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

Measurement of vector boson production cross sections and their ratios using pp collisions at √s = 13.6 TeV with the ATLAS detector

Abstract available from publisher's website

Beam-induced backgrounds measured in the ATLAS detector during local gas injection into the LHC beam vacuum

Inelastic beam-gas collisions at the Large Hadron Collider (LHC), within a few hundred metres of the ATLAS experiment, are known to give the dominant contribution to beam backgrounds. These are monitored by ATLAS with a dedicated Beam Conditions Monitor (BCM) and with the rate of fake jets in the calorimeters. These two methods are complementary since the BCM probes backgrounds just around the beam pipe while fake jets are observed at radii of up to several metres. In order to quantify the correlation between the residual gas density in the LHC beam vacuum and the experimental backgrounds recorded by ATLAS, several dedicated tests were performed during LHC Run 2. Local pressure bumps, with a gas density several orders of magnitude higher than during normal operation, were introduced at different locations. The changes of beam-related backgrounds, seen in ATLAS, are correlated with the local pressure variation. In addition the rates of beam-gas events are estimated from the pressure measurements and pressure bump profiles obtained from calculations. Using these rates, the efficiency of the ATLAS beam background monitors to detect beam-gas events is derived as a function of distance from the interaction point. These efficiencies and characteristic distributions of fake jets from the beam backgrounds are found to be in good agreement with results of beam-gas simulations performed with theFluka Monte Carlo programme

Excision of sclerocorneal limbus in dogs and resulting clinical events: study of an experimental model

As conseqüências da completa remoção do epitélio do limbo esclerocorneano foram avaliadas, bem como o modelo utilizado para tal, em que se empregou o n-heptanol e a ceratectomia superficial. O n-heptanol e a ceratectomia associados possibilitaram a completa excisão das células-tronco. da destruição dessas células decorrem alterações tectônicas significativas factíveis para estudos dos transplantes de córnea.The consequences of complete removal of the sclerocorneal limbus epithelium were evaluated, as well as the model for such, in which n-heptanol and superficial keratectomy were used. The association of n-heptanol and keratectomy allowed a complete excision of stem cells. Moreover, the destruction of these cells led to significant tectonic alterations that could be employed as a feasible model for clinical experimentation of corneal transplantation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Sclerocorneal limbal stem cell autograft transplantation in dogs

Avaliaram-se os efeitos do transplante de células tronco autógenas do limbo esclerocórneo de cães, sobre lesões córneo-limbais. Empregaram-se 18 cães, distribuídos em dois grupos, GI e GII. Nos animais do GI (n=12), foram realizados transplantes de limbo, após 30 dias da destruição das células tronco-límbicas. Nos do GII (n=6), realizou-se apenas a destruição do limbo (controle). Aos 3, 7, 15, 30, 60 e 120 dias do transplante de limbo (GI) e aos 33, 37, 45, 60, 90 e 150 dias da destruição do limbo (GII), os olhos foram coletados por enucleação subconjuntival, para estudos em microscopia de luz. A destruição do limbo resultou em completa excisão das células tronco, com perda da transparência corneal. O transplante do limbo evitou a conjuntivalização na área em que foi realizado. Os animais do grupo-controle manifestaram conjuntivalização em 360º e vascularização corneal. Na anatomopatologia, em nenhum dos períodos foi possível distinguir o enxerto do epitélio corneal normal. As células caliciformes foram observadas nos animais do GII, nos períodos 33, 37, 60, 150 dias. No GI, apenas um cão manifestou células caliciformes de forma discreta, aos 60 dias do transplante. O transplante autógeno foi eficiente em possibilitar a melhoria da transparência córnea, sem intercorrências oculares.The effects of sclerocorneal limbal stem cell autograft transplantation in dogs with corneal wounds were studied. Eighteen dogs were divided in two groups (GI and GII). The animals of GI (n=12) underwent limbal transplantation 30 days after the destruction of limbal stem cells. The dogs of GII (n=6) only underwent destruction of stem cells (control group). Light microscopy examination of the right eye was performed on days 3, 7, 14, 30, 60, and 120 after limbal transplantation (GI), and on days 33, 37, 44, 60, 90, and 150 after limbal destruction (GII). Results showed a complete destruction of limbal stem cells with loss of corneal transparency. Limbal transplantation prevented conjunctivalization in grafted area. Corneal vascularization and a 360º corneal conjunctivalization were noted in the control dogs (GII). Corneal transparency was restored from day 60th after surgery. Histological examination did not distinguish the transition between the graft and the normal corneal epithelium at anytime. Goblet cells were found in control animals (GII) on 33, 37, 60, and 150 days, whereas a single grafted dog (GI) presented a few goblet cells on day 60th post-transplantation. Limbal autograft transplantation was effective in restoring corneal clarity with no development of ocular complications.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq