394 research outputs found
Do Higher Wages Pay for Themselves? An Intra-firm Test of the Effect of Wages on Employee Performance
Conference: AAA 2015 Management Accounting Section (MAS) Meeting, AAA 2015 Annual meeting, Volume: http://ssrn.com/abstract=2482829This study uses field data from 490 hotels in a single lodging chain to investigate three questions
related to the efficiency-wage hypothesis. (1) Does paying workers higher relative wages ex ante
result in better ex post actual performance, either by motivating workers to exert greater effort or
by attracting higher quality workers? (2) Is the magnitude of the relation between performance
and wages the same when workers are overpaid versus underpaid? (3) Do the overall benefits of
paying higher wages outweigh the costs? The data enable us to perform powerful tests of wageperformance
relations because exogenous factors that likely affect employee behavior are
standardized across hotels. Our results suggest that actual performance (measured by customer
satisfaction, revenues, and profit) is increasing in the relative wage, and that higher performance
is the result, and not the cause, of higher wages. We find that the magnitude of the wageperformance
relation is at least as large for workers who are overpaid compared to those who are
underpaid. This result, which differs from the results of experimental studies, suggests that
overpaid workers do not rationalize away wage premiums. Finally, our results indicate that
increases in wages do, in fact, pay for themselves. A 1,080 increase in profit for the mean hotel. This research contributes
to a series of studies that investigates the extent to which wages influence performance (e.g.,
Levine, 1992; Fehr and Falk, 1999; Hannan, Kagal, and Moser, 2002; Hannan, 2005), and
whether the marginal benefit of wage increases justifies their costs (Levin, 1993)
LA DYADE MANAGER – SUPERIEUR : UNE DIMENSION OUBLIEE DU CONTRÔLE DE GESTION
Les termes paradoxe, tension, contradiction ou encore dilemme reviennent régulièrement dans la littérature en management et en contrôle. La forte présence de ces thèmes marque leur importance pour appréhender la complexité de ces activités. Cependant, ces concepts sont souvent utilisés sinon de façon inappropriée, tout du moins avec peu de clarté dans leur définition. Par ailleurs, si les études en management traitent souvent des systèmes et des acteurs, elles s'intéressent rarement à la dyade manager-supérieur. Cette dernière est pourtant l'un des noeuds les plus importants où se forment et se gèrent oppositions, contradictions, paradoxes etc. Ceci nous amène à proposer certaines pistes afin de clarifier le concept de dualité et à étudier dans deux entreprises un exemple de contradiction dans les relations entre managers et supérieurs, celui de l'autonomie et de la direction par le sens. Nous mettons ainsi en évidence le besoin d'une compréhension plus fine des dynamiques interpersonnelles, et non seulement des systèmes de contrôle et des styles de management, dans les problématiques de contrôle.Contradiction; Dyades manager–supérieur hiérarchique; Coadaptation; Management; Contrôle de gestion
Financial consequences of competitive set choice
This study examines the financial consequences of competitive set choice using a sample of 312 hotels in a major metropolitan area in the United States. We document existence of asymmetric competitor monitoring, finding just 55% of monitoring is reciprocal; that is, about half of managers “agree,” by virtue of monitoring one another, on being direct competitors. Monitoring reciprocity is positively associated with performance through average daily rates. With total revenue unchanged, profits are higher through lower occupancy and lower total costs. We examine alternative competitive sets formed using strategic groups- and customer-based approaches, comparing these to actual compsets. We found that performance declines when managers deviate from these alternative sets. Post-hoc analyses provide insight on how overlapping compsets impact rates, occupancy and revenue. Our study is of value to academics and practitioners, providing evidence on the financial impact of competitive monitoring, and insights for managers who choose competitive sets
Genetic control of plasticity of oil yield for combined abiotic stresses using a joint approach of crop modeling and genome-wide association
Understanding the genetic basis of phenotypic plasticity is crucial for
predicting and managing climate change effects on wild plants and crops. Here,
we combined crop modeling and quantitative genetics to study the genetic
control of oil yield plasticity for multiple abiotic stresses in sunflower.
First we developed stress indicators to characterize 14 environments for
three abiotic stresses (cold, drought and nitrogen) using the SUNFLO crop model
and phenotypic variations of three commercial varieties. The computed plant
stress indicators better explain yield variation than descriptors at the
climatic or crop levels. In those environments, we observed oil yield of 317
sunflower hybrids and regressed it with three selected stress indicators. The
slopes of cold stress norm reaction were used as plasticity phenotypes in the
following genome-wide association study.
Among the 65,534 tested SNP, we identified nine QTL controlling oil yield
plasticity to cold stress. Associated SNP are localized in genes previously
shown to be involved in cold stress responses: oligopeptide transporters, LTP,
cystatin, alternative oxidase, or root development. This novel approach opens
new perspectives to identify genomic regions involved in
genotype-by-environment interaction of a complex traits to multiple stresses in
realistic natural or agronomical conditions.Comment: 12 pages, 5 figures, Plant, Cell and Environmen
Sensitivity and specificity of NT-proBNP to detect heart failure at post mortem examination
NT-proBNP, a marker of cardiac failure, has been shown to be stable in post mortem samples. The aim of this study was to assess the accuracy of NT-proBNP to detect heart failure in the forensic setting. One hundred sixty-eight consecutive autopsies were included in the study. NT-proBNP blood concentrations were measured using a chemiluminescent immunoassay kit. Cardiac failure was assessed by three independent forensic experts using macro- and microscopic findings complemented by information about the circumstances of body discovery and the known medical story. Area under the receiving operator curve was of 65.4% (CI 95%, from 57.1 to 73.7). Using a standard cut-off value of >220pg/mL for NT-proBNP blood concentration, heart failure was detected with a sensitivity of 50.7% and a specificity of 72.6%. NT-proBNP vitreous humor values were well correlated to the ones measured in blood (r 2 = 0.658). Our results showed that NT-proBNP can corroborate the pathological findings in cases of natural death related to heart failure, thus, keeping its diagnostic properties passing from the ante mortem to the post mortem setting. Therefore, biologically inactive polypeptides like NT-proBNP seem to be stable enough to be used in forensic medicine as markers of cardiac failure, taking into account the sensitivity and specificity of the tes
Domain-wall motion induced by spin transfer torque delivered by helicity-dependent femtosecond laser
In magnetic wires with perpendicular anisotropy, moving domain with only
current or only circularly polarized light requires a high power. Here, we
propose to reduce it by using both short current pulses and femtosecond laser
pulses simultaneously. The wires were made out of perpendicularly magnetized
film of Pt/Co/Ni/Co/Pt. The displacement of the domain wall is found to be
dependent on the laser helicity. Based on a quantitative analysis of the
current-induced domain wall motion, the spin orbit torque contribution can be
neglected when compared to the spin transfer torque contribution. The effective
field of the spin transfer torque is extracted from the pulsed field domain
wall measurements. Finally, our result can be described using the
Fatuzzo-Labrune model and considering the effective field due to the polarized
laser beam, the effective field due to spin transfer torque, and the Gaussian
temperature distribution of the laser spot.Comment: 14 pages, 4 figure
Evaluation of postmortem measurement of NT-proBNP as a marker for cardiac function
Clinical biomarkers of cardiac function could also be monitored postmortem. Among the natriuretic peptides, the aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be a more reliable postmortem tool than the BNP, owing to its longer half-life and greater stability. In living persons, NT-proBNP is considered to be a marker of heart failure, and its level rises after cardiac ischemia. The goal of this study was first to evaluate the postmortem stability of NT-proBNP, then to measure the NT-proBNP levels in postmortem cases of heart failure related to coronary ischemia. The goal of this study was also to evaluate the correlations between different specimens collected at autopsy (e.g. blood, serum, vitreous humor and pericardial fluid). The study included 96 cases, which were classified into 4 groups according to the autopsy and histological findings. The NT-proBNP levels were significantly higher in individuals who had suffered from chronic cardiac ischemia, with or without acute coronary events, than in either control cases or those who had suffered from acute thromboembolism or acute rupture of a plaque without chronic cardiac ischemia. The highest levels were registered in individuals who had suffered from acute coronary thromboembolism in association with chronic coronary ischemia. Good correlations in the NT-proBNP levels for the different specimens were observed between samples of femoral blood, serum, and pericardial fluid. Our data indicated that postmortem measurements of NT-proBNP are reliable and compatible with clinical finding
Microscopic versus Macroscopic Glass Transitions and Relevant Length Scales in Mixtures of Industrial Interest
We have combined X-ray diffraction, neutron diffraction with polarization analysis, small-angle neutron scattering (SANS), neutron elastic fixed window scans (EFWS), and differential scanning calorimetry (DSC) to investigate polymeric blends of industrial interest composed by isotopically labeled styrene–butadiene rubber (SBR) and polystyrene (PS) oligomers of size smaller than the Kuhn length. The EFWS are sensitive to the onset of liquid-like motions across the calorimetric glass transition, allowing the selective determination of the “microscopic” effective glass transitions of the components. These are compared with the “macroscopic” counterparts disentangled by the analysis of the DSC results in terms of a model based on the effects of thermally driven concentration fluctuations and self-concentration. At the microscopic level, the mixtures are dynamically heterogeneous for blends with intermediate concentrations or rich in PS, while the sample with highest content of the fast SBR component looks as dynamically homogeneous. Moreover, the combination of SANS and DSC has allowed determining the relevant length scale for the α-relaxation through its loss of equilibrium to be ≈30 Å. This is compared with the different characteristic length scales that can be identified in these complex mixtures from structural, thermodynamical, and dynamical points of view because of the combined approach followed. We also discuss the sources of the non-Gaussian effects observed for the atomic displacements and the applicability of a Lindemann-like criterion in these materials.We thank Marc Couty for fruitful discussions and Karine Vernay (Michelin Advanced Research) for dSBR synthesis. The authors acknowledge Grant PID2021-123438NB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, as well as financial support of Eusko Jaurlaritza (code: IT1566-22) and from the IKUR Strategy under the collaboration agreement between Ikerbasque Foundation and the Materials Physics Center on behalf of the Department of Education of the Basque Government. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)
Thermomechanical behavior of C38LTT in the semi-solid state
Semisolid thixoforming is an intermediate process between casting and forging. This process presents several advantages, such as energy efficiency, production rates, smooth die filling, low shrinkage porosity, which together lead to near net shape capability and thus to fewer manufacturing steps than with classical methods. So far, there are only few applications of semisolid processing of higher melting point alloys. Steel is a particularly challenging material to semi-solid process because of the high temperatures involved (about 1410°C). At present, the ability to form steel components in semi-solid state depends on the control of the flow of material during the forming and defects conditions. Semi-solid alloys display thixotropy, which is characterized by time-dependent behavior which drastically changes from a solid like behavior at rest to a liquid like flow when submitted to shear. However, characterizing and modelling such a behaviour for steels is still challenging. Ascometal has developed the C38LTT (Low Thixoforging Temperature) that is compatible with identified parameters [1] to be suitable for thixoforming: the solidus and liquidus temperatures (TS and TL) have to be as low as possible; the temperature at 50% liquid fraction (T50%) has to be as low as possible; the melting interval (TL-TS) has to be as large as possible; and the slope at 10% and 50% liquid fraction must be as low as possible to ensure a small sensitivity of liquid fraction to temperature. The aim of the research work was to study the rheological properties of C38LTT. The high temperature range for semi-solid state makes the experiments particularly challenging. An experimental protocol was determined, geometries of specimens, minimize thermal gradients and optical system to improve the precision of measuring temperature (figure1) with a Gleeble simulator to characterize the thermomechanical behaviors. Uniaxial tensile and compressive tests were carried out on semi-solid specimen having >0.8 solid fraction for different ram speeds and temperatures. The constitutive behavior appears greatly dependent on both fraction solid and strain rate. Furthermore, while the behavior is dominated by the solid phase, the variation in both ductility and stress with temperature has been identified to propose a brittle temperature range and the influence of the temperature on the thermomechanical behavior. Specifically, in tension, a drastic change in ductility with fraction solid/temperature was found in good agreement with some results for aluminum brittle temperature range in literature [2].
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