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Sample records for random structure prior

  1. Integrating prior knowledge and structure from motion

    DEFF Research Database (Denmark)

    Guilbert, Nicolas; Aanæs, Henrik; Larsen, Rasmus

    2001-01-01

    A new approach for formulating prior knowledge in structure form motion is presented, where the structure is viewed as a 3D stochastic variable, hereby priors are more naturally expressed. It is demonstrated that this formulation is efficient for regularizing structure reconstruction via prior...

  2. Prior knowledge, random walks and human skeletal muscle segmentation.

    Science.gov (United States)

    Baudin, P Y; Azzabou, N; Carlier, P G; Paragios, Nikos

    2012-01-01

    In this paper, we propose a novel approach for segmenting the skeletal muscles in MRI automatically. In order to deal with the absence of contrast between the different muscle classes, we proposed a principled mathematical formulation that integrates prior knowledge with a random walks graph-based formulation. Prior knowledge is represented using a statistical shape atlas that once coupled with the random walks segmentation leads to an efficient iterative linear optimization system. We reveal the potential of our approach on a challenging set of real clinical data.

  3. Cochlea Segmentation using Iterated Random Walks with Shape Prior

    DEFF Research Database (Denmark)

    Ruiz Pujadas, Esmeralda; Kjer, Hans Martin; Vera, Sergio

    2016-01-01

    Cochlear implants can restore hearing to deaf or partially deaf patients. In order to plan the intervention, a model from high resolution μCT images is to be built from accurate cochlea segmentations and then, adapted to a patient-specific model. Thus, a precise segmentation is required to build...... such a model. We propose a new framework for segmentation of μCT cochlear images using random walks where a region term is combined with a distance shape prior weighted by a confidence map to adjust its influence according to the strength of the image contour. Then, the region term can take advantage...

  4. Bayesian Inference for Structured Spike and Slab Priors

    DEFF Research Database (Denmark)

    Andersen, Michael Riis; Winther, Ole; Hansen, Lars Kai

    2014-01-01

    Sparse signal recovery addresses the problem of solving underdetermined linear inverse problems subject to a sparsity constraint. We propose a novel prior formulation, the structured spike and slab prior, which allows to incorporate a priori knowledge of the sparsity pattern by imposing a spatial...... Gaussian process on the spike and slab probabilities. Thus, prior information on the structure of the sparsity pattern can be encoded using generic covariance functions. Furthermore, we provide a Bayesian inference scheme for the proposed model based on the expectation propagation framework. Using...

  5. Random Walk Graph Laplacian-Based Smoothness Prior for Soft Decoding of JPEG Images.

    Science.gov (United States)

    Liu, Xianming; Cheung, Gene; Wu, Xiaolin; Zhao, Debin

    2017-02-01

    Given the prevalence of joint photographic experts group (JPEG) compressed images, optimizing image reconstruction from the compressed format remains an important problem. Instead of simply reconstructing a pixel block from the centers of indexed discrete cosine transform (DCT) coefficient quantization bins (hard decoding), soft decoding reconstructs a block by selecting appropriate coefficient values within the indexed bins with the help of signal priors. The challenge thus lies in how to define suitable priors and apply them effectively. In this paper, we combine three image priors-Laplacian prior for DCT coefficients, sparsity prior, and graph-signal smoothness prior for image patches-to construct an efficient JPEG soft decoding algorithm. Specifically, we first use the Laplacian prior to compute a minimum mean square error initial solution for each code block. Next, we show that while the sparsity prior can reduce block artifacts, limiting the size of the overcomplete dictionary (to lower computation) would lead to poor recovery of high DCT frequencies. To alleviate this problem, we design a new graph-signal smoothness prior (desired signal has mainly low graph frequencies) based on the left eigenvectors of the random walk graph Laplacian matrix (LERaG). Compared with the previous graph-signal smoothness priors, LERaG has desirable image filtering properties with low computation overhead. We demonstrate how LERaG can facilitate recovery of high DCT frequencies of a piecewise smooth signal via an interpretation of low graph frequency components as relaxed solutions to normalized cut in spectral clustering. Finally, we construct a soft decoding algorithm using the three signal priors with appropriate prior weights. Experimental results show that our proposal outperforms the state-of-the-art soft decoding algorithms in both objective and subjective evaluations noticeably.

  6. Short communication: Alteration of priors for random effects in Gaussian linear mixed model

    DEFF Research Database (Denmark)

    Vandenplas, Jérémie; Christensen, Ole Fredslund; Gengler, Nicholas

    2014-01-01

    such alterations. Therefore, the aim of this study was to propose a method to alter both the mean and (co)variance of the prior multivariate normal distributions of random effects of linear mixed models while using currently available software packages. The proposed method was tested on simulated examples with 3......Linear mixed models, for which the prior multivariate normal distributions of random effects are assumed to have a mean equal to 0, are commonly used in animal breeding. However, some statistical analyses (e.g., the consideration of a population under selection into a genomic scheme breeding......, multiple-trait predictions of lactation yields, and Bayesian approaches integrating external information into genetic evaluations) need to alter both the mean and (co)variance of the prior distributions and, to our knowledge, most software packages available in the animal breeding community do not permit...

  7. Bayesian estimation in animal breeding using the Dirichlet process prior for correlated random effects

    Directory of Open Access Journals (Sweden)

    Pretorius Albertus

    2003-03-01

    Full Text Available Abstract In the case of the mixed linear model the random effects are usually assumed to be normally distributed in both the Bayesian and classical frameworks. In this paper, the Dirichlet process prior was used to provide nonparametric Bayesian estimates for correlated random effects. This goal was achieved by providing a Gibbs sampler algorithm that allows these correlated random effects to have a nonparametric prior distribution. A sampling based method is illustrated. This method which is employed by transforming the genetic covariance matrix to an identity matrix so that the random effects are uncorrelated, is an extension of the theory and the results of previous researchers. Also by using Gibbs sampling and data augmentation a simulation procedure was derived for estimating the precision parameter M associated with the Dirichlet process prior. All needed conditional posterior distributions are given. To illustrate the application, data from the Elsenburg Dormer sheep stud were analysed. A total of 3325 weaning weight records from the progeny of 101 sires were used.

  8. Random walks with shape prior for cochlea segmentation in ex vivo μCT

    DEFF Research Database (Denmark)

    Ruiz Pujadas, Esmeralda; Kjer, Hans Martin; Piella, Gemma

    2016-01-01

    previously proposed the use of a high-resolution model built from μCT images and then adapted to patient-specific clinical CT scans. As the accuracy of the model is dependent on the precision of the original segmentation, it is extremely important to have accurate μCT segmentation algorithms. Methods We......(2):236–253, 2013) and constrained random walks (Li et al. in Advances in image and video technology. Springer, Berlin, pp 215–226, 2012). Our approach demonstrated higher accuracy results due to the probability density model constituted by the region term and shape prior information weighed by a confidence map...

  9. Segmentation of cone-beam CT using a hidden Markov random field with informative priors

    Science.gov (United States)

    Moores, M.; Hargrave, C.; Harden, F.; Mengersen, K.

    2014-03-01

    Cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. The rich sources of prior information in IGRT are incorporated into a hidden Markov random field model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk. The voxel labels are estimated using iterated conditional modes. The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom. The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.

  10. Adjunct mifepristone for cervical preparation prior to dilation and evacuation: a randomized trial.

    Science.gov (United States)

    Shaw, Kate A; Shaw, Jonathan G; Hugin, Michele; Velasquez, Griselda; Hopkins, Frederick W; Blumenthal, Paul D

    2015-04-01

    The objective was to investigate mifepristone as a potential adjunct to cervical preparation for surgical abortion after 19 weeks of gestation, with the aim of improving procedure access, convenience and comfort. This is a site-stratified, block-randomized, noninferiority trial of 50 women undergoing surgical abortion between 19 and 23 6/7 weeks of gestation randomized to receive either one set of osmotic dilators plus mifepristone the day prior to procedure (mifepristone group) or two sets of osmotic dilators (placed 18-24 h apart) in the 2 days prior to procedure (control group). All subjects received preprocedure misoprostol. Primary outcome was procedure time. Secondary outcomes included preoperative cervical dilation, ease of procedure, and side effects and pain experienced by subjects. Mean gestational age was similar between groups (20 weeks); more nulliparous subjects were randomized to the mifepristone group (46% vs. 12%, p=.009). Mean procedure times were similar: mifepristone group 11:52 (SD 5:29) vs. control group 10:56 (SD 5:08); difference in means -56s, with confidence interval (95% CI -4:09 to +2:16) not exceeding the 5-min difference we a priori defined as clinically significant. Preprocedure cervical dilation did not differ and was >3cm for the majority of subjects in both groups. There was no difference (p=.6) in ease of procedure reported by providers. Preoperative (postmisoprostol) pain and postoperative pain levels were greater with mifepristone (p = 0.02 and p= 0.04 respectively). Overall subject experience was not different (p=0.80), with most reporting a "better than expected" experience. Mifepristone with one set of osmotic dilators and misoprostol did not result in longer procedure times or less cervical dilation than serial (two sets) of osmotic dilators and misoprostol, and has the potential to improve access to second trimester abortion without compromising safety. Use of mifepristone for cervical preparation before surgical abortion

  11. Automated segmentation of dental CBCT image with prior-guided sequential random forests

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li; Gao, Yaozong; Shi, Feng; Li, Gang [Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7513 (United States); Chen, Ken-Chung; Tang, Zhen [Surgical Planning Laboratory, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, Texas 77030 (United States); Xia, James J., E-mail: dgshen@med.unc.edu, E-mail: JXia@HoustonMethodist.org [Surgical Planning Laboratory, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, Texas 77030 (United States); Department of Surgery (Oral and Maxillofacial Surgery), Weill Medical College, Cornell University, New York, New York 10065 (United States); Department of Oral and Craniomaxillofacial Surgery, Shanghai Jiao Tong University School of Medicine, Shanghai Ninth People’s Hospital, Shanghai 200011 (China); Shen, Dinggang, E-mail: dgshen@med.unc.edu, E-mail: JXia@HoustonMethodist.org [Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7513 and Department of Brain and Cognitive Engineering, Korea University, Seoul 02841 (Korea, Republic of)

    2016-01-15

    Purpose: Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate 3D models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the image artifacts caused by beam hardening, imaging noise, inhomogeneity, truncation, and maximal intercuspation, it is difficult to segment the CBCT. Methods: In this paper, the authors present a new automatic segmentation method to address these problems. Specifically, the authors first employ a majority voting method to estimate the initial segmentation probability maps of both mandible and maxilla based on multiple aligned expert-segmented CBCT images. These probability maps provide an important prior guidance for CBCT segmentation. The authors then extract both the appearance features from CBCTs and the context features from the initial probability maps to train the first-layer of random forest classifier that can select discriminative features for segmentation. Based on the first-layer of trained classifier, the probability maps are updated, which will be employed to further train the next layer of random forest classifier. By iteratively training the subsequent random forest classifier using both the original CBCT features and the updated segmentation probability maps, a sequence of classifiers can be derived for accurate segmentation of CBCT images. Results: Segmentation results on CBCTs of 30 subjects were both quantitatively and qualitatively validated based on manually labeled ground truth. The average Dice ratios of mandible and maxilla by the authors’ method were 0.94 and 0.91, respectively, which are significantly better than the state-of-the-art method based on sparse representation (p-value < 0.001). Conclusions: The authors have developed and validated a novel fully automated method

  12. Monocular Road Detection Using Structured Random Forest

    Directory of Open Access Journals (Sweden)

    Liang Xiao

    2016-05-01

    Full Text Available Road detection is a key task for autonomous land vehicles. Monocular vision-based road-detection algorithms are mostly based on machine learning approaches and are usually cast as classification problems. However, the pixel-wise classifiers are faced with the ambiguity caused by changes in road appearance, illumination and weather. An effective way to reduce the ambiguity is to model the contextual information with structured learning and prediction. Currently, the widely used structured prediction model in road detection is the Markov random field or conditional random field. However, the random field-based methods require additional complex optimization after pixel-wise classification, making them unsuitable for real-time applications. In this paper, we present a structured random forest-based road-detection algorithm which is capable of modelling the contextual information efficiently. By mapping the structured label space to a discrete label space, the test function of each split node can be trained in a similar way to that of the classical random forests. Structured random forests make use of the contextual information of image patches as well as the structural information of the labels to get more consistent results. Besides this benefit, by predicting a batch of pixels in a single classification, the structured random forest-based road detection can be much more efficient than the conventional pixel-wise random forest. Experimental results tested on the KITTI-ROAD dataset and data collected in typical unstructured environments show that structured random forest-based road detection outperforms the classical pixel-wise random forest both in accuracy and efficiency.

  13. Effects of prior knowledge and concept-map structure on disorientation, cognitive load, and learning

    NARCIS (Netherlands)

    Amadieu, Franck; Van Gog, Tamara; Paas, Fred; Tricot, André; Mariné, Claudette

    2009-01-01

    Citation: Amadieu, F., Van Gog, T., Paas, F., Tricot, A., & Mariné, C. (2009). Effects of prior knowledge and concept-map structure on disorientation, cognitive load, and learning. Learning and Instruction, 19, 376-386.

  14. Weight reduction intervention for obese infertile women prior to IVF: a randomized controlled trial.

    Science.gov (United States)

    Einarsson, Snorri; Bergh, Christina; Friberg, Britt; Pinborg, Anja; Klajnbard, Anna; Karlström, Per-Olof; Kluge, Linda; Larsson, Ingrid; Loft, Anne; Mikkelsen-Englund, Anne-Lis; Stenlöf, Kaj; Wistrand, Anna; Thurin-Kjellberg, Ann

    2017-08-01

    Does an intensive weight reduction programme prior to IVF increase live birth rates for infertile obese women? An intensive weight reduction programme resulted in a large weight loss but did not substantially affect live birth rates in obese women scheduled for IVF. Among obese women, fertility and obstetric outcomes are influenced negatively with increased risk of miscarriage and a higher risk of maternal and neonatal complications. A recent large randomized controlled trial found no effect of lifestyle intervention on live birth in infertile obese women. A prospective, multicentre, randomized controlled trial was performed between 2010 and 2016 in the Nordic countries. In total, 962 women were assessed for eligibility and 317 women were randomized. Computerized randomization with concealed allocation was performed in the proportions 1:1 to one of two groups: weight reduction intervention followed by IVF-treatment or IVF-treatment only. One cycle per patient was included. Nine infertility clinics in Sweden, Denmark and Iceland participated. Women under 38 years of age planning IVF, and having a BMI ≥30 and IVF, starting with 12 weeks of a low calorie liquid formula diet (LCD) of 880 kcal/day and thereafter weight stabilization for 2-5 weeks, or a control group (157 patients) with IVF only. In the full analysis set (FAS), the live birth rate was 29.6% (45/152) in the weight reduction and IVF group and 27.5% (42/153) in the IVF only group. The difference was not statistically significant (difference 2.2%, 95% CI: 12.9 to -8.6, P = 0.77). The mean weight change was -9.44 (6.57) kg in the weight reduction and IVF group as compared to +1.19 (1.95) kg in the IVF only group, being highly significant (P IVF group, 10.5% (16) as compared to the IVF only group 2.6% (4) (P = 0.009). Miscarriage rates and gonadotropin dose used for IVF stimulation did not differ between groups. Two subgroup analyses were performed. The first compared women with PCOS in the two randomized

  15. Effects of Prior Knowledge and Concept-Map Structure on Disorientation, Cognitive Load, and Learning

    Science.gov (United States)

    Amadieu, Franck; van Gog, Tamara; Paas, Fred; Tricot, Andre; Marine, Claudette

    2009-01-01

    This study explored the effects of prior knowledge (high vs. low; HPK and LPK) and concept-map structure (hierarchical vs. network; HS and NS) on disorientation, cognitive load, and learning from non-linear documents on "the infection process of a retrograde virus (HIV)". Participants in the study were 24 adults. Overall subjective ratings of…

  16. The effect of parenteral testosterone administration prior to hypospadias surgery: A prospective, randomized and controlled study.

    Science.gov (United States)

    Asgari, S A; Safarinejad, M R; Poorreza, F; Asl, A Safaei; Ghanaie, M Mansour; Shahab, E

    2015-06-01

    The goal of hypospadias surgery is to provide a functionally and cosmetically normal penis. Whether this goal will be to the patient's satisfaction depends largely on the original anatomy, surgical technique and surgeon's experience. It has been suggested that androgen administration is associated with better outcomes in hypospadias repair; however, few studies have included control groups and the issue is still controversial. To evaluate the effects of parenteral testosterone administration on the results of hypospadias repair in children with untreated hypospadias. A total of 182 children with midshaft or distal hypospadias and a mean age of 30 months (range 18-52 months) were enrolled in this study. Consecutive children were randomly allocated to the study group (testosterone administration) (Group 1, n = 91) or control group (Group 2, n = 91). Only children with a flat urethral plate were included in this study. The control group did not receive any pre-operative treatment. Children with a previous history of hypospadias repair and any proven endocrine disorder were excluded. The study children received 2 mg/kg testosterone enanthate monthly for two months before surgery. Tubularized incised plate (TIP) urethroplasty, with or without chordee correction, was performed for all children in both groups by the same urologist. Hypospadias repair was performed 4 weeks after the second dose of testosterone administration. Postoperative complications were recorded, including: urethrocutaneous fistulas, urethral diverticula, meatal stenosis, and glanular dehiscence. The mean stretched penile length and circumference were measured at baseline and at 1 month and 2 months post operation. All children were examined every month for any adverse affects to testosterone treatment, like pubic and axillary hair, and height acceleration, up to 3 months post operation. An increase in penile length (from 28.1 ± 2.2 mm to 38.5 ± 2.6 mm) (P = 0.001) and penile circumference (from 35

  17. Random Start Ovarian Stimulation for Oocyte or Embryo Cryopreservation in Women Desiring Fertility Preservation Prior to Gonadotoxic Cancer Therapy.

    Science.gov (United States)

    Danis, Rachel B; Pereira, Nigel; Elias, Rony T

    2017-11-10

    Women of reproductive age diagnosed with cancer are often interested in preserving gametes or reproductive tissue that would allow for future genetic parenthood. Preservation of fertility is often accomplished in young cancer patients via ovarian stimulation followed by oocyte or embryo cryopreservation. Conventional stimulation protocols, however, require 2-4 weeks to complete ovarian stimulation, oocyte retrieval and possible fertilization. Such a strategy may not be feasible in patients requiring urgent cancer treatment. Recent studies have highlighted that random start ovarian stimulation can be initiated irrespective of the phase of the menstrual cycle and is an attractive alternative to conventional ovarian stimulation. The primary aim of the current review is to discuss the feasibility and success of random start ovarian stimulation for oocyte or embryo cryopreservation in women desiring fertility preservation prior to gonadotoxic cancer therapy. We performed a systematic review of medical literature published between January 2000 to June 2017 reporting the utility of random start ovarian stimulation for fertility preservation. Search terms included "fertility preservation," "cancer," "ovarian stimulation," "random-start ovarian stimulation," "embryo cryopreservation, and" "oocyte cryopreservation." Publications were included in this review only if patients underwent random start ovarian stimulation prior to cancer therapy. Nineteen publications were identified and perused by the authors. Most publications described the utility of random start ovarian stimulation in the setting of breast cancer. Radom-start stimulation was associated with a reduced time interval between ovarian stimulation initiation and oocyte or embryo cryopreservation. The yield of mature oocytes and their developmental potential into embryos was comparable between conventional and random-start protocols, albeit with higher gonadotropin doses in the latter. The current review suggests

  18. Acupuncture decreases competitive anxiety prior to a competition in young athletes: a randomized controlled trial pilot study.

    Science.gov (United States)

    Zarei, Sahar; Shayestehfar, Monir; Memari, Amir-Hossein; SeifBarghi, Tohid; Sobhani, Vahid

    2017-03-01

    Background Although a certain level of competitive anxiety may increase performance, many athletes with anxiety experience uncontrolled negative feelings and cognition that in turn can have overwhelming effects on their performance. Methods We aimed to assess the effect of acupuncture on competitive anxiety of the adolescent football players prior to the competition using psychological and physiological markers. A total of 30 athletes were randomly and equally allocated to either acupuncture or sham control group. Results The results of t-test on posttest scores showed that acupuncture had a significant effect on cognitive anxiety (p=0.001) and somatic anxiety (p0.05). Furthermore, the results showed that acupuncture significantly decreased the skin conductance in acupuncture group compared to sham group (p=0.006) (pacupuncture has the capacity to decrease cognitive and somatic anxiety prior to competition in adolescent athletes while this was accompanied by significant physiological changes.

  19. Aspects of randomness in neural graph structures

    CERN Document Server

    Rudolph-Lilith, Michelle

    2013-01-01

    In the past two decades, significant advances have been made in understanding the structural and functional properties of biological networks, via graph-theoretic analysis. In general, most graph-theoretic studies are conducted in the presence of serious uncertainties, such as major undersampling of the experimental data. In the specific case of neural systems, however, a few moderately robust experimental reconstructions do exist, and these have long served as fundamental prototypes for studying connectivity patterns in the nervous system. In this paper, we provide a comparative analysis of these "historical" graphs, both in (unmodified) directed and (often symmetrized) undirected forms, and focus on simple structural characterizations of their connectivity. We find that in most measures the networks studied are captured by simple random graph models; in a few key measures, however, we observe a marked departure from the random graph prediction. Our results suggest that the mechanism of graph formation in th...

  20. Premedication with midazolam prior to cesarean delivery in preeclamptic parturients: A randomized controlled trial.

    Science.gov (United States)

    Mokhtar, Ali M; Elsakka, Ahmed I; Ali, Hassan M

    2016-01-01

    Anxiety is a concern in obstetrics, especially in preeclamptic mothers. Sedation is not commonly used in parturients for fear of adverse neonatal effect. We investigated maternal and neonatal outcome of midazolam as an adjuvant to spinal anesthesia for elective cesarean delivery. A prospective randomized controlled trial, in which eighty preeclamptic parturients received either an intravenous dose of 0.035 mg/kg of midazolam or an equal volume of normal saline, 30 min before spinal anesthesia. Maternal anxiety was assessed using Amsterdam Preoperative Anxiety and Information Scale (APAIS); postoperative maternal satisfaction was assessed using Maternal Satisfaction Scale for Cesarean Section (MSSCS). Newborns were assessed using Apgar score, Neonatal Neurologic and Adaptive Capacity Score (NACS), and umbilical artery blood gases. Mothers premedicated with midazolam showed a lower level of preoperative anxiety and a higher degree of postoperative satisfaction than the control group. There were no between-group differences regarding the neonatal outcome. Preeclamptic parturients premedicated with midazolam (0.035 mg/kg) before spinal anesthesia have lower anxiety and higher postoperative satisfaction levels, with no adverse effects on the newborns.

  1. Fatigue in Steel Structures under Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning

    1999-01-01

    Fatigue damage accumulation in steel structures under random loading is studied. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part of the investigation, fatigue test series have been carried through on various...... types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel with a yield stress of ~ 360-410 MPa or high-strength steel with a yield stress of ~ 810-1010 MPa. The fatigue tests and the fracture mechanics analyses...... test results. Both the fracture mechanics analysis and the fatigue test results indicate that Miner's rule, which is normally used in the design against fatigue in steel structures, may give results, which are unconservative, and that the validity of the results obtained from Miner's rule will depend...

  2. Homogeneous 1-based structures and interpretability in random structures

    OpenAIRE

    Koponen, Vera

    2014-01-01

    Let $V$ be a finite relational vocabulary in which no symbol has arity greater than 2. Let $M$ be countable $V$-structure which is homogeneous, simple and 1-based. The first main result says that if $M$ is, in addition, primitive, then it is strongly interpretable in a random structure. The second main result, which generalizes the first, implies (without the assumption on primitivity) that if $M$ is "coordinatized" by a set with SU-rank 1 and there is no definable (without parameters) nontri...

  3. Analgesic Efficacy of Intrarectal Instillation of Lidocaine Gel prior to Transrectal Ultrasound Guided Prostate Biopsy: A Prospective Randomized Trial

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Tae Jin; Kim, Seung Hyup; Cho, Jeong Yeon [Seoul National University Hospital, Seoul (Korea, Republic of); Lee, Hak Jong; Lee, Sang Eun; Byun, Seok Soo [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Seong, Chang Kyu [Seoul National University Borame Hospital, Seoul (Korea, Republic of)

    2006-06-15

    To assess the analgesic efficacy of intrarectal lidocaine gel instillation prior to periprostatic nerve block during transrectal, ultrasound-guided prostate biopsies. Between March 2004 and October 2004, 203 consecutive patients for prostate biopsies were randomized into two groups. In 90 patients of group A, 10ml of 2% lidocaine gel was instilled intrarectally 10 minutes prior to periprostatic neurovascular bundle block, while 113 patients of group B received only periprostatic neurovascular bundle block without lidocaine gel instillation. Pain was assessed with the visual analogue pain scale, during periprostatic neurovascular bundle block (VAS 1), during the biopsy procedures (VAS 2) and 20 minutes after the procedure (VAS 3). The difference in VAS scores between patients in the two groups was evaluated with the unpaired t-test, with p < 0.05 considered significant. Patients in group A experienced statistically less pain during transrectal ultrasound guided prostate biopsy (VAS 2, 2.994 versus 3.903, p < 0.01). However, no significant difference in VAS values could be demonstrated during periprostatic neurovascular bundle block (VAS 1, 4.761 versus 5.133, p > 0.05) or at after 20 minutes after the procedure (VAS 3, 0.9778 versus 1.257, p > 0.05). Intrarectal instillation of lidocaine gel leads to significant additional analgesic efficacy during the biopsy procedure. It is a simple, safe and rapid technique that should be considered in all patients undergoing TRUS guided prostate biopsy

  4. Polynomial Chaos Acceleration for the Bayesian Inference of Random Fields with Gaussian Priors and Uncertain Covariance Hyper-Parameters

    KAUST Repository

    Le Maitre, Olivier

    2015-01-07

    We address model dimensionality reduction in the Bayesian inference of Gaussian fields, considering prior covariance function with unknown hyper-parameters. The Karhunen-Loeve (KL) expansion of a prior Gaussian process is traditionally derived assuming fixed covariance function with pre-assigned hyperparameter values. Thus, the modes strengths of the Karhunen-Loeve expansion inferred using available observations, as well as the resulting inferred process, dependent on the pre-assigned values for the covariance hyper-parameters. Here, we seek to infer the process and its the covariance hyper-parameters in a single Bayesian inference. To this end, the uncertainty in the hyper-parameters is treated by means of a coordinate transformation, leading to a KL-type expansion on a fixed reference basis of spatial modes, but with random coordinates conditioned on the hyper-parameters. A Polynomial Chaos (PC) expansion of the model prediction is also introduced to accelerate the Bayesian inference and the sampling of the posterior distribution with MCMC method. The PC expansion of the model prediction also rely on a coordinates transformation, enabling us to avoid expanding the dependence of the prediction with respect to the covariance hyper-parameters. We demonstrate the efficiency of the proposed method on a transient diffusion equation by inferring spatially-varying log-diffusivity fields from noisy data.

  5. Harnessing data structure for recovery of randomly missing structural vibration responses time history: Sparse representation versus low-rank structure

    Science.gov (United States)

    Yang, Yongchao; Nagarajaiah, Satish

    2016-06-01

    Randomly missing data of structural vibration responses time history often occurs in structural dynamics and health monitoring. For example, structural vibration responses are often corrupted by outliers or erroneous measurements due to sensor malfunction; in wireless sensing platforms, data loss during wireless communication is a common issue. Besides, to alleviate the wireless data sampling or communication burden, certain accounts of data are often discarded during sampling or before transmission. In these and other applications, recovery of the randomly missing structural vibration responses from the available, incomplete data, is essential for system identification and structural health monitoring; it is an ill-posed inverse problem, however. This paper explicitly harnesses the data structure itself-of the structural vibration responses-to address this (inverse) problem. What is relevant is an empirical, but often practically true, observation, that is, typically there are only few modes active in the structural vibration responses; hence a sparse representation (in frequency domain) of the single-channel data vector, or, a low-rank structure (by singular value decomposition) of the multi-channel data matrix. Exploiting such prior knowledge of data structure (intra-channel sparse or inter-channel low-rank), the new theories of ℓ1-minimization sparse recovery and nuclear-norm-minimization low-rank matrix completion enable recovery of the randomly missing or corrupted structural vibration response data. The performance of these two alternatives, in terms of recovery accuracy and computational time under different data missing rates, is investigated on a few structural vibration response data sets-the seismic responses of the super high-rise Canton Tower and the structural health monitoring accelerations of a real large-scale cable-stayed bridge. Encouraging results are obtained and the applicability and limitation of the presented methods are discussed.

  6. Non-stationary random vibration analysis of structures under multiple correlated normal random excitations

    Science.gov (United States)

    Li, Yanbin; Mulani, Sameer B.; Kapania, Rakesh K.; Fei, Qingguo; Wu, Shaoqing

    2017-07-01

    An algorithm that integrates Karhunen-Loeve expansion (KLE) and the finite element method (FEM) is proposed to perform non-stationary random vibration analysis of structures under excitations, represented by multiple random processes that are correlated in both time and spatial domains. In KLE, the auto-covariance functions of random excitations are discretized using orthogonal basis functions. The KLE for multiple correlated random excitations relies on expansions in terms of correlated sets of random variables reflecting the cross-covariance of the random processes. During the response calculations, the eigenfunctions of KLE used to represent excitations are applied as forcing functions to the structure. The proposed algorithm is applied to a 2DOF system, a 2D cantilever beam and a 3D aircraft wing under both stationary and non-stationary correlated random excitations. Two methods are adopted to obtain the structural responses: a) the modal method and b) the direct method. Both the methods provide the statistics of the dynamic response with sufficient accuracy. The structural responses under the same type of correlated random excitations are bounded by the response obtained by perfectly correlated and uncorrelated random excitations. The structural response increases with a decrease in the correlation length and with an increase in the correlation magnitude. The proposed methodology can be applied for the analysis of any complex structure under any type of random excitation.

  7. Nonlinear deterministic structures and the randomness of protein sequences

    CERN Document Server

    Huang Yan Zhao

    2003-01-01

    To clarify the randomness of protein sequences, we make a detailed analysis of a set of typical protein sequences representing each structural classes by using nonlinear prediction method. No deterministic structures are found in these protein sequences and this implies that they behave as random sequences. We also give an explanation to the controversial results obtained in previous investigations.

  8. a Climatology of Synoptic Scale Atmospheric Structure Prior to Severe Convective Storms

    Science.gov (United States)

    Taylor, Gregory Eugene

    1982-03-01

    This investigation determines those unique properties of the thermodynamic and kinematic structure of the atmosphere in the region where tornado bearing thunderstorms develop as compared to surrounding locations. One hundred five upper air soundings from the operational rawinsonde network, hereafter called tornado proximity soundings, comprise the core of the data base. In each instance, a confirmed tornado occurred within 50 statute miles of and within 105 minutes after the release of the radiosonde. In earlier research of this nature, the thermodynamic and kinematic properties of the atmosphere in the region of tornado bearing thunderstorm development were interpolated or inferred from upper air soundings made at locations surrounding the severe storm location. These surrounding locations, however, were characterized by at most non-tornado bearing thunderstorm development. In this investigation, however, measurements of the atmospheric structure near in space and time to the subsequent tornado bearing thunderstorm development have been utilized. This fact should enhance the probability of detecting the presumably unique properties of the atmospheric structure prior to severe storm development as compared to previous investigations. Height, temperature, mixing ratio, and U and V wind component data from the tornado proximity sounding station and surrounding upper air stations were objectively analyzed to a regularly spaced three dimensional grid network centered on the tornado proximity sounding station. From the basic data, a large number of derived variables which had been previously linked to severe storms were computed. Each case was categorized into one of six different classifications based on the geographical location and date of the tornado proximity sounding. The results from the six categories indicate that the most pronounced unique properties of the pre-severe storm environment are within the lower levels of the atmosphere. In particular, the low level

  9. Solution Methods for Structures with Random Properties Subject to Random Excitation

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Nielsen, Søren R. K.; Cakmak, A. S.

    This paper deals with the lower order statistical moments of the response of structures with random stiffness and random damping properties subject to random excitation. The arising stochastic differential equations (SDE) with random coefficients are solved by two methods, a second order...... perturbation approach and a Markovian method. The second order perturbation approach is grounded on the total probability theorem and can be compactly written. Moreover, the problem to be solved is independent of the dimension of the random variables involved. The Markovian approach suggests transforming...... the SDE with random coefficients with deterministic initial conditions to an equivalent nonlinear SDE with deterministic coefficient and random initial conditions. In both methods, the statistical moment equations are used. Hierarchy of statistical moments in the markovian approach is closed...

  10. Geometry, structure and randomness in combinatorics

    CERN Document Server

    Nešetřil, Jaroslav; Pellegrini, Marco

    2014-01-01

    This book collects some surveys on current trends in discrete mathematics and discrete geometry. The areas covered include:  graph representations, structural graphs theory, extremal graph theory, Ramsey theory and constrained satisfaction problems.

  11. Enhancing k-space quantitative susceptibility mapping by enforcing consistency on the cone data (CCD) with structural priors.

    Science.gov (United States)

    Wen, Yan; Wang, Yi; Liu, Tian

    2016-02-01

    The inversion from the magnetic field to the magnetic susceptibility distribution is ill-posed because the dipole kernel, which relates the magnetic susceptibility to the magnetic field, has zeroes at a pair of cone surfaces in the k-space, leading to streaking artifacts on the reconstructed quantitative susceptibility maps (QSM). A method to impose consistency on the cone data (CCD) with structural priors is proposed to improve the solutions of k-space methods. The information in the cone region is recovered by enforcing structural consistency with structural prior, while information in the noncone trust region is enforced to be consistent with the magnetic field measurements in k-space. This CCD method was evaluated by comparing the initial results of existing QSM algorithms to the QSM results after CCD enhancement with respect to the COSMOS results in simulation, phantom, and in vivo human brain. The proposed method demonstrated suppression of streaking artifacts and the resulting QSM showed better agreement with reference standard QSM compared with other k-space based methods. By enforcing consistency with structural priors in the cone region, the missing data in the cone can be recovered and the streaking artifacts in QSM can be suppressed. © 2015 Wiley Periodicals, Inc.

  12. Color effects from scattering on random surface structures in dielectrics

    DEFF Research Database (Denmark)

    Clausen, Jeppe; Christiansen, Alexander B; Garnæs, Jørgen

    2012-01-01

    We show that cheap large area color filters, based on surface scattering, can be fabricated in dielectric materials by replication of random structures in silicon. The specular transmittance of three different types of structures, corresponding to three different colors, have been characterized...

  13. Random generation of RNA secondary structures according to native distributions

    Directory of Open Access Journals (Sweden)

    Nebel Markus E

    2011-10-01

    Full Text Available Abstract Background Random biological sequences are a topic of great interest in genome analysis since, according to a powerful paradigm, they represent the background noise from which the actual biological information must differentiate. Accordingly, the generation of random sequences has been investigated for a long time. Similarly, random object of a more complicated structure like RNA molecules or proteins are of interest. Results In this article, we present a new general framework for deriving algorithms for the non-uniform random generation of combinatorial objects according to the encoding and probability distribution implied by a stochastic context-free grammar. Briefly, the framework extends on the well-known recursive method for (uniform random generation and uses the popular framework of admissible specifications of combinatorial classes, introducing weighted combinatorial classes to allow for the non-uniform generation by means of unranking. This framework is used to derive an algorithm for the generation of RNA secondary structures of a given fixed size. We address the random generation of these structures according to a realistic distribution obtained from real-life data by using a very detailed context-free grammar (that models the class of RNA secondary structures by distinguishing between all known motifs in RNA structure. Compared to well-known sampling approaches used in several structure prediction tools (such as SFold ours has two major advantages: Firstly, after a preprocessing step in time O(n2 for the computation of all weighted class sizes needed, with our approach a set of m random secondary structures of a given structure size n can be computed in worst-case time complexity Om⋅n⋅ log(n while other algorithms typically have a runtime in O(m⋅n2. Secondly, our approach works with integer arithmetic only which is faster and saves us from all the discomforting details of using floating point arithmetic with

  14. The effect of the prior flow velocity on the structural organization of aggregated erythrocytes in the quiescent blood.

    Science.gov (United States)

    Pribush, Alexander; Meyerstein, Dan; Meyerstein, Naomi

    2011-02-01

    Usually, investigations of erythrocyte aggregation at rest are focused on effects of the strength of erythrocyte-erythrocyte attractive interactions and the volume fraction of the cells, whereas the role of prior flow velocity has not been thoroughly investigated. The aim of this study is to fill this gap. The main conclusions extracted from time records of the complex admittance of blood are as follows: (1) Dispersion of blood in a prior flow into discrete aggregates increases the mesh size of network, which, as has been recently shown, is formed in the quiescent blood. (2) If the energy of the flow field is sufficient to prevent the formation of face-to-side intercellular links, so that the dispersed phase consists of linear rouleaux, changes in the mesh size correlate positively with the length of rouleaux. (3) At slower prior flow velocities, the cells are combined into branched aggregates. As the degree of branching increases, the effect becomes less important. (4) The effects of the length of linear rouleaux and the degree of branching of ramified aggregates on the mesh size are qualitatively similar for suspensions with different aggregating media. (5) Erythrocytes suspended in strongly aggregating media form at low flow conditions a network-like structure. In this case, unlike high and moderate prior flow regimes, the mesh size of RBC network at rest is less than that formed after the stoppage of completely dispersed blood. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Stenting or not prior to extracorporeal shockwave lithotripsy for ureteral stones? Results of a prospective randomized study.

    Science.gov (United States)

    Sfoungaristos, Stavros; Polimeros, Nikolaos; Kavouras, Adamantios; Perimenis, Petros

    2012-06-01

    To determine the need for pre-treatment stenting in patients undergoing extracorporeal shockwave lithotripsy (ESWL) for ureteral stones sized 4-10 mm. A prospective randomized study was conducted between September 2009 and March 2011. Included 156 patients randomized in stented and non-stented groups and underwent a maximum of 3 ESWL sessions. Radiographic follow-up was used to assess the stone fragmentation and clearance. Results were compared in terms of stone-free rates, post-treatment morbidity and complications. Overall efficacy was 76.9%. Stone-free rates were statistically significantly lower (P = 0.026) in the stented group (68.6%) compared to the non-stented ones (83.7%). Furthermore, stenting was significantly correlated with post-treatment lower urinary tract symptoms (P ≤ 0.001), need for more ESWL sessions (P = 0.019) and possibility for operation due to ESWL failure (P = 0.026). A multivariate analysis was conducted to identify the parameters which may predict complete stone removal after ESWL. Stone size (P = 0.026), stone location (P = 0.011) and stenting (P = 0.007) were the most significant factors. ESWL is an efficient and safe treatment for 4- to 10-mm ureteral stones. Pre-treatment stenting is limiting stone-free rates and is significantly influencing post-ESWL morbidity and quality of life in a negative manner, while it contributes minimally to the prophylaxis of complications.

  16. Asymptotic structural properties of quasi-random saturated structures of RNA

    Science.gov (United States)

    2013-01-01

    Background RNA folding depends on the distribution of kinetic traps in the landscape of all secondary structures. Kinetic traps in the Nussinov energy model are precisely those secondary structures that are saturated, meaning that no base pair can be added without introducing either a pseudoknot or base triple. In previous work, we investigated asymptotic combinatorics of both random saturated structures and of quasi-random saturated structures, where the latter are constructed by a natural stochastic process. Results We prove that for quasi-random saturated structures with the uniform distribution, the asymptotic expected number of external loops is O(logn) and the asymptotic expected maximum stem length is O(logn), while under the Zipf distribution, the asymptotic expected number of external loops is O(log2n) and the asymptotic expected maximum stem length is O(logn/log logn). Conclusions Quasi-random saturated structures are generated by a stochastic greedy method, which is simple to implement. Structural features of random saturated structures appear to resemble those of quasi-random saturated structures, and the latter appear to constitute a class for which both the generation of sampled structures as well as a combinatorial investigation of structural features may be simpler to undertake. PMID:24156624

  17. Graphene materials having randomly distributed two-dimensional structural defects

    Science.gov (United States)

    Kung, Harold H; Zhao, Xin; Hayner, Cary M; Kung, Mayfair C

    2013-10-08

    Graphene-based storage materials for high-power battery applications are provided. The storage materials are composed of vertical stacks of graphene sheets and have reduced resistance for Li ion transport. This reduced resistance is achieved by incorporating a random distribution of structural defects into the stacked graphene sheets, whereby the structural defects facilitate the diffusion of Li ions into the interior of the storage materials.

  18. Random walk models of large-scale structure

    Indian Academy of Sciences (India)

    Abstract. This paper describes the insights gained from the excursion set approach, in which vari- ous questions about the phenomenology of large-scale structure formation can be mapped to problems associated with the first crossing distribution of appropriately defined barriers by random walks. Much of this is ...

  19. Random Effects Structure for Confirmatory Hypothesis Testing: Keep It Maximal

    Science.gov (United States)

    Barr, Dale J.; Levy, Roger; Scheepers, Christoph; Tily, Harry J.

    2013-01-01

    Linear mixed-effects models (LMEMs) have become increasingly prominent in psycholinguistics and related areas. However, many researchers do not seem to appreciate how random effects structures affect the generalizability of an analysis. Here, we argue that researchers using LMEMs for confirmatory hypothesis testing should minimally adhere to the…

  20. Exploring community structure in biological networks with random graphs.

    Science.gov (United States)

    Sah, Pratha; Singh, Lisa O; Clauset, Aaron; Bansal, Shweta

    2014-06-25

    Community structure is ubiquitous in biological networks. There has been an increased interest in unraveling the community structure of biological systems as it may provide important insights into a system's functional components and the impact of local structures on dynamics at a global scale. Choosing an appropriate community detection algorithm to identify the community structure in an empirical network can be difficult, however, as the many algorithms available are based on a variety of cost functions and are difficult to validate. Even when community structure is identified in an empirical system, disentangling the effect of community structure from other network properties such as clustering coefficient and assortativity can be a challenge. Here, we develop a generative model to produce undirected, simple, connected graphs with a specified degrees and pattern of communities, while maintaining a graph structure that is as random as possible. Additionally, we demonstrate two important applications of our model: (a) to generate networks that can be used to benchmark existing and new algorithms for detecting communities in biological networks; and (b) to generate null models to serve as random controls when investigating the impact of complex network features beyond the byproduct of degree and modularity in empirical biological networks. Our model allows for the systematic study of the presence of community structure and its impact on network function and dynamics. This process is a crucial step in unraveling the functional consequences of the structural properties of biological systems and uncovering the mechanisms that drive these systems.

  1. Different Routes of Misoprostol for Same-Day Cervical Priming Prior to Operative Hysteroscopy: A Randomized Blinded Trial.

    Science.gov (United States)

    Ganer Herman, Hadas; Kerner, Ram; Gluck, Ohad; Feit, Hagit; Keidar, Ran; Bar, Jacob; Sagiv, Ron

    To compare the effectiveness of and patient satisfaction with different routes of misoprostol administration for short-term cervical priming before operative hysteroscopy. Randomized blinded trial (Canadian Task Force classification I). University hospital. One hundred and twenty patients undergoing operative hysteroscopy. Patients were randomly assigned to receive 400 μg of misoprostol administered orally (n = 40), vaginally (n = 40), or sublingually (n = 40) for cervical priming at 1.5 to 4 hours before undergoing operative hysteroscopy. The primary outcome was preoperative cervical dilatation. Secondary outcomes included cervical consistency, ease of dilation and time of dilation, patient discomfort, and side effects. No differences were noted among the 3 groups in terms of patient age, parity, previous vaginal delivery, menopausal status, and time interval from preparation to procedure. Patients in the 3 groups reported similar discomfort and side effects. Initial mean cervical dilatation was 6.1 ± 2.0 mm in the oral group, 6.4 ± 2.1 in the vaginal group, and 6.4 ± 1.8 mm in the sublingual group (p = .75). Cervical consistency and ease of dilation were similar among the groups. The mean time of dilation was 37.2 ± 30.6 seconds in the oral group, 31.7 ± 29.0 seconds in the vaginal group, and 31.5 ± 21.7 seconds in the sublingual group (p = .59). Additional subanalyses according to menopausal status and parity did not demonstrate any differences among the groups. Same-day cervical priming for operative hysteroscopy is achieved equally with all routes of misoprostol administration, with similar patient satisfaction and side effects. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

  2. Calcium Isotopic Evidence for Vulnerable Marine Ecosystem Structure Prior to the K/Pg Extinction.

    Science.gov (United States)

    Martin, Jeremy E; Vincent, Peggy; Tacail, Théo; Khaldoune, Fatima; Jourani, Essaid; Bardet, Nathalie; Balter, Vincent

    2017-06-05

    The collapse of marine ecosystems during the end-Cretaceous mass extinction involved the base of the food chain [1] up to ubiquitous vertebrate apex predators [2-5]. Large marine reptiles became suddenly extinct at the Cretaceous-Paleogene (K/Pg) boundary, whereas other contemporaneous groups such as bothremydid turtles or dyrosaurid crocodylomorphs, although affected at the familial, genus, or species level, survived into post-crisis environments of the Paleocene [5-9] and could have found refuge in freshwater habitats [10-12]. A recent hypothesis proposes that the extinction of plesiosaurians and mosasaurids could have been caused by an important drop in sea level [13]. Mosasaurids are unusually diverse and locally abundant in the Maastrichtian phosphatic deposits of Morocco, and with large sharks and one species of elasmosaurid plesiosaurian recognized so far, contribute to an overabundance of apex predators [3, 7, 14, 15]. For this reason, high local diversity of marine reptiles exhibiting different body masses and a wealth of tooth morphologies hints at complex trophic interactions within this latest Cretaceous marine ecosystem. Using calcium isotopes, we investigated the trophic structure of this extinct assemblage. Our results are consistent with a calcium isotope pattern observed in modern marine ecosystems and show that plesiosaurians and mosasaurids indiscriminately fall in the tertiary piscivore group. This suggests that marine reptile apex predators relied onto a single dietary calcium source, compatible with the vulnerable wasp-waist food webs of the modern world [16]. This inferred peculiar ecosystem structure may help explain plesiosaurian and mosasaurid extinction following the end-Cretaceous biological crisis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Multimodal Brain-Tumor Segmentation Based on Dirichlet Process Mixture Model with Anisotropic Diffusion and Markov Random Field Prior

    Directory of Open Access Journals (Sweden)

    Yisu Lu

    2014-01-01

    Full Text Available Brain-tumor segmentation is an important clinical requirement for brain-tumor diagnosis and radiotherapy planning. It is well-known that the number of clusters is one of the most important parameters for automatic segmentation. However, it is difficult to define owing to the high diversity in appearance of tumor tissue among different patients and the ambiguous boundaries of lesions. In this study, a nonparametric mixture of Dirichlet process (MDP model is applied to segment the tumor images, and the MDP segmentation can be performed without the initialization of the number of clusters. Because the classical MDP segmentation cannot be applied for real-time diagnosis, a new nonparametric segmentation algorithm combined with anisotropic diffusion and a Markov random field (MRF smooth constraint is proposed in this study. Besides the segmentation of single modal brain-tumor images, we developed the algorithm to segment multimodal brain-tumor images by the magnetic resonance (MR multimodal features and obtain the active tumor and edema in the same time. The proposed algorithm is evaluated using 32 multimodal MR glioma image sequences, and the segmentation results are compared with other approaches. The accuracy and computation time of our algorithm demonstrates very impressive performance and has a great potential for practical real-time clinical use.

  4. Multimodal Brain-Tumor Segmentation Based on Dirichlet Process Mixture Model with Anisotropic Diffusion and Markov Random Field Prior

    Science.gov (United States)

    Lu, Yisu; Jiang, Jun; Chen, Wufan

    2014-01-01

    Brain-tumor segmentation is an important clinical requirement for brain-tumor diagnosis and radiotherapy planning. It is well-known that the number of clusters is one of the most important parameters for automatic segmentation. However, it is difficult to define owing to the high diversity in appearance of tumor tissue among different patients and the ambiguous boundaries of lesions. In this study, a nonparametric mixture of Dirichlet process (MDP) model is applied to segment the tumor images, and the MDP segmentation can be performed without the initialization of the number of clusters. Because the classical MDP segmentation cannot be applied for real-time diagnosis, a new nonparametric segmentation algorithm combined with anisotropic diffusion and a Markov random field (MRF) smooth constraint is proposed in this study. Besides the segmentation of single modal brain-tumor images, we developed the algorithm to segment multimodal brain-tumor images by the magnetic resonance (MR) multimodal features and obtain the active tumor and edema in the same time. The proposed algorithm is evaluated using 32 multimodal MR glioma image sequences, and the segmentation results are compared with other approaches. The accuracy and computation time of our algorithm demonstrates very impressive performance and has a great potential for practical real-time clinical use. PMID:25254064

  5. Markov random field-based statistical character structure modeling for handwritten Chinese character recognition.

    Science.gov (United States)

    Zeng, Jia; Liu, Zhi-Qiang

    2008-05-01

    This paper proposes a statistical-structural character modeling method based on Markov random fields (MRFs) for handwritten Chinese character recognition (HCCR). The stroke relationships of a Chinese character reflect its structure, which can be statistically represented by the neighborhood system and clique potentials within the MRF framework. Based on the prior knowledge of character structures, we design the neighborhood system that accounts for the most important stroke relationships. We penalize the structurally mismatched stroke relationships with MRFs using the prior clique potentials, and derive the likelihood clique potentials from Gaussian mixture models, which encode the large variations of stroke relationships statistically. In the proposed HCCR system, we use the single-site likelihood clique potentials to extract many candidate strokes from character images, and use the pairsite clique potentials to determine the best structural match between the input candidate strokes and the MRF-based character models by relaxation labeling. The experiments on the KAIST character database demonstrate that MRFs can statistically model character structures, and work well in the HCCR system.

  6. Random lasing action in a polydimethylsiloxane wrinkle induced disordered structure

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Zhenhua; Wu, Leilei; Zhu, Shu; Zheng, Yuanlin; Chen, Xianfeng, E-mail: xfchen@sjtu.edu.cn [The State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2014-07-14

    This paper presents a chip-scale random lasing action utilizing polydimethylsiloxane (PDMS) wrinkles with random periods as disordered medium. Nanoscale wrinkles with long range disorder structures are formed on the oxidized surface of a PDMS slab and confirmed by atomic force microscopy. Light multiply scattered at each PDMS wrinkle-dye interfaces is optically amplified in the presence of pump gain. The shift of laser emission wavelength when pumping at different regions indicates the randomness of the winkle period. In addition, a relatively low threshold of about 27 μJ/mm{sup 2} is realized, which is comparable with traditional optofluidic dye laser. This is due to the unique sinusoidal Bragg-grating-like random structure. Contrast to conventional microfluidic dye laser that inevitably requires the accurate design and implementation of microcavity to provide optical feedback, the convenience in both fabrication and operation makes PDMS wrinkle based random laser a promising underlying element in lab-on-a-chip systems and integrated microfluidic networks.

  7. Random lasing action in a polydimethylsiloxane wrinkle induced disordered structure

    Science.gov (United States)

    Shen, Zhenhua; Wu, Leilei; Zhu, Shu; Zheng, Yuanlin; Chen, Xianfeng

    2014-07-01

    This paper presents a chip-scale random lasing action utilizing polydimethylsiloxane (PDMS) wrinkles with random periods as disordered medium. Nanoscale wrinkles with long range disorder structures are formed on the oxidized surface of a PDMS slab and confirmed by atomic force microscopy. Light multiply scattered at each PDMS wrinkle-dye interfaces is optically amplified in the presence of pump gain. The shift of laser emission wavelength when pumping at different regions indicates the randomness of the winkle period. In addition, a relatively low threshold of about 27 μJ/mm2 is realized, which is comparable with traditional optofluidic dye laser. This is due to the unique sinusoidal Bragg-grating-like random structure. Contrast to conventional microfluidic dye laser that inevitably requires the accurate design and implementation of microcavity to provide optical feedback, the convenience in both fabrication and operation makes PDMS wrinkle based random laser a promising underlying element in lab-on-a-chip systems and integrated microfluidic networks.

  8. Response of Launch Pad Structures to Random Acoustic Excitation

    Directory of Open Access Journals (Sweden)

    Ravi N. Margasahayam

    1994-01-01

    Full Text Available The design of launch pad structures, particularly those having a large area-to-mass ratio, is governed by launch-induced acoustics, a relatively short transient with random pressure amplitudes having a non-Gaussian distribution. The factors influencing the acoustic excitation and resulting structural responses are numerous and cannot be predicted precisely. Two solutions (probabilistic and deterministic for the random vibration problem are presented in this article from the standpoint of their applicability to predict the response of ground structures exposed to rocket noise. Deficiencies of the probabilistic method, especially to predict response in the low-frequency range of launch transients (below 20 Hz, prompted the development of the deterministic analysis. The relationship between the two solutions is clarified for future implementation in a finite element method (FEM code.

  9. Cell population structure prior to bifurcation predicts efficiency of directed differentiation in human induced pluripotent cells.

    Science.gov (United States)

    Bargaje, Rhishikesh; Trachana, Kalliopi; Shelton, Martin N; McGinnis, Christopher S; Zhou, Joseph X; Chadick, Cora; Cook, Savannah; Cavanaugh, Christopher; Huang, Sui; Hood, Leroy

    2017-02-28

    Steering the differentiation of induced pluripotent stem cells (iPSCs) toward specific cell types is crucial for patient-specific disease modeling and drug testing. This effort requires the capacity to predict and control when and how multipotent progenitor cells commit to the desired cell fate. Cell fate commitment represents a critical state transition or "tipping point" at which complex systems undergo a sudden qualitative shift. To characterize such transitions during iPSC to cardiomyocyte differentiation, we analyzed the gene expression patterns of 96 developmental genes at single-cell resolution. We identified a bifurcation event early in the trajectory when a primitive streak-like cell population segregated into the mesodermal and endodermal lineages. Before this branching point, we could detect the signature of an imminent critical transition: increase in cell heterogeneity and coordination of gene expression. Correlation analysis of gene expression profiles at the tipping point indicates transcription factors that drive the state transition toward each alternative cell fate and their relationships with specific phenotypic readouts. The latter helps us to facilitate small molecule screening for differentiation efficiency. To this end, we set up an analysis of cell population structure at the tipping point after systematic variation of the protocol to bias the differentiation toward mesodermal or endodermal cell lineage. We were able to predict the proportion of cardiomyocytes many days before cells manifest the differentiated phenotype. The analysis of cell populations undergoing a critical state transition thus affords a tool to forecast cell fate outcomes and can be used to optimize differentiation protocols to obtain desired cell populations.

  10. POROSIMETRY BY RANDOM NODE STRUCTURING IN VIRTUAL CONCRETE

    Directory of Open Access Journals (Sweden)

    Piet Stroeven

    2012-05-01

    Full Text Available Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of the aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. However, aggregate grain surfaces lead to anisotropy in porosity. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS, introduced earlier in IA&S (Stroeven et al., 2011b and random node structuring (RaNoS provide such information.

  11. Exploring biological network structure with clustered random networks

    Directory of Open Access Journals (Sweden)

    Bansal Shweta

    2009-12-01

    Full Text Available Abstract Background Complex biological systems are often modeled as networks of interacting units. Networks of biochemical interactions among proteins, epidemiological contacts among hosts, and trophic interactions in ecosystems, to name a few, have provided useful insights into the dynamical processes that shape and traverse these systems. The degrees of nodes (numbers of interactions and the extent of clustering (the tendency for a set of three nodes to be interconnected are two of many well-studied network properties that can fundamentally shape a system. Disentangling the interdependent effects of the various network properties, however, can be difficult. Simple network models can help us quantify the structure of empirical networked systems and understand the impact of various topological properties on dynamics. Results Here we develop and implement a new Markov chain simulation algorithm to generate simple, connected random graphs that have a specified degree sequence and level of clustering, but are random in all other respects. The implementation of the algorithm (ClustRNet: Clustered Random Networks provides the generation of random graphs optimized according to a local or global, and relative or absolute measure of clustering. We compare our algorithm to other similar methods and show that ours more successfully produces desired network characteristics. Finding appropriate null models is crucial in bioinformatics research, and is often difficult, particularly for biological networks. As we demonstrate, the networks generated by ClustRNet can serve as random controls when investigating the impacts of complex network features beyond the byproduct of degree and clustering in empirical networks. Conclusion ClustRNet generates ensembles of graphs of specified edge structure and clustering. These graphs allow for systematic study of the impacts of connectivity and redundancies on network function and dynamics. This process is a key step in

  12. Exploring biological network structure with clustered random networks.

    Science.gov (United States)

    Bansal, Shweta; Khandelwal, Shashank; Meyers, Lauren Ancel

    2009-12-09

    Complex biological systems are often modeled as networks of interacting units. Networks of biochemical interactions among proteins, epidemiological contacts among hosts, and trophic interactions in ecosystems, to name a few, have provided useful insights into the dynamical processes that shape and traverse these systems. The degrees of nodes (numbers of interactions) and the extent of clustering (the tendency for a set of three nodes to be interconnected) are two of many well-studied network properties that can fundamentally shape a system. Disentangling the interdependent effects of the various network properties, however, can be difficult. Simple network models can help us quantify the structure of empirical networked systems and understand the impact of various topological properties on dynamics. Here we develop and implement a new Markov chain simulation algorithm to generate simple, connected random graphs that have a specified degree sequence and level of clustering, but are random in all other respects. The implementation of the algorithm (ClustRNet: Clustered Random Networks) provides the generation of random graphs optimized according to a local or global, and relative or absolute measure of clustering. We compare our algorithm to other similar methods and show that ours more successfully produces desired network characteristics.Finding appropriate null models is crucial in bioinformatics research, and is often difficult, particularly for biological networks. As we demonstrate, the networks generated by ClustRNet can serve as random controls when investigating the impacts of complex network features beyond the byproduct of degree and clustering in empirical networks. ClustRNet generates ensembles of graphs of specified edge structure and clustering. These graphs allow for systematic study of the impacts of connectivity and redundancies on network function and dynamics. This process is a key step in unraveling the functional consequences of the structural

  13. Spatial Random Sampling: A Structure-Preserving Data Sketching Tool

    Science.gov (United States)

    Rahmani, Mostafa; Atia, George K.

    2017-09-01

    Random column sampling is not guaranteed to yield data sketches that preserve the underlying structures of the data and may not sample sufficiently from less-populated data clusters. Also, adaptive sampling can often provide accurate low rank approximations, yet may fall short of producing descriptive data sketches, especially when the cluster centers are linearly dependent. Motivated by that, this paper introduces a novel randomized column sampling tool dubbed Spatial Random Sampling (SRS), in which data points are sampled based on their proximity to randomly sampled points on the unit sphere. The most compelling feature of SRS is that the corresponding probability of sampling from a given data cluster is proportional to the surface area the cluster occupies on the unit sphere, independently from the size of the cluster population. Although it is fully randomized, SRS is shown to provide descriptive and balanced data representations. The proposed idea addresses a pressing need in data science and holds potential to inspire many novel approaches for analysis of big data.

  14. In a randomized trial, the live attenuated tetravalent dengue vaccine TV003 is well-tolerated and highly immunogenic in subjects with flavivirus exposure prior to vaccination

    Science.gov (United States)

    Whitehead, Stephen S.; Durbin, Anna P.; Pierce, Kristen K.; Elwood, Dan; McElvany, Benjamin D.; Fraser, Ellen A.; Carmolli, Marya P.; Tibery, Cecilia M.; Hynes, Noreen A.; Jo, Matthew; Lovchik, Janece M.; Larsson, Catherine J.; Doty, Elena A.; Dickson, Dorothy M.; Luke, Catherine J.; Subbarao, Kanta; Kirkpatrick, Beth D.

    2017-01-01

    Infection caused by the four serotypes of dengue virus (DENV-1-4) is a leading cause of mosquito-borne disease. Clinically-severe dengue disease is more common when secondary dengue infection occurs following prior infection with a heterologous dengue serotype. Other flaviviruses such as yellow fever virus, Japanese encephalitis virus, and Zika virus, can also elicit antibodies which are cross-reactive to DENV. As candidate dengue vaccines become available in endemic settings and for individuals who have received other flavivirus vaccines, it is important to examine vaccine safety and immunogenicity in these flavivirus-experienced populations. We performed a randomized, controlled trial of the National Institutes of Health live attenuated tetravalent dengue vaccine candidate (TV003) in fifty-eight individuals with prior exposure to flavivirus infection or vaccine. As in prior studies of this vaccine in flavivirus-naive volunteers, flavivirus-experienced subjects received two doses of vaccine six months apart and were followed closely for clinical events, laboratory changes, viremia, and neutralizing antibody titers. TV003 was well tolerated with few adverse events other than rash, which was predominately mild. Following one dose, 87% of vaccinees had an antibody response to all four serotypes (tetravalent response), suggesting a robust immune response. In addition, 76% of vaccinees were viremic; mean peak titers ranged from 0.68–1.1 log10 PFU/mL and did not differ by serotype. The second dose of TV003 was not associated with viremia, rash, or a sustained boost in antibody titers indicating that a single dose of the vaccine is likely sufficient to prevent viral replication and thus protect against disease. In comparison to the viremia and neutralizing antibody response elicited by TV003 in flavivirus-naïve subjects from prior studies, we found that subjects who were flavivirus-exposed prior to vaccination exhibited slightly higher DENV-3 viremia, higher

  15. Moisture diffusivity in structure of random fractal fiber bed

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Fanglong, E-mail: zhufanglong_168@163.com [College of Textile, Zhongyuan University of Technology, Zhengzhou City (China); The Chinese People' s Armed Police Forces Academy, Langfan City (China); Zhou, Yu; Feng, Qianqian [College of Textile, Zhongyuan University of Technology, Zhengzhou City (China); Xia, Dehong [School of Mechanical Engineering, University of Science and Technology, Beijing (China)

    2013-11-08

    A theoretical expression related to effective moisture diffusivity to random fiber bed is derived by using fractal theory and considering both parallel and perpendicular channels to diffusion flow direction. In this Letter, macroporous structure of hydrophobic nonwoven material is investigated, and Knudsen diffusion and surface diffusion are neglected. The effective moisture diffusivity predicted by the present fractal model are compared with water vapor transfer rate (WVTR) experiment data and calculated values obtained from other theoretical models. This verifies the validity of the present fractal diffusivity of fibrous structural beds.

  16. The Fatigue Behavior of Steel Structures under Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning

    2008-01-01

    Fatigue damage accumulation in steel structures under random loading has been studied in a number of investigations at the Technical University of Denmark. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part...... of the investigation, fatigue test series with a total of 540 fatigue tests have been carried through on various types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel or high-strength steel. The fatigue tests...... and the fracture mechanics analyses have been carried out using load histories, which are realistic in relation to the types of structures studied, i.e. primarily bridges, offshore structures and chimneys. In general, the test series carried through show a significant difference between constant amplitude...

  17. The Fatigue Behavior of Steel Structures under Random Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning

    2009-01-01

    Fatigue damage accumulation in steel structures under random loading has been studied in a number of investigations at the Technical University of Denmark. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part...... of the investigation, fatigue test series with a total of 540 fatigue tests have been carried through on various types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel or high-strength steel. The fatigue tests...... and variable amplitude fatigue test results. Both the fracture mechanics analysis and the fatigue test results indicate that Miner’s rule, which is normally used in the design against fatigue in steel structures, may give results, which are unconservative, and that the validity of the results obtained from...

  18. Random field Ising model and community structure in complex networks

    Science.gov (United States)

    Son, S.-W.; Jeong, H.; Noh, J. D.

    2006-04-01

    We propose a method to determine the community structure of a complex network. In this method the ground state problem of a ferromagnetic random field Ising model is considered on the network with the magnetic field Bs = +∞, Bt = -∞, and Bi≠s,t=0 for a node pair s and t. The ground state problem is equivalent to the so-called maximum flow problem, which can be solved exactly numerically with the help of a combinatorial optimization algorithm. The community structure is then identified from the ground state Ising spin domains for all pairs of s and t. Our method provides a criterion for the existence of the community structure, and is applicable equally well to unweighted and weighted networks. We demonstrate the performance of the method by applying it to the Barabási-Albert network, Zachary karate club network, the scientific collaboration network, and the stock price correlation network. (Ising, Potts, etc.)

  19. Active control of tensegrity structures under random excitation

    Science.gov (United States)

    Ganesh Raja, M.; Narayanan, S.

    2007-06-01

    In this paper we consider vibration control of tensegrity structures under stationary and nonstationary random excitations. These excitations may be representative of many physical loading conditions, such as earthquake, wind, aerodynamic and acoustic excitations. The optimal control theory based on H2 and \\mathrm {H}_{\\infty } controller with full state and limited state feedback is used for the control. The response of the tensegrity structure is represented by the zero lag covariance matrix and the same is obtained by solving the matrix Lyapunov equation. The force generated by the electro-mechanical coupling of the piezoelectric actuator is used in the formulation. A tensegrity structure of class-1 comprising of two modules, with 24 pretension cables and six struts with piezoelectric actuators, is considered.

  20. Gabapentin reduces preoperative anxiety and pain catastrophizing in highly anxious patients prior to major surgery: a blinded randomized placebo-controlled trial.

    Science.gov (United States)

    Clarke, Hance; Kirkham, Kyle R; Orser, Beverley A; Katznelson, Rita; Mitsakakis, Nicholas; Ko, Raynauld; Snyman, Adam; Ma, Martin; Katz, Joel

    2013-05-01

    Gabapentin is increasingly being used for the treatment of postoperative pain and a variety of psychiatric diseases, including chronic anxiety disorders. Trials have reported mixed results when gabapentin has been administered for the treatment of preoperative anxiety. We tested the hypothesis that gabapentin 1,200 mg vs placebo would reduce preoperative anxiety in patients who exhibit moderate to high preoperative anxiety. A blinded randomized controlled trial was conducted from September 2009 to June 2011 at the Toronto General Hospital. Following ethics approval and informed consent, 50 female patients with a 0-10 numeric rating scale (NRS) anxiety score of greater than or equal to 5/10 consented to receive either gabapentin 1,200 mg (n = 25) or placebo (n = 25) prior to surgery. Randomization was computer generated, and the Investigational Pharmacy was responsible for the blinding and dispensing of medication. All patients and care providers, including physicians, nurses, and study personnel, were blinded to group allocation. Before administering the study medication, baseline anxiety levels were measured using a NRS, the Spielberger State-Trait Anxiety Inventories, the Pain Catastrophizing Scale, and the Pain Anxiety Symptoms Scale-20. Baseline pain intensity (0-10 NRS) and level of sedation (0-10 NRS and Richmond Agitation-Sedation Scale [RASS]) were also measured. Two hours after the administration of gabapentin or placebo (prior to surgery), patients again rated their anxiety, pain, and sedation levels using the same measurement tools as at baseline. The main outcome was a reduction in preoperative anxiety. Forty-four patients (22 treated with gabapentin 1,200 mg and 22 treated with placebo) were included in the analysis of the primary outcome. Analysis of covariance in which pre-drug NRS anxiety scores were used as the covariate showed that post-drug preoperative NRS anxiety (Effect size, 1.44; confidence interval [CI] 0.19 to 2.70) and pain

  1. A Double Blind, Randomized, Neoadjuvant Study of the Tissue effects of POMx Pills in Men with Prostate Cancer Prior to Radical Prostatectomy

    Science.gov (United States)

    Freedland, Stephen J.; Carducci, Michael; Kroeger, Nils; Partin, Alan; Rao, Jian-yu; Jin, Yusheng; Kerkoutian, Susan; Wu, Hong; Li, Yunfeng; Creel, Patricia; Mundy, Kelly; Gurganus, Robin; Fedor, Helen; King, Serina A.; Zhang, Yanjun; Heber, David; Pantuck, Allan J.

    2013-01-01

    Pomegranates slow prostate cancer xenograft growth and prolong PSA doubling times in single-arm human studies. Pomegranates’ effects on human prostate tissue are understudied. We hypothesized orally administered pomegranate extract (POMx; PomWonderful, Los Angeles, CA) would lower tissue 8-hydroxy-2-deoxyguanosine (8-OHdG), an oxidative stress biomarker. 70 men were randomized to 2 tablets POMx or placebo daily up to 4 weeks prior to radical prostatectomy. Tissue was analyzed for intra-prostatic Urolithin A, a pomegranate metabolite, benign and malignant 8-OHdG, and cancer pS6 kinase, NFκB, and Ki67. Primary end-point was differences in 8-OHdG powered to detect 30% reduction. POMx was associated with 16% lower benign tissue 8-OHdG (p=0.095), which was not statistically significant. POMx was well-tolerated with no treatment-related withdrawals. There were no differences in baseline clinicopathological features between arms. Urolithin A was detected in 21/33 patient in the POMx group vs. 12/35 in the placebo group (p=0.031). Cancer pS6 kinase, NFκB, Ki67, and serum PSA changes were similar between arms. POMx prior to surgery results in pomegranate metabolite accumulation in prostate tissues. Our primary end-point in this modest-sized short-term trial was negative. Future larger longer studies are needed to more definitely test whether POMx reduces prostate oxidative stress as well as further animal testing to better understand the multiple mechanisms through which POMx may alter prostate cancer biology. PMID:23985577

  2. Exponential random graph models for networks with community structure.

    Science.gov (United States)

    Fronczak, Piotr; Fronczak, Agata; Bujok, Maksymilian

    2013-09-01

    Although the community structure organization is an important characteristic of real-world networks, most of the traditional network models fail to reproduce the feature. Therefore, the models are useless as benchmark graphs for testing community detection algorithms. They are also inadequate to predict various properties of real networks. With this paper we intend to fill the gap. We develop an exponential random graph approach to networks with community structure. To this end we mainly built upon the idea of blockmodels. We consider both the classical blockmodel and its degree-corrected counterpart and study many of their properties analytically. We show that in the degree-corrected blockmodel, node degrees display an interesting scaling property, which is reminiscent of what is observed in real-world fractal networks. A short description of Monte Carlo simulations of the models is also given in the hope of being useful to others working in the field.

  3. Maps of random walks on complex networks reveal community structure.

    Science.gov (United States)

    Rosvall, Martin; Bergstrom, Carl T

    2008-01-29

    To comprehend the multipartite organization of large-scale biological and social systems, we introduce an information theoretic approach that reveals community structure in weighted and directed networks. We use the probability flow of random walks on a network as a proxy for information flows in the real system and decompose the network into modules by compressing a description of the probability flow. The result is a map that both simplifies and highlights the regularities in the structure and their relationships. We illustrate the method by making a map of scientific communication as captured in the citation patterns of >6,000 journals. We discover a multicentric organization with fields that vary dramatically in size and degree of integration into the network of science. Along the backbone of the network-including physics, chemistry, molecular biology, and medicine-information flows bidirectionally, but the map reveals a directional pattern of citation from the applied fields to the basic sciences.

  4. Influence of DC plasma modification on the selected properties and the geometrical surface structure of polylactide prior to autocatalytic metallization

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, Marii Skłodowskiej-Curie 55, 87-100 Toruń (Poland); Tracz, Adam [Centre for Molecular and Macromolecular Studies of the Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź (Poland); Żenkiewicz, Marian [Institute for Engineering of Polymer Materials and Dyes, Marii Skłodowskiej-Curie 55, 87-100 Toruń (Poland)

    2015-03-01

    The paper presents the results of studies to determine the applicability of plasma modification in the process of polylactide (PLA) surface preparation prior to the autocatalytic metallization. The polylactide plasma modification was carried out in an oxygen or nitrogen chemistry. The samples were tested with the following methods: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and electron spectrophotometry (XPS). Scanning electron microscopy and atomic force microscopy images were demonstrated. The results of surface free energy calculations, performed based on the results of the contact angle measurements have been presented. The results of the qualitative (degree of oxidation or nitridation) and quantitative analysis of the chemical composition of the polylactide surface layer have also been described. The results of the studies show that the DC plasma modification performed in the proposed condition is a suitable as a method of surface preparation for the polylactide metallization. - Highlights: • We modified polylactide surface layer with plasma generated in oxygen or nitrogen. • We tested selected properties and surface structure of modified samples. • DC plasma modification can be used to prepare the PLA surface for metallization. • For better results metallization should be preceded by sonication process.

  5. Translation of representations of the structure of matter and its relationship to reasoning, gender, spatial reasoning, and specific prior knowledge

    Science.gov (United States)

    Keig, Patricia F.; Rubba, Peter A.

    . The associated interview schedule was entitled Translation of Representations - Structure of Matter [TORSOM]. Reasoning ability was measured by the Group Assessment of Logical Thinking - short form (GALT-s), spatial reasoning ability by the spatial reasoning subtest of the Differential Abilities Test (SRDAT), and prior knowledge of the representations by a test developed by the first researcher (Knowledge of Representations - Structure of Matter). When each of the hypothetical correlates were regressed on TORSOM individually, results indicated the KORSOM and GALT-s but not gender or SRDAT were statistically significant (alpha = .05). The two-predictor model accounts for 28% of the variance in the TORSOM scores. Representation error types are described and exemplified.

  6. Conditional Random Fields for Pattern Recognition Applied to Structured Data

    Directory of Open Access Journals (Sweden)

    Tom Burr

    2015-07-01

    Full Text Available Pattern recognition uses measurements from an input domain, X, to predict their labels from an output domain, Y. Image analysis is one setting where one might want to infer whether a pixel patch contains an object that is “manmade” (such as a building or “natural” (such as a tree. Suppose the label for a pixel patch is “manmade”; if the label for a nearby pixel patch is then more likely to be “manmade” there is structure in the output domain that can be exploited to improve pattern recognition performance. Modeling P(X is difficult because features between parts of the model are often correlated. Therefore, conditional random fields (CRFs model structured data using the conditional distribution P(Y|X = x, without specifying a model for P(X, and are well suited for applications with dependent features. This paper has two parts. First, we overview CRFs and their application to pattern recognition in structured problems. Our primary examples are image analysis applications in which there is dependence among samples (pixel patches in the output domain. Second, we identify research topics and present numerical examples.

  7. A Geometric-Structure Theory for Maximally Random Jammed Packings.

    Science.gov (United States)

    Tian, Jianxiang; Xu, Yaopengxiao; Jiao, Yang; Torquato, Salvatore

    2015-11-16

    Maximally random jammed (MRJ) particle packings can be viewed as prototypical glasses in that they are maximally disordered while simultaneously being mechanically rigid. The prediction of the MRJ packing density ϕMRJ, among other packing properties of frictionless particles, still poses many theoretical challenges, even for congruent spheres or disks. Using the geometric-structure approach, we derive for the first time a highly accurate formula for MRJ densities for a very wide class of two-dimensional frictionless packings, namely, binary convex superdisks, with shapes that continuously interpolate between circles and squares. By incorporating specific attributes of MRJ states and a novel organizing principle, our formula yields predictions of ϕMRJ that are in excellent agreement with corresponding computer-simulation estimates in almost the entire α-x plane with semi-axis ratio α and small-particle relative number concentration x. Importantly, in the monodisperse circle limit, the predicted ϕMRJ = 0.834 agrees very well with the very recently numerically discovered MRJ density of 0.827, which distinguishes it from high-density "random-close packing" polycrystalline states and hence provides a stringent test on the theory. Similarly, for non-circular monodisperse superdisks, we predict MRJ states with densities that are appreciably smaller than is conventionally thought to be achievable by standard packing protocols.

  8. Emergence of patterns in random processes. II. Stochastic structure in random events.

    Science.gov (United States)

    Newman, William I

    2014-06-01

    Random events can present what appears to be a pattern in the length of peak-to-peak sequences in time series and other point processes. Previously, we showed that this was the case in both individual and independently distributed processes as well as for Brownian walks. In addition, we introduced the use of the discrete form of the Langevin equation of statistical mechanics as a device for connecting the two limiting sets of behaviors, which we then compared with a variety of observations from the physical and social sciences. Here, we establish a probabilistic framework via the Smoluchowski equation for exploring the Langevin equation and its expected peak-to-peak sequence lengths, and we introduce a concept we call "stochastic structure in random events," or SSRE. We extend the Brownian model to include antipersistent processes via autoregressive (AR) models. We relate the latter to describe the behavior of Old Faithful Geyser in Yellowstone National Park, and we devise a further test for the validity of the Langevin and AR models. Given our analytic results, we show how the Langevin equation can be adapted to describe population cycles of three to four years observed among many mammalian species in biology.

  9. Double-blind Randomized Controlled Trial of Intranasal Dexmedetomidine Versus Intranasal Midazolam as Anxiolysis Prior to Pediatric Laceration Repair in the Emergency Department.

    Science.gov (United States)

    Neville, Desiree N W; Hayes, Katharina R; Ivan, Yaron; McDowell, Erin R; Pitetti, Raymond D

    2016-08-01

    The objective of this study was to compare anxiolysis with intranasal dexmedetomidine, an alpha-2 agonist, versus intranasal midazolam for pediatric laceration repairs. We performed a double-blind, randomized controlled trial of 40 patients 1-5 years with lacerations requiring suture repair in an academic pediatric emergency department (ED). Patients were randomized to receive either intranasal dexmedetomidine or intranasal midazolam. Our primary outcome measure was the anxiety score at the time of patient positioning for the laceration repair. We chose this time point to isolate the anxiolysis from the medications prior to intervention. Patient encounters were videotaped and scored for anxiety at multiple time points using the modified Yale Preoperative Anxiety Scale. The scale is 23.3-100 with higher scores indicating higher anxiety. We also evaluated these scores as a secondary outcome by dichotomizing them into anxious versus not anxious with a previously validated score cutoff. Of the 40 patients enrolled, 20 in the dexmedetomidine group and 18 in the midazolam group completed the study and were included in the analysis. The median age was 3.3 years (range = 1.0-5.4 years). The median baseline anxiety score was 48.3. The anxiety score at position for procedure for patients receiving dexmedetomidine was 9.2 points lower than those receiving midazolam (median difference = 9.2, 95% confidence interval = 5 to 13.3; median score for dexmedetomidine = 23.3, median score for midazolam = 36.3). The proportion of patients who were classified as not anxious at the position for procedure was significantly higher in the dexmedetomidine group (70%) versus the midazolam group (11%). The number needed to treat with dexmedetomidine instead of midazolam to obtain the result of a not anxious patient at this time point was 1.7 patients. There were also significantly more patients who were classified as not anxious at the time of wound washout in the dexmedetomidine

  10. Can log-periodic power law structures arise from random fluctuations?

    Science.gov (United States)

    Wosnitza, Jan Henrik; Leker, Jens

    2014-05-01

    Recent research has established log-periodic power law (LPPL) patterns prior to the detonation of the German stock index (DAX) bubble in 1998. The purpose of this article is to explore whether a Langevin equation extracted from real world data can generate synthetic time series with comparable LPPL structures. To this end, we first estimate the stochastic process underlying the DAX log-returns during the period from mid-1997 until end-2003. The employed data set contains about 3.93ṡ106 intraday DAX quotes at a sampling rate of 15 s. Our results indicate that the DAX log-returns can be described as a Markov process. As a consequence, a Langevin equation is derived. Based on this model equation, we run extensive simulations in order to generate 100 synthetic DAX trajectories each covering 3000 trading days. We find LPPL behavior in ten artificial time series. Moreover, we can establish a link between LPPL patterns and ensuing bubble bursts in seven synthetic 600-week windows. However, the LPPL components in most synthetic trajectories differ fundamentally from those LPPL structures that have previously been detected in real financial time series. Summarized, this paper demonstrates that LPPL structures are not necessarily the signature of imitative behavior among investors but can also stem from noise, even though the likelihood of this is extremely low. Thus, our findings confirm with high statistical confidence that the LPPL structures in the DAX development are rooted deeper than only in the random fluctuations of the German stock market.

  11. Spatial location identification of structural nonlinearities from random data

    Science.gov (United States)

    Josefsson, A.; Magnevall, M.; Ahlin, K.; Broman, G.

    2012-02-01

    With growing demands on product performance and growing complexity of engineering structures, efficient tools for analyzing their dynamic behavior are essential. Linear techniques are well developed and often utilized. However, sometimes the errors due to linearization are too large to be acceptable, making it necessary to take nonlinear effects into account. In many practical applications it is common and reasonable to assume that the nonlinearities are highly local and thus only affect a limited set of spatial coordinates. The purpose of this paper is to present an approach to finding the spatial location of nonlinearities from measurement data, as this may not always be known beforehand. This information can be used to separate the underlying linear system from the nonlinear parts and create mathematical models for efficient parameter estimation and simulation. The presented approach builds on the reverse-path methodology and utilizes the coherence functions to determine the location of nonlinear elements. A systematic search with Multiple Input/Single Output models is conducted in order to find the nonlinear functions that best describe the nonlinear restoring forces. The obtained results indicate that the presented approach works well for identifying the location of local nonlinearities in structures. It is verified by simulation data from a cantilever beam model with two local nonlinearities and experimental data from a T-beam experimental set-up with a single local nonlinearity. A possible drawback is that a relatively large amount of data is needed. Advantages of the approach are that it only needs a single excitation point that response data at varying force amplitudes is not needed and that no prior information about the underlying linear system is needed.

  12. Perturbation Solutions for Random Linear Structural Systems subject to Random Excitation using Stochastic Differential Equations

    DEFF Research Database (Denmark)

    Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.

    1994-01-01

    The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order perturbat......The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order...... for multi-degree-of-freedom (MDOF) systems and the method is illustrated for a single-degree-of-freedom (SDOF) oscillator. The results are compared to those of exact results for a random oscillator subject to white noise excitation with random intensity....

  13. Photonic stop bands of two-dimensional quasi-random structures based on macroporous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Mohammad Mahbubur; Ferre-Borrull, Josep; Pallares, Josep; Marsal, Lluis F. [Universitat Rovira i Virgili, Nano-electronic and Photonic Systems (NePhoS), Av. Paisos Catalans 26, 43007 Tarragona (Spain)

    2011-03-15

    The existence of photonic stop bands in macroporous silicon with a quasi-random structure transferred from nanoporous anodic alumina is studied. The quasi-random structure consists of a periodic triangular arrangement broken into domains of random orientation and size. By means of Finite-Difference Time-Domain simulation, transmittance spectra of the structure are calculated which show that stop bands exist for the TE polarization in the same frequency range it exist for periodic photonic crystals. For TM polarization local minima of the transmittance are predicted by the calculations. A general trend of the transmittance to decrease with increasing frequency is observed. The comparison with the transmittance for random structures shows that such trend is due to incoherent scattering caused by the degree of randomness of the structure (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Stochastic model reduction for robust dynamical characterization of structures with random parameters

    Science.gov (United States)

    Ghienne, Martin; Blanzé, Claude; Laurent, Luc

    2017-12-01

    In this paper, we characterize random eigenspaces with a non-intrusive method based on the decoupling of random eigenvalues from their corresponding random eigenvectors. This method allows us to estimate the first statistical moments of the random eigenvalues of the system with a reduced number of deterministic finite element computations. The originality of this work is to adapt the method used to estimate each random eigenvalue depending on a global accuracy requirement. This allows us to ensure a minimal computational cost. The stochastic model of the structure is thus reduced by exploiting specific properties of random eigenvectors associated with the random eigenfrequencies being sought. An indicator with no additional computation cost is proposed to identify when the method needs to be enhanced. Finally, a simple three-beam frame and an industrial structure illustrate the proposed approach.

  15. Inner structure of vehicular ensembles and random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Krbálek, Milan, E-mail: milan.krbalek@fjfi.cvut.cz; Hobza, Tomáš

    2016-05-06

    Highlights: • New class of random matrices (DUE) is proposed and analyzed in detail. • Approximation formula for level spacing distribution in DUE ensembles is analytically derived. • Connection between DUE and vehicular systems (analogical to a well-known link between GUE and Mexico buses) is presented. • It is shown that LS distribution of DUE matrices is the same as clearance distribution measured on expressways. - Abstract: We introduce a special class of random matrices (DUE) whose spectral statistics corresponds to statistics of microscopical quantities detected in vehicular flows. Comparing the level spacing distribution (for ordered eigenvalues in unfolded spectra of DUE matrices) with the time-clearance distribution extracted from various areas of the flux-density diagram (evaluated from original traffic data measured on Czech expressways with high occupancies) we demonstrate that the set of classical systems showing an universality associated with Random Matrix Ensembles can be extended by traffic systems.

  16. Single-dose lubiprostone along with split-dose PEG solution without dietary restrictions for bowel cleansing prior to colonoscopy: a randomized, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Stengel, Joel Z; Jones, David P

    2008-09-01

    Proper colonic cleansing prior to colonoscopy is paramount to ensuring complete mucosal visualization and polyp identification. In a double-blind fashion, we compared single-dose lubiprostone (24 microg) versus placebo pretreatment prior to a split-dose polyethylene glycol electrolyte (PEG-E) bowel preparation without dietary restriction to determine the efficacy, safety, and patient tolerability. Two hundred patients referred for outpatient colorectal cancer screening were randomized to receive a single-dose of unlabeled lubiprostone (24 microg) or placebo prior to a split-dose PEG-E bowel preparation without dietary restriction. The patients were surveyed prior to the colonoscopy on the tolerability of the bowel preparation, and any adverse events were recorded. The cleanliness of the colon was graded by the endoscopist during the procedure utilizing the Ottawa bowel preparation scale. One hundred ninety-one patients completed the study (95%). Split-dose PEG-E with lubiprostone pretreatment was found to be more effective at bowel cleansing in each segment of the colon when compared with split-dose PEG-E with placebo (P lubiprostone treatment arm rated the overall experience as more tolerable (P 0.003) and complained of less abdominal bloating (P 0.049). No differences were observed between the groups for treatment-emergent side effects or adverse events (P > 0.05). Single-dose lubiprostone prior to split-dose PEG-E without dietary restriction significantly improves colonic mucosa visualization during colonoscopy and is well tolerated by patients.

  17. Inner structure of vehicular ensembles and random matrix theory

    Science.gov (United States)

    Krbálek, Milan; Hobza, Tomáš

    2016-05-01

    We introduce a special class of random matrices (DUE) whose spectral statistics corresponds to statistics of microscopical quantities detected in vehicular flows. Comparing the level spacing distribution (for ordered eigenvalues in unfolded spectra of DUE matrices) with the time-clearance distribution extracted from various areas of the flux-density diagram (evaluated from original traffic data measured on Czech expressways with high occupancies) we demonstrate that the set of classical systems showing an universality associated with Random Matrix Ensembles can be extended by traffic systems.

  18. CheckMate 025 Randomized Phase 3 Study: Outcomes by Key Baseline Factors and Prior Therapy for Nivolumab Versus Everolimus in Advanced Renal Cell Carcinoma

    DEFF Research Database (Denmark)

    Escudier, Bernard; Sharma, Padmanee; McDermott, David F

    2017-01-01

    BACKGROUND: The randomized, phase 3 CheckMate 025 study of nivolumab (n=410) versus everolimus (n=411) in previously treated adults (75% male; 88% white) with advanced renal cell carcinoma (aRCC) demonstrated significantly improved overall survival (OS) and objective response rate (ORR). OBJECTIV...

  19. Slepian Simulations of Plastic Displacements of Randomly Excited Hysteretic Structures

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov

    2003-01-01

    The object of the study is a fast simulation method for generation and analysis of the plastic response of a randomly excited MDOF oscillatro with several potential elements with elasto-plastic constitutive behavior. The oscillator is statically determinate with linear damping. The external...... that are interesting for the plastic displacement process. These parts are those that are in the vicinity of the points of crossing of the response from the elastic domain to the plastic domain. The principle of the method is to use the known response properties at the crossing points of the stationary Gaussian white...... noise excited linear oscillator obtained from the elasto-plastic oscillator by totally removing the plastic domain. Thus the key to the applicability of the method is that the oscillator has a linear domain within which the response stays for a sufficiently long time to make the random response behave...

  20. Surface Structure of Hydrogenated Diamond-like Carbon: Origin of Run-In Behavior Prior to Superlubricious Interfacial Shear

    Energy Technology Data Exchange (ETDEWEB)

    Al-Azizi, Ala A; Eryilmaz, Osman; Erdemir, Ali; Kim, Seong H.

    2015-01-01

    The oxidized layers at the surface of hydrogenated diamond-like carbon (H-DLC) were studied with X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure, and Raman spectroscopy. The structure of these layers was correlated with the friction and wear behavior observed on H-DLC. H-DLC is well-known for its ultralow friction in inert environments, but the steady superlubricious state is always preceded by a run-in period with a high friction. It was hypothesized that the run-in period is related to the surface oxide layer formed naturally upon exposure of the sample to air. To test this hypothesis, thermal oxide layers were grown, and their structures were analyzed and compared with the native oxide layer on a pristine sample. It was found that the Raman spectra of the surface oxide layers of H-DLC have higher D/G band ratio than the bulk, indicating a larger amount of aromatic clusters compared to the bulk film. Thick oxide layers grown at 300 °C showed a run-in friction behavior that resembled the friction of graphite. The run-in periods were found to become longer when the thickness of the oxide layers increased, indicating that the run-in behavior of H-DLC is attributed to the removal of the surface oxide layers.

  1. Decision-making after continuous wins or losses in a randomized guessing task: implications for how the prior selection results affect subsequent decision-making.

    Science.gov (United States)

    Dong, Guangheng; Lin, Xiao; Zhou, Hongli; Du, Xiaoxia

    2014-04-03

    Human decision-making is often affected by prior selections and their outcomes, even in situations where decisions are independent and outcomes are unpredictable. In this study, we created a task that simulated real-life non-strategic gambling to examine the effect of prior outcomes on subsequent decisions in a group of male college students. Behavioral performance showed that participants needed more time to react after continuous losses (LOSS) than continuous wins (WIN) and discontinuous outcomes (CONTROL). In addition, participants were more likely to repeat their selections in both WIN and LOSS conditions. Functional MRI data revealed that decisions in WINs were associated with increased activation in the mesolimbic pathway, but decreased activation in the inferior frontal gyrus relative to LOSS. Increased prefrontal cortical activation was observed during LOSS relative to WIN and CONTROL conditions. Taken together, the behavioral and neuroimaging findings suggest that participants tended to repeat previous selections during LOSS trials, a pattern resembling the gambler's fallacy. However, during WIN trials, participants tended to follow their previous lucky decisions, like the 'hot hand' fallacy.

  2. The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive Performance, and Substrate Metabolism: A Randomized Controlled Trial.

    Science.gov (United States)

    Veasey, Rachel C; Haskell-Ramsay, Crystal F; Kennedy, David O; Wishart, Karl; Maggini, Silvia; Fuchs, Caspar J; Stevenson, Emma J

    2015-07-27

    Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G) has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI) 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max) 57.6 ± 7.3 mL/min/kg) completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE) during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males.

  3. The Effects of Supplementation with a Vitamin and Mineral Complex with Guaraná Prior to Fasted Exercise on Affect, Exertion, Cognitive Performance, and Substrate Metabolism: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Rachel C. Veasey

    2015-07-01

    Full Text Available Exercise undertaken in a fasted state can lead to higher post-exercise mental fatigue. The administration of a vitamin and mineral complex with guaraná (MVM + G has been shown to attenuate mental fatigue and improve performance during cognitively demanding tasks. This placebo-controlled, double-blind, randomized, balanced cross-over study examined the effect of MVM + G consumed prior to morning exercise on cognitive performance, affect, exertion, and substrate metabolism. Forty active males (age 21.4 ± 3.0 year; body mass index (BMI 24.0 ± 2.4 kg/m2; maximal oxygen consumption (V̇O2max 57.6 ± 7.3 mL/min/kg completed two main trials, consuming either MVM + G or placebo prior to a 30-min run at 60% V̇O2max. Supplementation prior to exercise led to a small but significant reduction in Rating of Perceived Exertion (RPE during exercise compared to the placebo. The MVM + G combination also led to significantly increased accuracy of numeric working memory and increased speed of picture recognition, compared to the placebo. There were no significant effects of supplementation on any other cognitive or mood measures or on substrate metabolism during exercise. These findings demonstrate that consuming a vitamin and mineral complex containing guaraná, prior to exercise, can positively impact subsequent memory performance and reduce perceived exertion during a moderate-intensity run in active males.

  4. Localized surface plasmon enhanced cellular imaging using random metallic structures

    Science.gov (United States)

    Son, Taehwang; Lee, Wonju; Kim, Donghyun

    2017-02-01

    We have studied fluorescence cellular imaging with randomly distributed localized near-field induced by silver nano-islands. For the fabrication of nano-islands, a 10-nm silver thin film evaporated on a BK7 glass substrate with an adhesion layer of 2-nm thick chromium. Micrometer sized silver square pattern was defined using e-beam lithography and then the film was annealed at 200°C. Raw images were restored using electric field distribution produced on the surface of random nano-islands. Nano-islands were modeled from SEM images. 488-nm p-polarized light source was set to be incident at 60°. Simulation results show that localized electric fields were created among nano-islands and that their average size was found to be 135 nm. The feasibility was tested using conventional total internal reflection fluorescence microscopy while the angle of incidence was adjusted to maximize field enhancement. Mouse microphage cells were cultured on nano-islands, and actin filaments were selectively stained with FITC-conjugated phalloidin. Acquired images were deconvolved based on linear imaging theory, in which molecular distribution was sampled by randomly distributed localized near-field and blurred by point spread function of far-field optics. The optimum fluorophore distribution was probabilistically estimated by repetitively matching a raw image. The deconvolved images are estimated to have a resolution in the range of 100-150 nm largely determined by the size of localized near-fields. We also discuss and compare the results with images acquired with periodic nano-aperture arrays in various optical configurations to excite localized plasmonic fields and to produce super-resolved molecular images.

  5. Random vectorial fields representing the local structure of turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Chevillard, Laurent [Laboratoire de Physique de l' ENS Lyon, CNRS, Universite de Lyon, 46 allee d' Italie, 69007 Lyon (France); Robert, Raoul [Institut Fourier, CNRS, Universite Grenoble 1, 100 rue des Mathematiques, BP 74, 38402 Saint-Martin d' Heres cedex (France); Vargas, Vincent, E-mail: laurent.chevillard@ens-lyon.fr [Ceremade, CNRS, Universite Paris-Dauphine, F-75016 Paris (France)

    2011-12-22

    We propose a method to build up a random homogeneous, isotropic and incompressible turbulent velocity field that mimics turbulence in the inertial range. The underlying Gaussian field is given by a modified Biot-Savart law. The long range correlated nature of turbulence is then incorporated heuristically using a non linear transformation inspired by the recent fluid deformation imposed by the Euler equations. The resulting velocity field shows a non vanishing mean energy transfer towards the small scales and realistic alignment properties of vorticity with the eigenframe of the deformation rate.

  6. Analytical and Experimental Random Vibration of Nonlinear Aeroelastic Structures.

    Science.gov (United States)

    1987-01-28

    dinamics . Sijthoff- Hilton, H H. and Feigen. M. Minimum weight analysis based on structural Noordhoff Co, Netherlands. reliability. J Aerospace Sc, 27...AEROELASTIC STRUCTURES January 28, 1987 ELECT Tpp. AIM" 0OV 7PTCE OF 9r(’TF1CP RESCH JAMi) NOTI-CE OF wIM 1 T AL TO D .TAC’ ..hirte;h-tz’ l rer)t ’(V...freedom aeroelastic structural model in the neighborhood of combination internal resonance condition. The Fokker:Planck equation approach is used to

  7. Transformation of frequency-magnitude relation prior to large events in the model of block structure dynamics

    Directory of Open Access Journals (Sweden)

    A. Soloviev

    2008-02-01

    Full Text Available The b-value change in the frequency-magnitude (FM distribution for a synthetic earthquake catalogue obtained by means of the model of block structure dynamics has been studied. The catalogue is divided into time periods preceding strong earthquakes and time periods that do not precede strong earthquakes. The separate analysis of these periods shows that the b-value is smaller before strong earthquakes. The similar phenomenon has been found also for the observed seismicity of the Southern California. The model of block structure dynamics represents a seismic region as a system of perfectly rigid blocks divided by infinitely thin plane faults. The blocks interact between themselves and with the underlying medium. The system of blocks moves as a consequence of prescribed motion of the boundary blocks and of the underlying medium. As the blocks are perfectly rigid, all deformation takes place in the fault zones and at the block base in contact with the underlying medium. Relative block displacements take place along the fault zones. Block motion is defined so that the system is in a quasistatic equilibrium state. The interaction of blocks along the fault zones is viscous-elastic ("normal state" while the ratio of the stress to the pressure remains below a certain strength level. When the critical level is exceeded in some part of a fault zone, a stress-drop ("failure" occurs (in accordance with the dry friction model, possibly causing failure in other parts of the fault zones. These failures produce earthquakes. Immediately after the earthquake and for some time after, the affected parts of the fault zones are in a state of creep. This state differs from the normal state because of a faster growth of inelastic displacements, lasting until the stress falls below some other level. This numerical simulation gives rise a synthetic earthquake catalogue.

  8. Completely random measures for modelling block-structured sparse networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Schmidt, Mikkel Nørgaard; Mørup, Morten

    2016-01-01

    Many statistical methods for network data parameterize the edge-probability by attributing latent traits to the vertices such as block structure and assume exchangeability in the sense of the Aldous-Hoover representation theorem. Empirical studies of networks indicate that many real-world networks...... [2014] proposed the use of a different notion of exchangeability due to Kallenberg [2006] and obtained a network model which admits power-law behaviour while retaining desirable statistical properties, however this model does not capture latent vertex traits such as block-structure. In this work we re......-introduce the use of block-structure for network models obeying allenberg’s notion of exchangeability and thereby obtain a model which admits the inference of block-structure and edge inhomogeneity. We derive a simple expression for the likelihood and an efficient sampling method. The obtained model...

  9. Phonon structures of GaN-based random semiconductor alloys

    Science.gov (United States)

    Zhou, Mei; Chen, Xiaobin; Li, Gang; Zheng, Fawei; Zhang, Ping

    2017-12-01

    Accurate modeling of thermal properties is strikingly important for developing next-generation electronics with high performance. Many thermal properties are closely related to phonon dispersions, such as sound velocity. However, random substituted semiconductor alloys AxB1-x usually lack translational symmetry, and simulation with periodic boundary conditions often requires large supercells, which makes phonon dispersion highly folded and hardly comparable with experimental results. Here, we adopt a large supercell with randomly distributed A and B atoms to investigate substitution effect on the phonon dispersions of semiconductor alloys systematically by using phonon unfolding method [F. Zheng, P. Zhang, Comput. Mater. Sci. 125, 218 (2016)]. The results reveal the extent to which phonon band characteristics in (In,Ga)N and Ga(N,P) are preserved or lost at different compositions and q points. Generally, most characteristics of phonon dispersions can be preserved with indium substitution of gallium in GaN, while substitution of nitrogen with phosphorus strongly perturbs the phonon dispersion of GaN, showing a rapid disintegration of the Bloch characteristics of optical modes and introducing localized impurity modes. In addition, the sound velocities of both (In,Ga)N and Ga(N,P) display a nearly linear behavior as a function of substitution compositions. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjb/e2017-80481-0.

  10. Understanding the structured processes followed by organisations prior to engaging in agile processes: A South African Perspective

    Directory of Open Access Journals (Sweden)

    Nimrod Noruwana

    2012-06-01

    Full Text Available There appears to be a lack of knowledge on the phases South African (SA organisations go through while adopting agile methods. As a means to address this gap, this study uncovered empirical evidence on the phases SA organisations go through whilst adopting agile methods as well as the disparities between agile prescriptions and the way SA organisations actually implement agile methods. The data collected using a case study approach was analysed through the lens of Actor-Network Theory (ANT. The results reveal that there is no structured process for adopting agile methods and organisations go through various phases in their attempts to adopt agile methods. During the various phases, organisations face challenges which are culture as well as people related. Through this study South African practitioners could now be aware that before adopting an agile methodology, there has to be a common understanding of the problems at hand and the envisioned solution. The findings also inform aspiring adopters in South Africa that adoption of the methods does not have to be as prescribed. They are free to adopt only those aspects the organisations need most.

  11. High-resolution structure of viruses from random diffraction snapshots

    CERN Document Server

    Hosseinizadeh, A; Dashti, A; Fung, R; D'Souza, R M; Ourmazd, A

    2014-01-01

    The advent of the X-ray Free Electron Laser (XFEL) has made it possible to record diffraction snapshots of biological entities injected into the X-ray beam before the onset of radiation damage. Algorithmic means must then be used to determine the snapshot orientations and thence the three-dimensional structure of the object. Existing Bayesian approaches are limited in reconstruction resolution typically to 1/10 of the object diameter, with the computational expense increasing as the eighth power of the ratio of diameter to resolution. We present an approach capable of exploiting object symmetries to recover three-dimensional structure to high resolution, and thus reconstruct the structure of the satellite tobacco necrosis virus to atomic level. Our approach offers the highest reconstruction resolution for XFEL snapshots to date, and provides a potentially powerful alternative route for analysis of data from crystalline and nanocrystalline objects.

  12. Electron avalanche structure determined by random walk theory

    Science.gov (United States)

    Englert, G. W.

    1973-01-01

    A self-consistent avalanche solution which accounts for collective long range Coulomb interactions as well as short range elastic and inelastic collisions between electrons and background atoms is made possible by a random walk technique. Results show that the electric field patterns in the early formation stages of avalanches in helium are close to those obtained from theory based on constant transport coefficients. Regions of maximum and minimum induced electrostatic potential phi are located on the axis of symmetry and within the volume covered by the electron swarm. As formation time continues, however, the region of minimum phi moves to slightly higher radii and the electric field between the extrema becomes somewhat erratic. In the intermediate formation periods the avalanche growth is slightly retarded by the high concentration of ions in the tail which oppose the external electric field. Eventually the formation of ions and electrons in the localized regions of high field strength more than offset this effect causing a very abrupt increase in avalanche growth.

  13. High-Resolution Structure of Viruses from Random Snapshots

    CERN Document Server

    Hosseinizadeh, A; Dashti, A; Fung, R; D'Souza, R M; Ourmazd, A

    2013-01-01

    The advent of the X-ray Free Electron Laser (XFEL) has made it possible to record snapshots of biological entities injected into the X-ray beam before the onset of radiation damage. Algorithmic means must then be used to determine the snapshot orientations and reconstruct the three-dimensional structure of the object. Existing approaches are limited in reconstruction resolution to at best 1/30th of the object diameter, with the computational expense increasing as the eighth power of the ratio of diameter to resolution. We present an approach capable of exploiting object symmetries to recover three-dimensional structure to 1/100th of the object diameter, and thus reconstruct the structure of the satellite tobacco necrosis virus to atomic resolution. Combined with the previously demonstrated capability to operate at ultralow signal, our approach offers the highest reconstruction resolution for XFEL snapshots to date, and provides a potentially powerful alternative route for analysis of data from crystalline and...

  14. Prior data for non-normal priors.

    Science.gov (United States)

    Greenland, Sander

    2007-08-30

    Data augmentation priors facilitate contextual evaluation of prior distributions and the generation of Bayesian outputs from frequentist software. Previous papers have presented approximate Bayesian methods using 2x2 tables of 'prior data' to represent lognormal relative-risk priors in stratified and regression analyses. The present paper describes extensions that use the tables to represent generalized-F prior distributions for relative risks, which subsume lognormal priors as a limiting case. The method provides a means to increase tail-weight or skew the prior distribution for the log relative risk away from normality, while retaining the simple 2x2 table form of the prior data. When prior normality is preferred, it also provides a more accurate lognormal relative-risk prior in for the 2x2 table format. For more compact representation in regression analyses, the prior data can be compressed into a single data record. The method is illustrated with historical data from a study of electronic foetal monitoring and neonatal death.

  15. Blood feeding patterns of mosquitoes: random or structured?

    Directory of Open Access Journals (Sweden)

    Nguyen Andy M

    2010-01-01

    Full Text Available Abstract Background The foraging behavior of blood-sucking arthropods is the defining biological event shaping the transmission cycle of vector-borne parasites. It is also a phenomenon that pertains to the realm of community ecology, since blood-feeding patterns of vectors can occur across a community of vertebrate hosts. Although great advances in knowledge of the genetic basis for blood-feeding choices have been reported for selected vector species, little is known about the role of community composition of vertebrate hosts in determining such patterns. Methods & Results Here, we present an analysis of feeding patterns of vectors across a variety of locations, looking at foraging patterns of communities of mosquitoes, across communities of hosts primarily comprised of mammals and birds. Using null models of species co-occurrence, which do not require ancillary information about host abundance, we found that blood-feeding patterns were aggregated in studies from multiple sites, but random in studies from a single site. This combination of results supports the idea that mosquito species in a community may rely primarily on host availability in a given landscape, and that contacts with specific hosts will be influenced more by the presence/absence of hosts than by innate mosquito choices. This observation stresses the importance of blood-feeding plasticity as a key trait explaining the emergence of many zoonotic mosquito transmitted diseases. Discussion From an epidemiological perspective our observations support the idea that phenomena promoting synchronization of vectors and hosts can promote the emergence of vector-borne zoonotic diseases, as suggested by observations on the linkages between deforestation and the emergence of several human diseases.

  16. Fast randomized approximate string matching with succinct hash data structures.

    Science.gov (United States)

    Policriti, Alberto; Prezza, Nicola

    2015-01-01

    The high throughput of modern NGS sequencers coupled with the huge sizes of genomes currently analysed, poses always higher algorithmic challenges to align short reads quickly and accurately against a reference sequence. A crucial, additional, requirement is that the data structures used should be light. The available modern solutions usually are a compromise between the mentioned constraints: in particular, indexes based on the Burrows-Wheeler transform offer reduced memory requirements at the price of lower sensitivity, while hash-based text indexes guarantee high sensitivity at the price of significant memory consumption. In this work we describe a technique that permits to attain the advantages granted by both classes of indexes. This is achieved using Hamming-aware hash functions--hash functions designed to search the entire Hamming sphere in reduced time--which are also homomorphisms on de Bruijn graphs. We show that, using this particular class of hash functions, the corresponding hash index can be represented in linear space introducing only a logarithmic slowdown (in the query length) for the lookup operation. We point out that our data structure reaches its goals without compressing its input: another positive feature, as in biological applications data is often very close to be un-compressible. The new data structure introduced in this work is called dB-hash and we show how its implementation--BW-ERNE--maintains the high sensitivity and speed of its (hash-based) predecessor ERNE, while drastically reducing space consumption. Extensive comparison experiments conducted with several popular alignment tools on both simulated and real NGS data, show, finally, that BW-ERNE is able to attain both the positive features of succinct data structures (that is, small space) and hash indexes (that is, sensitivity). In applications where space and speed are both a concern, standard methods often sacrifice accuracy to obtain competitive throughputs and memory footprints

  17. Structured Labels in Random Forests for Semantic Labelling and Object Detection.

    Science.gov (United States)

    Kontschieder, Peter; Bulò, Samuel Rota; Pelillo, Marcello; Bischof, Horst

    2014-10-01

    Ensembles of randomized decision trees, known as Random Forests, have become a valuable machine learning tool for addressing many computer vision problems. Despite their popularity, few works have tried to exploit contextual and structural information in random forests in order to improve their performance. In this paper, we propose a simple and effective way to integrate contextual information in random forests, which is typically reflected in the structured output space of complex problems like semantic image labelling. Our paper has several contributions: We show how random forests can be augmented with structured label information and be used to deliver structured low-level predictions. The learning task is carried out by employing a novel split function evaluation criterion that exploits the joint distribution observed in the structured label space. This allows the forest to learn typical label transitions between object classes and avoid locally implausible label configurations. We provide two approaches for integrating the structured output predictions obtained at a local level from the forest into a concise, global, semantic labelling. We integrate our new ideas also in the Hough-forest framework with the view of exploiting contextual information at the classification level to improve the performance on the task of object detection. Finally, we provide experimental evidence for the effectiveness of our approach on different tasks: Semantic image labelling on the challenging MSRCv2 and CamVid databases, reconstruction of occluded handwritten Chinese characters on the Kaist database and pedestrian detection on the TU Darmstadt databases.

  18. Dual resonant structure for energy harvesting from random vibration sources at low frequency

    Directory of Open Access Journals (Sweden)

    Shanshan Li

    2016-01-01

    Full Text Available We introduce a design with dual resonant structure which can harvest energy from random vibration sources at low frequency range. The dual resonant structure consists of two spring-mass subsystems with different frequency responses, which exhibit strong coupling and broad bandwidth when the two masses collide with each other. Experiments with piezoelectric elements show that the energy harvesting device with dual resonant structure can generate higher power output than the sum of the two separate devices from random vibration sources.

  19. Surface quasi periodic and random structures based on nanomotor lithography for light trapping

    Science.gov (United States)

    Golghasemi Sorkhabi, Sh.; Ahmadi-Kandjani, S.; Cousseau, F.; Loumaigne, M.; Zielinska, S.; Ortyl, E.; Barille, R.

    2017-07-01

    We compare the characteristics of two types of patterns obtained with two azopolymer materials: a Gaussian random pattern and a quasi-random grating pattern. The surface structurations have been obtained with a simple bottom-up technique, illuminating azopolymer thin films with a single laser beam. We demonstrate the interesting generated properties of these two surfaces. In particular, the surface with quasi-random gratings can address beam splitting for light coupling in different directions in an ultra-thin film. We use these two surfaces as a mold and replicate them on a transparent elastomeric material and demonstrate a very good light entrapment. We also show that the efficiency of light trapping is 20% better with the quasi-random gratings, than with the Gaussian random surface, and is close to 40%.

  20. [Multicentric prospective randomized and controlled study assessing effectiveness of intravaginal electrostimulation at home compared to usual care in female patients with urinary incontinence and prior perineal reeducation].

    Science.gov (United States)

    Lopès, P; Rimbault, F; Scheffler, M; André, C; Cappelletti, M-C; Marès, P

    2014-11-01

    In order to maintain the benefits of perineal reeducation, patients with stress urinary incontinence need to perform self-retraining exercises of the perineal muscles at home. The aim of this randomized prospective multicentric study is to assess the effectiveness of GYNEFFIK(®), a perineal electrostimulator, during this home-care phase. Two parallel groups of women with stress urinary incontinence (UI) or with mixed UI (composed predominantly of stress UI), improved by physiotherapy, have followed a self-reeducation program, either with electrostimulation sessions (GYNEFFIK(®) or home perineal electrostimulation [HPES] arm) or with usual care (UC) only, without electrostimulation. The comparison of the two groups was based on the rate of women in which the benefit of the initial perineal reeducation was maintained (defined as the ICIQ and Ditrovie scales' score not worsening) at 2, 4 and 6 months. A total of 161 patients were analyzed (76 in the HPES arm and 85 in the UC arm). The therapeutic benefit of the initial perineal reeducation at the last available measure (6 months for a wide majority of patients) was maintained in 81.6% in the HPES arm versus 62.4% in the UC arm (P=0.007). This significant difference reflects a significant improvement both in clinical symptomatology and in quality of life. ICIQ score was improved in 44% of patients of HPES arm while it was improved in 14% of patients of UC arm (P<0.001) and daily number of urine leakage decreased of 1.2 leakage in the HPES arm versus 0.1 leakage in UC arm (P<0.05). Likewise, improvement of quality of life was superior in the HPES arm (48% improvement of Ditrovie score versus 19% in the UC group ; P<0.05). Investigator global impression was more favorable in the HPES arm (clinical improvement in 83% of patients versus 68% in the UC arm). At the last measure (i.e. endpoint), the benefit of initial physiotherapy was considered maintained or improved in all patients of the HPES arm while it was reported

  1. Disrupted brain network functional dynamics and hyper-correlation of structural and functional connectome topology in patients with breast cancer prior to treatment.

    Science.gov (United States)

    Kesler, Shelli R; Adams, Marjorie; Packer, Melissa; Rao, Vikram; Henneghan, Ashley M; Blayney, Douglas W; Palesh, Oxana

    2017-03-01

    Several previous studies have demonstrated that cancer chemotherapy is associated with brain injury and cognitive dysfunction. However, evidence suggests that cancer pathogenesis alone may play a role, even in non-CNS cancers. Using a multimodal neuroimaging approach, we measured structural and functional connectome topology as well as functional network dynamics in newly diagnosed patients with breast cancer. Our study involved a novel, pretreatment assessment that occurred prior to the initiation of any cancer therapies, including surgery with anesthesia. We enrolled 74 patients with breast cancer age 29-65 and 50 frequency-matched healthy female controls who underwent anatomic and resting-state functional MRI as well as cognitive testing. Compared to controls, patients with breast cancer demonstrated significantly lower functional network dynamics (p = .046) and cognitive functioning (p cancer group also showed subtle alterations in structural local clustering and functional local clustering (p cancer may directly and/or indirectly affect the brain via mechanisms such as tumor-induced neurogenesis, inflammation, and/or vascular changes, for example. Our results also have broader implications concerning the importance of the balance between structural and functional connectome properties as a potential biomarker of general neurologic deficit.

  2. Studies on Structural and Resistive Switching Properties of Al/ZnO/Al Structured Resistive Random Access Memory

    Science.gov (United States)

    Li, Hongxia; Chen, Yiming; Wu, Xin; Xi, Junhua; Huang, Yanwei; Ji, Zhenguo

    Recently, resistive random access memory has been continuously investigated in order to replace the flash memory. In this paper, Al/ZnO/Al structured device was fabricated by magnetron sputtering and vacuum thermal evaporation. Systematic study has been conducted to explore the structural, morphological, and the resistive switching properties of ZnO films with Al metal as both bottom and top electrodes. The resistive switching mechanism of Al/ZnO/Al device was analyzed based on the above study.

  3. Special quasirandom structures for binary/ternary group IV random alloys

    KAUST Repository

    Chroneos, Alexander I.

    2010-06-01

    Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

  4. Perirhinal and hippocampal contributions to visual recognition memory can be distinguished from those of occipito-temporal structures based on conscious awareness of prior occurrence.

    Science.gov (United States)

    Danckert, S L; Gati, J S; Menon, R S; Köhler, S

    2007-01-01

    The ability of humans to distinguish consciously between new and previously encountered objects can be probed with visual recognition memory tasks that require explicit old-new discriminations. Medial temporal-lobe (MTL) lesions impair performance on such tasks. Within the MTL, both perirhinal cortex and the hippocampus have been implicated. Cognitive processes can also be affected by past object encounters in the absence of conscious recognition, as in repetition priming tasks. Past functional neuroimaging findings in healthy individuals suggest that even in tasks that require conscious recognition decisions for visual stimuli, posterior cortical structures in the ventral visual pathway distinguish between old and new objects at a nonconscious level. Conclusive evidence that differentiates the neural underpinnings of conscious from nonconscious processes in recognition memory, however, is still missing. In particular, functional magnetic resonance imaging (fMRI) findings for the MTL have been inconsistent towards this end. In the present fMRI study, we tested whether perirhinal and hippocampal contributions to recognition memory can be distinguished from those of occipito-temporal structures in the ventral visual pathway based on the participants' reported conscious awareness of prior occurrence. Images of objects with a large degree of feature overlap served as stimuli; they were selected to ensure an involvement of perirhinal cortex in the present recognition task, based on evidence from past lesion-based research. We found that both perirhinal cortex and occipito-temporal cortex showed a differential old-new response that reflected a repetition-related decrease in activity (i.e., new > old). Whereas in perirhinal cortex this decrease was observed with respect to whether subjects reported objects to be old or new, irrespective of the true item status, in occipito-temporal cortex it occurred in relation to whether objects were truly old or new, irrespective of

  5. Estimating 4D-CBCT from prior information and extremely limited angle projections using structural PCA and weighted free-form deformation for lung radiotherapy.

    Science.gov (United States)

    Harris, Wendy; Zhang, You; Yin, Fang-Fang; Ren, Lei

    2017-03-01

    To investigate the feasibility of using structural-based principal component analysis (PCA) motion-modeling and weighted free-form deformation to estimate on-board 4D-CBCT using prior information and extremely limited angle projections for potential 4D target verification of lung radiotherapy. A technique for lung 4D-CBCT reconstruction has been previously developed using a deformation field map (DFM)-based strategy. In the previous method, each phase of the 4D-CBCT was generated by deforming a prior CT volume. The DFM was solved by a motion model extracted by a global PCA and free-form deformation (GMM-FD) technique, using a data fidelity constraint and deformation energy minimization. In this study, a new structural PCA method was developed to build a structural motion model (SMM) by accounting for potential relative motion pattern changes between different anatomical structures from simulation to treatment. The motion model extracted from planning 4DCT was divided into two structures: tumor and body excluding tumor, and the parameters of both structures were optimized together. Weighted free-form deformation (WFD) was employed afterwards to introduce flexibility in adjusting the weightings of different structures in the data fidelity constraint based on clinical interests. XCAT (computerized patient model) simulation with a 30 mm diameter lesion was simulated with various anatomical and respiratory changes from planning 4D-CT to on-board volume to evaluate the method. The estimation accuracy was evaluated by the volume percent difference (VPD)/center-of-mass-shift (COMS) between lesions in the estimated and "ground-truth" on-board 4D-CBCT. Different on-board projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy. The method was also evaluated against three lung patients. The SMM-WFD method achieved substantially better accuracy than the GMM-FD method for CBCT estimation using extremely

  6. Coupling Neumann development and component mode synthesis methods for stochastic analysis of random structures

    Directory of Open Access Journals (Sweden)

    Driss Sarsri

    2014-05-01

    Full Text Available In this paper, we propose a method to calculate the first two moments (mean and variance of the structural dynamics response of a structure with uncertain variables and subjected to random excitation. For this, Newmark method is used to transform the equation of motion of the structure into a quasistatic equilibrium equation in the time domain. The Neumann development method was coupled with Monte Carlo simulations to calculate the statistical values of the random response. The use of modal synthesis methods can reduce the dimensions of the model before integration of the equation of motion. Numerical applications have been developed to highlight effectiveness of the method developed to analyze the stochastic response of large structures.

  7. Multisite Randomized Controlled Trial Examining Intelligent Tutoring of Structure Strategy for Fifth-Grade Readers

    Science.gov (United States)

    Wijekumar, Kausalai; Meyer, Bonnie J. F.; Lei, Pui-Wa; Lin, Yu-Chu; Johnson, Lori A.; Spielvogel, James A.; Shurmatz, Kathryn M.; Ray, Melissa; Cook, Michael

    2014-01-01

    This article reports on a large scale randomized controlled trial to study the efficacy of a web-based intelligent tutoring system for the structure strategy designed to improve content area reading comprehension. The research was conducted with 128 fifth-grade classrooms within 12 school districts in rural and suburban settings. Classrooms within…

  8. High Efficiency Computation of the Variances of Structural Evolutionary Random Responses

    Directory of Open Access Journals (Sweden)

    J.H. Lin

    2000-01-01

    Full Text Available For structures subjected to stationary or evolutionary white/colored random noise, their various response variances satisfy algebraic or differential Lyapunov equations. The solution of these Lyapunov equations used to be very difficult. A precise integration method is proposed in the present paper, which solves such Lyapunov equations accurately and very efficiently.

  9. Intervention for Verb Argument Structure in Children with Persistent SLI: A Randomized Control Trial

    Science.gov (United States)

    Ebbels, Susan H.; van der Lely, Heather K. J.; Dockrell, Julie E.

    2007-01-01

    Purpose: The authors aimed to establish whether 2 theoretically motivated interventions could improve use of verb argument structure in pupils with persistent specific language impairment (SLI). Method: Twenty-seven pupils with SLI (ages 11;0-16;1) participated in this randomized controlled trial with "blind" assessment. Participants were randomly…

  10. Patent foramen ovale closure with GORE HELEX or CARDIOFORM Septal Occluder vs. antiplatelet therapy for reduction of recurrent stroke or new brain infarct in patients with prior cryptogenic stroke: Design of the randomized Gore REDUCE Clinical Study.

    Science.gov (United States)

    Kasner, Scott E; Thomassen, Lars; Søndergaard, Lars; Rhodes, John F; Larsen, Coby C; Jacobson, Joth

    2017-12-01

    Rationale The utility of patent foramen ovale (PFO) closure for secondary prevention in patients with prior cryptogenic stroke is uncertain despite multiple randomized trials completed to date. Aims The Gore REDUCE Clinical Study (REDUCE) aims to establish superiority of patent foramen ovale closure in conjunction with antiplatelet therapy over antiplatelet therapy alone in reducing the risk of recurrent clinical ischemic stroke or new silent brain infarct in patients who have had a cryptogenic stroke. Methods and design This controlled, open-label trial randomized 664 subjects with cryptogenic stroke at 63 multinational sites in a 2:1 ratio to either antiplatelet therapy plus patent foramen ovale closure (with GORE® HELEX® Septal Occluder or GORE® CARDIOFORM Septal Occluder) or antiplatelet therapy alone. Subjects will be prospectively followed for up to five years. Neuroimaging is required for all subjects at baseline and at two years or study exit. Study outcomes The two co-primary endpoints for the study are freedom from recurrent clinical ischemic stroke through at least 24 months post-randomization and incidence of new brain infarct (defined as clinical ischemic stroke or silent brain infarct) through 24 months. The primary analyses are an unadjusted log-rank test and a binomial test of subject-based proportions, respectively, both on the intent-to-treat population, with adjustment for testing multiplicity. Discussion The REDUCE trial aims to target a patient population with truly cryptogenic strokes. Medical therapy is limited to antiplatelet agents in both arms thereby reducing confounding. The trial should determine whether patent foramen ovale closure with the Gore septal occluders is safe and more effective than medical therapy alone for the prevention of recurrent clinical ischemic stroke or new silent brain infarct; the neuroimaging data will provide an opportunity to further support the proof of concept. The main results are anticipated in 2017

  11. Analysis of subsystem randomness effects on the mid-frequency vibrations of built-up structures

    Science.gov (United States)

    Ji, Lin; Huang, Zhenyu

    2013-06-01

    The paper concerns the analysis of subsystem randomness effects on the mid-frequency vibration responses of built-up systems. The system model considered, in the first instance, is a long-wavelength finite element (FE) subsystem connected with a short-wavelength statistical energy analysis (SEA) subsystem via discrete couplings. The randomness effects of the SEA subsystem on both the displacement response of the FE subsystem and the energy response of the SEA subsystem are then investigated under the frame of the hybrid FE/SEA theory [P. Shorter, R. Langley, Vibro-acoustic analysis of complex systems, Journal of Sound and Vibration, 288 (2005) 669-700]. It is found that the subsystem randomness effects may be well indicated by a dimensionless parameter α, which is a function of the number of coupling points, the dynamic mismatch between the FE and SEA subsystems and the modal overlap factor of the SEA subsystem. The smaller the value of α is, the more insignificant the randomness effects are. As a result, a so-called "α-criterion" is derived which states that, if a built-up structure satisfies the condition of α≪1, the randomness effects of the SEA subsystem can be neglected. In this case, the SEA subsystem can be simply treated as an infinite (or semi-infinite as appropriate) structure regardless of its mode count being sufficiently high or not. Numerical examples are presented to illustrate the validity of the present theory.

  12. The Hidden Flow Structure and Metric Space of Network Embedding Algorithms Based on Random Walks.

    Science.gov (United States)

    Gu, Weiwei; Gong, Li; Lou, Xiaodan; Zhang, Jiang

    2017-10-13

    Network embedding which encodes all vertices in a network as a set of numerical vectors in accordance with it's local and global structures, has drawn widespread attention. Network embedding not only learns significant features of a network, such as the clustering and linking prediction but also learns the latent vector representation of the nodes which provides theoretical support for a variety of applications, such as visualization, link prediction, node classification, and recommendation. As the latest progress of the research, several algorithms based on random walks have been devised. Although those algorithms have drawn much attention for their high scores in learning efficiency and accuracy, there is still a lack of theoretical explanation, and the transparency of those algorithms has been doubted. Here, we propose an approach based on the open-flow network model to reveal the underlying flow structure and its hidden metric space of different random walk strategies on networks. We show that the essence of embedding based on random walks is the latent metric structure defined on the open-flow network. This not only deepens our understanding of random- walk-based embedding algorithms but also helps in finding new potential applications in network embedding.

  13. RESEARCH OF RELIABILITY OF A LONG-SPAN STRUCTURE EXPOSED TO RANDOM SEISMIC IMPACTS

    Directory of Open Access Journals (Sweden)

    Mondrus Vladimir L'vovich

    2012-10-01

    Full Text Available The article covers the problem of assessment of structural reliability in the course of random seismic impacts. The authors apply the Monte Carlo method and the method of canonical decomposition to generate accelerograms, and explicit time integration methods, by taking account of physical, geometrical and structural nonlinearities. The research results were subjected to statistical post-processing, and the analysis revealed that the structure demonstrated its high reliability. Therefore, the authors believe that the proposed approaches can be used to solve reliability problems that constitute variable processes.

  14. Nonlinear random responses of a structure parametrically coupled with liquid sloshing in a cylindrical tank

    Science.gov (United States)

    Ikeda, Takashi; Ibrahim, R. A.

    2005-06-01

    The nonlinear random interaction of an elastic structure with liquid sloshing dynamics in a cylindrical tank is investigated in the neighborhood of 2:1 internal resonance. Such internal resonance takes place when the natural frequency of the elastic structure is close to twice the natural frequency of the anti-symmetric sloshing mode (1,1). The excitation is generated from the response of a linear shaping filter subjected to a Gaussian white noise. The analytical model involves three sloshing modes (1,1), (0,1) and (2,1). The system response statistics and stability boundaries are numerically estimated using Monte Carlo simulation. The influence of the excitation center frequency, its bandwidth, and the liquid level on the system responses is studied. It is found that there is an irregular energy exchange between the structure and the liquid free surface motion when the center frequency is close to the structure natural frequency. Depending on the excitation power spectral density, the liquid free surface experiences zero motion, uncertain motion (intermittency), partially developed motion, and fully developed random motion. The structure response probability density function is almost Gaussian, while the liquid elevation deviates from normality. The unstable region, where the liquid motion occurs, becomes wider as the excitation intensity increases or as the bandwidth decreases. As the liquid depth or the structure spring stiffness decreases, the region of nonlinear interaction shrinks and is associated with a shift of the peak of the structure mean square response toward the left side of the frequency axis.

  15. Proposal of the Methodology for Analysing the Structural Relationship in the System of Random Process Using the Data Mining Methods

    National Research Council Canada - National Science Library

    German Michaľčonok; Michaela Horalová Kalinová; Martin Németh

    2014-01-01

    .... In this paper, we will approach the area of the random processes, present the process of structural analysis and select suitable circuit data mining methods applicable to the area of structural analysis...

  16. A general symplectic method for the response analysis of infinitely periodic structures subjected to random excitations

    Directory of Open Access Journals (Sweden)

    You-Wei Zhang

    Full Text Available A general symplectic method for the random response analysis of infinitely periodic structures subjected to stationary/non-stationary random excitations is developed using symplectic mathematics in conjunction with variable separation and the pseudo-excitation method (PEM. Starting from the equation of motion for a single loaded substructure, symplectic analysis is firstly used to eliminate the dependent degrees of the freedom through condensation. A Fourier expansion of the condensed equation of motion is then applied to separate the variables of time and wave number, thus enabling the necessary recurrence scheme to be developed. The random response is finally determined by implementing PEM. The proposed method is justified by comparison with results available in the literature and is then applied to a more complicated time-dependent coupled system.

  17. Impact of random safety analyses on structure, process and outcome indicators: multicentre study.

    Science.gov (United States)

    Bodí, María; Oliva, Iban; Martín, Maria Cruz; Gilavert, Maria Carmen; Muñoz, Carlos; Olona, Montserrat; Sirgo, Gonzalo

    2017-12-01

    To assess the impact of a real-time random safety tool on structure, process and outcome indicators. Prospective study conducted over a period of 12 months in two adult patient intensive care units. Safety rounds were conducted three days a week ascertaining 37 safety measures (grouped into 10 blocks). In each round, 50% of the patients and 50% of the measures were randomized. The impact of this safety tool was analysed on indicators of structure (safety culture, healthcare protocols), process (improvement proportion related to tool application, IPR) and outcome (mortality, average stay, rate of catheter-related bacteraemias and rate of ventilator-associated pneumonia, VAP). A total of 1214 patient-days were analysed. Structure indicators: the use of the safety tool was associated with an increase in the safety climate and the creation/modification of healthcare protocols (sedation/analgesia and weaning). Process indicators: Twelve of the 37 measures had an IPR > 10%; six showed a progressive decrease in the IPR over the study period. Nursing workloads and patient severity on the day of analysis were independently associated with a higher IPR in half of the blocks of variables. Outcome indicators: A significant decrease in the rate of VAP was observed. The real-time random safety tool improved the care process and adherence to clinical practice guidelines and was associated with an improvement in structure, process and outcome indicators.

  18. POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

    Directory of Open Access Journals (Sweden)

    Piet Stroeven

    2012-03-01

    Full Text Available Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements.  In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS, presented herein, and random node structuring (RaNoS provide such information. The latter method will be introduced in a next issue of IA&S.

  19. Managing Information Uncertainty in Wave Height Modeling for the Offshore Structural Analysis through Random Set

    Directory of Open Access Journals (Sweden)

    Keqin Yan

    2017-01-01

    Full Text Available This chapter presents a reliability study for an offshore jacket structure with emphasis on the features of nonconventional modeling. Firstly, a random set model is formulated for modeling the random waves in an ocean site. Then, a jacket structure is investigated in a pushover analysis to identify the critical wave direction and key structural elements. This is based on the ultimate base shear strength. The selected probabilistic models are adopted for the important structural members and the wave direction is specified in the weakest direction of the structure for a conservative safety analysis. The wave height model is processed in a P-box format when it is used in the numerical analysis. The models are applied to find the bounds of the failure probabilities for the jacket structure. The propagation of this wave model to the uncertainty in results is investigated in both an interval analysis and Monte Carlo simulation. The results are compared in context of information content and numerical accuracy. Further, the failure probability bounds are compared with the conventional probabilistic approach.

  20. Comparative effectiveness of natural and synthetic bone grafts in oral and maxillofacial surgery prior to insertion of dental implants: Systematic review and network meta-analysis of parallel and cluster randomized controlled trials.

    Science.gov (United States)

    Papageorgiou, Spyridon N; Papageorgiou, Panagiotis N; Deschner, James; Götz, Werner

    2016-05-01

    Bone grafts are often used to enhance bone volume/quality prior to implantation insertion. This systematic review compares the histomorphometric effectiveness of bone grafts in an evidence-based manner. Randomized clinical trials comparing histomorphometrically the % of newly-formed bone between two grafts were included. Risk of bias within and across studies was assessed with the Cochrane tool and the GRADE approach, respectively. Random-effects pairwise meta-analyses were conducted, followed by network meta-analysis, network meta-regression and sensitivity analyses. Four electronic databases were searched from inception to June 2015 without limitations. A total of 12 trials (5 parallel; 7 cluster) with a total of 231 patients (302 grafted sites) were included. No statistically significant differences were found in the % of new bone from pairwise comparisons between any two bone grafts. Treatment ranking based on the evidence network indicated that autografts presented the highest percentage of new bone, followed by synthetic grafts, xenografts, and allografts. No differences according to patient age, sex, healing time, membrane used or kind of surgical graft use were identified. Our confidence on pairwise comparisons was moderate to very low due to study limitations, inconsistency, and imprecision; our confidence on graft ranking was moderate due to study limitations. No significant differences were found in the percentage of new bone between any two grafts. Synthetic bone substitutes or xenologous bone grafts can be used as an alternative to autologous graft in order to overcome problems of additional surgeries or limited graft availability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Double-blind, randomized placebo controlled trial of fulvestrant compared with exemestane after prior nonsteroidal aromatase inhibitor therapy in postmenopausal women with hormone receptor-positive, advanced breast cancer: results from EFECT.

    Science.gov (United States)

    Chia, Stephen; Gradishar, William; Mauriac, Louis; Bines, Jose; Amant, Frederic; Federico, Miriam; Fein, Luis; Romieu, Gilles; Buzdar, Aman; Robertson, John F R; Brufsky, Adam; Possinger, Kurt; Rennie, Pamela; Sapunar, Francisco; Lowe, Elizabeth; Piccart, Martine

    2008-04-01

    The third-generation nonsteroidal aromatase inhibitors (AIs) are increasingly used as adjuvant and first-line advanced therapy for postmenopausal, hormone receptor-positive (HR+) breast cancer. Because many patients subsequently experience progression or relapse, it is important to identify agents with efficacy after AI failure. Evaluation of Faslodex versus Exemestane Clinical Trial (EFECT) is a randomized, double-blind, placebo controlled, multicenter phase III trial of fulvestrant versus exemestane in postmenopausal women with HR+ advanced breast cancer (ABC) progressing or recurring after nonsteroidal AI. The primary end point was time to progression (TTP). A fulvestrant loading-dose (LD) regimen was used: 500 mg intramuscularly on day 0, 250 mg on days 14, 28, and 250 mg every 28 days thereafter. Exemestane 25 mg orally was administered once daily. A total of 693 women were randomly assigned to fulvestrant (n = 351) or exemestane (n = 342). Approximately 60% of patients had received at least two prior endocrine therapies. Median TTP was 3.7 months in both groups (hazard ratio = 0.963; 95% CI, 0.819 to 1.133; P = .6531). The overall response rate (7.4% v 6.7%; P = .736) and clinical benefit rate (32.2% v 31.5%; P = .853) were similar between fulvestrant and exemestane respectively. Median duration of clinical benefit was 9.3 and 8.3 months, respectively. Both treatments were well tolerated, with no significant differences in the incidence of adverse events or quality of life. Pharmacokinetic data confirm that steady-state was reached within 1 month with the LD schedule of fulvestrant. Fulvestrant LD and exemestane are equally active and well-tolerated in a meaningful proportion of postmenopausal women with ABC who have experienced progression or recurrence during treatment with a nonsteroidal AI.

  2. Analysis of the structure of random packings of powder particles in laser additive technologies

    Directory of Open Access Journals (Sweden)

    Kovalev Oleg

    2017-01-01

    Full Text Available Under consideration are the peculiarities of the computer simulation of random packings of the particles involved in the laser additive technologies of selective laser melting and sintering of powders. The results of definition of random packings of monodisperse solid spheres are presented. Numerical analysis and structural investigations of their morphology are carried out. The peculiar character of the theoretical and computer models used for the analysis of particle packings in real powder media is understood. The technique of ray tracing is proposed for the description of laser radiation absorption and scattering in the layer of the stainless steel powder with the structure of the loose packing of mono-size spherical particles

  3. Random amino acid mutations and protein misfolding lead to Shannon limit in sequence-structure communication.

    Directory of Open Access Journals (Sweden)

    Andreas Martin Lisewski

    2008-09-01

    Full Text Available The transmission of genomic information from coding sequence to protein structure during protein synthesis is subject to stochastic errors. To analyze transmission limits in the presence of spurious errors, Shannon's noisy channel theorem is applied to a communication channel between amino acid sequences and their structures established from a large-scale statistical analysis of protein atomic coordinates. While Shannon's theorem confirms that in close to native conformations information is transmitted with limited error probability, additional random errors in sequence (amino acid substitutions and in structure (structural defects trigger a decrease in communication capacity toward a Shannon limit at 0.010 bits per amino acid symbol at which communication breaks down. In several controls, simulated error rates above a critical threshold and models of unfolded structures always produce capacities below this limiting value. Thus an essential biological system can be realistically modeled as a digital communication channel that is (a sensitive to random errors and (b restricted by a Shannon error limit. This forms a novel basis for predictions consistent with observed rates of defective ribosomal products during protein synthesis, and with the estimated excess of mutual information in protein contact potentials.

  4. Random amino acid mutations and protein misfolding lead to Shannon limit in sequence-structure communication.

    Science.gov (United States)

    Lisewski, Andreas Martin

    2008-09-01

    The transmission of genomic information from coding sequence to protein structure during protein synthesis is subject to stochastic errors. To analyze transmission limits in the presence of spurious errors, Shannon's noisy channel theorem is applied to a communication channel between amino acid sequences and their structures established from a large-scale statistical analysis of protein atomic coordinates. While Shannon's theorem confirms that in close to native conformations information is transmitted with limited error probability, additional random errors in sequence (amino acid substitutions) and in structure (structural defects) trigger a decrease in communication capacity toward a Shannon limit at 0.010 bits per amino acid symbol at which communication breaks down. In several controls, simulated error rates above a critical threshold and models of unfolded structures always produce capacities below this limiting value. Thus an essential biological system can be realistically modeled as a digital communication channel that is (a) sensitive to random errors and (b) restricted by a Shannon error limit. This forms a novel basis for predictions consistent with observed rates of defective ribosomal products during protein synthesis, and with the estimated excess of mutual information in protein contact potentials.

  5. Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065 (China); Ecole Normale Supérieure, CNRS-ENS-UPMC UMR 8640, 24 Rue Lhomond, Paris 75005 (France); Chen, Zhengfang [State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065 (China); Kang, Jian, E-mail: jiankang@scu.edu.cn [State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065 (China); Yang, Feng; Chen, Jinyao; Cao, Ya; Xiang, Ming [State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065 (China)

    2015-03-20

    Highlights: • We prepared β-PPR and studied its crystallization behavior with different melt structures. • We observed surprising synergetic effect between β-NA and the ordered structures. • We explored the nature of ordered structures by calculating the equilibrium temperature. - Abstract: Polypropylene random copolymer (PPR) is one of important polypropylene types for the application fields. However, due to the random copolymer chain configuration, it is difficult to obtain high proportion of β-phase even under the influence of β-nucleating agent (β-NA). In this study, the melt structure (namely, the content of ordered structures in the melt) of β-nucleated ethylene-copolymerized PPR (β-PPR) was controlled by tuning the fusion temperature (T{sub f}), and its impact on the crystallization and polymorphic behavior of β-PPR was investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), polarized optical microscopy (PLM) and scanning electronic microscopy (SEM). The result revealed that compared with the β-nucleated iPP homo-polymer, it is more difficult for β-PPR to form β-crystals; interestingly, when T{sub f} is in the temperature range of 162–173 °C, the ordered structures survived in melt exhibit high β-nucleation efficiency under the influence of β-NA, resulting in significant increase of β-phase proportion and evident variation of crystalline morphology, which is called the Ordered Structure Effect (OSE). Moreover, through investigating the self-nucleation behavior and equilibrium melting temperature of pure PPR (non-nucleated PPR), the physical nature of the lower and upper limiting T{sub f} temperatures for the occurrence of OSE in β-PPR was explored; the role of ethylene co-monomer in the occurrence of OSE was discussed.

  6. A Statistical Model Updating Method of Beam Structures with Random Parameters under Static Load

    Directory of Open Access Journals (Sweden)

    Zhifeng Wu

    2017-06-01

    Full Text Available This paper presents a new statistical model updating method of beam structures with random parameters under static load. The new updating method considers structural parameters and measurement errors to be random. To reduce the unmeasured degrees of freedom in the finite element model, a static condensation technique is used in this method. A statistical model updating equation with respect to element updated factors is established afterwards. The element updated factors are expanded as random multivariate power series. Using a high-order perturbation technique, the statistical model updating equation can be solved to obtain the coefficients of the power series expansions of the element updated factors. The results of two numerical examples show that for the solution of the statistical model updating equation, the accuracy of the proposed method agrees with that of the Monte Carlo simulation method very well. The static responses obtained by the updated finite element model coincide with the measured results very well. Finally, a series of static load tests of the concrete beam are conducted to testify the effectiveness of the proposed method.

  7. Monadic structures over an ordered universal random graph and finite automata

    Energy Technology Data Exchange (ETDEWEB)

    Dudakov, Sergey M [Tver' State University, Tver' (Russian Federation)

    2011-10-31

    We continue the investigation of the expressive power of the language of predicate logic for finite algebraic systems embedded in infinite systems. This investigation stems from papers of M. A. Taitslin, M. Benedikt and L. Libkin, among others. We study the properties of a finite monadic system which can be expressed by formulae if such a system is embedded in a random graph that is totally ordered in an arbitrary way. The Buechi representation is used to connect monadic structures and formal languages. It is shown that, if one restricts attention to formulae that are <-invariant in totally ordered random graphs, then these formulae correspond to finite automata. We show that =-invariant formulae expressing the properties of the embedded system itself can express only Boolean combinations of properties of the form 'the cardinality of an intersection of one-place predicates belongs to one of finitely many fixed finite or infinite arithmetic progressions'.

  8. Structural Analysis of Pressurized Small Diameter Lines in a Random Vibration Environment

    Science.gov (United States)

    Davis, Mark; Ridnour, Andrew; Brethen, Mark

    2011-01-01

    The pressurization and propellant feed lines for the Ares 1 Upper Stage Reaction and Roll Control Systems (ReCS and RoCS) were required to be in a high g-load random vibration flight environment. The lines connected the system components and were filled with both liquid hydrazine and gaseous helium. They are considered small and varied between one fourth to one inch in diameter. The random vibration of the lines was considered to be base excitation through the mating components and mounting hardware. It was found that reducing the amount of support structure for the lines added flexibility to the system and improved the line stresses from random vibration, but caused higher stresses from the static g-loads. The locations and number of brackets were optimized by analyzing the mode shapes of the lines causing high stresses. The use of brackets that only constrain motion in the direction of concern further reduced the stresses in the lines. Finite element analysis was used to perform the analysis. The lines were pre-stressed by temperature and internal pressure with fluid and insulation included as non-structural mass. Base excitation was added to the model using Power Spectral Density (PSD) data for the expected flight loads. The random vibration and static g-load cases were combined to obtain the total stress in the lines. This approach advances the state of the art in line analysis by using FEA to predict the stresses in the lines and to optimize the entire system based on the expected flight environment. Adding flexibility to lines has been used in piping system for temperature loads, but in flight environments flexibility has been limited for the static stresses. Adding flexibility to the system in a flight environment by reducing brackets has the benefit of reducing stresses and weight

  9. Immunogenicity and safety of an adjuvanted herpes zoster subunit candidate vaccine in adults ≥ 50 years of age with a prior history of herpes zoster: A phase III, non-randomized, open-label clinical trial.

    Science.gov (United States)

    Godeaux, Olivier; Kovac, Martina; Shu, Daniel; Grupping, Katrijn; Campora, Laura; Douha, Martine; Heineman, Thomas C; Lal, Himal

    2017-05-04

    This phase III, non-randomized, open-label, multi-center study (NCT01827839) evaluated the immunogenicity and safety of an adjuvanted recombinant subunit herpes zoster (HZ) vaccine (HZ/su) in adults aged ≥ 50 y with prior physician-documented history of HZ. Participants (stratified by age: 50-59, 60-69 and ≥ 70 y) received 2 doses of HZ/su 2 months apart and were followed-up for another 12 months. Anti-glycoprotein E (gE) antibodies were measured by enzyme-linked immunosorbent assay before vaccination and 1 month after the second dose (Month 3). Solicited local and general adverse events (AEs) were recorded for 7 d and unsolicited AEs for 30 d after each vaccination. Serious AEs were recorded until study end. The primary immunogenicity objective was met if the lower limit of the 95% confidence interval (CI) of the vaccine response rate (VRR), defined as a 4-fold increase in anti-gE over baseline, at Month 3 was ≥ 60%. 96 participants (32/age group) were enrolled. The primary immunogenicity objective was met, as the VRR at Month 3 was 90.2% (95% CI: 81.7-95.7). Geometric mean anti-gE antibody concentrations at Month 3 were similar across age groups. 77.9% and 71.6% of participants reported local and general solicited AEs, respectively. The most frequent solicited AEs were pain at injection site, fatigue, headache, myalgia and shivering. The HZ/su vaccine was immunogenic in adults aged ≥ 50 y with a physician-documented history of HZ, and no safety concerns were identified.

  10. Random Neighborhood Graphs as Models of Fracture Networks on Rocks: Structural and Dynamical Analysis

    CERN Document Server

    Estrada, Ernesto

    2016-01-01

    We propose a new model to account for the main structural characteristics of rock fracture networks (RFNs). The model is based on a generalization of the random neighborhood graphs to consider fractures embedded into rectangular spaces. We study a series of 29 real-world RFNs and find the best fit with the random rectangular neighborhood graphs (RRNGs) proposed here. We show that this model captures most of the structural characteristics of the RFNs and allows a distinction between small and more spherical rocks and large and more elongated ones. We use a diffusion equation on the graphs in order to model diffusive processes taking place through the channels of the RFNs. We find a small set of structural parameters that highly correlates with the average diffusion time in the RFNs. In particular, the second smallest eigenvalue of the Laplacian matrix is a good predictor of the average diffusion time on RFNs, showing a Pearson correlation coefficient larger than $0.99$ with the average diffusion time on RFNs. ...

  11. Electrostatic energy harvesting device with dual resonant structure for wideband random vibration sources at low frequency.

    Science.gov (United States)

    Zhang, Yulong; Wang, Tianyang; Zhang, Ai; Peng, Zhuoteng; Luo, Dan; Chen, Rui; Wang, Fei

    2016-12-01

    In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s2 at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.

  12. Solution NMR of MPS-1 reveals a random coil cytosolic domain structure.

    Directory of Open Access Journals (Sweden)

    Pan Li

    Full Text Available Caenorhabditis elegans MPS1 is a single transmembrane helical auxiliary subunit that co-localizes with the voltage-gated potassium channel KVS1 in the nematode nervous system. MPS-1 shares high homology with KCNE (potassium voltage-gated channel subfamily E member auxiliary subunits, and its cytosolic domain was reported to have a serine/threonine kinase activity that modulates KVS1 channel function via phosphorylation. In this study, NMR spectroscopy indicated that the full length and truncated MPS-1 cytosolic domain (134-256 in the presence or absence of n-dodecylphosphocholine detergent micelles adopted a highly flexible random coil secondary structure. In contrast, protein kinases usually adopt a stable folded conformation in order to implement substrate recognition and phosphoryl transfer. The highly flexible random coil secondary structure suggests that MPS-1 in the free state is unstructured but may require a substrate or binding partner to adopt stable structure required for serine/threonine kinase activity.

  13. Constructing priors in synesthesia.

    Science.gov (United States)

    van Leeuwen, Tessa M

    2014-01-01

    A new theoretical framework (PPSMC) applicable to synesthesia has been proposed, in which the discrepancy between the perceptual reality of (some) synesthetic concurrents and their subjective non-veridicality is being explained. The PPSMC framework stresses the relevance of the phenomenology of synesthesia for synesthesia research-and beyond. When describing the emergence and persistence of synesthetic concurrents under PPSMC, it is proposed that precise, high-confidence priors are crucial in synesthesia. I discuss the construction of priors in synesthesia.

  14. Generalized linear longitudinal mixed models with linear covariance structure and multiplicative random effects

    DEFF Research Database (Denmark)

    Holst, René; Jørgensen, Bent

    2015-01-01

    The paper proposes a versatile class of multiplicative generalized linear longitudinal mixed models (GLLMM) with additive dispersion components, based on explicit modelling of the covariance structure. The class incorporates a longitudinal structure into the random effects models and retains...... a marginal as well as a conditional interpretation. The estimation procedure is based on a computationally efficient quasi-score method for the regression parameters combined with a REML-like bias-corrected Pearson estimating function for the dispersion and correlation parameters. This avoids...... the multidimensional integral of the conventional GLMM likelihood and allows an extension of the robust empirical sandwich estimator for use with both association and regression parameters. The method is applied to a set of otholit data, used for age determination of fish....

  15. Quantization of Prior Probabilities for Hypothesis Testing

    OpenAIRE

    Varshney, Kush R.; Varshney, Lav R.

    2008-01-01

    Bayesian hypothesis testing is investigated when the prior probabilities of the hypotheses, taken as a random vector, are quantized. Nearest neighbor and centroid conditions are derived using mean Bayes risk error as a distortion measure for quantization. A high-resolution approximation to the distortion-rate function is also obtained. Human decision making in segregated populations is studied assuming Bayesian hypothesis testing with quantized priors.

  16. Numerical simulation of fibrous biomaterials with randomly distributed fiber network structure.

    Science.gov (United States)

    Jin, Tao; Stanciulescu, Ilinca

    2016-08-01

    This paper presents a computational framework to simulate the mechanical behavior of fibrous biomaterials with randomly distributed fiber networks. A random walk algorithm is implemented to generate the synthetic fiber network in 2D used in simulations. The embedded fiber approach is then adopted to model the fibers as embedded truss elements in the ground matrix, which is essentially equivalent to the affine fiber kinematics. The fiber-matrix interaction is partially considered in the sense that the two material components deform together, but no relative movement is considered. A variational approach is carried out to derive the element residual and stiffness matrices for finite element method (FEM), in which material and geometric nonlinearities are both included. Using a data structure proposed to record the network geometric information, the fiber network is directly incorporated into the FEM simulation without significantly increasing the computational cost. A mesh sensitivity analysis is conducted to show the influence of mesh size on various simulation results. The proposed method can be easily combined with Monte Carlo (MC) simulations to include the influence of the stochastic nature of the network and capture the material behavior in an average sense. The computational framework proposed in this work goes midway between homogenizing the fiber network into the surrounding matrix and accounting for the fully coupled fiber-matrix interaction at the segment length scale, and can be used to study the connection between the microscopic structure and the macro-mechanical behavior of fibrous biomaterials with a reasonable computational cost.

  17. Randomized Evaluation of the Effectiveness of a Structured Educational Program for Patients With Essential Hypertension.

    Science.gov (United States)

    Perl, Sabine; Niederl, Ella; Kos, Cornelia; Mrak, Peter; Ederer, Herbert; Rakovac, Ivo; Beck, Peter; Kraler, Elisabeth; Stoff, Ingrid; Klima, Gert; Pieske, Burkert M; Pieber, Thomas R; Zweiker, Robert

    2016-07-01

    Adherence to medication and lifestyle interventions are essential keys for the management of hypertension. In this respect, a structured educational program for hypertensive patients has got remarkable merits (herz.leben). In order to determine the isolated effect of participation in the educational program, neglecting the possible impact of more intense care, this prospective multicenter randomized controlled study was designed (NCT00453037). A total of 256 patients in 13 centers were enrolled and randomly assigned to 2 groups (G). G-I (n = 137) underwent the educational program immediately (T-0), G-II (n = 119) after 6 months (T-6). Follow-up visits were done after 6 (T-6) and 12 (T-12) months. Primary endpoint was a difference in office blood pressure (BP) at T-6, when only G-I had undergone the educational program. Patients' baseline characteristics were comparable. At T-6, systolic office and home BP were significantly lower in G-I compared to G-II: office BP systolic 139 (134-150) mm Hg vs. 150 (135-165) mm Hg (P educational program differences in BP disappeared. The results of this multicenter randomized controlled study provide significant evidence for benefit by participation in a structured educational program. Positive effects seem to be mediated by better adherence and life style changes due to higher levels of information and patient empowerment. Therefore, educational strategies should be considered as standard of care for hypertensive patients. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Arthur Prior and 'Now'

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2016-01-01

    ’s search led him through the work of Castañeda, and back to his own work on hybrid logic: the first made temporal reference philosophically respectable, the second made it technically feasible in a modal framework. With the aid of hybrid logic, Prior built a bridge from a two-dimensional UT calculus......On the 4th of December 1967, Hans Kamp sent his UCLA seminar notes on the logic of ‘now’ to Arthur N. Prior. Kamp’s two-dimensional analysis stimulated Prior to an intense burst of creativity in which he sought to integrate Kamp’s work into tense logic using a one-dimensional approach. Prior...... to a one-dimensional tense logic containing the ‘now’ operator J. Drawing on material from the Prior archive, and the paper “‘Now”’ that detailed Prior’s findings, we retell this story. We focus on Prior’s completeness conjecture for the hybrid system and the role played by temporal reference....

  19. Inferring visuomotor priors for sensorimotor learning.

    Directory of Open Access Journals (Sweden)

    Edward J A Turnham

    2011-03-01

    Full Text Available Sensorimotor learning has been shown to depend on both prior expectations and sensory evidence in a way that is consistent with Bayesian integration. Thus, prior beliefs play a key role during the learning process, especially when only ambiguous sensory information is available. Here we develop a novel technique to estimate the covariance structure of the prior over visuomotor transformations--the mapping between actual and visual location of the hand--during a learning task. Subjects performed reaching movements under multiple visuomotor transformations in which they received visual feedback of their hand position only at the end of the movement. After experiencing a particular transformation for one reach, subjects have insufficient information to determine the exact transformation, and so their second reach reflects a combination of their prior over visuomotor transformations and the sensory evidence from the first reach. We developed a Bayesian observer model in order to infer the covariance structure of the subjects' prior, which was found to give high probability to parameter settings consistent with visuomotor rotations. Therefore, although the set of visuomotor transformations experienced had little structure, the subjects had a strong tendency to interpret ambiguous sensory evidence as arising from rotation-like transformations. We then exposed the same subjects to a highly-structured set of visuomotor transformations, designed to be very different from the set of visuomotor rotations. During this exposure the prior was found to have changed significantly to have a covariance structure that no longer favored rotation-like transformations. In summary, we have developed a technique which can estimate the full covariance structure of a prior in a sensorimotor task and have shown that the prior over visuomotor transformations favor a rotation-like structure. Moreover, through experience of a novel task structure, participants can

  20. Non-random seasonal variation in the structure of a Mediterranean snake community

    Directory of Open Access Journals (Sweden)

    E. Filippi

    2007-05-01

    Full Text Available The community structure in relation to habitat type was studied in a Mediterranean community of snakes from Canale Monterano, central Italy. Habitat data for snakes were analysed both overall and divided by season, i.e. spring (April–June and summer (July–September. Community analyses were performed using null models (RA2 and RA3 algorithms and Monte Carlo simulations on habitat niche overlap estimates. Null models suggested that the community was assembled non-randomly (according to RA2 but not RA3, indicating that the generalist-specialist nature (the number of resource states, but not necessarily the types used by each species in the assemblage reduced ecological similarity. Similar results were reached also performing the same null model procedures on the spring datasets, whereas no structure emerged during summer either by RA2 or RA3 algorithms. In general, this study suggests that the community structure of snakes during spring may be shaped by the different eco-physiological needs of the various species (probably, the differential tolerance to cold and the consequent needs of finding suitable hibernacula, whereas the lack of structure during summer may be caused by the between-species similar foraging needs.

  1. Implications of structural genomics target selection strategies: Pfam5000, whole genome, and random approaches

    Energy Technology Data Exchange (ETDEWEB)

    Chandonia, John-Marc; Brenner, Steven E.

    2004-07-14

    The structural genomics project is an international effort to determine the three-dimensional shapes of all important biological macromolecules, with a primary focus on proteins. Target proteins should be selected according to a strategy which is medically and biologically relevant, of good value, and tractable. As an option to consider, we present the Pfam5000 strategy, which involves selecting the 5000 most important families from the Pfam database as sources for targets. We compare the Pfam5000 strategy to several other proposed strategies that would require similar numbers of targets. These include including complete solution of several small to moderately sized bacterial proteomes, partial coverage of the human proteome, and random selection of approximately 5000 targets from sequenced genomes. We measure the impact that successful implementation of these strategies would have upon structural interpretation of the proteins in Swiss-Prot, TrEMBL, and 131 complete proteomes (including 10 of eukaryotes) from the Proteome Analysis database at EBI. Solving the structures of proteins from the 5000 largest Pfam families would allow accurate fold assignment for approximately 68 percent of all prokaryotic proteins (covering 59 percent of residues) and 61 percent of eukaryotic proteins (40 percent of residues). More fine-grained coverage which would allow accurate modeling of these proteins would require an order of magnitude more targets. The Pfam5000 strategy may be modified in several ways, for example to focus on larger families, bacterial sequences, or eukaryotic sequences; as long as secondary consideration is given to large families within Pfam, coverage results vary only slightly. In contrast, focusing structural genomics on a single tractable genome would have only a limited impact in structural knowledge of other proteomes: a significant fraction (about 30-40 percent of the proteins, and 40-60 percent of the residues) of each proteome is classified in small

  2. Effects of hormone therapy on brain structure: A randomized controlled trial.

    Science.gov (United States)

    Kantarci, Kejal; Tosakulwong, Nirubol; Lesnick, Timothy G; Zuk, Samantha M; Gunter, Jeffrey L; Gleason, Carey E; Wharton, Whitney; Dowling, N Maritza; Vemuri, Prashanthi; Senjem, Matthew L; Shuster, Lynne T; Bailey, Kent R; Rocca, Walter A; Jack, Clifford R; Asthana, Sanjay; Miller, Virginia M

    2016-08-30

    To investigate the effects of hormone therapy on brain structure in a randomized, double-blinded, placebo-controlled trial in recently postmenopausal women. Participants (aged 42-56 years, within 5-36 months past menopause) in the Kronos Early Estrogen Prevention Study were randomized to (1) 0.45 mg/d oral conjugated equine estrogens (CEE), (2) 50 μg/d transdermal 17β-estradiol, or (3) placebo pills and patch for 48 months. Oral progesterone (200 mg/d) was given to active treatment groups for 12 days each month. MRI and cognitive testing were performed in a subset of participants at baseline, and at 18, 36, and 48 months of randomization (n = 95). Changes in whole brain, ventricular, and white matter hyperintensity volumes, and in global cognitive function, were measured. Higher rates of ventricular expansion were observed in both the CEE and the 17β-estradiol groups compared to placebo; however, the difference was significant only in the CEE group (p = 0.01). Rates of ventricular expansion correlated with rates of decrease in brain volume (r = -0.58; p ≤ 0.001) and with rates of increase in white matter hyperintensity volume (r = 0.27; p = 0.01) after adjusting for age. The changes were not different between the CEE and 17β-estradiol groups for any of the MRI measures. The change in global cognitive function was not different across the groups. Ventricular volumes increased to a greater extent in recently menopausal women who received CEE compared to placebo but without changes in cognitive performance. Because the sample size was small and the follow-up limited to 4 years, the findings should be interpreted with caution and need confirmation. This study provides Class I evidence that brain ventricular volume increased to a greater extent in recently menopausal women who received oral CEE compared to placebo. © 2016 American Academy of Neurology.

  3. Robotic objective structured assessment of technical skills: a randomized multicenter dry laboratory training pilot study.

    Science.gov (United States)

    Tarr, Megan Elizabeth; Rivard, Colleen; Petzel, Amy E; Summers, Sondra; Mueller, Elizabeth R; Rickey, Leslie M; Denman, Mary A; Harders, Regina; Durazo-Arvizu, Ramon; Kenton, Kimberly

    2014-01-01

    The goal of this study was to determine if a robotic dry laboratory curriculum for gynecology and urology residents improved their basic robotic skills. After the institution-specific institutional review board approval or exemption, 165 residents from 8 gynecology and/or urology programs were enrolled. Residents underwent standardized robotic orientation followed by dry laboratory testing on 4 unique robotic tasks. Residents were block randomized by program to unstructured or structured training programs. Regardless of group, residents were expected to practice for 15 minutes twice monthly over 7 months. Errors, time to completion, and objective structured assessment of technical skills global rating scores were recorded for each task before and after the training period. Statistics were calculated using the Student t tests, Pearson correlation, and analysis of variance with STATA systems (version 11.2). A total of 99 residents completed both the pretraining and posttraining testing. A mean of 4 (range, 0-15) 15-minute training sessions per resident was self-reported. The structured group had faster posttraining times on the transection task, although the unstructured group had higher posttraining scores on the knot-tying task. Overall, the residents' robotic skills improved after participating in a dry laboratory curriculum; however, robotic availability, duty hour restrictions, and clinical responsibilities limit the curriculum implementation.

  4. Network motif identification and structure detection with exponential random graph models

    Directory of Open Access Journals (Sweden)

    Munni Begum

    2014-12-01

    Full Text Available Local regulatory motifs are identified in the transcription regulatory network of the most studied model organism Escherichia coli (E. coli through graphical models. Network motifs are small structures in a network that appear more frequently than expected by chance alone. We apply social network methodologies such as p* models, also known as Exponential Random Graph Models (ERGMs, to identify statistically significant network motifs. In particular, we generate directed graphical models that can be applied to study interaction networks in a broad range of databases. The Markov Chain Monte Carlo (MCMC computational algorithms are implemented to obtain the estimates of model parameters to the corresponding network statistics. A variety of ERGMs are fitted to identify statistically significant network motifs in transcription regulatory networks of E. coli. A total of nine ERGMs are fitted to study the transcription factor - transcription factor interactions and eleven ERGMs are fitted for the transcription factor-operon interactions. For both of these interaction networks, arc (a directed edge in a directed network and k-istar (or incoming star structures, for values of k between 2 and 10, are found to be statistically significant local structures or network motifs. The goodness of fit statistics are provided to determine the quality of these models.

  5. Analysis of tree stand horizontal structure using random point field methods

    Directory of Open Access Journals (Sweden)

    O. P. Sekretenko

    2015-06-01

    Full Text Available This paper uses the model approach to analyze the horizontal structure of forest stands. The main types of models of random point fields and statistical procedures that can be used to analyze spatial patterns of trees of uneven and even-aged stands are described. We show how modern methods of spatial statistics can be used to address one of the objectives of forestry – to clarify the laws of natural thinning of forest stand and the corresponding changes in its spatial structure over time. Studying natural forest thinning, we describe the consecutive stages of modeling: selection of the appropriate parametric model, parameter estimation and generation of point patterns in accordance with the selected model, the selection of statistical functions to describe the horizontal structure of forest stands and testing of statistical hypotheses. We show the possibilities of a specialized software package, spatstat, which is designed to meet the challenges of spatial statistics and provides software support for modern methods of analysis of spatial data. We show that a model of stand thinning that does not consider inter-tree interaction can project the size distribution of the trees properly, but the spatial pattern of the modeled stand is not quite consistent with observed data. Using data of three even-aged pine forest stands of 25, 55, and 90-years old, we demonstrate that the spatial point process models are useful for combining measurements in the forest stands of different ages to study the forest stand natural thinning.

  6. The thermodynamic and structural properties of metallocenes-type random ethylene copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Simanke, Adriane G.; Mauler, Raquel S.; Galland, Griselda B. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Quimica]. E-mail: asimanke@portoweb.com.br; Alamo, Rufina G. [Florida State Univ., Tallahassee, FL (UNited States). College of Engineering. Dept. of Chemical Engineering]. E-mail: alamo@eng.fsu.edu

    2001-07-01

    The properties of a series of random ethylene copolymers prepared with the metallocenes catalytic system rac-Et[Ind]{sub 2} ZrCl{sub 2}/MAO were studied for a large variety of comonomer types. These include the classical 1-alkene type with length up to 10 carbons and those of the cyclic type such as cyclopentadiene and dicyclopentadiene. Under rapid crystallization, the melting temperatures of the newly synthesized copolymers followed the relation of model random copolymers indicating a behavior that conforms to that predicted by Flory's phase equilibrium theory. The molar entropy of fusion is not significantly altered by the comonomer type including the dicyclopentadiene type. All types of comonomers studied showed, for a fixed comonomer content, the same change in properties during annealing, except the ethylene 1-butenes. These latter copolymers and the hydrogenated poly butadiene showed a faster rate of change in thermal properties. This is consistent with a higher molecular diffusion for the butene comonomer than for the rest of comonomers analyzed. The properties of the inter lamellar region were also studied as a function of comonomer type and content following the variation of the amorphous halo extracted from the WAXS diffractograms. The observed systematic decrease in the peak scattering angle with increasing comonomer content indicates a variation of the intermolecular liquid structure. (author)

  7. Lifetime Reliability Estimate and Extreme Permanent Deformations of Randomly Excited Elasto-Plastic Structures

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1983-01-01

    A method is presented for life-time reliability' estimates of randomly excited yielding systems, assuming the structure to be safe, when the plastic deformations are confined below certain limits. The accumulated plastic deformations during any single significant loading history are considered...... to be the outcome of identically distributed, independent stochastic variables,for which a model is suggested. Further assuming the interarrival times of the elementary loading histories to be specified by a Poisson process, and the duration of these to be small compared to the designed life-time, the accumulated...... plastic deformation during several loadings can be modelled as a filtered Poisson process. Using the Markov property of this quantity the considered first-passage problem as well as the related extreme distribution problems are then solved numerically, and the results are compared to simulation studies....

  8. Structuring communication relationships for interprofessional teamwork (SCRIPT: a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Kenaszchuk Chris

    2007-09-01

    Full Text Available Abstract Background Despite a burgeoning interest in using interprofessional approaches to promote effective collaboration in health care, systematic reviews find scant evidence of benefit. This protocol describes the first cluster randomized controlled trial (RCT to design and evaluate an intervention intended to improve interprofessional collaborative communication and patient-centred care. Objectives The objective is to evaluate the effects of a four-component, hospital-based staff communication protocol designed to promote collaborative communication between healthcare professionals and enhance patient-centred care. Methods The study is a multi-centre mixed-methods cluster randomized controlled trial involving twenty clinical teaching teams (CTTs in general internal medicine (GIM divisions of five Toronto tertiary-care hospitals. CTTs will be randomly assigned either to receive an intervention designed to improve interprofessional collaborative communication, or to continue usual communication practices. Non-participant naturalistic observation, shadowing, and semi-structured, qualitative interviews were conducted to explore existing patterns of interprofessional collaboration in the CTTs, and to support intervention development. Interviews and shadowing will continue during intervention delivery in order to document interactions between the intervention settings and adopters, and changes in interprofessional communication. The primary outcome is the rate of unplanned hospital readmission. Secondary outcomes are length of stay (LOS; adherence to evidence-based prescription drug therapy; patients' satisfaction with care; self-report surveys of CTT staff perceptions of interprofessional collaboration; and frequency of calls to paging devices. Outcomes will be compared on an intention-to-treat basis using adjustment methods appropriate for data from a cluster randomized design. Discussion Pre-intervention qualitative analysis revealed that a

  9. A Deep-Structured Conditional Random Field Model for Object Silhouette Tracking.

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Shafiee

    Full Text Available In this work, we introduce a deep-structured conditional random field (DS-CRF model for the purpose of state-based object silhouette tracking. The proposed DS-CRF model consists of a series of state layers, where each state layer spatially characterizes the object silhouette at a particular point in time. The interactions between adjacent state layers are established by inter-layer connectivity dynamically determined based on inter-frame optical flow. By incorporate both spatial and temporal context in a dynamic fashion within such a deep-structured probabilistic graphical model, the proposed DS-CRF model allows us to develop a framework that can accurately and efficiently track object silhouettes that can change greatly over time, as well as under different situations such as occlusion and multiple targets within the scene. Experiment results using video surveillance datasets containing different scenarios such as occlusion and multiple targets showed that the proposed DS-CRF approach provides strong object silhouette tracking performance when compared to baseline methods such as mean-shift tracking, as well as state-of-the-art methods such as context tracking and boosted particle filtering.

  10. On the Response of a Nonlinear Structure to High Kurtosis Non-Gaussian Random Loadings

    Science.gov (United States)

    Rizzi, Stephen A.; Przekop, Adam; Turner, Travis L.

    2011-01-01

    This paper is a follow-on to recent work by the authors in which the response and high-cycle fatigue of a nonlinear structure subject to non-Gaussian loadings was found to vary markedly depending on the nature of the loading. There it was found that a non-Gaussian loading having a steady rate of short-duration, high-excursion peaks produced essentially the same response as would have been incurred by a Gaussian loading. In contrast, a non-Gaussian loading having the same kurtosis, but with bursts of high-excursion peaks was found to elicit a much greater response. This work is meant to answer the question of when consideration of a loading probability distribution other than Gaussian is important. The approach entailed nonlinear numerical simulation of a beam structure under Gaussian and non-Gaussian random excitations. Whether the structure responded in a Gaussian or non-Gaussian manner was determined by adherence to, or violations of, the Central Limit Theorem. Over a practical range of damping, it was found that the linear response to a non-Gaussian loading was Gaussian when the period of the system impulse response is much greater than the rate of peaks in the loading. Lower damping reduced the kurtosis, but only when the linear response was non-Gaussian. In the nonlinear regime, the response was found to be non-Gaussian for all loadings. The effect of a spring-hardening type of nonlinearity was found to limit extreme values and thereby lower the kurtosis relative to the linear response regime. In this case, lower damping gave rise to greater nonlinearity, resulting in lower kurtosis than a higher level of damping.

  11. Validation of the k-filtering technique for a signal composed of random-phase plane waves and non-random coherent structures

    Directory of Open Access Journals (Sweden)

    O. W. Roberts

    2014-12-01

    Full Text Available Recent observations of astrophysical magnetic fields have shown the presence of fluctuations being wave-like (propagating in the plasma frame and those described as being structure-like (advected by the plasma bulk velocity. Typically with single-spacecraft missions it is impossible to differentiate between these two fluctuations, due to the inherent spatio-temporal ambiguity associated with a single point measurement. However missions such as Cluster which contain multiple spacecraft have allowed for temporal and spatial changes to be resolved, using techniques such as k filtering. While this technique does not assume Taylor's hypothesis it requires both weak stationarity of the time series and that the fluctuations can be described by a superposition of plane waves with random phases. In this paper we test whether the method can cope with a synthetic signal which is composed of a combination of non-random-phase coherent structures with a mean radius d and a mean separation λ, as well as plane waves with random phase.

  12. Prior indigenous technological species

    Science.gov (United States)

    Wright, Jason T.

    2018-01-01

    One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere the solar system. Implicit in much of this work is that we are looking for microbial or, at best, unintelligent life, even though technological artefacts might be much easier to find. Search for Extraterrestrial Intelligence (SETI) work on searches for alien artefacts in the solar system typically presumes that such artefacts would be of extrasolar origin, even though life is known to have existed in the solar system, on Earth, for eons. But if a prior technological, perhaps spacefaring, species ever arose in the solar system, it might have produced artefacts or other technosignatures that have survived to present day, meaning solar system artefact SETI provides a potential path to resolving astrobiology's question. Here, I discuss the origins and possible locations for technosignatures of such a prior indigenous technological species, which might have arisen on ancient Earth or another body, such as a pre-greenhouse Venus or a wet Mars. In the case of Venus, the arrival of its global greenhouse and potential resurfacing might have erased all evidence of its existence on the Venusian surface. In the case of Earth, erosion and, ultimately, plate tectonics may have erased most such evidence if the species lived Gyr ago. Remaining indigenous technosignatures might be expected to be extremely old, limiting the places they might still be found to beneath the surfaces of Mars and the Moon, or in the outer solar system.

  13. Dynamic reorganization of chromatin structure and selective DNA demethylation prior to stable enhancer complex formation during differentiation of primary hematopoietic cells in vitro.

    Science.gov (United States)

    Tagoh, Hiromi; Melnik, Svitlana; Lefevre, Pascal; Chong, Suyinn; Riggs, Arthur D; Bonifer, Constanze

    2004-04-15

    In order to gain insights in the true molecular mechanisms involved in cell fate decisions, it is important to study the molecular details of gene activation where such decisions occur, which is at the level of the chromatin structure of individual genes. In the study presented here we addressed this issue and examined the dynamic development of an active chromatin structure at the chicken lysozyme locus during the differentiation of primary myeloid cells from transgenic mouse bone marrow. Using in vivo footprinting we found that stable enhancer complex assembly and high-level gene expression are late events in cell differentiation. However, even before the onset of gene expression and stable transcription factor binding, specific chromatin alterations are observed. This includes changes in DNA topology and the selective demethylation of CpG dinucleotides located in the cores of critical transcription factor binding sites, but not in flanking DNA. These results firmly support the idea that epigenetic programs guiding blood cell differentiation are engraved into the chromatin of lineage-specific genes and that such chromatin changes are implemented before cell lineage specification.

  14. Tools to reduce first year nursing students' anxiety levels prior to undergoing objective structured clinical assessment (OSCA) and how this impacts on the student's experience of their first clinical placement.

    Science.gov (United States)

    Stunden, Annette; Halcomb, Elizabeth; Jefferies, Diana

    2015-09-01

    One form of assessment that tests students' theoretical skills and confidence in their clinical practice is known as the Objective Structured Clinical Assessment (OSCA). Traditionally it was first launched from medical education, and is now being incorporated by other disciplines, such as nursing. This review seeks to present the best available evidence into strategies that help reduce first year nursing students' anxiety levels prior to undergoing OSCA and clinical placement. A systematic literature search was performed using Medline and CINAHL. This review considered any English language original research published between 2005 and 2013. A literature search located 117 articles. Eight articles were identified as meeting the inclusion in criteria. Majority of studies reported simulation session prior to the OSCA increased students confidence and reduced their anxiety levels. This resulted in students' reporting that they valued the OSCA as a worthwhile assessment. However there were four major themes: that students were anxious about attending the OSCA; that adequate preparation was seen as a coping strategy; that simulation was a further cause for anxiety; and that the simulation experience could also be used as an OSCA tool. Students who have been exposed to simulation scenarios before the OSCA are able to cope much better during the OSCA. Therefore, it is highly recommended to incorporate simulation scenarios into the nursing curricula for first year nursing students' clinical units to help reduce their anxiety levels prior to OCSA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Non-random correlation structures and dimensionality reduction in multivariate climate data

    Science.gov (United States)

    Vejmelka, Martin; Pokorná, Lucie; Hlinka, Jaroslav; Hartman, David; Jajcay, Nikola; Paluš, Milan

    2015-05-01

    It is well established that the global climate is a complex phenomenon with dynamics driven by the interaction of a multitude of identifiable but intertwined subsystems. The identification, at some level, of these subsystems is an important step towards understanding climate dynamics. We present a method to determine the number of principal components representing non-random correlation structures in climate data, or components that cannot be generated by a surrogate model of independent stochastic processes replicating the auto-correlation structure of each time series. The purpose of the method is to automatically reduce the dimensionality of large climate datasets into spatially localised components suitable for further interpretation or, for example, for use as nodes in a complex network analysis of large-scale climate dynamics. We apply the method to two 2.5° resolution NCEP/NCAR reanalysis global datasets of monthly means: the sea level pressure (SLP) and the surface air temperature (SAT), and extract 60 components explaining 87 % variance and 68 components explaining 72 % variance, respectively. The obtained components are in agreement with previous results in that they recover many well-known climate modes previously identified using other approaches including regionally constrained principal component analysis. Selected SLP components are discussed in more detail with respect to their correlation with important climate indices and their relationship to other SLP and SAT components. Finally, we consider a subset of the obtained components that have not yet been explicitly identified by other authors but seem plausible in the context of regional climate observations discussed in literature.

  16. Effect of periodontal therapy on arterial structure and function among aboriginal australians: a randomized, controlled trial.

    Science.gov (United States)

    Kapellas, Kostas; Maple-Brown, Louise J; Jamieson, Lisa M; Do, Loc G; O'Dea, Kerin; Brown, Alex; Cai, Tommy Y; Anstey, Nicholas M; Sullivan, David R; Wang, Hao; Celermajer, David S; Slade, Gary D; Skilton, Michael R

    2014-10-01

    Observational studies and nonrandomized trials support an association between periodontal disease and atherosclerotic vascular disease. Both diseases occur frequently in Aboriginal Australians. We hypothesized that nonsurgical periodontal therapy would improve measures of arterial function and structure that are subclinical indicators of atherosclerotic vascular disease. This parallel-group, randomized, open label clinical trial enrolled 273 Aboriginal Australians aged ≥18 years with periodontitis. Intervention participants received full-mouth periodontal scaling during a single visit, whereas controls received no treatment. Prespecified primary end points measured 12-month change in carotid intima-media thickness, an indicator of arterial structure, and 3- and 12-month change in pulse wave velocity, an indicator of arterial function. ANCOVA used complete case data to evaluate treatment group differences. End points could be calculated for 169 participants with follow-up data at 3 months and 168 participants at 12 months. Intima-media thickness decreased significantly after 12 months in the intervention group (mean reduction=-0.023 [95% confidence interval {CI}, -0.038 to -0.008] mm) but not in the control group (mean increase=0.002 [95% CI, -0.017 to 0.022] mm). The difference in intima-media thickness change between treatment groups was statistically significant (-0.026 [95% CI, -0.048 to -0.003] mm; P=0.03). In contrast, there were no significant differences between treatment groups in pulse wave velocity at 3 months (mean difference, 0.06 [95% CI, -0.17 to 0.29] m/s; P=0.594) or 12 months (mean difference, 0.21 [95% CI, -0.01 to 0.43] m/s; P=0.062). Periodontal therapy reduced subclinical arterial thickness but not function in Aboriginal Australians with periodontal disease, suggesting periodontal disease and atherosclerosis are significantly associated. © 2014 American Heart Association, Inc.

  17. Modeling and simulation of electronic structure, material interface and random doping in nano electronic devices

    Science.gov (United States)

    Chen, Duan; Wei, Guo-Wei

    2010-01-01

    The miniaturization of nano-scale electronic devices, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. Modeling and simulation of this class of problems have emerged as an important topic in applied and computational mathematics. This work presents mathematical models and computational algorithms for the simulation of nano-scale MOSFETs. We introduce a unified two-scale energy functional to describe the electrons and the continuum electrostatic potential of the nano-electronic device. This framework enables us to put microscopic and macroscopic descriptions in an equal footing at nano scale. By optimization of the energy functional, we derive consistently-coupled Poisson-Kohn-Sham equations. Additionally, layered structures are crucial to the electrostatic and transport properties of nano transistors. A material interface model is proposed for more accurate description of the electrostatics governed by the Poisson equation. Finally, a new individual dopant model that utilizes the Dirac delta function is proposed to understand the random doping effect in nano electronic devices. Two mathematical algorithms, the matched interface and boundary (MIB) method and the Dirichlet-to-Neumann mapping (DNM) technique, are introduced to improve the computational efficiency of nano-device simulations. Electronic structures are computed via subband decomposition and the transport properties, such as the I-V curves and electron density, are evaluated via the non-equilibrium Green's functions (NEGF) formalism. Two distinct device configurations, a double-gate MOSFET and a four-gate MOSFET, are considered in our three-dimensional numerical simulations. For these devices, the current fluctuation and voltage threshold lowering effect induced by the discrete dopant model are explored. Numerical convergence

  18. Structured operative reporting: a randomized trial using dictation templates to improve operative reporting.

    Science.gov (United States)

    Gillman, Lawrence M; Vergis, Ashley; Park, Jason; Minor, Sam; Taylor, Mark

    2010-06-01

    Few studies have addressed the quality of dictated operative reports (ORs). This study documents changes in resident dictation after the introduction of a standardized OR template. Twenty residents dictated an OR based on a surgical procedure video. Residents were randomized to receive an OR template or no intervention. Residents dictated another report 3 months later. Outcomes measures were dictation quality using a previously validated tool and resident comfort with dictation. There was no overall difference in quality in the intervention group as measured by the Structured Assessment Form (SAF) (28.6 vs 30.0, P = .36) and Global Quality Ratings Scale (GQRS) (21.7 vs 21.8, P = .96). However, junior resident subgroup analysis revealed an improvement in the intervention group on both the SAF (23.2 vs 28.3, P = .02) and GQRS (17.1 vs 20.4, P = .02). Subjective comfort level improved in the intervention group (P = .02). The operative dictation template can significantly improve resident comfort level with dictation and has the potential to improve the quality of junior resident dictations. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Bi-resonant structure with piezoelectric PVDF films for energy harvesting from random vibration sources at low frequency

    DEFF Research Database (Denmark)

    Liang, Shanshan; Crovetto, Andrea; Peng, Zhuoteng

    2016-01-01

    and experiments with piezoelectric elements show that the energy harvesting device with the bi-resonant structure can generate higher power output than that of the sum of the two separate devices from random vibration sources at low frequency, and hence significantly improves the vibration-to- electricity...

  20. Genetic diversity and structure of Schistosoma japonicum within two marshland villages of Anhui, China, prior to schistosome transmission control and elimination.

    Science.gov (United States)

    Ding, Huan; Lu, Da-Bing; Gao, Yu-Meng; Deng, Yao; Li, Ying

    2017-02-01

    Schistosomiasis is caused by the genus Schistosoma and affected more than 250 million people worldwide. Schistosoma japonicum was once seriously endemic in China and nearly 60 years of efforts has seen great success in disease control. However, due to its zoonotic nature and complex life cycle, the schistosomiasis transmission control and final elimination would require, besides an intersectoral approach, deep understanding of population genetics of the parasite. We therefore performed a snail survey in two marshland villages of Anhui province of China and collected S. japonicum cercariae from infected snails. By using the recent developed microsatellite panel comprising seven loci, we genotyped the sampled parasites and analyzed the population genetic diversity and structure. The results showed much lower infection prevalence of S. japonicum in snails and low infected snail density in either marshland village. Through population genetic analyses, a considerable genetic diversity of parasites was revealed, whereas a small number of clusters were inferred and the sign of bottleneck effect was detected in each village. For the first time in S. japonicum in two villages, we provided estimates of effective population sizes with two different approaches. The results indicated that the parasite in two villages could eventually be eradicated with the ongoing integral control measures, but with potential risk of reinvasion of immigrant parasites through the Yangtze River. Such would be of great importance in assessment of the effects of ongoing control measures and prediction of the transmission capability for S. japonicum, thus guiding decisions on the choice of further control work.

  1. Intranasal sufentanil/midazolam versus ketamine/midazolam for analgesia/sedation in the pediatric population prior to undergoing multiple dental extractions under general anesthesia: a prospective, double-blind, randomized comparison.

    OpenAIRE

    Roelofse, J. A.; Shipton, E. A.; de la Harpe, C. J.; Blignaut, R. J.

    2004-01-01

    This article details a double-blind, randomized study evaluating the efficacy and safety of intranasal sufentanil and intranasal midazolam (S/M) when compared with intranasal ketamine and intranasal midazolam (K/M) for sedation and analgesia in pediatric patients undergoing dental surgery. Fifty healthy ASA status 1 children aged 5-7 years, weighing 15-20 kg, and having 6 or more teeth extracted, were randomly allocated to 2 groups of 25 patients each (n = 50). In the S/M group, 25 children r...

  2. The prior statistics of object colors

    NARCIS (Netherlands)

    Koenderink, J.J.

    2010-01-01

    The prior statistics of object colors is of much interest because extensive statistical investigations of reflectance spectra reveal highly non-uniform structure in color space common to several very different databases. This common structure is due to the visual system rather than to the statistics

  3. Special Quasirandom Structures to Study the (K0.5Na0.5)NbO3 Random Alloy

    Science.gov (United States)

    2014-07-31

    and Na on the perovskite A-site. Using these structures, local variations in Na-O interactions are suggested to be the driving force behind the R3c to...structure patterns derived from the random distribution of K and Na on the perovskite A-site. Using these structures, local variations in Na-O...representing the physical properties of the ABO3 perovskite compounds PZT [14] and BaTiO3-SrTiO3 [15,16]. Unfortunately, these approaches require extensive

  4. Improvement of hypertension management by structured physician education and feedback system: cluster randomized trial.

    Science.gov (United States)

    Lüders, Stefan; Schrader, Joachim; Schmieder, Roland E; Smolka, Wenefrieda; Wegscheider, Karl; Bestehorn, Kurt

    2010-06-01

    We aimed to assess whether hypertension management with a structured physician information program and a feedback system leads to improved blood pressure (BP) control and cardiovascular outcomes. Cluster randomized (3 : 1), open, monitored, multicenter trial in Germany. Primary care-based physicians in the information group (IG) received detailed training on hypertension guidelines, feedback on target-level attainment, and a reminder to intensify treatment after each patient visit, whereas the observation/control group (CG) did not receive any such measures. A three-level mixed model was developed. Time-independent level differences between groups, group-independent changes, and nonparallel group-specific changes over time were tested. A total of 15 041 (78.1%) hypertensive patients were in the IG and 4213 (21.9%) in the CG. By 1-year follow-up, 82.9% of patients in the IG and 81.5% in the CG remained in the study. The guideline-oriented BP target was attained by 56.8% in the IG and 52.5% in the CG (+4.3%, P = 0.03), whereas the individual BP target was attained by 57.0% in the IG and 51% in the CG (P = NS). BP control in the IG was achieved 2 months earlier on average. Clinical inertia, defined as the absence of medication changes, despite noncontrol of BP, occurred significantly less often in the IG group. One-year cardiovascular outcomes did not differ between groups. The delivery of systematic information in connection with a feedback system reduces clinical inertia and improves guideline adherence. Although compared with earlier studies, the hypertension control rates obtained are higher, there is still considerable room for improvement.

  5. Structural insights from random mutagenesis of Campylobacter jejuni oligosaccharyltransferase PglB

    Directory of Open Access Journals (Sweden)

    Ihssen Julian

    2012-09-01

    Full Text Available Abstract Background Protein glycosylation is of fundamental importance in many biological systems. The discovery of N-glycosylation in bacteria and the functional expression of the N-oligosaccharyltransferase PglB of Campylobacter jejuni in Escherichia coli enabled the production of engineered glycoproteins and the study of the underlying molecular mechanisms. A particularly promising application for protein glycosylation in recombinant bacteria is the production of potent conjugate vaccines where polysaccharide antigens of pathogenic bacteria are covalently bound to immunogenic carrier proteins. Results In this study capsular polysaccharides of the clinically relevant pathogen Staphylococcus aureus serotype 5 (CP5 were expressed in Escherichia coli and linked in vivo to a detoxified version of Pseudomonas aeruginosa exotoxin (EPA. We investigated which amino acids of the periplasmic domain of PglB are crucial for the glycosylation reaction using a newly established 96-well screening system enabling the relative quantification of glycoproteins by enzyme-linked immunosorbent assay. A random mutant library was generated by error-prone PCR and screened for inactivating amino acid substitutions. In addition to 15 inactive variants with amino acid changes within the previously known, strictly conserved WWDYG motif of N-oligosaccharyltransferases, 8 inactivating mutations mapped to a flexible loop in close vicinity of the amide nitrogen atom of the acceptor asparagine as revealed in the crystal structure of the homologous enzyme C. lari PglB. The importance of the conserved loop residue H479 for glycosylation was confirmed by site directed mutagenesis, while a change to alanine of the adjacent, non-conserved L480 had no effect. In addition, we investigated functional requirements in the so-called MIV motif of bacterial N-oligosaccharyltransferases. Amino acid residues I571 and V575, which had been postulated to interact with the acceptor peptide, were

  6. Prior Elicitation, Assessment and Inference with a Dirichlet Prior

    Directory of Open Access Journals (Sweden)

    Michael Evans

    2017-10-01

    Full Text Available Methods are developed for eliciting a Dirichlet prior based upon stating bounds on the individual probabilities that hold with high prior probability. This approach to selecting a prior is applied to a contingency table problem where it is demonstrated how to assess the prior with respect to the bias it induces as well as how to check for prior-data conflict. It is shown that the assessment of a hypothesis via relative belief can easily take into account what it means for the falsity of the hypothesis to correspond to a difference of practical importance and provide evidence in favor of a hypothesis.

  7. The use of random decrement technique for identification of structural modes of vibration. [tested on a generalized payload and the space shuttle model

    Science.gov (United States)

    Ibrahim, S. R.

    1977-01-01

    An algorithm is developed to obtain the free responses of a structure from its random responses due to some unknown or known random input or inputs, using the random-decrement technique without changing time correlation between signals. The algorithm is tested using random responses from a 'generalized payload' model and from the 'Space Shuttle' model. The resulting free responses are then used to identify the modal characteristics of the two systems.

  8. Joint genome-wide prediction in several populations accounting for randomness of genotypes: A hierarchical Bayes approach. II: Multivariate spike and slab priors for marker effects and derivation of approximate Bayes and fractional Bayes factors for the complete family of models.

    Science.gov (United States)

    Martínez, Carlos Alberto; Khare, Kshitij; Banerjee, Arunava; Elzo, Mauricio A

    2017-03-21

    This study corresponds to the second part of a companion paper devoted to the development of Bayesian multiple regression models accounting for randomness of genotypes in across population genome-wide prediction. This family of models considers heterogeneous and correlated marker effects and allelic frequencies across populations, and has the ability of considering records from non-genotyped individuals and individuals with missing genotypes in any subset of loci without the need for previous imputation, taking into account uncertainty about imputed genotypes. This paper extends this family of models by considering multivariate spike and slab conditional priors for marker allele substitution effects and contains derivations of approximate Bayes factors and fractional Bayes factors to compare models from part I and those developed here with their null versions. These null versions correspond to simpler models ignoring heterogeneity of populations, but still accounting for randomness of genotypes. For each marker loci, the spike component of priors corresponded to point mass at 0 in R S , where S is the number of populations, and the slab component was a S-variate Gaussian distribution, independent conditional priors were assumed. For the Gaussian components, covariance matrices were assumed to be either the same for all markers or different for each marker. For null models, the priors were simply univariate versions of these finite mixture distributions. Approximate algebraic expressions for Bayes factors and fractional Bayes factors were found using the Laplace approximation. Using the simulated datasets described in part I, these models were implemented and compared with models derived in part I using measures of predictive performance based on squared Pearson correlations, Deviance Information Criterion, Bayes factors, and fractional Bayes factors. The extensions presented here enlarge our family of genome-wide prediction models making it more flexible in the

  9. Submicron structure random field on granular soil material with retinex algorithm optimization

    OpenAIRE

    Liang Yu; Tao Chenyuan; Zhou Bingcheng; Huang Shuai; Huang Linchong

    2017-01-01

    In this paper, a Retinex scale optimized image enhancement algorithm is proposed, which can enhance the micro vision image and eliminate the influence of the uneven illumination. Based on that, a random geometric model of the microstructure of granular materials is established with Monte-Carlo method, the numerical simulation including consolidation process of granular materials is compared with the experimental data. The results have proved that the random field method with Retinex image enh...

  10. Alkalinized lidocaine versus lidocaine gel as local anesthesia prior to intra-vesical botulinum toxin (BoNTA) injections: A prospective, single center, randomized, double-blind, parallel group trial of efficacy and morbidity.

    Science.gov (United States)

    Nambiar, Arjun K; Younis, Ayman; Khan, Zainab A; Hildrup, Iona; Emery, Simon J; Lucas, Malcolm G

    2016-04-01

    To assess the efficacy and morbidity of alkalinized lidocaine solution compared to lidocaine gel for intra-vesical anesthesia during botulinum toxin (BoNTA) injections in a statistically powered, prospective, parallel group, double-blind randomized controlled trial. Fifty-four patients of either sex were randomized to receive either alkalinized lidocaine (AL) solution (10 ml 8.4% sodium bicarbonate + 20 ml 2% lidocaine solution + 22 ml sterile Aquagel®) or lidocaine gel (LG) (22 ml standard 2% lidocaine gel Instillagel® + 30 ml 0.9% normal saline solution). Primary outcome was average pain (assessed by 100 mm visual analog score) felt during intra-vesical BoNTA injections performed at least 20 min after instillation. Secondary outcome was the rate of adverse events. Of 60 randomized patients 54 received the allocated intervention and were analyzed. Mean pain score in the AL group was 17.11 mm (95%CI 8.65-25.57 mm) and in the LG group was 19.53 mm (95%CI 13.03-26.03mm) with no significant difference between the groups. Cost of interventional medication in the AL group was almost double that of the LG group. No adverse events were attributable to local anesthetic instillation in either group. Alkalinized lidocaine solution is not superior to lidocaine gel for anesthesia during intra-vesical BoNTA injections, and the higher cost precludes its use over lidocaine gel at our centre. We have used the results of this study to adapt our local protocol for BoNTA injections and continue to use lidocaine gel as the local anesthetic of choice. Neurourol. Urodynam. 35:522-527, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  11. Randomized controlled trial of teaching practice nurses to carry out structured assessments of patients receiving depot antipsychotic injections.

    OpenAIRE

    Burns, T; Millar, E; Garland, C; Kendrick, T; Chisholm, B; Ross, F

    1998-01-01

    BACKGROUND: A third of patients with schizophrenia are out of contact with secondary services. Many of these patients receive maintenance medication as depot antipsychotics from practice nurses, most of whom have negligible training in mental health. AIM: To examine the impact of a structured assessment on the process of care and clinical status of schizophrenia patients by practice nurses who received a one-day training course. METHOD: All identified patients were randomly allocated to struc...

  12. Randomized controlled trial of outpatient mentalization-based treatment versus structured clinical management for borderline personality disorder.

    Science.gov (United States)

    Bateman, Anthony; Fonagy, Peter

    2009-12-01

    This randomized controlled trial tested the effectiveness of an 18-month mentalization-based treatment (MBT) approach in an outpatient context against a structured clinical management (SCM) outpatient approach for treatment of borderline personality disorder. Patients (N=134) consecutively referred to a specialist personality disorder treatment center and meeting selection criteria were randomly allocated to MBT or SCM. Eleven mental health professionals equal in years of experience and training served as therapists. Independent evaluators blind to treatment allocation conducted assessments every 6 months. The primary outcome was the occurrence of crisis events, a composite of suicidal and severe self-injurious behaviors and hospitalization. Secondary outcomes included social and interpersonal functioning and self-reported symptoms. Outcome measures, assessed at 6-month intervals, were analyzed using mixed effects logistic regressions for binary data, Poisson regression models for count data, and mixed effects linear growth curve models for self-report variables. Substantial improvements were observed in both conditions across all outcome variables. Patients randomly assigned to MBT showed a steeper decline of both self-reported and clinically significant problems, including suicide attempts and hospitalization. Structured treatments improve outcomes for individuals with borderline personality disorder. A focus on specific psychological processes brings additional benefits to structured clinical support. Mentalization-based treatment is relatively undemanding in terms of training so it may be useful for implementation into general mental health services. Further evaluations by independent research groups are now required.

  13. Phase structure of the O(n) model on a random lattice for n > 2

    DEFF Research Database (Denmark)

    Durhuus, B.; Kristjansen, C.

    1997-01-01

    We show that coarse graining arguments invented for the analysis of multi-spin systems on a randomly triangulated surface apply also to the O(n) model on a random lattice. These arguments imply that if the model has a critical point with diverging string susceptibility, then either γ = +1...... by (γ̃, γ) = (-1/m, 1/m+1), m = 2, 3, . . . We also show that at the critical points with positive string susceptibility exponent the average number of loops on the surface diverges while the average length of a single loop stays finite....

  14. Rapid sampling of molecular motions with prior information constraints.

    Directory of Open Access Journals (Sweden)

    Barak Raveh

    2009-02-01

    Full Text Available Proteins are active, flexible machines that perform a range of different functions. Innovative experimental approaches may now provide limited partial information about conformational changes along motion pathways of proteins. There is therefore a need for computational approaches that can efficiently incorporate prior information into motion prediction schemes. In this paper, we present PathRover, a general setup designed for the integration of prior information into the motion planning algorithm of rapidly exploring random trees (RRT. Each suggested motion pathway comprises a sequence of low-energy clash-free conformations that satisfy an arbitrary number of prior information constraints. These constraints can be derived from experimental data or from expert intuition about the motion. The incorporation of prior information is very straightforward and significantly narrows down the vast search in the typically high-dimensional conformational space, leading to dramatic reduction in running time. To allow the use of state-of-the-art energy functions and conformational sampling, we have integrated this framework into Rosetta, an accurate protocol for diverse types of structural modeling. The suggested framework can serve as an effective complementary tool for molecular dynamics, Normal Mode Analysis, and other prevalent techniques for predicting motion in proteins. We applied our framework to three different model systems. We show that a limited set of experimentally motivated constraints may effectively bias the simulations toward diverse predicates in an outright fashion, from distance constraints to enforcement of loop closure. In particular, our analysis sheds light on mechanisms of protein domain swapping and on the role of different residues in the motion.

  15. Randomized, open-label study to evaluate patient-reported outcomes with fingolimod after changing from prior disease-modifying therapy for relapsing multiple sclerosis: EPOC study rationale and design.

    Science.gov (United States)

    Cascione, Mark; Wynn, Daniel; Barbato, Luigi M; Pestreich, Linda; Schofield, Lesley; McCague, Kevin

    2013-07-01

    The study to Evaluate Patient OutComes, Safety, and Tolerability of Fingolimod (EPOC; NCT01216072) aimed to test the hypothesis that therapy change to oral Gilenya (Novartis AG, Stein, Switzerland) (fingolimod) improves patient-reported outcomes compared with standard-of-care disease-modifying therapy (DMT) in patients with relapsing multiple sclerosis; safety and tolerability were also assessed. This communication describes the study rationale and design. EPOC is a phase 4, open-label, multi-center study conducted in the US and Canada of patients with relapsing forms of multiple sclerosis who are candidates for therapy change. Therapy change eligibility was determined by the treating physician (US patients) or required an inadequate response to or poor tolerance for at least 1 MS therapy (Canadian patients). Patients were randomly assigned in a 3:1 ratio to 6 months of treatment with once-daily oral fingolimod 0.5 mg or standard-of-care DMTs. The primary study end-point was the change from baseline in treatment satisfaction as determined by the global satisfaction sub-scale of the Treatment Satisfaction Questionnaire for Medication. Secondary end-points included changes from baseline in perceived effectiveness and side-effects, and measures of activities of daily living, fatigue, depression, and quality-of-life. A 3-month open-label fingolimod extension was available for patients randomly assigned to the DMT group who successfully completed all study visits. Enrollment has been completed with 1053 patients; the patient population is generally older and has a longer duration of disease compared with populations from phase 3 studies of fingolimod. Inclusion criteria selected for patients with a sub-optimal experience with a previous DMT, limiting the collection of data on therapy change in patients who were satisfied with their previous DMT. Results of the EPOC study are anticipated in early 2013 and will inform treatment selection by providing patient

  16. Accommodating Uncertainty in Prior Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Picard, Richard Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vander Wiel, Scott Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-19

    A fundamental premise of Bayesian methodology is that a priori information is accurately summarized by a single, precisely de ned prior distribution. In many cases, especially involving informative priors, this premise is false, and the (mis)application of Bayes methods produces posterior quantities whose apparent precisions are highly misleading. We examine the implications of uncertainty in prior distributions, and present graphical methods for dealing with them.

  17. Association of efavirenz hypersusceptibility with virologic response in ACTG 368, a randomized trial of abacavir (ABC) in combination with efavirenz (EFV) and indinavir (IDV) in HIV-infected subjects with prior nucleoside analog experience.

    Science.gov (United States)

    Demeter, Lisa M; DeGruttola, Victor; Lustgarten, Stephanie; Bettendorf, Daniel; Fischl, Margaret; Eshleman, Susan; Spreen, William; Nguyen, Bach-Yen; Koval, Christine E; Eron, Joseph J; Hammer, Scott; Squires, Kathleen

    2008-01-01

    To evaluate the association of efavirenz hypersusceptibility (EFV-HS) with clinical outcome in a double-blind, placebo-controlled, randomized trial of EFV plus indinavir (EFV+IDV) vs. EFV+IDV plus abacavir (ABC) in 283 nucleoside-experienced HIV-infected patients. Rates of virologic failure were similar in the 2 arms at week 16 (p = .509). Treatment discontinuations were more common in the ABC arm (p = .001). Using logistic regression, there was no association between virologic failure and either baseline ABC resistance or regimen sensitivity score. Using 3 different genotypic scoring systems, EFV-HS was significantly associated with reduced virologic failure at week 16, independent of treatment assignment. In some patients on the nucleoside-sparing arm, the nucleoside-resistance mutation L74V was selected for in combination with the uncommonly occurring EFV-resistance mutations K103N+L100I; L74V was not detected as a minority variant, using clonal sequence analysis, when the nucleoside-sparing regimen was initiated. Premature treatment discontinuations in the ABC arm and the presence of EFV-HS HIV variants in this patient population likely made it difficult to detect a benefit of adding ABC to EFV+IDV. In addition, L74V, when combined with K103N+L100I, may confer a selective advantage to the virus that is independent of its effects on nucleoside resistance.

  18. Clinical efficacy, radiographic progression, and safety through 156 weeks of therapy with subcutaneous golimumab in combination with methotrexate in Japanese patients with active rheumatoid arthritis despite prior methotrexate therapy: final results of the randomized GO-FORTH trial.

    Science.gov (United States)

    Tanaka, Yoshiya; Harigai, Masayoshi; Takeuchi, Tsutomu; Yamanaka, Hisashi; Ishiguro, Naoki; Yamamoto, Kazuhiko; Miyasaka, Nobuyuki; Koike, Takao; Baker, Daniel; Ishii, Yutaka; Yoshinari, Toru

    2016-07-01

    To evaluate the safety and efficacy of golimumab + methotrexate (MTX) in Japanese patients with active rheumatoid arthritis (RA). Japanese patients with active RA despite MTX were randomized to placebo + MTX (Group 1, n = 88), golimumab 50 mg + MTX (Group 2, n = 86), or golimumab 100 mg + MTX (Group 3, n = 87). Patients with <20% improvement in swollen/tender joint counts entered early escape at week 16. At week 24, all remaining placebo patients crossed over to golimumab 50 mg. Efficacy assessments included ACR20, DAS28-ESR, and HAQ-DI. Radiographic progression was assessed with the van der Heijde-modified Sharp (vdH-S) score. ACR20 response rates in Group 1, Group 2, and Group 3 were 67.9, 86.1, and 82.4%, respectively, at week 52 and were maintained through week 104 (87.1, 94.0, and 88.7%) and week 156 (97.1, 94.1, and 89.5%). Proportions of patients with good/moderate DAS28-ESR response or clinically meaningful improvement in HAQ-DI were also maintained through week 156. The majority of patients did not experience radiographic progression through week 156. Among 257 golimumab-treated patients, 251 (97.7%) had ≥1 AE; 54 (21.0%) had ≥1 serious AE through week 156. Infections were the most common type of AE. Response to golimumab + MTX was maintained over 3 years in Japanese patients with active RA despite MTX. Safety results were consistent with the known safety profile of golimumab.

  19. Prior human papillomavirus-16/18 AS04-adjuvanted vaccination prevents recurrent high grade cervical intraepithelial neoplasia after definitive surgical therapy: Post-hoc analysis from a randomized controlled trial.

    Science.gov (United States)

    Garland, Suzanne M; Paavonen, Jorma; Jaisamrarn, Unnop; Naud, Paulo; Salmerón, Jorge; Chow, Song-Nan; Apter, Dan; Castellsagué, Xavier; Teixeira, Júlio C; Skinner, S Rachel; Hedrick, James; Limson, Genara; Schwarz, Tino F; Poppe, Willy A J; Bosch, F Xavier; de Carvalho, Newton S; Germar, Maria Julieta V; Peters, Klaus; Del Rosario-Raymundo, M Rowena; Catteau, Grégory; Descamps, Dominique; Struyf, Frank; Lehtinen, Matti; Dubin, Gary

    2016-12-15

    We evaluated the efficacy of the human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine in preventing HPV-related disease after surgery for cervical lesions in a post-hoc analysis of the PApilloma TRIal against Cancer In young Adults (PATRICIA; NCT00122681). Healthy women aged 15-25 years were randomized (1:1) to receive vaccine or control at months 0, 1 and 6 and followed for 4 years. Women were enrolled regardless of their baseline HPV DNA status, HPV-16/18 serostatus, or cytology, but excluded if they had previous or planned colposcopy. The primary and secondary endpoints of PATRICIA have been reported previously; the present post-hoc analysis evaluated efficacy in a subset of women who underwent an excisional procedure for cervical lesions after vaccination. The main outcome was the incidence of subsequent HPV-related cervical intraepithelial neoplasia grade 2 or greater (CIN2+) 60 days or more post-surgery. Other outcomes included the incidence of HPV-related CIN1+, and vulvar or vaginal intraepithelial neoplasia (VIN/VaIN) 60 days or more post-surgery. Of the total vaccinated cohort of 18,644 women (vaccine = 9,319; control = 9,325), 454 (vaccine = 190, control = 264) underwent an excisional procedure during the trial. Efficacy 60 days or more post-surgery for a first lesion, irrespective of HPV DNA results, was 88.2% (95% CI: 14.8, 99.7) against CIN2+ and 42.6% (-21.1, 74.1) against CIN1+. No VIN was reported and one woman in each group had VaIN2+ 60 days or more post-surgery. Women who undergo surgical therapy for cervical lesions after vaccination with the HPV-16/18 vaccine may continue to benefit from vaccination, with a reduced risk of developing subsequent CIN2+. © 2016 UICC.

  20. Structure-Related Optical Fingerprints in the Absorption Spectra of Colloidal Quantum Dots: Random Alloy vs. Core/Shell Systems

    CERN Document Server

    Mourad, Daniel

    2016-01-01

    We argue that the experimentally easily accessible optical absorption spectrum can often be used to distinguish between a random alloy phase and a stoichiometrically equivalent core/shell realization of ensembles of monodisperse colloidal semiconductor quantum dots without the need for more advanced structural characterization tools. Our proof-of-concept is performed by conceptually straightforward exact-disorder tight-binding calculations. The underlying stochastical tight-binding scheme only parametrizes bulk band structure properties and does not employ additional free parameters to calculate the optical absorption spectrum, which is an easily accessible experimental property. The method is applied to selected realizations of type-I Cd(Se,S) and type-II (Zn,Cd)(Se,S) alloyed quantum dots with an underlying zincblende crystal structure and the corresponding core/shell counterparts.

  1. An inverse method for the identification of a distributed random excitation acting on a vibrating structure. Theory

    Energy Technology Data Exchange (ETDEWEB)

    Granger, S.; Perotin, L. [Electricite de France (EDF), 78 - Chatou (France)

    1997-12-31

    Maintaining the PWR components under reliable operating conditions requires a complex design to prevent various damaging processes, including fatigue and wear problems due to flow-induced vibration. In many practical situations, it is difficult, if not impossible, to perform direct measurements or calculations of the external forces acting on vibrating structures. Instead, vibrational responses can often be conveniently measured. This paper presents an inverse method for estimating a distributed random excitation from the measurement of the structural response at a number of discrete points. This paper is devoted to the presentation of the theoretical development. The force identification method is based on a modal model for the structure and a spatial orthonormal decomposition of the excitation field. The estimation of the Fourier coefficients of this orthonormal expansion is presented. As this problem turns out to be ill-posed, a regularization process is introduced. The minimization problem associated to this process is then formulated and its solutions is developed. (author) 17 refs.

  2. Submicron structure random field on granular soil material with retinex algorithm optimization

    Science.gov (United States)

    Liang, Yu; Tao, Chenyuan; Zhou, Bingcheng; Huang, Shuai; Huang, Linchong

    2017-06-01

    In this paper, a Retinex scale optimized image enhancement algorithm is proposed, which can enhance the micro vision image and eliminate the influence of the uneven illumination. Based on that, a random geometric model of the microstructure of granular materials is established with Monte-Carlo method, the numerical simulation including consolidation process of granular materials is compared with the experimental data. The results have proved that the random field method with Retinex image enhancement algorithm is effective, the image of microstructure of granular materials becomes clear and the contrast ratio is improved, after using Retinex image enhancement algorithm to enhance the CT image. The fidelity of enhanced image is higher than that dealing with other method, which have explained that the algorithm can preserve the microstructure information of the image well. The result of numerical simulation is similar with the one obtained from conventional three axis consolidation test, which proves that the simulation result is reliable.

  3. Submicron structure random field on granular soil material with retinex algorithm optimization

    Directory of Open Access Journals (Sweden)

    Liang Yu

    2017-01-01

    Full Text Available In this paper, a Retinex scale optimized image enhancement algorithm is proposed, which can enhance the micro vision image and eliminate the influence of the uneven illumination. Based on that, a random geometric model of the microstructure of granular materials is established with Monte-Carlo method, the numerical simulation including consolidation process of granular materials is compared with the experimental data. The results have proved that the random field method with Retinex image enhancement algorithm is effective, the image of microstructure of granular materials becomes clear and the contrast ratio is improved, after using Retinex image enhancement algorithm to enhance the CT image. The fidelity of enhanced image is higher than that dealing with other method, which have explained that the algorithm can preserve the microstructure information of the image well. The result of numerical simulation is similar with the one obtained from conventional three axis consolidation test, which proves that the simulation result is reliable.

  4. Self-consistent electronic structure and segregation profiles of the Cu-Ni (001) random-alloy surface

    DEFF Research Database (Denmark)

    Ruban, Andrei; Abrikosov, I. A.; Kats, D. Ya.

    1994-01-01

    We have calculated the electronic structure and segregation profiles of the (001) surface of random Cu-Ni alloys with varying bulk concentrations by means of the coherent potential approximation and the linear muffin-tin-orbitals method. Exchange and correlation were included within the local......-density approximation. Temperature effects were accounted for by means of the cluster-variation method and, for comparison, by mean-field theory. The necessary interaction parameters were calculated by the Connolly-Williams method generalized to the case of a surface of a random alloy. We find the segregation profiles...... to be oscillatory with a strong preference for Cu to segregate towards the surface of the alloy....

  5. Structure and Randomness of Continuous-Time, Discrete-Event Processes

    Science.gov (United States)

    Marzen, Sarah E.; Crutchfield, James P.

    2017-10-01

    Loosely speaking, the Shannon entropy rate is used to gauge a stochastic process' intrinsic randomness; the statistical complexity gives the cost of predicting the process. We calculate, for the first time, the entropy rate and statistical complexity of stochastic processes generated by finite unifilar hidden semi-Markov models—memoryful, state-dependent versions of renewal processes. Calculating these quantities requires introducing novel mathematical objects (ɛ -machines of hidden semi-Markov processes) and new information-theoretic methods to stochastic processes.

  6. A cluster randomized controlled trial of a structured training programme for caregivers of inpatients after stroke (TRACS).

    Science.gov (United States)

    Forster, Anne; Young, John; Nixon, Jane; Kalra, Lalit; Smithard, David; Patel, Anita; Knapp, Martin; Monaghan, Josie; Breen, Rachel; Anwar, Shamaila; Farrin, Amanda

    2012-01-01

    The majority of stroke patients are discharged home dependent on informal caregivers, usually family members, to provide assistance with activities of daily living, including bathing, dressing, and toileting. Many caregivers feel unprepared for this role, and this may have a detrimental effect on both the patient and caregiver. To evaluate whether a structured, competency-based training programme for caregivers improves physical and psychological outcomes for patients and their caregivers after disabling stroke, and to determine if such a training programme is cost-effective. A cluster randomized controlled trial. The trial aims to recruit 25 patient and caregiver dyads from each of the 36 participating stroke rehabilitation units. Stroke units have been randomized to either the intervention or control group with randomization stratified by geographical region and quality of care. The intervention is the London Stroke Carer Training Course developed and evaluated in a previous single-centre study. The London Stroke Carer Training Course comprises a number of caregiver training sessions and competency assessment delivered while the patient is in the hospital and one follow-up session after discharge. The multidisciplinary teams in the units randomized to the intervention group have been trained to incorporate delivery of the London Stroke Carer Training Course into ward practice, while those randomized to the control group have continued to provide usual care according to national guidelines. The primary outcomes are extended activities of daily living for the patient and caregiver burden measured at six-months after recruitment. Secondary outcomes include mood and cost-effectiveness, with final follow-up at 12 months. © 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.

  7. Protein Ordered Sequences are Formed by Random Joining of Amino Acids in Protein 0th-Order Structure, Followed by Evolutionary Process

    Science.gov (United States)

    Ikehara, Kenji

    2014-12-01

    Only random processes should occur on the primitive Earth. In contrast, many ordered sequences are synthesized according to genetic information on the present Earth. In this communication, I have proposed an idea that protein 0th-order structures or specific amino acid compositions would mediate the transfer from random process to formation of ordered sequences, after formation of double-stranded genes.

  8. Full-field, high-spatial-resolution detection of local structural damage from low-resolution random strain field measurements

    Science.gov (United States)

    Yang, Yongchao; Sun, Peng; Nagarajaiah, Satish; Bachilo, Sergei M.; Weisman, R. Bruce

    2017-07-01

    Structural damage is typically a local phenomenon that initiates and propagates within a limited area. As such high spatial resolution measurement and monitoring is often needed for accurate damage detection. This requires either significantly increased costs from denser sensor deployment in the case of global simultaneous/parallel measurements, or increased measurement time and labor in the case of global sequential measurements. This study explores the feasibility of an alternative approach to this problem: a computational solution in which a limited set of randomly positioned, low-resolution global strain measurements are used to reconstruct the full-field, high-spatial-resolution, two-dimensional (2D) strain field and rapidly detect local damage. The proposed approach exploits the implicit low-rank and sparse data structure of the 2D strain field: it is highly correlated without many edges and hence has a low-rank structure, unless damage-manifesting itself as sparse local irregularity-is present and alters such a low-rank structure slightly. Therefore, reconstruction of the full-field, high-spatial-resolution strain field from a limited set of randomly positioned low-resolution global measurements is modeled as a low-rank matrix completion framework and damage detection as a sparse decomposition formulation, enabled by emerging convex optimization techniques. Numerical simulations on a plate structure are conducted for validation. The results are discussed and a practical iterative global/local procedure is recommended. This new computational approach should enable the efficient detection of local damage using limited sets of strain measurements.

  9. Effect of Periodontal Therapy on Arterial Structure and Function Among Aboriginal Australians: A Randomized, Controlled Trial

    National Research Council Canada - National Science Library

    Kapellas, Kostas; Maple-Brown, Louise J; Jamieson, Lisa M; Do, Loc G; O’Dea, Kerin; Brown, Alex; Cai, Tommy Y; Anstey, Nicholas M; Sullivan, David R; Wang, Hao; Celermajer, David S; Slade, Gary D; Skilton, Michael R

    2014-01-01

    .... Both diseases occur frequently in Aboriginal Australians. We hypothesized that nonsurgical periodontal therapy would improve measures of arterial function and structure that are subclinical indicators of atherosclerotic vascular disease...

  10. Secondary structure prediction of protein constructs using random incremental truncation and vacuum-ultraviolet CD spectroscopy

    CERN Document Server

    Pukáncsik, M; Matsuo, K; Gekko, K; Hart, D; Kézsmárki, I; Vértessy, B G

    2014-01-01

    A novel uracil-DNA degrading protein factor (termed UDE) was identified in Drosophila melanogaster with no significant structural and functional homology to other uracil-DNA binding or processing factors. Determination of the 3D structure of UDE will be a true breakthrough in description of the molecular mechanism of action of UDE catalysis, as well as in general uracil-recognition and nuclease action. The revolutionary ESPRIT technology was applied to the novel protein UDE to overcome problems in identifying soluble expressing constructs given the absence of precise information on domain content and arrangement. Nine specimen from the created numerous truncated constructs of UDE were choosen to dechiper structural and functional relationships. VUVCD with neural network was performed to define the secondary structure content and location of UDE and its truncated variants. The quantitative analysis demonstrated exclusive {\\alpha}-helical content for the full-length protein, which is preserved in the truncated ...

  11. Explaining the structure of inter-organizational networks using exponential random graph models

    NARCIS (Netherlands)

    Broekel, T.; Hartog, M.

    2013-01-01

    A key question raised in recent years is what factors determine the structure of interorganizational networks. Most research so far has focused on different forms of proximity between organizations, namely geographical, cognitive, social, institutional and organizational proximity, which are

  12. Effect of structured physical activity on prevention of serious fall injuries in adults aged 70-89: randomized clinical trial (LIFE Study)

    Science.gov (United States)

    OBJECTIVE: To test whether a long term, structured physical activity program compared with a health education program reduces the risk of serious fall injuries among sedentary older people with functional limitations. DESIGN: Multicenter, single blinded randomized trial (Lifestyle Interventions and ...

  13. Large deviations for random trees and the branching of RNA secondary structures.

    Science.gov (United States)

    Bakhtin, Yuri; Heitsch, Christine E

    2009-01-01

    We give a Large Deviation Principle (LDP) with explicit rate function for the distribution of vertex degrees in plane trees, a combinatorial model of RNA secondary structures. We calculate the typical degree distributions based on nearest neighbor free energies, and compare our results with the branching configurations found in two sets of large RNA secondary structures. We find substantial agreement overall, with some interesting deviations which merit further study.

  14. Recombinant azurin-CdSe/ZnS hybrid structures for nanoscale resistive random access memory device.

    Science.gov (United States)

    Yagati, Ajay Kumar; Kim, Sang-Uk; Lee, Taek; Min, Junhong; Choi, Jeong-Woo

    2017-04-15

    In the present study, we developed a biohybrid material composed of recombinant azurin and CdSe-ZnS quantum dot to perform as a resistive random access memory (ReRAM) device. Site specific amino acid sequences were introduced in azurin to bind with the surface of CdSe-ZnS nanoparticle allowing the formation of a hybrid and voltage-driven switching enabled to develop a resistive random access memory (ReRAM) device. The analytical measurements confirmed that the azurin and CdSe-ZnS nanoparticles were well conjugated and formed into a single hybrid. Further, reversible, bistable switching along with repeatable writing-reading-erasing processes on individual azurin/CdSe-ZnS hybrid at nanoscale was achieved on the hybrid device. The device was programmed tested for 50 cycles with an ON/OFF ratio and measured to be of three orders of magnitude. The developed device shown good stability and repeatability and operates at low voltages thus makes it promising candidate for future memory device applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Radiation breakage of DNA: a model based on random-walk chromatin structure

    Science.gov (United States)

    Ponomarev, A. L.; Sachs, R. K.

    2001-01-01

    Monte Carlo computer software, called DNAbreak, has recently been developed to analyze observed non-random clustering of DNA double strand breaks in chromatin after exposure to densely ionizing radiation. The software models coarse-grained configurations of chromatin and radiation tracks, small-scale details being suppressed in order to obtain statistical results for larger scales, up to the size of a whole chromosome. We here give an analytic counterpart of the numerical model, useful for benchmarks, for elucidating the numerical results, for analyzing the assumptions of a more general but less mechanistic "randomly-located-clusters" formalism, and, potentially, for speeding up the calculations. The equations characterize multi-track DNA fragment-size distributions in terms of one-track action; an important step in extrapolating high-dose laboratory results to the much lower doses of main interest in environmental or occupational risk estimation. The approach can utilize the experimental information on DNA fragment-size distributions to draw inferences about large-scale chromatin geometry during cell-cycle interphase.

  16. A STRUCTURED PHYSICAL ACTIVITY AND HEALTH CARE EDUCATION BEATS POSTPARTUM DEPRESSION FOR PRIMIPARA MOTHERS: A PILOT RANDOMIZED CONTROLLED TRAIL

    Directory of Open Access Journals (Sweden)

    A.Thiruppathi

    2014-08-01

    Full Text Available Background: First time mothers in particular may feel anxious about how they are going to cope with looking after themselves and their newborn. Most Indian women believe that they have little or no control over their pregnancies or outcomes. The aim of this study was to evaluate the effect of a Structured Physical Activity and Health Care Education program on the psychological well-being for Primipara mothers in postpartum period. Methods: This study was a Randomized Controlled Trail. Primipara mothers who were ready for discharge from The Narayana Medical College & General Hospital in postnatal ward were eligible for this study. Forty one (41 Primipara mothers randomized onto the trail. The experimental group(n=20 received an 4 week “Structured Physical Activity” (SPA program, including Structured Physical Activity provided by a team of health care professionals combined with parenting education & counseling. The other group (n=21 Health Care Education Only (HCEO received only the same educational material as the experimental group. In pre and post schedule outcome measures of both SPA&HCEO groups were assessed with Psychological well-being (Positive Affect Balance Scale, Depressive symptoms (Edinburgh Postpartum Depression Scale, and Physical activity were assessed at baseline, 4th week and then 8th week later. Results: The improvement was significantly high in well-being scores, depressive symptoms and physical activity of the (SPA group compared with the (HCEO group over the study period and this effect was maintained 8 weeks after completion of the program. Conclusion: A Structured Physical Activity and Health Care Education program is effective in improving the well-being for Primipara mothers in postpartum period. Continuous use of this program may reduce long-term problems such as postpartum depression and it will change the women’s Physical, emotional and social health.

  17. Evaluation of vaccination strategies for SIR epidemics on random networks incorporating household structure

    CERN Document Server

    Ball, Frank

    2016-01-01

    This paper is concerned with the analysis of vaccination strategies in a stochastic SIR (susceptible $\\to$ infected $\\to$ removed) model for the spread of an epidemic amongst a population of individuals with a random network of social contacts that is also partitioned into households. Under various vaccine action models, we consider both household-based vaccination schemes, in which the way in which individuals are chosen for vaccination depends on the size of the households in which they reside, and acquaintance vaccination, which targets individuals of high degree in the social network. For both types of vaccination scheme, assuming a large population with few initial infectives, we derive a threshold parameter which determines whether or not a large outbreak can occur and also the probability and fraction of the population infected by such an outbreak. The performance of these schemes is studied numerically, focusing on the influence of the household size distribution and the degree distribution of the soc...

  18. Workshop on Strategic Behavior and Phase Transitions in Random and Complex Combinatorial Structures : Extended Abstracts

    CERN Document Server

    Kirousis, Lefteris; Ortiz-Gracia, Luis; Serna, Maria

    2017-01-01

    This book is divided into two parts, the first of which seeks to connect the phase transitions of various disciplines, including game theory, and to explore the synergies between statistical physics and combinatorics. Phase Transitions has been an active multidisciplinary field of research, bringing together physicists, computer scientists and mathematicians. The main research theme explores how atomic agents that act locally and microscopically lead to discontinuous macroscopic changes. Adopting this perspective has proven to be especially useful in studying the evolution of random and usually complex or large combinatorial objects (like networks or logic formulas) with respect to discontinuous changes in global parameters like connectivity, satisfiability etc. There is, of course, an obvious strategic element in the formation of a transition: the atomic agents “selfishly” seek to optimize a local parameter. However, up to now this game-theoretic aspect of abrupt, locally triggered changes had not been e...

  19. Gaussian Mixture Random Coefficient model based framework for SHM in structures with time-dependent dynamics under uncertainty

    Science.gov (United States)

    Avendaño-Valencia, Luis David; Fassois, Spilios D.

    2017-12-01

    The problem of vibration-based damage diagnosis in structures characterized by time-dependent dynamics under significant environmental and/or operational uncertainty is considered. A stochastic framework consisting of a Gaussian Mixture Random Coefficient model of the uncertain time-dependent dynamics under each structural health state, proper estimation methods, and Bayesian or minimum distance type decision making, is postulated. The Random Coefficient (RC) time-dependent stochastic model with coefficients following a multivariate Gaussian Mixture Model (GMM) allows for significant flexibility in uncertainty representation. Certain of the model parameters are estimated via a simple procedure which is founded on the related Multiple Model (MM) concept, while the GMM weights are explicitly estimated for optimizing damage diagnostic performance. The postulated framework is demonstrated via damage detection in a simple simulated model of a quarter-car active suspension with time-dependent dynamics and considerable uncertainty on the payload. Comparisons with a simpler Gaussian RC model based method are also presented, with the postulated framework shown to be capable of offering considerable improvement in diagnostic performance.

  20. Improving the quality of life of geriatric cancer patients with a structured multidisciplinary intervention: a randomized controlled trial.

    Science.gov (United States)

    Lapid, Maria I; Rummans, Teresa A; Brown, Paul D; Frost, Marlene H; Johnson, Mary E; Huschka, Mashele M; Sloan, Jeff A; Richardson, Jarrett W; Hanson, Jean M; Clark, Matthew M

    2007-06-01

    To examine the potential impact of elderly age on response to participation in a structured, multidisciplinary quality-of-life (QOL) intervention for patients with advanced cancer undergoing radiation therapy. Study design was a randomized stratified, two group, controlled clinical trial in the setting of a tertiary care comprehensive cancer center. Subjects with newly diagnosed cancer and an estimated 5-year survival rate of 0%-50% who required radiation therapy were recruited and randomly assigned to either an intervention group or a standard care group. The intervention consisted of eight 90-min sessions designed to address the five QOL domains of cognitive, physical, emotional, spiritual, and social functioning. QOL was measured using Spitzer uniscale and linear analogue self-assessment (LASA) at baseline and weeks 4, 8, and 27. Of the 103 study participants, 33 were geriatric (65 years or older), of which 16 (mean age 72.4 years) received the intervention and 17 (mean age 71.4 years) were assigned to the standard medical care. The geriatric participants who completed the intervention had higher QOL scores at baseline, at week 4 and at week 8, compared to the control participants. Our results demonstrate that geriatric patients with advanced cancer undergoing radiation therapy will benefit from participation in a structured multidisciplinary QOL intervention. Therefore, geriatric individuals should not be excluded from participating in a cancer QOL intervention, and, in fact, elderly age may be an indicator of strong response to a QOL intervention. Future research should further explore this finding.

  1. The Influence of Family Structure on Sexual Activity in a Randomized Effectiveness Trial for Minority Youth

    Science.gov (United States)

    Sherr, Michael E.; Crow, Janet; Stamey, James; Jones, Johnny; Dyer, Preston

    2012-01-01

    This study examined the influence of family structure on the outcomes of a sex education program in Miami, Florida. Using an experimental design, data collection occurred at pretest, 3-month, and 6-month follow-up with a sample of teenagers from high schools with a large majority of minority youth, assigned into treatment (n = 549) and control (n…

  2. Bayesian exponential random graph modeling of whole-brain structural networks across lifespan

    NARCIS (Netherlands)

    Sinke, Michel R T; Dijkhuizen, Rick M; Caimo, Alberto; Stam, Cornelis J; Otte, Wim

    2016-01-01

    Descriptive neural network analyses have provided important insights into the organization of structural and functional networks in the human brain. However, these analyses have limitations for inter-subject or between-group comparisons in which network sizes and edge densities may differ, such as

  3. Optimum seismic structural design based on random vibration and fuzzy graded damages

    Science.gov (United States)

    Cheng, Franklin Y.; Ou, Jin-Ping

    1990-01-01

    This paper presents the fuzzy dynamical reliability and failure probability as well as the basic principles and the analytical method of loss assessment for nonlinear seismic steel structures. Also presented is the optimization formulation and a numerical example for double objectives, initial construction cost and expected failure loss, and dynamical reliability constraints. The earthquake ground motion is based on a stationary filtered non-white noise and the fuzzy damage grade is described by damage index.

  4. Non-random seasonal variation in the structure of a Mediterranean snake community

    OpenAIRE

    Filippi, E.; L. Luiselli

    2007-01-01

    The community structure in relation to habitat type was studied in a Mediterranean community of snakes from Canale Monterano, central Italy. Habitat data for snakes were analysed both overall and divided by season, i.e. spring (April–June) and summer (July–September). Community analyses were performed using null models (RA2 and RA3 algorithms) and Monte Carlo simulations on habitat niche overlap estimates. Null models suggested that the community was assem...

  5. New eco-friendly random copolyesters based on poly(propylene cyclohexanedicarboxylate: Structure-properties relationships

    Directory of Open Access Journals (Sweden)

    L. Genovese

    2015-11-01

    Full Text Available A series of novel random copolymers of poly(propylene 1,4-cyclohexanedicarboxylate (PPCE containing neo -pentyl glycol sub-unit (P(PCExNCEy were synthesized and characterized in terms of molecular and solid-state properties. In addition, biodegradability studies in compost have been conducted. The copolymers displayed a high and similar thermal stability with respect to PPCE. At room temperature, all the copolymers appeared as semicrystalline materials: the main effect of copolymerization was a lowering of crystallinity degree (χc and a decrease of the melting temperature compared to the parent homopolymer. In particular, Wide Angle X-Ray diffraction (WAXD measurements indicated that P(PCExNCEy copolymers are characterized by cocrystallization, PNCE counits cocrystallizing in PPCE crystalline phase. Final properties and biodegradation rate of the materials under study were strictly dependent on copolymer composition and χc. As a matter of fact, the elastic modulus and the elongation at break decreased and increased, respectively, as neopentyl glycol cyclohexanedicarboxylate (NCE unit content was increased. The presence of a rigid-amorphous phase was evidenced by means of Dynamic Mechanical Thermal Analysis (DMTA analysis in all the samples under investigation. Lastly, the biodegradation rate of P(PCExNCEy copolymers was found to slightly increase with the increasing of NCE molar content.

  6. Existence Results for a Michaud Fractional, Nonlocal, and Randomly Position Structured Fragmentation Model

    Directory of Open Access Journals (Sweden)

    Emile Franc Doungmo Goufo

    2014-01-01

    Full Text Available Until now, classical models of clusters’ fission remain unable to fully explain strange phenomena like the phenomenon of shattering (Ziff and McGrady, 1987 and the sudden appearance of infinitely many particles in some systems having initial finite number of particles. That is why there is a need to extend classical models to models with fractional derivative order and use new and various techniques to analyze them. In this paper, we prove the existence of strongly continuous solution operators for nonlocal fragmentation models with Michaud time derivative of fractional order (Samko et al., 1993. We focus on the case where the splitting rate is dependent on size and position and where new particles generating from fragmentation are distributed in space randomly according to some probability density. In the analysis, we make use of the substochastic semigroup theory, the subordination principle for differential equations of fractional order (Prüss, 1993, Bazhlekova, 2000, the analogy of Hille-Yosida theorem for fractional model (Prüss, 1993, and useful properties of Mittag-Leffler relaxation function (Berberan-Santos, 2005. We are then able to show that the solution operator to the full model is positive and contractive.

  7. Multiscale modeling of interwoven Kevlar fibers based on random walk to predict yarn structural response

    Science.gov (United States)

    Recchia, Stephen

    Kevlar is the most common high-end plastic filament yarn used in body armor, tire reinforcement, and wear resistant applications. Kevlar is a trade name for an aramid fiber. These are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited. The bulk material is extruded into filaments that are bound together into yarn, which may be chorded with other materials as in car tires, woven into a fabric, or layered in an epoxy to make composite panels. The high tensile strength to low weight ratio makes this material ideal for designs that decrease weight and inertia, such as automobile tires, body panels, and body armor. For designs that use Kevlar, increasing the strength, or tenacity, to weight ratio would improve performance or reduce cost of all products that are based on this material. This thesis computationally and experimentally investigates the tenacity and stiffness of Kevlar yarns with varying twist ratios. The test boundary conditions were replicated with a geometrically accurate finite element model, resulting in a customized code that can reproduce tortuous filaments in a yarn was developed. The solid model geometry capturing filament tortuosity was implemented through a random walk method of axial geometry creation. A finite element analysis successfully recreated the yarn strength and stiffness dependency observed during the tests. The physics applied in the finite element model was reproduced in an analytical equation that was able to predict the failure strength and strain dependency of twist ratio. The analytical solution can be employed to optimize yarn design for high strength applications.

  8. Random vibration of linear and nonlinear structural systems with singular matrices: A frequency domain approach

    Science.gov (United States)

    Kougioumtzoglou, I. A.; Fragkoulis, V. C.; Pantelous, A. A.; Pirrotta, A.

    2017-09-01

    A frequency domain methodology is developed for stochastic response determination of multi-degree-of-freedom (MDOF) linear and nonlinear structural systems with singular matrices. This system modeling can arise when a greater than the minimum number of coordinates/DOFs is utilized, and can be advantageous, for instance, in cases of complex multibody systems where the explicit formulation of the equations of motion can be a nontrivial task. In such cases, the introduction of additional/redundant DOFs can facilitate the formulation of the equations of motion in a less labor intensive manner. Specifically, relying on the generalized matrix inverse theory, a Moore-Penrose (M-P) based frequency response function (FRF) is determined for a linear structural system with singular matrices. Next, relying on the M-P FRF a spectral input-output (excitation-response) relationship is derived in the frequency domain for determining the linear system response power spectrum. Further, the above methodology is extended via statistical linearization to account for nonlinear systems. This leads to an iterative determination of the system response mean vector and covariance matrix. Furthermore, to account for singular matrices, the generalization of a widely utilized formula that facilitates the application of statistical linearization is proved as well. The formula relates to the expectation of the derivatives of the system nonlinear function and is based on a Gaussian response assumption. Several linear and nonlinear MDOF structural systems with singular matrices are considered as numerical examples for demonstrating the validity and applicability of the developed frequency domain methodology.

  9. The role of a structured exercise training program on cardiac structure and function after acute myocardial infarction: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Fontes-Carvalho, Ricardo; Sampaio, Francisco; Teixeira, Madalena; Gama, Vasco; Leite-Moreira, Adelino F

    2015-03-12

    Exercise training is effective in improving functional capacity and quality of life in patients with coronary artery disease, but its effects on left ventricular systolic and diastolic function are controversial. Diastolic dysfunction is a major determinant of adverse outcome after myocardial infarction and, contrary to systolic function, no therapy or intervention has proved to significantly improve diastolic function. Data from animal studies and from patients with diastolic heart failure has suggested that exercise training can have a positive effect on diastolic function parameters. This trial aims to evaluate if a structured exercise training program can improve resting left ventricular diastolic and systolic function in patients who have had an acute myocardial infarction. This is a phase II, prospective, randomized, open-label, blinded-endpoint trial that will include at least 96 consecutive patients who have had an acute myocardial infarction one month previously. Patients will be randomized (1:1) to an exercise training program or a control group, receiving standard of care. At enrolment, and at the end of the follow-up period, patients will be submitted to an echocardiography (with detailed assessment of diastolic and systolic function using recent consensus guidelines), cardiopulmonary exercise testing, an anthropometric assessment, blood testing, and clinical evaluation. Patients randomized to the intervention group will be submitted to an eight-week outpatient exercise program, combining endurance and resistance training, for three sessions per week. The primary endpoint will be the change in lateral E' velocity immediately after the eight-week exercise training program. Secondary endpoints will include other echocardiographic parameters of left ventricular diastolic and systolic function, cardiac structure, metabolic and inflammation biomarkers (high-sensitivity C-reactive protein and pro-BNP), functional capacity (peak oxygen consumption and

  10. Random lock-in intervals for tubular structural elements subject to simulated natural wind

    DEFF Research Database (Denmark)

    Christensen, Claus F.; Ditlevsen, Ove Dalager

    1999-01-01

    The paper reports on wind tunnel experiments with an elastically suspended circular cylinder vibrating under the excitation of natural wind of high turbulence degree. The natural wind turbulence was simulated bysuperposing the low frequency part of the natural wind turbulence on the background high...... structural elements subject to thenatural wind. The engineering relevance of the investigation is supported by comparing with the unrealistic highlyconservative rules of wind induced fatique commonly given in codes of practice. The stochastic lock-in model aswell as the related fatigue calculation procedure...

  11. The Prior Internet Resources 2017

    DEFF Research Database (Denmark)

    Engerer, Volkmar Paul; Albretsen, Jørgen

    2017-01-01

    The Prior Internet Resources (PIR) are presented. Prior’s unpublished scientific manuscripts and his wast letter correspondence with fellow researchers at the time, his Nachlass, is now subject to transcription by Prior-researchers worldwide, and form an integral part of PIR. It is demonstrated...... that the PIR, defined as the virtual space delimited by the three content areas and Internet domains: 1) Priorstudies, 2) Prior Virtual Lab, and 3) Nachlass), contains six information systems of five distinct types. The informations systems are grouped into a “Transcriber Loop” to illustrate how unpublished...... material from the archive boxes goes through a transcription process to end in the Nachlass. A box taxonomy defines the transcription project’s hub. Together with the “Transcriber Loop” this setup makes it possible to use the boxlists in conjunction with a Priorbibliography also in PIR as a showcase...

  12. Structure and mechanical properties of supramolecular random copolymer hydrogels cross linked by hydrophobic aggregates.

    Science.gov (United States)

    Vogt, Bryan; Wiener, Clinton; Wang, Chao; Weiss, Bob

    Stress dissipation mechanisms are critical to improving the toughness of hydrogels. The use of reversible hydrophobic associations for crosslnking of hydrogels provides such a mechanism for toughening, but can also lead to the creep of the hydrogel as the crosslinks break and reform. The morphology of the hydrophobic aggregates thus is critical to the mechanical properties of the hydrogels. In this work, we will demonstrate how the processing of these copolymers impacts the hydrogel structure and this structure is correlated with the mechanical properties through a combination of small angle scattering, rheology, and tensile measurements. The hydrophilic and hydrophobic chemistries in the copolymer can be used to tune the water content and strength of the crosslinks, while the copolymer composition provides the number density of crosslinks and also acts to modulate the swelling of the hydrogel. These copolymers as well as their hydrogels can in general use traditional polymer processing, but the details of this processing impacts both the nanoscale morphology and the resultant mechanical properties of the hydrogels. This work was financially supported by the Civil, Mechanical and Manufacturing Innovation (CMMI) Division in the Directorate for Engineering of the National Science Foundation, Grant. CMMI-1300212.

  13. Experimental estimation of in vacuo structural admittance using random sources in a non-anechoic room.

    Science.gov (United States)

    Williams, Earl G; Tippmann, Jeffery D; Rakotonarivo, Sandrine T; Waters, Zachary J; Roux, Philippe; Kuperman, W A

    2017-07-01

    Identification of unexploded ordinance buried in the sediment in the littoral waters throughout the world is a problem of great concern. When illuminated by low-frequency sonar some of these targets exhibit an elastic response that can be used to identify them. This elastic behavior is embodied and identified by a quantity called the in vacuo structural admittance matrix Ys, a relationship between the sonar-induced forces and resulting vibration on its surface. When it is known it can be combined with surface impedances to predict the three-dimensional bistatic scattering in any fluid-like media and for any burial state (depth and orientation). At the heart of this is the measurement of Ys and it is demonstrated in this paper that this can be accomplished by studying the target in a simple (acoustically unaltered) in-air laboratory environment. The target chosen in this study is a thick spherical shell that was illuminated by a nearly spatially isotropic array of remote loudspeakers. Ys is constructed from ensemble averages of the cross-correlations of eight collocated accelerometers and microphones placed on the surface of the object. The structural admittance determined from the data showed excellent agreement with theory.

  14. Finding Oxygen Reservoir by Using Extremely Small Test Cell Structure for Resistive Random Access Memory with Replaceable Bottom Electrode.

    Science.gov (United States)

    Kinoshita, Kentaro; Koh, Sang-Gyu; Moriyama, Takumi; Kishida, Satoru

    2015-12-22

    Although the presence of an oxygen reservoir (OR) is assumed in many models that explain resistive switching of resistive random access memory (ReRAM) with electrode/metal oxide (MO)/electrode structures, the location of OR is not clear. We have previously reported a method, which involved the use of an AFM cantilever, for preparing an extremely small ReRAM cell that has a removable bottom electrode (BE). In this study, we used this cell structure to specify the location of OR. Because an anode is often assumed to work as OR, we investigated the effect of changing anodes without changing the MO layer and the cathode on the occurrence of reset. It was found that the reset occurred independently of the catalytic ability and Gibbs free energy (ΔG) of the anode. Our proposed structure enabled to determine that the reset was caused by repairing oxygen vacancies of which a filament consists due to the migration of oxygen ions from the surrounding area when high ΔG anode metal is used, whereas by oxidizing the anode due to the migration of oxygen ions from the MO layer when low ΔG anode metal is used, suggesting the location of OR depends on ΔG of the anode.

  15. Effects of Hebbian learning on the dynamics and structure of random networks with inhibitory and excitatory neurons.

    Science.gov (United States)

    Siri, Benoît; Quoy, Mathias; Delord, Bruno; Cessac, Bruno; Berry, Hugues

    2007-01-01

    The aim of the present paper is to study the effects of Hebbian learning in random recurrent neural networks with biological connectivity, i.e. sparse connections and separate populations of excitatory and inhibitory neurons. We furthermore consider that the neuron dynamics may occur at a (shorter) time scale than synaptic plasticity and consider the possibility of learning rules with passive forgetting. We show that the application of such Hebbian learning leads to drastic changes in the network dynamics and structure. In particular, the learning rule contracts the norm of the weight matrix and yields a rapid decay of the dynamics complexity and entropy. In other words, the network is rewired by Hebbian learning into a new synaptic structure that emerges with learning on the basis of the correlations that progressively build up between neurons. We also observe that, within this emerging structure, the strongest synapses organize as a small-world network. The second effect of the decay of the weight matrix spectral radius consists in a rapid contraction of the spectral radius of the Jacobian matrix. This drives the system through the "edge of chaos" where sensitivity to the input pattern is maximal. Taken together, this scenario is remarkably predicted by theoretical arguments derived from dynamical systems and graph theory.

  16. A microstructure-guided constitutive modeling approach for random heterogeneous materials: Application to structural binders

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sumanta; Maroli, Amit; Singh, Sudhanshu S.; Stannard, Tyler; Xiao, Xianghui; Chawla, Nikhilesh; Neithalath, Narayanan

    2016-06-01

    This paper presents a microstructure-guided modeling approach to predict the effective elastic response of heterogeneous materials, and demonstrates its application toward two highly heterogeneous, uncon- ventional structural binders, i.e., iron carbonate and fly ash geopolymer. Microstructural information from synchrotron X-ray tomography (XRT) and intrinsic elastic properties of component solid phases from statistical nanoindentation are used as the primary inputs. The virtual periodic 3D microstructure reconstructed using XRT, along with periodic boundary conditions is used as a basis for strain- controlled numerical simulation scheme in the linear elastic range to predict the elastic modulus as well as the stresses in the microstructural phases. The elastic modulus of the composite material predicted from the microstructure-based constitutive modeling approach correlates very well with experimental measurements for both the materials considered. This technique efficiently links the microstructure to mechanical properties of interest and helps develop material design guidelines for novel heterogeneous composites

  17. Structure of Sn1−xGex random alloys as obtained from the coherent potential approximation

    KAUST Repository

    Pulikkotil, J. J.

    2011-08-09

    The structure of the Sn1−xGex random alloys is studied using density functional theory and the coherent potential approximation. We report on the deviation of the Sn1−xGex alloys from Vegard’s law, addressing their full compositional range. The findings are compared to the related Si1−xGex alloys and to experimental results. Interestingly, the deviation from Vegard’s law is quantitatively and qualitatively different between the Sn1−xGex and Si1−xGex alloys. An almost linear dependence of the bulk modulus as a function of composition is found for Si1−xGex, whereas for Sn1−xGex the dependence is strongly nonlinear.

  18. A novel multiplexer-based structure for random access memory cell in quantum-dot cellular automata

    Science.gov (United States)

    Naji Asfestani, Mazaher; Rasouli Heikalabad, Saeed

    2017-09-01

    Quantum-dot cellular automata (QCA) is a new technology in scale of nano and perfect replacement for CMOS circuits in the future. Memory is one of the basic components in any digital system, so designing the random access memory (RAM) with high speed and optimal in QCA is important. In this paper, by employing the structure of multiplexer, a novel RAM cell architecture is proposed. The proposed architecture is implemented without the coplanar crossover approach. The proposed architecture is simulated using the QCADesigner version 2.0.3 and QCAPro. The simulation results demonstrate that the proposed QCA RAM architecture has the best performance in terms of delay, circuit complexity, area, cell count and energy consumption in comparison with other QCA RAM architectures.

  19. Quantitative Structure Activity Relationship study of the Anti-Hepatitis Peptides employing Random Forests and Extra-trees regressors.

    Science.gov (United States)

    Mishra, Gunjan; Sehgal, Deepak; Valadi, Jayaraman K

    2017-01-01

    Antimicrobial peptides are host defense peptides being viewed as replacement to broad-spectrum antibiotics due to varied advantages. Hepatitis is the commonest infectious disease of liver, affecting 500 million globally with reported adverse side effects in treatment therapy. Antimicrobial peptides active against hepatitis are called as anti-hepatitis peptides (AHP). In current work, we present Extratrees and Random Forests based Quantitative Structure Activity Relationship (QSAR) regression modeling using extracted sequence based descriptors for prediction of the anti-hepatitis activity. The Extra-trees regression model yielded a very high performance in terms coefficient of determination (R2) as 0.95 for test set and 0.7 for the independent dataset. We hypothesize that the developed model can further be used to identify potentially active anti-hepatitis peptides with a high level of reliability.

  20. Acquisition of multiple prior distributions in tactile temporal order judgment

    Directory of Open Access Journals (Sweden)

    Yasuhito eNagai

    2012-08-01

    Full Text Available The Bayesian estimation theory proposes that the brain acquires the prior distribution of a task and integrates it with sensory signals to minimize the effect of sensory noise. Psychophysical studies have demonstrated that our brain actually implements Bayesian estimation in a variety of sensory-motor tasks. However, these studies only imposed one prior distribution on participants within a task period. In this study, we investigated the conditions that enable the acquisition of multiple prior distributions in temporal order judgment (TOJ of two tactile stimuli across the hands. In Experiment 1, stimulation intervals were randomly selected from one of two prior distributions (biased to right hand earlier and biased to left hand earlier in association with color cues (green and red, respectively. Although the acquisition of the two priors was not enabled by the color cues alone, it was significant when participants shifted their gaze (above or below in response to the color cues. However, the acquisition of multiple priors was not significant when participants moved their mouths (opened or closed. In Experiment 2, the spatial cues (above and below were used to identify which eye position or retinal cue position was crucial for the eye-movement-dependent acquisition of multiple priors in Experiment 1. The acquisition of the two priors was significant when participants moved their gaze to the cues (i.e., the cue positions on the retina were constant across the priors, as well as when participants did not shift their gazes (i.e., the cue positions on the retina changed according to the priors. Thus, both eye and retinal cue positions were effective in acquiring multiple priors. Based on previous neurophysiological reports, we discuss possible neural correlates that contribute to the acquisition of multiple priors.

  1. Effects of structured exercise and pharmacotherapy vs. pharmacotherapy for adults with depressive symptoms: A randomized clinical trial.

    Science.gov (United States)

    Carneiro, Lara S F; Fonseca, António Manuel; Vieira-Coelho, Maria Augusta; Mota, Maria Paula; Vasconcelos-Raposo, José

    2015-12-01

    Physical exercise has been consistently documented as a complementary therapy in the treatment of depressive disorders. However, despite a higher prevalence among women compared to men, the trials developed in women are scarce. In addition, the optimal dosage of exercise capable of producing benefits that reduce depressive symptoms remains unclear. This clinical trial is designed to measure the effect of a structured physical exercise program as a complement to antidepressant medication in the treatment of women with depression. From July 2013 to May 2014, we implemented a randomized controlled trial (HAPPY BRAIN study). A total of 26 women (aged 50.16 ± 12.08) diagnosed with clinical depression were randomized either to a supervised aerobic exercise group (45-50 min/week three times a week for four months) plus pharmacotherapy (intervention group), or only antidepressant medication (control group). The exercise group presented a decrease in BDI-II and DASS-21 total score scales. Relatively to DASS-21, it showed a significant decrease in anxiety and stress. The exercise group when compared to a control group showed improvement in relation to physical functioning parameters between baseline and post-intervention. Moreover, anthropometric parameters presented only significant differences between groups in fat mass percentage. Nonetheless, no differences were found between groups in weight, body mass index, waist circumference, and self-esteem. Our results showed that supervised structured aerobic exercise training could be an effective adjuvant therapy for treating women with depression, reducing depressive symptomatology and improving physical fitness. A key factor of this improvement included strict control of exercise workload parameters and adjustment to each subject's capacity. In our study, due to the sample size there is an increase in the probability of type II errors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Structure-Based and Random Mutagenesis Approaches Increase the Organophosphate-Degrading Activity of a Phosphotriesterase Homologue from Deinococcus radiodurans

    Energy Technology Data Exchange (ETDEWEB)

    Hawwa, Renda; Larsen, Sonia D.; Ratia, Kiira; Mesecar, Andrew D.; (UIC)

    2010-11-09

    An enzyme from the amidohydrolase family from Deinococcus radiodurans (Dr-OPH) with homology to phosphotriesterase has been shown to exhibit activity against both organophosphate (OP) and lactone compounds. We have characterized the physical properties of Dr-OPH and have found it to be a highly thermostable enzyme, remaining active after 3 h of incubation at 60 C and withstanding incubation at temperatures up to 70 C. In addition, it can withstand concentrations of at least 200 mg/mL. These properties make Dr-OPH a promising candidate for development in commercial applications. However, compared to the most widely studied OP-degrading enzyme, that from Pseudomonas diminuta, Dr-OPH has low hydrolytic activity against certain OP substrates. Therefore, we sought to improve the OP-degrading activity of Dr-OPH, specifically toward the pesticides ethyl and methyl paraoxon, using structure-based and random approaches. Site-directed mutagenesis, random mutagenesis, and site-saturation mutagenesis were utilized to increase the OP-degrading activity of Dr-OPH. Out of a screen of more than 30,000 potential mutants, a total of 26 mutant enzymes were purified and characterized kinetically. Crystal structures of w.t. Dr-OPH, of Dr-OPH in complex with a product analog, and of 7 mutant enzymes were determined to resolutions between 1.7 and 2.4 {angstrom}. Information from these structures directed the design and production of 4 additional mutants for analysis. In total, our mutagenesis efforts improved the catalytic activity of Dr-OPH toward ethyl and methyl paraoxon by 126- and 322-fold and raised the specificity for these two substrates by 557- and 183-fold, respectively. Our work highlights the importance of an iterative approach to mutagenesis, proving that large rate enhancements are achieved when mutations are made in already active mutants. In addition, the relationship between the kinetic parameters and the introduced mutations has allowed us to hypothesize on those

  3. Low-Quality Structural and Interaction Data Improves Binding Affinity Prediction via Random Forest

    Directory of Open Access Journals (Sweden)

    Hongjian Li

    2015-06-01

    Full Text Available Docking scoring functions can be used to predict the strength of protein-ligand binding. It is widely believed that training a scoring function with low-quality data is detrimental for its predictive performance. Nevertheless, there is a surprising lack of systematic validation experiments in support of this hypothesis. In this study, we investigated to which extent training a scoring function with data containing low-quality structural and binding data is detrimental for predictive performance. We actually found that low-quality data is not only non-detrimental, but beneficial for the predictive performance of machine-learning scoring functions, though the improvement is less important than that coming from high-quality data. Furthermore, we observed that classical scoring functions are not able to effectively exploit data beyond an early threshold, regardless of its quality. This demonstrates that exploiting a larger data volume is more important for the performance of machine-learning scoring functions than restricting to a smaller set of higher data quality.

  4. Quantum steganography using prior entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Takashi, E-mail: mihara@toyo.jp

    2015-06-05

    Steganography is the hiding of secret information within innocent-looking information (e.g., text, audio, image, video, etc.). A quantum version of steganography is a method based on quantum physics. In this paper, we propose quantum steganography by combining quantum error-correcting codes with prior entanglement. In many steganographic techniques, embedding secret messages in error-correcting codes may cause damage to them if the embedded part is corrupted. However, our proposed steganography can separately create secret messages and the content of cover messages. The intrinsic form of the cover message does not have to be modified for embedding secret messages. - Highlights: • Our steganography combines quantum error-correcting codes with prior entanglement. • Our steganography can separately create secret messages and the content of cover messages. • Errors in cover messages do not have affect the recovery of secret messages. • We embed a secret message in the Steane code as an example of our steganography.

  5. Effect of Prior Knowledge of Instructional Objectives on Students ...

    African Journals Online (AJOL)

    The study examined the effect of prior knowledge of instructional objectives on students' achievement in selected difficult concepts in senior secondary school physics. A total of 100 senior secondary two (SS II) physics students were involved in the study. A non-randomized pretest-posttest control group design was used.

  6. Prior-to-Exam: What Activities Enhance Performance?

    Science.gov (United States)

    Rhoads, C. J.; Healy, Therese

    2013-01-01

    Can instructors impact their student performance by recommending an activity just prior to taking an exam? In this study, college students were randomly assigned to one of three treatment groups (study, exercise, or meditation) or a control group. Each group was given two different types of tests; a traditional concept exam, and a non-traditional…

  7. Effect of Structured and Unstructured Physical Activity Training on Cognitive Functions in Adolescents - A Randomized Control Trial.

    Science.gov (United States)

    Subramanian, Senthil Kumar; Sharma, Vivek Kumar; Arunachalam, Vinayathan; Radhakrishnan, Krishnakumar; Ramamurthy, Sarah

    2015-11-01

    Regular physical activity in children and adolescents promotes not only their physical health but also improves their cognition. Paper and pencil Neurocognitive tests (NCT) are commonly used to assess the various cognitive domains of a person and can be used as simple tests to assess improvements, if any, in the cognitive abilities of growing adolescents who practice regular physical activity. To study the effect of six months of structured and unstructured physical activity on cognitive functions in adolescents. We recruited 439 healthy adolescent volunteers in the age group of 12 to 17 years (boys 250, girls 189) from a residential school (Jawahar Navodaya Vidyalaya, Pondicherry). The following paper and pencil neuropsychological cognitive tests were administered: Two Target Letter Cancellation test, Trail Making test A and B, Ruff Figural Fluency test (RFFT). These participants were then divided into Structured Physical Activity (SPA: n=219; boys 117, girls 102) and Unstructured Physical Activity (USPA: n=220; boys 119, girls 101) groups based on age and gender block randomization method. Six-month intervention was successfully completed by 347 participants only (SPA group: n= 136; boys 77, girls 59; USPA group: n = 139; boys 75, girls 64) and the tests were repeated. The data were recorded and statistically analysed by per-protocol analysis method, using the Statistical Package for Social Sciences (SPSS), version 19. After six months of intervention, both SPA and USPA group participants showed significant improvements in all the tested neurocognitive parameters. On inter-group comparison, participants in SPA group showed significantly better improvements. Physical activity training in adolescents is more beneficial when structured as per WHO guidelines, probably due to higher cognitive loading.

  8. Multiple Volume Scattering in Random Media and Periodic Structures with Applications in Microwave Remote Sensing and Wave Functional Materials

    Science.gov (United States)

    Tan, Shurun

    The objective of my research is two-fold: to study wave scattering phenomena in dense volumetric random media and in periodic wave functional materials. For the first part, the goal is to use the microwave remote sensing technique to monitor water resources and global climate change. Towards this goal, I study the microwave scattering behavior of snow and ice sheet. For snowpack scattering, I have extended the traditional dense media radiative transfer (DMRT) approach to include cyclical corrections that give rise to backscattering enhancements, enabling the theory to model combined active and passive observations of snowpack using the same set of physical parameters. Besides DMRT, a fully coherent approach is also developed by solving Maxwell's equations directly over the entire snowpack including a bottom half space. This revolutionary new approach produces consistent scattering and emission results, and demonstrates backscattering enhancements and coherent layer effects. The birefringence in anisotropic snow layers is also analyzed by numerically solving Maxwell's equation directly. The effects of rapid density fluctuations in polar ice sheet emission in the 0.5˜2.0 GHz spectrum are examined using both fully coherent and partially coherent layered media emission theories that agree with each other and distinct from incoherent approaches. For the second part, the goal is to develop integral equation based methods to solve wave scattering in periodic structures such as photonic crystals and metamaterials that can be used for broadband simulations. Set upon the concept of modal expansion of the periodic Green's function, we have developed the method of broadband Green's function with low wavenumber extraction (BBGFL), where a low wavenumber component is extracted and results a non-singular and fast-converging remaining part with simple wavenumber dependence. We've applied the technique to simulate band diagrams and modal solutions of periodic structures, and to

  9. Carbon nanotubes randomly decorated with gold clusters: from nano{sup 2}hybrid atomic structures to gas sensing prototypes

    Energy Technology Data Exchange (ETDEWEB)

    Charlier, J-C; Zanolli, Z [Unite de Physico-Chimie et de Physique des Materiaux (PCPM), European Theoretical Spectroscopy Facility (ETSF), Universite Catholique de Louvain, Place Croix du Sud 1, B-1348 Louvain-la-Neuve (Belgium); Arnaud, L; Avilov, I V; Felten, A; Pireaux, J-J [Centre de Recherche en Physique de la Matiere et du Rayonnement (PMR-LISE), Facultes Universitaires Notre-Dame de la Paix, 61 Rue de Bruxelles, B-5000 Namur (Belgium); Delgado, M [Sensotran, s.l., Avenida Remolar 31, E-08820 El Prat de Llobregat, Barcelona (Spain); Demoisson, F; Reniers, F [Service de Chimie Analytique et Chimie des Interfaces (CHANI), Universite Libre de Bruxelles, Faculte des Sciences, CP255, Boulevard du Triomphe 2, B-1050 Bruxelles (Belgium); Espinosa, E H; Ionescu, R; Leghrib, R; Llobet, E [Department of Electronic Engineering, Universitat Rovira i Virgili, Avenida Paisos Catalans 26, E-43007 Tarragona (Spain); Ewels, C P; Suarez-Martinez, I [Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes, 2 rue de la Houssiniere-BP 32229, F-44322 Nantes Cedex 3 (France); Guillot, J; Mansour, A; Migeon, H-N [Departement Science et Analyse des Materiaux, Centre de Recherche Public-Gabriel Lippmann, rue du Brill 41, L-4422 Belvaux (Luxembourg); Watson, G E, E-mail: jean-jacques.pireaux@fundp.ac.b [Vega Science Trust, Unit 118, Science Park SQ, Brighton, BN1 9SB (United Kingdom)

    2009-09-16

    Carbon nanotube surfaces, activated and randomly decorated with metal nanoclusters, have been studied in uniquely combined theoretical and experimental approaches as prototypes for molecular recognition. The key concept is to shape metallic clusters that donate or accept a fractional charge upon adsorption of a target molecule, and modify the electron transport in the nanotube. The present work focuses on a simple system, carbon nanotubes with gold clusters. The nature of the gold-nanotube interaction is studied using first-principles techniques. The numerical simulations predict the binding and diffusion energies of gold atoms at the tube surface, including realistic atomic models for defects potentially present at the nanotube surface. The atomic structure of the gold nanoclusters and their effect on the intrinsic electronic quantum transport properties of the nanotube are also predicted. Experimentally, multi-wall CNTs are decorated with gold clusters using (1) vacuum evaporation, after activation with an RF oxygen plasma and (2) colloid solution injected into an RF atmospheric plasma; the hybrid systems are accurately characterized using XPS and TEM techniques. The response of gas sensors based on these nano{sup 2}hybrids is quantified for the detection of toxic species like NO{sub 2}, CO, C{sub 2}H{sub 5}OH and C{sub 2}H{sub 4}.

  10. Causal Inference for Meta-Analysis and Multi-Level Data Structures, with Application to Randomized Studies of Vioxx.

    Science.gov (United States)

    Sobel, Michael; Madigan, David; Wang, Wei

    2017-06-01

    We construct a framework for meta-analysis and other multi-level data structures that codifies the sources of heterogeneity between studies or settings in treatment effects and examines their implications for analyses. The key idea is to consider, for each of the treatments under investigation, the subject's potential outcome in each study or setting were he to receive that treatment. We consider four sources of heterogeneity: (1) response inconsistency, whereby a subject's response to a given treatment would vary across different studies or settings, (2) the grouping of nonequivalent treatments, where two or more treatments are grouped and treated as a single treatment under the incorrect assumption that a subject's responses to the different treatments would be identical, (3) nonignorable treatment assignment, and (4) response-related variability in the composition of subjects in different studies or settings. We then examine how these sources affect heterogeneity/homogeneity of conditional and unconditional treatment effects. To illustrate the utility of our approach, we re-analyze individual participant data from 29 randomized placebo-controlled studies on the cardiovascular risk of Vioxx, a Cox-2 selective nonsteroidal anti-inflammatory drug approved by the FDA in 1999 for the management of pain and withdrawn from the market in 2004.

  11. Can dialectical behavior therapy be learned in highly structured learning environments? Results from a randomized controlled dissemination trial.

    Science.gov (United States)

    Dimeff, Linda A; Woodcock, Eric A; Harned, Melanie S; Beadnell, Blair

    2011-06-01

    This study evaluated the efficacy of methods of training community mental health providers (N=132) in dialectical behavior therapy (DBT) distress tolerance skills, including (a) Linehan's (1993a) Skills Training Manual for Borderline Personality Disorder (Manual), (b) a multimedia e-Learning course covering the same content (e-DBT), and (c) a placebo control e-Learning course (e-Control). Participants were randomized to a condition, and the training took place in a highly structured and controlled learning environment. Assessments were completed at baseline, post-training, and 2, 7, 11, and 15 weeks following training. The results indicate that one or both of the active DBT conditions outperformed the control condition on all outcomes except motivation to learn and use the treatment. While clinicians preferred e-DBT over the Manual and found it more helpful and engaging, the active DBT conditions generally did not differ on the primary outcomes of knowledge and self-efficacy, with the exception that e-DBT significantly outperformed the Manual on knowledge at the 15-week follow-up. E-DBT also produced the highest rate of applying and teaching the newly learned skills in clinical practice. Overall, results from this study support the efficacy of e-Learning in disseminating knowledge of empirically supported treatments to clinicians, while also indicating that treatment manuals can be effective training tools. Copyright © 2011. Published by Elsevier Ltd.

  12. Carbon nanotubes randomly decorated with gold clusters: from nano2hybrid atomic structures to gas sensing prototypes.

    Science.gov (United States)

    Charlier, J-C; Arnaud, L; Avilov, I V; Delgado, M; Demoisson, F; Espinosa, E H; Ewels, C P; Felten, A; Guillot, J; Ionescu, R; Leghrib, R; Llobet, E; Mansour, A; Migeon, H-N; Pireaux, J-J; Reniers, F; Suarez-Martinez, I; Watson, G E; Zanolli, Z

    2009-09-16

    Carbon nanotube surfaces, activated and randomly decorated with metal nanoclusters, have been studied in uniquely combined theoretical and experimental approaches as prototypes for molecular recognition. The key concept is to shape metallic clusters that donate or accept a fractional charge upon adsorption of a target molecule, and modify the electron transport in the nanotube. The present work focuses on a simple system, carbon nanotubes with gold clusters. The nature of the gold-nanotube interaction is studied using first-principles techniques. The numerical simulations predict the binding and diffusion energies of gold atoms at the tube surface, including realistic atomic models for defects potentially present at the nanotube surface. The atomic structure of the gold nanoclusters and their effect on the intrinsic electronic quantum transport properties of the nanotube are also predicted. Experimentally, multi-wall CNTs are decorated with gold clusters using (1) vacuum evaporation, after activation with an RF oxygen plasma and (2) colloid solution injected into an RF atmospheric plasma; the hybrid systems are accurately characterized using XPS and TEM techniques. The response of gas sensors based on these nano(2)hybrids is quantified for the detection of toxic species like NO(2), CO, C(2)H(5)OH and C(2)H(4).

  13. Market Correlation Structure Changes Around the Great Crash: A Random Matrix Theory Analysis of the Chinese Stock Market

    Science.gov (United States)

    Han, Rui-Qi; Xie, Wen-Jie; Xiong, Xiong; Zhang, Wei; Zhou, Wei-Xing

    The correlation structure of a stock market contains important financial contents, which may change remarkably due to the occurrence of financial crisis. We perform a comparative analysis of the Chinese stock market around the occurrence of the 2008 crisis based on the random matrix analysis of high-frequency stock returns of 1228 Chinese stocks. Both raw correlation matrix and partial correlation matrix with respect to the market index in two time periods of one year are investigated. We find that the Chinese stocks have stronger average correlation and partial correlation in 2008 than in 2007 and the average partial correlation is significantly weaker than the average correlation in each period. Accordingly, the largest eigenvalue of the correlation matrix is remarkably greater than that of the partial correlation matrix in each period. Moreover, each largest eigenvalue and its eigenvector reflect an evident market effect, while other deviating eigenvalues do not. We find no evidence that deviating eigenvalues contain industrial sectorial information. Surprisingly, the eigenvectors of the second largest eigenvalues in 2007 and of the third largest eigenvalues in 2008 are able to distinguish the stocks from the two exchanges. We also find that the component magnitudes of the some largest eigenvectors are proportional to the stocks’ capitalizations.

  14. Structural Integration as an Adjunct to Outpatient Rehabilitation for Chronic Nonspecific Low Back Pain: A Randomized Pilot Clinical Trial

    Directory of Open Access Journals (Sweden)

    Eric E. Jacobson

    2015-01-01

    Full Text Available Structural Integration (SI is an alternative method of manipulation and movement education. To obtain preliminary data on feasibility, effectiveness, and adverse events (AE, 46 outpatients from Boston area with chronic nonspecific low back pain (CNSLBP were randomized to parallel treatment groups of SI plus outpatient rehabilitation (OR versus OR alone. Feasibility data were acceptable except for low compliance with OR and lengthy recruitment time. Intent-to-treat data on effectiveness were analyzed by Wilcoxon rank sum, n=23 per group. Median reductions in VAS Pain, the primary outcome, of -26 mm in SI + OR versus 0 in OR alone were not significantly different (P=0.075. Median reductions in RMDQ, the secondary outcome, of -2 points in SI + OR versus 0 in OR alone were significantly different (P=0.007. Neither the proportions of participants with nor the seriousness of AE were significantly different. SI as an adjunct to OR for CNSLBP is not likely to provide additional reductions in pain but is likely to augment short term improvements in disability with a low additional burden of AE. A more definitive trial is feasible, but OR compliance and recruitment might be challenging. This trial is registered with ClinicalTrials.gov (NCT01322399.

  15. Galvanic deposition of Rh and Ru on randomly structured Ti felts for the electrochemical NH3 synthesis.

    Science.gov (United States)

    Kugler, Kurt; Luhn, Mareike; Schramm, Jean André; Rahimi, Khosrow; Wessling, Matthias

    2015-02-07

    Nowadays NH3 is exclusively synthesized by the Haber process. Unfortunately, the energy demand and the CO2 emissions due to H2 production are high. Hydrogen production utilizes precious carbon sources such as coal and natural gas. In the past we proposed an alternative process concept using a membrane electrode assembly in an electrochemical membrane reactor (ecMR). At the anode H2O is oxidized at an IrMMO catalyst to form protons. By applying an external potential to the ecMR N2 is reduced to NH3 at the cathode. Just recently Rh and Ru were identified as possible cathodic electrocatalysts by DFT calculations. We present an easy and highly efficient method for galvanic coatings of Rh and Ru on randomly structured Ti felts to be used in a membrane electrode assembly. Linear sweep voltammetry measurements give a slightly higher activity of Ru for the liquid phase electrochemical NH3 synthesis. The NH4(+) concentration reached is 8 times higher for Ru than for Rh. From an economical point of view, Ru is also more feasible for an electrochemical NH3 synthesis process. Such electrodes can now be evaluated in an ecMR in comparison to recently demonstrated Ti-based electrodes.

  16. Receptive field inference with localized priors.

    Directory of Open Access Journals (Sweden)

    Mijung Park

    2011-10-01

    Full Text Available The linear receptive field describes a mapping from sensory stimuli to a one-dimensional variable governing a neuron's spike response. However, traditional receptive field estimators such as the spike-triggered average converge slowly and often require large amounts of data. Bayesian methods seek to overcome this problem by biasing estimates towards solutions that are more likely a priori, typically those with small, smooth, or sparse coefficients. Here we introduce a novel Bayesian receptive field estimator designed to incorporate locality, a powerful form of prior information about receptive field structure. The key to our approach is a hierarchical receptive field model that flexibly adapts to localized structure in both spacetime and spatiotemporal frequency, using an inference method known as empirical Bayes. We refer to our method as automatic locality determination (ALD, and show that it can accurately recover various types of smooth, sparse, and localized receptive fields. We apply ALD to neural data from retinal ganglion cells and V1 simple cells, and find it achieves error rates several times lower than standard estimators. Thus, estimates of comparable accuracy can be achieved with substantially less data. Finally, we introduce a computationally efficient Markov Chain Monte Carlo (MCMC algorithm for fully Bayesian inference under the ALD prior, yielding accurate Bayesian confidence intervals for small or noisy datasets.

  17. Features of surfaces with random structure variations: Poster at Strategic Workshop "Principles and Development of Bio-Inspired Materials", 13 - 15 April 2010; Vienna, Austria

    OpenAIRE

    Mölders, N.; Nellesen, A.; Bertling, J.

    2010-01-01

    In contrast to the precision requested in industrial processing, biological structures only seem to possess a perfect, uniform regularity. Within the recurring patterns and periodic self-similar structures a randomly acting variation appears to be present. The main goal of this work is to elucidate whether these variations are irrelevant or related to the particular functionality of a surface or if they are just a result of stimulus- environmental interaction and genetical predisposition. The...

  18. A shape prior-based MRF model for 3D masseter muscle segmentation

    Science.gov (United States)

    Majeed, Tahir; Fundana, Ketut; Lüthi, Marcel; Beinemann, Jörg; Cattin, Philippe

    2012-02-01

    Medical image segmentation is generally an ill-posed problem that can only be solved by incorporating prior knowledge. The ambiguities arise due to the presence of noise, weak edges, imaging artifacts, inhomogeneous interior and adjacent anatomical structures having similar intensity profile as the target structure. In this paper we propose a novel approach to segment the masseter muscle using the graph-cut incorporating additional 3D shape priors in CT datasets, which is robust to noise; artifacts; and shape deformations. The main contribution of this paper is in translating the 3D shape knowledge into both unary and pairwise potentials of the Markov Random Field (MRF). The segmentation task is casted as a Maximum-A-Posteriori (MAP) estimation of the MRF. Graph-cut is then used to obtain the global minimum which results in the segmentation of the masseter muscle. The method is tested on 21 CT datasets of the masseter muscle, which are noisy with almost all possessing mild to severe imaging artifacts such as high-density artifacts caused by e.g. the very common dental fillings and dental implants. We show that the proposed technique produces clinically acceptable results to the challenging problem of muscle segmentation, and further provide a quantitative and qualitative comparison with other methods. We statistically show that adding additional shape prior into both unary and pairwise potentials can increase the robustness of the proposed method in noisy datasets.

  19. Testing Small Variance Priors Using Prior-Posterior Predictive p Values.

    Science.gov (United States)

    Hoijtink, Herbert; van de Schoot, Rens

    2017-04-03

    Muthén and Asparouhov (2012) propose to evaluate model fit in structural equation models based on approximate (using small variance priors) instead of exact equality of (combinations of) parameters to zero. This is an important development that adequately addresses Cohen's (1994) The Earth is Round (p < .05), which stresses that point null-hypotheses are so precise that small and irrelevant differences from the null-hypothesis may lead to their rejection. It is tempting to evaluate small variance priors using readily available approaches like the posterior predictive p value and the DIC. However, as will be shown, both are not suited for the evaluation of models based on small variance priors. In this article, a well behaving alternative, the prior-posterior predictive p value, will be introduced. It will be shown that it is consistent, the distributions under the null and alternative hypotheses will be elaborated, and it will be applied to testing whether the difference between 2 means and the size of a correlation are relevantly different from zero. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  20. Gaussian-like spatial priors for articulated tracking

    DEFF Research Database (Denmark)

    Hauberg, Søren; Sommer, Stefan Horst; Pedersen, Kim Steenstrup

    2010-01-01

    We present an analysis of the spatial covariance structure of an articulated motion prior in which joint angles have a known covariance structure. From this, a well-known, but often ignored, deficiency of the kinematic skeleton representation becomes clear: spatial variance not only depends on limb...

  1. Least squares estimation without priors or supervision.

    Science.gov (United States)

    Raphan, Martin; Simoncelli, Eero P

    2011-02-01

    Selection of an optimal estimator typically relies on either supervised training samples (pairs of measurements and their associated true values) or a prior probability model for the true values. Here, we consider the problem of obtaining a least squares estimator given a measurement process with known statistics (i.e., a likelihood function) and a set of unsupervised measurements, each arising from a corresponding true value drawn randomly from an unknown distribution. We develop a general expression for a nonparametric empirical Bayes least squares (NEBLS) estimator, which expresses the optimal least squares estimator in terms of the measurement density, with no explicit reference to the unknown (prior) density. We study the conditions under which such estimators exist and derive specific forms for a variety of different measurement processes. We further show that each of these NEBLS estimators may be used to express the mean squared estimation error as an expectation over the measurement density alone, thus generalizing Stein's unbiased risk estimator (SURE), which provides such an expression for the additive gaussian noise case. This error expression may then be optimized over noisy measurement samples, in the absence of supervised training data, yielding a generalized SURE-optimized parametric least squares (SURE2PLS) estimator. In the special case of a linear parameterization (i.e., a sum of nonlinear kernel functions), the objective function is quadratic, and we derive an incremental form for learning this estimator from data. We also show that combining the NEBLS form with its corresponding generalized SURE expression produces a generalization of the score-matching procedure for parametric density estimation. Finally, we have implemented several examples of such estimators, and we show that their performance is comparable to their optimal Bayesian or supervised regression counterparts for moderate to large amounts of data.

  2. Validation of a structured training and assessment curriculum for technical skill acquisition in minimally invasive surgery: a randomized controlled trial.

    Science.gov (United States)

    Palter, Vanessa N; Orzech, Neil; Reznick, Richard K; Grantcharov, Teodor P

    2013-02-01

    : To develop and validate an ex vivo comprehensive curriculum for a basic laparoscopic procedure. : Although simulators have been well validated as tools to teach technical skills, their integration into comprehensive curricula is lacking. Moreover, neither the effect of ex vivo training on learning curves in the operating room (OR), nor the effect on nontechnical proficiency has been investigated. : This randomized single-blinded prospective trial allocated 20 surgical trainees to a structured training and assessment curriculum (STAC) group or conventional residency training. The STAC consisted of case-based learning, proficiency-based virtual reality training, laparoscopic box training, and OR participation. After completion of the intervention, all participants performed 5 sequential laparoscopic cholecystectomies in the OR. The primary outcome measure was the difference in technical performance between the 2 groups during the first laparoscopic cholecystectomy. Secondary outcome measures included differences with respect to learning curves in the OR, technical proficiency of each sequential laparoscopic cholecystectomy, and nontechnical skills. : Residents in the STAC group outperformed residents in the conventional group in the first (P = 0.004), second (P = 0.036), third (P = 0.021), and fourth (P = 0.023) laparoscopic cholecystectomies. The conventional group demonstrated a significant learning curve in the OR (P = 0.015) in contrast to the STAC group (P = 0.032). Residents in the STAC group also had significantly higher nontechnical skills (P = 0.027). : Participating in the STAC shifted the learning curve for a basic laparoscopic procedure from the operating room into the simulation laboratory. STAC-trained residents had superior technical proficiency in the OR and nontechnical skills compared with conventionally trained residents. (The study registration ID is NCT01560494.).

  3. Prediction of conformational B-cell epitopes from 3D structures by random forests with a distance-based feature.

    Science.gov (United States)

    Zhang, Wen; Xiong, Yi; Zhao, Meng; Zou, Hua; Ye, Xinghuo; Liu, Juan

    2011-08-17

    Antigen-antibody interactions are key events in immune system, which provide important clues to the immune processes and responses. In Antigen-antibody interactions, the specific sites on the antigens that are directly bound by the B-cell produced antibodies are well known as B-cell epitopes. The identification of epitopes is a hot topic in bioinformatics because of their potential use in the epitope-based drug design. Although most B-cell epitopes are discontinuous (or conformational), insufficient effort has been put into the conformational epitope prediction, and the performance of existing methods is far from satisfaction. In order to develop the high-accuracy model, we focus on some possible aspects concerning the prediction performance, including the impact of interior residues, different contributions of adjacent residues, and the imbalanced data which contain much more non-epitope residues than epitope residues. In order to address above issues, we take following strategies. Firstly, a concept of 'thick surface patch' instead of 'surface patch' is introduced to describe the local spatial context of each surface residue, which considers the impact of interior residue. The comparison between the thick surface patch and the surface patch shows that interior residues contribute to the recognition of epitopes. Secondly, statistical significance of the distance distribution difference between non-epitope patches and epitope patches is observed, thus an adjacent residue distance feature is presented, which reflects the unequal contributions of adjacent residues to the location of binding sites. Thirdly, a bootstrapping and voting procedure is adopted to deal with the imbalanced dataset. Based on the above ideas, we propose a new method to identify the B-cell conformational epitopes from 3D structures by combining conventional features and the proposed feature, and the random forest (RF) algorithm is used as the classification engine. The experiments show that our

  4. Prediction of conformational B-cell epitopes from 3D structures by random forests with a distance-based feature

    Directory of Open Access Journals (Sweden)

    Zou Hua

    2011-08-01

    Full Text Available Abstract Background Antigen-antibody interactions are key events in immune system, which provide important clues to the immune processes and responses. In Antigen-antibody interactions, the specific sites on the antigens that are directly bound by the B-cell produced antibodies are well known as B-cell epitopes. The identification of epitopes is a hot topic in bioinformatics because of their potential use in the epitope-based drug design. Although most B-cell epitopes are discontinuous (or conformational, insufficient effort has been put into the conformational epitope prediction, and the performance of existing methods is far from satisfaction. Results In order to develop the high-accuracy model, we focus on some possible aspects concerning the prediction performance, including the impact of interior residues, different contributions of adjacent residues, and the imbalanced data which contain much more non-epitope residues than epitope residues. In order to address above issues, we take following strategies. Firstly, a concept of 'thick surface patch' instead of 'surface patch' is introduced to describe the local spatial context of each surface residue, which considers the impact of interior residue. The comparison between the thick surface patch and the surface patch shows that interior residues contribute to the recognition of epitopes. Secondly, statistical significance of the distance distribution difference between non-epitope patches and epitope patches is observed, thus an adjacent residue distance feature is presented, which reflects the unequal contributions of adjacent residues to the location of binding sites. Thirdly, a bootstrapping and voting procedure is adopted to deal with the imbalanced dataset. Based on the above ideas, we propose a new method to identify the B-cell conformational epitopes from 3D structures by combining conventional features and the proposed feature, and the random forest (RF algorithm is used as the

  5. A quasi-linear structure of the southern margin of Eurasia prior to the India-Asia collision: First paleomagnetic constraints from Upper Cretaceous volcanic rocks near the western syntaxis of Tibet

    Science.gov (United States)

    Yi, Zhiyu; Huang, Baochun; Yang, Liekun; Tang, Xiangde; Yan, Yonggang; Qiao, Qingqing; Zhao, Jie; Chen, Liwei

    2015-07-01

    We report the first combined geochronologic and paleomagnetic study of volcanic rocks from the Shiquanhe and Yare Basins at the westernmost Lhasa Terrane, which aims to provide an accurate constraint on the shape and paleoposition of the southern margin of Asia prior to the India-Asia collision. Three new 40Ar/39Ar ages of 92.5 ± 2.9 Ma, 92.4 ± 0.9 Ma, and 79.6 ± 0.7 Ma determined by fresh matrix or feldspar from lava flows suggest a Late Cretaceous age for the investigated units. Characteristic remanent magnetizations have been successfully isolated from 38 sites which pass positive fold and/or reversal, conglomerate tests and are hence interpreted as primary in origin. The two paleopoles obtained from Yare and Shiquanhe yield consistent paleolatitudes of 13.6°N ± 9.6°N and 14.2°N ± 2.7°N, respectively (for a reference site of 31.5°N, 80°E), indicating that the southern margin of Asia near the western syntaxis was located far south during the Late Cretaceous time. A reconstruction of the Lhasa Terrane in the frame of Eurasia with paleomagnetic data obtained from its western and eastern parts indicates that the southern margin of Eurasia probably had a quasi-linear orientation prior to the collision formerly trending approximately 315°E. This is compatible with the shape of the Neo-Tethys slab observed from seismic tomographic studies. Our findings provide a solid basis for evaluating Cenozoic crustal shortening in the Asian interior and the size of Greater India near the western syntaxis.

  6. Bayesian Regression with Network Prior: Optimal Bayesian Filtering Perspective.

    Science.gov (United States)

    Qian, Xiaoning; Dougherty, Edward R

    2016-12-01

    The recently introduced intrinsically Bayesian robust filter (IBRF) provides fully optimal filtering relative to a prior distribution over an uncertainty class ofjoint random process models, whereas formerly the theory was limited to model-constrained Bayesian robust filters, for which optimization was limited to the filters that are optimal for models in the uncertainty class. This paper extends the IBRF theory to the situation where there are both a prior on the uncertainty class and sample data. The result is optimal Bayesian filtering (OBF), where optimality is relative to the posterior distribution derived from the prior and the data. The IBRF theories for effective characteristics and canonical expansions extend to the OBF setting. A salient focus of the present work is to demonstrate the advantages of Bayesian regression within the OBF setting over the classical Bayesian approach in the context otlinear Gaussian models.

  7. Does pragmatically structured outpatient dietary counselling reduce sodium intake in hypertensive patients? Study protocol for a randomized controlled trial.

    Science.gov (United States)

    Ruzicka, Marcel; Ramsay, Tim; Bugeja, Ann; Edwards, Cedric; Fodor, George; Kirby, Anne; Magner, Peter; McCormick, Brendan; van der Hoef, Gigi; Wagner, Jessica; Hiremath, Swapnil

    2015-06-17

    Hypertension is highly prevalent among adults, and is the most important modifiable risk factor for cardiovascular events, in particular stroke. Decreasing sodium intake has the potential to prevent or delay the development of hypertension and improve blood pressure control, independently of blood pressure lowering drugs, among hypertensive patients. Despite guidelines recommending a low sodium diet, especially for hypertensive individuals, sodium intake remains higher than recommended. A recent systematic review indicated that the efficacious counselling methods described in published trials are not suitable for hypertension management by primary care providers in Canada in the present form. The primary reason for the lack of feasibility is that interventions for sodium restriction in these trials was not limited to counselling, but included provision of food, prepared meals, or intensive inpatient training sessions. This is a parallel, randomized, controlled, open-label trial with blinded endpoints. Inclusion criteria are adult patients with hypertension with high dietary sodium intake (defined as ≥ 100 mmol/day). The control arm will receive usual care, and the intervention arm will receive usual care and an additional structured counselling session by a registered dietitian, with four follow-up telephone support sessions over four weeks. The two primary outcomes are change in sodium intake from baseline, as measured by a change in 24-hour urinary sodium measurements at four weeks and one year. Secondary outcomes include change in blood pressure (as measured by 24-hour ambulatory monitoring), change in 24-hour urinary potassium, and change in body weight at the same time points. Though decreasing sodium intake has been reported to be efficacious in lowering blood pressure, there exists a gap in the evidence for an effective intervention that could be easily translated into clinical practice. If successful, our intervention would be suitable for outpatient

  8. Imaging gastric structuring of lipid emulsions and its effect on gastrointestinal function: a randomized trial in healthy subjects.

    Science.gov (United States)

    Steingoetter, Andreas; Radovic, Tijana; Buetikofer, Simon; Curcic, Jelena; Menne, Dieter; Fried, Michael; Schwizer, Werner; Wooster, Tim J

    2015-04-01

    Efficient fat digestion requires fat processing within the stomach and fat sensing in the intestine. Both processes also control gastric emptying and gastrointestinal secretions. We aimed to visualize the influence of the intragastric stability of fat emulsions on their dynamics of gastric processing and structuring and to assess the effect this has on gastrointestinal motor and secretory functions. Eighteen healthy subjects with normal body mass index (BMI) were studied on 4 separate occasions in a double-blind, randomized, crossover design. Magnetic resonance imaging (MRI) data of the gastrointestinal tract and blood triglycerides were recorded before and for 240 min after the consumption of the following 4 different fat emulsions: lipid emulsion 1 (LE1; acid stable, 0.33 μm), lipid emulsion 2 (LE2; acid stable, 52 μm), lipid emulsion 3 (LE3; acid unstable, solid fat, 0.32 μm), and lipid emulsion 4 (LE4; acid unstable, liquid fat, 0.38 μm). Intragastric emulsion instability was associated with a change in gastric emptying. Acid-unstable emulsions exhibited biphasic and faster emptying profiles than did the 2 acid-stable emulsions (P ≤ 0.0001). When combined with solid fat (LE3), different dynamics of postprandial gallbladder volume were induced (P ≤ 0.001). For acid-stable emulsions, a reduction of droplet size by 2 orders of magnitude [LE1 (0.33 μm) compared with LE2 (52 μm)] delayed gastric emptying by 38 min. Although acid-stable (LE1 and LE2) and redispersible (LE4) emulsions caused a constant increase in blood triglycerides, no increase was detectable for LE3 (P emulsions. The acute effects of lipid emulsions on gastric emptying, gallbladder volume, and triglyceride absorption are dependent on microstructural changes undergone during consumption. Gastric peristalsis and secretion were effective at redispersing pools of liquid fat in the stomach. This trial was registered at clinicaltrials.gov as NCT01253005. © 2015 American Society for Nutrition.

  9. Prior knowledge and entrepreneurial innovative success

    OpenAIRE

    Cantner, Uwe; Goethner, Maximilian; Meder, Andreas

    2007-01-01

    This paper is concerned with the relationship between innovative success of entrepreneurs and their prior knowledge at the stage of firm formation. We distinguish between different kinds of experience an entrepreneur can possess and find evidence that the innovative success subsequent to firm formation is enhanced by entrepreneur’s prior technological knowledge but not by prior market and organizational knowledge. Moreover we find that prior technological knowledge gathered through embeddedne...

  10. Hippocampus segmentation using locally weighted prior based level set

    Science.gov (United States)

    Achuthan, Anusha; Rajeswari, Mandava

    2015-12-01

    Segmentation of hippocampus in the brain is one of a major challenge in medical image segmentation due to its' imaging characteristics, with almost similar intensity between another adjacent gray matter structure, such as amygdala. The intensity similarity has causes the hippocampus to have weak or fuzzy boundaries. With this main challenge being demonstrated by hippocampus, a segmentation method that relies on image information alone may not produce accurate segmentation results. Therefore, it is needed an assimilation of prior information such as shape and spatial information into existing segmentation method to produce the expected segmentation. Previous studies has widely integrated prior information into segmentation methods. However, the prior information has been utilized through a global manner integration, and this does not reflect the real scenario during clinical delineation. Therefore, in this paper, a locally integrated prior information into a level set model is presented. This work utilizes a mean shape model to provide automatic initialization for level set evolution, and has been integrated as prior information into the level set model. The local integration of edge based information and prior information has been implemented through an edge weighting map that decides at voxel level which information need to be observed during a level set evolution. The edge weighting map shows which corresponding voxels having sufficient edge information. Experiments shows that the proposed integration of prior information locally into a conventional edge-based level set model, known as geodesic active contour has shown improvement of 9% in averaged Dice coefficient.

  11. Experimental Evidence on Valuation with Multiple Priors

    NARCIS (Netherlands)

    Qiu, J.; Weitzel, G.U.

    2016-01-01

    Popular models for decision making under ambiguity assume that people use not one but multiple priors. This paper is a first attempt to experimentally elicit the min and the max of multiple priors directly. In an ambiguous scenario we measure a participant’s single prior, her min and max of multiple

  12. Asymptotically informative prior for Bayesian analysis

    NARCIS (Netherlands)

    Yuan, A.; de Gooijer, J.G.

    2011-01-01

    In classical Bayesian inference the prior is treated as fixed, it is asymptotically negligible, thus any information contained in the prior is ignored from the asymptotic first order result. However, in practice often an informative prior is summarized from previous similar or the same kind of

  13. A Randomized Clinical Trial Comparison Between Pivotal Response Treatment (PRT) and Structured Applied Behavior Analysis (ABA) Intervention for Children with Autism

    OpenAIRE

    Mohammadzaheri, Fereshteh; Koegel, Lynn Kern; Rezaee,Mohammad; Rafiee, Seyed Majid

    2014-01-01

    Accumulating studies are documenting specific motivational variables that, when combined into a naturalistic teaching paradigm, can positively influence the effectiveness of interventions for children with autism spectrum disorder (ASD). The purpose of this study was to compare two ABA intervention procedures, a naturalistic approach, Pivotal Response Treatment (PRT) with a structured ABA approach in a school setting. A Randomized Clinical Trial design using two groups of children, matched ac...

  14. A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures (Preprint)

    Science.gov (United States)

    2018-01-10

    metal -induced gap states to the electronic density of states were identified, accommodating oxygen vacancy states, and showing that the interface region...Electrically switchable resistive random access memories have drawn much interest as nonvolatile memory device candidates, based also metal -insulator... metal (MIM) structure concepts. However, atomic-level mechanisms that lead to conductive filament (CF) formation in MIMs are often lacking, such as

  15. Efficacy of strength and aerobic exercise on patient-reported outcomes and structural changes in patients with knee osteoarthritis: study protocol for a randomized controlled trial

    OpenAIRE

    Øiestad, Britt Elin; Østerås, Nina; Frobell, Richard; Grotle, Margreth; Brøgger, Helga; Risberg, May Arna

    2013-01-01

    Open Access Highly Accessed Study protocol Efficacy of strength and aerobic exercise on patient-reported outcomes and structural changes in patients with knee osteoarthritis: study protocol for a randomized controlled trial Britt Elin Øiestad1*, Nina Østerås2, Richard Frobell3, Margreth Grotle4, Helga Brøgger5 and May Arna Risberg16 * Corresponding author: Britt E Øiestad Author Affiliations 1 Norwegian Research Center for Active Rehabilitation ...

  16. Placenta previa after prior abortion: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Manoochehr Karami

    2017-07-01

    Full Text Available There is controversy regarding the role of prior abortion on placenta previa in subsequent pregnancies. We conducted an updated, comprehensive meta-analysis of placenta previa after prior abortion. The search was conducted from PubMed, Web of Science and Scopus databases from the database inception to January 31, 2017. The heterogeneity across studies was evaluated by Q-test and I2 statistical test. Publication bias was assessed by Begg's test and Egger's test. Results of odds ratio (OR estimates with their corresponding 95% confidence intervals (CI were pooled using random-effects modeling. The literature search included 872 articles up until January 2017 with 2,134,529 participants. Based on OR estimates obtained from case-control and cohort studies, we found a significant association between prior spontaneous abortions and placenta previa (1.77; 95% CI: 1.60, 1.94 and between prior induced abortions and placenta previa (1.36; 95% CI: 1.02, 1.69. The meta-analysis study herein showed that prior abortion is a risk factor for placenta previa.

  17. The generalization of prior uncertainty during reaching.

    Science.gov (United States)

    Fernandes, Hugo L; Stevenson, Ian H; Vilares, Iris; Kording, Konrad P

    2014-08-20

    Bayesian statistics defines how new information, given by a likelihood, should be combined with previously acquired information, given by a prior distribution. Many experiments have shown that humans make use of such priors in cognitive, perceptual, and motor tasks, but where do priors come from? As people never experience the same situation twice, they can only construct priors by generalizing from similar past experiences. Here we examine the generalization of priors over stochastic visuomotor perturbations in reaching experiments. In particular, we look into how the first two moments of the prior--the mean and variance (uncertainty)--generalize. We find that uncertainty appears to generalize differently from the mean of the prior, and an interesting asymmetry arises when the mean and the uncertainty are manipulated simultaneously. Copyright © 2014 the authors 0270-6474/14/3411470-15$15.00/0.

  18. Modified Inflatable Penile Prosthesis Reservoir Placement Into Space of Retzius: Comparing Outcomes in Men With or Without Prior Pelvic Surgery.

    Science.gov (United States)

    Capoccia, Edward M; Phelps, Jessica N; Levine, Laurence A

    2017-07-01

    Traditional inflatable penile prosthesis (IPP) reservoir placement has rare but potentially serious complications including damage to local structures, and Levine and Hoeh (J Sex Med 2012;9:2759-2769) described a modified technique designed to avoid these complications. To determine whether the modified Jorgenson scissors technique is safe and effective in patients who have had prior pelvic surgery. A retrospective chart review was performed on all patients who had a three-piece IPP placed by a single urologist from 2011 to 2015. Complication rates between the prior pelvic surgery group and the virgin pelvis group were compared using χ2 test. Differences between the two groups were considered statistically significant at a P value less than .05. Reservoir-related complication rate and rate of converting to ectopic placement. A total of 246 procedures were included, with 174 having no prior pelvic surgery and 72 with prior pelvic surgery. The reservoir-related complication rates were 2.8% (2 of 72) in the prior pelvic surgery group and 3.4% (6 of 174) in the virgin pelvis group. This difference was not statistically significant (P = .79). The two complications from the prior pelvic surgery cohort were inguinal hernias requiring surgical repair, which occurred in the same patient. In the virgin pelvis cohort, there were five inguinal hernias and one autoinflation. There were 16 patients who required ectopic placement of the reservoir owing to difficulty in entering the space of Retzius (SOR), 14 of whom had prior pelvic surgery. We believe this modified technique for IPP reservoir placement into the SOR is a safe alternative because the Jorgenson scissors allow perforation into the SOR away from vital structures. The study is limited by the fact that it is a retrospective, single-center, chart review of a non-randomized surgical procedure with variable follow-up in a limited number of patients. Its strength is its applicability to provide surgeons a modified

  19. Directional interactions between current and prior saccades

    Directory of Open Access Journals (Sweden)

    Stephanie Anne Holland Jones

    2014-10-01

    Full Text Available One way to explore how prior sensory and motor events impact eye movements is to ask someone to look to targets located about a central point, returning gaze to the central point after each eye movement. Concerned about the contribution of this return to centre movement, Anderson et al. (2008 used a sequential saccade paradigm in which participants made a continuous series of saccades to peripheral targets that appeared to the left or right of the currently fixated location in a random sequence (the next eye movement began from the last target location. Examining the effects of previous saccades (n-x on current saccade latency (n, they found that saccadic reaction times (RT were reduced when the direction of the current saccade matched that of a preceding saccade (e.g. two left saccades, even when the two saccades in question were separated by multiple saccades in any direction. We examined if this pattern extends to conditions in which targets appear inside continuously marked locations that provide stable visual features (i.e. target ‘placeholders’ and when saccades are prompted by central arrows. Participants completed 3 conditions: peripheral targets (PT; continuous, sequential saccades to peripherally presented targets without placeholders; PT with placeholders; and centrally presented arrows (CA; left or right pointing arrows at the currently fixated location instructing participants to saccade to the left or right. We found reduced saccadic RT when the immediately preceding saccade (n-1 was in the same (vs. opposite direction in the PT without placeholders and CA conditions. This effect varied when considering the effect of the previous 2-5 (n-x saccades on current saccade latency (n. The effects of previous eye movements on current saccade latency may be determined by multiple, time-varying mechanisms related to sensory (i.e., retinotopic location, motor (i.e., saccade direction, and environmental (i.e., persistent visual objects

  20. Fractional Gaussian noise: Prior specification and model comparison

    KAUST Repository

    Sørbye, Sigrunn Holbek

    2017-07-07

    Fractional Gaussian noise (fGn) is a stationary stochastic process used to model antipersistent or persistent dependency structures in observed time series. Properties of the autocovariance function of fGn are characterised by the Hurst exponent (H), which, in Bayesian contexts, typically has been assigned a uniform prior on the unit interval. This paper argues why a uniform prior is unreasonable and introduces the use of a penalised complexity (PC) prior for H. The PC prior is computed to penalise divergence from the special case of white noise and is invariant to reparameterisations. An immediate advantage is that the exact same prior can be used for the autocorrelation coefficient ϕ(symbol) of a first-order autoregressive process AR(1), as this model also reflects a flexible version of white noise. Within the general setting of latent Gaussian models, this allows us to compare an fGn model component with AR(1) using Bayes factors, avoiding the confounding effects of prior choices for the two hyperparameters H and ϕ(symbol). Among others, this is useful in climate regression models where inference for underlying linear or smooth trends depends heavily on the assumed noise model.

  1. 'Pharyngocise': Randomized Controlled Trial of Preventative Exercises to Maintain Muscle Structure and Swallowing Function During Head-and-Neck Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Carnaby-Mann, Giselle, E-mail: gmann@phhp.ufl.edu [Department of Behavioral Science and Community Health, University of Florida, Gainesville, FL (United States); Crary, Michael A. [Department of Speech Language and Hearing Sciences, University of Florida, Gainesville, FL (United States); Schmalfuss, Ilona [Department of Radiology, North Florida/South Georgia Veterans Health System, Gainesville, FL (Georgia); Amdur, Robert [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States)

    2012-05-01

    Purpose: Dysphagia after chemoradiotherapy is common. The present randomized clinical trial studied the effectiveness of preventative behavioral intervention for dysphagia compared with the 'usual care.' Methods and Materials: A total of 58 head-and-neck cancer patients treated with chemoradiotherapy were randomly assigned to usual care, sham swallowing intervention, or active swallowing exercises (pharyngocise). The intervention arms were treated daily during chemoradiotherapy. The primary outcome measure was muscle size and composition (determined by T{sub 2}-weighted magnetic resonance imaging). The secondary outcomes included functional swallowing ability, dietary intake, chemosensory function, salivation, nutritional status, and the occurrence of dysphagia-related complications. Results: The swallowing musculature (genioglossus, hyoglossuss, and mylohyoid) demonstrated less structural deterioration in the active treatment arm. The functional swallowing, mouth opening, chemosensory acuity, and salivation rate deteriorated less in the pharyngocise group. Conclusion: Patients completing a program of swallowing exercises during cancer treatment demonstrated superior muscle maintenance and functional swallowing ability.

  2. Penalised Complexity Priors for Stationary Autoregressive Processes

    KAUST Repository

    Sørbye, Sigrunn Holbek

    2017-05-25

    The autoregressive (AR) process of order p(AR(p)) is a central model in time series analysis. A Bayesian approach requires the user to define a prior distribution for the coefficients of the AR(p) model. Although it is easy to write down some prior, it is not at all obvious how to understand and interpret the prior distribution, to ensure that it behaves according to the users\\' prior knowledge. In this article, we approach this problem using the recently developed ideas of penalised complexity (PC) priors. These prior have important properties like robustness and invariance to reparameterisations, as well as a clear interpretation. A PC prior is computed based on specific principles, where model component complexity is penalised in terms of deviation from simple base model formulations. In the AR(1) case, we discuss two natural base model choices, corresponding to either independence in time or no change in time. The latter case is illustrated in a survival model with possible time-dependent frailty. For higher-order processes, we propose a sequential approach, where the base model for AR(p) is the corresponding AR(p-1) model expressed using the partial autocorrelations. The properties of the new prior distribution are compared with the reference prior in a simulation study.

  3. Force limited random vibration testing: the computation of the semi-empirical constant $C(2) $ C 2 for a real test article and unknown supporting structure

    Science.gov (United States)

    Wijker, J. J.; Ellenbroek, M. H. M.; Boer, A. de

    2015-09-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load), C^2 is a very important parameter for FLVT. A number of computational methods to estimate C^2 are described in the literature, i.e. the simple and the complex two degree of freedom system, STDFS and CTDFS, respectively. The motivation of this work is to evaluate the method for the computation of a realistic value of C^2 to perform a representative random vibration test based on force limitation, when the description of the supporting structure (source) is more or less unknown. Marchand discussed the formal description of obtaining C^2, using the maximum PSD of the acceleration and maximum PSD of the force, both at the interface between test article and supporting structure. Stevens presented the coupled systems modal approach (CSMA), where simplified asparagus patch models (parallel-oscillator representation) of load and source are connected. The asparagus patch model consists of modal effective masses and spring stiffnesses associated with the natural frequencies. When the random acceleration vibration specification is given the CSMA method is suitable to compute the value of the parameter C^2. When no mathematical model of the source can be made available, estimations of the value C^2 can be find in literature. In this paper a probabilistic mathematical representation of the unknown source is proposed, such that the asparagus patch model of the source can be approximated. The chosen probabilistic design parameters have a uniform distribution. The computation of the value C^2 can be done in conjunction with the CSMA method, knowing the apparent mass of the load and the random acceleration specification at the interface between load and source, respectively. Data of two

  4. Objective structured assessment of technical skills evaluation of theoretical compared with hands-on training of shoulder dystocia management: a randomized controlled trial.

    Science.gov (United States)

    Buerkle, Bernd; Pueth, Julia; Hefler, Lukas A; Tempfer-Bentz, Eva-Katrin; Tempfer, Clemens B

    2012-10-01

    To compare the skills of performing a shoulder dystocia management algorithm after hands-on training compared with demonstration. We randomized medical students to a 30-minute hands-on (group 1) and a 30-minute demonstration (group 2) training session teaching a standardized shoulder dystocia management scheme on a pelvic training model. Participants were tested with a 22-item Objective Structured Assessment of Technical Skills scoring system after training and 72 hours thereafter. Objective Structured Assessment of Technical Skills scores were the primary outcome. Performance time, self-assessment, confidence, and global rating scale were the secondary outcomes. Statistics were performed using Mann-Whitney U test, χ test, and multiple linear regression analysis. Two hundred three participants were randomized. Objective Structured Assessment of Technical Skills scores were significantly higher in group 1 (n=103) compared with group 2 (n=100) (17.95±3.14 compared with 15.67±3.18, respectively; PTechnical Skills scores were still significantly higher in group 1 (n=67) compared with group 2 (n=60) (18.17±2.76 compared with 14.98±3.03, respectively; PTechnical Skills scores. Hands-on training helps to achieve a significant improvement of shoulder dystocia management on a pelvic training model. www.ClinicalTrials.gov, NCT01618565. I.

  5. Integrating prior information into microwave tomography part 2: Impact of errors in prior information on microwave tomography image quality.

    Science.gov (United States)

    Kurrant, Douglas; Fear, Elise; Baran, Anastasia; LoVetri, Joe

    2017-12-01

    The authors have developed a method to combine a patient-specific map of tissue structure and average dielectric properties with microwave tomography. The patient-specific map is acquired with radar-based techniques and serves as prior information for microwave tomography. The impact that the degree of structural detail included in this prior information has on image quality was reported in a previous investigation. The aim of the present study is to extend this previous work by identifying and quantifying the impact that errors in the prior information have on image quality, including the reconstruction of internal structures and lesions embedded in fibroglandular tissue. This study also extends the work of others reported in literature by emulating a clinical setting with a set of experiments that incorporate heterogeneity into both the breast interior and glandular region, as well as prior information related to both fat and glandular structures. Patient-specific structural information is acquired using radar-based methods that form a regional map of the breast. Errors are introduced to create a discrepancy in the geometry and electrical properties between the regional map and the model used to generate the data. This permits the impact that errors in the prior information have on image quality to be evaluated. Image quality is quantitatively assessed by measuring the ability of the algorithm to reconstruct both internal structures and lesions embedded in fibroglandular tissue. The study is conducted using both 2D and 3D numerical breast models constructed from MRI scans. The reconstruction results demonstrate robustness of the method relative to errors in the dielectric properties of the background regional map, and to misalignment errors. These errors do not significantly influence the reconstruction accuracy of the underlying structures, or the ability of the algorithm to reconstruct malignant tissue. Although misalignment errors do not significantly impact

  6. Structured pharmacist-led intervention programme to improve medication adherence in COPD patients: A randomized controlled study.

    Science.gov (United States)

    Abdulsalim, Suhaj; Unnikrishnan, Mazhuvancherry Kesavan; Manu, Mohan K; Alrasheedy, Alian A; Godman, Brian; Morisky, Donald E

    2017-10-26

    COPD is characterised by a progressive airflow limitation in the lungs. However, adherence to therapy improves management of symptoms and delays disease progression. Therefore, patients' knowledge and awareness about the disease are important. Hence, pharmacist-led educational interventions could achieve this and improve medication adherence. This study evaluated the effectiveness of a clinical pharmacist-led intervention on medication adherence in COPD patients in a teaching hospital. In an open-labelled randomized controlled study at Kasturba Medical College Hospital, Manipal, India, patients were randomly assigned to two groups (Intervention group [IG] and Control group [CG]), and were matched for socio-demographics and clinical characteristics. Medication adherence was assessed by the Morisky, Green and Levine Medication Adherence Questionnaire (MAQ). In IG, pharmacist intervention placed emphasis on (1) compliance, (2) smoking cessation, (3) exercise, (4) inhaler use and (5) need for timely follow up. The MAQ assessment was repeated at 6, 12, 18 and 24 months. Data were analysed statistically by SPSS version 20.0. Out of 328 patients screened during March 2012 to June 2013, 260 were recruited. Of these, 206 completed the follow-up (98 in CG and 104 in IG). Medication adherence improved significantly after pharmacist intervention in IG at all follow-up time points (P adherence in COPD patients, but was effectively reduced by the intervention. This is the first randomized controlled trial in India that demonstrates the pivotal role of pharmacist-led educational intervention in improving medication adherence in COPD. Involving non-physician health professionals could be the best strategy, for resource-poor nations like India, because the current physician-centric healthcare has no emphasis on patient education and counselling. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. A Randomized Controlled Trial to Assess Pain and Magnetic Resonance Imaging-Based (MRI-Based) Structural Spine Changes in Low Back Pain Patients After Yoga Practice

    OpenAIRE

    Telles, Shirley; Bhardwaj, Abhishek K.; Gupta, Ram K.; Sharma, Sachin K.; Monro, Robin; Balkrishna, Acharya

    2016-01-01

    Background The present study aimed at determining whether 12 weeks of yoga practice in patients with chronic LBP and MRI-based degenerative changes would result in differences in: (i) self-reported pain, anxiety, and spinal flexibility; and (ii) the structure of the discs or vertebrae. Material/Methods Sixty-two persons with MRI-proven degenerative intervertebral discs (group mean ?S.D., 36.2?6.4 years; 30 females) were randomly assigned to yoga and control groups. However, testing was conduc...

  8. Assessment of Prior Learning: An Interdisciplinary Perspective.

    Science.gov (United States)

    Preston, Kathleen

    The Assessment of Prior Learning Program at Humboldt State University, California, is described. The program enables students to gain at least token recognition, through elective units, for prior learning by taking a course and writing a portfolio that is assessed by faculty and awarded up to 10 additional units. The program began by offering…

  9. Relationship between Prior Knowledge and Reading Comprehension

    Science.gov (United States)

    Abdelaal, Noureldin Mohamed; Sase, Amal Saleh

    2014-01-01

    This study investigates the relationship between prior knowledge and reading comprehension in second language among postgraduate students in UPM. Participants in the study were 20 students who have the same level in English as a second language from several faculties. On the basis of a prior-knowledge questionnaire and test, students were…

  10. Snoezelen, structured reminiscence therapy and 10-minutes activation in long term care residents with dementia (WISDE): study protocol of a cluster randomized controlled trial.

    Science.gov (United States)

    Berg, Almuth; Sadowski, Katharina; Beyrodt, Melanie; Hanns, Stephanie; Zimmermann, Markus; Langer, Gero; Becker, Christiane; Lautenschläger, Christine; Behrens, Johann

    2010-01-31

    People with dementia are often inapproachable due to symptoms of their illness. Therefore nurses should establish relationships with dementia patients via their remaining resources and facilitate communication. In order to achieve this, different targeted non-pharmacological interventions are recommended and practiced. However there is no sufficient evidence about the efficacy of most of these interventions. A number of publications highlight the urgent need for methodological sound studies so that more robust conclusions may be drawn. The trial is designed as a cluster randomized controlled trial with 20 nursing homes in Saxony and Saxony-Anhalt (Germany) as the units of randomization. Nursing homes will be randomly allocated into 4 study groups consisting of 5 clusters and 90 residents: snoezelen, structured reminiscence therapy, 10-minutes activation or unstructured verbal communication (control group). The purpose is to determine whether the interventions are effective to reduce apathy in long-term care residents with dementia (N = 360) as the main outcome measure. Assessments will be done at baseline, 3, 6 and 12 months after beginning of the interventions. This trial will particularly contribute to the evidence on efficacy of non-pharmacological interventions in dementia care. ClinicalTrials.gov NCT00653731.

  11. Snoezelen, structured reminiscence therapy and 10-minutes activation in long term care residents with dementia (WISDE: study protocol of a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Becker Christiane

    2010-01-01

    Full Text Available Abstract Background People with dementia are often inapproachable due to symptoms of their illness. Therefore nurses should establish relationships with dementia patients via their remaining resources and facilitate communication. In order to achieve this, different targeted non-pharmacological interventions are recommended and practiced. However there is no sufficient evidence about the efficacy of most of these interventions. A number of publications highlight the urgent need for methodological sound studies so that more robust conclusions may be drawn. Methods/Design The trial is designed as a cluster randomized controlled trial with 20 nursing homes in Saxony and Saxony-Anhalt (Germany as the units of randomization. Nursing homes will be randomly allocated into 4 study groups consisting of 5 clusters and 90 residents: snoezelen, structured reminiscence therapy, 10-minutes activation or unstructured verbal communication (control group. The purpose is to determine whether the interventions are effective to reduce apathy in long-term care residents with dementia (N = 360 as the main outcome measure. Assessments will be done at baseline, 3, 6 and 12 months after beginning of the interventions. Discussion This trial will particularly contribute to the evidence on efficacy of non-pharmacological interventions in dementia care. Trial Registration ClinicalTrials.gov NCT00653731

  12. Randomization tests

    CERN Document Server

    Edgington, Eugene

    2007-01-01

    Statistical Tests That Do Not Require Random Sampling Randomization Tests Numerical Examples Randomization Tests and Nonrandom Samples The Prevalence of Nonrandom Samples in Experiments The Irrelevance of Random Samples for the Typical Experiment Generalizing from Nonrandom Samples Intelligibility Respect for the Validity of Randomization Tests Versatility Practicality Precursors of Randomization Tests Other Applications of Permutation Tests Questions and Exercises Notes References Randomized Experiments Unique Benefits of Experiments Experimentation without Mani

  13. A mathematical analysis of the effects of Hebbian learning rules on the dynamics and structure of discrete-time random recurrent neural networks.

    Science.gov (United States)

    Siri, Benoît; Berry, Hugues; Cessac, Bruno; Delord, Bruno; Quoy, Mathias

    2008-12-01

    We present a mathematical analysis of the effects of Hebbian learning in random recurrent neural networks, with a generic Hebbian learning rule, including passive forgetting and different timescales, for neuronal activity and learning dynamics. Previous numerical work has reported that Hebbian learning drives the system from chaos to a steady state through a sequence of bifurcations. Here, we interpret these results mathematically and show that these effects, involving a complex coupling between neuronal dynamics and synaptic graph structure, can be analyzed using Jacobian matrices, which introduce both a structural and a dynamical point of view on neural network evolution. Furthermore, we show that sensitivity to a learned pattern is maximal when the largest Lyapunov exponent is close to 0. We discuss how neural networks may take advantage of this regime of high functional interest.

  14. Creative music therapy to promote brain structure, function, and neurobehavioral outcomes in preterm infants: a randomized controlled pilot trial protocol.

    Science.gov (United States)

    Haslbeck, Friederike Barbara; Bucher, Hans-Ulrich; Bassler, Dirk; Hagmann, Cornelia

    2017-01-01

    Preterm birth is associated with increased risk of neurological impairment and deficits in cognition, motor function, and behavioral problems. Limited studies indicate that multi-sensory experiences support brain development in preterm infants. Music appears to promote neurobiological processes and neuronal learning in the human brain. Creative music therapy (CMT) is an individualized, interactive therapeutic approach based on the theory and methods of Nordoff and Robbins. CMT may promote brain development in preterm infants via concurrent interaction and meaningful auditory stimulation. We hypothesize that preterm infants who receive creative music therapy during neonatal intensive care admission will have developmental benefits short- and long-term brain function. A prospective, randomized controlled single-center pilot trial involving 60 clinically stable preterm infants under 32 weeks of gestational age is conducted in preparation for a multi-center trial. Thirty infants each are randomized to either standard neonatal intensive care or standard care with CMT. Music therapy intervention is approximately 20 min in duration three times per week. A trained music therapist sings for the infants in lullaby style, individually entrained and adjusted to the infant's rhythm and affect. Primary objectives of this study are feasibility of protocol implementation and investigating the potential mechanism of efficacy for this new intervention. To examine the effect of this new intervention, non-invasive, quantitative magnetic resonance imaging (MRI) methods at corrected age and standardized neurodevelopmental assessments using the Bayley Scales of Infant and Toddler Development third edition at a corrected age of 24 months and Kaufman Assessment Battery for Children at 5 years will be performed. All assessments will be performed and analyzed by blinded experts. To our knowledge, this is the first randomized controlled clinical trial to systematically examine possible

  15. Manual therapy in joint and nerve structures combined with exercises in the treatment of recurrent ankle sprains: A randomized, controlled trial.

    Science.gov (United States)

    Plaza-Manzano, Gustavo; Vergara-Vila, Marta; Val-Otero, Sandra; Rivera-Prieto, Cristina; Pecos-Martin, Daniel; Gallego-Izquierdo, Tomás; Ferragut-Garcías, Alejandro; Romero-Franco, Natalia

    2016-12-01

    Recurrent ankle sprains often involve residual symptoms for which subjects often perform proprioceptive or/and strengthening exercises. However, the effectiveness of mobilization to influence important nerve structures due to its anatomical distribution like tibial and peroneal nerves is unclear. To analyze the effects of proprioceptive/strengthening exercises versus the same exercises and manual therapy including mobilizations to influence joint and nerve structures in the management of recurrent ankle sprains. A randomized single-blind controlled clinical trial. Fifty-six patients with recurrent ankle sprains and regular sports practice were randomly assigned to experimental or control group. The control group performed 4 weeks of proprioceptive/strengthening exercises; the experimental group performed 4 weeks of the same exercises combined with manual therapy (mobilizations to influence joint and nerve structures). Pain, self-reported functional ankle instability, pressure pain threshold (PPT), ankle muscle strength, and active range of motion (ROM) were evaluated in the ankle joint before, just after and one month after the interventions. The within-group differences revealed improvements in all of the variables in both groups throughout the time. Between-group differences revealed that the experimental group exhibited lower pain levels and self-reported functional ankle instability and higher PPT, ankle muscle strength and ROM values compared to the control group immediately after the interventions and one month later. A protocol involving proprioceptive and strengthening exercises and manual therapy (mobilizations to influence joint and nerve structures) resulted in greater improvements in pain, self-reported functional joint stability, strength and ROM compared to exercises alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Structural changes and conductance thresholds in metal-free intrinsic SiO{sub x} resistive random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Mehonic, Adnan, E-mail: a.mehonic@ee.ucl.ac.uk, E-mail: t.kenyon@ucl.ac.uk; Buckwell, Mark; Montesi, Luca; Garnett, Leon; Hudziak, Stephen; Kenyon, Anthony J., E-mail: a.mehonic@ee.ucl.ac.uk, E-mail: t.kenyon@ucl.ac.uk [Department of Electronic and Electrical Engineering, UCL, Torrington Place, London WC1E 7JE (United Kingdom); Fearn, Sarah; Chater, Richard; McPhail, David [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2015-03-28

    We present an investigation of structural changes in silicon-rich silicon oxide metal-insulator-metal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G{sub 0}, is a natural boundary between the high and low resistance states of our devices.

  17. Comparison of structured and unstructured physical activity training on predicted VO2max and heart rate variability in adolescents - a randomized control trial.

    Science.gov (United States)

    Sharma, Vivek Kumar; Subramanian, Senthil Kumar; Radhakrishnan, Krishnakumar; Rajendran, Rajathi; Ravindran, Balasubramanian Sulur; Arunachalam, Vinayathan

    2017-05-01

    Physical inactivity contributes to many health issues. The WHO-recommended physical activity for adolescents encompasses aerobic, resistance, and bone strengthening exercises aimed at achieving health-related physical fitness. Heart rate variability (HRV) and maximal aerobic capacity (VO2max) are considered as noninvasive measures of cardiovascular health. The objective of this study is to compare the effect of structured and unstructured physical training on maximal aerobic capacity and HRV among adolescents. We designed a single blinded, parallel, randomized active-controlled trial (Registration No. CTRI/2013/08/003897) to compare the physiological effects of 6 months of globally recommended structured physical activity (SPA), with that of unstructured physical activity (USPA) in healthy school-going adolescents. We recruited 439 healthy student volunteers (boys: 250, girls: 189) in the age group of 12-17 years. Randomization across the groups was done using age and gender stratified randomization method, and the participants were divided into two groups: SPA (n=219, boys: 117, girls: 102) and USPA (n=220, boys: 119, girls: 101). Depending on their training status and gender the participants in both SPA and USPA groups were further subdivided into the following four sub-groups: SPA athlete boys (n=22) and girls (n=17), SPA nonathlete boys (n=95) and girls (n=85), USPA athlete boys (n=23) and girls (n=17), and USPA nonathlete boys (n=96) and girls (n=84). We recorded HRV, body fat%, and VO2 max using Rockport Walk Fitness test before and after the intervention. Maximum aerobic capacity and heart rate variability increased significantly while heart rate, systolic blood pressure, diastolic blood pressure, and body fat percentage decreased significantly after both SPA and USPA intervention. However, the improvement was more in SPA as compared to USPA. SPA is more beneficial for improving cardiorespiratory fitness, HRV, and reducing body fat percentage in terms of

  18. Terminology for pregnancy loss prior to viability

    DEFF Research Database (Denmark)

    Kolte, A M; Bernardi, L A; Christiansen, O B

    2015-01-01

    Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from...... different centres. In our opinion, terminology and definitions should be based on clinical findings, and when possible, transvaginal ultrasound. With this Early Pregnancy Consensus Statement, it is our goal to provide clear and consistent terminology for pregnancy loss prior to viability....

  19. Prior Interpersonal Violence Exposure and Experiences During and After a Disaster as Predictors of Posttraumatic Stress Disorder and Depression Among Adolescent Victims of the Spring 2011 Tornadoes.

    Science.gov (United States)

    Resnick, Heidi; Zuromski, Kelly L; Galea, Sandro; Price, Matthew; Gilmore, Amanda K; Kilpatrick, Dean G; Ruggiero, Kenneth

    2017-07-01

    The purpose of the current report was to examine prior history of exposure to interpersonal violence (IPV), as compared with prior accident or prior disaster exposure, experiences during and after a disaster, and demographic variables as predictors of past month posttraumatic stress disorder (PTSD) and depression severity among adolescents exposed to the tornadoes in Alabama and Missouri. IPV exposure has been consistently identified as a unique category of potentially traumatic events (PTE) that significantly increases risk for development of PTSD and other difficulties relative to other event types among adolescents. A population-based sample of adolescents and caregivers ( N = 2,000) were recruited randomly from tornado-affected communities in Alabama and Joplin, Missouri. Participants completed structured telephone interviews on an average of 8.8 months posttornado. Prior history of IPV was prevalent (36.5%), as was reported history of accidents (25.9%) and prior disaster exposure (26.9%). Negative binomial regression analyses with PTSD and depression symptom counts for past month as outcome variables indicated that history of predisaster IPV was most robustly related to PTSD and depression symptoms, such that those with a history of IPV endorsed over 3 times the number of symptoms than those without IPV history. Final model statistics indicated that female gender, physical injury to caregiver, concern about others' safety, prior disaster, prior accident, and prior IPV exposure were also related to PTSD. Predictors of depression symptoms were similar with the exception that concern about others' safety was not a predictor and age was a predictor in the final model. It is important to evaluate potential additive effects of IPV history in addition to recent disaster exposure variables and to consider such history when developing interventions aimed to reduce or prevent symptoms of PTSD and depression among adolescents recently exposed to disaster.

  20. An alternative time for telling: when conceptual instruction prior to problem solving improves mathematical knowledge.

    Science.gov (United States)

    Fyfe, Emily R; DeCaro, Marci S; Rittle-Johnson, Bethany

    2014-09-01

    The sequencing of learning materials greatly influences the knowledge that learners construct. Recently, learning theorists have focused on the sequencing of instruction in relation to solving related problems. The general consensus suggests explicit instruction should be provided; however, when to provide instruction remains unclear. We tested the impact of conceptual instruction preceding or following mathematics problem solving to determine when conceptual instruction should or should not be delayed. We also examined the learning processes supported to inform theories of learning more broadly. We worked with 122 second- and third-grade children. In a randomized experiment, children received instruction on the concept of math equivalence either before or after being asked to solve and explain challenging equivalence problems with feedback. Providing conceptual instruction first resulted in greater procedural knowledge and conceptual knowledge of equation structures than delaying instruction until after problem solving. Prior conceptual instruction enhanced problem solving by increasing the quality of explanations and attempted procedures. Providing conceptual instruction prior to problem solving was the more effective sequencing of activities than the reverse. We compare these results with previous, contrasting findings to outline a potential framework for understanding when instruction should or should not be delayed. © 2014 The British Psychological Society.

  1. Prior trauma and psychiatric history as risk factors for intentional and unintentional injury in Australia.

    Science.gov (United States)

    O'Donnell, Meaghan L; Creamer, Mark; Elliott, Peter; Bryant, Richard; McFarlane, Alexander; Silove, Derrick

    2009-02-01

    Preliminary evidence suggests that injury survivors are at increased risk for having experienced traumatic events before their injury or having a lifetime psychiatric history. We aimed to extend the previous research by examining in the same sample whether trauma history or lifetime psychiatric history represented risk pathways to injury for intentional or unintentional injury survivors. We also aimed to describe the co-occurrence between trauma history and psychiatric history in unintentionally injured survivors. In this multisited study, randomly selected injury survivors admitted to five trauma services in three states of Australia (April 2004 to February 2006) completed two structured clinical interviews that assessed their history of traumatic life events and lifetime psychiatric disorder (n = 1,167). chi analyses were conducted to compare the lifetime prevalence of traumatic events and psychiatric history for intentional and unintentional injury with population norms. Both intentional and unintentional injury survivors were at increased risk for reporting all types of trauma and reporting all measured psychiatric diagnoses compared with population norms. The majority of unintentional injury survivors with a psychiatric history were likely to have a trauma history. In this study, we identified that prior trauma or prior psychiatric illness may represent risk for injury in both intentionally and unintentionally injured survivors. The results highlight the need for injury-care services to address mental health issues in injury patients as part of routine care.

  2. Treating acute stress disorder and posttraumatic stress disorder with cognitive behavioral therapy or structured writing therapy: A randomized controlled trial

    NARCIS (Netherlands)

    van Emmerik, A.A.P.; Kamphuis, J.H.; Emmelkamp, P.M.G.

    2008-01-01

    Background: Writing assignments have shown promising results in treating traumatic symptomatology. Yet no studies have compared their efficacy to the current treatment of choice, cognitive behavior therapy (CBT). The present study evaluated the efficacy of structured writing therapy (SWT) and CBT as

  3. Changes in Self-Schema Structure in Cognitive Therapy for Major Depressive Disorder: A Randomized Clinical Trial

    Science.gov (United States)

    Dozois, David J. A.; Bieling, Peter J.; Patelis-Siotis, Irene; Hoar, Lori; Chudzik, Susan; McCabe, Katie; Westra, Henny A.

    2009-01-01

    Negative cognitive structure (particularly for interpersonal content) has been shown in some research to persist past a current episode of depression and potentially to be a stable marker of vulnerability for depression (D. J. A. Dozois, 2007; D. J. A. Dozois & K. S. Dobson, 2001a). Given that cognitive therapy (CT) is highly effective for…

  4. Prior Authorization of PMDs Demonstration - Status Update

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS implemented a Prior Authorization process for scooters and power wheelchairs for people with Fee-For-Service Medicare who reside in seven states with high...

  5. Attentional and Contextual Priors in Sound Perception.

    Directory of Open Access Journals (Sweden)

    Michael Wolmetz

    Full Text Available Behavioral and neural studies of selective attention have consistently demonstrated that explicit attentional cues to particular perceptual features profoundly alter perception and performance. The statistics of the sensory environment can also provide cues about what perceptual features to expect, but the extent to which these more implicit contextual cues impact perception and performance, as well as their relationship to explicit attentional cues, is not well understood. In this study, the explicit cues, or attentional prior probabilities, and the implicit cues, or contextual prior probabilities, associated with different acoustic frequencies in a detection task were simultaneously manipulated. Both attentional and contextual priors had similarly large but independent impacts on sound detectability, with evidence that listeners tracked and used contextual priors for a variety of sound classes (pure tones, harmonic complexes, and vowels. Further analyses showed that listeners updated their contextual priors rapidly and optimally, given the changing acoustic frequency statistics inherent in the paradigm. A Bayesian Observer model accounted for both attentional and contextual adaptations found with listeners. These results bolster the interpretation of perception as Bayesian inference, and suggest that some effects attributed to selective attention may be a special case of contextual prior integration along a feature axis.

  6. Inference with the Median of a Prior

    Directory of Open Access Journals (Sweden)

    Ali Mohammad-Djafari

    2006-06-01

    Full Text Available We consider the problem of inference on one of the two parameters of a probability distribution when we have some prior information on a nuisance parameter. When a prior probability distribution on this nuisance parameter is given, the marginal distribution is the classical tool to account for it. If the prior distribution is not given, but we have partial knowledge such as a fixed number of moments, we can use the maximum entropy principle to assign a prior law and thus go back to the previous case. In this work, we consider the case where we only know the median of the prior and propose a new tool for this case. This new inference tool looks like a marginal distribution. It is obtained by first remarking that the marginal distribution can be considered as the mean value of the original distribution with respect to the prior probability law of the nuisance parameter, and then, by using the median in place of the mean.

  7. Discovery of GPX4 inhibitory peptides from random peptide T7 phage display and subsequent structural analysis.

    Science.gov (United States)

    Sakamoto, Kotaro; Sogabe, Satoshi; Kamada, Yusuke; Matsumoto, Shin-Ichi; Kadotani, Akito; Sakamoto, Jun-Ichi; Tani, Akiyoshi

    2017-01-08

    The phospholipid hydroperoxidase glutathione peroxidase (GPX4) is an enzyme that reduces lipid hydroperoxides in lipid membranes. Recently, GPX4 has been investigated as a target molecule that induces iron-dependent cell death (ferroptosis) selectively in cancer cells that express mutant Ras. GPX4 inhibitors have the potential to become novel anti-cancer drugs. However, there are no druggable pockets for conventional small molecules on the molecular surface of GPX4. To generate GPX4 inhibitors, we examined the use of peptides as an alternative to small molecules. By screening peptide libraries displayed on T7 phages, and analyzing the X-ray crystal structures of the peptides, we successfully identified one peptide that binds to near Sec73 of catalytic site and two peptides that bind to another site on GPX4. To our knowledge, this is the first study reporting GPX4 inhibitory peptides and their structural information. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Stochastic Simulation of Chloride Ingress into Reinforced Concrete Structures by Means of Multi-Dimensional Gaussian Random Fields

    DEFF Research Database (Denmark)

    Frier, Christian; Sørensen, John Dalsgaard

    2005-01-01

    For many reinforced concrete structures corrosion of the reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation occurs when the chloride content....... As an example a bridge pier in a marine environment is considered and the results are given in terms of the distribution of the time for initialization of corrosion...

  9. Independent and combined effects of calcium-vitamin D3 and exercise on bone structure and strength in older men: an 18-month factorial design randomized controlled trial.

    Science.gov (United States)

    Kukuljan, Sonja; Nowson, Caryl A; Sanders, Kerrie M; Nicholson, Geoff C; Seibel, Markus J; Salmon, Jo; Daly, Robin M

    2011-04-01

    Exercise and calcium-vitamin D are independently recognized as important strategies to prevent osteoporosis, but their combined effects on bone strength and its determinants remain uncertain. To assess whether calcium-vitamin D(3) fortified milk could enhance the effects of exercise on bone strength, structure, and mineral density in middle-aged and older men. An 18-month factorial design randomized controlled trial in which 180 men aged 50-79 years were randomized to the following: exercise + fortified milk; exercise; fortified milk; or controls. Exercise consisted of progressive resistance training with weight-bearing impact activities performed 3 d/week. Men assigned to fortified milk consumed 400 ml/d of 1% fat milk containing 1000 mg/d calcium and 800 IU/d vitamin D(3). Changes in bone mineral density (BMD), bone structure, and strength at the lumbar spine (LS), proximal femur, mid-femur, and mid-tibia measured by dual energy x-ray absorptiometry and/or quantitative computed tomography. There were no exercise-by-fortified milk interactions at any skeletal site. Main effect analysis showed that exercise led to a 2.1% (95% confidence interval, 0.5-3.6) net gain in femoral neck section modulus, which was associated with an approximately 1.9% gain in areal BMD and cross-sectional area. Exercise also improved LS trabecular BMD [net gain 2.2% (95% confidence interval, 0.2-4.1)], but had no effect on mid-femur or mid-tibia BMD, structure, or strength. There were no main effects of the fortified milk at any skeletal site. A community-based multi-component exercise program successfully improved LS and femoral neck BMD and strength in healthy older men, but providing additional calcium-vitamin D(3) to these replete men did not enhance the osteogenic response.

  10. Weakly supervised semantic segmentation using fore-background priors

    Science.gov (United States)

    Han, Zheng; Xiao, Zhitao; Yu, Mingjun

    2017-07-01

    Weakly-supervised semantic segmentation is a challenge in the field of computer vision. Most previous works utilize the labels of the whole training set and thereby need the construction of a relationship graph about image labels, thus result in expensive computation. In this study, we tackle this problem from a different perspective. We proposed a novel semantic segmentation algorithm based on background priors, which avoids the construction of a huge graph in whole training dataset. Specifically, a random forest classifier is obtained using weakly supervised training data .Then semantic texton forest (STF) feature is extracted from image superpixels. Finally, a CRF based optimization algorithm is proposed. The unary potential of CRF derived from the outputting probability of random forest classifier and the robust saliency map as background prior. Experiments on the MSRC21 dataset show that the new algorithm outperforms some previous influential weakly-supervised segmentation algorithms. Furthermore, the use of efficient decision forests classifier and parallel computing of saliency map significantly accelerates the implementation.

  11. A randomized controlled clinical trial of a nurse-led structured psychosocial intervention program for people with first-onset mental illness in psychiatric outpatient clinics.

    Science.gov (United States)

    Chien, Wai-Tong; Bressington, Daniel

    2015-09-30

    This study aimed to test the effectiveness of a nurse-led structured psychosocial intervention program in Chinese patients with first-onset mental illness. A single-blind, parallel group, randomized controlled trial design was used. The study involved 180 participants with mild to moderate-severe symptoms of psychotic or mood disorders who were newly referred to two psychiatric outpatient clinics in Hong Kong. Patients were randomly assigned to either an eight-session nurse-led psychosocial intervention program (plus usual care) or usual psychiatric outpatient care (both n=90). The primary outcome was psychiatric symptoms. Outcomes were measured at recruitment, one week and 12 months post-intervention. Patients in the psychosocial intervention group reported statistically significant improvements in symptoms compared to treatment as usual. There were also significant improvements in illness insight and perceived quality of life and reduction in length of re-hospitalizations over the 12-month follow-up. The findings provide evidence that the nurse-led psychosocial intervention program resulted in improved health outcomes in Chinese patients with first-onset mental illness. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. A randomized comparison of video demonstration versus hands-on training of medical students for vacuum delivery using Objective Structured Assessment of Technical Skills (OSATS).

    Science.gov (United States)

    Hilal, Ziad; Kumpernatz, Anne K; Rezniczek, Günther A; Cetin, Cem; Tempfer-Bentz, Eva-Katrin; Tempfer, Clemens B

    2017-03-01

    To compare medical students' skills for vaginal operative delivery by vacuum extraction (VE) after hands-on training versus video demonstration. We randomized medical students to an expert demonstration (group 1) or a hands-on (group 2) training using a standardized VE algorithm on a pelvic training model. Students were tested with a 40-item Objective Structured Assessment of Technical Skills (OSATS) scoring system after training and 4 days later. OSATS scores were the primary outcome. Performance time, self-assessment, confidence, and global rating scale were secondary outcomes. We assessed the constructive validity of OSATS in this VE model comparing metric scores of experts and students. In all, 137 students were randomized. OSATS scores were higher in group 2 (n = 63) compared with group 1 (n = 74) (32.89 ± 6.39 vs 27.51 ± 10.27, respectively; P video demonstration for teaching VE on a pelvic model.

  13. Dynamic emotion perception and prior expectancy.

    Science.gov (United States)

    Dzafic, Ilvana; Martin, Andrew K; Hocking, Julia; Mowry, Bryan; Burianová, Hana

    2016-06-01

    Social interactions require the ability to rapidly perceive emotion from various incoming dynamic, multisensory cues. Prior expectations reduce incoming emotional information and direct attention to cues that are aligned with what is expected. Studies to date have investigated the prior expectancy effect using static emotional images, despite the fact that dynamic stimuli would represent greater ecological validity. The objective of the study was to create a novel functional magnetic resonance imaging (fMRI) paradigm to examine the influence of prior expectations on naturalistic emotion perception. For this purpose, we developed a dynamic emotion perception task, which consisted of audio-visual videos that carry emotional information congruent or incongruent with prior expectations. The results show that emotional congruency was associated with activity in prefrontal regions, amygdala, and putamen, whereas emotional incongruency was associated with activity in temporoparietal junction and mid-cingulate gyrus. Supported by the behavioural results, our findings suggest that prior expectations are reinforced after repeated experience and learning, whereas unexpected emotions may rely on fast change detection processes. The results from the current study are compatible with the notion that the ability to automatically detect unexpected changes in complex dynamic environments allows for adaptive behaviours in potentially advantageous or threatening situations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. External priors for the next generation of CMB experiments

    Energy Technology Data Exchange (ETDEWEB)

    Manzotti, Alessandro; Dodelson, Scott; Park, Youngsoo

    2016-03-01

    Planned cosmic microwave background (CMB) experiments can dramatically improve what we know about neutrino physics, inflation, and dark energy. The low level of noise, together with improved angular resolution, will increase the signal to noise of the CMB polarized signal as well as the reconstructed lensing potential of high redshift large scale structure. Projected constraints on cosmological parameters are extremely tight, but these can be improved even further with information from external experiments. Here, we examine quantitatively the extent to which external priors can lead to improvement in projected constraints from a CMB-Stage IV (S4) experiment on neutrino and dark energy properties. We find that CMB S4 constraints on neutrino mass could be strongly enhanced by external constraints on the cold dark matter density $\\Omega_{c}h^{2}$ and the Hubble constant $H_{0}$. If polarization on the largest scales ($\\ell<50$) will not be measured, an external prior on the primordial amplitude $A_{s}$ or the optical depth $\\tau$ will also be important. A CMB constraint on the number of relativistic degrees of freedom, $N_{\\rm eff}$, will benefit from an external prior on the spectral index $n_{s}$ and the baryon energy density $\\Omega_{b}h^{2}$. Finally, an external prior on $H_{0}$ will help constrain the dark energy equation of state ($w$).

  15. Hysteresis as an Implicit Prior in Tactile Spatial Decision Making

    Science.gov (United States)

    Thiel, Sabrina D.; Bitzer, Sebastian; Nierhaus, Till; Kalberlah, Christian; Preusser, Sven; Neumann, Jane; Nikulin, Vadim V.; van der Meer, Elke; Villringer, Arno; Pleger, Burkhard

    2014-01-01

    Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide ‘same’ rather than ‘different’ on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants’ decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence. PMID:24587045

  16. Would older adults with mild cognitive impairment adhere to and benefit from a structured lifestyle activity intervention to enhance cognition?: a cluster randomized controlled trial.

    Science.gov (United States)

    Lam, Linda Chiu-Wa; Chan, Wai Chi; Leung, Tony; Fung, Ada Wai-Tung; Leung, Edward Man-Fuk

    2015-01-01

    Epidemiologic evidence suggests that cognitive and physical activities are associated with better cognition in late life. The present study was conducted to examine the possible benefits of four structured lifestyle activity interventions and compare their effectiveness in optimizing cognition for older adults with mild cognitive impairment (MCI). This was a 12-month cluster randomized controlled trial. 555 community-dwelling Chinese older adults with MCI (295 with multiple-domain deficits (mdMCI), 260 with single-domain deficit (sdMCI)) were recruited. Participants were randomized into physical exercise (P), cognitive activity (C), integrated cognitive and physical exercise (CP), and social activity (S, active control) groups. Interventions comprised of one-hour structured activities three times per week. Primary outcome was Clinical Dementia Rating sum of boxes (CDR-SOB) scores. Secondary outcomes included Chinese versions of Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog), delayed recall, Mini-Mental State Examination, Category Verbal Fluency Test (CVFT) and Disability Assessment for Dementia - Instrumental Activities of Daily Living (DAD-IADL). Percentage adherence to programs and factors affecting adherence were also examined. At 12th month, 423 (76.2%) completed final assessment. There was no change in CDR-SOB and DAD-IADL scores across time and intervention groups. Multilevel normal model and linear link function showed improvement in ADAS-Cog, delayed recall and CVFT with time (peveryday functioning, albeit with some improvements in cognitive scores across time. Higher adherence was associated with greater improvement in cognitive scores. Factors to enhance adherence should be specially considered in the design of psychosocial interventions for older adults with cognitive decline. ClinicalTrials.gov ChiCTR-TRC-11001359.

  17. GENERAL ASPECTS REGARDING THE PRIOR DISCIPLINARY RESEARCH

    Directory of Open Access Journals (Sweden)

    ANDRA PURAN (DASCĂLU

    2012-05-01

    Full Text Available Disciplinary research is the first phase of the disciplinary action. According to art. 251 paragraph 1 of the Labour Code no disciplinary sanction may be ordered before performing the prior disciplinary research.These regulations provide an exception: the sanction of written warning. The current regulations in question, kept from the old regulation, provides a protection for employees against abuses made by employers, since sanctions are affecting the salary or the position held, or even the development of individual employment contract. Thus, prior research of the fact that is a misconduct, before a disciplinary sanction is applied, is an essential condition for the validity of the measure ordered. Through this study we try to highlight some general issues concerning the characteristics, processes and effects of prior disciplinary research.

  18. Numbers and prior knowledge in sentence comprehension

    Directory of Open Access Journals (Sweden)

    Pedro Macizo

    2013-01-01

    Full Text Available We evaluated whether the comprehension of sentences that contained numerical information could benefit from presenting numbers in Arabic format and from using prior knowledge. Participants read sentences including numbers (Arabic digits or number words while the comprehension accuracy was evaluated. In addition, the sentences were biased or unbiased by people's prior knowledge about quantities. The results showed better comprehension for sentences that contained Arabic digits as compared to number words. Moreover, biased sentences were understood more accurately than unbiased sentences. These results indicate that information about magnitude in sentence context is comprehended better when quantities are presented in Arabic format and when they are associated with participants' world knowledge.

  19. Validity in assessment of prior learning

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    2015-01-01

    , the article discusses the need for specific criteria for assessment. The reliability and validity of the assessment procedures depend on whether the competences are well-defined, and whether the teachers are adequately trained for the assessment procedures. Keywords: assessment, prior learning, adult......The article deals with the results of a study of school-based assessment of adults who have enrolled as students at a vocational college in order to qualify for occupations as skilled workers. Based on examples of methods for assessing the students’ prior learning in a programme for hairdressers...

  20. Combining Exergame Training with Omega-3 Fatty Acid Supplementation: Protocol for a Randomized Controlled Study assessing the Effect on Neuronal Structure/Function in the Elderly Brain

    Directory of Open Access Journals (Sweden)

    Alexandra Schättin

    2016-11-01

    Full Text Available A common problem in the older population is the risk of falling that might lead to injury, immobility, and reduced survival. Age-related neuronal changes, e.g. decline in grey- and white-matter, affect neuronal, cognitive, and motor functioning. The improvement of these factors might decrease fall events in elderly. Studies showed that the sole administration of video game-based physical exercise, a so-called exergame, or omega-3 fatty acid (FA may improve motor and/or cognitive functioning through neuronal changes in the brain of older adults. The aim of this study is to assess the effects of a combination of exergame training with omega-3 FA supplementation on the elderly brain. We hypothesize that an intervention using a combination approach differently effects on the neuronal structure and function of the elderly’s brain as compared to the sole administration of exergame training. The study is a parallel, double-blinded, randomized controlled trial lasting 26 weeks. Sixty autonomous living, non-smoking, and right-handed healthy older (>65 years adults who live independently or in a senior residency are included, randomized, and allocated to one of two study groups. The experimental group receives a daily amount of 13.5ml fish oil (including 2.9g of omega-3 FA, whereas the control group receives a daily amount of 13.5ml olive oil for 26 weeks. After 16 weeks, both groups start with an exergame training program three times per week. Measurements are performed on three time-points by treatment blinded investigators: pre-intervention measurement, blood sample after 16 week, and post-intervention measurements. The main outcomes are motor evoked potentials of the right M. tibialis anterior (transcranial magnetic stimulation and response-related potentials (electroencephalography during a cognitive test. For secondary outcomes, reaction times during cognitive tests and spatio-temporal parameters during gait performance are measured. Statistics

  1. A morphological and structural approach to evaluate the electromagnetic performances of composites based on random networks of carbon nanotubes

    Science.gov (United States)

    De Vivo, B.; Lamberti, P.; Spinelli, G.; Tucci, V.

    2014-04-01

    Small quantities of carbon nanotubes (CNTs) in polymer resins allow to obtain new lightweight nanocomposites suitable for microwave applications, such as efficient electromagnetic shielding or radar absorbing materials. The availability of appropriate simulation models taking into account the morphological and physical features of such very interesting composites is very important for design and performance optimization of devices and systems. In this study, a 3-dimensional (3D) numerical structure modeling the morphology of a CNT-based composite is considered in order to carry out a computational analysis of their electromagnetic performances. The main innovative features of the proposed model consists in the identification of a resistance and capacitance network whose values depend on the filler geometry and loading and whose complexity is associated with the percolation paths. Tunneling effect and capacitive interactions between the individual conductive particles are properly taken into account. The obtained network allows an easy calculation in a wide frequency range of the complex permittivity and others electromagnetic parameters. Moreover, a reliable sensitivity analysis concerning the impact of some crucial parameters, such as the CNTs properties and the dielectric permittivity of the neat resin, on the electromagnetic features of the resulting composites can be carried out. The model predictions are in good agreement with existing experimental data, suggesting that the proposed model can be a useful tool for their design and performance optimization in the microwave range.

  2. Media arrangement impacts cell growth in anaerobic fixed-bed reactors treating sugarcane vinasse: Structured vs. randomic biomass immobilization.

    Science.gov (United States)

    de Aquino, Samuel; Fuess, Lucas Tadeu; Pires, Eduardo Cleto

    2017-07-01

    This study reports on the application of an innovative structured-bed reactor (FVR) as an alternative to conventional packed-bed reactors (PBRs) to treat high-strength solid-rich wastewaters. Using the FVR prevents solids from accumulating within the fixed-bed, while maintaining the advantages of the biomass immobilization. The long-term operation (330days) of a FVR and a PBR applied to sugarcane vinasse under increasing organic loads (2.4-18.0kgCODm -3 day -1 ) was assessed, focusing on the impacts of the different media arrangements over the production and retention of biomass. Much higher organic matter degradation rates, as well as long-term operational stability and high conversion efficiencies (>80%) confirmed that the FVR performed better than the PBR. Despite the equivalent operating conditions, the biomass growth yield was different in both reactors, i.e., 0.095gVSSg -1 COD (FVR) and 0.066gVSSg -1 COD (PBR), indicating a clear control of the media arrangement over the biomass production in fixed-bed reactors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Assessing the amount of quadruplex structures present within G₂-tract synthetic random-sequence DNA libraries.

    Directory of Open Access Journals (Sweden)

    Simon A McManus

    Full Text Available The process of in vitro selection has led to the discovery of many aptamers with potential to be developed into inhibitors and biosensors, but problems in isolating aptamers against certain targets with desired affinity and specificity still remain. One possible improvement is to use libraries enhanced for motifs repeatedly isolated in aptamer molecules. One such frequently observed motif is the two-tiered guanine quadruplex. In this study we investigated whether DNA libraries could be designed to contain a large fraction of molecules capable of folding into two-tiered guanine quadruplexes. Using comprehensive circular dichroism analysis, we found that DNA libraries could be designed to contain a large proportion of sequences that adopt guanine quadruplex structures. Analysis of individual sequences from a small library revealed a mixture of quadruplexes of different topologies providing the diversity desired for an in vitro selection. We also found that primer-binding sites are detrimental to quadruplex formation and devised a method for post-selection amplification of primer-less quadruplex libraries. With the development of guanine quadruplex enriched DNA libraries, it should be possible to improve the chances of isolating aptamers that utilize a quadruplex scaffold and enhance the success of in vitro selection experiments.

  4. Integer Ratio Priors on Musical Rhythm Revealed Cross-culturally by Iterated Reproduction.

    Science.gov (United States)

    Jacoby, Nori; McDermott, Josh H

    2017-02-06

    Probability distributions over external states (priors) are essential to the interpretation of sensory signals. Priors for cultural artifacts such as music and language remain largely uncharacterized, but likely constrain cultural transmission, because only those signals with high probability under the prior can be reliably reproduced and communicated. We developed a method to estimate priors for simple rhythms via iterated reproduction of random temporal sequences. Listeners were asked to reproduce random "seed" rhythms; their reproductions were fed back as the stimulus and over time became dominated by internal biases, such that the prior could be estimated by applying the procedure multiple times. We validated that the measured prior was consistent across the modality of reproduction and that it correctly predicted perceptual discrimination. We then measured listeners' priors over the entire space of two- and three-interval rhythms. Priors in US participants showed peaks at rhythms with simple integer ratios and were similar for musicians and non-musicians. An analogous procedure produced qualitatively different results for spoken phrases, indicating some specificity to music. Priors measured in members of a native Amazonian society were distinct from those in US participants but also featured integer ratio peaks. The results do not preclude biological constraints favoring integer ratios, but they suggest that priors on musical rhythm are substantially modulated by experience and may simply reflect the empirical distribution of rhythm that listeners encounter. The proposed method can efficiently map out a high-resolution view of biases that shape transmission and stability of simple reproducible patterns within a culture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Evaluation of the macula prior to cataract surgery.

    Science.gov (United States)

    McKeague, Marta; Sharma, Priya; Ho, Allen C

    2018-01-01

    To describe recent evidence regarding methods of evaluation of retinal structure and function prior to cataract surgery. Studies in patients with cataract but no clinically detectable retinal disease have shown that routine use of optical coherence tomography (OCT) prior to cataract surgery can detect subtle macular disease, which may alter the course of treatment or lead to modification of consent. The routine use of OCT has been especially useful in patients being considered for advanced-technology intraocular lenses (IOLs) as subtle macular disease can be a contraindication to the use of these lenses. The cost-effectiveness of routine use of OCT prior to cataract surgery has not been studied. Other technologies that assess retinal function rather than structure, such as microperimetry and electroretinogram (ERG) need further study to determine whether they can predict retinal potential in cataract patients. There is growing evidence for the importance of more detailed retinal evaluation of cataract patients even with clinically normal exam. OCT has been the most established and studied method for retinal evaluation in cataract patients, but other technologies such as microperimetry and ERG are beginning to be studied.

  6. Recognition of Prior Learning: The Participants' Perspective

    Science.gov (United States)

    Miguel, Marta C.; Ornelas, José H.; Maroco, João P.

    2016-01-01

    The current narrative on lifelong learning goes beyond formal education and training, including learning at work, in the family and in the community. Recognition of prior learning is a process of evaluation of those skills and knowledge acquired through life experience, allowing them to be formally recognized by the qualification systems. It is a…

  7. Student Models for Prior Knowledge Estimation

    Science.gov (United States)

    Nižnan, Juraj; Pelánek, Radek; Rihák, Jirí

    2015-01-01

    Intelligent behavior of adaptive educational systems is based on student models. Most research in student modeling focuses on student learning (acquisition of skills). We focus on prior knowledge, which gets much less attention in modeling and yet can be highly varied and have important consequences for the use of educational systems. We describe…

  8. Reichenbach, Prior and Hybrid Tense Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2016-01-01

    In this paper we combine central insights of Prior and Reichenbach in the framework of hybrid tense logic. We do so in a way that overcomes a well-known defect of Reichenbach’s original tense schema, namely that it gives multiple representations to sentences in the Future perfect and the Future...

  9. Prior learning assessment and quality assurance practice ...

    African Journals Online (AJOL)

    ... Prior Learning) in higher education to assess RPL candidates for admission into programmes of study met with a lot of criticism from faculty academics. Lecturers viewed the possibility of admitting large numbers of under-qualified adult learners, as a threat to the institution's reputation, or an erosion of academic standards.

  10. Respiratory risk assessment prior to extrathoracic surgery

    African Journals Online (AJOL)

    2011-04-11

    Apr 11, 2011 ... after surgery, including early hypoxemia and unplanned reintubation.10 While the literature is still emerging, OSA should be considered to be a probable risk factor for pulmonary complications after surgery. At present, it is unknown whether patients without OSA should be screened prior to elective surgery.

  11. Models for Validation of Prior Learning (VPL)

    DEFF Research Database (Denmark)

    Ehlers, Søren

    would have been categorized as utopian can become realpolitik. Validation of Prior Learning (VPL) was in Europe mainly regarded as utopian while universities in the United States of America (USA) were developing ways to obtain credits to those students which was coming with experiences from working life....

  12. Prior Learning Assessment with Latent Semantic Analysis

    NARCIS (Netherlands)

    Kalz, Marco; Van Bruggen, Jan; Giesbers, Bas; Koper, Rob

    2007-01-01

    Kalz, M., Van Bruggen, J., Giesbers, B., & Koper, R. (2007). Prior Learning Assessment with Latent Semantic Analysis. In F. Wild, M. Kalz, J. Van Bruggen & R. Koper (Eds.). Proceedings of the First European Workshop on Latent Semantic Analysis in Technology Enhanced Learning (pp. 24-25). Heerlen,

  13. Prior Learning Assessment with Latent Semantic Analysis

    OpenAIRE

    Kalz, Marco; van Bruggen, Jan; Giesbers, Bas; Koper, Rob

    2007-01-01

    Kalz, M., Van Bruggen, J., Giesbers, B., & Koper, R. (2007). Prior Learning Assessment with Latent Semantic Analysis. In F. Wild, M. Kalz, J. Van Bruggen & R. Koper (Eds.). Proceedings of the First European Workshop on Latent Semantic Analysis in Technology Enhanced Learning (pp. 24-25). Heerlen, The Netherlands: Open University of the Netherlands.

  14. Prior listening in rooms improves speech intelligibility.

    Science.gov (United States)

    Brandewie, Eugene; Zahorik, Pavel

    2010-07-01

    Although results from previous studies have demonstrated that the acoustic effects of a single reflection are perceptually suppressed after repeated exposure to a particular configuration of source and reflection, the extent to which this dynamic echo suppression might generalize to speech understanding in room environments with multiple reflections and reverberation is largely unknown. Here speech intelligibility was measured using the coordinate response measure corpus both with and without prior listening exposure to a reverberant room environment, which was simulated using virtual auditory space techniques. Prior room listening exposure was manipulated by presenting either a two-sentence carrier phrase that preceded the target speech, or no carrier phrase within the room environment. Results from 14 listeners indicate that with prior room exposure, masked speech reception thresholds were on average 2.7 dB lower than thresholds without exposure, an improvement in intelligibility of over 18 percentage points on average. This effect, which is shown to be absent in anechoic space and greatly reduced under monaural listening conditions, demonstrates that prior binaural exposure to reverberant rooms can improve speech intelligibility, perhaps due to a process of perceptual adaptation to the acoustics of the listening room.

  15. Offending prior to first psychiatric contact

    DEFF Research Database (Denmark)

    Stevens, Hanne; Agerbo, Esben; Dean, K

    2012-01-01

    There is a well-established association between psychotic disorders and subsequent offending but the extent to which those who develop psychosis might have a prior history of offending is less clear. Little is known about whether the association between illness and offending exists in non-psychot...

  16. Short Report Biochemical derangements prior to emergency ...

    African Journals Online (AJOL)

    The aim of this study was to examine biochemical investigations not routinely performed prior to emergency laparotomy in patients at Queen Elizabeth. Central Hospital, a low-resource public hospital in Blantyre, Malawi.. Methods. A prospective cross-sectional study of adults (N = 15) needing emergency laparotomy over a ...

  17. 19 CFR 162.74 - Prior disclosure.

    Science.gov (United States)

    2010-04-01

    ..., so informed the person of the type of or circumstances of the disclosed violation; or (ii) A Customs... 19 Customs Duties 2 2010-04-01 2010-04-01 false Prior disclosure. 162.74 Section 162.74 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY...

  18. Modelling heterogeneity variances in multiple treatment comparison meta-analysis ��� Are informative priors the better solution?

    Directory of Open Access Journals (Sweden)

    Thorlund Kristian

    2013-01-01

    Full Text Available Abstract Background Multiple treatment comparison (MTC meta-analyses are commonly modeled in a Bayesian framework, and weakly informative priors are typically preferred to mirror familiar data driven frequentist approaches. Random-effects MTCs have commonly modeled heterogeneity under the assumption that the between-trial variance for all involved treatment comparisons are equal (i.e., the ‘common variance’ assumption. This approach ‘borrows strength’ for heterogeneity estimation across treatment comparisons, and thus, ads valuable precision when data is sparse. The homogeneous variance assumption, however, is unrealistic and can severely bias variance estimates. Consequently 95% credible intervals may not retain nominal coverage, and treatment rank probabilities may become distorted. Relaxing the homogeneous variance assumption may be equally problematic due to reduced precision. To regain good precision, moderately informative variance priors or additional mathematical assumptions may be necessary. Methods In this paper we describe four novel approaches to modeling heterogeneity variance - two novel model structures, and two approaches for use of moderately informative variance priors. We examine the relative performance of all approaches in two illustrative MTC data sets. We particularly compare between-study heterogeneity estimates and model fits, treatment effect estimates and 95% credible intervals, and treatment rank probabilities. Results In both data sets, use of moderately informative variance priors constructed from the pair wise meta-analysis data yielded the best model fit and narrower credible intervals. Imposing consistency equations on variance estimates, assuming variances to be exchangeable, or using empirically informed variance priors also yielded good model fits and narrow credible intervals. The homogeneous variance model yielded high precision at all times, but overall inadequate estimates of between

  19. Infrared image enhancement based on novel multiscale feature prior

    Science.gov (United States)

    Fan, Zunlin; Bi, Duyan; Xiong, Lei; Ding, Wenshan; Gao, Shan; Li, Cheng

    2017-04-01

    Infrared images have shortcomings of background noise, few details, and fuzzy edges. Therefore, noise suppression and detail enhancement play crucial roles in the infrared image technology field. To effectively enhance details and eliminate noises, an infrared image processing algorithm based on multiscale feature prior is proposed. First, the maximum a posterior model estimating optimal free-noise results is constructed and discussed. Second, based on the extended 16 high-order differential operators and multiscale features, we propose a structure feature prior that is immune to noises and depicts infrared image features more precisely. Third, with the noise-suppressed image, the final image is enhanced by the improved multiscale unsharp mask algorithm, which enhances details and edges adaptively. Finally, testing infrared images in different signal-to-noise ratio scenes, the effectiveness and robustness of the proposed approach is analyzed. Compared with other well-established methods, the proposed method shows the evident performance in terms of noise suppression and edge enhancement.

  20. Myofascial structural integration therapy on gross motor function and gait of young children with spastic cerebral palsy: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Elizabeth C Loi

    2015-09-01

    Full Text Available Though the cause of motor abnormalities in cerebral palsy is injury to the brain, structural changes in muscle and fascia may add to stiffness and reduced function. This study examined whether Myofascial Structural Integration therapy (MSI, a complementary treatment that manipulates muscle and fascia, would improve gross motor function and gait in children < 4 years with cerebral palsy. Participants (N=29 were enrolled in a randomized controlled trial (RCT: NCT01815814, https://goo.gl/TGxvwd or Open Label Extension. The main outcome was the Gross Motor Function Measure-66 assessed at 3-month intervals. Gait (n=8 was assessed using the GAITRite® electronic walkway. Parents completed a survey at study conclusion.Comparing Treatment (n=15 and Waitlist-Control Groups (n=9, we found a significant main effect of time but no effect of group or timeXgroup interaction. The pooled sample (n=27 showed a main effect of time, but no significantly greater change after treatment than between other assessments. Foot length on the affected side increased significantly after treatment, likely indicating improvement in the children’s ability to approach a heel strike. Parent surveys indicated satisfaction and improvements in the children's quality of movement. MSI did not increase the rate of motor skill development, but was associated with improvement in gait quality.

  1. Crystalline structure and magnetic properties of Fe2CrSi Heusler alloy films: New ferromagnetic material for high-performance magnetic random access memory

    Science.gov (United States)

    Yoshimura, S.; Asano, H.; Nakamura, Y.; Yamaji, K.; Takeda, Y.; Matsui, M.; Ishida, S.; Nozaki, Y.; Matsuyama, K.

    2008-04-01

    A new Heusler alloy, Fe2CrSi, which has high spin polarization (P), low saturation magnetization (Ms), and a low Curie temperature (TC), was investigated in order to fabricate high-performance magnetic tunnel junctions (MTJs) with a high tunnel magnetoresistance ratio and with low critical current for the spin-transfer switching method, or a low switching field for the thermally assisted magnetization reversal technique. The main results are as follows: (1) P and the magnetic moment of Fe2CrSi with an L21 structure were 0.98 and 1.98μB/f.u., respectively, according to density of states calculations. (2) Fe2CrSi films show the (100) orientation with a B2 structure on a MgO substrate upon a thermal treatment with optimum temperature and duration. (3) Fe2CrSi films have Ms and TC values of 385emu /cm3 and 630K, respectively. (4) The (100) oriented epitaxial MTJs are produced with Fe2CrSi films fabricated with the optimized thermal treatment condition. It is found that the Fe2CrSi Heusler alloy films are a suitable ferromagnetic material for high-performance magnetic random access memory.

  2. Would older adults with mild cognitive impairment adhere to and benefit from a structured lifestyle activity intervention to enhance cognition?: a cluster randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Linda Chiu-Wa Lam

    Full Text Available Epidemiologic evidence suggests that cognitive and physical activities are associated with better cognition in late life. The present study was conducted to examine the possible benefits of four structured lifestyle activity interventions and compare their effectiveness in optimizing cognition for older adults with mild cognitive impairment (MCI.This was a 12-month cluster randomized controlled trial. 555 community-dwelling Chinese older adults with MCI (295 with multiple-domain deficits (mdMCI, 260 with single-domain deficit (sdMCI were recruited. Participants were randomized into physical exercise (P, cognitive activity (C, integrated cognitive and physical exercise (CP, and social activity (S, active control groups. Interventions comprised of one-hour structured activities three times per week. Primary outcome was Clinical Dementia Rating sum of boxes (CDR-SOB scores. Secondary outcomes included Chinese versions of Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog, delayed recall, Mini-Mental State Examination, Category Verbal Fluency Test (CVFT and Disability Assessment for Dementia - Instrumental Activities of Daily Living (DAD-IADL. Percentage adherence to programs and factors affecting adherence were also examined. At 12th month, 423 (76.2% completed final assessment. There was no change in CDR-SOB and DAD-IADL scores across time and intervention groups. Multilevel normal model and linear link function showed improvement in ADAS-Cog, delayed recall and CVFT with time (p<0.05. Post-hoc subgroup analyses showed that the CP group, compared with other intervention groups, had more significant improvements of ADAS-Cog, delayed recall and CVFT performance with sdMCI participants (p<0.05. Overall adherence rate was 73.3%. Improvements in ADAS-Cog and delayed recall scores were associated with adherence after controlling for age, education, and intervention groups (univariate analyses.Structured lifestyle activity interventions

  3. A randomized trial comparing structured and lifestyle goals in an internet-mediated walking program for people with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Fortlage Laurie A

    2007-11-01

    Full Text Available Abstract Background The majority of individuals with type 2 diabetes do not exercise regularly. Pedometer-based walking interventions can help; however, pedometer-based interventions targeting only total daily accumulated steps might not yield the same health benefits as physical activity programs specifying a minimum duration and intensity of physical activity bouts. Methods This pilot randomized trial compared two goal-setting strategies: 1 lifestyle goals targeting total daily accumulated step counts and 2 structured goals targeting bout steps defined as walking that lasts for 10 minutes or longer at a pace of at least 60 steps per minute. We sought to determine which goal-setting strategy was more effective at increasing bout steps. Participants were sedentary adults with type 2 diabetes. All participants: wore enhanced pedometers with embedded USB ports; uploaded detailed, time-stamped step-count data to a website called Stepping Up to Health; and received automated step-count feedback, automatically calculated goals, and tailored motivational messages throughout the six-week intervention. Only the automated goal calculations and step-count feedback differed between the two groups. The primary outcome of interest was increase in steps taken during the previously defined bouts of walking (lasting at least 10 minutes or longer at a pace of at least 60 steps per minute between baseline and end of the intervention. Results Thirty-five participants were randomized and 30 (86% completed the pilot study. Both groups significantly increased bout steps, but there was no statistically significant difference between groups. Among study completers, bout steps increased by 1921 ± 2729 steps a day. Those who received lifestyle goals were more satisfied with the intervention (p = 0.006 and wore the pedometer more often (p Conclusion In this six-week intervention, Lifestyle Goals group participants achieved increases in bout steps comparable to the

  4. Does an additional structured information program during the intensive care unit stay reduce anxiety in ICU patients?: a multicenter randomized controlled trial.

    Science.gov (United States)

    Fleischer, Steffen; Berg, Almuth; Behrens, Johann; Kuss, Oliver; Becker, Ralf; Horbach, Annegret; Neubert, Thomas R

    2014-01-01

    Communication and information in order to reduce anxiety in the intensive care unit (ICU) has been described as area needing improvement. Therefore, the aim of this trial was to evaluate whether a structured information program that intensifies information given in standard care process reduces anxiety in ICU patients. Multicenter, two-armed, non-blinded, parallel-group randomized controlled trial in hospitals in the cities of Marburg, Halle, and Stuttgart (Germany). The trial was performed in cardiac surgery, general surgery, and internal medicine ICUs. Two-hundred and eleven elective and non-elective ICU patients were enrolled in the study (intervention group, n = 104; control group, n = 107). The experimental intervention comprised a single episode of structured oral information that was given in addition to standard care and covered two main parts: (1) A more standardized part about predefined ICU specific aspects - mainly procedural, sensory and coping information, and (2) an individualized part about fears and questions of the patient. The control group received a non-specific episodic conversation of similar length additional to standard care. Both conversations took place at the beginning of the ICU stay and lasted 10-15 minutes. Study nurses administered both interventions. The primary outcome ICU-related anxiety (CINT-Score, 0-100 pts., higher scores indicate higher anxiety) was assessed after admission to a regular ward. The primary outcome could be measured in 82 intervention group participants and 90 control group participants resulting in mean values of 20.4 (SD 14.4) compared to 20.8 (SD 14.7) and a mean difference of -0.2 (CI 95% -4.5 to 4.1). A structured information intervention additional to standard care during ICU stay had no demonstrated additional benefit compared to an unspecific communication of similar duration. Reduction of anxiety in ICU patients will probably require more continuous approaches to information giving and

  5. Focused and Corrective Feedback Versus Structured and Supported Debriefing in a Simulation-Based Cardiac Arrest Team Training: A Pilot Randomized Controlled Study.

    Science.gov (United States)

    Kim, Ji-Hoon; Kim, Young-Min; Park, Seong Heui; Ju, Eun A; Choi, Se Min; Hong, Tai Yong

    2017-06-01

    The aim of the study was to compare the educational impact of two postsimulation debriefing methods-focused and corrective feedback (FCF) versus Structured and Supported Debriefing (SSD)-on team dynamics in simulation-based cardiac arrest team training. This was a pilot randomized controlled study conducted at a simulation center. Fourth-year medical students were randomly assigned to the FCF or SSD group, with each team composed of six students and a confederate. Each team participated in two simulations and the assigned debriefing (FCF or SSD) sessions and then underwent a test simulation. Two trained raters blindly assessed all of the recorded simulations using checklists. The primary outcome was the improvement in team dynamics scores between baseline and test simulation. The secondary outcomes were improvements before and after training in team clinical performance scores, self-assessed comprehension of and confidence in cardiac arrest management and team dynamics, as well as evaluations of the postsimulation debriefing intervention. In total, 95 students participated [FCF (8 teams, n = 47) and SSD (8 teams, n = 48)]. The SSD team dynamics score during the test simulation was higher than at baseline [baseline: 74.5 (65.9-80.9), test: 85.0 (71.9-87.6), P = 0.035]. However, there were no differences in the improvement in the team dynamics or team clinical performance scores between the two groups (P = 0.328, respectively). There was no significant difference in improvement in team dynamics scores during the test simulation compared with baseline between the SSD and FCF groups in a simulation-based cardiac arrest team training in fourth-year Korean medical students.

  6. Protein Engineering by Random Mutagenesis and Structure-Guided Consensus of Geobacillus stearothermophilus Lipase T6 for Enhanced Stability in Methanol

    Science.gov (United States)

    Dror, Adi; Shemesh, Einav; Dayan, Natali

    2014-01-01

    The abilities of enzymes to catalyze reactions in nonnatural environments of organic solvents have opened new opportunities for enzyme-based industrial processes. However, the main drawback of such processes is that most enzymes have a limited stability in polar organic solvents. In this study, we employed protein engineering methods to generate a lipase for enhanced stability in methanol, which is important for biodiesel production. Two protein engineering approaches, random mutagenesis (error-prone PCR) and structure-guided consensus, were applied in parallel on an unexplored lipase gene from Geobacillus stearothermophilus T6. A high-throughput colorimetric screening assay was used to evaluate lipase activity after an incubation period in high methanol concentrations. Both protein engineering approaches were successful in producing variants with elevated half-life values in 70% methanol. The best variant of the random mutagenesis library, Q185L, exhibited 23-fold-improved stability, yet its methanolysis activity was decreased by one-half compared to the wild type. The best variant from the consensus library, H86Y/A269T, exhibited 66-fold-improved stability in methanol along with elevated thermostability (+4.3°C) and a 2-fold-higher fatty acid methyl ester yield from soybean oil. Based on in silico modeling, we suggest that the Q185L substitution facilitates a closed lid conformation that limits access for both the methanol and substrate excess into the active site. The enhanced stability of H86Y/A269T was a result of formation of new hydrogen bonds. These improved characteristics make this variant a potential biocatalyst for biodiesel production. PMID:24362426

  7. Force limited random vibration testing: the computation of the semi-empirical constant C2 for a real test article and unknown supporting structure

    NARCIS (Netherlands)

    Wijker, Jacob J; Ellenbroek, Marcellinus Hermannus Maria; de Boer, Andries

    2015-01-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load),

  8. Feedback Both Helps and Hinders Learning: The Causal Role of Prior Knowledge

    Science.gov (United States)

    Fyfe, Emily R.; Rittle-Johnson, Bethany

    2016-01-01

    Feedback can be a powerful learning tool, but its effects vary widely. Research has suggested that learners' prior knowledge may moderate the effects of feedback; however, no causal link has been established. In Experiment 1, we randomly assigned elementary school children (N = 108) to a condition based on a crossing of 2 factors: induced strategy…

  9. Transformational Learning through Prior Learning Assessment

    Science.gov (United States)

    Stevens, Karen; Gerber, Dan; Hendra, Rick

    2010-01-01

    Upon graduation from University Without Walls (UWW), Robin said, "During first semester you told us that if we allowed it to, this experience [writing a prior learning portfolio] would change us. I was so angry with you for saying that because I liked who I was and didn't want to change. But you were right. And I'm glad." For the past 39…

  10. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    The description of real-life engineering structural systems is associated with some amount of uncertainty in specifying material properties, geometric parameters, boundary conditions and applied loads. In the context of structural dynamics it is necessary to consider random eigenvalue problems in order to account for these ...

  11. Single Image Superresolution Using Maximizing Self-Similarity Prior

    Directory of Open Access Journals (Sweden)

    Jianhong Li

    2015-01-01

    Full Text Available Single image superresolution (SISR requires only one low-resolution (LR image as its input which thus strongly motivates researchers to improve the technology. The property that small image patches tend to recur themselves across different scales is very important and widely used in image processing and computer vision community. In this paper, we develop a new approach for solving the problem of SISR by generalizing this property. The main idea of our approach takes advantage of a generic prior that assumes that a randomly selected patch in the underlying high-resolution (HR image should visually resemble as much as possible with some patch extracted from the input low-resolution (LR image. Observing the proposed prior, our approach deploys a cost function and applies an iterative scheme to estimate the optimal HR image. For solving the cost function, we introduce Gaussian mixture model (GMM to train on a sampled data set for approximating the joint probability density function (PDF of input image with different scales. Through extensive comparative experiments, this paper demonstrates that the visual fidelity of our proposed method is often superior to those generated by other state-of-the-art algorithms as determined through both perceptual judgment and quantitative measures.

  12. Prior storm experience moderates water surge perception and risk.

    Directory of Open Access Journals (Sweden)

    Gregory D Webster

    Full Text Available BACKGROUND: How accurately do people perceive extreme water speeds and how does their perception affect perceived risk? Prior research has focused on the characteristics of moving water that can reduce human stability or balance. The current research presents the first experiment on people's perceptions of risk and moving water at different speeds and depths. METHODS: Using a randomized within-person 2 (water depth: 0.45, 0.90 m ×3 (water speed: 0.4, 0.8, 1.2 m/s experiment, we immersed 76 people in moving water and asked them to estimate water speed and the risk they felt. RESULTS: Multilevel modeling showed that people increasingly overestimated water speeds as actual water speeds increased or as water depth increased. Water speed perceptions mediated the direct positive relationship between actual water speeds and perceptions of risk; the faster the moving water, the greater the perceived risk. Participants' prior experience with rip currents and tropical cyclones moderated the strength of the actual-perceived water speed relationship; consequently, mediation was stronger for people who had experienced no rip currents or fewer storms. CONCLUSIONS: These findings provide a clearer understanding of water speed and risk perception, which may help communicate the risks associated with anticipated floods and tropical cyclones.

  13. Structured lifestyle intervention based on a trans-cultural diabetes-specific nutrition algorithm (tDNA) in individuals with type 2 diabetes: a randomized controlled trial

    Science.gov (United States)

    Chee, Winnie S S; Gilcharan Singh, Harvinder Kaur; Hamdy, Osama; Mechanick, Jeffrey I; Lee, Verna K M; Barua, Ankur; Mohd Ali, Siti Zubaidah; Hussein, Zanariah

    2017-01-01

    Objective Trans-cultural diabetes nutrition algorithm (tDNA) was created by international task force and culturally customized for Malaysian population. This study was designed to evaluate its effectiveness versus usual diabetes care in primary care settings. Research design and methods We randomized 230 patients with overweight/obesity, type 2 diabetes, and glycated hemoglobin (A1c) 7%–11% to receive usual care (UC) or UC with tDNA for 6 months. The tDNA intervention consisted of structured low-calorie meal plan, diabetes-specific meal replacements, and increased physical activity. Participants were counseled either through motivational interviewing (tDNA-MI) or conventional counseling (tDNA-CC). The UC group received standard dietary and exercise advice through conventional counseling. All patients were followed for another 6 months after intervention. Results At 6 months, A1c decreased significantly in tDNA-MI (−1.1±0.1%, pdiabetes control and body weight in primary care setting. PMID:29435347

  14. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith

    1995-01-01

    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  15. The life in sight application study (LISA): design of a randomized controlled trial to assess the role of an assisted structured reflection on life events and ultimate life goals to improve quality of life of cancer patients

    NARCIS (Netherlands)

    Kruizinga, Renske; Scherer-Rath, Michael; Schilderman, Johannes B. A. M.; Sprangers, Mirjam A. G.; van Laarhoven, Hanneke W. M.

    2013-01-01

    It is widely recognized that spiritual care plays an important role in physical and psychosocial well-being of cancer patients, but there is little evidence based research on the effects of spiritual care. We will conduct a randomized controlled trial on spiritual care using a brief structured

  16. Apixaban in patients with atrial fibrillation and prior coronary artery disease: insights from the ARISTOTLE trial.

    Science.gov (United States)

    Bahit, Maria Cecilia; Lopes, Renato D; Wojdyla, Daniel M; Hohnloser, Stefan H; Alexander, John H; Lewis, Basil S; Aylward, Philip E; Verheugt, Freek W A; Keltai, Matyas; Diaz, Rafael; Hanna, Michael; Granger, Christopher B; Wallentin, Lars

    2013-12-10

    A substantial portion of patients with atrial fibrillation (AF) also have coronary artery disease (CAD) and are at risk for coronary events. Warfarin is known to reduce these events, but increase the risk of bleeding. We assessed the effects of apixaban compared with warfarin in AF patients with and without prior CAD. In ARISTOTLE, 18,201 patients with AF were randomized to apixaban or warfarin. History of CAD was defined as documented CAD, prior myocardial infarction, and/or history of coronary revascularization. We analyzed baseline characteristics and clinical outcomes of patients with and without prior CAD and compared outcomes by randomized treatment using Cox models. A total of 6639 (36.5%) patients had prior CAD. These patients were more often male, more likely to have prior stroke, diabetes, and hypertension, and more often received aspirin at baseline (42.2% vs. 24.5%). The effects of apixaban were similar among patients with and without prior CAD on reducing stroke or systemic embolism and death from any cause (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.71-1.27, P for interaction=0.12; HR 0.96, 95% CI 0.81-1.13, P for interaction=0.28). Rates of myocardial infarction were numerically lower with apixaban than warfarin among patients with and without prior CAD. The effect of apixaban on reducing major bleeding and intracranial hemorrhage was consistent in patients with and without CAD. In patients with AF, apixaban more often prevented stroke or systemic embolism and death and caused less bleeding than warfarin, regardless of the presence of prior CAD. Given the common occurrence of AF and CAD and the higher rates of cardiovascular events and death, our results indicate that apixaban may be a better treatment option than warfarin for these high-risk patients. © 2013.

  17. Aldrin at ASVC prior to grand opening

    Science.gov (United States)

    1997-01-01

    Apollo 11 Lunar Module Pilot Edward E. 'Buzz' Aldrin, Jr. and his wife, Lois, stand before a painting of an Apollo/Saturn V launch vehicle at the pad in the new Apollo/Saturn V Center (ASVC) at KSC prior to the gala grand opening ceremony for the facility that was held Jan. 8, 1997. The astronauts were invited to participate in the event, which also featured NASA Administrator Dan Goldin and KSC Director Jay Honeycutt. The ASVC also features several other Apollo program spacecraft component displays and multimedia presentations. The facility will be a part of the KSC bus tour that embarks from the KSC Visitor Center.

  18. The effects of a two-year randomized, controlled trial of whey protein supplementation on bone structure, IGF-1, and urinary calcium excretion in older postmenopausal women.

    Science.gov (United States)

    Zhu, Kun; Meng, Xingqiong; Kerr, Deborah A; Devine, Amanda; Solah, Vicky; Binns, Colin W; Prince, Richard L

    2011-09-01

    The effects of dietary protein on bone structure and metabolism have been controversial, with evidence for and against beneficial effects. Because no long-term randomized, controlled studies have been performed, a two-year study of protein supplementation in 219 healthy ambulant women aged 70 to 80 years was undertaken. Participants were randomized to either a high-protein drink containing 30 g of whey protein (n = 109) or a placebo drink identical in energy content, appearance, and taste containing 2.1 g of protein (n = 110). Both drinks provided 600 mg of calcium. Dual-energy X-ray absorptiometric (DXA) hip areal bone mineral density (aBMD), 24-hour urinary calcium excretion, and serum insulin-like growth factor 1 (IGF-1) were measured at baseline and at 1 and 2 years. Quantitative computed tomographic (QCT) hip volumetric bone mineral density (vBMD) and a femoral neck engineering strength analysis were undertaken at baseline and at 2 years. Baseline average protein intake was 1.1 g/kg of body weight per day. There was a significant decrease in hip DXA aBMD and QCT vBMD over 2 years with no between-group differences. Femoral neck strength was unchanged in either group over time. The 24-hour urinary calcium excretion increased significantly from baseline in both groups at 1 year but returned to baseline in the placebo group at 2 years, at which time the protein group had a marginally higher value. Compared with the placebo group, the protein group had significantly higher serum IGF-1 level at 1 and 2 years (7.3% to 8.0%, p women, 30 g of extra protein increased IGF-1 but did not have beneficial or deleterious effects on bone mass or strength. The effect of protein supplementation in populations with low dietary protein intake requires urgent attention. Copyright © 2011 American Society for Bone and Mineral Research.

  19. Prior knowledge-based approach for associating ...

    Science.gov (United States)

    Evaluating the potential human health and/or ecological risks associated with exposures to complex chemical mixtures in the ambient environment is one of the central challenges of chemical safety assessment and environmental protection. There is a need for approaches that can help to integrate chemical monitoring and bio-effects data to evaluate risks associated with chemicals present in the environment. We used prior knowledge about chemical-gene interactions to develop a knowledge assembly model for detected chemicals at five locations near two wastewater treatment plants. The assembly model was used to generate hypotheses about the biological impacts of the chemicals at each location. The hypotheses were tested using empirical hepatic gene expression data from fathead minnows exposed for 12 d at each location. Empirical gene expression data was also mapped to the assembly models to statistically evaluate the likelihood of a chemical contributing to the observed biological responses. The prior knowledge approach was able reasonably hypothesize the biological impacts at one site but not the other. Chemicals most likely contributing to the observed biological responses were identified at each location. Despite limitations to the approach, knowledge assembly models have strong potential for associating chemical occurrence with potential biological effects and providing a foundation for hypothesis generation to guide research and/or monitoring efforts relat

  20. Depth image enhancement using perceptual texture priors

    Science.gov (United States)

    Bang, Duhyeon; Shim, Hyunjung

    2015-03-01

    A depth camera is widely used in various applications because it provides a depth image of the scene in real time. However, due to the limited power consumption, the depth camera presents severe noises, incapable of providing the high quality 3D data. Although the smoothness prior is often employed to subside the depth noise, it discards the geometric details so to degrade the distance resolution and hinder achieving the realism in 3D contents. In this paper, we propose a perceptual-based depth image enhancement technique that automatically recovers the depth details of various textures, using a statistical framework inspired by human mechanism of perceiving surface details by texture priors. We construct the database composed of the high quality normals. Based on the recent studies in human visual perception (HVP), we select the pattern density as a primary feature to classify textures. Upon the classification results, we match and substitute the noisy input normals with high quality normals in the database. As a result, our method provides the high quality depth image preserving the surface details. We expect that our work is effective to enhance the details of depth image from 3D sensors and to provide a high-fidelity virtual reality experience.

  1. Improving Open Access through Prior Learning Assessment

    Directory of Open Access Journals (Sweden)

    Shuangxu Yin

    2013-01-01

    Full Text Available This paper explores and presents new data on how to improve open access in distance education through using prior learning assessments. Broadly there are three types of prior learning assessment (PLAR: Type-1 for prospective students to be allowed to register for a course; Type-2 for current students to avoid duplicating work-load to gain certification; and Type-3 mapping occupational skills as portfolio-needs analysis. In each of these some e-assessment can play a role, notably in Type-3 in distance education. Our previous research has been in Type-2 and we report the empirical results and challenges involved in practice. Moving beyond Type-2 we further report how e-Type-3 can improve our practice in the Open University of China—a very large ODL provider. We discuss the barriers and challenges being faced, and ways being explored to resolve these issues, to reduce the costs involved and to improve open access to learning.

  2. Random Projection Trees Revisited

    OpenAIRE

    Dhesi, Aman; Kar, Purushottam

    2010-01-01

    The Random Projection Tree structures proposed in [Freund-Dasgupta STOC08] are space partitioning data structures that automatically adapt to various notions of intrinsic dimensionality of data. We prove new results for both the RPTreeMax and the RPTreeMean data structures. Our result for RPTreeMax gives a near-optimal bound on the number of levels required by this data structure to reduce the size of its cells by a factor $s \\geq 2$. We also prove a packing lemma for this data structure. Our...

  3. Random matrix theory

    CERN Document Server

    Deift, Percy

    2009-01-01

    This book features a unified derivation of the mathematical theory of the three classical types of invariant random matrix ensembles-orthogonal, unitary, and symplectic. The authors follow the approach of Tracy and Widom, but the exposition here contains a substantial amount of additional material, in particular, facts from functional analysis and the theory of Pfaffians. The main result in the book is a proof of universality for orthogonal and symplectic ensembles corresponding to generalized Gaussian type weights following the authors' prior work. New, quantitative error estimates are derive

  4. Penalising Model Component Complexity: A Principled, Practical Approach to Constructing Priors

    KAUST Repository

    Simpson, Daniel

    2017-04-06

    In this paper, we introduce a new concept for constructing prior distributions. We exploit the natural nested structure inherent to many model components, which defines the model component to be a flexible extension of a base model. Proper priors are defined to penalise the complexity induced by deviating from the simpler base model and are formulated after the input of a user-defined scaling parameter for that model component, both in the univariate and the multivariate case. These priors are invariant to repa-rameterisations, have a natural connection to Jeffreys\\' priors, are designed to support Occam\\'s razor and seem to have excellent robustness properties, all which are highly desirable and allow us to use this approach to define default prior distributions. Through examples and theoretical results, we demonstrate the appropriateness of this approach and how it can be applied in various situations.

  5. Prior Knowledge in EFL Reading Comprehension: Omani Teachers’ Perspectives & Classroom Strategies

    Directory of Open Access Journals (Sweden)

    Yahya Al-Jahwari

    2015-01-01

    Full Text Available The study investigated three main aspects related to prior knowledge in EFL reading comprehension in Oman: teachers' view of the role of prior knowledge, the instructional strategies they use for activating students' prior knowledge, and the difficulties they face when activating students' prior knowledge. To this end, three instruments were used: a questionnaire, an observation checklist, and a semi-structured interview. The findings of the study showed a strong agreement of the role of prior knowledge in text comprehension, a heavy reliance on a limited number of techniques and a clear attribution of the difficulties to sources such as students’ limited linguistic competence and lack of adequate teacher training on schema theory and its instructional techniques. In light of the findings, some implications for EFL teachers, in-service teachers training, and for curriculum development are given.

  6. Random walks, random fields, and disordered systems

    CERN Document Server

    Černý, Jiří; Kotecký, Roman

    2015-01-01

    Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

  7. Self-prior strategy for organ reconstruction in fluorescence molecular tomography.

    Science.gov (United States)

    Zhou, Yuan; Chen, Maomao; Su, Han; Luo, Jianwen

    2017-10-01

    The purpose of this study is to propose a strategy for organ reconstruction in fluorescence molecular tomography (FMT) without prior information from other imaging modalities, and to overcome the high cost and ionizing radiation caused by the traditional structural prior strategy. The proposed strategy is designed as an iterative architecture to solve the inverse problem of FMT. In each iteration, a short time Fourier transform (STFT) based algorithm is used to extract the self-prior information in the space-frequency energy spectrum with the assumption that the regions with higher fluorescence concentration have larger energy intensity, then the cost function of the inverse problem is modified by the self-prior information, and lastly an iterative Laplacian regularization algorithm is conducted to solve the updated inverse problem and obtains the reconstruction results. Simulations and in vivo experiments on liver reconstruction are carried out to test the performance of the self-prior strategy on organ reconstruction. The organ reconstruction results obtained by the proposed self-prior strategy are closer to the ground truth than those obtained by the iterative Tikhonov regularization (ITKR) method (traditional non-prior strategy). Significant improvements are shown in the evaluation indexes of relative locational error (RLE), relative error (RE) and contrast-to-noise ratio (CNR). The self-prior strategy improves the organ reconstruction results compared with the non-prior strategy and also overcomes the shortcomings of the traditional structural prior strategy. Various applications such as metabolic imaging and pharmacokinetic study can be aided by this strategy.

  8. Lightness depends on immediately prior experience.

    Science.gov (United States)

    Annan, Vidal; Gilchrist, Alan

    2004-08-01

    The lightness hangover illusion is an unusually robust, long-lasting, prior-experience-based lightness effect. The effect occurs in the Mondrian world, a miniature chamber with interior walls covered with dark gray to black patches. The lightest patch in this scene, physically dark gray, looks white. When real whites and light grays are added to the scene, all the patches darken, but at an unusually slow rate. For several seconds, the white patches look self-luminous and the other patches continue to look very light. The luminosity fades and the other patches darken only after 2 min. We tested three possible explanations for this illusion: retinal adaptation, lightness persistence, and anchor persistence. The results clearly support anchor persistence, which is caused by the presence of steady patches, surfaces that retain their luminance values across scenes. The data also show that the size of the illusion varies directly with the number of these steady patches.

  9. Genome position specific priors for genomic prediction

    DEFF Research Database (Denmark)

    Brøndum, Rasmus Froberg; Su, Guosheng; Lund, Mogens Sandø

    2012-01-01

    Background The accuracy of genomic prediction is highly dependent on the size of the reference population. For small populations, including information from other populations could improve this accuracy. The usual strategy is to pool data from different populations; however, this has not proven...... as successful as hoped for with distantly related breeds. BayesRS is a novel approach to share information across populations for genomic predictions. The approach allows information to be captured even where the phase of SNP alleles and casual mutation alleles are reversed across populations, or the actual...... casual mutation is different between the populations but affects the same gene. Proportions of a four-distribution mixture for SNP effects in segments of fixed size along the genome are derived from one population and set as location specific prior proportions of distributions of SNP effects...

  10. Interplay of Prior Knowledge, Self-Regulation and Motivation in Complex Multimedia Learning Environments

    Science.gov (United States)

    Song, H. S.; Kalet, A. L.; Plass, J. L.

    2016-01-01

    This study examined the direct and indirect effects of medical clerkship students' prior knowledge, self-regulation and motivation on learning performance in complex multimedia learning environments. The data from 386 medical clerkship students from six medical schools were analysed using structural equation modeling. The structural model revealed…

  11. Autonomous Byte Stream Randomizer

    Science.gov (United States)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.

    2013-01-01

    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  12. Mammography test sets: reading location and prior images do not affect group performance.

    Science.gov (United States)

    Soh, B P; Lee, W B; McEntee, M F; Kench, P L; Reed, W M; Heard, R; Chakraborty, D P; Brennan, P C

    2014-04-01

    To examine how the location where reading takes place and the availability of prior images can affect performance in breast test-set reading. Under optimized viewing conditions, 10 expert screen readers each interpreted a reader-specific set of images containing 200 mammographic cases. Readers, randomly divided into two groups read images under one of two pairs of conditions: clinical read with prior images and laboratory read with prior images; laboratory read with prior images and laboratory read without prior images. Region-of-interest (ROI) figure-of-merit (FOM) was analysed using JAFROC software. Breast side-specific sensitivity and specificity were tested using Wilcoxon matched-pairs signed rank tests. Agreement between pairs of readings was measured using Kendall's coefficient of concordance. Group performances between test-set readings demonstrated similar ROI FOMs, sensitivity and specificity median values, and acceptable levels of agreement between pairs of readings were shown (W = 0.75-0.79, p reading conditions. On an individual reader level, two readers demonstrated significant decreases (p images were unavailable. Reading location had an inconsistent impact on individual performance. Reading location and availability of prior images did not significantly alter group performance. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  13. A MULTICENTER, BLIND, RANDOMIZED, PLACEBO-CONTROLLED STUDY OF THE SYMPTOM- AND STRUCTURE-MODIFYING EFFET OF ALFLUTOP IN PATIENTS WITH KNEE OSTEOARTHRITIS. REPORT 2: THE ASSESSMENT OF THE STRUCTURE-MODIFYING EFFECT OF THE DRUG

    Directory of Open Access Journals (Sweden)

    L. I. Alekseeva

    2014-01-01

    Full Text Available Objective. To evaluate the symptom- and structure-modifying effect of Alflutop compared to placebo (PL in patients with knee osteoarthritis (OA. Material and methods. The study included 90 patients with knee OA (according to the criteria of the Russian Association of Rheumatologists at the stage 2–3 (according to the Kellgren-Lawrence scale; pain score when walk- ing ≥ 40 mm (assessed using the visual analog scale. All the patients provided an informed consent. The patients were randomly divided into two groups: group 1 (n=45 received an intramuscular injection of 1 mL Alflutop for 20 days with 6-month intervals for 2 years (a total of 4 courses for 2 years; group 2 (n=45 received an injection of PL (iso- tonic sodium chloride solution in the same way. Ibuprofen at a dose of 600–1200 mg/day was administered as concomitant therapy. To evaluate the structure-modifying effect of Alflutop, X-ray of the knee joint was performed at the beginning and end of the study; the level of biochemical markers (CTX-II and COMP was determined at the beginning, after 3 months, and at the end of the study. A statistical analysis was performed using the Statistica 10 software package.Results. After the 2-year follow-up, a statistically significant negative trend was detected less frequently in the group of patients treated with Alflutop compared to the PL group (6.1 and 38.4%, respectively. The statistically significant delay in joint space narrowing was observed in patients who received Alflutop in contrast to patients who received PL (the numerical score of the joint space, the Wilcoxon test; p=0.0003. An increase in osteo- phyte size was observed in 72% of the patients receiving PL, and only in 27% of the patients receiving Alflutop (medial and lateral osteophytes of the femoral bone, the Wilcoxon test; p=0.0078; medial and lateral osteophytes of the shin bone, the Wilcoxon test; p=0.0001 and p=0.0039, respective- ly. Augmentation of subchondral

  14. The relevance of prior knowledge in learning and instructional design.

    Science.gov (United States)

    Hailikari, Telle; Katajavuori, Nina; Lindblom-Ylanne, Sari

    2008-10-15

    To determine how different types of prior knowledge (declarative and procedural) impact student achievement and how prior-knowledge assessment can be used as an instructional design tool. A questionnaire was developed based on the prior-knowledge model, which distinguishes between declarative and procedural knowledge. One hundred fifteen pharmacy students were tested prior to beginning 4 successive basic science courses and then prior to beginning a pharmaceutical chemistry course. Regression analysis was used to determine which type of knowledge was the best predictor of student achievement. The 4 course instructors were interviewed and their comments analyzed. Prior knowledge from previous courses significantly influenced student achievement. Procedural knowledge was especially related to student achievement. Instructors and students had mainly positive reactions towards the prior-knowledge tests. Students' prior knowledge should be taken into consideration in instructional design and curriculum planning. Furthermore, the results of prior-knowledge assessments may be used as a tool for student support in addressing areas of deficiency.

  15. Estimating functional brain networks by incorporating a modularity prior.

    Science.gov (United States)

    Qiao, Lishan; Zhang, Han; Kim, Minjeong; Teng, Shenghua; Zhang, Limei; Shen, Dinggang

    2016-11-01

    Functional brain network analysis has become one principled way of revealing informative organization architectures in healthy brains, and providing sensitive biomarkers for diagnosis of neurological disorders. Prior to any post hoc analysis, however, a natural issue is how to construct "ideal" brain networks given, for example, a set of functional magnetic resonance imaging (fMRI) time series associated with different brain regions. Although many methods have been developed, it is currently still an open field to estimate biologically meaningful and statistically robust brain networks due to our limited understanding of the human brain as well as complex noises in the observed data. Motivated by the fact that the brain is organized with modular structures, in this paper, we propose a novel functional brain network modeling scheme by encoding a modularity prior under a matrix-regularized network learning framework, and further formulate it as a sparse low-rank graph learning problem, which can be solved by an efficient optimization algorithm. Then, we apply the learned brain networks to identify patients with mild cognitive impairment (MCI) from normal controls. We achieved 89.01% classification accuracy even with a simple feature selection and classification pipeline, which significantly outperforms the conventional brain network construction methods. Moreover, we further explore brain network features that contributed to MCI identification, and discovered potential biomarkers for personalized diagnosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Coded Random Access

    DEFF Research Database (Denmark)

    Paolini, Enrico; Stefanovic, Cedomir; Liva, Gianluigi

    2015-01-01

    , in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of coded......The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered...... as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access...

  17. Febrile seizures prior to sudden cardiac death

    DEFF Research Database (Denmark)

    Stampe, Niels Kjær; Glinge, Charlotte; Jabbari, Reza

    2018-01-01

    Aims: Febrile seizure (FS) is a common disorder affecting 2-5% of children up to 5 years of age. The aim of this study was to determine whether FS in early childhood are over-represented in young adults dying from sudden cardiac death (SCD). Methods and results: We included all deaths (n = 4595...... with FS was sudden arrhythmic death syndrome (5/8; 62.5%). Conclusion: In conclusion, this study demonstrates a significantly two-fold increase in the frequency of FS prior to death in young SCD cases compared with the two control groups, suggesting that FS could potentially contribute in a risk......) nationwide and through review of all death certificates, we identified 245 SCD in Danes aged 1-30 years in 2000-09. Through the usage of nationwide registries, we identified all persons admitted with first FS among SCD cases (14/245; 5.7%) and in the corresponding living Danish population (71 027/2 369 785...

  18. Human papilloma virus infection prior to coitarche.

    Science.gov (United States)

    Doerfler, Daniela; Bernhaus, Astrid; Kottmel, Andrea; Sam, Christine; Koelle, Dieter; Joura, Elmar A

    2009-05-01

    The aim of our study was to determine the prevalence and the natural course of anogenital human papilloma virus (HPV) infections in girls prior to coitarche attending an outpatient gynecological unit. Specimens were taken from the anogenital region of 114 unselected 4-15 year old girls who were referred consecutively for various gynecological problems. Four girls were excluded because of sexual abuse. Low-risk HPV-deoxyribonucleic acid (DNA) was detected in 4 girls (3.6%) and high-risk HPV DNA in 15 children (13.6%). Two girls testing positive for HPV DNA had clinical apparent warts. After 1 year, 2 children had persistent high-risk HPV DNA, and in 1 case we found a switch from high-risk to low-risk HPV DNA. Subclinical genital low- and high-risk HPV infections are common in girls without any history of sexual abuse or sexual activity. We found persistence of genital HPV infection in children, which could be a reservoir for HPV-associated diseases later in life.

  19. Electroencephalographic slow waves prior to sleepwalking episodes.

    Science.gov (United States)

    Perrault, Rosemarie; Carrier, Julie; Desautels, Alex; Montplaisir, Jacques; Zadra, Antonio

    2014-12-01

    Recent studies have suggested that the onset of sleepwalking episodes may be preceded by fluctuations in slow-wave sleep electroencephalographic characteristics. However, whether or not such fluctuations are specific to sleepwalking episodes or generalized to all sleep-wake transitions in sleepwalkers remains unknown. The goal of this study was to compare spectral power for delta (1-4 Hz) and slow delta (0.5-1 Hz) as well as slow oscillation density before the onset of somnambulistic episodes versus non-behavioral awakenings recorded from the same group of sleepwalkers. A secondary aim was to describe the time course of observed changes in slow-wave activity and slow oscillations during the 3 min immediately preceding the occurrence of somnambulistic episodes. Twelve adult sleepwalkers were investigated polysomnographically during the course of one night. Slow-wave activity and slow oscillation density were significantly greater prior to patients' somnambulistic episodes as compared with non-behavioral awakenings. However, there was no evidence for a gradual increase over the 3 min preceding the episodes. Increased slow-wave activity and slow oscillation density appear to be specific to sleepwalking episodes rather than generalized to all sleep-wake transitions in sleepwalkers. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Data assimilation with improved prior models

    Science.gov (United States)

    Lu, F.; Tu, X.; Chorin, A. J.

    2016-12-01

    Due to computationally expensive forward models, ensemble filters often either use the full model with a small ensemble, or use a reduced model with a large ensemble. In either case, the sampling error or the model error poses a challenge to ensemble filter performance. Covariance localization and inflation techniques have been developed to ameliorate the errors. However, tuning localization and inflation is expensive, and they introduce further filter errors. We investigate an alternative approach of using improved reduced prior models. The improved reduced model is a non-Markovian model obtained by quantifying the model error using a discrete-time stochastic parametrization, so that it captures the statistical and dynamical features of the full model. The improved reduced model achieves good filter performance using a reasonable size of ensemble without any localization or inflation. Tests on the two-layer Lorenz 96 model show that an improved reduced model has better filter performance than the original reduced system with tuned localization and inflation, and it has comparable performance to the full system with a small ensemble and tuned localization and inflation.

  1. Obstetrics in Mexico prior to 1600.

    Science.gov (United States)

    Van Patten, N

    1932-03-01

    Surviving Indian codices and inscriptions, reports written down by the Spanish, and continuity of practice from pre-conquest times are the sources of knowledge about obstetrics in Mexico prior to 1600. Antenatal care included avoidance of exposure to heat, no sleep during the day, and plenty of nourishment, although certain dietary precautions were recommended. Moderate intercourse during the first trimester was permitted but prohibited near the time of parturition. In general, midwives counseled the prospective mother to eat well, to rest physically and mentally, and to engage very moderately in manual labor. Massage was given at regular intervals, and vapor baths were taken. Juices of medicinal plants were administered during labor both to expedite it and to relieve pain. Women assumed a squatting position during labor, which was also assisted by abdominal massage and the manual dilation of the vulva. If parturition was prolonged, pressure was applied by the midwife who used her feet for this purpose. The child was bathed immediately after birth. Lactation was prolonged among the Mexicans.

  2. Random thoughts

    Science.gov (United States)

    ajansen; kwhitefoot; panteltje1; edprochak; sudhakar, the

    2014-07-01

    In reply to the physicsworld.com news story “How to make a quantum random-number generator from a mobile phone” (16 May, http://ow.ly/xFiYc, see also p5), which describes a way of delivering random numbers by counting the number of photons that impinge on each of the individual pixels in the camera of a Nokia N9 smartphone.

  3. Sparse Multivariate Modeling: Priors and Applications

    DEFF Research Database (Denmark)

    Henao, Ricardo

    to use them as hypothesis generating tools. All of our models start from a family of structures, for instance factor models, directed acyclic graphs, classifiers, etc. Then we let them be selectively sparse as a way to provide them with structural fl exibility and interpretability. Finally, we complement...... modeling, a model for peptide-protein/protein-protein interactions called latent protein tree, a framework for sparse Gaussian process classification based on active set selection and a linear multi-category sparse classifier specially targeted to gene expression data. The thesis is organized to provide...

  4. Prior exercise and standing as strategies to circumvent sitting-induced leg endothelial dysfunction.

    Science.gov (United States)

    Morishima, Takuma; Restaino, Robert M; Walsh, Lauren K; Kanaley, Jill A; Padilla, Jaume

    2017-06-01

    We have previously shown that local heating or leg fidgeting can prevent prolonged sitting-induced leg endothelial dysfunction. However, whether physical activity prevents subsequent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that sitting-induced leg endothelial dysfunction would be prevented by prior exercise. We also examined if, in the absence of exercise, standing is an effective alternative strategy to sitting for conserving leg endothelial function. Fifteen young healthy subjects completed three randomized experimental trials: (1) sitting without prior exercise; (2) sitting with prior exercise; and (3) standing without prior exercise. Following baseline popliteal artery flow-mediated dilation (FMD) measurements, subjects maintained a supine position for 45 min in the sitting and standing trials, without prior exercise, or performed 45 min of leg cycling before sitting (i.e. sitting with prior exercise trial). Thereafter, subjects were positioned into a seated or standing position, according to the trial, for 3 h. Popliteal artery FMD measures were then repeated. Three hours of sitting without prior exercise caused a significant impairment in popliteal artery FMD (baseline: 3.8±0.5%, post-sitting: 1.5±0.5%, Pexercise (baseline: 3.8±0.5%, post-sitting: 3.6±0.7%, P>0.05). Three hours of standing did not significantly alter popliteal artery FMD (baseline: 4.1±0.4%, post-standing: 4.3±0.4%, P>0.05). In conclusion, prolonged sitting-induced leg endothelial dysfunction can be prevented by prior aerobic exercise. In addition, in the absence of exercise, standing represents an effective substitute to sitting for preserving leg conduit artery endothelial function. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  5. Hierachical pre-segmentation without prior knowledge

    NARCIS (Netherlands)

    Kuijper, Arjan; Florack, L.M.J.

    2001-01-01

    A new method to pre-segment images by means of a hierarchical description is proposed. This description is obtained from an investigation of the deep structure of a scale space image - the input image and the Gaussian filtered ones simultaneously. We concentrate on scale space critical points -

  6. Leveraging Prior Calculus Study with Embedded Review

    Science.gov (United States)

    Nikolov, Margaret C.; Withers, Wm. Douglas

    2016-01-01

    We propose a new course structure to address the needs of college students with previous calculus study but no course validations as an alternative to repeating the first year of calculus. Students are introduced directly to topics from Calculus III unpreceded by a formal review of topics from Calculus I or II, but with additional syllabus time…

  7. Polyenergetic known-component reconstruction without prior shape models

    Science.gov (United States)

    Zhang, C.; Zbijewski, W.; Zhang, X.; Xu, S.; Stayman, J. W.

    2017-03-01

    Purpose: Previous work has demonstrated that structural models of surgical tools and implants can be integrated into model-based CT reconstruction to greatly reduce metal artifacts and improve image quality. This work extends a polyenergetic formulation of known-component reconstruction (Poly-KCR) by removing the requirement that a physical model (e.g. CAD drawing) be known a priori, permitting much more widespread application. Methods: We adopt a single-threshold segmentation technique with the help of morphological structuring elements to build a shape model of metal components in a patient scan based on initial filtered-backprojection (FBP) reconstruction. This shape model is used as an input to Poly-KCR, a formulation of known-component reconstruction that does not require a prior knowledge of beam quality or component material composition. An investigation of performance as a function of segmentation thresholds is performed in simulation studies, and qualitative comparisons to Poly-KCR with an a priori shape model are made using physical CBCT data of an implanted cadaver and in patient data from a prototype extremities scanner. Results: We find that model-free Poly-KCR (MF-Poly-KCR) provides much better image quality compared to conventional reconstruction techniques (e.g. FBP). Moreover, the performance closely approximates that of Poly- KCR with an a prior shape model. In simulation studies, we find that imaging performance generally follows segmentation accuracy with slight under- or over-estimation based on the shape of the implant. In both simulation and physical data studies we find that the proposed approach can remove most of the blooming and streak artifacts around the component permitting visualization of the surrounding soft-tissues. Conclusion: This work shows that it is possible to perform known-component reconstruction without prior knowledge of the known component. In conjunction with the Poly-KCR technique that does not require knowledge of

  8. Optical physics: Clear directions for random lasers

    Science.gov (United States)

    Wiersma, Diederik S.

    2016-11-01

    Random lasers use disordered structures to produce light, which is usually emitted in many directions. A random laser that can produce a collimated beam offers a wide range of applications, from imaging to security scanning.

  9. Effect of random structure on permeability and heat transfer characteristics for flow in 2D porous medium based on MRT lattice Boltzmann method

    Science.gov (United States)

    Yang, PeiPei; Wen, Zhi; Dou, RuiFeng; Liu, Xunliang

    2016-08-01

    Flow and heat transfer through a 2D random porous medium are studied by using the lattice Boltzmann method (LBM). For the random porous medium, the influence of disordered cylinder arrangement on permeability and Nusselt number are investigated. Results indicate that the permeability and Nusselt number for different cylinder locations are unequal even with the same number and size of cylinders. New correlations for the permeability and coefficient b‧Den of the Forchheimer equation are proposed for random porous medium composed of Gaussian distributed circular cylinders. Furthermore, a general set of heat transfer correlations is proposed and compared with existing experimental data and empirical correlations. Our results show that the Nu number increases with the increase of the porosity, hence heat transfer is found to be accurate considering the effect of porosity.

  10. Prior Knowledge and Complacency in New Product Learning.

    OpenAIRE

    Wood, Stacy L; Lynch, John G, Jr

    2002-01-01

    Our research examines the role of prior knowledge in learning new product information. Three studies demonstrate that, compared to consumers with lower prior knowledge, those with higher prior knowledge learn less about a new product. Further, higher knowledge consumers are able to learn more but learn less due to motivational deficits; inferior learning of new product information by those with higher prior knowledge is caused by inattention at encoding rather than reconstructive errors at re...

  11. Frequency of stress testing to document ischemia prior to elective percutaneous coronary intervention.

    Science.gov (United States)

    Lin, Grace A; Dudley, R Adams; Lucas, F L; Malenka, David J; Vittinghoff, Eric; Redberg, Rita F

    2008-10-15

    Guidelines call for documenting ischemia in patients with stable coronary artery disease prior to elective percutaneous coronary intervention (PCI). To determine the frequency and predictors of stress testing prior to elective PCI in a Medicare population. Retrospective, observational cohort study using claims data from a 20% random sample of 2004 Medicare fee-for-service beneficiaries aged 65 years or older who had an elective PCI (N = 23 887). Percentage of patients who underwent stress testing within 90 days prior to elective PCI; variation in stress testing prior to PCI across 306 hospital referral regions; patient, physician, and hospital characteristics that predicted the appropriate use of stress testing prior to elective PCI. In the United States, 44.5% (n = 10 629) of patients underwent stress testing within the 90 days prior to elective PCI. There was wide regional variation among the hospital referral regions with stress test rates ranging from 22.1% to 70.6% (national mean, 44.5%; interquartile range, 39.0%-50.9%). Female sex (adjusted odds ratio [AOR], 0.91; 95% confidence interval [CI], 0.86-0.97), age of 85 years or older (AOR, 0.83; 95% CI, 0.72-0.95), a history of congestive heart failure (AOR, 0.85; 95% CI, 0.79-0.92), and prior cardiac catheterization (AOR, 0.45; 95% CI, 0.38-0.54) were associated with a decreased likelihood of prior stress testing. A history of chest pain (AOR, 1.28; 95% CI, 1.09-1.54) and black race (AOR, 1.26; 95% CI, 1.09-1.46) increased the likelihood of stress testing prior to PCI. Patients treated by physicians performing 150 or more PCIs per year were less likely to have stress testing prior to PCI (AOR, 0.84; 95% CI, 0.77-0.93). No hospital characteristics were associated with receipt of stress testing. The majority of Medicare patients with stable coronary artery disease do not have documentation of ischemia by noninvasive testing prior to elective PCI.

  12. Prior Mental Fatigue Impairs Marksmanship Decision Performance

    Science.gov (United States)

    Head, James; Tenan, Matthew S.; Tweedell, Andrew J.; LaFiandra, Michael E.; Morelli, Frank; Wilson, Kyle M.; Ortega, Samson V.; Helton, William S.

    2017-01-01

    Purpose: Mental fatigue has been shown to impair subsequent physical performance in continuous and discontinuous exercise. However, its influence on subsequent fine-motor performance in an applied setting (e.g., marksmanship for trained soldiers) is relatively unknown. The purpose of this study was to investigate whether prior mental fatigue influences subsequent marksmanship performance as measured by shooting accuracy and judgment of soldiers in a live-fire scenario. Methods: Twenty trained infantry soldiers engaged targets after completing either a mental fatigue or control intervention in a repeated measure design. Heart rate variability and the NASA-TLX were used to gauge physiological and subjective effects of the interventions. Target hit proportion, projectile group accuracy, and precision were used to measure marksmanship accuracy. Marksmanship accuracy was assessed by measuring bullet group accuracy (i.e., how close a group of shots are relative to center of mass) and bullet group precision (i.e., how close are each individual shot to each other). Additionally, marksmanship decision accuracy (correctly shooting vs. correctly withholding shot) when engaging targets was used to examine marksmanship performance. Results: Soldiers rated the mentally fatiguing task (59.88 ± 23.7) as having greater mental workload relative to the control intervention [31.29 ± 12.3, t(19) = 1.72, p < 0.001]. Additionally, soldiers completing the mental fatigue intervention (96.04 ± = 37.1) also had lower time-domain (standard deviation of normal to normal R-R intervals) heart rate variability relative to the control [134.39 ± 47.4, t(18) = 3.59, p < 0.001]. Projectile group accuracy and group precision failed to show differences between interventions [t(19) = 0.98, p = 0.34, t(19) = 0.18, p = 0.87, respectively]. Marksmanship decision errors significantly increased after soldiers completed the mental fatigue intervention (48% ± 22.4) relative to the control intervention [M

  13. Universal randomness

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, Viktor S [Landau Institute for Theoretical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-03-31

    In the last two decades, it has been established that a single universal probability distribution function, known as the Tracy-Widom (TW) distribution, in many cases provides a macroscopic-level description of the statistical properties of microscopically different systems, including both purely mathematical ones, such as increasing subsequences in random permutations, and quite physical ones, such as directed polymers in random media or polynuclear crystal growth. In the first part of this review, we use a number of models to examine this phenomenon at a simple qualitative level and then consider the exact solution for one-dimensional directed polymers in a random environment, showing that free energy fluctuations in such a system are described by the universal TW distribution. The second part provides detailed appendix material containing the necessary mathematical background for the first part. (reviews of topical problems)

  14. Random triangles

    OpenAIRE

    Matula, Dominik

    2013-01-01

    The author summarizes some previous results concerning random triangles. He describes the Gaussian triangle and random triangles whose vertices lie in a unit n-dimensional ball, in a rectangle or in a general bounded convex set. In the second part, the author deals with an inscribed triangle in a triangle - let ABC be an equilateral triangle and let M, N, O be three points, each laying on one side of the ABC. We call MNO inscribed triangle (in an equi- laterral triangle). The median triangle ...

  15. Random matrices

    CERN Document Server

    Mehta, Madan Lal

    1990-01-01

    Since the publication of Random Matrices (Academic Press, 1967) so many new results have emerged both in theory and in applications, that this edition is almost completely revised to reflect the developments. For example, the theory of matrices with quaternion elements was developed to compute certain multiple integrals, and the inverse scattering theory was used to derive asymptotic results. The discovery of Selberg's 1944 paper on a multiple integral also gave rise to hundreds of recent publications. This book presents a coherent and detailed analytical treatment of random matrices, leading

  16. A randomized controlled pilot study into the effects of a restricted elimination diet on family structure in families with ADHD and ODD

    NARCIS (Netherlands)

    Pelsser, L.M.; Steijn, van D.J.; Frankena, K.; Toorman, J.; Buitelaar, J.K.; Rommelse, N.N.

    2013-01-01

    Behavioural improvements of children with attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) following a restricted elimination diet (RED), may be due to concurrent changes in family environment. Methods: Twenty-four children with ADHD, were randomized to either

  17. Bayes factors for testing inequality constrained hypotheses: Issues with prior specification.

    Science.gov (United States)

    Mulder, Joris

    2014-02-01

    Several issues are discussed when testing inequality constrained hypotheses using a Bayesian approach. First, the complexity (or size) of the inequality constrained parameter spaces can be ignored. This is the case when using the posterior probability that the inequality constraints of a hypothesis hold, Bayes factors based on non-informative improper priors, and partial Bayes factors based on posterior priors. Second, the Bayes factor may not be invariant for linear one-to-one transformations of the data. This can be observed when using balanced priors which are centred on the boundary of the constrained parameter space with a diagonal covariance structure. Third, the information paradox can be observed. When testing inequality constrained hypotheses, the information paradox occurs when the Bayes factor of an inequality constrained hypothesis against its complement converges to a constant as the evidence for the first hypothesis accumulates while keeping the sample size fixed. This paradox occurs when using Zellner's g prior as a result of too much prior shrinkage. Therefore, two new methods are proposed that avoid these issues. First, partial Bayes factors are proposed based on transformed minimal training samples. These training samples result in posterior priors that are centred on the boundary of the constrained parameter space with the same covariance structure as in the sample. Second, a g prior approach is proposed by letting g go to infinity. This is possible because the Jeffreys-Lindley paradox is not an issue when testing inequality constrained hypotheses. A simulation study indicated that the Bayes factor based on this g prior approach converges fastest to the true inequality constrained hypothesis. © 2013 The British Psychological Society.

  18. The use of misoprostol for cervical priming prior to hysteroscopy: a systematic review and analysis

    Directory of Open Access Journals (Sweden)

    Hua Y

    2016-09-01

    Full Text Available Ying Hua, Wenwen Zhang, Xiaoli Hu, Ansu Yang, Xueqiong Zhu Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China Abstract: The effects of misoprostol use on cervical priming prior to hysteroscopy have been controversial. Therefore, a systematic literature review and meta-analysis of studies were conducted to assess the effect of misoprostol on cervical priming prior to hysteroscopy. All studies published before July 2014 with data related to the use of misoprostol for cervical priming compared with placebo or no medication prior to hysteroscopy, were identified. Twenty-five randomized controlled trials involving 2,203 females were systematically analyzed. The results showed that, compared with placebo or no medication, the use of misoprostol prior to hysteroscopy led to a significant relief of the need for cervical dilatation, resulted in a significantly greater cervical width, had fewer hysteroscopy complications, and mild and insignificant side effects. Subgroup analyses revealed that the regimen of 200 or 400 µg vaginal misoprostol may be a simple and effective method for cervical priming, especially prior to operative hysteroscopy. Keywords: misoprostol, hysteroscopy, cervical priming, cervical dilatation, complications, systematic review 

  19. SAR moving object imaging using sparsity imposing priors

    Science.gov (United States)

    Önhon, N. Özben; Çetin, Müjdat

    2017-12-01

    Synthetic aperture radar (SAR) returns from a scene with motion can be viewed as data from a stationary scene, but with phase errors due to motion. Based on this perspective, we formulate the problem of SAR imaging of motion-containing scenes as one of joint imaging and phase error compensation. The proposed method is based on the minimization of a cost function which involves sparsity-imposing regularization terms on the reflectivity field to be imaged, considering that it admits a sparse representation as well as on the spatial structure of the motion-related phase errors, reflecting the assumption that only a small percentage of the entire scene contains moving objects. To incorporate the spatial structure of the phase errors into the problem, we provide three different sparsity-enforcing prior terms. In order to achieve computational gains, we also present a two-step version of our approach, which first determines regions of interest that are likely to contain the moving objects and then applies our sparsity-driven approach for joint image reconstruction and autofocusing in such a spatially constrained setting. Our preliminary experiments demonstrate the effectiveness of this new moving target SAR imaging approach.

  20. [Geriatric assessment prior to oncological therapy].

    Science.gov (United States)

    Wedding, U

    2013-06-01

    Ageing is the single most important risk factor for cancer. This is also true for most cancer diseases of the genitourinary tract. In combination with the demographic changes in Germany and most other countries, the consequence is a substantial increase in the number of elderly patients with cancer. Most therapies in oncology have a high risk for toxic side effects. Ageing is a very heterogeneous process. The chronological age of a patient insufficiently reflects the individual resources, deficits and risk factors but this can be assessed by a structured geriatric assessment. Integration of geriatric assessment into oncological treatment decisions is still low and is one of the major tasks in cancer care in the future.

  1. Age effects on spectral electroencephalogram activity prior to dream recall.

    Science.gov (United States)

    Chellappa, Sarah L; Münch, Mirjam; Knoblauch, Vera; Cajochen, Christian

    2012-06-01

    Ageing is associated with marked changes in sleep timing, structure and electroencephalographic (EEG) activity. Older people exhibit less slow-wave and spindle activity during non-rapid eye movement (NREM) sleep, together with attenuated levels of rapid eye movement (REM) sleep as compared to young individuals. However, the extent to which these age-related changes in sleep impact on dream processing remains largely unknown. Here we investigated NREM and REM sleep EEG activity prior to dream recall and no recall in 17 young (20-31 years) and 15 older volunteers (57-74 years) during a 40 h multiple nap protocol. Dream recall was assessed immediately after each nap. During NREM sleep prior to dream recall, older participants displayed higher frontal EEG delta activity (1-3 Hz) and higher centro-parietal sigma activity (12-15 Hz) than the young volunteers. Conversely, before no recall, older participants had less frontal-central delta activity and less sigma activity in frontal, central and parietal derivations than the young participants. REM sleep was associated to age-related changes, such that older participants had less frontal-central alpha (10-12 Hz) and beta (16-19 Hz) activity, irrespective of dream recall and no recall. Our data indicate that age-related differences in dream recall seem to be directly coupled to specific frequency and topography EEG patterns, particularly during NREM sleep. Thus, the spectral correlates of dreaming can help to understand the cortical pathways of dreaming. © 2011 European Sleep Research Society.

  2. Effects of stereospecific positioning of fatty acids in triacylglycerol structures in native and randomized fats: a review of their nutritional implications

    Directory of Open Access Journals (Sweden)

    Sundram Kalyana

    2007-07-01

    Full Text Available Abstract Most studies on lipid lowering diets have focused on the total content of saturated, polyunsaturated and monounsaturated fatty acids. However, the distribution of these fatty acids on the triacylglycerol (TAG molecule and the molecular TAG species generated by this stereospecificity are characteristic for various native dietary TAGs. Fat randomization or interesterification is a process involving the positional redistribution of fatty acids, which leads to the generation of new TAG molecular species. A comparison between native and randomized TAGs is the subject of this review with regards to the role of stereospecificity of fatty acids in metabolic processing and effects on fasting lipids and postprandial lipemia. The positioning of unsaturated versus saturated fatty acids in the sn-2 position of TAGs indicate differences in early metabolic processing and postprandial clearance, which may explain modulatory effects on atherogenecity and thrombogenecity. Both human and animal studies are discussed with implications for human health.

  3. Comparison of no-prior and soft-prior regularization in biomedical microwave imaging

    Directory of Open Access Journals (Sweden)

    Amir H Golnabi

    2011-01-01

    Full Text Available Microwave imaging for medical applications is attractive because the range of dielectric properties of different soft tissues can be substantial. Breast cancer detection and monitoring of treatment response are areas where this technology could be important because of the contrast between normal and malignant tissue. Unfortunately, the technique is unable to achieve the high spatial resolution at depth in tissue which is available from other conventional modalities such as x-ray computed tomography (CT or magnetic resonance imaging (MRI. We have incorporated a soft-prior regularization strategy within our microwave reconstruction algorithm and compared it with the images obtained with traditional no-prior (Levenberg-Marquardt regularization. Initial simulation and phantom results show a significant improvement of the recovered electrical properties. Specifically, errors in the microwave property estimates were improved by as much as 95%. The effects of a false-inclusion region were also evaluated and the results show that a small residual property bias of 6% in permittivity and 15% in conductivity can occur that does not otherwise degrade the property recovery accuracy of inclusions that actually exist. The work sets the stage for integrating microwave imaging with MR for improved resolution and functional imaging of the breast in the future.

  4. A Structured, Manual-Based Low-Level Intervention vs. Treatment as Usual Evaluated in a Randomized Controlled Trial for Adolescents with Extreme Obesity - the STEREO Trial

    Directory of Open Access Journals (Sweden)

    Yvonne Mühlig

    2017-08-01

    Full Text Available Background: To compare efficacy and safety of a manual-based low-level psychological intervention with treatment as usual (weight loss treatment. Methods: A two-armed randomized controlled trial without blinding and computer-based stratified block randomization included adolescents and young adults (14.0-24.9 years with a BMI ≥ 30 kg/m2 at five German university hospitals. Primary outcomes were adherence (participation rate ≥ 5/6 sessions and quality of life (DISABKIDS-37 6 months after randomization. Secondary outcomes included depression, self-esteem, and perceived stress scores. Results: Of 397 screened adolescents, 119 (mean BMI 40.4 ± 7.0 kg/m2, 49.6% female were randomized to the manual-based low-level intervention (n = 59 or treatment as usual (n = 60. We observed no group difference for adherence (absolute risk reduction 0.4%, 95% CI -14.7% to 15.5%; p = 1.0 or health-related quality of life (score difference 8.1, 95% CI -2.1 to 18.3; p = 0.11. Among all secondary outcomes, we detected explorative evidence for an effect on the DISABKIDS-37 ‘social exclusion' subscale (score difference 15.5; 95% CI 1.6-29.4; p = 0.03. 18/19 adverse events occurred in 26 participants, none were classified as serious. Conclusion: Adherence to a coping-oriented intervention was comparable to weight loss treatment, although it was weak in both interventions. Psychological interventions may help to overcome social isolation; further confirmation is required.

  5. Information Propagation in Prior-Image-Based Reconstruction.

    Science.gov (United States)

    Stayman, J Webster; Prince, Jerry L; Siewerdsen, Jeffrey H

    Advanced reconstruction methods for computed tomography include sophisticated forward models of the imaging system that capture the pertinent physical processes affecting the signal and noise in projection measurements. However, most do little to integrate prior knowledge of the subject - often relying only on very general notions of local smoothness or edges. In many cases, as in longitudinal surveillance or interventional imaging, a patient has undergone a sequence of studies prior to the current image acquisition that hold a wealth of prior information on patient-specific anatomy. While traditional techniques tend to treat each data acquisition as an isolated event and disregard such valuable patient-specific prior information, some reconstruction methods, such as PICCS[1] and PIR-PLE[2], can incorporate prior images into a reconstruction objective function. Inclusion of such information allows for dramatic reduction in the data fidelity requirements and more robustly accommodate substantial undersampling and exposure reduction with consequent benefits to imaging speed and reduced radiation dose. While such prior-image-based methods offer tremendous promise, the introduction of prior information in the reconstruction raises significant concern regarding the accurate representation of features in the image and whether those features arise from the current data acquisition or from the prior images. In this work we propose a novel framework to analyze the propagation of information in prior-image-based reconstruction by decomposing the estimation into distinct components supported by the current data acquisition and by the prior image. This decomposition quantifies the contributions from prior and current data as a spatial map and can trace specific features in the image to their source. Such "information source maps" can potentially be used as a check on confidence that a given image feature arises from the current data or from the prior and to more quantitatively

  6. Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic (ECoG Signals

    Directory of Open Access Journals (Sweden)

    Zuoguan eWang

    2011-11-01

    Full Text Available Brain-computer interfaces (BCIs use brain signals to convey a user's intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG recordings from the surface of the brain in humans can give information about kinematic parameters (eg{} hand velocity or finger flexion. The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the anatomic constraints and dynamic constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS. Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation.

  7. Quantifying randomness in real networks

    Science.gov (United States)

    Orsini, Chiara; Dankulov, Marija M.; Colomer-de-Simón, Pol; Jamakovic, Almerima; Mahadevan, Priya; Vahdat, Amin; Bassler, Kevin E.; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-10-01

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks--the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain--and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs.

  8. Modeling the effects of prior infection on vaccine efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.J.; Forrest, S.; Ackley, D.H. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Computer Science; Perelson, A.S. [Los Alamos National Lab., NM (United States)

    1997-11-01

    We performed computer simulations to study the effects of prior infection on vaccine efficacy. We injected three antigens sequentially. The first antigen, designated the prior, represented a prior infection or vaccination. The second antigen, the vaccine, represented a single component of the trivalent influenza vaccine. The third antigen, the epidemic, represented challenge by an epidemic strain. For a fixed vaccine to epidemic strain cross-reactivities to the vaccine and to the epidemic strains. We found that, for many cross-reactivities, vaccination, when it had been preceded by a prior infection, provided more protection than vaccination alone. However, at some cross-reactivities, the prior infection reduced protection by clearing the vaccine before it had the chance to produce protective memory. The cross-reactivities between the prior, vaccine and epidemic strains played a major role in determining vaccine efficacy. This work has applications to understanding vaccination against viruses such as influenza that are continually mutating.

  9. Non-negative matrix factorization with Gaussian process priors

    DEFF Research Database (Denmark)

    Schmidt, Mikkel Nørgaard; Laurberg, Hans

    2008-01-01

    We present a general method for including prior knowledge in a nonnegative matrix factorization (NMF), based on Gaussian process priors. We assume that the nonnegative factors in the NMF are linked by a strictly increasing function to an underlying Gaussian process specified by its covariance...... function. This allows us to find NMF decompositions that agree with our prior knowledge of the distribution of the factors, such as sparseness, smoothness, and symmetries. The method is demonstrated with an example from chemical shift brain imaging....

  10. Spectrally Consistent Satellite Image Fusion with Improved Image Priors

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Aanæs, Henrik; Jensen, Thomas B.S.

    2006-01-01

    Here an improvement to our previous framework for satellite image fusion is presented. A framework purely based on the sensor physics and on prior assumptions on the fused image. The contributions of this paper are two fold. Firstly, a method for ensuring 100% spectrally consistency is proposed......, even when more sophisticated image priors are applied. Secondly, a better image prior is introduced, via data-dependent image smoothing....

  11. Variational segmentation problems using prior knowledge in imaging and vision

    DEFF Research Database (Denmark)

    Fundana, Ketut

    This dissertation addresses variational formulation of segmentation problems using prior knowledge. Variational models are among the most successful approaches for solving many Computer Vision and Image Processing problems. The models aim at finding the solution to a given energy functional defined......, prior knowledge is needed to obtain the desired solution. The introduction of shape priors in particular, has proven to be an effective way to segment objects of interests. Firstly, we propose a prior-based variational segmentation model to segment objects of interest in image sequences, that can deal...

  12. Crowdsourcing prior information to improve study design and data analysis.

    Science.gov (United States)

    Chrabaszcz, Jeffrey S; Tidwell, Joe W; Dougherty, Michael R

    2017-01-01

    Though Bayesian methods are being used more frequently, many still struggle with the best method for setting priors with novel measures or task environments. We propose a method for setting priors by eliciting continuous probability distributions from naive participants. This allows us to include any relevant information participants have for a given effect. Even when prior means are near-zero, this method provides a principle way to estimate dispersion and produce shrinkage, reducing the occurrence of overestimated effect sizes. We demonstrate this method with a number of published studies and compare the effect of different prior estimation and aggregation methods.

  13. Crowdsourcing prior information to improve study design and data analysis.

    Directory of Open Access Journals (Sweden)

    Jeffrey S Chrabaszcz

    Full Text Available Though Bayesian methods are being used more frequently, many still struggle with the best method for setting priors with novel measures or task environments. We propose a method for setting priors by eliciting continuous probability distributions from naive participants. This allows us to include any relevant information participants have for a given effect. Even when prior means are near-zero, this method provides a principle way to estimate dispersion and produce shrinkage, reducing the occurrence of overestimated effect sizes. We demonstrate this method with a number of published studies and compare the effect of different prior estimation and aggregation methods.

  14. Random walks in a random environment

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Random walks as well as diffusions in random media are considered. Methods are developed that allow one to establish large deviation results for both the 'quenched' and the 'averaged' case. Keywords. Large deviations; random walks in a random environment. 1. Introduction. A random walk on Zd is a stochastic ...

  15. Random cascades on wavelet trees and their use in analyzing and modeling natural images

    Science.gov (United States)

    Wainwright, Martin J.; Simoncelli, Eero P.; Willsky, Alan S.

    2000-12-01

    We develop a new class of non-Gaussian multiscale stochastic processes defined by random cascades on trees of wavelet or other multiresolution coefficients. These cascades reproduce a rich semi-parametric class of random variables known as Gaussian scale mixtures. We demonstrate that this model class can accurately capture the remarkably regular and non- Gaussian features of natural images in a parsimonious fashion, involving only a small set of parameters. In addition, this model structure leads to efficient algorithms for image processing. In particular, we develop a Newton- like algorithm for MAP estimation that exploits very fast algorithm for linear-Gaussian estimation on trees, and hence is efficient. On the basis of this MAP estimator, we develop and illustrate a denoising technique that is based on a global prior model, and preserves the structure of natural images.

  16. Variational Infinite Hidden Conditional Random Fields

    NARCIS (Netherlands)

    Bousmalis, Konstantinos; Zafeiriou, Stefanos; Morency, Louis-Philippe; Pantic, Maja; Ghahramani, Zoubin

    2015-01-01

    Hidden conditional random fields (HCRFs) are discriminative latent variable models which have been shown to successfully learn the hidden structure of a given classification problem. An Infinite hidden conditional random field is a hidden conditional random field with a countably infinite number of

  17. Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 3: Deterministic and random vibrations of exemplary system

    National Research Council Canada - National Science Library

    M. Podworna; M. Klasztorny

    2014-01-01

    ...) bridge/track structure/high-speed train system (BTT), developed in Part 2, advanced computer algorithms for the BTT numerical modelling and simulation as well as a computer programme to simulate vertical vibrations of BTT systems are developed...

  18. Enhancement of Ag nanoparticles concentration by prior ion implantation

    Science.gov (United States)

    Mu, Xiaoyu; Wang, Jun; Liu, Changlong

    2017-09-01

    Thermally grown SiO2 layer on Si substrates were singly or sequentially implanted with Zn or Cu and Ag ions at the same fluence of 2 × 1016/cm2. The profiles of implanted species, structure, and spatial distribution of the formed nanoparticles (NPs) have been characterized by the cross-sectional transmission electron microscope (XTEM) and Rutherford backscattering spectrometry (RBS). It is found that pre-implantation of Zn or Cu ions could suppress the self sputtering of Ag atoms during post Ag ion implantation, which gives rise to fabrication of Ag NPs with a high density. Moreover, it has also been demonstrated that the suppressing effect strongly depends on the applied energy and mobility of pre-implanted ions. The possible mechanism for the enhanced Ag NPs concentration has been discussed in combination with SRIM simulations. Both vacancy-like defects acting as the increased nucleation sites for Ag NPs and a high diffusivity of prior implanted ions in SiO2 play key roles in enhancing the deposition of Ag implants.

  19. Evaluation of the efficacy and effectiveness of a structured disorder tailored psychotherapy in ADHD in adults: study protocol of a randomized controlled multicentre trial.

    Science.gov (United States)

    Philipsen, Alexandra; Graf, Erika; Tebartz van Elst, Ludger; Jans, Thomas; Warnke, Andreas; Hesslinger, Bernd; Ebert, Dieter; Gerlach, Manfred; Matthies, Swantje; Colla, Michael; Jacob, Christian; Sobanski, Esther; Alm, Barbara; Rösler, Michael; Ihorst, Gabriele; Gross-Lesch, Silke; Gentschow, Laura; Kis, Bernhard; Huss, Michael; Lieb, Klaus; Schlander, Michael; Berger, Mathias

    2010-12-01

    ADHD is a serious risk factor for co-occurring psychiatric disorders and negative psychosocial consequences in adulthood. Previous trials on psychotherapeutic concepts for adult ADHD are based on behavioural (cognitive behavioural and dialectical behavioural) psychotherapeutic approaches and showed significant effects. The aim of our study group (COMPAS) is to carry out a first randomized and controlled multicentre study to evaluate the effects of a disorder tailored psychotherapy in adult ADHD compared to clinical management in combination with psychopharmacological treatment or placebo. A total of 448 adults with ADHD according to DSM-IV will be treated at seven university sites in Germany. In a four-arm design, patients are randomized to a manualized dialectical behavioural therapy (DBT) based group programme plus methylphenidate or placebo or clinical management plus methylphenidate or placebo with weekly sessions in the first 12 weeks and monthly sessions thereafter. Therapists are graduated psychologists or physicians. Treatment integrity is established by independent supervision. Primary endpoint (ADHD symptoms measured by the Conners Adult Rating Scale) is rated by interviewers blind to the treatment allocation. Intention-to-treat analysis will be performed within a linear regression model (Current Controlled Trials ISRCTN54096201). The trial is funded by the German Federal Ministry of Research and Education (01GV0606) and is part of the German network for the treatment of ADHD in children and adults (ADHD-NET).

  20. Random tensors

    CERN Document Server

    Gurau, Razvan

    2017-01-01

    Written by the creator of the modern theory of random tensors, this book is the first self-contained introductory text to this rapidly developing theory. Starting from notions familiar to the average researcher or PhD student in mathematical or theoretical physics, the book presents in detail the theory and its applications to physics. The recent detections of the Higgs boson at the LHC and gravitational waves at LIGO mark new milestones in Physics confirming long standing predictions of Quantum Field Theory and General Relativity. These two experimental results only reinforce today the need to find an underlying common framework of the two: the elusive theory of Quantum Gravity. Over the past thirty years, several alternatives have been proposed as theories of Quantum Gravity, chief among them String Theory. While these theories are yet to be tested experimentally, key lessons have already been learned. Whatever the theory of Quantum Gravity may be, it must incorporate random geometry in one form or another....

  1. Random functions and turbulence

    CERN Document Server

    Panchev, S

    1971-01-01

    International Series of Monographs in Natural Philosophy, Volume 32: Random Functions and Turbulence focuses on the use of random functions as mathematical methods. The manuscript first offers information on the elements of the theory of random functions. Topics include determination of statistical moments by characteristic functions; functional transformations of random variables; multidimensional random variables with spherical symmetry; and random variables and distribution functions. The book then discusses random processes and random fields, including stationarity and ergodicity of random

  2. Construction and test of the PRIOR proton microscope; Aufbau und Test des Protonenmikroskops PRIOR

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Philipp-Michael

    2015-01-15

    The study of High Energy Density Matter (HEDM) in the laboratory makes great demands on the diagnostics because these states can usually only be created for a short time and usual diagnostic techniques with visible light or X-rays come to their limit because of the high density. The high energy proton radiography technique that was developed in the 1990s at the Los Alamos National Laboratory is a very promising possibility to overcome those limits so that one can measure the density of HEDM with high spatial and time resolution. For this purpose the proton microscope PRIOR (Proton Radiography for FAIR) was set up at GSI, which not only reproduces the image, but also magnifies it by a factor of 4.2 and thereby penetrates matter with a density up to 20 g/cm{sup 2}. Straightaway a spatial resolution of less than 30 μm and a time resolution on the nanosecond scale was achieved. This work describes details to the principle, design and construction of the proton microscope as well as first measurements and simulations of essential components like magnetic lenses, a collimator and a scintillator screen. For the latter one it was possible to show that plastic scintillators can be used as converter as an alternative to the slower but more radiation resistant crystals, so that it is possible to reach a time resolution of 10 ns. Moreover the characteristics were investigated for the system at the commissioning in April 2014. Also the changes in the magnetic field due to radiation damage were studied. Besides that an overview about future applications is given. First experiments with Warm Dense Matter created by using a Pulsed Power Setup have already been performed. Furthermore the promising concept of combining proton radiography with particle therapy has been investigated in context of the PaNTERA project. An outlook on the possibilities with future experiments at the FAIR accelerator facility is given as well. Because of higher beam intensity an energy one can expect even

  3. The excess mortality of patients with diabetes and concurrent psychiatric illness is markedly reduced by structured personal diabetes care. A 19-year follow up of the randomized controlled study Diabetes Care in General Practice (DCGP)

    DEFF Research Database (Denmark)

    Larsen, Julie Rask; Siersma, Volkert Dirk; Davidsen, Annette Sofie

    2016-01-01

    OBJECTIVE: To assess the effectiveness of an intervention in Type 2 diabetic patients with concurrent psychiatric illness (PI) and compare this with the effectiveness in patients without PI. METHOD: In the Diabetes Care in General Practice trial, 1381 patients newly diagnosed with Type 2 diabetes...... were randomized to 6 years of structured personal diabetes care or routine diabetes care (ClinicalTrials.gov NCT01074762). In this observational post-hoc analysis, the effectiveness of the intervention for diabetes in 179 patients with concurrent PI was analyzed. RESULTS: During the 19-year follow......-up period, patients with PI in the structured personal care group experienced a lower risk for all-cause mortality [105.3 vs. 140.4 events per 1000 patient-years; hazard ratio (HR): 0.63, P=0.023, multivariably adjusted], diabetes-related death (66.0 vs. 95.1; HR: 0.57, P=0.015), any diabetes...

  4. 34 CFR 300.220 - Exception for prior local plans.

    Science.gov (United States)

    2010-07-01

    ... CHILDREN WITH DISABILITIES Local Educational Agency Eligibility § 300.220 Exception for prior local plans... 34 Education 2 2010-07-01 2010-07-01 false Exception for prior local plans. 300.220 Section 300... effective date of the Individuals with Disabilities Education Improvement Act of 2004, the applicable...

  5. EEG Sequence Imaging: A Markov Prior for the Variational Garrote

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Hansen, Lars Kai

    2013-01-01

    We propose the following generalization of the Variational Garrote for sequential EEG imaging: A Markov prior to promote sparse, but temporally smooth source dynamics. We derive a set of modied Variational Garrote updates and analyze the role of the prior's hyperparameters. An experimental...

  6. Drunkorexia: Calorie Restriction Prior to Alcohol Consumption among College Freshman

    Science.gov (United States)

    Burke, Sloane C.; Cremeens, Jennifer; Vail-Smith, Karen; Woolsey, Conrad

    2010-01-01

    Using a sample of 692 freshmen at a southeastern university, this study examined caloric restriction among students prior to planned alcohol consumption. Participants were surveyed for self-reported alcohol consumption, binge drinking, and caloric intake habits prior to drinking episodes. Results indicated that 99 of 695 (14%) of first year…

  7. On the use of a pruning prior for neural networks

    DEFF Research Database (Denmark)

    Goutte, Cyril

    1996-01-01

    We address the problem of using a regularization prior that prunes unnecessary weights in a neural network architecture. This prior provides a convenient alternative to traditional weight-decay. Two examples are studied to support this method and illustrate its use. First we use the sunspots...

  8. 32 CFR 644.117 - Procedure prior to trial.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Procedure prior to trial. 644.117 Section 644.117... ESTATE HANDBOOK Acquisition Acquisition by Condemnation Proceedings § 644.117 Procedure prior to trial... United States Attorneys in negotiating settlements, preparing cases for trial, and in conducting such...

  9. On the Choice of Prior in Bayesian Model Averaging

    NARCIS (Netherlands)

    Einmahl, J.H.J.; Magnus, J.R.; Kumar, K.

    2011-01-01

    Bayesian model averaging attempts to combine parameter estimation and model uncertainty in one coherent framework. The choice of prior is then critical. Within an explicit framework of ignorance we define a ‘suitable’ prior as one which leads to a continuous and suitable analog to the pretest

  10. Personality, depressive symptoms and prior trauma exposure of new ...

    African Journals Online (AJOL)

    Background. Police officers are predisposed to trauma exposure. The development of depression and post-traumatic stress disorder (PTSD) may be influenced by personality style, prior exposure to traumatic events and prior depression. Objectives. To describe the personality profiles of new Metropolitan Police Service ...

  11. 9 CFR 309.12 - Emergency slaughter; inspection prior to.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Emergency slaughter; inspection prior... AND VOLUNTARY INSPECTION AND CERTIFICATION ANTE-MORTEM INSPECTION § 309.12 Emergency slaughter; inspection prior to. In all cases of emergency slaughter, except as provided in § 311.27 of this subchapter...

  12. Generalization of prior information for rapid Bayesian time estimation.

    Science.gov (United States)

    Roach, Neil W; McGraw, Paul V; Whitaker, David J; Heron, James

    2017-01-10

    To enable effective interaction with the environment, the brain combines noisy sensory information with expectations based on prior experience. There is ample evidence showing that humans can learn statistical regularities in sensory input and exploit this knowledge to improve perceptual decisions and actions. However, fundamental questions remain regarding how priors are learned and how they generalize to different sensory and behavioral contexts. In principle, maintaining a large set of highly specific priors may be inefficient and restrict the speed at which expectations can be formed and updated in response to changes in the environment. However, priors formed by generalizing across varying contexts may not be accurate. Here, we exploit rapidly induced contextual biases in duration reproduction to reveal how these competing demands are resolved during the early stages of prior acquisition. We show that observers initially form a single prior by generalizing across duration distributions coupled with distinct sensory signals. In contrast, they form multiple priors if distributions are coupled with distinct motor outputs. Together, our findings suggest that rapid prior acquisition is facilitated by generalization across experiences of different sensory inputs but organized according to how that sensory information is acted on.

  13. 34 CFR 303.403 - Prior notice; native language.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Prior notice; native language. 303.403 Section 303.403... TODDLERS WITH DISABILITIES Procedural Safeguards General § 303.403 Prior notice; native language. (a... file a complaint and the timelines under those procedures. (c) Native language. (1) The notice must be...

  14. Designing conjoint choice experiments using managers' prior beliefs

    NARCIS (Netherlands)

    Sandor, Z; Wedel, M

    2001-01-01

    The authors provide more efficient designs for conjoint choice experiments based on prior information elicited from managers about the parameters and their associated uncertainty. The authors use a Bayesian design procedure that assumes a prior distribution of likely parameter values and optimizes

  15. 5 CFR 3401.104 - Prior approval for outside employment.

    Science.gov (United States)

    2010-01-01

    ... engaging in outside employment with any person who is a “prohibited source” as that term is defined at 5... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Prior approval for outside employment... approval for outside employment. (a) Prior approval requirement. An employee, other than a special...

  16. The Effect of Prior Caffeine Consumption on Neuropsychological Test Performance: A Placebo-Controlled Study.

    Science.gov (United States)

    Walters, Elizabeth R; Lesk, Valerie E

    2016-01-01

    The aim of this study was to investigate whether the prior consumption of 200 mg of pure caffeine affected neuropsychological test scores in a group of elderly participants aged over 60 years. Using a double-blind placebo versus caffeine design, participants were randomly assigned to receive 200 mg of caffeine or placebo. A neuropsychological assessment testing the domains of general cognitive function, processing speed, semantic memory, episodic memory, executive function, working memory and short-term memory was carried out. Significant interaction effects between age, caffeine and scores of executive function and processing speed were found; participants who had received caffeine showed a decline in performance with increasing age. This effect was not seen for participants who received placebo. The results highlight the need to consider and control prior caffeine consumption when scoring neuropsychological assessments in the elderly, which is important for accuracy of diagnosis and corresponding normative data. © 2016 S. Karger AG, Basel.

  17. Markov random fields on triangle meshes

    DEFF Research Database (Denmark)

    Andersen, Vedrana; Aanæs, Henrik; Bærentzen, Jakob Andreas

    2010-01-01

    In this paper we propose a novel anisotropic smoothing scheme based on Markov Random Fields (MRF). Our scheme is formulated as two coupled processes. A vertex process is used to smooth the mesh by displacing the vertices according to a MRF smoothness prior, while an independent edge process label...

  18. Markov Random Fields on Triangle Meshes

    DEFF Research Database (Denmark)

    Andersen, Vedrana; Aanæs, Henrik; Bærentzen, Jakob Andreas

    2010-01-01

    In this paper we propose a novel anisotropic smoothing scheme based on Markov Random Fields (MRF). Our scheme is formulated as two coupled processes. A vertex process is used to smooth the mesh by displacing the vertices according to a MRF smoothness prior, while an independent edge process label...

  19. Determining the effective sample size of a parametric prior.

    Science.gov (United States)

    Morita, Satoshi; Thall, Peter F; Müller, Peter

    2008-06-01

    We present a definition for the effective sample size of a parametric prior distribution in a Bayesian model, and propose methods for computing the effective sample size in a variety of settings. Our approach first constructs a prior chosen to be vague in a suitable sense, and updates this prior to obtain a sequence of posteriors corresponding to each of a range of sample sizes. We then compute a distance between each posterior and the parametric prior, defined in terms of the curvature of the logarithm of each distribution, and the posterior minimizing the distance defines the effective sample size of the prior. For cases where the distance cannot be computed analytically, we provide a numerical approximation based on Monte Carlo simulation. We provide general guidelines for application, illustrate the method in several standard cases where the answer seems obvious, and then apply it to some nonstandard settings.

  20. Lighting-from-above prior in biological motion perception.

    Science.gov (United States)

    Fedorov, Leonid A; Dijkstra, Tjeerd M H; Giese, Martin A

    2018-01-24

    The visual system is able to recognize body motion from impoverished stimuli. This requires combining stimulus information with visual priors. We present a new visual illusion showing that one of these priors is the assumption that bodies are typically illuminated from above. A change of illumination direction from above to below flips the perceived locomotion direction of a biological motion stimulus. Control experiments show that the underlying mechanism is different from shape-from-shading and directly combines information about body motion with a lighting-from-above prior. We further show that the illusion is critically dependent on the intrinsic luminance gradients of the most mobile parts of the moving body. We present a neural model with physiologically plausible mechanisms that accounts for the illusion and shows how the illumination prior might be encoded within the visual pathway. Our experiments demonstrate, for the first time, a direct influence of illumination priors in high-level motion vision.

  1. Effects of an Updated Preventive Home Visit Program Based on a Systematic Structured Assessment of Care Needs for Ambulatory Frail Older Adults in Japan: A Randomized Controlled Trial.

    Science.gov (United States)

    Kono, Ayumi; Izumi, Kyoko; Yoshiyuki, Noriko; Kanaya, Yukiko; Rubenstein, Laurence Z

    2016-12-01

    The aim of this randomized controlled trial was to determine the effects on functional parameters of an updated preventive home visit program for frail older adults in the Japanese Long-term Care Insurance (LTCI) system. The program included home visits by nurses or care managers every 3 months for 24 months, with a systematic assessment of care needs to prevent functional decline. Eligible participants (N = 360) were randomly assigned to the visit (VG: n = 179) or control group (CG: n = 181). Functional parameters were gathered via mail questionnaires at baseline and at 12- and 24-month follow-ups. Care-need levels in the LTCI were obtained at 12-, 24-, and 36-month follow-ups and the utilization of the LTCI service through 36 months. Participants in VG were significantly more likely to maintain their activities of daily living (ADL) functioning (p = .0113) and less likely to increase care-needs level, compared with CG participants, over 24 months. A generalized linear model showed that the estimate of the effect on increase in care-needs level (ie, functional decline) was -0.53 (p = .042) over 36 months. These results suggest that the updated preventive home visit program could be effective for the prevention of ADL and care-needs deterioration, and these effects could continue up to 1 year after program completion. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. LCN: a random graph mixture model for community detection in functional brain networks.

    Science.gov (United States)

    Bryant, Christopher; Zhu, Hongtu; Ahn, Mihye; Ibrahim, Joseph

    2017-01-01

    The aim of this article is to develop a Bayesian random graph mixture model (RGMM) to detect the latent class network (LCN) structure of brain connectivity networks and estimate the parameters governing this structure. The use of conjugate priors for unknown parameters leads to efficient estimation, and a well-known nonidentifiability issue is avoided by a particular parameterization of the stochastic block model (SBM). Posterior computation proceeds via an efficient Markov Chain Monte Carlo algorithm. Simulations demonstrate that LCN outperforms several other competing methods for community detection in weighted networks, and we apply our RGMM to estimate the latent community structures in the functional resting brain networks of 185 subjects from the ADHD-200 sample. We find overlap in the estimated community structure across subjects, but also heterogeneity even within a given diagnosis group.

  3. Effects of a cognitive behavioral self-help program and a computerized structured writing intervention on depressed mood for HIV-infected people: a pilot randomized controlled trial

    NARCIS (Netherlands)

    Kraaij, V.; van Emmerik, A.; Garnefski, N.; Schroevers, M.J.; Lo-Fo-Wong, D.; Empelen, P.; Dusseldorp, E.; Witlox, R.; Maes, S.

    2010-01-01

    Objective: The aim of the present study was to examine whether low-resource, cost-effective intervention programs can be effective in improving depressed mood in people with HIV. The efficacy of a cognitive-behavioral self-help program (CBS) and a computerized structured writing intervention (SWI)

  4. Effects of a cognitive behavioral self-help program and a computerized structured writing intervention on depressed mood for HIV-infected people : A pilot randomized controlled trial

    NARCIS (Netherlands)

    Kraaij, Vivian; van Emmerik, Arnold; Garnefski, Nadia; Schroevers, Maya J.; Lo-Fo-Wong, Deborah; van Empelen, Pepijn; Dusseldorp, Elise; Witlox, Robert; Maes, Stan

    Objective: The aim of the present study was to examine whether low-resource, cost-effective intervention programs can be effective in improving depressed mood in people with HIV. The efficacy of a cognitive-behavioral self-help program (CBS) and a computerized structured writing intervention (SWI)

  5. Large Deviations for Random Trees.

    Science.gov (United States)

    Bakhtin, Yuri; Heitsch, Christine

    2008-08-01

    We consider large random trees under Gibbs distributions and prove a Large Deviation Principle (LDP) for the distribution of degrees of vertices of the tree. The LDP rate function is given explicitly. An immediate consequence is a Law of Large Numbers for the distribution of vertex degrees in a large random tree. Our motivation for this study comes from the analysis of RNA secondary structures.

  6. Prior weight loss exacerbates the biological drive to gain weight after the loss of ovarian function

    OpenAIRE

    Sherk, Vanessa D; Jackman, Matthew R.; Giles, Erin D.; Higgins, Janine A.; Foright, Rebecca M.; Presby, David M.; Johnson, Ginger C.; Houck, Julie A.; Houser, Jordan L.; Oljira, Robera; MacLean, Paul S.

    2017-01-01

    Abstract Both the history of obesity and weight loss may change how menopause affects metabolic health. The purpose was to determine whether obesity and/or weight loss status alters energy balance (EB) and subsequent weight gain after the loss of ovarian function. Female lean and obese Wistar rats were randomized to 15% weight loss (WL) or ad?libitum fed controls (CON). After the weight loss period, WL rats were kept in EB at the reduced weight for 8?weeks prior to ovariectomy (OVX). After OV...

  7. Successful management of severe refractory acquired immune bleeding disorder: Prior to insisting surgery

    Directory of Open Access Journals (Sweden)

    Hassan Al-Jafar

    2014-01-01

    CONCLUSION: This case of acquired bleeding disorder showed that more attention must be given to a patient's coagulation profile, even if only very minor laboratory coagulation derangements are detected prior to surgery, to avoid missing such rare disorders. The described triple therapy demonstrated good effects and may be considered for inclusion in a controlled randomized study to determine its usefulness for other surgeries delayed due to severe acquired bleeding disorders. To the best of our knowledge, this triple combination treatment has not been previously used for the treatment of severe acquired bleeding disorders that are refractory to conventional therapies.

  8. Semantic Labelling of Ultra Dense Mls Point Clouds in Urban Road Corridors Based on Fusing Crf with Shape Priors

    Science.gov (United States)

    Yao, W.; Polewski, P.; Krzystek, P.

    2017-09-01

    In this paper, a labelling method for the semantic analysis of ultra-high point density MLS data (up to 4000 points/m2) in urban road corridors is developed based on combining a conditional random field (CRF) for the context-based classification of 3D point clouds with shape priors. The CRF uses a Random Forest (RF) for generating the unary potentials of nodes and a variant of the contrastsensitive Potts model for the pair-wise potentials of node edges. The foundations of the classification are various geometric features derived by means of co-variance matrices and local accumulation map of spatial coordinates based on local neighbourhoods. Meanwhile, in order to cope with the ultra-high point density, a plane-based region growing method combined with a rule-based classifier is applied to first fix semantic labels for man-made objects. Once such kind of points that usually account for majority of entire data amount are pre-labeled; the CRF classifier can be solved by optimizing the discriminative probability for nodes within a subgraph structure excluded from pre-labeled nodes. The process can be viewed as an evidence fusion step inferring a degree of belief for point labelling from different sources. The MLS data used for this study were acquired by vehicle-borne Z+F phase-based laser scanner measurement, which permits the generation of a point cloud with an ultra-high sampling rate and accuracy. The test sites are parts of Munich City which is assumed to consist of seven object classes including impervious surfaces, tree, building roof/facade, low vegetation, vehicle and pole. The competitive classification performance can be explained by the diverse factors: e.g. the above ground height highlights the vertical dimension of houses, trees even cars, but also attributed to decision-level fusion of graph-based contextual classification approach with shape priors. The use of context-based classification methods mainly contributed to smoothing of labelling by removing

  9. Implicit Priors in Galaxy Cluster Mass and Scaling Relation Determinations

    Science.gov (United States)

    Mantz, A.; Allen, S. W.

    2011-01-01

    Deriving the total masses of galaxy clusters from observations of the intracluster medium (ICM) generally requires some prior information, in addition to the assumptions of hydrostatic equilibrium and spherical symmetry. Often, this information takes the form of particular parametrized functions used to describe the cluster gas density and temperature profiles. In this paper, we investigate the implicit priors on hydrostatic masses that result from this fully parametric approach, and the implications of such priors for scaling relations formed from those masses. We show that the application of such fully parametric models of the ICM naturally imposes a prior on the slopes of the derived scaling relations, favoring the self-similar model, and argue that this prior may be influential in practice. In contrast, this bias does not exist for techniques which adopt an explicit prior on the form of the mass profile but describe the ICM non-parametrically. Constraints on the slope of the cluster mass-temperature relation in the literature show a separation based the approach employed, with the results from fully parametric ICM modeling clustering nearer the self-similar value. Given that a primary goal of scaling relation analyses is to test the self-similar model, the application of methods subject to strong, implicit priors should be avoided. Alternative methods and best practices are discussed.

  10. The SHAZ! project: results from a pilot randomized trial of a structural intervention to prevent HIV among adolescent women in Zimbabwe.

    Directory of Open Access Journals (Sweden)

    Megan S Dunbar

    Full Text Available Adolescent females in Zimbabwe are at high risk for HIV acquisition. Shaping the Health of Adolescents in Zimbabwe (SHAZ! was a randomized controlled trial of a combined intervention package including life-skills and health education, vocational training, micro-grants and social supports compared to life-skills and health education alone. SHAZ! was originally envisioned as a larger effectiveness trial, however, the intervention was scaled back due to contextual and economic conditions in the country at the time. SHAZ! enrolled 315 participants randomly assigned to study arm within blocks of 50 participants (158 intervention and 157 control. The intervention arm participants showed statistically significant differences from the control arm participants for several outcomes during the two years of follow up including; reduced food insecurity [IOR = 0.83 vs. COR = 0.68, p-0.02], and having their own income [IOR = 2.05 vs. COR = 1.67, p = 0.02]. Additionally, within the Intervention arm there was a lower risk of transactional sex [IOR = 0.64, 95% CI (0.50, 0.83], and a higher likelihood of using a condom with their current partner [IOR = 1.79, 95% CI (1.23, 2.62] over time compared to baseline. There was also evidence of fewer unintended pregnancies among intervention participants [HR = 0.61, 95% CI (0.37, 1.01], although this relationship achieved only marginal statistical significance. Several important challenges in this study included the coordination with vocational training programs, the political and economic instability of the area at the time of the study, and the difficulty in creating a true standard of care control arm. Overall the results of the SHAZ! study suggest important potential for HIV prevention intervention packages that include vocational training and micro-grants, and lessons for further economic livelihoods interventions with adolescent females. Further work is needed to refine the

  11. Source-specific Informative Prior for i-Vector Extraction

    DEFF Research Database (Denmark)

    Shepstone, Sven Ewan; Lee, Kong Aik; Li, Haizhou

    2015-01-01

    An i-vector is a low-dimensional fixed-length representation of a variable-length speech utterance, and is defined as the posterior mean of a latent variable conditioned on the observed feature sequence of an utterance. The assumption is that the prior for the latent variable is non-informative......, since for homogeneous datasets there is no gain in generality in using an informative prior. This work shows that extracting i-vectors for a heterogeneous dataset, containing speech samples recorded from multiple sources, using informative priors instead is applicable, and leads to favorable results...

  12. Dependent generalized Dirichlet process priors for the analysis of acute lymphoblastic leukemia.

    Science.gov (United States)

    Barcella, William; De Iorio, Maria; Favaro, Stefano; Rosner, Gary L

    2017-09-06

    We propose a novel Bayesian nonparametric process prior for modeling a collection of random discrete distributions. This process is defined by including a suitable Beta regression framework within a generalized Dirichlet process to induce dependence among the discrete random distributions. This strategy allows for covariate dependent clustering of the observations. Some advantages of the proposed approach include wide applicability, ease of interpretation, and availability of efficient MCMC algorithms. The motivation for this work is the study of the impact of asparginage metabolism on lipid levels in a group of pediatric patients treated for acute lymphoblastic leukemia. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Correct performance of pelvic muscle exercises in women reporting prior knowledge.

    Science.gov (United States)

    Kandadai, Padma; O'Dell, Katharine; Saini, Jyot

    2015-01-01

    This study aimed to assess correct performance of pelvic muscle exercises (PMEs) in women presenting for urogynecologic care who express prior PME knowledge and to identify optimal instruction. New patients referred to urogynecology clinic reporting knowledge of PME or Kegels were asked to complete a questionnaire concerning knowledge, prior instruction, and current use of PME. During examination, the participants were asked to perform their PME or Kegel. Initial levator strength was documented by Oxford Scale. Randomized-order instructions were then given to educate women who contracted incorrectly. The participants completed a postexamination questionnaire. Analyses described percentage of women who were able to perform a correct contraction on initial attempt and factors associated with correct performance. Standard statistical methods were used to assess factors associated with correct PME performance and initial strength. Two hundred fifty eligible participants completed the questionnaires. Sixty (24%) participants were unable to correctly perform a PME initially. Of the 83 participants reporting current practice of PME, 23% performed them incorrectly. Prior instruction (odds ratio, 3.0; 95% confidence interval, 1.6-5.7; P < 0.01) and prior feedback (odds ratio, 3.5; 95% confidence interval, 1.0-12.0; P < 0.05) were associated with correct PME performance. In women who performed PME incorrectly at the initial assessment, "Squeeze the vaginal muscles you use to hold your urine" resulted in correct PME performance most often. Women reporting prior knowledge of PME may still perform them incorrectly. Providing instruction and feedback is strongly associated with correct performance and can be easily incorporated into pelvic examination. This may improve PME use and effectiveness to control symptoms of pelvic floor disorders.

  14. Binary pseudo-random patterned structures for modulation transfer function calibration and resolution characterization of a full-field transmission soft x-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Yashchuk, V. V., E-mail: VVYashchuk@lbl.gov; Chan, E. R.; Lacey, I. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fischer, P. J. [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California Santa Cruz, Santa Cruz, California 94056 (United States); Conley, R. [Advance Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States); McKinney, W. R. [Diablo Valley College, 321 Golf Club Road, Pleasant Hill, California 94523 (United States); Artemiev, N. A. [KLA-Tencor Corp., 1 Technology Drive, Milpitas, California 95035 (United States); Bouet, N. [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States); Cabrini, S. [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Calafiore, G.; Peroz, C.; Babin, S. [aBeam Technologies, Inc., Hayward, California 94541 (United States)

    2015-12-15

    We present a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) one-dimensional sequences and two-dimensional arrays as an effective method for spectral characterization in the spatial frequency domain of a broad variety of metrology instrumentation, including interferometric microscopes, scatterometers, phase shifting Fizeau interferometers, scanning and transmission electron microscopes, and at this time, x-ray microscopes. The inherent power spectral density of BPR gratings and arrays, which has a deterministic white-noise-like character, allows a direct determination of the MTF with a uniform sensitivity over the entire spatial frequency range and field of view of an instrument. We demonstrate the MTF calibration and resolution characterization over the full field of a transmission soft x-ray microscope using a BPR multilayer (ML) test sample with 2.8 nm fundamental layer thickness. We show that beyond providing a direct measurement of the microscope’s MTF, tests with the BPRML sample can be used to fine tune the instrument’s focal distance. Our results confirm the universality of the method that makes it applicable to a large variety of metrology instrumentation with spatial wavelength bandwidths from a few nanometers to hundreds of millimeters.

  15. Guanfacine extended release for children and adolescents with attention-deficit/hyperactivity disorder: efficacy following prior methylphenidate treatment.

    Science.gov (United States)

    Huss, Michael; Sikirica, Vanja; Hervas, Amaia; Newcorn, Jeffrey H; Harpin, Valerie; Robertson, Brigitte

    2016-01-01

    Guanfacine extended release (GXR) and atomoxetine (ATX) are nonstimulant treatments for attention-deficit/hyperactivity disorder (ADHD). As nonstimulant treatments are often used after stimulants in ADHD, GXR was assessed relative to prior stimulant treatment in a randomized controlled trial (RCT), in which ATX was included as a reference arm, and in the open-label phase of a randomized-withdrawal study (RWS). Participants were 6-17 years old with ADHD Rating Scale version IV (ADHD-RS-IV) scores ≥32 and Clinical Global Impressions - Severity scores ≥4. RCT participants received dose-optimized GXR (1-7 mg/day), ATX (10-100 mg/day), or placebo for 10-13 weeks. RWS participants received dose-optimized GXR (1-7 mg/day) for 13 weeks. Participants' last stimulant medication prior to enrolment, and reasons for stopping this medication, were collected at baseline. Change from baseline ADHD-RS-IV score and the proportion of responders were assessed by prior stimulant exposure. Of 163 RCT and 296 RWS participants who had previously received stimulant treatment, 142 and 224, respectively, had received methylphenidate (MPH); due to the low number of participants and the heterogeneity of non-MPH treatments, we only report data for prior MPH treatment. The most frequent reasons for stopping MPH were lack of effectiveness or side effects. Placebo-adjusted ADHD-RS-IV changes from baseline were significant in participants receiving GXR (prior MPH, -9.8, Peffect size [ES] 0.85; stimulant-naïve, -7.6, P0.05, ES 0.15) participants. More participants met responder criteria with GXR versus placebo, regardless of prior treatment. GXR response was unaffected by prior stimulant treatment; ATX produced improvement only in stimulant-naïve participants relative to placebo. These findings may be relevant to clinical decision-making regarding sequencing of ADHD treatments.

  16. Random fixed points and random differential inclusions

    Directory of Open Access Journals (Sweden)

    Nikolaos S. Papageorgiou

    1988-01-01

    Full Text Available In this paper, first, we study random best approximations to random sets, using fixed point techniques, obtaining this way stochastic analogues of earlier deterministic results by Browder-Petryshyn, KyFan and Reich. Then we prove two fixed point theorems for random multifunctions with stochastic domain that satisfy certain tangential conditions. Finally we consider a random differential inclusion with upper semicontinuous orientor field and establish the existence of random solutions.

  17. Reducing complexity of inverse problems using geostatistical priors

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Cordua, Knud Skou

    In a probabilistic formulation of inverse problems the solution can be given as a sample of the posterior probability distribution. All realizations retained in the posterior sample are consistent with both an assumed prior model and observed data. Some inverse problems are unsolvable, in that one...... can practically never hope to generate a posterior sample, others are just ’difficult’ and require special methods to become tractable, while others again are easily solved. We discuss how difficult nonlinear inverse problems can be handled such that their complexity, i.e. the time taken to obtain...... a posterior sample, can be reduced significantly using informed priors based on geostatistical models. We discuss two approaches to include such geostatistically based prior information. One is based on a parametric description of the prior likelihood that applies to 2-point based statistical models...

  18. 14 CFR 212.9 - Prior authorization requirements.

    Science.gov (United States)

    2010-01-01

    ... PROCEEDINGS) ECONOMIC REGULATIONS CHARTER RULES FOR U.S. AND FOREIGN DIRECT AIR CARRIERS § 212.9 Prior... operating rights of U.S. air carriers, or engaged in unfair, discriminatory, or restrictive practices with...

  19. Effect of prior information on noisy Bayesian frequency estimation

    Science.gov (United States)

    Li, Jun-Gang; Wang, Yuan-Mei; Yang, Di; Zou, Jian

    2017-11-01

    Quantum frequency estimation under general noise is investigated in the Bayesian parameter estimation approach. To evaluate the accuracy of estimation, the Bayes cost is obtained analytically which can be applied to the common noisy channels, such as the phase-damping channel, the amplitude-damping channel, and the depolarizing channel. The Bayes cost formula clearly shows that the prior information imposes a restriction upon the effect of noise in the estimation process. Three examples of frequency estimations are provided to illustrate the roles of prior probability in the estimation process. It is found that, due to the restriction of prior information on the noise, the estimation accuracy is less sensitive to the noise in the Bayesian approach than that in the Cramér-Rao bound approach. More prior information can help us to use the non-Gaussianity of the noise channel to improve the estimation accuracy in the phase-damping channel.

  20. Development Of Implicit Leadership Theories Prior To Training Or Employment

    National Research Council Canada - National Science Library

    Dean E. Frost

    2016-01-01

      This empirical study explored the development of implicit leadership theories among 16 to 18 year-old students in secondary schools prior to any formal leadership training or full-time employment...

  1. Assessment of prior learning in vocational education and training

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    The article deals about the results of a study of the assessment of prior learning among adult workers who want to obtain formal qualifications as skilled workers. The study contributes to developing methods for assessing prior learning including both the teachers’ ways of eliciting the students......’ knowledge, skills and competences during the students’ performances and the methods that the teachers apply in order to assess the students’ prior learning in relation to the regulations of the current VET-program. In particular the study focuses on how to assess not only the students’ explicated knowledge...... and skills but also their competences, i.e. the way the students use their skills and knowledge to perform in practice. Based on a description of the assessment procedures the article discusses central issues in relation to the assessment of prior learning. The empirical data have been obtained in the VET...

  2. Accuracy of different imaging modalities prior to biventricular repair ...

    African Journals Online (AJOL)

    invasive tests in patients with Tetralogy of Fallot prior to biventricular repair, and the need of invasive angiocardiography in specific subgroups. A retrospective analysis was performed for paediatric patients with Tetralogy of Fallot who underwent ...

  3. What good are actions? Accelerating learning using learned action priors

    CSIR Research Space (South Africa)

    Rosman, Benjamin S

    2012-11-01

    Full Text Available The computational complexity of learning in sequential decision problems grows exponentially with the number of actions available to the agent at each state. We present a method for accelerating this process by learning action priors that express...

  4. Rapid improvement of glycemic control in type 2 diabetes using weekly intensive multifactorial interventions: structured glucose monitoring, patient education, and adjustment of therapy-a randomized controlled trial.

    Science.gov (United States)

    Pimazoni-Netto, Augusto; Rodbard, David; Zanella, Maria Teresa

    2011-10-01

    We evaluated intensive intervention in poorly controlled patients with type 2 diabetes mellitus involving weekly clinic visits and adjustment of therapy with analysis of three seven-point glucose profiles and intervention from an interdisciplinary staff. Sixty-three patients were randomized to an intensive treatment group that obtained self-monitoring of blood glucose (SMBG) profiles (six or seven values per day, 3 days/week) and were seen in the clinic at Weeks 1-6 and 12. SMBG results were downloaded, analyzed using Accu-Chek(®) 360° software (Roche Diagnostics, Indianapolis, IN), and used to adjust therapy. Control group subjects obtained glucose profiles and had clinic visits only at Weeks 0, 6, and 12. There were highly statistically significant improvements in the intensive treatment group compared with the control group between Weeks 0 and 6 with greater reductions in weekly mean glycemia (WMG) (-76.7±8.9 mg/dL vs. -20.5±8.1 mg/dL), glycemic variability (SD) (-16.3±3.1 mg/dL vs. -5.0±3.1 mg/dL), and glycated hemoglobin (-1.82±0.16% vs. -0.66±0.22%) without significant changes in frequency of hypoglycemia or weight. Improvements were sustained in the intensive treatment group through Week 12. A minimal but statistically significant degree of improvement was seen in the control group at Week 12. This short-term pilot study of an intensive monitoring, educational, and pharmacological interventions program resulted in dramatic improvement of glycemic control within 6 weeks, and these effects are sustained through Week 12. SMBG glucose profiles, calculation of WMG and SD, and graphical displays of glucose data can improve the effectiveness of adjustment of therapy at weekly clinic visits when combined with intensive support from a multidisciplinary team.

  5. Structured cues or modafinil for fatigue amelioration in clinicians? A double-blind, randomized controlled trial of critical clinical information recall in fatigued clinicians.

    Science.gov (United States)

    Flindall, Ian; Leff, Daniel Richard; Goodship, Jonathan; Sugden, Colin; Darzi, Ara

    2016-04-01

    To evaluate the impact of modafinil on "free" and "cued" recall of clinical information in fatigued but nonsleep-deprived clinicians. Despite attempts to minimize sleep deprivation through redesign of the roster of residents and staff surgeons, evidence suggests that fatigue remains prevalent. The wake-promoting agent modafinil improves cognition in the sleep-deprived fatigued state and may improve information recall in fatigued nonsleep-deprived clinicians. Twenty-four medical undergraduates participated in a double-blind, parallel, randomized controlled trial (modafinil-200 mg:placebo). Medication was allocated 2 hours before a 90-minute fatigue-inducing, continuous performance task (dual 2-back task). A case history memorization task was then performed. Clinical information recall was assessed as "free"(no cognitive aids) and "cued"(using aid memoirs). Open and closed cues represent information of increasing specificity to aid the recall of clinical information. Fatigue was measured objectively using the psychomotor vigilance task at induction, before and after the dual 2-back task. Modafinil decreased false starts and lapses (modafinil = 0.50, placebo = 9.83, P modafinil = 0.006, placebo = 0.098, P Modafinil improved free information recall (modafinil = 137.8, placebo = 106.0, P modafinil = 62.3, placebo = 52.8, P = .1) and closed cues (modafinil = 80.1, placebo = 75.9, P = .3). Modafinil attenuated fatigue and improved free recall of clinical information without improving cue-based recall under the design of our experimental conditions. Memory cues to aid retrieval of clinical information are convenient interventions that could decrease fatigue-related error without adverse effects of the neuropharmacology. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Incorporating outcome uncertainty and prior outcome beliefs in stated preferences

    DEFF Research Database (Denmark)

    Lundhede, Thomas; Jacobsen, Jette Bredahl; Hanley, Nick

    2015-01-01

    ’ preferences for conservation policies under climate change, we find that higher outcome uncertainty reduces utility. When accounting for endogeneity, we find that prior beliefs play a significant role in this cost of uncertainty. Thus, merely stating “objective” levels of outcome uncertainty...... will not necessarily solve the problem of people valuing something differently from originally intended: respondents’ prior beliefs must be accounted for....

  7. Bayesian generalized linear mixed modeling of Tuberculosis using informative priors

    OpenAIRE

    Ojo, Oluwatobi Blessing; Lougue, Siaka; Woldegerima, Woldegebriel Assefa

    2017-01-01

    TB is rated as one of the world's deadliest diseases and South Africa ranks 9th out of the 22 countries with hardest hit of TB. Although many pieces of research have been carried out on this subject, this paper steps further by inculcating past knowledge into the model, using Bayesian approach with informative prior. Bayesian statistics approach is getting popular in data analyses. But, most applications of Bayesian inference technique are limited to situations of non-informative prior, where...

  8. Effective anxiety treatment prior to diagnostic cardiac catheterization.

    Science.gov (United States)

    McCaffrey, Ruth; Taylor, Natalie

    2005-01-01

    Music therapy, massage, guided imagery, therapeutic touch, and stress management instruction have been used successfully to decrease patient anxiety prior to diagnostic cardiac catheterization, providing better patient outcomes. The anxiety experienced among patients may have various causes, including not feeling cared about as an individual, too much waiting time before the procedure begins, and physical discomfort. This review determines nursing interventions that may effectively reduce anxiety prior to diagnostic cardiac catheterization.

  9. Emotions and a Prior Knowledge Representation in Artificial General Intelligence

    OpenAIRE

    Gavrilov, Andrey

    2008-01-01

    In this paper a prior knowledge representation for Artificial General Intelligence is proposed based on fuzzy rules using linguistic variables. These linguistic variables may be produced by neural network. Rules may be used for generation of basic emotions – positive and negative, which influence on planning and execution of behavior. The representation of Three Laws of Robotics as such prior knowledge is suggested as highest level of motivation in AGI.

  10. Preventing Ototoxic Synergy of Prior Noise Trauma During Aminoglycoside Therapy

    Science.gov (United States)

    2015-12-01

    Johns Hopkins University. 212 p (2007). 9. Liao S, et al. Noise Exposure in the Neonatal Intensive Care Unit : A Prospective Study. American Academy...AD_________________ Award Number: W81XWH-14-1-0006 TITLE: Preventing Ototoxic Synergy Of Prior Noise Trauma During Aminoglycoside Therapy ...Dec 2014 - 30 Nov 2015 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Preventing Ototoxic Synergy Of Prior Noise Trauma During Aminoglycoside Therapy

  11. SUSPENSION OF THE PRIOR DISCIPLINARY INVESTIGATION ACCORDING TO LABOR LAW

    Directory of Open Access Journals (Sweden)

    Nicolae, GRADINARU

    2014-11-01

    Full Text Available In order to conduct the prior disciplinary investigation, the employee shall be convoked in writing by the person authorized by the employer to carry out the research, specifying the subject, date, time and place of the meeting. For this purpose the employer shall appoint a committee charged with conducting the prior disciplinary investigation. Prior disciplinary research cannot be done without the possibility of the accused person to defend himself. It would be an abuse of the employer to violate these provisions. Since the employee is entitled to formulate and sustain defence in proving innocence or lesser degree of guilt than imputed, it needs between the moment were disclosed to the employee and the one of performing the prior disciplinary investigation to be a reasonable term for the employee to be able to prepare a defence in this regard. The employee's failure to present at the convocation, without an objective reason entitles the employer to dispose the sanctioning without making the prior disciplinary investigation. The objective reason which makes the employee, that is subject to prior disciplinary investigation, unable to present to the preliminary disciplinary investigation, should be at the time of the investigation in question.

  12. How Do Student Prior Achievement and Homework Behaviors Relate to Perceived Parental Involvement in Homework?

    OpenAIRE

    José C. Núñez; Epstein, Joyce L.; Natalia Suárez; Pedro Rosário; Guillermo Vallejo; Antonio Valle

    2017-01-01

    This study investigated how students’ prior achievement is related to their homework behaviors (i.e., time spent on homework, homework time management, and amount of homework), and to their perceptions of parental involvement in homework (i.e., parental control and parental support). A total of 1250 secondary students from 7 to 10th grade participated in the study. Structural equation models were fitted to the data, compared, and a partial mediation model was chosen. The results indicated tha...

  13. The relationship, structure and profiles of schizophrenia measurements: a post-hoc analysis of the baseline measures from a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Chen Lei

    2011-12-01

    Full Text Available Background To fully assess the various dimensions affected by schizophrenia, clinical trials often include multiple scales measuring various symptom profiles, cognition, quality of life, subjective well-being, and functional impairment. In this exploratory study, we characterized the relationships among six clinical, functional, cognitive, and quality-of-life measures, identifying a parsimonious set of measurements. Methods We used baseline data from a randomized, multicenter study of patients diagnosed with schizophrenia, schizoaffective disorder, or schizophreniform disorder who were experiencing an acute symptom exacerbation (n = 628 to examine the relationship among several outcome measures. These measures included the Positive and Negative Syndrome Scale (PANSS, Montgomery-Asberg Depression Rating Scale (MADRS, Brief Assessment of Cognition in Schizophrenia Symbol Coding Test, Subjective Well-being Under Neuroleptics Scale Short Form (SWN-K, Schizophrenia Objective Functioning Instrument (SOFI, and Quality of Life Scale (QLS. Three analytic approaches were used: 1 path analysis; 2 factor analysis; and 3 categorical latent variable analysis. In the optimal path model, the SWN-K was selected as the final outcome, while the SOFI mediated the effect of the exogenous variables (PANSS, MADRS on the QLS. Results The overall model explained 47% of variance in QLS and 17% of the variance in SOFI, but only 15% in SWN-K. Factor analysis suggested four factors: "Functioning," "Daily Living," "Depression," and "Psychopathology." A strong positive correlation was observed between the SOFI and QLS (r = 0.669, and both the QLS and SOFI loaded on the "Functioning" factor, suggesting redundancy between these scales. The measurement profiles from the categorical latent variable analysis showed significant variation in functioning and quality of life despite similar levels of psychopathology. Conclusions Researchers should consider collecting PANSS, SOFI, and

  14. Structural effects of sprifermin in knee osteoarthritis: a post-hoc analysis on cartilage and non-cartilaginous tissue alterations in a randomized controlled trial.

    Science.gov (United States)

    Roemer, Frank W; Aydemir, Aida; Lohmander, Stefan; Crema, Michel D; Marra, Monica Dias; Muurahainen, Norma; Felson, David T; Eckstein, Felix; Guermazi, Ali

    2016-07-09

    A recent publication on efficacy of Sprifermin for knee osteoarthritis (OA) using quantitatively MRI-defined central medial tibio-femoral compartment cartilage thickness as the structural primary endpoint reported no statistically significant dose response. However, Sprifermin was associated with statistically significant, dose-dependent reductions in loss of total and lateral tibio-femoral cartilage thickness. Based on these preliminary promising data a post-hoc analysis of secondary assessment and endpoints was performed to evaluate potential effects of Sprifermin on semi-quantitatively evaluated structural MRI parameters. Aim of the present analysis was to determine effects of sprifermin on several knee joint tissues over a 12 month period. 1.5 T or 3 T MRIs were acquired at baseline and 12 months follow-up using a standard protocol. MRIs were read according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) scoring system (in 14 articular subregions) by four muskuloskeletal radiologists independently. Analyses focused on semiquantitative changes in the 100 μg subgroup and matching placebo of multiple MRI-defined structural alterations. Analyses included a delta-subregional and delta-sum approach for the whole knee and the medial and lateral tibio-femoral (MTFJ, LTFJ), and patello-femoral (PFJ) compartments, taking into account number of subregions showing no change, improvement or worsening and changes in the sum of subregional scores. Mann-Whitney - Wilcoxon tests assessed differences between groups. Fifty-seven and 18 patients were included in the treatment and matched placebo subgroups. Less worsening of cartilage damage was observed from baseline to 12 months in the PFJ (0.02, 95 % confidence interval (CI) (-0.04, 0.08) vs. placebo 0.22, 95 % CI (-0.05, 0.49), p = 0.046). For bone marrow lesions (BMLs), more improvement was observed from 6 to 12 months for whole knee analyses (-0.14, 95 % CI (-0.48, 0.19) vs. placebo 0.44, 95

  15. Application of the artificial neural network for reconstructing the internal-structure image of a random medium by spatial characteristics of backscattered optical radiation

    Science.gov (United States)

    Veksler, B. A.; Meglinskii, I. V.

    2008-06-01

    The feasibility of using an artificial neural network (ANN), which is the standard Matlab tool, for non-invasive (based on the data of backscattering) diagnostics of macro-inhomogeneities, localised at subsurface layers of the turbid strongly scattering medium was shown. The spatial and angle distribution of the backscattered optical radiation was calculated by using the Monte-Carlo method combining the modelling of effective optical paths and the use of statistical weights. It was shown that application of the backscattering method together with the ANN allows solving inverse problems for determining the average radius of the scattering particles and for reconstructing the images of structural elements within the medium with a high accuracy.

  16. The Effect of a Non-Gaussian Random Loading on High-Cycle Fatigue of a Thermally Post-Buckled Structure

    Science.gov (United States)

    Rizzi, Stephen A.; Behnke, marlana N.; Przekop, Adam

    2010-01-01

    High-cycle fatigue of an elastic-plastic beam structure under the combined action of thermal and high-intensity non-Gaussian acoustic loadings is considered. Such loadings can be highly damaging when snap-through motion occurs between thermally post-buckled equilibria. The simulated non-Gaussian loadings investigated have a range of skewness and kurtosis typical of turbulent boundary layer pressure fluctuations in the vicinity of forward facing steps. Further, the duration and steadiness of high excursion peaks is comparable to that found in such turbulent boundary layer data. Response and fatigue life estimates are found to be insensitive to the loading distribution, with the minor exception of cases involving plastic deformation. In contrast, the fatigue life estimate was found to be highly affected by a different type of non-Gaussian loading having bursts of high excursion peaks.

  17. Malaria case management in Papua New Guinea prior to the introduction of a revised treatment protocol.

    Science.gov (United States)

    Pulford, Justin; Mueller, Ivo; Siba, Peter M; Hetzel, Manuel W

    2012-05-07

    This study aimed to document malaria case management practices in Papua New Guinea prior to the introduction of a revised national malaria treatment protocol. The revised protocol stipulates routine testing of malaria infection by rapid diagnostic test or microscopy, anti-malarial prescription to test positive cases only, and the introduction of a new artemisinin-based first-line anti-malarial. Findings presented in this paper primarily focus on diagnostic, prescription and treatment counselling practices. In a national cross-sectional survey of 79 randomly selected health facilities, data were collected via non-participant observation of the clinical case management of patients presenting with fever or a recent history of fever. Data were recorded on a structured clinical observation instrument. Overall, 15% of observed fever patients (n=468) were tested for malaria infection by rapid diagnostic test and a further 3.6% were tested via microscopy. An anti-malarial prescription was made in 96.4% (451/468) of cases, including 100% (17/17) of test positive cases and 82% (41/50) of test negative cases. In all, 79.8% of anti-malarial prescriptions conformed to the treatment protocol current at the time of data collection. The purpose of the prescribed medication was explained to patients in 63.4% of cases, dosage/regimen instructions were provided in 75.7% of cases and the possibility of adverse effects and what they might look like were discussed in only 1.1% of cases. The revised national malaria treatment protocol will require a substantial change in current clinical practice if it is to be correctly implemented and adhered to. Areas that will require the most change include the shift from presumptive to RDT/microscopy confirmed diagnosis, prescribing (or rather non-prescribing) of anti-malarials to patients who test negative for malaria infection, and the provision of thorough treatment counselling. A comprehensive clinician support programme, possibly inclusive of

  18. Eccentric exercise prior to hindlimb unloading attenuated reloading muscle damage in rats.

    Science.gov (United States)

    Prisby, Rhonda D; Nelson, Arnold G; Latsch, Elizabeth

    2004-11-01

    Antigravity muscles that are reloaded subsequent to hindlimb unloading (HU) are prone to injury. Similarities exist between muscle damage elicited from HU and subsequent reloading and damage induced by eccentric exercise (EE). Conditioning bouts of EE reduce muscle damage following a repeat bout of EE. Since damage to reloaded skeletal muscle is comparable to damage observed after EE, the mechanisms of damage are presumably similar. Therefore, EE prior to HU may attenuate reloading muscle damage. This study evaluated the effects of prior EE on rat soleus muscles (SOL) subsequent to 7 d of HU and 16-19 h of reloading. Sprague Dawley rats were randomly assigned to the following groups: eccentric exercise + hindlimb unloading + reloading (EEHUR; n = 9); hindlimb unloading + reloading (HUR; n = 10); eccentric exercise (EE; n = 12), or control (CON; n = 12). The exercise protocol was performed 5 d x wk(-1) for 2 wks followed by HU and reloading. Fiber areas were lower in both suspended groups vs. the EE and CON groups. There was no difference in percent interstitial area among groups. However, percent myofibrillar damage was higher in the HUR group vs. all other groups. Further, glucose-6-phospate dehydrogenase activity, an indicator of muscle damage, was higher in the HUR group compared with the EE and CON groups. These results provide some evidence that prior EE reduced muscle damage subsequent to HU and reloading. Therefore, EE may prove effective in minimizing recovery time in individuals suffering from muscle damage following periods of bed rest and spaceflight.

  19. Genetic characterisation of Malawian pneumococci prior to the roll-out of the PCV13 vaccine using a high-throughput whole genome sequencing approach.

    Directory of Open Access Journals (Sweden)

    Dean B Everett

    Full Text Available Malawi commenced the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13 into the routine infant immunisation schedule in November 2011. Here we have tested the utility of high throughput whole genome sequencing to provide a high-resolution view of pre-vaccine pneumococcal epidemiology and population evolutionary trends to predict potential future change in population structure post introduction.One hundred and twenty seven (127 archived pneumococcal isolates from randomly selected adults and children presenting to the Queen Elizabeth Central Hospital, Blantyre, Malawi underwent whole genome sequencing.The pneumococcal population was dominated by serotype 1 (20.5% of invasive isolates prior to vaccine introduction. PCV13 is likely to protect against 62.9% of all circulating invasive pneumococci (78.3% in under-5-year-olds. Several Pneumococcal Molecular Epidemiology Network (PMEN clones are now in circulation in Malawi which were previously undetected but the pandemic multidrug resistant PMEN1 lineage was not identified. Genome analysis identified a number of novel sequence types and serotype switching.High throughput genome sequencing is now feasible and has the capacity to simultaneously elucidate serotype, sequence type and as well as detailed genetic information. It enables population level characterization, providing a detailed picture of population structure and genome evolution relevant to disease control. Post-vaccine introduction surveillance supported by genome sequencing is essential to providing a comprehensive picture of the impact of PCV13 on pneumococcal population structure and informing future public health interventions.

  20. Prior-based artifact correction (PBAC) in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heußer, Thorsten, E-mail: thorsten.heusser@dkfz-heidelberg.de; Brehm, Marcus [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ritschl, Ludwig [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)

    2014-02-15

    Purpose: Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion. Methods: The proposed prior-based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image. Results: The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry-based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact-free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient-specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result. Conclusions: The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.

  1. Octonions in random matrix theory

    Science.gov (United States)

    Forrester, Peter J.

    2017-04-01

    The octonions are one of the four normed division algebras, together with the real, complex and quaternion number systems. The latter three hold a primary place in random matrix theory, where in applications to quantum physics they are determined as the entries of ensembles of Hermitian random matrices by symmetry considerations. Only for N=2 is there an existing analytic theory of Hermitian random matrices with octonion entries. We use a Jordan algebra viewpoint to provide an analytic theory for N=3. We then proceed to consider the matrix structure X†X, when X has random octonion entries. Analytic results are obtained from N=2, but are observed to break down in the 3×3 case.

  2. A new prior for bayesian anomaly detection: application to biosurveillance.

    Science.gov (United States)

    Shen, Y; Cooper, G F

    2010-01-01

    Bayesian anomaly detection computes posterior probabilities of anomalous events by combining prior beliefs and evidence from data. However, the specification of prior probabilities can be challenging. This paper describes a Bayesian prior in the context of disease outbreak detection. The goal is to provide a meaningful, easy-to-use prior that yields a posterior probability of an outbreak that performs at least as well as a standard frequentist approach. If this goal is achieved, the resulting posterior could be usefully incorporated into a decision analysis about how to act in light of a possible disease outbreak. This paper describes a Bayesian method for anomaly detection that combines learning from data with a semi-informative prior probability over patterns of anomalous events. A univariate version of the algorithm is presented here for ease of illustration of the essential ideas. The paper describes the algorithm in the context of disease-outbreak detection, but it is general and can be used in other anomaly detection applications. For this application, the semi-informative prior specifies that an increased count over baseline is expected for the variable being monitored, such as the number of respiratory chief complaints per day at a given emergency department. The semi-informative prior is derived based on the baseline prior, which is estimated from using historical data. The evaluation reported here used semi-synthetic data to evaluate the detection performance of the proposed Bayesian method and a control chart method, which is a standard frequentist algorithm that is closest to the Bayesian method in terms of the type of data it uses. The disease-outbreak detection performance of the Bayesian method was statistically significantly better than that of the control chart method when proper baseline periods were used to estimate the baseline behavior to avoid seasonal effects. When using longer baseline periods, the Bayesian method performed as well as the

  3. Light propagation in Swiss-cheese models of random close-packed Szekeres structures: Effects of anisotropy and comparisons with perturbative results

    Science.gov (United States)

    Koksbang, S. M.

    2017-03-01

    Light propagation in two Swiss-cheese models based on anisotropic Szekeres structures is studied and compared with light propagation in Swiss-cheese models based on the Szekeres models' underlying Lemaitre-Tolman-Bondi models. The study shows that the anisotropy of the Szekeres models has only a small effect on quantities such as redshift-distance relations, projected shear and expansion rate along individual light rays. The average angular diameter distance to the last scattering surface is computed for each model. Contrary to earlier studies, the results obtained here are (mostly) in agreement with perturbative results. In particular, a small negative shift, δ DA≔D/A-DA ,b g DA ,b g , in the angular diameter distance is obtained upon line-of-sight averaging in three of the four models. The results are, however, not statistically significant. In the fourth model, there is a small positive shift which has an especially small statistical significance. The line-of-sight averaged inverse magnification at z =1100 is consistent with 1 to a high level of confidence for all models, indicating that the area of the surface corresponding to z =1100 is close to that of the background.

  4. Improving novel motor learning through prior high contextual interference training

    NARCIS (Netherlands)

    Kim, T.; Chen, J.; Verwey, W. B.; Wright, David L.

    2018-01-01

    The primary objective of the present experiment was to examine the influence of recent practice in a random and blocked format for future motor learning. First, individuals practiced three unique discrete sequence production tasks in either a blocked or random schedule. One day later, all

  5. Assessment of Prior Learning in Adult Vocational Education and Training

    Directory of Open Access Journals (Sweden)

    Vibe Aarkrog

    2015-04-01

    Full Text Available The article deals about the results of a study of school-based Assessment of Prior Learning of adults who have enrolled as students in a VET college in order to qualify for occupations as skilled workers. Based on examples of VET teachers’ methods for assessing the students’ prior learning in the programs for gastronomes, respectively child care assistants the article discusses two issues in relation to Assessment of Prior Learing: the encounter of practical experience and school-based knowledge and the validity and reliability of the assessment procedures. Through focusing on the students’ knowing that and knowing why the assessment is based on a scholastic perception of the students’ needs for training, reflecting one of the most important challenges in Assessment of Prior Learning: how can practical experience be transformed into credits for the knowledge parts of the programs? The study shows that by combining several Assessment of Prior Learning methods and comparing the teachers’ assessments the teachers respond to the issues of validity and reliability. However, validity and reliability might be even further strengthened, if the competencies are well defined, if the education system is aware of securing a reasonable balance between knowing how, knowing that, and knowing why, and if the teachers are adequately trained for the assessment procedures.

  6. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging

    Directory of Open Access Journals (Sweden)

    Shuanghui Zhang

    2016-04-01

    Full Text Available This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP estimation and the maximum likelihood estimation (MLE are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  7. Incorporation of local dependent reliability information into the Prior Image Constrained Compressed Sensing (PICCS) reconstruction algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Vaegler, Sven; Sauer, Otto [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Stsepankou, Dzmitry; Hesser, Juergen [University Medical Center Mannheim, Mannheim (Germany). Dept. of Experimental Radiation Oncology

    2015-07-01

    The reduction of dose in cone beam computer tomography (CBCT) arises from the decrease of the tube current for each projection as well as from the reduction of the number of projections. In order to maintain good image quality, sophisticated image reconstruction techniques are required. The Prior Image Constrained Compressed Sensing (PICCS) incorporates prior images into the reconstruction algorithm and outperforms the widespread used Feldkamp-Davis-Kress-algorithm (FDK) when the number of projections is reduced. However, prior images that contain major variations are not appropriately considered so far in PICCS. We therefore propose the partial-PICCS (pPICCS) algorithm. This framework is a problem-specific extension of PICCS and enables the incorporation of the reliability of the prior images additionally. We assumed that the prior images are composed of areas with large and small deviations. Accordingly, a weighting matrix considered the assigned areas in the objective function. We applied our algorithm to the problem of image reconstruction from few views by simulations with a computer phantom as well as on clinical CBCT projections from a head-and-neck case. All prior images contained large local variations. The reconstructed images were compared to the reconstruction results by the FDK-algorithm, by Compressed Sensing (CS) and by PICCS. To show the gain of image quality we compared image details with the reference image and used quantitative metrics (root-mean-square error (RMSE), contrast-to-noise-ratio (CNR)). The pPICCS reconstruction framework yield images with substantially improved quality even when the number of projections was very small. The images contained less streaking, blurring and inaccurately reconstructed structures compared to the images reconstructed by FDK, CS and conventional PICCS. The increased image quality is also reflected in large RMSE differences. We proposed a modification of the original PICCS algorithm. The pPICCS algorithm

  8. Generating random networks and graphs

    CERN Document Server

    Coolen, Ton; Roberts, Ekaterina

    2017-01-01

    This book supports researchers who need to generate random networks, or who are interested in the theoretical study of random graphs. The coverage includes exponential random graphs (where the targeted probability of each network appearing in the ensemble is specified), growth algorithms (i.e. preferential attachment and the stub-joining configuration model), special constructions (e.g. geometric graphs and Watts Strogatz models) and graphs on structured spaces (e.g. multiplex networks). The presentation aims to be a complete starting point, including details of both theory and implementation, as well as discussions of the main strengths and weaknesses of each approach. It includes extensive references for readers wishing to go further. The material is carefully structured to be accessible to researchers from all disciplines while also containing rigorous mathematical analysis (largely based on the techniques of statistical mechanics) to support those wishing to further develop or implement the theory of rand...

  9. Development and evaluation of a structured programme for promoting physical activity among seniors with intellectual disabilities: a study protocol for a cluster randomized trial.

    Science.gov (United States)

    van Schijndel-Speet, Marieke; Evenhuis, Heleen M; van Empelen, Pepijn; van Wijck, Ruud; Echteld, Michael A

    2013-08-12

    Older people with intellectual disabilities have very low physical activity levels. Well designed, theory-driven and evidence-based health promotion programmes for the target population are lacking. This paper describes the design of a cluster-randomised trial for a systematically developed health promotion programme aimed at improving physical activity and increasing fitness among seniors with intellectual disabilities. The Intervention Mapping protocol was used for programme development. After defining the programme's objectives, the following behavioural techniques were selected to achieve them: Tailoring, Education, Modelling, Mirroring, Feedback, Reinforcement and Grading. With professionals and managers of provider services for people with intellectual disabilities, we translated these strategies into a structured day-activity programme, that consisted of a physical activity and an education programme. The programme will be executed in five day-activity centres in groups of eight to ten seniors during eight months, whereas seniors in five other centres receive care as usual. The physical activity level, as measured in number of steps a day, will be used as primary outcome measurement. Secondary outcome measurements include motor fitness, cardio respiratory fitness, morphological and metabolic fitness, ADL, functional deterioration and depressive symptoms. Differences in the primary and secondary outcome measures between participants and controls will be analysed using generalized estimation equations, correcting for day-activity center as cluster. This paper provides insight into the development and content of a theory-driven intervention aimed at behavioural change in a population with a low intellectual level. Its evaluation design is described. The programme's applicability to other populations is discussed.

  10. [Identification of the prior regions for agricultural and rural pollution control in Changshu].

    Science.gov (United States)

    Duan, Hua-ping; Sun, Qing-fang; Wang, Liang; Zhu, Lin; Feng, Jin-fei; Bian, Xin-min

    2010-04-01

    The characteristics such as wide area, dispersion and randomness of agricultural and rural pollution make it difficult to seize the key to pollution control in rural areas. On the scale of township, using inventory analysis, accounting for emissions and emission intensity of the chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in Changshu, Jiangsu Province, which exists in a total of 4 classes and 6 kinds of agricultural and rural sources such as farmland cultivation (chemical fertilizer application and crop straw abandoned), animal breeding, aquaculture, rural life (domestic sewage and human waste, solid waste), using cluster analysis, identify the prior regions and the prior pollution sources for agricultural and rural pollution control by the sensitivity evaluation, and make agricultural and rural pollution control and management measures more focused. It shows that: in 2007, COD, TN and TP emissions of agricultural and rural pollution sources were 5496.07, 4161.03, and 647.54 t x a(-1), and the emission intensity of COD, TN and TP was 48.84, 36.98, and 5.75 kg x hm(-2). The main pollution source of COD was rural life and aquaculture, and the contribution rate was more than 75%; the main pollution source of TN and TP was agricultural cultivation and aquaculture, and the contribution rate was more than 80%. The sensitivity evaluation identified that the town of Guli and Shajiabang were the prior regions for agricultural and rural pollution control in Changshu; farmland cultivation and aquaculture were the prior pollution sources in the two areas.

  11. Approximate Message Passing with Restricted Boltzmann Machine Priors

    CERN Document Server

    Tramel, Eric W; Krzakala, Florent

    2015-01-01

    Approximate Message Passing (AMP) has been shown to be an excellent statistical approach to signal inference and compressed sensing problem. The AMP framework provides modularity in the choice of signal prior; here we propose a hierarchical form of the Gauss-Bernouilli prior which utilizes a Restricted Boltzmann Machine (RBM) trained on the signal support to push reconstruction performance beyond that of simple iid priors for signals whose support can be well represented by a trained binary RBM. We present and analyze two methods of RBM factorization and demonstrate how these affect signal reconstruction performance within our proposed algorithm. Finally, using the MNIST handwritten digit dataset, we show experimentally that using an RBM allows AMP to approach oracle-support performance.

  12. Expected behavior of quantum thermodynamic machines with prior information.

    Science.gov (United States)

    Thomas, George; Johal, Ramandeep S

    2012-04-01

    We estimate the expected behavior of the quantum model of a heat engine when we have incomplete information about external macroscopic parameters such as the magnetic field controlling the intrinsic energy scales of the working medium. We explicitly derive the prior probability distribution for these unknown parameters ai (i=1,2). Based on a few simple assumptions, the prior probability distribution is found to be of the form Π(ai)∝1/ai. By calculating the expected values of various physical quantities related to this engine, we find that the expected behavior of the quantum model exhibits thermodynamiclike features. This leads us to a surprising proposal that incomplete information quantified as an appropriate prior distribution can lead us to expect classical thermodynamic behavior in quantum models.

  13. The dual frontier: Patented inventions and prior scientific advance.

    Science.gov (United States)

    Ahmadpoor, Mohammad; Jones, Benjamin F

    2017-08-11

    The extent to which scientific advances support marketplace inventions is largely unknown. We study 4.8 million U.S. patents and 32 million research articles to determine the minimum citation distance between patented inventions and prior scientific advances. We find that most cited research articles (80%) link forward to a future patent. Similarly, most patents (61%) link backward to a prior research article. Linked papers and patents typically stand 2 to 4 degrees distant from the other domain. Yet, advances directly along the patent-paper boundary are notably more impactful within their own domains. The distance metric further provides a typology of the fields, institutions, and individuals involved in science-to-technology linkages. Overall, the findings are consistent with theories that emphasize substantial and fruitful connections between patenting and prior scientific inquiry. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  14. Drug repurposing and the prior art patents of competitors.

    Science.gov (United States)

    Sternitzke, Christian

    2014-12-01

    Drug repurposing (i.e., finding novel indications for established substances) has received increasing attention in industry recently. One challenge of repositioned drugs is obtaining effective patent protection, especially if the 'novel' indications have already been claimed by competitors within the same drug class. Here, I report the case of patents relating to phosphodiesterase type 5 (PDE5) inhibitors. Patentees of later-filed patents on novel indications (even when they could not observe prior patenting of their direct competitors) filed patents for which patent examiners did not see the prior-filed patents of the competitors as relevant prior art, whereas these follower patent applications often failed because of other reasons. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Metal artifact reduction based on the combined prior image

    CERN Document Server

    Zhang, Yanbo

    2014-01-01

    Metallic implants introduce severe artifacts in CT images, which degrades the image quality. It is an effective method to reduce metal artifacts by replacing the metal affected projection with the forward projection of a prior image. How to find a good prior image is the key of this class methods, and numerous algorithms have been proposed to address this issue recently. In this work, by using image mutual correlation, pixels in the original reconstructed image or linear interpolation corrected image, which are less affected by artifacts, are selected to build a combined image. Thereafter, a better prior image is generated from the combined image by using tissue classification. The results of three patients' CT images show that the proposed method can reduce metal artifacts remarkably.

  16. Evaluating Prior Learning Assessment Programs: A Suggested Framework

    Directory of Open Access Journals (Sweden)

    Nan L. Travers and Marnie T. Evans

    2011-01-01

    Full Text Available Over the past two decades, American institutions have been expected to include systematic program reviews to meet accrediting standards, either by independent or governmental review agencies. Program evaluation is critical for several reasons: it provides systematic ways to assess what needs improvement or what needs changing and it provides ways to validate practices, whether to internal or external audiences (Mishra, 2007. Most program evaluative models are focused on academic programs, which don’t fit the uniqueness of prior learning assessment programs. This paper proposes an evaluative framework for prior learning assessment programs, which takes into account the type of work within prior learning assessment programs and uses program portfolios, similar to how students are asked to document their work.

  17. Effective Image Restorations Using a Novel Spatial Adaptive Prior

    Directory of Open Access Journals (Sweden)

    Limin Luo

    2010-01-01

    Full Text Available Bayesian or Maximum a posteriori (MAP approaches can effectively overcome the ill-posed problems of image restoration or deconvolution through incorporating a priori image information. Many restoration methods, such as nonquadratic prior Bayesian restoration and total variation regularization, have been proposed with edge-preserving and noise-removing properties. However, these methods are often inefficient in restoring continuous variation region and suppressing block artifacts. To handle this, this paper proposes a Bayesian restoration approach with a novel spatial adaptive (SA prior. Through selectively and adaptively incorporating the nonlocal image information into the SA prior model, the proposed method effectively suppress the negative disturbance from irrelevant neighbor pixels, and utilizes the positive regularization from the relevant ones. A two-step restoration algorithm for the proposed approach is also given. Comparative experimentation and analysis demonstrate that, bearing high-quality edge-preserving and noise-removing properties, the proposed restoration also has good deblocking property.

  18. Effective Image Restorations Using a Novel Spatial Adaptive Prior

    Directory of Open Access Journals (Sweden)

    Hao Liwei

    2010-01-01

    Full Text Available Abstract Bayesian or Maximum a posteriori (MAP approaches can effectively overcome the ill-posed problems of image restoration or deconvolution through incorporating a priori image information. Many restoration methods, such as nonquadratic prior Bayesian restoration and total variation regularization, have been proposed with edge-preserving and noise-removing properties. However, these methods are often inefficient in restoring continuous variation region and suppressing block artifacts. To handle this, this paper proposes a Bayesian restoration approach with a novel spatial adaptive (SA prior. Through selectively and adaptively incorporating the nonlocal image information into the SA prior model, the proposed method effectively suppress the negative disturbance from irrelevant neighbor pixels, and utilizes the positive regularization from the relevant ones. A two-step restoration algorithm for the proposed approach is also given. Comparative experimentation and analysis demonstrate that, bearing high-quality edge-preserving and noise-removing properties, the proposed restoration also has good deblocking property.

  19. New prior sampling methods for nested sampling - Development and testing

    Science.gov (United States)

    Stokes, Barrie; Tuyl, Frank; Hudson, Irene

    2017-06-01

    Nested Sampling is a powerful algorithm for fitting models to data in the Bayesian setting, introduced by Skilling [1]. The nested sampling algorithm proceeds by carrying out a series of compressive steps, involving successively nested iso-likelihood boundaries, starting with the full prior distribution of the problem parameters. The "central problem" of nested sampling is to draw at each step a sample from the prior distribution whose likelihood is greater than the current likelihood threshold, i.e., a sample falling inside the current likelihood-restricted region. For both flat and informative priors this ultimately requires uniform sampling restricted to the likelihood-restricted region. We present two new methods of carrying out this sampling step, and illustrate their use with the lighthouse problem [2], a bivariate likelihood used by Gregory [3] and a trivariate Gaussian mixture likelihood. All the algorithm development and testing reported here has been done with Mathematica® [4].

  20. Supersymmetry in Random Matrix Theory

    OpenAIRE

    Guhr, Thomas

    2010-01-01

    Supersymmetry is nowadays indispensable for many problems in Random Matrix Theory. It is presented here with an emphasis on conceptual and structural issues. An introduction to supermathematics is given. The Hubbard-Stratonovich transformation as well as its generalization and superbosonization are explained. The supersymmetric non-linear sigma model, Brownian motion in superspace and the color-flavor transformation are discussed.

  1. Fatigue Reliability under Random Loads

    DEFF Research Database (Denmark)

    Talreja, R.

    1979-01-01

    We consider the problem of estimating the probability of survival (non-failure) and the probability of safe operation (strength greater than a limiting value) of structures subjected to random loads. These probabilities are formulated in terms of the probability distributions of the loads and the...... propagation stage. The consequences of this behaviour on the fatigue reliability are discussed....

  2. Physical examination prior to initiating hormonal contraception: a systematic review.

    Science.gov (United States)

    Tepper, Naomi K; Curtis, Kathryn M; Steenland, Maria W; Marchbanks, Polly A

    2013-05-01

    Provision of contraception is often linked with physical examination, including clinical breast examination (CBE) and pelvic examination. This review was conducted to evaluate the evidence regarding outcomes among women with and without physical examination prior to initiating hormonal contraceptives. The PubMed database was searched from database inception through March 2012 for all peer-reviewed articles in any language concerning CBE and pelvic examination prior to initiating hormonal contraceptives. The quality of each study was assessed using the United States Preventive Services Task Force grading system. The search did not identify any evidence regarding outcomes among women screened versus not screened with CBE prior to initiation of hormonal contraceptives. The search identified two case-control studies of fair quality which compared women who did or did not undergo pelvic examination prior to initiating oral contraceptives (OCs) or depot medroxyprogesterone acetate (DMPA). No differences in risk factors for cervical neoplasia, incidence of sexually transmitted infections, incidence of abnormal Pap smears or incidence of abnormal wet mount findings were observed. Although women with breast cancer should not use hormonal contraceptives, there is little utility in screening prior to initiation, due to the low incidence of breast cancer and uncertain value of CBE among women of reproductive age. Two fair quality studies demonstrated no differences between women who did or did not undergo pelvic examination prior to initiating OCs or DMPA with respect to risk factors or clinical outcomes. In addition, pelvic examination is not likely to detect any conditions for which hormonal contraceptives would be unsafe. Published by Elsevier Inc.

  3. Phase transitions in restricted Boltzmann machines with generic priors

    Science.gov (United States)

    Barra, Adriano; Genovese, Giuseppe; Sollich, Peter; Tantari, Daniele

    2017-10-01

    We study generalized restricted Boltzmann machines with generic priors for units and weights, interpolating between Boolean and Gaussian variables. We present a complete analysis of the replica symmetric phase diagram of these systems, which can be regarded as generalized Hopfield models. We underline the role of the retrieval phase for both inference and learning processes and we show that retrieval is robust for a large class of weight and unit priors, beyond the standard Hopfield scenario. Furthermore, we show how the paramagnetic phase boundary is directly related to the optimal size of the training set necessary for good generalization in a teacher-student scenario of unsupervised learning.

  4. Total Variability Modeling using Source-specific Priors

    DEFF Research Database (Denmark)

    Shepstone, Sven Ewan; Lee, Kong Aik; Li, Haizhou

    2016-01-01

    , can lead to favorable results. We focus on modeling the priors using minimum divergence criterion or fac- tor analysis techniques. Tests on the NIST 2008 and 2010 Speaker Recognition Evaluation (SRE) dataset show that our proposed method beats four baselines: For i-vector extraction using an already...... trained matrix, for the short2-short3 task in SRE’08, five out of eight female and four out of eight male common conditions, were improved. For the core-extended task in SRE’10, four out of nine female and six out of nine male common conditions were improved. When incorporating prior information...

  5. Idarucizumab for Reversal of Dabigatran Prior to Acute Surgery

    DEFF Research Database (Denmark)

    Rosenberg, Lene; Gerstrøm, Gustav; Nybo, Mads

    2017-01-01

    and acetylsalicylic acid. In this case, the decision to use idarucizumab was based on the clinical manifestations and other routine coagulation parameters, as the plasma dabigatran concentration was not available prior to administration. Due to challenges with the plasma dabigatran analysis and taking the safety...... in case of life-threatening bleeding or acute surgery/invasive procedures. Whether usage should be guided by measurement of plasma dabigatran and/or other coagulation parameters is, however, still uncertain. We here describe the use of idarucizumab prior to acute surgery in a patient on dabigatran...

  6. C. A. Meredith, A. N. Prior, and Possible Worlds

    DEFF Research Database (Denmark)

    Hasle, Per Frederik Vilhelm; Rybaříková, Zuzana

    of Meredith’s and Prior’s work. On the one hand, it might cause corruption of Meredith’s system of logic and lead to paradoxes, as Prior pointed out in ‘Modal Logic with Functorial Variables and a Contingent Constant’. On the other hand, considering Prior as a mere follower of Meredith could cause......, their understanding of the relevant formal representations and indeed their general approach to modal logic considerably differed. These differences should be pointed out in order to more precisely appreciate the contribution of each of these authors. To neglect the differences could cause the misinterpretation...

  7. Challenges in relation to assessment of prior learning

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    2013-01-01

    unskilled workers’) prior learning, i.e. their work experiences and informal learning. In the paper we will describe and point to some challenges in relation to assessing the students’ prior learning. The assessment is accomplished by teachers and supervisors in VET colleges. The assessment includes 1......The paper deals about preliminary results from an on-going project: “From unskilled worker to skilled worker in record time”. The aim of the project is to qualify unskilled workers for skilled positions in record time by drafting up a plan for the training based on assessment of the students’ (the...

  8. Wolf's Isotopic Response: Varicella Within a Prior Immunization Reaction Site.

    Science.gov (United States)

    Wu, Sam; McShane, Diana B; Burkhart, Craig N; Morrell, Dean S

    2015-01-01

    Wolf's isotopic response describes the occurrence of a dermatologic condition at the site of a prior healed unrelated condition. Our report details a case of varicella occurring as a secondary condition at the site of a prior immunization reaction; herpesvirus infection has not been reported as a secondary condition in cases of Wolf's isotopic response before. Current hypotheses favor the involvement of neurohormonal modulation of local immunity in response to various forms of injury as a model for explaining these phenomena. © 2015 Wiley Periodicals, Inc.

  9. Browsing while reading: effects of instructional design and learners' prior knowledge

    Directory of Open Access Journals (Sweden)

    Theimo Müller-Kalthoff

    2006-12-01

    Full Text Available One of the key reasons that multimedia, and particularly hypertext systems, are gaining in importance is that they inspire hopes of optimizing learners' processes of knowledge construction. The present study is concerned with the respective influence of individual learner variables (i.e. particularly domain-specific prior knowledge on the use of different design attributes. Thirty-six university students worked through a hierarchically structured two-part hypertext about the psychology of memory under two experimental browsing conditions (reduced versus free browsing. Results show that deeper-level comprehension (i.e. structural knowledge was predicted by the interaction of experimental condition and prior knowledge, but that simply retaining facts was not. Participants with low prior knowledge performed better on the comprehension test if they had worked on the version with reduced access. Moreover, the version with reduced access helped to reduce feelings of disorientation. The measure of disorientation also appeared to be closely linked with the individual's computer experience, self-concept of computer ability and subject-related interest. The main implications for educational practice relate to the design of an adaptive multimedia and hypertext learning system and the successful learning with it.

  10. Flexible link functions in nonparametric binary regression with Gaussian process priors.

    Science.gov (United States)

    Li, Dan; Wang, Xia; Lin, Lizhen; Dey, Dipak K

    2016-09-01

    In many scientific fields, it is a common practice to collect a sequence of 0-1 binary responses from a subject across time, space, or a collection of covariates. Researchers are interested in finding out how the expected binary outcome is related to covariates, and aim at better prediction in the future 0-1 outcomes. Gaussian processes have been widely used to model nonlinear systems; in particular to model the latent structure in a binary regression model allowing nonlinear functional relationship between covariates and the expectation of binary outcomes. A critical issue in modeling binary response data is the appropriate choice of link functions. Commonly adopted link functions such as probit or logit links have fixed skewness and lack the flexibility to allow the data to determine the degree of the skewness. To address this limitation, we propose a flexible binary regression model which combines a generalized extreme value link function with a Gaussian process prior on the latent structure. Bayesian computation is employed in model estimation. Posterior consistency of the resulting posterior distribution is demonstrated. The flexibility and gains of the proposed model are illustrated through detailed simulation studies and two real data examples. Empirical results show that the proposed model outperforms a set of alternative models, which only have either a Gaussian process prior on the latent regression function or a Dirichlet prior on the link function. © 2015, The International Biometric Society.

  11. Fatigue durability under random cyclic loading

    Science.gov (United States)

    Volkov, S. S.; Struzhanov, V. V.

    2017-12-01

    Methods for predicting the durability of metals have been developed while taking into account the effect of random loads acting during the service life of structures. Methods of the theory of functions of random variables are applied. Normal distribution and the Rayleigh distribution are used to estimate the random loads from the experimental histogram. A numerical example illustrates the influence of the statistical parameters of the load distribution on the predicted number of cycles before failure.

  12. 3D microwave tomography of the breast using prior anatomical information

    Energy Technology Data Exchange (ETDEWEB)

    Golnabi, Amir H., E-mail: golnabia@montclair.edu [Department of Mathematical Sciences, Montclair State University, Montclair, New Jersey 07043 (United States); Meaney, Paul M. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Paulsen, Keith D. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Department of Radiology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755 (United States); Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756 (United States); Advanced Surgical Center, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756 (United States)

    2016-04-15

    Purpose: The authors have developed a new 3D breast image reconstruction technique that utilizes the soft tissue spatial resolution of magnetic resonance imaging (MRI) and integrates the dielectric property differentiation from microwave imaging to produce a dual modality approach with the goal of augmenting the specificity of MR imaging, possibly without the need for nonspecific contrast agents. The integration is performed through the application of a soft prior regularization which imports segmented geometric meshes generated from MR exams and uses it to constrain the microwave tomography algorithm to recover nearly uniform property distributions within segmented regions with sharp delineation between these internal subzones. Methods: Previous investigations have demonstrated that this approach is effective in 2D simulation and phantom experiments and also in clinical exams. The current study extends the algorithm to 3D and provides a thorough analysis of the sensitivity and robustness to misalignment errors in size and location between the spatial prior information and the actual data. Results: Image results in 3D were not strongly dependent on reconstruction mesh density, and the changes of less than 30% in recovered property values arose from variations of more than 125% in target region size—an outcome which was more robust than in 2D. Similarly, changes of less than 13% occurred in the 3D image results from variations in target location of nearly 90% of the inclusion size. Permittivity and conductivity errors were about 5 times and 2 times smaller, respectively, with the 3D spatial prior algorithm in actual phantom experiments than those which occurred without priors. Conclusions: The presented study confirms that the incorporation of structural information in the form of a soft constraint can considerably improve the accuracy of the property estimates in predefined regions of interest. These findings are encouraging and establish a strong foundation for

  13. Does physiotherapy based on the Bobath concept, in conjunction with a task practice, achieve greater improvement in walking ability in people with stroke compared to physiotherapy focused on structured task practice alone?: a pilot randomized controlled trial.

    Science.gov (United States)

    Brock, Kim; Haase, Gerlinde; Rothacher, Gerhard; Cotton, Susan

    2011-10-01

    To compare the short-term effects of two physiotherapy approaches for improving ability to walk in different environments following stroke: (i) interventions based on the Bobath concept, in conjunction with task practice, compared to (ii) structured task practice alone. Randomized controlled trial. Two rehabilitation centres Participants: Twenty-six participants between four and 20 weeks post-stroke, able to walk with supervision indoors. Both groups received six one-hour physiotherapy sessions over a two-week period. One group received physiotherapy based on the Bobath concept, including one hour of structured task practice. The other group received six hours of structured task practice. The primary outcome was an adapted six-minute walk test, incorporating a step, ramp and uneven surface. Secondary measures were gait velocity and the Berg Balance Scale. Measures were assessed before and after the intervention period. Following the intervention, there was no significant difference in improvement between the two groups for the adapted six-minute walk test (89.9 (standard deviation (SD) 73.1) m Bobath versus 41 (40.7) m task practice, P = 0.07). However, walking velocity showed significantly greater increases in the Bobath group (26.2 (SD 17.2) m/min versus 9.9 (SD = 12.9) m/min, P = 0.01). No significant differences between groups were recorded for the Berg Balance Scale (P = 0.2). This pilot study indicates short-term benefit for using interventions based on the Bobath concept for improving walking velocity in people with stroke. A sample size of 32 participants per group is required for a definitive study.

  14. Priors in whole-genome regression: the bayesian alphabet returns.

    Science.gov (United States)

    Gianola, Daniel

    2013-07-01

    Whole-genome enabled prediction of complex traits has received enormous attention in animal and plant breeding and is making inroads into human and even Drosophila genetics. The term "Bayesian alphabet" denotes a growing number of letters of the alphabet used to denote various Bayesian linear regressions that differ in the priors adopted, while sharing the same sampling model. We explore the role of the prior distribution in whole-genome regression models for dissecting complex traits in what is now a standard situation with genomic data where the number of unknown parameters (p) typically exceeds sample size (n). Members of the alphabet aim to confront this overparameterization in various manners, but it is shown here that the prior is always influential, unless n ≫ p. This happens because parameters are not likelihood identified, so Bayesian learning is imperfect. Since inferences are not devoid of the influence of the prior, claims about genetic architecture from these methods should be taken with caution. However, all such procedures may deliver reasonable predictions of complex traits, provided that some parameters ("tuning knobs") are assessed via a properly conducted cross-validation. It is concluded that members of the alphabet have a room in whole-genome prediction of phenotypes, but have somewhat doubtful inferential value, at least when sample size is such that n ≪ p.

  15. 45 CFR 670.6 - Prior possession exception.

    Science.gov (United States)

    2010-10-01

    ... CONSERVATION OF ANTARCTIC ANIMALS AND PLANTS Prohibited Acts, Exceptions § 670.6 Prior possession exception. (a... captivity on or before October 28, 1978; or (2) Any offspring of such mammal, bird, or plant. (b... such act was not held in captivity on or before October 28, 1978, or was not an offspring referred to...

  16. Do Managers Manipulate Earnings Prior to Management Buyouts?

    NARCIS (Netherlands)

    Mao, Y.; Renneboog, L.D.R.

    2013-01-01

    Abstract: To address the question as to whether managers manipulate accounting numbers downwards prior to management buyouts (MBOs), we implement an industry-adjusted buyout-specific approach and receive an affirmative answer. In UK buyout companies, negative earnings manipulation (understating the

  17. routine saline infusion sonohysterography prior to assisted conception

    African Journals Online (AJOL)

    INTRODUCTION. The outcome of assisted reproductive technique largely depends on the receptivity of the endometrial lining of the uterus. Measures aimed at evaluating the uterine cavity prior to treatment are very vital for decision making and hence contribute to the overall success rate. The true prevalence of intrauterine ...

  18. Investigation into alternative sludge conditioning prior to dewatering

    CSIR Research Space (South Africa)

    Smollen, M

    1997-01-01

    Full Text Available have proven that the mixture of char and a small quantity of polyelectrolyte (0.5 to 1kg per ton of dry solids), used as a conditioner prior to centrifugation and filtration tests, produced cake solids concentration superior to that obtained by using...

  19. Extending Prior Posts in Dyadic Online Text Chat

    Science.gov (United States)

    Tudini, Vincenza

    2015-01-01

    This study explores whether chat users are able to extend prior, apparently completed posts in the dyadic online text chat context. Dyadic text chat has a unique turn-taking system, and most chat softwares do not permit users to monitor one another's written messages-in-progress. This is likely to impact on their use of online extensions as an…

  20. 13 CFR 305.14 - Occupancy prior to completion.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Occupancy prior to completion. 305.14 Section 305.14 Business Credit and Assistance ECONOMIC DEVELOPMENT ADMINISTRATION, DEPARTMENT OF... the Recipient's risk and must follow the requirements of local and State law. ...