Divergence and dispersion of global eddy propagation from satellite altimetry

It is well understood that isolated eddies are presumed to propagate westward intrinsically at the speed of the annual baroclinic Rossby wave. This classic description, however, is known to be frequently violated in both propagation speed and its direction in the real ocean. Here, we present a systematic analysis on the divergence of eddy propagation direction (i.e., global pattern of departure from due west) and dispersion of eddy propagation speed (i.e., zonal pattern of departure from Rossby wave phase speed). Our main findings include the following: 1) A global climatological phase map (the first of its kind to our knowledge) indicating localized direction of most likely eddy propagation has been derived from twenty-eight years (1993-2020) of satellite altimetry, leading to a leaf-like full-angle pattern in its overall divergence. 2) A meridional deflection map of eddy motion is created with prominent equatorward/poleward deflecting zones identified, revealing that it is more geographically correlated rather than polarity determined as previously thought (i.e., poleward for cyclonic eddies and equatorward for anticyclonic ones). 3) The eddy-Rossby wave relationship has a duality nature (waves riding by eddies) in five subtropical bands centered around 27°N and 26°S in the two hemispheres, outside which their relationship has a dispersive nature with dominant waves (eddies) propagating faster in the tropical (extratropical) oceans. Current, wind and topographic effects are major external forcings responsible for the observed divergence and dispersion of eddy propagations. These results are expected to make a significant contribution to eddy trajectory prediction using physically based and/or data-driven models.

Cancer cell migration on straight, wavy, loop and grid microfibre patterns

Cell migration plays an important role in physiological and pathological processes where the fibrillar morphology of extracellular matrices (ECM) could regulate the migration dynamics. To mimic the morphological characteristics of fibrillar matrix structures, low-voltage continuous electrospinning was adapted to construct straight, wavy, looped and gridded fibre patterns made of polystyrene (of fibre diameter ca. 3 μm). Cells were free to explore their different shapes in response to the directly-adhered fibre, as well as to the neighbouring patterns. For all the patterns studied, analysing cellular migration dynamics of MDA-MB-231 (a highly migratory breast cancer cell line) demonstrated two interesting findings: first, although cells dynamically adjust their shapes and migration trajectories in response to different fibrillar environments, their average step speed is minimally affected by the fibre global pattern; secondly, a switch in behaviour was observed when the pattern features approach the upper limit of the cell body’s minor axis, reflecting that cells’ ability to divert from an existing fibre track is limited by the size along the cell body’s minor axis. It is therefore concluded that the upper limit of cell body’s minor axis might act as a guide for the design of microfibre patterns for different purposes of cell migration.

Global Perspective of COVID-19 Vaccine Nationalism

This study aimed to explore the global perspective of the association between GDP of various countries and progress of COVID-19 vaccinations; to explore how the global pattern holds in the continents, and investigate the spatial distribution pattern of COVID-19 vaccination progress for all countries. We have used consolidated data on COVID-19 vaccination and GDP from Our World in Data, an open-access data source. Data analysis and visualization were performed in R-Studio. There was a strong linear association between per capita income and the proportion of people vaccinated in countries with one million or more populations. GDP per capita accounts for a 50% variation in the vaccination rate across the nations. Our assessments revealed that the global pattern holds in every continent. Rich European and North-American countries are most protected against COVID-19. Less developed African countries barely initiated the vaccination program. There is a significant disparity among Asian countries. The security of wealthier nations (vac-cinated their citizens) cannot be guaranteed unless adequate vaccination covers the less-endowed countries. Therefore, the global community should take initiatives to speed up the COVID-19 vaccination program in all countries of the world, irrespective of their wealth. Keywords: COVID-19 vaccination; GDP; public health, high-income countries, developing coun-tries

Food Security and Climate Change

Climate change may potentially disrupt progress toward a world without hunger. Today, a clear and consistent global pattern is perceptible of the different impacts of climate change on crop productivity that could have repercussions on food security. Consequently, the stability of the whole food systems may be at risk under climate change because of its unpredictable variations. Indeed, agricultural production is highly vulnerable even to 2°C predictions augmentation for global mean temperatures in 2100, with major implications for poverty and for food security. The climate change impacts seem to be clear in areas currently affected by hunger and undernutrition, which will heighten food insecurity in these parts of the world. Therefore, adapting food systems both to increase food security and to prevent future negative impacts from climate change will require attention to more than just agricultural production. The evidence sustains the need for thoughtful investment in adaptation and mitigation actions toward an efficient management of climate change influences on food security.

Context-specific emergence and growth of the SARS-CoV-2 Delta variant

The Delta variant of concern of SARS-CoV-2 has spread globally causing large outbreaks and resurgences of COVID-19 cases. The emergence of Delta in the UK occurred on the background of a heterogeneous landscape of immunity and relaxation of non-pharmaceutical interventions. Here we analyse 52,992 Delta genomes from England in combination with 93,649 global genomes to reconstruct the emergence of Delta, and quantify its introduction to and regional dissemination across England, in the context of changing travel and social restrictions. Through analysis of human movement, contact tracing, and virus genomic data, we find that the focus of geographic expansion of Delta shifted from India to a more global pattern in early May 2021. In England, Delta lineages were introduced >1,000 times and spread nationally as non-pharmaceutical interventions were relaxed. We find that hotel quarantine for travellers from India reduced onward transmission from importations; however the transmission chains that later dominated the Delta wave in England had been already seeded before restrictions were introduced. In England, increasing inter- regional travel drove Delta's nationwide dissemination, with some cities receiving >2,000 observable lineage introductions from other regions. Subsequently, increased levels of local population mixing, not the number of importations, was associated with faster relative growth of Delta. Among US states, we find that regions that previously experienced large waves also had faster Delta growth rates, and a model including interactions between immunity and human behaviour could accurately predict the rise of Delta there. Delta's invasion dynamics depended on fine scale spatial heterogeneity in immunity and contact patterns and our findings will inform optimal spatial interventions to reduce transmission of current and future VOCs such as Omicron.

Context-specific emergence and growth of the SARS-CoV-2 Delta variant

The Delta variant of concern of SARS-CoV-2 has spread globally causing large outbreaks and resurgences of COVID-19 cases. The emergence of Delta in the UK occurred on the background of a heterogeneous landscape of immunity and relaxation of non-pharmaceutical interventions. Here we analyse 52,992 Delta genomes from England in combination with 93,649 global genomes to reconstruct the emergence of Delta, and quantify its introduction to and regional dissemination across England, in the context of changing travel and social restrictions. Through analysis of human movement, contact tracing, and virus genomic data, we find that the focus of geographic expansion of Delta shifted from India to a more global pattern in early May 2021. In England, Delta lineages were introduced >1,000 times and spread nationally as non-pharmaceutical interventions were relaxed. We find that hotel quarantine for travellers from India reduced onward transmission from importations; however the transmission chains that later dominated the Delta wave in England had been already seeded before restrictions were introduced. In England, increasing inter-regional travel drove Delta's nationwide dissemination, with some cities receiving >2,000 observable lineage introductions from other regions. Subsequently, increased levels of local population mixing, not the number of importations, was associated with faster relative growth of Delta. Among US states, we find that regions that previously experienced large waves also had faster Delta growth rates, and a model including interactions between immunity and human behaviour could accurately predict the rise of Delta there. Delta’s invasion dynamics depended on fine scale spatial heterogeneity in immunity and contact patterns and our findings will inform optimal spatial interventions to reduce transmission of current and future VOCs such as Omicron.

Global pattern of ecosystem respiration tendencies and its implications on terrestrial carbon sink potential

As the largest component of carbon export from terrestrial ecosystems, ecosystem respiration (RECO) determines the carbon stock changes in terrestrial ecosystems. It is essential to accurately simulate the response of RECO to climate change. In this study, by constructing an optimal deep learning model for simulating global-scale RECO, we found that there is a 1–2 years' lagged response of RECO to changes in water conditions and an inconsistency in carbon input (NPP) and output (RECO) trends. The NPP growth trend in global terrestrial ecosystems is greater than that of RECO, with a trend showing increasing carbon sinks, particularly in the northern extra-tropics; while the carbon sink capacity of tropical regions has gradually saturated, showing that the changing trend of RECO is close to that of NPP, which poses a potential risk to the sustainable carbon sink capacity of global ecosystems in the future.

Postcolonialism, Decoloniality, and Epistemologies of the South

Postcolonialism, decoloniality, and epistemologies of the South (ES) are three main ways of critically approaching the consequences of European colonialism in contemporary social, political, and cultural ways of thinking and acting. They converge in highlighting the unmeasurable sacrifice of human life; the expropriation of cultural and natural wealth; and the destruction, by suppressing, silencing, proscribing, or disfiguring, of non-European cultures and ways of knowing. The differences among them stem in part from the temporal and geographical contexts in which they emerged. Postcolonial studies emerged in the 1960s in the aftermath of the political independence of European colonies in Asia and Africa. They focused mainly on the economic, political, and cultural consequences of decolonization, highlighting the postindependence forms of economic dependence, political subordination, and cultural subalternization. They argue that while historical colonialism had ended (territorial occupation and ruling by a foreign country), colonialism continued under different guises. Decolonial studies emerged in the 1990s in Latin America. Since the political independence of the Latin American countries took place in the early 19th century, these analytical currents assumed that colonialism was over, but it had in fact been followed by coloniality, a global pattern of social interaction that inherited all the social and cultural corrosiveness of colonialism. Coloniality is conceived of as an all-encompassing racial understanding of social reality that permeates all realms of economic, social, political, and cultural life. Coloniality is the idea that whatever differs from the Eurocentric worldview is inferior, marginal, irrelevant, or dangerous. The ES, formulated in the 2000s, aim at naming and highlighting ancient and contemporary knowledges held by social groups as they resisted against modern Eurocentric domination. They conceive of modern science as a valid (and precious) type of knowledge but not as the only valid (and precious) type of knowledge; they insist on the possibility of interknowledge and intercultural translation. ES share with postcolonialism the idea that colonialism is not over. However, they insist that modern domination is constituted not only by colonialism but also by capitalism and patriarchy. Like decolonial studies, the ES denounce the cognitive and ontological destruction caused by coloniality, but they focus on the positiveness and creativity that emerge from knowledges born in struggle and on how they translate themselves into alternative ways of knowing and practicing self-determination.

Atmospheric River Representation in the Energy Exascale Earth System Model (E3SM) Version 1.0

The Energy Exascale Earth System Model (E3SM) Project is an ongoing, state-of-the-science Earth system modeling, simulation, and prediction project developed by the U.S. Department of Energy (DOE). With an emphasis on supporting DOE's energy mission, understanding and quantifying how well the model simulates water cycle processes is of particular importance. Here, we evaluate E3SM version v1.0 for its ability to represent atmospheric rivers (ARs), which play significant roles in water vapor transport and precipitation. The characteristics and precipitation associated with global ARs in E3SM at standard resolution (1° × 1°) are compared to the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2). Global pattern of AR frequencies in E3SM show high degrees of correlation (>= 0.97) with MERRA2 and low mean absolute errors (< 1 %) annually, seasonally, and across different ensemble members. However, some large-scale condition biases exist leading to AR biases - most significant of which are: the double-ITCZ, a stronger and/or equatorward shifted subtropical jet during boreal and austral winter, and enhanced northern hemisphere westerlies during summer. By comparing atmosphere-only and fully coupled simulations, we attribute the sources of the biases to the atmospheric component or to a coupling response. Using relationships revealed in Dong et al. (2021), we provide evidence showing the stronger north Pacific jet in winter and enhanced northern hemisphere westerlies during summer associated with E3SM's double-ITCZ and related weaker AMOC, respectively, are the sources of much of the AR biases found in the coupled simulations.

Optic Flow: A History

The concept of optic flow, a global pattern of visual motion that is both caused by and signals self-motion, is canonically ascribed to James Gibson's 1950 book “ The Perception of the Visual World.” There have, however, been several other developments of this concept, chiefly by Gwilym Grindley and Edward Calvert. Based on rarely referenced scientific literature and archival research, this article describes the development of the concept of optic flow by the aforementioned authors and several others. The article furthermore presents the available evidence for interactions between these authors, focusing on whether parts of Gibson's proposal were derived from the work of Grindley or Calvert. While Grindley's work may have made Gibson aware of the geometrical facts of optic flow, Gibson's work is not derivative of Grindley's. It is furthermore shown that Gibson only learned of Calvert's work in 1956, almost a decade after Gibson first published his proposal. In conclusion, the development of the concept of optic flow presents an intriguing example of convergent thought in the progress of science.