Problem Statement: Nowadays, multiple choice (MC) tests are very common, and replace many constructed response (CR) tests. However, literature reveals that there is no consensus whether both test formats are equally suitable for measuring students' ability or knowledge. This might be due to the fact that neither the type of MC question nor the scoring rule used when comparing test formats are mentioned. Hence, educators do not have any guidelines which test format or scoring rule is appropriate. Purpose of Study: The study focuses on the comparison of CR and MC tests. More precisely, short answer questions are contrasted to equivalent MC questions with multiple responses which are graded with three different scoring rules. Research Methods: An experiment was conducted based on three instruments: A CR and a MC test using a similar stem to assure that the questions are of an equivalent level of difficulty. This procedure enables the comparison of the scores students gained in the two forms of examination. Additionally, a questionnaire was handed out for further insights into students' learning strategy, test preference, motivation, and demographics. In contrast to previous studies the present study applies the many-facet Rasch measurement approach for analyzing data which allows improving the reliability of an assessment and applying small datasets. Findings: Results indicate that CR tests are equal to MC tests with multiple responses if Number Correct (NC) scoring is used. An explanation seems straight forward since the grader of the CR tests did not penalize wrong answers and rewarded partially correct answers. This means that s/he uses the same logic as NC scoring. All other scoring methods such as the All or-Nothing or University-Specific rule neither reward partial knowledge nor penalize guessing. Therefore, these methods are found to be stricter than NC scoring or CR tests and cannot be used interchangeably. Conclusions: CR tests can be replaced by MC tests with multiple responses if NC scoring is used, due to the fact that the multiple response format measures more complex thinking skills than conventional MC questions. Hence, educators can take advantage of low grading costs, consistent grading, no scoring biases, and greater coverage of the syllabus while students benefit from timely feedback. (authors' abstract)

<p>The main objectives of this study were to investigate (i) anovel wetland treatment technology and (ii) selected bed filtermedia for the removal of contaminants from landfill leachate. Areview of the literature concerning experiences of the use ofconstructed wetlands (CW) for the removal of nitrogen fromlandfill leachate, showed that at least three groups oftreatment systems are in practice: sub-surface flow wetlands,hybrid systems (a combination of vertical and horizontal flowwetlands) and, compact constructed wetland (CCW). Most of thesetypeswere generally effective in reducing nitrogen (N,<i>e.g.</i>NH₄-N, dominant N species in leachate) down toeffluent concentrations of about 10 mg L^-1. Unfortunately, very little evidence ofresponsible mechanisms for the removal of N was presented,although some data indicated denitrification. The treatmentperformance of a compact constructed wetland (CCW) applied atthe Tveta Landfill, Södertälje, Sweden, wasevaluated. Chemically purified leachate and untreated leachatewere applied in periods of 7 day submergence and 7 day drainageto different sections of the CCW. The removal efficiency variedbetween 40 and 82%, and a mass removal rate of up to 5.1 g m²d^-1was achieved. The chemical pre-treatment had adecisive role for the highest removal efficiencies obtained andit was unclear whether that treatment enhanced the efficiencybecause of lower toxicity and/or content of fewer competingcations. The possible combination of bed filter media and CCWas an ecotechnological treatment method for landfill leachatewas investigated by bench-scale laboratory column experiments.Reactive filter media (sorbents) was selected from their knownor suggested capacities for removal of heavy metals, nitrogenand phosphorus. Quartz sand or natural sand from an esker wasused as reference medium. Peat was used as an additionalcomponent in mixtures with the reactive media Polonite^®(product from the bedrock opoka) and blastfurnace slag (BFS). A small column study also involved zeolite.Phosphorus was efficiently removed by Polonite^®and NH₄-N to some extent. Concerning metal removal, thebest performance was found as well for Polonite^®, especially for Mn, Fe, Zn and Cu. The BFSshowed good removal efficiency for Cu, Ni and Mo. The removalof different elements was suggested to be a combination ofseveral factors,<i>e.g.</i>precipitation, ion exchange and adsorption. Priorto full-scale application of reactive filters at a landfillsite, matrix selection, filter design and operationalprocedures must be developed.</p><p><b>Keywords:</b>Blast furnace slag; Compact constructedwetland; Metals; Nitrogen; Polonite; Sorbents</p>

This article explores some of the social processes and functions within a community of learners who had to adjust to changing social and academic contexts. The group included 13 learners from Botswana, five of whom were males and eight of whom were females, with an age range of between 25 and 45 years. The learners were primarily Tswana-speaking, with the exception of one who spoke Afrikaans. The learners were registered for an informal one-year counselling certificate course at the North-West University, Potchefstroom Campus. The Botswana learners had no prior contact with mainly white, Afrikaans-speaking communities, such as those found in Potchefstroom. As a result, they had to make various adjustments on personal, academic and social levels. An inductive qualitative approach was followed, using the Mmogo™-method as a case study, to gain insight into the experiences of a group of learners. The Mmogo™-method facilitated the use of culturally appropriate items and the learners were able to use cultural symbols to reflect on their experiences. The learners were asked to make visual presentations of their experiences throughout the time spent in their new contexts. Thereafter focus group discussions were conducted, where the visual presentations were discussed. The central themes were derived from the focus group data and the analysis of the visual presentations. The findings indicate that the process of creating new social meanings occurred through various phases. The initial phases were marked by uncertainty and misconceptions. The early interactions among the community of learners led them to realise that they generally shared the same goals, and also had other things in common, such as political and religious beliefs. The development of a collective consciousness was characterised by the emergence of smaller groups within the large community. As time went by, the collective consciousness in the community deepened and the smaller groups became more diffused. This contributed to open sharing of information and knowledge creation; and it facilitated the attainment of goals. The findings also indicate that there were a number of processes involved in the construction of meanings that contributed to the negotiation of meaning, and an exchange of ideas and information within the community of learners. The communication patterns within the community of learners were found to be open, honest and inclusive. This contributed to the free flow of information and facilitated minimisation of misconceptions. In addition, these patterns facilitated decision-making and encouraged feelings of belonging within the community. Natural leadership emerged and the responsibilities associated with it were discharged in specific and African-conscious ways. The learners also used context-specific analogies to illustrate relational support within their community. For example, they compared relational support to oxen pulling a plough and to a traditional three-legged pot to express the extent to which they mutually depended on each other's talents and resources. The findings also point to certain underlying assumptions that contributed to the development of relational support. In this community, a collective consciousness and sense of trust emerged as the learners worked together towards their goals. The values of sharing and working together are also the defining features of the African worldview. / Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2008.

Constructed reefs are used successfully in marine systems to enhance spawning habitat; this study examines the effectiveness of constructed reefs in a tidal-freshwater river. Fish abundance, species diversity and richness, residency, water column position, reproductive guilds, and feeding guilds were analyzed on two constructed reefs in the tidal-freshwater James River and compared to silted regions representing the primary substrate in the river. Reefs were sampled using hydroacoustics, electroshocking, gillnetting, trawling, and egg mats. The constructed reefs had a greater proportion of fish that broadcast spawn over hard substrate and a trend of more overall individual, residential, and demersal fish. The results suggest that the reefs may be attracting a different fish community than their respective comparison sites, though additional research on the effectiveness of constructed reefs in tidal-freshwater rivers is recommended.

Ces travaux contribuent à caractériser des compartiments environnementaux (i.e. eau, sol et solution du sol, substrat, macrophytes à l’échelle individuelle et des communautés) et leur fonctionnement pour in fine améliorer l’efficacité de zones humides construites (CW) à décontaminer une masse d’eau contaminée en cuivre. Les connaissances sur le maintien de l’homéostasie de Cu chez les végétaux ainsi que sa phytotoxicité aux expositions élevées sont résumées. Les principaux mécanismes physico-chimiques et biologiques intervenant en phytoremédiation d’eaux contaminées en Cu en CW sont également discutés. Plusieurs solutions de phytoremédiation de type phytostabilisation aidée ont été évaluées en lysimètres in situ sur un site de traitement du bois contaminé au Cu, afin d’établir le potentiel de certains amendements à sorber Cu dans le substrat des CW. Les concentrations en éléments traces potentiellement toxiques (PTTE, dont Cu) et macroéléments des lixiviats migrants vers les horizons aquifères ont été quantifiées. Un laitier sidérurgique de type Linz-Donawitz enrichi en P (LDS, 1%) a permis le meilleur développement de Lemna minor L., utilisé ici comme bioindicateur, exposée aux lixiviats. En parallèle, les communautés de macrophytes ont été suivies le long du parcours de la Jalle d’Eysines, une rivière urbaine contaminée en Cu et autres PTTE. Les concentrations en PTTE ont été déterminées dans le sol, l’eau, l’eau interstitielle et les feuilles de 7 espèces de macrophytes. Un modèle statistique multivarié (analyse discriminante linéaire, LDA) a ensuite été élaboré sur la base des concentrations foliaires en PTTE pour biosurveiller l’exposition des macrophytes. Des populations de macrophytes ont aussi été prélevées sur des zones humides de contamination croissante en Cu en Europe (France, Espagne, Portugal et Italie), Biélorussie et Australie. La production de racines chez les macrophytes exposées pendant 3 semaines à des concentrations croissantes en Cu (0,08 ; 2,5 ; 5 ; 15 et 25 µM Cu) montre une variabilité intra-spécifique de la tolérance au Cu pour des populations de Juncus effusus, Schoenoplectus lacustris et Phalaris arundinacea. A l’inverse, une réponse similaire à une tolérance constitutive a été obtenue chez Typha latifolia et Iris pseudacorus, deux espèces à forte production de rhizomes. L’importance des rhizomes est discutée. Phragmites australis produit également des rhizomes, mais a présenté une variabilité intra-spécifique dans sa production racinaire en réponse à une exposition au Cu. En CW, à l’échelle du mésocosme (110 dm3), jusqu’à 99% du Cu de la masse d’eau (concentration initiale: 2.5µM Cu) ont été éliminés dans les trois modalités plantées de Juncus articulatus, P. arundinacea et P. australis, ainsi que dans le contrôle non planté. Les rôles du biofilm microbien, du substrat et des macrophytes en CW ainsi que leurs interactions sont discutés. La sélection d’écotypes de macrophytes tolérants aux PTTE pour leur utilisation en zone humide construite ainsi que les mécanismes moléculaires impliqués dans la variabilité intra-spécifique de cette tolérance, notamment chez P. australis, sont deux thèmes de recherche à promouvoir. / This work aims at characterizing environmental compartments (i.e. water, soil and soil pore water, substrate, macrophytes at the individual and community scale) and their functioning to in fine improve the effectiveness of constructed wetlands (CW) for cleaning Cu-contaminated waters. Knowledge on the homeostasis of Cu in plants and its phytotoxicity at medium and high exposures are summarized. The main physico-chemical and biological mechanisms involved in the phytoremediation of Cu-contaminated water in CW are discussed. Several aided-phytostabilisation options were in situ evaluated in lysimeters at a Cu-contaminated wood preservation site to assess the potential of four amendments to sorb Cu in a CW substrate. Concentrations of potentially toxic trace elements (PTTE, including Cu) and macronutrients of leachates migrating from the root zone to the aquifers were quantified. Based on the responses of Lemna minor L. used as a bioindicator, exposed to the leachates,.Linz-Donawitz slag spiked with P (LDS, 1%) best performed to sorb labile Cu in the root zone. In parallel, macrophyte communities were monitored along the Jalle Eysines River, an urban river slightly contaminated by Cu and other PTTE. The PTTE concentrations were determined in the soil, water, soil pore water, and in the leaves of seven macrophyte species. A multivariate statistical model was developed based on the foliar PTTE concentrations for biomonitoring macrophyte exposures. Populations of macrophytes were also collected in wetlands displaying an increasing Cu contamination in Europe (France, Spain, Portugal, and Italy), Belarus and Australia. Root production of macrophytes exposed for 3 weeks at increasing Cu concentrations (0.08, 2.5, 5, 15 and 25 µM Cu) shows an intra-specific variability of Cu tolerance in populations of Juncus effusus, Schoenoplectus lacustris and Phalaris arundinacea. In contrast, a similar response to constitutive tolerance occurred for Typha latifolia and Iris pseudacorus, two species with high production of rhizomes. The rhizome influence is discussed. Phragmites australis also produces rhizomes but showed intra-specific variability in response to Cu exposure. In a CW at mesocosm scale (110 dm3), up to 99% of Cu in water (initial concentration: 2.5μM Cu) was removed after 2 weeks in the three modalities planted with Juncus articulatus, P. arundinacea and P. australis, and in the unplanted control. The influences of microbial biofilms, the substrate, and the macrophyte species and their interactions in CW are discussed. The selection of PTTE-tolerant macrophytes for their used in CW and the understanding of molecular mechanisms underlying the intra-specific variability in PTTE- tolerance, i.e for P. australis, require further investigations.

Este trabalho contém uma revisão bibliográfica relativa à eficiência de wetlands construídas para a remoção de nitrogênio total e fósforo total. Também foram revisados diversos modelos matemáticos para a simulação desta remoção e foi efetuada uma análise crítica destes modelos. Foram empregados dados de domínio público da eficiência de remoção de nutrientes por wetlands construídas de fluxo superficial. Estes dados foram analisados procurando-se calibrar um modelo matemático para a simulação da eficiência de remoção. Observou-se, porém, que estes dados apresentam comportamento bastante complexo, sendo que, por vezes, a eficiência de remoção medida apresenta valores negativos. Partiu-se então para uma abordagem estatística destes dados, a qual poderá servir para a avaliação do risco de ocorrência de desempenho insatisfatório envolvido no dimensionamento de wetlands construídas. / This work presents a bibliographic review about the efficiency of constructed wetlands to remove total nitrogen and total phosphorus. Also many mathematics models to simulate this removal were reviewed and a critical analysis of these models was carried out. Public domain data about the removal efficiency of nutrients by constructed wetlands of surface flux were used. These data were analyzed in order to fit a mathematical model to simulate the removal efficiency. However it was found that these data present a complex behavior, including the occurrence of negative values. A statistical approach of these data was then carried out as an attempt to assess the risk of unsatisfactory performance involved in the design of constructed wetlands.

Este trabalho contém uma revisão bibliográfica relativa à eficiência de wetlands construídas para a remoção de nitrogênio total e fósforo total. Também foram revisados diversos modelos matemáticos para a simulação desta remoção e foi efetuada uma análise crítica destes modelos. Foram empregados dados de domínio público da eficiência de remoção de nutrientes por wetlands construídas de fluxo superficial. Estes dados foram analisados procurando-se calibrar um modelo matemático para a simulação da eficiência de remoção. Observou-se, porém, que estes dados apresentam comportamento bastante complexo, sendo que, por vezes, a eficiência de remoção medida apresenta valores negativos. Partiu-se então para uma abordagem estatística destes dados, a qual poderá servir para a avaliação do risco de ocorrência de desempenho insatisfatório envolvido no dimensionamento de wetlands construídas. / This work presents a bibliographic review about the efficiency of constructed wetlands to remove total nitrogen and total phosphorus. Also many mathematics models to simulate this removal were reviewed and a critical analysis of these models was carried out. Public domain data about the removal efficiency of nutrients by constructed wetlands of surface flux were used. These data were analyzed in order to fit a mathematical model to simulate the removal efficiency. However it was found that these data present a complex behavior, including the occurrence of negative values. A statistical approach of these data was then carried out as an attempt to assess the risk of unsatisfactory performance involved in the design of constructed wetlands.

The boundary between the personal and the professional self is a site of professional and personal creativity and tension, a space that reflects some of the key ontological and epistemological issues confronting social work. Exploring the social construction of the self through the stories of fifteen Australian social workers brings these issues into stark relief. The participatory and reflexive research process facilitated the development of knowledge about how a group of culturally diverse social workers construct personal and professional boundaries in practice.The need to explore these processes and relationships was predicated on a concern that while the self is generally recognised as shaping practice, there has been a paucity of attention given to what lived experiences constitute the self. Social work practice is broadly defined as a socially constructed profession, yet the personal and professional boundary is regarded as individually constructed and defined. This discourse neglects the influence of contextual, cultural, relational and structural dimensions of the self, thus denying the possibilities of practice being continually informed by a myriad of experiences.Recognising that the socially constructed self is situated within intersections of knowledge and meaning opens up possibilities for the development of dialogical practices within an ethics of care. The research also has implications for social work practice and education and for the way that we supervise and manage social work staff. Professional dialogue, debate and practice needs to reflect a diversity of experiences and recognise that the dominant discourse about boundaries and the self leaves many workers feeling that their practice reality is not a shared one.

The aim of this project was to identify a suitable solution to the problem of landfill leachate at the North Katoomba landfill site. Options were affected by a range of constraints including economics, location and the intrusion of ground water into the landfill. The initial goal was to contain and treat the leachate on site, with the eventual target to discharge into the nearest receiving waters. A constructed wetland option was devised and researched, involving identification of the major pollutants contained within the leachate, developing a concept design and estimating the likely removal efficiencies expected. Investigations identified the primary pollution parameters as microbial and nutrients. Metals were found to be low in concentration although the wetland has the capacity to deal with these pollutants should they become part of the pollution plume. A bench scale constructed wetland system was developed to give an indication of the removal efficiencies. The results suggest that a constructed wetland system would be appropriate for treating landfill leachate at the North Katoomba site. It is recommended that a constructed wetland be established in the field to determine the long term treatment prospects and the potential management problems in a practical application. / Master of Science (Hons)

Bibliography : leaves [34]-[40]