Search results for "Complex."
showing 10 items of 5824 documents
Regression with imputed covariates: A generalized missing-indicator approach
2011
A common problem in applied regression analysis is that covariate values may be missing for some observations but imputed values may be available. This situation generates a trade-off between bias and precision: the complete cases are often disarmingly few, but replacing the missing observations with the imputed values to gain precision may lead to bias. In this paper, we formalize this trade-off by showing that one can augment the regression model with a set of auxiliary variables so as to obtain, under weak assumptions about the imputations, the same unbiased estimator of the parameters of interest as complete-case analysis. Given this augmented model, the bias-precision trade-off may the…
Do robots complement or substitute for older workers?
2021
Abstract The impact of robotization on labor market outcomes has been recently empirically investigated along several directions, including employment, wages and labor productivity. This work contributes to this literature by looking for heterogeneous effects of robots on the workforce, analyzed by age cohorts. Relying on a panel of data from IFR (2019) and EU KLEMS (2009) over the years 1994–2005, we find consistent evidence of higher complementarity between robots and older workers (hours worked by employees aged 50 and over), and a greater substitutability among robots and younger cohorts of the labor market. These findings are robust to age group disaggregation and specific capital pric…
Complexity in project co-creation of knowledge for innovation
2020
The European Union (EU) promotes collaboration across functions and borders in its funded innovation projects, which are seen as complex collaboration to co-create knowledge. This requires the engagement of multiple stakeholders throughout the duration of the project. To probe complexity in EU-funded innovation projects the research question is: How does complexity affect the co-creation of knowledge in innovation projects, according to project participants? The data for this study was collected from project experts in the form of short narratives, using a questionnaire based on the elements of complexity of Mitleton-Kelly (2003). The results indicate that complexity characterises the co-cr…
Family governance systems: the complementary role of constitutions and councils
2021
The understanding of family businesses from the family side is still in its infancy. This is especially true in relation to how family members manage their relationships with one another and with the firm. Family growth and evolution are usually accompanied by a reduction in shared family meaning and purpose and greater divergence in the form of factional interests and intentions that harm the family and the firm. To counterbalance this negative impact, scholars generally advocate a set of corporate governance practices. However, few papers have analysed how family regulatory frameworks and family governance institutions affect family firm performance. To the best of our knowledge, no paper…
Community currency (CCs) in Spain: An empirical study of their social effects
2016
Despite its sudden proliferation along the economic crisis period, no previous study has investigated the social effects of the community currency (CCs) experiences in Spain. Previous research on CCs experiences from different countries provided evidences about social capital improvement, introducing CCs as sustainability tools. This research uses the theoretical frameworks of social capital and complex adaptive systems to approach concepts like sustainability, networks, trust, norms, participation and cooperation. Statistical analysis of the data collected in June 2013 through online survey explores social capital and resilience indicators among the Spanish exchange community users, conclu…
When financial economics influences physics: The role of Econophysics
2019
This paper aims at analyzing the unexpected influence of Financial economics on Physics. The rise of Econophysics, a fundamentally new approach in finance, suggests that the influence between the two disciplines becomes less unilateral than in the past. Methodological debates emerging in Econophysics led physicists to acknowledge that dealing with financial complex systems contributed to a wider modelling of their field. The approach of econophysicists suggests that physicists might try to conceptualize physical phenomena by integrating elements they faced with in Financial economics, and more generally in Economics. Surprisingly, many of econophysicists’ argumentations have some methodolog…
When Financial Economics Influences Physics: The Role of Econophysics
2018
This paper aims at analyzing the unexpected influence of Financial economics on Physics. The rise of Econophysics, a fundamentally new approach in finance, suggests that the influence between the two disciplines becomes less unilateral than in the past. Methodological debates emerging in Econophysics led physicists to acknowledge that dealing with financial complex systems contributed to a wider modelling of their field. The approach of econophysicists suggests that physicists might try to conceptualize physical phenomena by integrating elements they faced with in Financial economics, and more generally in Economics. Surprisingly, many of econophysicists’ argumentations have some methodolog…
The modulation of immune complex aggregation by classical pathway-mediated reactions.
1985
Abstract Classical pathway (CP)-triggered reactions of complement-modulated immune complex(IC) aggregation (tetanus toxoid/human anti-tetanus toxoid-IgG; ICs of equivalence) were investigated turbidimetrically during the early stages of reaction. Monospecific Fab'- or Fab-fragments (rabbit) directed against certain complement components were used to block the complement function in normal human serum (NHS). Additionally, parts of the reactions were studied using purified complement components. C1q in serum generated by the addition of EDTA as well as purified C1q were found to increase the IC aggregation. In contrast to C1q, macromolecular C1 is able to inhibit IC aggregation, whereas addit…
Differential activation of human γ δ cells by nonpeptide phosphoantigens
2001
Human T cells expressing Vγ9/Vδ2-encoded TCR recognize several nonpeptide phosphoantigens in the absence of major histocompatibility complex restriction. As these cells respond differentially to increasing concentrations of structurally related phosphoantigens, such ligands constitute agonists of different strengths. By analyzing early cellular events and late effector responses of γ δ T cells, we compared their patterns of stimulation by weak, medium and strong phosphoantigen agonists. We found that, although the early metabolic activation as assessed by cytosensormicrophysiometry directly reflects the intensity of subsequent effector response by γ δ cells, TCR down-modulation is dissociat…
Development and optimization of confirmatory liquid chromatography—Orbitrap mass spectrometry method for the determination of 17 anticoccidials in po…
2018
A new sensitive and selective multi-residue method based on liquid chromatography - Orbitrap high resolution mass spectrometry (LC-Orbitrap-HRMS) was developed and validated for the determination of 17 anticoccidials in poultry and eggs. Instrumental parameters were optimized by the means of statistical experimental designs to improve the sensitivity, precision, and repeatability of the method. Further optimization of auto-tuned MS parameters led to an increase of signal intensity by 10% to 99% for 16 out of 17 analytes. The sample preparation procedure included extraction from muscle tissue and egg samples with acetonitrile, followed by preconcentration, reconstitution, and filtration. Val…