Collusion under Yardstick Competition: An Experimental Study

The effectiveness of relative performance evaluation schemes, such as yardstick competition, can be undermined by collusion.The degree to which the regulated agents manage to collude will be affected by the particulars of the scheme.We hypothesize that in a repeated game setting schemes will be more prone to collusion the smaller are the rents to the agents in case they behave non-cooperatively.We illustrate the relevance of this hypothesis by means of an economic experiment in which we compare the efficiency of two performance evaluation schemes.performance evaluation;competition;efficiency;games;collusion;yardstick

Amnesia and the DRM Paradigm: How Encoding Factors (Do Not) Affect Lure Recognition

In the DRM paradigm, participants are presented with, and their memory is tested for, lists of words that are associatively related to a non-presented lure word. Recent studies have revealed that amnesic patients show heightened immediate, but diminished delayed false recognition of such related lure words as compared to healthy controls. These findings may reflect deficient encoding, retrieval, or both. In two experiments, the importance of encoding factors was evaluated by investigating whether story contexts would increase delayed lure recognition, and whether personally-relevant content would decrease immediate lure recognition in Korsakoff patients. With delayed testing, patients' lure recognition was consistently lower than controls'. With immediate testing, lure recognition was less frequent for personally-relevant than for neutral materials. However, as opposed to controls, Korsakoff patients did not show a difference in source memory, but merely a change in response bias. Results point to the conclusion that deficient explicit recollection is the main factor determining the difference in false recognition between amnesic patients and controls

Distribution and contamination status of heavy metals in estuarine sediments near Cua Ong Harbour, Ha Long Bay, Vietnam

The distribution, controlling geochemical factors and contamination status of heavy metals in estuarine sediments near Cua Ong Habor, Ha Long Bay (Vietnam) were investigated. 36 surface sediment samples were collected and analyzed for major elements (Al, Ca, Fe, K, Mg, S), heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn), organic matter, loss on ignition (LOI), grain size composition and pH. Spatial distribution patterns of heavy metals as well as their controlling factors were elucidated based on geochemical mapping and statistical methods such as the Pearson ProductMoment linear correlation and Factor Analysis. The results illustrated that the distribution patterns of As, Cd, Cr, Cu, Ni, Pb and Zn are mainly controlled by organic matter and clay minerals and determined by the distribution of the finegrained fraction (F < 63 µm) in the sediments. In contrast, Fe and Mn compounds seem to exert some control on the distribution of Co. Carbonates partly control the distribution of Mn, but are not important with respect to the other studied heavy metals. The contamination status by heavy metals was assessed based on comparison with Canadian, Wisconsin- United States and Flemish numerical Sediment Quality Guidelines, and calculation of Geo-accumulation Index (Igeo) and Enrichment Factor (EF). The results indicated that natural processes such as weathering and erosion of bedrock are the main supply sources of heavy metals in sediments near Cua Ong Harbor. Among the studied heavy metals, only As is of concern whereas Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn seem to reflect their background concentrations in sediments of Ha Long Bay

Collusion under yardstick competition:An experimental study

The effectiveness of relative performance evaluation schemes, such as yardstick competition, can be undermined by collusion.The degree to which the regulated agents manage to collude will be affected by the particulars of the scheme.We hypothesize that in a repeated game setting schemes will be more prone to collusion the smaller are the rents to the agents in case they behave non-cooperatively.We illustrate the relevance of this hypothesis by means of an economic experiment in which we compare the efficiency of two performance evaluation schemes

Evolutionary history and identification of conservation units in the giant otter, Pteronura brasiliensis.

The giant otter, Pteronura brasiliensis, occupies a range including the major drainage basins of South America, yet the degree of structure that exists within and among populations inhabiting these drainages is unknown. We sequenced portions of the mitochondrial DNA (mtDNA) cytochrome b (612 bp) and control region (383 bp) genes in order to determine patterns of genetic variation within the species. We found high levels of mtDNA haplotype diversity (h = 0.93 overall) and support for subdivision into four distinct groups of populations, representing important centers of genetic diversity and useful units for prioritizing conservation within the giant otter. We tested these results against the predictions of three hypotheses of Amazonian diversification (Pleistocene Refugia, Paleogeography, and Hydrogeology). While the phylogeographic pattern conformed to the predictions of the Refugia Hypothesis, molecular dating using a relaxed clock revealed the phylogroups diverged from one another between 1.69 and 0.84 Ma, ruling out the influence of Late Pleistocene glacial refugia. However, the role of Plio-Pleistocene climate change could not be rejected. While the molecular dating also makes the influence of geological arches according to the Paleogeography Hypothesis extremely unlikely, the recent Pliocene formation of the Fitzcarrald Arch and its effect of subsequently altering drainage pattern could not be rejected. The data presented here support the interactions of both climatic and hydrological changes resulting from geological activity in the Plio-Pleistocene, in shaping the phylogeographic structure of the giant otter