On the Complete Information First--Price Auction and its Intuitive Solution

Despite the popularity of auction theoretical thinking, it appears that no one has presented an elementary equilibrium analysis of the complete information first-price sealed-bid auction mechanism when the bidding space has a finite grid. This paper aims to remedy that omission. We show that there always exists a "high price equilibrium" which can be considered "the intuitive solution" (an agent with the highest valuation wins the auction bidding at the second-highest valuation). Although there might be other "low price equilibria", we also show that when there are two bidders "the intuitive solution" is the unique limiting equilibrium when the grid size goes to zero and ties are randomly broken.First-price auctions; undominated Nash equilibria.

On Integration Policies and Schooling

This paper proposes a reform for school allocation procedures in order to help integration policies reach their objective. For this purpose, we suggest the use of a natural two-step mechanism. The (stable) first step is introduced as an adaptation of the deferred-acceptance algorithm designed by Gale and Shapley (1962), when students are divided into two groups. The (efficient) second step captures the idea of exchanging places inherent to Gale's Top Trading Cycle. This latter step could be useful for Municipal School Boards when implementing some integration policies.Integration Policy; School Allocation; Affirmative Action

Re-Reforming the Bostonian System: A Novel Approach to the Schooling Problem

This paper proposes the notion of E-stability to conciliate Pareto efficiency and fairness. We propose the use of a centralized procedure, the Exchanging Places Mechanism. It endows students a position according with the Gale and Shapley students optimal stable matching as tentative allocation and allows the student to trade their positions. We show that the final allocation is E-stable, i.e. efficient, fair and immune to any justifiable objection that students can formulate.School allocation problem, Pareto efficient matching

On the trade-off between supplier diversity and cost-effective procurement

The COVID-19 pandemic has highlighted the need to rely on a diverse pool of suppliers, besides achieving cost effectiveness. Common wisdom, however, holds that these two aims are in conflict. We explore a model of dual sourcing and propose complementing a share auction with affirmative action to create an endogenous set-aside for a high-cost supplier. In our model more intensive affirmative action strengthens the targeted provider. This has the potential to level the playing field, inducing more competitive procurement overall. Our main result provides a condition under which the endogenous set-aside not only guarantees a very substantial share for the high-cost supplier, but also reduces the buyer's provision cost compared to a standard auction. We also illustrate how our approach can help reducing the severity and likelihood of health product shortages, such as those occurred during the COVID-19 outbreak.This work is partially supported by the Spanish Ministerio de Economía y Competitividad, project ECO2016-77200-P, and Ministerio de Ciencia e Innovación, project PID2022-138111NB-I00

Equalizing solutions for bankruptcy problems revisited

When solving bankruptcy problems through equalizing solutions, agents with small claims prefer to distribute the estate according to the Constrained Equal Awards solution, while the adoption of the Constrained Equal Losses solution is preferred by agents with high claims. Therefore, the determination of which is the central claimant, as a reference to distinguish the agents with a high claim from those with a low claim, is a relevant question when designing hybrid solutions, or new methods to distribute the available estate in a bankruptcy problem. We explore the relationship between the equal awards parameter λ and the equal losses parameter μ that characterize the two solutions. We show that the central claimant is fully determined by these parameters. In addition, we explore how to compute these parameters and present optimization problems that provide the Constrained Equal Awards and the Constrained Equal Losses solutions.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

#42 - Deterrence of Ants by Chemical Compounds from Six Southeastern Plants

Ant interactions with plants are diverse; therefore, one of the most important aspects of ant-plant interactions is the exposure of ants to plant compounds. These compounds can serve as cues to either enhance or deter recruitment of ants to food. The purpose of this experiment is to measure the recruitment of ants to extracts that were made from six different southeastern native plants, all of which display a wide range of chemical diversity. Seven different extracts were mixed using a sugar solution. Six of the extracts had the dried leaf material of the plants Solidago altissimus, Verbesina virginica, Callicarpa americana, Pycnanthemum muticum, Catalpa speciosa, and Cercis canadensis dissolved in the solution while the seventh was a control. The experiment was conducted for 15 minutes per solution and the number of ants was counted at each one-minute interval. Overall, the ants were attracted more towards the control extract. During the first four minutes, the mean number of ants attracted to the extracts containing Verbesina virginica and Catalpa speciosa were high, however, this number declined over time. No significant signs of recruitment were shown by the other four extracts. Collectively, the data suggests that ants were more attracted to the sugar control. This conclusion presents an application that the chemistry of plant compounds may have a strong significance to ant deterrence

Beyond the Spanish MIR with Consent: (Hidden) Cooperation and Coordination in Matching

Sequential mechanisms to solve matching problems are useful to promote (hidden) cooperation between agents. Taking as a starting point the MIRC mechanism, employed in Spain to match medical students and residency programs in privately owned hospitals, we find that: (1) In the current system, where the number of students that each program might enroll is limited, the unique equilibrium allocation can be unstable. (2) When the above limit is not (formally) imposed, instability is not expected to occur. Nevertheless, the multiplicity of equilibria shows that coordination failure might emerge, generating a social welfare loss. (3) When the role of students and hospitals is reversed in the MIRC mechanism, (hidden) cooperation is guaranteed. Moreover, coordination failure disappears.This work is partially supported by the Spanish Ministerio de Economía y Competitividad, under projects ECO2013-43119-P and ECO2016-77200-P

Entrevista con Philippe Garrel

Alcalde, JÁ. (2001). Entrevista con Philippe Garrel. La madriguera. (35):56-61. http://hdl.handle.net/10251/41933.Importación Masiva56613

Multiple anti-predator mechanisms in the red-spotted Argentina Frog (Amphibia: Hylidae)

Anurans employ a wide variety of anti-predator mechanisms to defend themselves. In casque-headed hylids, defence is thought to be a complex combination of several anti-predator mechanisms. However, the defence traits of only a few species are known; some hypotheses have yet to be addressed, whereas others, already tested in some species, need to be tested in additional taxa. The anti-predator mechanism of the casque-headed frog, Argenteohyla siemersi, is described here. It is a complex mechanism consisting of (1) behavioural and ecological traits, including secretive and semi-phragmotic habits and posture; (2) morphological features, including cryptic and aposematic colourations, a skull covered with bony dermal spines and protuberances that are associated with two types of granular venom glands; and (3) physiological and chemical traits, such as a highly lethal skin secretion. Our results are compared with those of previous studies of defence mechanisms in casque-headed frogs in an effort to understand the mechanisms and evaluate their potential phylogenetic signal in this group of anurans.Fil: Cajade, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; ArgentinaFil: Hermida, Gladys Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Piñeiro, Jose Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; ArgentinaFil: Regueira, Eleonora. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Alcalde, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Fusco, Luciano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Bioquímica; ArgentinaFil: Marangoni, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; Argentin

Competition for procurement shares

We propose a new procurement procedure which allocates shares of the total amount to be procured depending on the bids of suppliers. Among the properties of the mechanism are: (i) Bidders have an incentive to participate in the procurement procedure, as equilibrium payoffs are strictly positive. (ii) The mechanism allows to vary the extent to which affirmative action objectives, like promoting local industries, are pursued. (iii) Surprisingly, even accomplishing affirmative action goals, procurement expenditures might be lower than under a classical auction format