Modeling and classification of natural sounds by product codehidden Markov models

Linear predictive coding (LPC), vector quantization (VQ), and hidden Markov models (HMMs) are three popular techniques from speech recognition which are applied in modeling and classifying nonspeech natural sounds. A new structure called the product code HMM uses two independent HMM per class, one for spectral shape and one for gain. Classification decisions are made by scoring shape and gain index sequences from a product code VQ. In a series of classification experiments, the product code structure outperformed the conventional structure, with an accuracy of over 96% for three classes     

Iris segmentation in non-ideal images using graph cuts

A non-ideal iris image segmentation approach based on graph cuts is presented that uses both the appearance and eye geometry information. A texture measure based on gradients is computed to discriminate between eyelash and non-eyelash regions, combined with image intensity differences between the iris, pupil, and the background (region surrounding the iris) are utilized as cues for segmentation. The texture and intensity distributions for the various regions are learned from histogramming and explicit sampling of the pixels estimated to belong to the corresponding regions. The image is modeled as a Markov Random Field and the energy minimization is achieved via graph cuts to assign each image pixel one of the four possible labels: iris, pupil, background, and eyelash. Furthermore, the iris region is modeled as an ellipse, and the best fitting ellipse to the initial pixel based iris segmentation is computed to further refine the segmented region. As a result, the iris region mask and the parameterized iris shape form the outputs of the proposed approach that allow subsequent iris recognition steps to be performed for the segmented irises. The algorithm is unsupervised and can deal with non-ideality in the iris images due to out-of-plane rotation of the eye, iris occlusion by the eyelids and the eyelashes, multi-modal iris grayscale intensity distribution, and various illumination effects. The proposed segmentation approach is tested on several publicly available non-ideal near infra red (NIR) iris image databases. We compare both the segmentation error and the resulting recognition error with several leading techniques, demonstrating significantly improved results with the proposed technique.     

Nanostructured ceramics for biomedical implants

Recent progress in the synthesis, characterization, and biological compatibility of nanostructured ceramics for biomedical implants is reviewed. A major goal is to develop ceramic coating technology that can reduce the friction and wear in mating total joint replacement components, thus contributing to their significantly improved function and longer life span. Particular attention is focused on the enhancement of mechanical properties such as hardness, toughness, and friction coefficient and on the bioactivity as they pertain to the nanostructure of the material. The development of three nanostructured implant coatings is discussed: diamond, hydroxyapatite, and functionally graded metalloceramics based on the Cr-Ti-N ternary system. Nanostructured diamond produced by chemical vapor deposition (CVD) techniques and composed of nano-size diamond grains have particular promise because of the combination of ultrahigh hardness, improved toughness over conventional microcrystalline diamond, low friction, and good adhesion to titanium alloys. Nanostructured processing applied to hydroxyapatite coatings is used to achieve the desired mechanical characteristics and enhanced surface reactivity and has been found to increase osteoblast adhesion, proliferation, and mineralization. Finally, nanostructured metalloceramic coatings provide continuous variation from a nanocrystalline metallic bond at the interface to the hard ceramic bond on the surface and have the ability to overcome adhesion problems associated with ceramic hard coatings on metallic substrates.     

Monitoring furosemide in racehorses participating in an EIPH program

We report a rare case of temporary and severe hypercalcemia: the patient, a 69-year-old woman, was admitted to Osaka City University Hospital on July 25, 1992, for severe hypercalcemia. The laboratory data on admission revealed severe hypercalcemia (14.9 mg/dl) and renal dysfunction with increased serum creatinine level (2.9 mg/dl). The urinary excretion of pyridinoline and deoxypyridinoline was increased, and serum levels of parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D were decreased. The data suggested that increased bone resorption was a probable main factor in the development of the hypercalcemia. The development of hypercalcemia seemed to be of acute onset because of (1) her severe symptoms caused by hypercalcemia and (2) impaired renal function which was improved after normalization of serum calcium level. Combination therapy with saline infusion and furosemide was administered, and there was a gradual decrease and subsequent normalization of serum calcium level along with serum creatinine. Even 8 months after discontinuation of the therapy for hypercalcemia, the serum calcium level remained within the normal range. The measured values of serum factors which are suspected to have a hypercalcemic effect, such as PTH, parathyroid hormone-related peptide and the cytokines (interleukin-1 alpha, interleukin-1 beta, interleukin-2, interleukin-6 and tumor necrosis factor-alpha) were all within the normal range. In summary, the hypercalcemia in this patient was regarded to be a type of disequilibrium hypercalcemia due to a combination of increased bone resorption and decreased renal capacity to excrete calcium. Furthermore, since it was temporary and did not recur even in the absence of treatment, the hypercalcemia was concluded to have developed due to an imbalance in calcium regulation rather than as a result of organic disease.     

Detection of coronary stenoses on source and projection images using three-dimensional MR angiography with retrospective respiratory gating: preliminary experience

OBJECTIVE: Our objective was to study the ability of three-dimensional MR angiography with retrospective respiratory gating to reveal stenoses in proximal coronary arteries on source and projection images. CONCLUSION: Proximal coronary artery stenoses can be identified using three-dimensional MR angiography with retrospective respiratory gating, both with projection images and on source images alone. Reasons for missed lesions included collateral vessels and retrograde flow distal to complete occlusion and volume averaging of vessels with adjacent structures. Causes of false-positive interpretations included small foci of decreased signal intensity distal to complete occlusion, partial volume effects on individual partitions, and regions of distal vessels leaving the imaging plane.     

Examination of age-related deficits on the Wisconsin Card Sorting Test.

Adult age differences in Wisconsin Card Sorting Test (WCST) measures were examined before and after statistical control of age-related differences in measures of feedback usage, working memory, and perceptual-comparison speed. The proportion of age-related variance associated with a summary measure of WCST performance was greatly reduced after controlling for measures of feedback usage, working memory, and perceptual-comparison speed. Furthermore, the age-related variance associated with the feedback-usage measure was reduced after controlling for working memory and perceptual-comparison speed measures. These results are consistent with the idea that age-related performance differences in the WCST are partially mediated by adult age differences in feedback usage and that age differences in feedback usage are mediated by age differences in working memory, which are in turn mediated by age-related reductions in processing speed, indexed by measures of perceptual-comparison speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dysgerminoma in an Arabian filly

Late onset cytomegalovirus (CMV) disease (occurring more than 1 year post-transplant] was documented in two liver transplant recipients with recurrent hepatitis C virus hepatitis in the absence of factors known to precipitate CMV disease, i.e., primary acquisition of CMV, allograft rejection, augmented immunosuppression, concomitant infections, or blood transfusions. Both patients had CMV enteritis (with CMV adrenalitis in one case]; however, other symptoms and signs of overt CMV infection, i.e., fever, leukopenia, or atypical lymphocytes, were lacking. Hepatitis C virus is an immunomodulatory virus; impaired CMV-specific T-cell responses may have accounted for the predisposition of our patients to unprovoked, late onset CMV disease. Given the high incidence of hepatitis C virus recurrence after liver transplantation, awareness of the occurrence and recognition of the unusual presentation of CMV disease in this setting is both clinically relevant and significant, particularly since CMV is treatable if recognized promptly.     

Compensatory recruitment of neural resources during overt rehearsal of word lists in Alzheimer's disease.

Functional neuroanatomical correlates subserving maintenance rehearsal relative to a reading control task were investigated with positron emission tomography imaging of cerebral blood flow in 6 healthy older participants and 6 patients with mild Alzheimer's disease (AD). Rehearsal and reading rates and number of unique words rehearsed did not differ significantly for the 2 groups. The right dorsolateral prefrontal cortex was activated in both groups during rehearsal, highlighting this region's role in short-term maintenance of verbal information. A shift in cortical processing resources to more anterior brain regions with increased rehearsal list length was seen, likely reflecting greater demands on frontal cortex as cognitive load grows. Whereas controls showed unilateral right frontal activation during rehearsal, AD patients demonstrated bilateral frontal activation, possibly reflecting compensatory recruitment of neural resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling of the ElectriCOIL system

Theoretical studies have indicated that sufficient fractions of O/sub 2/(/sup 1//spl Delta/) may be produced in an electrical discharge that will permit lasing of an electric discharge oxygen-iodine laser (ElectriCOIL) system. Results of those studies along with more recent experimental results show that electric excitation is a very complicated process that must be investigated with advanced diagnostics along with modeling to better understand this highly complex system. A kinetic package appropriate for the ElectriCOIL system is presented and implemented in the detailed electrodynamic GlobalKin model and the Blaze II chemical laser modeling code. A parametric study with the Blaze II model establishes that it may be possible to attain positive gain in the ElectriCOIL system, perhaps even with subsonic flow. The Blaze II model is in reasonable agreement with early gain data. Temperature is a critical issue, especially in the subsonic cases, and thus it appears that supersonic flow will be important for the ElectriCOIL system. Simulations of a supersonic ElectriCOIL system indicate that it may be possible to attain reasonable performance levels, even at low yield levels of 20% or less. In addition, pre-dissociation of the iodine is shown to be very important for the supersonic flow situation.