In this study, we estimate the fraction of binaries with high mass ratios for 202 open clusters in the extended solar neighbourhood (closer than 1.5 kpc from the Sun). This is one of the largest homogeneous catalogues of multiplicity fractions in open clusters to date, including the unresolved and total (close-binary) multiplicity fractions of main-sequence systems with mass ratio greater than $ 0.6_{ -0.15}^{+0.05} $. The unresolved multiplicity fractions were estimated applying a flexible mixture model to the observed Gaia colour-magnitude diagrams of the open clusters. Then we used custom Gaia simulations to account for the resolved systems and derived the total multiplicity fractions. The studied open clusters have ages between 6.6 Myr and 3.0 Gyr and total high-mass-ratio multiplicity fractions between 6% and 80%, with a median of 18%. The multiplicity fractions increase with the mass of the primary star, as expected. The average multiplicity fraction per cluster displays an overall decreasing trend with the open cluster age up to ages about 100 Myr, above which the trend increases. Our simulations show that most of this trend is caused by complex selection effects (introduced by the mass dependence of the multiplicity fraction and the magnitude limit of our sample). Furthermore, the multiplicity fraction is not significantly correlated with the clusters’ position in the Galaxy. The spread in multiplicity fraction decreases significantly with the number of cluster members (used as a proxy for cluster mass). We also find that the multiplicity fraction decreases with metallicity, in line with recent studies using field stars.
The proper management of urban public services (UPS) ensures that a territory functions efficiently, since it guarantees optimal waste disposal, water supply, and the maintenance of communication infrastructure, among other things. In areas of high urban density located close to metropolitan cities, UPS are usually provided properly and efficiently. However, in less populated territories, lying in the periphery, significant problems and deficiencies are often encountered, being most evident in rural areas located on the administrative limits of a state or region. This paper seeks to analyze the management of UPS in the internal border area between two Spanish regions, Aragon and Catalonia. A total of 72 stakeholders (mayors and town clerks) from 49 river municipalities were involved in this study that employs a quantitative methodology (questionnaire). The perception that there are deficiencies to correct and a clear will to reach agreements and establish cooperation mechanisms is detected in many of the municipalities in the border area. A clear need to cooperate is also apparent in a series of priority UPS, including the promotion of river tourism, town access roads, urban collective passenger transport, and environmental protection.
Urban complexity can be measured by the numerical and spatial diversity of activities in a territory. Just as biodiversity can be measured in a natural ecosystem, diversity indices can be applied to urban settings. Urban diversity presents higher values in areas where there is a greater number of (economic, institutional, and social) activities with a high degree of differentiation between them. This study seeks to investigate the potential of applying an urban diversity index in a specific case study: namely, the city of Barcelona (Spain), known for the orthogonal grid plan of its Eixample district. Results show that the municipal territory of Barcelona as a whole is characterized by highly differentiated spaces according to their urban diversity values. Specifically, it is the Eixample district that presents the highest values of urban diversity, reflecting the densification of its morphology and its urban commercial policies.
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