BackgroundThere are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-a-minute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m2 plots.ResultsIn monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P < 0.05). The relative yield (RY) of mile-a-minute and sweet potato was less than 1.0 in mixed culture, indicating that intraspecific competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P < 0.05) in mile-a-minute monoculture soil than in sweet potato monoculture soil, and were reduced by the competition of sweet potato in the mixture.ConclusionsEvidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet potatoes. This study also shows the potential value of replacement control methods which may apply to other crop-weed systems or invaded natural ecosystems.

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BackgroundNu people are the least populous ethnic group in Yunnan Province of China and most are distributed in Gongshan County, NW Yunnan. Animal production plays an important role in Nu livelihoods and the Nu people have abundant traditional knowledge of animal management and ethnoveterinary practices. This study documents the animal diseases, ethnoveterinary plant remedies and related traditional knowledge in three Nu villages of Gongshan County.MethodsThis study was carried out in three Nu villages of Gongshan County between July 2009 and February 2010. Data was obtained through the use of semi-structured questionnaires, field observation and PRA tools. A total of 60 Nu respondents (34 men and 26 women) provided information on animal ailments and ethnoveterinary plant medicines used for Nu livestock production. Information on traditional ethnoveterinary medicine knowledge and choice of treatment providers was also obtained.ResultsThirty-five animal conditions were identified in the surveyed area. The major and most common animal diseases among livestock were skin conditions, diarrhea, heat, fevers, colds, and parasites. Most ailments occurred between June and August. The ethnoveterinary medicinal use of 45 plant species was documented. Most medicinal species (86.7%) were collected from the wild. The most frequently used plant parts were whole plants (35.6%), followed by roots (22.2%). The most important medicinal plant species were Saussurea costus (Falc.) Lipech. (UV = 0.67), Senecio scandens Buch.-Ham.ex D.Don (UV = 0.67), Plantago depressa Willd. (UV = 0.63), Rubus corchorifolius L. f. (UV = 0.62), Bupleurum yunnanense Franch. (UV = 0.60), and Polygonum paleaceum Wall. (UV = 0.60). Animal diseases treated with the highest number of ethnoveterinary plant remedies were diarrhea (16 plant species), heat, fever, colds (11 plant species), retained afterbirth (11 plant species), and skin conditions and sores (11 plant species). Many Nu villagers (52%) considered traditional remedies their first choice of animal disease treatment. Traditional ethnoveterinary knowledge was related to the local social-cultural characteristics of Nu people and communities.ConclusionAnimal production plays an important role in Nu culture and livelihoods, and the Nu ethnic group has abundant traditional knowledge about animal production and ethnoveterinary plant remedies. This traditional knowledge faces the risk of disappearing due to increasing modern veterinary medicine extension, livelihood changes and environment degradation. Animal diseases are a major constraint in livestock production in Nu villages. Thus, some strategies and measures should be adopted in the future, such as further researches on Nu culture and livelihoods, community-based validation of ethnoveterinary medicine and broad network building and knowledge sharing.

For 30 diamond- and zincblende-structure semiconductors, the bond length d, bond polarity alpha p, bulk modulus B, elastic shear constants (c11-c12)/2 and c44, bond-stretching force constant alpha , bond-bending force constant beta , internal displacement parameter zeta , effective atomic charge Z*, transfer parameter beta *, transverse charge eT*, and piezoelectric charge ep* are calculated from bond orbital calculations based on the tight-binding method. The results are compared with previous theoretical calculations and experiments.

This paper reported on a study of using blogs as out-of-class assignments for the development of learners' writing competence. There were 36 students of English majors from an intact second language (L2) writing class participating in this study. A mixed method design was employed to obtain both quantitative and qualitative data. The results showed that blog-based peer feedback had a statistically significant positive correlation with learners' motivation, collaboration, and course satisfaction. The findings also revealed that the feedback was conducive to learners' self-reflection and self-confidence in L2 writing and could give rise to an enhanced L2 writing experience. The study concludes that group collaborative writing via blogging can not only encourage collaboration and self-reflection but also engage learners in noticing and co-construction of knowledge. Pedagogical implications and challenges are addressed and suggestions for future research are advanced. IntroductionThe use of weblogs, more commonly known as blogs, for social communication has been growing in popularity in recent years across the globe. The number of blog users is increasing at an exponential rate each year. Take the case of China. By the end of December 2011, the total number of blog users had climbed to 319 million, an increase of 8.2% for the same time period in 2010 (Tencent IT, 2012). The active users of micro-blogs arrived at 254 million in 2011, an increase of 150.7% over 2010 (NetEase Tech, 2012). Chinese netizens are taking advantage of this novel form of communication to enjoy freedom of speech, to a larger extent, and blogs have become a crucially important avenue for the netizens to express their own views about personal interests, politics, and social issues. The same phenomenal growth of blogging can also be seen elsewhere. For instance, in the United States, an estimated number of blog readers reached 122.6 million in 2011, with a 2.5% increase over the previous year (Reese, 2012). In South Korea, most of the Internet users (89.7%) were social networking service (SNS) users, and more than 70% of these SNS users used blogs in 2011, which accounted for 84.0% of the respondents surveyed (Korea Internet & Security Agency, 2012). Obviously blogging has, at least to some extent, become part of social life for people in the digital era, without the demarcation of physical boundaries, social ideologies, race, and complexion.In the educational sphere blogs have been explored for promoting teaching and learning (Brescia & Miller, 2006;Ellison & Wu, 2008). Kim (2008) found that blogs are advantageous over traditional computer-mediated communication (CMC) applications in terms of their affordances of interactivity, openness, visualization, and decentralization. A vast multitude of other studies (e.g., Churchill, 2009;Glogoff, 2007;Halic, Lee, Paulus & Spence, 2010;Huck, 2007;Kang, Bonk, & Kim, 2011;Yang, 2009;Williams & Jacobs, 2004) have also acknowledged the educational advantages of integrating such a social media tool into the c...