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Epigenetic clocks are DNA methylation-based chronological age prediction models that are commonly employed to study age-related biology. The difference between the predicted and observed age is often interpreted as a form of biological age acceleration, and many studies have measured the impact of environmental and disease-associated factors on epigenetic age. Most epigenetic clocks are fit using approaches that minimize the error between the predicted and observed chronological age, and as a result, they may not accurately model the impact of factors that moderate the relationship between the actual and epigenetic age. Here, we compare epigenetic clocks that are constructed using penalized regression methods to an evolutionary framework of epigenetic aging with the epigenetic pacemaker (EPM), which directly models DNA methylation as a function of a time-dependent epigenetic state. In simulations, we show that the value of the epigenetic state is impacted by factors such as age, sex, and cell-type composition. Next, in a dataset aggregated from previous studies, we show that the epigenetic state is also moderated by sex and the cell type. Finally, we demonstrate that the epigenetic state is also moderated by toxins in a study on polybrominated biphenyl exposure. Thus, we find that the pacemaker provides a robust framework for the study of factors that impact epigenetic age acceleration and that the effect of these factors may be obscured in traditional clocks based on linear regression models.

Summary: Binding events that occur at different times are essential for memory formation. In trace fear conditioning, animals associate a tone and footshock despite no temporal overlap. The hippocampus is thought to mediate this learning by maintaining a memory of the tone until shock occurrence, however, evidence for sustained hippocampal tone representations is lacking. Here, we demonstrate a retrospective role for the hippocampus in trace fear conditioning. Bulk calcium imaging revealed sustained increases in CA1 activity after footshock that were not observed after tone termination. Optogenetic silencing of CA1 immediately after footshock impaired subsequent memory. Additionally, footshock increased the number of sharp-wave ripples compared to baseline during conditioning. Therefore, post-shock hippocampal activity likely supports learning by reactivating and linking latent tone and shock representations. These findings highlight an underappreciated function of post-trial hippocampal activity in enabling retroactive temporal associations during new learning, as opposed to persistent maintenance of stimulus representations.

Background/Objectives: Physical literacy (PL) is essential to the holistic human experience, emphasizing embodied capability and affording opportunities for inclusive engagement. Despite its recent use as a core programming element, PL from the experiential point of view of individuals experiencing disability has yet to be explored. Excluding these perspectives promotes a culture of ableism, one that devalues the embodied capabilities of those experiencing the world differently. The purpose of this study was to highlight the participant perspective related to PL and explore the value individuals experiencing disability attribute to PL and its development. Methods: Using the communities of practice theoretical model of knowledge as a conceptual framework, 13 participants experiencing disability participated in two focus groups. Participants’ experiences were thematized via the use of thematic analysis, and voices were portrayed through composite narratives, highlighting the shared participant experience and value associated with PL. Results: Three themes emerged: (1) imagine the possibilities, (2) dance like nobody's watching, and (3) no wrong way to move. Composite narratives reflect PL as a valued means of exploration and learning, personal growth, and opportunity related to physical activity and social interaction. Participant value was considered to be enhanced via a learning climate affording opportunities for developing autonomy and a sense of belonging. Conclusion: This research provides an authentic understanding of PL within the context of disability, and what might be used to facilitate its development in such an environment. Individuals experiencing disability contributed to this knowledge and must be continually involved to ensure PL development is inclusive to all.

Physical literacy (PL) has been readily accepted and integrated globally, including organizations affording services to individuals experiencing disability. Despite its uptake, recent research has illustrated that understandings of PL reflect the normative standards of those who do not experience disability, leading to practices that diminish the unique and embodied capability of others while simultaneously validating ableism. While a shift towards recognizing and valuing the heterogeneity associated with PL has recently occurred, the ableist narrative persists. As a result, the operationalization of PL directly contradicts its conceptualization, fostering a physical activity climate that continues to marginalize individuals experiencing disability. With this in mind, this paper critically unpacks PL, challenging the existing ableist narrative and offering suggestions to heighten the level of inclusivity that underscores PL. Pathways, where physical activity professionals contribute to reproducing ableism, will be discussed.

With the rapid and widespread uptake of physical literacy (PL), there is potential for instructors to devalue participation of children who experience disability. The aim of the investigation was to understand how instructors who facilitate physical activity for children experiencing disability make sense of PL, and more specifically, how these instructors bring meaning to PL. Using interpretive phenomenological analysis, six instructors engaged in individual, semi-structured interviews. The study rationale was underpinned by the conceptual framework of ecological systems theory, which provided a foundation for the research, guided the structure of the interview guide, and facilitated a reflexive interpretation of the findings. Four themes were generated: Recognizing unique embodiments, The importance of context, Beyond physical competence, and Navigating PL’s dominant discourse. The instructors’ meaning of PL, impacted by relational and environmental influences, reflected the importance of movement skill development, while also embracing diverse embodiment and pedagogical flexibility by giving value to exploratory play, partial participation, family involvement, and willingness to abandon rigid lessons plans.

The replication of submicron surface structures by micro injection molding is a crucial factor in achieving advanced functionalities, such as antimicrobial resistance, in mass-produced plastic products. In this work, we investigate and model the replication quality of laser-induced periodic surface structures by micro injection molding of different bio-based polymers. A comprehensive multiscale model was developed to predict the submicron scale polymer flow, using a numerical model to analyze the polymer behavior in the mold macro cavity and determine the boundary conditions for the filling of the surface structures. The replication of the mold topography was modeled considering topographical parameters, polymer rheology and thermal behavior, and the mold surface energy, which was modified by depositing an atomic layer of alumina on the steel surface structures. The modeling approach was validated against injection molding experiments, in which the mold temperature was varied due to its well-known influence on replication. The sensitivity to polymer selection, mold surface properties, and mold temperature, was captured. A maximum error of 8% showed the accuracy of the multi-scale model.

A major function of the hippocampus is to link discontiguous events in memory. This process can be studied in animals using Pavlovian trace conditioning, a procedure where the conditional stimulus (CS) and unconditional stimulus (US) are separated in time. While the majority of studies have found that trace conditioning requires the dorsal segment of the hippocampus, others have not. This variability could be due to the use of lesion and pharmacological techniques, which lack cell specificity and temporal precision. More recent studies using optogenetic tools find that trace fear acquisition is disrupted by decreases in dorsal CA1 (dCA1) activity while increases lead to learning enhancements. However, comparing these results is difficult given that some studies manipulated the activity of CA1 pyramidal neurons directly and others did so indirectly (e.g., via stimulation of entorhinal cortex inputs). The goal of the current experiments, therefore, was to compare the effects of direct CA1 excitation and inhibition on the encoding and expression of trace fear memories. Our data indicates that stimulation of ArchT in dCA1 pyramidal neurons reduces activity and impairs both the acquisition and retrieval of trace fear. Unlike previous work, direct stimulation of CA1 with ChR2 increases activity and produces deficits in trace fear learning and expression. We hypothesize that this is due to the artificial nature of optogenetic stimulation, which could disrupt processing throughout the hippocampus and in downstream structures.

The Center for Remote Sensing of Ice Sheets (CReSIS) at the University of Kansas has collected approximately 1000 terabytes (TB) of radar depth sounding data over the Arctic and Antarctic ice sheets since 1993 in an effort to map the thickness of the ice sheets and ultimately understand the impacts of climate change and sea level rise. In addition to data collection, the storage, management, and public distribution of the dataset are also primary roles of the CReSIS. The Open Polar Server (OPS) project developed a free and open source infrastructure to store, manage, analyze, and distribute the data collected by CReSIS in an effort to replace its current data storage and distribution approach. The OPS infrastructure includes a spatial database management system (DBMS), map and web server, JavaScript geoportal, and MATLAB application programming interface (API) for the inclusion of data created by the cryosphere community. Open source software including GeoServer, PostgreSQL, PostGIS, OpenLayers, ExtJS, GeoEXT and others are used to build a system that modernizes the CReSIS data distribution for the entire cryosphere community and creates a flexible platform for future development. Usability analysis demonstrates the OPS infrastructure provides an improved end user experience. In addition, interpolating glacier topography is provided as an application example of the system.