Showing papers by "University of Houston published in 2006"

Reporting structural equation modeling and confirmatory factor analysis results: A review

Abstract: The authors provide a basic set of guidelines and recommendations for information that should be included in any manuscript that has confirmatory factor analysis or structural equation modeling as the primary statistical analysis technique. The authors provide an introduction to both techniques, along with sample analyses, recommendations for reporting, evaluation of articles in The Journal of Educational Research using these techniques, and concluding remarks.

Insights into social insects from the genome of the honeybee Apis mellifera

Abstract: Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.

Financial Constraints Risk

Abstract: We construct an index of firms’ external finance constraints via generalized method of moments (GMM) estimation of an investment Euler equation. Unlike the commonly used KZ index, ours is consistent with firm characteristics associated with external finance constraints. Constrained firms’ returns move together, suggesting the existence of a financial constraints factor. This factor earns a positive but insignificant average return. Much of the variation in this factor cannot be explained by the Fama–French and momentum factors. Cross-sectional regressions of returns on our index and other firm characteristics show that constrained firms earn higher returns and that the financial-constraints effect dominates the size effect. We explore the impact of firms’ external finance constraints on their stock returns. Motivation for this inquiry starts with a large body of microeconometric studies that have provided some evidence of an impact of external finance constraints on investment. For example, Whited (1992), Bond and Meghir (1994), and Love (2003) show that augmentations of an investment Euler equation that account for financial constraints improve its fit. The question remains whether these effects are priced in asset markets. In other words, do financial constraints affect asset returns; and if so, is this risk diversifiable? To tackle this question, we construct an index of financial constraints based on a standard intertemporal investment model augmented to account for financial frictions. The model predicts that external finance constraints affect the intertemporal substitution of investment today for investment tomorrow via the shadow value of scarce external funds. This shadow value in turn depends on observable variables. Generalized method of moments (GMM) estimation of the model provides fitted values of the shadow value, which we then use as our index. The most important advantage of this approach is its avoidance of serious sample selection, simultaneity, and measurement-error problems via structural

Time to Initiation of Fluconazole Therapy Impacts Mortality in Patients with Candidemia: A Multi-Institutional Study

Abstract: BACKGROUND Inadequate antimicrobial treatment is an independent determinant of hospital mortality, and fungal bloodstream infections are among the types of infection with the highest rates of inappropriate initial treatment. Because of significant potential for reducing high mortality rates, we sought to assess the impact of delayed treatment across multiple study sites. The goals our analyses were to establish the frequency and duration of delayed antifungal treatment and to evaluate the relationship between treatment delay and mortality. METHODS We conducted a retrospective cohort study of patients with candidemia from 4 medical centers who were prescribed fluconazole. Time to initiation of fluconazole therapy was calculated by subtracting the date on which fluconazole therapy was initiated from the culture date of the first blood sample positive for yeast. RESULTS A total of 230 patients (51% male; mean age +/- standard deviation, 56 +/- 17 years) were identified; 192 of these had not been given prior treatment with fluconazole. Patients most commonly had nonsurgical hospital admission (162 patients [70%]) with a central line catheter (193 [84%]), diabetes (68 [30%]), or cancer (54 [24%]). Candida species causing infection included Candida albicans (129 patients [56%]), Candida glabrata (38 [16%]), Candida parapsilosis (25 [11%]), or Candida tropicalis (15 [7%]). The number of days to the initiation of antifungal treatment was 0 (92 patients [40%]), 1 (38 [17%]), 2 (33 [14%]) or > or = 3 (29 [12%]). Mortality rates were lowest for patients who began therapy on day 0 (14 patients [15%]) followed by patients who began on day 1 (9 [24%]), day 2 (12 [37%]), or day > or = 3 (12 [41%]) (P = .0009 for trend). Multivariate logistic regression was used to calculate independent predictors of mortality, which include increased time until fluconazole initiation (odds ratio, 1.42; P < .05) and Acute Physiology and Chronic Health Evaluation II score (1-point increments; odds ratio, 1.13; P < .05). CONCLUSION A delay in the initiation of fluconazole therapy in hospitalized patients with candidemia significantly impacted mortality. New methods to avoid delays in appropriate antifungal therapy, such as rapid diagnostic tests or identification of unique risk factors, are needed.

The genome of the sea urchin Strongylocentrotus purpuratus.

Abstract: We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.

MPI-DING reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

Abstract: We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented.

Bulk characterization methods for non-centrosymmetric materials: second-harmonic generation, piezoelectricity, pyroelectricity, and ferroelectricity.

Abstract: Characterization methods for bulk non-centrosymmetric compounds are described. These methods include second-harmonic generation, piezoelectricity, pyroelectricity, and ferroelectricity. In this tutorial review with each phenomenon, details are given of the measurement techniques along with a brief history and background. Finally, data interpretation is discussed.

Marmousi2 An elastic upgrade for Marmousi

Abstract: The original Marmousi model was created by a consortium led by the Institut Francais du Petrole (IFP) in 1988. Since its creation, the model and its acoustic finite-difference synthetic data have been used by hundreds of researchers throughout the world for a multitude of geophysical purposes, and to this day remains one of the most published geophysical data sets. The advancement in computer hardware capabilities since the late 1980s has made it possible to perform a major upgrade to the model and data set, thereby extending the usefulness of the model for, hopefully, some time to come. This paper outlines the creation of an updated and upgraded Marmousi model and data set which we have named Marmousi2.

The cognitive correlates of third-grade skill in arithmetic, algorithmic computation, and arithmetic word problems

Abstract: The purpose of this study was to examine the cognitive correlates of 3rd-grade skill in arithmetic, algorithmic computation, and arithmetic word problems. Third graders (N = 312) were measured on language, nonverbal problem solving, concept formation, processing speed, long-term memory, working memory, phonological decoding, and sight word efficiency as well as on arithmetic, algorithmic computation, and arithmetic word problems. Teacher ratings of inattentive behavior also were collected. Path analysis indicated that arithmetic was linked to algorithmic computation and to arithmetic word problems and that inattentive behavior independently predicted all 3 aspects of mathematics performance. Other independent predictors of arithmetic were phonological decoding and processing speed. Other independent predictors of arithmetic word problems were nonverbal problem solving, concept formation, sight word efficiency, and language.

Transformational leadership, initiating structure, and substitutes for leadership: a longitudinal study of research and development project team performance.

Abstract: Transformational leadership, initiating structure, and selected substitutes for leadership were studied as longitudinal predictors of performance in 118 research and development (R&D) project teams from 5 firms. As hypothesized, transformational leadership predicted 1-year-later technical quality, schedule performance, and cost performance and 5-year-later profitability and speed to market. Initiating structure predicted all the performance measures. The substitutes of subordinate ability and an intrinsically satisfying task each predicted technical quality and profitability, and ability predicted speed to market. Moderator effects for type of R&D work were hypothesized and found whereby transformational leadership was a stronger predictor of technical quality in research projects, whereas initiating structure was a stronger predictor of technical quality in development projects. Implications for leadership theory and research are discussed.

Invasive fungal infections in patients with hematologic malignancies in a tertiary care cancer center: an autopsy study over a 15-year period (1989-2003).

Abstract: We evaluated autopsy-proven invasive fungal infections (IFI) in patients with hematologic malignancies over three periods (1989-1993, 1994-1998, and 1999-2003). The autopsy rate declined significantly (67%-34%-26%, respectively p<0.0001). IFI were identified in 314 (31%) of 1017 autopsies. Most IFI (75%) were not diagnosed antemortem. The prevalence of invasive mold infections increased significantly (19%-24%-25% p=0.05) in parallel with the emergence of Zygomycetes (0.9%-4%-3%; p=0.03). The prevalence of all other IFI remained relatively constant. Among patients with invasive pulmonary aspergillosis, those with graft-versus-host disease had a histopathological pattern distinct from those with neutropenia. The complex and evolving epidemiology of IFI in severely immunocompromised patients is not well captured by current diagnostic methods.

Fluid mobility and frequency-dependent seismic velocity — Direct measurements

Abstract: The influence of fluid mobility on seismic velocity dispersion is directly observed in laboratory measurements from seismic to ultrasonic frequencies. A forceddeformation system is used in conjunction with pulse transmission to obtain elastic properties at seismic strain amplitude (10 −7 ) from 5 Hz to 800 kHz. Varying fluid types and saturations document the influence of pore-fluids. The ratio of rock permeability to fluid viscosity defines mobility, which largely controls pore-fluid motion and pore pressure in a porous medium. High fluid mobility permits pore-pressure equilibrium either between pores or between heterogeneous regions, resulting in a low-frequency domain where Gassmann’s equations are valid. In contrast, low fluid mobility can produce strong dispersion, even within the seismic band. Here, the low-frequency assumption fails. Since most rocks in the general sedimentary section have very low permeability and fluid mobility (shales, siltstones, tight limestones, etc.), most rocks are not in the lowfrequency domain, even at seismic frequencies. Only those rocks with high permeability (porous sands and carbonates) will remain in the low-frequency domain in the seismic or sonic band.

Estimating the number of American children living in partner-violent families.

Abstract: The number of American children living in partner-violent households was estimated from a nationally representative sample of 1,615 dual-parent households. Approximately 15.5 million American children were estimated to live in families in which partner violence had occurred at least once in the previous year, with 7 million estimated to live in families in which severe partner violence had occurred. The prevalence of partner violence was higher among couples with children than among couples without children.

Does Asymmetric Information Drive Capital Structure Decisions

Abstract: Using a novel information asymmetry index based on measures of adverse selection developed by the market microstructure literature, we test if information asymmetry is an important determinant of capital structure decisions, as suggested by the pecking order theory. Our index relies exclusively on measures of the market's assessment of adverse selection risk rather than on ex ante firm characteristics. We find that information asymmetry does affect the capital structure decisions of U.S. firms over the sample period 1973-2002. Our findings are robust to controlling for conventional leverage factors (size, Q ratio, tangibility, profitability) and several firm attributes, such as funding needs, sales growth, real investment, stock return volatility, stock turnover, and intensity of insider trading. For example, we estimate that on average, for every dollar of financing deficit to cover, firms in the highest adverse selection decile issue 30 cents of debt more than firms in the lowest decile. Overall, this evidence explains why the pecking order theory is only partially successful in explaining all of firms' capital structure decisions. It also suggests that the theory finds support when its basic assumptions hold in the data, as it should reasonably be expected of any theory.

The Educational Uses of Digital Storytelling

Abstract: Digital Storytelling has become a powerful instructional tool for both students and educators. This article presents an overview of Digital Storytelling and describes where it came from, how it can be used to support instruction and how students who learn to create their own digital stories improve multiple literacy skills. In addition, information is presented about the tools that can be used to support the educational use of Digital Storytelling. The article also includes a discussion of challenges and other important considerations that students and educators should be aware of before implementing the use of Digital Storytelling in the classroom, and concludes with an overview of the research that has been and needs to be conducted on the effectiveness of Digital Storytelling as a teaching and learning tool. Author note: The Educational Uses of Digital Storytelling website, created at the University Houston, features example digital stories and helpful information for those interested in learning how to create their own digital stories. The website provides additional information on many of the topics discussed in this article.

The ACS Virgo Cluster Survey. VI. Isophotal Analysis and the Structure of Early-Type Galaxies

Abstract: (Abridged) We present a detailed analysis of the morphology, isophotal parameters and surface brightness profiles for 100 early-type members of the Virgo Cluster, from dwarfs (M_B = -15.1 mag) to giants (M_B = -21.8 mag). Each galaxy has been imaged in two filters, closely resembling the Sloan g and z passbands, using the Advanced Camera for Surveys on board the Hubble Space Telescope. Dust and complex morphological structures are common, with kiloparsec-scale stellar disks, bars, and nuclear stellar disks seen in 60% of galaxies with intermediate luminosity (-20 < M_B < -17), and dust seen in 42% of galaxies brighter than M_B = -18.9 mag. Dust morphologies range from faint wisps and patches on tens of parsec scales, to regular, highly organized kpc-scale dust disks, often showing evidence of recent star formation. Surface brightness profiles and isophotal parameters are derived typically within 8 kpc from the center for the brightest galaxies, and 1.5 kpc for the faintest systems, with a resolution (FWHM) of 7 pc. Based on a parametrization of the surface brightness profiles in terms of a Sersic or core-Sersic model, we find that 1) there is no evidence of a bimodal behavior of the slope, gamma, of the profile in the innermost regions; 2) although the brightest galaxies have shallow inner profiles, the shallowest profiles (lowest gamma values) are found in faint dwarf systems; 3) the widely adopted separation of early-type galaxies between "core" and "power-law" types, which had originally been prompted by the claim of a clear bimodal distribution of gamma values, is untenable; and 4) there is no evidence of a structural dichothomy between dwarf and regular ellipticals.

Nonlinear dynamics of networks: the groupoid formalism

Abstract: A formal theory of symmetries of networks of coupled dynamical systems, stated in terms of the group of permutations of the nodes that preserve the network topology, has existed for some time. Global network symmetries impose strong constraints on the corresponding dynamical systems, which affect equilibria, periodic states, heteroclinic cycles, and even chaotic states. In particular, the symmetries of the network can lead to synchrony, phase relations, resonances, and synchronous or cycling chaos. Symmetry is a rather restrictive assumption, and a general theory of networks should be more flexible. A recent generalization of the group-theoretic notion of symmetry replaces global symmetries by bijections between certain subsets of the directed edges of the network, the ‘input sets’. Now the symmetry group becomes a groupoid, which is an algebraic structure that resembles a group, except that the product of two elements may not be defined. The groupoid formalism makes it possible to extend group-theoretic methods to more general networks, and in particular it leads to a complete classification of ‘robust’ patterns of synchrony in terms of the combinatorial structure of the network. Many phenomena that would be nongeneric in an arbitrary dynamical system can become generic when constrained by a particular network topology. A network of dynamical systems is not just a dynamical system with a high-dimensional phase space. It is also equipped with a canonical set of observables—the states of the individual nodes of the network. Moreover, the form of the underlying ODE is constrained by the network topology—which variables occur in which component equations, and how those equations relate to each other. The result is a rich and new range of phenomena, only a few of which are yet properly understood.

Shame Resilience Theory: A Grounded Theory Study on Women and Shame

Abstract: Although shame is one of the most primitive and universal of human emotions, it is often still considered a taboo topic among researchers, practitioners, and clients. This paper presents the empirical foundation for shame resilience theory-a new theory for understanding shame and its impact on women. Using grounded theory methodology, 215 women were interviewed to determine why and how women experience shame and to identify the various processes and strategies women use to develop shame resilience. The article describes the major theoretical categories, including acknowledged vulnerability, critical awareness, and mutually empathic relationships, and introduces the concept of speaking shame. Practice implications are explored, including the importance of psychoeducational group work in building shame resilience.

Did Conservatism in Financial Reporting Increase after the Sarbanes‐Oxley Act? Initial Evidence

Abstract: In this paper, we investigate the change in managerial discretion over financial reporting following the Sarbanes‐Oxley Act (hereafter SOX). We document an increase in conservatism in financial reporting following SOX and the resulting requirement by the SEC that financial statements be certified by firms' CEOs and CFOs. First, we find that firms report lower discretionary accruals after SOX than in the period preceding SOX. Second, based on the Basu (1997) measure of conservatism, we find that firms incorporate losses more quickly than gains when they report income in the post‐SOX period. These results are obtained with alternative estimation and measurement approaches and after controlling for potentially confounding variables. This empirical evidence suggests that SOX and the resultant SEC certification requirement may have altered management's discretionary reporting behavior to make it more conservative.

Unraveling the sequence of serpentinization reactions: petrography, mineral chemistry, and petrophysics of serpentinites from MAR 15°N (ODP Leg 209, Site 1274)

Abstract: [1] The results of detailed textural, mineral chemical, and petrophysical studies shed new light on the poorly constrained fluid-rock reaction pathways during retrograde serpentinization at mid-ocean ridges. Uniformly depleted harzburgites and dunites from the Mid-Atlantic Ridge at 15� N show variable extents of static serpentinization. They reveal a simple sequence of reactions: serpentinization of olivine and development of a typical mesh texture with serpentine-brucite mesh rims, followed by replacement of olivine mesh centers by serpentine and brucite. The serpentine mesh rims on relic olivine are devoid of magnetite. Conversely, domains in the rock that are completely serpentinized show abundant magnetite. We propose that low-fluid-flux serpentinization of olivine to serpentine and ferroan brucite is followed by later stages of serpentinization under more open-system conditions and formation of magnetite by the breakdown of ferroan brucite. Modeling of this sequence of reactions can account for covariations in magnetic susceptibility and grain density of the rocks. Citation: Bach, W., H. Paulick, C. J. Garrido, B. Ildefonse, W. P. Meurer, and S. E. Humphris (2006), Unraveling the sequence of serpentinization reactions: petrography, mineral chemistry, and petrophysics of serpentinites from MAR 15� N (ODP Leg 209, Site 1274), Geophys. Res. Lett., 33, L13306,

3D volumetric multispectral estimates of reflector curvature and rotation

Abstract: One of the most accepted geologic models is the relation between reflector curvature and the presence of open and closed fractures. Such fractures, as well as other small discontinuities, are relatively small and below the imaging rangeofconventionalseismicdata.Dependingonthetectonic regime, structural geologists link open fractures to either Gaussian curvature or to curvature in the dip or strike directions. Reflector curvature is fractal in nature, with different tectonic and lithologic effects being illuminated at the 50-m and1000-m scales.Untilnow,suchcurvatureestimateshave been limited to the analysis of picked horizons. We have developed what we feel to be the first volumetric spectral estimates of reflector curvature. We find that the most positive and negative curvatures are the most valuable in the conventional mapping of lineations — including faults, folds, and flexures.Curvatureismathematicallyindependentof,andinterpretatively complementary to, the well-established coherence geometric attribute. We find the long spectral wavelengthcurvatureestimatestobeofparticularvalueinextracting subtle, broad features in the seismic data such as folds, flexures, collapse features, fault drags, and under- and overmigrated fault terminations. We illustrate the value of these spectral curvature estimates and compare them to other attributes through application to two land data sets — a salt domefromtheonshoreLouisianaGulfCoastandafractured/ karsteddatavolumefromFortWorthbasinofNorthTexas.

Evidence OF the Effect of Trust Building Technology in Electronic Markets: Price Premiums and Buyer Behavior

Abstract: Despite the wide use of reputational mechanisms such as eBay's Feedback Forum to promote trust, empirical studies have shown conflicting results as to whether online feedback mechanisms induce trust and lead to higher auction prices. This study examines the extent to which trust can be induced by proper feedback mechanisms in electronic markets, and how some risk factors play a role in trust formation. Drawing from economic, sociological, and marketing theories and using data from both an online experiment and an online auction market, we demonstrate that appropriate feedback mechanisms can induce calculus-based credibility trust without repeated interactions between two transacting parties. Trust can mitigate information asymmetry by reducing transaction-specific risks, therefore generating price premiums for reputable sellers. In addition, the research also examines the role that trust plays in mitigating the risks inherent in transactions that involve very expensive products.

Combination of voriconazole and caspofungin as primary therapy for invasive aspergillosis in solid organ transplant recipients: A prospective, multicenter, observational study

Abstract: Background : The efficacy of the combination of voriconazole and caspofungin when used as primary therapy for invasive aspergillosis in organ transplant recipients has not been defined. Methods : Transplant recipients who received voriconazole and caspofungin (n=40) as primary therapy for invasive aspergillosis (proven or probable) in a prospective multicenter study between 2003 and 2005 were compared to a control group comprising a cohort of consecutive transplant recipients between 1999 and 2002 who had received a lipid formulation of AmB as primary therapy (n=47). In vitro antifungal testing of Aspergillus isolates to combination therapy was correlated with clinical outcome. Results : Survival at 90 days was 67.5% (27/40) in the cases, and 51% (24/47) in the control group (HR 0.58, 95% CI, 0.30-1.14, P=0.117). However, in transplant recipients with renal failure (adjusted HR 0.32, 95% CI: 0.12-0.85, P=0.022), and in those with A. fumigatus infection (adjusted HR 0.37, 95% CI: 0.16-0.84, P=0.019), combination therapy was independently associated with an improved 90-day survival in multivariate analysis. No correlation was found between in vitro antifungal interactions of the Aspergillus isolates to the combination of voriconazole and caspofungin and clinical outcome. Conclusions : Combination of voriconazole and caspofungin might be considered preferable therapy for subsets of organ transplant recipients with invasive aspergillosis, such as those with renal failure or A. fumigatus infection.

Electromechanical coupling in nonpiezoelectric materials due to nanoscale nonlocal size effects: Green’s function solutions and embedded inclusions

Abstract: In a piezoelectric material, an applied uniform strain can induce an electric polarization (or vice versa). Crystallographic considerations restrict this technologically important property to noncentrosymmetric systems. It has been shown both mathematically and physically that a nonuniform strain can potentially break the inversion symmetry and induce polarization in nonpiezoelectric materials. The coupling between strain gradients and polarization, and conversely between strain and polarization gradients, is investigated in this work. While the conventional piezoelectric property is nonzero only for certain select materials, the nonlocal coupling of strain and electric field gradients is (in principle) nonzero for all dielectrics, albeit manifesting noticeably only at the nanoscale, around interfaces or in general in the vicinity of high field gradients. Based on a field theoretic framework accounting for this phenomena, we (i) develop the fundamental solutions (Green's functions) for the governing equations, and (ii) motivated by eventual applications for quantum dots, solve the general embedded mismatched inclusion problem with explicit results for the spherical and cylindrical shape. Expectedly, our results for the aforementioned problems are size dependent and indicate generation of high electric fields reaching values of approximately hundreds of kV/m in selected sizes and locations---even in isotropic centrosymmetric nonpiezoelectric materials.

Oral Language and Reading in Bilingual Children

Abstract: This article examines the question: Do lexical, syntactic, fluency, and discourse measures of oral language collected under narrative conditions predict reading achievement both within and across languages for bilingual children? More than 1,500 Spanish–English bilingual children attending kindergarten–third grade participated. Oral narratives were collected in each language along with measures of Passage Comprehension and Word Reading Efficiency. Results indicate that measures of oral language in Spanish predict reading scores in Spanish and that measures of oral language skill in English predict reading scores in English. Cross-language comparisons revealed that English oral language measures predicted Spanish reading scores and Spanish oral language measures predicted English reading scores beyond the variance accounted for by grade. Results indicate that Spanish and English oral language skills contribute to reading within and across languages.

Earnings Management and Firm Performance Following Open-Market Repurchases

Abstract: We provide evidence suggesting that both the post-repurchase long-term abnormal returns and the reported improvement in operating performance documented in prior studies are driven, at least partly, by pre-repurchase downward earnings management, rather than genuine growth in profitability The average firm reports significantly negative abnormal accruals prior to open-market repurchases The extent of the downward earnings management increases with the percentage of the company that managers repurchase and CEO ownership The pre-repurchase abnormal accruals are also significantly negatively associated with both future operating performance and future stock performance, and the negative associations are driven almost exclusively by those firms that report the largest income-decreasing abnormal accruals prior to the repurchases The study suggests that one reason firms experience post-repurchase abnormal returns is that the post-repurchase realized earnings growth exceeds expectations formed on the basis of the pre-repurchase deflated earnings numbers