iv Although providing feedback is commonly practiced in education, there is general agreement regarding what type of feedback is most helpful and why it is helpful. This study examined the relationship between various types of feedback, potential internal mediators, and the likelihood of implementing feedback. Five main predictions were developed from the feedback literature in writing, specifically regarding feedback features (summarization, identifying problems, providing solutions, localization, explanations, scope, praise, and mitigating language) as they relate to potential causal mediators of problem or solution understand and problem or solution agreement, leading to the final outcome of feedback implementation.To empirically test the proposed feedback model, 1073 feedback segments from writing assessed by peers was analyzed. Feedback was collected using SWoRD, an online peer review system. Each segment was coded for each of the feedback features, implementation, agreement, and understanding. The correlations between the feedback features, levels of mediating variables, and implementation rates revealed several significant relationships. Understanding was the only significant mediator of implementation. Several feedback features were associated with understanding: including solutions, a summary of the performance, and the location of the problem were associated with increased understanding; and explanations to problems were associated with decreased understanding. Implications of these results are discussed. THE NATURE OF FEEDBACK: HOW DIFFERENT TYPES OF FEEDBACK AFFECT WRITING PERFORMANCEMelissa INTRODUCTIONAlthough giving feedback is a generally accepted practice in educational settings, specific features of effective feedback, such as the complexity (i.e., more versus less information) and timing (i.e., immediate versus delayed) of feedback, have been largely disputed (see Mory, 2003; 1996 for review). Moreover, for a complex task such as writing, the conditions that influence feedback effectiveness are likely to be correspondingly complex. An understanding of the conditions under which writers implement feedback they receive is critical to promoting improved writing. The goal of the present study is to identify some of these conditions, based on the hypothesis that specific mediating causal pathways allow external features to influence the writer's implementation of feedback. We are particularly interested in the case of peer feedback.Peers are increasingly used as a source of feedback, both in professional and instructional settings (Toegel & Conger, 2003;Haswell, 2005). Advice regarding useful peer feedback is particularly lacking.Beyond the specific focus of feedback in writing, there is a long, more general history of research on feedback. Overall, three broad meanings of feedback have been examined (Kulhavy & Wager, 1993): 1) some feedback, such as praise, could be considered a motivator that increases a general behavior (e.g., writing or revision activities overall); 2) feedback may specifi...

The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.

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Genome-wide association analyses are a powerful approach for identifying gene function. These analyses are becoming commonplace in studies of humans, domesticated animals, and crop plants but have rarely been conducted in bacteria. We applied association analyses to 20 traits measured in Ensifer meliloti, an agriculturally and ecologically important bacterium because it fixes nitrogen when in symbiosis with leguminous plants. We identified candidate alleles and gene presence-absence variants underlying variation in symbiosis traits, antibiotic resistance, and use of various carbon sources; some of these candidates are in genes previously known to affect these traits whereas others were in genes that have not been well characterized. Our results point to the potential power of association analyses in bacteria, but also to the need to carefully evaluate the potential for false associations.