Optimized Design of Distributed Quasi-Cyclic LDPC Coded Spatial Modulation.

We propose a distributed quasi-cyclic low-density parity-check (QC-LDPC) coded spatial modulation (D-QC-LDPCC-SM) scheme with source, relay and destination nodes. At the source and relay, two distinct QC-LDPC codes are used. The relay chooses partial source information bits for further encoding, and a distributed code corresponding to each selection is generated at the destination. To construct the best code, the optimal information bit selection algorithm by exhaustive search in the relay is proposed. However, the exhaustive-based search algorithm has large complexity for QC-LDPC codes with long block length. Then, we develop another low-complexity information bit selection algorithm by partial search. Moreover, the iterative decoding algorithm based on the three-layer Tanner graph is proposed at the destination to carry out joint decoding for the received signal. The recently developed polar-coded cooperative SM (PCC-SM) scheme does not adopt a better encoding method at the relay, which motivates us to compare it with the proposed D-QC-LDPCC-SM scheme. Simulations exhibit that the proposed exhaustive-based and partial-based search algorithms outperform the random selection approach by 1 and 1.2 dB, respectively. Because the proposed D-QC-LDPCC-SM system uses the optimized algorithm to select the information bits for further encoding, it outperforms the PCC-SM scheme by 3.1 dB.

Chemical and antioxidant characterization of Dovyalis caffra and Dovyalis abyssinica fruits in Kenya.

This study aimed at chemical characterization of Dovyalis caffra (Hook.f. & Harv.) Sim. and Dovyalis abyssinica (A. Rich.) Warb. fruits from Kinamba Town (KT) in Laikipia county and Gitoro Forest (GF) in Meru county of Kenya. All analysed fresh fruit samples had low pH values averaging at 2.67. Other tests showed D. abyssinica-GF to be significantly inferior to D. caffra-GF and D. caffra-KT in terms of TSS, TSS:TTA ratio, and ascorbic acid content. Based on these parameters, D. caffra-KT presents itself with a higher potential for direct consumption as compared to D. caffra-GF. Proximate analysis of dried fruit pulps demonstrated D. abyssinica-GF to be significantly higher in ash content and significantly lower in protein and fat contents compared to the other two samples. There were insignificant difference in the fibre and carbohydrate contents of all the fruit samples. In phytochemical analysis, D. caffra-GF recorded the highest total polyphenol content of 1845 mg Gallic acid equivalent (GAE)/100 g while D. abyssinica-GF reported the lowest figure of 1128 mg GAE/100 g. Flavonoid and simple phenols fractions were in the range of 18.15-26.85% and 73.15-81.85% respectively in all fruit samples. As for antioxidant activity, D. caffra-GF recorded significantly high scores in both DPPH and CUPRAC assays, and D. abyssinica-GF the lowest. The range of DPPH and CUPRAC scores for all samples was 1995-4993 mg l-ascorbic acid/100 g and 1384-2303 mg l-ascorbic acid/100 g respectively. The current study presents the nutritional and health potential of D. caffra and D. abyssinica fruits. This forms a good basis for future adoption and exploitation of these fruits.

Optimized Distributed Generalized Reed-Solomon Coding with Space-Time Block Coded Spatial Modulation.

We present a well-known generalized Reed-Solomon (GRS) code incorporated with space-time block coded spatial modulation (STBC-SM) for wireless networks, which is capable of enjoying coded cooperation between the source and the relay. In the proposed distributed GRS-coded STBC-SM (DGRSC-STBC-SM) scheme, the source and relay nodes use distinct GRS codes. At the relay, we employ the concept of information selection to choose the message symbols from the source for further encoding. Thus, the codewords jointly constructed by the source and relay are generated at the destination. For achieving the best codeword set at the destination, we propose an optimal algorithm at the relay to select partial symbols from the source. To reduce the computational complexity, we propose a more practical algorithm with low complexity. Monte Carlo simulation results show that the proposed scheme using the low-complexity algorithm can achieve near-optimal error performance. Furthermore, our proposed scheme provides better error performance than its corresponding coded non-cooperative counterpart and the existing Reed-Solomon coded cooperative SM (RSCC-SM) scheme under identical conditions.

Harnessing microbiome and probiotic research in sub-Saharan Africa: recommendations from an African workshop.

To augment capacity-building for microbiome and probiotic research in Africa, a workshop was held in Nairobi, Kenya, at which researchers discussed human, animal, insect, and agricultural microbiome and probiotics/prebiotics topics. Five recommendations were made to promote future basic and translational research that benefits Africans.