Expressions of life meaning among college students.

This study examined the views of 132 undergraduate students (35 men, 97 women) regarding what they considered to be contributing factors to a worthwhile or meaningful life. They rated, on a 5-point Likert scale, their agreement with each of 40 statements. Cluster analysis yielded three clusters which best described the data. One cluster comprised a religious group, and the other two clusters were nonreligious, with one having characteristics of both the religious and nonreligious cluster.

Application of hidden Markov models on residuals: an example using Canadian traffic accident data.

Laverty, Kelly, Rotton, and Flynn conducted a regression analysis in 1992 on 9 years of automobile accidents in Saskatchewan (a total of 200,545 accidents) to find a small linear trend, season effects, holiday, and day of the week effects. The application of a hidden Markov model to the residuals of this analysis uncovered two states which are likely to be related to the weather. These states can be described as low volatility' and 'high volatility'. The 'low volatility' state involves low variability compared to the 'high volatility' state (occurring during the colder months) during which the largest numbers of accidents occur. It is suggested that hidden Markov models are a useful method for uncovering hidden, underlying states in social science and health-related data.

Examination of residuals to Vancouver crisis call data by using hidden Markov models.

Three years of daily crisis calls (N=2,513,478) were examined in a regression analysis with terms for effects for weekday, end and beginning of the month, holiday, seasonal trend, and long-term linear trend. This was followed by an analysis of residuals using hidden Markov models, with three states best fitting the residuals. These states may reflect economic or environmental variables which researchers should clarify in further work.

Cyclical calendar and lunar patterns in automobile property accidents and injury accidents.

Nine years of traffic accidents involving damage to property (n = 246,926 accidents) and involving nonfatal injury (n = 50,492) in Saskatchewan were examined by regression and spectral analyses. Both calendar and seasonal periodicities were found in both sets of data. After data were adjusted for calendar effects, no relationship was found with the total or half synodic and anomalistic lunar cycles or between the waxing and waning synodic cycle. No sudden change on the day of the full moon or surrounding days was found.

Analysis of polymorphic variation in drug metabolism: I. Kernal density estimation.

Kernel density estimation was examined as an objective, nonparametric approach to the detection of polymorphic variation in distributions containing multiple complex data sets. Power curves were constructed for the kernel density estimate based on its ability to detect worked bimodality in stimulated distributions as a function of the distribution size, the fraction contained within a particular subdistribution, and the location of the mean of that subdistribution with respect to the mean of the overall distribution. Comparisons were then made between kernel density estimation and the Kolmogorov-Smirnov test of maximal differences. Results showed that kernel density estimation performed as well or better than the Kolmogorov-Smirnov test and offered a number of advantages, including identification of the frequency and placement of individual modes and antimodes. The Kolmogorov-Smirnov test, on the other hand, examined normality of a distribution rather than modality or inherent polymorphism, and the outcome was highly dependent on the subdistribution location and total distribution size. We conclude that kernel density estimation is an excellent method for analysis of polymorphic variation in drug metabolism.

Geophysical variables and behavior: LXVIII. Distal and lunar variables and traffic accidents in Saskatchewan 1984-1989.

The daily total number of traffic accidents and traffic accident severity for the years 1984 to 1989 in Saskatchewan were analyzed to estimate relationships with day of the week, season of the year, and various lunar variables (lunar phase, distance of the moon from the earth, and moon-sun tidal index). A regression model with both a linear term and a trigonometric term was fitted to the data. No relationship between lunar cycles and total accidents or severity of accident was found. A larger number of total accidents was found during the winter months and weekends; however, more severe accidents tended to occur during the summer months. A slight linear trend was uncovered for total accidents over the time period under consideration.

Multivariate statistical analysis of stride-timing measurements of nonfatigued racing Thoroughbreds.

Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0.644). The 2 components of stride, the suspension and stride-stance phases, lasted on average, 0.114 s and 0.291 s or 28.07% and 72.01% of the stride duration, respectively. The correlation between stride-stance and suspension phases was low (r = 0.1767). Timing of the forelimbs, rather than overall stance-phase duration, may influence the duration of the suspension phase because four of seven variables selected in a stepwise-regression analysis were exclusively from the forelimbs. The stance-phase duration, and therefore swing-phase duration, of all four limbs differed significantly (P less than 0.05). The left forelimb (LF) and right hind limb (RH) had significantly shorter stance and single-support phases. Forelimb and hind limb pairs differed in their timing and coordination. There were differences in advanced placement and overlap of the hind limbs, compared with that in the forelimbs. Significant (P less than 0.05) differences were found between three limb overlap measurements. The overlap between the forelimbs was shortest and that between the hind limbs was the longest in duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Clonidine fails to reduce pressor responsiveness of conscious spontaneously hypertensive rats to vasopressin.

Pressor responses and heart rate responses to intravenous injections (3.5-50.0 pmol/kg) of arginine vasopressin (AVP) were recorded in saline- and clonidine-treated spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Clonidine (20 micrograms/kg, i.v.) caused a marked fall of arterial pressure in SHR but not in WKY rats so that, 20 min after the injection of the alpha 2-adrenoceptor agonist, arterial pressure was similar in the two strains of rats. The curve expressing the relationship between the dose of AVP and the increase of arterial pressure for saline-treated SHR was positioned to the left of that for saline-treated WKY rats. This enhanced pressor responsiveness of SHR to AVP may have been related to impaired reflex activity since heart rate fell much less in SHR than in WKY rats for a given elevation in pressure. Pressure responses to AVP were augmented by clonidine in both SHR and WKY rats so that, similar to saline-treated rats, pressor responsiveness to the peptide was still greater in SHR. Heart rate responses to AVP were not altered significantly by clonidine. The results indicate that clonidine fails to enhance reflex activity and reduce pressor responsiveness of SHR to AVP. The increased pressor responsiveness of both SHR and WKY rats to AVP following clonidine was an unexpected finding and may be related to a peripheral interaction between alpha-adrenergic agonists and AVP.

Reduced binding of basic somatomedin by mouse placental membranes following maternal alcohol administration.

The effects of 3 days of maternal ethanol administration on the placenta and on basic somatomedin (B-SM) were investigated in the mouse. Following administration of aqueous ethanol by gavage on days 13, 14 and 15 of gestation, there was no treatment-related difference in embyonic growth or placental weight as seen on day 15. There was a significant reduction in the specific binding of [125I]B-SM by day 15 placental membranes, but no difference in serum B-SM concentrations or in the frequency or severity of degenerative changes in the placenta. We have shown that changing levels of serum B-SM over the normal course of pregnancy correspond closely to patterns of cellular proliferation and aging in the placenta. It is possible that impairment in the binding activity of B-SM receptors contributes to the premature aging observed in term placentas exposed to alcohol during pregnancy in the rodent.

Effects of citric acid treatment on autogenous free graft coverage of localized recession.

Citric acid root conditioning prior to free gingival autograft (FGA) coverage of denuded roots may increase the likelihood of reattachment, but controlled studies to determine the value of the procedure have not been done on human subjects. This investigation was done to compare the effects of FGA root coverage with and without citric acid pretreatment. Nineteen patients with 30 affected teeth participated in the study. Fifteen teeth received FGAs without citric acid pretreatment and 15 teeth received FGAs with citric acid pretreatment. Measurements of gingival recession and sulcus depth were made preoperatively and 30, 60 and 90 days following the surgical procedure. Free gingival autografts with and without citric acid pretreatment each significantly reduced the amount of exposed root, but no differences between groups were found. Except for the 90-day single tooth control group, mean sulcus depths were significantly decreased at 30, 60 and 90 days, but there were no differences noted between single tooth citric acid and control groups or multiple tooth citric acid and control groups. Citric acid treatment of affected roots prior to FGA coverage does not appear to be justifiable.

Does antacid prophylaxis prevent upper gastrointestinal bleeding in critically ill patients?

Sixty-five surgical ICU patients at high risk of developing acute erosive gastritis and bleeding received prophylactic antacid treatment to maintain a gastric pH of at least 5.0. A similar control group of 61 patients received no specific prophylaxis. All patients in both groups developed microscopic bleeding; however, microscopic bleeding did not influence outcome. In the control group, eight (13.1%) patients developed moderate visible bleeding, as compared to seven (10.8%) patients in the antacid group, an insignificant difference. A single patient in the control group developed severe GI bleeding due to acute erosive gastritis. Antacid prophylaxis did not prevent macroscopic bleeding and there was no correlation between the number of risk factors in individual patients and the rate of upper GI bleeding. We conclude that antacid is not required to prevent upper GI bleeding in high-risk critically ill patients.

Effects of citric acid treatment on pedicle flap coverage of localized recession.

Citric acid conditioning of denuded roots prior to laterally positioned pedicle flap (LPPF) coverage may increase the likelihood of reattachment, but no controlled studies to determine the efficacy of the procedure in managing naturally occurring defects in humans have been reported. This investigation compared the effects of LPPF root coverage with and without citric acid (pH1) pretreatment in a group of patients with gingival recession and associated denuded roots. Thirty-six patients participated in the study. Eighteen received LPPFs without citric acid pretreatment and 18 received LPPFs with citric acid pretreatment. Gingival recession and sulcus depth were measured preoperatively and 30, 60 and 90 days after the surgical procedure. LPPFs both with and without citric acid pretreatment reduced significantly the amount of exposed root, but no differences between groups were found. For sulcus depth, the 90-day value for the citric acid group was significantly increased over the preoperative level, but no other changes were noted. There appears to be no clinical justification for using citric acid conditioning as an adjunct to LPPF coverage of denuded roots.

Chronic low-dose levodopa therapy in Parkinson's disease: an argument for delaying levodopa therapy.

Levodopa is the most useful drug for treatment of Parkinson's disease today. But after continued use for several years, the effectiveness declines, and the undesirable side effects become more frequent, leading to unsatisfactory control. Once the treatment failure emerges, further management is difficult and often unsuccessful. One alternative for preventing side effects and treatment failure is to use a low dose. We are reporting our 12-year experience on uninterrupted treatment with levodopa, 3 grams (approximate) daily. The improvement was comparable with the best reports on higher dosage, and the side effects were significantly less frequent. The frequency of dyskinesia and on-off phenomena showed a strong correlation with duration of treatment. Psychiatric side effects were more common on treatment, but frequency of dementia did not correlate with duration of therapy. Improvement reached a peak after 6 months and remained statistically significant for 3.5 years. By the end of 5 years, the disability profile in the group was similar to that prior to levodopa treatment. So far, there is no satisfactory method for preventing treatment failure. From our observations, low dosage of levodopa is a desirable alternative, but not the answer to therapeutic failure. We recommend that levodopa use be delayed until the patient has a functional and/or psychological handicap that cannot be satisfactorily controlled with less potent antiparkinsonian agents.

Reductions in the plating efficiency of the fetal neural precursor cells following maternal alcohol consumption.

Maternal alcohol abuse has been associated with reduced neural cell number and abnormal cell differentiation and organization in many regions of the developing mammalian brain. Experiments were conducted to determine whether changes in the neural precursor cells could be detected in primary culture following maternal alcohol consumption during the early proliferative period of the fetal brain growth spurt. Alcohol was administered to pregnant mice in the drinking water from days 11 to 19 of gestation. There was no alcohol-related increase in the incidence of fetal mortality or malformation, but fetal body and brain weights were reduced. When disaggregated cells from the day 19 fetal neopallium were grown in culture, there was a reduction in the number of astroglial colonies yielded in 42% of alcohol-exposed brains. This effect was expressed as a reduction in the absolute plating efficiency (APE) of the neural precursor cells. The APE was reduced as much as 80% in severely affected brains. There was no alcoholrelated difference in the in vitro morphogenesis of the astroglial colonies. Observations of the proliferative neural cells in situ suggest that there is an impaired recruitment of all neural cell types, but that the reduced APE reflects primarily a proportionate increase in the number of immature neurons among the cells obtained from the fetal neopallium. It appears that a prolongation of mitosis may be resulting in a general developmental delay in the fetal neocortex.

A mathematical model of speedskating performance improvement for goal setting and program evaluation.

An analysis of world class performance improvement over chronological time was used to develop mathematical curves of performance for each speedskating event. The equations were calculated using an unconstrained non-linear least squares iterative curve-fitting technique. A non-linear model was selected to satisfy the principle of diminishing returns, that is, it is more difficult to achieve a unit of performance improvement as performance approaches the theoretical limits of man. Minimum criteria of acceptance for each curve were: 1) the coefficient of determination must be 0.90; 2) the year 2000 predicted value must be less than the current world record; and 3) the curve must be progressive, i.e. satisfy the principle of diminishing returns. Satisfactory curves were calculated for seven of the eight male and female events studied. A four year Olympic cycle was noted and a definite change in performance trend was identified as occurring in the mid 1960's. The calculated mathematical curves can be used in three applications: 1) setting objective individual goals and evaluating these goals; 2) evaluating and comparing training programs on successive years; and 3) evaluating total programs.