14,154 research outputs found
On the relation between the mass of Compact Massive Objects and their host galaxies
Supermassive black holes and/or very dense stellar clusters are found in the
central regions of galaxies. Nuclear star clusters are present mainly in faint
galaxies while upermassive black holes are common in galaxies with masses M. In the intermediate galactic mass range both types of
central massive objects (CMOs) are found. Here we present our collection of a
huge set of nuclear star cluster and massive black hole data that enlarges
significantly already existing data bases useful to investigate for
correlations of their absolute magnitudes, velocity dispersions and masses with
structural parameters of their host galaxies. In particular, we directed our
attention to some differences between the correlations of nuclear star clusters
and massive black holes as subsets of CMOs with hosting galaxies. In this
context, the mass-velocity dispersion relation plays a relevant role because it
seems the one that shows a clearer difference between the supermassive black
holes and nuclear star clusters. The has a slope of while has the much smaller slope of .
The slopes of the CMO mass- host galaxy B magnitude of the two types of CMOs
are indistinguishable within the errors while that of the NSC mass-host galaxy
mass relation is significantly smaller than for supermassive black holes.
Another important result is the clear depauperation of the NSC population in
bright galaxy hosts, which reflects also in a clear flattening of the NSC mass
vs host galaxy mass at high host masses.Comment: 12 pages, 22 figures, 2 tables, accepted for publication in MNRA
An Iterative Cyclic Algorithm for Designing Vaccine Distribution Networks in Low and Middle-Income Countries
The World Health Organization's Expanded Programme on Immunization (WHO-EPI)
was developed to ensure that all children have access to common childhood
vaccinations. Unfortunately, because of inefficient distribution networks and
cost constraints, millions of children in many low and middle-income countries
still go without being vaccinated. In this paper, we formulate a mathematical
programming model for the design of a typical WHO-EPI network with the goal of
minimizing costs while providing the opportunity for universal coverage. Since
it is only possible to solve small versions of the model optimally, we describe
an iterative heuristic that cycles between solving restrictions of the original
problem and show that it can find very good solutions in reasonable time for
larger problems that are not directly solvable.Comment: International Joint Conference on Industrial Engineering and
Operations Management- ABEPRO-ADINGOR-IISE-AIM-ASEM (IJCIEOM 2019). Novi Sad,
Serbia, July 15-17t
Intervenció arqueològica a l'edifici medieval de Torreferrussa, la domus fortificada de Canalies (s. XII-XIII)
- …