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Inverse Function (inverse + function)
Selected AbstractsAccurate motion-produced distance and direction under systematically distorted perceptionJAPANESE PSYCHOLOGICAL RESEARCH, Issue 3 2005NAOFUMI FUJITA Abstract:, We report the visually directed actions of soccer players. After perceiving the location of a target on their left side at the starting point and traveling toward the ball without seeing the target, the players could kick the ball accurately (Experiment 2). In contrast, if they were verbally asked the direction of the target in a similar situation, the perceived direction was systematically distorted (Experiment 3). Our major concern in explaining the distorted perception was whether the egocentric distance before locomotion was perceived accurately or not, and whether the updating of the target location during locomotion was accurate or not. Combining these two possibilities, there should be four hypotheses, each of which assumes either: (1) accurate egocentric distance and accurate updating, (2) inaccurate egocentric distance and accurate updating, (3) accurate egocentric distance and inaccurate updating, or (4) inaccurate egocentric distance and inaccurate updating. Based on these hypotheses, we conducted four simulations, which revealed that the combination of the perception of the accurate egocentric distance and the distorted updating that substituted the constant function for the sine function produced not only a good r2, but also three kinds of interactions obtained in Experiment 3. Why did the players, based on their distorted perception, perform accurately? We would like to suggest that through perceptual learning they might acquire a perceptual-motor relation as the inverse function of the physical-perceptual relation. [source] Effects of food limitation and emigration on self-thinning in experimental minnow cohortsJOURNAL OF ANIMAL ECOLOGY, Issue 6 2000J. B. Dunham Summary 1.,The theory of food-regulated self-thinning (FST) for mobile animals predicts population density (N) to be an inverse function of mean body mass (W) scaled to an exponent (b), such that N = k W,b, where k is a constant. FST also predicts energy requirements (or energy flow) to remain constant over time (termed energetic equivalence) as losses to cohorts (e.g. emigration and mortality) are balanced by increased growth of surviving individuals. 2.,To test these predictions, we analysed the dynamics of six experimental minnow cohorts. Replicate populations of fish were held under identical conditions with a constant and limited supply of food over a 126-day period. Half of the cohorts were open to emigration, and half were closed so that fish could only be lost through starvation mortality. 3.,Patterns of self-thinning indicated non-linear changes in population density and energy flow in relation to changes in mean body mass and time, respectively. Non-linear patterns of self-thinning were probably due to a delayed growth response to changes in population density effected through mortality and/or emigration. Contrary to results of similar experiments on other fish, emigration did not have a significant influence on the pattern of self-thinning. 4.,These results may be attributed to trophic interactions within cohorts and the importance of social behaviour to cohort dynamics. Both population density and energy flow in our experimental populations appeared to cycle, with episodes of starvation and mortality alternating with food recovery and weight gain, as predicted by recent models of stepwise die-off and stunted growth in animal cohorts. 5.,Most of the support for FST in mobile animals comes from observational data on mean body mass and population density. Potentially important mechanisms, including the manner in which individuals are lost or retained in populations, are usually not investigated directly. Such tests of FST can only provide equivocal support. Detailed observational study and controlled experiments are needed to understand casual mechanisms. [source] Building a Strong Foothold in an Emerging Market: A Link Between Resource Commitment and Environment Conditions*JOURNAL OF MANAGEMENT STUDIES, Issue 5 2004Yadong Luo ABSTRACT This study examines how MNEs align resource commitment with environmental conditions (challenges and opportunities) when they invest in a foreign emerging market. MNEs often face a dilemma in allocating resources to this environment: without this commitment, they cannot build a strong competitive foothold; yet with over-commitment, there is excessive economic exposure. Our analysis of MNEs in a major emerging market suggests that resource commitment is an inverse function of market uncertainty and this inverse link is stronger for less strategically proactive MNEs. Resource commitment is also an increasing function of market opportunities and this function is stronger for firms emphasizing demand-side (as opposed to cost-side) gains. In addition, in a highly volatile industry, resource commitment is negatively associated with cultural distance, but in a relatively stable industry, it is positively associated with cultural distance. And finally, as foreign subsidiaries become older, the influence of cultural distance on resource commitment is weakened. [source] Pore-size effects on activated-carbon capacities for volatile organic compound adsorptionAICHE JOURNAL, Issue 8 2002Mei-Chiung Huang Gas-phase adsorption of acetone and n-hexane by activated carbons with different pore structures was investigated. The carbons were prepared from a bituminous coal with KOH activation. Increasing the activation temperature increased both the porosity and pore size. The equilibrium adsorption capacity for the organic compounds increased with the carbon porosity, but not proportionally. The percentage of pore volume utilized showed a decreasing trend with the porosity development for acetone adsorption, while an increasing trend was observed for n-hexane. By incorporating pore size distribution with the Dubinin-Radushkevich equation using an inverse proportionality between the micropore size and adsorption energy, the isotherms for adsorption onto different carbons can be well predicted. Simulations indicated that the adsorption energy, which is an inverse function of the micropore size, determines the adsorption capacity. Different effects of porosity development were observed for different adsorbates. [source] FERRIC CHELATE REDUCTASE ACTIVITY AS AFFECTED BY THE IRON-LIMITED GROWTH RATE IN FOUR SPECIES OF UNICELLULAR GREEN ALGAE (CHLOROPHYTA)1JOURNAL OF PHYCOLOGY, Issue 3 2002Harold G. Weger Four species of green algae (Chlorella kessleri Fott et Nováková, Chlorococcum macrostigmatum Starr, Haematococcus lacustris[Girod-Chantrans] Rostaf., Stichococcus bacillaris Näg.) were grown in iron-limited chemostats and under phosphate limitation and iron (nutrient) sufficiency. For all four species, steady-state culture density declined with decreasing degree of iron limitation (increasing iron-limited growth rate), whereas chl per cell or biovolume increased. Plasma membrane ferric chelate reductase activity was enhanced by iron limitation in all species and suppressed by phosphate limitation and iron sufficiency. These results confirm previous work that C. kessleri uses a reductive mechanism of iron acquisition and also suggest that the other three species use the same mechanism. Although imposition of iron limitation led to enhanced activities of ferric chelate reductase in all species, the relationship between ferric chelate reductase activity and degree of iron limitation varied. Ferric chelate reductase activity in C. macrostigmatum and S. bacillaris was an inverse function of the degree of iron limitation, with the most rapidly growing iron-limited cells exhibiting the highest ferric chelate reductase activity. In contrast, ferric chelate reductase activity was only weakly affected by the degree of iron limitation in C. kessleri and H. lacustris. Calculation of ferric reductase activity per unit chl allowed a clear differentiation between iron-limited and iron-sufficient cells. The possible extension of the ferric chelate reductase assay to investigate the absence or presence of iron limitation in natural waters may be feasible, but it is unlikely that the assay could be used to estimate the degree of iron limitation. [source] | ||||||||||