Importância dos fatores bióticos (pragas e doenças) em pré-colheita na qualidade e conservação da castanha

A castanha em fresco é um fruto de elevada qualidade, mas facilmente perecível. A qualidade é influenciada por fatores bióticos e abióticos que ocorrem em pré-colheita, durante a colheita e em pós-colheita. As podridões das castanhas associadas a fungos podem desenvolver-se durante o crescimento dos frutos ainda na árvore, quando da queda dos ouriços na altura da colheita ou por contaminação durante o armazenamento. As podridões associadas a Penicillium spp., Aspergillus spp., Fusarium spp., Phoma. castanea, Acrospeira mirabilis e S. pseudotuberosa são frequentes em condições de conservação e provocam prejuízos muito elevados. Pretende-se, com este trabalho, avaliar os fatores pré-colheita que afetam a produção e a qualidade final da castanha. Para concretizar o estudo selecionaram-se 5 soutos na região de Bragança, tendo-se recolhido castanhas em 3 períodos diferentes, durante o período de colheita. Será avaliado o estado sanitário das castanhas em diferentes tempos de conservação (imediatamente após a colheita, um mês após a colheita e dois meses após a colheita, com as castanhas armazenadas em camara de frio (frigorifico) a 12ºC. As castanhas são avaliadas quanto á presença de pragas (Bichado-da-castanha ou Gorgulho-da-castanha) e verificado a presença de fungos. Nas castanhas com podridões observaram-se as características morfológicas dos sintomas e procede-se ao isolamento do fungo em meio de cultura PDA (Potato Dextrose Agar, 39 gr/L). A identificação das espécies será realizada por observação morfológica dos isolados e por técnicas moleculares por amplificação e sequenciação da região ITS do ADN ribossomal (ADNr) utilizando os iniciadores universais ITS1 e ITS4.The fresh chestnut is a fruit of high quality, but easily perishable. Quality is influenced by biotic and abiotic factors that occur in pre-harvest, during harvest and post-harvest. Chestnut nut rots associated with fungi may develop during the growth of the fruits still in the tree, during the fall of the burrs at harvest time or through contamination during storage. The rot associated with Penicillium spp., Aspergillus spp., Fusarium spp., P. castanea, Acrospeira mirabilis and S. pseudotuberosa are frequent in that conservation conditions and cause very high losses. This work intends to evaluate the pre-harvest factors that affect the final production and quality of the nuts. In order to complete the study, 5 chestnut trees were selected in the region of Bragança, and chestnuts nuts were collected in 3 different periods during the harvest period. The health status of the nuts will be evaluated at different storage times (immediately after harvest, one month after harvest and two months after harvest), when the chestnuts nuts are stored in an incubator at 12° C. The chestnuts are evaluated for the presence of pests (chestnut beetle or brown weevil) and presence of fungi were observed outside and into the kernel. In the nuts with rotting, the morphological characteristics of the symptoms were observed and the fungus was isolated in PDA culture medium (Potato Dextrose Agar, 39 gr/L). Identification of species will be performed by morphologic microscopic observations and molecular techniques by amplification and sequencing of the ITS region of ribosomal DNA (rDNA) using the universal primers ITS1 and ITS4

Experimental investigation of the thermal performance of a parabolic dish concentrating solar collector

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Thermal performance of a point focus concentrating solar collector comprising a 2000 mm diameter, and a focal length of 665 mm symmetric parabolic dish concentrator covered with reflective aluminum tiles of 0.9 reflectivity and SiC honeycomb volumetric absorber, which use atmospheric air as heat transfer fluid is experimentally investigated. The absorber was tested for two different mass flow rates. This is an attempt to assess the potential of this collector as a component of solar cooker with heat storage, a prototype that has a potential to enable indirect and off-sun cooking. The prototype of a solar cooker under investigation is intended to be used in rural areas (in Mozambique) to satisfy the multiple domestic needs in thermal energy as part of a global effort to mitigate the consequences of one of the severe problems the world face today (desertification and deforestation), some of which are attributed to climate change. Thermal efficiency of the collector was estimated for the two mass flow rates. Preliminary results show that at the target temperature range the collector efficiency remained above 70 % and that the higher the mass flow rate, the lower the temperature of the air leaving the collector.dc201

A solar energy resources assessment in Mozambique

Just as with other Southern African Development Community (SADC) countries, Mozambique faces severe, interrelated problems of energy and environment linked, with massive consumption of fuel wood biomass. The conventional power grid provides less than 7% of the energy needs for the country’s 17 million inhabitants, and about 83% of the energy consumed in the country comes from biomass. Renewable energy resources can play an important role in the process of development of the country. From the vast renewable energy resources available in the country, solar energy represents one of those with the highest potential. Thus, the evaluation of the potential of solar energy systems in small-scale applications suitable for villages is a strategically good starting point for promotion of sustainable rural development. One of the major impediments in carrying out such studies is the fact that the exact behaviour of solar energy resources throughout the country has not been well studied. In this paper a general characterisation of the global, diffuse and direct solar radiation fields in Mozambique is presented. The study is based on experimental data measured by the National Institute of Meteorology (INAM) in the period 1970- 2000. For these analyses global, diffuse and direct solar radiation data from three stations along the coast line and three stations in the interior of the country have been used. The six stations were representative of the three main regions of the country, namely south, centre and north. Furthermore, sunshine hours data of one selected station was analysed

Impact of Community-Based Larviciding on the Prevalence of Malaria Infection in Dar es Salaam, Tanzania.

The use of larval source management is not prioritized by contemporary malaria control programs in sub-Saharan Africa despite historical success. Larviciding, in particular, could be effective in urban areas where transmission is focal and accessibility to Anopheles breeding habitats is generally easier than in rural settings. The objective of this study is to assess the effectiveness of a community-based microbial larviciding intervention to reduce the prevalence of malaria infection in Dar es Salaam, United Republic of Tanzania. Larviciding was implemented in 3 out of 15 targeted wards of Dar es Salaam in 2006 after two years of baseline data collection. This intervention was subsequently scaled up to 9 wards a year later, and to all 15 targeted wards in 2008. Continuous randomized cluster sampling of malaria prevalence and socio-demographic characteristics was carried out during 6 survey rounds (2004-2008), which included both cross-sectional and longitudinal data (N = 64,537). Bayesian random effects logistic regression models were used to quantify the effect of the intervention on malaria prevalence at the individual level. Effect size estimates suggest a significant protective effect of the larviciding intervention. After adjustment for confounders, the odds of individuals living in areas treated with larviciding being infected with malaria were 21% lower (Odds Ratio = 0.79; 95% Credible Intervals: 0.66-0.93) than those who lived in areas not treated. The larviciding intervention was most effective during dry seasons and had synergistic effects with other protective measures such as use of insecticide-treated bed nets and house proofing (i.e., complete ceiling or window screens). A large-scale community-based larviciding intervention significantly reduced the prevalence of malaria infection in urban Dar es Salaam

Insecticide resistance and the future of malaria control in Zambia.

BACKGROUND: In line with the Global trend to improve malaria control efforts a major campaign of insecticide treated net distribution was initiated in 1999 and indoor residual spraying with DDT or pyrethroids was reintroduced in 2000 in Zambia. In 2006, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of these activities and the potential impact of emerging insecticide resistance on disease transmission. METHODS: Mosquitoes were captured daily through a series of 108 window exit traps located at 18 sentinel sites. Specimens were identified to species and analyzed for sporozoites. Adult Anopheles mosquitoes were collected resting indoors and larva collected in breeding sites were reared to F1 and F0 generations in the lab and tested for insecticide resistance following the standard WHO susceptibility assay protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 14 years. RESULTS: A total of 619 Anopheles gambiae s.l. and 228 Anopheles funestus s.l. were captured from window exit traps throughout the period, of which 203 were An. gambiae malaria vectors and 14 An. funestus s.s.. In 2010 resistance to DDT and the pyrethroids deltamethrin, lambda-cyhalothrin and permethrin was detected in both An. gambiae s.s. and An. funestus s.s.. No sporozoites were detected in either species. Prevalence of P. falciparum in the sentinel sites remained below 10% throughout the study period. CONCLUSION: Both An. gambiae s.s. and An. funestus s.s. were controlled effectively with the ITN and IRS programme in Zambia, maintaining a reduced disease transmission and burden. However, the discovery of DDT and pyrethroid resistance in the country threatens the sustainability of the vector control programme

Antibody responses to the RTS,S/AS01E vaccine and plasmodium falciparum antigens after a booster dose within the phase 3 trial in Mozambique

Study of immune correlates against malaria after vaccination with RTS,S/ASO1E: a comphrensive immunological arm of a Phase III double-blind, randomize, controlled multi-centre trial (MAL067).Dades primàries associades a l'article publicat a NPJ Vaccines, vol. 5 [https://doi.org/10.1038/s41541-020-0192-7]The RTS,S/AS01E vaccine has shown consistent but partial vaccine efficacy in a pediatric phase 3 26 clinical trial using a 3-dose immunization schedule. A fourth dose 18 months after the primary 27 vaccination was shown to restore the waning efficacy. However, only total IgG against the 28 immunodominant malaria vaccine epitope has been analyzed following the booster. To better 29 characterize the magnitude, nature and longevity of the immune response to the booster, we 30 measured levels of total IgM, IgG and IgG1-4 subclasses against three constructs of the 31 circumsporozoite protein (CSP) and the hepatitis B surface antigen (HBsAg, also present in RTS,S) 32 by quantitative suspension array technology in 50 subjects in the phase 3 trial in Manhiça, 33 Mozambique. To explore the impact of vaccination on naturally acquired immune responses, we 34 measured antibodies to P. falciparum antigens not included in RTS,S. We found increased IgG, 35 IgG1, IgG3 and IgG4, but not IgG2 nor IgM, levels against vaccine antigens one month after the 4th 36 dose. Overall, antibody responses to the booster dose were lower than the initial peak 37 response to primary immunization and children had higher IgG and IgG1 levels than infants. 38 Higher anti-Rh5 IgG and IgG1-4 levels were detected after the booster dose, suggesting that RTS,S 39 partial protection could increase some blood stage antibody responses. Our work shows that the 40 response to the RTS,S/AS01E booster dose is different from the primary vaccine immune 41 response and highlights the dynamic changes in subclass antibody patterns upon the vaccine 42 booster and with acquisition of adaptive immunity to malaria

High Level of Pyrethroid Resistance in an Anopheles funestus Population of the Chokwe District in Mozambique

Background Although Anopheles funestus is difficult to rear, it is crucial to analyse field populations of this malaria vector in order to successfully characterise mechanisms of insecticide resistance observed in this species in Africa. In this study we carried out a large-scale field collection and rearing of An. funestus from Mozambique in order to analyse its susceptibility status to insecticides and to broadly characterise the main resistance mechanisms involved in natural populations. Methodology/Principal Findings 3,000 F1 adults were obtained through larval rearing. WHO susceptibility assays indicated a very high resistance to pyrethroids with no mortality recorded after 1h30min exposure and less than 50% mortality at 3h30min. Resistance to the carbamate, bendiocarb was also noted, with 70% mortality after 1h exposure. In contrast, no DDT resistance was observed, indicating that no kdr-type resistance was involved. The sequencing of the acetylcholinesterase gene indicated the absence of the G119S and F455W mutations associated with carbamate and organophosphate resistance. This could explain the absence of malathion resistance in this population. Both biochemical assays and quantitative PCR implicated up-regulated P450 genes in pyrethroid resistance, with GSTs playing a secondary role. The carbamate resistance observed in this population is probably conferred by the observed altered AChE with esterases also involved. Conclusion/Significance The high level of pyrethroid resistance in this population despite the cessation of pyrethroid use for IRS in 1999 is a serious concern for resistance management strategies such as rotational use of insecticides. As DDT has now been re-introduced for IRS, susceptibility to DDT needs to be closely monitored to prevent the appearance and spread of resistance to this insecticide