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We consider how recently developed multi-resolution exploratory graphical models (MR-EGM) may be estimated in a practical real-world situation. A simple cross-validation procedure based on minimising predictive risk is presented as a means to estimate tuning parameters. Through the use of electroencephalography (EEG) data, we attempt to use such a procedure to build a generative (multi-resolution) model of the electrical dynamics in the brain throughout an epileptic seizure. Brain dynamics are analysed by projecting the estimated model parameters onto their principle components where we identify two clusters of seizure activity. To conclude, we discuss the interpretation of such a principle component analysis and how well we can generalise between seizures on a specific patient.

The automatic extraction of elongated curvilinear structures (CLSs) is an important task in various image processing applications, including numerous remote sensing, and biometrical and medical problems. To address this task, we develop a stochastic approach that relies on a fixed-grid, localized Radon transform for line segment extraction and a conditional random field model to incorporate local interactions and refine the extracted CLSs. We propose several different energy data terms, the appropriate choice of which allows us to process images with different noise and geometry properties. The contribution of this paper is the design of a flexible and robust elongated CLS extraction framework that is comparatively fast due to the use of a fixed-grid configuration and fast deterministic Radon-based line detector. We present several different applications of the developed approach, namely: 1) CLS extraction in mammographic images; 2) road networks extraction from optical remotely sensed images; and 3) line extraction from palmprint images. The experimental results demonstrate that the method is fairly robust to CLS curvature and can accurately extract blurred and low-contrast elongated CLS.

Because of the difficulty of obtaining an analytic expression for Bayes error, a wide variety of separability measures has been proposed for feature selection. In this paper, we show that there is a general framework based on the criterion of mutual information (MI) that can provide a realistic solution to the problem of feature selection for high-dimensional data. We give a theoretical argument showing that the MI of multi-dimensional data can be broken down into several one-dimensional components, which makes numerical evaluation much easier and more accurate. It also reveals that selection based on the simple criterion of only retaining features with high associated MI values may be problematic when the features are highly correlated. Although there is a direct way of selecting features by jointly maximising MI, this suffers from combinatorial explosion. Hence, we propose a fast feature-selection scheme based on a 'greedy' optimisation strategy. To confirm the effectiveness of this scheme, simulations are carried out on 16 land-cover classes using the 92AV3C data set collected from the 220-dimensional AVIRIS hyperspectral sensor. We replicate our earlier positive results (which used an essentially heuristic method for MI-based band-selection) but with much reduced computational cost and a much sounder theoretical basis.

In this paper, we describe a video tracking application using the dual-tree polar matching algorithm. The models are specified in a probabilistic setting, and a particle filter is used to perform the sequential inference. Computer simulations demonstrate the ability of the algorithm to track a simulated video moving target in an urban environment with complete and partial occlusions.

Fourier-based regularisation is considered for the support vector machine classification problem over absolutely integrable loss functions. By invoking the modest assumption that the decision function belongs to a Paley–Wiener space, it is shown that the classification problem can be developed in the context of signal theory. Furthermore, by employing the Paley–Wiener reproducing kernel, namely the sinc function, it is shown that a principled and finite kernel hyper-parameter search space can be discerned, a priori. Subsequent simulations performed on a commonly-available hyperspectral image data set reveal that the approach yields results that surpass state-of-the-art benchmarks.

Target detection from hyperspectral imagery requires the fusion of information from hundreds of spectral bands. In this paper, we study such fusion in the context of hyperspectral image classification. Previous research applying kernel methods such as support vector machines (SVMs) to hyperspectral image classification has achieved performance competitive with the best available algorithms. However, few efforts have so far been made to extend SVMs to fit the specific requirements of this application, e.g., by building tailor-made kernels. To this effect, we propose a novel spectrally weighted kernel. Observation of real-life spectral signatures from the AVIRIS hyperspectral dataset shows that the useful information for classification is not equally distributed across bands. Hence, we propose the use of spectrally weighted kernels to assign weights to different bands according to the amount of useful information they contain. We have carried out experiments on the AVIRIS 92AV3C dataset to assess the performance of the proposed method. Results show potential for improvement in classification accuracy.

Same-day discharge after endoscopic biliary sphincterotomy (ES) is a common clinical practice, but there have been few data to guide appropriate selection of patients. Using a prospective, multicenter database of complications, we examined outcomes after same-day discharge as it was practiced by a variety of endoscopists and evaluated the ability of a multivariate risk factor analysis to predict which patients would require readmission for complications.A 150-variable database was prospectively collected at time of ES, before discharge and again at 30 days in consecutive patients undergoing ES at 17 centers. Complications were defined by consensus criteria and included all specific adverse events directly or indirectly related to ES requiring more than 1 night of hospitalization.Six hundred fourteen (26%) of 2347 patients undergoing ES were discharged on the same day as the procedure, ranging from none at 6 centers to about 50% at 2 centers. After initial observation and release, readmission to the hospital for complications occurred in 35 (5.7%) of 614 same-day discharge patients (20 pancreatitis and 15 other complications, 3 severe). Of the same-day discharge patients, readmission was required for 14 (12.2%) of 115 who had at least one independently significant multivariate risk factor for overall complications (suspected sphincter of Oddi dysfunction, cirrhosis, difficult bile duct cannulation, precut sphincterotomy, or combined percutaneous-endoscopic procedure) versus 21 (4.2%) of 499 without a risk factor (odds ratio 3.1: 95% confidence interval [1.6, 6.3], p0.001). Of complications presenting within 24 hours after ES, only 44% presented within the first 2 hours, but 79% presented within 6 hours.Same-day discharge is widely utilized and relatively safe but results in a significant number of readmissions for complications. For patients at higher risk of complications, as indicated by the presence of at least one of five independent predictors, observation for 6 hours or overnight may reduce the need for readmission.

We investigate band selection for hyperspectral image classification. Mutual information (MI) measures the statistical dependence between two random variables. By modeling the reference map as one of the two random variables, MI can, therefore, be used to select the bands that are more useful for image classification. A new method is proposed to estimate the MI using an optimally constructed reference map, reducing reliance on ground-truth information. To reduce the interferences from noise and clutters, the reference map is constructed by averaging a subset of spectral bands that are chosen with the best capability to approximate the ground truth. To automatically find these bands, we develop a searching strategy consisting of differentiable MI, gradient ascending algorithm, and random-start optimization. Experiments on AVIRIS 92AV3C dataset and Pavia University scene dataset show that the proposed method outperformed the benchmark methods. In AVIRIS 92AV3C dataset, up to 55% of bands can be removed without significant loss of classification accuracy, compared to the 40% from that using the reference map accompanied with the dataset. Meanwhile, its performance is much more robust to accuracy degradation when bands are cut off beyond 60%, revealing a better agreement in the MI calculation. In Pavia University scene dataset, using 45 bands achieved 86.18% classification accuracy, which is only 1.5% lower than that using all the 103 bands.

This study was conducted to assess the acceptance of grapefruit juice which has undergone a debittering process. The sensory effect of debittering and the sensory attributes of sourness, sweetness, bitterness, and aftertaste were appraised, and the correlation between chemical and sensory analyses of the debittered juice were identified. The effect of added grapefruit flavor on perception of sweetness and sourness was statistically significant. Both the level of bitterness and storage duration of grapefruit were shown to influence the way judges perceived bitterness and sweetness. Storage study showed no difference in aftertaste, which may increase consumers buying interest in debittered juice with a high level of bitterness (450 ppm).

Currently, a wide variety of bio-occlusive dressing materials are available. In general, these dressing materials provide a moist wound healing environment that has been shown to promote healing in both human and animal studies. To effectively use these dressings the clinician must have a full understanding of the properties of the materials as well as the pathophysiology of the particular wound. Most recently, a "new" biosynthetic dressing material, the alginates, has become available.To highlight proper use of alginate dressings for the management of acute and chronic wounds.Case study and literature review.Alginates were shown to be effective in a wide variety of acute and chronic wounds.Alginates possess several unique properties that should prove useful to the dermatologic surgeon as well as the dermatologist. Proper patient selection and use of this "new" dressing material, as well as a review of the literature is presented.

We performed a prospective controlled trial of a monthly journal club to determine if it would increase pediatric residents' knowledge of clinical epidemiology and biostatistics.Intervention residents received two didactic sessions before the journal club started. Eight monthly journal club sessions followed. Pediatric residents at another institution served as controls. Intervention and control residents completed a pre- and post-test on clinical epidemiology and biostatistics.Neither the intervention nor the control group showed a significant change in test scores over the 9-month period.A more intensive and more structured approach is needed to effectively teach clinical epidemiology and biostatistics to residents.

Cyanoacrylate tarsorrhaphy is an easily administered, painless technique for the temporary management of corneal epithelial defects. We have used the technique in 17 patients to treat persistent epithelial defects and exposure keratitis, as well as following epikeratophakia, allowing the tarsorrhaphy to remain in place for 1 to 15 days (mean, 5.7 days). Eleven of the 17 patients required only one application of cyanoacrylate; five had additional cyanoacrylate applied at the time of the original tarsorrhaphy to produce more extensive lid closure; and one required additional cyanoacrylate on day 3 to produce more extensive lid apposition.

To determine if lower rubella susceptibility persisted five to seven years after immunization legislation, we retrospectively reviewed the serologic status of 341 outpatients from 1985 to 1987 in an inner-city school age population. Seronegative rates increased significantly during the two-year study period from 4.2 to 24.5 percent (17 percent overall). (Beta = 6.8%, 95% CI = 3.3, 10.3). Charts were reviewed for 57 of 58 seronegative and 114 seropositive controls. Estimates were then made to the population of 341 subjects. Those with documented rubella immunization had a seronegative rate of 13 percent compared to 19 percent if the immunization status was unknown. For patients who received care in our clinic for less than two years, 32 percent were seronegative compared to 10 percent for those treated greater than or equal to 2 years (odds ratio = 0.31, 95% CI = 0.16, 0.60). Among patients immunized in 1977 or 1978, 33 percent were seronegative compared to 7 percent immunized at other times (OR = 0.21, 95% CI = 0.07, 0.63). Factors associated with increased rubella seronegativity include immunization in 1977 or 1978 and lack of continuity of care in our clinic. Much of the increase remains unexplained.

An equation is derived that gives a necessary, as well as sufficient, stability criterion for the guiding center plasma to instabilities of large toroidal mode number. This equation is applied to D-shaped scalar pressure and beam-induced tensor pressure Tokamak equilibria of aspect ratio 3. The tensor and scalar pressure equilibria generated have comparable pressure profiles. The tensor pressure equilibria are valid in the limit that the beam particle injection energy EO>>Ec and (Zeff-1)<

We studied ballooning instabilities in tokamaks of arbitrary cross sections and finite shear. These azimuthally localized, ideal magnetohydrodynamic modes have large toroidal-mode numbers, but finite variation along the field and across the flux surfaces. Stability is determined by solving a second-order ordinary differential equation on each flux surface, subject to the proper boundary conditions. Qualitative agreement is achieved with the Princeton PEST stability code.

D-shaped tensor pressure tokamak equilibria induced by neutral-beam injection are computed. The beam pressure components are evaluated from the moments of a distribution function that is a solution of the Fokker-Planck equation in which the pitch-angle scattering operator is ignored. The level-p⊥ contours undergo a significant shift away from the outer edge of the device with respect to the flux surfaces for perpendicular beam injection into broad-pressure-profile equilibria. The p∥ contours undergo a somewhat smaller inward shift with respect to the flux surfaces for both parallel and perpendicular injection into broad-pressure-profile equilibria. For peaked-pressure-profile equilibria, the level pressure contours nearly co-incide with the flux surfaces.

A counterimmunoelectrophoresis test was developed for immunoglobulin M (IgM) antibodies to group B coxsackievirus (CB) types 1 through 5. The IgM precipitin line could be identified and differentiated from the IgG line by treating sera with 2-mercaptoethanol. Antigen purity was demonstrated by single precipitin lines occurring only to the homologous antigen when tested with type-specific hyperimmune rabbit sera. Serum pairs from 19 of 22 patients with documented CB type 1,3,4, and 5 infections were positive for IgM antibody to the infecting serotype, whereas 2 of 7 pairs from CB type 2 patients were positive. Heterologous IgM antibodies were present in sera from 14 fo 29 CB patients. Of the 14 patients with heterologous IgM antibodies, 12 also had greater than or equal to 4-fold rises in whole serum neutralizing antibody to heterologous serotypes. Only three control sera from 72 patients with coxsackievirus group A, echovirus, or other viral infections had IgM antibody to CB serotypes.

A second-order ordinary differential equation on each flux surface is derived for the high-mode-number limit of resistive magnetohydrodynamic (MHD) ballooning modes in tokamaks with arbitrary cross section, aspect ratio, and shear. The equation is structurally similar to that used to study ideal MHD ballooning modes computationally. The model used in this paper predicts linear instability in the high-mode-number limit, with growth rate proportional to resistivity when the pressure gradient is small compared with the critical value needed for ideal MHD stability.

Restriction enzyme analysis of cytomegalovirus deoxyribonucleic acid (DNA) has been used to characterise virus isolates and has provided information on patterns of viral transmission. It was shown that virus isolated from a congenitally infected infant was unlikely to have originated from the 13 congenitally infected children with whom the mother, a nurse, had been in contact. Of nine mother and infant pairs, from whom cytomegalovirus was isolated, seven yielded strains that were indistinguishable for mother and child; one pair showed minor differences and one was clearly distinguishable. Virus isolates from seven children attending a day nursery were typed, and only siblings were excreting similar strains of cytomegalovirus. Further examples of the application of this technique to studies of cytomegalovirus in a family environment are given. It is concluded that characterisation of virus strains by restriction analysis of DNA is a valuable epidemiological tool.

Necessary and sufficient criteria are obtained for the high toroidal mode number stability of a guiding center plasma in low aspect ratio, D-shaped, beam-induced tensor pressure tokamaks. The difference between the two criteria is significant for interchange stability, while the difference is small for ballooning stability. The critical ..beta.. value imposed by stability to ballooning modes is higher for perpendicular than for parallel beam injection.

ConclusionsThese studies have demonstrated that all 3 immunologic types of poliomyelitis virus may be propagated successfully in monkey kidney and skin tissue grafted onto embryonated egg membrane. No preliminary “adaptation” is necessary for virus multiplication in this system. Presence of virus is not limited to the grafted tissue but is found also in moderate concentration in the allantoic fluid, the CAM, and the embryo. However, this is probably due to spillage and dissemination from the grafts where virus growth apparently occurs. More precise knowledge is needed with reference to the exact sites of multiplication and the specific cells participating in this activity.Further studies are desirable to determine the practical and theoretical applications of this technic and whether simplification and improvements are possible.

From 8 August through 5 December 1977, 110 laboratory-documented cases (78 confirmed, 32 presumptive) of St. Louis encephalitis (SLE) occurred in 20 counties throughout central-south Florida. Most cases were initially identified through an active surveillance system involving repeated contact of hospital infection control officers. This outbreak had three characteristics that are unusual for SLE epidemics in the eastern United States: it lacked an urban focus, a disproportionate number of cases affected young males, and the epidemic period extended into December. There was no significant difference between attack rates for blacks and whites. Males were significantly more often affected than females. Because of the time required for laboratory confirmation of cases, most outbreak control measures were initiated after the outbreak was declining. Reporting of clinically suspected SLE cases to initiate epidemic mosquito control should improve the timeliness of control measures in future outbreaks.

In order to improve the immune status of girls in our medical clinic, we conducted a prospective sero-survey to identify susceptibles and developed a system for vaccinating non-immune girls. Over an 18-month period, 481 inner-city adolescents were screened. Susceptibility rate defined by a titer less than 1:8 was 12 per cent and did not differ significantly with regard to age or race. Nine months into the study period, the State of Wisconsin enacted a "no immunization-no school" law. The susceptibility rate dropped from 22 per cent prior to the enactment of the law, to 5 per cent after. Of the 60 girls identified as susceptible, 54 (90 per cent) kept their follow up appointments for vaccinations. Enforced state immunization laws appear to be effective in lowering rubella susceptibility.

Staphylococcal enterotoxin F (SEF) has previously been shown to be a marker for toxic-shock syndrome (TSS)-associated strains of Staphylococcus aureus, whereas the serologic absence of antibody to SEF (anti-SEF) has been shown to be a marker for susceptibility of persons to TSS. In this study, anti-SEF was measured by radioimmunoassay in 689 banked sera obtained from Wisconsin residents during 1960, 1970, and 1980. The prevalence of anti-SEF as estimated by logistic regression analysis was 47%, 58%, 70%, 88%, 96%, and 99% at ages one, five, 10, 20, 30, and 50 years, respectively. Evidence for the transplacental transfer of anti-SEF is also presented. Despite the reported increased incidence of TSS occurring during the past five years, with a preponderance of cases occurring among women, no significant differences in the prevalence of anti-SEF were noted between sexes or longitudinally between the years 1960, 1970, and 1980. These data enhance our understanding of the epidemiology of TSS and further identify the population that may be susceptible to TSS.

One hundred and seventeen children and 41 teachers in day nurseries were screened for cytomegalovirus (CMV) viruria over a period of one year. Thirty two (27%) children and two (5%) teachers were found to be excreting virus on at least one occasion. Restriction endonuclease typing showed that virus strains isolated from the children were dissimilar, with the exception of those from sibling pairs and one unrelated pair. The virus isolate from one teacher matched those from two unrelated children, while the isolate from another teacher could not be distinguished from that from a sibling pair. The CMV serological state of the 41 teachers was not significantly different from 500 matched controls and no seroconversions occurred. It is concluded that although transmission of CMV among children and teachers may occur in day nurseries, the dissimilarity of most of the virus strains indicates that infection predominantly occurs outside. Furthermore, teachers in day nurseries showed no evidence of an increased risk of past CMV infection when compared with matched controls.

In Minneapolis, 107 cases of hepatitis A were identified and traced primarily to consumption of cold sandwiches served for lunch in a department store's popular basement restaurant. A sandwich-maker in the restaurant was the index patient. The date of onset of her illness and the dates of food consumption and onset of illness of infrequent restaurant patrons were consistent with accepted periods of infectivity and incubation for hepatitis A. Because the sandwich-maker frequently touched her hands to her mouth when she worked, and because we could not find evidence for fecal, airborne, or other modes of transmission, we believe that she may have contaminated food with infectious oropharyngeal secretions. The secondary attack rate was much lower among household contacts who received immune serum globulin than among those who had not.

A force balance relation, a representation for the poloidal beta (..beta../sub p/), and expressions for the current densities are derived from the MHD equilibrium relations for an axisymmetric tensor pressure tokamak. Perpendicular and parallel beam pressure components are evaluated from a distribution function that models high energy neutral particle injection. A double adiabatic energy principle is derived from that of Kruskal and Oberman, with correction terms added. The energy principle is then applied to an arbitrary cross-section axisymmetric tokamak to examine ballooning instabilities of large toroidal mode number. The resulting Euler equation is remarkably similar to that of ideal MHD. Although the field-bending term is virtually unaltered, the driving term is modified because the pressures are no longer constant on a flux surface. Either a necessary or a sufficient marginal stability criterion for a guiding center plasma can be derived from this equation whenever an additional stabilizing element unique to the double adiabatic theory is either kept or neglected, respectively.