Tree-structured piecewise linear adaptive equalization

The use of a tree-structured piecewise linear filter as an adaptive equalizer is proposed. In the tree equalizer, each node in a tree is associated with a linear filter restricted to a polygonal domain, and each subtree is associated with a piecewise linear filter. A training sequence is used to adaptively update the filter coefficients and domains at each node, and to select the best subtree and corresponding piecewise linear filter. The tree-structured approach offers several advantages. First, it makes use of standard linear adaptive filtering techniques at each node to find the corresponding conditional linear filter. Second, it allows for efficient selection of the subtree and corresponding piecewise linear filter of appropriate complexity. Overall, the approach is computationally efficient and conceptually simple. Numerical experiments are performed to show the advantages of tree-structured piecewise linear and piecewise decision feedback equalizers over linear, polynomial, and decision feedback equalizers for the equalization of channels with severe intersymbol interference     

Comparison between morphologic changes seen on high-resolution CT and regional pulmonary perfusion seen on SPECT in patients with cystic fibrosis

OBJECTIVE: To evaluate the relationship between morphologic findings seen on high-resolution computed tomography (HRCT) of the lung and regional lung perfusion depicted on single photon-emission computed tomography (SPECT) pulmonary perfusion imaging in patients with cystic fibrosis. MATERIALS AND METHODS: Ten HRCT and 10 technetium-99 m macroaggregated albumin SPECT pulmonary perfusion imaging studies were performed on eight young adult patients who were considered to be clinically well and have mild to moderate cystic fibrosis. HRCT scans of the chest were evaluated using a CT scoring system which included grading of bronchiectasis, peribronchial thickening, hyperlucency, bullae, collapse/consolidation, and mucus plugging. Each lung was divided into six anatomic zones which were independently scored. A lung perfusion score (between 0 and 100), reflecting the percentage of compromised lung, was estimated for each zone. Axial lung perfusion SPECT images were matched anatomically to HRCT images. Lung function was considered compromised when the counts per pixel were less than 25 % of the count level seen in an area of the same patient's lung which was judged to be normal. RESULTS: There was a statistically significant relationship (P = 0.0001) between HRCT total scores and SPECT lung perfusion scores as well as between hyperlucency scores by HRCT and the SPECT lung perfusion scores. However, the HRCT score was a poor predictor of the lung perfusion score in zones with intermediate HRCT scores, which constituted 106 of 120 zones. CONCLUSION: Morphologic changes depicted by HRCT correlate with decreased lung pefusion on SPECT. However, HRCT changes accurately predict regional lung function only in the most normal and severely diseased lung zones.     

Methotrexate treatment of idiopathic granulomatous hepatitis

OBJECTIVE: To test the efficacy and safety of low-dose oral pulse methotrexate therapy in patients with idiopathic granulomatous hepatitis who had complications of, did not respond to, or refused glucocorticoid therapy. DESIGN: Prospective case study. SETTING: Academic medical center hospital. PATIENTS: Seven patients with biopsy-proven, idiopathic granulomatous hepatitis who could not tolerate or were unresponsive to glucocorticoid therapy. INTERVENTION: Low-dose oral pulse methotrexate, 15 mg/wk. MEASUREMENTS: Temperature, symptoms, dose of concurrent glucocorticoids, biochemical tests of liver function, side effects of methotrexate, and assessment of liver biopsy specimens. RESULTS: All six febrile patients became afebrile within 3 months of starting methotrexate. Fatigue and anorexia improved in all patients. Glucocorticoid therapy was successfully discontinued within 6 months of starting methotrexate in four patients receiving prednisone at entry. Liver biopsy specimens were obtained again after methotrexate therapy and showed absence of granulomas in four of four patients. The minimum effective dose of methotrexate was 0.20 mg/kg body weight per week. No serious adverse effects and no failures to respond to methotrexate therapy were noted in this group of patients. In three patients, methotrexate therapy has been successfully tapered without signs or symptoms of recurrent disease. CONCLUSIONS: Low-dose oral pulse methotrexate was effective in treating patients with granulomatous hepatitis.     

Regulation of organelle movement in melanophores by protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2A (PP2A)

We used melanophores, cells specialized for regulated organelle transport, to study signaling pathways involved in the regulation of transport. We transfected immortalized Xenopus melanophores with plasmids encoding epitope-tagged inhibitors of protein phosphatases and protein kinases or control plasmids encoding inactive analogues of these inhibitors. Expression of a recombinant inhibitor of protein kinase A (PKA) results in spontaneous pigment aggregation. alpha-Melanocyte-stimulating hormone (MSH), a stimulus which increases intracellular cAMP, cannot disperse pigment in these cells. However, melanosomes in these cells can be partially dispersed by PMA, an activator of protein kinase C (PKC). When a recombinant inhibitor of PKC is expressed in melanophores, PMA-induced pigment dispersion is inhibited, but not dispersion induced by MSH. We conclude that PKA and PKC activate two different pathways for melanosome dispersion. When melanophores express the small t antigen of SV-40 virus, a specific inhibitor of protein phosphatase 2A (PP2A), aggregation is completely prevented. Conversely, overexpression of PP2A inhibits pigment dispersion by MSH. Inhibitors of protein phosphatase 1 and protein phosphatase 2B (PP2B) do not affect pigment movement. Therefore, melanosome aggregation is mediated by PP2A.     

Finite-size effects in surface tension: Thermodynamics and the Gaussian interface model

It has been suggested by Kayser that finite-size effects associated with capillary waves might play a significant role in some surface tension measurements; for capillary rise between plates a distance D apart, an effect varying as 1/D and apparently observable in measurements, was proposed. In reconsidering this problem, one must analyze the thermodynamics of finite-size corrections to surface tension. In particular, one sees that capillary rise between plates does not measure the interfacial free energy density but, rather, a derivative of the interfacial free energy with respect to a system dimension. The quantity needed to draw definite conclusions, the finite-size residual free energy, can be calculated within the harmonic or Gaussian capillary wave model in d spatial dimensions with the aid of Poisson summation techniques and should yield the correct leading asymptotic behavior. For d=3 and experimentally relevant parameter values, the results are independent of the short-wavelength cutoff needed in the model and can be checked against the theory of conformai covariance at two-dimensional critical points. It is found that the finite-size effects in capillary-rise measurements of surface tension vary as 1/D ² (with a universal coefficient) but are too small to be seen in current experiments.Invited paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

Viewfinder Alignment

The viewfinder of a digital camera has traditionally been used for one purpose: to display to the user a preview of what is seen through the camera's lens. High quality cameras are now available on devices such as mobile phones and PDAs, which provide a platform where the camera is a programmable device, enabling applications such as online computational photography, computer vision‐based interactive gaming, and augmented reality. For such online applications, the camera viewfinder provides the user's main interaction with the environment. In this paper, we describe an algorithm for aligning successive viewfinder frames. First, an estimate of inter‐frame translation is computed by aligning integral projections of edges in two images. The estimate is then refined to compute a full 2D similarity transformation by aligning point features. Our algorithm is robust to noise, never requires storing more than one viewfinder frame in memory, and runs at 30 frames per second on standard smartphone hardware. We use viewfinder alignment for panorama capture, low‐light photography, and a camera‐based game controller.     

Converging measurement of horizontal and vertical individualism and collectivism.

The constructs of horizontal (H) and vertical (V) individualism (I) and collectivism (C) were theoretically defined and empirically supported. Study 1 confirmed, via factor analysis, that the 4 constructs, HI, V1, HC, and VC, which were previously found in the United States, which has an individualist culture, also were found in Korea which has a collectivist culture. Study 2 investigated multimethod-multitrait matrices measuring the constructs and generally supported their convergent and divergent validity. Study 3 showed how these 4 constructs relate to previously identified components by H. C. Triandis and colleagues. Study 4 showed the relationships of the measurement of the 4 constructs to some of the measures used by other researchers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender differences in altruistic reputation: Are they artifactual?

Tested the notion that observed sex differences in children's altruistic reputations that favor girls are due to sex-biased items found in commonly used peer-assessment measures. A gender-fair assessment of altruistic reputation was attempted by including items that were empirically derived examples of masculine, feminine, and gender-neutral prosocial behaviors. These items were based on prosocial incidents reported by 65 5th graders. 123 additional 5th graders were asked to respond to the new items by nominating 2 classmates most likely to engage in prosocial behavior or by indicating which sex was most likely to perform the behaviors. Results show that, overall, females were judged to be more altruistic than males. However, endorsement differed across item content: Males were selected more often for masculine items and females more often for feminine and sex-neutral items. In general, males endorsed males for helpful behaviors and females endorsed females. The gender-rating form of the test produced responses more closely related to the empirically based item-gender-content classes than did the peer-nomination form. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditions of detonation initiation by focusing shock waves in a combustible gas mixture

Based on experiments on focusing shock waves in hydrogen-air mixtures and available publications, the critical shock-wave Mach number at which detonation is initiated near the apex of a concave reflector is analyzed as a function of the reflector size and reactivity of the mixture. The effect of the reflector shape and size on the value of this Mach number is studied. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 6, pp. 84–89, November–December, 2007.     

Geometric invariant core for the V(L) and V(H) domains of immunoglobulin molecules

A new algorithmic method for identifying a geometric invariant of protein structures, termed geometrical core, is developed. The method used the matrix of C(alpha)-C(alpha) distances and does not require the usual superposition of structures. The result of applying the algorithm to 53 immunoglobulin structures led to the identification of two geometrical core sets of C(alpha) atoms positions for the V(L) and V(H) domains. Based on these geometric invariants a preferred coordinate system for the immunoglobulin family is constructed which serves as a basis for structural prediction. The X-ray atom coordinates for all available immunoglobulin structures are transformed to the preferred coordinate system. An affine symmetry between the V(L) and V(H) domains is defined and computed for each of the 53 immunoglobulin structures.