The Framing Discussion: Connecting Student Experience with Mathematical Knowledge

This article introduces the framing discussion, an informal discussion of a mathematical problem that takes place at the beginning of a lesson or unit. The purpose of the framing discussion is to assess student knowledge, motivate student interest, and to serve as a basis for guiding students to more formal mathematical knowledge. The article discusses the design criteria and the discourse moves necessary to execute an effective framing discussion.     

CO2-Einsparpotenziale des Energietr?gers Erdgas

Zusammenfassung Angesichts der staatlichen Klimaschutzziele stellt sich die Frage, wie diese mit m?glichst geringer Beeintr?chtigung einer sicheren Versorgung zu günstigen Preisen erreichbar sind. Erdgas, das im Vergleich zu anderen fossilen Energietr?gern deutlich kohlenstoff?rmer ist und darüber hinaus bei der Verbrennung auch keine weiteren Schadstoffe emittiert, kann hier einen Beitrag leisten. Gegenw?rtig hat Erdgas für die Versorgung mit W?rme sowie bei der Erzeugung von Strom eine erhebliche Bedeutung, die zukünftig weiter wachsen wird. Anhand verschiedener Szenarien werden Prognosen zur weiteren Entwicklung von Erdgas und die Auswirkungen auf die CO₂-Emissionen angestellt. Es zeigt sich, dass der Anteil von Erdgas im Bereich der W?rmeversorgung von 46 % auf 56 % steigen wird. Durch ?nderung des Energiemix und Effizienzsteigerungen kann der CO₂-Aussto? für Raumw?rme daher bis 2020 um 8,3 % gesenkt werden. Für die Stromerzeugung werden alternative Szenarien berechnet. Beim derzeitigen Energiemix k?me es zu einer j?hrlichen Steigerung des CO₂-Aussto?es um 0,8 %. Würde Kohle komplett durch Gas ersetzt, k?nnte der CO₂-Aussto? j?hrlich um 1,9 % gesenkt werden.

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Given the governmental climate targets, the question arises how these targets can be achieved without affecting a secure and cheap energy supply. As natural gas causes less carbon emissions than any other fossil fuel it might be able to make a contribution in this regard. Currently, in the generation of heat and power natural gas plays a significant role, which will further increase in the future. Using several scenarios, we predict the development of the importance of natural gas and the consequences for carbon emissions. The calculations show that the share of natural gas for the supply of heat will increase from 46 % to 56 %. Efficiency increases together with changes in the structure of power generation can reduce heating-related carbon emissions by 8.3 % until 2020. For power generation, we calculate alternative scenarios. If the current structure of power generation is held constant, carbon emissions will increase by 0.8 % p.a. If instead natural gas completely replaces coal and lignite, the carbon emissions will be reduced by 1.9 % per year.

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Dieser Beitrag ist eine Kurzfassung der Studie „Wirtschaftsfaktor Erdgasbranche“, HWWI Policy Paper 1–3, Hamburg     

Infant and maternal sensitivity to interpersonal timing

A perturbation paradigm was employed to assess 3- and 6-month-old infants' and their mothers' sensitivity to a 3-s temporal delay implemented in an ongoing televised interaction. At both ages, the temporal delay affected infant but not maternal behavior and only when implementing the temporal delay in maternal (Experiment 1, N=64) but not infant (Experiment 2, N=60) behavior. In addition, the experimental manipulation influenced promptness of maternal smiling responses reliably more than promptness of infant smiling responses. The findings suggest that the timing of maternal behavior plays an important role in infants' perception of maternal responsiveness, whereas mothers seem to monitor general aspects of infant behavior such as overall level of engagement.     

Recruiting the graduate voice: informing higher education initiatives to underpin an emerging,veterinary paraprofession in Australia

In Australia, the inception of veterinary technology, as a higher education discipline underpinning an emerging, mid-tier paraveterinary field, reflected global trends for more highly educated veterinary paraprofessionals to meet changing societal demands. In this study, veterinary technology graduates were surveyed about their experiences in the workforce and reflections on their education. Seeking feedback on how well a new programme has prepared graduates for the workforce is a useful quality assurance tool. Clinical veterinary practice was the primary employment sector with the majority of respondents in full-time employment. Career advancement, professional recognition and salaries were identified as key career challenges. The important roles of the veterinary and veterinary nursing professions, the university, government and graduates in the development of this mid-tier, veterinary paraprofession were elucidated. Graduates’ feedback on criteria that underpinned ‘work-readiness’ revealed seven key domains: communication skills, research skills, knowledge, critical thinking/problem-solving, employability, practical skills and professionalism. Veterinary nursing skills, work placement, practice management and production animal health were flagged as areas for curricular improvement. This study illuminated facilitators and barriers critical to establishing a mid-tier veterinary paraprofession, bridging the divide between the vocational and higher education sectors in Australia.

Abbreviations: AUD: Australian dollar; AVA: Australian Veterinary Association; AVBC: Australasian Veterinary Boards Council; AVMA: American Veterinary Medical Association; BVNA: British Veterinary Nursing Association; CSU: Charles Sturt University; DAF: Department of Agriculture and Fisheries; FWC: Fair Work Commission; GCA: Graduate Careers Australia; HE: Higher Education; NHMRC: National Health and Medical Research Council; QLD: Queensland; RCVS: Royal College of Veterinary Surgeons; UK: United Kingdom; UQ: University of Queensland; VN: Veterinary nursing; VNCA: Veterinary Nurses Council of Australia; VSB: Veterinary Surgeons Board; VT: Veterinary technology; WIL: Work-integrated learning.     

Evaluating multimodal relevance feedback techniques for medical image retrieval

Medical image retrieval can assist physicians in finding information supporting their diagnosis and fulfilling information needs. Systems that allow searching for medical images need to provide tools for quick and easy navigation and query refinement as the time available for information search is often short. Relevance feedback is a powerful tool in information retrieval. This study evaluates relevance feedback techniques with regard to the content they use. A novel relevance feedback technique that uses both text and visual information of the results is proposed. The two information modalities from the image examples are fused either at the feature level using the Rocchio algorithm or at the query list fusion step using a common late fusion rule. Results using the ImageCLEF 2012 benchmark database for medical image retrieval show the potential of relevance feedback techniques in medical image retrieval. The mean average precision (mAP) is used as the evaluation metric and the proposed method outperforms commonly-used methods. The baseline without feedback reached 16 % whereas the relevance feedback with 20 images reached up to 26.35 % with three steps and when using 100 images up to 34.87 % in four steps. Most improvements occur in the first two steps of relevance feedback and then results start to become relatively flat. This might also be due to only using positive feedback as negative feeback often also improves results after more steps. The effect of relevance feedback in automatically spelling corrected and translated queries is investigated as well. Results without mistakes were better than spell-corrected results but the spelling correction more than double results over non-corrected retrieval. Multimodal relevance feedback has shown to be able to help visual medical information retrieval. Next steps include integrating semantics into relevance feedback techniques to benefit from the structured knowledge of ontologies and experimenting on the fusion of text and visual information.     

Teachers’ perceptions of their most significant change: source,impact, and process

The purpose of the study was to examine the differences among significant changes in the practice of individual teachers. Seventeen US teachers were interviewed about the most successful change in their teaching career. The differences in teacher change were based primarily on the source and impact of the change. The sources of change were divided into two categories: other-initiated or self-initiated. The level of impact was determined in three ways: by whether teachers described a new practice, a new direction, or a change in their beliefs. By organizing according to both the source and impact of the change, four types of change were identified: Response to School Initiatives, Professional Development Initiatives, Student-Centered Changes, and Self-Designed Changes. Self-Designed changes were further distinguished based on the time required for the change process. Implications for developing new strategies to foster teacher development are discussed.     

Renal lactate elimination is maintained during moderate exercise in humans

Reduced hepatic lactate elimination initiates blood lactate accumulation during incremental exercise. In this study, we wished to determine whether renal lactate elimination contributes to the initiation of blood lactate accumulation. The renal arterial-to-venous (a-v) lactate difference was determined in nine men during sodium lactate infusion to enhance the evaluation (0.5 mol x L(-1) at 16 ± 1 mL x min(-1); mean ± s) both at rest and during cycling exercise (heart rate 139 ± 5 beats x min(-1)). The renal release of erythropoietin was used to detect kidney tissue ischaemia. At rest, the a-v O(2) (CaO(2)-CvO(2)) and lactate concentration differences were 0.8 ± 0.2 and 0.02 ± 0.02 mmol x L(-1), respectively. During exercise, arterial lactate and CaO(2)-CvO(2) increased to 7.1 ± 1.1 and 2.6 ± 0.8 mmol x L(-1), respectively (P < 0.05), indicating a -70% reduction of renal blood flow with no significant change in the renal venous erythropoietin concentration (0.8 ± 1.4 U x L(-1)). The a-v lactate concentration difference increased to 0.5 ± 0.8 mmol x L(-1), indicating similar lactate elimination as at rest. In conclusion, a -70% reduction in renal blood flow does not provoke critical renal ischaemia, and renal lactate elimination is maintained. Thus, kidney lactate elimination is unlikely to contribute to the initial blood lactate accumulation during progressive exercise.