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1. Photo response of 164Dy

   O. Papst, V. Werner (September 2020, Physical review)

   Background: Little data is available for the pygmy dipole resonance (PDR) in axially deformed nuclei. Photon scattering experiments are complicated by high level densities in the PDR region and the small energy difference of transitions to the ground state and to excited states. Purpose: We report on an experimental study of the low-energy dipole strength distribution of the well-deformed nucleus 164Dy between 4.0–7.7 MeV. Methods: The low-lying photoresponse of 164Dy has been investigated using the method of nuclear resonance fluorescence using a quasimonochromatic linearly polarized γ -ray beam in the energy range of 4.0–7.7 MeV in steps of 0.2 MeV. Results: For excitation energies between 4 MeV and 5 MeV, sufficiently low level densities allow for the identification of individual states, including level energies, reduced transition widths and branching ratios. Energy-averaged mean decay branching ratios, mean population ratios and partial absorption cross sections were determined above 5 MeV up to the neutron-separation threshold at 7.7 MeV. A Lorentzian-shaped enhancement of the partial photo absorption cross section followed by decays back to the ground-state band is found at 6.10(5) MeV with a width of 0.77(23) MeV. A comparison with results from complementary measurements is performed using the framework of the statistical model. Conclusions: The experimental results for the mean population ratios deviate systematically from the statistical model simulation by 30(6)%. However, they are in agreement within one standard deviation of the simulation. 

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2. Response and adaptation of the transcriptional heat shock response to pressure

   https://doi.org/10.3389/fmicb.2024.1470617  

   Coffin, Carleton H; Fisher, Luke A; Crippen, Sara; Demers, Phoebe; Bartlett, Douglas H; Royer, Catherine A (November 2024, Frontiers in Microbiology)

   IntroductionThe molecular mechanisms underlying pressure adaptation remain largely unexplored, despite their significance for understanding biological adaptation and improving sterilization methods in the food and beverage industry. The heat shock response leads to a global stabilization of the proteome. Prior research suggested that the heat shock regulon may exhibit a transcriptional response to high-pressure stress. MethodsIn this study, we investigated the pressure-dependent heat shock response inE. colistrains using plasmid-borne green fluorescent protein (GFP) promoter fusions and fluorescence fluctuation microscopy. ResultsWe quantitatively confirm that key heat shock genes-rpoH,rpoE,dnaK, andgroEL- are transcriptionally upregulated following pressure shock in both piezosensitiveEscherichia coliand a more piezotolerant laboratory-evolved strain, AN62. Our quantitative imaging results provide the first single cell resolution measurements for both the heat shock and pressure shock transcriptional responses, revealing not only the magnitude of the responses, but also the biological variance involved. Moreover, our results demonstrate distinct responses in the pressure-adapted strain. Specifically,P_groELis upregulated more thanP_dnaKin AN62, while the reverse is true in the parental strain. Furthermore, unlike in the parental strain, the pressure-induced upregulation ofP_rpoEis highly stochastic in strain AN62, consistent with a strong feedback mechanism and suggesting that RpoE could act as a pressure sensor. DiscussionDespite its capacity to grow at pressures up to 62 MPa, the AN62 genome shows minimal mutations, with notable single nucleotide substitutions in genes of the transcriptionally importantbsubunit of RNA polymerase and the Rho terminator. In particular, the mutation in RNAP is one of a cluster of mutations known to confer rifampicin resistance toE. colivia modification of RNAP pausing and termination efficiency. The observed differences in the pressure and heat shock responses between the parental MG1655 strain and the pressure-adapted strain AN62 could arise in part from functional differences in their RNAP molecules. 

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3. Shape of species climate response curves affects community response to climate change

   https://doi.org/10.1111/ele.13688  

   Bonachela, Juan_A; Burrows, Michael_T; Pinsky, Malin_L; Calcagno, ed., Vincent (February 2021, Ecology Letters)

   Abstract Understanding how community composition is reshaped by changing climate is important for interpreting and predicting patterns of community assembly through time or across space. Community composition often does not perfectly correspond to expectations from current environmental conditions, leading to community‐climate mismatches. Here, we combine data analysis and theory development to explore how species climate response curves affect the community response to climate change. We show that strong mismatches between community and climate can appear in the absence of demographic delays or limited species pools. Communities simulated using species response curves showed temporal changes of similar magnitude to those observed in natural communities of fishes and plankton, suggesting no overall delays in community change despite substantial unexplained variation from community assembly and other processes. Our approach can be considered as a null model that will be important to use when interpreting observed community responses to climate change and variability. 

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4. Mechanical Unfolding Response of Proteins

   Popa, Ionel; Berkovich, Ronen (June 2023, ACS)
5. Frequency Response-Based Uncertainty Analysis of Vibration System Utilizing Multiple Response Gaussian Process

   https://doi.org/10.1115/1.4043609  

   Pan, Wangbai; Tang, Guoan; Tang, Jiong (October 2019, Journal of Vibration and Acoustics)

   This research concerns the uncertainty analysis and quantification of the vibration system utilizing the frequency response function (FRF) representation with statistical metamodeling. Different from previous statistical metamodels that are built for individual frequency points, in this research we take advantage of the inherent correlation of FRF values at different frequency points and resort to the multiple response Gaussian process (MRGP) approach. To enable the analysis, vector fitting method is adopted to represent an FRF using a reduced set of parameters with high accuracy. Owing to the efficiency and accuracy of the statistical metamodel with a small set of parameters, Bayesian inference can then be incorporated to realize model updating and uncertainty identification as new measurement/evidence is acquired. The MRGP metamodel developed under this new framework can be used effectively for two-way uncertainty propagation analysis, i.e., FRF prediction and uncertainty identification. Case studies are conducted for illustration and verification. 

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