Effect of repeated dosing of Delta 9-Tetrahydrocannabinol, the major psychoactive ingredient of marijuana, on memory in mice

Purpose: Marijuana is the most widely used illicit drug in the United States. However, marijuana and cannabinoid derivatives have potential therapeutic uses. Studies in cannabis users have yielded contradictory results with regard to long-term effects on cognitive functions. There is no prospective study assessing this issue, and such studies may raise ethical issues in humans, whereas mice have been shown to exhibit similar cannabinoid-mediated behaviors as humans. The purpose of this study was to assess the consequences of chronic administration of Δ9-THC, the major psychoactive component of marijuana, in a mouse memory model. Methods: In Experiment 1, the dose-response relationship of Δ9-THC was assessed in the object recognition task, a well-documented rodent memory model. In Experiment 2, mice were treated repeatedly with either escalating doses of Δ9-THC or vehicle for one week, and then challenged with the drug to assess whether tolerance had developed. Results: Acute Δ9-THC dose-dependently interfered with memory as assessed in the object recognition task (ED50 95% C.I. = 0.5 (0.1 to1.7) mg/kg). No tolerance to the memory disruptive effects of 1 mg/kg Δ9-THC was evident after chronic treatment. Conclusions: Considerably low doses of Δ9-THC impaired memory. The failure of chronic Δ9-THC to produce tolerance in this model was surprising considering that a similar dosing regimen has been reported to produce tolerance in non-mnemonic behaviors. The results suggest that memory is particularly sensitive to the disruptive effects of Δ9-THC and chronic cannabis use is likely to elicit persistent impairment of cognitive function. Caution should be applied in advocating chronic use of medicinal cannabinoids. Potential solutions lie in reinforcing education on the harm caused by cannabis use and availability of alternative solution to cannabis users, especially among youth that have shown to be more vulnerable to this drug

Analyse juridique des crises humanitaires dues aux inondations dans l'Arrondissement de Douala 5ème, Cameroun

Le Cameroun fait partie des pays concernés par des crises humanitaires aggravées parfois par le risque d’inondation. Ces crises entrainent des déplacements des personnes qui vivent des situations de violation des droits les plus élémentaires. Si pour les protéger, le Cameroun élabore des lois et adhère aux textes juridiques, un écart entre textes et réalité s’observe cependant. En effet, le cadre légal existant, à la fois muet et lacunaire n’offre pas de protection adéquate. L’étude juridique des crises humanitaires dues aux inondations dans la commune de Douala 5ème vise à contribuer à l’étude du droit applicable face à la gestion du risque d’inondation. Menée dans une approche à la fois herméneutique et prospective, appuyée par les approches documentaire et qualitative, l’étude révèle que la gestion des catastrophes est beaucoup plus réactive que proactive. Elle omet en effet les rôles préventif et protecteur que joue le droit dans la mise en place des textes de lois portant sur les domaines dont l’importance et la maîtrise contribuent à la réduction du risque d‘inondation. D’autre part, l’approche cartographie réglementaire montre que certains quartiers connaissent de fortes inondations et requièrent une réglementation rigoureuse quant à leur occupation. Enfin, l’étude met en évidence des obstacles tels que le poids de la tradition, l’inefficacité des cadres institutionnels etc., qui associés à l’absence des données sur les PDI (personnes déplacées internes) et la problématique de coexistence des acteurs freinent toute action humanitaire. De son côté, la population, ultime victime des inondations, n’est souvent pas associée dans le choix des politiques et des mesures prises pour la gestion du risque d’inondation. Il ressort en outre de l’étude que le respect et la prise en compte des droits de la personne humaine à travers chacune des phases de gestion du risque d’inondation constituent des éléments en souffrance. L’adoption de lois sur ce risque, la sensibilisation de la population sur les mécanismes de prévention et de gestion sont quelques-unes des recommandations qui, à notre sens doivent recevoir un caractère contraignant pour leur mise en œuvre.13. Climate actio

LES DETERMINANTS DE LA STRUCTURE FINANCIERE DES SOCIETES A PARTICIPATION PUBLIQUE BURUNDAISES

The present study aims to identify the main determinants of the financial structure of 15 Burundian companies with public participation under the supervision of SCEP, a public agency monitoring public enterprises. An econometric analysis with a panel data from 2010 to 2017 was performed. The results, based on econometric model estimates, indicate that four of the six variables examined can be considered as major determinants of the financial structure of the companies involved in this study. They include State shareholding, company age, level of liquidity and profitability. State shareholding has a positive effect, but the other three variables have negative effects. While the effects of these three variables with negative effects confirm ‘POT’ predictions, State shareholding is accounted by the ‘TOT’. This implies that even though the relative importance of the ‘POT’ is underscored, theoretical frameworks of reference complement one another, which accounts for the choice of the financial structure of the companies studied

Profitability of diammonium phosphate use in bush and climbing bean-maize rotations in smallholder farms of Central Burundi

Article purchasedSoil fertility decline is a major constraint to bean (Phaseolus vulgaris L.) and maize (Zea mays) production in the Central Highlands of Burundi. Nutrient sources, specifically fertilizers, are paramount to increasing the production in the regions. Hence, improving fertilizer use efficiency is considered as a key factor towards sustainable intensification. The use of grain legumes with low harvest indices, such as climbing beans, are assumed to improve soil fertility and fertilizer use efficiency. This study compares the rotational effects of bush and climbing bean varieties on maize and evaluates the profitability of diammonium phosphate (DAP, 18–46-0) fertilizer in the bean-maize rotations in 59 smallholder farms of Mutaho district, Gitega Province in Central Burundi. The application of DAP fertilizer significantly increased the grain yields by 14% and 21% for bush and climbing beans, respectively (P 2 $$−1) in a climbing bean-maize rotation while 45% of the farmers in a bush bean-maize rotation. Regression tree analysis showed that targeting fertilizer use to soils with higher C and clay content, and ensuring timely planting are the predominant factors to ensure fertilizer response and profitable returns. This study confirms the need for integrated soil fertility management (ISFM), and that a combination of judicious fertilizer use, an improved grain legume (climbing bean) and adjustment to local conditions (targeting to responsive soils) maximizes economic returns of legume-cereal rotation systems

Bean utilization and commercialization in great lakes region of Central Africa: the case of smallholder farmers in Burundi

This paper evaluates production and commercialization constraints that prevent smallholder farmers from effectively utilizing beans with regard to household food and income security. The study was conducted in six provinces of Burundi in 2010 using a multi-stage stratified sampling procedure to select a sample of 380 smallholder bean farmers. Linear regression models were used to estimate factors influencing the quantity of beans marketed by smallholder farmers. Different ways in which beans are utilized include household consumption, selling, gifts and as seeds. Both improved and local seeds are used, with over 65% of farmers in Muyinga planting local varieties. Results showed that highly educated farmers were more likely to increase commercialization by 10%. However storage of beans for food was more likely to reduce commercialization by 23% while those who gave out beans as gifts had a higher (12%) chance of commercialization. Transport losses were likely to reduce commercialization by 15%, but knowledge of bean networks and access to information from traders was likely to increase bean commercialization by about 10%. Emphasis on interventions (information and extension services) that increase farm level productivity and market led approaches between potential buyers of beans and rural communities will help to reduce poverty and address food insecurity in rural areas

Aflatoxin contamination of maize and groundnut in Burundi: distribution of contamination, identification of causal agents and potential biocontrol genotypes of Aspergillus flavus

Open Access JournalAflatoxin contamination of the staples maize and groundnut is a concern for health and economic impacts across sub-Saharan Africa. The current study (i) determined aflatoxin levels in maize and groundnut collected at harvest in Burundi, (ii) characterized populations of Aspergillus section Flavi associated with the two crops, and (iii) assessed aflatoxin-producing potentials among the recovered fungi. A total of 120 groundnut and 380 maize samples were collected at harvest from eight and 16 provinces, respectively. Most of the groundnut (93%) and maize (87%) contained aflatoxin below the European Union threshold, 4 μg/kg. Morphological characterization of the recovered Aspergillus section Flavi fungi revealed that the L-morphotype of A. flavus was the predominant species. Aflatoxin production potentials of the L-morphotype isolates were evaluated in maize fermentations. Some isolates produced over 137,000 μg/kg aflatoxin B 1 . Thus, despite the relatively low aflatoxin levels at harvest, the association of both crops with highly toxigenic fungi poses significant risk of post-harvest aflatoxin contamination and suggests measures to mitigate aflatoxin contamination in Burundi should be developed. Over 55% of the L-morphotype A. flavus did not produce aflatoxins. These atoxigenic L-morphotype fungi were characterized using molecular markers. Several atoxigenic genotypes were detected across the country and could be used as biocontrol agents. The results from the current study hold promise for developing aflatoxin management strategies centered on biocontrol for use in Burundi to reduce aflatoxin contamination throughout the value chain

Stress Hormones Receptors in the Amygdala Mediate the Effects of Stress on the Consolidation, but Not the Retrieval, of a Non Aversive Spatial Task

This study examined the effects of the arousal level of the rat and exposure to a behavioral stressor on acquisition, consolidation and retrieval of a non-aversive hippocampal-dependent learning paradigm, the object location task. Learning was tested under two arousal conditions: no previous habituation to the experimental context (high novelty stress/arousal level) or extensive prior habituation (reduced novelty stress/arousal level). Results indicated that in the habituated rats, exposure to an out-of-context stressor (i.e, elevated platform stress) impaired consolidation and retrieval, but not acquisition, of the task. Non-habituated animals under both stressed and control conditions did not show retention of the task. In habituated rats, RU-486 (10 ng/side), a glucocorticoid receptor (GR) antagonist, or propranolol (0.75 µg/side), a beta-adrenergic antagonist, injected into the basolateral amygdala (BLA), prevented the impairing effects of the stressor on consolidation, but not on retrieval. The CB1/CB2 receptor agonist WIN55,212-2 (WIN, 5 µg/side) microinjected into the BLA did not prevent the effects of stress on either consolidation or retrieval. Taken together the results suggest that: (i) GR and β-adrenergic receptors in the BLA mediate the impairing effects of stress on the consolidation, but not the retrieval, of a neutral, non-aversive hippocampal-dependent task, (ii) the impairing effects of stress on hippocampal consolidation and retrieval are mediated by different neural mechanisms (i.e., different neurotransmitters or different brain areas), and (iii) the effects of stress on memory depend on the interaction between several main factors such as the stage of memory processing under investigation, the animal's level of arousal and the nature of the task (neutral or aversive)

Integrated soil fertility management for bean-maize based farming systems in Gitega Province, Burundi: Understanding and enhancing the agronomic and economic benefits of organic and mineral inputs

Securing sustainable food security remains a huge challenge in sub-Saharan Africa. Yet, there is an urgent need to do so as the region faces high population density, continuous cultivation of already depleted soils, limited availability of resources to farmers all of it leading to low crop productivity. In this region, soil acidity and low N and P supply capacities are common problems over large areas of agricultural land. These problems are aggravated by the lack of improved and resilient germplasm of the major crops, including maize, and various legume species. Hence, it provides the ideal testing ground to evaluate the Integrated Soil Fertility Management (ISFM) paradigm with its different options, thereby proving the conceptual 'staircase' of improving yield effects and profitability of fertilizer use. The current research is conducted in three action sites (Buraza, Makebuko and Mutaho districts) of the Consortium for Improving Agriculture-based Livelihoods in Central Africa (CIALCA) in Gitega Province. Diammonium phosphate (DAP, 18-46-0) was used to remediate soil N and P deficiencies but its use is limited in rural areas because of its poor availability, its wrong application rates, high cost, lack of store rooms and good roads. Hence the region needs to find strategies that would enhance yield increments with concomitant increased agricultural net returns. The general objective of this work was to validate the ISFM concept on bean-maize based farming systems in Gitega Province, Central Burundi; thereby proving the underlying hypothesis of stepwise maximization of the profitability of DAP fertilizer use. First, we carried out a field survey to evaluate the local farmers' knowledge on DAP fertilizer use and assess DAP effects on bean and maize production in two districts of Gitega Province: Buraza and Makebuko. We found a huge variability in plot sizes, plant densities, mineral DAP fertilizer rates on beans and maize production. This illustrates how farmers have different attitudes and this should be taken into account as a precondition for the establishment of profitable and sustainable nutrient management systems. Profitability of DAP use on local germoplasm under local farmers' practices was also assessed. Only 3 % and 40 % of farmers' fields provided profitable net returns for beans and maize, respectively. These results justify the need for ISFM. Secondly, we assessed the applicability of the Compositional Nutrient Diagnosis (CND) approach under smallholder farming practices, and the frequency of nutrient deficiencies for maize cropping in Buraza and Makebuko districts of Central Highlands of Burundi in the short rains of 2012 (2012SR). The trials were carried out on 76 fields for Buraza and 66 fields for Makebuko districts, hence totalling 142 fields covered in this study. In each field, two plots were demarcated to accommodate two treatments, a control without fertilizer and a treatment with 1kg of DAP fertilizer. Composite soil samples and maize ear leaves were collected from all plots and shipped to the International Center for Tropical Agriculture (CIAT) in Nairobi for analysis. Indophenol blue method was used for N-analysis and ICP-OES for the determination of other nutrients. A total of 284 samples was used in the CND computations. The maize simplex comprises eight nutrients N, P, K, Ca, Mg, S, Mn and Zn and the filling value R9 which takes care of all other nutrients not included in this analysis. The occurrence of nutrient deficiencies showed that 1 kg of DAP resulted in alleviating some of them, especially in Buraza district. However, N and P remained the main limiting ones for maize productivity in both control and fertilized plots in Makebuko district. The persistent P-deficiency may be due to the strongly acid, P-fixing soils. Zn and Mn-deficiencies occurred mostly in both control and fertilized plots of Buraza district. Zn and Mn-deficiencies are expected to limit yields. We observed in this study that actually in Buraza district, the DAP fertilizer induced a smaller yield increase on average (29 %) compared to the one in Makebuko district (46 %) where these two nutrients are not limiting. Next, we assessed the profitability of DAP fertilizer use on local and improved varieties of climbing bean (LR 2012) and maize (SR 2013) in smallholder farms of Buraza district in Gitega province in Central Burundi. Local varieties used were AMAKUTSA and ISEGA for bean and maize while G13607 and ZM 605-24C were improved varieties for climbing bean and maize. Fertilizer and variety effects were significantly larger when planted on time in a soil with larger total N (TN > 1.5 g kg-1) and total C (TC > 16 g kg-1) contents for beans while characterized by a moderate soil clay content (38 - 40 %) with high total C (TC ≥ 19 g kg-1) content for maize. Large fertilizer and improved variety effects consequently resulted in large value cost ratios (VCR). For improved climbing beans, VCR values on average were 4.49 $$-1 which is more than the average of 3.19 $$-1 obtained from local climbing beans. The same trend was also observed for maize, where the value cost ratio for the improved maize on average, was almost twice the one of local maize. The use of DAP fertilizer (100 kg ha-1) for the improved climbing bean and maize varieties resulted in larger grain yields, larger net benefits, larger value cost ratios and larger marginal rates of return than for local climbing bean and maize varieties. Finally, we tested the application of DAP fertilizer with improved bush and climbing bean varieties, in rotation with a subsequent improved maize variety. Rotational effects of a bush and climbing bean variety were compared, and the profitability of DAP fertilizer assessed in bean-maize rotations in 59 smallholder farms of Mutaho district, Gitega Province in Central Burundi in 2 cropping seasons: LR 2012 for beans and SR 2013 for maize. The improved varieties used were MLB 122-94B and G13607 for bush and climbing beans and ZM 605-24C for maize, respectively. The use of DAP fertilizer (50 kg ha-1) increased on average grain yields up to 1000 kg ha-1 for bush beans and 1800 kg ha-1 for climbing beans, respectively. Application of DAP fertilizer to the two bean varieties resulted in large yield differences when beans were planted on time in soils with a total C below 2.5 %. Such response was expected since the initial soil analysis indicated that the soils in which beans were cropped, were of low fertility, acidic, with small amounts of total N, total C and available P. The positive effect of DAP on maize grain yields was realized for about 60 % of the farmers. With the use of the same nutrients, maize following climbing beans out yielded maize following bush beans for about 48 % of the farmers. Large fertilizer and bean variety effects consequently resulted in a large value cost ratio. For climbing beans, VCR values on average were 4.25 $$-1 , more than double the average of 1.83 $$-1 obtained from bush beans. The same trend was also observed for maize planted after beans, where the control maize plots on average yielded 4000 kg ha-1. The value cost ratio was on average two times larger when maize followed climbing beans than when it followed the bush beans. Such profitability was realized when maize grain yields ranged between 1067 and 4622 kg ha-1. These yields were obtained from fields with high total C (TC > 23 g kg-1), low total N (TN < 2 g kg-1) and high clay content (more than 37 % clay). Results from this study revealed that an improved climbing bean preceding an improved maize on soils enriched with DAP fertilizer is a promising alternative to the local smallholder farmers' practices. In summary, the study confirmed the insufficient knowledge of smallholder farmers on how to use fertilizer according to their local conditions, which consequently leads to soil nutrient mining. There is a dire need for more trainings and awareness creativity emphasizing the use of fertilizer at their best advantage and development of site specific fertilizer recommendations instead of blanket. We noted that the use of fertilizer to the improved varieties was more profitable than for local varieties. In this way of implementing ISFM, we also found that use of fertilizer on climbing bean-maize rotation generated more rotational effects and was more profitable than that of bush bean-maize rotation. We therefore concluded that use of site specific fertilizer recommendations and high yielding improved grain legume varieties would be the most important factors to consider in initiatives to improve agronomic and economic productivity of legume-cereal rotations in such depleted soils.status: publishe