Home About us Contact
|
Home About us Contact | ||
|
|
||
Dissimilarity
Kinds of Dissimilarity Selected AbstractsSpatial autocorrelation of assemblages of benthic invertebrates and its relationship to environmental factors in two upland rivers in southeastern AustraliaDIVERSITY AND DISTRIBUTIONS, Issue 5 2005Natalie J. Lloyd ABSTRACT The nature of spatial autocorrelation of biota may reveal much about underlying ecological and biological factors responsible for producing those patterns, especially dispersal processes (drift, adult flight, etc.). We report here on assemblage-level autocorrelation in the benthic-invertebrate assemblages (retained in sieves of 300 µm mesh) of riffles in two adjacent, relatively pristine rivers in southeastern Victoria, Australia (40-km reaches of the Wellington and Wonnangatta Rivers). These are related to patterns of autocorrelation in physical and catchment conditions (,environmental variables') in the vicinity of the sampling points. Both the invertebrate assemblages and environmental variables were autocorrelated at small scales (= 8 km) in the Wellington River in one of the sampling years (1996). Dissimilarities of invertebrate assemblages were correlated with dissimilarities of environmental variables in both sampling years (1996 and 1997) in that river. Environmental variables were autocorrelated in the Wonnangatta River, but this was not expressed as autocorrelation in the assemblages of invertebrates, which were not autocorrelated at any scale studied. Individual environmental variables showed different spatial patterns between the two rivers. These results suggest that individual rivers have their own idiosyncratic patterns and one cannot assume that even similar, geographically adjacent rivers will have the same patterns, which is a difficulty for ecological assessment and restoration. [source] Tax-induced Dissimilarities Between Domestic and Foreign Mutual Funds in ItalyECONOMIC NOTES, Issue 2 2006Roberto Savona Using data from Italy over the period 1998,2002, this study investigates whether tax effects can account for differences in return patterns between domestic and foreign mutual funds, and if this dissimilarity translates into performance. The paper presents evidence that much of the difference between domestic and foreign funds is explained by the different tax systems. The asymmetry between the two groups, due to the fact that domestic funds are obliged to pay taxes on a daily basis while foreign funds are taxed when capital gains are collected, also affects performance. We prove that comparing pre-tax returns, Italian funds are virtually indistinguishable from their foreign counterparts in terms of risk-adjusted returns, while when comparing after-tax returns, foreign funds outperform. [source] Localization of dihalogenated phenols in vesicle systems determined by contrast variation X-ray scatteringJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Zoltán Varga Localization of 2,4-dichloro- and 2,4-dibromophenol in multilamellar vesicles in a 1/1 dihalogenated phenol/lipid molar ratio was investigated by classical contrast variation X-ray scattering using the isomorphous replacement method. The results were compared with those obtained by anomalous small-angle X-ray scattering from a vesicle system doped with 2,4-dibromophenol. Dissimilarities in the results of the two methods are discussed, taking into account the advantages and disadvantages of both techniques in studying multilamellar systems. [source] Quantifying successional changes in response to forest disturbancesAPPLIED VEGETATION SCIENCE, Issue 2 2008Trent D. Penman Question: Can dissimilarity measures of individual plots be used to forecast the driving factors among various anthropogenic disturbances influencing understorey successional changes? Location: Yambulla State Forest, south-eastern Australia (37°14'S, 149°38'E). Methods: Assessments of understorey vegetation communities were taken prior to anthropogenic disturbances and at three subsequent time periods representing a period of 15 years post-disturbance. Dissimilarities were calculated from the original assessment and modelled in a Bayesian framework to examine the influence of logging, number of prescribed burns and time. Results: All sites underwent significant changes over time independently of the imposed management regimes. Logging resulted in an immediate change in vegetation assemblage which decreased in the subsequent assessments. The number of prescribed fires brought greater change in the shrub vegetation assemblages, but less change in the ground species vegetation assemblages. Conclusions: The anthropogenic disturbances did have some role in the changes of vegetation assemblages but these were minimal. The ongoing changes appear to be a natural response to the last wildfire, which passed through the study area in 1973 (13 years prior to the study). Forest management practices should consider the influence of wildfire succession when planning for the conservation of biodiversity. [source] Sex Composition, Masculinity Stereotype Dissimilarity and the Quality of Men's Workplace Social RelationsGENDER, WORK & ORGANISATION, Issue 5 2003Sharon R. Bird Previous research suggests that the quality of men's work group social relations varies depending on the sex composition of the work unit. Previous studies also suggest that men derive different benefits from working with other men than with women and that the higher status associated with men and masculinity advantages men in their relations with women workers. Previous sex composition studies tell us little, however, about the extent to which the quality of men's work group social relations with women and other men depends on how well a man fits dominant masculinity stereotypes. Drawing on sex composition and gender constructionist approaches to gender and work I investigate in this study the effects of men's individual similarity to masculinity stereotypes on the affective quality of their social relations with coworkers, given the sex composition of their work groups. The data for this study consist of male, mostly white, non-faculty employees of a public university in the northwest United States. I discuss my results in terms of both individual outcomes and implications for understanding sex and gender inequalities in work organizations. [source] Species Composition of Neotropical Understory Bird Communities: Local Versus Regional Perspectives Based on Capture DataBIOTROPICA, Issue 1 2009John G. Blake ABSTRACT Species richness and composition of bird assemblages found in the understory of undisturbed Neotropical forests vary at local and regional scales but the extent of that variation has not been well documented. Yet, such variation can be important for understanding patterns of diversity and for conservation. Here, we use capture data from two ca 100-ha study plots (sampled from March 2001 through March 2005) to compare understory assemblages at a local scale; nets on the plots were separated by approximately 1.7 km at the closest point. A total of 157 species (133 per plot) was represented in 6023 captures of 4001 individuals. After eliminating species not likely to be well-sampled with nets, there were 122 species total with 110 and 113 on the two plots, respectively. Species-accumulation curves and abundance-rank relationships were almost identical on both plots. Capture rates were high (53 and 56 birds captured per 100 mist-net-hours, mnh) on both plots. Distributions of species and individuals among families and genera were similar on the two plots but numbers of captures of some common species differed between plots in response to small-scale variation in environmental features. Indicator-species analyses selected seven species as more characteristic of one plot and nine as more characteristic of the other. At the regional level, understory assemblages were most similar to a site in Peru but differed from sites in Brazil, Venezuela, and, especially, Costa Rica. Dissimilarity in species richness per family was related to geographic distance only when Costa Rica was included in the analysis. RESUMEN La riqueza de especies y la composición de ensambles de aves de sotobosque en bosques neotropicales varían a escala local y regional, pero el grado de variación no ha sido bien documentado. Sin embargo, esta variación puede ser importante para entender los patrones de diversidad y para conservación. En este trabajo usamos datos de captura de dos parcelas de ca 100-ha (muestreados entre Marzo 2001 y Marzo 2005) para comparar los ensambles de aves de sotobosque a escala local; las redes en las dos parcelas estuvieron ubicadas a una distancia mínima aproximada de 1.7 km. Un total de 157 especies (133 por parcela) estuvieron representadas por 6023 capturas correspondientes a 4001 individuos. Una vez eliminadas aquellas especies que no son factibles de ser muestreadas adecuadamente con redes, el total de especies fue de 122, con 110 y 113 en cada una de los parcelas, respectivamente. Las curvas de acumulación de especies y las relaciones abundancia-rango fueron casi idénticas en ambas parcelas. Las tasas de captura fueron altas (53 y 56 aves capturadas por 100 horas red). La distribución de especies e individuos entre familias y géneros fueron similares en las dos parcelas, pero los números de captura de algunas especies comunes difirieron entre las parcelas en respuesta a la variación de características ambientales a pequeña escala. Los análisis de especies indicadoras seleccionaron siete especies como las más características de una de las parcelas y nueve como las más características de la otra. A nivel regional los ensambles de aves de sotobosque fueron más similares a aquellos presentes en un sitio en Perú, pero fueron diferentes a los presentes en sitios de Brasil, Venezuela y especialmente Costa Rica. La diferencia en riqueza de especies por familia estuvo relacionada con la distancia geográfica sólo cuando Costa Rica fue incluida en el análisis. [source] Organizational-Level Gender Dissimilarity and Employee CommitmentBRITISH JOURNAL OF INDUSTRIAL RELATIONS, Issue 4 2007Hyun-Jung Lee This study explores the extent to which gender dissimilarity in the workplace affects employees' commitment to their organization, using data from the British (1998) Workplace Employee Relations Survey. The results showed that the effects of organizational-level gender dissimilarity on organizational commitment were more complex than has commonly been assumed in the literature. The relationship between organizational-level gender dissimilarity and employee commitment was U-shaped for women whereas it was not significant for men. The relationship was moderated by the respondents' status as measured by their level of pay. For men, the relationship between gender dissimilarity and commitment was negative for high-paid individuals but not for low-paid ones, while for women the U-shaped relationship was weaker for high-paid individuals than for low-paid individuals. [source] Splinting duration and periodontal outcomes for replanted avulsed teeth: a systematic reviewDENTAL TRAUMATOLOGY, Issue 2 2009Susan Elisabeth Hinckfuss The principles of evidence-based dentistry can be used to assess whether these guidelines are based on currently-available evidence. A qualitative systematic review was conducted of relevant clinical literature to examine the evidence on splinting duration and periodontal healing outcomes. The review was constrained markedly by small sample sizes, retrospective nature of clinical audits, dissimilarities of selected studies in their design, methodology and observation periods, and lack of uniformity in terminology for outcomes. A total of 138 replanted avulsed permanent teeth pooled from four papers each reporting both short-term splinting (14 days or less) and long-term splinting (over 14 days) in accord with current clinical guidelines, were studied. The evidence for an association between short-term splinting and an increased likelihood of functional periodontal healing, acceptable healing, or decreased development of replacement resorption, appears inconclusive. The study found no evidence to contraindicate the current guidelines and suggests that the likelihood of successful periodontal healing after replantation is unaffected by splinting duration. Pending future research to the contrary, it is recommended that dentists continue to use the currently-recommended splinting periods when replanting avulsed permanent teeth. [source] Macroscopic Classificatrion of Early Colorectal Carcinoma: A Comparison Between Japan and ChinaDIGESTIVE ENDOSCOPY, Issue 4 2000Fang-yu Wang Background: To clarify the similarities and dissimilarities in the macroscopic classification criteria for early colorectal carcinoma (CRC) between Japan and China. Methods: Six early CRC cases were included in this study. Eleven Japanese and Chinese endoscopists were asked to review the colonoscopic pictures of these cases, including before and after indigocarmine spraying. After viewing the pictures, all the endoscopists individually made their classificatory diagnoses of these cases and indicated the findings on which they based each diagnosis. Results: Some lesions diagnosed by Japanese endoscopists as IIa or IIa + IIc, might be classified as Is or Isp by Chinese endoscopists. For superficial lesions consisting of elevation with central depression, IIa + depression, IIa + IIc or IIc + IIa were classified according to the ratio of elevated area/depressed area. However, international as well as interobserver differences still existed in the classification of such lesions. In addition, most Chinese endoscopists overlooked the slightly depressed part on the top of a protruded lesion. Conclusion: Discrepancies on macroscopic classification for early CRC do exist between Japanese and Chinese endoscopists, which were found not only in terminology, but also in recognition of some lesions. In order to develop a universal macroscopic classification, there is a great need for international communication and cooperation. [source] Spatial autocorrelation of assemblages of benthic invertebrates and its relationship to environmental factors in two upland rivers in southeastern AustraliaDIVERSITY AND DISTRIBUTIONS, Issue 5 2005Natalie J. Lloyd ABSTRACT The nature of spatial autocorrelation of biota may reveal much about underlying ecological and biological factors responsible for producing those patterns, especially dispersal processes (drift, adult flight, etc.). We report here on assemblage-level autocorrelation in the benthic-invertebrate assemblages (retained in sieves of 300 µm mesh) of riffles in two adjacent, relatively pristine rivers in southeastern Victoria, Australia (40-km reaches of the Wellington and Wonnangatta Rivers). These are related to patterns of autocorrelation in physical and catchment conditions (,environmental variables') in the vicinity of the sampling points. Both the invertebrate assemblages and environmental variables were autocorrelated at small scales (= 8 km) in the Wellington River in one of the sampling years (1996). Dissimilarities of invertebrate assemblages were correlated with dissimilarities of environmental variables in both sampling years (1996 and 1997) in that river. Environmental variables were autocorrelated in the Wonnangatta River, but this was not expressed as autocorrelation in the assemblages of invertebrates, which were not autocorrelated at any scale studied. Individual environmental variables showed different spatial patterns between the two rivers. These results suggest that individual rivers have their own idiosyncratic patterns and one cannot assume that even similar, geographically adjacent rivers will have the same patterns, which is a difficulty for ecological assessment and restoration. [source] Comparative phylogeography of salmonid fishes (Salmonidae) reveals late to post-Pleistocene exchange between three now-disjunct river basins in SiberiaDIVERSITY AND DISTRIBUTIONS, Issue 4 2003E. Froufe Abstract. We use a comparative phylogeographical framework to evaluate the hypothesis of hydrological exchange during the Pleistocene among the now disjunct Lena, Amur, and Enisei basins in Siberia, and to provide evidence on the causal mechanism of their present day faunal dissimilarities. Approximately 600 bases of the mitochondrial control region were sequenced in five distinct lineages among three genera of salmonid fishes, Hucho, Brachymystax and Thymallus. All three basins were fixed for divergent (2,5.4%) lineages of Thymallus whereas a single shared haplotype was present in all three basins for Hucho taimen (Pallas, 1773) and one shared haplotype between the Lena and Amur basins out of a total of five for blunt-snouted and one out of five for sharp-snouted Brachymystax lenok (Pallas, 1773). For both blunt- and sharp-snouted lenok the haplotypes found within each basin did not form clades, so no relationship between genotypes and geographical occurrence was found. Our data support relatively recent hydrological mixing of the major river drainage systems in eastern and far-eastern Siberia, congruent with the hypothesis of large-scale palaeo-hydrological exchange stemming from glacial advance, retreat and melting during Pleistocene climate fluctuations. Furthermore, these results in conjunction with a comparison of overall faunal composition suggest that environmental differences rather than historical contingency may be responsible for the faunal dissimilarities of the Amur, Lena, and Enisei river basins. [source] Differences in Echocardiographic Assessment with Standard Doppler and Tissue Doppler Imaging of Left Ventricular Filling Pressure in Idiopathic and Ischemic Dilated CardiomyopathyECHOCARDIOGRAPHY, Issue 7 2008Pierluigi Costanzo M.D. Background: In idiopathic and ischemic dilated cardiomyopathy (DCM) there are differences in left atrial and ventricular relaxation. We assessed the hypothesis of an influence of these dissimilarities in assessing left ventricular filling pressure (LVFP) in these two DCMs by standard Doppler and tissue Doppler imaging. In particular, we focused on early transmitral flow to early diastolic motion velocity of mitral annulus ratio (E/Ea), useful to estimate normal or elevated LVFP. However, when found in intermediate range (8,15), its role is unclear. Methods and Results: We evaluated 26 patients with ischemic and 21 patients with idiopathic DCM. To validate the echocardiographic estimation of LVFP, a sample (12 patients) underwent LVFP assessment by catheterization. In idiopathic DCM, E/Ea directly related to duration of retrograde pulmonary venous flow (ARd) (r = 0.66 P = 0001). In ischemic DCM E/Ea inversely related only to systolic to diastolic velocity ratio of pulmonary venous flow (S/D) (r =,0.56 P = 0002). After a mean follow up of 6 months, by a second echocardiogram we observed a direct relation between E/Ea and ARd percentage variation (r = 0.52 P = 0.02) in idiopathic DCM group, whereas in the ischemic DCM group there was an inverse relation between E/Ea and S/D percentage variation (r =,0.59 P = 0.02).Conclusions: In conclusion, ARd in idiopathic and S/D in ischemic DCM might be used as specific additional information to estimate LVFP when E/Ea falls within intermediate range. [source] Comparison of three expert elicitation methods for logistic regression on predicting the presence of the threatened brush-tailed rock-wallaby Petrogale penicillataENVIRONMETRICS, Issue 4 2009Rebecca A. O'Leary Abstract Numerous expert elicitation methods have been suggested for generalised linear models (GLMs). This paper compares three relatively new approaches to eliciting expert knowledge in a form suitable for Bayesian logistic regression. These methods were trialled on two experts in order to model the habitat suitability of the threatened Australian brush-tailed rock-wallaby (Petrogale penicillata). The first elicitation approach is a geographically assisted indirect predictive method with a geographic information system (GIS) interface. The second approach is a predictive indirect method which uses an interactive graphical tool. The third method uses a questionnaire to elicit expert knowledge directly about the impact of a habitat variable on the response. Two variables (slope and aspect) are used to examine prior and posterior distributions of the three methods. The results indicate that there are some similarities and dissimilarities between the expert informed priors of the two experts formulated from the different approaches. The choice of elicitation method depends on the statistical knowledge of the expert, their mapping skills, time constraints, accessibility to experts and funding available. This trial reveals that expert knowledge can be important when modelling rare event data, such as threatened species, because experts can provide additional information that may not be represented in the dataset. However care must be taken with the way in which this information is elicited and formulated. Copyright © 2008 John Wiley & Sons, Ltd. [source] ,Seek and ye shall find': antecedents of assimilation and contrast in social comparisonEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 5 2001Thomas Mussweiler Based on a Selective Accessibility (SA) model of comparison consequences, it is suggested that the self-evaluative effects of social comparisons depend on the nature of the hypothesis that is tested as a starting-point of the comparison process. If judges test the hypothesis that they are similar to the standard, then standard-consistent self-knowledge is rendered accessible so that self-evaluations are assimilated towards the standard. If judges test the hypothesis that they are dissimilar from the standard, however, standard-inconsistent self-knowledge is made accessible so that self-evaluations are contrasted away from the standard. These predictions are tested by inducing participants to test for similarity versus dissimilarity to the standard via a procedural priming manipulation. Consistent with the SA model, assimilation occurs if participants are procedurally primed to focus on similarities to the standard, whereas contrast results if they are primed to focus on dissimilarities. These findings suggest that similarity versus dissimilarity testing is a crucial determinant of assimilation versus contrast. It is proposed that distinguishing between these two alternative hypotheses may provide an integrative framework for an understanding of the self-evaluative consequences of social comparisons. Copyright © 2001 John Wiley & Sons, Ltd. [source] Small mammal (rodents and lagomorphs) European biogeography from the Late Oligocene to the mid PlioceneGLOBAL ECOLOGY, Issue 4 2007Olivier Maridet ABSTRACT Aim, To analyse the fossil species assemblages of rodents and lagomorphs from the European Neogene in order to assess what factors control small mammal biogeography at a deep-time evolutionary time-scale. Location, Western Europe: 626 fossil-bearing localities located within 31 regions and distributed among 18 successive biochronological units ranging from c. 27 Ma (million years ago; Late Oligocene) to c. 3 Ma (mid Pliocene). Methods, Taxonomically homogenized pooled regional assemblages are compared using the Raup and Crick index of faunal similarity; then, the inferred similarity matrices are visualized as neighbour-joining trees and by projecting the statistically significant interregional similarities and dissimilarities onto palaeogeographical maps. The inferred biogeographical patterns are analysed and discussed in the light of known palaeogeographical and palaeoclimatic events. Results, Successive time intervals with distinct biogeographical contexts are identified. Prior to c. 18 Ma (Late Oligocene and Early Miocene), a relative faunal homogeneity (high interregional connectivity) is observed all over Europe, a time when major geographical barriers and a weak climatic gradient are known. Then, from the beginning of the Middle Miocene onwards, the biogeography is marked by a significant decrease in interregional faunal affinities which matches a drastic global climatic degradation and leads, in the Late Miocene (c. 11 Ma), to a marked latitudinal pattern of small mammal distribution. In spite of a short rehomogenization around the Miocene/Pliocene boundary (6,4 Ma), the biogeography of small mammals in the mid Pliocene (c. 3 Ma) finally closely reflects the extant situation. Main conclusions, The resulting biogeographical evolutionary scheme indicates that the extant endemic situation has deep historical roots corresponding to global tectonic and climatic events acting as primary drivers of long-term changes. The correlation of biogeographical events with climatic changes emphasizes the prevalent role of the climate over geography in generating heterogeneous biogeographical patterns at the continental scale. [source] Fish community comparisons along environmental gradients in lakes of France and north-east USAGLOBAL ECOLOGY, Issue 3 2007Pascal Irz ABSTRACT Aim, To assess whether eight traits of fish communities (species richness, three reproductive traits and four trophic traits) respond similarly to environmental gradients, and consequently display convergence between the lakes of France and north-east USA (NEUSA). Location, 75 French and 168 north-east USA lakes. Methods, The data encompass fish surveys, the assignment of species into reproductive and trophic guilds, and environmental variables characterizing the lakes and their catchments. The analytical procedure was adapted from the recommendations of Schluter (1986) [Ecology, 67, 1073,1085]. Results, The comparison of the regional pools of lacustrine fishes indicated that NEUSA was about twice as speciose as France, mostly due to higher species turnover across lakes, although NEUSA lakes were consistently about 20% more speciose than French lakes for a given surface area. Warmer environments were consistently inhabited by a higher proportion of phytophilous and guarder species than were colder lakes. Hence there was convergence in community reproductive traits. Conversely, there was no evidence of convergence in the trophic structure of lacustrine fish communities between regions. Main conclusions, The influence of temperature on the availability and quality of spawning substrates appears to be a major constraint on present-day lacustrine fish communities. In parallel, phylogenetic constraints, past events such as the diversification of the North American fish fauna, and selective extinctions during Pleistocene glaciations and subsequent recolonizations contribute to explaining the dissimilarities between the communities of the two regions and differences in their relationship to the environment. [source] We are all different: insights from osteoporosis research in AsiaINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 4 2008Swan Sim YEAP Abstract Osteoporosis only became a ,disease' entity in the 20th century. After the initial observations and definitions of osteoporosis based on Caucasian populations, systematic research in Asian populations started in the 1980s. Significant variations between different ethnic groups with respect to the rate of osteoporotic fractures, bone mineral density and disease risk factors emerged from the data; this article highlights some of the earlier important findings and the dissimilarities. Osteoporosis is therefore not a homogeneous disease across the world. [source] Conceptualizing Religion and Spirituality: Points of Commonality, Points of DepartureJOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 1 2000Peter C. Hill Psychologists' emerging interest in spirituality and religion as well as the relevance of each phenomenon to issues of psychological importance requires an understanding of the fundamental characteristics of each construct. On the basis of both historical considerations and a limited but growing empirical literature, we caution against viewing spirituality and religiousness as incompatible and suggest that the common tendency to polarize the terms simply as individual vs. institutional or ,good, vs. ,bad, is not fruitful for future research. Also cautioning against the use of restrictive, narrow definitions or overly broad definitions that can rob either construct of its distinctive characteristics, we propose a set of criteria that recognizes the constructs' conceptual similarities and dissimilarities. Rather than trying to force new and likely unsuccessful definitions, we offer these criteria as benchmarks for judging the value of existing definitions. [source] The ED strategy: how species-level surrogates indicate general biodiversity patterns through an ,environmental diversity' perspectiveJOURNAL OF BIOGEOGRAPHY, Issue 8 2004D. P. Faith Abstract Biodiversity assessment requires that we use surrogate information in practice to indicate more general biodiversity patterns. ,ED' refers to a surrogates framework that can link species data and environmental information based on a robust relationship of compositional dissimilarities to ordinations that indicate underlying environmental variation. In an example analysis of species and environmental data from Panama, the environmental and spatial variables that correlate with an hybrid multi-dimensional scaling ordination were able to explain 83% of the variation in the corresponding Bray Curtis dissimilarities. The assumptions of ED also provide the rationale for its use of p-median optimization criteria to measure biodiversity patterns among sites in a region. M.B. Araújo, P.J. Densham & P.H. Williams (2004, Journal of Biogeography31, 1) have re-named ED as ,AD' in their evaluation of the surrogacy value of ED based on European species data. Because lessons from previous work on ED options consequently may have been neglected, we use a corroboration framework to investigate the evidence and ,background knowledge' presented in their evaluations of ED. Investigations focus on the possibility that their weak corroboration of ED surrogacy (non-significance of target species recovery relative to a null model) may be a consequence of Araújo et al.'s use of particular evidence and randomizations. We illustrate how their use of discrete ED, and not the recommended continuous ED, may have produced unnecessarily poor species recovery values. Further, possible poor optimization of their MDS ordinations, due to small numbers of simulations and/or low resolution of stress values appears to have provided a possible poor basis for ED application and, consequently, may have unnecessarily favoured non-corroboration results. Consideration of Araújo et al.'s randomizations suggests that acknowledged sampling biases in the European data have not only artefactually promoted the non-significance of ED recovery values, but also artefactually elevated the significance of competing species surrogates recovery values. We conclude that little credence should be given to the comparisons of ED and species-based complementarity sets presented in M.B. Araújo, P.J. Densham & P.H. Williams (2004, Journal of Biogeography31, 1), unless the factors outlined here can be analysed for their effects on results. We discuss the lessons concerning surrogates evaluation emerging from our investigations, calling for better provision in such studies of the background information that can allow (i) critical examination of evidence (both at the initial corroboration and re-evaluation stages), and (ii) greater synthesis of lessons about the pitfalls of different forms of evidence in different contexts. [source] A typology of motor vehicle consumers using motives for leasing versus financingJOURNAL OF CONSUMER BEHAVIOUR, Issue 4 2006Philip J. Trocchia Previous consumer research suggests that individuals who finance high-cost items tend to differ from those who lease the same items. Some differences are economic, such as income and wealth, while other dissimilarities involve non-economic issues such as personal preferences. We employ non-hierarchical cluster analysis to create consumer segments of motor vehicle lessees and financers based on motives for leasing versus financing and demographics. Five segments were uncovered. Lessees predominate in two categories: budget gourmets and automotive hedonists. Another two categories, utility seekers and basic transportation seekers, are mainly comprised of financers. The final group, mature luxury seekers, consists of a roughly equal mix of lessees and financers. Differences between the segments are addressed here, along with a discussion of findings and implications. Copyright © 2006 John Wiley & Sons, Ltd. [source] Differential Growth Inhibition of Diaporthe and Phomopsis Isolates by the Metabolic Activity of Five ActinomycetesJOURNAL OF PHYTOPATHOLOGY, Issue 5 2000M. Munta ñola-Cvetkovic Fifty-five cultures derived from Diaporthe perithecia and Phomopsis pycnidia found on diverse host plant species collected at different times and sites in Vojvodina, Yugoslavia, showed distinguishing quantitative reactions to the fungistatic activity of five actinomycetes obtained as fortuitous laboratory contaminants coming from field material. Streptomyces albidoflavus, S. albus, S. diastaticus, Streptomyces sp., and Streptoverticillium sp. could be ranked by their growth-inhibitory potential, with S. albus showing the strongest, and Streptomyces sp. the lowest. The responses of the fungi varied depending on the tested actinomycetes, but two major groups could be distinguished: A, which encompased the isolates that were less affected by the proximity of the actinomycetes; and B, with those which exhibited high sensitivity in all the experiments. Group A was typically represented by Diaporthe arctii, Phomopsis longicolla, and the Phomopsis type-1 cultures from Xanthiumitalicum; group B was typically represented by Diaporthe/Phomopsis helianthi,Phomopsis type-2 cultures from X. italicum, and isolates from Lactuca serriola. The results obtained underscore the dissimilarities between D. arctii and D. helianthi, and corroborate the value of the physiological aspects of congeneric isolates in considering taxonomic problems in the coelomicete genus Phomopsis. Zusammenfassung Aus Diaporthe -Perithecien und Phomopsis -Pyknidien von verschiedenen Wirtspflanzenarten, die zu unterschiedlichen Zeitpunkten und an verschiedenen Orten in der jugoslawischen Vojvodina gesammelt worden waren, wurden 55 Kulturen gewonnen. Die Isolate zeigten charakteristische quantitative Reaktionen auf die fungistatische Aktivität von fünf Actinomyceten, die im Labor als Zufallskontaminanten auftraten und von Feldmaterial stammten. Streptomyces albidoflavus, S. albus, S. diastaticus, Streptomyces sp. und Streptoverticillium sp. konntenihrem wachstumshemmenden Potential entsprechend geordnet werden, wobei S. albus die stärkste und Streptomyces sp. die niedrigste Hemmung zeigte. Die Reaktionen der Pilze variierten in Abhängigkeit von den getesteten Actinomyceten, doch zwei Hauptgruppen lie,en sich unterscheiden: Gruppe A umf,te die Isolate, die von der Nähe der Actinomyceten weniger gehemmt wurden, und Gruppe B die Isolate, die bei allen Versuchen eine hohe Sensitivität zeigten. Typische Vertreter der Gruppe A waren Diaporthe arctii, Phomopsis longicolla sowie die von Xanthium italicum stammenden Phomopsis -Kulturen vom Typ 1. Typische Repräsentanten der Gruppe B waren Diaporthe/Phomopsis helianthi, die von X. italicum stammenden Phomopsis -Kulturen vom Typ 2 sowie von Lactuca serriola stammende Isolate. Die Ergebnisse verdeutlichen die Unterschiede zwischen D. arctii und D. helianthi und bestätigen die Bedeutung physiologischer Aspekte von Isolaten innerhalb derselben Gattung bei der Betrachtung taxonomischer Probleme in der Coelomyceten-Gattung Phomopsis. [source] Clustering work and family trajectories by using a divisive algorithmJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 4 2007Raffaella Piccarreta Summary., We present an approach to the construction of clusters of life course trajectories and use it to obtain ideal types of trajectories that can be interpreted and analysed meaningfully. We represent life courses as sequences on a monthly timescale and apply optimal matching analysis to compute dissimilarities between individuals. We introduce a new divisive clustering algorithm which has features that are in common with both Ward's agglomerative algorithm and classification and regression trees. We analyse British Household Panel Survey data on the employment and family trajectories of women. Our method produces clusters of sequences for which it is straightforward to determine who belongs to each cluster, making it easier to interpret the relative importance of life course factors in distinguishing subgroups of the population. Moreover our method gives guidance on selecting the number of clusters. [source] Measuring beta-diversity from taxonomic similarityJOURNAL OF VEGETATION SCIENCE, Issue 6 2007Giovanni Bacaro Abstract Question: The utility of beta (,-) diversity measures that incorporate information about the degree of taxonomic (dis)similarity between species plots is becoming increasingly recognized. In this framework, the question for this study is: can we define an ecologically meaningful index of ,-diversity that, besides indicating simple species turnover, is able to account for taxonomic similarity amongst species in plots? Methods: First, the properties of existing measures of taxonomic similarity measures are briefly reviewed. Next, a new measure of plot-to-plot taxonomic similarity is presented that is based on the maximal common subgraph of two taxonomic trees. The proposed measure is computed from species presences and absences and include information about the degree of higher-level taxonomic similarity between species plots. The performance of the proposed measure with respect to existing coefficients of taxonomic similarity and the coefficient of Jaccard is discussed using a small data set of heath plant communities. Finally, a method to quantify ,-diversity from taxonomic dissimilarities is discussed. Results: The proposed measure of taxonomic ,-diversity incorporates not only species richness, but also information about the degree of higher-order taxonomic structure between species plots. In this view, it comes closer to a modern notion of biological diversity than more traditional measures of ,-di-versity. From regression analysis between the new coefficient and existing measures of taxonomic similarity it is shown that there is an evident nonlinearity between the coefficients. This nonlinearity demonstrates that the new coefficient measures similarity in a conceptually different way from previous indices. Also, in good agreement with the findings of previous authors, the regression between the new index and the Jaccard coefficient of similarity shows that more than 80% of the variance of the former is explained by the community structure at the species level, while only the residual variance is explained by differences in the higher-order taxonomic structure of the species plots. This means that a genuine taxonomic approach to the quantification of plot-to-plot similarity is only needed if we are interested in the residual system's variation that is related to the higher-order taxonomic structure of a pair of species plots. [source] Multivariate exploratory analysis of ordinal data in ecology: Pitfalls, problems and solutionsJOURNAL OF VEGETATION SCIENCE, Issue 5 2005János Podani Abstract Questions: Are ordinal data appropriately treated by multivariate methods in numerical ecology? If not, what are the most common mistakes? Which dissimilarity coefficients, ordination and classification methods are best suited to ordinal data? Should we worry about such problems at all? Methods: A new classification model family, OrdClAn (Ordinal Cluster Analysis), is suggested for hierarchical and non-hierarchical classifications from ordinal ecological data, e.g. the abundance/dominance scores that are commonly recorded in relevés. During the clustering process, the objects are grouped so as to minimize a measure calculated from the ranks of within-cluster and between-cluster distances or dissimilarities. Results and Conclusions: Evaluation of the various steps of exploratory data analysis of ordinal ecological data shows that consistency of methodology throughout the study is of primary importance. In an optimal situation, each methodological step is order invariant. This property ensures that the results are independent of changes not affecting ordinal relationships, and guarantees that no illusory precision is introduced into the analysis. However, the multivariate procedures that are most commonly applied in numerical ecology do not satisfy these requirements and are therefore not recommended. For example, it is inappropriate to analyse Braun-Blanquet abudance/dominance data by methods assuming that Euclidean distance is meaningful. The solution of all problems is that the dissimilarity coefficient should be compatible with ordinal variables and the subsequent ordination or clustering method should consider only the rank order of dissimilarities. A range of artificial data sets exemplifying different subtypes of ordinal variables, e.g. indicator values or species scores from relevés, illustrate the advocated approach. Detailed analyses of an actual phytosociological data set demonstrate the classification by OrdClAn of relevés and species and the subsequent tabular rearrangement, in a numerical study remaining within the ordinal domain from the first step to the last. [source] Direct measurement of spatial autocorrelation at the community level in four plant communitiesJOURNAL OF VEGETATION SCIENCE, Issue 6 2000Maia Mistral Abstract. Four sites were sampled to determine spatial autocorrelation in vegetation at the community level. All were in western New Zealand, but on different substrates and of different physiognomy: a terrace forest, a floodplain forest, a mire and the middle of a logging road. In ,dissimograms'the four communities all showed steady increases in dissimilarity with distance, but with shoulders in the curve for some sites, which could be related to plant morphology. Most of the increase in dissimilarity occurred over very short distances: less than 0.5 m in the forests, less than 1 m in the mire and less than 2 m in the road. Separate analyses of the woody and herbaceous guilds in the floodplain forest showed that herbaceous dissimilarities remained low at distances up to 20 m, probably because of clonal structure in some species. The mire showed low overall dissimilarity, which is attributed to the uniform substrate and the small species pool. Simulations showed that the approach is capable of indicating structure when it is present. Although the dissimogram was clearest when analysing a simulated grid of patches, other types of simulated patchiness showed dissimograms that were clearly distinguishable from those obtained from the vegetation studied. The almost continuous rise in dissimilarity with distance found in the four sites offers no support to the Hierarchy theory, fitting much more closely the alternative Continuum theory. [source] Climate and habitat barriers to dispersal in the highly mobile grey wolfMOLECULAR ECOLOGY, Issue 8 2004ELI GEFFEN Abstract We reanalysed published data to evaluate whether climate and habitat are barriers to dispersal in one of the most mobile and widely distributed mammals, the grey wolf (Canis lupus). Distance-based redundancy analysis (dbRDA) was used to examine the amount of variation in genetic distances that could be explained by an array of environmental factors, including geographical distance. Patterns in genetic variation were also examined using MDS plots among populations and relationships between genetic structure and individual environmental variables were further explored using the BIOENV procedure. We found that, contrary to a previous report, a pattern of isolation with distance is evident on a continental scale in the North American wolf population. This pattern is apparently related to climate and habitat. Specifically, vegetation types appear to play a role in the genetic dissimilarities among populations. When we controlled for the effect of spatial variation, climate was still associated with genetic distance. Further, partitioning of geographical distances into latitudinal and longitudinal axes revealed that the east,west gradient had the strongest relationship with genetic distance. We suggest two possible mechanisms by which environmental conditions may influence the dispersal decisions made by wolves. [source] Identification of differentially expressed proteins in papillary thyroid carcinomas with V600E mutation of BRAFPROTEOMICS - CLINICAL APPLICATIONS, Issue 7 2007Efisio Puxeddu Abstract BRAF, a serine/threonine kinase of the RAF family, is a downstream transducer of the RAS-regulated MAPK pathway. V600E mutation of BRAF protein is the most common genetic alteration occurring in papillary thyroid carcinomas and is prognostic of poor clinicopathological outcomes. Protein expression in the subclass of PTC bearing the BRAFV600E mutation was investigated by using 2-DE and MS/MS techniques and compared to that of matched normal thyroid tissues from seven patients. 2-D gel image analysis revealed that the expression of eight polypeptide spots, corresponding to five proteins, were significantly underexpressed in PTC bearing BRAFV600E mutation whereas 25 polypeptides, representing 19 distinct proteins, were significantly upregulated in tumour tissue, as compared to normal thyroid. Among the differentially expressed polypeptides, mitochondrial proteins, ROS-scavenger enzymes, apoptosis-related proteins as well as proteins involved in tumour cell proliferation were identified. Although dissimilarities between the present results and those previously reported can be ascribed to the use of different 2-DE techniques, the possibility that BRAFV600E mutation is responsible for changes in protein expression distinct from those induced by other oncogenes cannot be ruled out. [source] Using topographic wetness index in vegetation ecology: does the algorithm matter?APPLIED VEGETATION SCIENCE, Issue 4 2010Martin Kopecký Abstract Questions: How important is the choice of flow routing algorithm with respect to application of topographic wetness index (TWI) in vegetation ecology? Which flow routing algorithms are preferable for application in vegetation ecology? Location: Forests in three different regions of the Czech Republic. Methods: We used vegetation data from 521 georeferenced plots, recently sampled in a wide range of forest communities. From a digital elevation model, we calculated 11 variations of TWI for each plot with 11 different flow routing algorithms. We evaluated the performance of differently calculated TWI by (1) Spearman rank correlation with average Ellenberg indicator values for soil moisture, (2) Mantel correlation coefficient between dissimilarities of species composition and dissimilarities of TWI and (3) the amount of variation in species composition explained by canonical correspondence analysis. Results: The choice of flow routing algorithm had a considerable effect on the performance of TWI. Correlation with Ellenberg indicator values for soil moisture, Mantel correlation coefficient and explained variation doubled when the appropriate algorithm was used. In all regions, multiple flow routing algorithms performed best, while single flow routing algorithms performed worst. Conclusions: We recommend the multiple flow routing algorithms of Quinn et al. and Freeman for application in vegetation ecology. [source] Improving the assessment of species compositional dissimilarity in a priori ecological classifications: evaluating map scale, sampling intensity and improvement in a hierarchical classificationAPPLIED VEGETATION SCIENCE, Issue 4 2010B.E. Lawson Abstract Question: Can species compositional dissimilarity analyses be used to assess and improve the representation of biodiversity patterns in a priori ecological classifications? Location: The case study examined the northern-half of the South-east Queensland Bioregion, eastern Australia. Methods: Site-based floristic presence,absence data were used to construct species dissimilarity matrices (Kulczynski metric) for three levels of Queensland's bioregional hierarchy , subregions (1:500 000 scale), land zones (1:250 000 scale) and regional ecosystems (1:100 000 scale). Within- and between-class dissimilarities were compiled for each level to elucidate species compositional patterns. Randomized subsampling was used to determine the minimum site sampling intensity for each hierarchy level, and the effects of lumping and splitting illustrated for several classes. Results: Consistent dissimilarity estimates were obtained with five or more sites per regional ecosystem, 10 or more sites per land zone, and more than 15 sites per subregion. On average, subregions represented 4% dissimilarity in floristic composition, land zones approximately 10%, and regional ecosystems over 19%. Splitting classes with a low dissimilarity increased dissimilarity levels closer to average, while merging ecologically similar classes with high dissimilarities reduced dissimilarity levels closer to average levels. Conclusions: This approach demonstrates a robust and repeatable means of analysing species compositional dissimilarity, determining site sampling requirements for classifications and guiding decisions about ,lumping' or ,splitting' of classes. This will allow more informed decisions on selecting and improving classifications and map scales in an ecologically and statistically robust manner. [source] The Return of the Future: A Second Go at Robotic ConstructionARCHITECTURAL DESIGN, Issue 4 2010Martin Bechthold Abstract The last few years have witnessed a robotic revival with a reinvigoration of interest in what the robot can offer the construction industry. Martin Bechthold looks back at the first robotic boom during the 1980s and 1990s when millions of Japanese yen were invested in developing robots that could address the shortage of construction labour. Bechthold further explores the similarities and dissimilarities of the current and previous periods of activity, as supported by his research at Harvard's Graduate School of Design (GSD). Copyright © 2010 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||