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PubMed1996

Capodanno Senza Danno: the effects of an intervention program on fireworks injuries in Naples.

To study the effects of a comprehensive, multifaceted intervention program to reduce fireworks-related injuries during the Italian New Year's holiday season, active surveillance was conducted in the 18 public emergency rooms of Naples, Italy, before and after implementation of the program. Preintervention data collected between December 24, 1992, and January 6, 1993, were compared with data collected during the same period in 1993-1994. The number of injuries decreased by 48% from 353 to 183, with the greatest declines seen among 10- to 12-year-olds. The broad-based intervention implemented during the 1993-1994 holiday season appears to have substantially reduced the number of injuries.

Adult↗
PubMed1999

Lot quality assurance sampling (LQAS) for monitoring a leprosy elimination program.

In a statistical sense, prevalences of leprosy in different geographical areas can be called very low or rare. Conventional survey methods to monitor leprosy control programs, therefore, need large sample sizes, are expensive, and are time-consuming. Further, with the lowering of prevalence to the near-desired target level, 1 case per 10,000 population at national or subnational levels, the program administrator's concern will be shifted to smaller areas, e.g., districts, for assessment and, if needed, for necessary interventions. In this paper, Lot Quality Assurance Sampling (LQAS), a quality control tool in industry, is proposed to identify districts/regions having a prevalence of leprosy at or above a certain target level, e.g., 1 in 10,000. This technique can also be considered for identifying districts/regions at or below the target level of 1 per 10,000, i.e., areas where the elimination level is attained. For simulating various situations and strategies, a hypothetical computerized population of 10 million persons was created. This population mimics the actual population in terms of the empirical information on rural/urban distributions and the distribution of households by size for the state of Tamil Nadu, India. Various levels with respect to leprosy prevalence are created using this population. The distribution of the number of cases in the population was expected to follow the Poisson process, and this was also confirmed by examination. Sample sizes and corresponding critical values were computed using Poisson approximation. Initially, villages/towns are selected from the population and from each selected village/town households are selected using systematic sampling. Households instead of individuals are used as sampling units. This sampling procedure was simulated 1000 times in the computer from the base population. The results in four different prevalence situations meet the required limits of Type I error of 5% and 90% Power. It is concluded that after validation under field conditions, this method can be considered for a rapid assessment of the leprosy situation.

Computer Simulation↗
PubMed2005

New evidence of the effects of agro-ecologic change on malaria transmission.

Although maize pollen is known to provide nutrition for larval anopheline mosquitoes, the epidemiologic relationship between maize agriculture and malaria transmission has never been defined. To determine whether recent changes in malaria transmission in Ethiopia might be linked to the spread of maize as a commercial crop, we compared malaria transmission and maize cultivation intensity in 21 villages in the Bure District of northwestern Ethiopia where maize cultivation has recently expanded. The cumulative incidence in high maize cultivation areas was 9.5 times higher than in areas with less maize. A chi-square goodness-of-fit test results showed that malaria cases were not distributed evenly among categories of maize cultivation intensity, (chi2 = 1,578, P < 0.001). A Poisson regression suggested that the intensity of maize cultivation, controlled for differences in elevation between sites, was positively and significantly correlated with malaria incidence. Thus, the intensity of maize cultivation was associated with exacerbated human risk of malaria in Bure.

Agriculture↗
PubMed1992

Observations on the bionomy of Allocreadium isoporum (Looss, 1894) (Trematoda: Allocreadiidae).

From October 1985 until July 1987, the bionomy of the trematode Allocreadium isoporum (Looss, 1894) was studied in the Rokytná River (the Danube basin), Czechoslovakia. While clams of the genera Sphaerium Scopoli and Pisidium Pfeiffer apparently serve as its first intermediate hosts, mayfly larvae Ephemera danica Müll. were found (prevalence 8%, intensity 1-5 metacercariae per mayfly) to be the only second intermediate host of A. isoporum in the locality. The most important definitive host is chub, Leuciscus cephalus (L.), in which the seasonal dynamics of A. isoporum occurrence and maturation was followed. The parasite exhibits here a distinct seasonal cycle of maturation which is shown mainly by quantitative changes in the ratio of young to mature worms containing eggs. The trematodes containing eggs occur almost throughout the year, but mainly in the spring and early summer (maximum in May), and after the oviposition they leave the host. New infections are acquired by chub all the year round. This seasonal periodicity is determined by ecological factors, mainly the temperature regime in the locality. A isoporum infections in chub in this locality are dependent on the body size of host fishes; the highest degree of A. isoporum infection occurs in fishes 20-25 cm long, the prevalence decreasing somewhat in larger fishes; infection is associated with changes in the food composition of chub of different size groups.

Animals↗
PubMed1990

[An analysis of industrial accidents in the working field with a particular emphasis on repeated accidents].

The present study is based on an analysis of routinely submitted reports of occupational accidents experienced by the workers of industrial enterprises under the jurisdiction of Kagoshima Labor Standard Office during a 5-year period 1983 to 1987. Officially notified injuries serious enough to keep employees away from their job for work at least 4 days were utilized in this study. Data was classified so as to give an observed frequency distribution for workers having any specified number of accidents. Also, the accident rate which is an indicator of the risk of accident was compared among different occupations, between age groups and between the sexes. Results obtained are as follows; 1) For the combined total of 6,324 accident cases for 8 types of occupation (Construction, Transportation, Mining & Quarrying, Forestry, Food manufacture, Lumber & Woodcraft, Manufacturing industry and Other business), the number of those who had at least one accident was 6,098, of which 5,837 were injured only once, 208 twice, 21 three times and 2 four times. When occupation type was fixed, however, the number of workers having one, two, three and four times of accidents were 5,895, 182, 19 and 2, respectively. This suggests that some workers are likely to have experienced repeated accidents in more than one type of occupation.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Occupational↗
PubMedDate not supplied

[The use of dicentric distribution in human peripheral blood lymphocytes for the retrospective estimation of the irradiation dosage].

The paper presents the results of retrospective dose estimations in a number of Chernobyl victims by different approaches to the analysis of dicentric distribution in peripheral lymphocytes in blood samples taken a long time after the accident. Retrospective dose estimations are compared with dose estimates in the same individuals made immediately after the accident by dicentric frequencies.

Chi-Square Distribution↗
PubMed1997

Statistical methods for estimating doubling time in in vitro cell growth.

Doubling time has been widely used to represent the growth pattern of cells. A traditional method for finding the doubling time is to apply gray-scaled cells, where the logarithmic transformed scale is used. As an alternative statistical method, the log-linear model was recently proposed, for which actual cell numbers are used instead of the transformed gray-scaled cells. In this paper, I extend the log-linear model and propose the extended log-linear model. This model is designed for extra-Poisson variation, where the log-linear model produces the less appropriate estimate of the doubling time. Moreover, I compare statistical properties of the gray-scaled method, the log-linear model, and the extended log-linear model. For this purpose, I perform a Monte Carlo simulation study with three data-generating models: the additive error model, the multiplicative error model, and the overdispersed Poisson model. From the simulation study, I found that the gray-scaled method highly depends on the normality assumption of the gray-scaled cells; hence, this method is appropriate when the error model is multiplicative with the log-normally distributed errors. However, it is less efficient for other types of error distributions, especially when the error model is additive or the errors follow the Poisson distribution. The estimated standard error for the doubling time is not accurate in this case. The log-linear model was found to be efficient when the errors follow the Poisson distribution or nearly Poisson distribution. The efficiency of the log-linear model was decreased accordingly as the overdispersion increased, compared to the extended log-linear model. When the error model is additive or multiplicative with Gamma-distributed errors, the log-linear model is more efficient than the gray-scaled method. The extended log-linear model performs well overall for all three data-generating models. The loss of efficiency of the extended log-linear model is observed only when the error model is multiplicative with log-normally distributed errors, where the gray-scaled method is appropriate. However, the extended log-linear model is more efficient than log-linear model in this case.

Cell Division↗
PubMed2001

Numerical solution of differential equations using multiquadric radial basis functions networks.

This paper presents mesh-free procedures for solving linear differential equations (ODEs and elliptic PDEs) based on multiquadric (MQ) radial basis function networks (RBFNs). Based on our study of approximation of function and its derivatives using RBFNs that was reported in an earlier paper (Mai-Duy, N. & Tran-Cong, T. (1999). Approximation of function and its derivatives using radial basis function networks. Neural networks, submitted), new RBFN approximation procedures are developed in this paper for solving DEs, which can also be classified into two types: a direct (DRBFN) and an indirect (IRBFN) RBFN procedure. In the present procedures, the width of the RBFs is the only adjustable parameter according to a(i) = betad(i), where d(i) is the distance from the ith centre to the nearest centre. The IRBFN method is more accurate than the DRBFN one and experience so far shows that beta can be chosen in the range 7 < or = beta 10 for the former. Different combinations of RBF centres and collocation points (uniformly and randomly distributed) are tested on both regularly and irregularly shaped domains. The results for a 1D Poisson's equation show that the DRBFN and the IRBFN procedures achieve a norm of error of at least O(1.0 x 10(-4)) and O(1.0 x 10(-8)), respectively, with a centre density of 50. Similarly, the results for a 2D Poisson's equation show that the DRBFN and the IRBFN procedures achieve a norm of error of at least O(1.0 x 10(-3)) and O(1.0 x10(-6)) respectively, with a centre density of 12 X 12.

Models, Biological↗
PubMed2005

A clockwork hypothesis: synaptic release by rod photoreceptors must be regular.

We can see at light intensities much lower than an average of one photon per rod photoreceptor, demonstrating that rods must be able to transmit a signal after absorption of a single photon. However, activation of one rhodopsin molecule (Rh*) hyperpolarizes a mammalian rod by just 1 mV. Based on the properties of the voltage-dependent Ca2+ channel and data on [Ca2+] in the rod synaptic terminal, the 1 mV hyperpolarization should reduce the rate of release of quanta of neurotransmitter by only 20%. If quantal release were Poisson, the distributions of quantal count in the dark and in response to one Rh* would overlap greatly. Depending on the threshold quantal count, the overlap would generate too frequent false positives in the dark, too few true positives in response to one Rh*, or both. Therefore, quantal release must be regular, giving narrower distributions of quantal count that overlap less. We model regular release as an Erlang process, essentially a mechanism that counts many Poisson events before release of a quantum of neurotransmitter. The combination of appropriately narrow distributions of quantal count and a suitable threshold can give few false positives and appropriate (e.g., 35%) efficiency for one Rh*.

Calcium Channels↗
PubMed2000

The probability of a cancer cluster due to chance alone.

We propose to use a very simple model to test whether a cancer cluster is due to chance alone. We focus on the acute childhood leukaemia cluster in Columbus, Ohio. In 1975, 12 leukaemia cases were observed in Columbus while the expected number is 6 cases per year. According to our simple model, the probability of such an occurrence, due to chance alone, is less than 1 per cent. However, if we divide the child population of the U.S.A. into 200 regions (each region having 200 000 children) then the probability that at least one region will see, in a given year, 12 or more cases is higher than 80 per cent. So in this sense the Columbus cluster could be attributed to chance alone. However, the probability that any of the 200 regions see 18 cases or more in a given year is almost 0. Thus, a cluster of 18 or more cases in a region of 200 000 children should be regarded as highly suspicious and should be investigated.

Acute Disease↗
PubMed2005

A survey of teenager unnatural deaths in northern Sweden 1981-2000.

OBJECTIVE: To survey unnatural deaths among teenagers in northern Sweden and to suggest preventive measures. SETTING: The four northernmost counties (908,000 inhabitants, 1991), forming 55% of the area of Sweden. MATERIAL AND METHODS: All unnatural teenager deaths from 1981 through 2000 were identified in the databases of the Department of Forensic Medicine in Umea, National Board of Forensic Medicine. Police reports and autopsy findings were always studied, social and hospital records if present. RESULTS: Three hundred and fifty-five deaths were found, of which 267 (75%) were males and 88 (25%) females. Ninety out of 327 (28%) tested positive for alcohol. Two hundred and forty-eight (70%) were unintentional and 102 (30%) were intentional deaths, and five (1%) were categorized as undetermined manner of death. Unintentional deaths decreased while the incidence of intentional deaths remained unaffected by time. CONCLUSIONS: Injury-reducing measures have been effective concerning unintentional deaths and the fall in young licensed drivers due to the economical recess have probably also contributed to the decrease. However, there were no signs of decreasing numbers of suicides during the study period, which calls for resources to be allocated to suicide prevention.

Adolescent↗
PubMed2003

Implementation of a clinical dementia guideline. A controlled study on the effect of a multifaceted strategy.

OBJECTIVE: To assess the impact of a multifaceted implementation strategy aiming to improve GP adherence to a clinical guideline on dementia. DESIGN: Controlled before and after study using data records from regional laboratories. The guideline was mailed to all GPs. The multifaceted implementation strategy was planned with local GPs, and consisted of seminars, outreach visits, reminders and continuing medical education (CME) small group training. SETTING: Primary health care. SUBJECTS: 535 GP practices with 727 physicians in Denmark. MAIN OUTCOME MEASURES: The diffusion and use of the guideline was measured by a mailed survey. Adherence to guideline recommendations was monitored by data on laboratory tests from general practice in patient's > or = 65 years: thyroid stimulating hormone requested with vitamin B12 or methylmalonate. The use of these tests as part of a diagnostic evaluation of dementia was subsequently verified by a questionnaire to the practices. RESULTS: Of the GPs who read the guideline, 88% found it applicable in primary care. No increase in the adherence to guideline recommendations was observed regarding the use of laboratory tests or cognitive tests in the diagnostic evaluation of dementia in general practice. CONCLUSION: Although GPs regarded the guideline applicable in primary care, no change in practice adherence to guideline recommendations was detected after a multifaceted implementation.

Chi-Square Distribution↗
PubMed2001

Changing causes of death in the West African town of Banjul, 1942-97.

OBJECTIVE: To determine trends in the causes of death in a West African town. Mortality caused by infectious diseases is reported to be declining while degenerative and man-made mortality factors are increasingly significant. Most mortality analyses for sub-Saharan Africa have involved extrapolation and have not been derived from community-based data. METHODS: Historical data on causes of death coded by physicians were analysed for the urban population of Banjul for the period 1942-97. As the calculation of rates is not possible in the absence of a reliable population denominator, age-standardized proportional mortality ratios (PMRs) for men and women by major groups of causes of death were calculated, using the 1942-49 data for reference purposes. FINDINGS: Most deaths were attributable to communicable diseases. There was a shift in proportional mortality over the study period: the contribution of communicable diseases declined and that of noncommunicable diseases and injuries increased. These trends were more marked among men than women. CONCLUSION: The data illustrate that while noncommunicable diseases and injuries are emerging as important contributors to mortality in sub-Saharan Africa, communicable diseases remain significant causes of mortality and should not be neglected.

Adult↗
PubMed2003

High pregnancy rates and reproductive health indicators among female injection-drug users in Vancouver, Canada.

OBJECTIVE: To determine the incidence of pregnancy among active injection-drug users and to identify factors associated with becoming pregnant. METHODS: The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study that began in 1996. Women who had completed a baseline and at least one follow-up questionnaire between June 1996 and January 2002 were included in the study. Parametric and non-parametric methods were used to compare characteristics of women who reported pregnancy over the study period with those who did not over the same time period. RESULTS: A total of 104 women reported a primary pregnancy over the study period. The incidence of pregnancy over the follow-up period was 6.46 (95% confidence interval (CI) 5.24-7.87) per 100 person-years. The average age of women who reported pregnancy was younger than that of women who did not report pregnancy (27 vs. 32 years, p < 0.001). Women of Aboriginal ethnicity were more likely to report pregnancy (odds ratio 1.6, 95% CI 1.0-2.5). Comparison of drug use showed no significant differences in pregnancy rate with respect to the use of heroin, cocaine or crack (p > 0.05). In examining sexual behavior, women who reported having had a regular partner in the previous 6 months were three times more likely to have reported pregnancy. Despite the fact that 67% of women in this study reported using some form of contraception, the use of reliable birth control was low. Only 5% of women in our study reported the use of hormonal contraceptives. CONCLUSION: There were a high number of pregnancies among high-risk women in this cohort. This corresponded with very low uptake of reliable contraception. Innovative strategies to provide reproductive health services to at-risk women who are injecting drugs is a public health priority.

Adult↗
PubMed1991

Modelling sub-binomial variation in the frequency of sex combinations in litters of pigs.

In some samples of pig litters, the number of males per litter exhibits significant sub-binomial dispersion: there are fewer unisexual and more "sex-balanced" litters than expected under a binomial model. It is argued here that the explanation is that the sex of zygotes may be subject to hormonal control with the consequence that, within a litter, the zygotes do not all have the same probability of being male. This variation in probability is approximated by a quadratic function of the time during oestrus that a zygote is formed so as to parallel the variation in maternal hormone levels. Other explanations are examined briefly, but each seems to have serious weaknesses.

Analysis of Variance↗