Complex materials with internal microstructure such as suspensions and emulsions exhibit time-dependent rheology characterised by viscoelasticity and thixotropy. In many large-scale applications such as turbulent pipe flow, the elastic response occurs on a much shorter time scale than the thixotropy, hence these flows are purely thixotropic. The fundamental dynamics of thixotropic turbulence is poorly understood, particularly the interplay between microstructural state, rheology and turbulence structure. To address this gap, we conduct direct numerical simulations (DNS) of fully developed turbulent pipe flow of a model thixotropic (Moore) fluid as a function of the thixoviscous number $\Lambda$, which characterises the thixotropic kinetic rate relative to turbulence eddy turnover time, ranging from slow ($\Lambda \ll 1$) to fast ($\Lambda \gg 1$) kinetics. Analysis of DNS results in the Lagrangian frame shows that, as expected, in the limits of slow and fast kinetics, these time-dependent flows behave as time-independent purely viscous (generalised Newtonian) analogues. For intermediate kinetics ($\Lambda \sim 1$), the rheology is governed by a path integral of the thixotropic fading memory kernel over the distribution of Lagrangian shear history, the latter of which is modelled via a simple stochastic model for the radially non-stationary pipe flow. The DNS computations based on this effective viscosity closure exhibit excellent agreement with the fully thixotropic model for $\Lambda =1$, indicating that the purely viscous (generalised Newtonian) analogue persists for arbitrary values of $\Lambda \in (0,\infty ^+)$ and across nonlinear rheology models. These results significantly simplify our understanding of turbulent thixotropic flow, and provide insights into the structure of these complex time-dependent flows.

Dispersion in spatio-temporal random flows is dominated by the competition between spatial and temporal velocity resets along particle paths. This competition admits a range of normal and anomalous dispersion behaviours characterised by the Kubo number, which compares the relative strength of spatial and temporal velocity resets. To shed light on these behaviours, we develop a Lagrangian stochastic approach for particle motion in spatio-temporally fluctuating flow fields. For space–time separable flows, particle motion is mapped onto a continuous time random walk (CTRW) for steady flow in warped time, which enables the upscaling and prediction of the large-scale dispersion behaviour. For non-separable flows, we measure Lagrangian velocities in terms of a new sampling variable, the average number of velocity transitions (both temporal and spatial) along pathlines, which renders the velocity series Markovian. Based on this, we derive a Lagrangian stochastic model that represents particle motion as a coupled space–time random walk, that is, a CTRW for which the space and time increments are intrinsically coupled. This approach sheds light on the fundamental mechanisms of particle motion in space–time variable flows, and allows for its systematic quantification. Furthermore, these results indicate that alternative strategies for the analysis of Lagrangian velocity data using new sampling variables may facilitate the identification of (hidden) Markov models, and enable the development of reduced-order models for otherwise complex particle dynamics.

Objectives/Goals: This study aims to explore the relationship between plasma biomarkers (GFAP, NF-L, and IL-1β) and cognitive impairment in moderate to severe TBI patients. We will assess biomarker levels and their link to neurocognitive outcomes at acute and chronic stages of injury. Methods/Study Population: We will recruit 100 patients aged 21 years and older with moderate to severe TBI (Glasgow Coma Score 3–12) from a trauma hospital. Blood samples will be collected at 24–72 hours post-injury and again at 3 and 6 months. Plasma levels of GFAP, NF-L, and IL-1β will be measured using multiplex ELISA. Neurocognitive tests will be administered at 3 and 6 months to assess cognitive function. Correlations will be made between biomarker levels, neurocognitive performance, and disability scores (Disability Rating Scale and Glasgow Outcome Scale). Exosome isolation from plasma will allow for detailed analysis of astrocyte-derived biomarkers and their association with long-term cognitive impairment and recovery. Results/Anticipated Results: We anticipate that plasma levels of GFAP, NF-L, and IL-1β will be elevated in the acute phase of moderate to severe TBI and will correlate with injury severity. At 3 and 6 months, higher levels of IL-1β, in particular, are expected to be strongly associated with cognitive deficits. We also anticipate that biomarkers in astrocyte-derived exosomes will provide more specific insights into long-term neuroinflammation and its impact on cognitive function. These findings could pave the way for targeted, personalized interventions to improve recovery in TBI patients. Discussion/Significance of Impact: This research focuses on inflammation’s role in cognitive impairment and disability in TBI patients. We propose using multiple biomarkers – GFAP, IL-1β, NF-L – paired with advanced techniques like exosomes and multiplex analyses to identify novel therapeutic targets, aiming for personalized treatment strategies, as well as prognosis.

Poet Nikki Giovanni’s death rocked scholarly and literary communities. The occasion of her 9 December 2024 death has prompted reflections on the life and legacy across genres and decades. As others write and talk about Giovanni from a purely “scholarly” angle analyzing her body of work, I offer here a glimpse into Nikki Giovanni the person who loved Black people and who welcomed me into her life and friend circle. I punctuate my essay with references to her poetry but mostly underscore her generosity, compassion, and human kindness infused into her creative expressions. Nikki was a poet’s poet beloved by many. Those who leaned into her wit, her unadulterated truth-telling about US racism, Black love, and Black self-love found in her life and work a refuge from worlds that deny, erase, and devalue. She elevated and amplified Black people and Black women specifically and humanity more broadly.

Virtual reality (VR) for mental health promotion remains understudied in low-income humanitarian settings. We examined the effectiveness of VR in reducing depression with urban refugee youth in Kampala, Uganda. This randomized controlled trial assessed VR alone (Arm 1), VR followed by Group Problem Management Plus (GPM+) (Arm 2) and a control group (Arm 3), with a peer-driven and convenience sample of refugee youth aged 16–25 in Kampala. The primary outcome, depression, was measured with the Patient Health Questionnaire-9. Secondary outcomes included: mental health literacy, mental health stigma, self-compassion, mental well-being and adaptive coping. Analyses were conducted at three time points (baseline, 8 weeks, 16 weeks) using generalized estimating equations. Among participants (n = 335, mean age: 20.77, standard deviation: 3.01; cisgender women: n = 158, cisgender men: n = 173, transgender women: n = 4), we found no depression reductions for Arms 1 or 2 at 16 weeks compared with Arm 3. At 16 weeks, mental health literacy was significantly higher for Arm 2 compared with Arm 3, and self-compassion was significantly higher in Arm 1 and Arm 2 compared with Arm 3. VR alongside GPM+ may benefit self-compassion and MHL among urban refugee youth in Kampala, but these interventions were not effective in reducing depression.

It is shown that McDonald’s generalization of classical Principal Components Analysis to groups of variables maximally channels the total variance of the original variables through the groups of variables acting as groups. A useful equation is obtained for determining the vectors of correlations of the L2 components with the original variables. A calculation example is given.

As an African American deeply impacted by the personal and communal trauma from the police murder of George Floyd in May 2020 and alleged “racial reckoning” that took place globally immediately thereafter, I have personally wrestled with the responses of many non-Black persons to these events. Though the responses came from well-intentioned friends and colleagues trying to be helpful and conciliatory, they resonated as an empty refrain: “I don’t know what it means to be Black, but….” Each time I heard this refrain, I found myself pondering more deeply what and how these folks, and all folks, understand and practice empathy. My experiences and research revealed a similar concern that I witness across many situations in which people think they are being helpful when in fact they are not doing what real empathy requires – being with the person rather than trying to imagine what the person is going through. This article challenges the faulty ways that people have been taught to think about and practice empathy in hopes of offering a model that might facilitate in more meaningful ways ties that bind human hearts and minds.

The hypothesis tested was that macroscopic swelling of montmorillonitic clays is reduced by the presence of interlayer minerals. Fine and coarse clay fractions of Camargo and Panther Greek bentonite samples were artificially interlayered by reaction of Al2(SO4)3 and NaOH in 0∙5% suspensions of the clays. All four clay fractions reacted similarly to artificial interlayering. At an Al:clay ratio of 16 meq Al/g clay the CEC was completely lost, surface area was reduced and X-ray basal spacings were altered. No macroscopic swelling occurred in samples treated with 16 meq of Al/g of clay. At smaller concentrations of hydroxy-aluminum 8 and 2 meq Al/g clay, the clay properties were less drastically altered. Extraction of interlayered clays with Na citrate restored the original C.E.C., surface area, and basal spacings of all samples and resulted in some slight enhancement of C.E.C. and surface areas of the coarse fractions. Treatment with hot Na citrate resulted in an increase in swelling ability but only slight increases in C.E.C. and surface area. Evidence presented supports the hypothesis that macroscopic swelling of montmorillonitic clays is greatly reduced by interlayer materials. Reduced swelling due to interlayering occurs even when other clay properties may be slightly different from those of nontreated samples. Indications are that interlayer material occurs naturally in the clays studied and this may apply to other bentonite deposits.

In his article on tragedy (Diogenes, No. 7), Mr. Charles G. Bell has offered us some provocative insights and opinions. I am compelled to question, however, some of the basic concepts he brings to the interpretation of tragedy.

It would seem that Mr. Bell, despite the depth of his thinking, has embraced several of the current clichés, which perhaps have their origin in the writings of A. C. Bradley. Critics adhering to this school hold that, for one reason or another, it is not possible to write tragedy in the twentieth century and that no work ending in bleak pessimism or despair is tragic. Mr. Bell, combining literary and historical criteria, is particularly severe in his limitation of the field of tragedy and the possibilities open to it. If I read him aright, only Aeschylus, Shakespeare, and the earlier Sophocles (before he fell from grace) have ever really earned admission to the exclusive realm.

Food insecurity, the inadequate or insecure access to food due to financial constraints, is a growing concern in high-income countries like Australia(1). Food insecure adults may have reduced diet quality due to constraints on food purchasing and consumption(2) but further research is needed to understand how the severity of food insecurity impacts diet quality in an Australian setting. This study aimed to examine the relationship between diet quality and increasing severity of household food insecurity using validated measurement tools. A cross-sectional, online survey of Australian adults (aged 18 years+) used the USDA Household Food Security Six-item Short Form to classify respondents as food secure or marginally, moderately, or severely food insecure. The Australian Recommended Food Score (ARFS; score between 0–73) determined diet quality (ARFS total) and sub-scale scores for eight food groups(3), with higher scores indicating higher diet quality. Diet quality score results are further categorised as “needs work” (<33), “getting there” (33-38), “excellent” (39-46) or “outstanding” (47+). Survey-weighted linear regression (adjusted for age, sex, income, education, location, household composition) analyses indicate that 45% of participants were living in households that experienced food insecurity, comprising 7% marginally, 18% moderately and 20% severely food insecure households. The ARFS total survey-weighted mean score for the whole sample (n = 804) was 32.4 (SD = 9.8). As the severity of household food insecurity increased, ARFS scores decreased. Marginally food insecure respondents reported a mean ARFS score three points lower than food-secure adults (B=-2.7; 95%CI [−5.11, −0.34]; p = 0.03), and scores reduced by six points for moderately (B=-5.6; 95%CI [−7.26, −3.90]; p<0.001) and twelve points for severely food insecure respondents (B=-11.5; 95%CI [−13.21, −9.78]; p<0.001). Marginally food insecure respondents had significantly lower vegetable sub-scale scores, moderately food insecure respondents had significantly lower sub-scale scores for all food groups except dairy, severely food insecure respondents had significantly lower scores for all sub-scale scores. Poorer diet quality is evident in adults living with any food insecurity but gets progressively worse as the severity of food insecurity increases. Interventions to reduce food insecurity and increase diet quality are required to prevent adverse nutrition-related health outcomes in food-insecure populations in Australia and beyond.