220 research outputs found

    Spacing and Genotype on Height and Diameter Growth of Four Eucalyptus under Short Rotation

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    In this paper, the dynamic change in tree height, diameter at breast height (dbh), and ground line diameter (gld) at different density was studied. Trial sites were established in Chepkoilel and Nangili areas of western Kenya.  Eight tree species (2 hybrid eucalyptus clones; GC 10 and GC 167), 1 eucalyptus local landrace, 2 agroforestry (Grevillea robusta and Markhamia lutea), 1 pure eucalyptus (Eucalyptus grandis), and 2 preferred local species (Maesopsis eminii and Khaya nyasica) were planted on each site. This paper however focuses on the effect of spacing  on the height, dbh, and  gld growth of the 4 eucalyptus genotypes viz (2 eucalyptus hybrid clones, 1 eucalyptus local landrace, and 1 pure Eucalyptus grandis). These were planted at 10 different spacings (0.6-, 0.8-, 1.0-, 1.2-, 1.4-, 1.6-, 1.8-, 2.0-, 2.2-, and 2.4-by-1.0 m; these being some of the most common spacings used by farmers) in a Nelder radial experimental design in 4 replications. Measurements of height, dbh, and gld were taken at intervals of 6 months over 3 years. The data was subjected to an analysis of variance to determine if there were statistically significant (p = 0.05) differences in tree growth with spacing levels.  The results showed that tree growth  was significantly  influenced  by spacing  and genotype  with  the  best  spacing being  2.4-by-1.0 m, indicated that the relative growth rates of height dbh, gld, and increased with increasing the distance between trees but decreased with age. After 3 years the best spacing for optimal overall tree growth was 2.4-by-1.0 m and GC10 being the outstanding genotype. Of the 2 sites, trees performed better in Nangili. The results from this study further pinpoint the importance of species-site-matching using improved germplasm and planting trees at the correct spacing for optimal growth

    Five Year Growth and Survival of Eucalyptus Hybrid Clones in Coastal Kenya

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    Twelve eucalyptus hybrid clones (6 grandis-camaldulensis i.e. GC and 3 grandis-urophylla i.e. GU hybrids) and 3 local landraces (E. camaldulensis, E. tereticornis, and E. urophylla) were established in Gede, Sokoke, and Msambweni in the Coast Province of Kenya in 2002, to compare growth, survival, and adaptability in the 3 sites.  By the end of the 1st year, trees in Sokoke were more than 3 times the mean height of those in Gede and Msambweni. However, these growth advantages during the 1st year in Sokoke were not maintained and by year 2 Gede had caught up, although Msambweni still lagged behind. By age 5 there were significant growth differences between clones. Of the tree sites, Msambweni had the lowest tree growth.  GC167, GC14, GC581, and GC584 proved themselves as the better clones, while E. camaldulensis and E. urophylla were the better local land races. Overall, the “local land races” performed poorly in all sites.  Survivals were over 80% in all sites for the best performing clones. However, in Sokoke, 1 clone died (GU7) while another (GU8) had a survival of less than 20%, while EC and ET had survivals less than 35%. GC796 died in Msambweni and had 8% survival at Gede. The poor survivals in Sokoke may have been due to a severe drought in the 3rd year.  The initial outstanding growth performance in Sokoke may have been due to the fact that Sokoke was a ‘virgin’ forest site and presumably more fertile than the other two sites. These results show that recommendations on outstanding clones or new germplasm for planting or sale to farmers are best done at the end of the rotation for a particular intended product or use

    Effect of Charcoal Earth Kilns Construction and Firing on Soil Chemical Characteristics

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    Assessments of localized ecological and environmental impacts of charcoal production including effects on soils at kiln sites is seldom undertaken, with more emphasis being placed on the global effects of the practice such as forest degradation and deforestation. A study was undertaken in Narok, Eldoret, Moiben, and Turbo in Kenya on known charcoaling sites to investigate the impact of charcoal production on the soil chemical characteristics. Composite soil samples from 12 sampling points for all study sites were taken randomly at a depth of 0–15 cm. The samples were conditioned and analyzed for pH, particle size, Cation Exchange Capacity (CEC), extractable phosphorus, organic carbon, nitrogen, and exchangeable bases. A comparison of the soil properties between undisturbed sites and charcoaling sites showed significant differences for all chemical properties except CEC, Mg, and K. For the Moiben site, only the pH showed no significant difference (p < 0.05).  The observed high carbon content reduced with time for the one year following charcoaling activity and was attributed to soil erosion since charcoal production activities reduced the sites vegetation cover. Most chemical changes positively enhanced the nutrients content and availability, but were short lived probably due to soil erosion.  These results demonstrate the need to adopt technologies with minimum impact on the soil, or a shift to centralized production sites outside forest ecosystems or farmlands.

    Spacing and Genotype on Height and Diameter Growth of Four Eucalyptus under Short Rotation

    Get PDF
    In this paper, the dynamic change in tree height, diameter at breast height (dbh), and ground line diameter (gld) at different density was studied. Trial sites were established in Chepkoilel and Nangili areas of western Kenya.  Eight tree species (2 hybrid eucalyptus clones; GC 10 and GC 167), 1 eucalyptus local landrace, 2 agroforestry (Grevillea robusta and Markhamia lutea), 1 pure eucalyptus (Eucalyptus grandis), and 2 preferred local species (Maesopsis eminii and Khaya nyasica) were planted on each site. This paper however focuses on the effect of spacing  on the height, dbh, and  gld growth of the 4 eucalyptus genotypes viz (2 eucalyptus hybrid clones, 1 eucalyptus local landrace, and 1 pure Eucalyptus grandis). These were planted at 10 different spacings (0.6-, 0.8-, 1.0-, 1.2-, 1.4-, 1.6-, 1.8-, 2.0-, 2.2-, and 2.4-by-1.0 m; these being some of the most common spacings used by farmers) in a Nelder radial experimental design in 4 replications. Measurements of height, dbh, and gld were taken at intervals of 6 months over 3 years. The data was subjected to an analysis of variance to determine if there were statistically significant (p = 0.05) differences in tree growth with spacing levels.  The results showed that tree growth  was significantly  influenced  by spacing  and genotype  with  the  best  spacing being  2.4-by-1.0 m, indicated that the relative growth rates of height dbh, gld, and increased with increasing the distance between trees but decreased with age. After 3 years the best spacing for optimal overall tree growth was 2.4-by-1.0 m and GC10 being the outstanding genotype. Of the 2 sites, trees performed better in Nangili. The results from this study further pinpoint the importance of species-site-matching using improved germplasm and planting trees at the correct spacing for optimal growth

    Five Year Growth and Survival of Eucalyptus Hybrid Clones in Coastal Kenya

    Get PDF
    Twelve eucalyptus hybrid clones (6 grandis-camaldulensis i.e. GC and 3 grandis-urophylla i.e. GU hybrids) and 3 local landraces (E. camaldulensis, E. tereticornis, and E. urophylla) were established in Gede, Sokoke, and Msambweni in the Coast Province of Kenya in 2002, to compare growth, survival, and adaptability in the 3 sites.  By the end of the 1st year, trees in Sokoke were more than 3 times the mean height of those in Gede and Msambweni. However, these growth advantages during the 1st year in Sokoke were not maintained and by year 2 Gede had caught up, although Msambweni still lagged behind. By age 5 there were significant growth differences between clones. Of the tree sites, Msambweni had the lowest tree growth.  GC167, GC14, GC581, and GC584 proved themselves as the better clones, while E. camaldulensis and E. urophylla were the better local land races. Overall, the “local land races” performed poorly in all sites.  Survivals were over 80% in all sites for the best performing clones. However, in Sokoke, 1 clone died (GU7) while another (GU8) had a survival of less than 20%, while EC and ET had survivals less than 35%. GC796 died in Msambweni and had 8% survival at Gede. The poor survivals in Sokoke may have been due to a severe drought in the 3rd year.  The initial outstanding growth performance in Sokoke may have been due to the fact that Sokoke was a ‘virgin’ forest site and presumably more fertile than the other two sites. These results show that recommendations on outstanding clones or new germplasm for planting or sale to farmers are best done at the end of the rotation for a particular intended product or use

    Production de matiÚres premiÚres et fabrication des médicaments à base de plantes médicinales

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    Les plantes constituent un rĂ©servoir pour les pharmacopĂ©es du monde. Plusieurs mĂ©dicaments importants sont fabriquĂ©s Ă  partir des substances actives d’origine vĂ©gĂ©tales. En outre de nombreux mĂ©dicaments modernes ont Ă©tĂ© fabriquĂ©s Ă  partir de ces matiĂšres premiĂšres. Les plantes mĂ©dicinales sont utilisĂ©es directement sous forme fraĂźche, sĂšche ou transformĂ©e, stabilisĂ©e, ou extrait ou formulĂ©e avec d’autres plantes ou excipients de synthĂšse. Dans tous les cas, la matiĂšre vĂ©gĂ©tale utilisĂ©e pour fabriquer la forme posologique doit faire preuve de son efficacitĂ©, son innocuitĂ© et ĂȘtre de qualitĂ© conforme aux exigences de la PharmacopĂ©e EuropĂ©enne pour les phytomĂ©dicaments, garantissant ainsi sa sĂ©curitĂ© d’emploi. Pour ce faire, l’Organisation Mondiale de la SantĂ© (OMS) a mis Ă  la disposition des Ă©tats membres des guides et standards permettant d’harmoniser et de sĂ©curiser leur utilisation. Ainsi de nombreux pays africains ont adoptĂ© ces outils aprĂšs des modifications appropriĂ©es pour faire progresser la recherche et le dĂ©veloppement (R&D) de mĂ©dicaments Ă  base de plante. Le but de ce travail Ă©tait de faire une synthĂšse des diffĂ©rentes Ă©tapes de production, de contrĂŽle qualitĂ© et de  standardisation des matiĂšres premiĂšres issues des plantes mĂ©dicinales et des mĂ©dicaments Ă  base de plantes mĂ©dicinales.Mots clĂ©s : PharmacopĂ©e, mĂ©dicaments, mĂ©decine traditionnelle, sĂ©curitĂ© d’emploi, phytomĂ©dicaments. English title: Production of raw materials and manufacturing of drugs from medicinal plants Plants are a reservoir for the world's pharmacopoeias. Several important medicines are made from active substances of plant origin. In addition, many modern medicines have been made from these raw materials. Medicinal plants are used directly in fresh, dry or processed, stabilized, or extracted form or formulated with other plants or synthetic excipients. In all cases, the herbal material used to manufacture the dosage form must demonstrate its efficacy, safety and be of a quality that meets the requirements of the European Pharmacopoeia for phytomedicines, thus ensuring its safe use. To this end, the World Health Organization (WHO) has made available to Member States guides and standards to harmonize and secure their use. Thus, many African countries have adopted these tools after appropriate modifications to advance research and development (R&D) of plant-based drugs. The aim of this work was to make a synthesis of the different stages of production, quality control and standardization of raw materials from medicinal plants and herbal medicines.Keywords: Pharmacopoeia, drugs, traditional medicine, safe use, phytomedicines

    Trypanocidal and leishmanicidal activity of six limonoids

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    Six limonoids [kotschyienone A and B (1, 2), 7-deacetylgedunin (3), 7-deacetyl-7-oxogedunin (4), andirobin (5) and methyl angolensate (6)] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major. Whereas all compounds showed anti-trypanosomal activity, only compounds 1–4 displayed anti-leishmanial activity. The 50% growth inhibition (GI 50) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.5 and 14.9 ΌM. Kotschyienone A (1) was found to be the most active compound with a minimal inhibition concentration (MIC) value of 10 ΌM and GI 50 values between 2.5 and 2.9 ΌM. Only compounds 1 and 3 showed moderate cytotoxicity against HL-60 cells with MIC and GI 50 values of 100 ΌM and 31.5–46.2 ΌM, respectively. Compound 1 was also found to show activity against intracellular amastigotes of L. major with a GI 50 value of 1.5 ΌM. The results suggest that limonoids have potential as drug candidates for the development of new treatments against trypanosomiasis and leishmaniasis

    HIV Genetic Diversity in Cameroon: Possible Public Health Importance

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    To monitor the evolving molecular epidemiology and genetic diversity of HIV in a country where many distinct strains cocirculate, we performed genetic analyses on sequences from 75 HIV-1-infected Cameroonians: 74 were group M and 1 was group O. Of the group M sequences, 74 were classified into the following env gp41 subtypes or recombinant forms: CRF02 (n = 54), CRF09 (n = 2), CRF13 (n = 2), A (n = 5), CRF11 (n = 4), CRF06 (n = 1), G (n = 2), F2 (n = 2), and E (n = 1, CRF01), and 1 was a JG recombinant. Comparison of phylogenies for 70 matched gp41 and protease sequences showed inconsistent classifications for 18 (26%) strains. Our data show that recombination is rampant in Cameroon with recombinant viruses continuing to recombine, adding to the complexity of circulating HIV strains. This expanding genetic diversity raises public health concerns for the ability of diagnostic assays to detect these unique HIV mosaic variants and for the development of broadly effective HIV vaccines.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63150/1/aid.2006.22.812.pd

    HIV and STI Prevalence among Female Sex Workers in CĂŽte d'Ivoire: Why Targeted Prevention Programs Should Be Continued and Strengthened

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    Objective: To assess condom use and prevalence of STIs and HIV among female sex workers (FSWs), as part of a comprehensive monitoring and evaluation plan of a nationwide sex worker prevention project in Cîte d’Ivoire. Design and Methods: Cross sectional surveys were conducted among FSWs attending five project clinics in Abidjan and San Pedro (2007), and in Yamoussoukro and Gagnoa (2009). A standardized questionnaire was administered in a face-toface interview, which included questions on socio-demographic characteristics, sexual behaviour and condom use. After the interview, the participants were asked to provide samples for STI and HIV testing. Results: A total of 1110 FSWs participated in the surveys. There were large differences in socio-demographic and behavioural characteristics between FSW coming for the first time as compared to FSW coming on a routine visit. The prevalence of N. gonorrhoeae or C.trachomatis was 9.1%, 11.8 % among first vs. 6.9 % routine attendees (p = 0.004). The overall HIV prevalence was 26.6%, it was lower among first time attendees (17.5 % as compared to 33.9 % for routine attendees, p,0.001). The HIV prevalence among first attendees was also lower than the proportion of HIV positive tests from routine testing and counselling services in the same clinics. Conclusions: The results show a relatively high STI and HIV prevalence among FSWs in different cities in Cîte d’Ivoire. In th

    Effect of Charcoal Earth Kilns Construction and Firing on Soil Chemical Characteristics

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    Assessments of localized ecological and environmental impacts of charcoal production including effects on soils at kiln sites is seldom undertaken, with more emphasis being placed on the global effects of the practice such as forest degradation and deforestation. A study was undertaken in Narok, Eldoret, Moiben, and Turbo in Kenya on known charcoaling sites to investigate the impact of charcoal production on the soil chemical characteristics. Composite soil samples from 12 sampling points for all study sites were taken randomly at a depth of 0–15 cm. The samples were conditioned and analyzed for pH, particle size, Cation Exchange Capacity (CEC), extractable phosphorus, organic carbon, nitrogen, and exchangeable bases. A comparison of the soil properties between undisturbed sites and charcoaling sites showed significant differences for all chemical properties except CEC, Mg, and K. For the Moiben site, only the pH showed no significant difference (p < 0.05).  The observed high carbon content reduced with time for the one year following charcoaling activity and was attributed to soil erosion since charcoal production activities reduced the sites vegetation cover. Most chemical changes positively enhanced the nutrients content and availability, but were short lived probably due to soil erosion.  These results demonstrate the need to adopt technologies with minimum impact on the soil, or a shift to centralized production sites outside forest ecosystems or farmlands.
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