45 research outputs found
Expansão da agricultura orgânica e os desafios enfrentados por produtores brasileiros na produção e exportação de orgânicos
A agricultura orgânica baseia-se no uso de métodos de cultivos ecológicos, alternativos à agricultura convencional, com o intuito de preservar o meio ambiente. A expansão do mercado mundial de produtos orgânicos decorreu da preocupação com a degradação ambiental e com a segurança do alimento. Entretanto, os produtores orgânicos brasileiros enfrentam desafios tanto no processo produtivo quanto para acessarem o mercado internacional orgânico. Neste contexto, o objetivo deste estudo foi analisar a evolução da produção orgânica e os desafios para produção e exportação dos produtos orgânicos brasileiros, particularmente para o mercado europeu. Para analisar a evolução da produção orgânica foram coletados dados do Instituto Brasileiro de Geografia e Estatística (IBGE), Ministério da Agricultura, Pecuária e Abastecimento (MAPA) e Research Institute of Organic Agriculture (FiBL) sobre a área agropecuária, número de estabelecimentos e de produtores, vendas no varejo, consumo per capita e exportações. Os dados disponíveis mostraram o crescimento contínuo da produção orgânica mundial entre 2000 e 2018. A análise do comércio mundial de orgânicos foi realizada por meio do Modelo Gravitacional. A equação gravitacional estimada utilizou como variável dependente as exportações mundiais de orgânicos. Já as variáveis independentes foram: o Produto Interno Bruto (PIB) e a população dos países exportadores de orgânicos, o PIB e a população da América do Norte e União Europeia, além da área agrícola destinada à produção orgânica tanto dos países exportadores quanto da América do Norte e União Europeia. De acordo com o resultado do modelo, as variáveis determinantes das exportações de orgânicos foram o PIB dos países exportadores, bem como o PIB, a população e a área agrícola orgânica da América do Norte e da União Europeia. Além disso, também foram realizadas entrevistas com agricultores familiares orgânicos brasileiros a fim de investigar os desafios que estes produtores tem encontrado na produção e comercialização de orgânicos. Eles responderam questões relacionadas à produção de orgânicos, aos desafios enfrentados, à importância das políticas públicas para o setor, à certificação e ao acesso ao mercado europeu. Em relação às dificuldades na produção, mencionaram fatores como alto custo e burocracia da certificação, falta de pagamento diferenciado pelo produto orgânico e indisponibilidade de insumos orgânicos. Já em relação aos desafios para exportação para o mercado orgânico europeu, relataram problemas como a falta de conhecimento do processo de exportação, dificuldade na obtenção da certificação orgânica europeia, falta de conhecimento da legislação orgânica europeia e do mercado europeu, bem como a escala de produção para exportação. Os produtores entrevistados consideram as políticas públicas importantes para o desenvolvimento da agricultura orgânica no Brasil, mas que necessitam ser aprimoradas para atender as necessidades dos produtores familiares orgânicos
Constraints on the CMB temperature redshift dependence from SZ and distance measurements
The relation between redshift and the CMB temperature,
is a key prediction of standard cosmology, but is violated in many non-standard
models. Constraining possible deviations to this law is an effective way to
test the CDM paradigm and search for hints of new physics. We present
state-of-the-art constraints, using both direct and indirect measurements. In
particular, we point out that in models where photons can be created or
destroyed, not only does the temperature-redshift relation change, but so does
the distance duality relation, and these departures from the standard behaviour
are related, providing us with an opportunity to improve constraints. We show
that current datasets limit possible deviations of the form
to be up to a redshift
. We also discuss how, with the next generation of space and
ground-based experiments, these constraints can be improved by more than one
order of magnitude.Comment: 27 pages, 11 figure
Long-acting bronchodilators improve exercise capacity in COPD patients : a systematic review and meta-analysis
Background: We carried out a systematic review and meta-analysis with the aim to evaluate the efficacy of long-acting bronchodilators on exercise capacity in COPD patients. Methods: The endpoints were the efficacy of long-acting bronchodilators (altogether, and by single classes) vs. placebo in modifying endurance time (ET), inspiratory capacity (IC) and dyspnea during exercise, taking into consideration the outcomes according to different patients' inclusion criteria and exercise methodology. Results: Twenty-two studies were deemed eligible for analysis. Weighted mean increase in ET resulted of 67 s (95% CI ranges from 55 to 79). For isotime IC and dyspnea during exercise, weighted improvements were 195 ml (162-229), and - 0.41 units (- 0.56 to - 0.27), respectively. The increase in trough IC was 157 ml (138-175). We found a trend in favour of LAMA compared to LABA in terms of ET. In the 11 studies which reported a value of functional residual capacity > 120% as inclusion criterion, weighted mean increase in endurance time was 94 s (65 to 123); however we did not find any significant correlation between ET and mean trough IC (P: 0.593). The improvement of ET in the 5 studies using walking as exercise methodology resulted of 58 s (- 4 to 121). Conclusions: Long-acting bronchodilators improve exercise capacity in COPD. The main effect of long-acting bronchodilators seems to be a decrease of basal IC rather than a modification of dynamic hyperinflation during exercise. The efficacy in terms of endurance time seems higher in studies which enrolled patients with hyperinflation, with a similar efficacy on walking or cycling
Nonthermal phenomena in clusters of galaxies
Recent observations of high energy (> 20 keV) X-ray emission in a few
clusters of galaxies broaden our knowledge of physical phenomena in the
intracluster space. This emission is likely to be nonthermal, probably
resulting from Compton scattering of relativistic electrons by the cosmic
microwave background (CMB) radiation. Direct evidence for the presence of
relativistic electrons in some 50 clusters comes from measurements of extended
radio emission in their central regions. We briefly review the main results
from observations of extended regions of radio emission, and Faraday rotation
measurements of background and cluster radio sources. The main focus of the
review are searches for nonthermal X-ray emission conducted with past and
currently operating satellites, which yielded appreciable evidence for
nonthermal emission components in the spectra of a few clusters. This evidence
is clearly not unequivocal, due to substantial observational and systematic
uncertainties, in addition to virtually complete lack of spatial information.
If indeed the emission has its origin in Compton scattering of relativistic
electrons by the CMB, then the mean magnetic field strength and density of
relativistic electrons in the cluster can be directly determined. Knowledge of
these basic nonthermal quantities is valuable for the detailed description of
processes in intracluster gas and for the origin of magnetic fields.Comment: 23 pages, 7 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 5; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
Phylogenomics and the rise of the angiosperms
Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5,6,7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade
Panpipes as units of cultural analysis and dispersal
© 2020 The Author(s). The panpipe is a musical instrument composed of end-blown tubes of different lengths tied together. They can be traced back to the Neolithic, and they have been found at prehistoric sites in China, Europe and South America. Panpipes display substantial variation in space and time across functional and aesthetic dimensions. Finding similarities in panpipes that belong to distant human groups poses a challenge to cultural evolution: While some have claimed that their relative simplicity speaks for independent inventions, others argue that strong similarities of specific features in panpipes from Asia, Oceania and South America suggest long-distance diffusion events. We examined 20 features of a worldwide sample of 401 panpipes and analysed statistically whether instrument features can successfully be used to determine provenance. The model predictions suggest that panpipes are reliable provenance markers, but we found an unusual classification error in which Melanesian panpipes are predicted as originating in South America. Although this pattern may be signalling a diffusion event, other factors such as convergence and preservation biases may play a role. Our analyses show the potential of cultural evolution research on music that incorporates material evidence, which in this study includes both archaeological and ethnographic samples preserved in museum collections
An Official American Thoracic Society/European Respiratory Society Policy Statement : Disparities in Respiratory Health
Background: Health disparities, defined as a significant difference in
health between populations, are more common for diseases of the respiratory system than for those of other organ systems, because of the environmental influence on breathing and the variation of the environment among different segments of the population. The lowest social groups are up to 14 times more likely to have respiratory
diseases than are the highest. Tobacco smoke, air pollution, environmental
exposures, and occupational hazards affect the lungs more than other organs, and occur disproportionately in ethnic minorities and those with lower socioeconomic status. Lack of access to quality health care contributes to disparities.
Methods: The executiv ecommittees of the American Thoracic Society (ATS) and European Respiratory Society (ERS) established a writing committee to develop a policy on health disparities. The document was reviewed, edited, and approved by the full executive committees and boards of directors of the societies.
Results: This document expresses a policy to address health disparities
by promoting scientific inquiry and training, disseminating medical information and best practices, and monitoring and advocating for public respiratory health. ERS and ATS have strong international commitments, and work with leaders from governments academia, and organizations to address and reduce avoidable health inequalities. Their training initiatives improve the function of health care systems and health equality. Both the ATS and ERS support all aspects of this document, confer regularly, and act together when
possible, but the activities to bring about change may vary because of the differences in the continents where the two organizations carry out most of their activities.
Conclusions: The ATS and ERS pledge to frame their actions to reduce respiratory health disparities. The vision of the ATS and ERS is that all
persons attain better and sustained respiratory health. They call on
all their members and other societies to join in this commitment
An official American Thoracic Society and European Respiratory Society policy statement : disparities in respiratory health
Health disparities, defined as a significant difference in health between populations, are more common for diseases of the respiratory system than for those of other organ systems, because of the environmental influence on breathing and the variation of the environment among different segments of the population. The lowest social groups are up to 14 times more likely to have respiratory diseases than are the highest. Tobacco smoke, air pollution, environmental exposures, and occupational hazards affect the lungs more than other organs and occur disproportionately in ethnic minorities and those with lower socioeconomic status. Lack of access to quality healthcare contributes to disparities. The executive committees of the American Thoracic Society (ATS) and European Respiratory Society (ERS) established a writing committee to develop a policy on health disparities. The document was reviewed, edited, and approved by their full executive committees and boards of directors of the societies. This document expresses a policy to address health disparities by promoting scientific inquiry and training, disseminating medical information and best practices, and monitoring and advocating for public respiratory health. The ERS and the ATS have strong international commitments and work with leaders from governments, academia, and other organisational bodies to address and reduce avoidable health inequalities. Their training initiatives improve the function of healthcare systems and health equality. Both the ATS and the ERS support all aspects of this document, confer regularly, and act together when possible, but the activities to bring about change may vary because of the differences in the continents where the two organisations carry out most of their activities. The ATS and ERS pledge to frame their actions to reduce respiratory health disparities. The vision of the ATS and ERS is that all persons attain better and sustained respiratory health. They call on all their members and other societies to join in this commitment. Copyrigh