49 resultados para cluster analysis


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A global database containing 3365 occurrences, 821 species and 251 genera of the Capitanian (Late Guadalupian, Permian) brachiopod faunas from 24 stations has been analyzed by cluster analysis using the Jaccard and Otsuka coefficients and the probabilistic index of similarity, nonmetric multidimensional scaling and minimum spanning tree. Two supergroups, three groups and six subgroups are revealed and interpreted as representing, respectively, two biotic realms (the Palaeoequatorial and Gondwanan Realms), two regions and six provinces. An additional realm (the Boreal Realm), based on the fauna from Spitsbergen, also appears recognizable although it also shows considerable similarities with southwestern North America and the northern margin of Gondwana as revealed by the statistical analysis. The Palaeoequatorial Realm can be further subdivided into the North America Region and the Asian Tethyan Region. The six biotic provinces are the Cathaysian Province in the Palaeotethys and Mesotethys, the Greenland-Svalbard Province in the Arctic region, the Austrazean Province in eastern Australia and New Zealand, the Grandian Province in western North America and the two transitional zones (the Himalayan Province in the southern temperate zone and the Sino–Mongolian–Japanese Province in the northern temperate zone). Polynomial regression analysis and rarefaction analysis indicate that the generic diversities of brachiopod faunas during the Capitanian peaked in the Palaeoequatorial Cathaysian Province and the two transitional zones (Himalayan Province and Sino–Mongolian–Japanese Province), but fell dramatically in the polar regions. The generic diversity of the Palaeoequatorial Grandian Province is apparently lower than in the two transitional zones of temperate palaeolatitudes, suggesting that the generic diversity of Capitanian brachiopod faunas does not exhibit a strict negative correlation with palaeolatitudes. This in turn would suggest that biogeographical determinants (such as geographical barriers, inhabitable area and ocean currents) other than latitude-related temperature control may also have played an important role in the dispersal of some brachiopods and the characterization of some local provinces and high diversities. The Capitanian global brachiopod palaeobiogeography is generally comparable with those in the Wuchiapingian and Changhsingian, but with some notable differences. These include: (1) that the Grandian Province of the Capitanian in western North America vanished after the end-Guadalupian regression, (2) that the western Tethyan Province of the Lopingian could not be distinguished in the Capitanian, and (3) that the Austrazean Province was larger in area than either in the Wuchiapingian or in the Changhsingian.

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Purpose – The purpose of this study is to examine the effects of culture on accounting professionalism in 12 developing countries by applying Gray's 1988 model and Hofstede 1980 cultural study.
Design/methodology/approach – Connecting seven variables introduced within a testable model lead the finding to classify the twelve countries within a range from statutory control to professionalism. The data set was collected from 1996 to 2000 through different sources. Twelve developing countries have been chosen from the Middle East and South East Asia in this study and cluster analysis is used for analysing and classifying the countries.
Findings – The results show while the Gray's hypothesis of statutory control is positively confirmed for Iran, and moderately for Bangladesh, Jordan, Oman, and Qatar, it is negatively rejected for Pakistan, Turkey, Malaysia, and Indonesia.
Research limitations/implications – One limitation of this study is the improvised nature of the data set caused by the difficulty in collecting an extensive data set from developing countries.
Practical implications – The findings of the study provides a useful source of information about accounting authority in those developing countries in which improve the knowledge and literature about the accounting practice internationally.
Originality/value – The findings of the study are useful in harmonization process of the international accounting practices. Knowledge about important aspects of accounting setting of the countries is essential to realize the impediments of harmonization.

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Prior to this study the circumscription of the endangered black-eared miner (Manorina melanotis) and the common yellow-throated miner (Manorina flavigula) has been clouded by the existence of hybrid individuals. We examined the intra- and inter-specific phenotypic variation of the two taxa. All available museum specimens (n=138) and a sample of live individuals (n=83) were examined. Cluster analysis revealed a continuum of phenotypic traits now exists between the two taxa. However, further analysis revealed the black-eared miner and yellow-throated miner were separable on phenotypic characters prior to extensive modification of mallee habitat after 1950, suggesting the black-eared miner should be afforded full species status [contrary to Schodde and Mason, 1999. (Schodde, R., Mason, I.J., 1999. The Directory of Australian Birds: Passerines. CSIRO Wildlife and Ecology, Canberra]. Our study highlights the need to carefully examine, not only intraspecific phenoptyic variation within a taxon, but to also consider how such variation may be affected by hybridisation facilitated by human disturbance of habitat.


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In a period when tourism is contracting, and in a destination with an extensive range of visitor attractions, the importance of local residents visitation is accentuated. The aim of this study was to explore whether there are differences across segments of the local resident market in terms of their motives for engaging in leisure activities within the context of tourist attractions. This study was set within the context of Melbourne, Australia. Melbourne has changed in recent years in terms of the range of attractions available to residents. A sample of 1005 local residents was used as the basis of this study. Cluster analysis was used to segment the sample, based on the intended frequency of visitation to a set of attractions. The motives for engaging in leisure were then explored for each of the segments using Unger and Kernan's (1983) Subjective Leisure Scale (SLS), which encompasses six motivational domains namely intrinsic satisfaction, perceived freedom, arousal, mastery, involvement and spontaneity, was applied in this study of leisure activities was used as the basis of identifying the motives for visiting the attractions.

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The rating of refereed journals has become important for academics and institutions as well as for sport management as a field of study. This paper argues that the dearth of a rating system in sport management works against the best interests of the development of the field. This paper presents a rating scheme for sport management journals, which replicates an earlier study of marketing journals, using weighted multi-dimensional perceptual ratings (Polonsky & Whitelaw, 2006). Forty-five senior sport management academics evaluated 13 journals on four criteria: journal prestige, contribution to theory, contribution to practice and contribution to teaching. Using the weighted scores of the four criteria for each journal and a supporting cluster analysis, four categories of journals were identified. The results of this study will assist academics as they argue the case for the quality of journals in which they publish. Further it facilitates evaluation of sport management journals in relation to one another on the basis of their overall ranking and their scores on the four individual criteria.

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In Little Penguins Eudyptula minor there are no reliable plumage or body size differences that can be used visually to distinguish the sex of individuals. However, sexual dimorphism of morphometric measures has been noted, with males always being a little larger than females. In this study, differences between E. minor sexes at eight colonies in south-eastern Australia were determined statistically via discriminant function analysis (DFA) and through the utilization of DNA-based techniques developed for non-ratite birds. The DFA correctly determined gender in 91.1% of cases and molecular methods were 100% accurate. Our DFA success rate of classification is similar to that previously published for Little Penguins in Victoria. In this study statistically significant differences in mean bill depths and lengths were found between Little Penguin colonies at St Kilda, Phillip Island and Gabo Island, compared to colonies at Kangaroo Island, Granite Island, Middle Island and London Bridge. As birds in eastern populations (St Kilda, Phillip Island, Gabo Island) exhibit statistically significantly smaller beaks (bill depth and bill length), separate discriminant functions were investigated for each phenotypically distinct geo-spatial cohort. Interestingly, cluster analysis for bill length identified three groups: western (Kangaroo Island and Granite Island), eastern (St Kilda, Phillip Island and Middle Island) and the London Bridge Little Penguin colony, which constituted a separate group. We conclude that while there is a slight increase in DF power for colonies west of Cape Otway and for some specific colonies, colony-specific DFA is not required to identify the sex of Little Penguins in south-eastern Australia.

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This paper extends the journal ranking debate by developing weighted multi-dimensional perceptual rankings based on respondents' evaluation of a journals' prestige, contribution to theory, contribution to practice and contribution to teaching. Spearman correlations indicate that journal rankings based on each of the evaluative criteria are statistically significantly correlated for all pairs of criteria, other than teaching and theory. The multi-dimensional evaluation is also statistically significantly correlated to all individual criteria, other than the teaching dimension. A cluster analysis of the journals using the four evaluative criteria identified that there are three groupings of journals: A, B, and C. In most cases, A journals are evaluated as performing better than B journals on each of evaluative criteria other than for the contribution to teaching where there are no difference in perceptions between groups. B journals are viewed to perform better than C journals on prestige, contribution to practice and contribution to teaching, but not based on their prestige of weighted evaluation. This suggests that there are differences in how academics view each group of journals, although these differences do seem to vary based on the grouping being considered (i.e., A, B, or C).

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This paper seeks to develop groupings of journals (A, B, C) using multi-dimensional perceptual rankings, based on North American respondents’ evaluation of a journal’s prestige, contribution to theory, contribution to practice and contribution to teaching. Nonparametric comparisons of criterion mean values indicate that there are generally statistically significant correlations between criteria. Cluster analysis identifies A, B, and C 'categorisations' of journals are different in regards to all four evaluative criteria.

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The authors report the results of a journal rating survey assessing 14 publications dedicated to arts management and related topics. Establishing a rating scheme for journals is an important step in the professionalization of an academic field. The authors argue that the development of a rating system in arts management is in the best interests of the discipline. Academics used weighted multidimensional perceptual ratings to evaluate each journal’s prestige, contribution to theory, contribution to practice and contribution to teaching. Cluster analysis using these four criteria identified three classes of journals: A, B+ and B. The setting of standards serves to identify quality goals for academics and journal editors alike, thus enhancing the standing of arts management as a subdiscipline of management.

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Segmentation has been widely studied in tourism research e.g. Dolnicar (2004). Dawley (2006) points that commonly used segmentation variables such as demographics lead to identifiable segments which are not actionable while other useful approaches e.g. psychographics, are actionable but not identifiable. The objective of this paper is to develop a two-stage linkage approach to segmentation whereby cluster analysis using psychographic variables is conducted within demographic group. Demographic groups are selected based on propensity to travel. This research utilizes data generated from a cross-sectional self-completed survey of 49,105 Australian respondents on travel and tourism. The managerial usefulness of this segmentation is assessed. Clearly segments can be directly linked both demographically and psychographically.

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Previous research suggests that identifying specific subgroups amongst the population of adolescent sexual offenders may contribute to understanding the aetiology of their offending. Such knowledge may also help to improve the treatment outcomes for this group. The Millon Adolescent Clinical Inventory (MACI) profiles of 25 adolescent male sexual offenders aged 13 to 17 in a community-based treatment sample were analysed to determine if this measure could be used to identify different subtypes of offenders based on personality variables. Three groups were identified by cluster analysis: one group of antisocial and externalising types (n = 11), another group of withdrawn, socially inadequate types (n = 7) and a third group displaying few traits of clinically significant elevation (n = 7). Support was also shown for the hypothesis that adolescent sexual offenders exhibit personality profiles similar to those of delinquent non-sexual offenders. The observed typology suggests potentially different etiological pathways and different treatment needs.

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The Millon Adolescent Clinical Inventory (MACI) profiles of 82 adolescent male sexual offenders aged 13-19 in a community-based treatment sample were analysed to identify different subtypes of offender based on personality variables. Four groups were identified by cluster analysis: a withdrawn, socially inadequate type (n = 25); an antisocial and externalising type (n = 11); a conforming type (n = 20); and a passive-aggressive type (n = 26). Between-group comparisons showed that the proportion of adolescents reporting physical abuse by their parents was significantly different across the four groups. Subgroup membership was unrelated to victim age, victim gender, and offender history of sexual victimisation. Adolescents who had been victims of sexual abuse were significantly more likely to have had a male victim than those offenders without a history of sexual victimisation. The results of this study provide evidence for the heterogeneity of adolescent sexual offenders in terms of personality characteristics and psychopathology, while also suggesting potentially different aetiological pathways and different treatment needs.

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The objective of the work reported in this thesis was to design and implement an ecological effects environmental monitoring program which would: 1) Collect baseline biological information on sessile epibiotic fouling communities from an area adjacent to a petroleum refinery located on Corio Bay, Victoria, to allow comparison with results of future monitoring for the assessment of long term temporal water quality trends. 2) Detect and — if possible - estimate the magnitude of any influence on epibiotic fouling communities within the Corio Bay marine ecosystem attributable to operations at the Shell Petroleum Refinery. 3) Investigate the extent of thermal stratification and rate of dispersal of the petroleum refinery main cooling-water outfall plume (discharging up to 350,000 tonnes of warmed seawater per day), and its effect on epibiotic communities within the EPA-defined mixing zone. A major component of the work undertaken was the design and development of artificial-substrate biological sampling stations suitable for use under the conditions prevailing in Corio Bay, and the development of appropriate quantitative underwater photographic sampling techniques to fulfil the experimental criteria outlined above. Experimental and other constraints imposed on the design of the stations precluded the simple suspension of frames from jetties or pylons, a technique widely used in previous work of this type. Artificial substrate panels were deployed along three radial transects centred within and extending beyond the petroleum refinery main cooling-water mixing zone. Identical substrate panels were deployed at a number of control sites located throughout Corio Bay, each chosen for differences in their degree of exposure to such factors as water movement, depth, shipping traffic and/or comparable industrial activity. The rate of colonisation (space utilisation) and the development of epibiotic fouling communities on artificial substrate panels was monitored over two twelve-month sampling periods using quantitative underwater photographic sampling techniques. Sampling was conducted at 4-8 week intervals with the rate of panel colonisation and community structure determined via coverage measurements. Various species of marine algae, polychaete tubeworms, hydroids, barnacles, simple and colonial ascidians, sponges, bivalve molluscs and encrusting bryozoans were all detected growing on panels. Communities which established on panels within the cooling-water mixing-zone and those at control sites were compared using statistical procedures including agglomerative hierarchical cluster analysis. A photographic sample archive has been established to allow comparison with similar future studies.

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The plant pathogen, Phytophthora dnnamomi, is a cause of dieback disease observed in sclerophyll vegetation in Australia, The effects of P. dnnamomi on flora and fauna were studied at two locations in heathland vegetation near the coastal town of Anglesea, Victoria. The pathogen was isolated from soils beneath diseased heathland plants. The extent of diseased vegetation was assessed by the presence and absence of highly sensitive indicator species, Xanthorrhoea australis and hopogon ceratophyllus. The characteristics of heathland vegetation exhibiting dieback disease associated with the presence of P. dnnamomi were investigated. Plant species richness was similar between diseased and non-diseased areas however diseased areas were characterised by significant declines in the cover and frequency of susceptible species, increases in resistant species and increases in percent cover of open ground. Compared to non-diseased areas, diseased areas exhibited fewer shrub species and decreased shrub cover. The percentage cover and number of species of sedges, lilies and grasses were higher in diseased areas. Structural differences were significant between 0-0.6 m with decreased cover of vegetation in diseased areas. Differences in structure between diseased and non-diseased areas were not as great as expected due to increases in the cover of resistant species. A number of regenerating X australis were observed in post-disease areas. Cluster analysis of floristic data could clearly separate diseased and non-diseased trap stations. The population dynamics and habitat use of eight small mammal species present were compared in diseased and non-diseased areas using trapping and radio-tracking techniques. The number of small mammal species captured in post-disease areas was significantly lower than non-diseased areas. Mean captures of Antechinus stuartii and Rattus fiisdpes were significantly lower in diseased areas on Grid B. Mean captures of Rattus lutreolus were significantly lower in diseased areas on both study grids. Significant differences were not observed in every season over the two year study period. Radio tracking revealed more observations of Sminthopsis leucopus in non-diseased vegetation than in diseased. Cercartetus nanus was frequently observed to utilise the disease susceptible X. australis for nesting. At one location, the recovery of vegetation and small mammal communities in non-diseased and diseased vegetation after fuel reduction burning was monitored for three years post-fire. Return of plant species after fire in both disease classes were similar, reaching 75% of pre-fire richness after three years. Vegetation cover was slower to return after fire in diseased areas. Of the seven small mammal species captured pre-fire, five were regularly captured in the three years after fire. General linear model analysis revealed a significant influence of disease on capture rates for total small mammals before fire and a significant influence of fire on capture rates for total small mammals after fire. After three years, the influence of fire on capture rates was reduced no significant difference was detected between disease classes. Measurements of microclimate indicate that diseased, burnt heathland was likely to experience greater extremes of temperature and wind speed. Seeding of diseased heathland with X. australis resulted in the establishment of seedlings of this sensitive species. The reported distributions of the mamma] species in Victoria were analysed to determine which species were associated with the reported distribution of dieback disease. Twenty-two species have more than 20% of their known distribution in diseased areas. Five of these species, Pseudomys novaehollandiae, Pseudomys fumeust Pseudomys shortridgei, Potorous longipes and Petrogale pencillata are rare or endangered in Victoria. Four of the twenty-two species, Sminthopsis leucopus, Isoodon obesulus, Cercartetus nanus and Rottus lutreolus am observed in Victorian heathlands. Phytophthora cinnamomi changes both the structure and floristics of heathland vegetation in the eastern Qtway Ranges. Small mammals respond to these changes through decreased utilisation of diseased heathland. The pathogen threatens the diversity of species present and future research efforts should be directed towards limiting its spread and rehabilitating diseased areas.

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This thesis describes the research undertaken for a degree of Master of Science in a retrospective study of airborne remotely sensed data registered in 1990 and 1993, and field captured data of aquatic humus concentrations for ~ 45 lakes in Tasmania. The aim was to investigate and describe the relationship between the remotely sensed data and the field data and to test the hypothesis that the remotely sensed data would establish further evidence of a limnological corridor of change running north-west to south- east. The airborne remotely sensed data consisted of data captured by the CSIRO Ocean Colour Scanner (OCS) and a newly developed Canadian scanner, a compact airborne spectrographic imager (CASI). The thesis investigates the relationship between the two kinds of data sources. The remotely sensed data was collected with the OCS scanner in 1990 (during one day) and with both the OCS and the CASI in 1993 (during three days). The OCS scanner registers data in 9 wavelength bands between 380 nm and 960 nm with a 10-20 nm bandwidth, and the CASI in 288 wavelength bands between 379.57 nm and 893.5 nm (ie. spectral mode) with a spectral resolution of 2.5 nm. The remotely sensed data were extracted from the original tapes with the help of the CSIRO and supplied software and digital sample areas (band value means) for each lake were subsequently extracted for data manipulation and statistical analysis. Field data was captured concurrently with the remotely sensed data in 1993 by lake hopping using a light aircraft with floats. The field data used for analysis with the remotely sensed data were the laboratory determined g440 values from the 1993 water samples collated with g440 values determined from earlier years. No spectro-radiometric data of the lakes, data of incoming irradiance or ancillary climatic data were captured during the remote sensing missions. The sections of the background chapter in the thesis provide a background to the research both in regards to remote sensing of water quality and the relationship between remotely sensed spectral data and water quality parameters, as well as a description of the Tasmanian lakes flown. The lakes were divided into four groups based on results from previous studies and optical parameters, especially aquatic humus concentrations as measured from field captured data. The four groups consist of the ‘green” clear water lakes mostly situated on the Central Plateau, the ‘brown” highly dystrophic lakes in western Tasmania, the ‘corridor” lakes situated along a corridor of change lying approximately between the two lines denoting the Jurassic edge and 1200 mm isohyet, and the ‘eastern, turbid” lakes make up the fourth group. The analytical part of the research work was mostly concerned with manipulating and analysing the CASI data because of its higher spectral resolution. The research explores methods to apply corrections to this data to reduce the disturbing effects of varying illumination and atmospheric conditions. Three different methods were attempted. In the first method two different standardisation formulas are applied to the data as well as ‘day correction” factors calculated from data from one of the lakes, Lake Rolleston, which had data captured for all three days of the remote sensing operations. The standardisation formulas were also applied to the OCS data. In second method an attempt to reduce the effects of the atmosphere was performed using spectro-radiometric captured in 1988 for one of the lakes flown, Great Lake. All the lake sample data were time normalised using general irradiance data obtained from the University of Tasmania and the sky portion as calculated from Great Lake upwelling irradiance data was then subtracted. The last method involved using two different band ratios to eliminate atmospheric effects. Statistical analysis was applied to the data resulting from the three methods to try to describe the relationship between the remotely sensed data and the field captured data. Discriminant analysis, cluster analysis and factor analysis using principal component analysis (pea) were applied to the remotely sensed data and the field data. The factor scores resulting from the pca were regressed against the field collated data of g440 as were the values resulting from last method. The results from the statistical analysis of the data from the first method show that the lakes group well (100%) against the predetermined groups using discriminant analysis applied to the remotely sensed CASI data. Most variance in the data are contained in the first factor resulting from pca regardless of data manipulation method. Regression of the factor scores against g440 field data show a strong non- linear relationship and a one-sided linear regression test is therefore considered an inappropriate analysis method to describe the dataset relationships. The research has shown that with the available data, correction and analysis methods, and within the scope of the Masters study, it was not possible to establish the relationships between the remotely sensed data and the field measured parameters as hoped. The main reason for this was the failure to retrieve remotely sensed lake signatures adequately corrected for atmospheric noise for comparison with the field data. This in turn is a result of the lack of detailed ancillary information needed to apply available established methods for noise reduction - to apply these methods we require field spectroradiometric measurements and environmental information of the varying conditions both within the study area and within the time frame of capture of the remotely sensed data.