Note: This page contains sample records for the topic accurate posterior probability from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results. Last update: August 15, 2014.

Do young children have a basic intuition of posteriorprobability? Do they update their decisions and judgments in the light of new evidence? We hypothesized that they can do so extensionally, by considering and counting the various ways in which an event may or may not occur. The results reported in this paper showed that from the age of five,…

We present a novel, efficient search strategy for large vocabulary continuous speech recognition (LVCSR). The search algorithm, based on stack decoding, uses posterior phone probability estimates to substantially increase its efficiency with minimal effect on accuracy. In particular, the search space is dramatically reduced by phone deactivation pruning where phones with a small local posteriorprobability are deactivated. This approach

In this article I introduce the idea of conditional independence of separated subtrees as a principle by which to estimate the posteriorprobability 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 posteriorprobability 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; posteriorprobabilities of trees.

Tao, et al have recently proposed the posteriorprobability support vector machine (PPSVM) which uses soft labels derived from estimated posteriorprobabilities to be more robust to noise and outliers. Tao, et al's model uses a window-based density estimator to calculate the posteriorprobabilities and is a binary classifier. We propose a neighbor-based density estimator and also extend the model to the multiclass case. Our bias-variance analysis shows that the decrease in error by PPSVM is due to a decrease in bias. On 20 benchmark data sets, we observe that PPSVM obtains accuracy results that are higher or comparable to those of canonical SVM using significantly fewer support vectors. PMID:18269944

Objective The use of haplotypes to impute the genotypes of unmeasured single nucleotide variants continues to rise in popularity. Simulation results suggest that the use of the dosage as a one-dimensional summary statistic of imputation posteriorprobabilities may be optimal both in terms of statistical power and computational efficiency, however little theoretical understanding is available to explain and unify these simulation results. In our analysis, we provide a theoretical foundation for the use of the dosage as a one-dimensional summary statistic of genotype posteriorprobabilities from any technology. Methods We analytically evaluate the dosage, mode and the more general set of all one-dimensional summary statistics of two-dimensional (three posteriorprobabilities that must sum to 1) genotype posteriorprobability vectors. Results We prove that the dosage is an optimal one-dimensional summary statistic under a typical linear disease model and is robust to violations of this model. Simulation results confirm our theoretical findings. Conclusions Our analysis provides a strong theoretical basis for the use of the dosage as a one-dimensional summary statistic of genotype posteriorprobability vectors in related tests of genetic association across a wide variety of genetic disease models.

This paper proposes a novel object tracking method that is robust to a cluttered background and a large motion. First, a posteriorprobability measure (PPM) is adopted to locate the object region. Then the momentum based level set is used to evolve the object contour in order to improve the tracking precision. To achieve rough object localization, the initial target

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

Motivation: A limitation of current methods used to declare significance in genome-wide association studies (GWAS) is that they do not provide clear information about the probability that GWAS findings are true of false. This lack of information increases the chance of false discoveries and may result in real effects being missed. Results: We propose a method to estimate the posteriorprobability that a marker has (no) effect given its test statistic value, also called the local false discovery rate (FDR), in the GWAS. A critical step involves the estimation the parameters of the distribution of the true alternative tests. For this, we derived and implemented the real maximum likelihood function, which turned out to provide us with significantly more accurate estimates than the widely used mixture model likelihood. Actual GWAS data are used to illustrate properties of the posteriorprobability estimates empirically. In addition to evaluating individual markers, a variety of applications are conceivable. For instance, posteriorprobability estimates can be used to control the FDR more precisely than Benjamini–Hochberg procedure. Availability: The codes are freely downloadable from the web site http://www.people.vcu.edu/?jbukszar. Contact: jbukszar@vcu.edu Supplementary information: Supplementary data are available at Bioinformatics online.

Bukszar, Jozsef; McClay, Joseph L.; van den Oord, Edwin J. C. G.

The method of Laplace is used to approximate posteriorprobabilities for a collection of polynomial regression models when the errors follow a process with a noninvertible moving average component. These results are useful in the problem of period-change analysis of variable stars and in assessing the posteriorprobability that a time series with trend has been overdifferenced. The nonstandard covariance

A nonparametric estimate for the posteriorprobabilities in the classification problem using multivariate smoothing splines is proposed. This estimate presents a nonparametric alternative to logistic discrimination and to survival curve estimation. It is ...

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

This paper puts forward a Bayesian method for multiple gross errors location and estimation, and studies the masking and swamping problem in multiple gross errors detection from a new point of view, further proposes the corresponding feasible solution. First, the Bayesian method for gross error location is established based on the posteriorprobabilities of classification variables, each of which is used to determine whether each observation contains gross error or not. When some interactions exist among observations with multiple gross errors, the above-mentioned method may lead to the failure of detection due to masking and swamping. For that, on the basis of analyzing the character of masking and swamping, starting from the eigen structure of the sample correlation coefficient matrix of the classification vector, we give the Bayesian unmasking method to locate multiple gross errors, and design the corresponding algorithm, namely the adaptive Gibbs sampling algorithm. Finally, applying the mean shift model, we raise a Bayesian approach to estimate gross errors. Significant applications of the approach show the promising results on overcoming masking and swamping.

Probability Guess the Probability Do you know the probability? Take an educated guess. Probability - Guess the next card What's the next card? Is it higher or lower? Probability knowledge will help. Fish Tank Probability Fish Tank Probability. Do you know what you'll catch next? Ball Probability Predict the probability red and blue balls will be chosen. ...

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 ...

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. ...

In a companion paper (13), we proved that two specific constructions of multihypothesis sequential tests, which we refer to as Multihypothesis Sequential Probability Ratio Tests (MSPRT's), are asymptotically optimal as the decision risks (or error probabilities) go to zero. The MSPRT's asymptotically minimize not only the expected sample size but also any positive moment of the stopping time distribution, under

Vladimir P. Dragalin; Alexander G. Tartakovsky; Venugopal V. Veeravalli

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

For pt. I see ibid. vol.45, p.2448-61, 1999. We proved in pt.I that two specific constructions of multihypothesis sequential tests, which we refer to as multihypothesis sequential probability ratio tests (MSPRTs), are asymptotically optimal as the decision risks (or error probabilities) go to zero. The MSPRTs asymptotically minimize not only the expected sample size but also any positive moment of

Vladimir P. Dragalin; Alexander G. Tartakovsky; Venugopal V. Veeravalli

This series of videos, created by Salman Khan of the Khan Academics, introduces students to basic probability. Anyone using these videos should a reasonable grounding in basic algebra before viewing. This collection features seventeen different videos covering a broad array of topics within the discipline. Overall, this should serve as a solid introduction to this field.

Lack of an accurate generative model makes it hard to use classical MAP segmentation algorithms to jointly segment the epi- and the endocardium in ultrasound rodent cardiac images. This paper proposes an alternate methodology for such segmentation. The methodology directly models the posteriorprobability of segmentation using penalized logistic models. A level-set segmentation algorithm is developed using direct posterior models.

Posterior knee pain is a common patient complaint. There are broad differential diagnoses of posterior knee pain ranging from common causes such as injury to the musculotendinous structures to less common causes such as osteochondroma. A precise understanding of knee anatomy, the physical examination, and of the differential diagnosis is needed to accurately evaluate and treat posterior knee pain. This article provides a review of the anatomy and important aspects of the history and physical examination when evaluating posterior knee pain. It concludes by discussing the causes and management of posterior knee pain.

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

This paper proposes the use of approximate posterior distributions resulting from operational prior distributions chosen with regard to the realized likelihood function. L.J. Savage's “precise measurement” is generalized for approximation in terms of an arbitrary operational prior density, including mixed-type prior distributions with positive probabilities on singular subsets. A new approximation is also given relating such distributions to absolutely continuous

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.

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)

The Markov Chain Monte Carlo (MCMC) technique provides a means to generate a random sequence of model realizations that sample the posteriorprobability 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.

The Probability Hypothesis Density (PHD) filter propagates the first-moment approximation to the multi-target Bayesian posterior distribution while the Cardinalized PHD (CPHD) filter propagates both the posterior likelihood of (an unlabeled) target state and the posteriorprobability mass function of the number of targets. Extensions of the PHD filter to the multiple model (MM) framework have been published and were implemented

The determination of subjective probability as degree of felt certainty is considered. A detailed analysis is given of the problem of changes in feelings of uncertainty, defined as revisions of opinion. It appears that people seem to program their behavio...

We use the Dirichlet distribution in a new application as a tractable model for the variability between personal prior probability vectors over a large population of persons. Given a common realized likelihood function, the resulting population distribution of coherent personal posteriorprobability vectors is analyzed and found to have mixed moments expressible as a one-dimensional integral. Implications for the study

The relationship between Popper spaces (conditional probability spaces that satisfy some regularity conditions), lexicographic probability systems (LPS's) (Blume, Brandenburger, and Dekel 1991a; Blume, Brandenburger, and Dekel 1991b), and nonstandard prob...

This resource shows the relation between quantum wave functions and probabilities. The user can draw a 1D wavefunction, and observe the resultant probability distribution. Both the probability density at a single point and the probability in any interval can be measured.

Two cases of posterior form sympathetic ophthalmia are presented. The histologic abnormalities in one of them are described. Based on findings in these two cases and other descriptions of posterior form sympathetic ophthalmia in the literature, the authors conclude that except for absence of anterior uveal tract involvement, there is no histopathologic difference between posterior form sympathetic ophthalmia and classical sympathetic ophthalmia. Although there is disagreement in the literature, the authors also conclude that the therapy and prognosis of posterior form sympathetic ophthalmia does not differ from that of classical sympathetic ophthalmia. Images FIGURE 1 FIGURE 2 FIGURE 3 A FIGURE 3 B FIGURE 4 A FIGURE 4 B

Because of their tendency to progressively enlarge with compression of adjacent structures, as well as the small chance of malignancy, most intrathoracic goiters should be excised surgically. Most anterior substernal goiters and some ipsilateral posterior mediastinal goiters can be removed safely through a cervical incision. Large posterior mediastinal goiters, contralateral retrotracheal or retroesophageal posterior mediastinal goiters, and isolated mediastinal goiters with no significant cervical connection are best removed through a combined cervical and thoracic approach. The Lahey Clinic experience with three patients with posterior mediastinal goiter is described. PMID:3409742

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

Spinal osteotomies are used to treat partially flexible and fixed deformities. Fixed thoracic spinal deformities have been traditionally treated with anterior release and posterior correction with fusion. In recent decades, it has been shown that posterior-only osteotomies might be sufficient to achieve proper deformity correction with lower complication rates than with combined anterior and posterior procedures. Different types of osteotomies have been described to treat spinal deformities through a single posterior approach. These include posterior column osteotomies such as the Smith-Petersen osteotomy and the Ponte osteotomy, and three-column osteotomies such as the pedicle subtraction osteotomy, the posterior vertebral column resection and the posterior vertebral column decancellation. In general, three-column osteotomies are most commonly performed in the lumbar spine, where the vast majority of reports have focused on. They can also be performed in the thoracic spine in the setting of rigid thoracic deformity. A progressive increase in complications has been reported with more aggressive osteotomies. The aim of this article was to describe the most common posterior spinal osteotomies used to treat adult thoracic spinal deformities, with special emphasis on the technical aspects, complications and outcomes, based on current publications and European Spine Study Group (ESSG) data. PMID:24781506

SUMMARY The increasing demand of esthetics and the progressive advances in restorative dentistry leads the utilization of restoration of the posterior teeth by esthetic restorative materials. The major problem that the clinicians face when restoring posterior teeth by resin composites is the polimerization contraction and the subsequent formation of microleakage. The studies of reducing these polimerization contraction involves both the

Most mediastinal goiters are retrosternally situated in the anterior mediastinal compartment. Posterior mediastinal goiters, either retrotracheal or retroesophageal, are rare. We herein describe a case involving a retrotracheal goiter in the right posterior mediastinum, which was excised using a combined cervico-partial sternotomy and right thoracotomy approach. PMID:15353470

Chong, Chee-Fui; Cheah, Wei-Keat; Sin, Fai-Lam; Wong, Poo-Sing

Several past calculations of collision probabilities between pairs of bodies on independent orbits have yielded inconsistent results. We review the methodologies and identify their various problems. Greenberg's (1982) collision probability formalism (now with a corrected symmetry assumption) is equivalent to Wetherill's (1967) approach, except that it includes a way to avoid singularities near apsides. That method shows that the procedure by Namiki and Binzel (1991) was accurate for those cases where singularities did not arise.

Nine cases of hemifacial spasm have been treated by posterior fossa exploration without mortality or significant morbidity. In only three was definite pathology found, but the hemifacial spasm was abolished in eight patients and markedly diminished in the remaining patient. The condition has reccurred in one patient. Microsurgical techniques make the operation safe and accurate. We suggest that this procedure

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.

A 7-year-old boy with Goldenhar syndrome was diagnosed to have a posterior cranial fossa dermoid cyst. The presence of such a combination of clinical entities has not been reported earlier. The embryonic dysgenesis causing midline posterior fossa dermoid and other anomalies observed in Goldenhar syndrome occur between the third and fifth week of intrauterine life and are probably interrelated. This

The probability hypothesis density (PHD) recursion propagates the posterior intensity of the random finite set of targets in time. The cardinalized PHD (CPHD) recursion is a generalization of the PHD recursion, which jointly propagates the posterior intensity and the posterior cardinality distribution. In general, the CPHD recursion is computationally intractable. This paper proposes a closed-form solution to the CPHD recursion

Posterior urethral valves represent the most common post-vesical obstructive malformation. They affect the male gender and appear as intraluminal folds located immediately proximal to the verumontanum. One of the most credited pathogenetic theories considers them an anomalous insertion of mesonephric duct into the cloaca or an incomplete involution of plicae colliculi. At present, the diagnosis of posterior urethral valves is prenatal and the pattern is characterized by detrusor hypertrophy and more or less marked hydroureteronephrosis. Urinary tract disorders that accompany posterior urethral valves include moderate hydroureteronephrosis to severe functional impairment of the entire urinary tract with consequent renal failure. Treatment of posterior urethral valves consists in their resection. At present, with miniaturized endoscopes, valve fulguration is feasible also in newborn infants. In low-weight patients or in case of poor general condition, temporary external urinary bypass (e.g. cystostomy) is feasible. PMID:12696266

A technique for creating a posterior capsulorhexis during phacoemulsification is presented. It can be used in cases with posterior capsule tears or opacities. The free edge of the capsule is grasped with suction using a 2 mL syringe and a 27 gauge Rycroft cannula introduced via the paracentesis. The edge is then manipulated to produce a continuous curvilinear opening in the posterior capsule. The combination of a closed eye plus the use of a viscoelastic agent in the anterior chamber and capsular bag minimizes the possibility of vitreous prolapse during the maneuver. Occlusion of the cannula tip by the posterior capsule reduces the risk of vitreous aspiration. In-the-bag intraocular lens implantation is readily achieved. PMID:10476499

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)

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 posteriorprobabilities…

Renal vein compression syndromes are rare causes of hematuria and can be divided into anterior and posterior nutcracker syndrome. When the left renal vein is compressed between the aorta and the superior mesenteric artery it causes anterior nutcracker syndrome. The posterior nutcracker syndrome is very rare and is considered when the left renal vein is compressed between the aorta and vertebral column. Symptoms of nutcracker syndromes may include intermittent left flank pain associated with hematuria, proteinuria, and sometimes with symptoms of pelvic congestion. Diagnosis is often difficult and plan for treatment is always challenging and requires careful evaluation of the patient's history and workup findings. We present a rare case report of a posterior nutcracker syndrome diagnosed in a young lady with long-standing symptoms that required surgical intervention. PMID:21890560

This study examines 11 probability distributions to determine which distribution best describes demand during leadtime for 1H Cognizance Symbol (Cog) material. Proper selection of the distribution is critical in the accurate calculation of reorder levels....

Play Plinko and develop your knowledge of statistics. Drops balls through a triangular grid of pegs and see the balls random walk through the lattice. Watch the histogram of final positions build up and approach the binomial distribution. Inspired by the Virtual Lab in Probability and Statistics at U. Alabama in Huntsville (www.math.uah.edu/stat)

In decision theory, mathematical analysis shows that once the sampling distribution, loss function, and sample are specified, the only remaining basis for a choice among different admissible decisions lies in the prior probabilities. Therefore, the logical foundations of decision theory cannot be put in fully satisfactory form until the old problem of arbitrariness (sometimes called \\

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.

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.

... but is still able to help keep the knee joint stable. Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to ... the ligament. Grade 3 Sprains. This type of sprain is most commonly ... and the knee joint is unstable. Posterior cruciate ligament tears tend ...

This study evaluated the outcomes, complications, and recurrence rates of posterior cranial fossa meningiomas. We retrospectively reviewed our surgical experience with 64 posterior cranial fossa meningiomas. Mean age was 56 years with a female preponderance (67.2%). Headache was the most common symptom. Retrosigmoid approach was the commonest surgical procedure (23.4%). The incidence of cranial nerve related complications was 28%. Postoperatively facial nerve weakness was observed in 11%. The incidence of cerebrospinal fluid leak was 4.6%. Gross total resection was achieved in 37 patients (58%). Sixteen patients (25%) with residual tumors underwent Gamma knife radiosurgery. Recurrence or tumor progression was observed in 12 patients (18.7%). Operative mortality was 3.1%. At their last follow-up, 93% of the cases achieved Glasgow Outcome Scale scores 4 or 5. Total excision is the ideal goal which can be achieved with meningiomas located in certain location, such as lateral convexity, but for other posterior fossa meningiomas the close proximity of critical structures is a major obstacle in achieving this goal. In practicality, a balance between good functional outcome and extent of resection is important for posterior cranial fossa meningiomas in proximity to critical structures.

We present a method to compute the conditional distribution of a statistical shape model given partial data. The result is a "posterior shape model", which is again a statistical shape model of the same form as the original model. This allows its direct use in the variety of algorithms that include prior knowledge about the variability of a class of shapes with a statistical shape model. Posterior shape models then provide a statistically sound yet easy method to integrate partial data into these algorithms. Usually, shape models represent a complete organ, for instance in our experiments the femur bone, modeled by a multivariate normal distribution. But because in many application certain parts of the shape are known a priori, it is of great interest to model the posterior distribution of the whole shape given the known parts. These could be isolated landmark points or larger portions of the shape, like the healthy part of a pathological or damaged organ. However, because for most shape models the dimensionality of the data is much higher than the number of examples, the normal distribution is singular, and the conditional distribution not readily available. In this paper, we present two main contributions: First, we show how the posterior model can be efficiently computed as a statistical shape model in standard form and used in any shape model algorithm. We complement this paper with a freely available implementation of our algorithms. Second, we show that most common approaches put forth in the literature to overcome this are equivalent to probabilistic principal component analysis (PPCA), and Gaussian Process regression. To illustrate the use of posterior shape models, we apply them on two problems from medical image analysis: model-based image segmentation incorporating prior knowledge from landmarks, and the prediction of anatomically correct knee shapes for trochlear dysplasia patients, which constitutes a novel medical application. Our experiments confirm that the use of conditional shape models for image segmentation improves the overall segmentation accuracy and robustness. PMID:23837968

Albrecht, Thomas; Lüthi, Marcel; Gerig, Thomas; Vetter, Thomas

Posterior Microphthalmos Pigmentary Retinopathy Syndrome (PMPRS). Posterior microphthalmos (PM) is a relatively infrequent type of microphthalmos where posterior segment is predominantly affected with normal anterior segment measurements. Herein, we report two siblings with posterior microphthalmos retinopathy syndrome with postulated autosomal recessive mode of inheritance. A 13-year-old child had PM and retinitis pigmentosa (RP) and his 7-year-old sister had PM, RP, and foveoschisis. The genetics of this syndrome and variable phenotype is discussed. Importance of being aware of posterior microphthalmos and its posterior segment associations is highlighted. PMID:21416382

Arachnoid cysts of the posterior fossa are rare lesions that are considered to be mostly congenital in origin. In this article, we retrospectively review 12 patients who underwent surgical treatment for their symptomatic posterior fossa arachnoid cysts. The most common presenting symptoms were gait disturbances and headache. The diagnosis was established on computed tomography or magnetic resonance imaging. Surgery consisted of cyst wall excision with fenestration in nine cases and shunting procedures in three cases. In all cases except one who-died, the postsurgical follow-up neuroradiological investigations showed that the cysts had decreased in size, the cerebellum had re-expanded, and if there was preoperative hydrocephalus, the ventricular size was decreased. The follow-up period ranged from 1 to 11 years. All surviving cases are free of symptoms and no arachnoid cysts recurred. The classification, pathophysiology, differential diagnosis and surgical treatment of infratentorial arachnoid cysts are discussed and the relevant literature is reviewed. PMID:10492679

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

Thirteen posterior Monteggia fracture-dislocations in adults were treated surgically at the Massachusetts General Hospital from 1980 to 1988. A characteristic lesion was observed, consisting of a proximal ulna fracture with a triangular or quandrangular fracture at or near the level of the coronoid, a posterior or posterolateral radiocapitellar dislocation, and, in 10 cases, a radial head fracture. Nine patients were women and four were men, with an average age of 56 years. Following reduction of the radiocapitellar dislocation, the ulnar fractures were treated with plates in each case. Seven fractured radial heads were excised, one replaced with a silicone prosthesis, and three treated by open reduction and internal fixation. The 11 surviving patients were observed using the performance index of Broberg and Morrey at an average follow-up time of 38.4 months. The conditions of three were rated excellent, three good, four fair, and one poor. Incomplete reduction of the ulnar fracture with residual posterior radiocapitellar subluxation was observed in four cases, all leading to loss of forearm supination. We believe this lesion to be more common than previously reported. Recognition of its specific anatomic features is essential to achieve a functional outcome. PMID:1761999

Jupiter, J B; Leibovic, S J; Ribbans, W; Wilk, R M

Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that is characterized by a progressive decline in visuospatial, visuoperceptual, literacy and praxic skills. The progressive neurodegeneration affecting parietal, occipital and occipito-temporal cortices which underlies PCA is attributable to Alzheimer's disease (AD) in the majority of patients. However, alternative underlying aetiologies including Dementia with Lewy Bodies (DLB), corticobasal degeneration (CBD) and prion disease have also been identified, and not all PCA patients have atrophy on clinical imaging. This heterogeneity has led to diagnostic and terminological inconsistencies, caused difficulty comparing studies from different centres, and limited the generalizability of clinical trials and investigations of factors driving phenotypic variability. Significant challenges remain in identifying the factors associated with both the selective vulnerability of posterior cortical regions and the young age of onset seen in PCA. Greater awareness of the syndrome and agreement over the correspondence between syndrome-and disease-level classifications are required in order to improve diagnostic accuracy, research study design and clinical management.

Crutch, Sebastian J; Lehmann, Manja; Schott, Jonathan M; Rabinovici, Gil D; Rossor, Martin N; Fox, Nick C

Accurate identification of genetic variants from next-generation sequencing (NGS) data is essential for immediate large-scale genomic endeavors such as the 1000 Genomes Project, and is crucial for further genetic analysis based on the discoveries. The key challenge in single nucleotide polymorphism (SNP) discovery is to distinguish true individual variants (occurring at a low frequency) from sequencing errors (often occurring at frequencies orders of magnitude higher). Therefore, knowledge of the error probabilities of base calls is essential. We have developed Atlas-SNP2, a computational tool that detects and accounts for systematic sequencing errors caused by context-related variables in a logistic regression model learned from training data sets. Subsequently, it estimates the posterior error probability for each substitution through a Bayesian formula that integrates prior knowledge of the overall sequencing error probability and the estimated SNP rate with the results from the logistic regression model for the given substitutions. The estimated posterior SNP probability can be used to distinguish true SNPs from sequencing errors. Validation results show that Atlas-SNP2 achieves a false-positive rate of lower than 10%, with an approximately 5% or lower false-negative rate. PMID:20019143

Shen, Yufeng; Wan, Zhengzheng; Coarfa, Cristian; Drabek, Rafal; Chen, Lei; Ostrowski, Elizabeth A; Liu, Yue; Weinstock, George M; Wheeler, David A; Gibbs, Richard A; Yu, Fuli

Accurate identification of genetic variants from next-generation sequencing (NGS) data is essential for immediate large-scale genomic endeavors such as the 1000 Genomes Project, and is crucial for further genetic analysis based on the discoveries. The key challenge in single nucleotide polymorphism (SNP) discovery is to distinguish true individual variants (occurring at a low frequency) from sequencing errors (often occurring at frequencies orders of magnitude higher). Therefore, knowledge of the error probabilities of base calls is essential. We have developed Atlas-SNP2, a computational tool that detects and accounts for systematic sequencing errors caused by context-related variables in a logistic regression model learned from training data sets. Subsequently, it estimates the posterior error probability for each substitution through a Bayesian formula that integrates prior knowledge of the overall sequencing error probability and the estimated SNP rate with the results from the logistic regression model for the given substitutions. The estimated posterior SNP probability can be used to distinguish true SNPs from sequencing errors. Validation results show that Atlas-SNP2 achieves a false-positive rate of lower than 10%, with an ?5% or lower false-negative rate.

Shen, Yufeng; Wan, Zhengzheng; Coarfa, Cristian; Drabek, Rafal; Chen, Lei; Ostrowski, Elizabeth A.; Liu, Yue; Weinstock, George M.; Wheeler, David A.; Gibbs, Richard A.; Yu, Fuli

The Probability Hypothesis Density (PHD) filter propagates the first-moment approximation to the multi-target Bayesian posterior distribution while the Cardinalized PHD (CPHD) filter propagates both the posterior likelihood of (an unlabeled) target state and the posteriorprobability mass function of the number of targets. Extensions of the PHD filter to the multiple model (MM) framework have been published and were implemented either with a Sequential Monte Carlo or a Gaussian Mixture approach. In this work, we introduce the multiple model version of the more elaborate CPHD filter. We present the derivation of the prediction and update steps of the MMCPHD particularized for the case of two target motion models and proceed to show that in the case of a single model, the new MMCPHD equations reduce to the original CPHD equations.

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

The probability hypothesis density (PHD) recursion propagates the posterior intensity of the random finite set of targets in time. The cardinalized PHD (CPHD) recursion is a generalization of the PHD recursion, which jointly propagates the posterior intensity and the posterior cardinality distribution. The incorporation of cardinality information naturally improves the accuracy and stability of state estimates. In general, the CPHD

Surgical treatment for epileptic seizures emanating from the posterior cerebral cortex (occipital, parietal, posterior temporal areas) is less common than for seizures from the anterior temporal and frontal regions. The diagnosis entails integrating the combination of clinical, electrographical, neuropsychological, and imaging studies. Extremely important is the knowledge of the pathways of possible suprasylvian spread anteriorly toward the central sulcus of

Fourteen (74%) of 19 patients obtained a significant reduction in seizures after posterior corticectomy; 6 (32%) were seizure-free over a median follow-up of 3.7 years (range, 1 to 14 years). Surgery included limited resections of the occipital lobe in 16 patients, posterior temporal region in 11, and posterior portion of parietal lobe in 7. Surgical failure related to probable multiple areas of epileptogenesis (4 patients), or limited resections (2 patients) to preserve visual fields (2 patients) and to avoid dyslexia (1 patient). Of 14 patients without a complete hemianopia preoperatively, 6 (43%) developed a new or increased visual field deficit, 2 (14%) of which were hemianopia. Four (36%) of 11 occipital lobe resections resulted in a new or increased visual field deficit: quadrantanopia in 3 and hemianopia in 1. Visual phenomena were the most common initial ictal symptoms, occurring in 13 (68%) of the 19 patients. Twelve patients had complex partial seizures: in 2, always without warning; in 7, always following an aura, usually visual; and in 3 patients, with or without warning. Scalp electroencephalography identified the origin of most recorded seizures in 12 (63%) of the 19 patients. A principal interictal spike focus appeared in 15 patients (79%), and always correlated with the epileptogenic lobe as defined by scalp and/or subdural-recorded seizures (14 patients) or by clinical analysis and computed tomography (1 patient). PMID:1892366

Colon cancer is the second leading cause of cancer-related death in the United States. Earlier detection and removal of polyps can dramatically reduce the chance of developing malignant tumor. Due to some limitations of optical colonoscopy used in clinic, many researchers have developed virtual colonoscopy as an alternative technique, in which accurate colon segmentation is crucial. However, partial volume effect and existence of residue make it very challenging. The electronic colon cleaning technique proposed by Chen et al is a very attractive method, which is also kind of hard segmentation method. As mentioned in their paper, some artifacts were produced, which might affect the accurate colon reconstruction. In our paper, instead of labeling each voxel with a unique label or tissue type, the percentage of different tissues within each voxel, which we call a mixture, was considered in establishing a maximum a posteriorprobability (MAP) image-segmentation framework. A Markov random field (MRF) model was developed to reflect the spatial information for the tissue mixtures. The spatial information based on hard segmentation was used to determine which tissue types are in the specific voxel. Parameters of each tissue class were estimated by the expectation-maximization (EM) algorithm during the MAP tissue-mixture segmentation. Real CT experimental results demonstrated that the partial volume effects between four tissue types have been precisely detected. Meanwhile, the residue has been electronically removed and very smooth and clean interface along the colon wall has been obtained.

Li, Xiang; Liang, Zhengrong; Zhang, PengPeng; Kutcher, Gerald J.

Tibialis posterior dysfunction is a complex progressive condition caused primarily by injury to the tibialis posterior tendon, leading to acquired pes planus. The tibialis posterior is the most frequent ankle tendon to be injured, and the disorder commonly occurs in late middle-aged females. Degenerative, inflammatory, functional and post-traumatic aetiologies have all been proposed. Failure of the tibialis posterior tendon causes excessive load stress on the spring ligament and sinus tarsi ligaments. A wide spectrum of bony and soft-tissue abnormalities may be seen on plain radiographs, ultrasound and MRI, including malalignment, anatomical variants, and enthesopathic and tendinopathic changes. Knowledge of the anatomical and biomechanical considerations in tibialis posterior dysfunction allows the radiologist to diagnose injury to key structures and provide prognostic information that may assist with management options to prevent further flat foot deformity. PMID:18591197

Posterior reversible encephalopathy syndrome (PRES) is a recently proposed cliniconeuroradiologic entity with several well-known causes, such as hypertensive encephalopathy, eclampsia, and the use of cytotoxic and immunosuppressive drugs, as well as some causes more recently described. PRES is characterized by neuroimaging findings of reversible vasogenic subcortical edema without infarction. The pathogenesis is incompletely understood. Two opposing hypotheses are commonly cited, but the issue is controversial: (1) the current more popular theory suggests that severe hypertension exceeds the limits of autoregulation, leading to breakthrough brain edema; (2) the earlier original theory suggests that hypertension leads to cerebral autoregulatory vasoconstriction, ischemia, and subsequent brain edema. The clinical syndrome of PRES typically involves headache, encephalopathy, visual symptoms, and seizures. The clinical presentation is often nonspecific, and therefore the diagnosis of PRES has come to increasingly rely on magnetic resonance imaging (MRI) abnormalities consistent with PRES with documented recovery clinically and on repeated neuroimaging. The diagnosis has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure and/or discontinuing the offending drug. PMID:24365441

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

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

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

AdaBoost, a machine learning technique, is employed for supervised classification of land-cover categories of geostatistical data. We introduce contextual classifiers based on neighboring pixels. First, posteriorprobabilities are calculated at all pixels. Then, averages of the log posteriors are calculated in different neighborhoods and are then used as contextual classification functions. Weights for the classification functions can be determined by

Primary posterior mediastinal hydatid cyst is a serious health problem for the Mediterranean countries. We diagnosed a case of a 46-year-old female with a primary posterior mediastinum hydatid cyst on CT and MRI. It was provisionally identified as either a hydatid cyst or bronchogenic cyst or neuroenteric cyst. CT guided aspiration with 18 gauge needle confirmed as hydatid sand. This is very rare in this population but it should be kept in mind when one is looking at any cyst in the posterior mediastinum. PMID:24709247

Ahmed, Mughis Uddin; Eid, Ahmed Fathi; Al-Hawashim, Nadia; Sheikh, Mohammed Younus; Yiannakou, Nearchos

This article studies the construction of a Bayesian confidence interval for the ratio of marginal probabilities in matched-pair designs. Under a Dirichlet prior distribution, the exact posterior distribution of the ratio is derived. The tail confidence interval and the highest posterior density (HPD) interval are studied, and their frequentist performances are investigated by simulation in terms of mean coverage probability

An ectopic posterior pituitary gland is a rare condition and may present with an empty pituitary fossa, hypoplasia or absence of the infundibular stalk and resultant short stature due to growth hormone deficiency. The location of the ectopic lobe can vary, but it is most commonly situated along the median eminence in the floor of the third ventricle. We report a case of an ectopic posterior pituitary gland, describe the causes and discuss the diagnostic imaging features. PMID:24209704

The posterior femoral cutaneous nerve is a sensory nerve comprised of fibers originating from the anterior and posterior divisions of the first three sacral segments. It exists the pelvis distal to the piriformis muscle and proceeds distally, superficial to and between the medial and lateral hamstring musculature. The nerve's major cutaneous distribution is the posterior aspect of the thigh and a variable area of the posterior calf. An electrophysiologic technique to assess the peripheral axons of the posterior femoral cutaneous nerve is described. A recording electrode is placed 6cm proximal to the midpopliteal fossa and the nerve is stimulated supramaximally 12cm proximally on a line between the active electrode and the ischial tuberosity. A ground electrode is placed just proximal to the active recording electrode. The lower extremities of 40 individuals with a mean age of 34 years (20 to 78 years) were examined. The mean peak latency of the response is 2.8 (2.3 to 3.4) msec +/- 0.2msec with a mean amplitude of 6.5 (4.1 to 12.0) microV +/- 1.5 microV. This technique may facilitate the proximal evaluation of lower extremity peripheral neuropathies, lesions of the posterior femoral cutaneous nerve, or the assessment of the peripheral nervous system in persons with lower extremity amputations. PMID:2241545

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. The probability mapping approach illustrated in this paper appears to offer site operators a reasonable, quantitative methodology for many environmental remediation decisions and allows evaluation of the risk associated with those decisions. For example, output from this approach can be used in quantitative, cost-based decision models for evaluating possible site characterization and/or remediation plans, resulting in selection of the risk-adjusted, least-cost alternative. The methodology is completely general, and the techniques are applicable to a wide variety of environmental restoration projects. The probability-mapping approach is illustrated by application to a contaminated site at the former DOE Feed Materials Production Center near Fernald, Ohio. Soil geochemical data, collected as part of the Uranium-in-Soils Integrated Demonstration Project, have been used to construct a number of geostatistical simulations of potential contamination for parcels approximately the size of a selective remediation unit (the 3-m width of a bulldozer blade). Each such simulation accurately reflects the actual measured sample values, and reproduces the univariate statistics and spatial character of the extant data. Post-processing of a large number of these equally likely statistically similar images produces maps directly showing the probability of exceeding specified levels of contamination (potential clean-up or personnel-hazard thresholds).

Rautman, C.A.; Kaplan, P.G. [Sandia National Labs., Albuquerque, NM (United States); McGraw, M.A. [Univ. of California, Berkeley, CA (United States); Istok, J.D. [Oregon State Univ., Corvallis, OR (United States); Sigda, J.M. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

Summary form only given. Accurate transition probabilities are of fundamental importance for plasma diagnostics. However the knowledge of atomic data is still unsatisfactory for many elements. Especially for Mn II experimental f-values, determined from arc and spark discharges, show big discrepancies with calculations. Therefore we started a new project for an independent measurement of transition probabilities. Fourier Transform spectroscopy has

Posterior crossbite is defined as an inadequate transversal relationship of maxillary and mandibular teeth. Even when eliminating the etiologic factors, this malocclusion does not have a spontaneous correction, and should be treated with maxillary expansion as early as possible. This treatment aims at providing a better tooth/skeletal relationship, thereby improving masticatory function, and establishing a symmetrical condyle/fossa relationship. Should posterior crossbite not be treated early, it may result in skeletal changes, demanding a more complex approach. Additionally, an overcorrection expansion protocol should be applied in order to improve the treatment stability. Although the literature has reported a high rate of relapse after maxillary expansion, the goal of this study was to demonstrate excellent stability of the posterior crossbite correction 21 years post treatment.

de ALMEIDA, Renato Rodrigues; de ALMEIDA, Marcio Rodrigues; OLTRAMARI-NAVARRO, Paula Vanessa Pedron; CONTI, Ana Claudia de Castro Ferreira; NAVARRO, Ricardo de Lima; MARQUES, Henry Victor Alves

The patient was a 19-year-old male cadet at a military academy who was evaluated by a physical therapist in a direct-access capacity for a chief complaint of right knee pain and giving way after falling onto his right knee while snow sledding at a high rate of speed 2 weeks earlier. Knee radiographs were ordered by the physical therapist, which demonstrated a large suprapatellar joint effusion. Due to concern for a posterior cruciate ligament injury and to assess for concomitant injury, magnetic resonance imaging was ordered, which revealed disruption of the posterior cruciate ligament without injury to surrounding tissues. PMID:24256175

Glenesk, Kathleen; Fogarty, Brian T; Westrick, Richard B

Accurate reduction of ankle syndesmosis following injury is essential to minimize tibiofibular diastasis and optimize patient outcomes. Although several radiographic parameters have been described in the coronal plane to assist in reduction, tibiofibular diastasis following syndesmotic injury often occurs in the sagittal plane, with the fibula displacing posterior relative to the tibia. A technique using lateral fluoroscopic assessment of the uninjured contralateral ankle as a comparison and guide for accurate syndesmotic reduction is described. PMID:23672891

Schreiber, Joseph J; McLawhorn, Alexander S; Dy, Christopher J; Goldwyn, Elan M

Posterior ceramic bonded partial restorations are conservative and esthetic approaches for compromised teeth. Overlays constitute a less invasive alternative for tooth tissues than crown preparations. With inlays and onlays they are also indicated in case of full arch or quadrant rehabilitations including several teeth. This article screens indications and realization of this type of restorations. PMID:17432532

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

The official consumer website of: Visit ACFAS.org | About ACFAS | Información en Español ... tendon serves as one of the major supporting structures of the foot, helping it to function while walking. Posterior tibial tendon dysfunction (PTTD) is a condition caused ...

We present the magnetic resonance imaging findings of posterior ischemic optic neuropathy in a patient with posterior reversible encephalopathy syndrome secondary to hypertensive emergency. PMID:24647142

This lesson is based on several interesting problems. Each problem has a somewhat unexpected answer; in fact, many people have a hard time accepting experimental results for these problems, as the results may seem counterintuitive. This very difference in expectations and actual results leads to a deeper consideration of the related mathematics and to acquiring new tools for solving problems, namely the ideas and formulas connected with conditional probability and probability of simultaneous events.

Right ventricular (RV) or posterior infarction associated with inferior wall left ventricular acute myocardial infarction (AMI) has important therapeutic and prognostic implications. However, RV and posterior chest leads in addition to the 12-lead electrocardiogram are required for accurate detection. Body surface mapping (BSM) has greater spatial sampling and may further improve inferior wall AMI classification. Consecutive patients with chest pain

Ian B. A Menown; James Allen; John McC Anderson; A. A. Jennifer Adgey

A few remarks are first made on invariant probability measures of a transition probability operator. The notion of irreducibility is introduced for a transition operator acting on the continuous functions on a compact space and implications of this assump...

The Biodegradation Probability Program (BIODEG) calculates the probability that a chemical under aerobic conditions with mixed cultures of microorganisms will biodegrade rapidly or slowly. It uses fragment constants developed using multiple linear and non-linear regressions and d...

The mathematical entropy - unlike physical entropy - is simply a measure of uniformity for probability distributions in general. So understood, conditional entropies have the same logical structure as conditional probabilities. If, as is sometimes suppose...

We concentrate on two aspects of the article by Pothos & Busemeyer (P&B): the relationship between classical and quantum probability and quantum probability as a basis for rational decisions. We argue that the mathematical relationship between classical and quantum probability is not quite what the authors claim. Furthermore, it might be premature to regard quantum probability as the best practical rational scheme for decision making. PMID:23673037

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

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.

The literature is divided as to the necessity of an intact posterior cruciate ligament for functional stability. Pre sented here is a prospective study of isolated posterior cruciate injuries seen in the acute stage in 13 patients, 6 males and 7 females. The diagnosis of posterior cruciate ligament tear was made clinically and con firmed by arthroscopy. The average age

Dermoid cysts are uncommon tumors, and posterior fossa dermoid cysts may rarely cause abscess formation or formation of daughter abscesses within the cerebellum. At present, there are only 16 cases with posterior fossa dermoid cysts causing cerebellar abscesses reported in the literature. Two cases, 22 and 14 months old, with posterior fossa dermoid cysts and dermal sinus causing multiple cerebellar

Feyza Karagöz Güzey; N. Serdar Bas; Altay Sencer; Erhan Emel; M. Kemal Hamamcioglu; Nezih Özkan; Kemal Hepgul; Abdurrahman Aycan

this articleduring a stay at the \\\\Mathematisches Forschungsinstitut Oberwolfach", nanced also fromthe European Human Capital and Mobility Program on Quantum Probability.nite coin tosses in the third section. Suprisingly, they lead quite quickly torecent developments. In an appendix we indicate the steps which lead to the fullmathematical model of quantum probability.1. Why Classical Probability does not Suffice

This book examines how probability distributions can be used as a knowledge representation technique. It presents a mechanism that can be used to guide a selective search algorithm to solve a variety of tactical chess problems. Topics covered include probabilities and searching the B algorithm and chess probabilities - in practice, examples, results, and future work.

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

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

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…

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 posteriorprobabilities 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.

We describe a retroauricular approach, adjacent to the mastoid tip, in two patients that allowed successful biopsy of posterior skull base lesions. Diagnoses were central giant cell granuloma, an unusual tumor rarely reported in the skull base, and meningioma. In both patients, the needle biopsy accurately identified the pathology found at surgery. The described approach may allow biopsy of posterior lesions that are inaccessible with other methods. ImagesFigure 1p162-bp163-aFigure 2Figure 3Figure 4

Trans-cervical resection of posterior mediastinal goiters is usually very difficult, requiring a high thoracotomy. Until recently, using conventional video-assisted thoracoscopic surgery to resect such tumors has been technically difficult and unsafe. By virtue of 3 dimensional visualization, greater dexterity, and more accurate dissection, the Da Vinci robot, for the first time, enables a completely minimally invasive approach to the posterior superior mediastinum.

The major contribution of this paper is the computation of an accurate approximation of the symbol error probability of multidimensional signal constellations used for transmission over independent Rayleigh fading channels. Here we attempt to compute the exact error probability and show how some apparently rather gross approximations still lead to an accurate result

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

The Probability Hypothesis Density (PHD) filter is a computationally tractable alternative to the optimal nonlinear filter. The PHD filter propagates the first moment instead of the full posterior density. Evaluation of the PHD enables one to extract the number of targets as well as their individual states from noisy data with data association uncertainties. Recently, a smoothing algorithm was proposed by the authors to improve the capability of PHD based tracking. Smoothing produces delayed estimates, which yield better estimates not only for the target states but also for the unknown number of targets. However, in the case of the maneuvering target tracking problem, this single model method may not provide accurate estimates. In this paper, a multiple model PHD smoothing method is proposed to improve the tracking of multiple maneuvering targets. A fast sequential Monte Carlo implementation for a special case is also provided. Simulations are performed with the proposed method consisting of multiple maneuvering targets. Simulation results confirm the improved performance of the proposed algorithm.

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.

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

This work describes several approaches to the estimation of target detection and identification probabilities as a function of target range. A Bayesian approach to estimation is adopted, whereby the posteriorprobability distributions associated with these probabilities are analytically derived. The parameter posteriors are then used to develop credible intervals quantifying the degree of uncertainty in the parameter estimates. In our first approach we simply show how these credible intervals evolve as a function of range. A second approach, also following the Bayesian philosophy, attempts to directly estimate the parameterized performance curves. This second approach makes efficient use of the available data and yields a distribution of probability versus range curves. Finally, we demonstrate both approaches using experimental data collected from wide field-of-view imagers focused on maritime targets. PMID:23669659

Nichols, Jonathan M; Judd, Kyle P; Olson, Colin C; Waterman, James R; Nichols, James D

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

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.

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

The authors present a case of calcified posterior cruciate ligament (PCL). A 61-year-old female presented in our department reporting 12 months history of knee pain that was getting worse during the night. The patient was under medication for epileptic seizure, osteoporosis and hyperthyroidism. X-rays demonstrated calcification of the PCL. CT and MRI excluded any other intra-articular and extra-articular pathology. Arthroscopic debridement of the calcium deposits was performed and the symptoms resolved immediately, while the postoperative x-rays were normal. Histological examination confirmed the calcium nature of the lesion. Two years postoperatively the patient remains asymptomatic.

The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target filter based on random finite sets. It propagates the PHD function, the first order moment of the posterior multi-target density, from which the number of targets as well as their individual states can be extracted. Furthermore, the sequential Monte Carlo (SMC) approximation of the PHD

The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target filter based on finite set statistics. It propagates the PHD function, a first order moment of the full multi-target posterior density. The peaks of the PHD function give estimates of the target states. However, the PHD filter keeps no record of target identities and hence

A new multi-target tracking algorithm, termed as the Gaussian sum convolution probability hypothesis density (GSCPHD) filter, is proposed. The filter is calculated by a bank of convolution filters with Gaussian approximations to the predicted and posterior densities. It is shown that the ability to deal with complex observation model, non or small observation noise of the GSCPHD over the Gaussian

The Probability Hypothesis Density (PHD) filter is a computationally tractable alternative to the optimal nonlinear filter. The PHD filter propagates the first moment instead of the full posterior density. Evaluation of the PHD enables one to extract the number of targets as well as their individual states from noisy data with data association uncertainties. Recently, a smoothing algorithm was proposed

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

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

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.

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

A patient had a corneal transplant with removal of an anterior chamber lens. As part of the procedure, an exchange posterior chamber lens was inserted and sutured transsclerally into the ciliary sulcus with two subconjunctival 10-0 polypropylene (Prolene) sutures. One month later the patient experienced a sudden decrease in vision and severe eye pain. Streptococcus viridans was cultured from the vitreous tap and the eye eventually was lost from this endophthalmitis. The infecting organism appeared to gain access to the eye through one of the Prolene sutures that had eroded through the conjunctiva and become exteriorized. This report presents a case in which an eroding 10-0 Prolene suture used for transscleral posterior chamber lens fixation was the probable mechanism causing endophthalmitis. This complication represents an avoidable risk unique to this type of intraocular lens fixation. PMID:2258814

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

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

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.

The concept of rank selection probabilities for stack filters has previously been introduced. If the probabilities are known, then the output distribution for i.i.d. input follows easily. There is another expression for the output distribution of a stack filter using certain quantities called Ai. The authors utilize the different forms of output distribution to derive a simple connection between the

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

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

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

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

Young adults were shown hypothetical stimulus vignettes describing mental patients and were asked to judge (a) the probability that the patient would harm someone else, (b) whether or not the patient should be categorized as “dangerous,” and (c) whether coercion should be used to ensure treatment. Probability and dangerousness judgments were systematically related and were predictive of the judged necessity

This teacher's guide to probability and statistics contains three major sections. The first section on elementary combinatorial principles includes activities, student problems, and suggested teaching procedures for the multiplication principle, permutations, and combinations. Section two develops an intuitive approach to probability through…

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

In this math lesson, learners identify the likelihood of an event by using a walk-on probability scale. Learners are encouraged to evaluate the chance of given events occurring and assigning the event a position on the probability scale. The activity immerses learners in experiences that promote discourse about probabilistic notions.

\\u000a This paper describes ANN based posterior estimates and their application to speech recognition. We replaced the standard back-propagation\\u000a with the L-BFGS quasi-Newton method. We have focused only on posterior based feature vector extraction. Our goal was a feature\\u000a vector dimension reduction. Thus we designed three posterior transforms to space with dimensionality 1 or 2. The designed\\u000a transforms were tested on

The paper discusses current methods for accurate measurements of time by conventional atomic clocks, with particular attention given to the principles of operation of atomic-beam frequency standards, atomic hydrogen masers, and atomic fountain and to the potential use of strings of trapped mercury ions as a time device more stable than conventional atomic clocks. The areas of application of the ultraprecise and ultrastable time-measuring devices that tax the capacity of modern atomic clocks include radio astronomy and tests of relativity. The paper also discusses practical applications of ultraprecise clocks, such as navigation of space vehicles and pinpointing the exact position of ships and other objects on earth using the GPS.

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.

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.

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

This applet can be used to observe how probability of outcomes for a multistage event determines the final result. The applet simulates the launch of a three-stage rocket that requires all three stages to pass tests before takeoff. The student can vary the probability of passing at each stage from 0 to 100 percent. The applet reports the overall success rate as a percent and the cumulative number of successful and failed launches. Copyright 2005 Eisenhower National Clearinghouse

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.

BACKGROUNDIf the cervical lordotic curvature has been well preserved, spondylostenosis or ossification of the posterior longitudinal ligament, with or without instability, may be approached posteriorly in selected older patients (over 65 years of age). Posterior surgical alternatives include the laminectomy with or without fusion, or laminoplasty. However, in younger patients or in geriatric patients with predominantly anterior disease with kyphosis,

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

A new Bayesian-style retrieval algorithm is demonstrated for the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). Unlike all other known passive microwave algorithms, this algorithm is able to provide not only mean (expected) rain rates for each scene but also a detailed posteriorprobability distribution of rain rates, including the fractional likelihood of non-zero rain rate as well as that of rain rate exceeding a wide range of thresholds. This is made possible by way of dimensional reduction technique that greatly increases the effective sample density of the training data base relative to a conventional method utilizing the TMI's original nine channels. The availability of posterior distributions allows uncertainty in the instantaneous retrievals to be described in far greater detail than conventional "error bars." It also allows for a more nuanced analysis of "extreme" rain events. It must be noted, however, that the posterior distributions described above are with respect to the "truth" data in the training data base (in this case, retrievals from the TRMM Precipitation Radar) and do not account for unknown errors in the instantaneous PR retrievals themselves.

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 posteriorprobability 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.

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

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.

OBJECTIVE The purpose of this study was to determine the effect of posterior repair (PR) on sexual function in patients who have undergone incontinence and/or pelvic reconstructive surgery. STUDY DESIGN A cohort study of women who underwent incontinence and/or prolapse surgery was performed. Participants completed the pelvic organ prolapse urinary incontinence sexual questionnaire (PISQ) before and after the operation. PISQ scores were compared between women who underwent PR and women who did not. RESULTS Of 73 study participants, 30 women underwent PR; 43 women did not (no PR). Although there was no difference in dyspareunia between groups pre-op, dyspareunia prevalence post-op was significantly lower in the no PR group. Preoperative PISQ scores were similar between groups. After the operation, both groups significantly improved their PISQ scores, without a difference between groups. CONCLUSION Although the incidence of dyspareunia differed between PR and no PR groups, overall improvement in sexual function was reflected in improved total PISQ scores that occurred irrespective of PR performance.

Komesu, Yuko M.; Rogers, Rebecca G.; Kammerer-Doak, Dorothy N.; Barber, Matthew D.; Olsen, Ambre L.

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.

Free probability theory provides a probabilistic framework for quantities with the highest degree of noncommutativity. This brings out the ties among von Neumann algebras of free groups, the large N limit of random multimatrix models, the operators of the Boltzmann Fock space and combinatorics of noncrossing partitions. Many concepts of classical probability theory have free probability counterparts. In particular, the free analogues of entropy and of Fisher's information will be one of the main focuses of the talk. The analysis of the free variables involved, relies on free difference quotient derivations, which give rise to bialgebras in the class with derivation comultiplication, which appears to be selfdual. Duality for such bialgebras underlies the free entropy and analytic aspects of the free Markov property.

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

This paper investigates procedures for univariate nonparametric estimation of tail probabilities. Extrapolated values for tail probabilities beyond the data are also obtained based on the shape of the density in the tail. Several estimators which use exponential weighting are described. These are compared in a Monte Carlo study to nonweighted estimators, to the empirical cdf, to an integrated kernel, to a Fourier series estimate, to a penalized likelihood estimate and a maximum likelihood estimate. Selected weighted estimators are shown to compare favorably to many of these standard estimators for the sampling distributions investigated.

Nine athletes (seven football offensive linemen, one defensive lineman, and one lacrosse player) were found at arthroscopy to have posterior labral detachment from the glenoid. In our series, this lesion is specific to contact athletes who engage their opponents with arms in front of the body. All patients had pain with bench pressing and while participating in their sport, diminishing their ability to play effectively. Conservative measures were ineffective in relieving their symptoms. Examination under anesthesia revealed symmetric glenohumeral translation bilaterally, without evidence of posterior instability. Treatment consisted of glenoid rim abradement and posterior labral repair with a bioabsorbable tack. All patients returned to complete at least one full season of contact sports and weightlifting without pain (minimum follow-up, > or = 2 years). Although many injuries leading to subluxation of the glenohumeral joint occur when an unanticipated force is applied, contact athletes ready their shoulder muscles in anticipation of impact with opponents. This leads to a compressive force at the glenohumeral joint. We hypothesize that, in combination with a posteriorly directed force at impact, the resultant vector is a shearing force to the posterior labrum and articular surface. Repeated exposure leads to posterior labral detachment without capsular injury. Posterior labral reattachment provides consistently good results, allowing the athlete to return to competition. PMID:9850774

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. The probability mapping approach illustrated in this paper appears to offer site operators a reasonable, quantitative methodology for

C. A. Rautman; P. G. Kaplan; M. A. McGraw; J. D. Istok; J. M. Sigda

A rate distortion problem is solved that is motivated by a quantum data compression problem. The goal is to send information about a source string x so that a receiver can construct a second string y for which the joint empirical probability distribution of x and y is close to some desired distribution. The problem differs from the usual rate

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

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.

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.

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.

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

Generalizing Boolean matrix decomposition to a larger class of matrix decomposition models is demonstrated, and probability matrix decomposition (PMD) models are introduced as a probabilistic version of the larger class. An algorithm is presented for the computation of maximum likelihood and maximum a posteriori estimates of the parameters of PMD…

Likelihoods and posteriors of instrumental variable (IV) regression models with strong endogeneity and\\/or weak instruments may exhibit rather non-elliptical contours in the parameter space. This may seriously affect inference based on Bayesian credible sets. When approximating posteriorprobabilities and marginal densities using Monte Carlo integration methods like importance sampling or Markov chain Monte Carlo procedures the speed of the algorithm

Lennart F. Hoogerheide; Johan F. Kaashoek; Herman K. van Dijk

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

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

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

Meningioma's account for around 15% of all primary brain tumors with some 10% of meningiomas arising in the posterior fossa. In rare cases, a meningioma can form around the endolymphatic sac. When formed in the posterior fossa, meningioma tumors can produce vague, non-specific vertiginous symptoms. Research has observed that a subset of these lesions could produce symptoms indistinguishable from those of Meniere's disease. Therefore, we described the clinical features of a case of posterior petrous meningioma with recurrent vertigo as well as the substantial resolution of symptoms after tumor removal via transmastoid approach.

Choi, Seong Jun; Lee, Jong Bin; Bae, Joon-Ho; Yoon, Jung-Hee; Lee, Ho-Jin; Kim, Chan-Ho; Park, Keehyun

Recent implementations of path sampling (PS) and stepping-stone sampling (SS) have been shown to outperform the harmonic mean estimator (HME) and a posterior simulation-based analog of Akaike’s information criterion through Markov chain Monte Carlo (AICM), in Bayesian model selection of demographic and molecular clock models. Almost simultaneously, a Bayesian model averaging approach was developed that avoids conditioning on a single model but averages over a set of relaxed clock models. This approach returns estimates of the posteriorprobability of each clock model through which one can estimate the Bayes factor in favor of the maximum a posteriori (MAP) clock model; however, this Bayes factor estimate may suffer when the posteriorprobability of the MAP model approaches 1. Here, we compare these two recent developments with the HME, stabilized/smoothed HME (sHME), and AICM, using both synthetic and empirical data. Our comparison shows reassuringly that MAP identification and its Bayes factor provide similar performance to PS and SS and that these approaches considerably outperform HME, sHME, and AICM in selecting the correct underlying clock model. We also illustrate the importance of using proper priors on a large set of empirical data sets.

Baele, Guy; Li, Wai Lok Sibon; Drummond, Alexei J.; Suchard, Marc A.; Lemey, Philippe

Recent implementations of path sampling (PS) and stepping-stone sampling (SS) have been shown to outperform the harmonic mean estimator (HME) and a posterior simulation-based analog of Akaike's information criterion through Markov chain Monte Carlo (AICM), in bayesian model selection of demographic and molecular clock models. Almost simultaneously, a bayesian model averaging approach was developed that avoids conditioning on a single model but averages over a set of relaxed clock models. This approach returns estimates of the posteriorprobability of each clock model through which one can estimate the Bayes factor in favor of the maximum a posteriori (MAP) clock model; however, this Bayes factor estimate may suffer when the posteriorprobability of the MAP model approaches 1. Here, we compare these two recent developments with the HME, stabilized/smoothed HME (sHME), and AICM, using both synthetic and empirical data. Our comparison shows reassuringly that MAP identification and its Bayes factor provide similar performance to PS and SS and that these approaches considerably outperform HME, sHME, and AICM in selecting the correct underlying clock model. We also illustrate the importance of using proper priors on a large set of empirical data sets. PMID:23090976

Baele, Guy; Li, Wai Lok Sibon; Drummond, Alexei J; Suchard, Marc A; Lemey, Philippe

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

Regardless of the approach to the cervical spine, it is clear that surgical outcome is directly related to surgical technique. Posterior decompressions must be thorough and complete because laminoforaminotomies provide an excellent means of decompressing foraminal pathology. One of the distinct advantages of posterior laminoforaminotomy is that it offers direct visualization, exposure, and decompression of the nerve root without performing a fusion. A posterior laminoforaminotomy is the preferred approach for patients with a soft lateral disk herniation, for those at increased risk for nonunion, or those for whom an anterior procedure would not be optimal. To perform a thorough decompression and prevent iatrogenic instability and neurologic deficits, however, surgeons must be familiar with the anatomy of the foramen as well as the compressive pathology. Several issues must be addressed before performing a posterior laminoforaminotomy, namely, the absence of instability and junctional kyphosis, and the proper identification of the offending pathology. PMID:17472315

We studied retrospectively the clinical features of 18 eyes of 18 patients with traumatic macular hole. The macular hole was elliptical with irregular edges in 17 eyes (94%) and its size ranged from 1/5 to 1/2 of the disc diameter. Posterior vitreous detachment was found in 3 eyes (17%); the vitreous was detached from the macula in only one of these 3 eyes. Commotio retinae, vitreous hemorrhage, hyphema, or choroidal rupture was also found in several eyes. These findings suggest that traumatic macular hole develops usually in the absence of posterior vitreous detachment and its pathogenesis is independent of the occurrence of posterior vitreous detachment. We speculate that blunt trauma-induced deformity of the eyeball or impact on the posterior pole provides a mechanical cause for the macular rupture. PMID:7484503

Yanagiya, N; Akiba, J; Takahashi, M; Kakehashi, A; Kado, M; Yoshida, A

Posterior cervical node enlargement is characteristic of clinical toxoplasmosis in adults. Lymph node biopsies from 37 patients, who were tested for toxoplasmosis by serologic and isolation studies, were examined. A characteristic pattern of sinus histiocytosis was seen in 17 of 18 posterior cervical nodes and in only 1 of 4 lymph nodes from other sites from patients with toxoplasmosis. The characteristic pattern was not seen in posterior cervical nodes or in lymph nodes from other sites from patients with other diseases. Lymphoma obscured the characteristic changes of toxoplasmosis in the posterior cervical nodes and other nodes of 5 patients with these coexisting diseases. Organisms were seen in tissue sections in only 2 instances. T gondii was isolated from mice in 14 of 17 attempts using nodes from patients with toxoplasmosis, but from none of 8 attempts using nodes from patients with other diseases. ImagesFig 3Fig 4Fig 1Fig 2

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.

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

The objective of this calculation is to calculate the probability of occurrence for fuel assembly (FA) misloads (i.e., Fa placed in the wrong location) and FA damage during FA movements. The scope of this calculation is provided by the information obtained from the Framatome ANP 2001a report. The first step in this calculation is to categorize each fuel-handling events that occurred at nuclear power plants. The different categories are based on FAs being damaged or misloaded. The next step is to determine the total number of FAs involved in the event. Using the information, a probability of occurrence will be calculated for FA misload and FA damage events. This calculation is an expansion of preliminary work performed by Framatome ANP 2001a.

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

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.

Posterior limbus vertebra (PLV) is the retropulsion of the vertebral ring apophysis resulting from disc herniation through posterior ring physis. Large PLV can cause spinal stenosis, and small PLV can be mistaken as intraspinal disc herniation. Although the clinical presentations were similar, the surgery was quite different. We had experienced preoperative misdiagnosed cases and the surgery could not be finished. Therefore we analyzed the imaging features of PLV in 34 patients in order to prompt appropriate preoperative diagnosis and surgical planning. PMID:23154012

Subdural hematomas of the posterior fossa are very rare and most cases are related to head injury. The influence of anticoagulation in cases of spontaneous development is well known. Although diagnosis is easily achieved by CT sean, atypical forms may lead to the wrong diagnosis of cerebellar hematoma. We present a case of a posterior fossa acute subdural hematoma occurring in an anticoagulated patient who was preoperatively misdiagnosed as an intracerebellar hemorrhage. PMID:14710308

Miranda, P; Alday, R; Lagares, A; Pérez, A; Lobato, R D

Context: Posterior shoulder instability is a commonly misdiagnosed disorder in many competitive athletes. Type of Study: Clinical review. Evidence Acquisition: Relevant studies on posterior shoulder instability from 1950 to 2010 in PubMed and Cochrane databases were reviewed. Results: A total of 107 studies were reviewed. Conclusion: Patients who have undergone at least 6 months of physical therapy and still experience instability symptoms should be considered for surgical stabilization directed at their underlying pathology.

Posterior reversible encephalopathy syndrome (PRES) is characterized by variable associations of seizure activity, consciousness impairment, headaches, visual abnormalities, nausea/vomiting, and focal neurological signs. The PRES may occur in diverse situations. The findings on neuroimaging in PRES are often symmetric and predominate edema in the white matter of the brain areas perfused by the posterior brain circulation, which is reversible when the underlying cause is treated. We report the case of PRES in normotensive patient with hyponatremia.

The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target filter based on finite set statistics. It propagates only the first order moment instead of the full multi-target posterior. Recently, a sequential Monte Carlo (SMC) implementation of PHD filter has been used in multi-target filtering with promising results. In this paper, we will compare the

Optimal Bayesian multi-target filtering is, in general, computationally impractical due to the high dimensionality of the multi-target state. Recently Mahler, [9], introduced a filter which propagates the first moment of the multi-target posterior distribution, which he called the Probability Hypothesis Density (PHD) filter. While this reduces the dimensionality of the problem, the PHD filter still involves intractable integrals in many

The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target Alter based on finite set statistics. It propagates the PHD function, a first-order moment of the full multi-target posterior density. The peaks of the PHD function give estimates of target states. However, the PHD filter keeps no record of target identities and hence does not

Optimal Bayesian multi-target filtering is, in general, computationally impractical owing to the high dimensionality of the multi-target state. The probability hypothesis density (PHD) filter propagates the first moment of the multi-target posterior distribution. While this reduces the dimensionality of the problem, the PHD filter still involves intractable integrals in many cases of interest. Several authors have proposed sequential Monte Carlo

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

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

In this interactive activity, learners build computer models of atoms by adding or removing electrons, protons, and neutrons. It presents the orbital model of an atom: a nucleus consisting of protons and neutrons with electrons surrounding it in regions of high probability called orbitals. Guided tasks are provided, such as constructing a lithium atom and a carbon-12 atom in the fewest possible steps. The activity concludes with a model for building a charged hydrogen atom (an ion). Within each task, students take snapshots of their work product and answer probative questions. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

Probability of causation (PC) is sometimes viewed as a great improvement by those persons who are not happy with the present rulings of courts in radiation cases. The author does not share that hope and expects that PC will not play a significant role in these issues for at least the next decade. If it is ever adopted in a legislative compensation scheme, it will be used in a way that is unlikely to please most scientists. Consequently, PC is a false hope for radiation scientists, and its best contribution may well lie in some of the spin-off effects, such as an influence on medical practice.

We analyse a system in which, due to entanglement between the spin and\\u000aspatial degrees of freedom, the reduced transmitted state has the shape of the\\u000afreely propagating pulse translated in the complex co-ordinate plane. In the\\u000acase an apparently \\

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. Geostatistical simulation provides powerful tools for investigating contaminant levels, and in particular, for identifying and using the spatial interrelationships among a set of isolated sample values. This additional information can be used to assess the likelihood of encountering contamination at unsampled locations and to evaluate the risk associated with decisions to remediate or not to remediate specific regions within a site. Past operation of the DOE Feed Materials Production Center has contaminated a site near Fernald, Ohio, with natural uranium. Soil geochemical data have been collected as part of the Uranium-in-Soils Integrated Demonstration Project. These data have been used to construct a number of stochastic images of potential contamination for parcels approximately the size of a selective remediation unit. Each such image accurately reflects the actual measured sample values, and reproduces the univariate statistics and spatial character of the extant data. Post-processing of a large number of these equally likely, statistically similar images produces maps directly showing the probability of exceeding specified levels of contamination. Evaluation of the geostatistical simulations can yield maps representing the expected magnitude of the contamination for various regions and other information that may be important in determining a suitable remediation process or in sizing equipment to accomplish the restoration.

This article and its sequel outline recent developments in the theory of infinite divisibility and Lévy processes in free probability, a subject area belonging to noncommutative (or quantum) probability. The present paper discusses the classes of infinitely divisible probability measures in classical and free probability, respectively, via a study of the Bercovici-Pata bijection between these classes. PMID:12473744

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.

We evaluated the safety and efficacy of pars plana vitrectomy (PPV) with primary posterior iris claw intraocular lens (IOL) implantation in cases of posterior dislocation of nucleus and IOL without capsular support. This was a retrospective interventional case series. Fifteen eyes underwent PPV with primary posterior iris claw IOL implantation performed by a single vitreoretinal surgeon. The main outcome measures were changes in best corrected visual acuity and anterior and posterior segment complications. A total of 15 eyes were included in this study. Eight had nucleus drop, three had IOL drop during cataract surgery and four had traumatic posterior dislocation of lens. The final postoperative best corrected visual acuity was 20/60 or better in 11 patients. This procedure is a viable option in achieving good functional visual acuity in eyes without capsular support.

Patil, Kishor B; Meleth, Padmanabhan; Prabhu, Shanker M

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.

Summary Treatment and prognosis of 14 patients of posterior fossa arterial dissections (AD) and dissecting aneurysms (DA) in one institution was reviewed. Internal trapping of aneurysm was performed for six patients presenting with SAH (three Vertebral, one posterior cerebral, one posterior inferior cerebellar, one anterior inferior cerebellar DA). The patency of the parent arteries was preserved in four DA patients with SAH (two Vertebral, two Basilar DA), 1 incidental vertebral DA, and one DA patient with brainstem infarction using stents and coils (four patients) or coils only (two patient). Proximal occlusion of parent artery was performed in a vertebral DA with SAH. One patient with a superior cerebellar DA presented with a midbrain infarct developed SAH with spontaneous occlusion of the aneurysm two weeks later. Of the 14 cases, ten were angiographically stable or cured during a follow up period of four to 70 months. one spontaneously resolved and two recurred. There was one death.

We performed various ophthalmic investigations in order to confirm the diagnosis and document the various features of posterior microphthalmos in a 21-year-old male. Ophthalmic examination revealed low vision with high hyperopia, papillomacular folds, midperipheral pigmentary changes and crowded optic discs. The optic discs were small and crowded with increased nerve fiber layer thickness. Fundus fluorescein angiography showed reduced diameter of a capillary free zone. Anterior segment (AS) optical coherence tomography demonstrated near normal anterior chamber depths, but markedly diminished anterior chamber angles. In spite of the increased corneal thickness and steep corneas, lens thickness and endothelial cell counts were normal. Sclerochoroidal thickening and foreshortening of the globes were detected with B-scan ultrasonography. Electroretinographic findings and visual field tests were similar to those in pigmentary retinopathy. Posterior microphthalmos is a complex eye disorder, which affects predominantly the posterior segment but also involves the AS of the eye.

Alkin, Zeynep; Ozkaya, Abdullah; Karakucuk, Yalcin; Demirok, Ahmet

We performed various ophthalmic investigations in order to confirm the diagnosis and document the various features of posterior microphthalmos in a 21-year-old male. Ophthalmic examination revealed low vision with high hyperopia, papillomacular folds, midperipheral pigmentary changes and crowded optic discs. The optic discs were small and crowded with increased nerve fiber layer thickness. Fundus fluorescein angiography showed reduced diameter of a capillary free zone. Anterior segment (AS) optical coherence tomography demonstrated near normal anterior chamber depths, but markedly diminished anterior chamber angles. In spite of the increased corneal thickness and steep corneas, lens thickness and endothelial cell counts were normal. Sclerochoroidal thickening and foreshortening of the globes were detected with B-scan ultrasonography. Electroretinographic findings and visual field tests were similar to those in pigmentary retinopathy. Posterior microphthalmos is a complex eye disorder, which affects predominantly the posterior segment but also involves the AS of the eye. PMID:24791113

Alkin, Zeynep; Ozkaya, Abdullah; Karakucuk, Yalcin; Demirok, Ahmet

A variety of surgical approaches to the posterior third ventricle and pineal region exist. The choice of approach is influenced by the exact location of the lesion, its expected pathologic findings, and the comfort level of the operating surgeon with the approach that is being considered. For most pineal region masses that are situated in the midline below the deep venous system, we favor the supracerebellar-infratentorial approach in the sitting position. For pineal region lesions that displace the deep venous system inferiorly or have significant lateral extension, we prefer the occipital-transtentorial approach in the three-quarter prone or sitting position. For lesions that are truly in the posterior third ventricle without extension posterior to the splenium, we prefer the interhemispheric-transcallosal approach in the lateral position. PMID:15024799

The supracerebellar transtentorial (SCTT) approach, a modification of the infratentorial supracerebellar approach, facilitates simple and minimally invasive access to posterior temporomedial structures without requiring retraction of the temporal or occipital lobe. The SCTT approach was used in 16 patients over a 3-year period. Eleven patients harbored tumors confined to, or located mainly within, the posterior hippocampal formation, three patients harbored aneurysms (one ruptured posterior cerebral artery [PCA] aneurysm at the P2-P3 junction, one ruptured giant PCA [P2] aneurysm, and one giant basilar artery-superior cerebellar artery aneurysm), one patient had juvenile-type moyamoya disease, and one patient suffered from medically intractable epilepsy. In these patients, the SC PMID:11565884

Tonsillectomy is one of the most common operations performed by otolaryngologists. Some extraordinary complications of this surgery are massive bleeding, taste perception disorders due to glossopharyngeal nerve damage, hematoma of the mouth floor, jugular vein thrombosis, Grisel syndrome, cervical osteomyelitis, nasopharyngeal stenosis, pulmonary edema, infection, and lingual artery pseudoaneurysm. In this clinical report, an 8-year-old girl presented with a posterior plica perforation after adenotonsillectomy performed 1 week previously and this complication has led to velopharyngeal insufficiency. This rare complication may result from traumatic damage or excessive cauterization of the posterior plica. PMID:25006950

Yildirim, Yavuz Selim; Senturk, Erol; Ozturan, Orhan

Hydatidosis is an endemic affection in Tunisia. Cerebral echinococcosis is a relatively rare entity accounting for only 1-2% of all hydatid cysts in humans. Extradural hydatid cyst of the posterior fossa is a very uncommon site for the disease. We report the case of a four-year-old child admitted for high intracranial pressure. Brain CT scan showed an extradural posterior fossa cyst without enhancement after contrast medium injection. Operative finding revealed a hydatid cyst. The histological examination of the tissue sample confirmed the diagnosis. The patient was given albendazole post operatively. She feels well six months later. PMID:17434701

Braham, E; Bellil, S; Bellil, K; Chelly, I; Mekni, A; Haouet, S; Kchir, N; Khaldi, M; Zitouna, M

The pathogenesis of acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is not fully understood. Some believe it to be a primary dysfunction of the retinal pigment epithelium while others assume that its development follows a choroidal vasculitis. It generally presents as a bilateral condition and shows no sex predilection. The visual prognosis is generally good, though severe and permanent visual loss occasionally occurs. The funduscopic presentation consists of multiple flat, yellow-white lesions of the posterior pole at the level of the retinal pigment epithelium. This paper discusses a case of APMPPE and reviews and summarizes the current literature on this disorder. PMID:3819293

Abstract Some students are less accurately measured,by typical reading tests than other students. By asking teachers to identify students whose performance,on state reading tests would likely underestimate their reading skills, this study sought to learn about characteristics of less accurately measured,students while also evaluating how well teachers can make such judgments. Twenty students identified by eight teachers participated in structured

Ross Moen; Kristi Liu; Martha Thurlow; Adam Lekwa; Sarah Scullin; Kristin Hausmann

We find an accurateprobability density function for Monte Carlo sampling of a Gaussian laser beam, which can be used to accurately model light transport in tissue. It is shown that our proposed method is accurate by comparing to the exact solution made by the convolution

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.

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

Estimates of the magnetotelluric transfer functions can be viewed as ratios of two complex random variables. It is assumed that the numerator and denominator are governed approximately by a joint complex normal distribution. Under this assumption, probability distributions are obtained for the magnitude, squared magnitude, logarithm of the squared magnitude, and the phase of the estimates. Normal approximations to the distributions are obtained by calculating mean values and variances from error propagation, and the distributions are plotted with their normal approximations for different percentage errors in the numerator and denominator of the estimates, ranging from 10% to 75%. The distribution of the phase is approximated well by a normal distribution for the range of errors considered, while the distribution of the logarithm of the squared magnitude is approximated by a normal distribution for a much larger range of errors than is the distribution of the squared magnitude. The distribution of the squared magnitude is most sensitive to the presence of noise in the denominator of the estimate, in which case the true distribution deviates significantly from normal behavior as the percentage errors exceed 10%. In contrast, the normal approximation to the distribution of the logarithm of the magnitude is useful for errors as large as 75%.

We report a case of 19-year-old asymptomatic man with posterior mediastinal mass thought to be of neurogenic origin on computed tomography scan. During video-assisted thoracic surgery the mass appeared to be an extralobar pulmonary sequestration. Surgery was straightforward by division of vascular pedicle. Histopathology confirmed diagnosis. PMID:15172305

Posterior fossa arachnoid cysts are more common than previously reported. While they may present with symptoms of hearing loss, vertigo, and tinnitus, often they are associated with vague, nonspecific complaints such as headache, dizziness, or generalized unsteadiness. We present five cases of posterior fossa arachnoid cysts discovered in adult patients. Four of the five patients had nonlocalizing symptoms (three of those sought medical evaluations for persistent dizziness and/or headache). Two patients had prolonged symptoms despite medical evaluation and normal audiometric testing before the correct diagnosis was made. We describe the case of our senior author (C.P.D.) in detail and include computerized tomographic and nuclear magnetic resonance studies outlining his pathology. A review of the management of these lesions is included. Dizzy patients and those patients with nonspecific complaints referable to the inner ear or posterior fossa who have normal audiometric testing, and in whom the index of suspicion is high, should have high resolution computerized tomography of the posterior fossa. PMID:3999903

Hadley, M N; Grahm, T W; Daspit, C P; Spetzler, R F

Dermoid tumours in children usually occur in two locations: at the anterior fontanelle and on the occipital squama. An exceptional site of origin for a posterior fossa dermoid cyst is the extradural space. There are only six previous cases of this situation reported in the literature. A series of 103 subscalp and calvarial masses in children were reviewed and three

Dermoid cysts of the posterior fossa are uncommon. When associated with a dermal sinus, these cysts are often diagnosed during early childhood. The main risk of such an association is contamination of the cyst leading to abscedation of the dermoid itself or formation of daughter abscesses within the cerebellar hemisphere. We recently treated a 20-month-old girl who had a congenital

I. H. Tekkök; M. J. Higgins; E. C. G. Ventureyra; S. S. Baeesa

A 35 year old man presented with the sudden onset of left leg pain and swelling. Empirical anticoagulation for presumed deep vein thrombophlebitis was followed by acute worsening of symptoms. On further evaluation the patient was found to have a ruptured Baker's cyst and an acute posterior compartment syndrome. PMID:2256746

Medulloblastoma of the cerebellum is a common intracranial neoplasm in children and presents many faces in medical imaging. Characteristic or classic features, such as increased attenuation on unenhanced CT, midline location and well defined margins, are commonly present in childhood cases of posterior foassa medulloblastoma, although atypical imaging features are being noted more frequently with the increased dependence on MR

The aim of this study was to investigate the audiovestibular deficits in those with posterior fossa epidermoid cyst including cerebellopontine angle in two patients and cerebellum in one patient. Prior to operation, all three patients showed bilateral gaze nystagmus. Audiometry revealed mild hearing loss in two patients, and caloric test displayed canal paresis in two patients. After operation, subsidence of

Posterior scleritis is an uncommon condition that usually occurs in adults and the diagnosis is often missed. It is even more rare in children. We report five cases of the disease in children. The patients presented with severe pain in an inflamed eye and usually had orbital signs with lid swelling and limitation of extraocular movements; four of the five

One of the most difficult areas to visualize in brain scanning is the posterior fossa and its adjacent areas. Other authors ( 1, 2 ) have reported relative inability to consistently visualize abnormalities in this region. It is the purpose of this paper to present a simple scanning technique which has proven of value to us in scanning this region

We report an unusual case of true atherosclerotic posterior tibial artery (PTA) aneurysm without any apparent causative history. To our knowledge, in the English Literature only seven previously cases of true PTA aneurysms are reported. Due to its location, this lesion may require surgical intervention and removal. The presentation, the diagnostic evaluation, and the surgical management of the aneurysm are discussed.

Robaldo, Alessandro; Di Iasio, Giacomo; Testi, Gabriele; Colotto, Patrizio

MRI is a useful tool to complement US for imaging of the fetal posterior fossa (PF). In France, the discovery of a PF malformation in the fetus frequently leads to termination of pregnancy (80% in a personal series). However, despite improved accuracy in the diagnosis of PF abnormalities, prognosis remains uncertain. The first objective of this review is to document

Catherine Adamsbaum; Marie Laure Moutard; Christine André; Valérie Merzoug; Solène Ferey; Marie Pierre Quéré; Fanny Lewin; Catherine Fallet-Bianco

Rarely, a solitary posterior inferior cerebellar artery (PICA) will supply both cerebellar hemispheres. We report four cases of this variant. We present a retrospective review of clinical information and imaging of patients undergoing angiography at our institution to identify patients with a bihemispheric PICA. There were four patients: three males and one female. One patient presented with a ruptured arteriovenous

Sean P. Cullen; Augustin Ozanne; Hortensia Alvarez; Pierre Lasjaunias

Nine athletes (seven football offensive linemen, one defensive lineman, and one lacrosse player) were found at arthroscopy to have posterior labral detachment from the glenoid. In our series, this lesion is specific to contact athletes who engage their opponents with arms in front of the body. All patients had pain with bench pressing and while participating in their sport, diminishing

Scott D. Mair; Robert “Hap” Zarzour; Kevin P. Speer

A 20-year-old female presented with distorted vision after a viral illness and was found to have acute posterior multifocal placoid pigment epitheliopathy (APMPPE). This case is described with presenting signs and symptoms and the final outcome. The general features and aetiology of APMPPE are discussed. PMID:12482320

A patient of posterior cortical atrophy, characterized by early signs of progressive visual agnosia documented by repeated neuropsychological tests, is reported. SPECT and MRI findings showed left unilateral parieto-occipital involvement in the earlier stage. A PET study executed eight months later showed bilateral parieto-occipital hypometabolism, but predominantly in the left hemisphere. This suggests that the degeneration may have developed asymmetrically,

Masafumi Mizuno; Giuseppe Sartori; Davide Liccione; Lorella Battelli; Rosario Campo

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

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

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

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.

In the global description of eternal inflation, probabilities for vacua are notoriously ambiguous. The local point of view is preferred by holography and naturally picks out a simple probability measure. It is insensitive to large expansion factors or lifetimes and so resolves a recently noted paradox. Any cosmological measure must be complemented with the probability for observers to emerge in

Objective:The aim of this study was to evaluate the short- and long-term seizure outcome and to find predictors of outcome after epilepsy surgery in lesional posterior cortical epilepsies (PCEs).Methods:The operative outcome in 80 consecutive adult patients with lesional PCEs who underwent resective surgery for intractable partial epilepsy between 1991 and 2006 was retrospectively studied.Results:The probability of remaining in Engel Class

A E Elsharkawy; N M F El-Ghandour; F Oppel; H Pannek; R Schulz; M Hoppe; F G Woermann; M Nayel; A Issa; A Ebner

This paper introduces a new multipass algorithm for efficiently computing direct illumination in scenes with many lights and complex occlusion. Images are first divided into 8 x 8 pixel blocks and for each point to be shaded within a block, a probability density function (PDF) is constructed over the lights and sampled to estimate illumination using a small number of shadow rays. Information from these samples is then aggregated at both the pixel and block level and used to optimize the PDFs for the next pass. Over multiple passes the PDFs and pixel estimates are updated until convergence. Using aggregation and feedback progressively improves the sampling and automatically exploits both visibility and spatial coherence. We also use novel extensions for efficient antialiasing. Our adaptive multipass approach computes accurate direct illumination eight times faster than prior approaches in tests on several complex scenes. PMID:16640249

Donikian, Michael; Walter, Bruce; Bala, Kavita; Fernandez, Sebastian; Greenberg, Donald P

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.

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

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

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

This article presents the minimum 2-year results (range, 24 to 54 months) of 21 arthroscopically assisted posterior cruciate ligament\\/posterior lateral complex (PCL\\/PLC) reconstructions, evaluated preoperatively and postoperatively using the Tegner, Lysholm, and Hospital for Special Surgery knee ligament rating scales, and the KT 1000 knee ligament arthrometer (Medmetric Corp., San Diego, CA, U.S.A.). There were 15 male and 6 female

Gregory C. Fanelli; Bradley F. Giannotti; Craig J. Edson

Further to our previous work on the development of a general constitutive framework for transversely isotropic viscohyperelasticity (Limbert, G, Middleton, J. A transversely isotropic viscohyperelastic material. Application to the modelling of biological soft connective tissues. Int J Solids Struct 2004;41(15):4237-60.), we propose a phenomenological constitutive law to describe the anisotropic viscohyperelastic behaviour of the human posterior cruciate ligament (PCL) at high strain rates. The mechanical formulation is based on the definition of a Helmholtz free energy function containing a hyperelastic and a viscous potential. The equations are valid for arbitrary kinematics and satisfy elemental thermodynamic principles. Identification of the constitutive model with experimental data obtained from human PCL specimens was performed and showed the ability of the model to capture accurately the mechanical characteristics of the PCL at various strain rates. Influence of the isotropic and directional viscous stress responses on the global mechanical response are discussed in connection with the modelling hypotheses. This work was motivated by the need to provide an accurate constitutive model of the PCL to be used in finite element analyses of human occupants in car crash simulations. Besides uniaxial tests along the natural fibre orientation of the PCL, additional tests such as equibiaxial, strip biaxial compression-tension and shear tests were also performed in order to assess the physical response of the model in different loading situations. It was found that the model performed as well in these conditions. PMID:15919227

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

BACKGROUND: The posterior genes of the HoxD cluster play a crucial role in the patterning of the tetrapod limb. This region is under the control of a global, long-range enhancer that is present in all vertebrates. Variation in limb types, as is the case in amphibians, can probably not only be attributed to variation in Hox genes, but is likely

We analyse the thesis of Kummerer and Maassen (1996) that classical probability is unable to model the the stochastic nature of the Aspect experiment, in which violation of Bell's inequality was experimentally demonstrated. Accord- ing to these authors the experiment shows the need to introduce the extension of classical probability known as Quantum Probability. We show that their argu- ment

Of 700 neonates examined by computed tomography (CT) in a 4 years period, 17 were found to have a posterior fossa hemorrhage. Eleven were born at term, and six were premature. Delivery was traumatic in 12 babies. The hematoma was in the subdural space in nine and within the cerebellum in eight. The CT diagnosis of extravasated blood in the posterior fossa is easy both in full-term neonates and prematures. The localization of the hematoma, however, may be difficult. While in the full-term neonates differentiation between subdural and intracerebellar location is relatively easy, in the premature the cerebellar hematoma frequently has a crescentic shape that resembles a subdural collection. Four patients with a subdural hematoma and four with a cerebellar hematoma were operated on. The general prognosis is poor: seven patients died; of the survivors, only three are normal at follow-up. PMID:7240500

Scotti, G; Flodmark, O; Harwood-Nash, D C; Humphries, R P

Autonomic dysreflexia is a syndrome of massive imbalanced reflex sympathetic discharge in patients who had a spinal cord injury above the splanchnic sympathetic outflow resulting in a sudden increase in blood pressure. Posterior reversible encephalopathy syndrome (PRES) refers to a clinicoradiologic entity characterized by headache, consciousness impairment, visual disturbances, seizures, and posterior transient changes on neuroimaging (cerebral vasogenic edema). Hypertension is a common cause of PRES. The authors describe two case reports of patients with tetraplegia who developed PRES after an autonomic dysreflexia episode. One of them had recurrence of PRES in a similar clinical context. The authors discuss further aspects of PRES and its recurrence, which seems to be unusual particularly after autonomic dysreflexia. PMID:23117272

Matias, Ana Catarina; Rocha, João; Cerqueira, Maria Emília; Pereira, João Manuel

Nonpenetrating or blunt ocular trauma, orbital trauma and systemic trauma may cause a variety of posterior segment abnormalities. Blunt ocular trauma may cause damage to the retina (commotio retinae), retinal pigment epithelium (retinal pigment epithelial edema), choroid (choroidal rupture) and optic nerve (optic nerve evulsion) alone or in combination. Traumatic macular holes and retinal detachment or dialysis may also occur after blunt ocular trauma. Trauma to the orbital tissues adjacent to the globe can cause concussive forces with damage to multiple structures within the eye (chorioretinitis sclopetaria). Systemic trauma may result in diffuse retinopathy (Purtscher's retinopathy, shaken baby syndrome) or localized retinal abnormalities (whiplash retinopathy, fat embolism syndrome). Alterations in intravascular (Valsalva retinopathy) or intracranial pressure (Terson's syndrome) due to a variety of causes may result in preretinal or vitreous hemorrhage and associated visual loss. The purpose of this report is to review each of these entities of traumatic posterior segment abnormalities. PMID:2191381

Delivery in occiput posterior position is associated with a higher risk of cesarean section, operative vaginal delivery and severe perineal tears. We report the technic of manual rotation described by Tarnier and Chantreuil and used daily in our maternity center. Only five studies were published on this topic; all of them demonstrate that manual rotation decreases the risk of cesarean section. Moreover, it could decrease the risk of prolonged second stage, chorioamnionitis and third and fourth degree tears in comparison with expectant management. However, manual rotation is associated with a two-fold higher risk of cervical and vaginal lacerations. Manual rotation performed with an adequate technic is an efficient and safe manœuvre to avoid complications associated with occiput posterior vaginal delivery. PMID:21924659

We describe a very rare case of mature posterior fossa teratoma in an adult who presented with clinico-radiological findings consistent with a dermoid cyst. A computed tomography scan showed a hypodense mass in the cistern magna with calcification and a sinus tract in the occipital bone. Magnetic resonance imaging revealed a hypo- to hyperintense mass without contrast enhancement. The intraoperative picture showed a dermal sinus and a cyst containing lipid, keratin and hair. Histopathological examination showed a tumor with components of all the three germ layers; thereby, a diagnosis of mature teratoma was made. The histopathological differentiation between teratoma and dermoid cyst is very valuable for ruling out the presence of immature/malignant or germinomatous components that would require further adjuvant therapies. Thus, we here present a rare case of posterior fossa teratoma mimicking dermoid cyst and emphasize the importance of histopathological differentiation between these entities. PMID:23263509

Two features of eyes enucleated for posterior uveal melanoma that may serve as indicators for traumatic enucleation and relate to dissemination of tumor cells at the time of enucleation are myelin artifact of the optic nerve head and acute hemorrhage within the tumor. Myelin artifact occurs when crushed optic nerve tissue is squeezed into the eye at the time of enucleation. Intralesional hemorrhage may occur during surgery and may be correlated with fluctuations in intraocular pressure. We reviewed 519 cases of posterior uveal melanoma treated by enucleation between 1950 and 1970. Without knowledge of the follow-up data, we examined histologic sections for myelin artifact, intralesional hemorrhage, subretinal hemorrhage, Callender cell type, size of tumor, necrosis, and scleral or orbital invasion. Neither myelin artifact nor intralesional hemorrhage were independent prognostic risk factors. These findings do not support or refute the hypothesis that excessive trauma during enucleation results in a worse prognosis. PMID:2240138

Ankle arthroscopy provides a minimally invasive approach to the diagnosis and treatment of certain ankle disorders. Neurological complications resulting from ankle arthroscopy have been well documented in orthopaedic and podiatric literature. Owing to the superficial location of the ankle joint and the abundance of overlying periarticular neurovascular structures, complications reported in ankle arthroscopy are greater than those reported for other joints. In particular, all reported neurovascular injuries following ankle arthroscopy have been the direct result of distractor pin or portal placement. The standard posteromedial portal has recognized risks because of the proximity of the posterior neurovascular structures. There can be considerable variability in the course of these portals and their proximity to the neurovascular structures. We found one report of intra-articular damage to the posterior tibial nerve as a result of ankle arthroscopy in the English-language literature and we report this paper as a second case described in the literature. PMID:17618442

Temporomandibular disorders (TMD) include craniocervical pain conditions with unclear etiologies. Central changes are suspected; however, few neuroimaging studies of TMD exist. Single-voxel proton magnetic resonance spectroscopy (1H-MRS) was used before and after pressure-pain testing to assess glutamate (Glu), glutamine (Gln), N-acetylaspartate (NAA), and choline (Cho) levels in the right and left posterior insulae of 11 individuals with myofascial TMD and

G. E. Gerstner; R. H. Gracely; A. Deebajah; E. Ichesco; A. Quintero; D. J. Clauw; P. C. Sundgren

Background The reversible posterior leukoencephalopathy syndrome is a clinical/radiological syndrome characterized by headache, seizures, impaired vision, acute hypertension, and typical magnetic resonance imaging findings. There are several reports in the literature that depict its occurrence in cancer patients. The list of common anticancer and supportive care drugs that predispose to reversible posterior leukoencephalopathy syndrome is expanding and includes not only a large number of chemotherapeutic agents but also an increased number of new targeted drugs, particularly angiogenesis inhibitors such as bevacizumab,sorefenib and sunitinib. Pazopanib is an oral tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and c-Kit which after a positive phase III randomized clinical trial in patients with advanced renal cell cancer received FDA approval for the treatment of advanced renal cell carcinoma. Until now no cases of reversible posterior leukoencephalopathy syndrome induced by pazopanib have been reported. Case report We present the case of a 40 years old female patient with heavily pre-treated metastatic renal cell carcinoma who received pazopanib as salvage treatment. After 21 days of pazopanib therapy the patient referred to the emergency department with epileptic seizure, impaired vision at both eyes and headache. MRI of the brain revealed subcortical oedema at the occipital and parietal lobes bilaterally. She was treated with anticonvulsants, i.v. administration of mannitol and antihypertensives and she recovered completely from her symptoms and was discharged on the tenth hospital day. A brain MRI performed 3 weeks after showed that the subcortical oedema had been subsided. Conclusion In conclusion this is the first case of pazopanib induced reversible posterior leukoencephalopathy syndrome. Although usually reversible, this syndrome is a serious and potentially life threatening adverse effect, if untreated, that should be considered by physicians treating metastatic renal cell carcinoma patients with pazopanib.

2 cases of posterior fossa arachnoid cyst are discussed. In the first, it is likely that perinatal factors were responsible for the temporal lobe pathology and the formation of the cyst. Progressive dilatation of the temporal horn may have then been caused by obstruction from the cyst. In the second case, minor head trauma was a possible mechanism for the cyst production, although it seemed irrelevant to the mode of clinical presentation. PMID:756011

PURPOSE : To describe the systemic and visual characteristics and prognosis in patients with posterior ischemic optic neuropathy (PION).DESIGN : Observational case series.METHODS : Retrospective chart review in a multicenter setting. Seventy-two patients (98 eyes) with a clinical diagnosis of PION. Co-morbid systemic diseases and visual function were recorded at both initial presentation and after mean visual follow-up of 4.1

Srinivas R. Sadda; Michelle Nee; Neil R. Miller; Valerie Biousse; Nancy J. Newman; Anthony Kouzis

Posterior urethral valves (PUV) are now commonly suspected on antenatal ultrasound, but can present with a broad spectrum of severity postnatally. Rarely, the diagnosis is missed until adolescence or adulthood when the patient usually presents with lower urinary tract symptoms. We describe an even rarer case of PUV in a late adolescent who first presented with preserved renal function and urinary incontinence. We review the literature on presentation, natural history and outcomes of both early and late presenting PUV cases. PMID:23094222

Posterior urethral valves (PUV) are now commonly suspected on antenatal ultrasound, but can present with a broad spectrum of severity postnatally. Rarely, the diagnosis is missed until adolescence or adulthood when the patient usually presents with lower urinary tract symptoms. We describe an even rarer case of PUV in a late adolescent who first presented with preserved renal function and urinary incontinence. We review the literature on presentation, natural history and outcomes of both early and late presenting PUV cases.

This study retrospectively reviewed our experience in the diagnosis of six patients with posterior fossa lymphoma during the\\u000a past decade. Initial manifestation included vertigo in all patients (100%) and ataxia in 4 (67%), with a mean duration of\\u000a 40 days. Audiometry revealed sensorineural hearing loss in five patients (83%). Gaze-evoked nystagmus was also noted in five\\u000a patients (83%). Electronystagmography (ENG)

Mediastinal teratomas are rarely reported in children. We report a 12-year-old child, diagnosed and treated as empyema thoracis in a peripheral setting for 18 months. In our centre, CT scan performed revealed a well circumscribed multiloculated cystic lesion containing fat, bone and teeth, suggestive of a teratoma. The mass was excised and found to be an infected posterior mediastinal teratoma, confirmed on histopathology.

The random finite set (RFS) approach offers a natural and smart means to model multi-target and measurements received by the multi-sensor. The probability hypothesis density (PHD) filter propagates a multi-target statistical first moment, the PHD in place of the full multi-target posterior distribution. But there is no closed form solution to the PHD recursion. The Gaussian mixture probability hypothesis density

Posterior capsular contracture is a common cause of shoulder pain in which the patient presents with restricted internal rotation and reproduction of pain. Increased anterosuperior translation of the humeral head occurs with forward flexion and can mimic the pain reported with impingement syndrome; however, the patient with impingement syndrome presents with normal range of motion. Initial management of posterior capsular contracture should be nonsurgical, emphasizing range-of-motion stretching with the goal of restoring normal motion. For patients who fail nonsurgical management, arthroscopic posterior capsule release can result in improved motion and pain relief. In the throwing athlete, repetitive forces on the posteroinferior capsule may cause posteroinferior capsular hypertrophy and limited internal rotation. This may be the initial pathologic event in the so-called dead arm syndrome, leading to a superior labrum anteroposterior lesion and, possibly, rotator cuff tear. Management involves regaining internal rotation such that the loss of internal rotation is not greater than the increase in external rotation. In the athlete who fails nonsurgical management, a selective posteroinferior capsulotomy can improve motion, reduce pain, and prevent further shoulder injury. PMID:16675620

Airbags indeed reduce the risk of injury and death in motor vehicle accidents, however, ocular injury induced by airbag deployment has been reported. From 1999 to 2001, medical records were retrospectively reviewed for patients with severe ocular injury related to airbag inflation at Taipei Veterans General Hospital. The ocular presentation, clinical course, management and visual outcome were recorded and studied in detail. Three cases of ocular posterior segment injury associated with airbag inflation were identified. Mean age was 37.3 years old (range 34-39 years). None of the patients was wearing a seat belt. All patients had periocular contusion, corneal edema, and hyphema. Vitreous hemorrhage was found in 3 cases, and there were 2 cases with severe macular injury, including traumatic maculopathy and hypotony maculopathy. Retinal detachment developed in 1 case. One patient presented with traumatic macular hole 6 weeks after injury. The initial visual acuity was hand motion only in all patients, the final visual outcomes recovered to 6/20, 1/60 and 2/60, respectively. The airbag-associated posterior segment ocular trauma was induced by impact with fully deployed airbag. Severe ocular posterior segment trauma with devastating visual sequelae might occur in drivers and passengers who have not fastened their seat belt. PMID:15553805

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.

(Full text is available at http://www.manu.edu.mk/prilozi). With the introduction of new techniques in diagnostic and interventional radiology and progress in micro-neurosurgery, accurate knowledge of the brain blood vessels is essential in daily clinical work. The aim of this study was to describe the different types of PCA origin, their diameter, and to emphasize their clinical significance. In this study we examined radiographs of 53 patients who had CT angiography undertaken for a variety of clinical reasons, performed as a part of their medical treatment at the University Radiology Clinic in Skopje, R. Macedonia. This study included 24 females and 29 males, ranging in age from 32 to 73 years; mean age 55.3 ± 11.5 years. The results showed that the diameter of the posterior cerebral artery was 1.74 ± 0.317 mm on the right side and 1.98 ± 0.408 mm on the left side. The adult configuration was present in 37 (69.81%); foetal configuration was present in 12 (22.64%) and transitional configuration was present in 4 (7.54%) of the patients. We found two patients with bilateral foetal type and ten with unilateral foetal type (six on the right side and four on the left side). Despite the limitations of the study, we found that the foetal variant was presented in 22.64% of patients. Thorough knowledge of the anatomy of the intracranial vessels is important to clinicians as well as basic scientists who deal with problems related to intracranial vasculature on a daily basis. Key words: posterior cerebral artery, anatomy, variations, circle of Willis. PMID:24798602

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

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

Tracking multiple targets with uncertain target dynamics is a difficult problem, especially with nonlinear state and\\/or measurement equations. With multiple targets, representing the full posterior distribution over target states is not practical. The problem becomes even more complicated when the target number varies, in which case the dimensionality of the state space itself becomes a discrete random variable. The Probability

The probability hypothesis density (PHD) filter, which propagates only the first moment (or PHD) instead of the full target posterior, has been shown to be a computationally efficient solution to multi-target tracking problems. Incorporating the current statistical model that is effective in dealing with the maneuvering motions, this paper proposes a current statistical model PHD (CSMPHD) filter for multiple maneuvering

The probability hypothesis density (PHD) filter is a practical alternative to the optimal Bayesian multi-target filter based on random finite sets. It propagates the posterior intensity (or a first-order moment) of the random sets of targets, from which the number as well as individual states can be estimated. Furthermore, a number of sequential Monte Carlo (SMC) approximations of the PHD

Time accurate CFD may offer a faster approach to S&C aerodynamic database population than the conventional point by point steady state CFD. We would directly simulate -, -sweeps or other configuration movements typically of measurement sequence in wind tunnels. A second objective is to demonstrate potential applications to assessment of S&C dynamic derivatives by simulating vehicle motions such as free to roll, and nonlinearity such as the trends of aerodynamic forces near CL-max or flow hysteresis.

Aseptic meningitis is a recognised complication after posterior fossa surgery. It is often self limiting but occasionally runs a protracted course requiring repeated CSF examination to exclude infection, and treatment with systemic steroids. A patient is described with aseptic meningitis after posterior fossa surgery who underwent posterior fossa re-exploration nearly 3 years after the initial operation. This disclosed a pseudomeningocele,

C E M Hillier; A Penrose Stevens; F Thomas; J Vafidis; R Hatfield

Fourteen hydrocephalic children with functioning lateral ventricular shunts developed posterior fossa problems: posterior fossa cyst (7 patients); isolated fourth ventricle (6 patients), and concomitant dilatation of third and fourth ventricles (1 patient). Posterior fossa symptoms were present in only 2 children; 10 had nonspecific symptoms and 2 were asymptomatic. Computed tomography was the most useful investigation for diagnosis and management.

D. H. Parikh; P. K. H. Tam; H. Carty; R. E. Cudmore

We show that probability-based environmental resource monitoring programs, such as U.S. Environmental Protection Agency's (U.S. EPA) Environmental Monitoring and Asscssment Program EMAP) can be analyzed with a conditional probability analysis (CPA) to conduct quantitative probabi...

Previous studies have suggested that the general public misinterprets probability of precipitation (PoP) forecasts, leading some meteorologists to argue that probabilities should not be included in public weather forecasts. Upon closer examination, however, these studies prove to be ambiguous with regard to the nature of the misunderstanding. Is the public confused about the meaning of the probabilities or about the definition of the event to which the probabilities refer? If event misinterpretation is the source of the confusion, then elimination of the probabilities would not reduce the level of misunderstanding.The present paper summarizes a study of 79 residents of Eugene, Oreg., who completed a questionnaire designed to investigate their understanding of and attitude toward precipitation probability forecasts. Results indicate that the event in question frequently is misunderstood, with both traditional precipitation forecasts and PoP forecasts producing similar levels of event misinterpretation. On the other hand, the probabilities themselves are well understood. Moreover, most respondents revealed a preference for the use of probabilities to express the uncertainty inherent in precipitation forecasts. Although the sample size was limited, the results of this study strongly support the inclusion of probabilities in public forecasts of precipitation occurrence. The paper concludes with a brief discussion of some implications of these results for operational weather forecasting.

Murphy, Allan H.; Lichtenstein, Sarah; Fischhoff, Baruch; Winkler, Robert L.

Observing any violation of the Equivalence Principle at a level as low as 10 -15 needs both a very soft and stable environment and a very accurate instrument The MICROSCOPE space laboratory allows testing of the universality of free fall with two masses made of a Platinum Rhodium alloy and a Titanium alloy in a 10 pico-g environment The two test-masses are accurately controlled by electrostatic forces to follow a common geodesic within a CNES drag-free microsatellite Accurate centring and alignment of the test-masses is mandatory to prevent any artefact signal due to the Earth s gravity gradient or any on-board gravity gradient To this purpose the MICROSCOPE instrument called Twin-Space Accelerometer for Gravitation Experimentation T-SAGE has been designed to minimise the gravity gradient disturbances A laboratory model and a first representative model for vibration tests have been produced integrated and tested These models have allowed verification of the manufacturing and integration processes and of their accuracy which gives a first budget for the expected centring and alignment of the flight-models This paper describes the micro-meter machining and integration challenges of T-SAGE and their impact on the instrument performance In particular the shape of the test-mass has an effect on the differential accelerometer output due to the gravity gradient and also on the instrument capacitive position output used for the electrostatic servo-loop First results obtained with the fully integrated models are also presented to assess the

Rodrigues, M.; Touboul, P.; Chhun, R.; Hudson, D.; Foulon, B.; Flinoise, P.; Bodoville, G.; Lebat, V.

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.

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

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.

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 JØrgen Jacobsen; Birgitte Sloth; TORBEN TRANAES

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…

For a transpont theory multi-group and multi-zone calculation of the ; neutron flux in a cylindrical reactor cell, one needs the probabilities that a ; neutron arising in an arbitrary ring zone makes its next collision in another ; arbitrary ring zone. These probabilities were calculated for source densities ; which are isotropic and can be developed in a straight

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

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,…

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.

Purpose To determine if transfer to only the anterior branch of the axillary nerve will restore useful function following axillary nerve injury with persistent posterior deltoid and teres minor paralysis. Methods We used a computational musculoskeletal model of the upper limb to determine the relative contributions of posterior deltoid and teres minor to maximum joint moment generated during a simulated static strength assessment and to joint moments during 3 sub-maximal shoulder movements. Movement simulations were performed with and without simulated posterior deltoid and teres minor paralysis to identify muscles which may compensate for their paralysis. Results In the unimpaired limb model, teres minor and posterior deltoid accounted for 16% and 14% of the total isometric shoulder extension and external rotation joint moments, respectively. During the 3 movement simulations, posterior deltoid produced as much as 20% of the mean shoulder extension moment, while teres minor accounted for less than 5% of the mean joint moment in all directions of movement. When posterior deltoid and teres minor were paralyzed, the mean extension moments generated by the supraspinatus, long head of triceps, latissimus dorsi, and middle deltoid increased to compensate. Compensatory muscles were not fully activated during movement simulations when posterior deltoid and teres minor were paralyzed. Conclusions Reconstruction of the anterior branch of the axillary nerve only is an appropriate technique for restoring shoulder abduction strength following isolated axillary nerve injury. When shoulder extension strength is compromised by extensive neuromuscular shoulder injury, reconstruction of both the anterior and posterior branches of the axillary nerve should be considered. Clinical Relevance By quantifying the biomechanical role of muscles during sub-maximal movement, in addition to quantifying muscle contributions to maximal shoulder strength, we can inform pre-operative planning and permit more accurate predictions of functional outcomes.

Crouch, Dustin L.; Plate, Johannes F.; Li, Zhongyu; Saul, Katherine R.

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. Posteriorprobabilities 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

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

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

Summary We compute an accurate approximation to the probability of fixation for a beneficial mutation in a population fluctuating with a stationary distribution of population size. The population dynamics are described by the theta-logistic model with environmental variance, assuming that the population size is large enough to ignore demographic variance. We show that stochastic fluctuations of population size reduce the

This paper investigates three major issues regarding the elicitation of expert knowledge for economic risk analysis: (1) recognition of some of the implicit assumptions and beliefs; (2) development of an approach to elicit expert knowledge as accurate, calibrated and coherent subjective probabilities; and (3)a study to explore human ability to predict future events and the validity of the implicit assumptions

Posterior nutcracker syndrome (PNS) is a rare condition due to left renal vein (LRV) hypertension, caused by compression of the LRV between the vertebral column and the abdominal aorta. Diagnosis of PNS is challenging, as symptoms are variable and not specific. Therapeutic options are debated, and either conservative, open, or endovascular approaches have been advocated as both safe and effective. We report our experience with a case of PNS in a 17-year-old woman, who presented with a 2 year history of recurrent hematuria associated to severe left flank and back pain, successfully treated with anterior transposition of the LRV. PMID:21458199

Reversible posterior leukoencephalopathy syndrome (RPLS) is clinical radiologic condition associated with neurological symptoms and cerebral white matter edema. It has been associated with uncontrolled hypertension, eclampsia, immunosuppressants, and more recently the use of antiangiogenic drugs. Sunitinib is an inhibitor of the vascular endothelial growth factor receptor widely used in the treatment of metastatic renal cell carcinoma (RCC). We report a rare case of RPLS occurring on therapy with sunitinib in a patient with RCC. Our aim is to highlight the importance of considering RPLS as a diagnostic possibility and to hold sunitinib for RCC patients presenting with neurologic symptoms.

Costa, Ricardo; Costa, Renata; Junior, Gilberto Moura de Brito; Cartaxo, Henrique Queiroz; de Barros, Alex Caetano

Reversible posterior leukoencephalopathy syndrome (RPLS) is clinical radiologic condition associated with neurological symptoms and cerebral white matter edema. It has been associated with uncontrolled hypertension, eclampsia, immunosuppressants, and more recently the use of antiangiogenic drugs. Sunitinib is an inhibitor of the vascular endothelial growth factor receptor widely used in the treatment of metastatic renal cell carcinoma (RCC). We report a rare case of RPLS occurring on therapy with sunitinib in a patient with RCC. Our aim is to highlight the importance of considering RPLS as a diagnostic possibility and to hold sunitinib for RCC patients presenting with neurologic symptoms. PMID:24900933

Costa, Ricardo; Costa, Rubens; Costa, Renata; Junior, Gilberto Moura de Brito; Cartaxo, Henrique Queiroz; de Barros, Alex Caetano

We studied 30 patients with opacifications of the posterior capsule to determine if the potential acuity meter (PAM) could accurately predict final visual outcome after Nd:YAG discussion. The final visual acuity was within one line of the PAM prediction in 22 of 30 patients (73%), better by two or more lines in seven patients (23%), and worse in one patient (4%) by two lines. Although in thicker capsules the final acuity was occasionally better than the PAM prediction, the rates of false negative and false positive predictions were very low. Mild cystoid macular edema (3 patients), age-related macular degeneration (3 patients), intraocular lens status, and level of initial acuity did not diminish PAM accuracy. The PAM effectively predicts final visual acuity after YAG posterior capsulotomy, when used in a patient, unhurried manner.

The methods of temporal differences (Samuel, 1959; Sutton, 1984, 1988) allow an agent to learn accurate predictions of stationary stochastic future outcomes. The learning is effectively stochastic approximation based on samples extracted from the process generating the agent's future.

The methods of temporal differences (Samuel, 1959; Sutton, 1984, 1988) allow an agent to learn accurate predictions of stationary stochastic future outcomes. The learning is effectively stochastic approximation based on samples extracted from the process generating the agent's future.

To determine the optimal width of a midline posterior spinal block (MPSB) (to avoid delivering too great a dose to the cord and too small a dose to adjacent tissue), the authors determined with magnetic resonance (MR) imaging normal ranges of cord depth and width and correlated them with film dosimetric data. In 59 randomly selected patients there was a wide range for both depth and width. The average depths of the anterior and posterior surfaces of the cord were 6.7 cm +/- 1.4 and 5.4 cm +/- 1.3, respectively. The average cord width was 1.6 cm +/- 0.4. Optimal cord block width as a function of cord width was determined for a 6-MV photon beam. The optimal cord block width at the surface (half-value layer (HVL) thickness = 6) varied from 1.5 to 3.0 cm for cord widths of 0.8-2.4 cm, which correspond to two standard deviations from the average. There was no significant dependence on depth of the cord. For optimal treatment outcome, the MPSB width may have to be determined for each patient individually.

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

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

?? Dermoid tumours in children usually occur in two locations: at the anterior fontanelle and on the occipital squama. An exceptional site of origin for a posterior fossa dermoid cyst is the extradural space. There are only six previous cases of this situation reported in the literature. A series of 103 subscalp and calvarial masses in children were reviewed and three children are reported with extradural dermoids of the posterior fossa, which communicated with the skin through midline occipital dermal sinuses. All three children were seen after the rapid growth or the formation of an abscess in a previously noted occipital subcutaneous mass present since birth. Although computed tomography or magnetic resonance imaging showed the dermal sinus and the intracranial tumour, these studies were unable to ascertain the intradural or extradural nature of the tumours, their exact origin only being established at operation. Histopathological study showed preclinical signs of infection in the two patients that had not yet formed an abscess. It is suggested that early neurosurgical treatment of these neoplasms should be done to prevent the development of severe intracranial infection. The previously reported simplicity of surgical removal of occipital extradural dermoids was not confirmed in this series.??

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.

This paper develops a hierarchical Bayes model for multiple-pass, multiple antenna synthetic aperture radar (SAR) systems with the goal of adaptive change detection. The model is based on decomposing the observed data into a low-rank component and a sparse component, similar to Robust Principal Component Analysis, previously developed by Ding, He, and Carin1 for E/O systems. The developed model also accounts for SAR phenomenology, including antenna and spatial dependencies, speckle and specular noise, and stationary clutter. Monte Carlo methods are used to estimate the posterior distribution of the variables in the model. The performance of the proposed method is analyzed using synthetic images, and it is shown that the performance is robust to a large space of operating characteristics without extensive tuning of hyperparameters. Finally, the method is applied to measured SAR data, providing competitive results compared to standard methods with the additional benefits of uncertainty characterization through a posterior distribution, explicit estimates of both foreground and background components, and flexibility in including other sources of information.

Newstadt, Gregory E.; Zelnio, Edmund G.; Hero, Alfred O., III

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.

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

Improved process design begins with using accurate physical property data. Especially in the preliminary design stage, physical property data such as density viscosity, thermal conductivity and specific heat can affect the overall performance of absorbers, heat exchangers, reboilers and pump. These properties can also influence temperature profiles in heat transfer equipment and thus control or affect the rate of amine breakdown. Aqueous-amine solution physical property data are available in graphical form. However, it is not convenient to use with computer-based calculations. Developed equations allow improved correlations of derived physical property estimates with published data. Expressions are given which can be used to estimate physical properties of methyldiethanolamine (MDEA), monoethanolamine (MEA) and diglycolamine (DGA) solutions.

Cheng, S.; Meisen, A. [Univ. of British Columbia, Vancouver, British Columbia (Canada); Chakma, A. [Univ. of Calgary, Alberta (Canada)

We calculated the probability distribution function (PDF) from simulations. The simulations were of an initially spherical wave propagated through homogeneous atmospheric turbulence. The onset of strong scintillation was calculated. The simulations' PDFs ...

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

A quantum probability measure-or quantum measurement-is said to be clean if it cannot be irreversibly connected to any other quantum probability measure via a quantum channel. The notion of a clean quantum measure was introduced by Buscemi et al. [``Clean positive operator valued measures,'' J. Math. Phys. 46(8), 082109 (2005)] for finite-dimensional Hilbert space, and was studied subsequently by Kahn [``Clean positive operator-valued measures for qubits and similar cases,'' J. Phys. A 40(18), 4817-4832 (2007)] and Pellonpää [``Complete characterization of extreme quantum observables in finite dimensions,'' J. Phys. A 44(8), 085304 (2011)]. The present paper provides new descriptions of clean quantum probability measures in the case of finite-dimensional Hilbert space. For Hilbert spaces of infinite dimension, we introduce the notion of ``approximately clean quantum probability measures'' and characterise this property for measures whose range determines a finite-dimensional operator system.

Farenick, Douglas; Floricel, Remus; Plosker, Sarah

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

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)

An elementary problem in reliability design is used to illustrate some of the principles and concerns of computational probability. Three points are made: (1) mathematically equivalent solutions may be vastly different in their suitability for numerical c...

A revised and updated bibliography on atomic transition probabilities is presented. The papers are arranged according to elements and stages of ionization, and the method employed and class of transitions are indicated behind each reference. Only articles...

Ambiguity is a measure of the level of discomfort one feels about the accuracy of the probability of an uncertain event; ambiguity is separate from the uncertainty itself. Our research has developed techniques that extend decision theory so that ambiguity...

Purpose To report clinical results and demonstrate posterior femoral translation (PFT) in medial pivot total knee arthroplasty (TKA) of posterior cruciate ligament (PCL) retaining type. Materials and methods A prospective study was performed upon thirty consecutive subjects who were operated on with medial pivot TKA of PCL retaining type between March 2009 and March 2010 and had been followed up for at least 2 years. Clinically, the knee society knee score and function score were used. In full extension and active flexion lateral radiograph, anteroposterior (AP) condylar position and magnitude of PFT was determined. Results At last follow-up, the mean knee society knee score and function score improved significantly compared to preoperative scores. The AP condylar positions were consistently posterior to midline throughout the entire range of flexion. The PFTs averaged 0.31 (±0.12) of half length of tibial base plate and were greater in higher flexion cases (r = 0.56, p = 0.0012). There were no cases having either component migration or radiolucent line wider than 2 mm except for one case showing instability related to trauma. Conclusions In medial pivot TKA of PCL retaining type, clinical outcomes were satisfactory and posterior femoral translations were consistently observed during progressive flexions of knees at two- to three-year follow-up.

Cho, Su Hyun; Cho, Hyung Lae; Lee, Soo Ho; Jin, Hong Ki

Rare earth transition probabilities are needed within the astrophysics community to determine rare earth abundances in stellar photospheres. The current work is part an on-going study of rare earth element neutrals. Transition probabilities are determined by combining radiative lifetimes measured using time-resolved laser-induced fluorescence on a slow atom beam with branching fractions measured from high resolution Fourier transform spectra. Neutral

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.

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, in the elderly, and in Asian patients. The disease can start with mild or no symptoms, but some patients progress slowly to develop symptoms of myelopathy. An accurate diagnosis through the use plain radiograph, computed tomography, and magnetic resonance imaging findings is very important to monitor the development of symptoms and to make decisions regarding a treatment plan. When symptoms are mild and non-progressive, conservative treatments and periodic observations are good enough, but once symptoms of myelopathy are present and neurologic symptoms are progressive, the treatment of choice is surgery to relieve spinal cord compression. Surgical management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be decided carefully with various considerations. The patient's neurological condition, location and extent of pathology, cervical kyphosis, presence or absence of accompanied instability, and the individual surgeon's experience must be an important factors that should be considered before surgery.

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

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

One can interpret fragmentation spectra stemming from peptides in mass-spectrometry-based proteomics experiments using so-called database search engines. Frequently, one also runs post-processors such as Percolator to assess the confidence, infer unique peptides, and increase the number of identifications. A recent search engine, MS-GF+, has shown promising results, due to a new and efficient scoring algorithm. However, MS-GF+ provides few statistical estimates about the peptide-spectrum matches, hence limiting 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 data sets. In addition, Percolator directly reports p values and false discovery rate estimates, such as q values and posterior error probabilities, for peptide-spectrum matches, peptides, and proteins, functions that are useful for the whole proteomics community. PMID:24344789

Granholm, Viktor; Kim, Sangtae; Navarro, José C F; Sjölund, Erik; Smith, Richard D; Käll, Lukas

The objective of this study was to analyze whether renal transplantation (RT) in children with posterior urethral valves (PUV) constitutes a special group with respect to groups with different etiologies of end-stage renal disease (ESRD). Between 1979 and 2004, 22 RT were performed in 19 children with PUV. The median age at RT was 10 years (range: 1.3-17). Immunosuppression was provided by triple therapy and polyclonal/monoclonal antibodies. This group was compared with the two control groups: (1) glomerulopathy (n=62) and (2) pyelonephritis/dysplasia (n=42) without lower urinary tract disease, transplanted in the same period. Ten graft losses occurred in 22 transplants: thrombosis (2), acute rejection (3), chronic graft nephropathy (2), and death of patients (3) with a functioning graft in the 1st postoperative month. We did not find significant differences versus the control group in renal function or probability of graft or patient survival at 1, 5, and 10 years. We observed a greater risk of urological complication in patients with PUV. RT with PUV constitutes a special group due to the compulsory young age and the need for careful and complex medicosurgical management; nevertheless, the results achieved were similar to those obtained in our general RT population. PMID:16491414

Mendizabal, Santiago; Zamora, Isabel; Serrano, Agustin; Sanahuja, Maria Jose; Roman, Ezena; Dominguez, Carlos; Ortega, Pedro; García Ibarra, Fernando

In the United States, intense hurricanes (category 3, 4, and 5 on the Saffir/Simpson scale) with winds greater than 50 m s -1 have caused more damage than any other natural disaster [Pielke and Pielke, 1997]. Accurate estimates of wind speed exceedance probabilities (WSEP) due to intense hurricanes are therefore of great interest to (re)insurers, emergency planners, government officials, and populations in vulnerable coastal areas.The historical record of U.S. hurricane landfall is relatively complete only from about 1900, and most model estimates of WSEP are derived from this record. During the 1899-1998 period, only two category-5 and 16 category-4 hurricanes made landfall in the United States. The historical record therefore provides only a limited sample of the most intense hurricanes.

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

The similarity among veridical event probabilities, subjective probabilities inferred from Ss' estimates of the event probabilities, and subjective probabilities inferred from choices among bets involving the same events was examined. In one condition, su...

We present an approach for the calculation of spin density distributions for molecules that require very large active spaces for a qualitatively correct description of their electronic structure. Our approach is based on the density-matrix renormalization group (DMRG) algorithm to calculate the spin density matrix elements as a basic quantity for the spatially resolved spin density distribution. The spin density matrix elements are directly determined from the second-quantized elementary operators optimized by the DMRG algorithm. As an analytic convergence criterion for the spin density distribution, we employ our recently developed sampling-reconstruction scheme [J. Chem. Phys.2011, 134, 224101] to build an accurate complete-active-space configuration-interaction (CASCI) wave function from the optimized matrix product states. The spin density matrix elements can then also be determined as an expectation value employing the reconstructed wave function expansion. Furthermore, the explicit reconstruction of a CASCI-type wave function provides insight into chemically interesting features of the molecule under study such as the distribution of ? and ? electrons in terms of Slater determinants, CI coefficients, and natural orbitals. The methodology is applied to an iron nitrosyl complex which we have identified as a challenging system for standard approaches [J. Chem. Theory Comput.2011, 7, 2740].

Dislocation of a total knee arthroplasty is a rare but serious complication. In previous literature, when dislocation does occur, it is usually in the posterior direction in cases with a posterior stabilized total knee arthroplasty due to cam jump. We report an unusual case of anterior dislocation of an 11-year-old posterior stabilized total knee arthroplasty in a 55-year-old woman with rheumatoid arthritis occurred after a slip. PMID:21641178

Lee, Su Chan; Jung, Kwang Am; Nam, Chang Hyun; Hwang, Seung Hyun; Lee, Won Jun; Park, Il Seok

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

An isolated posterior femoral cutaneous nerve lesion is rare. There have been seven reported cases to date. We report a 51-year-old male with pain in the posterolateral thigh, atypical from the classic anatomical description. Somatosensory evoked potentials were suggestive of a posterior femoral cutaneous nerve lesion. We describe our operative exposure and technique for decompression of the posterior femoral cutaneous nerve and include a comparative anatomical explanation for the unusual area of our patient's pain. PMID:12201406

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.

Five patients with acute posterior multifocal placoid pigment epitheliopathy (APMPPE) have been subject to a follow-up study. All the patients had bilateral lesions. The follow-up period ranged from 1 month to 8 years (mean 4 years). All had resumed their previous work, although two patients had severe visual loss in one eye (6/36). No recurrences were observed. Automatic perimetry of the central visual field revealed moderate central scotomata between 5 and 10 db, corresponding to derangement of the pigment epithelium. This may indicate that the pigment derangement may be caused by alterations in the pigment granules in the pigment epithelial cells, and that the pigment epithelial cells have recovered. There were absolute scotomata in two eyes corresponding to chorioretinal atrophy. PMID:3751514

A pathological study was performed on the necropsy eyes of a 59-year old-woman who had suffered for nine years from multifocal posterior uveitis. The disease had been controlled by steroid therapy with good preservation of visual function. Extensive investigation did not reveal the aetiology. On macroscopic examination numerous focal lesions with various degrees of pigmentation were observed scattered across the fundi. These lesions were studied by light and electron microscopy and immunohistochemistry. There was ongoing chorioretinal inflammation in the foci, producing destruction of Bruch's membrane, the retinal pigment epithelium (RPE), and the outer retina. The focal scars showed migration of RPE and glial cells and neovascularisation. Capillary and venule endothelial cells were swollen at the inflammatory sites. Attempts to establish a cause for this condition were unsuccessful. Images

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.

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

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

A number of recent studies have investigated posterior development in several different arthropods. As previously found in spiders, it has been discovered that Delta-Notch signaling is required for the development of posterior segments in an insect, the cockroach Periplaneta americana. Furthermore analysis of Wnt8 function in the spider Achaearanea tepidariorum and the beetle Tribolium castaneum demonstrates that this Wnt ligand is required for the establishment of the growth zone and development of posterior segments in both these arthropods. Taken together these studies provide an interesting insight into the architecture of the genetic network that regulated posterior development in the common ancestor of the arthropods.

A number of recent studies have investigated posterior development in several different arthropods. As previously found in spiders, it has been discovered that Delta-Notch signaling is required for the development of posterior segments in an insect, the cockroach Periplaneta americana. Furthermore analysis of Wnt8 function in the spider Achaearanea tepidariorum and the beetle Tribolium castaneum demonstrates that this Wnt ligand is required for the establishment of the growth zone and development of posterior segments in both these arthropods. Taken together these studies provide an interesting insight into the architecture of the genetic network that regulated posterior development in the common ancestor of the arthropods. PMID:19513274

We present an error-diagnostic validation method for posterior distributions in Bayesian signal inference, an advancement of a previous work. It transfers deviations from the correct posterior into characteristic deviations from a uniform distribution of a quantity constructed for this purpose. We show that this method is able to reveal and discriminate several kinds of numerical and approximation errors, as well as their impact on the posterior distribution. For this we present four typical analytical examples of posteriors with incorrect variance, skewness, position of the maximum, or normalization. We show further how this test can be applied to multidimensional signals.

Dorn, Sebastian; Oppermann, Niels; Enßlin, Torsten A.

Purpose To evaluate the effect of femoral condylar offset and posterior tibial slope on maximal flexion angle of the knee in posterior cruciate ligament (PCL)-sacrificing total knee arthroplasty (TKA, Medial-Pivot Knee System). Materials and Methods Forty-five knees in 35 patients who could be followed up more than 1 year after PCL-sacrificing TKA were evaluated retrospectively. We measured and analyzed the preoperative and postoperative maximal flexion angle, posterior femoral condylar offset difference, posterior femoral condylar offset ratio difference, and tibial slope. Results The mean maximal flexion angle after TKA was 118.44°±9.8° and significantly related to postoperative tibial slope (11.78°±6.2°) in correlation analysis (R=0.451, p=0.002). There was no statistical relationship between the postoperative maximal flexion angle and the posterior femoral condylar offset difference (3.24±3.862 mm, R=0.105, p=0.493) and posterior femoral condylar offset ratio difference (0.039±0.029 mm, R=-0.163, p=0.284). Conclusions The maximal flexion angle of the knee after PCL-sacrificing TKA was significantly related to the postoperative tibial slope. Therefore, posterior tibial slope can be considered as a factor that affects maximal flexion angle after PCL-sacrificing TKA.

The detailed behavior of many molecular processes in the cell, such as protein folding, protein complex assembly, and gene regulation, transcription and translation, can often be accurately captured by stochastic chemical kinetic models. We investigate a novel computational problem involving these models – that of finding the most-probable sequence of reactions that connects two or more states of the system observed at different times. We describe an efficient method for computing the probability of a given reaction sequence, but argue that computing most-probable reaction sequences is EXPSPACE-hard. We develop exact (exhaustive) and approximate algorithms for finding most-probable reaction sequences. We evaluate these methods on test problems relating to a recently-proposed stochastic model of folding of the Trp-cage peptide. Our results provide new computational tools for analyzing stochastic chemical models, and demonstrate their utility in illuminating the behavior of real-world systems.

Recent theoretical progress in nonequilibrium thermodynamics, linking thephysical principle of Maximum Entropy Production (“MEP”) to the information-theoretical“MaxEnt” principle of scientific inference, together with conjectures from theoreticalphysics that there may be no fundamental causal laws but only probabilities for physicalprocesses, and from evolutionary theory that biological systems expand “the adjacentpossible” as rapidly as possible, all lend credence to the proposition that probability shouldbe recognized as a fundamental physical motive. It is further proposed that spatial order andtemporal order are two aspects of the same thing, and that this is the essence of the secondlaw of thermodynamics.

Cell migration requires a defined cell polarity which is formed by diverse cytoskeletal components differentially localized to the poles of cells to extracellular signals. Rap-GAP3 transiently and rapidly translocates to the cell cortex in response to chemoattractant stimulation and localizes to the leading edge of migrating cells. Here, we examined localization of truncated RapGAP3 proteins and found that the I/LWEQ domain in the central region of RapGAP3 was sufficient for posterior localization in migrating cells, as opposed to leading-edge localization of full-length Rap-GAP3. All truncated proteins accumulated at the leading edge of migrating cells exhibited clear translocation to the cell cortex in response to stimulation, whereas proteins localized to the posterior in migrating cells displayed no translocation to the cortex. The I/LWEQ domain appears to passively accumulate at the posterior region in migrating cells due to exclusion from the extended front region in response to chemoattractant stimulation rather than actively being localized to the back of cells. Our results suggest that posterior localization of the I/LWEQ domain of RapGAP3 is likely related to F-actin, which has probably different properties compared to newly formed F-actin at the leading edge of migrating cells, at the lateral and posterior regions of the cell.

Background Tibialis posterior muscle weakness has been documented in subjects with Stage II posterior tibial tendon dysfunction (PTTD) but the effect of weakness on foot structure remains unclear. The association between strength and flatfoot kinematics may guide treatment such as the use of strengthening programs targeting the tibialis posterior muscle. Materials and Methods Thirty Stage II PTTD subjects (age; 58.1 ± 10.5 years, BMI 30.6 ± 5.4) and 15 matched controls (age; 56.5 ± 7.7 years, BMI 30.6 ± 3.6) volunteered for this study. Deep Posterior Compartment strength was measured from both legs of each subject and the strength ratio was used to compare each subject’s involved side to their uninvolved side. A 20% deficit was defined, a priori, to define two groups of subjects with PTTD. The strength ratio for each group averaged; 1.06 ± 0.1 (range 0.87 to 1.36) for controls, 1.06 ± 0.1 (range, 0.89 to 1.25), for the PTTD strong group, and 0.64 ± 0.2 (range 0.42 to 0.76) for the PTTD weak group. Across four phases of stance, kinematic measures of flatfoot were compared between the three groups using a two-way mixed effect ANOVA model repeated for each kinematic variable. Results Subjects with PTTD regardless of group demonstrated significantly greater hindfoot eversion compared to controls. Subjects with PTTD who were weak demonstrated greater hindfoot eversion compared to subjects with PTTD who were strong. For forefoot abduction and MLA angles the differences between groups depended on the phase of stance with significant differences between each group observed at the pre-swing phase of stance. Conclusion Strength was associated with the degree of flatfoot deformity observed during walking, however, flatfoot deformity may also occur without strength deficits.

Neville, Christopher; Flemister, Adolph S.; Houck, Jeff R.

This article examines some of the various judgmental errors and rationales that high school students make when attempting to solve basic probability exercises. Many of these errors allow the students to arrive at a correct answer and, thus, need to be examined more closely. (Contains 4 tables.)

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 m...

Several probability-possibility transformations are compared in terms of the closeness of preserving second-order properties. The comparison is based on experimental results obtained by computer simulation. Two second-order properties are involved in this study: noninteraction of two distributions and projections of a joint distribution.

THIS NOTE DESCRIBES THE PROCEDURES USED IN DETERMINING DYNAMOD II AGE TRANSITION MATRICES. A SEPARATE MATRIX FOR EACH SEX-RACE GROUP IS DEVELOPED. THESE MATRICES WILL BE USED AS AN AID IN ESTIMATING THE TRANSITION PROBABILITIES IN THE LARGER DYNAMOD II MATRIX RELATING AGE TO OCCUPATIONAL CATEGORIES. THREE STEPS WERE USED IN THE PROCEDURE--(1)…

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…

This paper presents a probability method for detecting people in a static image. We simplify people as a torso and four limbs. The torso is fitted by a quadrangle, and each limb is fitted by one or two quadrangles depending on its pose. In order to find people, we should try to find a combination of quadrangles that must satisfy

In this 21-minute video of a third grade class, the teacher, Carolyn Bereska, guides students through an exploration of probability terms utilizing a "walk-on number line". Along with the video, there are support materials: a math lesson plan and a professional development guide.

Posterior tibial tendon dysfunction is common and a major cause of flat foot (pes planus) and functional impairment in adults. It is frequently undiagnosed and therefore inappropriately managed. This review raises awareness of posterior tibial tendon dysfunction with the intention of improving patient management. PMID:22875521

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

The overall aim of this study is to compare the effectiveness of cervical lateral mass plate (CLMP) fixation to that of cervical lateral mass rod (CLMR) fixation and transpedicular fixation in providing stability to the cervical spine. Twenty-one cervical spines will be tested intact and with instrumentation in varying degrees of instability including posterior instability, anterior\\/posterior instability, corpectomy, and reconstructed

R. P. Morris; B. Svagr; R. M. Patterson; J. Yang; A. J. Muffoletto; J. W. Simmons

Summary The management of hydrocephalus secondary to a posterior fossa tumour is controversial. We audited recent practice with a retrospective analysis of 287 consecutive patients undergoing posterior fossa exploration for tumour. 85 shunts and 112 external ventricular drains (EVD) were placed. The overall CNS infection rate in the series was 6%. There was a significantly higher (p < 0.01) infection

Treatment of hydrocephalus in posterior fossa tumors in children is still a matter of controversy and different centers have their own routines. In this regard, hospital records of all children with posterior fossa tumors treated in our center during the interval of 1985-1995 were reviewed. Patients' demographic and diagnostic data were analyzed and the frequencies of shunting procedures were determined.

S. M. Abdollahzadeh-Hosseini; H. Rezaishiraz; F. Allahdini

BACKGROUNDWe report the clinical, radiological, and surgical findings of patients with posterior fossa meningiomas surgically treated at our institution over the last 6 years.METHODSWe reviewed 161 consecutive cases of posterior fossa meningiomas operated on between April 1993 and April 1999 at The George Washington University Medical Center.RESULTSThere were 128 female and 33 male patients (mean age 47 years, range of

Fabio Roberti; Laligam N Sekhar; Chandrasekar Kalavakonda; Donald C Wright

Neurological complications have rarely been described after blood transfusion. Posterior reversible encephalopathy syndrome (PRES) is a recently recognized entity affecting predominantly the posterior cerebral hemispheres. We report two distinctive cases with history of chronic anemia that developed headache, blurred vision and seizure after blood transfusion. Magnetic resonance imaging indicated vasogenic edema consistent with PRES. PMID:24857623

The sciatic nerve is by far the most common nerve accidentally injured during intramuscular injection. Despite its close proximity to the sciatic nerve, however, injury to the posterior femoral cutaneous nerve is apparently quite rare. In this report, clinical features of a patient with isolated injection injury to the posterior femoral cutaneous nerve are described. PMID:2586740

It is now widely accepted that the goal of deterministic earthquake prediction is unattainable in the short term and may even be forbidden by nonlinearity in the generating dynamics. This nonlinearity does not, however, preclude the estimation of earthquake probability and, in particular, how this probability might change in space and time; earthquake hazard estimation might be possible in the absence of earthquake prediction. Recently, there has been a major development in the understanding of stress triggering of earthquakes which allows accurate calculation of the spatial variation of aftershock probability following any large earthquake. Over the past few years this Coulomb stress technique (CST) has been the subject of intensive study in the geophysics literature and has been extremely successful in explaining the spatial distribution of aftershocks following several major earthquakes. The power of current micro-computers, the great number of local, telemeter seismic networks, the rapid acquisition of data from satellites coupled with the speed of modern telecommunications and data transfer all mean that it may be possible that these new techniques could be applied in a forward sense. In other words, it is theoretically possible today to make predictions of the likely spatial distribution of aftershocks in near-real-time following a large earthquake. Approximate versions of such predictions could be available within, say, 0.1 days after the mainshock and might be continually refined and updated over the next 100 days. The European Commission has recently provided funding for a project to assess the extent to which it is currently possible to move CST predictions into a practically useful time frame so that low-confidence estimates of aftershock probability might be made within a few hours of an event and improved in near-real-time, as data of better quality become available over the following day to tens of days. Specifically, the project aim is to assess the extent to which this is scientifically feasible in terms of our understanding of the physical phenomena which control the variation of seismicity following a large event due to stress redistribution and practically possible given present limitations on data availability, data quality and computational or data transfer speeds. The project is divided into a number of elements designed to reflect the temporal sequence of tasks that must be undertaken for the prediction of aftershock hazard. These tasks include determining a time-indexed sequence of slip distributions for both real and synthetic events, calculating a suite of time-indexed stress perturbations and quantitatively comprising predicted and observed aftershock distributions, and developing techniques for predicting likely strong ground motion from the predicted spatial distribution of aftershocks.

Arachnoid cysts are benign cysts occurring in the intra-arachnoid space and containing cerebrospinal fluid. They constitute approximately 1 per cent of all intracranial masses. They are uncommon in the posterior cranial fossa. Common presenting symptoms include headaches, seizures, focal neurologic signs and vague dizziness. Magnetic resonance imaging is the preferred method of investigation, and the treatment for symptomatic cysts is generally surgical drainage. We report the unusual presentation of a young patient with a posterior fossa arachnoid cyst that manifested in the form of isolated unilateral sensorineural hearing loss. The patient underwent posterior fossa craniotomy and marsupialization of the cyst. To our knowledge, posterior fossa arachnoid cyst presenting with isolated hearing loss alone has not been reported in the English literature. A review of the literature pertaining to posterior fossa arachnoid cysts, including the clinical features, diagnosis and management, is also presented. PMID:16848918

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.

Thirty-five consecutive patients with unilateral posterior dislocation of the hip were studied for complications at an average follow-up of 4.6 years (range 2–10 years). Thompson–Epstein type IV dislocation was most frequent (10/35), reflecting an increase in high-speed motor vehicles in the developing countries. It is also a severe injury that leads to a maximum number of complications, which include avascular necrosis, osteoarthosis, sciatic nerve injury and heterotrophic ossification. Avascular necrosis and osteoarthritis of the hip were observed maximally in type IV patients, even when reduction was achieved in less than twelve hours and may reflect the severity of initial injury. Heterotrophic ossification was observed in five of the ten patients with type IV dislocation and was associated with multiple attempts at reduction. Sciatic nerve injury did not recover completely in all cases, especially when reduction was delayed over twelve hours. Observing that the greatest numbers of complications were seen among patients with type IV dislocations, it may be prudent to warn such individuals about the likely prognosis at the outset, especially in today’s world when the demands and expectations are high.

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.

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

Emergent and resurgent arthropod vector-borne diseases are major causes of systemic morbidity and death and expanding worldwide. Among them, viral and bacterial agents including West Nile virus, Dengue fever, Chikungunya, Rift Valley fever, and rickettsioses have been recently associated with an array of ocular manifestations. These include anterior uveitis, retinitis, chorioretinitis, retinal vasculitis and optic nerve involvement. Proper clinical diagnosis of any of these infectious diseases is based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. The diagnosis is usually confirmed by the detection of a specific antibody in serum. Ocular involvement associated with emergent infections usually has a self-limited course, but it can result in persistent visual impairment. There is currently no proven specific treatment for arboviral diseases, and therapy is mostly supportive. Vaccination for humans against these viruses is still in the research phase. Doxycycline is the treatment of choice for rickettsial diseases. Prevention, including public measures to reduce the number of mosquitoes and personal protection, remains the mainstay for arthropod vector disease control. Influenza A (H1N1) virus was responsible for a pandemic human influenza in 2009, and was recently associated with various posterior segment changes. PMID:23258387

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

A 62-year-old female patient with metastatic renal cell carcinoma under third-line treatment with pazopanib for 8 weeks suddenly developed severe headaches, grand mal seizures and paresis of the left arm in combination with gait instability as well as nausea and vomiting during her vacation abroad. The emergency physician measured systolic blood pressure values over 300 mm Hg and suspected a stroke. The CT imaging without contrast agent in a local hospital did not show any pathologic findings despite bone metastases. The colleagues suspected cerebral metastases or meningeosis carcinomatosa and referred the patient to our department for further diagnostics and treatment planning. An MRI scan ruled out the suspected cerebral metastases or meningeosis carcinomatosa, but showed signs of reversible posterior leukoencephalopathy syndrome (RPLS) in the form of band-like hyperintensities as a sign of cytotoxic edema in the gray and white matter of the left parietal lobe. The patient then reported that similar blood pressure values had been measured shortly after the start of a first-line therapy with sunitinib, so that we discontinued the current treatment with pazopanib. Within 6 days the neurologic symptoms vanished and the patient was discharged. An intermittent hypertension persisted. A follow-up MRI 3 weeks later showed an RPLS-typical cortical infarction in the affected area. RPLS should be considered as the actual reason for neurologic findings in hypertensive patients with known metastatic cancers under tyrosine kinase inhibitor therapy. PMID:23626562

A 48-year-old man presented with visual dimness in the right eye that had developed 2 weeks previously. Dilated fundus examination showed few vitreous cells and numerous yellow, placoid lesions in both eyes. His right eye had more severe serous retinal detachment involving the macula. Fluorescein angiography demonstrated early irregular hypofluorescence with late staining in the areas of the yellow placoid lesions. He started a regimen of 60 mg of oral prednisone daily. Two weeks later, a serologic fluorescent treponemal antigen absorption test was positive for Ig G and Ig M. He was referred to an infectious disease specialist for antibiotic therapy. A week later, he returned, having stayed on prednisone only and not having taken the internist's antibiotic prescription. Meanwhile, the chorioretinitis in his right eye, which had initially been at a more advanced stage, was resolved with the use of steroids. The chorioretinitis in his left eye, which was aggravated at an earlier stage, ultimately recovered. Our case had atypical courses such that one eye improved and the other worsened during the same steroid treatment period. This result was inconsistent with that of previous reports showing that oral steroid influences the clinical course of acute syphilitic posterior placoid chorioretinitis.

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.

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

We first define Algorithmic Probability, an extremely powerful method of inductive inference. We discuss its completeness,\\u000a incomputability, diversity and subjectivity and show that its incomputability in no way inhibits its use for practical prediction.\\u000a Applications to Bernoulli sequence prediction and grammar discovery are described. We conclude with a note on its employment\\u000a in a very strong AI system for very

To estimate lightning stroke overvoltages exactly, the occurrence probability of lightning stroke current waveforms must be accurately evaluated. This paper firstly formulated the occurrence probability distribution of lightning stroke current waveforms, taking into account the correlation between the current amplitude and the front duration. Next, lightning overvoltages were calculated, with the current amplitude and the front duration of lightning current

Calculating safety and reliability probabilities with functions of uncertain variables can yield incorrect or misleading results if some precautions are not taken. One important consideration is the application of constrained mathematics for calculating probabilities for functions that contain repeated variables. This paper includes a description of the problem and develops a methodology for obtaining an accurate solution.

...2010-10-01 2010-10-01 false Probability calculation. 1.1623 Section... General Procedures Â§ 1.1623 Probability calculation. (a) All calculations...less than three significant digits. Probabilities will be truncated to the number...

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

...2009-10-01 2009-10-01 false Probability calculation. 1.1623 Section... General Procedures Â§ 1.1623 Probability calculation. (a) All calculations...less than three significant digits. Probabilities will be truncated to the number...

A methodology for tornado hazard probability assessment is presented along with a discussion of the assumptions and rationale used in the procedure. Application of the method produces a tornado hazard probability model, which gives the probabilities of an...

The problem of dynamically estimating a time-varying set of targets can be cast as a filtering problem using the random finite set (or point process) framework. The probability hypothesis density (PHD) filter is a recursion that propagates the posterior intensity function-a 1st-order moment-of the random set of multiple targets in time. Like the Bayesian single-target filter, the PHD recursion also

We examined patients affected by a posterior wall fracture of the acetabulum treated with a minimally invasive posterior approach (from 12 to 18 cm). During 2004-2006 19 patients were treated by this approach. 4 patients had a combined surgery by the ileo-inguinal approach. Fracture fixation was performed using reconstruction plates and screws. All the patients were studied with typical X-rays projection for pelvis and iliac oblique view and obturator oblique view (Judet view) and CT scan with 3D reconstruction. After 3 months a CT scan was performed on about 30% of our patients, which demonstrated the perfect healing of the fractures. The most important advantages we observed using this approach were a lesser split of the gluteus maximus and no risk of damage for the superior gluteal nerve. In the early post-operative rehabilitation we examined the trophism of the gluteus maximus, which was found to be better than in patients treated with the typical Kocher-Langenbeck approach. The only absolute contraindication for this technique is in obese patients. The post-operative complications include one case of heterotypic ossification of the gluteus minimus and one case of peroneal-nerve palsy with the spontaneous and complete recovery within 6 months. According to our experience this kind of approach could be used for posterior wall fracture of the pelvis and it can be extended to transverse fractures. In the post-operative period the greatest advantage is the lesser muscle damage and therefore a most effective rehabilitation. PMID:19711156

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 posteriorprobability 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 posteriorprobability distribution of surface rain rate.

Posterior urethral valves represent the most common cause of bladder outlet obstruction in infancy that impairs renal and bladder function. Long-term outcome of patients with previous PUV is evaluated. Patients over 18 years of age, treated from 1982 to 1995 before the age of 3 years were considered. Previous surgery, renal function, bladder activity, urinary incontinence, and fertility/sexual activity were evaluated. Clinical interview, creatinine clearance, uroflowmetry with ultrasound post-void urine residue, and self-administered questionnaire were recorded. Out of 45 identified records, 24 patients (53.3%) accepted to be enrolled (age 18-34 years, mean 23 years). The mean follow-up was 19.5 years (16-30 years). Out of the 21 excluded patients, 20 did not reply to the clinical interview and 1 died at age of 6 years. All the 24 patients had early endoscopic section of PUV; nine also received transient ureterocutaneostomy or vesicostomy. Ureteroneocystostomy was performed in five patients and ureterocystoplasty with unilateral nephrectomy in two. At follow-up chronic renal failure was detected in 13 patients (54.1%) and 9 (37.5%) had arterial hypertension. End-stage renal disease developed in five patients (20.8%): three had successful renal transplantation and two were in dialysis. Lower urinary tract symptoms were present in seven patients (29.1%). No significant fertility deficit and sexual dysfunction were observed in 23 patients, while 1 patient was azoospermic. No paternity was reported so far. Long-term outcome of patients with previously treated PUV is mandatory. Kidney, bladder, and sexual functions should be monitored till adulthood to verify any modified behaviour. PMID:21748651

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

Background In posterior cortical atrophy (PCA), there is a progressive impairment of high-level visual functions and parietal damage, which might predict the occurrence of visual neglect. However, neglect may pass undetected if not assessed with specific tests, and might therefore be underestimated in PCA. In this prospective study, we aimed at establishing the side, the frequency and the severity of visual neglect, visual extinction, and primary visual field defects in an unselected sample of PCA patients. Methods Twenty-four right-handed PCA patients underwent a standardized battery of neglect tests. Visual fields were examined clinically by the confrontation method. Results Sixteen of the 24 patients (66%) had signs of visual neglect on at least one test, and fourteen (58%) also had visual extinction or hemianopia. Five patients (21%) had neither neglect nor visual field defects. As expected, left-sided neglect was more severe than right-sided neglect. However, right-sided neglect resulted more frequently in this population (29%) than in previous studies on focal brain lesions. Conclusion When assessed with specific visuospatial tests, visual neglect is frequent in patients with PCA. Diagnosis of neglect is important because of its negative impact on daily activities. Clinicians should consider the routine use of neglect tests to screen patients with high-level visual deficits. The relatively high frequency of right-sided neglect in neurodegenerative patients supports the hypothesis that bilateral brain damage is necessary for right-sided neglect signs to occur, perhaps because of the presence in the right hemisphere of crucial structures whose damage contributes to neglect.

In a period of ten years, since January 1996, we have encountered seven cases of posterior cerebral artery aneurysms (0.58% of surgically treated 1027 aneurysms in our hospital). Six of these cases were females (from 39 years old to 73 years old, average 54.5 years old). In five of the cases, neck clippings were performed, using the pterional approach for one P1 and one P2a aneurysm, the remaining three were clipping using the subtemporal approach for one P2a and two P2p aneurysms. In one case diagnosed as "unknown SAH" by typical findings of the CT scan and normal four-vessel study at the time of admission. The second vertebral angiography (two weeks later) revealed a P2a aneurysm. Such a case attracted our interest in the clinic, because many similar cases might have been diagnosed as "unknown SAH". In the case of a 42-year-old male with intracerebral hematoma, four-vessel study made a definite diagnosis as moyamoya disease and revealed a P2a aneurysm, which we cured by embolization of GDC for the preservation of anastomosis networks which had already been formed. Intravascular embolization is very effective, but sufficient studies are required before applying it in the cases of large and/or thrombosed aneurysms. We described surgical approaches about pterional, subtemporal and transchoroidal approaches and discussed some of the differences in the classification methods of Pia, Yasargil, Zear & Rhoton and Seoane. In particular, attention is necessary because we have confused Yasargil's classification with Zeal & Rhoton's classifications by using of the same notation, "Pn". PMID:17424966

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.

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

In addition to computing the posterior distributions for hidden variables in Bayesian networks, one other important inference task is to find the most probable explanation (MPE). MPE provides the most likely configurations to explain away the evidence and helps to manage hypotheses for decision making. In recent years, researchers have proposed a few methods to find the MPE for discrete Bayesian networks. However, finding the MPE for hybrid networks remains challenging. In this paper, we first briefy review the current state-of-the-art in the literature regarding various explanation methods. We then present an algorithm by using a modified max-product clique tree to find the MPE for accommodating the needs in hybrid Bayesian networks. A detailed example is demonstrated to show the algorithm.

Several findings from both human neuroimaging and nonhuman primate studies suggest that the posterior medial orbitofrontal cortex (OFC) may be critical for the motivational control of goal-directed behavior. The present study was conducted to clarify the role of the left and right posterior medial OFC in that function by examining the effects of focal unilateral lesions to this region on the performance on an incentive working memory task. The study covered patients who had undergone surgery for an ACoA aneurysm and normal control subjects (C). The patients were subdivided into three groups: those with resection of the left (LGR+) or right (RGR+) posterior part of the gyrus rectus, and without such a resection (GR-). Participants performed a 2-back working memory task under three motivational conditions (penalty, reward, and no-incentive). The C group performed worse in the penalty condition and better in the reward condition as compared to the no-incentive condition. Similar results were obtained for the GR- group. Performance of the LGR+ group did not depend on incentive manipulations, whereas the RGR+ group performed better in both the penalty and reward conditions than in the no-incentive condition. The results show that the posterior medial OFC is involved in the motivational modulation of working memory performance. Our findings also suggest that the left posterior medial OFC plays a crucial role in this function, whereas the right posterior medial OFC is particularly involved in the processing of the punishing aspect of salient events and it probably mediates in guiding behavior on the basis of negative outcomes of action. PMID:21741492

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.

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

True posterior communicating artery aneurysms originate exclusively from the wall of this artery and should be differentiated from aneurysms of the posterior communicating segment of the distal carotid artery. As these lesions are rare, their anatomical relationships have been poorly described; likewise, reports concerning their endovascular treatment are extremely rare and the technical aspects poorly detailed. A case of a patient with a true aneurysm of the left posterior communicating artery treated by endovascular coiling is presented. A literature review was also conducted to illustrate the anatomical and technical details relevant to achieving its successful treatment. PMID:23831341

Almeida-Pérez, Rafael; Espinosa-García, Héctor; Alcalá-Cerra, Gabriel; de la Rosa-Manjarréz, Ginna; Orozco-Gómez, Fernando

Arachnoid cysts constitute 1% of all intracranial space-occupying lesions. In the posterior fossa, they typically produce vague, nonspecific symptoms. However, a subset of these lesions can produce signs and symptoms indistinguishable from those of Meniere's disease. We discuss the clinical and laboratory features of 2 cases of posterior fossa arachnoid cysts mimicking Meniere's disease as well as the substantial resolution of symptoms in 1 patient after cysto-peritoneal shunt. Posterior fossa arachnoid cyst must be considered in the differential diagnosis of patients presenting with signs and symptoms of Meniere's disease. PMID:14608578

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

Here we report a case of pseudoaneurysm of distal posterior tibial artery following closed fracture of calcaneous. Association of pseudoaneurysm of posterior tibial artery with fracture of calcaneous is extremely uncommon. It is always suggested that pseudoaneurysm be treated by reconstruction, but here we present the case treated by ligation, obliteration and excision as it was situated distally and the plantar arch circulation was maintained. The purpose of this case report is to bring attention to this complication of vascular trauma, which may cause delayed symptoms long time after the injury as well as the rare incidence of posterior tibial artery involvement with fracture calcaneous. PMID:23133058

Asystole during posterior fossa neurosurgical procedures is not uncommon. Various causes have been implicated, especially when surgical manipulation is carried out in the vicinity of the brain stem. The trigemino-cardiac reflex has been attributed as one of the causes. Here, we report two cases who suffered asystole during the resection of posterior fossa tumors. The vago-glossopharyngeal reflex and the direct stimulation of the brainstem were hypothesized as the causes of asytole. These episodes resolved spontaneously following withdrawal of the surgical stimulus emphasizing the importance of anticipation and vigilance during critical moments of tumor dissection during posterior fossa surgery. PMID:22870159

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

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

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

...2012-04-01 false Posterior artificial tooth with a metal insert. 872.3900 ...Â§ 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is a...

Probability and risk are important factors for value-based decision making and optimal foraging. In order to survive in an unpredictable world, organisms must be able to assess the probability and risk attached to future events and use this information to generate adaptive behavior. Recent studies in non-human primates and rats have shown that both probability and risk are processed in a distributed fashion throughout the brain at the level of single neurons. Reward probability has mainly been shown to be coded by phasic increases and decreases in firing rates in neurons in the basal ganglia, midbrain, parietal, and frontal cortex. Reward variance is represented in orbitofrontal and posterior cingulate cortex and through a sustained response of dopaminergic midbrain neurons.

This report concerns 35 adult patients with lumbar or sciatic pain and axial CT findings reportedly associated with posterior apophyseal ring fractures. Review of the CT images suggested two pathophysiologic categories. (1) Posterior Schmorl--A posterior intravertebral disc herniation with posterior displacement of a fractured or remodelled vertebral margin. (2) Calcified subligamentous--Reactive annular and or posterior longitudinal ligament calcification at the periphery of a herniated disc with or without remodelling and anterior displacement of the posterior vertebral margin. PMID:1749472

This article and its sequel outline recent developments in the theory of infinite divisibility and Lévy processes in free probability, a subject area belonging to noncommutative (or quantum) probability. The present paper discusses the classes of infinitely divisible probability measures in classical and free probability, respectively, via a study of the Bercovici–Pata bijection between these classes.

Recent studies have demonstrated subadditivity of human probability judgment: The judged probabilities for an event partition sum to more than 1. We report conditions under which people's probability judgments are superadditive instead: The component judgments for a partition sum to less than 1. Both directions of deviation from additivity are interpreted in a common framework, in which probability judgments are

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

Visual loss caused by posterior dislocation of an intraocular lens (IOL) may be managed by placement of a secondary IOL without removal of the dislocated IOL. However, the improved visual acuity may lead to visual disturbances from the mobile, dislocated IOL. Removal of dislocated implants through the pars plana entails risks of a large pars plana incision to include hemorrhage, hypotony, and a greater potential for vitreous traction caused by extraction across the vitreous base. Removal via the corneal limbus lessens these risks but is made more difficult in the presence of a coexisting posterior chamber IOL. The technique reported allows a controlled conversion from posterior to anterior segment surgical techniques that may aid in either the removal or repositioning of posteriorly dislocated lens implants. PMID:11176991

Twenty-eight eyes were followed for at least 6 months after phacoemulsification, posterior capsulorhexis and intracapsular lensimplantation. No case of clinical significant macular edema, retinal tear or retinal detachment was noted during this period. PMID:7493119

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

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

We report a 16-year-old boy who presented with high cervical cord compression caused by a midline posterior fossa arachnoid cyst lying below the vermis. Cystoperitoneal shunting resulted in a dramatic improvement of neurological signs. PMID:11013694

A case of bifrontal epidural haematoma secondary to ventriculocardiac (Spitz-Holter) shunt operation and posterior fossa exploration is reported. The relevant literature has been reviewed. The diagnosis of this complication was made by CT scan.

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.

The afferent and efferent vessels as well as the choriocapillaris in the human posterior pole, studied in flat preparations, paraffin sections, and Epon sections, formed relatively discrete units of organization which are called lobules. A lobule is a seg...

Purpose The purpose of this study was to describe the clinical finding of macular subretinal fluid by optical coherence tomography in patients with acute posterior multifocal placoid pigment epitheliopathy. Methods Patients with acute posterior multifocal placoid pigment epitheliopathy were identified, and those with macular serous retinal detachment noted clinically and confirmed by optical coherence tomography are described. Results Of 8 patients with acute posterior multifocal placoid pigment epitheliopathy evaluated by the uveitis service at the Illinois Eye and Ear Infirmary between 2003 and 2008, 4 eyes of 3 patients presented with macular subretinal fluid. Confirmatory optical coherence tomography was performed in two patients. Conclusion Acute posterior multifocal placoid pigment epitheliopathy may present clinically with macular subretinal fluid. This finding can be confirmed and monitored with optical coherence tomography.

BIRNBAUM, ANDREA D.; BLAIR, MICHAEL P.; TESSLER, HOWARD H.; GOLDSTEIN, DEBRA A.

We report on a patient with acute posterior multifocal placoid pigment epitheliopathy and sarcoidosis. A review of the literature suggests that sarcoidosis may occur more commonly in this condition than previously suspected. Images

Dick, D J; Newman, P K; Richardson, J; Wilkinson, R; Morley, A R

Traumatic posterior locked shoulder dislocation is very rare. The dislocation is often combined with fractures of the humeral head or reversed Hill-Sachs deformities. This case report shows two different possibilities for treatment. PMID:18305918

A complete posterior interosseous nerve palsy resulted from axonotmesis caused by pressure from a ganglion cyst. Excision of the neuroma and interpositional nerve grafting gave a most satisfactory outcome. PMID:2269847

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.

Post-hysterectomy vault prolapse may be accompanied by anterior (cystocele) and posterior (rectocele) pelvic compartment prolapse. We describe our results with sacrocolpopexy with anterior and posterior polytetrafluoroethylene mesh (SCAPM) extensions. A prospective on-going study is presented of 12 consecutive, complicated patients referred to our tertiary referral unit with a median age of 60 years (range 39–69) who underwent SCAPM between April

The case of a patient with a venous angioma located in the midline of the posterior fossa and responsible for a cerebellar hemorrhage is reported. The patient had a good recovery after removal of the hematoma. We reviewed this and seven other cases of venous angioma in the posterior fossa reported in the literature. It appears that those venous angiomas that occur in the cerebellar hemisphere and produce a cerebellar hematoma can be successfully removed. PMID:3961660

Reported here is a 19-year-old female patient with familial Mediterranean fever who was seen for altered mental status and seizures. She was eventually diagnosed to have posterior reversible leukoencephalopathy syndrome. Although a variety of conditions have been reported in association with this syndrome, to our best notice, this is the second case in whom familial Mediterranean fever and posterior reversible leukoencephalopathy coexists. PMID:20306050

We report on two patients with rare major intratumoral hemorrhage following ventriculoperitoneal shunt in posterior fossa tumors. A 28-year-old woman with a midline posterior fossa lesion, whose imaging features suggested a fourth ventricular ependymoma with obstructive hydrocephalus, was subjected to a right ventriculoperitoneal shunt. Her consciousness deteriorated, and she experienced massive intratumoral hemorrhage and later died. An eight-year-old girl presented

R. Santhanam; Anandh Balasubramaniam; B. A. Chandramouli

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.

A case of acute encephalopathy with posterior corticosubcortical vasogenic edema on magnetic resonance imaging is reported. Angiography showed cerebral arterial vasospasm. A diagnosis of acute post-streptococcal glomerulonephritis was made 2 days after admission. This report highlights the fact that acute post-streptococcal glomerulonephritis can be revealed by a posterior reversible encephalopathy syndrome and that cerebral vasospasm can concur with vasogenic edema in this condition. PMID:16901429

Aeby, Alec; David, Philippe; Fricx, Christophe; Jissendi, Patrice; Blecic, Serge; Van Bogaert, Patrick

A case is described of acute posterior multifocal placoid pigment epitheliopathy (APMPPE) in which one eye shows the typical active disease process while the other shows evidence of extensive degenerative changes of the posterior pole with disturbance of the pigment epithelium. It is postulated the case presented shows that APMPPE may not be as benign a condition as previously thought, and that it may recur after a period of years. PMID:299132

There have been several reports on hemivertebra resection via a posterior-only procedure. However, the number of reported\\u000a cases is small, and various types of instrumentation have been used. In our study, we retrospectively investigated 56 consecutive\\u000a cases of congenital scoliosis that were treated by posterior hemivertebra resection with transpedicular instrumentation. Radiographs\\u000a were reviewed to determine the type and location of

Jianguo Zhang; Wang Shengru; Guixing Qiu; Bin Yu; Wang Yipeng; Keith D. K. Luk

Some neutrons are emitted from fission fragments several seconds to several minutes after fission occurs. These delayed neutrons play a key role for the conduct and in safety aspects of nuclear reactors [1]. But the probabilities to emit such neutrons (Pn) are not well known. A summary of different database and compilation of Pn values is presented to show these discrepancies and uncertainties. Experiments are carried out at the Lohengrin mass spectrometer (at Institut Laue Langevin in Grenoble) and at the ISOLDE facility (CERN) in order to measure some Pn values. Two different techniques are used: either by using gamma-rays detection or neutron emission detection. These two techniques and some preliminary results are presented.

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 posteriorprobabilities for the Lagrange multipliers, and, finally, one can put error bars on the resulting estimated density function.

Background The comprehension of the gene regulatory code in eukaryotes is one of the major challenges of systems biology, and is a requirement for the development of novel therapeutic strategies for multifactorial diseases. Its bi-fold degeneration precludes brute force and statistical approaches based on the genomic sequence alone. Rather, recursive integration of systematic, whole-genome experimental data with advanced statistical regulatory sequence predictions needs to be developed. Such experimental approaches as well as the prediction tools are only starting to become available and increasing numbers of genome sequences and empirical sequence annotations are under continual discovery-driven change. Furthermore, given the complexity of the question, a decade(s) long multi-laboratory effort needs to be envisioned. These constraints need to be considered in the creation of a framework that can pave a road to successful comprehension of the gene regulatory code. Results We introduce here a concept for such a framework, based entirely on systematic annotation in terms of probability profiles of genomic sequence using any type of relevant experimental and theoretical information and subsequent cross-correlation analysis in hypothesis-driven model building and testing. Conclusion Probability landscapes, which include as reference set the probabilistic representation of the genomic sequence, can be used efficiently to discover and analyze correlations amongst initially heterogeneous and un-relatable descriptions and genome-wide measurements. Furthermore, this structure is usable as a support for automatically generating and testing hypotheses for alternative gene regulatory grammars and the evaluation of those through statistical analysis of the high-dimensional correlations between genomic sequence, sequence annotations, and experimental data. Finally, this structure provides a concrete and tangible basis for attempting to formulate a mathematical description of gene regulation in eukaryotes on a genome-wide scale.

For accurate superior or posterior repositioning of the maxilla in Le Fort I osteotomy, bone removal around the descending palatine artery (DPA) and maxillary tuberosity is required. Because the most common site of hemorrhage in the Le Fort I osteotomy is the posterior maxilla, this bone removal provides surgeons to surgical frustration of DPA injury. When the DPA is injured during the bone removal and the ligation is performed, aseptic necrosis of the maxilla may occur. Therefore, we report the use of a simple handmade retractor to protect the DPA in Le Fort I osteotomy. PMID:23714926

Accurate class probability estimation is important for medical decision making but is challenging, particularly when the number of candidate features exceeds the number of cases. Special methods have been developed for nonprobabilistic classification, but relatively little attention has been given to class probability estimation with numerous candidate variables. In this paper, we investigate overfitting in the development of regularized class probability estimators. We investigate the relation between overfitting and accurate class probability estimation in terms of mean square error. Using simulation studies based on real datasets, we found that some degree of overfitting can be desirable for reducing mean square error. We also introduce a mean square error decomposition for class probability estimation that helps clarify the relationship between overfitting and prediction accuracy. PMID:24338793

In cruciate-retaining (CR) type TKA, the increase in posterior condylar offset (PCO) is considered to be correlated to flexion\\u000a angle acquired postoperatively according to the article reported by Bellemans (J Bone Joint Surg Br 84:50–53, 2002). However,\\u000a the significance of PCO seems to differ according to the size of joints. We therefore have defined a new parameter of posterior\\u000a condylar

Study Design Retrospective study. Purpose To determine if posterior surgery alone can satisfactorily treat post-traumatic kyphosis (PTK). Overview of Literature One of the worst complications of vertebral fractures is PTK. The type of surgery and approach to treat a symptomatic and refractory PTK is a challenging issue in spinal surgery, and yet, there is no specific treatment algorithm. Methods From August 2003 to September 2010, we collected 26 cases (male to female ratio, 2.25; mean age, 31.9±9.7 years and follow-up period of 42.4±8.1 months) with PTK treated by posterior column osteotomy, spondylodesis, instrumentation and cement vertebroplasty in one stage posterior surgery. PTK angle, Oswestry Disability Index (ODI), visual analogue scale (VAS), and subjective satisfaction from surgery were used to determine the results. We used a student t test for analyzing the data before and after surgery. Results In our patients, T11 and L1 had the highest incidence of vertebral fractures. The results indicated that in PTK, ODI, and VAS were significantly improved this surgery. Solid fusion occurred in 96.2% of patients with 3.2°±2.1° loss of correction. A total of 84.6% of patients have satisfaction level of excellent and good. Conclusions Posterior surgery alone with posterior column osteotomy, vertebroplasty, posterior spinal fusion and instrumentation can effectively treat symptomatic PTK.

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

Kotil, Kad?r; Koksal, Neslihan sutpideler; Kayac?, Selim

Spondylolisthesis is a heterogeneous disorder characterized by subluxation of a vertebral body over another in the sagittal plane. Its most common form is isthmic spondylolisthesis (IS). This study aims to compare clinical outcomes of posterolateral fusion (PLF) with posterior lumbar interbody fusion (PLIF) with posterior instrumentation in the treatment of IS. We performed a randomized prospective study in which 80 patients out of a total of 85 patients with IS were randomly allocated to one of two groups: PLF with posterior instrumentation (group I) or PLIF with posterior instrumentation (group II). Posterior decompression was performed in the patients. The Oswestry low back pain disability (OLBP) scale and Visual Analogue Scale (VAS) were used to evaluate the quality of life (QoL) and pain, respectively. Fisher's exact test was used to evaluate fusion rate and the Mann-Whitney U test was used to compare categorical data. Fusion in group II was significantly better than in group I (p=0.012). Improvement in low back pain was statistically more significant in group I (p=0.001). The incidence of neurogenic claudication was significantly lower in group I than in group II (p=0.004). In group I, there was no significant correlation between slip Meyerding grade and disc space height, radicular pain, and low back pain. There was no significant difference in post-operative complications at 1-year follow-up. Our data showed that PLF with posterior instrumentation provides better clinical outcomes and more improvement in low back pain compared to PLIF with posterior instrumentation despite the low fusion rate. PMID:22260338

Farrokhi, Majid Reza; Rahmanian, Abdolkarim; Masoudi, Mohammad Sadegh

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.

The ability of classification systems to adjust their performance (sensitivity/specificity) is essential for tasks in which certain errors are more significant than others. For example, mislabeling cancerous lesions as benign is typically more detrimental than mislabeling benign lesions as cancerous. Unfortunately, methods for modifying the performance of Markov random field (MRF) based classifiers are noticeably absent from the literature, and thus most such systems restrict their performance to a single, static operating point (a paired sensitivity/specificity). To address this deficiency we present weighted maximum posterior marginals (WMPM) estimation, an extension of maximum posterior marginals (MPM) estimation. Whereas the MPM cost function penalizes each error equally, the WMPM cost function allows misclassifications associated with certain classes to be weighted more heavily than others. This creates a preference for specific classes, and consequently a means for adjusting classifier performance. Realizing WMPM estimation (like MPM estimation) requires estimates of the posterior marginal distributions. The most prevalent means for estimating these--proposed by Marroquin--utilizes a Markov chain Monte Carlo (MCMC) method. Though Marroquin's method (M-MCMC) yields estimates that are sufficiently accurate for MPM estimation, they are inadequate for WMPM. To more accurately estimate the posterior marginals we present an equally simple, but more effective extension of the MCMC method (E-MCMC). Assuming an identical number of iterations, E-MCMC as compared to M-MCMC yields estimates with higher fidelity, thereby 1) allowing a far greater number and diversity of operating points and 2) improving overall classifier performance. To illustrate the utility of WMPM and compare the efficacies of M-MCMC and E-MCMC, we integrate them into our MRF-based classification system for detecting cancerous glands in (whole-mount or quarter) histological sections of the prostate. PMID:21335309

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

The origin and course of the posterior femoral cutaneous nerve were observed macroscopically in 38 Japanese adult cadavers which were dissected in the University of Hokkaido, Faculty of Medicine during the years 1971/72 and the results obtained were compared with those from some other mammals (rat, rabbit, dog and cat) and a number of bibliographical findings on the other animals. On the basis of the archetype of the pudendal plexus, the site of origin of the posterior femoral cutaneous nerve was divided into seven portions as follows: the sciatic nerve or inferior gluteal nerve (I) and its originating roots (RI), the bigeminal nerve (B) and its originating roots (RB), the part of junction of I and B (CIB), the pudendal nerve (P) and its originating roots (RP). According to the arising mode, the posterior femoral cutaneous nerve was calssified into seven types: Type A (the sciatic nerve type); the nerve arises from I and RI (horse, rat, bird, frog and salamander). Type B (the sciatic transitional type); the nerve arises from I, RI, CIB, RB and B (MAN AND MONKEY). Type C (the bigeminal nerve type); the nerve arises from CIB, RB and B (gorilla, chimpanzee, orangutan, cat and sphenodon). Type D (the pudendal transitional type); the nerve arises from CIB, RB, B, RP and P (dog). Type E (the pudendal nerve type); the nerve arises from RP and P (pig, cattle and rabbit). Type F (the mixed type); a mixture of A to E types. These various patterns in the posterior femoral cutaneous nerve may be explained by the comparative anatomical explanation on the limb medial rotation given in Braus' text-book of Anatomy (Bd. I, S. 273). From these descriptions it is reasonable to presume that the main trunk of the posterior femoral cutaneous nerve of the tetrapod below the Aves arises from the sciatic nerve and is analogous to the gluteal branches of mammals, with its main stem still retained in the pudendal nerve. If the cutaneous area supplied by the posterior femoral cutaneous nerve expands to the lateral border of the buttock in company with the lower limb medial rotation, the part between this area and that supplied by the pudendal nerve is enlarged. At first, these expanded areas are probably supplied by the branches of the pudendal nerve, which gradually become independent to become the main stem of the posterior femoral cutaneous nerve in mammals. This nerve seems, therefore, to be primarily a division of the pedendal nerve, and so in man has various types of arising patterns, A to E, in accordance with the scheme in the phylogeny. Those hypothetical changes are observed in the human sacral plexus, from which the cutaneous nerve arises with a fan-shaped overlapping. PMID:1275304

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.)

We investigated the effects of probability on visual search. Previous work has shown that people can utilize spatial and sequential probability information to improve target detection. We hypothesized that performance improvements from probability information would extend to the efficiency of visual search. Our task was a simple visual search in which the target was always present among a field of distractors, and could take one of two colors. The absolute probability of the target being either color was 0.5; however, the conditional probability—the likelihood of a particular color given a particular combination of two cues—varied from 0.1 to 0.9. We found that participants searched more efficiently for high conditional probability targets and less efficiently for low conditional probability targets, but only when they were explicitly informed of the probability relationship between cues and target color.

Advances in medical therapies have greatly improved survivorship rates in children diagnosed with brain tumor; as a result, morbidities associated with survivorship have become increasingly important to identify and address. In general, pediatric posterior fossa tumor survivors tend to be less physically active than peers. This may be related to late effects of diagnosis and treatment, including cardiovascular, endocrine, psychological, and neurocognitive difficulties. Exercise has been shown to be effective in improving physical functioning, mood, and even cognitive functioning. Consequently, the benefits of physical exercise need to be explored and incorporated into the daily lives of pediatric posterior fossa tumor survivors. The primary aim of the present study was to establish the feasibility and safety of cardiorespiratory fitness testing in pediatric posterior fossa tumor survivors who had received cranial radiation therapy. Additionally, comparing our cohort to previously published data, we found that pediatric posterior fossa tumor survivors tended to be less fit than children with pulmonary disease as well as healthy controls, and approximately as fit as children with chronic heart disease and survivors of other types of childhood cancer. The importance of cardiorespiratory fitness in pediatric posterior fossa tumor survivors is discussed along with implications for future directions.

Wolfe, Kelly R.; Hunter, Gary R.; Madan-Swain, Avi; Reddy, Alyssa T.; Banos, James; Kana, Rajesh K.

Nasal resistance to airflow was measured by both anterior and posterior rhinomanometry in 15 healthy volunteers. It was found that the posterior method gave values on average 16% higher than the anterior method. This difference was statistically significant. We propose that this is due to posterior rhinomanometry measuring the resistance of the nasopharynx as well as the resistance of the nose. In the past a discrepancy between the 2 methods has been claimed to be due to an error in the standard form of the parallel resistance equation. This hypothesis was tested by measuring total nasal resistance by posterior rhinomanometry and comparing this with a total nasal resistance value derived from posterior rhinomanometric measurements of the resistance of the individual nasal cavities. The standard form of the parallel resistance formula was used to derive the total nasal resistance. There was no significant difference between the 2 values for total nasal resistance. We conclude that if measurements are made at the same pressure gradient then the use of this equation is valid. PMID:3581488

Jones, A S; Lancer, J M; Stevens, J C; Beckingham, E

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

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 V1 to V5 and slight ST-segment depression in leads I and aVL. There was ST-segment elevation in the posterior leads V7 to V9. 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 V7 to V9 leading to easier and faster recognition with consequences for treatment and improved prognosis. (Neth Heart J 2007;15:16-21.)

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

Isolated posterior femoral cutaneous nerve (PFCN) entrapment has only rarely been described in the literature and never documented electrophysiologically. We report an unusual occurrence of such an injury and use somatosensory evoked potentials (SSEP) to explore the extent of the lesion. A 40-year-old woman had localized numbness of the right posterior thigh after a left putamenal hemorrhage four years before this study. She made a complete recovery from her stroke within four months; however, she continued to experience decreased sensation in the right posterior thigh. Normal sural and peroneal nerve latencies, velocities, and amplitudes were obtained in the right leg. Electromyographic examination of right leg and related para spinal musculature was unremarkable. SSEP were then performed with CZ'-FZ (10-20 system) electrode placement. Normal sural, lateral femoral cutaneous, and posterior tibial responses were obtained bilaterally. Response differences consistent with an isolated right PFCN neuropathy were observed. The perfectly symmetric SSEP responses for the sural, lateral femoral cutaneous, and posterior tibial nerves obviate a central, and substantiate a peripheral, cause for the altered right PFCN evoked response. PMID:2827603

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.).

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

The virologic synapse (VS), which is formed between a virus-infected and uninfected cell, plays a central role in the transmission of certain viruses, such as HIV and HTLV-1. During VS formation, HTLV-1-infected T-cells polarize cellular and viral proteins toward the uninfected T-cell. This polarization resembles anterior-posterior cell polarity induced by immunological synapse (IS) formation, which is more extensively characterized than VS formation and occurs when a T-cell interacts with an antigen-presenting cell. One measure of cell polarity induced by both IS or VS formation is the repositioning of the microtubule organizing center (MTOC) relative to the contact point with the interacting cell. Here we describe an automated, high throughput system to score repositioning of the MTOC and thereby cell polarity establishment. The method rapidly and accurately calculates the angle between the MTOC and the IS for thousands of cells. We also show that the system can be adapted to score anterior-posterior polarity establishment of epithelial cells. This general approach represents a significant advancement over manual cell polarity scoring, which is subject to experimenter bias and requires more time and effort to evaluate large numbers of cells. PMID:22355445

Irvin-Wilson, Charletha V; Newberg, Justin Y; Kong, Kathleen; Javier, Ronald T; Marriott, Susan J

The virologic synapse (VS), which is formed between a virus-infected and uninfected cell, plays a central role in the transmission of certain viruses, such as HIV and HTLV-1. During VS formation, HTLV-1-infected T-cells polarize cellular and viral proteins toward the uninfected T-cell. This polarization resembles anterior-posterior cell polarity induced by immunological synapse (IS) formation, which is more extensively characterized than VS formation and occurs when a T-cell interacts with an antigen-presenting cell. One measure of cell polarity induced by both IS or VS formation is the repositioning of the microtubule organizing center (MTOC) relative to the contact point with the interacting cell. Here we describe an automated, high throughput system to score repositioning of the MTOC and thereby cell polarity establishment. The method rapidly and accurately calculates the angle between the MTOC and the IS for thousands of cells. We also show that the system can be adapted to score anterior-posterior polarity establishment of epithelial cells. This general approach represents a significant advancement over manual cell polarity scoring, which is subject to experimenter bias and requires more time and effort to evaluate large numbers of cells.

Irvin-Wilson, Charletha V.; Newberg, Justin Y.; Kong, Kathleen; Javier, Ronald T.; Marriott, Susan J.

We propose a Bayesian image super-resolution (SR) method with a causal Gaussian Markov random field (MRF) prior. SR is a technique to estimate a spatially high-resolution image from given multiple low-resolution images. An MRF model with the line process supplies a preferable prior for natural images with edges. We improve the existing image transformation model, the compound MRF model, and its hyperparameter prior model. We also derive the optimal estimator--not the joint maximum a posteriori (MAP) or the marginalized maximum likelihood (ML) but the posterior mean (PM)--from the objective function of the L2-norm-based (mean square error) peak signal-to-noise ratio. Point estimates such as MAP and ML are generally not stable in ill-posed high-dimensional problems because of overfitting, whereas PM is a stable estimator because all the parameters in the model are evaluated as distributions. The estimator is numerically determined by using the variational Bayesian method. The variational Bayesian method is a widely used method that approximately determines a complicated posterior distribution, but it is generally hard to use because it needs the conjugate prior. We solve this problem with simple Taylor approximations. Experimental results have shown that the proposed method is more accurate or comparable to existing methods. PMID:22389146

The subjective and the objective aspects of probabilities are incorporated in a simple duality axiom inspired by observer participation in quantum theory. Transcending the classical notion of probabilities, it is proposed and demonstrated that all probabilities may be fundamentally quantum mechanical in the sense that they may all be derived from the corresponding amplitudes. The classical coin-toss and the quantum

Probability knowledge and skills are needed in science and in making daily decisions that are sometimes made under uncertain conditions. Hence, there is the need to ensure that the pre-service teachers of our children are well prepared to teach probability. Pre-service teachers' conceptions of probability are identified, and ways of helping them…

Recent research has clearly demonstrated that accurate cancer diagnosis is indeed possible based on gene expression analysis and a database of stored expression profiles from known cancerous tumors. While current techniques largely succeed in correctly identifying the class membership of a tumor among various classes of cancers from its gene expression profile, they do not provide a probability of membership

Balaji Krishnapuram; Alexander Hartemink; Lawrence Carin

A midline approach to the lumbar region is most frequently used for posterior lumbar spine surgery. The exposure of the deeper layer of muscles, however, is imprecise and can entail substantial tissue damage and blood loss. During 10 years of operative surgical experience, we have developed an improved and less traumatic technique for exposure of the lumbar transverse processes and intertransverse region in which the tendons of multifidus and longissimus muscles are isolated at every level and divided laterally to the facet joints. This method eases identification and accurate cauterisation of the subjacent arteries, thereby reducing tissue damage and blood loss. It takes no more time and clarifies the exposure of the lumbar transverse processes and intertransverse region. Cadaveric dissection confirms the muscular and arterial anatomy of the region. We recommend use of this modified approach to improve standard practice.

Weatherley, Christopher Roy; Emran, Ihab Mohammad; Newell, Richard Leonard Martyn

A 3-year-old boy presented with an asymptomatic intertesticular mass increasing in size. Plasma tumor markers (?-fetoprotein and ?-human chorionic gonadotrophin) were negative. The mass had a pattern similar to testicular parenchyma but no discernable blood flow on scrotal Doppler ultrasound. Magnetic resonance imaging scan showed that it reached the posterior urethra after passing through the right corpus cavernosum with a progressive tapering extending into the pelvis. The mass was excised surgically and histologically found to be consistent with a dermoid cyst. Such rare benign lesions should be considered in the differential diagnosis of painless scrotal masses in children. Its anatomy was accurately defined by magnetic resonance imaging and was essential to minimize the risk to adjacent structures. PMID:22901929

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

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

Microgravity exposure affects visual acuity in a subset of astronauts and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in the eyes of several astronauts. This phenomenon is known to affect some terrestrial patient populations and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT) or B-mode Ultrasound (US), without consistent objective criteria. NASA uses a semiquantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was ot initiate development of an objective quantification methodology to monitor small changes in posterior globe flattening.

Lumpkins, Sarah B.; Garcia, Kathleen M.; Sargsyan, Ashot E.; Hamilton, Douglas R.; Berggren, Michael D.; Ebert, Douglas

Cervical stenosis, especially of the upper cervical spine, is quite rare which can be developmental or acquired. Clefts or aplasias of anterior and posterior arches of atlas, ossification of the transverse atlantal ligament, hypertrophy of the dens and os odontoideum are rare conditions causing cervical myelopathy reported either singly or in combination. Hypertrophy of the posterior arch of atlas in the absence of any ring hypoplasia as a cause of cervical myelopathy has not been reported earlier. The authors report a case of cervical myelopathy in a 26-year-old female due to hypertrophied posterior arch of atlas which was preoperatively diagnosed as a bony tumor. Being aware of such an entity may avoid diagnostic surprises and facilitate patient prognostication and management.

Cervical stenosis, especially of the upper cervical spine, is quite rare which can be developmental or acquired. Clefts or aplasias of anterior and posterior arches of atlas, ossification of the transverse atlantal ligament, hypertrophy of the dens and os odontoideum are rare conditions causing cervical myelopathy reported either singly or in combination. Hypertrophy of the posterior arch of atlas in the absence of any ring hypoplasia as a cause of cervical myelopathy has not been reported earlier. The authors report a case of cervical myelopathy in a 26-year-old female due to hypertrophied posterior arch of atlas which was preoperatively diagnosed as a bony tumor. Being aware of such an entity may avoid diagnostic surprises and facilitate patient prognostication and management. PMID:23275813

Kasliwal, Manish Kumar; Traynelis, Vincent Charles

Trauma is the prime causative factor for fracture of teeth/dentition. Many procedural management options are followed successfully in relation to the anterior teeth. However, most posterior cases where the tooth is fractured have only limited options to pursue to save the tooth. Fractured teeth, whether they are vital/non-vital, are predominantly managed with surgical options. This paper discusses a conservative approach to reattaching a split posterior tooth. A split tooth situation is mostly an absolute indication for extraction, but the clinician may go in for extensive surgical procedures if he/she wishes to save it. The reattachment of the tooth can be successfully done and it can be put to function. This paper discusses how a split posterior tooth can be treated successfully, although depending on multiple factors. A full crown cemented after successful reattachment and root canal therapy would provide sufficient support in order for the tooth to heal. PMID:25080545

A 14-year-old boy presented with a very rare meningioma in the posterior cranial fossa without dural attachment. Magnetic resonance imaging revealed a 3-cm, well-circumscribed, heterogeneously enhanced, round mass without dural tail sign in the right side of the posterior fossa. Right vertebral angiography revealed very faint tumor staining supplied by the right posterior inferior cerebellar artery. Total removal of the tumor was performed. Intraoperatively, the mass exhibited no attachment to the dura mater, cerebellar parenchyma, or choroid plexus, but was firmly attached to the arachnoid tissue near the foramen of Luschka. Histological and immunohistochemical studies established the diagnosis of meningothelial meningioma (World Health Organization grade I). PMID:17721053

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

Microgravity exposure affects visual acuity in a subset of astronauts, and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in several astronauts. This phenomenon is known to affect some terrestrial patient populations, and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT), or B-mode ultrasound (US), without consistent objective criteria. NASA uses a semi-quantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was to initiate development of an objective quantification methodology for posterior globe flattening.

Lumpkins, S. B.; Garcia, K. M.; Sargsyan, A. E.; Hamilton, D. R.; Berggren, M. D.; Antonsen, E.; Ebert, D.

Conventional analyses of the accuracy of phase-measurement interferometry derive a figure of merit that is either a variance or a signal-to-noise ratio. We derive the probability-density function of the phase-measurement output, so that the measurement confidence interval can be determined. We include both laser phase noise and additive Gaussian noise, and we consider both unmodulated interferometers and those employing phase or frequency modulation. For both unmodulated and modulated interferometers the confidence interval can be obtained by numerical integration of the probability-density function. For the modulated interferometer we derive a series summation for the confidence interval. For both unmodulated and modulated interferometers we derive approximate analytical expressions for the confidence interval, which we show to be extremely accurate at high signal-to-noise ratios.

The present study with college students examined the effect of amount on the discounting of probabilistic monetary rewards. A hyperboloid function accurately described the discounting of hypothetical rewards ranging in amount from $20 to $10,000,000. The degree of discounting increased continuously with amount of probabilistic reward. This effect of amount was not due to changes in the rate parameter of the discounting function, but rather was due to increases in the exponent. These results stand in contrast to those observed with the discounting of delayed monetary rewards, in which the degree of discounting decreases with reward amount due to amount-dependent decreases in the rate parameter. Taken together, this pattern of results suggests that delay and probability discounting reflect different underlying mechanisms. That is, the fact that the exponent in the delay discounting function is independent of amount is consistent with a psychophysical scaling interpretation, whereas the finding that the exponent of the probability-discounting function is amount-dependent is inconsistent with such an interpretation. Instead, the present results are consistent with the idea that the probability-discounting function is itself the product of a value function and a weighting function. This idea was first suggested by Kahneman and Tversky (1979), although their prospect theory does not predict amount effects like those observed. The effect of amount on probability discounting was parsimoniously incorporated into our hyperboloid discounting function by assuming that the exponent was proportional to the amount raised to a power. The amount-dependent exponent of the probability-discounting function may be viewed as reflecting the effect of amount on the weighting of the probability with which the reward will be received. PMID:21541126

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.

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

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

The authors report the case of a patient with Chiari malformation Type I (CM-I) and syringomyelia probably caused by a retrocerebellar arachnoid cyst. The patient's phenotype corresponded to trichorhinophalangeal syndrome Type I. The authors attributed the origin of both the retrocerebellar cyst and the abnormal posterior fossa to endochondral ossification anomalies that occur in this syndrome. The patient's spinal pain was most likely a result of the combination of CM-I and syringomyelia. To the best of the authors' knowledge, this is the first report on the association of CM-I and syringomyelia with a retrocerebellar arachnoid cyst occurring in a patient with trichorhinophalangeal syndrome Type I. The authors discuss the pathogenetic mechanisms involved in the production of tonsillar descent and syringomyelia in this patient, and review the current literature on related conditions that can result in this association. PMID:18826365

Martínez-Lage, Juan F; Ruiz-Espejo, Antonio; Guillén-Navarro, Encarna; Almagro, María-José

Posterior urethral valve (PUV) is a condition that leads to characteristic changes in the bladder and upper urinary tract. Dysfunction of the bladder such as a hyperreflective, hypertonic, and small capacity bladder as well as sphincter incompetence and/or myogenic failure should be adequately treated. Poor compliance/small bladder could be treated with anticholinergics, but bladder augmentation will probably be indicated. Although bladder reconstruction with gastrointestinal segments can be associated with multiple complications, including metabolic disorders, calculus formation, mucus production, enteric fistulas, and malignancy formation, enterocystoplasty is still the gold standard. In contrast to a neuropathic or exstrophic bladder, augmentation of the valve bladder allows spontaneous voiding without significant residual urine in the majority of cases, but some require CIC (clean intermittent cathterization). Augmentation cystoplasty is also an efficient approach in those children who will require kidney transplantation in the future.

Object The object of this paper was to describe the surgical anatomy and technical nuances of the endonasal transcavernous posterior clinoidectomy approach with interdural pituitary transposition and to report the clinical outcome of this technical modification. Methods The surgical anatomy of the proposed approach was studied in 10 colored silicon-injected anatomical specimens. The medical records of 12 patients that underwent removal of the posterior clinoid(s) with this technique were reviewed. Results The natural anatomical corridor provided by the cavernous sinus is used to get access to the posterior clinoid by mobilizing the pituitary gland in an interdural fashion. The medial wall of the cavernous sinus is preserved intact and attached to the gland during its medial and superior mobilization. This provides protection to the gland, allowing for preservation of its venous drainage pathways. The inferior hypophyseal artery is transected to facilitate the manipulation of the medial wall of the cavernous sinus and pituitary gland. This approach was successfully performed in all patients, including 6 with chordomas, 5 with petroclival meningiomas, and 1 with an epidermoid tumor. No patient in this series had neurovascular injury related to the posterior clinoidectomy. There were no instances of permanent hypopituitarism or diabetes insipidus. Conclusions The authors introduce a surgical variant of the endoscopic endonasal posterior clinoidectomy approach that does not require intradural pituitary transposition and is more effective than the purely extradural approach. The endoscopic endonasal transcavernous approach facilitates the removal of prominent posterior clinoids increasing the working space at the lateral recess of the interpeduncular cistern, while preserving the pituitary function. PMID:24816325

Fernandez-Miranda, Juan C; Gardner, Paul A; Rastelli, Milton M; Peris-Celda, Maria; Koutourousiou, Maria; Peace, David; Snyderman, Carl H; Rhoton, Albert L

Clunealgia is caused by neuropathy of inferior cluneal branches of the posterior femoral cutaneous nerve resulting in pain in the inferior gluteal region. Image-guided anesthetic nerve injections are a viable and safe therapeutic option in sensory peripheral neuropathies that provides significant pain relief when conservative therapy fails and surgery is not desired or contemplated. The authors describe two cases of clunealgia, where computed-tomography-guided technique for nerve blocks of the posterior femoral cutaneous nerve and its branches was used as a cheaper, more convenient, and faster alternative with similar face validity as the previously described magnetic-resonance-guided injection. PMID:24667042

Kasper, Jared M; Wadhwa, Vibhor; Scott, Kelly M; Chhabra, Avneesh

We report one case of posterior fossa intracranial haemorrhage in a full-term Malay baby boy following vacuum assisted delivery. The patient, a term baby boy was delivered by a vacuum extraction and later developed signs of increased intracranial pressure 72 hours after birth. Computed tomography (CT) of the brain showed a posterior fossa intracranial haemorrhage with acute obstructive hydrocephalus. He was initially treated with isolated ventricular shunting which later caused an upward cerebellar herniation. An immediate suboccipital craniectomy for evacuation of cerebellar haematoma was performed which resulted in a gradual recovery. PMID:16708744

A wide and redundant prolapse of the posterior mitral leaflet in active infective endocarditis cannot be easily repaired. A sliding plasty can be attempted, but the range of annular plication is often too large. Chordal replacement is another option, but is prone to long-term degeneration because the redundant leaflet still exists. Here, we describe a simple resection technique that utilizes only two small triangular resections. The resections are sutured with no need to shorten the annulus. The leaflet tissue between the two triangular resections must be preserved to make an appropriately shaped posterior leaflet. PMID:23223672

Posterior reversible encephalopathy syndrome (PRES) is a rare clinicoradiologic condition manifesting with headache, seizures, altered sensorium, visual disturbances, and characteristic lesions on neuroimaging predominantly affecting the posterior regions of the brain. We report a case of an 8-year-old boy with poststreptococcal glomerulonephritis, presenting as PRES. A magnetic resonance imaging showed hyperintense lesions in bilateral frontal and parietooccipital parenchyma on fluid-attenuated inversion recovery and T2-weighted images, suggestive of “PRES.” Patient made a complete neurological recovery without any deficit.

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

OBJECTIVE. The purpose of this video article is to demonstrate sonographic anatomy at the posterior hip and to describe a number of diagnostic and therapeutic interventions that may be performed at this location with sonographic guidance. Injection techniques at the piriformis muscle, ischial bursa, hamstring origin, and ischiofemoral space are described and demonstrated. CONCLUSION. Ultrasound is well adapted to the evaluation and treatment of conditions encountered at the posterior hip. Sonographic guidance is a useful tool that allows a trained operator to safely and effectively perform a range of injections. PMID:24848848

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

Posterior approaches for decompression in minimally invasive spine surgery are increasingly used for a wide range of pathology. Surgeons and patients must understand these risks in order to identify, manage, and ideally prevent complications. Technical intraoperative complications, recurrences and reoperations, infections, and medical complications associated with the surgery are considered for common posterior minimally invasive decompression procedures of the cervical and lumbar spine. Methods of possibly avoiding these complications are also discussed. This article then aggregates the relevant data to allow concise understanding of the complications associated with these procedures. PMID:24703443

Stadler, James A; Wong, Albert P; Graham, Randall B; Liu, John C

Reversible posterior leucoencephalopathy and cerebral venous thrombosis share many symptoms. Both of them may lead to coma, and cause epilepsy or focal neurological signs. Moreover, diffuse leucoencephalopathy can be observed in both cases. Cerebral venous thrombosis needs anticoagulation which is not a riskless treatment. We describe a case of reversible posterior leucoencephalopathy in an hypertensed, seventy-year old man, presenting with a left lateral sinus hypoplasia whose clinical history and paramedical results first suggested a cerebral veinous thrombosis. Our case shows the misleadings a congenital vascular asymmetry can induce when confronted with a subacute coma. PMID:16894957

Naeije, G; Hanappe, V; Laureys, M; Masudi, J; Vokaer, M; Bier, J C

Posterior reversible encephalopathy syndrome (PRES) is a rare clinicoradiologic condition manifesting with headache, seizures, altered sensorium, visual disturbances, and characteristic lesions on neuroimaging predominantly affecting the posterior regions of the brain. We report a case of an 8-year-old boy with poststreptococcal glomerulonephritis, presenting as PRES. A magnetic resonance imaging showed hyperintense lesions in bilateral frontal and parietooccipital parenchyma on fluid-attenuated inversion recovery and T2-weighted images, suggestive of "PRES." Patient made a complete neurological recovery without any deficit. PMID:24891903

SIGMA PI is the fastest method available today of accurately calculating probabilities associated with large fault trees. To demonstrate this, we describe the major problems that have prevented successful evaluation of these probabilities by other methods in the past. Then, we describe how SIGMA PI addresses all of these problems, and we compare the performance of SIGMA PI with that of leading alternative methods under selected problem scenarios. 13 refs., 3 figs., 2 tabs.

Loss of vision in posterior uveitis is often the consequence of chronic retinal oedema and immune-mediated damage to the retinal parenchyma. Research in other putative autoimmune diseases such as rheumatoid arthritis, and in animal models of autoimmune disease, has uncovered a number of mechanisms which may contribute to the development of inflammatory disease within the eye. With recent developments in

This paper considers Bayesian counterparts of the classical tests for good- ness of fit and their use in judging the fit of a single Bayesian model to the observed data. We focus on posterior predictive assessment, in a framework that also includes conditioning on auxiliary statistics. The Bayesian formulation facilitates the con- struction and calculation of a meaningful reference distribution

BACKGROUND: Nausea and vomiting is a problem for children after neurosurgery and those requiring posterior fossa procedures appear to have a high incidence. This clinical observation has not been quantified nor have risk factors unique to this group of children been elucidated. METHODS: A six year retrospective chart audit at two Canadian children's hospitals was conducted. The incidence of nausea

Susan M Neufeld; Christine V Newburn-Cook; Donald Schopflocher; Belinda Dundon; Herta Yu; Jane E Drummond

Lung hernias are rare, occurring most commonly after trauma or surgery. Spontaneous lung hernias are even rarer and have only been reported as occurring anteriorly. We present a 72-year-old male who developed a spontaneous posterior lung hernia after a severe coughing episode. We describe the evaluation and surgical management of this unusual condition and provide a brief review of the literature.

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, visual loss, and characteristic imaging pattern in brain MRI. The cause of PRES is not yet understood. We report a case of a 27-year-old woman that developed PRES after the use of FOLFOX 5 (oxaliplatin/5-Fluoracil/Leucovorin) chemotherapy for a colorectal cancer.

Porcello Marrone, Luiz Carlos; Marrone, Bianca Fontana; Pascoal, Tharick Ali; Schilling, Lucas Porcello; Soder, Ricardo Bernardi; Ferreira, Sheila Schuch; Gadonski, Giovani; da Costa, Jaderson Costa

Posterior reversible leukoencephalopathy syndrome (PRLS) is a neurologic condition, often presents with various clinical manifestations. It is rare during pregnancy. We herein report a case of PRLS in a 31-year-old woman, presented with preeclampsia, diagnosed by computer tomography, and successfully delivered the baby with caesarean section. At discharge, patient was fully recovered without any complication.

Many surgical techniques have been described in the management of posteriorly dislocated intraocular lens (IOLs). Lifting the IOL off the retina is a critical step during the surgical procedure. We describe a new simple and effective technique using an extrusion cannula that offers many advantages to lift the IOL in a safer and more controlled way. PMID:11371099

Closed posterior dislocation of the ankle without a fracture is a rare injury. We are reporting a case in a young male on his motorbike, being hit at the right ankle from behind. The mechanisms of injury along with MRI findings are being discussed.

Purpose: In patients with cervical spinal stenosis, the posterior laminectomy represents a surgical alternative to anterior procedures. Whereas the majority of surgeons prefer anterior procedures to treat mono- to three-segmental pathologies, posterior procedures have several advantages if the pathology includes four or more segments. Indication: In general, the indications for a posterior laminectomy resemble those for anterior procedures. Specifically patients with multisegmental pathologies benefit from a shorter operative time as well as reduced perioperative morbidity. Method: A midline incision is made and followed by subperiostal exposure of the cervical spine. Facet decortication and screw hole preparation can be performed if a fusion is required. The lamina is now separated from the lateral mass using a high-speed burr and elevated en bloc from the dura. The fusion can now be completed. Conclusion: The posterior en bloc laminectomy with or without fusion represents a viable alternative to anterior procedures in patients with a cervical spinal canal stenosis. It often is the technique of choice for treating more than 3 levels. PMID:24960087

The horizontal saccade, smooth pursuit, and vestibulo-ocular reflex gains were recorded in 19 patients with cerebellar infarction documented with MRI, and in a group of control subjects. Bilateral saccade hypometria and a decrease in ipsilateral smooth pursuit gain were found only in patients with a lesion affecting the posterior vermis. These results in humans support experimental findings suggesting that the

K. Vahedi; S. Rivaud; P. Amarenco; C. Pierrot-deseilligny

The majority of posterior inferior cerebellar artery (PICA) aneurysms are usually found on the bifurcation of the vertebral artery (VA) - PICA junction. Aneurysms arising from more peripheral PICA seg- ments named distal PICA aneurysm are uncommon. The major clinical manifestation is that of an intracra- nial bleeding and the site of hemorrhage is related to the PICA segment originating

Ricardo Ramina; Viviane Aline Buffon; Jerônimo Buzetti Milano; Erasmo Barros da Silva Jr; Kelly Cristina Bordignon

The role of augmentation cystoplasty in the neuropathic and exstrophy bladder has been well documented. However, its place and the timing of such surgery in the “valve bladder” are not well established. We report our experience with augmentation cystoplasty in 20 boys with previously treated posterior urethral valves. Urodynamic studies confirmed poorly compliant, unstable bladders with low functional capacities, which

A. M. Kajbafzadeh; F. M. J. Quinn; P. G. Duffy; P. G. Ransley

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.

Purpose: To evaluate the technique of silicone oil removal through a posterior capsulorhexis combined with phacoemulsification and intraocular lens (IOL) implantation.Setting: Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India.Methods: Fifteen eyes of 15 patients had phacoemulsification with removal of silicone oil, which had been used for intraocular tamponade after a previous pars plana vitrectomy. Eyes with a stable

Vijay K Dada; Dinesh Talwar; Namrata Sharma; Tanuj Dada; Rajeev Sudan; Raj Vardhan Azad

Mild cognitive impairment in Parkinson's disease (PD) is heterogeneous in regard to affected domains. Although patterns of cognitive performance that may predict later dementia are as yet undetermined, posterior-versus frontal-type assessments show promise for differential predictive value. The present study included 70 individuals: 42 with idiopathic PD without dementia and 28 age- and education-matched healthy control adults (HC). Participants completed assessments of cognition with emphasis on tests that are sensitive to frontal and posterior deficits. PD patients were classified into cognitive subgroups and the subgroups were compared on demographic and disease variables. Individual performance across neuropsychological tests was evaluated for the PD group. Patients with PD performed more poorly than HC on several measures of cognition, and they were classified into frontal (12), posterior (3), both (10) and neither subgroups (17), the latter two in reference to frontal- and posterior-type deficits. The neither subgroup was distinguished by less motor impairment than the both subgroup, but the four subgroups did not otherwise differ on demographic or disease variables. Across patients, the tests most sensitive to cognitive impairment included measures of attention and executive functioning (frontal-type tests). Examination of individual test performance for PD revealed substantial heterogeneity across tests with respect to number and severity of deficits. The current study provides insight into which commonly used neuropsychological tests are most sensitive to cognitive deficits (strictly defined) in a nondemented, well characterized PD sample, and into the relation of cognitive subgroups to demographic and disease-specific variables.

Miller, Ivy N.; Neargarder, Sandy; Risi, Megan M.; Cronin-Golomb, Alice

The author describes a protocol for classroom experiments for courses that introduce undergraduates to signaling games. Signaling games are conceptually difficult because, when analyzing the game, students are not naturally inclined to think in probabilistic, Bayesian terms. The experimental design explicitly presents the posterior frequencies of…

We present a case report to remind surgeons of this unusual complication that can occur in any surgery, even posterior cervical spine surgery under general anesthesia and discuss its causes, treatment methods, and the follow-up results in the literature. The peripheral Tapia's syndrome is a rare complication of anesthetic airway management. Main symptoms are hoarseness of voice and difficulty of tongue movement. Tapia's syndrome after endotracheal general anesthesia is believed to be due to pressure neuropathy of the vagus nerve and the hypoglossal nerve caused by the endotracheal tube. To our knowledge, no report has been published or given an explanation for Tapia's syndrome after posterior cervical spine surgery. Two patients who underwent posterior cervical surgery complained hoarseness and tongue palsy postoperatively. There is no direct anatomical relation between the operation, the vagus nerves and the hypoglossal nerves, and there is no record of displacement or malposition of the endotracheal tube. After several months, all symptoms are resolved. To avoid this problem in posterior cervical spine surgery, we suggest paying special attention to the position of the endotracheal tube to avoid excessive neck flexion before and during the positioning of the patient.