LLukas22/scidocs huggingface dataset:
Bias, precision and statistical power of analysis of covariance in the analysis of randomized trials with baseline imbalance: a simulation study

BACKGROUND
Analysis of variance (ANOVA), change-score analysis (CSA) and analysis of covariance (ANCOVA) respond differently to baseline imbalance in randomized controlled trials. However, no empirical studies appear to have quantified the differential bias and precision of estimates derived from these methods of analysis, and their relative statistical power, in relation to combinations of levels of key trial characteristics. This simulation study therefore examined the relative bias, precision and statistical power of these three analyses using simulated trial data.


METHODS
126 hypothetical trial scenarios were evaluated (126,000 datasets), each with continuous data simulated by using a combination of levels of: treatment effect; pretest-posttest correlation; direction and magnitude of baseline imbalance. The bias, precision and power of each method of analysis were calculated for each scenario.


RESULTS
Compared to the unbiased estimates produced by ANCOVA, both ANOVA and CSA are subject to bias, in relation to pretest-posttest correlation and the direction of baseline imbalance. Additionally, ANOVA and CSA are less precise than ANCOVA, especially when pretest-posttest correlation ≥ 0.3. When groups are balanced at baseline, ANCOVA is at least as powerful as the other analyses. Apparently greater power of ANOVA and CSA at certain imbalances is achieved in respect of a biased treatment effect.


CONCLUSIONS
Across a range of correlations between pre- and post-treatment scores and at varying levels and direction of baseline imbalance, ANCOVA remains the optimum statistical method for the analysis of continuous outcomes in RCTs, in terms of bias, precision and statistical power.
Face Recognition using

We tried to develop a real time face detection and recognition system which uses an “appearance-based” approach. For detection purpose we used Viola Jones algorithm. To recognize face we worked with Eigen Faces which is a PCA based algorithm. In a real time to recognize a face we need a data training set. For data training set we took five images of each person and manipulated the Eigen values to match the known individual.
Learning N-Gram Language Models from Uncertain Data

We present a new algorithm for efficiently training n-gram language models on uncertain data, and illustrate its use for semisupervised language model adaptation. We compute the probability that an n-gram occurs k times in the sample of uncertain data, and use the resulting histograms to derive a generalized Katz back-off model. We compare three approaches to semisupervised adaptation of language models for speech recognition of selected YouTube video categories: (1) using just the one-best output from the baseline speech recognizer or (2) using samples from lattices with standard algorithms versus (3) using full lattices with our new algorithm. Unlike the other methods, our new algorithm provides models that yield solid improvements over the baseline on the full test set, and, further, achieves these gains without hurting performance on any of the set of video categories. We show that categories with the most data yielded the largest gains. The algorithm has been released as part of the OpenGrm n-gram library [1].
Quaternion Based Inverse Kinematics for Industrial Robot Manipulators with Euler Wrist

The major complications of inverse kinematics problem for serial robot manipulators are singularities and nonlinearities. In this context, it is important to formulize the inverse problem in a compact closed form. In this paper, we present closed form solutions of the 6-DOF industrial robot manipulators with Euler wrist using dual quaternions. The successive screw displacements in dual quaternions reduce sine/cosine-type nonlinearities, resulting in a very compact formulation. The RS, RN, and NS robot manipulators are considered as the examples of the employed method
Long-term Outcomes of Ulnar Shortening Osteotomy for Idiopathic Ulnar Impaction Syndrome: At Least 5-Years Follow-up

BACKGROUND
There have been few outcomes studies with follow-up after performing ulnar shortening osteotomy for ulnar impaction syndrome. We investigated the long-term clinical and radiological outcomes of ulnar shortening osteotomy for the treatment of idiopathic ulnar impaction syndrome.


METHODS
We retrospectively reviewed 36 patients who had undergone ulnar shortening osteotomy for idiopathic ulnar impaction syndrome for a mean follow-up of 79.1 months (range, 62 to 132 months). The modified Gartland and Werley scores were measured pre- and postoperatively. The radiographic parameters for the assessment of the distal radioulnar joint (DRUJ) as well as the relationship between these radiographic parameters and the clinical and radiological outcomes were determined.


RESULTS
The average modified Gartland and Werley wrist score improved from 65.5 ± 8.1 preoperatively to 93.4 ± 5.8 at the last follow-up visit. The average preoperative ulnar variance of 4.7 ± 2.0 mm was reduced to an average of -0.6 ± 1.4 mm postoperatively. Osteoarthritic changes of the DRUJ were first seen at 34.8 ± 11.1 months follow-up in 6 of 36 wrists (16.7%). Those who had osteoarthritic changes in the DRUJ had significantly wider preoperative ulnar variance, a longer distal radioulnar distance and a greater length of ulnar shortening, but the wrist scores of the patients who had osteoarthritic changes in the DRUJ were comparable to those who did not have osteoarthritic changes in the DRUJ.


CONCLUSIONS
The clinical outcomes are satisfactory for even more than 5 years after ulnar shortening osteotomy for treating idiopathic ulnar impaction syndrome despite the osteoarthritic changes of the DRUJ. The patients who need a larger degree of ulnar shortening may develop DRUJ arthritis.
Secure communication for the Internet of Things - a comparison of link-layer security and IPsec for 6LoWPAN

The future Internet is an IPv6 network interconnecting traditional computers and a large number of smart objects. This Internet of Things (IoT) will be the foundation of many services and our daily life will depend on its availability and reliable operation. Therefore, among many other issues, the challenge of implementing secure communication in the IoT must be addressed. In the traditional Internet, IPsec is the established and tested way of securing networks. It is therefore reasonable to explore the option of using IPsec as a security mechanism for the IoT. Smart objects are generally added to the Internet using IPv6 over Low-power Wireless Personal Area Networks (6LoWPAN), which defines IP communication for resource-constrained networks. Thus, to provide security for the IoT based on the trusted and tested IPsec mechanism, it is necessary to define an IPsec extension of 6LoWPAN. In this paper, we present such a 6LoWPAN/IPsec extension and show the viability of this approach. We describe our 6LoWPAN/IPsec implementation, which we evaluate and compare with our implementation of IEEE 802.15.4 link-layer security. We also show that it is possible to reuse crypto hardware within existing IEEE 802.15.4 transceivers for 6LoWPAN/IPsec. The evaluation results show that IPsec is a feasible option for securing the IoT in terms of packet size, energy consumption, memory usage, and processing time. Furthermore, we demonstrate that in contrast to common belief, IPsec scales better than link-layer security as the data size and the number of hops grow, resulting in time and energy savings. Copyright © 2012 John Wiley & Sons, Ltd.
Comparisons between GalileoSat and Global Navigation Flower Constellations

Flower constellation design scheme was applied to design new global navigation system constellations called GNFCs. To investigate the possibility of reduced number of satellites in a GNFC, both genetic algorithms and flower constellation schemes are applied to find optimality. The proposed optimal GNFCs are then compared with GalileoSat constellation. New approach shows the better navigation performance than that of GalileoSat constellation
Comparison of the correlation of rebreathing method and echocardiography in heart failure patients with moderate to severe mitral regurgitation.

OBJECTIVE
To follow-up and estimate cardiac function in 11 heart failure patients with moderate to severe mitral regurgitation who underwent cardiac resynchronization therapy (CRT) and to compare echocardiography to the rebreathing method (indirect Fick method) which were used for estimation.


DESIGN
Prospective, observational, clinical study.


SETTING
University teaching hospital.


METHODS
Eleven cases (8 males and 3 females) were selected and followed-up during presurgery, postsurgery, and 1, 3, and 6 months after pacemaker implantation. Stroke volume was measured by echocardiography (Simpson's method and velocity-time integral method) and rebreathing each time.


RESULTS
Correlations were found between stroke volume with the rebreathing method (RSV) and stroke volume with the velocity-time integral (VSV), R = 0.89, although ANOVA, the q test, and paired t test showed no statistical differences between them. Stroke volume with Simpson's rule (SSV) was poorly correlated with stroke volume using the Indirect Fick method (RSV) and with stroke volume using the velocity-time integral method (VSV) (R = 0.58 and 0.54, respectively).


CONCLUSION
The rebreathing method (indirect FICK method) and velocity-time integral method are noninvasive methods with which to measure cardiac function and exhibited good correlation during the follow-up study.
Remittances, Exchange Rate Regimes, and the Dutch Disease: A Panel Data Analysis

Using disaggregated sectorial data, this study shows that rising levels of remittances have spending effects that lead to real exchange rate appreciation and resource movement effects that favor the nontradable sector at the expense of tradable goods production. These characteristics are two aspects of the phenomenon known as Dutch disease. The results further indicate that these effects operate more strongly under fixed nominal exchange rate regimes. JEL classification: F24, F31, O10
Fast overflow probability estimation tool for MPLS networks

The constant growth of internet and the variety of services provided makes the estimation of QoS parameters a fundamental need for every Internet Service Provider. The present work introduces a software tool that calculates the overflow probability on the core links of a MPLS network. The calculation is based on the statistical properties of the arriving traffic and the routing on the network. The procedure uses the results of the large deviations theory and the work of Likhanov et al. [22] for small buffer. The results obtained show high degree of accuracy as well as very short processing times. This allows the user to determine the overflow status of the network without the need to use the traditional highly time consuming simulation techniques.
Using eye-tracking technology to investigate the redundant effect of multimedia web pages on viewers' cognitive processes

This study utilized eye-tracking technology to determine the impact of redundant onscreen text information on viewers’ cognitive processes with respect to multimedia information. Sixteen college students participated in the study and their eye-movement data and self-reported cognitive load ratings were collected as they viewed three web pages into which different forms of verbal explanations of thunderstorm systems were integrated. A repeated measure design was utilized to support the research purposes. The eye-tracking data showed that viewers relied on text information as the main information resource for determining meaning. Students’ cognitive load reports reflected a redundant effect from the on screen text on their cognitive load level when both onscreen and narrative verbal messages were presented. However, eye-movement data revealed that viewers spent less time on the onscreen text when there was a narrative message presenting the same information. When the pictorial information was accompanied by both onscreen and narrative formats of verbal information, viewers seemed to be able to filter out redundant information. Additionally, replacing onscreen text with a voice-over seemed to globally orient viewers’ eye fixations toward the illustration. Discussions on results and suggestions for future studies are provided in this paper. 2011 Elsevier Ltd. All rights reserved.
[Effect of an integral care system: a combination of oriental and western care for older adults with degenerative arthritis].

PURPOSE
This study was done to examine the effect of an integrated care service which included a combination of oriental and western care on health outcomes in elderly patients with degenerative arthritis.


METHODS
A prospective comparative design was used. Data were collected from May 1, 2008 to June 30, 2009 from 85 elderly patients with degenerative arthritis in the lower extremities who were followed in a hospital out-patient department for 8 weeks. The integrated care service group (n=36) received a combination of physical therapy, acupuncture, western medicines or herbal medicines, and the western care group (n=49) received physical therapy or western medicines. Functional independence, walking speed, rotation balance, pain intensity, service satisfaction and total medical costs for the two groups were compared at 8 weeks.


RESULTS
Functional independence (t=2.14, p=.036) and walking speed (t=2.51, p=.014) improved significantly in the integrated care group while pain intensity improved significantly in the western care group (t=3.35, p=.002). The integrated care group reported higher scores for service satisfaction (t=2.09, p=.041) and higher medical costs than the western care group (t=2.15, p=.035).


CONCLUSION
The results suggest that integrated care services are effective modalities to improve mobility and quality of life for elders with degenerative arthritis.
Assessing the bias in samples of large online networks

We consider the sampling bias introduced in the study of online networks when collecting data through publicly available APIs (application programming interfaces). We assess differences between three samples of Twitter activity; the empirical context is given by political protests taking place in May 2012. We track online communication around these protests for the period of one month, and reconstruct the network of mentions and re-tweets according to the search and the streaming APIs, and to different filraph comparison tering parameters. We find that smaller samples do not offer an accurate picture of peripheral activity; we also find that the bias is greater for the network of mentions, partly because of the higher influence of snowballing in identifying relevant nodes. We discuss the implications of this bias for the study of diffusion dynamics and political communication through social media, and advocate the need for more uniform sampling procedures to study online communication. © 2014 Elsevier B.V. All rights reserved.
Impact of the pre-transplant histological score on 3-year graft outcomes of kidneys from marginal donors: a single-centre study.

BACKGROUND
The reliability of kidney biopsy as the sole means for assessing kidneys from extended-criteria donors (ECDs) to be allocated to single or dual transplantation is still a matter of debate.


METHODS
We compared retrospectively 3 years graft survival and renal function in 44 recipients of a single kidney graft from a marginal donor with good renal function and a Karpinski histological score of ≤ 3 and 56 recipients of a single transplant with a Karpinski score of 4 or 5. The donors' and recipients' characteristics were compared by means of Wilcoxon's rank-sum test and Fisher's exact test, and survival was analysed using the log-rank test and Cox regression survival analysis.


RESULTS
The donors with the worse histological scores were slightly younger (68.0 ± 4.74 versus 71.3 ± 4.6 years, P < 0.01) and had a higher glomerular filtration rate (85.8 ± 28.2 versus 76.3 ± 26.53 mL/min, P = 0.013), but there was no difference in serum creatinine levels (0.83 ± 0.24 versus 0.85 ± 0.30 mg/dL, P = 0.381). Three years after transplantation, there was no difference between the two groups in terms of recipient serum creatinine levels (1.94 ± 0.69 versus 1.74 ± 0.49 mg/dL, P = 0.134), estimated glomerular filtration rate (eGFR, 45.6 ± 21.1 versus 51.7 ± 22.0 mL/min, P = 0.331) or the rates of graft loss (27.3 versus 35.7%, P = 0.47), delayed graft function or acute rejection.


CONCLUSIONS
In our experience, provided the donor has a normal renal function, a difference in the pre-transplant histological score of kidneys from marginal cadaveric donors do not have a significant influence on the outcome 3 years after transplantation. Our findings might represent a basis for designing a randomized controlled trial of using a higher histological score threshold for the DKT allocation of grafts from ECDs with a normal renal function.
An assessment of the Nam Pehchan computer program for the identification of names of south Asian ethnic origin.

BACKGROUND
An assessment was made of the usefulness and accuracy of a computer program for the identification of the south Asian population through the classification of names on a disease register.


METHODS
The computer program, Nam Pehchan, was used to classify names as either south Asian or non south Asian. The results were compared with a reference standard, which combined use of the program with visual inspection. The latter was facilitated by a computer-generated dictionary of common non south Asian names. The data set consisted of 356,555 cases of incident cancer (ICD9: 140-208) registered between 1990 and 1992 by Thames, Trent, West Midlands and Yorkshire cancer registries.


RESULTS
Nam Pehchan classified 5506 cases as south Asian. Visual inspection identified 2024 false positives (36.8 per cent of all cases identified as south Asian by Nam Pehchan) and 363 false negatives (9.5 per cent of those identified by the reference standard). Compared with the reference standard, Nam Pehchan had a sensitivity of 90.5 per cent and a positive predictive value of 63.2 per cent.


CONCLUSION
The Nam Pehchan program quickly identified a high proportion of the names classified as south Asian by the reference standard, but the high false positive rate means that the program alone is not an adequate single strategy. The time-consuming process of inspection of program negatives for large data sets can be substantially reduced by comparison with dictionaries of common non south Asian names.
Does random urine drug testing reduce illicit drug use in chronic pain patients receiving opioids?

BACKGROUND
Prescription drug abuse and illicit drug use are common in chronic pain patients. Adherence monitoring with screening tests, and urine drug testing, periodic monitoring with prescription monitoring programs, has become a common practice in recent years. Random drug testing for appropriate use of opioids and use of illicit drugs is often used in pain management practices. Thus, it is expected that random urine drug testing will deter use of illicit drugs, and also improve compliance.


OBJECTIVES
To study the prevalence of illicit drug use in patients receiving opioids for chronic pain management and to compare the results of illicit drug use with the results from a previous study.


DESIGN
A prospective, consecutive study.


SETTING
Interventional pain management practice setting in the United States.


METHODS
A total of 500 consecutive patients on opioids, considered to be receiving stable doses of opioids supplemental to their interventional techniques, were studied by random drug testing. Testing was performed by rapid drug screen. Results were considered positive if one or more of the monitored illicit drugs including cocaine, marijuana (THC), methamphetamine or amphetamines were present.


RESULTS
Illicit drug use was evident in 80 patients, or 16%, with marijuana in 11%, cocaine in 5%, and methamphetamine and/or amphetamines in 2%. When compared with previous data, the overall illicit drug use was significantly less. Illicit drug use in elderly patients was absent.


CONCLUSION
The prevalence of illicit drug abuse in patients with chronic pain receiving opioids continues to be a common occurence. This study showed significant reductions in overall illicit drug use with adherence monitoring combined with random urine drug testing.
Enhancement of dielectric constant in polymer-ceramic nanocomposite for flexible electronics and energy storage applications

Abstract The polymer nanocomposites have potential applications in flexible electronics due to its interesting dielectric properties. Hence, flexible nanocomposite films of polyvinylidene fluoride (PVDF) polymer and barium hexaferrite (BHF) nanoparticles with high dielectric constant were prepared by the solution cast method. The dielectric behavior of the materials has been understood by employing the impedance spectroscopy technique. The co-existence of α and β phases of PVDF has been observed from the XRD (X-ray Diffractometer) and FTIR (Fourier-transform infrared spectroscopy) analysis. The ratio of α and β phases of PVDF has a great influence on dielectric, ferroelectric and energy storage density of PVDF-BHF nanocomposites and, it depends upon the concentration of BHF in the nanocomposites. FE-SEM (Field Emission Scanning Electron Microscopy) micrographs reveal that the microstructure of the composite depends upon the concentration of BHF in the PVDF matrix. Dielectric properties of nanocomposite highly depends on microstructure of the PVDF-BHF nanocomposite. This observation has been well explained by considering the BLCs (Barrier Layer capacitances) model. Interestingly, the dielectric constant has been enhanced eighteen (18) times at 1 KHz to that of dielectric constant of PVDF. The dielectric constant increases due to the electrostatics and interfacial interaction between the local electric field of the BHF nanoparticle and CH2/CF2 dipole of PVDF chain. The present study opens a new window for the possible use of PVDF-BHF nanocomposite in dielectric and energy storage device applications.