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.

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    [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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