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Sample records for accurate posterior probability

  1. Children's Understanding of Posterior Probability

    ERIC Educational Resources Information Center

    Girotto, Vittorio; Gonzalez, Michael

    2008-01-01

    Do young children have a basic intuition of posterior probability? 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,…

  2. RESEARCH ARTICLE Posterior Probability Matching and Human

    E-print Network

    Murray, Richard

    RESEARCH ARTICLE Posterior Probability Matching and Human Perceptual Decision Making Richard F making that was first developed in mod- els of cognition. Posterior probability matching, a variant probability matching behaviour, and our meth- ods provide new tools for testing for such a strategy. Author

  3. Confidence measures from local posterior probability estimates 

    E-print Network

    Williams, Gethin; Renals, Steve

    1999-01-01

    In this paper we introduce a set of related confidence measures for large vocabulary continuous speech recognition (LVCSR) based on local phone posterior probability estimates output by an acceptor HMM acoustic model. In ...

  4. Posterior Probabilities for a Consensus Ordering.

    ERIC Educational Resources Information Center

    Fligner, Michael A.; Verducci, Joseph S.

    1990-01-01

    The concept of consensus ordering is defined, and formulas for exact and approximate posterior probabilities for consensus ordering are developed under the assumption of a generalized Mallows' model with a diffuse conjugate prior. These methods are applied to a data set concerning 98 college students. (SLD)

  5. GNSS integer ambiguity validation based on posterior probability

    NASA Astrophysics Data System (ADS)

    Wu, Zemin; Bian, Shaofeng

    2015-10-01

    GNSS integer ambiguity validation is considered to be a challenge task for decades. Several kinds of validation tests are developed and widely used in these years, but theoretical basis is their weakness. Ambiguity validation theoretically is an issue of hypothesis test. In the frame of Bayesian hypothesis testing, posterior probability is the canonical standard that statistical decision should be based on. In this contribution, (i) we derive the posterior probability of the fixed ambiguity based on the Bayesian principle and modify it for practice ambiguity validation. (ii) The optimal property of the posterior probability test is proved based on an extended Neyman-Pearson lemma. Since validation failure rate is the issue users most concerned about, (iii) we derive the failure rate upper bound of the posterior probability test, so the user can use the posterior probability test either in the fixed posterior probability or in the fixed failure rate way. Simulated as well as real observed data are used for experimental validations. The results show that (i) the posterior probability test is the most effective within the R-ratio test, difference test, ellipsoidal integer aperture test and posterior probability test, (ii) the posterior probability test is computational efficient and (iii) the failure rate estimation for posterior probability test is useful.

  6. Posterior Probability Matching and Human Perceptual Decision Making

    PubMed Central

    Murray, Richard F.; Patel, Khushbu; Yee, Alan

    2015-01-01

    Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models’ performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods provide new tools for testing for such a strategy. PMID:26079134

  7. Posterior Probability Estimation Techniques Embedded in a Bayes Filter for Vibration-based

    E-print Network

    Zell, Andreas

    Posterior Probability Estimation Techniques Embedded in a Bayes Filter for Vibration-based Terrain Classification Philippe Komma and Andreas Zell Abstract Vibration signals acquired during robot traversal provide] or ladar sensors [15, 10] can be employed. Recently, several researchers considered vehicle vibrations

  8. Performance of the Rayleigh task based on the posterior probability of tomographic reconstructions

    SciTech Connect

    Hanson, K.M.

    1991-01-01

    We seek the best possible performance of the Rayleigh task in which one must decide whether a perceived object is a pair of Gaussian-blurred points or a blurred line. Two Bayesian reconstruction algorithms are used, the first based on a Gaussian prior-probability distribution with a nonnegativity constraint and the second based on an entropic prior. In both cases, the reconstructions are found that maximize the posterior probability. We compare the performance of the Rayleigh task obtained with two decision variables, the logarithm of the posterior probability ratio and the change in the mean-squared deviation from the reconstruction. The method of evaluation is based on the results of a numerical testing procedure in which the stated discrimination task is carried out on reconstructions of a randomly generated sequence of images. The ability to perform the Rayleigh task is summarized in terms of a discrimination index that is derived from the area under the receiver-operating characteristic (ROC) curve. We find that the use of the posterior probability does not result in better performance of the Rayleigh task than the mean-squared deviation from the reconstruction. 10 refs., 6 figs.

  9. Accurate photometric redshift probability density estimation - method comparison and application

    NASA Astrophysics Data System (ADS)

    Rau, Markus Michael; Seitz, Stella; Brimioulle, Fabrice; Frank, Eibe; Friedrich, Oliver; Gruen, Daniel; Hoyle, Ben

    2015-10-01

    We introduce an ordinal classification algorithm for photometric redshift estimation, which significantly improves the reconstruction of photometric redshift probability density functions (PDFs) for individual galaxies and galaxy samples. As a use case we apply our method to CFHTLS galaxies. The ordinal classification algorithm treats distinct redshift bins as ordered values, which improves the quality of photometric redshift PDFs, compared with non-ordinal classification architectures. We also propose a new single value point estimate of the galaxy redshift, which can be used to estimate the full redshift PDF of a galaxy sample. This method is competitive in terms of accuracy with contemporary algorithms, which stack the full redshift PDFs of all galaxies in the sample, but requires orders of magnitude less storage space. The methods described in this paper greatly improve the log-likelihood of individual object redshift PDFs, when compared with a popular neural network code (ANNZ). In our use case, this improvement reaches 50 per cent for high-redshift objects (z ? 0.75). We show that using these more accurate photometric redshift PDFs will lead to a reduction in the systematic biases by up to a factor of 4, when compared with less accurate PDFs obtained from commonly used methods. The cosmological analyses we examine and find improvement upon are the following: gravitational lensing cluster mass estimates, modelling of angular correlation functions and modelling of cosmic shear correlation functions.

  10. eProbalign: generation and manipulation of multiple sequence alignments using partition function posterior probabilities

    PubMed Central

    Chikkagoudar, Satish; Roshan, Usman; Livesay, Dennis

    2007-01-01

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

  11. Searching for evolutionary distant RNA homologs within genomic sequences using partition function posterior probabilities

    PubMed Central

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

    2008-01-01

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

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

    PubMed Central

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

    2008-01-01

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

  13. A Posterior Probability-based System Hybridisation and Combination for Spoken Term Detection 

    E-print Network

    Tejedor, Javier; Wang, Dong; King, Simon; Frankel, Joe; Colas, Jose

    2009-01-01

    Spoken term detection (STD) is a fundamental task for multimedia information retrieval. To improve the detection performance, we have presented a direct posterior-based confidence measure generated from a neural network. ...

  14. On the use of posterior predictive probabilities and prediction uncertainty to tailor informative sampling for parasitological surveillance in livestock.

    PubMed

    Musella, Vincenzo; Rinaldi, Laura; Lagazio, Corrado; Cringoli, Giuseppe; Biggeri, Annibale; Catelan, Dolores

    2014-09-15

    Model-based geostatistics and Bayesian approaches are appropriate in the context of Veterinary Epidemiology when point data have been collected by valid study designs. The aim is to predict a continuous infection risk surface. Little work has been done on the use of predictive infection probabilities at farm unit level. In this paper we show how to use predictive infection probability and related uncertainty from a Bayesian kriging model to draw a informative samples from the 8794 geo-referenced sheep farms of the Campania region (southern Italy). Parasitological data come from a first cross-sectional survey carried out to study the spatial distribution of selected helminths in sheep farms. A grid sampling was performed to select the farms for coprological examinations. Faecal samples were collected for 121 sheep farms and the presence of 21 different helminths were investigated using the FLOTAC technique. The 21 responses are very different in terms of geographical distribution and prevalence of infection. The observed prevalence range is from 0.83% to 96.69%. The distributions of the posterior predictive probabilities for all the 21 parasites are very heterogeneous. We show how the results of the Bayesian kriging model can be used to plan a second wave survey. Several alternatives can be chosen depending on the purposes of the second survey: weight by posterior predictive probabilities, their uncertainty or combining both information. The proposed Bayesian kriging model is simple, and the proposed samping strategy represents a useful tool to address targeted infection control treatments and surbveillance campaigns. It is easily extendable to other fields of research. PMID:25131190

  15. Estimation of genotype distributions and posterior genotype probabilities for beta-mannosidosis in Salers cattle.

    PubMed

    Taylor, J F; Abbitt, B; Walter, J P; Davis, S K; Jaques, J T; Ochoa, R F

    1993-11-01

    beta-Mannosidosis is a lethal lysosomal storage disease inherited as an autosomal recessive in man, cattle and goats. Laboratory assay data of plasma beta-mannosidase activity represent a mixture of homozygous normal and carrier genotype distributions in a proportion determined by genotype frequency. A maximum likelihood approach employing data transformations for each genotype distribution and assuming a diallelic model of inheritance is described. Estimates of the transformation and genotype distribution parameters, gene frequency, genotype fitness and carrier probability were obtained simultaneously from a sample of 2,812 observations on U.S. purebred Salers cattle with enzyme activity, age, gender, month of pregnancy, month of testing, and parents identified. Transformations to normality were not required, estimated gene and carrier genotype frequencies of 0.074 and 0.148 were high, and the estimated relative fitness of heterozygotes was 1.36. The apparent overdominance in fitness may be due to a nonrandom sampling of progeny genotypes within families. The mean of plasma enzyme activity was higher for males than females, higher in winter months, lower in summer months and decreased with increased age. Estimates of carrier probabilities indicate that the test is most effective when animals are sampled as calves, although effectiveness of the plasma assay was less for males than females. Test effectiveness was enhanced through averaging repeated assays of enzyme activity on each animal. Our approach contributes to medical diagnostics in several ways. Rather than assume underlying normality for the distributions comprising the mixture, we estimate transformations to normality for each genotype distribution simultaneously with all other model parameters. This process also excludes potential biases due to data preadjustment for systematic effects. We also provide a method for partitioning phenotypic variation within each genotypic distribution which allows an assessment of the value of repeat measurements of the predictive variable for genotype assignment. PMID:8293984

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    E-print Network

    Kwok, James Tin-Yau

    Bayes classifier, are unable to produce ac- curate probability estimates [Niculescu-Mizil and Caruana not be the right transformation for many classifiers [Niculescu-Mizil and Caruana, 2005]. Isotonic regression increasing with the score. It has demonstrated great empirical success on various classifiers [Niculescu

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

    E-print Network

    Gross, Louis J.

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

  19. Fig. S1: Study of the histogram of the distribution of values { };0 ;1 500i N i N N represented in Fig. 2. A. Logarithm of the posterior probability (LPP) of bin number N

    E-print Network

    Michalet, Xavier

    Fig. S1: Study of the histogram of the distribution of values { };0 ;1 500i N i N N represented in Fig. 2. A. Logarithm of the posterior probability (LPP) of bin number N (as defined in ref. 36 of the distribution (as represented in Fig. 2) starts to appear at such a binning resolution. Fig. S2: Simplified

  20. Posterior Uveitis.

    PubMed

    Uy, Harvey Siy; Yu-Keh, Ellen; Chan, Pik Sha

    2016-01-01

    Posterior uveitis is a major cause of ocular morbidity worldwide. Systemic corticosteroids (CS) remain the primary method of treatment for noninfectious posterior uveitis; however, CS are associated with many side effects. Immunomodulatory therapy (IMT) is recommended when inflammatory control is not attained with a tolerable level of systemic CS (<10 mg/day of prednisone). IMT agents are associated with several toxicities and limited benefits in some patients. Locally administered therapies (e.g. intravitreal CS implants) offer the promise of providing therapeutic levels of anti-inflammatory agents while avoiding systemic complications. This chapter will briefly discuss common posterior uveitis entities that are amenable to retinal pharmacotherapy. PMID:26502276

  1. The Value of Accurate Magnetic Resonance Characterization of Posterior Cruciate Ligament Tears in the Setting of Multiligament Knee Injury: Imaging Features Predictive of Early Repair vs Reconstruction.

    PubMed

    Goiney, Christoper C; Porrino, Jack; Twaddle, Bruce; Richardson, Michael L; Mulcahy, Hyojeong; Chew, Felix S

    2016-01-01

    Multiligament knee injury (MLKI) represents a complex set of pathologies treated with a wide variety of surgical approaches. If early surgical intervention is performed, the disrupted posterior cruciate ligament (PCL) can be treated with primary repair or reconstruction. The purpose of our study was to retrospectively identify a critical length of the distal component of the torn PCL on magnetic resonance imaging (MRI) that may predict the ability to perform early proximal femoral repair of the ligament, as opposed to reconstruction. A total of 50 MLKIs were managed at Harborview Medical Center from May 1, 2013, through July 15, 2014, by an orthopedic surgeon. Following exclusions, there were 27 knees with complete disruption of the PCL that underwent either early reattachment to the femoral insertion or reconstruction and were evaluated using preoperative MRI. In a consensus fashion, 2 radiologists measured the proximal and distal fragments of each disrupted PCL using preoperative MRI in multiple planes, as needed. MRI findings were correlated with what was performed at surgery. Those knees with a distal fragment PCL length of ?41mm were capable of, and underwent, early proximal femoral repair. With repair, the distal stump was attached to the distal femur. Alternatively, those with a distal PCL length of ?32mm could not undergo repair because of insufficient length and as such, were reconstructed. If early surgical intervention for an MLKI involving disruption of the PCL is considered, attention should be given to the length of the distal PCL fragment on MRI to plan appropriately for proximal femoral reattachment vs reconstruction. If the distal PCL fragment measures ?41mm, surgical repair is achievable and can be considered as a surgical option. PMID:26183069

  2. A Posterior Approach for Microphone Array Based Speech Recognition 

    E-print Network

    Wang, Dong; Himawan, Ivan; Frankel, Joe; King, Simon

    2008-01-01

    posterior-based approach for array-based speech recognition. The main idea is, instead of enhancing speech signals, we try to enhance the posterior probabilities that frames belonging to recognition units, e.g., phones. These enhanced posteriors...

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

    E-print Network

    Gross, Louis J.

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

  4. Intraoperative posterior capsule flutter in posterior lentiglobus.

    PubMed

    Praveen, Mamidipudi R; Vasavada, Abhay R; Koul, Archana; Ravat, Farida A; Trivedi, Rupal H; Shah, Sajani K; Vasavada, Vaishali A

    2010-08-01

    Posterior capsules of pediatric eyes with lens disorders have complex morphological variations with differing etiologies and visual prognoses. We describe a unique case of intraoperative posterior capsule flutter in an eye of a child undergoing cataract surgery, which we interpret as a possible expression of posterior lentiglobus. PMID:20598928

  5. Efficient search using posterior phone probability estimates. 

    E-print Network

    Renals, Steve; Hochberg, Mike

    1995-01-01

    relative search error. Results from a hybrid system are presented using the Wall Street Journal LVCSR database for a 20,000 word task using a backed-off trigram language model. For this task, our single-pass decoder took around 15 times realtime on an HP735...

  6. Posterior ankle impingement in dancers and athletes.

    PubMed

    Roche, Andrew J; Calder, James D F; Lloyd Williams, R

    2013-06-01

    The diagnosis of posterior ankle impingement requires an accurate history and specific examination. Computed tomography is a useful investigation to diagnose bony impingement, especially where plain radiography and/or magnetic resonance imaging are sometimes inconclusive. Accurate ultrasound-guided steroid/anesthetic injections are useful interventions to locate the symptomatic lesions and reduce symptoms and occasionally prove curative. If surgical debridement or excision is deemed necessary, arthroscopic surgery via a posterior approach is recommended to excise impingement lesions with a quicker return to sport expected and minimal complications. Open surgical excision, however, remains a viable treatment option. PMID:23707179

  7. Cerulean posterior capsule opacity.

    PubMed

    Rhee, Miran; Oetting, Thomas A

    2007-09-01

    We present a case of light-blue posterior capsule opacification (PCO) in a patient who had cerulean cataracts removed 1 year earlier. The color of the PCO was similar to that of the cerulean cataracts prior to extraction. Posterior capsule opacification is a common complication after cataract surgery; however, we could not find a similar case of cerulean posterior capsule opacity in the literature. The findings in this case suggest that the mechanism of the light-blue color formation in the cataract was also present in the lens epithelial cells forming the posterior capsule opacity. PMID:17720089

  8. Posterior pharyngeal wall augmentation.

    PubMed

    Perez, Colleen F; Brigger, Matthew T

    2015-01-01

    Posterior pharyngeal wall augmentation is a useful technique in selected patients with velopharyngeal insufficiency who have a small central velopharyngeal gap. Options for augmenting this region include using posterior pharyngeal wall flaps to create bulk and implanting various materials to fill in the central deficiency. Autologous and nonautologous implant materials are available and may be implanted through an incision or directly injected into the posterior pharyngeal wall. Previously described materials for implantation include cartilage, fat, fascia, silicone, acellular dermis, polytetrafluoroethylene, and calcium hydroxyapatite. Patient evaluation and surgical techniques for posterior pharyngeal wall augmentation are described. PMID:25733235

  9. Normal Tissue Complication Probability Estimation by the Lyman-Kutcher-Burman Method Does Not Accurately Predict Spinal Cord Tolerance to Stereotactic Radiosurgery

    SciTech Connect

    Daly, Megan E.; Luxton, Gary; Choi, Clara Y.H.; Gibbs, Iris C.; Chang, Steven D.; Adler, John R.; Soltys, Scott G.

    2012-04-01

    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.

  10. Radiographic assessment of posterior malleolar ankle fractures.

    PubMed

    Gonzalez, Olga; Fleming, Justin J; Meyr, Andrew J

    2015-01-01

    The anatomy of the posterior tibial malleolus plays an important role in the structure and function of the ankle mortise. With specific respect to ankle fractures, the presence, size, and displacement of posterior malleolar fractures (Volkmann's fracture) helps determine which will be amendable to operative fixation. The objective of the present study was to increase the body of knowledge with respect to the ability of foot and ankle reconstructive surgeons to assess posterior malleolar ankle fractures using plain film radiography. Three different variables were investigated on Sawbones(®) models: (1) differing size of posterior malleolar fractures (10%, 25%, and 50% of the tibial plafond), (2) differing displacement of posterior malleolar fractures (0 and 5 mm of proximal displacement), and (3) 2 different radiographic projections (standard lateral and externally rotated lateral projections). Accurate identification of the posterior malleolar fracture occurred on 86.67% (26 of 30) of standard lateral radiographs and 100% (30 of 30) of externally rotated lateral radiographs. Furthermore, the surgeons described the fracture with greater precision and had greater interclass correlation coefficient values with respect to measurement of sagittal plane displacement (0.977 versus 0.939) and percentage of involvement of the tibial plafond (0.972 versus 0.775) with an externally rotated lateral projection compared with a standard lateral projection. Our results provide evidence that an externally rotated lateral radiographic projection can provide surgeons with some additional information with respect to the presence, size, and displacement of posterior malleolar ankle fractures. PMID:25262838

  11. Congenital basis of posterior fossa anomalies.

    PubMed

    Cotes, Claudia; Bonfante, Eliana; Lazor, Jillian; Jadhav, Siddharth; Caldas, Maria; Swischuk, Leonard; Riascos, Roy

    2015-06-01

    The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies. PMID:26246090

  12. Posterior shoulder approach.

    PubMed

    Norwood, L A; Matiko, J A; Terry, G C

    1985-12-01

    A posterior shoulder surgical approach combines the subperiosteal detachment of the deltoid from the scapular spine, described by McWhorter, with a lateral extension to include the lateral deltoid splitting of Codman. The glenohumeral joint is superiorly approached between the supraspinatus and infraspinatus tendons, or inferiorly between the infraspinatus and teres minor tendons. This approach was used in 42 shoulders with rotator cuff tears or posterior instability without complications of infection, failure of deltoid healing, or compromise of suprascapular or axillary nerves. This combined surgical approach provides excellent exposure of the superior and posterior shoulder, which is difficult to obtain by anterior or superior approaches. This approach may be used for repair of rotator cuff tears, posterior instability, and displaced posterior glenoid fractures. PMID:4064401

  13. Posterior polar cataracts: a predisposition to intraoperative posterior capsular rupture.

    PubMed

    Osher, R H; Yu, B C; Koch, D D

    1990-03-01

    We performed phacoemulsification or planned extracapsular cataract extraction on posterior polar cataracts in 31 eyes of 22 patients and experienced eight cases of posterior capsular rupture (26%). Capsular rupture occurred during removal of the posterior polar opacity or during cleaning of the posterior capsule after the opacity had been removed. We believe that excessive adherence of the opacity to the posterior capsule and unusual thinness of the capsule predisposed these eyes to posterior capsular rupture. PMID:2329471

  14. Posterior-based confidence measures for spoken term detection 

    E-print Network

    Wang, Dong; Tejedor, Javier; Frankel, Joe; King, Simon

    2009-01-01

    Confidence measures play a key role in spoken term detection (STD) tasks. The confidence measure expresses the posterior probability of the search term appearing in the detection period, given the speech. Traditional ...

  15. Posterior cruciate ligament (PCL) injury

    MedlinePLUS

    Cruciate ligament injury - posterior; PCL injury; Knee injury - posterior cruciate ligament (PCL); Hyperextended knee ... signs of PCL injury. This includes moving the knee joint in various ways. Your doctor may also ...

  16. Posterior Tibial Tendon Transfer.

    PubMed

    Shane, Amber M; Reeves, Christopher L; Cameron, Jordan D; Vazales, Ryan

    2016-01-01

    When performed correctly with the right patient population, a tibialis posterior muscle/tendon transfer is an effective procedure. Many different methods have been established for fixating the tendon, each of which has its' own indications. Passing through the interosseous membrane is the preferred and recommended method and should be used unless this is not possible. Good surgical planning based on patient needs and expectations, along with excellent postoperative care including early range of motion and physical therapy minimizes risk of complications and allows for the optimal outcome to be achieved. PMID:26590722

  17. Posterior Urethral Strictures

    PubMed Central

    Gelman, Joel; Wisenbaugh, Eric S.

    2015-01-01

    Pelvic fracture urethral injuries are typically partial and more often complete disruptions of the most proximal bulbar and distal membranous urethra. Emergency management includes suprapubic tube placement. Subsequent primary realignment to place a urethral catheter remains a controversial topic, but what is not controversial is that when there is the development of a stricture (which is usually obliterative with a distraction defect) after suprapubic tube placement or urethral catheter removal, the standard of care is delayed urethral reconstruction with excision and primary anastomosis. This paper reviews the management of patients who suffer pelvic fracture urethral injuries and the techniques of preoperative urethral imaging and subsequent posterior urethroplasty. PMID:26691883

  18. Posterior tibial tendoscopy.

    PubMed

    Monteagudo, Manuel; Maceira, Ernesto

    2015-03-01

    The posterior tibial tendon (PTT) helps the triceps surae to work more efficiently during ambulation. Disorders of the PTT include tenosynovitis, acute rupture, degenerative tears, dislocation, instability, enthesopathies, and chronic tendinopathy with dysfunction and flat foot deformity. Open surgery of the PTT has been the conventional approach to deal with these disorders. However, tendoscopy has become a useful technique to diagnose and treat PTT disorders. This article focuses on PTT tendoscopy and tries to provide an understanding of the pathomechanics of the tendon, indications for surgery, surgical technique, advantages, complications, and limitations of this procedure. PMID:25726479

  19. Posterior Cortical Atrophy

    PubMed Central

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

    2013-01-01

    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. PMID:22265212

  20. Posterior Fossa Meningioma

    PubMed Central

    Saleh, Essam A.; Taibah, Abdel Kader; Achilli, Vittorio; Aristegui, Miguel; Mazzoni, Antonio; Sanna, Mario

    1994-01-01

    Posterior fossa meningioma is the second most common tumor in the cerebellopontine angle. It has a higher rate of postoperative morbidity and mortality compared to acoustic neuroma. Forty posterior fossa meningioma patients managed in our centers were reviewed. Thirty-nine patients were managed surgically with 42 surgical procedures. The approaches used were the translabyrinthine approach in 18 patients (43%), the modified transcochlear in 11 cases (26%), the petro-occipital transsigmoid in 5 cases (12%), the suboccipital in 4 cases (10%), the petro-occipital trassigmoid transcervical in 2 cases (5%), the petro-occipital transsigmoid transtentorial in 1 case (2%), and a subtemporal transtentorial for another case (2%). Facial nerve anatomical integrity was preserved in 87% of procedures but was interrupted in 5 cases, with 4 of the latter subsequently repaired. Total tumor removal was accomplished in 38 cases. A second-stage total tumor removal is planned for the remaining case. There was only one case of perioperative death and no cases of radiological recurrence so far. ImagesFigure 1Figure 2Figure 3Figure 4p206-bFigure 5p207-bFigure 5 PMID:17171173

  1. Novel posterior fixation keratoprosthesis

    NASA Astrophysics Data System (ADS)

    Lacombe, Emmanuel

    1992-08-01

    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.

  2. INDICATOR VARIABLE DEPENDENT OUTPUT PROBABILITY MODELLING VIA CONTINUOUS POSTERIOR FUNCTIONS

    E-print Network

    Young, Steve

    with a comparable number of parameters. 1. INTRODUCTION Most HMM-based speech recognition systems use hidden states speaker, the acoustic backgroundcondition and the dynamics of speech like speak- ing rate. This paper by the output pdf's of the hidden states of the HMM. One might think of as a standard feature as used in most

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

    ERIC Educational Resources Information Center

    Satake, Eiki; Amato, Philip P.

    2008-01-01

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

  4. Asteroidal collision probabilities

    NASA Technical Reports Server (NTRS)

    Bottke, William F., Jr.; Greenberg, Richard

    1993-01-01

    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.

  5. Ensemble Particle Filter with Posterior Gaussian By X. Xiong1

    E-print Network

    Ensemble Particle Filter with Posterior Gaussian Resampling By X. Xiong1 and I. M. Navon1 1School March 2005 ABSTRACT An ensemble particle filter(EnPF) was recently developed as a fully nonlinear fil- ter of Bayesian conditional probability estimation, along with the well known ensemble Kalman filter

  6. Posterior Tibial Tendon Dysfunction (PTTD)

    MedlinePLUS

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

  7. Naive Probability: A Mental Model Theory of Extensional Reasoning.

    ERIC Educational Resources Information Center

    Johnson-Laird, P. N.; Legrenzi, Paolo; Girotto, Vittorio; Legrenzi, Maria Sonino; Caverni, Jean-Paul

    1999-01-01

    Outlines a theory of naive probability in which individuals who are unfamiliar with the probability calculus can infer the probabilities of events in an "extensional" way. The theory accommodates reasoning based on numerical premises, and explains how naive reasoners can infer posterior probabilities without relying on Bayes's theorem. (Author/GCP)

  8. IMPROVED log(gf) VALUES FOR LINES OF Ti I AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937 (ACCURATE TRANSITION PROBABILITIES FOR Ti I)

    SciTech Connect

    Lawler, J. E.; Guzman, A.; Wood, M. P.; Sneden, C.; Cowan, J. J. E-mail: adrianaguzman2014@u.northwestern.edu E-mail: chris@verdi.as.utexas.edu

    2013-04-01

    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.

  9. Posterior polar cataract: A review

    PubMed Central

    Kalantan, Hatem

    2011-01-01

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

  10. Posterior polar cataract: A review.

    PubMed

    Kalantan, Hatem

    2012-01-01

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

  11. Bladder neck incompetence at posterior urethroplasty

    PubMed Central

    Koraitim, Mamdouh M.

    2015-01-01

    The finding of an incompetent bladder neck (BN) at the time of posterior urethroplasty will necessarily exacerbate the already difficult situation. In such cases the aim of the treatment is not only to restore urethral continuity by end-to-end urethral anastomosis, but also to restore the function of the BN to maintain urinary continence. Fortunately, the incidence of incompetence of the BN at posterior urethroplasty is uncommon, usually ?4.5%. It seems that pelvic fracture-related BN injuries, in contrast to urethral injuries which result from a shearing force, are due to direct injury by the sharp edge of the fractured and displaced pubic bone. The risk of injuries to the BN is greater in children, in patients with a fracture involving both superior and inferior pubic rami on the same side, and in those managed initially by primary realignment. An incompetent BN is suspected by finding an open rectangular BN on cystography, and a fixedly open BN on suprapubic cystoscopy. An incompetent BN can be treated either subsequent to or concomitant with the urethral repair, according to whether a perineal or a perineo-abdominal urethroplasty is used, respectively. Several options have been reported to treat pelvic fracture-related BN incompetence, including reconstructing the BN, forming a new sphincter by tubularisation of a rectangular flap of the anterior bladder wall, and mechanical occlusion by an artificial sphincter or collagen injection. Reconstruction of the BN by the Young-Dees-Leadbetter?? procedure probably provides the most successful results. PMID:26019982

  12. Robust bayesian sensitivity analysis for case-control studies with uncertain exposure misclassification probabilities.

    PubMed

    Mak, Timothy Shin Heng; Best, Nicky; Rushton, Lesley

    2015-05-01

    Exposure misclassification in case-control studies leads to bias in odds ratio estimates. There has been considerable interest recently to account for misclassification in estimation so as to adjust for bias as well as more accurately quantify uncertainty. These methods require users to elicit suitable values or prior distributions for the misclassification probabilities. In the event where exposure misclassification is highly uncertain, these methods are of limited use, because the resulting posterior uncertainty intervals tend to be too wide to be informative. Posterior inference also becomes very dependent on the subjectively elicited prior distribution. In this paper, we propose an alternative "robust Bayesian" approach, where instead of eliciting prior distributions for the misclassification probabilities, a feasible region is given. The extrema of posterior inference within the region are sought using an inequality constrained optimization algorithm. This method enables sensitivity analyses to be conducted in a useful way as we do not need to restrict all of our unknown parameters to fixed values, but can instead consider ranges of values at a time. PMID:25720128

  13. Intravitreal bevacizumab for posterior capsule neovascularization

    PubMed Central

    Al-Mohaimeed, Mansour; Al-Gehedan, Saeed; Dhibi, Hassan Al

    2010-01-01

    We report a case of rapid regression of extensive posterior capsule neovascularization in a 67-year-old diabetic male patient, who developed posterior capsule opacity with neovascularization one year post cataract surgery, after a single injection of intravitreal bevacizumab (Avastin) followed by neodymium:YAG capsulotomy. Rapid regression of the posterior capsule neovascularization, and visual improvement was observed 9 days after the intervention. Posterior capsulotomy was performed successfully without bleeding. Prior to posterior capsulotomy, intravitreal bevacizumab can result in rapid and dramatic regression of posterior capsule neovascularization. PMID:23960877

  14. Intravitreal bevacizumab for posterior capsule neovascularization.

    PubMed

    Al-Mohaimeed, Mansour; Al-Gehedan, Saeed; Dhibi, Hassan Al

    2010-04-01

    We report a case of rapid regression of extensive posterior capsule neovascularization in a 67-year-old diabetic male patient, who developed posterior capsule opacity with neovascularization one year post cataract surgery, after a single injection of intravitreal bevacizumab (Avastin) followed by neodymium:YAG capsulotomy. Rapid regression of the posterior capsule neovascularization, and visual improvement was observed 9 days after the intervention. Posterior capsulotomy was performed successfully without bleeding. Prior to posterior capsulotomy, intravitreal bevacizumab can result in rapid and dramatic regression of posterior capsule neovascularization. PMID:23960877

  15. Pig Data and Bayesian Inference on Multinomial Probabilities

    ERIC Educational Resources Information Center

    Kern, John C.

    2006-01-01

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

  16. Posterior capsule opacification: experimental analyses.

    PubMed

    Odrich, M G; Hall, S J; Worgul, B V; Trokel, S L; Rini, F J

    1985-01-01

    The lenses of New Zealand White and Flemish Giant rabbits were removed using five techniques representative of the different clinical approaches to extracapsular cataract extraction currently employed. Posterior capsule opacification developed in all experimental animals within 6 weeks of the operation. None of the techniques reduced the incidence of the capsular opacification. Histological analyses including immunofluorescent and tritiated thymidine labelling were used to determine the nature of the cellular constitutents of the secondary membrane. The evidence indicates that the opacity is due not only to lens cells remaining after the operation but also consists of cells of nonlenticular origin. The data strongly implicate the anterior uvea as the source of those cells. Furthermore, the findings suggest that posterior capsule opacification is the product of a migration and a proliferation of both cell populations. PMID:3885127

  17. Distortions of posterior visual space.

    PubMed

    Phillips, Flip; Voshell, Martin G

    2009-01-01

    The study of spatial vision is a long and well traveled road (which, of course, converges to a vanishing point at the horizon). Its various distortions have been widely investigated empirically, and most concentrate, pragmatically, on the space anterior to the observer. The visual world behind the observer has received relatively less attention and it is this perspective the current experiments address. Our results show systematic perceptual distortions in the posterior visual world when viewed statically. Under static viewing conditions, observer's perceptual representation was consistently 'spread' in a hyperbolic fashion. Directions to distant, peripheral locations were consistently overestimated by about 11 degrees from the ground truth and this variability increased as the target was moved toward the center of the observer's back. The perceptual representation of posterior visual space is, no doubt, secondary to the more immediate needs of the anterior visual world. Still, it is important in some domains including certain sports, such as rowing, and in vehicular navigation. PMID:19764306

  18. Confidence Probability versus Detection Probability

    SciTech Connect

    Axelrod, M

    2005-08-18

    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.

  19. CO2 laser posterior transverse cordotomy for isolated type IV posterior glottic stenosis.

    PubMed

    Gaboriau, H; Laccourreye, O; Laccourreye, H; Brasnu, D

    1995-01-01

    One case of isolated type IV posterior glottic stenosis successfully treated with CO2 laser posterior transverse cordotomy is presented. This report emphasized the value of the CO2 laser posterior transverse cordotomy in this situation. A review of the various therapeutic options advocated in the medical literature to treat isolated posterior glottic stenosis is also presented. PMID:7503381

  20. Updating Probabilities

    E-print Network

    Caticha, A; Caticha, Ariel; Giffin, Adom

    2006-01-01

    We show that Skilling's method of induction leads to a unique general theory of inductive inference, the method of Maximum relative Entropy (ME). The main tool for updating probabilities is the logarithmic relative entropy; other entropies such as those of Renyi or Tsallis are ruled out. We also show that Bayes updating is a special case of ME updating and thus, that the two are completely compatible.

  1. probability distributions

    E-print Network

    Heller, Barbara

    probabilities in the standard normal table What is the area to the left of Z=1.51 in a standard normal curve? Z=1.51 Z=1.51 Area is 93.45% #12;Exercises · If scores are normally distributed with a mean of 30 beauty of the normal curve: No matter what and are, the area between - and + is about 68%; the area

  2. BAYESIAN MULTIPLE PERSON TRACKING USING PROBABILITY

    E-print Network

    Frean, Marcus

    BAYESIAN MULTIPLE PERSON TRACKING USING PROBABILITY HYPOTHESIS DENSITY SMOOTHING S. Hernandez or multiple cameras, the scope and availability of multiple target tracking techniques for crowd analysis has approximation to the posterior density. The PHD filter is a good alternative to standard multi-target tracking

  3. Longevity of Posterior Composite Restorations

    PubMed Central

    Opdam, N.J.M.; van de Sande, F.H.; Bronkhorst, E.; Cenci, M.S.; Bottenberg, P.; Pallesen, U.; Gaengler, P.; Lindberg, A.; Huysmans, M.C.D.N.J.M.; van Dijken, J.W.

    2014-01-01

    The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years’ follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. PMID:25048250

  4. Negative probability

    E-print Network

    Andreas Blass; Yuri Gurevich

    2015-02-02

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

  5. The Non-Gaussian Sting in Posteriors arising from Marginal Detections

    E-print Network

    Bassett, Bruce A

    2010-01-01

    We show that in cases of marginal detections (~ 3 sigma), such as of Baryonic Acoustic Oscillations in cosmology, the full posterior probability for parameters is significantly non-Gaussian, due to the transition from the likelihood to the prior. This sting in the tail of the distribution radically alters confidence intervals on parameters and means that one cannot naively extrapolate 1-sigma error bars to 3-sigma and beyond as is typically done. We propose a simple formula which corrects for this effect in posterior probabilities arising from marginal detections.

  6. A Review of Lesions of the Posterior Fourchette, Posterior Vestibule (Fossa Navicularis), and Hymen.

    PubMed

    Heller, Debra S

    2015-07-01

    Lesions specific to the posterior fourchette, posterior vestibule (fossa navicularis), and hymen are reviewed. Knowledge of these regional lesions will be helpful if such a patient is encountered. PMID:25943866

  7. Secondary closure of posterior continuous circular capsulorhexis.

    PubMed

    Tassignon, M J; De Groot, V; Smets, R M; Tawab, B; Vervecken, F

    1996-01-01

    We examined the hypothesis that removing the center of the posterior capsule would reduce the risk for posterior opacification (PCO). We considered the prevalence of post-operative complications after PCCC like retinal detachment and cystoid macular edema, as found after Nd-YAG laser capsulotomy. PMID:9009367

  8. Posterior capsule staining and posterior continuous curvilinear capsulorhexis in congenital cataract.

    PubMed

    Wakabayashi, Taketoshi; Yamamoto, Narumichi

    2002-11-01

    We report 2 cases of indocyanine green (ICG) staining used for posterior continuous curvilinear capsulorhexis (PCCC) in congenital cataract combined with anterior vitrectomy. In the first case, because of corneal opacity, the visibility of the posterior capsule was poor without staining. After the extraction of the cataract, a PCCC was performed after ICG staining of the posterior capsule. In the second case, after cataract removal, ICG staining was used to better visualize the posterior capsule. In both cases, the PCCC was successfully completed because of better visualization of the stained posterior capsule flap against the transparent anterior hyaloid face of the vitreous. Clear visual axes have been maintained. PMID:12457683

  9. Adaptive approximation of higher order posterior statistics

    SciTech Connect

    Lee, Wonjung

    2014-02-01

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

  10. HOW PROBABILITIES REFLECT EVIDENCE James M. Joyce

    E-print Network

    Fitelson, Branden

    . This is what individual probability values reflect. The weight of the evidence is a matter of the gross amount of accurately representing the distinctions between the balance, weight and specificity of evidence, and (ii

  11. Multinomial mixture model with heterogeneous classification probabilities

    USGS Publications Warehouse

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

    2011-01-01

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

  12. Congenital Hairy Polyp of Posterior Tonsillar Pillar

    PubMed Central

    Iqbal, Shahid; Talat, Nabila; Saleem, Muhammad

    2014-01-01

    Congenital hairy polyps are exceedingly rare congenital anomalies. We report a case of congenital hairy polyp arising from posterior tonsillar pillar which was excised with bipolar cautry. PMID:26023478

  13. Posterior Hip Pain in an Athletic Population

    PubMed Central

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

    2010-01-01

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

  14. Meibomian Gland Dysfunction and Treatment (Posterior Blepharitis)

    MedlinePLUS

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

  15. 14 CFR 417.224 - Probability of failure analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  16. 14 CFR 417.224 - Probability of failure analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  17. 14 CFR 417.224 - Probability of failure analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  18. 14 CFR 417.224 - Probability of failure analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  19. 14 CFR 417.224 - Probability of failure analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  20. An unusual cause of posterior mediastinal cyst

    PubMed Central

    Dhooria, Sahajal; Muthu, Valliappan; Agarwal, Ritesh

    2015-01-01

    Cystic lesions of the mediastinum may be congenital or acquired. The differential diagnosis depends on their location in the mediastinum. Cysts in the posterior mediastinum are generally developmental cysts and are neurogenic or of foregut origin. We report the case of a 14-year-old boy, who presented with dry cough and progressively increasing breathlessness, and was found to have a cystic lesion in the posterior mediastinum. Fine needle aspiration from the cyst helped make a diagnosis of tuberculosis.

  1. Posterior Shoulder Instability in Overhead Athletes.

    PubMed

    Chang, Edward S; Greco, Nicholas J; McClincy, Michael P; Bradley, James P

    2016-01-01

    Posterior shoulder instability in overhead athletes presents a unique and difficult challenge. Often, this group has an inherent capsular laxity and/or humeral retroversion to accommodate the range of motion necessary to throw. This adaptation makes the diagnosis of posterior capsulolabral pathology challenging, as the examiner must differentiate between adaptive capsular laxity and pathologic instability. Further complicating matters, the intraoperative surgeon must find the delicate balance of achieving stability while still allowing the necessary range of motion. PMID:26614932

  2. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

    PubMed

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A ?catenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (?catenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  3. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    PubMed Central

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A ?catenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (?catenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  4. Bayesian methods for Support Vector Machines: Evidence and predictive class probabilities

    E-print Network

    Sollich, Peter

    Bayesian methods for Support Vector Machines: Evidence and predictive class probabilities Peter.sollich@kcl.ac.uk Abstract. I describe a framework for interpreting Support Vector Machines (SVMs) as maximum a posteriori simple evaluation at the MAP or at the posterior average to full averaging over the posterior. A simple

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

    E-print Network

    Delp, Scott

    the prosthesis. Passively flexing and extending the knee, we calculated anterior femoral translationPosterior Cruciate Ligament Removal Contributes to Abnormal Knee Motion during Posterior Stabilized Total Knee Arthroplasty Melinda J. Cromie,1,2 Robert A. Siston,1,2,3,4 Nicholas J. Giori,2,5 Scott L

  6. Incidence of posterior capsule opacification in eyes with and without posterior chamber intraocular lenses.

    PubMed

    Nishi, O

    1986-09-01

    The incidence of posterior capsule opacification after extracapsular cataract extraction was significantly lower in eyes implanted with posterior chamber intraocular lenses than in nonimplanted eyes. The number of loops fixated in the bag was significantly smaller in the eyes that became opacified than in those that did not. These findings suggest that the posterior chamber lens suppresses the two processes that lead to opacification: the development of a ring-shaped opacity at the site of contact between the anterior capsule rim and the posterior capsule and the migration of lens epithelial cells toward the center of the capsule. These suppressive effects were greater when the posterior chamber lens was fixated in the bag. PMID:3772787

  7. On differentiating the probability of error in multipopular feature selection

    NASA Technical Reports Server (NTRS)

    Peters, B. C.

    1974-01-01

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

  8. Posterior predictive checking of multiple imputation models.

    PubMed

    Nguyen, Cattram D; Lee, Katherine J; Carlin, John B

    2015-07-01

    Multiple imputation is gaining popularity as a strategy for handling missing data, but there is a scarcity of tools for checking imputation models, a critical step in model fitting. Posterior predictive checking (PPC) has been recommended as an imputation diagnostic. PPC involves simulating "replicated" data from the posterior predictive distribution of the model under scrutiny. Model fit is assessed by examining whether the analysis from the observed data appears typical of results obtained from the replicates produced by the model. A proposed diagnostic measure is the posterior predictive "p-value", an extreme value of which (i.e., a value close to 0 or 1) suggests a misfit between the model and the data. The aim of this study was to evaluate the performance of the posterior predictive p-value as an imputation diagnostic. Using simulation methods, we deliberately misspecified imputation models to determine whether posterior predictive p-values were effective in identifying these problems. When estimating the regression parameter of interest, we found that more extreme p-values were associated with poorer imputation model performance, although the results highlighted that traditional thresholds for classical p-values do not apply in this context. A shortcoming of the PPC method was its reduced ability to detect misspecified models with increasing amounts of missing data. Despite the limitations of posterior predictive p-values, they appear to have a valuable place in the imputer's toolkit. In addition to automated checking using p-values, we recommend imputers perform graphical checks and examine other summaries of the test quantity distribution. PMID:25939490

  9. Large posterior abdominal masses: computed tomographic localization

    SciTech Connect

    Engel, I.A.; Auh, Y.H.; Rubenstein, W.A.; Whalen, J.P.; Kazam, E.

    1983-10-01

    Large posterior abdominal masses, particularly those in the right upper abdomen, may be difficult to localize correctly into the peritoneal or retroperitoneal compartments. The following signs were found to be reliable CT indicators of retroperitoneal location: obliteration of the perinephric fat outlining the psoas muscle; lateral displacement of the fat outlining the posterior right lobe of the liver; rotation of the intrahepatic portal veins to the left; anterior displacement of the inferior vena cava and renal veins; and anterior displacement of the ascending colon, descending duodenum, or pancreatic head.

  10. Imaging the posterior mediastinum: a multimodality approach

    PubMed Central

    Occhipinti, Mariaelena; Heidinger, Benedikt H.; Franquet, Elisa; Eisenberg, Ronald L.; Bankier, Alexander A.

    2015-01-01

    The posterior mediastinum contains several structures that can produce a wide variety of pathologic conditions. Descending thoracic aorta, esophagus, azygos and hemiazygos veins, thoracic duct, lymph nodes, adipose tissue, and nerves are all located in this anatomical region and can produce diverse abnormalities. Although chest radiography may detect many of these pathologic conditions, computed tomography and magnetic resonance are the imaging modalities of choice for further defining the relationship of posterior mediastinal lesions to neighboring structures and showing specific imaging features that narrow the differential diagnosis. This review emphasizes modality-related answers to morphologic questions, which provide precise diagnostic information. PMID:25993732

  11. Probability 1/e

    ERIC Educational Resources Information Center

    Koo, Reginald; Jones, Martin L.

    2011-01-01

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

  12. How Accurate is Psychiatry?

    ERIC Educational Resources Information Center

    Greenburg, Joel

    1977-01-01

    The problems that plague psychiatry; such as poor diagnoses, inappropriate treatment, and outdated resources are detailed. A new, more accurate, Diagnostic and Statistical Manual of Mental Disorders (DSM III) to be adopted in 1978 may alleviate many improper diagnoses and treatments. (BT)

  13. Posterior instability caused by batter's shoulder.

    PubMed

    Kang, Richard W; Mahony, Gregory T; Harris, Thomas C; Dines, Joshua S

    2013-10-01

    In summary, batter’s shoulder is a rare and only recently recognized entity. This condition is posterior shoulder instability caused by a missed attempt at hitting a pitch, especially with an outside pitch. The lack of counterforce from hitting a ball produces increased forces imparted on the posterior capsulolabral complex of the lead shoulder during batting. If the player fails conservative management, she or he can undergo an arthroscopic posterior labral repair instead of debridement. After treatment, the player can expect to return to play after approximately 6 to 7 months. Initial results from a small, retrospective series demonstrate greater than 90% excellent results. These findings are similar to current literature for arthroscopic treatment of posterior instability, which reports success rates that range from 75% to 91%. Longer-term follow-up will be needed to determine the natural history and prognosis or batter’s shoulder. Based on initial results, the authors predict good to excellent results for most players with batter’s shoulder who undergo proper treatment. Additionally, with the exception of switch hitters, the nonthrowing arm is affected. This can also improve the athlete’s return to play. PMID:24079435

  14. BAER suppression during posterior fossa dural opening

    PubMed Central

    Shields, Christopher B.; Shields, Lisa B. E.; Jiang, Yi Dan; Yao, Tom; Zhang, Yi Ping; Sun, David A.

    2015-01-01

    Background: Intraoperative monitoring with brainstem auditory evoked responses (BAER) provides an early warning signal of potential neurological injury and may avert tissue damage to the auditory pathway or brainstem. Unexplained loss of the BAER signal in the operating room may present a dilemma to the neurosurgeon. Methods: This paper documents two patients who displayed a unique mechanism of suppression of the BAER apparent within minutes following dural opening for resection of a posterior fossa meningioma. Results: In two patients with anterior cerebellopontine angle and clival meningiomas, there was a significant deterioration of the BAER soon after durotomy but prior to cerebellar retraction and tumor removal. Intracranial structures in the posterior fossa lying between the tumor and dural opening were shifted posteriorly after durotomy. Conclusion: We hypothesized that the cochlear nerve and vessels entering the acoustic meatus were compressed or stretched when subjected to tissue shift. This movement caused cochlear nerve dysfunction that resulted in BAER suppression. BAER was partially restored after the tumor was decompressed, dura repaired, and bone replaced. BAER was not suppressed following durotomy for removal of a meningioma lying posterior to the cochlear complex. Insight into the mechanisms of durotomy-induced BAER inhibition would allay the neurosurgeon's anxiety during the operation. PMID:25883849

  15. [Posterior capsule opacification after extracapsular extraction with a posterior chamber implant].

    PubMed

    Teodoru, A

    1996-01-01

    The opacity of posterior capsule after the extracapsular extraction of the crystalline with implant of an artificial crystalline in the posterior chamber is a post-operatory complication which is meeting in 5.33% operated eyes with a subjective consequence which is a visual acuity diminuation with the appearance of some bright bands in the visual field of the operated eyes especially in the night. The principal reasons was founded to be the patient age and the disposal of pseudophakia in the ciliary sulcus what is permitting the contact of the anterior chamber's remains with the posterior capsule which is the place of beginning to the epithelium proliferation. PMID:8962855

  16. Accurate Finite Difference Algorithms

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    1996-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Harrison, Diana; Sutton, David; Carvalho, Pedro; Hobson, Michael

    2015-08-01

    We extend the Kolmogorov-Smirnov (K-S) test to multiple dimensions by suggesting a R^n ? [0,1] mapping based on the probability content of the highest probability density region of the reference distribution under consideration; this mapping reduces the problem back to the one-dimensional case to which the standard K-S test may be applied. The universal character of this mapping also allows us to introduce a simple, yet general, method for the validation of Bayesian posterior distributions of any dimensionality. This new approach goes beyond validating software implementations; it provides a sensitive test for all assumptions, explicit or implicit, that underlie the inference. In particular, the method assesses whether the inferred posterior distribution is a truthful representation of the actual constraints on the model parameters. We illustrate our multidimensional K-S test by applying it to a simple two-dimensional Gaussian toy problem, and demonstrate our method for posterior validation in the real-world astrophysical application of estimating the physical parameters of galaxy clusters parameters from their Sunyaev-Zel'dovich effect in microwave background data. In the latter example, we show that the method can validate the entire Bayesian inference process across a varied population of objects for which the derived posteriors are different in each case.

  18. Probability Calculus Bayesian Networks

    E-print Network

    Huang, Jinbo

    Probability Calculus Bayesian Networks Logic and Bayesian Networks Part 1: Probability Calculus and Bayesian Networks Jinbo Huang Jinbo Huang Probability Calculus and Bayesian Networks 1/ 31 #12;Probability Calculus Bayesian Networks What This Course Is About Probabilistic reasoning with Bayesian networks

  19. Probability Primer 1 Running head: PROBABILITY PRIMER

    E-print Network

    Yuille, Alan L.

    inference, bio-informatics, and computer vision. Applying probabilistic models to human cognition thus Probabilistic models aim to explain human cognition by appealing to the principles of probability theory structured probability distributions, introducing some of the key ideas behind graphical models, which can

  20. On Probability Domains III

    NASA Astrophysics Data System (ADS)

    Fri?, Roman; Pap?o, Martin

    2015-12-01

    Domains of generalized probability have been introduced in order to provide a general construction of random events, observables and states. It is based on the notion of a cogenerator and the properties of product. We continue our previous study and show how some other quantum structures fit our categorical approach. We discuss how various epireflections implicitly used in the classical probability theory are related to the transition to fuzzy probability theory and describe the latter probability theory as a genuine categorical extension of the former. We show that the IF-probability can be studied via the fuzzy probability theory. We outline a "tensor modification" of the fuzzy probability theory.

  1. Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: a meta-analysis.

    PubMed

    Bercik, Michael J; Joshi, Ashish; Parvizi, Javad

    2013-03-01

    The objective of this meta-analysis was to compare outcomes of posterior cruciate-retaining and posterior stabilized prostheses. A computerized literature search was conducted to identify randomized controlled trials comparing the clinical outcomes of cruciate-retaining and posterior-stabilized designs. The table of contents of four major Orthopaedic journals and the references section of two arthroplasty text books were reviewed to identify other relevant studies. Ultimately, 1114 patients (1265 knees) were compared. Statistical analysis revealed a significant difference in flexion and range of motion in favor of posterior-stabilized knees, but no difference in complication rates. The clinical importance of this remains unknown. The decision to use one design versus the other should rest with the surgeon's preference and comfort with a particular design. PMID:23433255

  2. Hypertensive posterior reversible encephalopathy syndrome causing posterior fossa edema and hydrocephalus.

    PubMed

    Grossbach, Andrew J; Abel, Taylor J; Hodis, Brendan; Wassef, Shafik N; Greenlee, Jeremy D W

    2014-02-01

    Posterior reversible encephalopathy syndrome (PRES) is a well characterized entity resulting from the inability of cerebral autoregulation to adequately protect the brain from uncontrolled hypertension. It primarily affects the occipital lobes, but can also involve the structures in the posterior fossa including the brainstem and cerebellum. Treatment usually consists of strict blood pressure control, but more aggressive management may be indicated with acutely worsening neurological status. We present a patient with hypertensive encephalopathy that resulted in hydrocephalus and brainstem compression necessitating surgical decompression requiring ventriculostomy and suboccipital craniectomy. In rare cases, PRES can present with severe brainstem compression requiring emergent posterior fossa decompression. When brainstem signs are present on exam, emergent posterior fossa decompression may be safer than ventriculostomy alone. PMID:24126039

  3. An Unusual Cause of Posterior Elbow Impingement: Detachment of a Hypertrophied Posterior Fat Pad

    PubMed Central

    Hamada, Daisuke; Matsuura, Tetsuya; Sugiura, Kosuke; Higuchi, Tadahiro; Suzue, Naoto; Goto, Tomohiro; Tsutsui, Takahiko; Wada, Keizo; Fukuta, Shoji; Sairyo, Koichi

    2015-01-01

    We report a case of a 47-year-old woman who developed posterior impingement of the elbow due to detachment of a hypertrophied posterior fat pad. She reported acute left elbow pain after leaning back onto a hard object with her hand and subsequently experienced a “catching” sensation. Comparison with the magnetic resonance images of a normal elbow revealed a hypertrophied posterior fat pad interposed between the olecranon and olecranon fossa in both elbows, with the fat pad in the left elbow located more inferiorly than that in the right elbow. Elbow arthroscopy showed the olecranon fossa covered by the fat pad, a portion of which was detached from the rest of the pad. Debridement of the detached portion was performed until no impingement was evident. Postoperatively, full extension of the elbow did not elicit pain. Clinicians should include this pathology among the differential diagnoses for posterior elbow pain. PMID:26613057

  4. A Cadaveric Study of Bilateral Configuration of Posterior Bifurcation of Posterior Communicating Artery in Indian Population

    PubMed Central

    Saha, Anubha; Mandal, Shyamash

    2015-01-01

    Introduction: Various studies have been done regarding variations of circle of Willis, but few literatures are available about the detail configurations on Indian population. Posterior communicating artery is the main collateral channel between the vertebrobasilar and carotid system. It may act as a main source of blood flow via posterior cerebral artery if fetal configuration is present. Aim of the study is to see the bilateral configurations to compare the blood supply of both cerebral hemispheres via posterior cerebral artery in human cadavers. Materials and Methods: Fifty six formalin fixed brains were used for study. The specimens were classified into 3 types and 21 subtypes according to the configuration of the vessel of both hemispheres. As hemodynamic balance is dependent on the calibre of the vessel, the diameter of the arteries were also taken into consideration. Pearson’s correlation had been done. Result: In present study type I is 57.2%, type II is 37.5% and type III is 5.4%. Incidence of unilateral fetal type posterior cerebral artery is in high percentage (33.9%). Greatest diameter of posterior communicating artery is 3.8mm on right and 3.6mm on left side. Significant correlations also have been found between arterial segments of different types. Conclusion: It is expected that the study will help to enrich the knowledge about the arterial predominance of origin of posterior cerebral artery of both cerebral hemispheres in normal or variant cases and its effect on perfusion images. PMID:25954608

  5. Posterior Pole Sparing Laser Photocoagulation Combined with Intravitreal Bevacizumab Injection in Posterior Retinopathy of Prematurity

    PubMed Central

    Kim, Rebecca; Kim, Yu Cheol

    2014-01-01

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

  6. Sm Transition Probabilities and Abundances

    E-print Network

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

    2005-10-19

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

  7. Autonomic dysreflexia and posterior reversible encephalopathy syndrome.

    PubMed

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

    2013-05-01

    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

  8. Flood hazard probability mapping method

    NASA Astrophysics Data System (ADS)

    Kalantari, Zahra; Lyon, Steve; Folkeson, Lennart

    2015-04-01

    In Sweden, spatially explicit approaches have been applied in various disciplines such as landslide modelling based on soil type data and flood risk modelling for large rivers. Regarding flood mapping, most previous studies have focused on complex hydrological modelling on a small scale whereas just a few studies have used a robust GIS-based approach integrating most physical catchment descriptor (PCD) aspects on a larger scale. The aim of the present study was to develop methodology for predicting the spatial probability of flooding on a general large scale. Factors such as topography, land use, soil data and other PCDs were analysed in terms of their relative importance for flood generation. The specific objective was to test the methodology using statistical methods to identify factors having a significant role on controlling flooding. A second objective was to generate an index quantifying flood probability value for each cell, based on different weighted factors, in order to provide a more accurate analysis of potential high flood hazards than can be obtained using just a single variable. The ability of indicator covariance to capture flooding probability was determined for different watersheds in central Sweden. Using data from this initial investigation, a method to subtract spatial data for multiple catchments and to produce soft data for statistical analysis was developed. It allowed flood probability to be predicted from spatially sparse data without compromising the significant hydrological features on the landscape. By using PCD data, realistic representations of high probability flood regions was made, despite the magnitude of rain events. This in turn allowed objective quantification of the probability of floods at the field scale for future model development and watershed management.

  9. Probability and Relative Frequency

    NASA Astrophysics Data System (ADS)

    Drieschner, Michael

    2015-10-01

    The concept of probability seems to have been inexplicable since its invention in the seventeenth century. In its use in science, probability is closely related with relative frequency. So the task seems to be interpreting that relation. In this paper, we start with predicted relative frequency and show that its structure is the same as that of probability. I propose to call that the `prediction interpretation' of probability. The consequences of that definition are discussed. The "ladder"-structure of the probability calculus is analyzed. The expectation of the relative frequency is shown to be equal to the predicted relative frequency. Probability is shown to be the most general empirically testable prediction.

  10. Intraneural neurofibromas involving the posterior interosseous nerve

    PubMed Central

    Lallemand, R. C.; Weller, R. O.

    1973-01-01

    Two patients presented with a posterior interosseous nerve palsy with supinator weakness. In each case an intraneural neurofibroma was found proximal to the supinator tunnel with no other stigmata of von Recklinghausen's disease. Both tumours showed a whorl-like histological pattern that has been previously confused with onion-bulb structures in hypertrophic polyneuropathy. Electron-microscopy was useful for the pathological diagnosis. The prognosis and treatment of the lesions are discussed. Images PMID:4772730

  11. Posterior capsular contracture of the shoulder.

    PubMed

    Bach, H Gregory; Goldberg, Benjamin A

    2006-05-01

    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

  12. The diagnostic dilemma of the posterior mediastinal thymus: CT manifestations

    SciTech Connect

    Cohen, M.D.; Weber, T.R.; Sequeira, F.W.; Vane, D.W.; King, H.

    1983-03-01

    Extension of the normal thymus into the posterior mediastinum is rare. The CT appearance of this anomaly in an infant is presented. A mass of soft-tissue density extended from the anterior mediastinum to the posterior chest wall. The absence of any tissue-cleavage plane in the lesion and a smooth continuous lateral margin are signs of posterior extension of the thymus, and they help to distinguish this from a normal anterior thymus being present with a posterior tumor.

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

    SciTech Connect

    Rich, M.W.; Imburgia, M.; King, T.R.; Fischer, K.C.; Kovach, K.L. )

    1989-09-01

    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.

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

    E-print Network

    Chastain, Pepper Alise

    1996-01-01

    breed groups of E. caballus were compared for calculation of population differentiation and genetic distance using three different distance estimates, Ds, Dps and Ddm. The draft-origin breed group showed the greatest allelic diversity with an average...

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

    E-print Network

    Pokta, Suriani

    2004-11-15

    and encouragement throughout the years. I would also like to extend my thanks to Drs. Calvin, Chen, Claeskens, Cline, Dahm, Fan, Longnecker, Spiegelman, Vannucci and Wehrly for their generosity and understanding. Lastly, I wish to thank Veera Baladandayuthapani... variables with mean 0 and finite variance. The epsilon1j?s are allowed to be heteroscedastic in the following manner: Var(epsilon1j) = exp(2(beta0 + beta1j)), j = 1,...,n. The justification for this model is that an earlier analysis indicated a tendency...

  16. P-values, q-values and posterior probabilities for equivalence in genomics studies

    E-print Network

    Solomon, Patty

    studies, as illustrated by the following. Illustration 1: Gene profiling. There are biological problems, and analyse data from a mouse stem cell microarray experiment which demonstrate the theory and methods according to their conformance to a pre-specified profile of expression over time, known as gene profiling

  17. 130 IEEE TRANSACTIONS ON NEURAL NETWORKS, VOL. 19, NO. 1, JANUARY 2008 Multiclass Posterior Probability

    E-print Network

    Alpaydýn, Ethem

    November 17, 2006; revised March 26, 2007; ac- cepted May 1, 2007. This work was supported by the Turkish-1-1, the Bogaziçi University Scientific Research Project 05HA101, and the Turkish Scientific Technical Research if , and choose the negative class if . This model is generalized to learn nonlinear discriminants by using kernel

  18. Computing Posterior Probabilities for Score-based Alignments Using ppALIGN

    E-print Network

    Peinke, Joachim

    -score or low-complexity regions, a huge number of alternative alignments arise which results in a decrease to compute position-wise reliability of score-based pairwise alignments of DNA or protein sequences-line computations. We have also included alternative decoding algorithms to provide alternative alignments. pp

  19. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    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.

  20. Dependent Probability Spaces

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  1. Dynamical Simulation of Probabilities

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1996-01-01

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

  2. A categorical foundation for Bayesian probability

    E-print Network

    Culbertson, Jared

    2012-01-01

    Given two measurable spaces $H$ and $D$ with countably generated $\\sigma$-algebras, a prior probability measure $P_H$ on $H$ and a sampling distribution $\\mcS:H \\rightarrow D$, there is a corresponding inference map $\\mcI:D \\rightarrow H$ which is unique up to a set of measure zero. Thus, given a data measurement $\\mu:1 \\rightarrow D$, a posterior probability $\\hat{P_H}=\\mcI \\circ \\mu$ can be computed. This procedure is iterative: with each updated probability $P_H$, we obtain a new joint distribution which in turn yields a new inference map $\\mcI$ and the process repeats with each additional measurement. The main result shows that the assumption of Polish spaces to obtain regular conditional probabilities is not necessary---countably generated spaces suffice. This less stringent condition then allows for non-trivial decision rules (Eilenberg--Moore algebras) on finite (as well as non finite) spaces, and also provides for a common framework for decision theory and Bayesian probability.

  3. Anterior and posterior fixation for delayed treatment of posterior atlantoaxial dislocation without fracture.

    PubMed

    Yu, Hai Ming; Malhotra, Karan; Butler, Joseph S; Wu, Shi Qiang

    2015-01-01

    Posterior atlantoaxial dislocation (PAAD) without fracture of the odontoid process is a rare injury. Authors have variously reported closed or open reduction, followed by either anterior or posterior fixation, but there is no consensus on best treatment. We present a particularly unstable case of PAAD. Open reduction through a retropharyngeal approach with odontoidectomy was required for reduction. Anterior fixation with transarticular lag screws was required prior to posterior fixation with pedicle screws. Despite non-compliance with postoperative immobilisation, imaging at 20-month follow-up confirmed solid fusion. The patient is pain-free with a good range of movement of the neck and has returned to a manual job. Our case had a greater degree of instability than was previously reported, which necessitated 360° fixation. This is the first reported case of this treatment strategy, which provided a very stable fixation allowing fusion despite early movement and without causing undue stiffness. PMID:26516249

  4. Diagnostic imaging of posterior fossa anomalies in the fetus and neonate: part 2, Posterior fossa disorders.

    PubMed

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

    2015-01-01

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

  5. Complications when augmenting the posterior maxilla.

    PubMed

    Fugazzotto, Paul; Melnick, Philip R; Al-Sabbagh, Mohanad

    2015-01-01

    The maxillary posterior edentulous region presents a challenge when planning for restoring missing teeth with a dental implant. The available bone in such cases is often not dense and not adequate for the placement of a properly sized implant because of maxillary sinus pneumatization and alveolar bone loss. Maxillary sinus lift is a predictable procedure to provide adequate bone height for the purpose of implant placement. However, complications are encountered during or after the execution of the sinus lift procedure. In this article, the prevention and management of maxillary sinus complications are discussed. PMID:25434561

  6. Posterior shoulder instability in the contact athlete.

    PubMed

    Tannenbaum, Eric P; Sekiya, Jon K

    2013-10-01

    Historically, posterior shoulder instability has been a challenging problem for contact athletes and orthopedic surgeons alike. A complete understanding of the normal shoulder anatomy and biomechanics and the pathoanatomy responsible for the instability is necessary for a successful clinical outcome. In addition, the surgeon must be familiar with the diagnostic imaging and physical examination maneuvers required for the correct diagnosis without missing any other concurrent abnormalities. This understanding will allow orthopedists to plan and execute the appropriate management, whether this may involve conservative or surgical intervention. The goal should always be to correct the abnormality and have the patient return to play with full strength and no recurrent instability. PMID:24079434

  7. Posterior consistency in conditional distribution estimation

    PubMed Central

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

    2014-01-01

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

  8. Experimental models for posterior capsule opacification research.

    PubMed

    Wormstone, Ian Michael; Eldred, Julie Ann

    2016-01-01

    Millions of people worldwide are blinded due to cataract formation. At present the only means of treating a cataract is through surgical intervention. A modern cataract operation involves the creation of an opening in the anterior lens capsule to allow access to the fibre cells, which are then removed. This leaves in place a capsular bag that comprises the remaining anterior capsule and the entire posterior capsule. In most cases, an intraocular lens is implanted into the capsular bag during surgery. This procedure initially generates good visual restoration, but unfortunately, residual lens epithelial cells undergo a wound-healing response invoked by surgery, which in time commonly results in a secondary loss of vision. This condition is known as posterior capsule opacification (PCO) and exhibits classical features of fibrosis, including hyperproliferation, migration, matrix deposition, matrix contraction and transdifferentiation into myofibroblasts. These changes alone can cause visual deterioration, but in a significant number of cases, fibre differentiation is also observed, which gives rise to Soemmering's ring and Elschnig's pearl formation. Elucidating the regulatory factors that govern these events is fundamental in the drive to develop future strategies to prevent or delay visual deterioration resulting from PCO. A range of experimental platforms are available for the study of PCO that range from in vivo animal models to in vitro human cell and tissue culture models. In the current review, we will highlight some of the experimental models used in PCO research and provide examples of key findings that have resulted from these approaches. PMID:25939555

  9. Posterior surgical approaches to the rectum.

    PubMed

    Westbrook, K C; Lang, N P; Broadwater, J R; Thompson, B W

    1982-06-01

    This report summarizes experience with 19 posterior approaches to the rectum including nine trans-sacral (Kraske) and ten trans-sphincteric (Mason) procedures. This study included 12 men and 7 women, ranging in age from 18 to 89 years. Surgical indications included villous tumors in nine patients, various benign problems in four patients, primary carcinomas in three patients, and recurrent cancer in three patients. Eight complications developed in the 19 patients including: four fecal fistulae, two wound dehiscences, one rectal stricture, and one sacrococcygeal hernia. Spontaneous closure of the fecal fistulae occurred in two patients, and two patients required proximal colostomies. Fecal continence was achieved in 18 of the 19 patients. No patient died as a complication of the procedure. No recurrent tumors have developed. The conclusion is that a posterior approach to the rectum is a safe and effective procedure for various benign and for selected malignant conditions. It is particularly suitable for villous tumors that are too high for transanal resection and too low for transabdominal resection. It is an effective procedure for small, exophytic, mobile carcinomas of the lower 10 cm of the rectum in selected patients. PMID:7082059

  10. Posterior malleolar fractures of the ankle.

    PubMed

    Bartoní?ek, J; Rammelt, S; Tu?ek, M; Na?ka, O

    2015-12-01

    Despite an increasing awareness of injuries to PM in ankle fracture-dislocations, there are still many open questions. The mere presence of a posterior fragment leads to significantly poorer outcomes. Adequate diagnosis, classification and treatment require preoperative CT examination, preferably with 3D reconstructions. The indication for surgical treatment is made individually on the basis of comprehensive assessment of the three-dimensional outline of the PM fracture and all associated injuries to the ankle including syndesmotic instability. Anatomic fixation of the avulsed posterior tibiofibular ligament will contribute to syndesmotic stability and restore the integrity of the incisura tibiae thus facilitating anatomic reduction of the distal fibula. A necessary prerequisite is mastering of posterolateral and posteromedial approaches and the technique of direct reduction and internal fixation. Further clinical studies with higher numbers of patients treated by similar methods and evaluation of pre- and postoperative CT scans will be necessary to determine reliable prognostic factors associated with certain types of PM fractures and associated injuries to the ankle. PMID:26253884

  11. Potential acuity meter for predicting visual acuity after Nd:YAG posterior capsulotomy

    SciTech Connect

    Smiddy, W.E.; Radulovic, D.; Yeo, J.H.; Stark, W.J.; Maumenee, A.E.

    1986-03-01

    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.

  12. Posterior cortical atrophy: visuomotor deficits in reaching and grasping

    PubMed Central

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

    2013-01-01

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

  13. [Is posterior lumbar epidural space partitioned?].

    PubMed

    Morisot, P

    1992-01-01

    The anatomy of the posterior lumbar epidural space (PLES) has been extensively studied. Besides the anatomists, surgeons, radiologists and anaesthetists have taken an interest in this. However, because each one has considered the PLES from his own specialist field, descriptions are not always concordant. In particular, the reality of a medial partition in the PLES has been suggested by epidurography and intraoperative observations. Lewit and Sereghy and Luyendijk opened the debate by reporting, on antero-posterior epidurographic films, a clear-cut, medial, vertical and narrow picture which partitioned the PLES. However, this was not constant. Savolaine et al. also recognized this partition on epidurographic CT scans. During laminectomies, Luyendijk has taken photographs of a medial fold of the dura mater which appeared to hold it to the posterior vertebral arch, being collapsed on either side of the midline. He named it "plica mediana dorsalis durae matris" (PMD). Several anaesthetists considered that this could explain why epidural analgesia sometimes acted on one side only. Husemeyer and White, and Harrison et al., have tried to confirm this experimentally by making casts with polymerizing resins in cadavers. They did not get very convincing results. Blomberg also tried to see this space by epiduroscopy in the cadaver. Unfortunately, for technical reasons, his photographs were of poor quality. He, however, reported having seen each time the PMD and a band of connective tissue fixing it to the vertebral arch in the midline. However, all these anatomical studies used methods which alter the natural structures. Their results are therefore questionable. The PLES is a virtual space. Histological studies have shown that it is filled with fatty tissue between the dura and the vertebral arch. It is therefore conceivable that any liquid injected into the PLES, such as contrast medium or local anaesthetic, must push back the dura, the only tissue which can move to give it any room. The fatty tissue could therefore be compressed and take any of the shapes which have been described on epidurography. On the other hand, should it be torn, it seems this fatty tissue could make up these haphazard fibrous tracts tensed between the dura and the vertebral arch, such as described in classical anatomy, as Bonica recalled. These can be clearly seen during surgical and anatomical dissections, and during endoscopies carried out on cadavers with sufficient optical means, as opposed to the medial fibrous band fixing the dura to the vertebral arch.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1443817

  14. MARKOV CHAIN MONTE CARLO POSTERIOR SAMPLING WITH THE HAMILTONIAN METHOD

    SciTech Connect

    K. HANSON

    2001-02-01

    The Markov Chain Monte Carlo technique provides a means for drawing random samples from a target probability density function (pdf). MCMC allows one to assess the uncertainties in a Bayesian analysis described by a numerically calculated posterior distribution. This paper describes the Hamiltonian MCMC technique in which a momentum variable is introduced for each parameter of the target pdf. In analogy to a physical system, a Hamiltonian H is defined as a kinetic energy involving the momenta plus a potential energy {var_phi}, where {var_phi} is minus the logarithm of the target pdf. Hamiltonian dynamics allows one to move along trajectories of constant H, taking large jumps in the parameter space with relatively few evaluations of {var_phi} and its gradient. The Hamiltonian algorithm alternates between picking a new momentum vector and following such trajectories. The efficiency of the Hamiltonian method for multidimensional isotropic Gaussian pdfs is shown to remain constant at around 7% for up to several hundred dimensions. The Hamiltonian method handles correlations among the variables much better than the standard Metropolis algorithm. A new test, based on the gradient of {var_phi}, is proposed to measure the convergence of the MCMC sequence.

  15. Iodine-125 radiation of posterior uveal melanoma

    SciTech Connect

    Packer, S.

    1987-12-01

    Twenty-eight cases of posterior choroidal melanoma were treated with iodine-125 in gold eye plaques. Eleven cases were located within 3.0 mm of the optic nerve (group A), nine were within 3.0 mm of the fovea (group B), and eight were within 3.0 mm of the optic nerve and fovea (group C). The mean follow-up of group A was 46.3 months; group B, 25.5 months; and group C, 42.7 months. Complications included macular edema, cataract and tumor growth. Visual acuity remained within two lines of that tested preoperatively for 4 of 11 patients in group A, 4 of 9 in group B, and 5 of 8 in group C. These results with iodine-125 suggest it as an appropriate treatment for patients with choroidal melanoma located near optic nerve and/or macula.

  16. Cysticercosis in the posterior cranial fossa.

    PubMed

    Cheepsattayakorn, R; Tantachamroon, T

    1994-10-01

    Two cases of neurocysticercosis from Maharaj Nakorn Chiang Mai Hospital were reported with autopsy and surgical findings. The autopsy case was a 14-year-old girl who had a single cyst at the cisterna ambiens of the pineal region, causing hydrocephalus and severe brain edema accompanied with increased intracranial pressure and psychiatric problems but no definite localizing signs. The surgical case was a 35-year-old man with symptoms of increased intracranial pressure, localizing signs of ataxia of the left lower extremity and hearing loss in the right ear. Computed brain tomography showed a posterior fossa cyst with obstructive hydrocephalus. The cyst and the tissues from CP angle region were removed and sent to the Department of Pathology. Histopathologic appearance of both cases showed cysticercosis. PMID:7745377

  17. Diagnostics for insufficiencies of posterior calculations in Bayesian signal inference.

    PubMed

    Dorn, Sebastian; Oppermann, Niels; Ensslin, Torsten A

    2013-11-01

    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. PMID:24329375

  18. An ancestral regulatory network for posterior development in arthropods.

    PubMed

    McGregor, Alistair P; Pechmann, Matthias; Schwager, Evelyn E; Damen, Wim Gm

    2009-01-01

    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

  19. An ancestral regulatory network for posterior development in arthropods

    PubMed Central

    Pechmann, Matthias; Schwager, Evelyn E; Damen, Wim GM

    2009-01-01

    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

  20. Deep Posterior Compartment Strength and Foot Kinematics in Subjects With Stage II Posterior Tibial Tendon Dysfunction

    PubMed Central

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

    2010-01-01

    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. PMID:20371019

  1. Poster error probability in the Mu-11 Sequential Ranging System

    NASA Technical Reports Server (NTRS)

    Coyle, C. W.

    1981-01-01

    An expression is derived for the posterior error probability in the Mu-2 Sequential Ranging System. An algorithm is developed which closely bounds the exact answer and can be implemented in the machine software. A computer simulation is provided to illustrate the improved level of confidence in a ranging acquisition using this figure of merit as compared to that using only the prior probabilities. In a simulation of 20,000 acquisitions with an experimentally determined threshold setting, the algorithm detected 90% of the actual errors and made false indication of errors on 0.2% of the acquisitions.

  2. Guide star probabilities

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  3. Approximate analysis for failure probability of structural systems

    NASA Astrophysics Data System (ADS)

    Cai, Yin-Lin; Zhou, Jian-Sheng

    1992-03-01

    An approximate formula for calculating failure probability of structural systems is presented, which uses the lower and upper bounds of the first simple bounds to estimate the failure probability. In this formula, the correlation between each of the two failure modes of a structure is considered, but only the first failure probability of the failure modes is contained. Computations using the approximate formula are quite simple and accurate, with maximum error being within 5 percent.

  4. Launch Collision Probability

    NASA Technical Reports Server (NTRS)

    Bollenbacher, Gary; Guptill, James D.

    1999-01-01

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

  5. POSTERIOR CONSISTENCY IN NONPARAMETRIC REGRESSION PROBLEMS UNDER GAUSSIAN PROCESS PRIORS

    E-print Network

    POSTERIOR CONSISTENCY IN NONPARAMETRIC REGRESSION PROBLEMS UNDER GAUSSIAN PROCESS PRIORS By Taeryon regression is to put a nonparametric prior distribution on the unknown regression function using Gaussian processes. In this paper, we study posterior consistency in nonparametric regression problems using Gaussian

  6. Facilitating text reading in posterior cortical atrophy

    PubMed Central

    Rajdev, Kishan; Shakespeare, Timothy J.; Leff, Alexander P.; Crutch, Sebastian J.

    2015-01-01

    Objective: We report (1) the quantitative investigation of text reading in posterior cortical atrophy (PCA), and (2) the effects of 2 novel software-based reading aids that result in dramatic improvements in the reading ability of patients with PCA. Methods: Reading performance, eye movements, and fixations were assessed in patients with PCA and typical Alzheimer disease and in healthy controls (experiment 1). Two reading aids (single- and double-word) were evaluated based on the notion that reducing the spatial and oculomotor demands of text reading might support reading in PCA (experiment 2). Results: Mean reading accuracy in patients with PCA was significantly worse (57%) compared with both patients with typical Alzheimer disease (98%) and healthy controls (99%); spatial aspects of passages were the primary determinants of text reading ability in PCA. Both aids led to considerable gains in reading accuracy (PCA mean reading accuracy: single-word reading aid = 96%; individual patient improvement range: 6%–270%) and self-rated measures of reading. Data suggest a greater efficiency of fixations and eye movements under the single-word reading aid in patients with PCA. Conclusions: These findings demonstrate how neurologic characterization of a neurodegenerative syndrome (PCA) and detailed cognitive analysis of an important everyday skill (reading) can combine to yield aids capable of supporting important everyday functional abilities. Classification of evidence: This study provides Class III evidence that for patients with PCA, 2 software-based reading aids (single-word and double-word) improve reading accuracy. PMID:26138948

  7. "Apperceptive" alexia in posterior cortical atrophy.

    PubMed

    Mendez, Mario F; Shapira, Jill S; Clark, David G

    2007-02-01

    The most common presenting complaint in posterior cortical atrophy (PCA) is reading difficulty. Although often described as an alexia without agraphia, alexia in PCA may have multiple causes, including a primary visuoperceptual etiology, attentional alexia, and central reading difficulty. This study evaluated 14 patients with early PCA and disturbances in reading ability in comparison to 14 normal controls. All 14 patients had a progressive disorder of complex visual functions and neuroimaging evidence of occipitoparietal dysfunction. They underwent a task requiring identification of single letters with and without flanking distractors. They also read single words consisting of regular English spelling or irregular grapheme-phoneme correspondence (irregular words) and pronounceable nonsense words (pseudowords). The PCA patients made errors in letter identification when letters were flanked by visually similar letters or numbers. They could read most single regular and irregular words but made visual errors and had particular trouble with pseudowords. They could not use a letter-by-letter reading strategy effectively. The PCA patients had similar difficulties on other visuoperceptual tests. These findings are consistent with an alexia manifested by perceptual and attentional difficulty on attempting serial visual processing of letters in the context of other letters. This "apperceptive alexia" results when the configuration of letters into words is impaired during letter-by-letter reading. Disproportionate difficulty reading pseudowords suggests an additional impairment in phonological processing. PCA patients have variable neuropathology and individual patients may have other contributions to their reading impairment. PMID:17405672

  8. Automatic quantification of posterior capsule opacification

    NASA Astrophysics Data System (ADS)

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

    2000-06-01

    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.

  9. Abnormal visual phenomena in posterior cortical atrophy.

    PubMed

    Crutch, Sebastian J; Lehmann, Manja; Gorgoraptis, Nikos; Kaski, Diego; Ryan, Natalie; Husain, Masud; Warrington, Elizabeth K

    2011-01-01

    Individuals with posterior cortical atrophy (PCA) report a host of unusual and poorly explained visual disturbances. This preliminary report describes a single patient (CRO), and documents and investigates abnormally prolonged colour afterimages (concurrent and prolonged perception of colours complimentary to the colour of an observed stimulus), perceived motion of static stimuli, and better reading of small than large letters. We also evaluate CRO's visual and vestibular functions in an effort to understand the origin of her experience of room tilt illusion, a disturbing phenomenon not previously observed in individuals with cortical degenerative disease. These visual symptoms are set in the context of a 4-year longitudinal neuropsychological and neuroimaging investigation of CRO's visual and other cognitive skills. We hypothesise that prolonged colour after-images are attributable to relative sparing of V1 inhibitory interneurons; perceived motion of static stimuli reflects weak magnocellular function; better reading of small than large letters indicates a reduced effective field of vision; and room tilt illusion effects are caused by disordered integration of visual and vestibular information. This study contributes to the growing characterisation of PCA whose atypical early visual symptoms are often heterogeneous and frequently under-recognised. PMID:20818540

  10. [Anterior chamber versus posterior chamber phakic IOLs].

    PubMed

    Cochener, B

    2007-05-01

    At a time when some of the limitations of photoablation have been defined, such as worry concerning secondary ectasia, a renewed interest in phakic implantation has arisen. This is driven by the goal of avoiding correcting high ametropia with LASIK and is based on the development of soft foldable biomaterials. When all phakic IOLs are in front of the natural lens, two varieties of lenses can be distinguished, depending on whether it is located in the anterior or posterior chamber. The various models available in 2006 and those under current evaluation are reviewed. We do not report details of clinical studies that vary in cohort size and follow-up. The advantages and limitations are discussed for each type of phakic IOL. Adequate although not exclusive indications are deduced. There is no phakic lens that has proved to be superior to the others in terms of safety. All have the ability to provide a visual benefit with a gain in best corrected visual acuity. The difference is based on anatomical effects, requiring long-term follow-up in the evaluation of angles, lens, iris, and endothelium. PMID:17568350

  11. Posterior Reversible Leukoencephalopathy Syndrome Associated with Pazopanib

    PubMed Central

    Foerster, Robert; Welzel, Thomas; Debus, Juergen; Gruellich, Carsten; Jaeger, Dirk; Potthoff, Karin

    2013-01-01

    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

  12. Glioependymal cyst in the posterior fossa.

    PubMed

    Tsuchida, T; Kawamoto, K; Sakai, N; Tsutsumi, A

    1997-01-01

    A large cyst filled with clear fluid was resected from the cerebellum of a 29-year-old man. By light microscopy the cyst was lined by flat epithelial cells. These epithelial cells abutted on a glial layer and immunohistochemical staining revealed that some of them expressed glial fibrillary acidic protein. Corpora amylacea were noted within the glial layer. Ultrastructurally, 2 types of cells lining the cyst were identified. One was characterized by electron-dense cytoplasm, cytoplasmic vacuoles, microvilli without surface-coated material, cilia, and basal bodies. The other was a cell with a smooth cytoplasmic membrane, round nucleus, and clear cytoplasm. Zonulae adherentes was observed between cyst lining cells and the cyst lining cells were shown to rest directly on the glial layer. Surprisingly, myelinated axons were identified in the glial layer, although nerve cells were not identified. These findings are compatible with those of a glioependymal cyst. The origin of glioependymal cysts of the posterior fossa is not understood, but possibilities include neuroglial heterotopia, persistent Blake's pouch (diverticulum of the roof of fourth ventricle), and remnants of a tela chorioidea. The location of the cyst and the presence of myelinated axons in the cyst wall may be best explained by an origin from neuroglial heterotopia. PMID:9020388

  13. Isolated posterior capsular rupture following blunt head trauma

    PubMed Central

    Mansour, Ahmad M; Jaroudi, Mahmoud O; Hamam, Rola N; Maalouf, Fadi C

    2014-01-01

    Closed-globe traumatic cataract is not uncommon in males in the pediatric age group. However, there is a relative paucity of literature on isolated posterior lens capsule rupture associated with closed-globe traumatic cataract. We report a case of a 6-year-old boy who presented with white cataract 1 day after blunt trauma to the forehead associated with posterior capsular rupture that was detected by B-scan ultrasonography preoperatively. No stigmata of trauma outside the posterior capsule could be detected by slit-lamp exam, funduscopy, and optical coherence tomography. Phacoemulsification with posterior chamber intraocular lens implant was performed 24 hours after trauma, with the patient achieving 6/6 visual acuity 1 week and 6 months after surgery. Our case is unique, being the youngest (amblyogenic age) to be reported, with prompt surgical intervention, and with no signs of trauma outside the posterior capsule. PMID:25506201

  14. Posterior Corneal Surface Stability after Femtosecond Laser-Assisted Keratomileusis

    PubMed Central

    Cagini, Carlo; Messina, Marco; Lupidi, Marco; Piccinelli, Francesco; Fiore, Tito; Fruttini, Daniela; Spadea, Leopoldo

    2015-01-01

    The purpose of this study was to evaluate posterior corneal surface variation after femtosecond laser-assisted keratomileusis in patients with myopia and myopic astigmatism. Patients were evaluated by corneal tomography preoperatively and at 1, 6, and 12 months. We analyzed changes in the posterior corneal curvature, posterior corneal elevation, and anterior chamber depth. Moreover, we explored correlation between corneal ablation depth, residual corneal thickness, percentage of ablated corneal tissue, and preoperative corneal thickness. During follow-up, the posterior corneal surface did not have a significant forward corneal shift: no significant linear relationships emerged between the anterior displacement of the posterior corneal surface and corneal ablation depth, residual corneal thickness, or percentage of ablated corneal tissue. PMID:26483972

  15. The Probability Calculus 1 0 . THE PROBABILITY OPERATOR

    E-print Network

    Fitelson, Branden

    number of possible outcomes #12;CHAP. 101 THE PROBABILITY CALCULUS SOLVED PROBLEM 1 0 . Consider a situa probabilities, they shed a great deal of light on the nature of probability and enable us to solve someChapter 10 The Probability Calculus 1 0 . THE PROBABILITY OPERATOR Chapter 3 illustrates how truth

  16. Digging up the recent Spanish memory: genetic identification of human remains from mass graves of the Spanish Civil War and posterior dictatorship.

    PubMed

    Baeta, Miriam; Núñez, Carolina; Cardoso, Sergio; Palencia-Madrid, Leire; Herrasti, Lourdes; Etxeberria, Francisco; de Pancorbo, Marian M

    2015-11-01

    The Spanish Civil War (1936-1939) and posterior dictatorship (until 1970s) stands as one of the major conflicts in the recent history of Spain. It led to nearly two hundred thousand men and women executed or murdered extra-judicially or after dubious legal procedures. Nowadays, most of them remain unidentified or even buried in irretraceable mass graves across Spain. Here, we present the genetic identification of human remains found in 26 mass graves located in Northern Spain. A total of 252 post-mortem remains were analyzed and compared to 186 relatives, allowing the identification of 87 victims. Overall, a significant success of DNA profiling was reached, since informative profiles (? 12 STRs and/or mitochondrial DNA profile) were obtained in 85.71% of the remains. This high performance in DNA profiling from challenging samples demonstrated the efficacy of DNA extraction and amplification methods used herein, given that only around 14.29% of the samples did not provide an informative genetic profile for the analysis performed, probably due to the presence of degraded and/or limited DNA in these remains. However, this study shows a partial identification success rate, which is clearly a consequence of the lack of both appropriate family members for genetic comparisons and accurate information about the victims' location. Hence, further perseverance in the exhumation of other intact graves as well as in the search of more alleged relatives is crucial in order to facilitate and increase the number of genetic identifications. PMID:26378723

  17. Activation of the retrotrapezoid nucleus by posterior hypothalamic stimulation.

    PubMed

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

    2009-11-01

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

  18. Vitamin D deficiency and posterior subcapsular cataract

    PubMed Central

    Brown, Craig J; Akaichi, Faical

    2015-01-01

    Purpose To evaluate risk factors associated with posterior subcapsular cataract (PSC) development and the relationship between vitamin D deficiency and etiology of PSC. Methods Of 195 consecutive patients from a private ophthalmology practice, diagnosed with PSC, serum vitamin D3 (25-OH D) levels were obtained for 175, and associations among risk factors, comorbidities, and PSC were assessed. Results In all 175 PSC patients, mean 25-OH D levels were low (24 ng/mL ±11 SD) compared with age/sex-matched standards. Significant differences in 25-OH D levels were noted between PSC subjects taking/not taking calcium supplements, systemic steroids, osteoporosis medications, etc. Alone, smoking status and calcium channel blockers and/or topical steroids use made no significant difference in PSC subjects 25-OH D levels, but two or more of these factors were associated with lowered levels of 25-OH D (P<0.001). Low vitamin D was correlated with female sex, autoimmune disease, and non-skin cancer diagnosis, but not with age, or other comorbidities or medication use. In five early-stage PSC patients taking 5,000 IU of 25-OH D daily for vitamin D deficiency, there was resolution of their cataracts during the 2-year follow-up period. Conclusion Vitamin D levels for most PSC patients fell below the 30 ng/mL calcium homeostasis threshold. Some comorbidities and non-ophthalmic interventions are associated with the development of PSC at less depressed levels of 25-OH D. In this series, vitamin D deficiency was associated with PSC cataract, suggesting that raising the level of vitamin D intake may reduce PSC incidence. PMID:26124632

  19. The language profile of Posterior Cortical Atrophy

    PubMed Central

    Crutch, Sebastian J.; Lehmann, Manja; Warren, Jason D.; Rohrer, Jonathan D.

    2015-01-01

    Background Posterior Cortical Atrophy (PCA) is typically considered to be a visual syndrome, primarily characterised by progressive impairment of visuoperceptual and visuospatial skills. However patients commonly describe early difficulties with word retrieval. This paper details the first systematic analysis of linguistic function in PCA. Characterising and quantifying the aphasia associated with PCA is important for clarifying diagnostic and selection criteria for clinical and research studies. Methods Fifteen patients with PCA, 7 patients with logopenic/phonological aphasia (LPA) and 18 age-matched healthy participants completed a detailed battery of linguistic tests evaluating auditory input processing, repetition and working memory, lexical and grammatical comprehension, single word retrieval and fluency, and spontaneous speech. Results Relative to healthy controls, PCA patients exhibited language impairments across all the domains examined, but with anomia, reduced phonemic fluency and slowed speech rate the most prominent deficits. PCA performance most closely resembled that of LPA patients on tests of auditory input processing, repetition and digit span, but was relatively stronger on tasks of comprehension and spontaneous speech. Conclusions The study demonstrates that in addition to the well-reported degradation of vision, literacy and numeracy, PCA is characterised by a progressive oral language dysfunction with prominent word retrieval difficulties. Overlap in the linguistic profiles of PCA and LPA, which are both most commonly caused by Alzheimer’s disease, further emphasises the notion of a phenotypic continuum between typical and atypical manifestations of the disease. Clarifying the boundaries between AD phenotypes has important implications for diagnosis, clinical trial recruitment and investigations into biological factors driving phenotypic heterogeneity in AD. Rehabilitation strategies to ameliorate the phonological deficit in PCA are required. PMID:23138762

  20. Machine Learning ! ! ! ! !Srihari Probability Theory

    E-print Network

    and manipulation of uncertainty 2 apples 3 oranges 3 apples 1 orange Box is random variable B (has values r or b ! ! ! ! !Srihari 3 Probabilities of Interest · Marginal Probability ­what is the probability of an apple? · Joint Probability ­What is the probability of orange AND blue box? 2 apples 3 oranges 3 apples 1 orange

  1. Management of Posterior Malleolar Fractures: A Systematic Review.

    PubMed

    Odak, Saurabh; Ahluwalia, Raju; Unnikrishnan, Puthanveettil; Hennessy, Michael; Platt, Simon

    2016-01-01

    Posterior malleolar fractures are relatively common and usually result from rotational ankle injuries. Although treatment of associated lateral and medial structures is well established, several controversies exist in the management of posterior malleolus fractures. We performed a systematic review of the current published data with regard to the diagnosis, management, and prognosis of posterior malleolus fractures. A total of 33 studies (8 biomechanical and 25 clinical) with >950 patients were reviewed. The outcome of ankle fractures with posterior malleolar involvement was poor; however, the evidence was not enough to prove that the size of the posterior malleolus affects the outcome. Significant heterogeneity was noted in the cutoff size of the posterior malleolar fragment in determining management. The outcome was related to other factors, such as fracture displacement, congruency of the articular surface, and residual tibiotalar subluxation. Indirect evidence showed that large fracture fragments were associated with fracture dislocations and ankle instability and, thus, might require surgical fixation. We have concluded that the evidence to prove that the size of the posterior malleolar affects the outcome of ankle fractures is not enough, and the decision to treat these fractures should be determined by other factors, as stated previously. PMID:26100091

  2. Probability and Cancer Clusters

    ERIC Educational Resources Information Center

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

    2009-01-01

    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

  3. Logic, Truth and Probability

    E-print Network

    Gunn Quznetsov

    1998-08-31

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

  4. Probability paradoxes Helmer Aslaksen

    E-print Network

    Aslaksen, Helmer

    .999r + 0.005(1 - r) = 999r 5 + 994r If r = 0.001, then P(I|T) = 0.167. 8 #12;Benford's Law Benford's Law states that in "naturally oc- curing" sets of numbers, the probability that the first digit is d

  5. Univariate Probability Distributions

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  6. Logic and probability

    E-print Network

    G. A. Quznetsov

    2010-09-14

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

  7. Detection of Neisseria gonorrhoeae Isolates from Tonsils and Posterior Oropharynx.

    PubMed

    Bissessor, M; Whiley, D M; Lee, D M; Snow, A F; Fairley, C K; Peel, J; Bradshaw, C S; Hocking, J S; Lahra, M M; Chen, M Y

    2015-11-01

    We examined the factors influencing gonorrhea detection at the pharynx. One hundred men infected with Neisseria gonorrhoeae were swabbed from the tonsils and posterior oropharynx. N. gonorrhoeae was reisolated from the tonsils and posterior oropharynx in 62% and 52%, respectively (P = 0.041). Culture positivity was greater with higher gonococcal DNA loads at the tonsils (P = 0.001) and oropharynx (P < 0.001). N. gonorrhoeae can be cultured from the tonsils and posterior oropharynx with greater isolation rates where gonococcal loads are higher. PMID:26292303

  8. Incidence and surgical importance of the posterior gastric artery.

    PubMed Central

    Suzuki, K; Prates, J C; DiDio, L J

    1978-01-01

    In a series of 61 adult cadavers, the posterior gastric artery was found in 38 (62.3%), originating from the superior aspect of the mid-third of the splenic artery. The posterior gastric artery, running behind the parietal peritoneum of the omental bursa, produced a peritoneal fold before reaching the posterior wall of the superior portion of the gastric body, near the cardiac region, and the fundus. Its high incidence, hidden origin, deep course, and distribution make this artery very important for surgical procedures relating to the stomach, pancreas, spleen, and celiac region. It may be crucial, especially if partial gastric resection of splenectomy have obliterated other gastric vessels. PMID:629615

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

    NASA Technical Reports Server (NTRS)

    Chiu, J. Christine; Petty, Grant W.

    2005-01-01

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

  10. Hf Transition Probabilities and Abundances

    E-print Network

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

    2006-11-01

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

  11. Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics

    PubMed Central

    Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

    2014-01-01

    Objectives: The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. Methods: A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. Results: 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p?posterior mandible occurred with significant frequency (p?=?0.001) when the posterior maxillary fractures involved only the sinus. Conclusions: Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture. PMID:24336313

  12. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  13. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  14. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  15. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  16. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  17. Waste Package Misload Probability

    SciTech Connect

    J.K. Knudsen

    2001-11-20

    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.

  18. Arthroscopic preparation of the posterior and posteroinferior glenoid labrum.

    PubMed

    Provencher, Matthew T; Romeo, Anthony A; Solomon, Daniel J; Bach, Bernard R; Cole, Brian J

    2007-11-01

    Using an anterior portal for a labral elevator and shaver instrument, with the arthroscope in the anterosuperior portal, allows the posterior and posteroinferior chondrolabral junction to be safely prepared. PMID:18019981

  19. Vitrectorhexis versus forceps posterior capsulorhexis in pediatric cataract surgery

    PubMed Central

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

    2013-01-01

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

  20. Vitrectorhexis versus forceps posterior capsulorhexis in pediatric cataract surgery.

    PubMed

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

    2013-07-01

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

  1. Approximation of Failure Probability Using Conditional Sampling

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  2. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    PubMed

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions whose frequency correlated significantly with generalized reductions in cortical thickness. Patients with both posterior cortical atrophy and typical Alzheimer's disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in posterior cortical atrophy, and highlights multiple aspects of saccadic performance which distinguish posterior cortical atrophy from typical Alzheimer's disease. We suggest the posterior cortical atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in posterior cortical atrophy and many other patients with dementia-related visual impairment. PMID:25895507

  3. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

    PubMed Central

    Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

    2015-01-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal ‘visual dementia’ and most common atypical Alzheimer’s disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients’ (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer’s disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer’s disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer’s disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with ‘sticky fixation’. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer’s disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions whose frequency correlated significantly with generalized reductions in cortical thickness. Patients with both posterior cortical atrophy and typical Alzheimer’s disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in posterior cortical atrophy, and highlights multiple aspects of saccadic performance which distinguish posterior cortical atrophy from typical Alzheimer’s disease. We suggest the posterior cortical atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in posterior cortical atrophy and many other patients with dementia-related visual impairment. PMID:25895507

  4. Comparative Study of Modified Posterior Operation to Treat Kümmell's Disease

    PubMed Central

    Wang, Feng; Wang, Dachuan; Tan, Bingyi; Dong, Jun; Feng, Rongjie; Yuan, Zenong; Wang, Naiguo

    2015-01-01

    Abstract The present study aimed at examining the curative effect of modified posterior operation on treatment of Kümmell's disease. About 30 patients of Kümmell's disease with complete image and clinical data treated during June 2004 to July 2013 were conducted with anterior and posterior approaches, respectively. Kyphotic Cobb angle, fractured vertebra wedge angle, and the anterior and posterior heights of fractured vertebra were all measured through x-ray before and after operation, and the pain visual analog scale (VAS) was determined for evaluating the effect of operations. The injury and restoration of neurological function were assessed using Frankel classification. Patients in group A were treated with anterior operation, whereas group B was posterior operation. Postoperatively, VAS score, kyphotic Cobb angle, anterior vertebra height, and pathologic vertebra wedge angle were all significantly improved in patients with Kümmell's disease receiving modified posterior operation (group B). Similar results were also observed in patients with anterior operation. The improvement of VAS and correction rate of kyphotic Cobb angle indicated equivalent effects of posterior and anterior operations. Meanwhile, alleviated neurological function damage was observed in 2 groups. Relevant factor analysis illustrated that there was no significant correlation of the severity and improvement rate of pain symptoms with age, medical history, anterior and posterior vertebra heights, kyphotic Cobb angle, and pathological vertebra wedge angle. Compared with traditional anterior approach, modified posterior operation, adopting transpedicular vertebral body grafting combined with vertebral pedicle screw fixation, could produce equivalent effects on kyphosis correction, pain relief, and improvement of neurological function in patients with Kümmell's disease. PMID:26426639

  5. Posterior interosseous nerve palsy in a machine gunner.

    PubMed

    Sonna, L A; Scott, B R

    1995-07-01

    We report the case of a 19-year-old Infantryman who developed posterior interosseous nerve palsy and a transient sensory deficit in a radial distribution after prolonged carrying of an M60 machine gun. Posterior interosseous nerve palsy has been reported in association with a variety of activities involving forceful, repetitive pronation and supination; however, to our knowledge, no previous cases of this palsy have been reported in association with use of a military weapon. PMID:7659246

  6. Comparative Study of Modified Posterior Operation to Treat Kümmell's Disease.

    PubMed

    Wang, Feng; Wang, Dachuan; Tan, Bingyi; Dong, Jun; Feng, Rongjie; Yuan, Zenong; Wang, Naiguo

    2015-09-01

    The present study aimed at examining the curative effect of modified posterior operation on treatment of Kümmell's disease. About 30 patients of Kümmell's disease with complete image and clinical data treated during June 2004 to July 2013 were conducted with anterior and posterior approaches, respectively. Kyphotic Cobb angle, fractured vertebra wedge angle, and the anterior and posterior heights of fractured vertebra were all measured through x-ray before and after operation, and the pain visual analog scale (VAS) was determined for evaluating the effect of operations. The injury and restoration of neurological function were assessed using Frankel classification. Patients in group A were treated with anterior operation, whereas group B was posterior operation. Postoperatively, VAS score, kyphotic Cobb angle, anterior vertebra height, and pathologic vertebra wedge angle were all significantly improved in patients with Kümmell's disease receiving modified posterior operation (group B). Similar results were also observed in patients with anterior operation. The improvement of VAS and correction rate of kyphotic Cobb angle indicated equivalent effects of posterior and anterior operations. Meanwhile, alleviated neurological function damage was observed in 2 groups. Relevant factor analysis illustrated that there was no significant correlation of the severity and improvement rate of pain symptoms with age, medical history, anterior and posterior vertebra heights, kyphotic Cobb angle, and pathological vertebra wedge angle. Compared with traditional anterior approach, modified posterior operation, adopting transpedicular vertebral body grafting combined with vertebral pedicle screw fixation, could produce equivalent effects on kyphosis correction, pain relief, and improvement of neurological function in patients with Kümmell's disease. PMID:26426639

  7. Erupted complex odontoma of the posterior maxilla: A rarity

    PubMed Central

    Verma, Sonika; Arul, A. Sri Kennath J.; Arul, A. Sri Sennath J.; Chitra, S.

    2015-01-01

    Complex odontomas, hamartomas of aborted tooth development, mainly occur in posterior part of the mandible and rarely erupt into the oral cavity. The spontaneous eruption may be associated with pain, inflammation of adjacent soft tissues or recurrent infection. The present case of complex odontoma is of particular interest due to its apparent eruption in the maxillary posterior segment, its association with agenesis of the second molar and impacted third molar; with the lesion being completely asymptomatic. PMID:26604611

  8. Posterior partially edentulous jaws, planning a rehabilitation with dental implants

    PubMed Central

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

    2015-01-01

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

  9. Defining Predictive Probability Functions for Species Sampling Models

    PubMed Central

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

    2013-01-01

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

  10. Computational modelling of mobile bearing TKA anterior-posterior dislocation.

    PubMed

    Müller, J H; Zakaria, T; van der Merwe, W; D'Angelo, F

    2016-04-01

    Anterior-posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert's articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445 N vs. 412 N). The unconstrained insert dislocated by means of spin-out whereas in the constrained TKA the femur dislocated from the bearing during posterior drawer and the bearing from the baseplate during anterior drawer. MCL function is an important consideration during ligament balancing since a ± 10% variation in MCL tension affects dislocation forces by ± 20%. The simulation platform provided the means to investigate TKA designs in terms of anterior-posterior stability as a function of knee flexion, collateral ligament function and mechanical morphology. PMID:26047039

  11. Strategy Guideline: Accurate Heating and

    E-print Network

    (HVAC) Mechanical Contractors · HVAC System Designers · Builders · House Remodelers. This guide can, as the first step of HVAC system design. Accurate load calculations have a direct impact on energy efficiency of the iterative HVAC design procedure, as a full HVAC design involves much more than just the load calculation

  12. SYSTEMS BIOLOGY Accurate information transmission

    E-print Network

    Tsimring, Lev S.

    SYSTEMS BIOLOGY Accurate information transmission through dynamic biochemical signaling networks) and variability in cellular states (extrinsic noise) degrade information transmitted through signaling networks-induced information loss. In the extracellular signal­regulated kinase (ERK), calcium (Ca2+ ), and nuclear factor

  13. Probability (Math/Stat 511)

    E-print Network

    Sharpley, Robert

    probability distribution. Describe the typical random variable X which has this as its probability mass. Suppose the probability that a basketball player makes a free throw is 70% and that each attempt with probability mass function f(x) = 4 - |5 - x| 16 , x = 2, 3, 4, 5, 6, 7, 8. a.) Compute the mean and variance

  14. One step arthroscopically assisted Latarjet and posterior bone-block, for recurrent posterior instability and anterior traumatic dislocation

    PubMed Central

    D’Ambrosi, Riccardo; Perfetti, Carlo; Garavaglia, Guido; Taverna, Ettore

    2015-01-01

    This case presents the challenges of the surgical management for a patient with a history of recurrent posterior shoulder instability and subsequently traumatic anterior dislocation. The patient was already on the waiting list for an arthroscopic posterior stabilization with anchors, when a car accident caused an additional anterior shoulder dislocation. This traumatic anterior dislocation created a bone loss with a glenoid fracture and aggravated the preexisting posterior instability. In order to address both problems, we decided to perform an arthroscopically assisted Latarjet procedure for anterior instability and to stabilize with a bone graft for posterior instability. To our best knowledge, this type of surgical procedure has so far never been reported in the literature. The purpose of this report is to present the surgical technique and to outline the decision making process. PMID:26288539

  15. The utility of Bayesian predictive probabilities for interim monitoring of clinical trials

    PubMed Central

    Connor, Jason T.; Ayers, Gregory D; Alvarez, JoAnn

    2014-01-01

    Background Bayesian predictive probabilities can be used for interim monitoring of clinical trials to estimate the probability of observing a statistically significant treatment effect if the trial were to continue to its predefined maximum sample size. Purpose We explore settings in which Bayesian predictive probabilities are advantageous for interim monitoring compared to Bayesian posterior probabilities, p-values, conditional power, or group sequential methods. Results For interim analyses that address prediction hypotheses, such as futility monitoring and efficacy monitoring with lagged outcomes, only predictive probabilities properly account for the amount of data remaining to be observed in a clinical trial and have the flexibility to incorporate additional information via auxiliary variables. Limitations Computational burdens limit the feasibility of predictive probabilities in many clinical trial settings. The specification of prior distributions brings additional challenges for regulatory approval. Conclusions The use of Bayesian predictive probabilities enables the choice of logical interim stopping rules that closely align with the clinical decision making process. PMID:24872363

  16. Achieving target voriconazole concentrations more accurately in children and adolescents.

    PubMed

    Neely, Michael; Margol, Ashley; Fu, Xiaowei; van Guilder, Michael; Bayard, David; Schumitzky, Alan; Orbach, Regina; Liu, Siyu; Louie, Stan; Hope, William

    2015-06-01

    Despite the documented benefit of voriconazole therapeutic drug monitoring, nonlinear pharmacokinetics make the timing of steady-state trough sampling and appropriate dose adjustments unpredictable by conventional methods. We developed a nonparametric population model with data from 141 previously richly sampled children and adults. We then used it in our multiple-model Bayesian adaptive control algorithm to predict measured concentrations and doses in a separate cohort of 33 pediatric patients aged 8 months to 17 years who were receiving voriconazole and enrolled in a pharmacokinetic study. Using all available samples to estimate the individual Bayesian posterior parameter values, the median percent prediction bias relative to a measured target trough concentration in the patients was 1.1% (interquartile range, -17.1 to 10%). Compared to the actual dose that resulted in the target concentration, the percent bias of the predicted dose was -0.7% (interquartile range, -7 to 20%). Using only trough concentrations to generate the Bayesian posterior parameter values, the target bias was 6.4% (interquartile range, -1.4 to 14.7%; P = 0.16 versus the full posterior parameter value) and the dose bias was -6.7% (interquartile range, -18.7 to 2.4%; P = 0.15). Use of a sample collected at an optimal time of 4 h after a dose, in addition to the trough concentration, resulted in a nonsignificantly improved target bias of 3.8% (interquartile range, -13.1 to 18%; P = 0.32) and a dose bias of -3.5% (interquartile range, -18 to 14%; P = 0.33). With the nonparametric population model and trough concentrations, our control algorithm can accurately manage voriconazole therapy in children independently of steady-state conditions, and it is generalizable to any drug with a nonparametric pharmacokinetic model. (This study has been registered at ClinicalTrials.gov under registration no. NCT01976078.). PMID:25779580

  17. Probability Forecasting Using Monte Carlo Simulation

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  18. Fine structure of bat deep posterior lingual glands (von Ebner's)

    PubMed

    Azzali, G; Gatti, R; Bucci, G; Orlandini, G

    1989-10-01

    We studied the morphology and ultrastructure of the bat (Pipistrellus k.k. and Rhinolophus f.e.) deep posterior lingual glands (Ebner's glands) during hibernation, summer and after stimulation with pilocarpine. Ebner's glands are formed by serous tubulo-alveolar adenomeres and by an excretory system organized in intercalated ducts, long excretory ducts and a main excretory duct. The latter opens in the vallum which surrounds the circumvallate papillae and in the groove of the foliate papillae. The secretory cells, which lack basal folds, show abundant and dense granules (PAS+, Alcian blue -), microvilli (scarce during hibernation), a Golgi apparatus (well developed during summer and after stimulation with pilocarpine), a large nucleus and RER cisternae stacked at the basal pole. Centrioles, lipid droplets, heterogeneous bodies (in content and density, probably lipofuscin bodies), lysosomal multivesicular bodies and large, dense granules with a microcrystalline structure were also encountered. The lateral membranes of adjacent cells are joined by desmosomes; their interdigitations are neither numerous nor prominent during summer. Microfilaments, often gathered in small bundles, lie in the lateral, peripheral cytoplasm without any relation with desmosomes. In summer and particularly after stimulation with pilocarpine, the apical pole of the secretory cells is characterized by many long microvilli, pedunculated hyaloplasmic protrusions and secretory granules. During hibernation the lumen is filled with secretory material. Myoepithelial cells are arranged among secretory cells or between them and the basal lamina. The short intercalated ducts show similarities with the analogous ducts of the parotid gland. Striated ducts are absent. Excretory ducts are endowed with: a) an inner layer of cuboidal cells characterized by poorly developed cytoplasmic organelles, rare dense granules and a few small microvilli; b) an outer layer of basal cells lying on the basal lamina. Myoepithelial cells are absent. The main excretory duct is lined by a stratified epithelium with an inner layer of conical-pyramidal cells surrounded by two-three rows of basal cells. The conical-pyramidal cells show poorly developed organelles, an apical border with small short microvilli and a prominent terminal web. PMID:2804953

  19. Intro Probability Rabbits Description Predictions Ontology of Earthquake Probability: Metaphor

    E-print Network

    Stark, Philip B.

    Intro Probability Rabbits Description Predictions Ontology of Earthquake Probability: Metaphor" mean? Stochastic models for seismicity have a peculiar ontological status that makes it difficult "automatic alarm" strategy. I contend that probabilistic models for earthquakes lack adequate scientific

  20. Surgical approaches to posterior polar cataract: a review

    PubMed Central

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

    2012-01-01

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

  1. Surgical approaches to posterior polar cataract: a review.

    PubMed

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

    2012-06-01

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

  2. Posterior sagittal approach in complicated Swenson's pull-through

    PubMed Central

    Sowande, O. A.; Adejuyigbe, O.

    2008-01-01

    Context: Swenson's pull-through is one of the standard operations for the treatment of children with Hirschsprung's disease. Complications arising from the operation are difficult to treat because of fibrosis in the pelvis. The posterior sagittal approach may be a safer alternative. Aims: The aim of this paper is to highlight our experience with the use of the posterior sagittal trans-sphincteric approach to treat unusual complications of Swenson's pull-through. Settings and Design: A retrospective study of four patients who had posterior sagittal repair of their complications of Swenson pull-through at the Obafemi Awolowo University Teaching Hospital, Ile Ife, Nigeria. Materials and Methods: Four cases of Hirschsprung's disease that developed post-Swenson pull-through complications are presented. There were three males and one female. Their age ranged between 10 months and 15 years. The patients had rectovaginal fistula, rectourethral fistula, high trans-sphincteric fistula-in-ano and complete anastomotic disruption. Result: All the patients were successfully treated using the posterior sagittal approach. The approach was used twice in one patient without significant sequelae. The three patients were old enough to be assessed and had a Kelly score of 4-6 at follow-up. Conclusion: The posterior sagittal technique offers a safe approach to treat the complications of Swenson pull-through. PMID:20177480

  3. Flexor Digitorum Accessorius Longus: Importance of Posterior Ankle Endoscopy

    PubMed Central

    Batista, Jorge Pablo; del Vecchio, Jorge Javier; Golanó, Pau; Vega, Jordi

    2015-01-01

    Endoscopy for the posterior region of the ankle through two portals is becoming more widespread for the treatment of a large number of conditions which used to be treated with open surgery years ago. The tendon of the flexor hallucis longus (FHL) travels along an osteofibrous tunnel between the posterolateral and posteromedial tubercles of the talus. Chronic inflammation of this tendon may lead to painful stenosing tenosynovitis. The aim of this report is to describe two cases depicting an accessory tendon which is an anatomical variation of the flexor hallucis longus in patients with posterior friction syndrome due to posterior ankle impingement and associated with a posteromedial osteochondral lesion of the talus. The anatomical variation (FDAL) described was a finding during an endoscopy of the posterior region of the ankle, and we have spared it by sectioning the superior flexor retinaculum only. The accessory flexor digitorum longus is an anatomical variation and should be taken into account when performing an arthroscopy of the posterior region of the ankle. We recommend this treatment on this type of injury although we admit this does not make a definite conclusion. PMID:26060592

  4. Posterior myocardial infarction: the dark side of the moon.

    PubMed

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

    2007-01-01

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

  5. Fusion probability in heavy nuclei

    NASA Astrophysics Data System (ADS)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2015-03-01

    Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: has been shown to vary with entrance channel mass asymmetry, ? (or charge product, ZpZt ), as well as with fissility of the CN, ?CN. No parameter has been found to be adequate as a single scaling variable to determine . Approximate boundaries have been obtained from where starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross sections over a wider energy range for many more reactions is desired for accurate determination of and more insight into the dynamics of fusion in the heavy mass region.

  6. Fast and accurate database searches with MS-GF+Percolator

    SciTech Connect

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

    2014-02-28

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

  7. Emptiness Formation Probability

    E-print Network

    Nicholas Crawford; Stephen Ng; Shannon Starr

    2014-12-30

    We present rigorous upper and lower bounds on the emptiness formation probability for the ground state of a spin-$1/2$ Heisenberg XXZ quantum spin system. For a $d$-dimensional system we find a rate of decay of the order $\\exp(-c L^{d+1})$ where $L$ is the sidelength of the box in which we ask for the emptiness formation event to occur. In the $d=1$ case this confirms previous predictions made in the integrable systems community, though our bounds do not achieve the precision predicted by Bethe ansatz calculations. On the other hand, our bounds in the case $d \\geq 2$ are new. The main tools we use are reflection positivity and a rigorous path integral expansion which is a variation on those previously introduced by Toth, Aizenman-Nachtergaele and Ueltschi.

  8. Probabilities for Solar Siblings

    NASA Astrophysics Data System (ADS)

    Valtonen, Mauri; Myllari, A.; Bobylev, V. V.; Bajkova, A.

    2013-05-01

    Abstract (2,250 Maximum Characters): We have shown previously (Bobylev et al. 2011) that some of the stars in the Solar neighborhood today may have originated in the same star cluster as the Sun, and could thus be called Solar Siblings. In this work we investigate the sensitivity of this result to Galactic models and to parameters of these models, and also extend the sample of orbits. There are a number of good candidates for the Sibling category, but due to the long period of orbit evolution since the break-up of the birth cluster of the Sun, one can only attach probabilities of membership. Bobylev,V.V., Bajkova, A.T., Mylläri, A. & Valtonen,M. 2011, Astronomy Letters 37, 550

  9. Quantification of Posterior Globe Flattening: Methodology Development and Validation

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  10. [Implantation of posterior chamber IOL after traumatic cataract extraction].

    PubMed

    Chen, G L

    1989-09-01

    Traumatic cataracts are often complicated with posterior capsule perforation and opacity to render implantation of posterior chamber IOL difficult. The authors operated on 62 cases using McIntyre's canula and Peyman's vitrophage with satisfactory results. The visual acuity was 0.5 or better in 66%, 0.7 or better in 45%, less than 0.1 in 3 patients because of vitreous opacity and corneal leucoma. In 2 cases associated with aniridia, the IOL was implanted into the capsule bag to obtain visual acuity of 1.2 and 1.0. In 4 patients with intraocular foreign body, the combined operation of foreign body and cataract extraction, vitrectomy, and posterior chamber IOL implantation was performed. PMID:2633900

  11. Reversible posterior leukoencephalopathy syndrome: report of three cases.

    PubMed

    Ozyurek, Hamit; Oguz, Gulben; Ozen, Seza; Akyuz, Canan; Karli Oguz, Kader; Anlar, Banu; Aysun, Sabiha

    2005-12-01

    Reversible posterior leukoencephalopathy syndrome is characterized clinically by headache, abnormalities of mental status and visual perception, and seizures. Despite its diverse causes, common precipitating factors are defined as abrupt elevations of blood pressure, renal decompensation, fluid retention, and immunosuppressive therapy. We report three children with reversible posterior leukoencephalopathy syndrome presenting with generalized seizures and headache. The causes of reversible posterior leukoencephalopathy syndrome were considered to be acute hypertension and immunosuppressive therapy in case 1 with systemic lupus erythematosus, chemotherapy (vincristine and/or actinomycin-D) and hyponatremia in case 2, and acute hypertension in case 3, admitted with a familial Mediterranean fever attack. In light of these cases, we review the literature for the etiology, clinical and laboratory findings, and pathogenetic mechanisms of the disease. PMID:16417849

  12. Endothelin: A novel peptide in the posterior pituitary system

    SciTech Connect

    Yoshizawa, Toshihiro; Kanazawa, Ichiro; Shinmi, Osamu; Kimura, Sadao; Yanagisawa, Masashi; Masaki, Tomoh; Uchiyama, Yasuo ); Giaid, A.; Gibson, S.J.; Polak, J.M. )

    1990-01-26

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

  13. Quantification of Posterior Globe Flattening: Methodology Development and Validationc

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  14. Magnetic Resonance Arthrography of the Glenohumeral Joint: Ultrasonography-Guided Technique Using a Posterior Approach

    PubMed Central

    Ogul, Hayri; Bayraktutan, Ummugulsum; Yildirim, Omer Selim; Suma, Selami; Ozgokce, Mesut; Okur, Adnan; Kantarci, Mecit

    2012-01-01

    Objective: The purpose of this study was to assess the efficacy and feasibility of ultrasound (US)-guided magnetic resonance (MR) arthrography of the glenohumeral joint via a posterior approach. Materials and Methods: Thirty-four patients (18 males and 16 females) who were suspected to have glenohumeral joint pathology were examined using MR arthrography. The patients ranged in age from 21 to 85 years, and the average age was 45±15.9 years. A Toshiba Xario US unit was utilized. Ultrasonography examinations were conducted using a broad-band 5–12 MHz linear array transducer. Gadolinium was injected into the shoulder joint using an 18–20 gauge needle. MR imaging was performed within the first 30 min after the injection. Results: The injection of gadolinium into the shoulder joint was successfully accomplished in all 34 patients. Major contrast media extravasation outside the joint was depicted in only two patients (5.9%). No major complications were encountered. Conclusion: Ultrasonography is an effective alternate guidance technique for the injection of gadolinium into the glenohumeral joint for MR arthrography. US-guided arthrography via a posterior approach to the glenohumeral joint is safe, accurate, well tolerated by patients and easy to perform with minimal training. PMID:25610213

  15. A Catalog of Transit Timing Posterior Distributions for all Kepler Planet Candidate Transit Events

    NASA Astrophysics Data System (ADS)

    Montet, Benjamin Tyler; Becker, Juliette C.; Johnson, John Asher

    2015-12-01

    Kepler has ushered in a new era of planetary dynamics, enabling the detection of interactions between multiple planets in transiting systems for hundreds of systems. These interactions, observed as transit timing variations (TTVs), have been used to find non-transiting companions to transiting systems and to measure masses, eccentricities, and inclinations of transiting planets. Often, physical parameters are inferred by comparing the observed light curve to the result of a photodynamical model, a time-intensive process that often ignores the effects of correlated noise in the light curve. Catalogs of transit timing observations have previously neglected non-Gaussian uncertainties in the times of transit, uncertainties in the transit shape, and short cadence data. Here, I present a catalog of not only times of transit centers, but also posterior distributions on the time of transit for every planet candidate transit event in the Kepler data, developed through importance sampling of each transit. This catalog allows one to marginalize over uncertainties in the transit shape and incorporate short cadence data, the effects of correlated noise, and non-Gaussian posteriors. Our catalog will enable dynamical studies that reflect accurately the precision of Kepler and its limitations without requiring the computational power to model the light curve completely with every integration. I will also present our open-source N-body photodynamical modeling code, which integrates planetary and stellar orbits accounting for the effects of GR, tidal effects, and Doppler beaming.

  16. A Tale of Two Probabilities

    ERIC Educational Resources Information Center

    Falk, Ruma; Kendig, Keith

    2013-01-01

    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.

  17. Essential Probability1 Michael Woodroofe

    E-print Network

    Woodroofe, Michael B.

    Essential Probability1 Michael Woodroofe The University of Michigan 1Copyright c 2013 by Michael Woodroofe #12;2 #12;Contents 1 Combinatorial Probability 5 1.1 The Classical Model Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.4 Problems and Complements

  18. A biomechanical comparison of repair techniques in posterior type II superior labral anterior and posterior (SLAP) lesions.

    PubMed

    Yoo, Jae Chul; Ahn, Jin Hwan; Lee, Sang Hak; Lim, Hong Chul; Choi, Kui Won; Bae, Tae Soo; Lee, Chang Yang

    2008-01-01

    The purpose of this study was to compare the 3 different fixation methods of posterior type superior labral anterior posterior (SLAP) II lesion. Fifteen cadavers were randomly divided into 3 groups to compare the initial strength of 3 different fixation methods in posterior type II SLAP lesions. Group I used 1 anchor for 1-point fixation with a conventional simple suture; group II used 1 anchor passing both limbs through the posterior-superior labrum in a mattress fashion; and group III used 2 anchors for 2-point fixation with conventional simple sutures. Repair failure (2 mm permanent displacement of repaired site) and ultimate failure were measured. The mean load to (clinical) failure was 156 +/- 22 N in group I, 117 +/- 33 N in group II, and 161 +/- 44 N in group III. The mean load to ultimate failure was 198 +/- 6 N in group I, 189 +/- 23 N in group II, and 179 +/- 22 N in group III. The specimen stiffness was equivalent among groups. In mode of failure, clinical failure (more than 2 mm separations) first occurred between the markers on the biceps tendon just above (A) and below (B) compared to other markers, and ultimate failure occurred at the labral-implant interface. A single simple suture anchor repair in posterior type II SLAP seems sufficient to withstand the initial load without clinical failure. A mattress suture, although it anchors the biceps root, seems to be inferior than simple suture technique. PMID:18069010

  19. Morphologic study of posterior articular depression in Schatzker IV fractures.

    PubMed

    Zhai, Qilin; Hu, Chengfang; Xu, Yafeng; Wang, Dan; Luo, Congfeng

    2015-02-01

    The Schatzker classification of tibial plateau fractures is widely accepted. Type IV fractures are medial tibial plateau fractures that are either split off as a wedge fragment or depressed and comminuted. Posterior articular surface depression in Schatzker type IV tibial plateau fractures can be seen as a unique variant that increases the difficulty of reduction of the articular surface. Its morphologic characteristics have not been fully studied, and the incidence is sometimes underestimated. The goal of this study was to evaluate the morphologic characteristics of posterior articular depression in Schatzker type IV fractures based on computed tomography measurements. From January 2009 to December 2011, the medical records, including digital radiologic data, of all patients treated for tibial plateau fracture at the authors' institution were retrospectively analyzed. Articular surface depression deeper than 5 mm was the criterion for study inclusion. The depression depth, precise location of the articular depression center, surface area percentage, and distance of the fracture gap to the depression center were calculated. One hundred fifteen cases of Schatzker type IV fracture were retrieved, and a total of 47.83% (55 of 115) cases had posterior articular surface depression. The average depth of the depressed articular surface was 12.41 mm, the surface area percentage was 20.15% of the entire tibial plateau, and the gap distance from the medial direction was 41.40 mm, 2.8 times longer than that from the posterior direction, which was 14.91 mm. Posterior articular surface depression occurs in nearly half of Schatzker type IV fractures, and the posterior approach provides more direct access to the depression than the medial approach. PMID:25665117

  20. INTRAOCULAR LENS IMPLANTATION IN PEDIATRIC EYES WITH POSTERIOR LENTIGLOBUS

    PubMed Central

    Wilson, M. Edward; Trivedi, Rupal H.

    2006-01-01

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

  1. Spinal Hydatid as a Rare Cause of Posterior Mediastinal Lesion: Understanding Cervicothoracic Sign on Chest Radiography

    PubMed Central

    Aswani, Yashant; Hira, Priya

    2015-01-01

    Summary Background Location of an intrathoracic lesion on chest radiograph is facilitated by application of ‘silhouette sign’. This helps narrow down the differential diagnoses. The list of probable diagnoses reduces further on determination of the density of the lesion. A spinal hydatid presents as a fluid-density posterior mediastinal lesion on chest radiograph with destruction of the vertebral body and preservation of the disc space. Spinal hydatid is, however, rare. Case Report We describe a case of a 30-year-old female with gradual-onset paraperesis since six months. Chest radiograph was suggestive of a posterior mediastinal lesion with fluid density and destruction of D4 vertebra. MRI findings were consistent with spinal hydatid. The patient was started on perioperative benzimidazole therapy with resection of the hydatid cyst. The drug therapy was continued for six months post-operatively. Conclusions A chest radiograph helps localise the site and possible contents of the lesion. It also guides further investigations. MRI is the imaging modality of choice for spinal pathologies causing cord compression including spinal hydatid. Echinococcal involvement of the spine is a rarity but needs to be considered in the differential diagnoses for spinal causes of gradual-onset paraperesis. PMID:26692911

  2. Management of posterior reversible syndrome in preeclamptic women.

    PubMed

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

    2014-01-01

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

  3. Management of Posterior Reversible Syndrome in Preeclamptic Women

    PubMed Central

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

    2014-01-01

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

  4. Rare posterior reversible encephalopathy syndrome in a patient with HIV

    PubMed Central

    Ribeiro, Sofia; Monteiro, Marta; Moreira, Bruno; França, Margarida

    2013-01-01

    Posterior reversible encephalopathy syndrome (PRES) is an uncommon neurological disorder, characterised by the rapid onset of neurological deficits and characteristic neuroimaging findings—cerebral oedema with a typical preference for the posterior white matter. We report a case of a 59-year-old woman with an untreated HIV infection and hypertension with a PRES diagnosis and a rare involvement of the basal ganglia and brainstem, with microhemorrhages. HIV infection, particularly if untreated, is associated with an inflammatory status and therefore endothelial damage and dysfunction that might have an important role in predisposing acute hypertensive crisis and PRES. PMID:24252840

  5. STATISTICS AND PHILOSOPHY OF PROBABILITY

    E-print Network

    Burdzy, Krzysztof "Chris"

    STATISTICS AND PHILOSOPHY OF PROBABILITY -- SIX DEGREES OF SEPARATION Krzysztof Burdzy University of Washington Krzysztof Burdzy Philosophy of probability #12;The search for certainty The search for certainty. On the clash of science and philosophy of probability. Preface, Table of Contents and Introduction

  6. Probability state modeling theory.

    PubMed

    Bagwell, C Bruce; Hunsberger, Benjamin C; Herbert, Donald J; Munson, Mark E; Hill, Beth L; Bray, Chris M; Preffer, Frederic I

    2015-07-01

    As the technology of cytometry matures, there is mounting pressure to address two major issues with data analyses. The first issue is to develop new analysis methods for high-dimensional data that can directly reveal and quantify important characteristics associated with complex cellular biology. The other issue is to replace subjective and inaccurate gating with automated methods that objectively define subpopulations and account for population overlap due to measurement uncertainty. Probability state modeling (PSM) is a technique that addresses both of these issues. The theory and important algorithms associated with PSM are presented along with simple examples and general strategies for autonomous analyses. PSM is leveraged to better understand B-cell ontogeny in bone marrow in a companion Cytometry Part B manuscript. Three short relevant videos are available in the online supporting information for both of these papers. PSM avoids the dimensionality barrier normally associated with high-dimensionality modeling by using broadened quantile functions instead of frequency functions to represent the modulation of cellular epitopes as cells differentiate. Since modeling programs ultimately minimize or maximize one or more objective functions, they are particularly amenable to automation and, therefore, represent a viable alternative to subjective and inaccurate gating approaches. PMID:26012929

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

    E-print Network

    Pat Scott

    2012-10-03

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

  8. Estimation of a benchmark dose in the presence or absence of hormesis using posterior averaging.

    PubMed

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

    2015-03-01

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

  9. Clinical and Radiological Results of Microsurgical Posterior Lumbar Interbody Fusion and Decompression without Posterior Instrumentation for Lateral Recess Stenosis

    PubMed Central

    ?i?man, Lokman; Türkmen, Faik; Efe, Duran; Pekince, O?uzhan; Göncü, Recep Gani; Sever, Cem

    2015-01-01

    Study Design A single-center, retrospective patient review of clinical and radiological outcomes of microsurgical posterior lumbar interbody fusion and decompression, without posterior instrumentation, for the treatment of lateral recess stenosis. Purpose This study documented the clinical and radiological results of microsurgical posterior lumbar interbody fusion and decompression of the lateral recess using interbody cages without posterior instrumentation for the treatment of lateral recess stenosis. Overview of Literature Although microsurgery has some advantages, various complications have been reported following microsurgical decompression, including cage migration, pseudoarthrosis, neurologic deficits, and persistent pain. Methods A total of 34 patients (13 men, 21 women), with a mean age of 56.65±9.1 years (range, 40-77 years) confirmed spinal stability, and preoperative radiological findings of lateral recess stenosis, were included in the study. Interbody polyetheretherketone cages and auto grafts were used in all patients. Posterior instrumentation was not used because of limited resection of the posterior lumbar structures. Preoperative and postoperative radiographs, computed tomography scans, and magnetic resonance imaging were assessed and compared to images taken at the final follow-up. Functional recovery was also evaluated according to the Macnab criteria at the final follow-up. Results The average follow-up time was 35.05±8.65 months (range, 24-46 months). The clinical results, operative time, intraoperative blood loss, and duration of hospital stay were similar to previously published results; the fusion rate (85.2%) was decreased and the migration rate (5.8%) was increased, compared with prior reports. Conclusions Although microsurgery has some advantages, migration and pseudoarthrosis remain challenges to achieving adequate lumbar interbody fusion. PMID:26435789

  10. Some New Twists to Problems Involving the Gaussian Probability Integral

    NASA Technical Reports Server (NTRS)

    Simon, Marvin K.; Divsalar, Dariush

    1997-01-01

    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).

  11. Practical implementation of joint multitarget probabilities

    NASA Astrophysics Data System (ADS)

    Musick, Stanton; Kastella, Keith D.; Mahler, Ronald P. S.

    1998-07-01

    A Joint Multitarget Probability (JMP) is a posterior probability density pT(x1,...,xTZ) that there are T targets (T an unknown number) with unknown locations specified by the multitarget state X equals (x1,...,xT)T conditioned on a set of observations Z. This paper presents a numerical approximation for implementing JMP in detection, tracking and sensor management applications. A problem with direct implementation of JMP is that, if each xt, t equals 1,...,T, is discretized on a grid of N elements, NT variables are required to represent JMP on the T-target sector. This produces a large computational requirement even for small values of N and T. However, when the sensor easily separates targets, the resulting JMP factorizes and can be approximated by a product representation requiring only O(T2N) variables. Implementation of JMP for multitarget tracking requires a Bayes' rule step for measurement update and a Markov transition step for time update. If the measuring sensor is only influenced by the cell it observes, the JMP product representation is preserved under measurement update. However, the product form is not quite preserved by the Markov time update, but can be restored using a minimum discrimination approach. All steps for the approximation can be performed with O(N) effort. This notion is developed and demonstrated in numerical examples with at most two targets in a 1-dimensional surveillance region. In this case, numerical results for detection and tracking for the product approximation and the full JMP are very similar.

  12. Tibialis Anterior Tendon Transfer for Posterior Tibial Tendon Insufficiency.

    PubMed

    Ramanujam, Crystal L; Stapleton, John J; Zgonis, Thomas

    2016-01-01

    The Cobb procedure is useful for addressing stage 2 posterior tibial tendon dysfunction and is often accompanied by a medial displacement calcaneal osteotomy and/or lateral column lengthening. The Cobb procedure can also be combined with selected medial column arthrodesis and realignment osteotomies along with equinus correction when indicated. PMID:26590721

  13. Posterior propriety in objective Bayesian extreme value analyses

    E-print Network

    Guillas, Serge

    and block maxima respectively. For each extreme value distribution we consider objective Bayesian inference. The use of the generalized extreme value (GEV) distribution (Jenkinson, 1955), with distribution functionPosterior propriety in objective Bayesian extreme value analyses Paul J. Northrop and Nicolas

  14. Posterior parietal cortex and the filtering of distractors

    E-print Network

    Robertson, Lynn

    relevant objects, filtering out competing distractors. Neurophysiological studies in animals and brain areas, originating in structures important for attentional control. To test whether the posterior, responses are biased in favor of the target, and the influence of distracting stimuli in the RF is filtered

  15. Approximating Posterior Distributions in Belief Networks using Mixtures

    E-print Network

    Jordan, Michael I.

    Approximating Posterior Distributions in Belief Networks using Mixtures Christopher M. Bishop Neil Birmingham, B4 7ET, U.K. Tommi Jaakkola Michael I. Jordan Center for Biological and Computational Learning likelihood learning for Bayesian networks requires the evaluation of the likelihood function P (V j`) where V

  16. Suture Bridge Fixation Technique for Posterior Cruciate Ligament Avulsion Fracture

    PubMed Central

    Lee, Kwang Won; Lee, Gyu Sang; Choy, Won Sik

    2015-01-01

    We presented a surgical technique including a suture bridge technique with relatively small incision for the reduction and fixation of posterior ligament avulsion fractures. A suture anchor was used to hold the avulsed fragment and a knotless anchor was used to continuously compress the bony fragment into the fracture site, thereby maintaining reduction during healing. PMID:26640635

  17. Bilateral Congenital Posterior Capsular Defects and Ectopic Cataracts.

    PubMed

    Tandon, Anika K; Oltra, Erica Z; Velez, Federico G

    2015-01-01

    Preexisting posterior capsular defects are rare and can be associated with infantile cataracts. The authors review possible etiologies of this condition and emphasize the importance of cautious preoperative planning and surgery. [J Pediatr Ophthalmol Strabismus. 2015;52:e48-e51.]. PMID:26431560

  18. Behavioral/Systems/Cognitive Visuotopic Organization of Macaque Posterior Parietal

    E-print Network

    Kastner, Sabine

    Behavioral/Systems/Cognitive Visuotopic Organization of Macaque Posterior Parietal Cortex, Princeton, New Jersey 08540 Macaque anatomy and physiology studies have revealed multiple visual areas- ping paradigm in the awake macaque, a large-scale visuotopic organization along lateral portions of PPC

  19. Probability workshop to be better in probability topic

    NASA Astrophysics Data System (ADS)

    Asmat, Aszila; Ujang, Suriyati; Wahid, Sharifah Norhuda Syed

    2015-02-01

    The purpose of the present study was to examine whether statistics anxiety and attitudes towards probability topic among students in higher education level have an effect on their performance. 62 fourth semester science students were given statistics anxiety questionnaires about their perception towards probability topic. Result indicated that students' performance in probability topic is not related to anxiety level, which means that the higher level in statistics anxiety will not cause lower score in probability topic performance. The study also revealed that motivated students gained from probability workshop ensure that their performance in probability topic shows a positive improvement compared before the workshop. In addition there exists a significance difference in students' performance between genders with better achievement among female students compared to male students. Thus, more initiatives in learning programs with different teaching approaches is needed to provide useful information in improving student learning outcome in higher learning institution.

  20. Advances in the Measurement of Atomic Transition Probabilities

    NASA Astrophysics Data System (ADS)

    O'Brian, Thomas Raymond

    The technology for measuring absolute atomic transition probabilities is extended. Radiative lifetimes are measured by time-resolved laser-induced fluorescence on a slow atomic beam generated by a versatile hollow cathode discharge source. The radiative lifetimes are free from systematic error at the five percent level. Combined with branching fractions measured with emission or absorption sources, the lifetimes result in absolute transition probabilities usually accurate to 5-10 %. Three new developments in the lifetime and branching fraction technique are reported. Radiative lifetimes for 186 levels in neutral iron are measured, with the energy of the upper levels densely spanning the entire excitation range of neutral iron. Combined with branching fractions measured in emission with Fourier transform spectrophotometry, the level lifetimes directly yield absolute transition probabilities for 1174 transitions. An additional 640 transition probabilities are determined by interpolating level populations in an emission source. The dense energy spacing of the levels with directly measured lifetimes permits accurate population interpolation despite departures from local thermodynamic equilibrium. This technique has the potential to permit accurate absolute transition probability measurements for essentially every classified line in a spectrum. Radiative lifetime measurements are extended into the vacuum ultraviolet with a continuously tunable vacuum ultraviolet laser based on stimulated anti-Stokes Raman scattering. When used with the hollow cathode atomic beam source, accurate lifetimes are measured for 47 levels in neutral silicon and 8 levels in neutral boron, primarily in the vacuum ultraviolet spectral region. Transition probabilities are reported for many lines connected to these upper levels, using previously measured or calculated branching fractions. The hollow cathode beam source is developed for use with refractory non-metals. Intense atomic beams of boron, carbon, and silicon are generated and level lifetimes measured for these elements in the visible, ultraviolet, and vacuum ultraviolet spectral regions.

  1. Probability (Math/Stat 511)

    E-print Network

    Sharpley, Robert

    the definition of a probability P on S. b.) Give the definition of a random variable X on an outcome space S. 2 S with a probability P. a.) Give the definition for A and B to be independent events. b.) If A and B are independent% of the population under investigation is known to have the disease, what is the probability that a patient from

  2. Probability Surveys, Conditional Probability, and Ecological Risk Assessment

    EPA Science Inventory

    We show that probability-based environmental resource monitoring programs, such as the U.S. Environmental Protection Agency’s (U.S. EPA) Environmental Monitoring and Assessment Program, and conditional probability analysis can serve as a basis for estimating ecological risk over ...

  3. DREAM(D): an adaptive markov chain monte carlo simulation algorithm to solve discrete, noncontinuous, posterior parameter estimation problems

    NASA Astrophysics Data System (ADS)

    Vrugt, J. A.

    2011-04-01

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

  4. Ultrahighly accurate 3D profilometer

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Hideki; Yoshizumi, Keiichi; Takeuchi, Hiroyuki

    2005-02-01

    We have developed an Ultrahigh-Accurate 3-D Profilometer (UA3P), which, using a new, in-house-developed atomic force probe, has an accuracy of 10 nm. It is capable of measuring corners as small as 2 micro meter in radius and can cover an area up to 400 x 400 x 90 (mm), providing a powerful boost to nano-level processing. A commercial product was introduced in 1994. Examples of the key components made possible by this technology include aspherical lenses (used for a Blu-ray Disc device, a next-generation DVD, digital cameras, cellular phones, optical communications), free form lenses (used for frennel lens common to CD and DVD, laser printer lens, multi focus glass lens, cubic phase plate to extend depth of focus), gigabit semiconductor wafers, hard discs, air conditioner scroll vanes, DVC cylinders. The premiere ultra high-precision three-dimensional profilometer delivers superb performance using a variety of micro-measurements for a wide range of applications.

  5. The relationship between species detection probability and local extinction probability

    USGS Publications Warehouse

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

    2004-01-01

    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.

  6. What you need to know about ossification of the posterior longitudinal ligament to optimize cervical spine surgery: A review

    PubMed Central

    Epstein, Nancy E.

    2014-01-01

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

  7. Facilitating normative judgments of conditional probability: frequency or nested sets?

    PubMed

    Yamagishi, Kimihiko

    2003-01-01

    Recent probability judgment research contrasts two opposing views. Some theorists have emphasized the role of frequency representations in facilitating probabilistic correctness; opponents have noted that visualizing the probabilistic structure of the task sufficiently facilitates normative reasoning. In the current experiment, the following conditional probability task, an isomorph of the "Problem of Three Prisoners" was tested. "A factory manufactures artificial gemstones. Each gemstone has a 1/3 chance of being blurred, a 1/3 chance of being cracked, and a 1/3 chance of being clear. An inspection machine removes all cracked gemstones, and retains all clear gemstones. However, the machine removes 1/2 of the blurred gemstones. What is the chance that a gemstone is blurred after the inspection?" A 2 x 2 design was administered. The first variable was the use of frequency instruction. The second manipulation was the use of a roulette-wheel diagram that illustrated a "nested-sets" relationship between the prior and the posterior probabilities. Results from two experiments showed that frequency alone had modest effects, while the nested-sets instruction achieved a superior facilitation of normative reasoning. The third experiment compared the roulette-wheel diagram to tree diagrams that also showed the nested-sets relationship. The roulette-wheel diagram outperformed the tree diagrams in facilitation of probabilistic reasoning. Implications for understanding the nature of intuitive probability judgments are discussed. PMID:12693194

  8. The Probabilities of Conditionals Revisited

    ERIC Educational Resources Information Center

    Douven, Igor; Verbrugge, Sara

    2013-01-01

    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…

  9. SUBJECTIVE PROBABILITY THE REAL THING

    E-print Network

    Fienberg, Stephen E.

    SUBJECTIVE PROBABILITY THE REAL THING Richard Jeffrey c 2002 November 4, 2002 #12;1 Contents, 1 1 on alien probabilities for diagnoses, 62 3.4.2 Updating on alien factors for diagnoses, 62 3.5 Softcore, in which the colors are all the real numbers from 0 to 1. The question of the precise relationship between

  10. J. FRANKLIN RESURRECTING LOGICAL PROBABILITY

    E-print Network

    Franklin, James

    , or the manner of its throwing. By contrast, The probability that the big bang hypothesis is true, given present, or "objective Bayesianism" ­ the theory that (some) probabilities are strictly logical degrees of partial degree of logical support that evidence e gives to hypothesis h. The theory has an obvious initial

  11. Improving Aggregated Forecasts of Probability

    E-print Network

    Osherson, Daniel

    include "President Obama will be re- elected in 2012", "Obama will be re-elected if the U.S. unemploy, a user might be asked questions about simple events such as "What is the probability that Obama wins Indiana?" and also questions about complex events like "What is the probability that Obama wins Vermont

  12. THE DISCOVERY OF ALGORITHMIC PROBABILITY

    E-print Network

    Solomonoff, Ray

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

  13. THE DISCOVERY OF ALGORITHMIC PROBABILITY

    E-print Network

    Solomonoff, Ray

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

  14. Decision analysis with approximate probabilities

    NASA Technical Reports Server (NTRS)

    Whalen, Thomas

    1992-01-01

    This paper concerns decisions under uncertainty in which the probabilities of the states of nature are only approximately known. Decision problems involving three states of nature are studied. This is due to the fact that some key issues do not arise in two-state problems, while probability spaces with more than three states of nature are essentially impossible to graph. The primary focus is on two levels of probabilistic information. In one level, the three probabilities are separately rounded to the nearest tenth. This can lead to sets of rounded probabilities which add up to 0.9, 1.0, or 1.1. In the other level, probabilities are rounded to the nearest tenth in such a way that the rounded probabilities are forced to sum to 1.0. For comparison, six additional levels of probabilistic information, previously analyzed, were also included in the present analysis. A simulation experiment compared four criteria for decisionmaking using linearly constrained probabilities (Maximin, Midpoint, Standard Laplace, and Extended Laplace) under the eight different levels of information about probability. The Extended Laplace criterion, which uses a second order maximum entropy principle, performed best overall.

  15. Probability and complex quantum trajectories

    SciTech Connect

    John, Moncy V.

    2009-01-15

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

  16. Laser-assisted in situ keratomileusis posterior ablation platform.

    PubMed

    Maldonado, Miguel J

    2005-07-01

    A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery. PMID:16009842

  17. Extended indications for robotic surgery for posterior mediastinal tumors.

    PubMed

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

    2012-06-01

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

  18. Distichiasis: management with cryotherapy to the posterior lamella.

    PubMed Central

    O'Donnell, B A; Collin, J R

    1993-01-01

    Distichiasis is the congenital condition of partial or complete accessory rows of eyelashes which exit from the posterior lid margin at or near the meibomian gland orifices. A series of 24 patients with distichiasis is presented with clinical features and results of treatment. The treatment modes of epilation, lid margin cryotherapy, or eyelid splitting cryotherapy to the posterior lamella are evaluated. The latter was found to effectively relieve symptoms without retreatment in 87% patients. Keratinisation of the lid margin was found at long term follow up in a few cases and retinoic acid has been used successfully in the treatment of this. Two previously unreported associations of distichiasis are Pierre Robin syndrome and idiopathic eyelid oedema. A family history of distichiasis was found in 50% patients, and of distichiasis with lymphoedema in 30%. Images PMID:8318465

  19. Superior labrum anterior to posterior lesions and the superior labrum.

    PubMed

    Rowbotham, Emma L; Grainger, Andrew J

    2015-07-01

    The fibrocartilaginous glenoid labrum contributes to shoulder stability and provides attachment for the long head of biceps tendon and the glenohumeral ligaments. The superior site of attachment of the long head of biceps (biceps anchor) represents a site of injury to the superior labrum where tearing may extend into the biceps tendon as well as anterior and/or posterior to the biceps anchor. Such tears are known as superior labrum anterior and posterior (SLAP) tears and are a cause of both shoulder instability and pain. SLAP tears are frequently seen in those undertaking repetitive frequent overarm activity such as throwing athletes and swimmers. This article reviews the mechanisms and types of SLAP tears and their imaging appearances. It also discusses associated injuries and pitfalls in diagnosing these injuries. PMID:26021587

  20. Clinical Characteristics of Posterior and Lateral Semicircular Canal Dehiscence.

    PubMed

    Spasic, Marko; Trang, Andy; Chung, Lawrance K; Ung, Nolan; Thill, Kimberly; Zarinkhou, Golmah; Gopen, Quinton S; Yang, Isaac

    2015-12-01

    The objective of this study was to evaluate the characteristic symptoms of and treatments for lateral semicircular canal dehiscence (LSCD) and posterior semicircular canal dehiscence (PSCD) and its proposed mechanism. A dehiscence acquired in any of the semicircular canals may evoke various auditory symptoms (autophony and inner ear conductive hearing loss) or vestibular symptoms (vertigo, the Tullio phenomenon, and Hennebert sign) by creating a "third mobile window" in the bone that enables aberrant communication between the inner ear and nearby structures. A PubMed search was performed using the keywords lateral, posterior, and semicircular canal dehiscence to identify all relevant cases. Our data suggest that PSCD, although clinically rare, is most likely associated with a high-riding jugular bulb and fibrous dysplasia. Patients may experience auditory manifestations that range from mild conductive to extensive sensorineural hearing loss. LSCD is usually associated with chronic otitis media with cholesteatoma. PMID:26682120

  1. Evaluation of arthroscopic treatment of posterior shoulder instability

    PubMed Central

    Garcia, José Carlos; Maia, Lucas Russo; Fonseca, Juliano Rocha; Zabeu, José Luís Amim; Garcia, Jesely Pereira Myrrha

    2015-01-01

    OBJECTIVE: To provide data for the analysis of arthroscopy as a method of surgical treatment for shoulder and discuss its actual indications and preliminary results. METHODS: We evaluated 15 patients submitted to reverse Bankart arthroscopic surgery. We used the UCLA (University of California at Los Angeles) score to measure the results before surgery and 12 months thereafter. RESULTS: The average UCLA score changed from 26.67±0.25 (SD 0.97) before surgery to 34.20±0.53 (SD 2.04) after surgery. The effectiveness of surgery was 93%. In five cases loose bodies were found. A patient undergoing remplissage was evaluated separately. The data did not change after 24 months post-surgery. CONCLUSION: The arthroscopic treatment of posterior shoulder instability and posterior dislocation of the shoulder has been proved feasible and results in our series followed the same trends as in the literature. Level of Evidence III, Transversal Retrospective Study. PMID:26207089

  2. [A bilateral posterior shoulder dislocation caused by humeral head osteonecrosis].

    PubMed

    Barbier, O; Van Gaver, E; Rigal, S

    2010-02-01

    We report a case of simultaneous bilateral posterior shoulders dislocations in a 46-year-old male with antecedent of high-dose corticotherapy. The mechanism was non-traumatic after a contraction of the sub scapularis muscle in internal rotation. The interscapular pain was not initially diagnosed although a tomodensitometry was realized to eliminate a cardiovascular emergency. After reduction, the shoulders were unstable and the MRI showed an osteonecrosis of the humeral heads. The patient underwent surgery with an iliac spongy bone graft in the humeral nick. At 3 months, there was no recurrence and mobilities were good. Bilateral posterior shoulders dislocations are unusual and it is the first case of non-traumatic dislocation. Aetiology are often epilepsy, electrocution, and extreme traumatism. Diagnosis is often misrecognized and the treatment is not well codified. PMID:20093062

  3. Complications associated with posterior and transforaminal lumbar interbody fusion.

    PubMed

    Chrastil, Jesse; Patel, Alpesh A

    2012-05-01

    Posterior lumbar interbody fusion and transforaminal lumbar interbody fusion are commonly performed to obtain a 360° arthrodesis through a posterior-only approach. These techniques are currently used in the management of spondylolisthesis, degenerative scoliosis, pseudarthrosis, recurrent disk herniation, and chronic low back pain with associated degenerative disk disease. Several adverse events have been described, including intraoperative neurologic injury, implant migration or subsidence, dural tears, infection, heterotopic ossification, BMP-related radiculitis, and osteolysis. Although the use of newer materials (eg, bone morphogenetic proteins) and procedures (eg, minimally invasive surgery) is on the rise, they are associated with unique concerns. Understanding the potential adverse events and steps that can be taken to prevent, detect, and manage complications is critical in patient counseling and perioperative decision making. PMID:22553100

  4. Superior Labral Anterior Posterior Lesions of the Shoulder

    PubMed Central

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

    2013-01-01

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

  5. Posterior dislocation of the hip while playing basketball.

    PubMed

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

    1998-12-01

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

  6. Henoch-Schönlein Purpura with Posterior Reversible Encephalopathy Syndrome.

    PubMed

    Stefek, Bryan; Beck, Michael; Ioffreda, Michael; Gardner, Lyndsay; Stefanski, Michael

    2015-11-01

    Henoch-Schönlein purpura is a common small-vessel vasculitis that presents in children as nonthrombocytopenic, nontender, and palpable purpura, arthritis/arthralgia, and abdominal pain. Central nervous system involvement is a reported, but likely, under-recognized complication. We present an 8-year-old boy with Henoch-Schönlein purpura and posterior reversible encephalopathy syndrome, after proposed mechanism and treatment considerations. PMID:26323197

  7. Transient reduction in venous susceptibility during posterior reversible encephalopathy syndrome.

    PubMed

    Ollivier, Morgan; Wanono, Emmanuelle; Leclercq, Delphine; Domont, Fanny; Trunet, Stéphanie; Dormont, Didier; Bertrand, Anne

    2015-11-15

    We report a case of posterior reversible encephalopathy syndrome (PRES) in which followed-up MRI demonstrated a transient reduction in venous signal on initial SWAN images. The progressive normalization of venous signal on D10 and D40 imaging paralleled the progressive decrease of hyperperfusion on CBF images. Decreased venous susceptibility has never been reported in PRES; it relates most likely to a transient BOLD effect induced by brain hyperperfusion. PMID:26434616

  8. Subjective probability intervals: how to reduce overconfidence by interval evaluation.

    PubMed

    Winman, Anders; Hansson, Patrik; Juslin, Peter

    2004-11-01

    Format dependence implies that assessment of the same subjective probability distribution produces different conclusions about over- or underconfidence depending on the assessment format. In 2 experiments, the authors demonstrate that the overconfidence bias that occurs when participants produce intervals for an uncertain quantity is almost abolished when they evaluate the probability that the same intervals include the quantity. The authors successfully apply a method for adaptive adjustment of probability intervals as a debiasing tool and discuss a tentative explanation in terms of a naive sampling model. According to this view, people report their experiences accurately, but they are naive in that they treat both sample proportion and sample dispersion as unbiased estimators, yielding small bias in probability evaluation but strong bias in interval production. PMID:15521796

  9. Effect of four different intraocular lenses on posterior capsule opacification

    PubMed Central

    Duman, Rahmi; Karel, Fatih; Özyol, Pelin; Ate?, Can

    2015-01-01

    AIM To evaluate the impact of 4 different intraocular lenses (IOLs) on posterior capsule opacification (PCO) by comparing the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy rates. METHODS This retrospective study included 4970 eyes of 4013 cataract patients who underwent phacoemulsification and IOL implantation between January 2000 and January 2008 by the same surgeon at one clinic. Four different IOLs were assessed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. RESULTS An Nd:YAG laser posterior capsulotomy was performed in 153 (3.07%) of the 4970 eyes. The mean follow-up time was 84mo for all of the IOL groups. The percentage of eyes developing PCO was significantly greater for the acrylic hydrophilic IOLs than for the hydrophobic IOLs, although eyes with acrylic hydrophilic IOLs did not require Nd:YAG laser capsulotomy as soon as eyes with acrylic hydrophobic IOLs. There was no difference between the long-term PCO rates when 1- and 3-piece acrylic hydrophobic IOLs were compared or when IOLs made of the same material but with different haptic angles were compared. CONCLUSION In this study, eyes with acrylic hydrophilic IOLs were more likely to develop PCO than those with acrylic hydrophobic IOLs. The lens design (1-piece versus 3-piece and varying haptic angles) did not affect the PCO rate. PMID:25709920

  10. Intensity-Modulated Arc Therapy for Pediatric Posterior Fossa Tumors

    SciTech Connect

    Beltran, Chris; Gray, Jonathan; Merchant, Thomas E.

    2012-02-01

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

  11. The Great Imitator: Ocular Syphilis Presenting as Posterior Uveitis

    PubMed Central

    Kuo, Alan; Ziaee, Saba M.; Hosseini, Hamid; Voleti, Vinod; Schwartz, Steven D.; Kim, Nam U.; Ge, Phillip S.

    2015-01-01

    Patient: Female, 34 Final Diagnosis: Ocular syphilis Symptoms: Painful unilateral vision loss Medication: Benzylpenicillin Clinical Procedure: Lumbar puncture Specialty: Infectious Diseases • Ophthalmology Objective: Rare disease Background: Syphilis is often known as the “Great Imitator”. The differential diagnosis of posterior uveitis is broad with ocular syphilis being particularly challenging to diagnose as it presents similarly to other ocular conditions such as acute retinal necrosis. Case Report: A 34-year-old woman with multiple sexual partners over the past few years presented with painful and progressively worsening unilateral vision loss for 2 weeks. Several months prior, she had reported non-specific symptoms of headache and diffuse skin rash. Despite treatment with oral acyclovir for 3 weeks, her vision progressively declined, and she was referred to the university ophthalmology clinic for further evaluation. On examination, there was concern for acute retinal necrosis and she was empirically treated with parenteral acyclovir while awaiting further infectious disease study results. Workup ultimately revealed ocular syphilis, and neurosyphilis was additionally confirmed with cerebrospinal fluid studies. Treatment with intravenous penicillin was promptly initiated with complete visual recovery. Conclusions: Ocular syphilis varies widely in presentation and should be considered in all patients with posterior uveitis, especially with a history of headache and skin rashes. However, given that acute retinal necrosis is a more common cause of posterior uveitis and can rapidly result in permanent vision loss, it should be empirically treated whenever it is suspected while simultaneous workup is conducted to evaluate for alternative diagnoses. PMID:26151369

  12. Microscopic Posterior Transdural Resection of Cervical Retro-Odontoid Pseudotumors.

    PubMed

    Fujiwara, Yasushi; Manabe, Hideki; Sumida, Tadayoshi; Tanaka, Nobuhiro; Hamasaki, Takahiko

    2015-12-01

    Retro-odontoid pseudotumors are noninflammatory masses formed posterior to the odontoid process. Because of their anatomy, the optimal surgical approach for resecting pseudotumors is controversial. Conventionally, 3 approaches are used: the anterior transoral approach, the lateral approach, and the posterior extradural approach; however, each approach has its limitations. The posterior extradural approach is the most common; however, it remains challenging due to severe epidural veins. Although regression of pseudotumors after fusion surgery has been reported, direct decompression and a pathologic diagnosis are ideal when the pseudotumor is large. We therefore developed a new microscopic surgical technique; transdural resection. After C1 laminectomy, the dorsal and ventral dura was incised while preserving the arachnoid. Removal of the pseudotumor was performed and both of the dura were repaired. The patient's clinical symptoms subsequently improved and the pathologic findings showed degenerative fibrocartilaginous tissue. In addition, no neurological deterioration, central spinal fluid leakage, or arachnoiditis was observed. Currently, the usefulness of the transdural approach has been reported for cervical and thoracic disk herniation. According to our results, the transdural approach is recommended for resection of retro-odontoid pseudotumors because it enables direct decompression of the spinal cord and a pathologic diagnosis. PMID:26544168

  13. Features of infratentorial-predominant posterior reversible encephalopathy syndrome.

    PubMed

    Fitzgerald, Ryan T; Samant, Rohan S; Kumar, Manoj; Van Hemert, Rudy; Angtuaco, Edgardo J

    2015-12-01

    Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic process that typically occurs in the setting of immune dysregulation. In contrast to the characteristic pattern involving parieto-occipital and posterior frontal regions, predominant involvement of the infratentorial brain occurs in a minority of PRES patients. We examined six patients with infratentorial predominant posterior reversible encephalopathy syndrome (IPPRES) relative to those with typical PRES in terms of clinical factors of toxicity and outcomes. We review the current understanding of PRES pathophysiology. An institutional database of PRES patients was created through an IRB-approved search of the electronic record from 2007 to 2012. MR images were reviewed and classified by two neuro radiologists. Clinical data including laboratory data, blood pressure, and discharge outcome were collected through review of existing electronic medical records. Characteristics of the two groups were compared. Six cases among 80 PRES patients displayed an atypical distribution of signal abnormality predominantly involving the infratentorial brain. In IPPRES patients, signal abnormalities within the supratentorial brain, when present, showed a predominantly central distribution rather than the typical peripheral distribution. IPPRES patients showed higher rates of extreme hypertension, renal dysfunction, abnormal serum calcium, and abnormal serum magnesium relative to typical PRES patients. Outcomes were similar between the two groups. In our small series, IPPRES differs from typical PRES patients not only in the distribution of imaging abnormalities but also in rates of extreme hypertension and several laboratory indices. Despite these differences, clinical outcome in the IPPRES group was similar to that of typical PRES. PMID:25605260

  14. Microscopic Posterior Transdural Resection of Cervical Retro-Odontoid Pseudotumors

    PubMed Central

    Manabe, Hideki; Sumida, Tadayoshi; Tanaka, Nobuhiro; Hamasaki, Takahiko

    2015-01-01

    Retro-odontoid pseudotumors are noninflammatory masses formed posterior to the odontoid process. Because of their anatomy, the optimal surgical approach for resecting pseudotumors is controversial. Conventionally, 3 approaches are used: the anterior transoral approach, the lateral approach, and the posterior extradural approach; however, each approach has its limitations. The posterior extradural approach is the most common; however, it remains challenging due to severe epidural veins. Although regression of pseudotumors after fusion surgery has been reported, direct decompression and a pathologic diagnosis are ideal when the pseudotumor is large. We therefore developed a new microscopic surgical technique; transdural resection. After C1 laminectomy, the dorsal and ventral dura was incised while preserving the arachnoid. Removal of the pseudotumor was performed and both of the dura were repaired. The patient’s clinical symptoms subsequently improved and the pathologic findings showed degenerative fibrocartilaginous tissue. In addition, no neurological deterioration, central spinal fluid leakage, or arachnoiditis was observed. Currently, the usefulness of the transdural approach has been reported for cervical and thoracic disk herniation. According to our results, the transdural approach is recommended for resection of retro-odontoid pseudotumors because it enables direct decompression of the spinal cord and a pathologic diagnosis. PMID:26544168

  15. U-shaped Osteotomy Around the Descending Palatine Artery to Prevent Posterior Osseous Interference for Superior/Posterior Repositioning of the Maxilla in Le Fort I Osteotomy.

    PubMed

    Omura, Susumu; Iwai, Toshinori; Honda, Koji; Shibutani, Naoki; Fujita, Koichi; Yamashita, Yosuke; Takasu, Hikaru; Murata, Shogo; Tohnai, Iwai

    2015-07-01

    In maxillary orthognathic surgery, superior repositioning of the maxilla is sometimes difficult, and removal of bony interference, especially around the descending palatine artery (DPA), is very time-consuming in cases of severe maxillary impaction. Posterior repositioning of the maxilla for removal of bony interference between the posterior maxilla and the pterygoid process is also technically difficult. Because the most common site of hemorrhage in Le Fort I osteotomy is the posterior maxilla, this bone removal is a source of frustration for surgeons in DPA injury. When the DPA is injured during bone removal and ligation is performed, aseptic necrosis of the maxilla may occur. Therefore, a simple and safe method for maxillary superior/posterior repositioning is required to remove osseous interference around the DPA. The authors describe here U-shaped osteotomy around the DPA to prevent posterior osseous interference for superior/posterior repositioning of the maxilla in Le Fort I osteotomy. PMID:26106994

  16. Posterior corneal curvature changes following Refractive Small Incision Lenticule Extraction

    PubMed Central

    Ganesh, Sri; Patel, Utsav; Brar, Sheetal

    2015-01-01

    Purpose To compare the posterior corneal curvature changes, in terms of corneal power and asphercity, following Refractive Small Incision Lenticule Extraction (ReLEx SMILE) procedure for low, moderate, and high myopia. Methods This retrospective, non randomized, comparative, interventional trial; included 52 eyes of 26 patients, divided in three groups: low myopia (myopia ?3 D [diopters] spherical equivalent [SE]), moderate myopia (myopia >3 D and <6 D SE), and high myopia (myopia ?6 D SE). All patients were treated for myopia and myopic astigmatism using ReLEx SMILE. The eyes were examined pre-operatively and 3 months post-operatively using SCHWIND SIRIUS, a three-dimensional rotating Scheimpflug camera with a Placido disc topographer to assess corneal changes with regard to keratometric power and asphericity of the cornea. Results A statistically significant increase in mean keratometric power in the 3, 5, and 7 mm zones of the posterior corneal surface compared with its pre-ReLEx SMILE value was detected after 3 months in the moderate myopia group (pre-operative [pre-op] ?6.14±0.23, post-operative [post-op] ?6.29±0.22, P<0.001) and high myopia group (pre-op ?6.19±0.16, post-op ?6.4±0.18, P<0.001), but there was no significant change in keratometric power of the posterior surface in the low myopia group (pre-op ?5.87±0.17, post-op ?6.06±0.29, P=0.143). Asphericity (Q-value) of the posterior surface changed significantly (P<0.001) after ReLEx SMILE in the moderate myopia group in the 3, 5, and 7 mm zones, and in the high myopia group in the 3 and 7 mm zones; but there was no significant change in the Q-value in the low myopia group in all three zones (pre-op 0.23±0.43, post-op ?0.40±0.71, P=0.170), and in the high myopia group in the 5 mm zone (P=0.228). Conclusion ReLEx SMILE causes significant changes in posterior corneal keratometric power and asphericity in moderate and high myopia, but the effect is subtle and insignificant in low myopia. PMID:26229428

  17. Arthroscopic posterior cruciate ligament reconstruction with allograft versus autograft

    PubMed Central

    Sun, Xiujiang; Zhang, Jianfeng; Qu, Xiaoyi

    2015-01-01

    Introduction The aim of the study was to compare and analyze retrospectively the outcomes of arthroscopic posterior cruciate ligament reconstruction with autograft versus allograft. Material and methods Seventy-one patients who underwent arthroscopic posterior cruciate ligament reconstruction with an autograft or allograft met our inclusion criteria. There were 36 patients in the autograft group and 35 patients in the allograft group. All the patients were evaluated by physical examination and a functional ligament test. Comparative analysis was done in terms of operation time, incision length, fever time, postoperative infection rate, incidence of numbness and dysesthesia around the incision, as well as a routine blood test. Results The average follow-up of the autograft group was 3.2 ±0.2 years and that of the allograft group was 3.3 ±0.6 years; there was no significant difference (p > 0.05). No differences existed in knee range of motion, Lysholm scores, International Knee Documentation Committee standard evaluation form and Tegner activity score at final follow-up (p > 0.05), except that patients in the allograft group had a shorter operation time and incision length and a longer fever time (p < 0.05). We found a difference in posterior drawer test and KT-2000 arthrometer assessment (p < 0.05). The posterior tibia displacement averaged 3.8 ±1.5 mm in the autograft group and 4.8 ±1.7 mm in the allograft group (p < 0.05). The incidence of numbness and dysesthesia around the incision in the autograft group was higher than that in the allograft group (p < 0.05). There was no infection postoperatively. The white blood cells and neutrophils in the allograft group increased more than those in the autograft group postoperatively (p < 0.05). Conclusions Both groups of patients had satisfactory outcomes after the operation. However, in the instrumented posterior laxity test, the autograft gave better results than the allograft. No differences in functional scores were found. PMID:25995757

  18. Probable Inference and Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Grandy, W. T.

    2009-12-01

    In its current very successful interpretation the quantum theory is fundamentally statistical in nature. Although commonly viewed as a probability amplitude whose (complex) square is a probability, the wavefunction or state vector continues to defy consensus as to its exact meaning, primarily because it is not a physical observable. Rather than approach this problem directly, it is suggested that it is first necessary to clarify the precise rôle of probability theory in quantum mechanics, either as applied to, or as an intrinsic part of the quantum theory. When all is said and done the unsurprising conclusion is that quantum mechanics does not constitute a logic and probability unto itself, but adheres to the long-established rules of classical probability theory while providing a means within itself for calculating the relevant probabilities. In addition, the wavefunction is seen to be a description of the quantum state assigned by an observer based on definite information, such that the same state must be assigned by any other observer based on the same information, in much the same way that probabilities are assigned.

  19. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  20. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  1. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  2. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  3. 21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The...

  4. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  5. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  6. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  7. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  8. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  9. Bipolar Posterior Deltoid Transfer for Massive Rotator Cuff Tears: A Report on 2 Patients

    PubMed Central

    2015-01-01

    Summary: A transfer of the posterior deltoid innervated by the posterior branch of the axillary nerve and vascularized by the posterior circumflex humeral artery is described for irreparable tears of the supra- and infraspinatus muscle tendons. Functionally useful abduction and flexion were restored in 2 patients. PMID:26090280

  10. Definition of the Neutrosophic Probability

    NASA Astrophysics Data System (ADS)

    Smarandache, Florentin

    2014-03-01

    Neutrosophic probability (or likelihood) [1995] is a particular case of the neutrosophic measure. It is an estimation of an event (different from indeterminacy) to occur, together with an estimation that some indeterminacy may occur, and the estimation that the event does not occur. The classical probability deals with fair dice, coins, roulettes, spinners, decks of cards, random works, while neutrosophic probability deals with unfair, imperfect such objects and processes. For example, if we toss a regular die on an irregular surface which has cracks, then it is possible to get the die stuck on one of its edges or vertices in a crack (indeterminate outcome). The sample space is in this case: {1, 2, 3, 4, 5, 6, indeterminacy}. So, the probability of getting, for example 1, is less than 1/6. Since there are seven outcomes. The neutrosophic probability is a generalization of the classical probability because, when the chance of determinacy of a stochastic process is zero, these two probabilities coincide. The Neutrosophic Probability that of an event A occurs is NP (A) = (ch (A) , ch (indetA) , ch (A ?)) = (T , I , F) , where T , I , F are subsets of [0,1], and T is the chance that A occurs, denoted ch(A); I is the indeterminate chance related to A, ch(indetermA) ; and F is the chance that A does not occur, ch (A ?) . So, NP is a generalization of the Imprecise Probability as well. If T, I, and F are crisp numbers then: - 0 <= T + I + F <=3+ . We used the same notations (T,I,F) as in neutrosophic logic and set.

  11. Dinosaurs, Dinosaur Eggs, and Probability.

    ERIC Educational Resources Information Center

    Teppo, Anne R.; Hodgson, Ted

    2001-01-01

    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)

  12. The Probabilities of Unique Events

    PubMed Central

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

    2012-01-01

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

  13. Outage probability at finite SNR

    E-print Network

    Akçaba, Cemal

    2004-01-01

    In this thesis, we present a technique to reduce the outage probability of a single user multiple input multiple output (MIMO) channel when a sub-optimal transceiver architecture is used. We show that in slow-fading ...

  14. Logic, probability, and human reasoning.

    PubMed

    Johnson-Laird, P N; Khemlani, Sangeet S; Goodwin, Geoffrey P

    2015-04-01

    This review addresses the long-standing puzzle of how logic and probability fit together in human reasoning. Many cognitive scientists argue that conventional logic cannot underlie deductions, because it never requires valid conclusions to be withdrawn - not even if they are false; it treats conditional assertions implausibly; and it yields many vapid, although valid, conclusions. A new paradigm of probability logic allows conclusions to be withdrawn and treats conditionals more plausibly, although it does not address the problem of vapidity. The theory of mental models solves all of these problems. It explains how people reason about probabilities and postulates that the machinery for reasoning is itself probabilistic. Recent investigations accordingly suggest a way to integrate probability and deduction. PMID:25770779

  15. Probability interpretations of intraclass reliabilities.

    PubMed

    Ellis, Jules L

    2013-11-20

    Research where many organizations are rated by different samples of individuals such as clients, patients, or employees frequently uses reliabilities computed from intraclass correlations. Consumers of statistical information, such as patients and policy makers, may not have sufficient background for deciding which levels of reliability are acceptable. It is shown that the reliability is related to various probabilities that may be easier to understand, for example, the proportion of organizations that will be classed significantly above (or below) the mean and the probability that an organization is classed correctly given that it is classed significantly above (or below) the mean. One can view these probabilities as the amount of information of the classification and the correctness of the classification. These probabilities have an inverse relationship: given a reliability, one can 'buy' correctness at the cost of informativeness and conversely. This article discusses how this can be used to make judgments about the required level of reliabilities. PMID:23703932

  16. Joint probabilities and quantum cognition

    E-print Network

    J. Acacio de Barros

    2012-07-03

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

  17. Joint probabilities and quantum cognition

    NASA Astrophysics Data System (ADS)

    de Barros, J. Acacio

    2012-12-01

    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.

  18. Evaluation of microbial release probabilities

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Work undertaken to improve the estimation of the probability of release of microorganisms from unmanned Martian landing spacecraft is summarized. An analytical model is described for the development of numerical values for release parameters and release mechanisms applicable to flight missions are defined. Laboratory test data are used to evolve parameter values for use by flight projects in estimating numerical values for release probabilities. The analysis treats microbial burden located on spacecraft surfaces, between mated surfaces, and encapsulated within materials.

  19. Probability Bracket Notation: Probability Space, Conditional Expectation and Introductory Martingales

    E-print Network

    Xing M. Wang

    2009-10-15

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

  20. On classical finite probability theory as a quantum probability calculus

    E-print Network

    David Ellerman

    2015-02-03

    This paper shows how the classical finite probability theory (with equiprobable outcomes) can be reinterpreted and recast as the quantum probability calculus of a pedagogical or "toy" model of quantum mechanics over sets (QM/sets). There have been four previous attempts to develop a quantum-like model with the base field of $\\mathbb{C}$ replaced by $\\mathbb{Z}_{2}$, but they are all forced into a merely "modal" interpretation by requiring the brackets to take values in $\\mathbb{Z}_{2}$ (1 = possible, 0 = impossible). But the usual QM brackets give the "overlap" between states {\\psi} and {\\phi}, so for subsets S,T of U, the natural definition is $=|S{\\cap}T|$. This allows QM/sets to be developed with a full probability calculus that turns out to be the perfectly classical Laplace-Boole finite probability theory. The point is not to clarify finite probability theory but to elucidate quantum mechanics itself by seeing some of its quantum features (e.g., two-slit experiment) in a classical setting.

  1. Prolapse of the posterior leaflet: resect or respect

    PubMed Central

    Hohenberger, Wolfgang; Lakew, Fitsum; Diegeler, Anno

    2015-01-01

    Prolapse of the posterior leaflet (PPL) is the most frequent dysfunction of the mitral valve in the western world. Quadrangular resection, first proposed by Alain Carpentier, has progressed to become the gold standard modality to repair posterior leaflet prolapse. Although this “resection technique” is safe, reproducible, and offers favorable long term results, it presents major drawbacks. Firstly, it leads to a reduced surface of coaptation, the ultimate goal of mitral valve repair; secondly, it does not respect the anatomy of the mitral valve; thirdly, it leads to a deformation of the base of the ventricle; and finally, degenerative disease of the mitral valve is a spectrum of lesions depending on the amount of excess tissue, and hence, a one technique-fits-all strategy cannot meet the absolute necessity to repair all mitral valve patients with PPL. Therefore, new approaches which have been proposed place greater emphasis on respecting, rather than only resecting, the leaflet tissue in order to avoid the drawbacks of the “resection” approach. The use of artificial chordae to correct the leaflet prolapse restores the normal anatomy and physiology of the mitral valve, thus producing an optimal surface of coaptation. However, this approach is limited by anatomical variances. As a community, we should expand our vision and define a clear and helpful strategy for PPL: to obtain a high, smooth and regular surface of coaptation located in the inflow of the left ventricle. To achieve this goal, it is necessary to have a high level of respect for the leaflet tissue in order to obtain the best surface of coaptation. Nonetheless, a limited resection may be needed to remodel the posterior leaflet, so that it will be smooth and regular. PMID:26309830

  2. Management of presacral tumors: Our experience with posterior approach

    PubMed Central

    Saxena, Dhananjay; Pandey, Abhinav; Bugalia, Rajendra Prasad; Kumar, Mahendra; Kadam, Raju; Agarwal, Vipul; Goyal, Amit; Kankaria, Jeevan; Jenaw, Raj Kamal

    2015-01-01

    Introduction Presacral tumors are a rare variety of space occupying lesions arising in the presacral space. Most of the tumors are congenital in origin. Due to obscure anatomic location, difficult surgical approach and etiological heterogeneity, tumors arising here pose a diagnostic and therapeutic challenge. We report our experience of 10 cases of presacral tumors with posterior approach being used in 6. Materials and methods A retrospective analysis was conducted on 10 cases of presacral tumors managed at our hospital during a period of 14 months (May 2013–July 2014). 9 cases were operated while one had advanced disease and was referred for palliative care. Complete en bloc excision of the mass was possible in 8 cases. Finally, presenting complaints, clinical diagnosis, surgical procedure and histopahological findings of the cases were studied. Results All of our patients were females in the age group of 18–50 (mean 28.4) years. The pathological findings included schwannoma, leiomyosarcoma, hemangiopericytoma, neurofibroma, paraganglioma and rest were developmental cysts. 6 cases were managed using the posterior approach and rest by anterior approach. There was no major complication or mortality in the follow up. Conclusion Complete surgical excision remains the mainstay of therapy. Surgical approach depends upon the location, size, local invasion and surgical expertise of the surgeon. Benign tumors have a good prognosis while the prognosis in malignant tumors remains guarded due to difficulty in obtaining safe resection margins. Posterior approach is an attractive option for low lying, benign tumors that is more direct, with better exposure and quicker recovery. PMID:25996775

  3. Coding of Reward Probability and Risk by Single Neurons in Animals

    PubMed Central

    Burke, Christopher J.; Tobler, Philippe N.

    2011-01-01

    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. PMID:22013410

  4. Posterior shoulder instability following anatomic total shoulder arthroplasty: A case report and review of management

    PubMed Central

    Galvin, Joseph W.; Eichinger, Josef K.; Boykin, Robert E.; Szöllösy, Gregor; Lafosse, Laurent

    2015-01-01

    We report a case of posterior shoulder instability following anatomic total shoulder arthroplasty (TSA). In addition, we present guidelines to aid in the management of posterior instability after TSA. A 50-year-old male underwent anatomic TSA for glenohumeral osteoarthritis. Postoperatively, the patient developed posterior instability secondary to glenoid retroversion. He did not improve despite conservative treatment. He underwent an arthroscopic posterior bone block procedure, 4-month after his index arthroplasty. At 14-month follow-up, the patient had regained near full motion and strength, and radiographs demonstrated osseous integration with no evidence of component loosening. Posterior instability following TSA is a relatively rare complication and challenging to manage. The posterior, arthroscopic iliac crest bone block grafting procedure represents a treatment option for posterior instability in the setting of a stable glenoid prosthesis following TSA.

  5. Joint probability distributions for projection probabilities of random orthonormal states

    E-print Network

    L. Alonso; T. Gorin

    2015-10-19

    A finite dimensional quantum system for which the quantum chaos conjecture applies has eigenstates, which show the same statistical properties than the column vectors of random orthogonal or unitary matrices. Here, we consider the different probabilities for obtaining a specific outcome in a projective measurement, provided the system is in one of its eigenstates. We then give analytic expressions for the joint probability density for these probabilities, with respect to the ensemble of random matrices. In the case of the unitary group, our results can be applied, also, to the phenomenon of universal conductance fluctuations, where the same mathematical quantities describe partial conductances in a two-terminal mesoscopic scattering problem with a finite number of modes in each terminal.

  6. Secondary closure of neodymium:YAG laser posterior capsulotomy.

    PubMed

    Oshika, T; Santou, S; Kato, S; Amano, S

    2001-10-01

    A 67-year-old man reported reduced vision after cataract surgery and neodymium:YAG (Nd:YAG) laser posterior capsulotomy. The diagnosis was complicated due to severe glistenings within the optic of an acrylic foldable intraocular lens (IOL), proliferation of lens epithelial remnants over the capsulotomy opening, and presumed vitreous opacity. Although IOL exchange surgery was considered, a second Nd:YAG laser intervention successfully removed the proliferated lens materials and restored the visual acuity. The glistenings were not the cause of the reduced vision. PMID:11687373

  7. Consolidation of Complex Events via Reinstatement in Posterior Cingulate Cortex

    PubMed Central

    Keidel, James L.; Ing, Leslie P.; Horner, Aidan J.

    2015-01-01

    It is well-established that active rehearsal increases the efficacy of memory consolidation. It is also known that complex events are interpreted with reference to prior knowledge. However, comparatively little attention has been given to the neural underpinnings of these effects. In healthy adults humans, we investigated the impact of effortful, active rehearsal on memory for events by showing people several short video clips and then asking them to recall these clips, either aloud (Experiment 1) or silently while in an MRI scanner (Experiment 2). In both experiments, actively rehearsed clips were remembered in far greater detail than unrehearsed clips when tested a week later. In Experiment 1, highly similar descriptions of events were produced across retrieval trials, suggesting a degree of semanticization of the memories had taken place. In Experiment 2, spatial patterns of BOLD signal in medial temporal and posterior midline regions were correlated when encoding and rehearsing the same video. Moreover, the strength of this correlation in the posterior cingulate predicted the amount of information subsequently recalled. This is likely to reflect a strengthening of the representation of the video's content. We argue that these representations combine both new episodic information and stored semantic knowledge (or “schemas”). We therefore suggest that posterior midline structures aid consolidation by reinstating and strengthening the associations between episodic details and more generic schematic information. This leads to the creation of coherent memory representations of lifelike, complex events that are resistant to forgetting, but somewhat inflexible and semantic-like in nature. SIGNIFICANCE STATEMENT Memories are strengthened via consolidation. We investigated memory for lifelike events using video clips and showed that rehearsing their content dramatically boosts memory consolidation. Using MRI scanning, we measured patterns of brain activity while watching the videos and showed that, in a network of brain regions, similar patterns of brain activity are reinstated when rehearsing the same videos. Within the posterior cingulate, the strength of reinstatement predicted how well the videos were remembered a week later. The findings extend our knowledge of the brain regions important for creating long-lasting memories for complex, lifelike events. PMID:26511235

  8. Amoebic cervicitis mimicking posterior wall fibroid: a rare presentation.

    PubMed

    Mukherjee, Soma; Nagarsenkar, Ajit; Chandra, Savita; Sahasrabhojanee, Mrinalini; Sawant, Dheeraj

    2014-08-01

    Amoebiasis of the uterine cervix is an extremely rare entity, and presentation as fibroid uterus has not been reported, to the best of our knowledge in our extensive search of the English literature. It can clinically simulate cervical malignancy by virtue of surface papillomatous and overall ulcerated and necrotic appearance. We present a case of amoebic infection of the cervix in a 45-year-old female which was suspected to be a posterior wall fibroid with degeneration until a histopathological examination of the surgical specimen revealed the presence of Entamoeba histolytica trophozoites. The patient recovered after surgery and antiamoebic therapy. PMID:22743593

  9. Neuralgic Amyotrophy Manifesting as Mimicking Posterior Interosseous Nerve Palsy

    PubMed Central

    Yang, Jin Seo; Kang, Suk Hyung; Choi, Eun Hi

    2015-01-01

    The upper trunk of the brachial plexus is the most common area affected by neuralgic amyotrophy (NA), and paresis of the shoulder girdle muscle is the most prevalent manifestation. Posterior interosseous nerve palsy is a rare presentation in patients with NA. It results in dropped finger on the affected side and may be misdiagnosed as entrapment syndrome or compressive neuropathy. We report an unusual case of NA manifested as PIN palsy and suggest that knowledge of clinical NA phenotypes is crucial for early diagnosis of peripheral nerve palsies. PMID:26713154

  10. Prodromal Posterior Cortical Atrophy: Clinical, Neuropsychological and Radiological Correlation

    PubMed Central

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

    2015-01-01

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

  11. Automatic detection of posterior subcapsular cataract opacity for cataract screening.

    PubMed

    Li, Huiqi; Lim, Joo Hwee; Liu, Jiang; Wong, Damon Wing Kee; Foo, Yongfeng; Sun, Ying; Wong, Tien Yin

    2010-01-01

    Cataract is the leading cause of blindness and posterior subcapsular cataract (PSC) leads to significant visual impairment. An automatic approach for detecting PSC opacity in retro-illumination images is investigated. The features employed include intensity, edge, size and spatial location. The system was tested using 441 images. The automatic detection was compared with the human expert. The sensitivity and specificity are 82.6% and 80% respectively. The preliminary research indicates it is feasible to apply automatic detection in the clinical screening of PSC in the future. PMID:21096260

  12. Considerations for ceramic inlays in posterior teeth: a review

    PubMed Central

    Hopp, Christa D; Land, Martin F

    2013-01-01

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

  13. Small cell neuroendocrine carcinoma of the posterior tongue.

    PubMed

    Gumusay, Ozge; Yilmaz, Guldal; Aydil, Utku; Ozet, Ahmet; Tufan, Gulnihal; Erdem, Ozlem; Kizil, Yusuf; Benekli, Mustafa

    2015-01-01

    In the head and neck mucosa, neuroendocrine carcinomas of the oral cavity is rare. Herein, we present the first report of a small cell neuroendocrine carcinoma in a 54-year-old man on the right lateral posterior tongue. It is important to remember that although neuroendocrine small cell carcinomas (SCCs) are most commonly seen in the lung, they rarely may arise in the extrapulmonary sites, including salivary glands, as well. As there is not any standard therapeutic regimen already existing, it is important to be aware of and to know how to deal with such rare cases. PMID:26458628

  14. Hereditary anterior megalophthalmos with posterior vitreoretinopathy: a surgical challenge.

    PubMed

    Rao, Aparna; Videkar, Chetan

    2014-01-01

    Anterior megalophthalmos is an inherited condition characterised by enlargement of the anterior segment with associated glaucoma and vitreoretinopathy. These associations make surgical management very challenging. A 12-year-old boy, diagnosed and operated elsewhere for congenital glaucoma in both eyes, presented with raised intraocular pressure. Investigations revealed enlarged corneal diameter, increased anterior chamber depth with thick, clear cornea and no Haab striae while fundus evaluation revealed posteriorly dislocated cataractous lens with total rhegmatogenous retinal detachment in both eyes. The surgical challenges in management are highlighted in this case where appropriate investigations can aid in the selection of appropriate surgeries with good visual outcome. PMID:24632899

  15. Current approach in the diagnosis and management of posterior uveitis

    PubMed Central

    Sudharshan, S; Ganesh, Sudha K; Biswas, Jyotrimay

    2010-01-01

    Posterior uveitic entities are varied entities that are infective or non-infective in etiology. They can affect the adjacent structures such as the retina, vitreous, optic nerve head and retinal blood vessels. Thorough clinical evaluation gives a clue to the diagnosis while ancillary investigations and laboratory tests assist in confirming the diagnosis. Newer evolving techniques in the investigations and management have increased the diagnostic yield. In case of diagnostic dilemma, intraocular fluid evaluation for polymerase chain testing for the genome and antibody testing against the causative agent provide greater diagnostic ability. PMID:20029144

  16. Neuropathology of a fatal case of posterior reversible encephalopathy syndrome.

    PubMed

    Kheir, John N; Lawlor, Michael W; Ahn, Edward S; Lehmann, Leslie; Riviello, James J; Silvera, V Michelle; McManus, Michael; Folkerth, Rebecca D

    2010-01-01

    The pathology of posterior reversible encephalopathy syndrome (PRES) is undefined, since it is rarely fatal and is biopsied in only exceptional circumstances. We describe rapidly progressive PRES following stem cell transplant for acute lymphoblastic leukemia. After development of altered mental status, this 8-year-old girl had T2 prolongation of the white matter in a posterior-dominant distribution, eventually developing cerebellar edema, hemorrhage, hydrocephalus, and herniation. Despite surgical and medical management, she died 36 hours later. At autopsy, the occipital and cerebellar white matter and focal occipital cortical gray matter showed a spectrum of microvascular changes, including dilated perivascular spaces containing proteinaceous exudates and macrophages, as well as fibrinoid necrosis and acute hemorrhage, in a distribution corresponding to the neuroimaging abnormalities and reminiscent of those seen in patients with acute hypertensive encephalopathy. Of note, similar microvascular changes were not seen in the kidney or other systemic sites. Thus, the findings indicate a brain-specific microvascular compromise as the substrate of PRES, at least in the rare instance of cases progressing to fatal outcome. PMID:20158377

  17. Improvements in interpretation of posterior capsular opacification (PCO) images

    NASA Astrophysics Data System (ADS)

    Paplinski, Andrew P.; Boyce, James F.; Barman, Sarah A.

    2000-06-01

    We present further improvements to the methods of interpretation of the Posterior Capsular Opacification (PCO) images. These retro-illumination images of the back surface of the implanted lens are used to monitor the state of patient's vision after cataract operation. A common post-surgical complication is opacification of the posterior eye capsule caused by the growth of epithelial cells across the back surface of the capsule. Interpretation of the PCO images is based on their segmentation into transparent image areas and opaque areas, which are affected by the growth of epithelial cells and can be characterized by the increase in the image local variance. This assumption is valid in majority of cases. However, for different materials used for the implanted lenses it sometimes happens that the epithelial cells grow in a way characterized by low variance. In such a case segmentation gives a relatively big error. We describe an application of an anisotropic diffusion equation in a non-linear pre-processing of PCO images. The algorithm preserves the high-variance areas of PCO images and performs a low-pass filtering of small low- variance features. The algorithm maintains a mean value of the variance and guarantees existence of a stable solution and improves segmentation of the PCO images.

  18. Recurrent Posterior Strokes in Inflammatory Bowel Disease Patients

    PubMed Central

    Hymel, Brett; Chavez-Keatts, Maria; Karlitz, Jordan J.; Martin-Schild, Sheryl

    2015-01-01

    Objective. To describe the stroke characteristics of patients with a history of inflammatory bowel disease (IBD). Background. A hypercoagulable state associated with IBD has been frequently implicated as a risk factor for ischemic stroke. Variable mechanisms and infrequent occurrence limit prospective clinical research on the association between IBD and stroke. Methods. We retrospectively reviewed consecutive patients with acute ischemic stroke presenting to our medical center from 7/2008 to 9/2013. Patients with a history of IBD were identified. Clinical variables were abstracted from our prospective stroke registry. Results. Over the period of five years we identified only three patients with a documented history of IBD. Each of these patients presented three times to our hospital with new strokes. Patients presented outside the window for intravenous tPA treatment on 8/9 admissions. Each one of our patients had posterior strokes on at least two separate occasions. Hypercoagulation panel showed elevated factor VIII with or without concomitant elevation of Von Willebrand factor (vWF) during almost every admission (8/9 admissions). Only one admission was associated with IBD flare. Conclusion. The association between IBD and posterior strokes is a novel finding. Factor VIII elevation may serve as a biomarker of a peristroke hypercoagulable state in patients with IBD. PMID:25784930

  19. Rehabilitative ultrasound imaging of the posterior paraspinal muscles.

    PubMed

    Stokes, Maria; Hides, Julie; Elliott, James; Kiesel, Kyle; Hodges, Paul

    2007-10-01

    Interest in rehabilitative ultrasound imaging (RUSI) of the posterior paraspinal muscles is growing, along with the body of literature to support integration of this technique into routine physical therapy practice. This clinical commentary reviews how RUSI can be used as an evaluative and treatment tool and proposes guidelines for its use for the posterior muscles of the lumbar and cervical regions. Both quantitative and qualitative applications are described, as well as measurement reliability and validity. Measurement of morphological characteristics of the muscles (morphometry) in healthy populations and people with spinal pathology are described. Preliminary normal reference data exist for measurements of cross-sectional area (CSA), linear dimensions (muscle depth/thickness and width), and shape ratios. Compared to individuals without low back pain, changes in muscles' size at rest and during the contracted state have been observed using RUSI in people with spinal pathology. Visual observation of the image during contraction indicates that RUSI may be a valuable biofeedback tool. Further investigation of many of these observations is required using controlled studies to provide conclusive evidence that RUSI enhances clinical practice. PMID:17970405

  20. Finite Element Modeling of the Posterior Eye in Microgravity

    NASA Technical Reports Server (NTRS)

    Feola, Andrew; Raykin, Julia; Mulugeta, Lealem; Gleason, Rudolph; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian; Ethier, C. Ross

    2015-01-01

    Microgravity experienced during spaceflight affects astronauts in various ways, including weakened muscles and loss of bone density. Recently, visual impairment and intracranial pressure (VIIP) syndrome has become a major concern for space missions lasting longer than 30 days. Astronauts suffering from VIIP syndrome have changes in ocular anatomical and visual impairment that persist after returning to earth. It is hypothesized that a cephalad fluid shift in microgravity may increase the intracranial pressure (ICP), which leads to an altered biomechanical environment of the posterior globe and optic nerve sheath (ONS).Currently, there is a lack of knowledge of how elevated ICP may lead to vision impairment and connective tissue changes in VIIP. Our goal was to develop a finite element model to simulate the acute effects of elevated ICP on the posterior eye and optic nerve sheath. We used a finite element (FE) analysis approach to understand the response of the lamina cribrosa and optic nerve to the elevations in ICP thought to occur in microgravity and to identify which tissue components have the greatest impact on strain experienced by optic nerve head tissues.

  1. Surgery for severe thoracolumbar fracture dislocation via a posterior approach.

    PubMed

    Feng, Zhang; Xiaoqing, Chen; Xiangdong, Chen; Junjie, Guan; Xingjie, Jiang; Yu, Yao; Ming, Li; Jian, Zhao; Yong, Cao

    2015-12-01

    Between June 2008 and June 2013, our department treated 16 severe thoracolumbar fracture dislocations (13 male and three female patients; mean age 33.6years) with a pedicle screw system via an entirely posterior approach. We followed all patients for 18-69months (mean 35months). The mean operation time was 170minutes (range: 120-280), and mean blood loss was 700ml (range: 450-1300). The percentage displacement (mean±standard deviation) improved from a preoperative value of 72±20% to 10±6% postoperatively, and the deformity angle (mean±standard deviation) improved from 29.2±15.0° to 12.6±6.7°. Of the six patients with American Spinal Injury Association Grade A, one improved to Grade B, one to Grade C and four had little improvement. Of the five patients with Grade B, three improved to Grade C and two to Grade D. Of the four Grade C patients, two improved to Grade D, and the other two to Grade E. One Grade D patient improved to Grade E. No loosening or breakage of the internal implants occurred in the follow-up period. Therefore, we conclude that although it is difficult, the posterior approach alone is safe and biomechanically reliable for treating severe thoracolumbar fracture dislocations. The maintenance of deformity correction and stable local mechanical reconstruction in the follow-up period support this single approach strategy. PMID:26321305

  2. Management of disorders of the posterior pelvic floor.

    PubMed Central

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

    2005-01-01

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

  3. The right posterior paravermis and the control of language interference.

    PubMed

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

    2011-07-20

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

  4. Distinct value signals in anterior and posterior ventromedial prefrontal cortex.

    PubMed

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

    2010-02-17

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

  5. Intraoperative monitoring during selective posterior rhizotomy: technique and patient outcome.

    PubMed

    Staudt, L A; Nuwer, M R; Peacock, W J

    1995-12-01

    We evaluated intraoperative electromyographic (EMG) results among 110 pediatric patients with spastic cerebral palsy who underwent selective posterior rhizotomy. We analyzed surgical outcomes for 60 of these patients who returned for follow-up assessment between 4 and 17 months postoperatively. Reduction in muscle tone (resistance to passive movement), increased range of motion and improvements in functional skills were seen at follow-up. To control for possible changes due to development, participation in therapy, or instability of measurements, 30 rhizotomy patients were evaluated twice during a baseline period of several months prior to surgery. No significant changes were found between these two measurement sessions during the baseline control period suggesting that the rhizotomy surgery itself caused the postoperative improvements. These intraoperative EMG monitoring techniques have been adopted at many other centers but variations in specific methods and EMG criteria have developed subsequently among major hospitals where selective posterior rhizotomy is performed. These variations in neurophysiologic methods and recent controversy about the usefulness of such intraoperative EMG monitoring created a need for us to publish our standard EMG selection technique. We describe here, in detail, methods for nerve rootlet testing and selection. PMID:8536579

  6. A Generalized, Likelihood-Free Method for Posterior Estimation

    PubMed Central

    Turner, Brandon M.; Sederberg, Per B.

    2014-01-01

    Recent advancements in Bayesian modeling have allowed for likelihood-free posterior estimation. Such estimation techniques are crucial to the understanding of simulation-based models, whose likelihood functions may be difficult or even impossible to derive. However, current approaches are limited by their dependence on sufficient statistics and/or tolerance thresholds. In this article, we provide a new approach that requires no summary statistics, error terms, or thresholds, and is generalizable to all models in psychology that can be simulated. We use our algorithm to fit a variety of cognitive models with known likelihood functions to ensure the accuracy of our approach. We then apply our method to two real-world examples to illustrate the types of complex problems our method solves. In the first example, we fit an error-correcting criterion model of signal detection, whose criterion dynamically adjusts after every trial. We then fit two models of choice response time to experimental data: the Linear Ballistic Accumulator model, which has a known likelihood, and the Leaky Competing Accumulator model whose likelihood is intractable. The estimated posterior distributions of the two models allow for direct parameter interpretation and model comparison by means of conventional Bayesian statistics – a feat that was not previously possible. PMID:24258272

  7. Running Head: Understandings of Probability Teachers' Understandings of Probability

    E-print Network

    Thompson, Patrick W.

    an enormous impact on scientific and cultural developments in society. In the 18th century, it was applied values and assumptions about matters as diverse as legal fairness to human intelligence. Given knowledge concerning which of a set of alternatives is true, into a uniform probability distribution over

  8. Dynamical origin of quantum probabilities

    NASA Astrophysics Data System (ADS)

    Valentini, Antony; Westman, Hans

    2005-01-01

    We study the origin of the Born probability rule ? = |?|2 in the de Broglie-Bohm pilot-wave formulation of quantum theory. It is argued that quantum probabilities arise dynamically, and have a status similar to thermal probabilities in ordinary statistical mechanics. This is illustrated by numerical simulations for a two-dimensional system. We show that a simple initial ensemble, with a non-standard distribution ? ? |?|2 of particle positions, evolves towards the quantum distribution to high accuracy. The relaxation process ? ? |?|2 is quantified in terms of a coarse-grained H-function (equal to minus the relative entropy of ? with respect to |?|2), which is found to decrease approximately exponentially over time, with a time constant that accords with a simple theoretical estimate.

  9. Fusion Probability in Dinuclear System

    E-print Network

    Hong, Juhee

    2015-01-01

    Fusion can be described by the time evolution of a dinuclear system with two degrees of freedom, the relative motion and transfer of nucleons. In the presence of the coupling between two collective modes, we solve the Fokker-Planck equation in a locally harmonic approximation. The potential of a dinuclear system has the quasifission barrier and the inner fusion barrier, and the escape rates can be calculated by the Kramers' model. To estimate the fusion probability, we calculate the quasifission rate and the fusion rate. We investigate the coupling effects on the fusion probability and the cross section of evaporation residue.

  10. Interference of probabilities in dynamics

    SciTech Connect

    Zak, Michail

    2014-08-15

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

  11. Fusion Probability in Dinuclear System

    E-print Network

    Juhee Hong

    2015-03-26

    Fusion can be described by the time evolution of a dinuclear system with two degrees of freedom, the relative motion and transfer of nucleons. In the presence of the coupling between two collective modes, we solve the Fokker-Planck equation in a locally harmonic approximation. The potential of a dinuclear system has the quasifission barrier and the inner fusion barrier, and the escape rates can be calculated by the Kramers' model. To estimate the fusion probability, we calculate the quasifission rate and the fusion rate. We investigate the coupling effects on the fusion probability and the cross section of evaporation residue.

  12. Probability, Interpretations of1 1. INTRODUCTION

    E-print Network

    Fitelson, Branden

    of religion. Thus, problems in the foundations of probability bear at least indirectly, and sometimes directly the most important such foundational problem. 2. KOLMOGOROV'S PROBABILITY CALCULUS Probability theory1 Probability, Interpretations of1 1. INTRODUCTION 'Interpreting probability' is a commonly used

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

    PubMed

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

    2014-08-01

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

  14. Phonotactic Probability Influences Speech Production

    ERIC Educational Resources Information Center

    Goldrick, Matthew; Larson, Meredith

    2008-01-01

    Speakers are faster and more accurate at processing certain sound sequences within their language. Does this reflect the fact that these sequences are frequent or that they are phonetically less complex (e.g., easier to articulate)? It has been difficult to contrast these two factors given their high correlation in natural languages. In this…

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

    PubMed Central

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

    2014-01-01

    Objective: To perform dual-bundle reconstruction of posterior cruciate ligament using full arthroscopic tibial inlay technology with self-designed tibia tunnel drilling system and to compare the effect of arthroscopic tibial inlay versus traditional technique for posterior cruciate ligament reconstruction. Material and methods: 32 patients were randomly divided into experiment group (improved tibial inlay, n = 17) and control group (traditional tibial inlay, n = 15). Self-designed tibia tunnel drill system was used to produce intraoperative deep-limited bone tunnel. During follow-up, the location of the bone block and the healing situation were checked by knee X-ray and spiral CT scan. Blood loss, operation time and nerve vascular injuries were evaluated. Results: Mean intraoperative blood loss was 123.53 ± 74.05 ml in the improved tibial inlay group compared with 332 ± 114.26 ml in the traditional tibial inlay group (t = 6.12, P < 0.05). Mean operation time was 235.27 ± 58.88 min in the improved tibial inlay group compared with 346.37 ± 59.67 min in the traditional tibial inlay group (t = 5.19, P < 0.05). Posterior drawer test were negative in 15 cases, slight positive in 2 with improved tibial inlay technique compared with 14 negative cases and 2 positive cases of traditional tibial Inlay technique. The X-ray and spiral CT scan showed the location of the bone block were perfect and healed well with the patent who received improved tibial inlay technology after 12 weeks postoperatively. Conclusion: Accurate depth-limited bone tunnel can be produced by the tibia tunnel drill system with minor trauma, less bleeding and reducing of nerves or vessels and the recent clinical effects of PCL reconstruction were pretty good. PMID:25419349

  16. GPS: Geometry, Probability, and Statistics

    ERIC Educational Resources Information Center

    Field, Mike

    2012-01-01

    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…

  17. Probable Supernova discovered by PSST

    NASA Astrophysics Data System (ADS)

    Wright, D.; Smith, K. W.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2015-11-01

    A bright transient, which is a probable supernova, has been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  18. Probability Simulation in Middle School.

    ERIC Educational Resources Information Center

    Lappan, Glenda; Winter, M. J.

    1980-01-01

    Two simulations designed to teach probability to middle-school age pupils are presented. The first simulates the one-on-one foul shot simulation in basketball; the second deals with collecting a set of six cereal box prizes by buying boxes containing one toy each. (MP)

  19. Comments on quantum probability theory.

    PubMed

    Sloman, Steven

    2014-01-01

    Quantum probability theory (QP) is the best formal representation available of the most common form of judgment involving attribute comparison (inside judgment). People are capable, however, of judgments that involve proportions over sets of instances (outside judgment). Here, the theory does not do so well. I discuss the theory both in terms of descriptive adequacy and normative appropriateness. PMID:24482328

  20. Probability (Math/Stat 511)

    E-print Network

    Sharpley, Robert

    Probability (Math/Stat 511) Test 3 ­ April 4, 2001 Directions: Answer all questions in the space call that arrives after 9 a.m. a.) What is the p.d.f. of X and the corresponding required parameters? b

  1. Stereotaxic atlas of the goat brain for an accurate approach to the hypothalamic nuclei.

    PubMed

    Sunagawa, Katsunori; Nagamine, Itsuki; Fujino, Tetsuya; Nakatsu, Yoshifumi; Hikosaka, Kazuo

    2015-06-01

    While the external acoustic meatus of mice, rats and cats are at right angles to the side of the head, they are angled forward in ruminants. Because of this, the coordinates of stereotaxic atlases created using the same methods as for small animals were not suitable for practical use and made it very difficult to place electrodes in hypothalamic nuclei. The aim of this study was to produce a highly accurate stereotaxic atlas for goats that enables precise placement of electrodes in the hypothalamic nuclei. A method of fixing the head in place so as to maintain the basis cranii interna in a horizontal position was established allowing right angled three dimensional axes to be superimposed in the brains of Japanese Saanen goats. This research attempted to establish a new landmark alternative to the external acoustic meatus. The new landmark is the extremitas posterior clivus presphenoidale (EPCP) at the base of cranial bone. This landmark can easily be visualized through lateral radiography. This enabled the AP (anterior-posterior) and H (height) coordinates of the position to be fixed at 30 and 5, respectively. The A30 and H5 coordinates of the serial frontal, sagittal, and horizontal stereotaxic atlases in the present experiment were set to coincide with the position of the EPCP. In order to clarify whether the deviation of the stereotaxic brain coordinates due to inconsistent immobilization the goat's head was eliminated, the AP and H coordinates of the extremitas anterior fossa hypophysialis and the extremitas posterior fossa hypophysialis were measured using the corrected axes. In the three dimensional stereotaxic atlas created using the new landmark, it became possible to approach the hypothalamic nuclei of goats accurately. This method significantly differentiates the stereotaxic atlas from its predecessors. PMID:25817539

  2. Topographically Organized Projection to Posterior Insular Cortex from the Posterior Portion of the Ventral Medial Nucleus (VMpo) in the Long-tailed Macaque Monkey

    PubMed Central

    Craig, A.D. (Bud)

    2014-01-01

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

  3. Modeling Prostate Cancer Detection Probability, with Applications

    E-print Network

    Serfling, Robert

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

  4. Using Playing Cards to Differentiate Probability Interpretations

    ERIC Educational Resources Information Center

    López Puga, Jorge

    2014-01-01

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

  5. A Formulation for Minimax Probability Machine Regression

    E-print Network

    Grudic, Greg

    problem as one of maximizing the mini- mum probability, symbolized by , that future predicted outputs trivial regression problems. As with the minimax probability machine classification (MPMC) frameworkA Formulation for Minimax Probability Machine Regression Thomas Strohmann Department of Computer

  6. Concurrent Periostalgia and Chronic Proximal Deep Posterior Compartment Syndrome in a Collegiate Track and Field Athlete: A Case Report

    PubMed Central

    Heinrichs, Kristinn I.; Lachowicz, Wendy M.; Detmer, Don E.

    2000-01-01

    Objective: Exercise-induced leg pain may be triggered by abnormally high compartment pressure. In addition to the more widely publicized anterior compartment syndrome, the deep posterior compartment syndrome can just as frequently occur, resulting in severe pain and disability due to muscle and nerve ischemia. Background: Obtaining a thorough history and compartmental pressure measurements are the usual components in the accurate diagnosis of compartment syndromes. While few other disorders mimic compartment syndromes, differential diagnoses must be considered. Surgical management of deep compartment syndrome, consisting of fasciotomy or fasciectomy, or both, is successful for most patients. Differential Diagnosis: Tibial stress fracture or microfracture, tibial periostitis, tibial periostalgia, distal deep posterior chronic compartment syndrome, proximal deep chronic compartment syndrome, superficial lateral compartment syndrome, deep venous thrombosis, popliteal artery entrapment, or chronic compartment syndrome. Uniqueness: Chronic deep compartment syndrome is one of the most common causes of exercise-induced leg pain in aerobic athletes. Therefore, the athletic trainer must be able to recognize the condition. Signs, symptoms, diagnosis, and surgical management of chronic deep compartment syndrome, chronic periostalgia, and superficial lateral compartment syndrame in a 21-year-old Division IA track and field athlete are presented. Conclusions: With the correct diagnosis, persistent and methodical reevaluation, and appropriate management, the athlete can expect a successful treatment outcome. PMID:16558661

  7. A comparative study of retention of complete denture base with different types of posterior palatal seals – an in vivo study

    PubMed Central

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

    2014-01-01

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

  8. On the probability distributions of ellipticity

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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.

  9. Transient contribution of left posterior parietal cortex to cognitive restructuring.

    PubMed

    Sutoh, Chihiro; Matsuzawa, Daisuke; Hirano, Yoshiyuki; Yamada, Makiko; Nagaoka, Sawako; Chakraborty, Sudesna; Ishii, Daisuke; Matsuda, Shingo; Tomizawa, Haruna; Ito, Hiroshi; Tsuji, Hiroshi; Obata, Takayuki; Shimizu, Eiji

    2015-01-01

    Cognitive restructuring is a fundamental method within cognitive behavioural therapy of changing dysfunctional beliefs into flexible beliefs and learning to react appropriately to the reality of an anxiety-causing situation. To clarify the neural mechanisms of cognitive restructuring, we designed a unique task that replicated psychotherapy during a brain scan. The brain activities of healthy male participants were analysed using functional magnetic resonance imaging. During the brain scan, participants underwent Socratic questioning aimed at cognitive restructuring regarding the necessity of handwashing after using the restroom. The behavioural result indicated that the Socratic questioning effectively decreased the participants' degree of belief (DOB) that they must wash their hands. Alterations in the DOB showed a positive correlation with activity in the left posterior parietal cortex (PPC) while the subject thought about and rated own belief. The involvement of the left PPC not only in planning and decision-making but also in conceptualization may play a pivotal role in cognitive restructuring. PMID:25775998

  10. Changes in artistic style after minor posterior stroke

    PubMed Central

    Annoni, J; Devuyst, G; Carota, A; Bruggimann, L; Bogousslavsky, J

    2005-01-01

    Background: Two professional painters experienced significant changes in their art as the main consequence of minor stroke located in the left occipital lobe or thalamus. Methods: The features of this artistic conversion were analysed on the basis of extensive neurological, neuropsychological, and psychiatric evaluations. Results: Both painters, initially unaware of the artistic changes, exhibited mild signs of executive dysfunction, but no general cognitive decline. The first painter, who showed mild visual-perceptive difficulties (dyschromatopsia and scotoma in his right upper visual field after left occipital stroke), together with increased anxiety and difficulty in emotional control, switched to a more stylised and symbolic art. The second painter, who also presented features of emotionalism related to his left latero-thalamic stroke, switched from an impressionist style to a more joyous and geometric, but more simplistic, abstract art. Conclusions: These findings show that mild cognitive and affective modifications due to focal posterior brain lesions can have significant repercussions on artistic expression. PMID:15897501

  11. The posterior chamber phakic refractive lens (PRL): a review

    PubMed Central

    Pérez-Cambrodí, R J; Piñero, D P; Ferrer-Blasco, T; Cerviño, A; Brautaset, R

    2013-01-01

    Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient's accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on the latter is very low, and some concerns still remain about its long-term safety. The present article reviews the published literature on the outcomes after PRL implantation in order to provide a general overview and evaluate its real potential as a surgical refractive option. PMID:23222559

  12. Observations on persistently dilated ureter after posterior urethral valve ablation.

    PubMed

    Glassberg, K I; Schneider, M; Haller, J O; Moel, D; Waterhouse, K

    1982-07-01

    The persistent ureteral dilatation frequently seen months or even years after posterior urethral valve ablation, continues to present a dilemma to the urologist. We have classified these dilated ureters into 3 types: (I) unobstructed with either an empty or filling bladder, (II) unobstructed with an empty bladder but obstructed with a filling bladder, and (III) obstructed with either an empty or filling bladder. The majority of ureters with persistent dilatation were found to be of the type II variety where appropriate treatment is not obvious. Classic ureteral tailoring and reimplantation offers little advantage since in such cases a narrower ureter is passed through a new hiatus in an otherwise unchanged bladder. When high renal pelvic pressures are found only with bladder filling, then consideration must be given to not only reconstructing the ureter but also to affecting the dynamics of the bladder and the large urinary output characteristically found in these patients. PMID:7112792

  13. Evidence against pain specificity in the dorsal posterior insula

    PubMed Central

    Davis, Karen D.; Bushnell, M. Catherine; Iannetti, Gian Domenico; St. Lawrence, Keith; Coghill, Robert

    2015-01-01

    The search for a “pain centre” in the brain has long eluded neuroscientists.  Although many regions of the brain have been shown to respond to painful stimuli, all of these regions also respond to other types of salient stimuli. In a recent paper, Segerdahl et al. (Nature Neuroscience, 2015)  claims that the dorsal posterior insula (dpIns) is a pain-specific region based on the observation that the magnitude of regional cerebral blood flow (rCBF) fluctuations in the dpIns correlated with the magnitude of evoked pain.  However, such a conclusion is, simply, not justified by the experimental evidence provided.  Here we discuss three major factors that seriously question this claim. PMID:26401267

  14. Case of posterior reversible encephalopathy syndrome due to azathioprine.

    PubMed

    Ogawa, Ryo; Oikawa, Takanori; Shijo, Tomomi; Kanno, Shigenori; Shibuya, Satoshi; Mochizuki, Hiroshi

    2015-12-23

    This report describes a 15-year-old woman presenting posterior reversible encephalopathy syndrome (PRES) due to azathioprine. She was under treatment for ulcerative colitis. She was prescribed azathioprine seven days before admission. Four days after, she complained of headache. Then, she disturbed consciousness and showed generalized convulsive seizure on the day of admission. Magnetic resonance imaging (MRI) revealed vasogenic edema in both hemispheres. She was discontinued azathioprine and treated by anticonvulsant. Her symptoms were recovered and the MRI findings were disappeared. We diagnosed as PRES due to azathioprine because of clinical course and MRI findings. Only one case of PRES due to azathioprine is reported previously. Our case is the first report that showed the changes and improvement of MRI findings along the clinical course. PMID:26511023

  15. Reversible Posterior Leukoencephalopathy Syndrome Due to Carboplatin and Paclitaxel Therapy

    PubMed Central

    Kandemir, Melek; Küçükkaya, Belgin; Tepe, Muzaffer Sava?; Yalç?ner, Zehra Betül; Salepçi, Nedret Taflan

    2015-01-01

    Background: Reversible posterior leukoencephalopathy syndrome (RPLS) is a clinicoradiologic syndrome characterized by headache, decreased alertness, seizures, visual abnormalities, and white matter changes indicative of cerebral edema. Although the pathogenesis remains poorly understood, several etiological causes have been described. RPLS is a common complication of chemotherapeutics because of its toxic effect on the central nervous system. This syndrome is frequently associated with seizures but rarely seen with status epilepticus and periodic lateralized epileptiform discharges (PLEDs). Case Report: We present a case with metastatic lung cancer that developed RPLS after carboplatin and paclitaxel therapy. Our case was admitted to the hospital with status epilepticus and her electroencephalography showed PLEDs. Conclusion: It is important to closely monitor blood pressure and electrolyte levels in patients who take chemotherapeutic agents, especially when there is no previous history of hypertension. It should be kept in mind that RPLS is a causative factor of status epilepticus and PLEDs.

  16. Electromechanical flowmeter accurately monitors fluid flow

    NASA Technical Reports Server (NTRS)

    Grant, D. J.

    1965-01-01

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

  17. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...the measurement of limitation of motion is indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be accurately measured and reported. [41 FR 11294, Mar. 18,...

  18. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...the measurement of limitation of motion is indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be accurately measured and reported. [41 FR 11294, Mar. 18,...

  19. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...the measurement of limitation of motion is indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be accurately measured and reported. [41 FR 11294, Mar. 18,...

  20. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...the measurement of limitation of motion is indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be accurately measured and reported. [41 FR 11294, Mar. 18,...

  1. Accurate capacitive metrology for atomic force microscopy

    E-print Network

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

    2005-01-01

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

  2. Extreme lateral interbody fusion with posterior instrumentation for spondylodiscitis.

    PubMed

    Blizzard, Daniel J; Hills, Christopher P; Isaacs, Robert E; Brown, Christopher R

    2015-11-01

    The purpose of this study was to evaluate our initial experience utilizing extreme lateral interbody fusion (XLIF; NuVasive, San Diego, CA, USA) with percutaneous posterior instrumentation to treat 11 spondylodiscitis patients between January 2011 and February 2014. Although medical management is the first line treatment for spondylodiscitis, many patients fail antibiotic therapy and bracing, or present with instability, neurologic deficits, or sepsis, requiring operative debridement and stabilization. High rates of fusion and infection clearance have been reported with anterior lumbar interbody fusion (ALIF), but this approach requires a morbid exposure, associated with non-trivial rates of vascular and peritoneal complications. XLIF is an increasingly popular interbody fusion technique which utilizes a fast and minimally invasive approach, sparing the anterior longitudinal ligament, and allowing sufficient visualization of the intervertebral discs and bodies to debride and place a large, lordotic cage. The outcome measures for this study included lumbar lordosis, sagittal balance, subsidence, fusion, pain, neurological deficit, and microbiology/laboratory evidence of infection. The mean follow-up time was 9.3months. All patients had improvements in pain and neurological symptoms. The mean lordosis change was 11.0°, from 23.1° preoperatively to 34.0° postoperatively. Fusion was confirmed with CT scans in five of six patients. At the last follow-up, all patients had normalization of inflammatory markers, no symptoms of infection, and none required repeat surgical treatment for spondylodiscitis. XLIF with percutaneous posterior instrumentation is a minimally invasive technique with reduced morbidity for lumbar spine fusion which affords adequate exposure to the vertebral bodies and discs to aggressively debride necrotic and infected tissue. This study suggests that XLIF may be a safe and effective alternative to ALIF for the treatment of spondylodiscitis. PMID:26138052

  3. Superior Labrum Anterior Posterior Lesions and Associated Injuries

    PubMed Central

    Beyzadeoglu, Tahsin; Circi, Esra

    2015-01-01

    Background: Superior labrum anterior posterior (SLAP) lesions often cause shoulder pain, dysfunction, and instability. Professional athletes require a high level of shoulder function for competition and overhead activities. Purpose: To evaluate elite athletes who had arthroscopic surgery for common shoulder pathologies and SLAP lesions with a follow-up of more than 3 years. The associated intra-articular pathologies and return to play were documented. Study Design: Case series; Level of evidence, 4. Methods: Thirty-five shoulders in 34 elite athletes (4 women and 30 men; mean age, 25 years [range, 18-32 years]) had arthroscopic repair of SLAP lesions and accompanying Bankart or rotator cuff tears between January 2008 and November 2011. The documentation included patient symptoms, physical examination, radiological analysis with radiographs, and magnetic resonance imaging. Shoulder function was evaluated preoperatively and at follow-up using American Shoulder and Elbow Surgeons (ASES) and Kerlan Jobe Orthopaedic Clinic (KJOC) scores. The mean follow-up was 52 months. Results: Isolated SLAP lesions were seen in 17.1% of patients, SLAP lesions and partial cuff tear occurred in 25.7%, associated Bankart lesions in 37.1%, full-thickness rotator cuff tears in 8.6%, Bankart and posterior labrum lesions in 8.6%, and Bankart and full-thickness rotator cuff tears in 2.9%. Return to play was a mean 6.4 ± 1.5 months. The mean postoperative ASES and KJOC scores were 89.6 ± 4.6 and 80.9 ± 6.8, respectively, compared with preoperative scores of 64.0 ± 7.2 and 50.5 ± 10.3 (t test, P < .01). Conclusion: The majority (88.2%) of professional athletes returned to their preinjury levels. SLAP lesions may frequently occur with Bankart lesions and rotator cuff tears. A high rate of return to sport at the same level of athletic performance can be achieved by anatomic repair and effective rehabilitation.

  4. Cytology and Functionally Correlated Circuits of Human Posterior Cingulate Areas

    PubMed Central

    Vogt, Brent A.; Vogt, Leslie; Laureys, Steven

    2008-01-01

    Human posterior cingulate cortex (PCC) and retrosplenial cortex (RSC) form the posterior cingulate gyrus, however, monkey connection and human imaging studies suggest that PCC area 23 is not uniform and atlases mislocate RSC. We histologically assessed these regions in 6 postmortem cases, plotted a flat map, and characterized differences in dorsal (d) and ventral (v) area 23. Subsequently, functional connectivity of histologically guided regions of interest (ROI) were assessed in 163 [18F]fluorodeoxyglucose human cases with PET. Compared to area d23, area v23 had a higher density and larger pyramids in layers II, IIIc, and Vb and more intermediate neurofilament-expressing neurons in layer Va. Coregisrtration of each case to standard coordinates showed that the ventral branch of the splenial sulci coincided with the border between d/v PCC at ?5.4±0.17 cm from the vertical plane and +1.97±0.08 cm from the bi-commissural line. Correlation analysis of glucose metabolism using histologically guided ROIs suggested important circuit differences including dorsal and ventral visual stream inputs, interactions between the vPCC and subgenual cingulate cortex, and preferential relations between dPCC and the cingulate motor region. The RSC, in contrast, had restricted correlated activity with pericallosal cortex and thalamus. Visual information may be processed with an orbitofrontal link for synthesis of signals to drive premotor activity through dPCC. Review of the literature in terms of a PCC duality suggests that interactions of dPCC, including area 23d, orients the body in space via the cingulate motor areas, while vPCC interacts with subgenual cortex to process self-relevant emotional and non-emotional information and objects and self reflection. PMID:16140550

  5. Bevacizumab for the treatment of a complicated posterior melanocytoma

    PubMed Central

    Urrets-Zavalia, Julio A; Crim, Nicolas; Esposito, Evangelina; Correa, Leandro; Gonzalez-Castellanos, M Eugenia; Martinez, Dana

    2015-01-01

    Purpose To present a case of a complicated posterior melanocytoma that was successfully treated with intravitreal bevacizumab. Case report A 50-year-old Caucasian man was referred with sudden-onset metamorphopsia and decreased vision in his right eye over the course of the last 2 months. His best-corrected visual acuity was 20/80 and poorer than Jaeger 14 in the right eye, and 20/20 and Jaeger 1 in his left eye. In the right fundus, there was a melanocytic lesion occupying the inferotemporal quadrant of the optic disk, extending to the adjacent choroid inferiorly; optic nerve edema, superotemporal retinal vein dilatation, and subretinal fluid under the macula and nasal half of the posterior pole were observed, and a subretinal choroidal neovascularization complex was observed adjacent to the superotemporal margin of the optic disk, confirmed by fluorescein angiography, surrounded by a dense subretinal hemorrhage. Optical coherence tomography showed retinal edema and detachment of neurosensory retina. The patient was treated with three consecutive doses on a monthly basis of intravitreal 1.25 mg/0.05 mL bevacizumab. Visual acuity recovered rapidly, and at 4 months after treatment, it was 20/20 and Jaeger 1, with complete resolution of macular edema and subretinal fluid and hemorrhage. After 3 years of follow-up, best-corrected visual acuity remained stable, macular area was normal, and there was no evident optic nerve edema, retinal vein caliber and aspect were normal, and there was no significant change of the tumor. Fluorescein angiography only evidenced late staining of choroidal neovascularization scar, and optical coherence tomography showed a normal macular anatomy. Conclusion Intravitreal bevacizumab was effective in the treatment of choroidal neovascularization, optic nerve edema, venous dilatation, and local capillary telangiectasia, complicating an optic disk melanocytoma. PMID:25834382

  6. Inversion and uncertainty of highly parameterized models in a Bayesian framework by sampling the maximal conditional posterior distribution of parameters

    NASA Astrophysics Data System (ADS)

    Mara, Thierry A.; Fajraoui, Noura; Younes, Anis; Delay, Frederick

    2015-02-01

    We introduce the concept of maximal conditional posterior distribution (MCPD) to assess the uncertainty of model parameters in a Bayesian framework. Although, Markov Chains Monte Carlo (MCMC) methods are particularly suited for this task, they become challenging with highly parameterized nonlinear models. The MCPD represents the conditional probability distribution function of a given parameter knowing that the other parameters maximize the conditional posterior density function. Unlike MCMC which accepts or rejects solutions sampled in the parameter space, MCPD is calculated through several optimization processes. Model inversion using MCPD algorithm is particularly useful for highly parameterized problems because calculations are independent. Consequently, they can be evaluated simultaneously with a multi-core computer. In the present work, the MCPD approach is applied to invert a 2D stochastic groundwater flow problem where the log-transmissivity field of the medium is inferred from scarce and noisy data. For this purpose, the stochastic field is expanded onto a set of orthogonal functions using a Karhunen-Loève (KL) transformation. Though the prior guess on the stochastic structure (covariance) of the transmissivity field is erroneous, the MCPD inference of the KL coefficients is able to extract relevant inverse solutions.

  7. Understanding the Code: keeping accurate records.

    PubMed

    Griffith, Richard

    2015-10-01

    In his continuing series looking at the legal and professional implications of the Nursing and Midwifery Council's revised Code of Conduct, Richard Griffith discusses the elements of accurate record keeping under Standard 10 of the Code. This article considers the importance of accurate record keeping for the safety of patients and protection of district nurses. The legal implications of records are explained along with how district nurses should write records to ensure these legal requirements are met. PMID:26418404

  8. Ossification of the posterior longitudinal ligament: a clinico-radiological study of 74 cases.

    PubMed Central

    Nose, T; Egashira, T; Enomoto, T; Maki, Y

    1987-01-01

    A clinico-radiological analysis of 74 cases of ossification of the posterior longitudinal ligament is reported. Eighteen cases (24%) were asymptomatic or only had neck or shoulder pain; 16 cases (22%) showed signs of radiculopathy, and the remaining 40 cases (54%) had myelopathy. Ossification of the posterior longitudinal ligament developed most frequently at C5, and was rare in thoracic and lumbar regions. Ossification of the posterior longitudinal ligament led to stenosis of the spinal canal; more marked stenosis caused clinical myelopathy. The data showed that 30% of stenosis caused by ossification of the posterior longitudinal ligament was critical for the production of myelopathy. Images PMID:3104541

  9. Subjective probability and quantum certainty

    E-print Network

    Caves, C M; Schack, R; Caves, Carlton M.; Fuchs, Christopher A.; Schack, Ruediger

    2006-01-01

    In the Bayesian approach to quantum mechanics, probabilities--and thus quantum states--represent an agent's degrees of belief, rather than corresponding to objective properties of physical systems. In this paper we investigate the concept of certainty in quantum mechanics. Our analysis reveals fundamental differences between our Bayesian approach on the one hand and the Copenhagen interpretation and similar interpretations of quantum states on the other hand. We first review the main arguments for the general claim that probabilities always represent degrees of belief. We then show that a quantum state prepared by some physical device always depends on an agent's prior beliefs, implying that with-certainty predictions derived from such a state also depend on the agent's prior beliefs. Quantum certainty is therefore always some agent's certainty. Conversely, if facts about an experimental setup could imply certainty for a measurement outcome, that outcome would effectively correspond to a preexisting system pr...

  10. Probability, Information and Statistical Physics

    NASA Astrophysics Data System (ADS)

    Kuzemsky, A. L.

    2015-09-01

    In this short survey review we discuss foundational issues of the probabilistic approach to information theory and statistical mechanics from a unified standpoint. Emphasis is on the inter-relations between theories. The basic aim is tutorial, i.e. to carry out a basic introduction to the analysis and applications of probabilistic concepts to the description of various aspects of complexity and stochasticity. We consider probability as a foundational concept in statistical mechanics and review selected advances in the theoretical understanding of interrelation of the probability, information and statistical description with regard to basic notions of statistical mechanics of complex systems. It includes also a synthesis of past and present researches and a survey of methodology. The purpose of this terse overview is to discuss and partially describe those probabilistic methods and approaches that are used in statistical mechanics with the purpose of making these ideas easier to understanding and to apply.

  11. Ventral simultanagnosia and prosopagnosia for unfamiliar faces due to a right posterior superior temporal sulcus and angular gyrus lesion.

    PubMed

    Sakurai, Yasuhisa; Hamada, Kensuke; Tsugawa, Naoya; Sugimoto, Izumi

    2016-02-01

    We report a patient with ventral simultanagnosia, prosopagnosia for "unfamiliar faces" (dorsal prosopagnosia), spatial agraphia, and constructional disorder, particularly on the left spatial side, due to a lesion in the right posterior superior and middle temporal gyri and angular gyrus. The patient showed impairment of fundamental visual and visuospatial recognition, such as in object size, configuration, and horizontal point location, which probably underlay the mechanism of simultanagnosia and prosopagnosia. This case also suggests that the coexistence of simultanagnosia and prosopagnosia results from a right hemispheric insult, and damage to the temporoparietal area interrupts the incorporation of spatial information into object recognition. This disconnection of information flow, together with impaired object recognition per se, may impair the parallel processing of multiple objects, leading to object-by-object or part-by-part recognition. PMID:26207875

  12. Probabilities of success and failure in endodontic treatment: a Bayesian approach.

    PubMed

    Thoden van Velzen, S K; Duivenvoorden, H J; Schuurs, A H

    1981-07-01

    Bayes' theorem provides a mathematical rule for changing a (prior) probability into a new (posterior) probability incorporating additional information. Application of the theorem is a way to overcome some limitations that the human mind has in processing information. A Bayesian approach is useful for the processing of data and as a tool for decision making. Bayes' theorem is expounded, and examples are given of the use of the theorem for computing the odds on success or failure of endodontic treatment of a tooth, given a particular preoperative status and given also the results of the preparation and filling of the root canal of the tooth in question. Application of Bayes' theorem using data collected provides an insight based upon probabilities and odds in the way preoperative conditions and operative results affect the ultimate treatment result. PMID:6944684

  13. A pull out suture for transection of the posterior horn of the medial meniscus: using a posterior trans-septal portal.

    PubMed

    Ahn, Jin Hwan; Wang, Joon Ho; Yoo, Jae Chul; Noh, Haeng Kee; Park, Jung Ho

    2007-12-01

    A transection (root tear or complete radial tear) injury of the medial meniscus posterior horn is not rare in the oriental area and needs to be repaired to restore the hoop tension and to reduce the extruded meniscus, which leads to osteoarthritis of the knee. In cases with transection of the medial meniscus posterior horn, the meniscus can be repaired by a pull out suture technique. However, it is difficult to manipulate a suture hook and drill a tibial tunnel in the narrow medial joint space using the traditional anterior arthroscopic technique. This article describes a new pull out suture technique for transection of the medial meniscus posterior horn using a posterior trans-septal portal that provides a safe and wide field of vision. The handling of the suture hook and a guide may reduce the possibility of a chondral or meniscal injury. PMID:17370062

  14. Illustrating Basic Probability Calculations Using "Craps"

    ERIC Educational Resources Information Center

    Johnson, Roger W.

    2006-01-01

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

  15. Posterior Cruciate Ligament Reconstruction Using Single-Bundle Achilles Allograft with Open Tibial Inlay Fixation

    PubMed Central

    Zehir, Sinan; Elmal?, Nurzat; Çalb?y?k, Murat; Ta?demir, Zeki; Sa?lam, Fevzi

    2014-01-01

    Objectives: PCL reconstruction research has shown that the tibial inlay and transtibial tunnel procedures offer similar biomechanical results. The purpose of this study was to evaluate the early results of PCL reconstruction using a single-bundle Achilles allograft and tibial inlay fixation. Methods: We retrospectively studied 14 patients who had undergone PCL reconstruction using the direct tibial inlay fixation technique from 2009 to 2013, with a mean follow-up of 13.4 months. (6-28 months). The patients were 11males and 3 females with an average age of 29.2 years (17-41 years). Ipsilateral femoral shaft fractures were determined in 2 cases, ipsilateral trochanteric fracture in 1 case and popliteal artery injury in 1 case. Surgery was performed within 2-4 weeks. Spanning-joint external fixation was applied to 2 patients because of gross instability with failure to maintain reduction in a brace. Combined reconstructions involving the posterolateral corner (9/14), anterior cruciate ligament (ACL (11/14)), or medial collateral ligament (MCL (1/14)) were performed. All PCL reconstructions were performed with Achilles allograft. In 1 case with arterial injury, the repair was made by a cardiovascular surgeon. In 2 case, deep infection developed, which was controlled with debridement and antibiotic treatment. Superficial peroneal nerve injury in 1 case was treated with tenolysis in the 6th month, then partial healing was seen at 18 months. In all patients, the preoperative posterior drawer (PD) examination was positive. All patients were evaluated with preoperative and postoperative examination and x-rays. The International Knee Documentation Committee (IKDC) evaluation was applied to all patients at the final follow-up. Results: Postoperative PD examination demonstrated the following: 0 (normal) in 4 patients, 1+ in 7 patients, and 2+ in 3 patients, compared to the preoperative PD of 3+ or greater in all patients. Preoperative IKDC objective evaluation rated all knees as severely abnormal based on instability. The final follow-up objective IKDC evaluation distribution was as follows: A, 4 knees; B, 6 knees; C, 3 knees and D, 1 knee, compared to D in all 14 knees preoperatively. The average final follow-up IKDC subjective score was 74.1 (20-100). Conclusion: Despite transtibial PCL reconstruction being advocated by several authors, it has technical difficulties of the arthroscopic approach to the posterior compartment of the knee. In the open inlay technique, posterior arthrotomy allows accurate placement of the tibial PCL insertion, avoiding the killer curve and more closely duplicating the normal PCL anatomy. Based on our initial experience with this technique at early follow-up, we continue to use the tibial inlay technique as our preferred technique for isolated or combined reconstruction of the PCL.

  16. Cost-Effectiveness of Fluocinolone Acetonide Implant Versus Systemic Therapy for Non-infectious Intermediate, Posterior and Panuveitis

    PubMed Central

    Sugar, Elizabeth A.; Holbrook, Janet T.; Kempen, John H.; Burke, Alyce E.; Drye, Lea T.; Thorne, Jennifer E.; Louis, Thomas A.; Jabs, Douglas A.; Altaweel, Michael M.; Frick, Kevin D.

    2014-01-01

    Objective To evaluate the 3-year incremental cost-effectiveness of fluocinolone acetonide implant versus systemic therapy for the treatment of non-infectious intermediate, posterior, and panuveitis. Design Randomized, controlled, clinical trial. Participants Patients with active or recently active intermediate, posterior, or panuveitis enrolled in the Multicenter Uveitis Steroid Treatment Trial. Methods Data on cost and health-utility during 3 years post-randomization were evaluated at 6-month intervals. Analyses were stratified by disease laterality at randomization (31 unilateral vs 224 bilateral) due to the large upfront cost of the implant. Main Outcome Measures The primary outcome was the incremental cost-effectiveness ratio (ICER) over 3 years: the ratio of the difference in cost (in United States Dollars) to the difference in change in quality adjusted life years (QALYs). Costs of medications, surgeries, hospitalizations, and regular procedures (e.g. lab monitoring for systemic therapy) were included. QALYs were computed as a weighted average of EQ-5D scores over the 3 years of follow-up. Results The ICER at three years was $297,800/QALY for bilateral disease, driven by the high cost of implant therapy (Difference Implant – Systemic [?]: $16,900, p<0.001) and the modest gains in QALYs (? = 0.057, p = 0.22). The probability of the ICER being cost-effective at thresholds of $50,000/QALY and $100,000/QALY was 0.003 and 0.04, respectively. The ICER for unilateral disease was more favorable, $41,200/QALY at 3 years, due to a smaller difference in cost between the two therapies (? = $5,300, p = 0.44) and a larger benefit in QALYs with the implant (? = 0.130, p = 0.12). The probability of the ICER being cost-effective at thresholds of $50,000/QALY and $100,000/QALY was 0.53 and 0.74, respectively. Conclusion Fluocinolone acetonide implant therapy was reasonably cost-effective as compared to systemic therapy for individuals with unilateral intermediate, posterior or panuveitis but not for those with bilateral disease. These results do not apply to the use of implant therapy when systemic therapy has failed or is contraindicated. Should the duration of implant effect prove substantially longer than three years or should large changes in therapy pricing occur, the cost-effectiveness of implant versus systemic therapy would need to be re-evaluated. PMID:24908205

  17. Prevention of posterior capsular opacification through cyclooxygenase-2 inhibition

    PubMed Central

    Barden, Curtis A; Lu, Ping; Kusewitt, Donna F.; Colitz, Carmen M. H.

    2007-01-01

    Purpose To determine if cyclooxygenase-2 (COX-2) is upregulated when lens epithelial cells (LEC) in clinical samples of cataracts and posterior capsule opacification (PCO) undergo epithelial-mesenchymal transition (EMT)-like changes. We also wanted to learn if inhibition of the enzymatic activity of COX-2 could prevent PCO formation. Methods To ensure that EMT-like changes were occurring in LEC, real-time RT-PCR was used to examine expression of EMT markers. Clinical samples of canine cataracts and PCO were examined for COX-2 expression using immunohistochemistry, western blot analysis, and real-time RT-PCR. The COX-2 inhibitors, rofecoxib and celecoxib, were used in an ex vivo model of PCO formation, and the effects on cellular migration, proliferation, and apoptosis were analyzed using immunohistochemistry and western blots. Prostaglandin E2 (PGE2) expression was examined with ELISA. Results Markers of EMT, such as lumican, Snail, Slug, and COX-2 were expressed in LEC. In clinical samples of cataracts and PCO, there was overexpression of COX-2 protein and mRNA. Both rofecoxib and celecoxib were effective at inhibiting PCO formation in our ex vivo model. Prevention of PCO with the COX-2 inhibitors appeared to work through decreased migration and proliferation, and increased apoptosis. Neither of the drugs had a toxic effect on confluent LEC and appeared to inhibit PCO through their pharmacologic action. Synthesis of PGE2 was inhibiting in the capsules treated with the COX-2 inhibiting drugs. Conclusions Extracapsular phacoemulsification cataract surgery is the most common surgical procedure performed in human and veterinary ophthalmology. The most frequent postoperative complication is PCO. The LEC that remain adhered to the lens capsule undergo EMT-like changes, proliferate, and migrate across the posterior lens capsule causing opacities. We have shown that COX-2, a protein associated with EMT, is upregulated in canine cataracts and PCO. Inhibiting the enzymatic activity effectively prevented EMT of LEC in our ex vivo model of PCO through pharmacologic action, and not acute toxicity. These findings indicate that using COX-2 inhibitors in vivo may be an effective technique in preventing PCO. PMID:17563718

  18. Treatment of Surgical Site Infection in Posterior Lumbar Interbody Fusion

    PubMed Central

    Lee, Jung Su; Chang, Byung Kwon; Lee, Jae Il

    2015-01-01

    Study Design A retrospective observational and case control study. Purpose To identify appropriate treatment options according to the types of surgical site infections (SSI) in instrumented posterior lumbar interbody fusion (PLIF). Overview of Literature There has been no agreement or consensus with regard to this matter. Methods Thirty-two consecutive SSIs were included and followed for more than one year. The elapsed time to diagnosis (ETD) according to the type of SSI was analyzed. The treatment options for each type and consequent clinical results were reviewed. The risk factors of removing the implants were analyzed. Results There were 6/32 (19%) superficial incisional, 6/32 (19%) deep incisional, and 20/32 (62%) organ/space infection cases (SII, DII, and O/SI, respectively) (p=0.002). ETD was 8.5±2.3 days in SII, 8.7±2.3 days in DII, and 164.5±131.1 days in O/SI (p=0.013). All cases of SII and DII retained implants and were treated by repeated irrigation and secondary closure. Among O/SIs, 10/20 were treated conservatively. Nine out of ten underwent posterior one stage simultaneous revision (POSSR) and in one case, the cage was removed anteriorly. Those who had ETDs longer than 3 months showed a significant risk of implant removal (p=0.008, odds ratio [OR]=40.3). The Oswestry disability index (ODI) improved from 47.3% to 33.8% in SII, from 55.0% to 32.3% in DII, and from 53.4% to 42.1% in O/SI (p=0.002). There was no difference among the three groups (p=0.106); however, there was a partial correlation between ETD and final ODI (r=0.382, p=0.034). Conclusions Latent O/SI was the most common type of SSI in PLIF. In cases of SII and DII, early aggressive wound management and secondary closure was effective and implant removal was not necessary. In some cases of O/SI, implant removal was unavoidable. However, implant removal could be averted by an earlier diagnosis. POSSR was feasible and safe. Functional outcomes were improved; however, disability increased as ETD increased. PMID:26713114

  19. Supratentorial Neurometabolic Alterations in Pediatric Survivors of Posterior Fossa Tumors

    SciTech Connect

    Rueckriegel, Stefan M.; Driever, Pablo Hernaiz; Bruhn, Harald

    2012-03-01

    Purpose: Therapy and tumor-related effects such as hypoperfusion, internal hydrocephalus, chemotherapy, and irradiation lead to significant motor and cognitive sequelae in pediatric posterior fossa tumor survivors. A distinct proportion of those factors related to the resulting late effects is hitherto poorly understood. This study aimed at separating the effects of neurotoxic factors on central nervous system metabolism by using H-1 MR spectroscopy to quantify cerebral metabolite concentrations in these patients in comparison to those in age-matched healthy peers. Methods and Materials: Fifteen patients with World Health Organization (WHO) I pilocytic astrocytoma (PA) treated by resection only, 24 patients with WHO IV medulloblastoma (MB), who additionally received chemotherapy and craniospinal irradiation, and 43 healthy peers were investigated using single-volume H-1 MR spectroscopy of parietal white matter and gray matter. Results: Concentrations of N-acetylaspartate (NAA) were significantly decreased in white matter (p < 0.0001) and gray matter (p < 0.0001) of MB patients and in gray matter (p = 0.005) of PA patients, compared to healthy peers. Decreased creatine concentrations in parietal gray matter correlated significantly with older age at diagnosis in both patient groups (MB patients, p = 0.009, r = 0.52; PA patients, p = 0.006, r = 0.7). Longer time periods since diagnosis were associated with lower NAA levels in white matter of PA patients (p = 0.008, r = 0.66). Conclusions: Differently decreased NAA concentrations were observed in both PA and MB groups of posterior fossa tumor patients. We conclude that this reflects a disturbance of the neurometabolic steady state of normal-appearing brain tissue due to the tumor itself and to the impact of surgery in both patient groups. Further incremental decreases of metabolite concentrations in MB patients may point to additional harm caused by irradiation and chemotherapy. The stronger decrease of NAA in MB patients may correspond to the additional damage of combined irradiation and chemotherapy on neuroaxonal cell viability and number.

  20. Probability for Weather and Climate

    NASA Astrophysics Data System (ADS)

    Smith, L. A.

    2013-12-01

    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.

  1. Eye Can See What You Want: Posterior Intraparietal Sulcus Encodes the Object of an Actors Gaze

    E-print Network

    Hamilton, Antonia

    Eye Can See What You Want: Posterior Intraparietal Sulcus Encodes the Object of an Actors Gaze for gazed object in the human condition was found in posterior intraparietal sulcus (pIPS). RS sulcus (IPS) have been as- sociated with different functional processes during gaze perception (Nummenmaa

  2. Neuropsychologia 42 (2004) 14351446 A region of right posterior superior temporal sulcus responds

    E-print Network

    Kanwisher, Nancy

    2004-01-01

    Neuropsychologia 42 (2004) 1435­1446 A region of right posterior superior temporal sulcus responds of the right posterior superior temporal sulcus that is sensitive not to articulated body motion per se temporal sulcus; Neuroimaging; Biological motion 1. Introduction Both adults and infants can perceive

  3. Behavioral/Systems/Cognitive Human Posterior Parietal Cortex Plans Where to Reach

    E-print Network

    Crawford, Doug

    Behavioral/Systems/Cognitive Human Posterior Parietal Cortex Plans Where to Reach and What to Avoid visually guided motor behavior. Specifically, we asked whether human posterior parietal cortex has at the level of parietal neurons, comparatively little support is provided by recent human imaging experiments

  4. Fracture of the Posterior Process of the Talus With Concomitant Subtalar Dislocation.

    PubMed

    Park, Chul Hyun; Park, Kang Hyun

    2016-01-01

    Fracture of the posterior process of the talus with concomitant subtalar dislocation is rare; thus, the mechanism of injury, appropriate treatment, and prognosis are unclear. We report the case of a 50-year-old male with a fracture of the posterior process of the talus with concomitant subtalar dislocation that was recognized early and successfully treated operatively. PMID:26213161

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

    SciTech Connect

    Hagspiel, Klaus D.; Bonatti, Hugo; Sabri, Saher; Arslan, Bulent; Harthun, Nancy L.

    2011-04-15

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

  6. Cosmological parameter inference from galaxy clustering: the effect of the posterior distribution of the power spectrum

    NASA Astrophysics Data System (ADS)

    Kalus, B.; Percival, W. J.; Samushia, L.

    2016-01-01

    We consider the shape of the posterior distribution to be used when fitting cosmological models to power spectra measured from galaxy surveys. At very large scales, Gaussian posterior distributions in the power do not approximate the posterior distribution P_R we expect for a Gaussian density field ? k, even if we vary the covariance matrix according to the model to be tested. We compare alternative posterior distributions with P_R, both mode-by-mode and in terms of expected measurements of primordial non-Gaussianity parametrized by fNL. Marginalising over a Gaussian posterior distribution P_f with fixed covariance matrix yields a posterior mean value of fNL which, for a data set with the characteristics of Euclid, will be underestimated by ?fNL = 0.4, while for the data release 9 of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS DR9; Ahn et al.) it will be underestimated by ?fNL = 19.1. Adopting a different form of the posterior function means that we do not necessarily require a different covariance matrix for each model to be tested: this dependence is absorbed into the functional form of the posterior. Thus, the computational burden of analysis is significantly reduced.

  7. Multiple Looping Technique for Tibial Fixation in Posterior Cruciate Ligament Reconstruction of the Knee

    PubMed Central

    Noh, Jung Ho; Yoon, Kyoung Ho; Song, Sang Jun; Roh, Young Hak; Lee, Jae Woo

    2015-01-01

    The outcomes of posterior cruciate ligament reconstruction may be negatively affected by insufficient tibial tunnel fixation due to relatively lower bone density of the proximal tibia. We introduce a new technique of tibial fixation for posterior cruciate ligament reconstruction using free tendon Achilles allograft that is less affected by the bone density of the tibial metaphysis. PMID:25973367

  8. Mutual Information and Posterior Estimates in Channels of Exponential Family Type

    E-print Network

    Raginsky, Maxim

    Mutual Information and Posterior Estimates in Channels of Exponential Family Type Maxim Raginsky-theoretic properties of various noisy channel models. For example, Guo, Shamai, and Verd´u have shown that mutual representations of the mutual information and the posterior information gain that are valid for any E-type channel

  9. Nonanatomic Location of the Posterior Horn of a Medial Meniscal Autograft

    E-print Network

    Hull, Maury

    tunnel of a medial meniscal transplant within a tolerance tighter than 5 mm medial and 5 mm posterior of the posterior horn may oc- cur during arthroscopic implantation of a meniscal transplant. The objective. The goal of medial meniscal transplantation is to prevent degenerative changes that can result from

  10. POSTERIOR-BASED CONFIDENCE MEASURES FOR SPOKEN TERM DETECTION , Javier Tejedor1,2

    E-print Network

    Edinburgh, University of

    . The confidence measure expresses the posterior proba- bility of the search term appearing in the detection periodPOSTERIOR-BASED CONFIDENCE MEASURES FOR SPOKEN TERM DETECTION Dong Wang1 , Javier Tejedor1,2 , Joe Madrid, Spain ABSTRACT Confidence measures play a key role in spoken term detection (STD) tasks

  11. FKBP5 Genotype and Structural Integrity of the Posterior Cingulum

    PubMed Central

    Fani, Negar; King, Tricia Z; Reiser, Emily; Binder, Elisabeth B; Jovanovic, Tanja; Bradley, Bekh; Ressler, Kerry J

    2014-01-01

    Alterations in the microarchitecture of the posterior cingulum (PC), a white matter tract proximal to the hippocampus that facilitates communication between the entorhinal and cingulate cortices, have been observed in individuals with psychiatric disorders, such as depression and post-traumatic stress disorder (PTSD). PC decrements may be a heritable source of vulnerability for the development of affective disorders; however, genetic substrates for these white matter abnormalities have not been identified. The FKBP5 gene product modulates glucocorticoid receptor function and has been previously associated with differential hippocampal structure, function, and affect disorder risk. Thus, FKBP5 is an attractive genetic target for investigations of PC integrity. We examined associations between PC integrity, measured through diffusion tensor imaging (DTI) and fractional anisotropy (FA; an index of white matter integrity), and polymorphisms in the FKBP5 SNP rs1360780 in a sample of 82 traumatized female civilians. Findings indicated that, compared with individuals without this allele, individuals who carried two ‘risk' alleles for this FKBP5 SNP (T allele; previously associated with mood and anxiety disorder risk) demonstrated significantly lower FA in the left PC, even after statistically controlling for variance associated with age, trauma exposure, and PTSD symptoms. These data suggest that specific allelic variants for an FKBP5 polymorphism are associated with decrements in the left PC microarchitecture. These white matter abnormalities may be a heritable biological marker that indicates increased vulnerability for the development of psychiatric disorders, such as PTSD. PMID:24253961

  12. Visual-Manual Exploration and Posterior Parietal Cortex in Humans

    PubMed Central

    Hinkley, Leighton B. N.; Krubitzer, Leah A.; Padberg, Jeff

    2009-01-01

    Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities. PMID:19812283

  13. Hypertension-induced reversible posterior leukoencephalopathy syndrome causing obstructive hydrocephalus.

    PubMed

    Lee, S Y; Dinesh, S K; Thomas, J

    2008-04-01

    Reversible posterior leukoencephalopathy syndrome (RPLS) is characterized clinically by headache, altered mental status, abnormal visual perception and seizures. It is associated with neuroradiological findings characterized by reversible white matter abnormalities, predominantly in the parietal-occipital areas. Since the first description in 1996, it has been recognized in an increasing number of medical conditions, including hypertensive encephalopathy, eclampsia, and immunosuppressive treatment. The rapid resolution of clinical and neuroradiologic abnormalities suggests cerebral oedema, which is thought to result from impaired cerebrovascular autoregulation and endothelial injury. We report a patient presenting with acute onset progressively worsening headache and confusion associated with uncontrolled hypertension. CT and MRI revealed acute non-communicating hydrocephalus secondary to cerebellar and pontine oedema. The patient became drowsy, so an external ventricular drain was inserted for decompression of the acute hydrocephalus, and his blood pressure was aggressively managed. The patient recovered well with complete clinical and radiological resolution. This case illustrates the reversibility of RPLS if it is diagnosed early and appropriate treatment is instituted. PMID:18249121

  14. Motor features in posterior cortical atrophy and their imaging correlates.

    PubMed

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

    2014-12-01

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

  15. Posterior Tibial Tendon Insufficiency Results at Different Stages

    PubMed Central

    Page, Alexandra; Sung, Il-Hoon; O’Malley, Martin J.; Inda, David; Choung, Steven

    2006-01-01

    The results of surgical treatment of posterior tibial tendon insufficiency (PTTI) may be different at different stages of the disease. No single study has compared the results at different stages. This comparison can be helpful to the patient and physician if the patient asks “What if I wait and the disease progresses, how will my results be different?” A preliminary study comparing results for stage IIa, stage IIb (advanced stage II), and stage III was performed followed by a larger study comparing IIa and IIb with 26 and 22 patients, respectively. American Orthopaedic Foot and Ankle Society (AOFAS) outcome scores as well as radiographs and functional questions were used. Nearly all patients, regardless of stage, felt they were helped by surgical treatment. However, the lowest AOFAS score was in stage III, the most advanced stage investigated in this study. In comparing stage IIa and IIb patients, stage IIb patients had a statistically higher incidence of lateral discomfort. Although statistically significant differences were not found in all comparisons, this study suggests that the results of surgical treatment for PTTI declines with increasing stage or severity of disease. PMID:18751830

  16. Cementation of Glass-Ceramic Posterior Restorations: A Systematic Review

    PubMed Central

    van den Breemer, Carline R. G.; Gresnigt, Marco M. M.; Cune, Marco S.

    2015-01-01

    Aim. The aim of this comprehensive review is to systematically organize the current knowledge regarding the cementation of glass-ceramic materials and restorations, with an additional focus on the benefits of Immediate Dentin Sealing (IDS). Materials and Methods. An extensive literature search concerning the cementation of single-unit glass-ceramic posterior restorations was conducted in the databases of MEDLINE (Pubmed), CENTRAL (Cochrane Central Register of Controlled Trials), and EMBASE. To be considered for inclusion, in vitro and in vivo studies should compare different cementation regimes involving a “glass-ceramic/cement/human tooth” complex. Results and Conclusions. 88 studies were included in total. The in vitro data were organized according to the following topics: (micro)shear and (micro)tensile bond strength, fracture strength, and marginal gap and integrity. For in vivo studies survival and quality of survival were considered. In vitro studies showed that adhesive systems (3-step, etch-and-rinse) result in the best (micro)shear bond strength values compared to self-adhesive and self-etch systems when luting glass-ceramic substrates to human dentin. The highest fracture strength is obtained with adhesive cements in particular. No marked clinical preference for one specific procedure could be demonstrated on the basis of the reviewed literature. The possible merits of IDS are most convincingly illustrated by the favorable microtensile bond strengths. No clinical studies regarding IDS were found. PMID:26557651

  17. Proteomic profiling of posterior longitudinal ligament of cervical spine

    PubMed Central

    Zhang, Ying; Liu, Baifeng; Shao, Jiang; Song, Jia; Zhang, Jing

    2015-01-01

    Objective: To identify putative biomarkers for ossification of posterior longitudinal ligament (OPLL). Material and methods: Proteomic analysis was performed in 4 ligament samples from OPLL patients and healthy controls. RT-PCR was used to further verify the proteomic analysis results. Results: A total of 50 differentially expressed spots were detected in 2-D electrophoresis between the two groups. In protein/peptide analysis, 21 proteins or peptides were finally identified. Besides 13 hematic proteins and 2 unknown proteins, 6 other proteins were differentially expressed. Among them, carbonic anhydrase I, NAD(P) dependent steroid dehydrogenase-like, billiverdin reductase B and alpha-1 collagen VI were down-regulated, while osteoglycin and nebulin-related anchoring protein were up-regulated. The results of NAD(P) dependent steroid dehydrogenase-like, alpha-1 collagen VI and nebulin-related anchoring protein were validated by RT-PCR. Conclusion: These differentially expressed proteins could play a role in the onset and progression of OPLL. PMID:26131146

  18. Predictive factors and outcomes of posterior segment intraocular foreign bodies

    PubMed Central

    Choovuthayakorn, J; Hansapinyo, L; Ittipunkul, N; Patikulsila, D; Kunavisarut, P

    2011-01-01

    Purpose To identify the predictive factors for anatomical and visual outcomes in posterior segment intraocular foreign body (IOFB) patients managed by pars plana vitrectomy (PPV). Methods A retrospective chart review was performed for 77 patients, who had PPV for IOFBs removal between January 2001 and July 2007. Univariate and multivariate analyses were conducted to evaluate the predictive factors. Results The mean age of the patients was 33.4 years. The nature of IOFBs was mainly metal, with injuries most commonly caused by an electric grass trimmer. The mean time interval between injury and IOFBs removal was 30.7 days. The mean preoperative visual acuity (VA) was 1.82 logarithm of the minimal angle of resolution (logMAR), and mean final was VA 1.10 logMAR. From multivariate analysis, good visual outcome was correlated with the corneoscleral entry site, and poor visual outcome was correlated with the presence of relative afferent pupillary defect. Conclusions In noncombat IOFBs, most cases were work-related. Delayed IOFBs removal was acceptable when primary wounds were repaired appropriately and extensive antibiotics administered. Even though advancement in vitreoretinal surgery can reduce the frequency of blindness, further promotion and education on eye protection during work are needed. PMID:21921948

  19. Bicondylar tibial plateau fracture after posterior cruciate ligament reconstruction.

    PubMed

    Griesser, Michael J; McCoy, Brett W; Hussain, Waqas M; Saluan, Paul

    2015-03-01

    The authors present a report of a bicondylar tibial plateau fracture in an adolescent athlete after posterior cruciate ligament (PCL) reconstruction. The procedure was performed via arthroscopic transtibial PCL reconstruction with quadrupled semi-tendinosus and gracilis autograft. The patient recovered uneventfully postoperatively and was able to participate in high-level sports activity, such as baseball and track, with no limitations, no subjective complaints, and no episodes of instability. He continued to be asymptomatic up to 3.5 years postoperatively. Almost 4 years postoperatively, the patient reinjured the left knee during recreational noncontact football and was seen emergently. Plain radiographs, magnetic resonance image scan, and computed tomography scan at the time of injury showed a bicondylar tibial plateau fracture with intra-articular involvement. Operative intervention was undertaken for open reduction and internal fixation of the bicondylar tibial plateau fracture. A plate was placed along the medial aspect of the tibia with locking and nonlocking screws, and the joint line was restored appropriately. The patient recovered uneventfully and at the most recent follow-up had full active and passive range of motion, had no subjective or objective evidence of instability, and had returned to full activity with no restrictions. The patient had no history of multiple fractures or any medical or pharmacologic history that predisposed him to decreased bone density. This case shows a unique possible complication after transtibial PCL reconstruction in an adolescent patient. PMID:25760514

  20. Interspinous posterior devices: What is the real surgical indication?

    PubMed Central

    Landi, Alessandro

    2014-01-01

    Interspinous posterior device (IPD) is a term used to identify a relatively recent group of implants used to treat lumbar spinal degenerative disease. This kind of device is classified as part of the group of the dynamic stabilization systems of the spine. The concept of dynamic stabilization has been replaced by that of dynamic neutralization of hypermobility, with the intention of clarifying that the primary aim of this kind of system is not the preservation of the movement, but the dynamic neutralization of the segmental hypermobility which is at the root of the pathological condition. The indications for the implantation of an IPD are spinal stenosis and neurogenic claudication, assuming that its function is the enlargement of the neural foramen and the decompression of the roots forming the cauda equina in the central part of the vertebral canal. In the last 10 years, use of these implants has been very common but to date, no long-term clinical follow-up regarding clinical and radiological aspects are available. The high rate of reoperation, recurrence of symptoms and progression of degenerative changes is evident in the literature. If these devices are effectively a miracle cure for lumbar spinal stenosis, why do the utilization and implantation of IPD remain extremely controversial and should they be investigated further? Excluding the problems related to the high cost of the device, the main problem remains the pathological substrate on which the device is explicit in its action: the degenerative pathology of the spine. PMID:25232541

  1. A novel function for Egr4 in posterior hindbrain development

    PubMed Central

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

    2015-01-01

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

  2. Hox gene duplications correlate with posterior heteronomy in scorpions

    PubMed Central

    Sharma, Prashant P.; Schwager, Evelyn E.; Extavour, Cassandra G.; Wheeler, Ward C.

    2014-01-01

    The evolutionary success of the largest animal phylum, Arthropoda, has been attributed to tagmatization, the coordinated evolution of adjacent metameres to form morphologically and functionally distinct segmental regions called tagmata. Specification of regional identity is regulated by the Hox genes, of which 10 are inferred to be present in the ancestor of arthropods. With six different posterior segmental identities divided into two tagmata, the bauplan of scorpions is the most heteronomous within Chelicerata. Expression domains of the anterior eight Hox genes are conserved in previously surveyed chelicerates, but it is unknown how Hox genes regionalize the three tagmata of scorpions. Here, we show that the scorpion Centruroides sculpturatus has two paralogues of all Hox genes except Hox3, suggesting cluster and/or whole genome duplication in this arachnid order. Embryonic anterior expression domain boundaries of each of the last four pairs of Hox genes (two paralogues each of Antp, Ubx, abd-A and Abd-B) are unique and distinguish segmental groups, such as pectines, book lungs and the characteristic tail, while maintaining spatial collinearity. These distinct expression domains suggest neofunctionalization of Hox gene paralogues subsequent to duplication. Our data reconcile previous understanding of Hox gene function across arthropods with the extreme heteronomy of scorpions. PMID:25122224

  3. [VEGETATIVE REACTIONS AS PROGNOSTIC FACTOR IN POSTERIOR FOSSA SURGERY].

    PubMed

    Nazarov, R V; Kondrat'ev, A N

    2015-01-01

    Mortality rate related to posterior fossa tumors resection varies from 1 to 8 percent, according to various authors. It depends on tumor size and its growth characteristics. To determine the physiological acceptability of surgery, physiological significance of vegetative reactions associated with tumors resection has to be assessed. We divide these reactions (centrogenic reactions - CR) into 2 main groups. The first group has a relatively precise morphofunctional structure, similar to the classic reflex arc. They appear due to irritation of local centers or cranial nerves nuclei with mixed motor-vegetative structure. In most cases they are not connected with anatomic damage of CNS structures. The second group of CR is correlated with dysfunction of brain and represents brain s attempt to turn into a new functional state. Their presence should be considered as a functional degradation symptom, which might be even irreversible. Emergence from anesthesia in the operative room is not recommended in this clinical situation. Neurovegetative stabilization should be provided for a period of 6 to 24 hours after tumor resection. PMID:26596024

  4. Posterior reversible encephalopathy syndrome in children with kidney disease

    PubMed Central

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

    2014-01-01

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

  5. The spectrum of posterior reversible encephalopathy in systemic lupus erythematosus.

    PubMed

    Budhoo, Amritha; Mody, Girish M

    2015-12-01

    Our aim was to compare our South African cohort of systemic lupus erythematosus (SLE) and posterior reversible encephalopathy syndrome (PRES) with other published series. We reviewed the records of 10 patients with SLE and PRES seen over a 10-year period and their demographic data, clinical manifestations, laboratory tests, imaging findings, and outcome were recorded. We identified 10 females who included six Indians, three mixed ethnicity, and one African Black. Three patients had PRES at the onset of SLE. The most common manifestations at presentation were seizures (100 %), hypertension (80 %), and altered mental state (50 %). On neuroimaging, nine patients had bilateral involvement, and the occipital (90 %), parietal (90 %), and frontal lobes (50 %) were most commonly involved. The risk factors for PRES were disease activity (90 %), renal disease (80 %) and hypertension (80 %). Ninety percent of the patients were on immunosuppressive therapy. Immunosuppressive therapy was increased in six patients (60 %), continued in two and reduced in two patients after the diagnosis of PRES. Seven patients recovered completely and three patients died from co-morbidities. A review of the larger case series of SLE and PRES showed that the presentation and neuroimaging findings were similar; most patients had active disease at the time of PRES and the majority of patients required intensification of immunosuppressive therapy. We have shown that the majority of patients with SLE have active disease at the time of PRES, and they require an increase in their immunosuppressive therapy. PMID:26298534

  6. Gaze-dependent topography in human posterior parietal cortex.

    PubMed

    Connolly, Jason D; Vuong, Quoc C; Thiele, Alexander

    2015-06-01

    The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations "around the clock." Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations. PMID:24351977

  7. Cerebrospinal Fluid Biomarkers and Cerebral Atrophy in Distinct Clinical Variants of Probable Alzheimer’s Disease

    PubMed Central

    Ossenkoppele, Rik; Mattsson, Niklas; Teunissen, Charlotte E.; Barkhof, Frederik; Pijnenburg, Yolande; Scheltens, Philip; van der Flier, Wiesje M.; Rabinovici, Gil D.

    2015-01-01

    Different clinical variants of probable Alzheimer’s disease (AD) share underlying plaques and tangles but show distinct atrophy patterns. We included 52 posterior cortical atrophy (PCA), 29 logopenic variant primary progressive aphasia (lvPPA), 53 early-onset (EOAD) and 42 late-onset AD (LOAD) patients, selected for abnormal CSF-A?42, with CSF and MRI data available. Bootstrapping revealed no differences in the prevalence of abnormal CSF total-tau and phosphorylated-tau between probable AD variants (range total-tau: 84.9–92.3%, phosphorylated-tau: 79.2–93.1%, p>0.05). Voxel-wise linear regressions showed various relationships between lower CSF-A?42 and syndrome-specific atrophy, involving precuneus, posterior cingulate, and medial temporal lobe (MTL) in EOAD, occipital cortex and middle temporal gyrus in PCA; anterior cingulate, insular cortex and precentral gyrus (left>right) in lvPPA; and MTL, thalamus, and temporal pole in LOAD (all at p<0.001 uncorrected). In contrast, CSF-tau was not related to gray matter atrophy in any group. Our findings suggest that lower CSF-A?42 – and not increased total-tau and phosphorylated-tau – relates to reduced gray matter volumes, mostly in regions that are typically atrophied in distinct clinical variants of probable AD. PMID:25990306

  8. Management of posterior capsule rupture during phacoemulsification using the dry technique.

    PubMed

    Akura, J; Hatta, S; Kaneda, S; Ishihara, M; Matsuura, K; Tamai, A

    2001-07-01

    To manage posterior capsule rupture during phacoemulsification, we use a dry technique in which all procedures are performed without an irrigation/aspiration system. The dry technique is characterized by (1) continuous viscoelastic injection instead of fluid irrigation to maintain anterior chamber depth with the posterior capsule and vitreous located posteriorly and (2) static removal of most residual lens material by viscoexpression and/or manual small incision extracapsular cataract extraction without aspiration and dynamic water flow. In 16 cases of posterior capsule rupture managed using the dry technique, the residual nucleus and cortex were readily removed with minimum extension of the ruptured area and new vitreous loss. Although large amounts of viscoelastic material (mean 5.8 mL) were required, rapid and stable visual recovery was comparable to that in patients having uneventful surgery. The dry system is a safe and reliable technique for managing posterior capsule rupture during phacoemulsification. PMID:11489564

  9. A Case of Simultaneous Unilateral Anterior and Posterior Stafne Bone Defects

    PubMed Central

    Ozaki, Hisashi; Ishikawa, Shigeo; Kitabatake, Kenichirou; Yusa, Kazuyuki; Tachibana, Hirohiko; Iino, Mitsuyoshi

    2015-01-01

    Stafne bone defects (SBDs) are asymptomatic mandibular lingual bone depressions mainly caused by soft tissue inclusions. The most common form of SBDs is posterior; the anterior variant of SBD is relatively uncommon. Although posterior SBD is easily diagnosed by the unique location on radiography, anterior SBD is sometimes misdiagnosed and confused with other pathological entities owing to the location. We report herein a case of simultaneous unilateral anterior and posterior SBDs. In the present case, definitive diagnosis for the anterior mandibular cavity was unclear, as in reported cases. Surgical exploration was thus performed for the lesion in the anterior mandibular cavity. Pathologic examination of the removed tissue showed salivary gland with chronic inflammation. Postoperatively, no functional disturbance has been observed. Management of the posterior SBD was conservative, with radiographic follow-up. To the best of our knowledge, this represents the first report of simultaneous unilateral anterior and posterior SBDs. PMID:26605094

  10. Lectures on probability and statistics

    SciTech Connect

    Yost, G.P.

    1984-09-01

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

  11. Differences in the TGF-?1–Induced Profibrotic Response of Anterior and Posterior Corneal Keratocytes In Vitro

    PubMed Central

    Swanton, Jennifer N.; Phipps, Richard P.; Sime, Patricia J.; Huxlin, Krystel R.

    2010-01-01

    Purpose. To characterize phenotypic differences between anterior and posterior corneal keratocytes after stimulation with the profibrotic agent transforming growth factor-beta1 (TGF-?1) in vitro. Methods. Sixteen corneas from healthy felines were obtained immediately after death. Lamellar dissection was performed to separate the anterior and posterior stroma at approximately 50% depth either manually (n = 2) or with a Moria microkeratome (300-?m head; n = 14). Cells from the anterior and posterior stroma were cultured separately but under identical conditions. Using immunohistochemistry and Western blot techniques, Ki-67 staining and relative expression of Thy-1, alpha smooth muscle actin (?-SMA), and fibronectin were assessed after stimulation with different TGF-?1 concentrations. In addition, anterior and posterior cells cultured in different concentrations of TGF-?1 were wounded with a razor blade, and the wound area and time to closure were determined. Results. Stimulation by all concentrations of TGF-?1 increased the proportion of Ki-67–positive cells in anterior and posterior cell cultures, but this increase was noted earlier in posterior cells than in anterior cells. Increasing TGF-?1 concentration also increased the relative expression of Thy-1, ?-SMA, and fibronectin in anterior and posterior fibroblasts. However, anterior cells expressed these fibrotic markers at lower TGF-?1 concentrations than did posterior keratocytes. After mechanical wounding, posterior cells closed the wound area faster than did anterior cells at all concentrations of TGF-?1. Conclusions. The present experiments show that anterior and posterior corneal keratocytes exhibit different sensitivities to the profibrotic growth factor TGF-?1. This heterogeneity of keratocyte response may impact wound closure after mechanical wounding. PMID:19907023

  12. Avoiding Negative Probabilities in Quantum Mechanics

    E-print Network

    Nyambuya, Golden Gadzirayi

    2013-01-01

    As currently understood since its discovery, the bare Klein-Gordon theory consists of negative quantum probabilities which are considered to be physically meaningless if not outright obsolete. Despite this annoying setback, these negative probabilities are what led the great Paul Dirac in 1928 to the esoteric discovery of the Dirac Equation. The Dirac Equation led to one of the greatest advances in our understanding of the physical world. In this reading, we ask the seemingly senseless question, "Do negative probabilities exist in quantum mechanics?" In an effort to answer this question, we arrive at the conclusion that depending on the choice one makes of the quantum probability current, one will obtain negative probabilities. We thus propose a new quantum probability current of the Klein-Gordon theory. This quantum probability current leads directly to positive definite quantum probabilities. Because these negative probabilities are in the bare Klein-Gordon theory, intrinsically a result of negative energie...

  13. RNA-Catalyzed RNA Polymerization: Accurate and

    E-print Network

    Bartel, David

    for general polymerization (7). De- rivatives of self-splicing introns are able to join oligonucleotidesRNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension Wendy K. Johnston, Peter J. Unrau,* Michael S. Lawrence, Margaret E. Glasner, David P. Bartel The RNA world

  14. LETTERS TO NATURE Accurate prediction of the

    E-print Network

    Levitt, Michael

    LETTERS TO NATURE Accurate prediction of the stability and activity effects of site to be more stable than the wild type. Free-energy stability calculations for several single-site muta- tions-chains allowed to move in the prediction is shown as solid lines (predicted wild-type structure (thin lines

  15. APT: Accurate Outdoor Pedestrian Tracking with Smartphones

    E-print Network

    Li, Qun

    APT: Accurate Outdoor Pedestrian Tracking with Smartphones Xiaojun Zhu, Qun Li, Guihai Chen§ State pedestrians with smartphones. APT performs better than the built-in GPS module of the smartphone in terms for map matching. When the user is walking with the smartphone, the dead reckoning algorithm monitors

  16. Accurate Electrothermal Modeling of Thermoelectric Generators

    E-print Network

    Pedram, Massoud

    Accurate Electrothermal Modeling of Thermoelectric Generators Mohammad Javad Dousti1 , Antonio Janeiro, Brazil 1 {dousti,pedram}@usc.edu and 2 antonio@pads.ufrj.br Abstract--Thermoelectric generators of thermoelectric generators (TEGs). TEGs work based on the Seebeck effect, which converts a temperature gradient

  17. Fast and Accurate Business Process Drift Detection

    E-print Network

    Liang, Huizhi "Elly"

    Fast and Accurate Business Process Drift Detection Abderrahmane Maaradji1 , Marlon Dumas2.larosa,alireza.ostovar}@qut.edu.au Abstract. Business processes are prone to continuous and unexpected changes. Process workers may start or regulations for example. Early detection of business process changes based on their event logs ­ also known

  18. Accurate pointing of tungsten welding electrodes

    NASA Technical Reports Server (NTRS)

    Ziegelmeier, P.

    1971-01-01

    Thoriated-tungsten is pointed accurately and quickly by using sodium nitrite. Point produced is smooth and no effort is necessary to hold the tungsten rod concentric. The chemically produced point can be used several times longer than ground points. This method reduces time and cost of preparing tungsten electrodes.

  19. Accurate Assessment--Compelling Evidence for Practice

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  20. Accurate Weather Forecasting for Radio Astronomy

    E-print Network

    Groppi, Christopher

    Accurate Weather Forecasting for Radio Astronomy Ronald J Maddalena October, 2009 #12;Outline Very-3 days #12;The influence of the weather at cm- and mm-wavelengths Opacity Calibration System, telescope productivity Past conditions Calibration Weather statistics Telescope productivity, hardware

  1. Do Workers Accurately Perceive Gender Wage Discrimination?

    ERIC Educational Resources Information Center

    Hampton, Mary B.; Heywood, John S.

    1993-01-01

    Analysis of data from 529 female and 1,343 male physicians found a strong positive correlation between women's perceptions of the gender income differences they experienced and econometric estimates of those differences. Women accurately perceived wage discrimination and used their perception in determining the amount they were underpaid. (SK)

  2. Intermediate-Term Comparison of Posterior Cruciate-Retaining Versus Posterior-Stabilized Total Knee Arthroplasty Using the New Knee Scoring System.

    PubMed

    Kawakami, Yohei; Matsumoto, Tomoyuki; Takayama, Koji; Ishida, Kazunari; Nakano, Naoki; Matsushita, Takehiko; Kuroda, Yuichi; Patel, Kunji; Kuroda, Ryosuke; Kurosaka, Masahiro

    2015-12-01

    With the dramatic shift in the proportion of younger and more active patients undergoing total knee arthroplasty (TKA), the difference in patient-reported outcomes between cruciate-retaining and posterior-stabilized prostheses will become very important. The goal of this study was to clarify and compare the intermediate-term results of cruciate-retaining and posterior-stabilized TKAs with new patient-derived scores. This study included 60 patients who underwent TKA because of varus-type osteoarthritis (30 patients in the cruciate-retaining group and 30 patients in the posterior-stabilized group) an average of 8 years earlier. The authors investigated patient-reported outcomes using the Knee Society's new scoring system, which was adapted to the diverse lifestyles and activities of contemporary patients undergoing TKA. The results of 48 patients (23 patients in the cruciate-retaining group and 25 patients in the posterior-stabilized group) were assessed. The questionnaire included 7 sections: symptoms, patient satisfaction, patient expectation, walking/standing, standard activities, advanced activities, and discretionary activities. For patient satisfaction, the score of the cruciate-retaining group was slightly but not significantly higher than that of the posterior-stabilized group. No significant difference in score was seen between the cruciate-retaining group and the posterior-stabilized group for any other sections. In addition, no statistically significant difference was seen in range of motion or radiographic alignment postoperatively. After intermediate-term follow-up, the authors found no statistically significant difference in clinical outcomes between patients undergoing cruciate-retaining TKA and those undergoing posterior-stabilized TKA. Additional studies are needed to corroborate and validate these results. [Orthopedics. 2015; 38(12):e1127-e1132.]. PMID:26652335

  3. Neural correlates of learning and trajectory planning in the posterior parietal cortex

    PubMed Central

    Torres, Elizabeth B.; Quian Quiroga, Rodrigo; Cui, He; Buneo, Christopher A.

    2013-01-01

    The posterior parietal cortex (PPC) is thought to play an important role in the planning of visually-guided reaching movements. However, the relative roles of the various subdivisions of the PPC in this function are still poorly understood. For example, studies of dorsal area 5 point to a representation of reaches in both extrinsic (endpoint) and intrinsic (joint or muscle) coordinates, as evidenced by partial changes in preferred directions and positional discharge with changes in arm posture. In contrast, recent findings suggest that the adjacent medial intraparietal area (MIP) is involved in more abstract representations, e.g., encoding reach target in visual coordinates. Such a representation is suitable for planning reach trajectories involving shortest distance paths to targets straight ahead. However, it is currently unclear how MIP contributes to the planning of other types of trajectories, including those with various degrees of curvature. Such curved trajectories recruit different joint excursions and might help us address whether their representation in the PPC is purely in extrinsic coordinates or in intrinsic ones as well. Here we investigated the role of the PPC in these processes during an obstacle avoidance task for which the animals had not been explicitly trained. We found that PPC planning activity was predictive of both the spatial and temporal aspects of upcoming trajectories. The same PPC neurons predicted the upcoming trajectory in both endpoint and joint coordinates. The predictive power of these neurons remained stable and accurate despite concomitant motor learning across task conditions. These findings suggest the role of the PPC can be extended from specifying abstract movement goals to expressing these plans as corresponding trajectories in both endpoint and joint coordinates. Thus, the PPC appears to contribute to reach planning and approach-avoidance arm motions at multiple levels of representation. PMID:23730275

  4. MSPI False Indication Probability Simulations

    SciTech Connect

    Dana Kelly; Kurt Vedros; Robert Youngblood

    2011-03-01

    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.

  5. Feedback about More Accurate versus Less Accurate Trials: Differential Effects on Self-Confidence and Activation

    ERIC Educational Resources Information Center

    Badami, Rokhsareh; VaezMousavi, Mohammad; Wulf, Gabriele; Namazizadeh, Mahdi

    2012-01-01

    One purpose of the present study was to examine whether self-confidence or anxiety would be differentially affected by feedback from more accurate rather than less accurate trials. The second purpose was to determine whether arousal variations (activation) would predict performance. On Day 1, participants performed a golf putting task under one of…

  6. Posterior archaeomagnetic dating for the early Medieval site Thunau am Kamp, Austria

    NASA Astrophysics Data System (ADS)

    Schnepp, Elisabeth; Lanos, Philippe; Obenaus, Martin

    2014-05-01

    The early medieval site Thunau am Kamp consists of a hill fort and a settlement with large burial ground at the bank of river Kamp. All these features are under archaeological investigation since many years. The settlement comprises many pit houses, some with stratigraphic order. Every pit house was equipped with at least one cupola oven and/or a hearth or fireplace. Sometimes the entire cupola was preserved. The site was occupied during the 9th and 10th AD according to potshards which seem to indicate two phases: In the older phase ovens were placed in the corner of the houses while during the younger phase they are found in the middle of the wall. In order to increase the archaeomagnetic data base 14 ovens have been sampled. They fill the temporal gap in the data base for Austria around 900 AD. Laboratory treatment included alternation field and thermal demagnetisations as well as rock magnetic experiments. The baked clay with was formed from a loess sediment has preserved stable directions. Apart from one exception the mean characteristic remanent magnetization directions are concentrated around 900 AD on the early medieval part of the directional archaeomagnetic reference curve of Austria (Schnepp & Lanos, GJI, 2006). Using this curve archaeomagnetic dating with RenDate provides ages between 800 and 1100 AD which are in agreement with archaeological dating. In one case archaeomagnetic dating is even more precise. Together with the archaeological age estimates and stratigraphic information the new data have been included into the database of the Austrian curve. It has been recalculated using a new version of RenCurve. The new data confine the curve and its error band considerably in the time interval 800 to 1100 AD. The curve calibration process also provides a probability density distribution for each structure which allows for posterior dating. This refines temporal errors considerably. Usefulness of such an approach and archaeological implications will be discussed.

  7. Effect of changes in stimulus site on activation of the posterior parietal cortex.

    PubMed

    Yamashiro, Koya; Sato, Daisuke; Onishi, Hideaki; Sugawara, Kazuhiro; Nakazawa, Sho; Kameyama, Shigeki; Maruyama, Atsuo

    2015-03-01

    A previous functional magnetic resonance imaging study elucidated the specific activity of the inferior parietal lobe (IPL) during a two-point discrimination task compared with that during an intensity discrimination task Akatsuka et al. (Neuroimage 40: 852-858, 2008). If the posterior parietal cortex (PPC), including IPL, is responsible for detecting changes in stimulus sites, PPC activity depends on the level of change at stimulus sites. The aim of this study was to clarify whether a particular site exists that could detect changes in stimulus sites using the oddball paradigm. Somatosensory-evoked magnetic fields were recorded in 10 right-handed subjects. Three oddball conditions were performed by all subjects, with the probability of deviant and standard stimuli being 20 and 80 %, respectively, under all three conditions. Deviant stimuli were always presented to the second digit of the hand and standard stimuli were presented to the first (small deviance: SD) and fifth digits (medium deviance: MD) of the hand and the first digit of the toe (large deviance: LD). Inter-stimulus intervals were set at 500 ms. A brain electrical source analysis showed that activities of areas 1 and 3b elicited by the deviant stimuli were not significantly different among the three conditions. In contrast, PPC activity was significantly greater for LD than for SD and MD. PPC activity tended to increase with greater deviance at stimulus sites, but activities of areas 1 and 3b did not differ. These findings suggest that PPC may have a functional role in automatic change detection systems with regard to deviance of stimulus sites. PMID:24878895

  8. Rapid Bayesian point source inversion using pattern recognition --- bridging the gap between regional scaling relations and accurate physical modelling

    NASA Astrophysics Data System (ADS)

    Valentine, A. P.; Kaeufl, P.; De Wit, R. W. L.; Trampert, J.

    2014-12-01

    Obtaining knowledge about source parameters in (near) real-time during or shortly after an earthquake is essential for mitigating damage and directing resources in the aftermath of the event. Therefore, a variety of real-time source-inversion algorithms have been developed over recent decades. This has been driven by the ever-growing availability of dense seismograph networks in many seismogenic areas of the world and the significant advances in real-time telemetry. By definition, these algorithms rely on short time-windows of sparse, local and regional observations, resulting in source estimates that are highly sensitive to observational errors, noise and missing data. In order to obtain estimates more rapidly, many algorithms are either entirely based on empirical scaling relations or make simplifying assumptions about the Earth's structure, which can in turn lead to biased results. It is therefore essential that realistic uncertainty bounds are estimated along with the parameters. A natural means of propagating probabilistic information on source parameters through the entire processing chain from first observations to potential end users and decision makers is provided by the Bayesian formalism.We present a novel method based on pattern recognition allowing us to incorporate highly accurate physical modelling into an uncertainty-aware real-time inversion algorithm. The algorithm is based on a pre-computed Green's functions database, containing a large set of source-receiver paths in a highly heterogeneous crustal model. Unlike similar methods, which often employ a grid search, we use a supervised learning algorithm to relate synthetic waveforms to point source parameters. This training procedure has to be performed only once and leads to a representation of the posterior probability density function p(m|d) --- the distribution of source parameters m given observations d --- which can be evaluated quickly for new data.Owing to the flexibility of the pattern-recognition based approach, the algorithm can be easily extended to be used with a wide variety of input data, ranging from seismic waveform- to geodetic data. We present a way to deal with noisy observations and missing input data and show how the algorithm could be incorporated into a local earthquake early warning system.

  9. The probability of iterated conditionals.

    PubMed

    van Wijnbergen-Huitink, Janneke; Elqayam, Shira; Over, David E

    2015-05-01

    Iterated conditionals of the form If p, then if q, r are an important topic in philosophical logic. In recent years, psychologists have gained much knowledge about how people understand simple conditionals, but there are virtually no published psychological studies of iterated conditionals. This paper presents experimental evidence from a study comparing the iterated form, If p, then if q, r with the "imported," noniterated form, If p and q, then r, using a probability evaluation task and a truth-table task, and taking into account qualitative individual differences. This allows us to critically contrast philosophical and psychological approaches that make diverging predictions regarding the interpretation of these forms. The results strongly support the probabilistic Adams conditional and the "new paradigm" that takes this conditional as a starting point. PMID:25238396

  10. Problems with Objective Probability for Conditionals What Bennett Means by Objective Probability

    E-print Network

    Fitelson, Branden

    Problems with Objective Probability for Conditionals What Bennett Means by Objective Probability before. Problem: Drastically underdetermined. Probability varies with P so P(A->C) isn't even a function Objective probability is any sort of probability which demands inter- subjective agreement. Bennett

  11. first hit probability 11/13/2007 1 First hit probability

    E-print Network

    Taylor, Peter

    first hit probability 11/13/2007 1 First hit probability For the spinner illustrated at the right angle. Thus the probability the pointer will hit A is 5/36 and the probability the pointer will hit B is 4/36. Here's the problem: Find the probability that the pointer will hit A before it hits B. That is

  12. The retinoic acid signaling pathway regulates anterior/posterior patterning in the nerve cord and pharynx of amphioxus, a chordate lacking neural crest

    NASA Technical Reports Server (NTRS)

    Escriva, Hector; Holland, Nicholas D.; Gronemeyer, Hinrich; Laudet, Vincent; Holland, Linda Z.

    2002-01-01

    Amphioxus, the closest living invertebrate relative of the vertebrates, has a notochord, segmental axial musculature, pharyngeal gill slits and dorsal hollow nerve cord, but lacks neural crest. In amphioxus, as in vertebrates, exogenous retinoic acid (RA) posteriorizes the embryo. The mouth and gill slits never form, AmphiPax1, which is normally downregulated where gill slits form, remains upregulated and AmphiHox1 expression shifts anteriorly in the nerve cord. To dissect the role of RA signaling in patterning chordate embryos, we have cloned the single retinoic acid receptor (AmphiRAR), retinoid X receptor (AmphiRXR) and an orphan receptor (AmphiTR2/4) from amphioxus. AmphiTR2/4 inhibits AmphiRAR-AmphiRXR-mediated transactivation in the presence of RA by competing for DR5 or IR7 retinoic acid response elements (RAREs). The 5' untranslated region of AmphiTR2/4 contains an IR7 element, suggesting possible auto- and RA-regulation. The patterns of AmphiTR2/4 and AmphiRAR expression during embryogenesis are largely complementary: AmphiTR2/4 is strongly expressed in the cerebral vesicle (homologous to the diencephalon plus anterior midbrain), while AmphiRAR expression is high in the equivalent of the hindbrain and spinal cord. Similarly, while AmphiTR2/4 is expressed most strongly in the anterior and posterior thirds of the endoderm, the highest AmphiRAR expression is in the middle third. Expression of AmphiRAR is upregulated by exogenous RA and completely downregulated by the RA antagonist BMS009. Moreover, BMS009 expands the pharynx posteriorly; the first three gill slit primordia are elongated and shifted posteriorly, but do not penetrate, and additional, non-penetrating gill slit primordia are induced. Thus, in an organism without neural crest, initiation and penetration of gill slits appear to be separate events mediated by distinct levels of RA signaling in the pharyngeal endoderm. Although these compounds have little effect on levels of AmphiTR2/4 expression, RA shifts pharyngeal expression of AmphiTR2/4 anteriorly, while BMS009 extends it posteriorly. Collectively, our results suggest a model for anteroposterior patterning of the amphioxus nerve cord and pharynx, which is probably applicable to vertebrates as well, in which a low anterior level of AmphiRAR (caused, at least in part, by competitive inhibition by AmphiTR2/4) is necessary for patterning the forebrain and formation of gill slits, the posterior extent of both being set by a sharp increase in the level of AmphiRAR. Supplemental data available on-line.

  13. Sensitivity Analysis and Assessment of Prior Model Probabilities in MLBMA with Application to Unsaturated Fractured Tuff

    SciTech Connect

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

    2005-12-24

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

  14. New-onset craniosynostosis after posterior vault distraction osteogenesis.

    PubMed

    Tahiri, Youssef; Paliga, James Thomas; Bartlett, Scott P; Taylor, Jesse A

    2015-01-01

    The aims of this study were to document the incidence of new-onset craniosynostosis (NOC) after posterior vault distraction osteogenesis (PVDO), to determine risk factors for the development of NOC, and to deduce the cranial ramifications of NOC. An institutional review board-approved retrospective review of all patients who underwent PVDO at the Children's Hospital of Philadelphia was performed. Demographics, perioperative data, as well as preoperative and postoperative three-dimensional computed tomographic scans were analyzed. Suture patency preoperatively and postoperatively was recorded.Thirty patients underwent PVDO for suspected increased intracranial pressure and/or severe turribrachicephaly from 2008 to 2013. Twenty-four patients had syndromic diagnoses. The average age at the time of PVDO was 2.03 years. Distraction distances ranged from 19 to 40 mm, with an average of 28.7 mm. Among the 19 patients who had patent lambdoid sutures before PVDO, new-onset lambdoid fusion was seen in 17 patients after PVDO (89.5%), whereas the suture remained open in 2 patients (10.5%). New-onset lambdoid fusion was not significantly associated with age at distraction (P = 0.28), sex (P = 0.47), length of distraction (P = 0.93), or diagnosis (P = 0.61). Similarly, new-onset sagittal synostosis was not associated with age at distraction (P = 0.06), sex (P = 0.64), length of distraction (P = 0.83), or diagnosis (P = 0.25). None of the patients who developed NOC had characteristic head shape changes such as mastoid bulges or scaphocephaly. New-onset lambdoid and sagittal synostoses occur frequently after PVDO. Although the diagnosis of NOC is obvious radiographically, the clinical importance of the diagnosis morphometrically, neurodevelopmentally, and in cranial growth has yet to be fully investigated. PMID:25469894

  15. Lateralized modulation of posterior alpha oscillations in children.

    PubMed

    Vollebregt, Madelon A; Zumer, Johanna M; Ter Huurne, Niels; Castricum, Jesminne; Buitelaar, Jan K; Jensen, Ole

    2015-12-01

    The evidence for a functionally inhibitory role of alpha oscillations is growing stronger, mostly derived from studies in healthy adults investigating spatial attention. It remains unexplored if the modulation of alpha band oscillations plays a similar functional role in typically developing children. The aim of this study was to characterize alpha modulations in children in relation to attentional performance. To this end, the posterior alpha activity (8-12Hz) in children between 7 and 10years old was measured using EEG while they performed a visuospatial covert attention task. We found that the alpha activity decreased in the hemisphere contralateral to the attended hemifield, whereas it relatively increased in the other hemisphere. In addition, we found that the degree of lateralized alpha modulation predicted performance on the attention task by negatively predicting the response time on invalid trials. Of note, children who were behaviorally less influenced by spatial cueing also were children with a clear lateralized alpha modulation pattern, with a significantly stronger alpha lateralization in the left hemisphere than children who were influenced more by spatial cueing. In addition, a bias to the right visual field such as that commonly observed in children, was significantly smaller or absent in the children influenced least by spatial cueing. Among all children, the magnitude of this visual field bias was positively related to the ability to modulate alpha activity. In conclusion, we have shown that the pattern of alpha oscillations modulated by attention is already present in 7-10year old typically developing children. Although a similar pattern is observed in adults, the consequences for behavior are different. The fact that alpha modulation is already present at this age opens up the possibility of using hemispheric alpha lateralization as a tool to study the physiological basis of attention deficits in clinical disorders such as ADHD. PMID:26119021

  16. Specialized Pathways from the Primate Amygdala to Posterior Orbitofrontal Cortex

    PubMed Central

    Timbie, Clare

    2014-01-01

    The primate amygdala sends dense projections to posterior orbitofrontal cortex (pOFC) in pathways that are critical for processing emotional content, but the synaptic mechanisms are not understood. We addressed this issue by investigating pathways in rhesus monkeys (Macaca mulatta) from the amygdala to pOFC at the level of the system and synapse. Terminations from the amygdala were denser and larger in pOFC compared with the anterior cingulate cortex, which is also strongly connected with the amygdala. Axons from the amygdala terminated most densely in the upper layers of pOFC through large terminals. Most of these terminals innervated spines of presumed excitatory neurons and many were frequently multisynaptic and perforated, suggesting high synaptic efficacy. These amygdalar synapses in pOFC exceeded in size and specialization even thalamocortical terminals from the prefrontal-related thalamic mediodorsal nucleus to the middle cortical layers, which are thought to be highly efficient drivers of cortical neurons. Pathway terminals in the upper layers impinge on the apical dendrites of neurons in other layers, suggesting that the robust amygdalar projections may also activate neurons in layer 5 that project back to the amygdala and beyond to autonomic structures. Among inhibitory neurons, the amygdalar pathway innervated preferentially the neurochemical classes of calbindin and calretinin neurons in the upper layers of pOFC, which are synaptically suited to suppress noise and enhance signals. These features provide a circuit mechanism for flexibly shifting focus and adjusting emotional drive in processes disrupted in psychiatric disorders, such as phobias and obsessive–compulsive disorder. PMID:24920616

  17. Hox Genes Promote Neuronal Subtype Diversification through Posterior Induction in Caenorhabditis elegans.

    PubMed

    Zheng, Chaogu; Diaz-Cuadros, Margarete; Chalfie, Martin

    2015-11-01

    Although Hox genes specify the differentiation of neuronal subtypes along the anterior-posterior axis, their mode of action is not entirely understood. Using two subtypes of the touch receptor neurons (TRNs) in C. elegans, we found that a "posterior induction" mechanism underlies the Hox control of terminal neuronal differentiation. The anterior subtype maintains a default TRN state, whereas the posterior subtype undergoes further morphological and transcriptional specification induced by the posterior Hox proteins, mainly EGL-5/Abd-B. Misexpression of the posterior Hox proteins transformed the anterior TRN subtype toward a posterior identity both morphologically and genetically. The specification of the posterior subtype requires EGL-5-induced repression of TALE cofactors, which antagonize EGL-5 functions, and the activation of rfip-1, a component of recycling endosomes, which mediates Hox activities by promoting subtype-specific neurite outgrowth. Finally, EGL-5 is required for subtype-specific circuit formation by acting in both the sensory neuron and downstream interneuron to promote functional connectivity. PMID:26539892

  18. Probability Surveys ISSN: 1549-5787

    E-print Network

    Grimmett, Geoffrey

    Probability Surveys Vol. () ISSN: 1549-5787 Erratum: Three theorems in discrete random geometry in the survey entitled `Three theorems in discrete random geometry', published in Probability Surveys 8 (2011

  19. Free probability and combinatorics Preliminary version

    E-print Network

    Anshelevich, Michael

    Free probability and combinatorics Preliminary version Michael Anshelevich c 2012 April 24, 2015 #12;Preface These notes were used in a topics course Free probability and combinatorics taught Free independence. 19 3.1 Independence. Free independence

  20. The Probability Distribution for a Biased Spinner

    ERIC Educational Resources Information Center

    Foster, Colin

    2012-01-01

    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.)

  1. Probability Out Of Determinism Michael Strevens

    E-print Network

    Strevens, Michael

    ). Such a theory is imputing probabilities to a more or less deterministic world, then, and the question naturally arises--how can a deterministic world nurture stochasticity? Deterministic probabilities are ascribed

  2. The biomechanics of the knee following injury and reconstruction of the posterior cruciate ligament c Louis DeFrate.

    E-print Network

    DeFrate, Louis E., 1977-

    2005-01-01

    Very little is known regarding the function of the posterior cruciate ligament in response to physiological loading conditions. A limited understanding of posterior cruciate ligament function might contribute to the poor ...

  3. A statistical method for assessing peptide identification confidence in accurate mass and time tag proteomics.

    PubMed

    Stanley, Jeffrey R; Adkins, Joshua N; Slysz, Gordon W; Monroe, Matthew E; Purvine, Samuel O; Karpievitch, Yuliya V; Anderson, Gordon A; Smith, Richard D; Dabney, Alan R

    2011-08-15

    Current algorithms for quantifying peptide identification confidence in the accurate mass and time (AMT) tag approach assume that the AMT tags themselves have been correctly identified. However, there is uncertainty in the identification of AMT tags, because this is based on matching LC-MS/MS fragmentation spectra to peptide sequences. In this paper, we incorporate confidence measures for the AMT tag identifications into the calculation of probabilities for correct matches to an AMT tag database, resulting in a more accurate overall measure of identification confidence for the AMT tag approach. The method is referenced as Statistical Tools for AMT Tag Confidence (STAC). STAC additionally provides a uniqueness probability (UP) to help distinguish between multiple matches to an AMT tag and a method to calculate an overall false discovery rate (FDR). STAC is freely available for download, as both a command line and a Windows graphical application. PMID:21692516

  4. Termination zones of functionally characterized spinothalamic tract neurons within the primate posterior thalamus.

    PubMed

    Davidson, Steve; Zhang, Xijing; Khasabov, Sergey G; Simone, Donald A; Giesler, Glenn J

    2008-10-01

    The primate posterior thalamus has been proposed to contribute to pain sensation, but its precise role is unclear. This is in part because spinothalamic tract (STT) neurons that project to the posterior thalamus have received little attention. In this study, antidromic mapping was used to identify individual STT neurons with axons that projected specifically to the posterior thalamus in Macaca fascicularis. Each axon was located by antidromic activation at low stimulus amplitudes (<30 microA) and was then surrounded distally by a grid of stimulating points in which 500-microA stimuli were unable to activate the axon antidromically, thereby indicating the termination zone. Several nuclei within the posterior thalamus were targets of STT neurons: the posterior nucleus, suprageniculate nucleus, magnocellular part of the medial geniculate nucleus, and limitans nucleus. STT neurons projecting to the ventral posterior inferior nucleus were also studied. Twenty-five posterior thalamus-projecting STT neurons recorded in lumbar spinal cord were characterized by their responses to mechanical, thermal, and chemical stimuli. Sixteen of 25 neurons were recorded in the marginal zone and the balance was located within the deep dorsal horn. Thirteen neurons were classified as wide dynamic range and 12 as high threshold. One-third of STT neurons projecting to posterior thalamus responded to noxious heat (50 degrees C). Two-thirds of those tested responded to cooling. Seventy-one percent responded to an intradermal injection of capsaicin. These data indicate that the primate STT transmits noxious and innocuous mechanical, thermal, and chemical information to multiple posterior thalamic nuclei. PMID:18701750

  5. A comparative study of central versus posterior approach for internal jugular hemodialysis catheter insertion

    PubMed Central

    Mathur, M.; D'Souza, A. V. L.; Prasad, D.; Garsa, R.; Bansal, N.; Jhorawat, R.; Sharma, S.; Beniwal, P.; Agrawal, D.; Malhotra, V.

    2015-01-01

    Internal jugular (IJ) catheter insertion for hemodialysis (HD) is an indispensable procedure in the management of patients with renal failure. The central approach is favored over posterior approach to insert IJ catheters. There are no studies comparing the outcomes between the two approaches. The aim of this study was to compare central approach with posterior approach for IJ HD catheter insertion and to analyze various outcomes like procedure-related complication rates, catheter insertion failure rates, interruptions during dialysis due to blood flow obstruction and catheter infection rates between the two methods among patients receiving HD. All patients requiring IJ HD catheter insertion during a 1-month period were randomly assigned to undergo catheter insertion via either conventional central approach or posterior approach. Patients were followed-up till the removal of the catheter. Among 104 patients included in the study, 54 were assigned to the central approach group and 50 to the posterior approach group. The central approach group had higher rate of procedure-related complications (14.81% vs. 6%, P = 0.04). Catheter insertion failure rates were marginally higher in posterior approach group (20% vs. 12.96%, P = 0.07). One or more instance of interruption during HD due to obstruction in blood flow was more common in posterior approach (46% vs. 9.25%, P < 0.01). Catheter infection rates were similar between the two groups; 16.66% (n = 9) in central group vs. 14% (n = 7) in posterior group. Posterior approach is a reasonable alternative to conventional central approach in IJ cannulation for HD catheter. It is, however, associated with a significantly high rate of interruption in HD blood flow and catheter insertion failure rates. The posterior approach can be used in patients with local exit site infection or in failed attempts to cannulate IJ vein via the conventional central approach.

  6. Single-stage posterior-only approach treating single-segment thoracic tubercular spondylitis

    PubMed Central

    Shen, Xiongjie; Liu, Hongzhe; Wang, Guoping; Liu, Xiangyang

    2015-01-01

    There are quite a few controversies on surgical management of single-segment thoracic spinal tuberculosis (STB) with neurological deficits. The present study was to compare single-stage posterior-only transpedicular debridement, interbody fusion and posterior instrumentation (posterior-only surgery) with a combined posterior-anterior surgical approach for treatment of single-segment thoracic STB with neurological deficits and to determinethe clinical feasibility and effectiveness of posterior-only surgical treatment. Sixty patients with single-segment thoracic STB with neurological deficits were treated with one of two surgical procedures in our center from January 2003 to January 2013. Thirty patients were treated with posterior-only surgery (Group A) andthirty were treated with combined posterior-anterior surgery (Group B). The American Spinal Injury Association (ASIA) score system to evaluate the neurological deficits, thevisual analogue scale (VAS) to assess the degree of pain, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to judge the activity of tuberculosis (TB), surgery duration, intraoperative blood loss, length of hospitalization, bonyfusion rates, and kyphosis correction of the two groups were compared. The average follow-up period was 36.5 ± 9.2 months for Group A and 34.6 ± 10.2 months for Group B. Under the ASIA score system, all patients improved with treatment. STB was completely cured and grafted bones were fused within 5-11 months in allpatients. There were no persistent or recurrent infections orobvious differences in radiological results between thegroups. The kyphosis deformity was significantly corrected after surgical management. The average operative duration, blood loss, length of hospital stay, and postoperative complication rateof Group A were lower than those of Group B. In conclusions, posterior-only surgery is feasible and effective, resulting in better clinical outcomes than combined posterior-anterior surgeries, especially in surgical time, blood loss, hospital stay, and complications. PMID:26617823

  7. Distribution of Posterior Corneal Astigmatism According to Axis Orientation of Anterior Corneal Astigmatism

    PubMed Central

    Miyake, Toshiyuki; Shimizu, Kimiya; Kamiya, Kazutaka

    2015-01-01

    Purpose To investigate the distribution of posterior corneal astigmatism in eyes with with-the-rule (WTR) and against-the-rule (ATR) anterior corneal astigmatism. Methods We retrospectively examined six hundred eight eyes of 608 healthy subjects (275 men and 333 women; mean age ± standard deviation, 55.3 ± 20.2 years). The magnitude and axis orientation of anterior and posterior corneal astigmatism were determined with a rotating Scheimpflug system (Pentacam HR, Oculus) when we divided the subjects into WTR and ATR anterior corneal astigmatism groups. Results The mean magnitudes of anterior and posterior corneal astigmatism were 1.14 ± 0.76 diopters (D), and 0.37 ± 0.19 D, respectively. We found a significant correlation between the magnitudes of anterior and posterior corneal astigmatism (Pearson correlation coefficient r = 0.4739, P<0.001). In the WTR anterior astigmatism group, we found ATR astigmatism of the posterior corneal surface in 402 eyes (96.6%). In the ATR anterior astigmatism group, we found ATR posterior corneal astigmatism in 82 eyes (73.9%). Especially in eyes with ATR anterior corneal astigmatism of 1 D or more and 1.5 D or more, ATR posterior corneal astigmatism was found in 28 eyes (59.6%) and 9 eyes (42.9%), respectively. Conclusions WTR anterior astigmatism and ATR posterior astigmatism were found in approximately 68% and 91% of eyes, respectively. The magnitude and the axis orientation of posterior corneal astigmatism were not constant, especially in eyes having high ATR anterior corneal astigmatism, as is often the case in patients who have undergone toric IOL implantation. PMID:25625283

  8. Estimating exceedance probabilities of extreme floods

    SciTech Connect

    Fontaine, T.A.; Potter, K.W.

    1994-09-01

    Estimates of the exceedance probabilities of extreme floods are needed for risk analysis of dams and nuclear facilities. A new approach using a joint probability distribution of extreme rainfalls and antecedent soil moisture conditions, along with a rainfall runoff model, provides estimates of probabilities for floods approaching the probable maximum flood. This approach is illustrated for a 570 km{sup 2} catchment in the upper midwestern U.S.

  9. Ultrasound imaging accurately identifies the intercostobrachial nerve

    PubMed Central

    Thallaj, Ahmed K.; Harbi, Mohammad K. Al; Alzahrani, Tariq A.; El-Tallawy, Salah N.; Alsaif, Abdulaziz A.; Alnajjar, Mohannad

    2015-01-01

    Objectives: To test the hypothesis that identification and blockade of the intercostobrachial nerve (ICBN) can be achieved under ultrasound (US) guidance using a small volume of local anesthetic. Methods: Twenty-eight adult male volunteers were examined at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia from November 2012 to September 2013. Intercostobrachial nerve blockade was performed using one ml of 2% lidocaine under US guidance. A sensory map of the blocked area was developed relative to the medial aspect of the humeral head. Results: The ICBN appears as a hyper-echoic structure. The nerve diameter was 2.3±0.28 mm, and the depth was 9±0.28 mm. The measurements of the sensory-blocked area relative to the medial aspect of the humeral head were as follows: 6.3±1.6 cm anteriorly; 6.2±2.9 cm posteriorly; 9.4±2.9 cm proximally; and 9.2±4.4 cm distally. Intercostobrachial nerve blockade using one ml of local anesthetic was successful in all cases. Conclusion: The present study described the sonographic anatomical details of the ICBN and its sensory distribution to successfully perform selective US-guided ICBN blockade. PMID:26446339

  10. An accurate registration technique for distorted images

    NASA Technical Reports Server (NTRS)

    Delapena, Michele; Shaw, Richard A.; Linde, Peter; Dravins, Dainis

    1990-01-01

    Accurate registration of International Ultraviolet Explorer (IUE) images is crucial because the variability of the geometrical distortions that are introduced by the SEC-Vidicon cameras ensures that raw science images are never perfectly aligned with the Intensity Transfer Functions (ITFs) (i.e., graded floodlamp exposures that are used to linearize and normalize the camera response). A technique for precisely registering IUE images which uses a cross correlation of the fixed pattern that exists in all raw IUE images is described.

  11. Probability in the Engineering and Informational Sciences

    E-print Network

    Oren, Shmuel S.

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

  12. MATH10141 2014/2015 Probability 1

    E-print Network

    Sidorov, Nikita

    - 20% This is archived information. Please visit http://www.maths.manchester.ac.uk for current course on probability distributions. Syllabus 1. Random experiments, sample space and events, the algebra of events events. Combinatorial probability. [4] 2. Conditional probability of an event. Multiplication rule

  13. Remarriage Probability After Widowhood: A Retrospective Method

    ERIC Educational Resources Information Center

    Cleveland, William P.; Gianturco, Daniel T.

    1976-01-01

    A technique was devised to estimate age specific remarriage probabilities for newly widowed persons utilizing North Carolina marriage certificates plus information from the 1970 U.S. Census. Remarriage probabilities are very high for persons widowed before age 35. Remarriage probabilities decrease faster for widows than widowers. Age specific…

  14. CSCI 688: Computational Probability Summer, 2011

    E-print Network

    Leemis, Larry

    computing can be used to solve intractable problems in probability and statistics. A research project chosenCSCI 688: Computational Probability Summer, 2011 MTWRF 10:10­11:40 Jones 302 Instructor: Larry-based probability and some exposure to statistics. Text: Drew, J.H., Evans, D.L., Glen, A.G., Leemis, L

  15. MATH 382 Spring 2014 Probability & Statistics

    E-print Network

    Borchers, Brian

    are some problems, methods and examples from probability? How will this class be conducted? EventsMATH 382 Spring 2014 Probability & Statistics Instructor: Dr. Anwar Hossain, Weir 238, Ext. 5135 E of this course is to help you become familiar with the techniques, procedures and concepts of probability

  16. A New Variant of Posterior Canal Benign Paroxysmal Positional Vertigo: A Nonampullary or Common Crus Canalolithiasis

    PubMed Central

    Yetiser, Sertac

    2015-01-01

    Clockwise or counterclockwise, rotational, upbeating nystagmus is seen in patients with posterior canal benign paroxysmal positional vertigo during left or right head-hanging test, respectively. Rotating of nystagmus in opposite direction to the ear tested or even reversal of initial positioning rotational nystagmus is not usual and has never been reported before. We propose a new variant of posterior canal benign paroxysmal positional vertigo due to unusual behavior and location of the otoliths inside the membranous labyrinth. Unexpected rotational direction may lead to confusion about the site. The examiner should be aware of this abnormal or atypical variant of posterior canal benign paroxysmal positional vertigo. PMID:26114003

  17. A New Variant of Posterior Canal Benign Paroxysmal Positional Vertigo: A Nonampullary or Common Crus Canalolithiasis.

    PubMed

    Yetiser, Sertac

    2015-01-01

    Clockwise or counterclockwise, rotational, upbeating nystagmus is seen in patients with posterior canal benign paroxysmal positional vertigo during left or right head-hanging test, respectively. Rotating of nystagmus in opposite direction to the ear tested or even reversal of initial positioning rotational nystagmus is not usual and has never been reported before. We propose a new variant of posterior canal benign paroxysmal positional vertigo due to unusual behavior and location of the otoliths inside the membranous labyrinth. Unexpected rotational direction may lead to confusion about the site. The examiner should be aware of this abnormal or atypical variant of posterior canal benign paroxysmal positional vertigo. PMID:26114003

  18. High Frequency QRS ECG Accurately Detects Cardiomyopathy

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  19. Transtibial Tunnel Placement in Posterior Cruciate Ligament Reconstruction

    PubMed Central

    Tompkins, Marc; Keller, Thomas C.; Milewski, Matthew D.; Gaskin, Cree M.; Brockmeier, Stephen F.; Hart, Joseph M.; Miller, Mark D.

    2014-01-01

    Background: It is common to place the posterior cruciate ligament (PCL) tibial tunnel with a transtibial technique using a guide that attempts to place the center of the tunnel 1 to 1.5 cm distal to the tibiofemoral joint. It is unknown how well this technique will re-create the native tibial footprint of the PCL. Purpose: To evaluate the accuracy of tibial tunnel placement using a transtibial technique. Study Design: Controlled laboratory study. Methods: Ten cadaveric knees from 10 donors underwent arthroscopic transtibial drilling of the tibial tunnel with use of a posteromedial portal for visualization. The transtibial guide was rested flush against the tibial spines to allow for the guide to be as distal as possible, which was between 1 and 1.5 cm distal to the tibiofemoral joint line. Using this technique, an attempt was made to place the tibial tunnels as close to the center of the PCL footprint as possible. All knees underwent computed tomography both pre- and postoperatively with a previously reported technique optimized for ligament evaluation. This allowed comparison of the anatomic PCL tibial footprint to the tibial tunnel aperture. The percentage of tunnel aperture contained within the native footprint as well as the distance from the center of the tunnel aperture to the center of the footprint was measured. Results: The percentage of tunnel aperture contained within the native footprint was 45.9% ± 23.1%. The distance from the center of the tibial tunnel aperture to the center of the tibial PCL footprint was 6.4 ± 2.3 mm. The tunnels were almost always (9/10) distal (or inferior) to the native footprint and either slightly lateral (5/10) or centered (5/10) in a medial to lateral direction. Conclusion: This study demonstrates that using the transtibial drilling technique in the tibia for PCL reconstruction places approximately half of the tibial tunnel aperture within the tibial footprint. Generally, the tunnel is distal to the footprint. Clinical Relevance: Consideration should be given to the fact that, using this transtibial technique, the tibial tunnel aperture is generally not placed in the center of the footprint. This may not be a negative issue, however, since there are other potential advantages from distal tunnel placement. PMID:26535303

  20. Always Good Turing: asymptotically optimal probability estimation.

    PubMed

    Orlitsky, Alon; Santhanam, Narayana P; Zhang, Junan

    2003-10-17

    While deciphering the Enigma code, Good and Turing derived an unintuitive, yet effective, formula for estimating a probability distribution from a sample of data. We define the attenuation of a probability estimator as the largest possible ratio between the per-symbol probability assigned to an arbitrarily long sequence by any distribution, and the corresponding probability assigned by the estimator. We show that some common estimators have infinite attenuation and that the attenuation of the Good-Turing estimator is low, yet greater than 1. We then derive an estimator whose attenuation is 1; that is, asymptotically it does not underestimate the probability of any sequence. PMID:14564004

  1. Estimating Model Probabilities using Thermodynamic Markov Chain Monte Carlo Methods

    NASA Astrophysics Data System (ADS)

    Ye, M.; Liu, P.; Beerli, P.; Lu, D.; Hill, M. C.

    2014-12-01

    Markov chain Monte Carlo (MCMC) methods are widely used to evaluate model probability for quantifying model uncertainty. In a general procedure, MCMC simulations are first conducted for each individual model, and MCMC parameter samples are then used to approximate marginal likelihood of the model by calculating the geometric mean of the joint likelihood of the model and its parameters. It has been found the method of evaluating geometric mean suffers from the numerical problem of low convergence rate. A simple test case shows that even millions of MCMC samples are insufficient to yield accurate estimation of the marginal likelihood. To resolve this problem, a thermodynamic method is used to have multiple MCMC runs with different values of a heating coefficient between zero and one. When the heating coefficient is zero, the MCMC run is equivalent to a random walk MC in the prior parameter space; when the heating coefficient is one, the MCMC run is the conventional one. For a simple case with analytical form of the marginal likelihood, the thermodynamic method yields more accurate estimate than the method of using geometric mean. This is also demonstrated for a case of groundwater modeling with consideration of four alternative models postulated based on different conceptualization of a confining layer. This groundwater example shows that model probabilities estimated using the thermodynamic method are more reasonable than those obtained using the geometric method. The thermodynamic method is general, and can be used for a wide range of environmental problem for model uncertainty quantification.

  2. Differential behavioral reinforcement effects of dopamine receptor agonists in the rat with bilateral lesion of the posterior ventral tegmental area.

    PubMed

    Ouachikh, Omar; Dieb, Wisam; Durif, Franck; Hafidi, Aziz

    2013-09-01

    Dopamine dysregulation syndrome in Parkinson's disease has been attributed to dopamine replacement therapies and/or a lesion of the dopaminergic system. The dopaminergic neuronal loss targets the substantia nigra and the ventral tegmental area (VTA). We hypothesize that dopamine replacement therapy is responsible for the potential reinforcement effect in Parkinson's disease by acting on the neuronal reward circuitry. Therefore this study was designed to explore the potential motivational effect of dopamine replacement therapy in bilateral VTA-lesioned animals. The posterior (p)VTA, which project to the nucleus accumbens (NAc) constitutes the major dopamine neuronal circuitry implicated in addictive disorders. Using the conditioned place preference (CPP) behavioral paradigm, we investigated the motivational effects of dopamine receptor agonists, and cocaine in rat with a 6-OHDA bilateral lesion of the pVTA. Amongst the dopamine receptor agonists used in this study only the D2R and D3R agonists (bromocriptine, PD128907 and pramipexole), induced a significant CPP in pVTA-lesioned animals. Dopamine receptor agonists did not induce behavioral sensitization in sham animals. Moreover, confocal D2R immunostaining analysis showed a significant increase in the number of D2R per cell body in the NAc shell of pVTA lesioned rats compared to sham. This result correlated, for the first time, the dopamine receptor agonists effect with DR2 overexpression in the NAc shell of pVTA-lesioned rats. In addition, cocaine, which is known to increase dopamine release, induced behavioral sensitization in sham group but not in dopamine deprived group. Thus, the later result highlighted the importance of pVTA-NAc dopaminergic pathway in positive reinforcements. Altogether these data suggested that the implication of the dopamine replacement therapy in the appearance of dopamine dysregulation syndrome in Parkinson's disease is probably due to both neuronal degeneration in the posterior VTA and dopamine receptor sensitization in the dopamine depleted NAc. PMID:23727149

  3. Long term results of primary posterior chamber intraocular lens implantation for congenital cataract in the first year of life

    PubMed Central

    Gouws, P; Hussin, H M; Markham, R H C

    2006-01-01

    Aim To document the long term outcome of congenital cataract surgery with primary posterior chamber (PC) lens implantation in the first year of life. Method A retrospective review of congenital cataract surgery in the first year of life with PC lens implantation in 18 infants, eight with unilateral and 10 with bilateral cataract. The average age at surgery was 15?weeks (range 3–44?weeks). The mean follow up was 95?months (range 60–139?months). Results The best outcomes were in the bilateral group where 50% of eyes achieved 6/18 or better, with a best acuity of 6/9. Acuities were poor in the unilateral group where only 38% achieved 6/60 or better, with a best acuity of 6/24. There was a mean refractive shift between first refraction after surgery and refraction at 36?months after surgery of ?3.44?dioptres with a very wide range (+2.00 to ?15.50). There was a significantly greater myopic shift in the unilateral cases. Many eyes in both groups continued to show an increasing myopic shift between 36?months after surgery and their final recorded refraction. The main complications were amblyopia, especially in unilateral cataracts, and posterior capsular opacification. Amblyopia was most probably related to a combination of early onset of dense cataract in this young age group, late presentation for initial surgery, delay in capsulotomies, and imperfect compliance with a rigorous occlusion regime. Conclusion Intraocular lens implantation in infants less than 1?year of age is generally a safe procedure. The spread of final refractive error was very wide. Final refraction in the unilateral group was significantly more myopic than the bilateral group. Final acuities were often disappointing especially in the unilateral group. PMID:16597661

  4. Bell as the Copernicus of Probability

    E-print Network

    Andrei Khrennikov

    2015-01-10

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

  5. Accurate, Fully-Automated NMR Spectral Profiling for Metabolomics

    PubMed Central

    Ravanbakhsh, Siamak; Liu, Philip; Bjordahl, Trent C.; Mandal, Rupasri; Grant, Jason R.; Wilson, Michael; Eisner, Roman; Sinelnikov, Igor; Hu, Xiaoyu; Luchinat, Claudio; Greiner, Russell; Wishart, David S.

    2015-01-01

    Many diseases cause significant changes to the concentrations of small molecules (a.k.a. metabolites) that appear in a person’s biofluids, which means such diseases can often be readily detected from a person’s “metabolic profile"—i.e., the list of concentrations of those metabolites. This information can be extracted from a biofluids Nuclear Magnetic Resonance (NMR) spectrum. However, due to its complexity, NMR spectral profiling has remained manual, resulting in slow, expensive and error-prone procedures that have hindered clinical and industrial adoption of metabolomics via NMR. This paper presents a system, BAYESIL, which can quickly, accurately, and autonomously produce a person’s metabolic profile. Given a 1D 1H NMR spectrum of a complex biofluid (specifically serum or cerebrospinal fluid), BAYESIL can automatically determine the metabolic profile. This requires first performing several spectral processing steps, then matching the resulting spectrum against a reference compound library, which contains the “signatures” of each relevant metabolite. BAYESIL views spectral matching as an inference problem within a probabilistic graphical model that rapidly approximates the most probable metabolic profile. Our extensive studies on a diverse set of complex mixtures including real biological samples (serum and CSF), defined mixtures and realistic computer generated spectra; involving > 50 compounds, show that BAYESIL can autonomously find the concentration of NMR-detectable metabolites accurately (~ 90% correct identification and ~ 10% quantification error), in less than 5 minutes on a single CPU. These results demonstrate that BAYESIL is the first fully-automatic publicly-accessible system that provides quantitative NMR spectral profiling effectively—with an accuracy on these biofluids that meets or exceeds the performance of trained experts. We anticipate this tool will usher in high-throughput metabolomics and enable a wealth of new applications of NMR in clinical settings. BAYESIL is accessible at http://www.bayesil.ca. PMID:26017271

  6. Does restriction of glenohumeral horizontal adduction reflect posterior capsule thickening of the throwing shoulder?

    PubMed

    Ishigaki, Tomonobu; Ishida, Tomoya; Samukawa, Mina; Saito, Hiroshi; Ezawa, Yuya; Hirokawa, Motoki; Kato, Takumi; Sugawara, Makoto; Tohyama, Harukazu; Yamanaka, Masanori

    2015-05-01

    [Purpose] Glenohumeral posterior capsule tightness possibly relates to posterior capsule thickness (PCT). The purpose of the current study was to analyze the relationships between PCT and glenohumeral range of motion (ROM) in horizontal adduction (HAdd) and internal rotation (IR). [Subjects and Methods] This study recruited 39 healthy collegiate baseball players. We measured PCT by using ultrasonography and ROM of the glenohumeral joint of the throwing shoulder by using a digital inclinometer. Pearson's correlation coefficients were calculated between PCT and HAdd or IR ROM. [Results] There was no correlation between PCT and HAdd ROM, but PCT was significantly correlated with IR ROM. [Conclusion] This result indicates that posterior shoulder capsule tightness only relates to IR ROM, and that restricted HAdd ROM might reflect tightness of other tissue, such as the posterior deltoid. PMID:26157205

  7. Arthroscopic Distal Tibial Allograft Augmentation for Posterior Shoulder Instability With Glenoid Bone Loss

    PubMed Central

    Gupta, Anil K.; Chalmers, Peter N.; Klosterman, Emma; Harris, Joshua D.; Provencher, Matthew T.; Romeo, Anthony A.

    2013-01-01

    Glenoid bone loss is commonly associated with recurrent shoulder instability. Failure to recognize and appropriately address it can lead to poor outcomes. Numerous studies have found anterior-inferior glenoid bone loss in the setting of recurrent anterior instability. Though much less common, posterior shoulder instability can be seen in the setting of acute trauma, epilepsy, electrocution, and alcoholism. Heightened awareness has led to recognition in collision athletes as well. Posterior glenoid bone loss must be addressed in a similar fashion to anterior glenoid bone loss to prevent recurrent instability. Open bone augmentation procedures have been described with successful results. In this technical note, we describe an arthroscopic technique using fresh distal tibial allograft for posterior glenoid augmentation. In addition, a current review regarding the diagnosis and management of recurrent posterior shoulder instability is provided. PMID:24400190

  8. Microsurgical decompression of tumor of a rare posterior third ventricular pathology.

    PubMed

    Nanda, Anil; Konar, Subhas; Kalakoti, Piyush; Maiti, Tanmoy

    2016-01-01

    Of the posterior third ventricular tumors, a papillary tumor of the pineal gland is a rare entity that originates from specialized ependymoma of the subcommissural organ. In this video narration, we present a case of a 33-year-old male with headaches and recent cognitive decline due to a posterior third ventricular lesion. The patient underwent a posterior interhemispheric approach, and a gross-total decompression was achieved with no signs of recurrence in a 2-year follow-up period. With this case we highlight the microsurgical technique employed for decompressing tumors of the posterior third ventricular region with preservation of eloquent structures and draining veins. The video can be found here: https://youtu.be/o0WbyOqmtX0 . PMID:26722689

  9. Pediatric posterior cerebral artery stroke as a presentation of atlantoaxial dislocation.

    PubMed

    Nandish, H S; Borkar, Sachin A; Kale, Shashank S; Sharma, Bhawani S; Mahapatra, A K

    2015-01-01

    We report an uncommon case of posterior circulation stroke in a young patient due to occlusion of posterior cerebral artery with reducible atlantoaxial dislocation (AAD). Plain dynamic radiography showed reducible AAD and intra-arterial digital subtraction angiography demonstrated occlusion of left posterior cerebral artery. Patient underwent stabilization of craniovertebral junction by occipito cervical fixation using occipit-C2/C3 lateral mass screws and rod fixation and has since experienced no recurrent symptoms. Vertebrobasilar insufficiency is a known entity in a patient with reducible AAD; however, isolated involvement of posterior cerebral artery is very rare. So this condition should be kept in mind, and necessary interventions must be undertaken at the earliest to avoid further irreversible brain damage. PMID:26167221

  10. Pediatric posterior cerebral artery stroke as a presentation of atlantoaxial dislocation

    PubMed Central

    Nandish, H. S.; Borkar, Sachin A.; Kale, Shashank S.; Sharma, Bhawani S.; Mahapatra, A. K.

    2015-01-01

    We report an uncommon case of posterior circulation stroke in a young patient due to occlusion of posterior cerebral artery with reducible atlantoaxial dislocation (AAD). Plain dynamic radiography showed reducible AAD and intra-arterial digital subtraction angiography demonstrated occlusion of left posterior cerebral artery. Patient underwent stabilization of craniovertebral junction by occipito cervical fixation using occipit-C2/C3 lateral mass screws and rod fixation and has since experienced no recurrent symptoms. Vertebrobasilar insufficiency is a known entity in a patient with reducible AAD; however, isolated involvement of posterior cerebral artery is very rare. So this condition should be kept in mind, and necessary interventions must be undertaken at the earliest to avoid further irreversible brain damage. PMID:26167221

  11. Multimodal integration for the representation of space in the posterior parietal cortex

    E-print Network

    Multimodal integration for the representation of space in the posterior parietal cortex RICHARD A¡erent modalities to form a uni¢ed, multimodal impression of space. How this is accomplished has not been

  12. What about the “Self” is Processed in the Posterior Cingulate Cortex?

    E-print Network

    Brewer, Judson A.

    In the past decade, neuroimaging research has begun to identify key brain regions involved in self-referential processing, most consistently midline structures such as the posterior cingulate cortex (PCC). The majority of ...

  13. Treatment of unilateral posterior crossbite with facial asymmetry in a female patient with transverse discrepancy.

    PubMed

    Jung, Seok-Ki; Kim, Tae-Woo

    2015-07-01

    A unilateral posterior crossbite with facial asymmetry is difficult to correct with orthodontic treatment alone. This case report describes the orthodontic treatment and additional plasty without orthognathic surgery for a 19-year-old woman with a transverse discrepancy. The posterior crossbite was resolved by expansion of the narrow maxillary arch and space closure in the mandibular arch. This accelerated the correction of the functional shift of the mandible. After resolution of the unilateral posterior crossbite, the problems of the anteroposterior molar relationship were treated using orthodontic mini-implants. Mandibular angle reduction plasty was performed for the asymmetric mandibular border to improve the facial appearance. After treatment, the patient had a more symmetrical facial appearance, normal overjet and overbite, and midline coincidence. The treatment results remained stable 1 year after treatment. This case report demonstrates that a minimally invasive treatment can successfully correct a unilateral posterior crossbite with a transverse discrepancy. PMID:26124038

  14. Posterior fossa giant tumefactive perivascular spaces: 8-year follow-up in an adolescent

    PubMed Central

    Branch, Byron C.; Tantiwongkosi, Bundhit; Altmeyer, Wilson; Bartanusz, Viktor

    2015-01-01

    Background: Cystic masses in the posterior fossa are ominous appearing lesions with broad differential diagnosis. Giant tumefactive perivascular spaces (GTPS) are rarely occurring pathological findings in the posterior fossa with unclear etiology and ill-defined long-term prognosis. Case Description: We present a case of a 15-year-old male diagnosed with posterior fossa GTPS. The patient remained asymptomatic during the 8-year follow-up after diagnosis with the serial magnetic resonance imaging (MRI) showing no change in the size and morphology of the lesion. Conclusion: This case supports prior literature on supratentorial GTPS suggesting that the natural history of GTPS is mostly benign. Identification of GTPS in the posterior fossa could prevent the patient from unnecessary surgery or other aggressive treatment modalities. PMID:25657855

  15. Double transosseous pull out suture technique for transection of posterior horn of medial meniscus.

    PubMed

    Ahn, Jin Hwan; Wang, Joon Ho; Lim, Hong Chul; Bae, Ji Hoon; Park, Joon Soo; Yoo, Jae Chul; Shyam, Ashok Kumar

    2009-03-01

    Transection injury (complete radial tear, root tear) in the posterior horn of medial meniscus will lead to loss of hoop strain, extrusion of the meniscus and early degenerative changes. The posterior horn of medial meniscus is amenable to repair due to its good blood supply and repair is the procedure of choice for these injuries. In cases of transection of the medial meniscus posterior horn, the meniscus can be repaired by a pull out suture technique using trans-septal portal. The single transosseous pull out suturing technique is a point fixation technique with limited contact area having low and inhomogeneous contact pressure. This article describes a double transosseous pull out suture technique using trans-septal portal for the repair of transection of posterior horn of medial meniscus. Use of double transosseous technique provides more secure fixation, more homogeneous and wider contact pressure area between meniscus and the bone, improving the healing potential of the repair. PMID:18542975

  16. Posterior composite restoration update: focus on factors influencing form and function

    E-print Network

    Bohaty, Brenda S.; Ye, Qiang; Misra, Anil; Sene, Fabio; Spencer, Paulette

    2013-05-15

    Restoring posterior teeth with resin-based composite materials continues to gain popularity among clinicians, and the demand for such aesthetic restorations is increasing. Indeed, the most common aesthetic alternative to dental amalgam is resin...

  17. Periprosthetic fractures of the acetabulum during cup insertion: posterior column stability is crucial.

    PubMed

    Laflamme, G-Yves; Belzile, Etienne L; Fernandes, Julio C; Vendittoli, Pascal A; Hébert-Davies, Jonah

    2015-02-01

    Periprosthetic hip fractures around acetabular components are rare with little information available to guide surgical management of these complex injuries. A retrospective review of intraoperative isolated acetabular periprosthetic fractures from three tertiary surgical units was done. A total of 32 patients were identified with 9 initially missed. Acetabular components were stable (type 1) in 11 patients with no failures; unstable (type 2) in 12 patients and treated with supplemental fixation. Non-union and displacement were correlated with absent posterior column plating. Missed fractures (type 3) had the highest reoperation rate. Anterior patterns all healed, whereas fractures with posterior column instability had a 67% failure rate. Periprosthetic acetabular fracture can heal successfully with posterior column stability. Plating is mandatory for large posterior wall fragments to achieve osteointegration. PMID:25307882

  18. Drug delivery to the posterior segment of the eye for pharmacologic therapy

    PubMed Central

    Shah, Shalin S; Denham, Lori Vidal; Elison, Jasmine R; Bhattacharjee, Partha S; Clement, Christian; Huq, Tashfin; Hill, James M

    2010-01-01

    Treatment of diseases of the posterior segment of the eye, such as age-related macular degeneration, cytomegalovirus retinitis, diabetic retinopathy, posterior uveitis and retinitis pigmentosa, requires novel drug delivery systems that can overcome the many barriers for efficacious delivery of therapeutic drug concentrations. This challenge has prompted the development of biodegradable and nonbiodegradable sustained-release systems for injection or transplantation into the vitreous as well as drug-loaded nanoparticles, microspheres and liposomes. These drug delivery systems utilize topical, systemic, subconjunctival, intravitreal, transscleral and iontophoretic routes of administration. The focus of research has been the development of methods that will increase the efficacy of spatiotemporal drug application, resulting in more successful therapy for patients with posterior segment diseases. This article summarizes recent advances in the research and development of drug delivery methods of the posterior chamber of the eye, with an emphasis on the use of implantable devices as well as micro- and nanoparticles. PMID:20305803

  19. Posterior ankle impingement in athletes: Pathogenesis, imaging features and differential diagnoses.

    PubMed

    Hayashi, Daichi; Roemer, Frank W; D'Hooghe, Pieter; Guermazi, Ali

    2015-11-01

    Posterior ankle impingement is a clinical diagnosis which can be seen following a traumatic hyper-plantar flexion event and may lead to painful symptoms in athletes such as female dancers ('en pointe'), football players, javelin throwers and gymnasts. Symptoms of posterior ankle impingement are due to failure to accommodate the reduced interval between the posterosuperior aspect of the talus and tibial plafond during plantar flexion, and can be due to osseous or soft tissue lesions. There are multiple causes of posterior ankle impingement. Most commonly, the structural correlates of impingement relate to post-traumatic synovitis and intra-articular fibrous bands-scar tissue, capsular scarring, or bony prominences. The aims of this pictorial review article is to describe different types of posterior ankle impingement due to traumatic and non-traumatic osseous and soft tissue pathology in athletes, to describe diagnostic imaging strategies of these pathologies, and illustrate their imaging features, including relevant differential diagnoses. PMID:26239710

  20. THE BLACK HOLE FORMATION PROBABILITY

    SciTech Connect

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

    2015-02-01

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

  1. Integrated statistical modelling of spatial landslide probability

    NASA Astrophysics Data System (ADS)

    Mergili, M.; Chu, H.-J.

    2015-09-01

    Statistical methods are commonly employed to estimate spatial probabilities of landslide release at the catchment or regional scale. Travel distances and impact areas are often computed by means of conceptual mass point models. The present work introduces a fully automated procedure extending and combining both concepts to compute an integrated spatial landslide probability: (i) the landslide inventory is subset into release and deposition zones. (ii) We employ a simple statistical approach to estimate the pixel-based landslide release probability. (iii) We use the cumulative probability density function of the angle of reach of the observed landslide pixels to assign an impact probability to each pixel. (iv) We introduce the zonal probability i.e. the spatial probability that at least one landslide pixel occurs within a zone of defined size. We quantify this relationship by a set of empirical curves. (v) The integrated spatial landslide probability is defined as the maximum of the release probability and the product of the impact probability and the zonal release probability relevant for each pixel. We demonstrate the approach with a 637 km2 study area in southern Taiwan, using an inventory of 1399 landslides triggered by the typhoon Morakot in 2009. We observe that (i) the average integrated spatial landslide probability over the entire study area corresponds reasonably well to the fraction of the observed landside area; (ii) the model performs moderately well in predicting the observed spatial landslide distribution; (iii) the size of the release zone (or any other zone of spatial aggregation) influences the integrated spatial landslide probability to a much higher degree than the pixel-based release probability; (iv) removing the largest landslides from the analysis leads to an enhanced model performance.

  2. Precise measurements of the absolute ?-ray emission probabilities of (223)Ra and decay progeny in equilibrium.

    PubMed

    Collins, S M; Pearce, A K; Regan, P H; Keightley, J D

    2015-08-01

    Precise measurements of the absolute ?-ray emission probabilities have been made of radiochemically pure solutions of (223)Ra in equilibrium with its decay progeny, which had been previously standardised by 4?(liquid scintillation)-? digital coincidence counting techniques. Two high-purity germanium ?-ray spectrometers were used which had been accurately calibrated using a suite of primary and secondary radioactive standards. Comparison of the activity concentration determined by the primary technique against ?-ray spectrometry measurements using the nuclear data evaluations of the Decay Data Evaluation Project exhibited a range of ~18% in the most intense ?-ray emissions (>1% probability) of the (223)Ra decay series. Absolute ?-ray emission probabilities and standard uncertainties have been determined for the decay of (223)Ra, (219)Rn, (215)Po, (211)Pb, (211)Bi and (207)Tl in equilibrium. The standard uncertainties of the measured ?-ray emission probabilities quoted in this work show a significant improvement over previously reported ?-ray emission probabilities. Correlation coefficients for pairs of the measured ?-ray emission probabilities from the decays of the radionuclides (223)Ra, (219)Rn and (211)Pb have been determined and are presented. The ?-transition probabilities of the (223)Ra have been deduced from P(?+ce) balance using the ?-ray emission probabilities determined in this work with some agreement observed with the published experimental values of the ?-emission probabilities. PMID:25933406

  3. Accurate upwind methods for the Euler equations

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1993-01-01

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

  4. Pediatric posterior reversible encephalopathy syndrome presenting with isolated cerebellar edema and obstructive hydrocephalus.

    PubMed

    Ettinger, Nicholas; Pearson, Matthew; Lamb, Fred S; Wellons, John C

    2014-10-01

    In this report, the authors describe the case of a teenage boy who presented with hypertensive emergency, posterior reversible encephalopathy syndrome, and hydrocephalus due to fourth ventricle outlet obstruction. Posterior reversible encephalopathy syndrome is a well-characterized but uncommon syndrome in children that is generally triggered by severe hypertension. The unusual clinical picture of this patient, who had isolated cerebellar edema leading to obstructive hydrocephalus, has been rarely described in children. PMID:25062302

  5. Management for the anterior combined with posterior urethral stricture: a 9-year single centre experience

    PubMed Central

    Deng, Tuo; Liao, Banghua; Luo, Deyi; Liu, Bing; Wang, Kunjie; Liu, Jiaming; Jin, Tao

    2015-01-01

    Objective: Therapy for anterior combined with posterior urethral stricture is difficult and controversial. This study aims to introduce a standard process for managing anterior combined with posterior urethral stricture. Patients and methods: 19 patients with anterior combined with posterior urethral stricture were treated following our standard process. Average (range) age was 52 (21-72) years old. In this standard process, anterior urethral stricture should be treated first. Endoscopic surgery is applied for anterior urethra stricture as a priority as long as obliteration does not occur, and operation for posterior urethral stricture can be conducted in the same stage. Otherwise, an open reconstructive urethroplasty for anterior urethral is needed; while in this condition, the unobliterated posterior urethra can also be treated with endoscopic surgery in the same stage; however, if posterior urethra obliteration exists, then open reconstructive urethroplasty for posterior urethral stricture should be applied 2-3 months later. Results: The median (range) follow-up time was 25.8 (3-56) months. All 19 patients were normal in urethrography after 1 month of the surgery. 4 patients (21.1%) recurred urethral stricture during follow-up, and the locations of recurred stricture were bulbomembranous urethra (2 cases), bulbar urethra (1 case) and bladder neck (1 case). 3 of them restored to health through urethral dilation, yet 1 underwent a second operation. 2 patients (10.5%) complaint of dripping urination. No one had painful erection, stress urinary incontinence or other complications. Conclusions: The management for anterior combined with posterior urethral stricture following our standard process is effective and safe. PMID:26064293

  6. Two Unusual Aspects of Posterior Reversible Encephalopathy Syndrome Mimicking Primary and Secondary Brain Tumor Lesions

    PubMed Central

    Tchaou, Mazamaesso; Modruz, Nicoleta; Agoda-Koussema, Lama K.; Michelot, Anthony; Naffa, Samer; Jeudy, Véronique; Kaczmarek, Raymond

    2015-01-01

    The posterior reversible encephalopathy syndrome (PRES) is a rare clinical-radiological entity well described with typical clinical and radiological manifestations. Atypical presentation, especially in imaging, exists. The authors report here two cases of posterior reversible encephalopathy in which imaging aspects were atypical, mimicking, in the first case, hemorrhagic cerebral metastasis of cholangiocarcinoma and, in the second case, a brain tumor. The diagnosis has been retrospectively rectified due to clinical and radiological outcome. PMID:26587304

  7. Making the "inoperable" tumors "operable": Harvey Cushing's contributions to the surgery of posterior fossa tumors.

    PubMed

    Malekpour, Mahdi; Cohen-Gadol, Aaron A

    2014-04-01

    Harvey Cushing played a pivotal role in establishing neurosurgery as a distinct surgical discipline. One of his most important contributions was defining the surgical removal of posterior fossa tumors. Compulsive preoperative evaluation followed by meticulous surgical technique as well as incorporation of maneuvers such as ventricular puncture and electrocautery further advanced resection of tumors in this region. Herein, the authors review Cushing's contributions to posterior fossa surgery. PMID:24684327

  8. The first accurate description of an aurora

    NASA Astrophysics Data System (ADS)

    Schröder, Wilfried

    2006-12-01

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

  9. Accurate multiplication with noisy spiking neurons

    NASA Astrophysics Data System (ADS)

    Nezis, Panagiotis; van Rossum, Mark C. W.

    2011-06-01

    Multiplication is an operation which is fundamental in mathematics, but it is also relevant for many sensory computations in the nervous system. Nevertheless, despite a number of suggestions in the literature, it is not known how multiplication is implemented in neural circuitry. We propose a simple feedforward circuit that combines a rate model of neural activity and a realistic neural input-output relation to accurately and efficiently implement multiplication of two rate-coded quantities. By simulating a network of integrate and fire neurons, we demonstrate the functional efficiency of the circuit. Finally we discuss how the model can be tested experimentally.

  10. Updating Probabilities with Data and Moments

    E-print Network

    Giffin, Adom

    2007-01-01

    We use the method of Maximum (relative) Entropy to process information in the form of observed data and moment constraints. The generic "canonical" form of the posterior distribution for the problem of simultaneous updating with data and moments is obtained. We discuss the general problem of non-commuting constraints, when they should be processed sequentially and when simultaneously. As an illustration, the multinomial example of die tosses is solved in detail for two superficially similar but actually very different problems.

  11. Cannulation needle-induced anterior wall tenting of internal jugular vein causing posterior wall penetration.

    PubMed

    Yoshida, Hitoshi; Yaguchi, Shinya; Itaya, Hiroyuki; Ito, Kazuo; Hatanaka, Ryo; Nakai, Kishiko; Hirota, Kazuyoshi

    2015-06-01

    Unintentional posterior venous wall penetration during internal jugular vein (IJV) cannulation may cause critical arterial injuries in spite of ultrasound guidance. We aimed to evaluate whether small venous diameter and anterior venous wall tenting by a needle would be associated with posterior venous wall penetration, and to seek factors related to the venous wall tenting. We conducted a retrospective review in patients who underwent IJV cannulation. Using an ultrasound view obtained when puncturing, venous diameter, venous wall thickness, anterior venous wall tenting length, and needle angle were measured, and posterior venous wall penetration was determined. Eleven cannulations in 56 patients were assigned to posterior venous wall penetration. Small venous diameter (p = 0.004), and long anterior venous wall tenting (p = 0.007) were associated with posterior venous wall penetration. The longer anterior venous tenting would be expected with reducing needle angle (p = 0.004) or increasing anterior venous wall thickness (p = 0.006). In conclusion, small IJV and anterior venous wall tenting lead to posterior venous wall penetration. Anterior venous wall tenting is longer with reducing needle angle, or increasing the anterior venous wall thickness. PMID:25365942

  12. Posterior iliac offset: description of a new radiological measurement of sacroiliac joint instability.

    PubMed

    Tonne, B M; Kempton, L B; Lack, W D; Karunakar, M A

    2014-11-01

    The purpose of this study was to describe the radiological characteristics of a previously unreported finding: posterior iliac offset at the sacroiliac joint and to assess its association with pelvic instability as measured by initial displacement and early implant loosening or failure. Radiographs from 42 consecutive patients with a mean age of 42 years (18 to 77; 38 men, four women) and mean follow-up of 38 months (3 to 96) with Anteroposterior Compression II injuries, were retrospectively reviewed. Standardised measurements were recorded for the extent of any diastasis of the pubic symphysis, widening of the sacroiliac joint, static vertical ramus offset and a novel measurement (posterior offset of the ilium at the sacroiliac joint identified on axial CT scan). Pelvic fractures with posterior iliac offset exhibited greater levels of initial displacement of the anterior pelvis (anterior sacroiliac widening, pubic symphysis diastasis and static vertical ramus offset, p < 0.001,0.034 and 0.028, respectively). Pelvic fractures with posterior ilium offset also demonstrated higher rates of implant loosening regardless of fixation method (p = 0.05). Posterior offset of the ilium was found to be a reliable and reproducible measurement with substantial inter-observer agreement (kappa = 0.70). Posterior offset of the ilium on axial CT scan is associated with greater levels of initial pelvic displacement and early implant loosening. PMID:25371470

  13. Lifting posterior mitral annuloplasty for enhancing leaflet coaptation in mitral valve repair: midterm outcomes

    PubMed Central

    Song, Meong Gun; Shin, Je Kyoun; Chee, Hyun Keun; Kim, Jun Seok; Yang, Hyun Suk

    2015-01-01

    Background We evaluated the midterm outcomes of lifting posterior mitral annuloplasty for enhancing leaflet coaptation in mitral valve repair. Methods Between October 2007 and December 2012, 341 consecutive patients with significant mitral regurgitation underwent lifting posterior mitral annuloplasty using a specially designed fabric annuloplasty strip that lifts the middle portion of the posterior annulus. Associated procedures for mitral valve repairs, such as patch valvuloplasty for posterior leaflet prolapse (n=80), new chord placement for anterior leaflet prolapse (n=33), commissurotomy (n=29), and posterior leaflet extension (n=23), were performed in 141 patients (41.3%). Results Thirty-day mortality was 0.9%. Nine late deaths (2.6%) occurred. Mean overall survival at 5 years was 96.0%±1.1%. During the mean follow-up period of 38±17 months, six patients (1.8%) underwent valve-related reoperation (5-year freedom from valve-related reoperation, 98.1%±0.8%). At 5 years, mean freedom from recurrence of mitral regurgitation grade 3+ to 4+ (moderate to severe) was 95.1%±1.6%. The mean valve pressure gradient (PG) was 3.2±1.5 mmHg across all strip sizes at the time of follow-up. Conclusions Lifting posterior mitral annuloplasty using an innovative annuloplasty strip in mitral valve repair has a low rate of recurrent regurgitation or valve-related reoperation with rare relevant complications. PMID:26309826

  14. Ossification of the Posterior Petroclinoid Dural Fold: A Cadaveric Study with Neurosurgical Significance.

    PubMed

    Kimball, David; Kimball, Heather; Matusz, Petru; Tubbs, R Shane; Loukas, Marios; Cohen-Gadol, A Aaron

    2015-08-01

    Objectives?The roof of the porus trigeminus, composed of the posterior petroclinoid dural fold, is an important landmark to the skull base surgeon. Ossification of the posterior petroclinoid dural fold is an anatomical variation rarely mentioned in the literature. Such ossification results in the trigeminal nerve traversing a bony foramen as it enters Meckel cave. The authors performed this study to better elucidate this anatomical variation. Design?Fifteen adult cadaveric head halves were subjected to dissection of the middle cranial fossa. Microdissection techniques were used to examine the posterior petroclinoid dural folds. Skull base osteology was also studied in 71 dry human skulls with attention paid to the attachment point of the posterior petroclinoid dural folds at the trigeminal protuberances. Setting?Cadaver laboratory Main Outcome Measures?Measurements were made using a microcaliper. Digital images were made of the dissections. Results?Completely ossified posterior petroclinoid folds were present in 20% of the specimens. Of the 142 dry skull sides examined, 9% had large trigeminal protuberances. Conclusions?Based on this study, the posterior petroclinoid dural fold may completely ossify in adults that may lead to narrowing of the porus trigeminus and potential compression of the trigeminal nerve at the entrance to Meckel cave. PMID:26225315

  15. Probability Problem 1. What is the probability that a random integer between 1 and 10000

    E-print Network

    Timorin, Vladlen

    Probability Problem 1. What is the probability that a random integer between 1 and 10000 contains 8 is the probability that Bob has had more heads than Alice? Problem 3. A box contains n white balls and m black balls. What is the probability that among k balls drawn randomly out of the box exactly r are white? Problem 4

  16. Accurate shear measurement with faint sources

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Luo, Wentao; Foucaud, Sebastien

    2015-01-01

    For cosmic shear to become an accurate cosmological probe, systematic errors in the shear measurement method must be unambiguously identified and corrected for. Previous work of this series has demonstrated that cosmic shears can be measured accurately in Fourier space in the presence of background noise and finite pixel size, without assumptions on the morphologies of galaxy and PSF. The remaining major source of error is source Poisson noise, due to the finiteness of source photon number. This problem is particularly important for faint galaxies in space-based weak lensing measurements, and for ground-based images of short exposure times. In this work, we propose a simple and rigorous way of removing the shear bias from the source Poisson noise. Our noise treatment can be generalized for images made of multiple exposures through MultiDrizzle. This is demonstrated with the SDSS and COSMOS/ACS data. With a large ensemble of mock galaxy images of unrestricted morphologies, we show that our shear measurement method can achieve sub-percent level accuracy even for images of signal-to-noise ratio less than 5 in general, making it the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys.

  17. Rico: An Accurate Cosmological Recombination Code

    E-print Network

    W. A. Fendt; J. Chluba; J. A. Rubino-Martin; B. D. Wandelt

    2008-07-16

    We present Rico, a code designed to compute the ionization fraction of the Universe during the epoch of hydrogen and helium recombination with an unprecedented combination of speed and accuracy. This is accomplished by training the machine learning code Pico on the calculations of a multi-level cosmological recombination code which self-consistently includes several physical processes that were neglected previously. After training, Rico is used to fit the free electron fraction as a function of the cosmological parameters. While, for example at low redshifts (zrecombination code in the standard cosmological parameter estimation framework without the need to add new or refined fudge factors or functions to a simple recombination model. Within the new approach presented here it is easy to update Rico whenever a more accurate full recombination code becomes available. Once trained, Rico computes the cosmological ionization history with negligible fitting error in ~10 milliseconds, a speed-up of at least 10^6 over the full recombination code that was used here. Also Rico is able to reproduce the ionization history of the full code to a level well below 0.1%, thereby ensuring that the theoretical power spectra of CMB fluctuations can be computed to sufficient accuracy and speed for analysis from upcoming CMB experiments like Planck. Furthermore it will enable cross-checking different recombination codes across cosmological parameter space, a comparison that will be very important in order to assure the accurate interpretation of future cosmic microwave background data.

  18. Probability-based stability robustness assessment of controlled structures

    SciTech Connect

    Field, R.V. Jr.; Voulgaris, P.G.; Bergman, L.A.

    1996-01-01

    Model uncertainty, if ignored, can seriously degrade the performance of an otherwise well-designed control system. If the level of this uncertainty is extreme, the system may even be driven to instability. In the context of structural control, performance degradation and instability imply excessive vibration or even structural failure. Robust control has typically been applied to the issue of model uncertainty through worst-case analyses. These traditional methods include the use of the structured singular value, as applied to the small gain condition, to provide estimates of controller robustness. However, this emphasis on the worst-case scenario has not allowed a probabilistic understanding of robust control. In this paper an attempt to view controller robustness as a probability measure is presented. The probability of failure due to parametric uncertainty is estimated using first-order reliability methods (FORM). It is demonstrated that this method can provide quite accurate results on the probability of failure of actively controlled structures. Moreover, a comparison of this method to a suitability modified structured singular value robustness analysis in a probabilistic framework is performed. It is shown that FORM is the superior analysis technique when applied to a controlled three degree-of-freedom structure. In addition, the robustness qualities of various active control design schemes such as LQR, H{sub 2}, H {sub oo}, and {mu}-synthesis is discussed in order to provide some design guidelines.

  19. Non-Parametric Collision Probability for Low-Velocity Encounters

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell

    2007-01-01

    An implicit, but not necessarily obvious, assumption in all of the current techniques for assessing satellite collision probability is that the relative position uncertainty is perfectly correlated in time. If there is any mis-modeling of the dynamics in the propagation of the relative position error covariance matrix, time-wise de-correlation of the uncertainty will increase the probability of collision over a given time interval. The paper gives some examples that illustrate this point. This paper argues that, for the present, Monte Carlo analysis is the best available tool for handling low-velocity encounters, and suggests some techniques for addressing the issues just described. One proposal is for the use of a non-parametric technique that is widely used in actuarial and medical studies. The other suggestion is that accurate process noise models be used in the Monte Carlo trials to which the non-parametric estimate is applied. A further contribution of this paper is a description of how the time-wise decorrelation of uncertainty increases the probability of collision.

  20. Basophile: Accurate Fragment Charge State Prediction Improves Peptide Identification Rates

    SciTech Connect

    Wang, Dong; Dasari, Surendra; Chambers, Matthew C.; Holman, Jerry D.; Chen, Kan; Liebler, Daniel; Orton, Daniel J.; Purvine, Samuel O.; Monroe, Matthew E.; Chung, Chang Y.; Rose, Kristie L.; Tabb, David L.

    2013-04-08

    In shotgun proteomics, database search algorithms rely on fragmentation models to predict fragment ions that should be observed for a given peptide sequence. The most widely used strategy (Naive model) is oversimplified, cleaving all peptide bonds with equal probability to produce fragments of all charges below that of the precursor ion. More accurate models, based on fragmentation simulation, are too computationally intensive for on-the-fly use in database search algorithms. We have created an ordinal-regression-based model called Basophile that takes fragment size and basic residue distribution into account when determining the charge retention during CID/higher-energy collision induced dissociation (HCD) of charged peptides. This model improves the accuracy of predictions by reducing the number of unnecessary fragments that are routinely predicted for highly-charged precursors. Basophile increased the identification rates by 26% (on average) over the Naive model, when analyzing triply-charged precursors from ion trap data. Basophile achieves simplicity and speed by solving the prediction problem with an ordinal regression equation, which can be incorporated into any database search software for shotgun proteomic identification.