985 resultados para Revealed preference


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This paper introduces an incremental FP-Growth approach for Web content based data mining and its application in solving a real world problem The problem is solved in the following ways. Firstly, we obtain the semi-structured data from the Web pages of Chinese car market and structure them and save them in local database. Secondly, we use an incremental FP-Growth algorithm for mining association rules to discover Chinese consumers' car consumption preference. To find more general regularities, an attribute-oriented induction method is also utilized to find customer's consumption preference among a range of car categories. Experimental results have revealed some interesting consumption preferences that are useful for the decision makers to make the policy to encourage and guide car consumption. Although the current data we used may not be the best representative of the actual market in practice, it is still good enough for the decision making purpose in terms of reflecting the real situation of car consumption preference under the two assumptions in the context.

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When the average number of spam messages received is continually increasing exponentially, both the Internet service provider and the end user suffer. The lack of an efficient solution may threaten the usability of the email as a communication means. In this paper we present a filtering mechanism applying the idea of preference ranking. This filtering mechanism will distinguish spam emails from other email on the Internet. The preference ranking gives the similarity values for nominated emails and spam emails specified by users, so that the ISP/end users can deal with spam emails at filtering points. We designed three filtering points to classify nominated emails into spam email, unsure email and legitimate email. This filtering mechanism can be applied on both middleware and at the client-side. The experiments show that high precision, recall and TCR (total cost ratio) of spam emails can be predicted for the preference based filtering mechanisms.

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Lawulu fruit (Crysophylum roxberghi GDon) possess nutritional, medicinal and functional properties. However, it is less consumed due to its  characteristic off flavour. The present study was carried out to investigate the potential of utilizing lawulu fruit for isolation of pectin and to develop jam and fruit leather. Products were evaluated based on physico-chemical and sensory properties.

Pectin isolated fromf irm ripe lawuluf ruit using 0.1 M hydrochloric acid  followed by 96% ethanol precipitation yielded 7. 3% pectin on wet weight basis and 26.1% on dry weight basis. The isolated pectin contained 0.74% ash, 0.02% acetyl content and 7.85% methoxyl content with equivalent weight 993.5. These values were comparable with commercial high methoxyl pectin. In addition, Iawulu pectin at 1.5% concentration formed a gel within 12-14 min in the presence of 68% sucrose and 0.5% citric acid.

Jam was prepared by using Iawulu-pineapple ratio as 1:2, 1:1 and 2:1 respectively. The gel strength of jam (650 Brix and pH 3.1) at 0.35% commercial high methoxyl pectin was comparable with commercial mixed fruit jam. Sensory evaluation indicated a significant preference (p<.05) for jam containing lawulu-pineapple ratio of 1:2 and 1.1 respectively overthe ratio of 2:1. With increased lawulu percentage both yellowness and lightness of jam increased significantly (p<0.05).

Fruit leather was prepared by changing lawulu-pineapple ratio as 1:2, 1:1 and 2:1 respectively with 20% sucrose, 0.3% citric acid, 0.05% pectin and 100 ppm potassium metabisulphite followed by drying at 65±10C for 12-14 h. Sensory evaluation data revealed that changes in lawulu-pineapple ratio had no significant effect on taste, texture and overall quality of fruit leather.   However, significant preference (p<0.05) for colour was observed with increasing lawulu percentage. Both yellowness (b' value) and lightness (L'value) of fruit leather were sign[icantly increased (p<0.05) with increasing lawulu percentage.

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Heideggerian phenomenology is expounded here as a qualitative methodology of value in researching "how things really are" in organisational life. It is a methodology, and a philosophy, which recognises a priori the value ofthe subjective, lived experience of the informant, and the physical, sociological and psychological phenomena that come together to create their life-world. In this paper, the authors present cases where this methodology successfully revealed the respondents' reality. Stories about working in teams and being downsized are shared to demonstrate the ability of Heideggerian phenomenology to reveal how life really is in organisations.

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Forest management policy decisions are complex due to the multiple-use nature of goods and services from forests, difficulty in monetary valuation of ecological services and the involvement of a large number of stakeholders. Multi-attribute decision techniques can be used to synthesise stakeholder preferences related to regional forest planning because it can accommodate conflicting, multidimensional, incommensurable and incomparable objectives. The objective of this paper is to examine how the Analytical Hierarchy Process (AHP) can be used to incorporate stakeholder preferences in determining optimal forest land-use choices. The Australian Regional Forest Agreement Programme is taken as an illustrative case for the analysis. The results show that the AHP can formalise public participation in decision making and increase the transparency and the credibility of the process.

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Using an attitude-behaviour theory approach this study examined the direct and indirect influence of preference, life priority and time allocation on regular participation in leisure-time physical activity (LTPA). The crosssectional study used self-report questionnaires to collect data from a random sample of 250 people aged 19 to 87 years living in an Australian city. The findings suggest that people’s regular participation in LTPA is not directly influenced by their preference for it. Rather, making LTPA a high life priority and allocating time for LTPA are intervening factors that explain the relationship. The outcomes emphasise the importance of encouraging the formation of a preference for physical activity in young children. They suggest all levels of government and the leisure profession emphasise work/life balance by prioritising LTPA, educating people about time management and helping them to develop time management skills.

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Although 90% of passerine birds live in socially monogamous pair bonds, molecular studies have revealed that genetic polygamy occurs in 86% of surveyed passerines, because individuals engage in copulations outside the pair bond (extrapair copulations; EPCs). Most explanations for the occurrence of EPCs involve female gaining indirect benefits from the extrapair male. The sedge warbler is a socially monogamous species in which some offspring result from EPCs (8% in this study). Complex song is a sexually selected male trait used by females which select mates based on a variety of male qualities. We used microsatellite DNA profiling to detect extrapair young and assign paternity. ‘Good genes’ theory predicts that females should engage in EPCs with males of higher quality than their social mate, with resulting fitness benefits. Extrapair males had smaller song repertoires and smaller territories than the social mate. This apparent preference for small-repertoire males as extrapair mates conflicts with the predictions from previous studies of this species. Sudden cessation of song after pairing may mean that song cues are unavailable for later extrapair matings and females may switch to other cues. Such behaviour may lead to different patterns of female choice during social and extrapair mating in the sedge warbler. We conclude that multiple reasons underlie patterns of female choice in this species.

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The central bearded dragon (Pogona vitticeps) is a medium-sized lizard that is common in semiarid habitats in Australia and that potentially is at risk of fenitrothion exposure from use of the chemical in plague locust control. We examined the effects of single sublethal doses of this organophosphate (OP; low dose = 2.0 mg/kg; high dose = 20 mg/kg; control = vehicle alone) on lizard thermal preference, standard metabolic rate, and prey-capture ability. We also measured activities of plasma total cholinesterase (ChE) and acetylcholinesterase before and at 0, 2, 8, 24, 120, and 504 h after OP dosing. Predose plasma total ChE activity differed significantly between sexes and averaged 0.66 ± 0.06 and 0.45 ± 0.06 μmol/min/ml for males and females, respectively. Approximately 75% of total ChE activity was attributable to butyrylcholinesterase. Peak ChE inhibition reached 19% 2 h after OP ingestion in the low-dose group, and 68% 8 h after ingestion in high-dose animals. Neither OP doses significantly affected diurnal body temperature, standard metabolic rate, or feeding rate. Plasma total ChE levels remained substantially depressed up to 21 d after dosing in the high-dose group, making this species a useful long-term biomonitor of OP exposure in its habitat.

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Background – It is widely acknowledged that sodium is consumed in excess in most developed countries. Sodium (Na) consumption has been a target of public health interventions in recent years due to its link to numerous adverse health affects such as hypertension and cardiovascular disease. While much of the current research is directed at strategies to reduce sodium in foods and the diet, little is known about the factors which determine salt consumption and preference. Currently, there is no research relating NaCl taste sensitivity and liking of food, or if NaCl taste sensitivity may manifest in changes in BMI.
Objective – Establish whether a relationship exists between NaCl taste sensitivity, preference for salty foods and BMI.
Design – Taste sensitivity to NaCl was determined for 119 subjects (104 female) according to the procedure laid out by “ISO 3972:1991 – Method of investigating sensitivity of taste”. In a separate session subjects rated their liking of generic biscuit with 2 levels of added NaCl [low (2.9g/100g) & high (19.1g/100g)] using the 9-point hedonic scale. BMI was calculated from self reported height and weight data collected. Spearman’s rank order correlation was used to determine whether an association existed between NaCl taste sensitivity, preference for salty foods and BMI.
Outcomes – A significant positive correlation was found between BMI and NaCl taste sensitivity (r=0.204, p<0.05). In addition there was a significant positive correlation between BMI and liking of low NaCl biscuits (r=0.267, p<0.01). No significant associations were identified between the high NaCl cracker and NaCl taste sensitivity or BMI. A paired t-test showed there was no significant difference in liking of the low and commercial NaCl crackers (p=0.078).
Conclusion – This study revealed that individuals with a higher BMI have a greater liking of low NaCl biscuits, and this may be due to their increased NaCl taste sensitivity. The results suggest that NaCl taste sensitivity may be a factor in foods consumed by an individual which in turn may influence weight status.

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The present study investigated whether the most preferred balance between sweet and sour taste of children (n=50, 9.2±0.9 yrs of age) are related to their consumption of fruit. Taste preferences were measured with a rank-by-elimination procedure with seven sweet orangeades that differed in added citric acid (i.e. 0.009−0.065 M). Fruit consumption was assessed with a questionnaire that was completed by the children's parents. Results showed that boys' but not girls' most preferred balance between sweet and sour taste was positively correlated with their consumption of fruit: that is, the more added citric acid was preferred the more fruit was consumed. We conclude that preference for high concentrations of citric acid in a sweet context may be associated with the consumption of fruit in boys. In girls, the optimal balance between sweet and sour taste seems to be of less importance; their consumption of fruit may be more influenced by their parents, availability and health related motives.

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This study seeks to examine differences in travel preference, travel intention and destination choice behavior of an aggregated set of Australian travelers. Additionally the study seeks to relate income, age, gender, life cycle and life style of Australians to the preference, planning and choice of Asian and overseas destinations. A large representative sample of 49,000 Australian respondents is utilized. Binomial regression is used to profile travelers to Asia and overseas in general. Specific significant variables and differences are highlighted. There are consistent relationships between travel preference, planning and choice and the set of independent variables of income, life cycle and life style. Age nor gender are not consistently related to travel planning or travel choice. It is apparent that a combination of demographics, e.g. age, income and life cycle, combined with life style will provide a more valuable basis for segmentation of Asian and overseas travel markets. The study aims to profile potential Australian tourists thereby making a contribution to tourism knowledge and market segmentation practice.

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1. Understanding the structure of threatened populations, particularly those that exist in degraded or fragmented habitats is crucial for their effective management and conservation. Recently developed methods of individual-based analysis of genetic data provide an unprecedented opportunity to understand the relationships amongst fragmented populations.

2. In the present study, population structure of an important cyprinid species (Tor douronensis), which is indigenous to Sarawak, Malaysia, is investigated as part of an ongoing conservation effort to restore threatened wild populations of the species. The population structure inferred using data from seven autosomal microsatellite loci was generally consistent with geography and habitat fragmentation.

3. The results indicate that there are two well-defined clusters of T. douronensis in Sarawak, namely the 'northeastern' and the 'southwestern' clusters. In addition, a further subdivision was observed in each of the clusters distributed between river systems. Low levels of gene flow were also observed and migrants between habitat fragments were identified, possibly resulting from human-mediated translocations.

4. Implications of the findings for management and conservation of T. douronensis are discussed.

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Aquaculture of the striped catfish, Pangasianodon hypophthalmus (Sauvage 1878), in Vietnam has become one of the fastest growing primary food production sectors in the world. Although a demand on quantity of fingerlings is currently reached, it is likely that the long term quality of the stocks may be uncertain due to lacking of genetic broodstock management measures. The present study employed five microsatellite loci to investigate levels of genetic variation of the stripped catfish of the current wild stocks as well as of the selected hatcheries in Vietnam. The study included four hatchery populations and two wild populations spawned in 2005 in the Mekong and Bassac Rivers, and one wild population (spawned in 2006) in the Bassac River. The results showed no genetic differentiation among populations as revealed by FST and a model-based clustering method. AMOVA also showed no genetic differentiation between pooled wild and pooled hatchery populations while variation within groups was significant. Genetic variation of wild (mean number of alleles per locus, A = 4.80–6.20; allelic richness, Ar = 4.54–5.06; mean effective number of alleles per locus, Ae = 2.86–3.20; observed heterozygosity, Ho = 0.62–0.65; expected heterozygosity, He = 0.62–0.64) and hatchery populations (A = 4.60–5.20; Ar = 4.10–4.83; Ae = 2.80–3.11; Ho = 0.61–0.66; He = 0.61–0.64) were not statistically different. There were no evidences for recent genetic bottleneck in all populations. Therefore it is implied that the hatchery stocks of striped catfish in Vietnam were founded from sufficient numbers of brooders and current population size is large. The domestication process is in an early stage.