54,879 research outputs found
Mass distribution and structural parameters of Small Magellanic Cloud star clusters
In this work we estimate, for the first time, the total masses and mass
function slopes of a sample of 29 young and intermediate-age SMC clusters from
CCD Washington photometry. We also derive age, interstellar reddening and
structural parameters for most of the studied clusters by employing a
statistical method to remove the unavoidable field star contamination. Only
these 29 clusters out of 68 originally analysed cluster candidates present
stellar overdensities and coherent distribution in their colour-magnitude
diagrams compatible with the existence of a genuine star cluster. We employed
simple stellar population models to derive general equations for estimating the
cluster mass based only on its age and integrated light in the B, V, I, C and
T1 filter. These equations were tested against mass values computed from
luminosity functions, showing an excellent agreement. The sample contains
clusters with ages between 60 Myr and 3 Gyr and masses between 300 and 3000 Mo
distributed between ~0.5 deg. and ~2 deg. from the SMC optical centre. We
determined mass function slopes for 24 clusters, of which 19 have slopes
compatible with that of Kroupa IMF (2.3 +/- 0.7), considering the
uncertainties. The remaining clusters - H86-188, H86-190, K47, K63 and NGC242 -
showed flatter MFs. Additionally, only clusters with masses lower than ~1000 Mo
and flatter MF were found within ~0.6 deg. from the SMC rotational centre.Comment: 12 pages, 19 figures. Includes another 29 full-page figures of
supplementary material. Accepted for publication in the MNRA
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A design framework for enabling sustainability in the clothing sector
This article discusses general strategies to enable environmental sustainability within the clothing sector, providing a framework for decision makers involved in the development of programs and policies for this sector. It initially revises the environmental impact of the clothing system and determines its key environmental sustainability priorities. The framework involves five evolutionary strategies for enabling sustainable consumption and production: 1) environmental improvement of flows throughout the supply chain; 2) environmental redesign of existing clothes; 3) design of new clothes intrinsically more sustainable; 4) design of cloth-service systems and 5) promoting life styles towards sufficient consumption. The practical implications of each strategy is analysed based on correspondent ex-post-facto case studies identified in Brazil, using data collected through literature review and desktop research
On FRW Model in Conformal Teleparallel Gravity
In this paper we use the conformal teleparallel gravity to study an isotropic
and homogeneous Universe which is settled by the FRW metric. We solve the field
equations and we obtain the behavior of some cosmological parameters such as
scale factor, deceleration parameter and the energy density of the perfect
fluid which is the matter field of our model. The field equations, that we
called modified Friedmann equations, allow us to define a dark fluid, with dark
energy density and dark pressure, responsible for the acceleration in the
Universe.Comment: Accepted in EPJ
On Lorentz violation in scattering at finite temperature
Small violation of Lorentz and CPT symmetries may emerge in models unifying
gravity with other forces of nature. An extension of the standard model with
all possible terms that violate Lorentz and CPT symmetries are included. Here a
CPT-even non-minimal coupling term is added to the covariant derivative. This
leads to a new interaction term that breaks the Lorentz symmetry. Our main
objective is to calculate the cross section for the
scattering in order to
investigate any violation of Lorentz and/or CPT symmetry at finite temperature.
Thermo Field Dynamics formalism is used to consider finite temperature effects.Comment: 12 pages, 1 figure, accepted for publication in PL
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