Learner centered design programs typically focus on analyzing the needs of students or encouraging more students to participate in classroom activities.This paper argues that the real learner centered approach should ...Learner centered design programs typically focus on analyzing the needs of students or encouraging more students to participate in classroom activities.This paper argues that the real learner centered approach should consider allowing learners to play a greater role in learning management,learning methods and learning opportunities by providing selection for the learners.This opportunity can be introduced into the traditional classroom with minimize the problems.The learner's choice as a more basic aspect of language curriculum can be provided by establish autonomous learning center.Teachers'and learners'attitudes to the centre are discussed,and it is suggested that we should do more things to guide both teachers'and learners'expectations in order to make learner choices an active feature of foreign language study.展开更多
Background: Generally, clinicians do not accurately estimate life expec-tancy in terminally ill patients with cancer. Aim: To evaluate the value of the Prognostic Nutritional Index (PNI) for accurately estimating the ...Background: Generally, clinicians do not accurately estimate life expec-tancy in terminally ill patients with cancer. Aim: To evaluate the value of the Prognostic Nutritional Index (PNI) for accurately estimating the life expectancy of patients with end-stage oral cancer. Design: A longitudinal section study. Setting/participants: Fifteen patients (12 men;mean age: 71.7 years) who died of oral cancer between 2005 and 2014 (the terminal group) were included. The mean PNI values at the initial visit and at 3, 2, and 1 months before the deaths were comparatively analyzed. Results: The mean follow-up period was 133 days. At the initial examination, the PNI values were 49.1 ± 4.5 (p = 0.6723). The PNI value of the terminal group was 35.6 ± 5.1 at 2 months before death and 28.6 ± 3.0 at 1 month before death. The PNI values at 3, 2, and 1 months before death in the terminal group significantly differed from each other and from that at the initial visit and steadily decreased until death. Conclusions: Our findings suggest the utility of PNI as a prognostic index in patients with end-stage oral cancer patients. Furthermore, the PNI should be routinely considered in the nutritional management of patients with oral cancer nearing death.展开更多
Sample size re-estimation is essential in oncology studies. However, the use of blinded sample size reassessment for survival data has been rarely reported. Based on the density function of the exponential distributio...Sample size re-estimation is essential in oncology studies. However, the use of blinded sample size reassessment for survival data has been rarely reported. Based on the density function of the exponential distribution, an expectation-maximization（EM） algorithm of the hazard ratio was derived, and several simulation studies were used to verify its applications. The method had obvious variation in the hazard ratio estimates and overestimation for the relatively small hazard ratios. Our studies showed that the stability of the EM estimation results directly correlated with the sample size, the convergence of the EM algorithm was impacted by the initial values, and a balanced design produced the best estimates. No reliable blinded sample size re-estimation inference can be made in our studies, but the results provide useful information to steer the practitioners in this field from repeating the same endeavor.展开更多
Someone or the other is always pointing to a published study to justify a point of view or the need for a change in what we do or how we live. There are so many such studies, many reported in top-notch journals, repor...Someone or the other is always pointing to a published study to justify a point of view or the need for a change in what we do or how we live. There are so many such studies, many reported in top-notch journals, reporting results inconsistent across and often inconsistent within. It is in the interest of increasing the credibility of science, and to safeguard the general public living with its overt and covert influence, to filter good science from bad. Some inferences are good, even when counter-intuitive or seemingly inconsistent, and are likely to withstand scrutiny and some others may represent marginal effects in the aggregate not entirely useful for individual choices or decisions, and are often non-reproducible. The New York Times featured an article in August 2018 debunking some of the reported studies supporting testing for Vitamin D deficiencies and the recommendation of large supplemental doses of Vitamin D. Some of these Vitamin D claims, among other claims, were reported as not holding up on replication in controlled trials [1]. We have noted in Ref. [2] that we need to be wary as individuals about reported signals detected in studies using stochastic data, even when these aggregate signals are of a large magnitude. We demonstrated discordance rates of 30% or higher between subject level assessments of effect and the conclusion drawn in the aggregate. Here we will provide a computation of this discordant proportion as well as post-hoc assessments of aggregate inferences, with emphasis on evaluating studies with time-to-event endpoints such as those in cancer trials. Similar evaluations for continuous, binomial data and correlations are also provided. We also discuss the use of response thresholds.展开更多
文摘Learner centered design programs typically focus on analyzing the needs of students or encouraging more students to participate in classroom activities.This paper argues that the real learner centered approach should consider allowing learners to play a greater role in learning management,learning methods and learning opportunities by providing selection for the learners.This opportunity can be introduced into the traditional classroom with minimize the problems.The learner's choice as a more basic aspect of language curriculum can be provided by establish autonomous learning center.Teachers'and learners'attitudes to the centre are discussed,and it is suggested that we should do more things to guide both teachers'and learners'expectations in order to make learner choices an active feature of foreign language study.
文摘Background: Generally, clinicians do not accurately estimate life expec-tancy in terminally ill patients with cancer. Aim: To evaluate the value of the Prognostic Nutritional Index (PNI) for accurately estimating the life expectancy of patients with end-stage oral cancer. Design: A longitudinal section study. Setting/participants: Fifteen patients (12 men;mean age: 71.7 years) who died of oral cancer between 2005 and 2014 (the terminal group) were included. The mean PNI values at the initial visit and at 3, 2, and 1 months before the deaths were comparatively analyzed. Results: The mean follow-up period was 133 days. At the initial examination, the PNI values were 49.1 ± 4.5 (p = 0.6723). The PNI value of the terminal group was 35.6 ± 5.1 at 2 months before death and 28.6 ± 3.0 at 1 month before death. The PNI values at 3, 2, and 1 months before death in the terminal group significantly differed from each other and from that at the initial visit and steadily decreased until death. Conclusions: Our findings suggest the utility of PNI as a prognostic index in patients with end-stage oral cancer patients. Furthermore, the PNI should be routinely considered in the nutritional management of patients with oral cancer nearing death.
基金supported by the National Natural Science Foundation of China(81273184)the National Natural Science Foundation of China Grant for Young Scientists (81302512)
文摘Sample size re-estimation is essential in oncology studies. However, the use of blinded sample size reassessment for survival data has been rarely reported. Based on the density function of the exponential distribution, an expectation-maximization（EM） algorithm of the hazard ratio was derived, and several simulation studies were used to verify its applications. The method had obvious variation in the hazard ratio estimates and overestimation for the relatively small hazard ratios. Our studies showed that the stability of the EM estimation results directly correlated with the sample size, the convergence of the EM algorithm was impacted by the initial values, and a balanced design produced the best estimates. No reliable blinded sample size re-estimation inference can be made in our studies, but the results provide useful information to steer the practitioners in this field from repeating the same endeavor.
文摘Someone or the other is always pointing to a published study to justify a point of view or the need for a change in what we do or how we live. There are so many such studies, many reported in top-notch journals, reporting results inconsistent across and often inconsistent within. It is in the interest of increasing the credibility of science, and to safeguard the general public living with its overt and covert influence, to filter good science from bad. Some inferences are good, even when counter-intuitive or seemingly inconsistent, and are likely to withstand scrutiny and some others may represent marginal effects in the aggregate not entirely useful for individual choices or decisions, and are often non-reproducible. The New York Times featured an article in August 2018 debunking some of the reported studies supporting testing for Vitamin D deficiencies and the recommendation of large supplemental doses of Vitamin D. Some of these Vitamin D claims, among other claims, were reported as not holding up on replication in controlled trials [1]. We have noted in Ref. [2] that we need to be wary as individuals about reported signals detected in studies using stochastic data, even when these aggregate signals are of a large magnitude. We demonstrated discordance rates of 30% or higher between subject level assessments of effect and the conclusion drawn in the aggregate. Here we will provide a computation of this discordant proportion as well as post-hoc assessments of aggregate inferences, with emphasis on evaluating studies with time-to-event endpoints such as those in cancer trials. Similar evaluations for continuous, binomial data and correlations are also provided. We also discuss the use of response thresholds.
