Effet des insecticides, des variétés de chou et des dates de semis sur Plutella xylostella (L.) (Lepidoptera : Plutellidae) dans les hautes terres de l’Ouest Cameroun

Le but de ce travail a été d’étudier l’effet des insecticides, des variétés de chou et des dates de semis sur la teigne du chou à Dschang. Bacillus thuringiensis a été pulvérisé sur le chou pour contrôler les insectes. Deux insecticides conventionnels (Cyperdim 220 EC et Cypercal 100 EC) ont été utilisés comme produits comparatifs. Les variétés chou, Green Coronet et Marché de Copenhague ont été testées. Le dispositif expérimental a été en blocs aléatoires complets avec quatre répétitions. Le comptage direct des insectes a été fait hebdomadairement jusqu’à deux semaines avant la récolte. L’abondance des insectes, les dégâts, les rendements et les pertes ont été évalués. Les dégâts moyens et les pertes moyennes en 2008 ont été moins importants avec Biobit que Cyperdim et Cypercal. Le nombre de teigne en 2008 (247,5) a été plus important qu’en 2009 (2,6). Green Coronet a hébergé plus de teigne (182,6) que Marché de Copenhague (67,5). Mais son rendement moyen (96,58 t/ha) a été significativement plus élevé que celui de Marché de Copenhague (67,15 t/ha). Biobit a été efficace comme insecticide. Green Coronet est tolérante. Son usage peut être combiné avec l’application de Biobit en période de forte infestation de la teigne à Dschang.Mots clés: Chou, Biobit, teigne du chou, lutte intégrée, Cypercal 100EC, Cyperdim 220EC

New Venture Creation and Infrastructure in Developed and Developing World Countries

Knowledge of contexts under which infrastructure affects entrepreneurship is often used as important policy tool to inform and improve infrastructural investments, and to boost entrepreneurial activities in developed and developing world countries (DDWC). Research has shown that scholars do not give infrastructure due importance in entrepreneurship studies. This thesis aims to critically evaluate nature and type of the relationships between infrastructure and new venture creation in DDWC in order to achieve the following objectives: i) Further understanding, and develop extant knowledge about infrastructure; its definition, its classification and its importance. ii) Highlight different infrastructure categories as a possible explanation to regional variations in the levels of entrepreneurial activities across DDWC. iii) Demonstrate how to construct an index of the economic infrastructure category and apply it to rank some countries. iv) Evaluate direct and/or indirect effect(s) of dimensions of the economic infrastructure category (aggregated and disaggregated) on some country-level entrepreneurial activities (e.g. entrepreneurial transition, necessity entrepreneurship etc.) in DDWC. First, a systematic literature review (SLR) was undertaken and its findings used to define, then classify infrastructure into four categories, and nature/type of its reported relationships with new venture creation explored. Effects were largely positive and direct for economic and institutional categories, mixed for the social category, and unknown for the technological category. Next, economic infrastructure (EI) index constructed from several secondary data sources (World Bank, IMF, GEM etc.) was used to rank 112 developing world countries. Subsequently, index effect was evaluated on nascent entrepreneurial transition on sample of 42 sub-countries. Ordinary Least Squares (OLS) and Two Stage Least Squares (2SLS) regression techniques were applied, and index was shown to affect said transition only indirectly, through corruption perceptions. Index effect (disaggregate) was also evaluated on motivation-driven entrepreneurship. OLS and hierarchical multiple regression (HMR) techniques were applied on sample of 31 developed world countries. Findings suggested index attributes that enhanced opportunity-motivated entrepreneurship (OME) rather hurt necessity-motivated entrepreneurship (NME), and vice versa. Furthermore, state fragility was shown to mediate associations between some index attributes and OME, as well as NME. Keywords: infrastructure, new venture creation, developed and developing world, entrepreneurial transition, corruption perception, opportunity-motivated and necessity-motivated entrepreneurship, state fragility

Apolipoprotein gene variants and susceptibility to essential hypertension in Cameroon

Background: Essential hypertension (EH) is determined by both genetic and environmental factors and their complex interactions. Apolipoprotein (Apo) ɛ gene polymorphisms have been reported to be at the basis of EH in some ethnic groups but not in others. This inconsistency suggests that the association of Apo ɛ gene polymorphism could be dependent on the ethnic group. Cameroon  is comprised of three ethnic groups and such studies have never been carried out in any of these groups despite a prevalence of 47.35% in the Cameroonian community.Objective: To investigate the relationship between Apo ɛ gene polymorphisms and EH in the Bantu ethnic group of Cameroon.Design: Cross sectional study.Setting: Bantu ethnic group of South West Cameroon.Results: Whereas advanced age, SBP, DBP, lack of exercise and family history constituted risk factors of EH, sex, body mass index (BMI), Fasting blood sugar  (FBS), lipid profile, smoking, excessive alcohol consumption did not. Following  conduction of association studies between Apo ɛ gene variants and risk factors of EH, statistical analyses of genotype and allele frequencies revealed that the  frequency of ɛ4 allele was statistically higher in the hypertensive than the  normotensive group.Conclusion: The ɛ4 allele predisposes Cameroonians of the Bantu ethnic group to EH

Utilisation des données géologiques et gestion des informations multi-sources pour l’analyse de l’aléa glissement de terrain/éboulement dans le secteur Nord-Ouest de la région de Yaoundé

Le secteur Nord-Ouest de la région de Yaoundé au relief accidenté est sensible aux glissements de terrain et aux éboulements. Les témoins de manifestations anciennes outrepassent les délimitations connues des zones à risque ; d’où la complexité de la configuration de l’aléa. En synchronisant les données géomorphologiques et géologiques telles que la topographie, la morphologie des versants, les éléments structuraux de la tectonique cassante, les variétés de sols et de la roche mère, il a été établi une carte thématique plus élaborée et plus rapprochée de la réalité du terrain. Elle révèle au-dessus de 800 m, des zones à « aléa fort » et à « aléa très fort », suite à l’existence de falaises, de pentes abrupts et de matériaux fragilisés. En-dessous de 800 m elle révèle des zones à « aléa assez fort » suite à l’existence de couronnes discontinues d’édifices présentant des ruptures de pente et des matériaux fragilisés.Mots-clés : glissement de terrain, éboulement, topographie, données géologiques, morphologie des versants, roche mère, région de Yaoundé

Insertion/deletion gene variants of angiotensin converting enzyme do not predispose cameroonians of the Bantu ethnic group to essential hypertension

The insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene has been reported to be implicated in the predisposition to essential hypertension (EH). This association may depend on ethnic and genetic backgrounds. The objective of this study was to determine if the possible I/D polymorphism in the Bantu ethnic group of Cameroon is associated with EH. Data were analyzed from 60 patients and 50 healthy controls in order to access the risk factors of EH in this ethnic group. Comparison of gene and allele frequency distributions between the two populations revealed that systolic and diastolic blood pressures, age, family history and lack of physical exercise were risk factors of EH in this ethnic group. Comparison of means of age, systolic and diastolic blood pressures as well as the proportions of individuals with a family history of EH and lack of physical exercise were higher in the hypertensive than the normotensive group (p < 0.05). In addition, Comparison of genotype and allele frequencies between the two populations did not reveal statistically significant differences (p > 0.05). Moreover, analyses of relationship between ACE I/D gene variants and EH did not reveal any association (p > 0.05). Consistently, the two groups also did not present with differences in I and D allele distribution (p > 0.05). These results suggest that EH is not associated with ACE I/D polymorphism.© 2016 International Formulae Group. All rights reserved.Keywords: ACE, Gene polymorphism, SWR, Cameroo

Positive association of ace i/d gene variants with genetic predisposition to diabetes in the Bantu ethnic group of Cameroon

Background: Pre-disposition to diabetes is possibly associated with gene polymorphismsof the renin–angiotensin system (RAS). Angiotensin-converting enzyme (ACE) geneis one of the genes of the RAS system whose polymorphisms have been suggested tobe risk factors for type 2 diabetes melitus (T2DM). The involvement of the ACE genepolymorphism in diabetes show inconsistent results across ethnic groups as revealedby earlier studies.Objective: To investigate the association between insertion/deletion (I/D) polymorphismof the 287 bp DNA fragment in intron 16 of the ACE gene and genetic pre-dispositionto T2DM.Design: Case–control studySetting: Bantu ethnic group of South West CameroonSubject: Diabetic subjects (n= 50) and non-diabetic subjects (n=50) of both sexes agedbetween 31 and 73 years.Results: The distribution of three geno-types (II, ID, and DD) was significantly differentbetween the diabetic and non-diabetic groups (χ2 = 10.3, p = 0.001). Also, frequency ofD allele was higher in the diabetic patients than in the non-diabetic subjects (p= 0.03).Conclusion: Our data suggest that the D allele of ACE gene polymorphism is associatedwith the genetic pre-disposition to develop T2DM

The effects of extract of Azadirachta indica (Neem) oil and Imidacloprid (IRON 30SC) on the population dynamics of Brevicoryne brassicae, Lipaphis pseudobrassicae and Plutella xylostella on white cabbage

Article PurchasedThe effects of neem seeds oil and Imidacloprid (Iron 30SC) systemic insecticide on the populations of three cabbage pests, Brevicoryne brassicae, Lipaphis pseudobrassicae and Plutella xylostella were studied. The study was conducted between June and September 2015. Oil extracts of neem were sprayed on cabbage plants to control these pests. A standard systemic chemical insecticide (IRON 30SC) was used as comparative product. The experiment was conducted in a randomized complete block design and each treatment was replicated four times. The effects of plant extracts on the population dynamics of the pests’ species, the loss level and yield were assessed. Significantly more pests infested the control plants compared to treated plants (P ≤0.05). The mean weight of cabbage heads on the sprayed plots was not significantly heavier than that of the control unsprayed plots. The use of A. indica seeds oil and Imidacloprid systemic insecticide reduced the loss level by 6.06% and 9.92%, respectively. So, the use of this neem extracts can be ameliorated by spraying at a weekly basis and can be incorporated into an overall control programme of these pests