Investigations regarding the behaviour of historic glass and its surface layers towards different wavelengths applied for laser cleaning     

Farideh Fekrsanati  Stefan Klein  Jens Hildenhagen  Klaus Dickmann  Yiorgos Marakis  Aleka Manousaki  Vassilis Zafiropulos   《Journal of Cultural Heritage》2001,2(4):187

The application of lasers for the removal of superficial deposits from historic stained glass is a comparatively new field of scientific interest. Experimental studies concerning the behaviour of glass substrates and the corresponding superficial deposits towards different laser wavelengths were carried out. The experiments were performed using wavelengths of λ = 193 nm (ArF-Excimer), 308 nm (XeCl-Excimer), 355 nm (Nd:YAG third harmonic) and 1 064 nm (Nd:YAG fundamental) in comparison to λ = 248 nm (KrF-Excimer). This comparison is due to the fact that the present knowledge is based on the 248 nm wavelength. Specially prepared model glass samples representing the original fragments and samples of organic polymers (formerly used as a protective material for historic stained glasses) were used to study the effects of laser radiation and were subsequently characterised by optical microscopy.  相似文献   

Google Scholar and Web of Science: Examining gender differences in citation coverage across five scientific disciplines     

Jens Peter Andersen  Mathias Wullum Nielsen 《Journal of Informetrics》2018,12(3):950-959

Many studies demonstrate differences in the coverage of citing publications in Google Scholar (GS) and Web of Science (WoS). Here, we examine to what extent citation data from the two databases reflect the scholarly impact of women and men differently. Our conjecture is that WoS carries an indirect gender bias in its selection criteria for citation sources that GS avoids due to criteria that are more inclusive. Using a sample of 1250 U.S. researchers in Sociology, Political Science, Economics, Cardiology and Chemistry, we examine gender differences in the average citation coverage of the two databases. We also calculate database-specific h-indices for all authors in the sample. In repeated simulations of hiring scenarios, we use these indices to examine whether women's appointment rates increase if hiring decisions rely on data from GS in lieu of WoS. We find no systematic gender differences in the citation coverage of the two databases. Further, our results indicate marginal to non-existing effects of database selection on women's success-rates in the simulations. In line with the existing literature, we find the citation coverage in WoS to be largest in Cardiology and Chemistry and smallest in Political Science and Sociology. The concordance between author-based h-indices measured by GS and WoS is largest for Chemistry followed by Cardiology, Political Science, Sociology and Economics.  相似文献   

Organismic integration as a dynamic process: a systematic review of empirical studies on change in behavioral regulations in exercise in adults     

Anna Wasserkampf  Jens Kleinert 《International review of sport and exercise psychology》2016,9(1):65-95

In facilitating the adoption of exercise behavior, attention should be directed towards the dynamic nature of behavioral regulations. Organismic integration theory presents a suitable framework for investigating fluctuations in behavioral regulations. However, current results pertaining to this issue revealed mixed findings. The aim of this review is to examine the empirical literature on the dynamic nature of organismic integration theory in exercise settings over time in adults. A systematic review of English articles using PsycINFO, PsycARTICLES, ScienceDirect, and SPORTDiscus was conducted including keywords of organismic integration theory, longitudinal designs, change in behavioral regulations, and exercise. Findings are summarized through quantitative analysis of the evidence. Regarding autonomous regulations, steady increases in regulations are observable that originate within the first weeks and persist for up to one year. Most studies reported no changes in controlled regulations, although in a few cases changes were observed six weeks after baseline or later. The review adds to the theoretical understanding of how behavioral regulations are internalized. However, whether changes in regulation occur depends on both the type of regulation and on contextual characteristics. Future research of longitudinal design is warranted to identify optimal periods in which individuals seek for increased support during exercise adoption.  相似文献   

Spannungsfeld Polyvalenz in der Lehrerbildung     

Dr. Johannes Bauer  Dr. Uta Diercks  Prof. Dr. Jan Retelsdorf  Dr. Tabea Kauper  Dr. Friederike Zimmermann  Prof. Dr. Olaf K?ller  Dr. Jens M?ller  Prof. Dr. Manfred Prenzel 《Zeitschrift für Erziehungswissenschaft》2011,14(4):629-649

The Bologna Process of higher education reform has led to a vast array of different programs of study in German teacher training. In this article, we firstly analyze the implementation of Bachelor programs in teacher training, comparing profession-oriented programs (i.e. those aiming to train students for the teaching profession from the beginning of studies) to polyvalent programs (i.e. those aiming at broad qualifications and including a late decision to become a teacher). Secondly, we investigate whether students enrolled in these study programs differ systematically in their subjective certainty about their career choice. To answer these questions, we analyze portfolios of documents related to teacher training programs from nine German universities that prepare students for teaching in the academic track. Additionally, we analyze data from N?=?2585 Bachelor and N?=?928 Master degree students. We found that most programs, even when they espouse polyvalence, require an early decision to become a teacher. Moreover, our data confirm findings from earlier studies indicating that student teachers are highly certain about their career choice from the very beginning, with students in polyvalent programs being slightly less certain than those in profession-oriented programs (d?=?0.32).  相似文献   

Investigating the relationship between pre-service physics teachers' professional knowledge,self-concept,and interest     

Stefan Sorge  Melanie M. Keller  Knut Neumann  Jens Möller 《科学教学研究杂志》2019,56(7):937-955

This study investigates the relationships between professional knowledge, self-concept, and interest of pre-service physics teachers. In order to support student learning and interest development alike, teachers need a profound professional knowledge and respective motivational orientations. Developing both professional knowledge and motivational orientations in teachers is therefore a key challenge of teacher education. Prior research has focused on the development of content knowledge (CK) and pedagogical content knowledge (PCK) within teacher education, but the role of motivational orientations such as self-concept and interest have mostly been neglected areas of study. As individuals develop domain-specific motivational orientations, they compare their achievement in an external frame to the achievement of their peers, and they compare their achievements in an internal frame across domains. The effects of these psychological processes on domain-specific motivational orientations are described by the generalized internal/external frame of reference model (GI/E model). We assessed the professional knowledge (CK and PCK) and motivational orientations (self-concept and interest) of N = 200 pre-service physics teachers from 12 teacher education institutes in Germany. To investigate the predictions of the GI/E model, we utilized structural equation modeling. In line with the GI/E model, the analysis revealed that pre-service teachers use social comparisons. Pre-service teachers with a higher CK/PCK also showed a higher CK/PCK self-concept. We also identified instances of internal comparisons as we found that a high level of CK corresponds with a lower PCK self-concept. While we could not identify the same effects from professional knowledge on interest, self-concept mediated the effects from professional knowledge on interest. The results suggest that interdependencies between professional knowledge and motivational orientation should be given more consideration in teacher education research and should also be addressed more explicitly in teacher education.  相似文献   

Objektorientierter Entwurf eines flexiblen Workflow-Management-Systems     

Mathias Weske  Jens Hündling  Dominik Kuropka und Hilmar Schuschel 《Informatik - Forschung und Entwicklung》1998,13(4):179-195

Zusammenfassung.   Dieser Beitrag enth?lt die wesentlichen konzeptionellen überlegungen zur Entwicklung eines flexiblen Workflow-Management-Systems. Ausgehend von einer Diskussion m?glicher Modellierungsalternativen wird unter Verwendung objektorientierter Modellierungstechniken ein Workflow-Meta-Schema entwickelt, das die relevanten Entit?ten klassifiziert und ihre Beziehungen abbildet. Anhand eines Beispiels werden die getroffenen Entwurfentscheidungen ausführlich begründet. Schlie?lich werden Zust?nde und Zustandsüberg?nge von Workflow-Instanzen beschrieben, und es wird diskutiert, wie dynamische Ver?nderungen von Workflows zur Laufzeit durchgeführt werden k?nnen, um laufende Workflows dynamisch an ver?nderte Umweltbedingungen anzupassen. Eingegangen am 20. Dezember 1997 / Angenommen am 24. Juli 1998  相似文献   

FOREKOMSTEN AF PSYKISKE LIDELSER BLANDT LÆRERE     

Af overlæge Jens Haslund  og professor Villars Lunn. 《Scandinavian Journal of Educational Research》2013,57(1):266-285

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Zeitökonomische Aspekte der Nachfrage nach Vereinsleichtathletik im europäischen Vergleich     

Dr. phil. Jens Flatau  Werner Pitsch  Dirk Bogendörfer  Eike Emrich 《Sportwissenschaft》2009,39(2):110-119

In a joint project involving European association staff and sports scientists, basic structural data were collected on British, Swedish, Spanish and German athletics clubs to be used for analysis of hypotheses concerning conditions of participation in sports clubs, particularly by children and adolescents. The results showed clear differences in organizational level as well as membership and activity structures in comparisons between European countries and within Germany. The findings revealed the differential functions and significance of sports clubs in the context of the respective institutions and cultures.  相似文献   

Bringing political parties into the picture: a two-dimensional analytical framework for higher education policy     

Jens Jungblut 《Higher Education》2015,69(5):867-882

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„Different Paths up the same Mountain“     

Jens Haaf  Daniel Memmert 《Sportwissenschaft》2006,36(3):352-354

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