Exoscopy of Detrital Zircons from Niamey Neoproterozoic Sandstones (Eastern Edge of the West African Craton, Southwestern Niger): Interpretation of Detrital Sediments Provenance

This study focuses on exoscopic analyses of detrital zircon grains of Archean and Paleoproterozoic age, contained in the sediments from the Niamey Neoproterozoic sandstones (Niamey region), with a view to confirming the sediments sources already proposed (Kénéma-Man domain for Archean-age zircons and Baoulé Mossi domain for Paleoproterozoic-age zircons). Exoscopic analysis reveals that Archean zircon grains are more corroded, with rounded to sub-rounded shapes, while Paleoproterozoic zircon grains are less corroded and mostly angular in shape. The strong corrosion of Archean zircon grains, implying long-distance transport, is consistent with the remoteness of the Kenema-Man domain which are the source these sediments. The fact that the Paleoproterozoic zircon grains show little or no wear implies a proximal source of sediments, corresponding to the Baoulé Mossi domain.

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

A regional study connecting geolelectrical surveys with geology and hydrogeology was carried out in the western part of the Iullemmeden basin, precisely in the Dosso region in Niger. One hundred and four (104) vertical electrical sounds have been realized, among them nineteen representative were thus be used as parametric surveys. The local resistivity values of the geological formations of Quaternary range from 100 Ω⋅m to 1000 Ω⋅m (sands and lateritic sandstones). The Oligo-Miocene formation of the Continental terminal (Ct) shows resistivity values ranging from 1 to 5 Ω⋅m (brackish groundwaters) to 1500 Ω⋅m (clay sandstones) while the Upper Cretaceous formation of the Continental “hamadien” (Ch) indicates values ranging from 20 Ω⋅m (sandy clay) to 5000 Ω⋅m (clayey sandstones). The geological formations of Paleocene have values from 2 Ω⋅m (marls) to 60 Ω⋅m (calcareous marl), while the Precambrian basement exhibits values of granite around 300 Ω⋅m to 60,000 Ω⋅m. The update of the structural settings reveals many faults in the study area which explain both the shape of the basin and the geometry of the aquifers. Tectonics is also consistent with the hydraulic characteristics of aquifers. In addition, brackish groundwaters were identified as perched aquifer groundwaters in different depths in Dosso region. They probably come from the marine brines during the regression of the Paleocene Sea.

Petrology of Spinel-Lherzolite Xenoliths from Mazéléand Others Northen Xenoliths Localities of Cameroon Volcanic Line: Exchange Reactions and Equilibrium State

The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki, Mazélé in the NE of Ngaoundéré, Tello and Ganguiré in the SE of Ngaoundéré and Likok, locality located in the west of Ngaoundé). The peridotite enclaves of the above localities show restricted mineralogical variation. Most are four-phase spinel-lherzolites, indicating that this is the main lithology that forms the lithospheric mantle below the shallow zone. No traces of garnet or primary plagioclase were detected, which strongly limits the depth range from which the rock fragments were sampled. The textures and the wide equilibrium temperatures (884˚C - 1115˚C) indicate also entrainment of lherzolite xenoliths from shallow depths within the lithosphere and the presence of mantle diapirism. The exchange reactions and equilibrium state established in this work make it possible to characterize the chemical composition of the upper mantle of each region and test the equilibrium state of the phases between them. Variations of major oxides and incompatible elemental concentrations in clinopyroxene indicate a primary control by partial melting. The absence of typical “metasomatic” minerals, low equilibration temperatures and enriched LREE patterns indicate that the upper mantle below septentrional crust of Cameroun underwent an event of cryptic metasomatic enrichment prior to partial melting. The distinctive chemical features, LREE enrichment, strong U, Ce and Pr, depletion relative to Ba, Nb, La, Pb, and T, fractionation of Zr and Hf and therefore ligh high Zr/Hf ratio, low La/Yb, Nb/La and Ti/Eu are all results of interaction of refractory peridotite residues with carbonatite melts.

Effects of Scarification and Substrates on Seed Germination Quality for Domestication of Stereospermum kunthianum(Bignoniaceae)

The demand for medicinal plants at the origin of phyto-drugs,like all ethnobotanical plants,threatens their existence today.The aim of this work was to determine suitable methods for optimizing the possibilities of regenerating Stereospermum kunthianum.To achieve this objective,3 levels of mechanical scarification(light scarification,medium scarification and deep scarification)were applied to the seeds of this species using a rough instrument,and 5 days after germination,the seedlings were transplanted into 5 types of substrate to study their effects on seedling growth.The length of the seedlings was measured using a graduated ruler.The results obtained showed that the best latency time was 2 days for average seed scarifications.The highest germination half-time was 4.00±0.06 days observed for average seed scarification,the highest germination speed was 22.50±1.00 and the highest germination rate was 100.00%±0.00%for average scarification.The homogeneous substrate mixes black earth/woodsilk and Fine sand/woodsilk were more effective for seedling growth(1.9 cm/day in the juvenile state)and development.Medium seed scarification is the most effective method for regenerating Stereospermum kunthianum,and the black earth/wood shavings substrate mix is the best for its cultivation.

Metallogeny and Emplacement Conditions of Continental Terminal 3 (Ct3) Iron Formations of the Niamey Region (Western Niger)

This study aims to characterize the different lithofacies of the Ct3 formation in the Niamey region, and to determine the distribution of major and trace elements, in order to highlight the conditions for the establishment of iron mineralization. A lithological column, synthesizing sections of selected outcrops in the vicinity of Niamey, was produced. The chemical compositions of the selected samples were determined by X-ray fluorescence (XRF) spectrometry. Microscopic analysis of the thin sections determined the gœthitic nature of the oolitic iron ore. The oolites show a quartz, limonitic or gœthitic nucleus. Sometimes the nucleus is absent. From a morphoscopic point of view, two types of oolites have been distinguished: spherical-shaped and ellipsoidal-shaped oolites. The oolites are either contiguous or disseminated, as the case may be, in a limonitic to goethitic cement or in a fine sandstone matrix. The larger oolites (pisolites) are relatively friable. They reflect the influence of a relatively turbulent to submerged environment. The hardground of the iron mineralized horizons are covered by quartz grains. They are indicative of a submerged or emergent environment. X-ray fluorescence analysis shows high Fe2O3 contents (50% to 80%) and variable contents of major elements SiO2, Al2O3, TiO2, MnO, MgO, CaO, K2O and P2O5 associated with certain trace elements such as Th, U, V, Y, Zn, Zr and As. The results of the study are an important tool for decision-makers to adopt effective prevention/remediation measures for groundwater contamination in the Continental terminal aquifer systems.

Petrography and Geochemical Characterization of Dolerites from Figuil (Northern Cameroon) and Léré(Southwestern Chad)

This work presents the petrographic and geochemical data of the dolerite dykes crosscutting the Pan-African basement of Figuil (North-Cameroon) and Léré (South-West Chad) in order to approach their petrogenesis and their emplacement context. Two groups of dolerites have been highlighted by petrographic and geochemical studies. These groups were discriminated by their TiO2, Fe2O3, REE, Ba, Nb, Zr, La and Hf contents which are relatively higher in group I;group II, on the other hand, has higher MgO, Mg#, Sc, Ni and Cr contents. The mineralogical assemblage of these dolerites is made up by plagioclases, pyroxenes, olivine, oxides, amphibole, biotite and sometimes pyrite, calcite, apatite, epidote and chlorite. The behaviour of the major and trace elements suggest that studied dolerites have an evolution dominated by fractional crystallization. Most dolerite samples show higher REE concentrations and (La/Yb)N > 8.7, (Tb/Yb)N > 1.9 and Dy/Yb > 2 ratios characterizing a garnet-bearing mantle. The difference in incompatible elements between the two groups is explained by the degree of partial melting of the same source which becomes more important over time. Low (Ce/Yb)N values (3.3 - 11.58) also suggest relatively low partial melting degree of the source. Fractional crystallization process was possibly combined with minor crustal contamination as shown by enrichment of Th/Yb from group II to Group I that might be due to turbulent magma emplacement. The chemical compositions of these dolerites are similar to that of continental tholeiites with slightly moderate negative Nb-Ta anomalies which are attributed to crustal contamination of magmas. As other dolerites of Cameroon, continental tholeiitic signature of the studied dolerites is evidenced in geotectonic discrimination diagrams with Group II dolerite compositions falling within the field of tholeiitic basalts and group I within the field of alkali basalts.

Granitoid Rocks in Guider Area(North Cameroon):Contribution of Petrography and Structural Analysis

The study area is located around Guider and belongs to the Northern Cameroon Pan-African fold belt.It is essentially made of three generations of granitoids.The first generation G1 comprises diorites,tonalites and granodiorites.The second one G2 is constituted by biotite granites and biotite-muscovite granites deformed in the solid-state.The third generation G3 is constituted by biotite-syenites,monzosyenites,and leucogranites. All the granitoids are cross cut by aplite veins

Study of Multi-Origin Hazards and Assessment of Associated Risks in the Lefo Caldera (Bamenda Volcano, Cameroon Line)

The Bamenda Volcano (BV) (2621 m) is a stratovolcano situated in the Cameroon Line (CL). BV includes Mount Lefo (2534 m) which is situated on its southern slopes and contains one elliptical caldera (3 × 4 km). This caldera is propitious to farming and breeding activity. Despite these profitable assets, Lefo caldera (LC) is an amphitheater of the occurrence of multi-origin hazards that have direct or indirect impacts on the biodiversity and human patrimony. The most present hazards are those of meteorological origin. Numerous combined factors (steepest slopes, heavy rainfalls, weathered state of volcanic products…) rule these hazards. These factors gave rise to the occurrence of landslides, gullies erosion and rock falls which occur precisely on caldera northern and eastern rims. Hazards of anthropogenic origin are based on the destruction of the vegetation cover by the population for dealing, firewood and building issues. Moreover, during the breeding activity, the cattle covers the caldera throughout the day;this unevens the topography and destroys the meadow. Hazards of volcanological origin are not yet occurring in LC;but the recent Lake Monoun (1984) and Nyos (1986) CO2 eruptions, mount Cameroon eruptions (1999 and 2000) and mount Oku Lake event (2011) which are close to the BV and, the age of 0 Myr of basalt, constitutes a subject of controversy toward the reactivation of the Cameroonian hotspot faults. The assessment of risks in LC was based on the average income of breeding activity and house investment. The economy of LC is valued at about US$527472.527. The level of such risk will be important in case of loss of human beings and the destruction of geomorphosites’ values. In order to reduce the level of looses in this zone, hazard and risks maps are provided in this paper as well as some recommendations.

Fractional Crystallization and Crustal Contamination of Doleritic and Trachytic Dykes Crosscutting the Cretaceous Sedimentary Basins from Figuil (North Cameroon) and Léré(South-Western Chad): Geodynamic Implications

Magmatism in the Cretaceous sedimentary basins of the Figuil and Léré regions constitutes one of the fundamental parameters in the reconstruction of the history of the Cretaceous sedimentary basins. The main objective of this paper is to constrain the petrogenetic processes of hypovolcanic rocks and to determine their geodynamic context of emplacement. The petrographic study of mafic hypovolcanic and trachytic rocks was carried out under a polarizing microscope on thin sections. For the geochemical study, the major oxides and some trace elements were analyzed by ICP-AES. Trace and rare earth elements were analyzed by ICP-MS. The dolerites of the Cretaceous sedimentary basins are composed of dykes of amphibole bearing dolerites, biotite and pyroxene bearing dolerite, pyroxene bearing dolerites and trachytes. The dykes are in the order of 20 to 100 m wide by several kilometers long and oriented from N23°E to N90°E. The textures of these rocks are sub-ophitic to intergranular for dolerites and trachytic for evolved rocks (trachytes). The geochemical study shows that the dolerites are basaltic in composition with alkaline to subalkaline character. The sampled dykes have an evolution dominated by fractional with the minor impact of the crustal assimilation characterized by low Rb/Y ratios for dolerites (0.36 - 0.97) and high values of Rb/Y for the Pan-African granitoids’ samples (1.95 - 4.01). The nature of doleritic and trachytic magma sources is supported by their (Tb/Yb)N > 1.9 (1.91 - 3.79) and Dy/Yb > 2 (2.32 - 3.50) ratios of most samples, which suggests melting in a garnet-bearing mantle. Concerning the geodynamic context of the studied rocks, doleritic samples are classified as within-plate tholeiite and volcanic arc basalt, and within-plate alkali basalts.

Identification of major sources controlling groundwater geochemistry in Mount Makabaï in the Far-North of Cameroon(the northernmost part of the Pan-African Belt)

The present work focuses on the volcanic basement rock geochemistry of Mount Makabaï(MarouaCameroon city)in relation to groundwater geochemistry.Investigations were centered on an approach involving an association of several methods such as geological cartography,hydrogeology,and geochemistry.Three rock samples,four disturbed soil samples,three undisturbed soil samples,and 20 samples of groundwater in 10 wells were collected during fieldwork and prepared for laboratory analyses.Bedrocks exhibit porphyritic,aphyric,and subaphiric textures.The phenocryst phases are mainly olivine,clinopyroxene,and plagioclase.Based on whole rock major element chemical compositions,the Makabaï samples,plotted on Na_(2)O+K_(2)O versus SiO_(2)diagram,are mugearite,hawaiite,and basalt.The ratio of(MgO+CaO)/(Na_(2)O+K_(2)O)exceeds unity and shows dominance of alkaline Earth metals(MgO:2.99-4.48%;CaO:6.19-9.80%)relatively to alkali metals(Na_(2)O:2.27-4.46%;K_(2)O:2.09-2.51%).Exchangeable base contents are high,mostly represented by Ca and Mg,whose contents vary from 14.6 to 35.28 cmol(+)kg^(-1)and from 3.28 to9.48 cmol(+)kg^(-1)respectively.The CECclayis likewise high,fluctuating between 116.80 and181.38 cmol(+)kg^(-1),values in line with the presence of 2:1 clay minerals represented in the study area by montmorillonite.In the water samples,the Ca2+and Na+contents are generally higher than K^(+)and Mg^(2+),reflecting the relative abundance of Na_(2)O and CaO oxides to K_(2)O and MgO oxides in rocks where different waters were sampled.The waters of Makabaï are acidic to neutral(6.3≤pH≤7.4)and weakly to highly mineralized(110.0≤EC≤1190.0μS/cm).Hydro-geochemical classification by using the Piper diagram revealed two water types:(1)CaMg-HCO_(3)(40%)and(2)CaMg-Cl or CaMg-SO4(60%).The average content of ions in all the analyzed samples was HCO_(3)^(-)>>NO_(3)^(-)>SO_(4)^(2-)>Cl-for anions and Ca^(2+)>>Mg^(2+)>Na^(+)>K^(+)for cations.Major mechanisms governing ionic constituents of groundwater in the study area are water-rock interactions,silicate weathering,and ion exchange.

Study of the Germination of Scarified Seeds of Burkea africana Hook. For Its Domestication in Chad

The objective of this work was to determine new approaches that could improve the germination quality of Burkea africana seeds under reproducible conditions and by means available to farmers with a view to its propagation. The tests concerned the influence of three pre-germinative treatments. It is about the light scarification (Scl), medium scarification (Scm) and deep scarification (Scd) of seeds in order to determine some parameters of germination that are the latency time, the time of germination, the rate of germination and the speed of germination. The treated seeds were sown in transparent germinators lined with hydrophilic paper and then after the appearance of radicles, the plants were transplanted on five types of substrates (black soil, fine sand, sawdust, mixtures 1/1 of sawdust-black soil and 1/1 of sawdust-fine sand). The results obtained by the deep (Scp) and medium (Scm) scarification compared to those of the light scarification and the control, showed a clear reduction of the lag time (3 days/15 days (control). At the 5% threshold, germination times 6.27 × 10-1 (Scd) and 6.01 × 10-1 (Scm) were significantly influenced. Germination rates 4.18 × 10-1 (Scd) and 3.92 × 10-1 (Scm) are also influenced by the pretreatment. Germination rates are significantly improved (80%). Regardless of the under treatment, the substrate “sawdust and fine sand” improves the germination of scarified seeds by 14.07% more compared to the substrate “fine sand” at the 5% threshold. The mechanical scarification and the type of substrates thus influence positively and homogeneously the germination of seeds of Burkea africana. The domestication of this species is thus possible and can be considered for useful purposes.

Impact of Pretreatment on the Germinative Characters of Seeds of Stereospermum kunthianum Cham. (Bignonaceae) for Its Domestication in Chad

The objective of this research is to lift the dormancy of seeds of S. kunthianum in with a view to domesticating them. In this experiment, we used the soaking of seeds in sulfuric acid for different durations (10 min, 30 min and 1 h). The treated seeds were sown in transparent germinators. The explants obtained were then transplanted into pots containing five types of substrate (black earth, fine sand, sawdust, mixtures 1/1 of sawdust/black earth and 1/1 of sawdust/fine sand). This second test made it possible to determine the rate of germination on the substrate. The results obtained compared to those of the control showed a clear reduction in the latency time or germination time (62 hours) instead of 6 days (control), in the germination time 3 days/7 days (control) and a very high germination rate (100%). At the 5% threshold, soaking for 10 min and 30 min (100%) is the best result on the germination of S. kunthianum seeds. Soaking for 1 hour gives (7%) very low. After transplantation of the explants, the percentages obtained independently of the treatments show that the 1/1 mixtures of sawdust/black earth (75.19%), black earth (73.33%) and sawdust/fine sand (66.30%) have a higher performance than the others. The type of germination is epigeal. This work makes it possible to domesticate S. kunthianum in Chad.

Antioxidant activity of water-soluble polysaccharide extracted from Eucalyptus cultivated in Lebanon

Objective: To extract and identify the chemical composition of the polysaccharide isolated from the Eucalyptus cultivated in Lebanon and to evaluate its antioxidant activity.Materials: The water-soluble polysaccharide was isolated from Eucalyptus leaves, and its structure was identified by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance. The antioxidant activity of the active ingredient was screened for its radical scavenging ability using 2,2-diphenyl-1-picryl-hydrazyl radical(DPPH) test.Results: The results of the DPPH test have shown that fucoidan, the polysaccharide isolated from Eucalyptus, exhibited almost the same antioxidant activity against DPPH$as the ascorbic acid did at 100 mg/mL.Conclusions: This natural molecule extracted from a medicinal plant has a promising antioxidant activity and could be used in pharmaceutical and medical applications.

Mineral Chemistry of Wehrlite Xenoliths Hosted in Basalts from the SW of Hossere Dammougalre(Adamawa Plateau,Cameroon):Thermobarometric Implications

Wehrlite samples (size: ~4 cm) hosted in basaltic lavas from the SW of Hosséré Dammougalré are located in the western Adamawa Plateau. Porphyritic and allotriomorphic texture characterize respectively host Basalt and wehrlite xenoliths. The phenocrysts of olivine (Fo68&minus;74), and Ti-magnetite are scattered in host basalt. Wehrlite xenoliths (~4 cm size) contain Cr-rich clinopyroxene (diopise-augite), olivine (Fo76&minus;88) and chromiferous spinel. Equilibrium temperatures calculated from Fe/Mg exchange reaction for olivine/spinel vary between 944&#176;C and 1102&#176;C. The wehrlite olivine crystals with low Fo (<90) indicate a re-equilibration of Fe-Mg in the host basalt at low temperatures. All the analyzed wehrlite clinopyroxenes have crystallized at high pressures as evidenced by the Alvi and Aliv contents. The studied spinel-bearing wehrlite xenoliths represent probably the residual portions of the upper mantle, which are an important source of information about lithospheric composition and thermal evolution beneath the Adamawa Plateau.

Granitic inselbergs of Lara(Panafrican Chain,Far-North Cameroon):Assets for the implementation of geotourism in Mountainous region

The locality of Lara(Far-North Region,Cameroon)is made up of a pediplain strewn with coalescent plutons.The interaction of internal and external geological processes has contributed to transform the latter into inselbergs,whose geotouristic values are yet to be studied.Field and laboratory work enabled us to select the geomorphosites through their aesthetic value(particular size and shape)and,geomorphological and geological features.Moreover,it permitted to study and map the geomorphosites using Optic Microscope,Google Earth,GIS software and many other interfaces.Hence,four inselbergs have been selected and studied in the locality of Lara.The petrographic study of these inselbergs shows that granites are the main components of inselbergs and they present a fine to coarse-grained texture,materialized by quartz,micas,plagioclases and alkali feldspars(white and pink in colour).Inselbergs exhibit vertical and parallel networks of diaclases giving them a stratified appearance in some flanks.In addition,on some inselberg limbs and piedmonts,are built tors which contribute to their beauty.The tops of inselbergs,are embellished by several alluring pedestal rocks.On their flanks,shelters of various shapes and sizes(about 12 m length)have developed through the heaps of blocks field.Among the ten shelters selected,some have a fairly high cultural value as they are sacred places for the local population.Moreover,Lara's granitic inselbergs include enclaves(cognate enclaves and xenocrysts)that also significantly improve their geoheritage value.Inselbergs are landforms with high education and aesthetic value that attracted a larger local and foreign population of about 863 visitors between 2017-2019.They constitute an exceptional geoheritage that could attract more tourists in the locality of Lara;but the promotion of geotourism is needed through interpretative panels,marketing of geomorphosites through leaflets,web,media,and geotours,to mention a few.

Waste Related Pollutions and Their Potential Effect on Cancer Incidences in Lebanon

Pollution represents an important threat to human health. Waste pollution with its adverse health risks, mainly cancer incidences, is one of the main issues present in Lebanon. Random disposal of wastes is instilling a complex and challenging situation that is affecting the entire population. Here, a comprehensive study is presented along with collected data addressing the correlation between long-term exposure to the different forms of pollution and the chances of being affected with cancer. Lebanon, a country currently facing an extensive garbage crisis, is undergoing alarming surges in pollution rates. Inevitably, these environmental factors become chief elements in influencing disease statistics. It is therefore of urgent importance to seek all solutions possible while raising awareness in order to reduce life threatening risks.

Effect of the Various Processed Food of the Far North Cameroon on the Glycemic Index

Metabolic Syndrome (MS) has reached a pandemic proportion and has an impact on the incidence and severity of cardiovascular pathologies. This study was conducted to evaluate the effect of different processed food commonly consumed in Maroua (Far North Region, Cameroon) on the Glycemic Index (GI). To ameliorate the follow up of MS and population’s nutrition education, a survey was conducted among 200 families. The ten most consumed meals were selected after a food survey among 200 families. The meals were mostly made of a vegetable soup associated to a high carbohydrate staple. Vegetables and cereals were processed according to the food survey results. Then, a food tolerance test was performed on 30 male volunteers living in the same region. Among them, 12 were selected with an average age of 28.25 and a mean BMI of 19.63. They were studied on separate occasions in the morning after an overnight fast. After fasting, blood glucose was taken before and (15, 30, 45, 60, 90 and 120 minutes) after eating a test meal compared to sucrose and glucose solution (33.33%) used as reference. Glycemic response curves were used to calculate the gi of each meal. Results show that GI of the tested meals varied significantly (p < 0.05) between 20 and 79. Red millet porridge with kelenkelen-beans (Cochorus oletorius-Vigna unguiculata) sauce and red millet porridge with kelenkelen-peanut (Cochorus oletorius-Arachis hypogea) sauce exhibited the lowest GI. The highest GI was observed in corn porridge associated with fresh okra (Hibuscus esculentus) or with tasba (Cassia tora)-okra-beans sauce.

Reproductive Characteristics of the Kulzer’s Rock Lizard Phoenico­lacerta kulzeri(Reptilia:Lacertidae)

The present study aims to determine,by histological examination,the female reproductive cycle of specimens of Kulzer’s rock lizards collected in a mountainous region in Lebanon.Females of Phoenicolacerta kulzeri followed a seasonal reproductive pattern.Winter hibernation period lasted for 5 months.Females of P.Kulzeri exhibited a reproductive activity during spring characterized by the presence of vitellogenic follicles in the ovaries and eggs in the oviducts.Oviposition occurred throughout the springtime.Up to two clutches were produced with an average clutch size of 2.9 eggs.Clutch size was significantly correlated to female body size.The attainment of sexual maturity was at a minimum size of 46 mm snout-vent length.The mean body size of adult females was 55.0 mm and did not differ significantly from that of adult males.Females showed a period of sexual rest in summer and none of them showed a reproductive activity in autumn.The female reproductive activity of P.kulzeri was well-synchronized with that of the males in spring;however,an autumnal asynchrony was observed between the female and male reproductive cycles,since males continued to exhibit a spermatogenetic activity.

Hypolipidemic and anti-atherosclerogenic effects of aqueous extract of Ipomoea batatas leaves in diet-induced hypercholesterolemic rats

Objective:Ipomoea batatas(L.)Lam.is a food plant used in African traditional medicine to treat cardiovascular diseases and related conditions.We assessed the hypolipidemic and anti-atherosclerogenic properties of the aqueous extract of I.batatas leaves in a rat model of diet-induced hypercholesterolemia.Methods:Hypercholesterolemia was induced in male Wistar rats by exclusive feeding with a cholesterolenriched(1%)standard diet for four weeks.Then,rats were treated once daily(per os)with I.batatas extract at doses of 400,500 and 600 mg/kg or with atorvastatin(2 mg/kg),for four weeks.Following treatment,animals were observed for another four weeks and then sacrificed.Aortas were excised and processed for histopathological studies,and blood glucose level and lipid profile were measured.Results:Hypercholesterolemic animals experienced a 21.5%faster increase in body weight,significant increases in blood glucose and blood lipids(148.94%triglycerides,196.97%high-density lipoprotein cholesterol,773.04%low-density lipoprotein cholesterol,148.93%very low-density lipoprotein cholesterol and 210.42%total cholesterol),and increases in aorta thickness and atherosclerotic plaque sizes compared to rats fed standard diet.Treatment of hypercholesterolemic rats with the extract mitigated these alterations and restored blood glucose and blood lipid levels to normocholesterolemic values.Conclusion:Our findings suggest that I.batatas leaves have hypolipidemic and anti-atherosclerogenic properties and justify their use in traditional medicine.

Floristic composition,growth temperament and conservation status of woody plant species in the Cameroonian tropical rainforests

Introduction:Cameroon’s tropical rainforests are nowadays strewn with rural forests maintained by local popula‑tions;however,these forests are not officially recognized in the non‑permanent forest domain.Rural forests are non‑delimited riparian areas within the dense moist forest,reserved for rural housing,agricultural activities and agroforestry practices,freely exploited by the local communities for their livelihood without them having any rights to artisanal and commercial logging.This study aimed at contributing to the flora knowledge and the conservation state of woody plant species in rainforests.The study was carried out in two rural forests located in the Eastern and Southern agroforestry zones of Cameroon.Methods:The method adopted for floristic inventories combined a fixed area sampling unit and a variable area sampling unit.Woody individuals with diameter at breast height(dbh)<3.2 cm were counted and shrubs of 3.2≤dbh<10 cm were measured to analyse the understorey,while trees with dbh≥10 cm were measured and identified to characterize the canopy.Results:In the Essiengbot‑Mbankoho rural forest in Eastern Cameroon,468 species belonging to 61 families were recorded in the understory while 227 species belonging to 53 families were identified at the canopy level.A total of 40(7.68%)threatened species,18(3.45%)Near Threatened species and 408(78.31%)Least Concern species were recorded.In the Nbgwassa‑Opkweng rural forest in Southern Cameroon,534 species belonging to 64 families were identified in the understory while 225 species belonging to 43 families were recorded in the canopy.A total of 54(9.69%)threatened species,25(4.49%)Near Threatened species and 421(75.58%)Least Concern species were identified in this forest.Shannon’s diversity indices were above five in the understories and canopies of both forests.Shade‑bearer species were the most represented in the understories while the non‑pioneer light‑demanding and shade‑bearer species were the most abundant in the canopies.Conclusions:Despite the influence of slash‑and‑burn agriculture and subsistence farming practices,rural forests managed by local populations provide opportunities for preserving plant biodiversity.However,the presence of threatened species,pioneer species and non‑pioneer light‑demanding species in these forests is an indicator of mod‑erate and man‑induced disturbances that,in the absence of a forest management plan or sustainable management,may threaten this biodiversity.Legal management of rural forests could help in limiting the anthropogenic activities and pressures on community forests.