Biofilm formation and dispersal in the black rot pathogen Xanthomonas campestris pathovar campestris (Xcc) is influenced by a number of factors. The extracellular mannanase ManA has been implicated in biofilm dispersal whereas biofilm formation requires a putative glycosyl transferase encoded by the xag gene cluster. Previously we demonstrated that the post-transcriptional regulator RsmA exerts a negative regulatory influence on biofilm formation in Xcc. Here we address the mechanisms by which RsmA exerts this action. We show that RsmA binds to the transcripts of three genes encoding GGDEF domain diguanylate cyclases to influence their expression. Accordingly, mutation of rsmA leads to an increase in cellular levels of cyclic di-GMP. This effect is associated with a down-regulation of transcription of manA, but an upregulation of xag gene transcription. Mutation of clp, which encodes a cyclic di-GMP-responsive transcriptional regulator of the CRP-FNR family, has similar divergent effects on the expression of manA and xag. Nevertheless Clp binding to manA and xag promoters is inhibited by cyclic di-GMP. The data support the contention that, in common with other CRP-FNR family members, Clp can act as both an activator and repressor of transcription of different genes to influence biofilm formation as a response to cyclic di-GMP.

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We sought to quantify the effectiveness of a gifted and talented (GT) program, as was provided to university students who demonstrated a talent for learning English as a foreign language (EFL) in China. To do so, we used propensity score matching (PSM) techniques to analyze data collected from a tier-1 university where an English talent (ET) program was provided. Specifically, we provided (a) a step-by-step guide of PSM analysis using the R analytical package, (b) the codes for PSM analysis and visualization, and (c) the final analysis of baseline equivalence and treatment effect based on the matching sample. Collectively, the results of descriptive statistics, visualization, and baseline equivalence indicate that PSM is an effective matching technique for generating an unbiased counterfactual analysis. Moreover, the ET program yields a statistically significant, positive effect on ET students' English language proficiency. the English as a foreign language (EFL) context in China, especially regarding the issues related to methodology and evaluation. Furthermore, we present a practical yet rigorous evaluation method, propensity score matching (PSM), with steps and a demonstration to evaluate the effectiveness of a GT program for EFL, or an English talent (ET) program in the Chinese EFL education context. Literature Review Gifted and Talented and English as a Foreign Language Education in ChinaThere are some unique social and cultural factors in the Chinese educational context that are reflected in GT education. First, Chinese culture places an extremely high value on education [9]. Students have no option but to perform well on the Zhongkao (entrance examination for high school) and in the National College Entrance Examination (NCEE) to be accepted into a well-known high school or top university [10]. It is worth noting that EFL is a required subject for both the Zhongkao and the NCEE, and carries the same weight in the scoring as other core courses, such as Chinese language arts and mathematics. Second, Chinese people have been greatly influenced by the ideology of collectivism, in which individuals should follow the expectation of his/her family and community [11], which leads to the phenomenon that a student's academic achievement represents the glory (mianzi or "face" in Chinese culture) of his/her family [12]. Therefore, in Chinese culture, talented students are always associated with high social status, reputation, and prestige; their family has an even higher expectation of their academic success [9,13]. Third, Chinese general beliefs hold that GT is related to creativity in science, but barely so in liberal arts, which was reported in a few empirical [11,14]. For example, Zhang [13] emphasized that Chinese culture attributes "meritorious salience" to the value of high achievement, while western culture places more value on "aesthetic salience", which results in GT-related research in China focusing on science-related disciplines instead of art or art-related subjects.As was mentioned earlier, EFL is a req...

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