Cultivo de fruteiras em sistemas agroflorestais.

O que são Sistemas Agroflorestais (SAF). O novo conceito de sistemas agroflorestais. Interações entre componentes em sistemas agroflorestais. Critérios para escolha de espécies frutíferas para comporem sistemas agroflorestais. Diagnóstico de problemas de uso da terra e o desenho tecnologias agroflorestais

Weighted automata as coalgebras in categories of matrices

The evolution from non-deterministic to weighted automata represents a shift from qual- itative to quantitative methods in computer science. The trend calls for a language able to reconcile quantitative reasoning with formal logic and set theory, which have for so many years supported qualitative reasoning. Such a lingua franca should be typed, poly- morphic, diagrammatic, calculational and easy to blend with conventional notation. This paper puts forward typed linear algebra as a candidate notation for such a unifying role. This notation, which emerges from regarding matrices as morphisms of suitable categories, is put at work in describing weighted automata as coalgebras in such categories. Some attention is paid to the interface between the index-free (categorial) language of matrix algebra and the corresponding index-wise, set-theoretic notation.Fundação para a Ciência e a Tecnologia (FCT

BORAZANs: Tunable Fluorophores Based on 2-(Pyrazolyl)aniline Chelates of Diphenylboron

The reaction between 2-pyrazolyl-4-X-anilines, H(pzAnX), (X = para-OMe (L1), Me (L2), H (L3), Cl (L4), CO2Et (L5), CF3 (L6), CN (L7)) and triphenylboron in boiling toluene affords the respective, highly emissive N,N‘-boron chelate complexes, BPh2(pzAnX) (X = para-OMe (1), Me (2), H (3), Cl (4), CO2Et (5), CF3 (6), CN (7)) in high yield. The structural, electrochemical, and photophysical properties of the new boron complexes can be fine-tuned by varying the electron-withdrawing or -donating power of the para-aniline substituent (delineated by the substituent\u27s Hammett parameter). Those complexes with electron-withdrawing para-aniline substituents such as CO2Et (5), CF3 (6), and CN (7) have more planar chelate rings, more ‘quinoidal\u27 disortion in the aniline rings, greater chemical stability, higher oxidation potentials, and more intense (φF = 0.81 for 7 in toluene), higher-energy (blue) fluorescent emission compared to those with electron-donating substituents. Thus, for 1 the oxidation potential is 0.53 V versus Ag/AgCl (compared to 1.12 V for 7), and the emission is tuned to the yellow-green but at an expense in terms of lower quantum yields (φF = 0.07 for 1 in toluene) and increased chemical reactivity. Density functional calculations (B3LYP/6-31G*) on PM3 energy-minimized structures of the ligands and boron complexes reproduced experimentally observed data and trends and provided further insight into the nature of the electronic transitions

Development of bioplastics from agro-wastes

During centuries synthetic polymers have been used in a variety of applications in the everyday of human life. They became essential due to its versatility, durability and low cost [1]. However, due to their excessive use, several drawbacks as its resistance to the decomposition, toxicity after incineration and accumulation in the environment induce negative ecological impact in landfills and water contamination [2]. Moreover, plastics production implies the use of non-renewable resources, such as, oil and natural gas that represents about 8 % of global consumption [1,2]. Therefore, become crucial to search for new ecological materials toward innovative and cost-effective fabrication of environmentally degradable plastics demonstrating similar performance to conventional ones [1,3]. Simultaneously, the high amount of agro-wastes generated from food industry have been a growing concern, around 1.3 billion tons are leftover, which became an environmental and financial issue [1]. Among these agro-waste stands out, food waste, halum and stems of vegetables/fruits, grains and seeds, from which it is possible to obtain natural polymers [3]. Biopolymers exhibit unique properties and can be produced from plants and crops wastes. Rubber, proteins, starch and cellulose are some of the examples [4]. Cellulose has been used for the production of biopolymers, nevertheless, because of the difficulty inherent in its extraction process, various methods have been studied in order to optimize this process. Currently, cellulose derivatives are used, which is an example of cellulose acetate, whose chemical purification process is quite costly and lengthy [1]. Thus, the present work, aims to directly synthetize biopolymers from agro-wastes. Green chemistry methodology is applied to extract natural polymers, such as cellulose, from vegetable wastes. Structural, morphological and mechanical characterization of the produced materials are accessed and compared with conventional synthetic polymers. Also, biodegradability assays will be performed to check the microorganisms’ capability to assimilate the produced bioplastics

Soil phosphorus properties and management for perennial crops in the central Amazon.

Predominant soils in the Brazilian Amazon. Phosphorus constraints to continuous soil use in the Brazilian Amazon. Phosphorus fertilization to perennial crops in the central Amazon. Phosphorus budgets in perennial crop plantations

Analysis of the deep chlorophyll maximum across the Azores Front

Physical, chemical and biological observations made in late July and August 1997 across the Azores Front (37ºN, 32ºW to 32ºN, 29ºW) are presented. The objectives of the study were: (1) to analyse horizontal and vertical profiles of temperature, salinity, density, nutrients and chlorophyll-a (Chl a) of the top 350 m; (2) to identify the main differences in the deep Chl a Maximum (DCM) and hydrographic structure between the water masses that pass north and south of the Azores Front; and (3) to estimate phytoplankton primary production in these water masses. Horizontal and vertical profiles of salinity, temperature, density, nutrients and phytoplankton pigments in the top 350 m were analysed. The Front separates two distinct water types: the 18 ºC ModeWater (18MW) of subtropical origin, and the 15 ºC ModeWater (15MW) of sub-polar origin. Differences in the DCM and hydrographic structure between 18 MW and 15 MW were observed in the contour plots of each section. The average Chl a concentration between 5 and 200 m depth decreased significantly from 15 MW to 18 MW. The same pattern was observed for the Chl a concentration at the DCM depth. A vertical one-dimensional model was used to estimate the phytoplankton primary production in the 15 MW and 18 MW and led to an estimated water column average gross primary productivity (GPP) between 1.08 and 2.71 mg C

Microstrucure and thermal features a-Si:H and nc-Si:H thin films produced by r.f. sputtering

Amorphous and nanocrystalline silicon thin films have been produced by reactive r.f. sputtering and their microstructure, optical and thermal properties were evaluated. A good correlation was found between the microstructure determined by Raman spectroscopy and X-ray diffraction and the thermal transport parametersFCT Project POCTI / CTM / 39395 / 200