Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, 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 organism 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 neglected 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 lost

Microwave-activated carbons from tucumã (<i>Astrocaryum aculeatum</i>) seed for efficient removal of 2-nitrophenol from aqueous solutions

<p>Activated carbons (ACs) prepared from tucumã seed (<i>Astrocaryum aculeatum</i>) were used for 2-nitrophenol removal from aqueous solutions. The ACs were characterized by elemental analysis, FTIR, <i>N</i>₂ adsorption/desorption isotherms, TGA, hydrophobicity/hydrophilicity balance, and total of acidic and basic groups. The ACs showed to have hydrophilic surfaces and they presented high specific surface areas (up to 1318 m² g⁻¹). In batch optimization studies, maximum removal was obtained at pH 7, contact time of 30 min, adsorbent dosage 1.5 gL⁻¹ and temperature of 50°C. The general-order kinetic model and Liu isotherm model best fit the kinetic and equilibrium adsorption data with a maximum adsorption capacity of 1382 mg g⁻¹ at 50°C. Effect of temperature and thermodynamic studies revealed that the adsorption processes of 2-nitrophenol onto ACs are dependent on temperature and are exothermic and spontaneous, respectively. About the applicability of the ACs for treating simulated effluents, the tucumã seed-activated carbon showed an excellent outcome in the treatment of simulated effluents, evidencing its high efficiency for phenolic compound adsorption. Tucumã seed-ACs showed to be cost effective and highly efficient adsorbents for efficient removal of 2-nitrophenol from aqueous solutions.</p

Aspectos morfológicos, morfométricos e ultraestruturais do baço de ratos após o clampeamento total do pedículo hepático Morphologic, morphometric, and ultrastructural aspects of the spleen of rats after hepatic pedicle total clamping

Avaliaram-se as alterações morfológicas, morfométricas e ultraestruturais que ocorreram no baço devido à isquemia produzida pelo clampeamento total do pedículo hepático. Para tanto, foram utilizados 40 ratos machos, distribuídos em quatro grupos de 10 animais. O grupo-controle (C) não foi submetido à isquemia, e os grupos tratados (E1, E2e E3) foram submetidos ao clampeamento por 10, 20 e 30 minutos, respectivamente. Fragmentos do baço foram retirados e analisados histologicamente pela microscopia de luz (hematoxilina-eosina, ferrocianeto-férrico) e pela microscopia eletrônica de transmissão. Os resultados demonstraram que 10 minutos de clampeamento do pedículo hepático são suficientes para apresentar sinais de congestão esplênica e 20 e 30 minutos promovem intensa digestão de hemácias pelos macrófagos, com presença de grânulos de ferro (hemossiderina) no parênquima esplênico.<br>The macro and microscopic alterations that occurred in the spleen during an ischemia produced by the hepatic pedicle total clamping were studied. Forty male rats were distributed in four groups of 10 animals each. The control group (C) was not submitted to ischemia and the treated groups (E1, E2, and E3) were submitted to the clamping during 10, 20, and 30 minutes, respectively. Spleen fragments were collected and histologically analyzed by the light microscopy (eosin-hematoxilin and ferric ferrocyanide) and by the transmission electron microscopy. The results showed that 10 minutes of hepatic pedicle total clamping was enough produce signs of splenic congestion and 20 and 30 minutes promoted intense red bood cels digestion by the macrophages with the presence of iron granules (hemosiderin) in the splenic parenchyma