2,908 research outputs found
Effect of fermented, hardened, and dehulled of chickpea (Cicer arietinum) meals in digestibility and antinutrients in diets for tilapia (Oreochromis niloticus)
Among the most typical feed sources for tilapia, plants represent a low-cost source in substituting for traditional high-cost feed ingredients. Fermentation, hardening and dehulling are common grains processing techniques to make plant nutrients available and more digestible to fish. Apparent digestibility coefficients (ADC) of dry matter and protein, and antinutrients (phytic acid and tannins) in fermented, hardened and dehulled chickpea (Cicer arietinum) meals were determined for juvenile Nile tilapia (Oreochromis niloticus). The highest ADC was obtained with processed (fermented, hardened and dehulled) chickpea meals compared with non-processed. Results indicated that fermentation increased the protein content by 13.1%, decreased the content of ash and phytic acid (47.5 and 45%, respectively), and increased the ingredient apparent digestibility of dry matter (ADM) by 23.2%, and the ingredient apparent digestibility of protein (ADP) by 41.9%. Dehulling meal increased the protein (5.7%) and lipid (6.4%) content of chickpea grains; decreased fiber, ash and tannin content (75.3%, 19.1%, and 84.5%, respectively); and increased ADM by 12.8%, and ADP by 10.4%. We conclude that fermented, hardened and dehulled chickpea meals represent a potential alternative in diets for juvenile O. niloticus
Ontologies in a Multi-Agent System for Automated Scheduling
Multi-Agent Systems (MAS) have been successfully used in a wide range of applications such as robotics and e-commerce, and in particular in planning and scheduling. The aim of this paper is to present the interesting features that the use of ontologies in MAS offers. As an example, the development of a MAS for automated planning and scheduling in a University Research Group Scenario is shown in this paper. In this scenario, researchers are frequently proposed to attend internal meetings about several subjects such as lessons planning or research evaluations. Scheduling and negotiating meeting details such as time and location becomes highly complicated as the number of intended attendees increases. Moreover, there are usually conflicts about the use of some common resources such as portable computers or projectors. As can be seen, the scheduling problem that the MAS solves is very easy. So having solved it is not what is important about this paper. In contrast, what is important is the potential which a scheduler can schedule for the items whose description, for example, is on the web, and can read on it (without knowing a~priori) the logic of how the scheduling can be done
Kinetics and Mechanism of β-Brass Dealloying in Aqueous 0.5 M Sodium Chloride Solution Derived from Combined Scanning Tunneling Microscopy and Electrochemical Data
Scanning tunneling microscopy (STM) combined with conventional electrochemical techniques was used to determine the kinetics and mechanism of β-brass dealloying in aqueous neutral solutions containing NaCl. In the potential range where selective dissolution of Zn occurs, electrochemical data suggest that the corrosion process is controlled by surface diffusion of Cu atoms. STM imaging of β-brass after dealloying shows the development of an irregular surface which attains a stationary regime. The irregular surface topography consists of faceted islands with atomically smooth terraces. For a constant dealloying time, the extent of faceting increases as the potential is moved positively, and at a constant applied potential it increases with electrodissolution time. The proportionality ξ ∝ Lα was established, where ξ is the interface width related to L, the sample size. The exponent R is related to the degree of surface disorder. The value of R derived from STM is in the range 0.7 ≤ α ≤ 0.8, i.e. close to the predictions of aggregation models including surface diffusion.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
Purification and properties of the very high density lipoprotein from the hemolymph of adult Triatoma infestans
The very high density lipoprotein (VHDL) of Triatoma injesfum hemolymph from adult males has been isolated and purified by two-step density gradient ultracentrifugation. It appears to be homogeneous as judged by native polyacrylamide gel electrophoresis. The content of VHDL in hemolymph was estimated to be 8 mg proteidml. The purified protein has a molecular weight (M,) of 450,000, is composed of six subunits of M, p 77,000, and possesses a high content of aromatic amino acids. This protein is glycosylated and contains 3% of lipids by weight with a remarkable amount of free fatty acids (25% of total lipids). The I: injesfans VHDL has a different lipid and amino acid composition from lipophorin. The lipid composition and the spectroscopic studies using cis-parinaric acid indicated a high fatty acid binding affinity. It has nine binding sites per mol of VHDL. Competence studies revealed that VHDL has its highest affinity for the binding of palmitic acid followed by stearic and arachidonic acids.Instituto de Investigaciones Bioquímicas de La Plat
8000 years of environmental evolution of barrier–lagoon systems emplaced in coastal embayments (NW Iberia)
The rocky and indented coast of NW Iberia is characterized by the presence of highly valuable and vulnerable, small and shallow barrier– lagoon systems structurally controlled. The case study was selected to analyse barrier–lagoon evolution based on detailed sedimentary architecture, chronology, geochemical and biological proxies. The main objective is to test the hypothesis of structural control and the significance at regional scale of any highenergy event recorded. This work is also aimed at identifying general patterns and conceptualizing the formation and evolution of this type of coastal systems. The results allowed us to establish a conceptual model of Holocene evolution that applies to rock-bounded barrier–lagoon systems. The initial stage (early Holocene) is characterized by freshwater peat sedimentation and ended by marine flooding. The timing of the marine flooding depends on the relation between the elevation of the basin and the relative mean sea-level position; the lower the topography, the earlier the marine inundation. Thus, the age of basin inundation ranged from 8 to 4 ka BP supporting significant structural differences. Once marine inundation occurred, all systems followed similar evolutionary patterns characterized by a phase of landward barrier migration and aeolian sedimentation towards the back-barrier (i.e. retrogradation) that extended circa 3.5 ka BP. The later phases of evolution are characterized by a general trend to the stabilization of the barriers and the infilling of the lagoons. This stabilization may be temporally interrupted by episodes of enhanced storminess or sediment scarcity. In this regard, washover deposits identified within the sedimentary architecture of the case study explored here suggest pervasive high-energy events coeval with some of the cooling events identified in the North Atlantic during the mid- to late Holocene
8000 years of environmental evolution of barrier–lagoon systems emplaced in coastal embayments (NW Iberia)
The rocky and indented coast of NW Iberia is characterized by the presence of highly valuable and vulnerable, small and shallow barrier– lagoon systems structurally controlled. The case study was selected to analyse barrier–lagoon evolution based on detailed sedimentary architecture, chronology, geochemical and biological proxies. The main objective is to test the hypothesis of structural control and the significance at regional scale of any highenergy event recorded. This work is also aimed at identifying general patterns and conceptualizing the formation and evolution of this type of coastal systems. The results allowed us to establish a conceptual model of Holocene evolution that applies to rock-bounded barrier–lagoon systems. The initial stage (early Holocene) is characterized by freshwater peat sedimentation and ended by marine flooding. The timing of the marine flooding depends on the relation between the elevation of the basin and the relative mean sea-level position; the lower the topography, the earlier the marine inundation. Thus, the age of basin inundation ranged from 8 to 4 ka BP supporting significant structural differences. Once marine inundation occurred, all systems followed similar evolutionary patterns characterized by a phase of landward barrier migration and aeolian sedimentation towards the back-barrier (i.e. retrogradation) that extended circa 3.5 ka BP. The later phases of evolution are characterized by a general trend to the stabilization of the barriers and the infilling of the lagoons. This stabilization may be temporally interrupted by episodes of enhanced storminess or sediment scarcity. In this regard, washover deposits identified within the sedimentary architecture of the case study explored here suggest pervasive high-energy events coeval with some of the cooling events identified in the North Atlantic during the mid- to late Holocene
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