Strong seedling recruitment does not limit mangrove vulnerability to harvest

Ecological studies on the impacts of timber harvesting contributed to inform sustainable management strategies of tropical forests. However, these studies rely strongly on two major assumptions: (i) strong seedlings recruitment predispose for positive population dynamics, and (ii) more adult trees is a guarantee for a strong reproductive capability of the population. These assumptions are applied without accounting for the life history of the harvested species. Here, we revisit these assumptions in light of the life history theory, which predicts different responses of short- and long-lived species to perturbation. We predict that harvesting adults, rather than reducing seedling recruitment of long-lived species, would have greater impact on population dynamics. We tested our prediction on three mangrove species in South Africa. First, we reconstructed the projection matrices for three mangrove species in the Mngazana Estuary of Eastern Cape province of South Africa. Next, we simulated a range of harvest intensities for different life stages and explored how harvesting influences population dynamics. Finally, we examined the age-specific mortality trajectories for all three species. We found that populations of all three species were closer to their stable stage distribution. Contrary to popular belief, we found that changes in seedling recruitment will have minimal effects on mangrove long-term population dynamics, a finding consistent with the life history theory. However, contrary to expectation, simulating harvest of adults had minimal effect on population dynamics. This is due to low reproductive values for these late stages. Our analysis of age-specific mortality trajectories further provided evidence for positive senescence particularly for Avicennia which was the least resilient to harvest. Our findings cast doubt on the traditional forest management strategies that rely strongly on seedling density as a metric of sustainability and forbid unquestionably harvesting large individuals. We call for caution while generalizing forest management strategies irrespective of the life history of the species at hand

Prévalence et rôle des lipides dans l’avènement de l’obésité au Bénin

Le recueil des mesures anthropométriques des étudiants de l’Institut National Médico-Social (INMES) au Bénin nous a permis de calculer l’Indice de Masse Corporelle de cette population, seul indicateur pour évaluer l’état nutritionnel des adultes de point de vue énergétique. Au terme de cette évaluation, il ressort que la prévalence de l’obésité est plus élevée chez les femmes (9,81%) que chez les hommes (0,8%). L’indice de Masse Corporelle (IMC) médian est estimé à 23,03 chez les femmes contre 21,45 chez les hommes. Pour savoir les causes éventuelles de l’obésité, nous avons prélevé le sang de 41 étudiants supposés obèses et 92 ensurpoids et avons dosé les paramètres biologiques comme Cholestérol Total, Cholestérol-HDL, Cholestérol-LDL et Triglycérides. Il ressort de cette étude que, sur les quatre (04) composants lipidiques dosés, seul letaux de cholestérol-LDL est élevé au sein de cette population avec une valeur médiane de 1,52 g/l. Aussi, nous constatons une disparité dans les paramètres dosés. Par ailleurs, presque le quart (25%) des individus ensurpoids ou obèses ont une lipidémie normale. D’après nos résultats, c’est le métabolisme de Cholestérol-LDL qui est perturbé et que l’état d’obésité serait lié à d’autres facteurs tels que génétiques, hormonaux et autres

Molecular basis of permethrin and DDT resistance in an Anopheles funestus population from Benin

Open Access Journal; Published online: 20 Nov 2018Background Insecticide resistance in Anopheles mosquitoes is threatening the success of malaria control programmes. In order to implement suitable insecticide resistance management strategies, it is necessary to understand the underlying mechanisms involved. To achieve this, the molecular basis of permethrin and DDT resistance in the principal malaria vector, Anopheles funestus from inland Benin (Kpome), was investigated. Results Here, using a microarray-based genome-wide transcription and qRT-PCR analysis, we showed that metabolic resistance mechanisms through over-expression of cytochrome P450 and glutathione S-transferase genes (GSTs) are a major contributor to DDT and permethrin resistance in Anopheles funestus from Kpome. The GSTe2 gene was the most upregulated detoxification gene in both DDT- [fold-change (FC: 16.0)] and permethrin-resistant (FC: 18.1) mosquitoes suggesting that upregulation of this gene could contribute to DDT resistance and cross-resistance to permethrin. CYP6P9a and CYP6P9b genes that have been previously associated with pyrethroid resistance were also significantly overexpressed with FC 5.4 and 4.8, respectively, in a permethrin resistant population. Noticeably, the GSTs, GSTd1-5 and GSTd3, were more upregulated in DDT-resistant than in permethrin-resistant Anopheles funestus suggesting these genes are more implicated in DDT resistance. The absence of the L1014F or L1014S kdr mutations in the voltage-gated sodium channel gene coupled with the lack of directional selection at the gene further supported that knockdown resistance plays little role in this resistance. Conclusions The major role played by metabolic resistance to pyrethroids in this An. funestus population in Benin suggests that using novel control tools combining the P450 synergist piperonyl butoxide (PBO), such as PBO-based bednets, could help manage the growing pyrethroid resistance in this malaria vector in Benin

Oxidative stress in pregnancy and fertility pathologies

Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders

Comparative phylogenetic methods and the cultural evolution of medicinal plant use

Human life depends on plant biodiversity and the ways in which plants are used are culturally determined. Whilst anthropologists have used phylogenetic comparative methods (PCMs) to gain an increasingly sophisticated understanding of the evolution of political, religious, social, and material culture, plant use has been almost entirely neglected. Medicinal plants are of special interest because of their role in maintaining people’s health across the world. PCMs in particular, and cultural evolutionary theory in general, provide a framework in which to study the diversity of medicinal plant applications cross-culturally, and to infer changes in plant use through time. These methods can be applied to single medicinal plants as well as the entire set of plants used by a culture for medicine, and they account for the non-independence of data when testing for floristic, cultural or other drivers of plant use. With cultural, biological, and linguistic diversity under threat, gaining a deeper and broader understanding of the variation of medicinal plant use through time and space is pressing

Plant DNA barcodes and assessment of phylogenetic community structure of a tropical mixed dipterocarp forest in Brunei Darussalam (Borneo)

DNA barcoding is a fast and reliable tool to assess and monitor biodiversity and, via community phylogenetics, to investigate ecological and evolutionary processes that may be responsible for the community structure of forests. In this study, DNA barcodes for the two widely used plastid coding regions rbcL and matK are used to contribute to identification of morphologically undetermined individuals, as well as to investigate phylogenetic structure of tree communities in 70 subplots (10 × 10m) of a 25-ha forest-dynamics plot in Brunei (Borneo, Southeast Asia). The combined matrix (rbcL + matK) comprised 555 haplotypes (from ≥154 genera, 68 families and 25 orders sensu APG, Angiosperm Phylogeny Group, 2016), making a substantial contribution to tree barcode sequences from Southeast Asia. Barcode sequences were used to reconstruct phylogenetic relationships using maximum likelihood, both with and without constraining the topology of taxonomic orders to match that proposed by the Angiosperm Phylogeny Group. A third phylogenetic tree was reconstructed using the program Phylomatic to investigate the influence of phylogenetic resolution on results. Detection of non-random patterns of community assembly was determined by net relatedness index (NRI) and nearest taxon index (NTI). In most cases, community assembly was either random or phylogenetically clustered, which likely indicates the importance to community structure of habitat filtering based on phylogenetically correlated traits in determining community structure. Different phylogenetic trees gave similar overall results, but the Phylomatic tree produced greater variation across plots for NRI and NTI values, presumably due to noise introduced by using an unresolved phylogenetic tree. Our results suggest that using a DNA barcode tree has benefits over the traditionally used Phylomatic approach by increasing precision and accuracy and allowing the incorporation of taxonomically unidentified individuals into analyses

Elaboration d’une table anthropométrique de caractéristiques inertielles de segments corporels par la méthode de Jensen : étude de faisabilité sur 100 sujets Béninois

Cette étude met en oeuvre l’utilisation de la méthode de Jensen pour élaborer une table anthropométrique de caractéristiques inertielles de segments corporels. Le matériel nécessaire à l’acquisition des données est réduit à deux appareils photos numériques standards, un pèse-personne, une toise et le logiciel Slicer Project. 100 sujets volontaires (hommes et femmes) âgés de 15 ans à 30 ans, obèses et non obèses ont participé à l’étude. Ils sont de nationalité béninoise, sans handicap apparent et sont répartis en quatre groupes de 25 sujets (hommes, femmes, obèses et non obèses). Les valeurs moyennes des paramètres d’étude obtenues par les méthodes de Jensen, de Winter et de volumétrie sont comparées entre elles par le test statistique de Student pour échantillons appariés. Les valeurs sont considérées significativement identiques au seuil 5%. Quels que soient le sexe et la catégorie d’obésité, les résultats montrent qu’il n’y a pas de différence significative relevée entre la masse corporelle mesurée, en comparaison à celle obtenue par slicer de Jensen ; en outre, les différences entre Jensen et Winter d’une part (par rapport aux masses des segments distaux) et puis Jensen et Volumétrie d’autre part (par rapport aux volumes des segments distaux) ne sont pas aussi significatives. La méthode présentée ici permet l’obtention rapide et aisée des caractéristiques géométriques et inertielles individualisées des segments corporels d’un sujet, de manière quasi-automatique.Mots clés : Modélisation, Mesures anthropométriques; méthode de Jensen.English AbstractThis study aims to develop, from Jensen's method a table of values of inertial body segments of 100 subjects. They are all Benin citizens, aged 15 to 30 and with no pathological volunteered who are participated in the study. There were divided into four groups of 25 (men, women, obese and no obese). The equipment required for data acquisition is reduced to two standard digital cameras cheap, scales, a meter and a logical Slicer project. A value average of study parameters obtain with Jensen, winter and volumetric are compared between them with the statistic test student. A value of p ˂ 0.05 was chosen as the significance threshold for all variables under study. With both of the sex and obese or no obese, the results showed that there is no different significant between a direct mass and mass esteemed with Jensen's method. Somewhere, the different between Jensen and winter on the one hand (comparison of mass segments distain); then between Jensen and volumetric on the other (comparison of volume segments distain) are not too significant. The method presented here allows obtaining quickly and easily individualized geometrical and inertial body segment of a subject, almost automatically.Keywords: Modeling, Anthropometry; method of Jensen

The magnetic properties of mixed spin-[Formula presented] anisotropic Heisenberg model in the Oguchi approximation

© 2022 Elsevier B.V.We have used the Oguchi approximation to study the effects of longitudinal crystal (D) and longitudinal external magnetic (h) fields on the mixed spin-[Formula presented] anisotropic Heisenberg model. The thermal variations of sublattice and total magnetizations are exploited in detail for given values of D, exchange anisotropy parameter (Δ) and coordination numbers z=3,4 and 6 when h=0.0. Thus, the phase diagrams are constructed on the planes of (D/J,kBT/J) and (Δ,kBT/J). In this case, it is found that the model presents either first- or second-order phase transitions as well as tricritical points. In the presence of magnetic field, the hysteresis loops of the model are also analyzed and it was found that the coercive field and remanent magnetization decrease as the temperature increases and increase as the crystal field or the exchange anisotropy increases