Lim, Norman (Norman T-Lon)

This study was part of a larger project to improve learning of undergraduate chemistry in Singapore through the use of self-authored three-tier multiple-choice questions (3TMCQs) and the giving/receiving of peer feedback. Specifically, we examined the quality of written feedback based on the classification by Hattie and Timperley (2007) that year 2 to 4 learners (N=31) gave each other on responses in their 3TMCQs (N=466 administered). It was found that the most common type of voluntary feedback given by test-makers was task (& self), followed by process (& self), self alone, and lastly regulation (& self) levels over seven chemistry courses. In addition, question type (based on revised Bloom’s Taxonomy) had a marginal effect on the quality of feedback received; instead, items answered incorrectly garnered higher quality feedback and were four times more important than the cognitive level of questions. Feedback quality given by more experienced students was also no better than those given by less experienced ones. While there is growing evidence supporting the self-authoring of questions and giving/receiving peer feedback to enhance learning at undergraduate levels, further research is warranted into the types of peer feedback that learners may receive when attempting different question formats.

We report the first chromosome-length genome assemblies for three species in the mammalian order Pholidota: the white-bellied, Chinese, and Sunda pangolins. Surprisingly, we observe extraordinary karyotypic plasticity within this order and, in female white-bellied pangolins, the largest number of chromosomes reported in a Laurasiatherian mammal: 2n = 114. We perform the first karyotype analysis of an African pangolin and report a Y-autosome fusion in white-bellied pangolins, resulting in 2n = 113 for males. We employ a novel strategy to confirm the fusion and identify the autosome involved by finding the pseudoautosomal region (PAR) in the female genome assembly and analyzing the 3D contact frequency between PAR sequences and the rest of the genome in male and female white-bellied pangolins. Analyses of genetic variability show that white-bellied pangolins have intermediate levels of genome-wide heterozygosity relative to Chinese and Sunda pangolins, consistent with two moderate declines of historical effective population size. Our results reveal a remarkable feature of pangolin genome biology and highlight the need for further studies of these unique and endangered mammals.

Scavenging is a common phenomenon, particularly amongst carnivorous vertebrates. By consuming carrion, vertebrate scavengers reduce resource availability for both pathogenic bacteria and their insect vectors. We investigated the ability of wild vertebrate scavengers to control agents of human diarrheal diseases (specifically Salmonella spp. and Shiga toxin- producing Escherichia coli [STEC]) in oil palm plantations in Sabah (East Malaysia), and the existence of spillover effect whereby additional vertebrate scavengers from adjacent forest patches result in greater disease control in plantation sections near these forest edges. Experimental carcasses were removed by common scavengers (Varanus salvator, Canis lupus familiaris, and Viverra tangalunga) at different time points, and this determined the length of time that the carcasses persisted in the environment. The amount of pathogenic bacteria on the surfaces of filth flies collected above the experimental carcasses was positively correlated to the duration of carcass persistence, and reduction in pathogenic bacterial abundances was largely due to carcass consumption by these vertebrate scavengers. Instead of a predicted positive spillover effect (greater scavenger activity near forest edges, hence reduced pathogen abundance), we detected a weak inverse spillover effect in which STEC counts were marginally higher in plantation sections near forest patches, and human hunting along the forest-plantation boundaries could explain this. We propose that making oil palm plantations scavenger- friendly could yield great human health benefits for the millions of workers employed in this rapidly-expanding industry, without drastically changing current management practices.

1. Connectivity modelling tools are important for developing mitigation strategies to alleviate negative impacts on animal movement caused by road networks. Arboreal gliding mammals are especially vulnerable to road widening as they are unable to cross gaps beyond their gliding capacity. However, there are limitations of conventional raster-based modelling techniques when applied on this group.
2.We developed and applied a new model that quantifies the changes in connectivity for an arboreal gliding species, the Sunda colugo, in Singapore using information on species-specific glide performance through a vector-based approach. We also incorporated a genetic algorithm to determine optimal locations for sets of glide poles that could be installed to improve connectivity.
3. Expectedly, connectivity was heavily impacted by the road widening works, with a 93.3% decrease in the total number of feasible glide paths connecting roadside trees.
4. Nine glide poles installed during the construction phase of the project were initially uninformed by the connectivity model and they provided 26 additional connections only. Comparatively, the top nine pole locations identified through the genetic algorithm provided 247 additional connections, almost 10 times more than the amount supplied by the initial nine glide pole locations determined through qualitative methods.
5. The multi-objective capacity of the genetic algorithm also reduced large connectivity gaps post-development, with simulated glide poles increasing the percentage of pixels covered with connectivity from 16.1% to 27.7%.
6. Synthesis and applications. Our model fills a knowledge gap in connectivity modelling for arboreal gliding mammals whose movements are affected by varying habitat alterations. We demonstrated that locations of mitigation structures greatly influence the success of mitigation efforts and the locations can be optimised by incorporating the glide performance of the species into the genetic algorithm. Given limited conservation resources, this approach would benefit managers in formulating cost-effective efforts for arboreal gliding mammals.