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PubMed2001

Task profile and risk of occupational hepatitis A infection in sewerage workers.

OBJECTIVE: The aim of the study was to assess to what extent parameters of task-related occupational exposure influence anti-hepatitis A virus (anti-HAV) seroprevalence in sewerage workers, using a new instrument for classification of exposure. METHODS: A new instrument for the assessment of work-related infection hazards was developed based on expert interviews, evaluation of literature and theoretical considerations. It was included in a questionnaire for collecting detailed information on occupational exposure, safety awareness, safety behaviour and socio-demography. Anti-HAV status was assessed for all (n = 343) (non-vaccinated) study participants. RESULTS: Marked differences in task profile and task-related exposure within the group of sewerage workers were found, underlining the necessity of a detailed exposure analysis. In a multivariate model three risk factors that were related significantly to anti-HAV positivity were identified: age, country of origin and task-related exposure. CONCLUSIONS: Since task profiles and occupational exposure differ strongly within the job category of sewerage workers. evaluation of endangerment has to reflect individual task-related exposure. The task-exposure matrix developed and presented in this study is a practicable and valid instrument for exposure assessment and may be used for the exposure analysis of further biological agents in this working environment. Besides the known risk parameters age and origin, our study demonstrates a dose-response relationship between the degree of occupational exposure and the anti-HAV seroprevalence. Therefore, an effective worksite HAV-prevention programme should consider all technical, structural and educational measures that help to reduce individual exposure.

Adult↗
PubMed2006

Thirty years of the Union of National European Paediatric Societies and Associations (UNEPSA).

BACKGROUND: The Union of National European Paediatric Societies and Associations was founded in 1976 in Rotterdam. Thirty years later, the authors--former presidents and secretaries general--present a retrospective on the activities and achievements of UNEPSA. In 2006, 36 of 46 (78%) European countries, including some countries of the former Soviet Union, were members of UNEPSA. UNEPSA has created a forum for the mutual discussion of matters concerning paediatrics. UNEPSA is closely linked with the International Pediatric Association (IPA). It was never UNEPSA's ambition to promote a uniform European paediatrics. In the 30 years of its existence, it became clear that the diversity of paediatric care in different countries in Europe is extreme. During the "cold war", UNEPSA was able to cross boundaries between socialist and capitalist countries in Europe, and it was due to the activity of individual members of the UNEPSA council that clinical co-operation and research activities were initiated crossing many political borders. Annual meetings of national paediatric presidents focus on the most urgent problems of paediatric health care. "Europaediatrics" became the tri-annual congress for all general paediatricians and paediatric sub-specialists in Europe. The main research activities of UNEPSA concentrated on identifying the demography of primary, secondary and tertiary care paediatrics in Europe. CONCLUSION: UNEPSA is an active paediatric association representing more than three quarters of all European countries. After 30 years, it is still an expanding and vital instrument in improving the medical care of all children and the co-operation of their carers in Europe.

Europe↗
PubMed2005

Signature of recent historical events in the European Y-chromosomal STR haplotype distribution.

Previous studies of human Y-chromosomal single-nucleotide polymorphisms (Y-SNPs) established a link between the extant Y-SNP haplogroup distribution and the prehistoric demography of Europe. By contrast, our analysis of seven rapidly evolving Y-chromosomal short tandem repeat loci (Y-STRs) in over 12,700 samples from 91 different locations in Europe reveals a signature of more recent historic events, not previously detected by other genetic markers. Cluster analysis based upon molecular variance yields two clearly identifiable sub-clusters of Western and Eastern European Y-STR haplotypes, and a diverse transition zone in central Europe, where haplotype spectra change more rapidly with longitude than with latitude. This and other observed patterns of Y-STR similarity may plausibly be related to particular historical incidents, including, for example, the expansion of the Franconian and Ottoman Empires. We conclude that Y-STRs may be capable of resolving male genealogies to an unparalleled degree and could therefore provide a useful means to study local population structure and recent demographic history.

Chromosomes, Human, Y↗
PubMed2004

Linkage disequilibrium between microsatellite markers in the Swedish Sami relative to a worldwide selection of populations.

The pattern of linkage disequilibrium (LD) is affected by a number of factors, including population demography. High LD is seen in populations with a relatively limited and constant size, presumably because of genetic drift. We have examined the extent of LD among over 300 genome-wide pattern microsatellite loci in 29 populations from around the world. The pattern of LD varied between populations, with a larger extent of LD in populations with limited size relative to larger populations. In addition, the LD between 88 less well-spaced microsatellite markers from 10 different genomic regions was examined in the Sami compared with the general Swedish population. For these markers, increased LD extending up to 5 Mb was detected in the Sami. The amount of LD also differed between the chromosomal regions. The amount of LD in the Sami makes this population suitable for the mapping of complex genetic traits.

Genetic Markers↗
PubMed2003

Shrub spatial aggregation and consequences for reproductive success.

To link spatial patterns and ecological processes, we analysed the distribution of two shrub species (one large and dominant, the other smaller) and estimated the reproductive consequences of their distribution for the smaller species. We tested the significance of the spatial distribution pattern of the two shrubs by second-order bivariate point pattern analysis (Ripley's K function). Performance of Asparagus albus, the smaller shrub, was measured as (1) survival of transplanted seedlings in two contrasting habitats: patches of the dominant shrub (Ziziphus lotus), and open interspaces; and (2) reproductive output of plants naturally occurring in both habitats. The two species were significantly aggregated. Transplanted Asparagus albus seedlings had higher survival rates in patches than in the open. Plants produced more flowers, fruits, and showed a higher mass of seeds when living in aggregates than when isolated. The mechanisms responsible for this facilitative effect seem to be related to soil enrichment in patches. These results suggest that the spatial aggregation of species can be indicative of a positive interaction among them, directly affecting fitness of at least one of the species. Facilitation, by inducing variations in the reproductive performance may play a major role in the demography and dynamics of plant populations.

Asparagus Plant↗
PubMed2003

Functional correlates of leaf demographic response to gap release in saplings of a shade-tolerant tree, Elateriospermum tapos.

For a shade-tolerant SE Asian tropical tree, Elateriospermum tapos (Euphorbiaceae), we studied field-established saplings in gaps and the shaded understory to test the hypothesis that differences in leaf demography and leaf life span under contrasting light regimes should be functionally correlated with architecture, self-shading and nitrogen distribution within the sapling crown. Rates of leaf production and net leaf gain were greater for saplings in gaps than those in the understory. Median leaf life span was approximately 26 months in the gap saplings, while it was estimated to be greater than 38 months in the understory saplings. Consequently, gap saplings had a greater standing leaf number and experienced greater degrees of self-shading than understory saplings. Light availability at individual leaves, estimated by a combination of canopy photos and a three-dimensional architecture model, were negatively correlated with leaf age in gap saplings but not so in understory saplings. Leaf nitrogen content per unit area (Narea) was influenced more by light availability than by leaf age in the gap saplings. In contrast, in understory saplings, Narea was neither correlated with light availability nor with leaf age, and did not decrease significantly before 38 months in leaf age. We conclude that saplings of this shade-tolerant species apparently prolong their leaf life span in the shaded understory through slower rates of leaf production, lower standing number of leaves and lower degrees of self shading than in gap, and that the rate of decline of Narea with leaf age depends on architecture and self-shading regimes that respond to changes in light regimes.

Adaptation, Physiological↗
PubMed2003

Regeneration of Rhizophora mangle in a Caribbean mangrove forest: interacting effects of canopy disturbance and a stem-boring beetle.

Current theory predicts that in low-density, seed-limited plant populations, seed predation will be more important than competition in determining the number of individuals that reach maturity. However, when plant density is high, competition for microsites suitable for establishment and growth is expected to have a relatively greater effect. This dichotomous perspective does not account for situations in which the risk of seed predation differs inside versus outside recruitment microsites. We report the results of a field experiment and sampling studies that demonstrate such an interaction between microsite quality and the risk of propagule predation in mangrove forests on the Caribbean coast of Panama, where it appears to play a key role in shaping the demography and dynamics of the mangrove, Rhizophora mangle. Rhizophora's water-borne propagules establish wherever they strand, but long-term sampling revealed that only those that do so in or near lightning-created canopy gaps survive and grow to maturity. These microsites afford better growth conditions than the surrounding understory and, as importantly, provide a refuge from predation by the scolytid beetle, Coccotrypes rhizophorae. This refuge effect was confirmed with a field experiment in which Rhizophora seedlings were planted at different positions relative to gap edges, from 5 m inside to 20 m outside the gap. Mortality due to beetle attack increased linearly from an average of 10% inside a gap to 72% at 20 m into the forest. The interaction between canopy disturbance and propagule predation may be having a large impact on the composition of our study forests. Being shade-tolerant, Rhizophora seedlings that escape or survive beetle attack can persist in the understory for years. However, the high rate of beetle-induced mortality effectively eliminates the contribution of advance regeneration by Rhizophora saplings to gap succession. This may explain why the shade-intolerant mangrove, Laguncularia racemosa, is able to co-dominate the canopy in low intertidal forests at our study sites.

Animals↗
PubMed2003

An examination of a compensatory relationship between food limitation and predation in semi-domestic reindeer.

A central issue in ecology is to what extent food limitation and predation affect animal populations. We studied how survival and reproductive success was related to the female's size in a population of semi-domesticated reindeer during 2 years where there was a large difference in snowfall during winter. The females were kept within a predator-free enclosure for about 5 weeks during the calving period and thereafter released to their natural summer pastures. Small females were more likely to fail to reproduce and they produced smaller calves than large females. Additionally, small females were more likely to loose their calves due to starvation within the predator-free enclosure and to predators outside the enclosure. Food limitation during the harsh winter appeared to be the major cause of deaths. However, food limitation interacted with predation and led to high calf losses when the females experienced low food availability during the harsh winter. In contrast, predators killed no calves after the mild winter. Apparently, the interaction between predation and food limitation is due to small females favouring their own growth and survival over calf production in summers following harsh winters with food shortage. Our results indicate that a compensatory relationship exists between mortality due food limitation and predation. Thus, the impact of calf predation on reindeer demography and population dynamics may be limited.

Animals↗
PubMed2004

Population resistance to climate change: modelling the effects of low recruitment in open populations.

Isolated populations or those at the edge of their distribution are usually more sensitive to changes in the environment, such as climate change. For the barnacle Semibalanus balanoides (L.), one possible effect of climate change is that unpredictable spring weather could lead to the mismatching of larval release with spring phytoplankton bloom, hence reducing the recruitment. In this paper, model simulations of a variable open population with space limited recruitment were used to investigate the effects of low and zero recruitment on population abundance in S. balanoides. Data for model parameters was taken from an isolated population in the Isle of Man, British Isles. Model simulations with observed frequencies of years with low recruitment showed only small changes in population dynamics. Increased frequencies of low recruitment had large effects on the variation in population growth rate and free space and on population structure. Furthermore, populations with intermediate to high frequencies of low recruitment appeared more sensitive to additional changes in recruitment. Exchanging low recruitment with zero recruitment severely increased the risk of local extinctions. Simulations with consecutive years of low recruitment showed a substantial increase in free space and an increase in the time taken to recover to normal densities. In conclusion, model simulations indicate that variable populations can be well buffered to changes in the demography caused by introduced environmental noise, but also, that intermediate to high frequencies of disturbance can lead to a swift change in population dynamics, which in turn, may affect the dynamics of whole communities.

Animals↗
PubMed2006

Short dry spells in the wet season increase mortality of tropical pioneer seedlings.

Variation in plant species performance in response to water availability offers a potential axis for temporal and spatial habitat partitioning and may therefore affect community composition in tropical forests. We hypothesized that short dry spells during the wet season are a significant source of mortality for the newly emerging seedlings of pioneer species that recruit in treefall gaps in tropical forests. An analysis of a 49-year rainfall record for three forests across a rainfall gradient in central Panama confirmed that dry spells of > or = 10 days during the wet season occur on average once a year in a deciduous forest, and once every other year in a semi-deciduous moist and an evergreen wet forest. The effect of wet season dry spells on the recruitment of pioneers was investigated by comparing seedling survival in rain-protected dry plots and irrigated control plots in four large artificially created treefall gaps in a semi-deciduous tropical forest. In rain-protected plots surface soil layers dried rapidly, leading to a strong gradient in water potential within the upper 10 cm of soil. Seedling survival for six pioneer species was significantly lower in rain-protected than in irrigated control plots after only 4 days. The strength of the irrigation effect differed among species, and first became apparent 3-10 days after treatments started. Root allocation patterns were significantly, or marginally significantly, different between species and between two groups of larger and smaller seeded species. However, they were not correlated with seedling drought sensitivity, suggesting allocation is not a key trait for drought sensitivity in pioneer seedlings. Our data provide strong evidence that short dry spells in the wet season differentially affect seedling survivorship of pioneer species, and may therefore have important implications to seedling demography and community dynamics.

Bombacaceae↗
PubMed2006

Density, climate and varying return points: an analysis of long-term population fluctuations in the threatened European tree frog.

Experimental research has identified many putative agents of amphibian decline, yet the population-level consequences of these agents remain unknown, owing to lack of information on compensatory density dependence in natural populations. Here, we investigate the relative importance of intrinsic (density-dependent) and extrinsic (climatic) factors impacting the dynamics of a tree frog (Hyla arborea) population over 22 years. A combination of log-linear density dependence and rainfall (with a 2-year time lag corresponding to development time) explain 75% of the variance in the rate of increase. Such fluctuations around a variable return point might be responsible for the seemingly erratic demography and disequilibrium dynamics of many amphibian populations.

Animals↗
PubMed2004

Laparoscopic drainage of pancreatic pseudocysts.

BACKGROUND: Laparoscopic drainage of pancreatic pseudocysts (PPs) has been used in selected cases. The aim of this study is to analyze our results with the laparoscopic technique and to compare them with those of a cohort of patients treated by open surgery during the same time period. PATIENTS AND METHODS: Ten patients underwent laparoscopic drainage of PPs during a 7-year period [laparoscopic group (LG)]. The type of drainage was chosen according to the size and location of the PP. Demography, surgical details, results, and complications were analyzed and contrasted with those of 6 patients who underwent open drainage [open group (OG)]. RESULTS: All patients presented with mature PPs developed after a documented episode of acute pancreatitis. Mean age of the LG was 42 years (six males and four females). In the OG, mean age was 36 years (five males and one female). Etiology of the pancreatitis was alcoholic in eight patients, biliary in five, toxic in two, and associated with systemic lupus erythematous in one. Laparoscopic procedures included Roux-en-Y cystojejunostomy in four patients, extraluminal cystogastrostomy in four, and intraluminal cystogastrostomy in two. There were no conversions. In the OG, cystogastrostomy was performed in three patients and Roux-en-Y cystojejunostomy in three. One patient in the LG developed upper gastrointestinal bleeding the day after surgery that resolved uneventfully, one patient presented a postoperative abscess that required open drainage, and one patient presented a residual pseudocyst that was treated by endoscopy. Morbidity in the OG included a small bowel obstruction secondary to an internal hernia that required reoperation, pneumonia, and a residual pseudocyst that was treated conservatively in one patient each. At a median follow-up of 22 months (range, 1-72) all patients were asymptomatic with no evidence of recurrent disease by computed tomography scan. CONCLUSION: Laparoscopic drainage of PPs is feasible, safe, and effective. Results are similar to those obtained using the open technique.

Adolescent↗
PubMed2006

Global quality of life in primary caregivers of patients with cancer in palliative phase staying at home.

GOAL OF WORK: Research on global quality of life (GQOL) in primary caregivers (PCGs) of cancer patients is limited. This study measured significant domains of GQOL in PCGs and their association with the patients' disease trajectory and the PCGs' background and life situation. This study also explored differences in their GQOL compared to a normative sample from the general population (NORM). PATIENT AND METHODS: In a cross-sectional design, 71 PCGs (aged > or = 50 years) of cancer patients in palliative phase rated their GQOL by the Quality of Life Scale (QOLS) and provided information concerning demography, experienced social support, and caring situation. Associations between the QOLS scores and variables of the patients' medical history were assessed, and comparisons of QOLS scores were made between the PCGs and age- and gender-adjusted NORM. MAIN RESULTS: Long duration of the curative phase for patients and holding a job for PCGs were significantly associated with a favorable GQOL in PCGs. The mean total GQOL score did not differ significantly between the PCGs and NORM groups, though subanalyses revealed significantly more favorable mean score of the relational domain in PCGs compared to NORM. CONCLUSIONS: GQOL in PCGs of cancer patients in palliative phase staying at home was as good as that of the NORM. For PCGs not employed or caring for patients with a short curative phase, getting some recreation could be of importance for improvement of GQOL.

Adaptation, Psychological↗
PubMed2005

The mycorrhizal community in a forest chronosequence of Sitka spruce [Picea sitchensis (Bong.) Carr.] in Northern England.

Demography and fungal diversity of the belowground ectomycorrhizal community in a chronosequence of Sitka spruce [Picea sitchensis (Bong.) Carr.] in Northumberland, Northern England, were analysed; mycorrhizal root samples were taken from 6-, 12-, 30- and 40-year-old stands, and fungal fruiting bodies were collected in autumn to complement the survey. Naturally germinated seedlings less than 1 year of age (taken from the 30-year-old stand) were also examined. A total of 118,000 mycorrhizal root tips were extracted from 40 soil cores (ten per age class) and from the complete root systems of 25 seedlings and separated into active and senescent root tips according to their morphology and anatomy. Active tips were distinguished according to their mycobionts which were characterised and identified microscopically. Although almost 100% of all fine roots were mycorrhizal, EM fungal diversity throughout the chronosequence was low, consisting of a total of 16 species of which three were only found as fruiting bodies. Of the six mycobionts found most regularly below ground, Tylospora fibrillosa was the most common, colonising about 70% of all root tips and more than 90% of those of seedlings and young trees. Root density and mycorrhizal diversity increased, but percentage of vital root tips decreased with increasing tree age, levelling off in the 30- and 40-year-old stand. Among the five subdominant fungal species, Dermocybe crocea was found to have its peak of distribution in the 12-year-old stand and Russula emetica, Lactarius rufus, Hymenoscyphus ericae agg. and the unidentified Piceirhiza sulfo-incrustata in the 30- and 40-year-old stands. The possible correlations between the mycorrhizal community structure and biotic and abiotic factors are discussed.

Biodiversity↗
PubMed1999

The European Brain Injury Consortium survey of head injuries.

To provide a picture of contemporary practice, a survey was carried out of severely and moderately head injured patients admitted to 67 'neuro' centres in 12 European countries. 1,005 adult head injuries were recruited over a three month period. Sixty items of information on demography, clinical features, investigations, management and early complications were captured on a simple, two-page questionnaire and, information on outcome at six months on a third page. The median age of the subjects was 38 years, 74% were male and 51% injured in road traffic accidents; 57% of patients were transferred to the 'neuro' centre from another hospital. Assessment of clinical responsiveness was limited by the use of sedation and intubation and information from four early time points (pre-hospital, arrival at the Accident and Emergency department, post-resuscitation, and arrival at the 'neuro' unit) was combined to stratify the subjects as severe (58%), moderate (17%) or intermediate (19%). In 48% of patients classified the CT scan showed features of a 'mass lesion' and in 40% showed a subarachnoid haemorrhage. Fifty-five centres provided the data on outcome for 94% of the cases recruited in these centres six months after injury. 31% died, 3% were vegetative, 16% severely disabled, 20% moderately disabled and 31% had made a good recovery. Comparison of the data from different parts of Europe showed differences in the frequency of secondary transfer, cause of injury, occurrence of major extracranial injury, CT scan findings, intracranial operation, clinical severity of injury and utilisation of the components of intensive care and the occurrence of a favourable outcome, although the latter difference was not statistically significant when variations in the initial severity of injury were taken into account. The findings in the present survey are compared with newly analysed information for three previous large series: the International Data Bank involving the UK, the Netherlands and the USA, the North American Traumatic Coma Data Bank, and data from four centres in the UK. The comparisons showed substantial similarities and also differences that may reflect variations in policy for admission of the head injury to 'neuro' units, and evolution in methods of assessment, investigation and management. The effects of these differences on outcome requires further, rigorous prospective study.

Adolescent↗
PubMed2005

Modelling the spread of scrapie in a sheep flock: evidence for increased transmission during lambing seasons.

Presence of scrapie infectivity in the placenta suggests the possibility of increased transmission of scrapie during the lambing season. This hypothesis was explored here using a mathematical model of scrapie transmission dynamics which has previously been successfully used to study several scrapie outbreaks in Scottish sheep flocks. It was applied here to the Langlade experimental sheep flock (INRA Toulouse, France), in which a natural scrapie epidemic started in 1993. Extensive data were available, including pedigree, scrapie histopathological diagnoses and PrP genotypes. Detailed simulations of the scrapie outbreak reveal that the observed patterns of seasonality in incidence can not be accounted for by seasonality in demography alone and provide strong support for the hypothesis of increased transmission during lambing. Observations from several other scrapie outbreaks also showing seasonal incidence patterns support these conclusions.

Age Factors↗
PubMed2001

Population dynamics of a scrapie outbreak.

A detailed analysis of a scrapie outbreak in a flock of Cheviot sheep is described. A total of 33 cases of 1473 sheep born to the flock were reported between 1985 and 1994. The epidemiology of scrapie can only be understood with reference to sheep demography, the population genetics of susceptibility to scrapie, pathogenesis during a long incubation period, and the rate of transmission (by both horizontal and vertical routes), all of which interact in complex ways. In recent work a mathematical model incorporating these elements was developed and successfully reproduced key features of an earlier outbreak of scrapie in this flock. Here an application of the model to the second outbreak is described. The model accurately reproduces observed allele frequencies and total numbers of susceptible animals remaining at the end of the outbreak. A major difference between the two outbreaks is the very much lower force of infection in the second outbreak. This provided additional information which suggested two ways in which our existing assumptions be refined; firstly, older animals have reduced susceptibility to scrapie and secondly, homozygous and heterozygous susceptibles have different incubation periods.

Animals↗
PubMed2005

A comparison of mental health problems in kinship and nonkinship foster care.

OBJECTIVE: Knowledge of the emotional and behavioural problems of children in kinship foster care is scarce. No data on such problems in European countries have been published. This study compares child psychiatric problems and placement characteristics of children living in kinship and nonkinship foster care. METHODS: A total of 214 children in kinship and nonkinship foster care, aged 4-13, participated in the study. The Child Behavioral Checklist (CBCL) was completed by their foster parents and demography and placement information was collected. RESULTS: Of the nonkinship group, 51.8 % scored above the borderline on the CBCL Total Problem score, as did 35.8% of the kinship group. The kinship group had fewer previous placements, were more often fostered within their local community and had more contact with their biological parents. Kinship foster parents had lower social status, in terms of educational level. Variables significantly related to high level of the CBCL Total problems score were male gender and location of foster home outside community of birth family. Positive outcome was significantly associated with placement within the child's own community, which in turn was related to kinship placement. CONCLUSIONS: Placement in kinship foster care should be considered as a viable possibility.

Adolescent↗