Home About us Contact
|
Home About us Contact | ||
|
|
||
Combined Data Set (combined + data_set)
Selected AbstractsMorphological and Pathological Variability in Rice Isolates of Rhizoctonia solani and Molecular Analysis of their Genetic VariabilityJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2007S. Guleria Abstract Nineteen isolates of Rhizoctonia solani collected from different rice varieties grown in various regions of Punjab were studied for their morphological and pathological characterization. Majority of the isolates were fast growing with raised and fluffy colonies and hyphal width of 9.6 ,m while four exhibited moderate growth rate. Colony colour in all except two isolates was light yellowish brown. While sclerotial number per 5.0 mm culture disc of the test isolates ranged between 2.1 and 11.2 mm, their size varied between 1.31 and 2.08 mm. Sclerotial colour in all except two isolates was dark brown and most of these were found scattered in the colony. There was no relationship between morphologically similar isolates and their pathogenic behaviour. Majority of the isolates produced lesion length between 45.6 and 58.2 mm on detached rice leaves (cv. PR116). Molecular characterization of genetic diversity in the test isolates was studied by using 10 inter simple sequence repeats (ISSR) and eight random amplified polymorphic DNA (RAPD) markers. The size of amplified DNA bands ranged from 0.25,3.0 to 0.5,4.0 kb with ISSR and RAPD markers, respectively. Combined data set of 155 DNA markers were analysed with UPGMA resulting five clusters with 49,89% genetic similarity. Most of the isolates showed grouping specific to the host variety. Out of these two types of DNA markers, RAPD markers were able to detect more genetic variability when compared to ISSR markers. [source] Root and butt rot of Todo fir (Abies sachalinensis) caused by Heterobasidion annosum s.l. in Hokkaido, JapanFOREST PATHOLOGY, Issue 3 2007S. Tokuda Summary The occurrence and symptoms of root and butt rot were examined in a 35 × 30 m plot of 68-year-old Todo fir plantation in Hokkaido, Japan. Forty-seven percent of the cut stumps were decayed and 52% of the decayed stumps showed similar decay characteristics with yellowish orange to light brown colouration and expanded pockets in the heartwood. Morphological characteristics of the pure cultures isolated from the decay were similar to the cultures isolated from basidiocarps of Heterobasidion annosum sensu lato, found on fallen logs outside of the research site. Also DNA analysis based on the combined data set of three gene loci (glyceraldehyde 3-phosphate dehydrogenase, heat shock protein 80,1 and elongation factor 1-alpha genes) showed that the isolates from the decay are included in the same clade with the Japanese H. annosum s.l. isolates. They form a subclade to H. parviporum (the European S group of H. annosum s.l.). This is the first report of molecular determination of H. annosum s.l. isolated from root and butt rot in a plantation in Japan. [source] The role of private providers in treating child diarrhoea in Latin AmericaHEALTH ECONOMICS, Issue 1 2008Hugh R. Waters Abstract Diarrhoeal disease, a leading cause of child mortality, disproportionately affects children in low-income countries , where private and non-governmental providers are often an important source of health care. We use 10 Living Standards Measurement Surveys from Latin America to model the choice of care for child diarrhoea in the private sector compared to the public sector. A total of 36.8% of children in the combined data set saw a private provider rather than a public one when taken for treatment. Each additional quintile of household economic status is associated with an increase of 6.5 percentage points in the probability that a child with diarrhoea is taken to a private provider (p<0.001). However, treatments provided in the private sector are manifestly of worse quality than in the public sector. A total of 33.0% of children visiting a public provider received Oral Rehydration Solution, compared to 13.7% of those visiting a private provider. Conversely, children treated by a private provider are more likely to receive drugs, most commonly unnecessary antibiotics. Ironically, when it comes to treatment for child diarrhoea, wealthier and better educated households in Latin America are paying for treatment in the private sector that is ineffective in comparison with treatments that are commonly and inexpensively available. Copyright © 2007 John Wiley & Sons, Ltd. [source] Molecular phylogeny of Diabrotica beetles (Coleoptera: Chrysomelidae) inferred from analysis of combined mitochondrial and nuclear DNA sequencesINSECT MOLECULAR BIOLOGY, Issue 4 2001T. L. Clark Abstract The phylogenetic relationships of thirteen Diabrotica (representing virgifera and fucata species groups) and two outgroup Acalymma beetle species (Coleoptera: Chrysomelidae) were inferred from the phylogenetic analysis of a combined data set of 1323 bp of mitochondrial DNA (mtDNA) cytochrome oxidase subunit 1 (COI) and the entire second internal transcribed spacer region (ITS-2) of nuclear ribosomal DNA of 362 characters. Species investigated were D. adelpha, D. balteata, D. barberi, D. cristata, D. lemniscata, D. longicornis, D. porracea, D. speciosa, D. undecimpunctata howardi, D. u. undecimpunctata, D. virgifera virgifera, D. v. zeae, D. viridula, and outgroup A. blandulum and A. vittatum. Maximum parsimony (MP), minimum evolution (ME), and maximum likelihood (ML) analyses of combined COI and ITS-2 sequences clearly place species into their traditional morphological species groups with MP and ME analyses resulting in identical topologies. Results generally confer with a prior work based on allozyme data, but within the virgifera species group, D. barberi and D. longicornis strongly resolve as sister taxa as well as monophyletic with the neotropical species, D. viridula, D. cristata and D. lemniscata also resolve as sister taxa. Both relationships are not in congruence with the prior allozyme-based hypothesis. Within the fucata species group, D. speciosa and D. balteata resolve as sister taxa. Results also strongly supported the D. virgifera and D. undecimpunctata subspecies complexes. Our proposed phylogeny provides some insight into current hypotheses regarding distribution status and evolution of various life history traits for Diabrotica. [source] The Virtual International Stroke Trials Archive (VISTA): results and impact on future stroke trials and management of stroke patientsINTERNATIONAL JOURNAL OF STROKE, Issue 2 2010C. Weimar Background The Virtual International Stroke Trials Archive was established to improve stroke care and trial design through the collation, categorization and potential access to data sets from clinical trials for the treatment of stroke. Methods Virtual International Stroke Trials Archive currently provides access to a combined data set of 29 anonymised acute stroke trials and one acute stroke registry with data on >27 500 patients aged between 18 and 103 (mean 71) years. Results Virtual International Stroke Trials Archive has facilitated research across a broad canvas. The prognosis was poor in patients with very high blood pressure at the time of admission or with a wide variability of systolic blood pressure during the acute phase. The late occurrence of hyperthermia following an ischaemic stroke worsens the prognosis. Stroke lateralisation is not an important predictor of cardiac adverse events or 90-day mortality. Haemorrhagic transformation is seen frequently in patients with cardio-embolic strokes and is associated with a poor prognosis when occurring after the acute phase. Virtual International Stroke Trials Archive has allowed various prognostic models for patients with ischaemic or haemorrhagic stroke to be established and validated. More direct outcomes such as lesion volume can be useful in phase II clinical trials for determining whether a phase III trial should be undertaken. New outcome measures such as ,home time' may also strengthen future trials. On a worldwide level, the prognosis of stroke patients differs considerably between various countries. Conclusion Virtual International Stroke Trials Archive provides an excellent opportunity for analysis of natural history data and prognosis. It has the potential to influence clinical trial design and implementation through exploratory data analyses. [source] I-CAN: A New Instrument to Classify Support Needs for People with Disability: Part IJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 4 2009Vivienne C. Riches Background, The supports paradigm has shifted focus from assessing competence and deficits among people with disabilities to identifying supports needed to live meaningful and productive lives in inclusive settings. Consequently, a rigorous and robust system is required that is capable of accurately determining the type and intensity of support needed and of allocating resources accordingly. The aim of the present study was to develop such a system to identify and classify support needs of people with disabilities based on the conceptual framework of the International Classification of Functioning, Disability and Health (ICF) [WHO, The International Classification of Functioning, Disability and Health (ICF), Author, Geneva, 2001], and the supports concept [Mental Retardation: Definition, Classification and Systems of Support, 9th edn (1992), 10th edn (2002), American Association on Mental Retardation, Washington, DC). Method, A total of 1012 individuals with disabilities who were supported by accommodation and day programme organizations across the eastern states of Australia were assessed. The instrument was used in a team setting involving the person, their family and friends and staff as appropriate. Version 1 was administered with 595 people with disability. This version was refined according to qualitative and quantitative analyses. Another 342 individuals were assessed using Version 2, resulting in a combined data set for 936 individuals. Version 3 was then trialled with a further 76 individuals with disabilities. Results, Ten domain scales in Health and Well Being (HWB) and Activities and Participation (A&P) were explored and refined. The scales effectively discriminated a range of intensities of support for people with various disabilities, with the highest support needs generally recorded by individuals with multiple disabilities who were ageing. The instrument can be used to develop a profile of needed supports across the domain scales. These measure current and predicted support needs, and contribute to future planning. The team approach proved beneficial in this regard. Conclusions, The I-CAN is a useful instrument for effectively assessing the support needs of people with a disability using a person centred approach. It is effective in identifying support needs across health and well-being areas, and activities of daily living. [source] PHYLOGENY OF THE EUGLENALES BASED UPON COMBINED SSU AND LSU RDNA SEQUENCE COMPARISONS AND DESCRIPTION OF DISCOPLASTIS GEN.JOURNAL OF PHYCOLOGY, Issue 3 2006NOV. (EUGLENOPHYTA) A Bayesian analysis, utilizing a combined data set developed from the small subunit (SSU) and large subunit (LSU) rDNA gene sequences, was used to resolve relationships and clarify generic boundaries among 84 strains of plastid-containing euglenophytes representing 11 genera. The analysis produced a tree with three major clades: a Phacus and Lepocinlis clade, a Discoplastis clade, and a Euglena, Colacium, Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade. The majority of the species in the genus Euglena formed a well-supported clade, but two species formed a separate clade near the base of the tree. A new genus, Discoplastis, was erected to accommodate these taxa, thus making the genus Euglena monophyletic. The analysis also supported the monophyly of Colacium, Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena, which formed two subclades sister to the Euglena clade. Colacium, Trachelomonas, and Strombomonas, all of which produce copious amounts of mucilage to form loricas or mucilaginous stalks, formed a well-supported lineage. Our analysis supported retaining Strombomonas and Trachelomonas as separate genera. Monomorphina and Cryptoglena formed two well-supported clades that were sister to the Colacium, Trachelomonas, and Strombomonas clade. Phacus and Lepocinclis, both of which have numerous small discoid chloroplasts without pyrenoids and lack peristaltic euglenoid movement (metaboly), formed a well-supported monophyletic lineage that was sister to the larger Euglena through Cryptoglena containing clade. This study demonstrated that increased taxon sampling, multiple genes, and combined data sets provided increased support for internal nodes on the euglenoid phylogenetic tree and resolved relationships among the major genera in the photosynthetic euglenoid lineage. [source] Modern distribution of saltmarsh testate amoebae: regional variability of zonation and response to environmental variablesJOURNAL OF QUATERNARY SCIENCE, Issue 5-6 2002Dan J. Charman Abstract Sea-level reconstruction from biological indicators in saltmarsh sediments requires an understanding of the modern ecology of the organisms concerned. Previous work suggested that testate amoebae are a potential new group of organisms to use for sea-level reconstruction, especially combined with diatoms and foraminifera. This paper analyses data from three saltmarshes on the Taf estuary, South Wales, the River Erme, Devon, and at Brancaster, Norfolk (UK) to (i) test for the presence and zonation of testate amoebae in relation to elevation; (ii) examine the similarity of zonation patterns between marshes; and (iii) explore the relationship between assemblage composition and a wider range of environmental variables. In addition we provide an update on the identification of testate amoebae on saltmarshes. Our results confirm that at all sites the primary environmental gradient is tidal inundation. Major changes in taxa along the tidal gradient are similar except for the lowest elevations, where different taxa become dominant at different sites. Canonical correspondence analysis (CCA) shows that assemblage composition is also strongly related to other variables, independent of the tidal position. Salinity, particle size and organic matter content are particularly important, and there is a statistically significant geographical effect on assemblages. Relationships between sea-level and assemblage composition are often stronger for individual sites, suggesting that local data sets should be used for quantitative sea-level reconstructions. However, the combined data set would provide more robust estimates of past sea-level change from fossil data. Other environmental variables explain as much of the variability in species assemblages as tidal parameters and should be considered more often in sea-level reconstructions based on microfossil indicators. Copyright © 2002 John Wiley & Sons, Ltd. [source] Inferring the evolutionary history of Drosophila americana and Drosophila novamexicana using a multilocus approach and the influence of chromosomal rearrangements in single gene analysesMOLECULAR ECOLOGY, Issue 12 2008RAMIRO MORALES-HOJAS Abstract The evolutionary history of closely related organisms can prove sometimes difficult to infer. Hybridization and incomplete lineage sorting are the main concerns; however, genome rearrangements can also influence the outcome of analyses based on nuclear sequences. In the present study, DNA sequences from 12 nuclear genes, for which the approximate chromosomal locations are known, have been used to estimate the evolutionary history of two forms of Drosophila americana (Drosophila americana americana and Drosophila americana texana) and Drosophila novamexicana (virilis group of species). The phylogenetic analysis of the combined data set resulted in a phylogeny showing reciprocal monophyly for D. novamexicana and D. americana. Single gene analyses, however, resulted in incongruent phylogenies influenced by chromosomal rearrangements. Genetic differentiation estimates indicated a significant differentiation between the two species for all genes. Within D. americana, however, there is no evidence for differentiation between the chromosomal forms except at genes located near the X/4 fusion and Xc inversion breakpoint. Thus, the specific status of D. americana and D. novamexicana is confirmed, but there is no overall evidence for genetic differentiation between D. a. americana and D. a. texana, not supporting a subspecific status. Based on levels of allele and nucleotide diversity found in the strains used, it is proposed that D. americana has had a stable, large population during the recent past while D. novamexicana has speciated from a peripheral southwestern population having had an ancestral small effective population size. The influence of chromosomal rearrangements in single gene analyses is also examined. [source] Bilateral striopallidodentate calcinosis: Clinical characteristics of patients seen in a registryMOVEMENT DISORDERS, Issue 2 2001Bala V. Manyam MD Abstract Clinical features in bilateral striopallidodentate calcinosis (BSPDC), popularly referred to as Fahr's disease (five autosomal dominant families and eight sporadic cases, n = 38), recruited through a registry, are reported. Applying uniform criteria, cases reported in the literature (n = 61) were combined for detailed analysis. The mean (± S.D.) age of Registry patients was 43 ± 21 and that of literature was 38 ± 17. In combined data set (n = 99), 67 were symptomatic and 32 were asymptomatic. Of the symptomatic, the incidence among men was higher compared with women (45:22). Movement disorders accounted for 55% of the total symptomatic patients. Of the movement disorders, parkinsonism accounted for 57%, chorea 19%, tremor 8%, dystonia 8%, athetosis 5%, and orofacial dyskinesia 3%. Overlap of signs referable to different areas of central nervous system (CNS) was common. Other neurologic manifestations included: cognitive impairment, cerebellar signs, speech disorder, pyramidal signs, psychiatric features, gait disorders, sensory changes, and pain. We measured the total volume of calcification using an Electronic Planimeter and Coordinate Digitizer. Results suggest a significantly greater amount of calcification in symptomatic patients compared to asymptomatic patients. This study suggests that movement disorders are the most common manifestations of BSPDC, and among movement disorders, parkinsonism outnumber others. © 2001 Movement Disorder Society. [source] A molecular phylogeny and a revised classification of tribe Lepisoreae (Polypodiaceae) based on an analysis of four plastid DNA regionsBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010LI WANG Phylogenetic relationships within the palaeotropical tribe Lepisoroideae (Polypodiaceae) were investigated by studying sequence variation of four plastid DNA regions: rbcL, rps4 plus rps4-trnS IGS, trnL intron plus trnL-F IGS, rbcL-atpB IGS plus part of atpB. In total, over 4000 nucleotides were sequenced for 39 species. Seven well-supported clades were found in the analyses of the combined data set. We provide a new classification of Lepisoroideae by integrating phylogenetic results and known variation of morphological characters. The two small genera Neocheiropteris and Tricholepidium are supported as monophyletic, the genus Paragramma is resurrected and the genera Lepisorus, Neolepisorus, Lemmaphyllum and Lepidomicrosorium are re-circumscribed. We proposed 14 new combinations, among which Caobangia is treated as a synonym of Lemmaphyllum. A key for identifying the recognized genera is presented. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162, 28,38. [source] Angiosperm phylogeny inferred from 18S rDNA, vbcL, and atpB sequencesBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2000DOUGLAS E. SOLTIS A phylogenetic analysis of a combined data set for 560 angiosperms and seven outgroups based on three genes, 18S rDNA (1855 bp), rbcL (1428 bp), and atpB (1450 bp) representing a total of 4733 bp is presented. Parsimony analysis was expedited by use of a new computer program, the RATCHET. Parsimony jackknifing was performed to assess the support of clades. The combination of three data sets for numerous species has resulted in the most highly resolved and strongly supported topology yet obtained for angiosperms. In contrast to previous analyses based on single genes, much of the spine of the tree and most of the larger clades receive jackknife support 250%. Some of the noneudicots form a grade followed by a strongly supported eudicot clade. The early-branching angiosperms are Amborellaceae, Nymphaeaceae, and a clade of Austrobaileyaceae, Illiciaceae, and Schi-sandraceae. The remaining noneudicots, except Ceratophyllaceae, form a weakly supported core eumagnoliid clade comprising six well-supported subclades: Chloranthaceae, monocots, WinteraceaeICanellaceae, Piperales, Laurales, and Magnoliales. Ceratophyllaceae are sister to the eudicots. Within the well-supported eudicot clade, the early-diverging eudicots (e.g. Proteales, Ranunculales, Trochodendraceae, Sabiaceae) form a grade, followed by the core eudicots, the monophyly of which is also strongly supported. The core eudicots comprise six well-supported subclades: (1) Berberidopsidaceae/Aextoxicaceae; (2) Myrothamnaceae/ Gunneraceae; (3) Saxifragales, which are the sister to Vitaceae (including Leea) plus a strongly supported eurosid clade; (4) Santalales; (5) Caryophyllales, to which Dilleniaceae are sister; and (6) an asterid clade. The relationships among these six subclades of core eudicots do not receive strong support. This large data set has also helped place a number of enigmatic angiosperm families, including Podostemaceae, Aphloiaceae, and Ixerbaceae. This analysis further illustrates the tractability of large data sets and supports a recent, phylogenetically based, ordinal-level reclassification of the angiosperms based largely, but not exclusively, on molecular (DNA sequence) data. [source] Phylogeny of Syllidae (Polychaeta) based on combined molecular analysis of nuclear and mitochondrial genesCLADISTICS, Issue 6 2007M. Teresa Aguado The phylogeny of Syllidae is assessed in a combined analysis of molecular data from nuclear 18S rDNA and mitochondrial 16S rDNA and cytochrome c oxidase subunit I. In total, 103 terminal taxa are examined: 88 syllids in the four classical subfamilies Eusyllinae, Exogoninae, Syllinae and Autolytinae, as well as 15 outgroup taxa from Phyllodocida and Eunicida. Maximum parsimony analysis of the combined data set indicates that Syllidae, as currently delineated, is monophyletic, though not with very high support values. Astreptosyllis Kudenov & Dorsey, 1982, Streptosyllis Webster & Benedict, 1884 and SyllidesÖrsted, 1845 comprise a monophyletic group well differentiated from the rest of the Syllidae. The subfamilies Autolytinae and Syllinae are monophyletic. Exogoninae is monophyletic, although not well supported, and Eusyllinae is clearly paraphyletic. Results corroborate previous studies about the evolution of reproductive modes in that epigamy is the plesiomorphic condition and schizogamy appeared independently in Autolytinae and Syllinae. © The Willi Hennig Society 2007. [source] Phylogenetics, biogeography and classification of, and character evolution in, gamebirds (Aves: Galliformes): effects of character exclusion, data partitioning and missing dataCLADISTICS, Issue 6 2006Timothy M. Crowe The phylogenetic relationships, biogeography and classification of, and morpho-behavioral (M/B) evolution in, gamebirds (Aves: Galliformes) are investigated. In-group taxa (rooted on representatives of the Anseriformes) include 158 species representing all suprageneric galliform taxa and 65 genera. The characters include 102 M/B attributes and 4452 nucleic acid base pairs from mitochondrial cytochrome b (CYT B), NADH dehydrogenase subunit 2 (ND2), 12S ribosomal DNA (12S) and control region (CR), and nuclear ovomucoid intron G (OVO-G). Analysis of the combined character data set yielded a single, completely resolved cladogram that had the highest levels of jackknife support, which suggests a need for a revised classification for the phasianine galliforms. Adding 102 M/B characters to the combined CYT B and ND2 partitions (2184 characters) decisively overturns the topology suggested by analysis of the two mtDNA partitions alone, refuting the view that M/B characters should be excluded from phylogenetic analyses because of their relatively small number and putative character state ambiguity. Exclusion of the OVO-G partition (with >,70% missing data) from the combined data set had no effect on cladistic structure, but slightly lowered jackknife support at several nodes. Exclusion of third positions of codons in an analysis of a CYT B + ND2 partition resulted in a massive loss of resolution and support, and even failed to recover the monophyly of the Galliformes with jackknife support. A combined analysis of putatively less informative, "non-coding" characters (CYT B/ND2 third position sites + CR +12S + OVO-G sequences) yielded a highly resolved consensus cladogram congruent with the combined-evidence cladogram. Traditionally recognized suprageneric galliform taxa emerging in the combined cladogram are: the families Megapodiidae (megapodes), Cracidae (cracids), Numididae (guineafowls), Odontophoridae (New World quails) and Phasianidae (pheasants, pavonines, partridges, quails, francolins, spurfowls and grouse) and the subfamilies Cracinae (curassows, chachalacas and the horned guan), Penelopinae (remaining guans), Pavoninae sensu lato (peafowls, peacock pheasants and argus pheasants), Tetraoninae (grouse) and Phasianinae (pheasants minus Gallus). The monophyly of some traditional groupings (e.g., the perdicinae: partridges/quails/francolins) is rejected decisively, contrasted by the emergence of other unexpected groupings. The most remarkable phylogenetic results are the placement of endemic African galliforms as sisters to geographically far-distant taxa in Asia and the Americas. Biogeographically, the combined-data cladogram supports the hypothesis that basal lineages of galliforms diverged prior to the Cretaceous/Tertiary (K-T) Event and that the subsequent cladogenesis was influenced by the break-up of Gondwana. The evolution of gamebirds in Africa, Asia and the Americas has a far more complicated historical biogeography than suggested to date. With regard to character evolution: spurs appear to have evolved at least twice within the Galliformes; a relatively large number of tail feathers (, 14) at least three times; polygyny at least twice; and sexual dimorphism many times. © The Willi Hennig Society 2006. [source] Morphology versus molecules: resolution of the positions of Nymphalis, Polygonia, and related genera (Lepidoptera: Nymphalidae)CLADISTICS, Issue 3 2003Niklas Wahlberg The debate on whether to combine different data sets for simultaneous analysis has continued to the present day unabated. We have studied the effects of combining one morphological data set with four molecular data sets (two mitochondrial gene sequences and two nuclear gene sequences) for a group of butterflies belonging to the tribe Nymphalini using partitioned Bremer support. We particularly focus our attention on a group of species belonging to the genera Aglais, Inachis, Roddia, Nymphalis, Kaniska, and Polygonia. We find that, despite significant incongruence between most data partitions, all data partitions contribute positively to the support of most nodes in the most parsimonious trees found for the combined data set. We also find that the morphological data set resolves one particular node (Kaniska basal to Polygonia) with good support, while the molecular data sets are ambiguous about the existence of this node. We suggest that partitioned Bremer support allows one to critically appraise the robustness of each node in a given tree and thereby identify nodes that may change with the addition of new data and nodes that are likely to remain unchanged with new data. We also suggest that morphological data are still crucial to our being able to understand the relationships of extant organisms, despite published views to the contrary. Based on our results we suggest that Inachis should be synonymized with Aglais, Roddia with Nymphalis, and Kaniska with Polygonia. [source] Evacuation of pelleted feed and the suitability of titanium(IV) oxide as a feed marker for gut kinetics in Nile tilapiaJOURNAL OF FISH BIOLOGY, Issue 5 2003H. Richter The present study assessed the suitability of titanium(IV) oxide, TiO2, as a digesta passage marker in Nile tilapia Oreochromis niloticus and studied the shape of the evacuation curve in this species. In three separate trials, fish were given one dose of either 0·5, 0·25 or 0·1% of their body mass (% BME) of feed marked with 1% TiO2 or 0·5% BME of the same feed without marker. The fish were serially slaughtered at intervals after feeding and the stomach contents analysed for dry mass and marker content. The data for individual trials were analysed with the linear, square root, surface area and exponential evacuation models and parameter comparisons showed that, although the marker interfered slightly with the evacuation process, true meal size could be predicted more accurately from the marker data. The results of an analysis of the combined data sets suggested that stomach evacuation in this species is dependent more on food particle surface area (surface area model) than on stomach content mass (exponential model) as is generally assumed. On the basis of these results, it was concluded that TiO2 at an inclusion level of 1% is an acceptable marker for quantifying evacuation with a view to predicting food consumption but should be used with caution in digestibility studies. [source] Partitioned Bremer support and multiple treesCLADISTICS, Issue 4 2002Christine L. Lambkin Partitioned Bremer support (PBS) is a valuable means of assessing congruence in combined data sets, but some aspects require clarification. When more than one equally parsimonious tree is found during the constrained search for trees lacking the node of interest, averaging PBS for each data set across these trees can conceal conflict, and PBS should ideally be examined for each constrained tree. Similarly, when multiple most parsimonious trees (MPTs) are generated during analysis of the combined data, PBS is usually calculated on the consensus tree. However, extra information can be obtained if PBS is calculated on each of the MPTs or even suboptimal trees. [source] | |||||||||||||