On the validity of subjective measures of company performance

Subjective measures of company performance are widely used in research and typically are interpreted as equivalent to objective measures. Yet, the assumption of equivalence is open to challenge. We compared the use of both types of measure in 3 separate samples. Findings were consistent in showing that: (a) subjective and objective measures of company performance were positively associated (convergent validity); (b) those relationships were stronger than those between measures of differing aspects of performance using the same method (discriminant validity); and (c) the relationships of subjective and objective company performance measures with a range of independent variables were equivalent (construct validity).

Range of validity of weakly non-linear theory in Rayleigh-Bénard problem

In this paper we examine the equilibrium states of finite amplitude flow in a horizontal fluid layer with differential heating between the two rigid boundaries. The solutions to the Navier-Stokes equations are obtained by means of a perturbation method for evaluating the Landau constants and through a Newton-Raphson iterative method that results from the Fourier expansion of the solutions that bifurcate above the linear stability threshold of infinitesimal disturbances. The results obtained from these two different methods of evaluating the convective flow are compared in the neighborhood of the critical Rayleigh number. We find that for small Prandtl numbers the discrepancy of the two methods is noticeable. © 2009 The Physical Society of Japan.

Range of validity of weakly non-linear theory in Rayleigh-Bénard convection

In this paper we examine the equilibrium states of periodic finite amplitude flow in a horizontal channel with differential heating between the two rigid boundaries. The solutions to the Navier-Stokes equations are obtained by means of a perturbation method for evaluating the Landau coefficients and through a Newton-Raphson iterative method that results from the Fourier expansion of the solutions that bifurcate above the linear stability threshold of infini- tesimal disturbances. The results obtained from these two different methods of evaluating the convective flow are compared in the neighbourhood of the critical Rayleigh number. We find that for small Prandtl numbers the discrepancy of the two methods is noticeable.

Design and validity of a miniaturized open-field aberrometer

PURPOSE: To validate a new miniaturised, open-field wavefront device which has been developed with the capacity to be attached to an ophthalmic surgical microscope or slit-lamp. SETTING: Solihull Hospital and Aston University, Birmingham, UK DESIGN: Comparative non-interventional study. METHODS: The dynamic range of the Aston Aberrometer was assessed using a calibrated model eye. The validity of the Aston Aberrometer was compared to a conventional desk mounted Shack-Hartmann aberrometer (Topcon KR1W) by measuring the refractive error and higher order aberrations of 75 dilated eyes with both instruments in random order. The Aston Aberrometer measurements were repeated five times to assess intra-session repeatability. Data was converted to vector form for analysis. RESULTS: The Aston Aberrometer had a large dynamic range of at least +21.0 D to -25.0 D. It gave similar measurements to a conventional aberrometer for mean spherical equivalent (mean difference ± 95% confidence interval: 0.02 ± 0.49D; correlation: r=0.995, p<0.001), astigmatic components (J0: 0.02 ± 0.15D; r=0.977, p<0.001; J45: 0.03 ± 0.28; r=0.666, p<0.001) and higher order aberrations RMS (0.02 ± 0.20D; r=0.620, p<0.001). Intraclass correlation coefficient assessments of intra-sessional repeatability for the Aston Aberrometer were excellent (spherical equivalent =1.000, p<0.001; astigmatic components J0 =0.998, p<0.001, J45=0.980, p<0.01; higher order aberrations RMS =0.961, p<0.001). CONCLUSIONS: The Aston Aberrometer gives valid and repeatable measures of refractive error and higher order aberrations over a large range. As it is able to measure continuously, it can provide direct feedback to surgeons during intraocular lens implantations and corneal surgery as to the optical status of the visual system.

The N-terminus of CD14 acts to bind apoptotic cells and confers rapid-tethering capabilities on non-myeloid cells:CD14 and rapid tethering of apoptotic cells

Cell death and removal of cell corpses in a timely manner is a key event in both physiological and pathological situations including tissue homeostasis and the resolution of inflammation. Phagocytic clearance of cells dying by apoptosis is a complex sequential process comprising attraction, recognition, tethering, signalling and ultimately phagocytosis and degradation of cell corpses. A wide range of molecules acting as apoptotic cell-associated ligands, phagocyte-associated receptors or soluble bridging molecules have been implicated within this process. The role of myeloid cell CD14 in mediating apoptotic cell interactions with macrophages has long been known though key molecules and residues involved have not been defined. Here we sought to further dissect the function of CD14 in apoptotic cell clearance. A novel panel of THP-1 cell-derived phagocytes was employed to demonstrate that CD14 mediates effective apoptotic cell interactions with macrophages in the absence of detectable TLR4 whilst binding and responsiveness to LPS requires TLR4. Using a targeted series of CD14 point mutants expressed in non-myeloid cells we reveal CD14 residue 11 as key in the binding of apoptotic cells whilst other residues are reported as key for LPS binding. Importantly we note that expression of CD14 in non-myeloid cells confers the ability to bind rapidly to apoptotic cells. Analysis of a panel of epithelial cells reveals that a number naturally express CD14 and that this is competent to mediate apoptotic cell clearance. Taken together these data suggest that CD14 relies on residue 11 for apoptotic cell tethering and it may be an important tethering molecule on so called 'non-professional' phagocytes thus contributing to apoptotic cell clearance in a non-myeloid setting. Furthermore these data establish CD14 as a rapid-acting tethering molecule, expressed in monocytes, which may thus confer responsiveness of circulating monocytes to apoptotic cell derived material. © 2013 Thomas et al.

Case Comment : Challenging the validity of leasehold guarantees:undue influence, non-est factum and formality issues

Case: Beardsley Theobalds Retirement Benefit Scheme Trustees v Yardley [2011] EWHC 1380 (QB) (QBD). The recent case of Beardsley Theobalds Retirement Benefit Scheme Trustees v Yardley, nicely illustrates, inter alia, the impact of the contractual defences of undue influence and the plea of non est factum in the context of avoiding liability under leasehold guarantees, within the setting of the landlord and tenant relationship. Additionally, the case also gives us an insight into the possible application of other technical defences relating to the law of formalities for leases. Judgment in this case was handed down on September 30, 2011.

Validity of a prototype surgical aberrometer

Poster Purpose: A study to validate a prototype Hartmann-Shack (HS) wavefront aberrometer. Methods: The dynamic range was assessed using a calibrated model eye. It was validated against a conventional HS-aberrometer (Topcon KR1W) in 75 eyes using both instruments in random order. Additionally, intra-sessional repeatability was tested. Results: The aberrometer showed a large dynamic range of +21.0 D to −25.0 D. It was comparable to a conventional HS aberrometer for spherical-equivalent SE (MD ± 95% CI: 0.02 ± 0.49D; correlation: r = 0.995, p < 0.001), astigmatic components (J0: 0.02 ± 0.15D; r = 0.977, p < 0.001; J45: 0.03 ± 0.28; r = 0.666, p < 0.001) and HOAs RMS (0.02 ± 0.20D; r = 0.620, p < 0.001). Intra-sessional repeatability correlation was also excellent (SE = 1.000, p < 0.001; astigmatic-components J0 = 0.998, p < 0.001, J45 = 0.980, p < 0.01; HOAs RMS = 0.961, p < 0.001). Conclusions: This study confirms the validity of the prototype aberrometer. The prototype aberrometer can measure continuously to provide direct feedback of the optical status of the eye during surgery.

Peripheral refraction validity of the Shin-Nippon SRW5000 autorefractor

PURPOSE: To investigate the operation of the Shin-Nippon/Grand Seiko autorefractor and whether higher-order aberrations affect its peripheral refraction measurements. METHODS: Information on instrument design, together with parameters and equations used to obtain refraction, was obtained from a patent. A model eye simulating the operating principles was tested with an optical design program. Effects of induced defocus and astigmatism on the retinal image were used to calibrate the model eye to match the patent equations. Coma and trefoil were added to assess their effects on the image. Peripheral refraction of a physical model eye was measured along four visual field meridians with the Shin-Nippon/Grand Seiko autorefractor SRW-5000 and a Hartmann-Shack aberrometer, and simulated autorefractor peripheral refraction was derived using the Zernike coefficients from the aberrometer. RESULTS: In simulation, the autorefractor's square image was changed in size by defocus, into rectangles or parallelograms by astigmatism, and into irregular shapes by coma and trefoil. In the presence of 1.0 D oblique astigmatism, errors in refraction were proportional to the higher-order aberrations, with up to 0.8 D sphere and 1.5 D cylinder for ±0.6 μm of coma or trefoil coefficients with a 5-mm-diameter pupil. For the physical model eye, refraction with the aberrometer was similar in all visual field meridians, but refraction with the autorefractor changed more quickly along one oblique meridian and less quickly along the other oblique meridian than along the horizontal and vertical meridians. Simulations predicted that higher-order aberrations would affect refraction in oblique meridians, and this was supported by the experimental measurements with the physical model eye. CONCLUSIONS: The autorefractor's peripheral refraction measurements are valid for horizontal and vertical field meridians, but not for oblique field meridians. Similar instruments must be validated before being adopted outside their design scope.

A cross-cultural study of factors influencing helping behaviour

The burgeoning research into altruism and helping behaviour has examined the effect of many variables that enhance or inhibit helpfulness, but little attention has been given to the influence of culture. In the present research, data on various aspects of helping behaviour were collected in both the UK and the Sudan so that the importance of cultural influences could be investigated. In addition this research also tested the validity of current models of helping. In a repertory grid study, urgency and cost emerged as the main constructs people in the two countries use to distinguish between various helpful situations. A laboratory experiment designed to test existing models of intervention behaviour found significant main effects of country, group, size, cost and urgency; and a group size/urgency interaction. Subjects in the Sudan intervened faster than subjects in the UK; lone subjects intervened faster than subjects in small and large groups; subjects in low cost intervened faster than subjects in high cost conditions; and subjects in high urgency intervened faster than subjects in low urgency conditions. Group size effect was stronger in low than in high urgency conditions. Two field studies further investigated the effect of urgency and cost in urban-nonurban context. Significant main effects of urgency and cost were found in cities but not in towns; and people in cities were less helpful than people in towns. A questionnaire survey found that in both countries there were significant urban-nonurban differences in the incidence of reported social contacts and exchange of helpful acts between acquaintances, neighbours and strangers. However, there were no urban-nonurban differences between relatives and close friends. Finally, attitudes to altruism and helpfulness did not differ between the two countries or between urban and nonurban residents. The results highlight the need to incorporate urgency and cultural variables in theoretical models of helping behaviour.

Measuring employee innovation:a review of existing scales and the development of the innovative behavior and innovation support inventories across cultures

Purpose - The paper develops a model of employee innovative behavior conceptualizing it as distinct from innovation outputs and as a multi-faceted behavior rather than a simple count of ‘innovative acts’ by employees. It understands individual employee innovative behaviors as a micro-foundation of firm intrapreneurship that is embedded in and influenced by contextual factors such as managerial, organizational and cultural support for innovation. Building from a review of existing employee innovative behavior scales and theoretical considerations we develop and validate the Innovative Behavior Inventory (IBI) and the Innovation Support Inventory (ISI). Design/methodology/approach – Two pilot studies, a third validation study in the Czech Republic and a fourth cross-cultural validation study using population representative samples from Switzerland, Germany, Italy and the Czech Republic (N=2812 employees and 450 entrepreneurs) were conducted. Findings - Both inventories were reliable and showed factorial, criterion, convergent and discriminant validity as well as cross-cultural equivalence. Employee innovative behavior was supported as comprising of idea generation, idea search, idea communication, implementation starting activities, involving others and overcoming obstacles. Managerial support was the most proximal contextual influence on innovative behavior and mediated the effect of organizational support and national culture. Originality/value - The paper advances our understanding of employee innovative behavior as a multi-faceted phenomenon and the contextual factors influencing it. Where past research typically focuses on convenience samples within a particular country, we offer first robust evidence that our model of employee innovative behavior generalizes across cultures and types of samples. Our model and the IBI and ISI inventories enable researchers to build a deeper understanding of the important micro-foundation underpinning intrapreneurial behavior in organizations and allow practitioners to identify their organizations’ strengths and weaknesses related to intrapreneurship.