Evolution: functional evolution of nuclear structure.

The evolution of the nucleus, the defining feature of eukaryotic cells, was long shrouded in speculation and mystery. There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs. Recent studies have identified many components of the nuclear envelope in living Opisthokonts, the eukaryotic supergroup that includes fungi and metazoan animals. These components include diverse chromatin-binding membrane proteins, and membrane proteins with adhesive lumenal domains that may have contributed to the evolution of nuclear membrane architecture. Further discoveries about the nucleoskeleton suggest that the evolution of nuclear structure was tightly coupled to genome partitioning during mitosis

A share in the sands: trips, pits and potholes in Accra, Ghana

This article deploys sand as a potential way of engaging with contemporary livelihoods in the Ghanaian city of Accra - one of many metropolitan nodes in an urbanizing region of West Africa. Both as a very real material at the heart of concrete urbanization and as metaphorically indicative of the shifting landscapes of opportunity and income on which lives and livelihoods are marked out, sand is offered as a way of seeing and writing about the city. The article brings these two facets of urban sand together in more concrete ways, considering how the material production of the city becomes the uneven, uncertain ground of urban life-making. Drawing from fourteen months of ethnographic fieldwork in Accra, the article engages with the movements of sand across the city, as it travels from extraction zones (or pits) to lorries and then to places of consumption. By honing in on the material behaviours and temporal junctures of sand as it shifts its shape, form and directions, the article draws out the ways in which sand emerges as a platform for exchange, negotiation and ultimately income for different people across the city region. In turn, it offers a share in the sands as a tentative holding space for the kinds of claims made on and through sand, positioning them as indicative of a dweller-led, emergent politics that claims a share of an income, livelihood and urban future

Bridging the Digital Divide: Using Ecological Modeling to Enhance Adult Student Recruitment and Retention in Higher Education

Higher education is at a crossroads. An enrollment cliff (Kline, 2019) looms and global instability only exacerbates the need for higher and continuing education. The global COVID-19 pandemic of 2020 highlighted the problem, and despite the evolutions in technology and Internet connectivity, there is still a chasm regarding equity of digital access. This applied dissertation study examined the barriers that exist for returning adult students to higher education and the digital divide in Louisiana. The study focused on the potential adult student population of Louisiana who have some college experience but no bachelor’s degree. Designed using archival research methods, the study uses maps for ecological modeling. The extent to which the digital divide impacts the potential adult student population of the state of Louisiana was explored through ecological models in the form of maps created using openly sourced government data (the ACS and the FCC Form 477). The theoretical considerations of population ecology and a theory about the digital divide, van Dijk’s resources and appropriation theory were explored. As well as two conceptual frameworks, the Spatially Aware Technology Utilization Model (SATUM) and the Three Domains of Sustainability used to frame the interpretation that conclude that access, ability, and affordability are the three domains required for stability and use of the Internet. The results from the study found that both geographic location and socio-economic characteristics do seem to impact access to the Internet. The analysis includes recommendations for addressing barriers to adult student recruitment and retention through the three components needed to create organizational stability: environmental factors, social factors, and economic factors

Urban futures: idealization, capitalization, securitization

This article offers an analytical reflection on how urban futures have been imagined throughout history and into the present. Considering this question at a global scale, it examines the place of urbanization within the development of the modern/colonial order, accounting for the imagined futures that have supported this world-historical process. Three thematic sections—idealization, capitalization, and securitization—frame the discussion. Capturing desires for societal betterment alongside attempts to extract economic value and imperatives to govern anticipated threats, these heuristics provide insight into forms of urban future-making and future-thinking that continue to reverberate across contemporary projects, debates, and struggles. This lays the groundwork for the critical analysis of urban futures that identifies what is at stake in imagining the future of cities in one way rather than another

Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria.

Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen-protium and deuterium-that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ(2)H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ(2)H suggest much potential as an environmental recorder of metabolism

Covid-19 riskscapes: viral risk perceptions in the African Great Lakes

In this article we explore Covid-19 riskscapes across the African Great Lakes region. Drawing on fieldwork across Uganda and Malawi, our analysis centers around how two mobile, trans-border figures – truck drivers and migrant traders – came to be understood as shifting, yet central loci of perceived viral risk. We argue that political decision-making processes, with specific reference to the influence of Covid-19 testing regimes and reported disease metrics, aggravated antecedent geographies of blame targeted at mobile “others”. We find that using grounded riskscapes to examine localised renditions of risk reveals otherwise neglected forms of discriminatory discourse and practice

Why So Much Ado About a Hairdo? Examining How the Hair Choices of Black Women Vary by Occupation

To better understand negative stereotypes and biases against natural Black hairstyles (e.g., afros, braids, dreadlocks), this study examines the hair style choices of Black women working in four occupational groups (finance, medicine, law, and technology). Using literature on identity shifting, professional identity, and professional appearance norms, we predicted variation in the hairstyle choices of Black women employed in these four occupations. Results indicate Black women technology professionals were significantly more likely to wear natural hairstyles than any of the other three occupations. Black women lawyers were significantly less likely than either physicians or women in technology to wear natural hairstyles. As predicted, the more conservative and formal the work environment, the more likely Black woman adjust their hairstyle to mirror white standards of what is viewed as professional

Shifting sands in Accra, Ghana: the ante-lives of urban form

This thesis thinks with sand and its fundamental relationship to the making of the city. Sand is a material of our shared contemporary. Constituting roads, buildings, fracking technologies, computer chips, glass and land itself, this grainy material is at ‘the core of our daily lives’ (Beiser, 2018:2). This ubiquity has generated global demand, with sand and gravel constituting the largest volume of solid material extracted worldwide (UNEP, 2014). Yet, despite the centrality of sand to our social reproduction, as well as evidence of its eco-political implications (Beiser, 2018), limited academic work has engaged with this material. Drawing on fourteen months of ethnographic fieldwork in the expanding West African city of Accra, this thesis unpacks more specifically the processes through which sand is drawn into the urban process, or indeed urbanised. While sand – mixed with cement and water – is destined to become part of the city’s expanding urban form, this thesis looks instead to the processes that take shape prior to sand’s manifestation as the material building blocks of the city. In this way, this thesis details the before lives – or ante-lives – of urban form. The thesis details the practices of extraction from mines at the sprawling edges of Accra, engages with the labours that surround sand’s extraction and movement and deploys innovative ways of scripting the anxious worlds of the city’s shifting landscapes. In this way, the thesis shows that urbanisation must be understood as a set of unfolding interfaces between geologic forces, ecological processes, historical conditions, cultural forms and political-economic regimes. Together, the chapters in this thesis present a significant contribution at the articulation of urban political ecology (UPE), geosocial analyses, extractivism, [African] urbanism, postcolonialism, labour practices and ethnography, meanwhile offering up novel ways of reading the shifting landscapes of Accra’s ‘urban now’ (Baloji and De Boeck, 2017)

Experiences with the Streptococcus mutans in Lakota Sioux (SMILeS) Study: Risk Factors for Caries in American Indian Children 0-3 Years

Severe Early Childhood Caries (S-ECC) is a terribly aggressive and devastating disease that is all too common in lower socio-economic children, but none more so that what is encountered in American Indian Tribes. Nationwide, approximately 27% of 2-5 year olds have decay while 62% percent of American Indian/Alaska Native children in the same age group have a history of decay (IHS 2010, NHANES 1999-2002). We have conducted a study of children from birth to 36 months of age on Pine Reservation to gain a better understanding of the variables that come into play in the development of this disease, from transmission and acquisition of Streptococcus mutans genotypes from mother to child to multiple dietary and behavioral components. This article describes how we established a direct partnership with the Tribe and the many opportunities and challenges we faced in performing this 5-year field study