S-shaped utility, subprime crash and the black swan

I propose an S-shaped utility function of consumption which, combined with an heterogeneous agents and external habit setting, fits well the first order moments of the American financial and macroeconomic time series relevant for the equity premium puzzle in the second half of XX century. The average relative risk aversion of the agents remains in the 0-3 range. A "black swan"-kind phenomenon makes two of the 50 years considered (the two oil shocks) responsible for half the average of the stochastic discount factor, thus bringing the annual subjective discount factor to a very low level, around 0.5, which solves the risk-free puzzle. The shape of the relative risk aversion function of consumption suggests an explanation for the 2008 suprime crash akin to the breaking of waves on a beach in a lifecycle overlapping generations model.financial puzzles; subprime crash; black swan; S-shaped utility

Ecology, culture and utilisation of the mussel, Brachidontes recurvus (Rafinesque), in the context of an integrated management approach to Boca del Rio-Mandinga estuarine system, Mexico

The ecology and culture potential of the mussel, Brachidontes recurvus (Rafinesque) was investigated in the estuarine system of Boca del Rio-Mandinga, Veracruz, Mexico in order to establish the basis for its possible cultivation and utilisation in the context of integrated resource management. This large ecosystem consists of three lagoons connected by channels or Esteros (total area, 2350 ha); its dynamic hydrobiological characteristics are mainly determined by the interaction of tidal cycles with the rainy and north wind seasons. This results in important spatial and temporal changes in temperature and salinity distribution in the system which influence the life cycle of Brachidontes recurvus. A decrease in salinitv and an increase in temperature triggers the main spawning period of this mussel in August, September and October, although the mussel population is reproductively active year round as shown by gonad development indices (Condition Factor and Seed Mean Gonadic Index), and the temporal occurence of mussel larvae and spatfall. Recruitment of mussel spat occurs over most of the year on the sub-tidal mussel beds, whereas spat settement on aerial mangrove toots appears to be determined by salinity stratification and substratum availability. Natural overcrowding limits growth of wild mussels and their mortality is caused by prolonged, extreme changes in salinity or by asphyxia or predation. Asphyxia kills approximately 80 % of the mussels forming aerial mangrove root clusters because pans of the clusters are knocked off by water currents and the mussels sink into the soft muddy susbtratum and suffocate. Based on the physical and physiological requirements of Brachidontes recurvus. Laguna Redonda has suitable physiographic and hydrobiological conditions for rearing mussels stocked in polypropylene onion bags suspended from wooden racks. Based on a preliminary analysis, socioeconomic factors also seem to be favourable for mussel culture. Mussel seed (30 mm) can be obtained from the natural population, using polypropylene onion bags as collectors or as by-catch from the local oyster fishery. Using this culture method, mussels can attain a minimum commercial size (50 mm) in 6 month at an avenge growth rate of 4 mm/month. Annual minimum yields of 20 tons of mussels from a one hectare culture area in the most favourable zone of the estuarine system can be expected, but production for direct human consumption may be limited at present to a demand of approximate 20 kilos/week by local restaurants. Two identified environmental constraints on commercial mussel culture are potential losses from bird predation and organic pollution caused by the discharge of untreated sewage into the estuarine system. Concentrations of coliform bacteria above the maxima recommended by international health agencies were registered in the water column and in mussel flesh analyzed during this study, especially when salinity was low. While a small volume of cultivated mussels, after proper cleaning and cooking, could be consumed in local restaurants, nutrition trials indicated that larger quantities could be used successfully as a dietary component for cultured caridean and penaeid prawns. A scheme for including mussels as part of the food chain in an integrated multispecies production system is proposed. The culture of Brachidontes recurvus should be established in Laguna Redonda, as part of this approach which includes an estuarine aquatic polyculture system (fish-molluscs-crusutceans) and an integrated fish farm operable on a family basis using traditionally reared animals and plants. Preliminary assessment indicates that optimisation of energy flow could be obtained by recycling non utilised energy produced by both sub-systems, through integration. These proposals and the information presented on Brachidontes recurvus, are provided as a baseline for the future testing of possible ecodevelopment schemes for Boca del Rio-Mandinga in order to establish a sustainable, multiple use management policy for this important tropical coastal ecosystem

Pro-Ecological Commitment in the Words of its Practitioners

O compromisso pró-ecológico (CPE) compreende uma relação de caráter positivo que as pessoas estabelecem com o meio ambiente, manifestada por via de práticas de cuidado ambiental. Para aprofundar o conhecimento sobre esse fenômeno psicossocioambiental, o objetivo foi explorar as definições sobre o CPE a partir do ponto de vista de pessoas comprometidas pró-ecologicamente, e as concepções de meio ambiente que o embasam. Pessoas indicadas como comprometidas pró-ecologicamente (N = 29; idades entre 23 e 79 anos) discorreram livremente em entrevistas sobre seu CPE, sobre meio ambiente e indicaram outras pessoas avaliadas como sendo comprometidas. O corpus foi submetido à análise de conteúdo interpretativa. Identificamos mudanças nos entendimentos de meio ambiente, que se distinguiu do conceito de natureza, e de CPE atreladas aos contextos sócio-históricos e às experiências pessoais. Foram mencionadas práticas relativas às escolhas cotidianas, saúde, conscientização e relações de caráter pró-social, assim como barreiras e hábitos que dificultam o cuidado ambiental.A pro-ecological commitment (PEC) is a positive relationship people establish with the environment and is manifested through environmental care practices. In order to deepen knowledge of this psychosocial and environmental phenomenon, we explored the definitions of PEC from the perspectives of people committed to the environment, taking into account the environmental conceptions underpinning this commitment. People who were nominated as being pro-ecologically committed (N = 29; aged between 23 and 79 years old) freely talked about their PECs and environment and also nominated other people they deemed to have the same commitment. The corpus was analyzed according to interpretive content analysis. We identified changes in their understandings concerning PEC and the environment, which was distinguished from the concept of nature, linked to socio-historical contexts and personal experiences. Practices related to daily choices, health, sensitization and pro-social relations, as well as barriers and habits that hinder environmental care, were also reported

Export of bathyal benthos to the Atlantic through the Mediterranean outflow: Sponges from the mud volcanoes of the Gulf of Cadiz as a case study

Este artículo contiene 20 páginas, 14 figuras, 5 tablas.The Mediterranean is a semi-enclosed sea, with a narrow natural connection —the Strait of Gibraltar— through its western basin to the North Atlantic. Many studies have investigated how the inflow of North Atlantic Surface water into the Mediterranean shapes the faunal composition and abundance of the shallow-water benthic communities of the Western Mediterranean. However, the reverse effect remains little explored, that is, at what level the relatively deep (>200 m deep) outflow of Mediterranean water (MOW) exports bathyal Mediterranean benthos into the North Atlantic and what is the fate of the exported fauna. In this study, we have investigated that process, using the bathyal sponge fauna known from a total of 9 biogeographical areas in the Northeastern Atlantic and 9 in the Western and Central Mediterranean, which accounted for a total of 456 spp. Prior to this general analysis, an exhaustive description of the bathyal sponge fauna (82 spp.) associated to 8 mud volcanoes located in the Gulf of Cadiz (Eastern North Atlantic) was conducted. This was necessary because the bathyal sponge fauna in the North Atlantic zone adjacent to the Strait of Gibraltar remained relatively poorly studied and that situation hindered relevant comparisons with the much better known bathyal fauna of the Western Mediterranean. The results of the clustering, ordination and regression analyses first revealed that the bathyal sponge fauna described from the mud volcanoes field in the Gulf of Cadiz was not essentially different from that previously described in pre-existing studies of other bathyal environments in the Gulf of Cadiz. The large scale subsequent assessment across the Atlantic-Mediterranean biogeographical gradient revealed that the sponge faunas of all Western Mediterranean areas form a relative cohesive group, except for the idiosyncratic nature of the Tyrrhenian Sea. More importantly, the deep-sea sponge fauna of the Gulf of Cadiz (in the easternmost Atlantic side of the Atlantic-Mediterranean gradient) showed more affinity with the fauna of the Western Mediterranean than with the fauna of the remaining Northeastern Atlantic areas considered in the study (i.e., Cape Verde, Canary Islands, Madeira, the Moroccan slope, Lusitanian Banks, Southern Azores Banks and Azores). The Mediterranean area with the highest faunal similarity to the Gulf of Cadiz was the Alboran Sea, followed by the Gulf of Lion, the Strait of Sicily and, the Gulf of Taranto, sharing collectively about 17% of their species. These patterns of faunal affinities clearly illustrate the importance of the MOW in transporting components of the Mediterranean deep-sea sponge communities towards the bathyal communities of the Gulf of Cadiz. The contrasting low faunal affinity between the deep-water sponge fauna of the Gulf of Cadiz and the remaining North Atlantic areas considered in the analyses also revealed that the Mediterranean faunal export is largely circumscribed to the Gulf of Cadiz. It is likely that the North-Atlantic trajectory of the MOW, turning north after the Strait of Gibraltar and staying attached to the slope of the Iberian margin, hinders subsequent colonization of the slopes of the Macaronesia region by the deep-water Mediterranean sponges exported to the Gulf of Cadiz. The results of this study, combined with previous literature on biogeographical sponge transport by marine currents, suggest that the sponge fauna provides a useful tool to reveal the future shifts in the biogeographic patterns predicted in our man-impacted and changing ocean.This research has benefited from funds of two grants of the European Community (LIFE + INDEMARES 07/NAT/E/000732 and INTEMARES LIFE15 IPE/ES/ 000012) awarded to co-authors at the IEO. Likewise, this research has benefited from funds of a Spanish Ministry of Economy and Competitiveness grant (MINECO– CTM2015-6722-1R) and a European Union Horizon 2020 SponGES (no. 679849) grant awarded to the CEAB-CSIC.Peer reviewe

Evolutionary Relationships Beyond Fold Boundaries

The comparative study of protein sequences and structures is traditionally used to better understand protein fold evolution. The insights we gain from our evolutionary analyses are applied in protein design projects. At the same time, we engineer proteins to test evolutionary assumptions; thus, we establish a feedback loop between both aspects of protein science. First, we compared Profile Hidden Markov Models, state of the art tools for homology detection, that represent all structures that adopt the (βα)8-barrel and the flavodoxin-like fold to discover an evolutionary relationship between these basic structural forms. Moreover, we located the region of the sequence space where both folds are most closely related. Having found this interface, we performed remote homologous searches and protein clustering to find sequences with intermediate features between the (βα)8-barrel and the flavodoxin-like fold. We determined the x-ray crystal structure of one of these sequences to learn possible scenarios of fold change during the evolution of these ancestral structures. The intermediate sequence, named NTM0182, displayed features towards both folds. Moreover, and by structurally superimposing the three structures, we found classical evidences of homology among the three folds: high sequence identity over long aligned fragments. Our approach then starts by using very sensitive novel tools for homology detection (probability scores), to find intermediary links that provide classical evidences of common ancestry (high sequence identity). Next, we extended the Profile Hidden Markov Model comparisons to include all folds classified as α/β in the Structural Classification of Proteins (SCOP). Our comparisons showed that high scoring pairwise alignments are correlated with high local structural similarities between different folds. This observation inspired us to look for interchangeable sub-domain size protein fragments, related by sequence and structure, to build chimeric proteins and mimic protein fold evolution. Our global comparisons revealed that both, the flavodoxin-like and the (βα)8-barrel folds were related to Periplasmic binding protein-like I proteins. We then employed sequence comparisons, structural superpositions, homology modeling and computational assessments to engineer a novel chimeric protein by fusing a flavodoxin-like fold protein into a PBP-like scaffold. The chimera turned out to be a well-folded protein with native-like properties. Thus, our research allowed us to gain evolutionary insights that are applied to protein engineering. In this respect, we establish a feedback loop between fold evolution and protein engineering. We finally contribute to an emergent vision where proteins from different folds are evolutionary related

Efeitos de memoria em osciladores quanticos

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e Matematicas2012-10-16T04:51:04

A Real Time Expert System For Decision Making in Rotary Railcar Dumpers

Non