Preference Reversals in Personnel Selection

Preference reversals, in which one alternative is preferred in a choice task while another alternative is preferred in a judgment task, may occur in personnel selection. If so, the candidate who is assigned the highest predictor score may not be the candidate the selector would have chosen. Previous research does not clearly indicate the rate of preference reversals that are likely to occur in personnel selection. A simulated selection task carried out by 157 managers revealed near-zero levels of preference reversals. Implications for decision theory and personnel selection research are discussed

Alien Registration- Boudreau, Dolph P. (Auburn, Androscoggin County)

https://digitalmaine.com/alien_docs/30952/thumbnail.jp

On the equivalence of nonlocal and radial-diffusion models for porewater irrigation

Aller (1977, 1978, 1980) and Aller and Yingst (1978) have demonstrated that the presence of well-irrigated worm-tubes and other animal burrows in sediments can significantly alter the rate of exchange of solutes between porewater and the overlying waters. Specifically, the burrows modify the geometry of the porewater system such that solutes can diffuse toward or away from either the sediment-water interface or the burrow. The burrow constitutes an additional boundary source or sink..

A provisional diagenetic model for pH in anoxic porewaters: Application to the FOAM Site

This paper presents a diffusion-advection-reaction model for the pH of anoxic porewaters in nonirrigated sediments. Because of the couplings demanded by the organic-matter decay reaction, various acid-base interconversions, dissolved-iron generation, and CaCO3 and FeS precipitation, the model does not consider H+ alone, but deals simultaneously with 17 dissolved species. The complex and largely unknown kinetics of some of the processes affecting these species have been approximated by simple ad hoc formulations. For this reason, the model must be considered provisional. We have also made extensive use of the local (partial) equilibrium assumption to circumvent the computational problems generated by rapid association/dissociation reactions. The FOAM Site data are used as a vehicle to display the capabilities of this model. Assuming local equilibrium with FeS, the predicted pH profile is most sensitive to the reaction that liberates iron from the solid phase. The FOAM pH does not conform to a profile expected for anyone iron-source mineral, but appears to reflect a composite source. Based on currently available data, this source might include magnetite and silicate minerals, but is unlikely to involve ferric oxides and hydroxides. The pH of FOAM porewaters is much less sensitive to the precipitation of FeS and CaCO3 than would be suggested by past closed-system models. The overall pH stability of anoxic porewaters is attributable to the fact that the dissolved products of organic-matter decomposition are added in such a way as to form a self-buffering mixture

An experimental and modeling study of pH and related solutes in an irrigated anoxic coastal sediment

Macrofaunal irrigation is an important process in nearshore sediments, facilitating greater exchange between sediments and seawater and imparting significant lateral heterogeneity to the porewater profiles of many constituents. Like many macrofaunal activities, irrigation is a transient behavior, i.e. tubes and burrows are flushed periodically, at frequencies that generally are species-specific. As a result, transient concentrations within the dwelling arise, potentially impacting gradients, fluxes and reaction rates in the vicinity of the dwelling. We investigated the impact of periodic burrow irrigation on the distribution of several diagenetically important porewater constituents. Laboratory experiments evaluated irrigation periodicity using artificially irrigated tubes embedded in nearshore organic-rich sediments, and microdistributions of oxygen and pH in laboratory experiments were measured with microelectrodes. To help interpret our results, we also constructed a simplified time and space-dependent transport-reaction model for oxygen, pH and sulfide in irrigated sediments. Laboratory results show substantial differences in the pH field of sediments surrounding an irrigated tube as a function of irrigation frequency. Higher pH values, indicative of an overlying water signature, were observed in the vicinity of the tube wall with increasing duration of irrigation. Conversely, oxygen concentrations did not vary significantly with the amount of irrigation, most likely a result of extremely high sediment oxygen demand. Model results are consistent with laboratory findings in predicting differences in the measured variables as a function of irrigation frequency. However, the nature and extent of the model-predicted differences are often at variance with the experimental data. Overall, experimental and modeling results both suggest irrigation periodicity can substantially influence porewater distributions and diagenetic processes in sediments. Future studies should examine the influence of irrigation periodicity on the types and rates of reactions, and the attendant biological features, in the environment encompassing the tube or burrow wall

A modelling study of discontinuous biological irrigation

Irrigation of infaunal dwellings can lead to significant alteration of solute distributions in sediments. As a result, sediment-seawater fluxes of nutrients and dissolved carbon are greatly enhanced, and the biology of benthic communities is affected. The most realistic mathematical representation of irrigation and its effect on sediment geochemistry is Aller\u27s (1980) cylinder model. One critical assumption of this model is that burrows are irrigated continually, and that burrow water solute concentrations are identical to overlying water concentrations at all times. However, the vast majority of infaunal tube- and burrow-dwelling organisms irrigate periodically, i.e. in an on/off cycle. During periodic irrigation, the solute concentration at the tube wall may vary between the limits imposed by the flux from the porewater and the concentration in the overlying water. We introduce modifications to the cylinder model which allow for periodic irrigation. We assess how periodic irrigation affects solute profiles and fluxes of two chemical constituents, silica and ammonium, for different population densities (distance between burrows) and organism sizes (burrow radii). Silica and ammonium follow first and zeroth order reaction kinetics, respectively, and illustrate the behavior of two general reaction classes. Model results show that the effects of periodic irrigation vary with the class of reaction considered. For silica, radially-averaged profiles during discontinuous irrigation varied less than 15% from those with continuous irrigation for nearly all burrow sizes, burrow distances and reaction rate constants considered. However, we observed large temporal changes (as much as a factor of 6) in the areally-averaged silica flux over the irrigation cycle. Despite this time-dependence, the time-averaged silica flux was similar to that calculated for the continuous case. For ammonia, radially-averaged solute profiles were extremely sensitive to the duration of irrigation. In this case, the differences between discontinuous and continuous irrigation were greatest when the duration of irrigation was short (e.g. 5 min), and when the inter-burrow distance was small. As with silica, there was a strong time-dependence in areally-averaged ammonia flux when irrigation was periodic. However, the time-averaged ammonia flux is identical to the flux calculated for continuous irrigation. Our results suggest that irrigation behavior can affect the local burrow environment and this imposes a time dependence on solute fluxes

A Data Structure for Spatio-Temporal Databases

The advantages and applications of spatial mechanisms are well documented; however, there are very few being designed. The principal hinderance to the design of spatial mechanisms is the great difficulty involved in specifying spatial problems and in interpreting spatial solutions. Similarly, the development of spatial codes to implement these techniques is held back by the lack of means to easily visualize and verify solutions, particularly in the realm of relational databases. If spatial mechanisms are to be successful, the designer must be able to synthesize, analyse and evaluate, as well as load and extract information, using a single code representing a spatial structure. This entails the implementation of spatial relationships involving spatial data structures. It is with this in mind that the Canadian Hydrographic Service database group embarked on the development of a new type of spatial database structure based on the quadtree concept

Ongoing transients in carbonate compensation

Uptake of anthropogenic CO2 is acidifying the oceans. Over the next 2000 years, this will modify the dissolution and preservation of sedimentary carbonate. By coupling new formulas for the positions of the calcite saturation horizon, zsat, the compensation depth, zcc, and the snowline, zsnow, to a biogeochemical model of the oceanic carbonate system, we evaluate how these horizons will change with ongoing ocean acidification. Our model is an extended Havardton-Bear-type box model, which includes novel kinetic descriptions for carbonate dissolution above, between, and below these critical depths. In the preindustrial ocean, zsat and zcc are at 3939 and 4750 m, respectively. When forced with the IS92a CO2 emission scenario, the model forecasts (1) that zsat will rise rapidly (“runaway” conditions) so that all deep water becomes undersaturated, (2) that zcc will also rise and over 1000 years will pass before it will be stabilized by the dissolution of previously deposited CaCO3, and (3) that zsnow will respond slowly to acidification, rising by ∼1150 m during a 2000 year timeframe. A further simplified model that equates the compensation and saturation depths produces quantitatively different results. Finally, additional feedbacks due to acidification on calcification and increased atmospheric CO2 on organic matter productivity strongly affect the positions of the compensation horizons and their dynamics.

Simulated fiddler-crab sediment mixing

Using a lattice-automaton model, we simulate the effects of fiddler crabs on the distribution of excess 210Pb in marsh sediments. Three previously-identified modes of bioturbation are investigated: (1) removal-and-fill, where material is excavated to the sediment-water interface and burrows, when abandoned, are subsequently filled by surface material, (2) removal-and-collapse, where the infilling occurs by collapse of the burrow walls, and (3) partial-compaction-and-collapse, where part of the excavated sediment is packed into the burrow wall and abandoned burrows subsequently collapse. These various mixing modes lead to somewhat different laterally-integrated 210Pbex profiles, which are also influenced by burrowing frequency, burrow dimensions, fraction of surface material replaced by new sediment (regeneration), and the fraction of material compacted during burial.Using parameters from a previous study in a South Carolina marsh, we find that data from low-marsh sites are best predicted by the partial-compaction-and-collapse process; this is consistent with the observation that burrow casts indicate far more material is excavated than is deposited as pellets at the sediment-water interface. The profile from the high-marsh site is best simulated by removal-and-fill mixing, with 50% regeneration of material at the sediment-water interface; this is consistent with less frequent flooding at this site.We have also calculated the exchange function for each of these mixing modes and show that they are highly asymmetric, indicating that the mixing is not diffusive. Only in the case of partialcompaction-and-collapse does the exchange function approach a diffusive form when the excavation rate decreases, i.e., the probability of compaction increases

Do girls have all the fun? Anxiety and enjoyment in the foreign language classroom

The present study focuses on gender differences in Foreign Language Enjoyment (FLE) and Foreign Language Classroom Anxiety (FLCA) among 1736 FL learners (1287 females, 449 males) from around the world. We used 21 items, rated on a Likert scale, reflecting various aspects of FLE (Dewaele & MacIntyre, 2014), and 8 items extracted from the FLCAS (Horwitz et al., 1986). An open question on FLE also provided us with narrative data. Previous research on the database, relying on an average measure of FLE and FLCA (Dewaele & MacIntyre, 2014) revealed significant gender differences. The present study looks at gender differences in FLE and FLCA at item level. Independent t-tests revealed that female participants reported having significantly more fun in the FL class, where they felt that they were learning interesting things, and they were prouder than male peers of their FL performance. However, female participants also experienced significantly more (mild) FLCA: they worried significantly more than male peers about their mistakes and were less confident in using the FL. Our female participants thus reported experiencing both more positive and more mild negative emotions in the FL classroom. We argue that this heightened emotionality benefits the acquisition and use of the FL