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351.
O. E. Diekmann L. Gouveia J. A. Perez C. Gil-Rodriguez E. A. Serrão 《Marine Biology》2010,157(9):2109-2115
Seagrasses and their habitat are declining worldwide. Zostera noltii in the Canary Islands has been drastically reduced, mainly by anthropogenic disturbance, to three small surviving patches
in a single harbor in Lanzarote. A previous genetic study, using neutral microsatellite markers, revealed that these patches
consist of a single clonal individual. Here, an assignment test, using microsatellite data, was used to locate the most likely
population of origin from a set of possible donor populations. Our results show that the Moulay Bousselham population in northern
Morocco is assigned as the most likely population of origin (88%), although the probability of being at one generation time
distance is low (2.7%). This result, however, allows locating the most closely related stands that may be the most successful
donor populations for future restoration based on shoot or seed transplantation. 相似文献
352.
Helen M. de la Maza Jerry O. Wolff Amber Lindsey 《Behavioral ecology and sociobiology》1999,45(2):107-113
A widely accepted paradigm in mammalian behavioral biology is that exposure to unfamiliar males causes pregnancy disruption
in female rodents (commonly known as the Bruce effect). This behavioral phenomenon has been demonstrated in the laboratory
with at least 12 species of rodents, primarily within the genus Microtus, and is supposedly an adaptation that provides male perpetrators with reproductive access to females, and functions, for
females, as a counterstrategy to infanticide. However, neither the Bruce effect nor its adaptive significance have been tested
experimentally in the field. In a controlled field study, we exposed reproducing female gray-tailed voles (Microtus canicaudus) to treatments in which males were removed and replaced by either unfamiliar males or females, and found no significant differences
in intervals between parturitions, number of pregnancies, and juvenile recruitment among the treatment and control animals.
Thus, we conclude that neither the Bruce effect nor infanticide occurred differentially as a consequence of the treatments
in gray-tailed voles. Multimale mating to confuse paternity, and postpartum estrus resulting in simultaneous pregnancy and
lactation may deter infanticide and functionally negate any benefits of pregnancy disruption in gray-tailed voles and perhaps
other murid rodents with similar mating systems. In light of our results, we recommend field verification for other species
of murid rodents that exhibit the Bruce effect in the laboratory before the results are applied to evolutionary theory.
Received: 12 May 1998 / Accepted after revision: 6 September 1998 相似文献
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358.
Carlos Navarro Florentino de Lope Anders Pape Møller 《Behavioral ecology and sociobiology》2007,61(8):1161-1168
Homeobox genes regulate development of digits, and it has been suggested that the ratio of length of second to length of fourth
digit reflects such genetic effects in a sex-specific manner. We show that digit ratios in the sexually dichromatic house
sparrow Passer domesticus differ between sexes, with males having higher ratios than females, and that individuals produce consistent ratios on the
two feet. If Homeobox or other genes had pleiotropic effects on development of digits, behavior, and physiology of males and
females, we would expect secondary sexual characters and immunity to be related to digit ratio in a sex-specific manner. The
size of the visible part of the black badge in February (a secondary sexual character), but not total badge size, was positively
correlated with digit ratios, suggesting that males with more male-like digit ratios had larger visible badges. Because of
sex-specific effects of development on secondary sexual characters and immunity, we predicted sex-specific differences in
immune response to be related to digit ratio. House sparrows with large digit ratios had weaker T cell-mediated immune response
than individuals with small digit ratios, particularly in females, implying that females with more male-like digit ratios
had weak immune responses. These findings are consistent with the hypothesis that early development, as reflected by digit
ratios, and genetics affect the expression of adult characters that are supposedly strongly contributing to fitness. 相似文献
359.
Otávio José de Oliveira Camila Roberta Muniz Serra Pinheiro 《Journal of Cleaner Production》2009,17(9):883-885
Among the difficulties found in the implementation of ISO 14001 systems, resistance to change can always be found. It is mainly a consequence of the hurry to change, loss of focus, concentration of decision making at the level of top management, arbitrary imposition of objectives and results, faulty communication, and the absence of motivational and financial incentive for change.Therefore, the main objective of this paper is to present best practices with respect to the management of organizational change due to the implementation of ISO 14001 norms in two industrial companies in the Midwest region of the State of São Paulo – Brazil. 相似文献
360.