STABILIZATION OF UPLAND RICE PRODUCTION UNDER SHORTENED FALLOW IN WEST AFRICA: RESEARCH PRIORITY SETTING IN A DYNAMIC ENVIRONMENTAL AND ECONOMIC CLIMATE

This paper presents a dynamic model of land resource degradation and shifting rice cultivation in West Africa based upon Boserup and Dvorak. The model indicates the ex ante impact of research strategies to maximize the economic benefits of host plant resistance and land resource management and thereby stabilize yield decline and reduce land degradation.Land Economics/Use, Resource /Energy Economics and Policy,

Effects of Selection Systems on Job Search Decisions

On the basis of Gilliland\u27s (1993) model of selection system fairness, the present study investigated the relationships between selection procedures, perceived selection system fairness, and job search decisions in both hypothetical and actual organizations. We conducted two studies to test the model. In Study 1, we used an experimental method to examine job seekers\u27 perceptions of, and reactions to, five widely used selection procedures. Results suggested that applicants viewed employment interviews and cognitive ability tests as more job related than biographical inventories (biodata), personality tests, and drug tests, and that job relatedness significantly affected fairness perceptions, which in turn affected job search decisions. Study 2 examined the hypothesized relationships between the selection systems and job seekers\u27 pursuit of actual, relevant organizations. Results from both studies offer support for the hypothesized model, suggesting that selection tests have differential effects on perceived selection system validity and fairness, which affect subsequent job search decisions

The geotectonic evolution of the Western Ethiopian shield

The western Ethiopian Shield comprises three lithotectonic units. The Birbir domain, an assemblage of mafic to felsic intrusive and extrusive rocks and mainly volcanogenic sedimentary rocks, is enclosed between the dominantly orthogneissic Baro and Geba domains. The earliest recorded deformation event (D1) resulted in the formation of a subhorizontal gneissosity within the gneissic terranes which was synchronous with an early upper amphibolite-facies metamorphic peak (M1) at 800–770 Ma which locally caused partial melting. All terrains were subsequently deformed in the D2 event which was the result of severe E-W crustal shortening. An anticlockwise P-T-t path is implied. Subsequent D3 deformation was concentrated within mylonitised domain boundaries which record major transcurrent movement. These structures were reactivated and suffered fluid incursion resulting in isotopic reequilibration at 635–580 Ma. A second metamorphic event, M2, related to crustal thickening and consequent granite genesis, occurred after the cessation of D3 shearing. Bulk chemical analyses show that the metamorphosed plutonic and volcanic rocks of the Birbir domain are predominantly calc-alkaline and similar to those generated by subduction in modern magmatic arcs. They belong in part to the low-K series, suggesting an oceanic environment. The evolution of the region can be explained in terms of the melting of a subducting slab, intrusion, metamorphism and the formation of an oceanic island arc complex. Continued plate convergence caused severe east-west shortening and basin closure. Further attenuation gave rise to transcurrent shearing, fluid influx, a second thermal event and accretion of microcontinents. Key words/phrases: Accretion, cratonisation, isotope systems, subduction, transcurrent movement SINET: Ethiopian Journal of Science Vol.25(2) 2002: 227-25

Employee Age as a Moderator of the Relationship Between Ambition and Work Role Affect

Past research has demonstrated a negative relationship between ambition, or the desire to get ahead, and job satisfaction. In the present paper, age was hypothesized to moderate the relationship between ambition and job satisfaction such that the relationship between ambition and satisfaction is more negative for older employees than for younger employees. Three studies, with three criterion variables (promotion satisfaction, extrinsic job satisfaction, overall job satisfaction), were used to test the hypothesis. Results indicated support for the hypothesized interaction. The discussion focuses on the implications of the results for organizational and individual career management strategies

T-maze learning in weanling lambs

A major advantage of sheep models in experimental studies of neurodevelopmental disorders (e.g., with prenatal neurotoxicant exposure) is that the equivalent of all three trimesters of human brain development occurs in sheep entirely in utero. However, studies of learning and memory in sheep are limited. The goal of this study was to extend the analysis of spatial learning and memory in adolescent sheep using several traditional T-maze tasks. Both 9- and 14-week-old lambs acquired a delayed non-matching to place task, but the older lambs learned the task significantly faster. In contrast, acquisition of a matching to place task was significantly more difficult. Lambs, like rodents, appear to have a predisposition toward learning “win-shift” spatial problems in a T-maze under appetitive motivation. Lambs also rapidly acquired a position habit and showed typical reversal learning curves. These findings support the use of T-maze tasks to assess behavioral outcomes in various sheep models

Cluster Mass Inference Method via Random Field Theory

Cluster extent and voxel intensity are two widely used statistics in neuroimaging inference. Cluster extent is sensitive to spatially extended signals while voxel intensity is better for intense but focal signals. In order to leverage strength from both statistics, several nonparametric permutation methods have been proposed to combine the two methods. Simulation studies have shown that of the different cluster permutation methods, the cluster mass statistic is generally the best. However, to date, there is no parametric cluster mass inference available. In this paper, we propose a cluster mass inference method based on random field theory (RFT). We develop this method for Gaussian images, extend it to Student’s t-statistic images and investigate its statistical properties via simulation studies and real data. Simulation results show that the method is valid under the null hypothesis and demonstrate that it can be more powerful than the cluster extent inference method. Further, analyses with a single-subject and a group fMRI dataset demonstrate better power than traditional cluster size inference, and good accuracy relative to a gold-standard permutation test

CONCENTRATION ISSUES IN THE U.S. BEEF SUBSECTOR

Industrial Organization, Livestock Production/Industries,

Using Peer and Team Performance Assessments as Learning Tools on Collaborative Student Projects

Leaving the team experience unevaluated during collaborative student projects leaves the educational benefit of student peer feedback unrealized. Performance feedback between student teams and among individual team members adds a valuable educational component during applied learning projects. Faculty in the Aviation Technology program at Purdue University piloted the use of team and individual student peer evaluation tools as performance feedback and learning mechanisms in two maintenance technology courses engaged in collaborative team projects. Use of peer performance reviews among the students during team-based projects resulted in willingness to engage in proactive problem solving and communication among students while individual scores in these areas increased