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Different Orders (different + order)
Selected AbstractsCan distribution models help refine inventory-based estimates of conservation priority?DIVERSITY AND DISTRIBUTIONS, Issue 4 2010A case study in the Eastern Arc forests of Tanzania, Kenya Abstract Aim, Data shortages mean that conservation priorities can be highly sensitive to historical patterns of exploration. Here, we investigate the potential of regionally focussed species distribution models to elucidate fine-scale patterns of richness, rarity and endemism. Location, Eastern Arc Mountains, Tanzania and Kenya. Methods, Generalized additive models and land cover data are used to estimate the distributions of 452 forest plant taxa (trees, lianas, shrubs and herbs). Presence records from a newly compiled database are regressed against environmental variables in a stepwise multimodel. Estimates of occurrence in forest patches are collated across target groups and analysed alongside inventory-based estimates of conservation priority. Results, Predicted richness is higher than observed richness, with the biggest disparities in regions that have had the least research. North Pare and Nguu in particular are predicted to be more important than the inventory data suggest. Environmental conditions in parts of Nguru could support as many range-restricted and endemic taxa as Uluguru, although realized niches are subject to unknown colonization histories. Concentrations of rare plants are especially high in the Usambaras, a pattern mediated in models by moisture indices, whilst overall richness is better explained by temperature gradients. Tree data dominate the botanical inventory; we find that priorities based on other growth forms might favour the mountains in a different order. Main conclusions, Distribution models can provide conservation planning with high-resolution estimates of richness in well-researched areas, and predictive estimates of conservation importance elsewhere. Spatial and taxonomic biases in the data are essential considerations, as is the spatial scale used for models. We caution that predictive estimates are most uncertain for the species of highest conservation concern, and advocate using models and targeted field assessments iteratively to refine our understanding of which areas should be prioritised for conservation. [source] A complete boundary integral formulation for compressible Navier,Stokes equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2005Yang ZuoshengArticle first published online: 29 DEC 200 Abstract A complete boundary integral formulation for compressible Navier,Stokes equations with time discretization by operator splitting is developed using the fundamental solutions of the Helmholtz operator equation with different order. The numerical results for wall pressure and wall skin friction of two-dimensional compressible laminar viscous flow around airfoils are in good agreement with field numerical methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] Robust control from data via uncertainty model sets identificationINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 11 2004S. Malan Abstract In this paper an integrated robust identification and control design procedure is proposed. The plant to be controlled is supposed to be linear, time invariant, stable, possibly infinite dimensional and a set of noise-corrupted input,output measurements is supposed to be available. The emphasis is placed on the design of controllers guaranteeing robust stability and robust performances, and on the trade-off between controller complexity and achievable robust performances. First, uncertainty models are identified, consisting of parametric models of different order and tight frequency bounds on the magnitude of the unmodelled dynamics. Second, Internal Model Controllers, guaranteeing robust closed-loop stability and best approximating the ,perfect control' ideal target, are designed using H,/,-synthesis techniques. Then, the robust performances of the designed controllers are computed, allowing one to determine the level of model/controller complexity needed to guarantee desired closed-loop performances. Copyright © 2004 John Wiley & Sons, Ltd. [source] A joint study based on the electron localization function and catastrophe theory of the chameleonic and centauric models for the Cope rearrangement of 1,5-hexadiene and its cyano derivativesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 14 2005Victor Polo Abstract A novel interpretation of the chameleonic and centauric models for the Cope rearrangements of 1,5-hexadiene (A) and different cyano derivatives (B: 2,5-dicyano, C: 1,3,4,6-tetracyano, and D: 1,3,5-tricyano) is presented by using the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT) on the reaction paths calculated at the B3LYP/6-31G(d,p) level. The progress of the reaction is monitorized by the changes of the ELF structural stability domains (SSD), each being change controlled by a turning point derived from CT. The reaction mechanism of the parent reaction A is characterized by nine ELF SSDs. All processes occur in the vicinity of the transition structure and corresponding to a concerted formation/breaking of C1C6 and C3C4 bonds, respectively, together with an accumulation of charge density onto C2 and C5 atoms. Reaction B presents the same number of ELF SSDs as A, but a different order appears; the presence of 2,5-dicyano substituents favors the formation of C1C6 bonds over the breaking of C3C4 bond process, changing the reaction mechanism from a concerted towards a stepwise, via a cyclohexane biradical intermediate. On the other side, reaction C presents the same type of turning points but two ELF SSD less than A or B; there is an enhancement of the C3C4 bond breaking process at an earlier stage of the reaction by delocalizing the electrons from the C3C4 bond among the cyano groups. In the case of competitive effects of cyano subsituents on each moiety, as it is for reaction D, seven different ELF SSDs have been identified separated by eight turning points (two of them occur simultaneously). Both processes, formation/breaking of C1C6 and C3C4 bonds, are slightly favored with respect to the parent reaction (A), and the TS presents mixed electronic features of both B and C. The employed methodology provides theoretical support for the centauric nature (half-allyl, half-radical) for the TS of D. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1427,1437, 2005 [source] Variable number of tandem repeats in the growth hormone gene of Sparus aurata: association with growth and effect on gene transcriptionJOURNAL OF FISH BIOLOGY, Issue 2004R. Almuly The GH gene of Sparus aurata(saGH) contains variable number of tandem repeats (VNTR). The hyper-variable minisatellites in the first and third introns segregate in a Mendelian manner and exhibit numerous alleles. Analysis by PCR and sequencing of the two introns in several wild Sparidae species revealed comparable minisatellites with some variations. ,Zoo blot' with the first intron unit as a probe showed this sequence to be characteristic of several families from the Perciformes order. Unexpectedly, a similar minisatellite was found in the first intron of the GH gene in flounder, which belongs to a different order. Transfection of constructs containing a reporter gene and first intron of different length to four cell lines resulted in an inhibitory effect of the longer intron relative to the short intron. A (CA)n microsatellite (saGHpCA) is found in the GH promoter. A similar repeat at the same location is present in GH promoters of several other fish species. High variability (11 alleles) of the saGHpCA was found in a hatchery population. Full-sib family genotyping showed a Mendelian inheritance of these alleles. A significant association was found between allele distribution and body mass in large and average size fishes from a hatchery population. The intron minisatellites may serve as markers for hybrid population and parental assignment. Its presence in families and orders of the higher teleosts may help solving classification uncertainties. Their conservation and inhibitory effect suggest a biological role. The saGHpCA is correlated with growth and may be a good candidate for predicting growth performance. [source] Evaluation of glycosylation and malonylation patterns in flavonoid glycosides during LC/MS/MS metabolite profilingJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 5 2008P. Kachlicki Abstract Flavonoid conjugates constitute several classes of plant phenolic secondary metabolites including many isomeric compounds differing in the hydroxylation pattern and substitution of their rings with different groups such as alkyls, acyls or sugars. These compounds occur in plant tissues mainly as glycosides and in many cases it is necessary to have reliable and detailed information concerning the structure of these natural products. Our results were obtained using leaf extracts of Arabidopsis thaliana and Lupinus angustifolius in which different glycosides of flavones, flavonols and isoflavones are present. Analysis of collision-induced dissociation (CID)/MS/MS spectra of protonated [M + H]+, sodiated [M + Na]+ or deprotonated [M , H], molecules recorded during HPLC runs may bring needed information in this respect. However, registration of mass spectra of [M + Na]+ ions with a good efficiency is possible only after post-column addition of a sodium acetate solution to the LC column eluate. The retention of sodium cation on the saccharidic parts of the molecule is observed after the CID fragmentation. In many cases, the location of this cation on the glycan attached to C-3 hydroxyl group of flavonol led to assignment of its structure. Additionally, the determination of the structure of the aglycone and of the sequence of the glycan part was made possible through the CID data obtained from the [M + H]+ and [M , H], ions. CID spectra show a different order of sugar elimination from hydroxyl groups at C-3 and C-7 in flavonol glycosides isolated from A. thaliana leaves and give sufficient information to discriminate flavonoid O-diglycosides from flavonoid di-O-glycosides. Copyright © 2007 John Wiley & Sons, Ltd. [source] Components of Pink Snow Mould Resistance in Winter Wheat are Expressed Prior to Cold Hardening and in Detached LeavesJOURNAL OF PHYTOPATHOLOGY, Issue 3 2006Å. Ergon Abstract Resistance to pink snow mould, caused by Microdochium nivale, was investigated in four resistant winter wheat lines from the USDA World Cereal Collection (CI9342, CI14106, PI173440 and PI181268) and three Nordic wheat lines (Bjørke, Rida and V1004). Pink snow mould resistance was tested in non-hardened and cold-hardened plants incubated under artificial snow cover and in detached leaf segments mounted on water agar and incubated at either 3°C in darkness or at room temperature with light during the day. The wheat lines CI9342, CI14106 and PI181268 were more resistant than the Nordic lines, both before and after cold hardening. Thus, although cold hardening strongly increases the level of snow mould resistance in all the wheat lines, some resistance mechanisms are also present prior to cold hardening in some of the resistant lines. CI9342, CI14106 and PI181268 also had a higher level of resistance than the other lines in the detached leaf assay, indicating that these lines have some resistance mechanisms acting in the leaves. The resistance of PI173440 was expressed only in intact hardened plants and not in non-hardened plants or in detached leaves. This indicates that this line relies on cold hardening-related changes in the crown for its resistance. In the detached leaf assay the rate of lesion development varied greatly between leaves of different order. The highest correlation with the whole plant test was obtained when using secondary leaves and incubation at 3°C in the dark. [source] On variable bandwidth selection in local polynomial regressionJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 3 2000Kjell Doksum The performances of data-driven bandwidth selection procedures in local polynomial regression are investigated by using asymptotic methods and simulation. The bandwidth selection procedures considered are based on minimizing ,prelimit' approximations to the (conditional) mean-squared error (MSE) when the MSE is considered as a function of the bandwidth h. We first consider approximations to the MSE that are based on Taylor expansions around h=0 of the bias part of the MSE. These approximations lead to estimators of the MSE that are accurate only for small bandwidths h. We also consider a bias estimator which instead of using small h approximations to bias naïvely estimates bias as the difference of two local polynomial estimators of different order and we show that this estimator performs well only for moderate to large h. We next define a hybrid bias estimator which equals the Taylor-expansion-based estimator for small h and the difference estimator for moderate to large h. We find that the MSE estimator based on this hybrid bias estimator leads to a bandwidth selection procedure with good asymptotic and, for our Monte Carlo examples, finite sample properties. [source] Characterization of calcium-independent purinergic receptor-mediated apoptosis in hormone-refractory prostate cancerBJU INTERNATIONAL, Issue 3 2008Majid Shabbir OBJECTIVE To investigate the nature of purinergic signalling in hormone-refractory prostate cancer (HRPC) cells in vitro, as extracellular ATP inhibits the growth of HRPC in vitro via the activation of P2 purinergic receptors, and to characterize which P2 receptors subtypes and secondary mechanisms are involved. MATERIALS AND METHODS The effect of extracellular ATP on HRPC cell lines PC-3 and DU-145, and the normal prostate cell line PNT-2, were investigated. Reverse-transcription polymerase chain reaction was used to assess P2 purinergic receptors, which were pharmacologically characterized using various receptor agonists and antagonists. The effect of ATP on intracellular Ca2+ concentration ([Ca2+]i) was examined to asses its role in growth inhibition. The effect of combining ATP with the chemotherapeutic drug mitoxantrone was also assessed. RESULTS PC-3 cells expressed mRNA for P2X4,5,7, P2Y1,2,4,6; DU-145 cells expressed mRNA for P2X4,5, P2Y1,2,4,6,11; PNT-2 cells expressed mRNA for P2X4,5,7 and P2Y1,2,4,6,11. ATP (10,4m) inhibited HRPC PC-3 cell growth by ,,90%, an effect partially inhibited by the nonselective P2 receptor antagonists pyridoxal-5,-phosphate-6-azophenyl-2,,4, disulphonic acid (PPADS) and suramin. The order of potency of agonists was: adenosine 5,-O-(3 thiotriphosphate) > ATP > benzoyl benzoyl ATP >> 2-methylthio ATP. DU-145 cells responded similarly. Pharmacological profiling implicated P2X5 and/or P2Y11 receptors in the antineoplastic response in HRPC. ATP induced apoptosis in a [Ca2+]i -independent mechanism. ATP was significantly less effective on PNT-2 cells, which also had a different order of agonist potency. ATP combined with mitoxantrone in an additive manner in HRPC. CONCLUSIONS ATP effectively reduces growth of HRPC cells via calcium-independent apoptosis. Pharmacological profiling indicates P2X5 and/or P2Y11 receptors in this process, with a different functional purinergic receptor profile and sensitivity in normal vs cancer cells. [source] Phylogenetic relationships of Clematis (Ranunculaceae) based on chloroplast and nuclear DNA sequencesBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2006OSAMU MIIKEDA Phylogenetic relationships within Clematis, including Naravelia, Archiclematis and Clematopsis, were analysed using nucleotide sequences of chloroplast DNA [(1) matK and trnK introns; (2) atpB,rbcL spacer; (3) rpoB,trnC spacer; (4) psbA,trnH,trnQ spacer; (5) rbcL,accD spacer] and the nuclear ITS regions. The phylogenetic trees resulting from these analyses suggested nine major clades. The genera Archiclematis, Naravelia and Clematopsis were found to be nested within the genus Clematis, and should be included within it. Within the genus Clematis, the traditional subgenus Viorna was found to be monophyletic. The remaining subgenera (Flammula, Clematis and Campanella) and sections Flammula, Clematis and Cheiropsis, however, were found to be paraphyletic or polyphyletic. Recircumscription of several groups in Clematis was suggested. Enormous morphological diversification and very few nucleotide substitutions within Clematis indicate the recent radiation of the genus. Clematidinae shares a gene order with Anemoninae between the starting point of large single copy region and trnQ of chloroplast DNA, although Hepatica, a genus in Anemoninae, shows a different order in the region near trnH. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 152, 153,168. [source] Order of genetic events is critical determinant of aberrations in chromosome count and structureGENES, CHROMOSOMES AND CANCER, Issue 4 2004Christine Fauth A sequential acquisition of genetic events is critical in tumorigenesis. A key step is the attainment of infinite proliferative potential. Acquisition of this immortalization requires the activation of telomerase in addition to other activities, including inactivation of TP53 and the retinoblastoma family of tumor-suppressor proteins. However, the importance of the order in which these genetic events occur has not been established. To address this question, we used a panel of normal mammary fibroblasts and endothelial cultures that were immortalized after transduction with the catalytic subunit of telomerase (hTERT) and a temperature-sensitive mutant of the SV40 large-tumor (tsLT) oncoprotein in different orders in early- and late-passage stocks. These lines were maintained in continuous culture for up to 90 passages, equivalent to >300 population doublings (PDs) post-explantation during 3 years of continuous propagation. We karyotyped the cultures at different passages. Cultures that received hTERT first followed by tsLT maintained a near-diploid karyotype for more than 150 PDs. However, in late-passage stocks (>200 PDs), metaphase cells were mostly aneuploid. In contrast, the reverse order of gene transduction resulted in a marked early aneuploidy and chromosomal instability, already visible after 50 PDs. These results suggest that the order of genetic mutations is a critical determinant of chromosome count and structural aberration events. © 2004 Wiley-Liss, Inc. [source] Measuring and partitioning the high-order linkage disequilibrium by multiple order Markov chainsGENETIC EPIDEMIOLOGY, Issue 4 2008Yunjung Kim Abstract A map of the background levels of disequilibrium between nearby markers can be useful for association mapping studies. In order to assess the background levels of linkage disequilibrium (LD), multilocus LD measures are more advantageous than pairwise LD measures because the combined analysis of pairwise LD measures is not adequate to detect simultaneous allele associations among multiple markers. Various multilocus LD measures based on haplotypes have been proposed. However, most of these measures provide a single index of association among multiple markers and does not reveal the complex patterns and different levels of LD structure. In this paper, we employ non-homogeneous, multiple order Markov Chain models as a statistical framework to measure and partition the LD among multiple markers into components due to different orders of marker associations. Using a sliding window of multiple markers on phased haplotype data, we compute corresponding likelihoods for different Markov Chain (MC) orders in each window. The log-likelihood difference between the lowest MC order model (MC0) and the highest MC order model in each window is used as a measure of the total LD or the overall deviation from the gametic equilibrium for the window. Then, we partition the total LD into lower order disequilibria and estimate the effects from two-, three-, and higher order disequilibria. The relationship between different orders of LD and the log-likelihood difference involving two different orders of MC models are explored. By applying our method to the phased haplotype data in the ENCODE regions of the HapMap project, we are able to identify high/low multilocus LD regions. Our results reveal that the most LD in the HapMap data is attributed to the LD between adjacent pairs of markers across the whole region. LD between adjacent pairs of markers appears to be more significant in high multilocus LD regions than in low multilocus LD regions. We also find that as the multilocus total LD increases, the effects of high-order LD tends to get weaker due to the lack of observed multilocus haplotypes. The overall estimates of first, second, third, and fourth order LD across the ENCODE regions are 64, 23, 9, and 3%. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source] Estimating the number of independent components for functional magnetic resonance imaging dataHUMAN BRAIN MAPPING, Issue 11 2007Yi-Ou Li Abstract Multivariate analysis methods such as independent component analysis (ICA) have been applied to the analysis of functional magnetic resonance imaging (fMRI) data to study brain function. Because of the high dimensionality and high noise level of the fMRI data, order selection, i.e., estimation of the number of informative components, is critical to reduce over/underfitting in such methods. Dependence among fMRI data samples in the spatial and temporal domain limits the usefulness of the practical formulations of information-theoretic criteria (ITC) for order selection, since they are based on likelihood of independent and identically distributed (i.i.d.) data samples. To address this issue, we propose a subsampling scheme to obtain a set of effectively i.i.d. samples from the dependent data samples and apply the ITC formulas to the effectively i.i.d. sample set for order selection. We apply the proposed method on the simulated data and show that it significantly improves the accuracy of order selection from dependent data. We also perform order selection on fMRI data from a visuomotor task and show that the proposed method alleviates the over-estimation on the number of brain sources due to the intrinsic smoothness and the smooth preprocessing of fMRI data. We use the software package ICASSO (Himberg et al. [ 2004]: Neuroimage 22:1214,1222) to analyze the independent component (IC) estimates at different orders and show that, when ICA is performed at overestimated orders, the stability of the IC estimates decreases and the estimation of task related brain activations show degradation. Hum Brain Mapp, 2007. © 2007 Wiley-Liss, Inc. [source] Validation of interactive voice response system administration of the short inflammatory bowel disease questionnaireINFLAMMATORY BOWEL DISEASES, Issue 4 2009Manuel Y. Lam BA Abstract Background: The Short Inflammatory Bowel Disease Questionnaire (SIBDQ) is a written, self-administered instrument measuring quality of life in IBD. We assessed the validity of an interactive voice response system (IVRS) as a new mode of administering the SIBDQ. Methods: An IVRS was designed using prerecorded questions to collect data via touchtone telephone. Subjects with Crohn's disease (CD) or ulcerative colitis (UC) were randomized into 2 groups with different orders of administration: written, self-administered followed by IVRS (S-I) or IVRS followed by written, self-administered (I-S). Half of the S-I group was also randomized to receive a second IVRS. Sixty-four subjects were studied: 30 in S-I, 34 in I-S. Results: The mean SIBDQ scores were not different between written and IVRS modes (P = 0.26) with r = 0.93. IVRS scores were lower in active than inactive CD (36.1 ± 9.6 versus 54.7 ± 8.6, P < 0.001) and lower in active than inactive UC (40.8 ± 9.6 versus 59.8 ± 10.0, P < 0.001). Mean scores correlated highly with disease activity indices, and were not different between first and second IVRS administrations (P = 0.85) with r = 0.92. IVRS had excellent internal consistency (Cronbach alpha = 0.90). Conclusions: IVRS administration of the SIBDQ yields results similar to written self-administration, with excellent procedural validity, test,retest reliability, and internal consistency. (Inflamm Bowel Dis 2009) [source] Selection of locations of knots for linear splines in random regression test-day modelsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2010J. Jamrozik Summary Using spline functions (segmented polynomials) in regression models requires the knowledge of the location of the knots. Knots are the points at which independent linear segments are connected. Optimal positions of knots for linear splines of different orders were determined in this study for different scenarios, using existing estimates of covariance functions and an optimization algorithm. The traits considered were test-day milk, fat and protein yields, and somatic cell score (SCS) in the first three lactations of Canadian Holsteins. Two ranges of days in milk (from 5 to 305 and from 5 to 365) were taken into account. In addition, four different populations of Holstein cows, from Australia, Canada, Italy and New Zealand, were examined with respect to first lactation (305 days) milk only. The estimates of genetic and permanent environmental covariance functions were based on single- and multiple-trait test-day models, with Legendre polynomials of order 4 as random regressions. A differential evolution algorithm was applied to find the best location of knots for splines of orders 4 to 7 and the criterion for optimization was the goodness-of-fit of the spline covariance function. Results indicated that the optimal position of knots for linear splines differed between genetic and permanent environmental effects, as well as between traits and lactations. Different populations also exhibited different patterns of optimal knot locations. With linear splines, different positions of knots should therefore be used for different effects and traits in random regression test-day models when analysing milk production traits. [source] Multivariate analyses of carcass traits for Angus cattle fitting reduced rank and factor analytic modelsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2007K. Meyer Summary Multivariate analyses of carcass traits for Angus cattle, consisting of six traits recorded on the carcass and eight auxiliary traits measured by ultrasound scanning of live animals, are reported. Analyses were carried out by restricted maximum likelihood, fitting a number of reduced rank and factor analytic models for the genetic covariance matrix. Estimates of eigenvalues and eigenvectors for different orders of fit are contrasted and implications for the estimates of genetic variances and correlations are examined. Results indicate that at most eight principal components (PCs) are required to model the genetic covariance structure among the 14 traits. Selection index calculations suggest that the first seven of these PCs are sufficient to obtain estimates of breeding values for the carcass traits without loss in the expected accuracy of evaluation. This implied that the number of effects fitted in genetic evaluation for carcass traits can be halved by estimating breeding values for the leading PCs directly. [source] Primers from the orders Osteoglossiform and Siluriform detect polymorphic microsatellite loci in sun-catfish, Horabagrus brachysoma (Teleostei: Bagridae)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006A. Gopalakrishnan Summary Horabagrus brachysoma (sun-catfish, Bagridae, Siluriformes) is a valuable ornamental and food fish. The stock structure of H. brachysoma, necessary to conserve its declining natural populations, is not known. Twenty-five primers developed for four fish species belonging to the orders Siluriform (3) and Osteoglossiform (1) were tested and eight primers amplified microsatellite loci in H. brachysoma. The results demonstrate that cross-priming between fish species belonging to different families and even to different orders can yield microsatellite loci. Five of eight primers each amplified two loci. However, the loci that had repeat motifs after sequencing were considered only for genotyping. Finally, eight loci were polymorphic with hree to seven alleles. Individual fish genotype data (n = 42; 21 each in two rivers) at each locus was analysed. Significant genetic heterogeneity was detected at six loci. The identified loci exhibited potential for use in population genetics application in H. brachysoma. [source] Invasive mutualisms and the structure of plant,pollinator interactions in the temperate forests of north-west Patagonia, ArgentinaJOURNAL OF ECOLOGY, Issue 1 2006CAROLINA L. MORALES Summary 1Alien species may form plant,animal mutualistic complexes that contribute to their invasive potential. Using multivariate techniques, we examined the structure of a plant,pollinator web comprising both alien and native plants and flower visitors in the temperate forests of north-west Patagonia, Argentina. Our main objective was to assess whether plant species origin (alien or native) influences the composition of flower visitor assemblages. We also examined the influence of other potential confounding intrinsic factors such as flower symmetry and colour, and extrinsic factors such as flowering time, site and habitat disturbance. 2Flowers of alien and native plant species were visited by a similar number of species and proportion of insects from different orders, but the composition of the assemblages of flower-visiting species differed between alien and native plants. 3The influence of plant species origin on the composition of flower visitor assemblages persisted after accounting for other significant factors such as flowering time, bearing red corollas, and habitat disturbance. This influence was at least in part determined by the fact that alien flower visitors were more closely associated with alien plants than with native plants. The main native flower visitors were, on average, equally associated with native and alien plant species. 4In spite of representing a minor fraction of total species richness (3.6% of all species), alien flower visitors accounted for > 20% of all individuals recorded on flowers. Thus, their high abundance could have a significant impact in terms of pollination. 5The mutualistic web of alien plants and flower-visiting insects is well integrated into the overall community-wide pollination web. However, in addition to their use of the native biota, invasive plants and flower visitors may benefit from differential interactions with their alien partners. The existence of these invader complexes could contribute to the spread of aliens into novel environments. [source] HOST PARASITE INTERACTIONS BETWEEN FRESHWATER PHYTOPLANKTON AND CHYTRID FUNGI (CHYTRIDIOMYCOTA),JOURNAL OF PHYCOLOGY, Issue 3 2004Bas W. Ibelings Some chytrids are host-specific parasiticfungithat may have a considerable impact on phytoplankton dynamics. The phylum Chytridiomycota contains one class, the Chytridiomycetes, and is composed of five different orders. Molecular studies now firmly place the Chytridiomycota within the fungal kingdom. Chytrids are characterized by having zoospores, a motile stage in their life cycle. Zoospores are attracted to the host cell by specific signals. No single physical,chemical factor has been found that fully explains the dynamics of chytrid epidemics in the field. Fungal periodicity was primarily related to host cell density. The absence of aggregated distributions of chytrids on their hosts suggested that their hosts did not vary in their susceptibility to infection. A parasite can only become epidemic when it grows faster than the host. Therefore, it has been suggested that epidemics in phytoplankton populations arise when growth conditions for the host are unfavorable. No support for such a generalization was found, however. Growth of the parasitic fungus Rhizophydium planktonicum Canter emend, parasitic on the diatom Asterionella formosa Hassal, was reduced under stringent nutrient limitation,because production and infectivity of zoospores were affected negatively. A moderate phosphorous or light limitation favored epidemic development, however. Chytrid infections have been shown to affect competition between their algal hosts and in this way altered phytoplankton succession. There is potential for coevolution between Asterionella and the chytrid Zygorhizidium planktonicum Canter based on clear reciprocal fitness costs, absence of overall infective parasite strains, and possibly a genetic basis for host susceptibility and parasite infectivity. [source] The effect of observations on Bayesian choice of an autoregressive modelJOURNAL OF TIME SERIES ANALYSIS, Issue 1 2006K. D. S. Young Abstract., We consider the effect, on a Bayes factor, of omitting observations in time-series models. In particular, we study a Bayes factor for deciding between autoregressive models of different orders. Throughout we use Gibbs sampling to estimate the parameters of the models and the marginal densities. We illustrate the methods using data generated from an autoregressive model and some data on bag snatching in the Hyde Park area of Chicago. [source] Study on the Kinetics for Enzymatic Degradation of a Natural Polysaccharide, Konjac GlucomannanMACROMOLECULAR SYMPOSIA, Issue 1 2004Guangji Li Abstract The enzymatic degradation of konjac glucomannan (KGM) was conducted using ,-mannanase from an alkalophilic Bacillus sp. in the aqueous medium (pH 9.0) at 30°C. The intrinsic viscosity ([,]), molecular weight (Mw) and molecular weight distribution (MWD) of the degraded KGM were measured. The mathematical relation between [,] and Mw, [,] = 5.06 × 10,4Mw0.754, was established. The kinetic analysis reveals a dependence of the rate constant (k) on the period of reaction and the initial substrate concentration (c0) over the range of substrate concentration (1.0,2.0%) used in this work. The results indicate that the enzymatic degradation of KGM is a complex reaction combining two reaction processes with different orders. In the initial phase of degradation k is inversely proportional to c0, which is characteristic of a zeroth-order reaction; while in the following phase k is independent of c0, implying the degradation follows a first-order reaction. The reactivity difference in breakable linkages of KGM, the action mechanism of an enzyme on KGM macromolecules, and the theory concerning the formation of an enzyme-substrate complex and ,substrate saturation' can be used to explain such a kinetic behavior. In addition, the enzymatic degradation of KGM was also carried out using the other enzymes like ,-mannanase from a Norcardioform actinomycetes, ,-glucanase Finizym and a compound enzyme Hemicell as a biocatalyst. By comparing and analyzing the degradation processes of KGM catalyzed by four different enzymes, it can be observed that there is a two-stage reaction with two distinct kinetic regimes over a certain range of degradation time for each of the degradation processes. These results are useful to realize controllable degradation of polysaccharides via an environmental benign process. [source] Mixed species groups in mammalsMAMMAL REVIEW, Issue 3-4 2003EVA STENSLAND ABSTRACT 1.,Mixed species groups have long been noted in birds, but they also occur among different species of mammals ranging from closely related species to species from different orders. Mixed species groups of mammals occur in many different habitats, e.g. ungulates on the savannah, primates in various types of forests and cetaceans in the oceans. Mixed species groups are very different in their duration, frequency, predominant activity and structure depending on the species interacting and the habitat they occur in. 2.,Functional explanations for mixed species groups usually fall within two categories: foraging advantages and predator avoidance. However, there could also be other social and reproductive advantages of mixed species groups that could contribute to their formation and stability. The advantages do not have to be equally distributed between the participating species and can also vary according to season and the presence of predators. 3.,It is important that all investigators of mixed species groups take their studies one step further after the naturalistic description and test the function and benefits of mixed species groups in order to give more strength to their conclusions. In this paper we review and discuss the function of mixed species groups in mammals and suggest an approach on how to investigate the function of such groups. [source] Purring and similar vocalizations in mammalsMAMMAL REVIEW, Issue 4 2002G. Peters ABSTRACT The terms purr and purring have been used for vocalizations produced by a variety of mammalian species in different orders. A few other mammalian vocalizations that are structurally somewhat similar to felid purring but have been given another term have also been described in the literature. Because use of the same term implies ,sameness', which in an evolutionary sense can only mean that the vocalizations so named are homologous (= share the same ancestral vocalization type), the terms purr and purring ought to be restricted to vocalizations homologous with felid purring, and any mammalian vocalization homologous with felid purring ought to be named accordingly. According to present knowledge ,true' purring is established only in the families Viverridae and Felidae of the Carnivora. Vocalizations very similar in structure occur in matching behavioural contexts in other families of the Carnivora and several other mammalian orders. Most of these vocalization types are likely to have evolved convergently. [source] An algebraic generalization of local Fourier analysis for grid transfer operators in multigrid based on Toeplitz matricesNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 2-3 2010M. Donatelli Abstract Local Fourier analysis (LFA) is a classical tool for proving convergence theorems for multigrid methods (MGMs). In particular, we are interested in optimal convergence, i.e. convergence rates that are independent of the problem size. For elliptic partial differential equations (PDEs), a well-known optimality result requires that the sum of the orders of the grid transfer operators is not lower than the order of the PDE approximated. Analogously, when dealing with MGMs for Toeplitz matrices, a well-known optimality condition concerns the position and the order of the zeros of the symbols of the grid transfer operators. In this work we show that in the case of elliptic PDEs with constant coefficients, the two different approaches lead to an equivalent condition. We argue that the analysis for Toeplitz matrices is an algebraic generalization of the LFA, which allows to deal not only with differential problems but also for instance with integral problems. The equivalence of the two approaches gives the possibility of using grid transfer operators with different orders also for MGMs for Toeplitz matrices. We give also a class of grid transfer operators related to the B-spline's refinement equation and study their geometric properties. Numerical experiments confirm the correctness of the proposed analysis. Copyright © 2010 John Wiley & Sons, Ltd. [source] Insecticidal activity of scorpion toxin (ButaIT) and snowdrop lectin (GNA) containing fusion proteins towards pest species of different ordersPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 1 2010Elaine C Fitches Abstract BACKGROUND: The toxicity of a fusion protein, ButalT/GNA, comprising a venom toxin (ButaIT) derived from the red scorpion, Mesobuthus tamulus (F.), and Galanthus nivalis agglutinin (GNA), was evaluated under laboratory conditions against several pest insects. Insecticidal activity was compared with SFI1/GNA, a fusion comprising a venom toxin (SFI1) derived from the European spider Segestria florentina (Rossi) and GNA, which has been previously demonstrated to be effective against lepidopteran and hemipteran pests, and to GNA itself. RESULTS: Injection assays demonstrated that both fusion proteins were toxic to lepidopteran larvae, dipteran adults, coleopteran adults and larvae and dictyopteran nymphs. ButalT/GNA was more toxic than SFI1/GNA in all cases. GNA itself made a minor contribution to toxicity. Oral toxicity of ButalT/GNA towards lepidopteran pests was confirmed against neonate Spodoptera littoralis (Boisd.), where incorporation at 2% dietary protein resulted in 50% mortality and > 85% reduction in growth compared with controls. ButaIT/GNA was orally toxic to Musca domestica L. adults, causing 75% mortality at 1 mg mL,1 in aqueous diets and, at 2 mg g,1 it was orally toxic to Tribolium castaneum (Herbst.), causing 60% mortality and a 90% reduction in growth. CONCLUSIONS: Toxicity of the ButaIT/GNA recombinant fusion protein towards a range of insect pests from different orders was demonstrated by injection bioassays. Feeding bioassays demonstrated the potential use of the ButaIT/GNA fusion protein as an orally active insecticide against lepidopteran, dipteran and coleopteran pests. These experiments provide further evidence that the development of fusion protein technology for the generation of new, biorational, anti-insect molecules holds significant promise. © Crown Copyright 2009. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] Flexibility improvement of epoxy resin by liquid rubber modificationPOLYMER INTERNATIONAL, Issue 9 2002C Kaynak Abstract The objective of this study was to improve the flexibility of diglycidyl ether of bisphenol-A based epoxy resin by using a liquid rubber. For this purpose, hydroxyl terminated polybutadiene (HTPB) was used at two concentrations of 1,% and 1.5,% by weight. In order to improve compatibility between liquid rubber and epoxy, a silane coupling agent (SCA) was also used. Bending test specimens were moulded by using four different orders of mixing of HTPB with SCA and hardener to investigate the compatibility of HTPB and epoxy matrix. Three-point bending tests indicated that the specimens containing HTPB rubber had higher flexibility than neat epoxy specimens. Moreover, liquid rubber modification resulted in increased plastic strain at failure due to the possible decrease in crosslinking density with the change in reactions path. Fractographic examinations under scanning electron microscope indicated the formation of rubber domains in the epoxy matrix. The deformed rubber domains and increased incidence of deformation lines, especially in the third and fourth group specimens, assessed the improvement in flexibility. © 2002 Society of Chemical Industry [source] Embedded Stochastic Runge-Kutta MethodsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Andreas Rößler We present some new embedded explicit stochastic Runge-Kutta methods for the approximation of Stratonovich stochastic differential equations in the weak sense with different orders of convergence. The presented methods yield an estimate of the local error which can be used for a step size control algorithm. [source] Productions of social solidarity and of social compulsion,PSYCHOTHERAPY AND POLITICS INTERNATIONAL, Issue 2 2006Janine Puget Abstract I begin from the assumption that the social groups within which people acquire subjective attributes belong to two different orders. Those of the first order follow the model of organized, closed structures that define fixed places. Examples are social institutions, the state, and the oedipal structure. The groups of the second order are ad hoc groups whose life and consistency depend on the emergence of a problem that must be solved and, therefore, on a doing together. I call these groups communities. This approach to the matter of globalization responds to a way of thinking linkage organization that privileges different ontologies and a characteristic topology for each of them. We should ask ourselves whether solidarity requires an ontological definition; whether it constitutes an ethical problem (commitment), a moral problem (behaviour or obligation), an action/doing based on a previous knowledge of one of the parties, a practice created in connection with an emerging problem, a psychic mechanism, and so on. To answer these manifold questions, I travel a path , one among many possible paths , that involves understanding solidarity as a resource and a practice referred to psychic suffering, especially in present-day Argentina. Copyright © 2006 John Wiley & Sons. Ltd. [source] Policy Networks and Policy Learning UK Economic Policy in the 1960s and 1970sPUBLIC ADMINISTRATION, Issue 4 2000Hugh Pemberton Policy networks are advanced as an alternative to the Westminster model of the UK polity but the theory lacks an internal dynamic and has typological problems. This article applies Peter Hall's (1993) concept of ,social learning' to policy networks and maps the networks found in two case studies of British economic policy making: Hall's own study of the shift from Keynesianism to monetarism in the 1970s and the author's research on the advent of ,Keynesian-plus' in the early 1960s. The article advances three main propositions. Firstly, that integrating the concept of social learning can dynamize the policy network model. Secondly, the case studies suggest that different network configurations are associated with different orders of policy change but that Hall's definition of ,third order change' may be too restrictive. Thirdly, policy networks can be much more complex and fluid then is generally claimed, sometimes becoming so extensive that they might be termed a ,meta-network'. [source] The causal agents of ,entomophthoramycosis' belong to two different orders: a suggestion for modification of the clinical nomenclatureCLINICAL MICROBIOLOGY AND INFECTION, Issue 3 2005A. B. Jensen No abstract is available for this article. [source] | |||||||||||||||||||||||||||||||