Correlates of elevational specialisation in Southeast Asian tropical birds

The understanding of elevational selectivity in extremely rich tropical biotas is critical to the study of accelerating human-mediated environmental changes (e.g., deforestation and global climate warming). This paper explores the characteristics of Southeast Asian birds that are altitudinal specialists (i.e., lowland specialists and montane specialists) by assessing the relative importance of various species traits (e.g., breeding phenology and clutch size) in determining the altitudinal specialisation of these tropical birds. After controlling for phylogeny, we found that habitat specificity, breeding phenology, and clutch size were significant correlates of lowland specialisation. The most parsimonious model predicting lowland specialisation included the first of these only. Breeding phenology was the significant phylogeny-independent correlate of montane specialisation. Thus, species were confined to altitudinal niches by different constraints. By analysing the altitudinal distribution of Southeast Asian birds, we provide insights on why altitudinal confinement exists in lowland and montane specialists. Understanding such constraints may be important for the conservation of tropical birds

Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes

Trade-level productivity measurement: Critical challenges and solutions

10.1061/(ASCE)CO.1943-7862.0000761Journal of Construction Engineering and Management13911-JCEM

Double deletions of glutathione S-transferase genes (GSTM1 and GSTT1) reduce the risk of early relapse in childhood B-lineage acute lymphoblastic leukaemia (ALL).

Annals of the Academy of Medicine, Singapore335 Supp

Investigation of magnetic properties and microwave characteristics of obliquely sputtered NiFe/MnIr bilayers

10.1063/1.4792496Journal of Applied Physics1137-JAPI

Note: Electrical detection and quantification of spin rectification effect enabled by shorted microstrip transmission line technique

10.1063/1.4865122Review of Scientific Instruments852-RSIN

Magnetization dynamics in permalloy films with stripe domains

10.1063/1.4817767Journal of Applied Physics1145-JAPI

Implications of climate change for Malaysian tropical montane bird communities discernible over a 14-years interval

Tropical montane ecosystems are vulnerable to multiple threats, and severe ecological impact on such systems has been documented. However, trends for local montane biodiversity are often varied. Such discrepancy underscores the need to parse the spatial and temporal dynamic of each habitat type within a montane landscape in terms of their species richness, species turnover rate, and relative abundance. We studied species richness and composition of two tropical montane bird communities at two localities in Peninsular Malaysia in 2002-03 and 2016-17. The habitat types sampled at each locality represent a disturbance gradient within a montane landscape. While the number of species generally increased along the disturbance gradient, all study sites (bar tea plantation) had the same or fewer species observed in 2016-17. At the community level observed from the two time periods, Fraser’s Hill – where development has been absent since 1920s – had a decrease in species richness; and a higher proportion of species with a decline in their relative abundance, compared to the more disturbed landscape in Cameron Highlands. Both the number of species lost and the number of species gained also varied considerably between the two communities. Our results suggest that climate change is a likely factor in negatively impacting the montane bird communities in Peninsular Malaysia, and highlight the need to monitor the temporal dynamic in the composition of local communities