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PubMed2002

Variable selection using pair-correlation method. Environmental applications.

Pair-correlation method (PCM) has been developed for selecting between two, correlated descriptor variables. PCM utilizes systematic information present in the scatter of QSAR applications. The data are suitably ordered in a 2 x 2 contingency table. Statistical tests are used to discriminate between the descriptor variables. We have developed, adapted, investigated and compared the following test statistics to each other: Conditional Fisher's exact test (CE), McNemar's test (MN), Chi-square test and Williams' t-test (Wt). If a test indicates significant difference between the descriptors, we use the terms superior-inferior or winner-loser for the overwhelming and subordinate descriptors, respectively. If more than two variables are to be compared, the discrimination can be made pair-wise and then the variables have to be ordered. Three ways of ordering have been used: simple ordering (number of wins), ordering according to the differences between wins and losses, and ordering according to probability-weighted differences between wins and losses. The basic algorithm of PCM has been described in this paper, the various selection criteria and the ordering methods were compared on suitable model systems. These case studies involved description of cAMP phospodiesterase inhibition by flavons, toxicity of chlorobenzenes and mutagenic character of aromatic and heteroaromatic amines.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2006

Neighborhood environmental factors correlated with walking near home: Using SPACES.

PURPOSE: The physical environment plays an important role in influencing participation in physical activity, although the specific factors that are correlated with different patterns of walking remain to be determined. We examined correlations between physical environmental factors and self-reported walking for recreation and transport near home. METHODS: The local neighborhood environments (defined as a 400-m radius from the respondent's home) of 1678 adults were assessed for their suitability for walking. The environmental data were collected during 2000 using the Systematic Pedestrian and Cycling Environmental Scan (SPACES) instrument together with information from other sources. We used logistic regression modeling to examine the relationship between the attributes of the physical environment and the self-reported walking behavior undertaken near home. RESULTS: Functional features were correlated with both walking for recreation (odds ratio (OR) 1.62; 95% confidence interval (CI): 1.20-2.19) and for transport (OR 1.30; 95% CI: 0.97-1.73). A well-maintained walking surface was the main functional factor associated with walking for recreation (OR 2.04; 95% CI: 1.43-2.91) and for transport (OR 2.13; 95% CI: 1.53-2.96). Destination factors, such as shops and public transport, were significantly correlated with walking for transport (OR 1.80; 95% CI: 1.33-2.44), but not recreation. CONCLUSION: The findings suggest that neighborhoods with pedestrian facilities that are attractive and comfortable and where there are local destinations (such as shops and public transport) are associated with walking near home.

Adult↗

PubMed2004

Genetic parameters for six measures of length of productive life and three measures of lifetime production by 6 yr after first calving for Hereford cows.

Genetic parameters for length of productive life given the opportunity (LPL/O), measured as days between first calving and disposal conditioned on one of six opportunity groups, L1 through L6 (e.g., L2 is length of productive life in days given the opportunity to live 2 yr after first calving), and lifetime production (LP), measured as the number of calves born (NB), number of calves weaned (NW), and cumulative weaning weight (CW) by 6 yr after first calving, were estimated using records of 1,886 Hereford cows from a selection experiment with three selected lines and a control line. Weaning weights were adjusted to 200 d of age and for sex and age of dam. Estimates of heritability and genetic and environmental correlations were obtained by restricted maximum likelihood with bivariate animal models, with year of birth of cow as a fixed effect and direct genetic and residual as random effects. Genetic trends were estimated by regressing means of estimated breeding values by year of birth and line on birth year. Estimates of heritability (SE) for LPL/O ranged from 0.05 (0.01) to 0.15 (0.03). Estimates of genetic correlations (SE) among LPL/O ranged from 0.74 (0.14) to 1.00 (0.00), and estimates of environmental correlations ranged from 0.67 (0.05) to 0.98 (0.01). Estimates of heritability (SE) for NB, NW, and CW were 0.17 (0.05), 0.21 (0.06), and 0.18 (0.01). Estimates of genetic correlations (SE) among NB, NW, and CW ranged from 0.96 (0.02) to 0.99 (0.01). Estimates of environmental correlations (SE) ranged from 0.93 (0.01) to 0.99 (0.01). Estimates of genetic correlations for L6 with NB, NW, and CW were near 1.00 (0.09). Estimates of environmental correlations (SE) ranged from 0.57 (0.03) to 0.60 (0.03). Estimates of genetic change per year (SE) for L6 were low for all lines and ranged from -3.53 (2.09) to 4.63 (2.11) d/yr. Genetic trends for NB and NW were negligible for all lines. Genetic trends for CW were low and ranged from -2.81 (1.67) to 3.29 (1.76) kg/yr. Differences in genetic trends between selected lines and control were not significant (P > 0.05). Estimates of environmental trends (SE) over all lines were -104.00 (25.48) d/yr, -0.26 (0.02) calves/yr, -0.25 (0.02) calves/yr, and -55.10 (15.63) kg/yr, for L6, NB, NW, and CW, respectively. Selection for LPLIO or LP could be successful in a breeding program, but may be relatively slow due to the low magnitude of heritability and extended generation interval.

Animals↗

PubMed2004

Number of calves born, number of calves weaned, and cumulative weaning weight as measures of lifetime production for Hereford cows.

Genetic parameters for lifetime production for cows with the opportunity to produce from 2 through 7 yr of age, as measured by the number of calves born (NB2, ..., NB7), the number of calves weaned (NW2, ..., NW7), and cumulative weaning weight (CW2, ..., CW7), were estimated using data from 3,064 Hereford cows from a selection experiment with a control line (CTL) and three lines selected for weaning weight (WWL), yearling weight (YWL), and an index of yearling weight and muscle score (IXL). Weaning weights were adjusted to 200 d of age and for sex and age of dam. Estimates of heritability and genetic and environmental correlations were obtained by restricted maximum likelihood with bivariate animal models, with year of birth of the cow as a fixed effect and direct genetic and residual as random effects. Genetic trends were estimated by regressing means of estimated breeding values by year of birth and line on birth year. Estimates of heritability (SE) for opportunity groups of 2 to 7 yr of age ranged from 0.08 (0.03) to 0.16 (0.05) for NB; from 0.05 (0.02) to 0.16 (0.05) for NW; and from 0.06 (0.02) to 0.16 (0.05) for CW. Estimates of genetic correlations (SE) among NB traits ranged from 0.60 (0.14) to 1.00 (0.00), and estimates of environmental correlations (SE) ranged from 0.67 (0.02) to 0.99 (0.00). For NW, estimates of genetic and environmental correlations ranged from 0.98 (0.11) to 1.00 (0.00) and from 0.65 (0.02) to 0.99 (0.00), respectively. Estimates of genetic correlations (SE) among CW traits ranged from 0.94 (0.08) to 1.00 (0.00). Estimates of environmental correlations (SE) ranged from 0.66 (0.02) to 0.99 (0.00). Estimates of genetic correlations for NB2 with all definitions of NW ranged from 0.47 (0.18) to 0.71 (0.12), and with all definitions of CW ranged from 0.55 (0.16) to 0.80 (0.11). Estimates of genetic correlations between NW2 and all definitions for CW ranged from 0.95 (0.02) to 0.99 (0.06). Estimates of annual genetic (SE) change were negligible for NB2, NB6, NW2, and NW6 for all lines. Estimates of annual genetic (SE) change for CW2 were 0.85 (0.11), 0.79 (0.14), 0.51 (0.10), and 0.52 (0.18) kg/yr, and for CW6 were 5.01 (1.25), 2.64 (1.75), 3.67 (1.16), and 3.33 (2.37) kg/yr for WWL, YWL, IXL, and CTL, respectively. Selection for lifetime production as measured by NB, NW, or CW could be effective but would be relatively slow due to low estimates of heritability and to increased generation intervals.

Animals↗

PubMed2003

Accuracy of marker-assisted selection with auxiliary traits.

Genetic information on molecular markers is increasingly being used in plant and animal improvement programmes particularly as indirect means to improve a metric trait by selection either on an individual basis or on the basis of an index incorporating such information. This paper examines the utility of an index of selection that not only combines phenotypic and molecular information on the trait under improvement but also combines similar information on one or more auxiliary traits. The accuracy of such a selection procedure has been theoretically studied for sufficiently large populations so that the effects of detected quantitative trait loci can be perfectly estimated. The theory is illustrated numerically by considering one auxiliary trait. It is shown that the use of an auxiliary trait improves the selection accuracy; and, hence, the relative efficiency of index selection compared to individual selection which is based on the same intensity of selection. This is particularly so for higher magnitudes of residual genetic correlation and environmental correlation having opposite signs, lower values of the proportion of genetic variation in the main trait associated with the markers, negligible proportion of genetic variation in the auxiliary trait associated with the markers, and lower values of the heritability of the main trait but higher values of the heritability of the auxiliary trait.

Animals↗

PubMed1999

"Quasi-REML" correlation estimates between production and health traits in the presence of selection and confounding: a simulation study.

Performance of the "quasi-REML" method for estimating correlations between a continuous trait and a categorical trait, and between two categorical traits, was studied with Monte Carlo simulations. Three continuous, correlated traits were simulated for identical populations and three scenarios with either no selection, selection for one moderately heritable trait (Trait 1, h2 = .25), and selection for the same trait plus confounding between sires and management groups. The "true" environmental correlations between Traits 2 (h2 = .10) and 3 (h2 = .05) were always of the same absolute size (.20), but further data scenarios were generated by setting the sign of environmental correlation to either positive or negative. Observations for Traits 2 and 3 were then reassigned to binomial categories to simulate health or reproductive traits with incidences of 15 and 5%, respectively. Genetic correlations (r(g12), r(g13), and r(g23) and environmental correlations (r(e12), r(e13), and r(e23)) were estimated for the underlying continuous scale (REML) and the visible categorical scales ("quasi-REML") with linear multiple-trait sire and animal models. Contrary to theory, practically all "quasi-REML" genetic correlations were underestimated to some extent with the sire and animal models. Selection inflated this negative bias for sire model estimates, and the sign of r(e23) noticeably affected r(g23) estimates for the animal model, with greater bias and SD for estimates when the "true" r(e23) was positive. Transformed "quasi-REML" environmental correlations between a continuous and a categorical trait were estimated with good efficiency and little bias, and corresponding correlations between two categorical traits were systematically overestimated. Confounding between sires and contemporary groups negatively affected all correlation estimates on the underlying and the visible scales, especially for sire model "quasi-REML" estimates of genetic correlation. Selection, data structure, and the (co)variance structure influences how well correlations involving categorical traits are estimated with "quasi-REML" methods.

Animal Husbandry↗

PubMed2001

Genetic regulation of plasma levels of vitamin K-dependent proteins involved in hematostatis: results from the GAIT Project. Genetic Analysis of Idiopathic Thrombophilia.

Vitamin K-dependent proteins play a critical role in hemostasis. We have analysed the genetic and environmental correlations between measures of several vitamin K-dependent proteins in 21 Spanish extended families, including 397 individuals. Plasma functional levels of factors II, VII, IX, X, protein C and functional protein S were assayed in an automated coagulometer. Antigenic levels of total and free protein S were measured using an ELISA method. A maximum likelihood-based covariance decomposition analysis was used to assess the heritability of each trait and the genetic and environmental correlations between all possible pairs. All of the plasma levels had a significant genetic component (heritability) ranging from 22% to 52% of the phenotypic variance. Among the 28 possible pairs of genetic correlations, 18 were significant at a level of p < 0.05 and six exhibited a p-value between 0.05 and 0.10. Positive environmental correlation was observed for 25 of the pairs (p < 0.05). We conclude that genetic effects account for a large proportion of the observed phenotypic variation in vitamin K-dependent proteins. Some of the genes appear to pleiotropically influence all of these traits, since most pairs of phenotypes exhibit significant genetic correlation. However, since these phenotypes show a high degree of environmental correlation, it is also likely that the same environmental factors influence them co-jointly.

Adolescent↗

PubMed2004

Genetic analysis of the Israeli Holstein dairy cattle population for production and nonproduction traits with a multitrait animal model.

Milk, fat, and protein production, somatic cell score (SCS), and female fertility in the Israeli Holstein dairy cattle population were analyzed using a multitrait animal model (AM) with parities 1 through 5 as separate traits. Female fertility was measured as the inverse of the number of inseminations to conception in percent. Variance components were estimated using both the repeatability AM and multitrait AM. The multitrait heritabilities for individual parities were greater than the heritabilities from the repeatability AM, and heritabilities decreased with an increase in parity number. Heritabilities were higher for production traits, lower for SCS, and lowest for female fertility. The genetic correlations were higher than the environmental correlations. Genetic correlations between parities decreased with an increase in the difference in parity number, but all were greater than 0.5. The environmental correlations were higher for production traits, lower for SCS, and close to zero for female fertility. In the analysis of the complete milk recorded population, genetic trends from the repeatability and multitrait models were very similar. The genetic trend for SCS was economically unfavorable until 1993, and favorable since then. The genetic trend for female fertility was close to zero, but the annual environmental trend was -0.2%. The multitrait lactation model is an attractive compromise between repeatability lactation models, which do not account for maturing trends across parities, and test-day models, which are much more demanding computationally.

Animals↗

PubMed2005

Extinction risk of a meta-population: aggregation approach.

Aggregation of variables of a complex mathematical model with realistic structure gives a simplified model which is more suitable than the original one when the amount of data for parameter estimation is limited. Here we explore use of a formula derived for a single unstructured population (canonical model) in predicting the extinction time for a population living in multiple habitats. In particular we focus multiple populations each following logistic growth with demographic and environmental stochasticities, and examine how the mean extinction time depends on the migration and environmental correlation. When migration rate and/or environmental correlation are very large or very small, we may express the mean extinction time exactly using the formula with properly modified parameters. When parameters are of intermediate magnitude, we generate a Monte Carlo time series of the population size for the realistic structured model, estimate the "effective parameters" by fitting the time series to the canonical model, and then calculate the mean extinction time using the formula for a single population. The mean extinction time predicted by the formula was close to those obtained from direct computer simulation of structured models. We conclude that the formula for an unstructured single-population model has good approximation capability and can be applicable in estimating the extinction risk of the structured meta-population model for a limited data set.

Animals↗

PubMed1982

The manifestation of genotypes responsible for blood pressure and blood sugar level.

It has been known for a long time that hypertension and diabetes mellitus are often complicated by each other. The aim of this paper was to disclose possible causes of such complications by investigating 1) whether or not hypertension and diabetes mellitus are entirely two independent diseases, 2) whether or not they occur together only by chance, 3) whether or not there are some causal factors which are shared by these two diseases and 4) whether or not these two diseases occur together with some probability. The genetic analyses of these two diseases were carried out on the basis of the genetic analyses on blood pressures (BP) and blood sugar levels (BS) in the present studies. It was proved that the genotypic correlation coefficients of BP and BS ranged from 0.075 to 0.573 with a mean value of 0.337 and their environmental correlation coefficients were from -0.029 to -0.337 with a mean value of -0.164. These results suggest that 1) the respective polygenic systems responsible for BP (hypertension) and BS (diabetes mellitus) have multiple effects and 2) the environmental factors responsible for BP and BS have inverse effects. The negative values of the environmental correlation coefficients between BP and BS indicate that the environmental factors which lower BP may elevate BS, and vice versa. An induction of an abnormal glucose tolerance as one of the side effects of thiazides, the most widely used anti-hypertensive diuretics, coincides with the inverse environmental correlation between BP and BS. This finding may be of great importance in the field of clinical genetics.

Adult↗

PubMed2002

Effect of duration of performance test on variance component estimates for lamb growth rate.

The objective was to determine the effect of periods of adjustment and duration of performance test on estimating genetic variance parameters for ADG. Variance components were estimated from ADG data collected from 1978 to 1984 on a total of 1,047 Targhee ewe and ram lambs at the U.S. Sheep Experiment Station (Dubois, ID). Across all years, lambs averaged 84 +/- 9 d of age and 25 +/- 5.4 kg of weight when placed on test. Lambs were provided ad libitum access to a commercial pellet of barley grain and ground alfalfa for 14 wk. Every 2 wk, ADG was recorded. Overall mean ADG for the entire 14-wk period across all years was 249.3 +/- 56.5 g. Variance components were estimated from a single-trait animal model using REML for cumulative combinations of time on feed in 2-wk intervals from 4 to 14 wk and varying the adjustment period from 2 to 6 wk. The model included fixed effects for year (1978 to 1984), sex of lamb (ewe or ram), and genetic line (selected or control), and two covariates (age and weight at beginning of performance test). As the duration of the performance test increased, phenotypic variances for ADG decreased: 54 and 13 g2 at 4 and 14 wk on test, respectively. Also, estimates of direct heritability increased with extended duration on test: 0.20 +/- 0.06 and 0.35 +/- 0.07 at 4 and 14 wk on test, respectively. Heritability estimates increased little after 8 wk on feed (0.33, 0.33,0.38, and 0.35 for 8, 10, 12, and 14 wk, respectively). Genetic and environmental correlations among durations of the performance test were estimated from two-trait models. All genetic correlations among durations of performance test were greater than 0.88 which suggests that all measures of ADG were genetically similar. However, environmental correlations among duration of performance test ranged from 0.31 to 1.00 with the smaller environmental correlations occurring between 4 to 6 wk with 12 to 14 wk on feed. These results indicate that a period of 8 wk or greater was sufficient to observe differences among animals for ADG due to direct genetic effects under this environment.

Age Factors↗

PubMed1999

Why do measures of normal and disordered personality correlate? A study of genetic comorbidity.

The genetic and environmental correlations between measures of normal (NEO-FFI) and abnormal personality (Dimensional Assessment of Personality Pathology: DAPP-BQ) were estimated in a sample of 545 volunteer general population twin pairs (269 monozygotic and 276 dizygotic pairs). The largest genetic correlations were observed between the 18 DAPP-BQ dimensions and NEO-FFI neuroticism (range = .05 to .81; median = .48), extraversion (range = -.65 to .33; median = -.28), agreeableness (range = -.65 to .00; median = -.38), and conscientiousness (range = -.76 to .52; median = -.31). The smallest genetic correlations were found between the DAPP-BQ dimensions and NEO-FFI openness (range = -.17 to .20; median = -.04). The environmental correlations are lower in magnitude but show the same pattern of correlations between DAPP-BQ and NEO-FFI scales. These results indicate that these two scales share a common broad-based genetic architecture, whereas the environmental influences show greater scale specificity.

Adolescent↗

PubMed2002

Estimating two-stage models for genetic influences on alcohol, tobacco or drug use initiation and dependence vulnerability in twin and family data.

Genetic research on risk of alcohol, tobacco or drug dependence must make allowance for the partial overlap of risk-factors for initiation of use, and risk-factors for dependence or other outcomes in users. Except in the extreme cases where genetic and environmental risk-factors for initiation and dependence overlap completely or are uncorrelated, there is no consensus about how best to estimate the magnitude of genetic or environmental correlations between Initiation and Dependence in twin and family data. We explore by computer simulation the biases to estimates of genetic and environmental parameters caused by model misspecification when Initiation can only be defined as a binary variable. For plausible simulated parameter values, the two-stage genetic models that we consider yield estimates of genetic and environmental variances for Dependence that, although biased, are not very discrepant from the true values. However, estimates of genetic (or environmental) correlations between Initiation and Dependence may be seriously biased, and may differ markedly under different two-stage models. Such estimates may have little credibility unless external data favor selection of one particular model. These problems can be avoided if Initiation can be assessed as a multiple-category variable (e.g. never versus early-onset versus later onset user), with at least two categories measurable in users at risk for dependence. Under these conditions, under certain distributional assumptions, recovery of simulated genetic and environmental correlations becomes possible. Illustrative application of the model to Australian twin data on smoking confirmed substantial heritability of smoking persistence (42%) with minimal overlap with genetic influences on initiation.

Australia↗

PubMed2003

Lack of correlation between environmental or biological indicators of benzene exposure at parts per billion levels and micronuclei induction.

Despite growing concern for possible carcinogenic effects associated with environmental benzene exposure in the general population, few studies exist at parts per billion (ppb) levels. We investigated the existence of a relationship between airborne/biological measurements of benzene exposure (i.e., personal/area sampling and unmodified urinary benzene/trans,trans-muconic acid; t,t-MA) and micronuclei induction (cytochalasin B technique) among exposed chemical laboratory workers (n=47) and traffic wardens (n=15). Although urinary t,t-MA (106.9+/-123.17 microg/L(urine)) correlated (R(2)=0.37) with urinary benzene (0.66+/-0.99 microg/L(urine)), neither biological measurement correlated with environmental benzene exposure (14.04+/-9.71 microg/m(3); 4.39+/-3.03ppb), suggesting that, at ppb level (1ppb=3.2 microg/m(3)), airborne benzene constitutes a fraction of the total intake. Traffic wardens and laboratory workers had comparable numbers of micronuclei (4.70+/-2.63 versus 5.76+/-3.11; n.s.), similar to levels recorded in the general population. With univariate/multivariate analysis, no association was found between micronuclei induction and air/urinary benzene exposure variables. Notably, among the personal characteristics examined (including age, gender, smoking, drinking, etc.), high body mass index correlated with micronuclei induction while, among females, use of hormonal medication was associated with less micronuclei. Thus the present study provides no evidence that ppb levels of environmental benzene exposure appreciably affect micronuclei incidence (against the background of other relevant factors). However, this should not be taken as an argument against efforts aiming to reduce environmental benzene pollution.

Adult↗

PubMed2003

Correlates of physical activity in urban Midwestern African-American women.

BACKGROUND: African-American women are at higher risk than white women of cardiovascular disease and stroke. In addition, fewer African-American women reap the cardiovascular benefits of exercise, because of low physical activity. The study goals were to identify personal, social environmental, and physical environmental correlates of physical activity of urban-dwelling, Midwestern, African-American women and to obtain their recommendations for increasing exercise in their communities. METHODS: A face-to-face interview (Women and Physical Activity Survey) covering personal, social environmental, and physical environmental correlates of physical activity was administered to 399 volunteer African-American women aged 20 to 50 years, living in Chicago. Physical activity was measured with questions on lifestyle and planned leisure-time activity (exercise) from the Behavioral Risk Factor Surveillance System. RESULTS: The women were from a wide socioeconomic spectrum of education and income. Forty-two percent of the women met current recommendations for moderate or vigorous physical activity; 48% were insufficiently active; and 9% were inactive. The following groups of women were more likely to be physically active: women with at least a high school education; women with perceived good health; women who knew people who exercise; and women who viewed the neighborhood as safe. These findings were statistically significant. CONCLUSIONS: Interventions that target urban African-American women must address the safety of the physical environment and personal and social environmental correlates of physical activity, and they should focus especially on inactive women who have less than a high school education or perceive themselves to be in poor health.

Adult↗

PubMed2004

Genetic and environmental contributions to carotid intima-media thickness and obesity phenotypes in the Northern Manhattan Family Study.

BACKGROUND AND PURPOSE: Both carotid intima-media thickness (IMT) and obesity are independent determinants of stroke and cardiovascular disease. The prevalence of obesity is higher in Hispanics. The genetic basis of IMT and obesity has not been well-characterized in Caribbean Hispanics. The purpose of this study was to examine the genetic and environmental contributions to IMT and obesity in this population. METHODS: The data included 440 subjects from 77 Caribbean Hispanic families. Mean IMT and maximum IMT were measured in the internal carotid artery, common carotid artery, and carotid bifurcation. The total IMT was calculated as the mean value of IMT at all segments. Obesity phenotypes included body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), and skin-fold thickness. Variance component methods were used to estimate age-adjusted and sex-adjusted heritability. Bivariate analyses were conducted to test for genetic and environmental correlations between IMT and obesity. RESULTS: Heritabilities for IMT ranged from 9% to 40%, with the highest for total maximum IMT and lowest for internal carotid artery maximum IMT. Heritabilities for BMI, waist circumference, WHR, and skin-fold thickness were 44%, 47%, 5%, and 36%, respectively. There were significant genetic, but not environmental, correlations between IMT and BMI, waist circumference, and skin-fold thickness. There were no genetic or environmental correlations between IMT and WHR. CONCLUSIONS: We found a substantial genetic contribution to IMT, BMI, waist circumference, and skin-fold thickness. Obesity and IMT may share common genetic factors. Future gene mapping studies are warranted to identify genes predisposing to IMT and obesity in this population.

Adult↗

PubMed2004

Correlation of environmental factors with asthma and rhinitis symptoms in Tulsa, OK.

BACKGROUND: Airborne allergens, pollutants, and climatic changes are known to influence the symptoms of asthma patients. OBJECTIVE: To correlate airborne fungal spore and pollen concentrations, meteorological data, and airborne pollutants with asthma and rhinitis symptoms to develop predictive models for asthma severity. METHODS: Patients from the Tulsa community participated in this study from September 1 to October 31, 2000, by filling out daily symptom diaries and measuring morning and evening peak expiratory flow rates. Air samples were collected using a volumetric spore trap. Meteorological variables and maximum and average pollutants were also included in the analysis. Linear regression analyses were performed for all environmental variables and symptom scores. Forward stepwise multiple regression analyses were performed to determine sets of variables that could be used to predict the conditions of increased symptom severity. RESULTS: Twenty-four patients participated in this study. The predominant spore types included Cladosporium, ascospores, and basidiospores. The predominant pollen type was Ambrosia. September was unusually hot and dry in Tulsa, but 161 mm of precipitation fell in October, primarily during the last 11 days. Two periods of peak symptoms occurred during the study, the first during the peak week of Ambrosia and the second after a 22 degrees C drop in temperature over 6 days. Numerous environmental variables showed significant correlations with symptom scores; however, there was no single predictive model for all symptoms. CONCLUSIONS: Ambrosia pollen and other environmental variables, including ozone levels, were significantly correlated with asthma and rhinitis symptoms.

Adolescent↗

PubMed1981

Genetic and environmental influences on milk and milk component production.

Estimates of genetic parameters and environmental correlations were from deviations from modified contemporary average of standardized records of first lactations of Holsteins in Pennsylvania. Records were extended to 305 days and adjusted for month of calving prior to calculation of deviations. Heritabilities from intrasire correlations among paternal sisters were .23, .26, .22, .71, and .64 for yields of milk, fat, and protein, and percentages of fat and protein. Genetic correlations were positive and generally high between yields and between percentages. Correlations of milk yield with percentages were strongly negative. Environmental correlations among paternal sisters in the same herd were .08, .11, .10, -.04, and -.03 for yields of milk, fat, and protein, and percentages of fat and protein. These statistics will be useful to plan optimum selection programs and to improve sire evaluation procedures, particularly for protein content and yield.

Animals↗