357 research outputs found

    (Quantum) Space-Time as a Statistical Geometry of Fuzzy Lumps and the Connection with Random Metric Spaces

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    We develop a kind of pregeometry consisting of a web of overlapping fuzzy lumps which interact with each other. The individual lumps are understood as certain closely entangled subgraphs (cliques) in a dynamically evolving network which, in a certain approximation, can be visualized as a time-dependent random graph. This strand of ideas is merged with another one, deriving from ideas, developed some time ago by Menger et al, that is, the concept of probabilistic- or random metric spaces, representing a natural extension of the metrical continuum into a more microscopic regime. It is our general goal to find a better adapted geometric environment for the description of microphysics. In this sense one may it also view as a dynamical randomisation of the causal-set framework developed by e.g. Sorkin et al. In doing this we incorporate, as a perhaps new aspect, various concepts from fuzzy set theory.Comment: 25 pages, Latex, no figures, some references added, some minor changes added relating to previous wor

    Genetic improvement of Castor in the Western Hemisphere.

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    A mamona (Ricinus communis L.) tem o potencial de se tornar a principal cultura energética em grande parte do Hemisfério Ocidental. Essa colaboração internacional entre esses programas aumentará tanto a eficiência quanto a velocidade da pesquisa no desenvolvimento do mamona como matéria-prima para biocombustível. Castor (Ricinus communis L.) has the potential to become the primier energy crop across much of the Western Hemesphere. This international collaboration between these program will increase both the efficiency and speed of reaseach in developing Castor as a biofuel feedstock

    Donor to recipient age matching in lung transplantation: A European experience

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    \ua9 2024 The AuthorsBackground: The age profile of organ donors and patients on lung transplantation (LT) waiting lists have changed over time. In Europe, the donor population has aged much more rapidly than the recipient population, making allocation decisions on lungs from older donors common. In this study we assessed the impact of donor and recipient age discrepancy on LT outcomes in the UK and France. Methods: A retrospective analysis of all adult single or bilateral LT in France and the UK between 2010 and 2021. Recipients were stratified into 3 age author groups: young (≤30 years), middle-aged (30–60) and older (≥60). Their donors were also stratified into 2 groups <60, ≥60. Primary graft dysfunction (PGD) rates and recipient survival was compared between matched and mismatched donor and recipient age groups. Propensity matching was employed to minimize covariate imbalances and to improve the internal validity of our results. Results: Our study cohort was 4,696 lung transplant recipients (LTRs). In young and older LTRs, there was no significant difference in 1 and 5-year post-transplant survival dependent on the age category of the donor. Young LTRs who received older donor grafts had a higher risk of severe grade 3 PGD. Conclusion: Our findings show that clinically usable organs from older donors can be utilized safely in LT, even for younger recipients. Further research is needed to assess if the higher rate of PGD3 associated with use of older donors has an effect on long-term outcomes

    Genetics of Host Response to Leishmania tropica in Mice – Different Control of Skin Pathology, Chemokine Reaction, and Invasion into Spleen and Liver

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    Several hundred million people are exposed to the risk of leishmaniasis, a disease caused by intracellular protozoan parasites of several Leishmania species and transmitted by phlebotomine sand flies. In humans, L. tropica causes cutaneous form of leishmaniasis with painful and long-persisting lesions in the site of the insect bite, but the parasites can also penetrate to internal organs. The relationship between the host genes and development of the disease was demonstrated for numerous infectious diseases. However, the search for susceptibility genes in the human population could be a difficult task. In such cases, animal models may help to discover the role of different genes in interactions between the parasite and the host. Unfortunately, the literature contains only a few publications about the use of animals for L. tropica studies. Here, we report an animal model suitable for genetic, pathological and drug studies in L. tropica infection. We show how the host genotype influences different disease symptoms: skin lesions, parasite dissemination to the lymph nodes, spleen and liver, and increase of levels of chemokines CCL2, CCL3 and CCL5 in serum

    Genetic Control of Resistance to Trypanosoma brucei brucei Infection in Mice

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    Trypanosoma brucei are extracellular protozoa transmitted to mammalian host by the tsetse fly. They developed several mechanisms that subvert host's immune defenses. Therefore analysis of genes affecting host's resistance to infection can reveal critical aspects of host-parasite interactions. Trypanosoma brucei brucei infects many animal species including livestock, with particularly severe effects in horses and dogs. Mouse strains differ greatly in susceptibility to T. b. brucei. However, genes controlling susceptibility to this parasite have not been mapped. We analyzed the genetic control of survival after T. b. brucei infection using CcS/Dem recombinant congenic (RC) strains, each of which contains a different random set of 12.5% genes of their donor parental strain STS/A on the BALB/c genetic background. The RC strain CcS-11 is even more susceptible to parasites than BALB/c or STS/A. In F2 hybrids between BALB/c and CcS-11 we detected and mapped four loci, Tbbr1-4 (Trypanosoma brucei brucei response 1–4), that control survival after T. b. brucei infection. Tbbr1 (chromosome 3) and Tbbr2 (chromosome 12) have independent effects, Tbbr3 (chromosome 7) and Tbbr4 (chromosome 19) were detected by their mutual inter-genic interaction. Tbbr2 was precision mapped to a segment of 2.15 Mb that contains 26 genes

    A statistical model for the identification of genes governing the incidence of cancer with age

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    The cancer incidence increases with age. This epidemiological pattern of cancer incidence can be attributed to molecular and cellular processes of individual subjects. Also, the incidence of cancer with ages can be controlled by genes. Here we present a dynamic statistical model for explaining the epidemiological pattern of cancer incidence based on individual genes that regulate cancer formation and progression. We incorporate the mathematical equations of age-specific cancer incidence into a framework for functional mapping aimed at identifying quantitative trait loci (QTLs) for dynamic changes of a complex trait. The mathematical parameters that specify differences in the curve of cancer incidence among QTL genotypes are estimated within the context of maximum likelihood. The model provides testable quantitative hypotheses about the initiation and duration of genetic expression for QTLs involved in cancer progression. Computer simulation was used to examine the statistical behavior of the model. The model can be used as a tool for explaining the epidemiological pattern of cancer incidence
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