1,329 research outputs found
Non-formal environmental education in a vulnerable region: Insights from a 20-year long engagement in Petrópolis, Rio de Janeiro, Brazil
Environmental education is essential in the diffusion of the ethics, values, and skills that are critical to sustainable transformations. This paper presents the experience of non-formal environmental education approaches held in schools in the Petrópolis region of Rio de Janeiro, Brazil between 1997–2016. This paper adds to the literature on the relevant approaches and effectives of non-formal environmental education, especially in the vulnerable areas of low and middle-income regions that face critical environmental challenges. Specifically, to set up the context, this paper intends to firstly convey the commonly identified environmental sustainability challenges that the communities of the Petrópolis region are facing. Secondly, this report aims to convey key insights on how non-formal environmental education practices can strengthen gardening skills, environmental ethics, and sustainable food practices. These approaches have the potential to enhance the capacity of students toward sustainable transformations through encouraging them to be engaged with local social-environmental challenges. This paper adds new insights to the growing literature on non-formal environmental education, and it is hoped to inspire new educational approaches among sustainability educators
The distribution of old stars around the Milky Way's central black hole I: Star counts
(abridged) In this paper we revisit the problem of inferring the innermost
structure of the Milky Way's nuclear star cluster via star counts, to clarify
whether it displays a core or a cusp around the central black hole. Through
image stacking and improved PSF fitting we push the completeness limit about
one magnitude deeper than in previous, comparable work. Contrary to previous
work, we analyse the stellar density in well-defined magnitude ranges in order
to be able to constrain stellar masses and ages. The RC and brighter giant
stars display a core-like surface density profile within a projected radius
R<0.3 pc of the central black hole, in agreement with previous studies, but
show a cusp-like surface density distribution at larger R. The surface density
of the fainter stars can be described well by a single power-law at R<2 pc. The
cusp-like profile of the faint stars persists even if we take into account the
possible contamination of stars in this brightness range by young pre-main
sequence stars. The data are inconsistent with a core-profile for the faint
stars.Finally, we show that a 3D Nuker law provides a very good description of
the cluster structure. We conclude that the observed stellar density at the
Galactic Centre, as it can be inferred with current instruments, is consistent
with the existence of a stellar cusp around the Milky Way's central black hole,
Sgr A*. This cusp is well developed inside the influence radius of about 3 pc
of Sgr A* and can be described by a single three-dimensional power-law with an
exponent gamma=1.23+-0.05. The apparent lack of RC stars and brighter giants at
projected distances of R < 0.3 pc (R<8") of the massive black hole may indicate
that some mechanism has altered their distribution or intrinsic luminosity.Comment: Accepted for publication A&
The distribution of stars around the Milky Way's central black hole II: Diffuse light from sub-giants and dwarfs
This is the second of three papers that search for the predicted stellar cusp
around the Milky Way's central black hole, Sagittarius A*, with new data and
methods. We aim to infer the distribution of the faintest stellar population
currently accessible through observations around Sagittarius A*. We use
adaptive optics assisted high angular resolution images obtained with the NACO
instrument at the ESO VLT. Through optimised PSF fitting we remove the light
from all detected stars above a given magnitude limit. Subsequently we analyse
the remaining, diffuse light density. The analysed diffuse light arises from
sub-giant and main-sequence stars with KS ~ 19 - 20 with masses of 1 - 2 Msol .
These stars can be old enough to be dynamically relaxed. The observed power-law
profile and its slope are consistent with the existence of a relaxed stellar
cusp around the Milky Way's central black hole. We find that a Nuker law
provides an adequate description of the nuclear cluster's intrinsic shape
(assuming spherical symmetry). The 3D power-law slope near Sgr A* is \gamma =
1.23 +- 0.05. At a distance of 0.01 pc from the black hole, we estimate a
stellar mass density of 2.3 +- 0.3 x 10^7 Msol pc^-3 and a total enclosed
stellar mass of 180 +- 20 Msol. These estimates assume a constant mass-to-light
ratio and do not take stellar remnants into account. The fact that no cusp is
observed for bright (Ks 16) giant stars at projected distances of roughly
0.1-0.3 pc implies that some mechanism has altered their appearance or
distribution.Comment: Accepted for publication A&
Folding and Unfolding in the Blue Copper Protein Rusticyanin: Role of the Oxidation State
The unfolding process of the blue copper protein rusticyanin has been studied from the structural and the thermodynamic points of view at two pH values (pH 2.5 and 7.0). When Rc unfolds, copper ion remains bound to the polypeptide chain. Nuclear magnetic resonance data suggest that three of the copper ligands in the folded state are bound to the metal ion in the unfolded form, while the other native ligand is detached. These structural changes are reflected in the redox potentials of the protein in both folded and unfolded forms. The affinities of the copper ion in both redox states have been also determined at the two specified pH values. The results indicate that the presence of two histidine ligands in the folded protein can compensate the change in the net charge that the copper ion receives from their ligands, while, in the unfolded protein, charges of aminoacids are completely transferred to the copper ion, altering decisively the relative stability of its two-redox states
First results from a large-scale proper motion study of the Galactic Centre
Proper motion studies of stars in the centre of the Milky Way have been
typically limited to the Arches and Quintuplet clusters and to the central
parsec. Here, we present the first results of a large-scale proper motion study
of stars within several tens of parsecs of Sagittarius A* based on our
angular resolution GALACTICNUCLEUS survey (epoch 2015) combined with NICMOS/HST
data from the Paschen- survey (epoch 2008). This study will be the
first extensive proper motion study of the central of the
Galaxy, which is not covered adequately by any of the existing astronomical
surveys such as Gaia because of its extreme interstellar extinction ( mag). Proper motions can help us to disentangle the different
stellar populations along the line-of-sight and interpret their properties in
combination with multi-wavelength photometry from GALACTICNUCLEUS and other
sources. It also allows us to infer the dynamics and interrelationship between
the different stellar components of the Galactic Centre (GC). In particular, we
use proper motions to detect co-moving groups of stars which can trace low mass
or partially dissolved young clusters in the GC that can hardly be discovered
by any other means. Our pilot study in this work is on a field in the nuclear
bulge associated by HII regions that show the presence of young stars. We
detect the first group of co-moving stars coincident with an HII region. Using
colour-magnitude diagrams, we infer that the co-moving stars are consistent
with being the post-main sequence stars with ages of few Myrs. Simulations show
that this group of stars is a real group that can indicate the existence of a
dissolving or low to intermediate mass young cluster. A census of these
undiscovered clusters will ultimately help us to constrain star formation at
the GC in the past few ten Myrs.Comment: Accepted for publication in A&A. 13 pages, 17 figure
Study of hard double-parton scattering in four-jet events in pp collisions at √s = 7 TeV with the ATLAS experiment
Journal of High Energy Physics 2016.11 (2016): 110 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)Artículo escrito por muchos autores, sólo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración y los autores que firman como pertenecientes a la UAMInclusive four-jet events produced in proton-proton collisions at a centre-ofmass
energy of √
s = 7 TeV are analysed for the presence of hard double-parton scattering
using data corresponding to an integrated luminosity of 37.3 pb−1
, collected with the
ATLAS detector at the LHC. The contribution of hard double-parton scattering to the
production of four-jet events is extracted using an artificial neural network, assuming that
hard double-parton scattering can be approximated by an uncorrelated overlaying of dijet
events. For events containing at least four jets with transverse momentum pT ≥ 20 GeV and
pseudorapidity |η| ≤ 4.4, and at least one having pT ≥ 42.5 GeV, the contribution of hard
double-parton scattering is estimated to be fDPS = 0.092 +0.005
−0.011 (stat.)
+0.033
−0.037 (syst.). After
combining this measurement with those of the inclusive dijet and four-jet cross-sections in
the appropriate phase space regions, the effective cross-section, σeff, was determined to be
σeff = 14.9
+1.2
−1.0
(stat.)
+5.1
−3.8
(syst.) mb. This result is consistent within the quoted uncertainties
with previous measurements of σeff, performed at centre-of-mass energies between
63 GeV and 8 TeV using various final states, and it corresponds to 21+7
−6% of the total inelastic
cross-section measured at √
s = 7 TeV. The distributions of the observables sensitive
to the contribution of hard double-parton scattering, corrected for detector effects, are also
providedWe acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia;
BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska- Curie Actions, European Union; Investissements d’Avenir Labex and Idex, ANR, Région Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valenciana, Spain; the Royal Society and Leverhulme Trust, United Kingdo
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