1,008 research outputs found
Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome
A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems was carried out, followed by a participatory systematisation of the farmers experiences. Our objective was to identify the main tree species used by farmers as well as their criteria for selecting or rejecting tree species. Furthermore, we aimed to present a specific inventory of trees of the Leguminosae family. In order to collect the data, we reviewed the bibliography of the participatory trial, visited and interviewed the farmers and organised workshops with them. The main farmers' criteria for selecting tree species were compatibility with coffee, amount of biomass, production and the labour needed for tree management. The farmers listed 85 tree species; we recorded 28 tree species of the Leguminosae family. Most trees were either native to the biome or exotic fruit trees. In order to design and manage complex agroforestry systems, family farmers need sufficient knowledge and autonomy, which can be reinforced when a participatory methodology is used for developing on-farm agroforestry systems. In the case presented, the farmers learned how to manage, reclaim and conserve their land. The diversification of production, especially with fruit, contributes to food security and to a low cost/benefit ratio of agroforestry systems. The investigated agroforestry systems showed potential to restore the degraded landscape of the Atlantic Rainforest biome
Evaluation of amendments in the rehabilitation of sulfide mine tailings from São Domingos
RAMIRAN International ConferenceThe São Domingos mining area is located in the Iberian Pyrite Belt, SE Portugal, and represents a serious
environmental hazard (Matos and Martins, 2006). Exploitation dated back to pre-roman and roman times with
extraction of Ag, Au and Cu exploitation, mainly in the gossan (resulting from the ore weathering). The intense
exploitation started in the middle of 19th century, both in the gossan and sulfide ore-containing Cu, Zn, As and Pb,
and lasted until 1960, with the exhaustion of the ore (Quental et al., 2002). Different types of waste materials were
left: gossan, host rocks (volcanic with shales, and shales), roman and modern slags, smelting ashes and brittle and
blocks of pyrite (Matos, 2004; Álvarez-Valero et al., 2008). All sulfide mine wastes are typically heterogeneous and
contain high amounts of trace elements, acidic pH and small contents of organic matter and nutrients. The large
dumps containing pyrite and other metal sulfides generate, by oxidation, acidic mine drainage (AMD) which
increases the availability of trace elements for microorganisms and plants in the surrounding soils. All of these
characteristics contribute towards a system that is barely capable of supporting the establishment or survival of
plants.
The use of amendments and spontaneous colonization (vegetation) from mining areas (phytostabilization)
are cost-effective and environmentally sustainable methods to rehabilitate these contaminated and degraded areas
even in arid and semi-arid conditions (Tordoff et al., 2000; Mendez and Maier, 2008). Thus, the preparation of
Technosols from mixtures of organic and inorganic wastes can be an attractive option to rehabilitate mining areas
because they can improve physical, chemical and biological properties contributing, at the same time, towards a
strategy of wastes valorisation (Macías, 2004). The use of mixtures composed of residues with different C:N ratios
can be used to manipulate the rate of mineralization. Nevertheless, the amendments used should also promote other
soil functions (Arbestain et al., 2008). The objective of this study was to evaluate the influence of cost-effective
organic and inorganic amendments, available in the region, in the rehabilitation of sulfide materials from the São
Domingos mine are
Qualidade Físico-química E Sensorial De Genótipos De Banana
Despite the diversity of banana varieties in Brazil, only a few cultivars have the proper agronomic traits and fruit quality for commercial exploitation. This study aimed at evaluating the physicochemical traits and sensorial acceptance of banana genotypes, in order to identify those with potential for commercial growing. Six improved banana genotypes were assessed (BRS Maravilha, PC 0101, FHIA 18, TM 2803, YB 4203 and BRS Caipira), as well as three commercial cultivars (Grand Naine, Pacovan and Prata Anã). Analyses of peel and pulp color, peel thickness, pulp yield, moisture, pH, soluble solids, titratable acidity, total carotenoids and sensorial acceptance were performed. The BRS Maravilha, FHIA 18, YB 4203 and BRS Caipira genotypes presented physicochemical traits similar to the Grand Naine, Pacovan and Prata Anã commercial cultivars. The BRS Maravilha and TM 2803 genotypes had sensorial acceptance similar to the Prata Anã and Grand Naine cultivars, and are therefore promising for commercial growing, with the advantage of being resistant to the black Sigatoka and Panama disease. © 2016, Universidade Federal De Goias (UFG). All Rights Reserved.461899
MORFOGÊNESE DA PLANÍCIE ALUVIAL NA REGIÃO DA CONFLUÊNCIA ENTRE OS RIOS IVAÍ E PARANÁ E EVIDÊNCIA DE SUA PALEOCONFLUÊNCIA
O estudo apresenta a morfogênese e os estágios de evolução geomorfológica na planície e confluência dos rios Ivaí e Paraná. Informações de sensoriamento remoto, análise de fácies sedimentares e geocronologia foram utilizadas para compartimentação, e elucidam a evolução geomorfológica da planície e confluência. As analises demonstram compartimentos onde o abandono da drenagem do rio Paraná possibilitou a migração da confluência e o leito encaixado e de maior profundidade do rio Ivaí
Lead uptake capacity of Cistus plants growing in mining areas
Mining activity can give rise to large quantities of chemically unstable waste rocks and tailings which can drain potential environmentally harmful lixiviates rich in chemical elements. Plants growing in such environments can minimize chemical, physical and visual negative impacts. To evaluate lead absorption by native Cistus
growing in Braçal (NW Portugal) and São Domingos (SE Portugal) mining areas, Cistus inflatus (aerial parts) and Cistus ladanifer (leaves) were analysed by instrumental neutron activation analysis and atomic absorption spectrometric, respectively, after acid digestions. Soils were characterized by pH(H2O), organic carbon, cation exchange capacity, free Fe and Mn, total nitrogen, and assimilable K and P. Total lead was determined in soils (fraction < 2 mm) by inductively coupled plasma emission spectrometry after acid digestion, and Pb available fraction was determined by atomic absorption spectrometric and inductively coupled plasma mass spectroscopy after calcium nitrate extraction. High concentrations of total Pb are present in both mining areas soils. However, in São Domingos soils the Pb available fraction is smaller (8.3–67.3 mg kg-1) than in Braçal (276–6175 mg kg-1). Cistus inflatus aerial parts contain higher concentrations of lead (49.5–217 mg kg-1) than Cistus ladanifer leaves (40.4–48.6 mg kg-1). Both Cistus, showing no external stress signals, are well adapted to these contaminated soils with low nutrient and high Pb contents. It is apparent that these plants can be used for phytostabilization in similar mining areas
Cistus monspeliensis L. as a potential species for rehabilitation of soils with multielemental contamination under Mediterranean conditions
Conservation Biolog
Search for fingerprints of disoriented chiral condensates in cosmic ray showers
Although the generation of disoriented chiral condensates (DCCs), where the
order parameter for chiral symmetry breaking is misaligned with respect to the
vacuum direction in isospin state, is quite natural in the theory of strong
interactions, they have so far eluded experiments in accelerators and cosmic
rays. If DCCs are formed in high-energy nuclear collisions, the relevant
outcome are very large event-by-event fluctuations in the neutral-to-charged
pion fraction. In this note we search for fingerprints of DCC formation in
observables of ultra-high energy cosmic ray showers. We present simulation
results for the depth of the maximum () and number of muons on the
ground, evaluating their sensitivity to the neutral-to-charged pion fraction
asymmetry produced in the primary interaction.Comment: 7 pages, 4 figure
Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.
The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground
biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main
factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by
the altitude and position of the area relative to the sun
Disordered Boson Systems: A Perturbative Study
A hard-core disordered boson system is mapped onto a quantum spin 1/2
XY-model with transverse random fields. It is then generalized to a system of
spins with an arbitrary magnitude S and studied through a 1/S expansion. The
first order 1/S expansion corresponds to a spin-wave theory. The effect of weak
disorder is studied perturbatively within such a first order 1/S scheme. We
compute the reduction of the speed of sound and the life time of the Bloch
phonons in the regime of weak disorder. Generalizations of the present study to
the strong disordered regime are discussed.Comment: 27 pages, revte
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