bluuebunny/crossref_metadata_2025_split huggingface dataset:
Midsummer spatial variation in methane efflux from stands of littoral vegetation in a boreal meso‐eutrophic lake
Authors: Kankaala Paula , Mäkelä Suvi , Bergström Irina , Huitu Eeva , Käki Tiina , Ojala Anne , Rantakari Miitta , Kortelainen Pirkko , Arvola Lauri 
Published: August 2003

Summary1. Spatial variation of methane (CH4) efflux from the littoral zone of a meso‐eutrophic boreal lake was studied with a closed‐chamber technique for three summer days in 22 vegetation stands, consisting of three emergent and three floating‐leaved species.2. Between‐species differences in CH4 emission were significant. The highest emissions were measured from the emergent Phragmites australis stands (0.5–1.7 mmol m−2 h−1), followed by Schoenoplectus lacustris > Equisetum fluviatile > Nuphar lutea > Sparganium gramineum > Potamogeton natans. Within‐species differences between stands were not significant.3. In P. australis stands, the stand‐specific mean CH4 emission was significantly correlated with solar radiation, probably indicating the role of effective pressurised ventilation on CH4 fluxes. The proportion of net primary production emitted as CH4 was significantly higher in P. australis stands (7.4%) than in stands of S. lacustris and E. fluviatile (both 0.5%).4. In N. lutea stands, CH4 efflux was negatively correlated with the mean fetch and positively with the percentage cover of leaves on the water surface. There were no differences in CH4 efflux between intact N. lutea leaves and those grazed by coleopteran Galerucella nymphaeae. In S. graminaeum and P. natans stands, CH4 effluxes were not related to any of the measured environmental variables.5. For all vegetation stands, the biomass above water level explained about 60% of the observed spatial variation in CH4 emission, indicating the important role of plants as gas conduits and producers of substrates for methanogens in the anoxic sediment.
Substratum stability associated with the riverine macrophyte Justicia americana
Authors: Fritz Ken M. , Feminella Jack W. 
Published: August 2003

Summary1. Patches of stable substratum in streams may be important refugia for benthic organisms during scouring floods. Streambed stone stability, packing and embeddedness were assessed within and adjacent to beds of the macrophyte Justicia americana in five Alabama streams.2. The force needed to dislodge stones and embeddedness was about two times lower outside Justicia beds than within them. Significant positive correlations between stone stability and (i) degree of embeddedness, and (ii) the abundance of binding rhizomes and the presence of attached roots indicate that Justicia may physically modify the local streambed, indirectly enhancing substratum stability and reducing flow, thereby increasing sand deposition.3. Despite higher stability (i.e. physical refugia during bed‐moving spates) within Justicia beds, the abundance of epilithic plants (moss and Podostemum ceratophyllum) and pleurocerid snails (Elimia spp.) was similar both inside and outside the macrophyte beds. Several physical characteristics within macrophyte beds, such as low light, reduced current and increased sand intrusion, may create suboptimal conditions for benthic organisms in these habitats.4. Additional work is needed to determine if Justicia biogenically enhances substratum stability or if its presence merely reflects patches of stable substratum within the streambed. Regardless of the mechanism, there is an association between Justicia beds and streambed characteristics.
Six years of submerged plant community dynamics in a freshwater tidal wetland
Authors: Capers Robert S. 
Published: August 2003

Summary1. The dynamics of a submerged plant community were studied for 6 years in a freshwater tidal wetland. The degree and nature of change at several spatial scales (quadrat, transect and overall community) was determined, and the implications for community stability were assessed.2. A high degree of change was recorded in 1 m2 quadrats, and this was reflected in 10 m2 transects as well. In quadrats, mean species richness changed every year. Species richness changed in >60% of quadrats each year. Stem number changed by as many as several 100 stems per quadrat from one year to the next.3. Richness varied more among quadrats than among transects and varied less at the community level than among either quadrats or transects. Greater stability at the spatial scale of the whole community was reflected in high scores on the Jaccard and Morasita–Horn indices and Kendall's coefficient of concordance.4. Although most of the submerged species were perennials, persistence at the local scale was low, and 4‐year persistence exceeded 50% for only one species. Change in abundance was largely independent among the species.5. In the face of great small‐scale changes, species remain in the community (and the community persists) because of high recruitment rates.
The concepts of ‘plant functional types’ and ‘functional diversity’ in lake phytoplankton – a new understanding of phytoplankton ecology?
Authors: Weithoff Guntram 
Published: August 2003

Summary1. This is a discussion of the applicability to the phytoplankton of the concepts of ‘plant functional types’ (PFTs) and ‘functional diversity’ (FD), which originated in terrestrial plant ecology.2. Functional traits driving the performance of phytoplankton species reflect important processes such as growth, sedimentation, grazing losses and nutrient acquisition.3. This paper presents an objective, mathematical way of assigning PFTs and measuring FD. Ecologists can use this new approach to investigate general hypotheses [e.g. the intermediate disturbance hypothesis (IDH), the insurance hypothesis and synchronicity phenomena] as, for example, in its original formulation the IDH makes its predictions based on FD rather than species diversity.
A comparative study of the dispersal of 10 species of stream invertebrates
Authors: Elliott J. M. 
Published: August 2003

Summary1. Apart from downstream dispersal through invertebrate drift, few quantitative data are available to model the dispersal of stream invertebrates, i.e. the outward spreading of animals from their point of origin or release. The present study provides comparative data for 10 species, using two independent methods: unmarked animals in six stream channels built over a stony stream and marked animals in the natural stream. Experiments were performed in April and June 1973 and 1974, with initial numbers of each species varying from 20 to 80 in the stream channels and 20 to 60 for marked animals.2. Results were the same for marked invertebrates and those in the channels. Dispersal was not density‐dependent; the number of dispersing animals was a constant proportion of the initial number for each species. The relationship between upstream or downstream dispersal distance and the number of animals travelling that distance was well described by an inverse power function for all species (exponential and log models were poorer fits). Results varied between species but were similar within species for the 4 months, and therefore were unaffected by variations in mean water velocity (range 0.04–0.35 m s−1) or water temperature (range 6.7–8.9 °C in April, 12.1–14.8 °C in June).3. Species were arranged in order, according to their dispersal abilities. Three carnivores (Perlodes, Rhyacophila, Isoperla) dispersed most rapidly (70–91% in 24 h, maximum distances 9.5–13.5 m per day), followed by two species (Protonemura, Rhithrogena) in which about half their initial numbers dispersed (50–51% in 24 h, 7.5–8 m per day), and four species (Ecdyonurus, Hydropsyche, Gammarus, Baetis) in which less than half dispersed (33–40% in 24 h, 5.5–7 m per day). Dispersal was predominantly upstream for all nine species. Few larvae (20%) of Potamophylax dispersed, with similar maximum upstream and downstream distances of 3.5 m per day. The mean time spent drifting downstream was known for seven species from previous studies, and correlated positively with their dispersal distances. Therefore, the species formed a continuum from rapid to very slow dispersers. These interspecific differences should be considered when evaluating the role of dispersal in the maintenance of genetic diversity in stream invertebrates, and in their ability to colonise or re‐colonise habitats.
Orientation and training of preclinical medical students in the use of the library*
Authors: STRICKLAND‐HODGE B. 
Published: August 2003

The importance of library instruction for medical students is emphasized. Previous work is discussed and brief descriptions of programmes and methods used in the USA and New Zealand are described.Research has recently been carried out into British practice, specifically with regard to library orientation and training for preclinical medical students. Librarians were canvassed for their opinions using a postal questionnaire Interviews were also carried out, with teaching staff and medical students. Results indicate that no standard approach is possible and a variety of techniques are helpful. It is concluded that orientation of students is vital, but should be short, conducted with small groups and initially should concentrate on basic information only. Additional training should only be carried out in cases of speciJic need, for example completion of a tutor set project.
The relationship between dental aesthetic index (DAI) and perceptions of aesthetics, function and speech amongst secondary school children in Ibadan, Nigeria
Authors: Onyeaso C. O. , Aderinokun G. A. 
Published: August 2003

Summary.Objective. The purpose of the study was to investigate the relationship between a professionally derived index, the Dental Aesthetic Index, and some indications for orthodontic treatment as perceived by potential patients.Methods. An epidemiological survey of 614 secondary school students, 327 males (53·3%) and 287 females (46·7%) was carried out in Ibadan, Nigeria. Children aged 12–18 years (mean age, 14·9 ± 2·9 SD) were randomly selected, none of them had received previous orthodontic treatment. One examiner assessed the students using the Dental Aesthetic Index (DAI). Subjects were also asked to complete a questionnaire consisting of three questions concerning appearance, function, and speech, using a 5‐point Likert scale.Results. Weak but statistically significant correlations were found for subjective assessments of appearance of teeth and the DAI (r = 0·174; P < 0·01) and between biting/chewing and appearance of teeth (r = 0·095; P < 0·05). Statistically significant correlations were found between appearance of teeth and speech (r = 0·148; P < 0·01) and biting/chewing and speech. The last showed the strongest correlation (r = 0·268; P < 0·01).Conclusion. The study has shown weak but significant correlation between DAI and children's perceptions of the appearance of their teeth. We recommend further study involving both DAI and Index of Orthodontic Treatment Need (IOTN) for comparison in the Nigerian population.
Relative analgesia and general dental practitioners: attitudes and intentions to provide conscious sedation for paediatric dental extractions
Authors: Freeman R. , Carson P. 
Published: August 2003

Summary.Aim. To examine the attitudes and intentions of general dental practitioners (GDPs) who work within the remit of the National Health Service (NHS) to provide relative analgesia (RA) for paediatric extractions.Methods. All 45 GDPs working within the boundaries of one Trust were asked to complete a questionnaire to assess demography, etc., intention and attitudes to provide RA for paediatric extractions.Results. Ninety‐eight per cent of GDPs took part. All GDPs worked within the NHS. Twenty‐nine per cent of GDPs stated that they had RA equipment available in their practices and 68% stated that they discussed RA as treatment alternative. Eighty‐seven per cent referred their paediatric extraction cases for dental general anaesthesia. The behavioural intention was predicted by total attitude score and the availability of RA equipment in the practice (R2 = 0·97, F(37,5) = 260·11, P < 0·001). Total attitude was predicted by clinical competency, few financial worries or time concerns and the availability of RA equipment (R2 = 0·91, F(38,4) = 106·21, P < 0·001).Conclusions. This study suggests that GDPs’ concerns of clinical competence and costs have an inhibiting effect upon their intention to provide RA for paediatric extractions. These concerns must be addressed by planners and policy makers if there is to be a shift from hospital‐based DGA to surgery‐based RA services for paediatric extractions.
Cutaneous horn occurring on the lip of a child
Authors: Souza L. N. , Martins C. R. , De Paula A. M. B. 
Published: August 2003

Summary.Cutaneous horn is a relatively uncommon lesion consisting of keratotic material resembling that of an animal horn. This kind of lesion is more common in Caucasians and in older age groups. The primary lesion underlying the horny material may be benign, premalignant or malignant. The treatment of choice is an excisional biopsy with a narrow margin, because of the possibility of malignancy. The material must be submitted for histopathological evaluation. The first reported case of cutaneous horn arising on the vermillion border of the lower lip in a black child is presented.
Treatment outcome in subgroups of uncooperative child dental patients: an exploratory study
Authors: Arnrup K. , Broberg A. G. , Berggren U. , Bodin L. 
Published: August 2003

Summary.Objectives.The principal aims of this study were to evaluate the treatment outcome in subgroups of uncooperative child dental patients and to test the validity of these subgroups, which were based on fear and personality characteristics.Design.An exploratory, intervention study using quantified questionnaire, interview and observation data.Sample and methods.Eighty‐six 4 to 12‐year‐old uncooperative child dental patients (of whom 81 were divided retrospectively into four subgroups) and their accompanying parents were followed up during treatment at a specialist paediatric dental clinic in Sweden. Treatment was based on behaviour management techniques, supported by nitrous oxide/oxygen sedation if necessary. At baseline, parents answered a questionnaire including questions on child dental and general fear, temperament and behaviour, and parental dental fear, emotional stress, locus of control, parenting efficacy and attitudes to dental care, some of which were repeated post‐treatment. The treating dentist rated child behaviour according to the acceptance of a maximum of 14 treatment steps at each visit.Results.Approximately 90% of all children managed to undergo the dental treatment. Child dental fear and parental emotional stress decreased during treatment. Externalizing, impulsive children showed lower acceptance. In fearful, inhibited children, integrated use of sedation appeared to facilitate acceptance. Validity of the subgroups characterized as ‘fearful, extrovert, outgoing’, ‘fearful, inhibited’ and ‘externalizing, impulsive’ was supported, while heterogeneity within the group of ‘non‐fearful, extrovert, outgoing’ children made validation difficult.Conclusion.Fear and personality characteristics may serve as diagnostic aids when planning treatment of uncooperative child dental patients. Controlled outcome studies using differentiated treatment methods for children with different fear and personality profiles are needed.
Premature exfoliation of primary molars related to the use of formocresol in a multivisit pulpotomy technique: a case report
Authors: Hunter M. L. 
Published: August 2003

Summary.Since its introduction in 1904, formocresol has become one of the most widely studied dental medicaments. In the United Kingdom, it is the preferred primary tooth pulpotomy medicament of the majority of Specialists in Paediatric Dentistry [1]. Reports of adverse effects resulting from its clinical use are rare. This paper presents a case of premature exfoliation of primary molars that may be related to the use of formocresol in a multivisit pulpotomy technique.
Unusual manifestations in X‐linked Amelogenesis Imperfecta
Authors: Lykogeorgos T. , Duncan K. , Crawford P. J. M. , Aldred M. J. 
Published: August 2003

Summary.This paper describes a female with X‐linked amelogenesis imperfecta (XAI). This case is unusual in having taurodontism, pulpal calcifications, coronal defects prior to tooth eruption and unerupted teeth. These findings have been reported in some cases of autosomal dominant and autosomal recessive AI but have not previously been documented in XAI.
Children with Down Syndrome: oral development and morphology after use of palatal plates between 6 and 18 months of age
Authors: Bäckman B. , Grevér‐Sjölander A‐C. , Holm A‐K. , Johansson I. 
Published: August 2003

Summary.Objectives. The aim of this study was to describe oral development and morphology in 18‐month‐old children with Down syndrome (DS) treated with palatal plates in combination with structured communication and speech training. The aim is further to describe the design of the palatal plates, compliance in their use and to give a brief report of their effect on oral motor function and speech.Sample and methods. Forty‐two children with DS were followed from ≤ 6 months of age until 18 ± 3 months old. In addition to language intervention, and oral motor and sensory stimulation provided by speech therapists for all children with DS in Sweden, palatal plates provided by dentists are included in the training programme. In the evaluation, the children in the project were compared with two control groups of children matched for age; one group of children with DS who had not been treated with palatal plates, and one group of children with normal development.Results. Compared to the children with normal development, both groups of children with DS had fewer teeth erupted and a lower prevalence of sucking habits. Deviant morphology of the tongue in the form of diastase, lingua plicata or a sulcus in the anterior third of the tongue was only seen in children with DS. All children with normal development had positive values for overjet compared to 53% of the children with DS. The palatal plates were used 2–3 times daily for a total mean time of 15 min. Compliance in use of the plates decreased with age, mainly due to eruption of teeth and subsequent loss of retention. Evaluation of oral motor function and speech show that the children with DS in the project had better motor prerequisites for articulation than the control children with DS.Conclusion. Palatal plate therapy did not affect oral parameters, i.e., eruption of teeth, types and prevalence of sucking habits, tongue morphology and symptoms of hypotonia. In combination with oral motor and sensory stimulation, palatal plate therapy had a positive effect on oral motor performance and prerequisites for articulation.
Perceived information needs in respect of orthodontics amongst 11–12‐year‐old girls: a study through health visitor sessions in schools
Authors: Habibian M. , Gelbier S. , Munday B. A. 
Published: August 2003

Summary.Aim. The aims of this study were: to explore: (i) the knowledge and views regarding orthodontics of a group of 11–12‐year‐old girls attending a school in South‐east London and (ii) the terms that they used to obtain the information.Methods and subjects. The study used Dental Health Education sessions to investigate the aims of the study. Eight DHE sessions at a secondary school for girls were tape recorded. In order to raise the issue of orthodontics and trigger the formation of questions during health education session, a worksheet containing true/false questions, a crossword puzzle regarding orthodontics and some open ended questions was designed and sent to students. They were required to read and complete the worksheet before each session. They were not required to return the completed worksheets to the investigators but did return them to their teachers. The sessions were tape recorded and supplemented by notes taken at the sessions by the investigator. A total of eight DHE sessions, attended by 14 girls each, were tape‐recorded. Each tape recording was immediately transcribed verbatim. The next stage was to organize the data and to single out the orthodontic questions and discussions and categorize them.Results. A total of 117 girls aged 11–12‐year‐old comprised the study group: 77% were white and 23% black children. After reading the transcripts several times, certain themes on orthodontics emerged. The results showed that children questioned different aspects of orthodontics. Nine themes emerged from their questions and discussions. They wanted to know why orthodontic treatment was carried out and when was the right time to start treatment. They were very keen to find out the differences between different orthodontic appliances. The psychosocial impacts of wearing an orthodontic appliance, i.e., experience of pain as well as the need for extraction of some permanent teeth as part of the treatment were of concern. They asked some questions on the need for repair, adjustment and taking care of appliances. The aetiology of malocclusion was another theme that emerged. The students tended to ask questions and describe problems in their own lay terms.Conclusion. The methodology used in this study provided an opportunity to assess the information needs with regards to orthodontics of a group of children attending a school in Southwark, London, UK. It was successful in discovering the views and concerns, and to some extent, their knowledge regarding orthodontics and the terms pupils used in asking questions and making comments.
The progression of tooth erosion in a cohort of adolescents of mixed ethnicity
Authors: Dugmore C. R. , Rock W. P. 
Published: August 2003

Summary.Objectives. To establish the prevalence of tooth erosion in a sample of 12‐year‐old children and to monitor changes over the subsequent 2 years.Methods. A random sample of 1753 children aged 12 years was drawn from all 62 state maintained schools in Leicestershire. A total of 1308 were re‐examined 2 years later. Erosion was recorded on incisors and first molars using an erosion index based upon that from the Children's Dental Health in the United Kingdom 1993 survey. A score was also allocated to each subject according to the most advanced lesion in the mouth.Results. Erosion was present in 56·3% of subjects at age 12 and 64·1% at age 14. Deep enamel or dentine was eroded in 4·9% and 13·1% of subjects, respectively, at the same ages. One hundred and sixty‐one (12·3%) children who were erosion‐free at 12 years of age developed erosion over the subsequent 2 years. Boys had more erosion than girls, as did white compared to Asian children. Associations were found between erosion experience and social deprivation.Conclusion. New erosive lesions developed in 12·3% of the subjects between the ages of 12 and 14 years. New or more advanced lesions were seen in 27% of the children over the 2 years of the study. Males, white children and social deprivation were significantly associated with erosion experience.