Definition of historical models of gene function and their relation to students’ understanding of genetics     

Niklas Markus Gericke  Mariana Hagberg 《Science & Education》2007,16(7-8):849-881

Models are often used when teaching science. In this paper historical models and students’ ideas about genetics are compared. The historical development of the scientific idea of the gene and its function is described and categorized into five historical models of gene function. Differences and similarities between these historical models are made explicit. Internal and external consistency problems between the models are identified and discussed. From the consistency analysis seven epistemological features are identified. The features vary in such ways between the historical models that it is claimed that learning difficulties might be the consequence if these features are not explicitly addressed when teaching genetics. Students’ understanding of genetics, as described in science education literature, is then examined. The comparison shows extensive parallelism between students’ alternative understanding of genetics and the epistemological features, i.e., the claim is strengthened. It is also argued that, when teaching gene function, the outlined historical models could be useful in a combined nature of science and history of science approach. Our findings also raise the question what to teach in relation to preferred learning outcomes in genetics.  相似文献   

Robin Hood or Matthew? Children’s Reasoning About Redistributive Justice in the Context of Economic Inequalities     

Samuel Essler  Markus Paulus 《Child development》2021,92(4):1254-1273

How should one respond to ubiquitous economic inequalities? The legend Robin Hood suggests to take away from the wealthy to benefit the poor, whereas another strategy holds the opposite (Matthew effect). Here, 3- to 8-year-old children (N = 140) witnessed protagonists performing redistributions (e.g., Robin Hood, Matthew) of necessary and luxury resources between a wealthy and a poor child. Results showed that, with age, children increasingly approved of Robin Hood and increasingly disapproved of Matthew. In addition, reasoning about others’ welfare mediated the effect of age on children’s evaluation of Robin Hood, but only for necessary resources. This suggests that children regard restorative justice actions as a strategy to address social inequalities when it increases the welfare of disadvantaged agents.  相似文献   

Training Interventions to Foster Skill and Will of Argumentative Thinking     

Markus H. Hefter  Alexander Renkl  Werner Riess  Sebastian Schmid  Stefan Fries  Kirsten Berthold 《Journal of Experimental Education》2018,86(3):325-343

Argumentative thinking requires not only the skill to apply argumentative strategies such as supporting theories with evidence but also the will to apply these strategies by considering argumentative thinking to be both reasonable and worthwhile. Focusing on direct instruction for the initial acquisition of both skill and will, we developed a new short-term computer-based training intervention. We tested its effects on learning processes and learning outcomes in an experimental study with 147 German high school students. Our intervention fostered facets of both skill (i.e. a declarative knowledge about argumentation) and will (i.e., epistemic orientation, intellectual values, and epistemic knowledge). We gained additional insights into learning mechanisms, such as the mediating effects of the learners' self-explanation activities and the advantage of addressing will before skill.  相似文献   

Novel self-excited alternating operation of coupled commutator machines     

Markus Zahn  James K. Skinner 《Journal of The Franklin Institute》1973,296(1):1-13

Through the coupling of commutator machines, self-excited alternating power can be spontaneously generated with no external electrical excitations. Standard frequency- domain analysis is applied to the various equivalent circuits for each configuration. Conventional series and shunt self-excited generators are shown to have a single pole in the right-half s plane, indicating growing exponential solutions, whereas coupled generators are shown to have a pair of complex conjugate poles in the right-half s plane, indicating overstable modes, which oscillate as they grow, resulting in self-excited two-phase alternating power generation. Because of this interesting result, the analysis is extended to consider N-coupled generators which shows the existence of many overstable modes, resulting in multi-frequency, multi-phase power generation. The existence of electromechanical alternating self-excitation is demonstrated with the periodic speed reversals of a separately exited d.c. motor, which has its armature in series with the field and armature windings of a generator. Experimental results are presented which indicate that the linear circuit representation is appropriate for the onset and early time interval of these self-excited machines. The magnetic saturation characteristic limits the exponential growth so that a steady state results. These devices are of use in low-frequency, high-power applications, as well as serving as a model for other spontaneous mechanisms in nature.  相似文献   

What determines patent value?: Insights from the semiconductor industry     

Markus Reitzig 《Research Policy》2003,32(1):13-26

This paper contributes to an understanding which impacts certain patent characteristics have on the value of patent rights. In an exploratory study, 127 individual patents from a semiconductor company were evaluated comprehensively by technical and marketing representatives. The analysis of this rare data shows that for patents used as “bargaining chips”, novelty and inventive activity are most important. Difficulty of inventing around and disclosure turn out to be of limited importance. Due to a selection bias the influence of patent age on its value cannot be determined. The results hint at a differentiated theoretical plausibility of value indicators.  相似文献   

Walk this way: validity evidence of iphone health application step count in laboratory and free-living conditions     

Markus J. Duncan  Kelly Wunderlich  Yingying Zhao  Guy Faulkner 《Journal of sports sciences》2018,36(15):1695-1704

Several attempts have been made to demonstrate the accuracy of the iPhone pedometer function in laboratory test conditions. However, no studies have attempted to evaluate evidence of convergent validity of the iPhone step counts as a surveillance tool in the field. This study takes a pragmatic approach to evaluating Health application derived iPhone step counts by measuring accuracy of a standardized criterion iPhone SE and a heterogeneous sample of participant owned iPhones (6 or newer) in a laboratory condition, as well as comparing personal iPhones to accelerometer derived steps in a free-living test. During lab tests, criterion and personal iPhones differed from manually counted steps by a mean bias of less than ±5% when walking at 5km/h, 7.5km/h and 10km/h on a treadmill, which is generally considered acceptable for pedometers. In the free-living condition steps differed by a mean bias of 21.5% or 1340 steps/day when averaged across observation days. Researchers should be cautioned in considering the use of iPhone models as a research grade pedometer for physical activity surveillance or evaluation, likely due to the iPhone not being continually carried by participants; if compliance can be maximized then the iPhone might be suitable.  相似文献   

Parallel assessment of nutrition and activity in athletes: validation against doubly labelled water, 24-h urea excretion, and indirect calorimetry     

Koehler K  Braun H  De Marees M  Fusch G  Fusch C  Mester J  Schaenzer W 《Journal of sports sciences》2010,28(13):1435-1449

The assessment of nutrition and activity in athletes requires accurate and precise methods. The aim of this study was to validate a protocol for parallel assessment of diet and exercise against doubly labelled water, 24-h urea excretion, and respiratory gas exchange. The participants were 14 male triathletes under normal training conditions. Energy intake and doubly labelled water were weakly associated with each other (r = 0.69, standard error of estimate [SEE] = 304 kcal x day(-1)). Protein intake was strongly correlated with 24-h urea (r = 0.89) but showed considerable individual variation (SEE = 0.34 g kg(-1) x day(-1)). Total energy expenditure based on recorded activities was highly correlated with doubly labelled water (r = 0.95, SEE = 195 kcal x day(-1)) but was proportionally biased. During running and cycling, estimated exercise energy expenditure was highly correlated with gas exchange (running: r = 0.89, SEE = 1.6 kcal x min(-1); cycling: r = 0.95, SEE = 1.4 kcal x min(-1)). High exercise energy expenditure was slightly underestimated during running. For nutrition data, variations appear too large for precise measurements in individual athletes, which is a common problem of dietary assessment methods. Despite the high correlations of total energy expenditure and exercise energy expenditure with reference methods, a correction for systematic errors is necessary for the valid estimation of energetic requirements in individual athletes.  相似文献   

Zwischenbetriebliche elektronische Katalogsysteme: Netzwerkstrategische Gestaltungsoptionen und Erfolgsfaktoren     

Judith Gebauer und Markus Raupp 《Informatik - Forschung und Entwicklung》2000,15(4):215-225

Zusammenfassung. Das Internet und darauf aufbauende Technologien er?ffnen neue Potentiale für zwischenbetriebliche Informationssysteme und f?rdern die elektronische Unterstützung von Gesch?ftsbeziehungen. Dabei bleibt jedoch das grunds?tzliche Problem bestehen, da? der Hauptinvestor jeweils eine gewisse Anzahl an Teilnehmern ben?tigt, um eine angemessene Verzinsung der für die Systementwicklung und -implementierung eingesetzten Ressourcen zu erreichen. Da es sich im zwischenbetrieblichen Kontext bei den Transaktionspartnern in der Regel um entscheidungsautonome Organisationseinheiten handelt, kann davon ausgegangen werden, da? die kritische Masse nur dann erreicht wird, wenn sich für die Teilnehmer selbst wiederum eine angemessene Verzinsung der für Anbindung und Systemanpassung notwendigen individuellen Aufwendungen ergibt. Dem Hauptinvestor stehen dabei eine Reihe von Gestaltungsoptionen zur Verfügung, denen jeweils unterschiedliche Erfolgsfaktoren zuzuordnen sind. In der Vergangenheit dominierten einerseits auf Zwang ausgerichtete, stark kompetitive Vorgehensweisen und andererseits kooperative Strategien, wie etwa die freiwillige Beschr?nkung der Anzahl an Zulieferbeziehungen im Rahmen vertrauensbildender Ma?nahmen. Mit dem Aufkommen offener Kommunikationsstandards und neuer Technologien lassen sich diese von relativ geringen zus?tzlichen finanziellen Belastungen gekennzeichneten Strategien m?glicherweise nicht mehr aufrechterhalten, und es wird notwendig, neue Optionen in Betracht zu ziehen, wie etwa die Subventionierung einzelner Systemteilnehmer oder die Verbesserung des Gesamtsystems, die jeweils sowohl kompetitive als auch kooperative Elemente aufweisen. Der vorliegende Beitrag diskutiert diese These am Beispiel zwischenbetrieblicher elektronischer Katalogsysteme, wie sie in jüngster Zeit im Kontext elektronischer Absatz- und Beschaffungssysteme sowie elektronischer M?rkte an Bedeutung gewinnen. Eingegangen am 16. Dezember 1999 / Angenommen am 15. April 2000  相似文献   

Implicit and explicit attitudes towards sport among young elite athletes with high versus low burnout symptoms     

Markus Gerber  Ralf Brand  Franziska Antoniewicz  Sandrine Isoard-Gautheur  Henrik Gustafsson  Renzo Bianchi 《Journal of sports sciences》2019,37(14):1673-1680

The development of cynical attitudes towards elite sport is a core symptom of athlete burnout and has been associated with dropout from elite sport. To date, this phenomenon has mainly been studied by investigating explicit attitudes towards sport, whereas athletes’ automatic evaluations (i.e. implicit attitudes) that have been shown to influence behavior as well were not considered. This study aimed to compare explicit and implicit attitudes towards sport of young elite athletes with high (N = 24) versus low (N = 26) burnout symptoms. Using self-reported measures, general and athlete burnout symptoms were assessed. Additionally, a single-target implicit association test was administered to examine participants’ automatic evaluation of sport. Statistical analysis revealed greater emotional/physical exhaustion and sport devaluation in athletes reporting high compared to low burnout symptoms. Implicit attitudes towards sport did not significantly differ between the groups. Furthermore, no significant correlations were observed between different athlete burnout symptoms and implicit attitudes. Athletes with high burnout symptoms show a tendency to explicitly detach themselves from sport, thus fostering sport devaluation as a core symptom of athlete burnout. However, this process does not seem to be reflected in their implicit attitudes towards sport.  相似文献   

During early to mid adolescence,moderate to vigorous physical activity is associated with restoring sleep,psychological functioning,mental toughness and male gender     

Serge Brand  Nadeem Kalak  Markus Gerber  Peter J. Clough  Sakari Lemola  Dena Sadeghi Bahmani 《Journal of sports sciences》2017,35(5):426-434

Numerous studies showed that regular physical activity (PA) is associated with both favourable and restorative sleep and improved psychological functioning (PF). However, there is little research on the topic covering the early to mid-adolescence period. Moreover, curiosity and exploratory behaviour (CEB) and mental toughness (MT) as a result of PA remains thus far uninvestigated, as do possible gender differences. The aim of the present study was to explore the associations between PA, subjective sleep (sS), PF, CEB, and MT during early to mid-adolescence. A total of 1361 participants (mean age = 13.37 years; range: 11–16 years; 51.2% female) took part in the study. They completed questionnaires covering PA, sS, PF, CEB, and MT. Greater PA was related to improved PF, better sS, and increased CEB and MT. Compared to male participants, females reported less PA, poorer sS, and had lower PF and MT scores. The present pattern of results suggests that during early and mid-adolescence greater PA was associated with more favourable sS and better PF, including CEB and MT, and that female participants reported lower scores in PA, sS, and PF. Accordingly, if PA has a favourable impact on sleep and psychological functioning, then data suggest that sports participation should be more tailored to increase motivation among female adolescents.  相似文献