A virtual world of paleontology

Computer-aided visualization and analysis of fossils has revolutionized the study of extinct organisms. Novel techniques allow fossils to be characterized in three dimensions and in unprecedented detail. This has enabled paleontologists to gain important insights into their anatomy, development, and preservation. New protocols allow more objective reconstructions of fossil organisms, including soft tissues, from incomplete remains. The resulting digital reconstructions can be used in functional analyses, rigorously testing long-standing hypotheses regarding the paleobiology of extinct organisms. These approaches are transforming our understanding of long-studied fossil groups, and of the narratives of organismal and ecological evolution that have been built upon them

Functional morphology of the Triassic apex predator <i>Saurosuchus galilei</i> (Pseudosuchia: Loricata) and convergence with a post‐Triassic theropod dinosaur

Pseudosuchian archosaurs, reptiles more closely related to crocodylians than to birds, exhibited high morphological diversity during the Triassic and are thus associated with hypotheses of high ecological diversity during this time. One example involves basal loricatans which are non‐crocodylomorph pseudosuchians traditionally known as “rauisuchians.” Their large size (5–8+ m long) and morphological similarities to post‐Triassic theropod dinosaurs, including dorsoventrally deep skulls and serrated dentitions, suggest basal loricatans were apex predators. However, this hypothesis does not consider functional behaviors that can influence more refined roles of predators in their environment, for example, degree of carcass utilization. Here, we apply finite element analysis to a juvenile but three‐dimensionally well‐preserved cranium of the basal loricatan Saurosuchus galilei to investigate its functional morphology and to compare with stress distributions from the theropod Allosaurus fragilis to assess degrees of functional convergence between Triassic and post‐Triassic carnivores. We find similar stress distributions and magnitudes between the two study taxa under the same functional simulations, indicating that Saurosuchus had a somewhat strong skull and thus exhibited some degree of functional convergence with theropods. However, Saurosuchus also had a weak bite for an animal of its size (1015–1885 N) that is broadly equivalent to the bite force of modern gharials (Gavialis gangeticus). We infer that Saurosuchus potentially avoided tooth–bone interactions and consumed the softer parts of carcasses, unlike theropods and other basal loricatans. This deduced feeding mode for Saurosuchus increases the known functional diversity of basal loricatans and highlights functional differences between Triassic and post‐Triassic apex predators

Intermittency in the Joint Cascade of Energy and Helicity

The statistics of the energy and helicity fluxes in isotropic turbulence are studied using high resolution direct numerical simulation. The scaling exponents of the energy flux agree with those of the transverse velocity structure functions through refined similarity hypothesis, consistent with Kraichnan's prediction \cite{Kr74}. The helicity flux is even more intermittent than the energy flux and its scaling exponents are closer to those of the passive scalar. Using Waleffe's helical decomposition, we demonstrate that the existence of positive mean helicity flux inhibits the energy transfer in the negative helical modes, a non-passive effect

The interplay between helicity and rotation in turbulence: implications for scaling laws and small-scale dynamics

Invariance properties of physical systems govern their behavior: energy conservation in turbulence drives a wide distribution of energy among modes, observed in geophysical or astrophysical flows. In ideal hydrodynamics, the role of helicity conservation (correlation between velocity and its curl, measuring departures from mirror symmetry) remains unclear since it does not alter the energy spectrum. However, with solid body rotation, significant differences emerge between helical and non-helical flows. We first outline several results, like the energy and helicity spectral distribution and the breaking of strict universality for the individual spectra. Using massive numerical simulations, we then show that small-scale structures and their intermittency properties differ according to whether helicity is present or not, in particular with respect to the emergence of Beltrami-core vortices (BCV) that are laminar helical vertical updrafts. These results point to the discovery of a small parameter besides the Rossby number; this could relate the problem of rotating helical turbulence to that of critical phenomena, through renormalization group and weak turbulence theory. This parameter can be associated with the adimensionalized ratio of the energy to helicity flux to small scales, the three-dimensional energy cascade being weak and self-similar

Effect of filter type on the statistics of energy transfer between resolved and subfilter scales from a-priori analysis of direct numerical simulations of isotropic turbulence

The effects of different filtering strategies on the statistical properties of the resolved-to-sub-filter scale (SFS) energy transfer are analyzed in forced homogeneous and isotropic turbulence. We carry out a priori analyses of statistical characteristics of SFS energy transfer by filtering data obtained from direct numerical simulations (DNS) with up to $2048^3$ grid points as a function of the filter cutoff scale. In order to quantify the dependence of extreme events and anomalous scaling on the filter, we compare a sharp Fourier Galerkin projector, a Gaussian filter and a novel class of Galerkin projectors with non-sharp spectral filter profiles. Of interest is the importance of Galilean invariance and we confirm that local SFS energy transfer displays intermittency scaling in both skewness and flatness as a function of the cutoff scale. Furthermore, we quantify the robustness of scaling as a function of the filtering type

Cytomegalovirus infection of human kidney cells in vitro

Cytomegalovirus infection of human kidney cells in vitro. To study which structures of a kidney allograft are the main targets for cytomegalovirus (CMV), human glomerular epithelial and mesangial cells, as well as tubular epithelial and endothelial cells were isolated by steel meshes of different pore sizes and enzymatic treatments. The various cultured cell types were characterized by morphology and specific antibodies. Human CMV was inoculated onto cell monolayers using two different culture methods: conventional tissue culture and rapid shell vial culture. To analyze whether CMV had a direct effect on the immunologic properties of kidney parenchymal cells, MHC class I and class II antigen expression was estimated before and after the infection. CMV infected all kidney cells identically. All cells expressed class I strongly after the infection, but they were class I positive prior to infection. Class II antigens were not expressed on the cell surface either before or after the infection. In conclusion, human kidney cells of glomerular, tubular and vascular origin were all infected by CMV without any difference. CMV had no significant direct effects on the antigenic properties of the cells

Evaluation of the impact of a school gardening intervention on children's fruit and vegetable intake: a randomised controlled trial.

Background: Current academic literature suggests that school gardening programmes can provide an interactive environment with the potential to change children’s fruit and vegetable intake. This is the first cluster randomised controlled trial (RCT) designed to evaluate whether a school gardening programme can have an effect on children’s fruit and vegetable intake. Methods: The trial included children from 23 schools; these schools were randomised into two groups, one to receive the Royal Horticultural Society (RHS)-led intervention and the other to receive the less involved Teacher-led intervention. A 24-hour food diary (CADET) was used to collect baseline and follow-up dietary intake 18 months apart. Questionnaires were also administered to evaluate the intervention implementation. Results: A total of 641 children completed the trial with a mean age of 8.1 years (95% CI: 8.0, 8.4). The unadjusted results from multilevel regression analysis revealed that for combined daily fruit and vegetable intake the Teacher-led group had a higher daily mean change of 8 g (95% CI: −19, 36) compared to the RHS-led group -32 g (95% CI: −60, −3). However, after adjusting for possible confounders this difference was not significant (intervention effect: −40 g, 95% CI: −88, 1; p = 0.06). The adjusted analysis of process measures identified that if schools improved their gardening score by 3 levels (a measure of school gardening involvement - the scale has 6 levels from 0 ‘no garden’ to 5 ‘community involvement’), irrespective of group allocation, children had, on average, a daily increase of 81 g of fruit and vegetable intake (95% CI: 0, 163; p = 0.05) compared to schools that had no change in gardening score. Conclusions: This study is the first cluster randomised controlled trial designed to evaluate a school gardening intervention. The results have found very little evidence to support the claims that school gardening alone can improve children’s daily fruit and vegetable intake. However, when a gardening intervention is implemented at a high level within the school it may improve children’s daily fruit and vegetable intake by a portion. Improving children’s fruit and vegetable intake remains a challenging task

The potential of physical activity and technology interventions to reduce anxiety in older adults

Background: Older adults have low levels of mental health literacy relating to anxiety, which may explain why they delay or do not seek help. Emerging evidence supports effectiveness of lifestyle interventions, including physical activity (PA), in reducing anxiety. The COVID-19 pandemic has highlighted technology's potential to facilitate healthcare provision. We explored older adults’ understanding of anxiety, perspectives on whether PA interventions could reduce anxiety, and whether technology could facilitate this. Methods: The INDIGO trial evaluated a PA intervention for participants aged 60 years and above, at risk of cognitive decline, and not meeting PA guidelines at baseline. Twenty-nine trial completers attended follow-up semi-structured qualitative interviews. Results: Thematic analysis revealed participants’ diverse understanding of anxiety with some relating anxiety to worry, uncertainty and fear, as well as physical manifestations and feeling out of control, while others found the concept confusing. Participants generally thought that PA interventions could reduce anxiety through “mindful” and/or “physiological” processes. Views about technology were more polarised, possibly reflecting a “digital divide”. Participants expressed that technology could help with information provision, health monitoring and motivation. Participants were open to using wearable activity monitors, online platforms and portable devices. Limitations: Participants had completed a PA intervention trial, had relatively high education levels and interviews were only conducted in English. Conclusions: Results highlight the importance of providing more information and education about anxiety to older adults to increase understanding and help-seeking. Findings also support likely acceptability of PA interventions for anxiety, with the option of technology as a facilitator

Anxiety, depression, and comorbid anxiety and depression: Risk factors and outcome over two years

Background: This study aimed to determine: (1) the prevalence of depression, anxiety, and depression associated with anxiety (DA); (2) the risk factor profile of depression, anxiety, and DA; (3) the course of depression, anxiety, and DA over 24 months. Methods: Two-year longitudinal study of 20,036 adults aged 60+ years. We used the Patient Health Questionnaire and the Hospital Anxiety and Depression Scale anxiety subscale to establish the presence of depression and anxiety, and standard procedures to collect demographic, lifestyle, psychosocial, and clinical data. Results: The prevalence of anxiety, depression, and DA was 4.7%, 1.4%, and 1.8%. About 57% of depression cases showed evidence of comorbid anxiety, while only 28% of those with clinically significant anxiety had concurrent depression. There was not only an overlap in the distribution of risk factors in these diagnostic groups but also differences. We found that 31%, 23%, and 35% of older adults with anxiety, depression, and DA showed persistence of symptoms after two years. Repeated anxiety was more common in women and repeated depression in men. Socioeconomic stressors were common in repeated DA. Conclusions: Clinically significant anxiety and depression are distinct conditions that frequently coexist in later life; when they appear together, older adults endure a more chronic course of illness