Showing papers by "University of Houston published in 1996"
TL;DR: In this paper, the authors present a test of independence that can be applied to the estimated residuals of any time series model, which can be transformed into a model driven by independent and identically distributed errors.
Abstract: This paper presents a test of independence that can be applied to the estimated residuals of any time series model that can be transformed into a model driven by independent and identically distributed errors. The first order asymptotic distribution of the test statistic is independent of estimation error provided that the parameters of the model under test can be estimated -consistently. Because of this, our method can be used as a model selection tool and as a specification test. Widely used software1 written by Dechert and LeBaron can be used to implement the test. Also, this software is fast enough that the null distribution of our test statistic can be estimated with bootstrap methods. Our method can be viewed as a nonlinear analog of the Box-Pierce Q statistic used in ARIMA analysis.
2,723 citations
TL;DR: It is argued that research in the entrepreneurial context could benefit by providing a theorybased rationale for examining the given dimension(s), including multiple dimensions of performance where possible, and including consideration of several critical control variables such as industry, age, and size of the firm.
1,095 citations
TL;DR: It is proposed that the cumulative threat to female reproductive success of genetic incompatibility arising from intragenomic conflict may be an important force driving the evolution of polyandry.
Abstract: Why do females across a wide range of taxa mate with more than one male? We suggest that a better understanding of polyandry may be gained by considering the implications of intragenomic conflict for female reproductive success. Here, we revisit the literature on cellular endosymbionts, transposable elements, segregation distorters, maternal-effect lethals and genomically imprinted genes to show that each of these selfish genetic elements can modify maternal and paternal haplotypes in ways that render them incompatible within the developing embryo. We propose that the cumulative threat to female reproductive success of genetic incompatibility arising from intragenomic conflict may be an important force driving the evolution of polyandry. By mating with more than one male, females can potentially exploit post-copulatory mechanisms for minimizing the risk and/or cost of fertilization by genetically incompatible sperm. This hypothesis differs fundamentally from other genetic benefit models of polyandry in that the fitness consequences of intragenomic conflict depend on an interaction between parental genomes and are thus non-additive. Reciprocal evolutionary change between selfish genetic elements and their suppressors, combined with the capacity of these elements for horizontal transfer between species, is likely to ensure the persistence of genetic incompatibility as a threat to female reproductive success.
633 citations
TL;DR: In this article, the authors examine the global landscape and find that some cultures produce many more entrepreneurs than others, and they take a cognitive perspective because it is assumed that cultures tend to produce more entrepreneurs.
Abstract: In examining the global landscape, it is clear that some cultures produce many more entrepreneurs than others. To explore this phenomenon, we take a cognitive perspective because it is assumed that...
621 citations
TL;DR: In this article, a modified contagion theory was proposed to explain the representation gap between women's representation in national legislatures between countries with single-member district electoral systems and those with proportional representation electoral systems.
Abstract: There is a distinct gap in women's representation in national legislatures between countries with single-member district electoral systems and those with proportional representation electoral systems. While this gap has been well documented, there have been only limited attempts at explaining its existence. After reviewing the literature on the representation gap, we turn to the party change literature and propose a modified contagion theory as one possible explanation for the gap. Contagion theory suggests that traditional parties will feel pressured to nominate more women if one of their political rivals, usually a smaller party farther to the left, starts to promote representation of women. We distinguish between macrocontagion and microcontagion and argue that especially microcontagion is more likely to occur in party list proportional representation systems than in single-member district systems. This should be true because contagion pressures are more likely to develop, and the costs of adapting to ...
509 citations
TL;DR: This paper argued that the value of pre-startup planning is context-dependent, and suggested that the importance of planning is not only related to the success but also to the survival of new small businesses.
357 citations
TL;DR: The authors used Hofstede's cultural model as a tool for analyzing cultures and using advertising appeals identified by Pollay to shed light on the question of whether systematic differences in advertising content mirror predictable differences in the cultures themselves.
Abstract: Across cultures, do systematic differences in advertising content mirror predictable differences in the cultures themselves? The authors designed a study to shed light on that question, using Hofstede's cultural model as a tool for analyzing cultures and using advertising appeals identified by Pollay. After coding advertisements in business publications from 11 countries for the appeals employed, they computed correlation coefficients relating the proportional use of each appeal and Hofstede's cultural dimensions: individualism, uncertainty avoidance, power distance, and masculinity. The culture-reflecting quality of advertising was supported for 10 of 30 hypothesized relationships, and for an additional eight after removal of outliers from the data.
351 citations
TL;DR: In this article, the authors explore the intellectual structures upon which the field of information systems development (ISD) is cultivated, and propose a framework which reconceptualizes the field in terms of domains, orientations, object systems, and development strategies.
342 citations
TL;DR: It is demonstrated that beta ARK1 appears to be the predominant GRK in early embryogenesis and that it plays a fundamental role in cardiac development.
Abstract: The beta-adrenergic receptor kinase 1 (beta ARK1) is a member of the G protein-coupled receptor kinase (GRK) family that mediates the agonist-dependent phosphorylation and desensitization of G protein-coupled receptors. We have cloned and disrupted the beta ARK1 gene in mice by homologous recombination. No homozygote beta ARK1-/- embryos survive beyond gestational day 15.5. Prior to gestational day 15.5, beta ARK1-/- embryos display pronounced hypoplasia of the ventricular myocardium essentially identical to the "thin myocardium syndrome" observed upon gene inactivation of several transcription factors (RXR alpha, N-myc, TEF-1, WT-1). Lethality in beta ARK1-/- embryos is likely due to heart failure as they exhibit a > 70% decrease in cardiac ejection fraction determined by direct in utero intravital microscopy. These results along with the virtual absence of endogenous GRK activity in beta ARK1-/- embryos demonstrate that beta ARK1 appears to be the predominant GRK in early embryogenesis and that it plays a fundamental role in cardiac development.
339 citations
TL;DR: The BCM Search Launcher is an integrated set of World Wide Web pages that organize molecular biology-related search and analysis services available on the WWW by function, and provide a single point of entry for related searches.
Abstract: The BCM Search Launcher is an integrated set of World Wide Web (WWW) pages that organize molecular biology-related search and analysis services available on the WWW by function, and provide a single point of entry for related searches. The Protein Sequence Search Page, for example, provides a single sequence entry form for submitting sequences to WWW servers that offer remote access to a variety of different protein sequence search tools, including BLAST, FASTA, Smith-Waterman, BEAUTY, PROSITE, and BLOCKS searches. Other Launch pages provide access to (1) nucleic acid sequence searches, (2) multiple and pair-wise sequence alignments, (3) gene feature searches, (4) protein secondary structure prediction, and (5) miscellaneous sequence utilities (e.g., six-frame translation). The BCM Search Launcher also provides a mechanism to extend the utility of other WWW services by adding supplementary hypertext links to results returned by remote servers. For example, links to the NCBI's Entrez data base and to the Sequence Retrieval System (SRS) are added to search results returned by the NCBI's WWW BLAST server. These links provide easy access to auxiliary information, such as Medline abstracts, that can be extremely helpful when analyzing BLAST data base hits. For new or infrequent users of sequence data base search tools, we have preset the default search parameters to provide the most informative first-pass sequence analysis possible. We have also developed a batch client interface for Unix and Macintosh computers that allows multiple input sequences to be searched automatically as a background task, with the results returned as individual HTML documents directly to the user's system. The BCM Search Launcher and batch client are available on the WWW at URL http:@gc.bcm.tmc.edu:8088/search-launcher.html.
338 citations
01 Jan 1996
TL;DR: These results are published by NASA in the NASA STI Report Series, which includes the following report types: Reports of completed research or a major significant phase of research that present the results of NASA programs and include extensive data or theoretical analysis.
Abstract: This chapter contains sections titled: Introduction to Probabilistic Risk Assessment Initiating-Event Search The Three PRA Levels Risk Calculations Example of a Level 3 PRA Benefits, Detriments, and Successes of PRA This chapter contains sections titled: References Chapter Three Appendices Problems
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TL;DR: This work focuses on the stabilization and the suboptimal H"~ output feedback control design problems, described by a pair of LMIs and an additional coupling condition, which is convex for the full-order control design problem, but convexity is lost for the control problem of order strictly less than the plant order.
TL;DR: In this article, an experimental system and methodology were developed to realize dry etching of single crystal silicon with monolayer accuracy, which was self-limiting with respect to both reactant and ion dose.
Abstract: An experimental system and methodology were developed to realize dry etching of single crystal silicon with monolayer accuracy. Atomic layer etching of silicon is a cyclic process composed of four consecutive steps: reactant adsorption, excess reactant evacuation, ion irradiation, and product evacuation. When successful, completion of one cycle results in removal of one monolayer of silicon. The process was self‐limiting with respect to both reactant and ion dose. Control of the ion energy was the most important factor in realizing etching of one monolayer per cycle.
TL;DR: Neither the conventional wisdom that cognition is intact in nearly all patients with amyotrophic lateral sclerosis, nor more recent suggestions that Cognition is often at least mildly impaired seems to be correct.
Abstract: OBJECTIVE: To determine the prevalence and correlates of neuropsychological impairment in a large cohort (n = 146) of patients with typical, sporadic (non-familial) amyotrophic lateral sclerosis. METHODS: A battery of neuropsychological tests was administered to patients with amyotrophic lateral sclerosis who were attending a monthly outpatient clinic or who were in hospital undergoing diagnostic tests. RESULTS: Comparing individual patient's scores with relevant normative data, 35.6% of the patients displayed evidence of clinically significant impairment, performing at or below the 5th percentile on at least two of the eight neuropsychological measures. Deficits were most common in the areas of problem solving, attention/mental control, continuous visual recognition memory, word generation, and verbal free recall. Impairment was most prevalent in patients with dysarthria (48.5%), but 27.4% of non-dysarthric patients were also impaired. Impaired patients had more severe or widespread symptoms of amyotrophic lateral sclerosis than non-impaired patients, and had fewer years of education. CONCLUSION: Neither the conventional wisdom that cognition is intact in nearly all patients with amyotrophic lateral sclerosis, nor more recent suggestions that cognition is often at least mildly impaired seems to be correct. A minority of patients with amyotrophic lateral sclerosis displayed evidence of significant impairment. Dysarthria, low education, and greater severity of motor symptoms were risk factors for impairment.
TL;DR: Results of Receiver Operator Characteristic (ROC) analyses using %BF and total body fat, both provided a BMI of 25 kg/m2 in men and 23 kg/ m2 in women as diagnostic screening cut offs for obesity.
Abstract: The aims of this study were to evaluate the Body Mass Index (BMI) (weight/stature2) as a proxy for percent body fat (%BF) and to determine its association with fat-free mass (FFM). Multivariate analysis of variance and partial correlations were used to examine relationships between BMI and %BF and FFM from densitometry for 504 men and 511 women, aged 20 to 45 years. Sensitivity/specificity analyses used cut offs of 28 kg/m2 in men and 26 kg/m2 in women for BMI, and 25% in men and 33% in women for %BF. Significantly higher associations existed in each gender between BMI and %BF in the upper BMI tertile than in the lower BMI tertiles. In the lower BMI tertiles, correlations between BMI and FFM were approximately twice as large as those between BMI and %BF. The BMI correctly identified about 44% of obese men, and 52% of obese women when obesity was determined from %BF. BMI is an uncertain diagnostic index of obesity. Results of Receiver Operator Characteristic (ROC) analyses using %BF and total body fat, both provided a BMI of 25 kg/m2 in men and 23 kg/m2 in women as diagnostic screening cut offs for obesity.
TL;DR: A combinatorial library of catalyst candidates, each consisting of a different metal element supported on γ-alumina, is screened for hydrogen oxidation catalytic activity by noninvasive IR thermography as mentioned in this paper.
Abstract: A combinatorial library of catalyst candidates, each consisting of a different metal element supported on γ-alumina, is screened for hydrogen oxidation catalytic activity Heat liberated on the surface of active catalysts by the catalyzed reaction is detected by noninvasive IR thermography A 16-candidate library identifies four distinctly active pellets, which correspond to active formulations known from the literature A higher density library shows similar results, but heat and mass transport effects influence the pellet temperatures This method may be used to screen and optimize catalyst formulations more efficiently and quickly than current methods and may also be useful for study of operational lifetime, resistance to poisons, and regenerability
TL;DR: The zebrafish pineal should be useful for in vitro studies of vertebrate circadian clock mechanisms and the phase of this rhythm was reset by in vitro exposure to phase-shifted light cycles.
TL;DR: In this paper, the authors review the prevailing interpretation of European parliamentary elections as second-order national elections, a view first put forward by Reif and Schmitt in 1980, and suggest that the secondorder features of European elections should be thought of as contextual variables that can affect other elections as well.
TL;DR: Previously used models, such as those used to identify “allocative inefficiencies”, are extended by means of “assurance region” approaches which are less demanding in their information requirements and underlying assumptions.
Abstract: The extensions, new developments and new interpretations for DEA covered in this paper include: (1) new measures of efficiency, (2) new models and (3) new ways of implementing established models with new results and interpretations presented that include treatments of “congestion”, “returns-to-scale” and “mix” and “technical” inefficiencies and measures of efficiency that can be used to reflect all pertinent properties. Previously used models, such as those used to identify “allocative inefficiencies”, are extended by means of “assurance region” approaches which are less demanding in their information requirements and underlying assumptions. New opportunities for research are identified in each section of this chapter. Sources of further developments and possible sources for further help are also suggested with references supplied to other papers that appear in this volume and which are summarily described in this introductory chapter.
TL;DR: It is concluded that strong and significant improvement of Vernier acuity in human adults with naturally occurring amblyopia following practice reflects alterations in early neural processes that are localized beyond the site of convergence of the two eyes.
Abstract: Amblyopia is a neuronal abnormality of vision that is often considered irreversible in adults. We found strong and significant improvement of Vernier acuity in human adults with naturally occurring amblyopia following practice. Learning was strongest at the trained orientation and did not transfer to an untrained task (detection), but it did transfer partially to the untrained eye (primarily at the trained orientation). We conclude that this perceptual learning reflects alterations in early neural processes that are localized beyond the site of convergence of the two eyes. Our results suggest a significant degree of plasticity in the visual system of adults with amblyopia.
TL;DR: To determine the evolutionary relationships among specific 14-3-3 proteins in different plant, animal, and fungal species and to initiate a predictive analysis of isoform-specific differences, multiple alignments were constructed from forty-six 14- 3-3 sequences retrieved from the GenBank and SwissProt databases and a newly identified second 14-2-3 gene from Caenorhabditis elegans.
Abstract: Members of the highly conserved and ubiquitous 14-3-3 protein family modulate a wide variety of cellular processes. To determine the evolutionary relationships among specific 14-3-3 proteins in different plant, animal, and fungal species and to initiate a predictive analysis of isoform-specific differences in light of the latest functional and structural studies of 14-3-3, multiple alignments were constructed from forty-six 14-3-3 sequences retrieved from the GenBank and SwissProt databases and a newly identified second 14-3-3 gene fromCaenorhabditis elegans. The alignment revealed five highly conserved sequence blocks. Blocks 2–5 correlate well with the alpha helices 3, 5, 7, and 9 which form the proposed internal binding domain in the three-dimensional structure model of the functioning dimer. Amino acid differences within the functional and structural domains of plant and animal 14-3-3 proteins were identified which may account for functional diversity amongst isoforms. Protein phylogenic trees were constructed using both the maximum parsimony and neighbor joining methods of the PHYLIP(3.5c) package; 14-3-3 proteins fromEntamoeba histolytica, an amitochondrial protozoa, were employed as an outgroup in our analysis. Epsilon isoforms from the animal lineage form a distinct grouping in both trees, which suggests an early divergence from the other animal isoforms. Epsilons were found to be more similar to yeast and plant isoforms than other animal isoforms at numerous amino acid positions, and thus epsilon may have retained functional characteristics of the ancestral protein. The known invertebrate proteins group with the nonepsilon mammalian isoforms. Most of the current 14-3-3 isoform diversity probably arose through independent duplication events after the divergence of the major eukaryotic kingdoms. Divergence of the seven mammalian isoforms beta, zeta, gamma, eta, epsilon, tau, and sigma (stratifin/ HME1) occurred before the divergence of mammalian and perhaps before the divergence of vertebrate species. A possible ancestral 14-3-3 sequence is proposed.
TL;DR: Positive trends, but no significant results, were observed in trial-wide smoking outcomes and the observed net differences were small owing to the substantial secular changes in target behaviors.
Abstract: OBJECTIVES. This paper presents the behavioral results of the Working Well Trial, the largest US work site cancer prevention and control trial to date. METHODS. The Working Well Trial used a randomized, matched-pair evaluation design, with the work site as the unit of assignment and analysis. The study was conducted in 111 work sites (n = 28,000 workers). The effects of the intervention were evaluated by comparing changes in intervention and control work sites, as measured in cross-sectional surveys at baseline and follow-up. The 2-year intervention targeted both individuals and the work-site environment. RESULTS. There occurred a net reduction in the percentage of energy obtained from fat consumption of 0.37 percentage points (P = .033), a net increase in fiber densities of 0.13 g/1000 kcal (P = .056), and an average increase in fruit and vegetable intake of 0.18 servings per day (P = .0001). Changes in tobacco use were in the desired direction but were not significant. CONCLUSIONS. Significant but small...
TL;DR: A strong correlation between thermostability and the number of hydrogen bonds between charged side chains and neutral partners is found and charged residues play a dual role in stabilization by participating not only in salt links but also in hydrogen bonds with a neutral partner.
Abstract: The crystal structure of holo d-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the extreme thermophile Thermus aquaticus has been solved at 2.5 A resolution. To study the determinants of the...
TL;DR: This article found that tropical cyclone rains have distinctly lower stable isotope ratios than rains in other tropical and summer precipitation systems, with a mean value slightly above that of water vapor near the sea surface.
Abstract: Tropical cyclone rains have distinctly lower stable isotope ratios than rains in other tropical and summer precipitation systems, with a mean value slightly above that of water vapor near the sea surface. The isotope ratios also decrease radially inward to the eye wall, but appear to be anomalously low even near the periphery of the rain shield. These findings indicate that tropical cyclones are highly efficient precipitation systems and suggest the use of stable isotope ratios as dynamic tracers of a tropical cyclone's water and energy budgets.
TL;DR: The design principle, tracking performance and stability analysis of a fuzzy proportional-integral (PI) plus a derivative (D) controller, derived from the conventional continuous-time linear PI+D controller, and computer simulation results have shown the new fuzzy controller indeed has satisfactory tracking performance.
TL;DR: The majority of the carbonaceous chondrite clasts found in howardites, eucrites and diogenites are CM2 material, a lesser proportion is CR2 material and other rare types are present as mentioned in this paper.
Abstract: The majority of the carbonaceous chondrite clasts found in howardites, eucrites and diogenites are CM2 material, a lesser proportion is CR2 material, and other rare types are present. A single clast that was found on the Moon and called the Bench Crater meteorite is apparently shocked CM1 material. The CM2 clasts are matrix supported mixtures of olivine-pyroxene-phyllosilicate-sulfide bearing aggregates, loose olivines and pyroxenes, sulfides, carbonates, and sinuous spinel-phyllosilicate-diopside calcium-aluminum-rich inclusions (CAIs). Magnetite and metal are rare. Some aggregates have fine-grained rims of material resembling matrix. The opaque, fine-grained matrix consists predominantly of serpentine of extremely variable composition and sulfides; tochilinite is occasionally present. The trace element data for one Jodzie clast from this study and the average of similar clasts from Kapoeta support a CM classification; volatiles are depleted relative to CI and enriched relative to CR material.
The CR2 clasts are found (in small numbers) in only four howardites: Bholghati, Jodzie, Kapoeta and Y793497. Petrographically, they are matrix-supported mixtures of olivine aggregates (sometimes containing sulfides), loose olivines, pyrrhotite, pentlandite, low-Ca pyroxene (minor), hedenbergite (rare), kamacite (rare and only found within olivine), Ca-carbonates and abundant magnetite framboids and plaquets. Phyllosilicates are fine-grained and largely confined to matrix; they are mixtures of serpentine and saponite. The matrix of CR2 clasts also contains pyrrhotite, pentlandite, chromite and a significant fraction of poorly-crystalline material with the same bulk composition as matrix phyllosilicate.
There is evidence of heating in a substantial number of clasts, both CM2 and CR2, including: (1) corrugated serpentine flakes, (2) pseudomorphs of anhydrous ferromagnesian material after flaky phyllosilicates, and (3) hedenbergite rims on calcite. While the timing of the hedenbergite rims is debatable, the destruction of phyllosilicates clearly occurred at a late stage, plausibly during impact onto the HED asteroid(s) and Moon, and required peak heating temperatures on the order of 400 °C.
We note that in general, CM2 material was the most common carbonaceous chondrite lithology impacting the HED asteroids (with howardites and eucrites taken together), as it is for the Earth today. A total of 61 out of 75 carbonaceous chondrite clasts from HED meteorites belong to the CM clan, petrologic grade 2. This is also supported by published siderophile and volatile element data on howardites, eucrites and diogenites that are taken to indicate that CM-like materials were the most common impactors on the HED asteroid(s). The ratio of CR/CM clasts in HED asteroids is essentially the same as for modern falls at Earth. This may indicate that the ratio of disaggregated CM2 to CR2 asteroidal material has been approximately constant through the history of the solar system. Finally, our results are also compatible with type-2 carbonaceous chondrites being equivalent to or from the same source as the material that originally accreted to form the HED asteroid.
TL;DR: In this paper, the authors conducted a survey of 837 firms identified in the Venture Capital Journal that had received financing from venture capital firms and found that significant differences exist among VCs in their evaluation of business management and operational assistance, and that the optimal level of involvement is also partially contingent upon the NVT openness to learning.
Journal Article•
TL;DR: A sensitive negative component is reduced or absent from the dark-adapted ERGs of macaque monkeys with severe visual field defects and substantial retinal ganglion cell loss as a consequence of long-standing ocular hypertension.
Abstract: PURPOSE This study describes the dark-adapted electroretinograms (ERGs) of macaque monkeys with severe visual field defects and substantial retinal ganglion cell loss as a consequence of long-standing ocular hypertension. METHODS Monocular experimental glaucoma was produced by argon laser trabeculoplasty, and visual fields were assessed with behavioral static perimetry. Electroretinographic responses to brief ganzfeld flashes under fully dark-adapted conditions were recorded using DTL fiber electrodes in anesthetized animals. The authors quantified retinal layer thickness and cell loss in 1-micron radial sections and inspected optic nervous under the light microscope. RESULTS At the lowest intensities, a sensitive negative component of the scotopic ERG, which normally peaks approximately 200 msec after stimulus onset, was present in the control eyes but was reduced greatly or was virtually absent in the experimental eyes of monkeys with severe visual field loss. A previously unreported sensitive positive component of the scotopic ERG remained in both eyes. In the control eyes, the positive component gave rise to a sharp peak approximately 120 msec after stimulus onset, but in the experimental eyes, because of the absence of the more delayed sensitive negative potential, it was sustained, lasting as long as 700 msec. Scotopic a- and b-waves and oscillatory potentials in the experimental eyes were not consistently different from control eyes. Ganglion cell and optic nerve loss in the experimental eyes was substantial, and there was little other obvious retinal damage. CONCLUSIONS A sensitive negative component is reduced or absent from the dark-adapted ERGs of macaque monkeys with severe visual field defects and substantial retinal ganglion cell loss as a consequence of long-standing ocular hypertension.
TL;DR: In this paper, the authors investigated the entry-mode selection activities of small and medium-sized service firms and found that ownership and locational advantages influence the entrymode choice of small-and medium-size firms in a manner similar to that of larger firms.
TL;DR: Long-term cannabis use was associated with disruption of short-term memory, working memory, and attentional skills in older long-term Cannabis users.
Abstract: Background: Cognitive correlates of long-term cannabis use have been elusive. We tested the hypothesis that long-term cannabis use is associated with deficits in shortterm memory, working memory, and attention in a literate, westernized culture (Costa Rica) in which the effects of cannabis use can be isolated. Methods: Two cohorts of long-term cannabis users and nonusers were studied. Within each cohort, users and nonusers were comparable in age and socioeconomic status. Polydrug users and users who tested positive for the use of cannabis at the time of cognitive assessment after a 72-hour abstention period were excluded. The older cohort (whose age was ~45 years) had consumed cannabis for an average of 34 years, and comprised 17 users and 30 nonusers, who had been recruited in San Jose, Costa Rica, and had been observed since 1973. The younger cohort (whose age was ~28 years) had consumed cannabis for an average of 8 years, and comprised 37 users and 49 nonusers. Short-term memory, working memory, and attentional skills were measured in each subject. Results: Older long-term users performed worse than older nonusers on 2 short-term memory tests involving learning lists of words. In addition, older long-term users performed worse than older nonusers on selective and divided attention tasks associated with working memory. No notable differences were apparent between younger users and nonusers. Conclusion: Long-term cannabis use was associated with disruption of short-term memory, working memory, and attentional skills in older long-term cannabis users.