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Skew deviation

Meghan K Cain, Zhiyong Zhang, Ke-Hai Yuan
Nonnormality of univariate data has been extensively examined previously (Blanca et al., Methodology: European Journal of Research Methods for the Behavioral and Social Sciences, 9(2), 78-84, 2013; Miceeri, Psychological Bulletin, 105(1), 156, 1989). However, less is known of the potential nonnormality of multivariate data although multivariate analysis is commonly used in psychological and educational research. Using univariate and multivariate skewness and kurtosis as measures of nonnormality, this study examined 1,567 univariate distriubtions and 254 multivariate distributions collected from authors of articles published in Psychological Science and the American Education Research Journal...
October 17, 2016: Behavior Research Methods
Barakat Adeola Animasahun, Akpoembele D Madise-Wobo, Bode A Falase, Samuel I Omokhodion
BACKGROUND: There are only very few reports on Fallot's tetralogy in Africa especially from sub-Saharan Africa. At best tetralogy of Fallot (TOF) is only mentioned as part of reports of surveys of other congenital heart diseases or as case reports in the region. There has been no report on cohorts of children with TOF in West Africa. This article describes the pattern and presentation of children diagnosed with TOF patients in a tertiary hospital in sub-Saharan Africa over a 9-year period...
October 2016: Cardiovascular Diagnosis and Therapy
Fredrik Strand, Keith Humphreys, Abbas Cheddad, Sven Törnberg, Edward Azavedo, John Shepherd, Per Hall, Kamila Czene
BACKGROUND: Interval breast cancers are often diagnosed at a more advanced stage than screen-detected cancers. Our aim was to identify features in screening mammograms of the normal breast that would differentiate between future interval cancers and screen-detected cancers, and to understand how each feature affects tumor detectability. METHODS: From a population-based cohort of invasive breast cancer cases in Stockholm-Gotland, Sweden, diagnosed from 2001 to 2008, we analyzed the contralateral mammogram at the preceding negative screening of 394 interval cancer cases and 1009 screen-detected cancers...
October 5, 2016: Breast Cancer Research: BCR
Jennifer A Nichols, Michael S Bednar, Robert M Havey, Wendy M Murray
At the wrist, kinematic coupling (the relationship between flexion-extension and radial-ulnar deviation) facilitates function. Although the midcarpal joint is critical for kinematic coupling, many surgeries, such as four-corner fusion (4CF) and scaphoid-excision four-corner fusion (SE4CF), modify the midcarpal joint. This study examines how 4CF and SE4CF influence kinematic coupling by quantifying wrist axes of rotation. Wrist axes of rotation were quantified in eight cadaveric specimens using an optimization algorithm, which fit a two-revolute joint model to experimental data...
October 5, 2016: Journal of Applied Biomechanics
Katsuya Mitamura, Yuka Yamamoto, Nobuyuki Kudomi, Yukito Maeda, Takashi Norikane, Keisuke Miyake, Yoshihiro Nishiyama
BACKGROUND: The nucleoside analog 3'-deoxy-3'-(18)F-fluorothymidine (FLT) has been investigated for evaluating tumor proliferating activity in brain tumors. We evaluated FLT uptake heterogeneity using textural features from the histogram analysis in patients with newly diagnosed gliomas and examined correlation of the results with proliferative activity and patient prognosis, in comparison with the conventional PET parameters. METHODS: FLT PET was investigated in 37 patients with newly diagnosed gliomas...
September 29, 2016: Annals of Nuclear Medicine
Darryl McClymont, Irvin Teh, Eric Carruth, Jeffrey Omens, Andrew McCulloch, Hannah J Whittington, Peter Kohl, Vicente Grau, Jürgen E Schneider
PURPOSE: The diffusion tensor model assumes Gaussian diffusion and is widely applied in cardiac diffusion MRI. However, diffusion in biological tissue deviates from a Gaussian profile as a result of hindrance and restriction from cell and tissue microstructure, and may be quantified better by non-Gaussian modeling. The aim of this study was to investigate non-Gaussian diffusion in healthy and hypertrophic hearts. METHODS: Thirteen rat hearts (five healthy, four sham, four hypertrophic) were imaged ex vivo...
September 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Meiyu Shen, Estelle Russek-Cohen, Eric V Slud
Bioequivalence (BE) studies are an essential part of the evaluation of generic drugs. The most common in vivo BE study design is the two-period two-treatment crossover design. AUC (area under the concentration-time curve) and Cmax (maximum concentration) are obtained from the observed concentration-time profiles for each subject from each treatment under each sequence. In the BE evaluation of pharmacokinetic crossover studies, the normality of the univariate response variable, e.g. log(AUC)(1) or log(Cmax), is often assumed in the literature without much evidence...
August 12, 2016: Journal of Biopharmaceutical Statistics
Su Joa Ahn, Jung Hoon Kim, Sang Joon Park, Joon Koo Han
PURPOSE: To determine whether baseline CT texture analysis of hepatic metastasis from colorectal cancer (CRC) is predictive of therapeutic response after cytotoxic chemotherapy. MATERIALS AND METHODS: 235 patients with liver metastasis from CRC who underwent CT and cytotoxic chemotherapy using FOLFOX and FOLFIRI were divided into derivation cohort (n=145) and validation cohort (n=90). The CT texture of the hepatic metastasis was quantified using baseline CT. We analyzed the independent predictor for the response from derivation cohort and validated it using validation cohort...
October 2016: European Journal of Radiology
Jason H Peragallo, Nancy J Newman
Diagnosing the underlying etiology of diplopia requires a structured approach. Double vision can arise from ocular, mechanical, or neurologic causes. A careful history can greatly improve a targeted examination. The approach to initial diagnosis and examination in cases of diplopia has been previously described. Here the authors expand upon those recommendations, and add new techniques recently described in the literature, which may influence the approach to the diplopia patient. A description of the approach to the examination of torsion is discussed...
August 2016: Seminars in Neurology
Shin C Beh, Teresa C Frohman, Elliot M Frohman
BACKGROUND: The cerebellum plays a central role in the online, real-time control, and long-term modulation of eye movements. EVIDENCE ACQUISITION: We reviewed the latest (fifth) edition of Leigh and Zee's textbook, The Neurology of Eye Movements, and literature in PUBMED using the following terms: cerebellum, flocculus, paraflocculus, vermis, oculomotor vermis, dorsal vermis, caudal fastigial nucleus, fastigial oculomotor region, uvula, nodulus, ansiform lobule, eye movements, saccades, ipsipulsion, contrapulsion, smooth pursuit, vergence, convergence, divergence, gaze-holding, down beat nystagmus, vestibulo-ocular reflex (VOR), angular VOR, translational VOR, skew deviation, velocity storage...
September 16, 2016: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
C C Thomas, D J Durian
We study experimentally the dynamics of granular media in a discharging hopper. In such flows, there often appears to be a critical outlet size D_{c} such that the flow never clogs for D>D_{c}. We report on the time-averaged velocity distributions, as well as temporal intermittency in the ensemble-averaged velocity of grains in a viewing window, for both D<D_{c} and D>D_{c}, near and far from the outlet. We characterize the velocity distributions by the standard deviation and the skewness of the distribution of vertical velocities...
August 2016: Physical Review. E
Mu He, Bastiaan Driehuys, Loretta G Que, Yuh-Chin T Huang
RATIONALE AND OBJECTIVES: Ventilation heterogeneity is impossible to detect with spirometry. Alternatively, pulmonary ventilation can be imaged three-dimensionally using inhaled (129)Xe magnetic resonance imaging (MRI). To date, such images have been quantified primarily based on ventilation defects. Here, we introduce a robust means to transform (129)Xe MRI scans such that the underlying ventilation distribution and its heterogeneity can be quantified. MATERIALS AND METHODS: Quantitative (129)Xe ventilation MRI was conducted in 12 younger (24...
September 8, 2016: Academic Radiology
Psang Dain Lin
Numerous optimization methods have been developed in recent decades for optical system design. However, these methods rely heavily on ray tracing and finite difference techniques to estimate the derivative matrices of the rays. Consequently, the accuracy of the results obtained from these methods is critically dependent on the incremental step size used in the tuning stage. To overcome this limitation, the present study proposes a comprehensive methodology for the design of compound dispersion prisms based on the first- and second-order derivative matrices of skew rays...
September 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Gu-Mu-Yang Zhang, Hao Sun, Bing Shi, Zheng-Yu Jin, Hua-Dan Xue
PURPOSE: To investigate the feasibility of using CT texture analysis (CTTA) to differentiate between low- versus high-grade urothelial carcinoma. METHODS: A total of 105 patients with high-grade urothelial carcinoma (HGUC, n = 106) and low-grade urothelial carcinoma (LGUC, n = 18) were included in this retrospective study. Both unenhanced and enhanced CT images representing the largest cross-sectional area of the tumor were chosen for CTTA performed using TexRAD software...
September 8, 2016: Abdominal Radiology
Frank Chen, Mittul Gulati, Darryl Hwang, Steven Cen, Felix Yap, Chidubem Ugwueze, Bino Varghese, Mihir Desai, Manju Aron, Inderbir Gill, Vinay Duddalwar
PURPOSE: The purpose of this study was to compare whole-lesion (WL) enhancement parameters to single region of interest (ROI)-based enhancement in discriminating clear cell renal cell carcinoma (ccRCC) from renal oncocytoma. MATERIALS AND METHODS: In this IRB-approved retrospective study, the surgical database was queried to derive a cohort of 94 postnephrectomy patients with ccRCC or oncocytoma (68 ccRCC, 26 oncocytoma), who underwent preoperative multiphase contrast-enhanced computed tomography (CECT) between June 2009 and August 2013...
September 6, 2016: Abdominal Radiology
Sharifah Halimah Jaafar, Jacqueline J Ho, Kim Seng Lee
BACKGROUND: Mother-infant proximity and interactions after birth and during the early postpartum period are important for breast-milk production and breastfeeding success. Rooming-in and separate care are both traditional practices. Rooming-in involves keeping the mother and the baby together in the same room after birth for the duration of hospitalisation, whereas separate care is keeping the baby in the hospital nursery and the baby is either brought to the mother for breastfeeding or she walks to the nursery...
2016: Cochrane Database of Systematic Reviews
Francesco Giganti, Sofia Antunes, Annalaura Salerno, Alessandro Ambrosi, Paolo Marra, Roberto Nicoletti, Elena Orsenigo, Damiano Chiari, Luca Albarello, Carlo Staudacher, Antonio Esposito, Alessandro Del Maschio, Francesco De Cobelli
OBJECTIVES: To investigate the association between preoperative texture analysis from multidetector computed tomography (MDCT) and overall survival in patients with gastric cancer. METHODS: Institutional review board approval and informed consent were obtained. Fifty-six patients with biopsy-proved gastric cancer were examined by MDCT and treated with surgery. Image features from texture analysis were quantified, with and without filters for fine to coarse textures...
August 23, 2016: European Radiology
Bela Büki, Manuela Hanschek, Heinz Jünger
OBJECTIVE: In this retrospective study, the aim of the authors was to examine the frequency of involvement of the individual semicircular canals (SCCs) in vestibular neuritis (VN) and to assess the degree of long-term recovery. A secondary aim was to retrospectively determine the usefulness of a three-step bedside oculomotor test (the HINTS-test) for the differential diagnosis of peripheral VN. METHODS: 44 cases were evaluated during the acute phase and approximately two months later...
August 18, 2016: Auris, Nasus, Larynx
Omer Jalil, Asim Afaq, Balaji Ganeshan, Uday B Patel, Darren Boone, Raymond Endozo, Ashley Groves, Bruce Sizer, Tan Arulampalam
AIM: The study aimed to investigate whether textural features of rectal cancer on magnetic resonance imaging (MRI) can predict long term survival in patients treated with long-course chemoradiotherapy. METHOD: Textural analysis (TA) using a filtration-histogram technique of T2-weighted pre- and six-week post chemoradiotherapy MRI was undertaken using TexRAD, a proprietary software algorithm. Regions of interest enclosing the largest cross-sectional area of the tumour were manually delineated on the axial images and filtration-step extracted features at different anatomical scales (fine, medium, and coarse) followed by quantification of statistical features (mean intensity, standard-deviation, entropy, skewness, kurtosis and mean of positive pixels [MPP]) using histogram analysis...
August 18, 2016: Colorectal Disease: the Official Journal of the Association of Coloproctology of Great Britain and Ireland
Xu Han, Shiteng Suo, Yawen Sun, Jinyan Zu, Jianxun Qu, Yan Zhou, Zengai Chen, Jianrong Xu
PURPOSE: To compare four methods of region-of-interest (ROI) placement for apparent diffusion coefficient (ADC) measurements in distinguishing low-grade gliomas (LGGs) from high-grade gliomas (HGGs). MATERIALS AND METHODS: Two independent readers measured ADC parameters using four ROI methods (single-slice [single-round, five-round and freehand] and whole-volume) on 43 patients (20 LGGs, 23 HGGs) who had undergone 3.0 Tesla diffusion-weighted imaging and time required for each method of ADC measurements was recorded...
August 16, 2016: Journal of Magnetic Resonance Imaging: JMRI
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