6,249 research outputs found

    Use of steel and tantalum apparatus for molten Cd-Mg-Zn alloys

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    Steel and tantalum apparatus contains various ternary alloys of cadmium, zinc, and magnesium used in pyrochemical processes for the recovery of uranium-base reactor fuels. These materials exhibit good corrosion resistance at the high temperatures necessary for fuel separation in liquid metal-molten salt solvents

    Influence of Pocket Gopher Mounds on Nonnative Plant Establishment in a Shrubsteppe Ecosystem

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    Soil disturbances across a wide range of spatial scales have been found to promote the establishment of invasive plant species. This study addresses whether mounds built by northern pocket gophers (Thomomys talpoides) in the shrubsteppe environment of north central Washington are facilitating plant invasions into native-dominated fields. Research was conducted in native-dominated plant communities adjacent to ex-arable, nonnative-dominated fields. To determine the effect of mounds on plant growth, we recorded new establishment and persistence of all plant species over 2 growing seasons on 10–19 mound and intermound areas in 10 fields. Nonnative plant establishment was not affected by mounds, but native plant establishment, particularly of the dominant native Pseudoroegneria spicata was lower on mounds than on intermounds. Early in the growing season, mounds had reduced soil moisture, bulk density, soil strength, N mineralization rates, and total N and C concentrations, and similar extractable NO3 – concentrations relative to intermound soils. Our results did not suggest that soil disturbance improved nonnative growth resulting in competitive suppression of natives; rather, our results suggested that low soil moisture and slow N mineralization rates on mounds in this ecosystem present relatively stressful conditions for native plant growth

    Investigation into the role of pump to signal power ratio in FWM-based phase preserving amplitude regeneration

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    We carry out a detailed experimental characterization of a four-wave mixing based amplitude limiter in highly nonlinear fiber based on the Bessel-like power transfer characteristics and highlight trade-offs for phase preserving capabilities

    Overweight and obesity in a Swiss city: 10-year trends

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    Abstract Background Increased rates of overweight/obesity have been reported in recent years in developed countries. This population study of healthy subjects evaluated the changes in overweight/obesity prevalence in 2003, compared with 1993, and determined the association of age, sex and leisure-time activity with body mass index (BMI), fat-free mass index (FFMI) and fat mass index (FMI). Design Two transversal samples of convenience. Participants Healthy volunteers (1993, n=802; 2003, n=1631). Methods Fat-free mass was determined using the bioelectrical impedance multiple regression equation. Multivariable linear regression, including confounding variables (age, sex, leisure-time activity), was used to model the body composition evolution between the 1993 and the 2003 subjects. Results BMI and FMI were higher in 2003 than in 1993, P<0.001. FFMI was not higher in 2003 than in 1993, P=0.38. More subjects were overweight/obese in 2003 than in 1993 (27.5 versus 17.2%, chi-square P<0.001), and had a high FFMI (30.2 versus 21.8%, chi-square P<0.001) and high FMI (28.0 versus 20.3%, chi-square P<0.001). Multivariate linear regressions showed that leisure-time activity was negatively, and sex, age and inclusion year were positively associated with BMI, FFMI and FMI (the exception was a negative association with sex) (P<0.001). Conclusion Overweight prevalence increased between 1993 and 2003 in a Swiss city, and was associated with a higher fat mass. This observation remained statistically significant after adjustment for age, sex and leisure-time activit

    Quantum Calculation of Inelastic CO Collisions with H. II. Pure Rotational Quenching of High Rotational Levels

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    Carbon monoxide is a simple molecule present in many astrophysical environments, and collisional excitation rate coefficients due to the dominant collision partners are necessary to accurately predict spectral line intensities and extract astrophysical parameters. We report new quantum scattering calculations for rotational deexcitation transitions of CO induced by H using the three-dimensional potential energy surface~(PES) of Song et al. (2015). State-to-state cross sections for collision energies from 10−5^{-5} to 15,000~cm−1^{-1} and rate coefficients for temperatures ranging from 1 to 3000~K are obtained for CO(v=0v=0, jj) deexcitation from j=1−45j=1-45 to all lower j′j' levels, where jj is the rotational quantum number. Close-coupling and coupled-states calculations were performed in full-dimension for jj=1-5, 10, 15, 20, 25, 30, 35, 40, and 45 while scaling approaches were used to estimate rate coefficients for all other intermediate rotational states. The current rate coefficients are compared with previous scattering results using earlier PESs. Astrophysical applications of the current results are briefly discussed.Comment: 8 figures, 1 tabl

    TIAMMAt: leveraging biodiversity to revise protein domain models, evidence from innate immunity

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tassia, M. G., David, K. T., Townsend, J. P., & Halanych, K. M. TIAMMAt: leveraging biodiversity to revise protein domain models, evidence from innate immunity. Molecular Biology and Evolution, 38(12), (2021): 5806–5818, https://doi.org/10.1093/molbev/msab258.Sequence annotation is fundamental for studying the evolution of protein families, particularly when working with nonmodel species. Given the rapid, ever-increasing number of species receiving high-quality genome sequencing, accurate domain modeling that is representative of species diversity is crucial for understanding protein family sequence evolution and their inferred function(s). Here, we describe a bioinformatic tool called Taxon-Informed Adjustment of Markov Model Attributes (TIAMMAt) which revises domain profile hidden Markov models (HMMs) by incorporating homologous domain sequences from underrepresented and nonmodel species. Using innate immunity pathways as a case study, we show that revising profile HMM parameters to directly account for variation in homologs among underrepresented species provides valuable insight into the evolution of protein families. Following adjustment by TIAMMAt, domain profile HMMs exhibit changes in their per-site amino acid state emission probabilities and insertion/deletion probabilities while maintaining the overall structure of the consensus sequence. Our results show that domain revision can heavily impact evolutionary interpretations for some families (i.e., NLR’s NACHT domain), whereas impact on other domains (e.g., rel homology domain and interferon regulatory factor domains) is minimal due to high levels of sequence conservation across the sampled phylogenetic depth (i.e., Metazoa). Importantly, TIAMMAt revises target domain models to reflect homologous sequence variation using the taxonomic distribution under consideration by the user. TIAMMAt’s flexibility to revise any subset of the Pfam database using a user-defined taxonomic pool will make it a valuable tool for future protein evolution studies, particularly when incorporating (or focusing) on nonmodel species.This work was supported by The National Science Foundation (Grant No. IOS—1755377 to K.M.H., Rita Graze, and Elizabeth Hiltbold Schwartz), and K.T.D. was supported by The National Science Foundation’s Graduate Research Fellowship Program
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