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The Estimation of Tree Posterior Probabilities Using Conditional Clade Probability Distributions  

PubMed Central

In this article I introduce the idea of conditional independence of separated subtrees as a principle by which to estimate the posterior probability of trees using conditional clade probability distributions rather than simple sample relative frequencies. I describe an algorithm for these calculations and software which implements these ideas. I show that these alternative calculations are very similar to simple sample relative frequencies for high probability trees but are substantially more accurate for relatively low probability trees. The method allows the posterior probability of unsampled trees to be calculated when these trees contain only clades that are in other sampled trees. Furthermore, the method can be used to estimate the total probability of the set of sampled trees which provides a measure of the thoroughness of a posterior sample. [Bayesian phylogenetics; conditional clade distributions; improved accuracy; posterior probabilities of trees.] PMID:23479066

Larget, Bret



Large vocabulary decoding and confidence estimation using word posterior probabilities  

Microsoft Academic Search

The paper investigates the estimation of word posterior probabilities based on word lattices and presents applications of these posteriors in a large vocabulary speech recognition system. A novel approach to integrating these word posterior probability distributions into a conventional Viterbi decoder is presented. The problem of the robust estimation of confidence scores from word posteriors is examined and a method

G. Evermann; P. C. Woodland



How Accurately Does Current Fetal Imaging Identify Posterior Fossa Anomalies?  

PubMed Central

OBJECTIVE The first objective of our study was to describe the prevalence and spectrum of posterior fossa anomalies over 5 years in a major fetal care center where the referral diagnosis (by fetal sonography) was investigated by fetal MRI and, if confirmed, by postnatal MRI if possible. The second objective was to assess the accuracy with which fetal MRI predicts postnatal MRI findings in this population. MATERIALS AND METHODS We retrospectively identified all cases of suspected fetal posterior fossa anomalies referred to our center from 2002 through 2006. We reviewed maternal, fetal, neonatal, and follow-up records of all cases and fetal and early postnatal imaging studies. RESUlTS Of the 90 cases of suspected fetal posterior fossa anomalies (by fetal sonography) referred over the study period, 60 (67%) were confirmed by fetal MRI. Of 42 live-born infants, 39 (93%) underwent postnatal MRI. There was complete agreement in fetal and postnatal MRI diagnoses in 23 infants (59%). In 16 cases (41%), fetal and postnatal MRI diagnoses disagreed; postnatal MRI excluded fetal MRI diagnoses in six cases (15%) and revealed additional anomalies in 10 cases (26%). CONClUSION Although a valuable adjunct to fetal sonography in cases of suspected posterior fossa anomaly, current fetal MRI, particularly in early gestation, has limitations in accurately predicting postnatal MRI abnormalities. Advancing the accuracy of MRI for the diagnosis of posterior fossa anomalies will require greater understanding of normal brain development and improved tissue resolution of fetal MRI. During the interim, our findings strongly support the need for postnatal MRI follow-up in cases with suspected posterior fossa anomalies by fetal MRI. PMID:18492918

Limperopoulos, Catherine; Robertson, Richard L.; Khwaja, Omar S.; Robson, Caroline D.; Estroff, Judy A.; Barnewolt, Carole; Levine, Deborah; Morash, Donna; Nemes, Luanne; Zaccagnini, Linda; du Plessis, Adre J.



Information and Posterior Probability Criteria for Model Selection in Local Likelihood Estimation  

E-print Network

Information and Posterior Probability Criteria for Model Selection in Local Likelihood Estimation data sets. KEY WORDS: Information Criteria; Posterior Probability Criteria; Model Selection; Local behind the information and posterior probability criteria and develops criteria for weighted estimates

Irizarry, Rafael A.


Frequentist Properties of Bayesian Posterior Probabilities of Phylogenetic Trees Under Simple and Complex Substitution Models  

Microsoft Academic Search

What does the posterior probability of a phylogenetic tree mean? This simulation study shows that Bayesian posterior probabilities have the meaning that is typically ascribed to them; the posterior probability of a tree is the probability that the tree is correct, assuming that the model is correct. At the same time, the Bayesian method can be sensitive to model misspecification,

John Huelsenbeck; Bruce Rannala



Classifier Conditional Posterior Probabilities Robert P.W. Duin, David M.J. Tax  

E-print Network

Classifier Conditional Posterior Probabilities Robert P.W. Duin, David M.J. Tax Pattern Recognition Classifiers based on probability density estimates can be used to find posterior probabilities for the objects to be classified. These probabilities can be used for rejection or for combining classifiers. Posterior

Duin, Robert P.W.


Predicting accurate probabilities with a ranking loss  

PubMed Central

In many real-world applications of machine learning classifiers, it is essential to predict the probability of an example belonging to a particular class. This paper proposes a simple technique for predicting probabilities based on optimizing a ranking loss, followed by isotonic regression. This semi-parametric technique offers both good ranking and regression performance, and models a richer set of probability distributions than statistical workhorses such as logistic regression. We provide experimental results that show the effectiveness of this technique on real-world applications of probability prediction.

Menon, Aditya Krishna; Jiang, Xiaoqian J; Vembu, Shankar; Elkan, Charles; Ohno-Machado, Lucila



Accurate Approximations for Posterior Moments and Marginal Densities  

Microsoft Academic Search

This article describes approximations to the posterior means and variances of positive functions of a real or vector-valued parameter, and to the marginal posterior densities of arbitrary (i.e., not necessarily positive) parameters. These approximations can also be used to compute approximate predictive densities. To apply the proposed method, one only needs to be able to maximize slightly modified likelihood functions

Luke Tierney; Joseph B. Kadane



Estimating the Posterior Probabilities Using the K-Nearest Neighbor Rule  

E-print Network

Estimating the Posterior Probabilities Using the K-Nearest Neighbor Rule Amir F. Atiya Dept is needed. In this paper we propose a new posterior probability estimator. The proposed estimator considers to the posterior probability estimate. The weights corresponding to the K-nearest-neighbors (which add to 1

Abu-Mostafa, Yaser S.


Real-time word confidence scoring using local posterior probabilities on tree trellis search  

Microsoft Academic Search

Confidence scoring based on word posterior probability is usually performed as a post process of speech recognition decoding, and also needs a large number of word hypotheses to get enough confidence quality. We propose a simple way of computing the word confidence using estimated posterior probability while decoding. At the word expansion of stack decoding search, the local sentence likelihoods

Akinobu LEE; Kiyohiro SHIKANO; Tatsuya KAWAHARA



Effects of Branch Length Uncertainty on Bayesian Posterior Probabilities for Phylogenetic Hypotheses  

E-print Network

Effects of Branch Length Uncertainty on Bayesian Posterior Probabilities for Phylogenetic probability--the probability that a tree or clade is true given the data, evolutionary model, and prior an assumed prior probability distribution for each parameter. Little is known about the effects

Oregon, University of


Making binary decisions based on the posterior probability distribution associated with tomographic reconstructions  

SciTech Connect

An optimal solution to the problem of making binary decisions about a local region of a reconstruction is provided by the Bayesian method. The decision is made on the basis of the ratio of the posterior probabilities for the two hypotheses. The full Bayesian procedure requires an integration of the posterior probability over all possible values of the image outside the local region being analyzed. In the present work, this full treatment is replaced by the maximum value of the posterior probability obtained when the exterior region is varied, but the interior is fixed at both hypothesized functional forms. A Monte Carlo procedure is employed to evaluate the usefulness of the technique in a signal-known-exactly detection task in a noisy four-view tomographic reconstruction situation. 27 refs., 2 figs., 1 tab.

Hanson, K.M.



On Using Entropy Information to Improve Posterior Probability-based Confidence Measures  

E-print Network

-world applications usually degrades dramatically compared to that of laboratory ASR systems. Therefore, verifying. In this paper, we propose a novel approach that reduces the confidence error rate of traditional posterior probability-based confidence measures. The relative reductions in the confidence error rate are 14.11% and 9

Wang, Hsin-Min


Efficient marginalization to compute protein posterior probabilities from shotgun mass spectrometry data  

PubMed Central

The problem of identifying proteins from a shotgun proteomics experiment has not been definitively solved. Identifying the proteins in a sample requires ranking them, ideally with interpretable scores. In particular, “degenerate” peptides, which map to multiple proteins, have made such a ranking difficult to compute. The problem of computing posterior probabilities for the proteins, which can be interpreted as confidence in a protein’s presence, has been especially daunting. Previous approaches have either ignored the peptide degeneracy problem completely, addressed it by computing a heuristic set of proteins or heuristic posterior probabilities, or by estimating the posterior probabilities with sampling methods. We present a probabilistic model for protein identification in tandem mass spectrometry that recognizes peptide degeneracy. We then introduce graph-transforming algorithms that facilitate efficient computation of protein probabilities, even for large data sets. We evaluate our identification procedure on five different well-characterized data sets and demonstrate our ability to efficiently compute high-quality protein posteriors. PMID:20712337

Serang, Oliver; MacCoss, Michael J.; Noble, William Stafford



Estimating accurate multi-class probabilities with support vector machines  

Microsoft Academic Search

In this paper, we propose a comparison of several post-processing methods for estimating multi-class probabilities with standard support vector machines. The different approaches have been tested on a real pattern recognition problem with a large number of training samples. The best results have been obtained by using a \\

Jonathan Milgram; Mohamed Cheriet; R. Sabourin



Land-use/land-cover change detection using change-vector analysis in posterior probability space  

NASA Astrophysics Data System (ADS)

Land use/land cover change is an important field in global environmental change research. Remote sensing is a valuable data source from which land use/land cover change information can be extracted efficiently. A number of techniques for accomplishing change detection using satellite imagery have been formulated, applied, and evaluated, which can be generally grouped into two types. (1) Those based on spectral classification of the input data such as post-classification comparison and direct two-date classification; and (2) those based on radiometric change between different acquisition dates. The shortage of type 1 is cumulative error in image classification of an individual date. However, radiometric change approaches has a strict requirement for reliable image radiometry. In light of the above mentioned drawbacks of those two types of change detection methods, this paper presents a new method named change vector analysis in posterior probability space (CVAPS). Change-vector analysis (CVA) is one of the most successful radiometric change-based approaches. CVAPS approach incorporates post-classification comparison method and CVA approach, which is expected to inherit the advantages of two traditional methods and avoid their defects at the same time. CVAPS includes the following four steps. (1) Images in different periods are classified by certain classifier which can provide posterior probability output. Then, the posterior probability can be treated as a vector, the dimension of which is equal to the number of classes. (2) A procedure similar with CVA is employed. Compared with traditional CVA, new method analyzes the change vector in posterior probability space instead of spectral feature space. (3) A semiautomatic method, named Double-Window Flexible Pace Search (DFPS), is employed to determine the threshold of change magnitude. (4) Change category is discriminated by cosines of the change vectors. CVAPS approach was applied and validated by a case study of land use change detection in urban area of Shenzhen, China using multi-temporal TM data. Kappa coefficients of "change/no-change" detection and "from-to" types of change detection were employed for accuracy assessment. The experimental results show that CVAPS outperform than post-classification comparison method and can avoid cumulative error effectively. Besides, radiometric correction is not needed in this method compared with traditional CVA. Therefore, it is indicated that CVAPS is potentially useful in land-use/land-cover change detection.

Chen, Xuehong; Chen, Jin; Shen, Miaogen; Yang, Wei



Accurate Atomic Transition Probabilities for Hydrogen, Helium, and Lithium W. L. Wiese and J. R. Fuhra...  

E-print Network

Accurate Atomic Transition Probabilities for Hydrogen, Helium, and Lithium W. L. Wiese and J. R September 2009 We have carried out a comprehensive tabulation of the atomic transition probabilities probabilities of lines between different principal quantum numbers. © 2009 by the U. S. Secretary of Commerce

Magee, Joseph W.


Binary tree of posterior probability support vector machines for hyperspectral image classification  

NASA Astrophysics Data System (ADS)

The problem of hyperspectral remote sensing images classification is revisited by posterior probability support vector machines (PPSVMs). To address the multiclass classification problem, PPSVMs are extended using binary tree structure and boosting with the Fisher ratio as class separability measure. The class pair with larger Fisher ratio separability measure is separated at upper nodes of the binary tree to optimize the structure of the tree and improve the classification accuracy. Two approaches are proposed to select the class pair and construct the binary tree. One is the so-called some-against-rest binary tree of PPSVMs (SBT), in which some classes are separated from the remaining classes at each node considering the Fisher ratio separability measure. For the other approach, named one-against-rest binary tree of PPSVMs (OBT), only one class is separated from the remaining classes at each node. Both approaches need only to train n - 1 (n is the number of classes) binary PPSVM classifiers, while the average convergence performance of SBT and OBT are O(log2n) and O[(n! - 1)/n], respectively. Experimental results show that both approaches obtain classification accuracy if not higher, at least comparable to other multiclass approaches, while using significantly fewer support vectors and reduced testing time.

Wang, Dongli; Zhou, Yan; Zheng, Jianguo



Fast and Accurate Estimation of Nano-Scaled SRAM Read Failure Probability using Critical Point Sampling  

E-print Network

Fast and Accurate Estimation of Nano-Scaled SRAM Read Failure Probability using Critical Point-scale SRAM stability an extremely challenging task. In this paper, we propose a new method to detect the read failure in a SRAM cell using Critical Point Sampling technique. Using this technique, we propose two types

Kim, Chris H.



Microsoft Academic Search

In this work we try to estimate a posteriori probabilities neededforspeechrecognitionbytheK-Nearest-Neighbors rule (KNN), using a Multi-Layered Perceptrom (MLP) to obtain the distances between neighbors. Thus, we can distinguish two different works: on the one hand, we es- timate a posteriori probabilities using KNN with the aim of using them in a speech recognition system (1)(2); and, on the other hand,

Ana I. García Moral; Carmen Peláez Moreno; Hervé Bourlard



Adaptive recognition method based on posterior use of distribution pattern of output probabilities  

Microsoft Academic Search

Proposes a new adaptation scheme for speaker-independent recognition. The basic idea lies in the change of the likelihood from ordinary HMM scores to combined observational scores. The new likelihood is computed based on a combination of HMM scores which we call a `pattern of output probabilities distribution' (POPD). The system needs to calculate only the POPD for each new speaker.

Jin-Song Zhang; Beiqian Dai; Changfu Wang; HingKeung Kwan; Keikichi Hirose



Validation of a bayesian belief network representation for posterior probability calculations on national crime victimization survey  

Microsoft Academic Search

This paper presents an effort to induce a Bayesian belief network (BBN) from crime data, namely the national crime victimization\\u000a survey (NCVS). This BBN defines a joint probability distribution over a set of variables that were employed to record a set\\u000a of crime incidents, with particular focus on characteristics of the victim. The goals are to generate a BBN to

Michael Riesen; Gürsel Serpen



A three-step Maximum-A-Posterior probability method for InSAR data inversion of coseismic rupture with application to four recent large earthquakes in Asia  

NASA Astrophysics Data System (ADS)

We develop a three-step Maximum-A-Posterior probability (MAP) method for coseismic rupture inversion, which aims at maximizing the a posterior probability density function (PDF) of elastic solutions of earthquake rupture. The method originates from the Fully Bayesian Inversion (FBI) and the Mixed linear-nonlinear Bayesian inversion (MBI) methods , shares the same a posterior PDF with them and keeps most of their merits, while overcoming its convergence difficulty when large numbers of low quality data are used and improving the convergence rate greatly using optimization procedures. A highly efficient global optimization algorithm, Adaptive Simulated Annealing (ASA), is used to search for the maximum posterior probability in the first step. The non-slip parameters are determined by the global optimization method, and the slip parameters are inverted for using the least squares method without positivity constraint initially, and then damped to physically reasonable range. This step MAP inversion brings the inversion close to 'true' solution quickly and jumps over local maximum regions in high-dimensional parameter space. The second step inversion approaches the 'true' solution further with positivity constraints subsequently applied on slip parameters using the Monte Carlo Inversion (MCI) technique, with all parameters obtained from step one as the initial solution. Then the slip artifacts are eliminated from slip models in the third step MAP inversion with fault geometry parameters fixed. We first used a designed model with 45 degree dipping angle and oblique slip, and corresponding synthetic InSAR data sets to validate the efficiency and accuracy of method. We then applied the method on four recent large earthquakes in Asia, namely the 2010 Yushu, China earthquake, the 2011 Burma earthquake, the 2011 New Zealand earthquake and the 2008 Qinghai, China earthquake, and compared our results with those results from other groups. Our results show the effectiveness of the method in earthquake studies and a number of advantages of it over other methods. The details will be reported on the meeting.

Sun, J.; Shen, Z.; Burgmann, R.; Liang, F.




NSDL National Science Digital Library

Using different probabilities Help cybersquad clean up the buggy mess. Which bugs will Probability show up? Try out all the probability Possibilities. Find the answers to these Ratio activities. Practice Ratios and Proportions. ...

Marsh, Mrs.




NSDL National Science Digital Library

This application demomstrates simple probability concepts by having student rank the probability of an event on a probability line (from impossible to certain). After several trials the application then allows students to complete a simulation and collect data based on the probability task (retrieving balls from a machine). Several guiding questions are provided throughout the activity to encourage student dialogue.



Drug testing example for conditional probability Suppose that a drug test for an illegal drug is such that it is 98% accurate in the case of a  

E-print Network

Drug testing example for conditional probability Suppose that a drug test for an illegal drug is such that it is 98% accurate in the case of a user of that drug (e.g. it produces a positive result with probability .98 in the case that the tested individual uses the drug) and 90% accurate in the case of a non

Gross, Louis J.


Assessing Goodness of Fit in Item Response Theory with Nonparametric Models: A Comparison of Posterior Probabilities and Kernel-Smoothing Approaches  

ERIC Educational Resources Information Center

The distance between nonparametric and parametric item characteristic curves has been proposed as an index of goodness of fit in item response theory in the form of a root integrated squared error index. This article proposes to use the posterior distribution of the latent trait as the nonparametric model and compares the performance of an index…

Sueiro, Manuel J.; Abad, Francisco J.



Drug testing Example for Conditional Probability and Bayes Theorem Suppose that a drug test for an illegal drug is such that it is 98% accurate in the case of a  

E-print Network

Drug testing Example for Conditional Probability and Bayes Theorem Suppose that a drug test for an illegal drug is such that it is 98% accurate in the case of a user of that drug (e.g. it produces a positive result with probability .98 in the case that the tested individual uses the drug) and 90% accurate

Gross, Louis J.


Probability Probability  

E-print Network

(x,y,z) Marginal Probabilities #15;We can "sum out" part of a joint distribution to get the marginal distribution;ne random variables and sample spaces carefully: e.g. Prisoner's paradox Entropy #15; Measures H(p) = 0. #15; Maximal value when p is uniform. #15; Tells you the expected "cost" if each event

Roweis, Sam



E-print Network

upon both acoustic and language model information for data drawn from the Broadcast News corpus by a trigram language model is reduced for Broadcast News data. We also argue that acoustic confidence measures or some unclear acoustics, caused by noise or a high level of background music. Both OOV words and unclear

Edinburgh, University of


A Posteriori Transit Probabilities  

NASA Astrophysics Data System (ADS)

Given the radial velocity (RV) detection of an unseen companion, it is often of interest to estimate the probability that the companion also transits the primary star. Typically, one assumes a uniform distribution for the cosine of the inclination angle i of the companion's orbit. This yields the familiar estimate for the prior transit probability of ˜R*, given the primary radius R* and orbital semimajor axis a, and assuming small companions and a circular orbit. However, the posterior transit probability depends not only on the prior probability distribution of i but also on the prior probability distribution of the companion mass Mc, given a measurement of the product of the two (the minimum mass Mcsin i) from an RV signal. In general, the posterior can be larger or smaller than the prior transit probability. We derive analytic expressions for the posterior transit probability assuming a power-law form for the distribution of true masses, d?/dMc?Mc?, for integer values -3?? ? 3. We show that for low transit probabilities, these probabilities reduce to a constant multiplicative factor f? of the corresponding prior transit probability, where f? in general depends on ? and an assumed upper limit on the true mass. The prior and posterior probabilities are equal for ?. The posterior transit probability is ˜1.5 times larger than the prior for ? = -3 and is ˜4/? times larger for ? = -2, but is less than the prior for ??0, and can be arbitrarily small for ? > 1. We also calculate the posterior transit probability in different mass regimes for two physically-motivated mass distributions of companions around Sun-like stars. We find that for Jupiter-mass planets, the posterior transit probability is roughly equal to the prior probability, whereas the posterior is likely higher for Super-Earths and Neptunes (10 M?-30 M?) and Super-Jupiters (MJup-10 MJup), owing to the predicted steep rise in the mass function toward smaller masses in these regimes. We therefore suggest that companions with minimum masses in these regimes might be better-than-expected targets for transit follow-up, and we identify promising targets from RV-detected planets in the literature. Finally, we consider the uncertainty in the transit probability arising from uncertainties in the input parameters, and the effect of ignoring the dependence of the transit probability on the true semimajor axis on i.

Stevens, Daniel J.; Gaudi, B. Scott



A Likelihood Model That Accounts for Censoring Due to Fetal Loss Can Accurately Test the Effects of Maternal and Fetal Genotype on the Probability of Miscarriage  

PubMed Central

Objective Heritable maternal and fetal thrombophilia and/or hypofibrinolysis are important causes of miscarriage. Under the constraint that fetal genotype is observed only after a live birth, estimating risk is complicated. Censoring prevents use of published statistical methodology. We propose techniques to determine whether increases in miscarriage are due to the fetal genotype, maternal genotype, or both. Methods We propose a study to estimate the risk of miscarriage contributed by an allele, expressed in either dominant or recessive fashion. Using a multinomial likelihood, we derive maximum likelihood estimates of risk for different genotype groups. We describe likelihood ratio tests and a planned hypothesis testing strategy. Results Parameter estimation is accurate (bias <0.0011, root mean squared error <0.0780, n = 500). We used simulation to estimate power for studies of three gene mutations: the 4G hypofibrinolytic mutation in the plasminogen activator inhibitor gene (PAI-1), the prothrombin G20210A mutation, and the Factor V Leiden mutation. With 500 families, our methods have approximately 90% power to detect an increase in the miscarriage rate of 0.2, above a background rate of 0.2. Conclusion Our statistical method can determine whether increases in miscarriage are due to fetal genotype, maternal genotype, or both despite censoring. PMID:18931510

O'Donnell, Colin I.; Glueck, Charles J.; Fingerlin, Tasha E.; Glueck, Deborah H.



Posterior fossa malformations.  


Understanding embryologic development of the cerebellum and the 4th ventricle is essential for understanding posterior fossa malformations. Posterior fossa malformations can be conveniently classified into those that have a large posterior fossa and those with normal or small posterior fossa. Disorders associated with a large posterior fossa include classic Dandy-Walker malformation, Blake's pouch cyst, mega cisterna magna, and posterior fossa arachnoid cyst. Disorders associated with normal or small posterior fossa include Dandy-Walker variant, Joubert syndrome, tecto-cerebellar dysraphia, rhombencephalosynapsis, the neocerebellar hypoplasias, and cerebellar atrophy. Neuro-imaging features should enable the imager to provide the referring physician a logical approach to these complex posterior fossa malformations. PMID:21596278

Shekdar, Karuna



Robust and accurate fundamental matrix estimation with propagated matches  

NASA Astrophysics Data System (ADS)

Two perspective images of a single scene taken by uncalibrated cameras are related by a fundamental matrix, which is the key to solving many computer vision problems. We present a new robust and accurate algorithm to estimate the fundamental matrix, which is suitable for wide baseline stereo pairs. The estimation algorithm includes two stages. The first stage is that more affine invariant matching points are determined by a propagation process. In this stage, an affine iterative optimization model is used to accurately detect matching points at the subpixel level. And a new matching cost function is proposed that is more robust to outliers and more effective for images with single texture and repetitive texture. In the second stage, a resampling model based on the posterior probability is presented in order to optimize the fundamental matrix with more accurate matching points. The experiment results show that our algorithm is very robust to outliers, and the fundamental matrix with high accuracy can be estimated.

Wan, Yanli; Miao, Zhenjiang; Tang, Zhen



Posterior fossa tumor  


... and cause increased pressure on the brain and spinal cord. Most tumors of the posterior fossa are primary brain cancers . They start in the brain, rather than spreading from somewhere else ... Posterior fossa tumors have no known causes or risk factors.


Posterior instrumentation in scoliosis  

Microsoft Academic Search

The aims of posterior fusion and instrumentation in scoliosis are to achieve and maintain correction of the deformity and balance the spine in three planes, whilst keeping the fusion as short as possible and protecting the spinal cord. Harrington developed the first generation of posterior instrumentation, which considered only frontal plane correction. Since that time there has been an evolution

J. K. Webb; R. G. Burwell; A. A. Cole; I. Lieberman



Evaluation of posterior fossa lesions by computer assisted tomography (CAT).  


Valuable neuroradiologic information can be obtained with routine examination of the posterior fossa by computer assisted tomography (CAT). The diagnosis can be difficult in the posterior fossa due to the relatively small size of the compartment and its proximities to large bony masses and air in the mastoid cells. However, many lesions can be accurately diagnosed when close attention is given to anatomic detail and the frequent use of contrast enhancement. We introduced a new CAT classification of posterior fossa neoplasms. PMID:877637

Lott, T; El Gammal, T; Volcan, I



Establishing the posterior palatal seal during the final impression stage.  


A procedure for adding a posterior palatal seal at the final impression stage with green stick modeling compound is described. The location and degree of tissue displacement of the posterior palatal seal area are controlled by the dentist. This procedure is suggested to be more accurate than the arbitrary scraping of the master cast. PMID:9297652

Ansari, I H



Establishing the posterior palatal seal during the final impression stage  

Microsoft Academic Search

A procedure for adding a posterior palatal seal at the final impression stage with green stick modeling compound is described. The location and degree of tissue displacement of the posterior palatal seal area are controlled by the dentist. This procedure is suggested to be more accurate than the arbitrary scraping of the master cast. (J Prosthet Dent 1997;78: 324-6.)

Izharul Haque Ansari



Posterior Tibial Tendon Dysfunction  


... patients will notice some limitation in activity a er surgery. Anatomy The posterior tibial tendon is one ... the pain to last another 6 months a er treatment starts. Rest Decreasing or even stopping activities ...


Posterior tracheal diverticulosis.  


Multiple tracheal diverticulosis is a rare clinical entity. Tracheal diverticula are usually recognized radiologically as solitary right paratracheal air collections on thoracic computed tomography examination. They are usually asymptomatic but can occasionally present with persistent symptoms. We herein report the case of a 50-year-old male patient who underwent extensive evaluation for persistent cough. Multiple posterior right paratracheal air collections were recognized on thoracic multidetector computed tomography examination, which was confirmed as multiple-acquired posterior upper tracheal diverticula on flexible bronchoscopy. The patient improved with conservative medical management. PMID:25321454

Madan, Karan; Das, Chandan J; Guleria, Randeep




E-print Network

likelihood maximization and relative entropy mini- mization, without making the common assumption of in of maximum likelihood (ML), and generalizes the ideas of conditional and marginal likelihood. PL allows and the data XI, x2, ,XN is written as the product N N i=l i=1 The relative entropy (RE), or the Kullback

Adali, Tulay


Novel posterior fixation keratoprosthesis  

NASA Astrophysics Data System (ADS)

The keratoprosthesis is the last solution for corneally blind patients that cannot benefit from corneal transplants. Keratoprostheses that have been designed to be affixed anteriorly usually necessitate multi-step surgical procedures and are continuously subjected to the extrusion forces generated by the positive intraocular pressure; therefore, clinical results in patients prove inconsistent. We proposed a novel keratoprosthesis concept that utilizes posterior corneal fixation which `a priori' minimizes the risk of aqueous leakage and expulsion. This prosthesis is implanted in a single procedure thereby reducing the number of surgical complications normally associated with anterior fixation devices. In addition, its novel design makes this keratoprosthesis implantable in phakic eyes. With an average follow-up of 13 months (range 3 to 25 months), our results on 21 cases are encouraging. Half of the keratoprostheses were implanted in severe burn cases, with the remainder in cases of pseudo- pemphigus. Good visual results and cosmetic appearance were obtained in 14 of 21 eyes.

Lacombe, Emmanuel



Probability Propagation  

E-print Network

In this paper we give a simple account of local computation of marginal probabilities for when the joint probability distribution is given in factored form and the sets of variables involved in the factors form a hypertree. Previous expositions...

Shafer, Glenn R.; Shenoy, Prakash P.



An Alternative Version of Conditional Probabilities and Bayes' Rule: An Application of Probability Logic  

ERIC Educational Resources Information Center

This paper presents an alternative version of formulas of conditional probabilities and Bayes' rule that demonstrate how the truth table of elementary mathematical logic applies to the derivations of the conditional probabilities of various complex, compound statements. This new approach is used to calculate the prior and posterior probabilities…

Satake, Eiki; Amato, Philip P.



Exponential Probabilities  

NSDL National Science Digital Library

The applet, created by Virginia Tech's Department of Statistics, allows you see how probabilities are determined from the exponential distribution. The user determines the mean of the distribution and the limits of probability. Three different probability expressions are available. Click "Calculate" to see the pdf and the cdf. The probability is highlighted in green on the pdf. This is a nice reference tool for anyone studying statistics.

Anderson-Cook, C.; Dorai-Raj, S.; Robinson, T.



Probability Spaces  

NSDL National Science Digital Library

Created by Kyle Siegrist of the University of Alabama-Huntsville, this is an online, interactive lesson on probability spaces. The resource provides examples, exercises, and applets that cover conditional probability, independence, and several modes of convergence that are appropriate for random variables. This section also covers probability space, the paradigm of a random experiment and its mathematical model as well as sample spaces, events, random variables, and probability measures. This is the second of seventeen different statistics lessons provided by Siegrist.

Siegrist, Kyle



Posterior wall prolapse and repair.  


Most posterior wall defects occur in combination with other pelvic support disorders. Some patients with rectoceles, the most common posterior wall defect, are asymptomatic, whereas others experience a range of symptoms from a sensation of lower pelvic fullness to defecatory and/or sexual dysfunction. If patients are symptomatic, rectoceles can be treated conservatively with pelvic floor physiotherapy, behavioral therapy, or pessaries. Surgically, the most common rectocele repair is a traditional posterior colporrhaphy which provides excellent cure rates of up to 95%. The studies published to date do not support the use of biologic or synthetic absorbable grafts in reconstructive surgical procedures of the posterior compartment as these repairs have not improved anatomic or functional outcomes over traditional posterior colporrhaphy. PMID:20142644

Kudish, Bela I; Iglesia, Cheryl B



Classification of posterior vitreous detachment  

PubMed Central

Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography (OCT). By biomicroscopy, the vitreous condition is determined based on the presence or absence of a PVD. The PVD then is classified as either a complete posterior vitreous detachment (C-PVD) or a partial posterior vitreous detachment (P-PVD). A C-PVD is further divided into a C-PVD with collapse and a C-PVD without collapse, while a P-PVD is divided into a P-PVD with shrinkage of the posterior hyaloid membrane (P-PVD with shrinkage) and a P-PVD without shrinkage of the posterior hyaloid membrane (P-PVD without shrinkage). A P-PVD without shrinkage has a subtype characterized by vitreous gel attachment through the premacular hole in a posterior hyaloid membrane to the macula (P-PVD without shrinkage [M]). By OCT, a shallow PVD is classified as the absence of a shallow PVD or as a shallow PVD. A shallow PVD is then subclassified as a shallow PVD without shrinkage of the posterior vitreous cortex, a shallow PVD with shrinkage of the posterior vitreous cortex, and a peripheral shallow PVD. A shallow PVD without shrinkage of the posterior vitreous cortex has two subtypes: an age-related shallow PVD and a perifoveal PVD associated with a macular hole. PMID:24376338

Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun



T Probabilities  

NSDL National Science Digital Library

The applet, created by Virginia Tech's Department of Statistics, allows you to see how the T distribution is related to the Standard Normal distribution by calculating probabilities. The T distribution is primarily used to make inferences on a Normal mean when the variance is unknown. If the variance is known inference on the mean can be done using the Standard Normal. The user has a choice of three different probability expressions, then can change the degrees of freedom and the limits of probability.

Anderson-Cook, C.; Dorai-Raj, S.; Robinson, T.



Approximating Model Probabilities in Bayesian Information Criterion and Decision-Theoretic Approaches to Model  

E-print Network

Approximating Model Probabilities in Bayesian Information Criterion and Decision (DT) approaches rely on a conservative approximationto estimate the posterior probability of a given to directly estimate model probabilities for an extended candidate pool of all 406 special cases

Sullivan, Jack


Posterior cranial fossa tumors: Results and prognostic factors in a consecutive series of 14 operated patients by occipital transtentorial approach  

PubMed Central

Background: The objective of our study was to determine the safety and usefulness of performing surgery via occipital transtentorial approach to treat posterior cranial fossa tumors, which is well known as an approach to the pineal region (Poppen's approach). Methods: Fourteen patients with posterior cranial fossa tumors were successfully treated using occipital transtentorial approach between 2007 and 2012. The lesions included five meningiomas, three astrocytomas, two metastases, two hemangioblastomas, one cavernoma, and one dysgerminoma. Results: Lesions were <3 cm in 12 cases and ?3 cm in two cases. Average Karnofsky Performance Status (KPS) scoring at admission was 88.5. Eleven patients scored ?70 and seven patients <70. Average age was 43.1 years. All patients underwent surgical treatment by the same surgical team. All tumors were completely removed surgically without any injury to the venous complex and the adjoining structures. There was no incidence of mortality or morbidity in all patients, and all functional outcomes were good to excellent postoperatively. Postoperative computed tomography (CT) imaging revealed that none of the patients had suffered brain damage or infarction around the cerebellum, brainstem, or occipital lobe. Conclusions: We found that the use of occipital transtentorial approach is strongly supported by the successful removal of posterior cranial fossa tumors without serious complications. Open microneurosurgery is probably still the most effective therapy in improving survival and KPS in patients with posterior cranial fossa tumors, given that the proper surgical technique is used and complications do not occur. This case study has strongly suggested that this approach is very useful, safe, and accurate for removing the tumors of posterior fossa and evaluating the surrounding anatomy, as well as for determining operative strategy. PMID:23050200

Maselli, Giuliano; De Paulis, Danilo; Ricci, Alessandro; Galzio, Renato J.



Posterior cruciate ligament (PCL) injury  


... extends from the top-rear surface of the tibia (bone between the knee and ankle) to the ... from posterior instability. This means it prevents the tibia from moving too much and going behind the ...


Probability Theory  

NASA Astrophysics Data System (ADS)

Foreword; Preface; Part I. Principles and Elementary Applications: 1. Plausible reasoning; 2. The quantitative rules; 3. Elementary sampling theory; 4. Elementary hypothesis testing; 5. Queer uses for probability theory; 6. Elementary parameter estimation; 7. The central, Gaussian or normal distribution; 8. Sufficiency, ancillarity, and all that; 9. Repetitive experiments, probability and frequency; 10. Physics of 'random experiments'; Part II. Advanced Applications: 11. Discrete prior probabilities, the entropy principle; 12. Ignorance priors and transformation groups; 13. Decision theory: historical background; 14. Simple applications of decision theory; 15. Paradoxes of probability theory; 16. Orthodox methods: historical background; 17. Principles and pathology of orthodox statistics; 18. The Ap distribution and rule of succession; 19. Physical measurements; 20. Model comparison; 21. Outliers and robustness; 22. Introduction to communication theory; References; Appendix A. Other approaches to probability theory; Appendix B. Mathematical formalities and style; Appendix C. Convolutions and cumulants.

Jaynes, E. T.; Bretthorst, G. Larry



Probability Calculator  

NSDL National Science Digital Library

This tool lets you calculate the probability that a random variable X is in a specified range, for a variety of probability distributions for X: the normal distribution, the binomial distribution with parameters n and p, the chi-square distribution, the exponential distribution, the geometric distribution, the hypergeometric distribution, the negative binomial distribution, the Poisson distribution, and Student's t-distribution. The first choice box lets you select a probability distribution. Depending on the distribution you select, text areas will appear for you to enter the values of the parameters of the distribution. Parameters that are probabilities (e.g., the chance of success in each trial for a binomial distribution) can be entered either as decimal numbers between 0 and 1, or as percentages. If you enter a probability as a percentage, be sure to include the percent sign (%) after the number.

Stark, Philip B.



Practically Probable  

NSDL National Science Digital Library

In this lesson, students will differentiate between likely and unlikely event, as well as learn the difference between dependent and independent events. Finally, they learn how to compute theoretical probabilities in simple experiments.

Dalton, Michele



Probability Boxes  

NSDL National Science Digital Library

In this cooperative learning activity students conduct an experiment in probability. For this lesson, students work in groups to pull items one at a time from mystery boxes, answering questions, and predicting outcomes for eight different boxes. Throughout this activity students learn to use the terms: possible, event, predict, probability, impossible, unlikely, equally likely, likely, certain, least likely, most likely, and as likely as. This lesson plan includes a data recording sheet and an assessment sheet in PDF format.



Experimental Probability  

NSDL National Science Digital Library

In this activity, students spin a spinner or roll dice to obtain experimental data for their trials. The applet keeps track of their experiments by tallying the results in a table. This activity allows students to explore experimental probabilities in order to compare them with theoretical probabilities. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.



Isolated Posterior Fossa Involvement in Posterior Reversible Encephalopathy Syndrome  

PubMed Central

Summary Posterior reversible encephalopathy syndrome (PRES) is characterized by reversible vasogenic edema affecting the subcortical white matter of bilateral occipital and parietal lobes. We describe a case of isolated posterior fossa involvement of PRES which occurred during remission induction chemotherapy for T-cell acute lymphoblastic leukemia. Both the brainstem and cerebellum were extensively involved, but the supratentorial structures were completely spared. The follow-up magnetic resonance images revealed reversibility of most lesions. The knowledge of atypical radiological features of PRES is essential for prompt diagnosis. PMID:24199811

Shimizu, Yukie; Tha, Khin Khin; Iguchi, Akihiro; Cho, Yuko; Yoshida, Atsushi; Fujima, Noriyuki; Tsukahara, Akiko; Shirato, Hiroki; Terae, Satoshi



Quantum probabilities as Bayesian probabilities  

E-print Network

In the Bayesian approach to probability theory, probability quantifies a degree of belief for a single trial, without any a priori connection to limiting frequencies. In this paper we show that, despite being prescribed by a fundamental law, probabilities for individual quantum systems can be understood within the Bayesian approach. We argue that the distinction between classical and quantum probabilities lies not in their definition, but in the nature of the information they encode. In the classical world, maximal information about a physical system is complete in the sense of providing definite answers for all possible questions that can be asked of the system. In the quantum world, maximal information is not complete and cannot be completed. Using this distinction, we show that any Bayesian probability assignment in quantum mechanics must have the form of the quantum probability rule, that maximal information about a quantum system leads to a unique quantum-state assignment, and that quantum theory provides a stronger connection between probability and measured frequency than can be justified classically. Finally we give a Bayesian formulation of quantum-state tomography.

Carlton M. Caves; Christopher A. Fuchs; Ruediger Schack



Objective autorefraction in posterior chamber pseudophakia.  

PubMed Central

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 110 eyes (110 patients) six to eight weeks after they had undergone extracapsular cataract extraction with posterior chamber intraocular lens implantation and achieved a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 100 (91%) of these eyes. The agreement between autorefraction and clinical refraction data was 98% for spherical equivalence less than 0.51 dioptres (D), 95% for sphere power less than 0.51D, 94% for cylinder power less than 0.51D, and 85% for cylinder axis less than 11 degrees. Autorefraction can provide acceptably accurate postoperative refraction values in pseudophakic eyes. Images PMID:2275935

Raj, P S; Akingbehin, T; Levy, A M



Primary myelolipoma in posterior mediastinum  

PubMed Central

Myelolipoma in posterior mediastinum is indeed rare. As a benign tumor, it consists of mature fat with scattered foci of haematopoietic elements resembling bone marrow. The computed tomography (CT) and magnetic resonance imaging (MRI) are effective methods to detect them, while the definite diagnosis still depends on pathological diagnosis. Up to now, there is no standard treatment for this disease. Surgery is thought to be the best choice in some literatures reports. In this paper, two patients with primary posterior mediastinal tumor are reported, both of whom were underwent Video-assisted thoracoscopic surgery (VATS). Postoperative pathological diagnosis was myelolipoma.

Xiong, Yan; Wang, Yong



Primary myelolipoma in posterior mediastinum.  


Myelolipoma in posterior mediastinum is indeed rare. As a benign tumor, it consists of mature fat with scattered foci of haematopoietic elements resembling bone marrow. The computed tomography (CT) and magnetic resonance imaging (MRI) are effective methods to detect them, while the definite diagnosis still depends on pathological diagnosis. Up to now, there is no standard treatment for this disease. Surgery is thought to be the best choice in some literatures reports. In this paper, two patients with primary posterior mediastinal tumor are reported, both of whom were underwent Video-assisted thoracoscopic surgery (VATS). Postoperative pathological diagnosis was myelolipoma. PMID:25276393

Xiong, Yan; Wang, Yong; Lin, Yidan



Probability Sampling  

NSDL National Science Digital Library

This site, created by author William M.K. Trochim, describes in detail five different types of random sampling. Some of these types include: simple random, stratified random, systematic random, cluster random, multi-stage sampling. The author provides examples, definitions, and the procedures behind the methods. Overall, this site provides a nice overview of probability sampling.

Trochim, William M.



Probabilistic probability  

E-print Network

on #, is the entropy. . Thus, in the M­step, maximizing with respect to # for fixed q we only need to consider optimization easier. Expectation­Maximization (EM) Algorithm 2 . Iterative algorithm with two linked steps: E of a marginal probability: #(#;x) = log p(x|#) = log # z p(x, z|#) which is the incomplete log likelihood. #12

Roweis, Sam


Exploring Probability  

NSDL National Science Digital Library

This interactive mathematics resource allows the user to explore the outcomes resulting from tossing a coin, rolling a die, and using a spinner to perform single and double event probabilities. The resource includes print activities, solutions, learning strategies, and a board game.



Probably Graphing  

NSDL National Science Digital Library

Student will conduct a coin tossing experiment for 30 trials. Their results will be graphed, showing a line graph that progresses toward the theoretical probability. Students will observe that as the number of trials increases they begin to see a graphical representation of the Law of Large Numbers. Instructions, handouts, and a lesson extension are all included here.

Heitschmidt, Corey



Biocompatibility of posterior restorative materials.  


Biocompatibility of dental materials is an important consideration for the patient, clinician, laboratory technician and manufacturer. This paper examines biocompatibility testing methods and the biocompatibility of posterior restorative materials, including amalgam, casting alloys, resin composites, dentin bonding agents, cements, porcelains and ceramics. PMID:9120609

Schuster, G S; Lefebvre, C A; Wataha, J C; White, S N



Pig Data and Bayesian Inference on Multinomial Probabilities  

ERIC Educational Resources Information Center

Bayesian inference on multinomial probabilities is conducted based on data collected from the game Pass the Pigs[R]. Prior information on these probabilities is readily available from the instruction manual, and is easily incorporated in a Dirichlet prior. Posterior analysis of the scoring probabilities quantifies the discrepancy between empirical…

Kern, John C.



[Ossification of posterior longitudinal ligament].  


Ossification of posterior longitudinal ligament (OPLL) is a hyperostotic disease of the spine associated with myelopathy which is occurred by an anterior compression to the spinal cord. OPLL was first reported by Key GA in 1838, and was previously considered specific to east Asian people, especially Japanese. However, now OPLL is recognized as a subtype of diffuse idiopathic skeletal hyperosteosis, which is detected in Europe and the United States. We discuss the etiology and natural history of OPLL in this review. PMID:24473355

Watanabe, Ryuichi; Miyamoto, Takeshi



Posterior asymmetry and idiopathic scoliosis  

E-print Network

Study design Are there neuro-anatomical abnormalities associated with idiopathic scoliosis (IS)? Posterior Basicranium (PBA) reflects cerebellum growth and contains vestibular organs, two structures suspected to be involved in scoliosis. Objective The aim of this study was to compare posterior basicranium asymmetry (PBA) in Idiopathic scoliosis (IS) and normal subjects. Method: To measure the shape of PBA in 3D, we defined an intra-cranial frame of reference based on CNS and guided by embryology of the neural tube. Measurements concerned three directions of space referred to a specific intra cranial referential. Data acquisition was performed with T2 MRI (G.E. Excite 1.5T, mode Fiesta). We explored a scoliosis group of 76 women and 20 men with a mean age of 17, 2 and a control group of 26 women and 16 men, with a mean age of 27, 7. Results: IS revealed a significant asymmetry of PBA (Pr>|t|<.0001) in 3 directions of space compared to the control group. This asymmetry was more pronounced in antero-posterior...

Rousie, D L; Berthoz, A



Clinical measurement of posterior shoulder flexibility  

Microsoft Academic Search

The objectives of this study were to determine both the intra-rater reliability and the smallest real difference necessary to detect meaningful clinical changes over an 8–12 week period for three clinical measures of posterior shoulder flexibility. Posterior shoulder tightness has been associated with abnormal humeral head translations that narrow the subacromial space and contribute to impingement. Posterior shoulder stretching to

John D. Borstad; Krista M. Mathiowetz; Laura E. Minday; Bhakti Prabhu; Daisy E. Christopherson; Paula M. Ludewig



Gd Transition Probabilities and Abundances  

Microsoft Academic Search

Radiative lifetimes, accurate to +\\/- 5%, have been measured for 49 even-parity and 14 odd-parity levels of Gd II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of Gd II transition probabilities and the

E. A. Den Hartog; J. E. Lawler; C. Sneden; J. J. Cowan



Sm Transition Probabilities and Abundances  

Microsoft Academic Search

Radiative lifetimes, accurate to +\\/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This

J. E. Lawler; E. A. Den Hartog; C. Sneden; J. J. Cowan



Posterior dynamic stabilization systems: DYNESYS.  


Posterior dynamic stabilization systems have to neutralize injurious forces and restore painless function of the spine segments and protect the adjacent segments. Because degenerative disc disease has many clinical manifestations, pedicular screw systems and interspinous implants have their indications. A dynamic stabilization device has to provide stability throughout its lifetime, unless it activates or allows reparative processes with a reversal of the degenerative changes. Anchorage to the bone is crucial, at least for pedicular systems. This is a great demand on spinal implants and assumes rest and motion going together. Our experience with DYNESYS has shown that this method has limitations in elderly patients with osteoporotic bone or in patients with a severe segmental macro-instability combined with degenerative olisthesis and advanced disc degeneration. Such cases have an increased risk of failure. Only future randomized evaluations will be able to address the potential reduction of accelerated adjacent segment degeneration. The few posterior dynamic stabilization systems that have had clinical applications so far have produced clinical outcomes comparable with fusion. No severe adverse events caused by these implants have been reported. Long-term follow-up data and controlled prospective randomized studies are not available for most of the cited implants but are essential to prove the safety, efficacy, appropriateness, and economic viability of these methods. PMID:15950696

Schwarzenbach, Othmar; Berlemann, Ulrich; Stoll, Thomas M; Dubois, Gilles



Decoding Trajectories from Posterior Parietal Cortex Ensembles  

PubMed Central

High-level cognitive signals in the posterior parietal cortex (PPC) have previously been used to decode the intended endpoint of a reach, providing the first evidence that PPC can be used for direct control of a neural prosthesis (Musallam et al., 2004). Here we expand on this work by showing that PPC neural activity can be harnessed to estimate not only the endpoint but also to continuously control the trajectory of an end effector. Specifically, we trained two monkeys to use a joystick to guide a cursor on a computer screen to peripheral target locations while maintaining central ocular fixation. We found that we could accurately reconstruct the trajectory of the cursor using a relatively small ensemble of simultaneously recorded PPC neurons. Using a goal-based Kalman filter that incorporates target information into the state-space, we showed that the decoded estimate of cursor position could be significantly improved. Finally, we tested whether we could decode trajectories during closed-loop brain control sessions, in which the real-time position of the cursor was determined solely by a monkey’s neural activity in PPC. The monkey learned to perform brain control trajectories at 80% success rate(for 8 targets) after just 4–5 sessions. This improvement in behavioral performance was accompanied by a corresponding enhancement in neural tuning properties (i.e., increased tuning depth and coverage of encoding parameter space) as well as an increase in off-line decoding performance of the PPC ensemble. PMID:19036985

Mulliken, Grant H.; Musallam, Sam; Andersen, Richard A.



Reconstruction of Posterior Trunk Defects  

PubMed Central

The posterior trunk roughly encompasses the upper back from the shoulders to the lumbar area above the iliac crests. Long-term outcomes in the treatment of defects of the spine and bony thorax have been proved superior if flaps were used. Many local muscle and fasciocutaneous flaps are available alternatives. A guideline, patterned according to arbitrary anatomic territories of the back, is suggested as a starting point for the selection of appropriate primary and secondary flap options. Depending on flap availability, the latissimus dorsi and trapezius muscles are the workhorse flaps for the upper back, whereas perforator flaps have become a useful alternative for the lumbar region in lieu of free flaps. PMID:22294946

Hallock, Geoffrey G.



Posterior Lamellar Keratoplasty in Perspective  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Posterior lamellar keratoplasty (PLK) offers many substantial benefits compared to penetrating keratoplasty (PK) including:\\u000a closed eye surgery elimination of both regular and irregular postoperative astigmatism leading to full visual rehabilitation\\u000a with spectacles within 3–6 months, elimination of postoperative corneal anaesthesia, and a reduced risk of postoperative globe\\u000a rupture.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Disadvantages of PLK compared to PK include: corneal stromal scarring

F Arnalich-Montiel; JKG Dart


Multinomial mixture model with heterogeneous classification probabilities  

USGS Publications Warehouse

Royle and Link (Ecology 86(9):2505-2512, 2005) proposed an analytical method that allowed estimation of multinomial distribution parameters and classification probabilities from categorical data measured with error. While useful, we demonstrate algebraically and by simulations that this method yields biased multinomial parameter estimates when the probabilities of correct category classifications vary among sampling units. We address this shortcoming by treating these probabilities as logit-normal random variables within a Bayesian framework. We use Markov chain Monte Carlo to compute Bayes estimates from a simulated sample from the posterior distribution. Based on simulations, this elaborated Royle-Link model yields nearly unbiased estimates of multinomial and correct classification probability estimates when classification probabilities are allowed to vary according to the normal distribution on the logit scale or according to the Beta distribution. The method is illustrated using categorical submersed aquatic vegetation data. ?? 2010 Springer Science+Business Media, LLC.

Holland, M. D.; Gray, B. R.



Probability Primer 1 Running head: PROBABILITY PRIMER  

E-print Network

Probability Primer 1 Running head: PROBABILITY PRIMER A Primer on Probabilistic Inference Thomas L University of California, Los Angeles #12;Probability Primer 2 A Primer on Probabilistic Inference is as follows. First, we outline the fundamentals of Bayesian inference, which #12;Probability Primer 3

Yuille, Alan L.


Posterior Cruciate Ligament Removal Contributes to Abnormal Knee Motion during Posterior Stabilized Total Knee Arthroplasty  

E-print Network

Posterior Cruciate Ligament Removal Contributes to Abnormal Knee Motion during Posterior Stabilized Total Knee Arthroplasty Melinda J. Cromie,1,2 Robert A. Siston,1,2,3,4 Nicholas J. Giori,2,5 Scott L (20­608) following posterior stabilized total knee arthroplasty. The underlying biomechanical causes

Delp, Scott


Posterior ankle pain in dancers.  


Treatment of dancers can be as challenging as it is rewarding. Dancers often have unusual difficulties related to the altered kinesiology required by their individual dance form. A thorough understanding of these movements helps guide the physician to the cause of the disability, particularly in the setting of overuse injuries. This knowledge, coupled with a careful physical examination, is essential for the accurate diagnosis and treatment of the dancer, who is both artist and athlete. PMID:18346541

Hamilton, William G



Accurately determining inflationary perturbations  

E-print Network

Cosmic microwave anisotropy satellites promise extremely accurate measures of the amplitude of perturbations in the universe. We use a numerical code to test the accuracy of existing approximate expressions for the amplitude of perturbations produced by single-field inflation models. We find that the second-order Stewart-Lyth calculation gives extremely accurate results, typically better than one percent. We use our code to carry out an expansion about the general power-law inflation solution, providing a fitting function giving results of even higher accuracy.

Andrew R Liddle; Ian J Grivell



[Suprasegmental effects of selective posterior rhizotomy].  


The occurrence of spasticity is most commonly attributed to the lack of presynaptic inhibition. Perinatal damage to the central nervous system, as it happens in cerebral palsy, leads to pathological reflex response both on segmental and polysegmental levels. It results not only in clinical signs typical for spasticity but also in alterations of brainstem function, such as dysarthria or congenital nystagmus. Selective posterior rhizotomy is a neurosurgical method, routinely used in the treatment of spasticity. The lumbosacral posterior roots are partially cut under perioperative neurophysiological control. The aim of the treatment is the reduction of afferentation for posterior horns resulting in a decrease of pathological reflex responses. Selective posterior rhizotomy consequently decreases lower limbs spasticity. The improvement of upper extremities fine skills, the improvement of speech and cognitive functions has been also observed after selective posterior rhizotomy. The possible pathophysiological explanations of these so-called suprasegmental effects are discussed in the article. PMID:15446453

Horínek, D; Tichý, M; Cerný, R; Vlková, J



14 CFR 417.224 - Probability of failure analysis.  

Code of Federal Regulations, 2011 CFR

...probability in a consistent manner. A launch vehicle failure probability estimate must use accurate data, scientific principles, and a method that is statistically or probabilistically valid. For a launch vehicle with fewer than two...



14 CFR 417.224 - Probability of failure analysis.  

Code of Federal Regulations, 2010 CFR

...probability in a consistent manner. A launch vehicle failure probability estimate must use accurate data, scientific principles, and a method that is statistically or probabilistically valid. For a launch vehicle with fewer than two...



14 CFR 417.224 - Probability of failure analysis.  

...probability in a consistent manner. A launch vehicle failure probability estimate must use accurate data, scientific principles, and a method that is statistically or probabilistically valid. For a launch vehicle with fewer than two...



14 CFR 417.224 - Probability of failure analysis.  

Code of Federal Regulations, 2012 CFR

...probability in a consistent manner. A launch vehicle failure probability estimate must use accurate data, scientific principles, and a method that is statistically or probabilistically valid. For a launch vehicle with fewer than two...



14 CFR 417.224 - Probability of failure analysis.  

Code of Federal Regulations, 2013 CFR

...probability in a consistent manner. A launch vehicle failure probability estimate must use accurate data, scientific principles, and a method that is statistically or probabilistically valid. For a launch vehicle with fewer than two...



Estimating the probability of negative events  

Microsoft Academic Search

How well we are attuned to the statistics of our environment is a fundamental question in understanding human behaviour. It seems particularly important to be able to provide accurate assessments of the probability with which negative events occur so as to guide rational choice of preventative actions. One question that arises here is whether or not our probability estimates for

Adam J. L. Harris; Adam Corner; Ulrike Hahn



Late-onset post-irradiation vasculopathy of the posterior cerebral vasculature.  


Radiotherapy is extensively used in the treatment of malignant tumors of the central nervous system, but may also cause considerable morbidity and mortality, probably through damage to the remarkably vulnerable vascular system. We present two cases of infarction in the posterior cerebral vasculature related to earlier irradiation for a pineal gland tumor. Two patients were irradiated for a pineal gland tumor in young adulthood. Respectively 20 and 35 years later, they presented with a progressive neurological decline, related to early progressive atherosclerosis in the posterior cerebral vasculature. In conclusion, irradiation of the posterior cerebral territory may produce precocious atherosclerosis of posterior circulation vasculature, even decades later. When a progressive clinical decline with accumulating ischemic events is observed, together with signs of atherosclerosis, radiotherapy-related vasculopathy may be considered. PMID:22427301

van den Ameele, Jelle; Sieben, Anne; Van den Broecke, Caroline; Boterberg, Tom; Defreyne, Luc; Achten, Eric; Lammens, Martin; Hemelsoet, Dimitri



Data analysis in emission tomography using emission-count posteriors  

NASA Astrophysics Data System (ADS)

A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography.

Sitek, Arkadiusz



Data analysis in emission tomography using emission-count posteriors.  


A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography. PMID:23032513

Sitek, Arkadiusz



[(12)Revascularisation and aneurysms of the posterior circulation].  


This is the last article, namely, the twelfth topic, in the series "personal view and historical backgrounds of operative neurosurgery." In this article, revascularisation and aneurysms of the posterior circulation are thematized. As an example for classic posterior circulation EC-IC bypass, a case of basilar stenosis is presented. The stenosis turned out to occlusion by good patency of the STA-SCA bypass, and although it initially showed clinical improvement, it manifested as severe pontine infarction several months later. Considerations on such malignant conversion are discussed together with probable prevention methods. Other revascularisation methods involving the supracerebellar transtentorial approach(SCTTA), namely, OA-SCA or OA-PCA bypass in the sitting position, are presented and their advantages and disadvantages are discussed. As for posterior circulation aneurysms, the role of SEAC and its advantages for treating basilar bifurcation aneurysms are presented and discussed. SCTTA and SAHE approach are presented as special approaches for other PCA aneurysms, and their advantages of getting the parent artery P2 for P2-P3 junction aneurysm in the latter was emphasized. The advantage of a sitting position for revascularisation or aneurysm surgeries, cleanliness of the operative field in cases of premature rupture or clipping procedure, and through the bush of lower cranial nerves are also discussed. PMID:24698899

Yonekawa, Yasuhiro



Adaptive approximation of higher order posterior statistics  

NASA Astrophysics Data System (ADS)

Filtering is an approach for incorporating observed data into time-evolving systems. Instead of a family of Dirac delta masses that is widely used in Monte Carlo methods, we here use the Wiener chaos expansion for the parametrization of the conditioned probability distribution to solve the nonlinear filtering problem. The Wiener chaos expansion is not the best method for uncertainty propagation without observations. Nevertheless, the projection of the system variables in a fixed polynomial basis spanning the probability space might be a competitive representation in the presence of relatively frequent observations because the Wiener chaos approach not only leads to an accurate and efficient prediction for short time uncertainty quantification, but it also allows to apply several data assimilation methods that can be used to yield a better approximate filtering solution. The aim of the present paper is to investigate this hypothesis. We answer in the affirmative for the (stochastic) Lorenz-63 system based on numerical simulations in which the uncertainty quantification method and the data assimilation method are adaptively selected by whether the dynamics is driven by Brownian motion and the near-Gaussianity of the measure to be updated, respectively.

Lee, Wonjung



Validation of Bayesian posterior distributions using a multidimensional Kolmogorov--Smirnov test  

E-print Network

We extend the Kolmogorov--Smirnov (K-S) test to multiple dimensions by suggesting a $\\mathbb{R}^n \\rightarrow [0,1]$ mapping based on the probability content of the highest probability density region of the reference distribution under consideration; this mapping reduces the problem back to the one-dimensional case to which the standard K-S test may be applied. The universal character of this mapping also allows us to introduce a simple, yet general, method for the validation of Bayesian posterior distributions of any dimensionality. This new approach goes beyond validating software implementations; it provides a sensitive test for all assumptions, explicit or implicit, that underlie the inference. In particular, the method assesses whether the inferred posterior distribution is a truthful representation of the actual constraints on the model parameters. We illustrate our multidimensional K-S test by applying it to a simple two-dimensional Gaussian toy problem, and demonstrate our method for posterior validat...

Harrison, Diana; Carvalho, Pedro; Hobson, Michael



Conditional Probability and Probability of Simultaneous Events  

NSDL National Science Digital Library

This lesson is designed to further students' practice with probability as well as introduce them to conditional probability and probabilities of simultaneous independent events. The lesson provides links to discussions and activities related to conditional and simultaneous probabilities as well as suggested ways to integrate them into the lesson. Finally, this lesson provides links to follow-up lessons designed for use in succession with this one.



MR Findings of Cortical Blindness Following Cerebral Angiography: Is This Entity Related to Posterior Reversible Leukoencephalopathy?  

Microsoft Academic Search

Summary: We describe MR findings in three patients who experienced transient cortical blindness following cerebral angiograms. All angiograms were performed by using the same nonionic contrast medium. On the basis of similar clinical and radiologic findings, we believe that this entity is closely related to and probably has the same pathophys- iology as posterior reversible leukoencephalopathy. Cortical blindness is a

Gaurav Saigal; Rita Bhatia; Sanjiv Bhatia; Ajay K. Wakhloo



Sickle cell disease and posterior reversible leukoencephalopathy.  


Sickle cell disease can present with neurological manifestations. One such presentation is with posterior reversible leukoencephalopathy also known as reversible posterior leukoencephalopathy. The condition is classically described as reversible over time; it commonly presents with oedematous changes involving the white matter of the occipital and parietal regions. Only a few patients with the association between sickle cell disease and posterior reversible leukoencephalopathy have been described in the adult literature. We present two patients from our institutions to emphasise the association between the two conditions and summarise the published cases in the literature. PMID:24656986

Geevasinga, Nimeshan; Cole, Catherine; Herkes, Geoffrey K; Barnett, Yael; Lin, Jamie; Needham, Merrilee



Posterior compartment prolapse: a urogynecology perspective.  


Posterior compartment prolapse is often caused by a defect in the rectovaginal septum, also known as Denonvillier's fascia. Patients with symptomatic posterior compartment prolapse can present with bulge symptoms as well as defecatory dysfunction, including constipation, tenesmus, splinting, and fecal incontinence. The diagnosis can successfully be made on clinical examination. Treatment of posterior prolapse includes pessaries and surgery. Both traditional colporrhaphy and site-specific defect repair have excellent success rates. Complications from surgery can include sexual dysfunction, de novo dyspareunia, and defecatory dysfunction. Compared with native tissue repair, biological and synthetic grafting has not improved overall anatomic and subjective outcomes. PMID:22877719

Richardson, Monica L; Elliot, Christopher S; Sokol, Eric R



Accurate monotone cubic interpolation  

NASA Technical Reports Server (NTRS)

Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.

Huynh, Hung T.



Accurate Finite Difference Algorithms  

NASA Technical Reports Server (NTRS)

Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

Goodrich, John W.



Accurate Unlexicalized Parsing  

Microsoft Academic Search

We demonstrate that an unlexicalized PCFG can parse much more accurately than previously shown, by making use of simple, linguistically motivated state splits, which break down false independence assumptions latent in a vanilla treebank grammar. Indeed, its performance of 86.36% (LP\\/LR F PCFG models, and surprisingly close to the current state-of-the-art. This result has potential uses beyond establishing a strong

Dan Klein; Christopher D. Manning



Passionate About Probability  

NSDL National Science Digital Library

In this probability unit plan, three lessons guide students through the use of probability vocabulary, displaying probability on a number line, writing probability as a fraction, and making predictions based on probability. The unit begins with students learning and applying new vocabulary to the book "Probably Pistachio" by Stuart J. Murphy. In lesson two students use dice, spinners, and real life events to write probability as fractions and make predictions based on these fractions, while still using the probability vocabulary. The third lesson includes another probability experiment and a summative assessment. All student worksheet are included with answer keys in PDF format.

Pearce, Jeanine; Streck, Tracey



Extended Probabilities: Mathematical Foundations  

E-print Network

There are important problems in physics related to the concept of probability. One of these problems is related to negative probabilities used in physics from 1930s. In spite of many demonstrations of usefulness of negative probabilities, physicists looked at them with suspicion trying to avoid this new concept in their theories. The main question that has bothered physicists is mathematical grounding and interpretation of negative probabilities. In this paper, we introduce extended probability as a probability function, which can take both positive and negative values. Defining extended probabilities in an axiomatic way, we show that classical probability is a positive section of extended probability.

Mark Burgin



Practice with Probability  

NSDL National Science Digital Library

This set of probability lesson plans includes a variety of activities that engage students and reinforce the concepts of probability. Through these lessons students play a traditional Native American Stick game, they read Probably Pistachio, by Stuart J. Murphy, and they demonstrate probability with probability bags and dice. Included in this resource is teacher background information, student worksheets (pdf), and extension suggestions.



Anatomical Posterior Cruciate Ligament TransplantationA Biomechanical Analysis  

Microsoft Academic Search

Background: Although current techniques of posterior cruciate ligament reconstruction may successfully stabilize the posterior cruciate ligament-deficient knee, no studies have demonstrated restoration of intact-knee kinematics.Hypothesis: Posterior cruciate ligament transplantation will successfully restore posterior stability and kinematics to the posterior cruciate ligament-deficient knee.Study Design: Controlled laboratory study.Methods: Seven pairs (donor\\/recipient) of size-matched cadaveric knees underwent a novel technique for posterior cruciate

Daniel K. Davis; David H. Goltz; Donald C. Fithian; Darryl D’Lima



Estimating Probabilities from Small Samples Bruno Jedynak, Sanjeev Khudanpur and Ali Yazgan  

E-print Network

Estimating Probabilities from Small Samples Bruno Jedynak, Sanjeev Khudanpur and Ali Yazgan Johns function, the Bayesian estimate 2 ¢ © of ¢ £!¥¨§© is the mean of the posterior probability 5Y¢Vd "48 given heuristics, or from a held out portion of " , to pro- vide nonzero probability to unseen words. Readers in

Jedynak, Bruno M.


Probability 1/e  

ERIC Educational Resources Information Center

Quite a number of interesting problems in probability feature an event with probability equal to 1/e. This article discusses three such problems and attempts to explain why this probability occurs with such frequency.

Koo, Reginald; Jones, Martin L.



Posterior approach white line advancement ptosis repair: the evolving posterior approach to ptosis surgery  

Microsoft Academic Search

IntroductionWe describe a surgical technique for ptosis correction in moderate to good levator function involving advancement of the levator aponeurosis via a transconjunctival posterior approach without resection of Müller's muscle. We present our experience of and the results from this method, and review the evolution of posterior approach ptosis surgery.PurposeTo assess the efficacy and predictability of posterior approach white line

Vikesh Patel; Aysha Salam; Raman Malhotra



Posterior horn instability of the medial meniscus a sign of posterior meniscotibial ligament insufficiency  

Microsoft Academic Search

Purpose  In longstanding chronic anterior cruciate ligament (ACL) insufficiency, we identified an abnormal movement of the posterior\\u000a medial meniscal horn, likely due to insufficiency of the posteromedial meniscotibial ligament. Passing from extension to flexion\\u000a or vice versa, the medial posterior horn slides below the posterior rim of the tibia exposing the tibial plateau. Fixation\\u000a with suture anchors of the meniscotibial ligament

P. P. Mariani



Posterior urethral polyp with type I posterior urethral valves: a rare association in a neonate.  


Urethral polyp is a rare cause of bladder outlet obstruction, voiding dysfunction, and hematuria in the pediatric age group. Urethral polyps are rarely associated with other congenital urinary tract anomalies. In this study, we report a case of solitary posterior urethral polyp with type I posterior urethral valve in a 7-day-old neonate presented with urinary retention and deranged renal function. The polyp was diagnosed on cystoscopy. Transurethral resection of the polyp with posterior urethral valve fulguration was performed. Pathologic assessment revealed a fibroepithelial lesion, which was consistent with congenital posterior urethral polyp. PMID:24767515

Kesan, Krushnakumar V; Gupta, Rahul Kumar; Kothari, Paras; Gupta, Abhaya; Mudkhedkar, Kedar; Kamble, Ravikiran; Dikshit, K Vishesh



Estimating the full posterior pdf with particle filters  

NASA Astrophysics Data System (ADS)

The majority of data assimilation schemes rely on linearity assumptions. However as the resolution and complexity of both the numerical models and observations increases, these linearity assumptions become less appropriate. A need is arising for fully non-linear data assimilation schemes, such as particle filters. Recently, new particle filter schemes have been generated that explore the freedom in proposal densities and that are quite effective in estimating the mean of the posterior probability density function (pdf), even in very high dimensional systems. However, in non-linear data assimilation the solution to the data assimilation problem is the full posterior pdf. At the same time we can only afford a limited number of particles. Here we concentrate on the equivalent weights particle filter in conjunction with a 65,000 dimensional Barotropic Vorticity model. Specifically we test the ability of the scheme to represent the posterior in three important areas. In many actual geophysical applications, observations will be sparse and may well be unevenly distributed. We discuss the effect of changing the frequency, number and distribution of the observed variables on the ensemble representation of the posterior pdf. Specifically we show that the filter has remarkably good convergence in marginal and joint pdfs with ensemble size, and the rank histograms are quite flat, even with low observation numbers and low observation frequencies. Only when the observation frequency is much larger than the typical decorrelation time scale of the system do we see underdispersive ensembles when using 32 particles. The second area attempts to replicate the realistic situation of using a geophysical model designed without a full understanding of the error statistics of the truth. This is done by using deliberately erroneous error statistics in the ensemble equations compared to those used to generate the truth. Specifically we consider changes in the correlation length-scales and variances in the model error statistics. Again the filter is remarkably successful in generating correct posterior pdfs, although rank histograms tend to point to under- or overdispersive ensembles. One of the interesting results is that when we overestimate the model error amplitude the ensemble is underdispersive. We present an explanation for this counter-intuitive phenomenon. Finally we show that the computational effort involved in the equivalent-weights particle filter is comparable to running a simple resampling particle filter with the same number of particles.

Ades, Melanie; van Leeuwen, Peter Jan



A case of fracture of posterior margin of lateral tibial plateau by pivot shift mechanism in chronic ACL insufficiency  

Microsoft Academic Search

We present a case of the fracture of the posterior margin of the lateral tibial plateau, probably by pivot shift mechanism\\u000a in a chronic anterior cruciate ligament (ACL) insufficient knee. Multitudes of direct and indirect signs of ACL injury were\\u000a evident on MRI, including anterior translation of the lateral tibial plateau, buckling of the posterior cruciate ligament,\\u000a deep sulcus sign,

Jae Ho Yoo; Bo Kyu Yang; Ho Kwang Ryu



On differentiating the probability of error in multipopular feature selection  

NASA Technical Reports Server (NTRS)

A method of linear feature selection for n dimensional observation vectors which belong to one of m populations is presented. Each population has a known apriori probability and is described by a known multivariate normal density function. Specifically we consider the problem of finding a k x n matrix B of rank k (k n) for which the transformed probability of misclassification is minimized. Providing that the transformed a posterior probabilities are distinct theoretical results are obtained which, for the case k = l, give rise to a numerically tractable formula for the derivative of the probability of misclassification. It is shown that for the two population problem this condition is also necessary. The dependence of the minimum probability of error on the a priori probabilities is investigated. The minimum probability of error satisfies a uniform Lipschitz condition with respect to the a priori probabilities.

Peters, B. C.



Arthroscopic stabilization of posterior shoulder instability.  


Posterior shoulder instability is a rare and challenging condition with a complex patho-anatomy. The role of arthroscopic repair in the treatment remains poorly defined. The purpose of this study is to evaluate the result of arthroscopic stabilization procedures in patients with posterior shoulder instability. In this case series, we treated eighteen patients (19 shoulders) with posterior shoulder instability with either arthroscopic thermal capsular shrinkage (9 patients), capsulorrhaphy (3) or labral refixation (7). There were eight male and ten female patients with a mean age of 26 years. The study group included unidirectional (6 patients; PI), bi-directional (8; PII) and multidirectional posterior instability (5; MDI). The Rowe-score and DASH-score as well as subjective and objective evaluations of the patients function, range of motion, pain and instability were used as clinical outcome measurements. At a mean follow-up of 50 months, the Rowe-score improved significantly from 46 to 74 (P = 0.005). Four patients (21%) had recurrent instability after arthroscopic treatment (2 with generalized ligamentous laxity; 3 after thermal shrinkage). Analysis of postoperative DASH-scores showed a tendency toward inferior outcomes after thermal shrinkage and in patients with an a-traumatic origin of shoulder instability. We conclude that arthroscopic shoulder stabilization by either labral refixation or capsulorrhaphy is a safe and effective treatment for posterior shoulder instability. Thermal capsular shrinkage however showed poor results and should be abandoned for this indication. PMID:20411378

Engelsma, Y; Willems, W J



A Bayesian Probability Calculus for Density Matrices  

E-print Network

One of the main concepts in quantum physics is a density matrix, which is a symmetric positive definite matrix of trace one. Finite probability distributions are a special case where the density matrix is restricted to be diagonal. Density matrices are mixtures of dyads, where a dyad has the form uu' for any any unit column vector u. These unit vectors are the elementary events of the generalized probability space. Perhaps the simplest case to see that something unusual is going on is the case of uniform density matrix, i.e. 1/n times identity. This matrix assigns probability 1/n to every unit vector, but of course there are infinitely many of them. The new normalization rule thus says that sum of probabilities over any orthonormal basis of directions is one. We develop a probability calculus based on these more general distributions that includes definitions of joints, conditionals and formulas that relate these, i.e. analogs of the theorem of total probability, various Bayes rules for the calculation of posterior density matrices, etc. The resulting calculus parallels the familiar 'classical' probability calculus and always retains the latter as a special case when all matrices are diagonal. Whereas the classical Bayesian methods maintain uncertainty about which model is 'best', the generalization maintains uncertainty about which unit direction has the largest variance. Surprisingly the bounds also generalize: as in the classical setting we bound the negative log likelihood of the data by the negative log likelihood of the MAP estimator.

Manfred K. Warmuth; Dima Kuzmin



Comparison of the Combined Anterior-Posterior Approach versus Posterior-Only Approach in Scoliosis Treatment  

PubMed Central

Study Design This is descriptive analytical study. Purpose The present study aims at comparing treatment results found between the two groups comprising of patients who underwent posterior spinal fusion using thoracic pedicle screws and the ones who underwent combined anterior-posterior method, respectively. Overview of Literature There was controversy about surgical techniques including anterior, posterior, or a combined anterior-posterior approaches are applied to treat non-congenital scoliosis with surgical indications. Methods Medical records of 50 patients suffering from thoracic non-congenital scoliosis with curves exceeding 70° were reviewed. In this study, 25 patients who underwent posterior spinal fusion using thoracic pedicle screws were compared with 25 patients who underwent combined anterior-posterior method. Results Patients treated through posterior-only and combined approaches were respectively hospitalized for 11.84±5.18 and 26.5±5.2 days (p=0.001). There was a significant difference between these two groups considering intensive care unit admission duration (p=0.001), correction in sagittal view of X-ray (p=0.01), and number of days the patients underwent traction (0.001). Finally, coronal view was corrected without any significant difference (p=0.2). Conclusions According to our findings, it is hypothesized that posterior-only method is associated with some significant advantages and is an advisable method in patients with severe scoliosis over than 70°. PMID:24596599

Pourfeizi, Hossein Hojjat; Sales, Jafar Ganjpour; Borran, Ghanbar; Alavi, Sahar



Spinal stenosis and posterior lumbar interbody fusion.  


One hundred forty-two patients with the common types of spinal stenosis were treated by posterior lumbar interbody fusion (PLIF). The majority of the patients had one or more decompressive procedures prior to PLIF. The results were excellent or good in 78%. A review of the literature concerning long-term results of decompressive procedures indicates a short-term failure rate of 15%-20% and about 50% failure by ten or more years after the operation. Anterior fusion in primary disc lesions produces admirable results but is of little value in spinal stenosis. Long-term reports of the success rates of posterior lumbar interbody fusion indicate that this operation combines the success rate of an anterior interbody fusion with the benefits of posterior decompression. PMID:3971609

Hutter, C G



Posterior-compartment repair: a urology perspective.  


The prevalence of posterior-compartment prolapse (rectocele) is not known. The authors have found that operative repair symptomatically improved a majority of patients with impaired defecation associated with a large rectocele, but this improvement was likely related at least in part to factors other than the size of the rectocele. Multiple surgical techniques are available for rectocele repair, and the literature is not clear regarding indications for each type of surgical intervention. This article reviews the literature regarding various types of posterior-compartment repair, and draws conclusions regarding their absolute efficacy and relative efficacy in comparison with one another. PMID:22877720

Gomelsky, Alex; Dmochowski, Roger R



Popliteal Pseudoaneurysm after Arthroscopic Posterior Cruciate Ligament Reconstruction  

PubMed Central

This report presents the case of a 30-year-old motocross (BMX) cyclist with a third-degree posterior cruciate ligament rupture. The technique used for reconstruction was the transtibial single-bundle autologous hamstring technique. Unfortunately, the procedure was complicated by a popliteal pseudoaneurysm, which was located in line with the tibial canal. The pseudoaneurysm was treated with an end-to-end anastomosis and the patient recovered without further complaints. In this case, the popliteal artery was damaged most probably by the edge of the reamer or the guide wire during removal. Vascular complications can be limb- and life-threatening. This case report aims to increase the awareness of this serious complication with a review of the literature. PMID:25229050

Breugem, Stefan J.M.; Driessen, Marcel J.M.



Risk estimation using probability machines  

PubMed Central

Background Logistic regression has been the de facto, and often the only, model used in the description and analysis of relationships between a binary outcome and observed features. It is widely used to obtain the conditional probabilities of the outcome given predictors, as well as predictor effect size estimates using conditional odds ratios. Results We show how statistical learning machines for binary outcomes, provably consistent for the nonparametric regression problem, can be used to provide both consistent conditional probability estimation and conditional effect size estimates. Effect size estimates from learning machines leverage our understanding of counterfactual arguments central to the interpretation of such estimates. We show that, if the data generating model is logistic, we can recover accurate probability predictions and effect size estimates with nearly the same efficiency as a correct logistic model, both for main effects and interactions. We also propose a method using learning machines to scan for possible interaction effects quickly and efficiently. Simulations using random forest probability machines are presented. Conclusions The models we propose make no assumptions about the data structure, and capture the patterns in the data by just specifying the predictors involved and not any particular model structure. So they do not run the same risks of model mis-specification and the resultant estimation biases as a logistic model. This methodology, which we call a “risk machine”, will share properties from the statistical machine that it is derived from. PMID:24581306



Arthroscopic Posterior Bone Block Procedure: A New Technique Using Suture Anchor Fixation  

PubMed Central

We present a novel all-arthroscopic technique of posterior shoulder stabilization that uses suture anchors for both bone block fixation and capsulolabral repair. The bone graft, introduced inside the glenohumeral joint through a cannula, is fixed with 2 suture anchors. The associated posteroinferior capsulolabral repair places the bone block in an extra-articular position. In this article we present the detailed arthroscopic technique performed in a consecutive series of 15 patients and report the early results. We also report the positioning, healing, and remodeling of the bone block using postoperative 3-dimensional computed tomography. The benefits of this new technique are as follows: (1) it is all arthroscopic, preserving the posterior deltoid and posterior rotator cuff muscles; (2) it is accurate, resulting in appropriate bone block positioning; (3) it is efficient, allowing for consistent bone graft healing; (4) it is anatomic, both restoring the glenoid bone stock and repairing the injured posterior labrum; and (5) it is safe, limiting hardware-related complications and eliminating the risk of injury to vital structures associated with drilling or screw insertion from posterior to anterior. We believe that this technique is advantageous because it does not use screws for fixation and may be safer for the patient. PMID:24892011

Boileau, Pascal; Hardy, Marie-Beatrice; McClelland, Walter B.; Thelu, Charles-Edouard; Schwartz, Daniel G.



[Posterior longitudinal ligament ossification: case report].  


Posterior longitudinal ligament ossification of cervical spine is a rare condition among caucasians. A 42 years old japanese patient with progressive walking difficulty was diagnosed with this pathology by CT scan and MRI and treated surgically by an anterior approach with arthrodesis. Pathophysiology, racial prevalence, clinical picture, radiological characteristics and surgical approaches options are revised. PMID:16622577

Tella, Oswaldo Inácio de; Herculano, Marco Antonio; Paiva Neto, Manoel Antonio; Faedo Neto, Atílio; Crosera, João Francisco



Extralobar pulmonary sequestration simulates posterior neurogenic tumor  

Microsoft Academic Search

We report a case of 19-year-old asymptomatic man with posterior mediastinal mass thought to be of neurogenic origin on computed tomography scan. During video-assisted thoracic surgery the mass appeared to be an extralobar pulmonary sequestration. Surgery was straightforward by division of vascular pedicle. Histopathology confirmed diagnosis.

Ryszard W Lupinski; Thirugnanam Agasthian; Chong Hee Lim; Yeow Leng Chua



Vision through nuclear and posterior subcapsular cataract  

Microsoft Academic Search

We have developed a new set of tests for evaluation of visual function through media opacities, based on vernier acuity measurements (hyperacuity). In this paper, results of one of these tests, the ‘gap test’, are compared in patients with posterior subcapsular (PSC) cataract versus nuclear cataract (NC). Patients with PSC cataract often report multiple images or significant ‘star burst’ effects.

Patrizia Baraldi; Jay M. Enoch; Sylvan Raphael



Acute Posterior Ischemic Optic Neuropathy Mimicking Posterior Cerebral Artery Stroke Visualized by 3-Tesla MRI  

PubMed Central

Acute ischemic lesions of the posterior optic nerve and optic tract can produce a variety of visual field defects. A 71-year-old woman presented with acute hemianopia, which led to rt-PA thrombolysis for suspected posterior cerebral artery ischemia. 3-Tesla cMRI, however, revealed the cause to be an acute posterior ischemic optic neuropathy. Cases like this may be more common than thought and quite regularly overlooked in clinical practice, especially when there is no high-resolution MRI available. This case strengthens the importance of repeat MR imaging in patients with persistent visual field defects. PMID:23185170

Menzel, Tilman; Kern, Rolf; Griebe, Martin; Hennerici, Michael; Fatar, Marc



Bayesian Probability Patrick Maher  

E-print Network

choices maxi- mize expected utility. Since expected utility is defined in terms of probability and utility concepts, that is, senses of the word "probability" in ordinary language. There are also philosophical

Fitelson, Branden


Evolution and Probability.  

ERIC Educational Resources Information Center

Some of the most impressive-sounding criticisms of the conventional theory of biological evolution involve probability. Presents a few examples of how probability should and should not be used in discussing evolution. (ASK)

Bailey, David H.



Probability on a Budget.  

ERIC Educational Resources Information Center

Describes how to use common dice numbered 1-6 for simple mathematical situations including probability. Presents a lesson using regular dice and specially marked dice to explore some of the concepts of probability. (KHR)

Ewbank, William A.; Ginther, John L.



Introduction to Probability  

NSDL National Science Digital Library

This resource is designed to introduce students to the concept of probability: the probability of a rare event is represented by a positive number close to zero, the probability of a nearly certain event occurring is represented by a positive number slightly less than one. Students will indicate the approximate probability of events on a number line and determine which events are more likely than others.

Blumsack, Steven



Teachers' Understandings of Probability  

Microsoft Academic Search

Probability is an important idea with a remarkably wide range of applications. However, psychological and instructional studies conducted in the last two decades have consistently documented poor understanding of probability among different populations across different settings. The purpose of this study is to develop a theoretical framework for describing teachers' understandings of probability. To this end, we conducted an 8-day

Yan Liu; Patrick Thompson



Data Analysis & Probability  

NSDL National Science Digital Library

Probability is fun! First, guess the magicians number in Magician Probability! Next, answer the questions on 'which is more likely" in the game Probability comparisons. Then, Help sort our Earth in the sorting game. All you have to do is pick up the trash and sort it into the correct pile. Finally, try pumpkin sorting. Just drag the pumpkins into a sorting ...

Taylor, Ms.



Analytical Probability Distributions  

Microsoft Academic Search

This note introduces four analytical probability distributions and the underlying uncertain processes from which they can be derived. It demonstrates that, when we can build a reasonable model of an uncertain process, we can use the model to derive the probability distribution from fundamental principles and forgo the chore of estimating the distribution subjectively by assessing fractiles. The probability distributions

Dana Clyman


Fundamentals of probability  

NSDL National Science Digital Library

This is a free digital textbook on probability theory. It is ideal for a second-year undergraduate course in probability theory. It aims to fill the gap between elementary treatments of probability theory and more advanced treatments based on measure theory.

Taboga, Marco



-Divergence Continuous Probability Distributions  

E-print Network

of the minimum 2 -divergence probability distributions. Key Words: Divergence measure, Chi square divergence-entropy principle of Kullback(1959) is: "When a prior probability density function of X , gx, which estimates principle as: "When a prior probability density function of X , gx, which estimates the underlying

Bolch, Tobias


Dependent Probability Spaces  

ERIC Educational Resources Information Center

The mathematical model used to describe independence between two events in probability has a non-intuitive consequence called dependent spaces. The paper begins with a very brief history of the development of probability, then defines dependent spaces, and reviews what is known about finite spaces with uniform probability. The study of finite…

Edwards, William F.; Shiflett, Ray C.; Shultz, Harris



Arthroscopic Posterior Labral Repair and Capsular Shift With a Lateralized Posterior Portal  

PubMed Central

Arthroscopic techniques for posterior shoulder subluxation with labral injuries in athletes have shown good results. The difficulty with the procedure is gaining appropriate access to the posteroinferior quadrant of the glenoid at a steep enough angle that allows for safe anchor placement. Various portals have been described that can be used as accessory portals for anchor placement. Although the use of additional portals to create appropriate access to the joint is always encouraged, preoperative planning can minimize the need for their use. The video shows a simple technique for posterior labral repair with capsular plications through a lateralized posterior portal in the lateral decubitus position. This technique allows the surgeon to address posterior labral tears and capsular laxity without the need for accessory portals. PMID:24400175

Ciccone, William J.



Boundary Crossing Probabilities for Locally Poisson Processes  

Microsoft Academic Search

We derive large deviation approximations to boundary crossing probabilities for a class of point processes which can be approximated locally as Poisson processes. In the special case of empirical processes, we are able to obtain second order correction terms. The methods are applied to Kolmogorov-Smirnov testing, where we are able to obtain accurate approximations to the significance level when the

Clive R. Loader



Bayesian model selection using exact and approximated posterior probabilities with applications to Star Data  

E-print Network

&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by: Jeffrey D. Hart (Chair of Committee) James A. Calvin (Member) Marina Vannucci (Member) Douglas A. Hensley (Member) Michael T...&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by: Jeffrey D. Hart (Chair of Committee) James A. Calvin (Member) Marina Vannucci (Member) Douglas A. Hensley (Member) Michael T...

Pokta, Suriani



A model for equine breed identification using microsatellites and posterior probability testing  

E-print Network

products were analyzed by polyacrylantide gel electrophoresis followed by autoradiography. Segregation analysis of the 19 n-microsatellite loci did not indicate linkage (Z > 3.0) between any of the loci. Microsatellite allele distributions in the unrelated...

Chastain, Pepper Alise




E-print Network

of polymerase chain reaction. Probabilistic models of polymerase chain reactions were proposed and studied and Sagitov (2002). In models of polymerase chain reactions and in similar contexts, the initial pop- ulation processes; Bayesian estimation; Polymerase chain reac- tions 2000 Mathematics Subject Classification

Paris-Sud XI, Université de


Applied Probability Trust (11 March 2008) ASYMPTOTICS OF POSTERIORS FOR BINARY BRANCHING  

E-print Network

of polymerase chain reaction. Probabilistic models of polymerase chain reactions were proposed and studied and Sagitov (2002). In models of polymerase chain reactions and in similar contexts, the initial pop- ulation processes; Bayesian estimation; Polymerase chain reac- tions 2000 Mathematics Subject Classification

Paris-Sud XI, Université de


Elementary Probability () Elementary Probability 1 / 18  

E-print Network

was conducted in a representative sample of adult males in New York city of all ages and occupations. Mr F Probability 3 / 18 #12;Hypothetical medical experiment A new pharmaceutical treatment for depression A new pharmaceutical treatment for depression is discovered According to theory, the treatment should

Busemeyer, Jerome R.


In All Probability, Probability is not All  

ERIC Educational Resources Information Center

The national lottery is often portrayed as a game of pure chance with no room for strategy. This misperception seems to stem from the application of probability instead of expectancy considerations, and can be utilized to introduce the statistical concept of expectation.

Helman, Danny



Pseudoexfoliation material on posterior chamber intraocular lenses  

PubMed Central

The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL) is a rare finding. We report a series of seven cases with different patterns of pseudoexfoliation material deposition on the posterior chamber IOLs, recognized 2–20 years after cataract surgery. Six patients had an IOL implanted in the capsular bag and one in the ciliary sulcus. Two patients had undergone posterior capsulotomy. Although the pathophysiological mechanisms and clinical significance of this finding remain unknown, the careful follow-up of pseudophakic patients with known or suspected pseudoexfoliation syndrome is essential to monitor the development or progression of glaucoma, since deposition of pseudoexfoliation material continues even after cataract surgery. PMID:25143707

da Rocha-Bastos, Ricardo António; Silva, Sérgio Estrela; Prézia, Flávio; Falcão-Reis, Fernando; Melo, António B



Posterior reversible encephalopathy syndrome following measles vaccination.  


Due to recent domestic measles outbreaks in Japan, the Japanese government has mandated measles vaccination at ages 14 and 17 since April 2008. Since then, the number of people receiving measles vaccination has increased in Japan. Measles vaccination may cause serious neurological complications including encephalopathy, although the incidence is very low. We report here an adult case of posterior reversible encephalopathy syndrome (PRES) and myeloradiculoneuropathy following measles vaccination. Brain MRI demonstrated typical findings of PRES, high intensity signals in the occipital lobes on FLAIR imaging, isointensity signals on diffusion weighted imaging, with an increase in the apparent diffusion coefficient (ADC). Vasoconstriction mainly in the posterior cerebral arteries was detected by MRA. Physicians should keep in mind the possible occurrence of PRES and myeloradiculoneuropathy following measles vaccination. PMID:20850135

Hamano, Tadanori; Takeda, Tomoko; Morita, Hiroshi; Muramatsu, Tomoko; Yoneda, Makoto; Kimura, Hirohiko; Kuriyama, Masaru



Shining a light on posterior cortical atrophy.  


Posterior cortical atrophy (PCA) is a clinicoradiologic syndrome characterized by progressive decline in visual processing skills, relatively intact memory and language in the early stages, and atrophy of posterior brain regions. Misdiagnosis of PCA is common, owing not only to its relative rarity and unusual and variable presentation, but also because patients frequently first seek the opinion of an ophthalmologist, who may note normal eye examinations by their usual tests but may not appreciate cortical brain dysfunction. Seeking to raise awareness of the disease, stimulate research, and promote collaboration, a multidisciplinary group of PCA research clinicians formed an international working party, which had its first face-to-face meeting on July 13, 2012 in Vancouver, Canada, prior to the Alzheimer's Association International Conference. PMID:23274153

Crutch, Sebastian J; Schott, Jonathan M; Rabinovici, Gil D; Boeve, Bradley F; Cappa, Stefano F; Dickerson, Bradford C; Dubois, Bruno; Graff-Radford, Neill R; Krolak-Salmon, Pierre; Lehmann, Manja; Mendez, Mario F; Pijnenburg, Yolande; Ryan, Natalie S; Scheltens, Philip; Shakespeare, Tim; Tang-Wai, David F; van der Flier, Wiesje M; Bain, Lisa; Carrillo, Maria C; Fox, Nick C



The posterior palatal seal. A review.  


The posterior palatal seal area is described and its anatomical borders are defined. The methods used to achieve a seal are (1) scraping the cast, (2) a selective loading impression technique, and (3) a physiological impression technique. Each method is described and its problems are discussed. It is believed by the authors that the physiological impression technique using wax requires the least amount of skill and experience to master competently. PMID:7004416

Ettinger, R L; Scandrett, F R



Cyclosporine-related reversible posterior leukoencephalopathy: MRI  

Microsoft Academic Search

Three patients aged 48, 11 and 40 years, two of whom were recent recipients of renal transplants and one of a bone marrow\\u000a transplant, developed seizures, with cortical blindness in two cases. All were immunosuppressed with cyclosporine and were\\u000a hypertensive at the onset of symptoms. MRI showed predominantly posterior signal changes in all three cases. The abnormalities\\u000a were more conspicuous

J. M. Jarosz; D. C. Howlett; T. C. S. Cox; J. B. Bingham



Indocyanine green angiography in posterior uveitis  

PubMed Central

Literature review for indocyanine green angiography and evaluate the role of indocyanine green angiogram (ICGA) in patients with posterior uveitis seen at a tertiary referral eye care centre. Detailed review of the literature on ICGA was performed. Retrospective review of medical records of patients with posterior uveitis and dual fundus and ICGA was done after institutional board approval. Eighteen patients (26 eyes) had serpiginous choroiditis out of which 12 patients had active choroiditis and six patients had healed choroiditis, six patients (12 eyes) had ampiginous choroiditis, six patients (12 eyes) had acute multifocal posterior placoid pigment epitheliopathy, eight patients (10 eyes) had multifocal choroiditis, four patients (eight eyes) had presumed ocular histoplasmosis syndrome, four patients (eight eyes) had presumed tuberculous choroiditis, two patients (four eyes) had multiple evanescent white dot syndrome and two patients (four eyes) had Vogt Koyanagi Harada (VKH) syndrome. The most characteristic feature noted on ICGA was the presence of different patterns of hypofluorescent dark spots, which were present at different stages of the angiogram. ICGA provides the clinician with a powerful adjunctive tool in choroidal inflammatory disorders. It is not meant to replace already proven modalities such as the fluorescein angiography, but it can provide additional information that is useful in establishing a more definitive diagnosis in inflammatory chorioretinal diseases associated with multiple spots. It still needs to be determined if ICGA can prove to be a follow up parameter to evaluate disease progression. PMID:23685486

Agrawal, Rupesh V; Biswas, Jyotirmay; Gunasekaran, Dinesh



Treatment of posterior skull base tumors.  


Surgery for posterior skull base tumors may be associated with high morbidity and mortality because of the complex anatomy, irregular bony topography, and vital neurovascular structures in this region. We experienced three benign posterior skull base tumors. These were petroclival and foramen magnum meningiomas and a jugular formen neurinoma. Three dimensional computed tomography (3 D-CT) in addition to the conventional CT, magnetic resonance imaging (MRI), and cerebral angiography were performed preoperatively. Preoperative embolizations for the tumors were also done, and intraoperative neurophysiological monitorings were performed. The tumors could be subtotally removed with no damage to the brainstem, cranial nerves, and vessels. No newly developed postoperative neurological symptoms were observed. As to the remaining tumors, gamma knife (gamma-knife) therapy was planned. 3 D-CT was very useful in the preoperative evaluation of the surgical approach, and the intraoperative neurophysiological monitoring was considered to be necessary to prevent permanent damage. gamma-knife after direct approach was recommended for the benign posterior skull base tumors. PMID:9755601

Lin, C; Node, Y; Teramoto, A



Anterior canal BPPV and apogeotropic posterior canal BPPV: two rare forms of vertical canalolithiasis.  


Posterior canal benign paroxysmal positional vertigo (BPPV) is the most frequent form of BPPV. It is characterized by a paroxysmal positioning nystagmus evoked through Dix-Hallpike and Semont positioning tests. Anterior canal BPPV (AC) is more rare than posterior canal BPPV; it presents a prevalent down beating positioning nystagmus, with a torsional component clockwise for the left canal, counterclockwise for the right canal. Due to the possible lack of the torsional component, it is sometimes difficult to identify the affected ear. An apogeotropic variant of posterior BPPV (APC) has recently been described, characterised by a paroxysmal positional nystagmus in the opposite direction to the one evoked in posterior canal BPPV: the linear component is down-beating, the torsional component is clockwise for the right canal, counter-clockwise for the left canal, so that a contra-lateral anterior canal BPPV could be simulated. During a 16 month period, of 934 BPPV patients observed, the authors identified 23 (2.5%) cases of apogeotropic posterior canal BPPV and 11 (1.2%) cases of anterior canal BPPV, diagnosed using the specific oculomotor patterns described in the literature. Anterior canal BPPV was treated with the repositioning manoeuvre proposed by Yacovino, which does not require identification of the affected side, whereas apogeotropic posterior canal BPPV was treated with the Quick Liberatory Rotation manoeuvre for the typical posterior canal BPPV, since in the Dix-Hallpike position otoliths are in the same position if they come either from the ampullary arm or from the non-ampullary arm. The direct resolution of BPPV (one step therapy) was obtained in 12/34 patients, 8/23 patients with APC and 4/11 patients with AC; canalar conversion into typical posterior canal BPPV, later treated through Quick Liberatory Rotation (two-step therapy), was obtained in 19 patients,14/23 with APC and 5/11 with AC. Three patients were lost to follow-up. Considering the effects of therapeutic manoeuvres, the authors propose a grading system for diagnosis of AC and APC: "certain" when a canalar conversion in ipsilateral typical posterior canal BPPV is obtained; "probable" when APC or AC are directly resolved; "possible" when disease is not resolved and cerebral neuroimaging is negative for neurological diseases. Our results show that the oculomotor patterns proposed in the literature are effective in diagnosing APC and AC, and that APC is more frequent than AC. Both of these rare forms of vertical canal BPPV can be treated effectively with liberatory manoeuvres. PMID:24882928

Califano, L; Salafia, F; Mazzone, S; Melillo, M G; Califano, M



Electrocardiographic diagnosis of remote posterior wall myocardial infarction using unipolar posterior lead V9  

SciTech Connect

The accuracy of four electrocardiographic criteria for diagnosing remote posterior myocardial infarction was assessed prospectively in 369 patients undergoing exercise treadmill testing with thallium scintigraphy. Criteria included the following: (1) R-wave width greater than or equal to 0.04 s and R-wave greater than or equal to S-wave in V1; (2) R-wave greater than or equal to S-wave in V2; (3) T-wave voltage in V2 minus V6 greater than or equal to 0.38 mV (T-wave index); (4) Q-wave greater than or equal to 0.04 s in left paraspinal lead V9. Twenty-seven patients (7.3 percent) met thallium criteria for posterior myocardial infarction, defined as a persistent perfusion defect in the posterobase of the left ventricle. Sensitivities for the four criteria ranged from 4 to 56 percent, and specificities ranged from 64 to 99 percent. Posterior paraspinal lead V9 provided the best overall predictive accuracy (94 percent), positive predictive value (58 percent), and ability to differentiate patients with and without posterior myocardial infarction of any single criterion (p less than .0001). Combining the T-wave index with lead V9 further enhanced the diagnostic yield: the sensitivity for detecting posterior infarction by at least one of these criteria was 78 percent, and when both criteria were positive, specificity was 98.5 percent. It is concluded that a single, unipolar posterior lead in the V9 position is superior to standard 12-lead electrocardiographic criteria in diagnosing remote posterior myocardial infarction, and that combining V9 with the T-wave index maximizes the diagnostic yield.

Rich, M.W.; Imburgia, M.; King, T.R.; Fischer, K.C.; Kovach, K.L. (Jewish Hospital Washington University Medical Center, St. Louis (USA))



Earthquake Probability Mapping  

NSDL National Science Digital Library

This mapping tool allows users to generate Earthquake Probability Maps (EPMs) for a region within 50 kilometers of a location specified by latitude and longitude or by ZIP code. The maps are color-coded; higher earthquake probabilities are indicated by orange and red colors, while lower probabilities are indicated by green or blue. Fault traces are marked in white; rivers are in blue. The maps are also produced in downloadable, printable format (PDF).



Earthquake Probability Mapping  

NSDL National Science Digital Library

This mapping tool allows users to generate Earthquake Probability Maps (EPMs) for a region within 50 kilometers of a location specified by latitude and longitude or by ZIP code. The maps are color-coded; higher earthquake probabilities are indicated by orange and red colors, while lower probabilities are indicated by green or blue. Fault traces are marked in white; rivers are in blue. The maps are also produced in downloadable, printable format (PDF).


Statistics and Probability Tutorial  

NSDL National Science Digital Library

This tutorial, created by Harvey Berman of Stat Trek, provides a basic introduction to many topics in statistics and probability. Topics include: sets and subsets, statistical experiments, counting, basic probability rules, Bayes' theorem, probability distributions, discrete versus continuous, binomial, negative binomial, hypergeometric, multinomial, Poisson, normal, sampling theory, central tendency, variability, sampling distributions, t-distribution, Chi-square distribution, F-distribution, estimation problems, hypothesis testing, power, survey sampling, simple random samples, stratified samples, cluster samples, sample size. This is a general overview of statistics and probability. It is geared towards a high school advanced placement level.

Berman, Harvey



A study of posterior palatal seals with varying palatal forms.  


A study was carried out to determine the depth and width of posterior palatal seals in different shapes of palates. Four different methods of developing the posterior palatal seal were utilized on each patient. The width of the posterior palatal seal area was compared with original models which were produced by plaster impressions. PMID:1104808

Nikoukari, H



Rat posterior parietal cortex: topography of corticocortical and thalamic connections  

Microsoft Academic Search

Anatomical and functional findings support the contention that there is a distinct posterior parietal cortical area (PPC) in the rat, situated between the rostrally adjacent hindlimb sensorimotor area and the caudally adjacent secondary visual areas. The PPC is distinguished from these areas by receiving thalamic afferents from the lateral dorsal (LD), lateral posterior (LP), and posterior (Po) nuclei, in the

R. L. Reep; H. C. Chandler; V. King; J. V. Corwin



Guessing the Probability!  

NSDL National Science Digital Library

Can YOU figure out the probability? Take a pick! Try to Guess the Number in as few tries as possible! There are so many possibilities!! Try to figure out all the possible disguises!! Help the fish, and find out the Probability! ...

Johnson, Ms.



Probability An Introduction with  

E-print Network

or decision analysis. It has been used in this fashion in the industrial engineering department, intersection, and complement. In my view, this is how experienced users of probability think. (For example in this text.) The goal is to move students more quickly towards examples of how probability is really used

Hazen, Gordon


Minimax Probability Machine  

Microsoft Academic Search

When constructing a classier, the probability of correct classi-cation of future data points should be maximized. In the currentpaper this desideratum is translated in a very direct way into anoptimization problem, which is solved using methods from convexoptimization. We also show how to exploit Mercer kernels inthis setting to obtain nonlinear decision boundaries. A worst-casebound on the probability of misclassication

Gert R. G. Lanckriet; Laurent El Ghaoui; Chiranjib Bhattacharyya; Michael I. Jordan



Bayes' Theorem: Conditional Probabilities  

NSDL National Science Digital Library

To perform calculations using Bayes' theorem, enter the probability for one or the other of the items in each of the following pairs (the remaining item in each pair will be calculated automatically). A probability value can be entered as either a decimal fraction such as .25 or a common fraction such as 1/4

Lowry, Richard



Extrapolating human probability judgment  

Microsoft Academic Search

We advance a model of human probability judgment and apply it to the design of an extrapolation algorithm. Such an algorithm examines a person's judgment about the likelihood of various statements and is then able to predict the same person's judgments about new statements. The algorithm is tested against judgments produced by thirty undergraduates asked to assign probabilities to statements

Daniel Osherson; Edward E. Smith; Tracy S. Myers; Eldar Shafir; Michael Stob



Constructive Artificial Intelligence Probability  

E-print Network

referenced. Constructive Artificial Intelligence #12;Probabilities Motivation History: theory of gamblingConstructive Artificial Intelligence Probability Daniel Polani School of Computer Science Intelligence #12;Scenario Dice Game Assume: A die is thrown. Possible outcomes are 1,2. . . 6. How much should

Polani, Daniel


Binomial Probability Model  

NSDL National Science Digital Library

This resource, created by the statistics departed at Western Michigan University, helps define and explain binomial probability. It includes examples and exercises for the learner which facilitate further understanding of the subject. Overall, this specific site is perfect for users studying statistics, more specifically probability testing.

Abebe, Asheber; Daniels, John E.; Kapenga, J. A.; Mckean, Joe W.



Probability and Geometry (elementary)  

NSDL National Science Digital Library

This lesson is designed to introduce students to geometric probability and fairness. This lesson provides links to discussions and activities related to geometric probability as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.



Accurate determination of inflationary perturbations  

E-print Network

We use a numerical code for accurate computation of the amplitude of linear density perturbations and gravitational waves generated by single-field inflation models to study the accuracy of existing analytic results based on the slow-roll approximation. We use our code to calculate the coefficient of an expansion about the exact analytic result for power-law inflation; this generates a fitting function which can be applied to all inflationary models to obtain extremely accurate results. In the appropriate limit our results confirm the Stewart--Lyth analytic second-order calculation, and we find that their results are very accurate for inflationary models favoured by current observational constraints.

Ian J Grivell; Andrew R Liddle



Distortions of the posterior surface in optical coherence tomography images of the isolated crystalline lens: effect of the lens index gradient  

PubMed Central

We quantify the posterior surface distortions in optical coherence tomography (OCT) images of isolated crystalline lenses. The posterior radius of curvature and asphericity obtained from OCT images acquired with the beam incident first on the anterior, and then the posterior, surface were compared. The results were compared with predictions of a ray-tracing model which includes the index gradient. The results show that the error in the radius of curvature is within the measurement reproducibility and that it can be corrected by assuming a uniform refractive index. However, accurate asphericity values require a correction algorithm that takes into account the gradient. PMID:21258553

Borja, David; Siedlecki, Damian; de Castro, Alberto; Uhlhorn, Stephen; Ortiz, Sergio; Arrieta, Esdras; Parel, Jean-Marie; Marcos, Susana; Manns, Fabrice



Dexmedetomidine sedation in painful posterior segment surgery  

PubMed Central

Purpose To present a case series on the use of dexmedetomidine (Precedex) sedation in painful posterior segment surgery performed under topical anesthesia, similar to its use in cataract surgery. Methods A prospective review of cases that had posterior segment surgery under topical anesthesia and that needed sedation. Dexmedetomidine-loading infusion was 1 mcg/kg over 10 minutes, followed by a maintenance infusion (0.5 mcg/kg/h). Results Nine patients were operated on under topical anesthesia: two scleral buckle, five cryopexy, one scleral laceration, and one pars plana vitrectomy with very dense laser therapy in an albinotic fundus; six patients had retinal detachment. General or local anesthesia were not possible due to medical or ocular morbidities, use of anticoagulants, or the surgery plan changed intraoperatively when new pathologies were discovered. The surgeon achieved good surgical control in eight of nine cases, with one patient having ocular and bodily movements that were disturbing. Six patients had no pain, while three patients reported mild pain. No adverse effects were noted and all patients had successful surgical outcomes. Heart rate, blood pressure, and oxygen saturation were well controlled throughout the procedures. The most frequent adverse reactions of dexmedetomidine reported in the literature in less than 5% (hypotension, bradycardia, and dry mouth) were not recorded in the present study. Conclusion When a surgeon has planned to do a pars plana vitrectomy under topical anesthesia and the surgical situation dictates the addition of cryopexy, scleral buckle, or intense laser retinopexy, then sedation with dexmedetomidine can help in the control of ocular pain in the majority of cases, with good intraoperative and immediate postoperative hemodynamic control with the possibility of supplemental rescue analgesia. Dexmedetomidine, a sedative analgesic, is devoid of respiratory depressant effects, and its use in posterior segment surgery under topical anesthesia is reported here for the first time. PMID:23271889

Mansour, Ahmad; Taha, Samar



Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis.  


Cystic or cyst-like malformations of the posterior fossa represent a spectrum of disorders, including the Dandy-Walker malformation, vermian-cerebellar hypoplasia, mega cisterna magna, and arachnoid cyst. Differentiation of these lesions may be difficult with routine cross-sectional imaging; however, an accurate diagnosis is essential for proper treatment planning and genetic counseling. Dandy-Walker malformation is easily diagnosed on the basis of the classic triad: complete or partial agenesis of the vermis, cystic dilatation of the fourth ventricle, and enlarged posterior fossa. Vermian-cerebellar hypoplasia is a general classification that describes congenital malformations with a normal-sized posterior fossa, varying degrees of vermian and cerebellar hypoplasia, and a prominent retrocerebellar cerebrospinal fluid space that communicates freely with a normal or dilated fourth ventricle. Mega cisterna magna can be asymmetric and can manifest apparent mass effect, simulating the appearance of an arachnoid cyst; therefore, ventriculography or cisternography may be needed to demonstrate communication of the cystic mass with the subarachnoid space. A careful review of the embryologic development is essential in understanding these malformations and in making a more accurate radiologic diagnosis. PMID:8031352

Kollias, S S; Ball, W S; Prenger, E C



Posterior optic buttonholing prevents intraocular pressure peaks after cataract surgery with primary posterior capsulorhexis  

Microsoft Academic Search

Background  The performance of a primary posterior capsulorhexis (PPC) with and without posterior optic buttonholing (POBH) may significantly\\u000a influence the intraocular pressure (IOP) after cataract surgery in age-related cataract patients.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The prospective randomized clinical study was performed at the department of Ophthalmology, Medical University of Vienna,\\u000a Austria. Thirty consecutive cataract patients with bilateral same-day cataract surgery (60 eyes) under topical anesthesia

Eva Stifter; Rupert Menapace; Katharina Kriechbaum; Alexandra Luksch



Endoscopic treatment of posterior ankle pain  

Microsoft Academic Search

Purpose  The aim of this study is to describe the indications for two-portal hindfoot endoscopy in the treatment of posterior ankle\\u000a compartment pathologies and to express the effectiveness of this technique by short- to mid-term outcomes on 59 consecutive\\u000a patients.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  In our institute, between 2003 and 2009, patients operated by single surgeon with hindfoot endoscopy were enrolled. The American\\u000a Orthopaedic Foot

Tahir Ogut; Egemen Ayhan; Kaan Irgit; Abdullah Ilker Sarikaya



A Short History of Posterior Dynamic Stabilization  

PubMed Central

Interspinous spacers were developed to treat local deformities such as degenerative spondylolisthesis. To treat patients with chronic instability, posterior pedicle fixation and rod-based dynamic stabilization systems were developed as alternatives to fusion surgeries. Dynamic stabilization is the future of spinal surgery, and in the near future, we will be able to see the development of new devices and surgical techniques to stabilize the spine. It is important to follow the development of these technologies and to gain experience using them. In this paper, we review the literature and discuss the dynamic systems, both past and present, used in the market to treat lumbar degeneration. PMID:23326674

Gomleksiz, Cengiz; Sasani, Mehdi; Oktenoglu, Tunc; Ozer, Ali Fahir



Accurate Evaluation of Quantum Integrals  

NASA Technical Reports Server (NTRS)

Combining an appropriate finite difference method with Richardson's extrapolation results in a simple, highly accurate numerical method for solving a Schrodinger's equation. Important results are that error estimates are provided, and that one can extrapolate expectation values rather than the wavefunctions to obtain highly accurate expectation values. We discuss the eigenvalues, the error growth in repeated Richardson's extrapolation, and show that the expectation values calculated on a crude mesh can be extrapolated to obtain expectation values of high accuracy.

Galant, D. C.; Goorvitch, D.; Witteborn, Fred C. (Technical Monitor)



Experimental Probability in Elementary School  

ERIC Educational Resources Information Center

Concepts in probability can be more readily understood if students are first exposed to probability via experiment. Performing probability experiments encourages students to develop understandings of probability grounded in real events, as opposed to merely computing answers based on formulae.

Andrew, Lane



GASP: a new Genetic Algorithm (based on) Surviving Probability  

Microsoft Academic Search

A. Carvajal-Rodríguez , GASP : a new Genetic Algorithm (based on) Surviving Probability . Online Journal of Bioinformatics 5:23-31, 2004. A new basic genetic algorithm, called GASP (Genetic Algorithm Surviving Probability) is described. The algorithm differs in some essential properties compared to other genetic algorithms (GA's) and is more accurate than traditional GA's in solving some general problems. In GASP

A. Carvajal-Rodríguez


Sampling Networks from Their Posterior Predictive Distribution  

PubMed Central

Recent research indicates that knowledge about social networks can be leveraged to increase efficiency of interventions (Valente, 2012). However, in many settings, there exists considerable uncertainty regarding the structure of the network. This can render the estimation of potential effects of network-based interventions difficult, as providing appropriate guidance to select interventions often requires a representation of the whole network. In order to make use of the network property estimates to simulate the effect of interventions, it may be beneficial to sample networks from an estimated posterior predictive distribution, which can be specified using a wide range of models. Sampling networks from a posterior predictive distribution of network properties ensures that the uncertainty about network property parameters is adequately captured. The tendency for relationships among network properties to exhibit sharp thresholds has important implications for understanding global network topology in the presence of uncertainty; therefore, it is essential to account for uncertainty. We provide detail needed to sample networks for the specific network properties of degree distribution, mixing frequency, and clustering. Our methods to generate networks are demonstrated using simulated data and data from the National Longitudinal Study of Adolescent Health. PMID:25339990

Goyal, Ravi; De Gruttola, Victor; Blitzstein, Joseph



Posterior consistency in conditional distribution estimation  

PubMed Central

A wide variety of priors have been proposed for nonparametric Bayesian estimation of conditional distributions, and there is a clear need for theorems providing conditions on the prior for large support, as well as posterior consistency. Estimation of an uncountable collection of conditional distributions across different regions of the predictor space is a challenging problem, which differs in some important ways from density and mean regression estimation problems. Defining various topologies on the space of conditional distributions, we provide sufficient conditions for posterior consistency focusing on a broad class of priors formulated as predictor-dependent mixtures of Gaussian kernels. This theory is illustrated by showing that the conditions are satisfied for a class of generalized stick-breaking process mixtures in which the stick-breaking lengths are monotone, differentiable functions of a continuous stochastic process. We also provide a set of sufficient conditions for the case where stick-breaking lengths are predictor independent, such as those arising from a fixed Dirichlet process prior. PMID:25067858

Pati, Debdeep; Dunson, David B.; Tokdar, Surya T.



Selective Management of Posterior Stab Wounds  

PubMed Central

Selective management of 473 patients with stab wounds limited to the posterior abdomen was reviewed. This group was composed of predominantly young, healthy men. Laporotomy was based primarily on clinical findings. Tenderness, not localized to the area of injury, or absent or rare bowel sounds best identified patients with serious injuries. Omental protrusion was frequently associated with significant organ injury. Peritoneal lavage and local wound exploration were used infrequently. All patients with fatal injuries were operated on or died within four hours of admission. Diagnosis was delayed in five serious injuries: one diaphragmatic, three retroperitoneal colon perforations and one duodenal injury, all of which were identified and treated successfully in the initial hospital admission without any complications. Seventy-six percent of the patients never required surgery. Sixteen percent of all patients had significant organ injury, and six percent had “nonessential” laporotomy. Overall morbidity was 12 percent and mortality was 1.1 percent. The colon, liver, diaphragm, and kidneys were the most common organs injured. Thus, clinical assessment alone is a reliable means of selectively managing patients with posterior abdominal stab wounds. PMID:3573058

Ocampo, H.; Yamaguchi, M.; Mackabee, J.; Ordog, G.; Fleming, A.



Probability with Roulette  

ERIC Educational Resources Information Center

This article describes how roulette can be used to teach basic concepts of probability. Various bets are used to illustrate the computation of expected value. A betting system shows variations in patterns that often appear in random events.

Marshall, Jennings B.



Guide star probabilities  

NASA Technical Reports Server (NTRS)

Probabilities are calculated for acquiring suitable guide stars (GS) with the fine guidance system (FGS) of the space telescope. A number of the considerations and techniques described are also relevant for other space astronomy missions. The constraints of the FGS are reviewed. The available data on bright star densities are summarized and a previous error in the literature is corrected. Separate analytic and Monte Carlo calculations of the probabilities are described. A simulation of space telescope pointing is carried out using the Weistrop north galactic pole catalog of bright stars. Sufficient information is presented so that the probabilities of acquisition can be estimated as a function of position in the sky. The probability of acquiring suitable guide stars is greatly increased if the FGS can allow an appreciable difference between the (bright) primary GS limiting magnitude and the (fainter) secondary GS limiting magnitude.

Soneira, R. M.; Bahcall, J. N.



Rock, Paper, Scissors Probability!  

NSDL National Science Digital Library

Students learn about probability through a LEGO® MINDSTORMS® NTX-based activity that simulates a game of "rock-paper-scissors." The LEGO robot mimics the outcome of random game scenarios in order to help students gain a better understanding of events that follow real-life random phenomenon, such as bridge failures, weather forecasts and automobile accidents. Students learn to connect keywords such as certainty, probable, unlikely and impossibility to real-world engineering applications.

AMPS GK-12 Program,


Replacement and Probability  

NSDL National Science Digital Library

This lesson is designed to develop students' understanding of sampling with and without replacement and its effects on the probability of drawing a desired object. The lesson provides links to discussions and activities related to replacement and probability as well as suggested ways to work them into the lesson. Finally, the lesson provides links to follow-up lessons that are designed to be used in succession with the current one.



The Probability Factor  

NSDL National Science Digital Library

In this activity, students learn that probability is a way of measuring the chance of something happening. Students make predictions and match predictions with data, using a "probability tester" made from two golf tees. The activity includes a student data sheet. The resource is part of the teacher's guide accompanying the video, NASA SCI Files: The Case of the Phenomenal Weather. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.


Comparison of posterior dynamic and posterior rigid transpedicular stabilization with fusion to treat degenerative spondylolisthesis.  


This article describes the clinical and radiological outcomes of a comparison of posterior dynamic transpedicular stabilization and posterior rigid transpedicular stabilization with fusion after decompression in the treatment of degenerative spondylolisthesis. This prospective clinical and radiologic study was conducted between 2004 and 2007 and included 46 patients, of whom 33 were women (71.7%) and 13 were men (28.3%). Mean patient age was 61.67+/-10.80 years (range, 45-89 years). Twenty-six patients who underwent lumbar decompression and posterior dynamic transpedicular stabilization were followed for a mean of 38 months (range, 24-55 months). In the fusion group, 20 patients who underwent lumbar decompression and rigid stabilization with fusion were followed for a mean of 44 months (range, 26-64 months). The intervertebral space measurements of the dynamic group at the preoperative examination and at 12 and 24 months postoperatively were statistically significantly higher than the intervertebral space measurements of the fusion group (P<.05). In the dynamic group, complications occurred in 2 patients; the first was a screw malposition, which was improved with revision surgery within 1 month of the initial surgery, and the second was a fusion performed in the second year in 1 patient because the patient reported continued pain. In the fusion group, adjacent segment disease was observed in 1 patient, with subsequent reoperation. Lumbar decompression and posterior dynamic transpedicular stabilization yield satisfactory results in the treatment of degenerative lumbar spondylolisthesis and can be considered a valid alternative to fusion. PMID:20506953

Kaner, Tuncay; Dalbayrak, Sedat; Oktenoglu, Tunc; Sasani, Mehdi; Aydin, Ahmet Levent; Ozer, Ali Fahir



Launch Collision Probability  

NASA Technical Reports Server (NTRS)

This report analyzes the probability of a launch vehicle colliding with one of the nearly 10,000 tracked objects orbiting the Earth, given that an object on a near-collision course with the launch vehicle has been identified. Knowledge of the probability of collision throughout the launch window can be used to avoid launching at times when the probability of collision is unacceptably high. The analysis in this report assumes that the positions of the orbiting objects and the launch vehicle can be predicted as a function of time and therefore that any tracked object which comes close to the launch vehicle can be identified. The analysis further assumes that the position uncertainty of the launch vehicle and the approaching space object can be described with position covariance matrices. With these and some additional simplifying assumptions, a closed-form solution is developed using two approaches. The solution shows that the probability of collision is a function of position uncertainties, the size of the two potentially colliding objects, and the nominal separation distance at the point of closest approach. ne impact of the simplifying assumptions on the accuracy of the final result is assessed and the application of the results to the Cassini mission, launched in October 1997, is described. Other factors that affect the probability of collision are also discussed. Finally, the report offers alternative approaches that can be used to evaluate the probability of collision.

Bollenbacher, Gary; Guptill, James D.



Posterior cortical atrophy: visuomotor deficits in reaching and grasping  

PubMed Central

Posterior Cortical Atrophy (PCA) is a rare clinical syndrome characterized by the predominance of higher-order visual disturbances such as optic ataxia, a characteristic of Balint's syndrome. Deficits result from progressive neurodegeneration of occipito-temporal and occipito-parietal cortices. The current study sought to explore the visuomotor functioning of four individuals with PCA by testing their ability to reach out and grasp real objects under various viewing conditions. Experiment 1 had participants reach out and grasp simple, rectangular blocks under visually- and memory-guided conditions. Experiment 2 explored participants' abilities to accurately reach for objects located in their visual periphery. This investigation revealed that PCA patients demonstrate many of the same deficits that have been previously reported in other individuals with optic ataxia, such as “magnetic misreaching”—a pathological reaching bias toward the point of visual fixation when grasping peripheral targets. Unlike many other individuals with optic ataxia, however, the patients in the current study also show symptoms indicative of damage to the more perceptual stream of visual processing, including abolished grip scaling during memory-guided grasping and deficits in face and object identification. These investigations are the first to perform a quantitative analysis of the visuomotor deficits exhibited by patients with PCA. Critically, this study helps characterize common symptoms of PCA, a vital first step for generating effective diagnostic criteria and therapeutic strategies for this understudied neurodegenerative disorder. PMID:23801956

Meek, Benjamin P.; Shelton, Paul; Marotta, Jonathan J.



A Study of Temporal Aspect of Posterior Parietal Cortex in Visual Search Using Transcranial Magnetic Stimulation  

NASA Astrophysics Data System (ADS)

It is known that the posterior parietal cortex (PPC) plays a dominant role in spatial processing during visual search. However, the temporal aspect of the PPC is unclear. In the present study, to investigate the temporal aspects of the PPC in feature search, we applied Transcranial Magnetic Stimulation (TMS) over the right PPC with the TMS stimulus onset asynchronies (SOAs) set at 100, 150, 200 and 250 ms after visual search stimulation. We found that when SOA was set at 150 ms, compared to the sham TMS condition, there was a significant elevation in response time when TMS pulses were applied. However, there was no significant difference between the TMS and sham TMS conditions for the other SOA settings. Therefore, we suggest that the spatial processing of feature search is probably processed in the posterior parietal cortex at about 150-170 ms after visual search stimuli presentation.

Ge, Sheng; Matsuoka, Akira; Ueno, Shoogo; Iramina, Keiji


The perception of probability.  


We present a computational model to explain the results from experiments in which subjects estimate the hidden probability parameter of a stepwise nonstationary Bernoulli process outcome by outcome. The model captures the following results qualitatively and quantitatively, with only 2 free parameters: (a) Subjects do not update their estimate after each outcome; they step from one estimate to another at irregular intervals. (b) The joint distribution of step widths and heights cannot be explained on the assumption that a threshold amount of change must be exceeded in order for them to indicate a change in their perception. (c) The mapping of observed probability to the median perceived probability is the identity function over the full range of probabilities. (d) Precision (how close estimates are to the best possible estimate) is good and constant over the full range. (e) Subjects quickly detect substantial changes in the hidden probability parameter. (f) The perceived probability sometimes changes dramatically from one observation to the next. (g) Subjects sometimes have second thoughts about a previous change perception, after observing further outcomes. (h) The frequency with which they perceive changes moves in the direction of the true frequency over sessions. (Explaining this finding requires 2 additional parametric assumptions.) The model treats the perception of the current probability as a by-product of the construction of a compact encoding of the experienced sequence in terms of its change points. It illustrates the why and the how of intermittent Bayesian belief updating and retrospective revision in simple perception. It suggests a reinterpretation of findings in the recent literature on the neurobiology of decision making. PMID:24490790

Gallistel, C R; Krishan, Monika; Liu, Ye; Miller, Reilly; Latham, Peter E



Signal probability calculations using partial functional manipulation  

E-print Network

University, India Chair of Advisory Committee: Dr. Don E. Ross Signal probability calculations are necessary to allow the random pattern testa- bility of circuits to be determined, to determine if a weighted or unweighted Linear Feedback Shift Register... the advantage that it uses a new method for signal proba- bility calculations which is typically both fast and accurate, and which has already effrciently produced results for all the ISCAS combinational circuits. ACKNOWLEDGMENTS The author wishes to express...

Kodavarti, Ravishankar



Postoperative acetabular retroversion causes posterior osteoarthritis of the hip  

PubMed Central

We retrospectively reviewed 68 hips in 62 patients with acetabular dysplasia who underwent curved periacetabular osteotomy. Among the 68 hips, 33 had acetabular retroversion (retroversion group) and 35 had anteversion (control group) preoperatively. All hips were evaluated according to the Harris hip score. Radiographic evaluations of acetabular retroversion and posterior wall deficiency were based on the cross-over sign and posterior wall sign, respectively. The clinical scores of the two groups at the final follow-up were similar. In the retroversion group, 12 hips had anteverted acetabulum postoperatively. The posterior wall sign disappeared in these hips, but remained in 21 hips with retroverted acetabulum postoperatively. Among the 21 hips with retroverted acetabulum, posterior osteoarthritis of the hip developed postoperatively in five hips. When performing corrective osteotomy for a dysplastic hip with acetabular retroversion, it is important to correct the acetabular retroversion to prevent posterior osteoarthritis of the hip due to posterior wall deficiency. PMID:18157533

Naito, Masatoshi; Shiramizu, Kei; Shinoda, Tsuyoshi



Venn Diagrams and Probability  

NSDL National Science Digital Library

This applet lets you highlight the set A, the set B, the set C, the universal set S, the empty set {}, the complement of A (Ac), the complement of B (Bc), the complement of C (Cc), the intersection of A and B (AB), the union of A and B (A or B), the intersection of the complement of A with B (AcB), the intersection of A with the complement of B (ABc), the intersection of A, B, and C (ABC), the union of A, B, and C (A or B or C), the intersection of Ac and B and C (AcBC), and the union of the complement of A and the intersection of B and C (Ac or BC). One can think of the relative area of a set to the area of S as a probability. You can drag the events A, B, and C around, which changes the probability of their intersection and of their union. This applet displays six conditional probabilities: P(A|B), P(Ac|B), P(B|A), P(A|BC), P(Ac|BC), and P(A|(B or C)). When the corresponding checkbox is ticked, the events whose probabilities are involved in computing the conditional probability are highlighted in contrasting colors.

Stark, Philip B.



Asymptomatic posterior mediastinal teratoma diagnosed incidentally.  


We present a young patient with occasional chest pain and an incidentally found posterior mediastinal mass on radiology which was confirmed as mature teratoma on histopathology. The gross specimen received in the department of pathology was globular measuring 9.0×7.0×5.5 cm and varying in consistency from soft cystic to firm. Cut surface showed numerous hair entangled in pultaceous material. Representative sections were taken and stained with H&E stain. Histopathology revealed haphazardly distributed mature derivatives of all the three germ layers comprising of epidermis, pilo sebaceous units, nerve bundles (ectodermal), cartilage, bone, salivary gland clusters, blood vessels, muscle bundles, fibrous tissue infiltrated by foreign body giant cells, lymphoid follicles (mesodermal) and pseudostratified columnar epithelium (mesodermal), thus establishing the diagnosis of mature teratoma. PMID:24654248

Jaiswal, Riddhi; Rani, Poonam; Devenraj, Vijayant



Posterior restorations--a clinical view.  


This paper examines the state-of-the-art in the direct restoration of posterior teeth. The existing paradigms for the management of caries are questioned and some existing methods of cavity preparation are reviewed. Dental restorations need to be durable but able to adapt to a changing environment brought about by wear of the adjacent tooth substance and by fatigue processes within the tooth itself. The wear of restorative materials needs to be matched to that of the tooth, otherwise differential loss of either the restorative material or the enamel may destabilize the occlusion. Esthetic instability due to natural darkening of the tooth with age, punctuated by clinical intervention with bleaching procedures, adds a further dimension to the concept of a permanent restoration. Clinical methods that minimize the disruptive effects of dental restorations upon the remaining tooth structure are a continuing challenge. PMID:11317380

Jedynakiewicz, N M; Martin, N



Electroclinical characteristics of posterior lateral temporal epilepsy.  


The current study aimed to investigate the electroclinical differences between mesial temporal lobe epilepsy (MTLE) and posterior lateral temporal lobe epilepsy (PLTLE). All patients had Engel class I outcomes after surgery for at least one year. In MTLE patients, the epileptogenic zone was inside the boundary of a standard temporal lobectomy, whereas in PLTLE, the epileptogenic zone was behind the boundary of a standard temporal lobectomy. Febrile convulsion, history of psychic aura, oroalimentary automatism, and diffuse interictal epileptiform discharges were more frequent in MTLE. Theta wave and increasing heart rate were more evident at the seizure onset in MTLE, whereas an ictal onset fast rhythm was more evident in PLTLE. Tonic head turning was more frequent in PLTLE. Distinguishing between MTLE and PLTLE was easier than distinguishing MTLE from lateral TLE (LTLE), which may be helpful in planning epilepsy surgery. Combinations of these manifestations and signs can provide vital clues to distinguish between MTLE and PLTLE. PMID:23200534

Wang, Fang; Liu, Xingzhou; Pan, Sipei; Wang, Mengyang; Chen, Shuhua



Posterior Thigh Muscle Injuries in Elite Track and Field Athletes  

Microsoft Academic Search

Introduction: Posterior thigh muscle injuries in athletes are common, and prediction of recovery time would be of value.Hypothesis: Knee active range of motion deficit 48 hours after a unilateral posterior thigh muscle injury correlates with time to full recovery.Study Design: Cohort study (prognosis); Level of evidence, 2.Methods: One hundred sixty-five track and field athletes with acute, first-time, unilateral posterior thigh

Nikolaos Malliaropoulos; Emmanuel Papacostas; Olga Kiritsi; Agapi Papalada; Nikolaos Gougoulias; Nicola Maffulli



Posterior cranial vault distraction with resorbable distraction devices.  


Posterior cranial vault distraction is recognized as a viable initial approach to patients with syndromic craniosynostosis. It offers advantages to initial anterior vault surgery and to traditional 1-stage advancements. Reports of posterior vault distraction have thus far focused on the use of standard titanium distractors. We present a case of posterior vault distraction with resorbable distraction devices, obviating the need for a second surgery and anesthetic for distractor removal. Distraction was performed successfully without complications or device-related issues. PMID:25006906

Maurice, Samuel M; Gachiani, John M



Subjective probability and delay.  


Human subjects indicated their preference between a hypothetical $1,000 reward available with various probabilities or delays and a certain reward of variable amount available immediately. The function relating the amount of the certain-immediate reward subjectively equivalent to the delayed $1,000 reward had the same general shape (hyperbolic) as the function found by Mazur (1987) to describe pigeons' delay discounting. The function relating the certain-immediate amount of money subjectively equivalent to the probabilistic $1,000 reward was also hyperbolic, provided that the stated probability was transformed to odds against winning. In a second experiment, when human subjects chose between a delayed $1,000 reward and a probabilistic $1,000 reward, delay was proportional to the same odds-against transformation of the probability to which it was subjectively equivalent. PMID:2037827

Rachlin, H; Raineri, A; Cross, D



Posterior Circulation Stroke: Animal Models and Mechanism of Disease  

PubMed Central

Posterior circulation stroke refers to the vascular occlusion or bleeding, arising from the vertebrobasilar vasculature of the brain. Clinical studies show that individuals who experience posterior circulation stroke will develop significant brain injury, neurologic dysfunction, or death. Yet the therapeutic needs of this patient subpopulation remain largely unknown. Thus understanding the causative factors and the pathogenesis of brain damage is important, if posterior circulation stroke is to be prevented or treated. Appropriate animal models are necessary to achieve this understanding. This paper critically integrates the neurovascular and pathophysiological features gleaned from posterior circulation stroke animal models into clinical correlations. PMID:22665986

Lekic, Tim; Ani, Chizobam



Data Analysis and Probability  

NSDL National Science Digital Library

With these activities you are going to brush up your data analysis skills and practice finding the probability of events! These games are fun, but you will be surprised how much you learn! Practice finding the mean, median, mode and range with this fun game! Determine the probability that an event will occur or an object will be selected! Review the information on reading bar graphs with this game and practice working with bar graphs when you are done. To see great examples of how data can be displayed, take some of the surveys on ...

Jackson, Ms.



Transforming Probabilities with Combinational Logic  

E-print Network

1 Transforming Probabilities with Combinational Logic Weikang Qian, Marc D. Riedel, Hongchao Zhou that have a specific probability of being one versus zero. If many different probability values are required probabilities into different target probabilities. We consider three different scenarios in terms of whether

Bruck, Jehoshua (Shuki)


An anatomic investigation of the serratus posterior superior and serratus posterior inferior muscles  

Microsoft Academic Search

In classical anatomy textbooks the serratus posterior superior muscle was said to elevate the superior four ribs, thus increasing\\u000a the AP diameter of the thorax and raising the sternum. However, electromyographic and other studies do not support its role\\u000a in respiration. In order to help resolve this controversy and provide some insight into their possible functionality, the\\u000a present study aimed

Marios Loukas; Robert G. Louis Jr; Christopher T. Wartmann; R. Shane Tubbs; Ankmalika A. Gupta; Nihal Apaydin; Robert Jordan



probability fully-observed  

E-print Network

does not depend on #18;, is the entropy. #15; Thus, in the M-step, maximizing with respect to #18 easier. Expectation-Maximization (EM) Algorithm #15; Iterative algorithm with two linked steps: E Gaussian #12;tting, linear regression) #15; With z unobserved, we need the log of a marginal probability

Roweis, Sam


The Meaning of Probability  

Microsoft Academic Search

IN his article on `The Meaning of Probability' in NATURE of September 14, Dr. Dingle has attempted to support his case by means of a striking example. Unfortunately his illustration is by no means happily chosen, and the issue may be further confused by his treatment of it in a way no one is likely to defend. When the truth

T. Smith



DISCUSS: Probability with Dice  

NSDL National Science Digital Library

This module, by Neville Hunt and Nicki Cologne-Brookes of Coventry University, teaches probability through dice simulations. Students will use Excel spreadsheets to simulate experiments of rolling 1 die, taking the sum of 2 dice, taking the difference of 2 dice, and rolling many dice. Instructions for creating a dice simulation in Excel are also given.

Cologne-Brookes, Nicki; Hunt, Neville




NSDL National Science Digital Library

We are going to work on probability today using dice, spinner\\'s, coins. Click on this website Dice Chances and click on the down arrow. Click on the last option, dice, and then click on each of the red boxes on the left side of the screen. See how many matches you find. Click on reset and clikc on the ...

Broadbent, Ms.



Probability and Cancer Clusters  

ERIC Educational Resources Information Center

Recently there have been several news items about possible cancer clusters in the Australian media. The term "cancer cluster" is used when an unusually large number of people in one geographic area, often a workplace, are diagnosed with cancer in a short space of time. In this paper the authors explore this important health issue using probability…

Hamilton-Keene, Rachael; Lenard, Christoper T.; Mills, Terry M.




E-print Network

107 or 108 of the 1976 United States Copyright Act, without either the prior written permission Probability and Stochastic Processes to Rutgers undergraduates in 1991, we never dreamed we would write, in itself, of minor interest. What the students want most is an intuitive grasp of the basic concepts

Kozick, Richard J.


Probability: A Project Approach  

NSDL National Science Digital Library

This article, created by Maita Levine and Raymond H. Rolwing of the University of Cincinnati, describes an assignment given in various introductory statistics courses and the experience of probability and statistics in the classroom. There are five different examples given in this lesson. Additionally, there are external references for those interesting in examining this topic at a more in-depth level.

Levine, Maita; Rolwing, Raymond H.



Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)  

PubMed Central

Introduction Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process. To date, Isodiametra pulchra is the most promising candidate as a model for the Acoelomorpha, as it reproduces steadily under laboratory conditions and is amenable to various techniques, including the silencing of gene expression by RNAi. In order to provide an essential framework for future studies, we report the succession of regeneration events via the use of cytochemical, histological and microscopy techniques, and specify the total number of cells in adult individuals. Results Isodiametra pulchra is not capable of regenerating a new head, but completely restores all posterior structures within 10 days. Following amputation, the wound closes via the contraction of local muscle fibres and an extension of the dorsal epidermis. Subsequently, stem cells and differentiating cells invade the wound area and form a loosely delimited blastema. After two days, the posterior end is re-patterned with the male (and occasionally the female) genital primordium being apparent. Successively, these primordia differentiate into complete copulatory organs. The size of the body and also of the male and female copulatory organs, as well as the distance between the copulatory organs, progressively increase and by nine days copulation is possible. Adult individuals with an average length of 670 ?m consist of approximately 8100 cells. Conclusion Isodiametra pulchra regenerates through a combination of morphallactic and epimorphic processes. Existing structures are “re-modelled” and provide a framework onto which newly differentiating cells are added. Growth proceeds through the intercalary addition of structures, mirroring the embryonic and post-embryonic development of various organ systems. The suitability of Isodiametra pulchra for laboratory techniques, the fact that its transcriptome and genome data will soon be available, as well as its small size and low number of cells, make it a prime candidate subject for research into the cellular mechanisms that underlie regeneration in acoelomorphs. PMID:24160844



An accurate iris location method for low quality iris images  

NASA Astrophysics Data System (ADS)

Iris location plays an important role in iris recognition system. Traditional iris location methods based on canny operator and integro-differential operator are affected by reflections, illumination inconsistency and eyelash. In this paper, we introduce an accurate iris location method for low quality iris images. First, a reflection removal method is used to interpolate the specular reflection. Then, we utilize Probable boundary (Pb) edge detection operator to detect papillary boundary with a lower interference point. Moreover, we optimize the Hough transform to obtain high accuracy result. Experimental results demonstrate that the location results of the proposed method are more accurate than other methods.

Wang, Ning; Li, Qiong; Abd El-Latif, Ahmed A.; Zhang, Tiejun; Peng, Jialiang



Big MACS: Accurate photometric calibration  

NASA Astrophysics Data System (ADS)

Big MACS is a Python program that estimates an accurate photometric calibration from only an input catalog of stellar magnitudes and filter transmission functions. The user does not have to measure color terms which can be difficult to characterize. Supplied with filter transmission functions, Big MACS synthesizes an expected stellar locus for your data and then simultaneously solves for all unknown zeropoints when fitting to the instrumental locus. The code uses a spectroscopic model for the SDSS stellar locus in color-color space and filter functions to compute expected locus. The stellar locus model is corrected for Milky Way reddening. If SDSS or 2MASS photometry is available for stars in field, Big MACS can yield a highly accurate absolute calibration.

Kelly, P. L.; von der Linden, A.; Applegate, D.; Allen, M.; Allen, S. W.; Burchat, P. R.; Burke, D. L.; Ebeling, H.; Capak, P.; Czoske, O.; Donovan, D.; Mantz, A.; Morris, R. G.



Combined posterior and transaxillary approach for neurogenic thoracic outlet syndrome  

Microsoft Academic Search

Background: Incomplete removal of the first rib in operations intended to decompress the thoracic outlet is often seen after the single transaxillary approach (often leaving a posterior stump) or supraclavicular techniques (leaving an anterior stump). The former may also cause neurogenic and vascular injuries because the exposure is often poor in attempting complete removal of the first rib posteriorly and

J. Ernesto Molina



Probability Out Of Determinism Michael Strevens  

E-print Network

;1. Deterministic Probability A deterministic probability is a physical probability sincerely ascribed by some in their "sincerity" concerning the probabilities' observer-independent existence). Deterministic probability is

Strevens, Michael


Automatic quantification of posterior capsule opacification  

NASA Astrophysics Data System (ADS)

After Cataract surgery where a plastic implant lens is implanted into the eye to replace the natural lens, many patients suffer from cell growth across a membrane situated at the back of the lens which degrades their vision. The cell growth is known as Posterior Capsule Opacification (or PCO). It is important to be able to quantify PCO so that the effect of different implant lens types and surgical techniques may be evaluated. Initial results obtained using a neural network to detect PCO from implant lenses are compared to an established but less automated method of detection, which segments the images using texture segmentation in conjunction with co- occurrence matrices. Tests show that the established method performs well in clinical validation and repeatability trials. The requirement to use a neural network to analyze the implant lens images evolved from the analysis of over 1000 images using the established co-occurrence matrix segmentation method. The work shows that a method based on neural networks is a promising tool to automate the procedure of calculating PCO.

Barman, Sarah A.; Uyyanonvara, Bunyarit; Boyce, James F.; Sanguinetti, Giorgia; Hollick, Emma J.; Meacock, William R.; Spalton, David J.; Paplinski, Andrew P.



Posterior likelihood methods for multivariate survival data.  


This article deals with the semiparametric analysis of multivariate survival data with random block (group) effects. Survival times within the same group are correlated as a consequence of a frailty random block effect. The standard approaches assume either a parametric or a completely unknown baseline hazard function. This paper considers an intermediate solution, that is, a nonparametric function that is reasonably smooth. This is accomplished by a Bayesian model in which the conditional proportional hazards model is used with a correlated prior process for the baseline hazard. The posterior likelihood based on data, as well as the prior process, is similar to the discretized penalized likelihood for the frailty model. The methodology is exemplified with the recurrent kidney infections data of McGilchrist and Aisbett (1991, Biometrics 47, 461-466), in which the times to infections within the same patients are expected to be correlated. The reanalysis of the data has shown that the estimates of the parameters of interest and the associated standard errors depend on the prior knowledge about the smoothness of the baseline hazard. PMID:9883545

Sinha, D



Posterior infectious crystalline keratopathy with Staphylococcus epidermidis.  


Two cases of infectious crystalline keratopathy located in the posterior stroma after penetrating keratoplasty are presented. Topical steroids and suture removal were risk factors in both cases. In the first case, a moderate anterior chamber reaction was present. Crystalline infiltrates persisted on topical and systemic steroid therapy. In the second case, deep corneal ulceration, hypopyon, and vitreitis were noted. A vitreous aspirate showed rare gram-positive cocci in pairs. The corneal ulceration and crystalline keratopathy persisted despite intravitreal and topical antibiotics. Therapeutic penetrating keratoplasty was performed in both cases. Staphylococcus epidermidis sensitive to vancomycin was isolated from corneal tissue. Light microscopy documented aggregates of gram-positive bacteria anterior to Descemet's membrane, with an overlying keratitis. Electron microscopy in the second case showed all bacteria within stromal keratocytes. No clinical recurrence was seen using topical vancomycin. As demonstrated in the cases presented, infectious crystalline keratopathy can occur exclusively in the deeper layers of the cornea. Isolation of S. epidermidis, associated inflammation, and intraocular spread of organisms are rare findings. PMID:2255518

Lubniewski, A J; Houchin, K W; Holland, E J; Weeks, D A; Wessels, I F; McNeill, J I; Cameron, J D



Vision through nuclear and posterior subcapsular cataract.  


We have developed a new set of tests for evaluation of visual function through media opacities, based on vernier acuity measurements (hyperacuity). In this paper, results of one of these tests, the 'gap test', are compared in patients with posterior subcapsular (PSC) cataract versus nuclear cataract (NC). Patients with PSC cataract often report multiple images or significant 'star burst' effects. We hypothesized the presence of 'multi-prismatic' and/or high frequency spurious resolution phenomena due to PSC cataract characteristic substructure. We were able to minimize these effects by using a pinhole held close to the eye, a large (adapting) background field of white light superimposed on the vernier test targets, a low-pass spatial filter applied to the targets. When the particular problems associated with PSC cataract are not present or are adequately addressed and when patients are matched for visual acuity, the hyperacuity 'gap test' shows less functional effect due to the opacity for PSC cataract than NC in all the cases we have tested. These findings, moreover, indicate that visual acuity provides an insufficient description of the effects of intraocular scattering on image formation. The results emphasize the importance and the necessity of developing models that better clarify the specific effects of different types of ocular media opacities. PMID:3721717

Baraldi, P; Enoch, J M; Raphael, S



Bayesian Probability Theory  

NASA Astrophysics Data System (ADS)

Preface; Part I. Introduction: 1. The meaning of probability; 2. Basic definitions; 3. Bayesian inference; 4. Combinatrics; 5. Random walks; 6. Limit theorems; 7. Continuous distributions; 8. The central limit theorem; 9. Poisson processes and waiting times; Part II. Assigning Probabilities: 10. Transformation invariance; 11. Maximum entropy; 12. Qualified maximum entropy; 13. Global smoothness; Part III. Parameter Estimation: 14. Bayesian parameter estimation; 15. Frequentist parameter estimation; 16. The Cramer–Rao inequality; Part IV. Testing Hypotheses: 17. The Bayesian way; 18. The frequentist way; 19. Sampling distributions; 20. Bayesian vs frequentist hypothesis tests; Part V. Real World Applications: 21. Regression; 22. Inconsistent data; 23. Unrecognized signal contributions; 24. Change point problems; 25. Function estimation; 26. Integral equations; 27. Model selection; 28. Bayesian experimental design; Part VI. Probabilistic Numerical Techniques: 29. Numerical integration; 30. Monte Carlo methods; 31. Nested sampling; Appendixes; References; Index.

von der Linden, Wolfgang; Dose, Volker; von Toussaint, Udo



Primer on Probability  

NSDL National Science Digital Library

How did Gregor Mendel derive the Law of Segregation and the Law of Independent Assortment? Most budding geneticists know he used peas, but how exactly did he do it? This fine document from Professor Robert Merritt of Smith College provides explanations of Mendel's groundbreaking work, along with information on the basic rules of probability. The 20-page document was developed for "Your Genes, Your Chromosomes," a course that was offered through the Smith College Summer Science and Engineering Program. The document explains how to test a hypothesis using The Chi-Square Test, and also covers topics such as sex determination and sex linkage, blood group, and gene interaction. Finally, the document contains a detailed explanation of the basic rules of probability and a selection of sample problems.

Merritt, Robert



Data Analysis: Probability  

NSDL National Science Digital Library

In this Bridges in Mathematics Supplement one spinner activity is used to build students' understanding of the probability terms: certain, impossible, equally likely, more likely, and less likely. Following this whole class/partner activity are two independent student worksheets that continue to build upon these concepts through spinner activities and practice. Three student worksheets and spinner templates are included with the lesson in PDF format.



Rocket Launch Probability  

NSDL National Science Digital Library

This applet is designed to teach an application of probability. This Java applet works by simulating a situation where a three stage rocket is about to be launched. In order for a successful launch to occur all three stages of the rocket must successfully pass their pre-takeoff tests. By default, each stage has a 50% chance of success, however, this can be altered by dragging the bar next to each stage.

Exner, Nicholas



Low probability of intercept  

Microsoft Academic Search

LOW Probability of Intercept (LPI) analysis shows the effect of scenario-dependent parameters and detectability-threshold factors in jamming and nonjamming environments. The most significant improvement in LPI performance may be obtained by operating at Extremely High Frequency (EHF) and by maximizing the effective spread-spectrum processing gain and the communicator’s antenna discrimination to the jamming signal, and by minimizing the number of




Probability in Quantum Mechanics  

Microsoft Academic Search

The concept of probability played an important role in the very beginning of ? quantum theory, when Max Planck (1858–1947)\\u000a postulated the discrete emission and absorption of radiation in a ? black body radiation. The quantum statistical mechanics\\u000a developed by Planck and his successors has extraordinary consequences treated elsewhere in this Compendium. Here, however,\\u000a the emphasis will be upon the

Abner Shimony


MAS5051 Probability and Probability Distributions Contents of Blocks  

E-print Network

transformations 38: The Poisson Process T 39/40 39: Introduction to Markov Chains 40: Basic Bayesian inference MASMAS5051 Probability and Probability Distributions Contents of Blocks Block "Lectures" Topics A 1/2 1: Sample spaces and events 2: Defining probabilities B 3/4 3: Conditional probability 4

Jordan, Jonathan


Robust Minimax Probability Machine Regression Robust Minimax Probability Machine Regression  

E-print Network

show how to compute a direct estimate of this probability for any given margin > 0. Following the idea with a known mean and covariance matrix. In other words, we maximize the minimum probability of our regressionRobust Minimax Probability Machine Regression Robust Minimax Probability Machine Regression Thomas

Mulligan, Jane


Massive hemoptysis: a rare presentation of posterior mediastinal, giant, benign vagal schwannoma.  


Schwannomas are rare neurogenic tumor originating from Schwann cells of the nerve sheath, most frequently encountered type of posterior mediastinal tumors. In most cases, schwannomas are benign, malignant and multiple schwannomas are rare. Histopathologically, the tumor is composed of fascicles of spindle cells, which are strongly positive for S-100 proteins. Surgical resection is a treatment of choice, and prognosis is excellent. Here, we report a case of posterior mediastinal schwannoma in a 20- years old male patient who complained of right-sided back pain and two episodes of massive hemoptysis of recent onset. Contrast enhanced computed tomography (CECT) and magnetic resonance imaging of the chest showed a well circumscribed, heterogeneous mass in the posterior mediastinum, compressing the right lower lobe with widening of intervertebral foramens. CT-guided trucut biopsy revealed spindle cell neoplasm. On immunohistochemistry, tumor cells expressed strong positivity for S-100 protein. Final diagnosis was schwannoma, probably originating from the right vagus nerve. Surgical resection of the encapsulated tumor resulted in the successful recovery, without any recurrence over next one year follow up. PMID:25365621

Das, Anirban; Choudhury, Sabyasachi; Basuthakur, Sumitra; Mukhopadhyay, Anghsuman; Mukherjee, Siddhartha



Approximation of Failure Probability Using Conditional Sampling  

NASA Technical Reports Server (NTRS)

In analyzing systems which depend on uncertain parameters, one technique is to partition the uncertain parameter domain into a failure set and its complement, and judge the quality of the system by estimating the probability of failure. If this is done by a sampling technique such as Monte Carlo and the probability of failure is small, accurate approximation can require so many sample points that the computational expense is prohibitive. Previous work of the authors has shown how to bound the failure event by sets of such simple geometry that their probabilities can be calculated analytically. In this paper, it is shown how to make use of these failure bounding sets and conditional sampling within them to substantially reduce the computational burden of approximating failure probability. It is also shown how the use of these sampling techniques improves the confidence intervals for the failure probability estimate for a given number of sample points and how they reduce the number of sample point analyses needed to achieve a given level of confidence.

Giesy. Daniel P.; Crespo, Luis G.; Kenney, Sean P.



Selective posterior rhizotomy for lower extremity spasticity: how much and which of the posterior rootlets should be cut?  

Microsoft Academic Search

BACKGROUNDIt is well known that selective posterior rhizotomy is effective for relieving spasticity associated with cerebral palsy. However, there is significant variation between surgeons in terms of how much and which of the posterior rootlets should be cut for the improvement of ambulatory function without causing adverse effects.METHODSThe study population was composed of 200 CP patients who underwent SPR more

Dong-Seok Kim; Joong-Uhn Choi; Kook-Hee Yang; Chang-Il Park; Eun-Sook Park



Efficient and accurate fragmentation methods.  


Conspectus Three novel fragmentation methods that are available in the electronic structure program GAMESS (general atomic and molecular electronic structure system) are discussed in this Account. The fragment molecular orbital (FMO) method can be combined with any electronic structure method to perform accurate calculations on large molecular species with no reliance on capping atoms or empirical parameters. The FMO method is highly scalable and can take advantage of massively parallel computer systems. For example, the method has been shown to scale nearly linearly on up to 131?000 processor cores for calculations on large water clusters. There have been many applications of the FMO method to large molecular clusters, to biomolecules (e.g., proteins), and to materials that are used as heterogeneous catalysts. The effective fragment potential (EFP) method is a model potential approach that is fully derived from first principles and has no empirically fitted parameters. Consequently, an EFP can be generated for any molecule by a simple preparatory GAMESS calculation. The EFP method provides accurate descriptions of all types of intermolecular interactions, including Coulombic interactions, polarization/induction, exchange repulsion, dispersion, and charge transfer. The EFP method has been applied successfully to the study of liquid water, ?-stacking in substituted benzenes and in DNA base pairs, solvent effects on positive and negative ions, electronic spectra and dynamics, non-adiabatic phenomena in electronic excited states, and nonlinear excited state properties. The effective fragment molecular orbital (EFMO) method is a merger of the FMO and EFP methods, in which interfragment interactions are described by the EFP potential, rather than the less accurate electrostatic potential. The use of EFP in this manner facilitates the use of a smaller value for the distance cut-off (Rcut). Rcut determines the distance at which EFP interactions replace fully quantum mechanical calculations on fragment-fragment (dimer) interactions. The EFMO method is both more accurate and more computationally efficient than the most commonly used FMO implementation (FMO2), in which all dimers are explicitly included in the calculation. While the FMO2 method itself does not incorporate three-body interactions, such interactions are included in the EFMO method via the EFP self-consistent induction term. Several applications (ranging from clusters to proteins) of the three methods are discussed to demonstrate their efficacy. The EFMO method will be especially exciting once the analytic gradients have been completed, because this will allow geometry optimizations, the prediction of vibrational spectra, reaction path following, and molecular dynamics simulations using the method. PMID:24810424

Pruitt, Spencer R; Bertoni, Colleen; Brorsen, Kurt R; Gordon, Mark S



Aspheric versus Spherical Posterior Chamber Intraocular Lenses  

PubMed Central

Purpose To compare spherical aberration and contrast sensitivity function following implantation of four different foldable posterior chamber intraocular lenses (IOLs), namely Sensar, Akreos AO, Tecnis, and AcrySof IQ. Methods In this randomized clinical trial, 68 eyes of 68 patients with senile cataracts underwent phacoemulsification and IOL implantation with Sensar (n=17), Akreos AO (n=17), Tecnis (n=17), or AcrySof IQ (n=17). Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), spherical aberration and contrast sensitivity function (CSF) were compared among the study groups, 3 months after surgery. Results There was no significant difference between the study groups in terms of age (P = 0.21). Mean postoperative BSCVA with Sensar, Akreos AO, Tecnis, and AcrySof IQ was 0.15±0.10, 0.12±0.9, 0.08±0.08, and 0.08±0.07 logMAR, respectively (P=0.08). Spherical aberration measured over a 4 mm pupil was significantly higher with Sensar and Akreos AO than the two other IOLs. The difference between Tecnis and AcrySof IQ was significantly in favor of the former IOL. Over a 6 mm pupil, spherical aberrations were comparable with Sensar and Akreos AO, furthermore spherical aberration was also comparable among eyes implanted with Akreos AO, AcrySof IQ, and Tecnis. Sensar yielded significantly inferior results as compared to Acrysof IQ and Tecnis. CSF with Sensar was inferior to the three aspheric IOLs at the majority of spatial frequencies. Tecnis yielded significantly better mesopic CSF at 1.5 and 3 cycles per degree spatial frequencies. Conclusion Tecnis and AcrySof IQ provided significantly better visual function as compared to Sensar and Akreos AO, especially with smaller pupil size. However, this difference diminished with increasing pupil size. PMID:22737364

Jafarinasab, Mohammad-Reza; Feizi, Sepehr; Baghi, Ahmad-Reza; Ziaie, Hossein; Yaseri, Mehdi



Phonological decoding involves left posterior fusiform gyrus.  


Aloud reading of novel words is achieved by phonological decoding, a process in which grapheme-to-phoneme conversion rules are applied to "sound out" a word's spoken representation. Numerous brain imaging studies have examined the neural bases of phonological decoding by contrasting pseudoword (pronounceable nonwords) to real word reading. However, only a few investigations have examined pseudoword reading under both aloud and silent conditions, task parameters that are likely to significantly alter the functional anatomy of phonological decoding. Subjects participated in an fMRI study of aloud pseudoword, aloud real word, silent pseudoword, and silent real word reading. Using this two-by-two design, we examined effects of word-type (real words vs. pseudowords) and response-modality (silent vs. aloud) and their interactions. We found 1) four regions to be invariantly active across the four reading conditions: the anterior aspect of the left precentral gyrus (Brodmann's Area (BA) 6), and three areas within the left ventral occipitotemporal cortex; 2) a main effect of word-type (pseudowords > words) in left inferior frontal gyrus and left intraparietal sulcus; 3) a main effect of response-modality (aloud > silent) that included bilateral motor, auditory, and extrastriate cortex; and 4) a single left hemisphere extrastriate region showing a word-type by response-modality interaction effect. This region, within the posterior fusiform cortex at BA 19, was uniquely modulated by varying phonological processing demands. This result suggests that when reading, word forms are subject to phonological analysis at the point they are first recognized as alphabetic stimuli and BA 19 is involved in processing the phonological properties of words. PMID:15934062

Dietz, Nicole A E; Jones, Karen M; Gareau, Lynn; Zeffiro, Thomas A; Eden, Guinevere F



Posterior fossa syndrome after cerebellar stroke.  


Posterior fossa syndrome (PFS) due to vascular etiology is rare in children and adults. To the best of our knowledge, PFS due to cerebellar stroke has only been reported in patients who also underwent surgical treatment of the underlying vascular cause. We report longitudinal clinical, neurocognitive and neuroradiological findings in a 71-year-old right-handed patient who developed PFS following a right cerebellar haemorrhage that was not surgically evacuated. During follow-up, functional neuroimaging was conducted by means of quantified Tc-99m-ECD SPECT studies. After a 10-day period of akinetic mutism, the clinical picture developed into cerebellar cognitive affective syndrome (CCAS) with reversion to a previously learnt accent, consistent with neurogenic foreign accent syndrome (FAS). No psychometric evidence for dementia was found. Quantified Tc-99m-ECD SPECT studies consistently disclosed perfusional deficits in the anatomoclinically suspected but structurally intact bilateral prefrontal brain regions. Since no surgical treatment of the cerebellar haematoma was performed, this case report is presumably the first description of pure, "non-surgical vascular PFS". In addition, reversion to a previously learnt accent which represents a subtype of FAS has never been reported after cerebellar damage. The combination of this unique constellation of poststroke neurobehavioural changes reflected on SPECT shows that the cerebellum is crucially implicated in the modulation of neurocognitive and affective processes. A decrease of excitatory impulses from the lesioned cerebellum to the structurally intact supratentorial network subserving cognitive, behavioural and affective processes constitutes the likely pathophysiological mechanism underlying PFS and CCAS in this patient. PMID:23575947

Mariën, Peter; Verslegers, Lieven; Moens, Maarten; Dua, Guido; Herregods, Piet; Verhoeven, Jo



Approximation to the Probability Density at the Output of a Photmultiplier Tube  

NASA Technical Reports Server (NTRS)

The probability density of the integrated output of a photomultiplier tube (PMT) is approximated by the Gaussian, Rayleigh, and Gamma probability densities. The accuracy of the approximations depends on the signal energy alpha: the Gamma distribution is accurate for all alpha, the Raleigh distribution is accurate for small alpha (approximate or less than 1 photon) and the Gaussian distribution is accurate for large alpha (approximate or greater than 10 photons).

Stokey, R. J.; Lee, P. J.



Document Ranking with Quantum Probabilities  

E-print Network

Document Ranking with Quantum Probabilities Guido Zuccon School of Computing Science College #12;To Andrea #12;Abstract In this thesis we investigate the use of quantum probability theory for ranking documents. Quantum probability theory is used to estimate the probability of relevance

Collings, Iain B.


Applied Probability & Stochastic Processes  

NSDL National Science Digital Library

Created by Professor Wlodzimierz Bryc of the University of Cincinnati, this course is aimed at students in applied fields and assumes a prerequisite of calculus. The goal is a working knowledge of the concepts and uses of modern probability theory. A significant part of such a "working knowledge" in modern applications of mathematics is computer-dependent. The course contains mathematical problems and computer exercises. Students will be expected to write and execute programs pertinent to the material of the course. No programming experience is necessary or assumed. But the willingness to accept a computer as a tool is a requirement.

Bryc, Wlodzimierz



Posterior decompression with instrumented fusion for thoracic myelopathy caused by ossification of the posterior longitudinal ligament.  


We evaluated the clinical results of posterior decompression with instrumented fusion (PDF) for thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL). A total of 24 patients underwent PDF, and their surgical outcomes were evaluated by the Japanese Orthopaedic Association (JOA) scores (0-11 points) and by recovery rates calculated at 3, 6, 9 and 12 months after surgery and at a mean final follow-up of 4 years and 5 months. The mean JOA score before surgery was 3.7 points. Although transient paralysis occurred immediately after surgery in one patient (3.8%), all patients showed neurological recovery at the final follow-up with a mean JOA score of 8.0 points and a mean recovery rate of 58.1%. The mean recovery rate at 3, 6, 9 and 12 months after surgery was 36.7, 48.8, 54.0 and 56.8%, respectively. The median time point that the JOA score reached its peak value was 9 months after surgery. No patient chose additional anterior decompression surgery via thoracotomy. The present findings demonstrate that despite persistent anterior impingement of the spinal cord by residual OPLL, PDF can result in considerable neurological recovery with a low risk of postoperative paralysis. Since neurological recovery progresses slowly after PDF, we suggest that additional anterior decompression surgery is not desirable during the early stage of recovery. PMID:20049486

Yamazaki, Masashi; Okawa, Akihiko; Fujiyoshi, Takayuki; Furuya, Takeo; Koda, Masao



Ossification of the posterior longitudinal ligament: a case report  

PubMed Central

Ossification of the posterior longitudinal ligament (OPLL) has recently been recognized as a clinical entity. It is a rare condition, having a higher incidence in the Japanese population. It is characterized by hyperplasia of cartilage cells with eventual endochondral ossification of the posterior longitudinal ligament. The radiographic signs are characteristic and consist of a linear band of ossified tissue along the posterior margin of the vertebral body. OPLL can be associated with mild to serious neurological complications due to spinal cord or nerve root compression, or it may be asymptomatic. This paper reviews the radiological, clinical and therapeutic aspects of this rare condition. ImagesFigures 1 and 2Figures 3 and 4

Aker, PD; O’Connor, SM; Mior, SA; Beauchemin, D



[Posterior reversible encephalopathy syndrome: 5 chemotherapy related cases].  


Posterior reversible encephalopathy syndrome, previously known as Reversible posterior leukoencephalopathy syndrome, is a clinical-radiological condition characterized by headache, altered mental functioning, seizures and visual alterations, with the magnetic resonance imaging showing cerebral edema, predominantly in the white matter with posterior distribution. Multiple clinical conditions can act as triggers. We present five oncology patients, four of them with acute lymphoblastic leukemia, receiving chemotherapy when they presented with this pathology. A prompt diagnosis, an appropriate therapy for hypertension, and a rapid control of the seizures are the keys to avoiding sequelae. PMID:23786801

San Martín García, I; Urabayen Alberdi, R; Díez Bayona, V; Sagaseta de Ilúrdoz Uranga, M; Esparza Estaun, J; Molina Garicano, J; Berisa Prado, S



Building the posterior lateral line system in zebrafish  

PubMed Central

The posterior lateral line in zebrafish has emerged as an excellent system to study how a sensory organ system develops. Here we review recent studies that illustrate how interactions between multiple signaling pathways coordinate cell fate, morphogenesis and collective migration of cells in the posterior lateral line primordium. These studies also illustrate how the posterior lateral line system is contributing much more broadly to our understanding of mechanisms operating during the growth, regeneration and self-organization of other organ systems during development and disease. PMID:21818862

Chitnis, Ajay B; Nogare, Damian Dalle; Matsuda, Miho



Bayesian Retrieval of Complete Posterior PDFs of Oceanic Rain Rate From Microwave Observations  

NASA Technical Reports Server (NTRS)

This paper presents a new Bayesian algorithm for retrieving surface rain rate from Tropical Rainfall Measurements Mission (TRMM) Microwave Imager (TMI) over the ocean, along with validations against estimates from the TRMM Precipitation Radar (PR). The Bayesian approach offers a rigorous basis for optimally combining multichannel observations with prior knowledge. While other rain rate algorithms have been published that are based at least partly on Bayesian reasoning, this is believed to be the first self-contained algorithm that fully exploits Bayes Theorem to yield not just a single rain rate, but rather a continuous posterior probability distribution of rain rate. To advance our understanding of theoretical benefits of the Bayesian approach, we have conducted sensitivity analyses based on two synthetic datasets for which the true conditional and prior distribution are known. Results demonstrate that even when the prior and conditional likelihoods are specified perfectly, biased retrievals may occur at high rain rates. This bias is not the result of a defect of the Bayesian formalism but rather represents the expected outcome when the physical constraint imposed by the radiometric observations is weak, due to saturation effects. It is also suggested that the choice of the estimators and the prior information are both crucial to the retrieval. In addition, the performance of our Bayesian algorithm is found to be comparable to that of other benchmark algorithms in real-world applications, while having the additional advantage of providing a complete continuous posterior probability distribution of surface rain rate.

Chiu, J. Christine; Petty, Grant W.



On the ability of global Ensemble Prediction Systems to predict tropical cyclone track probabilities  

E-print Network

probabilities Sharanya J. Majumdar and Peter M. Finocchio University of Miami, Miami, Florida Submitted The ability of ensemble prediction systems to predict the probability that a tropical cyclone will fall within to be more accurate than all models except its deterministic counterpart. Dynamic probability circles

Majumdar, Sharan


On numerically accurate finite element  

NASA Technical Reports Server (NTRS)

A general criterion for testing a mesh with topologically similar repeat units is given, and the analysis shows that only a few conventional element types and arrangements are, or can be made suitable for computations in the fully plastic range. Further, a new variational principle, which can easily and simply be incorporated into an existing finite element program, is presented. This allows accurate computations to be made even for element designs that would not normally be suitable. Numerical results are given for three plane strain problems, namely pure bending of a beam, a thick-walled tube under pressure, and a deep double edge cracked tensile specimen. The effects of various element designs and of the new variational procedure are illustrated. Elastic-plastic computation at finite strain are discussed.

Nagtegaal, J. C.; Parks, D. M.; Rice, J. R.



Laboratory transition probabilities for Gd II (Den Hartog+, 2006)  

Microsoft Academic Search

Radiative lifetimes, accurate to +\\/-5%, have been measured for 49 even-parity and 14 odd-parity levels of GdII using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of GdII transition probabilities and the first using a

E. A. den Hartog; J. E. Lawler; C. Sneden; J. J. Cowan



Transition probabilities for SmII (Lawler+, 2006)  

Microsoft Academic Search

Radiative lifetimes, accurate to +\\/-5%, have been measured for 212 odd-parity levels of SmII using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for more than 900 lines of SmII. This work is the largest scale laboratory study to date of SmII transition probabilities using modern methods. (2 data files).

J. E. Lawler; E. A. den Hartog; C. Sneden; J. J. Cowan



Quantum Computation Based Probability Density Function Estimation  

E-print Network

Signal processing techniques will lean on blind methods in the near future, where no redundant, resource allocating information will be transmitted through the channel. To achieve a proper decision, however, it is essential to know at least the probability density function (pdf), which to estimate is classically a time consumption and/or less accurate hard task, that may make decisions to fail. This paper describes the design of a quantum assisted pdf estimation method also by an example, which promises to achieve the exact pdf by proper setting of parameters in a very fast way.

Ferenc Balázs; Sándor Imre



CASE REPORT Pan-Suture Synostosis After Posterior Vault Distraction  

PubMed Central

Objective: Posterior vault remodeling by distraction osteogenesis is a relatively new technique used for initial correction of turribrachycephaly in children with bicoronal craniosynostosis. We present a new potential complication from this procedure; a case of pan-suture synostosis subsequent to posterior vault distraction. Methods: We report an infant girl who presented with bicoronal synostosis in the setting of Saethre-Chotzen syndrome. She underwent posterior vault distraction and was distracted a total of 34 millimeters, with successful osteogenesis at the site. Results: One year postoperatively, the patient was found to have incidental, asymptomatic pan-suture synostosis on computed tomography. Conclusions: To our knowledge, this is the first reported case of delayed craniosynostosis after posterior vault distraction in the literature. The possible pathogenesis and significance of this case are discussed with a review of the current literature. PMID:24106565

Chu, Katrina F.; Sullivan, Stephen R.; Taylor, Helena O.



CASE REPORT Osteoid Osteoma Invading the Posterior Labyrinth  

E-print Network

the cochlea but invaded the posterior labyrinth and the endolymphatic duct. There was a close relationship tumors.1,2 It is most frequently seen in teenagers and young adults and is very rare after 30 years


Behavioral/Systems/Cognitive Transcranial Magnetic Stimulation over Posterior Parietal  

E-print Network

Behavioral/Systems/Cognitive Transcranial Magnetic Stimulation over Posterior Parietal Cortex in transsaccadic memory in eight subjects by simultaneously applying single-pulse transcranial magnetic stimulation stimulation coincided more closely with saccade timing. Here, the capacity to compare presaccadic

Crawford, Doug


Post impingement in posterior stabilised total knee arthroplasty.  


Posterior stabilised implants are a well-proven treatment for patients requiring primary total knee arthroplasty. Concerns about the posterior stabilised (PS) design have been raised and recent studies suggest that the post-cam articulation can be an additional source of polyethylene wear debris. In this study, the authors report impingement of the tibial post against the patellar component in deep flexion in posterior stabilised total knee arthroplasty. Their data suggest that "post impingement" is associated with a raised joint line, patella infera, too anterior placement of the tibial component and a smaller femoral component size. "Post impingement" may lead to extensor mechanism problems and additional polyethylene wear and therefore may affect the longterm functional results of posterior stabilised total knee arthroplasty. PMID:15055317

Verborgt, Olivier; Victor, Jan



Vitrectorhexis versus forceps posterior capsulorhexis in pediatric cataract surgery  

PubMed Central

This study was done to compare the results of posterior continuous curvilinear capsulorhexis created using forceps with those created using vitrector in eyes suffering from congenital cataract. Vitrectorhexis term was first used by Wilson et al in 1999.[1] Fifty eyes with congenital and developmental cataract were included in this study. The posterior capsulorhexis was created using utrata forceps in 17 eyes or through a vitrector in 33 eyes. Forceps capsulorhexis was performed before IOL implantation, while vitrectorhexis was performed after IOL implantation in the bag. The results of both the surgery were compared using the following criteria: incidence of extension of rhexis, ability to achieve posterior rhexis of appropriate size, ability to implant the IOL in the bag, the surgical time, and learning curve. Vitrectorhexis after IOL implantation was an easy to learn alternative to manual posterior continuous curvilinear capsulorhexis in pediatric cataract surgery. It was more predictable and reproducible, with a short learning curve and lesser surgical time. PMID:23571249

Kochgaway, Lav; Biswas, Partha; Paul, Ajoy; Sinha, Sourav; Biswas, Rupak; Maity, Puspen; Banerjee, Sumita



Lens opacities after posterior chamber phakic intraocular lens implantation  

Microsoft Academic Search

PurposeTo describe a case series to determine the incidence of lens opacities after posterior chamber phakic intraocular lens (IOL) implantation (STAAR Surgical, Monrovia, CA) for very high ametropias.

C. ésar A Sánchez-Galeana; Ronald J Smith; Donald R Sanders; Francisco X Rodríguez; Sergio Litwak; Miguel Montes; Arturo S Chayet



The Logic of Parametric Probability  

E-print Network

The computational method of parametric probability analysis is introduced. It is demonstrated how to embed logical formulas from the propositional calculus into parametric probability networks, thereby enabling sound reasoning about the probabilities of logical propositions. An alternative direct probability encoding scheme is presented, which allows statements of implication and quantification to be modeled directly as constraints on conditional probabilities. Several example problems are solved, from Johnson-Laird's aces to Smullyan's zombies. Many apparently challenging problems in logic turn out to be simple problems in algebra and computer science; often just systems of polynomial equations or linear optimization problems. This work extends the mathematical logic and parametric probability methods invented by George Boole.

Norman, Joseph W



Myelolipoma of the posterior mediastinum: report of a case.  


Myelolipoma is an uncommon tumor composed of adipose tissue and normal hematopoietic elements, and is most often found in the adrenal glands. We report a patient with a posterior mediastinal myelolipoma. The 68-year-old male patient showed a right lower mediastinal shadow in a chest X-ray. A computed tomographic scan demonstrated a right posterior mediastinal mass. Magnetic resonance imaging provided additional useful information. The patient underwent a successful resection under video-assisted thoracoscopic surgery. PMID:23475269

Ema, Toshinari; Kawano, Ryoji



Posterior Retroperitoneoscopic Partial Adrenalectomy: Clinical Experience in 47 Procedures  

Microsoft Academic Search

Objectives: We evaluated posterior retroperitoneoscopic partial adrenalectomy with regard to operative complications, operation time, intraoperative blood loss.Patients and Methods: Between January 1997 and April 2002, we performed 47 posterior retroperitoneoscopic partial adrenalectomies. There were 18 males and 29 females with a mean age of 48 years (range 28–82 years). The average adrenal tumor size was 26mm (range 10–50mm). All procedures

Isoji Sasagawa; Yasuhiro Suzuki; Keiichi Itoh; Takuji Izumi; Michiharu Miura; Hitoshi Suzuki; Yoshihiko Tomita



Oculomotor nerve palsy secondary to aberrant posterior cerebral artery.  


The authors report a rare case of an oculomotor nerve palsy attributed to mass effect from an aberrant posterior cerebral artery. The patient presented with complete ptosis, mydriasis and ophthalmoplegia of the affected eye. MRI demonstrated distortion of the oculomotor nerve as it traversed inferior to the non-aneurysmal P1 segment of an aberrant posterior cerebral artery. The oculomotor nerve palsy resolved spontaneously. PMID:24980999

Tan, Terence; Tee, Jin Wee; Wang, Yi Yuen



Posterior fossa arachnoid cysts and cerebellar tonsillar descent: short review  

Microsoft Academic Search

The objective of this study was to analyze the association of cerebellar tonsillar descent and syringomyelia in patients with\\u000a posterior fossa arachnoid cysts. We reviewed the medical records of ten patients (mean, age 33; range, 24–49 years) diagnosed\\u000a with posterior fossa arachnoid cyst and tonsillar descent. Symptoms evolved over a mean of 12 months (range, 6 months to 3 years).\\u000a Syringomyelia was present in

Marcelo Galarza; Antonio López López-Guerrero; Juan F. Martínez-Lage



Regression of Symptomatic Syringomyelia after Resection of Posterior Fossa Tumour  

Microsoft Academic Search

Summary.  \\u000a ?Syringomyelia associated with posterior fossa tumours is a very infrequent combination of pathological entities. The few\\u000a cases which have been reported generally were asymptomatic in respect of the spinal cavitations. The authors report on a 36-year-old\\u000a woman with a large extradural posterior fossa epidermoid tumour with a concomitant holocord symptomatic syringomyelia. Some\\u000a of her symptoms were clearly attributed to

D. H. D'Osvaldo; J. M. Otero; J. B. Mosconi; J. D. Oviedo



Physical Constructivism and Quantum Probability  

NASA Astrophysics Data System (ADS)

I describe the main ideas of constructive physics and its role for the probability interpretation of quantum theory. It is shown how the explicit probability space for quantum systems gives the formal representation of entanglement and decoherence.

Ozhigov, Yu. I.



Logic, Geometry And Probability Theory  

E-print Network

We discuss the relationship between logic, geometry and probability theory under the light of a novel approach to quantum probabilities which generalizes the method developed by R. T. Cox to the quantum logical approach to physical theories.

Federico Holik



PROBabilities from EXemplars (PROBEX): a \\  

Microsoft Academic Search

PROBEX (PROBabilities from EXemplars), a model of probabilistic inference and probability judg- ment based on generic knowledge is presented. Its properties are that: (a) it provides an exemplar model satisfying bounded rationality; (b) it is a \\

Peter Juslin; Magnus Persson



How accurate is Limber's equation?  

E-print Network

The so-called Limber equation is widely used in the literature to relate the projected angular clustering of galaxies to the spatial clustering of galaxies in an approximate way. This paper gives estimates of where the regime of applicability of Limber's equation stops. Limber's equation is accurate for small galaxy separations but breaks down beyond a certain separation that depends mainly on the ratio sigma/R and to some degree on the power-law index, gamma, of spatial clustering xi; sigma is the one-sigma width of the galaxy distribution in comoving distance, and R the mean comoving distance. As rule-of-thumb, a 10% relative error is reached at 260 sigma/R arcmin for gamma~1.6, if the spatial clustering is a power-law. More realistic xi are discussed in the paper. Limber's equation becomes increasingly inaccurate for larger angular separations. Ignoring this effect and blindly applying Limber's equation can possibly bias results for the inferred spatial correlation. It is suggested to use in cases of doubt, or maybe even in general, the exact equation that can easily be integrated numerically in the form given in the paper.

P. Simon



How Accurate Is Peer Grading?  

PubMed Central

Previously we showed that weekly, written, timed, and peer-graded practice exams help increase student performance on written exams and decrease failure rates in an introductory biology course. Here we analyze the accuracy of peer grading, based on a comparison of student scores to those assigned by a professional grader. When students graded practice exams by themselves, they were significantly easier graders than a professional; overall, students awarded ?25% more points than the professional did. This difference represented ?1.33 points on a 10-point exercise, or 0.27 points on each of the five 2-point questions posed. When students graded practice exams as a group of four, the same student-expert difference occurred. The student-professional gap was wider for questions that demanded higher-order versus lower-order cognitive skills. Thus, students not only have a harder time answering questions on the upper levels of Bloom's taxonomy, they have a harder time grading them. Our results suggest that peer grading may be accurate enough for low-risk assessments in introductory biology. Peer grading can help relieve the burden on instructional staff posed by grading written answers—making it possible to add practice opportunities that increase student performance on actual exams. PMID:21123695

Parks, John W.



Using Particle Imaging Velocimetry to Measure Anterior-Posterior Velocity Gradients in the Excised Canine Larynx Model  

PubMed Central

Objectives To quantify the anterior-posterior velocity gradient, we studied the velocity flow fields above the vocal folds in both the midcoronal and midsagittal planes. It was also our purpose to use these fields to deduce the mechanisms that cause the anterior-posterior gradient and to determine whether the vortical structures are highly 3-dimensional. Methods Using the particle imaging velocimetry method for 5 excised canine larynges. we obtained phase-averaged velocity fields in the midcoronal and midsagittal planes for 30 phases of phonation. The velocity fields were determined synchronously with the vocal fold motion recorded by high-speed videography. Results The results show that immediately above the folds, there is no significant anterior-posterior velocity gradient. However, as the flow travels downstream, the laryngeal jet tends to narrow in width and skew toward the anterior commissure. Vortices are seen at the anterior and posterior edges of the flow. Conclusions The downstream narrowing in the midsagittal plane is consistent with and is probably due to a phenomenon known as axis switching. Axis switching also involves vortices in the sagittal and coronal planes bending in the axial plane. This results in highly 3-dimensional, complex vortical structures. However, there is remarkable cyclic repeatability of these vortices during a phonation cycle. PMID:18357838

Khosla, Sid; Murugappan, Shanmugam; Lakhamraju, Raghavaraju; Gutmark, Ephraim



Probability forecasts for storm surges  

E-print Network

of a storm surge Users SVSD, DNZ, DZL, Water boards, KNMI G G G G Deltares DMI Workshop 28 August 2007G G G G Probability forecasts for storm surges Hoek van Holland: Probability forecasts from Deltares DMI Workshop 28 August 2007, Probability forecasts for storm surges 1 #12;G G G G Storm surge

Stoffelen, Ad


Analytical Probability Distributions With Excel  

Microsoft Academic Search

This note introduces four common underlying processes and the analytical probability distribution used to forecast the outcomes of each. The note also illustrates how to use Excel functions to calculate probabilities from the four resulting probability distributions: binomial, normal, Poisson, and exponential.

Sherwood Frey; Phillip Pfeifer


The Probability of Causal Conditionals  

ERIC Educational Resources Information Center

Conditionals in natural language are central to reasoning and decision making. A theoretical proposal called the Ramsey test implies the conditional probability hypothesis: that the subjective probability of a natural language conditional, P(if p then q), is the conditional subjective probability, P(q [such that] p). We report three experiments on…

Over, David E.; Hadjichristidis, Constantinos; Evans, Jonathan St. B. T.; Handley, Simon J.; Sloman, Steven A.



[Postoperative opacification of posterior chamber intraocular lenses - a review].  


Postoperative opacification of intraocular lenses (IOLs) is a very unpleasant complication for the ophthalmic surgeon and the patient. We report on our experiences with opacification of different foldable IOL designs and rigid poly (methyl methacrylate) (PMMA) posterior chamber lenses.1. Snowflake degeneration of PMMA IOLs: This condition is an unanticipated and surprising late postoperative finding 8 to 15 years after implantation. In our opinion, this complication is probably not related to the PMMA biomaterial itself, but rather it appears to represent a manufacturing problem that has affected a selected, albeit large number of lenses manufactured in the 1980s-mid 1990s.2. Degeneration of UV absorber material and calcium deposits within the optic of hydrophilic IOLs: Two years postoperatively degenerations of UV absorber material and calcium deposits within the optic of single piece hydrophilic acrylic lenses SC60B-OUV manufactured by MDR (Medical developmental research Inc. Clearwater FL, USA) can occur. Although the precise mechanism is not fully known, it was assumed that these opacifications are due to premature aging of the UV blocking agent incorporated in the lens biomaterial and calcification.3. Calcification on the surface of the Bausch & Lomb Hydroviewtrade mark IOLs: Twelve to 15 months postoperatively granular surface calcifications in Hydroviewtrade mark IOLs occured. The mechanism is not fully understood. According to Bausch and Lomb studies, part of the components of the packaging contained silicone, which may have come off the packaging onto the lens optic, where it then appears to be a catalyst for calcium precipitation. The manufacturer has correlated a change in packaging with the appearance of the opacification. The manufacturer now believes that this problem has been solved. However, final verification will require a careful 1 - 2 years clinical study.4. Glistenings in the hydrophobic acrylic AcrySoftrade mark IOLs: The time frame of glistenings in the AcrySoftrade mark IOLs is highly variable. It has been suggested that the occurrence of glistenings may be related to variations in the temperature of the lens just prior to and or during insertion into the eye. Formation of vacuoles may occur within the submersed acrylic polymer when there is a transient increase and then decrease in temperature during the surgical procedure. "Glistenings" may then subsequently form by ingress of anterior chamber fluid. Contrast sensitivity can been decreased in some patients, but clinically significant decrease of visual acuity has been rare. PMID:11590465

Schmidbauer, J M; Werner, L; Apple, D J; Pandey, S K; Izak, A M; Trivedi, R H; Macky, T A; Auffarth, G U; Peng, Q; Arthur, S N; Escobar-Gomez, M; Ma, L; Vargas, L G



Seismic Hazard Assessment: Conditional Probability  

NSDL National Science Digital Library

In this exercise, students investigate the use of conditional probability (the likelihood that a given event will occur within a specified time period) in assessing earthquake hazards. Introductory materials explain that conditional probability is based on the past history of earthquakes in a region and on how and when earthquakes recur; and discuss the different types of models that can be developed to predict recurrences. Using a table of probability values, students will calculate probabilities for earthquakes along the San Andreas and Wasatch Fault zones, and calculate probabilities that they will exceed a given acceleration (ground shaking) value. Example problems and a bibliography are provided.

Pinter, Nicholas


Seismic Hazard Assessment: Conditional Probability  

NSDL National Science Digital Library

In this exercise, students investigate the use of conditional probability (the likelihood that a given event will occur within a specified time period) in assessing earthquake hazards. Introductory materials explain that conditional probability is based on the past history of earthquakes in a region and on how and when earthquakes recur; and discuss the different types of models that can be developed to predict recurrences. Using a table of probability values, students will calculate probabilities for earthquakes along the San Andreas and Wasatch Fault zones, and calculate probabilities that they will exceed a given acceleration (ground shaking) value. Example problems and a bibliography are provided.

Pinter, Nicholas



Minimally invasive endoscopic-assisted posterior thoracic sympathectomy.  


Palmar hyperhidrosis is a disorder of the autonomic nervous system characterized by excessive perspiration of the palms, but may involve other body parts as well. Traditional posterior approaches have been performed less often in favor of less invasive thoracoscopic sympathectomies, which have a high success rate with low associated morbidity. However, some patients are not candidates for a transthoracic surgery and may need an alternative treatment strategy. In situations in which a posterior approach may be necessary, the authors have developed a minimal access endoscopic-assisted dorsal sympathectomy procedure, applying minimally invasive spine muscle splitting techniques. The authors believe that the development of this technique may help to minimize surgical morbidity associated with the traditional posterior approach by reducing pain, tissue damage, and length of postoperative recovery. This paper is a report on the successful treatment of palmar hyperhidrosis using a minimally invasive posterior technique and describes the surgical approach and outcomes in 2 patients who have been treated in this manner. Two patients underwent minimally invasive endoscopic-assisted posterior thoracic sympathectomy for hyperhidrosis. Both patients experienced relief of their symptoms after surgery with follow-up durations of 32 and 9 months and length of stays of 0.9 and 2.8 days, respectively. One patient suffered a unilateral Horner syndrome and underwent an eyelid lift. The other patient was readmitted to the hospital 2 days after discharge with atelectasis. She was obese and suffered from chronic obstructive pulmonary disease at baseline, which were reasons she opted for a posterior approach. Neither patient suffered a pneumo- or hemothorax. Minimally invasive endoscopic-assisted posterior thoracic sympathectomy can be safely performed for relief of hyperhidrosis. The procedure has risks for the usual complications of sympathectomy. This technique may provide an alternative to thoracoscopic approaches, especially in those patients with pulmonary disease or obesity. PMID:18673054

Gardner, Paul A; Ochalski, Pawel G; Moossy, John J



Posterior transodontoid fixation: A new fixation (Kotil) technique.  


Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique), through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA) side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT) of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left) side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw) medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw) fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an alternative new technique among the previously defined C1-C2 fixation techniques in eligible cases. PMID:22013375

Kotil, Kad?r; Köksal, Neslihan Sütpideler; Kayac?, Selim



Posterior transodontoid fixation: A new fixation (Kotil) technique  

PubMed Central

Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique), through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA) side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT) of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left) side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw) medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw) fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an alternative new technique among the previously defined C1-C2 fixation techniques in eligible cases. PMID:22013375

Kotil, Kad?r; Köksal, Neslihan sütpideler; Kayac?, Selim



Posterior scissors-bite: masticatory jaw movement and muscle activity.  


Scissors-bite is a malocclusion characterised by buccal inclination or buccoversion of the maxillary posterior tooth and/or linguoclination or linguoversion of the mandibular posterior tooth. This type of malocclusion causes reduced contact of the occlusal surfaces and can cause excessive vertical overlapping of the posterior teeth. This case-control study is the first to evaluate both masticatory jaw movement and masseter and temporalis muscle activity in patients with unilateral posterior scissors-bite. Jaw movement variables and surface electromyography data were recorded in 30 adult patients with unilateral posterior scissors-bite malocclusion and 18 subjects with normal occlusion in a case-control study. The chewing pattern on the scissors-bite side significantly differed from that of the non-scissors-bite side in the patients and of the right side in the normal subjects. These differences included a narrower chewing pattern (closing angle, P < 0.01; cycle width, P < 0.01), a longer closing duration (P < 0.05), a slower closing velocity (P < 0.01) and lower activities of both the temporalis (P < 0.05) and the masseter (P < 0.05) muscles on the working side. In 96% of the patients with unilateral posterior scissors-bite, the preferred chewing side was the non-scissors-bite side (P = 0.005). These findings suggest that scissors-bite malocclusion is associated with the masticatory chewing pattern and muscle activity, involving the choice of the preferred chewing side in patients with unilateral posterior scissors-bite. PMID:24612226

Tomonari, H; Kubota, T; Yagi, T; Kuninori, T; Kitashima, F; Uehara, S; Miyawaki, S



Some New Twists to Problems Involving the Gaussian Probability Integral  

NASA Technical Reports Server (NTRS)

Using an alternate form of the Gaussian probability integral discovered a number of years ago, it is shown that the solution to a number of previously considered communication problems can be simplified and in some cases made more accurate(i.e., exact rather than bounded).

Simon, Marvin K.; Divsalar, Dariush



Treatment of noninfectious posterior uveitis with dexamethasone intravitreal implant  

PubMed Central

Purpose To report our experience with dexamethasone 0.7 mg sustained-release intravitreal implant (Ozurdex®; Allergan, Inc, Irvine, CA) in noninfectious posterior uveitis. Methods A retrospective chart review of patients with noninfectious uveitis treated with sustained-release dexamethasone 0.7 mg intravitreal implant was performed. Complete ophthalmic examination including signs of inflammatory activity, visual acuity, fundus photography, fluorescein angiography, optical coherence tomography, and tolerability of the implant were assessed. Results Six eyes of 4 consecutive patients treated with a total of 8 dexamethasone 0.7 mg sustained-release intravitreal implants for posterior noninfectious uveitis were included. Two patients presented with unilateral idiopathic posterior uveitis; 2 patients had bilateral posterior uveitis, one secondary to sarcoidosis and the other to Vogt-Koyanagi-Harada syndrome. All eyes showed clinical and angiographic evidence of decreased inflammation following implant placement. Mean follow-up time post-injection was 5.25 months. Four eyes received 1 and 2 eyes received 2 Ozurdex implants during the follow-up period. The duration of effect of the implant was 3 to 4 months. No serious ocular or systemic adverse events were noted during the follow-up period. Conclusions In patients with noninfectious posterior uveitis, sustained-release dexamethasone 0.7 mg intravitreal implant may be an effective treatment option for controlling intraocular inflammation. PMID:21188153

Myung, Jane S; Aaker, Grant D; Kiss, Szilard



Posteriorly migrated thoracic disc herniation: a case report  

PubMed Central

Introduction Posterior epidural migration of thoracic disc herniation is extremely rare but may occur in the same manner as in the lumbar spine. Case presentation A 53-year-old Japanese man experienced sudden onset of incomplete paraplegia after lifting a heavy object. Magnetic resonance imaging revealed a posterior epidural mass compressing the spinal cord at the T9-T10 level. The patient underwent emergency surgery consisting of laminectomy at T9-T10 with right medial facetectomy, removal of the mass lesion, and posterior instrumented fusion. Histological examination of the mass lesion yielded findings consistent with sequestered disc material. His symptoms resolved, and he was able to resume walking without a cane 4 weeks after surgery. Conclusions Pre-operative diagnosis of posterior epidural migration of herniated thoracic disc based on magnetic resonance imaging alone may be overlooked, given the rarity of this pathology. However, this entity should be considered among the differential diagnoses for an enhancing posterior thoracic extradural mass. PMID:23402642



Instrumented Posterior Lumbar Interbody Fusion in Adult Spondylolisthesis  

PubMed Central

It is unclear whether using artificial cages increases fusion rates compared with use of bone chips alone in posterior lumbar interbody fusion for patients with lumbar spondylolisthesis. We hypothesized artificial cages for posterior lumbar interbody fusion would provide better clinical and radiographic outcomes than bone chips alone. We assumed solid fusion would provide good clinical outcomes. We clinically and radiographically followed 34 patients with spondylolisthesis having posterior lumbar interbody fusion with mixed autogenous and allogeneic bone chips alone and 42 patients having posterior lumbar interbody fusion with implantation of artificial cages packed with morselized bone graft. Patients with the artificial cage had better functional improvement in the Oswestry disability index than those with bone chips alone, whereas pain score, patient satisfaction, and fusion rate were similar in the two groups. Postoperative disc height ratio, slip ratio, and segmental lordosis all decreased at final followup in the patients with bone chips alone but remained unchanged in the artificial cage group. The functional outcome correlated with radiographic fusion status. We conclude artificial cages provide better functional outcomes and radiographic improvement than bone chips alone in posterior lumbar interbody fusion for lumbar spondylolisthesis, although both techniques achieved comparable fusion rates. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18846411

Yu, Ching-Hsiao; Wang, Chen-Ti



Conditionalization for Interval Probabilities Alex Dekhtyar  

E-print Network

Conditionalization for Interval Probabilities Alex Dekhtyar Department probability distribution given a joint probability distribution of two or more random variables probability distribution is straightforward when the exact point probabilities are involved, it is often

Dekhtyar, Alexander


Conservative treatment of a tibialis posterior strain in a novice triathlete: a case report  

Microsoft Academic Search

Objective: To detail the progress of a novice triathlete with an unusual mechanism of a tibialis posterior strain who underwent successful conservative treatment and rehabilitation. Tibialis posterior tendon dysfunction will be discussed as it relates to the case. Clinical Features: The clinical features of tibialis posterior dysfunction are swelling and edema posterior to the medial malleolus with pain and an

Scott Howitt; Sarah Jung; Nicole Hammonds


Rupture of Posterior Cruciate Ligament: Diagnosis and Treatment Principles  

PubMed Central

Posterior cruciate ligament (PCL) injuries associated with multiple ligament injuries can be easily diagnosed, but isolated PCL tears are less symptomatic, very difficult to diagnose, and frequently misdiagnosed. If a detailed investigation of the history of illness suggests a PCL injury, careful physical examinations including the posterior drawer test, dial test, varus and valgus test should be done especially if the patient complains of severe posterior knee pain in >90° of flexion. Vascular assessment and treatment should be done to avoid critical complications. An individualized treatment plan should be established after consideration of the type of tear, time after injury, associated collateral ligament injuries, bony alignment, and status of remnant. The rehabilitation should be carried out slower than that after anterior cruciate ligament reconstruction. PMID:22570824

Nam, Shin Woo



An assessment of grafts in the posterior cricoid lamina.  


Subglottic stenosis is a recognized complication of prolonged intubation. To date, there is no uniformly successful operative procedure for severe subglottic stenosis, fulfilling the criteria of decannulation and a serviceable voice. The surgical ideals for such a procedure should include the use of autogenous grafting material, avoidance of internal stenting, and limited manipulation of the mucosa. This study was intended to assess the fate of isolated hyoid and thyroid alar grafts interposed in the posterior cricoid lamina. Additionally, anterior/posterior splits with and without anterior grafting were evaluated. Seventeen dogs were used in the determinate animal model. Vocal cord mobility was evaluated by direct laryngoscopy prior to sacrifice. Graphic gross anatomical specimens depict the effects of anterior/posterior splitting on the cricoid cartilage. Clinical correlations are suggested. PMID:7132512

Strome, M; Norris, C M; Joseph, M P; Brodsky, G; Eavey, R D



Ganglion cyst of the posterior longitudinal ligament causing lumbar radiculopathy.  


Degenerated conditions such as herniated disc or spinal stenosis are common etiologies of lumbar radiculopathy. Less common etiologies include spinal extradural cyst such as synovial cysts and ganglion cysts. Ganglion cyst of the posterior longitudinal ligament (PLL) of the spine is a rare entity that can result in classical sciatica. Posterior longitudinal ligament cyst has no continuity with the facet joint and has no epithelial lining. Two young male patients presented with unilateral sciatica and were found to have intraspinal cystic lesions causing lumbar radiculopathy. Magnetic resonance imaging demonstrated rounded, cystic lesions (i.e., hypointense on T1- but hyperintense on T2-weighted images) adjacent to minimally dehydrated, nonherniated disc spaces in both cases. These patients underwent posterior decompression and cysts were excised, and their sciatic symptoms were completely resolved. Histological examination showed typical features of ganglion cysts in these cases. PMID:20461173

Cho, Sung-Min; Rhee, Woo-Tack; Lee, Sang-Youl; Lee, Sang-Bok



Pathoanatomy of posterior ankle impingement in ballet dancers.  


Dance is a high performance athletic activity that leads to great numbers of injuries, particularly in the ankle region. One reason for this is the extreme range of ankle motion required of dancers, especially females in classical ballet where the en pointe and demi-pointe positions are common. These positions of maximal plantar flexion produce excessive force on the posterior ankle and may result in impingement, pain, and disability. Os trigonum and protruding lateral talar process are two common and well-documented morphological variations associated with posterior ankle impingement in ballet dancers. Other less well-known conditions, of both bony and soft tissue origins, can also elicit symptoms. This article reviews the anatomical causes of posterior ankle impingement that commonly affect ballet dancers with a view to equipping healthcare professionals for improved effectiveness in diagnosing and treating this pathology in a unique type of athlete. PMID:20821398

Russell, Jeffrey A; Kruse, David W; Koutedakis, Yiannis; McEwan, Islay M; Wyon, Matthew A



Sensitivity of posterior parameter correlations and response parameter correlations to prior response uncertainty  

SciTech Connect

The two parameters one response model of the generalized linear least squares parameter adjustment methodology was used in order to analyze the procedure of improving cross sections agreement with integral experimental results. Two extreme adjustment cases were considered. One case is using extremely accurate measured integral responses, such as k{sub eff} of Godiva or Jezebel for instance. The other one is modifying only one parameter, for instance the modification of {nu}-bar in ENDF/B-VII, in order to improve agreement of calculated responses with corresponding integral measurements results. In both cases new posterior parameters correlations are generated. The conclusion is that it is not advised to use integral measurements information in the evaluation process of a general purpose nuclear data file. (authors)

Wagschal, J. J. [Racah Inst. of Physics, Hebrew Univ. of Jerusalem, Edmond J. Safra Campus, Jerusalem, 91904 (Israel)



Barentsz is essential for the posterior localization of oskar mRNA and colocalizes with it to the posterior pole  

PubMed Central

The localization of Oskar at the posterior pole of the Drosophila oocyte induces the assembly of the pole plasm and therefore defines where the abdomen and germ cells form in the embryo. This localization is achieved by the targeting of oskar mRNA to the posterior and the localized activation of its translation. oskar mRNA seems likely to be actively transported along microtubules, since its localization requires both an intact microtubule cytoskeleton and the plus end–directed motor kinesin I, but nothing is known about how the RNA is coupled to the motor. Here, we describe barentsz, a novel gene required for the localization of oskar mRNA. In contrast to all other mutations that disrupt this process, barentsz-null mutants completely block the posterior localization of oskar mRNA without affecting bicoid and gurken mRNA localization, the organization of the microtubules, or subsequent steps in pole plasm assembly. Surprisingly, most mutant embryos still form an abdomen, indicating that oskar mRNA localization is partially redundant with the translational control. Barentsz protein colocalizes to the posterior with oskar mRNA, and this localization is oskar mRNA dependent. Thus, Barentsz is essential for the posterior localization of oskar mRNA and behaves as a specific component of the oskar RNA transport complex. PMID:11481346

van Eeden, Fredericus J.M.; Palacios, Isabel M.; Petronczki, Mark; Weston, Matthew J.D.; St Johnston, Daniel



Change-point diagnostics in competing risks models: Two posterior predictive p-value approaches  

PubMed Central

This paper presents a Bayesian diagnostic procedure for examining change-point assumption in the competing risks model framework. It considers the family of distributions arising from the cause-specific model as reported by Chiang (Introduction to stochastic processes in biostatistics. Wiley, New York, 1968) upon which change-points are added to accommodate possible distributional heterogeneity. Model departure, due to misspecification of change-points associated with either the overall survival distribution or cause-specific probabilities, is quantified in terms of a sequence of cumulative-sum statistics between each pair of adjacent change-points assumed. When assessing the asymptotic behavior of each sequence of cumulative-sum statistics using its posterior predictive p-values, see Rubin (Ann Stat 12:1151–1172, 1984) and partial posterior predictive p-values as reported by Bayarri and Berger (J Am Stat Assoc 95:1127–1142, 2000), we show that both types of p-values attain their greatest departure from 0.5 at the change-point that is missed in the assumed model, from which a diagnostic procedure is formalized. Statistical power of these two types of p-values is discussed.

Ghosh, Malay



Revisiting the Schrodinger probability current  

E-print Network

We revisit the definition of the probability current for the Schrodinger equation. First, we prove that the Dirac probability currents of stationary wave functions of the hydrogen atom and of the isotrop harmonic oscillator are not nil and correspond to a circular rotation of the probability. Then, we recall how it is necessary to add to classical Pauli and Schrodinger currents, an additional spin-dependant current, the Gordan current. Consequently, we get a circular probability current in the Schrodinger approximation for the hydrogen atom and the isotrop harmonic oscillator.

Michel Gondran; Alexandre Gondran



[Research advances in aggressive posterior retinopathy of prematurity].  


Aggressive posterior retinopathy of prematurity (AP-ROP) is a special kind of ROP, which is characterized by ill-defined, dilated and tortuous vessels in the posterior portion of the eye and rapidly progresses to severe ROP with retinal detachment. As more and more AP-ROP cases, who usually have poor prognosis, have been found, this disease has been increasingly noted. Which premature infants are at risks? How to make earlier diagnosis? Is there any better treatment protocols? There is much research about AP-ROP and this article summarizes the risks, screening, diagnosis and treatment of this disease. PMID:25008892

Zhang, Wei; Chen, Chao



Posterior palatal seal adaptation: influence of a high expansion stone.  


In this follow-up investigation, the ability of a new, high expansion stone to reduce acrylic resin denture base processing distortions was studied and compared with a previously reported investigation of bases processed on buff stone. Denture bases were processed by the continuous-injection and trial-pack techniques on flat vault palate casts and then trimmed and polished. Measurements were made at the posterior palatal border opening at 1 day and 1 week immersion in water (23 degrees C). Results showed that denture bases processed on high expansion stone had better posterior palatal seal adaptation compared with those processed on buff stone, independent of processing techniques. PMID:8736447

Sykora, O; Sutow, E J



Lesions in the ocular posterior segment of raptors.  


Thirty-eight free-living raptors, including various hawks, owls, and an eagle, had lesions of the ocular posterior segment believed to be the result of trauma. Although lesions of the anterior ocular segment and of the rest of the body often were seen, the lesions of the posterior segment of the eye were disproportionately more severe and usually were not suspected by rehabilitation personnel. The tightly encased raptor eye, with its anteriorly placed scleral ossicles, may have rendered the eye more susceptible to contrecoup damage. In the birds that were treated, ocular lesions were resolved and some vision was restored. PMID:4077621

Buyukmihci, N C



Agenesis of the mitral posterior leaflet in elderly.  


Congenital mitral valve regurgitation is a rare disease that is found in infancy and childhood, and sometimes in elderly people. In the case presented, mitral regurgitation that was tolerated well until the sixth decade of life is reported. A 62-year-old male suffering from dyspnea was referred to our hospital. Transthoracic echocardiographic examination demonstrated severe mitral regurgitation with suspicion of agenesis of the posterior leaflet with a long, mobile anterior leaflet. A transesophageal echocardiogram and surgical evaluation verified agenesis of the posterior mitral valve. The patient was successfully treated using mitral valve replacement, and no complications occurred. PMID:24384183

Ozkan, Hakan; Tiryakioglu, Osman; Cetinkaya, Ahmet Seckin; Uyanik, Elif Ceylan; Bozat, Tahsin



Bilambdoid and posterior sagittal synostosis: the Mercedes Benz syndrome.  


A consistent pattern of craniosynostosis in the sagittal and bilateral lambdoid sutures is described in three patients. The external cranial ridging associated with fusion of these sutures produces a characteristic triradiate, or "Mercedes Benz," appearance to the posterior skull. Locally marked growth restriction is evident in the posterior fossa with compensatory secondary expansion of the anterior fossa manifesting a degree of frontal bossing which mimics bicoronal synostosis. Although this appearance could lead to inadvertent surgery in the frontal region, attention to the occipital region with wide early suture excision and vault shaping is indicated. PMID:9780908

Moore, M H; Abbott, A H; Netherway, D J; Menard, R; Hanieh, A



Pedicle Screw-Based Posterior Dynamic Stabilization: Literature Review  

PubMed Central

Posterior dynamic stabilization (PDS) indicates motion preservation devices that are aimed for surgical treatment of activity related mechanical low back pain. A large number of such devices have been introduced during the last 2 decades, without biomechanical design rationale, or clinical evidence of efficacy to address back pain. Implant failure is the commonest complication, which has resulted in withdrawal of some of the PDS devices from the market. In this paper the authors presented the current understanding of clinical instability of lumbar motions segment, proposed a classification, and described the clinical experience of the pedicle screw-based posterior dynamic stabilization devices. PMID:23227349

Sengupta, Dilip K.; Herkowitz, Harry N.



Ultrasound in the diagnosis of posterior tibial tendon pathology.  


We retrospectively evaluated the effectiveness of ultrasonography as a diagnostic tool for investigating pathology in the posterior tibial tendon by comparing the preoperative ultrasonograms for 17 patients with their recorded surgical findings. In all cases, the surgical findings confirmed the ultrasonographic diagnoses: 3 inflammations, 4 partial tears, and 10 ruptures. Interestingly, two ruptures had been undiagnosed by magnetic resonance imaging. Ultrasonography, which seems to be a reliable means of visualizing the extent of pathology of the symptomatic posterior tibial tendon, may be a valuable tool in surgical planning. PMID:8886783

Miller, S D; Van Holsbeeck, M; Boruta, P M; Wu, K K; Katcherian, D A



Anterior-Posterior Thigh Diameter Measured by Two-Dimensional Sonography  

PubMed Central

Objective: Little published research exists in the area of fetal thigh biometry, specifically in the use of the anteriorposterior fetal thigh diameter (APTD). A continuing review of existing practices needs to be coupled with evaluation of alternate or additional methodology. This study evaluated the usefulness and direct correlation of a simple, new method of predicting fetal age by measurement of the anterior-posterior thigh diameter (APTD) in a normal 18-to 28 week pregnancies using two-dimensional sonography. Methods: This was a quantitative prospective study of 55 patients in the High Level General Hospital, Alberta, Canada. Anterior-posterior thigh diameters (APTD) were sonographically measured and the normal range for each week of pregnancy was determined five times for reliability. Results: Significant correlation was found between (APTD) and fetal age from simple line regression analysis, with >99.9% confidence intervals at each week from 18 to 28 weeks gestation. There was a correlation of 1 mm APTD per 1 week of fetal age. The standard error of estimation was very low at (0.08664) in edition (r>0.9993) and (p < than 0.0001). The residual scatter plots confirmed the APTD validity. Conclusion: APTD is a reliable and valid method for assessing fetal age in a normal pregnancy and may be particularly useful when other parameters are unable accurately to predict fetal age. An accurate linear measurement of multiple fetal parameters allows a more complete profile of fetal growth and estimated date of delivery (EDD). APTD may also be useful in identifying fetal growth problems. All of the values of fetal age lie directly on the “best-fit” regression line. Since the coefficient of determination (Rsq) is very high, this model is very effective. PMID:21748135

Al-Kubaisi, Saad R I



The relationship between species detection probability and local extinction probability  

USGS Publications Warehouse

In community-level ecological studies, generally not all species present in sampled areas are detected. Many authors have proposed the use of estimation methods that allow detection probabilities that are <1 and that are heterogeneous among species. These methods can also be used to estimate community-dynamic parameters such as species local extinction probability and turnover rates (Nichols et al. Ecol Appl 8:1213-1225; Conserv Biol 12:1390-1398). Here, we present an ad hoc approach to estimating community-level vital rates in the presence of joint heterogeneity of detection probabilities and vital rates. The method consists of partitioning the number of species into two groups using the detection frequencies and then estimating vital rates (e.g., local extinction probabilities) for each group. Estimators from each group are combined in a weighted estimator of vital rates that accounts for the effect of heterogeneity. Using data from the North American Breeding Bird Survey, we computed such estimates and tested the hypothesis that detection probabilities and local extinction probabilities were negatively related. Our analyses support the hypothesis that species detection probability covaries negatively with local probability of extinction and turnover rates. A simulation study was conducted to assess the performance of vital parameter estimators as well as other estimators relevant to questions about heterogeneity, such as coefficient of variation of detection probabilities and proportion of species in each group. Both the weighted estimator suggested in this paper and the original unweighted estimator for local extinction probability performed fairly well and provided no basis for preferring one to the other.

Alpizar-Jara, R.; Nichols, J.D.; Hines, J.E.; Sauer, J.R.; Pollock, K.H.; Rosenberry, C.S.



Pippi - painless parsing, post-processing and plotting of posterior and likelihood samples  

E-print Network

Interpreting samples from likelihood or posterior probability density functions is rarely as straightforward as it seems it should be. Producing publication-quality graphics of these distributions is often similarly painful. In this short note I describe pippi, a simple, publicly-available package for parsing and post-processing such samples, as well as generating high-quality PDF graphics of the results. Pippi is easily and extensively configurable and customisable, both in its options for parsing and post-processing samples, and in the visual aspects of the figures it produces. I illustrate some of these using an existing supersymmetric global fit, performed in the context of a gamma-ray search for dark matter. Pippi can be downloaded and followed at .

Pat Scott



Pippi — Painless parsing, post-processing and plotting of posterior and likelihood samples  

NASA Astrophysics Data System (ADS)

Interpreting samples from likelihood or posterior probability density functions is rarely as straightforward as it seems it should be. Producing publication-quality graphics of these distributions is often similarly painful. In this short note I describe pippi, a simple, publicly available package for parsing and post-processing such samples, as well as generating high-quality PDF graphics of the results. Pippi is easily and extensively configurable and customisable, both in its options for parsing and post-processing samples, and in the visual aspects of the figures it produces. I illustrate some of these using an existing supersymmetric global fit, performed in the context of a gamma-ray search for dark matter. Pippi can be downloaded and followed at

Scott, Pat



Pippi - painless parsing, post-processing and plotting of posterior and likelihood samples  

E-print Network

Interpreting samples from likelihood or posterior probability density functions is rarely as straightforward as it seems it should be. Producing publication-quality graphics of these distributions is often similarly painful. In this short note I describe pippi, a simple, publicly-available package for parsing and post-processing such samples, as well as generating high-quality PDF graphics of the results. Pippi is easily and extensively configurable and customisable, both in its options for parsing and post-processing samples, and in the visual aspects of the figures it produces. I illustrate some of these using an existing supersymmetric global fit, performed in the context of a gamma-ray search for dark matter. Pippi can be downloaded and followed at

Scott, Pat



Simultaneous avulsion fracture of the posterior medial and posterior lateral meniscus root: a case report and review of the literature.  


Injuries of the meniscus roots are increasingly recognized as a serious knee joint pathology. An avulsion fracture of the meniscus root is a rare variant of this injury pattern. In this article, a case of a traumatic simultaneous avulsion fracture of both the posterior medial and posterior lateral meniscus root associated with a tear of the anterior cruciate ligament is presented. Both avulsion fractures were treated by indirect arthroscopic transtibial pullout fixation of the bony fragment. Based on the findings of our literature review, root avulsion fractures seem to be more common in young male patients after an acute trauma to the knee joint. PMID:24337588

Feucht, Matthias J; Salzmann, Gian M; Pestka, Jan M; Südkamp, Norbert P; Niemeyer, Philipp



Numerical Computations of Separability Probabilities  

E-print Network

We compute the probability that a bipartite quantum state is separable by Monte Carlo sampling. This is carried out for rebits, qubits and quaterbits. We sampled $5\\times 10^{11}$ points for each of these three cases. The results strongly support conjectures for certain rational values of these probabilities that have been found by other methods.

Jianjia Fei; Robert Joynt




E-print Network

Probability Distributions, Dis- crete Probability Distributions, Genetic Algorithm, Inverse Transformation estimation methods like maximum-likelihood. We use the genetic algorithm for that. The design of the composed for the inverse transformation method for generating random variates. The common way to select a standard

Strelen, Christoph



E-print Network

THE DISCOVERY OF ALGORITHMIC PROBABILITY Ray J. Solomono# # Royal Holloway, University of London will describe a voyage of discovery --- the discovery of Algorithmic Probability. But before I describe, the motivation is discovery itself --- the joy of ``going where no one has gone before'' --- the excitement

Solomonoff, Ray



E-print Network

THE DISCOVERY OF ALGORITHMIC PROBABILITY Ray J. Solomonoff Royal Holloway, University of London will describe a voyage of discovery -- the discovery of Algorithmic Probability. But before I describe, the motivation is discovery itself -- the joy of "going where no one has gone before" -- the excitement

Solomonoff, Ray


DAU StatRefresher: Probability  

NSDL National Science Digital Library

These tutorials, hosted by George Mason University, on probability cover basic probability, random variables, expectations, and distributions. Each lesson provides a definition, the concepts behind each theory and then exercises for students to practice these concepts. This is just one set of concepts in a much larger repository of lessons.



Probability and complex quantum trajectories  

SciTech Connect

It is shown that in the complex trajectory representation of quantum mechanics, the Born's {psi}*{psi} probability density can be obtained from the imaginary part of the velocity field of particles on the real axis. Extending this probability axiom to the complex plane, we first attempt to find a probability density by solving an appropriate conservation equation. The characteristic curves of this conservation equation are found to be the same as the complex paths of particles in the new representation. The boundary condition in this case is that the extended probability density should agree with the quantum probability rule along the real line. For the simple, time-independent, one-dimensional problems worked out here, we find that a conserved probability density can be derived from the velocity field of particles, except in regions where the trajectories were previously suspected to be nonviable. An alternative method to find this probability density in terms of a trajectory integral, which is easier to implement on a computer and useful for single particle solutions, is also presented. Most importantly, we show, by using the complex extension of Schrodinger equation, that the desired conservation equation can be derived from this definition of probability density.

John, Moncy V. [Department of Physics, St. Thomas College, Kozhencherry, Pathanamthitta, Kerala 689 641 (India)], E-mail:



The Probabilities of Conditionals Revisited  

ERIC Educational Resources Information Center

According to what is now commonly referred to as "the Equation" in the literature on indicative conditionals, the probability of any indicative conditional equals the probability of its consequent of the conditional given the antecedent of the conditional. Philosophers widely agree in their assessment that the triviality arguments of…

Douven, Igor; Verbrugge, Sara



Immediate maxillary denture base extension for posterior palatal seal.  


A procedure for extension of the maxillary denture base for development of a posterior palatal seal is described. The technique involves provisional extension with paraffin wax and adding direct relining resin supported by a silicone putty core. This simple, quick procedure achieves immediate recovery of retention for underextended maxillary dentures without additional laboratory procedures. PMID:10709049

Sato, Y; Hosokawa, R; Tsuga, K; Yoshida, M



Immediate maxillary denture base extension for posterior palatal seal  

Microsoft Academic Search

A procedure for extension of the maxillary denture base for development of a posterior palatal seal is described. The technique involves provisional extension with paraffin wax and adding direct relining resin supported by a silicone putty core. This simple, quick procedure achieves immediate recovery of retention for underextended maxillary dentures without additional laboratory procedures. (J Prosthet Dent 2000;83:371-3.)

Yuuji Sato; Ryuji Hosokawa; Kazuhiro Tsuga; Mitsuyoshi Yoshida



Vertical and torsional VOR in posterior canal occlusion.  


The vertical and torsional vestibulo-ocular reflexes (VOR) were investigated in 3 patients with surgical occlusion of the posterior semicircular canal and 1 patient with singular neurectomy, for treatment of refractory paroxysmal positional vertigo. Stimuli comprised sinusoidal oscillation in the coronal ("roll") and sagittal ("pitch") plane as well as in two oblique planes intermediate between pitch in order to stimulate left anterior + right posterior (LARP) and right anterior + left posterior (RALP) canal pairs separately. One case with left side BPPV was investigated pre and post-operatively. Depression of the vertical and torsional VOR gain was seen 1 week postoperatively when the occluded canal was placed in the optimal plane for stimulation at 1 week postoperatively and subsequently gradually recovered. Recordings in other planes suggested that the contralateral posterior canal was also hypofunctioning, a finding which may explain some residual gait unsteadiness in this case. The other 3 cases who were investigated postoperatively all showed a decrease in downward VOR gain in the "on' direction of the operated canal. The data indicate the specificity of the test procedure and underline the prognostic value of comprehensive pre-operative vestibular assessment. PMID:8749162

Kanayama, R; Bronstein, A M; Gresty, M A; Brookes, G B



Identification of Bayesian posteriors for coefficients of chaos expansions  

E-print Network

: stochastic inversion, identification, Bayesian, maximum likelihood, polynomial chaos, validation, uncertainty the Bayesian paradigm can be applied to formulate and solve the inverse problem. The estimated polynomial chaosIdentification of Bayesian posteriors for coefficients of chaos expansions M. Arnst* a , R. Ghanem

Boyer, Edmond


Posterior Predictive Modeling Using Multi-Scale Stochastic Inverse Parameter  

E-print Network

Posterior Predictive Modeling Using Multi- Scale Stochastic Inverse Parameter Estimates Sean A. Mc Motivation x0 x1 X0,j x2 After Ferreira and Lee, 2007, Multiscale Modeling: A Bayesian Perspective Data = proportion of high conductivity #12;Inversion 4 ~ N(0,) ij = C(xi,xj ) = aexp(- | xi - xj |2 /b2 ) F(x) = 1

Ray, Jaideep


Anomalous atlantoaxial portions of vertebral and posterior inferior cerebellar arteries  

Microsoft Academic Search

In a review of the vertebral angiograms of 300 patients free from disease at the craniovertebral junction, we found atlantoaxial arterial anomalies in 2,3%. These were: 2 cases in which the vertebral artery ran in the spinal canal below C1, 3 cases of duplication of the vertebral artery above and below C1, and 2 cases of origin of the posterior

K. Tokuda; K. Miyasaka; H. Abe; S. Abe; H. Takei; S. Sugimoto; M. Tsuru



Spasticity in Cerebral Palsy and the Selective Posterior Rhizotomy Procedure  

Microsoft Academic Search

A review of the selective posterior rhizotomy procedure for reduction of spasticity in cerebral palsy is presented. The history of the procedure, selection of patients, operative technique, and results are described. The neurophysiologic basis for spasticity is considered, as well as the role of spasticity in the complex motor disorder of cerebral palsy. Cerebral palsy is a multifaceted disorder of

Warwick J. Peacock; Loretta A. Staudt



Pathological and haematological aspects of posterior fossa haemangioblastomata.  

PubMed Central

A retrospective study has been carried out on 67 patients harbouring 78 posterior fossa haemangioblastomata. The site, macroscopic nature, and histological features are described, and correlations sought with the degree of erythrocytosis in the peripheral blood. The problems of aetiology are discussed and a single hypothesis advanced. Images PMID:1171159

Jeffreys, R



Posterior concentration rates for infinite dimensional exponential families  

E-print Network

. Consistency of the posterior distribution is admitted as a minimal requirement, both from a subjectivist of log f assumed to be square- integrable. Wavelets are localized in both time and frequency whereas unconditional bases of periodized Sobolev spaces W where is the smoothness parameter. Wavelet expansions of any

Paris-Sud XI, Université de


Posterior concentration rates for infinite dimensional exponential families  

E-print Network

. Consistency of the posterior distribution is admitted as a minimal requirement, both from a subjectivist to families of priors on F built from Fourier and wavelet expansions of log f assumed to be square- integrable in frequency. We recall that Fourier bases constitute unconditional bases of periodized Sobolev spaces W where

Rivoirard, Vincent.


Posterior Predictive Model Checking for Multidimensionality in Item Response Theory  

ERIC Educational Resources Information Center

If data exhibit multidimensionality, key conditional independence assumptions of unidimensional models do not hold. The current work pursues posterior predictive model checking, a flexible family of model-checking procedures, as a tool for criticizing models due to unaccounted for dimensions in the context of item response theory. Factors…

Levy, Roy; Mislevy, Robert J.; Sinharay, Sandip



Clinical evaluation and treatment of posterior impingement in dancers.  


Os trigonum impingement is a frequent cause of posterior ankle pain in ballet dancers because they need extreme plantar flexion during the execution of relevé in demipointe and en pointe positions. Clinical examination and standard and modified x-rays should be carried out to clearly identify the site and entity of the impingement. If a posterior impingement is clinically diagnosed, standard and modified magnetic resonance imaging should be also performed. From September 2005 to September 2006, we considered 186 young trainee ballet dancers. Twelve suffered from posterior ankle pain, and six of these had os trigona. We treated all the ballet dancers nonoperatively, and nine of them had good results. Conservative treatment failed in only three cases after 1-4 mos of physical and medical therapies, and, in these cases, good results were obtained through surgical excision of the accessory ossicle. Modified x-ray and magnetic resonance imaging help to determine the site and entity of the posterior impingement. If this is properly diagnosed, good results can be obtained through a nonoperative approach in a majority of cases. PMID:18617858

Albisetti, Walter; Ometti, Marco; Pascale, Valerio; De Bartolomeo, Omar



Schwannoma of the posterior tibial nerve case study.  


Background : Schwannomas are rare, slow-growing, benign tumors consisting of Schwann cells. They may cause pressure along a bony structure, resulting in increased pain and discomfort. Less than 1% of schwannomas become malignant, and localization in the foot is uncommon (2%-3% of reported cases). Methods : We present a case of a schwannoma of a branch of the posterior tibial nerve sheath. The goal is to assist in recognition, diagnosis, and treatment of schwannoma in the foot and ankle. This is a case of a 51-year-old male soccer player with a soft-tissue mass along the medial ankle at the tarsal tunnel area with an insidious onset (2 years). Physical examination revealed a 3.0 × 2.5-cm mass; magnetic resonance imaging confirmed location, size, and depth. Results : Surgical resection of the soft-tissue mass was performed under general anesthesia. The mass was found to be superior to the flexor retinaculum and attached by a small nerve branch of the posterior tibial nerve that traveled through the flexor retinaculum. A tissue specimen was sent to the pathology laboratory, and a schwannoma was confirmed histologically. Conclusions : Schwannomas can occur after trauma, especially if the posterior tibial nerve or its branches are affected intrinsically or extrinsically, leading to discomfort, pain, and numbness along the tarsal tunnel. Also, unique to this case, a schwannoma may occur along the small branches of the posterior tibial nerve and present anatomically superior to the flexor retinaculum. PMID:25275747

Judd, Tanya; Jones, Taunna; Thornberry, Lauren



Tibial inlay for posterior cruciate ligament reconstruction: a systematic review.  


Although no consensus has been reached regarding the management of PCL deficiency, in vitro and in vivo studies have investigated whether the tibial inlay technique restores the anatomical site of insertion of the PCL, prevents elongation, stretching, graft failure, and improves long-term PCL stability. A systematic search using PubMed, Ovid, the Cochrane Reviews, and Google Scholar databases using 'posterior cruciate ligament tear', 'Tibial inlay technique' and 'posterior cruciate ligament reconstruction' as keywords identified 71 publications, of which 10 were relevant to the topic, and included a total of 255 patients. The tibial inlay technique restores the anatomic insertion site of the PCL, eliminates the killer turn effect, and places the graft at lower potential risk for abrasion and subsequent rupture. It has the disadvantages of increased operating time and risk to the posterior neurovascular structures. There was no evidence of an association between outcome results and Coleman methodology score, but the Coleman methodology scores correlated positively with the level-of-evidence rating. The methodological quality of the studies included has not improved over the years. Given the few reported published findings, we cannot ascertain whether this procedure may provide a consistent alternative to commonly used PCL surgical strategies. The lack of published randomized clinical trials and few reported findings did not allow to ascertain whether the tibial inlay for posterior cruciate ligament reconstruction may provide a consistent alternative to commonly used PCL surgical strategies and to demonstrate procedure efficacy. PMID:20226678

Papalia, Rocco; Osti, Leonardo; Del Buono, Angelo; Denaro, Vincenzo; Maffulli, Nicola



Visual outcome following posterior capsule rupture during cataract surgery  

Microsoft Academic Search

AIMTo determine the relative risk of a poor visual outcome following posterior capsule rupture during cataract surgery.METHODSProspective data were collected on consecutive eyes undergoing cataract extraction. The patient's age, preoperative visual acuity, ocular comorbidity, grade of surgeon, and operative complications were documented. The best spectacle corrected visual acuity was recorded at discharge from the hospital service.RESULTSFrom a total of 1533

Alexander Ionides; Darwin Minassian; Stephen Tuft



A technical variation of posterior chamber IOL implantation.  


In posterior chamber intraocular lens (IOL) implantation, one of the most delicate phases is placing the loops in the capsular bag or in the ciliary sulcus. We describe a technique to simplify the phase of IOL insertion by tying the superior loop with a nylon suture. No changes to the lens and no special instruments are required. PMID:3050672

Recupero, S M; Fioravanti, W; Contestabile, M T



Cataract progression and treatment following posterior lamellar keratoplasty  

Microsoft Academic Search

Purpose: To describe the development and treatment of cataracts following posterior lamellar keratoplasty (PLK) in phakic eyes with Fuchs' endothelial dystrophy.Setting: Price Vision Group, Indianapolis, Indiana, USA.Methods: A retrospective chart review was performed on 47 PLK cases performed by a single surgeon between June 2001 and December 2002 in a tertiary care setting. Four of the eyes were phakic at

Marianne O Price; Francis W Price



Prevalence of sinus augmentation associated with maxillary posterior implants.  


Pneumatization of the maxillary sinus limits the quantity of alveolar bone available for implant placement and may result in a lack of primary stability and difficulty in achieving osseointegration. The purpose of this study was to retrospectively analyze a group of patients who had implants placed in the posterior maxilla, calculate the prevalence of sinus augmentation, and identify factors related to sinus augmentation. With institutional review board approval, dental records from a population of patients who had implants placed in the maxillary posterior region between January 2000 and December 2004 were used to create a database. Independent variables were classified as continuous (age of the patient at stage 1 implant surgery [S1], time between extraction and S1, time between extraction and sinus augmentation, and time between sinus augmentation and S1) and categorical (gender, implant failure, American Society of Anesthesiologists system classification, smoking, osteoporosis, residual crestal bone height, implant position, implant proximity, prostheses type, and implant diameter and length). The dependent variable was the incidence of a sinus augmentation procedure. Simple logistic regression was used to assess the influence of each factor on the presence of sinus augmentation (P < .05). The final database included 502 maxillary posterior implants with an overall survival rate of 93.2% over a mean follow-up period of 35.7 months. Of 502 implants, 272 (54.2%) were associated with a sinus augmentation procedure. Among variables, residual crestal bone height (P < .001), implant position (P < .001), implant proximity (P < .001), prosthesis type (P < .001), implant failure (P < .01), and implant diameter (P < .01), were statistically associated with sinus augmentation. Within the limitations of this retrospective study, the results suggest that more than half (54.2%) of the maxillary posterior implants were involved with a sinus augmentation procedure. The prevalence of sinus augmentation increased with decreased residual crestal bone height, more posterior implant locations, and complete or partial edentulism. Sinus augmentation was significantly associated with implant failure and wide implants. PMID:21651386

Seong, Wook-Jin; Barczak, Michael; Jung, Jae; Basu, Saonli; Olin, Paul S; Conrad, Heather J



Axial Spondylectomy and Circumferential Reconstruction via a Posterior Approach  

PubMed Central

Background Spinal metastases of the second cervical vertebra are a subset of tumors that is particularly difficult to address surgically. Previously described techniques require highly morbid circumferential dissection posterior to the pharynx for resection and reconstruction. Objective To perform a biomechanical analysis of instrumented reconstruction configurations used after axial spondylectomy and demonstrate safe use of a novel construct in a patient case report. Methods Several different published and novel reconstruction configurations were inserted into 7 occipitocervical spines that underwent axial spondylectomy. A biomechanical analysis of the constructs’ stiffness in flexion and extension, lateral bending, and rotation was performed. A patient then underwent a posterior-only approach for axial spondylectomy and circumferential reconstruction. Results Biomechanical analysis of different constructs demonstrated that anterior column reconstruction with bilateral cages spanning C1 lateral mass to C3 facet in combination with occipitocervical instrumentation was superior in flexion-extension and equivalent in lateral bending and rotation to currently used constructs. In the patient in which this construct was placed via a posterior-only approach for axial spondylectomy and instrumentation, the patient remained at neurological baseline and demonstrated no recurrence of local disease or failure of instrumentation to date. Conclusion When comparing C1 lateral mass to C3 facet bilateral cage plus occipitocervical instrumentation to existing anterior and posterior constructs, this novel reconstruction is biomechanically equivalent if not superior in performance. In a patient, the posterior-only approach for C2 spondylectomy with the novel reconstruction was safe, durable, and avoided the morbidity of the anterior approach. PMID:23149951

Jandial, Rahul; Kelly, Brandon; Bucklen, Brandon; Khalil, Saif; Chen, Mike Y.



Arthroscopic isolated posterior labral repair in rugby players  

PubMed Central

Background The shoulder is the second most frequently injured joint after the knee in rugby players and labral tears appear to be common. There is limited data available in the literature regarding the mechanisms of posterior labral injury in rugby players and the management of these injuries. Objective The aim of this study is to report the clinical presentation, arthroscopic findings, surgical technique for repair, and the functional outcome in elite English rugby players with isolated posterior labral injuries. Study Design Case series (level IV evidence) Materials and Methods Over a 5-year period we surgically treated 142 elite rugby players, of whom 11 (7.8%) had isolated posterior labral injuries. All these 11 patients had significant contact injury. Only three (24%) patients had a true posterior shoulder dislocation. Pre- and postoperative assessment included Constant score, Oxford shoulder score, and Oxford instability score. We also assessed the time taken to return to preinjury level of fitness and the complications of surgery. Results Average follow-up was for 32 months (range 17–54 months). The mean Constant score improved from 66 to 99. The Oxford score indicated improvement, decreasing from 33 to 18; similarly, the Oxford instability score also decreased from 52.2 to 12.3. Return to playing rugby at peak level was at a mean of 4.3 months after arthroscopic repair. Conclusion Successful clinical results and rapid return to play can be achieved by appropriate early arthroscopic repair and supervised accelerated rehabilitation for posterior labral tears in elite rugby players. PMID:20616949

Badge, Ravi; Tambe, Amol; Funk, Lennard



Robotic Posterior Mitral Leaflet Repair: Neochordal versus Resectional Techniques  

PubMed Central

Background Resectional techniques are the established method of posterior mitral valve leaflet repair for degenerative disease; however, use of neochordae in a robotically assisted approach is gaining acceptance because of its versatility for difficult multi-segment disease. The purposes of this study were to compare the versatility, safety, and effectiveness of neochordal vs. resectional techniques for robotic posterior mitral leaflet repair. Methods From 12/2007 to 7/2010, 334 patients underwent robotic posterior mitral leaflet repair for degenerative disease by a resectional (n=248) or neochordal (n=86) technique. Outcomes were compared unadjusted and after propensity score matching. Results Neochordae were more likely to be used than resection in patients with two (28% vs. 13%, P=.002) or three (3.7% vs. 0.87%, P=.08) diseased posterior leaflet segments. Three resection patients (0.98%) but no neochordal patient required reoperation for hemodynamically significant systolic anterior motion (SAM). Residual mitral regurgitation (MR) at hospital discharge was similar for matched neochordal vs. resection patients (P=.14) (MR 0+, 82% vs. 89%; MR 1+, 14% vs. 8.2%; MR 2+, 2.3% vs. 2.6%; one neochordal patient had 4+ MR and was reoperated). Among matched patients, postoperative mortality and morbidity were similarly low. Conclusion Compared with a resectional technique, robotic posterior mitral leaflet repair with neochordae is associated with shorter operative times and no occurrence of SAM. The versatility, effectiveness, and safety of this repair make it a good choice for patients with advanced multi-segment disease. PMID:23103008

Mihaljevic, Tomislav; Pattakos, Gregory; Gillinov, A. Marc; Bajwa, Gurjyot; Planinc, Mislav; Williams, Sarah J.; Blackstone, Eugene H.



Anterior and posterior corneal stroma elasticity assessed using nanoindentation  

PubMed Central

Corneal biomechanics is an essential parameter for developing diagnostic and treatment methods of corneal-related diseases. It is widely accepted that corneal mechanical strength stems from the stroma's collagenous composition. However, more comprehensive insight into the mechanical properties within the stroma is needed to improve current corneal diagnostic and treatment techniques. The purpose of this study was to perform elasticity characterization of anterior and posterior stromal regions of human corneas using atomic force microscopy (AFM). Nine pairs of human whole globes were placed in 20% Dextran solution, cornea side down, to restore the corneal thickness to physiological levels (400-600?m). The epithelium and Bowman's membrane were removed from all eyes. Anterior stromal AFM elasticity testing was then performed on left (OS) eyes. Additional stroma was removed from right (OD) eyes to allow posterior stromal measurements at a depth of 50% of the original thickness. All experiments were performed with corneas submerged in 15% Dextran to maintain corneal hydration. The results of the study showed that the Young's modulus of elasticity of the anterior stroma (average: 281 ± 214kPa; range: 59-764kPa) was significantly higher than that of the posterior stroma (average: 89.5 ± 46.1kPa; range: 29-179kPa) (p=0.014). In addition, a linear relationship was found between the posterior stromal elasticity and anterior stromal elasticity (p=0.0428). On average, the elasticity of the posterior stroma is 39.3% of the anterior stroma. In summary, there appears to be an elasticity gradient within the corneal stroma, which should be considered in the design and development of corneal diagnostic and treatment methods to enhance efficacy. PMID:23800511

Dias, Janice; Ziebarth, Noel M.



The relation between pogonion advancement and posterior maxillary impaction.  


Controversy exists about the relation between the amount of posterior maxillary impaction and pogonion (P) advancement. The aims of the current study were to (1) propose a formula to predict the amount of P advancement due to posterior maxillary impaction surgery, (2) predict the amount of posterior maxillary impaction by means of a formula to achieve the best facial harmony, and (3) identify the compatibility between proposed formulas and the actual resultant mandibular position after posterior maxillary impaction surgery. For obtaining the formulas, 2 cephalograms were taken from 1 patient in centric occlusion and rest position. Afterward, mandibular rotational center was obtained by superimposing the cephalograms; by the help of which the 2 formulas were obtained. To check the reliability of the formulas, 10 patients with the mean age of 21 +/- 1.5 years who had undergone posterior maxillary impaction were selected. The presurgical and postsurgical cephalograms of patients were obtained. These cephalograms were superimposed to find the center of mandibular rotation. Pearson correlation coefficient test was used to evaluate the relation between the suggested formulas and the clinical data. This test showed that there were significant correlations between maxillary impaction and P advancement in both the formulas and clinical evaluation. This correlation (r) was 0.993 (P < 0.001) based on formulas and r = 0.806 (P < 0.005) based on tracing. This study showed that the amounts of anterior facial height reduction and P advancement were almost the same, and the anterior facial height was reduced 1.5 times more than the amount of maxillary impaction. PMID:19349906

Jamilian, Abdolreza; Showkatbakhsh, Abdolrahman; Gholami, Dariush; Kamali, Zinat



An unusual amniotic rupture sequence with thoracoabdominal restricting band, low-set posterior hairline, and trapezius contracture.  


Amniotic rupture sequence is associated with defects of variable severity and at different sites. Analysis of the literature reveals difficulties in the classification, which, in addition to uncertainties surrounding its causes, make diagnosis of unusual presentations rather difficult. We present an unusual case of a thoracoabdominal restrictive band from the umbilicus to a low-set posterior hairline with severe trapezius contracture, sternoclavicular dislocation, and no associated craniofacial or limb abnormalities. Amnion rupture sequence with adhesion band seems to be the most probable cause of this rare combination of anomalies. PMID:20818258

Atiyeh, Bishara S; Moucharafieh, Ramzi



REMAP: Recursive Estimation and Maximization of A Posteriori Probabilities - Application to Transition-Based Connectionist Speech Recognition  

Microsoft Academic Search

In this paper, we describe the theoretical formulation of REMAP, an approach for the training and estimation of posterior probabilities using a recursive algorithm that is reminiscent of the EM (Expectation Maximization) algorithm (Dempster et al. 1977) for the estimation of data likelihoods. Although very general, the method is developed in the context of a statistical model for transition-based speech

Yochai Konig; Hervé Bourlard; Nelson Morgan



Asymptomatic Solitary Cerebral Metastasis From Papillary Carcinoma Thyroid: 131I SPECT/CT for Accurate Staging.  


Isolated asymptomatic brain metastasis in papillary carcinoma thyroid (PCT) is extremely rare. We here present such a case of a 48-year-old woman with PCT. SPECT/CT localized the I radiotracer concentration seen on whole-body scan in this patient to the right posterior parietal cortex, suggesting brain metastasis. Contrast-enhanced MRI and F-FDG PET/CT confirmed the diagnosis and the patient was taken for gamma-knife radiosurgery. I SPECT/CT in this case accurately restaged the patient by detecting asymptomatic isolated brain metastasis and correctly directed the management strategy. PMID:24566406

Jain, Tarun Kumar; Karunanithi, Sellam; Sharma, Punit; Vijay, Maneesh Kumar; Ballal, Sanjana; Bal, Chandrasekhar



Failure probability under parameter uncertainty.  


In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications. PMID:21175720

Gerrard, R; Tsanakas, A



Anomalous vertebral and posterior communicating arteries as a risk factor in instrumentation of the posterior cervical spine.  


We investigated the incidence of anomalies in the vertebral arteries and Circle of Willis with three-dimensional CT angiography in 55 consecutive patients who had undergone an instrumented posterior fusion of the cervical spine. We recorded any peri-operative and post-operative complications. The frequency of congenital anomalies was 30.9%, abnormal vertebral artery blood flow was 58.2% and vertebral artery dominance 40%. The posterior communicating artery was occluded on one side in 41.8% of patients and bilaterally in 38.2%. Variations in the vertebral arteries and Circle of Willis were not significantly related to the presence or absence of posterior communicating arteries. Importantly, 18.2% of patients showed characteristic variations in the Circle of Willis with unilateral vertebral artery stenosis or a dominant vertebral artery, indicating that injury may cause lethal complications. One patient had post-operative cerebellar symptoms due to intra-operative injury of the vertebral artery, and one underwent a different surgical procedure because of insufficient collateral circulation. Pre-operative assessment of the vertebral arteries and Circle of Willis is essential if a posterior spinal fusion with instrumentation is to be carried out safely. PMID:24692624

Nagahama, K; Sudo, H; Abumi, K; Ito, M; Takahata, M; Hiratsuka, S; Kuroki, K; Iwasaki, N



On quantum vs. classical probability  

E-print Network

Quantum theory shares with classical probability theory many important properties. I show that this common core regards at least the following six areas, and I provide details on each of these: the logic of propositions, symmetry, probabilities, composition of systems, state preparation and reductionism. The essential distinction between classical and quantum theory, on the other hand, is shown to be joint decidability versus smoothness; for the latter in particular I supply ample explanation and motivation. Finally, I argue that beyond quantum theory there are no other generalisations of classical probability theory that are relevant to physics.

Jochen Rau



What Clinicians Can Offer: Assessing and Communicating Probabilities for Individual Patient Decision Making  

Microsoft Academic Search

Accurate diagnostic and prognostic probabilities are important for physicians and their patients because of their impact on decisions. For individual patient decision making, physicians have to rely on their own judgement. Research has shown that physicians’ probability assessments are often not of high quality and that a variety of factors have a detrimental influence on their judgements. Using a formula

Danielle R. M. Timmermans



Impact of MCNP unresolved resonance probability-table treatment on uranium and plutonium benchmarks  

SciTech Connect

Versions of MCNP up through and including 4B have not accurately modeled neutron self-shielding effects in the unresolved resonance energy region. Recently, a probability-table treatment has been incorporated into a developmental version of MCNP. This paper presents MCNP results for a variety of uranium and plutonium critical benchmarks, calculated with and without the probability-table treatment.

Mosteller, R.D.; Little, R.C.



Chiari I malformation associated with premature unilateral closure of the posterior intraoccipital synchondrosis in a preterm infant.  


The authors report a case of a preterm infant at 29 weeks of gestation who gradually developed a Chiari malformation Type I (CM-I) with hydrocephalus due to a premature unilateral fusion of the posterior intraoccipital synchondrosis. Brain ultrasonography results in the 1st week of life were normal. Follow-up ultrasonography showed progressive development of triventricular hydrocephalus. Brain MRI demonstrated the presence of a CM-I and a deformation of the occipital bone. A complementary CT scan was obtained, showing a closure of the right posterior intraoccipital synchondrosis, resulting in a deformation of the posterior cranial fossa. This case shows the close relationship between a malformation of the skull base and the secondary development of a brain malformation. The authors discuss the anatomy of the occipital bone and suggest a probable theory for the premature closure of this synchondrosis and the consequent development of a CM-I. The originality of this case lies in the observation of the natural history of a brain malformation in a preterm infant. PMID:23581638

Kanavaki, Aikaterini; Jenny, Benoit; Hanquinet, Sylviane



Electrofishing capture probability of smallmouth bass in streams  

USGS Publications Warehouse

Abundance estimation is an integral part of understanding the ecology and advancing the management of fish populations and communities. Mark-recapture and removal methods are commonly used to estimate the abundance of stream fishes. Alternatively, abundance can be estimated by dividing the number of individuals sampled by the probability of capture. We conducted a mark-recapture study and used multiple repeated-measures logistic regression to determine the influence of fish size, sampling procedures, and stream habitat variables on the cumulative capture probability for smallmouth bass Micropterus dolomieu in two eastern Oklahoma streams. The predicted capture probability was used to adjust the number of individuals sampled to obtain abundance estimates. The observed capture probabilities were higher for larger fish and decreased with successive electrofishing passes for larger fish only. Model selection suggested that the number of electrofishing passes, fish length, and mean thalweg depth affected capture probabilities the most; there was little evidence for any effect of electrofishing power density and woody debris density on capture probability. Leave-one-out cross validation showed that the cumulative capture probability model predicts smallmouth abundance accurately. ?? Copyright by the American Fisheries Society 2007.

Dauwalter, D.C.; Fisher, W.L.



Probability and Statistics Object Library  

NSDL National Science Digital Library

This library contains a plethora of downloadable applets and the components of the applets for use by teachers and students of probability and statistics. These objects (both executable files and source code) can be downloaded, modified if desired, and reused.

Siegrist, Kyle



The Probabilities of Unique Events  

PubMed Central

Many theorists argue that the probabilities of unique events, even real possibilities such as President Obama's re-election, are meaningless. As a consequence, psychologists have seldom investigated them. We propose a new theory (implemented in a computer program) in which such estimates depend on an intuitive non-numerical system capable only of simple procedures, and a deliberative system that maps intuitions into numbers. The theory predicts that estimates of the probabilities of conjunctions should often tend to split the difference between the probabilities of the two conjuncts. We report two experiments showing that individuals commit such violations of the probability calculus, and corroborating other predictions of the theory, e.g., individuals err in the same way even when they make non-numerical verbal estimates, such as that an event is highly improbable. PMID:23056224

Khemlani, Sangeet S.; Lotstein, Max; Johnson-Laird, Phil



Probability in a Primary School  

NSDL National Science Digital Library

This reference material, created by Philip Sherwood, provides various activities and tasks, which help elementary aged children understand the concepts of probability. The author has a nice series of diagrams intertwined within the text to help illustrate these concepts.

Sherwood, Philip



Error Correcting Codes Probability Propagation  

E-print Network

communication? We would like to achieve virtually error-free communication. e.g., an error probability of #24 by Gallager, but were then generally forgotten by the coding theory community. #12; Theoretical result: Low

MacKay, David J.C.


Logical, conditional, and classical probability  

E-print Network

The propositional logic is generalized on the real numbers field. the logical function with all properties of the classical probability function is obtained. The logical analog of the Bernoulli independent tests scheme is constructed. The logical analog of the Large Number Law is deduced from properties of these functions. The logical analog of thd conditional probability is defined. Consistency encured by a model on a suitable variant of the nonstandard analysis.

G. A. Quznetsov



Formalization of Continuous Probability Distributions  

Microsoft Academic Search

In order to overcome the limitations of state-of-the-art simulation based probabilis- tic analysis, we propose to perform probabilistic analysis within the environment of a higher-order-logic theorem prover. The foremost requirement for conducting such analysis is the formalization of probability distributions. In this report, we present a methodology for the formalization of continuous probability distributions for which the inverse of the

Osman Hasan; Sofiène Tahar



Joint probabilities and quantum cognition  

E-print Network

In this paper we discuss the existence of joint probability distributions for quantum-like response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

J. Acacio de Barros



Analytic bounds on transmission probabilities  

SciTech Connect

We develop some new analytic bounds on transmission probabilities (and the related reflection probabilities and Bogoliubov coefficients) for generic one-dimensional scattering problems. To do so we rewrite the Schroedinger equation for some complicated potential whose properties we are trying to investigate in terms of some simpler potential whose properties are assumed known, plus a (possibly large) 'shift' in the potential. Doing so permits us to extract considerable useful information without having to exactly solve the full scattering problem.

Boonserm, Petarpa, E-mail: [Department of Mathematics, Faculty of Science Chulalongkorn University, Phayathai Rd., Pathumwan Bangkok 10330 (Thailand); Visser, Matt, E-mail: [School of Mathematics, Statistics, and Operations Research, Victoria University of Wellington (New Zealand)



Joint probabilities and quantum cognition  

SciTech Connect

In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

Acacio de Barros, J. [Liberal Studies, 1600 Holloway Ave., San Francisco State University, San Francisco, CA 94132 (United States)



Investigation of Key-Player Problem in Terrorist Networks Using Bayes Conditional Probability  

Microsoft Academic Search

\\u000a In Social Network Analysis (SNA) it is quite conventional to employ graph theory concepts for example cut-points and cut-sets\\u000a or measuring node centralities like betweenness, degree and closeness to highlight important actors in the network. However,\\u000a it is also believed that most of these measures alone are inadequate for investigating terrorist\\/covert networks. In this\\u000a paper we compute posterior probability using

D. M. Akbar Hussain


Pretty Purple Probabilities and Data Analysis!  

NSDL National Science Digital Library

Plump Probability Problems need Played! The probability of the cards while playing the Probability Game! Find the probability of landing on each color, changing the parts size, when you spin the Probability Spinner! If you want a definition of any probability term.. click the word Definition ...

Nieman, Ms.



Intrinsic and extrinsic factors in the mechanism of neurulation: effect of curvature of the body axis on closure of the posterior neuropore.  


Neurulation has been suggested to involve both factors intrinsic and extrinsic to the neuroepithelium. In the curly tail (ct) mutant mouse embryo, final closure of the posterior neuropore is delayed to varying extents resulting in neural tube defects. Evidence was presented recently (Brook et al., 1991 Development 113, 671-678) to suggest that enhanced ventral curvature of the caudal region is responsible for the neurulation defect, which probably originates from an abnormally reduced rate of cell proliferation affecting the hindgut endoderm and notochord, but not the neuroepithelium (Copp et al., 1988, Development 104, 285-295). This axial curvature probably generates a mechanical stress on the posterior neuropore, opposing normal closure. We predicted, therefore, that the ct/ct posterior neuropore should be capable of normal closure if the neuropore should be capable of normal closure if the neuroepithelium is isolated from its adjacent tissues. This prediction was tested by in vitro culture of ct/ct posterior neuropore regions, isolated by a cut caudal to the 5th from last somite. In experimental explants, the neuroepithelium of the posterior neuropore, together with the contiguous portion of the neural tube, were separated mechanically from all adjacent non-neural tissues. The posterior neuropore closed in these explants at a similar rate to isolated posterior neuropore regions of non-mutant embryos. By contrast, control ct/ct explants, in which the caudal region was isolated but the neuroepithelium was left attached to adjacent tissues, showed delayed neurulation. To examine further the idea that axial curvature may be a general mechanism regulating neurulation, we cultured chick embryos on curved substrata in vitro. Slight curvature of the body axis (maximally 1 degree per mm axial length), of either concave or convex nature, resulted in delay of posterior neuropore closure in the chick embryo. Both incidence and extent of closure delay correlated with the degree of curvature that was imposed. We propose that during normal embryogenesis the rate of neurulation is related to the angle of axial curvature, such that experimental alterations in curvature will have differing effects (either enhancement or delay of closure) depending on the angle of curvature at which neurulation normally occurs in a given species, or at a given level of the body axis. PMID:8325240

van Straaten, H W; Hekking, J W; Consten, C; Copp, A J




PubMed Central

Posterior internal impingement (PII) of the glenohumeral joint is a common cause of shoulder complex pain in the overhead athlete. This impingement is very different from standard outlet impingement seen in shoulder patients. Internal impingement is characterized by posterior shoulder pain when the athlete places the humerus in extreme external rotation and abduction as in the cocking phase of pitching or throwing. Impingement in this position occurs between the supraspinatus and or infraspinatus and the glenoid rim. Understanding regarding this pathology continues to evolve. Definitive understanding of precipitating factors, causes, presentation and methods of treatment have yet to be determined. A high index of suspicion should be used when attempting to make this diagnosis. This current concepts review presents the current thinking regarding pathophysiology, evaluation, and treatment of this condition. Level of Evidence: 5 PMID:23593557

Grant-Nierman, Meggan; Lucas, Brennen



Endovascular treatment of a true posterior communicating artery aneurysm  

PubMed Central

Background: Posterior communicating artery (PCoA) aneurysms are most commonly located at the junction of the internal carotid artery and the PCoA. “True” PCoA aneurysms, which originate from the PCoA itself, are rarely encountered. Most previously reported cases were treated surgically mainly before the endovascular option became available. Case Description: A 53-year-old male presented with sudden onset of right hemiparesis and aphasia. Left middle cerebral artery stroke was diagnosed. Further studies revealed a 3 mm left PCoA aneurysm arising from the PCoA itself, attached to neither the internal carotid artery nor the posterior cerebral artery. Endovascular treatment was performed and the aneurysm was coiled completely. Conclusion: Technical advances in endovascular interventional technology have permitted an additional approach to these lesions. The possible endovascular significance of the treatment of true PCoA aneurysms is discussed.

Munarriz, Pablo M.; Castaño-Leon, Ana M.; Cepeda, Santiago; Campollo, Jorge; Alén, Jose F.; Lagares, Alfonso



A case of hypospadias, anterior and posterior urethral valves  

PubMed Central

This report outlines the case of a 3-year-old boy whose initial presentation was that of asymptomatic hypertension (lowest recording 148/90), found at preoperative check prior to stage 2-correction surgery for distal hypospadias. Upon diagnosis of true hypertension, an ultrasound of the child's renal tract showed evidence of marked hydronephrosis and calyceal dilatation. On the background of deteriorating renal function (Urea 25.5 and Creatinine 188), a Micturating Cystourethrogram was performed, demonstrating posterior urethral dilatation. With difficulties controlling blood pressure, the child was transferred to Urology care, where resection of a posterior urethral valve (PUV) was undertaken. Despite this, renal function deteriorated further and re-cystoscopy identified an anterior urethral valve (AUV), which was also resected. Renal function, although improved, remains poor and blood pressure is controlled with two anti-hypertensives. To the publisher's knowledge, the association between hypospadias, PUVs and AUVs is as yet undocumented. PMID:24964414

Carvell, James; Mulik, Roopa



A case of hypospadias, anterior and posterior urethral valves.  


This report outlines the case of a 3-year-old boy whose initial presentation was that of asymptomatic hypertension (lowest recording 148/90), found at preoperative check prior to stage 2-correction surgery for distal hypospadias. Upon diagnosis of true hypertension, an ultrasound of the child's renal tract showed evidence of marked hydronephrosis and calyceal dilatation. On the background of deteriorating renal function (Urea 25.5 and Creatinine 188), a Micturating Cystourethrogram was performed, demonstrating posterior urethral dilatation. With difficulties controlling blood pressure, the child was transferred to Urology care, where resection of a posterior urethral valve (PUV) was undertaken. Despite this, renal function deteriorated further and re-cystoscopy identified an anterior urethral valve (AUV), which was also resected. Renal function, although improved, remains poor and blood pressure is controlled with two anti-hypertensives. To the publisher's knowledge, the association between hypospadias, PUVs and AUVs is as yet undocumented. PMID:24964414

Carvell, James; Mulik, Roopa



Extended indications for robotic surgery for posterior mediastinal tumors.  


Previously, we evaluated use of the da Vinci Surgical System for anterior and middle mediastinal tumors in clinical cases, focusing on feasibility, safety, and appropriate settings. In this study, we evaluated extending the indications for robotic surgical treatment of posterior mediastinal tumors to include those located adjacent to the upper vertebrae or aorta. Three patients with mediastinal tumors located immediately adjacent to the vertebrae or aorta, underwent resection with the da Vinci Surgical System. All resected tumors were benign histologically. Robotic surgery enabled treatment of tumors located in the posterior mediastinum, which are very difficult to reach, making resection with the conventional video-assisted thoracoscopic surgery technique extremely difficult. All procedures were performed safely, smoothly, and extremely precisely. Crucial to the success of these operations were the appropriate placement and angle of the special da Vinci surgical ports in relation to the target and the patient's position, which varied according to the tumor location. PMID:22718720

Kajiwara, Naohiro; Kakihana, Masatoshi; Usuda, Jitsuo; Ohira, Tatsuo; Kawate, Norihiko; Ikeda, Norihiko



Posterior approach for sciatic aneurysm repair - technical note.  


Aneurysm of the persistent sciatic artery is a rare cause of limb ischemia, which is a challenge for both diagnosis and treatment. After successful diagnosis adequate treatment may require skills in open and endovascular surgery. We present a patient with the aneurysm of the persistent sciatic artery treated by bypass procedure with PTFE graft using posterior approach. We named this procedure "dorsal bypass". Detailed explanation of clinical presentation, diagnosis and the surgical procedure is given in this paper. PMID:24003007

Cvetkovic, S; Koncar, I; Dragas, M; Ilic, N; Pejkic, S; Kostic, D; Davidovic, L



Posterior dislocation of the hip while playing basketball  

PubMed Central

Injuries in basketball are usually to the ankles and knees. Dislocation of the hip is usually associated with severe trauma--for example, road traffic accidents. A case is reported here in which a 22 year old club basketball player slipped on landing from a jump shot, forcing him into a side splits position from which he sustained a posterior dislocation of the hip resulting in a sciatic nerve palsy. ????? PMID:9865411

Tennent, T. D.; Chambler, A. F.; Rossouw, D. J.



Internal fixation of femoral neck fractures with posterior comminution  

Microsoft Academic Search

Background and purpose  Internal fixation is a therapeutic mainstay for treatment of undisplaced femoral neck fractures and fractures without posterior\\u000a comminution. The best treatment for unstable and comminuted fractures, however, remains controversial, especially in older\\u000a patients. The present study was designed to assess the utility of the Intertan Nail® (IT) for stabilization of comminuted\\u000a Pauwels type III fractures compared to dynamic

Martin Rupprecht; Lars Grossterlinden; Kai Sellenschloh; Michael Hoffmann; Klaus Püschel; Michael Morlock; Johannes M. Rueger; Wolfgang Lehmann


Posterior reversible encephalopathy syndrome (PRES) in critically ill obstetric patients  

Microsoft Academic Search

ObjectiveTo describe clinical, neuroradiological and evolutionary findings in obstetric patients with posterior reversible encephalopathy syndrome (PRES).DesignRetrospective case series.SettingUniversity intensive care unit (ICU).PatientsFour critically ill patients. Two patients experienced PRES in late postpartum without the classical pre-eclamptic signs. All patients showed impairment of consciousness and epileptic seizures; two of them presented cortical blindness and headache, too. True status epilepticus (SE) occurred

Giuseppe Servillo; Pasquale Striano; Salvatore Striano; Fabio Tortora; Patrizia Boccella; Edoardo De Robertis; Flavia Rossano; Francesco Briganti; Rosalba Tufano



Functional assessment following selective posterior rhizotomy in spastic cerebral palsy  

Microsoft Academic Search

This study used the Pediatric Evaluation of Disability Inventory as a functional assessment tool for children with spastic cerebral palsy undergoing selective posterior rhizotomy. Sixteen patients were followed for 3–12 months following surgery. Improvement in self-care, mobility, and social functional skills were found. Overall, the patients required less caregiver assistance and needed fewer modifications for self-care. The results suggest that

Karen K. Bloom; Gregory B. Nazar



Magnetic resonance properties of hydrogen: imaging the posterior fossa  

Microsoft Academic Search

Posterior fossa scans were performed on five healthy volunteers using a nuclear magnetic resonance (NMR) machine constructed by Thorn-EMI Ltd. Three different NMR scanning sequences were used. In the first, a type of saturation-recovery technique was used to produce images strongly dependent on the density of hydrogen nuclei, but with some dependence on the spin-lattice relaxation time (Tâ). In the

I. R. Young; M. Burl; G. J. Clarke



A case of posterior element fracture in Kummell's disease  

Microsoft Academic Search

Kummell's disease is a rare, delayed posttraumatic collapse of a vertebral body that can occur several months or even years\\u000a after an osteoporotic compression fracture. However, there are few reports of posterior element fractures associated with\\u000a Kummell's disease. A 72-year-old man who had sustained an L1 osteoporotic compression fracture 14 months prior was admitted\\u000a to our institution with incapacitating back pain.

S. W. Kim; H.-S. Kim


Efficient solutions to factored MDPs with imprecise transition probabilities  

Microsoft Academic Search

When modeling real-world decision-theoretic planning problems in the Markov Decision Process (MDP) framework, it is often impossible to obtain a completely accurate estimate of transition probabilities. For example, natural uncertainty arises in the transition specification due to elicitation of MDP transition models from an expert or estimation from data, or non-stationary transition distributions arising from insufficient state knowledge. In the

Karina Valdivia Delgado; Scott Sanner; Leliane Nunes de Barros



Aspects of treatment for posterior heel pain in young athletes.  


Posterior heel pain occurs in young athletes involved in running and jumping. Due to the pain, the child often limits his/her physical activity level, with a possible negative effect on health and well-being. Although numerous research studies have examined the cause and treatment of heel and Achilles tendon pain in adults, there are no randomized clinical trials on treatment in children and adolescents. Therefore, there is limited evidence for how to treat young athletes with this type of complaint. The purpose of this review was to analyze critically and summarize the literature in regards to the cause and treatment of posterior heel pain in young athletes. The various diagnoses and clinical presentations relating to posterior heel and Achilles tendon pain are discussed. The theory and mechanism behind various recommended treatment strategies are also reviewed in the context of use in the young athlete. In summary, it is important to perform a thorough evaluation of each young athlete with heel pain to determine the appropriate diagnosis and to treat the deficits found and allow for a gradual progression to training. However, the recommendations at this time are based on clinical experience and a few retrospective studies, so further well designed prospective studies with validated outcome measures are urgently needed for the young athlete. PMID:24198561

Elengard, Thomas; Karlsson, Jón; Silbernagel, Karin Grävare



Posterior fossa cysts: clinical, neuroradiological and surgical features.  


Various types of neuroimaging investigations were performed in 26 patients with posterior fossa cysts. The results were retrospectively analyzed to facilitate differential diagnosis and clarify indications for surgery. Four major findings were obtained in this study. First, posterior fossa intra-arachnoid cysts were encountered more frequently than expected and were found to be surgically treatable. Second, although IV ventricular cysts were categorized as Dandy-Walker malformation, Dandy-Walker variant, and persistent Blake's pouch in this study, the distinctions of neuroimaging findings between these three types are uncertain. Third, the diagnostic criteria for mega cisterna magna were established, and it was found to be a surgically untreatable condition. Finally, in cases with the following neuroimaging findings, surgery appears to be indicated: (1) occipital bossing or petrosal scalloping with distortion or obliteration of cerebrospinal fluid (CSF) cisterns of the posterior fossa; (2) compression and deformity of the brain surrounding the cyst; (3) radioisotope and/or computed tomography cisternographic findings suggestive of disturbance of intracystic CSF circulation; (4) a non-communicating cyst. PMID:1878871

Arai, H; Sato, K



Posterior minimally invasive plate osteosynthesis for humeral shaft fractures.  


Fractures of the humeral shaft are common. Most of them can be successfully treated without surgery. In some cases, an operative intervention may offer faster and better functional results. One of the major problems with the open plating osteosynthesis is the extensive soft tissue stripping and disruption of periosteal circulation, caused by extensive surgical exposure, resulting in a relatively high rate of nonunion. Minimally invasive plate osteosynthesis (MIPO) techniques were developed to achieve a biologic fixation, although minimizing the complications of an open reduction. The incisions are small and remote from the fracture site to avoid direct fracture exposure. Thereby, MIPO technique obtains, theoretically, higher rates of union, lower infection risk, and decreases the need for bone graft. In the last years, MIPO has gained popularity with satisfactory clinical outcomes in the treatment of long bone fractures, especially in lower extremity. MIPO for humeral shaft fractures, however, could be a surgically dangerous procedure because of the risk of radial nerve injury. It was described by anterior and lateral approach. Humeral middle shaft fractures are possible to treat with a MIPO technique through an anterior, lateral, or a posterior approach. However, when the fracture is near the olecranon fossa, anterior approach is not possible as there is not enough space in the distal fragment to insert the amount of screws required to achieve stability. In this case, the posterior approach may be a good option for treatment. This article describes the MIPO technique through a posterior approach for the treatment of humeral shaft fractures. PMID:24458002

Gallucci, Gerardo; Boretto, Jorge; Vujovich, Andrea; Alfie, Verónica; Donndorff, Agustín; De Carli, Pablo



Automated measurement of anterior and posterior acetabular sector angles  

NASA Astrophysics Data System (ADS)

In this paper, we propose a segmentation algorithm by which anatomical landmarks on the pelvis are extracted from computed tomography (CT) images. The landmarks are used to automatically define the anterior (AASA) and posterior acetabular sector angles (PASA) describing the degree of hip misalignment. The center of each femoral head is obtained by searching for the point at which most intensity gradient vectors defined at edge points intersect. The radius of each femoral head is computed by finding the sphere, positioned at the center of the femoral head, for which the normalized sum of gradient vector magnitudes on the sphere surface is maximal. The anterior and posterior corners of each acetabulum are searched for on a curve representing the acetabulum and defined by dynamic programming. The femoral head centers and anterior and posterior corners are used to calculate the AASA and PASA. The algorithm was applied to CT images of 120 normal subjects and the results were compared to ground truth values obtained by manual segmentation. The mean absolute difference (+/- standard deviation) between the obtained and ground truth values was 1.3 +/- 0.3 mm for the femoral head centers and 2.1 +/- 1.3 degrees for the acetabular angles.

Ibragimov, Bulat; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž



Effect of Schneiderian Membrane Perforation on Posterior Maxillary Implant Survival  

PubMed Central

Background: To assess the survival rate of implants placed in the posterior maxilla by intentionally perforating the Schneiderian membrane and protruding the implant up to 3mm beyond the sinus floor in cases of reduced crestal bone height (CBH). Materials & Methods: 56 patients with reduced CBH received 63 implants in the posterior maxilla. All implants intentionally penetrated the Schneiderian membrane and engaged the sinus floor cortical bone. All patients were followed up and implant survival was assessed at the end of one year post implant restoration. Results: Out of 63 implants, there was only one failure (98.4% Survival rate) after a follow up period of one year. 7 patients experienced mild epistaxis during the immediate post-operative period with no associated implant loss. One patient developed sinusitis secondary to the surgical procedure, which was treated by antibiotic therapy and the patient improved clinically with no associated implant loss. Conclusion: An intentional perforation of the Schneiderian membrane using a 2mm twist drill at the time of implant placement and protrusion of the implant up to 3mm beyond the sinus floor does not alter the stability and outcome of dental implants, one year post-restoration. This could be associated with minor complications ranging from epistaxis to sinusitis, which are manageable. How to cite this article: Nooh N. Effect of Schneiderian Membrane Perforation on Posterior Maxillary Implant Survival. J Int Oral Health 2013; 5(3):28-34. PMID:24155599

Nooh, Nasser



Intensity-Modulated Arc Therapy for Pediatric Posterior Fossa Tumors  

SciTech Connect

Purpose: To compare intensity-modulated arc therapy (IMAT) to noncoplanar intensity-modulated radiation therapy (IMRT) in the treatment of pediatric posterior fossa tumors. Methods and Materials: Nine pediatric patients with posterior fossa tumors, mean age 9 years (range, 6-15 years), treated using IMRT were chosen for this comparative planning study because of their tumor location. Each patient's treatment was replanned to receive 54 Gy to the planning target volume (PTV) using five different methods: eight-field noncoplanar IMRT, single coplanar IMAT, double coplanar IMAT, single noncoplanar IMAT, and double noncoplanar IMAT. For each method, the dose to 95% of the PTV was held constant, and the doses to surrounding critical structures were minimized. The different plans were compared based on conformity, total linear accelerator dose monitor units, and dose to surrounding normal tissues, including the entire body, whole brain, temporal lobes, brainstem, and cochleae. Results: The doses to the target and critical structures for the various IMAT methods were not statistically different in comparison with the noncoplanar IMRT plan, with the following exceptions: the cochlear doses were higher and whole brain dose was lower for coplanar IMAT plans; the cochleae and temporal lobe doses were lower and conformity increased for noncoplanar IMAT plans. The advantage of the noncoplanar IMAT plan was enhanced by doubling the treatment arc. Conclusion: Noncoplanar IMAT results in superior treatment plans when compared to noncoplanar IMRT for the treatment of posterior fossa tumors. IMAT should be considered alongside IMRT when treatment of this site is indicated.

Beltran, Chris, E-mail: [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN (United States); Gray, Jonathan; Merchant, Thomas E. [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN (United States)



Posterior segment ocular manifestations of HIV/AIDS patients  

PubMed Central

Abstract Human immunodeficiency virus (HIV) has the ability to affect any organ in the body. In 70% of HIV -infected patients ocular manifestations were observed, these, in the vast majority reflect the systemic disease and may be the first signs of disseminated infections. Aim: The purpose of this paper is to determine the prevalence of posterior segment ocular manifestations in HIV / AIDS (Acquired Immunodeficiency Syndrome) patients. Method: The study is retrospective, conducted in the Cabinet of Ophthalmology of "Matei Bals" Infectious Diseases Hospital in Bucharest, during the period 1 August 2007 - 1 August 2013 . Each patient was examined thoroughly at the biomicroscope ocular slit by using 90D microscope lens and 20D indirect lens after the administration of topical mydriatics. Results: 348 patients with HIV/AIDS and ocular disorders were followed. There was a high number of children and young people with HIV who had eye disorders (194 patients aged between 14 and 25 years). 44.25% of patients had posterior segment ocular damage, 17.55% of them had the anterior segment affected. 22.90% of the 131 patients with compromised posterior segment microangiopathy have been diagnosed with HIV / AIDS. Conclusions: Doctors should be aware of the existence of ocular damage in HIV / AIDS and to emphasize the importance of regular ophthalmologic examination of patients with HIV / AIDS. Abbreviations: HIV- human immunodeficiency virus, AIDS- acquired immunodeficiency syndrome, CMV retinitis-cytomegalovirus retinitis PMID:25408764

Chiotan, C; Radu, L; Serban, R; Corn?cel, C; Cioboat?, M; Anghelie, A



Accurate capacitive metrology for atomic force microscopy  

E-print Network

This thesis presents accurate capacitive sensing metrology designed for a prototype atomic force microscope (AFM) originally developed in the MIT Precision Motion Control Lab. The capacitive measurements use a set of ...

Mazzeo, Aaron D. (Aaron David), 1979-



Electromechanical flowmeter accurately monitors fluid flow  

NASA Technical Reports Server (NTRS)

Electromechanical flowmeter remotely and accurately monitors the flow rate and total volume of a transparent liquid discharged from a dispensing system. A dual dispensing tube system provides a relative reference level which permits compensation for temperature variations.

Grant, D. J.



Importance Sampling Monte Carlo simulations for accurate estimation of SRAM yield  

E-print Network

Importance Sampling Monte Carlo simulations for accurate estimation of SRAM yield T.S. Doorn1 , E--Variability is an important aspect of SRAM cell design. Failure probabilities of Pfail10-10 have to be estimated through that a simple form of Importance Sampling is sufficient for simulating Pfail10-10 for the SRAM parameters Static

Eindhoven, Technische Universiteit


Thermochemistry and accurate quantum reaction rate calculations for H2\\/HD\\/D2 + CH3  

Microsoft Academic Search

Accurate quantum-mechanical results for thermodynamic data, cumulative reaction probabilities (for J = 0), thermal rate constants, and kinetic isotope effects for the three isotopic reactions H-2 + CH3 -> CH4 + H, HD + CH3 -> CH4 + D, and D-2 + CH3 -> CH3D + D are presented. The calculations are performed using flux correlation functions and the multiconfigurational

Gunnar Nyman; Rob van Harrevelt; Uwe Manthe



Accurate determination of distortion for smartphone cameras.  


Smartphone camera lenses have become prevalent. Photographs, and video, taken by such lenses have many useful applications which depend on accurately knowing the distortion properties of the lens. In this paper, we present an accurate method to determine smartphone camera lens distortion to an estimated average error of 0.09%. We present a linear regression method and account for keystone distortion and conjugate change. PMID:25322404

Lee, Sukmock; Kim, Byongoh; Lee, Jiyeon; Sasian, Jose



Imprecise probabilities in engineering analyses  

NASA Astrophysics Data System (ADS)

Probabilistic uncertainty and imprecision in structural parameters and in environmental conditions and loads are challenging phenomena in engineering analyses. They require appropriate mathematical modeling and quantification to obtain realistic results when predicting the behavior and reliability of engineering structures and systems. But the modeling and quantification is complicated by the characteristics of the available information, which involves, for example, sparse data, poor measurements and subjective information. This raises the question whether the available information is sufficient for probabilistic modeling or rather suggests a set-theoretical approach. The framework of imprecise probabilities provides a mathematical basis to deal with these problems which involve both probabilistic and non-probabilistic information. A common feature of the various concepts of imprecise probabilities is the consideration of an entire set of probabilistic models in one analysis. The theoretical differences between the concepts mainly concern the mathematical description of the set of probabilistic models and the connection to the probabilistic models involved. This paper provides an overview on developments which involve imprecise probabilities for the solution of engineering problems. Evidence theory, probability bounds analysis with p-boxes, and fuzzy probabilities are discussed with emphasis on their key features and on their relationships to one another. This paper was especially prepared for this special issue and reflects, in various ways, the thinking and presentation preferences of the authors, who are also the guest editors for this special issue.

Beer, Michael; Ferson, Scott; Kreinovich, Vladik



Running Head: Understandings of Probability Teachers' Understandings of Probability  

E-print Network

conducted an eight-day seminar with eight high school statistics teachers in the summer of 2001. The data we to understand in high school. Since its origin in the mid-seventeen century, probability theory has had it found applications in sociology, physics, biology and psychology; in the 20th century it was applied

Thompson, Patrick W.


Optimal Stopping under Probability Distortion  

E-print Network

We formulate an optimal stopping problem where the probability scale is distorted by a general nonlinear function. The problem is inherently time inconsistent due to the Choquet integration involved. We develop a new approach, based on a reformulation of the problem where one optimally chooses the probability distribution or quantile function of the stopped state. An optimal stopping time can then be recovered from the obtained distribution/quantile function via the Skorokhod embedding. This approach enables us to solve the problem in a fairly general manner with different shapes of the payoff and probability distortion functions. In particular, we show that the optimality of the exit time of an interval (corresponding to the "cut-loss-or-stop-gain" strategy widely adopted in stock trading) is endogenous for problems with convex distortion functions, including ones where distortion is absent. We also discuss economical interpretations of the results.

Xu, Zuo Quan



Cdx and Hox Genes Differentially Regulate Posterior Axial Growth in Mammalian Embryos  

Microsoft Academic Search

Hox and Cdx transcription factors regulate embryonic positional identities. Cdx mutant mice display posterior body truncations of the axial skeleton, neuraxis, and caudal urorectal structures. We show that trunk Hox genes stimulate axial extension, as they can largely rescue these Cdx mutant phenotypes. Conversely, posterior (paralog group 13) Hox genes can prematurely arrest posterior axial growth when precociously expressed. Our

Teddy Young; Jennifer Elizabeth Rowland; Cesca van de Ven; Monika Bialecka; Ana Novoa; Marta Carapuco; Johan van Nes; Wim de Graaff; Isabelle Duluc; Jean-Noël Freund; Felix Beck; Moises Mallo; Jacqueline Deschamps



Posterior corneal aberrations and their compensation effects on anterior corneal aberrations in keratoconic eyes  

E-print Network

compensatory effects between anterior and posterior corneal surfaces. METHODS The corneal topography of a total the corneal aberrations. The central 6-mm diameter of both anterior and posterior corneal topographiesPosterior corneal aberrations and their compensation effects on anterior corneal aberrations

Yoon, Geunyoung


Estimation of Posterior Fossa Volume in Pediatric Patients with Chiari Malformations by the Cavalieri Principle  

Microsoft Academic Search

Chiari malformations (CMs) involve pathological hindbrain abnormalities reported to be correlated with a hypoplastic posterior fossa. This study calculates posterior fossa volume estimate using MRI. A retrospective review was conducted on patients who were admitted to our hospital. Clinical and radiological assessments were performed. Posterior fossa volumes (PFV) and intracranial volumes (ICV) were measured from head MRI scans using the

Chunquan Cai; Qingjiang Zhang; Changhong Shen; Weidong Yang; Ouyan Shi



Quantification of Posterior Capsular Opacification in Digital Images after Cataract Surgery  

Microsoft Academic Search

PURPOSE. To describe a software program developed to provide an objective assessment of the amount of posterior capsular opacification (PCO) in high-resolution digital images of the posterior capsule after cataract surgery. METHODS. Images are analyzed by a set protocol of defining the area of the posterior capsule, removing the Purkinje light reflexes by intensity segmentation, contrast enhancement, filtering to enhance

Sarah A. Barman; Emma J. Hollick; James F. Boyce; David J. Spalton; Bunyarit Uyyanonvara; Giorgia Sanguinetti; William Meacock



Comparison of Dynesys posterior stabilization and posterior lumbar interbody fusion for spinal stenosis L4L5.  


The aim of this prospective randomized study was to compare the radiological and clinical outcome after treatment of lumbar spinal stenosis L4L5 with or without spondylolisthesis, with either posterior lumbar interbody fusion (PLIF) (26 patients) or Dynesys posterior stabilization (27 patients). Demographic characteristics were comparable in both groups. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (p < 0.001), and significantly less (p < 0.05) hypermobility at the adjacent segments. Oswestry Disability Index (ODI) and VAS for back and leg pain improved significantly (p < 0.05) with both methods, but there was no significant difference between groups. Operation time, blood loss, and length of hospital stay were all significantly (p < 0.001) less in the Dynesys group. The latter benefits may be of particular importance for elderly patients, or those with significant comorbidities. Complications were comparable in both groups. Dynesys posterior stabilization was effective for treating spinal stenosis L4L5 with or without spondylolisthesis. PMID:22696995

Yu, Shang-Won; Yang, Shih-Chieh; Ma, Ching-Hou; Wu, Chin-Hsien; Yen, Cheng-Yo; Tu, Yuan-Kun



Interference of probabilities in dynamics  

NASA Astrophysics Data System (ADS)

A new class of dynamical systems with a preset type of interference of probabilities is introduced. It is obtained from the extension of the Madelung equation by replacing the quantum potential with a specially selected feedback from the Liouville equation. It has been proved that these systems are different from both Newtonian and quantum systems, but they can be useful for modeling spontaneous collective novelty phenomena when emerging outputs are qualitatively different from the weighted sum of individual inputs. Formation of language and fast decision-making process as potential applications of the probability interference is discussed.

Zak, Michail



The Posterior Distribution of the Likelihood Ratio as a Measure of Evidence  

NASA Astrophysics Data System (ADS)

This paper deals with simple versus composite hypothesis testing under Bayesian and frequentist settings. The Posterior distribution of the Likelihood Ratio (PLR) concept is proposed in [1] for significance testing. The PLR is shown to be equal to 1 minus the p-value in a simple case. The PLR is used in [2] in order to calibrate p-values, Fractional Bayes Factors (FBF) and others. Dempster's equivalence result is slightly extended by adding a nuisance parameter in the test. On the other hand, in [3] the p-values and the posterior probability of the null hypothesis Pr(H0|x) (seen as a Bayesian measure of evidence against the null hypothesis) are shown to be irreconcilable. Actually, as emphasized in [4], Pr(H0|x) is a measure of accuracy of a test, not a measure of evidence in a formal sense because it does not involve the likelihood ratio. The PLR may give such a measure of evidence and be related to a natural p-value. In this presentation, in a classical invariance framework the PLR with inner threshold 1 will be shown to be equal to 1 minus a p-value where the test statistics is the likelihood, weighted by a term that accounts for some volume distorsion effect. Other analytical properties of the PLR will be proved in more general settings. The minimum of its support is equal to the Generalized Likelihood Ratio if H0 is nested in H1 and its moments are directly related to the (F)BF for a proper prior. Its relation to credible domains is also studied. Practical issues will also be considered. The PLR can be implemented using a simple Monte Carlo Markov Chain and will be applied to extrasolar planet detection using direct imaging.

Smith, I.; Ferrari, A.



Estimating Second Order Probability Beliefs from Subjective Survival Data  

PubMed Central

Based on subjective survival probability questions in the Health and Retirement Study (HRS), we use an econometric model to estimate the determinants of individual-level uncertainty about personal longevity. This model is built around the modal response hypothesis (MRH), a mathematical expression of the idea that survey responses of 0%, 50%, or 100% to probability questions indicate a high level of uncertainty about the relevant probability. We show that subjective survival expectations in 2002 line up very well with realized mortality of the HRS respondents between 2002 and 2010. We show that the MRH model performs better than typically used models in the literature of subjective probabilities. Our model gives more accurate estimates of low probability events and it is able to predict the unusually high fraction of focal 0%, 50%, and 100% answers observed in many data sets on subjective probabilities. We show that subjects place too much weight on parents’ age at death when forming expectations about their own longevity, whereas other covariates such as demographics, cognition, personality, subjective health, and health behavior are under weighted. We also find that less educated people, smokers, and women have less certain beliefs, and recent health shocks increase uncertainty about survival, too. PMID:24403866

Hudomiet, Peter; Willis, Robert J.



[Updates of ossification of posterior longitudinal ligament. Clinical results and complication of surgery for thoracic myelopathy due to ossification of posterior longitudinal ligament].  


We performed 3 types of surgical procedures for thoracic myelopathy due to OPLL : posterior decompression, OPLL-extirpation, and posterior decompression with instrumented fusion (PDF) . A considerable degree of neurological recovery was obtained in all patients who underwent PDF, despite the anterior impingement of the spinal cord by OPLL remaining. In addition, the rate of post-operative complications was extremely low with PDF, when compared with posterior decompression and OPLL-extirpation groups. We recommend that one stage posterior decompression with instrumented fusion be selected for cases in whom the spinal cord is severely damaged pre-operatively. PMID:19794260

Yamazaki, Masashi



Calculating state-to-state transition probabilities within TDDFT  

E-print Network

The determination of the elements of the S-matrix within the framework of time-dependent density-functional theory (TDDFT) has remained a widely open question. We explore two different methods to calculate state-to-state transition probabilities. The first method closely follows the extraction of the S-matrix from the time-dependent Hartree-Fock approximation. This method suffers from cross-channel correlations resulting in oscillating transition probabilities in the asymptotic channels. An alternative method is proposed which corresponds to an implicit functional in the time-dependent density. It gives rise to stable and accurate transition probabilities. An exactly solvable two-electron system serves as benchmark for a quantitative test.

Nina Rohringer; Simone Peter; Joachim Burgdörfer



Learning Resources: Statistics: Non-Probability Sampling  

NSDL National Science Digital Library

This is website, presented by Statistics Canada, examines the concept of non-probability sampling. It discusses types of non-probability sampling, differences between probability and non-probability sampling, and provides examples of non-probability sampling. Links to other topics related to sampling methods, bias, and exercise activities are also provided.

Legge, Joe A.



Combining binary classifiers with imprecise probabilities.  

E-print Network

Combining binary classifiers with imprecise probabilities. Sébastien Destercke1 and Benjamin Quost2 whose outputs are imprecise probabilities (or are transformed into some imprecise probabilities, e probabilities estimating whether an instance belong to a given class subset, these conditional probabilities

Paris-Sud XI, Université de


Probability and Statistics K-6  

NSDL National Science Digital Library

This webpage based on the Western Canadian Protocol for grades K-6 details activities for the seventeen objectives in the Probability and Statistics strand. Each objective links to a page that includes a problem, a manipulative activity, and a game. Some of the activities require special cards, spinners, cutouts, etc. which are provided at the bottom of the webpage in PDF format.

Loewen, Craig




E-print Network

MACHINE MONITORING USING PROBABILITY THRESHOLDS AND SYSTEM OPERATING CHARACTERISTICS Stephen M a discrete-part production machine, with the objective of effectively determining when to shut the machine analysis: a) There is an underlying time interval that characterizes the operation of the machine, most

Pollock, Stephen


Probability (Math/Stat 511)  

E-print Network

every 10 meters of computer tape. If these are distributed as a Poisson process, then a.) give to a Poisson process on the average of two every five minutes. Let X denote the waiting time until the firstProbability (Math/Stat 511) Test 3 ­ April 4, 2001 Directions: Answer all questions in the space

Sharpley, Robert


Conditional Independence in Applied Probability.  

ERIC Educational Resources Information Center

This material assumes the user has the background provided by a good undergraduate course in applied probability. It is felt that introductory courses in calculus, linear algebra, and perhaps some differential equations should provide the requisite experience and proficiency with mathematical concepts, notation, and argument. The document is…

Pfeiffer, Paul E.


Let the Probability Games Begin  

NSDL National Science Digital Library

This collection of eight learning activities can be utilized with 1st or 2nd grade students to promote the practice of data collection through games and to introduce the concepts of probability through discussion about predictions and likelihood. Each of the eight activities has a list of materials and a worksheet attached that can be utilized to explain and complete each task.

Plans, Utah L.



Total Probability and Bayes' Theorem  

E-print Network

other than those already known. For example, if production runs of ball bearings involve say, four machines, we might well know the probability that any given machine produces faulty ball bearings. If we that a faulty ball bearing came from a particular machine. Even though we do not address the area of statistics

Vickers, James


Probability Distributions on Positive Semigroups  

Microsoft Academic Search

The algebraic structure ((0;1);+;•), together with the usual topol- ogy and Lebesgue measure, is the standard representation of time for a variety of probabilistic models. These include reliability theory and the aging of lifetime distributions, renewal processes,, and Markov processes, to name just a few. The purpose of this monograph is to study probability models in which the standard representation

Kyle Siegrist


Intersymbol interference and error probability  

Microsoft Academic Search

Using a criterion of minimum average error probability we derive a method for specifying an optimum linear, time invariant receiving filter for a digital data transmission system. The transmitted data are binary and coded into pulses of shapepm s(t). The linear transmission medium introduces intersymbol interference and additive Gaussian noise. Because the intersymbol interference is not Gaussian and can be

M. Aaron; D. Tufts



Compensating for Word Posterior Estimation Bias in Confusion Networks  

Microsoft Academic Search

This paper looks at the problem of confidence estimation at the word network level, where multiple hypotheses from a recognizer are represented in a confusion network. Given features of the network, an SVM is used to estimate the probability that the correct word is missing from a candidate slot and then other word probabilities are normalized accordingly. The result is

Dustin Hillard; Mari Ostendorf



Accurate weak lensing of standard candles. I. Flexible cosmological fits  

E-print Network

With the availability of thousands of type Ia supernovae in the near future the magnitude scatter induced by lensing will become a major issue as it affects parameter estimation. Current N-body simulations are too time consuming to be integrated in the likelihood analyses used for estimating the cosmological parameters. In this paper we show that in the weak lensing regime a statistical numerical approximation produces accurate results orders of magnitude faster. We write down simple fits to the second, third and fourth central moments of the lensing magnification probability distribution as a function of redshift, of the power spectrum normalization and of the present-day matter density. We also improve upon existing models of lensing variance and show that a shifted lognormal distribution fits well the numerical one. These fits can be easily employed in cosmological likelihood analyses. Moreover, our theoretical predictions make it possible to invert the problem and begin using supernovae lensing to constrain the cosmological parameters.

Valerio Marra; Miguel Quartin; Luca Amendola



Posterior fossa cystic lesions--magnetic resonance imaging manifestations.  


Cystic lesions of the posterior fossa remain a controversial subject as to clinical classification and diagnosis, especially for those in combination with other intracranial abnormalities. During the period of November 1985 to June 1991, 16 patients with cystic lesions of the posterior fossa were retrospectively reviewed on neuroradiological evaluation with MR images. The patients were 9 males and 7 females aged from 5 days to 15 years old (medium 1 year old). They were classified into three groups as Dandy-Walker cyst (group A, 5 patients), mega cisterna magna (group B, 4) and retrocerebellar pouch or cyst (group C, 7). Nine patients had associated intracranial anomalies, holoprosencephaly in 3 (group A, 3), dysgenesis of the corpus callosum in 4 (group A, 2; group C, 2), and occipital meningoceles in 2 (group C, 2). Hydrocephalus or ventricular enlargement was found in 10 patients (group A, 5; group B, 2; group C, 3). Surgical treatment (cyst-peritoneal shunt or cystectomy) was performed for 10 patients with clinical symptoms due to cyst. Postoperatively, clinical symptoms due to increased intracranial pressure or hydrocephalus improved in 7 patients. For long-term results, the cyst was reduced in 1 of 5 patients of group A and 2 of 5 of group C. Most of our patients have a poor prognosis because of the associated intracranial anomalies or atrophy of the cerebellum. Multiplanar MR images may provide sufficient evidence for the diagnosis of posterior fossa cysts, especially in the case of rotation or upward displacement of the cerebellar vermis. However, the cyst membrane, and the communication of fluid between the cyst and the cistern, cannot be demonstrated on MR images. Further investigation on these subjects and indications for surgical intervention is highly necessary. PMID:8747420

Tan, E C; Takagi, T; Karasawa, K



Medioventral part of the posterior thalamus in the mouse.  


The posterior thalamus (Po) consists of heterogeneous groups of cells, which have not been clearly defined. In the present study, we focused on a part of the Po in the mouse brain, which is located caudally to the ventral posterior nucleus and rostromedially to the medial geniculate nucleus and shows distinct calretinin immunoreactivity. While we found the region had a considerable unity on the cytoarchitectural and histochemical grounds, it did not correspond to any particular nucleus but partially involved three structures in a widely used brain atlas (Franklin and Paxinos, 2008). Therefore, we tentatively designated the region as the medioventral part of the posterior thalamus (PoMV) and examined its anatomical features with immunohistochemistry and retrograde tract-tracing. The PoMV was appreciated as a reticular structure with prominent calretinin immunoreactivity, especially in horizontal sections, and displayed apparent differences in the cytoarchitecture from its surrounding regions. The PoMV had two divisions: the dorsal division (PoMVd), which contained parvalbuminimmunoreactive fibers, and the ventral division (PoMVv), which lacked these fibers. The tract-tracing studies showed that the somata retrogradely labeled from the injections in the insular cortex and some of the extended amygdalar regions were fairly concentrated within the PoMV, especially in the PoMVd. On the other hand, the labeling from the medial hypothalamus injections was found predominantly within the PoMVv. These findings indicate that the PoMV can be regarded as a distinct structure within the Po, and it may play a role in the emotional aspect of somatosensory processing. PMID:21824514

Motomura, Keisuke; Kosaka, Toshio



Three-dimensional load displacement properties of posterior lumbar fixation.  


Pedicular fixation devices for the posterior treatment of segmental spinal instability are thought to offer enhanced stabilization compared with sublaminar wire systems, while avoiding the immobilization of multiple normal motion segments. We compared the performance of three dissimilar stabilization systems: the Hartshill rectangle, the Acromed/Steffee interpedicular screw and plate, and the Synthes/Dick fixateur interne. Human cadaveric lumbosacral specimens were first tested intact, then after a laminectomy and a facetectomy at the L3/L4 level, and finally after the fixation devices were sequentially attached. Constructs spanning two to four vertebral levels were compared for stabilization of the resected lumbar spine segments. When tested in compression, the Acromed/Steffee system with pedicular screws at L2-L5 allowed significantly less intersegmental distraction than the Synthes/Dick construct with screws at L2 and L5 only, and less than the intact and the destabilized uninstrumented spine. When sagittally rotated, the Acromed/Steffee construct with screws at L2-L5, or at L2 and L5, allowed significantly less distraction than the intact or destabilized segments, and the construct with screws at L2 through L5 allowed less distraction than the Synthes/Dick constructs with screws at L3/L4 or L2/L5. With the exception of the Acromed/Steffee system with screws at four levels, there were no significant differences in distraction allowed between the Synthes/Dick and Acromed/Steffee constructs, or between the multisegment and single segment constructs. There were no significant differences in stiffness across levels L3/L4 with the various implants. Results indicate that the use of posterior spine constructs significantly augment the stability of posterior segmental defects. Pedicular fixation immediately cephalad and caudad to the defect provided stable fixation in this application. PMID:1762002

Shea, M; Edwards, W T; Clothiaux, P L; Crowell, R R; Nachemson, A L; White, A A; Hayes, W C



Experimental lens capsular bag model for posterior capsule opacification.  


An in vitro culture model enabling posterior capsule opacification (PCO) to be investigated was developed and established by using low-melting-point (LMP)-agarose gel to support the capsular bag. After removal of the cornea from rodent and porcine eyeballs, the lens zonules were dissected. Whole lens explants were embedded into 2 % (37 °C) LMP-agarose gel solution. As performed routinely in cataract surgery, capsulotomy and lens fiber removal were carried out in the solidified LMP-agarose gel as sham cataract surgery. The LMP-agarose-gel-supported capsular bag/lens epithelial cell (CB-LEC) complexes were maintained in Dulbecco's modified Eagle medium supplemented with 10 % fetal bovine serum in an anterior face-down position. The proliferation and migration of LECs into the posterior capsule were observed every 12 h by phase-contrast microscopy. Epithelial cells were observed at the central portion of the CB-LEC complexes after 56.57?±?16.56 h (n?=?7) and 106?±?14.03 h (n?=?6) of culture, for rodent and porcine lenses, respectively. The solidified gel allowed clear microscopic observations and whole-mount immunostaining evaluations of the whole area of the capsular bag. Histological examinations revealed the proliferation, migration, and transdifferentiation of LECs related to posterior capsule opacification. This new in vitro culture model provides experimental benefits by maintaining the natural contour of the capsule without implants inside or outside of the capsule. In addition, this model system allows pharmacological and histological evaluations of the cultured CB-LEC complexes without additional manipulations. PMID:24793776

Jun, Jong Hwa; Sohn, Wern-Joo; Lee, Youngkyun; Chang, Sung Dong; Kim, Jae-Young



Finding thalamic BOLD correlates to posterior alpha EEG.  


Oscillatory electrical brain activity in the alpha (8-13 Hz) band is a prominent feature of human electroencephalography (EEG) during alert wakefulness, and is commonly thought to arise primarily from the occipital and parietal parts of the cortex. While the thalamus is considered to play a supportive role in the generation and modulation of cortical alpha rhythms, its precise function remains controversial and incompletely understood. To address this, we evaluated the correlation between the blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals in the thalamus and the spontaneous modulation of posterior alpha rhythms based on EEG-fMRI data acquired concurrently during an eyes-closed task-free condition. We observed both negative and positive correlations in the thalamus. The negative correlations were mostly seen within the visual thalamus, with a preference for the pulvinar over lateral geniculate nuclei. The positive correlations were found at the anterior and medial dorsal nuclei. Through functional connectivity analysis of the fMRI data, the pulvinar was found to be functionally associated with the same widespread cortical visual areas where the fMRI signals were negatively correlated with the posterior alpha modulation. In contrast, the dorsal nuclei were part of a distinct functional network that included brain stem, cingulate cortex and cerebellum. These observations are consistent with previous animal electrophysiology studies and the notion that the visual thalamus, and the pulvinar in particular, is intimately involved in the generation and spontaneous modulation of posterior alpha rhythms, facilitated by its reciprocal and widespread interaction with the cortical visual areas. We further postulate that the anterior and medial dorsal nuclei, being part of the ascending neuromodulatory system, may indirectly modulate cortical alpha rhythms by affecting vigilance and arousal levels. PMID:22986355

Liu, Zhongming; de Zwart, Jacco A; Yao, Bing; van Gelderen, Peter; Kuo, Li-Wei; Duyn, Jeff H



Posterior trochanteric osteotomy in acetabular fractures for 32 cases.  


The aim of this study is to explore the method and clinical outcome of posterior trochanteric osteotomy in acetabular fractures. From January 2000 to January 2008, 32 cases of acetabular fractures involving the dome of acetabulum underwent posterior trochanteric osteotomy for a better exposure and internal fixation with acetabular tridimensional memory fixation system. 28 cases (16 men and 12 women, mean age 39.9 years, range 16-73 years) were followed up with an average of 48.9 months (range of 19-95 months) and four were lost during follow up. Of 28 cases, 19 were fresh fractures and 9 were old fractures. The reduction was evaluated with Matta criteria. Clinical evaluation was based on modified Merle d'Aubigne and Postel scoring. Motor strength of the abductors was evaluated according to the Medical Research Council grading system. Ectopic ossification was classified according to Brooker criteria. Anatomical reduction was achieved in 17 cases and satisfied reduction in 10 patients. Poor reduction happened in an old fracture. All acetabular fractures got a direct bone union and no displacement and deep infection occurred. All osteotomies healed within 3.5 months without any nonunion, proximal migration of the greater trochanter, loosing or broken of instrumentation, and deep infection. Two superficial infections were healed with a regular dressing. Two patients underwent removal of implants from greater trochanter because of irritation. The strength of the abductors was of Grade 3/5 in two patients, Grade 4/5 in five patients, and normal in the rest. Clinical scoring was excellent to good in 84 %. Ectopic ossification occurred in five patients, grade 1 in two patients, grade 2 in two, and grade 3 in one. But function of hip joint was not seriously affected. Posterior trochanteric osteotomy can provide an adequate exposure of the dome of acetabulum without the associated complications like nonunion, proximal replacement, and weak of the abductors which often occur with standard oblique osteotomy. PMID:25113643

Niu, Yunfei; An, Xiaofei; Xu, Shuogui; Wu, Dajiang; Zhang, Chuncai; Li, Ming



47 CFR 1.1623 - Probability calculation.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Probability calculation. 1.1623 Section... General Procedures § 1.1623 Probability calculation. (a) All calculations...less than three significant digits. Probabilities will be truncated to the number...



47 CFR 1.1623 - Probability calculation.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Probability calculation. 1.1623 Section... General Procedures § 1.1623 Probability calculation. (a) All calculations...less than three significant digits. Probabilities will be truncated to the number...



47 CFR 1.1623 - Probability calculation.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Probability calculation. 1.1623 Section... General Procedures § 1.1623 Probability calculation. (a) All calculations...less than three significant digits. Probabilities will be truncated to the number...



Modeling Prostate Cancer Detection Probability, with Applications  

E-print Network

Modeling Prostate Cancer Detection Probability, with Applications Robert Serfling1 University Prostate Cancer Detection Probability, with Applicati #12;Outline Background and Overview Building Concluding Comments Acknowledgements Robert Serfling Modeling Prostate Cancer Detection Probability

Serfling, Robert


Using Playing Cards to Differentiate Probability Interpretations  

ERIC Educational Resources Information Center

The aprioristic (classical, naïve and symmetric) and frequentist interpretations of probability are commonly known. Bayesian or subjective interpretation of probability is receiving increasing attention. This paper describes an activity to help students differentiate between the three types of probability interpretations.

López Puga, Jorge



On the probability distributions of ellipticity  

NASA Astrophysics Data System (ADS)

In this paper we derive an exact full expression for the 2D probability distribution of the ellipticity of an object measured from data, only assuming Gaussian noise in pixel values. This is a generalization of the probability distribution for the ratio of single random variables, that is well known, to the multivariate case. This expression is derived within the context of the measurement of weak gravitational lensing from noisy galaxy images. We find that the third flattening, or ?-ellipticity, has a biased maximum likelihood but an unbiased mean; and that the third eccentricity, or normalized polarization ?, has both a biased maximum likelihood and a biased mean. The very fact that the bias in the ellipticity is itself a function of the ellipticity requires an accurate knowledge of the intrinsic ellipticity distribution of the galaxies in order to properly calibrate shear measurements. We use this expression to explore strategies for calibration of biases caused by measurement processes in weak gravitational lensing. We find that upcoming weak-lensing surveys like KiDS or DES require calibration fields of the order of several square degrees and 1.2 mag deeper than the wide survey in order to correct for the noise bias. Future surveys like Euclid will require calibration fields of order 40 square degree and several magnitude deeper than the wide survey. We also investigate the use of the Stokes parameters to estimate the shear as an alternative to the ellipticity. We find that they can provide unbiased shear estimates at the cost of a very large variance in the measurement. The PYTHON code used to compute the distributions presented in the paper and to perform the numerical calculations are available on request.

Viola, M.; Kitching, T. D.; Joachimi, B.



Late relapse of testicular seminoma in the posterior mediastinum.  


Patients with testicular seminoma are usually cured if they survive disease-free for 5 years after therapy. Late relapse can also occur but is rare. In particular, relapse of testicular seminoma in the form of a large mediastinal mass is extremely rare. We present here a 37-year-old man with a late relapse of a large testicular seminoma in the posterior mediastinum, encasing the descending thoracic aorta, and compressing the left atrium and left main bronchus on computed tomography (CT) and positron emission tomography (PET). PMID:23466004

Shin, Dong Jae; Kim, Jeung Sook; Kim, Do Yeun; Yeo, Jeong Seok



Arteries in the posterior cervical triangle in man.  


Due to frequent changes in the anatomical nomenclature of the arteries in the posterior cervical triangle (lateral cervical region), anatomical and surgical papers relating to these topics are sometimes difficult to understand and are hard to compare. These changes, coupled with improper knowledge of the gross anatomy and nomenclature of the arteries in the posterior cervical triangle, have presented difficulties in musculocutaneous flap planning, especially in plastic and reconstructive surgery. As an illustration of this concern, the term, transverse cervical artery (A. transversa colli [cervicis]), and its associated branches, have been used frequently over the past several decades with different meanings. In an effort to address this nomenclature challenge and to offer a rational basis for arguing specific name changes, a total of 498 neck-halves were investigated in Graz, Innsbruck, and Munich. Lateral neck dissections were carried out to expose the subclavian artery and those branches destined for the posterior cervical triangle, specifically, the superficial cervical artery, the dorsal scapular artery, and the suprascapular artery. The course of these arteries and details of their origins and branching patterns were documented. Several arose either as direct branches or from trunks. The convention used in labeling trunks was similar to that described for other trunk formations in the body (e.g., linguo-facial trunk). Four trunks were observed and named according to the branches that arose from each. A cervico-dorsal trunk gave origin to the superficial cervical and dorsal scapular arteries, and was found in 30% of cases. A cervico-scapular trunk gave rise to the superficial cervical and suprascapular arteries in 22% of cases, and a dorso-scapular trunk provided origins for the dorsal scapular and suprascapular arteries in 4% of cases. A cervico-dorso-scapular trunk gave origin to the superficial cervical artery, the dorsal scapular artery, and the suprascapular artery, and was found in 24% of cases. Each of these trunks, in turn, arose from either the subclavian artery or from the thyrocervical trunk. This labeling convention necessitated omitting the term, transverse cervical artery, because this term has become inherently imprecise and variously used over the years. This study describes a simple, uniform, and rational basis for standardizing the nomenclature of the arteries in the posterior cervical triangle. PMID:16187318

Weiglein, Andreas H; Moriggl, B; Schalk, C; Künzel, K H; Müller, U



Giant liposarcoma of the posterior mediastinum and retroperitoneum  

PubMed Central

A 39-year-old Japanese man has been complaining of chest pain for 3 months and a CT revealed a huge tumour in the posterior mediastinum and retroperitoneum. The mediastinal tumour was continuous with the retroperitoneal one through the oesophageal hiatus and the lower oesophagus was completely surrounded by the tumour. MRI suggested lipogenic tumour. Resection of the tumour with oesophagectomy was performed through bilateral thoracotomy and laparotomy. Pathological examination revealed well-differentiated liposarcoma which was completely resected. The patient has been alive without recurrence for 14 months after surgery. PMID:22688481

Taki, Katsunobu; Watanabe, Masayuki; Iwagami, Shiro; Nagai, Yohei; Iwatsuki, Masaaki; Ishimoto, Takatsugu; Baba, Yoshifumi; Miyamoto, Yuji; Baba, Hideo



LETTER Licorice consumption-associated thunderclap headache: posterior reversible encephalopathy  

E-print Network

van Beers and colleagues described a 49-year-old woman admitted to hospital for thunderclap headache, blurred vision and hypertension. Based on clinical manifestations, diagnostic work-up and follow-up, the authors diagnosed the case as posterior reversible encephalopathy syndrome (PRES) [1]. We agree that PRES should be considered in this case, while differential diagnosis such as subarachnoid hemorrhage (SAH) requires further investigation and exclusion. PRES represents a clinicoradiological disease entity arising from failure of cerebrovascular autoregulation and ensuing disruption of the blood–brain barrier upon acuteonset hypertension [2]. The underlying patho genesis of PRES is vasogenic edema, which requires apparent diffusion coefficient mapping by magnetic reso nance

Hongliang Zhang; Xiao-feng Wang; Jiang Wu


Neurenteric cysts of the posterior fossa: recognition, management, and embryogenesis.  


Neurenteric cysts are endothelium-lined structures most commonly encountered in the lower cervical or upper thoracic spinal cord. The occurrence of neurenteric cysts within the cranial vault is unusual. We present three patients with neurenteric cysts located within the posterior fossa: one near the jugular foramen deforming the 4th ventricle, a second in the cerebellopontine angle, and a third in the prepontine cistern. Several different theories have been advanced to explain the embryogenesis of neurenteric cysts. We review these theories and conclude that cranial neurenteric cysts may arise from a disturbance of early gastrulation, shortly after the onset of primitive streak regression. PMID:1758603

Harris, C P; Dias, M S; Brockmeyer, D L; Townsend, J J; Willis, B K; Apfelbaum, R I



Application of sonography for evaluation of posterior circulation disorders.  


Posterior circulation disorders (PCD) include a) vertebrobasilar insufficiency (VBI), which has a wide clinical manifestation such as vestibulocerebellar syndrome, cephalalgia, cochlear syndrome, vegetovascular dystonia, visual disturbances, "syndrome of vertebral artery compression" etc, b) vertebrobasilar TIA and c) stroke. All of them are caused by blood flow disturbances in vertebral (VA), basilar (BAS) and posterior cerebral arteries (PCA). Aim - evaluation of role of extracranial duplex-sonography (EDS), transcranial color-coded duplex-sonography (TCCD) and rotational functional tests (RFT) in PCD. 88 patients (age range 18-62y) with PCD and 20 healthy controls with relevant age range were examined using EDS, TCCD and RFT with measurement of vertebral arteries (VA) diameter, mean flow velocities (MFV) and pulsatility index (PI) in VA, basilar artery (BAS) and posterior cerebral arteries (PCA). For statistical analysis SPSS software (Version 11.5) was used. In 48 (54,5%) patients revealed unilateral narrowing (less than 2.5 mm in diameter) and deformation of vertebral artery associated with osteochondrosis or primary hypoplasia. In 11 (12,5%) patients revealed bilateral narrowing (less than 2.8 mm in diameter) and deformation of vertebral arteries. Ultrasound investigation showed a decrease of MFV (23 ± 1.4 cm/sec) in the intracranial length of vertebral artery and an increase of PI (3,2 ±0,3 p=0,002) in the extracranial segments (V1- V3). In 52 cases (59%) revealed decrease of MFV in BAS by 32.6 ± 4.7% and in 41 cases (46.5%) decrease of MFV in both PCA by 24.8 ± 5.2% (P<0.002). In 21 cases (23.8%) revealed concurrent development of vertebrogenic reflex vasoconstriction. In 18 patients (20.4%) exposed only deformation of vertebral arteries with local increase of MFV and normal values in intracranial segments. Rotational tests were positive in 42 (47.7%) patients and manifested high correlation with clinical data. EDS and TCCD are important tools for estimation of high hemodynamic risk in patients with PCD. Rotation induced vertebrobasilar ischemia with temporary impairment of cerebral blood flow to the brainstem, thalamus, and occipital lobes predicts possible posterior circulation TIA or stroke and helps with proper selection of further treatment strategy. PMID:24743118

Alpaidze, M; Janelidze, M



Prodromal posterior cortical atrophy: clinical, neuropsychological, and radiological correlation.  


We present longitudinal clinical, cognitive, and neuroimaging data from a 63-year-old woman who enrolled in research as a normal control and evolved posterior cortical atrophy (PCA) over 5 year follow-up. At baseline she reported only subtle difficulty driving and performed normally on cognitive tests, but already demonstrated atrophy in left visual association cortex. With follow-up she developed insidiously progressive visuospatial and visuoperceptual deficits, correlating with progressive atrophy in bilateral visual areas. Amyloid PET was positive. This case tracks the evolution of PCA from the prodromal stage, and illustrates challenges to early diagnosis as well as the utility of imaging biomarkers. PMID:24308559

Chan, Lung Tat Andrew; Lynch, Whitney; De May, Mary; Horton, Jonathan C; Miller, Bruce L; Rabinovici, Gil D



Posterior reversible encephalopathy syndrome in a patient of organophosphate poisoning.  


A 32-year-old male presented with a history of consuming some organophosphorous compound with suicidal intention. He was treated with atropine, pralidoxime, ventilator support. During stay patient had persistent irritability, tachycardiaand hypertension despite sedation and labetalol infusion. He developed headache, visual blurring hemiparesis and focal seizures. Magnetic resonance imaging of the brain revealed multifocal hyperintensities mainly in subcortical areas of parietal and occipital regions in T2-weighted images, with increased values of Apparent Diffusion Coefficient, suggesting posterior reversible encephalopathy syndrome (PRES). The possibilities of PRES caused by organophosphorous poisoning either due to hypertension caused by autonomic deregulation or direct neurological toxicity has been discussed. PMID:24872658

Phatake, Rajesh; Desai, Sameer; Lodaya, Manikanth; Deshpande, Shrinivas; Tankasali, Nagaraj



Accurate and efficient reconstruction of deep phylogenies from structured RNAs  

PubMed Central

Ribosomal RNA (rRNA) genes are probably the most frequently used data source in phylogenetic reconstruction. Individual columns of rRNA alignments are not independent as a consequence of their highly conserved secondary structures. Unless explicitly taken into account, these correlation can distort the phylogenetic signal and/or lead to gross overestimates of tree stability. Maximum likelihood and Bayesian approaches are of course amenable to using RNA-specific substitution models that treat conserved base pairs appropriately, but require accurate secondary structure models as input. So far, however, no accurate and easy-to-use tool has been available for computing structure-aware alignments and consensus structures that can deal with the large rRNAs. The RNAsalsa approach is designed to fill this gap. Capitalizing on the improved accuracy of pairwise consensus structures and informed by a priori knowledge of group-specific structural constraints, the tool provides both alignments and consensus structures that are of sufficient accuracy for routine phylogenetic analysis based on RNA-specific substitution models. The power of the approach is demonstrated using two rRNA data sets: a mitochondrial rRNA set of 26 Mammalia, and a collection of 28S nuclear rRNAs representative of the five major echinoderm groups. PMID:19723687

Stocsits, Roman R.; Letsch, Harald; Hertel, Jana; Misof, Bernhard; Stadler, Peter F.



An accurate distance to 2M1207Ab  

E-print Network

In April 2004 the first image was obtained of a planetary mass companion (now known as 2M1207 b) in orbit around a self-luminous object different from our own Sun (the young brown dwarf 2MASSW J1207334-393254, hereafter 2M1207 A). 2M1207 b probably formed via fragmentation and gravitational collapse, offering proof that such a mechanism can form bodies in the planetary mass regime. However, the predicted mass, luminosity, and radius of 2M1207 b depend on its age, distance, and other observables such as effective temperature. To refine our knowledge of the physical properties of 2M1207 b and its nature, we obtained an accurate determination of the distance to the 2M1207 A and b system by measurements of its trigonometric parallax at the milliarcsec level. With the ESO NTT/SUSI2 telescope, in 2006 we began a campaign of photometric and astrometric observations to measure the trigonometric parallax of 2M1207 A. An accurate distance ($52.4\\pm 1.1$ pc) to 2M1207A was measured. From distance and proper motions we d...

Ducourant, C; Chauvin, G; Daigne, G; Campion, J F Le; Song, Inseok; Zuckerman, B



Understanding Y haplotype matching probability.  


The Y haplotype population-genetic terrain is better explored from a fresh perspective rather than by analogy with the more familiar autosomal ideas. For haplotype matching probabilities, versus for autosomal matching probabilities, explicit attention to modelling - such as how evolution got us where we are - is much more important while consideration of population frequency is much less so. This paper explores, extends, and explains some of the concepts of "Fundamental problem of forensic mathematics - the evidential strength of a rare haplotype match". That earlier paper presented and validated a "kappa method" formula for the evidential strength when a suspect matches a previously unseen haplotype (such as a Y-haplotype) at the crime scene. Mathematical implications of the kappa method are intuitive and reasonable. Suspicions to the contrary raised in rest on elementary errors. Critical to deriving the kappa method or any sensible evidential calculation is understanding that thinking about haplotype population frequency is a red herring; the pivotal question is one of matching probability. But confusion between the two is unfortunately institutionalized in much of the forensic world. Examples make clear why (matching) probability is not (population) frequency and why uncertainty intervals on matching probabilities are merely confused thinking. Forensic matching calculations should be based on a model, on stipulated premises. The model inevitably only approximates reality, and any error in the results comes only from error in the model, the inexactness of the approximation. Sampling variation does not measure that inexactness and hence is not helpful in explaining evidence and is in fact an impediment. Alternative haplotype matching probability approaches that various authors have considered are reviewed. Some are based on no model and cannot be taken seriously. For the others, some evaluation of the models is discussed. Recent evidence supports the adequacy of the simple exchangability model on which the kappa method rests. However, to make progress toward forensic calculation of Y haplotype mixture evidence a different tack is needed. The "Laplace distribution" model of Andersen et al. [3] which estimates haplotype frequencies by identifying haplotype clusters in population data looks useful. PMID:24315614

Brenner, Charles H



Welcome to Probability by Surprise  

NSDL National Science Digital Library

Several applets that demonstrate concepts of probability using graphics and animations are presented on this Web site. Rather than getting into the details of specific theories, the applets avoid heavy number crunching and instead expose the user to example situations that generalize probabilistic concepts. This can be beneficial by letting the user see the effects of certain principles and infer how they will hold in other situations. One of the most basic applets is the Say Red Applet, which demonstrates how repeatedly choosing one of two equally likely outcomes will result in breaking even on the number of right and wrong guesses. Other applets, such as the one dealing with conditional probabilities, are more elaborate. The only criticism of this site is its lack of instructions for using the applets; however, most are quite self explanatory.


Welcome to Probability by Surprise  

NSDL National Science Digital Library

Several applets that demonstrate concepts of probability using graphics and animations are presented on this Web site. Rather than getting into the details of specific theories, the applets avoid heavy number crunching and instead expose the user to example situations that generalize probabilistic concepts. This can be beneficial by letting the user see the effects of certain principles and infer how they will hold in other situations. One of the most basic applets is the Say Red Applet, which demonstrates how repeatedly choosing one of two equally likely outcomes will result in breaking even on the number of right and wrong guesses. Other applets, such as the one dealing with conditional probabilities, are more elaborate. The only criticism of this site is its lack of instructions for using the applets; however, most are quite self explanatory.



Smooth, Volume-Accurate Material Interface Reconstruction  

Microsoft Academic Search

A new material interface reconstruction method for volume fraction data is presented. Our method is comprised of two components: first, we generate initial interface topology; then, using a combination of smoothing and volumetric forces within an active interface model, we iteratively transform the initial material interfaces into high-quality surfaces that accurately approximate the problem's volume fractions. Unlike all previous work,

John C. Anderson; Christoph Garth; Mark A. Duchaineau; Kenneth I. Joy



Miniature telemetry system accurately measures pressure  

NASA Technical Reports Server (NTRS)

Miniature, low power, telemetry system that can be used with commercially available strain gage pressure transducers accurately measures pressure with a small implantable pressure cell and transmitter. The system has been used to date only with pressure transducers, but the circuit is equally applicable to any measurement using a strain gage sensor.

Fryer, T. B.



More Accurate and Fast SYN Flood Detection  

Microsoft Academic Search

SYN flood attacks still dominate distributed denial of service attacks. It is a great challenge to accurately detect the SYN flood attacks in high speed networks. An intelligent attacker would evade the public detection methods by suitably spoofing the attack to pretend to be benign. Keeping per-flow or per-connection state could eliminate such a spoofing, but meanwhile, it also consumes

Changhua Sun; Chengchen Hu; Yi Tang; Bin Liu



A simple, accurate voltage to frequency converter  

Microsoft Academic Search

A simple yet accurate voltage to frequency convertor is described and its performance examined. The unit requires a stable clock frequency. Conversion is linear, predictable, and practically independent of temperature to within errors of measurement (0.05%). Power drain is low (<150 mu W).

P. J. Ross



Accurate energy differences with Quantum Monte Carlo  

Microsoft Academic Search

Computation of accurate energy differences is of primary importance in the study of transformations as those occurring in solid to solid phase transitions or chemical reactions. In stochastic quantum simulations this can be done efficiently, employing correlated sampling techniques whereby fluctuations cancel with each other leading to results with a much smaller statistical error. Although correlated sampling is very effective

Simone Chiesa; David Ceperley; Jeongnim Kim; Richard Martin



Robust Accurate Statistical Annotation of General Text  

Microsoft Academic Search

We describe a robust accurate domain-independent approach to statistical parsing incorporated into the new release of the ANLT toolkit, and publicly available as a research tool. The system has been used to parse many well known corpora in order to produce data for lexical acquisition efforts; it has also been used as a component in an open-domain question answering project.

Ted Briscoe; John Carroll



Emergency Department Medication Lists Are Not Accurate  

Microsoft Academic Search

Background: Medication errors are a common source of adverse events. Errors in the home medication list may impact care in the Emergency Department (ED), the hospital, and the home. Medication reconciliation, a Joint Commission requirement, begins with an accurate home medication list. Objective: To evaluate the accuracy of the ED home medication list. Methods: Prospective, observational study of patients aged

Selin Caglar; Philip L. Henneman; Fidela S. Blank; Howard A. Smithline; Elizabeth A. Henneman



Accurate blemish detection with active contour models  

Microsoft Academic Search

This paper presents a novel image analysis scheme for accurate detection of fruit blemishes. The detection procedure consists of two steps: initial segmentation and refinement. In the first step, blemishes are coarsely segmented out with a flooding algorithm and in the second step an active contour model, i.e. a snake algorithm, is applied to refine the segmentation so that the

Qingsheng Yang; John A. Marchant




E-print Network

to synthesise speech from articulator positions based on the search of a database composed of pairsACCURATE SPECTRAL ENVELOPE ESTIMATION FOR ARTICULATION­TO­SPEECH SYNTHESIS Yoshinori Shiga and Simon King Centre for Speech Technology Research, University of Edinburgh, U.K. yoshi

Edinburgh, University of


Accurate Synthetic Generation of Realistic Personal Information  

E-print Network

Accurate Synthetic Generation of Realistic Personal Information Agus Pudjijono and Peter Christen Department of Computer Science, The Australian National University, Canberra ACT 0200, Australia peter, or social security numbers. Privacy and confidentiality are of great concern when such data is being

Christen, Peter



E-print Network

.3 Laws of Expectation, 67 4.4 Mean and Median, 71 #12;2 4.5 Variance, 73 4.6 A Law of Large Numbers, 75 4 on alien probabilities for diagnoses, 62 3.4.2 Updating on alien factors for diagnoses, 62 3.5 Softcore, in which the colors are all the real numbers from 0 to 1. The question of the precise relationship between

Fienberg, Stephen E.


JSTOR: Annals of Applied Probability  

NSDL National Science Digital Library

This journal from The Institute of Mathematical Statistics is now available online. Annals of Applied Probability, Vols. 1-3 (1991-1993)is fully accessible to the hundreds of academic institutions participating in JSTOR. The journal may be searched by keyword, full-text, title, author, and abstract, or browsed by date of publication. A list of JSTOR participants is provided at the JSTOR site.



Data Analysis: Probability and Technology  

NSDL National Science Digital Library

This series of three computer based lesson plans requires students to create specific virtual spinners and complete numerous trials in order to determine the difference between theoretical and experimental probability. By completing a large number of trials students discover the law of large numbers. In the third activity students create their own spinner and determine the likelihood of each event. The lesson plan includes a link to the Virtual Spinner which is cataloged separately. All worksheets are included for these activities.



Recurrent atlantoaxial instability due to fracture of the posterior C1 ring: a late finding following posterior C1-C2 fusion using the Halifax clamp.  


Although its use has fallen out of favor, the Halifax interlaminar clamp was used for many years to treat cervical instability through a posterior approach. Numerous complications, the majority of which are related to hardware failure, have been reported with the use of the interlaminar clamps and have led to the development of alternative techniques for posterior fusion, such as transarticular screw fixation. This report presents a case of recurrent atlantoaxial instability due to fracture of the posterior C1 ring that occurred 12 years after a posterior C1-C2 fusion with Halifax clamps. To the authors' knowledge, this is the first case report of symmetric fractures through the posterior C1 ring lateral to the site of the Halifax clamps, resulting in recurrent atlantoaxial instability. This report focuses on the surgical management of this complication and provides a review of the literature that pertains to complications following the use of the Halifax clamp to treat atlantoaxial instability. PMID:19327267

Rihn, Jeffrey A; Winegar, Corbett D; Donaldson, William F; Lee, Joon Y; Kang, James D



Cortical blindness following posterior lumbar decompression and fusion.  


Perioperative vision loss following non-ocular surgery is a well-documented phenomenon. In particular, perioperative vision loss has been frequently cited following spinal surgery. Although the rate of vision compromise in spinal surgery is relatively low, the consequences can be quite severe and devastating for the patient. We report a 60-year-old woman who initially presented with back and left leg pain as well as paraparesis. Imaging studies of the lumbar spine showed bony erosion consistent with tumor infiltration of the L3 and L4 spinal segments. Laminectomy at the L2-L4 levels for decompression of the intraspinal tumor was performed. Pathology of the resected bone was consistent with metastatic adenocarincoma. Postoperatively, the patient suffered severe anemia and bilateral infarctions of the posterior cerebral arteries and occipital lobes resulting in vision compromise. Although a definitive pathogenesis remains unknown, preoperative cardiovascular issues and intraoperative hemodynamic instabilities have typically been implicated as high risk factors. High risk factors for this novel clinical presentation of visual compromise following posterior lumbar laminectomy with decompression for an intraspinal tumor are reported. PMID:23791834

Agarwal, Nitin; Hansberry, David R; Goldstein, Ira M



Skipping Posterior Dynamic Transpedicular Stabilization for Distant Segment Degenerative Disease  

PubMed Central

Objective. To date, there is still no consensus on the treatment of spinal degenerative disease. Current surgical techniques to manage painful spinal disorders are imperfect. In this paper, we aimed to evaluate the prospective results of posterior transpedicular dynamic stabilization, a novel surgical approach that skips the segments that do not produce pain. This technique has been proven biomechanically and radiologically in spinal degenerative diseases. Methods. A prospective study of 18 patients averaging 54.94 years of age with distant spinal segment degenerative disease. Indications consisted of degenerative disc disease (57%), herniated nucleus pulposus (50%), spinal stenosis (14.28%), degenerative spondylolisthesis (14.28%), and foraminal stenosis (7.1%). The Oswestry Low-Back Pain Disability Questionnaire and visual analog scale (VAS) for pain were recorded preoperatively and at the third and twelfth postoperative months. Results. Both the Oswestry and VAS scores showed significant improvement postoperatively (P < 0.05). We observed complications in one patient who had spinal epidural hematoma. Conclusion. We recommend skipping posterior transpedicular dynamic stabilization for surgical treatment of distant segment spinal degenerative disease. PMID:23091736

Solmaz, Bilgehan; Aydin, Ahmet Levent; Gomleksiz, Cengiz; Ataker, Yaprak; Sasani, Mehdi; Oktenoglu, Tunc; Ozer, Ali Fahir



Vestibular and visual responses in human posterior insular cortex.  


The central hub of the cortical vestibular network in humans is likely localized in the region of posterior lateral sulcus. An area characterized by responsiveness to visual motion has previously been described at a similar location and named posterior insular cortex (PIC). Currently it is not known whether PIC processes vestibular information as well. We localized PIC using visual motion stimulation in functional magnetic resonance imaging (fMRI) and investigated whether PIC also responds to vestibular stimuli. To this end, we designed an MRI-compatible caloric stimulation device that allowed us to stimulate bithermally with hot temperature in one ear and simultaneously cold temperature in the other or with warm temperatures in both ears for baseline. During each trial, participants indicated the presence or absence of self-motion sensations. We found activation in PIC during periods of self motion when vestibular stimulation was carried out with minimal visual input. In combined visual-vestibular stimulation area PIC was activated in a similar fashion during congruent and incongruent stimulation conditions. Our results show that PIC not only responds to visual motion but also to vestibular stimuli related to the sensation of self motion. We suggest that PIC is part of the cortical vestibular network and plays a role in the integration of visual and vestibular stimuli for the perception of self motion. PMID:25185806

Frank, Sebastian M; Baumann, Oliver; Mattingley, Jason B; Greenlee, Mark W



Distinct value signals in anterior and posterior ventromedial prefrontal cortex.  


The core feature of an economic exchange is a decision to trade one good for another, based on a comparison of relative value. Economists have long recognized, however, that the value an individual ascribes to a good during decision making (i.e., their relative willingness to trade for that good) does not always map onto the reward they actually experience. Here, we show that experienced value and decision value are represented in distinct regions of ventromedial prefrontal cortex (VMPFC) during the passive consumption of rewards. Participants viewed two categories of rewards-images of faces that varied in their attractiveness and monetary gains and losses-while being scanned using functional magnetic resonance imaging. An independent market task, in which participants exchanged some of the money that they had earned for brief views of attractive faces, determined the relative decision value associated with each category. We found that activation of anterior VMPFC increased with increasing experienced value, but not decision value, for both reward categories. In contrast, activation of posterior VMPFC predicted each individual's relative decision value for face and monetary stimuli. These results indicate not only that experienced value and decision value are represented in distinct regions of VMPFC, but also that decision value signals are evident even in the absence of an overt choice task. We conclude that decisions are made by comparing neural representations of the value of different goods encoded in posterior VMPFC in a common, relative currency. PMID:20164333

Smith, David V; Hayden, Benjamin Y; Truong, Trong-Kha; Song, Allen W; Platt, Michael L; Huettel, Scott A



Left posterior temporal regions are sensitive to auditory categorization.  


Recent studies suggest that the left superior temporal gyrus and sulcus (LSTG/S) play a role in speech perception, although the precise function of these areas remains unclear. Here, we test the hypothesis that regions in the LSTG/S play a role in the categorization of speech phonemes, irrespective of the acoustic properties of the sounds and prior experience of the listener with them. We examined changes in functional magnetic resonance imaging brain activation related to a perceptual shift from nonphonetic to phonetic analysis of sine-wave speech analogs. Subjects performed an identification task before scanning and a discrimination task during scanning with phonetic (P) and nonphonetic (N) sine-wave sounds, both before (Pre) and after (Post) being exposed to the phonetic properties of the P sounds. Behaviorally, experience with the P sounds induced categorical identification of these sounds. In the PostP > PreP and PostP > PostN contrasts, an area in the posterior LSTG/S was activated. For both P and N sounds, the activation in this region was correlated with the degree of categorical identification in individual subjects. The results suggest that these areas in the posterior LSTG/S are sensitive neither to the acoustic properties of speech nor merely to the presence of phonetic information, but rather to the listener's awareness of category representations for auditory inputs. PMID:18284339

Desai, Rutvik; Liebenthal, Einat; Waldron, Eric; Binder, Jeffrey R



The right posterior paravermis and the control of language interference  

PubMed Central

Auditory and written language in humans' comprehension necessitates attention to the message of interest and suppression of interference from distracting sources. Investigating the brain areas associated with the control of interference is challenging because it is inevitable that activation of the brain regions that control interference co-occurs with activation related to interference per se. To isolate the mechanisms that control verbal interference, we used a combination of structural and functional imaging techniques in Italian and German participants who spoke English as a second language. First, we searched structural MRI images of Italian participants for brain regions where brain structure correlated with the ability to suppress interference from the unattended dominant language (Italian) while processing heard sentences in their weaker language (English). This revealed an area in the posterior paravermis of the right cerebellum where grey matter density was higher in individuals who were better at controlling verbal interference. Second, we found functional activation in the same region when our German participants made semantic decisions on written English words in the presence of interference from unrelated words in their dominant language (German). This combination of structural and functional imaging therefore highlights the contribution of the right posterior paravermis to the control of verbal interference. We suggest that the importance of this region for language processing has previously been missed because most fMRI studies limit the field of view to increase sensitivity; with the lower part of the cerebellum being the most likely region to be excluded. PMID:21775616

Filippi, Roberto; Richardson, Fiona M.; Dick, Frederic; Leech, Robert; Green, David W.; Thomas, Michael S.C.; Price, Cathy J.



Branch retinal artery occlusion associated with posterior uveitis  

PubMed Central

Background The purpose of this study is to report the clinical features and visual outcome of branch retinal artery occlusion (BRAO) associated with posterior uveitis. This is a retrospective study including the 18 eyes of 18 patients. All patients underwent a complete ophthalmic evaluation. Fundus photography, fluorescein angiography, and visual field testing were performed in all cases. Results Diseases associated with BRAO included active ocular toxoplasmosis in 7 patients, rickettsiosis in 4, Behçet’s uveitis in 2, West Nile virus infection in 1, idiopathic retinal vasculitis in 1, Crohn’s disease in 1, ocular tuberculosis in 1, and idiopathic retinal vasculitis, aneurysms, and neuroretinitis syndrome in 1 patient. The mean initial visual acuity was 20/50. BRAO involved the first order retinal artery in 33.3% of the eyes, the second order retinal artery in 33.3%, an arteriole in 27.8%, and a cilioretinal artery in 5.5%. The macula was involved in 44.4% of the eyes and an acute focus of retinitis or retinochoroiditis was associated to BRAO in 55.5%. Repermeabilization of the occluded artery occurred in all patients with permanent scotomas in the corresponding visual field. The mean visual acuity at last visit was 20/32. Conclusions BRAO, with subsequent visual impairment, may occur in the eyes with posterior uveitis. Physicians should be aware of such vision-threatening complication of infectious and inflammatory eye diseases. PMID:23514435



Patella maltracking in posterior-stabilized total knee arthroplasty.  


Maltracking of the patella component in total knee arthroplasty usually leads to complications such as subluxation, dislocation, fracture, excessive wear, or implant failure. After using a new posterior-stabilized total knee arthroplasty and a specific protocol for the patellofemoral articulation we determined the incidence of lateral retinacular release and patella complications. We retrospectively reviewed 255 consecutive primary posterior-stabilized total knee arthroplasties with an anatomic femoral component and a three-peg offset-dome patella. Component alignment was achieved using Whiteside's lines for the femoral component, the medial border of the tubercle for the tibial component, and previously reported techniques for the patella. Lateral release was performed in 15 knees (6.2%), most of which had excessive preoperative valgus (mean, 15 degrees). There were no reoperations for the patellofemoral joint at a mean followup of 3.7 years (range, 2-7 years). Two patients had asymptomatic osteonecrosis of the patella with complete radiolucent lines, and one patella fracture was treated with immobilization. We believe patella maltracking a largely avoidable problem in total knee arthroplasty. We found a low incidence of lateral retinacular release and patella complications using these components and this protocol for the patellofemoral articulation. PMID:16936588

Lachiewicz, Paul F; Soileau, Elizabeth S



Posterior foss avenous angiomas with drainage through the brain stem  

SciTech Connect

To describe 11 cases of posterior fossa venous angiomas with drainage through the brain stem. Eleven cases of posterior fossa venous angioma with drainage through the brain stem were evaluated using MR. Correlation with known routes of venous drainage for the cerebellum and brain stem is made. Six of the 11 venous angiomas were found in the cerebellum, four in the brain stem; one involved both the cerebellum and brain stem. The cerebellar venous angiomas drained to subependymal veins about the fourth ventricle and dorsal pons. These then connected with an enlarged transmesencephalic or transpontine vein, to drain anteriorly to the anterior pontine veins. The brain stem angiomas had variable drainage depending on location. Evidence of hemorrhage was seen in five cases. Cerebellar and brain stem venous angiomas have several potential routes of drainage, including an enlarged vein traversing the pons, midbrain, or medulla. A knowledge of the normal venous anatomy of this region helps to understand the occurrence of these uncommon routes of venous drainage. 15 refs., 8 figs., 1 tab.

Damiano, T.R.; Truwit, C.L. (Fitzsimons Army Medical Center, Aurora, CO (United States)); Dowd, C.F. (Univ. of California, San Francisco, CA (United States)); Symonds, D.L. (Denver General Hospital, CO (United States))



(Con)text-specific effects of visual dysfunction on reading in posterior cortical atrophy.  


Reading deficits are a common early feature of the degenerative syndrome posterior cortical atrophy (PCA) but are poorly understood even at the single word level. The current study evaluated the reading accuracy and speed of 26 PCA patients, 17 typical Alzheimer's disease (tAD) patients and 14 healthy controls on a corpus of 192 single words in which the following perceptual properties were manipulated systematically: inter-letter spacing, font size, length, font type, case and confusability. PCA reading was significantly less accurate and slower than tAD patients and controls, with performance significantly adversely affected by increased letter spacing, size, length and font (cursive < non-cursive), and characterised by visual errors (69% of all error responses). By contrast, tAD and control accuracy rates were at or near ceiling, letter spacing was the only perceptual factor to influence reading speed in the same direction as controls, and, in contrast to PCA patients, control reading was faster for larger font sizes. The inverse size effect in PCA (less accurate reading of large than small font size print) was associated with lower grey matter volume in the right superior parietal lobule. Reading accuracy was associated with impairments of early visual (especially crowding), visuoperceptual and visuospatial processes. However, these deficits were not causally related to a universal impairment of reading as some patients showed preserved reading for small, unspaced words despite grave visual deficits. Rather, the impact of specific types of visual dysfunction on reading was found to be (con)text specific, being particularly evident for large, spaced, lengthy words. These findings improve the characterisation of dyslexia in PCA, shed light on the causative and associative factors, and provide clear direction for the development of reading aids and strategies to maximise and sustain reading ability in the early stages of disease. PMID:24841985

Yong, Keir X X; Shakespeare, Timothy J; Cash, Dave; Henley, Susie M D; Warren, Jason D; Crutch, Sebastian J



(Con)text-specific effects of visual dysfunction on reading in posterior cortical atrophy  

PubMed Central

Reading deficits are a common early feature of the degenerative syndrome posterior cortical atrophy (PCA) but are poorly understood even at the single word level. The current study evaluated the reading accuracy and speed of 26 PCA patients, 17 typical Alzheimer's disease (tAD) patients and 14 healthy controls on a corpus of 192 single words in which the following perceptual properties were manipulated systematically: inter-letter spacing, font size, length, font type, case and confusability. PCA reading was significantly less accurate and slower than tAD patients and controls, with performance significantly adversely affected by increased letter spacing, size, length and font (cursive < non-cursive), and characterised by visual errors (69% of all error responses). By contrast, tAD and control accuracy rates were at or near ceiling, letter spacing was the only perceptual factor to influence reading speed in the same direction as controls, and, in contrast to PCA patients, control reading was faster for larger font sizes. The inverse size effect in PCA (less accurate reading of large than small font size print) was associated with lower grey matter volume in the right superior parietal lobule. Reading accuracy was associated with impairments of early visual (especially crowding), visuoperceptual and visuospatial processes. However, these deficits were not causally related to a universal impairment of reading as some patients showed preserved reading for small, unspaced words despite grave visual deficits. Rather, the impact of specific types of visual dysfunction on reading was found to be (con)text specific, being particularly evident for large, spaced, lengthy words. These findings improve the characterisation of dyslexia in PCA, shed light on the causative and associative factors, and provide clear direction for the development of reading aids and strategies to maximise and sustain reading ability in the early stages of disease. PMID:24841985

Yong, Keir X.X.; Shakespeare, Timothy J.; Cash, Dave; Henley, Susie M.D.; Warren, Jason D.; Crutch, Sebastian J.



Gluteus medius: an intramuscular EMG investigation of anterior, middle and posterior segments during gait.  


Previous electromyographic (EMG) studies of gluteus medius (GMed) have not accurately quantified the function of the three proposed structurally and functionally unique segments (anterior, middle and posterior). Therefore this study used anatomically verified locations for intramuscular electrode recordings in three segments of GMed to determine whether the segments are functionally independent. Bipolar fine wire electrodes were inserted into each segment of GMed in 15 healthy individuals. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions (MVICs) in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle using ANOVA. The relative contributions of each segment to the MVIC trials were compared with non-parametric tests. All segments showed a biphasic response during the stance phase of gait. There were no differences in amplitude variables (% MVIC) between segments, but the anterior segment had a later peak during both the first and second bursts.For the MVIC trials, there were significant differences in amplitude between segments in four of the five test positions. These data indicate that GMed is composed of three functionally independent segments. This study contributes to the theoretical understanding of the role of GMed. PMID:23587766

Semciw, Adam I; Pizzari, Tania; Murley, George S; Green, Rodney A



Thermoelectrical modeling of bipolar coagulation on posterior spinal artery in a porcine spinal surgery model.  


The primary objective of our study was to develop a thermoelectrical model with both solid and liquid phases to calculate tissue temperature during bipolar coagulation of a posterior spinal artery on the spinal cord. Control of thermal spread caused by coagulation is a concern in spinal surgery. This model utilizes a nonisothermal flow to account for the heat transfer due to the movement of cerebrospinal fluid that is induced by electrical field and temperature gradient. The model is validated by in situ temperature measurements on a porcine spinal cord model. The maximum error for tissue temperature of this model is 12.6%, and the overall average error is 4.2%. The lesional region (>50°C) is identified to be as wide as 5 mm, and thermal dose cumulative equivalent minutes at 43°C (CEM 43) is also calculated with this model. The incorporation of nonisothermal flow has been shown to be crucial in order to accurately predict thermal dose in tissue. The developed model can be further used to establish a guideline for the use of bipolar coagulation. PMID:23963190

Chen, Roland K; Than, Khoi D; Park, Paul; Shih, Albert J



A general method to calculate dose to spine in opposing anterior posterior treatment setup without CT.  


The spinal cord is usually part of the treatment volume in the treatment of the thorax and abdomen areas using antero-posterior (AP) and postero-anterior (PA) ports. Thus it is necessary to know the dose the spinal cord would receive. One needs to locate the spine to calculate the dose at that location. In the absence of CT, a set of orthogonal films is taken at simulation to aid in locating the spine. The relative point dose then is calculated using irregular field point dose calculation mode of the treatment planning system. The data needed for the calculation are the x and y coordinates of the spine in the coronal plane, air gap, and depth in tissue. Correct entry of these is thus important to obtain the dose accurately. Planning systems assume that the spine is close to the beam axis. There could be possible mislocation of the spine when this assumption is not valid. This presentation describes a procedure to obtain the needed numbers for a general location without any assumptions. To obtain x and y coordinates the suggestion is made to solve numerically using successive approximation series for the coordinates, the series continued until mutually consistent values are obtained. The other parameters, g and d, are obtained from the source to skin distance (SSD) above the spine point, with the use of multiple transaxial contours in association with the principle of linear interpolation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8369095

Janakiraman, R



Primary and submovement control of aiming in C6 tetraplegics following posterior deltoid transfer  

PubMed Central

Background Upper limb motor control in fast, goal-directed aiming is altered in tetraplegics following posterior-deltoid musculotendinous transfer. Specifically, movements have similar end-point accuracy but longer duration and lower peak velocity than those of age-matched, neurotypical controls. Here, we examine in detail the interplay between primary movement and submovement phases in five C6 tetraplegic and five control participants. Methods Aiming movements were performed in two directions (20 cm away or toward), with or without vision. Trials that contained a submovement phase (i.e., discontinuity in velocity, acceleration or jerk) were identified. Discrete kinematic variables were then extracted on the primary and submovements phases. Results The presence of submovements did not differ between the tetraplegic (68%) and control (57%) groups, and almost all submovements resulted from acceleration and jerk discontinuities. Tetraplegics tended to make a smaller amplitude primary movement, which had lower peak velocity and greater spatial variability at peak velocity. This was followed by a larger amplitude and longer duration secondary submovement. Peak velocity of primary movement was not related to submovement incidence. Together, the primary and submovement phases of both groups were equally effective in reducing end-point error. Conclusions C6 tetraplegic participants exhibit some subtle differences in measures of motor behaviour compared to control participants, but importantly feedforward and feedback processes work effectively in combination to achieve accurate goal-directed aiming. PMID:25055852



Computational modeling of drug distribution in the posterior segment of the eye: effects of device variables and positions.  


A computational model was developed to simulate drug distribution in the posterior segment of the eye after intravitreal injection and ocular implantation. The effects of important factors in intravitreal injection such as injection time, needle gauge and needle angle on the ocular drug distribution were studied. Also, the influences of the position and the type of implant on the concentration profile in the posterior segment were investigated. Computational Fluid Dynamics (CFD) calculations were conducted to describe the 3D convective-diffusive transport. The geometrical model was constructed based on the human eye dimensions. To simulate intravitreal injection, unlike previous studies which considered the initial shape of the injected drug solution as a sphere or cylinder, the more accurate shape was obtained by level-set method in COMSOL. The results showed that in intravitreal injection the drug concentration profile and its maximum value depended on the injection time, needle gauge and penetration angle of the needle. Considering the actual shape of the injected solution was found necessary to obtain the real concentration profile. In implant insertion, the vitreous cavity received more drugs after intraocular implantation, but this method was more invasive compared to the periocular delivery. Locating the implant in posterior or anterior regions had a significant effect on local drug concentrations. Also, the shape of implant influenced on concentration profile inside the eye. The presented model is useful for optimizing the administration variables to ensure optimum therapeutic benefits. Predicting and quantifying different factors help to reduce the possibility of tissue toxicity and to improve the treatment efficiency. PMID:24946303

Jooybar, Elaheh; Abdekhodaie, Mohammad J; Farhadi, Fatolla; Cheng, Yu-Ling



Comparison of the operation of arthroscopic tibial inlay and traditional tibial inlay for posterior cruciate ligament reconstruction  

PubMed Central

Objective: To perform dual-bundle reconstruction of posterior cruciate ligament using full arthroscopic tibial inlay technology with self-designed tibia tunnel drilling system and to compare the effect of arthroscopic tibial inlay versus traditional technique for posterior cruciate ligament reconstruction. Material and methods: 32 patients were randomly divided into experiment group (improved tibial inlay, n = 17) and control group (traditional tibial inlay, n = 15). Self-designed tibia tunnel drill system was used to produce intraoperative deep-limited bone tunnel. During follow-up, the location of the bone block and the healing situation were checked by knee X-ray and spiral CT scan. Blood loss, operation time and nerve vascular injuries were evaluated. Results: Mean intraoperative blood loss was 123.53 ± 74.05 ml in the improved tibial inlay group compared with 332 ± 114.26 ml in the traditional tibial inlay group (t = 6.12, P < 0.05). Mean operation time was 235.27 ± 58.88 min in the improved tibial inlay group compared with 346.37 ± 59.67 min in the traditional tibial inlay group (t = 5.19, P < 0.05). Posterior drawer test were negative in 15 cases, slight positive in 2 with improved tibial inlay technique compared with 14 negative cases and 2 positive cases of traditional tibial Inlay technique. The X-ray and spiral CT scan showed the location of the bone block were perfect and healed well with the patent who received improved tibial inlay technology after 12 weeks postoperatively. Conclusion: Accurate depth-limited bone tunnel can be produced by the tibia tunnel drill system with minor trauma, less bleeding and reducing of nerves or vessels and the recent clinical effects of PCL reconstruction were pretty good.

Lu, Daifeng; Xiao, Mochao; Lian, Yongyun; Zhou, Yong; Liu, Xuefeng



Differentiating Phonotactic Probability and Neighborhood Density in Adult Word Learning  

PubMed Central

Purpose The purpose of this study was to differentiate effects of phonotactic probability, the likelihood of occurrence of a sound sequence, and neighborhood density, the number of words that sound similar to a given word, on adult word learning. A second purpose was to determine what aspect of word learning (viz., triggering learning, formation of an initial representation, or integration with existing representations) was influenced by each variable. Method Thirty-two adults were exposed to 16 nonwords paired with novel objects in a story context. The nonwords orthogonally varied in phonotactic probability and neighborhood density. Learning was measured following 1, 4, and 7 exposures in a picture-naming task. Partially correct (i.e., 2 of 3 phonemes correct) and completely correct responses (i.e., 3 of 3 phonemes correct) were analyzed together and independently to examine emerging and partial representations of new words versus complete and accurate representations of new words. Results Analysis of partially correct and completely correct responses combined showed that adults learned a lower proportion of high-probability nonwords than low-probability nonwords (i.e., high-probability disadvantage) and learned a higher proportion of high-density nonwords than low-density nonwords (i.e., high-density advantage). Separate analysis of partially correct responses yielded an effect of phonotactic probability only, whereas analysis of completely correct responses yielded an effect of neighborhood density only. Conclusions These findings suggest that phonological and lexical processing influence different aspects of word learning. In particular, phonotactic probability may aid in triggering new learning, whereas neighborhood density may influence the integration of new lexical representations with existing representations. PMID:17197489

Storkel, Holly L.; Armbruster, Jonna; Hogan, Tiffany P.



Illustrating Basic Probability Calculations Using "Craps"  

ERIC Educational Resources Information Center

Instructors may use the gambling game of craps to illustrate the use of a number of fundamental probability identities. For the "pass-line" bet we focus on the chance of winning and the expected game length. To compute these, probabilities of unions of disjoint events, probabilities of intersections of independent events, conditional probabilities…

Johnson, Roger W.



Reset Switching Probability of Resistive Switching Devices  

Microsoft Academic Search

The reset switching probability of resistive switching devices is characterized in array testing. The measured switching probability can be quantitatively explained based on the mecha- nism of a thermally activated reset process. An analytical model of switching probability is developed to describe the dependence of reset probability on operation parameters, including applied voltage, selection transistor gate voltage, and pulsewidth. The

An Chen; Ming-Ren Lin



Objective and Subjective Probabilities in Quantum Mechanics  

E-print Network

The concept of probability was prominent in the original foundations of quantum mechanics, and continues to be so today. Indeed, the controversies regarding objective and subjective interpretations of probability have again become active. I argue that, although both objective and subjective probabilities have domains of relevance in QM, their roles are quite distinct. Even where both are legitimate, the objective and subjective probabilities differ, both conceptually and numerically. There are quantum probabilities that have no useful subjective interpretations, and there are subjective probabilities that cannot be realized as quantum probabilities.

Leslie Ballentine



Accurate Guitar Tuning by Cochlear Implant Musicians  

PubMed Central

Modern cochlear implant (CI) users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ?30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task. PMID:24651081

Lu, Thomas; Huang, Juan; Zeng, Fan-Gang



Accurate method for determining photometric linearity.  


Accurate photometric measurements depend on the linearity of the detection system, i.e., whether the output is strictly proportional to the incident light flux. The usual method for checking linearity is to introduce filters of known absorption into the optical path. Unfortunately, the many possible errors inherent in this method make it difficult to determine linearity in this way to better than 1%. By using three polarizers in series, keeping the axes of the outer two parallel and rotating the middle polarizer, it is possible to eliminate most of these sources of error. If polarizers of the highest quality are used, photometric linearity may be determined to better than 0.1%. Accurate values for the transmission of standard filters can also be determined with this instrument. The technique is particularly useful for calibrating filters having large optical densities. An error analysis and some experimental results obtained using a three-polarizer system are given. PMID:20057523

Bennett, H E



Accurate mask model for advanced nodes  

NASA Astrophysics Data System (ADS)

Standard OPC models consist of a physical optical model and an empirical resist model. The resist model compensates the optical model imprecision on top of modeling resist development. The optical model imprecision may result from mask topography effects and real mask information including mask ebeam writing and mask process contributions. For advanced technology nodes, significant progress has been made to model mask topography to improve optical model accuracy. However, mask information is difficult to decorrelate from standard OPC model. Our goal is to establish an accurate mask model through a dedicated calibration exercise. In this paper, we present a flow to calibrate an accurate mask enabling its implementation. The study covers the different effects that should be embedded in the mask model as well as the experiment required to model them.

Zine El Abidine, Nacer; Sundermann, Frank; Yesilada, Emek; Ndiaye, El Hadji Omar; Mishra, Kushlendra; Paninjath, Sankaranarayanan; Bork, Ingo; Buck, Peter; Toublan, Olivier; Schanen, Isabelle



Probability of Detection Demonstration Transferability  

NASA Technical Reports Server (NTRS)

The ongoing Mars Science Laboratory (MSL) Propellant Tank Penetrant Nondestructive Evaluation (NDE) Probability of Detection (POD) Assessment (NESC activity) has surfaced several issues associated with liquid penetrant POD demonstration testing. This presentation lists factors that may influence the transferability of POD demonstration tests. Initial testing will address the liquid penetrant inspection technique. Some of the factors to be considered in this task are crack aspect ratio, the extent of the crack opening, the material and the distance between the inspection surface and the inspector's eye.

Parker, Bradford H.



Accurate determination of the geoid undulation N  

NASA Astrophysics Data System (ADS)

This work is related to the activities of the CERGOP Study Group Geodynamics of the Balkan Peninsula, presents a method for the determination of the variation ?N and, indirectly, of the geoid undulation N with an accuracy of a few millimeters. It is based on the determination of the components xi, eta of the deflection of the vertical using modern geodetic instruments (digital total station and GPS receiver). An analysis of the method is given. Accuracy of the order of 0.01arcsec in the estimated values of the astronomical coordinates ? and ? is achieved. The result of applying the proposed method in an area around Athens is presented. In this test application, a system is used which takes advantage of the capabilities of modern geodetic instruments. The GPS receiver permits the determination of the geodetic coordinates at a chosen reference system and, in addition, provides accurate timing information. The astronomical observations are performed through a digital total station with electronic registering of angles and time. The required accuracy of the values of the coordinates is achieved in about four hours of fieldwork. In addition, the instrumentation is lightweight, easily transportable and can be setup in the field very quickly. Combined with a stream-lined data reduction procedure and the use of up-to-date astrometric data, the values of the components xi, eta of the deflection of the vertical and, eventually, the changes ?N of the geoid undulation are determined easily and accurately. In conclusion, this work demonstrates that it is quite feasible to create an accurate map of the geoid undulation, especially in areas that present large geoid variations and other methods are not capable to give accurate and reliable results.

Lambrou, E.; Pantazis, G.; Balodimos, D. D.



Documentation must be complete and accurate.  


If discharge documentation isn't complete and accurate, coders may not use the correct discharge status code, which could affect a hospital's reimbursement. Discharge status codes identify where patients go after discharge. If patients go to some settings before the geometric mean length of stay, a hospital may receive reduced reimbursement. The Centers for Medicare & Medicaid Services has also issued a new set of discharge status codes that indicate scheduled readmissions. PMID:24946381



Fast accurate missing SNP genotype local imputation  

PubMed Central

Background Single nucleotide polymorphism (SNP) genotyping assays normally give rise to certain percents of no-calls; the problem becomes severe when the target organisms, such as cattle, do not have a high resolution genomic sequence. Missing SNP genotypes, when related to target traits, would confound downstream data analyses such as genome-wide association studies (GWAS). Existing methods for recovering the missing values are successful to some extent – either accurate but not fast enough or fast but not accurate enough. Results To a target missing genotype, we take only the SNP loci within a genetic distance vicinity and only the samples within a similarity vicinity into our local imputation process. For missing genotype imputation, the comparative performance evaluations through extensive simulation studies using real human and cattle genotype datasets demonstrated that our nearest neighbor based local imputation method was one of the most efficient methods, and outperformed existing methods except the time-consuming fastPHASE; for missing haplotype allele imputation, the comparative performance evaluations using real mouse haplotype datasets demonstrated that our method was not only one of the most efficient methods, but also one of the most accurate methods. Conclusions Given that fastPHASE requires a long imputation time on medium to high density datasets, and that our nearest neighbor based local imputation method only performed slightly worse, yet better than all other methods, one might want to adopt our method as an alternative missing SNP genotype or missing haplotype allele imputation method. PMID:22863359



SOPROLIFE System: An Accurate Diagnostic Enhancer  

PubMed Central

Objectives. The aim of this study was to evaluate a light-emitting diode fluorescence tool, the SOPROLIFE light-induced fluorescence evaluator, and compare it to the international caries detection and assessment system-II (ICDAS-II) in the detection of occlusal caries. Methods. A total of 219 permanent posterior teeth in 21 subjects, with age ranging from 15 to 65 years, were examined. An intraclass correlation coefficient (ICC) was computed to assess the reliability between the two diagnostic methods. Results. The results showed a high reliability between the two methods (ICC = 0.92; IC = 0.901–0.940; P < 0.001). The SOPROLIFE blue fluorescence mode had a high sensitivity (87%) and a high specificity (99%) when compared to ICDAS-II. Conclusion. Compared to the most used visual method in the diagnosis of occlusal caries lesions, the finding from this study suggests that SOPROLIFE can be used as a reproducible and reliable assessment tool. At a cut-off point, categorizing noncarious lesions and visual change in enamel, SOPROLIFE shows a high sensitivity and specificity. We can conclude that financially ICDAS is better than SOPROLIFE. However SOPROLIFE is easier for clinicians since it is a simple evaluation of images. Finally in terms of efficiency SOPROLIFE is not superior to ICDAS but tends to be equivalent with the same advantages.

Zeitouny, Mona; Feghali, Mireille; Nasr, Assaad; Abou-Samra, Philippe; Saleh, Nadine; Bourgeois, Denis; Farge, Pierre



Mass spectrometric charting of bovine posterior/intermediate pituitary peptides.  

PubMed Central

The feasibility for charting neuropeptides in neuroendocrine tissues on the basis of the universal property and inherent specificity of their molecular weights was explored. As a model, a comprehensive MS analysis of extractable peptides from bovine posterior/intermediate pituitary was performed. Two suitable MS techniques--namely, plasma-desorption time-of-flight and fast atom bombardment MS--were evaluated, and each method could identify more than 20 peptides, including N-terminally acetylated and C-terminally amidated species. In toto these peptides account for almost the entire lengths of propressophysin, prooxyphysin, and proopiomelanocortin. Some of the experimentally determined molecular weights did not match any known peptides. Three of these species were identified as acidic joining peptide (4-24) [proopiomelanocortin(83-103)], C-terminal glycopeptide(22-39) [propressophysin(130-147)], and glycosylated C-terminal glycopeptide(1-19) [propressophysin(109-127)] by conventional sequence analysis. PMID:2762311

Feistner, G J; H?jrup, P; Evans, C J; Barofsky, D F; Faull, K F; Roepstorff, P



Disrupting posterior cingulate connectivity disconnects consciousness from the external environment.  


Neurophysiological and neuroimaging studies including both patients with disorders of consciousness and healthy subjects with modified states of consciousness suggest a crucial role of the medial posteroparietal cortex in conscious information processing. However no direct neuropsychological evidence supports this hypothesis and studies including patients with restricted lesions of this brain region are almost non-existent. Using direct intraoperative electrostimulations, we showed in a rare patient that disrupting the subcortical connectivity of the left posterior cingulate cortex (PCC) reliably induced a breakdown in conscious experience. This acute phenomenon was mainly characterized by a transient behavioral unresponsiveness with loss of external connectedness. In all cases, when he regained consciousness, the patient described himself as in dream, outside the operating room. This finding suggests that functional integrity of the PPC connectivity is necessary for maintaining consciousness of external environment. PMID:24508051

Herbet, Guillaume; Lafargue, Gilles; de Champfleur, Nicolas Menjot; Moritz-Gasser, Sylvie; le Bars, Emmanuelle; Bonnetblanc, François; Duffau, Hugues



Posterior approach (Kraske procedure) for surgical treatment of presacral tumors  

PubMed Central

Presacral tumors are rare, but can comprise a great variety of histological types. Congenital tumors are the most common. Once the diagnosis is established, surgical resection is essential because of the potential for malignancy or infection. Previous biopsy is not necessary or may be even harmful. To decide the best surgical approach (abdominal, sacral or combined) an individual and multidisciplinary analysis must be carried out. We report three cases of cystic presacral masses in which a posterior approach (Kraske procedure) enabled complete resection, the only way to decrease local recurrence. All patients had a satisfactory recovery. A brief overview of retrorectal tumors is presented, focusing on classification, clinical presentation, diagnosis and surgical management. PMID:22655127

Aranda-Narváez, José Manuel; González-Sánchez, Antonio Jesús; Montiel-Casado, Custodia; Sánchez-Pérez, Belinda; Jiménez-Mazure, Carolina; Valle-Carbajo, Marta; Santoyo-Santoyo, Julio



Posterior reversible encephalopathy syndrome (PRES) and CT perfusion changes  

PubMed Central

Posterior reversible encephalopathy syndrome (PRES) can present with focal neurologic deficits, mimicking a stroke and can often represent a diagnostic challenge when presenting atypically. A high degree of suspicion is required in the clinical setting in order to yield the diagnosis. Cerebral CT perfusion (CTP) is utilized in many institutions as the first line in acute stroke imaging. CTP has proved to be a very sensitive measure of cerebral blood flow dynamics, most commonly employed to delineate the infarcted tissue from penumbra (at-risk tissue) in ischemic strokes. But abnormal CTP is also seen in stroke mimics such as seizures, hypoglycemia, tumors, migraines and PRES. In this article we describe a case of PRES in an elderly bone marrow transplant recipient who presented with focal neurological deficits concerning for a cerebrovascular accident. CTP played a pivotal role in the diagnosis and initiation of appropriate management. We also briefly discuss the pathophysiology of PRES. PMID:22377097



Ganglioneuroblastoma of the posterior mediastinum: a case report  

PubMed Central

Introduction Ganglioneuroblastoma is a rare peripheral neuroblastic tumor that is derived from developing neuronal cells of the sympathetic nervous system, and is found mostly, but not exclusively, in babies and young children. Case presentation To the best of our knowledge, there have been no previously reported cases of ganglioneuroblastoma of the mediastinum from Pakistan. We present a case of ganglioneuroblastoma in an eight-year-old Pakistani Sindhi boy incidentally found to have a large posterior mediastinal mass that on biopsy initially looked like ganglioneuroma. He underwent successful excision of the mediastinal mass and remained stable post-operatively. Final pathology findings showed a ganglioneuroblastoma. He has remained free of symptoms on long-term follow-up. Conclusions The rarity of this tumor along with its almost exclusive occurrence in the pediatric population necessitates a thorough investigation of patients presenting with a symptomatic mass. PMID:21781292



Posterior spinal artery aneurysm rupture after 'Ecstasy' abuse.  


Posterior spinal artery (PSA) aneurysms are a rare cause of subarachnoid hemorrhage (SAH). The commonly abused street drug 3,4-methylenedioxymethamphetamine (MDMA) or 'Ecstasy' has been linked to both systemic and neurological complications. A teenager presented with neck stiffness, headaches and nausea after ingesting 'Ecstasy'. A brain CT was negative for SAH but a CT angiogram suggested cerebral vasculitis. A lumbar puncture showed SAH but a cerebral angiogram was negative. After a spinal MR angiogram identified abnormalities on the dorsal surface of the cervical spinal cord, a spinal angiogram demonstrated a left PSA 2?mm fusiform aneurysm. The patient underwent surgery and the aneurysmal portion of the PSA was excised without postoperative neurological sequelae. 'Ecstasy' can lead to neurovascular inflammation, intracranial hemorrhage, SAH and potentially even de novo aneurysm formation and subsequent rupture. PSA aneurysms may be treated by endovascular proximal vessel occlusion or open surgical excision. PMID:24994748

Johnson, Jeremiah; Patel, Shnehal; Saraf-Lavi, Efrat; Aziz-Sultan, Mohammad Ali; Yavagal, Dileep R



Asymptotic approximations to posterior distributions via conditional moment equations  

USGS Publications Warehouse

We consider asymptotic approximations to joint posterior distributions in situations where the full conditional distributions referred to in Gibbs sampling are asymptotically normal. Our development focuses on problems where data augmentation facilitates simpler calculations, but results hold more generally. Asymptotic mean vectors are obtained as simultaneous solutions to fixed point equations that arise naturally in the development. Asymptotic covariance matrices flow naturally from the work of Arnold & Press (1989) and involve the conditional asymptotic covariance matrices and first derivative matrices for conditional mean functions. When the fixed point equations admit an analytical solution, explicit formulae are subsequently obtained for the covariance structure of the joint limiting distribution, which may shed light on the use of the given statistical model. Two illustrations are given. ?? 2002 Biometrika Trust.

Yee, J. L.; Johnson, W. O.; Samaniego, F. J.



47 CFR 1.20004 - Maintaining secure and accurate records.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Maintaining secure and accurate records. 1.20004...Enforcement Act § 1.20004 Maintaining secure and accurate records. (a) A telecommunications carrier shall maintain a secure and accurate record of each...



High Frequency QRS ECG Accurately Detects Cardiomyopathy  

NASA Technical Reports Server (NTRS)

High frequency (HF, 150-250 Hz) analysis over the entire QRS interval of the ECG is more sensitive than conventional ECG for detecting myocardial ischemia. However, the accuracy of HF QRS ECG for detecting cardiomyopathy is unknown. We obtained simultaneous resting conventional and HF QRS 12-lead ECGs in 66 patients with cardiomyopathy (EF = 23.2 plus or minus 6.l%, mean plus or minus SD) and in 66 age- and gender-matched healthy controls using PC-based ECG software recently developed at NASA. The single most accurate ECG parameter for detecting cardiomyopathy was an HF QRS morphological score that takes into consideration the total number and severity of reduced amplitude zones (RAZs) present plus the clustering of RAZs together in contiguous leads. This RAZ score had an area under the receiver operator curve (ROC) of 0.91, and was 88% sensitive, 82% specific and 85% accurate for identifying cardiomyopathy at optimum score cut-off of 140 points. Although conventional ECG parameters such as the QRS and QTc intervals were also significantly longer in patients than controls (P less than 0.001, BBBs excluded), these conventional parameters were less accurate (area under the ROC = 0.77 and 0.77, respectively) than HF QRS morphological parameters for identifying underlying cardiomyopathy. The total amplitude of the HF QRS complexes, as measured by summed root mean square voltages (RMSVs), also differed between patients and controls (33.8 plus or minus 11.5 vs. 41.5 plus or minus 13.6 mV, respectively, P less than 0.003), but this parameter was even less accurate in distinguishing the two groups (area under ROC = 0.67) than the HF QRS morphologic and conventional ECG parameters. Diagnostic accuracy was optimal (86%) when the RAZ score from the HF QRS ECG and the QTc interval from the conventional ECG were used simultaneously with cut-offs of greater than or equal to 40 points and greater than or equal to 445 ms, respectively. In conclusion 12-lead HF QRS ECG employing RAZ scoring is a simple, accurate and inexpensive screening technique for cardiomyopathy. Although HF QRS ECG is highly sensitive for cardiomyopathy, its specificity may be compromised in patients with cardiac pathologies other than cardiomyopathy, such as uncomplicated coronary artery disease or multiple coronary disease risk factors. Further studies are required to determine whether HF QRS might be useful for monitoring cardiomyopathy severity or the efficacy of therapy in a longitudinal fashion.

Schlegel, Todd T.; Arenare, Brian; Poulin, Gregory; Moser, Daniel R.; Delgado, Reynolds



Lectures on probability and statistics  

SciTech Connect

These notes are based on a set of statistics lectures delivered at Imperial College to the first-year postgraduate students in High Energy Physics. They are designed for the professional experimental scientist. We begin with the fundamentals of probability theory, in which one makes statements about the set of possible outcomes of an experiment, based upon a complete a priori understanding of the experiment. For example, in a roll of a set of (fair) dice, one understands a priori that any given side of each die is equally likely to turn up. From that, we can calculate the probability of any specified outcome. We finish with the inverse problem, statistics. Here, one begins with a set of actual data (e.g., the outcomes of a number of rolls of the dice), and attempts to make inferences about the state of nature which gave those data (e.g., the likelihood of seeing any given side of any given die turn up). This is a much more difficult problem, of course, and one's solutions often turn out to be unsatisfactory in one respect or another.

Yost, G.P.



Regional Variations in Mechanical Strain in the Posterior Human Sclera  

PubMed Central

Purpose. The goal of this study was to establish sectorial and regional variability in the mechanical strain of peripapillary and mid-peripheral sclera in normal eyes from elderly human donors. Methods. Ten pairs of normal eyes from human donors aged 57 to 90 years old were mechanically inflation-tested within 48 hours post mortem. The intact posterior scleral shells were pressurized from 5 to 45 mm Hg while the full-field three-dimensional displacements of the scleral surface were measured using laser speckle interferometry. The displacement field was fit to continuous and differentiable analytical functions, from which the full strain tensor of the outer scleral surface was calculated. Mean maximum principal (tensile) strain was computed for eight circumferential sectors (45° wide) within the peripapillary and mid-peripheral regions surrounding the optic nerve head (ONH). Results. Overall, the peripapillary sclera exhibited significantly higher tensile strain (1.2%) than mid-peripheral sclera (0.95%) for a 40 mm Hg IOP elevation (P < 0.00001). In the peripapillary region, the inferotemporal sector exhibited the highest tensile strain (1.45%) while the superior sector had the lowest (1.19%; P < 0.00001). Mid-peripheral scleral strains were lower but exhibited a similar sectorial pattern. Conclusions. Human posterior sclera exhibits complex regional mechanical behavior in response to acute IOP elevations from 5 to 45 mm Hg. Results indicate 1) the peripapillary sclera is subjected to significantly higher tensile strain than the adjacent mid-peripheral sclera, and 2) strains are significantly higher in the temporal and inferior quadrants of the peripapillary sclera, which may contribute to the increased prevalence of glaucomatous damage associated with these regions of the ONH. PMID:22700704

Fazio, Massimo A.; Grytz, Rafael; Bruno, Luigi; Girard, Michael J. A.; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford




PubMed Central

Subcellular fractions of the bovine posterior pituitary, including one composed almost exclusively of pinched-off nerve endings (neurosecretosomes), were characterized electron microscopically, hormonally, and enzymically. 15% of the nerve terminals in the gland were isolated as neurosecretosomes, as estimated from determinations of lactic dehydrogenase, a soluble, cytoplasmic enzyme. Neurosecretosomes were subdivided into three fractions by density-gradient centrifugation. The three subfractions, each shown to be nearly homogeneous populations of neurosecretosomes by means of electron microscopic and enzymic criteria, differed from each other in their vasopressin/oxytocin (VP/OT) ratios. The VP/OT ratio increased from the lightest to the densest fraction, indicating that VP is localized to denser and OT to lighter neurosecretosomes; similar results have been obtained previously for subfractions of neurosecretory granules (NSG). No morphological differences were apparent in neurosecretosomes among the three subfractions. Although complete separation of VP and OT was not achieved, the findings suggest that VP and OT are each stored in a different species of nerve ending and support the hypothesis that a given neurosecretory cell synthesizes, stores, and secretes only one of the peptide hormones. Microvesicles, 40–80 mµ diameter and contained in typical neurosecretory cell terminals, are believed to be degradation products of membrane ghosts of depleted NSG; electron micrographs indicative of this transformation are presented. A fraction rich in microvesicles, but containing some NSG membranes, was prepared by density-gradient centrifugation of an osmolysate of neurosecretosomes. Smaller, apparently nonneurosecretory nerve endings, lacking NSG but filled with small vesicles, are occasionally seen in sections from whole gland. The vesicles in these atypical posterior pituitary nerve endings may be true neurohumor-containing, "synaptic" vesicles. PMID:6040535

Bindler, Elliot; Labella, Frank S.; Sanwal, Madhu



An investigation of the anatomic position of the posterior palatal seal by ultrasound.  


The posterior palatal seal contributes significantly to the retention of a maxillary complete denture. It is commonly considered to lie on the tissue covering the soft palate. However, no references are available to substantiate this correlation between the clinical and anatomic placement. This research used ultrasound instrumentation as a noninvasive procedure to locate the anatomic structures in the posterior palatal seal region of 15 maxillary edentulous patients. The posterior border was determined to lie on the tissue covering the soft palate. PMID:2646446

Narvekar, R M; Appelbaum, M B



[Acute multifocal posterior placoid pigment epitheliopathy and central retinal vein occlusion: association in a sarcoidosis patient].  


Acute multifocal posterior placoid pigment epitheliopathy is a chorioretinal inflammatory disease characterized by whitish lesions with ill-defined margins, deep to the retina and concentrated in the posterior pole. We report the case of a 17-year-old man who presented with the typical findings of bilateral acute multifocal posterior placoid pigment epitheliopathy. He developed secondary central retinal vein occlusion in the right eye. Systemic manifestations and additional investigations resulted in a diagnosis of sarcoidosis. PMID:24875817

Yakoubi, S; Kaibi, I; Krifa, F; Knani, L; Ben Haj Hmida, F



Open reduction and posterior instrumentation of type 3 high transverse sacral fracture-dislocation: technical note.  


The authors describe an open reduction and fixation through a posterior approach of Roy-Camille Type 3 transverse sacral fractures. This technique involves posterior staged reduction of the fracture applying distraction forces to restore the height, followed by posterior translation to restore sagittal alignment. Tips and pearls of this procedure, described for the first time in the literature, are also discussed in this report. PMID:24867310

Starantzis, Konstantinos A; Mirzashahi, Babak; Behrbalk, Eyal; Sadat, Mirmostafa; Shafafy, Masood