Note on minimally kk-rainbow connected graphs

An edge-colored graph $G$, where adjacent edges may have the same color, is {\it rainbow connected} if every two vertices of $G$ are connected by a path whose edge has distinct colors. A graph $G$ is {\it $k$-rainbow connected} if one can use $k$ colors to make $G$ rainbow connected. For integers $n$ and $d$ let $t(n,d)$ denote the minimum size (number of edges) in $k$-rainbow connected graphs of order $n$. Schiermeyer got some exact values and upper bounds for $t(n,d)$. However, he did not get a lower bound of $t(n,d)$ for $3\leq d<\lceil\frac{n}{2}\rceil$. In this paper, we improve his lower bound of $t(n,2)$, and get a lower bound of $t(n,d)$ for $3\leq d<\lceil\frac{n}{2}\rceil$.Comment: 8 page

Power scaling of high-power linearly polarized fiber lasers with <10 GHz linewidth

In this work, an all-fiberized polarization-maintained (PM) fiber laser has been demonstrated with a near-top-hat-shaped spectrum. By optimizing the modulation signal to generate near-top-hat-shaped spectrums, a 3-kW PM fiber laser has been achieved at &lt;10 GHz linewidth with the polarization extinction ratio of 96% and beam quality of 1.156, which is the highest output power ever reported with approximately 10 GHz linewidth, and further scaling of output power is limited by stimulated Brillouin scattering. By decomposing the mode content, the proportion of the fundamental mode in the output laser is above 97%. The stimulated Raman scattering suppression ratio reaches 62 dB at the maximal output power

Factors That Influence the Livelihood Resilience of Flood Control Project Resettlers: Evidence from the Lower Yellow River, China

Land requisition and resettlement of migrants are two major parts of flood control projects. After a large land area was allocated for flood control projects, livelihood resilience of resettlers became a great challenge. In this paper, Puyang County, Taiqian County, and Fan County, Henan Province, China, are chosen for a household survey. An index system to assess farming households&rsquo; livelihood resilience is constructed. After that, regression analysis and variance analysis are adopted to examine influencing factors of resettlers&rsquo; livelihood resilience. Results suggest the following: (1) Livelihood resilience of resettled farming households is on the whole lower than that of non-resettled farming households; (2) Response to policies, family scale, livelihood strategy, and skill training are major influencing factors of resettled farming households&rsquo; livelihood resilience; (3) Compared with other types of farming households, livelihood resilience of farming households with land expropriated is significantly different. In order to enhance resettlers&rsquo; livelihood resilience, the government should expand the application scope of follow-up support policies of reservoir resettlement, enhance capability construction of resettlement management departments, strengthen support for resettlers&rsquo; employment, combine resettlement with rural revitalization strategy, and improve the social security system for flood control project resettlers

Asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering for stability comparison of virus-like particles in different solution environments

The stabilities of two commercially available virus like particles, CHO-HBsAg expressed by Chinese hamster ovary (CHO) cells and Hans-HBsAg expressed by Hansenula polymorpha (Hans), were compared using AF4-MALLS under different treatment processes. The initial molecular weight and hydrodynamic diameter of CHO-HBsAg measured with AF4-MALLS were 4727 kDa and 29.4nm, while those of Hans-HBsAg were 3039 kDa and 22.8 nm respectively. In salt solution of 2 M ammonium sulfate, the molecular weight and size of CHO-HBsAg had little change, and its antigenicity remained 95%, while those of Hans-HBsAg changed greatly, resulting in aggregation and 75% antigenicity loss. In freeze-thaw operations, Hans-HBsAg aggregated heavily. Most of the aggregates precipitated and the rest soluble aggregates reached 10(5)-10(6) kDa in molecular weight. The antigenicity of Hatis-HBsAg decreased to 26.9% after five freeze-thaw cycles. For CHO-HBsAg, there was no obvious aggregation in freeze-thaw, and the antigenicity retained above 98%. In heating process, Hans-HBsAg gradually aggregated to large particles with temperature and the antigenicity decreased to 10% when the temperature reached 80 degrees C. In contrast, CHO-HBsAg would not aggregate with temperature, remained 92% antigenicity at 80 degrees C. The study demonstrated that CHO-HBsAg appeared to be a superior vaccine antigen in term of particle stability and constant antigenicity, which are important in production, transportation and storage. (C) 2016 Elsevier Ltd. All rights reserved

The Places–People Exercise: Understanding Spatial Patterns and the Formation Mechanism for Urban Commercial Fitness Space in Changchun City, China

The fitness industry is rapidly developing due to the demand for fitness activities, and a large number of commercial fitness spaces have emerged in Changchun city. The distribution of commercial fitness spaces in the city is not chaotic; different types of fitness spaces should have different spaces to choose from. The purpose of this article is to summarize the spatial distribution characteristics and laws of urban commercial fitness spaces, to help better develop commercial fitness spaces. Using Changchun (a central city in northeastern China) as an example, the article divides commercial fitness spaces into five categories. Then, GIS tools are used to analyze the distribution patterns, level distributions, and agglomeration characteristics of commercial fitness spaces. The city’s commercial fitness space distribution patterns are subjected to further study, along with the influencing factors and forming mechanisms of the pattern. Moreover, based on the research results, this study provides targeted suggestions for the development of fitness spaces. The study found that the commercial fitness space in Changchun city has formed a multi-core spatial pattern. Various types of fitness spaces show significant spatial differentiation in many aspects, such as “center-periphery” characteristics, the spatial distribution form, and the specialized characteristics of each block unit. Fitness needs, national policies, transportation accessibility, spatial agglomeration, land rent, urban population distribution, etc., are the main factors affecting the spatial distributions of fitness spaces

Mismatch analysis of all-fiber coherent beam combiners based on the self-imaging effect

All-fiber coherent beam combiners based on the self-imaging effect can achieve a near-perfect single laser beam, which can provide a promising way to overcome the power limitation of a single-fiber laser. One of the key points is combining efficiency, which is determined by various mismatches during fabrication. A theoretical model has been built, and the mismatch error is analyzed numerically for the first time. The mismatch errors have been numerically studied with the beam quality and combining efficiency being chosen as the evaluation criteria. The tolerance of each mismatch error for causing 1% loss is calculated to guide the design of the beam combiners. The simulation results are consistent with the experimental results, which show that the mismatch error of the square-core fiber is the main cause of the efficiency loss. The results can provide useful guidance for the fabrication of all-fiber coherent beam combiners