197 research outputs found
Comparative Causality Analyses between Hydrological Natural Inflow and Climate Variables in Brazil
Numbers of studies have proved the significant influence of climate variables on hydrologicalseries. Considering the pivotal role of the hydroelectric power plants play in the electricity production in Brazil this paper considers the natural hydrological inflow data from 15 major
basins and 8 climate variables containing 7 El Ni˜no Southern Oscillation proxies and the sunspot numbers. The causal relationships between hydrological natural inflows and climate variables are investigated by adopting and comparing 5 different causality detection methods
(Granger Causality test, Frequency Domain Causality test, Convergent Cross Mapping, Causality test, Single Spectrum Analysis (SSA) Causality test and Periodic Autoregressive Model Causality test) that cover both well established and novel empirical approaches. Both time domain and frequency domain causality tests gain valid evidences of unidirectional
causality for a group of series; CCM achieved unidirectional causality for 18% of pairs and overwhelmingly indicated the opposite direction of causality; a mixture of results are concluded by SSA causality test; PAR based causality test obtained six unidirectional causality, but only one is really significant
Induction and growth curve of calli from leaf and nodal explants of genipap.
The aim of this study was to determine the effect of the auxin 2,4-D (2,4-dichlorophenoxyacetic) in calli formation from leaf and nodal segments of genipap and to characterize its growth curve. Explants obtained from shoots previously established from in vitro seedlings were used for calli induction. The experimental design was completely randomized in a 3x5x2 factorial with three accessions (NB, SA, SAL), five concentrations of 2,4-D (0.0; 2.0; 4.0, 6.0 or 8.0 mg L-1) and two times of measurement for calli fresh weight (30 and 60 days). There was callus formation in all treatments tested. It was observed that the best response for callus induction from leaf segments was with 2.0 mg L-1 of 2,4-D. For the nodal segment, the response among the accessions was different due to 2,4-D concentrations. The growth curve was plotted according to the fresh weight of callus obtained at intervals of 10 days up to 60 days. Through the established growth curve, the nodal-derived calli from accession SA should be transferred to a new medium, after 40 days of culture
The dust properties and physical conditions of the interstellar medium in the LMC massive star forming complex N11
We combine Spitzer and Herschel data of the star-forming region N11 in the
Large Magellanic Cloud to produce detailed maps of the dust properties in the
complex and study their variations with the ISM conditions. We also compare
APEX/LABOCA 870um observations with our model predictions in order to decompose
the 870um emission into dust and non-dust (free-free emission and CO(3-2) line)
contributions. We find that in N11, the 870um can be fully accounted for by
these 3 components. The dust surface density map of N11 is combined with HI and
CO observations to study local variations in the gas-to-dust mass ratios. Our
analysis leads to values lower than those expected from the LMC low-metallicity
as well as to a decrease of the gas-to-dust mass ratio with the dust surface
density. We explore potential hypotheses that could explain the low observed
gas-to-dust mass ratios (variations in the XCO factor, presence of CO-dark gas
or of optically thick HI or variations in the dust abundance in the dense
regions). We finally decompose the local SEDs using a Principal Component
Analysis (i.e. with no a priori assumption on the dust composition in the
complex). Our results lead to a promising decomposition of the local SEDs in
various dust components (hot, warm, cold) coherent with that expected for the
region. Further analysis on a larger sample of galaxies will follow in order to
understand how unique this decomposition is or how it evolves from one
environment to another.Comment: 24 pages, 16 figures, accepted for publication in MNRA
Análise do arranjo espacial e estrutura de focos da resinose do coqueiro nos Tabuleiros Costeiros de Sergipe.
Desenvolvimento, caracterização físico-química e sensorial de biscoito com farinha de soja orgânica de cultivares especiais para a alimentação humana.
Similaridade genética entre açaizeiros (Euterpe oleracea Mart.) procedentes de Breves, Pará, Brasil baseada em marcadores RAPD.
Caracterizou-se a similaridade genética entre açaizeiros procedentes de Breves, Pará, Brasil por meio de marcadores RAPD. Amostras de folíolos de 25 indivíduos foram coletadas para a extração de DNA genômico e aplicação 22 primers. Os produtos foram separados em eletroforese horizontal e as imagens capturadas para análise. Foram amplificadas 107 bandas polimórficas. A similaridade genética média foi de 64% e possibilitou a separação de três grupos. Logo, açaizeiros procedentes desse local, mesmo sob a ação antrópica para palmito e frutos, apresentam pouca similaridade genética
Agricultural Performance of Diverse Pastures of Complementary Species and Monoculture Pastures Defoliated According to the Leaf Regrowth Stage Window of Opportunity Criterion
In a diverse pasture of complementary species (DPCS), individual species fulfil agro-ecological functions that confer growth asynchrony and complementarity of ecosystem functions. These attributes provide yield consistency with a more even forage supply pattern across the year compared to monocultures. A common leaf regrowth stage window opportunity (LSWO) for the diverse species enables pasture defoliation that stimulates growth and persistence. The study assessed seasonal and annual growth traits of Lolium perenne (Lp), Bromus valdivianus (Bv) and Dactylis glomerata (Dg) as single grass species (Mono) sown with Trifolium repens (Tr) and as DPCS with the four species (Lp+Bv+Dg+Tr=Mix). The defoliation criteria applied (LSWO of a target species: Lp, Bv or Dg) resulted in eleven grazing events for MonoLp and MixLp, ten grazing events for MonoBv and MixBv, and nine grazing events for MonoDg and MixDg in a year. MixBv and MixDg displayed synchronized overlaps of the three species LSWOs during the seasons and across the year. MixLp had Bv and Dg being grazed slightly earlier than their LSWOs. There were no significant differences in annual herbage accumulation for all treatments. Significant differences were found within seasons, and the seasonality of the pasture growth was reduced in the DPCS when compared to their respective Mono establishment. This resulted in a more evenly distributed pasture feed resource throughout the year and can mitigate the negative impacts of extreme climatic events (longer periods of soil water restriction or saturation). The LSWO criterion enabled the successful management of monocultures and DPCS
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