City Bilinguals

2018 ◽  
Vol 11 (2) ◽  
pp. 324-347
Author(s):  
Rocío Raña-Risso ◽  
Carolina Barrera-Tobón
Keyword(s):  
New York ◽  
New York City ◽  
Word Order ◽  
York City ◽  
First Generation ◽  
Second Generation ◽  
Overt Pronouns ◽  
The Difference ◽  
First And Second Generation ◽  
The Relationship

This paper reports on a variationist sociolinguistic analysis of the relationship between subject placement and overt pronoun rates in the Spanish of first- and second-generation Spanish-English bilinguals in New York City. The data used for the study come from a spoken corpus of Spanish in New York based on 140 sociolinguistic interviews. We show second-generation speakers exhibit a more rigid word order compared to their newly arrived first-generation peers, more often preferring subjects in the preverbal position, and we explain that this increase in word order rigidity among our second-generation can be attributed, in large part, to their increased use of and contact with English. We further posit that the difference in subject placement across generations can be explained by the different context of acquisition since the Spanish that these second-generation speakers are exposed to contains both a higher rate of overt pronouns and a higher rate of preverbal subjects.

scholarly journals The origin of globular cluster FSR 1758

2020 ◽  
Vol 635 ◽  
pp. A125
Author(s):  
Fu-Chi Yeh ◽  
Giovanni Carraro ◽  
Vladimir I. Korchagin ◽  
Camilla Pianta ◽  
Sergio Ortolani
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Initial Conditions ◽  
Dwarf Galaxy ◽  
Galactic Bulge ◽  
Orbital Parameters ◽  
Bulge Region ◽  
Analytical Time

Context. Globular clusters in the Milky Way are thought to have either an in situ origin, or to have been deposited in the Galaxy by past accretion events, like the spectacular Sagittarius dwarf galaxy merger. Aims. We probe the origin of the recently discovered globular cluster FSR 1758, often associated with some past merger event and which happens to be projected toward the Galactic bulge. We performed a detailed study of its Galactic orbit, and assign it to the most suitable Galactic component. Methods. We employed three different analytical time-independent potential models to calculate the orbit of the cluster by using the Gauss Radau spacings integration method. In addition, a time-dependent bar potential model is added to account for the influence of the Galactic bar. We ran a large suite of simulations via a Montecarlo method to account for the uncertainties in the initial conditions. Results. We confirm previous indications that the globular cluster FSR 1758 possesses a retrograde orbit with high eccentricity. The comparative analysis of the orbital parameters of star clusters in the Milky Way, in tandem with recent metallicity estimates, allows us to conclude that FSR 1758 is indeed a Galactic bulge intruder. The cluster can therefore be considered an old metal-poor halo globular cluster formed in situ that is passing right now in the bulge region. Its properties, however, can be roughly accounted for by also assuming that the cluster is part of some stream of extra-Galactic origin. Conclusions. We conclude that assessing the origin, either Galactic or extra-galactic, of globular clusters is surely a tantalising task. In any case, by using an Occam’s razor argument, we tend to prefer an in situ origin for FSR 1758.

scholarly journals Gaia results for star clusters and dwarf galaxies in the Milky Way

2019 ◽  
Vol 14 (S351) ◽  
pp. 472-477
Author(s):  
Davide Massari
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Dwarf Spheroidal Galaxies ◽  
Orbital Parameters ◽  
The Galaxy ◽  
Almost All

AbstractThe second data release of the Gaia mission coupled with ground-based spectroscopic observations has allowed the determination of the orbital parameters for almost all of the Galactic globular clusters, as well as for the known dwarf spheroidal galaxies orbiting the Milky Way. Moreover, it has led to the discovery of dwarf galaxies that were accreted by the Galaxy long ago and that are now completely disrupted. By exploiting their dynamics in combination with the globular clusters age-metallicity relation, we investigated the clusters-to-dwarfs connection. We found that about 60 globulars likely formed in situ, and associated those that were accreted to the dwarf galaxy progenitor they likely formed in.

scholarly journals The ages of Galactic globular clusters in the context of self-enrichment

2008 ◽  
Vol 4 (S258) ◽  
pp. 265-274 ◽  
Author(s):  
T. Decressin ◽  
H. Baumgardt ◽  
P. Kroupa ◽  
G. Meynet ◽  
C. Charbonnel
Keyword(s):  
Globular Clusters ◽  
First Generation ◽  
Second Generation ◽  
Age Determination ◽  
Dynamical Evolution ◽  
Low Velocity ◽  
Tidal Forces ◽  
History Of ◽  
First And Second Generation

AbstractA significant fraction of stars in globular clusters (about 70%-85%) exhibit peculiar chemical patterns, with strong abundance variations in light elements along with constant abundances in heavy elements. These abundance anomalies can be created in the H-burning core of a first generation of fast-rotating massive stars, and the corresponding elements are conveyed to the stellar surface thanks to rotational induced mixing. If the rotation of the stars is fast enough, this material is ejected at low velocity through a mechanical wind at the equator. It then pollutes the interstellar medium (ISM) from which a second generation of chemically anomalous stars can be formed. The proportion of anomalous stars to normal stars observed today depends on at least two quantities: (1) the number of polluter stars; (2) the dynamical history of the cluster, which may lose different proportions of first- and second-generation stars during its lifetime. Here we estimate these proportions, based on dynamical models for globular clusters. When internal dynamical evolution and dissolution due to tidal forces are accounted for, starting from an initial fraction of anomalous stars of 10% produces a present-day fraction of about 25%, still too small with respect to the observed 70-85%. In the case of gas expulsion by supernovae, a much higher fraction is expected to be produced. In this paper we also address the question of the evolution of the second-generation stars that are He-rich, and deduce consequences for the age determination of globular clusters.

scholarly journals Comparison of Clinical Characteristics of First and Second Generation Cases of COVID-19

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Chao Rui ◽  
Liyun Chen ◽  
Nengjin Gan ◽  
Huiming Chen ◽  
Fen Huang ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
First Generation ◽  
Second Generation ◽  
Reference Value ◽  
Lung Lesions ◽  
Number Of Patients ◽  
Significant Difference ◽  
The Difference ◽  
Bilateral Lung ◽  
First And Second Generation

Purpose — To explore the differences in clinical characteristics of the first and second generation cases of COVID-19. Methods — 63 patients with COVID-19 and asymptomatic infections admitted to the Third People's Hospital of Wuhu City and the Fourth People's Hospital of Ma'anshan City from January 24, 2020 to March 3, 2020 were selected as the research objects. The patients were divided into the first and second generation case groups according to the history of epidemiology, and the differences of clinical data between the two groups were compared. Results — There was no significant difference between the two groups of patients in gender, age, and number of smokers (P>0.05). In the first generation group, the number of people with underlying diseases was lower than that in the second generation group (86.80%, 92.00%), and the number of patients of severe or critical type was higher than that in the second generation group (18.40%, 0.00%). The difference was statistically significant (P<0.05). The symptoms of the two groups were compared: fever (84.20%, 64.00%), cough (78.9%, 40.00%), chest tightness (44.70%, 12.00%), nausea (2.60%, 36.00%). The difference was statistically significant (P<0.05). The distribution of lesions in the two groups was compared: bilateral lung lesions (77.80%, 66.70%), unilateral lesions (17.80%, 5.50%), and no lesions (4.40%, 27.80%). The difference was statistically significant (P<0.05). There was no statistically significant difference between the two groups in laboratory tests (P>0.05). Conclusions — Compared with the first generation cases, the second generation cases have different degrees of relief in clinical classification, lower respiratory symptoms and the number of lung lesions; the differentiation of the transmission generation has a certain reference value for the evaluation of the disease condition.

Assimilation of the Puerto Ricans on the Mainland

1968 ◽  
Vol 2 (2) ◽  
pp. 21-39
Author(s):  
John J. Macisco
Keyword(s):  
United States ◽  
First Generation ◽  
Second Generation ◽  
Puerto Ricans ◽  
The United States ◽  
Social Scientists ◽  
First Marriage ◽  
Labor Force Status ◽  
Age At First Marriage ◽  
First And Second Generation

Social scientists have repeatedly tried to specify the process whereby assimilation takes place. This article points out the value of socio-demographic analysis in the study of assimilation, by describing the characteristics of Puerto Ricans on the United States mainland. In order to assess the direction of change between the first and second generation Puerto Ricans, data for the total United States population are also presented. Most of the data are drawn from the 1960 Census. First generation Puerto Ricans are compared with the second generation along the following dimensions: age, education, labor force status, income, occupation, age at first marriage, percent outgroup marriage and fertility. The Author concludes that second generation Puerto Ricans are moving in the direction of total United States averages.

scholarly journals First-generation versus second-generation long-acting injectable antipsychotic drugs and time to relapse

2018 ◽  
Vol 8 (12) ◽  
pp. 333-336 ◽  
Author(s):  
James M. Stone ◽  
Simon Roux ◽  
David Taylor ◽  
Paul D. Morrison
Keyword(s):  
First Generation ◽  
Antipsychotic Drugs ◽  
Second Generation ◽  
Patient Acceptability ◽  
Inpatient Ward ◽  
Medication Discontinuation ◽  
Kaplan Meier ◽  
The Difference ◽  
Long Acting ◽  
Time To Relapse

Background: The development of long-acting injectable formulations (LAIs) of second-generation antipsychotic drugs (SGAs) has been suggested as having advantage over first-generation antipsychotic (FGA) LAIs. In this study, we investigated the hypothesis that there was a longer time to relapse in patients with schizophrenia started on SGA LAI versus FGA LAI. Methods: Patients with a diagnosis of schizophrenia or schizoaffective disorder who were started on an SGA LAI while on an inpatient ward were identified through searching of the anonymised historical medical records at the South London and Maudsley NHS Foundation Trust. Patients starting FGA LAIs matched for diagnosis, age and date of hospital admission were identified. Time to readmission, discontinuation of LAI or death were identified. Kaplan–Meier plots were generated for each group, and the difference between groups analysed using log-rank methods. Results: There were 157 patients identified in each group. There was no difference in time to readmission, medication discontinuation or death in patients on SGA LAI versus FGA LAI. Conclusions: We found no evidence of advantage in terms of maintaining response in SGA LAI versus FGA LAI. Prescriber choice should be guided by other factors such as side-effect profile, patient acceptability and price.

scholarly journals Why do first and second-generation young migrants volunteer? The Migrant Volunteerism Motivation Model (MVMM)

2019 ◽  
Vol 7 (2) ◽  
pp. 1089-1107 ◽  
Author(s):  
Sara Alfieri ◽  
Daniela Marzana ◽  
Sara Martinez Damia
Keyword(s):  
Transition To Adulthood ◽  
Process Model ◽  
First Generation ◽  
Second Generation ◽  
Maintenance Phase ◽  
Structured Interviews ◽  
Sub Saharan ◽  
Italian Context ◽  
First And Second Generation ◽  
Motivation Model

The following study aims at inquiring into the motivations behind young migrants’ volunteerism in civic organizations in Italy, namely in starting and maintaining their engagement (preliminary vs. maintenance phase). The term “young migrants” refers to first and second generation of migrants who deal with two challenges: the transition to adulthood and the acquisition of a cultural identity. We conducted semi-structured interviews with 37 Sub-Saharan young migrants living in Italy (18-32 years old), 19 of first generation (1G) and 18 of second generation (2G). The Omoto and Snyder’s Volunteer Process Model (VPM, 1995) was used as an underpinning theoretical framework and a guide for the interpretations of the results. The findings indicate that a) motivations included in the VPM are also found for young migrants, b) some of these motivations take particular meaning for young migrants, c) some motivations are not included in the VPM and are specific of this sample. We named these last motivations: social norms, advocacy and ethno-cultural. In addition, some considerations may be advanced regarding the generation and the phase of motivation: 1G migrants are particularly moved by the importance of integration in the Italian context and by the promotion of their ethnic group while 2G migrants reported mostly the desire to understand their roots. The values, the concern for the community and the longing to develop relationships are the motivations for which all young migrants continue to volunteer; however, 1G migrants are also sustained by advocacy and ethno-cultural motivations. Implications and future directions are discussed.

scholarly journals The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa)

2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Bambang Suwignyo ◽  
LUKMANA ARIFIN ◽  
NAFIATUL UMAMI ◽  
MUHLISIN MUHLISIN ◽  
BAMBANG SUHARTANTO
Keyword(s):  
Organic Matter ◽  
Genetic Variation ◽  
Medicago Sativa ◽  
Crude Protein ◽  
Dry Matter ◽  
First Generation ◽  
Second Generation ◽  
Seed Viability ◽  
Nutrient Content ◽  
First And Second Generation

Abstract. Suwignyo B, Arifin L, Umami N, Muhlisin, Suhartanto B. 2021. The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa). Biodiversitas 22: 3265-3270. This study aimed to compare the growth performance, nutrient content, seed viability, and genetic variation of first- and second-generation alfalfa (Medicago sativa L.). First and second-generation alfalfa seeds were obtained from the Forage and Pasture Science Laboratory, Department of Animal Nutrition and Feed Science, Faculty of Animal Science, Universitas Gadjah Mada (UGM), Yogyakarta, Indonesia. First generation alfalfa (F1) seeds were obtained from cross breeding of two different parental alfalfa varieties, namely, Canadian and local. The second-generation (F2) seeds were obtained from plants of the first-generation alfalfa (F1). A randomized design experiment was conducted using the two types of alfalfa (first- and second generation). Alfalfa from Canada as female parent was used as the baseline in the genetic masker test. Seeds were planted in a polybag, watered twice a day, and received 12 hours of daylight and 4 hours of artificial light. Plants were then harvested 8 weeks after planting by cutting the plant canopy. Genetic variation was examined using the Inter Simple Sequence Repeat (ISSR) method followed by descriptive analysis. Germination, plant height, dry matter content, organic matter, and crude protein were assessed as variables using a Student’s T-test. Our results showed that germination, plant height, leaf color, and nutrient content (dry matter, organic matter, and crude protein) of the first- and second-generation alfalfa plants were not significantly different. However, the second-generation alfalfa demonstrated better seed viability than the first generation plants, then it can be categorized as a new genotype (tropical alfalfa) based on genetic variation analysis.

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