1,054 research outputs found

    Volume Weighted Measures of Eternal Inflation in the Bousso-Polchinski Landscape

    Get PDF
    We consider the cosmological dynamics associated with volume weighted measures of eternal inflation, in the Bousso-Polchinski model of the string theory landscape. We find that this measure predicts that observers are most likely to find themselves in low energy vacua with one flux considerably larger than the rest. Furthermore, it allows for a satisfactory anthropic explanation of the cosmological constant problem by producing a smooth, and approximately constant, distribution of potentially observable values of Lambda. The low energy vacua selected by this measure are often short lived. If we require anthropically acceptable vacua to have a minimum life-time of 10 billion years, then for reasonable parameters a typical observer should expect their vacuum to have a life-time of approximately 12 billion years. This prediction is model dependent, but may point toward a solution to the coincidence problem of cosmology.Comment: 35 pages, 8 figure

    Nucleotide Frequencies in Human Genome and Fibonacci Numbers

    Get PDF
    This work presents a mathematical model that establishes an interesting connection between nucleotide frequencies in human single-stranded DNA and the famous Fibonacci's numbers. The model relies on two assumptions. First, Chargaff's second parity rule should be valid, and, second, the nucleotide frequencies should approach limit values when the number of bases is sufficiently large. Under these two hypotheses, it is possible to predict the human nucleotide frequencies with accuracy. It is noteworthy, that the predicted values are solutions of an optimization problem, which is commonplace in many nature's phenomena.Comment: 12 pages, 2 figure

    The association between air pollution and the incidence of idiopathic pulmonary fibrosis in Northern Italy

    Get PDF
    Acute exacerbations and worsening of idiopathic pulmonary fibrosis (IPF) have been associated with exposure to ozone (O3), nitrogen dioxide (NO2) and particulate matter, but chronic exposure to air pollution might also affect the incidence of IPF. We investigated the association between chronic exposure to NO2, O3 and particulate matter with an aerodynamic diameter <10 \u3bcm (PM10) and IPF incidence in Northern Italy between 2005 and 2010. Daily predictions of PM10 concentrations were obtained from spatiotemporal models, and NO2 and O3 hourly concentrations from fixed monitoring stations. We identified areas with homogenous exposure to each pollutant. We built negative binomial models to assess the association between area-specific IPF incidence rate, estimated through administrative databases, and average overall and seasonal PM10, NO2, and 8-hour maximum O3 concentrations. Using unadjusted models, an increment of 10 \u3bcg\ub7m-3 in NO2 concentration was associated with an increase between 7.93% (95% CI 0.36-16.08%) and 8.41% (95% CI -0.23-17.80%) in IPF incidence rate, depending on the season. After adjustment for potential confounders, estimated effects were similar in magnitude, but with larger confidence intervals. Although confirmatory studies are needed, our results trace a potential association between exposure to traffic pollution and the development of IPF

    Charge conservation and time-varying speed of light

    Get PDF
    It has been recently claimed that cosmologies with time dependent speed of light might solve some of the problems of the standard cosmological scenario, as well as inflationary scenarios. In this letter we show that most of these models, when analyzed in a consistent way, lead to large violations of charge conservation. Thus, they are severly constrained by experiment, including those where cc is a power of the scale factor and those whose source term is the trace of the energy-momentum tensor. In addition, early Universe scenarios with a sudden change of cc related to baryogenesis are discarded.Comment: 4 page

    Do nonlinear waves in random media follow nonlinear diffusion equations?

    Full text link
    Probably yes, since we find a striking similarity in the spatio-temporal evolution of nonlinear diffusion equations and wave packet spreading in generic nonlinear disordered lattices, including self-similarity and scaling.Comment: 6 pages, 4 figure

    The Van der Waals interaction of the hydrogen molecule - an exact local energy density functional

    Full text link
    We verify that the van der Waals interaction and hence all dispersion interactions for the hydrogen molecule given by: W"= -{A/R^6}-{B/R^8}-{C/R^10}- ..., in which R is the internuclear separation, are exactly soluble. The constants A=6.4990267..., B=124.3990835 ... and C=1135.2140398... (in Hartree units) first obtained approximately by Pauling and Beach (PB) [1] using a linear variational method, can be shown to be obtainable to any desired accuracy via our exact solution. In addition we shall show that a local energy density functional can be obtained, whose variational solution rederives the exact solution for this problem. This demonstrates explicitly that a static local density functional theory exists for this system. We conclude with remarks about generalising the method to other hydrogenic systems and also to helium.Comment: 11 pages, 13 figures and 28 reference

    An Infrared Divergence Problem in the cosmological measure theory and the anthropic reasoning

    Full text link
    An anthropic principle has made it possible to answer the difficult question of why the observable value of cosmological constant (Λ1047\Lambda\sim 10^{-47} GeV4{}^4) is so disconcertingly tiny compared to predicted value of vacuum energy density ρSUSY1012\rho_{SUSY}\sim 10^{12} GeV4{}^4. Unfortunately, there is a darker side to this argument, as it consequently leads to another absurd prediction: that the probability to observe the value Λ=0\Lambda=0 for randomly selected observer exactly equals to 1. We'll call this controversy an infrared divergence problem. It is shown that the IRD prediction can be avoided with the help of a Linde-Vanchurin {\em singular runaway measure} coupled with the calculation of relative Bayesian probabilities by the means of the {\em doomsday argument}. Moreover, it is shown that while the IRD problem occurs for the {\em prediction stage} of value of Λ\Lambda, it disappears at the {\em explanatory stage} when Λ\Lambda has already been measured by the observer.Comment: 9 pages, RevTe

    Psychoanalysis as the Patient: High in Feeling, Low in Energy

    Full text link
    This paper examines the increasingly important role that affect is assuming in psychoanalytic research and practice. This rise in the centrality of affect has been at the expense of an independent role for motivation and a dismissal of any energy concept. Difficulties with this affect-first approach are identified and an alternative offered that accords motivation an independent role and accommodates a useful energy concept. Research on esophageal atresia, addiction, and infant suckling are cited in support of this position.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66624/2/10.1177_00030651970450031101.pd

    Associations between long-term fine particulate matter exposure and hospital procedures in heart failure patients

    Get PDF
    Background Ambient fine particulate matter (PM2.5) contributes to global morbidity and mortality. One way to understand the health effects of PM2.5 is by examining its impact on performed hospital procedures, particularly among those with existing chronic disease. However, such studies are rare. Here, we investigated the associations between annual average PM2.5 and hospital procedures among individuals with heart failure. Methods Using electronic health records from the University of North Carolina Healthcare System, we created a retrospective cohort of 15,979 heart failure patients who had at least one of 53 common (frequency > 10%) procedures. We used daily modeled PM2.5 at 1x1 km resolution to estimate the annual average PM2.5 at the time of heart failure diagnosis. We used quasi- Poisson models to estimate associations between PM2.5 and the number of performed hospital procedures over the follow-up period (12/31/2016 or date of death) while adjusting for age at heart failure diagnosis, race, sex, year of visit, and socioeconomic status. Results A 1 μg/m3 increase in annual average PM2.5 was associated with increased glycosylated hemoglobin tests (10.8%; 95% confidence interval = 6.56%, 15.1%), prothrombin time tests (15.8%; 95% confidence interval = 9.07%, 22.9%), and stress tests (6.84%; 95% confidence interval = 3.65%, 10.1%). Results were stable under multiple sensitivity analyses. Conclusions These results suggest that long-term PM2.5 exposure is associated with an increased need for diagnostic testing on heart failure patients. Overall, these associations give a unique lens into patient morbidity and potential drivers of healthcare costs linked to PM2.5 exposure
    corecore