Enjoying cooperative games: The R package GameTheory

This paper focuses on cooperative games with transferable utility. We propose the computation of two solutions, the Shapley value for n agents and the nucleolus with a maximum of four agents. The current approach is also focused on conflicting claims problems, a particular case of coalitional games. We provide the computation of the most well-known and used claims solutions: the proportional, the constrained equal awards, the constrained equal losses, the Talmud and the random arrival rules. Keywords: Cooperative game, Shapley value, nucleolus, claims problem, claims rule, bankruptcy.

Microfinance and credit rationing in Ghana: Does the microfinance type matter?

This study sets out to examine the extent to which access to credit and credit rationing are influenced by the microfinance type based on the major factors determining micro, small and medium enterprises’ access to credit from microfinance institutions in the era of financial liberalization. The data for the study were gleaned from the microfinance institutions’ credit and loan records consisting of the various pieces of information provided by the borrowers in the application process. Our results are puzzling and show that credit rationing is not influenced by the microfinance types but by the individual microfinance institutions. Keywords: Microfinance, Ghana, Credit Rationing. JEL codes: G21

Do Schools Discriminate Against Homosexual Parents? Evidence from an Internet Field Experiment

The recognition of homosexual rights is a controversial issue in many countries. Spain was the third country in the world (after Netherlands and Belgium) to introduce a law recognizing homosexual marriage and adoption of children. In this paper, we examine for the first time whether schools are more hesitant to give feedback to homosexual parents during children's pre-registration period in Spain. In order to do that, we designed an internet field experiment to be conducted in schools. We created three types of fictitious couples; one heterosexual, one male homosexual and one female homosexual, and send emails to schools making sexual orientation explicit. Our results show that men homosexual couples had a significant lower probability to receive and answer than heterosexual couples (22.5 percentage points less). No statistically significant differences in the response rate were found between female homosexual and heterosexual couples. This result suggests that male homosexual couples might be penalized because of the lack of a maternal figure. Keywords: Discrimination, field experiment, schools, homosexual rights. JEL codes: H41, I20, K36

Banks, Lies and Bricks: The Determinants of Home Value Inflation in Spain during the Housing Boom

During the first decade of this century, Spain experienced the most important economic and housing boom in its recent history. This situation led the lending industry to dramatically expand through the mortgage market. The high competition among lenders caused a dramatic lowering of credit standards. During this period, lenders operating in the Spanish mortgage market artificially inflated appraised home values in order to draw larger mortgages. By doing this, lenders gave financially constrained households access to mortgage credit. In this paper, we analyze this phenomenon for this first time. To do so, we resort to a unique dataset of matched mortgage-dwelling-borrower characteristics covering the period 2004–2010. Our data allow us to construct an unbiased measure of property’s over-appraisal, since transaction prices in our data also includes any potential side payment in the transactions. Our findings indicate that i) in Spain, appraised home values were inflated on average by around 30% with respect to transaction prices; ii) creditconstrained households were more likely to be involved in mortgages with inflated house values; and iii) a regional indicator of competition in the lending market suggests that inflated appraisal values were also more likely to appear in more competitive regional mortgage markets. Keywords: Housing demand, appraisal values, house prices, housing bubble, credit constraints, mortgage market. JEL Classification: R21, R31

What explains productivity differentials across spanish cities?

This paper estimates the determinants of productivity differentials across urban areas in Spain. To do so we resort to Spanish Social Security administrative data (MCVL) matched with workers’ fiscal information. We use two-step approach that allows us to control for the confounding effects due to the sorting of more productive workers and more productive firms in bigger cities. Our results indicate that city size is a significant determinant of productivity differentials across Spanish urban areas. We estimate an elasticity of urban agglomeration of 3.3%, which is within the range of values already observed in other countries. We also find that the level of human capital, firm size and the level of industrial specialization also matters in order explain productivity differentials across Spanish cities. Keywords: Agglomeration, wages, productivity, city size. JEL codes: R10, R23, J31

Extrações de óleos de sementes de citros e suas atividades sobre a formiga cortadeira Atta sexdens e seu fungo simbionte

Seeds Citrus oils (C. sinensis, C. limon and C. reticulata) extraction with hexane in a soxhlet apparatus and through supercritical fluid (CO2) were done. Besides triglycerides, the oils obtained with hexane comprised volatile compounds such as terpenes and fatty alcohols, esters, and aldehydes. However, the oils obtained by extraction with supercritical fluid presented only triglycerides. These results indicate that the extraction using supercritical fluid presents better selectivity. The activity of the oils on the development of the ant symbiotic fungus, Leucoagaricus gongylophorus, showed week activity and the topic insecticide assay showed better activity for the tangerine seed oil.

A carboxylesterase, Esterase-6, modulates sensory physiological and behavioural response dynamics to pheromone in Drosophila

Background: Insects respond to the spatial and temporal dynamics of a pheromone plume, which implies not only a strong response to"odor on", but also to"odor off". This requires mechanisms geared toward a fast signal termination. Several mechanisms may contribute to signal termination, among which odorant-degrading enzymes. These enzymes putatively play a role in signal dynamics by a rapid inactivation of odorants in the vicinity of the sensory receptors, although direct in vivo experimental evidences are lacking. Here we verified the role of an extracellular carboxylesterase, esterase-6 (Est-6), in the sensory physiological and behavioral dynamics of Drosophila melanogaster response to its pheromone, cis-vaccenyl acetate (cVA). Est-6 was previously linked to post-mating effects in the reproductive system of females. As Est-6 is also known to hydrolyze cVA in vitro and is expressed in the main olfactory organ, the antenna, we tested here its role in olfaction as a putative odorant-degrading enzyme. Results: We first confirm that Est-6 is highly expressed in olfactory sensilla, including cVA-sensitive sensilla, and we show that expression is likely associated with non-neuronal cells. Our electrophysiological approaches show that the dynamics of olfactory receptor neuron (ORN) responses is strongly influenced by Est-6, as in Est-6° null mutants (lacking the Est-6 gene) cVA-sensitive ORN showed increased firing rate and prolonged activity in response to cVA. Est-6° mutant males had a lower threshold of behavioral response to cVA, as revealed by the analysis of two cVAinduced behaviors. In particular, mutant males exhibited a strong decrease of male-male courtship, in association with a delay in courtship initiation. Conclusions: Our study presents evidence that Est-6 plays a role in the physiological and behavioral dynamics of sex pheromone response in Drosophila males and supports a role of Est-6 as an odorant-degrading enzyme (ODE) in male antennae. Our results also expand the role of Est-6 in Drosophila biology, from reproduction to olfaction, and highlight the role of ODEs in insect olfaction. Keywords: carboxylesterase, esterase 6, olfaction, pheromone, signal termination

Energy efficiency determinants: An empirical analysis of Spanish innovative firms

This paper examines the extent to which innovative Spanish firms pursue improvements in energy efficiency (EE) as an objective of innovation. The increase in energy consumption and its impact on greenhouse gas emissions justifies the greater attention being paid to energy efficiency and especially to industrial EE. The ability of manufacturing companies to innovate and improve their EE has a substantial influence on attaining objectives regarding climate change mitigation. Despite the effort to design more efficient energy policies, the EE determinants in manufacturing firms have been little studied in the empirical literature. From an exhaustive sample of Spanish manufacturing firms and using a logit model, we examine the energy efficiency determinants for those firms that have innovated. To carry out the econometric analysis, we use panel data from the Community Innovation Survey for the period 2008‐2011. Our empirical results underline the role of size among the characteristics of firms that facilitate energy efficiency innovation. Regarding company behaviour, firms that consider the reduction of environmental impacts to be an important objective of innovation and that have introduced organisational innovations are more likely to innovate with the objective of increasing energy efficiency. Keywords: energy efficiency, corporate targets, innovation, Community Innovation Survey. JEL Classification: Q40, Q55, O31

Ascertaining Key Factors Behind the Coexistence of the Native Ant Species Plagiolepis pygmaea with the Invasive Argentine Ant Linepithema humile (Hymenoptera: Formicidae)

The Argentine ant, Linepithema humile, is a world-wide invasive ant species. Its presence has a strong negative impact on ant diversity. The present study attempts to highlight the reasons for the coexistence of this highly dominant species with Plagiolepis pygmaea, the only native ant species that has proved able to resist the invasion in a natural ecosystem in the north-east of the Iberian Peninsula. To quantify the aggressiveness level of both species we performed aggressiveness tests on workers in different areas: a) Argentine ant workers from areas with P. pygmaea, b) Argentine ant workers from areas without P. pygmaea, c) P. pygmaea from a non-invaded area and d) P. pygmaea from an invaded area. We also confronted Argentine ant workers with P. pallidula and T. nigerrimum. These aggressiveness tests showed that the coexistence of these two species of ants was not due to a habituation process, since the aggressiveness level observed between the four kinds of confrontations were fairly similar. We also found a lack of aggressiveness between Argentine ant workers and P. pygmaea, and highly submissive behavior in the latter when confronted with the invader. The peaceful character of P. pygmaea together with its markedly submissive behavior may be the main factors behind the coexistence of these species in the study area

Effect of Seasonal Dynamics on Queen Densities of the Argentine Ant (Linepithema Humile) in an Invaded Natural Area of the NE Iberian Peninsula

The annual elimination of large numbers of Argentine ant queens near the advance front of an invasion could be a useful tool for weakening the species’ dispersion and, therefore, limiting its establishment in non-invaded areas. However, before carrying out trials to test the effectiveness of this method it would be essential to have sufficient knowledge of the effect of seasonal dynamics acting on the queens’ densities of the species in order to determine the most favourable period of the year to act. We analyzed the seasonal densities and nest dynamics of Argentine ant queens in an invaded Mediterranean natural ecosystem. We observed that the queens’ density varied depending on the season of the year and that this variation was mainly due to the seasonal dynamics of nest aggregations in winter and ant dispersions in summer. The greatest densities per litre of nest soil were observed in winter (December to March, approximately) and the lowest densities were observed in summer ( June to July). This information is essential for improving current knowledge of the Argentine ant’s biology and developing control methods based on the elimination of queens in invaded natural areas

Some Notes and Comments on the Efficient use of Information in Repeated Games with Poisson Signals

In the present paper we characterize the optimal use of Poisson signals to establish incentives in the "bad" and "good" news models of Abreu et al. [1]. In the former, for small time intervals the signals' quality is high and we observe a "selective" use of information; otherwise there is a "mass" use. In the latter, for small time intervals the signals' quality is low and we observe a "fine" use of information; otherwise there is a "non-selective" use. JEL: C73, D82, D86. KEYWORDS: Repeated Games, Frequent Monitoring, Public Monitoring, Infor- mation Characteristics.

Reduction of the Ant Mandible Gap Range After Biotic Homogenization Caused by an Ant Invasion (Hymenoptera: Formicidae)

After most of the native ant species are displaced by the Argentine ant invasion, it is probable that some ecological processes carried out by natives are not replaced. In some cases this could be due to a morphological difference between the Argentine ant and the displaced native ants. The significant decrease in ant richness after the invasion (only two species detected in the invaded zones vs. 25 species in surrounding non-invaded zones) implies a drastic reduction in the ant mandible gap range (the mandible gap spectra of all the ant species in a community) in the invaded zones. This reduction could explain why some roles that were previously carried out by the displaced native species are not performed by the invasive species. This could be due to a functional inability to carry out these activities. The mandible gap waspositively correlated with the ant body mass in the 26 ant species considered. The functional inability hypothesis could be applied to other invasive ants as well as to the Argentine ant

Isolamento do alcalóide ricinina das folhas de Ricinus communis (Euphorbiaceae) através de cromatografias em contracorrente

Droplet counter-current chromatography, rotation locular counter-current chromatography and high-speed counter-current chromatography were applied to the preparative separation of the alkaloid ricinine from the dichloromethane extracts of Ricinus communis leaves. The solvent system used was composed of dichloromethane-methanol-water (93:35:72 v/v/v) and all techniques led to the isolation of large amounts of the alkaloid. The best result was obtained through HSCCC, since the ricinine yield was respectively 50% and 30% higher than when using RLCCC or DCCC.

Effects of Weight Loss on Adipose Tissue, Liver and Heart Metabolism in Humans

Obesity has become the leading cause of many chronic diseases, such as type 2 diabetes and cardiovascular diseases. The prevalence of obesity is high in developed countries and it is also a major cause of the use of health services. Ectopic fat accumulation in organs may lead to metabolic disturbances, such as insulin resistance.Weight loss with very-low-energy diet is known to be safe and efficient. Weight loss improves whole body insulin sensitivity, but its effects on tissue and organ level in vivo are not well known. The aims of the studies were to investigate possible changes of weight loss in glucose and fatty acid uptake and perfusion and fat distribution at tissue and organ level using positron emission tomography and magnetic resonance imaging and spectroscopy in 34 healthy obese subjects. The results showed that whole-body insulin sensitivity increased after weight loss with very-low-energy diet and this is associated with improved skeletal muscle insulin-stimulated glucose uptake, but not with adipose tissue, liver or heart glucose uptake. Liver insulin resistance decreased after weight loss. Liver and heart free fatty acid uptakes decreased concomitantly with liver and heart triglyceride content. Adipose tissue and myocardial perfusion decreased. In conclusion, enhanced skeletal muscle glucose uptake leads to increase in whole-body insulin sensitivity when glucose uptake is preserved in other organs studied. These findings suggest that lipid accumulation found in the liver and the heart in obese subjects without co-morbidies is in part reversible by reduced free fatty acid uptake after weight loss. Reduced lipid accumulation in organs may improve metabolic disturbances, e.g. decrease liver insulin resistance. Keywords: Obesity, weight loss, very-low-energy diet, adipose tissue metabolism, liver metabolism, heart metabolism, positron emission tomography

Els «criteris de visibilització de les dones» en català: límits sintacticosemàntics i discursius

L'objectiu d'aquest article és analitzar els principals criteris que les guies d'estil recomanen per visibilitzar les dones ¿o per fer un ús no sexista del llenguatge¿ des de dos punts de vista: el sintacticosemàntic i el discursiu. Des del punt de vista sintacticosemàntic, s'estudien bàsicament els fenòmens relacionats amb la coordinació, la concordança i la repetició o elisió d'elements (per exemple, especificadors del nom), i la manera com les diferents opcions afecten el significat oracional. Des del punt de vista discursiu, s'analitzen els fenòmens relacionats amb la coreferència; és a dir, la relació entre les diferents maneres d'expressar un mateix referent per mitjà d'elements nominals al llarg del text, i l'efecte que provoquen en el text en conjunt. Amb aquest objectiu, l'estudi analitza des d'un punt de vista qualitatiu les dades proporcionades per un corpus de textos procedents de tres àmbits (polític, administratiu i educatiu) en què s'apliquen sovint aquesta mena de criteris. Paraules clau: català, llenguatge no sexista, visibilització lingüística de les dones, sintaxi, cohesió, coreferència, llenguatge androcèntric, estil. The goal of this article is to analyse the main criteria recommended by style guides aimed at making women more visible or, in other words, to make a non-sexist use of language. I will concentrate on two main aspects: the syntactic-semantic and the discursive. From a syntactic-semantic point of view, the main elements being studied are those related to coordination, agreement and repetition or omission of elements (for instance, noun specifiers), and also the way the different options chosen affect the meaning of the sentence. From a discursive and stylistic point of view, the elements analysed are those related to coreference, that is, the relationship between the different ways of expressing a same referent through different elements in the text, and the effect they produce in the text as a whole. Having this as the main goal, the study analyses from a qualitative point of view the data from a corpus in three different areas (politics, administration and education), which often apply this kind of criteria. Keywords: Catalan, non-sexist language, female linguistic visibility, syntax, cohesion, co-reference, androcentric language, style