The Dimensions and Units of the Population Interaction Coefficients

We discuss the interpretation and dimensions of the population dynamic parameters that are commonly used to quantify the strength of intraspecific and interspecific interactions. The concept of “interaction strength” is not unequivocal. Its theoretical formalization relies on the generalized Lotka–Volterra model. However, four different ways of parameterizing the model have been proposed in the literature, leading to four different definitions of the term “interaction strength.” In particular, the dimensions of these four definitions are not identical, some of these incorporating explicitly the dimension used to measure the population size. Using an individual-based simulation model as an illustration, we show that, in the latter case, the interaction strength depends implicitly on the habitat size. As a consequence, it is of crucial importance to quantify the population as a density rather than an absolute population abundance. We insist that the dimension of the interaction strength coefficient should not be overlooked and any quantitative estimation must be given with explicit units.

Interactions Between Remimazolam and Propofol in Combination With Sufentanil for Anesthesia During Gastroscopy

Background This study was conducted to determine how remimazolam and propofol interact when given with sufentanil. Methods In this single-arm study, patients were assigned to one of five groups. The sample size was not determined in advance. When the median effective dose(ED50) and 95% confidence intervals were calculated, participants were stopped. The study included 159 patients who were scheduled for a gastrointestinal endoscopic examination and had an American Society of Anesthesiologists physical status of I/II. Patients were intravenously administered sufentanil (0.1 µg/kg), along with different doses of remimazolam and propofol depending on the group to which they were assigned. The endpoint for an effective response was the disappearance of the bilateral eyelash reflex. The up-and-down method was used to determine the ED50 within each treatment group. The ED50 deviations from the additive line were analyzed using isoradiometric analysis. The interaction coefficients were calculated by algebraic analysis. Interval estimation is used in statistical inference. Results In combination with sufentanil, the ED50 of remimazolam and propofol was determined to be 0.065 (0.057-0.074) mg/kg and 0.657 (0.590-0.724) mg/kg, respectively. After sufentanil administered, when 0.25, 0.5, and 0.75 ED50 remimazolam were given in combination with propofol, the interaction coefficients were 1.03,1.2and 1.08, respectively. Conclusions The dose of propofol with remimazolam may need to be reduced regardless of the additive or synergistic effect. There was a strong synergistic effect when the dose ratio of the two drugs was about 6:1 in mg/kg. Trial registration: The project was retrospectively registered on October 26, 2021 in Chinese clinical trial center with the registration number of ChiCTR2100052425.

Thermodynamics and Transport Properties

The fundamentals of thermodynamics are reviewed, focusing on the chemistry of high-temperature metals, oxides (slags), and salts. Thermochemical data are provided for important molten metals: the free energies of solution of alloy elements, and interaction coefficients. Standard free energies of reactions are also provided, so the reader may calculate important chemical equilibria. Example calculations are provided for the deoxidation of steel. The removal of sulfur and phosphorus are also described. The second half of the chapter considers fundamental aspects of important physical properties: viscosity, surface tension, diffusion, and thermal and electrical conductivity.

Thermodynamic properties of fission products in liquid bismuth

The thermodynamic properties of fission products in molten salt and liquid metal have a great influence on the disposal of nuclear waste in the nuclear fuel cycle industrial system. This paper attempts to extract useful thermodynamic information from the only few experimental activities of lanthanides (Ce, Pr, La) in liquid Bi at different temperatures. The molecular interaction volume model (MIVM) was adopted to model and predict some temperature-dependent thermodynamic functions, including activity, infinite dilute activity coefficient, and molar excess Gibbs energy. The minor average of Δ G ¯ error indicated that assuming εji − εii is a constant is reasonable. On this basis, the natural logarithm of the interaction coefficients and the natural logarithm of the infinite dilute activity coefficient of lanthanides (Ce, Pr, La) in the Bi-based metal melt, these two parameters, show the linear relationship with the reciprocal of temperature. The reasonable agreement of the modeled thermodynamic parameters with the existing experimental data verified that the MIVM is quite convenient and reliable, which can provide guidance for separating fission products from molten salt reactors.

Effect of suckling and weaning systems on age, weight at puberty, and some reproductive traits in Awassi sheep: تأثير نظم الرضاعة والفطام في العمر والوزن عند البلوغ الجنسي وبعض الصفات التناسلية في الأغنام العواسية

A flock of seventy-two Awassi ewes aged five years were used in this study to evaluate the effects of three suckling system (24, 15, 9) hours and two weaning system at the weight of (15 and 20) Kg on age, weight at puberty, scrotum circumference and size and some characteristics of semen of Awassi lambs. Suckling and weaning systems had a significant effect (p≤0.05) on age and weight at puberty for males and the benefit of the suckling group for 24 hours and the weaning system of 20 kg. At 5 and 6 months of age, the suckling system had a significant effect (p≤0.05) on the circumference and size of the scrotum. At 6,7 and 8 months, the influence of the weaning system on the circumference and size of the scrotum, with the superiority of the suckling group 24 hours and the weaning system of 20 kg, a gradual and significant increase (p≤0.05) in the circumference and size of the scrotum was observed with age, and a significant improvement (p≤0.05) was observed in the characteristics of semen as the measurement period progresses. The lambs in the 24-hour suckling group gave the best semen consistency at puberty and after 4 weeks of puberty, and the 24-hour suckling group was superior than suckling group 9 hours in individual motility of sperm at puberty, and the interaction coefficients had a significant effect on age, weight at puberty, circumference and size of the scrotum at 5,6-and 7- months of age. The interaction between treatment effect on the size of semen in the second collection after puberty and its consistency at puberty also at the second collection the interaction had a significant effect (p≤0.05) on the individual and mass motility of the sperms at puberty and in the mass motility on the second collection of semen. Suckling and weaning systems had no significant effect on age and weight at puberty for female except for the superiority of the second interaction treatment on the third in weight at puberty which reached 37.88 and 27.80 kg respectively. The aim of this study was to find out the effect of suckling and weaning system for reaching sexual puberty and determining the age and weight at puberty in male and female Awassi sheep in addition to their effect on the circumference and size of the testicle and some of the semen characteristics of lambs, which are important characteristics for raising reproductive efficiency of the flock. The study recommends following the 24-hour suckling system and 20 kg weaning system, which leads to approach male lambs at a lower age and higher weight at sexual puberty.

Disentangling key species interactions in diverse and heterogeneous communities: A Bayesian sparse modeling approach

Modeling species interactions in diverse communities traditionally requires a prohibitively large number of species-interaction coefficients, especially when considering environmental dependence of parameters. We implemented Bayesian variable selection via sparsity-inducing priors on non-linear species abundance models to determine which species-interactions should be retained and which can be represented as an average heterospecific interaction term, reducing the number of model parameters. We evaluated model performance using simulated communities, computing out-of-sample predictive accuracy and parameter recovery across different input sample sizes. We applied our method to a diverse empirical community, allowing us to disentangle the direct role of environmental gradients on species' intrinsic growth rates from indirect effects via competitive interactions. We also identified a few neighboring species from the diverse community that had non-generic interactions with our focal species. This sparse modeling approach facilitates exploration of species-interactions in diverse communities while maintaining a manageable number of parameters.

Learning epistatic gene interactions from perturbation screens

The treatment of complex diseases often relies on combinatorial therapy, a strategy where drugs are used to target multiple genes simultaneously. Promising candidate genes for combinatorial perturbation often constitute epistatic genes, i.e., genes which contribute to a phenotype in a non-linear fashion. Experimental identification of the full landscape of genetic interactions by perturbing all gene combinations is prohibitive due to the exponential growth of testable hypotheses. Here we present a model for the inference of pairwise epistatic, including synthetic lethal, gene interactions from siRNA-based perturbation screens. The model exploits the combinatorial nature of siRNA-based screens resulting from the high numbers of sequence-dependent off-target effects, where each siRNA apart from its intended target knocks down hundreds of additional genes. We show that conditional and marginal epistasis can be estimated as interaction coefficients of regression models on perturbation data. We compare two methods, namely glinternet and xyz, for selecting non-zero effects in high dimensions as components of the model, and make recommendations for the appropriate use of each. For data simulated from real RNAi screening libraries, we show that glinternet successfully identifies epistatic gene pairs with high accuracy across a wide range of relevant parameters for the signal-to-noise ratio of observed phenotypes, the effect size of epistasis and the number of observations per double knockdown. xyz is also able to identify interactions from lower dimensional data sets (fewer genes), but is less accurate for many dimensions. Higher accuracy of glinternet, however, comes at the cost of longer running time compared to xyz. The general model is widely applicable and allows mining the wealth of publicly available RNAi screening data for the estimation of epistatic interactions between genes. As a proof of concept, we apply the model to search for interactions, and potential targets for treatment, among previously published sets of siRNA perturbation screens on various pathogens. The identified interactions include both known epistatic interactions as well as novel findings.