839 resultados para Revealed preferences
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There has been much debate about the demographic factors that contributed to the outcome of the UK’s referendum on its membership of the EU. Two aspects command special attention. First, there are marked differences between young and old generations in the preferences shown for remaining in the EU. While the former predominantly voted to remain, a great majority of the latter voted to leave. On the other hand, voter turnout revealed the opposite trend: about 83% of UK citizens aged 65 and older voted, whereas only 36% of those aged 18-24 cast their vote (Figure 1).
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Purpose – Bread is one of the most consumed foods in the world, and its main function is to provide nutrients and energy for the body. Thus, the purpose of this paper was to raise awareness about the consumption habits of bread and consumer preferences in the region of Viseu (centre of Portugal), assessing the extent to which the preferences and consumption habits differ based on individual variables. Design/methodology/approach – The study was conducted by means of a questionnaire by direct interviewing. The questionnaire included sections aimed at gathering information about demographics, consumption habits and preferences related to bread. The sample consisted of 500 consented respondents. Findings – The results showed significant differences between genders regarding the type of bread eaten: women consumed less wheat bread (52 per cent against 62 per cent; p 0.029) and less unsalted bread (0.3 per cent against 3 per cent; p 0.023), but more whole bread (25 per cent against 11 per cent; p 0.001) and more bread with cereal grains (23 per cent against 11 per cent; p 0.001), thus revealing a trend for a nutritionally more adequate choice. Accordingly, women valued more the composition of the bread when purchasing it (p 0.001). It was also observed a trend for a lower consumption of wheat bread among classes with more advanced studies (47 per cent on university graduates against 60 per cent on nongraduates; p 0.004). Originality/value – This work is innovative because it was the first time the preferences and consuming habits of a sample of Portuguese population regarding bread were accessed, altogether. The results hereby obtained may be of importance both to understand the nutritional importance of bread in the diet of the Portuguese and also for the industry and manufacturers to better correspond to the buying preferences.
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Female mating preferences can influence both intraspecific sexual selection and interspecific reproductive isolation, and have therefore been proposed to play a central role in speciation. Here, we investigate experimentally in the African cichlid fish Pundamilia nyererei if differences in male coloration between three para-allopatric populations (i.e. island populations with gene flow) of P. nyererei are predicted by differences in sexual selection by female mate choice between populations. Second, we investigate if female mating preferences are based on the same components of male coloration and go in the same direction when females choose among males of their own population, their own and other conspecific populations and a closely related para-allopatric sister-species, P. igneopinnis. Mate-choice experiments revealed that females of the three populations mated species-assortatively, that populations varied in their extent of population-assortative mating and that females chose among males of their own population based on different male colours. Females of different populations exerted directional intrapopulation sexual selection on different male colours, and these differences corresponded in two of the populations to the observed differences in male coloration between the populations. Our results suggest that differences in male coloration between populations of P. nyererei can be explained by divergent sexual selection and that population-assortative mating may directly result from intrapopulation sexual selection.
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The small hive beetle, Aethina tumida, is an emerging pest of social bee colonies. A. tumida shows a specialized life style for which olfaction seems to play a crucial role. To better understand the olfactory system of the beetle, we used immunohistochemistry and 3-D reconstruction to analyze brain structures, especially the paired antennal lobes (AL), which represent the first integration centers for odor information in the insect brain. The basic neuroarchitecture of the A. tumida brain compares well to the typical beetle and insect brain. In comparison to other insects, the AL are relatively large in relationship to other brain areas, suggesting that olfaction is of major importance for the beetle. The AL of both sexes contain about 70 olfactory glomeruli with no obvious size differences of the glomeruli between sexes. Similar to all other insects including beetles, immunostaining with an antiserum against serotonin revealed a large cell that projects from one AL to the contralateral AL to densely innervate all glomeruli. Immunostaining with an antiserum against tachykinin-related peptides (TKRP) revealed hitherto unknown structures in the AL. Small TKRP-immunoreactive spherical substructures are in both sexes evenly distributed within all glomeruli. The source for these immunoreactive islets is very likely a group of about 80 local AL interneurons. We offer two hypotheses on the function of such structures.
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Owing to limited knowledge of the habitat use and diet of juvenile Arctic charr from the High Arctic, particularly young-of-the-year (YOY), we assembled data obtained from samples taken in and around Lake Hazen, Nunavut, Canada, to assess juvenile habitat use and feeding. Juvenile charr demonstrated a preference for stream environments, particularly those fed by warm upstream ponds. Charr occupying both stream and nearshore lake habitats were found to feed similarly, with chironomids occurring most frequently in diets. Some older stream-dwelling charr preyed on smaller, younger Arctic charr. Preferred stream occupancy is likely mediated by physical barriers created mainly by water velocity, and by distance from the lake, lake-ice dynamics, low water depth, and turbidity. Water velocities resulted in stream habitat segregation by size, with YOY mainly found in low-velocity pools and back eddies adjacent to stream banks, but not in water velocities >0.1 m/s. Greatest charr densities in streams were found in small, shallow, slow-flowing side channels, which are highly susceptible to drought. Under predicted climate change scenarios, streams fed by small ponds will be susceptible to intermittent flow conditions, which could result in increased competition among juvenile charr for the remaining stream habitats. In addition, glacier-fed streams are likely to experience increased flow conditions that will exacerbate physical barriers created by water velocity and further reduce the availability of preferred stream habitat.
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Includes bibliographical references.
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Includes sections on household hints, etiquette, needlework, home remedies, medicinal plants, diseases in children, first aid, and cake baking. Sample recipes: Common twist or cough candy, Crullers, Rich bride cake.