865 resultados para Phylogenetic Groups


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The Australian species of Allomethus and Claraeola are revised and include one described species, Claraeola erinys (Perkins), and five new species: Allomethus unicicolis sp. n., Claraeola cyclohirta sp. n., C. sicilis sp. n., C. spargosis sp. n., and C. yingka sp. n.. Claraeola hylaea (Perkins) is proposed to be a synonym of C. erinys (Perkins). A key to species is provided and male and female genitalia are illustrated. The Australian species are placed phylogenetically into a world context using available taxa within the Allomethus genus group. The phylogenetic relationships are discussed in light of a cladistic analysis involving 22 taxa and 60 characters.

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This paper reports the findings of an exploratory qualitative study examining parish awareness of the need to include individuals with disability in genuine and meaningful ways. Based on the interviews of over thirty persons, including people with disability, parents, parish workers, volunteers and human service workers within church agencies in the Catholic Archdiocese of Brisbane, Australia, the authors devised a process for including individuals in parishes. This process, known as a Disability Focus Group, was then implemented in one parish as a pilot study. The outcomes of the pilot are discussed.

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If the cestodes are excluded, then the parasitic platyhelminths of fishes divide neatly into the external and monoxenous Monogenea and the internal and heteroxenous Digenea. Both groups have apparently had long associations of coevolution, host switching and adaptation with fishes and have become highly successful in their respective habitats. Current estimates of species richness for the two groups suggest that they may be remarkably similar. Here we consider the nature of the diversity of the Monogenea. and Digenea of fishes in terms of richness of species and higher taxa to determine what processes may be responsible for observed differences. The Monogenea includes at least two super-genera (Dactylogyrus and Gyrodactylus) each of which has hundreds of species, no comparable genera are found in the Digenea. Possible reasons for this difference include the higher host specificity of monogeneans and their shorter generation Lime. If allowance is made for the vagaries of taxonomic 'lumping' and 'splitting', then there are probably comparable numbers of families of monogeneans and digeneans in fishes. However, the nature of the families differ profoundly. Richness in higher taxa (families) in the Digenea is explicable in terms of processes that appear to have been unimportant in the Monogenea. Readily identifiable sources of diversity in the Digenea are: recolonisation of fishes by taxa that arose in association with tetrapods; adoption of new sites within hosts; adoption of new diets and feeding mechanisms; adaptations relating to the exploitation of ecologically similar groups of fishes and second intermediate hosts; and adaptations relating to the exploitation of phylogenetic lineages of molluscs. In contrast, most higher- level monogenean diversity (other than that associated with the subclasses) relates principally to morphological specialisation for attachment by the haptor. (C) 2002 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.

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Nine novel arsenite-oxidizing bacteria have been isolated from two different gold mine environments in Australia. Four of these organisms grow chemolithoautotrophically with oxygen as the terminal electron acceptor, arsenite as the electron donor, and carbon dioxide-bicarbonate as the sole carbon source. Five heterotrophic arsenite-oxidizing bacteria were also isolated, one of which was found to be both phylogenetically and physiologically identical to the previously described heterotrophic arsenite oxidizer misidentified as Alcaligenes faecalis. The results showed that this strain belongs to the genus Achromobacter. Phylogenetically, the arsenite-oxidizing bacteria fall within two separate subdivisions of the Proteobacteria. Interestingly, the chemolithoautotrophic arsenite oxidizers belong to the alpha-Proteobacteria, whereas the heterotrophic arsenite oxidizers belong to the beta-Proteobacteria.

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Sequences of the rRNA nontranscribed spacer (NTS) were determined for six isolates of Perkinsus olseni, seven isolates of Perkinsus sp. from Anadara trapezia and one isolate of Perkinsus sp. from Austrovenus stutchburyi. These sequences were compared with previously published NTS sequences for R atlanticus, P. marinus and P. andrewsi. Consensus sequences for Perkinsus olseni, the Perkinsus isolates and P. atlanticus were approximately 98-99% similar to each other but only 65-79% similar to P. marinus and P. andrewsi sequences. Some individual P. olseni sequences were less similar to each other (97.4%) than they were to P. atlanticus sequences (97.8-98.2%), therefore NTS provides further evidence that P. atlanticus, P. olseni, Perkinsus sp. from Anadara trapezia and Perkinsus sp. from Austrovenus stutchburyi are conspecific. We propose that P. atlanticus be synonymised with P. olseni Lester & Davis, 1981 which has taxonomic priority, and that Perkinsus sp. from Anadara trapezia and Perkinsus sp. from Austrovenus stutchburyi belong to R olseni sensu lato as well. A phylogenetic analysis of SSU rDNA, incorporating recently published Perkinsus sequences, supports the placement of the Perkinsus species with Parvilucifera infectans within the Dinoflagellata.

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With over 80 000 described species, Brachycera represent one of the most diverse clades of organisms with a Mesozoic origin. Larvae of the majority of early lineages are detritivores or carnivores. However, Brachycera are ecologically innovative and they now employ a diverse range of feeding strategies. Brachyceran relationships have been the subject of numerous qualitative analyses using morphological characters. These analyses are often based on characters from one or a few character systems and general agreement on relationships has been elusive. In order to understand the evolution of basal brachyceran lineages, 101 discrete morphological characters were scored and compiled into a single data set. Terminals were scored at the family level, and the data set includes characters from larvae, pupae and adults, internal and external morphology, and male and female terminalia. The results show that all infraorders of Brachycera are monophyletic, but there is little evidence for relationships between the infraorders. Stratiomyomorpha, Tabanomorpha, and Xylophagomorpha together form the sister group to Muscomorpha. Xylophagomorpha and Tabanomorpha are sister groups. Within Muscomorpha, the paraphyletic Nemestrinoidea form the two most basal lineages. There is weak evidence for the monophyly of Asiloidea, and Hilarimorphidae appear to be more closely related to Eremoneura than other muscomorphs. Apsilocephalidae, Scenopinidae and Therevidae form a clade of Asiloidea. This phylogenetic evidence is consistent with the contemporaneous differentiation of the main brachyceran lineages in the early Jurassic. The first major radiation of Muscomorpha were asiloids and they may have diversified in response to the radiation of angiosperms in the early Cretaceous.

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The present research focused on responses of low-status group members to a merger with a high-status group. A study was conducted (N = 153) in which the alignment of the leader for the merged group (ingroup vs. outgroup) and leader behavior (equality, outgroup favoritism, ingroup favoritism, complementarity) were manipulated. The authors predicted that the leader, by his or her behavior, would play an important role in defining the new relationship between premerger groups. Overall, low-status ingroup leaders were evaluated more positively than high-status outgroup leaders. Ingroup leaders were evaluated more favorably and were more likely to engender a common identity in the merged group than were outgroup leaders when leaders behaved in an ingroup-favoring or complementary fashion. In contrast, evaluations of ingroup and outgroup leaders did not differ when the leader stressed equality or was outgroup favoring. The findings demonstrate the important role leaders can play in accentuating or de-emphasizing premerger status differences.

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This study integrated the research streams of computer-mediated communication (CMC) and group conflict by comparing the expression of different types of conflict in CMC groups and face-to face (FTF) groups over time. The main aim of the study was to compare the cues-filtered-out approach against the social information processing theory A laboratory study was conducted with 39 groups (19 CMC and 20 FTF) in which members were required to work together over three sessions. The frequencies of task, process, and relationship conflict were analyzed. Findings supported the social information processing theory. There was more process and relationship conflict in CMC groups compared to FTF groups on Day 1. However, this difference disappeared on Days 2 and 3. There was no difference between CMC and FTF groups in the amount of task conflict expressed on any day.

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To examine the dissemination of Shiga-toxigenic Escherichia coli (STEC) within cattle groups, dairy calves on two farms utilizing different calf-rearing practices were exposed to a traceable STEC strain. Test strain dissemination differed significantly between farms, with a higher prevalence being associated with group penning. Pen floors and calf hides may be the main environmental mechanisms of transmission. Dairy calf husbandry represents a control point for reducing on-farm STEC prevalence.

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The adsorption of three aromatic compounds on to an untreated carbon was investigated. The solution pH was lowered in all experiments so that all the solutes were in their molecular forms. It was shown that the difference in the maximum adsorption of the solutes was mainly a result of the difference in the sizes of the molecules and their functional groups. Further-more, it was illustrated that the packing arrangement was most likely edge-to-face (sorbate-sorbent) with various tilt angles. On the other hand, the affinity and heterogeneity of the adsorption systems were apparently related to the pK(a) values of the solutes.

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What causes species richness to vary among different groups of organisms? Two hypotheses are that large geographical ranges and fast life history either reduce extinction rates or raise speciation rates, elevating a clade's rate of diversification. Here we present a comparative analysis of these hypotheses using data on the phylogenetic relationships, geographical ranges and life history of the terrestrial mammal fauna of Australia. By comparing species richness patterns to null models, we show that species are distributed nonrandomly among genera. Using sister-clade comparisons to control for clade age, we then find that faster diversification is significantly associated with larger geographical ranges and larger litters, but there is no evidence for an effect of body size or age at first breeding on diversification rates. We believe the most likely explanation for these patterns is that larger litters and geographical ranges increase diversification rates because they buffer species from extinction. We also discuss the possibility that positive effects of litter size and range size on diversification rates result from elevated speciation rates.

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Although the co-ordination of promotive root-sourced cytokinin (CK) and inhibitory shoot apex-sourced auxin (IAA) is central to all current models on lateral bud dormancy release, control by those hormones alone has appeared inadequate in many studies. Thus it was hypothesized that the IAA : CK model is the central control but that it must be considered within the relevant timeframe leading to lateral bud release and against a backdrop of interactions with other hormone groups. Therefore, IAA and a wide survey of cytokinins (CKs), were examined along with abscisic acid (ABA) and polyamines (PAs) in released buds, tissue surrounding buds and xylem sap at 1 and 4 h after apex removal, when lateral buds of chickpea are known to break dormancy. Three potential lateral bud growth inhibitors, IAA, ABA and cis-zeatin 9-riboside (ZR), declined sharply in the released buds and xylem following decapitation. This is in contrast to potential dormancy breaking CKs like trans-ZR and trans-zeantin 9-riboside 5'phosphate (ZRMP), which represented the strongest correlative changes by increasing 3.5-fold in xylem sap and 22-fold in buds. PAs had not changed significantly in buds or other tissues after 4 h, so they were not directly involved in the breaking of bud dormancy. Results from the xylem and surrounding tissues indicated that bud CK increases resulted from a combination synthesis in the bud and selective loading of CK nucleotides into the xylem from the root.

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Objective: To compare head relocation accuracy in traumatic ( whiplash), insidious onset neck pain patients and asymptomatic subjects when targeting a natural head posture (NHP) and complex predetermined positions. Design: A case-control study. Setting: University-based musculoskeletal research clinic. Participants: Sixty-three volunteers divided into three groups of similar gender and age: Group 1 (n=21) an asymptomatic group; group 2 (n=20) insidious onset neck pain; group 3 (n=22) a history of whiplash injury. Intervention: Five randomly ordered tests designed to detect relocation accuracy of the head. Outcome measures: A 3-Space Fastrak system measured the mean absolute relocation error of three trials of each relocation test. Results: A significant difference was found between groups in one of the tests targeting the NHP (p=0.001). Post-hoc pairwise comparisons revealed a significant difference (pless than or equal to0.05) between the asymptomatic group and each symptomatic group. The difference between the symptomatic groups just failed to reach significance (p=0.07). None of the other four tests revealed significant differences. Conclusion: The test of targeting the NHP indicates that relocation inaccuracy exists in patients with neck pain with a trend to suggest that the deficit may be greater in whiplash patients. Tests employing unfamiliar postures or more complex movement were not successful in differentiating subject groups.