In this study, equations are developed that predict for synthetic sedimentary rocks (clastics, carbonates and evapourates) thermal properties comprising thermal conductivity, specific heat capacity ...and thermal diffusivity. The rock groups are composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities of 0–30 per cent. Petrophysical properties and their well-logging-tool-characteristic readings were assigned to these rock-forming minerals and to pore-filling fluids. Relationships are explored between each thermal property and other petrophysical properties (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) using multivariate statistics. The application of these relations allows computing continuous borehole profiles for each rock thermal property. The uncertainties in the prediction of each property vary depending on the selected well-log combination. Best prediction is in the range of 2–8 per cent for the specific heat capacity, of 5–10 per cent for the thermal conductivity, and of 8–15 for the thermal diffusivity, respectively. Well-log derived thermal conductivity is validated by laboratory data measured on cores from deep boreholes of the Danish Basin, the North German Basin, and the Molasse Basin. Additional validation of thermal conductivity was performed by comparing predicted and measured temperature logs. The maximum deviation between these logs is <3 °C. The thermal-conductivity calculation allowed an evaluation of the depth range in which the palaeoclimatic effect on the subsurface temperature field can be observed in the North German Basin. This effect reduces the surface heat-flow density by 25 mW m−2.
Vocational education is seen as beneficial for the labor market allocation of young people. However, recent studies point to disadvantages later in the life course, where the specific skills that are ...obtained from vocational education decrease employability. This paper re-evaluates this hypothesis for the Netherlands with an improved measure for the vocational specificity of educational programs, utilizing both vertical (level) and horizontal (field) information on education. More specifically, we use a gradual measure for the linkage strength between education and occupation to predict employment over the life course. Using data from the national Dutch labor force surveys, we show that there is considerable heterogeneity in occupational specificity within the categories of vocational and general educational programs that is masked when using a dichotomous classification of general versus vocational education. In the life course analyses we find that the large early benefits of having vocational education disappear later in the career and turn into a small disadvantage before retirement.
•We investigate if the returns to a vocational degree varies over the life cycle.•Instead of using a binary indicator of vocational versus general, we use a continuous measure of occupational specificity.•Specificity varies considerably within categories of vocational and general education.•More occupation specific education is beneficial for employment chances of young workers.•Specific education leads to a small employment penalty at the end of the labor market career.
Abstract
This study investigates whether families navigate educational institutions more successfully if they have a higher knowledge of the pathways in the educational system that are available to ...their children. We also study whether this kind of knowledge mediates secondary effects of social origin, i.e. differences in educational pathways once achievement differences between children are accounted for. The role of parents’ knowledge is consistent with various sociological theories concerning educational inequality. Knowledge can affect families’ ability to make rational choices for education but it can also be understood as a form of cultural capital. We use longitudinal student cohort data from the Netherlands combined with individual-level register data on educational attainment to study the importance of knowledge for short-term outcomes (up- and downward transitions in secondary education as well as track placement) and final educational attainment. Our results show that parents’ knowledge is a significant predictor of educational success net of parents’ education, socio-demographic characteristics, and demonstrated ability. If we apply a stricter test to the measure, however, we can see that knowledge matters for downward transitions and obtaining a tertiary degree but that the effect is negligible for upward transitions and track placement if other mechanisms such as cultural capital and aspirations are considered. Further, we conclude that knowledge matters especially for transitions in the educational system that require a move to a new and unknown school environment such as post-secondary or tertiary education. The study shows that knowledge is one useful avenue to investigate when we are confronted with the question why social disparities in educational decision-making arise.
In various educational systems, students are sorted into separate secondary schools on the basis of their academic ability. Research suggests that this type of tracking impacts students' educational ...expectations, as expectations generally align with students' ability track. However, most research is cross‐sectional and students with lower expectations are possibly also sorted into lower tracks. Moreover, the extent to which track placement influences expectations may vary across students. In this paper, we address the following research question: how does ability tracking impact the development of student expectations and how does this vary by students' migration background. Based on the literature on the immigrant aspiration–achievement paradox, we expect that students with a migration background are less likely to adapt expectations downwardly, and more likely to adapt expectations upward in response to track placement. Using German panel data, we examine the educational expectations of students with and without a migration background, before and after track placement. Moreover, we use variations in tracking procedures across German states to study how students who get tracked compare with students who do not get tracked in the development of their educational expectations. We show that students are more likely to upwardly adjust their expectations when their track placement exceeds their expectations and to downwardly adjust their expectations when their track placement is below their expectations. We find little support for the hypothesized variations by student migration background. Students whose parent(s) hold (a) Bachelor degree(s) are more likely to upwardly adjust their expectations when their track placement exceeds their expectations than students whose parent(s) maximally hold an upper secondary or vocational degree(s).
The responsibilities of nurse managers are complex. Their actions are crucial to providing the best possible care to patients and to the success of health care organizations. Thus, nurse managers' ...work engagement is essential. However, understanding of the antecedents of nurse managers' work engagement is lacking. The job demands-resources theory posits that work engagement is contingent upon job resources and demands. Therefore, the aim of this study was to explore which job demands and resources exert a major influence on nurse managers' work engagement. Considering the literature, job resources and demands potentially relevant to nurse managers' work engagement were identified. To investigate the associations between these potential antecedents and nurse managers' work engagement, the study employed a cross-sectional survey. The dataset for analyses comprised 408 nurse managers in Germany and was analyzed by multiple linear regression. The study variables accounted for 26% of the variance in nurse managers' work engagement. Positive associations were detected between the job resource of empowering leadership and nurse managers' work engagement. Regarding job demands, lack of formal rewards and work-life interferences had negative effects on work engagement. The findings suggest that the job demands-resources theory can explain nurse managers' work engagement. However, not all job resources and demands considered were determined to be influential. In conclusion, empowering leadership should be promoted in the work environment of nurse managers. Nurse managers should be provided engaging financial and nonfinancial rewards. Work-life interferences should be systematically mitigated.
Vocationally educated individuals often find employment sooner after school than those with a general educational qualification. A recent study has argued that the higher employment probability ...associated with a vocational qualification reverses in later life. The main explanation is that although having (occupation-)specific skills is an advantage when entering the labor market, specific skills also make the vocationally educated less flexible. This life cycle effect is hypothesized to be especially strong in countries where the vocational system provides highly occupation-specific skills. We test these two hypotheses on cross-national data from PIAAC 2012. Using logistic regressions with country fixed effects, we find that individuals with a vocational qualification have a higher employment probability than those with a general qualification at the start of their career, but this pattern reverses in later life. In contrast to earlier findings, we do not find that this effect varies systematically across countries with different vocational educational systems.
The joint research project CLEAN was conducted in the years 2008–2011 by a German research and development (R&D) alliance of 16 partners from science and industry. The project was set-up as pilot ...project to investigate the processes relevant to enhanced gas recovery (EGR) by the injection of CO₂ into a subfield of the almost depleted Altmark natural gas field. Despite the setback that permission for active injection was not issued by the mining authority during the period of the project, important results fostering the understanding of processes linked with EGR were achieved. Work carried out led to a comprehensive evaluation of the EGR potential of the Altmark field and the Altensalzwedel subfield in particular. The calculated safety margins emphasize that technical well integrity of the 12 examined boreholes is given for EGR without a need for any further intervention. The laboratory and field tests confirm that the Altensalzwedel subfield is suitable for the injection of 100,000 t of CO₂. Numerical simulations provide sound predictions for the efficiency and safety of the EGR technology based on the CO₂ injection. The development and testing of different monitoring techniques facilitate an improved surveying of CO₂ storage sites in general. The CLEAN results provide the technological, logistic and conceptual prerequisites for implementing a CO₂-based EGR project in the Altmark and provide a benchmark for similar projects in the world.
The study examines the adaptation of educational expectations. It focuses on the expectations that parents have of their children during the transition from primary to secondary school in Germany. ...During this transition, students are placed into different ability tracks. It is examined whether parents react to this information about their child's achievement by adjusting their educational expectations or whether their expectations are nonreactive to the achievement information conveyed by track placement. It is hypothesized that parents are more likely to adapt their expectations regarding final educational attainment if their child's track placement is not consistent with the expectations that they held before the track placement was known. Furthermore, SES differences in this adjustment process are expected as parents of different social status have different orientations towards achievement information. The study uses data from the National Educational Panel Study (NEPS), Starting Cohort 2 and focuses on the years between the third grade of primary school and fifth grade, which is the first year of secondary school. This means that students and parents can be followed across the moment in the academic career at which track placement happens. Furthermore, the variations in the tracking decisions across the German federal states is used to examine how the adaptation of parents’ expectations is affected based on how much influence parents have on track placement. Two-way fixed effect models are employed to model the change of expectations between the two time points in the data. The results show that low-SES parents do adjust their expectations more strongly downward when their children receive a lower track placement than expected; however, high-SES parents maintain their high expectations even in light of such negative achievement information. High- and low-SES parents do not significantly differ in their expectation adjustment if their children's track placement is higher than their previous expectations.
► We compare the most common matrix-pore models for thermal conductivity calculation. ► The geometric mean model shows the best fit between measured and calculated values. ► Correction equations ...improve the goodness of fit; the resulting errors are lower than 10%. ► Conversion equations allow a calculation of water-saturated BTC only from dry measurements.
Different numerical models can be deployed to calculate the matrix thermal conductivity of a rock from the bulk thermal conductivity (BTC), if the effective porosity of the rock is known. Vice versa, using these parameters, the BTC can be determined for saturation fluids of different thermal conductivity (TC). In this paper, the goodness-of-fit between measured and calculated BTC values of sedimentary rocks has been evaluated for two-component (rock matrix and pores) models that are used widely in geothermics: arithmetic mean, geometric mean, harmonic mean, Hashin and Shtrikman mean, and effective-medium theory mean. The examined set of samples consisted of 1147 TC data in the interval 1.0–6.5Wm−1K−1. The quality of fit was studied separately for the influence of lithotype (sandstone, mudstone, limestone, dolomite), saturation fluid (water and isooctane), and rock anisotropy (parallel and perpendicular to bedding). From the studied models, the geometric mean displays the best, however not satisfying correspondence between calculated and measured BTC. To improve the fit of all models, respective correction equations are calculated. The “corrected” geometric mean provides the most satisfying results and constitutes a universally applicable model for sedimentary rocks. In addition, the application of the herein presented correction equations allows a significant improvement of the accuracy of existing BTC data calculated on the basis of the other mean models. Finally, lithotype-specific conversion equations are provided permitting a calculation of the water-saturated BTC from data of dry-measured BTC and porosity (e.g., well log derived porosity) with no use of any mixing model. For all studied lithotypes, these correction and conversion equations usually reproduce the BTC with an uncertainty<10%.
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