Utility Analysis for Multiple Selection Devices and Multiple Outcomes

Traditional utility analysis only calculates the value of a given selection procedure over random selection. This assumption is not only an inaccurate representation of staffing policy but leads to overestimates of a device\u27s value. This paper generates a new utility model that accounts for multiple selection devices and multiple criteria. The model is illustrated using previous utility analysis work and an actual case of secretarial employees with eight predictors and nine criteria. A final example also is provided which includes these advancements as well as other researchers\u27 advances in a combined utility model. Results reveal that accounting for multiple criteria and outcomes dramatically reduces the utility estimates of implementing new selection devices

Is It Worth It To Win The Talent War? Evaluating the Utility of Performance-Based Pay

While the business press suggests that “winning the talent war,” the attraction and retention of key talent, is increasingly pivotal to organization success, executives often report that their organizations do not fare well on this dimension. We demonstrate how, through integrating turnover and compensation research, the Boudreau and Berger (1985) staffing utility framework can be used by industrial/organizational (I/O) psychologists and other human resource (HR) professionals to address this issue. Employing a step-by-step process that combines organization-specific information about pay and performance with research on the pay-turnover linkage, we estimate the effects of incentive pay on employee separation patterns at various performance levels. We then use the utility framework to evaluate the financial consequences of incentive pay as an employee retention vehicle. The demonstration illustrates the limitations of standard accounting and behavioral cost-based approaches and the importance of considering both the costs and benefits associated with pay-for-performance plans. Our results suggest that traditional accounting or behavioral cost-based approaches, used alone, would have supported rejecting a potentially lucrative pay-for-performance investment. Additionally, our approach should enable HR professionals to use research findings and their own data to estimate the retention patterns and subsequent financial consequences of their existing, and potential, company-specific performance-based pay policies

Wavelet analysis of atmospheric turbulence over a coral reef flat

The world’s tropical coral reefs are at risk of severe bleaching episodes and species decline in response to global climate variability. The ecological and economic value of reef ecosystems is enormous, yet very little is known of the physical interactions that take place at the coral–ocean–atmosphere interfaces. This paper introduces and validates a novel technique for the acquisition of surface energy balance measurements over Heron Reef, part of the Capricorn Bunker Group of the southern Great Barrier Reef, Australia. Measurements of surface energy and radiation exchanges were made using a Campbell Scientific eddy covariance (EC) measurement system mounted on a floating pontoon anchored to the reef flat. A Nortek Vector velocimeter was positioned next to the pontoon to record wave motion. Wavelet analysis techniques were used to decompose the turbulent exchange of sensible heat measured by the EC unit and to compare vertical velocity measurements with wave-induced motion recorded by the velocimeter. The results indicate that although the EC system and the velocimeter share intermittent periods of high common power in their respective wavelet variance spectra, these regions are not coherent and differ in strength by more than an order of magnitude. It was concluded that over a standard averaging period of 30 min the wave-induced motion of the pontoon would not significantly interfere with the acquisition and calculation of turbulent fluxes of sensible and latent heat, thereby confirming the robustness of this method of obtaining surface energy balance measurements over coral reefs

Direct current driven by ac electric field in quantum wells

It is shown that the excitation of charge carriers by ac electric field with zero average driving leads to a direct electric current in quantum well structures. The current emerges for both linear and circular polarization of the ac electric field and depends on the field polarization and frequency. We present a micoscopic model and an analytical theory of such a nonlinear electron transport in quantum wells with structure inversion asymmetry. In such systems, dc current is induced by ac electric field which has both the in-plane and out-of-plane components. The ac field polarized in the interface plane gives rise to a direct current if the quantum well is subjected to an in-plane static magnetic field.Comment: 6 pages, 3 figure

Asymmetry of Nonlinear Transport and Electron Interactions in Quantum Dots

The symmetry properties of transport beyond the linear regime in chaotic quantum dots are investigated experimentally. A component of differential conductance that is antisymmetric in both applied source-drain bias V and magnetic field B, absent in linear transport, is found to exhibit mesoscopic fluctuations around a zero average. Typical values of this component allow a measurement of the electron interaction strength.Comment: related papers at http://marcuslab.harvard.ed

Signature of the electron-electron interaction in the magnetic field dependence of nonlinear I-V characteristics in mesoscopic systems

We show that the nonlinear I-V characteristics of mesoscopic samples with metallic conductivity should contain parts which are linear in the magnetic field and quadratic in the electric field. These contributions to the current are entirely due to the electron-electron interaction and consequently they are proportional to the electron-electron interaction constant. We also note that both the amplitude and the sign of the current exhibit random oscillations as a function of temperature

Neural Correlates of Adolescent Behavior

Adolescence is a developmental stage between childhood and adulthood associated with numerous brain and behavioral changes. It is also a period of vulnerability, as adolescents tend to take more risks, and various psychiatric problems first typically manifest at this time. Yet little is known about the neuronal basis of these vulnerabilities. Although extracellular electrophysiological recording is a useful technique for measuring the neural activity of awake behaving animals, it had not yet been used to address the neural correlates of adolescent motivated behavior. This dissertation therefore had two primary objectives. The first was to characterize a novel behavioral task suitable for testing adolescent and adult rats. The second was to record the neural activity of brain regions involved in motivated behavior, as adolescents and adults performed it. The behavioral task was a simple instrumental learning paradigm, in which rats associated poking into a hole with the delivery of a food pellet reward. While the learning and performance of this task was similar between the two groups, adolescents persisted in this activity more than adults when reward was withheld. It was determined that this was due to different age-related sensitivities to the presence of certain motivational factors.After characterizing the task, it was performed by adolescent and adult rats that had electrode arrays implanted in their orbitofrontal cortex (OFC), nucleus accumbens (NAc), or dorsal striatum (DS). Neural activity was examined in the context of similar instrumental behavior to determine whether adolescents processed salient events in a fundamentally different way from adults. Several interesting neural processing differences were observed, along with some notable similarities. The greatest phasic activity differences were found in the OFC and DS, particularly during the period immediately before reward. Local field potential oscillations also tended to differ, with particular disparities found in the DS. In contrast, NAc activity tended to look similar between adolescents and adults, with a few exceptions. In addition to demonstrating fundamental age-related neural processing differences during motivated behavior, these findings address existing hypotheses and raise new questions relevant to the neural basis of the increased vulnerabilities of adolescence

Eigen modes for the problem of anomalous light transmission through subwavelength holes

We show that the wide-spread concept of optical eigen modes in lossless waveguide structures, which assumes the separation on propagating and evanescent modes, fails in the case of metal-dielectric structures, including photonic crystals. In addition to these modes, there is a sequence of new eigen-states with complex values of the propagation constant and non-vanishing circulating energy flow. The whole eigen-problem ceases to be hermitian because of changing sign of the optical dielectric constant. The new anomalous modes are shown to be of prime importance for the description of the anomalous light transmission through subwavelength holes.Comment: 5 pages, 4 figure

Optical Turbulence Measurements and Models for Mount John University Observatory

Site measurements were collected at Mount John University Observatory in 2005 and 2007 using a purpose-built scintillation detection and ranging system. $C_n^2(h)$ profiling indicates a weak layer located at 12 - 14 km above sea level and strong low altitude turbulence extending up to 5 km. During calm weather conditions, an additional layer was detected at 6 - 8 km above sea level. $V(h)$ profiling suggests that tropopause layer velocities are nominally 12 - 30 m/s, and near-ground velocities range between 2 -- 20 m/s, dependent on weather. Little seasonal variation was detected in either $C_n^2(h)$ and $V(h)$ profiles. The average coherence length, $r_0$, was found to be $7 \pm 1$ cm for the full profile at a wavelength of 589 nm. The average isoplanatic angle, $\theta_0$, was $1.0 \pm 0.1$ arcsec. The mean turbulence altitude, $\bar{h_0}$, was found to be $2.0\pm0.7$ km above sea level. No average in the Greenwood frequency, $f_G$, could be established due to the gaps present in the \vw\s profiles obtained. A modified Hufnagel-Valley model was developed to describe the $C_n^2(h)$ profiles at Mount John, which estimates $r_0$ at 6 cm and $\theta_0$ at 0.9 arcsec. A series of $V(h)$ models were developed, based on the Greenwood wind model with an additional peak located at low altitudes. Using the $C_n^2(h)$ model and the suggested $V(h)$ model for moderate ground wind speeds, $f_G$ is estimated at 79 Hz.Comment: 14 pages; accepted for publication in PAS

First principles calculations of the Shift Current Bulk Photovoltaic Effect in Ferroelectrics

We calculate the bulk photovoltaic response of the ferroelectrics BaTiO$_3$ and PbTiO$_3$ from first principles by applying "shift current" theory to the electronic structure from density functional theory. The first principles results for BaTiO$_3$ reproduce eperimental photocurrent direction and magnitude as a function of light frequency, as well as the dependence of current on light polarization, demonstrating that shift current is the dominant mechanism of the bulk photovoltaic effect in BaTiO$_3$. Additionally, we analyze the relationship between response and material properties in detail. The photocurrent does not depend simply or strongly on the magnitude of material polarization, as has been previously assumed; instead, electronic states with delocalized, covalent bonding that is highly asymmetric along the current direction are required for strong shift current enhancements. The complexity of the response dependence on both external and material parameters suggests applications not only in solar energy conversion, but to photocatalysis and sensor and switch type devices as well.Comment: First submitted April 2011, submitted PRL July 201