The present study investigated the development and dispersal of bagworm larvae, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae), on three hosts: arborvitae, Thuja occidentalis, blue ...spruce, Picea pungens, and juniper, Juniperus virginiana. The biomass of larvae was recorded at repeated intervals at 21 field sites. The relative quality of plants varied during larval development: early in the season, larvae were heavier on juniper and arborvitae than on blue spruce; late in the season, in contrast, larvae and pupae were lighter on juniper than on the two other plants. Larvae on blue spruce pupated later than those on arborvitae. In the laboratory, feeding rate and larval growth were not influenced by the density of larvae on the foliage of arborvitae up to a range which greatly exceeded that observed at any of our experimental sites. The incidence of dispersal among neonates emerging on arborvitae was high, as indicated by the high number of larvae captured on sticky traps, and the relatively low number of early instars on arborvitae foliage in relation to the reproductive output of females in the parental generation. The high rate of dispersal among early instars may be due to potential resource depletion over successive generations of bagworms.
Background: The suntanning industry has grown up over the last decade in North America, mainly because tanned skin is socially desirable and artificial tanning is perceived as a “safe tan.” However, ...exposure to UV radiation is known to cause adverse health effects.
Objective: The purpose of this study was to estimate the prevalence of use of tanning equipment in the Province of Québec and to characterize people who reported using these devices.
Methods: In 1996, a telephone survey was carried out among adults from the two most densely populated regions (Montréal, Québec) of the Province of Québec. The final sample included 1003 white persons 18 to 60 years old. Interviewers used a standardized questionnaire to document the characteristics of the participant, skin phototype, and exposure habits to artificial UV radiation sources.
Results: During the last 5 years before the survey, 20.2% of the respondents reported they had used, at least once, a tanning device in a commercial tanning salon. The rate of use during the last 12 months before the study was 11.1%. A significantly higher proportion of female, young people (18 to 34 years old) and single persons was found among tanning bed users. Twenty-six percent of users experienced one or more acute adverse health effects from the artificial UV irradiation. Most of these were cases of skin burns. A high proportion (77.5%) of those who used tanning equipment during the last year before the study said they would return to tanning salons. The intention of returning to a tanning salon was not influenced by the occurrence of the acute adverse health effects. The most prevalent reason given for using tanning equipment was “to improve their appearance by a tan.” Most people (60.4%) who used a tanning bed during the last 5 years before the study believe that tanning salons are not dangerous.
Conclusion: This survey indicates that tanning bed use is very prevalent in the Province of Québec, mainly among young women. The high rate of acute adverse health effects related to artificial tanning, particularly skin burns, is of concern. Finally, our results underline the importance of changing attitudes and beliefs in the population regarding artificial tanning. (J Am Acad Dermatol 1999;40:572-6.)
Analyses completed on samples collected between 1993 and 1996 showed that about 7% of 475 Inuit newborns from northern Quebec (Canada) had a cord blood lead concentration equal to or greater than ...0.48 μmol/l, an intervention level adopted by many governmental agencies. A comparison between the cord blood lead isotope ratios of Inuit and southern Quebec newborns showed that lead sources for these populations were different. Our investigation suggests that lead shots used for game hunting were an important source of lead exposure in the Inuit population. A cohort study conducted in three Inuit communities shows a significant decrease of cord blood lead concentrations after a public health intervention to reduce the use of lead shot. Lead shot ammunition can be a major and preventable source of human exposure to lead.
Abstract
The aim of this study is to evaluate the utilisation of CSRs by Quebec's local health technology assessment (HTA) units to promote efficiency in hospital decision-making. A survey was ...conducted using a structured online questionnaire to examine: Characteristics of the HTA units; Knowledge about works and services from the Cochrane Collaboration; Level of satisfaction about the use of CSRs; Facilitating factors and barriers to the implementation of CSRs evidence in a local context; Suggestions to improve the use of CSRs. Data accuracy was checked by two independent evaluators (TGP and CAB). Ten HTA units participated. Mean number of staff was 6.3 2-18, producing about 4.7 reports per year 2-7.3. From their implementation a total of 321 HTA reports were published (49.8% included a SR). Works and services provided by the Cochrane collaboration were very well known and HTA units were highly satisfied with CSRs (80-100%). However, only 24.7% (21/85) of topics were searched with success. As regards to applicability in HTA and use of CSRs, major strengths were as follow: Useful as resource for search terms and background material; May reduce the workload (e.g. brief review instead of full SR); Use to update a current review. Major weaknesses were: Limited use since no CSRs were available for many HTA projects; Difficulty to apply findings to local context (lack of contextualisation); Focused only on efficacy and innocuity; Cannot be used as a substitute to a full HTA report. This study provided a unique context of assessment with a familiar group of producers, users and disseminators of CSRs in hospital setting. HTA units generally use other articles from the literature or produce an original systematic review in complement with CSRs. These results led to some suggestions to improve the use of CSRs by HTA units. However, the main limit for the use of CRS in local HTA will remain its lack of contextualisation.
Key messages
The main limit for the use of CRS in local HTA will remain its lack of contextualization. Context and scientific data are complementary.
The purpose of this study was to evaluate the effect of cigarette smoking (active and passive exposure) and alcohol consumption during pregnancy on cord blood lead levels. In 1990, a survey was ...conducted in two hospitals in Quebec City, Quebec, Canada, a white-collar agglomeration. The sample included 430 mothers and their newboms. Information on the lifestyles of mothers during pregnancy was obtained by questionnaire. Cord blood lead concentrations were measured by atomic absorption spectrophotometry. A dose-response relation was found between cigarette smoking and alcohol consumption of mothers and cord blood lead levels. An average increase of about 15 percent (0.013 μmol/liter) in cord blood lead levels was estimated for every 10 cigarettes smoked per day. Mean blood lead levels in babies whose mothers did not smoke dunng pregnancy but who drank alcohol moderately was 17 percent higher than those of nonsmoking mothers who abstained from alcohol intake. Multivariate analyses revealed that both cigarette smoking and alcohol intake make significant and independent contnbutions to cord blood lead concentrations. Lifestyles of pregnant women thus appear to play an important role in the prenatal lead exposure of newborns. Because of the potential effects of lead exposure on pregnancy outcomes, our study provides further arguments to support public health advisories concerning the harmful effect of smoking and drinking alcohol during pregnancy Am J Epidemiol 1997, 145: 250-7
A study carried out across 33 weeks in a patch of taro, Colocasia esculenta L., quantified demographic parameters and density-dependent processes for a population of melon aphid, Aphis gossypii ...Glover. Variation in relative density of aphids per square cm of leaf tissue between consecutive weeks declined with the initial density of aphids, indicating that density dependent processes regulate populations of A. gossypii on taro. High abundance of aphids on large leaves suggest that host attributes affect the rates of colonization or reproduction of adults. Even though the incidence of winged aphids was consistently low throughout the experiment, between plant dispersal by aphids still homogenizes their spatial distribution within an array of plants, as indicated by similar relative densities of aphids on established plants and on sentinel (initially uninfested) plants 60 days following their introduction in the patch. The proportion of aphids parasitised by Aphidius colemanii Viereck and Aphelinus spp. was low (<3%), which may be attributed to a high level (>95%) of hyperparasitism. Mortality caused by two entomopathogens, Neozygites fresenii Nowakowski and Verticillium lecanii Zimmerman, averaged 12%. The proportion of fungal infection increased with the density of aphids, both on a spatial and temporal scale. However, the population of A. gossypii on taro was most likely not regulated by entomopathogens, because the proportion of diseased aphids did not influence variations of population density between consecutive weeks. The lower proportion of fungal infection on sentinel plants than on established plants suggests a limited impact of entomopathogens on taro plants recently colonized by aphids.
A study conducted in a Malaysian plantation of oil palm over 5 consecutive generations of bagworms, Metisa plana (Walker) (Lepidoptera: Psychidae), evaluated extent and causes of variability for 3 ...components of reproductive success: pupal mortality, mating success and fecundity. The population of M. plana in the experimental site exhibited cycles of 70–80 days with discrete generations. Females emerged before males during all generations. Relatively large proportions of M. plana did not reproduce, either because they did not survive as pupa or (for females) mate as adult. Occurrence of unmated female bagworms may be attributed to complex mating procedure, short lifespan of females, limited mating capacity of males, protogyny inducing female‐biased operational sex‐ratio, and/or flightlessness per se constraining mating success of females. Size attained at pupation is a significant component of reproductive success, with large individuals having greatest survival during pupal stage, mating success and fecundity. Population density also influenced reproductive success of M. plana: female and (to a lesser extent) male larvae on crowded palms attained small size at pupation; survival of pupae was density‐dependent during 2 generations for females and density‐independent during 5 generations for males; mating success of females was inverse density‐dependent during 4 generations. Size‐ and density‐dependent mating success of females may be attributed to mate choice by males, size‐dependent pheromone production by and longevity of females, and/or disorientation of mate‐seeking males around heavily infested palms. Long‐term studies are needed to determine whether and to what extent attributes of oil palm, seasonal fluctuations of abiotic factors and inter‐generational variations of reproductive success influence population dynamics of M. plana.
"The unusual life history of bagworms, Metisa plana (Lepidoptera: Psychidae), with females completing all reproductive activity within a bag they construct as larvae, makes them ideal subjects to ...quantify intraspecific variations of reproductive success. This study investigated the relationship between body size and reproductive output of females, and tested the hypothesis that size-dependent variations of fecundity affect inter-generational variations of population density. Body size attained by female larvae at pupation (assessed by measuring the length of the pupal bag) was positively correlated with several parameters of reproductive output, including weight of pupae, weight and potential fecundity of calling female, as well as weight and realized fecundity of mated females. Our results further suggest that females allocate about two thirds of the resources they accumulate as larvae into egg production, and that a significant proportion of eggs are cannibalized by sibling neonates. In cage experiments, density of larvae in offspring generations on individual nursery palms was not affected by the size of females in parental generations. This result suggests that body size of females may not affect inter-generational variations of population density when potential resource depletion of host plants promotes a high incidence of dispersal among neonates."
Seafood consumption during pregnancy carries both benefits (high n−3 FA intake) and risks (exposure to environmental contaminants) for the developing fetus. We determined the impacts of marine n−3 FA ...and environmental contaminants on gestational age (GA) of Nunavik women and the anthropometric characteristics of their newborns. FA and contaminant (polychlorinated biphenyls and mercury) concentrations were measured in cord plasma of Nuvavik newborns (n=454) and compared with those of a group of newborns (n=29) from southern Québec. Data were collected from hospital records and birth certificates. In Nunavik newborns, arachidonic acid (AA) was two times lower (P<0.0001), whereas DHA concentration, the Σn−3/Σn−6 ratio, and the percentage of n−3 highly unsaturated FA (HUFA) (of the total HUFA) were three times higher (P<0.0001) compared with southern Québec newborns. After controlling for confounders, GA and birth weight were higher by 5.4 d 95% confidence interval (CI): 0.7–10.1 and 77 g (95% CI: −64 to 217) in the third tertile of percentage of n−3 HUFA (of the total HUFA) as compared with the first tertile. There was no evidence that contaminants had negative effects on GA or birth weight. In this seafood‐eating population, an increase in the proportion of n−3 HUFA (of the total HUFA), measured in umbilical cord plasma phospholipids, was associated with a significantly longer GA.
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