Exploring Network Analysis for Urban Planning and Disaster Risk Reduction in Informal Settlements: Cases From Honduras, Jamaica, and Peru

The work explores the use of street network analysis on informal settlements and discusses the potential and limitations of this methodology to advance disaster risk reduction and urban resilience. The urban network analysis tool is used to conduct graph analysis measures on street networks in three informal settlements in the LAC region: Portmore, Jamaica; Tegucigalpa, Honduras; and Lima, Peru. Authors incorporate risk variables identified by these communities and combine them with prospective scenarios in which street networks are strategically intervened to improve performance. Authors also compute one graph index named Reach centrality. Results are presented spatially through thematic maps, and statistically by plotting cumulative distributions. Findings show that centrality measures of settlements' networks helped identify key nodes or roads that may be critical for people's daily life after disasters, and strategic to improve accessibility. The proposed methodology shows potential to inform decisions on urban planning and disaster risk reduction

Branched-chain amino acids in metabolic signalling and insulin resistance

Branched-chain amino acids (BCAAs) are important nutrient signals that have direct and indirect effects. Frequently, BCAAs have been reported to mediate antiobesity effects, especially in rodent models. However, circulating levels of BCAAs tend to be increased in individuals with obesity and are associated with worse metabolic health and future insulin resistance or type 2 diabetes mellitus (T2DM). A hypothesized mechanism linking increased levels of BCAAs and T2DM involves leucine-mediated activation of the mammalian target of rapamycin complex 1 (mTORC1), which results in uncoupling of insulin signalling at an early stage. A BCAA dysmetabolism model proposes that the accumulation of mitotoxic metabolites (and not BCAAs per se) promotes β-cell mitochondrial dysfunction, stress signalling and apoptosis associated with T2DM. Alternatively, insulin resistance might promote aminoacidaemia by increasing the protein degradation that insulin normally suppresses, and/or by eliciting an impairment of efficient BCAA oxidative metabolism in some tissues. Whether and how impaired BCAA metabolism might occur in obesity is discussed in this Review. Research on the role of individual and model-dependent differences in BCAA metabolism is needed, as several genes (BCKDHA, PPM1K, IVD and KLF15) have been designated as candidate genes for obesity and/or T2DM in humans, and distinct phenotypes of tissue-specific branched chain ketoacid dehydrogenase complex activity have been detected in animal models of obesity and T2DM