382 research outputs found

    Supercritical multitype branching processes: the ancestral types of typical individuals

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    For supercritical multitype branching processes in continuous time, we investigate the evolution of types along those lineages that survive up to some time t. We establish almost-sure convergence theorems for both time and population averages of ancestral types (conditioned on non-extinction), and identify the mutation process describing the type evolution along typical lineages. An important tool is a representation of the family tree in terms of a suitable size-biased tree with trunk. As a by-product, this representation allows a `conceptual proof' (in the sense of Kurtz, Lyons, Pemantle, Peres 1997) of the continuous-time version of the Kesten-Stigum theorem.Comment: 23 pages, 1 figure; minor additions, added reference

    Whole genome sequencing and microsatellite analysis of the Plasmodium falciparum E5 NF54 strain show that the var, rifin and stevor gene families follow Mendelian inheritance

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    Background: Plasmodium falciparum exhibits a high degree of inter-isolate genetic diversity in its variant surface antigen (VSA) families: P. falciparum erythrocyte membrane protein 1, repetitive interspersed family (RIFIN) and subtelomeric variable open reading frame (STEVOR). The role of recombination for the generation of this diversity is a subject of ongoing research. Here the genome of E5, a sibling of the 3D7 genome strain is presented. Short and long read whole genome sequencing (WGS) techniques (Ilumina, Pacific Bioscience) and a set of 84 microsatellites (MS) were employed to characterize the 3D7 and non-3D7 parts of the E5 genome. This is the first time that VSA genes in sibling parasites were analysed with long read sequencing technology. Results: Of the 5733 E5 genes only 278 genes, mostly var and rifin/stevor genes, had no orthologues in the 3D7 genome. WGS and MS analysis revealed that chromosomal crossovers occurred at a rate of 0–3 per chromosome. var, stevor and rifin genes were inherited within the respective non-3D7 or 3D7 chromosomal context. 54 of the 84 MS PCR fragments correctly identified the respective MS as 3D7- or non-3D7 and this correlated with var and rifin/stevor gene inheritance in the adjacent chromosomal regions. E5 had 61 var and 189 rifin/stevor genes. One large non-chromosomal recombination event resulted in a new var gene on chromosome 14. The remainder of the E5 3D7-type subtelomeric and central regions were identical to 3D7. Conclusions: The data show that the rifin/stevor and var gene families represent the most diverse compartments of the P. falciparum genome but that the majority of var genes are inherited without alterations within their respective parental chromosomal context. Furthermore, MS genotyping with 54 MS can successfully distinguish between two sibling progeny of a natural P. falciparum cross and thus can be used to investigate identity by descent in field isolates

    A study of candidate genes for day blindness in the standard wire haired dachshund

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    <p>Abstract</p> <p>Background</p> <p>A genetic study was performed to identify candidate genes associated with day blindness in the standard wire haired dachshund. Based on a literature review of diseases in dogs and human with phenotypes similar to day blindness, ten genes were selected and evaluated as potential candidate genes associated with day blindness in the breed.</p> <p>Results</p> <p>Three of the genes, <it>CNGB3</it>, <it>CNGA3 </it>and <it>GNAT2</it>, involved in cone degeneration and seven genes and loci, <it>ABCA4</it>, <it>RDH5</it>, <it>CORD8</it>, <it>CORD9</it>, <it>RPGRIP1</it>, <it>GUCY2D </it>and <it>CRX</it>, reported to be involved in cone-rod dystrophies were studied. Polymorphic markers at each of the candidate loci were studied in a family with 36 informative offspring. The study revealed a high frequency of recombinations between the candidate marker alleles and the disease.</p> <p>Conclusion</p> <p>Since all of the markers were at the exact position of the candidate loci, and several recombinations were detected for each of the loci, all ten genes were excluded as causal for this canine, early onset cone-rod dystrophy. The described markers may, however, be useful to screen other canine resource families segregating eye diseases for association to the ten genes.</p

    Anaphylatoxin C5a receptor mRNA is strongly expressed in Kupffer and stellate cells and weakly in sinusoidal endothelial cells but not in hepatocytes of normal rat liver

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    AbstractAnaphylatoxins (C5a and C3a), which are generated during complement activation, have recently been shown to increase glucose output from hepatocytes (HC) in perfused rat liver. They did not act directly on HC but indirectly by prostanoid release from non-parenchymal cells (NPC), probably Kupffer cells (KC). In order to corroborate this mechanism, the distribution of anaphylatoxin receptors in the different cell types of rat liver was determined by quantitative RT-PCR with primers specific for the rat C5a receptor (rC5aR) using RNA isolated from KC, sinusoidal endothelial cells (SEC), hepatic stellate cells (HSC) and HC. In line with functional data, C5aR mRNA was detected in freshly isolated NPC but not in HC of rat liver. Mainly KC but also HSC clearly expressed C5aR mRNA, while SEC did so only weakly. KC expressed up to 10-fold more C5aR mRNA than HSC and these in turn up to 10-fold more than SEC. These results support the proposed indirect action of anaphylatoxins on HC

    How Old is the Universe?

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    We present a teaching unit that offers the students the opportunity to discover the age of the universe by hands on model experiments also with applets. We present a novel software, worksheets and outlines of lessons. We present experiences with students and a teacher training

    How Old is the Universe?

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    We present a teaching unit that offers the students the opportunity to discover the age of the universe by hands on model experiments also with applets. We present a novel software, worksheets and outlines of lessons. We present experiences with students and a teacher training

    Coagulopathy management of multiple injured patients – a comprehensive literature review of the European guideline 2019

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    The European guideline on the management of trauma-induced major bleeding and coagulopathy summarises the most relevant recommendations for trauma coagulopathy management.center dot The management of trauma-induced major bleeding should interdisciplinary follow algorithms which distinguish between life-threatening and non-life-threatening bleeding.center dot Point-of-care viscoelastic methods (VEM) assist target-controlled haemostatic treatment. Neither conventional coagulation assays nor VEM should delay treatment in life-threatening trauma-induced bleeding.center dot Adjustments may be rational due to local circumstances, including the availability of blood products, pharmaceuticals, and employees

    Targeted disruption of py235ebp-1: Invasion of erythrocytes by Plasmodium yoelii using an alternative Py235 erythrocyte binding protein

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    Plasmodium yoelii YM asexual blood stage parasites express multiple members of the py235 gene family, part of the super-family of genes including those coding for Plasmodium vivax reticulocyte binding proteins and Plasmodium falciparum RH proteins. We previously identified a Py235 erythrocyte binding protein (Py235EBP-1, encoded by the PY01365 gene) that is recognized by protective mAb 25.77. Proteins recognized by a second protective mAb 25.37 have been identified by mass spectrometry and are encoded by two genes, PY01185 and PY05995/PY03534. We deleted the PY01365 gene and examined the phenotype. The expression of the members of the py235 family in both the WT and gene deletion parasites was measured by quantitative RT-PCR and RNA-Seq. py235ebp-1 expression was undetectable in the knockout parasite, but transcription of other members of the family was essentially unaffected. The knockout parasites continued to react with mAb 25.77; and the 25.77-binding proteins in these parasites were the PY01185 and PY05995/PY03534 products. The PY01185 product was also identified as erythrocyte binding. There was no clear change in erythrocyte invasion profile suggesting that the PY01185 gene product (designated PY235EBP-2) is able to fulfill the role of EBP-1 by serving as an invasion ligand although the molecular details of its interaction with erythrocytes have not been examined. The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family. In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another. We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression

    Body-related concerns and participation in physical education among adolescent students: the mediating role of motivation

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    BackgroundThere is a need to understand better factors influencing participation in physical education (PE) and the mechanisms involved. The adolescent years are characterised by increasing levels of body-related concerns. In PE, the body is judged for its physical abilities and subject to social comparisons and body judgements. Grounded in the Self-Determination Theory, this study aimed to explore whether body-related factors were associated with adolescents’ involvement in PE and whether types of motivation mediated this relationship.MethodsThe study involved 2,140 (54.5% girls) secondary students (15–16-year-olds) from Norway participating in the nationally representative “Health Behaviour in School-aged Children (HBSC) study: a WHO collaborative cross-national study.” Body-related factors included Body Mass Index (BMI), health complaints, body perception and dietary behaviours. Gender, age, and socioeconomic status (family affluence) were control variables. Motivation for PE was assessed with the Perceived Locus of Causality (PLOCQ) scale measuring three distinct factors: autonomous motivation, controlled motivation and amotivation. PE involvement was self-reported as weekly participation in PE classes and time spent in moderate-to-vigorous physical activity (MVPA) during PE.ResultsGender (girl), family affluence, health complaints, not being on a diet but wanting to lose weight, and body perception (too fat) were negatively associated with weekly PE participation when adjusting for other variables. This association was largely explained by students’ autonomous motivation in the case of health complaints and partly in the case of dietary behaviour and body perception. Similar results were observed for MVPA during PE lessons. Additionally, gender was associated with MVPA through amotivation.ConclusionThe study adds new knowledge to the understanding of the relationship between body-related factors and PE, supporting that autonomous motivation is a central mechanism and an avenue for further research. The results should be considered in planning high-quality PE classes and suggest that an autonomous supportive learning climate sensitive to body-related concerns should be a priority to increase adolescent involvement in PE

    Associations between family structure and adolescents’ food habits

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    Objective: To investigate family structure differences in adolescents’ consumption of fruit, vegetables, sweets and sugar-added soft drinks with adjustments for socio-demographic and socio-economic variables. Design: Cross-sectional data from the Health Behaviour in School-aged Children survey. Setting: Norwegian primary and secondary schools. Participants: Adolescents (n 4475) aged 11, 13, 15 and 16 years. Results: After adjusting for covariates, living in a single-mother family was associated with lower vegetable consumption (OR 0·76, 95 % CI 0·63, 0·91) and higher soft drink consumption (OR 1·29, 95 % CI 1·06, 1·57). Living in a mother and stepfather family was negatively associated with fruit (OR 0·71, 95 % CI 0·54, 0·95) and vegetable (OR 0·72, 95 % CI 0·54, 0·97) consumption. Living in a single-father family was associated with lower sweets consumption (OR 0·48, 95 % CI 0·32, 0·72). No significant interactions were demonstrated between family structure and socio-demographic or socio-economic covariates. Conclusions: The study suggests that an independent association between family structure and adolescents’ food habits exists.publishedVersio
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