1000 resultados para Savart, Nic.-Pierre-Ant.
Resumo:
Revision actual de las Uniones Temporales de Empresas (UTE), con el objeto de constatar si la informacion contable que presentan las empresas asociadas mediante esta formula es fidedigna y cual es su situacion ante la reforma contable. La investigacion consta de una parte teorica y una parte empirica. La parte teorica define la union temporal de empresas, sus caracteristicas y objetivos, el origen historico y la regulacion contable, fiscal y juridica que les afecta. Asimismo, se trata con especial relevancia la adaptacion sectorial del PGC a las Empresas Constructoras (PSEC). Por otra parte, se analizan las Normas Internacionales de Informacion Financiera (NIIF) relacionadas con las UTE. Finalmente, se comparan las normas contables españolas, internacionales y francesas referidas a los contratos de larga duracion. La parte empirica, resulta de un analisis de los estados financieras del periodo 2002-2004 de una poblacion de treinta empresas constructoras que habitualmente realizan UTE, la mayoria de las mismas forman parte del SEOPAN (Asociacion de Empresas Constructoras de ambito nacional).
Resumo:
Collection : The New York Herald ; Sunday, April 8, 1906, Easter supplement
Modèles des caractères de l'imprimerie... nouvellement gravés par Simon-Pierre Fournier le jeune,...
Resumo:
Understanding levels of population differentiation and inbreeding are important issues in conservation biology, especially for social Hymenoptera with fragmented and small population sizes. Isolated populations are more vulnerable to genetic loss and extinction than those with extended continuous distributions. However, small populations are not always a consequence of a recent reduction of their habitat. Thus, determining the history of population isolation and current patterns of genetic variation of a species is crucial for its conservation. Rossomyrmex minuchae is a slave-making ant with patchy distribution in South Eastern Spain and is classified as vulnerable by the IUCN. In contrast, the other three known species of the genus are presumed to show more uniform distributions. Here we investigate the genetic diversity and population structure of R. minuchae and compare it with that found in two other species of the genus: R. anatolicus and R. quandratinodum. We conclude that although genetic diversity of R. minuchae is low, there is no evidence of a recent bottleneck, suggesting a gradual and natural fragmentation process. We also show extreme population differentiation at nuclear and mitochondrial markers, and isolation by distance at a local scale. Despite some evidence for inbreeding and low genetic variation within populations, we found almost no diploid males, a finding which contrasts with that expected in inbred Hymenoptera with single locus complementary sex determination. This could mean that sex is determined by another mechanism. We argue that continued low population size means that detrimental effects of inbreeding and low genetic variation are likely in the future. We suggest that a policy of artificial gene flow aimed at increasing within population variation is considered as a management option.
Resumo:
Asexual reproduction is particularly common among introduced species, probably because it helps to overcome the negative effects associated with low population densities during colonization. The ant Cerapachys biroi has been introduced to tropical and subtropical islands around the world since the beginning of the last century. In this species, workers can reproduce via thelytokous parthenogenesis. Here, we use genetic markers to reconstruct the history of anthropogenic introductions of C. biroi, and to address the prevalence of female parthenogenesis in introduced and native populations. We show that at least four genetically distinct lineages have been introduced from continental Asia and have led to the species' circumtropical establishment. Our analyses demonstrate that asexual reproduction dominates in the introduced range and is also common in the native range. Given that C. biroi is the only dorylomorph ant that has successfully become established outside of its native range, this unusual mode of reproduction probably facilitated the species' worldwide spread. On the other hand, the rare occurrence of haploid males and at least one clear case of sexual recombination in the introduced range show that C. biroi has not lost the potential for sex. Finally, we show that thelytoky in C. biroi probably has a genetic rather than an infectious origin, and that automixis with central fusion is the most likely underlying cytological mechanism. This is in accordance with what is known for other thelytokous eusocial Hymenoptera.
Resumo:
Wood ant species show differences in their social structure, especially in the level of polygyny (number of laying queens per nest) and polydomy (number of nest per colony), both within and between species. We demonstrate here for the first time that Formica lugubris displays two different social forms in close proximity in alpine unmanaged forests of the Swiss National Park. The genetic data (7 microsatellite loci) and field data indicate that one population is mostly monogynous to weakly polygynous (r = 0.438) and monodomous, the second one being polygynous (r = 0.113) and polydomous. Within this latter population new nests are founded by budding, leading to the observed high density of nests. These two different social structures, possibly being two expressions of a same continuum, could be explained by several ecological or environmental factors (e.g. habitat saturation, resource competition) and also historical effects.
Resumo:
[Acte. 1755-01-13. Paris]