Activation Level and Probabilities of Electromagnetic γ-transitions in the Reaction 77Se(γ,γ’)77mSe

The dependence of the absolute yield from energies for reaction (γ,γ’)m on the nucleus 77Se was approximated by fit dependences (lines). Due to the visually detected fracture of the reaction yield, the energy interval 5.75-8.0 MeV is conventionally divided into two parts. For the transition step as one experimental point, the left part was approximated to 6.6 MeV, and the right part - from 6.26 MeV. There approximations were eight for both intervals. Given the features of the calculation and the minimum values for χ2, the "best" two fits are approximation dependences in the neighborhood of the intersection point x0 for the left and right arrays of energies. The energy for the activation level (the intersection point for these functions) is Ea≈6.35 MeV. The scheme of electromagnetic γ- transitions for nucleus 77Se are constructed and analyzed. Possible transitions to the isomeric level from higher levels are indicated. Weiskopf model was used to estimate the values of the reduced probabilities of electric EJ- and magnetic MJ- transitions, the probabilities of transitions per unit time and half-life. The theoretical values of the half-lives T1/2 are compared with the experimental data. Prospects for further use of the obtained results for topical problems of nuclear physics are discussed.

Molecular chaperones maximize the native state yield per unit time by driving substrates out of equilibrium

Molecular chaperones have evolved to facilitate folding of proteins and RNA in vivo where spontaneous self-assembly is sometimes prohibited. Folding of Tetrahymena ribozyme, assisted by the RNA chaperone CYT-19, surprisingly shows that at physiological Mg2+ ion concentrations, increasing the chaperone concentration reduces the yield of native ribozymes. In contrast, the more extensively investigated protein chaperone GroEL works in exactly the opposite manner—the yield of native substrate increases with the increase in chaperone concentration. Thus, the puzzling observation on the assisted-ribozyme folding seems to contradict the expectation that a molecular chaperone acts as an efficient annealing machine. We suggest a resolution to this apparently paradoxical behavior by developing a minimal stochastic model that captures the essence of the Iterative Annealing Mechanism (IAM), providing a unified description of chaperone mediated-folding of proteins and RNA. Our theory provides a general relation involving the kinetic rates of the system, which quantitatively predicts how the yield of native state depends on chaperone concentration. By carefully analyzing a host of experimental data on Tetrahymena (and its mutants) as well as the protein Rubisco and Malate Dehydrogenase, we show that although the absolute yield of native states decreases in the ribozyme, the rate of native state production increases in both the cases. By utilizing energy from ATP hydrolysis, both CYT-19 and GroEL drive their substrate concentrations far out of equilibrium, in an endeavor to maximize the native yield in a short time. Our findings are consistent with the general expectation that proteins or RNA need to be folded by the cellular machinery on biologically relevant timescales, even if the final yield is lower than what equilibrium thermodynamics would dictate. Besides establishing the IAM as the basis for functions of RNA and protein chaperones, our work shows that cellular copy numbers have been adjusted to optimize the rate of native state production of the folded states of RNA and proteins under physiological conditions.Significance statementMolecular chaperones have evolved to assist the folding of proteins and RNA, thus avoiding the deleterious consequences of misfolding. Thus, it is expected that increasing chaperone concentration should lead to an enhancement in native yield. While this has been observed in GroEL-mediated protein folding, experiments on Tetrahymena ribozyme folding assisted by CYT-19, surprisingly show the opposite trend. Here, we reconcile these divergent experimental observations by developing a unified stochastic model of chaperone assisted protein and RNA folding. We show that chaperones drive their substrates out of equilibrium, and in the process maximize the rate of native substrate production rather than the absolute yield or the folding rate. In vivo the number of chaperones is regulated to optimize their functions.

Uncertainties in global crop model frameworks: effects of cultivar distribution, crop management and soil handling on crop yield estimates

Global gridded crop models (GGCMs) combine field-scale agronomic models or sets of plant growth algorithms with gridded spatial input data to estimate spatially explicit crop yields and agricultural externalities at the global scale. Differences in GGCM outputs arise from the use of different bio-physical models, setups, and input data. While algorithms have been in the focus of recent GGCM comparisons, this study investigates differences in maize and wheat yield estimates from five GGCMs based on the public domain field-scale model Environmental Policy Integrated Climate (EPIC) that participate in the AgMIP Global Gridded Crop Model Intercomparison (GGCMI) project. Albeit using the same crop model, the GGCMs differ in model version, input data, management assumptions, parameterization, geographic distribution of cultivars, and selection of subroutines e.g. for the estimation of potential evapotranspiration or soil erosion. The analyses reveal long-term trends and inter-annual yield variability in the EPIC-based GGCMs to be highly sensitive to soil parameterization and crop management. Absolute yield levels as well depend not only on nutrient supply but also on the parameterization and distribution of crop cultivars. All GGCMs show an intermediate performance in reproducing reported absolute yield levels or inter-annual dynamics. Our findings suggest that studies focusing on the evaluation of differences in bio-physical routines may require further harmonization of input data and management assumptions in order to eliminate background noise resulting from differences in model setups. For agricultural impact assessments, employing a GGCM ensemble with its widely varying assumptions in setups appears the best solution for bracketing such uncertainties as long as comprehensive global datasets taking into account regional differences in crop management, cultivar distributions and coefficients for parameterizing agro-environmental processes are lacking. Finally, we recommend improvements in the documentation of setups and input data of GGCMs in order to allow for sound interpretability, comparability and reproducibility of published results.

Additional lime of CaO in rearing medium with salinity for growing of catfish Pangasius hypopthalmus

<p>Catfish juvenile quality improvements sought through the addition of lime to the availability of minerals in the body. Media maintenance is set at 4‰ salinity aims to reduce the level of osmotic work to reduce energy used for osmoregulation and can be allocated to the growth of catfish. Juvenile-sized fish used 2.59±0.02 cm and weights 0.13±0.01 g. Aquarium measuring 20×20×20 cm3 used 15 units, filled with water salinity of 4% as 6 L per unit, and added lime CaO appropriate treatment. During the study, the fish were fed with 28% protein content three times a day with FR 5%. Addition of CaO treatment dose 0 mg/L, 20 mg/L, 40 mg/L, 60 mg/L, 80 mg/L result in the survival rate of 100%, 100%, 100%, 96.29%, and 100% (p&gt;0.05). The growth rate of daily weight 5.196%, 5.212%, 6.596%, 5.35% and 5.101% (p&gt;0.05). Long absolute yield significantly different values are 1.451 cm, 1.518 cm, 1.964 cm, 1.71 cm, and 1.546 cm (p&lt;0.05). During the study, the water quality is within the range that can be tolerated by catfish juvenile. The use of lime in the salinity of 4% is suggested as many as 40 mg/L CaO with the turnover of water every day and feeding enough.</p><p>Keywords: CaO, salinity, growth, Pangasius hypopthalmus</p>

Comparison of the phosphate requirements of burr medic and yellow serradella with that of wheat in the low rainfall wheatbelt of Western Australia

The responses of burr medic (Medicago polymorpha) and yellow serradella (Ornithopus compressus) to topdressed phosphate were compared with the response of wheat (Triticum aestivum) to drilled phosphate on a range of soils in the low rainfall wheatbelt of Western Australia. Species were compared firstly on the amount of applied phosphorus (P) required for 90% maximum yield at 3 harvests, and secondly on the ratio of their curvature coefficients from the Mitscherlich relationship between absolute yield and P applied. On 7 marginally acidic, medium-textured soils, the comparative requirements of burr medic (cvv. Serena or Santiago) and wheat (cv. Gutha) for applied P changed with harvest. At harvest 1 152-55 days after sowing (DAS)], burr medic generally had a larger curvature coefficient and required less applied P for 90% maximum yield than wheat. At harvest 2 (107-111 DAS) and for harvest 3 (seed yields), the curvature coefficients for burr medic were smaller than those for wheat, and burr medic generally required more applied P at 90% maximum yield. The average P requirement at 90% maximum yield of burr medic was 14 kg P/ha at harvest 1, 22 kg P/ha at harvest 2, and 19 kg P/ha for seed production. The average P requirement of wheat was 28 kg P/ha at harvest 1,11 kg P/ha at harvest 2, and 15 kg P/ha for seed production. On 3 acidic, light-textured soils, yellow serradella (cv. Madeira) generally had a lower requirement for applied P at 90% maximum yield, and a larger curvature coefficient, than wheat (cv. Gutha) at all harvests in each experiment. The requirements of yellow serradella and wheat also varied between harvests. The average P requirement at 90% maximum yield of yellow serradella was 16 kg P/ha at harvest 1 (52-55 DAS), 21 kg P/ha at harvest 2 (105-110 DAS), and close to 26 kg P/ha for seed production. The average P requirement of wheat was 29 kg P/ha at harvest 1,25 kg P/ha at harvest 2, and >33 kg P/ha for seed production. In most experiments burr medic had a larger absolute response to applied P at harvests 1 and 2 and a lower absolute response for seed production than wheat. Yellow serradella had a smaller absolute yield response to applied P than wheat over all 3 harvests. When converted to a percentage of maximum yield, burr medic and yellow serradella had a lower percentage response to applied P at harvest 1, and a higher percentage response at harvest 2 and for seed production than wheat.