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Piroplasms, tick-transmitted Apicomplexa of the genera Theileria, Babesia and Cytauxzoon, are blood-borne parasites of clinical and veterinary importance. The order Piroplasmida shows a puzzling systematics characterized by multiple clades, soft polytomies and paraphyletic/polyphyletic genera. In the present study, screening of platypuses (Ornithorhynchus anatinus), was performed to infer the parasite molecular phylogeny. DNA was extracted from blood, ectoparasites and tick eggs and the 18S rRNA– hsp70–genes were used for the phylogenetic reconstructions. Microscopic analyses detected pleomorphic intra-erythrocytic organisms and tetrads consistent with previous descriptions of Theileria ornithorhynchi Mackerras, 1959, but observation of possible schizonts could not be confirmed. DNA sequences obtained from blood and ticks allowed resolving the systematics of the first piroplasm infecting a monotreme host. Molecularly, T. ornithorhynchi formed a novel monophyletic group, basal to most known piroplasms’ clades. The ancestral position of this clade, isolated from an ancient lineage of mammalian host appears particularly fascinating. The present paper discusses the inadequacies of the current molecular systematics for the Piroplasmida and the consequences of incomplete sampling, morphology-based classification and ambiguous microscopic identifications. Likely when the current sampling bias is rectified and more sequence data is made available, the phylogenetic position of T. ornithorhynchi will be further contextualized without ambiguity.

Little is known about the prevalence and pathogenesis of trypanosomes in Australian monotremes, and few genetic characterisation studies have been conducted with these haemoparasites. During the present investigation, molecular and microscopic methods were used to screen peripheral blood (n= 28) and ectoparasites (n= 10 adult ticks; n= 5 tick nymphs; n= 1 leech; and n>. 500 tick eggs) collected from wild Tasmanian platypuses (Ornithorhynchus anatinus), for the presence of trypanosomatid-specific DNA and/or trypomastigotes. The genes for the small ribosomal subunit RNA (18S rDNA) and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) were amplified and sequenced, prior to conducting phylogenetic analyses.The detection rate of the parasite-specific 18S rDNA in platypus blood was 85.7% (n= 24/28), and the leech was also positive at both loci. Microscopically, high parasitaemia and the presence of abundant trypomastigotes, morphologically consistent with Trypanosoma binneyi Mackerras (1959), were observed in the blood films. Phylogenetic analyses at the 18S locus revealed the existence of four trypanosomatid-like genotypes, with variable similarity to two previously-described genotypes of T. binneyi (range of genetic p-distance: 0.0-0.5%). For the gGAPDH locus, for which only one T. binneyi sequence is available in GenBank, three genotypes closely related T. binneyi were identified (range of genetic p-distance: 0.1-0.4%). The leech-derived trypanosome isolate was virtually identical (at the two loci studied) to the other parasites sequenced from infected platypuses; however, the molecular or morphological identification of the leech species was not possible.Although further studies are required, the molecular detection of trypanosomes in an aquatic leech removed from a platypus, suggests the possibility that these haematophagous hirudineans may be a vector for T. binneyi (and closely related genotypes).

Piroplasms belonging to genera Theileria and Babesia (Phylum: Apicomplexa) are vector-borne protozoan haemoparasites with similar phenotype that infect erythrocytes of domesticated mammals and wildlife including birds. In addition, piroplasms of Theileria have an exoerythrocytic life cycle stage within the host’s white blood cells. Observations of intraerythrocytic piroplasms have been made sporadically in peripheral blood films of Australian native mammals since the first report was made nearly a Century ago and the advent of PCR has stimulated renewed research interest and descriptions of the molecular phylogeny of these organisms in a variety of marsupial hosts. A piroplasm (Theileria ornithorhynchi) has been described in previous studies of the platypus (Ornithorhynchus anatinus). As part of a study into the health and ecology of this iconic monotreme, blood samples were collected for haematological and biochemical analysis from wild-trapped platypuses in Tasmania. A subset of these samples, together with their ectoparasites, was evaluated for piroplasm infections by blood film microscopy and molecular analysis of the 18S ribosomal RNA gene, and phylogenetic analysis was performed with NJ trees using BIONJ. Estimates of evolutionary divergence between sequences were calculated by MEGA 5. A total of 27 blood samples and eight ectoparasites (seven ticks, one leech) were examined from 27 platypuses. All ticks were identified as Ixodes ornithorhynchi. Piroplasm infections were highly prevalent in the population studied (27/27; 100% infected); organisms were pleomorphic with infrequent tetrads and intra-leukocytic forms, thought to be Theileria schizonts, were occasionally observed. Anaemia was not detected. Many platypuses were co-infected with trypanosomes. All blood samples and three ectoparasites were positive for piroplasm DNA and phylogenetic analysis suggested the presence of more than one piroplasm species. This study emphasises the importance of combining tr

This essay focuses on pathfinding in a 2.5D game world for Non-playing Characters (NPC) and agents. The primary focus is to investigate and determine the optimal pathfinding strategy based on several measures such as steps and time taken to reach the goal. For this investigation the most popular pathfinding algorithms and interaction schemes will be analyzed and tested using standard analysis techniques and test applications. The result of this analysis and testing is that it is shown that the A* algorithm is optimal using the Manhattan distance heuristic. Unfortunately, our testing did not reveal an optimal choice among the three interaction scheme that was tested which were cooperative, non-cooperative and competitive., 2009-02

This paper compares and contrasts the sustainable livelihoods framework and value chain analysis approaches to researching producer to market linkages in developing nations. This review of contemporary methodology and research reveals that both methods offer major strengths and weaknesses. Whereas the sustainable livelihoods framework may offer a contextualized picture of the producer community and identify potential means for improving livelihoods, it has difficulty quantifying such findings to make a strong case for the differences that may be achieved. Contrastingly, value chain analysis has trouble creating a comprehensive picture of market interaction and often requires data not available, risking an inaccurate result. The final product does however, offer statistical explanation of how wealth is generated and often unevenly distributed in the chain, making a stronger case for policy changes. Finding such complementary strengths and weaknesses, the paper advocates combining qualitative and quantitative methods as well as social science and economic analysis to produce more effective research overall.

This article reports 2 experiments that investigated performance on a novel insight problem, the 8-coin problem. The authors hypothesized that participants would make certain initial moves (strategic moves) that seemed to make progress according to the problem instructions but that nonetheless would guarantee failure to solve the problem. Experiment 1 manipulated the starting state of the problem and showed that overall solution rates were lower when such strategic moves were available. Experiment 2 showed that failure to capitalize on visual hints about the correct first move was also associated with the availability of strategic moves. The results are interpreted in terms of an information-processing framework previously applied to the 9-dot problem. The authors argue that in addition to the operation of inappropriate constraints, a full account of insight problem solving must incorporate a dynamic that steers solution-seeking activity toward the constraints.

The nine-dot problem is a classic in the field of human problem solving. Cognitive accounts of the problem's difficulty have been criticized on the grounds that the experimental methods on which they rely for support involve a qualitative change to the task requirements of the problem. The three experiments reported here utilize visual and visual-procedural hints to examine the notion that its difficulty is rooted in a mismatch between problem shape and solution shape. Experiment 1 demonstrated that a perceptual cue to the shape of the solution in the form of shading gave rise to only minimal improvements in performance; an additional hint about the relevance of the shading gave rise to modest, but not statistically significant, improvements. Experiment 2 replicated these findings against an additional control condition in which a solely verbal hint to violate the perceptual boundary of the problem shape was given. Furthermore, when both the verbal and visual hints were provided, performance improved only slightly. Experiment 3 provided participants with experience in producing the shape of the correct solution in problem variants closely related to the nine-dot problem. Performance on the transfer task, the basic nine-dot problem, remained at floor, however. These data suggest that visual constraint relaxation is unlikely to be the sole process by which the insight required to find a solution is achieved. The results are interpreted in terms of a previously proposed computational model of performance.