The relationships between organic farming and agroecology.

While acknowledging an extension of agroecology in the organic sector and a growing influence of agroecology in the academic world, we explore their relationships. These relationships cannot be reduced to an opposition between a scientific field and a practical domain. A Brazilian case study based on the analysis of researchers and social actors trajectories exemplifies the diversity of existing relations, whether inclusive or exclusive. With a literature review, this allows characterising the specific attributes of both organic agriculture and agroecology. We discuss them in the light of current challenges for organic farming research and development

Stellar luminosity functions of rich star clusters in the Large Magellanic Cloud

We show the results of deep V and I HST photometry of 6 rich star clusters in the Large Magellanic Cloud with different ages and metallicities. The number of stars with measured magnitudes in each cluster varies from about 3000 to 10000. We build stellar density and surface brightness profiles for the clusters and extract half-light radii and other structural parameters for each. We also obtain luminosity functions, Phi (Mv), down to Mv ~ 6 (m/msun > 0.6), and investigate their dependence with distance from the cluster centre well beyond their half-light radius. In all clusters we find a systematic increase in the luminosity function slope with radial distance from the centre. Among the clusters displaying significant mass segregation are the two youngest in the sample: NGC 1805 and NGC 1818. For these two clusters we obtain present-day mass functions. The NGC 1818 mass function is in excellent agreement with that derived by other authors, also using HST data. They young cluster mass function slopes differ, that of NCG 1805 being systematically steeper than NGC 1818. Since these are very young stellar systems (age < 40 Myrs), these variations may reflect the initial conditions rather than evolution due to internal dynamics.Comment: 10 pages, 24 figure

The New Tendencies of Environmental Impact Assessment of Livestock Production: A Road Testing of LEAP/FAO Biodiversity Assessment Guidelines in Pastoral Systems in Uruguay

After the publication of the “long shadow of cattle” report, ruminant production systems have received great pressure for their contributions in greenhouse gases (GHG). However, the environmental effects of human activities are much broader than GHG production and in some cases, there are positive contributions. In order to broaden the environmental perspective and with the encouragement of governments, the private sector and NGOs, LEAP-FAO has developed environmental assessment guidelines for the world\u27s livestock production systems. This paper presents a road-testing of the Biodiversity Assessment Guideline at farm scale for six case studies in pastoral livestock systems in Uruguay. The producers involved correspond to farmers with a mixed livestock system (cows and sheep) with a full cycle and areas ranging between 2000 and 5000 hectares. Three of the farms have production based 100% on natural grasslands, while the other three had 30% of their area with sown pastures. The application of the guide at local level implies the use of the system of pressure, state and response indicators (PSR). The recommendation of the guide in its public review version requires a minimum set of 24 indicators, which can also be divided into several measurable variables. The results obtained in this study showed that the complete set is a reliable tool to evaluate the functioning of the systems in terms of their contribution to biodiversity conservation. However, some are more sensitive than others to evaluate changes depending on the scale. For example, the change in land use due to planting of forage crops clearly affects birds and arthropods such as spiders; though, due to scale of habitat use is less clear the global effect in bird population. The state indicators related to richness and diversity of species from different taxonomic groups is very relevant but result the more expensive issue in the assessment. Global indicators as the Ecosystem Integrity Index (EII) show a consistent effect of intensification but the connectivity in the actual percentages of natural grassland substitution is still good

Spanish statistical parametric speech synthesis using a neural vocoder

During the 2000s decade, unit-selection based text-to-speech was the dominant commercial technology. Meanwhile, the TTS research community has made a big effort to push statistical-parametric speech synthesis to get similar quality and more flexibility on the synthetically generated voice. During last years, deep learning advances applied to speech synthesis have filled the gap, specially when neural vocoders substitute traditional signal-processing based vocoders. In this paper we propose to substitute the waveform generation vocoder of MUSA, our Spanish TTS, with SampleRNN, a neural vocoder which was recently proposed as a deep autoregressive raw waveform generation model. MUSA uses recurrent neural networks to predict vocoder parameters (MFCC and logF0) from linguistic features. Then, the Ahocoder vocoder is used to recover the speech waveform out of the predicted parameters. In the first system SampleRNN is extended to generate speech conditioned on the Ahocoder generated parameters (mfcc and logF0), where two configurations have been considered to train the system. First, the parameters derived from the signal using Ahocoder are used. Secondly, the system is trained with the parameters predicted by MUSA, where SampleRNN and MUSA are jointly optimized. The subjective evaluation shows that the second system outperforms both the original Ahocoder and SampleRNN as an independent neural vocoder.Peer ReviewedPostprint (published version

The Milky Way bar and bulge revealed by APOGEE and Gaia EDR3

We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner Galactic sample has more than 26 500 stars within |XGal| < 5 kpc, |YGal| < 3.5 kpc, |ZGal| < 1 kpc, and we also carry out the analysis for a foreground-cleaned subsample of 8000 stars that is more representative of the bulge–bar populations. These samples allow us to build chemo-dynamical maps of the stellar populations with vastly improved detail. The inner Galaxy shows an apparent chemical bimodality in key abundance ratios [α/Fe], [C/N], and [Mn/O], which probe different enrichment timescales, suggesting a star formation gap (quenching) between the high- and low-α populations. Using a joint analysis of the distributions of kinematics, metallicities, mean orbital radius, and chemical abundances, we can characterize the different populations coexisting in the innermost regions of the Galaxy for the first time. The chemo-kinematic data dissected on an eccentricity–|Z|max plane reveal the chemical and kinematic signatures of the bar, the thin inner disc, and an inner thick disc, and a broad metallicity population with large velocity dispersion indicative of a pressure-supported component. The interplay between these different populations is mapped onto the different metallicity distributions seen in the eccentricity–|Z|max diagram consistently with the mean orbital radius and Vφ distributions. A clear metallicity gradient as a function of |Z|max is also found, which is consistent with the spatial overlapping of different populations. Additionally, we find and chemically and kinematically characterize a group of counter-rotating stars that could be the result of a gas-rich merger event or just the result of clumpy star formation during the earliest phases of the early disc that migrated into the bulge. Finally, based on 6D information, we assign stars a probability value of being on a bar orbit and find that most of the stars with large bar orbit probabilities come from the innermost 3 kpc, with a broad dispersion of metallicity. Even stars with a high probability of belonging to the bar show chemical bimodality in the [α/Fe] versus [Fe/H] diagram. This suggests bar trapping to be an efficient mechanism, explaining why stars on bar orbits do not show a significant, distinct chemical abundance ratio signature

Carência de macronutrientes em plantas de quina.

bitstream/item/32781/1/CPATU-BP192.pd

AE Aurigae: first detection of non-thermal X-ray emission from a bow shock produced by a runaway star

Runaway stars produce shocks when passing through interstellar medium at supersonic velocities. Bow shocks have been detected in the mid-infrared for several high-mass runaway stars and in radio waves for one star. Theoretical models predict the production of high-energy photons by non-thermal radiative processes in a number sufficiently large to be detected in X-rays. To date, no stellar bow shock has been detected at such energies. We present the first detection of X-ray emission from a bow shock produced by a runaway star. The star is AE Aur, which was likely expelled from its birthplace by the encounter of two massive binary systems and now is passing through the dense nebula IC 405. The X-ray emission from the bow shock is detected at 30" to the northeast of the star, coinciding with an enhancement in the density of the nebula. From the analysis of the observed X-ray spectrum of the source and our theoretical emission model, we confirm that the X-ray emission is produced mainly by inverse Compton upscattering of infrared photons from dust in the shock front.Comment: Accepted for publication in the Astrophysical Journal with number ApJ, 757, L6. Four figure

Sintomas de deficiências de macronutrientes em plantas de jaborandi (Pilocarpus microphyllus Starf.).

bitstream/item/57703/1/CPATU-ComTec84.pd