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  1. Free, publicly-accessible full text available November 1, 2025
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  4. Recent research has highlighted the effectiveness of advanced building controls in reducing the energy consumption of heating, ventilation, and air-conditioning (HVAC) systems. Among advanced building control strategies, deep reinforcement learning control (DRL) shows the potential to achieve energy savings for HVAC systems and has emerged as a promising strategy. However, training DRL requires an interactive environment for the agent, which is challenging to achieve with real buildings due to time and response speed constraints. To address this challenge, a simulation environment serving as a training environment is needed, even though the DRL algorithm does not necessarily need a model. The error between the model and the real building is inevitable in this process, which may influence the efficiency of the DRL controller. To investigate the impact of model error, a virtual testbed was established. A high- fidelity Modelica-based model is developed serving as the virtual building. Three reduced-order models (ROMs) (i.e., 3R2C, Light Gradient Boosting Machine (LightGBM) and artificial neural network (ANN) models) were trained with the historical data generated from the virtual building and were embedded in the training environments of DRL. The sensitivity of ROMs and the Modelica model to random and periodical actions were tested and compared. Deploying the policy trained based on a ROM-based environment, which stands for a surrogate model in reality, into the Modelica-based virtual building testing environment, which stands for real-building, is a practical approach to implementing the DRL control. The performance of the practical DRL controller is compared with rule-based control (RBC) and an ideal DRL controller which was trained and deployed both in the virtual building environment. In the final episode with best rewards of the case study, the 3R2C, LightGBM, and ANN-based DRL outperform the RBC by 7.4%, 14.4%, and 11.4%, respectively in terms of the reward, comprising the weighted sum of energy cost, temperature violations, and the slew rate of the control signal, but falls short of the ideal Modelica-based DRL controller which outperforms RBC by 29.5%. The DRL controllers based on data-driven models are highly unstable with higher maximum rewards but much lower average rewards which might be caused by the significant prediction defect in certain action regions of the data-driven model. 
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  5. Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond the Standard Model of particle physics. One of the isotopes under investigation isXe136, which would double beta decay intoBa136. Detecting the singleBa136daughter provides a sort of ultimate tool in the discrimination against backgrounds. Previous work demonstrated the ability to perform single atom imaging of Ba atoms in a single-vacancy site of a solid xenon matrix. In this paper, the effort to identify signal from individual barium atoms is extended to Ba atoms in a hexa-vacancy site in the matrix and is achieved despite increased photobleaching in this site. Abrupt fluorescence turn-off of a single Ba atom is also observed. Significant recovery of fluorescence signal lost through photobleaching is demonstrated upon annealing of Ba deposits in the Xe ice. Following annealing, it is observed that Ba atoms in the hexa-vacancy site exhibit antibleaching while Ba atoms in the tetra-vacancy site exhibit bleaching. This may be evidence for a matrix site transfer upon laser excitation. Our findings offer a path of continued research toward tagging of Ba daughters in all significant sites in solid xenon.

    Published by the American Physical Society2024 
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    Free, publicly-accessible full text available November 1, 2025
  6. Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-βdecay detector (5metric ton, 90%Xe136, 10%Xe134) to evaluate its sensitivity to supernova neutrinos. Predictions for event rates and detectable signatures were modeled using the Model of Argon Reaction Low Energy Yields (MARLEY) event generator. We find good agreement between MARLEY’s predictions and existing theoretical calculations of the inclusive cross sections at supernova neutrino energies. The interactions modeled by MARLEY were simulated within the nEXO simulation framework and were run through an example reconstruction algorithm to determine the detector’s efficiency for reconstructing these events. The simulated data, incorporating the detector response, were used to study the ability of nEXO to reconstruct the incident electron-neutrino spectrum and these results were extended to a larger xenon detector of the same isotope enrichment. We estimate that nEXO will be able to observe electron-neutrino interactions with xenon from supernovae as far as 5–8 kpc from Earth, while the ability to reconstruct incident electron-neutrino spectrum parameters from observed interactions in nEXO is limited to closer supernovae.

    Published by the American Physical Society2024 
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    Free, publicly-accessible full text available November 1, 2025
  7. null (Ed.)
    Histone post-translational modifications (PTMs) are epigenetic marks that modify the state of chromatin and lead to alterations in gene expression. Advances in mass spectrometry have enabled the high-throughput analysis of histone PTMs without the need for prior knowledge of individual PTMs of interest. In this study, the global histone PTM landscape was analyzed in the gills, kidney, and testes of Mozambique tilapia (Oreochromis mossambicus) through tandem mass spectrometry using data dependent acquisition (DDA-LCMS2) and PTM mapping approaches. PTM assignment to a specific amino acid was validated using A-score and localization probability scores that are based on the detection of diagnostic MSMS ions. These values signify the robustness of PTM assignment to a specific residue within the protein sequence. For PTMs that were represented by both modified and unmodified versions of the corresponding peptide, the stoichiometry was calculated and compared between tissues. We have identified multiple types of histone PTMs and assigned them to specific residues in each tissue. These PTMs include acetylation, methylation, demethylation, trimethylation, phosphorylation/ dehydration, and ubiquitination. Our results indicate that the gills, kidney, and testes each display a unique profile of histone PTMs. These data provide a strong basis for the generation of spectral libraries that enable high-throughput quantitative analyses of histone PTM stoichiometry on a global scale in tilapia exposed to diverse environmental and developmental contexts. 
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  8. null (Ed.)