Comparative Evaluation of Balancing Properties of Stratified Randomization Procedures

2009 ◽  
Vol 48 (02) ◽  
pp. 129-134 ◽  
Author(s):  
G. Kundt
Keyword(s):  
Clinical Trial ◽  
Prognostic Factors ◽  
Block Size ◽  
Multicenter Trial ◽  
Superior Performance ◽  
Good Tool ◽  
Minimization Method ◽  
Block Randomization ◽  
The Difference ◽  
The Impact

Summary Objectives: If in a clinical trial prognostic factors are known in advance to be associated with the outcome of a patient it is often recommended that the randomization for a clinical trial should be stratified on these factors, particularly in a multicenter trial. Unfortunately, stratified or covariate-adaptive randomization does not always promote greater balance between the numbers of treatment assignments to A and B within each stratum and thus overall. Because such designs have numerous parameters that must be specified, simulation is a good tool to investigate the impact of these parameters on balance. Methods: We investigate and discuss in more detail the difference in balancing performance of three stratified randomization procedures. The permuted-block randomization within strata, the “minimization” method and “self-adjusting” design are assessed overall, within levels of prognostic factors, and within strata. Results: We show the superior performance of “self-adjusting” design and the extent of balancing losses occurring with permuted-block randomization within levels of factors and with “minimization” within strata. A summary of principal conclusions regarding the balancing properties of stratified randomization procedures is presented and general recommendations are offered. Conclusions: The relative merits of each procedure should be weighted carefully in relation to the characteristics of the trial. Considering the likelihood of imbalances, the sample size and values of parameters of stratified randomization procedures (number of prognostic factors, number of factor levels, block size) are important when choosing a randomization procedure.

L1–2 minimization for P- and S-impedance inversion

2020 ◽  
Vol 8 (2) ◽  
pp. T379-T390
Author(s):  
Wenliang Nie ◽  
Xiaotao Wen ◽  
Jixin Yang ◽  
Jian He ◽  
Kai Lin ◽  
...  
Keyword(s):  
Objective Function ◽  
Reservoir Characterization ◽  
A Priori ◽  
Low Frequency ◽  
Superior Performance ◽  
Minimization Method ◽  
Block Boundary ◽  
Avo Inversion ◽  
Impedance Inversion ◽  
The Difference

Amplitude variation with offset (AVO) inversion has been widely used in reservoir characterization to predict lithology and fluids. However, some existing AVO inversion methods that use [Formula: see text] norm regularization may not obtain the block boundary of subsurface layers because the AVO inversion is a severely ill-posed problem. To obtain sparse and accurate solutions, we have introduced the [Formula: see text] minimization method as an alternative to [Formula: see text] norm regularization. We used [Formula: see text] minimization for simultaneous P- and S-impedance inversion from prestack seismic data. We first derived the forward problem with multiangles and set up the inversion objective function with constraints of a priori low-frequency information obtained from well-log data. Then, we introduced minimization of the difference of [Formula: see text] and [Formula: see text] norms, denoted as [Formula: see text] minimization, to solve this objective function. The nonconvex penalty function of the [Formula: see text] minimization method is decomposed into two convex subproblems via the difference of convex algorithm, and each subproblem is solved by the alternating direction method of multipliers. Compared to [Formula: see text] norm regularization, the results indicate that [Formula: see text] minimization has superior performance over [Formula: see text] norm regularization in promoting blocky/sparse solutions. Tests on synthetic and field data indicate that our method can provide sparser and more accurate P- and S-impedance inversion results. The overall results confirm that our method has great potential in the detection and identification of fluids.

scholarly journals A Single-Center Retrospective Study of the Impact of Thyroid Cancer on the Malignant Risk of Contralateral TI-RADS 3 and 4 Nodules

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Huan Liu ◽  
Jun Jin ◽  
Qiao Chen ◽  
Zhongmin Li
Keyword(s):  
Clinical Trial ◽  
Thyroid Cancer ◽  
Multivariate Logistic Regression Analysis ◽  
Control Group ◽  
Confounding Factors ◽  
Clinical Trial Registry ◽  
Clinical Trial Registration ◽  
The Difference ◽  
The Impact ◽  
Experimental Group

Background. The incidence of thyroid nodules increases in the general population. Similarly, we have also seen a dramatic increase in the number of thyroid surgeries. However, the mortality rate of thyroid cancer remained stable or even decreased. The purpose of our study was to investigate whether thyroid cancer affects the malignant risk of the contralateral TI-RADS 3 and 4 nodules. Methods. We conducted a retrospective cohort study in our institution for all thyroid procedures due to nodules from December 2018 to December 2019. All eligible patients were divided into the experimental group (bilateral nodules) and the control group (unilateral nodules) to assess whether the proportion of malignant nodules was different between the two groups. Multivariate logistic regression analysis was used to control potential confounding factors to investigate whether their differences were statistically significant. Results. A total of 330 patients underwent thyroid surgery, of whom 137 were eligible, including 84 in the experimental group and 53 in the control group. The proportion of malignant nodules was significantly different between the experimental group and the control group (29.8% versus 58.5%, unadjusted OR 0.30, 95% CI: 0.17–0.82, p = 0.001 ). However, after controlling for potential confounding factors, including age ( p = 0.004 ), gender ( p = 0.775 ), and TI-RADS classification ( p ≤ 0.001 ), we found that the difference was not significant (adjusted OR 1.08, 95% CI: 0.39–3.01, p = 0.886 ). Conclusion. There is no evidence that thyroid cancer affects the malignant risk of the contralateral TI-RADS 3 and 4 nodules. This study has been registered with the Chinese Clinical Trial Registry (clinical trial registration number: ChiCTR2000038611, registration time: September 26, 2020).

scholarly journals Impact of a Collaborative Clinical Trials Methodology Course on Trainees’ Funding and Clinical Trials Activity

2021 ◽  
Author(s):  
Shirley Yang ◽  
William Meurer
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Course Completion ◽  
Project Study ◽  
Start Date ◽  
Online Databases ◽  
The Difference ◽  
Nih Funding ◽  
The Impact ◽  
Trials Methodology

Introduction Clinical trials are challenging, and many junior investigators lack the skills to move through the phases in a coherent way. To address this issue in the clinical neurosciences, the NINDS Clinical Trials Methodology Course (CTMC) was created through cross university collaborations to provide junior investigators with relevant education and training to promote well-designed clinical trials. This study aims to explore the impact of CTMC by determining the trajectory of NIH funding and clinical trials activity in trainees after completion of the course. Methods The online databases NIH RePORTER and ClinicalTrials.gov were searched respectively to determine NIH funding and clinical trials activity of each CTMC trainee between 2014-2017. Data was collected on the Project Start Date of the first NIH grant and the Study Start Date of the first non-withdrawn clinical trial each trainee had after taking CTMC. Grants or trials prior to CTMC were noted. The date of a trainee’s CTMC was designated as January 1 st of the year following course completion. Time until grant or clinical trial was calculated as the difference between the Project/Study Start Date and the trainee’s CTMC date. Results and Discussion There were 131 CTMC trainees between 2014-2017. As of early 2019, 23.7% of these trainees received a NIH grant and 43.5% became involved in a clinical trial after the course. Excluding those with prior experience, 11.5% of all trainees received their first-ever NIH grant and 27.5% became involved in their first-ever clinical trial following completion of CTMC. For all trainees who received a NIH grant or became involved in a clinical trial after the course, the median times to these achievements were 1.1 years (IQR 0.5-1.9 years) and 1.2 years (IQR 0.6-2.2 years), respectively. These results suggest that completing CTMC may help promote successful funding and clinical trials by junior investigators.

Impact of 68Ga-PSMA-11 PET on the management of biochemically recurrent prostate cancer in a prospective single-arm clinical trial.

2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 292-292
Author(s):  
Wolfgang Fendler ◽  
Justin Ferdinandus ◽  
Jeremie Calais ◽  
Matthias Eiber ◽  
Robert R. Flavell ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Clinical Trial ◽  
Diagnostic Tests ◽  
Biochemical Recurrence ◽  
Focal Therapy ◽  
Multicenter Trial ◽  
Recurrent Prostate Cancer ◽  
Psma Pet ◽  
Management Changes ◽  
The Impact

292 Background: Prostate-specific membrane antigen ligand positron emission tomography (PSMA PET) induced management changes in up to every second patient in smaller clinical trials. We aim to determine the impact of 68Ga-PSMA-11 PET/CT on management of biochemically recurrent prostate cancer in a large prospective cohort. Methods: We report management changes following PSMA PET, a secondary endpoint of a prospective multicenter trial in men with prostate cancer biochemical recurrence (NCT02940262 and NCT03353740). Pre-PET, Post-PET and Post-Treatment Questionnaires were sent to referring physicians recording working clinical summaries, intended and implemented therapeutic and diagnostic management. Results: Intended management change occurred in 260/382 (68%) patients. Intended change was considered major in 176/382 (46%) patients. Management pathway aligned with PET findings, i.e. change towards local/focal therapy for locoregional disease (54/126 patients, 44%) and towards systemic therapy or combination approaches for metastatic disease (106/153 patients, 69%). Intended management was implemented in 160/206 (78%) patients. Perceived site of disease was unknown in 259/382 (68%) patients before and 111/382 (29%) patients after PSMA PET. A total of 150 intended diagnostic tests, mostly CT (n=43, 29%) and bone Scans/NaF-PET (n=52, 35%), were prevented by PSMA PET. A total of 73 tests, mostly biopsies (n=44, 60%) requested by the study protocol, were triggered. Conclusions: Disease localization by PSMA PET translated into management changes in more than half of patients with biochemical recurrence of prostate cancer. More than twice as many diagnostic tests were prevented than triggered following PET. Clinical trial information: NCT02940262 and NCT03353740.

Evaluation of the impact of public investment programs on social and economic performance of territories

2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena
Keyword(s):  
Bayesian Modeling ◽  
Positive Impact ◽  
Public Investment ◽  
Difference In Differences ◽  
The Public ◽  
Export Activity ◽  
Regional Investment ◽  
The Difference ◽  
The Impact ◽  
Development Institution

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.

Public space of the trustworthiness of sociological knowledge: The case of electoral research

2020 ◽  
pp. 13-22
Author(s):  
OLEKSANDR STEGNII
Keyword(s):  
Public Space ◽  
Research Process ◽  
Negative Influence ◽  
Election Campaign ◽  
Sociological Research ◽  
Good Tool ◽  
Sociological Knowledge ◽  
The Public ◽  
Approval Ratings ◽  
The Impact

The paper analyses specific features of sociological data circulation in a public space during an election campaign. The basic components of this kind of space with regard to sociological research are political actors (who put themselves up for the election), voters and agents. The latter refer to professional groups whose corporate interests are directly related to the impact on the election process. Sociologists can also be seen as agents of the electoral process when experts in the field of electoral sociology are becoming intermingled with manipulators without a proper professional background and publications in this field. In a public space where an electoral race is unfolding, empirical sociological research becomes the main form of obtaining sociological knowledge, and it is primarily conducted to measure approval ratings. Electoral research serves as an example of combining the theoretical and empirical components of sociological knowledge, as well as its professional and public dimensions. Provided that sociologists meet all the professional requirements, electoral research can be used as a good tool for evaluating the trustworthiness of results reflecting the people’s expression of will. Being producers of sociological knowledge, sociologists act in two different capacities during an election campaign: as analysts and as pollsters. Therefore, it is essential that the duties and areas of responsibility for professional sociologists should be separated from those of pollsters. Another thing that needs to be noted is the negative influence that political strategists exert on the trustworthiness of survey findings which are going to be released to the public. Using the case of approval ratings as an illustration, the author analyses the most common techniques aimed at misrepresenting and distorting sociological data in the public space. Particular attention is given to the markers that can detect bogus polling companies, systemic violations during the research process and data falsification.

The Use of Multimedia and its Impact on Bangladeshi EFL Learners at Tertiary Level

2020 ◽  
Vol 4 (2) ◽  
pp. 150
Author(s):  
Farzana Sharmin Pamela Islam
Keyword(s):  
Language Learning ◽  
Academic Writing ◽  
Teaching And Learning ◽  
English Language ◽  
Capital City ◽  
Tertiary Level ◽  
Language Classroom ◽  
The Difference ◽  
The Government ◽  
The Impact

As 21st century is the era of modern technologies with different aspects, it offers us to make the best use of them. After tape recorder and overhead projector (OHP), multimedia has become an important part of language classroom facilities for its unique and effective application in delivering and learning lesson. Although in many parts of Bangladesh, a South Asian developing country, where English enjoys the status of a foreign language, the use of multimedia in teaching and learning is viewed as a matter of luxury. However, nowadays the usefulness and the necessity of it are well recognized by the academics as well as the government. The study aims to focus on the difference between a traditional classroom void of multimedia and multimedia equipped classrooms at university level by explaining how multimedia support the students with enhanced opportunity to interact with diverse texts that give them more in-depth comprehension of the subject. It also focuses on audio-visual advantage of multimedia on the students’ English language learning. The study has followed a qualitative method to get an in-depth understanding of the impact of using multimedia in an English language classroom at tertiary level. For this purpose, the data have been collected from two different sources. Firstly, from students’ written response to  an open ended question as to their comparative experience of learning  lessons with and without multimedia facilities; and secondly, through  observation of English language classes at a private university of Dhaka, the capital city of Bangladesh. The discussion of the study is limited to  the use of multimedia in English language classroom using cartoons, images and music with a view to enhance students’ skills in academic writing, critical analysis of image and critical appreciation of music. For this purpose, cartoons in English language, images from Google and music from You Tube have got focused discussion in this paper.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

The Impact of Plant Bioactive Compounds on Aging and Fertility of Diverse Organisms: A Review

2020 ◽  
Vol 20 (13) ◽  
pp. 1287-1299
Author(s):  
Muhammad Akram Mohd Noordin ◽  
Mahanem Mat Noor ◽  
Wan Mohd Aizat
Keyword(s):  
Clinical Trial ◽  
Bioactive Compounds ◽  
Defense Mechanisms ◽  
Healthy Aging ◽  
Antioxidant Defense ◽  
Senior Citizens ◽  
Aging Population ◽  
Human Clinical Trial ◽  
Fertility Reduction ◽  
The Impact

It is expected that in 2050, there will be more than 20% of senior citizens aged over 60 years worldwide. Such alarming statistics require immediate attention to improve the health of the aging population. Since aging is closely related to the loss of antioxidant defense mechanisms, this situation eventually leads to numerous health problems, including fertility reduction. Furthermore, plant extracts have been used in traditional medicine as potent antioxidant sources. Although many experiments had reported the impact of various bioactive compounds on aging or fertility, there is a lack of review papers that combine both subjects. In this review, we have collected and discussed various bioactive compounds from 26 different plant species known to affect both longevity and fertility. These compounds, including phenolics and terpenes, are mostly involved in the antioxidant defense mechanisms of diverse organisms such as rats, mites, fruit flies, roundworms, and even roosters. A human clinical trial should be considered in the future to measure the effects of these bioactive compounds on human health and longevity. Ultimately, these plant-derived compounds could be developed into health supplements or potential medical drugs to ensure a healthy aging population.

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