7 research outputs found

    Anomalous diffusion, nonlinear fractional Fokker-Planck equation and solutions

    Full text link
    We obtain new exact classes of solutions for the nonlinear fractional Fokker-Planck-like equation partial_t rho = partial_x{D(x) partial^{mu -1}_x rho^{nu} - F(x) rho} by considering a diffusion coefficient D = D|x|^{-theta} (theta in R and D>0) and a drift force F = -k_1 x + k-bar_{gamma} x|x|^{gamma-1} (k_1, k-bar_{gamma}, gamma in R). Connection with nonextensive statistical mechanics based on Tsallis entropy is also discussed.Comment: latex, 5 pages. Submitted to Physica

    Decoherence and CPT Violation in a Stringy Model of Space-Time Foam

    Full text link
    I discuss a model inspired from the string/brane framework, in which our Universe is represented as a three brane, propagating in a bulk space time punctured by D0-brane (D-particle) defects. As the D3-brane world moves in the bulk, the D-particles cross it, and from an effective observer on D3 the situation looks like a ``space-time foam'' with the defects ``flashing'' on and off (``D-particle foam''). The open strings, with their ends attached on the brane, which represent matter in this scenario, can interact with the D-particles on the D3-brane universe in a topologically non-trivial manner, involving splitting and capture of the strings by the D0-brane defects. Such processes are described by logarithmic conformal field theories on the world-sheet. Physically, they result in effective decoherence of the string matter on the D3 brane, and as a result, of CPT Violation, but of a type that implies an ill-defined nature of the effective CPT operator. Due to electric charge conservation, only electrically neutral (string) matter can exhibit such interactions with the D-particle foam. This may have unique, experimentally detectable, consequences for electrically-neutral entangled quantum matter states on the brane world, in particular the modification of the pertinent EPR Correlation of neutral mesons in a meson factory.Comment: 41 pages Latex, five eps figures incorporated. Uses special macro

    [Letter] Excessive placental secretion of neurokinin B during the third trimester causes pre-eclampsia

    No full text
    Pre-eclampsia is a principal cause of maternal morbidity and mortality, affecting 5-10% of first pregnancies worldwide. Manifestations include increased blood pressure, proteinuria, coagulopathy and peripheral and cerebral oedema. Although the aetiology and pathogenesis remain to be elucidated, the placenta is undoubtedly involved, as termination of pregnancy eradicates the disease. Here we have cloned a complementary DNA from human placental messenger RNA encoding a precursor protein of 121 amino acids which gives rise to a mature peptide identical to the neuropeptide neurokinin B (NKB) of other mammalian species. In female rats, concentrations of NKB several-fold above that of an animal 20 days into pregnancy caused substantial pressor activity. In human pregnancy, the expression of NKB was confined to the outer syncytiotrophoblast of the placenta, significant concentrations of NKB could be detected in plasma as early as week 9, and plasma concentrations of NKB were grossly elevated in pregnancy-induced hypertension and pre-eclampsia. We conclude that elevated levels of NKB in early pregnancy may be an indicator of hypertension and pre-eclampsia, and that treatment with certain neurokinin receptor antagonists may be useful in alleviating the symptoms

    Epidemiology of Lung Cancer

    No full text
    corecore