On the Covariate-adjusted Estimation for an Overall Treatment Difference with Data from a Randomized Comparative Clinical Trial

To estimate an overall treatment difference with data from a randomized comparative clinical study, baseline covariates are often utilized to increase the estimation precision. Using the standard analysis of covariance technique for making inferences about such an average treatment difference may not be appropriate, especially when the fitted model is nonlinear. On the other hand, the novel augmentation procedure recently studied, for example, by Zhang and others (2008. Improving efficiency of inferences in randomized clinical trials using auxiliary covariates. Biometrics 64, 707–715) is quite flexible. However, in general, it is not clear how to select covariates for augmentation effectively. An overly adjusted estimator may inflate the variance and in some cases be biased. Furthermore, the results from the standard inference procedure by ignoring the sampling variation from the variable selection process may not be valid. In this paper, we first propose an estimation procedure, which augments the simple treatment contrast estimator directly with covariates. The new proposal is asymptotically equivalent to the aforementioned augmentation method. To select covariates, we utilize the standard lasso procedure. Furthermore, to make valid inference from the resulting lasso-type estimator, a cross validation method is used. The validity of the new proposal is justified theoretically and empirically. We illustrate the procedure extensively with a well-known primary biliary cirrhosis clinical trial data set

Effectively Selecting a Target Population for a Future Comparative Study

When comparing a new treatment with a control in a randomized clinical study, the treatment effect is generally assessed by evaluating a summary measure over a specific study population. The success of the trial heavily depends on the choice of such a population. In this paper, we show a systematic, effective way to identify a promising population, for which the new treatment is expected to have a desired benefit, using the data from a current study involving similar comparator treatments. Specifically, with the existing data we first create a parametric scoring system using multiple covariates to estimate subject-specific treatment differences. Using this system, we specify a desired level of treatment difference and create a subgroup of patients, defined as those whose estimated scores exceed this threshold. An empirically calibrated group-specific treatment difference curve across a range of threshold values is constructed. The population of patients with any desired level of treatment benefit can then be identified accordingly. To avoid any ``self-serving\u27\u27 bias, we utilize a cross-training-evaluation method for implementing the above two-step procedure. Lastly, we show how to select the best scoring system among all competing models. The proposals are illustrated with the data from two clinical trials in treating AIDS and cardiovascular diseases. Note that if we are not interested in designing a new study for comparing similar treatments, the new procedure can also be quite useful for the management of future patients who would receive nontrivial benefits to compensate for the risk or cost of the new treatment

Ad Hoc Quantum Network Routing Protocol based on Quantum Teleportation

Abstract-In this paper, a quantum communication routing protocol is designed for quantum ad hoc network. This protocol is on-demand routing based on EPR numbers shared by adjacent nodes, concerning that it is a limited source. When quantum channel is established, quantum states from one quantum device can be teleport to another even when they do not share EPR pairs wirelessly. Part of information transferred by classic channel can be dealt with using simple logics. In this way, the goal of safety communication between source and destination is realized, improving the weakness of ad hoc network such as Eavesdropping and Active attacks. In terms of time complexity, the mechanism transports a quantum bit in time almost the same as the quantum teleportation does regardless of the number of hops between the source and destination. Index Terms-EPR pair, quantum route, quantum entanglement, ad hoc network, quantum teleportation

Assessment of the feasibility and coverage of a modified universal hearing screening protocol for use with newborn babies of migrant workers in Beijing

BACKGROUND: Although migrant workers account for the majority of newborns in Beijing, their children are less likely to undergo appropriate universal newborn hearing screening/rescreening (UNHS) than newborns of local non-migrant residents. We hypothesised that this was at least in part due to the inadequacy of the UNHS protocol currently employed for newborn babies, and therefore aimed to modify the protocol to specifically reflect the needs of the migrant population. METHODS: A total of 10,983 healthy babies born to migrant mothers between January 2007 and December 2009 at a Beijing public hospital were investigated for hearing abnormalities according to a modified UNHS protocol. This incorporated two additional/optional otoacoustic emissions (OAE) tests at 24–48 hours and 2 months after birth. Infants not passing a screening test were referred to the next test, until any hearing loss was confirmed by the auditory brainstem response (ABR) test. RESULTS: A total of 98.91% (10983/11104) of all newborn children underwent the initial OAE test, of which 27.22% (2990/10983) failed the test. 1712 of the failed babies underwent the second inpatient OAE test, with739 failing again; thus significantly decreasing the overall positive rate for abnormal hearing from 27.22% to 18.36% ([2990–973 /10983)]; p = 0). Overall, 1147(56.87%) babies underwent the outpatient OAE test again after1-month, of whom 228 failed and were referred for the second outpatient OAE test (i.e. 2.08% (228/10983) referral rate at 1month of age). 141 of these infants underwent the referral test, of whom 103 (73.05%) tested positive again and were referred for a final ABR test for hearing loss (i.e. final referral rate of 1.73% ([228-38/10983] at 2 months of age). Only 54 infants attended the ABR test and 35 (0.32% of the original cohort tested) were diagnosed with abnormal hearing. CONCLUSIONS: Our study shows that it is feasible and practical to achieve high coverage rates for screening hearing loss and decrease the referral rates in newborn babies of migrant workers, using a modification of the currently employed UNHS protocol

Evaluations of virtual and augmented reality technology-enhanced learning for higher education

Virtual reality (VR) has good potential to promote technology-enhanced learning. Students can benefit from immersive visualization and intuitive interaction in their learning of abstract concepts, complex structures, and dynamic processes. This paper is interested in evaluating the effects of VR learning games in a Virtual and Augmented Reality Technology-Enhanced Learning (VARTeL) environment within an engineering education setting. A VARTeL flipped classroom is established in the HIVE learning hub at Nanyang Technological University (NTU) Singapore for the immersive and interactive learning. Experiments are designed for the university students conducting the learning, with three interactive and immersive VR games related to science, technology, engineering and mathematics (STEM), i.e., virtual cells, a virtual F1 racing car, and vector geometry. These VR games are a part of the VARTeL apps designed in-house at NTU for STEM education. Quantitative and qualitative analyses are performed. A total of 156 students from Mechanical Engineering participated in the experiment. There are 15 participants selected for an interview after the experiment. Pre-tests and post-tests are performed using two different models, the developed VARTeL and the modified Technology-Rich Outcome-Focused Learning Environment Inventory (TROFLEI), in order to measure the efficiency of the VARTeL environment in Higher Education. Significant improvements of about 24.8% are observed for the post-tests over the pre-tests, which illustrate the effectiveness of the VARTeL for Engineering education. Details of the VR simulation games, methods of data collection, data analyses, as well as the experiment results are discussed. It is observed from the results that all the underlying scales of the modified TROFLEI are above the threshold for the ‘Good’ category, indicating that a very reliable questionnaire is designed in this research. The mean ‘Ideal’ values are about 0.7–2.6% higher than the mean ‘Actual’ values. The limitations of the experiment and future works with recommendations are also presented in this paper