Active random force promotes diffusion in bacterial cytoplasm

Experiments have found that diffusion in metabolically active cells is much faster than in dormant cells, especially for large particles. However, the mechanism of this size-dependent diffusion enhancement in living cells is still unclear. In this work, we approximate the net effect of metabolic processes as a white-noise active force and simulate a model system of bacterial cytoplasm with a highly polydisperse particle size distribution. We find that diffusion enhancement in active cells relative to dormant cells can be more substantial for large particles. Our simulations agree quantitatively with the experimental data of Escherichia coli, suggesting an autocorrelation function of the active force proportional to the cube of particle radius. We demonstrate that such a white-noise active force is equivalent to an active force of about 0.57 pN with random orientation. Our work unveils an emergent simplicity of random processes inside living cells.Comment: 20 pages, 18 figure

Tail Dependence for Regularly Varying Time Series

We use tail dependence functions to study tail dependence for regularly varying RV time series. First, tail dependence functions about RV time series are deduced through the intensity measure. Then, the relation between the tail dependence function and the intensity measure is established: they are biuniquely determined. Finally, we obtain the expressions of the tail dependence parameters based on the expectation of the RV components of the time series. These expressions are coincided with those obtained by the conditional probability. Some simulation examples are demonstrated to verify the results we established in this paper

Poly[μ4-succinato-μ2-succinato-bis[diamminecopper(II)]]

In the title compound, [Cu(C4H4O4)(NH3)2]n, the Cu atom is coordinated by the N atoms of two ammonia mol­ecules and four O atoms from three different succinate ligands in a highly distorted octa­hedral geometry. The Cu atom and the C and O atoms of the succinate ligands lie on a mirror plane. Two adjacent CuO4N2 octa­hedra share one common O–O edge, forming a Cu2O6N4 biocta­hedron with a Cu⋯Cu separation of 3.524 (2) Å. Neighboring biocta­hedra are connected by bis-unidentate succinate anions in the a-axis direction, while in the c-axis direction biocta­hedra are connected by bis-bidentate succinate anions, leading to an infinite two-dimensional network structure. These networks are further connected along the a-axis direction by hydrogen bonds between ammonia ligands and carboxyl­ate O atoms of neighboring network layers, forming a three-dimensional lamellar structure

Approximation for the Finite-Time Ruin Probability of a General Risk Model with Constant Interest Rate and Extended Negatively Dependent Heavy-Tailed Claims

We propose a general continuous-time risk model with a constant interest rate. In this model, claims arrive according to an arbitrary counting process, while their sizes have dominantly varying tails and fulfill an extended negative dependence structure. We obtain an asymptotic formula for the finite-time ruin probability, which extends a corresponding result of Wang (2008)

High Dose ESAs Are Associated with High iPTH Levels in Hemodialysis Patients with End-Stage Kidney Disease: A Retrospective Analysis

Objective: Anemia and secondary hyperparathyroidism are the two most common complications associated with chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs) are widely used in the management of anemia in hemodialysis patients. A reverse correlation has been established between hyperparathyroidism and hemoglobin levels. The aim of this retrospective study is to evaluate the relationship of high dose ESAs and hyperparathyroidism in hemodialysis patients with anemia. Methods: A total of 240 uremic patients maintained on regular hemodialysis were enrolled into this study. Among them, 142 patients were treated with Epiao® (epoetin-alfa) and 98 patients were treated with Recormon® (epoetin-beta). The target hemoglobin concentration was 110-130 g/L. Laboratory measurements including hemoglobin, calcium, phosphorus, albumin, intact-parathyroid hormone (iPTH), serum ferritin and transferrin saturation were collected. Results: Hemoglobin concentration increased as iPTH level decreased by stratification. However, no significant association between anemia and calcium or phosphorus level was found. Patients with iPTH levels within 150-300 pg/mL had the highest levels of hemoglobin, serum ferritin and transferrin saturation. Patients treated with Recormon and Epiao had similar hemoglobin concentrations. However, the dose of Recormon for anemia treatment was significantly less than that the dose of Epiao (P<0.05). The level of iPTH in the Recormon group was significantly lower than in the Epiao group. In patients with hemoglobin levels between 110-130 g/L (P<0.05), iPTH level was found to be significantly lower in patients treated with lower doses of ESAs than in patients treated with higher doses of ESAs, no matter which ESA was used (Recormon or Epiao, P<0.05). Conclusions: The dose of ESAs might be positively associated with iPTH level, suggesting that a reasonable hemoglobin target can be achieved by using the lowest possible ESA dose

Detection of Outliers and Patches in Bilinear Time Series Models

We propose a Gibbs sampling algorithm to detect additive outliers and patches of outliers in bilinear time series models based on Bayesian view. We first derive the conditional posterior distributions, and then use the results of first Gibbs run to start the second adaptive Gibbs sampling. It is shown that our procedure could reduce possible effects on masking and swamping. At last, some simulations are performed to demonstrate the efficacy of detection and estimation by Monte Carlo methods

On the strong laws for weighted sums of ρ∗-mixing random variables,”

Complete convergence is studied for linear statistics that are weighted sums of identically distributed ρ * -mixing random variables under a suitable moment condition. The results obtained generalize and complement some earlier results. A Marcinkiewicz-Zygmund-type strong law is also obtained