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Designing and evaluating teacher development programs for graduate teaching assistants (GTAs) who teach in the laboratory is a prominent feature of chemistry education research. However, few studies have investigated the impact of a GTA teacher development program on the verbal interactions between participating GTAs and students in the undergraduate laboratory. Further, little research has been devoted to the development of an instructional model designed specifically for GTAs. This research set out to develop an instructional model to underpin a GTA teacher development program and to evaluate its impact on the cognitive and psychomotor verbal interactions between GTAs and students in the laboratory. Seven GTAs participated in the "Teaching as a Chemistry Laboratory Graduate Teaching Assistant" (TCL-GTA) program that featured the development and implementation of the "Meaningful Learning in the Laboratory" (MLL) instructional model seeking to nurture undergraduate students' cognitive, psychomotor, and affective domains of learning. The verbal interactions between each GTA and the students they interacted with were audio recorded for the entire duration of general chemistry laboratory sessions that took place before, during, and after the TCL-GTA program. The purpose of this article is to explore the influence of the TCL-GTA program on the cognitive and psychomotor verbal interactions between GTAs and undergraduate students during general chemistry laboratory sessions.

Background: Struvite, biochar and ash products (collectively known as STRUBIAS) derived from different waste streams are used as fertilisers in agriculture. Raw dairy processing sludge (DPS) shows promise as bio‐based fertilisers, but secondary STRUBIAS‐derived products need further testing as fertilisers. Aims: The objective of this study was to calculate the phosphorus mineral fertiliser equivalency (P‐MFE) for some STRUBIAS products derived from DPS. Methods: Ryegrass (Lolium perenne L.) and wheat (Triticum aestivum) pot trials were used to determine the P‐MFE using the apparent P recovery (APR) method for Fe‐DPS and DPS‐derived struvites (Struvite 1–4), hydrochars (HC1–3) and ash. Results: The tested STRUBIAS products can be divided into two groups: (1) a range of products that can (i.e. Struvite 1–3) and (2) cannot (i.e., Struvite 4, HC1–3, ash and Fe‐DPS) be considered fertilisers. In the first group, the P‐MFE ranged from 66.8% to 76.7% for ryegrass and from 77.9% to 93.5% for spring wheat grain. In the second group, the P‐MFE ranged from 7.8% to 58.3% for ryegrass and from −34.5% to −151.3% for spring wheat grain. The negative agronomic effects of some products for wheat grain (struvite and HC) in this study were mainly caused by high Fe content, which could be overcome by improved treatment processes. Conclusions: Future policy and research must be aware that not all the DPS‐derived STRUBIAS products are suitable as fertilisers and therefore need to be tested individually. [ABSTRACT FROM AUTHOR]

Graduate students who fulfill teaching roles in the undergraduate laboratory play an important role in establishing a positive learning environment. A host of various graduate teacher training programmes have been developed, implemented and evaluated accordingly in order to enhance their teaching capability. In addition research has also documented the varied or sometimes complex factors that influence graduate students' teaching capability. This present study set out to explore graduate students' sense of psychological empowerment as an influencing factor on their perceived teaching self-image and behaviours. The Teaching as a Chemistry Laboratory Graduate Teaching Assistant (TCL-GTA) programme was developed to enhance the sense of psychological empowerment experienced by seven chemistry graduate students at an Irish University as a means of enhancing their perceived teaching self-image and behaviours. The data collected throughout this study involved both qualitative and quantitative forms through conducting interviews and administering questionnaires. The findings of this research suggest that the level of psychological empowerment experienced by graduate students lends considerable and positive contributions to their perceived teaching self-image and behaviours which are influenced by a number of contextual, training and personal factors. This research should interest those involved in teaching chemistry in higher education as well as those interested in empowerment of either teachers or postgraduate students undertaking teaching duties.

Throughout countries such as Ireland, the U.K., and Australia, graduate students who fulfill teaching roles in the undergraduate laboratory are often referred to as "laboratory demonstrators". The laboratory demonstrator (LD) model of graduate teaching is similar to the more commonly known graduate teaching assistant (GTA) model that is prevalent in the United States. While the responsibilities of LDs and GTAs in the undergraduate laboratory are similar, both cohorts experience different recruitment and training processes that can influence their teaching behaviors. With respect to enhancing the teaching capability of GTAs, considerable research has investigated the design, implementation, and evaluation of various GTA teacher development programs as well as identified various factors that influence their teaching behaviors. However, there has been relatively less research devoted to enhancing the teaching capability of LDs. This research study set out to inform the design of a teacher development program for graduate students who fulfill LD roles. This study involved the collection of both quantitative and qualitative data as a means of comparing LDs (N = 28) and undergraduate students' (N = 224) perceptions of LDs' responsibilities in addressing cognitive, affective, and psychomotor learning experiences in the noninquiry general chemistry laboratory. In catering to the misalignment of perceived LD responsibilities, this research offers faculty the evidence-align-develop framework that can inform the design of a teacher development program for LDs. Given the similarities between LDs and GTAs with respect to their status as graduate students, their relative experience in learning chemistry, as well as their role in the laboratory, this framework can also inform the design of GTA teacher development programs.

Animal slurry is separated in order to avoid excessive nitrogen, phosphorus and potassium (NPK) fertilization of crops in the field. To enhance fertilizer efficiency further, slurry and its separation products may be acidified, for instance in animal houses. The current study quantified the effects of these treatments, both individually and in combination, on fertilizer efficiency, energy production and heavy metal accumulation as a result of manure management. Acidification increased the availability of N to plants in the manure applied, and provided a better match between plant-available NPK in the manure and separation fraction applied to fields and crop need. Total biogas production was not affected by separation, whereas acidification reduced biogas production because the process was inhibited by a low pH and a high sulphur concentration. The amount of copper applied per hectare in the liquid manure to the wheat field was lower than the amount taken up and more zink and copper was applied in the solid fraction to maize field than taken up. The transportation and field application of solids and liquids did not increase management costs when compared to the transportation of slurry alone, but the investment and running costs of separators and manure acidification increased overall management costs. [ABSTRACT FROM PUBLISHER]