Die vorliegende Arbeit untersucht die Testteilnahmemotivation von Schülerinnen und Schülern in großangelegten Schulleistungsstudien. Es wurde ein theoretisches Erwartung-Wert-Anstrengung-Modell der Testteilnahmemotivation herausgearbeitet, das in drei empirischen Studien überprüft wurde. Dabei wurde das komplexe Beziehungsgefüge zwischen Erfolgserwartung, dem wahrgenommene Wert des Tests, Anstrengungsbereitschaft und Testleistung untersucht. Datengrundlage der Studie I bildete die erste PISA-Erhebung aus dem Jahr 2000, in der die Testteilnahmemotivation durch Fragen zur Anstrengungsbereitschaft und zum wahrgenommenen Wert des Tests erhoben wurde. In Studie II und III gaben die Jugendlichen, die an der Ländervergleichsstudie im Jahr 2012 teilnahmen, Einschätzungen zu ihrer Erfolgserwartung, dem wahrgenommenen Wert des Tests und ihrer Anstrengungsbereitschaft ab. Die Ergebnisse zeigen, dass Testteilnahmemotivation zur Erklärung individueller Unterschiede in der Testleistung beiträgt (Studie I), auch wenn diverse Hintergrundinformationen der Teilnehmenden berücksichtigt werden (Studie III). Die theoretisch angenommenen Beziehungen im Erwartung-Wert-Anstrengung-Modell wurden fast vollständig bestätigt: Vor allem der wahrgenommene Wert, aber auch die Erwartungen sagten die berichtete Anstrengungsbereitschaft der Teilnehmenden vorher; die Erfolgserwartung und die Anstrengungsbereitschaft wiesen einen Zusammenhang mit der Testleistung auf (Studie II). Im Verlauf eines Leistungstests berichteten die Teilnehmenden im Durchschnitt eine Abnahme in der Anstrengung und dem Wert sowie einen stabilen Verlauf ihrer Erfolgserwartung. Zur Erklärung der Testleistung trug neben der anfänglichen Erfolgserwartung und Anstrengungsbereitschaft auch die Veränderung in der Erfolgserwartung bei (Studie III). Für eine hohe Testleistung ist es wichtig, dass die Teilnehmenden den Test motiviert beginnen und während des Tests selbstsicher bezüglich ihrer Erfolgserwartung bleiben. / The thesis investigates effects of test-taking motivation on test performance in low-stakes assessments. An expectancy-value-effort model of test-taking motivation was developed and tested in three empirical studies. The studies investigated the complex relationship between expectancy for success, perceived value of the test, test-taking effort, and test performance. The database of study I is the first PISA study. Test-taking motivation was assessed with questions about effort and the perceived value of the test. Study II and III are premised on the national assessment study in the year 2012. The students reported their expectancy for success, their perceived value of the test, and their test-taking effort. Overall, the results showed that test-taking motivation explained test performance (study I) although controlling for various students’ background characteristics (e.g., socio-economic background, study III). We found support for nearly all of the theoretically assumed relationships in the expectancy-value-effort model: Expectancy for success and perceived value of the test explained test-taking effort; expectancy for success and test-taking effort had the most pronounced effects on test performance (study II). The students reported, on average, a stable course of expectancy for success over the testing session; perceived importance of the test and test-taking effort slightly decreased within the testing session. The initial expectancy for success and the initial test-taking effort as well as change in expectancy for success explained students’ test performance. Above all, it is crucial that students begin the test with a high level of test-taking motivation and remain confident about a successful test completion to the end of the testing session.

A major argument for incorporating deciduous tree species in coniferous forest stands is their role in the amelioration and stabilisation of biogeochemical cycles. Current forest management strategies in central Europe aim to increase the area of mixed stands. In order to formulate statements about the ecological effects of mixtures, studies at the stand level are necessary. In a mixed stand of Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) in the Ore Mountains (Saxony, Germany), the effects of these two tree species on chemical and microbial parameters in the topsoil were studied at one site in the form of a case study. Samples were taken from the O layer and A horizon in areas of the stand influenced by either birch, spruce or a mixture of birch and spruce. The microbial biomass, basal respiration, metabolic quotient, pH-value and the C and N contents and stocks were analysed in the horizons Of, Oh and A. Significantly higher contents of microbial N were observed in the Of and Oh horizons in the birch and in the spruce-birch strata than in the stratum containing only spruce. The same was found with respect to pH-values in the Of horizon and basal respiration in the Oh horizon. Compared to the spruce stratum, in the birch and spruce-birch strata, significantly lower values were found for the contents of organic C and total N in the A horizon. The findings of the case study indicated that single birch trees have significant effects on the chemical and microbial topsoil properties in spruce-dominated stands. Therefore, the admixture of birch in spruce stands may distinctly affect nutrient cycling and may also be relevant for soil carbon sequestration. Further studies of these functional aspects are recommended.

No description available.

Geosorption processes play an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this study influence of pH and NOM on the sorption of three different phenols (2-methyl-4,6-dinitrophenol, 2,4,6-trichlorophenol and pentachlorophenol) on a natural sandy aquifer material collected from a bank filtration site was studied in flow through column experiments. In first step the sorption coefficients of investigated phenols from NOM-free solutions with different pH values were determined. Single as well as multi (mixed) solutes experiments confirmed that there was no competition effect among the phenols investigated. An increasing sorption/retardation was observed with decreasing pH. A linear model was used to resolve the apparent sorption coefficient into an ionised species and neutral species component. This model allows a prediction of apparent sorption coefficients for any pH value. Analysis of data also revealed that the anion of 2-M-4,6-DNP show no significant sorption and a simple model based on the neutral form sorption coefficient was useful in predicting the apparent sorption coefficient over the entire pH range investigated. For 2,4,6-TCP and PCP, the anion sorption is much lower than that of the neutral species but cannot be neglected completely. For PCP, the anion sorption is even as high as the sorption of neutral 2,4,6-TCP. Thus for such hydrophobic phenols prediction of sorption based only on the partitioning of non-dissociated species may lead to an error, especially at high pH values (> pKa), where ionised form is present predominantly. On the other hand prediction of sorption based on the partitioning of non-dissociated species is useful at pH < pKa or in cases where the anion sorption can be neglected. The advantage of this prediction is that it allows predicting the pH-dependent sorption only on the basis of LFER correlations. It was shown that the organic carbon normalized sorption coefficients of the neutral forms of the phenols can be predicted better by solubility based regression correlations than by n-octanol-water partition coefficient based correlations. In second step the apparent sorption coefficients of investigated phenols from NOM-containing solutions (mixed solution of phenols dissolved in natural river water) with different pH values were determined; the sorption coefficients obtained from this step were compared with the results of the first step examinations. Analysis of data revealed that binding of 2-M-4,6-DNP by dissolved humic substances (DHS) reduces the sorption coefficient significantly. In contrast to it, the sorption of the more hydrophobic chlorinated phenols was not affected by DHS. A strong reduction of sorption onto aquifer material caused by complex formation with DHS was also observed for a second nitrophenol (2,4-DNP) and seems to be typically for nitrophenols. A combined sorption and complex formation model was proposed which could be used successfully to describe the effect of pH and NOM concentration on sorption reduction and to estimate binding constants. The binding constant found for 2-M-4,6-DNP is much higher than those reported by Ohlenbusch and Frimmel, 2001, for chlorophenols associated with Aldrich humic acid. This can be interpreted as a result of specific interactions between the nitrophenol and DHS. This phenomenon may cause an increase of the amount of nitrophenols, which can be transported with the groundwater flow and has to be considered in transport modelling, especially in cases where pH is lower than pKa. The models developed here are a useful tool to describe the influence of pH and NOM on geosorption processes and to estimate the Kd values which have to be used in transport models.

This dissertation is an inquiry into the concept of value creation, motivated by a need for orientation in our demanding times. Based on the idea that true value only arises out of human (inter)subjective evaluations, we apply a psychological perspective on individual and collective value creation, thereby investigating a micro-foundation of value, as well as its application and operationalization. The dissertation is a cumulative dissertation that begins with an introductory chapter followed by four independent, yet connected studies. In Study 1, we develop a conceptual foundation for all other studies that involves a micro-foundation of value and value awareness as the competency to recognize fundamental evaluation categories as relevant. In Study 2, we conceptually delineate organizational public value and organizational reputation, two concepts of strategic relevance to organizations, that share similarities, but differ in fundamental dimensions. In Study 3 we operationalize value awareness through a practice-oriented instrument that helps individuals reflect, understand and develop their value awareness. In Study 4, we empirically investigate the link of an organization’s corporate social responsibility and work addiction via work meaningfulness and organizational identification, as well as value awareness. The studies are diverse and have multiple implications for research and practice. Overall, we suggest that individuals and collective entities should develop and operationalize their consideration of value creation on the level of (inter)subjective human experience. To realize actual value creation, many additional factors are important, but more value awareness could play a central role in increasing the chances of finding and creating more value for ourselves, others, and society as a whole.:INTRODUCTION Abstract Motivation and Purpose Theoretical Basis Research Objectives and Studies Excursion: The Leipzig Leadership Model Discussion of Findings Implications for Research Implications for Practice Conclusion References STUDY 1: MORE VALUE AWARENESS FOR MORE (PUBLIC) VALUE: RECOGNIZING HOW AND FOR WHOM VALUE IS TRULY CREATED 68 Abstract STUDY 2: SAME SAME BUT DIFFERENT: THE RELATIONSHIP BETWEEN ORGANIZATIONAL REPUTATION AND ORGANIZATIONAL PUBLIC VALUE Abstract Introduction Organizational Public Value and Organizational Reputation Comparing Public Value and Reputation Implications Conclusion References STUDY 3: THE VALUE AWARENESS PROFILE AS A NEW INSTRUMENT FOR INCREASING INDIVIDUAL VALUE AWARENESS: FOUNDATIONS AND FIRST EXPERIENCES Zusammenfassung Einleitung Theoretische Grundlagen: Wertschöpfung und Wertbewusstsein Wertbewusstsein messen und schaffen: Das Value Awareness Profile Evaluierung des Instruments auf Basis erster Anwendungserfahrungen Ergebnisdarstellung, Typifikation und Hypothesen Diskussion Fazit Literaturverzeichnis STUDY 4: TOO MUCH OF A GOOD THING? ON THE RELATIONSHIP BETWEEN CSR AND EMPLOYEE WORK ADDICTION Abstract Introduction The Positive Outcomes and Potential Risks of CSR for Employees Work Addiction: The Best-Dressed Mental Health Problem in Business Development of Hypotheses Method Results Discussion and Conclusion References

In dieser Untersuchung wurden Daten zur Nährstoff- und Humusversorgung sowie zur Fruchtfolgegestaltung von ökologisch wirtschaftenden Landwirtschaftsbetrieben im Freistaat Sachsen über einen Zeitraum von 6 Jahren gesammelt und ausgewertet. Insgesamt stand Datenmaterial von 810 ökologisch bewirtschaften Acker- und Grünlandschlägen und mehr als 4.800 Ernten zur Verfügung. Die Beurteilung des Nährstoff- und Humusmanagement erfolgte auf Schlag- und Betriebsebene für den pH-Wert und die Grundnährstoffe des Bodens. Ergänzend wurden Nährstoff- und Humusbilanzen sowie der Düngebedarf mit dem Programm BEFU, Teil Ökolandbau, berechnet. Für die Beurteilung des Fruchtfolgemanagements wurde ein geeignetes Bewertungsverfahren entwickelt und angewendet, mit dem der Erfüllungsgrad von Aufgaben und Regeln der Fruchtfolgegestaltung durch leicht erfass- und überprüfbare Kriterien abgeschätzt werden konnte.:1 Einleitung und Problemstellung 2 Material und Methoden 2.1 Datengrundlage 2.2 Bewertung des Nährstoff- und Humusmanagements 2.3 Bewertung der Fruchtfolgegestaltung 2.4 Statistische Verrechnung 3 Ergebnisse 3.1 Analyse des Nährstoff- und Anbaumanagements auf Betriebsebene 3.2 Schlagbezogene Bewertung des Nährstoff- und Anbaumanagements 3.3 Betriebsvergleich der schlagbezogenen Bewertung 4 Diskussion und Schlussfolgerungen 4.1 Methodik 4.2 Nährstoff- und Humusmanagement der Betriebe 4.3 Fruchtfolgegestaltung der Betriebe 5 Zusammenfassung 6 Literaturverzeichnis

(English): In the face of the scandal arising from the persistence of numerous systems of oppression in our time, which ravage and enslave both human beings and other species, often in a cumulative manner: capitalist, patriarchal, racist-colonial, rationalist-ableist and anthropocentrist-productivist systems, the so-called "post-modern" theories fail as well to provide emancipatory analyses and ways out of these systems of domination as do the "traditional Marxist" and classical anarchist theories, because all these theories lack a radical critique of the basic categories of capitalism-patriarchy that only the "value-dissociation critique" offers (at least as far as we are aware of). Since the mid-1980s and with a feminist turn in 1992, first in Germany and then also in Brazil and many other countries, the philosophical current of the "critique of value-dissociation" has been working to rethink a critical theory of patriarchal capitalism based on a radical overcoming of the whole "traditional Marxism". This is done by demonstrating the urgent need to deploy a critique of the basic categories of capitalism, namely work, value, money, commodities, fetishism, patriarchy, and the state; of these categories themselves, and not simply of their phenomenal forms. But how can a critical theory of such power...

Annually, about 40-60 million tons of postharvest straw are generated in Vietnam. Although considered as renewable resources and economic goods, straw is still burned in the field because there is no longer needed for cooking, roofing and fodder as before 1990s. The general economic development of the country and the rural area changed all the previous practices of using straw. This paper analyzes the socio-economic and technical causes of this phenomenon and summarizes the economic and environmentally friendly uses of rice straw in the future. In addition, it points out that policy failures in the management of straw currently exist and that policies for integrated straw management are needed to improve the value chain in the supply and consumption of straw products; to enhance the effectively use of this resource and minimize environmental pollution. / Hàng năm phát sinh khoảng 40-60 triệu tấn rơm sau thu hoạch ở Việt Nam. Mặc dù được coi là tài nguyên tái tạo và hàng hóa kinh tế, song rơm vẫn bị đốt bỏ ở ngoài ruộng do không còn nhu cầu nhiều cho đun nấu, lợp mái nhà và chăn nuôi như trước những năm 1990. Tình hình phát triển kinh tế chung của đất nước và khu vực nông thôn đã làm thay đổi tất cả thói quen dùng rơm rạ trước đây. Bài báo này phân tích một cảnh tổng quan những nguyên nhân kinh tế - xã hội và kỹ thuật dẫn đến hiện tượng này, tổng hợp những khả năng sử dụng kinh tế và thân thiện môi trường của rơm rạ trong tương lai. Ngoài ra chỉ ra những thất bại về chính sách trong quản lý rơm rạ hiện nay và cần có các chính sách quản lý tổng hợp rơm rạ để nâng cao chuỗi giá trị trong cung ứng và tiêu thụ các sản phẩm rơm rạ, tăng cường việc sử dụng có hiệu quả tài nguyên này và giảm thiểu ô nhiễm môi trường.

No description available.

No description available.