Fried (in Public Choice, this issue, 2013) claims that Quesada (in Public Choice 130:395-400, 2007) is wrong in showing that the dictator in a dictatorial social welfare function does not necessarily enjoy absolute decision power. This reply revisits, and illustrates by means of an example, the framework where Quesada's result is obtained. It is argued that Fried's counterfactual analysis conducted to invalidate Quesada's conclusion relies on untenable presumptions: (i) that the rules to identify the values of a social welfare function say something about how these values must have been obtained; and (ii) that counterfactual analysis can be conducted in an environment where causes and effects cannot be unequivocally established. Adapted from the source document.
For the case of strict preferences, a measure of a voter's average power in a dictatorial social welfare function is defined making the dictator never have more average power than three voters and, as the number of voters grows, making the dictator's average power converge to the average power of two voters. This result suggests, as those in Tangian (2004), that dictatorial social welfare functions might not be as undesirable aggregation rules as traditionally held. Adapted from the source document.
A voting function is a rule that determines the outcome of an election: taking the voters' votes as input, a voting function selects the winning candidate from the set of candidates receiving some vote. A voting function is immune to vote selling when, given that neither voter i nor voter j votes for the winning candidate, a change ceteris paribus in i's vote cannot make the candidate for which j votes the winner. It is shown that voting functions immune to vote selling have either a dictator (a voter who always determines the winning candidate) or a dictated candidate (a candidate who becomes the winner by just receiving some vote). 1 Appendix, 6 References. [Copyright 2005 Elsevier B.V.]
Inquiry pedagogies provide opportunities to meet learning outcomes linked to developing scientific literacy. Within a European project intended at promoting Inquiry Based Learning (IBL), this paper presents quantitative and qualitative data about teachers' views of IBL and its enactment in England and Spain. Results show that teachers in both countries hold positive views based on benefits to students and science learning and perceive important systemic and personal barriers to the successful implementation, even after decades of political efforts. Teachers express frustration with the lack of time, teaching resources, classroom management and the demands of curriculum delivery, assessment and accountability. There is an emphasis on hands-on activities and students' motivation but no stress on cognitive and epistemic aspects, showing views not well aligned with current understanding of the type of inquiry that best support learning. Implications for research and practice suggest that there is still a need to expand knowledge about how to support teachers in making the most of this pedagogy.
AbstractCylindrospermopsin (CYN) is a potent cyanobacterial toxin found in freshwaters worldwide. In this work, the feasibility of the photo-Fenton process under neutral pH using light emitting diodes as irradiation source for the removal of this hazardous cyanotoxin from freshwater was investigated. The impact of the kind of iron chelating agent (ethylenediamine-N, N′-disuccinic acid vs. ethylenedinitrilotetraacetic acid) as well as the effect of the main operating conditions viz. H2O2 dose, Fe(III) load, initial CYN concentration, and Fe(III):EDDS molar ratio on the performance of the process was systematically evaluated. EDDS was selected as the most appropriate iron chelating agent considering the kinetics of the process and the environmental impact (Vibrio fischeri and Artemia salina). Under optimized conditions ([H2O2] = 30 mg L−1; [Fe(III)] = 5 mg L−1; Fe(III):ligand = 1:0.5 (molar ratio)), complete removal of CYN was achieved in 15-min reaction time. Furthermore, the catalytic system showed to be effective in real water matrices (river and reservoir waters) spiked with CYN. Although the presence of inorganic ions (mainly HCO3−/CO32−) and dissolved organic carbon decreased the oxidation rate of CYN due to scavenging reactions and iron coordination, respectively, complete elimination of the cyanotoxin was achieved in all cases. The fate of EDDS along the process was also evaluated to demonstrate that the catalytic system investigated, apart from its effectiveness, warrants the complete absence of residues after reaction. Therefore, the proposed system constitutes a promising method for cyanotoxin treatment either as a drinking water treatment step in conventional plants or as a potential remediation strategy in the natural environment.
