78 research outputs found
O diálogo entre a educação ambiental crítico-transformadora e a capoeira Angola : a percepção da experiência no centro de pesquisa e prática nº Golo capoeira Angola, no Agreste de Pernambuco.
Capoeira Angola emerges as a concrete possibility for resistance and fight against domination, which contributes to the current ecological ruin. With the objective of to comprehend the relationship between critical-transformative Environmental Education and Capoeira Angola, from the perspective of the practice of the N'Golo Capoeira Angola Research and Practice Center in Bezerros/PE; the research was conducted using a qualitative approach, with an ethnographic emphasis. Data collection took place at the N'Golo Capoeira Angola Research and Practice Center through bibliographic study, participant observation, documentary research, and interviews with key actors. Through qualitative analysis and interpretation of the data, considering the researcher's experience, it was possible to enhance the understanding of the human-nature relationship, which is increasingly profound. This includes recognizing and valuing traditional knowledge in the face of modern paradigms, as well as the ancestral heritage that, strengthened by cosmovisions, serves as a central foundation for resistance and a critical perspective aiming to transform this reality, utilizing diverse and synergistic tools. This realization led to the understanding that critical-transformative Environmental Education and Capoeira Angola, beyond their existing connections, can mutually reinforce each other when combined for their common objectives. In summary, this study has provided significant contributions to achieving the proposed objectives. However, it is important to emphasize the need for further exploration of this topic, acknowledging that learning is an ongoing process, as "Angola is far."A Capoeira Angola se apresenta como possibilidade concreta de resistência e de luta contra a dominação que contribui para a atual ruína ecossistêmica. Com o objetivo de compreender a relação entre a Educação Ambiental crítico-transformadora e a Capoeira Angola, a partir da perspectiva da prática do Centro de Pesquisa e Prática N'Golo Capoeira Angola, em Bezerros/PE; a pesquisa foi conduzida utilizando uma abordagem qualitativa, com ênfase etnográfica. Sua coleta foi realizada no Centro de Prática e Pesquisa N'Golo Capoeira Angola a partir do estudo bibliográfico, observação participante, levantamento documental e entrevistas com atores-chave. A partir da análise e interpretação qualitativa dos dados, considerando a vivência do pesquisador, foi possível ampliar a compreensão da relação homem-natureza, cuja integração é cada vez mais profunda; do reconhecimento e da valorização dos saberes tradicionais frente aos paradigmas modernos; da ancestralidade que, fortalecida pelas cosmovisões, tem sido um alicerce central na vanguarda da resistência e da perspectiva crítica de mundo que visa transformar esta realidade, utilizando-se de ferramentas plurais e sinérgicas. Essa percepção propiciou entender que a Educação Ambiental crítico-transformadora e a Capoeira Angola, para além das conexões existentes, podem se fortalecer mutuamente quando combinadas em prol de seus objetivos comuns. Em suma, este estudo proporcionou significativas contribuições para alcançar os objetivos propostos, porém, ressalta-se a necessidade de aprofundamento dessa temática, reconhecendo que o aprendizado é um processo contínuo, pois “Angola é longe”
Far infrared and Radio emission in dusty starburst galaxies
We revisit the nature of the FIR/Radio correlation by means of the most
recent models for star forming galaxies. We model the IR emission with our
population synthesis code, GRASIL (Silva et al. 1998). As for the radio
emission, we revisit the simple model of Condon & Yin (1990). We find that a
tightFIR/Radio correlation is natural when the synchrotron mechanism dominates
over the inverse Compton, and the electrons cooling time is shorter than the
fading time of the supernova rate. Observations indicate that both these
conditions are met in star forming galaxies. However since the radio non
thermal emission is delayed, deviations are expected both in the early phases
of a starburst, when the radio thermal component dominates, and in the
post-starburst phase, when the bulk of the NT component originates from less
massive stars. This delay allows the analysis of obscured starbursts with a
time resolution of a few tens of Myrs, unreachable with other star formation
indicators. We suggest to complement the analysis of the deviations from the
FIR/Radio correlation with the radio slope to obtain characteristic parameters
of the burst. The analysis of a sample of compact ULIRGs shows that they are
intense but transient starbursts, to which one should not apply usual SF
indicators devised for constant SF rates. We also discuss the possibility of
using the q- radio slope diagram to asses the presence of obscured AGN. A firm
prediction of the models is an apparent radio excess during the post-starburst
phase, which seems to be typical of a class of star forming galaxies in rich
cluster cores. We discuss how deviations from the correlation, due to the
evolutionary status of the starburst, affect the technique of photometric
redshift determination widely used for high-z sources.Comment: accepted by A&A, 16 page
Production of green surfactants: Market prospects
Science has greatly contributed to the advancement of technology and to the innovation of production processes and their applications. Cleaning products have become indispensable in today\u2019s world, as personal and environmental hygiene is important to all societies worldwide. Such products are used in the home, in most work environments and in the industrial sectors. Most of the detergents on the market are synthesised from petrochemical products. However, the interest in reducing the use of products harmful to human health and the environment has led to the search for detergents formulated with natural, biodegradable surfactant components of biological (plant or microbiological) origin or chemically synthesised from natural raw materials usually referred to as green surfactants. This review addresses the different types, properties, and uses of surfactants, with a focus on green surfactants, and describes the current scenario as well as the projections for the future market economy related to the production of the different types of green surfactants marketed in the world
Evolution of the Far-Infrared-Radio Correlation and Infrared SEDs of Massive Galaxies over z = 0 - 2
We investigate the far-infrared-radio correlation (FRC) of
stellar-mass-selected galaxies in the Extended Chandra Deep Field South using
far-infrared imaging from Spitzer and radio imaging from the Very Large Array
and Giant Metre-Wave Radio Telescope. We stack in redshift bins to probe
galaxies below the noise and confusion limits. Radio fluxes are K-corrected
using observed flux ratios, leading to tentative evidence for an evolution in
spectral index. We compare spectral energy distribution (SED) templates of
local galaxies for K-correcting FIR fluxes, and show that the data are best fit
by a quiescent spiral template (M51) rather than a warm starburst (M82) or
ULIRG (Arp220), implying a predominance of cold dust in massive galaxies at
high redshift. In contrast we measure total infrared luminosities that are
consistent with high star-formation rates. We observe that the FRC index (q)
does not evolve significantly over z=0-2 when computed from K-corrected 24 or
160-mum photometry, but that using 70-mum fluxes leads to an apparent decline
in q beyond z~1. This suggests some change in the SED at high redshift, either
a steepening of the spectrum at rest-frame ~25-35mum or a deficiency at ~70mum
leading to a drop in the total infrared/radio ratios. We compare our results to
other work in the literature and find synergies with recent findings on the
high-redshift FRC, high specific star-formation rates of massive galaxies and
the cold dust temperatures in these galaxies.Comment: 21 pages, 13 figures, accepted for publication in MNRA
Properties of the molecular gas in a starbursting QSO at z=1.83 in the COSMOS field
Using the IRAM 30m telescope, we have detected the CO J=2-1, 4-3, 5-4, and
6-5 emission lines in the millimeter-bright, blank-field selected AGN COSMOS
J100038+020822 at redshift z=1.8275. The sub-local thermodynamic equilibrium
(LTE) excitation of the J=4 level implies that the gas is less excited than
that in typical nearby starburst galaxies such as NGC253, and in the
high-redshift quasars studied to date, such as J1148+5251 or BR1202-0725. Large
velocity gradient (LVG) modeling of the CO line spectral energy distribution
(CO SED; flux density vs. rotational quantum number) yields H2 densities in the
range 10^{3.5}--10^{4.0} cm-3, and kinetic temperatures between 50 K and 200 K.
The H2 mass of (3.6 - 5.4) x 10^{10} M_sun implied by the line intensities
compares well with our estimate of the dynamical mass within the inner 1.5 kpc
of the object. Fitting a two-component gray body spectrum, we find a dust mass
of 1.2 x 10^{9} M_sun, and cold and hot dust temperatures of 42+/-5 K and
160+/-25 K, respectively. The broad MgII line allows us to estimate the mass of
the central black hole as 1.7 x 10^{9} M_sun. Although the optical spectrum and
multi-wavelength SED matches those of an average QSO, the molecular gas content
and dust properties resemble those of known submillimeter galaxies (SMGs). The
optical morphology of this source shows tidal tails that suggest a recent
interaction or merger. Since it shares properties of both starburst and AGN,
this object appears to be in a transition from a strongly starforming
submillimeter galaxy to a QSO.Comment: Accepted for publication in Astronomy & Astrophysics (A&A
Unveiling the Nature of Submillimeter Galaxy SXDF850.6
We present an 880 micron Submillimeter Array (SMA) detection of the
submillimeter galaxy SXDF850.6. SXDF850.6 is a bright source (S(850 micron) = 8
mJy) detected in the SCUBA Half Degree Extragalactic Survey (SHADES), and has
multiple possible radio counterparts in its deep radio image obtained at the
VLA. Our new SMA detection finds that the submm emission coincides with the
brightest radio emission that is found ~8" north of the coordinates determined
from SCUBA. Despite the lack of detectable counterparts in deep UV/optical
images, we find a source at the SMA position in near-infrared and longer
wavelength images. We perform SED model fits to UV-optical-IR photometry (u, B,
V, R, i', z', J, H, K, 3.6 micron, 4.5 micron, 5.8 micron, and 8.0 micron) and
to submm-radio photometry (850 micron, 880 micron, 1100 micron, and 21 cm)
independently, and we find both are well described by starburst templates at a
redshift of z ~= 2.2 (+/- 0.3). The best-fit parameters from the UV-optical-IR
SED fit are a redshift of z = 1.87 (+0.15/-0.07), a stellar mass of M_star =
2.5 +2.2/-0.3 x 10^11 M_sun, an extinction of A_V = 3.0 (+0.3/-1.0) mag, and an
age of 720 (+1880/-210) Myr. The submm-radio SED fit provides a consistent
redshift of z ~ 1.8-2.5, an IR luminosity of L_IR = (7-26) x 10^12 L_sun, and a
star formation rate of 1300-4500 M_sun/yr. These results suggest that SXDF850.6
is a mature system already having a massive amount of old stellar population
constructed before its submm bright phase and is experiencing a dusty
starburst, possibly induced by major mergers.Comment: 7 pages, 5 figures, Accepted for publication in Astrophysical Journa
Starburst and cirrus models for submillimeter galaxies
We present radiative transfer models for submillimeter galaxies with
spectroscopic redshifts and mid-infrared spectroscopy from Spitzer/IRS and
analyze available Spitzer/MIPS 24, 70 and 160mu data. We use two types of
starburst models, a cirrus model and a model for the emission of an AGN torus
in order to investigate the nature of these objects. We find that for three of
the objects (25%) cirrus emission alone can account for the mid-infrared
spectrum and the MIPS and submillimeter data. For the remaining objects we find
that we need a combination of starburst and cirrus in order to fit
simultaneously the multi--wavelength data.
We find that the typical submillimeter galaxy has comparable luminosity in
the starburst (median L=10^12.5 Lo) and cirrus (median L=10^12.4 Lo)
components. This could arise if the galaxies have been forming stars
continuously for the last 250Myr with the star formation occurring in the last
5Myr being shrouded by high-optical-depth molecular cloud dust, whereas the
rest of the starlight is attenuated by diffuse dust or cirrus with an Av of
about 1mag.Comment: 9 pages, AA accepte
Millimeter imaging of submillimeter galaxies in the COSMOS field: Redshift distribution
We present new IRAM PdBI 1.3mm continuum observations at ~1.5" resolution of
28 SMGs previously discovered with the 870um bolometer LABOCA at APEX within
the central 0.7deg2 of the COSMOS field. 19 out of the 28 LABOCA sources were
detected with the PdBI at a >~3sigma level of ~1.4mJy/b. A combined analysis of
this new sample with existing interferometrically identified SMGs in the COSMOS
field yields the following results: 1) >~15%, and possibly up to ~40% of
single-dish detected SMGs consist of multiple sources, 2) statistical
identifications of multi-wavelength counterparts to the single-dish SMGs yield
that only ~50% of these single-dish SMGs have real radio or IR counterparts, 3)
~18% of interferometric SMGs have only radio or even no multi-wavelength
counterpart at all, and 4) ~50-70% of z>~3 SMGs have no radio counterparts down
to an rms of 7-12uJy at 1.4GHz. Using the exact interferometric positions to
identify proper multi-wavelength counterparts allows us to determine accurate
photometric redshifts for these sources. The redshift distributions of the
combined and the individual 1.1mm and 870um selected samples have a higher mean
and broader width than the redshift distributions derived in previous studies.
Our sample supports the previous tentative trend that on average brighter
and/or mm-selected SMGs are located at higher redshifts. There is a tentative
offset between the mean redshift for the 1.1mm (=3.1+/-0.4) and 870um
(=2.6+/-0.4) selected samples, with the 1.1mm sources lying on average at
higher redshifts. Based on our nearly complete sample of AzTEC 1.1mm SMGs
within a uniform 0.15deg2 area we infer a higher surface density of z>~4 SMGs
than predicted by current cosmological models. In summary, our findings imply
that (sub-)millimeter interferometric identifications are crucial to build
statistically complete and unbiased samples of SMGs.Comment: 35 pages, 18 figures, 10 tables; accepted for publication in A&
Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - I. Source catalogue and number counts
[Abridged] We present the first results from a 1.1 mm confusion-limited map
of the GOODS-S field taken with AzTEC on the ASTE telescope. We imaged a 270
sq. arcmin field to a 1\sigma depth of 0.48 - 0.73 mJy/beam, making this one of
the deepest blank-field surveys at mm-wavelengths ever achieved. Although our
GOODS-S map is extremely confused, we demonstrate that our source
identification and number counts analyses are robust, and the techniques
discussed in this paper are relevant for other deeply confused surveys. We find
a total of 41 dusty starburst galaxies with S/N >= 3.5 within this uniformly
covered region, where only two are expected to be false detections. We derive
the 1.1mm number counts from this field using both a "P(d)" analysis and a
semi-Bayesian technique, and find that both methods give consistent results.
Our data are well-fit by a Schechter function model with (S', N(3mJy), \alpha)
= (1.30+0.19 mJy, 160+27 (mJy/deg^2)^(-1), -2.0). Given the depth of this
survey, we put the first tight constraints on the 1.1 mm number counts at
S(1.1mm) = 0.5 mJy, and we find evidence that the faint-end of the number
counts at S(850\mu m) < 2.0 mJy from various SCUBA surveys towards lensing
clusters are biased high. In contrast to the 870 \mu m survey of this field
with the LABOCA camera, we find no apparent under-density of sources compared
to previous surveys at 1.1 mm. Additionally, we find a significant number of
SMGs not identified in the LABOCA catalogue. We find that in contrast to
observations at wavelengths < 500 \mu m, MIPS 24 \mu m sources do not resolve
the total energy density in the cosmic infrared background at 1.1 mm,
demonstrating that a population of z > 3 dust-obscured galaxies that are
unaccounted for at these shorter wavelengths potentially contribute to a large
fraction (~2/3) of the infrared background at 1.1 mm.Comment: 21 pages, 9 figures. Accepted to MNRAS
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