An Iterative Parametric Bootstrap Approach to Evaluating Rater Fit.

When analysts evaluate performance assessments, they often use modern measurement theory models to identify raters who frequently give ratings that are different from what would be expected, given the quality of the performance. To detect problematic scoring patterns, two rater fit statistics, the infit and outfit mean square error (MSE) statistics are routinely used. However, the interpretation of these statistics is not straightforward. A common practice is that researchers employ established rule-of-thumb critical values to interpret infit and outfit MSE statistics. Unfortunately, prior studies have shown that these rule-of-thumb values may not be appropriate in many empirical situations. Parametric bootstrapped critical values for infit and outfit MSE statistics provide a promising alternative approach to identifying item and person misfit in item response theory (IRT) analyses. However, researchers have not examined the performance of this approach for detecting rater misfit. In this study, we illustrate a bootstrap procedure that researchers can use to identify critical values for infit and outfit MSE statistics, and we used a simulation study to assess the false-positive and true-positive rates of these two statistics. We observed that the false-positive rates were highly inflated, and the true-positive rates were relatively low. Thus, we proposed an iterative parametric bootstrap procedure to overcome these limitations. The results indicated that using the iterative procedure to establish 95% critical values of infit and outfit MSE statistics had better-controlled false-positive rates and higher true-positive rates compared to using traditional parametric bootstrap procedure and rule-of-thumb critical values.

A New Multiplex Genetic Detection Assay Method for the Rapid Semi-Quantitative Detection of Six Common Curable Sexually Transmitted Pathogens From the Genital Tract.

Background: Sexually transmitted infections (STIs) are some of the most common communicable conditions and exert impact on the health and lives of many hundreds of millions of people across the world every year. Screening high-risk populations and conducting comprehensive detection tests would lead to a significant improvement in preventing the transmission of STIs and help us to provide rapid treatment to those affected. Here, we successfully established and validated a novel high-throughput multiplex gene detection system (HMGS) for the simultaneous and semiquantitative detection of six important curable sexually transmitted pathogens in a single reaction from secretions samples. Method: Fluorescently labeled primers were designed to target specific conserved and single-copy gene fragments of Ureaplasma urealyticum (U. urealyticum), Mycoplasma hominis (M. hominis), Chlamydia trachomatis (C. trachomatis), Neisseria gonorrhoeae (N. gonorrhoeae), Trichomonas vaginalis (T. vaginalis), and Treponema pallidum (T. pallidum). The specificity and sensitivity of the STI-HMGS was validated and optimized using plasmids and quantitative genomic DNA. Next, we validated the performances of the STI-HMGS for clinical application by testing samples of clinical secretions collected from patients who visited the gynecology and urology outpatient clinics of our reproductive medicine center. Results derived from the STI-HMGS were then compared with three approved commercialized kits that used to detect U. urealyticum, C. trachomatis and N. gonorrhoeae, respectively, followed by further validation with Sanger sequencing for all pathogens. Finally, a comprehensive analysis of epidemiology was performed among different subgroups to investigate the association between infection rates and clinically-relevant information. Results: The sensitivity of STI-HMGS for six target genes was 10 copies/µL. Data derived from the detection of 381 clinical secretions demonstrated that the STI-HMGS exhibited high concordance rate compared with approved commercialized kits and almost 100% sensitivity and specificity for the detection of six sexually transmitted pathogens when validated by Sanger sequencing. Semi-quantitative analysis found that STIs caused by N. gonorrhoeae had a significantly higher (P<0.05) pathogen load than the other pathogens. Infections caused by C. trachomatis were significantly more common in younger individuals (P<0.05). We also found that U. urealyticum infections were more likely to happen in females; while the males were more affected by N. gonorrhoeae (P<0.05). Conclusions: STI-HMGS proved to be an efficient method for the semi-quantitative detection of six important curable sexually transmitted pathogens and therefore represents an alternative method for the clinical detection and monitoring of STIs.

The positive rates of hepatitis B surface antibody in youth after booster vaccination: a 4-year follow-up study with large sample.

BACKGROUND: Hepatitis B virus (HBV) infection is still a public issue in the world. Hepatitis B vaccination is widely used as an effective measure to prevent HBV infection. This large-sample study aimed to evaluate the positive rates of hepatitis B surface antibody (anti-HBs) in youth after booster vaccination. METHODS: A total of 37788 participants were divided into two groups according to the baseline levels of anti-HBs before booster vaccination: the negative group (anti-HBs(-)) and the positive group (anti-HBs(+)). Participants were tested for anti-HBs levels after receiving a booster vaccine at 1 and 4 years. RESULTS: The positive rates of anti-HBs were 34.50%, 73.80% and 67.32% before booster vaccination at 1 and 4 years after vaccination, respectively. At 4 years after the booster vaccination, the positive rates of 13-18 years were 47.54%, which was the lowest level among all youth age groups. In the anti-HBs(-) group, the positive conversion rates of anti-HBs were 74.62% at 1 year after receiving a booster vaccine, and 67.66% at 4 years after vaccination. In the anti-HBs(+) group, the positive maintenance rates of anti-HBs were 70.16% after 1 year, and 66.66% after 4 years. Compared with the baseline anti-HBs (+) group, the positive rates of the baseline anti-HBs(-) group were higher at 1 and 4 years after receiving the booster vaccine. CONCLUSION: The positive rates of anti-HBs declined over time, especially the positive maintenance rates were the lowest at age of 13-18 years.

Equitable Thresholding and Clustering: A Novel Method for Functional Magnetic Resonance Imaging Clustering in AFNI.

This article describes a hybrid method to threshold functional magnetic resonance imaging (FMRI) group statistical maps derived from voxel-wise second-level statistical analyses. The proposed "Equitable Thresholding and Clustering" (ETAC) approach seeks to reduce the dependence of clustering results on arbitrary parameter values by using multiple subtests, each equivalent to a standard FMRI clustering analysis, to make decisions about which groups of voxels are potentially significant. The union of these subtest results decides which voxels are accepted. The approach adjusts the cluster-thresholding parameter of each subtest in an equitable way, so that the individual false-positive rates (FPRs) are balanced across subtests to achieve a desired final FPR (e.g., 5%). ETAC utilizes resampling methods to estimate the FPR and thus does not rely on parametric assumptions about the spatial correlation of FMRI noise. The approach was validated with pseudotask timings in resting-state brain data. In addition, a task FMRI data collection was used to compare ETACs true positive detection power versus a standard cluster detection method, demonstrating that ETAC is able to detect true results and control false positives while reducing reliance on arbitrary analysis parameters.

Specificity rates for non-clinical, bilingual, Mexican Americans with California Verbal Learning Test3, verbal fluency, and Rey 15-IR performance validity measures.

Objective: To measure failure rates among non-clinical, Mexican American, bilinguals on embedded performance validity measures from the California Verbal Learning Test3 and verbal fluency and the stand-alone Rey 15-item test plus recognition (Rey 15-IR) using valid/invalid performance cut scores developed for monolingual, English-speakers. Method: Participants were 60 consecutive recruits, aged between 18 and 75 years, with ≤16 years of education who self-identified as bilingual (confirmed via formal assessment) and chose the language of assessment, Spanish or English, for the performance validity tests. Results: The only performance validity measure studied with a higher failure rate (19%) than that for monolingual, English-speakers (9%) was semantic fluency administered in Spanish. Conclusions: Valid/invalid performance cut scores derived for monolingual English-speakers generated comparable or lower failure rates among Mexican American bilinguals on CVLT3 forced-choice recognition, CVLT3 yes-no recognition hits, letter fluency, semantic fluency in English, and the Rey 15-IR.

FMRI Clustering in AFNI: False-Positive Rates Redux.

Recent reports of inflated false-positive rates (FPRs) in FMRI group analysis tools by Eklund and associates in 2016 have become a large topic within (and outside) neuroimaging. They concluded that existing parametric methods for determining statistically significant clusters had greatly inflated FPRs ("up to 70%," mainly due to the faulty assumption that the noise spatial autocorrelation function is Gaussian shaped and stationary), calling into question potentially "countless" previous results; in contrast, nonparametric methods, such as their approach, accurately reflected nominal 5% FPRs. They also stated that AFNI showed "particularly high" FPRs compared to other software, largely due to a bug in 3dClustSim. We comment on these points using their own results and figures and by repeating some of their simulations. Briefly, while parametric methods show some FPR inflation in those tests (and assumptions of Gaussian-shaped spatial smoothness also appear to be generally incorrect), their emphasis on reporting the single worst result from thousands of simulation cases greatly exaggerated the scale of the problem. Importantly, FPR statistics depends on "task" paradigm and voxelwise p value threshold; as such, we show how results of their study provide useful suggestions for FMRI study design and analysis, rather than simply a catastrophic downgrading of the field's earlier results. Regarding AFNI (which we maintain), 3dClustSim's bug effect was greatly overstated-their own results show that AFNI results were not "particularly" worse than others. We describe further updates in AFNI for characterizing spatial smoothness more appropriately (greatly reducing FPRs, although some remain >5%); in addition, we outline two newly implemented permutation/randomization-based approaches producing FPRs clustered much more tightly about 5% for voxelwise p ≤ 0.01.

Specificity rates for non-clinical, bilingual, Mexican Americans on three popular performance validity measures.

OBJECTIVE: To measure specificity as failure rates for non-clinical, bilingual, Mexican Americans on three popular performance validity measures: (a) the language format Reliable Digit Span; (b) visual-perceptual format Test of Memory Malingering; and (c) visual-perceptual format Dot Counting, using optimal/suboptimal effort cut scores developed for monolingual, English-speakers. METHODS: Participants were 61 consecutive referrals, aged between 18 and 65 years, with <16 years of education who were subjectively bilingual (confirmed via formal assessment) and chose the language of assessment, Spanish or English, for the performance validity tests. RESULTS: Failure rates were 38% for Reliable Digit Span, 3% for the Test of Memory Malingering, and 7% for Dot Counting. For Reliable Digit Span, the failure rates for Spanish (46%) and English (31%) languages of administration did not differ significantly. CONCLUSIONS: Optimal/suboptimal effort cut scores derived for monolingual English-speakers can be used with Spanish/English bilinguals when using the visual-perceptual format Test of Memory Malingering and Dot Counting. The high failure rate for Reliable Digit Span suggests it should not be used as a performance validity measure with Spanish/English bilinguals, irrespective of the language of test administration, Spanish or English.

The prevalence of hypertension in population of Keshan disease endemic areas in China, 2009 / 中华地方病学杂志

Objective To survey the prevalence of hypertension in population of Keshan disease endemic areas, in order to provide a scientific basis for prevention and control of hypertension in rural areas of our country.Methods One hundred and twenty villages were selected as the survey places based on case-finding from 15 provinces including Gansu, Hebei, Henan, Heilongjiang, Jilin, Liaoning, Shaanxi, Shandong, Shanxi, Hubei, Yunnan,Sichuan, Guizhou, Chongqing and Mongolia in 2009.The subjects were permanent residents in the survey places.Basic situation of all subjects was collected through the questionnaire survey and blood pressure was measured by a clinician.Diagnostic criterion for hypertension was based on the Chinese Guidelines for the Management of Hypertension.Results Totally 33 558 subjects aged 18 and over were surveyed, including 8 699 hypertension patients.The positive rate of hypertension was 25.9％ (8 699/33 558), among that 26.3％ (3 532/13 408) were males,and 25.6％ (5 167/20 150) were females.The positive rate of hypertension increased with age (x2 =3 348.325, P ＜0.05).In the classification of hypertension, the proportion of stage 1, 2 and 3 hypertension and isolated systolic hypertension was 31.8％ (2 770/8 699), 26.1％ (2 273/8 699), 17.2％ (1 492/8 699) and 24.9％ (2 164/8 699),respectively.Conclusions The positive rates of hypertension in Keshan disease endemic areas are higher than those of the national average (18.8％).Hypertension is a serious public health problem in Keshan disease endemic areas.The strategy of hypertension prevention and control should be formulated for remote rural areas.

Nonparametric Independence Screening in Sparse Ultra-High Dimensional Varying Coefficient Models.

The varying-coefficient model is an important class of nonparametric statistical model that allows us to examine how the effects of covariates vary with exposure variables. When the number of covariates is large, the issue of variable selection arises. In this paper, we propose and investigate marginal nonparametric screening methods to screen variables in sparse ultra-high dimensional varying-coefficient models. The proposed nonparametric independence screening (NIS) selects variables by ranking a measure of the nonparametric marginal contributions of each covariate given the exposure variable. The sure independent screening property is established under some mild technical conditions when the dimensionality is of nonpolynomial order, and the dimensionality reduction of NIS is quantified. To enhance the practical utility and finite sample performance, two data-driven iterative NIS methods are proposed for selecting thresholding parameters and variables: conditional permutation and greedy methods, resulting in Conditional-INIS and Greedy-INIS. The effectiveness and flexibility of the proposed methods are further illustrated by simulation studies and real data applications.

Additive effect of factors related to assisted conception on the reduction of maternal serum pregnancy-associated plasma protein A concentrations and the increased false-positive rates in first-trimester Down syndrome screening.

OBJECTIVE: To analyze whether assisted conceptions need adjustments in first-trimester Down syndrome screening and why modifications in screening markers occur. DESIGN: Eleven-year cohort retrospective analysis. SETTING: Maternal-fetal medicine unit. PATIENT(S): Two thousand eleven naturally conceived normal singleton pregnancies and 2,042 normal singleton pregnancies achieved with assisted conception: 350 by IUI and 1,692 with IVF (n = 328) or intracytoplasmic sperm injection (ICSI; n = 1,364), using nondonor (n = 1,086) or donated ova (n = 606), with fresh (n = 1,432) or frozen (n = 260) embryos. INTERVENTION(S): Comparison of ultrasound and biochemical markers of first-trimester Down syndrome screening according to the mode of conception and considering the clinical and laboratory parameters related. MAIN OUTCOME MEASURE(S): Nuchal translucency (NT), PAPP-A and free ßhCG maternal serum concentrations, and false-positive rates (FPRs). RESULT(S): NT is unaffected by the mode of conception. Singleton pregnancies achieved by IVF and ICSI with nondonor oocytes have reduced maternal serum PAPP-A and increased FPR, which are significant only in ICSI cycles. Pregnancies from frozen embryos with hormone therapy also show decreased PAPP-A but without affecting the FPR. Elevated maternal serum fßhCG levels in oocyte donation do not influence the FPR. CONCLUSION(S): Among assisted conceptions, only nondonor IVF/ICSI singleton pregnancies need adjustments of the maternal serum PAPP-A in first-trimester Down syndrome screening.

Positive rates of 2009 novel influenza A (H1N1) was high in school-aged individuals: significance in pandemic control.

In this study, data from a pandemic H1N1 outbreak in Korea were analyzed according to time, geography (districts), and age. A total of 252,271 samples collected nationwide were referred to the Greencross Reference Laboratory from June 2009 to February 2010 for H1N1 confirmation testing. Of these samples, 105,300 (41.7%) were H1N1-positive. With time, positivity was highest (57.0%) from October 26 - November 1 (4 weeks after Chuseok). The positive rates among districts show the highest value in Ulsan City (63.1%) and the lowest in Gyeongnam Province (32.8%). The positive rates for ages 0-2, 3-5, 6-11, 12-17, 18-20, 21-30, 31-40, 41-50, 51-60, and > 60 yr were 17.0%, 33.1%, 56.2%, 55.5%, 55.3%, 41.5%, 28.2%, 30.5%, 31.1%, and 16.8%, respectively, indirectly indicating propagation of H1N1 through schools. Pandemic control should involve school-targeted strategies.

Positive Rates of 2009 Novel Influenza A (H1N1) was High in School-Aged Individuals: Significance in Pandemic Control

In this study, data from a pandemic H1N1 outbreak in Korea were analyzed according to time, geography (districts), and age. A total of 252,271 samples collected nationwide were referred to the Greencross Reference Laboratory from June 2009 to February 2010 for H1N1 confirmation testing. Of these samples, 105,300 (41.7%) were H1N1-positive. With time, positivity was highest (57.0%) from October 26 - November 1 (4 weeks after Chuseok). The positive rates among districts show the highest value in Ulsan City (63.1%) and the lowest in Gyeongnam Province (32.8%). The positive rates for ages 0-2, 3-5, 6-11, 12-17, 18-20, 21-30, 31-40, 41-50, 51-60, and > 60 yr were 17.0%, 33.1%, 56.2%, 55.5%, 55.3%, 41.5%, 28.2%, 30.5%, 31.1%, and 16.8%, respectively, indirectly indicating propagation of H1N1 through schools. Pandemic control should involve school-targeted strategies.

A Study on the Prevalence of HBsAg and Anti-HCV in Patients with Hepatocellular Carcinoma: Comparative Study with Healthy Blood Donors / 대한임상병리학회지

BACKGROUND: The aim of this study was to evaluate the positive rates of hepatitis B surface antigen (HBsAg) and antibody to hepatitis C virus (anti-HCV) in patients with hepatocellular carcinoma (HCC), and to estimate the risk of developing HCC in association with HBsAg or anti- HCV positivity. METHODS: HBsAg and anti-HCV (anti-c22-3 and anti-c200) were tested by enzyme immunoassay in 892 patients with HCC from 1991 to 1994. Data regarding the prevalence of these hepatitis markers in 4,269 healthy blood donors were obtained from the Central Blood Center of the Korea Red Cross and used for case-control study. RESULTS: The positive rate of HBsAg was 72.3% (645/892) in patients with HCC and 2.7% (117/ 4,269) in blood donors, while that of anti-HCV was 7.6% (68/892) in patients with HCC and 0.3% (11/4,269) in blood donors. Six hundreds and thirty-six among 892 patients with HCC (71.3%) were only positive for HBsAg, 59 (6.6%) were only anti-HCV positive, and 9 (1.0%) were positive for both HBsAg and anti-HCV. The odds ratio (with 95% confidence interval: CI) comparing patients with HCC to healthy blood donors were 17.8 (CI: 4.7-61.5) for HBsAg positive, 11.9 (CI: 2.8-52.2) for anti-HCV positive, and 208.9 (CI: 18.6-2,345.7) for both HBsAg and anti-HCV positive. The risk estimates for both HBsAg and anti-HCV positve were not different from those for HBsAg positive or anti-HCV positive because the confidence interval of patients with both HBsAg and anti-HCV positive overlapped that of patients with HBsAg positive, or that of patients with anti-HCV positive. CONCLUSIONS: Our results suggested that HBsAg was more important risk factor of HCC than anti-HCV and there was no interaction between HBsAg and anti-HCV in the development of HCC.