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Recent studies indicate that the discriminatory power of the core DNA barcodes (rbcLa + matK) for land plants may have been overestimated since their performance have been tested only on few closely related species. In this study we focused mainly on how the addition of complementary barcodes (nrITS and trnH-psbA) to the core barcodes will affect the performance of the core barcodes in discriminating closely related species from family to section levels. In general, we found that the core barcodes performed poorly compared to the various combinations tested. Using multiple criteria, we finally advocated for the use of the core + trnH-psbA as potential DNA barcode for the family Combretaceae at least in southern Africa. Our results also indicate that the success of DNA barcoding in discriminating closely related species may be related to evolutionary and possibly the biogeographic histories of the taxonomic group tested.

Medicinal plants cover a broad range of taxa, which may be phylogenetically less related but morphologically very similar. Such morphological similarity between species may lead to misidentification and inappropriate use. Also the substitution of a medicinal plant by a cheaper alternative (e.g. other non-medicinal plant species), either due to misidentification, or deliberately to cheat consumers, is an issue of growing concern. In this study, we used DNA barcoding to identify commonly used medicinal plants in South Africa. Using the core plant barcodes, matK and rbcLa, obtained from processed and poorly conserved materials sold at the muthi traditional medicine market, we tested efficacy of the barcodes in species discrimination. Based on genetic divergence, PCR amplification efficiency and BLAST algorithm, we revealed varied discriminatory potentials for the DNA barcodes. In general, the barcodes exhibited high discriminatory power, indicating their effectiveness in verifying the identity of the most common plant species traded in South African medicinal markets. BLAST algorithm successfully matched 61% of the queries against a reference database, suggesting that most of the information supplied by sellers at traditional medicinal markets in South Africa is correct. Our findings reinforce the utility of DNA barcoding technique in limiting false identification that can harm public health.

This study seeks to formulate best practice indicators characterising the prepaid electricity meter market. This was undertaken by reviewing both developed and developing countries' experiences with the technology, conducting in‐depth interviews with key stakeholders, and applying the strength weaknesses opportunities threats analysis tool. The generated outcomes are used to formulate a set of best practice recommendations that can inform decisions on improving the acceptability rate of the technology in Soweto. We found that the introduction of the technology faces a number of challenges, broadly being its complete rejection by some communities. In particular, the inadequacy or absence of incentives, the absence of prepaid meter market tariffs and regulatory mechanisms are fundamental factors affecting acceptance levels and effectiveness of the technology in developing countries. The case of Soweto is unique in that it has a historical political basis that even led to some violent protests. To improve the acceptance level and increase the buy‐in of local communities in Soweto, we formulated a number of best practice recommendations including the need to factor in the programme design the historical context‐specificity of Soweto, its low‐income status, the need to put the communities at the centre of the programme and the implementation of incentive measures inspired from the developed world. [ABSTRACT FROM AUTHOR]

Al-based fluoroperovskites compounds AlMF3 (M = Cr, B) are investigated computationally and calculated their elastic, structural, optical, and electrical properties in this study utilising TB-MBJ potential (also GGA+U for AlCrF3) approximations, according to the Birch Murnaghan Equation curve and tolerance factor, these material are structurally cubic and stable. The IRelast algorithm is used to forecast elastic properties, and the outputs show that these compound are mechanically stable, anisotropic and ductile. AlBF3 has a metallic nature and overlapping states, while AlCrF3 have a narrow indirect band gap at (X-M) points of symmetry, with band gaps of 0.71 eV for AlCrF3 and zero eV for AlBF3. The partial and total density of states are being used to determine the influences of different basic states to the conduction and valence bands (TDOS & PDOS). Investigation of Optical properties shows that these compounds have low refractive index and high absorption coefficient, conductivity, reflective coefficient at high energy ranges. Owing to the indirect band gap, the applications of these compounds are deemed in conducting industries. Here we are using these compounds for first time and are examined using the computational method, which delivers a complete view into the different properties. [ABSTRACT FROM AUTHOR]

This work displays the structural, electronic, elastic, optical, and magnetic properties in spin-polarized configurations for cubic fluoroperovskite A B F 3 (A = Tl, B = Nb, V) compounds studied by density functional theory (DFT) by means of the Tran-Blaha-modified Becke-Johnson (TB-mBJ) approach. The ground state characteristics of these compounds, i.e., the lattice parameters a 0 , bulk modulus (B), and its pressure derivative B ′ are investigated. The structural properties depict that the selected compounds retain a cubic crystalline structure and have stable ground state energy. Electronic-band structures and DOS (density of states) in spin-polarized cases are studied which reports the semiconducting nature of both materials. The TDOS (total density of states) and PDOS (partial density of states) studies in both spin configurations show that the maximum contributions of states to the different bands is due to the B-site (p-states) atoms as well as F (p-states) atoms. Elastic properties including anisotropy factor (A), elastic constants, i.e., C11, C12, and C44, Poisson's ratio (υ), shear modulus and (G), Young's modulus (E) are computed. In terms of elastic properties, the higher (bulk modulus) "B" and ratio of "B/G" yield that these materials exhibit a ductile character. Magnetic properties indicate that both the compounds are ferromagnetic. In addition, investigations of the optical spectra including the real ( ε 1 ω ) and imaginary ( ε 2 ω ) component of the dielectric function, refractive index n ω , optical reflectivity R ω , optical conductivity σ ω , absorption coefficient α ω , energy loss function L ω , and electron extinction coefficient k ω are carried out which shows the transparent nature of T l V F 3 and T l N b F 3 . Based on the reported research work on these selected materials, their applications can be predicted in many modern electronic gadgets. [ABSTRACT FROM AUTHOR]

This paper explains our first-principle computational investigation regarding the structural, optical, elastic, and electrical characteristics of gallium-based GaMF3 (M = Be and Ge) perovskite-type (halide-perovskite) compounds. Our current computation is based on density functional theory (DFT) and is achieved with the help of the WIEN2k code. We used the Birch–Murnaghan equation for optimization; in both compounds, we found that both GaBeF3 and GaGeF3 compounds are structurally stable. For the computation of elastic characteristics, the IRelast package for calculating elastic constants (ECs) is utilized. These compounds are mechanically ductile, scratch-resistant, anisotropic, and mechanically stable, showing huge opposition to plastic strain. The modified Becke–Johnson (TB-mBJ) potential approximation method is used to calculate different physical characteristics and shows that GaGeF3 behaves as a metal, whereas the GaBeF3 compound is insulating in nature. The involvement of various electronic states in band structures is calculated using the theory of the density of states. The different optical properties of these compounds can be studied easily using their band gap energy. At high energy ranges, these substances demonstrate strong absorption. At low energies, the GaGeF3 compound is transparent, while the GaBeF3 compound is opaque to incoming photons. Investigation of the optical characteristics has led us to the conclusion that both GaGeF3 and GaBeF3 compounds can be used for high-frequency ultraviolet device applications. This computational work is considered to be the first time that we can study these compounds, which to our knowledge have not previously been experimentally validated. [ABSTRACT FROM AUTHOR]

South Africa is one of the most vulnerable countries to the invasion of alien species (Bezeng et al., [4]; Bezeng, Davies, Yessoufou, Maurin, & Van der Bank, [5]). METHODS Categories of alien mammals and data collection The same categories of alien mammals used in Yessoufou et al. ([43]) are adopted in this study. The correlation of ED with invasion intensity is an indication that invasion of alien mammals in South Africa may have been phylogenetically mediated (Yessoufou et al., [43]) as predicted implicitly in Darwin naturalisation hypothesis (Daehler, [11]). [Extracted from the article]

• Our biogeographic analysis suggests that the genus Encephalartos may have diverged around 9 Ma from southern Africa and then colonized the region through dispersal. • The east-central-west African clade might have diverged from the southern African clade through vicariance. • The eastern rift system in eastern Africa and the West African Dahomey Gap may act as geographical barriers driving the vicariance observed. • Although there was rapid species accumulation 2.6 Ma, the shift in diversification may not be as dramatic as initially thought. Of the 10 known genera of cycads, the genus Encephalartos is one of the two endemic genera to Africa. Although a number of studies have explored the taxonomic relationships within the genus as well as its diversification history, we still have limited understanding of its historical biogeography. In the present study, using five gene markers, we first reconstructed a complete phylogeny of the genus and its historical biogeography based on S-DIVA model. We then fitted the COMET model to the phylogeny to test for significant shifts in evolutionary events that may have driven the current diversity in the genus. Overall, our phylogeny is well supported and reveals two major clades following species geographic origins, one southern African clade and one east-central-west African clade. Our biogeographic analysis suggests that the genus may have diverged around 9 Ma from southern Africa (100% probability) and then colonized the region through dispersal. Although the origin of the east-central-west African clade is uncertain (50% probability), the clade may have diverged from the southern African clade through vicariance. We suggest that the eastern rift system in eastern Africa and the west African Dahomey Gap – a dry corridor that breaks pan-African tropical rainforest into different blocks – are geographical barriers limiting dispersal into the rest of the continent whilst, at the same time, promoting the vicariance signature observed. Although most species accumulated in the last 2.6 My, there were no significant shifts in any of the evolutionary events, suggesting that an overall constant-rate diversification model is best suited for the genus and that the rapid species accumulation during the Pliocene–Pleistocene transition may not be as dramatic as initially thought. [ABSTRACT FROM AUTHOR]