bluuebunny/crossref_metadata_2025 huggingface dataset:
Age‐specific reproductive performance in red‐billed choughs Pyrrhocorax pyrrhocorax: patterns and processes in a natural population
Authors: Reid J. M. , Bignal E. M. , Bignal S. , McCracken D. I. , Monaghan P.
Published: August 2003

Using data from a 20‐year study of individually marked red‐billed choughs, we examine how reproductive performance varies with age in male and female breeders, and investigate whether population‐level trends result from changes in individual performance and/or the phenotypic composition of the breeding population.

Across the population, mean clutch size, the probability of breeding successfully and the number of offspring fledged during successful attempts increased and then declined with female age. Male age did not explain a significant proportion of the residual variation.

All three measures of reproductive performance improved and then declined with age within individual females.

Females that died young laid relatively small clutches and fledged few offspring before death. Thus mean performance improved across young age classes partly because some poor breeders were absent from older age classes.

Females that ultimately reached the greatest ages had laid small clutches and fledged few offspring during their first few breeding attempts. Females that were more productive when they were young had relatively shorter lives. These data indicate a trade‐off between early reproduction and future survival in choughs, and suggest that individuals that reach old age are phenotypically distinct from an early stage in their breeding lives.

We emphasize that age‐specific changes in mean reproductive performance observed across wild populations are due to a complex interplay between improvement and senescence at the individual level, as well as changes in the phenotypic composition of the breeding population.
Is clutch size limited by incubation ability in northern lapwings?
Authors: Larsen Vegard A. , Lislevand Terje , Byrkjedal Ingvar
Published: August 2003

The incubation‐limitation hypothesis states that clutch size in shorebirds is constrained by the ability to incubate more than four eggs successfully. In order to test predictions from this hypothesis, clutches of northern lapwings (Vanellus vanellus) were here experimentally increased and reduced by one egg at the onset of incubation. Parental behaviour, incubation time, hatching synchrony, egg viability, hatching success and body condition of hatchlings was compared with unmanipulated clutches.

Nest desertion and egg breakage was not observed in any of the experimental nests, showing that clutch enlargement did not alter the parental behaviour adversely.

There were no differences among the experimental groups in male and female attentiveness, but the total nest attentiveness was lower in reduced clutches than in the other clutch sizes; nor did the parents’ frequency of nest visits differ between clutch sizes.

Enlarged clutches were incubated longer than controls and reduced clutches. There were, however, no significant differences among clutch sizes in partial or total clutch predation rates. Hatchability of the eggs (proportion of eggs hatching of those present in nests at the end of incubation) was marginally lower in the enlarged clutches (92·5% vs. 100% in the two other groups).

Contrary to predicted, hatching success was highest in enlarged clutches. The numbers of hatched eggs calculated from Mayfield estimates of daily nest and egg survival rates were 0·93, 2·10 and 3·14 in three‐, four‐ and five‐egg clutches, respectively.

When controlling for egg volume, mean body mass of newly hatched chicks was lower in clutches with five eggs than in other nests.

We suggest that the lowered body condition of chicks could outweigh the benefits of laying five instead of four eggs in northern lapwings. Future studies of the selective mechanisms of clutch size in shorebirds should not only focus on the number of young that hatch, but also their quality.
Population stability in salmon species: effects of population size and female reproductive allocation
Authors: Einum Sigurd , Fleming Ian A. , Côté Isabelle M. , Reynolds John D.
Published: August 2003

Population stability (i.e. level of temporal variation in population abundance) is linked commonly to levels of environmental disturbances. However, populations may also differ in their propensity to dampen or amplify the effects of exogenous forces. Here time‐series of population estimates were used to test for such differences among 104 populations of six salmon species.

At the species level, Atlantic (Salmo salarL.), chinook (Oncorhynchus tshawytschaWalbaum) and coho salmon (O. kisutchW) were less variable than sockeye (O. nerkaW) and pink salmon (O. gorbuschaW). Chum salmon (O. ketaW) was more similar to sockeye and pink salmon. These differences may be related in part to differences in body size, and hence susceptibility to adverse environmental conditions, at the time when they migrate to the sea or lakes.

At the population level no effect of fecundity on variability was found, in contrast to findings for marine fishes, nor of egg size. Whereas substantial differences in the temporal stability of environmental factors among geographically close populations may over‐ride any effects of fecundity or egg size in fresh water, this is less likely in the marine environment where spatial autocorrelations of environmental variability are more pronounced.

Variation in population sizes was related positively to the duration of time‐series when using standard deviations of ln‐transformed population estimates, and also when using linearly detrended population variation, suggesting non‐linear long‐term abundance trends in salmon populations that extend beyond the 7‐year period of the shortest time‐series.

When controlling for differences among species, stability increased with increasing population size, and it is hypothesized that this is due to large populations having a more complex spatial and genetic structure than small populations due to wider spatial distribution. The effects of population size on stability, as well as differences in stability among species, suggest that population‐ and organism‐specific characteristics may interact with exogenous forces to shape salmon population dynamics.
Mass provisioning to different‐sex eggs within the laying sequence: consequences for adjustment of reproductive effort in a sexually dimorphic bird
Authors: Blanco Guillermo , Martínez‐Padilla Jesús , Serrano David , Dávila José A. , Viñuela Javier
Published: August 2003

In birds, the potential maternal ability to adjust resource allocation to different eggs in the clutch might have a major effect on the survival expectancies of particular nestlings or entire broods. We assessed whether sexually size‐dimorphic Eurasian kestrels Falco tinnunculus (Linnaeus) are able to adjust their reproductive effort by adopting different strategies of egg mass provisioning according to egg sex and laying order.

Initial eggs bearing male embryos were heavier than initial eggs bearing female embryos, but no differences in egg mass associated to sex were detected for eggs laid subsequently. Furthermore, in clutches started with a male egg, egg mass declined in subsequent eggs, while in clutches started by a female egg the opposite trend in within‐clutch egg‐mass variation was found. This suggests differential deposition of resources invested in initial eggs of different sex leading to saved or depleted resources for subsequent eggs.

Daughters from initial eggs hatched earlier than sons from initial eggs, which may enhance survival of smaller siblings hatched later. These contrasting strategies of egg provisioning and hatching patterns depending on the sex of the first‐laid egg were associated, respectively, with marked mass hierarchies and a lack of mass hierarchies at fledgling in broods initiated with eggs bearing sons and daughters.

Parental kestrels may allocate reproductive effort by promoting favouritism towards early hatched chicks or by avoiding any favouritism by producing siblings of each sex with similar mass. This may be achieved depending on the female ability both to identify egg sex and to partially reabsorb or differentially allocate resources to eggs accordingly to adjust reproductive investment. This may be a key mechanism to control sibling competition in birds with sexual dimorphism in mass.
Effect of experimentally altered food abundance on fat reserves of wintering birds
Authors: Rogers Christopher M. , Heath‐Coss Rejeana
Published: August 2003

Current models of adaptive fat regulation make opposing predictions concerning the effect of increased winter food supply on size of the avian winter fat reserve. To distinguish between models, food supply was varied experimentally in nature and two measures of size of the fat reserve were taken at food‐supplemented sites and non‐supplemented sites.

In two winters, most of the seven species sampled showed slightly higher visible subcutaneous fat class at supplemented than at non‐supplemented sites; treatment and species factors were statistically significant. Body mass corrected for wing length showed a similar if non‐significant trend.

A parallel dispersal study of birds colour‐banded at non‐supplemented sites showed that these birds did not move 0·8 or 1·5 km to use supplemental food at private feeding stations in the study areas. In addition, accipiter hawk attack rate did not differ between supplemented and non‐supplemented sites.

These results are consistent with a model of adaptive fat regulation (based on between‐day environmental variability caused by severe weather events) that predicts an increase in the winter fat reserve at increased food supply. Other published studies, all from the north temperate zone, showed the same pattern.

The present results are inconsistent with a second model (based on within‐day foraging interruption) which predicts a decrease in the fat reserve under increased food supply. However, a set of published studies, all from tropical regions or regions with mild maritime climate, showed the decrease at higher food predicted by the second but not the first model.

Models of adaptive fat regulation in small birds are therefore limited in their predictive power, perhaps because they are developed for environments that differ in the time scale of environmental stochasticity. New studies are needed that explore further the complexities of environment‐specific adaptive fat models, e.g. a winter feeding experiment in a tropical bird species.
Differential body condition regulation by males and females in response to experimental manipulations of brood size and parental effort in the blue‐footed booby
Authors: Velando Alberto , Alonso‐Alvarez Carlos
Published: August 2003

In long‐lived species, such as seabirds, the allocation of resources between self‐maintenance and reproduction is of particular interest because only a small reduction in adult survival may have a large negative effect on lifetime reproductive success. There is much debate about whether seabirds have a fixed or flexible level of investment in their current reproduction, and it has been proposed that parents can regulate the risk of an increase in mortality under the control of a mass threshold.

Body mass change as response to experimental manipulations of parental effort was examined in blue‐footed boobies (Sula nebouxiiMine‐Edwards), a sexually size‐dimorphic seabird, with females approximately 31% heavier than males.

First, paternal effort was manipulated by trimming the flight feathers and thereby handicapping males during the chick‐rearing period. Mass remained stable in handicapped males, while there was a reduction of female body mass as response to the handicapped partner. The handicapping of males had a significant effect on chick mass.

Secondly, an experiment was made by enlarging and decreasing broods of two chicks to three and one during the first week after hatching. Body mass of females, but not males, was lower in enlarged broods, and body mass of males, but not females, was higher in the reduced broods when the chicks were 45 days old. Chick body masses were lower among enlarged broods than among reduced and control broods.

Overall, these and other results revealed that blue‐footed boobies have a sex‐specific body mass regulation. Males had a fixed body mass at the end of experiments; they were working at some physiological maximum or were unwilling to pay the cost in terms of future survival, when the effort demanded was increased. Females performed a flexible effort and were working with a buffer of nutritional reserves that they used when necessary. Below a critical level, females preferentially allocated resources to the maintenance of their body condition at the expense of investment in current reproduction.
The effect of weather on lesser kestrel breeding success: can climate change explain historical population declines?
Authors: Rodríguez Carlos , Bustamante Javier
Published: August 2003

We model the effect of annual weather conditions on lesser kestrel Falco naumanni breeding success in South‐western Spain. Models indicate that rainfall is a good predictor of breeding success and has in general a positive effect on reproduction.

Rainfall and temperature in spring, during the courtship period, influence colony occupancy rate. Mean minimum temperatures have a positive effect on nest occupation while the relationship between occupation and rainfall is curvilinear with an optimum around 84 mm.

Nest success rate is influenced positively by rainfall in winter and negatively by rainfall during the nestling period.

The mean number of chicks per successful nest is positively influenced by rainfall during the winter, arrival, courtship, and incubation periods. Rainfall during these periods explains 35% of the variance in this breeding parameter.

Nestling body condition is affected positively by rainfall during the courtship and incubation periods.

Models that consider the amount of rainfall at each colony in periods defined by the breeding phenology of the lesser kestrel outperform those based on total annual rainfall or on winter NAO‐index.

Although rainfall in spring has declined significantly since 1966, retrospective predictions of lesser kestrel population growth rate at our colonies indicate that the effect of climate change on breeding success cannot be held responsible for the historical population decline.
Occupancy as a measure of territory quality
Authors: Sergio Fabrizio , Newton Ian
Published: August 2003

Territory quality may affect individual fitness and contribute to density‐dependent reproduction, with repercussions on population regulation. We investigated the probable causes and population consequences of spatio‐temporal variations in territory quality, measured by occupancy, in eight black kiteMilvus migransBoddaert populations, one of them studied for 10 years (Lake Lugano) and the rest for 4–5 years.

Over a period of years, the occupation rate of territories varied from a random pattern. Some territories were preferred while others were avoided. On return from migration, males and females settled earlier on high‐occupancy territories.

The positive association between territory occupancy and breeding performance held in all years of study at Lake Lugano, and in six of seven tested populations. As a result, high‐occupancy territories contributed most of the young produced by each population.

The occupation rate of the overall 225 territories was related positively to food availability and negatively to mortality risk, measured as proximity to the nearest eagle owlBubo buboLinnaeus nest.

At the population level, spatial variation in mean occupancy was positively correlated with spatial variation in mean productivity, suggesting that mean occupancy could be used as a measure of overall habitat quality and population performance.

In the Lake Lugano area, a higher proportion of low quality territories was occupied in years of higher density and annual productivity was related negatively to its coefficient of variation. However, annual productivity was not related significantly to the proportion of low quality territories occupied, so support for the theory of site‐dependent population regulation was only partial.

In a review of 22 studies of territory occupancy in 17 species, occupancy always deviated from a random pattern in species in which it was tested and was always correlated with productivity and/or with some other measure of territory quality. Our results confirm the importance of prioritizing conservation of high quality territories. Occupancy may be a reliable method of quality assessment, especially for populations in which not all territories are always occupied, or for species in which checking occupancy is easier than finding nests.
Nutrient exchanges between marine and terrestrial ecosystems: the case of the Galapagos sea lion Zalophus wollebaecki
Authors: Fariña J. M. , Salazar S. , Wallem K. P. , Witman J. D. , Ellis J. C.
Published: August 2003

The movement of materials and organisms between ecosystems is a common process in nature.

In the present study we investigate the hypothesis that the transport of nutrients by low‐mobility species and their effect on terrestrial ecosystems depends on habitat topography. Specifically, we hypothesized that the influence of a marine organism with low mobility on terrestrial environments would be spatially restricted.

To address this hypothesis we analysed the distribution (both geographical and local scales) of Galapagos sea lion colonies, and quantified the spatial extent of their influence on terrestrial ecosystems (soil and plants).

Our results showed that the influence of Z. wollebaecki on Galapagos terrestrial habitats is restricted to shorelines with low elevations, but that it is it is geographically ubiquitous across the Archipelago.

Our study demonstrated that Z. wollebaecki is an effective vector for the transport of marine nutrients to terrestrial ecosystems. Transported nutrients occur in high concentrations in the soils and are used by shoreline plants. These effects are spatially restricted to the areas where seals occur and the most parsimonious explanatory variable for these patterns is the islands’ topography (or elevation).
The Prudhoe Cognitive Function Test, a scale to assess cognitive function in adults with Down's syndrome: inter‐rater and test–retest reliability
Authors: Margallo‐Lana M. L. , Moore P. B. , Tyrer S. P. , Dawson H. , Jenkins K. , Kay D. W. K.
Published: August 2003

Background The Prudhoe Cognitive Function Test (PCFT) was designed to measure cognitive function in subjects with all degrees of intellectual disability (ID) and to be administered by non‐specialist raters. The aim of the present study was to measure the test–retest and inter‐rater reliability of the PCFT.

Methods Three raters, one a specialist and two non‐specialists, administered the PCFT to 14 subjects with Down's syndrome on two occasions separated by 4 weeks.

Results The intra‐class correlation coefficients (ICCs) between the rater pairs (n = 3) were 0.99, 0.99 and 0.98 (P < 0.01). Floor effects were recorded for two items. The ICC for test–retest reliability was 0.99 (P < 0.01).

Conclusions The PCFT is a highly reliable instrument when used by either specialist or non‐specialist raters. It has excellent temporal stability.
Impulsiveness as a factor in sexual offending by people with mild intellectual disability
Authors: Parry C. J. , Lindsay W. R.
Published: August 2003

Background  It has been suggested that sexual offending by people with intellectual disability (ID) results from a pattern of impulsive behaviour that is consistent with psychosocial disadvantage, rather than sexual deviancy. This study aimed to explore this hypothesis by assessing levels of impulsiveness in sexual offenders, non‐sexual offenders and non‐offenders with mild ID.

Method  Impulsiveness was assessed using a modified version of the Barratt Impulsiveness Scale (11th edition). Total impulsivity scores were compared between sexual offenders, non‐sexual offenders and non‐offenders, all with mild ID.

Results  There was a significant difference in the levels of impulsiveness between sexual offenders and non‐sexual offenders with ID (t = 2.83, P < 0.01). The sexual offenders were less impulsive than non‐sexual offenders.

Conclusions  This study did not support the hypothesis that sexual offending by people with ID is better explained by impulsive behaviour rather than sexual deviancy. It supports recent findings that among the general population, sexual offenders are less impulsive than controls and violent offenders.
Development and preliminary evaluation of a questionnaire on cognitions related to sex offending for use with individuals who have mild intellectual disabilities
Authors: Broxholme S. L. , Lindsay W. R.
Published: August 2003

Background  A number of authors note that distorted cognitions may play a significant role in sex offending behaviour in both the people with intellectual disability (ID) and general populations. However, no scales have been specifically developed for use with individuals with ID. To date, there is no valid, reliable, self‐report questionnaire that assesses cognitive factors in these individuals. This paper aims to develop a valid, reliable self‐report questionnaire to assess antisocial attitudes consistent with sex offending behaviour in individuals who have mild ID.

Methods  Seventeen male individuals with ID who had sexually offended were compared with two non‐sex offender groups: 19 males with and 36 males without ID. The Questionnaire on Attitudes Consistent with Sex Offending (QACSO) measure was used to establish sexual attitudes in the three groups. The reliability and validity of the QACSO was examined.

Results  The groups were compared and results demonstrated that the QACSO is a promising tool in terms of providing an internally consistent, reliable and valid indicator of cognitive distortions/attitudes held by sex offenders with ID.

Conclusions  The limitations, suggestions for modification, potential uses of the questionnaire and directions for further research are proposed.
Psychotropic drug use among people with intellectual disability before and after deinstitutionalization
Authors: Nøttestad J. Aa. , Linaker O. M.
Published: August 2003

Background  The use of psychotropic medication among people with intellectual disability (ID) is widespread, and they are one of the most medicated groups in society. A substantial number of individuals with ID receive psychotropic medications that may be inappropriate for their diagnosis. One of the main reasons for the use of psychotropic medication is challenging behaviours. Almost all prevalence studies show higher prevalence rates of psychotropic medication in institutions compared with community living. Studies on deinstitutionalization and the use of psychotropic medication are few and inconclusive.

Method  The present study is a prospective cohort study without control group. It examines the use of psychotropic medication among 109 subjects aged between 16 and 65 years before (1987) and after (1995) deinstitutionalization. Psychotropic drug dosages were transformed to percentage of defined daily dosage.

Results  We found no major changes in the use of neuroleptics after deinstitutionalization neither in frequency nor in dosages, and the trend seemed indiscriminate in relation to diagnosis. The people with schizophrenia or an anxiety disorder did not receive proper drug treatment, nor did they before deinstitutionalization.

Conclusions  The main predictor variable for neuroleptic dosage both before and after deinstitutionalization was challenging behaviour. The reason for this may be the difficulties in determining the extent to which presenting behaviours are the result of a psychiatric disorder or a behaviour disorder, the lack of knowledge among the caretakers and the ensuing referral practice, the lack of knowledge among the general practitioners, and the lack of access to specialized health services.
Carers’ expressed emotion, appraisal of behavioural problems and stress in children attending schools for learning disabilities
Authors: Lam D. , Giles A. , Lavander A.
Published: August 2003

Background  Expressed emotion (EE) has been found to be high in families with children suffering from conduct disorder as well as a variety of childhood psychiatric disorders. Expressed emotion has been associated with high levels of stress in carers. However, behavioural problems in children do not automatically lead to stress in carers. Carers’ beliefs and behaviour could affect how they appraise and cope with their child's behaviour. Furthermore, the perceived adequacy of social support can also be an important factor in determining the family's level of stress. The study investigates the relationship between EE variables and carers’ appraisal and coping with the child's behaviour, stress and social support.

Methods  Forty‐seven carers were recruited from schools for moderate to severe learning disabilities. Carers filled in questionnaires and took part in the Camberwell Family Interview for EE status. Carers’ EE status was determined by a rater blind to the carers’ questionnaires scores.

Results  There was no difference between high and low EE groups in the descriptive information of the child's independence, communication skills, or the frequency of behavioural problems. However, high EE carers appraised more of their children's behaviour as definite problems and their available social support to be less adequate. High warmth was found to relate to more positive reappraisal and less escape‐avoidance coping. A multiple regression analysis indicated that carers’ EE, psychological well‐being, appraisal of their children's behaviour, their children's communication skills and respite usage predicted 62% of the variance in their perceived stress scores.

Conclusion  It is important to consider optimal use of respite care and psychosocial intervention to encourage positive appraisal and problem solving.
Caregiving burden of families looking after persons with intellectual disability and behavioural or psychiatric problems
Authors: Maes B. , Broekman T. G. , Došen A. , Nauts J.
Published: August 2003

Background  During the last decade, there has been a growing interest in outpatient support services for persons with intellectual disability (ID) and psychiatric and/or behavioural problems and their families. In this study, we explore the family burden that is associated with children or adults with ID and behavioural or psychiatric problems living at home.

Method  The research group consisted of 66 clients of In Casa, a project of outpatient treatment. Their average age is 18.97 years and their average IQ 55.37. The Reiss Screen for Maladaptive Behaviour (adults) or Reiss Scales for Children's Dual Diagnosis (children) and the Nijmegen Family Situation Questionnaire have been administered.

Results  About 62% of the children and 86% of the adults living at home and referred to In Casa have severe psychiatric or behavioural problems as measured by the Reiss scales. The dual diagnosis has a more negative impact on the family situation than the condition of ID only.

Conclusion  Parents consider the psychiatric or behavioural problems of their child to be an extra burden and feel it more difficult to raise and manage such a child. This impels them to change the situation and to call on the help of external services. Some methodological questions and the implications of the findings in terms of support needs are discussed.
Referral trends of people with intellectual disabilities and psychiatric disorders
Authors: Bouras N. , Cowley A. , Holt G. , Newton J. T. , Sturmey P.
Published: August 2003

Background  The Specialist Mental Health Service for people with an intellectual disability (ID) and psychiatric disorder (referred to throughout this paper as ‘the Service’) has been in operation in south‐east London for the last 18 years, during which time two local, long‐stay institutions have closed.

Aims  To measure the number of referrals to the Service from 1983 to 2001 and identify trends.

Methods  Data were recorded on 752 new referrals using the assessment and information rating profile. Diagnoses according to the International Classification of Diseases (10th edition) were made by two psychiatrists. Referrals for a one off consultation or assessment, or with an IQ > 70 were excluded from analysis.

Results  Over time more non‐white clients and more clients with mild ID were referred. More referrals were made in later years, and a greater proportion came from primary care. Later referrals were also more likely to have a psychiatric diagnosis than those in earlier years.

Conclusion  Significant trends in referrals were identified, which may be explained by various external factors.
Rituals and compulsivity in Prader–Willi syndrome: profile and stability
Authors: Wigren M. , Hansen S.
Published: August 2003

Background  Prader–Willi syndrome (PWS) is characterized by an increased risk for obsessive–compulsive disorder. This study investigated the nature of compulsive‐like behaviours in the PWS.

Method  Parents of 50 individuals with PWS (aged 5–18 years) and 50 typically developing 4‐year‐old children completed the Childhood Routines Inventory. This instrument measures compulsive‐like behaviours in normative childhood.

Results  Many childhood compulsive behaviours are prevalent among older children and adolescents with PWS. Group differences were observed in that the PWS group, independent of age, gender and cognitive dysfunctions, exhibited more intense compulsive behaviours related to insistence on sameness in many daily activities and social contexts. Findings also revealed an age‐independent low‐prevalent pattern of PWS compulsivity, probably related to other features in the PWS symptomatology.

Conclusions  Compulsions of childhood do not subside with age in adolescents with PWS. The findings indicate that the differentiation between delayed childhood rituals and pathological manifestations of compulsive features is complex in PWS populations.
Depressive symptoms in intellectual disability: does gender play a role?
Authors: Lunsky Y.
Published: August 2003

Background  Gender issues remain largely unaddressed in the dual diagnosis arena, even in the area of depression where there is a 2 : 1 female to male ratio in the general population. This paper argues that women with intellectual disability (ID) report higher levels of depressive symptoms than men with ID and that risk factors for depression identified for women in the general population are relevant to this group.

Method  Findings are based on structured interviews with 99 men and women with ID, with corroborative information provided from caregivers and casebook reviews.

Results  Overall, women reported higher levels of depression than men. Individuals with higher depression scores were more lonely and had higher stress levels than individuals with lower scores. Women with higher depression scores were more likely to report coming from abusive situations, to have poor social support from family and to be unemployed when compared to women with lower scores, but similar differences were not found when comparing men with higher and lower depression scores.

Conclusion  Men and women who report experiencing these psychosocial correlates of depression should be a target group for future prevention efforts, taking gender specific concerns into consideration.
Risk markers associated with challenging behaviours in people with intellectual disabilities: a meta‐analytic study
Authors: McClintock K. , Hall S. , Oliver C.
Published: August 2003

A meta‐analysis of prevalence and cohort studies conducted over the last 30 years was carried out to identify risk markers for challenging behaviour shown by individuals with intellectual disabilities (IDs). A total of 86 potential studies was identified from the review, with 22 (25.6%) containing sufficient data to enable a statistical analysis to be conducted. Results indicated that males were significantly more likely to show aggression than females, and that individuals with a severe/profound degree of ID were significantly more likely to show self‐injury and stereotypy than individuals with a mild/moderate degree of ID. Individuals with a diagnosis of autism were significantly more likely to show self‐injury, aggression and disruption to the environment whilst individuals with deficits in receptive and expressive communication were significantly more likely to show self‐injury. In most cases, tests for heterogeneity were statistically significant, as expected. The meta‐analysis highlighted the paucity of methodologically robust studies of risk markers for challenging behaviours and the lack of data on incidence, prevalence and chronicity of challenging behaviour in this population.
Zosteriform connective tissue nevus: a case report
Authors: Yeh Shih Wei , Magalhaes Aline Maria , Vasconcellos Monica R. A. , Michalany Nilceo S. , Tomimori Yamashita Jane
Published: September 2003

Because of its distinctive clinical features and histopathological characteristics, zosteriform connective tissue nevus is considered a separate entity from other connective tissue nevi. Only two cases have previously been reported in the worldwide dermatological literature. Here we report a zosteriform connective tissue nevus in a 3‐year‐old boy with similar clinical presentation.
The prevalence of pediculosis capitis in schoolchildren in Mersin, Turkey
Authors: Kokturk Aysin , Baz Kiymet , Bugdayci Resul , Sasmaz Tayyar , Tursen Umit , Kaya Tamer Irfan , Ikizoglu Guliz
Published: September 2003

Background  Pediculosis capitis is an endemic parasitosis affecting many countries of the world. The aim of this study was to investigate the incidence of head lice infestation in Mersin, Turkey.

Methods  A total of 5318 elementary schoolchildren, aged 8–16 years, were examined for the presence of Pediculus capitis. If any evidence of head lice was detected, such as live or dead eggs, or nits, the child was considered to be infected. The following details were recorded for each child: age, sex, family size, monthly income, number of siblings, parents’ education, presence or absence of social security of the family, pet (cat or dog) ownership, and frequency of hair washing (per week). The chi‐squared test and logistic regression analysis were performed to analyze the results.

Results  Pediculosis capitis was detected in 360 (6.8%) children. The prevalence of infestation was significantly higher in girls (13.3%) than in boys (1.1%) (χ2 = 313.2, d.f. = 1, P = 0.000). Children aged 8–9 years exhibited a significantly lower prevalence rate than those aged 10–11 years and those aged 12 years and above. The following variables were found to be statistically significantly related to pediculosis capitis: sex, age, father's education level, and pet ownership (cat or dog).

Conclusions  Our results show that the prevalence of pediculosis capitis is not very high in Mersin, Turkey, and is observed in all schools regardless of the socio‐economic and personal hygiene status of the children.
Context‐related representation of timing processes in monkey motor cortex
Authors: Roux Sébastien , Coulmance Michèle , Riehle Alexa
Published: August 2003

Precise timing is essential for motor performance, though the neuronal representation of time is unknown. To explore neuronal correlates of timing processes during movement preparation and execution, we compared the activities of neurons recorded in monkey motor cortex during the performance of two tasks requiring correct time estimation in different contextual situations. Despite the fact that both tasks had many common features (e.g. same movements, same time intervals to estimate), they involved different degrees of spatial and temporal uncertainty. Our findings indicate that time is indeed represented in neuronal activity of the motor cortex, albeit strongly dependent on context and not in an invariant manner as a distinct process per se.
The effect of 6‐hydroxydopamine lesions on the release of amino acids in the direct and indirect pathways of the basal ganglia: a dual microdialysis probe analysis
Authors: Bianchi L. , Galeffi F. , Bolam J. P. , Della Corte L.
Published: August 2003

The loss of dopaminergic neurons of the substantia nigra in Parkinson's disease and in animal models of Parkinson's disease is associated with an imbalance in the activity of the so‐called ‘direct’ and ‘indirect’ pathways of information flow through the basal ganglia. The aim of the present study was to determine whether the imbalance is reflected in changes in the release of GABA, aspartate and glutamate in the pathways using dual probe microdialysis in freely moving rats. Control and 6‐hydroxydopamine‐(6‐OHDA)‐lesioned rats were implanted with microdialysis probes in the neostriatum and substantia nigra or globus pallidus and the release of amino acids was analysed in the dialysates. Basal levels of amino acids were largely unaltered by the 6‐OHDA lesion; however, the levels of GABA in the globus pallidus dialysates were significantly elevated in the lesioned rats, indicating an imbalance in favour of the indirect pathway. Administration of kainic acid to the neostriatum enhanced the release of GABA locally and in the distal probes in the substantia nigra and globus pallidus. In 6‐OHDA‐lesioned rats, stimulated release of GABA in the substantia nigra was abolished, indicating a reduction in transmission along the direct pathway. Thus, consistent with the direct–indirect pathway model of the basal ganglia, the 6‐OHDA lesion results in an elevation of the basal release of GABA in the striatopallidal (indirect) pathway and a reduction in the evoked release of GABA in the striatonigral (direct) pathway. These imbalances may underlie, at least in part, the motor abnormalities of Parkinson's disease and in animal models of Parkinson's disease.
Passage of progesterone into the brain changes with photoperiod in the ewe
Authors: Thiéry J. C. , Robel P. , Canepa S. , Delaleu B. , Gayrard V. , Picard‐Hagen N. , Malpaux B.
Published: August 2003

In this study we tested the hypothesis that photoperiod can modulate steroid access to the brain in a seasonal breeder. To this goal, we compared the passage of exogenous progesterone to the brain of female sheep maintained under short (SD) or long (LD) daylengths. In the first experiment, we studied two groups of ovariectomized females maintained under SD or LD, for three artificial cycles, consisting of bearing a subcutaneous oestradiol implant (E2‐treated) and an intravaginal device releasing progesterone (CIDR). During the third cycle, the concentrations of progesterone and of its metabolites 5α‐dihydroprogesterone and 3α‐hydroxy‐5α‐pregnan‐20‐one were measured in the preoptic area (POA). The levels of progesterone in the POA were higher in ewes under LD than under SD while the amounts of metabolites were unchanged. In the second experiment, we compared ovariectomized female sheep equipped with a cannula in the third ventricle to sample the cerebrospinal fluid (CSF) under LD vs. SD. After progesterone (1 mg and 10 mg) was injected into the carotid artery, it was only detectable in the cerebrospinal fluid in sheep under LD. In the third experiment, we compared progesterone concentration in plasma and CSF in two groups of SD vs. LD ovariectomized E2‐treated ewes for 2 h under CIDR treatment. Despite similar progesterone plasma concentrations, concentration in the CSF was 2.5 times higher in SD than in LD. Our results suggest a physiological modulation of the passage of progesterone to the brain according to the photoperiod.
Intracerebroventricular administration of an endothelin ETB receptor agonist increases expressions of GDNF and BDNF in rat brain
Authors: Koyama Yutaka , Tsujikawa Kimiko , Matsuda Toshio , Baba Akemichi
Published: August 2003

Endothelins (ETs) are suggested to be involved in functional alterations of astrocytes after brain injury, including proliferation, hypertrophy and production of neurotrophic factors. In this study, effects of Ala1,3,11,15‐endothelin‐1 (Ala1,3,11,15‐ET‐1), an ETB receptor selective agonist, on neurotrophic factor production were examined in rat brain. A continuous intracerebroventricular administration of Ala1,3,11,15‐ET‐1 (500 pmol/day for 7 days) increased the numbers of GFAP‐ and vimentin‐positive astrocytes in the hippocampus, caudate putamen and cerebrum. Ala1,3,11,15‐ET‐1 did not induce neuronal degeneration and activation of microglia/macrophage in these brain regions. The intracerebroventricular administration of Ala1,3,11,15‐ET‐1 for 7 days caused two‐ to three‐fold increases in glial cell line‐derived neurotrophic factors (GDNF) mRNA in the hippocampus and cerebrum. The mRNA levels of brain‐derived neurotrophic factors (BDNF) in caudate putamen were increased by Ala1,3,11,15‐ET‐1. Expressions of nerve growth factor (NGF) and basic fibroblast growth factor (bFGF) mRNA in these regions were not largely affected by Ala1,3,11,15‐ET‐1, except cerebral NGF mRNA level was increased. The Ala1,3,11,15‐ET‐1‐induced increases in GDNF and BDNF mRNA levels were accompanied by increases in immunoreactive GDNF and BDNF. Immunohistochemical observations showed that GFAP‐positive astrocytes expressed GDNF and BDNF in the brain regions of Ala1,3,11,15‐ET‐1‐infused rats. In cultured rat astrocytes, Ala1,3,11,15‐ET‐1 (100 nm) increased mRNA levels of GDNF and BDNF. These results suggest that activation of brain ETB receptors induced GDNF and BDNF expression in astrocytes.
A receptor for presynaptic glutamatergic autoinhibition is a glutamate transporter
Authors: Dudel Josef , Schramm Marion
Published: August 2003

Monoquantal excitatory postsynaptic currents were recorded by means of a perfused macropatch electrode from 9 to 15 µm stretches of crayfish neuromuscular junctions. The excitatory transmitter l‐glutamate superfused to a terminal inhibits quantal release by activating autoreceptors [Parnas et al. (1996) Eur. J. Neurosci., 8, 116–126]. Substances related to glutamate that do not activate glutamatergic postsynaptic channels, but are substrates of glutamate transporters, elicited analogous inhibitions, e.g. l‐ and d‐aspartate and some other glutamate transport blockers. As expected, all transport blockers prolonged synaptic currents. Blockers that bind to the transporter receptors but are not transported did not inhibit release, but prevented inhibition by the transport substrates. It appears that autoinhibition is elicited by transport of glutamate or its analogues. Transport into cells is powered by symport of three Na+. To block the transport step electrochemically, extracellular Na+ concentration was lowered to one‐quarter, but this surprisingly left the inhibition of release by glutamate unaffected, showing inhibition to be associated to a step between binding and transport. After binding a substrate, glutamate transporters open a parallel Cl− channel. Replacement of extracellular Cl− prevented Cl− current, and release inhibition by glutamate or aspartate was blocked. It is suggested that the flow of Cl− across the cell membrane, after binding a transport substrate, mediates autoinhibition. We measured a related reduction of presynaptic action potentials.
Differential participation of actin‐ and tubulin‐based vesicle transport systems during secretion in bovine chromaffin cells
Authors: Ñeco Patricia , Giner Daniel , Del Mar Francés María , Viniegra. Salvador , Gutiérrez Luis M.
Published: August 2003

The role of cytoskeletal elements in vesicle transport occurring during exocytosis was examined in adrenal medullary bovine chromaffin cells maintained in culture. Amperometric determination of depolarization‐dependent catecholamine release from individual intact cells treated with actin or myosin inhibitors showed alterations in the fast and slow phases of secretion when compared with untreated cells. In contrast, microtubule disassemblers or stabilizers have a moderate effect on secretion, only affecting the release of slow secretory components. In experiments using confocal dynamic microscopy we have observed the drastic effect of actin and myosin inhibitors in abolishing vesicle movement throughout the cytoplasm, and the inhibition of granule mobility in deep perinuclear regions caused by the microtubule stabilizers. Following loss of mobility, vesicles were associated with filaments of F‐actin or microtubules. In addition, the mobility of cortical vesicles was affected by actin–myosin inhibitors but not by microtubule inhibitors. The study of cortical cytoskeleton in living cells showed vesicles associated with dense tubular F‐actin structures, with microtubules appearing as low density networks. These findings suggest that the distribution and density of both cytoskeletal elements in the cortical region may influence the recruitment of vesicle pools during secretion.
High frequency stimulation of the subthalamic nucleus has beneficial antiparkinsonian effects on motor functions in rats, but less efficiency in a choice reaction time task
Authors: Darbaky Yassine , Forni Claude , Amalric Marianne , Baunez Christelle
Published: August 2003

Chronic subthalamic nucleus high frequency stimulation (STN HFS) improves motor function in Parkinson's disease. However, its efficacy on cognitive function and the mechanisms involved are less known. The aim of this study was to assess the effects of STN HFS in hemiparkinsonian awake rats performing different specific motor tests and a cognitive operant task. Unilateral STN HFS applied in unilaterally DA‐depleted rats decreased the apomorphine‐induced circling behaviour and reduced catalepsy induced by the neuroleptic haloperidol. DA‐depleted rats exhibited severe deficits in the operant task, among which the inability to perform the task was not alleviated by STN HFS. However, in a few animals showing less impairment, STN HFS significantly reduced the contralateral neglect induced by the lesion. These results are the first to demonstrate a beneficial effect of STN HFS applied in awake rats on basic motor functions. However, STN HFS appears to be less effective on impaired cognitive functions.
Adult neural progenitor cell grafts survive after acute spinal cord injury and integrate along axonal pathways
Authors: Vroemen Maurice , Aigner Ludwig , Winkler Juergen , Weidner Norbert
Published: August 2003

The main rationale for cell‐based therapies following spinal cord injury are: (i) replacement of degenerated spinal cord parenchyma by an axon growth supporting scaffold; (ii) remyelination of regenerating axons; and (iii), local delivery of growth promoting molecules. A potential source to meet these requirements is adult neural progenitor cells, which were examined in the present study. Fibroblast growth factor 2‐responsive adult spinal cord‐derived syngenic neural progenitor cells were either genetically modified in vitro to express green fluorescent protein (GFP) using retroviral vectors or prelabelled with bromodeoxyuridine (BrdU). Neural progenitor cells revealed antigenic properties of neurons and glial cells in vitro confirming their multipotency. This differentiation pattern was unaffected by retroviral transduction. GFP‐expressing or BrdU‐prelabelled neural progenitor cells were grafted as neurospheres directly into the acutely injured rat cervical spinal cord. Animals with lesions only served as controls. Three weeks postoperatively, grafted neural progenitor cells integrated along axonal profiles surrounding the lesion site. In contrast to observations in culture, grafted neural progenitor cells differentiated only into astro‐ and oligodendroglial lineages, supporting the notion that the adult spinal cord provides molecular cues for glial, but not for neuronal, differentiation. This study demonstrates that adult neural progenitor cells will survive after transplantation into the acutely injured spinal cord. The observed oligodendroglial and astroglial differentiation and integration along axonal pathways represent important prerequisites for potential remyelination and support of axonal regrowth.