Showing papers by "University of Houston published in 2003"

Completely Bounded Maps and Operator Algebras

Abstract: In this book, first published in 2003, the reader is provided with a tour of the principal results and ideas in the theories of completely positive maps, completely bounded maps, dilation theory, operator spaces and operator algebras, together with some of their main applications. The author assumes only that the reader has a basic background in functional analysis, and the presentation is self-contained and paced appropriately for graduate students new to the subject. Experts will also want this book for their library since the author illustrates the power of methods he has developed with new and simpler proofs of some of the major results in the area, many of which have not appeared earlier in the literature. An indispensable introduction to the theory of operator spaces for all who want to know more.

Principles of crystal nucleation and growth

Abstract: In the most general sense, biomineralization is a process by which organisms produce materials solutions for their own functional requirements. Because so many biomineral products are derived from an initial solution phase and are either completely crystalline or include crystalline components, an understanding of the physical principles of crystallization from solutions is an important tool for students of biomineralization. However, crystal growth is a science of great breadth and depth, about which many extensive texts have been written. In addition, there are already other thorough reviews that specifically address the crystal growth field of study as it relates to biomineral formation. Consequently, the goals of this chapter are both modest and specific. It is intended to provide: 1) a simple narrative explaining the physical principles behind crystallization for those who are completely new to the topic, 2) a few basic equations governing nucleation and growth for those who wish to apply those principles—at least in a semi-quantitative fashion—to experimental observations of mineralization, and 3) an overview of some recent molecular-scale studies that have revealed new insights into the control of crystal growth by small molecules, both organic and inorganic. This last topic gets to the heart of what makes crystallization in biological systems unique. Every day, many tons of crystals are produced synthetically in non-biological processes, but by-and-large, the degree of control over nucleation and growth achieved by deterministic additions of growth modifiers or the presence of a controlling matrix is very minor. More commonly, crystal growers view modifying agents as unwanted impurities and work extremely hard to eliminate them from the starting materials. Indeed, the degree to which living organisms are able to control the crystallization process is most striking when contrasted to the products of such synthetic crystallization processes. This contrast applies to both the compositional differences that …

Accrued Earnings and Growth: Implications for Future Profitability and Market Mispricing

Abstract: Prior research reveals that the accrual component of profitability is less persistent than the cash flow component, and that investors fail to fully appreciate their differing implications for future profitability (Sloan 1996). However, accruals are a component of growth in net operating assets as well as a component of profitability. Just as we can disaggregate profitability into accruals and cash flows from operations, we can disaggregate growth in net operating assets into accruals and growth in long‐term net operating assets. We find that, after controlling for current profitability, both components of growth in net operating assets—accruals and growth in long‐term net operating assets—have equivalent negative associations with one‐year‐ahead return on assets. This result is consistent with conservative accounting and diminishing marginal returns on investments. We also find that, after controlling for current profitability, the market appears to equivalently overvalue accruals and growth in long‐term...

Regulation of Motivation: Evaluating an Underemphasized Aspect of Self-Regulated Learning.

Abstract: Self-regulated learning is often described as a function of students' motivation, cognitive strategy use, and metacognition. The purpose of this article is to emphasize regulation of motivation as another important aspect of self-regulated learning. To achieve this goal, a specific conceptual understanding of regulation of motivation is proposed and used to clarify theoretical distinctions between this process and motivation, metacognition, and volition. In addition, the diverse nature of this regulatory activity is established by reviewing evidence showing students' use of several specific strategies for the regulation of motivation. The importance of this process is highlighted by discussing links between these regulatory strategies and indicators of students' motivation, cognitive engagement, and achievement. Finally, a guide for additional research related to the theoretical definition, measurement, development and instruction of strategies for regulating motivation is identified.

Antibiotic resistance among gram-negative bacilli in US intensive care units: implications for fluoroquinolone use.

Abstract: ContextPrevious surveillance studies have documented increasing rates of antimicrobial resistance in US intensive care units (ICUs) in the early 1990s.ObjectivesTo assess national rates of antimicrobial resistance among gram-negative aerobic isolates recovered from ICU patients and to compare these rates to antimicrobial use.Design and SettingParticipating institutions, representing a total of 43 US states plus the District of Columbia, provided antibiotic susceptibility results for 35 790 nonduplicate gram-negative aerobic isolates recovered from ICU patients between 1994 and 2000.Main Outcome MeasuresEach institution tested approximately 100 consecutive gram-negative aerobic isolates recovered from ICU patients. Organisms were identified to the species level. Susceptibility tests were performed, and national fluoroquinolone consumption data were obtained.ResultsThe activity of most antimicrobial agents against gram-negative aerobic isolates showed an absolute decrease of 6% or less over the study period. The overall susceptibility to ciprofloxacin decreased steadily from 86% in 1994 to 76% in 2000 and was significantly associated with increased national use of fluoroquinolones.ConclusionsThis study documents the increasing incidence of ciprofloxacin resistance among gram-negative bacilli that has occurred coincident with increased use of fluoroquinolones. More judicious use of fluoroquinolones will be necessary to limit this downward trend.

Evidence on the Joint Determination of Audit and Non‐Audit Fees

Abstract: In this study we investigate whether the characteristics of clients, auditors, and the auditor-client relationship simultaneously determine audit and non-audit fees. As done in prior studies, we maintain that fees proxy for the level of service provided and follow the physical flow of knowledge. Estimating single-equation models of audit and non-audit fee models, we confirm prior findings of an association between audit and non-audit fees. Studies conclude that such evidence is consistent with knowledge spillovers between the two services. However, we document empirically that audit and non-audit fees are simultaneously determined. Because the data indicate audit and non-audit fees are jointly determined, we then investigate whether previously documented associations between audit and non-audit fees are the result of biased estimation induced by using endogenous variables in single-equation models. In contrast to results from single-equation estimations, we find no association between audit and non-audit fees using a simultaneous specification of the fee system, suggesting that single-equation estimations suffer from simultaneous-equations bias. In sum, the findings are not consistent with the existence of economies of scope from the joint performance of audit and non-audit services after controlling for the joint behavior of audit and non-audit fees. Given the ongoing debate over the level of allowed non-audit services by auditors, the argument for the joint provision of audit and non-audit services is less justified than if joint-supply benefits had been documented.

Phenotypic plasticity and interactions among plants

Abstract: We know a great deal about the plastic responses of plant phenotypes to the abiotic and biotic environment, but very little about the consequences of phenotypic plas- ticity for plant communities. In other words, we know that plant traits can vary widely for a given genotype, but we know little about the importance of trait-mediated interactions (TMI) among plants. Here, we discuss three major factors that affect the expression of phenotypic plasticity: variation in the abiotic environment, variation in the presence or identity of neighbors, and variation in herbivory. We consider how plastic responses to these factors might affect interactions among plants. Plastic responses to the abiotic en- vironment have important consequences for conditionality in competitive effects, to the point of causing shifts from competitive to facilitative interactions. Because plants show a high degree of plasticity in response to neighbors, and even to the specific identify of neighbors, phenotypic plasticity may allow species to adjust to the composition of their communities, promoting coexistence and community diversity. Likewise, plastic responses to consumers may have various and counterintuitive consequences: induction of plant re- sistance, compensatory growth, and increased resource uptake may affect interactions among plants in ways that cannot be predicted simply by considering biomass lost to consumers. What little we know about TMI among plants suggests that they should not be ignored in plant community theory. Although work to date on the community consequences of phenotypic plasticity has been hampered by experimental constraints, new approaches such as manipulating phenotypes by using signals instead of actual environmental conditions and the use of transgenic plants should allow us to rapidly expand our understanding of the community consequences of plant plasticity.

A Randomized Clinical Trial of Progressive Addition Lenses versus Single Vision Lenses on the Progression of Myopia in Children

Abstract: Purpose The purpose of the Correction of Myopia Evaluation Trial (COMET) was to evaluate the effect of progressive addition lenses (PALs) compared with single vision lenses (SVLs) on the progression of juvenile-onset myopia. Methods COMET enrolled 469 children (ages 6-11 years) with myopia between -1.25 and -4.50 D spherical equivalent. The children were recruited at four colleges of optometry in the United States and were ethnically diverse. They were randomly assigned to receive either PALs with a +2.00 addition (n = 235) or SVLs (n = 234), the conventional spectacle treatment for myopia, and were followed for 3 years. The primary outcome measure was progression of myopia, as determined by autorefraction after cycloplegia with 2 drops of 1% tropicamide at each annual visit. The secondary outcome measure was change in axial length of the eyes, as assessed by A-scan ultrasonography. Child-based analyses (i.e., the mean of the two eyes) were used. Results were adjusted for important covariates, by using multiple linear regression. Results Of the 469 children (mean age at baseline, 9.3 +/- 1.3 years), 462 (98.5%) completed the 3-year visit. Mean (+/-SE) 3-year increases in myopia (spherical equivalent) were -1.28 +/- 0.06 D in the PAL group and -1.48 +/- 0.06 D in the SVL group. The 3-year difference in progression of 0.20 +/- 0.08 D between the two groups was statistically significant (P = 0.004). The treatment effect was observed primarily in the first year. The number of prescription changes differed significantly by treatment group only in the first year. At 6 months, 17% of the PAL group versus 30% of the SVL group needed a prescription change (P = 0.0007), and, at 1 year, 43% of the PAL group versus 59% of the SVL group required a prescription change (P = 0.002). Interaction analyses identified a significantly larger treatment effect of PALs in children with lower versus higher baseline accommodative response at near (P = 0.03) and with lower versus higher baseline myopia (P = 0.04). Mean (+/- SE) increases in the axial length of eyes of children in the PAL and SVL groups, respectively, were: 0.64 +/- 0.02 mm and 0.75 +/- 0.02 mm, with a statistically significant 3-year mean difference of 0.11 +/- 0.03 mm (P = 0.0002). Mean changes in axial length correlated with those in refractive error (r = 0.86 for PAL and 0.89 for SVL). Conclusions Use of PALs compared with SVLs slowed the progression of myopia in COMET children by a small, statistically significant amount only during the first year. The size of the treatment effect remained similar and significant for the next 2 years. The results provide some support for the COMET rationale-that is, a role for defocus in progression of myopia. The small magnitude of the effect does not warrant a change in clinical practice.

Understanding Procrastination from a Self-Regulated Learning Perspective.

Abstract: Academic procrastination includes failing to perform an activity within the desired time frame or postponing until the last minute activities one ultimately intends to complete. As such, high levels of procrastination appear inconsistent with the behaviors typically attributed to self-regulated learners, However, research exploring the relation between these 2 constructs is lacking. Two studies (N = 168 and N = 152) examining procrastination and its relation to several key components of self-regulated learning using self-report surveys are reported here. Results indicate that procrastination was related to college students' self-efficacy and work-avoidant goal orientation and, to a lesser extent, their use of metacognitive strategies. Findings are discussed with regard to prior research on self-regulated learning and procrastination and to future research. (PsycINFO Database Record (c) 2016 APA, all rights reserved)

Leadership in research and development organizations: A literature review and conceptual framework

Abstract: We present a conceptual framework and review the empirical literature on leadership in research and development (R&D) organizations. Findings of studies reviewed suggest that transformational project leaders who communicate an inspirational vision and provide intellectual stimulation and leaders who develop a high-quality leader–member exchange (LMX) relationship with project members are associated with project success. Boundary-spanning activity and championing by the leader are also found to be important factors for project success. The review also suggests that a number of moderators and contextual variables such as project group membership and rate of technological change may make leadership in R&D organizations different from that in operating organizations. Propositions for future research are suggested.

Cities, regions and the decline of transport costs*

Abstract: The theoretical framework of urban and regional economics is built on transportation costs for manufactured goods. But over the twentieth century, the costs of moving these goods have declined by over 90% in real terms, and there is little reason to doubt that this decline will continue. Moreover, technological change has eliminated the importance of fixed infrastructure transport (rail and water) that played a critical role in creating natural urban centres. In this article, we document this decline and explore several simple implications of a world where it is essentially free to move goods, but expensive to move people. We find empirical support for these implications.

Trust and the unintended effects of behavior control in virtual teams

Abstract: This article reports the findings of a longitudinal study of temporary virtual teams and explores the role of behavior control on trust decline. We conducted an experiment involving 51 temporary virtual teams. Half of the teams were required to comply with behavior control mechanisms traditionally used in colocated teams. Their counterparts were allowed to self-direct. Our analysis shows that the behavior control mechanisms typically used in traditional teams have a significant negative effect on trust in virtual teams. In-depth analysis of the communication logs of selected teams reveals that trust decline in virtual teams is rooted in instances of reneging and incongruence. Behavior control mechanisms increase vigilance and make instances when individuals perceive team members to have failed to uphold their obligations (i.e., reneging and incongruence) salient. Heightened vigilance and salience increase the likelihood that team members' failure to fulfill their obligations will be detected, thus contributing to trust decline.

Interface Dipoles Arising from Self-Assembled Monolayers on Gold: UV−Photoemission Studies of Alkanethiols and Partially Fluorinated Alkanethiols

Abstract: Gold surfaces modified with C3−C18-alkanethiols (CH3(CH2)X-1SH; HXSH; x = 3, 8, 12, 16, 18) and C16-alkanethiols, fluorinated at the outer 1, 2, 4, and 10 methylene positions (CF3(CF2)Y-1(CH2)XSH; FyHxSH; y = 1, x = 15; y = 2, x = 14; y = 4, x = 12; y = 10, x = 6) were characterized by He(I) UV-photoelectron spectroscopy (UPS). (Detailed X-ray photoelectron spectroscopic characterization of the partially fluorinated thin films is given in the Supporting Information). Long incubation times of the gold surface with the alkanethiol solutions lead to compact monolayer films for all of the alkanethiols, as indicated by the exponential decrease in emission intensity versus alkyl chain length for both the gold Fermi edge (UPS data), and by a parallel decrease in Au(4f) photoemission intensity using X-ray photoelectron spectroscopy. Changes in the effective work function of these surfaces due to the presence of significant interfacial dipoles are observed (i) as alkyl chain length is increased, and (ii) as the fr...

Combining second-order Jahn-Teller distorted cations to create highly efficient SHG materials: synthesis, characterization, and NLO properties of BaTeM2O9 (M = Mo6+ or W6+).

Abstract: Two new oxides, BaTeMo2O9 and BaTeW2O9, have been synthesized, by standard solid-state techniques, that have strong SHG intensities of approximately 600 x SiO2, on the order of LiNbO3. Both materials contain cations susceptible to second-order Jahn-Teller (SOJT) distortions, resulting in asymmetric coordination environments. The SOJT distortion polarizes the M6+-O and Te4+-O bonds. Equally importantly, these polarizations constructively add, resulting in the large SHG responses. Powder SHG measurements on BaTeM2O9 (M = Mo6+ or W6+) indicated that both materials are phase-matchable and have a deffexp of 28 and 22 pm/V, respectively. Using bond hyperpolarizability values (beta's) of 130 x 10-40 and 305 x 10-40 m4/V for Te4+-O and Mo6+-O respectively, we calculate a deffcalc of 20pm/V for BaTeMo2O9. In addition, through the powder SHG measurements, we are able to give a more reasonable value for beta(W6+-O), 230 x 10-40 m4/V. This value is consistent with the smaller polarizability and magnitude of the intra-octahedral distortion of W6+ compared with Mo6+.

Mesozoic and Cenozoic tectonic evolution of the Shiquanhe area of western Tibet

Abstract: [1] In the Shiquanhe area of far-western Tibet, mid-Cretaceous strata lie unconformable on ophiolitic melange and Jurassic flysch associated with the Bangong-Nujiang suture zone. On the basis of our mapping and geochronologic studies, we suggest that these Cretaceous strata were shortened by >57% over a north south distance of 50 km during Late Cretaceous-early Tertiary time. The Late Cretaceous Narangjiapo thrust placed Permian strata >20 km over ophiolitic melange and Cretaceous strata. North of the Narangjiapo thrust, >40 km of shortening was accommodated by the Late Cretaceous-early Tertiary south directed Jaggang thrust system that involves Jurassic flysch and Cretaceous strata, and roots into a decollement within ophiolitic melange. The most recent shortening was accommodated to the south of the Narangjiapo thrust, along the north dipping Shiquanhe thrust. The Shiquanhe thrust cuts flat-lying 22.6 ± 0.3 Ma volcanic rocks and underlying folded, Tertiary nonmarine strata in its footwall and was likely active during slip along the Oligocene Gangdese thrust system of southern Tibet. Ophiolitic melange and structurally overlying Jurassic flysch near Shiquanhe are interpreted to represent remnants of a subduction-accretion complex and forearc basin, respectively, that were obducted southward onto the margin of the Lhasa terrane during Late Jurassic-Early Cretaceous closure of the Bangong-Nujiang Ocean. Subsequent imbrication of the obducted sheet could have produced the two east-west trending belts of ophiolitic melanges, separated by ∼100 km, in western Tibet. Late Cretaceous-early Tertiary thin-skinned shortening may have been accommodated in the deeper crust by northward underthrusting and duplexing of Lhasa terrane rocks beneath the obducted ophiolitic melange and the Qiangtang terrane to the north.

Refractive Error and Visual Impairment in African Children in South Africa

Abstract: Purpose To assess the prevalence of refractive error and visual impairment in school-aged African children in South Africa. Methods Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age in the Durban area. From January to August 2002, children in 35 clusters were enumerated through a door-to-door survey and examined in temporary facilities. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. In nine clusters, children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance. Results A total of 5599 children living in 2712 households were enumerated, and 4890 (87.3%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye was 1.4%, 1.2%, and 0.32%, respectively. Refractive error was the cause in 63.6% of the 191 eyes with reduced vision, amblyopia in 7.3%, retinal disorders in 9.9%, corneal opacity in 3.7%, other causes in 3.1%, and unexplained causes in the remaining 12.0%. Exterior and anterior segment abnormalities were observed in 528 (10.8%) children, mainly corneal and conjunctival. Myopia (at least -0.50 D) in one or both eyes was present in 2.9% of children when measured with retinoscopy and in 4.0% measured with autorefraction. Beginning with an upward trend at age 14, myopia prevalence with autorefraction reached 9.6% at age 15. Myopia was also associated with increased parental education. Hyperopia (+2.00 D or more) in at least one eye was present in 1.8% of children when measured with retinoscopy and in 2.6% measured with autorefraction, with no significant predictors of hyperopia risk. Conclusions The prevalence of reduced vision is low in school-age African children, most of it because of uncorrected refractive error. The high prevalence of corneal and other anterior segment abnormalities is a reflection of the inadequacy of primary eye care services in this area.

Interaction between aberrations to improve or reduce visual performance.

Abstract: Purpose To investigate how pairs of Zernike modes interact to increase or decrease visual acuity. Setting Visual Optics Institute, College of Optometry, University of Houston, Houston, Texas, USA. Methods Subjects read aberrated and unaberrated visual acuity charts 3 times. Each aberrated chart was produced by convolving an aberrated point-spread function with an unaberrated acuity chart. Point-spread functions were defined by 4 pairs of Zernike modes. For each pair, 9 combinations were used, ranging from all aberration being loaded into the first mode to all aberration being loaded into the second mode. The root mean square (RMS) wavefront error always totaled 0.25 μm (6.0 mm pupil), a level similar to the aberration induced by traditional flying small-spot laser refractive surgeries. Results For all conditions (except the unaberrated charts), visual acuity decreased. Acuity varied significantly depending on which modes were mixed and the relative contribution of each mode. Modes 2 radial orders apart and having the same sign and angular frequency tended to combine to increase visual acuity. Modes within the same radial order tended to combine to decrease acuity. Conclusions For low levels of aberration, the RMS wavefront error is not a good predictor of visual acuity. Clinically, it is important to define how aberrations interact to optimize visual performance. New metrics of optical/neural performance that correlate better with clinical measures of visual performance need to be adopted or developed, as well as new clinically viable measures of visual performance that are sensitive to subtle changes in optical performance.

Inverse scattering series and seismic exploration

Abstract: This paper presents an overview and a detailed description of the key logic steps and mathematical-physics framework behind the development of practical algorithms for seismic exploration derived from the inverse scattering series. There are both significant symmetries and critical subtle differences between the forward scattering series construction and the inverse scattering series processing of seismic events. These similarities and differences help explain the efficiency and effectiveness of different inversion objectives. The inverse series performs all of the tasks associated with inversion using the entire wavefield recorded on the measurement surface as input. However, certain terms in the series act as though only one specific task, and no other task, existed. When isolated, these terms constitute a task-specific subseries. We present both the rationale for seeking and methods of identifying uncoupled task-specific subseries that accomplish: (1) free-surface multiple removal; (2) internal multiple attenuation; (3) imaging primaries at depth; and (4) inverting for earth material properties. A combination of forward series analogues and physical intuition is employed to locate those subseries. We show that the sum of the four task-specific subseries does not correspond to the original inverse series since terms with coupled tasks are never considered or computed. Isolated tasks are accomplished sequentially and, after each is achieved, the problem is restarted as though that isolated task had never existed. This strategy avoids choosing portions of the series, at any stage, that correspond to a combination of tasks, i.e., no terms corresponding to coupled tasks are ever computed. This inversion in stages provides a tremendous practical advantage. The achievement of a task is a form of useful information exploited in the redefined and restarted problem; and the latter represents a critically important step in the logic and overall strategy. The individual subseries are analysed and their strengths, limitations and prerequisites exemplified with analytic, numerical and field data examples.

Risk Sharing and Industrial Specialization: Regional and International Evidence

Abstract: We provide empirical evidence that risk sharing enhances specialization in production. To the best of our knowledge, this well-established and important theoretical proposition has not been tested before. Our empirical procedure is summarized as follows. First, we construct a measure of specialization in production, and calculate an index of specialization for each of the European Community (EC) and non-EC OECD countries, U.S. states, Canadian provinces, Japanese prefectures, Latin American countries, and regions of Italy, Spain, and the United Kingdom. Then, we estimate the degree of capital market integration (a measure of risk sharing) within each of these groups of regions: the EC countries, the non-EC OECD countries, the United States, Canada, Japan, Italy, Spain, and the United Kingdom (and rely on another author's estimate for Latin America). Finally, we perform a regression of the specialization index on the degree of risk sharing, controlling for relevant economic variables. We find a positive and significant relation between the degree of specialization of individual members of a group of countries, provinces, states, or prefectures, and the amount of risk that is shared within the group. We perform regressions using variables such as shareholder rights and the size of the financial sector (relative to GDP) as instruments for the amount of inter-regional risk sharing. These regressions confirm that risk sharing---facilitated by a favorable legal environment and a developed financial system---is a direct causal determinant of industrial specialization.

Origin of ocean island basalts: A new perspective from petrology, geochemistry, and mineral physics considerations

Abstract: Consideration of petrology, geochemistry, and mineral physics suggests that ancient subducted oceanic crusts cannot be the source materials supplying ocean island basalts (OIB). Melting of oceanic crusts cannot produce high-magnesian OIB lavas. Ancient oceanic crusts (>1 Ga) are isotopically too depleted to meet the required values of most OIB. Subducted oceanic crusts that have passed through subduction zone dehydration are likely to be depleted in water-soluble incompatible elements (e.g., Ba, Rb, Cs, U, K, Sr, Pb) relative to water-insoluble incompatible elements (e.g., Nb, Ta, Zr, Hf, Ti). Melting of residual crusts with such trace element composition cannot produce OIB. Oceanic crusts, if subducted into the lower mantle, will be >2% denser than the ambient mantle at shallow lower mantle depths. This negative buoyancy will impede return of the subducted oceanic crusts into the upper mantle. If subducted oceanic crusts melt at the base of the mantle, the resultant melts are even denser than the ambient peridotitic mantle, perhaps by as much as similar to15%. Neither in the solid state nor in melt form can bulk oceanic crusts subducted into the lower mantle return to upper mantle source regions of oceanic basalts. Deep portions of recycled oceanic lithosphere are important geochemical reservoirs hosting volatiles and incompatible elements as a result of metasomatism taking place at the interface between the low-velocity zone and the cooling and thickening oceanic lithosphere. These metasomatized and recycled deep portions of oceanic lithosphere are the most likely candidates for OIB sources in terms of petrology, geochemistry and mineral physics.

Assessing the Relative Informativeness and Permanence of Pro Forma Earnings and GAAP Operating Earnings

Abstract: This study investigates whether market participants perceive pro forma earnings to be more informative and more persistent than GAAP operating income by analyzing a sample of 1,149 actual pro forma press releases. We find that pro forma announcers report frequent GAAP losses and are mostly concentrated in the service and high-tech industries. Our analyses of short-window abnormal returns and revisions in analyst' one-quarter-ahead earnings forecasts indicate that pro forma earnings are more informative and more permanent than GAAP operating earnings. Our evidence suggests that market participants believe pro forma earnings are more representative of "core earnings" than GAAP operating income.

Transaction cost-enhanced entry mode choices and firm performance.

Abstract: According to transaction cost theory, firms select the international mode of entry that provides the most efficient form of governance. However, previous scholarship largely neglects the impact of transaction cost variables on entry mode choice and firm performance. In this study, we add transaction cost variables to a set of variables previously used to predict firm mode choice and performance. We theorize and find that firms selecting these ‘transaction cost-enhanced international entry modes’ perform better than firms using other modes of entry. Based on our results, we conclude that ‘enhanced’ transaction cost theory appears to be normative as well as descriptive with respect to international entry mode decisions. Copyright © 2003 John Wiley & Sons, Ltd.

Hypoxia-induced endocytosis of Na,K-ATPase in alveolar epithelial cells is mediated by mitochondrial reactive oxygen species and PKC-ζ

Abstract: During ascent to high altitude and pulmonary edema, the alveolar epithelial cells (AEC) are exposed to hypoxic conditions. Hypoxia inhibits alveolar fluid reabsorption and decreases Na,K-ATPase activity in AEC. We report here that exposure of AEC to hypoxia induced a time-dependent decrease of Na,K-ATPase activity and a parallel decrease in the number of Na,K-ATPase alpha(1) subunits at the basolateral membrane (BLM), without changing its total cell protein abundance. These effects were reversible upon reoxygenation and specific, because the plasma membrane protein GLUT1 did not decrease in response to hypoxia. Hypoxia caused an increase in mitochondrial reactive oxygen species (ROS) levels that was inhibited by antioxidants. Antioxidants prevented the hypoxia-mediated decrease in Na,K-ATPase activity and protein abundance at the BLM. Hypoxia-treated AEC deficient in mitochondrial DNA (rho(0) cells) did not have increased levels of ROS, nor was the Na,K-ATPase activity inhibited. Na,K-ATPase alpha(1) subunit was phosphorylated by PKC in hypoxia-treated AEC. In AEC treated with a PKC-zeta antagonist peptide or with the Na,K-ATPase alpha(1) subunit lacking the PKC phosphorylation site (Ser-18), hypoxia failed to decrease Na,K-ATPase abundance and function. Accordingly, we provide evidence that hypoxia decreases Na,K-ATPase activity in AEC by triggering its endocytosis through mitochondrial ROS and PKC-zeta-mediated phosphorylation of the Na,K-ATPase alpha(1) subunit.

Critical event prediction for proactive management in large-scale computer clusters

Abstract: As the complexity of distributed computing systems increases, systems management tasks require significantly higher levels of automation; examples include diagnosis and prediction based on real-time streams of computer events, setting alarms, and performing continuous monitoring The core of autonomic computing, a recently proposed initiative towards next-generation IT-systems capable of 'self-healing', is the ability to analyze data in real-time and to predict potential problems The goal is to avoid catastrophic failures through prompt execution of remedial actionsThis paper describes an attempt to build a proactive prediction and control system for large clusters We collected event logs containing various system reliability, availability and serviceability (RAS) events, and system activity reports (SARs) from a 350-node cluster system for a period of one year The 'raw' system health measurements contain a great deal of redundant event data, which is either repetitive in nature or misaligned with respect to time We applied a filtering technique and modeled the data into a set of primary and derived variables These variables used probabilistic networks for establishing event correlations through prediction algorithms We also evaluated the role of time-series methods, rule-based classification algorithms and Bayesian network models in event predictionBased on historical data, our results suggest that it is feasible to predict system performance parameters (SARs) with a high degree of accuracy using time-series models Rule-based classification techniques can be used to extract machine-event signatures to predict critical events with up to 70% accuracy

Phonological sensitivity: A quasi‐parallel progression of word structure units and cognitive operations

Abstract: This study investigated the order of acquisition of phonological sensitivity skills among preschool and kindergarten children. Phonological sensitivity was examined in terms of four levels of linguistic complexity (words, syllables, onsets and rimes, phonemes) across four levels of task complexity (blending detection, elision detection, blending, and elision). Participants were 947 two- to five-year-old children from diverse backgrounds. Hierarchical loglinear analyses evidenced a quasi-parallel pattern of development that corresponded to a hierarchical model of word structure and a working memory model of task complexity. Findings support a developmental conceptualization of phonological sensitivity. Findings are discussed in relation to their implications for improving assessment, early literacy instruction, and prevention of reading difficulties.

Efficacy and toxicity of caspofungin in combination with liposomal amphotericin B as primary or salvage treatment of invasive aspergillosis in patients with hematologic malignancies

Abstract: BACKGROUND Caspofungin (CAS) as salvage therapy for refractory invasive aspergillosis (IA) had a response rate of 45% among a heterogeneous group of patients. The use of CAS with other agents is appealing given its unique mechanism of action. Therefore, the authors retrospectively evaluated the efficacy and toxicity of CAS plus liposomal amphotericin B (LipoAMB) in patients with documented (definite or probable) or possible IA. METHODS Patients were evaluable for outcome if they received CAS/LipoAMB for at least 7 days. Patients who received CAS and LipoAMB sequentially were excluded. All patients were evaluable for toxicity. Outcome was assessed weekly and at the end of therapy. Stable disease and progression were considered treatment failures. RESULTS Forty-eight patients with documented (n = 23) or possible (n = 25) IA were identified between March 2001 and December 2001. The majority of the patients (65%) received CAS/LipoAMB as salvage therapy for progressive IA despite 7 or more days of previous LipoAMB monotherapy. The overall response rate was 42%. No significant toxic effects were seen. Factors associated with failure at the end of therapy were documented IA (P = 0.03), significant steroid use before the study (P = 0.02), and duration of combination therapy for less than14 days (P =0.01). The response rate in patients with progressive documented IA was low (18%). CONCLUSIONS The CAS/LipoAMB combination is a promising preemptive therapy for IA and was generally well tolerated. This combination might have limited benefit as salvage therapy for documented IA. Cancer 2003;98:292–9. © 2003 American Cancer Society. DOI 10.1002/cncr.11479