59 research outputs found
An Evaluation of the Operational Restrictions Imposed to Congonhas Airport by IAC 121-1013
The objective of this study is to propose a review of the operational restrictions imposed on Congonhas airport by IAC 121-1013, seeking a balance between flight safety and operational efficiency.
The researchers calculated the landing performance (using specific software), taking into account particular aircraft system failures that increase landing distance. The results indicated that the measures imposed by the IAC have little or no effect on the operational safety increase. Additionally, the restrictions created operational complexity for the airport and reduced its efficiency by impacting airline costs. At the end of the study, the researchers suggest a reissue of the IAC based on the data presented
Determination of biological and physicochemical parameters of <i>Artemia franciscana</i> strains in hypersaline environments for aquaculture in the Colombian Caribbean
Background: Artemia (Crustacea, Anostraca), also known as brine shrimp, are typical inhabitants of extreme environments. These hypersaline environments vary considerably in their physicochemical composition, and even their climatic conditions and elevation. Several thalassohaline (marine) environments along the Colombian Caribbean coast were surveyed in order to contribute to the knowledge of brine shrimp biotopes in South America by determining some vital biological and physicochemical parameters for Artemia survival. Additionally, cyst quality tests, biometrical and essential fatty acids analysis were performed to evaluate the economic viability of some of these strains for the aquaculture industry.Results: In addition to the three locations (Galerazamba, Manaure, and Pozos Colorados) reported in the literature three decades ago in the Colombian Caribbean, six new locations were registered (Salina Cero, Kangaru, Tayrona, BahĂa Hondita, Warrego and Pusheo). All habitats sampled showed that chloride was the prevailing anion, as expected, because of their thalassohaline origin. There were significant differences in cyst diameter grouping strains in the following manner according to this parameter: 1) San Francisco Bay (SFB-Control, USA), 2) Galerazamba and Tayrona, 3) KangarĂș, 4) Manaure, and 5) Salina Cero and Pozos Colorados. Chorion thickness values were smaller in Tayrona, followed by Salina Cero, Galerazamba, Manaure, SFB, KangarĂș and Pozos Colorados. There were significant differences in naupliar size, grouping strains as follows(smallest to largest): 1) Galerazamba, 2) Manaure, 3) SFB, KangarĂș, and Salina Cero, 4) Pozos Colorados, and 5) Tayrona. Overall, cyst quality analysis conducted on samples from Manaure, Galerazamba, and Salina Cero revealed that all sites exhibited a relatively high number of cysts.g-1. Essential fatty acids (EFA) analysis performed on nauplii from cyst samples from Manaure, Galerazamba, Salina Cero and Tayrona revealed that cysts from all sites exhibited high arachidonic acid:20:4(n-6) (ArA) and eicosapentaenoic acid: 20:5(n-3) (EPA) levels comparable to the control sample (SFB). In contrast, most cysts collected (including SFB) at different locations, and during different months, presented low docosahexaenoic acid: 22:6(n-3) (DHA) levels (Manaure was the only exception with high DHA levels). Some variations in EPA and ArA levels were observed in all sites, contrasting with the much lower DHA levels which remained constant for all locations, except for Manaure which exhibited variable DHA levels. DHA/EPA ratio was overall very low for all sites compared to SFB cysts. All strains had a low DHA/ArA, but a high EPA/ArA ratio, including the control.Conclusion: The Colombian A. franciscana habitats analyzed were determined to be thalassohaline, and suitable for A. franciscana development. EFA profiles demonstrated that Tayrona, Galerazamba, Manaure and Salina Cero strains are suitable food for marine fish and crustacean culture because of their high EPA/ArA ratio, but might have to be fortified with DHA rich emulsions depending on the nutritional requirements of the species to be cultured, because of their overall low DHA content. The relatively small nauplii are appropriate for marine larvaeculture. In contrast, the strains from Tayrona, KangarĂș, Salina Cero, and Pozos Colorados may be of use but limited to Artemia small biomass production quantities, because of the small surface area of their respective locations; Artemia could be exploited at these locations for local aquaculture applications. In general, cyst quality evaluation for Manaure, Salina Cero and Galerazamba cysts revealed that cysts from these three locations could improve their quality by concentrating efforts on cyst processing techniques. Finally, most locations had great A. franciscana production potential and require different degrees of water quality and/or infrastructure management
A concentração de fĂłsforo na tolerĂąncia de cultivares de trigo Ă toxicidade de alumĂnio em soluçÔes nutritivas
Extraction methods and availability of micronutrients for wheat under a no-till system with a surface application of lime
Resposta ao calcĂĄrio e ao fĂłsforo de genĂłtipos de trigo com diferentes tolerĂąncias ao alumĂnio
Avaliação fĂsica e quĂmica e aceitação pelo consumidor de laranjas 'ValĂȘncia', produzidas sob sistemas de cultivo orgĂąnico e convencional
Atributos quĂmicos e produção de milho em um latossolo vermelho eutrofĂ©rrico tratado com lodo de esgoto
CaracterĂsticas quĂmicas do lixiviado na fase de enraizamento de estacas de cacau em substratos adubados com fĂłsforo
Avaliação do uso de fertilizantes organominerais e quĂmicos na fertirrigação do cafeeiro irrigado por gotejamento
InfluĂȘncia do EPTC no desenvolvimento e absorção de macronutrientes pela cultura de feijĂŁo (Phaseolus vulgaris L. var. Carioca)
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