The economics of power and control

John Hardman Moore outlines his joint research with Oliver Hart, looking at the economics of power and control and the foundations of contractual incompleteness

Lire, écrire : d'un désir l'autre : le "roman de Meliadus" du XIIIe au XVIIIe siècle

Continuation elleptique du Tristan en prose, qui s'inscrit dans l'interstice séparant la naissance de Tristan du remariage de Méliadus avec la fille du roi Hoël, le Roman de Meliadus (1235-1240) est une oeuvre fondamentalement ouverte, de par son inachèvement et de par le dialogue constant qu'il instaure avec les autres romans arthuriens. S'il revendique sa filiation et assume son statut de récit puîné, les réminiscences qu'il exhibe masquent aussi les gauchissements, les infléchissements qui lui permettent de faire du neuf avec du vieux. C'est ce jeu - aux deux sens du terme - que cette étude se propose de mettre en lumière et de voir fonctionner, non seulement dans le Roman de Meliadus proprement dit, mais également dans trois de ses relectures, qui actualisent et renouvellent la signification du roman en profondeur. La première est une continuation qui date de la toute fin du XIIIe ou du début du XIVe siècle et qui est aujourd'hui conservée par le seul manuscrit Ferrell 5. La deuxième actualisation retenue est celle qu'offre Meliadus de Leonnoys, l'imprimé publié en 1528 par Galliot du Pré, puis en 1532 par Denis Janot, fruit d'un minutieux travail de découpage et de remontage. La dernière enfin est l'extrait paru en 1776 dans la Bibliothèque Universelle des Romans sous le titre Méliadus de Léonnois. An ellipitic continuation of the Prose Tristan, which inscribes itself in the space separating the birth of Tristan from Meliadus' new marriage with king Hoël's daughter, the Meliadus' romance (1235-1240) is essentially an open text on account of its incompleteness and the dialogue it establishes with other arthurian romances. Even asserting filiation status, the reminiscences also show the reshaping and the inflection that allow the text to transform old into new. Analyzing this game is the central purpose of this work; to observe the operation in the Meliadus' romance, as well as in three of its recuperations that profoundly renew the significance of the novel; beginning with a continuation from the end of the 13th century or the early 14th century, preserved nowadays in only one manuscript (Ferrel 5); followed by the meticulous work of cutting and reassembling offered by the Meliadus of Leonnoys (printed by Galliot du Pré in 1528 first and again by Denis Janot in 1532) and finally an excerpt published in 1776 in the Bibliothèque Universelle des Romans with the title Méliadus of Leonnois.

Variability of North Atlantic hurricanes: seasonal versus individual-event features

Tropical cyclones are affected by a large number of climatic factors, which translates into complex patterns of occurrence. The variability of annual metrics of tropical-cyclone activity has been intensively studied, in particular since the sudden activation of the North Atlantic in the mid 1990’s. We provide first a swift overview on previous work by diverse authors about these annual metrics for the North-Atlantic basin, where the natural variability of the phenomenon, the existence of trends, the drawbacks of the records, and the influence of global warming have been the subject of interesting debates. Next, we present an alternative approach that does not focus on seasonal features but on the characteristics of single events [Corral et al., Nature Phys. 6, 693 (2010)]. It is argued that the individual-storm power dissipation index (PDI) constitutes a natural way to describe each event, and further, that the PDI statistics yields a robust law for the occurrence of tropical cyclones in terms of a power law. In this context, methods of fitting these distributions are discussed. As an important extension to this work we introduce a distribution function that models the whole range of the PDI density (excluding incompleteness effects at the smallest values), the gamma distribution, consisting in a powerlaw with an exponential decay at the tail. The characteristic scale of this decay, represented by the cutoff parameter, provides very valuable information on the finiteness size of the basin, via the largest values of the PDIs that the basin can sustain. We use the gamma fit to evaluate the influence of sea surface temperature (SST) on the occurrence of extreme PDI values, for which we find an increase around 50 % in the values of these basin-wide events for a 0.49 C SST average difference. Similar findings are observed for the effects of the positive phase of the Atlantic multidecadal oscillation and the number of hurricanes in a season on the PDI distribution. In the case of the El Niño Southern oscillation (ENSO), positive and negative values of the multivariate ENSO index do not have a significant effect on the PDI distribution; however, when only extreme values of the index are used, it is found that the presence of El Niño decreases the PDI of the most extreme hurricanes.

Selected configuration interaction with truncation energy error and application to the Ne atom

Selected configuration interaction (SCI) for atomic and molecular electronic structure calculations is reformulated in a general framework encompassing all CI methods. The linked cluster expansion is used as an intermediate device to approximate CI coefficients BK of disconnected configurations (those that can be expressed as products of combinations of singly and doubly excited ones) in terms of CI coefficients of lower-excited configurations where each K is a linear combination of configuration-state-functions (CSFs) over all degenerate elements of K. Disconnected configurations up to sextuply excited ones are selected by Brown's energy formula, ΔEK=(E-HKK)BK2/(1-BK2), with BK determined from coefficients of singly and doubly excited configurations. The truncation energy error from disconnected configurations, Δdis, is approximated by the sum of ΔEKS of all discarded Ks. The remaining (connected) configurations are selected by thresholds based on natural orbital concepts. Given a model CI space M, a usual upper bound ES is computed by CI in a selected space S, and EM=E S+ΔEdis+δE, where δE is a residual error which can be calculated by well-defined sensitivity analyses. An SCI calculation on Ne ground state featuring 1077 orbitals is presented. Convergence to within near spectroscopic accuracy (0.5 cm-1) is achieved in a model space M of 1.4× 109 CSFs (1.1 × 1012 determinants) containing up to quadruply excited CSFs. Accurate energy contributions of quintuples and sextuples in a model space of 6.5 × 1012 CSFs are obtained. The impact of SCI on various orbital methods is discussed. Since ΔEdis can readily be calculated for very large basis sets without the need of a CI calculation, it can be used to estimate the orbital basis incompleteness error. A method for precise and efficient evaluation of ES is taken up in a companion paper

Intramolecular basis set superposition error effects on the planarity of benzene and other aromatic molecules: A solution to the problem

Recently, the surprising result that ab initio calculations on benzene and other planar arenes at correlated MP2, MP3, configuration interaction with singles and doubles (CISD), and coupled cluster with singles and doubles levels of theory using standard Pople’s basis sets yield nonplanar minima has been reported. The planar optimized structures turn out to be transition states presenting one or more large imaginary frequencies, whereas single-determinant-based methods lead to the expected planar minima and no imaginary frequencies. It has been suggested that such anomalous behavior can be originated by two-electron basis set incompleteness error. In this work, we show that the reported pitfalls can be interpreted in terms of intramolecular basis set superposition error (BSSE) effects, mostly between the C–H moieties constituting the arenes. We have carried out counterpoise-corrected optimizations and frequency calculations at the Hartree–Fock, B3LYP, MP2, and CISD levels of theory with several basis sets for a number of arenes. In all cases, correcting for intramolecular BSSE fixes the anomalous behavior of the correlated methods, whereas no significant differences are observed in the single-determinant case. Consequently, all systems studied are planar at all levels of theory. The effect of different intramolecular fragment definitions and the particular case of charged species, namely, cyclopentadienyl and indenyl anions, respectively, are also discussed

SGP-1: prediction and validation of homologous genes based on sequence alignments

Conventional methods of gene prediction rely on the recognition of DNA-sequence signals, the coding potential or the comparison of a genomic sequence with a cDNA, EST, or protein database. Reasons for limited accuracy in many circumstances are species-specific training and the incompleteness of reference databases. Lately, comparative genome analysis has attracted increasing attention. Several analysis tools that are based on human/mouse comparisons are already available. Here, we present a program for the prediction of protein-coding genes, termed SGP-1 (Syntenic Gene Prediction), which is based on the similarity of homologous genomic sequences. In contrast to most existing tools, the accuracy of SGP-1 depends little on species-specific properties such as codon usage or the nucleotide distribution. SGP-1 may therefore be applied to nonstandard model organisms in vertebrates as well as in plants, without the need for extensive parameter training. In addition to predicting genes in large-scale genomic sequences, the program may be useful to validate gene structure annotations from databases. To this end, SGP-1 output also contains comparisons between predicted and annotated gene structures in HTML format. The program can be accessed via a Web server at http://soft.ice.mpg.de/sgp-1. The source code, written in ANSI C, is available on request from the authors.

Debt and deficit fluctuations and the structure of bond markets

This paper tests for the market environment within which US fiscal policyoperates, that is we test for the incompleteness of the US government bondmarket. We document the stochastic properties of US debt and deficits andthen consider the ability of competing optimal tax models to account forthis behaviour. We show that when a government pursues an optimal taxpolicy and issues a full set of contingent claims, the value of debthas the same or less persistence than other variables in the economyand declines in response to higher deficit shocks. By contrast, ifgovernments only issue one-period risk free bonds (incomplete markets),debt shows more persistence than other variables and it increases inresponse to expenditure shocks. Maintaining the hypothesis of Ramseybehavior, US data conflicts.

Biased representation of homothetic preferences on homogeneous sets

In the homogeneous case of one-dimensional objects, we show that any preference relation that is positive and homothetic can be represented by a quantitative utility function and unique bias. This bias may favor or disfavor the preference for an object. In the first case, preferences are complete but not transitive and an object may be preferred even when its utility is lower. In the second case, preferences are asymmetric and transitive but not negatively transitive and it may not be sufficient for an object to have a greater utility for be preferred. In this manner, the bias reflects the extent to which preferences depart from the maximization of a utility function.

Evaluating leaf litter beetle data sampled by Winkler extraction from Atlantic forest sites in southern Brazil

Evaluating leaf litter beetle data sampled by Winkler extraction from Atlantic forest sites in southern Brazil. To evaluate the reliability of data obtained by Winkler extraction in Atlantic forest sites in southern Brazil, we studied litter beetle assemblages in secondary forests (5 to 55 years after abandonment) and old-growth forests at two seasonally different points in time. For all regeneration stages, species density and abundance were lower in April compared to August; but, assemblage composition of the corresponding forest stages was similar in both months. We suggest that sampling of small litter inhabiting beetles at different points in time using the Winkler technique reveals identical ecological patterns, which are more likely to be influenced by sample incompleteness than by differences in their assemblage composition. A strong relationship between litter quantity and beetle occurrences indicates the importance of this variable for the temporal species density pattern. Additionally, the sampled beetle material was compared with beetle data obtained with pitfall traps in one old-growth forest. Over 60% of the focal species captured with pitfall traps were also sampled by Winkler extraction in different forest stages. Few beetles with a body size too large to be sampled by Winkler extraction were only sampled with pitfall traps. This indicates that the local litter beetle fauna is dominated by small species. Hence, being aware of the exclusion of large beetles and beetle species occurring during the wet season, the Winkler method reveals a reliable picture of the local leaf litter beetle community.

Bayesian estimation of speciation and extinction from incomplete fossil occurrence data.

The temporal dynamics of species diversity are shaped by variations in the rates of speciation and extinction, and there is a long history of inferring these rates using first and last appearances of taxa in the fossil record. Understanding diversity dynamics critically depends on unbiased estimates of the unobserved times of speciation and extinction for all lineages, but the inference of these parameters is challenging due to the complex nature of the available data. Here, we present a new probabilistic framework to jointly estimate species-specific times of speciation and extinction and the rates of the underlying birth-death process based on the fossil record. The rates are allowed to vary through time independently of each other, and the probability of preservation and sampling is explicitly incorporated in the model to estimate the true lifespan of each lineage. We implement a Bayesian algorithm to assess the presence of rate shifts by exploring alternative diversification models. Tests on a range of simulated data sets reveal the accuracy and robustness of our approach against violations of the underlying assumptions and various degrees of data incompleteness. Finally, we demonstrate the application of our method with the diversification of the mammal family Rhinocerotidae and reveal a complex history of repeated and independent temporal shifts of both speciation and extinction rates, leading to the expansion and subsequent decline of the group. The estimated parameters of the birth-death process implemented here are directly comparable with those obtained from dated molecular phylogenies. Thus, our model represents a step towards integrating phylogenetic and fossil information to infer macroevolutionary processes.

A Behavioral Account of the Labor Market: The Role of Fairness Concerns

In this paper, we argue that important labor market phenomena can be better understood if one takes (a) the inherent incompleteness and relational nature of most employment contracts and (b) the existence of reference-dependent fairness concerns among a substantial share of the population into account. Theory shows and experiments confirm that, even if fairness concerns were to exert only weak effects in one-shot interactions, repeated interactions greatly magnify the relevance of such concerns on economic outcomes. We also review evidence from laboratory and field experiments examining the role of wages and fairness on effort, derive predictions from our approach for entry-level wages and incumbent workers' wages, confront these predictions with the evidence, and show that reference-dependent fairness concerns may have important consequences for the effects of economic policies such as minimum wage laws.

Continental faunal exchange and the asymmetrical radiation of carnivores.

Lineages arriving on islands may undergo explosive evolutionary radiations owing to the wealth of ecological opportunities. Although studies on insular taxa have improved our understanding of macroevolutionary phenomena, we know little about the macroevolutionary dynamics of continental exchanges. Here we study the evolution of eight Carnivora families that have migrated across the Northern Hemisphere to investigate if continental invasions also result in explosive diversification dynamics. We used a Bayesian approach to estimate speciation and extinction rates from a substantial dataset of fossil occurrences while accounting for the incompleteness of the fossil record. Our analyses revealed a strongly asymmetrical pattern in which North American lineages invading Eurasia underwent explosive radiations, whereas lineages invading North America maintained uniform diversification dynamics. These invasions into Eurasia were characterized by high rates of speciation and extinction. The radiation of the arriving lineages in Eurasia coincide with the decline of established lineages or phases of climate change, suggesting differences in the ecological settings between the continents may be responsible for the disparity in diversification dynamics. These results reveal long-term outcomes of biological invasions and show that the importance of explosive radiations in shaping diversity extends beyond insular systems and have significant impact at continental scales.

Endobronchial valves in severe emphysematous patients: CT evaluation of lung fissures completeness, treatment radiological response and quantitative emphysema analysis

OBJECTIVE: To evaluate lung fissures completeness, post-treatment radiological response and quantitative CT analysis (QCTA) in a population of severe emphysematous patients submitted to endobronchial valves (EBV) implantation. MATERIALS AND METHODS: Multi-detectors CT exams of 29 patients were studied, using thin-section low dose protocol without contrast. Two radiologists retrospectively reviewed all images in consensus; fissures completeness was estimated in 5% increments and post-EBV radiological response (target lobe atelectasis/volume loss) was evaluated. QCTA was performed in pre and post-treatment scans using a fully automated software. RESULTS: CT response was present in 16/29 patients. In the negative CT response group, all 13 patients presented incomplete fissures, and mean oblique fissures completeness was 72.8%, against 88.3% in the other group. QCTA most significant results showed a reduced post-treatment total lung volume (LV) (mean 542 ml), reduced EBV-submitted LV (700 ml) and reduced emphysema volume (331.4 ml) in the positive response group, which also showed improved functional tests. CONCLUSION: EBV benefit is most likely in patients who have complete interlobar fissures and develop lobar atelectasis. In patients with no radiological response we observed a higher prevalence of incomplete fissures and a greater degree of incompleteness. The fully automated QCTA detected the post-treatment alterations, especially in the treated lung analysis.

The republican case for workplace democracy

The republican case for workplace democracy (WD) is presented and defended from two alternative means of ensuring freedom from arbitrary interference in the firmnamely, (a) the right to freely exit the firm and (b) workplace regulation. This paper shows, respectively, that costless exit is neither possible nor desirable in either perfect or imperfect labor markets, and that managerial discretion is both desirable and inevitable due to the incompleteness of employment contracts and labor legislation. The paper then shows that WD is necessary, from a republican standpoint, if workers" interests are to be adequately tracked in the exercise of managerial authority. Three important objections are finally addressed (i) that WD is redundant, (ii) that it is unnecessary provided that litigation and unionism can produce similar outcomes, and (iii) that it falls short of ensuring republican freedom compared to self-employment.

Urana työllistyminen

Tutkimuksen tarkoituksena on ollut selvittää pitkään työttömänä olleiden ammatinvaihtajien ammatinvaihdon ja työllistymisen etenemistä. Tämän lisäksi tutkimuksessa on tarkasteltu kohderyhmän mielikuvaa ohjaavasta koulutuksesta. Pitkittäistutkimus on toteutettu seurannalla, jonka välietappina on ollut kohderyhmän osallistuminen ohjaavaan koulutukseen. Työvoimapoliittinen ohjaava koulutus edusti erityisesti vaikeasti työllistettäville kohdistettavaa interventiota, jolla pyrittiin puuttumaan työttömyyskierteeseen ja ehkäisemään syrjäytymiskehityksen jatkuminen. Tutkimuksen kohderyhmäksi valitut ihmiset (51) ovat suoranaisessa keskiössä tutkittaessa työelämästä syrjäytymistä. Heikentyneet työelämävalmiudet ja työmarkkinakelpoisuus ovat tehneet heistä vaikeasti työllistettäviä. Heidän valintansa kohderyhmäksi, työhallinnon tekemän kurssiosoituksen kriteereinä olevien pitkäaikaistyöttömyyden sekä epäonnistuneen ammatinvaihdon perusteella, osoittaa heidän olevan erityisen ohjauksen ja tuen tarpeessa. On kuitenkin huomattava, että heidät on valittu kohderyhmäksi paitsi kurssiosoituksen saaneina pitkäaikaistyöttöminä myös ammatinvaihtajina, jotka itse haluavat vaihtaa ammattiaan. Tutkimusaineistona ovat olleet työhallinnon asiakasrekisteritiedot ja seurantatutkimuksen perusteella muodostetuista ryhmistä valittujen neljän tapaushenkilön teemahaastatteluaineistot. Tutkimusaineistoa on käsitelty laadullisesti, koska tutkimus kuuluu laadullisen tutkimuksen piiriin sekä tutkimuksen kohteena olevan ilmiön, tutkimuskysymysten ja -aineistojen että tarkoituksensa perusteella. Tutkimuksessa on kuvattu pitkäaikaistyöttömien henkilöiden ammatinvaihtoa ja työllistymistä. Kuvatuissa tapauksissa ammatinvaihtotarve perustuu suurimmalla osalla terveydellisiin rajoitteisiin, joiden vuoksi aikaisemmassa työssä toimiminen on mahdotonta. Useimmiten vajaakuntoisuus on merkittävästi pitkittänyt heidän työttömyyttään. Tämän vuoksi seurantatutkimuksessa on keskitytty tarkastelemaan ammatinvaihtoprosessin etenemistä. Muun muassa työttömyyttä laajasti tutkineet Aho ja Vähätalo ovat todenneet vajaakuntoisuuden olevan merkittävä työttömyyden pitkittymiseen vaikuttava tekijä. Ahon mukaan vajaakuntoisiksi diagnosoituja on jopa viidennes kroonisesti pitkäaikaistyöttömistä työhallinnon asiakasrekisteriin kirjatuista henkilöistä. Monen tekijän summana pitkään työttömänä olleet henkilöt ovat vaarassa ajautua tilanteeseen, jossa he eivät enää kykene omin avuin löytämään ulospääsyä työttömyydestä Tämän seurantatutkimuksen perusteella vain hyvin harvalla kohderyhmään kuuluvista on ammatinvaihdossa ja työllistymisessä tapahtunut merkittävää edistymistä huolimatta useiden vuosien yrittämisestä. Ammatinvaihdon ja työllistymisen edistymistä on tarkasteltu sen perusteella, miten työelämään ja/tai koulutukseen sijoittumiset tai muut toiminnot ovat edesauttaneet tavoitteen toteutumista. Seurantatutkimuksessa on muodostettu neljä tyyppiryhmää ammatinvaihdon ja työllistymisen etenemisen perusteella. Ryhmät ovat: Ammatinvaihdossa onnistuneet (5), ammatinvaihdossa edistyneet (19), pitkäaikaistyöttömäksi jääneet (12) ja epätarkoituksenmukaisesti sijoittuneet (15). Ammatinvaihdossa onnistuneet ovat toteuttaneet ammatinvaihtonsa siirtymällä suoraan työelämään uudelle alalle, työllistymällä koulutusta vastaavaan työhön uudelleenkoulutuksen jälkeen tai kouluttautumalla uuteen ammattiin työllistymättä. Kuitenkin vain kolme heistä on sijoittunut seurannan päättyessä pysyväisluonteiseen terveydelleen soveltuvaan työhön muiden ollessa edelleen työttömänä. Ammatinvaihdossa edistyneet ovat suurimmaksi osaksi edistyneet ammatinvaihdossaan soveltuvien tukitöiden avulla. Työttömyys on kuitenkin jatkunut valtaosalla ja vain yksi heistä on sijoittuneena työelämään seurannan päättyessä. Tämä sijoittuminen ei ole kuitenkaan edistänyt ammatinvaihtoa. Pitkäaikaistyöttömäksi jääneet ovat olleet yhtäjaksoisesti työttömänä kokoseurantajakson ajan. Epätarkoituksenmukaisesti sijoittuneet ovat enimmäkseen sijoittuneet terveytensä kannalta haitallisiin ja/tai ammatinvaihtosuunnitelmilleen soveltumattomiin sijoitustöihin ja määräaikaisuuksiin. Seurannan päättyessä heovat joko työttömänä tai toimivat ammatinvaihtotavoitteensa kannalta haitallisissa työtehtävissä. Tämä on vahvistanut mielikuvaa, joka usealle heille on muodostunut ohjaavasta koulutuksesta työttömille suunnattuna sanktiona, joka ei edistä työllistymistä. Ohjaavassa koulutuksessa suurin osa heistä on kokenut hyötyneensä työharjoittelujaksosta, joka on antanut käyttökelpoista tietoa ammatinvalintaa varten. Lukuun ottamatta kolmea henkilöä, jotka ovat seurannan päättyessä pysyväisluonteisessa työssä terveydelleen soveltuvassa ammatissa, ovat kaikki muut kohderyhmään kuuluvat edelleen erityisen ohjauksen ja tuen tarpeessa johtuen ammatinvaihdon keskeneräisyydestä ja/tai työttömyyden jatkumisesta. Yhdistävänä tekijänä ammatinvaihdossa onnistuneilla vaikuttaa olleen tulevaisuususkon säilyminen pitkäaikaistyöttömyydessä. Sekä ammatinvaihdossa onnistuneet että edistyneet ovat kokeneet työttömyyteen katkoksia tuoneet työt merkityksellisinä riippumatta siitä, ovatko työtehtävät edistäneet ammatinvaihtoa.