102 research outputs found
Aquisições públicas em Cabo Verde: desafios e potencialidades para promover o desenvolvimento rural
Este trabalho tem por objectivo verificar os desafios e oportunidades existentes na ligação entre o Programa de Alimentação Escolar e produção local em Cabo Verde. Entrevistas semi-estruturadas, observação in loco e dados secundários foram utilizados para coleta de dados. Constatou-se a necessidade de mudanças estruturais do Programa, descentralizando as compras públicas, introduzindo produtos locais no menu e melhorando as condições físicas das cozinhas e armazéns. Relativamente à produção, é possível afirmar que há quantidade suficiente para abastecimento, mas deficiências no processamento, escoamento e comercialização, com necessidade de investimentos em extensão rural, organização dos agricultores e crédito rural. Considera-se que a descentralização das compras poderia desonerar o Estado em relação aos custos com a logística e facilitar as aquisições dos produtores locais, tornando o Programa sustentável e vector de desenvolvimento.This work aims at studying the challenges and opportunities in this connection between School Feeding Program and local agriculture in Cape Verde. Semi-structured interviews, observation and secondary data were used for data collection. It was noted the need for structural changes of Program, decentralizing public procurement by introducing local products on the menu and improving the physical condition of kitchens and warehouses. On the side of the production, there is sufficient quantity to supply, but deficiencies in the processing, distribution and marketing, requiring investments in agricultural extension, organization of farmers and rural credit. It is considered that the decentralization of food procurement would relieve the State in relation to the cost of logistics, the Program would becoming sustainable and a vector of development
Fruits, Frugivores, and the Evolution of Phytochemical Diversity
Plants produce an enormous diversity of secondary metabolites, but the evolutionary mechanisms that maintain this diversity are still unclear. The interaction diversity hypothesis suggests that complex chemical phenotypes are maintained because different metabolites benefit plants in different pairwise interactions with a diversity of other organisms. In this synthesis, we extend the interaction diversity hypothesis to consider that fruits, as potential hotspots of interactions with both antagonists and mutualists, are likely important incubators of phytochemical diversity. We provide a case study focused on the Neotropical shrub Piper reticulatum that demonstrates: 1) secondary metabolites in fruits have complex and cascading effects for shaping the outcome of both mutualistic and antagonistic fruit–frugivore interactions, and; 2) fruits can harbor substantially higher levels of phytochemical diversity than leaves, even though leaves have been the primary focus of plant chemical ecology research for decades. We then suggest a number of research priorities for integrating chemical ecology with fruit–frugivore interaction research and make specific, testable predictions for patterns that should emerge if fruit interaction diversity has helped shape phytochemical diversity. Testing these predictions in a range of systems will provide new insight into the mechanisms driving frugivory and seed dispersal and shape an improved, whole-plant perspective on plant chemical trait evolution
Les Pédo-paysages des plaines centrales de Midi-Pyrénées
Les sols des zones de plaines de la région Midi-Pyrénées montrent une grande diversité liée, notamment, au carrefour des influences climatiques passées et actuelles : glaciaire, méditerranéenne et atlantique. Le présent article illustre la distribution des principales Unités Typologiques de Sols parmi les Unités pédo-paysagères dans les zones de plaines depuis le nord du Lot jusqu'au piémont ariégeois. La couverture pédologique y est très marquée par la nature des grands ensembles sédimentaires, depuis les contreforts du Massif central, jusqu'à la Molasse argilo-calcaire très largement étendue dans le bassin toulousain
Conditions of emergence of the Sooty Bark Disease and aerobiology of Cryptostroma corticale in Europe
The sooty bark disease (SBD) is an emerging disease affecting sycamore maple trees (Acer pseudoplatanus) in Europe. Cryptostroma corticale, the causal agent, putatively native to eastern North America, can be also pathogenic for humans causing pneumonitis. It was first detected in 1945 in Europe, with markedly increasing reports since 2000. Pathogen development appears to be linked to heat waves and drought episodes. Here, we analyse the conditions of the SBD emergence in Europe based on a three-decadal time -series data set. We also assess the suitability of aerobiological samples using a species-specific quantitative PCR assay to inform the epidemiology of C. corticale, through a regional study in France comparing two-year aerobiological and epidemiological data, and a continental study including 12 air samplers from six countries (Czechia, France, Italy, Portugal, Sweden and Switzerland). We found that an accumulated water deficit in spring and summer lower than-132 mm correlates with SBD outbreaks. Our results suggest that C. corticale is an efficient airborne pathogen which can dis-perse its conidia as far as 310 km from the site of the closest disease outbreak. Aerobiology of C. corticale followed the SBD distribution in Europe. Pathogen detection was high in countries within the host native area and with longer disease presence, such as France, Switzerland and Czech Republic, and sporadic in Italy, where the pathogen was reported just once. The pathogen was absent in samples from Portugal and Sweden, where the disease has not been reported yet. We conclude that aerobiological surveillance can inform the spatial distribution of the SBD, and contribute to early detection in pathogen-free countries
Conditions of emergence of the Sooty Bark Disease and aerobiology of Cryptostroma corticale in Europe
The sooty bark disease (SBD) is an emerging disease affecting sycamore maple trees (Acer pseudoplatanus)
in Europe. Cryptostroma corticale, the causal agent, putatively native to eastern North America, can be
also pathogenic for humans causing pneumonitis. It was first detected in 1945 in Europe, with markedly
increasing reports since 2000. Pathogen development appears to be linked to heat waves and drought
episodes. Here, we analyse the conditions of the SBD emergence in Europe based on a three-decadal time-
series data set. We also assess the suitability of aerobiological samples using a species-specific quantitative
PCR assay to inform the epidemiology of C. corticale, through a regional study in France comparing two-
year aerobiological and epidemiological data, and a continental study including 12 air samplers from six
countries (Czechia, France, Italy, Portugal, Sweden and Switzerland).
We found that an accumulated water deficit in spring and summer lower than -132 mm correlates
with SBD outbreaks. Our results suggest that C. corticale is an efficient airborne pathogen which can dis-
perse its conidia as far as 310 km from the site of the closest disease outbreak. Aerobiology of C. corticale
followed the SBD distribution in Europe. Pathogen detection was high in countries within the host native
area and with longer disease presence, such as France, Switzerland and Czech Republic, and sporadic in
Italy, where the pathogen was reported just once. The pathogen was absent in samples from Portugal and
Sweden, where the disease has not been reported yet. We conclude that aerobiological surveillance can
inform the spatial distribution of the SBD, and contribute to early detection in pathogen-free countriesinfo:eu-repo/semantics/publishedVersio
The gp38 Adhesins of the T4 Superfamily: A Complex Modular Determinant of the Phage’s Host Specificity
The tail fiber adhesins are the primary determinants of host range in the T4-type bacteriophages. Among the indispensable virion components, the sequences of the long tail fiber genes and their associated adhesins are among the most variable. The predominant form of the adhesin in the T4-type phages is not even the version of the gene encoded by T4, the archetype of the superfamily, but rather a small unrelated protein (gp38) encoded by closely related phages such as T2 and T6. This gp38 adhesin has a modular design: its N-terminal attachment domain binds at the tip of the tail fiber, whereas the C-terminal specificity domain determines its host receptor affinity. This specificity domain has a series of four hypervariable segments (HVSs) that are separated by a set of highly conserved glycine-rich motifs (GRMs) that apparently form the domain’s conserved structural core. The role of gp38’s various components was examined by a comparative analysis of a large series of gp38 adhesins from T-even superfamily phages with differing host specificities. A deletion analysis revealed that the individual HVSs and GRMs are essential to the T6 adhesin’s function and suggests that these different components all act in synergy to mediate adsorption. The evolutionary advantages of the modular design of the adhesin involving both conserved structural elements and multiple independent and easily interchanged specificity determinants are discussed
Exploring marine ecosystems with elementary school Portuguese children: inquiry-based project activities focused on ‘real-life’ contexts
The purpose of the study was to investigate how young students engage in an inquirybased
project driven by real-life contexts. Elementary school children were engaged in a
small inquiry project centred on marine biodiversity and species adaptations. All
activities included the exploration of an out-of-school setting as a learning context. A
total of 49 students and 2 teachers were involved in the activities. The research
methods included observation, document analysis and content analysis of the answers
to a questionnaire and an interview. The results revealed that most of the students
acquired scientific knowledge related to biological diversity and adaptations to
habitat. Moreover, students progressively demonstrate greater autonomy,
argumentative ability and decision-making. One implication of the present study is
that elementary science curriculum could be better managed with inquiry projectbased
activities that explore different types of resources and out-of-school settings.info:eu-repo/semantics/publishedVersio
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Future evolution of the Sahel precipitation zonal contrast in CESM1
The main focus of this study is the zonal contrast of the Sahel precipitation shown in the CMIP5 climate projections: precipitation decreases over the western Sahel (i.e., Senegal and western Mali) and increases over the central Sahel (i.e., eastern Mali, Burkina Faso and Niger). This zonal contrast in future precipitation change is a robust model response to climate change but suffers from a lack of an explanation. To this aim, we study the impact of current and future climate change on Sahel precipitation by using the Large Ensemble of the Community Earth System Model version 1 (CESM1). In CESM1, global warming leads to a strengthening of the zonal contrast, as shown by the difference between the 2060–2099 period (under a high emission scenario) and the 1960–1999 period (under the historical forcing). The zonal contrast is associated with dynamic shifts in the atmospheric circulation. We show that, in absence of a forced response, that is, when only accounting for internal climate variability, the zonal contrast is associated with the Pacific and the tropical Atlantic oceans variability. However, future patterns in sea surface temperature (SST) anomalies are not necessary to explaining the projected strengthening of the zonal contrast. The mechanisms underlying the simulated changes are elucidated by analysing a set of CMIP5 idealised simulations. We show the increase in precipitation over the central Sahel to be mostly associated with the surface warming over northern Africa, which favour the displacement of the monsoon cell northwards. Over the western Sahel, the decrease in Sahel precipitation is associated with a southward shift of the monsoon circulation, and is mostly due to the warming of the SST. These two mechanisms allow explaining the zonal contrast in precipitation change
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Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5 μm to 12 μm with the JWST’s Mid-Infrared Instrument. The spectra reveal a large day–night temperature contrast (with average brightness temperatures of 1,524 ± 35 K and 863 ± 23 K, respectively) and evidence for water absorption at all orbital phases. Comparisons with three-dimensional atmospheric models show that both the phase-curve shape and emission spectra strongly suggest the presence of nightside clouds that become optically thick to thermal emission at pressures greater than ~100 mbar. The dayside is consistent with a cloudless atmosphere above the mid-infrared photosphere. Contrary to expectations from equilibrium chemistry but consistent with disequilibrium kinetics models, methane is not detected on the nightside (2σ upper limit of 1–6 ppm, depending on model assumptions). Our results provide strong evidence that the atmosphere of WASP-43b is shaped by disequilibrium processes and provide new insights into the properties of the planet’s nightside clouds. However, the remaining discrepancies between our observations and our predictive atmospheric models emphasize the importance of further exploring the effects of clouds and disequilibrium chemistry in numerical models.Peer reviewe
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