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A novel approach was developed for predicting the structural classes of proteins based on their sequences. It was assumed that proteins belonging to the same structural class must bear some sort of similar texture on the images generated by the cellular automaton evolving rule [Wolfram, S., 1984. Cellular automation as models of complexity. Nature 311, 419-424]. Based on this, two geometric invariant moment factors derived from the image functions were used as the pseudo amino acid components [Chou, K.C., 2001. Prediction of protein cellular attributes using pseudo amino acid composition. Proteins: Struct., Funct., Genet. (Erratum: ibid., 2001, vol. 44, 60) 43, 246-255] to formulate the protein samples for statistical prediction. The success rates thus obtained on a previously constructed benchmark dataset are quite promising, implying that the cellular automaton image can help to reveal some inherent and subtle features deeply hidden in a pile of long and complicated amino acid sequences. 相似文献
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Sangrak Kim 《Molecular simulation》2013,39(11):906-911
Work–energy theorem is examined for nanodroplets collisions in molecular dynamics simulations. Work term and energy term in the work–energy theorem are separately calculated and the equality between them is checked. The terms are based on different microscopic variables. A serious mismatch between them is observed. Therefore, we have to pay attention to calculating some physical quantities related to the work–energy theorem, in particular, for the non-equilibrium properties of nanosystems. This seems to be due to cut-off radius of the potential and a subtraction of two large quantities that are nearly the same. Furthermore, Hurst exponents H are calculated to characterise the time series of the powers for the work term and they change significantly with samplings of the corresponding time series for the case of mismatch. 相似文献
15.
Ronan James O'Sullivan Tutku Aykanat Susan E. Johnston Adam Kane Russell Poole Ger Rogan Paulo A. Prodhl Craig R. Primmer Philip McGinnity Thomas Eric Reed 《Ecology and evolution》2019,9(12):7096-7111
Comparing observed versus theoretically expected evolutionary responses is important for our understanding of the evolutionary process, and for assessing how species may cope with anthropogenic change. Here, we document directional selection for larger female size in Atlantic salmon, using pedigree‐derived estimates of lifetime reproductive success as a fitness measure. We show the trait is heritable and, thus, capable of responding to selection. The Breeder's Equation, which predicts microevolution as the product of phenotypic selection and heritability, predicted evolution of larger size. This was at odds, however, with the observed lack of either phenotypic or genetic temporal trends in body size, a so‐called “paradox of stasis.” To investigate this paradox, we estimated the additive genetic covariance between trait and fitness, which provides a prediction of evolutionary change according to Robertson's secondary theorem of selection (STS) that is unbiased by missing variables. The STS prediction was consistent with the observed stasis. Decomposition of phenotypic selection gradients into genetic and environmental components revealed a potential upward bias, implying unmeasured factors that covary with trait and fitness. These results showcase the power of pedigreed, wild population studies—which have largely been limited to birds and mammals—to study evolutionary processes on contemporary timescales. 相似文献
16.
《Structure (London, England : 1993)》2020,28(2):259-269.e8
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17.
An approach to automatic prediction of the amino acid type from NMR chemical shift values of its nuclei is presented here, in the frame of a model to calculate the probability of an amino acid type given the set of chemical shifts. The method relies on systematic use of all chemical shift values contained in the BioMagResBank (BMRB). Two programs were designed, one (BMRB stats) for extracting statistical chemical shift parameters from the BMRB and another one (RESCUE2) for computing the probabilities of each amino acid type, given a set of chemical shifts. The Bayesian prediction scheme presented here is compared to other methods already proposed: PROTYP RESCUE and PLATON and is found to be more sensitive and more specific. Using this scheme, we tested various sets of nuclei. The two nuclei carrying the most information are C(beta) and H(beta), in agreement with observations made in Grzesiek and Bax, 1993. Based on four nuclei: H(beta), C(beta), C(alpha) and C', it is possible to increase correct predictions to a rate of more than 75%. Taking into account the correlations between the nuclei chemical shifts has only a slight impact on the percentage of correct predictions: indeed, the largest correlation coefficients display similar features on all amino acids. 相似文献
18.
State dependent behavior and the Marginal Value Theorem 总被引:9,自引:5,他引:4
The Marginal Value Theorem (MVT) is the dominant paradigm inpredicting patch use and numerous tests support its qualitativepredictions. Quantitative tests under complex foraging situationscould be expected to be more variable in their support becausethe MVT assumes behavior maximizes only net energy-intake rate.However across a survey of 26 studies, foragers rather consistently"erred" in staying too long in patches. Such a consistent directionto the errors suggests that the simplifying assumptions ofthe MVT introduce a systematic bias rather than just imprecision.
Therefore, I simulated patch use as a state-dependent responseto physiological state, travel cost, predation risk, prey densities,and fitness currencies other than net-rate maximization (e.g.,maximizing survival, reproductive investment, or mating opportunities).State-dependent behavior consistently results in longer patchresidence times than predicted by the MVT or another foragingmodel, the minimize µ/g rule, and these rules fail to
closely approximate the best behavioral strategy over a widerange of conditions. Because patch residence times increasewith state-dependent behavior, this also predicts mass regulationbelow maximum energy capacities without direct mass-specificcosts. Finally, qualitative behavioral predictions from theMVT about giving-up densities in patches and the effects oftravel costs are often inconsistent with state-dependent behavior.Thus in order to accurately predict patch exploitation patterns,the model highlights the need to: (1) consider predator behavior(sit-and-wait versus actively foraging); (2) identify activitiesthat can occur simultaneously to foraging (i.e., mate searchor parental care); and (3) specify the range of nutritional
states likely in foraging animals. Future predictive modelsof patch use should explicitly consider these parameters. 相似文献
19.
Zacher R 《Journal of mathematical biology》2001,42(6):507-531
Conditions on the vital rates and the mating function are derived which imply existence or nonexistence of exponentially growing persistent age-distributions for age-dependent pair-formation models. 相似文献
20.
关于极限定理的一个新结果 总被引:1,自引:1,他引:0
设{X_n,n≥0}是可列非齐次马氏链,S_n(i_1,…,i_m,w)表示m元状态序组(i_1,…,i_m)在序列(X_1,…,X_m),(X_2,…,X_m 1)…,(X_n,…,X_n m-1)中出现的次数.本文通过利用{X_n,n≥O}在Wiener概率空间的一种实现,给出了关于S_n(i_1,…,i_m,w)的一个对任意可列非齐次马氏链普遍成立的强级限定理. 相似文献