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1

The Estimation of Tree Posterior Probabilities Using Conditional Clade Probability Distributions

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

2013-01-01

2

How Accurately Does Current Fetal Imaging Identify Posterior Fossa Anomalies?

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, Adré J.

2009-01-01

3

Accurate Approximations for Posterior Moments and Marginal Densities

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

1986-01-01

4

Efficient Posterior Probability Mapping Using Savage-Dickey Ratios

Statistical Parametric Mapping (SPM) is the dominant paradigm for mass-univariate analysis of neuroimaging data. More recently, a Bayesian approach termed Posterior Probability Mapping (PPM) has been proposed as an alternative. PPM offers two advantages: (i) inferences can be made about effect size thus lending a precise physiological meaning to activated regions, (ii) regions can be declared inactive. This latter facility is most parsimoniously provided by PPMs based on Bayesian model comparisons. To date these comparisons have been implemented by an Independent Model Optimization (IMO) procedure which separately fits null and alternative models. This paper proposes a more computationally efficient procedure based on Savage-Dickey approximations to the Bayes factor, and Taylor-series approximations to the voxel-wise posterior covariance matrices. Simulations show the accuracy of this Savage-Dickey-Taylor (SDT) method to be comparable to that of IMO. Results on fMRI data show excellent agreement between SDT and IMO for second-level models, and reasonable agreement for first-level models. This Savage-Dickey test is a Bayesian analogue of the classical SPM-F and allows users to implement model comparison in a truly interactive manner. PMID:23533640

Penny, William D.; Ridgway, Gerard R.

2013-01-01

5

Mapping genes with longitudinal phenotypes via Bayesian posterior probabilities

Most association studies focus on disease risk, with less attention paid to disease progression or severity. These phenotypes require longitudinal data. This paper presents a new method for analyzing longitudinal data to map genes in both population-based and family-based studies. Using simulated systolic blood pressure measurements obtained from Genetic Analysis Workshop 18, we cluster the phenotype data into trajectory subgroups. We then use the Bayesian posterior probability of being in the high subgroup as a quantitative trait in an association analysis with genotype data. This method maintains high power (>80%) in locating genes known to affect the simulated phenotype for most specified significance levels (?). We believe that this method can be useful to aid in the discovery of genes that affect severity or progression of disease. PMID:25519410

2014-01-01

6

Probalign computes maximal expected accuracy multiple sequence alignments from partition function posterior probabilities. To date, Probalign is among the very best scoring methods on the BAliBASE, HOMSTRAD and OXBENCH benchmarks. Here, we introduce eProbalign, which is an online implementation of the approach. Moreover, the eProbalign web server doubles as an online platform for post-alignment analysis. The heart-and-soul of the post-alignment functionality is the Probalign Alignment Viewer applet, which provides users a convenient means to manipulate the alignments by posterior probabilities. The viewer can also be used to produce graphical and text versions of the output. The eProbalign web server and underlying Probalign source code is freely accessible at http://probalign.njit.edu. PMID:17485479

Chikkagoudar, Satish; Roshan, Usman; Livesay, Dennis

2007-07-01

7

Probalign computes maximal expected accuracy multiple sequence alignments from partition function posterior probabilities. To date, Probalign is among the very best scoring methods on the BAliBASE, HOMSTRAD and OXBENCH benchmarks. Here, we introduce eProbalign, which is an online implementation of the approach. Moreover, the eProbalign web server doubles as an online platform for post-alignment analysis. The heart-and-soul of the post-alignment functionality is the Probalign Alignment Viewer applet, which provides users a convenient means to manipulate the alignments by posterior probabilities. The viewer can also be used to produce graphical and text versions of the output. The eProbalign web server and underlying Probalign source code is freely accessible at http://probalign.njit.edu PMID:17485479

Chikkagoudar, Satish; Roshan, Usman; Livesay, Dennis

2007-01-01

8

Probalign computes maximal expected accuracy multiple sequence alignments from partition function posterior probabilities. To date, Probalign is among the very best scoring methods on the BAliBASE, HOMSTRAD, and OXBENCH benchmarks. Here, we introduce eProbalign, which is an online implementation of the approach. Moreover, the eProbalign webserver doubles as an online platform for post-alignment analysis. The heart-and-soul of the post-alignment functionality

Satish Chikkagoudar; Usman Roshan; Dennis R. Livesay

2007-01-01

9

An Accurate SER Estimation Method Based on Propagation Probability Ghazanfar Asadi and Mehdi B}@ece.neu.edu Abstract In this paper, we present an accurate but very fast soft error rate (SER) estimation technique, arise from energetic particles, namely neutrons and alpha particles. Soft Error Rate (SER) for a device

Paris-Sud XI, UniversitĂ© de

10

Background Identification of RNA homologs within genomic stretches is difficult when pairwise sequence identity is low or unalignable flanking residues are present. In both cases structure-sequence or profile/family-sequence alignment programs become difficult to apply because of unreliable RNA structures or family alignments. As such, local sequence-sequence alignment programs are frequently used instead. We have recently demonstrated that maximal expected accuracy alignments using partition function match probabilities (implemented in Probalign) are significantly better than contemporary methods on heterogeneous length protein sequence datasets, thus suggesting an affinity for local alignment. Results We create a pairwise RNA-genome alignment benchmark from RFAM families with average pairwise sequence identity up to 60%. Each dataset contains a query RNA aligned to a target RNA (of the same family) embedded in a genomic sequence at least 5K nucleotides long. To simulate common conditions when exact ends of an ncRNA are unknown, each query RNA has 5' and 3' genomic flanks of size 50, 100, and 150 nucleotides. We subsequently compare the error of the Probalign program (adjusted for local alignment) to the commonly used local alignment programs HMMER, SSEARCH, and BLAST, and the popular ClustalW program with zero end-gap penalties. Parameters were optimized for each program on a small subset of the benchmark. Probalign has overall highest accuracies on the full benchmark. It leads by 10% accuracy over SSEARCH (the next best method) on 5 out of 22 families. On datasets restricted to maximum of 30% sequence identity, Probalign's overall median error is 71.2% vs. 83.4% for SSEARCH (P-value < 0.05). Furthermore, on these datasets Probalign leads SSEARCH by at least 10% on five families; SSEARCH leads Probalign by the same margin on two of the fourteen families. We also demonstrate that the Probalign mean posterior probability, compared to the normalized SSEARCH Z-score, is a better discriminator of alignment quality. All datasets and software are available online. Conclusion We demonstrate, for the first time, that partition function match probabilities used for expected accuracy alignment, as done in Probalign, provide statistically significant improvement over current approaches for identifying distantly related RNA sequences in larger genomic segments. PMID:18226231

Roshan, Usman; Chikkagoudar, Satish; Livesay, Dennis R

2008-01-01

11

MLIP: using multiple processors to compute the posterior probability of linkage

Background Localization of complex traits by genetic linkage analysis may involve exploration of a vast multidimensional parameter space. The posterior probability of linkage (PPL), a class of statistics for complex trait genetic mapping in humans, is designed to model the trait model complexity represented by the multidimensional parameter space in a mathematically rigorous fashion. However, the method requires the evaluation of integrals with no functional form, making it difficult to compute, and thus further test, develop and apply. This paper describes MLIP, a multiprocessor two-point genetic linkage analysis system that supports statistical calculations, such as the PPL, based on the full parameter space implicit in the linkage likelihood. Results The fundamental question we address here is whether the use of additional processors effectively reduces total computation time for a PPL calculation. We use a variety of data – both simulated and real – to explore the question "how close can we get?" to linear speedup. Empirical results of our study show that MLIP does significantly speed up two-point log-likelihood ratio calculations over a grid space of model parameters. Conclusion Observed performance of the program is dependent on characteristics of the data including granularity of the parameter grid space being explored and pedigree size and structure. While work continues to further optimize performance, the current version of the program can already be used to efficiently compute the PPL. Thanks to MLIP, full multidimensional genome scans are now routinely being completed at our centers with runtimes on the order of days, not months or years. PMID:18541055

Govil, Manika; Segre, Alberto M; Vieland, Veronica J

2008-01-01

12

A simple, accurate method to calculate spread-spectrum multiple-access error probabilities

The exact calculation of error probabilities for direct-sequence spread-spectrum multiple-access (DS\\/SSMA) systems has been addressed in the literature. The exact calculation is computationally difficult, so emphasis has been on approximations and bounds. One particularly attractive approximation is to just use a signal-to-noise ratio in a Gaussian approximation, the `standard approximation'. Unfortunately, that approximation is not generally accurate enough. An improved

Jack M. Holtzman

1992-01-01

13

Background: Falls from height are one of the main causes of fatal occupational injuries. The objective of this study was to present a model for estimating occurrence probability of falling from height. Methods: In order to make a list of factors affecting falls, we used four expert group's judgment, literature review and an available database. Then the validity and reliability of designed questionnaire were determined and Bayesian networks were built. The built network, nodes and curves were quantified. For network sensitivity analysis, four types of analysis carried out. Results: A Bayesian network for assessment of posterior probabilities of falling from height proposed. The presented Bayesian network model shows the interrelationships among 37 causes affecting the falling from height and can calculate its posterior probabilities. The most important factors affecting falling were Non-compliance with safety instructions for work at height (0.127), Lack of safety equipment for work at height (0.094) and Lack of safety instructions for work at height (0.071) respectively. Conclusion: The proposed Bayesian network used to determine how different causes could affect the falling from height at work. The findings of this study can be used to decide on the falling accident prevention programs. PMID:25648498

Alizadeh, Seyed Shamseddin; Mortazavi, Seyed Bagher; Sepehri, Mohammad Mehdi

2014-01-01

14

Bayesian sensitivity analysis for posterior probability inferences in landslide hazard modeling

NASA Astrophysics Data System (ADS)

Landslides hazard modeling implies assumptions on prior conditional density functions of predisposing and triggering factors. The model uses beta distribution to calculate the prior and conditional probability density functions for landslides triggering factors. The landslides triggering factor is considered the soil water content. The model takes into consideration the seasonal changes in vegetation interception and runoff derived from Landsat satellite images (Landsat MSS, TM, ETM+). The satellite images were downloaded from http://earthexplorer.usgs.gov website with no regard to cloud cover. All the images were bulk processed for radiance and reflectance the LAI index for each image was extracted and used in the interception model and maximum likelihood algorithm was applied for vegetation delineation and classification, used in evapotranspiration model. The soil water content was modeled for a period of 30 years, starting in 1975 and ending in 2005, in the Breaza administrative area and Panatau administrative area, located in the Curvature Subcarpathians. For each landslide occurred in this time frame the modeled soil water content was retained and further statistical analysis were conducted

Cosmin Sandric, Ionut; Chitu, Zenaida

2013-04-01

15

NSDL National Science Digital Library

This is introduction into probability. This project allows students to explore with probability, the days following gives students a further look into probability. Today, you are going to experiment with probability. Go to the site An introduction into probability and read the first three sections, the last sections is the one with the picture of the coins. After you have read a little bit about probability, you now get to explore probability through some games. Start ...

Thompson, Ms.

2008-12-01

16

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.

2006-11-16

17

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.

2012-12-01

18

High posterior density ellipsoids of quantum states

NASA Astrophysics Data System (ADS)

Regions of quantum states generalize the classical notion of error bars. High posterior density (HPD) credible regions are the most powerful of region estimators. However, they are intractably hard to construct in general. This paper reports on a numerical approximation to HPD regions for the purpose of testing a much more computationally and conceptually convenient class of regions: posterior covariance ellipsoids (PCEs). The PCEs are defined via the covariance matrix of the posterior probability distribution of states. Here it is shown that PCEs are near optimal for the example of Pauli measurements on multiple qubits. Moreover, the algorithm is capable of producing accurate PCE regions even when there is uncertainty in the model.

Ferrie, Christopher

2014-02-01

19

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.

20

Fast and accurate probability density estimation in large high dimensional astronomical datasets

NASA Astrophysics Data System (ADS)

Astronomical surveys will generate measurements of hundreds of attributes (e.g. color, size, shape) on hundreds of millions of sources. Analyzing these large, high dimensional data sets will require efficient algorithms for data analysis. An example of this is probability density estimation that is at the heart of many classification problems such as the separation of stars and quasars based on their colors. Popular density estimation techniques use binning or kernel density estimation. Kernel density estimation has a small memory footprint but often requires large computational resources. Binning has small computational requirements but usually binning is implemented with multi-dimensional arrays which leads to memory requirements which scale exponentially with the number of dimensions. Hence both techniques do not scale well to large data sets in high dimensions. We present an alternative approach of binning implemented with hash tables (BASH tables). This approach uses the sparseness of data in the high dimensional space to ensure that the memory requirements are small. However hashing requires some extra computation so a priori it is not clear if the reduction in memory requirements will lead to increased computational requirements. Through an implementation of BASH tables in C++ we show that the additional computational requirements of hashing are negligible. Hence this approach has small memory and computational requirements. We apply our density estimation technique to photometric selection of quasars using non-parametric Bayesian classification and show that the accuracy of the classification is same as the accuracy of earlier approaches. Since the BASH table approach is one to three orders of magnitude faster than the earlier approaches it may be useful in various other applications of density estimation in astrostatistics.

Gupta, Pramod; Connolly, Andrew J.; Gardner, Jeffrey P.

2015-01-01

21

NSDL National Science Digital Library

What are the chances? What is probability? Math Glossary What are the chances that you will get a baby brother or a baby sister? Boy or Girl? If you flip more than one coin, what are the combinations you could get? What are the chances you will get each combination? Probability in Flipping Coins ...

Banks, Ms.

2005-05-11

22

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.

23

Posterior sampling with improved efficiency

The Markov Chain Monte Carlo (MCMC) technique provides a means to generate a random sequence of model realizations that sample the posterior probability distribution of a Bayesian analysis. That sequence may be used to make inferences about the model uncertainties that derive from measurement uncertainties. This paper presents an approach to improving the efficiency of the Metropolis approach to MCMC by incorporating an approximation to the covariance matrix of the posterior distribution. The covariance matrix is approximated using the update formula from the BFGS quasi-Newton optimization algorithm. Examples are given for uncorrelated and correlated multidimensional Gaussian posterior distributions.

Hanson, K.M.; Cunningham, G.S.

1998-12-01

24

NASA Astrophysics Data System (ADS)

Development of electron-hole exchange-correlation functional (eh-Exc) is challenging because of various factors such as distance dependent dielectric function, different effective masses, and presence of core/shell interfaces. Calculation of eh-recombination probability is also challenging because of its sensitivity to the form of the wavefunction at small electron-hole separation. This talk will focus on systematic development of eh-Exc to address these challenges. In this approach an orbital based functional is constructed by combining the strategy of direct minimization of the optimized effective potential (OEP) with the OEP-MBPT method. The eh-Exc functional was used for computational of exciton binding energy and eh-recombination in a series of CdSe qdots. Comparison of the eh-Exc results with pseudopotential+CI calculations, Kohn-Sham perturbation theory calculations, and experimental values will be presented. The results indicate that the search for the ground state densities can be restricted to a set of N-representable densities which satisfy the electron-hole Kato cusp condition. Assessment and benchmarking of the quality of the eh-recombination probability will be presented by comparing eh-Exc results with explicitly correlated methods such as PIMC and QMC calculations.

Chakraborty, Arindam; Blanton, Christopher

2013-03-01

25

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

2011-06-01

26

Purpose: To determine whether normal tissue complication probability (NTCP) analyses of the human spinal cord by use of the Lyman-Kutcher-Burman (LKB) model, supplemented by linear-quadratic modeling to account for the effect of fractionation, predict the risk of myelopathy from stereotactic radiosurgery (SRS). Methods and Materials: From November 2001 to July 2008, 24 spinal hemangioblastomas in 17 patients were treated with SRS. Of the tumors, 17 received 1 fraction with a median dose of 20 Gy (range, 18-30 Gy) and 7 received 20 to 25 Gy in 2 or 3 sessions, with cord maximum doses of 22.7 Gy (range, 17.8-30.9 Gy) and 22.0 Gy (range, 20.2-26.6 Gy), respectively. By use of conventional values for {alpha}/{beta}, volume parameter n, 50% complication probability dose TD{sub 50}, and inverse slope parameter m, a computationally simplified implementation of the LKB model was used to calculate the biologically equivalent uniform dose and NTCP for each treatment. Exploratory calculations were performed with alternate values of {alpha}/{beta} and n. Results: In this study 1 case (4%) of myelopathy occurred. The LKB model using radiobiological parameters from Emami and the logistic model with parameters from Schultheiss overestimated complication rates, predicting 13 complications (54%) and 18 complications (75%), respectively. An increase in the volume parameter (n), to assume greater parallel organization, improved the predictive value of the models. Maximum-likelihood LKB fitting of {alpha}/{beta} and n yielded better predictions (0.7 complications), with n = 0.023 and {alpha}/{beta} = 17.8 Gy. Conclusions: The spinal cord tolerance to the dosimetry of SRS is higher than predicted by the LKB model using any set of accepted parameters. Only a high {alpha}/{beta} value in the LKB model and only a large volume effect in the logistic model with Schultheiss data could explain the low number of complications observed. This finding emphasizes that radiobiological models traditionally used to estimate spinal cord NTCP may not apply to the dosimetry of SRS. Further research with additional NTCP models is needed.

Daly, Megan E.; Luxton, Gary [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Choi, Clara Y.H. [Department of Neurosurgery, Stanford University, Stanford, CA (United States); Gibbs, Iris C. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Chang, Steven D.; Adler, John R. [Department of Neurosurgery, Stanford University, Stanford, CA (United States); Soltys, Scott G., E-mail: sgsoltys@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, CA (United States)

2012-04-01

27

UNIFORM STABILITY OF POSTERIORS Sanjib Basu

UNIFORM STABILITY OF POSTERIORS by Sanjib Basu Northern Illinois University DeKalb, IL 60115, USA E M of probability measures. Stability then amounts to checking if these functions satisfy Lipschitz condition of order 1. For parametric prior families, an intuitive criterion of p--stability is proposed

Basu, Sanjib

28

Reversible posterior leukoencephalopathy syndrome

Reversible posterior leukoencephalopathy syndrome (RPLS) is characterized by subacute onset of headache, decreased alertness,\\u000a vomiting, seizures, visuoperceptual disturbances, together with bilateral white matter lesions in posterior brain regions\\u000a on brain imaging. The most frequently associated conditions related to RPLS are arterial hypertension and the use of immunosuppressive\\u000a or cytotoxic treatment. T2-, Fluid Attenuation Inversion Recovery (FLAIR), and Apparent Diffusion Coefficient

Dimitri Renard; Pierre Labauge; Rik Vandenberghe

2010-01-01

29

Horizontal posterior hamstring harvest.

Harvesting of the gracilis and semi-tendinosus (ST) hamstring tendons is usually performed by anteromedial approach. Harvesting by a horizontal posterior approach is possible. Based on a series of 90 patients, this technical note describes the perioperative difficulties and the characteristics of the harvested tendon(s) as well as any complications. Only one unsuccessful harvest was reported. Posterior harvesting of the gracilis and ST hamstring tendons is a reliable, reproducible surgical technique with a low rate of complications. PMID:25453925

Letartre, R; Isida, R; Pommepuy, T; Miletic, B

2014-12-01

30

Bayesian inference of a lake water quality model by emulating its posterior density

NASA Astrophysics Data System (ADS)

use a Gaussian stochastic process emulator to interpolate the posterior probability density of a computationally demanding application of the biogeochemical-ecological lake model BELAMO to accelerate statistical inference of deterministic model and error model parameters. The deterministic model consists of a mechanistic description of key processes influencing the mass balance of nutrients, dissolved oxygen, organic particles, and phytoplankton and zooplankton in the lake. This model is complemented by a Gaussian stochastic process to describe the remaining model bias and by Normal, independent observation errors. A small subsample of the Markov chain representing the posterior of the model parameters is propagated through the full model to get model predictions and uncertainty estimates. We expect this approximation to be more accurate at only slightly higher computational costs compared to using a Normal approximation to the posterior probability density and linear error propagation to the results as we did in an earlier paper. The performance of the two techniques is compared for a didactical example as well as for the lake model. As expected, for the didactical example, the use of the emulator led to posterior marginals of the model parameters that are closer to those calculated by Markov chain simulation using the full model than those based on the Normal approximation. For the lake model, the new technique proved applicable without an excessive increase in computational requirements, but we faced challenges in the choice of the design data set for emulator calibration. As the posterior is a scalar function of the parameters, the suggested technique is an alternative to the emulation of a potentially more complex, structured output of the simulation model that allows for the use of a less case-specific emulator. This is at the cost that still the full model has to be used for prediction (which can be done with a smaller, approximately independent subsample of the Markov chain).

Dietzel, A.; Reichert, P.

2014-10-01

31

[Locked posterior shoulder dislocation].

Posterior shoulder dislocations are diagnosed rarely in every-day practice. Although the methods of radiological imaging have been developing and becoming commonly available, the cases of late diagnosis are still happening. Proper clinical examination and properly conducted and interpretated radiographs allow for identification and implementation of appropriate medical procedures. In spite of fact that such cases are identified expectionally rarely, a few types of procedural have been analised and numerous therapeutic methods have been described. The choice of an appropriate treatment is complicated and requires in-depth theoretical knowledge as well as the knowledge of specific conditions within the shoulder surgery. Based on an algorithm, proposed by Griggs, between 2000-2006 seven patients with locked posterior instability were treated, for all of them defect of the proximal humerus did not exceed 30%. In all these cases the goals of improving stability and range of motion were obtained. PMID:18853661

Gadek, Artur; Slusarski, Jakub; Kasprzyk, Marcin; Ciszek, Elzbieta

2008-01-01

32

Acute injuries of the Achilles tendon are common among athletes and non-athletes alike. Injuries of other posterior calf muscles are far less common but should be considered in the differential, to ensure proper diagnosis and treatment of patients with calf injuries. This article focuses on these calf injuries, including injuries of the gastrocnemius, plantaris, soleus, and flexor hallucis longus, which may occasionally be mistaken for Achilles tendon disorders. PMID:19857847

Campbell, John T

2009-12-01

33

Sixteen months' experience with 140 posterior chamber intraocular lens implants.

Three main designs of posterior chamber lenses in 140 cases have been reviewed. The visual results are satisfactory; patient satisfaction is good; and postoperative complications are limited to anterior dislocation of the feet of the lens and the necessity to wash out cortical remnants from behind the prosthesis in a small percentage of cases. The posterior chamber prosthesis is free from some of the complications of other intraocular lenses and probably provides the most 'normal' looking eye of any pseudophakoi. Images PMID:871458

Pearce, J. L.

1977-01-01

34

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.

2008-01-01

35

NSDL National Science Digital Library

Probability is used to determine the likeliness of an event. Use these games to test your knowledge of this skill. You can adjust this spinner and determine the probability of the pointer landing in a certain sector. Try picking different colored marbles out of the box and determine the probability of each. Find the prize hidden behind each Door. ...

Cate, Ms.

2008-04-23

36

ERIC Educational Resources Information Center

Induced probabilities have been largely ignored by educational researchers. Simply stated, if a new or random variable is defined in terms of a first random variable, then induced probability is the probability or density of the new random variable that can be found by summation or integration over the appropriate domains of the original random…

Neel, John H.

37

NSDL National Science Digital Library

This probability application allows the learner to conduct a large volume of experimental trials using a die or an adjustable spinner. Conducting a large volume of trials will enable the learner to make comparisons between experimental and theoretical probability. Discussion topics and a worksheet on experimental probability are provided.

2012-01-01

38

35. Probability 1 35. PROBABILITY

). The cumulative distribution function F(a) is the probability that x a: F(a) = a - f(x) dx . (35.6) Here35. Probability 1 35. PROBABILITY Revised September 2011 by G. Cowan (RHUL). 35.1. General [1 the conditional probability P(A|B) (read P of A given B) as P(A|B) = P(A B) P(B) . (35.1) From this definition

39

New atomic transition probability measurements for 948 lines of Ti I are reported. Branching fractions from Fourier transform spectra and from spectra recorded using a 3 m echelle spectrometer are combined with published radiative lifetimes from laser-induced fluorescence measurements to determine these transition probabilities. Generally good agreement is found in comparisons to the NIST Atomic Spectra Database. The new Ti I data are applied to re-determine the Ti abundance in the photospheres of the Sun and metal-poor star HD 84937 using many lines covering a range of wavelength and excitation potential to explore possible non-local thermal equilibrium effects. The variation of relative Ti/Fe abundance with metallicity in metal-poor stars observed in earlier studies is supported in this study.

Lawler, J. E.; Guzman, A.; Wood, M. P. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)] [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sneden, C. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States)] [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Cowan, J. J., E-mail: jelawler@wisc.edu, E-mail: adrianaguzman2014@u.northwestern.edu, E-mail: mpwood@wisc.edu, E-mail: chris@verdi.as.utexas.edu, E-mail: cowan@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

2013-04-01

40

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.

41

Using Isoscapes to Model Probability Surfaces for Determining Geographic Origins

\\u000a This chapter describes a modeling framework for using isoscapes to describe probable geographic origins of sampled material.\\u000a The approach first inverts an isoscape model and then adds known or estimated components of variance to create a single continuous\\u000a posterior probability density that describes the probability of any given location as the origin. The posterior density is\\u000a defined analytically or by

Michael B. Wunder

42

NSDL National Science Digital Library

This site, created by the Department of Statistics at Yale University gives an explanation, a definition and an example of conditional probability. Topics include the probabilities of intersections of events and Bayes' formula. Overall, this is a great resource for any mathematics classroom studying statistics.

Lacey, Michelle

2008-12-23

43

Posterior Tibial Tendon Dysfunction (PTTD)

... ACFAS | Información en Espańol Advanced Search Home » Foot & Ankle Conditions » Posterior Tibial Tendon Dysfunction (PTTD) Text Size ... the arch, and an inward rolling of the ankle. As the condition progresses, the symptoms will change. ...

44

Posterior skull surgery in craniosynostosis

In 1984, two young infants with unusual “clover-leaf” patterns of skull deformity were treated by posterior skull-releasing surgery that dramatically improved their overall skull shape, to the extent that further operative intervention was not required. This focused our attention on the posterior skull and its role in craniosynostosis. In cases of multi-suture craniosynostosis and craniofacial syndromes severely raised intracranial pressure

S. Sgouros; J. H. Goldin; A. D. Hockley; M. J. C. Wake

1996-01-01

45

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.

2012-08-02

46

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.

2008-12-30

47

Confidence Probability versus Detection Probability

In a discovery sampling activity the auditor seeks to vet an inventory by measuring (or inspecting) a random sample of items from the inventory. When the auditor finds every sample item in compliance, he must then make a confidence statement about the whole inventory. For example, the auditor might say: ''We believe that this inventory of 100 items contains no more than 5 defectives with 95% confidence.'' Note this is a retrospective statement in that it asserts something about the inventory after the sample was selected and measured. Contrast this to the prospective statement: ''We will detect the existence of more than 5 defective items in this inventory with 95% probability.'' The former uses confidence probability while the latter uses detection probability. For a given sample size, the two probabilities need not be equal, indeed they could differ significantly. Both these probabilities critically depend on the auditor's prior belief about the number of defectives in the inventory and how he defines non-compliance. In other words, the answer strongly depends on how the question is framed.

Axelrod, M

2005-08-18

48

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.

2006-01-01

49

Posterior polar cataract: A review.

Posterior polar cataract is a rare form of congenital cataract. It is usually inherited as an autosomal dominant disease, yet it can be sporadic. Five genes have been attributed to the formation of this disease. It is highly associated with complications during surgery, such as posterior capsule rupture and nucleus drop. The reason for this high complication rate is the strong adherence of the opacity to the weak posterior capsule. Different surgical strategies were described for the handling of this challenging entity, most of which emphasized the need for gentle maneuvering in dealing with these cases. It has a unique clinical appearance that should not be missed in order to anticipate, avoid, and minimize the impact of the complications associated with it. PMID:23960967

Kalantan, Hatem

2012-01-01

50

[Treatment of posterior positional plagiocephaly].

In 1992, the American academy of paediatrics has recommended that infants be placed on their backs to sleep, because prone sleeping has been correlated with sudden infant death syndrome. Following this article, medical paediatric community has documented an exponential increase in the diagnosis of posterior cranial deformities, which were considered as the consequence of unrelieved pressure onto the occiput during infant sleep. These last 15 years, management of posterior positional plagiocephaly has evolved but is still not standardized; it varies according to local specificities, and medical or parental preferences. Treatment of deformational plagiocephaly includes preventive counseling, repositioning adjustments and exercises, physiotherapy, osteopathy, treatment by dynamic cranial orthosis. On extremely rare occasions, corrective surgery is proposed. This article aims at reviewing the epidemiologic, diagnostic, and various therapeutic options of posterior positional plagiocephaly. PMID:18952411

Vernet, O; de Ribaupierre, S; Cavin, B; Rilliet, B

2008-12-01

51

The Neuropsychiatric Profile of Posterior Cortical Atrophy.

We analyzed scores obtained at the Neuropsychiatric Inventory (NPI) by 20 patients with posterior cortical atrophy (PCA) and contrasted it with 20 patients having Alzheimer disease (AD). Patients with hallucinations and delusions were not included due to the high probability of a diagnosis of Lewy body disease. Prevalence of behavioral and psychological symptoms (BPSD) was 95% in the PCA group, the most frequent being apathy and anxiety. Cluster analysis on NPI subscales highlighted a behavioral subsyndrome characterized by agitated temper and irritability. Depression, anxiety, and apathy did not cluster with any other BPSD nor with each other. The PCA group showed a significantly higher proportion of anxious patients and worse anxiety score than patients with AD. No correlation was found between NPI data and demographic, clinical, or neuropsychological features nor were there significant differences for the same variables between anxious and nonanxious cases with PCA. In agreement with anecdotal reports, anxiety seems particularly relevant in PCA. PMID:25330926

Isella, Valeria; Villa, Giulia; Mapelli, Cristina; Ferri, Francesca; Appollonio, Ildebrando Marco; Ferrarese, Carlo

2014-10-20

52

The purpose of this study was to measure the strain in the posterior cruciate ligament as a function of knee flexion angle and posterior tibial slope following total knee arthroplasty with a posterior cruciate ligament-retaining design. Posterior cruciate ligament strain was measured in seven fresh-frozen cadavers for posterior tibial slopes of 10°, 8°, and 5°. For all three levels of

Robert Singerman; John C. Dean; Hector D. Pagan; Victor M. Goldberg

1996-01-01

53

Stereolithography for Posterior Fossa Cranioplasty

Posterior fossa cranioplasty has been suggested for improvement of neurological symptoms following craniectomy. However, there is no particular recommendation in the literature about techniques for prosthesis manufacture and implantation. We report our experience using rapid prototyping technology and stereolithography for pre-surgical implant design and production of cranioplasties. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:17171056

Agner, Celso; Dujovny, Manuel; Evenhouse, Raymond; Charbel, Fady T.; Sadler, Lewis

1998-01-01

54

This article was written for the Logic in Computer Science column in the February 2015 issue of the Bulletin of the European Association for Theoretical Computer Science. The intended audience is general computer science audience. The uncertainty principle asserts a limit to the precision with which position x and momentum p of a particle can be known simultaneously. You may know the probability distributions of x and p individually but the joint distribution makes no physical sense. Yet Wigner exhibited such a joint distribution f(x,p). There was, however, a little trouble with it: some of its values were negative. Nevertheless Wigner's discovery attracted attention and found applications. There are other joint distribution, all with negative values, which produce the correct marginal distributions of x and p. But only Wigner's distribution produces the correct marginal distributions for all linear combinations of position and momentum. We offer a simple proof of the uniqueness and discuss related issues.

Andreas Blass; Yuri Gurevich

2015-02-02

55

Posterior cruciate ligament of the knee (image)

The posterior cruciate ligament (PCL) is a powerful ligament extending from the top-rear surface of the tibia to the bottom-front surface of the femur. The ligament prevents the knee joint from posterior instability.

56

Nanotherapy for posterior eye diseases.

It is assumed that more than 50% of the most enfeebling ocular diseases have their origin in the posterior segment. Furthermore, most of these diseases lead to partial or complete blindness, if left untreated. After cancer, blindness is the second most dreaded disease world over. However, treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted for delivery to this segment. In this regard, nanostructured drug delivery systems are proposed to defy ocular barriers, target retina, and act as permeation enhancers in addition to providing a controlled release. Since an important step towards developing effective treatment strategies is to understand the course or a route a drug molecule needs to follow to reach the target site, the first part of the present review discusses various pathways available for effective delivery to and clearance from the posterior eye. Promise held by nanocarrier systems, viz. liposomes, nanoparticles, and nanoemulsion, for effective delivery and selective targeting is also discussed with illustrative examples, tables, and flowcharts. However, the applicability of these nanocarrier systems as self-administration ocular drops is still an unrealized dream which is in itself a huge technological challenge. PMID:24862316

Kaur, Indu Pal; Kakkar, Shilpa

2014-11-10

57

Approaches to a posterior polar cataract

Posterior polar cataracts present special challenges to the cataract surgeon. These are often associated with weakness/dehiscence of the posterior capsule and thus have a higher rate of intraoperative posterior capsule rupture. The surgeon needs to adhere to special surgical strategies to minimize the risk of a posterior capsule rupture. These include, adhering to the principles of closed chamber technique, avoiding hydrodissection – instead performing ‘inside-out’ hydrodelineation and using modest to low phaco parameters and reducing these stepwise. This article provides important pearls on how to approach a posterior polar cataract. PMID:23960968

Vasavada, Abhay R.; Vasavada, Viraj A.; Raj, Shetal M.

2011-01-01

58

Accurate GSM Indoor Localization

Accurate indoor localization has long been an objective of the ubiquitous computing research community, and numerous indoor lo- calization solutions based on 802.11, Bluetooth, ultrasound and infrared technologies have been proposed. This paper presents the first accurate GSM indoor localization system that achieves median accuracy of 5 me- ters in large multi-floor buildings. The key idea that makes accurate GSM-based

Veljo Otsason; Alex Varshavsky; Anthony Lamarca; Eyal De Lara

2005-01-01

59

Posterior Lamellar Keratoplasty in Perspective

\\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

60

Minimally Invasive Posterior Hamstring Harvest

Autogenous hamstring harvesting for knee ligament reconstruction is a well-established standard. Minimally invasive posterior hamstring harvest is a simple, efficient, reproducible technique for harvest of the semitendinosus or gracilis tendon or both medial hamstring tendons. A 2- to 3-cm longitudinal incision from the popliteal crease proximally, in line with the semitendinosus tendon, is sufficient. The deep fascia is bluntly penetrated, and the tendon or tendons are identified. Adhesions are dissected. Then, an open tendon stripper is used to release the tendon or tendons proximally; a closed, sharp tendon stripper is used to release the tendon or tendons from the pes. Layered, absorbable skin closure is performed, and the skin is covered with a skin sealant, bolster dressing, and plastic adhesive bandage for 2 weeks. PMID:24266003

Wilson, Trent J.; Lubowitz, James H.

2013-01-01

61

Face Recognition Based on the Probability Support Vector Machines

Face recognition is very important in intelligent meeting scenario. An approach to face recognition based on the probability support vector machines is proposed in this paper. In this approach, an approach of the posterior probability output of multi-class SVM is modeled. One-against-one multi-class SVMs with probability output are chosen as the classifiers for face recognition. Considering the real need of

Xiaoling Xiao; Layuan Li

2008-01-01

62

Cerebral Palsy Spasticity. Selective Posterior Rhizotomy

We have performed selective posterior rhizotomies on 60 children with cerebral palsy. The procedure involves lumbar laminectomy with stimulation of the rootlets (fascicles) of the second lumbar to the first sacral posterior roots bilaterally; those rootlets associated with an abnormal motor response, as evidenced by sustained or diffused muscular contraction, are divided leaving intact rootlets associated with a brief localized

Warwick J. Peacock; Leila J. Arens; Barbara Berman

1987-01-01

63

Seismic moment tensor inversion with posterior samples and uncertanties

NASA Astrophysics Data System (ADS)

We perform a grid search to estimate moment tensors, with uncertainties, for earthquakes in southern Alaska, Mw > 3.5. The earthquakes are modeled as double couple mechanisms, such that our five inversion parameters are four for the moment tensor (strike, dip, rake, Mw) and one for depth. Our inversion algorithm is based on the method of Zhu and Helmberger (1996), which attempts to fit synthetic and observed waveforms for body wave and surface wave components separately by using different bandpass filters and allowing for different time-shifts for effects of unmodeled three-dimensional (3D) structure. This misfit function is an unnormalized weighted L2 norm of integrated waveform differences. The misfit function is completely evaluated within the 5-dimensional model space. For most earthquakes, the misfit function in model space is quite smooth, which causes challenges for generating moment tensor samples of the posterior probability density and quantifying the uncertainty. We establish a scaling of the misfit function such that it generates 'reasonable' posterior samples. Using the posterior samples, we compute a single angle in moment tensor space that represents the uncertainty of the orientation of the moment tensor solution. We also relate the uncertainity estimate with the quality of the solution, measured in terms of variance reduction. Our uncertainty estimates are considerably larger than those reported in the literature for similar techniques. We have examined 50 earthquakes in detail and expect to complete a moment tensor catalog of over 100 earthquakes in southern Alaska.

Silwal, V.; Tape, C.

2013-12-01

64

Posterior Instrumentation for Occipitocervical Fusion

Since 1995, 29 consecutive patients with craniocervical spine instability due to several pathologies were managed with posterior occipitocervical instrumentation and fusion. Laminectomy was additionally performed in nineteen patients. The patients were divided in two groups: Group A which included patients managed with screw-rod instrumentation, and Group B which included patients managed with hook-and-screw-rod instrumentation. The patients were evaluated clinically and radiographically using the following parameters: spine anatomy and reconstruction, sagittal profile, neurologic status, functional level, pain relief, complications and status of arthrodesis. The follow-up was performed immediately postoperatively and at 2, 6, 12 months after surgery, and thereafter once a year. Fusion was achieved in all but one patient. One case of infection was the only surgery related complication. Neurological improvement and considerable pain relief occurred in the majority of patients postoperatively. There were neither intraoperative complications nor surgery related deaths. However, the overall death rate was 37.5% in group A, and 7.7% in group B. There were no instrument related failures. The reduction level was acceptable and was maintained until the latest follow-up in all of the patients. No statistical difference between the outcomes of screw-rod and hook-and-screw-rod instrumentation was detected. Laminectomy did not influence the outcome in either group. Screw-rod and hook-and-screw-rod occipitocervical fusion instrumentations are both considered as safe and effective methods of treatment of craniocervical instability. PMID:21772931

Sapkas, George; Papadakis, Stamatios A; Segkos, Dimitrios; Kateros, Konstantinos; Tsakotos, George; Katonis, Pavlos

2011-01-01

65

With decreased exposure in a minimal posterior hip incision, navigation with computer assistance provides an alternative method to accurately place the components. This study compares the results of a series of 82 navigated total hips to a retrospective cohort of 50 hips done with conventional instruments. The surgical incision split the gluteus maximus but did not extend distally into the

Richard L. Wixson; Margot A. MacDonald

2005-01-01

66

Adaptive approximation of higher order posterior statistics

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, E-mail: leew@maths.ox.ac.uk

2014-02-01

67

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

2009-01-01

68

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.

2004-10-15

69

ERIC Educational Resources Information Center

Grades matter. College grading systems, however, are often ad hoc and prone to mistakes. This essay focuses on one factor that contributes to high-quality grading systems: grading accuracy (or "efficiency"). I proceed in several steps. First, I discuss the elements of "efficient" (i.e., accurate) grading. Next, I present analytical results…

Rom, Mark Carl

2011-01-01

70

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.

2011-01-01

71

Random Variables Probability Distribution

Random Variables Probability Distribution Expected Value and Variance The Binomial Distribution Stat 491: Biostatistics Chapter 4: Discrete Probability Distributions Solomon W. Harrar The University of Montana Fall 2012 Chapter 4: Discrete Probability Distributions Stat 491: Biostatistics #12;Random

Bardsley, John

72

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.

1974-01-01

73

Passive Posterior Tibial Subluxation on Routine Knee MRI as a Secondary Sign of PCL Tear

The posterior drawer test is an accurate clinical test to diagnose posterior cruciate ligament (PCL), indicating laxity of the PCL that allows posterior tibial translation. This study aimed to determine whether posterior tibial translation relative to the femur on routine MRI could serve as an additional sign of PCL tear. Routine knee MRI in eleven patients (7 males, 4 females) with arthroscopically confirmed isolated PCL tears were reviewed independently by two musculoskeletal radiologists. Measurements of tibial translation were made in the medial and lateral compartments of patients and controls (10 males, 12 females) without clinical or MRI evidence of ligament injury. Significant medial compartment posterior tibial translation was present in patients with PCL tear compared to controls (+2.93?mm versus +0.03?mm, P = 0.002) with excellent interobserver agreement (intraclass correlation coefficient (ICC) = 0.94). No significant difference in lateral compartment tibial translation was observed (+0.17?mm versus ?0.57?mm, P = 0.366) despite excellent interobserver agreement (ICC = 0.96). Posterior tibial translation in the midmedial compartment may be a secondary sign of isolated PCL tear on routine knee MRI with passive extension without manipulation or weight bearing. Additional work in a larger cohort may better address the accuracy of this finding. PMID:25587446

Degnan, Andrew J.; Maldjian, Catherine; Adam, Richard J.; Harner, Christopher D.

2014-01-01

74

Unilateral posterior arch fractures of the atlas.

Unilateral posterior arch fractures of the atlas are discussed with two clinical examples and an experimental study of their mechanism. Laboratory fracturing of posterior arches of atlas specimens with a specially adapted universal testing machine produced nonsimultaneous fractures of the two sides in four of six specimens. In three of these specimens, a complete fracture on one side was temporarily displaced because the orientation of the leverage acting on the other side changed from sagittal to oblique. The consequent increase in the effective length of the lever arm reduced the angular deformation and strain on the second side. The second fracture occurred only after additional deflection of the posterior tubercle by up to 3 mm reproduced on the second side about the same angle of deformation that had caused the first fracture. A posterior arch fracture occurring by this mechanism will remain unilateral if the deflection is arrested before failure of the second side. PMID:6437181

Suss, R A; Bundy, K J

1984-01-01

75

Meibomian Gland Dysfunction and Treatment (Posterior Blepharitis)

... Meibomian Gland Dysfunction and Treatment What are Meibomian (Oil) Glands? Meibomian glands are glands that are arranged ... lashes. The force of an eyelid blink causes oil to be excreted onto the posterior lid margin. ...

76

Posterior Hip Pain in an Athletic Population

Context: Posterior hip pain is a relatively uncommon but increasingly recognized complaint in the orthopaedic community. Patient complaints and presentations are often vague or nonspecific, making diagnosis and subsequent treatment decisions difficult. The purposes of this article are to review the anatomy and pathophysiology related to posterior hip pain in the athletic patient population. Evidence Acquisition: Data were collected through a thorough review of the literature via a MEDLINE search of all relevant articles between 1980 and 2010. Results: Many patients who complain of posterior hip pain actually have pain referred from another part of the body—notably, the lumbar spine or sacroiliac joint. Treatment options for posterior hip pain are typically nonoperative; however, surgery is warranted in some cases. Conclusions: Recent advancements in the understanding of hip anatomy, pathophysiology, and treatment options have enabled physicians to better diagnosis athletic hip injuries and select patients for appropriate treatment. PMID:23015944

Frank, Rachel M.; Slabaugh, Mark A.; Grumet, Robert C.; Virkus, Walter W.; Bush-Joseph, Charles A.; Nho, Shane J.

2010-01-01

77

Posterior odds ratios for selected regression hypotheses

Summary Bayesian posterior odds ratios for frequently encountered hypotheses about parameters of the normal linear multiple regression\\u000a model are derived and discussed. For the particular prior distributions utilized, it is found that the posterior odds ratios\\u000a can be well approximated by functions that are monotonic in usual sampling theoryF statistics. Some implications of this finding and the relation of our work

A. Zellner; A. Siow

1980-01-01

78

Posterior tibial tendon dysfunction: a review.

Posterior tibial tendon dysfunction is a progressive deformity that can result in the development of a pathologic flatfoot deformity. Numerous publications have studied the effects of clinical interventions at specific stages of progression of posterior tibial tendon dysfunction, but there is still uncertainty regarding the clinical identification of the condition. It is clear that more information regarding the etiology, progression, and risk factors of posterior tibial tendon dysfunction is required. Clear evidence exists that suggests that the quality of life for patients with posterior tibial tendon dysfunction is significantly affected. Furthermore, evidence suggests that early conservative intervention can significantly improve quality of life regarding disability, function, and pain. This would suggest that significant cost burden reductions could be made by improving awareness of the condition, which would improve early diagnosis. Early conservative intervention may help reduce the number of patients requiring surgery. This review focuses on the etiologic factors, epidemiologic features, and pathogenesis of posterior tibial tendon dysfunction. It aims to analyze, discuss, and debate the current understanding of this condition using the available literature. In addition, there is a discussion of the evidence base surrounding disease characteristics associated with the different clinical stages of posterior tibial tendon dysfunction. PMID:21406702

Durrant, Beverley; Chockalingam, Nachiappan; Hashmi, Farina

2011-01-01

79

Accurate Unlexicalized Parsing

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

2003-01-01

80

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.

1996-01-01

81

A Bayesian Probability Calculus for Density Matrices

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

2014-08-09

82

Thoughts on Decision Making with Imprecise Probabilities Department of Philosophy

that her "posterior" views about the relative odds of propositions consistent with D agree with her "prior" views about these relative odds. 2 | Â· Gradational beliefs are often revealed in decisions. Rational credence same epistemic state. Â· The Urn1 and Urn2 probabilities are resilient. They remain fixed (exactly

Fitelson, Branden

83

Clinical evaluation of posterior canal benign paroxysmal positional vertigo

Background: Benign paroxysmal positional vertigo (BPPV) is a mechanical peripheral vestibular disorder which may involve any of the three semicircular canals but principally the posterior. In as much as the literature has described theories to explain the mechanism of BPPV and also contains scholarly works that elucidate BPPV; its management remains an enigma to most clinicians. To this end, this work was aimed at outlining an evidence-based best practice for most common form of BPPV. Materials and Methods: A systematic review of the literature was conducted between 1948 and June 2011 in PubMed, Embase, Ovid, and Cochrane database through the online Library of the University of Cape Town. Seventy-nine worthy articles that addressed the study were selected on consensus of the two authors. Conclusion: There is consensus for the use of canalith repositioning procedures as the best form of treatment for posterior canal canalolithiasis. However, successful treatment is dependent on accurate identification of the implicated canal and the form of lithiasis. Furthermore, clinicians should note that there is no place for pharmacological treatment of BPPV; unless it is to facilitate repositioning. PMID:23271854

Ibekwe, Titus S.; Rogers, C.

2012-01-01

84

Sm Transition Probabilities and Abundances

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 improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

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

2005-10-19

85

Probability Bracket Notation and Probability Modeling

Inspired by the Dirac notation, a new set of symbols, the Probability Bracket Notation (PBN) is proposed for probability modeling. By applying PBN to discrete and continuous random variables, we show that PBN could play a similar role in probability spaces as the Dirac notation in Hilbert vector spaces. The time evolution of homogeneous Markov chains with discrete-time and continuous-time are discussed in PBN. Our system state p-kets are identified with the probability vectors, while our system state p-bra can be identified with the Doi state function or the Peliti standard bra. We also suggest that, by transforming from the Schrodinger picture to the Heisenberg picture, the time-dependence of a system p-ket of a homogeneous MC can be shifted to the observable as a stochastic process.

Xing M. Wang

2009-09-07

86

Giant epidermoid cyst of the posterior neck.

A 49-year-old man was presented for evaluation of a painless mass on his right posterior neck. The mass had gradually enlarged for a 25-year period without inflammation or rupture. On physical examination, a round, nontender, soft-tissue mass, 8 cm in diameter, was noted on the right posterior neck. The neck is a common site of epidermoid cysts, but a mass more than 5 cm in diameter is rare. A contrast-enhanced neck computed tomographic (CT) scan revealed a 7.6 × 6.5 × 5.7 cm unilocular hypodense mass adjacent to the posterior neck muscles.The mass was completely excised under general anesthesia. A histopathologic examination of the excised specimen resulted in a diagnosis of an epidermoid cyst. The patient was discharged from the hospital on the third postoperative day. There were no recurrences in a 2-year follow-up period. PMID:21586972

Kim, Cheesun; Park, Myong Chul; Seo, Seung Jo; Yoo, Young Moon; Jang, Yu Jin; Lee, Il Jae

2011-05-01

87

Recently, several new techniques for anatomic posterior cruciate ligament reconstruction (PCLR) have emerged and are believed to restore the normal anatomy of the posterior cruciate ligament more accurately. Despite the latest trend, the optimal methods for anatomic PCLR remain controversial. The purpose of this research is to review surgical techniques for PCLR in cadaver studies and suggest consistent and reproducible technical criteria. For the review of the literature, MEDLINE and EMBASE were screened for articles on anatomic PCLR. Only basic science studies on PCLR performed on human cadavers and written in English were included. Seventeen studies were included in this systematic review. Only the tunnel positions, graft types, and surgical techniques were reported in the majority of the studies. There were many variations of the reported tunnel positions, graft types, and surgical techniques among the studies. In most studies, surgical techniques for consistent and reproducible anatomic PCLR were not explained clearly. Therefore, high level medical research should be encouraged in order to establish standard surgical techniques for anatomic PCLR. PMID:25505700

Lee, Dong Yeong; Kim, Dong Hee; Park, Jin Sung; Nam, Dae Cheol; Cho, Seong Hee; Jeong, Jin Hoon; Hwang, Sun Chul

2014-12-01

88

Accurate quantum chemical calculations

NASA Technical Reports Server (NTRS)

An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1989-01-01

89

Probability Learning and Aging.

ERIC Educational Resources Information Center

Examines the relationship between probability learning and aging by studying the performance of 48 young and 48 old adults in a probability learning task which used different reinforcement procedures and material rewards. (CM)

Winefield, A. H.; Mullins, G. P.

1980-01-01

90

NSDL National Science Digital Library

This probability lesson plan requires students to use probability vocabulary to describe events as likely, unlikely, equally likely, impossible, or certain. Students then use this information to help them conduct experiments and interpret probability as a fraction or on a number line as a value between 0 and 1. This lesson plan includes links to an online probability game (cataloged separately), an online quiz, and two documents (rtf) for student work.

2012-10-05

91

Arthroscopic posterior bone block procedure: a new technique using suture anchor fixation.

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-Béatrice; McClelland, Walter B; Thélu, Charles-Edouard; Schwartz, Daniel G

2013-11-01

92

Probability is sometimes regarded as a universal panacea for epistemology. It has been supposed that the rationality of belief is almost entirely a matter of probabilities. Unfortunately, those philosophers who have thought about this most extensively have tended to be probability theorists first, and epistemologists only secondarily. In my estimation, this has tended to make them insensitive to the complexities

John L. Pollock

1983-01-01

93

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

2010-08-23

94

Learning relational probability trees

Classification trees are widely used in the machine learning and data mining communities for modeling propositional data. Recent work has extended this basic paradigm to probability estimation trees. Traditional tree learning algorithms assume that instances in the training data are homogenous and independently distributed. Relational probability trees (RPTs) extend standard probability estimation trees to a relational setting in which data

Jennifer Neville; David Jensen; Lisa Friedland; Michael Hay

2003-01-01

95

In this paper, it is argued that probability theory, when used correctly, is sufficient for the task of reasoning under un- certainty. Since numerous authors have rejected probability as inadequate for various reasons, the bulk of the paper is aimed at refuting these claims and indicating the sources of error. In particular, the definition of probability as a mea- sure

Peter Cheeseman

1985-01-01

96

Both neural and behavioral responses to stimuli are influenced by the state of the brain immediately preceding their presentation, notably by pre-stimulus oscillatory activity. Using frequency analysis of high-density electroencephalogram coupled with source estimations, the present study investigated the role of pre-stimulus oscillatory activity in auditory spatial temporal order judgments (TOJ). Oscillations within the beta range (i.e. 18-23 Hz) were significantly stronger before accurate than inaccurate TOJ trials. Distributed source estimations identified bilateral posterior sylvian regions as the principal contributors to pre-stimulus beta oscillations. Activity within the left posterior sylvian region was significantly stronger before accurate than inaccurate TOJ trials. We discuss our results in terms of a modulation of sensory gating mechanisms mediated by beta activity. PMID:21056064

Bernasconi, Fosco; Manuel, Aurelie L; Murray, Micah M; Spierer, Lucas

2011-02-01

97

Dynamical Simulation of Probabilities

NASA Technical Reports Server (NTRS)

It has been demonstrated that classical probabilities, and in particular, probabilistic Turing machine, can be simulated by combining chaos and non-Lipschitz dynamics, without utilization of any man-made devices(such as random number generators). Self-orgainizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed. Special attention was focused upon coupled stochastic processes, defined in terms of conditional probabilities, for which joint probability does not exist. Simulations of quantum probabilities are also discussed.

Zak, Michail

1996-01-01

98

Posterior arch defects of the cervical spine

Spondylolysis and absence of the pedicle are congenital anomalies of the posterior cervical spine. Their roentgenographic changes may be confused with other more serious entities which may necessitate either emergent therapy or require extensive diagnostic testing and treatment. Four cases are present and the literature is reviewed. A hypothesis for the embryologic etiology of these entities is proposed.

Schwartz, A.M.; Wechsler, R.J.; Landy, M.D.; Wetzner, S.M.; Goldstein, S.A.

1982-05-01

99

Posterior predictive Bayesian phylogenetic model selection.

We present two distinctly different posterior predictive approaches to Bayesian phylogenetic model selection and illustrate these methods using examples from green algal protein-coding cpDNA sequences and flowering plant rDNA sequences. The Gelfand-Ghosh (GG) approach allows dissection of an overall measure of model fit into components due to posterior predictive variance (GGp) and goodness-of-fit (GGg), which distinguishes this method from the posterior predictive P-value approach. The conditional predictive ordinate (CPO) method provides a site-specific measure of model fit useful for exploratory analyses and can be combined over sites yielding the log pseudomarginal likelihood (LPML) which is useful as an overall measure of model fit. CPO provides a useful cross-validation approach that is computationally efficient, requiring only a sample from the posterior distribution (no additional simulation is required). Both GG and CPO add new perspectives to Bayesian phylogenetic model selection based on the predictive abilities of models and complement the perspective provided by the marginal likelihood (including Bayes Factor comparisons) based solely on the fit of competing models to observed data. PMID:24193892

Lewis, Paul O; Xie, Wangang; Chen, Ming-Hui; Fan, Yu; Kuo, Lynn

2014-05-01

100

Posterior plagiocephaly: craniosynostosis or skull molding?

The surgical indication in posterior plagiocephaly has been and still is a subject of discussion. Unlike other types of craniosynostosis, this particular type of cranial deformity does not show the typical radiological findings that are encountered in cases of prematurely fused cranial sutures. Furthermore, in most cases even the inspective evaluation during the surgical operation fails to demonstrate the actual

Concezio Di Rocco; Antonio Scogna; Franceso Velardi; Helder J. L. Zambelli

1998-01-01

101

Subspecialization in the human posterior medial cortex.

The posterior medial cortex (PMC) is particularly poorly understood. Its neural activity changes have been related to highly disparate mental processes. We therefore investigated PMC properties with a data-driven exploratory approach. First, we subdivided the PMC by whole-brain coactivation profiles. Second, functional connectivity of the ensuing PMC regions was compared by task-constrained meta-analytic coactivation mapping (MACM) and task-unconstrained resting-state correlations (RSFC). Third, PMC regions were functionally described by forward/reverse functional inference. A precuneal cluster was mostly connected to the intraparietal sulcus, frontal eye fields, and right temporo-parietal junction; associated with attention and motor tasks. A ventral posterior cingulate cortex (PCC) cluster was mostly connected to the ventromedial prefrontal cortex and middle left inferior parietal cortex (IPC); associated with facial appraisal and language tasks. A dorsal PCC cluster was mostly connected to the dorsomedial prefrontal cortex, anterior/posterior IPC, posterior midcingulate cortex, and left dorsolateral prefrontal cortex; associated with delay discounting. A cluster in the retrosplenial cortex was mostly connected to the anterior thalamus and hippocampus. Furthermore, all PMC clusters were congruently coupled with the default mode network according to task-unconstrained but not task-constrained connectivity. We thus identified distinct regions in the PMC and characterized their neural networks and functional implications. PMID:25462801

Bzdok, Danilo; Heeger, Adrian; Langner, Robert; Laird, Angela R; Fox, Peter T; Palomero-Gallagher, Nicola; Vogt, Brent A; Zilles, Karl; Eickhoff, Simon B

2015-02-01

102

Congenital orbital teratoma up to posterior fossa

Congenital orbital teratoma is a rare condition which presents as marked proptosis of eyeball in a newborn. It is rapidly progressive with secondary damage to eyeball due to pressure effect. This case presented by us is of interest due to radiological features and rarity of this tumor extending into posterior fossa. PMID:25250083

Kharosekar, Hrushikesh U.; Jasmit, S.; Velho, V.; Palande, D. A.

2014-01-01

103

Gd Transition Probabilities and Abundances

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 first using a high performance Fourier transform spectrometer. This improved data set has been used to determine a new solar photospheric Gd abundance, log epsilon = 1.11 +/- 0.03. Revised Gd abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, and HD 115444. The resulting Gd/Eu abundance ratios are in very good agreement with the solar-system r-process ratio. We have employed the increasingly accurate stellar abundance determinations, resulting in large part from the more precise laboratory atomic data, to predict directly the Solar System r-process elemental abundances for Gd, Sm, Ho and Nd. Our analysis of the stellar data suggests slightly higher recommended values for the r-process contribution and total Solar System values, consistent with the photospheric determinations, for the elements for Gd, Sm, and Ho.

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

2006-09-18

104

Estimating the Probability of Negative Events

ERIC Educational Resources Information Center

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…

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

2009-01-01

105

Posterior vertebral injury; is this a burst fracture or a flexion-distraction injury?

In thoracolumbar spinal fractures with posterior column injury for applying proper management, it is important to distinguish a flexion-distraction injury (FDI) from a three column burst fracture (BF) as in clinical examination, both may have a similar significant tenderness on direct spinal palpation. Careful attention to the comprehensive clinical examination and detailed imaging features are essential in making an accurate diagnosis and thus appropriate treatment. PMID:25207330

Omidi-Kashani, Farzad

2014-06-01

106

Posterior Vertebral Injury; Is This a Burst Fracture or a Flexion-Distraction Injury?

In thoracolumbar spinal fractures with posterior column injury for applying proper management, it is important to distinguish a flexion-distraction injury (FDI) from a three column burst fracture (BF) as in clinical examination, both may have a similar significant tenderness on direct spinal palpation. Careful attention to the comprehensive clinical examination and detailed imaging features are essential in making an accurate diagnosis and thus appropriate treatment. PMID:25207330

Omidi-Kashani, Farzad

2014-01-01

107

Posterior Density Estimation for a Class of On-line Quality Control Models

NASA Astrophysics Data System (ADS)

On-line quality control during production calls for a periodical monitoring of the produced items according to some prescribed strategy. It is reasonable to assume the existence of internal non-observable variables so that the carried out monitoring is only partially reliable. Under the setting of a Hidden Markov Model (HMM), posterior density estimates are obtained via particle filter type algorithms. Making use of kernel density methods the stable regime densities are approximated and false-alarm probabilities are estimated.

Dorea, Chang C. Y.; Santos, Walter B.

2011-11-01

108

Summary The debate over the relative merits of substituting or retaining the posterior cruciate ligament in total knee arthroplasty is still ongoing. This article discusses the differences between the two procedures, considering the biomechanics and the surgical techniques involved.

D’Anchise, Roberto; Andreata, Mauro; Balbino, Cristiana; Manta, Nicola

2013-01-01

109

BACKGROUND: Identification of RNA homologs within genomic stretches is difficult when pairwise sequence identity is low or unalignable flanking residues are present. In both cases structure-sequence or profile\\/family-sequence alignment programs become difficult to apply because of unreliable RNA structures or family alignments. As such, local sequence-sequence alignment programs are frequently used instead. We have recently demonstrated that maximal expected accuracy

Usman Roshan; Satish Chikkagoudar; Dennis R. Livesay

2008-01-01

110

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

. Polymerase chain reaction (PCR) assays were performed on DNA from three breed groups of unrelated horses (E. caballus) and from an Arabian half-sib family. PCR amplification was also attempted for homologous loci in Grant's zebra, E. burchelli granti. PCR...

Chastain, Pepper Alise

2012-06-07

111

Applied Probability Trust (6 June 2008) ASYMPTOTICS OF POSTERIORS FOR BINARY BRANCHING

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, UniversitĂ© de

112

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

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, UniversitĂ© de

113

Purpose. To report the results of the posterior pole sparing laser photocoagulation combined with intravitreal bevacizumab injection (IVB) in retinopathy of prematurity (ROP). Methods. A retrospective chart review of premature babies with ROP, all of whom received laser photocoagulation with IVB. Eleven eyes of 6 infants with advanced zone I ROP underwent laser ablation sparing posterior pole with concurrent IVB. The results were compared with those of full-laser treatment combined with IVB to 8 eyes of 5 infants with advanced ROP without involvement of the posterior pole. Results. The posterior pole sparing laser with IVB was performed with zone I, stage 3+ ROP at the mean postmenstrual age of 36 weeks and 5 days. The plus sign decreased significantly at postoperative day 1, the neovascular proliferation regressed by postoperative week 1, and the normal vascularization started at postoperative day 32 on the average. Two months after treatment, vascularization of the spared avascular area was completed. There was no macular dragging, tractional retinal detachment, foveal destruction by laser scars, or any other adverse event. No significant anatomical differences were identified from those of full-laser ablation combined with IVB. Conclusions. Posterior pole sparing laser with IVB can give favorable results without destruction of posterior pole retina. PMID:25614828

Kim, Rebecca; Kim, Yu Cheol

2014-01-01

114

NSDL National Science Digital Library

Given the population incidence of a certain disease, and the conditional probabilities of positive and negative test results, what are the probabilities for a particular test result of a true positive, true negative, false positive, and false negative? Adaptable to other kinds of conditional situations. Although this page is adaptable to a variety of backward probability situations, its exemplary case is the one in which one is seeking to make sense of the result of a medical test.

Lowry, Richard

2009-10-06

115

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

2014-06-01

116

Choroid plexus papilloma in the posterior fossa.

Choroid plexus papillomas in the posterior fossa can present with different clinical signs and symptoms. The tumors in the patients we discuss in this article originated from different sites of the choroid plexus. One patient, who had a fourth ventricle papilloma, experienced unsteady gait and episodes of dizziness over many years. The tumor was cystic an calcified, and adherent to the brain-stem. The second patient had only signs of increased intracranial pressure. A soft tumor was located in the cerebellomedullary cistern. The third patient, with a papilloma in the cerebellopontine angle, complained of hearing loss. This tumor was firmly adherent to the dura mater and looked exactly like a meningioma. The appearance on computed tomography scan, the macroscopic aspect, and the vascular supply of a papilloma in the posterior fossa can vary considerably. PMID:3496674

van Swieten, J C; Thomeer, R T; Vielvoye, G J; Bots, G T

1987-08-01

117

Pseudoexfoliation material on posterior chamber intraocular lenses

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; Falcăo-Reis, Fernando; Melo, António B

2014-01-01

118

Material Properties of the Posterior Human Sclera?

To characterize the material properties of posterior and peripapillary sclera from human donors, and to investigate the macro- and micro-scale strains as potential control mechanisms governing mechanical homeostasis. Posterior scleral shells from 9 human donors aged 57–90 years were subjected to IOP elevations from 5 to 45 mmHg and the resulting full-field displacements were recorded using laser speckle interferometry. Eye-specific finite element models were generated based on experimentally measured scleral shell surface geometry and thickness. Inverse numerical analyses were performed to identify material parameters for each eye by matching experimental deformation measurements to model predictions using a microstructure-based constitutive formulation that incorporates the crimp response and anisotropic architecture of scleral collagen fibrils. The material property fitting produced models that fit both the overall and local deformation responses of posterior scleral shells very well. The nonlinear stiffening of the sclera with increasing IOP was well reproduced by the uncrimping of scleral collagen fibrils, and a circumferentially-aligned ring of collagen fibrils around the scleral canal was predicted in all eyes. Macroscopic in-plane strains were significantly higher in peripapillary region then in the mid-periphery. In contrast, the meso- and micro-scale strains at the collagen network and collagen fibril level were not significantly different between regions. The elastic response of the posterior human sclera can be characterized by the anisotropic architecture and crimp response of scleral collagen fibrils. The similar collagen fibril strains in the peripapillary and mid-peripheral regions support the notion that the scleral collagen architecture including the circumpapillary ring of collagen fibrils evolved to establish optimal load bearing conditions at the collagen fibril level. PMID:23684352

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

2013-01-01

119

Material properties of the posterior human sclera.

To characterize the material properties of posterior and peripapillary sclera from human donors, and to investigate the macro- and micro-scale strains as potential control mechanisms governing mechanical homeostasis. Posterior scleral shells from 9 human donors aged 57-90 years were subjected to IOP elevations from 5 to 45mmHg and the resulting full-field displacements were recorded using laser speckle interferometry. Eye-specific finite element models were generated based on experimentally measured scleral shell surface geometry and thickness. Inverse numerical analyses were performed to identify material parameters for each eye by matching experimental deformation measurements to model predictions using a microstructure-based constitutive formulation that incorporates the crimp response and anisotropic architecture of scleral collagen fibrils. The material property fitting produced models that fit both the overall and local deformation responses of posterior scleral shells very well. The nonlinear stiffening of the sclera with increasing IOP was well reproduced by the uncrimping of scleral collagen fibrils, and a circumferentially aligned ring of collagen fibrils around the scleral canal was predicted in all eyes. Macroscopic in-plane strains were significantly higher in peripapillary region then in the mid-periphery. In contrast, the meso- and micro-scale strains at the collagen network and collagen fibril level were not significantly different between regions. The elastic response of the posterior human sclera can be characterized by the anisotropic architecture and crimp response of scleral collagen fibrils. The similar collagen fibril strains in the peripapillary and mid-peripheral regions support the notion that the scleral collagen architecture including the circumpapillary ring of collagen fibrils evolved to establish optimal load bearing conditions at the collagen fibril level. PMID:23684352

Grytz, Rafael; Fazio, Massimo A; Girard, Michaël J A; Libertiaux, Vincent; Bruno, Luigi; Gardiner, Stuart; Girkin, Christopher A; Downs, J Crawford

2014-01-01

120

NASA Astrophysics Data System (ADS)

With the development of intelligent transport system, advanced information feedback strategies have been developed to reduce traffic congestion and enhance the capacity. However, previous strategies provide accurate information to travelers and our simulation results show that accurate information brings negative effects, especially in delay case. Because travelers prefer to the best condition route with accurate information, and delayed information cannot reflect current traffic condition but past. Then travelers make wrong routing decisions, causing the decrease of the capacity and the increase of oscillations and the system deviating from the equilibrium. To avoid the negative effect, bounded rationality is taken into account by introducing a boundedly rational threshold BR. When difference between two routes is less than the BR, routes have equal probability to be chosen. The bounded rationality is helpful to improve the efficiency in terms of capacity, oscillation and the gap deviating from the system equilibrium.

Zhao, Xiao-mei; Xie, Dong-fan; Li, Qi

2015-02-01

121

Indocyanine green angiography in posterior uveitis

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

2013-01-01

122

Posterior mini-incision hamstring harvest.

Many orthopedists looking for alternatives to autograft bone-patellar-tendon-bone grafts are uncertain of their ability to harvest a hamstring graft of adequate length. They may use an allograft instead for this reason despite recent reports of high failure rates. This article presents step-by-step instructions for a posterior mini-incision hamstring harvest that offers a safe and simple method of reliably harvesting sufficient hamstring for 4 or 6 strand repair, while using tiny incisions for excellent cosmesis and minimal pain. Access from the posterior mini-incision allows easy identification and differentiation of the semitendinosus and gracilis (Gr) tendons, as well as precise placement of the anterior mini-incision for tibial tunnel drilling and fixation. Most importantly sectioning of the intertendinous cross-connections is performed under easy direct vision posteriorly, instead of at a distance from the typical anterior incision under retractors. This prevents the tendons from being cut too short by the tendon stripper and is particularly useful in large patients. In addition to the surgical procedure, details on the required equipment are presented. PMID:20160624

Prodromos, Chadwick C

2010-03-01

123

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

2009-10-30

124

Probability Forecasting in Meteorology

Efforts to quantify the uncertainty in weather forecasts began more than 75 years ago, and many studies and experiments involving objective and subjective probability forecasting have been conducted in meteorology in the intervening period. Moreover, the U.S. National Weather Service (NWS) initiated a nationwide program in 1965 in which precipitation probability forecasts were formulated on an operational basis and routinely

Allan H. Murphy; Robert L. Winkler

1984-01-01

125

Interactive Applet: Probability

NSDL National Science Digital Library

This applet, created by McGraw-Hill Higher Education, is designed to help students visualize how observed probability approaches true probability as sample size increases by simulating rolling dice. It accompanies "Statistical Techniques in Business and Economics," but does not require use of the text. This is a fun lesson for students wanting to delve deeper into the world of statistics.

2011-10-03

126

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.

2008-12-19

127

Creativity, probability and uncertainty

Keynesian concepts of probability and uncertainty emphasize the basis of knowledge available to economic decision makers. Conditions of uncertainty, which involve missing evidence or doubtful arguments, are distinguished from probable risk. Beyond this, on the basis of the claim that the future is yet to be created, some authors argue for further distinctions among different kinds of uncertainty. The paper

Matthew C. Wilson

2009-01-01

128

Posterior semicircular canal dehiscence following endolymphatic sac surgery.

Posterior semicircular canal dehiscence is a rare otologic entity that presents with third window signs and symptoms. Petrous apex cholesteatoma, fibrous dysplasia, high riding jugular bulb, and eosinophilic granuloma have been reported to be associated with posterior semicircular canal dehiscence. Here we report a case of development of posterior semicircular canal dehiscence following an endolymphatic sac surgery for the first time. PMID:22689472

Kiumehr, Saman; Mahboubi, Hossein; Djalilian, Hamid R

2012-09-01

129

Bayesian Posterior Comprehension via Message from Monte Carlo

Bayesian Posterior Comprehension via Message from Monte Carlo Leigh J. Fitzgibbon, David L. Dowe Markov Chain Monte Carlo methods. The Message from Monte Carlo methodology is illustrated for binary Length, MML, MCMC, RJMCMC, Message from Monte Carlo, MMC, posterior summary, epitome, Bayesian Posterior

Allison, Lloyd

130

Posterior Semicircular Canal Dehiscence Following Endolymphatic Sac Surgery

Posterior semicircular canal dehiscence is a rare otologic entity which presents with third window signs and symptoms. Petrous apex cholesteatoma, fibrous dysplasia, high riding jugular bulb, and eosinophilic granuloma have been reported to be associated with posterior semicircular canal dehiscence. Here we report a case of development of posterior semicircular canal dehiscence following an endolymaphatic sac surgery for the first time. PMID:22689472

Kiumehr, Saman; Mahboubi, Hossein; Djalilian, Hamid R.

2012-01-01

131

Controversies in posterior composite resin restorations.

The use of posterior composites is riddled with so many controversies that the puzzled practitioner must step warily among them. This modality is a minefield, where one careless movement can bring disaster. All composite restorations are subject to three big destructive forces--moisture, polymerization shrinkage, and clinical wear--forces that can eventually produce both microleakage and deterioration of the silane coupling agent linking filler particles to resin matrix. Despite the extreme technique sensitivity of posterior composite resins, knowledge of resin technology, sound operative dentistry principles and foresight in case selection can be effective in producing durable cosmetic restorations. Posterior composite resin restorations bonded to enamel and dentin reputedly strengthen teeth in both conventional and adhesive types of preparations provided polymerization shrinkage can be controlled. It is imperative that a knowledge of occlusal contacts be used to influence cavity outline, confining the trauma or occlusal forces away from the tooth-resin interface and helping to minimize occlusal wear. With the increased use of posterior resins, the trend in cavity preparations should break away from the traditional Black preparation toward the adhesive type preparation. If the Black Class II preparation is used, it is suggested that bevels be confined to the facial and lingual margins of the proximal box. Prewedging helps to maintain a conservative Class II preparation. Shade selection must be made prior to rubber dam isolation for greater accuracy and to help prevent postinsertion discoloration. The enamel should be pumiced to present a clean substrate for acid etching. The smear layer should be removed. The type of pulp protection applied before acid etching is dependent on the material used. After etching, the enamel should be washed with a 1 per cent potassium chloride solution. It is a more universally chemically stable solution than additive-laden local water supplies. The potassium chloride solution lowers the electrostatic forces on the enamel that would interfere with the flow of enamel bonding agents. Furthermore, tests have shown that the use of potassium chloride washes increase the strength of the enamel body by 40 per cent. Because of the depth of most posterior cavities, an incremental filling technique must be used to ensure a thorough polymerization of the resin and to forestall a massive polymerization shrinkage. When finished and contoured, the margins of the restoration should be re-etched, washed, and dried and then covered with an application of unfilled resin to discourage microleakage. Traditional operative dentistry technique must become flexible enough to meet the new demands of resin technology.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2403943

Wilson, E G; Mandradjieff, M; Brindock, T

1990-01-01

132

Acetabular fractures can be classified into 5 simple and 5 associated fracture patterns. A significant amount of variation and complexity exists in these fractures patterns. Fractures of the posterior wall are the most common acetabular fractures. Comminution of the quadrilateral plate adds to fracture instability, and more rigid and stable internal fixation is mandatory. The goal of this study was to assess the results of reconstruction of comminuted posterior wall fractures of the acetabulum associated with quadrilateral plate fractures using the tension band technique. Twelve patients (9 men and 3 women) were included in the study. Mean patient age was 38.6 years (range, 24-47 years). Minimum follow-up was more than 2 years postoperatively. Reconstruction of the fracture included anatomic reduction of the fracture and fixation with a buttress plate for the posterior column and a prebent one-third tubular plate for the quadrilateral plate fracture. Clinical results were excellent in 58% of patients and good in 17% of patients. Radiologic results were excellent in 50% of patients and good in 17% of patients. Radiologically, based on the fracture gap postoperatively, 8 (66%) patients showed anatomic reduction, 2 (17%) showed good reduction, and 2 (17%) showed poor reduction. The study confirms that this method of reconstruction facilitates accurate and firm reduction of displaced posterior wall fractures of the acetabulum. PMID:23823039

Aly, Tarek A; Hamed, Hany

2013-07-01

133

NSDL National Science Digital Library

This three lesson unit (15-page pdf) presents activities that guide students to understand the probability terms "certain" and "impossible". In each of the first two lessons students work as a class to conduct an experiment, complete sentences about the contents of a mystery bag, write probability statements, and express probability as common fractions. In the final lesson the class hears a story that contains both certain and impossible events. Students discuss which events are certain and impossible, and then construct a class book illustrating these concepts.

2009-01-01

134

NSDL National Science Digital Library

These pages present, in terms of a fictional story based on true events, the problem that inspired the development of mathematical probability in Renaissance Europe by French mathematicians Pierre de Fermat and Blaise Pascal. Two equally skilled players are interrupted while playing a game of chance for a certain amount of money. Given the score of the game at that point, how should the stakes be divided? Outlined here is, first, the particular solution and then the general solution based on a central concept of probability, equally probable outcomes.

Forum, The M.

1998-01-01

135

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

1993-11-01

136

Understanding Experimental Probability

NSDL National Science Digital Library

Experiment with experimental probability using a fixed size section spinner, a variable section spinner, 2 regular 6-sided number cubes or design your own number cubes. Appropriate for elementary grades.

The Shodor Education Foundation, Inc.

2007-12-12

137

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.

1981-01-01

138

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.

2012-08-03

139

Dynamical simulations of probabilities

It has been demonstrated that classical probabilities, and in particular, the probabilistic Turing machine, can be simulated by combining chaos and non-Lipschitz dynamics, without utilization of any man-made devices (such as random number generators). Self-organizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed. Special attention was focused upon coupled stochastic processes, defined

Michail Zak

1997-01-01

140

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.

2010-01-01

141

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.

2014-09-18

142

This second portion of a two-part review illustrates examples of posterior fossa disorders detectable on prenatal ultrasound and MRI, with postnatal or pathology correlation where available. These disorders are discussed in the context of an anatomic classification scheme described in Part 1 of this posterior fossa anomaly review. Assessment of the size and formation of the cerebellar hemispheres and vermis is critical. Diagnoses discussed here include arachnoid cyst, Blake's pouch cyst, Dandy-Walker malformation, vermian agenesis, Joubert syndrome, rhombencephalosynapsis, Chiari II malformation, ischemia, and tumors. PMID:25457569

Chapman, Teresa; Mahalingam, Sowmya; Ishak, Gisele E; Nixon, Jason N; Siebert, Joseph; Dighe, Manjiri K

2014-10-22

143

Trigeminal neuralgia secondary to posterior fossa tumor

Trigeminal neuralgia (TN) is by no means an uncommon entity presenting as typical or atypical pain syndrome with a standard treatment protocol consisting of medical and surgical therapies. The diagnosis of TN is mainly dependent on the characteristics of symptoms conveyed by the patient and the clinical presentation. Careful history taking, proper interpretation of the signs and symptoms and cranial nerve assessment are necessary for proper diagnosis. Here, we report a case of TN, treated for dental problems and then for neuralgia with only short-term relief. Subsequently, the patient underwent neuroimaging and was found to be having an uncommon space-occupying lesion in the posterior cranial fossa. PMID:22442556

Agrawal, Mamta; Agrawal, Vikrant; Agrawal, Rajiv; Pramod, D.S.R.

2010-01-01

144

Complications of posterior cruciate ligament surgery.

In addition to standard risks associated with all orthopedic surgical procedures, posterior cruciate ligament (PCL) reconstruction poses some relatively unique potential complications. These complications arise from a combination of several factors: the relative infrequency of PCL injuries, the lack of knowledge and experience in treating them, the proximity of neurovascular structures to the PCL, and the technically demanding nature of reconstructive procedures. This article discusses the anatomy, pathogenesis, and prevention of intraoperative and postoperative complications of PCL surgery including neurovascular injury, osteonecrosis, fracture, motion loss, and persistent laxity. PMID:21079507

Zawodny, Sarah R; Miller, Mark D

2010-12-01

145

Partial posterior hyaloidectomy for macular disorders

Purpose To evaluate the effect of partial posterior hyaloidectomy (PPH) in preventing iatrogenic retinal breaks related to the induction of a posterior vitreous detachment (IPVD) Methods Fifty-nine patients who necessitated IPVD for an epiretinal membrane or macular hole were included in this prospective, interventional case series. Extensive removal of vitreous gel, close to the retina, was conducted before IPVD under 23?G (gauge)-vitrectomy system. The PPH involved the limited extent of IPVD and limited removal of the outermost vitreous cortex to an area slightly beyond the margin of the temporal major vascular arcade. The incidence of retinal breaks related to the surgery was compared with 57 eyes that had undergone conventional 23-G total vitrectomy accompanied by extensive IPVD using ?2-test. Results Patients were followed-up for a mean of 14.3 months (6–30 months) after the surgery. The incidence of peripheral retinal breaks after the PPH was 3.4% (2/59 eyes), which was significantly lower than that in the eyes that underwent conventional 23?G vitrectomy (15.8%, 9/57 eyes, P=0.023) for the same disorders that required an IPVD. No patient complained of postoperative floaters, postoperatively. Conclusions PPH would be an efficient procedure to prevent iatrogenic peripheral retinal breaks related to an IPVD. PMID:23743531

Kim, J H; Kang, S W; Kim, Y T; Kim, S J; Chung, S E

2013-01-01

146

Sampling Networks from Their Posterior Predictive Distribution

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

2014-01-01

147

Posterior consistency in conditional distribution estimation

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.

2014-01-01

148

Posterior Interosseous Nerve Syndrome from Thermal Injury

Background. Due to anatomical proximity to bone, the radial nerve is the most frequently injured major nerve of the upper extremity, frequently secondary to fractures (Li et al. (2013)). We describe an incidence when a branch of the radial nerve is injured as a result of a thermal injury. Observation. Radial nerve injury can occur anywhere along the anatomical course with varied etiologies, but commonly related to trauma. The most frequent site is in the proximal forearm involving the posterior interosseous branch. However, problems can occur at the junction of the middle and proximal thirds of the humerus and wrist radially. When the radial nerve is injured by a burn, a new rehabilitation dynamic arises. Not only does one agonize about the return of nerve function but also fret about the skin grafts that replaced the devitalized tissue housing that compartment. Discussion. Although posterior interosseous nerve syndrome has been described in the context of many different etiologies, it has not previously been discussed in relation to burn injuries. In this case, not only did the patient's rehabilitation involve aggressive therapy for return of sensation and function of the arm, but also prevention of contracture normally seen in replacement of full thickness burns. PMID:24707432

Singh, Vijay A.; Michael, Rami E.; Dinh, Duy-Bao P.; Bloom, Scott; Cooper, Michael

2014-01-01

149

Probability Theory as Logic: Data Assimilation for Multiple Source Reconstruction

NASA Astrophysics Data System (ADS)

Probability theory as logic (or Bayesian probability theory) is a rational inferential methodology that provides a natural and logically consistent framework for source reconstruction. This methodology fully utilizes the information provided by a limited number of noisy concentration data obtained from a network of sensors and combines it in a consistent manner with the available prior knowledge (mathematical representation of relevant physical laws), hence providing a rigorous basis for the assimilation of this data into models of atmospheric dispersion for the purpose of contaminant source reconstruction. This paper addresses the application of this framework to the reconstruction of contaminant source distributions consisting of an unknown number of localized sources, using concentration measurements obtained from a sensor array. To this purpose, Bayesian probability theory is used to formulate the full joint posterior probability density function for the parameters of the unknown source distribution. A simulated annealing algorithm, applied in conjunction with a reversible-jump Markov chain Monte Carlo technique, is used to draw random samples of source distribution models from the posterior probability density function. The methodology is validated against a real (full-scale) atmospheric dispersion experiment involving a multiple point source release.

Yee, Eugene

2012-03-01

150

NSDL National Science Digital Library

With many computer users developing their own Web sites, some of them may be interested in monitoring how search engines may be ranking their site. This latest edition of Accurate Monitor may prove useful, as it allows individuals to find the position of their Web site in search engines like Altavista and Google. Additionally, Accurate Monitor can generate advanced statistics and monitor plugins, along with providing a flexible interface system. This version of Accurate Monitor is compatible with all systems running Windows 95 and higher.

2003-01-01

151

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.

152

Background The posterior sclera likely plays an important role in the development of glaucoma and accurate characterization of its mechanical properties is needed to understand its impact on the more delicate optic nerve head – the primary site of damage in the disease. Method of Approach The posterior scleral shells from both eyes of one rhesus monkey were individually mounted on a custom-built pressurization apparatus. Intraocular pressure was incrementally increased from 5 to 45 mm Hg, and the 3-D displacements were measured using electronic speckle pattern interferometry. Finite element meshes of each posterior scleral shell were reconstructed from data generated by a 3D digitizer arm (shape) and a 20 MHz ultrasound transducer (thickness). An anisotropic hyperelastic constitutive model described in a companion paper [1], which includes stretch-induced stiffening and multi-directional alignment of the collagen fibers, was applied to each reconstructed mesh. Surface node displacements of each model were fitted to the experimental displacements using an inverse finite element method, which estimated a unique set of thirteen model parameters. Results The predictions of the proposed constitutive model matched the 3-D experimental displacements well. In both eyes, the tangent modulus increased dramatically with IOP, which indicates that the sclera is mechanically nonlinear. The sclera adjacent to the optic nerve head, known as the peripapillary sclera, was thickest and exhibited the lowest tangent modulus, which might have contributed to the uniform distribution of the structural stiffness for each entire scleral shell. Conclusions Posterior scleral deformation following acute IOP elevations appears to be nonlinear and governed by the underlying scleral collagen microstructure as predicted by finite element modeling. The method is currently being used to characterize posterior scleral mechanics in normal (young and old), early and moderately glaucomatous monkey eyes. PMID:19388782

Girard, Michaël J. A.; Downs, J. Crawford; Bottlang, Michael; Burgoyne, Claude F.; Suh, J-K. Francis

2009-01-01

153

NSDL National Science Digital Library

Education in a free society must prepare citizens to make informed choices in all areas of their lives. They must be able to grasp the information being presented, analyze it, and make reasoned decisions. To accomplish these goals, students learn to collect, organize, and display relevant data to answer questions that can be addressed with data; use appropriate statistical methods and predictions that are based on data; develop and evaluate inferences and predictions that are based on data; and apply basic concepts of probability. Probability is the study of chance and the possibility that an event will occur.

K-12 Outreach,

154

Isolated posterior femoral cutaneous neuropathy following intragluteal injection.

Isolated posterior femoral cutaneous nerve lesions are rarely encountered. Electrophysiological documentation has only been made in a few cases. In this study we evaluated a 22-year-old woman with sensory loss and pain in the lower buttock and posterior thigh after left gluteal intramuscular injection. We assessed the posterior femoral cutaneous nerve using an accepted conduction technique. The results showed a normal response on the asymptomatic side, but no response on the symptomatic side. PMID:19623639

Kim, Jee-Eun; Kang, Ji-Hoon; Choi, Jay Chol; Lee, Jung Seok; Kang, Sa-Yoon

2009-11-01

155

Late posterior failure after mitral valve repair in degenerative disease

Objectives: Little is known regarding the mechanisms, the feasibility and the long-term results of re-repair in 'posterior failure' of a previous mitral valve repair performed for severe degenerative mitral regurgitation. We report our 16-year experience in redo surgery for late posterior failureofmitralvalverepairindegenerativedisease.Methods:From1991to2004,13consecutivepatients(10males;medianage:65years)were reoperated for late posterior failure of mitral valve repair. All patients had grade 3+ mitral regurgitation. Repair was

Rachid Zegdi; Ghassan Sleilaty; Ziad Khabbaz; Milena Noghin; Christian Latremouille; Alain Carpentier; Alain Deloche; Jean-Noel Fabiani

156

Progression in Primary Probability

NSDL National Science Digital Library

In this brief article from NRICH, the author describes the progression of probability from informal in early elementary grades to more formal experiences in upper elementary grades. Throughout the article the author suggests activities and problems presented on the NRICH website and linked through the article.

Mcclure, Lynne

2010-11-01

157

Univariate Probability Distributions

ERIC Educational Resources Information Center

We describe a web-based interactive graphic that can be used as a resource in introductory classes in mathematical statistics. This interactive graphic presents 76 common univariate distributions and gives details on (a) various features of the distribution such as the functional form of the probability density function and cumulative distribution…

Leemis, Lawrence M.; Luckett, Daniel J.; Powell, Austin G.; Vermeer, Peter E.

2012-01-01

158

The propositional logic is generalized on the real numbers field. The logical analog of the Bernoulli independent tests scheme is constructed. The variant of the nonstandard analysis is adopted for the definition of the logical function, which has all properties of the classical probability function. The logical analog of the Large Number Law is deduced from properties of this function.

G. A. Quznetsov

2010-09-14

159

Approximating Integrals Using Probability

ERIC Educational Resources Information Center

As part of a discussion on Monte Carlo methods, which outlines how to use probability expectations to approximate the value of a definite integral. The purpose of this paper is to elaborate on this technique and then to show several examples using visual basic as a programming tool. It is an interesting method because it combines two branches of…

Maruszewski, Richard F., Jr.; Caudle, Kyle A.

2005-01-01

160

NSDL National Science Digital Library

This lesson is designed to develop students' ability to create tree diagrams and figure probabilities of events based on those diagrams. This lesson provides links to discussions and activities related to tree diagrams as well as suggested ways to work them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2011-01-20

161

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.

2009-01-01

162

course [electronic resource]. New York, NY: Springer Science+Business Media, Inc. Klenke, A. (2008Gupta, A. (2011). Probability for statistics and machine learning [electronic resource]: Fundamentals and advanced topics (1st ed.). New York, NY: Springer Science+Business Media, LLC. 1 All references

Lin, Xiaodong

163

NSDL National Science Digital Library

This resource consists of a Java applet and Expository text. The applet simulates the probability plot that compares the empirical quantiles of a sample from a sampling distribution to the distribution quantiles of a test distribution. The sampling distribution, test distribution, and sample size can be specified.

Siegrist, Kyle

164

Stage IV posterior tibial tendon rupture.

Adult acquired flatfoot deformity progresses through well defined stages as set out by Johnson and Strom. Myerson modified this classification system with the addition of a fourth, more advanced stage of the disease. This stage describes the involvement of the tibiotalar joint in addition to the hindfoot malalignment seen in stages II and III. This most advanced stage is comprised of a hindfoot valgus deformity, resulting from degeneration of the posterior tibial tendon, with associated valgus tilting of the talus within the mortise. The deformity at the tibiotalar joint may or may not be rigid. Although rigid deformities are still best treated with fusions of the ankle and hindfoot, supple tibiotalar deformity may be treated with joint sparing procedures involving reconstructive procedures of the foot and deltoid ligaments. PMID:17561206

Bluman, Eric M; Myerson, Mark S

2007-06-01

165

Ectomesenchymal chondromyxoid tumour of the posterior tongue.

Ectomesenchymal chondromyxoid tumor (ECMT) is a rare benign neoplasm arising in the tongue. With only 45 cases reported in the literature, there are several unique features defining this lesion. Firstly, almost all patients present with an asymptomatic slow growing mass on the anterior dorsum of the tongue. At the microscopic level, it is recognizable as a well-circumscribed unencapsulated proliferation of uniform round to fusiform cells embedded in a chondromyxoid matrix. Lastly, the immunohistochemistry profile is characterised by positivity for glial fibrillary acidic protein and frequent positivity for S-100 and cytokeratins. We report a case of a mass located on the posterior dorsum of the tongue and meeting the aforementioned morphological and immunohistochemical criteria of ECMT. PMID:24288100

Cardin, Marie-Josée; Fiset, Pierre Olivier; Zeitouni, Anthony G; Caglar, Derin

2014-09-01

166

[Epidural hematomas in the posterior cranial fossa].

In the course of twenty years 92 patients with intracranial epidural haematomas (EH) were operated. In five these patients, i.e. 5.4%, the EH was in the posterior cranial fossa (EHPF). Focal symptoms of compression of the cerebellum and the lower cranial nerves developed only in subacute EHPF. In acute EHPF it was masked by manifestations of an affection of the brain stem. Direct evidence of EHPF was produced by AG. The best diagnostic method is computed tomography. Attention to EHPF can be however, drawn also clinical sings of injury of the bask of the skull or the finding of a fracture of the occipital bone on an X-ray picture of the skull. Evacuation of the EHPF provides favourable perspectives of a normal future life even on patients who are in a poor condition incl. signs of and impaired respiration. PMID:2237649

Steno, J; Fröhlich, J; Bízik, I

1990-06-01

167

Posterior Cruciate Ligament: Focus on Conflicting Issues

There is little consensus on how to optimally reconstruct the posterior cruciate ligament (PCL) and the natural history of injured PCL is also unclear. The graft material (autograft vs. allograft), the type of tibial fixation (tibial inlay vs. transtibial tunnel), the femoral tunnel position within the femoral footprint (isometric, central, or eccentric), and the number of bundles in the reconstruction (1 bundle vs. 2 bundles) are among the many decisions that a surgeon must make in a PCL reconstruction. In addition, there is a paucity of information on rehabilitation after reconstruction of the PCL and posterolateral structures. This article focused on the conflicting issues regarding the PCL, and the scientific rationales behind some critical points are discussed. PMID:24340144

Lee, Yong Seuk

2013-01-01

168

Allocentric spatial neglect with posterior cortical atrophy.

Patients with posterior cortical atrophy (PCA) have been reported to have neglect in the egocentric/ body-centered reference frame. This report describes a woman with PCA who had a right-sided stimulus-based form of allocentric visual neglect on cancellation, reading, and drawing tests. Her brain imaging revealed left parietal atrophy. The pathophysiology of this disorder may be related to an impairment of the ventral "what" stream's ability to interact with the dorsal "where" stream that mediates the allocation of spatial attention, or a deficit in the systems that allocate contralateral focal attention. Further research is needed to better understand the mechanisms of this disorder and to optimally treat it. PMID:24679168

Zilli, Eduardo M; Heilman, Kenneth M

2015-04-01

169

Hf Transition Probabilities and Abundances

Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf/La) = -0.13 +/- 0.02 (sigma = 0.06) and log epsilon (Hf/Eu) = +0.04 +/- 0.02 (sigma = 0.06). The observed average stellar abundance ratio of Hf/Eu and La/Eu is larger than previous estimates of the solar system r-process-only value, suggesting a somewhat larger contribution from the r-process to the production of Hf and La. The newly determined Hf values could be employed as part of the chronometer pair, Th/Hf, to determine radioactive stellar ages.

J. E. Lawler; E. A. Den Hartog; Z. E. Labby; C. Sneden; J. J. Cowan; I. I. Ivans

2006-11-01

170

L’artroprotesi totale di ginocchio si č oramai dimostrata un presidio efficace nel ridurre l’entitŕ del dolore ed incrementare\\u000a le capacitŕ funzionali. Dati ottenuti da studi eseguiti sia su artroprotesi postero-stabilizzate (PS) che su quelle a conservazione\\u000a del crociato posteriore (PCR) hanno messo in evidenza risultati rilevanti anche a lungo termine. Ancora oggi esiste, tuttavia,\\u000a notevole controversia su quale sia il

G. Cerulli; A. Caraffa; P. Antinolfi; G. Zamarra

171

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

2014-06-01

172

Probability in Quantum Mechanics

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

173

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

2009-01-13

174

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

A. B. GLENN

1983-01-01

175

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.

2008-01-01

176

Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)

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

2013-01-01

177

LOCAL SENSITIVITY, FUNCTIONAL DERIVATIVES AND NONLINEAR POSTERIOR QUANTITIES

LOCAL SENSITIVITY, FUNCTIONAL DERIVATIVES AND NONLINEAR POSTERIOR QUANTITIES by Sanjib Basu 1 University of Arkansas, Fayetteville, AR 72701 February, 1994 Abstract The local sensitivity of a posterior quantities are established under these definitions. Local sensitivity is measured by maxiÂ mizing

Basu, Sanjib

178

Investigation of occiput posterior delivery by intrapartum sonography

Objective To investigate if occiput posterior delivery is the consequence of persistence of an initial occiput posterior position or malrotation from an initial occiput anterior or transverse position. Methods This was a cross-sectional study involving transabdominal sonography to determine fetal occipital position in 918 singleton pregnancies with cephalic presentation in active labor at 37-42 weeks of gestation. The relationship between

S. Akmal; E. Tsoi; R. Howard; E. Osei; K. H. Nicolaides

2004-01-01

179

Accurate Replication in Genetic Programming

Abstract One characteristic tendency of genetic program - ming is the production of considerably larger trees than expected It has been suggested that this is related to the ability of individuals to replicate ac - curately In this paper we present theoretical anal - ysis which shows that, for certain specific cases, the pressure for accurate replication induces an increase

Nicholas Freitag Mcphee; Justin Darwin Miller

1995-01-01

180

Equal prior probabilities: can one do any better?

This paper discusses recommendations concerning the use of prior probabilities that underlie recent, but in no way novel, proposals of presenting scientific evidence in terms of posterior probabilities, in the context sometimes referred to as the 'full Bayes' approach'. A chief issue of this procedure is a proposal that--given the unavailability of case-specific circumstantial information--scientists should consider the prior probabilities of the propositions under which scientific evidence is evaluated as equal. The discussion presented here draws the reader's attention to the fact that the philosophical foundations of such a recommendation (in particular, attempted justifications through the Principle of Maximum Entropy (PME)) are far more controversial than what is actually admitted by the advocates for their use in the theory and practice of forensic science. Invoking only basic assumptions and the mathematical rules of probability calculus, the authors of this paper propose an argument that shows that there can be other more feasible and defensible strategies for eliciting reasonable prior probabilities. It is solely demanded that the reasoner is willing to make up his mind seriously on certain standard issues of fairly general criminal cases, such as evidential relevance or the probability of a suspect's guilt. However, because these issues intimately pertain to the responsibility of the trier of the fact, it is argued here that scientists' attempts to define appropriate prior probabilities should continue to be considered as untenable for the need. PMID:17267153

Biedermann, A; Taroni, F; Garbolino, P

2007-10-25

181

STUDIES ON THE POSTERIOR SILK GLAND OF THE SILKWORM BOMBIX MORI

Ultracentrifugal analyses of the native silk proteins extracted from the various parts of the middle silk gland of the mature silkworm have revealed that there exist four components with S°20,w values of 10S, 9–10S, 9S, and 4S in the extract. It is suggested that the fastest 10S component is the native fibroin synthesized in the posterior silk gland and transferred to the middle silk gland to be stored there, while the slower three components probably correspond to inner, middle, and outer sericins which were synthesized in the posterior, middle, and anterior portion of the middle silk gland, respectively. Native fibroin solution was prepared from the most posterior part of the middle silk gland. Ultracentrifugal analyses have shown that the solution contains considerable amounts of aggregates in addition to the main 10S component. Treatment with lithium bromide (LiBr), urea, or guanidine hydrochloride solution up to 6 M all have failed to dissociate the 10S component. From the sedimentation equilibrium analyses and partial specific volume of 0.716, the molecular weight of the 10S component of the native fibroin solution was found to be between 3.2 – 4.2 x 105, with a tendency to lie fairly close to 3.7 x 105. PMID:5459009

Tashiro, Yutaka; Otsuki, Eiichi

1970-01-01

182

Defining Predictive Probability Functions for Species Sampling Models

We review the class of species sampling models (SSM). In particular, we investigate the relation between the exchangeable partition probability function (EPPF) and the predictive probability function (PPF). It is straightforward to define a PPF from an EPPF, but the converse is not necessarily true. In this paper we introduce the notion of putative PPFs and show novel conditions for a putative PPF to define an EPPF. We show that all possible PPFs in a certain class have to define (unnormalized) probabilities for cluster membership that are linear in cluster size. We give a new necessary and sufficient condition for arbitrary putative PPFs to define an EPPF. Finally, we show posterior inference for a large class of SSMs with a PPF that is not linear in cluster size and discuss a numerical method to derive its PPF. PMID:24368874

Lee, Jaeyong; Quintana, Fernando A.; Müller, Peter; Trippa, Lorenzo

2013-01-01

183

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.

2000-06-01

184

Alexia and agraphia in posterior cortical atrophy.

A 65-year-old woman with progressive visuospatial dysfunction for 2 years complained of later-onset associated memory impairment. MRI revealed diffuse cerebrocortical atrophy, which was especially severe in both parieto-occipital regions but spared the calcarine and pericalcarine cortices. Examination 5 years after onset revealed left visual hemi-neglect, oculomotor apraxia, optic ataxia, simultanagnosia, verbal alexia, lexical and spatial agraphia, and anterograde amnesia. This patient's disorder is considered in the context of previous reports on the array of cognitive disturbances associated with posterior cortical atrophy (pCA). Special emphasis is made on her reading and writing disturbances, because their prevalence and range of individual variability have not been established in pCA. This array of neuropsychological manifestations may help to distinguish among different clinical and etiological types of pCA, and to elucidate the pathophysiology of a syndrome that has been associated with conditions as diverse as Alzheimer's disease, subcortical gliosis, and prion diseases. The parameters described in our case may thus help to address these issues in clinico-pathological studies with large numbers of patients with pCA. PMID:9118197

Ardila, A; Rosselli, M; Arvizu, L; Kuljis, R O

1997-01-01

185

Composite resection of posterior pelvic malignancy.

Advanced pelvic cancer is a formidable challenge to surgical resection. These tumors commonly invade the bony pelvis, may involve other viscera, and usually have been irradiated previously. The authors are presenting experience with 76 patients who had composite resection of posterior or lateral pelvic malignancy. Fifty-eight patients had secondary cancers involving the musculoskeletal pelvis. This included 47 patients with advanced carcinoma of the rectum (41 curative, 6 palliative), 10 epidermoid cancers of the anorectum (8) or cervix (2), and 1 bladder cancer. Among the 18 patients with primary pelvic tumors were three patients with chordomas, six with bone tumors (osteosarcoma chondrosarcoma, grade III giant cell tumor), and nine with soft tissue tumors. All required major resection of the sacrum or pelvic side walls, and one half had an additional exenterative procedure. The overall mortality rate was 7.9%. Long-term estimated survival was 24% in patients having curative resection of recurrent rectal cancer, and 22.5% in 10 patients with advanced epidermoid cancer. Fifty per cent of patients with primary bone or soft tissue tumors survived from 13 to 88 months. Most patients had reasonable return of function, and were able to return to work or resume their normal previous lifestyle. PMID:1632689

Wanebo, H J; Koness, R J; Turk, P S; Cohen, S I

1992-06-01

186

A rare posterior cranial fossa tumor.

Among tumors of the central nervous system, tumors of the mixed glioneuronal type form an important recognized subset. Some of the examples for mixed glioneuronal tumors include gangliocytoma, dysembryoplastic neuroepithelial tumor (DNT), ganglioglioma, anaplastic ganglioglioma, and central neurocytoma. The rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a new entity that has only slowly emerged in the literature due to its prior classification with other low-grade mixed glial and neuronal tumors. These tumors are relatively infrequent lesions, and therefore, they can be challenging to diagnose for the practicing pathologist. This is a rare biphasic tumor with clearly defined neurocytic and glial components. The tumor is found exclusively in the posterior fossa, where it arises in the midline, usually occupying a substantial fraction of the fourth ventricle, and it is observed by magnetic resonance imaging (MRI) as a circumscribed, solid mass with heterogeneous contrast enhancement. We describe here a case of RGNT occurring in a 22-year-old male. PMID:23361291

Nandeesh, Bevinahalli N; Chabra, Manmeet Singh; Babu, Manjaly K; Chand, Ashish K

2012-01-01

187

Representation of numerosity in posterior parietal cortex

Humans and animals appear to share a similar representation of number as an analog magnitude on an internal, subjective scale. Neurological and neurophysiological data suggest that posterior parietal cortex (PPC) is a critical component of the circuits that form the basis of numerical abilities in humans. Patients with parietal lesions are impaired in their ability to access the deep meaning of numbers. Acalculiac patients with inferior parietal damage often have difficulty performing arithmetic (2 + 4?) or number bisection (what is between 3 and 5?) tasks, but are able to recite multiplication tables and read or write numerals. Functional imaging studies of neurologically intact humans performing subtraction, number comparison, and non-verbal magnitude comparison tasks show activity in areas within the intraparietal sulcus (IPS). Taken together, clinical cases and imaging studies support a critical role for parietal cortex in the mental manipulation of numerical quantities. Further, responses of single PPC neurons in non-human primates are sensitive to the numerosity of visual stimuli independent of low-level stimulus qualities. When monkeys are trained to make explicit judgments about the numerical value of such stimuli, PPC neurons encode their cardinal numerical value; without such training PPC neurons appear to encode numerical magnitude in an analog fashion. Here we suggest that the spatial and integrative properties of PPC neurons contribute to their critical role in numerical cognition. PMID:22666194

Roitman, Jamie D.; Brannon, Elizabeth M.; Platt, Michael L.

2012-01-01

188

Measurement Uncertainty and Probability

NASA Astrophysics Data System (ADS)

Part I. Principles: 1. Introduction; 2. Foundational ideas in measurement; 3. Components of error or uncertainty; 4. Foundational ideas in probability and statistics; 5. The randomization of systematic errors; 6. Beyond the standard confidence interval; Part II. Evaluation of Uncertainty: 7. Final preparation; 8. Evaluation using the linear approximation; 9. Evaluation without the linear approximations; 10. Uncertainty information fit for purpose; Part III. Related Topics: 11. Measurement of vectors and functions; 12. Why take part in a measurement comparison?; 13. Other philosophies; 14. An assessment of objective Bayesian methods; 15. A guide to the expression of uncertainty in measurement; 16. Measurement near a limit - an insoluble problem?; References; Index.

Willink, Robin

2013-02-01

189

Activation of the retrotrapezoid nucleus by posterior hypothalamic stimulation

The retrotrapezoid nucleus (RTN) contains chemically defined neurons (ccRTN neurons) that provide a pH-regulated excitatory drive to the central respiratory pattern generator. Here we test whether ccRTN neurons respond to stimulation of the perifornical hypothalamus (PeF), a region that regulates breathing during sleep, stress and exercise. PeF stimulation with gabazine increased blood pressure, phrenic nerve discharge (PND) and the firing rate of ccRTN neurons in isoflurane-anaesthetized rats. Gabazine produced an approximately parallel upward shift of the steady-state relationship between ccRTN neuron firing rate and end-tidal CO2, and a similar shift of the relationship between PND and end-tidal CO2. The central respiratory modulation of ccRTN neurons persisted after gabazine without a change in pattern. Morphine administration typically abolished PND and reduced the discharge rate of most ccRTN neurons (by 25% on average). After morphine administration, PeF stimulation activated the ccRTN neurons normally but PND activation and the central respiratory modulation of the ccRTN neurons were severely attenuated. In the same rat preparation, most (58%) ccRTN neurons expressed c-Fos after exposure to hypercapnic hyperoxia (6–7% end-tidal CO2; 3.5 h; no hypothalamic stimulation) and 62% expressed c-Fos under hypocapnia (?3% end-tidal CO2) after PeF stimulation. Under baseline conditions (?3% end-tidal CO2, hyperoxia, no PeF stimulation) few (11%) ccRTN neurons expressed c-Fos. In summary, most ccRTN neurons are excited by posterior hypothalamic stimulation while retaining their normal response to CNS acidification. ccRTN neurons probably contribute both to the chemical drive of breathing and to the feed-forward control of breathing associated with emotions and or locomotion. PMID:19752119

Fortuna, Michal G; Stornetta, Ruth L; West, Gavin H; Guyenet, Patrice G

2009-01-01

190

Activation of the retrotrapezoid nucleus by posterior hypothalamic stimulation.

The retrotrapezoid nucleus (RTN) contains chemically defined neurons (ccRTN neurons) that provide a pH-regulated excitatory drive to the central respiratory pattern generator. Here we test whether ccRTN neurons respond to stimulation of the perifornical hypothalamus (PeF), a region that regulates breathing during sleep, stress and exercise. PeF stimulation with gabazine increased blood pressure, phrenic nerve discharge (PND) and the firing rate of ccRTN neurons in isoflurane-anaesthetized rats. Gabazine produced an approximately parallel upward shift of the steady-state relationship between ccRTN neuron firing rate and end-tidal CO(2), and a similar shift of the relationship between PND and end-tidal CO(2). The central respiratory modulation of ccRTN neurons persisted after gabazine without a change in pattern. Morphine administration typically abolished PND and reduced the discharge rate of most ccRTN neurons (by 25% on average). After morphine administration, PeF stimulation activated the ccRTN neurons normally but PND activation and the central respiratory modulation of the ccRTN neurons were severely attenuated. In the same rat preparation, most (58%) ccRTN neurons expressed c-Fos after exposure to hypercapnic hyperoxia (6-7% end-tidal CO(2); 3.5 h; no hypothalamic stimulation) and 62% expressed c-Fos under hypocapnia (approximately 3% end-tidal CO(2)) after PeF stimulation. Under baseline conditions (approximately 3% end-tidal CO(2), hyperoxia, no PeF stimulation) few (11%) ccRTN neurons expressed c-Fos. In summary, most ccRTN neurons are excited by posterior hypothalamic stimulation while retaining their normal response to CNS acidification. ccRTN neurons probably contribute both to the chemical drive of breathing and to the feed-forward control of breathing associated with emotions and or locomotion. PMID:19752119

Fortuna, Michal G; Stornetta, Ruth L; West, Gavin H; Guyenet, Patrice G

2009-11-01

191

Probability Forecasting Using Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Space Situational Awareness (SSA) is defined as the knowledge and characterization of all aspects of space. SSA is now a fundamental and critical component of space operations. Increased dependence on our space assets has in turn lead to a greater need for accurate, near real-time knowledge of all space activities. With the growth of the orbital debris population, satellite operators are performing collision avoidance maneuvers more frequently. Frequent maneuver execution expends fuel and reduces the operational lifetime of the spacecraft. Thus the need for new, more sophisticated collision threat characterization methods must be implemented. The collision probability metric is used operationally to quantify the collision risk. The collision probability is typically calculated days into the future, so that high risk and potential high risk conjunction events are identified early enough to develop an appropriate course of action. As the time horizon to the conjunction event is reduced, the collision probability changes. A significant change in the collision probability will change the satellite mission stakeholder's course of action. So constructing a method for estimating how the collision probability will evolve improves operations by providing satellite operators with a new piece of information, namely an estimate or 'forecast' of how the risk will change as time to the event is reduced. Collision probability forecasting is a predictive process where the future risk of a conjunction event is estimated. The method utilizes a Monte Carlo simulation that produces a likelihood distribution for a given collision threshold. Using known state and state uncertainty information, the simulation generates a set possible trajectories for a given space object pair. Each new trajectory produces a unique event geometry at the time of close approach. Given state uncertainty information for both objects, a collision probability value can be computed for every trail. This yields a collision probability distribution given known, predicted uncertainty. This paper presents the details of the collision probability forecasting method. We examine various conjunction event scenarios and numerically demonstrate the utility of this approach in typical event scenarios. We explore the utility of a probability-based track scenario simulation that models expected tracking data frequency as the tasking levels are increased. The resulting orbital uncertainty is subsequently used in the forecasting algorithm.

Duncan, M.; Frisbee, J.; Wysack, J.

2014-09-01

192

Accurate models for EUV lithography

Accurate modeling of EUV Lithography is a mandatory step in driving the technology towards its foreseen insertion point for 22-16nm node patterning. The models are needed to correct EUV designs for imaging effects, and to understand and improve the CD fingerprint of the exposure tools. With a full-field EUV ADT from ASML now available in the IMEC cleanroom, wafer data

Eric Hendrickx; Gian F. Lorusso; Jiong Jiang; Luoqi Chen; Wei Liu; Eelco van Setten; Steve Hansen

2009-01-01

193

Positioning of the posterior cruciate ligament.

The isometric position in ligament reconstruction is the one in which there is little or no change in the length of the graft with range of motion of the joint. It varies according to the positions of the tunnels that will become the attachment sites of whatever graft is being used. Better understanding of this concept that greatly improved the surgical results of intra-articular reconstructions of the anterior cruciate ligament. Unfortunately, the results of posterior cruciate ligament (PCL) reconstructions have lagged behind. A better understanding of the isometry of the PCL and how it relates to the positioning of a graft at the time of reconstruction should help improve the situation. The current scientific studies on the PCL as they relate to isometry are evaluated and summarised in this paper. The tibial isometric point was universally less sensitive to changes in position than was the femoral isometric point. However, all the points that were evaluated for the tibia fell within the normal insertion area of the PCL. This has important ramifications when extrapolating these laboratory studies to the operating room, where it is imperative to get the tibial tunnel or attachment site distal enough on the tibia so that it will be in the usual anatomic location of the PCL. There is less uniformity when it comes to the femoral isometric point, but once again the isometric point from each of the studies fell within the normal anatomic femoral attachment site. The differences between the selected points may be explained by the different study designs. PMID:7584194

Juergensen, K; Edwards, J C; Jakob, R P

1994-01-01

194

Posterior Urethral Valves; A single Center Experience

Objective Posterior urethral valves (PUV) are the most common cause of bladder outlet obstruction in infancy that impair renal and bladder function. This study was planned to evaluate and record the various clinical presentations and management, complications, and surgical management and long-term outcome of PUV. Methods In a retrospective study, 98 patients who have been treated for PUV are evaluated in Mofid Children's Hospital from January 2007 to December 2012. Detailed history taken and paraclinical examinations were performed in each patient and diagnosis was confirmed by voiding-cysto-urethrography (VCUG). PUV had been ablated in 62 patients by electric hook, and diversion was performed in 42 (42.85%) cases. Data were analyzed by SPSS software version18. Findings Totally 98 patients with mean age at diagnosis 62 (±13) days were included in this study. Fifty seven cases had been catheterized within one to 6 days of life (mean age one day), PUV was ablated in 62 patients by electric hook, and diversion was performed in 42 cases. The most common symptom in our group was dribbling poor stream 51% and urinary tract infection (UTI) 40.8%. There was vesico-ureteral-reflux (VUR) in 61.2%, and hydronephrosis in 82.6%. Most common associated anomaly was kidney anomalies (multicystic kidney disease and renal agenesis/dysplasia) in 8 (8.2%) patients. Twenty patients had prenatal diagnosis of PUV. Complication occurred in three (3.1%) patients. Mortality occurred in 5 (5.1%) patients. Mean follow-up period was 3.4±1.2 years (1.5 months to 5 years). Conclusion Urinary drainage by feeding tube in early days of infancy, followed by valve ablation is the best treatment in PUV, and urinary diversion improves the outcome. VCUG is still the gold-standard imaging modality for documenting PUVs. The factors like renal dysplasia and UTI have their role in final outcome. PMID:24800012

Mirshemirani, Alireza; Khaleghnejad, Ahmad; Rouzrokh, Mohsen; Sadeghi, Afsaneh; Mohajerzadeh, Leila; Sharifian, Mustafa

2013-01-01

195

53Probability, Verbal Expressions of Marginal Probability of Discrete Variables

Independence; Conditional Probability; Diagnostic Tests; Odds and Odds Ratio, Risk Ratio; Probability, Verbal, such as "The probabil ity of X is 70%" or "The odds are 3 to 1." Correspondence Between Verbal and Numerical

Druzdzel, Marek J.

196

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.

2005-01-01

197

Probabilities for Solar Siblings

We have shown previously (Bobylev et al 2011) that some of the stars in the Solar neighborhood today may have originated in the same star cluster as the Sun, and could thus be called Solar Siblings. In this work we investigate the sensitivity of this result to Galactic models and to parameters of these models, and also extend the sample of orbits. There are a number of good candidates for the Sibling category, but due to the long period of orbit evolution since the break-up of the birth cluster of the Sun, one can only attach probabilities of membership. We find that up to 10% (but more likely around 1 %) of the members of the Sun's birth cluster could be still found within 100 pc from the Sun today.

Valtonen, M; Bobylev, V V; Myllari, A

2015-01-01

198

Probabilities for Solar Siblings

NASA Astrophysics Data System (ADS)

We have shown previously (Bobylev et al. Astron Lett 37:550-562, 2011) that some of the stars in the solar neighborhood today may have originated in the same star cluster as the Sun, and could thus be called Solar Siblings. In this work we investigate the sensitivity of this result to galactic models and to parameters of these models, and also extend the sample of orbits. There are a number of good candidates for the sibling category, but due to the long period of orbit evolution since the break-up of the birth cluster of the Sun, one can only attach probabilities of membership. We find that up to 10 % (but more likely around 1 %) of the members of the Sun's birth cluster could be still found within 100 pc from the Sun today.

Valtonen, Mauri; Bajkova, A. T.; Bobylev, V. V.; Mylläri, A.

2015-02-01

199

Posterior mediastinal mass diagnosed as schwanomma with concomittant tuberculosis.

A 21-year-old non-smoker, non-hypertensive male without diabetes was referred to our pulmonary medicine department with suspected malignant intrathoracic mass. The clinicoradiological evaluation revealed that it could be a posterior mediastinal mass. The same diagnosis was confirmed on performing CT and MRI. Benign posterior mediastinal schwanomma was suspected as it is the most common posterior mediastinal mass. It was completely resected. Histopathological examination confirmed the same. The mass was also sent for culture for mycobacterium which came out to be positive. The patient recovered from the surgery and postoperative X-ray showed complete clearance. He was treated with antitubercular treatment and responded very well. PMID:25246469

Tripathi, Surya Kant; Mishra, Ashwini Kumar; Verma, Ajay Kumar; Prakash, Ved

2014-01-01

200

Intro Probability Rabbits Description Predictions Ontology of Earthquake Probability: Metaphor

rather than knowledge: They amount to saying that earthquakes occur as if according to a casino game Earthquake probabilities are based on a metaphor Â· Earthquakes occur "as if" in a casino game whose rulesIntro Probability Rabbits Description Predictions Ontology of Earthquake Probability: Metaphor

Stark, Philip B.

201

21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

Code of Federal Regulations, 2010 CFR

...false Posterior artificial tooth with a metal insert. 872.3900 Section 872...3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is a porcelain device with...

2010-04-01

202

Accurate Probability Calibration for Multiple Classifiers Leon Wenliang Zhong James T. Kwok

be known during training. In order to make cost-sensitive decisions, probabil- ity is again an essential strengths, a combination of them can lead to better performance. In this paper, we propose a novel component in the computation of the conditional risk [Zadrozny and Elkan, 2001]. However, many popular

Kwok, James Tin-Yau

203

NASA Astrophysics Data System (ADS)

Results from multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) calculations are presented for the n=3 to n?=3 transitions in the Mg isoelectronic sequence. The calculated values for the lowest 35 levels including core-valence correlation are found to be similar and to compare very well with other theoretical and experimental values. The Breit interaction and leading quantum electrodynamic effects are included as perturbations. The calculations can provide useful data for the experimental study of determining the fine structure levels in future work.

Hu, Feng; Mei, Maofei; Han, Chong; Han, Baiping; Jiang, Gang; Yang, Jiamin

2014-12-01

204

Fast and accurate database searches with MS-GF+Percolator

To identify peptides and proteins from the large number of fragmentation spectra in mass spectrometrybased proteomics, researches commonly employ so called database search engines. Additionally, postprocessors like Percolator have been used on the results from such search engines, to assess confidence, infer peptides and generally increase the number of identifications. A recent search engine, MS-GF+, has previously been showed to out-perform these classical search engines in terms of the number of identified spectra. However, MS-GF+ generates only limited statistical estimates of the results, hence hampering the biological interpretation. Here, we enabled Percolator-processing for MS-GF+ output, and observed an increased number of identified peptides for a wide variety of datasets. In addition, Percolator directly reports false discovery rate estimates, such as q values and posterior error probabilities, as well as p values, for peptide-spectrum matches, peptides and proteins, functions useful for the whole proteomics community.

Granholm, Viktor; Kim, Sangtae; Navarro, Jose' C.; Sjolund, Erik; Smith, Richard D.; Kall, Lukas

2014-02-28

205

ERIC Educational Resources Information Center

Two contestants debate the notorious probability problem of the sex of the second child. The conclusions boil down to explication of the underlying scenarios and assumptions. Basic principles of probability theory are highlighted.

Falk, Ruma; Kendig, Keith

2013-01-01

206

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

2014-09-16

207

Predicting most probable conformations of a given peptide sequence in the random coil state.

In this work, we present a computational scheme for finding high probability conformations of peptides. The scheme calculates the probability of a given conformation of the given peptide sequence using the probability distribution of torsion states. Dependence of the states of a residue on the states of its first neighbors along the chain is considered. Prior probabilities of torsion states are obtained from a coil library. Posterior probabilities are calculated by the matrix multiplication Rotational Isomeric States Model of polymer theory. The conformation of a peptide with highest probability is determined by using a hidden Markov model Viterbi algorithm. First, the probability distribution of the torsion states of the residues is obtained. Using the highest probability torsion state, one can generate, step by step, states with lower probabilities. To validate the method, the highest probability state of residues in a given sequence is calculated and compared with probabilities obtained from the Coil Databank. Predictions based on the method are 32% better than predictions based on the most probable states of residues. The ensemble of "n" high probability conformations of a given protein is also determined using the Viterbi algorithm with multistep backtracking. PMID:22955874

Bayrak, Cigdem Sevim; Erman, Burak

2012-11-01

208

Magnetic source imaging in posterior cortex epilepsies.

Posterior cortex epilepsies (PCE) are characterized by less satisfying postoperative results than temporal lobe epilepsies and are thus challenging for non-invasive presurgical investigations. The objective of this study was to evaluate the performance of magnetic source imaging (MSI) in PCE, validating the results by the SEEG (stereoelectroencephalography) definition of irritative and epileptogenic zones (IZ and EZ). Fourteen PCE surgery candidates were investigated using MSI and SEEG. LCMV (Linearly Constrained Minimum Variance) and MUSIC algorithms were used. IZ was quantified using a semi-automatic detection of interictal spikes. EZ was quantified using the epileptogenicity index (EI) method that accounts for both the propensity of a brain area to generate rapid discharges and the time for this area to get involved in the seizure. EI values range from 0 (no epileptogenicity) to 1 (maximal epileptogenicity). Levels of concordance between MSI and IZ, MSI and EZ were determined as follows: A = localized on MSI and SEEG for the site of value 1 (IZ and EZ quantification), B = localized on MSI and SEEG for a part of the IZ or a structure involved in the EZ (without the maximal value 1), C = localized on MSI and not SEEG, D = localized on SEEG and not MSI, E = localized on MSI and SEEG, discordant for site. Five PCE cases were characterized by focal IZ, nine by distributed IZ between several distant brain areas. MSI allowed to determinate IZ in 4/5 focal IZ cases. In case of distributed IZ, levels of concordance were A (2 cases), B (4 cases) and D (3 cases). In most distributed cases, MSI allowed to localize only a part of the IZ. Medial temporal involvement in the IZ was frequent (9/12 cases) and not evidenced by MSI. The brain area that demonstrated the maximal value of EI was shown by MSI in four out of five (80 %) focal IZ cases, in two out of nine (22 %) distributed cases. MSI results depend on IZ characteristics. A distributed IZ organization presents difficulties for MSI and highlights the need for further methodological approaches. PMID:25352165

Badier, Jean-Michel; Bartolomei, Fabrice; Chauvel, Patrick; Bénar, Christian-George; Gavaret, Martine

2015-01-01

209

Vitrectorhexis versus forceps posterior capsulorhexis in pediatric cataract surgery

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

2013-01-01

210

Free posterior tibial flap reconstruction for hypopharyngeal squamous cell carcinoma

Objectives The aim of this article was to determine outcomes in patients with squamous cell carcinoma of the hypopharynx (SCCHP) in whom the free posterior tibial flap was used for primary reconstruction of hypopharynx defects after cancer resection. Subjects and methods Between August 2009 and February 2012, 10 patients with SCCHP underwent posterior tibial flap reconstruction for hypopharynx defects. The corresponding clinical data were retrospectively collected and analyzed. Results Despite the multistep and time-consuming procedure, the posterior tibial flap survival rate was 100%. Operation-induced complications did not occur in four patients. Six patients developed postoperative hypoproteinemia, four patients developed postoperative pulmonary infections, and four patients developed pharyngeal fistula. The pharyngeal and laryngeal functions of all patients were preserved. Conclusion Our experience demonstrates that the posterior tibial flap is a safe and reliable choice for the reconstruction of hypopharynx defects. PMID:24884631

2014-01-01

211

Spectral and Temporal Processing in Rat Posterior Auditory Cortex

these areas. To determine the filter properties of rat posterior auditory field (PAF) neurons, we compared of narrowband one octave FM sweeps. These results indicate that PAF, like non- primary visual fields, processes

Kilgard, Michael P.

212

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.

2007-01-01

213

Palinopsia from posterior visual pathway lesions without visual field defects.

Palinopsia, or perseveration of a previously viewed image, may be caused by drug use or by posterior visual pathway lesions. Most cases of palinopsia due to visual pathway lesions have an associated homonymous hemianopic visual field defect. We report two patients with palinopsia caused by structural lesions of the posterior visual pathway in the absence of visual field defects. Patients with palinopsia should undergo neuroimaging even in the presence of normal visual fields. PMID:17548995

Ritsema, Molly E; Murphy, Marjorie A

2007-06-01

214

Which Approach for Total Hip Arthroplasty: Anterolateral or Posterior?

The best approach to use when performing THA is controversial. We did a prospective, nonrandomized multicenter study of 1089\\u000a THAs to evaluate patient-centered hip scores and dislocation and revision rates when comparing anterolateral and posterior\\u000a hip approaches at 5 years’ followup. Patients were divided into two groups depending on which surgical approach was used:\\u000a anterolateral or posterior. The primary outcome measure

Jeya Palan; David J. Beard; David W. Murray; J. G. Andrew; John Nolan

2009-01-01

215

Posterior partially edentulous jaws, planning a rehabilitation with dental implants

AIM: To discuss important characteristics of the use of dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE (PubMed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations (bone quantity and density), radiographic techniques, implant selection (number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning. PMID:25610852

Monteiro, Douglas R; Silva, Emily V F; Pellizzer, Eduardo P; Filho, Osvaldo Magro; Goiato, Marcelo C

2015-01-01

216

Post-Intubation Tracheoesophageal Fistula with Posterior Glottic Web

Tracheoesophageal fistula (TEF) after prolonged intubation could present as chronic aspiration and could be mistaken as unilateral or bilateral vocal fold palsy, especially when there was combined posterior glottic synechia. We present a case of post-intubation TEF which was successfully treated with tracheal resection and anastomosis with primary esophageal closure. The accompanying posterior glottic web was treated by endoscopic technique of web lysis, with topical application of mitomycin C solution. PMID:21716949

Lee, Ji-Eun; Chang, Mun-Young; Kim, Kwang Hyun

2011-01-01

217

Late posterior failure after mitral valve repair in degenerative disease

Objectives: Little is known regarding the mechanisms, the feasibility and the long-term results of re-repair in ‘posterior failure’ of a previous mitral valve repair performed for severe degenerative mitral regurgitation. We report our 16-year experience in redo surgery for late posterior failure of mitral valve repair in degenerative disease. Methods: From 1991 to 2004, 13 consecutive patients (10 males; median

Rachid Zegdi; Ghassan Sleilaty; Ziad Khabbaz; Milena Noghin; Christian Latrémouille; Alain Carpentier; Alain Deloche; Jean-Noël Fabiani

2008-01-01

218

Influence of persistent occiput posterior position on delivery outcome

OBJECTIVE:To evaluate the influence of intrapartum persistent occiput posterior position of the fetal head on delivery outcome and anal sphincter injury, with reference to the association with epidural analgesia.METHODS:We conducted a prospective observational study of 246 women with persistent occiput posterior position in labor during a 2-year period, compared with 13,543 contemporaneous vaginal deliveries with occiput anterior position.RESULTS:The incidence of

Myra Fitzpatrick; Kathryn McQuillan; Colm O’Herlihy

2001-01-01

219

Successful choice under risk requires the integration of information about outcome probabilities and values and implicates a brain network including the ventromedial prefrontal cortex (vmPFC) and posterior parietal cortex (pPAR). Damage to the vmPFC is linked to poor decision-making and increased risk-taking. Electrophysiological and neuroimaging data implicate the pPAR in the processing of reward probability during choice, but the causal contribution of this area has not been established. We compared patients with lesions to the pPAR (n = 13), vmPFC (n = 13), and healthy volunteers (n = 22) on the Roulette Betting Task, a measure of risk-sensitive decision-making. Both lesion groups were impaired in adjusting their bets to the probability of winning. This impairment was correlated with the extent of pPAR, but not vmPFC, damage. In addition, the vmPFC group chose higher bets than healthy controls overall, an effect that correlated with lesion volume in the medial orbitofrontal cortex. Both lesion groups earned fewer points than healthy controls. The groups did not differ on 2 tasks assessing probabilistic reasoning outside of a risk-reward context. Our results demonstrate the causal involvement of both the pPAR and vmPFC in risk-sensitive choice and indicate distinguishable roles of these areas in probability processing and risk appetite. PMID:23926113

Studer, Bettina; Manes, Facundo; Humphreys, Glyn; Robbins, Trevor W.; Clark, Luke

2015-01-01

220

Probability-density function model of turbulent hydrogen flames

Hydrogen combustion attracted much attention recently because of the need for clean alternative energy. For the theoretical\\/numerical study of hydrogen combustion, there is a need for modeling capabilities for turbulent hydrogen flames. The present work examines the applicability of probability density function (pdf) turbulence models. For the purpose of accurate prediction of turbulent combustion, an algorithm that combines a conventional

A. T. Hsu; G.-B. He

2000-01-01

221

Probability density function method for turbulent hydrogen flames

Hydrogen combustion attracted much attention recently because of the need for a clean alternative energy. For the theoretical\\/numerical study of hydrogen combustion, there is a need for modeling capabilities for turbulent hydrogen flames. The present work examines the applicability of probability density function (pdf) turbulence models. For the purpose of accurate prediction of turbulent combustion, an algorithm that combines a

A. t. Hsu; G.-B. He

1999-01-01

222

Accurate extraction of the News

We propose a new scheme for extracting gravitational radiation from a characteristic numerical simulation of a spacetime. This method is similar in conception to our earlier work but analytical and numerical implementation is different. The scheme is based on direct transformation to the Bondi coordinates and the gravitational waves are extracted by calculating the Bondi news function in Bondi coordinates. The entire calculation is done in a way which will make the implementation easy when we use uniform Bondi angular grid at $\\mathcal I^+$. Using uniform Bondi grid for news calculation has added advantage that we have to solve only ordinary differential equations instead of partial differential equation. For the test problems this new scheme allows us to extract gravitational radiation much more accurately than the previous schemes.

Shrirang S. Deshingkar

2006-09-14

223

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.

1974-01-01

224

Incompatible stochastic processes and complex probabilities

The definition of conditional probabilities is based upon the existence of a joint probability. However, a reconstruction of the joint probability from given conditional probabilities imposes certain constraints upon the latter, so that if several conditional probabilities are chosen arbitrarily, the corresponding joint probability may not exist. Such an incompleteness in conditional probabilities can be eliminated by introducing complex probabilities.

Michail Zak

1998-01-01

225

[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

2001-09-01

226

Accurate models for EUV lithography

NASA Astrophysics Data System (ADS)

Accurate modeling of EUV Lithography is a mandatory step in driving the technology towards its foreseen insertion point for 22-16nm node patterning. The models are needed to correct EUV designs for imaging effects, and to understand and improve the CD fingerprint of the exposure tools. With a full-field EUV ADT from ASML now available in the IMEC cleanroom, wafer data can be collected to calibrate accurate models and check if the existing modeling infrastructure can be extended to EUV lithography. As a first topic, we have measured the CD on wafer of a typical OPC dataset at different flare levels and modeled the evolution of wafer CD through flare, reticle CD, and pitch using Brion's Tachyon OPC engine. The modeling first requires the generation of a flare map using long-range kernels to model the EUV specific long-range flare. The accuracy of the flare map can be established independently from the CD measurements, by using the traditional disappearing pad test for flare determination (Kirk test). The flare map is then used as background intensity in the calibration of the traditional optical models with short-range kernels. For a structure set of 600 features and over a flare range of 4-6%, an rms fit value of 0.9nm was obtained. As a second aspect of the modeling, we have calibrated a full resist model to process window data. The full resist model is then used in a combination with experimental measurements of reticle CD, slit intensity uniformity, focal plane behavior, and EUV thick mask effects to model the evolution of wafer CD across the exposure field. The modeled evolution of CD across the exposure field was found to be a good match to the experimentally seen evolution of CD across the field, and confirms that the 4 factors mentioned above are main contributions to the CD uniformity across the field. As such the modeling work enables a better understanding of the errors contributing to CD variation across the field for EUV technology.

Hendrickx, Eric; Lorusso, Gian F.; Jiang, Jiong; Chen, Luoqi; Liu, Wei; Van Setten, Eelco; Hansen, Steve

2009-10-01

227

Subjective Probabilities in Household Surveys

Subjective probabilities are now collected on a number of large household surveys with the objective of providing data to better understand inter-temporal decision making. Comparison of subjective probabilities with actual outcomes shows that the probabilities have considerable predictive power in situations where individuals have considerable private information such as survival and retirement. In contrast the subjective probability of a stock market gain varies greatly across individuals even though no one has private information and the outcome is the same for everyone. An explanation is that there is considerable variation in accessing and processing information. Further, the subjective probability of a stock market gain is considerably lower than historical averages, providing an explanation for the relatively low frequency of stock holding. An important research objective will be to understand how individuals form their subjective probabilities. PMID:21643535

Hurd, Michael D.

2011-01-01

228

Posterior tibial slope in medial opening-wedge high tibial osteotomy: 2-D versus 3-D navigation.

Although opening-wedge high tibial osteotomy (HTO) is used to correct deformities, it can simultaneously alter tibial slope in the sagittal plane because of the triangular configuration of the proximal tibia, and this undesired change in tibial slope can influence knee kinematics, stability, and joint contact pressure. Therefore, medial opening-wedge HTO is a technically demanding procedure despite the use of 2-dimensional (2-D) navigation. The authors evaluated the posterior tibial slope pre- and postoperatively in patients who underwent navigation-assisted opening-wedge HTO and compared posterior slope changes for 2-D and 3-dimensional (3-D) navigation versions. Patients were randomly divided into 2 groups based on the navigation system used: group A (2-D guidance for coronal alignment; 17 patients) and group B (3-D guidance for coronal and sagittal alignments; 17 patients). Postoperatively, the mechanical axis was corrected to a mean valgus of 2.81° (range, 1°-5.4°) in group A and 3.15° (range, 1.5°-5.6°) in group B. A significant intergroup difference existed for the amount of posterior tibial slope change (? slope) pre- and postoperatively (P=.04).Opening-wedge HTO using navigation offers accurate alignment of the lower limb. In particular, the use of 3-D navigation results in significantly less change in the posterior tibial slope postoperatively than does the use of 2-D navigation. Accordingly, the authors recommend the use of 3-D navigation systems because they provide real-time intraoperative information about coronal, sagittal, and transverse axes and guide the maintenance of the native posterior tibial slope. PMID:23026255

Yim, Ji Hyeon; Seon, Jong Keun; Song, Eun Kyoo

2012-10-01

229

External Dacryocystorhinostomy with and Without Suturing the Posterior Mucosal Flaps

ABSTRACT Purpose: To evaluate the outcome of the external dacryocystorhinostomy with and without suturing the posterior mucosal flaps. Methods: This study included 106 patients with lacrimal drainage system disorders who underwent the external dacryocystorhinostomy. Fifty four patients (Group A) underwent external dacryocystorhinostomy with suturing anterior and posterior flaps of the lacrimal sac and nasal mucosa, and the results obtained were compared with those of another series of 52 patients (Group B) where dacryocystorhinostomy was performed with suturing only the anterior flaps, whereas posterior mucosal flaps were excised. Results: The success rate was evaluated by lacrimal patency to irrigation and relief of epiphora. Patency achieved in groups A and B was 94.4% and 96.2%, respectively. There was no statistically significant difference in success rate between the groups. Conclusion: Our study suggests that external dacryocystorhinostomy with suturing anterior and posterior flaps have no advantage over dacryocystorhinostomy with suturing only anterior flaps. Anastomosis by suturing only anterior flaps and excision of the posterior flaps is easier to perform and may improve the success rate of external dacryocystorhinostomy. PMID:24783915

Kaçaniku, Gazmend; Begolli, Ilir

2014-01-01

230

Posterior myocardial infarction: the dark side of the moon.

The clinical presentation of posterior myocardial infarction is not always easy, not even for the cardiologist. In this article a 70-year-old woman who presented with chest pain is described. The electrocardiogram at presentation showed marked ST-segment depression in leads V(1) to V(5) and slight ST-segment depression in leads I and aVL. There was ST-segment elevation in the posterior leads V(7) to V(9). Elevation of specific cardiac enzymes confirmed the diagnosis of myocardial infarction. True posterior myocardial infarction is difficult to recognise because the leads of the standard 12-lead electrocardiogram are not a direct representation of the area involved. Only with indirect changes in the precordial leads as such the diagnosis can be suspected. This review will highlight the electrocardiographic fine-tuned diagnosis of posterior myocardial infarction by using the posterior leads V(7) to V(9) leading to easier and faster recognition with consequences for treatment and improved prognosis. (Neth Heart J 2007;15:16-21.). PMID:17612703

van Gorselen, E O F; Verheugt, F W A; Meursing, B T J; Oude Ophuis, A J M

2007-01-01

231

Surgical approaches to posterior polar cataract: a review

The aim of this study is to provide a comprehensive overview of surgical methods used in the emulsification of posterior polar cataracts (PPCs) that have been devised to minimize the risk of posterior capsule rupture (PCR) and its consequences. A Pubmed and Medline search of relevant literature on PPC was done. Only articles relevant to the treatment of PPC were included. The posterior capsule in eyes with PPC are known to have an abnormal adhesion to the polar opacity or a pre-existing weakness of the capsule that predisposes the eye to PCR. To circumvent the consequences of cleaving the abnormal adhesion, a majority of the surgeons use the anterior approach through the limbus, whereas some advocate the posterior approach through the pars plana. Emulsifying the nucleus and cleaving the central opacity of the PPC off the posterior capsule without disrupting its integrity provides optimal surgical outcomes. To achieve this, various modifications have been applied by surgeons during different phases of surgery. The advantages, disadvantages, complications, and results of each method have been discussed. Phacoemulsification is the preferred technique for removing PPC. This review will provide methods to avoid and /or deal with intraocular surgical difficulties that can arise during emulsification. Employing these would result in least ocular morbidity and satisfactory visual outcomes for the patient. This is particularly relevant given the major advancements in technology and refinements in surgical techniques in phacoemulsification. PMID:22441026

Vasavada, A R; Raj, S M; Vasavada, V; Shrivastav, S

2012-01-01

232

Background: Pain control is one of the most important factors for successful treatment. Each new measure to control pain has been looked as miraculous act at the initial stages. The improvements in agents and techniques for local anaesthesia are probably the most important advances in dental science to have occurred in the past years. Aim: To evaluate 4% articaine hydrochloride against 2% lignocaine hydrochloride anaesthesia in providing adequate palatal anaesthesia in maxillary posterior regions, without the need for a palatal block. Settings and Design: Healthy patients above 15 y of age and requiring bilateral extraction of their maxillary posterior teeth were included in this crossover study. The exclusion criteria included medical history of cardiovascular and kidney diseases, gastrointestinal bleeding or ulceration, allergic reactions to local anaesthetic, pregnancy or current lactation. Materials and Methods: Eighty patients, requiring bilateral extraction of their teeth due to various reasons were enrolled for this study. Each patient received both lignocaine and articaine anaesthetic in equivalent dose at two different appointments. Maxillary infiltration technique was used for extraction of maxillary posterior teeth at both the appointments. A 170-mm Heft Parker visual analogue scale was used to assess the pain on the palatal mucosa after buccal infiltration of either anaesthetic agent. Blood pressure, Pulse rate and electrocardiographic monitoring were done during the procedure. Adverse effects during the study period were also monitored. Statistical Analysis: Data was analysed by Z-test and student’s t-test. Results: Pain scores on probing palatal mucosa after buccal infiltration of the anaesthetic were more for lignocaine as compare to articaine and it was statistically significant (p <.001). However, for hemodynamic parameters and electrocardiographic monitoring, there was no statistically significant difference in blood pressure, pulse rate and electrocardiograph before and after the completion of extraction (p > 0.05). Conclusion: Four percent articaine offers better clinical performance than 2% Lignocaine, particularly in terms of providing adequate palatal anaesthesia with only buccal infiltration.

Sharma, Amit; Aseri, ML; Batta, Angelika; Singh, Vikas; Pilania, Dinesh; Kumar Sharma, Yogesh

2014-01-01

233

Posterior cortical atrophy: an exemplar for renovating diagnostic formulation in neuropsychiatry.

Neurodegenerative dementias represent among the most clinically and pathologically complex syndromes in neuropsychiatry. Phenomenologically protean, and often initially presenting with subtle subsyndromal characteristics, neurodegenerative behavioral syndromes can manifest with an assortment of cognitive, mood, personality, and comportmental changes, often alloyed with elementary neurologic (e.g., motor) signs. A range of pathogenic mechanisms (e.g., amyloid plaques, Pick bodies, etc) typically underlie corresponding clinical syndromes. However, overlap in both clinical expression and histopathologic comorbidities frequently exist among cortical and subcortical neurodegenerative disorders. Moreover, secondary central nervous system pathologies (e.g., cerebrovascular disease) commonly coexist with neurodegenerative processes, further complicating clinical phenomenology-based nosologic categorization. Evolving insight into the etiologic mechanisms of neurodegenerative dementias, and correspondingly improving potential for intervention, require more precise differentiation among dementia subtypes and comprehensive identification of contemporaneous neurodegenerative processes. Increasing appreciation of this diagnostic complexity is prompting the need for renovation of existing diagnostic schemas. We address these issues by reviewing the atypical dementia type known as posterior cortical atrophy. We then use posterior cortical atrophy as an exemplar for renovating neuropsychiatric diagnostic classification to better account for the layered complexity of clinical and pathologic domains needing to be characterized to accurately and completely diagnose neuropsychiatric disturbances. PMID:21497228

Goldstein, Martin A; Ivanov, Iliyan; Silverman, Michael E

2011-01-01

234

Surgical reconstruction of the posterior cruciate ligament (PCL) is technically demanding. Potential challenges include visualization of the tibial footprint and drilling of the tibial tunnel without damaging posterior neurovascular structures, as well as graft selection, deployment, tensioning, and fixation. We present a novel TransMedial all-inside arthroscopic technique (technique designed by A. J. Wilson with support from Arthrex) using a single hamstring tendon graft, fixed with adjustable cortical suspensory devices. The technique simplifies the difficult steps encountered during PCL reconstruction and is safe and reproducible. All arthroscopic viewing is accomplished from the lateral portal, and femoral socket preparation is performed from the medial side with specially contoured instruments, which allow accurate marking, measuring, and anatomic positioning of the graft. The quadrupled semitendinosus graft can be augmented with composite polymer tape for increased strength and initial stability. We use outside-in drilling to create retrograde femoral and tibial sockets. Cortical suspensory fixation on the tibial side can be supplemented with anchor fixation. We use an arthroscopic tibial inlay technique that better approximates native knee anatomy. This also avoids the “killer turn,” a problem seen in transtibial PCL reconstruction techniques, which theoretically induces graft laxity due to abrasion with cyclic loading. This technique can be further adapted to allow a modified double-bundle or TriLink graft (technique designed by A. J. Wilson with support from Arthrex.). PMID:24400186

Nancoo, Tamara J.; Lord, Breck; Yasen, Sam K.; Smith, James O.; Risebury, Michael J.; Wilson, Adrian J.

2013-01-01

235

The relationship between species detection probability and local extinction probability

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.

2004-01-01

236

38 CFR 4.46 - Accurate measurement.

Code of Federal Regulations, 2010 CFR

...46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect to landmarks, should be insisted on. The use of a goniometer in the measurement of limitation of motion...

2010-07-01

237

Posterior reversible encephalopathy syndrome: a neurologic phenomenon in cancer patients.

Posterior reversible encephalopathy syndrome is a well-recognized entity associated with a variety of benign and malignant conditions. This syndrome typically manifests itself with headache, visual loss, and seizures. Radiographic abnormalities consist of white matter edema involving the posterior parietal and occipital lobes, manifested as increased T2 and fluid-attenuated inversion recovery signal intensity on magnetic resonance imaging. In the last decade, there has been a reported increase in the incidence of posterior reversible encephalopathy syndrome in cancer patients. The diagnosis can be challenging in this patient population. Early recognition and initiation of appropriate therapy with removal of the causative agent is essential in order to prevent permanent neurologic sequelae. PMID:24595679

Le, Eileen M; Loghin, Monica E

2014-05-01

238

Posterior mediastinal branchial cleft cyst: an unusual site.

A two and a half year old Kenyan girl presented with recurrent chest infections and difficulty in swallowing. Her clinical and laboratory workup was suggestive of lower respiratory tract infection for which she received a course of antibiotics; however, she remains symptomatic after the management of her suspected diagnosis. Therefore, further radiological workup including a chest CT scan and barium study were performed. This showed a homogeneous mass surrounded by ascending and descending aorta in the posterior mediastinum that was compressing the middle esophagus. She had a posterolateral thoracotomy which revealed a cystic mass with smooth surfaces (5x5 cm) in the posterior mediastinum. Histopathology showed branchial cleft cyst predominately lined by stratified squamous epithelium, with lymphocytes predominance. A final diagnosis of posterior mediastinal branchial cleft cyst was made. She was discharged home and remained well at follow-up. PMID:24906261

Rashid, Abdul; Ahmad, Vaqas; Qazi, Saqib; Billoo, Abdul Gaffar; Rashid, Sajida; Saleem, Ali Faisal

2014-05-01

239

Rupture of Posterior Cruciate Ligament: Diagnosis and Treatment Principles

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

2011-01-01

240

Endothelin: A novel peptide in the posterior pituitary system

Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions.

Yoshizawa, Toshihiro; Kanazawa, Ichiro; Shinmi, Osamu; Kimura, Sadao; Yanagisawa, Masashi; Masaki, Tomoh; Uchiyama, Yasuo (Univ. of Tsukuba (Japan)); Giaid, A.; Gibson, S.J.; Polak, J.M. (Royal Postgraduate Medical School, London (England))

1990-01-26

241

Infundibular dilatation of the posterior communicating artery in a defined population.

Unusual widening of the posterior communicating artery (PCoA) at its beginning from the cerebral portion of the internal carotid artery (ICA) was described as its infundibular dilatation (ID). A possibility of ID rupture or progression to aneurysm was the reason for an investigation of its frequency and morphologic features in specimens of the Serbian population. Cerebral arteries on the brain base of 267 adult cadavers of both genders and varying age and causes of death were dissected. The images of the PCoA in 190 fetuses were also reviewed. ID of the PCoA was defined as a funnel shaped beginning of different width from ICA, wherein PCoA continues from ID apex to the posterior cerebral artery. There were no cases of ID in fetuses. ID and aneurysms of the PCoA were found in 6/267 or 2.2% and 3/267 or 1.12% of adults, respectively. Unilaterally, they existed on the left side and, frequently, in male cases aging 70 years and older, that had died without cerebral cause. Bilaterally, ID was found in 2/6 cases. There was only one case of ID and aneurysm of the PCoA, but from the ID. We are of the opinion that ID of the PCoA only develops postnatally and probably is due to the influence of hemodynamic factors or hypertension. PMID:25458180

Vlajkovi?, Slobodan; Vasovi?, Ljiljana; Trandafilovi?, Milena; Jovanovi?, Ivan; Ugrenovi?, Sla?ana; Dor?evi?, Gordana

2015-01-01

242

Ophthalmic impairment or higher-order visual deficit? Posterior cortical atrophy: a case report.

A 64-year-old man (GK) was referred to our memory clinic because of progressive memory and concentration problems. His symptoms had started 3 years earlier with gradually increasing visual problems for which no ophthalmologic explanations could be found. Neuropsychological assessment with detailed examination of the visuoperception revealed striking impairments in the higher-order visual functions, leading to a probable diagnosis of posterior cortical atrophy (PCA). The results of magnetic resonance imaging and cerebrospinal fluid examination supported the diagnosis. PCA is considered the posterior variant of Alzheimer's disease that typically presents with problems in visuoperception or, less frequent, apraxia. Despite its clear clinical features, the diagnosis of PCA is often delayed because of the focus on ophthalmologic examination. In this case report, the diagnosis of PCA in a 64-year-old man was not considered until further neuropsychological decay was evident. We argue that screening of higher-order visual functions can significantly contribute to an early diagnosis and treatment of PCA. PMID:23373584

Ruis, Carla; van den Berg, Esther; van Zandvoort, Martine J E; Boshuisen, Kim; Frijns, Catharina J M

2012-01-01

243

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

2001-01-01

244

INTRAOCULAR LENS IMPLANTATION IN PEDIATRIC EYES WITH POSTERIOR LENTIGLOBUS

Purpose To report the outcome of intraocular lens (IOL) implantation in pediatric eyes with posterior lentiglobus. Methods Retrospective chart review of pediatric cataract surgery cases with primary IOL implantation. Results Of 553 eyes that received IOL implantation by the lead author, 364 eyes were identified as having been implanted with an IOL at the time of surgery for a nontraumatic cataract. Nineteen (5.2%) of 364 eyes were diagnosed with posterior lentiglobus. The average age at surgery was 5.8 ± 3.8 years (range, 0.6 to 13.9) years. All eyes had monocular cataract. Gender and ethnic distribution were as follows: male-female ratio, 12:7, and African American–Caucasian ratio, 4:15. A preexisting posterior capsule tear was noted at surgery in eight eyes, six of which presented with leukocoria from white cataracts. Site of IOL implantation was as follows: in-the-bag in 14 and sulcus in five, with optic capture into the anterior and posterior capsulotomy in four of those five. The average postoperative follow-up was 3.7 ± 3.0 years. Median postoperative visual acuity was 20/30, and postoperative strabismus was noted in five eyes. Secondary surgery was required in one eye for visual axis opacification and one eye for lysis of synechiae (diagnosed with postoperative spike in intraocular pressure). No other intraoperative or postoperative complications were observed. Conclusion Posterior lentiglobus causes a progressive unilateral cataract. Spontaneous rupture can result in leukocoria from a total white cataract. IOL implantation with posterior lentiglobus provided a satisfactory outcome in children. PMID:17471338

Wilson, M. Edward; Trivedi, Rupal H.

2006-01-01

245

Estimation of Credit Default Probabilities

Estimation of Default Probabilities is critical to the correct pricing of credit derivatives and determining the appropriate level of reserves to support credit risky activities. One of the approach used in literature to estimate default probabilities is based on the structural Merton (1974) model. However it is well known that such structural models have lim- itations. Firstly, many of the

Rita L. D'Ecclesia; R obert G. Tompkins

246

Training Teachers to Teach Probability

ERIC Educational Resources Information Center

In this paper we analyze the reasons why the teaching of probability is difficult for mathematics teachers, describe the contents needed in the didactical preparation of teachers to teach probability and analyze some examples of activities to carry out this training. These activities take into account the experience at the University of Granada,…

Batanero, Carmen; Godino, Juan D.; Roa, Rafael

2004-01-01

247

The report develops probability-based projections that can be added to local tide-gage trends to estimate future sea level at particular locations. It uses the same models employed by previous assessments of sea level rise. The key coefficients in those models are based on subjective probability distributions supplied by a cross-section of climatologists, oceanographers, and glaciologists.

J. G. Titus; V. K. Narayanan

1995-01-01

248

The report develops probability-based projections that can be added to local tide-gage trends to estimate future sea level at particular locations. It uses the same models employed by previous assessments of sea level rise. The key coefficients in those models are based on subjective probability distributions supplied by a cross-section of climatologists, oceanographers, and glaciologists.

Titus, J.G.; Narayanan, V.K.

1995-10-01

249

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

2013-01-01

250

Ideas that Lead to Probability

NSDL National Science Digital Library

This lesson is designed to introduce students to random numbers and fairness as a precursor to learning about probability. The lesson provides links to discussions and activities related to probability and fairness 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 this one.

2011-01-19

251

Expected utility with lower probabilities

An uncertain and not just risky situation may be modeled using so-called belief functions assigning lower probabilities to subsets of outcomes. In this article we extend the von Neumann-Morgenstern expected utility theory from probability measures to belief functions. We use this theory to characterize uncertainty neutrality and different degrees of uncertainty aversion.

Hans JŘrgen Jacobsen; Birgitte Sloth; TORBEN TRANAES

1994-01-01

252

Infectious crystalline keratopathy predominantly affecting the posterior cornea

A case of infectious crystalline keratopathy that affects mainly the posterior stroma is presented. Crystalline infiltrates presented after multiple epithelial defects and chronic topical steroid use following a penetrating keratoplasty in this patient. His epithelial defects persisted and given the deep location of the crystalline infiltrates, a penetrating keratoplasty was performed again. Slit-lamp photo demonstrates the crystalline plaque. Confocal microscopy also documents the aggregates of crystal-like structures. Histology slides are also presented that show the disruption of the stromal-Descemet interface and the predominance of pathology confined to the posterior stroma which has been documented in the literature as a rare finding. PMID:25197405

Mesiwala, Nisreen K; Chu, Charleen T; Raju, Leela V

2014-01-01

253

Bilateral epididymitis in a child with undiagnosed posterior urethral valves.

Posterior urethral valves are most commonly detected in the early neonatal period, the diagnosis often antenatally suspected from ultrasound findings. Nevertheless, some cases might go undetected and become manifest later in life with lower urinary tract symptoms. We describe the unusual case of a 5-year-old boy with a 2-month history of bladder distension, urinary dribbling, and epididymitis. Cystourethrography revealed posterior urethral valves with reflux into the seminal vesicles, vas deferens, and epididymis, bilaterally. A review of the published data is provided in the context of this unusual presentation pattern. PMID:23477755

Kwong, Justin; Lorenzo, Armando J; DeMaria, Jorge; Braga, Luis H P

2013-07-01

254

Management of Posterior Reversible Syndrome in Preeclamptic Women

Posterior reversible encephalopathy syndrome (PRES) is a neurological syndrome associated with a number of conditions including preeclampsia. It is characterized by seizures, alteration of consciousness, visual disturbances, and symmetric white matter abnormalities, typically in the posterior parietooccipital regions of the cerebral hemispheres, at computed tomography (CT) and magnetic resonance (MRI). We report three new cases of PRES in preeclamptic patients and describe the management of these patients. We present a brief review of other cases in the literature, with particular attention to the anesthetic management. PMID:25506009

Poma, S.; Delmonte, M. P.; Gigliuto, C.; Imberti, R.; Delmonte, M.; Arossa, A.; Iotti, G. A.

2014-01-01

255

Posterior Reversible Encephalopathy Syndrome Presenting as Opsoclonus-Myoclonus

Opsoclonus-myoclonus may be caused by various neurological conditions and toxic-metabolic states, but typically occurs as a parainfectious or paraneoplastic manifestation. The development of opsoclonus-myo-clonus has been variably attributed to lesions in the pons or cerebellum. Herein the authors describe a case of opsoclonus-myoclonus due to posterior reversible encephalopathy syndrome in which magnetic resonance imaging revealed lesions in the region of the cerebellar dentate nuclei. Clinical and radiological resolution of the opsoclonus-myoclonus and of the posterior reversible encephalopathy syndrome followed antihyperten-sive therapy. PMID:23125471

Boland, Torrey; Strause, Jamie; Hu, Myra; Santamaria, Dolores; Liang, Tsao-Wei; Kremens, Daniel; Sergott, Robert; Moussouttas, Michael

2012-01-01

256

The Posterior metric and the Goodness of Gibbsianness for transforms of Gibbs measures

We present a general method to derive continuity estimates for conditional probabilities of general (possibly continuous) spin models sub jected to local transformations. Such systems arise in the study of a stochastic time-evolution of Gibbs measures or as noisy observations. We exhibit the minimal necessary structure for such double-layer systems. Assuming no a priori metric on the local state spaces, we define the posterior metric on the local image space. We show that it allows in a natural way to divide the local part of the continuity estimates from the spatial part (which is treated by Dobrushin uniqueness here). We show in the concrete example of the time evolution of rotators on the q-1 dimensional sphere how this method can be used to obtain estimates in terms of the familiar Euclidean metric.

C. Kuelske; A. A. Opoku

2007-11-23

257

Estimation of a Benchmark Dose in the Presence or Absence of Hormesis Using Posterior Averaging.

U.S. Environment Protection Agency benchmark doses for dichotomous cancer responses are often estimated using a multistage model based on a monotonic dose-response assumption. To account for model uncertainty in the estimation process, several model averaging methods have been proposed for risk assessment. In this article, we extend the usual parameter space in the multistage model for monotonicity to allow for the possibility of a hormetic dose-response relationship. Bayesian model averaging is used to estimate the benchmark dose and to provide posterior probabilities for monotonicity versus hormesis. Simulation studies show that the newly proposed method provides robust point and interval estimation of a benchmark dose in the presence or absence of hormesis. We also apply the method to two data sets on carcinogenic response of rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin. PMID:25384940

Kim, Steven B; Bartell, Scott M; Gillen, Daniel L

2014-11-10

258

summary Haplotype analysis is important for mapping traits. Recently, methods for estimating haplotype frequencies from genotypes of unrelated individuals based on the expectation-maximization (EM) algorithm have been developed. Our program estimates haplotype frequencies in the population and determines the posterior probability distribution of diplotype configuration (diplotype distribution) for each subject based on the estimated haplotype frequencies. Samples from three ethnic

Y. KITAMURA; M. MORIGUCHI; H. KANEKO; H. MORISAKI; T. MORISAKI; K. TOYAMA; N. KAMATANI

2002-01-01

259

Purpose To compare the development of posterior capsule opacification (PCO) for idiopathic epi-retinal membrane cases between 20- and 23-gauge phacovitrectomy. Methods Cataract surgery of phacoemulsification with the SA60AT implantation and 20- or 23-gauge vitrectomy was performed for 20 patients in both groups. Cataract surgery alone was performed for 50 patients as the control. The PCO density values were measured using Scheimpflug video photography at 1 week, 1, 3, 6, 12, 18, and 24 months after surgery. The number of eyes that required Nd:YAG laser capsulotomy was also examined. Results The mean PCO value in the 20-gauge phacovitrectomy group increased significantly with time (P<0.001), whereas those in the 23-gauge phacovitrectomy group and the cataract surgery group did not show any significant change. Furthermore, the PCO value in the 20-gauge phacovitrectomy group was significantly greater than that in the 23-gauge phacovitrectomy group at 6, 12, 18 (P<0.05), and 24 months (P<0.01) after surgery. The PCO value in the 23-gauge phacovitrectomy group was significantly greater than that in the cataract surgery group 24 months after surgery (P<0.05). The rate of capsulotomy in the 20-gauge phacovitrectomy group was significantly higher than that in the cataract surgery group (P=0.007), whereas there was no significant difference between the 23-gauge phacovitrectomy group and the cataract surgery group. Conclusion PCO rate in eyes with the 23-gauge phacovitrectomy was lower than in those with the 20-gauge phacovitrectomy, and PCO rate even in the 23-gauge phacovitrectomy was higher than in those with cataract surgery. PMID:23018664

Iwase, T; Oveson, B C; Nishi, Y

2012-01-01

260

On quantum vs. classical probability

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.

Rau, Jochen [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)], E-mail: jochen.rau@q-info.org

2009-12-15

261

Percutaneous fetal cystoscopy and endoscopic fulguration of posterior urethral valves

Percutaneous fetal cystoscopy was performed in a male fetus with ultrasonographic evidence of lower urinary tract obstruction at 19 weeks of gestation. The diagnosis of posterior urethral valves was confirmed. Percutaneous endoscopic fulguration of the valves was successfully performed at 22 weeks of gestation, and urethral patency was established. This case illustrates the feasibility of performing diagnostic and therapeutic endoscopic

Rubén A. Quintero; Roderick Hume; Craig Msith; Mark P. Johnson; David B. Cotton; Roberto Romero; Mark I. Evans

1995-01-01

262

Posterior inferior cerebellar artery aneurysm in the fourth ventricle

We report a patient with a ruptured aneurysm of the choroidal branch of the right posterior inferior cerebellar artery (PICA), lying in and causing an isolated haemorrhage in the fourth ventricle. MRI on the first day after bleeding revealed an abnormal vessel in the fourth ventricle, which was surrounded by a mass of intermediate signal on T1- and T2-weighted images.

H. Urbach; B. Meyer; C. Cedzich; L. Solymosi

1995-01-01

263

Spectrum of the Posterior Inferior Cerebellar Artery Territory Infarcts

Background and Purpose: The clinical, etiological and stroke mechanisms are defined well before but the detailed clinical and etiologic mechanisms regarding to all clinical spectrum of posterior inferior cerebellar artery (PICA) infarcts were not systematically studied by diffusion-weighted imaging (DWI). Methods: Seventy-four patients with PICA territory ischemic lesion proved by DWI with decreased apparent diffusion coefficient and FLAIR (fluid attenuation

Emre Kumral; Ceyla Ataç; Nilgün Yünten

2005-01-01

264

Modern posterior screw techniques in the pediatric cervical spine

Treatment of children with cervical spine disorders requiring fusion is a challenging endeavor for a variety of reasons. The size of the patients, the corresponding abnormal bony anatomy, the inherent ligamentous laxity of children, and the relative rarity of the disorders all play a part in difficulty of treatment. The benefits of modern posterior cervical instrumentation in children, defined as rigid screw-rod systems, have been shown to be many including: improved arthrodesis rates, diminished times in halo-vest immobilization, and improved reduction of deformities. The anatomy of children and the corresponding pathology seen frequently is at the upper cervical spine and craniocervical junction given the relatively large head size of children and the horizontal facets at these regions predisposing them to instability or deformity. Posterior screw fixation, while challenging, allows for a rigid base to allow for fusion in these upper cervical areas which are predisposed to pseudarthrosis with non-rigid fixation. A thorough understanding of the anatomy of the cervical spine, the morphology of the cervical spine, and the available screw options is paramount for placing posterior cervical screws in children. The purpose of this review is to discuss both the anatomical and clinical descriptions related to posterior screw placement in the cervical spine in children. PMID:24829871

Hedequist, Daniel J

2014-01-01

265

Cadherin-mediated adhesion regulates posterior body formation

BACKGROUND: The anterior-posterior axis of the vertebrate embryo undergoes a dramatic elongation during early development. Convergence and extension of the mesoderm, occurring during gastrulation, initiates the narrowing and lengthening of the embryo. However the lengthening of the axis continues during post-gastrula stages in the tailbud region, and is thought to involve convergent extension movements as well as other cell behaviors

Michael J Harrington; Elim Hong; Oluwafoyinsa Fasanmi; Rachel Brewster

2007-01-01

266

Secondary posterior chamber intraocular lens implantation in children

Background: Primary intraocular lens (IOL) implantation after cataract aspiration is a widely accepted means of correcting pediatric aphakia. However, little is available in the literature on secondary IOL implantation in children. We present our experience over the past 6 years. Methods: The charts of 57 aphakic children (61 eyes) who underwent secondary posterior chamber IOL implantation between January 1989 and

Abdulaziz H. Awad; Paul B. Mullaney; Abdulrahman Al-Hamad; David Wheeler; Saleh Al-Mesfer; Johan Zwaan

1998-01-01

267

Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol

Blood Vessels of the Fetal Pig Dissection Posterior Vessels Protocol: 1. The blood vessels membrane is the peritoneum, the blood vessels are said to be retroperitoneal). In order to see the blood that supplies the stomach, liver and spleen with blood. This is the celiac artery. c. Just below where

Loughry, Jim

268

Cerebral vasomotor reactivity monitoring in posterior reversible encephalopathy syndrome

A 25-year-old woman was admitted for vomiting, hypertension and seizures. Magnetic resonance imaging was compatible with posterior reversible encephalopathy syndrome and a transcranial Doppler/vasomotor reactivity study (TCD/VMR) demonstrated loss of vasomotor reactivity. The clinical recovery was concomitant to improvement in the TCD/VMR. PMID:22736754

Forteza, Alejandro; Echeverria, Yosdely; Haussen, Diogo C; Gutierrez, Jose; Wiley, Elka; De Gusmao, Caludio

2010-01-01

269

Cytoarchitecture and Probabilistic Maps of the Human Posterior Insular Cortex

The human posterior insula was shown to respond to a wide variety of stimulation paradigms (e.g. pain, somatosensory, or auditory processing) in functional imaging experiments. Although various anatomical maps of this region have been published over the last century, these schemes show variable results. Moreover, none can directly be integrated with functional imaging data. Hence, our current knowledge about the structure–function relationships in this region remains limited. We therefore remapped the posterior part of the human insular cortex in 10 postmortem brains using an observer-independent approach. This analysis revealed the existence of 3 cytoarchitectonically distinct areas in the posterior insula. The examined brains were then 3D reconstructed and spatially normalized to the Montreal Neurological Institute single-subject template. Probabilistic maps for each area were calculated by superimposing the individual delineations, and a cytoarchitectonic summary map was computed to chart the regional architectonic organization. These maps can be used to identify the anatomical correlates of functional activations observed in neuroimaging studies and to understand the microstructural correlates of the functional segregation of the human posterior insula. PMID:19822572

Eickhoff, Simon B.; Schleicher, Axel; Hoemke, Lars; Zilles, Karl; Amunts, Katrin

2010-01-01

270

Delayed posterior circulation insufficiency in pediatric moyamoya disease.

Approximately 30% of patients with moyamoya disease (MMD) have presented with involvement of the posterior circulation, mainly the posterior cerebral artery (PCA). Diagnosis of delayed progression of PCA stenosis in MMD may be difficult due to the diversity in clinical features. The goal of this study was to evaluate pediatric MMD patients with delayed PCA involvement after completion of revascularization of the anterior circulation. Forty-one pediatric MMD patients who underwent revascularization of the PCA territory due to delayed posterior circulation insufficiency MMD from 2006 to 2011 were retrospectively reviewed. The average interval between the initial operation and the occipital artery (OA) procedure was 5.0 years. Common symptoms were headaches and transient visual symptoms. The decision to operate was made based on a combination of diagnostic tools. The results obtained with perfusion MRI, SPECT, MR angiography, and EEG supported posterior circulation insufficiency in 78, 41, 73, and 71% of patients, respectively. Encephaloduroarteriosynangiosis (EDAS) using the OA was performed in 15 patients, and 26 patients received multiple burr hole trephination of the occipital area. All patients showed clinical improvement. Clinicians should be aware of the possibility of delayed involvement of the PCA in pediatric MMD patients. The clinical decision regarding treatment should be based on a combination of symptomatology and the results obtained with various tools to assess whether the blood flow in the PCA territory is insufficient. Surgical treatment using indirect revascularization appears to be effective for patients with delayed PCA involvement. PMID:25212285

Lee, Ji Yeoun; Choi, Young-Hun; Cheon, Jung-Eun; Paeng, Jin Chul; Ryu, Hye Won; Kim, Ki Joong; Phi, Ji Hoon; Wang, Kyu-Chang; Cho, Byung-Kyu; Chae, Jong-Hee; Kim, Seung-Ki

2014-12-01

271

Aneurysms of the posterior communicating artery and oculomotor paresis

One hundred and seventy-four patients with a posterior communicating aneurysm were seen over a 21 year period. There was a ratio of four females to one male and women were on average five years older. Fifty-nine (34%) had an oculomotor paresis. This group had up to four attacks of localized headache, large multiloculated aneurysms, and a greater time lapse from

S. R. Soni

1974-01-01

272

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

2010-08-01

273

Rib bone graft for posterior spinal fusion in children.

Treatment of columnar instability in children with conventional fusion procedures may preclude normal growth and cause dysfunction and pain due to malalignment or reduced mobility. To achieve normal growth, we have treated spinal instability in 7 children with posterior fusion, using bilateral rib transplants secured by horizontal laminar cerclages. Solid fusion was obtained and no serious complications occurred. PMID:12553523

Berg-Johnsen, Jon; Magnaes, Bjřrn

2002-12-01

274

Evidential segmentation of microscopic color images with pixel classification posterior

Evidential segmentation of microscopic color images with pixel classification posterior-mail:{christophe.charrier,gilles.lebrun,olivier.lezoray}@unicaen.fr Abstract-- A tool for diagnosis assistance by automatic segmentation of microscopic cellular images classifications. Index Terms-- Segmentation, microscopic cellular images, Classification, Dempster

Lezoray, Olivier

275

Results of Singular Neurectomy in the Posterior Ampullary Recess

Objective: To determine the effect on hearing and balance symptoms following singular neurectomy (SN) for benign paroxysmal positional vertigo (BPPV) in the ampullary recess of the posterior semicircular canal. Research Design: The charts of 242 patients with chronic disabling BPPV who were treated with SN over a 29-year period (1972–2001) were reviewed. The results on relief of BPPV and hearing

Richard R. Gacek; Mark R. Gacek

2002-01-01

276

Pathological localization of so-called posterior canal BPPV

ObjectiveBased on the hypothesis that the origin of nystagmus is from the posterior canal (PC), the nystagmus in the head hanging and sitting position should be mirror images. To clarify the anatomical origin of positioning nystagmus in BPPV patients, we analyzed the positioning nystagmus of benign paroxysmal positioning vertigo (BPPV) patients three-dimensionally.

Toshiaki Yagi; Yasuo Koizumi; Maki Kimura; Mio Aoyagi

2006-01-01

277

Atrial natriuretic factor-like activity in rat posterior pituitary

The presence of a biologically active peptide: Atrial Natriuretic Factor (ANF) has been demonstrated in rat and human circulation and ANF is considered now as a new hormone. ANF may be involved in body fluid regulation. A very sensitive radioimmunoassay for rat ANF allowed the authors to search for immunoreactive ANF (IR-ANF) in rat posterior pituitary. Serial dilutions of homogenates of rat posterior pituitary showed a good parallelism with a reference curve in a radioimmunoassay system. The IR-ANF was extracted from rat posterior pituitary homogenates by activated Vycor glass beads. The lyophilized extract was purified by HPLC on C/sub 18/ ..mu.. Bondapak column. The HPLC yielded two IR-ANF peaks. Both isolated ANF-like material showed biological activity. The IR-ANF eluted with 33% acetonitrile, inhibited ACTH-stimulated aldosterone secretion with a similar potency as synthetic (Arg 101 - Tyr 126) ANF (0.7 x 10/sup -10/M). A much less potent ANF-like material was found in the second peak eluted with 36% acetonitrile. They conclude that ANF-like material is present in rat posterior pituitary and this suggest a possible role in ANF on AVP secretion directly in situ.

Gutkowska, J.; Debinski, W.; Racz, K.; Thibault, G.; Garcia, R.; Kuchel, O.; Genest, J.; Cantin, M.

1986-03-05

278

Neurophysins and Posterior Pituitary Hormones in the Suiformes

The neurophysins are proteins that bind the posterior pituitary hormones within the neurosecretory vesicles of the vertebrate neurohypophysis. In the pig, immunofluorescence localization of porcine neurophysin II suggests that this protein is stored with [8-lysine]-vasopressin (LVP). Gel electrophoresis and immunodiffusion of neurohypophysial proteins from two other Suiformes species, the hippopotamus and warthog, hitherto thought to contain LVP, reveal that the

L. O. Uttenthal; D. B. Hope

1972-01-01

279

On Posterior Consistency in Selection Models Jaeyong Lee

and Martin (1974), Patil and Rao (1977), Sun and Woodroofe (1997), and Lee and Berger (1999)), metaOn Posterior Consistency in Selection Models Jaeyong Lee National Institute of Statistical Sciences (1977)), and astronomy (Sun and Woodroofe (1997)). The weight function is usually nondecreasing

West, Mike

280

The Probabilities of Unique Events

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

2012-01-01

281

Dinosaurs, Dinosaur Eggs, and Probability.

ERIC Educational Resources Information Center

Outlines several recommendations for teaching probability in the secondary school. Offers an activity that employs simulation by hand and using a programmable calculator in which geometry, analytical geometry, and discrete mathematics are explored. (KHR)

Teppo, Anne R.; Hodgson, Ted

2001-01-01

282

NSDL National Science Digital Library

The QM Probability 2D program displays the time evolution of the two-dimensional probability density using color to represent its magnitude. The default wave function is a two-state superposition in the x (nx = 1,2) and y dimension (ny = 3,4) state in an infinite square well. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Probability 2D is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_probability_2d.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

Christian, Wolfgang

2008-05-20

283

Axial Spondylectomy and Circumferential Reconstruction via a Posterior Approach

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.

2013-01-01

284

Joint probabilities and quantum cognition

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

2012-06-26

285

Joint probabilities and quantum cognition

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)

2012-12-18

286

Incompatible Stochastic Processes and Complex Probabilities

NASA Technical Reports Server (NTRS)

The definition of conditional probabilities is based upon the existence of a joint probability. However, a reconstruction of the joint probability from given conditional probabilities imposes certain constraints upon the latter, so that if several conditional probabilities are chosen arbitrarily, the corresponding joint probability may not exist.

Zak, Michail

1997-01-01

287

NASA Astrophysics Data System (ADS)

Formal and informal Bayesian approaches are increasingly being used to treat forcing, model structural, parameter and calibration data uncertainty, and summarize hydrologic prediction uncertainty. This requires posterior sampling methods that approximate the (evolving) posterior distribution. We recently introduced the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, an adaptive Markov Chain Monte Carlo (MCMC) method that is especially designed to solve complex, high-dimensional and multimodal posterior probability density functions. The method runs multiple chains in parallel, and maintains detailed balance and ergodicity. Here, I present the latest algorithmic developments, and introduce a discrete sampling variant of DREAM that samples the parameter space at fixed points. The development of this new code, DREAM(D), has been inspired by the existing class of integer optimization problems, and emerging class of experimental design problems. Such non-continuous parameter estimation problems are of considerable theoretical and practical interest. The theory developed herein is applicable to DREAM(ZS) (Vrugt et al., 2011) and MT-DREAM(ZS) (Laloy and Vrugt, 2011) as well. Two case studies involving a sudoku puzzle and rainfall - runoff model calibration problem are used to illustrate DREAM(D).

Vrugt, J. A.

2011-04-01

288

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

2014-04-01

289

In this paper, we continue to explore the consistence and usability of Probability Bracket Notation (PBN) proposed in our previous articles. After a brief review of PBN with dimensional analysis, we investigate probability spaces in terms of PBN by introducing probability spaces associated with random variables (R.V) or associated with stochastic processes (S.P). Next, we express several important properties of conditional expectation (CE) and some their proofs in PBN. Then, we introduce martingales based on sequence of R.V or based on filtration in PBN. In the process, we see PBN can be used to investigate some probability problems, which otherwise might need explicit usage of Measure theory. Whenever applicable, we use dimensional analysis to validate our formulas and use graphs for visualization of concepts in PBN. We hope this study shows that PBN, stimulated by and adapted from Dirac notation in Quantum Mechanics (QM), may have the potential to be a useful tool in probability modeling, at least for those who are already familiar with Dirac notation in QM.

Xing M. Wang

2009-10-15

290

Precise measurement of the gamma-ray emission probabilities of 38Cl

Accurate gamma-ray emission probabilities for 38Cl have been determined from measurements of the disintegration rate and gamma-ray intensities. Recommended gamma-ray emission probabilities within the literature have systematic uncertainties of 4.8%, whereas the current measurements gave uncertainties less than 1%. The absolute emission probabilities of the 1642.7 and 2167.7 keV gamma rays were 0.3338 ± 0.0032 and 0.4477 ± 0.0031, respectively,

Hiroshi Miyahara; Atsushi Yoshida; Gatot Wurdiyanto; Kei Hara; Katsuo Yanagida; Chizuo Mori

1996-01-01

291

What are the risks, benefits, alternatives, and pitfalls for operating on cervical ossification of the posterior longitudinal ligament (OPLL)? To successfully diagnose OPLL, it is important to obtain Magnetic Resonance Images (MR). These studies, particularly the T2 weighted images, provide the best soft-tissue documentation of cord/root compression and intrinsic cord abnormalities (e.g. edema vs. myelomalacia) on sagittal, axial, and coronal views. Obtaining Computed Tomographic (CT) scans is also critical as they best demonstrate early OPLL, or hypertrophied posterior longitudinal ligament (HPLL: hypo-isodense with punctate ossification) or classic (frankly ossified) OPLL (hyperdense). Furthermore, CT scans reveal the “single layer” and “double layer” signs indicative of OPLL penetrating the dura. Documenting the full extent of OPLL with both MR and CT dictates whether anterior, posterior, or circumferential surgery is warranted. An adequate cervical lordosis allows for posterior cervical approaches (e.g. lamionplasty, laminectomy/fusion), which may facilitate addressing multiple levels while avoiding the risks of anterior procedures. However, without lordosis and with significant kyphosis, anterior surgery may be indicated. Rarely, this requires single/multilevel anterior cervical diskectomy/fusion (ACDF), as this approach typically fails to address retrovertebral OPLL; single or multilevel corpectomies are usually warranted. In short, successful OPLL surgery relies on careful patient selection (e.g. assess comorbidities), accurate MR/CT documentation of OPLL, and limiting the pros, cons, and complications of these complex procedures by choosing the optimal surgical approach. Performing OPLL surgery requires stringent anesthetic (awake intubation/positioning) and also the following intraoperative monitoring protocols: Somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), and electromyography (EMG). PMID:24843819

Epstein, Nancy E.

2014-01-01

292

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

2013-05-01

293

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

2012-06-01

294

Posterior reversible encephalopathy syndrome in a adult female.

Posterior reversible encephalopathy syndrome is a clinico-neuroradiologic diagnosis, with rapidly evolving neurologic condition, characterized by headache, confusion, altered mental status, seizures, cortical blindness, lethargy, stupor, and occasionally, focal neurological signs accompanied by a typical computed tomography or magnetic resonance imaging pattern. With early recognition and treatment, complete resolution of symptoms occurs. Typical imaging findings characteristically involve the white matter bilaterally in the parieto-occipital regions. Atypical imaging finding of contrast enhancement of lesion can occur, but is less common. A 20-year-old primiparous lady presented with posterior reversible encephalopathy syndrome. To the best of our knowledge, this is the first documented case in Nigeria. This case-report highlights the importance of recognizing the salient imaging features in this lethal but reversible entity with prompt management. PMID:24923375

Oyinloye, O I; Adesiyun, O A M; Atobatele, M O; Fawole, A A

2014-01-01

295

Reversible posterior leukoencephalopathy syndrome in pregnancy: a case report.

Posterior reversible encephalopathy syndrome (PRES), is an acute, neurotoxic state. It is a very rare clinico-neuroradiological entity, and it is a complication of multiple clinical conditions. The association of PRES with toxemia in pregnancy is established. In this article, the authors discuss the case of a 22-year-old woman, gravida 1, 36-week pregnant, with extensive, bilateral white matter hypodensity, predominantly involving the parieto-occipital lobes region. These changes were highly suggestive of posterior reversible encephalopathy. This case report demonstrates that early treatment with control of blood pressure seizures can reverse this condition and also prevent progression to an irreversible damage, thus emphasizing the need for early diagnosis and treatment. PMID:24597270

Patacchiola, F; Franchi, V; Di Febbo, G; Carta, A; Carta, G

2013-01-01

296

Posterior and anterior components of force during bite loading.

Late anterior crowding of teeth has been associated with the anterior component of force (ACF) developed during biting. Possible physiologic mechanisms countering ACF, including the presence of a posterior component of force (PCF), are hypothesized. In this self-controlled study, 60 subjects aged 27.05+/-3.9 years were examined for ACF and PCF that were calculated as the change in tightness of a mandibular dental contact points from non-biting to biting state. Both ACF and PCF were found to develop simultaneously. However, the PCF was 4-7 folds smaller than the ACF (p<0.001). The ACF progressively declined by 10-20 folds (p<0.001) from the posterior to anterior dentition. The lateral incisor-canine contact point had the greatest ACF decline (63-74%). ACF effect on the anterior dentition is counteracted by a protective mechanism consisted of PCF, progressive dissipation of ACF, and canine blockage. PMID:16697387

Vardimon, A D; Beckmann, S; Shpack, N; Sarne, O; Brosh, T

2007-01-01

297

Cysts in the posterior triangle of the neck in adults.

Cystic lesions of the posterior triangle are a pathologic entity whose diagnosis is made in the first two years of life. Its presentation in adulthood is an incidental finding and the differential diagnosis includes cystic lymphangioma, lymphatic metastasis of thyroid cancer and branchial cyst. Often with the finding of a cervical lump, FNA is made before diagnostic imaging is performed, however, this procedure is not always advisable. We reviewed the cases of patients who came last year to our department with a cystic mass in this location and correlating the imaging findings with pathologic specimen. We show characteristic findings of these lesions in order to make an early diagnosis and thus to get the approach and treatment appropriate of adult patients with a cystic lesion in the posterior cervical triangle. PMID:24846559

Brea-Álvarez, Beatriz; Roldán-Hidalgo, Amaya

2014-05-17

298

Accurate and Reliable Gait Cycle Detection in Parkinson's Disease.

There is a growing interest in the use of Inertial Measurement Unit (IMU)-based systems that employ gyroscopes for gait analysis. We describe an improved IMU-based gait analysis processing method that uses gyroscope angular rate reversal to identify the start of each gait cycle during walking. In validation tests with six subjects with Parkinson disease (PD), including those with severe shuffling gait patterns, and seven controls, the probability of True-Positive event detection and False-Positive event detection was 100% and 0%, respectively. Stride time validation tests using high-speed cameras yielded a standard deviation of 6.6 ms for controls and 11.8 ms for those with PD. These data demonstrate that the use of our angular rate reversal algorithm leads to improvements over previous gyroscope-based gait analysis systems. Highly accurate and reliable stride time measurements enabled us to detect subtle changes in stride time variability following a Parkinson's exercise class. We found unacceptable measurement accuracy for stride length when using Aminian and colleague's gyro-based biomechanical algorithm, with errors as high as 30% in PD subjects. An alternative method, using synchronized infrared timing gates to measure velocity, combined with accurate mean stride time from our angular rate reversal algorithm, more accurately calculates mean stride length. PMID:24158491

Hundza, Sandra; Hook, William; Harris, Christopher; Mahajan, Sunny; Leslie, Paul; Spani, Carl; Spalteholz, Leonhard; Birch, Benjamin; Commandeur, Drew; Livingston, Nigel

2013-10-22

299

Anterior and posterior centers jointly regulate Bombyx embryo body segmentation.

Insect embryo segmentation is largely divided into long and short germ types. In the long germ type, each segment primordium is represented on a large embryonic rudiment of the blastoderm, and segmental patterning occurs nearly simultaneously in the syncytium. In the short germ type, however, only anterior segments are represented in the small embryonic rudiment, usually located on the egg posterior, and the rest of the segments are added sequentially from the posterior growth zone in a cellular context. The long germ type is thought to have evolved from the short germ type. It is proposed that this transition, which appears to have occurred multiple times over the course of evolution, was realized through the acquisition of a localized anterior instruction center. Here, I examined the early segmentation process in the silkmoth Bombyx mori, a lepidopteran insect, in which the mechanisms of anterior-posterior (AP) axis formation have not been well analyzed. In this insect, both the long germ and short germ features have been reported. The mRNAs for two key genes involved in insect AP axis formation, orthodenticle (Bm-otd) and caudal (Bm-cad), are localized maternally in the germ anlage, where they act as anterior and posterior instruction centers, respectively. RNAi studies indicate that, while Bm-cad affects the formation of all the even skipped (Bm-eve) stripes, there is also anterior Bm-eve stripe formation activity that involves Bm-otd. Thus, there is redundancy in Bm-eve stripe formation activity that must be coordinated. Some genetic interactions, identified either experimentally or hypothetically, are also introduced, which might enable robust AP formation in this organism. PMID:22975228

Nakao, Hajime

2012-11-15

300

Foraminotomia cervical posterior en el tratamiento de conflictos foraminales

Introducción: La foraminomotima cervical posterior es un procedimiento utilizado para la descompresion radicular por via posterior y constituye una alternativa a la via clásica anterior. En este trabajo evaluamos nuestra serie de pacientes tratados por esta via. Método: Desde enero de 2008 a diciembre de 2011, 17 pacientes (18 foraminotomías) fueron operados por presentar cervicobraquialgia a causa de un conflicto foraminal, realizando un foraminotomía cervical posterior. Los pacientes fueron evaluados en el postoperatorio inmediato, al mes y a los 3 meses de la cirugía. Los parámetros para valorar los resultados fueron la Escala Análoga del Dolor (VAS), la Neck Disability Index y los criterios de Odom. Resultados: El dolor radicular por conflicto foraminal secundario a hernia de disco cervical fue el síntoma y la patología predominante. El nivel más afectado fue C5-C6. La resolución completa del dolor radicular se observó en casi todos los pacientes. La VAS preoperatoria en promedio fue de 8.8 (mínimo 8 – máximo 10), con una franca mejoría en todos los casos (0.4 en el último control). La media en la Neck Disability Index al inicio fue de 35.3 (mínimo 32 – máximo 45), con una evolución favorable en la evaluación final (0.6). Los Criterios de Odom para la evaluación de pacientes operados de columna cervical fueron satisfactorios con un promedio de 1.17. Se observaron complicaciones en 4 pacientes (23%), todas tuvieron una evolución favorable. No hubo infecciones, discitis ni empeoramiento de los síntomas preexistentes en ningún paciente. Conclusión: La foraminotomía cervical posterior es un procedimiento efectivo para el tratamiento del dolor radicular en los conflictos foraminales PMID:23596556

Campero, Álvaro; Barrera, Ramiro; Ajler, Pablo

2012-01-01

301

Posterior Covariance vs. Analysis Error Covariance in Data Assimilation

-1 b b + R ()C V -1 o o, (11) where H(, ~) = V -1 b + R ()C V -1 o CR( ~). (12) F.-X. Le Dimet (INRIA) - t - (F ()) = -C V -1 o C, t=T = 0, (14) H(, ~)v = V -1 b v - |t=0. (15) The operator H(, ~) is neithPosterior Covariance vs. Analysis Error Covariance in Data Assimilation F.-X. Le Dimet(1), I

Boyer, Edmond

302

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

2014-10-01

303

Superior Labral Anterior Posterior Lesions of the Shoulder

Superior labrum anterior and posterior (SLAP) lesion is of fairly recent description and its understanding is rapidly evolving. Its incidence and need for surgical treatment has increased exponentially in line with the increase in shoulder arthroscopies. It is of particular importance in the elite over head athlete and the young. A range of arthroscopic techniques and devices have been described with good functional results. The ability to return to pre injury level of sports remains a concern. PMID:24082975

Malal, Joby Jacob George; Khan, Yousaf; Farrar, Graville; Waseem, Mohammed

2013-01-01

304

Posterior-stabilized versus cruciate-retaining total knee arthroplasty

A prospective, randomized, double-blind trial was carried out to compare cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasties (TKAs). A total of 40 knees were randomized to receive either a NexGen CR (Zimmer, Warsaw, IN) or a Legacy PS (Zimmer, Warsaw, IN) TKA. All knees were implanted with identical surgical technique, making sure to balance precisely the flexion-extension gaps before

Michael Tanzer; Karen Smith; Stephen Burnett

2002-01-01

305

Comprehensive gait analysis in posterior-stabilized knee arthroplasty

Sixteen patients implanted with a posterior-stabilized prosthesis (Insall-Burstein PS II, Zimmer, Warsaw, IN) and 32 age-matched control subjects were evaluated by isokinetic muscle testing and comprehensive gait analysis at a mean 46 months following the index arthroplasty. The contralateral knee was normal in 13 patients and an asymptomatic total knee arthroplasty in 3 patients. No significant differences (P > .05)

Stephen A. Wilson; Peter D. McCann; Robert S. Gotlin; H. K. Ramakrishnan; Mary E. Wootten; John N. Insall

1996-01-01

306

Experience with intrawound vancomycin powder for posterior cervical fusion surgery.

OBJECT Recent studies have reported that the local delivery of vancomycin powder is associated with a decrease in spinal surgical site infection. This retrospective cohort study compares posterior cervical fusion cases before and after the routine application of spinal vancomycin powder to evaluate the ability of local vancomycin powder to prevent deep wound infection after posterior cervical spinal fusion. METHODS Posterior cervical fusion spinal surgeries performed at a single institution were reviewed from January 2011 to July 2013. Each cohort's baseline characteristics, operative data, and rates of wound infection were compared. Associations between infection and vancomycin powder, with and without propensity score adjustment for risk factors, were determined using logistic regression. RESULTS A total of 289 patients (174 untreated and 115 treated with vancomycin powder) were included in the study. The cohorts were similar in terms of baseline and operative variables. No significant change in deep wound infection rate was seen between the control group (6.9%) and intervention group (5.2%, p = 0.563). Logistic regression, with and without propensity score adjustment, demonstrated that the use of vancomycin powder did not impact the development of surgical site infection (OR 0.743 [95% CI 0.270-2.04], p = 0.564) and (OR 0.583 [95% CI 0.198-1.718], p = 0.328), respectively. CONCLUSIONS Within the context of an ongoing debate on the effectiveness of locally administered vancomycin powder, the authors found no significant difference in the incidence of deep wound infection rates after posterior cervical fusion surgery with routine use of locally applied vancomycin powder. Future prospective randomized series are needed to corroborate these results. PMID:25380539

Martin, Joel R; Adogwa, Owoicho; Brown, Christopher R; Kuchibhatla, Maragatha; Bagley, Carlos A; Lad, Shivanand P; Gottfried, Oren N

2014-11-01

307

Axial pain after posterior cervical spine surgery: a systematic review

Posterior operative approach has been the standard treatment for cervical compressive myelopathy, and axial pain after laminoplasty\\u000a or laminectomy as a postoperative complication is now gradually receiving more and more attention. The objective of this study\\u000a was to provide a systematic review of the current understanding of axial pain after cervical laminoplasty and laminectomy,\\u000a and summarize clinical features, influence factors

Shan-Jin Wang; Sheng-Dan Jiang; Lei-Sheng Jiang; Li-Yang Dai

2011-01-01

308

Posterior and anterior components of force during bite loading

Late anterior crowding of teeth has been associated with the anterior component of force (ACF) developed during biting. Possible physiologic mechanisms countering ACF, including the presence of a posterior component of force (PCF), are hypothesized. In this self-controlled study, 60 subjects aged 27.05±3.9 years were examined for ACF and PCF that were calculated as the change in tightness of a

A. D. Vardimon; S. Beckmann; N. Shpack; O. Sarne; T. Brosh

2007-01-01

309

Cadherin-mediated adhesion regulates posterior body formation

Background The anterior-posterior axis of the vertebrate embryo undergoes a dramatic elongation during early development. Convergence and extension of the mesoderm, occurring during gastrulation, initiates the narrowing and lengthening of the embryo. However the lengthening of the axis continues during post-gastrula stages in the tailbud region, and is thought to involve convergent extension movements as well as other cell behaviors specific to posterior regions. Results We demonstrate here, using a semi-dominant N-cadherin allele, that members of the classical cadherin subfamily of cell-cell adhesion molecules are required for tailbud elongation in the zebrafish. In vivo imaging of cell behaviors suggests that the extension of posterior axial mesodermal cells is impaired in embryos that carry the semi-dominant N-cadherin allele. This defect most likely results from a general loss of cell-cell adhesion in the tailbud region. Consistent with these observations, N-cadherin is expressed throughout the tailbud during post-gastrulation stages. In addition, we show that N-cadherin interacts synergistically with vang-like 2, a member of the non-canonical Wnt signaling/planar cell polarity pathway, to mediate tail morphogenesis. Conclusion We provide the first evidence here that N-cadherin and other members of the classical cadherin subfamily function in parallel with the planar cell polarity pathway to shape the posterior axis during post-gastrulation stages. These findings further highlight the central role that adhesion molecules play in the cellular rearrangements that drive morphogenesis in vertebrates and identify classical cadherins as major contributors to tail development. PMID:18045497

Harrington, Michael J; Hong, Elim; Fasanmi, Oluwafoyinsa; Brewster, Rachel

2007-01-01

310

Interference of probabilities in dynamics

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, E-mail: michail.zak@gmail.com [Jet Propulsion Laboratory California Institute of Technology, Pasadena, CA 91109 (United States)

2014-08-15

311

Mitomycin against posterior capsular opacification: an experimental study in rabbits.

AIMS/BACKGROUND: Posterior capsular opacification is the most common postoperative complication of extracapsular cataract surgery. The purpose of this study was to attempt to inhibit this secondary cataract formation by using mitomycin (an antimitotic drug). METHODS: A solution containing mitomycin was used to perform hydrodissection (with a 5 minute pause) during extracapsular lens extraction in rabbits. This way of administration was chosen to reduce as much as possible drug diffusion into the anterior chamber. Heparin was added to the irrigating solution to avoid fibrin formation. Its ability to prevent posterior cataract opacification was also evaluated at the end of the study. The animals were sacrificed 4 or 6 months after surgery. Grading concerning two aspects of secondary cataract (proliferation and fibrosis) was obtained on gross examination. Histological analysis was subsequently performed. RESULTS: This study demonstrated that mitomycin has a significant inhibitory effect on secondary cataract formation (proliferation as well as fibrosis) in rabbits whereas heparin does not seem to have the same effectiveness. CONCLUSION: This work is a preliminary study concerning the use of mitomycin for prevention of posterior capsular opacification. It has proved its effectiveness in rabbits but more in depth studies are still necessary before its application in humans. Images PMID:9059276

Haus, C M; Galand, A L

1996-01-01

312

Intensity-Modulated Arc Therapy for Pediatric Posterior Fossa Tumors

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: chris.beltran@stjude.org [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)

2012-02-01

313

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

1991-06-01

314

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

2010-01-01

315

Clinical, imagiological and etiological spectrum of posterior reversible encephalopathy syndrome.

Objective Analyze the cases of posterior reversible encephalopathy syndrome (PRES) admitted in a Neurology Department during an 8-year period. Method Retrospective observational study in a central hospital in the north of Portugal. Results 14 patients were identified, mean age 52.3 years. Precipitating factors included: eclampsia, isolated arterial hypertension, spinal trauma and autonomic dysreflexia, Guillain-Barré syndrome, sepsis, sarcoidosis and pulmonary cryptococcosis and drugs. Most patients presented posterior-predominant vasogenic edema lesions, however 64.2% presented frontal lesions and in 42.8% cerebellum was involved. Four patients also had acute ischemic lesions and 1 had hemorrhagic lesions. During follow-up 10 patients recovered fully, 2 recovered partially, 1 suffered a recurrence and 2 died in hospital. Conclusion PRES has many etiological factors. The terms posterior and reversible should be revised because PRES frequently involves other brain regions and it is not always reversible. PRES patients may develop life-threatening complications and mortality is not negligible. PMID:25608125

Pereira, P Ricardo; Pinho, Joăo; Rodrigues, Margarida; Rocha, Joăo; Sousa, Filipa; Amorim, José; Ribeiro, Manuel; Rocha, Jaime; Ferreira, Carla

2015-01-01

316

A new donor cornea harvesting technique for posterior lamellar keratoplasty

Aims: To describe a technique for posterior lamellar keratoplasty donor preparation. Methods: In an experimental study eight human donor research corneas were mounted onto an artificial anterior chamber and deep stromal pockets dissected. Four corneas were mounted in the standard endothelial side down orientation and dissected using standard instruments (group 1). Another four corneas were mounted endothelial side up and dissected using a flat spatula (group 2). Trephined lamellar graft thickness was assessed by ultrasound pachymetry. The grafts were also analysed using vital staining of the endothelium and standard histological preparation. Results: Achieved posterior graft thickness was 118 (SD 32) ?m (group 1) and 92 (23) ?m (group 2) (p?=?0.324). Percentage of devitalised endothelial cells was 0.86% (1.48%) (group 1) and 3.9% (2.9%) (group 2) (p?=?0.185). The dissections using both harvesting techniques remained in plane and were smooth. Conclusions: A blunt spatula and endothelium side up orientation on an artificial anterior chamber can be used to create posterior lamellar dissections without compromising endothelial cell number or planarity when compared to standard endothelium side down harvest. PMID:16113357

Suwan-apichon, O; Rizen, M; Reyes, J M G; Herretes, S; Behrens, A; Stark, W J; Chuck, R S

2005-01-01

317

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

2010-01-01

318

NASA Astrophysics Data System (ADS)

We present an approximate calculation of the full Bayesian posterior probability distribution for the local non-Gaussianity parameter fnl from observations of cosmic microwave background anisotropies within the framework of information field theory. The approximation that we introduce allows us to dispense with numerically expensive sampling techniques. We use a novel posterior validation method (DIP test) in cosmology to test the precision of our method. It transfers inaccuracies of the calculated posterior into deviations from a uniform distribution for a specially constructed test quantity. For this procedure we study toy cases that use one- and two-dimensional flat skies, as well as the full spherical sky. We find that we are able to calculate the posterior precisely under a flat-sky approximation, albeit not in the spherical case. We argue that this is most likely due to an insufficient precision of the used numerical implementation of the spherical harmonic transform, which might affect other non-Gaussianity estimators as well. Furthermore, we present how a nonlinear reconstruction of the primordial gravitational potential on the full spherical sky can be obtained in principle. Using the flat-sky approximation, we find deviations for the posterior of fnl from a Gaussian shape that become more significant for larger values of the underlying true fnl. We also perform a comparison to the well-known estimator of Komatsu et al. [Astrophys. J. 634, 14 (2005)] and finally derive the posterior for the local non-Gaussianity parameter gnl as an example of how to extend the introduced formalism to higher orders of non-Gaussianity.

Dorn, Sebastian; Oppermann, Niels; Khatri, Rishi; Selig, Marco; Enßlin, Torsten A.

2013-11-01

319

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.

2008-12-11

320

Management of posterior capsule rupture during phacoemulsification using the dry technique

To manage posterior capsule rupture during phacoemulsification, we use a dry technique in which all procedures are performed without an irrigation\\/aspiration system. The dry technique is characterized by (1) continuous viscoelastic injection instead of fluid irrigation to maintain anterior chamber depth with the posterior capsule and vitreous located posteriorly and (2) static removal of most residual lens material by viscoexpression

Junsuke Akura; Shiro Hatta; Shuzo Kaneda; Mika Ishihara; Kazuki Matsuura; Akihiko Tamai

2001-01-01

321

Objective Synovitis is thought to be a secondary phenomenon in the osteoarthritis (OA) process and the menisci might be triggers of localized synovitis. The aim was to assess the cross-sectional associations of posterior horn meniscal damage with perimeniscal synovitis, and with synovitis posterior to the posterior cruciate ligament (PCL) using contrast enhanced (CE) MRI. Design The Multicenter Osteoarthritis (MOST) Study is a longitudinal observational study of subjects with or at risk for knee OA. Subjects are a subset of MOST who were examined with 1.5 T CE MRI and had semiquantitative synovitis (scored from 0–2 at 11 locations) and meniscal readings (scored with WORMS from 0–4 ) available. Logistic regression was used to assess the association of posterior meniscal damage and perimeniscal synovitis in the same compartment, and between posterior meniscal damage and synovitis posterior to the PCL. Results Three hundred and seventy seven knees were included (mean age 61.1 years ± 6.9, mean BMI 29.6 ± 4.9, 44.3% women). The odds for ipsi-compartmental perimeniscal synovitis were increased for knees with medial posterior horn meniscal damage (adjusted odds ratio [aOR] 2.5, 95% confidence intervals [95% CI] 1.3,4.8), but not for lateral damage (aOR 1.7, 95% CI 0.4,6.6). No positive associations were found for meniscal damage and presence of synovitis posterior to the PCL (aOR 0.9, 95% CI 0.6,1.5). Conclusions Meniscal damage of the posterior horns is associated with ipsi-compartmental perimensical synovitis. No associations were found for posterior horn meniscal damage with synovitis posterior to the PCL, which suggests that synovitis posterior to the PCL is likely to be triggered by different pathomechanisms. PMID:23270763

Roemer, Frank W.; Felson, David T.; Yang, Tianzhong; Niu, Jingbo; Crema, Michel D.; Englund, Martin; Nevitt, Michael C.; Zhang, Yuqing; Lynch, John A.; El Khoury, George Y.; Torner, James; Lewis, Cora E.; Guermazi, Ali

2013-01-01

322

GPS: Geometry, Probability, and Statistics

ERIC Educational Resources Information Center

It might be said that for most occupations there is now less of a need for mathematics than there was say fifty years ago. But, the author argues, geometry, probability, and statistics constitute essential knowledge for everyone. Maybe not the geometry of Euclid, but certainly geometrical ways of thinking that might enable us to describe the world…

Field, Mike

2012-01-01

323

The Axioms of Subjective Probability

This survey recounts contributions to the axiomatic foundations of subjective probability from the pioneering era of Ramsey, de Finetti, Savage, and Koopman to the mid-1980's. It is designed to be accessible to readers who have little prior acquaintance with axiomatics. At the same time, it provides a fairly complete picture of the present state of the measurement-theoretic foundations of subjective

Peter C. Fishburn

1986-01-01

324

Determinants of Default Probability Changes?

This paper investigates some common determinants of default probability changes of individual flrms using Standard & Poor's ratings database. We analyze and quantify the re- sponses of hazard rates to changes in various economic variables, namely flnancial markets, business cycle and credit indicators, and examine their persistency. First, we show that in- cluding non-flnancial information largely improves the poor explanatory

F. Couderc

325

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.

Craig Loewen

326

Judgment, probability, and Aristotle's rhetoric

Aristotle discussed various forms of rationality in the Organon and other works. Aristotle held that in making judgments, the soul used five means— intelligence, episteme (scientific knowledge), sophia (theoretical wisdom), techne (art), and phronesis (practical wisdom). The nature of rhetoric as a techne employed in persuasion and grounded in probabilities distinguishes it from discourse in natural science, metaphysics, and philosophy.

Barbara Warnick

1989-01-01

327

Intersymbol interference and error probability

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

1966-01-01

328

Arteriovenous malformation (AVM)-related aneurysms have been described in the literature. Their behavior varies based on their location in relation to and the activity of the shunting through the index AVM. The intuitive expectation supported by numerous reports is that these aneurysms should regress if the AVM is excluded from the circulation. We describe a case of 46-year-old man who presented with a posterior fossa AVM with an aneurysm on the posterior inferior cerebellar artery feeding the AVM. The nidus of the AVM was successfully excluded by glue embolization, with initial regression of the PICA aneurysm on serial imaging. Five years after the endovascular treatment, the aneurysm showed significant re-growth necessitating endovascular coiling. This case presents the re-growth of an AVM-related aneurysm and emphasizes the importance of long-term follow-up of such aneurysms even if the AVM is completely excluded. PMID:24556301

Al-Jehani, Hosam; Tampieri, Donatella; Cortes, Maria; Melançon, Denis

2014-01-01

329

Using Playing Cards to Differentiate Probability Interpretations

ERIC Educational Resources Information Center

The aprioristic (classical, naďve 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

2014-01-01

330

Remote balance weighs accurately amid high radiation

NASA Technical Reports Server (NTRS)

Commercial beam-type balance, modified and outfitted with electronic controls and digital readout, can be remotely controlled for use in high radiation environments. This allows accurate weighing of breeder-reactor fuel pieces when they are radioactively hot.

Eggenberger, D. N.; Shuck, A. B.

1969-01-01

331

Mill profiler machines soft materials accurately

NASA Technical Reports Server (NTRS)

Mill profiler machines bevels, slots, and grooves in soft materials, such as styrofoam phenolic-filled cores, to any desired thickness. A single operator can accurately control cutting depths in contour or straight line work.

Rauschl, J. A.

1966-01-01

332

Accurate capacitive metrology for atomic force microscopy

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-

2005-01-01

333

BRDF Slices: Accurate Adaptive Anisotropic Appearance Acquisition

' & $ % BRDF Slices: Accurate Adaptive Anisotropic Appearance Acquisition JirÂ´i Filip1 RadomÂ´ir VÂ´avra {filipj,vavra,haindl,zid,krupimik}@utia.cas.cz, havran@fel.cvut.cz We introduce unique publicly available

Havran, Vlastimil

334

Determination of Highly Accurate Heats of Formation

NASA Technical Reports Server (NTRS)

Two approaches for directly computing a molecular heat of formation based on sophisticated ab initio electronic structure theory axe discussed and example calculations are presented for several molecules of interest in atmospheric chemistry including HNO and CICN. The accuracy of these approaches for a small subset of the molecules is demonstrated by comparison to very accurate experimental data. A third approach for evaluating accurate heats of formation consists of combining experimental and theoretical data. The potential for this method to provide reliable thermochemical data on many molecules using accurate experimental beats of formation for only a small number of species is demonstrated by giving accurate (Delta)H(sup 0, sub f) quantities for a host of fluorine, chlorine, and bromine oxide and nitrogen oxide compounds. Potential pitfalls in all three approaches are discussed.

Lee, Timothy J.; Langhoff, Stephen R. (Technical Monitor)

1996-01-01

335

The maximum entropy method of moments and Bayesian probability theory

NASA Astrophysics Data System (ADS)

The problem of density estimation occurs in many disciplines. For example, in MRI it is often necessary to classify the types of tissues in an image. To perform this classification one must first identify the characteristics of the tissues to be classified. These characteristics might be the intensity of a T1 weighted image and in MRI many other types of characteristic weightings (classifiers) may be generated. In a given tissue type there is no single intensity that characterizes the tissue, rather there is a distribution of intensities. Often this distributions can be characterized by a Gaussian, but just as often it is much more complicated. Either way, estimating the distribution of intensities is an inference problem. In the case of a Gaussian distribution, one must estimate the mean and standard deviation. However, in the Non-Gaussian case the shape of the density function itself must be inferred. Three common techniques for estimating density functions are binned histograms [1, 2], kernel density estimation [3, 4], and the maximum entropy method of moments [5, 6]. In the introduction, the maximum entropy method of moments will be reviewed. Some of its problems and conditions under which it fails will be discussed. Then in later sections, the functional form of the maximum entropy method of moments probability distribution will be incorporated into Bayesian probability theory. It will be shown that Bayesian probability theory solves all of the problems with the maximum entropy method of moments. One gets posterior probabilities for the Lagrange multipliers, and, finally, one can put error bars on the resulting estimated density function.

Bretthorst, G. Larry

2013-08-01

336

Rota, Probability, Algebra and Logic

NASA Astrophysics Data System (ADS)

Inspired by Rota's Fubini Lectures, we present the MV-algebraic extensions of various results in probability theory, first proved for boolean algebras by De Finetti, Kolmogorov, Carathéodory, Loomis, Sikorski and others. MV-algebras stand to ?ukasiewicz infinite-valued logic as boolean algebras stand to boolean logic. Using Elliott's classification, the correspondence between countable boolean algebras and commutative AF C*-algebras extends to a correspondence between countable MV-algebras and AF C*-algebras whose Murray-von Neumann order of projections is a lattice. In this way, (faithful, invariant) MV-algebraic states are identified with (faithful, invariant) tracial states of their corresponding AF C*-algebras. Faithful invariant states exist in all finitely presented MV-algebras. At the other extreme, working in the context of ?-complete MV-algebras we present a generalization of Carathéodory boolean algebraic probability theory.

Mundici, Daniele

337

Probability densities in strong turbulence

NASA Astrophysics Data System (ADS)

In this work we, using Mellin’s transform combined with the Gaussian large-scale boundary condition, calculate probability densities (PDFs) of velocity increments P(?u,r), velocity derivatives P(u,r) and the PDF of the fluctuating dissipation scales Q(?,Re), where Re is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF P(?u,r) often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for the deviation of P(?u,r) from P(?u,r). An expression for the function D(h) of the multifractal theory, free from spurious logarithms recently discussed in [U. Frisch, M. Martins Afonso, A. Mazzino, V. Yakhot, J. Fluid Mech. 542 (2005) 97] is also obtained.

Yakhot, Victor

2006-03-01

338

Probability to Achieve TSC Goal

We propose a probabilistic measure for self-checking (SC) circuits that is analogous to reliability of fault-tolerant systems. This measure is defined as the probability to achieve totally self-checking (TSC) goal at the lth cycle: TSCG(t). TSCG provides insight to the worst case dynamic behavior of SC circuits with respect to the application environment and component failure rates. TSCG surpasses the

Jien-chung Lo; Eiji Fujiwara

1996-01-01

339

Born Rule and Noncontextual Probability

The probabilistic rule that links the formalism of Quantum Mechanics (QM) to the real world was stated by Born in 1926. Since then, there were many attempts to derive the Born postulate as a theorem, Gleason's being the most prominent. The Gleason derivation, however, is generally considered rather intricate and its physical meaning, in particular in relation with the noncontextuality of probability (NP), is not quite evident. More recently, we are witnessing a revival of interest in possible demonstrations of the Born rule, like Zurek's and Deutsch's based on the decoherence and on the theory of decisions, respectively. Despite an ongoing debate about the presence of hidden assumptions and circular reasonings, these have the merit of prompting more physically oriented approaches to the problem. Here we suggest a new proof of the Born rule based on the noncontextuality of probability. Within the theorem we also demonstrate the continuity of probability with respect to the amplitudes, which has been suggested to be a gap in Zurek's and Deutsch's approaches, and we show that NP is implicitly postulated also in their demonstrations. Finally, physical motivations of NP are given based on an invariance principle with respect to a resolution change of measurements and with respect to the principle of no-faster-than-light signalling.

Fabrizio Logiurato; Augusto Smerzi

2012-02-13

340

Probability Densities in Strong Turbulence

According to modern developments in turbulence theory, the "dissipation" scales (u.v. cut-offs) $\\eta$ form a random field related to velocity increments $\\delta_{\\eta}u$. In this work we, using Mellin's transform combined with the Gaussain large -scale boundary condition, calculate probability densities (PDFs) of velocity increments $P(\\delta_{r}u,r)$ and the PDF of the dissipation scales $Q(\\eta, Re)$, where $Re$ is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF $P_{L}(\\delta_{r}u,r)$ often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for deviation of $P(\\delta_{r}u,r)$ from $P_{L}(\\delta_{r}u,r)$. A framework for evaluation of the PDFs of various turbulence characteristics involving spatial derivatives is developed. The exact relation, free of spurious Logarithms recently discussed in Frisch et al (J. Fluid Mech. {\\bf 542}, 97 (2005)), for the multifractal probability density of velocity increments, not based on the steepest descent evaluation of the integrals is obtained and the calculated function $D(h)$ is close to experimental data. A novel derivation (Polyakov, 2005), of a well-known result of the multi-fractal theory [Frisch, "Turbulence. {\\it Legacy of A.N.Kolmogorov}", Cambridge University Press, 1995)), based on the concepts described in this paper, is also presented.

Victor Yakhot

2005-12-12

341

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

2014-07-01

342

Posterior interosseous nerve incarceration with endobutton repair of distal biceps.

Distal biceps ruptures are uncommon injuries that comprise approximately 3% of all biceps pathology. This injury is most commonly seen in 40- to 60-year-old men, and the mechanism of injury involves a forceful extension movement to a flexed elbow. Without surgical intervention, patients are left with measurable weakness in elbow flexion and supination as well as a cosmetic deformity that often leaves them dissatisfied. Consequently, early surgical repair is advocated for physically active individuals. A variety of surgical approaches and fixation devices are currently used for distal biceps repair. The single-incision cortical button repair for distal biceps avulsions has become popular since Bain introduced the technique in 2000. The advantage of the cortical button biceps repair technique is the significantly higher failure strength than either the 2-incision technique or the suture anchor repair. The initial repair strength of the cortical button technique allows immediate active elbow range of motion and accelerated rehabilitation. Additionally, the single-incision anterior approach is less invasive than the 2-incision biceps repair and results in a lower incidence of heterotopic ossification. One disadvantage of this approach, however, is the risk of injury to the posterior interosseous nerve. The authors report a case in which the posterior interosseous nerve was incarcerated between the cortical button and the radius during acute distal biceps repair, resulting in complete posterior interosseus nerve palsy. This case report details the surgery leading to the nerve palsy and the subsequent nerve exploration that identified the cause of the nerve palsy. Recommendations are made on how to avoid this complication during distal biceps tendon repairs. [Orthopedics. 2015; 38(1):e68-e71.]. PMID:25611423

Van den Bogaerde, James; Shin, Edward

2015-01-01

343

Multidimensional analysis of fetal posterior fossa in health and disease.

Fetal magnetic resonance imaging (MRI) is now routinely used to further investigate cerebellar malformations detected with ultrasound. However, the lack of 2D and 3D biometrics in the current literature hinders the detailed characterisation and classification of cerebellar anomalies. The main objectives of this fetal neuroimaging study were to provide normal posterior fossa growth trajectories during the second and third trimesters of pregnancy via semi-automatic segmentation of reconstructed fetal brain MR images and to assess common cerebellar malformations in comparison with the reference data. Using a 1.5-T MRI scanner, 143 MR images were obtained from 79 normal control and 53 fetuses with posterior fossa abnormalities that were grouped according to the severity of diagnosis on visual MRI inspections. All quantifications were performed on volumetric datasets, and supplemental outcome information was collected from the surviving infants. Normal growth trajectories of total brain, cerebellar, vermis, pons and fourth ventricle volumes showed significant correlations with 2D measurements and increased in second-order polynomial trends across gestation (Pearson r, p?posterior fossa biometrics enhance the delineation of normal and abnormal cerebellar phenotypes on fetal MRI and confirm the advantages of utilizing advanced neuroimaging tools in clinical fetal research. PMID:23553467

Vatansever, Deniz; Kyriakopoulou, Vanessa; Allsop, Joanna M; Fox, Matthew; Chew, Andrew; Hajnal, Joseph V; Rutherford, Mary A

2013-10-01

344

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

1995-01-01

345

Bilaterally absent posterior inferior cerebellar artery: case report.

Posterior inferior cerebellar artery (PICA) is one of the cerebellar arteries which originates from the vertebral artery and has the most complex and variable course. The PICA usually originates from the vertebral artery intracranially as a single trunk, however, absent, double trunk, extracranial, and extradural PICA may also exist. In a collection of 50 cerebellar specimens (100 hemispheres) injected with colored gelatin, one case of bilaterally absent PICA was encountered, male aged 59 (causes of the death was not taken into consideration). PMID:23337996

Sharifi, Mansoor; Ciszek, Bogdan

2013-09-01

346

Thoracoscopic resection of functional posterior mediastinal paraganglioma: a case report

A 48-year-old man with posterior mediastinal mass was diagnosed as functional mediastinal paraganglioma during surgical exploration via open thoracotomy in another hospital. The operation was terminated because of severe hypertension when touching the tumor. He was transferred to our center later. After systemic evaluation, the patient was medicated with oral alpha- and beta-blockades, as well as intravenous fluid resuscitation for two weeks. His blood pressure became stable and a second operation was planned. The tumor was removed completely via the thoracoscopic approach, and was finally confirmed as functional paraganglioma by immunohistochemistry. The patient recovered uneventfully after surgery, with no recurrence during one year follow-up visit.

Ma, Lin; Mei, Jianong

2014-01-01

347

The posterior approach for low retrorectal tumors in adults

Background and aims Retrorectal tumors are uncommon in adults and arise in different tissues in the presacral space. The aim of this study is\\u000a to evaluate early complete surgical resection by a perineal approach as the therapy-of-choice for tumors under the sacral\\u000a promontory.\\u000a \\u000a \\u000a \\u000a Patients and methods We evaluated the posterior approach, especially intersphincteric and parasacrococcygeal excisions, in terms of resectability,\\u000a morbidity, risk

Nicolas Buchs; Sophia Taylor; Bruno Roche

2007-01-01

348

Calcified angioleiomyoma of foot arising from the posterior tibial artery

Case A 77-year-old woman was presented with a mass in the plantar side of left foot. Physical examinations revealed 30?×?20-mm-sized\\u000a hard mass with tenderness. Plane X-ray and computed tomography showed heterogenously calcified tumor that contacted with posterior\\u000a tibial artery. Magnetic resonance imaging indicated spindle-shaped tumor in subcutis. That was isointense and hypointense\\u000a on the T1-weighted image and hyperintense on the T2-weighted

Masaru Kadowaki; Soichiro Yamamoto; Yuji Uchio

2010-01-01

349

Visual impairment and posterior cortical atrophy preceding rapid progressive dementia

Posterior cortical atrophy (PCA), also known as Benson's disease, has been previously reported as a variant of Alzheimer's disease (AD). We present a clinical picture and MRI findings of a patient with PCA who developed early right-sided homonymous haemianopia and marked atrophy of parieto-occipital regions of the brain before a cognitive decline appeared. This case demonstrates that PCA may appear with advanced brain atrophy at the onset of focal visual deficits before the development of progressive dementia, and adds to the knowledge of dementias with rapid progression. PMID:23283613

Müller, Kai Ivar; Bekkelund, Svein Ivar

2013-01-01

350

Aneurysmal subarachnoid hemorrhage with concomitant posterior communicating artery fenestration.

Fenestrations of the posterior communicating artery (PCoA) are extremely rare. Associated aneurysms have only been documented three times in the literature, and none associated with a subarachnoid hemorrhage. We describe a 52-year-old female who presented with a subarachnoid hemorrhage secondary to a ruptured saccular aneurysm at the proximal limb of a fenestrated right PCoA. The patient was also found to have bilateral middle cerebral artery (MCA) aneurysms. Surgical management included surmising the etiology of the subarachnoid hemorrhage with subsequent clipping of both the right PCoA and MCA aneurysm. The potential embryological mechanisms leading to a PCoA fenestration are discussed. PMID:24761761

Weiner, Gregory M; Grandhi, Ramesh; Zwagerman, Nathan T; Agarwal, Nitin; Friedlander, Robert M

2015-02-01

351

Endoscopic options in management of posterior third ventricular tumors

Objective A spectrum of both radiosensitive and radio-resistant lesions occurs in the region of the posterior third ventricle (PTV).\\u000a Most of these are associated with hydrocephalus requiring a cerebrospinal fluid diversion procedure. The present study aims\\u000a to assess the effectiveness of endoscopic biopsy and third ventriculostomy (ETV) in these patients.\\u000a \\u000a \\u000a \\u000a Materials and methods Twenty-four patients with PTV lesions with moderate to severe

S. V. Roopesh Kumar; Aaron Mohanty; Vani Santosh; Satyanarayana Satish; B. Indira Devi; Shanti Shankar Praharaj; Sastry V. R. Kolluri

2007-01-01

352

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 five 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.

2015-01-01

353

Considerations for ceramic inlays in posterior teeth: a review

This review of ceramic inlays in posterior teeth includes a review of the history of ceramic restorations, followed by common indications and contraindications for their use. A discussion on the potential for tooth wear is followed by a review of recommended preparation design considerations, fabrication methods, and material choices. Despite the improved materials available for fabrication of porcelain inlays, fracture remains a primary mode of inlay failure. Therefore, a brief discussion on strengthening methods for ceramics is included. The review concludes with a section on luting considerations, and offers the clinician specific recommendations for luting procedures. In conclusion, inlay success rates and longevity, as reported in the literature, are summarized. PMID:23750101

Hopp, Christa D; Land, Martin F

2013-01-01

354

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

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

2013-09-02

355

COMPUTATIONAL HARDNESS OF VALIDITY IN PROBABILITY LOGIC

COMPUTATIONAL HARDNESS OF VALIDITY IN PROBABILITY LOGIC RUTGER KUYPER Abstract. We consider the complexity of validity in -logic, a probability logic introduced by Terwijn. We prove that the set of valid, there have been many attempts at combining logic and probability through so-called probability logics. We

Bosma, Wieb

356

Probability for Weather and Climate

NASA Astrophysics Data System (ADS)

Over the last 60 years, the availability of large-scale electronic computers has stimulated rapid and significant advances both in meteorology and in our understanding of the Earth System as a whole. The speed of these advances was due, in large part, to the sudden ability to explore nonlinear systems of equations. The computer allows the meteorologist to carry a physical argument to its conclusion; the time scales of weather phenomena then allow the refinement of physical theory, numerical approximation or both in light of new observations. Prior to this extension, as Charney noted, the practicing meteorologist could ignore the results of theory with good conscience. Today, neither the practicing meteorologist nor the practicing climatologist can do so, but to what extent, and in what contexts, should they place the insights of theory above quantitative simulation? And in what circumstances can one confidently estimate the probability of events in the world from model-based simulations? Despite solid advances of theory and insight made possible by the computer, the fidelity of our models of climate differs in kind from the fidelity of models of weather. While all prediction is extrapolation in time, weather resembles interpolation in state space, while climate change is fundamentally an extrapolation. The trichotomy of simulation, observation and theory which has proven essential in meteorology will remain incomplete in climate science. Operationally, the roles of probability, indeed the kinds of probability one has access too, are different in operational weather forecasting and climate services. Significant barriers to forming probability forecasts (which can be used rationally as probabilities) are identified. Monte Carlo ensembles can explore sensitivity, diversity, and (sometimes) the likely impact of measurement uncertainty and structural model error. The aims of different ensemble strategies, and fundamental differences in ensemble design to support of decision making versus advance science, are noted. It is argued that, just as no point forecast is complete without an estimate of its accuracy, no model-based probability forecast is complete without an estimate of its own irrelevance. The same nonlinearities that made the electronic computer so valuable links the selection and assimilation of observations, the formation of ensembles, the evolution of models, the casting of model simulations back into observables, and the presentation of this information to those who use it to take action or to advance science. Timescales of interest exceed the lifetime of a climate model and the career of a climate scientist, disarming the trichotomy that lead to swift advances in weather forecasting. Providing credible, informative climate services is a more difficult task. In this context, the value of comparing the forecasts of simulation models not only with each other but also with the performance of simple empirical models, whenever possible, is stressed. The credibility of meteorology is based on its ability to forecast and explain the weather. The credibility of climatology will always be based on flimsier stuff. Solid insights of climate science may be obscured if the severe limits on our ability to see the details of the future even probabilistically are not communicated clearly.

Smith, L. A.

2013-12-01

357

Arthroscopic ulnar nerve identification during posterior elbow arthroscopy.

Elbow arthroscopy has increased in popularity in the past 10 years for both diagnostic and therapeutic purposes. A major limiting factor faced by the elbow arthroscopist is the close proximity of the neurovasculature to the working field, with the risk of iatrogenic injury. Many arthroscopic procedures are less extensive than their open equivalents because of an inability to consistently and safely eliminate the risk of neural and vascular injury. Many open procedures in the posterior compartment of the elbow joint are not routinely performed arthroscopically. The primary reason for this restriction in arthroscopic practice is the locality of the posteromedially positioned ulnar nerve in the posterior compartment. Experience and practice with elbow arthroscopic techniques allows surgeons to expand the indications for arthroscopic treatment of an increasing number of elbow pathologies. A philosophy that is routine in open surgery when dealing with pathology that is adjacent to neurovasculature is to identify the neurovasculature and hence reduce the risk of injury. Our aim is to translate this philosophy to arthroscopy by helping define a safe technique for identifying the ulnar nerve in the posteromedial elbow gutter and allowing for a safer performance of procedures in the posteromedial region of the elbow. PMID:23766965

Kamineni, Srinath; Hamilton, David Anthony

2012-09-01

358

Posterior Urethral Valves: Renal Failure and Prenatal Treatment

Posterior urethral valves occur in 1?:?5000 live births. Despite the high prevalence, the few children that survive do poorly, with over 50% progressing to ESRD in 10 years. The gold standard for post-natal diagnosis is voiding cystourethrography, while pre-natal diagnosis is dependent on routine screening ultrasonography. Despite the ability to identify features of bladder outlet obstruction early in fetal development, there is no consensus on how to incorporate early detection into current screening protocols. There has yet to be a marker that allows prediction of obstruction in the absence of or prior to radiographic evidence of obstruction. With our current screening strategy, the majority of interventions are performed well after irreversible damage has occurred. Improved mortality and long term morbidity from posterior urethral valves and congenital bladder outlet obstruction will likely remain unchanged until it is possible to intervene prior to the onset of irreversible renal damage. New biologic markers and improved instrumentation will allow for more effective diagnosis and intervention at earlier stages of fetal development. PMID:21860792

Casella, Daniel P.; Tomaszewski, Jeffrey J.; Ost, Michael C.

2012-01-01

359

Patient risk factors' influence on survival of posterior composites.

This practice-based retrospective study evaluated the survival of resin composite restorations in posterior teeth, focusing on the influence of potential patient risk factors. In total, 306 posterior composite restorations placed in 44 adult patients were investigated after 10 to 18 yrs. The history of each restoration was extracted from the dental records, and a clinical evaluation was performed with those still in situ. The patient risk status was assessed for caries and "occlusal-stress" (bruxism-related). Statistical analysis was performed by the Kaplan-Meier method and Cox-regression multivariate analysis. In total, 30% of the restorations failed, of which 82% were found in patients with 1 or 2 risk factors. Secondary caries was the main reason of failure within caries-risk patients, whereas fracture was the main reason in "occlusal-stress-risk" patients. The patient variables gender and age did not significantly affect survival, but risk did (p < .001). Tooth type (p < .001), arch (p = .013), and pulpal vitality (p = .003) significantly affected restoration survival. Within the limits of this retrospective evaluation, the survival of restorations is affected by patient risk factors, which should be included in survival analyses of restorations. PMID:23690354

van de Sande, F H; Opdam, N J; Rodolpho, P A Da Rosa; Correa, M B; Demarco, F F; Cenci, M S

2013-07-01

360

Posterior parietal cortex dynamically ranks topographic signals via cholinergic influence

The hypothesis to be discussed in this review is that posterior parietal cortex (PPC) is directly involved in selecting relevant stimuli and filtering irrelevant distractors. The PPC receives input from several sensory modalities and integrates them in part to direct the allocation of resources to optimize gains. In conjunction with prefrontal cortex, nucleus accumbens, and basal forebrain cholinergic nuclei, it comprises a network mediating sustained attentional performance. Numerous anatomical, neurophysiological, and lesion studies have substantiated the notion that the basic functions of the PPC are conserved from rodents to humans. One such function is the detection and selection of relevant stimuli necessary for making optimal choices or responses. The issues to be addressed here are how behaviorally relevant targets recruit oscillatory potentials and spiking activity of posterior parietal neurons compared to similar yet irrelevant stimuli. Further, the influence of cortical cholinergic input to PPC in learning and decision-making is also discussed. I propose that these neurophysiological correlates of attention are transmitted to frontal cortical areas contributing to the top-down selection of stimuli in a timely manner. PMID:22712008

Broussard, John I.

2012-01-01

361

A mass in the posterior mediastinum; extramedullary haemopoietic tissue.

Extramedullary haematopoiesis is a very rare cause of a posterior mediastinal tumour and may be clinically confused with many other mediastinal tumours; benign or malignant. Extramedullary haematopoiesis is a really rare cause of haemothorax and usually it is diagnosed incidentally. Extramedullary masses complicating thalassemias, apart from the known complications, may also bleed and produce acute manifestations like dyspnoea and fatigue. Pathologically, the masses are soft, deep red, and resemble spleen tissue on the cut surface. Histologically, they are formed of hematopoietic tissue mixed with adipose elements. The mass is extremely vascular and contains some fibrous tissue. This particular structure renders the mass prone to haemorrhage. We report a case of posterior mediastinal extramedullary haematopoietic mass in a 56-year-old man who presented with non-specific symptomatology and a paravertebral mass on chest X-ray and in the chest computed tomography. A percutaneous biopsy approach could be technically difficult due to the special location of the mass. Video assisted thoracic surgery (VATS), is a minimal invasive and alternative way of diagnosis, biopsy and treatment of these cases. Diagnosis was achieved in our patient by mini thoracotomy and open biopsy in order to prevent bleeding or neurological damage. PMID:22774413

Baikoussis, N G; Beis, J P; Verra, C; Siminelakis, S N

2012-05-01

362

Spatio-Temporal Updating in the Left Posterior Parietal Cortex

Adopting an unusual posture can sometimes give rise to paradoxical experiences. For example, the subjective ordering of successive unseen tactile stimuli delivered to the two arms can be affected when people cross them. A growing body of evidence now highlights the role played by the parietal cortex in spatio-temporal information processing when sensory stimuli are delivered to the body or when actions are executed; however, little is known about the neural basis of such paradoxical feelings resulting from such unusual limb positions. Here, we demonstrate increased fMRI activation in the left posterior parietal cortex when human participants adopted a crossed hands posture with their eyes closed. Furthermore, by assessing tactile temporal order judgments (TOJs) in the same individuals, we observed a positive association between activity in this area and the degree of reversal in TOJs resulting from crossing arms. The strongest positive association was observed in the left intraparietal sulcus. This result implies that the left posterior parietal cortex may be critically involved in monitoring limb position and in spatio-temporal binding when serial events are delivered to the limbs. PMID:22768126

Wada, Makoto; Takano, Kouji; Ikegami, Shiro; Ora, Hiroki; Spence, Charles; Kansaku, Kenji

2012-01-01

363

Posterior Cricoarytenoid Muscle Dynamics in Canines and Humans

Objective The posterior cricoarytenoid (PCA) muscle is the sole abductor of the glottis and serves important functions during respiration, phonation, cough, and sniff. The present study examines vocal fold abduction dynamics during PCA muscle activation. Study Design Basic science study using an in vivo canine model and human subjects. Methods In four canines and five healthy humans vocal fold abduction time was measured using high speed video recording. In the canines, PCA muscle activation was achieved using graded stimulation of the PCA nerve branch. The human subjects performed coughing and sniffing tasks. High speed video and audio signals were concurrently recorded. Results In the canines the vocal fold moved posteriorly, laterally, and superiorly during abduction. Average time to reach 10%, 50% and 90% abduction was 23, 50, and 100 ms with low stimulation, 24, 58, and 129 ms with medium stimulation, and 21, 49, and 117 ms with high level stimulation. In the humans, 100% abduction times for coughing and sniffing tasks were 79 and 193 ms, respectively. Conclusion The PCA abduction times in canines are within the range in humans. The results also further support the notion that PCA muscles are fully active during cough. Level of Evidence N/A (Animal studies and basic research) PMID:24781959

Chhetri, Dinesh K.; Neubauer, Juergen; Sofer, Elazar

2015-01-01

364

Management of disorders of the posterior pelvic floor.

INTRODUCTION: Constipation is a relatively common problem affecting 15 percent of adults in the Western world, and over half of these cases are related to pelvic floor disorders. This article reviews the clinical presentation and diagnostic approach to posterior pelvic floor disorders, including how to image and treat them. METHODS: A Pubmed search using keywords "rectal prolapse," "rectocele," "perineal hernia," and "anismus" was performed, and bibliographies of the revealed articles were cross-referenced to obtain a representative cross-section of the literature, both investigational studies and reviews, that are currently available on posterior pelvic floor disorders. DISCUSSION: Pelvic floor disorders can occur with or without concomitant physical anatomical defects, and there are a number of imaging modalities available to detect such abnormalities in order to decide on the appropriate course of treatment. Depending on the nature of the disorder, operative or non-operative therapy may be indicated. CONCLUSION: Correctly diagnosing pelvic floor disorders can be complex and challenging, and the various imaging modalities as well as clinical history and exam must be considered together in order to arrive at a diagnosis. PMID:16720016

Berman, Loren; Aversa, John; Abir, Farshad; Longo, Walter E.

2005-01-01

365

The Black Hole Formation Probability

NASA Astrophysics Data System (ADS)

A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we investigate the probability that a star will make a BH as a function of its ZAMS mass. Although the shape of the black hole formation probability function is poorly constrained by current measurements, we believe that this framework is an important new step toward better understanding BH formation. We also consider some of the implications of this probability distribution, from its impact on the chemical enrichment from massive stars, to its connection with the structure of the core at the time of collapse, to the birth kicks that black holes receive. A probabilistic description of BH formation will be a useful input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

Clausen, Drew R.; Piro, Anthony; Ott, Christian D.

2015-01-01

366

(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

2014-08-01

367

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

2014-09-01

368

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

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

2014-01-01

369

While a wealth of evidence suggests that humans tend to rely on additive cue combination to make controlled judgments, many of the normative rules for probability combination require multiplicative combination. In this article, the authors combine the experimental paradigms on probability reasoning and multiple-cue judgment to allow a comparison between formally identical tasks that involve probability vs. other task contents. The purpose was to investigate if people have cognitive algorithms for the combination, specifically, of probability, affording multiplicative combination in the context of probability. Three experiments suggest that, although people show some signs of a qualitative understanding of the combination rules that are specific to probability, in all but the simplest cases they lack the cognitive algorithms needed for multiplication, but instead use a variety of additive heuristics to approximate the normative combination. Although these heuristics are surprisingly accurate, normative combination is not consistently achieved until the problems are framed in an additive way. PMID:25514208

Juslin, Peter; Lindskog, Marcus; Mayerhofer, Bastian

2015-03-01

370

Lectures on probability and statistics

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.

1984-09-01

371

Target intersection probabilities for parallel-line and continuous-grid types of search

The expressions for calculating the probability of intersection of hidden targets of different sizes and shapes for parallel-line and continuous-grid types of search can be formulated by vsing the concept of conditional probability. When the prior probability of the orientation of a widden target is represented by a uniform distribution, the calculated posterior probabilities are identical with the results obtained by the classic methods of probability. For hidden targets of different sizes and shapes, the following generalizations about the probability of intersection can be made: (1) to a first approximation, the probability of intersection of a hidden target is proportional to the ratio of the greatest dimension of the target (viewed in plane projection) to the minimum line spacing of the search pattern; (2) the shape of the hidden target does not greatly affect the probability of the intersection when the largest dimension of the target is small relative to the minimum spacing of the search pattern, (3) the probability of intersecting a target twice for a particular type of search can be used as a lower bound if there is an element of uncertainty of detection for a particular type of tool; (4) the geometry of the search pattern becomes more critical when the largest dimension of the target equals or exceeds the minimum spacing of the search pattern; (5) for elongate targets, the probability of intersection is greater for parallel-line search than for an equivalent continuous square-grid search when the largest dimension of the target is less than the minimum spacing of the search pattern, whereas the opposite is true when the largest dimension exceeds the minimum spacing; (6) the probability of intersection for nonorthogonal continuous-grid search patterns is not greatly different from the probability of intersection for the equivalent orthogonal continuous-grid pattern when the orientation of the target is unknown. The probability of intersection for an elliptically shaped target can be approximated by treating the ellipse as intermediate between a circle and a line. A search conducted along a continuous rectangular grid can be represented as intermediate between a search along parallel lines and along a continuous square grid. On this basis, an upper and lower bound for the probability of intersection of an elliptically shaped target for a continuous rectangular grid can be calculated. Charts have been constructed that permit the values for these probabilities to be obtained graphically. The use of conditional probability allows the explorationist greater flexibility in considering alternate search strategies for locating hidden targets. ?? 1977 Plenum Publishing Corp.

McCammon, R.B.

1977-01-01

372

Influence of Connector Width on the Stress Distribution of Posterior Bridges under Loading

Objective: In all ceramic fixed partial dentures the connector area is a common fracture location. The survival time of three-unit fixed partial dentures may be improved by altering the connector design in regions of maximum tension. The purpose of this study was to determine the effect of buccolingual increase of the connector width on the stress distribution in posterior fixed partial dentures made of IPS Empress 2. To simulate the anatomical condition, we used three-dimensional finite element analysis to generate. Materials and Methods: Three models of three-unit bridges replacing the first molar were prepared. The buccolingual connector width varied from 3.0 to 5.0 mm. Bridges were vertically loaded with 600 N at one point on the central fossa of the pontic, at 12 points along the cusp-fossa contact (50 N each), or at eight points along the cusp-marginal ridge contact (75 N each). Alternatively, a load of 225 N was applied at a 45ş angle from the lingual side. Results: Stress concentrations were observed within or near the connectors. The von Mises stress decreased by increasing connector width, regardless of whether the loading was applied vertically or at an angle. Conclusion: Within the limitations of this study, we conclude that increasing the connector width decreases the failure probability when a vertical or angled load is applied. PMID:21998811

Rezaei, S. Mir Mohammad; Heidarifar, H.; Arezodar, F. Fallahi; Azary, A.; Mokhtarykhoee, S.

2011-01-01

373

Accurate radio positions with the Tidbinbilla interferometer

NASA Technical Reports Server (NTRS)

The Tidbinbilla interferometer, designed specifically to provide accurate radio position measurements of compact radio sources in the Southern Hemisphere with high sensitivity using the 26 m and 64 m antennas of the Deep Space Network at Tidbinbilla, near Canberra, is discussed. The instrument also provides high accuracy flux density measurements for compact radio sources.

Batty, M. J.; Jauncey, D. J.; Rayner, P. T.; Gulkis, S.

1980-01-01

374

ACCURATE SPECTRAL ENVELOPE ESTIMATION FOR ARTICULATIONTOSPEECH SYNTHESIS

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

Edinburgh, University of

375

Accurate Assessment--Compelling Evidence for Practice

ERIC Educational Resources Information Center

Childhood overweight and obesity is a public health concern not just because of its growing prevalence but also for its serious and lasting health consequences. Though height and weight measures are easy to obtain and New Hampshire Head Start sites measure height and weight of their enrollees, there are numerous challenges related to accurate…

Flynn, Regina T.; Anderson, Ludmila; Martin, Nancy R.

2010-01-01

376

Steps toward accurate math word problem translation

In this paper, a novel multi-phase architecture for an accurate math word translation system is proposed. This system, żMathMasterż, was designed to help students to gradually develop skills required to solve math word problems. Math word problems are difficult for students because they require the student to comprehend the verbal problem, to identify relevant information in a word problem and

Wanintorn Supap; Kanlaya Naruedomkul; Nick Cercone

2009-01-01

377

Accurate On-line Support Vector Regression

Batch implementations of support vector regression (SVR) are inefé cient when used in an on-line setting because they must be retrained from scratch every time the training set is modié ed. Following an incremen- tal support vector classié cation algorithm introduced by Cauwenberghs and Poggio (2001), we have developed an accurate on-line support vec- tor regression (AOSVR) that efé ciently

Junshui Ma; James Theiler; Simon Perkins

2003-01-01

378

Prior anterograde tracing work identified somatotopically organized lamina I trigemino- and spino-thalamic terminations in a cytoarchitectonically distinct portion of posterolateral thalamus of the macaque monkey, named the posterior part of the ventral medial nucleus (VMpo; Craig, 2004b). Microelectrode recordings from clusters of selectively thermoreceptive or nociceptive neurons were used to guide precise micro-injections of various tracers in VMpo. A prior report (Craig and Zhang, 2006) described retrograde tracing results, which confirmed the selective lamina I input to VMpo and the antero-posterior (head to foot) topography. The present report describes the results of micro-injections of anterograde tracers placed at different levels in VMpo, based on the antero-posterior topographic organization of selectively nociceptive units and clusters over nearly the entire extent of VMpo. Each injection produced dense, patchy terminal labeling in a single coherent field within a distinct granular cortical area centered in the fundus of the superior limiting sulcus. The terminations were distributed with a consistent antero-posterior topography over the posterior half of the superior limiting sulcus. These observations demonstrate a specific VMpo projection area in dorsal posterior insular cortex that provides the basis for a somatotopic representation of selectively nociceptive lamina I spinothalamic activity. These results also identify the VMpo terminal area as the posterior half of interoceptive cortex; the anterior half receives input from the vagal-responsive and gustatory neurons in the basal part of the ventral medial nucleus (VMb). PMID:23853108

Craig, A.D. (Bud)

2014-01-01

379

Exploring the Overestimation of Conjunctive Probabilities

People often overestimate probabilities of conjunctive events. The authors explored whether the accuracy of conjunctive probability estimates can be improved by increased experience with relevant constituent events and by using memory aids. The first experiment showed that increased experience with constituent events increased the correlation between the estimated and the objective conjunctive probabilities, but that it did not reduce overestimation of conjunctive probabilities. The second experiment showed that reducing cognitive load with memory aids for the constituent probabilities led to improved estimates of the conjunctive probabilities and to decreased overestimation of conjunctive probabilities. To explain the cognitive process underlying people’s probability estimates, the configural weighted average model was tested against the normative multiplicative model. The configural weighted average model generates conjunctive probabilities that systematically overestimate objective probabilities although the generated probabilities still correlate strongly with the objective probabilities. For the majority of participants this model was better than the multiplicative model in predicting the probability estimates. However, when memory aids were provided, the predictive accuracy of the multiplicative model increased. In sum, memory tools can improve people’s conjunctive probability estimates. PMID:23460026

Nilsson, Hĺkan; Rieskamp, Jörg; Jenny, Mirjam A.

2013-01-01

380

Aim To evaluate retention of complete denture base with different types of posterior palatal seals. Material and methods Ten male patients between the age group of 50 years to 60 years were selected for the study. After the primary and secondary impressions were taken, five casts were made including a cast without posterior palatal seal, a cast with single bead posterior palatal seal, a cast with double bead posterior palatal seal, a cast with butterfly shaped posterior palatal seal, and a cast with posterior palatal seal with low fusing compound by functional method. Results It was observed that retention increased up to 108% in the posterior palatal seal with low fusing compound with functional method and the posterior palatal seal that was obtained by using functional method provided greater retention than a denture base without posterior palatal seal. Conclusion It was concluded that the incorporation of a posterior palatal seal is important for obtaining optimum retention of the maxillary complete denture. PMID:25473314

Chandu, GS; Hema, BS; Mahajan, Harsh; Azad, Antriksh; Sharma, Ipsita; Azad, Anurag

2014-01-01

381

MSPI False Indication Probability Simulations

This paper examines false indication probabilities in the context of the Mitigating System Performance Index (MSPI), in order to investigate the pros and cons of different approaches to resolving two coupled issues: (1) sensitivity to the prior distribution used in calculating the Bayesian-corrected unreliability contribution to the MSPI, and (2) whether (in a particular plant configuration) to model the fuel oil transfer pump (FOTP) as a separate component, or integrally to its emergency diesel generator (EDG). False indication probabilities were calculated for the following situations: (1) all component reliability parameters at their baseline values, so that the true indication is green, meaning that an indication of white or above would be false positive; (2) one or more components degraded to the extent that the true indication would be (mid) white, and “false” would be green (negative) or yellow (negative) or red (negative). In key respects, this was the approach taken in NUREG-1753. The prior distributions examined were the constrained noninformative (CNI) prior used currently by the MSPI, a mixture of conjugate priors, the Jeffreys noninformative prior, a nonconjugate log(istic)-normal prior, and the minimally informative prior investigated in (Kelly et al., 2010). The mid-white performance state was set at ?CDF = ?10 ? 10-6/yr. For each simulated time history, a check is made of whether the calculated ?CDF is above or below 10-6/yr. If the parameters were at their baseline values, and ?CDF > 10-6/yr, this is counted as a false positive. Conversely, if one or all of the parameters are set to values corresponding to ?CDF > 10-6/yr but that time history’s ?CDF < 10-6/yr, this is counted as a false negative indication. The false indication (positive or negative) probability is then estimated as the number of false positive or negative counts divided by the number of time histories (100,000). Results are presented for a set of base case parameter values, and three sensitivity cases in which the number of FOTP demands was reduced, along with the Birnbaum importance of the FOTP.

Dana Kelly; Kurt Vedros; Robert Youngblood

2011-03-01

382

ERIC Educational Resources Information Center

Research has shown that children repeat high-probability phoneme sequences more accurately than low-probability ones. This effect attenuates with age, and its decrease is predicted by developmental changes in the size of the lexicon (J. Edwards, M. E. Beckman, & B. Munson, 2004; B. Munson, 2001; B. Munson, J. Edwards, & M. Beckman, 2005). This…

Munson, Benjamin; Kurtz, Beth A.; Windsor, Jennifer

2005-01-01

383

Assigning probabilities to Mascot peptide identification using logistic regression.

We propose a method to assign probabilities to Mascot peptide identification by using logistic regression. Three key scores, Mascot ions score (MIS), identity threshold, and homology threshold, are integrated into the logistic regression model. Two features in the model are constructed as the differences between MIS and the two thresholds, respectively. Newton-Raphson method is then adopted to solve the model and the weight vector is estimated by maximizing the likelihood of training data. By applying the method to two datasets with known validity, the results demonstrate that the proposed method can assign accurate probabilities to Mascot peptide identifications and have a high discrimination power to separate correct and incorrect peptide identifications. PMID:20865505

Shi, Jinhong; Wu, Fang-Xiang

2010-01-01

384

Information Invariance and Quantum Probabilities

We consider probabilistic theories in which the most elementary system, a two-dimensional system, contains one bit of information. The bit is assumed to be contained in any complete set of mutually complementary measurements. The requirement of invariance of the information under a continuous change of the set of mutually complementary measurements uniquely singles out a measure of information, which is quadratic in probabilities. The assumption which gives the same scaling of the number of degrees of freedom with the dimension as in quantum theory follows essentially from the assumption that all physical states of a higher dimensional system are those and only those from which one can post-select physical states of two-dimensional systems. The requirement that no more than one bit of information (as quantified by the quadratic measure) is contained in all possible post-selected two-dimensional systems is equivalent to the positivity of density operator in quantum theory.

Caslav Brukner; Anton Zeilinger

2009-05-05

385

Supervised learning of probability distributions by neural networks

NASA Technical Reports Server (NTRS)

Supervised learning algorithms for feedforward neural networks are investigated analytically. The back-propagation algorithm described by Werbos (1974), Parker (1985), and Rumelhart et al. (1986) is generalized by redefining the values of the input and output neurons as probabilities. The synaptic weights are then varied to follow gradients in the logarithm of likelihood rather than in the error. This modification is shown to provide a more rigorous theoretical basis for the algorithm and to permit more accurate predictions. A typical application involving a medical-diagnosis expert system is discussed.

Baum, Eric B.; Wilczek, Frank

1988-01-01

386

Partial or complete absence of the posterior arch of the atlas is a well-documented anomaly but a relatively rare condition. This condition is usually asymptomatic so most are diagnosed incidentally. There have been a few documented cases of congenital defects of the posterior arch of the atlas combined with atlantoaxial subluxation. We report a very rare case of congenital anomaly of the atlas combined with atlantoaxial subluxation, that can be misdiagnosed as posterior arch fracture. PMID:24605195

Park, Yung; Kim, Seong Min; Lee, Yun Tae; Yoo, Ju Hyung; Oh, Hyun Chul; Ha, Joong-Won; Sung, Seung Yong; Yoon, Han Kook; Chang, Jee-Hoon; Jung, Jeung-Yeul

2014-03-01

387

Giant posterior inferior cerebellar artery aneurysm associated with foramen magnum syndrome.

The case of a giant distal posterior inferior cerebellar artery (PICA) aneurysm which caused foramen magnum syndrome is presented. A 67-year-old male was referred for evaluation of a posterior fossa mass lesion on MRI scan. Craniotomy was performed which revealed a giant and completely thrombosed aneurysm of the distal PICA, which was subsequently excised intact. This report adds giant aneurysm of the PICA to the list of posterior fossa lesions reported which cause foramen magnum syndrome. PMID:8296475

Richmond, B K; Schmidt, J H

1993-11-01

388

Posterior Vertebral Column Resection for VATER/VACTERL Associated Spinal Deformity: A Case Report

The VATER/VACTERL association is a syndrome notable for congenital vertebral malformations, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, and renal or limb malformations. Vertebral malformations may include the entire spectrum of congenital spinal deformities, including kyphosis, as was seen in this case. A 14-year-old girl presented to our institution with severe rigid sagittal deformity in the thoracolumbar spine that had recurred following three prior spinal fusion surgeries: the first posterior only, the second anterior and posterior, and the third a posterior only proximal extension. These surgeries were performed to control progressive kyphosis from a complex failure of segmentation that resulted in a 66° kyphosis from T11 to L3 by the time she was 9 years old. Our evaluation revealed solid arthrodesis from the most recent procedures with resultant sagittal imbalance, and surgical options to restore balance included anterior and posterior revision spinal fusion with osteotomies, multiple posterior extension osteotomies with circumferential spine fusion, and posterior vertebral column resection with circumferential spine fusion. She was advised that multiple posterior extension osteotomies would likely be insufficient to restore sagittal balance in the setting of solid arthrodesis from anterior and posterior surgery, and that the posterior-only vertebral column resection would provide results equivalent to revision anterior and posterior surgery, without the morbidity of the anterior approach. She successfully underwent posterior vertebrectomy and circumferential spinal fusion with instrumentation and is doing well 2 years postoperatively. Severe rigid sagittal deformity can be effectively managed with a posterior-only surgical approach, vertebrectomy, and circumferential spinal fusion with instrumentation. PMID:18751773

Cunningham, Matthew E.; Charles, Gina

2006-01-01

389

Postoperative swallowing function after posterior fossa tumor resection in pediatric patients

Objective After tumor resection involving the posterior fossa, postoperative swallowing dysfunction may be anticipated. This retrospective study was designed to document swallowing abnormalities in children after posterior fossa brain tumor surgery and to recommend management approaches for children at risk for aspiration.Methods Twenty-four children referred postoperatively for a video fluoroscopic swallow study (VFSS) out of 127 children undergoing posterior fossa surgery for

Lisa A. Newman; Frederick A. Boop; Robert A. Sanford; Jerome W. Thompson; Carrie K. Temple; Christopher D. Duntsch

2006-01-01

390

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

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

2012-01-01

391

Asymptotic approximations to posterior distributions via conditional moment equations

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.

2002-01-01

392

Posterior mediastinal venous masses in patients with portal hypertension.

Of 304 consecutive splenic venograms performed for suspected portal hypertension, oesophageal collateral veins were filled in 145. In seven patients massively dilated paraoesophageal collaterals were visible on the plain chest radiograph as a retrocardiac posterior mediastinal mass. Erect and supine radiographs have been compared in four patients, and the Valsalva and Mueller manoeuvres performed in one patient. The size of the masses was unchanged by these procedures, which were therefore of no value in differential diagnosis. The mass was still present immediately after portocaval anastomosis in one patient, but in another is no longer seen on radiographs taken seven years postoperatively. All seven patients also had submucosal oesophageal varices and therefore the barium swallow remains the most useful study to clarify the nature of a retrocardiac mass. Correct identification of pseudotumoural venous collaterals may avoid unnecessary further investigation. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 PMID:1140628

Moult, P J; Waite, D W; Dick, R

1975-01-01

393

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

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

2012-05-27

394

Posterior reversible encephalopathy syndrome (PRES) and CT perfusion changes

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

2012-01-01

395

The subcommissural organ and the development of the posterior commissure.

Growing axons navigate through the developing brain by means of axon guidance molecules. Intermediate targets producing such signal molecules are used as guideposts to find distal targets. Glial, and sometimes neuronal, midline structures represent intermediate targets when axons cross the midline to reach the contralateral hemisphere. The subcommissural organ (SCO), a specialized neuroepithelium located at the dorsal midline underneath the posterior commissure, releases SCO-spondin, a large glycoprotein belonging to the thrombospondin superfamily that shares molecular domains with axonal pathfinding molecules. Several evidences suggest that the SCO could be involved in the development of the PC. First, both structures display a close spatiotemporal relationship. Second, certain mutants lacking an SCO present an abnormal PC. Third, some axonal guidance molecules are expressed by SCO cells. Finally, SCO cells, the Reissner's fiber (the aggregated form of SCO-spondin), or synthetic peptides from SCO-spondin affect the neurite outgrowth or neuronal aggregation in vitro. PMID:22559938

Grondona, Jesús M; Hoyo-Becerra, Carolina; Visser, Rick; Fernández-Llebrez, Pedro; López-Ávalos, María Dolores

2012-01-01

396

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

2014-01-01

397

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:25006043

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

2014-07-01

398

Phase II trial design with Bayesian adaptive randomization and predictive probability

Summary We propose a randomized phase II clinical trial design based on Bayesian adaptive randomization and predictive probability monitoring. Adaptive randomization assigns more patients to a more efficacious treatment arm by comparing the posterior probabilities of efficacy between different arms. We continuously monitor the trial by using the predictive probability. The trial is terminated early when it is shown that one treatment is overwhelmingly superior to others or that all the treatments are equivalent. We develop two methods to compute the predictive probability by considering the uncertainty of the sample size of the future data. We illustrate the proposed Bayesian adaptive randomization and predictive probability design by using a phase II lung cancer clinical trial, and we conduct extensive simulation studies to examine the operating characteristics of the design. By coupling adaptive randomization and predictive probability approaches, the trial can treat more patients with a more efficacious treatment and allow for early stopping whenever sufficient information is obtained to conclude treatment superiority or equivalence. The design proposed also controls both the type I and the type II errors and offers an alternative Bayesian approach to the frequentist group sequential design. PMID:24259753

Yin, Guosheng; Chen, Nan; Lee, J. Jack

2013-01-01

399

Atomic Transition Probabilities of Aluminum. A Critical Compilation

NASA Astrophysics Data System (ADS)

This compilation is the second in a series of updates to Atomic Transition Probabilities, Sodium through Calcium, published in 1969 by Wiese et al. [Atomic Transition Probabilities, Vol. II, Vol. II: Sodium through Calcium, NSROS-NBS Vol. 2 (U.S. GPO, Washington, D.C., 1969)]. Atomic transition probabilities have been critically evaluated and compiled for about 5000 spectral lines of aluminum (nuclear charge Z =13). The cited values and their estimated uncertainties are based on our consideration of all available theoretical and experimental literature sources. All ionization stages (except for hydrogenic) are covered, and the data are presented in separate tables for each atom and ion. Separate listings are given for "allowed" (electric dipole) and "forbidden" (magnetic dipole plus electric and magnetic quadrupole) transitions. In each spectrum, lines are grouped into multiplets which are arranged in order of ascending lower- and upper-level energies, respectively. For each line, the emission transition probability Aki, the line strength S, and (for allowed lines) the absorption oscillator strength fik are given, together with the spectroscopic designation, the wavelength, the statistical weights, and the energy levels of the lower and upper states. The estimated relative uncertainties of the line strength are also indicated, as are the source citations. We include only those lines whose transition rates are deemed sufficiently accurate to qualify as reference values. Short introductions precede the tables for each ion.

Kelleher, D. E.; Podobedova, L. I.

2008-06-01

400

Equally Likely Outcomes Axioms of Probability Consequences of the Axioms Basics of Probability

Equally Likely Outcomes Axioms of Probability Consequences of the Axioms Topic 5 Basics of Probability Equally Likely Outcomes and the Axioms of Probability 1 / 13 #12;Equally Likely Outcomes Axioms of Probability Consequences of the Axioms Outline Equally Likely Outcomes Axioms of Probability Consequences

Watkins, Joseph C.

401

Magnetic resonance properties of hydrogen: imaging the posterior fossa

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 (T/sub 1/). In the second, an inversion-recovery technique was used to produce images with a stronger dependence on the spin-lattice relaxation time. In the third, a spin-echo technique was used to obtain images with a dependence on the spin-spin relaxation time (T/sub 2/). All three types of NMR image were unaffected by bone artifact. Visualization of brain adjacent to the skull base was obtained without loss of detail due to partial-volume effect from bone. The saturation-recovery images highlighted arteries and veins that were clearly visible without the use of contrast agents. The inversion-recovery images showed remarkable gray-white matter differentiation enabling internal structure to be seen within the brainstem and cerebellum. The trigeminal nerve and ganglion were also seen outside the brain. Experience with the spin-echo technique is limited, but the images at the base of the brain show considerable soft-tissue detail. The NMR images of the posterior fossa in this study were comparable in quality to those obtained from a new rotate-rotate x-ray computed tomography machine and were superior in several respects.

Young, I.R. (Thorn-EMI Ltd., Middlesex, England); Burl, M.; Clarke, G.J.

1981-11-01

402

Posterior Tibial Tendon Dysfunction and Flatfoot: Analysis with Simulated Walking

Many biomechanical studies investigated pathology of flatfoot and effects of operations on flatfoot. The majority of cadaveric studies are limited to the quasistatic response to static joint loads. This study examined the unconstrained joint motion of the foot and ankle during stance phase utilizing a dynamic foot-ankle simulator in simulated stage 2 posterior tibial tendon dysfunction (PTTD). Muscle forces were applied on the extrinsic tendons of the foot using six servo-pneumatic cylinders to simulate their action. Vertical and fore-aft shear forces were applied and tibial advancement was performed with the servomotors. Three-dimensional movements of multiple bones of the foot were monitored with a magnetic tracking system. Twenty-two fresh-frozen lower extremities were studied in the intact condition, then following sectioning peritalar constraints to create a flatfoot and unloading the posterior tibial muscle force. Kinematics in the intact condition were consistent with gait analysis data for normals. There were altered kinematics in the flatfoot condition, particularly in coronal and transverse planes. Calcaneal eversion relative to the tibia averaged 11.1±2.8° compared to 5.8±2.3° in the normal condition. Calcaneal-tibial external rotation was significantly increased in flatfeet from mean of 2.3±1.7° to 8.1±4.0°. There were also significant changes in metatarsal-tibial eversion and external rotation in the flatfoot condition. The simulated PTTD with flatfoot was consistent with previous data obtained in patients with PTTD. The use of a flatfoot model will enable more detailed study on the flatfoot condition and/or effect of surgical treatment. PMID:22939754

Watanabe, Kota; Kitaoka, Harold B.; Fujii, Tadashi; Crevoisier, Xavier M.; Berglund, Lawrence J.; Zhao, Kristin D.; Kaufman, Kenton R.; An, Kai-Nan

2012-01-01

403

Regional Variations in Mechanical Strain in the Posterior Human Sclera

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

2012-01-01

404

Growth patterns in Onychophora (velvet worms): lack of a localised posterior proliferation zone

Background During embryonic development of segmented animals, body segments are thought to arise from the so-called "posterior growth zone" and the occurrence of this "zone" has been used to support the homology of segmentation between arthropods, annelids, and vertebrates. However, the term "posterior growth zone" is used ambiguously in the literature, mostly referring to a region of increased proliferation at the posterior end of the embryo. To determine whether such a localised posterior proliferation zone is an ancestral feature of Panarthropoda (Onychophora + Tardigrada + Arthropoda), we examined cell division patterns in embryos of Onychophora. Results Using in vivo incorporation of the DNA replication marker BrdU (5-bromo-2'-deoxyuridine) and anti-phospho-histone H3 immunolabelling, we found that a localised posterior region of proliferating cells does not occur at any developmental stage in onychophoran embryos. This contrasts with a localised pattern of cell divisions at the posterior end of annelid embryos, which we used as a positive control. Based on our data, we present a mathematical model, which challenges the paradigm that a localised posterior proliferation zone is necessary for segment patterning in short germ developing arthropods. Conclusions Our findings suggest that a posterior proliferation zone was absent in the last common ancestor of Onychophora and Arthropoda. By comparing our data from Onychophora with those from annelids, arthropods, and chordates, we suggest that the occurrence of a "posterior growth zone" currently cannot be used to support the homology of segmentation between these three animal groups. PMID:21050428

2010-01-01

405

Complete absence of the posterior arch of C1: Case report

Posterior atlas arch anomalies are relatively common, but have a variety of presentations ranging from partial clefts to complete agenesis of the posterior arch. Partial clefts are prevalent in 4% of patients and are generally asymptomatic. However, complete agenesis of the posterior arch is extremely rare. We report the case of a 46-year-old man who presented with upper cervical spine and occipital pain as well as left sided headaches. Imaging revealed congenital complete absence of the posterior arch of C1 (Type E) without any radiographic evidence of instability. We discuss our case in light of other reported cases and detail its management.

Khanna, R.; Smith, Z. A.; Dlouhy, B. J.; Dahdaleh, N. S

2014-01-01

406

Locked bilateral posterior fracture-dislocation of the shoulder in an epileptic patient: case report

Bilateral posterior dislocation of the shoulder, often secondary to seizures, is uncommon, while bilateral posterior fracture-dislocations is rarer still: 0.6 cases among a population of 100,000 people per year. The scientific literature contains very few published reports of cases of bilateral posterior fracture-dislocation of the shoulder, a condition that tends to be sustained by epileptic patients during seizures. The authors presented a case of bilateral posterior fracture-dislocation of the shoulder secondary to a first epileptic seizure episode treated by humeral head replacement with stem less implants on both shoulders, with satisfactory radiographic and clinical outcome.

CAUTERO, ENRICO; GERVASI, ENRICO

2014-01-01

407

Modeling Prostate Cancer Detection Probability, with Applications

investigating causes and treatments. Robert Serfling Modeling Prostate Cancer Detection Probability cancer present as well as tumor nodule sizes, to judge clinical significance before treatment selectionModeling Prostate Cancer Detection Probability, with Applications Robert Serfling1 University

Serfling, Robert

408

The Probability Distribution for a Biased Spinner

ERIC Educational Resources Information Center

This article advocates biased spinners as an engaging context for statistics students. Calculating the probability of a biased spinner landing on a particular side makes valuable connections between probability and other areas of mathematics. (Contains 2 figures and 1 table.)

Foster, Colin

2012-01-01

409

Belief, Uncertainty, and Probability Jan van Eijck

]. #12;Probability, Betting, Ignorance #12;Probability, Betting, Ignorance Christiaan Huygens, 1629Â1695 #12;Van Rekeningh in Spelen van Geluck 1660 [Huy60] #12;#12;Huygens' Proposal for the Foundations

van Eijck, Jan

410

Accurate Guitar Tuning by Cochlear Implant Musicians

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

2014-01-01

411

Accurate guitar tuning by cochlear implant musicians.

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

2014-01-01

412

Previous application of Maximum Likelihood Bayesian Model Averaging (MLBMA, Neuman [2002, 2003]) to alternative variogram models of log air permeability data in fractured tuff has demonstrated its effectiveness in quantifying conceptual model uncertainty and enhancing predictive capability [Ye et al., 2004]. A question remained how best to ascribe prior probabilities to competing models. In this paper we examine the extent to which lead statistics of posterior log permeability predictions are sensitive to prior probabilities of seven corresponding variogram models. We then explore the feasibility of quantifying prior model probabilities by (a) maximizing Shannon's entropy H [Shannon, 1948] subject to constraints reflecting a single analyst's (or a group of analysts?) prior perception about how plausible each alternative model (or a group of models) is relative to others, and (b) selecting a posteriori the most likely among such maxima corresponding to alternative prior perceptions of various analysts or groups of analysts. Another way to select among alternative prior model probability sets, which however is not guaranteed to yield optimum predictive performance (though it did so in our example) and would therefore not be our preferred option, is a min-max approach according to which one selects a priori the set corresponding to the smallest value of maximum entropy. Whereas maximizing H subject to the prior perception of a single analyst (or group) maximizes the potential for further information gain through conditioning, selecting the smallest among such maxima gives preference to the most informed prior perception among those of several analysts (or groups). We use the same variogram models and log permeability data as Ye et al. [2004] to demonstrate that our proposed approach yields the least amount of posterior entropy (residual uncertainty after conditioning) and enhances predictive model performance as compared to (a) the non-informative neutral case in which all prior model probabilities are set equal to each other and (b) an informed case that nevertheless violates the principle of parsimony.

Ye, Ming; Neuman, Shlomo P.; Meyer, Philip D.; Pohlmann, Karl

2005-12-24

413

Compact High-Order Accurate Nonlinear Schemes

We develop here compact high-order accurate nonlinear schemes for discontinuities capturing. Such schemes achieve high-order spatial accuracy by the cell-centered compact schemes. Compact adaptive interpolations of variables at cell edges are designed which automatically “jump” to local ones as discontinuities being encountered. This is the key to make the overall compact schemes capture discontinuities in a nonoscillatory manner. The analysis

Xiaogang Deng; Hiroshi Maekawa

1997-01-01

414

SOPROLIFE System: An Accurate Diagnostic Enhancer

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. PMID:25401161

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

2014-01-01

415

Towards Accurate Modeling of Binary Black Holes

NASA Astrophysics Data System (ADS)

Massive black holes (MBHs) that are believed to reside at the centers of all galaxies with bulges will form a binary and coalesce into each other following a galactic merger. The final stage of MBH binary evolution is a strong source of low frequency gravitational waves for the joint NASA/ESA LISA mission. The merging phase of the coalescence will provide an excellent opportunity to investigate Einstein's theory of general relativity in a strong nonlinear regime. Encouraging progress has been made recently in numerical relativity simulations of orbiting/merging black holes; however a long term and accurate evolution of a realistic situation has yet to be demonstrated. Using mesh refinement techniques, we focus on accurate simulations of the source (merging binary black holes) and accurate extraction of the generated gravitational waves. We study a head-on collision as the first model problem for a thorough validation of our approach. I will discuss some of the issues involved and present recent results.

Choi, Dae-Il; Centrella, Joan; van Meter, Jim; Imbiriba, Breno; Brown, David; Lowe, Lisa

2005-04-01

416

Exploring Probability and the Monte Carlo Method

NSDL National Science Digital Library

This multimedia mathematics resource examines probability. A video illustrates how math is used to evaluate the danger of avalanches in the mountains of Alberta. An interactive component allows students to compare theoretical and experimental probabilities, as well as explore the Monte Carlo method. A probability print activity is also included.

2003-01-01

417

Probability in the Engineering and Informational Sciences

Probability in the Engineering and Informational Sciences http://journals.cambridge.org/PES Additional services for Probability in the Engineering and Informational Sciences: Email alerts: Click here Probability in the Engineering and Informational Sciences / Volume 8 / Issue 02 / April 1994, pp 287 290 DOI

Oren, Shmuel S.

418

POLLOCK ON PROBABILITY IN EPISTEMOLOGY BRANDEN FITELSON

POLLOCK ON PROBABILITY IN EPISTEMOLOGY BRANDEN FITELSON Abstract. John Pollock has done a lot of interesting and important work on the metaphysics and epistemology of probability over several decades of issues addressed in [14] pertain- ing to probability, logic, and epistemology. First, I will discuss some

Fitelson, Branden

419

Characterizing common cause closed probability spaces

in the very strong sense of being embeddable into a common cause closed probability space. These results solveCharacterizing common cause closed probability spaces October 12, 2010 ZalÂ´an Gyenis Department probability measure space was defined in earlier papers [14], [9] to be common cause closed if it contains

420

Relations between entropy and error probability

The relation between the entropy of a discrete random variable and the minimum attainable probability of error made in guessing its value is examined. While Fano's inequality provides a tight lower bound on the error probability in terms of the entropy, the present authors derive a converse result-a tight upper bound on the minimal error probability in terms of the

Meir Feder; Neri Merhav

1994-01-01

421

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

2005-01-01

422

The Black Hole Formation Probability

A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we derive the probability that a star will make a BH as a function of its ZAMS mass, $P_{\\rm BH}(M_{\\rm ZAMS})$. We explore possible biases in the observed BH mass distribution and find that this sample is best suited for studying BH formation in stars with ZAMS masses in the range $12-...

Clausen, Drew; Ott, Christian D

2014-01-01

423

over a set of variables X, a variable X X, and a domain value x D(X), a posterior marginal P(x|e joint probabilities, P(x, e) and P(e): P(x|e) = P(x, e) P(e) (1) Given a set C={C1, ..., Cp} X: P(x|e) = M i=1 P(x|ci , e)P(ci |e) (3) The computation of P(ci, e) for any assignment c = ci

Dechter, Rina

424

Liposarcomas of the posterior mediastinum: clinicopathologic study of 18 cases.

Sarcomas of the posterior mediastinum are rare and correspond mostly to neurogenic tumors. We studied 18 cases of liposarcoma presenting in the posterior mediastinum; because of their unusual location, some of these tumors posed difficulties for diagnosis. There were 11 men and 7 women aged 29-87 years (mean: 57). The tumors were large lobulated masses ranging from 6 to 30?cm in greatest diameter (median: 15?cm). Symptoms included cough, dysphagia, and chest pain. Four patients were asymptomatic and the tumors were discovered incidentally on chest X-rays. Histologically, 10/18 (55%) cases were atypical lipomatous tumor/well-differentiated liposarcoma, one of which harbored a smooth muscle component (lipoleiomyosarcoma); 3/18 (16%) were de-differentiated liposarcoma, one of which also harbored a smooth muscle component; 3/18 (16%) were myxoid/round cell liposarcoma; and 2/18 (11%) were pleomorphic liposarcoma. The cases of well-differentiated liposarcoma were mostly of the sclerosing type; however, five of them also showed prominent myxoid stroma closely resembling myxoid liposarcoma. Immunohistochemistry was performed in selected cases; 4/8 cases tested showed focal positivity for S-100 protein and 5/8 cases showed nuclear positivity for MDM-2. The three cases of myxoid liposarcoma were all negative for MDM2. Both cases of lipoleiomyosarcoma showed positivity for SMA and desmin in the smooth muscle component. FISH was performed in two cases of well-differentiated liposarcoma and high levels of amplification of MDM2 at 12q13-15 were observed; the CHOP translocation at 12q13.1-q13.2 was absent in both cases. Complete surgical excision was performed in 11 cases; however, negative surgical margins were achieved only in four. Clinical follow-up ranging from 1 to 192 months (median 28 months) was available for 13 patients. Two patients with myxoid/round cell liposarcoma died of tumor after 4 months and 3 years, respectively. Both had widely disseminated metastatic disease at the time of death. Six patients (6/10) with well-differentiated liposarcoma were alive and well with no evidence of disease (at 4, 7, 12, 15, and 25 months) and three (3/10) were alive with disease (at 3, 4, and 6 months). One patient with well-differentiated liposarcoma had multiple recurrences and a liver metastasis after 14 years; however, the patient was alive and well at 16 years. Five patients were lost to follow-up. In general, the biologic behavior of liposarcomas in the posterior mediastinum seems to correlate well with the histologic subtype and mirrors that of their counterpart in the retroperitoneum.Modern Pathology advance online publication, 5 December 2014; doi:10.1038/modpathol.2014.152. PMID:25475695

Ortega, Pablo; Suster, David; Falconieri, Giovanni; Zambrano, Eduardo; Moran, Cesar A; Morrison, Carl; Suster, Saul

2014-12-01

425

Motivation: A plethora of alignment tools have been created that are designed to best fit different types of alignment conditions. While some of these are made for aligning Illumina Sequence Analyzer reads, none of these are fully utilizing its probability (prb) output. In this article, we will introduce a new alignment approach (Slider) that reduces the alignment problem space by utilizing each read base's probabilities given in the prb files. Results: Compared with other aligners, Slider has higher alignment accuracy and efficiency. In addition, given that Slider matches bases with probabilities other than the most probable, it significantly reduces the percentage of base mismatches. The result is that its SNP predictions are more accurate than other SNP prediction approaches used today that start from the most probable sequence, including those using base quality. Contact: nmalhis@bcgsc.ca Supplementary information and availability: http://www.bcgsc.ca/platform/bioinfo/software/slider PMID:18974170

Malhis, Nawar; Butterfield, Yaron S. N.; Ester, Martin; Jones, Steven J. M.

2009-01-01

426

Bell as the Copernicus of Probability

Our aim is to emphasize the role of mathematical models in physics, especially models of geometry and probability. We briefly compare developments of geometry and probability by pointing to similarities and differences: from Euclid to Lobachevsky and from Kolmogorov to Bell. In probability Bell played the same role as Lobachevsky in geometry. In fact, violation of Bell's inequality implies the impossibility to apply the classical probability model of Kolmogorov (1933) to quantum phenomena. Thus quantum probabilistic model (based on Born's rule) is an example of non-Kolmogorovian model of probability, similarly to the Lobachevskian model -- the first example of non-Euclidean model of geometry. We also discuss coupling of the classical probabilistic model with classical (Boolean) logic. The Kolmogorov model of probability is based on the set-theoretic presentation of the Boolean logic. In this framework violation of Bell's inequality implies the impossibility to use the Boolean structure of events for quantum phenomena; instead of it, events have to be represented by linear subspaces. This is the "probability model" interpretation of violation of Bell's inequality. We also criticize the standard interpretation -- an attempt to add to rigorous mathematical probability models additional elements such as (non)locality and (un)realism. Finally, we compare embeddings of non-Euclidean geometries into the Euclidean space with embeddings of the non-Kolmogorovian probabilities (in particular, quantum probability) into the Kolmogorov probability space. As an example, we consider the CHSH-test.

Andrei Khrennikov

2014-12-22

427

The Black Hole Formation Probability

NASA Astrophysics Data System (ADS)

A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH(M ZAMS). Although we find that it is difficult to derive a unique P BH(M ZAMS) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH(M ZAMS) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH(M ZAMS) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

2015-02-01

428

Complete removal of the posterior hyaloid is an important procedure in vitrectomy for various vitreoretinal disorders. Although posterior vitreous detachment (PVD) can be usually induced by active aspiration of vitreous gel, it is difficult in cases where the posterior hyaloid attaches tightly to the retina, especially in minimum incision vitrectomy systems (MIVS) due to the smaller apertures of the instruments. We describe a novel technique of creating PVD without aspiration. In this method, a break in the vitreous cortex is initially made at the posterior precortical vitreous pocket using a diamond dusted membrane scraper. Once a break in the vitreous cortex is induced, the break is extended by continuing the same manipulation. Detachment of the posterior vitreous gradually progresses by the influx of irrigation fluid from the break into the space between the posterior vitreous and the retina. Subsequently, the scraper is inserted under the detached posterior hyaloid from the break in the cortical vitreous, and is lifted upward to complete the PVD. Complete PVD is confirmed by observation of the Weiss ring in front of the retina. Using this technique, PVD can be achieved in vitrectomies using MIVS, even when the posterior hyaloid attaches tightly to the retina. PMID:22976586

Takeuchi, Masaru; Takayama, Kei; Sato, Tomohito; Ishikawa, Syo; Fujii, Sayuri; Sakurai, Yutaka

2012-11-01

429

Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images. PMID:24762835

Cunningham, Brian; Jackson, Kelly; Ortega, Gil

2014-04-01

430

PURPOSE: This study reports outcomes of phacoemulsification cataract extraction and posterior chamber intraocular lens implantation within the capsular bag in patients with uveitis.METHODS: We retrospectively reviewed the charts of 32 patients (39 eyes) with uveitis who underwent phacoemulsification cataract extraction and posterior chamber intraocular lens implantation by two surgeons at The Cleveland Clinic Foundation from January 1990 to June 1998.

Marc F. G Estafanous; Careen Y Lowder; David M Meisler; Ranjana Chauhan

2001-01-01

431

Traumatic bilateral posterior hip dislocation in 10 year old male child

Traumatic bilateral posterior hip dislocation in skeletally immature patient is reported very less in literature. We report a 10 yr old boy presented to us following farmyard injury with bilateral posterior hip dislocation, which was reduced manually under sedation with uneventful follow-up and complete hip range of motion at 2 year.

Garg, Vipul; Singh, Ajay Pal; Singh, Arun Pal; Bajaj, P.S.

2014-01-01

432

Posterior cingulate cortex activation by emotional words: fMRI evidence from a valence decision task

Functional imaging studies consistently find that emotional stimuli activate the posterior cingulate cortex, a region that appears to have memory-related functions. However, prior imaging studies have not controlled for non-emotional stimulus features that might activate this region by engaging memory processes unrelated to emotion. This study examined whether emotional words activated the posterior cingulate cortex when these potentially confounding factors

Richard J. Maddock; Amy S. Garrett; Michael H. Buonocore

2003-01-01

433

Metachronous Bilateral Posterior Tibial Artery Aneurysms in Ehlers-Danlos Syndrome Type IV

Ehlers-Danlos syndrome type IV is a life-threatening genetic connective tissue disorder. We report a 24-year-old woman with EDS-IV who presented with metachronous bilateral aneurysms/pseudoaneurysms of the posterior tibial arteries 15 months apart. Both were treated successfully with transarterial coil embolization from a distal posterior tibial approach.

Hagspiel, Klaus D., E-mail: kdh2n@virginia.edu [University of Virginia, Department of Radiology (United States); Bonatti, Hugo [Vanderbilt University, Department of Surgery (United States); Sabri, Saher [University of Virginia, Department of Radiology (United States); Arslan, Bulent [Moffitt Cancer Center (United States); Harthun, Nancy L. [Johns Hopkins University, Division of Vascular Surgery, Department of Surgery (United States)

2011-04-15

434

Isolated posterior uveal effusion: expanding the spectrum of the uveal effusion syndrome

Uveal effusion syndrome usually causes peripheral chorioretinal detachment, but posterior effusion may present as isolated macular edema with serous macular detachment in the setting of hyperopia and a thickened posterior choroid. Carbonic anhydrase inhibitors may be effective to treat this condition. PMID:25565767

Pautler, Scott E; Browning, David J

2015-01-01

435

Isolated posterior uveal effusion: expanding the spectrum of the uveal effusion syndrome.

Uveal effusion syndrome usually causes peripheral chorioretinal detachment, but posterior effusion may present as isolated macular edema with serous macular detachment in the setting of hyperopia and a thickened posterior choroid. Carbonic anhydrase inhibitors may be effective to treat this condition. PMID:25565767

Pautler, Scott E; Browning, David J

2015-01-01

436

Heparin drug delivery system for prevention of posterior capsular opacification in rabbit eyes

Background. The aim of this study was to investigate the safety and efficacy of a heparin drug delivery system (HEP DDS) for prevention of posterior capsular opacification (PCO) in rabbits. Methods. Fifty New Zealand albino rabbits (50 eyes) undergoing phacoemulsification were equally divided into five groups receiving normal saline eye drops (group A), a carrier DDS implanted into the posterior

Lixin Xie; Jie Sun; Zhan Yao

2003-01-01

437

) posterior intestine Ilan M. Ruhr,1 Charlotte Bodinier,1 Edward M. Mager,1 Andrew J. Esbaugh,1 Cameron toadfish (Opsanus beta) posterior intestine. Am J Physiol Regul Integr Comp Physiol 307: R1167ÂR1179, 2014 (GN) and uroguanylin (UGN) on fluid and electrolyte transport in the teleost fish intestine have yet

Grosell, Martin

438

Summary: The effect of endovascular treatment on the re- covery of neural function in patients with third nerve palsy caused by an aneurysm of the posterior communicating ar- tery is poorly documented. We report three cases in which third nerve paresis resolved completely within 2 to 3 weeks of endovascular occlusion of a posterior communicating artery aneurysm. The recovery of

Daniel Birchall; Makhan S. Khangure; William McAuliffe

439

Object The purpose of the present study is to assess the effectiveness of endoscopic third ventriculostomy (ETV) in children with hydrocephalus related to posterior fossa tumors. Methods Between September 1999 and December 2002, 63 children with posterior fossa tumors were treated at Santobono Hospital in Naples, Italy. Twenty-six patients had severe hydrocephalus. In order to relieve intracranial hypertension before tumor

Claudio Ruggiero; Giuseppe Cinalli; Pietro Spennato; Ferdinando Aliberti; Emilio Cianciulli; Vincenzo Trischitta; Giuseppe Maggi

2004-01-01

440

Evaluating the Accuracy of Sampling-Based Approaches to the Calculation of Posterior Moments

Data augmentation and Gibbs sampling are two closely related, sampling-based approaches to the calculation of posterior moments. The fact that each produces a sample whose constituents are neither independent nor identically distributed complicates the assessment of convergence and numerical accuracy of the approximations to the expected value of functions of interest under the posterior. In this paper methods from spectral

John Geweke

1992-01-01

441

Bilateral macular folds as a diagnostic clue to late-presenting posterior microphthalmos.

Posterior microphthalmos with macular folds is a very uncommon condition. We report such an unusual late-presenting case of posterior microphthalmos where macular folds uncovered the diagnosis and discuss the possibility of worsening of macular folds with advancing age. PMID:23947423

Takkar, Brijesh; Bhatia, Indrish; Chandra, Parijat; Ganguly, Anasua; Azad, Rajvardhan

2014-05-01

442

Teaching of direct posterior resin composite restorations in UK dental therapy training programmes

Aim With the numbers of dental therapists involved in the delivery of dental care within the UK on the increase, and the trend towards the use of direct resin composites (composites) for the restoration of posterior teeth, this study was undertaken to describe the teaching of posterior composites in dental therapy training programmes in the UK. A secondary aim was

N. H. F. Wilson; C. D. Lynch

2010-01-01

443

Testing the accuracy of Verbal Probability Scale for predicting short -term brand choice

In this research the predictive accuracy of the Verbal Probability Scale (VPS) in predicting four-week brand choice was compared to benchmarks from prior research and past behaviour. The results show that the measure of past behaviour provided the most accurate predictions at both brand and individual level. The exception to this was for the smallest brand in the market, where

Jenni Romaniuk

2004-01-01

444

The concept of canopy spectral invariants expresses the observation that simple algebraic combinations of leaf and canopy spectral reflectance become wavelength independent and determine two canopy structure specific variables - the recollision and escape probabilities. These variables specify an accurate relationship between the spectral response of a vegetation canopy to incident solar radiation at the leaf and the canopy scale.

L. Xu; M. A. Schull; A. Samanta; R. B. Myneni; Y. Knyazikhin

2010-01-01

445

Accurate upwind methods for the Euler equations

NASA Technical Reports Server (NTRS)

A new class of piecewise linear methods for the numerical solution of the one-dimensional Euler equations of gas dynamics is presented. These methods are uniformly second-order accurate, and can be considered as extensions of Godunov's scheme. With an appropriate definition of monotonicity preservation for the case of linear convection, it can be shown that they preserve monotonicity. Similar to Van Leer's MUSCL scheme, they consist of two key steps: a reconstruction step followed by an upwind step. For the reconstruction step, a monotonicity constraint that preserves uniform second-order accuracy is introduced. Computational efficiency is enhanced by devising a criterion that detects the 'smooth' part of the data where the constraint is redundant. The concept and coding of the constraint are simplified by the use of the median function. A slope steepening technique, which has no effect at smooth regions and can resolve a contact discontinuity in four cells, is described. As for the upwind step, existing and new methods are applied in a manner slightly different from those in the literature. These methods are derived by approximating the Euler equations via linearization and diagonalization. At a 'smooth' interface, Harten, Lax, and Van Leer's one intermediate state model is employed. A modification for this model that can resolve contact discontinuities is presented. Near a discontinuity, either this modified model or a more accurate one, namely, Roe's flux-difference splitting. is used. The current presentation of Roe's method, via the conceptually simple flux-vector splitting, not only establishes a connection between the two splittings, but also leads to an admissibility correction with no conditional statement, and an efficient approximation to Osher's approximate Riemann solver. These reconstruction and upwind steps result in schemes that are uniformly second-order accurate and economical at smooth regions, and yield high resolution at discontinuities.

Huynh, Hung T.

1993-01-01

446

How Accurate Are Student-Collected Data?

NSDL National Science Digital Library

The purpose of this study was to teach upper elementary and high school students to monitor two estuarine creeks using an adaptation of the Georgia Department of Natural Resources Adopt-A-Stream protocol. Data collected by students were then compared to data collected by a trained instructor to determine the accuracy of student-collected data for dissolved-oxygen (DO) concentration, salinity, and water temperature. Results of the study revealed that students can collect accurate data for several water-quality parameters, and these data can be presented to the community to assist in making informed decisions regarding environmental issues.

Mary Carla Curran

2008-04-01

447

Accurate and universal delineation of prokaryotic species.

The exponentially increasing number of sequenced genomes necessitates fast, accurate, universally applicable and automated approaches for the delineation of prokaryotic species. We developed specI (species identification tool; http://www.bork.embl.de/software/specI/), a method to group organisms into species clusters based on 40 universal, single-copy phylogenetic marker genes. Applied to 3,496 prokaryotic genomes, specI identified 1,753 species clusters. Of 314 discrepancies with a widely used taxonomic classification, >62% were resolved by literature support. PMID:23892899

Mende, Daniel R; Sunagawa, Shinichi; Zeller, Georg; Bork, Peer

2013-09-01

448

The first accurate description of an aurora

NASA Astrophysics Data System (ADS)

As technology has advanced, the scientific study of auroral phenomena has increased by leaps and bounds. A look back at the earliest descriptions of aurorae offers an interesting look into how medieval scholars viewed the subjects that we study.Although there are earlier fragmentary references in the literature, the first accurate description of the aurora borealis appears to be that published by the German Catholic scholar Konrad von Megenberg (1309-1374) in his book Das Buch der Natur (The Book of Nature). The book was written between 1349 and 1350.

Schröder, Wilfried

2006-12-01

449

Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia. PMID:24817750

Kükner, A ?ahap; Alagöz, Gürsoy; Erdurmu?, Mesut; Serin, Didem; Do?an, Ümit; Y?lmaz, Turgut

2014-01-01

450

Posterior reversible encephalopathy syndrome in children with kidney disease.

Posterior reversible encephalopathy syndrome (PRES) is a clinic-radiographic entity of heterogeneous etiologies that are grouped together because of similar findings on neuro-imaging and associated symptom complex of headache, vision loss, altered mentation, and seizures. Although usually considered benign and reversible, characteristics of this syndrome in pediatric patients remain obscure. This case series included 11 patients (8 males, 3 females, age 3-15 years) of PRES during September 2010 to February 2012 out of a total 660 renal pediatric patients (1.66%). We studied their clinical profile, contributory factors, and outcome. Presenting symptoms were headache in 73%, dimness of vision or cortical blindness in 36%, seizures in 91%, and altered mentation in 55%. The associated renal diseases were acute renal failure (55%), chronic renal failure (9%), and 36% had normal renal function. The contributory factors were uncontrolled hypertension (100%), severe hypoproteinemia (9%), persistent hypocalcemia (9%), hemolytic uremic syndrome (36%), cyclosporine toxicity (9%), lupus nephritis (9%), high hematocrit (9%), and pulse methylprednisolone (9%). Brain imaging showed involvement of occipito-parietal area (100%) and other brain areas (63%). All but one patient of hemolytic uremic syndrome had complete clinical neurological recovery in a week, and all had normal neurological imaging after 4-5 weeks. PRES is an underdiagnosed entity in pediatric renal disease patients. Associated hypertension, renal disease, and immunosuppressive treatment are important triggers. Early diagnosis and treatment of comorbid conditions is of prime importance for early reversal of syndrome. PMID:24574628

Gera, D N; Patil, S B; Iyer, A; Kute, V B; Gandhi, S; Kumar, D; Trivedi, H L

2014-01-01

451

[Periorbital hematoma as a complication of posterior peribulbar anesthesia].

We report a case of a large periorbital hematoma which furtherly extended to the ipsilateral orbit and appeared after posterior peribulbar blockade in a 70-year-old woman undergoing cataract extraction and intraocular implant. Peribulbar blockade was carried out with a 23-gauge blunt bevel Atkinson's needle introduced at the level of nasal or internal angle of the upper lid without loosing contact with the ceiling of the orbit. Anesthetic solution was bupicavaine at 0.75% with 10 U/ml of hyaluronidase, 3 ml. Usual blockade of lower lid was not carried out as with the first blockade, an almost complete paresis of extraocular muscles together with discrete conjunctival ecchymosis occurred. Ocular compression was conducted with Homan's balloon at 30 mmHg gor 30 minutes. Then, the eyeball was decompressed and a progressive increase of edema with conjunctival hemorrhage becoming bilateral was observed. Coagulation tests were normal. The incidence of conjunctival ecchymosis and palpebral hematoma with such technique ranges from 2% to 9%; it does not represent any intraoperative problem but may difficult surgery. PMID:2098862

Ortiz Soler, M; García Guasch, R; Preciado Mora, M J; Blanco Vargas, D; González Tadeo, M; Vidal López, F

1990-01-01

452

Clinical assessment of postoperative sensitivity in posterior composite restorations.

This incidence of postoperative sensitivity was evaluated in resin-based posterior restorations. Two hundred and ninety-two direct restorations were evaluated in premolars and molars. A total of 143 Class I and 149 Class II restorations (MO/OD and MOD) were placed in patients ranging in age from 30 to 50 years. After the cavity preparations were completed, a rubber dam was placed, and the preparations were restored using a total-etch system (Prime & Bond NT) and a resin-based restorative material (TPH Spectrum). The patients were contacted after 24 hours and 7, 30 and 90 days postoperatively and questioned regarding the presence of sensitivity and the stimuli that triggered that sensitivity. The Chi-square and Fisher's Exact Test were used for statistical analysis. Evaluation at 24 hours after restorative treatment revealed statistically significant differences among the types of cavity preparations restored and the occurrence of postoperative sensitivity (p = 0.0003), with a higher frequency of sensitivity in Class II MOD restorations (26%), followed by Class II MO/DO (15%) and Class I restorations (5%). At 7, 30 and 90 days after restorative treatment, there was a decrease in the occurrence of sensitivity for all groups. The percentage of sensitivity among the groups was not significantly different. This study shows that the occurrence of sensitivity is correlated with the complexity of the restoration. PMID:17910217

Briso, André Luiz Fraga; Mestrener, Sandra Rahal; Delício, Giovana; Sundfeld, Renato Herman; Bedran-Russo, Ana Karina; de Alexandre, Rodrigo Sversut; Ambrosano, Glaucia Maria Bovi

2007-01-01

453

Multisensory perception of action in posterior temporal and parietal cortices

Environmental events produce many sensory cues for identifying the action that evoked the event, the agent that performed the action, and the object targeted by the action. The cues for identifying environmental events are usually distributed across multiple sensory systems. Thus, to understand how environmental events are recognized requires an understanding of the fundamental cognitive and neural processes involved in multisensory object and action recognition. Here, we investigated the neural substrates involved in auditory and visual recognition of object-directed actions. Consistent with previous work on visual recognition of isolated objects, visual recognition of actions, and recognition of environmental sounds, we found evidence for multisensory audiovisual event-selective activation bilaterally at the junction of the posterior middle temporal gyrus and the lateral occipital cortex, the left superior temporal sulcus, and bilaterally in the intraparietal sulcus. The results suggest that recognition of events through convergence of visual and auditory cues is accomplished through a network of brain regions that was previously implicated only in visual recognition of action. PMID:21036183

James, Thomas W.; VanDerKlok, Ross M.; Stevenson, Ryan A.; James, Karin Harman

2010-01-01

454

Laser light passage through restored and carious posterior teeth.

Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty-two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio-bucco-lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one-third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF. PMID:24750450

Chandler, N P; Pitt Ford, T R; Monteith, B D

2014-08-01

455

A novel function for Egr4 in posterior hindbrain development

Segmentation of the vertebrate hindbrain is an evolutionarily conserved process. Here, we identify the transcription factor early growth response 4 (egr4) as a novel regulator of posterior hindbrain development in Xenopus. egr4 is specifically and transiently expressed in rhombomeres 5 and 6 (r5/r6), and Egr4 knockdown causes a loss of mafb/kreisler and krox20/egr2 expression in r5/r6 and r5, respectively. This phenotype can be fully rescued by injection of frog or mouse Egr4 mRNA. Moreover Egr4-depleted embryos exhibit a specific loss of the neural crest stream adjacent to r5, and have inner ear defects. While the homeodomain protein vHnf1/Hnf1b directly activates Mafb and Krox20 expression in the mouse hindbrain to specify r5, we show that in Xenopus this process is indirect through the activation of Egr4. We provide evidence that rearrangements in the regulatory sequences around egr4 and mafb genes may account for this difference. PMID:25583070

Bae, Chang-Joon; Jeong, Juhee; Saint-Jeannet, Jean-Pierre

2015-01-01

456

[Posterior sternoclavicular dislocation: diagnosis initially easy to miss].

Posterior sternoclavicular (SC) dislocation is a rare diagnosis, which tends to be missed initially. Here we report two cases of a dislocated SC joint: one left and one right. The first case describes a 25-year-old male who sustained a direct injury caused by his seatbelt during a car accident. The diagnosis was made 3 months after the initial trauma following performance of a CT scan. His left SC joint was stabilized using a hamstring tendon allograft. The second patient, a 55-year-old female, sustained an indirect injury following a fall onto her right shoulder. The diagnosis was made 6 weeks after the trauma had occurred. Her SC joint was also stabilized using a tendon allograft reconstruction. The clinical outcome of both cases was very satisfactory. Better diagnostics - more attention for subtle symptoms during physical examination, the right choice of imaging (CT scan) and meticulous following of Advanced Trauma Life Support (ATLS) protocols - could diminish the number of delayed diagnoses in this rare but potentially dangerous injury. PMID:23657099

Jaspars, Kjell C C J; Vuylsteke, Kristien; Peeters, Jef; Declercq, Geert; Verborgt, Oliver

2013-01-01

457

A new technique for Nd:YAG laser posterior capsulotomy

AIM To investigate the effects of a new opening pattern in neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy on visual function. METHODS This technique was conducted along a circular pattern. The energy ranged between 0.8 and 1.2 mJ/pulse was consumed and mean total energy levels were 74±21 mJ (mean±standard deviation: SD, from 40 to 167) and laser shots aimed at 150 µm away behind a datum point and went along an imaginary line which extends 0.5 mm inside from optic margin and into the circular en bloc pattern. Vitreous stands were attached with fragment and then they were cut off by the laser after circular application. The circular fragment was completely separated from vitreous, and then this fragment was quickly sunk in intravitreal space. RESULTS The follow-up period ranges from at least a week to 40mo, making 15.8mo on average. The procedural outcome showed 96% (74 eyes out of the 77 eyes) enhancement in patients' visual acuity. Cystoid macular edema or retinal detachment was not observed in any of the patients during follow-up periods. CONCLUSION This new technique is expected to improve the weaknesses that the conventional procedures have by adding the process to cut off vitreous stands attached with the fragment by the laser to the circular application. PMID:24790883

Min, Jung Kee; An, Jae Hwan; Yim, Jin Ho

2014-01-01

458

Posterior implants for distal extension removable prostheses: a retrospective study.

Common complaints associated with the Kennedy Class I (bilateral free end) and Class II (unilateral free end) removable partial denture situations are lack of stability, minimal retention, and unesthetic retentive clasping. Some of the same complaints have been reported for implant overdentures with only anterior implants. Starting in 1995, 10 of these patients were treated at the University of Washington with posterior osseointegrated implants to provide stability and/or retention of the removable prostheses, eliminating the need for clasps when possible. This article describes implant alternatives and prosthesis designs and presents a follow-up clinical evaluation of at least 1 year consisting of patient satisfaction, radiographic examination, and soft tissue health. Two groups were evaluated. Group 1 included patients whose implants were used as vertical stops for mandibular distal extension prostheses. Care was taken to ensure that the implants were not loaded laterally by creating a single-point contact at the center of a modified healing abutment. In these cases, sufficient retention was available from the anterior teeth and/or implant abutments. Group 2 included patients whose implants required retention because of lack of adequate tooth abutments. In those cases, a resilient type of attachment was used, which allowed for a small divergence from the path of insertion. Results indicated consistent increased satisfaction in all patients, minimal component wear, no radiographic evidence of excessive bone loss, and stable peri-implant soft tissues. PMID:12956479

Mitrani, Ricardo; Brudvik, James S; Phillips, Keith M

2003-08-01

459

Permanent Oviduct Posteriorization after Neonatal Exposure to the Phytoestrogen Genistein

Background: Preimplantation embryo loss during oviduct transit has been observed in adult mice after a 5-day neonatal exposure to the phytoestrogen genistein (Gen; 50 mg/kg/day). Objective: We investigated the mechanisms underlying the contribution of the oviduct to infertility. Methods: Female mice were treated on postnatal days 1–5 with corn oil or Gen (50 mg/kg/day). We compared morphology, gene expression, and protein expression in different regions of the reproductive tracts of Gen-treated mice with those of control littermates at several time points. Results: Neonatal Gen treatment resulted in substantial changes in expression of genes that modulate neonatal oviduct morphogenesis, including Hoxa (homeobox A cluster), Wnt (wingless-related MMTV integration site), and hedgehog signaling genes. An estrogen receptor antagonist blocked these effects, indicating that they were induced by the estrogenic activity of Gen. Oviducts of adults treated neonatally with Gen had abnormal morphology and were stably “posteriorized,” as indicated by altered Hoxa gene patterning during the time of treatment and dramatic, permanent up-regulation of homeobox genes (e.g., Pitx1, Six1) normally expressed only in the cervix and vagina. Conclusions: Neonatal exposure to estrogenic environmental chemicals permanently disrupts oviduct morphogenesis and adult gene expression patterns, and these changes likely contribute to the infertility phenotype. PMID:21810550

Jefferson, Wendy N.; Padilla-Banks, Elizabeth; Phelps, Jazma Y.; Gerrish, Kevin E.

2011-01-01

460

Intramuscular nerve distribution pattern in the human tibialis posterior muscle.

The human tibialis posterior muscle (TPM) has developed to maintain the foot arches for adopting bipedal locomotion. The insertion tendon of this muscle is U-shaped in a cross section, and the fibular part of the muscle whose muscle fibers originated from the fibula has a unique architecture. To understand the developmental history of the human TPM, distribution pattern of intramuscular nerves was investigated in ten sides of eight cadavers. Muscular branches entering the TPM could be classified into five types according to the distribution pattern in the muscle. The nerves innervating the part deeper to the insertion tendon ran transversely in the medial direction toward the tibia. Muscular branches innervating the fibular part ran medioinferiorly, and in four cases had communicating rami with the nerve innervating the other parts of this muscle. Muscular branches innervating the superficial layer whose muscle bundles originated from the tibia ran laterally toward the fibula. These results suggest that the fibular part might develop from the common primordium of the TPM, and the deeper layer of the muscle might expand laterally during the development to acquire a new attaching space on the interosseous membrane and fibula. The superficial layer might also develop laterally to acquire the additional attaching spaces on the fascia of the flexor digitorum longus muscle and flexor hallucis longus muscle, thus the insertion tendon might become U-shaped. With these measures, the TPM might be able to increase muscle volume to yield stronger power. PMID:24791909

Tsutsumi, Masahiro; Arakawa, Takamitsu; Terashima, Toshio; Miki, Akinori

2015-03-01

461

Spectral and temporal processing in rat posterior auditory cortex.

The rat auditory cortex is divided anatomically into several areas, but little is known about the functional differences in information processing between these areas. To determine the filter properties of rat posterior auditory field (PAF) neurons, we compared neurophysiological responses to simple tones, frequency modulated (FM) sweeps, and amplitude modulated noise and tones with responses of primary auditory cortex (A1) neurons. PAF neurons have excitatory receptive fields that are on average 65% broader than A1 neurons. The broader receptive fields of PAF neurons result in responses to narrow and broadband inputs that are stronger than A1. In contrast to A1, we found little evidence for an orderly topographic gradient in PAF based on frequency. These neurons exhibit latencies that are twice as long as A1. In response to modulated tones and noise, PAF neurons adapt to repeated stimuli at significantly slower rates. Unlike A1, neurons in PAF rarely exhibit facilitation to rapidly repeated sounds. Neurons in PAF do not exhibit strong selectivity for rate or direction of narrowband one octave FM sweeps. These results indicate that PAF, like nonprimary visual fields, processes sensory information on larger spectral and longer temporal scales than primary cortex. PMID:17615251

Pandya, Pritesh K; Rathbun, Daniel L; Moucha, Raluca; Engineer, Navzer D; Kilgard, Michael P

2008-02-01

462

Torque control during lingual anterior retraction without posterior appliances

Objective To evaluate the factors that affect torque control during anterior retraction when utilizing the C-retractor with a palatal miniplate as an exclusive source of anchorage without posterior appliances. Methods The C-retractor was modeled using a 3-dimensional beam element (0.9-mm-diameter stainless-steel wire) attached to mesh bonding pads. Various vertical heights and 2 attachment positions for the lingual anterior retraction hooks (LARHs) were evaluated. A force of 200 g was applied from each side hook of the miniplate to the splinted segment of 6 or 8 anterior teeth. Results During anterior retraction, an increase in the LARH vertical height increased the amount of lingual root torque and intrusion of the incisors. In particular, with increasing vertical height, the tooth displacement pattern changed from controlled tipping to bodily displacement and then to lingual root displacement. The effects were enhanced when the LARH was located between the central and lateral incisors, as compared to when the LARH was located between the lateral incisors and canines. Conclusions Three-dimensional lingual anterior retraction of the 6 or 8 anterior teeth can be accomplished using the palatal miniplate as the only anchorage source. Using LARHs at different heights or positions affects the quality of torque and intrusion. PMID:23502971

Mo, Sung-Seo; Sung, Sang-Jin; Chung, Kyu-Rhim; Chun, Yun-Sic; Kook, Yoon-Ah; Nelson, Gerald

2013-01-01

463

Motor features in posterior cortical atrophy and their imaging correlates?

Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by impaired higher visual processing skills; however, motor features more commonly associated with corticobasal syndrome may also occur. We investigated the frequency and clinical characteristics of motor features in 44 PCA patients and, with 30 controls, conducted voxel-based morphometry, cortical thickness, and subcortical volumetric analyses of their magnetic resonance imaging. Prominent limb rigidity was used to define a PCA-motor subgroup. A total of 30% (13) had PCA-motor; all demonstrating asymmetrical left upper limb rigidity. Limb apraxia was more frequent and asymmetrical in PCA-motor, as was myoclonus. Tremor and alien limb phenomena only occurred in this subgroup. The subgroups did not differ in neuropsychological test performance or apolipoprotein E4 allele frequency. Greater asymmetry of atrophy occurred in PCA-motor, particularly involving right frontoparietal and peri-rolandic cortices, putamen, and thalamus. The 9 patients (including 4 PCA-motor) with pathology or cerebrospinal fluid all showed evidence of Alzheimer's disease. Our data suggest that PCA patients with motor features have greater atrophy of contralateral sensorimotor areas but are still likely to have underlying Alzheimer's disease. PMID:25086839

Ryan, Natalie S.; Shakespeare, Timothy J.; Lehmann, Manja; Keihaninejad, Shiva; Nicholas, Jennifer M.; Leung, Kelvin K.; Fox, Nick C.; Crutch, Sebastian J.

2014-01-01

464

Managing complications of posterior spinal instrumentation and fusion.

Complications of posterior spinal instrumentation for adolescent idiopathic scoliosis are often preventable. Preoperative planning helps to minimize intraoperative and postoperative problems. Late recurrence of rotational deformity (crankshaft) in skeletally immature patients can be prevented by adding anterior surgery. Intraoperative complications are minimized by controlled hypotensive anesthesia and sequencing of surgical steps to allow for autocoagulation, reducing blood loss. Use of spinal cord monitoring, Stagnara wakeup test, and careful distraction decreases the risk of neurologic deficit. Good hook-site preparation helps avoid dural tears. The incidence of postoperative pneumothorax and hemothorax is decreased by careful hook attachment, avoiding pleural penetration, judicious use of rib excision thoracoplasty, and roentgenographic verification of central venous pressure line position. Postoperative recommendations include bed position at 30 degrees, frequent log rolling, incentive spirometry, early sitting and standing, early Foley catheter and nasogastric tube removal, prophylactic antibiotics, and prompt attention to wound infections. Postoperative orthotic wear, prescribed exercise, and activity restriction decrease the risk of early instrumentation failure and help correct early postoperative trunk imbalance. The late complications include suspected pseudarthrosis; this should be surgically treated again if there is persistent pain or marked loss of curve correction. PMID:1395301

Wenger, D R; Mubarak, S J; Leach, J

1992-11-01

465

Accurate phase measurement with classical light

In this paper we investigate whether it is in general possible to substitute maximally path-entangled states, namely NOON-states by classical light in a Doppleron-type resonant multiphoton detection processes by studying adaptive phase measurement with classical light. We show that multiphoton detection probability using classical light coincides with that of NOON-states and the multiphoton absorbtion rate is not hindered by the spatially unconstrained photons of the classical light in our scheme. We prove that the optimal phase variance with classical light can be achieved and scales the same as that using NOON-states.

Sabine Wölk; Wenchao Ge; M. Suhail Zubairy

2012-11-13

466

Microsurgical anatomy of the posterior median septum of the human spinal cord.

The aim of this study was to analyze the topographical anatomy of the