496 resultados para Annuity puzzle


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Within an evolutionary framework of Gastrotricha Marinellina flagellata and Redudasys fornerise bear special interest, as they are the only Macrodasyida that inhabit freshwater ecosystems. Notwithstanding, these rare animals are poorly known; found only once (Austria and Brazil), they are currently systematised as incertae sedis. Here we report on the rediscovery of Redudasys fornerise, provide an account on morphological novelties and present a hypothesis on its phylogenetic relationship based on molecular data. Methodology/Principal Findings: Specimens were surveyed using DIC microscopy and SEM, and used to obtain the 18 S rRNA gene sequence; molecular data was analyzed cladistically in conjunction with data from 42 additional species belonging to the near complete Macrodasyida taxonomic spectrum. Morphological analysis, while providing new information on taxonomically relevant traits (adhesive tubes, protonephridia and sensorial bristles), failed to detect elements of the male system, thus stressing the parthenogenetic nature of the Brazilian species. Phylogenetic analysis, carried out with ML, MP and Bayesian approaches, yielded topologies with strong nodal support and highly congruent with each other. Among the supported groups is the previously undocumented clade showing the alliance between Redudasys fornerise and Dactylopodola agadasys; other strongly sustained clades include the densely sampled families Thaumastodermatidae and Turbanellidae and most genera. Conclusions/Significance: A reconsideration of the morphological traits of Dactylopodola agadasys in light of the new information on Redudasys fornerise makes the alliance between these two taxa very likely. As a result, we create Anandrodasys gen. nov. to contain members of the previously described D. agadasys and erect Redudasyidae fam. nov. to reflect this novel relationship between Anandrodasys and Redudasys. From an ecological perspective, the derived position of Redudasys, which is deeply nested within the Macrodasyida clade, unequivocally demonstrates that invasion of freshwater by gastrotrichs has taken place at least twice, in contrast with the single event hypothesis recently put forward.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Objective This article seeks to explain the puzzle of why incumbents spend so much on campaigns despite most research finding that their spending has almost no effect on voters. Methods The article uses ordinary least squares, instrumental variables, and fixed-effects regression to estimate the impact of incumbent spending on election outcomes. The estimation includes an interaction term between incumbent and challenger spending to allow the effect of incumbent spending to depend on the level of challenger spending. Results The estimation provides strong evidence that spending by the incumbent has a larger positive impact on votes received the more money the challenger spends. Conclusion Campaign spending by incumbents is most valuable in the races where the incumbent faces a serious challenge. Raising large sums of money to be used in close races is thus a rational choice by incumbents.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: The aim was to compare cause-specific mortality, self-rated health (SRH) and risk factors in the French and German part of Switzerland and to discuss to what extent variations between these regions reflect differences between France and Germany. METHODS: Data were used from the general population of German and French Switzerland with 2.8 million individuals aged 45-74 years, contributing 176 782 deaths between 1990 and 2000. Adjusted mortality risks were calculated from the Swiss National Cohort, a longitudinal census-based record linkage study. Results were contrasted with cross-sectional analyses of SRH and risk factors (Swiss Health Survey 1992/3) and with cross-sectional national and international mortality rates for 1980, 1990 and 2000. RESULTS: Despite similar all-cause mortality, there were substantial differences in cause-specific mortality between Swiss regions. Deaths from circulatory disease were more common in German Switzerland, while causes related to alcohol consumption were more prevalent in French Switzerland. Many but not all of the mortality differences between the two regions could be explained by variations in risk factors. Similar patterns were found between Germany and France. CONCLUSION: Characteristic mortality and behavioural differentials between the German- and the French-speaking parts of Switzerland could also be found between Germany and France. However, some of the international variations in mortality were not in line with the Swiss regional comparison nor with differences in risk factors. These could relate to peculiarities in assignment of cause of death. With its cultural diversity, Switzerland offers the opportunity to examine cultural determinants of mortality without bias due to different statistical systems or national health policies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Non-monotone incentive structures, which - according to theory - are able to induce optimal behavior, are often regarded as empirically less relevant for labor relationships. We compare the performance of a theoretically optimal non-monotone contract with a monotone one under controlled laboratory conditions. Implementing some features relevant to real-world employment relationships, our paper demonstrates that, in fact, the frequency of income-maximizing decisions made by agents is higher under the monotone contract. Although this observed behavior does not change the superiority of the non-monotone contract for principals, they do not choose this contract type in a significant way. This is what we call the monotonicity puzzle. Detailed investigations of decisions provide a clue for solving the puzzle and a possible explanation for the popularity of monotone contracts.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the Burgdorf Museum of Ethnology, a mummy rests in a coffin. According to the inventory book, it was purchased from the Cairo Egyptian museum in 1926. The coffin was now examined by Egyptologists and the mummy was radiocarbon dated and examined by Anthropologists. The aim of the study was to compare the results and to check whether mummy and coffin actually belong together. The skull was examined morphological-anthropologically and by CT as a “blank sample”. Coffin and skull imply that the individual was female. The coffin dates to the Ptolemaic period. Only skull bones are preserved, the ethmoid is damaged. CT images Show resinous substances, bone fragments and brain remnants inside the skull. The ethmoid bone was probably foraminated during the mummification process and thus ended up inside the skull. The individual was mummified between the New Kingdom and the Ptolemaic period. Due to its style, it is most probable that the coffin comes from the Gamhud necropolis. The Burgdorf museum of ethnology inventory book chronicles were largely falsified by the examinations. There is a time gap between coffin and the mummy, there are two possible interpretations: the body was mummified with older linen, or the mummy and the coffin do not belong together. The authors strongly advise further investigations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

abgedruckt in: Schopenhauer-Jahrbuch 36 (1955), S 93-94

Relevância:

20.00% 20.00%

Publicador:

Resumo:

El autor reflexiona sobre la influencia de la economía y los cambios históricos en la concepción de la ciencia. A raíz de la caída de la URSS, Martín Pereda considera que la ciencia y la tecnología deben desarrollarse basándose en la cooperación entre las naciones y los científicos.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

En estas palabras, escritas por José Antonio Martín Pereda, e incluidas en una sesión de homenaje al difunto D. Rafael Portaencasa celebrada por la Real Academia de Ingeniería, el autor recuerda cómo era Portaencasa, en qué situación encontró la Universidad Politécnica de Madrid cuando empezó su mandato como Rector y cuáles fueron sus mayores logros.