Showing papers by "Texas A&M University published in 1992"

An introduction to wavelets

Abstract: An Overview: From Fourier Analysis to Wavelet Analysis. The Integral Wavelet Transform and Time-Frequency Analysis. Inversion Formulas and Duals. Classification of Wavelets. Multiresolution Analysis, Splines, and Wavelets. Wavelet Decompositions and Reconstructions. Fourier Analysis: Fourier and Inverse Fourier Transforms. Continuous-Time Convolution and the Delta Function. Fourier Transform of Square-Integrable Functions. Fourier Series. Basic Convergence Theory and Poisson's Summation Formula. Wavelet Transforms and Time-Frequency Analysis: The Gabor Transform. Short-Time Fourier Transforms and the Uncertainty Principle. The Integral Wavelet Transform. Dyadic Wavelets and Inversions. Frames. Wavelet Series. Cardinal Spline Analysis: Cardinal Spline Spaces. B-Splines and Their Basic Properties. The Two-Scale Relation and an Interpolatory Graphical Display Algorithm. B-Net Representations and Computation of Cardinal Splines. Construction of Spline Approximation Formulas. Construction of Spline Interpolation Formulas. Scaling Functions and Wavelets: Multiresolution Analysis. Scaling Functions with Finite Two-Scale Relations. Direct-Sum Decompositions of L2(R). Wavelets and Their Duals. Linear-Phase Filtering. Compactly Supported Wavelets. Cardinal Spline-Wavelets: Interpolaratory Spline-Wavelets. Compactly Supported Spline-Wavelets. Computation of Cardinal Spline-Wavelets. Euler-Frobenius Polynomials. Error Analysis in Spline-Wavelet Decomposition. Total Positivity, Complete Oscillation, Zero-Crossings. Orthogonal Wavelets and Wavelet Packets: Examples of Orthogonal Wavelets. Identification of Orthogonal Two-Scale Symbols. Construction of Compactly Supported Orthogonal Wavelets. Orthogonal Wavelet Packets. Orthogonal Decomposition of Wavelet Series. Notes. References. Subject Index. Appendix.

Putting the fear back into fear appeals: The extended parallel process model

Abstract: The fear appeal literature is diverse and inconsistent Existing fear appeal theories explain the positive linear results occurring in many studies, but are unable to explain the boomerang or curvilinear results occurring in other studies The present work advances a theory integrating previous theoretical perspectives (ie, Janis, 1967; Leventhal, 1970; Rogers, 1975, 1983) that is based on Leventhal's (1970) danger control/fear control framework The proposed fear appeal theory, called the Extended Parallel Process Model (EPPM), expands on previous approaches in three ways: (a) by explaining why fear appeals fail; (b) by re‐incorporating fear as a central variable; and (c) by specifying the relationship between threat and efficacy in propositional forms Specific propositions are given to guide future research

Spontaneous Hypercholesterolemia and Arterial Lesions in Mice Lacking Apolipoprotein E

Abstract: Apolipoprotein E (apoE) is a ligand for receptors that clear remnants of chylomicrons and very low density lipoproteins Lack of apoE is, therefore, expected to cause accumulation in plasma of cholesterol-rich remnants whose prolonged circulation should be atherogenic ApoE-deficient mice generated by gene targeting were used to test this hypothesis and to make a mouse model for spontaneous atherosclerosis The mutant mice had five times normal plasma cholesterol, and developed foam cell-rich depositions in their proximal aortas by age 3 months These spontaneous lesions progressed and caused severe occlusion of the coronary artery ostium by 8 months The severe yet viable phenotype of the mutants should make them valuable for investigating genetic and environmental factors that modify the atherogenic process

Creative Cognition: Theory, Research, and Applications

Abstract: Part 1 Introduction to creative cognition: overview the goals of creative cognition demystification of creativity previous approaches to creativity scope of creative cognition. Part 2 Theoretical and methodological considerations: a general model structuring creative opportunities experimental procedures and controls motivational factors evaluating creative products general issues in creativity assessment. Part 3 Creative visualization: mental synthesis and transformation emergent features in mental images creative visual discoveries externalizing the creative process. Part 4 Creative invention: a paradigm for invention preinventive forms creative refinement.

Prognostic factors for local recurrence, metastasis, and survival rates in squamous cell carcinoma of the skin, ear, and lip : implications for treatment modality selection

Abstract: We reviewed all studies since 1940 on the prognosis of squamous cell carcinoma (SCC) of the skin and lip. The following variables are correlated with local recurrence and metastatic rates: (1) treatment modality, (2) prior treatment, (3) location, (4) size, (5) depth, (6) histologic differentiation, (7) histologic evidence of perineural involvement, (8) precipitating factors other than ultraviolet light, and (9) host immunosuppression. Local recurrences occur less frequently when SCC is treated by Mohs micrographic surgery. This local recurrence rate differential in favor of Mohs micrographic surgery holds true for primary SCC of the skin and lip (3.1% vs 10.9%), for ear SCC (5.3% vs 18.7%), for locally recurrent (previously treated) SCC (10% vs 23.3%), for SCC with perineural involvement (0% Ys 47%), for SCC of size greater than 2 cm (25.2% vs 41.7%), and for SCC that is poorly differentiated (32.6% vs 53.6%).

Support seeking and support giving within couples in an anxiety-provoking situation: The role of attachment styles.

Abstract: This study examined how adult attachment styles moderate spontaneous behavior between dating couples when 1 member of the dyad is confronted with an anxiety-provoking situation Eighty-three dating couples were unobtrusively videotaped for 5 min in a waiting room while the woman waited to participate in an "activity" known to provoke anxiety in most people Independent observers then evaluated each partner's behavior on several dimensions Results revealed that persons with more secure attachment styles behaved differently than persons with more avoidant styles in terms of physical contact, supportive comments, and efforts to seek and give emotional support Findings are discussed in the context of theory and research on attachment Recently, a growing number of researchers have begun to explore how different attachment styles influence what transpires within adult relationships (eg, Collins & Read, 1990; Feeney & Noller, 1990; Hazan & Shaver, 1987; Levy & Davis, 1988; Simpson, 1990) Virtually all of this research has been guided by Bowlby's (1969,1973,1980) attachment theory Bowlby sought to understand why infants forge strong emotional bonds to their primary caregivers and why they often exhibit pronounced anxiety and distress when they are separated from them Adopting an evolutionary- ethological perspective, he argued that the specific sequence of behavioral and emotional reactions associated with separation—protest, despair, and detachment—might reflect the operation of an innate attachment system designed to promote close physical contact between vulnerable infants and their primary caregivers By maintaining close proximity with their caregivers, infants would be more likely to survive, to reproduce, and ultimately to pass attachment and proximity-seeking propensities on to subsequent generations Although the tendency to seek proximity seems to be universal in infants, its development and elaboration over time is sensitive to specific environmental conditions, especially transactions between the infant and his or her primary caregiver Past empirical research has examined characteristic patterns of attachment behavior that develop between infants and their caregivers that signify different types of infant-caregiver relationships Using the Strange Situation paradigm, Ainsworth, Blehar, Waters, and Wall (1978) identified three primary patterns

Analysis of gene expression in single live neurons.

Abstract: We present here a method for broadly characterizing single cells at the molecular level beyond the more common morphological and transmitter/receptor classifications. The RNA from defined single cells is amplified by microinjecting primer, nucleotides, and enzyme into acutely dissociated cells from a defined region of rat brain. Further processing yields amplified antisense RNA. A second round of amplification results in greater than 10(6)-fold amplification of the original starting material, which is adequate for analysis--e.g., use as a probe, making of cDNA libraries, etc. We demonstrate this method by constructing expression profiles of single live cells from rat hippocampus. This profiling suggests that cells that appear to be morphologically similar may show marked differences in patterns of expression. In addition, we characterize several mRNAs from a single cell, some of which were previously undescribed, perhaps due to "rarity" when averaged over many cell types. Electrophysiological analysis coupled with molecular biology within the same cell will facilitate a better understanding of how changes at the molecular level are manifested in functional properties. This approach should be applicable to a wide variety of studies, including development, mutant models, aging, and neurodegenerative disease.

The Structure of Wages

Abstract: Although surveys show that traditional orderings of average wage—i.e., higher earnings with higher schooling and concave age-wage profiles—have not changed during the past three decades, the actual size of the wage differentials measured by education or by work experience has varied from peak to trough by a factor of two-to-one. The patterns are not monotone, but there is a trend toward increased skill premiums. We first examine the structure of wages among white men distinguished by age and schooling for the period from 1963 to 1989. We then compare shifts in the distribution of wages and employment among the age x schooling categories to show in reference to a stable demand structure that employment alone cannot account for observed changes in relative wages. Finally, we describe the characteristics required of candidate demand shifters and offer examples using linear trend, business cycle shocks, and recent patterns of deficits in international trade.

Wavelets: A Tutorial in Theory and Applications

Abstract: Orthogonal wavelets daubechies' scaling function on (0.3), D. Pollen wavelet matrices and the representation of discrete functions, P.N. Heller, et al wavelets and generalized functions, G.G. Walter semi-orthogonal and nonorthogonal wavelets cardinal spline interpolation and teh block spin construction of wavelets, G. Battle polynomial splines and wavelets - a signal processing perspective, M. Unser and A. Aldroubi biorthogonal wavelets, A. Cohen nonorthogonal multiresolution analysis using wavelets, J.C. Feauveau wavelet-like local bases wavelets and other bases for fast numerical linear algebra, B.K. Alpert wavelets with boundary conditions on the interval, P. Aushcer local sine and cosine bases of coifman and meyer and the construction of smooth wae-lets, P. Auscher, et al some elementary properties of multiresolution analysis of L2 (Rn), W.R. Madych multi-dimensional two-scale dilation equations, M.A. Berger and Y. Wang multivariate wavelets short-time fourier and window-radon transforms, J. Stockler gabor wavelets and the heisenberg group, H.G. Feichtinger and K. Grochenig gabor expansions and short time fourier transform from the group theoetical point of view windowed radon transforms, analytic signals and the wave equation theory of sampling and interpolation, G. Kaiser and R.F. Streater irregular sampling and frames, J.J. Benedetto families of wavelet tranforms in connections with Shannon's sampling theory and the gabor tranform, A.Aldroubi and M. Unser wavelets in H2(R), K. Seip sampling, interpolation and phase space density applications to numerical analysis and signal processing orthonormal wave-lets, analysis of operators and applications to numerical analysis, S. Jaffard and Ph. Laurencot wavelet transforms and filter banks, R.A. Gopinath and C.S. Burrus second generation compact image coding with wavelets, J. Froment and S. Mallat acoustic signal compression with wavelet packets, M.V. Wickerhauser.

The Nature of the Metal-Metal Bond in Bimetallic Surfaces

Abstract: The formation of a surface metal-metal bond can produce large perturbations in the electronic, chemical, and catalytic properties of a metal. Recent studies indicate that charge transfer is an important component in surface metal-metal bonds that involve dissimilar elements. The larger the charge transfer, the stronger the cohesive energy of the bimetallic bond. On a surface, the formation of a heteronuclear metal-metal bond induces a flow of electron density toward the element with the larger fraction of empty states in its valence band. This behavior is completely contrary to that observed in bulk alloys, indicating that the nature of a heteronuclear metal-metal bond depends strongly on the structural geometry of the bimetallic system.

Subcutaneous low-molecular-weight heparin compared with continuous intravenous heparin in the treatment of proximal-vein thrombosis.

Abstract: Background. Low-molecular-weight heparin has a high bioavailability and a prolonged half-life in comparison with conventional unfractionated heparin. Limited data are available for low-molecular-weight heparin as compared with unfractionated heparin for the treatment of deep-vein thrombosis. Methods. In a multicenter, double-blind clinical trial, we compared fixed-dose subcutaneous low-molecular-weight heparin given once daily with adjusted-dose intravenous heparin given by continuous infusion for the initial treatment of patients with proximal-vein thrombosis, using objective documentation of clinical outcomes. Results. Six of 213 patients who received low-molecular-weight heparin (2.8 percent) and 15 of 219 patients who received intravenous heparin (6.9 percent) had new episodes of venous thromboembolism (P = 0.07; 95 percent confidence interval for the difference, 0.02 percent to 8.1 percent). Major bleeding associated with initial therapy occurred in 1 patient receiving low-molecular-weight h...

Cooperative Versus Competitive Structures in Related and Unrelated Diversified Firms

Abstract: Herein we argue that different diversification strategies are associated with different sets of economic benefits. Firms that have diversified into related areas can realize benefits from economies of scope, while those that have diversified into unrelated areas can realize benefits from efficient internal governance mechanisms. We hypothesize that distinctly different internal organizational arrangements are required to realize these different benefits. Firms attempting to realize economies of scope need organizational arrangements that stress cooperation between business units. Firms attempting to realize economic benefits from efficient internal governance need organizational arrangements that stress competition between business units. If a diversified firm is to achieve high performance it must establish an appropriate fit between its diversification strategy on the one hand, and its organizational structure and control systems on the other. We test this thesis on 184 Fortune 1000 firms that participated in a survey of organizational arrangements. The results indicate that the appropriate fit between strategy, structure, and control systems is associated with superior performance. Firms attempting to realize economies of scope perform better if their organizational arrangements stress cooperation between business units, while firms attempting to realize economic benefits from efficient internal governance perform better if their organizational arrangements stress competition between business units.

Partial denaturation of transthyretin is sufficient for amyloid fibril formation in vitro

Abstract: Amyloid diseases are caused by the self-assembly of a given protein into an insoluble cross-beta-sheet quaternary structural form which is pathogenic. An understanding of the biochemical mechanism of amyloid fibril formation should prove useful in understanding amyloid disease. Toward this end, a procedure for the conversion of the amyloidogenic protein transthyretin into amyloid fibrils under conditions which mimic the acidic environment of a lysosome has been developed. Association of a structured transthyretin denaturation intermediate is sufficient for amyloid fibril formation in vitro. The rate of fibril formation is pH dependent with significant rates being observed at pHs accessible within the lysosome (3.6-4.8). Far-UV CD spectroscopic studies suggest that transthyretin retains its secondary structural features at pHs where fibrils are formed. Near-UV CD studies demonstrate that transthyretin has retained the majority of its tertiary structure during fibril formation as well. Near-UV CD analysis in combination with glutaraldehyde cross-linking studies suggests that a pH-mediated tetramer to monomer transition is operative in the pH range where fibril formation occurs. The rate of fibril formation decreases markedly at pHs below pH 3.6, consistent with denaturation to a monomeric TTR intermediate which has lost its native tertiary structure and capability to form fibrils. It is difficult to specify with certainty which quaternary structural form of transthyretin is the amyloidogenic intermediate at this time. These difficulties arise because the maximal rate of fibril formation occurs at pH 3.6 where tetramer, traces of dimer, and significant amounts of monomer are observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of antioxidant enzymes.

Abstract: Free radicals generated by a partial reduction of O2 pose a serious hazard to tissues and vital organs, especially membrane lipids, connective tissues, and the nucleic acids of cells. For protection, enzymes have evolved that specifically attack O2-, hydrogen, and organic peroxides, and repair any damage incurred to DNA. With few exceptions, antioxidant enzymes are found in all aerobic and aerotolerant anaerobic organisms. Logic assumes that a basal level of antioxidant enzyme activity is maintained at all times. This may be true. Yet cells must have ways to amplify antioxidant enzyme activity to counter sudden increases in oxygen metabolites. The full details of that regulation are slowly coming to light. Bacteria possess a series of elaborate and interacting genes that can sense specific increases in intracellular H2O2 and O2-. In higher organisms, hormones and metal ion cofactors impose pre- and posttranslational control over the genetic expression of antioxidant enzymes. Furthermore, aging, cellular differentiation, and organ specificity must also be factored into the final equation in higher organisms. This review will discuss some of the more recent findings relevant to antioxidant enzyme regulation in bacteria and higher organisms.

Academic Dishonesty: Prevalence, Determinants, Techniques, and Punishments

Abstract: Data from more than 6,000 students regarding the prevalence, causes, techniques, faculty and institutional responsibility, deterrent measures, and punishment dimensions of academic dishonesty are presented.

Theoretical and experimental development of 10 and 35 GHz rectennas

Abstract: A 35-GHz rectenna has been developed with 39% conversion efficiency. The rectenna uses a microstrip dipole antenna and a commercially available mixer diode. Over 60% conversion efficiency was demonstrated using this diode at 10 GHz. A theoretical analysis was derived to predict the performance of the rectenna. The analysis is a useful tool for device and circuit design. The theoretical and experimental results should have many applications in microwave power transmission and detection. >

Recreation Specialization: Re-conceptualization from a Social Worlds Perspective

Abstract: This paper initiated development of a theory of recreation specialization from a social worlds perspective and provided empirical testing for some of the stated propositions. Recreation specializat...

Sociosexuality and Romantic Partner Choice

Abstract: In three studies, we explored how individual differences in sociosexual orientation systematically relate to the types of attributes people prefer in romantic partners. In Investigation 1, individuals rated the importance of 15 partner attributes. Two factors emerged: personal/parenting qualities and attractiveness/social visibility. Individuals who possessed a restricted sociosexual orientation rated attributes that loaded highly on the former factor as being more important than those that loaded highly on the second one, whereas the reverse was true for unrestricted individuals. In Investigation 2, individuals evaluated two prospective romantic partners, one who was described as highly attractive and socially visible but less desirable in terms of personal/parenting qualities and one who had the opposite set of attributes. Unrestricted individuals tended to select the former partner, whereas restricted individuals chose the latter one. Investigation 3 examined the attributes actually possessed by their romantic partners. Unrestricted individuals were dating partners who were more socially visible and attractive, whereas restricted individuals were dating partners who were more responsible, faithful/loyal, and affectionate. Results are discussed in terms of an evolutionary model that links sociosexuality to mate selection.

Link between iron and sulphur cycles suggested by detection of Fe(n) in remote marine aerosols

Abstract: IRON is essential to the growth of organisms, and iron derived from the atmosphere may be the limiting nutrient for primary productivity in some oceanic regions1–6. Aeolian mineral dust is the chief source of marine iron in many areas1–3,5,7, but there is little information on the chemical form of the iron in this dust. Here we report that Fe(n) contributed 56±32% of the total iron in marine aerosol samples collected over the central North Pacific and 49 + 15% at Barbados. We suggest that the key reaction that produces Fe(n), and hence increases the solubility of marine aerosol iron in sea water, is [Fe(in)(OH)(H2O)5]2+ + H2O^ [Fe(n)(H2O)6]2+ + OH- (refs 8–10). The presence of Fe(n) in remote marine aerosols suggests that the OH radical has been produced in these heterogeneous reactions. From consideration of both the marine biological production of dimethylsulphide and the subsequent oxidation of reduced forms of sulphur in the atmosphere, we propose that the iron and sulphur cycles in both the atmosphere and the ocean may be closely coupled.

Wavelets on a Bounded Interval

Abstract: The aim of this paper is to present two different approaches to the study of multiresolution analysis and wavelets on a bounded interval. Recently, Meyer obtained orthonormal wavelets on a bounded interval by restricting Daubechies’ scaling functions and wavelets to [0, 1] and applying the Gram-Schmidt procedure to orthonormalize the restrictions. Our own approach — presented in the second part of the paper — is based on the semi-orthogonal Chui-Wang spline-wavelets. In this case we no longer have orthogonality in one scale, but there are explicit formulae for these wavelets.

Extrinsic and Intrinsic Origins of Perceived Social Loafing in Organizations

Abstract: It was hypothesized and found that task visibility and intrinsic task involvement would each be negatively associated with “social loafing” in an ongoing organization. Individuals engaged in social...