Data-driven estimates of global nitrous oxide emissions from croplands

Croplands are the single largest anthropogenic source of nitrous oxide (N₂O) globally, yet their estimates remain difficult to verify when using Tier 1 and 3 methods of the Intergovernmental Panel on Climate Change (IPCC). Here, we re-evaluate global cropland-N₂O emissions in 1961–2014, using N-rate-dependent emission factors (EFs) upscaled from 1206 field observations in 180 global distributed sites and high-resolution N inputs disaggregated from sub-national surveys covering 15593 administrative units. Our results confirm IPCC Tier 1 default EFs for upland crops in 1990–2014, but give a ∼15% lower EF in 1961–1989 and a ∼67% larger EF for paddy rice over the full period. Associated emissions (0.82 ± 0.34 Tg N yr^–1) are probably one-quarter lower than IPCC Tier 1 global inventories but close to Tier 3 estimates. The use of survey-based gridded N-input data contributes 58% of this emission reduction, the rest being explained by the use of observation-based non-linear EFs. We conclude that upscaling N₂O emissions from site-level observations to global croplands provides a new benchmark for constraining IPCC Tier 1 and 3 methods. The detailed spatial distribution of emission data is expected to inform advancement towards more realistic and effective mitigation pathways.     

Prediction of the P-leaching potential of arable soils in areas with high livestock densities

Due to long-term positive P-balances many surface soils in areas with high livestock density in Germany are oversupplied with available P, creating a potential for vertical P losses by leaching. In extensive studies to characterize the endangering of ground water to P pollution by chemical soil parameters it is shown that the available P content and the P concentration of the soil solution in the deeper soil layers, as indicators of the P-leaching potential, cannot be satisfactorily predicted from the available P content of the topsoils. The P equilibrium concentration in the soil solution directly above ground water table or the pipe drainage system highly depends on the relative saturation of the P-sorption capacity in this layer. A saturation index of 〈20% normally corresponds with P equilibrium concentrations of〈0.2 mg P/L. Phytoremediation may reduce the P leaching potential of P-enriched soils only over a very long period.     

Auswahlbibliografie

Auswahlbibliografie

Auswahlbibliografie     

The quasi-experimental attitude of teachers: the development of a questionnaire

This article reports on the development and testing of a questionnaire that can be used to measure the quasi-experimental attitude (QEA) of teachers. This attitude is reflected in the willingness of teachers to assess and organise their core activities (planning, implementing and analysing lessons) by analogy with experiments in the field of research, in order to gain meaningful experiences from this cyclical process, to evaluate critically these experiences and to draw from them conclusions on how to improve lessons in the future. The sample comprised 512 trainee teachers who had already been teaching independently for 15 months following the conclusion of their university studies. The analysis of the questionnaire showed that the reliability of the scale was satisfactory. Confirmatory factor analyses confirmed the assumption that the quasi-experimental attitude could be modelled in two ways: A first-order model with four intercorrelated factors (meticulous lesson planning, confidence in the predictability of how the lesson will turn out, evidence-based analysis of the lesson and scepticism about mere experience) and a second-order model in which these four factors are loading on the overarching factor QEA. Additionally, the instrument yielded plausible correlations to several validity criteria.     

Preparing pre-service teachers to integrate technology into K–12 instruction: evaluation of a technology-infused approach

The quality of how technology is addressed in teacher education programmes is conditional for how student teachers apply technology in secondary schools after their graduation. Two technology-infused courses of one teacher education programme were evaluated. In line with studies on the development of pre-service teachers’ technological, pedagogical and content knowledge, two important enablers were distinguished: (1) teaching practice to enact what was learned in teacher education institution as well as to receive feedback from students on this enactment, and (2) modelling of teacher educators and teachers in school. Both enablers might require further development of knowledge and skills of both teacher educators and cooperating school teachers.     

Video narratives to assess student teachers’ competence as new teachers

In teacher education programmes, written portfolios or text-based self-evaluations are generally used to document the development of student teachers’ competence. However, such approaches do no justice to the complex nature of teaching as they tend to lead to evidence in which teacher competencies are disconnected and removed from the actual teaching practice. In one postgraduate teacher education programme, video narratives were evaluated as a valid way to assess student teachers’ teaching competencies, promoting connections amongst different competencies, situating these in practice and showing their development over time. Data were gathered from self-reports of both teacher educators and student teachers as well as student teachers’ completed video narratives. Most student teachers succeeded in meeting the set criteria for the video narrative assignment with connected video clips and text frames. However, student teachers also came up with only a few video episodes and loosely connected clips, reflections and other sources. Although most of the students during the programme did explicitly reflect upon their personal development towards becoming a teacher, almost none of them explicitly connected these ideas to their long-term development. We conclude that video narratives show potential to be used as a valid assessment of student teachers’ teaching competence. Yet, structured guidance as well as ill-structured assignments are needed in framing assessment of student teachers in teacher preparation: the former to clarify the aims, format and criteria and the latter to enable student teachers to reflect on their teaching in a personally, meaningful way.     

Gestaltungsmerkmale und Effekte ganztägiger Angebote im Grundschulbereich

Zusammenfassung Ganzt?gige schulische Angebote spielen in der aktuellen Debatte um eine Bildungsreform eine zentrale Rolle. Erwartungen an ihre erzieherischen und leistungsbezogenen Wirkungen werden hier zun?chst theoretisch auf dem Hintergrund der Schuleffektivit?tsforschung diskutiert. Empirisch werden — erstmals repr?sentativ für Deutschland — p?dagogische Angebote und Schülerleistungen an Grundschulen mit und ohne Ganztagsangebot verglichen. Basis ist eine Sekund?ranalyse von Daten der internationalen Grundschul-Leseuntersuchung IGLU in Verbindung mit einer nachtr?glichen Schulleiterbefragung. Schulen mit ganzt?gigen Angeboten verfügten demnach über ein breites Spektrum von p?dagogischen Ma?nahmen, wobei in Ganztagsschulen mit systematischem Konzept die kognitive F?rderung relativ stark gewichtet war. Effekte auf das Niveau des Leseverst?ndnisses oder dessen Zusammenhang mit der sozialen Herkunft fanden sich nicht.      

Reconsidering group cognition: From conceptual confusion to a boundary area between cognitive and socio-cultural perspectives?

Various strands of research in educational, social and organizational psychology focus on structures of collectively created meaning that emerge in and coordinate activities of groups. Despite expanding, this field still lacks conceptual clarity, enhanced by the multitude of terms used, such as common ground, shared understanding, collective mind, team mental models, and distributed cognition.We conducted a review of the conceptual frameworks being used in empirical studies, focusing on the premises of the conceptualizations. Therefore, we connected these conceptualizations to either cognitive or socio-cultural perspectives on the social nature of cognition. Some studies are identified as representing initial ways of boundary crossing between these perspectives. To conclude, we explore ways for boundary crossing and cross-fertilization in future research.     

Effects of self-questioning on EFL students’ engagement in literary reading / Los efectos del autocuestionamiento en la lectura comprometida de textos literarios de estudiantes de inglés como lengua extranjera

This study examines the effects of self-questioning on EFL students’ literary reading engagement. Two interventions were tested: (1) students generating questions while reading short stories, and then exploring their questions in small-groups; and (2) students generating questions while reading, and then reflecting through a free writing activity. Participants were 59 Vietnamese undergraduate students enrolled in an English as a foreign language course. A pre-test post-test control group design with switching replications was used, with a control condition in which the teacher (instead of the students) posed the questions. Students’ reading engagement was measured by a written response to a short story and a questionnaire. Results showed that both self-questioning interventions positively influenced students’ reading engagement compared to the control condition. A maintenance of effects was also observed. We conclude that self-questioning combined with group discussions or free writing promotes students’ reading engagement.