Maritime safety administration in Guinea

The aims of this paper are to describe the actual Maritime Safety Administration in the Republic of Guinea as it presently exists and its evolution in the process of development so as to indicate where such development may be needed. This system of development will lead to the establishment of the Guinean shipping industry and to the establishment of an efficient Maritime Safety Administration. As the present Guinean Maritime Shipping legislation needs to be revised and amended in order to execute this assignment, the National Maritime Safety Administration is greatly in need of its own qualified staff who will put Guinea in the coming few years at the international level

Genetic variation and host-parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding

The parasitic weeds Striga asiatica and Striga hermonthica cause devastating yield losses to upland rice in Africa. Little is known about genetic variation in host resistance and tolerance across rice genotypes, in relation to virulence differences across Striga species and ecotypes. Diverse rice genotypes were phenotyped for the above traits in S. asiatica- (Tanzania) and S. hermonthica-infested fields (Kenya and Uganda) and under controlled conditions. New rice genotypes with either ecotype-specific or broad-spectrum resistance were identified. Resistance identified in the field was confirmed under controlled conditions, providing evidence that resistance was largely genetically determined. Striga-resistant genotypes contributed to yield security under Striga-infested conditions, although grain yield was also determined by the genotype-specific yield potential and tolerance. Tolerance, the physiological mechanism mitigating Striga effects on host growth and physiology, was unrelated to resistance, implying that any combination of high, medium or low levels of these traits can be found across rice genotypes. Striga virulence varies across species and ecotypes. The extent of Striga-induced host damage results from the interaction between parasite virulence and genetically determined levels of host-plant resistance and tolerance. These novel findings support the need for predictive breeding strategies based on knowledge of host resistance and parasite virulence

Fertilisers differentially affect facultative and obligate parasitic weeds of rice and only occasionally improve yields in infested fields

Different fertilisers were field tested to investigate whether they (1) suppress the obligate parasitic weed Striga asiatica and the facultative parasitic weed Rhamphicarpa fistulosa, and (2) favour rainfed rice yields under parasitic weed infestation. Four years of experiments were conducted in southwest Tanzania, in a S. asiatica-infested rainfed upland and a R. fistulosa-infested rainfed lowland field. Treatments included sole mineral (NPK or Di-Ammonium Phosphate —DAP— plus urea), organic (cattle manure or rice husk), combinations of mineral and organic fertilisers and a no-fertiliser control. Fertilisers moderately suppressed the obligate parasite S. asiatica, but no correlations between infestation level and soil fertility status were observed. In the lowland field, fertilisers promoted the facultative R. fistulosa, in particular the ones that included organic components. Plant-available phosphorus, exchangeable potassium and soil organic matter content correlated with R. fistulosa infestation levels. Positive fertiliser effects on yields were found in both parasitic weed infested fields, except in years with high S. asiatica infestation levels. Rice husks alone and rice husks or manure combined with DAP and urea increased yields and soil fertility most. We conclude that fertilisation differentially affects the obligate and facultative parasitic weeds of rice systems; obligate parasites may be slightly suppressed, but facultative parasites may even be stimulated. Meanwhile, consistent rice yield increases under parasitic weed infested conditions cannot be obtained with fertiliser application when parasitic weed infestation levels are too high

Systems approaches to innovation in pest management: reflections and lessons learned from an integrated research program on parasitic weeds in rice

This paper provides a retrospective look at a systems-oriented research program, on the increasing occurrence of parasitic weeds in rainfed rice in sub-Saharan Africa, to qualitatively assess merits and identify challenges of such approach. We gained a broad contextual overview of the problem and different stakeholders' roles, which enabled identification of entry points for innovations in parasitic weed management. At the crop level parasitic weed infestation is associated with poor soil fertility and water management. Farmers' infrequent use of inputs to control them was caused by various factors, ranging from fears of undesired side effects (agronomic) to a lack of quality control of products (institutional). Furthermore, there may be enough extension agents, but they lack the required training on (parasitic) weed management to provide farmers with advice, while their organizations do not provide them with the necessary means for farm visits. At even higher organizational levels we observed a lack of coherent policies on parasitic weed control and implementation of them. Merits and challenges of an integrated multi-stakeholder and multi-level research project are discussed

Do NERICA rice cultivars express resistance to Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze under field conditions?

The parasitic weeds Striga asiatica and Striga hermonthica cause high yield losses in rain-fed upland rice in Africa. Two resistance classes (pre- and post-attachment) and several resistant genotypes have been identified among NERICA (New Rice for Africa) cultivars under laboratory conditions (in vitro) previously. However, little is known about expression of this resistance under field conditions. Here we investigated (1) whether resistance exhibited under controlled conditions would express under representative Striga-infested field conditions, and (2) whether NERICA cultivars would achieve relatively good grain yields under Striga-infested conditions. Twenty-five rice cultivars, including all 18 upland NERICA cultivars, were screened in S. asiatica-infested (in Tanzania) and S. hermonthica-infested (in Kenya) fields during two seasons. Additionally, a selection of cultivars was tested in vitro, in mini-rhizotron systems. For the first time, resistance observed under controlled conditions was confirmed in the field for NERICA-2, -5, -10 and -17 (against S. asiatica) and NERICA-1 to -5, -10, -12, -13 and -17 (against S. hermonthica). Despite high Striga-infestation levels, yields of around 1.8 t ha−1 were obtained with NERICA-1, -9 and -10 (in the S. asiatica-infested field) and around 1.4 t ha−1 with NERICA-3, -4, -8, -12 and -13 (in the S. hermonthica-infested field). In addition, potential levels of tolerance were identified in vitro, in NERICA-1, -17 and -9 (S. asiatica) and in NERICA-1, -17 and -10 (S. hermonthica). These findings are highly relevant to rice agronomists and breeders and molecular geneticists working on Striga resistance. In addition, cultivars combining broad-spectrum resistance with good grain yields in Striga-infested fields can be recommended to rice farmers in Striga-prone areas

Peoples’ attitude toward COVID-19 vaccine, acceptance, and social trust among African and Middle East countries

Background: To end the COVID-19 pandemic, a large part of the world must be immune to the virus by vaccination. Therefore, this study aimed to gauge intent to be vaccinated against COVID-19 among ordinary people and to identify attitudes towards vaccines and barriers for vaccine acceptance. Methods: The study population comprises 1880 people residing in different countries that answer a prepared questionnaire. The questionnaire topics are demographics, historical issues, participants’ attitudes and beliefs regarding vaccines, concerns, and vaccine hesitancy. Results: Attitudes and beliefs relating to vaccines in general, and the COVID-19 vaccine, were ascertained. Overall, 66.81% of the contributors would like to be vaccinated against COVID-19, while %33.19 did not intend to be vaccinated. Reasons for COVID-19 vaccine hesitancy included concern regarding vaccine side effects, fear of getting sick from the uptake of the vaccine, and the absence of accurate vaccine promotion news. Individuals with higher education believe that India (68.6%) produces the best vaccine (P<0.001), while healthcare workers think the Chinese vaccine (44.2%) is the best (P=0.020). Individuals with higher education have not been vaccinated, not be healthcare workers, and females were the most contributors to effective of the vaccine in reducing mortality from COVID-19 disease. Conclusion: Given the degree of hesitancy against COVID-19 vaccination, a multifaceted approach to facilitate vaccine uptake that includes vaccine education, behavioral change strategies, and health promotion, is paramount

Understanding resistance in inter-specific rice cultivars to the parasitic witchweed Striga

The root hemi-parasitic witchweeds Striga hermonthica and S. asiatica are considered the most important biotic constraint to cereal crop production in sub-Saharan Africa (SSA). These parasites infect the staple cereal crops (rice, maize, sorghum and millet) resulting in considerable yield losses. Control of these parasites is very difficult as the Striga seed bank is widespread and damage to the crop occurs long before the parasite emerges above ground. Resistant cultivars are considered to be an effective and affordable component of an integrated Striga management strategy but very few are available to farmers as sources of resistance to Striga are relatively scarce and little is known about the molecular genetic basis of resistance to this parasite. Rice is an economically important cereal crop in SSA that is mostly cultivated by resource-poor farmers. Both cultivated rice species, Oryza sativa (L.) and Oryza glaberrima (Steud.), are grown in Africa. To take advantage of superior traits from each species, AfricaRice Center and partners developed inter-specific rice cultivars called NERICA (NEw RICe for Africa) for rain-fed upland ecosystems. Because of their high yields, even on low nutrient soils where Striga spp. are prevalent, the NERICA cultivars have been widely adopted by farmers. Despite this, very little is known about their resistance to different species and ecotypes of Striga. The aims of this study are to determine how resistant and/or tolerant the upland NERICA cultivars are to different species and ecotypes of Striga under controlled environment and Striga-infested field conditions, to identify whether resistance is broad spectrum or specific to particular ecotypes of Striga and to characterize the phenotype of the resistance at a histological level. Finally using a Chromosome Segment Substitution Line (CSSL) population derived from a cross between an O. glaberrima cultivar MG12 (donor parent) and an O. sativa cultivar Caiapo (recurrent parent), the genetic basis of post-attachment resistance to Striga is investigated. The NERICA rice cultivars showed different susceptibilities to both S. hermonthica and S. asiatica species under controlled environment conditions. Some cultivars showed good broad-spectrum resistance against several Striga ecotypes and species whilst others showed intermediate resistance or were very susceptible. In addition, some cultivars showed resistance to a particular ecotype of Striga but were susceptible to others. The phenotype of a resistant interaction was often characterized by necrosis at the host parasite interface and an inability of the parasite to penetrate the host root endodermis. In general, the most resistant NERICA cultivars grew better than the very susceptible cultivars although even a small number of parasites caused a reduction in above ground host biomass. There was however, genetic variation for tolerance to Striga (the ability to grow and yield well in the presence of Striga) amongst the NERICA cultivars. The NERICA cultivars were also grown in field trials at Kyela in Tanzania (under S. asiatica infestation) and at Mbita Point in Kenya (under S. hermonthica infestation) in 2010 and 2011 to determine the impact of environment on the expression of resistance. The resistance of the NERICA cultivars against S. hermonthica and S. asiatica, in the field, was broadly similar to that observed in the laboratory although there were some exceptions. These results allow us to recommend particular cultivars for Striga-infested regions but they also illustrate the necessity of understanding the genetic basis of resistance to different ecotypes of Striga for breeding of durable resistance (and pyramiding of appropriate resistance genes) in host cultivars adapted to different rice agro-ecosystems in sub-Saharan Africa. Sixty four lines of an inter-specific CSSL population and the parent cultivars MG12 and Caiapo were phenotyped for resistance to S. hermonthica. MG12 showed good resistance to S. hermonthica whilst Caiapo was very susceptible. The CSSLs showed a range of susceptibility to the parasite, however, only two CSSLs showed the same strong resistance phenotype as MG12. Graphical genotyping and a Quantitative Trait Loci (QTL) analysis revealed a large QTL on chromosome 12 (designated STR12.1) which explained at least 80 % of the variation for resistance in the population and suggests that resistance to S. hermonthica (in MG12) is due to one (or a few genes) of major effect. This finding opens the way for the identification of candidate Striga resistance genes (through fine mapping approaches) and their transfer to farmer-preferred cultivars via marker assisted breeding

Problèmes actuels de prise en charge des principales urgences médico-chirurgicales en République du Mali

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Rice yields under Rhamphicarpa fistulosa-infested field conditions, and variety selection criteria for resistance and tolerance

The facultative parasitic weed Rhamphicarpa fistulosa, is a widespread problem in rain-fed rice production systems in Africa. Little is known about rice varietal differences in infection level and yields in fields infested by this root hemi-parasite. During three cropping seasons (2012–2014), an experiment was conducted to address these knowledge gaps and to identify suitable variety selection criteria for R. fistulosa resistance and tolerance. Sixty-four adapted lowland rice varieties, including all interspecific lowland varieties of NERICAs, their most common parents – IR64 and TOG5681 – and two locally popular varieties – Mwangulu and Supa India – were grown in an R. fistulosa-infested field in southern Tanzania. As expected from a facultative parasite, host plant varieties had no effect on R. fistulosa numbers. Consistent varietal differences in R. fistulosa biomass were however observed, with no Year × Variety effects, and this parameter can therefore be used to select for resistance. Parasite-free observation plots were established in the last year. Due to the facultative nature of the parasite, creating such R. fistulosa-free plots was simply obtained by regular early weeding. The presence of parasite-free control plots enabled assessment of worthwhile additional information such as parasite-free yield, parasite-inflicted yield losses (RYLR) and varietal differences in tolerance. Under R. fistulosa-infested conditions (3-season averages, no Year × Variety interaction effect), rice grain yields ranged from 1.2 t ha−1 for the worst performing variety (TOG5681) to 2.4 t ha−1 for the best performing varieties (NERICA-L-39, -20). Under R. fistulosa-free conditions (2014 only) rice grain yields ranged from 2.4 (NERICA-L-22) to 5.4 t ha−1 (NERICA-L-17). Tolerant varieties were characterized by a low RYLR and a high parasite biomass (e.g. Supa India, NERICA-L-20). The selection measures identified are effective, easy and practical under field conditions. They facilitated identification of thirteen varieties with high resistance, sixteen varieties with low RYLR and two varieties with high tolerance. These varieties would be invaluable for future rice breeding programs. For farmers in R. fistulosa-endemic areas the most promising varieties are probably NERICA-L-40 and -31, as they combine good yields under infested conditions with low levels of parasite infection