4,940 research outputs found

    Molecular phylogeny of brachiopods and phoronids based on nuclear-encoded small subunit ribosomal RNA gene sequences

    Get PDF
    Brachiopod and phoronid phylogeny is inferred from SSU rDNA sequences of 28 articulate and nine inarticulate brachiopods, three phoronids, two ectoprocts and various outgroups, using gene trees reconstructed by weighted parsimony, distance and maximum likelihood methods. Of these sequences, 33 from brachiopods, two from phoronids and one each from an ectoproct and a priapulan are newly determined. The brachiopod sequences belong to 31 different genera and thus survey about 10% of extant genus-level diversity. Sequences determined in different laboratories and those from closely related taxa agree well, but evidence is presented suggesting that one published phoronid sequence (GenBank accession UO12648) is a brachiopod-phoronid chimaera, and this sequence is excluded from the analyses. The chiton, Acanthopleura, is identified as the phenetically proximal outgroup; other selected outgroups were chosen to allow comparison with recent, non-molecular analyses of brachiopod phylogeny. The different outgroups and methods of phylogenetic reconstruction lead to similar results, with differences mainly in the resolution of weakly supported ancient and recent nodes, including the divergence of inarticulate brachiopod sub-phyla, the position of the rhynchonellids in relation to long- and short-looped articulate brachiopod clades and the relationships of some articulate brachiopod genera and species. Attention is drawn to the problem presented by nodes that are strongly supported by non-molecular evidence but receive only low bootstrap resampling support. Overall, the gene trees agree with morphology-based brachiopod taxonomy, but novel relationships are tentatively suggested for thecideidine and megathyrid brachiopods. Articulate brachiopods are found to be monophyletic in all reconstructions, but monophyly of inarticulate brachiopods and the possible inclusion of phoronids in the inarticulate brachiopod clade are less strongly established. Phoronids are clearly excluded from a sister-group relationship with articulate brachiopods, this proposed relationship being due to the rejected, chimaeric sequence (GenBank UO12648). Lineage relative rate tests show no heterogeneity of evolutionary rate among articulate brachiopod sequences, but indicate that inarticulate brachiopod plus phoronid sequences evolve somewhat more slowly. Both brachiopods and phoronids evolve slowly by comparison with other invertebrates. A number of palaeontologically dated times of earliest appearance are used to make upper and lower estimates of the global rate of brachiopod SSU rDNA evolution, and these estimates are used to infer the likely divergence times of other nodes in the gene tree. There is reasonable agreement between most inferred molecular and palaeontological ages. The estimated rates of SSU rDNA sequence evolution suggest that the last common ancestor of brachiopods, chitons and other protostome invertebrates (Lophotrochozoa and Ecdysozoa) lived deep in Precambrian time. Results of this first DNA-based, taxonomically representative analysis of brachiopod phylogeny are in broad agreement with current morphology-based classification and systematics and are largely consistent with the hypothesis that brachiopod shell ontogeny and morphology are a good guide to phylogeny

    Ruimte voor Biodiversiteit

    Get PDF
    Duurzame ontwikkeling van de Groene en Blauwe Ruimte in een veranderende wereld. Dat is het centrale thema van het kennisbasis onderzoekprogramma KB1. De groene en blauwe ruimte vormen bij uitstek het Wagenings domein. Het onderzoek is gericht op zowel Nederland als op deltagebieden elders in de wereld. Aan de hand van ontwikkelingen rond landgebruik, verstedelijking, klimaat, maatschappelijke organisatie en besluitvorming wordt nagegaan welke kennisvragen er leven over de groen-blauwe ruimte en hoe men deze vragen met een wetenschappelijke aanpak kan beantwoorden

    The effects of dietary fibre type on satiety-related hormones and voluntary food intake in dogs

    Get PDF
    Depending on type and inclusion level, dietary fibre may increase and maintain satiety and postpone the onset of hunger. This 7-week study evaluated the effect of fibre fermentability on physiological satiety-related metabolites and voluntary food intake (VFI) in dogs. Sixteen healthy adult dogs were fed a low-fermentable fibre (LFF) diet containing 8·5 % cellulose or a high-fermentable fibre (HFF) diet containing 8·5 % sugarbeet pulp and 2 % inulin. Large intestinal fibre degradation was evaluated by apparent faecal digestibility of nutrients and faecal SCFA and NH3 concentrations. Postprandial blood samples were obtained to determine postprandial plasma glucose, insulin, total peptide tyrosine–tyrosine (PYY), total glucagon-like peptide-1 (GLP-1) and total ghrelin concentrations. At the end of the study, the dogs were given a single meal of a dry dog food to determine VFI. Dogs fed the HFF diet had a significantly higher large intestinal fibre degradation and production of SCFA compared with the dogs fed the LFF diet. The HFF-fed dogs tended (P = 0·058) to show a lower VFI at the end of the study. No treatment effects were found for postprandial plasma glucose, PYY, GLP-1 and ghrelin responses. The concentrations of these metabolites could not be related to the observed difference in VFI. The inclusion of fermentable fibre in canine diets may contribute to the prevention or mitigation of obesity through its effects on satiety. The underlying mechanisms require further investigatio

    Children's Pronoun Interpretation Problems Are Related to Theory of Mind and Inhibition, But Not Working Memory

    Get PDF
    In several languages, including English and Dutch, children’s acquisition of the interpretation of object pronouns (e.g., him) is delayed compared to that of reflexives (e.g., himself). Various syntactic and pragmatic explanations have been proposed to account for this delay in children’s acquisition of pronoun interpretation. This study aims to provide more insight into this delay by investigating potential cognitive mechanisms underlying this delay. Dutch-speaking children between 6 and 12 years old with autism spectrum disorder (ASD; n = 47), attention-deficit/hyperactivity disorder (ADHD; n = 36) or typical development (TD; n = 38) were tested on their interpretation and production of object pronouns and reflexives and on theory of mind, working memory, and response inhibition. It was found that all three groups of children had difficulty with pronoun interpretation and that their performance on pronoun interpretation was associated with theory of mind and inhibition. These findings support an explanation of object pronoun interpretation in terms of perspective taking, according to which listeners need to consider the speaker’s perspective in order to block coreference between the object pronoun and the subject of the same sentence. Unlike what is predicted by alternative theoretical accounts, performance on pronoun interpretation was not associated with working memory, and the children made virtually no errors in their production of object pronouns. As the difficulties with pronoun interpretation were similar for children with ASD, children with ADHD and typically developing children, this suggests that certain types of perspective taking are unaffected in children with ASD and ADHD

    Projected free energies for polydisperse phase equilibria

    Full text link
    A `polydisperse' system has an infinite number of conserved densities. We give a rational procedure for projecting its infinite-dimensional free energy surface onto a subspace comprising a finite number of linear combinations of densities (`moments'), in which the phase behavior is then found as usual. If the excess free energy of the system depends only on the moments used, exact cloud, shadow and spinodal curves result; two- and multi-phase regions are approximate, but refinable indefinitely by adding extra moments. The approach is computationally robust and gives new geometrical insights into the thermodynamics of polydispersity.Comment: 4 pages, REVTeX, uses multicol.sty and epsf.sty, 1 postscript figure include

    BAMBOO for Refugees—A culturally sensitive positive psychology intervention:A protocol for a pilot Randomized Controlled Trial

    Get PDF
    This protocol investigates the efficacy of a mental health and psychosocial support (MHPSS) program named BAMBOO. The goal of this program is to increase resilience and mental well-being among refugees. In recent years, there has been an increasing number of refugees fleeing to Europe and applying for permanent residence. In the Netherlands, a wide variety of programs that focus on increasing mental well-being among refugees is available. BAMBOO is a strengths-based intervention, which consists of five weekly two-hour group-based sessions. It is based on the theoretical framework of positive psychology and adapted according to the guidelines for the implementation of culturally sensitive cognitive behavioral therapy among refugees. The program does not focus on the treatment of trauma, mental disorders, or underlying problems, but aims to increase factors such as personal strengths, positive emotions, positive relations, and self-esteem. The first version of the program (BAMBOO 1.0) has been conducted at over 50 asylum centers in the Netherlands since January 2020. In the time period from September 2020 to September 2022, qualitative and quantitative data were collected among BAMBOO trainers and participants and the program was adapted, leading to a revised version (BAMBOO 2.0). A single-blinded parallel pilot randomized controlled trial, with an intervention group and awaiting list control group, with 34 participants per group will be used to test the program’s efficacy. Outcomes include resilience, satisfaction with life, positive and negative affect, and self-esteem. The study will be conducted among adult Arabic speaking refugees, residing at an asylum center in the Netherlands and/ or in a Dutch municipality, Baseline, post-intervention, and five-week follow-up assessments will be conducted. This paper describes the protocol for the evaluation of a novel and culturally adapted program. The study will shed light on the efficacy of a culturally sensitive strengths-based intervention as a preventive approach to increase refugee well-bein
    • …
    corecore