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A critical discussion is given of the use of local compositions for representation of excess Gibbs energies of liquid mixtures. A new equation is derived, based on Scott's two-liquid model and on an assumption of nonrandomness similar to that used by Wilson. For the same activity coefficients at infinite dilution, the Gibbs energy of mixing is calculated with the new equation as well as the equations of van Laar, Wilson, and Heil; these four equations give similar results for mixtures of moderate nonideality but they differ appreciably for strongly nonideal systems, especially for those with limited miscibility. The new equation contains a nonrandomness parameter α12 which makes it applicable to a large variety of mixtures. By proper selection of α12, the new equation gives an excellent representation of many types of liquid mixtures while other local composition equations appear to be limited to specific types. Consideration is given to prediction of ternary vapor-liquid and ternary liquid-liquid equilibria based on binary data alone.

1996 - Genetics

Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data.

When a population experiences a reduction of its effective size, it generally develops a heterozygosity excess at selectively neutral loci, i.e., the heterozygosity computed from a sample of genes is larger than the heterozygosity expected from the number of alleles found in the sample if the population were at mutation drift equilibrium. The heterozygosity excess persists only a certain number of generations until a new equilibrium is established. Two statistical tests for detecting a heterozygosity excess are described. They require measurements of the number of alleles and heterozygosity at each of several loci from a population sample. The first test determines if the proportion of loci with heterozygosity excess is significantly larger than expected at equilibrium. The second test establishes if the average of standardized differences between observed and expected heterozygosities is significantly different from zero. Type I and II errors have been evaluated by computer simulations, varying sample size, number of loci, bottleneck size, time elapsed since the beginning of the bottleneck and level of variability of loci. These analyses show that the most useful markers for bottleneck detection are those evolving under the infinite allele model (IAM) and they provide guidelines for selecting sample sizes of individuals and loci. The usefulness of these tests for conservation biology is discussed.

1975 - Aiche Journal

Statistical thermodynamics of liquid mixtures: A new expression for the excess Gibbs energy of partly or completely miscible systems

To obtain a semi-theoretical equation for the excess Gibbs energy of a liquid mixture, Guggenheim's quasi-chemical analysis is generalized through introduction of the local area fraction as the primary concentration variable. The resulting universal quasi-chemical (UNIQUAC) equation uses only two adjustable parameters per binary. Extension to multicomponent systems requires no ternary (or higher) parameters. The UNIQUAC equation gives good representation of both vapor-liquid and liquid-liquid equilibria for binary and multicomponent mixtures containing a variety of nonelectrolyte components such as hydrocarbons, ketones, esters, amines, alcohols, nitriles, etc., and water. When well-defined simplifying assumptions are introduced into the generalized quasi-chemical treatment, the UNIQUAC equation reduces to any one of several well-known equations for the excess Gibbs energy, including the Wilson, Margules, van Laar, and NRTL equations. The effects of molecular size and shape are introduced through structural parameters obtained from pure-component data and through use of Staverman's combinatorial entropy as a boundary condition for athermal mixtures. The UNIQUAC equation, therefore, is applicable also to polymer solutions.


Energy detection of unknown deterministic signals

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By using Shannon's sampling formula, the problem of the detection of a deterministic signal in white Gaussian noise, by means of an energy-measuring device, reduces to the consideration of the sum of the squares of statistically independent Gaussian variates. When the signal is absent, the decision statistic has a central chi-square distribution with the number of degrees of freedom equal to twice the time-bandwidth product of the input. When the signal is present, the decision statistic has a noncentral chi-square distribution with the same number of degrees of freedom and a noncentrality parameter λ equal to the ratio of signal energy to two-sided noise spectral density. Since the noncentral chi-square distribution has not been tabulated extensively enough for our purpose, an approximate form was used. This form replaces the noncentral chi-square with a modified chi-square whose degrees of freedom and threshold are determined by the noncentrality parameter and the previous degrees of freedom. Sets of receiver operating characteristic (ROC) curves are drawn for several time-bandwidth products, as well as an extended nomogram of the chi-square cumulative probability which can be used for rapid calculation of false alarm and detection probabilities. Related work in energy detection by J. I. Marcum and E. L Kaplan is discussed.


Predicting Excess Stock Returns Out of Sample: Can Anything Beat the Historical Average?

Goyal and Welch (2007) argue that the historical average excess stock return forecasts future excess stock returns better than regressions of excess returns on predictor variables. In this article, we show that many predictive regressions beat the historical average return, once weak restrictions are imposed on the signs of coefficients and return forecasts. The out-of-sample explanatory power is small, but nonetheless is economically meaningful for mean-variance investors. Even better results can be obtained by imposing the restrictions of steady-state valuation models, thereby removing the need to estimate the average from a short sample of volatile stock returns.


Overconfidence and Excess Entry: An Experimental Approach

Psychological studies show that most people are overconfident about their own relative abilities, and unreasonably optimistic about their futures (e.g. Shelly E. Taylor and J.D. Brown, 1988; Neil D. Weinstein, 1980). When assessing their position in a distribution of peers on almost any positive trait-- like driving ability (Ola Svenson, 1981 ), income prospects, or longevity-- a vast majority of people say they are above the average, although of course, only half can be (if the trait is symmetrically distributed). This paper explores whether optimistic biases could plausibly and predictably influence economic behavior in one particular setting-- entry into competitive games or markets. Many empirical studies show that most new businesses fail within a few years. For example, using plant level data from the U.S. Census of Manufacturers spanning 1963-1982, Timothy Dunne et al. (1988) estimated that 61.5 percent of all entrants exited within five years and 79.6 percent exited within 10 years. Most of these exits are failures (see also Dunne et al., 1989a, 1989b; D. Shapiro and R.S. Khemani, 1987).


Assessing the Dimensionality and Structure of the Consumption Experience: Evaluation, Feeling, and Satisfaction

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This article examines the underlying dimensionality of three aspects of the post-consumption experience—product evaluation, product-elicited affect, and product satisfaction. In addition, the article integrates these concepts through a suggested causal framework. Students evaluated either a high- or a low-involvement product in current use, reported affective responses evoked by it, and assessed their levels of product-derived satisfaction. Analysis shows that two primary dimensions of product evaluation—utilitarian and hedonic judgment—can be viewed as causally antecedent to two dimensions of affect—pleasantness and arousal—and to product satisfaction. Implications of the conceptual framework and empirical findings for the study of consumption events are discussed.

2005 - JAMA

Excess deaths associated with underweight, overweight, and obesity.

CONTEXT As the prevalence of obesity increases in the United States, concern over the association of body weight with excess mortality has also increased. OBJECTIVE To estimate deaths associated with underweight (body mass index [BMI] <18.5), overweight (BMI 25 to <30), and obesity (BMI > or =30) in the United States in 2000. DESIGN, SETTING, AND PARTICIPANTS We estimated relative risks of mortality associated with different levels of BMI (calculated as weight in kilograms divided by the square of height in meters) from the nationally representative National Health and Nutrition Examination Survey (NHANES) I (1971-1975) and NHANES II (1976-1980), with follow-up through 1992, and from NHANES III (1988-1994), with follow-up through 2000. These relative risks were applied to the distribution of BMI and other covariates from NHANES 1999-2002 to estimate attributable fractions and number of excess deaths, adjusted for confounding factors and for effect modification by age. MAIN OUTCOME MEASURES Number of excess deaths in 2000 associated with given BMI levels. RESULTS Relative to the normal weight category (BMI 18.5 to <25), obesity (BMI > or =30) was associated with 111,909 excess deaths (95% confidence interval [CI], 53,754-170,064) and underweight with 33,746 excess deaths (95% CI, 15,726-51,766). Overweight was not associated with excess mortality (-86,094 deaths; 95% CI, -161,223 to -10,966). The relative risks of mortality associated with obesity were lower in NHANES II and NHANES III than in NHANES I. CONCLUSIONS Underweight and obesity, particularly higher levels of obesity, were associated with increased mortality relative to the normal weight category. The impact of obesity on mortality may have decreased over time, perhaps because of improvements in public health and medical care. These findings are consistent with the increases in life expectancy in the United States and the declining mortality rates from ischemic heart disease.

1996 - astro-ph/9603033

A Line of sight integration approach to cosmic microwave background anisotropies

We present a new method for calculating linear cosmic microwave background (CMB) anisotropy spectra based on integration over sources along the photon past light cone. In this approach the temperature anisotropy is written as a time integral over the product of a geometrical term and a source term. The geometrical term is given by radial eigenfunctions which do not depend on the particular cosmological model. The source term can be expressed in terms of photon, baryon and metric perturbations, all of which can be calculated using a small number of differential equations. This split clearly separates between the dynamical and geometrical effects on the CMB anisotropies. More importantly, it allows to significantly reduce the computational time compared to standard methods. This is achieved because the source term, which depends on the model and is generally the most time consuming part of calculation, is a slowly varying function of wavelength and needs to be evaluated only in a small number of points. The geometrical term, which oscillates much more rapidly than the source term, does not depend on the particular model and can be precomputed in advance. Standard methods that do not separate the two terms and require a much higher number of evaluations. The new method leads to about two orders of magnitude reduction in CPU time when compared to standard methods and typically requires a few minutes on a workstation for a single model. The method should be especially useful for accurate determinations of cosmological parameters from CMB anisotropy and polarization measurements that will become possible with the next generation of experiments. A programm implementing this method can be obtained from the authors.

2011 - NBER Working Paper Series

Credit Spreads and Business Cycle Fluctuations

This paper examines the evidence on the relationship between credit spreads and economic activity. Using an extensive data set of prices of outstanding corporate bonds trading in the secondary market, we construct a credit spread index that is--compared with the standard default-risk indicators--a considerably more powerful predictor of economic activity. Using an empirical framework, we decompose our index into a predictable component that captures the available firm-specific information on expected defaults and a residual component--the excess bond premium. Our results indicate that the predictive content of credit spreads is due primarily to movements in the excess bond premium. Innovations in the excess bond premium that are orthogonal to the current state of the economy are shown to lead to significant declines in economic activity and equity prices. We also show that during the 2007-09 financial crisis, a deterioration in the creditworthiness of broker-dealers--key financial intermediaries in the corporate cash market--led to an increase in the excess bond premium. These find- ings support the notion that a rise in the excess bond premium represents a reduction in the effective risk-bearing capacity of the financial sector and, as a result, a contraction in the supply of credit with significant adverse consequences for the macroeconomy.

2007 - Radiation research

Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998

Preston, D. L., Ron, E., Tokuoka, S., Funamoto, S., Nishi, N., Soda, M., Mabuchi, K. and Kodama, K. Solid Cancer Incidence in Atomic Bomb Survivors: 1958–1998. Radiat. Res. 168, 1–64 (2007). This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki atomic bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, how these risks vary with gender, age at exposure, and attained age, and the evidence for inter-site variation in the levels and patterns of the excess risk. For all solid cancers as a group, it was estimated that about 850 (about 11%) of the cases among cohort members with colon doses in excess of 0.005 Gy were associated with atomic bomb radiation exposure. The data were consistent with a linear dose response over the 0- to 2-Gy range, while there was some flattening of the dose response at higher doses. Furthermore, there is a statistically significant dose response when analyses were limited to cohort members with doses of 0.15 Gy or less. The excess risks for all solid cancers as a group and many individual sites exhibit significant variation with gender, attained age, and age at exposure. It was estimated that, at age 70 after exposure at age 30, solid cancer rates increase by about 35% per Gy (90% CI 28%; 43%) for men and 58% per Gy (43%; 69%) for women. For all solid cancers as a group, the excess relative risk (ERR per Gy) decreases by about 17% per decade increase in age at exposure (90% CI 7%; 25%) after allowing for attained-age effects, while the ERR decreased in proportion to attained age to the power 1.65 (90% CI 2.1; 1.2) after allowing for age at exposure. Despite the decline in the ERR with attained age, excess absolute rates appeared to increase throughout the study period, providing further evidence that radiation-associated increases in cancer rates persist throughout life regardless of age at exposure. For all solid cancers as a group, women had somewhat higher excess absolute rates than men (F:M ratio 1.4; 90% CI 1.1; 1.8), but this difference disappears when the analysis was restricted to non-gender-specific cancers. Significant radiation-associated increases in risk were seen for most sites, including oral cavity, esophagus, stomach, colon, liver, lung, non-melanoma skin, breast, ovary, bladder, nervous system and thyroid. Although there was no indication of a statistically significant dose response for cancers of the pancreas, prostate and kidney, the excess relative risks for these sites were also consistent with that for all solid cancers as a group. Dose–response estimates for cancers of the rectum, gallbladder and uterus were not statistically significant, and there were suggestions that the risks for these sites may be lower than those for all solid cancers combined. However, there was emerging evidence from the present data that exposure as a child may increase risks of cancer of the body of the uterus. Elevated risks were seen for all of the five broadly classified histological groups considered, including squamous cell carcinoma, adenocarcinoma, other epithelial cancers, sarcomas and other non-epithelial cancers. Although the data were limited, there was a significant radiation-associated increase in the risk of cancer occurring in adolescence and young adulthood. In view of the persisting increase in solid cancer risks, the LSS should continue to provide important new information on radiation exposure and solid cancer risks for at least another 15 to 20 years.

2007 - JAMA

Cause-specific excess deaths associated with underweight, overweight, and obesity.

CONTEXT The association of body mass index (BMI) with cause-specific mortality has not been reported for the US population. OBJECTIVE To estimate cause-specific excess deaths associated with underweight (BMI <18.5), overweight (BMI 25-<30), and obesity (BMI > or =30). DESIGN, SETTING, AND PARTICIPANTS Cause-specific relative risks of mortality from the National Health and Nutrition Examination Survey (NHANES) I, 1971-1975; II, 1976-1980; and III, 1988-1994, with mortality follow-up through 2000 (571,042 person-years of follow-up) were combined with data on BMI and other covariates from NHANES 1999-2002 with underlying cause of death information for 2.3 million adults 25 years and older from 2004 vital statistics data for the United States. MAIN OUTCOME MEASURES Cause-specific excess deaths in 2004 by BMI levels for categories of cardiovascular disease (CVD), cancer, and all other causes (noncancer, non-CVD causes). RESULTS Based on total follow-up, underweight was associated with significantly increased mortality from noncancer, non-CVD causes (23,455 excess deaths; 95% confidence interval [CI], 11,848 to 35,061) but not associated with cancer or CVD mortality. Overweight was associated with significantly decreased mortality from noncancer, non-CVD causes (-69 299 excess deaths; 95% CI, -100 702 to -37 897) but not associated with cancer or CVD mortality. Obesity was associated with significantly increased CVD mortality (112,159 excess deaths; 95% CI, 87,842 to 136,476) but not associated with cancer mortality or with noncancer, non-CVD mortality. In further analyses, overweight and obesity combined were associated with increased mortality from diabetes and kidney disease (61 248 excess deaths; 95% CI, 49 685 to 72,811) and decreased mortality from other noncancer, non-CVD causes (-105,572 excess deaths; 95% CI, -161 816 to -49,328). Obesity was associated with increased mortality from cancers considered obesity-related (13,839 excess deaths; 95% CI, 1920 to 25,758) but not associated with mortality from other cancers. Comparisons across surveys suggested a decrease in the association of obesity with CVD mortality over time. CONCLUSIONS The BMI-mortality association varies by cause of death. These results help to clarify the associations of BMI with all-cause mortality.


Effects of Price, Brand, and Store Information on Buyers’ Product Evaluations:

The authors report a study of the effects of price, brand, and store information on buyers’ perceptions of product quality and value, as well as their willingness to buy. Hypotheses are derived fro...

2014 - Physical review letters

Detection of B-mode polarization at degree angular scales by BICEP2.

We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of ≈300  μK(CMB)√s. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ΛCDM expectation in the range 30 < ℓ < 150, inconsistent with the null hypothesis at a significance of >5σ. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power ∼(5-10)× smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7σ. The observed B-mode power spectrum is well fit by a lensed-ΛCDM+tensor theoretical model with tensor-to-scalar ratio r = 0.20_(-0.05)(+0.07), with r = 0 disfavored at 7.0σ. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets.


Do Long‐Term Shareholders Benefit From Corporate Acquisitions?

Using 947 acquisitions during 1970-89, this article finds a relationship between the postacquisition returns and the mode of acquisition and form of payment. During a five-year period following the acquisition, on average, firms that complete stock mergers earn significantly negative excess returns of -25.0 percent whereas firms that complete cash tender offers earn significantly positive excess returns of 61.7 percent. Over the combined preacquisition and postacquisition period, target shareholders who hold on to the acquirer stock received as payment in stock mergers do not earn significantly positive excess returns. In the top quartile of target to acquirer size ratio, they earn negative excess returns. Copyright 1997 by American Finance Association.

2012 - Nature

The long-range interaction landscape of gene promoters

The vast non-coding portion of the human genome is full of functional elements and disease-causing regulatory variants. The principles defining the relationships between these elements and distal target genes remain unknown. Promoters and distal elements can engage in looping interactions that have been implicated in gene regulation. Here we have applied chromosome conformation capture carbon copy (5C) to interrogate comprehensively interactions between transcription start sites (TSSs) and distal elements in 1% of the human genome representing the ENCODE pilot project regions. 5C maps were generated for GM12878, K562 and HeLa-S3 cells and results were integrated with data from the ENCODE consortium. In each cell line we discovered >1,000 long-range interactions between promoters and distal sites that include elements resembling enhancers, promoters and CTCF-bound sites. We observed significant correlations between gene expression, promoter–enhancer interactions and the presence of enhancer RNAs. Long-range interactions show marked asymmetry with a bias for interactions with elements located ∼120 kilobases upstream of the TSS. Long-range interactions are often not blocked by sites bound by CTCF and cohesin, indicating that many of these sites do not demarcate physically insulated gene domains. Furthermore, only ∼7% of looping interactions are with the nearest gene, indicating that genomic proximity is not a simple predictor for long-range interactions. Finally, promoters and distal elements are engaged in multiple long-range interactions to form complex networks. Our results start to place genes and regulatory elements in three-dimensional context, revealing their functional relationships.


The Moderating Effect of Prior Knowledge on Cue Utilization in Product Evaluations

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This article examines the dissimilar use of product information cues in product evaluations by differentially familiar subjects. Specifically, the use of price cues and intrinsic product cues for the assessment of product quality is hypothesized to depend on prior knowledge. For a product with a positive quality-price association in the marketplace, the study shows that low-familiar and highly familiar subjects tend to perceive a stronger price-quality relationship than do moderately familiar subjects. Moreover, as subjects product familiarity increases, the use of intrinsic cues for product quality assessments tends to become relatively stronger.

2001 - IEEE Trans. Inf. Theory

Analysis of sum-product decoding of low-density parity-check codes using a Gaussian approximation

Density evolution is an algorithm for computing the capacity of low-density parity-check (LDPC) codes under message-passing decoding. For memoryless binary-input continuous-output additive white Gaussian noise (AWGN) channels and sum-product decoders, we use a Gaussian approximation for message densities under density evolution to simplify the analysis of the decoding algorithm. We convert the infinite-dimensional problem of iteratively calculating message densities, which is needed to find the exact threshold, to a one-dimensional problem of updating the means of the Gaussian densities. This simplification not only allows us to calculate the threshold quickly and to understand the behavior of the decoder better, but also makes it easier to design good irregular LDPC codes for AWGN channels. For various regular LDPC codes we have examined, thresholds can be estimated within 0.1 dB of the exact value. For rates between 0.5 and 0.9, codes designed using the Gaussian approximation perform within 0.02 dB of the best performing codes found so far by using density evolution when the maximum variable degree is 10. We show that by using the Gaussian approximation, we can visualize the sum-product decoding algorithm. We also show that the optimization of degree distributions can be understood and done graphically using the visualization.

2014 - The New England journal of medicine

Effects of extended-release niacin with laropiprant in high-risk patients.

BACKGROUND Patients with evidence of vascular disease are at increased risk for subsequent vascular events despite effective use of statins to lower the low-density lipoprotein (LDL) cholesterol level. Niacin lowers the LDL cholesterol level and raises the high-density lipoprotein (HDL) cholesterol level, but its clinical efficacy and safety are uncertain. METHODS After a prerandomization run-in phase to standardize the background statin-based LDL cholesterol-lowering therapy and to establish participants' ability to take extended-release niacin without clinically significant adverse effects, we randomly assigned 25,673 adults with vascular disease to receive 2 g of extended-release niacin and 40 mg of laropiprant or a matching placebo daily. The primary outcome was the first major vascular event (nonfatal myocardial infarction, death from coronary causes, stroke, or arterial revascularization). RESULTS During a median follow-up period of 3.9 years, participants who were assigned to extended-release niacin-laropiprant had an LDL cholesterol level that was an average of 10 mg per deciliter (0.25 mmol per liter as measured in the central laboratory) lower and an HDL cholesterol level that was an average of 6 mg per deciliter (0.16 mmol per liter) higher than the levels in those assigned to placebo. Assignment to niacin-laropiprant, as compared with assignment to placebo, had no significant effect on the incidence of major vascular events (13.2% and 13.7% of participants with an event, respectively; rate ratio, 0.96; 95% confidence interval [CI], 0.90 to 1.03; P=0.29). Niacin-laropiprant was associated with an increased incidence of disturbances in diabetes control that were considered to be serious (absolute excess as compared with placebo, 3.7 percentage points; P<0.001) and with an increased incidence of diabetes diagnoses (absolute excess, 1.3 percentage points; P<0.001), as well as increases in serious adverse events associated with the gastrointestinal system (absolute excess, 1.0 percentage point; P<0.001), musculoskeletal system (absolute excess, 0.7 percentage points; P<0.001), skin (absolute excess, 0.3 percentage points; P=0.003), and unexpectedly, infection (absolute excess, 1.4 percentage points; P<0.001) and bleeding (absolute excess, 0.7 percentage points; P<0.001). CONCLUSIONS Among participants with atherosclerotic vascular disease, the addition of extended-release niacin-laropiprant to statin-based LDL cholesterol-lowering therapy did not significantly reduce the risk of major vascular events but did increase the risk of serious adverse events. (Funded by Merck and others; HPS2-THRIVE number, NCT00461630.).

2000 - The British journal of psychiatry : the journal of mental science

Causes of the excess mortality of schizophrenia.

BACKGROUND The excess mortality of schizophrenia is well recognised, but its precise causes are not well understood. AIMS To measure the standardised mortality ratio (SMR) and examine the reasons for any excess mortality in a community cohort with schizophrenia. METHOD We carried out a 13-year follow-up of 370 patients with schizophrenia, identifying those who died and their circumstances. RESULTS Ninety-six per cent of the cohort was traced. There were 79 deaths. The SMRs for all causes (298), for natural (232) and for unnatural causes (1273), were significantly higher than those to be expected in the general population, as were the SMRs for disease of the circulatory, digestive, endocrine, nervous and respiratory systems, suicide and undetermined death. Smoking-related fatal disease was more prominent than in the general population. CONCLUSIONS Some of the excess mortality of schizophrenia could be lessened by reducing patients' smoking and exposure to other environmental risk factors and by improving the management of medical disease, mood disturbance and psychosis.