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Abstract MotivationThere is a growing interest in longitudinal omics data paired with some longitudinal clinical outcome. Given a large set of continuous omics variables and some continuous clinical outcome, each measured for a few subjects at only a few time points, we seek to identify those variables that co-vary over time with the outcome. To motivate this problem we study a dataset with hundreds of urinary metabolites along with Tuberculosis mycobacterial load as our clinical outcome, with the objective of identifying potential biomarkers for disease progression. For such data clinicians usually apply simple linear mixed effects models which often lack power given the low number of replicates and time points. We propose a penalized regression approach on the first differences of the data that extends the lasso + Laplacian method [Li and Li (Network-constrained regularization and variable selection for analysis of genomic data. Bioinformatics 2008;24:1175–82.)] to a longitudinal group lasso + Laplacian approach. Our method, PROLONG, leverages the first differences of the data to increase power by pairing the consecutive time points. The Laplacian penalty incorporates the dependence structure of the variables, and the group lasso penalty induces sparsity while grouping together all contemporaneous and lag terms for each omic variable in the model. ResultsWith an automated selection of model hyper-parameters, PROLONG correctly selects target metabolites with high specificity and sensitivity across a wide range of scenarios. PROLONG selects a set of metabolites from the real data that includes interesting targets identified during EDA. Availability and implementationAn R package implementing described methods called “prolong” is available at https://github.com/stevebroll/prolong. Code snapshot available at 10.5281/zenodo.14804245. 

We present extensive proper motion measurements of the Crab Nebula made from Canada-France-Hawaii Telescope MegaPrime/MegaCam images taken in 2007, 2016, and 2019. A total of 19974 proper motion vectors with uncertainty < 10 mas yr−1 located over the majority of the Crab Nebula are used to map the supernova remnant’s two-dimensional expansion properties that reflect the dynamics of the original explosion, acceleration of ejecta imparted by spin-down energy from the pulsar, and interaction between the ejecta and surrounding circumstellar material (CSM). The average convergence date we derive is 1105.5 ± 0.5 CE, which is 15-35 years earlier compared to most previous estimates. We find that it varies as a function of position angle around the nebula, with the earliest date and smallest proper motions measured along the equator defined by the east and west bays. The lower acceleration of material along the equatorial plane may be indicative of the supernova’s interaction with a disk-like CSM geometry. Comparing our measurements to previous analytical solutions of the Crab’s expansion and our own numerical simulation using the moving mesh hydrodynamics code Sprout, we conclude that the ejecta have relaxed closer to homologous expansion than expected for the commonly adopted pulsar spindown age of τ ∼ 700 yr and a pulsar wind nebula (PWN) still evolving inside the flat part of the ejecta density profile. These findings provide further evidence that the PWN has broken out of the inner flat part of the supernova ejecta density profile and has experienced “blowout”. 

Materials that undergo singlet fission are of interest for their use in light-harvesting, photocatalysis, and quantum information science, but their ability to undergo fission can be sensitive to local variations in molecular packing. Herein we employ transient absorption microscopy, molecular dynamics simulations, and electronic structure calculations to interrogate how structures found at the edges of orthorhombic rubrene crystals impact singlet fission. Within a micrometer-scale spatial region at the edges of rubrene crystals, we find that the rate of singlet fission increases nearly 4-fold. This observation is consistent with formation of a region at crystal edges with reduced order that accelerates singlet fission by disrupting the symmetry found in rubrene’s orthorhombic crystal structure. Our work demonstrates that structural distortions of singlet fission materials can be used to control fission in time and in space, potentially offering a means of controlling this process in light harvesting and quantum information applications. 

Arctica islandica (ocean quahog), a commercially-important, long-lived bivalve species, is abundant on much of the northeastern United States continental shelf. Several recent studies have noted increases in growth rates of these clams over the last 200 years at some locations in the southern Mid-Atlantic Bight region whereas growth rates at sites farther north have remained constant through time. It has been suggested that these changes in growth rate are related to warming in the more southerly sites. However, a direct comparison between site-specific bottom-water temperatures and A. islandica growth rates has not been done. We present oxygen isotope data measured in Arctica islandica shells, a proxy for seawater temperature, paired with simulated temperature from high-resolution ocean model output to investigate the relationship between A. islandica shell growth rate and bottom water temperatures throughout the northeastern United States continental shelf. The relationship between oxygen isotopes and growth rate in A. islandica is assessed at several locations, including the continental shelf offshore New Jersey and Long Island, and the Georges Bank region. Bottom water temperature trends at these locations are further assessed using the VIKING20X ocean model, which uses JRA55-do (55-year Japanese Atmospheric Reanalysis for driving ocean-sea-ice models) atmospheric forcing from 1958 to present and nests a 1/20° Atlantic Ocean in a 1 ⁄ 4° global domain. The results of this work have implications for the ocean quahog fishery, in particular as water temperatures off the eastern coast of the United States are predicted to continue to increase in response to global climate change. Additionally, this research lends insights into the use of A. islandica growth as a paleoclimate proxy for bottom water temperature. 

We present two-dimensional white-light spectroscopy (2DWL) measurements of binary and ternary bulk heterojunctions of the polymer donor PM6 mixed with state-of-the-art nonfullerene acceptors Y6 or IT4F. The ternary film has a shorter lifetime and faster spectral diffusion than either of the binary films. 2D line shape analysis of the PM6 ground state bleach with a Kubo model determines that all three films have similar amplitudes of fluctuations (Δ = 0.29 fs–1) in their transition frequencies, but different relaxation times (ranging from 102 to 24 fs). The ternary film exhibits faster dynamics than either of the binary films. The short lifetime of the ternary blend is consistent with increased photoexcitation transfer and the fast frequency fluctuations are consistent with structural dynamics of aliphatic side chains. These results suggest that the femtosecond fluctuations of PM6 are impacted by the choice of the acceptor molecules. We hypothesize that those dynamics are either indicative, or perhaps the initial source, of structural dynamics that ultimately contribute to solar cell operation. 

The STEM Center at Sam Houston State University (SHSU) has received funding from the National Science Foundation (NSF - IUSE) and was established in 2017. The STEM Center seeks to increase the number and quality of STEM graduates by establishing a strong foundation for learning using innovative teaching practices, supporting students in finding research and internship opportunities, and building lifelong skills needed for advancement and leadership in STEM careers. The center is in one of the STEM buildings with two fully equipped classrooms and office space for full-time staff members. The center staff collaborates with university-wide programs to promote STEM education and contribute to the university’s quality enhancement plan (QEP). The paper shares details regarding faculty and student involvement, the development of preparatory courses, institution-wide resources, and student outcomes from the project with the academic community.