Spatial Exploration of Multiple Cropping Efficiency in China Based on Time Series Remote Sensing Data and Econometric Model

This study explored spatial explicit multiple cropping efficiency （MCE） of China in 2005 by coupling time series remote sensing data with an econometric model - stochastic frontier analysis （SFA）. We firstly extracted multiple cropping index （MCI） on the basis of the close relationship between crop phenologies and moderate-resolution imaging spectroradiometer （MODIS） enhanced vegetation index （EVI） value. Then, SFA model was employed to calculate MCE, by considering several indicators of meteorological conditions as inputs of multiple cropping systems and the extracted MCI was the output. The result showed that 46% of the cultivated land in China in 2005 was multiple cropped, including 39% double- cropped land and 7% triple-cropped land. Most of the multiple cropped land was distributed in the south of Great Wall. The total efficiency of multiple cropping in China was 87.61% in 2005. Southwestern China, Ganxin Region, the middle and lower reaches of Yangtze River and Huanghuaihai Plain were the four agricultural zones with the largest rooms for increasing MCI and improving MCE. Fragmental terrain, soil salinization, deficiency of water resources, and loss of labor force were the obstacles for MCE promotion in different zones. The method proposed in this paper is theoretically reliable for MCE extraction, whereas further studies are need to be done to investigate the most proper indicators of meteorological conditions as the inputs of multiple cropping systems.

Spatiotemporal differences and influencing factors of multiple cropping index in China during 1998-2012

Raising the level of the multiple cropping index （MCI） plays a critical role in food production of China. Therefore, exploring the spatiotemporal differences and factors of the MCI in China is of important practical significance. This paper examines the trend of multiple cropping index （MCI） changes in China at the national, regional and provincial levels during 1998-2012. Based on the Theil index, this paper explores the spatiotemporal differences of the MCI in China. Additionally, a spatial econometric model is used to identify the determi- nants of the spatiotemporal differences of the MCI from a behavioral perspective. The results are summarized as follows： （1） From the national perspective, the MCI shows an increasing trend year by year, rising from 120.1% in 1998 to 134.26% in 2012; （2） at the regional level, the northeastern region is the fastest growing area in terms of MCI, whereas the central region is the slowest growing area. The central region has the highest MCI level, whereas the northeastern region is connected to the lowest MCI level; （3） according to the Theil index value, the differences in the MCI show a narrowing trend from 0.11 in 1998 to 0.03 in 2012, which is primarily attributed to the differences among the four regions; （4） the MCI shows differences among China＇s 31 provinces, and the gap that it shows is great; and （5） the proportion of non-agricultural population has a significant negative effect on the MCI. However, the proportions of non-agricultural industry, agricultural policy, per capita operating arable land area and rural household per capita net income have a significant positive impact on the MCI. Therefore, the following policies are suggested to increase the level of China＇s cultivated land MCI： transferring rural surplus labor, increasing the farmers＇ income, accelerating the transfer of the use rights of arable land, developing the scale effect of land use, providing further support and benefits to farmers in less developed regions and major grain-producing areas, and strengthening the role of the national agricultural policy.

Assessing human sperm morphology： top models, underdogs or biometrics？

The assessment of the percentage of spermatozoa having an ＇ideal＇ morphology using so-called strict method is the method recommended in the latest edition of the World Health Organization （WHO） laboratory manual for semen analysis. This recommendation is a result of the statistical association between ＇ideal＇ sperm morphology and fertility, and of the current general belief that sperm morphology assessment should be used primarily as a fertility tool. The notion of an ＇ideal＇ sperm morphology has persisted despite the very low percentage of such spermatozoa in the semen of fertile men, a subject of intense controversy. The detailed categorization of each abnormal spermatozoon has thus, for a long time, been considered optional and partially redundant, an idea which is reflected in the earlier editions of the WHO manual. However, several recent studies have shown the importance of carefully assessing abnormal sperm morphology for use in the diagnosis ＆infertility, to determine fertility prognosis, and for basic or public health studies. One approach, which combines videomicroscopy and computer vision, and is the only approach able to assess the continuum of sperm biometrics, has been used successfully in several recent clinical, basic and toxicology studies. In summary, the visual assessment of detailed sperm morphology--including the categorization of anomalies allowing arithmetically derived indices of teratozoospermia--and the more modern computer-based approaches, although often considered to be redundant, are in fact complementary. The choice of the most appropriate method depends on the field of investigation （clinical, research, toxicology） and the problem being addressed. Each approach has advantages as well as certain limitations, which will be discussed briefly herein.

High-Order Iterative Methods Repeating Roots a Constructive Recapitulation

This paper considers practical, high-order methods for the iterative location of the roots of nonlinear equations, one at a time. Special attention is being paid to algorithms also applicable to multiple roots of initially known and unknown multiplicity. Efficient methods are presented in this note for the evaluation of the multiplicity index of the root being sought. Also reviewed here are super-linear and super-cubic methods that converge contrarily or alternatingly, enabling us, not only to approach the root briskly and confidently but also to actually bound and bracket it as we progress.

The Multiplicative Zagreb Indices of Nanostructures and Chains

In theoretical chemistry, the researchers use graph models to express the structure of molecular, and the Zagreb indices and multiplicative Zagreb indices defined on molecular graph G are applied to measure the chemical characteristics of compounds and drugs. In this paper, we present the exact expressions of multiplicative Zagreb indices for certain important chemical structures like nanotube, nanostar and polyomino chain.

Analysis of Air Pollution Impact Factors in China： A MIMIC Modeling Approach

In this study, we investigate the impact factors on air pollution in terms of CO2, SO2 and NOx emissions simultaneously in China and compare changes in air pollution across provinces from 1998 to 2011 using a Multiple Indicators and Multiple Causes Model （MIMIC） within a Structural Equation Model （SEM） framework. Our findings reveal that GDP per capita and total population have the largest impacts on air pollution, followed by energy intensity, foreign direct investment, population density, and industrialization. The results also reveal that the inverted U-shaped Environmental Kuznets Curve （EKC） hypothesis exists in China. Our findings also demonstrate that Shandong, Jiangxi and Liaoning are the top three provinces with the most deteriorated air quality while Xinjiang, Fujian and Ningxia are with the best. These results not only contribute to advancing the existing literature, but also merit particular attention from policy-makers in China.

THREE KIRCHHOFFIAN INDICES OF THE CACTUS GRAPHS

In this paper we give six explicit formulae to compute the Kirchhoff index,the multiplicative degree-Kirchhoff index and the additive degree-Kirchhoff index of the k-cactus chain and the cactus graph which can be obtained from a k-cactus chain by expanding each of the cut-vertices to a cut edge.