Selecting a restoration technique to minimize OCR error

This paper introduces a learning problem related to the task of converting printed documents to ASCII text files. The goal of the learning procedure is to produce a function that maps documents to restoration techniques in such a way that on average the restored documents have minimum optical character recognition error. We derive a general form for the optimal function and use it to motivate the development of a nonparametric method based on nearest neighbors. We also develop a direct method of solution based on empirical error minimization for which we prove a finite sample bound on estimation error that is independent of distribution. We show that this empirical error minimization problem is an extension of the empirical optimization problem for traditional M-class classification with general loss function and prove computational hardness for this problem. We then derive a simple iterative algorithm called generalized multiclass ratchet (GMR) and prove that it produces an optimal function asymptotically (with probability 1). To obtain the GMR algorithm we introduce a new data map that extends Kesler's construction for the multiclass problem and then apply an algorithm called Ratchet to this mapped data, where Ratchet is a modification of the Pocket algorithm . Finally, we apply these methods to a collection of documents and report on the experimental results.     

Malignant infantile osteopetrosis: otolaryngological complications and management

This study evaluated the influence of precocious exposure to hypergravity on the expression of myosin heavy chain (MHC) protein isoforms in nape, masticatory and respiratory developmental rat muscles. Pregnant females were maintained at 1.8 g from the 11th day of gestation to the 7th day after birth. The 7-day-old rats were used for muscle sampling. Hypergravity induced a marked decrease in the weight and protein content of all six muscles. Three MHC isoforms were detected in the young rats' muscles: embryonic (E), perinatal (P) and slow type 1 MHC. In centrifuged nape and masticatory muscles, there was a decrease in MHC E and an increase in P without reduction (indeed, even an increase) in MHC 1, whereas in the respiratory muscle MHC E was increased and MHC 1 decreased. These results indicate that hypergravity produces important changes in the contractile properties not only of antigravity muscles but also masticatory and respiratory muscles. MHC P has a higher shortening velocity than MHC E, which has a higher one than MHC 1. The hypergravity-induced transformations of MHC isoforms would thus lead to increased velocity of all muscles studied. In spite of the observation of a hypergravity-induced muscle hypotrophy, the results of this study reflect the adaptational properties of developing muscles to increased gravitational forces.     

Anismus: fact or fiction?

PURPOSE: Although anismus has been considered to be the principal cause of anorectal outlet obstruction, it is doubtful whether contraction of the puborectalis muscle during straining is paradoxical. The present study was conducted to answer this question. METHODS: During the first part of the study, we retrospectively reviewed 121 patients with constipation and/or obstructed defecation (male:female, 10/111; median age, 51 years). All of these patients underwent electromyography (EMG) of the pelvic floor and the balloon expulsion test (BET) in the left lateral position. Evacuation proctography was performed in all of these patients in the sitting position. Both the posterior anorectal angle and the central anorectal angle were measured. EMG and BET were also performed in ten controls (male:female, 4/6; median age, 47). In 147 patients with fecal incontinence (male:female, 24/123; median age, 58) only EMG activity was recorded. Criteria for anismus during straining were increase or insufficient (<20 percent) decrease of EMG activity, failure to expel an air-filled balloon on BET, and decrease or insufficient (<5 percent) increase of anorectal angle on evacuation proctography. Between June 1994 and March 1995, we conducted a second prospective study in a consecutive series of 49 patients with constipation and/or obstructed defecation and 28 patients with fecal incontinence. Both groups were compared with 19 control subjects. In this study, all three tests were performed. EMG and BET were performed both in the left lateral position and in the sitting position. RESULTS: The retrospective study was undertaken by comparing the constipated patients with the incontinent patients and the controls, and the anismus detected by EMG was found in, respectively, 60, 46, and 60 percent. Failure to expel the air-filled balloon was observed in 80 constipated patients (66 percent) and in 9 control subjects (90 percent). Based on posterior anorectal angle and central anorectal angle measurements, anismus was diagnosed in, respectively, 21 and 35 percent of constipated patients. In the prospective study, none of the tests showed significant differences regarding the prevalence of anismus between the two subgroups of patients and the control subjects. The prevalence of anismus only differed between constipated and incontinent patients when the diagnosis was based on BET in the sitting position (67 vs. 32 percent; P < 0.005). Our study shows that contraction of the puborectalis muscle during straining is not exclusively found in patients with constipation and/or obstructed defecation. The three tests most commonly used for the diagnosis of anismus showed an extremely poor agreement. CONCLUSION: Based on these findings, we doubt the clinical significance of anismus.     

Establishing a link between cultural evolution and sexually transmitted diseases

Measurement results of click evoked otoacoustic emissions (EOAE) and distortion products otoacoustic emissions (DPOAE) in a case of sensorineural hearing loss in a case of sensorineural hearing loss in a patient with a history of oticus zoster with nerve VII palsy are presented. Feasibility of using otoacoustic emissions measurements for hearing loss type identification is discussed.     

Burkholderia cepacia bacteremia: a retrospective analysis of 70 episodes

Burkholderia cepacia, a widespread gram-negative environmental bacillus associated with nosocomial infections, is considered to be of relatively low virulence and rarely to cause invasive disease. We retrospectively analyzed the risk factors, clinical manifestations, antimicrobial susceptibilities, and prognostic factors of B. cepacia bacteremia cases. From 1982 through 1995, 70 episodes of bacteremia due to B. cepacia occurred in 52 patients at the National Taiwan University Hospital. The overall case fatality rate was 11%. Sixty-four episodes were nosocomial infections. The common predisposing conditions were stay in an intensive care unit (61%) and invasive procedures, including urinary catheter (54%), intravenous catheter (70%), and intubation (57%). Three episodes involved polymicrobial bacteremia. In 41 episodes in which the infectious focus was identified, the respiratory tract was the most common portal of entry (17/41) followed by intravascular catheters (11/41). Most strains tested were susceptible to ceftazidime (95%), piperacillin (93%), minocycline (85%), and cefotaxime (82%); but most were resistant to aminoglycosides, tetracycline, carbenicillin, and ticarcillin. For empirical therapy of B. cepacia bacteremia, ceftazidime or piperacillin should be the drug of choice.     

A prospective clinical and electrophysiologic survey of acute flaccid paralysis in Chinese children

We studied 29 children admitted to Beijing Children's Hospital (BCH) with acute flaccid paralysis between June 1991 and June 1993. Twenty-seven patients had Guillain-Barré syndrome--7 with acute inflammatory demyelinating polyneuropathy and 20 with acute motor axonal neuropathy (AMAN). Two had poliomyelitis. The most common cause of acute flaccid paralysis at BCH is the AMAN pattern of GBS.     

Predicting failure of thoracic vertebrae with simulated and actual metastatic defects

Indications for operative treatment in spinal metastatic disease depend on estimates of vertebral loadbearing capacity. There are no noninvasive diagnostic tools for estimating vertebral loadbearing capacity in the presence of a metastatic lesion. Thus, relationships between vertebral failure load and measurements from computed tomography data were investigated to determine if measurements that account for defect size and bone density can predict loadbearing capacity better than can defect size alone. Cylindrical defects were created in thoracic vertebrae of 20 anatomic specimen spinal segments, with 10 other segments serving as controls. Five vertebrae with actual metastatic defects also were tested. Vertebrae were scanned using quantitative computed tomography, and the defect size and the axial rigidity of the midvertebral cross section were calculated using an image analysis program. The spinal segments were tested to failure using a combination of axial compression and anterior flexion. Linear regressions between axial rigidity and absolute failure load showed a high positive correlation, but there was no correlation between defect size and failure load. Axial rigidity may prove useful as a noninvasive assessment of vertebral loadbearing capacity in patients with spinal metastatic disease.     

The effect of vitamin D supplementation on the bone mineral density of the femoral neck is associated with vitamin D receptor genotype

Recent studies suggest that variations of the vitamin D receptor (VDR) gene are related to bone mineral density (BMD). In this study, we examined the effect of vitamin D3 supplementation on BMD at the femoral neck in relation to VDR genotype. We analyzed 81 women, age 70 years and over, who participated in a placebo-controlled clinical trial on the effect of vitamin D3 supplementation (400 IU daily for at least 2 years) on BMD and fracture incidence. VDR genotype was based on the presence (b) or absence (B) of the BsmI restriction site. Mean BMD of the right and left femoral neck was measured at baseline and after 1 and 2 years. Dietary calcium, body mass index, and years since menopause were assessed at baseline while biochemical markers were measured at baseline and after 1 year. There was no difference among the BB, Bb, and bb genotype for baseline measurements of BMD at the femoral neck (mean and SD, g/cm2: 0.70 (0.10), 0.71 (0.12), and 0.69 (0.10), respectively), nor for any of the biochemical indices. The mean increase of BMD in the vitamin D group relative to the placebo group, expressed as percentage of baseline BMD, was significantly higher (p = 0.03) in the BB (delta BMD: 4.4%, p = 0.04) and Bb genotype (delta BMD: 4.2%, p = 0.007) compared with the bb genotype (delta BMD: -0.3%, p = 0.61). No significant changes were found for any of the other measured parameters. The VDR genotype-dependent effect of vitamin D supplementation in these elderly subjects suggest a functional involvement of VDR gene variants in determining BMD.     

Functional differences in the interaction of arrestin and its splice variant, p44, with rhodopsin

Arrestin quenches signal transduction in rod photoreceptors by blocking the catalytic activity of photoactivated phosphorylated rhodopsin toward the G protein, transducin (Gt). Rod cells also express a splice variant of arrestin, termed p44, in which the last 35 amino acids are replaced by a single Ala. In contrast to arrestin, this protein has been reported to bind to both the phosphorylated and nonphosphorylated forms of the activated receptor. In this study, we analyzed formation of the rhodopsin-p44 complex in vitro. Like arrestin, p44 stabilized the meta II (MII) photoproduct relative to forms MI and MIII and did not interact measurably with the apoprotein opsin. However, several differences between p44 and its parent protein were found: (i) p44 binds to nonphosphorylated MII with a much lower affinity (KD = 0.24 microM) than to phosphorylated MII (P-MII) (KD = 12 nM); arrestin binds only to P-MII (KD = 20 nM); (ii) p44 interacted also with truncated MII (329G-Rho MII), which lacked the sites of phosphorylation; (iii) with both MII and P-MII, the activation energy of complex formation with p44 was lower than that found for arrestin (70 kJ/mol instead of 140 kJ/mol); and (iv) InsP6 inhibited poorly the interaction between p44 and P-MII, but it strongly inhibited the interaction between arrestin and P-MII. Extrapolation of the measured on-rates to physiological conditions yielded reaction times for the binding of p44 to activated rhodopsin. The data suggest that the splice variant, p44, and its parent protein, arrestin, play different roles in phototransduction. The physiological significance of these differences remains to be determined.