16 Matching Annotations
  1. Aug 2019
    1. so that instead of predicting the time of event, we are predicting the probability that an event happens at a particular time .
  2. Jul 2019
    1. In practice, we found that it is not appropriate to use Aalen’s additive hazardsmodel for all datasets, because when we estimate cumulativeregression functionsB(t),they are restricted to the time interval where X (X has been defined in Chapter 3) is offull rank, that meansX0Xis invertible. Sometimes we found that X is not of full rank,which was not a problem with the Cox model.
    2. An overall conclusion is that the two models give different pieces of informationand should not be viewed as alternatives to each other, but ascomplementary methodsthat may be used together to give a fuller and more comprehensive understanding ofdata
    3. The effect ofthe covariates on survival is to act multiplicatively on some unknown baseline hazardrate, which makes it difficult to model covariate effects that change over time. Secondly,if covariates are deleted from a model or measured with a different level of precision, theproportional hazards assumption is no longer valid. These weaknesses in the Cox modelhave generated interest in alternative models. One such alternative model is Aalen’s(1989) additive model. This model assumes that covariates act in an additive manneron an unknown baseline hazard rate. The unknown risk coefficients are allowed to befunctions of time, so that the effect of a covariate may vary over time.
    1. Note that, three often used transformations can be specified using the argument fun: “log”: log transformation of the survivor function, “event”: plots cumulative events (f(y) = 1-y). It’s also known as the cumulative incidence, “cumhaz” plots the cumulative hazard function (f(y) = -log(y))
    2. Note that, the confidence limits are wide at the tail of the curves, making meaningful interpretations difficult. This can be explained by the fact that, in practice, there are usually patients who are lost to follow-up or alive at the end of follow-up. Thus, it may be sensible to shorten plots before the end of follow-up on the x-axis (Pocock et al, 2002).
    1. RF is now a standard to effectively analyze a large number of variables, of many different types, with no previous variable selection process. It is not parametric, and in particular for survival target it does not assume the proportional risks assumption.
    1. Thesurvival function gives,for every time,the probability of surviving(or not experiencing the event) up to that time.The hazard function gives the potential that the event will occur, per time unit, given that an individual has survived up to the specified time.
  3. Oct 2016
    1. dried tubers.

      Merely surviving on the little bits of life that still exist during the winter. Feeding on mainly potatoes and whatever else can be found.

  4. Jul 2016
    1. what is the English-speaking world missing out on by not reading the content written in other languages

      Though he’s been associated with a very strange idea he never had, Edward Sapir was quite explicit about this loss over a hundred years ago. Thinking specifically about a later passage warning people about the glossocide English language. But it’s been clear in his work from long before that excerpt that we’re missing out when we focus on a single language.

  5. Oct 2015
    1. Over time, they have created massive communi-ties with millions of inhabitants, complex lifeworlds, economic arrange-ments, cultural practices and life-styles

      The people will find a way to survive.. they always do.. but we should be able to find easier ways to make that happen that will provide better situations for them.

    2. Here in the city-escapes, under bridges, ingraveyards and side streets, street children have formed “flourishing”outdoor communities, some with elaborate order, discipline, and an
    3. heyhave spread among educated young people with higher status, aspirationsand social skills—government employees, teachers, and professionals

      Changes in the environment are reflected by the characteristics of society.

  6. Feb 2015
  7. Oct 2013
    1. anyone is under the impression that people who rob others or falsify accounts or do any evil thing get the advantage, he is wrong in his thinking; for none are at a greater disadvantage throughout their lives than such men; none are found in more difficult straits, none live in greater ignominy; and, in a word, none are more miserable than they.

      This is a really good point. They are all at a very low point doing what they have to do (even though it is wrong) to survive.

  8. Sep 2013
    1. preservation of the species

      consider in context of Darwinian "survival", and interesting to consider the contrast with Berlant's "Slow Death" concept--hunger to the point of obesity, love striving after objects to the point of depression