261 research outputs found

    A nonet of novel species of Monanthotaxis (Annonaceae) from around Africa

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    As part of an ongoing revision of the genus Monanthotaxis Baill. (Annonaceae), nine new species are described and one variety is reinstated to species rank. Two new species from West Africa (Monanthotaxis aquila P.H. Hoekstra, sp. nov. and Monanthotaxis atewensis P.H. Hoekstra, sp. nov.), four new species from Central Africa (Monanthotaxis couvreurii P.H. Hoekstra, sp. nov., Monanthotaxis latistamina P.H. Hoekstra, sp. nov., Monanthotaxis tripetala P.H. Hoekstra, sp. nov. and Monanthotaxis zenkeri P.H. Hoekstra, sp. nov.), one new species from Tanzania (Monanthotaxis filipes P.H. Hoekstra, sp. nov.), one new species from the area around Maputo (Monanthotaxis maputensis P.H. Hoekstra, sp. nov.), one new species from the Comoro Islands (Monanthotaxis komorensis P.H. Hoekstra, sp. nov.) and Monanthotaxis klainei (Engl.) Verdc. var. angustifolia (Boutique) Verdc. is raised to species level leading to the replacement name Monanthotaxis atopostema P.H. Hoekstra, nom. nov. (not Monanthotaxis angustifolia (Exell) Verdc.). Complete descriptions, comparisons with related species, ecological information and IUCN conservation assessments are given for the new species. Five species were classified as critical endangered, two species as endangered, one as vulnerable and one as least concern, warranting the need of further collecting and studying those species

    A new species of Monanthotaxis from Gabon with a unique inflorescence type for Annonaceae

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    Monanthotaxis Baillon (1890: 878) currently consists of 56 species (Rainer & Chatrou 2006) confined to tropical Africa and Madagascar and is the second most species-rich genus of Annonaceae in Africa after Uvaria Linnaeus (1753: 536). Both genera belong to the tribe Uvarieae Hooker & Thomson (1855: 91, 92). Circumscription of this tribe has recently been modified to comply with the principle of monophyly, and it now almost exclusively consists of climbing species, all from the Old World tropics (Chatrou et al. 2012). Generic circumscription within Uvarieae has been in disarray for considerable time. Delimitation of Uvaria and related genera has recently been modified based on phylogenetic relationships (Zhou et al. 2010, Zhou et al. 2009). Monanthotaxis was monophyletic in Wang et al. (2012), based on a limited sampling of seven species. Subsequent study with increased sampling (Hoekstra, unpub.) has revealed that the African species of Friesodielsia van Steenis (1948: 458) and Exellia Boutique (1951b: 117) are nested in Monanthotaxis. Whatever the solution and taxonomic consequences, the name Monanthotaxis with the type Monanthotaxis congoensis Baillon (1890: 879) will be retained as it is the oldest valid generic name. Along with phylogenetic analysis, we are conducting a taxonomic revision. The last revision of Monanthotaxis and allied genera was published over a century ago by Engler & Diels (1901). Since then, only contributions to local floras have been published (e.g. Boutique 1951a, Le Thomas 1969, Robson 1960, Verdcourt 1971a). While studying the material of Monanthotaxis, we encountered a remarkable new species, which differs from all other species of Annonaceae in its large and lax panicle-like inflorescence. Panicle-like inflorescences are rare in Annonaceae, and those that have been recorded are either congested, as in e.g. Unonopsis and Guatteria (Erkens et al. 2008, Maas et al. 2007), or with only a few flowers, as in Monanthotaxis le-testui Pellegrin (1950: 75). This new species is probably closely related to M. congoensis since they share several characters. Verdcourt (1971b) divided the genus in three subgenera and five sections. In his classification, this new species would join M. congoensis in the typical section Monanthotaxis, which is easily distinguished by having flowers with the four to six petals in a single whorl and less than 17 stamens. Because it is so similar to M. congoensis, our new species will almost certainly be classified within Monanthotaxis, and we decided to publish it before a new generic classification has been completed

    Minimal Semantics for Action Specifications in First-order Dynamic Logic

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    In this paper we investigate minimal semantics for First Order Dynamic Logic formulas. The goal is to be able to write action specifications in a declarative pre/post-condition style. The declarative specification of actions comes with some well known problems: the frame problem, the qualification problem and the ramification problem. We incorporate the assumptions that are inherent to both the frame and qualification problem into the semantics of Dynamic Logic by defining orderings over Dynamic Logic models. These orderings allow us to identify for each declarative Dynamic Logic action specification a unique intended model. This unique model represents the system that must be associated with the specification given the prefential semantics that is defined by the orderings

    Dietary Diversity in Cambodian Garment Workers: The Role of Free Lunch Provision

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    The objective of this paper is to compare food consumption by Cambodian garment workers with and without access to a free model lunch provision through a factory-based canteen. Data from an exploratory randomised controlled trial were analysed. In total, 223 female Cambodian garment workers were allocated to an intervention arm (six-month lunch provision) or a control arm. Dietary intake on workdays was assessed by qualitative 24-h recalls at baseline and twice at follow-ups during the period of lunch provision using the Food and Agricultural Organization (FAO) guideline on assessing women´s dietary diversity. In total, 158 participants provided complete data on the dietary intake over workdays at all interviews. Lunch provision resulted in a more frequent consumption of dark green leafy vegetables (DGLV), vitamin A-rich fruits, other fruits, and oils and fats during lunch breaks. In contrast, flesh meats, legumes, nuts and seeds, as well as sweets, were eaten at a lower frequency. Except for a higher consumption rate of vitamin A-rich fruits and a lower intake frequency of sweets, lunch provision had a less clear impact on total 24-h intake from different food groups and was not associated with a higher women´s dietary diversity score (WDDS). A more gap-oriented design of the lunch sets taking into account underutilised foods and the nutritional status of the workers is recommended

    Investigating the usability and utility of tangible modelling of socio-technical architectures

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    Socio-technical models are models that represent social as well as technical elements of the modeling subject, where the technical part consists of both physical and digital elements. Examples are enterprise models and models of the target of assessment used in risk assessment. Constructing and validating these models often implies a challenging task of extracting and integrating information from a multitude of stakeholders which are rarely modelling experts and don’t usually have the time or desire to engage in modelling activities.\ud We investigate a promising approach to overcome this challenge by using physical tokens to represent the model. We call the resulting models tangible models.\ud In this paper we illustrate this idea by creating a tangible representations of a socio-technical modelling language used in Risk Assessment and provide an initial validation of the relative usability and utility of tangible versus abstract modelling by an experiment and a focus group, respectively. We discuss possible psychological and social mechanisms that could explain the enhanced usability and utility of tangible modelling approaches for domain experts. Finally, we discuss the generalizability of this approach to other languages and modelling purposes

    Bioquality Hotspots in the Tropical African Flora.

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    Identifying areas of high biodiversity is an established way to prioritize areas for conservation [1-3], but global approaches have been criticized for failing to render global biodiversity value at a scale suitable for local management [4-6]. We assembled 3.1 million species distribution records for 40,401 vascular plant species of tropical Africa from sources including plot data, herbarium databases, checklists, and the Global Biodiversity Information Facility (GBIF) and cleaned the records for geographic accuracy and taxonomic consistency. We summarized the global ranges of tropical African plant species into four weighted categories of global rarity called Stars. We applied the Star weights to summaries of species distribution data at fine resolutions to map the bioquality (range-restricted global endemism) of areas [7]. We generated confidence intervals around bioquality scores to account for the remaining uncertainty in the species inventory. We confirm the broad significance of the Horn of Africa, Guinean forests, coastal forests of East Africa, and Afromontane regions for plant biodiversity but also reveal the variation in bioquality within these broad regions and others, particularly at local scales. Our framework offers practitioners a quantitative, scalable, and replicable approach for measuring the irreplaceability of particular local areas for global biodiversity conservation and comparing those areas within their global and regional context

    Creatine kinase B deficient neurons exhibit an increased fraction of motile mitochondria

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    Contains fulltext : 69450.pdf ( ) (Open Access)BACKGROUND: Neurons require an elaborate system of intracellular transport to distribute cargo throughout axonal and dendritic projections. Active anterograde and retrograde transport of mitochondria serves in local energy distribution, but at the same time also requires input of ATP. Here we studied whether brain-type creatine kinase (CK-B), a key enzyme for high-energy phosphoryl transfer between ATP and CrP in brain, has an intermediary role in the reciprocal coordination between mitochondrial motility and energy distribution. Therefore, we analysed the impact of brain-type creatine kinase (CK-B) deficiency on transport activity and velocity of mitochondria in primary murine neurons and made a comparison to the fate of amyloid precursor protein (APP) cargo in these cells, using live cell imaging. RESULTS: Comparison of average and maximum transport velocities and global transport activity showed that CK-B deficiency had no effect on speed of movement of mitochondria or APP cargo, but that the fraction of motile mitochondria was significantly increased by 36% in neurons derived from CK-B knockout mice. The percentage of motile APP vesicles was not altered. CONCLUSION: CK-B activity does not directly couple to motor protein activity but cells without the enzyme increase the number of motile mitochondria, possibly as an adaptational strategy aimed to enhance mitochondrial distribution versatility in order to compensate for loss of efficiency in the cellular network for ATP distribution

    Little ecological divergence associated with speciation in two African rain forest tree genera

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    <p>Abstract</p> <p>Background</p> <p>The tropical rain forests (TRF) of Africa are the second largest block of this biome after the Amazon and exhibit high levels of plant endemism and diversity. Two main hypotheses have been advanced to explain speciation processes that have led to this high level of biodiversity: allopatric speciation linked to geographic isolation and ecological speciation linked to ecological gradients. Both these hypotheses rely on ecology: in the former conservation of ecological niches through time is implied, while in the latter adaptation via selection to alternative ecological niches would be a prerequisite. Here, we investigate the role of ecology in explaining present day species diversity in African TRF using a species level phylogeny and ecological niche modeling of two predominantly restricted TRF tree genera, <it>Isolona </it>and <it>Monodora </it>(Annonaceae). Both these genera, with 20 and 14 species, respectively, are widely distributed in African TRFs, with a few species occurring in slightly less humid regions such as in East Africa.</p> <p>Results</p> <p>A total of 11 sister species pairs were identified most of them occurring in allopatry or with little geographical overlap. Our results provide a mixed answer on the role of ecology in speciation. Although no sister species have identical niches, just under half of the tests suggest that sister species do have more similar niches than expected by chance. PCA analyses also support little ecological differences between sister species. Most speciation events within both genera predate the Pleistocene, occurring during the Late Miocene and Pliocene periods.</p> <p>Conclusions</p> <p>Ecology is almost always involved in speciation, however, it would seem to have had a little role in species generation within <it>Isolona </it>and <it>Monodora </it>at the scale analyzed here. This is consistent with the geographical speciation model for TRF diversification. These results contrast to other studies for non-TRF plant species where ecological speciation was found to be an important factor of diversification. The Pliocene period appears to be a vital time in the generation of African TRF diversity, whereas Pleistocene climatic fluctuations have had a smaller role on speciation than previously thought.</p> <p>Ecological niche modeling, species level phylogeny, ecological speciation, African tropics, <it>Isolona</it>, <it>Monodora</it>, Annonaceae</p
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