Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Plate-like cell growth during directional solidification of a Zn–20wt%Sn high-temperature lead-free solder alloy

Although Zn–Sn alloys have suitable features for high temperature solders, as for example the absence of intermetallic compounds (IMCs) and relatively high melting temperatures, the control of the scale of the microstructure by adequate pre-programming of the solidification thermal parameters remains still a task to be accomplished. The present study focuses on the interrelation among hardness, microstructure features/segregation and solidification thermal parameters. An upward directional transient solidification apparatus was used in order to permit samples along a range of cooling rates to be obtained for such evaluation. The entire Zn–20wt%Sn alloy casting is characterized by a two-phase alternated structure, which resembles the morphology of a lamellar eutectic. Experimental growth laws having −1/2 and −1/4 exponents are proposed relating the interphase spacing to the growth rate and the cooling rate, respectively. The morphology and size of the Zn-rich plate-like cells, as well as the macrosegregation pattern are shown to affect the hardness1822936CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPNão tem2012/08494-