832 research outputs found
Estimating the wage premium to supervision for middle managers in different contexts: evidence from Germany and the UK
The analysis of wage distribution has attracted scholars from different disciplines seeking to develop theoretical arguments to explain the upward or downward trend. In particular, how the middle management wage premium changes in different contexts is a relatively neglected area of research. This study argues that wage distribution changes in different contexts, representing different forms of capitalism. To shed light on this, we considered the size and the shape of the wage premium to supervision paid to middle managers in Germany and the UK. We find evidence of two forms of context: middle managers are paid differently for the same task according to the economy where they work; of this amount, about half of the difference is related to the context. We frame the analysis within the literature on varieties of capitalism
Enhanced lipid extraction from unbroken microalgal cells using enzymes
The marine microalga Nannochloropsis sp. was chosen as a model organism to investigate the feasibility of using cell wall-degrading enzymes to enhance the recovery of intracellular lipids. An enzyme cocktail containing galactomannanase, 1,4-β-cellobiosidase and β-glucosidase as main components was prepared from commercial enzyme preparations. The effects of pretreatment time (P), enzyme dosage (D), pH and temperature (T) on the amount of extracted lipids were investigated using response surface methodology. Under the best conditions (P = 90 min, D = 1.3 mg g–1, pH = 5, T = 36°C) over 70% of the lipids present in the microalga were recovered. SEM and TEM characterization of enzyme-treated microalgae showed extensive cell damage with significant disruption of the cell wall and release of algal material. Overall, the results of this study strongly support the use of commercial enzyme preparations to improve lipid recovery from microalgae and provide useful information on the influence of process conditions on the treatment efficiency
On cosmological observables in a swiss-cheese universe
Photon geodesics are calculated in a swiss-cheese model, where the cheese is
made of the usual Friedmann-Robertson-Walker solution and the holes are
constructed from a Lemaitre-Tolman-Bondi solution of Einstein's equations. The
observables on which we focus are the changes in the redshift, in the
angular-diameter--distance relation, in the luminosity-distance--redshift
relation, and in the corresponding distance modulus. We find that redshift
effects are suppressed when the hole is small because of a compensation effect
acting on the scale of half a hole resulting from the special case of spherical
symmetry. However, we find interesting effects in the calculation of the
angular distance: strong evolution of the inhomogeneities (as in the approach
to caustic formation) causes the photon path to deviate from that of the FRW
case. Therefore, the inhomogeneities are able to partly mimic the effects of a
dark-energy component. Our results also suggest that the nonlinear effects of
caustic formation in cold dark matter models may lead to interesting effects on
photon trajectories.Comment: 25 pages, 21 figures; replaced to fit the version accepted for
publication in Phys. Rev.
Competition between intrinsic and extrinsic effects in the quenching of the superconducting state in FeSeTe thin films
We report the first experimental observation of the quenching of the
superconducting state in current-voltage characteristics of an iron-based
superconductor, namely, in FeSeTe thin films. Based on available theoretical
models, our analysis suggests the presence of an intrinsic flux-flow electronic
instability along with non-negligible extrinsic thermal effects. The
coexistence and competition of these two mechanisms classify the observed
instability as halfway between those of low-temperature and of high-temperature
superconductors, where thermal effects are respectively largely negligible or
predominant.Comment: 7 pages, 5 figures, fixed typo
Steaming effects on selected wood properties of Turkey oak by spectral analysis
Turkey oak (Quercus cerris L.) is characterized by some technological and aesthetical factors limiting its market value from its great potential. In this study, the effect of direct and indirect steaming on reduction in equilibrium moisture content (EMC) and colour variations was evaluated using a hyperspectral radiometer.
Steaming treatments were carried out at 80C for 48 h, and 120C for 18 and 24 h, showing a reduction in EMC in the order of 8.1, 28.5 and 13.5, respectively, as well as very significant lightness (L*) and hue (h) modifications in comparison with untreated specimens. The spectral signature analysis confirmed that hydrothermal treatments modify wood sensibility to the light source in the entire spectrum range.
The study supports the validity of hydrothermal treatments for improving technological and aesthetical properties of Turkey oak
Stability mechanisms of high current transport in iron-chalcogenides superconducting films
The improvement in the fabrication techniques of iron-based superconductors
have made these materials real competitors of high temperature superconductors
and MgB. In particular, iron-chalcogenides have proved to be the most
promising for the realization of high current carrying tapes. But their use on
a large scale cannot be achieved without the understanding of the current
stability mechanisms in these compounds. Indeed, we have recently observed the
presence of flux flow instabilities features in Fe(Se,Te) thin films grown on
CaF. Here we present the results of current-voltage characterizations at
different temperatures and applied magnetic fields on Fe(Se,Te) microbridges
grown on CaF. These results will be analyzed from the point of view of the
most validated models with the aim to identify the nature of the flux flow
instabilities features (i.e., thermal or electronic), in order to give a
further advance to the high current carrying capability of iron-chalcogenide
superconductors.Comment: 4 pages, 3 figure
A Methodology to Evaluate the Effects of Kinematic Measurement Uncertainties on Knee Ligament Properties Estimated from Laxity Measurements
Cardiovascular abnormalities and impaired exercise performance in adolescents with congenital adrenal hyperplasia
Context: Patients with classic Congenital Adrenal Hyperplasia (CAH) are treated with lifelong glucocorticoids (GCS). Cardiovascular (CV) and metabolic effects of such therapy in adolescents have never been quantified. Objective: To investigate left ventricular (LV) morphology, function and exercise performance in adolescents with CAH. Design and Setting: cross-sectional and controlled study conducted at a tertiary referral centre. Patients: Twenty patients with classic CAH (10 females) aged 13.6±2.5 years and 20 healthy controls comparable for sex and pubertal status were enrolled in the study and compared to a group of 18 patients without CAH receiving a similar dose of GCS for Juvenile Idiopathic Arthritis (JIA). Main Outcomes Measures: Echocardiographic assessment and symptom-limited exercise testing were performed. Anthropometric, hormonal and biochemical parameters were also measured. Results: Compared to healthy controls, patients with CAH exhibited an increased BMI (p<0.001), waist-to-height ratio (p<0.001), percentage of body fat (p<0.001) as well as higher insulin concentrations and HOMA index even after adjustment for BMI (p=0.03 and p=0.05, respectively). Moreover, CAH patients exhibited an impaired exercise capacity as shown by reduced peak workload (99±27 vs 126±27 W, p<0.01) and higher systolic blood pressure response at peak (156±18 vs 132±11 mmHg, p<0.01; Δ=45±24 vs 22±10 mmHg, p=0.05) with respect to healthy controls. CAH males displayed mild LV diastolic dysfunction as documented by significant prolongation of both isovolumic relaxation time (IRT) (118±18 vs 98±11ms, p<0.05) and mitral deceleration time (MDT) (138±25 vs 111±15 ms, p<0.01). No significant differences in CV function were found between CAH and JIA patients. Conclusion: Adolescents with CAH exhibit impaired exercise performance and enhanced systolic blood pressure response during exercise. In our population, such abnormalities appear related to GCS therapy rather than CAH per se. CAH males, but no females, present mild LV diastolic dysfunction that correlates with testosterone concentrations suggesting a sex hormone related difference
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