Bestimmungsgründe des betrieblichen Ausbildungsverhaltens in Deutschland

Die vorliegende Arbeit untersucht die theoretischen Erklärungsansätze für das betriebliche Ausbildungsverhalten auf ihre empirische Evidenz. Als Datensatz wird das IAB-Betriebspanel aus dem Jahr 2000 verwen-det. Gegenstand der Analyse bilden die beiden Fragen nach den Bestimmungsgründen von Ausbildungsbeteiligung (soll ausgebildet werden?) sowie Ausbildungsumfang (wie viele Lehrlinge?). Die gewonnen Befunde deuten darauf hin, dass das betriebliche Ausbildungsverhalten mit Hilfe des produktionstheoretischen, investitionstheoretischen und Reputationsansatzes auf ein ökonomisches Kalkül zurückgeführt werden kann. Eine trennscharfe Überprüfung dieser drei Motive ist jedoch nicht möglich, da ein Großteil der signifikanten Einflussvariablen nicht nur mit einem der Erklärungsansätze vereinbar ist.This paper empirically investigates theoretical explanations for the firms' training decisions using the IAB-Establishment Panel data for the year 2000. Both the determinants of firms' participation in vocational training (should training be provided at all?) and of the extent of training (how many apprenticeships?) are analyzed. The results suggest that firms' training behaviour reflects an economic reasoning that takes into account production motives, investment motives and reputation motives. However, the empirical findings do not allow us to clearly discriminate between these three motives since most of the significant covariates are consistent with not just one of the theoretical approaches

Bestimmungsgründe des betrieblichen Ausbildungsverhaltens in Deutschland

Die vorliegende Arbeit untersucht die theoretischen Erklärungsansätze für das betriebliche Ausbildungsverhalten auf ihre empirische Evidenz. Als Datensatz wird das IAB-Betriebspanel aus dem Jahr 2000 verwen-det. Gegenstand der Analyse bilden die beiden Fragen nach den Bestimmungsgründen von Ausbildungsbeteiligung (soll ausgebildet werden?) sowie Ausbildungsumfang (wie viele Lehrlinge?). Die gewonnen Befunde deuten darauf hin, dass das betriebliche Ausbildungsverhalten mit Hilfe des produktionstheoretischen, investitionstheoretischen und Reputationsansatzes auf ein ökonomisches Kalkül zurückgeführt werden kann. Eine trennscharfe Überprüfung dieser drei Motive ist jedoch nicht möglich, da ein Großteil der signifikanten Einflussvariablen nicht nur mit einem der Erklärungsansätze vereinbar ist. -- This paper empirically investigates theoretical explanations for the firms? training decisions using the IAB-Establishment Panel data for the year 2000. Both the determinants of firms? participation in vocational training (should training be provided at all?) and of the extent of training (how many apprenticeships?) are analyzed. The results suggest that firms' training behaviour reflects an economic reasoning that takes into account production motives, investment motives and reputation motives. However, the empirical findings do not allow us to clearly discriminate between these three motives since most of the significant covariates are consistent with not just one of the theoretical approaches.Betriebliche Ausbildung,Lehrstellenangebot,Produktionstheoretischer Ansatz,Investitionstheoretischer Ansatz,Reputationsansatz

Betriebliches Ausbildungsverhalten zwischen Kosten-Nutzen-Kalkül und gesellschaftlicher Verantwortung: Einflussfaktoren der Ausbildungsintensität von deutschen Betrieben

Theoretische Überlegungen und empirische Analysen auf Basis einer Befragung von 35 Ausbildungsbetrieben in Bayern zeigen, dass der Beschäftigtenanteil von Auszubildenden mit der Betriebsgröße und den Bruttokosten einer Ausbildung tendenziell abnimmt. Besonders intensiv bilden Betriebe im Falle eines Fachkräftemangels aus und falls extern Ausgebildete eine längere Einarbeitungszeit aufweisen als selbst Ausgebildete. Dies deutet darauf hin, dass die Ausbildungsentscheidungen der Arbeitgeber weniger kurzfristiges Kostendenken als vielmehr langfristige Humankapitalinvestitionen widerspiegeln. Weitere von den Befragten genannten Ausbildungsmotive sind die Tradition des Betriebes sowie die Schaffung eines guten Rufes am Arbeitsmarkt, doch kann der letztere Einfluss ökonometrisch nicht bestätigt werden. -- Theoretical considerations and empirical analyses based on a survey of 35 establishments in Bavaria show that the employment share of apprentices tends to fall with firm size and with the gross costs of vocational training. Establishments are particularly engaged in training if they experience a shortage of skilled labour and if employees hired from the external labour market have a longer settling-in period than own trainees. This indicates that employers decisions on vocational training mainly reflect long-term investments in human capital rather than short-term cost considerations. Other motives mentioned by the establishments surveyed are the firms tradition and the aim of obtaining a good labour market reputation, but this influence cannot be confirmed econometrically.Betriebliche Ausbildung,Fachkräftebedarf,Humankapital

Betriebliches Ausbildungsverhalten zwischen Kosten-Nutzen-Kalkül und gesellschaftlicher Verantwortung: Einflussfaktoren der Ausbildungsintensität von deutschen Betrieben

Theoretische Überlegungen und empirische Analysen auf Basis einer Befragung von 35 Ausbildungsbetrieben in Bayern zeigen, dass der Beschäftigtenanteil von Auszubildenden mit der Betriebsgröße und den Bruttokosten einer Ausbildung tendenziell abnimmt. Besonders intensiv bilden Betriebe im Falle eines Fachkräftemangels aus und falls extern Ausgebildete eine längere Einarbeitungszeit aufweisen als selbst Ausgebildete. Dies deutet darauf hin, dass die Ausbildungsentscheidungen der Arbeitgeber weniger kurzfristiges Kostendenken als vielmehr langfristige Humankapitalinvestitionen widerspiegeln. Weitere von den Befragten genannten Ausbildungsmotive sind die Tradition des Betriebes sowie die Schaffung eines guten Rufes am Arbeitsmarkt, doch kann der letztere Einfluss ökonometrisch nicht bestätigt werden.Theoretical considerations and empirical analyses based on a survey of 35 establishments in Bavaria show that the employment share of apprentices tends to fall with firm size and with the gross costs of vocational training. Establishments are particularly engaged in training if they experience a shortage of skilled labour and if employees hired from the external labour market have a longer settling-in period than own trainees. This indicates that employers' decisions on vocational training mainly reflect long-term investments in human capital rather than short-term cost considerations. Other motives mentioned by the establishments surveyed are the firm's tradition and the aim of obtaining a good labour market reputation, but this influence cannot be confirmed econometrically

Physiologically Based Simulations of Deuterated Glucose for Quantifying Cell Turnover in Humans.

In vivo [6,6-(2)H2]-glucose labeling is a state-of-the-art technique for quantifying cell proliferation and cell disappearance in humans. However, there are discrepancies between estimates of T cell proliferation reported in short (1-day) versus long (7-day) (2)H2-glucose studies and very-long (9-week) (2)H2O studies. It has been suggested that these discrepancies arise from underestimation of true glucose exposure from intermittent blood sampling in the 1-day study. Label availability in glucose studies is normally approximated by a "square pulse" (Sq pulse). Since the body glucose pool is small and turns over rapidly, the availability of labeled glucose can be subject to large fluctuations and the Sq pulse approximation may be very inaccurate. Here, we model the pharmacokinetics of exogenous labeled glucose using a physiologically based pharmacokinetic (PBPK) model to assess the impact of a more complete description of label availability as a function of time on estimates of CD4+ and CD8+ T cell proliferation and disappearance. The model enabled us to predict the exposure to labeled glucose during the fasting and de-labeling phases, to capture the fluctuations of labeled glucose availability caused by the intake of food or high-glucose beverages, and to recalculate the proliferation and death rates of immune cells. The PBPK model was used to reanalyze experimental data from three previously published studies using different labeling protocols. Although using the PBPK enrichment profile decreased the 1-day proliferation estimates by about 4 and 7% for CD4 and CD8+ T cells, respectively, differences with the 7-day and 9-week studies remained significant. We conclude that the approximations underlying the "square pulse" approach-recently suggested as the most plausible hypothesis-only explain a component of the discrepancy in published T cell proliferation rate estimates

A search for interstellar anthracene toward the Perseus anomalous microwave emission region

We report the discovery of a new broad interstellar (or circumstellar) band at 7088.8 +- 2.0 \AA coincident to within the measurement uncertainties with the strongest band of the anthracene cation (C$_{14}$H$_{10}$$^+$) as measured in gas-phase laboratory spectroscopy at low temperatures (Sukhorukov et al.2004). The band is detected in the line of sight of star Cernis 52, a likely member of the very young star cluster IC 348, and is probably associated with cold absorbing material in a intervening molecular cloud of the Perseus star forming region where various experiments have recently detected anomalous microwave emission. From the measured intensity and available oscillator strength we find a column density of N$_{an^+}$= 1.1(+-0.4) x 10$^{13}$ cm$^{-2}$ implying that ~0.008% of the carbon in the cloud could be in the form of C$_{14}$H$_{10}$$^+$. A similar abundance has been recently claimed for the naphthalene cation (Iglesias-Groth et al. 2008) in this cloud. This is the first location outside the Solar System where specific PAHs are identified. We report observations of interstellar lines of CH and CH$^+$ that support a rather high column density for these species and for molecular hydrogen. The strength ratio of the two prominent diffuse interstellar bands at 5780 and 5797 \AA suggests the presence of a ``zeta'' type cloud in the line of sight (consistent with steep far-UV extinction and high molecular content). The presence of PAH cations and other related hydrogenated carbon molecules which are likely to occur in this type of clouds reinforce the suggestion that electric dipole radiation from fast spinning PAHs is responsible of the anomalous microwave emission detected toward Perseus.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Time-dependent density functional study of the electronic spectra of oligoacenes in the charge states -1, 0, +1, and +2

We present a systematic theoretical study of the five smallest oligoacenes (naphthalene, anthracene, tetracene, pentacene, and hexacene) in their anionic,neutral, cationic, and dicationic charge states. We used density functional theory (DFT) to obtain the ground-state optimised geometries, and time-dependent DFT (TD-DFT) to evaluate the electronic absorption spectra. Total-energy differences enabled us to evaluate the electron affinities and first and second ionisation energies, the quasiparticle correction to the HOMO-LUMO energy gap and an estimate of the excitonic effects in the neutral molecules. Electronic absorption spectra have been computed by combining two different implementations of TD-DFT: the frequency-space method to study general trends as a function of charge-state and molecular size for the lowest-lying in-plane long-polarised and short-polarised $\pi\to\pi^\star$ electronic transitions, and the real-time propagation scheme to obtain the whole photo-absorption cross-section up to the far-UV. Doubly-ionised PAHs are found to display strong electronic transitions of $\pi\to\pi^\star$ character in the near-IR, visible, and near-UV spectral ranges, like their singly-charged counterparts. While, as expected, the broad plasmon-like structure with its maximum at about 17-18 eV is relatively insensitive to the charge-state of the molecule, a systematic decrease with increasing positive charge of the absorption cross-section between about 6 and about 12 eV is observed for each member of the class.Comment: 38 pages, 11 figures, 7 tables, accepted for publication in Chemical Physic

Human neutrophil kinetics: modeling of stable isotope labeling data supports short blood neutrophil half-lives.

Human neutrophils have traditionally been thought to have a short half-life in blood; estimates vary from 4-18 hours. This dogma was recently challenged by stable isotope labeling studies with heavy water which yielded estimates in excess of 3 days. To investigate this disparity we generated new stable isotope labeling data in healthy adult subjects using both heavy water (n=4) and deuterium-labeled glucose (n=9), a compound with more rapid labeling kinetics. To interpret results we developed a novel mechanistic model. We applied this model to both previously-published (n=5) and newly-generated data. We initially constrained the ratio of the blood neutrophil pool to the marrow precursor pool (R=0.26, from published values). Analysis of heavy water datasets yielded turnover rates consistent with a short blood half-life, but parameters, particularly marrow transit-time, were poorly-defined. Analysis of glucose-labeling data yielded more precise estimates of half-life, 0.79 ± 0.25 days (19 hours), and marrow transit-time, 5.80 ± 0.42 days. Substitution of this marrow transit-time in the heavy water analysis gave a better-defined blood half-life, 0.77 ± 0.14 days (18.5 hours), close to glucose-derived values. Allowing R to vary yielded a best-fit value, R=0.19. Reanalysis of the previously-published model and data also revealed the origin of their long estimates for neutrophil half-life, an implicit assumption that R is very large, which is physiologically untenable. We conclude that stable isotope labeling in healthy humans is consistent with a blood neutrophil half-life of less than one day

Dynamically simulating the interaction of midazolam and the CYP3A4 inhibitor itraconazole using individual coupled whole-body physiologically-based pharmacokinetic (WB-PBPK) models

BACKGROUND: Drug-drug interactions resulting from the inhibition of an enzymatic process can have serious implications for clinical drug therapy. Quantification of the drugs internal exposure increase upon administration with an inhibitor requires understanding to avoid the drug reaching toxic thresholds. In this study, we aim to predict the effect of the CYP3A4 inhibitors, itraconazole (ITZ) and its primary metabolite, hydroxyitraconazole (OH-ITZ) on the pharmacokinetics of the anesthetic, midazolam (MDZ) and its metabolites, 1' hydroxymidazolam (1OH-MDZ) and 1' hydroxymidazolam glucuronide (1OH-MDZ-Glu) using mechanistic whole body physiologically-based pharmacokinetic simulation models. The model is build on MDZ, 1OH-MDZ and 1OH-MDZ-Glu plasma concentration time data experimentally determined in 19 CYP3A5 genotyped adult male individuals, who received MDZ intravenously in a basal state. The model is then used to predict MDZ, 1OH-MDZ and 1OH-MDZ-Glu concentrations in an CYP3A-inhibited state following ITZ administration. RESULTS: For the basal state model, three linked WB-PBPK models (MDZ, 1OH-MDZ, 1OH-MDZ-Glu) for each individual were elimination optimized that resulted in MDZ and metabolite plasma concentration time curves that matched individual observed clinical data. In vivo K(m )and V(max )optimized values for MDZ hydroxylation were similar to literature based in vitro measures. With the addition of the ITZ/OH-ITZ model to each individual coupled MDZ + metabolite model, the plasma concentration time curves were predicted to greatly increase the exposure of MDZ as well as to both increase exposure and significantly alter the plasma concentration time curves of the MDZ metabolites in comparison to the basal state curves. As compared to the observed clinical data, the inhibited state curves were generally well described although the simulated concentrations tended to exceed the experimental data between approximately 6 to 12 hours following MDZ administration. This deviations appeared to be greater in the CYP3A5 *1/*1 and CYP3A5 *1/*3 group than in the CYP3A5 *3/*3 group and was potentially the result of assuming that ITZ/OH-ITZ inhibits both CYP3A4 and CYP3A5, whereas in vitro inhibition is due to CYP3A4. CONCLUSION: This study represents the first attempt to dynamically simulate metabolic enzymatic drug-drug interactions via coupled WB-PBPK models. The workflow described herein, basal state optimization followed by inhibition prediction, is novel and will provide a basis for the development of other inhibitor models that can be used to guide, interpret, and potentially replace clinical drug-drug interaction trials

Current trends in drug metabolism and pharmacokinetics.

Pharmacokinetics (PK) is the study of the absorption, distribution, metabolism, and excretion (ADME) processes of a drug. Understanding PK properties is essential for drug development and precision medication. In this review we provided an overview of recent research on PK with focus on the following aspects: (1) an update on drug-metabolizing enzymes and transporters in the determination of PK, as well as advances in xenobiotic receptors and noncoding RNAs (ncRNAs) in the modulation of PK, providing new understanding of the transcriptional and posttranscriptional regulatory mechanisms that result in inter-individual variations in pharmacotherapy; (2) current status and trends in assessing drug-drug interactions, especially interactions between drugs and herbs, between drugs and therapeutic biologics, and microbiota-mediated interactions; (3) advances in understanding the effects of diseases on PK, particularly changes in metabolizing enzymes and transporters with disease progression; (4) trends in mathematical modeling including physiologically-based PK modeling and novel animal models such as CRISPR/Cas9-based animal models for DMPK studies; (5) emerging non-classical xenobiotic metabolic pathways and the involvement of novel metabolic enzymes, especially non-P450s. Existing challenges and perspectives on future directions are discussed, and may stimulate the development of new research models, technologies, and strategies towards the development of better drugs and improved clinical practice