Agenda Global: desarrollo en Africa

Tomando como base de datos los informes de la Comisión Económica para Africa de ONU, se ve claramente que las inversiones directas en África se han destindo mayoritariamente a sectores extractivos, especialmente del petroleo. Concentrandose en los paises productores de crudo. EL volumen de estas inversiones es mínimo comparado con el monto de la ayuda o las trasnferencias de las remesas de emigrantes. Por otra parte el mayor volumen de inversiones procede de la inversión interior bruta de los propios países. Puede decirse por tanto que el mayor esfuerzo para invertir en las economías africanas lo han realizado ellos mismos.

Baçaim e o seu território: política e economia (1534-1665)

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em História, especialidade em História dos Descobrimentos e da Expansão Portuguesa

Energia, meio ambiente e economia: o Brasil no contexto mundial

The cycle of fossil fuels as an energy source for mankind is approaching its end. Finite resources, coupled with greenhouse gas, have led to an increased effort in the search for alternative renewable energy sources. Brazil has a leading position, due to a 46% participation of renewable sources in its primary energy supply, compared to the global average of 12%. The expansion of the renewable sources in Brazil depends on medium and long term planning, and a large volume of investments. The present financial crisis will have major effects in the energy market. Despite a negative initial impact, it is expected that the rearrangement of the financial system will ultimately lead to an expansion in the use of renewable energy sources. Brazil is a tropical country, with the largest biodiversity in our planet and excellent conditions to expand the use of all forms of renewable sources.

Documentos convencionais e não convencionais em administração, ciências contábeis e economia: estudo sobre sua utilização pelos alunos de graduação

The recommended bibliographical references for the development of scientific research are those published by scientific journals. In spite of this recommendation, the use of non conventional documents by undergraduate students has been increasing. This paper, developed as a survey with 145 students of Administration, Accounting and Economics, characterizes the use these documents and analyzes teaching strategies supported in the use of non conventional documents.

Survival of conidia of sorghum ergot (caused by Claviceps africana) on panicles, seed and soil in Australia

Macroconidia of the sorghum ergot pathogen, Claviceps africana Frederickson, Mantle & de Milliano, survived in dried honeydew on soil for 13-14 weeks in a glasshouse at ambient temperatures, but for less than half that time on seed stored in a shadehouse over summer. Those on seeds stored at 4degreesC, however, survived for over a year (58-62 weeks). During summer, conidia on ergot-infected panicles buried in soil, or on the soil surface, survived for 7.5-12 weeks, whereas over winter the survival times were 4 weeks and 19-27 weeks, respectively. Macroconidia on infected panicles held above the soil surface survived for >38 weeks (8 calendar months) over winter, suggesting that they may play a role in the perennation of C. africana in Australia.

Factors influencing the germination of macroconidia and secondary conidia of Claviceps africana

The influences of temperature, time, and moisture on the germination of macroconidia and secondary conidia of Australian isolates of Claviceps africana were studied in vitro. The optimum temperature for germination of both macroconidia and secondary conidia of C. africana was 20degreesC. Although germination of macroconidia ceased near 31degreesC, approximately 30% of secondary conidia germinated at 37degreesC after 48 and 72 h of incubation. Sorghum flower extract agar stimulated macroconidium and secondary conidium germination, irrespective of temperature. Germination of macroconidia and secondary conidia on water agar started after 4 h of incubation at 20degreesC, reaching a maximum after 16-24 h and 14 h, respectively. Maximum germination of both macroconidia and secondary conidia was at greater than or equal to-5 bars at 20degreesC. Germination of secondary conidia ceased at -35 bars, whereas macroconidia germinated at water potentials as low as -55 bars at 20degreesC.

Evaluation of potential biocontrol agents against Claviceps africana in vitro and in vivo

Undiluted culture filtrates of two commercial products of Trichoderma spp., Trichopel and Trichoflow, and two isolates of Penicillium citrinum completely inhibited the conidial germination of macroconidia of Claviceps africana , the cause of ergot or sugary disease of sorghum (Sorghum bicolor) in vitro . Similarly, Pseudomonas aeruginosa and Burkholderia cepacia completely inhibited macroconidial germination, with the former being more effective at high dilutions. In contrast, these bacterial isolates failed to inhibit infection in vivo in glasshouse tests with ergot-inoculated sorghum, but all fungal biocontrol agents (including an isolate of Epicoccum nigrum) reduced the severity of disease (percentage of infected spikelets per panicle), in some cases completely inhibiting the development of ergot. In a second glasshouse trial, optimum control was achieved when the biocontrol agents were applied 3-7 days before inoculation with conidia of C. africana .

Efficacy, timing and method of application of fungicides for management of sorghum ergot caused by Claviceps africana

Trials conducted in Queensland, Australia between 1997 and 2002 demonstrated that fungicides belonging to the triazole group were the most effective in minimising the severity of infection of sorghum by Claviceps africana, the causal agent of sorghum ergot. Triadimenol ( as Bayfidan 250EC) at 0.125 kg a. i./ha was the most effective fungicide. A combination of the systemic activated resistance compound acibenzolar-S-methyl ( as Bion 50WG) at 0.05 kg a. i./ha and mancozeb ( as Penncozeb 750DF) at 1.5 kg a. i./ha has the potential to provide protection against the pathogen, should triazole-resistant isolates be detected. Timing and method of fungicide application are important. Our results suggest that the triazole fungicides have no systemic activity in sorghum panicles, necessitating the need for multiple applications from first anthesis to the end of flowering, whereas acibenzolar-S-methyl is most effective when applied 4 days before flowering. The flat fan nozzles tested in the trials provided higher levels of protection against C. africana and greater droplet deposition on panicles than the tested hollow cone nozzles. Application of triadimenol by a fixed wing aircraft was as efficacious as application through a tractor-mounted boom spray.

Ovary colonization by Claviceps africana is related to ergot resistance in male-sterile sorghum lines

Ergot, caused by Claviceps africana, has emerged as a serious threat to sorghum hybrid seed production worldwide. In the absence of gene-for-gene-based qualitative resistance in commercial cultivars, varieties with high pollen production that can escape ergot infection are preferred. Recent demonstration of differences in ergot susceptibility among male-sterile lines has indicated the presence of partial resistance. Using chitin-specific fluorescin-isothiocyanate-conjugated wheat germ agglutin and callose-specific aniline blue, this study investigated the process of sorghum ovary colonization by C. africana. Conidia germinated within 24 h after inoculation (a.i.); the pathogen was established in the ovary by 79 h a.i., and at least half of the ovary was converted into sphacelial tissue by 120 h a.i. Changes in fungal cell wall chitin content and strategic callose deposition in the host tissue were associated with penetration and invasion of the ovary. The rate of ovary colonization differed in three male-sterile lines that also differed in ergot susceptibility. This work demonstrates a possible histological basis for partial resistance in male-sterile sorghum lines that could lay the foundation for variety improvement through further breeding and selection.

Disciplina 2.1: economia brasileira

A disciplina teve como principais conte??dos: a necessidade do Estado. Externalidades e bens p??blicos. Padr??es de interven????o do Estado e as fun????es econ??micas: alocativa, distributiva e estabilizadora. Equidade e efici??ncia. O financiamento do Setor P??blico. Sistema Tribut??rio Brasileiro. Pol??tica econ??mica: fiscal, monet??ria e cambial