Heterogeneity of Cancer Risk Due to Stochastic Effects

Persons with exactly the same genetic background, behavior, environment, etc. may have differences in cancer risk due to a different number of cells on the way to malignancy. These differences are estimated quantitatively by using the two-stage clonal expansion model. For liver cancer the estimated relative risk for persons without intermediate cells at age 40 is less than 10% when compared to the risk of the total population, while the top 0.1% risk group has a more than 100-fold risk compared to the population. The risk of the 1% percentile in risk is more than 100-fold of the risk of the more than 95% persons without intermediate cells. The number of intermediate (premalignant) cells in the risk groups cannot be calculated from incidence data only because they depend strongly on a nonidentifiable parameter. But under plausible assumptions, less than about 1,000 intermediate cells are present at age 40 even in high-risk persons.     

The uncertain timing of reaching 8 billion, peak world population, and other demographic milestones

We present new probabilistic forecasts of the timing of the world's population reaching 8 billion, the world's peak population, and the date at which one-third or more of the world's population would be 60+ years old. The timing of these milestones, as well as the timing of the Day of 7 Billion, is uncertain. We compute that the 60 percent prediction interval for the Day of 8 Billion is between 2024 and 2033. Our figures show that there is around a 60 percent chance that one-third of the world's population would be 60+ years old in 2100. In the UN 2010 medium variant, that proportion never reaches one-third. As in our past forecasts (Lutz et al. 2001, 2008), we find the chance that the world's population will peak in this century to be around 84 percent and the timing of that peak to be highly uncertain. Focal days, like the Day of 7 Billion, play a role in raising public awareness of population issues, but they give a false sense of the certainty of our knowledge. The uncertainty of the timing of demographic milestones is not a constant of nature. Understanding the true extent of our demographic uncertainty can help motivate governments and other agencies to make the investments necessary to reduce it.     

黑夜意识和女性的(自我)毁灭--评现代中国的黑暗理论

文章对黑暗/夜的概念在中国语境中的演绎进行了调查:首先对黑暗(darkness)和黑夜(night)在中国传统文化中的使用加以评说,然后讨论其在现当代中国文学中的使用,最后着重讨论女作家翟永明(1955-)和她将女性精神理解为“黑夜意识”(nocturnalconsciousness)的观点。文章认为人们只有从夜里才能看到黑暗,从黑暗中才能见到光明。     

Testing a Regression Model When We Have Smooth Alternatives in Mind

Goodness-of-fit tests based on residual sums of squares are standard procedures used when fitting regression models. Often we have a smooth alternative in mind, a qualitative feature that the χ²-test does not take into account. We show that the power of detecting a smooth alternative increases when we smooth the current model as well. The proposed test is shown to be able to detect any continuous local alternative tending to zero slower than n ^−1/2. Theoretical results also address minimax non-parametric hypothesis testing in Sobolev spaces. A simulation study is presented, and the procedure is applied to expenditure curve estimation.     

Correction to: Comparison of joint control schemes for multivariate normal i.i.d. output

AStA Advances in Statistical Analysis - In the original paper, we incorrectly stated that...     

CUSUM control schemes for monitoring the covariance matrix of multivariate time series

Modified cumulative sum (CUSUM) control charts and CUSUM schemes for residuals are suggested to detect changes in the covariance matrix of multivariate time series. Several properties of these schemes are derived when the in-control process is a stationary Gaussian process. A Monte Carlo study reveals that the proposed approaches show similar or even better performance than the schemes based on the multivariate exponentially weighted moving average (MEWMA) recursion. We illustrate how the control procedures can be applied to monitor the covariance structure of developed stock market indices.