Se a história da Metafísica é marcada por grandes transformações e mesmo reivindicações de revoluções ou revisões radicais de seus conceitos, foi em torno da noção de substância que essas mudanças muitas vezes se estabeleceram. Esperamos esclarecer a leitoras e leitores quais podem ser as marcas características da substância e por que filósofas e filósofos disputam tanto essa definição. Para explicar essa divergência, oferecemos uma apresentação organizada historicamente, mas focada nos elementos conceituais em jogo. Com efeito, não se tratará aqui de fixar datas, obras, nomes; mas antes de elaborar certas perspectivas que permitam balizar o percurso do pensamento até chegar a esta nossa época da qual, de tão perto que estamos dela, ainda não podemos oferecer uma caracterização precisa. Se selecionar e fixar marcos históricos será sempre uma tarefa eminentemente polêmica, leitoras e leitores da presente coletânea certamente perceberão que, a julgar pelas referências aqui privilegiadas, restam poucas dúvidas quanto às principais etapas da trajetória do conceito.

The present study analyzed how the economic, social and human mobility factors were responsible for dissemination of Covid -19 in Brazil and the Legal Amazon region. Human mobility was analyzed by four dimensions according to the network's hierarchies of: migration, pendular mobility, airlift, hydro and road routes and healthcare system. Manaus, capital of Amazon, was the first diffuser pole of cases; this may be explained by absence of public lockdown policies and restriction of mobility by river routes and airport system. In the face of the worsening of the pandemic, between March to May 2020, the previous migratory pattern of the urban population was accentuated to inland Amazonian cities that spread the virus towards remote areas of the Amazon. In addition, there was a pendular migratory movement to Manaus, which is the only center in the region with highly complex hospitals; this fact led to a strong migratory movement of populations seeking medical assistance. The analysis on migration revealed a close relation of the spatiotemporal behavior of Covid-19 spread and the migration network to Manaus. There were significant correlations related to fluvial or waterway transportation axis along the Amazon River which is the dominant route of the region. These pathways have long distances to be covered from one pole to another and were additional factors for the spread of the pandemic during the period studied and have long travel times that can be an important factor for COVID-19 further dissemination. We conclude that the wide dissemination of COVID-19 cases across the Legal Amazon was the result of multifactorial causes that include social inequities, vulnerability, high rate of mobility and migration, information failure and administrative and social management of the crisis.

At the beach, death assemblages are constantly reworked by wind and waves. One of the various consequences of this shore dynamic is the constant burial and exhumation of the shells, making them inappropriate for epibionts. However, some gastropod shells collected in the death assemblages arranged on the foreshore of the coastal plain of south Brazil were hardly encrusted. Olivancillaria urceus corresponds to 48.8% of all encrusted taxa, suggesting that some shell species may play a more striking role than others as available bioclasts. Therefore, the research aims to discuss the taphonomic implications for epibionts and bioerosion in gastropod shells. Abandoned gastropod shells were collected on 27 sites along a 150 km coastal strip in southernmost Brazil. Epibionts and bioerosion traces were identified, and their frequency was calculated considering their abundance, which taxa they occurred in, and their settlement on the different parts of the shells. At least 13 of 21 taxa were colonized by epibionts, of which 97% were by bryozoans. Other epibionts recognized were serpulid tubes, bivalves, and balanids. Fifteen taxa were bioeroded, showing traces made by worms (cf. Caulostrepsis), bryozoans (cf. Pennatichnus), balanids (cf. Rogerella), bivalves (cf. Gastrochaenolites), and sponges (cf. Entobia). The results reached in this survey suggest that the bryozoans have an advantage over other epibionts at colonizing the gastropod shells.

The paleoecological evolution of a peat bog in the Campos region, Rio Grande do Sul State, Brazil, was determined based on an integrated study of stratigraphy, palynology, and geochronology. The peat bog is constituted of silty-clay material, with high levels of ash (residue on ignition) and organic matter content that was deposited on a sandy substrate. Palynological analysis show that grassland taxa dominated from the base of the core at the early deglacial (∼17.4 cal kyr B.P.) to the Present. Four pollen zones were identified: CCQ I Zone (3.20 m to 2.50 m), covering the deglaciation (Upper Pleistocene), corresponding to dry climate conditions; CCQ II Zone (2.50 m to 1.60 m, latest deglaciation and Early Holocene), associated with a slightly humid climate; CCQ III Zone (1.60 m to 0.50 m, mid to late Holocene), established under very humid climatic conditions; and CCQ IV Zone (0.50 m to 0.00 m, last ∼500 years), representative of a low-humidity period. The floristic composition of grassland communities observed throughout the drill core is very similar to that found in the region where the municipality of Cacequi is located, in which Poaceae, Asteraceae, Fabaceae, and Rubiaceae were identified as the most abundant families. Consequently, although in the last ∼17.4 cal kyr B.P. the humidity oscillated, the grassland vegetation remained predominant, although not being represented by the same families, as indicated by changes in the floristic composition among the four pollen zones. Palynological and geochronological data, when compared with other sectors of the Río de la Plata Grasslands, show a predominance of dry conditions over the studied interval. From the early deglacial until the Present, climatic fluctuations shaped the diversity of plant communities and affected the particularities of each sector of the Río de la Plata Grasslands, including the Campos region. High ash content was detected along the core, similar to what occurs with other peatlands already studied in Brazil. In the peat bog analyzed, Poaceae is the predominant family, being known as a major producer of biomineralized structures, which would explain the high ash content recorded.

The southern skies and tall mountains of Latin America have cultivated a long history of astronomy on the continent. Today, the continent hosts over 80 observatories that are collaborative research centres for the region and the world. But what about other areas of physics? These have benefited from a culture of collaboration, but there are still challenges in fully developing the potential of research on the continent, such as insufficient researchers or resources. In this Viewpoint, seven physicists discuss the varying research landscapes of different areas of physics across the continent.

Fjords are considered biodiversity hotspots and aquatic critical zones, being extremely sensitive to climate change due to close oceanic, terrestrial, and glacial interactions. These ecosystems have received a great deal of attention in research on current and future anthropic impacts. Despite this, there is no analog in the geological record that presents icehouse-greenhouse biological and climatic changes. Here we present an analog, through a detailed taphonomic survey of the Lontras Shale Lagerstätte (Itararé Group, Paraná Basin, Brazil), related to a climatic optimum of the end of the Late Paleozoic Ice Age (Late Pennsylvanian), in which a temperate outer paleofjord with a rich well-preserved biota was installed. In the monotone layers of black shale, we find subtle variations of the dominant skeletal type, rates of fragmentation and disarticulation, and other taphonomic aspects that define distinct taphofacies. Each of them is the result of distinct time-averaging related to mass mortality events, turbidity, and depositional hiatus periods at different scales and intensities, mixing the ecologic census with short-term and long-term within-habitat assemblages. In addition, the rich paleobiota was reconstructed with autochthonous and allochthonous benthic fauna, many marine nektonic organisms, and intense continental contribution of terrestrial bioclasts, that proliferated and were exceptionally preserved by the establishment of an anoxic temperate outer fjord. The taphofacies show an evolution in a high-frequency sequence within a highstand systems tract, linked to climatic improvement. Furthermore, taphonomic detailing can be used as a comparison of deep marine and deep lacustrine taphofacies, in addition to serving as an analog for the short-time scale biological, biogeochemical, climatic, and stratigraphic changes associated with the icehouse–greenhouse transition in the past, present, and future.