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Some sufficient conditions ensuring that the subdirect sum of p-norm strictly diagonally dominant [or, for short, SDD(p)] matrices is in the class of SDD(p) matrices, are given. In particular, it is shown that the subdirect sum of overlapping principal submatrices of an SDD(p) matrix is also an SDD(p) matrix. Some examples are also given that illustrate the conditions presented. [ABSTRACT FROM AUTHOR]

Bacteria are an essential part of the microbial loops and play key roles in carbon cycling. To understand their ecological contributions in polar regions, they were measured in the northwest Weddell Sea during the 32nd Chinese National Antarctic Research Expedition in the austral summer of 2016. The results showed a range of bacterial abundance from 0.20 to 3.34 × 108 cells/L with an average of 1.03 × 108 cells/dm3. Bacterial production varied between 0.06 and 2.42 mg C/(m3 d) with an average of 0.44 mg C/(m3 d). Bacterial carbon budgets were unevenly distributed in the northwest Weddle Sea, and surpluses appeared in the autotrophic area such as Weddell Surface Water and Transitional Zonal Water with Weddell Sea influence (TWW), and deficits in the Weddell-Scotia Confluence (heterotrophic area). A t-test result suggested that the unbalanced bacterial carbon budgets were mainly caused by distributions of Chl a. Bacterial abundance was uncorrelated with environmental and biological factors in the autotrophic region. At the same time, production was positively correlated with temperature and Chl a. In the heterotrophic area, bacterial abundance was positively correlated with temperature. Production was significantly positively correlated with temperature, and Chl a. Bacterial production had a small contribution to the increase of bacterial abundance because of a strong top-down control in the northwest Weddell Sea. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers (CNFs) have received wide attention in recent years. However, the performance degradation of CNFs has become a serious problem restricting their development when exposed to hygrothermal environments. While most studies have attributed the degradation behaviour to the water susceptibility of CNFs, the internal mechanism and detailed performance evolution are seldom reported at the molecular level. This paper used molecular dynamics simulation to study the effects of moisture on the diffusion, structure, mechanical strength, and chemical stability of CNFs. Simulation results indicated that the water diffusivity in amorphous cellulosewas10 times higher than in crystalline cellulose, demonstrating the preferential water uptake in amorphous cellulose. Meanwhile, the diffusion coefficient of water was found to be almost constant in the amorphous cellulose with less than 5% moisture. This behaviour was related to the amount and size of pores in amorphous cellulose. Furthermore, under high humidity, there was a significant decrease in mechanical strength and chemical stability of amorphous cellulose. However, in the range 0–5.0% of water absorption, the mechanical performance showed a slight increase, and chemical stability was also relatively high. These results provide a crucial point (<5 wt% moisture) for CNFs to remain stable under hygrothermal environments. [ABSTRACT FROM AUTHOR]

The spatial scan statistic method has been widely used for detecting disease clusters. Its results may be affected by scales, including the aggregation level of the input data and the population threshold used in the detection. Previous studies offered inconsistent findings, and few had considered both types of scales at the same time. Using 24 simulated datasets and two real disease datasets, we investigated the method's sensitivity to the two types of scales. We aggregated the individual-level data into areal units of three levels, including county, town, and a 900 m grid. We detected clusters with three population thresholds, including 10%, 25%, and 50%. We used two measurements, distance between cluster centres and the Jaccard index, to quantify the consistency of clusters detected with different scale settings. We find: (1) the method is not greatly sensitive to the data aggregation level when the cluster is strong and in a place with high population density; (2) the method's sensitivity to the population threshold is determined by the actual size of the true cluster; and (3) a regular grid with fine resolution is advantageous over the subjectively defined areal units. The process and findings may have broader meanings to similar spatial analyses. [ABSTRACT FROM AUTHOR]

Traditional epidemic models of communicable diseases focus on the temporal dimension. We propose a framework for the epidemic forest approach to spatializing epidemic modeling. An epidemic forest is formed by epidemic trees, each using the tree structure to represent an epidemic starting from a primary case. Each node on the tree represents an individual case, and each link represents a parent–child transmission linkage and can be modeled with the spatiotemporal and other information about the cases. Structural, spatiotemporal, and epidemiological information can be extracted from constructed trees to characterize the epidemic they represent and to correspond to environmental data. When multiple primary cases can be determined, the forest is ready to build. We applied this method to the 2013 dengue fever epidemic in Guangzhou City, China. With the constructed forest, we particularly calculated the case reproduction ratio (Rt), an index widely used for characterizing epidemics, at the global, tree-wise, and pixel-wise scales. We further calculated correlation coefficients between these Rts and climate variables. Rts at different scales, as well as their associations with climate variables, offer information at different levels that is all important in epidemiological studies and disease control practices. Through this study, we explored and demonstrated how to spatialize epidemic modeling, what information can be extracted from this spatialization, and then how to use the extracted information. We also point out that spatialization of Rt is the essential process of mapping a communicable disease, corresponding to the spatialization of incidence or prevalence in mapping a chronic disease. [ABSTRACT FROM AUTHOR]

A novel protein molecularly imprinted microsphere with three-dimensionally ordered macroporous (3DOM) structure has been successfully prepared with a combination of colloidal crystal template method and molecular imprinting technique by using bovine serum albumin as template, acrylamide as functional monomer, and N,N′-methylenebisacrylamide as crosslinker, respectively. SEM shows that the polymeric microspheres have a highly ordered three-dimensional interconnected macroporous structure with typical face-centered cubic lattice. The isothermal and kinetic adsorption behaviors of the polymer were investigated. Compared with the traditional bulk polymer, the 3DOM imprinted microspheres show higher binding rate constant, adsorption capability and specificity to template molecules. [ABSTRACT FROM AUTHOR]

5d Solid-state oxides K0.84OsO3 (Os5.16+; 5d2.84) and Bi2.93Os3O11 (Os4.40+; 5d3.60) were synthesized under high-pressure and high-temperature conditions (6 GPa and 1500–1700 °C). Their crystal structures were determined by synchrotron x-ray diffraction and their 5d electronic properties and tunnel-like structure motifs were investigated. A KSbO3-type structure with a space group of Im-3 and Pn-3 was determined for K0.84OsO3 and Bi2.93Os3O11, respectively. The magnetic and electronic transport properties of the polycrystalline compounds were compared with those obtained theoretically. It was revealed that the 5d tunnel-like structures are paramagnetic with metallic charge conduction at temperatures above 2 K. This was similar to what was observed for structurally relevant 5d oxides, including Bi3Re3O11 (Re4.33+; 5d2.66) and Ba2Ir3O9 (Ir4.66+; 5d4.33). The absence of long-range magnetic order seems to be common among 5d KSbO3-like oxides, regardless of the number of 5d electrons (between 2.6 and 4.3 per 5d atom). [ABSTRACT FROM AUTHOR]