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Showing papers by "University of Virginia published in 1996"


Journal ArticleDOI
TL;DR: In this article, the FIGARCH (Fractionally Integrated Generalized AutoRegressive Conditionally Heteroskedastic) process is introduced and the conditional variance of the process implies a slow hyperbolic rate of decay for the influence of lagged squared innovations.

2,274 citations


Journal ArticleDOI
18 Sep 1996-JAMA
TL;DR: RHC was associated with increased mortality and increased utilization of resources, and these findings justify reconsideration of a randomized controlled trial of RHC and may guide patient selection for such a study.
Abstract: Objective —To examine the association between the use of right heart catheterization (RHC) during the first 24 hours of care in the intensive care unit (ICU) and subsequent survival, length of stay, intensity of care, and cost of care Design —Prospective cohort study Setting —Five US teaching hospitals between 1989 and 1994 Subjects —A total of 5735 critically ill adult patients receiving care in an ICU for 1 of 9 prespecified disease categories Main Outcome Measures —Survival time, cost of care, intensity of care, and length of stay in the ICU and hospital, determined from the clinical record and from the National Death Index A propensity score for RHC was constructed using multivariable logistic regression Case-matching and multivariable regression modeling techniques were used to estimate the association of RHC with specific outcomes after adjusting for treatment selection using the propensity score Sensitivity analysis was used to estimate the potential effect of an unidentified or missing covariate on the results Results —By case-matching analysis, patients with RHC had an increased 30-day mortality (odds ratio, 124; 95% confidence interval, 103-149) The mean cost (25th, 50th, 75th percentiles) per hospital stay was $49300 ($17000, $30500, $56600) with RHC and $35700 ($11 300, $20600, $39200) without RHC Mean length of stay in the ICU was 148 (5,9, 17) days with RHC and 130 (4,7, 14) days without RHC These findings were all confirmed by multivariable modeling techniques Subgroup analysis did not reveal any patient group or site for which RHC was associated with improved outcomes Patients with higher baseline probability of surviving 2 months had the highest relative risk of death following RHC Sensitivity analysis suggested that a missing covariate would have to increase the risk of death 6-fold and the risk of RHC 6-fold for a true beneficial effect of RHC to be misrepresented as harmful Conclusion —In this observational study of critically ill patients, after adjustment for treatment selection bias, RHC was associated with increased mortality and increased utilization of resources The cause of this apparent lack of benefit is unclear The results of this analysis should be confirmed in other observational studies These findings justify reconsideration of a randomized controlled trial of RHC and may guide patient selection for such a study

1,986 citations


01 Jan 1996
TL;DR: Three general approaches to the role of feelings in human cognition focus on the experiential, cognitive, and somatic components of feelings, respectively as mentioned in this paper, and they focus on basic theoretical principles and empirical regularities, rather than complete coverage of the literature.
Abstract: Following an initial emphasis on " cold " cognitive processes, which could be conceptualized within the computer metaphor of the information processing paradigm, social cognition researchers rediscovered " hot " cognition in the 1980's. Two decades later, their interest in the interplay of feeling and thinking is shared by researchers in decision making, cognitive psychology, and related fields. This chapter reviews what has been learned; it focuses on basic theoretical principles and empirical regularities, rather than complete coverage of the literature. We first introduce three broad approaches to the interface of feeling and thinking and subsequently evaluate them in light of empirical findings in three key domains, namely, human judgment, strategies of information processing, and memory. Throughout, we emphasize the influence of feelings on cognitive processes; the reverse influence of cognition on emotion is Three general approaches to the role of feelings in human cognition focus on the experiential, cognitive, and somatic components of feelings, respectively. The first approach emphasizes the experiential quality of feelings and addresses their informational functions. A second approach emphasizes the thoughts that accompany feelings, whereas a third approach emphasizes hard-wired processes, focusing on the somatic components of affective states. Central to the experiential approach is the assumption that feelings can serve as a source of information in their own right. This assumption is consistent with traditional theorizing on emotions and has been fruitfully extended to other subjective experiences. Social psychologists often subsume moods and emotions under the generic term affect. This term, however, can also refer simply to valence-the positive and negative aspect of things. All emotions are affective, but not all affective things are emotions. Emotions arise in response to ongoing, implicit appraisals of situations with respect to positive or negative implications for one's goals and concerns (e. have an identifiable referent (what the emotion is "about"), a sharp rise time, limited duration, and often high intensity. Emotion researchers commonly assume that "emotions exist for the Feelings-2 sake of signaling states of the world that have to be responded to, or that no longer need response and action" (Frijda, 1988, p. 354). What exactly emotions signal can be derived from their underlying appraisal patterns. Sadness, for example, signals a loss or lack of reward that is not attributed to the causal action of another agent; when it is attributed to the causal action of another agent, it gives rise to anger. Accordingly, sadness and …

1,671 citations


Journal ArticleDOI
TL;DR: Participants said that they did not regard their lies as serious and did not plan them much or worry about being caught, still, social interactions in which lies were told were less pleasant and less intimate than those in which no lie was told.
Abstract: In 2 diary studies of lying, 77 college students reported telling 2 lies a day, and 70 community members told 1. Participants told more self-centered lies than other-oriented lies, except in dyads involving only women, in which other-oriented lies were as common as self-centered ones. Participants told relatively more self-centered lies to men and relatively more other-oriented lies to women. Consistent with the view of lying as an everyday social interaction process, participants said that they did not regard their lies as serious and did not plan them much or worry about being caught. Still, social interactions in which lies were told were less pleasant and less intimate than those in which no lies were told.

1,296 citations


Book
01 Jan 1996
TL;DR: The Lekhnitskii Formalism as discussed by the authors is a generalization of the Stroh Formulism for linear anisotropic elasticity matrices with an elliptic boundary.
Abstract: 1. Matrix Algebra 2. Linear Anisotropic Elastic Materials 3. Antiplane Deformations 4. The Lekhnitskii Formalism 5. The Stroh Formalism 6. The Structures and Identities of the Elasticity Matrices 7. Transformation of the Elasticity Matrices and Dual Coordinate Systems 8. Green's Functions for Infinite Space, Half-space, and Composite Space 9. Particular Solutions, Stress Singularities, and Stress Decay 10. Anisotropic Matrials with an Elliptic Boundary 11. Anisotropic Media with a Crack or a Rigid Line Inclusion 12. Steady State Motion and Surface Waves 13. Degenerate and Near Degenerate Materials 14. Generalization of the Stroh Formulism 15. Three-Dimensionsal Deformations

1,250 citations


Journal ArticleDOI
TL;DR: In this paper, a new class of fractionally integrated GARCH and EGARCH models for characterizing financial market volatility is discussed, and Monte Carlo simulations illustrate the reliability of quasi maximum likelihood estimation methods, standard model selection criteria, and residual-based portmanteau diagnostic tests in this context.

1,245 citations


Journal ArticleDOI
TL;DR: Aluminum alloys have been the primary material of choice for structural components of aircraft since about 1930 as discussed by the authors and have been used extensively in high-performance military aircraft and are being specified for some applications in modern commercial aircraft, including the fuselage, wing, and supporting structure of commercial airliners and military cargo and transport.

1,077 citations


Journal ArticleDOI
TL;DR: Findings highlight gender-specific maturational changes of the developing brain and the need for large gender-matched samples in pediatric neuropsychiatric studies.
Abstract: Brain magnetic resonance images (MRI) of 104 healthy children and adolescents, aged 4-18, showed significant effects of age and gender on brain morphometry! Males had larger cerebral (9%) and cerebellar (8%) volumes (P = 0.01 and 0.0001, respectively). In contrast, the cerebral hemispheres and caudate showed a highly consistent rightgreater-than-left asymmetry [P < 00001 for both). All volumes demonstrated a high degree of variability. These findings highlight gender-specific maturational changes of the developing brain and the need for large gender-matched samples in pediatric neuropsychiatric studies.

996 citations


Journal ArticleDOI
TL;DR: In this article, a short channel High Electron Mobility Transistor (HEMT) has a resonance response to electromagnetic radiation at the plasma oscillation frequencies of the two dimensional electrons in the device.
Abstract: We show that a short channel High Electron Mobility Transistor (HEMT) has a resonance response to electromagnetic radiation at the plasma oscillation frequencies of the two dimensional electrons in the device. This response can be used for new types of detectors, mixers, and multipliers. These devices should operate at much higher frequencies than conventional, transit-time limited devices, since the plasma waves propagate much faster than electrons. The responsivities of such devices may greatly exceed the responsivities of Schottky diodes currently used as detectors and mixers in the terahertz range. A long channel HEMT has a nonresonant response to electromagnetic radiation and can be used as a broadband detector for frequencies up to several tens of terahertz.

986 citations


Journal ArticleDOI
19 Apr 1996-Science
TL;DR: Cultured neural retinas of the golden hamster exhibited circadian rhythms of melatonin synthesis for at least 5 days at 27°C, and retinas from hamsters homozygous for the circadian mutation tau showed a shortened free-running period ofmelatonin synthesis.
Abstract: Many retinal functions are circadian, but in most instances the location of the clock that drives the rhythm is not known. Cultured neural retinas of the golden hamster (Mesocricetus auratus) exhibited circadian rhythms of melatonin synthesis for at least 5 days at 27 degrees celsius. The rhythms were entrained by light cycles applied in vitro and were free-running in constant darkness. Retinas from hamsters homozygous for the circadian mutation tau, which shortens the free-running period of the circadian activity rhythm by 4 hours, showed a shortened free-running period of melatonin synthesis. The mammalian retina contains a genetically programmed circadian oscillator that regulates its synthesis of melatonin.

703 citations


Journal ArticleDOI
TL;DR: It follows almost as imme- diately, by "smashing" arguments, that the adjoint is given by tensor product with a dualising complex as mentioned in this paper, which is an immediate consequence of Brown's representability theorem.
Abstract: Grothendieck proved that if f: X ) Y is a proper morphism of nice schemes, then Rf* has a right adjoint, which is given as tensor product with the relative canonical bundle. The original proof was by patching local data. Deligne proved the existence of the adjoint by a global argument, and Verdier showed that this global adjoint may be computed locally. In this article we show that the existence of the adjoint is an immediate consequence of Brown's representability theorem. lIt follows almost as imme- diately, by "smashing" arguments, that the adjoint is given by tensor product with a dualising complex. Verdier's base change theorem is an easy conse- quence. DEPARTMENT OF MATHEMATICS, UNIVERSITY OF VIRGINIA, CHARLOTTESVILLE, VIRGINIA 22903 E-mail address: an3rQvirginia. edu This content downloaded from 157.55.39.27 on Wed, 07 Sep 2016 06:26:19 UTC All use subject to http://about.jstor.org/terms


Journal ArticleDOI
TL;DR: The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated.
Abstract: With the advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated.

Journal ArticleDOI
TL;DR: The complex I defect in PD appears to be genetic, arising from mitochondrial DNA, and may play an important role in the neurodegeneration of PD by fostering reactive oxygen species production and conferring increased neuronal susceptibility to mitochondrial toxins.
Abstract: The mitochondrial electron transport enzyme NADH:ubiquinone oxidoreductase (complex I), which is encoded by both mitochondrial DNA and nuclear DNA, is defective in multiple tissues in persons with Parkinson's disease (PD). The origin of this lesion and its role in the neurodegeneration of PD are unknown. To address these questions, we created an in vitro system in which the potential contributions of environmental toxins, complex I nuclear DNA mutations, and mitochondrial DNA mutations could be systematically analyzed. A clonal line of human neuroblastoma cells containing no mitochondrial DNA was repopulated with mitochondria derived from the platelets of PD or control subjects. After 5 to 6 weeks in culture, these cytoplasmic hybrid (cybrid) cell lines were assayed for electron transport chain activities, production of reactive oxygen species, and sensitivity to induction of apoptotic cell death by 1-methyl-4-phenyl pyridinium (MPP+). In PD cybrids we found a stable 20% decrement in complex I activity, increased oxygen radical production, and increased susceptibility to 1-methyl-4-phenyl pyridinium-induced programmed cell death. The complex I defect in PD appears to be genetic, arising from mitochondrial DNA, and may play an important role in the neurodegeneration of PD by fostering reactive oxygen species production and conferring increased neuronal susceptibility to mitochondrial toxins.


Journal ArticleDOI
TL;DR: It is concluded that the wall of skeletal muscle capillaries is decorated with a 0.4- to 0.5-microns-thick endothelial surface coat, which may represent the true active interface between blood and the capillary wall.
Abstract: A thick endothelial surface coat consisting of the glycocalyx and associated plasma proteins has been hypothesized to reduce functional capillary volume available for flowing plasma macromolecules and blood cells. The purpose of this study was to compare anatomic and functional capillary diameters available for macromolecules, RBCs, and WBCs in hamster cremaster muscle capillaries. Bright-field and fluorescence microscopy provided similar estimates (mean +/- SE) of the anatomic capillary diameter: 5.1 +/- 0.1 microns (bright field, 39 capillaries in 10 animals) and 5.1 +/- 0.2 microns (membrane dye PKH26, 18 capillaries in 2 animals). Estimates of functional diameters were obtained by measuring the width of RBCs and WBCs and the intracapillary distribution of systemically injected fluorescein isothiocyanate (FITC)-dextran 70. WBCs (5.1 +/- 0.2 microns) fully occupied the anatomic capillary cross section. In contrast, the widths of RBCs (3.9 +/- 0.2 microns, 21 capillaries in 8 animals) and FITC-dextran (4.3 +/- 0.2 microns, 21 capillaries in 8 animals) were significantly smaller than the anatomic capillary diameter. Continuous (1- to 5-minute) excitation of fluorochromes in the capillary lumen (light-dye treatment) increased the width of RBCs passing the treated site from 3.6 +/- 0.3 to 4.4 +/- 0.3 microns (6 capillaries in 4 animals) and the width of the FITC-dextran column from 4.1 +/- 0.2 to 4.6 +/- 0.3 microns (10 capillaries in 7 animals). Furthermore, light-dye treatment increased capillary tube hematocrit by 60% in 40-microns-long capillary segments compared with untreated sites in the same capillaries. It is concluded that the wall of skeletal muscle capillaries is decorated with a 0.4- to 0.5-microns-thick endothelial surface coat, which may represent the true active interface between blood and the capillary wall.

Journal ArticleDOI
TL;DR: Evidence now suggests that a triggered conformational change that exposes a previously cryptic fusion peptide, along with a rearrangement of the fusion protein oligomer, allows the fusion peptides to gain access to the target bilayer and thus initiate the fusion reaction.
Abstract: Significant progress has been made in elucidating the mechanisms of viral membrane fusion proteins; both those that function at low, as well as those that function at neutral, pH. For many viral fusion proteins evidence now suggests that a triggered conformational change that exposes a previously cryptic fusion peptide, along with a rearrangement of the fusion protein oligomer, allows the fusion peptide to gain access to the target bilayer and thus initiate the fusion reaction. Although the topologically equivalent process of cell-cell fusion is less well understood, several cell surface proteins, including members of the newly described ADAM gene family, have emerged as candidate adhesion/fusion proteins.

Journal ArticleDOI
TL;DR: In this paper, the authors distinguished between violent offenders with a history of at least 1 instrumental violent offense and those who committed reactive violent offenses, and found that instrumental offenders would score higher than reactive offenders and nonviolent offenders on R. D. Hare's psychopathy checklist.
Abstract: Can violent offenders who commit acts of instrumental aggression for goal-oriented purposes such as robbery be distinguished from those who commit acts of reactive (or hostile) aggression in response to provocation? Because violent offenders often have a history of both instrumental and reactive aggression, this study distinguished between offenders with a history of at least 1 instrumental violent offense and offenders with a history of reactive violent offenses. Two studies tested the hypothesis that instrumental offenders would score higher than reactive offenders and nonviolent offenders on R. D. Hare's (1991) Psychopathy Checklist. The first study sample consisted of 106 violent and nonviolent offenders recruited from a medium-security correctional facility. The second study sample consisted of 50 violent offenders referred for pretrial forensic evaluation. In both samples, instrumental offenders could be reliably distinguished from reactive offenders on the basis of violent crime behavior and level of psychopathy. Group differences could not be attributed to participant age, race, length of incarceration, or extent of prior criminal record.

Journal ArticleDOI
25 Jul 1996-Nature
TL;DR: It is reported that, in mice deficient for the β7 integrin subfamily of adhesion molecules, the formation of the GALT is severely impaired, probably due to a failure of β7–/– lymphocytes to arrest and adhere to the vasculature at the site of transmigration into the Galt.
Abstract: Immune defence against pathogens entering the gut is accomplished by lymphocytes in the gut-associated lymphoid tissue (GALT), a major compartment of the immune system. The GALT, comprising Peyer's patches, lamina propria lymphocytes and intra-epithelial lymphocytes of the intestine, is populated by lymphocytes that migrate there from the vasculature. Here we report that, in mice deficient for the beta7 integrin subfamily of adhesion molecules, the formation of the GALT is severely impaired. This is probably due to a failure of beta7-/- lymphocytes to arrest and adhere to the vasculature at the site of transmigration into the GALT.

Journal ArticleDOI
TL;DR: The results indicate that customized neural networks offer a very promising avenue for building effective generic models if the measure of performance is percentage of bad loans correctly classified, but logistic regression models are comparable to the neural networks approach.


Journal ArticleDOI
TL;DR: The clinical manifestations of leishmaniasis depend on interactions between the virulence characteristics of the infecting Leishmania species and the immune responses of its host, resulting in a spectrum of disease ranging from localized skin lesions to diffuse involvement of the reticuloendothelial system.
Abstract: The clinical manifestations of leishmaniasis depend on com­ plex interactions between the virulence characteristics of the infecting Leishmania species and the immune responses of its host. The result is a spectrum of disease ranging from localized skin lesions to diffuse involvement of the reticuloendothelial system. Human disease has traditionally been divided into three major clinical syndromes: visceral, cutaneous, and mucosal leishmaniasis; however, a number of variants exist. Further­ more, a single Leishmania species can produce more than one clinical syndrome, and each syndrome is caused by multiple species. The true incidence and prevalence of leishmaniasis is uncer­ tain because many cases go undiagnosed or unreported in areas where the infection is endemic. In 1993, the World Health Organization estimated that 350 million people worldwide were at risk for infection. The incidence of cutaneous leishmaniasis has been estimated to be 1.0-1.5 million cases per year, and

Journal ArticleDOI
11 Apr 1996-Nature
TL;DR: It is proposed that pp41/43FRNK functions as an endogenous regulator of pp125FAK, thus providing an unusual means to regulate both tyrosine kinase activity and cellular adhesion to the extracellular matrix.
Abstract: FOCAL adhesion kinase1,2 (pp125FAK) is a member of a growing family of structurally distinct protein tyrosine kinases that includes the recently identified FakB3 and PYK2/CAKβ/ RAFTK4,6. Activation of pp125FAK has been functionally linked to the formation of focal adhesions, integrin-mediated sites of contact between the cell and the extracellular matrix7,8. The carboxy-terminal domain of pp125FAK is also expressed as a separate protein called pp41/43FRNK(where FRNK represents pp125FAK-related non-kinase)9. Here we show that pp41/43FRNK acts as an inhibitor of pp125FAK by transiently blocking the formation of focal adhesions on fibronectin and constitutively reducing tyrosine phosphorylation of both pp125FAK and of two focal adhesion proteins, tensin and paxillin. These inhibitory effects of pp41/43FRNK are reversed by co-expression of pp!25FAK, suggesting that pp125FAK and pp41/43FRNK compete for a common binding protein(s) whose association with pp125FAK is necessary for signalling by pp125FAK. We propose that pp41/43FRNK functions as an endogenous regulator of pp125FAK, thus providing an unusual means to regulate both tyrosine kinase activity and cellular adhesion to the extracellular matrix.

Journal ArticleDOI
TL;DR: It is reported that Tup1 directly interacts with the amino-terminal tails of histones H3 and H4, providing a molecular basis for this connection and suggesting a mechanism whereby the organization of chromatin may be modulated in response to changing environmental signals.
Abstract: Repression of yeast a cell-specific genes by the global repressor Ssn6lTupl has been linked to a specific organization of chromatin. We report here that Tupl directly interacts with the amino-terminal tails of histones H3 and H4, providing a molecular basis for this connection. This interaction appears to be required for Tupl function because amino-terminal mutations in H3 and H4 that weaken interactions with Tupl cause derepression of both a cell-specific and DNA damage-inducible genes. Moreover, the Tupl histone-binding domain coincides with the previously defined Tupl repression domain. Tupllhistone interactions are negatively influenced by high levels of histone acetylation, suggesting a mechanism whereby the organization of chromatin may be modulated in response to changing environmental signals.

Journal ArticleDOI
18 Jan 1996-Nature
TL;DR: The shear threshold requirement for L-selectin may be physiologically important in low shear to prevent inappropriate aggregation of leukocytes and interaction with the vessel wall.
Abstract: Selectins are cell adhesion molecules that bind carbohydrate ligands and promote interaction between leukocytes and the vessel wall in vascular shear flow. Selectin-ligand bonds have high mechanical strength, allowing initial tethering to the vessel wall through one or few bonds, and have fast on and off rates, permitting rolling in response to hydrodynamic drag. The L-selectin molecule on leukocytes binds to peripheral node addressin on high endothelial venules of lymph nodes to mediate leukocyte rolling and binds to a ligand on neutrophils to mediate rolling of leukocytes over one another. Here we describe a surprising mechanism for regulation of these interactions, both in vitro and in vivo. Shear above a critical threshold is required to promote and maintain rolling interactions through L-selectin, but not through E-selectin, P-selectin or VCAM-1. The shear threshold requirement for L-selectin may be physiologically important in low shear to prevent inappropriate aggregation of leukocytes and interaction with the vessel wall.

Journal ArticleDOI
TL;DR: Microsatellite instability in the insulin–like growth factor II receptor gene in gastrointestinal tumours is found to be a major cause of uncertainty in the prognosis of these tumours.
Abstract: Microsatellite instability in the insulin–like growth factor II receptor gene in gastrointestinal tumours


Journal ArticleDOI
TL;DR: It is shown that for both binary and analog neurons, increased energy expenditure per neuron implies a decrease in average firing rate if energy efficient information transmission is to be maintained.
Abstract: In 1969 Barlow introduced the phrase “economy of impulses” to express the tendency for successive neural systems to use lower and lower levels of cell firings to produce equivalent encodings. From this viewpoint, the ultimate economy of impulses is a neural code of minimal redundancy. The hypothesis motivating our research is that energy expenditures, e.g., the metabolic cost of recovering from an action potential relative to the cost of inactivity, should also be factored into the economy of impulses. In fact, coding schemes with the largest representational capacity are not, in general, optimal when energy expenditures are taken into account. We show that for both binary and analog neurons, increased energy expenditure per neuron implies a decrease in average firing rate if energy efficient information transmission is to be maintained.

Journal ArticleDOI
25 Sep 1996-JAMA
TL;DR: Prevalence of Alzheimer disease in older Japanese-American men in Hawaii appears to be higher than in Japan but similar to European-ancestry populations.
Abstract: Objective. —To determine prevalence of dementia and its subtypes in Japanese-American men and compare these findings with rates reported for populations in Japan and elsewhere. Design and Setting. —The Honolulu Heart Program is a prospective populationbased study of cardiovascular disease established in 1965. Prevalence estimates were computed from cases identified at the 1991 to 1993 examination. Cognitive performance was assessed using standardized methods, instruments, and diagnostic criteria. Participants. —Subjects were 3734 Japanese-American men (80% of surviving cohort) aged 71 through 93 years, living in the community or in institutions. Main Outcome Measures. —Age-specific, age-standardized, and cohort prevalence estimates were computed for dementia (all cause) defined by 2 sets of diagnostic criteria and 4 levels of severity. Prevalence levels for Alzheimer disease and vascular dementia were also estimated. Results. —Dementia prevalence byDiagnostic and Statistical Manual of Mental Disorders, Third Edition, Revisedranged from 2.1% in men aged 71 through 74 years to 33.4% in men aged 85 through 93 years. Age-standardized prevalence was 7.6%. Prevalence estimates for the cohort were 9.3% for dementia (all cause), 5.4% for Alzheimer disease (primary or contributing), and 4.2% for vascular dementia (primary or contributing). More than 1 possible cause was found in 26% of cases. The Alzheimer disease/vascular dementia ratio was 1.5 for cases attributed primarily to Alzheimer disease or vascular dementia. Conclusions. —Prevalence of Alzheimer disease in older Japanese-American men in Hawaii appears to be higher than in Japan but similar to European-ancestry populations. Prevalence of vascular dementia appears to be only slightly lower than in Japan, but higher than in European-ancestry populations. Further cross-national research with emphasis on standardized diagnostic methods is needed.

Journal ArticleDOI
TL;DR: The diagnostic boundaries of the behavioural phenotype for autism were examined in 28 MZ pairs and 20 DZ same-sex twin pairs, where one or both twins had autism.
Abstract: The diagnostic boundaries of the behavioural phenotype for autism were examined in 28 MZ pairs and 20 DZ same-sex twin pairs, where one or both twins had autism. In the non-autistic cotwin (i.e. in twin pairs discordant for autism) it was common to find language impairments in childhood and social deficits persisting into adulthood. Concordance for this broader phenotype was much greater in MZ pairs than DZ pairs, indicating a strong genetic component. Behavioural and cognitive manifestations of autism were compared both within and between MZ twin pairs. The variation was as great within MZ twin pairs as between pairs, suggesting that it does not index genetic heterogeneity (although aetiological heterogeneity probably exists). Current diagnostic practices need re-evaluation.