24,107 research outputs found
Global Epidemiology of Lung Cancer.
While lung cancer has been the leading cause of cancer-related deaths for many years in the United States, incidence and mortality statistics - among other measures - vary widely worldwide. The aim of this study was to review the evidence on lung cancer epidemiology, including data of international scope with comparisons of economically, socially, and biologically different patient groups. In industrialized nations, evolving social and cultural smoking patterns have led to rising or plateauing rates of lung cancer in women, lagging the long-declining smoking and cancer incidence rates in men. In contrast, emerging economies vary widely in smoking practices and cancer incidence but commonly also harbor risks from environmental exposures, particularly widespread air pollution. Recent research has also revealed clinical, radiologic, and pathologic correlates, leading to greater knowledge in molecular profiling and targeted therapeutics, as well as an emphasis on the rising incidence of adenocarcinoma histology. Furthermore, emergent evidence about the benefits of lung cancer screening has led to efforts to identify high-risk smokers and development of prediction tools. This review also includes a discussion on the epidemiologic characteristics of special groups including women and nonsmokers. Varying trends in smoking largely dictate international patterns in lung cancer incidence and mortality. With declining smoking rates in developed countries and knowledge gains made through molecular profiling of tumors, the emergence of new risk factors and disease features will lead to changes in the landscape of lung cancer epidemiology
Fluctuating observation time ensembles in the thermodynamics of trajectories
The dynamics of stochastic systems, both classical and quantum, can be
studied by analysing the statistical properties of dynamical trajectories. The
properties of ensembles of such trajectories for long, but fixed, times are
described by large-deviation (LD) rate functions. These LD functions play the
role of dynamical free-energies: they are cumulant generating functions for
time-integrated observables, and their analytic structure encodes dynamical
phase behaviour. This "thermodynamics of trajectories" approach is to
trajectories and dynamics what the equilibrium ensemble method of statistical
mechanics is to configurations and statics. Here we show that, just like in the
static case, there is a variety of alternative ensembles of trajectories, each
defined by their global constraints, with that of trajectories of fixed total
time being just one of these. We show that an ensemble of trajectories where
some time-extensive quantity is constant (and large) but where total
observation time fluctuates, is equivalent to the fixed-time ensemble, and the
LD functions that describe one ensemble can be obtained from those that
describe the other. We discuss how the equivalence between generalised
ensembles can be exploited in path sampling schemes for generating rare
dynamical trajectories.Comment: 12 pages, 5 figure
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