bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of potential larval supply, settlement and post‐settlement processes on the distribution of two species of filter‐feeding caddisflies
Authors: SHARPE ANDREW K. , DOWNES BARBARA J. 
Published: March 2006

Summary1. Hydropsychid caddisfly larvae are often abundant in fast flow habitats and on highly textured substrata. Such patterns are usually inferred to result from habitat preference, but the roles of larval supply to the benthos and post‐settlement events are rarely examined for stream populations. We describe a manipulative field experiment that examined larval supply, habitat preference and post‐settlement events simultaneously for two co‐occurring species of hydropsychids.2. Ten artificial channels were constructed in a natural riffle to create fast and slow flow habitats and within each channel we placed six artificial substrata whose surfaces had been modified to create three different texture treatments. We measured discharge through channels and monitored hydropsychid colonisation of substrata every 3–4 days. Half of the substrata had all hydropsychids and nets removed every 3–4 days (short‐term colonisation) whereas the remaining half were counted but nets and hydropsychids left attached (long‐term colonisation). Short‐term counts of nets and individuals were summed to allow comparison with long‐term colonisation substrata.3. Smicrophylax sp. AV2 larvae were more abundant in fast flow channels than slow flow channels, but these differences were proportional to discharge through each of the channels, suggesting that supply of settlers can explain this pattern. Smicrophylax larvae were least abundant on smooth substrata, which suggests that this species selects habitats based on surface texture. Alternatively, Asmicridea sp. AV1 larvae were only found in fast flow channels and this most likely reflects an active habitat choice by this species, but there was no significant difference between different texture treatments.4. There were no differences between summed, short‐ and long‐term counts of recruits for either species, but there were more nets than larvae, especially in slow flow channels, by the end of the experiment, suggesting that larval mortality or re‐dispersal after settlement could be considerable.5. Our results indicate that supply, habitat selection at settlement and post‐settlement processes all contributed variously to the distribution of hydropsychid caddisfly larvae, but that each species was affected differentially by these factors. Larval supply and post‐settlement processes are rarely examined by stream researchers and our results demonstrate these factors deserve much more consideration. Calculating accurate larval supply rates to sites is challenging, but we suggest that such detailed information is necessary if we are to sort out what sets limits to distributions and the underlying population structure of stream invertebrate populations.
Diel interactions between prey behaviour and feeding in an invasive fish, the round goby, in a North American river
Authors: CARMAN STEPHANIE M. , JANSSEN JOHN , JUDE DAVID J. , BERG MARTIN B. 
Published: March 2006

Summary1. We studied the diet of the invasive round goby (Neogobius melanostomus) on a diel basis in the Flint River, a warmwater stream in Michigan, U.S.A. Diet and available prey samples were collected seven times over a 24 h period in four consecutive months. The section of river studied lacked zebra mussels (Dreissena polymorpha), the primary prey of adult round gobies elsewhere in the Great Lakes region.2. Diet changed on a diel basis with hydropsychid caddisfly and chironomid larvae predominating during the day, chironomid pupae dominating in the evening and heptageniid mayflies dominating at night. Simultaneous study of macroinvertebrate drift suggested that caddisfly and chironomid larvae were most likely picked from submerged rocks, chironomid pupae were most likely taken during their emergent ascent and mayflies were either captured from the drift or picked from rocks.3. The Flint River lacks a diverse darter (Family: Percidae) and sculpin (Family: Cottidae) fauna and it appears that the round goby has occupied a generalised darter/sculpin niche. Our results indicate that round gobies have the potential to invade successfully riverine systems, particularly those lacking a diverse benthic fish assemblage.
Predator‐released compounds, ambient temperature and competitive exclusion among differently sized Daphnia species
Authors: VIJVERBERG JACOBUS , VOS MATTHIJS 
Published: March 2006

Summary1. We studied the effects of fish water and temperature on mechanisms of competitive exclusion among two Daphnia species in flow‐through microcosms. The large‐bodied D. pulicaria outcompeted the medium sized D. galeata × hyalina in fish water, but not in the control treatment. Daphnia galeata × hyalina was competitively displaced 36 days earlier at 18 °C than at 12 °C.2. It is likely that the high phosphorus content of fish water increased the nutritional value of detrital seston particles by stimulating bacterial growth. Daphnia pulicaria was presumably better able to use these as food and hence showed a more rapid somatic growth than its competitor. This led to very high density of D. pulicaria in fish water, but not in the controls. The elevated D. pulicaria density coincided with high mortality and reduced fecundity in D. galeata × hyalina, resulting in competitive displacement of the hybrid.3. It is clear that the daphnids competed for a limiting resource, as grazing caused a strong decrease in their seston food concentration. However, interference may also have played a role, as earlier studies have shown larger Daphnia species to be dominant in this respect. The high density of large‐bodied D. pulicaria in fish water may have had an allelopathic effect on the hybrid. Our data are inconclusive with respect to whether the reached seston concentration was below the threshold resource level (R*) of the hybrid, where population growth rate and mortality exactly balance, as it would be set in the absence of interference, or whether interference actually raised the hybrid's R* to a value above this equilibrium particle concentration.4. Our results do clearly show that fish‐released compounds mediated competitive exclusion among zooplankton species and that such displacement occurred at a greatly enhanced rate at an elevated temperature. Fish may thus not only structure zooplankton communities directly through size‐selective predation, but also indirectly through the compounds they release.
Orthodontic movement of two root fractured teeth: a case report
Authors: Healey D. L. , Plunkett D. J. , Chandler N. P. 
Published: March 2006

AbstractAim  To illustrate significant tipping orthodontic movement of root fractured teeth.Summary  As the frequency of root fractured maxillary teeth is related to increased overjet and reduced lip coverage, orthodontic treatment may increase lip coverage and reduce the risk of trauma or its severity. It may also be necessary to move previously traumatized teeth. Two root fractured teeth were tipped through a considerable angle (19°) to reduce a large overjet and followed up for 5 years.Key learning points •Reduction of large overjets involving root fractured teeth may not affect pulp vitality.•Root fragment separation prior to orthodontics did not appear to increase in this patient, but angulation of the fragments did not completely follow the major change to the coronal part of the tooth.
Ex vivo comparison of digital images with conventional radiographs for detection of simulated voids in root canal filling material
Authors: Kositbowornchai S. , Hanwachirapong D. , Somsopon R. , Pirmsinthavee S. , Sooksuntisakoonchai N. 
Published: March 2006

AbstractAim  To compare the diagnostic potential of direct digital images with conventional radiographs for the detection of simulated root canal voids.Methodology  The root canals of 80 extracted maxillary incisors with straight root canals were prepared and filled and the specimens divided into two groups: (i) a group of 40 teeth without voids; and, (ii) a group of 40 teeth with voids created in the root filling. Each root was imaged using the paralleling technique with a CCD‐based digital system and F‐speed film. Totally, there were 240 images: conventional radiographs (n = 80), digital images (n = 80) and digital zoomed images at 2× magnification (n = 80). These were interpreted for voids by a radiologist (without prior knowledge of the distribution of the voids). The reliability of the radiologist was confirmed using Cohen's Kappa Statistic, with the kappa value found to be >0.08. The sensitivity, specificity and predictive values were calculated. The differences in sensitivity and specificity between the imaging systems were then assessed using the Exact McNemar significance probability at the 95% significance level.Results  The sensitivities (95% CI) of conventional radiographs, digital images and zoomed images were 0.68 (0.57–0.78), 0.83 (0.74–0.91) and 0.80 (0.71–0.89), respectively. The specificities of the conventional radiographs, digital and zoomed images were 0.80 (0.71–0.89), 0.83 (0.74–0.91) and 0.83 (0.74–0.91), respectively. The positive predictive values (95% CI) were 0.77 (0.68–0.86), 0.83 (0.74–0.91) and 0.82 (0.74–0.90), respectively. The negative predictive values (95% CI) were 0.71 (0.61–0.81), 0.83 (0.74–0.91) and 0.80 (0.72–0.89), respectively. There were no significant differences between the sensitivity and specificity of digital images and conventional radiographs, and of digital images and zoomed images during the detection of voids in root fillings (P > 0.05).Conclusions  Under the conditions of this laboratory study, the diagnostic performance of digital images and conventional radiographs, and between the digital images and digital zoomed images for simulated void detection in root fillings were not significantly different.
MTA versus Portland cement as repair material for furcal perforations: a laboratory study using a polymicrobial leakage model
Authors: De‐Deus G. , Petruccelli V. , Gurgel‐Filho E. , Coutinho‐Filho T. 
Published: March 2006

AbstractAim  To compare the ability of Portland cement and mineral trioxide aggregate (MTA) to prevent coronal leakage through repaired furcal perforations in molar teeth.Methodology  The pulp chambers of 36 human mandibular molar teeth were accessed and the root canal orifices were located. The roots were horizontally sectioned in the middle third. Composite resin was used to fill the root canal orifices and the apical end of the roots. Perforations were created in the centre of the pulp chamber floor using a size 3 round bur. Thirty teeth were divided into two groups (n = 15) and a further six teeth served as controls. In G1, all 15 perforation defects were repaired with MTA while in G2, Portland cement was used. Each tooth was inserted in a silicone tube (bacterial reservoir) with the region containing the perforation protruding through the end. The system was sterilized and placed in a glass flask containing sterile brain heart infusion medium (BHI). The reservoirs were filled with human saliva mixed in BHI and system was incubated at 37 °C and checked daily for the appearance of turbidity in the BHI broth during the following 50 days. The leakage data were analysed statistically by a log‐rank test (P < 0.05).Results  Eight (53%) of the 15 samples of the MTA group (G1) and nine (60%) of the 15 samples of the Portland cement group (G2) were fully contaminated at 50 days. There was no statistically significant difference between the two groups (P > 0.05).Conclusion  Portland cement and MTA demonstrated a similar ability to seal furcal perforations.
The relation between apical periodontitis and root‐filled teeth in patients with periodontal treatment need
Authors: Stassen I. G. K. , Hommez G. M. G. , De Bruyn H. , De Moor R. J. G. 
Published: March 2006

AbstractAim  To investigate a number of clinical and treatment variables that might have influenced the prevalence of apical periodontitis in root‐filled teeth in a population of periodontally compromised patients.Methodology  This investigation was a retrospective cross‐sectional study on data collected from periodontal charts in addition to intra‐oral full‐mouth radiographs from patients attending the Department of Periodontology of the Dental School of the Ghent University Hospital. Periodontal parameters (clinical attachment loss and the lowest marginal bone level, the history of periodontal treatment), endodontic treatment (length, homogeneity and overall quality of the root filling) and the quality of coronal restorations were related to the prevalence of apical periodontitis. A total of 272 root‐filled teeth in 94 patients were evaluated.Results  The periapical condition was significantly influenced by the quality of the root filling and the coronal filling (P < 0.05). More apical periodontitis was seen when the coronal level of the root filling exceeded the marginal bone level (P < 0.005). The marginal periodontal condition seemed to influence the periapical status. Teeth with apical periodontitis were associated with significantly more extended marginal bone loss (P < 0.001). Significantly less apical periodontitis was seen in patients that had received marginal periodontal treatment (P < 0.005), compared with untreated periodontal patients.Conclusions  Signs of periodontal disease, as reflected by marginal bone loss, are of importance for the periapical condition of root‐filled teeth. Efforts should be taken in preventing spread of infection through the periodontal‐endodontic pathway by periodontal infection control and a high quality of root filling and coronal filling. Care should also be taken to seal the coronal cavity up to the level of the root filling, where it is advisable to reduce the coronal level of the root filling below or at least at the level of the surrounding marginal bone.
On the causes of persistent apical periodontitis: a review
Authors: Nair P. N. R. 
Published: March 2006

AbstractApical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors – located within the inflamed periapical tissue – that can interfere with post‐treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non‐resolving periapical lesions that are seen as asymptomatic radiolucencies post‐treatment.
The influence of haemostatic agents on healing of healthy human dental pulp tissue capped with calcium hydroxide
Authors: Silva A. F. , Tarquinio S. B. C. , Demarco F. F. , Piva E. , Rivero E. R. C. 
Published: March 2006

AbstractAim  To investigate the hypothesis that different haemostatic agents could impair the histological response of human pulps capped with calcium hydroxide.Methodology  Forty‐five third molars scheduled for extraction were selected. Class I cavities with pulp exposures were prepared. Three agents were used to control bleeding: 0.9% saline solution (control, n = 14), 5.25% sodium hypochlorite (n = 16) and 2% chlorhexidine digluconate (n = 15). The pulps were dressed with hard‐setting calcium hydroxide cement. After 7, 30 or 90 days, teeth were extracted, formalin‐fixed and prepared for histochemical techniques. The biological response was categorized using the following criteria: inflammatory response, soft tissue organization, reactionary dentine and reparative dentine. Data were submitted to statistical analysis, using nonparametric Kruskal–Wallis one‐way analysis of variance on ranks. Differences amongst groups were detected using Dunn's method.Results  The statistical analysis disclosed that whilst inflammatory response decreased over time, reactionary dentine deposition and reparative dentine formation increased in the latter periods of evaluation (P < 0.05). The three agents had similar performances for all criteria evaluated. The conventional pulp response to calcium hydroxide was observed over time, and complete pulp healing was observed in 88% of the specimens after 90 days.Conclusion  The three haemostatic agents did not impair the healing process following pulp exposure and capping with calcium hydroxide at different time intervals investigated.
Biological effects of flowable resin composite on erythrocytes and lymphocytes using an in vitro model
Authors: Yamaguchi H. , Suzuki S. , Kobayashi K. , Arai T. 
Published: March 2006

AbstractAim  The purpose of the study was to evaluate the biological effects of a flowable resin composite on erythrocytes and rat spleen lymphocytes (RSL) using an in vitro model.Methodology  Rat spleen lymphocytes were placed into microcentrifuge tubes as a pulp model. An artificial pulp exposure was made through the top of the microcentrifuge tube with a 16G needle. The exposure site was filled with a flowable resin composite and photo‐polymerized, and the other specimens were not polymerized. The survival rates were determined by a haemocytometer. Red blood cell (RBC) suspension (0.5%) was reacted with the flowable resin composite. The haemolytic activity was evaluated at room temperature (20 °C) using a supernatant of each sample by measuring 545 nm of absorbency with a spectrophotometer. To evaluate the effect of flowable resin composite on RBCs, supernatant and precipitated samples were analysed by sodium dodecyl sulphate–polyacrylamide gel (SDS–PAGE).Results  The cell survival rate of the polymerized group was significantly lower compared with that of the nonpolymerized group at the same areas (P < 0.05). The values of haemolysis (absorbency) were 2.16 for the polymerized group, 2.14 for the nonpolymerized group, and 2.18 for the control group (saline). There were no significant differences among them (P > 0.05). The protein component in the supernatant and precipitate exhibited the same reaction with flowable resin composite regardless of the completion of the polymerization, resulting in no change of protein band mobility on SDS–PAGE.Conclusions  The degree of haemolysis was not influenced by the completion of polymerization. The flowable resin composite tested provoked an adverse effect on lymphocytes when it was not polymerized and the degree of haemolysis was not affected by the status of the polymerization.
Preventing sleep problems in infants: a randomized controlled trial
Authors: Kerr Susan M. , Jowett Sarah A , Smith Lorraine N 
Published: March 2006

In the pre‐school years sleep problems are one of the most common subjects on which parents seek advice from health professionals In the majority of cases a sleepless child causes significant stress within the family, and if parents do not obtain sufficient sleep this can have a detrimental effect on then: physical and emotional well‐being In a small number of cases a child who wakes frequently and will not settle back to sleep may be at risk of physical abuse In recent years it has been suggested that it may be possible to prevent sleep problems developing by providing parents with advice in the post‐natal period Parents have stated that they find this type of intervention helpful, however, there has been no attempt to establish whether a preventive approach is effectiveThe aim of this research was to evaluate the efficacy of health education in reducing the incidence of sleep problems Adopting an experimental approach, participants were randomly allocated to a control group or an intervention group Parental knowledge of sleep and settling behaviour was manipulated when the children in the intervention group were 3 months old The sleeping behaviour of the infants in both groups was compared 6 months later, when the children were 9 months old Data was collected from 86 families in the intervention group and 83 families in the control group A comprehensive analysis of the sleeping behaviour demonstrated that a significantly smaller percentage of babies in the intervention group had settling and night‐waking difficulties than in the control group
Couples' experiences of infertility: a phenomenological study
Authors: Imeson Margaret , McMurray Anne 
Published: March 2006

If nurses are to work effectively with families in contemporary society, their practice activities must be appropriately informed Families exposed to new technologies, such as in vitro fertilization (IVF) require care that is sensitive to then: particular experience Infertile couples have been the subject of a substantial body of research, however, most studies to date focus on the physiological effects of infertility and do not take into account the context in which the experience takes place, or the meanings that people assign to this experienceThe purpose of this study was to examine in‐depth the experience of couples undergoing IVF treatment for infertility A phenomenological approach was adopted for the study A purposive sample of six couples was selected for interview Data were generated from taped interviews and the researcher's observational field notes Data analysis was in accordance with the procedure outlined by Colaizzi (1978) Interview responses were categorized by examining the participants' transcripts and identifying significant statements and meanings Themes which emerged from the statements were then identified, and cross‐case comparisons were made to confirm or modify these themesFour key themes emerged from the data life changes, powerlessness, hope‐disappointment cycle, and social isolation All couples undergoing infertility treatment experienced life changes which included lifestyle changes, various physical and emotional changes, and changes in their relationships There was a perceived loss of control over many aspects of their lives Couples also described a cycle, alternating feelings of hope and disappointment Most of the couples reported feelings of social isolation associated with being infertile, that were intensified by having to deal with the inappropriate responses of othersFindings from this study will add to the knowledge base on infertility, and contribute to recommendations for improving the way nurses guide, counsel, and support infertile couples
Medieval Prisons: Between Myth and Reality, Hell and Purgatory*
Authors: Geltner Guy 
Published: March 2006

AbstractWhen were medieval prisons founded? What was life inside them like? How did contemporary observers perceive them? Addressing such questions, this article brings together over a century of scholarship that undermines the traditional dating of the prison's “birth,” sheds light on the tolerable realities of medieval captivity, and identifies a range of contemporary interpretations of prison life and spaces.