Epidemic modelling by ripple-spreading network and genetic algorithm

Mathematical analysis and modelling is central to infectious disease epidemiology. This paper, inspired by the natural ripple-spreading phenomenon, proposes a novel ripple-spreading network model for the study of infectious disease transmission. The new epidemic model naturally has good potential for capturing many spatial and temporal features observed in the outbreak of plagues. In particular, using a stochastic ripple-spreading process simulates the effect of random contacts and movements of individuals on the probability of infection well, which is usually a challenging issue in epidemic modeling. Some ripple-spreading related parameters such as threshold and amplifying factor of nodes are ideal to describe the importance of individuals’ physical fitness and immunity. The new model is rich in parameters to incorporate many real factors such as public health service and policies, and it is highly flexible to modifications. A genetic algorithm is used to tune the parameters of the model by referring to historic data of an epidemic. The well-tuned model can then be used for analyzing and forecasting purposes. The effectiveness of the proposed method is illustrated by simulation results

Consumer debt delinquency by family lifecycle categories

Postprint.Purpose: The purpose of this paper is to document debt delinquency patterns by family lifecycle categories using multiple data sets that are nationally representative of American families. Findings: The results show that among the 15 household lifecycle categories, the top three most likely to be delinquent are young couples with children aged seven or older, middle-aged singles with children aged 15 or older, and middle-aged singles with children under 15. Younger households are more financially distressed than their older counterparts. Presence of children increases the probability of debt delinquency.Includes bibliographical references

Effects of Age on Saving Motives of Chinese Urban Consumers

Prior research on the saving behavior of Chinese consumers gave indirect evidence of various saving motives. In contrast, this study examined saving motives directly reported by consumers in a national survey in China. Findings indicated that the three most commonly reported motives were saving for emergency, children’s education, and retirement. Mediation analysis results suggested that saving motives reported by Chinese survey participants had clear life cycle patterns

N-{N-[N-(1,1-Dimethyl­ethoxy­carbon­yl)-l-leuc­yl]-N-methyl-l-leuc­yl}-N-methyl-l-leucine benzyl ester

The tripeptide title compound, C32H53N3O6, synthesized in 80% yield by coupling of N-methyl-l-leucine benzyl ester with tert-butoxy­carbonyl-l-leucyl-N-methyl-l-leucine at 273 K, conjugates through two amide linkages and includes two protecting groups: a tert-butyl­oxycarbonyl group at the C-tip and a benzyl group at the N-tip. A classical inter­molecular N—H⋯O hydrogen bond and a weak non-conventional inter­molecular C—H⋯O contact connect the mol­ecules, forming layers parallel to (001)

2-Amino-3,4,5,6-tetra­fluoro­benzoic acid

The asymmetric unit of the title compound, C7H3F4NO2, obtained as an inter­mediate in the synthesis of a coupling reagent, contains four independent and conformationally similar mol­ecules. The amine H atoms form both intra­molecular and inter­molecular N—H⋯Ocarbox­yl hydrogen bonds which, together with inter­molecular O—H⋯Ocarbox­yl hydrogen bonds and N—H⋯F associations form ribbon structures along the a axis

Linezolid and Rifampicin Combination to Combat cfr-Positive Multidrug-Resistant MRSA in Murine Models of Bacteremia and Skin and Skin Structure Infection.

Linezolid resistance mediated by the cfr gene in MRSA represents a global concern. We investigated relevant phenotype differences between cfr-positive and -negative MRSA that contribute to pathogenesis, and the efficacy of linezolid-based combination therapies in murine models of bacteremia and skin and skin structure infection (SSSI). As a group, cfr-positive MRSA exhibited significantly reduced susceptibilities to the host defense peptides tPMPs, human neutrophil peptide-1 (hNP-1), and cathelicidin LL-37 (P < 0.01). In addition, increased binding to fibronectin (FN) and endothelial cells paralleled robust biofilm formation in cfr-positive vs. -negative MRSA. In vitro phenotypes of cfr-positive MRSA translated into poor outcomes of linezolid monotherapy in vivo in murine bacteremia and SSSI models. Importantly, rifampicin showed synergistic activity as a combinatorial partner with linezolid, and the EC50 of linezolid decreased 6-fold in the presence of rifampicin. Furthermore, this combination therapy displayed efficacy against cfr-positive MRSA at clinically relevant doses. Altogether, these data suggest that the use of linezolid in combination with rifampicin poses a viable therapeutic alternative for bacteremia and SSSI caused by cfr-positive multidrug resistant MRSA

Methyl 2-amino-3,4,5,6-tetra­fluoro­benzoate

In the title compound, C8H5F4NO2, synthesized by esterification of 2,3,4,5-tetra­fluoro­anthranilic acid with methanol, an intra­molecular amine N—H⋯Ocarbon­yl hydrogen bond is present, while inter­molecular N—H⋯O hydrogen bonds produce chains in the crystal, which extend along the b-axis direction

Analysis of Soil-Structure Interaction with Finite Element Method

Abstract. Analysis of dynamic behavior of soil-structure interaction (SSI) is a complicated problem due to the complexities of soil behaviors and dynamic analysis. It is difficult to solve SSI with analytical methods. However, numerical methods with highly developed computer technique are efficient. Based on the advanced nonlinear finite element analysis software MSC.Marc, SSI on loess ground is studied. An approach for the application of MSC.Marc in SSI analysis is presented and an example is given. Hyperbolic soil constitutive relationship and viscous boundary conditions are adopted in the soil model. Moreover, contact between the embedded columns and the adjacent soil is considered. Response spectrum analysis of the result is carried out. Some conclusions about the seismic response of soil-structure system under different soil stiffness and different soil-layer thickness conditions are given. A new way of analyzing SSI for loess ground is provided