17 research outputs found

    Species diversity and distribution of ruderal flora on landfills in Maradi city, Niger

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    Waste management continues to be a critical environmental issue in cities. It impacts on the well being of the population, the environment and the biodiversity. In the city of Maradi, in Niger, more interest is given to the problem in order to understand the whole waste management system. It is in this context that this study is carried out to investigate on the role of ruderal flora on the municipal solid wastes dumpsites and landfill sites in Maradi city. The specific objectives are to determine the floristic diversity and distribution of ruderal flora on the municipal solid waste disposal sites, and to identify potential species that can play an important role in the phytoremediation of these sites. In total, 65 species belonging to 52 genera and 24 families were recorded. These species can be categorised into two groups containing anthropic and nitrophilic species according to the ascending Hierarchical Classification (AHC) at 25% similarity. Characteristic species of the first group G1 are Amaranthus viridis and Cucurbita pepo, and Datura innoxia and Cucumis melo for the second group G2. Other ruderal species, namely Amaranthus spinosus L., Amaranthus viridis L., Celosia trygina L., Datura innoxia Mill., and an introduced woody species, Cuphea hyssopifolia Kunth., found are not included in the Maradi city list of species. Datura innoxia, Amaranthus viridis and Amaranthus spinosus are species known to tolerate different degrees of pollution and their ecology should be further study to better understand how they can be used for phytoremediation on this kind of sites

    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

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    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    25th annual computational neuroscience meeting: CNS-2016

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    The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

    Effets de la modernisation de tannerie sur l’impact de ses activités sur la qualité des eaux : cas de la tannerie de Maradi au Niger

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    peer reviewedThe modernization of the tannery of Maradi had intervened in 2009 with the introduction of the process of tanning in the chromium. We estimated the influence of this change of operating process through an evaluation of the impact characteristics evolution of the solid and liquid discharges of this tannery on water. It stands out that the modernization of the tannery activities had more or less significant effects on these environment elements. We noted a relative improvement of the quality of underground waters illustrated by the regression of the content in chloride and nitrates rates stabilization. While the content in chromium evolved in a significant way as well as the pH. However, all the four above parameters remain below WHO standards. By cons, this modernization has almost not influenced the impact on the quality of surface waters. The values of BOD and COD have continued to rise despite the installation of a treatment system. Thus this surface water, including the pond, proved to be a major public health risk for domestic and agricultural use and is also a source of air pollution.La modernisation de la tannerie de Maradi était intervenue en 2009 avec l’introduction du procédé de tannage au chrome. Nous avons évalué l’influence de ce changement de mode opératoire à travers une évaluation de l’évolution des caractéristiques de l’impact des rejets solides et liquides de cette tannerie sur l’eau. Il ressort de celle-ci que la modernisation des activités de la tannerie a eue des effets plus ou moins significatifs sur ces éléments de l’environnement. C’est ainsi que on a noté une relative amélioration de la qualité des eaux souterraines illustrée par la régression de la teneur en chlorure, une stabilisation des taux des nitrates. Cependant, la teneur en chrome a évolué de façon significative de même que le pH. Toutefois, tous les quatre paramètres précités restent en dessous des normes OMS. Par contre, elle n’a quasiment pas influencé l’impact sur la qualité des eaux de surface. Les valeurs de la DBO et la DCO ont continué de monter malgré l’installation d’un système d’épuration. C’est ainsi que cette eau de surface, notamment la mare, s’est avérée être un risque majeur de santé publique pour une utilisation domestique et agricole et constitue également une source de pollution de l’air

    Farmers perception and adaptation strategies to climate change in the oasis system of Goure (Southeast Niger)

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    Les savoirs liés au temps et à l’espace, et l’identification des stratégies paysannes pour affronter les problèmes climatiques sont indispensables pour toute compréhension des questions climatiques. Pour mieux apprécier les perceptions de la variabilité climatique et les stratégies d’adaptation utilisées, une enquête semi structurée qui a concerné 60 personnes réparties dans 4 villages du département de Gouré, situé dans l’Est du Niger, est conduite selon une approche qualitative et quantitative. Les effets de la variabilité climatique ressentis par les agriculteurs sont l’aridité du climat, l’augmentation de la température et le caractère aléatoire des pluies. Les éleveurs la perçoivent de façon indirecte à travers la réduction du fourrage et de la disponibilité d’eau. Ces effets ont poussé ces populations à adopter des stratégies d’adaptation comme la recherche de nouvelles variétés à cycle court et supportant les poches de sécheresse, la pratique des techniques de fixation des dunes pour la restauration du couvert herbacé, l’utilisation de la fumure organique, la modification des dates de semis, le stockage de fourrage, le déstockage des animaux pendant la soudure, les prières collectives de demande de pluies. Elles sont toutefois insuffisantes du fait de la persistance des effets négatifs de la variabilité climatique au Niger.Knowledge related to the perception of time and space, and identification of farmers’ strategies for dealing with climate change is a perequisite for a good understanding of climate issues. Farmers’ climate variability perceptions and adaptation strategies was studied using a survey conducted with sixty (60) farmers in the department of Gouré, located in eastern Niger. Results showed that farmers directly experience changes in climate variability through temperature increase, frequent drought and erratic rainfall. By contrast, herders sense the effects of climate change indirectly through fodder reduction and scarce water availability. These effects have prompted farmers to adopt coping strategies such as the use of improved varieties, early and drought tolerant, sand dune stabilization and land reclamation, use of organic manure, changing of planting dates, storage of fodder, the destocking of animals during drought periods, collective prayers for rain. These strategies, however, appear to be insufficient for addressing the negative effects of climate change in this part of Niger
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