Human Knee FEA Model for Transtibial Amputee Tibial Cartilage Pressure in Gait and Cycling

Osteoarthritis (OA) is a debilitating disease affecting roughly 31 million Americans. The incidence of OA is significantly higher for persons who have suffered a transtibial amputation. Abnormal cartilage stress can cause higher OA risk, however it is unknown if there is a connection between exercise type and cartilage stress. To help answer this, a tibiofemoral FEA model was created. Utilizing linear elastic isotropic materials and non-linear springs, the model was validated to experimental cadaveric data. In a previous study, 6 control and 6 amputee subjects underwent gait and cycling experiments. The resultant knee loads were analyzed to find the maximum compressive load and the respective shear forces and rotation moments for each trial, which were then applied to the model. Maximum tibial contact stress values were extracted for both the medial and lateral compartments. Only exercise choice in the lateral compartment was found to be a significant interaction (p\u3c0.0001). No other interactions in either compartment were significant. This suggests that cycling reduces the risk for lateral OA regardless of amputation status and medial OA risk is unaffected. This study also developed a process for creating subject-specific FEA models

Deposition of cohesive sediment from turbulent plumes, gravity currents, and turbidity currents

Models for the deposition of cohesive sediment from turbulent plumes (or “buoyant jets”), gravity currents, and turbidity currents are provided in this paper. The cohesive sediment is made up of small particles that aggregate together to form larger flocs, which are in turn broken up by turbulent shear. The equilibrium mean floc size (and thus the equilibrium mean fall speed) is a function of the turbulent dissipation rate and the sediment concentration. The flows are modeled by using integral and box models, with dissipation related to bulk flow properties. For plumes it is shown that there is a well-defined equilibrium fall speed at the virtual origin and that the fall speed changes relatively slowly in the momentum-dominated part of the flow (within one jet length or so of the source). If the flocs are assumed to adjust instantaneously to their equilibrium size, an integral model for a turbulent plume carrying cohesive sediment can be described in terms of two parameters: the angle between the plume and the horizontal at the virtual origin and the (nondimensional) fall speed there. Next, a typical time scale for flocs to adjust to their equilibrium size is identified, and the model is extended to include an equation for the rate of change of the mean floc size along the plume. The time scale over which the mean floc size changes can be compared with a natural time scale for the plume (the time taken for a particle traveling at the mean plume speed to travel a jet length). Thus, in this nonequilibrium model, a further nondimensional parameter is identified, B, which is proportional to the ratio of a typical plume time scale to the typical floc size adjustment time scale. When B is large, the flocs adjust almost instantaneously to the equilibrium size, whereas when B is very small, the flocs remain close to their size at the source. However, whatever the value of B (which is in terms of typical time scales), the local adjustment time scale always tends to zero approaching an idealized source (virtual origin) so that the equilibrium model is always valid there. For plumes injected horizontally, the equilibrium floc size tends to reduce with distance from the source, with any reduction in turbulent shear more than compensated for by the reduction in sediment concentration. The equilibrium model is then applied to two-dimensional and axisymmetric gravity currents and turbidity currents. The gravity currents are assumed to be steady flows driven by a constant source of dense fluid with the sediment having a negligible effect on the fluid density. In contrast, the turbidity currents modeled are initiated by the release of a finite volume of fluid containing the sediment, with the sediment concentration providing the density difference from the ambient fluid. For these flows, the basic scales are identified, and the concentration and deposition distributions given

A Parameter-efficient Multi-subject Model for Predicting fMRI Activity

This is the Algonauts 2023 submission report for team "BlobGPT". Our model consists of a multi-subject linear encoding head attached to a pretrained trunk model. The multi-subject head consists of three components: (1) a shared multi-layer feature projection, (2) shared plus subject-specific low-dimension linear transformations, and (3) a shared PCA fMRI embedding. In this report, we explain these components in more detail and present some experimental results. Our code is available at https://github.com/cmi-dair/algonauts23

OTIVM, MATERIALIDADE E PAISAGEM NAS VILLAE DO ALTO ALENTEJO PORTUGUÊS EM ÉPOCA ROMANA

A arquitectura das villae foi cuidadosamente pensada para permitir o máximo des- frute de uma vivência de gosto urbano e cosmopolita. A atenção dada à inserção da construção na paisagem, as soluções para harmonizar o espaço exterior criando atmosferas favoráveis, a contemplação para o exterior e a criação de espaços e am- bientes construídos que permitissem potenciar o otium e o convivium são discutidos neste trabalho, com exemplos de sítios no Alto Alentejo

Chronic kidney disease, time in therapeutic range and adverse clinical outcomes in anticoagulated patients with non-valvular atrial fibrillation: observations from the SPORTIF trials

Background: Chronic kidney disease (CKD) is highly prevalent in atrial fibrillation (AF) patients and associated with an increased risk of adverse outcomes. Our objectives were to study clinical features associated with CKD in AF patients and the impact of CKD on anticoagulation control, as reflected by time in therapeutic range (TTR). We also determined the impact of CKD and TTR in predicting adverse outcomes. Methods and Results: We analysed pooled datasets from SPORTIF III and V trials, including 3646 patients assigned to warfarin with data on renal function. CKD (creatinine clearance . 70%, whilst diabetes mellitus, aspirin use and CKD were inversely associated with TTR. >. 70%. On Cox regression analysis, CKD was an independent predictor for stroke (p = 0.006) and death (p . 70% was independently associated with a lower risk of stroke (p = 0.024), death (p = 0.001) and major bleeding (p = 0.001). Conclusions: CKD is highly prevalent amongst AF patients and a risk factor for stroke and death. Adjusting for CKD, good quality anticoagulation control (TTR. >. 70%) was an independent predictor for lower risks of stroke, death and major bleeding

Active Shape Modeling of the Hip in the Prediction of Incident Hip Fracture

The objective of this study was to evaluate right proximal femur shape as a risk factor for incident hip fracture using active shape modeling (ASM). A nested case-control study of white women 65 years of age and older enrolled in the Study of Osteoporotic Fractures (SOF) was performed. Subjects (n = 168) were randomly selected from study participants who experienced hip fracture during the follow-up period (mean 8.3 years). Controls (n = 231) had no fracture during follow-up. Subjects with baseline radiographic hip osteoarthritis were excluded. ASM of digitized right hip radiographs generated 10 independent modes of variation in proximal femur shape that together accounted for 95% of the variance in proximal femur shape. The association of ASM modes with incident hip fracture was analyzed by logistic regression. Together, the 10 ASM modes demonstrated good discrimination of incident hip fracture. In models controlling for age and body mass index (BMI), the area under receiver operating characteristic (AUROC) curve for hip shape was 0.813, 95% confidence interval (CI) 0.771–0.854 compared with models containing femoral neck bone mineral density (AUROC = 0.675, 95% CI 0.620–0.730), intertrochanteric bone mineral density (AUROC = 0.645, 95% CI 0.589–0.701), femoral neck length (AUROC = 0.631, 95% CI 0.573–0.690), or femoral neck width (AUROC = 0.633, 95% CI 0.574–0.691). The accuracy of fracture discrimination was improved by combining ASM modes with femoral neck bone mineral density (AUROC = 0.835, 95% CI 0.795–0.875) or with intertrochanteric bone mineral density (AUROC = 0.834, 95% CI 0.794–0.875). Hips with positive standard deviations of ASM mode 4 had the highest risk of incident hip fracture (odds ratio = 2.48, 95% CI 1.68–3.31, p < .001). We conclude that variations in the relative size of the femoral head and neck are important determinants of incident hip fracture. The addition of hip shape to fracture-prediction tools may improve the risk assessment for osteoporotic hip fractures. © 2011 American Society for Bone and Mineral Research

Stratosphere-troposphere transport in a numerical simulation of midlatitude convection

The transport of stratospheric air deep into the troposphere via convection is investigated numerically using the UK Met Office Unified Model. A convective system that formed on 27 June 2004 near southeast England, in the vicinity an upper level potential vorticity anomaly and a lowered tropopause, provides the basis for analysis. Transport is diagnosed using a stratospheric tracer that can either be passed through or withheld from the model’s convective parameterization scheme. Three simulations are performed at increasingly finer resolutions, with horizontal grid lengths of 12, 4, and 1 km. In the 12 and 4 km simulations, tracer is transported deeply into the troposphere by the parameterized convection. In the 1 km simulation, for which the convective parameterization is disengaged, deep transport is still accomplished but with a much smaller magnitude. However, the 1 km simulation resolves stirring along the tropopause that does not exist in the coarser simulations. In all three simulations, the concentration of the deeply transported tracer is small, three orders of magnitude less than that of the shallow transport near the tropopause, most likely because of the efficient dilution of parcels in the lower troposphere