bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐term dynamics and community structure of freshwater gastropods exposed to parasitism and other environmental stressors
Authors: GÉRARD CLAUDIA , CARPENTIER ALEXANDRE , PAILLISSON JEAN‐MARC 
Published: November 2007

Summary1. Freshwater communities are subject to various abrupt environmental disturbances and increasing pollution levels in their habitat. According to the nature and the periodicity of disturbances (i.e. punctuated, recurrent or continuous), one may expect different kinds of response of the target gastropod communities.2. The gastropod community of a French lake has been investigated for 10 years to study its responses to three main environmental disturbances: supra‐seasonal droughts, recurrent proliferations of cyanobacteria and parasitism by trematodes. The relationship between this latter factor, considered as a continuous stressor, and the gastropod community was a particular focus.3. A total of 13 280 gastropods belonging to 17 species (mostly Pulmonata with Planorbidae as the dominant family) have been sampled in the lake over the 10‐year time series. Species composition of the gastropod community varied strongly during the study period as did species richness (0–14, mean of 6.5 ± 0.4 species) and abundance of gastropods (0–4456, mean of 192 ± 72 individuals). Trematode larvae belonging to 11 morphotypes of cercariae were detected in 15 of the 17 species of gastropods and had a total prevalence of 2.9%.4. Droughts (punctuated stressor) were responsible for the disappearance of nearly all gastropod species, and thus represent a severe environmental stressor for them. Nevertheless, the extent of this stressor was limited since the gastropod community was highly resilient.5. Recurrent proliferations of toxic cyanobacteria (recurrent stressor) coincided with the large decline of the gastropod community, corresponding to a strong decrease in abundance and species richness. Intoxication of gastropods by toxic cyanobacteria was demonstrated by the bioaccumulation of microcystins in all gastropod tissues.6. Trematode parasitism (continuous stressor) did not affect the gastropod community despite the possibly strong impact of parasites on some host species (those with monthly prevalence as high as 100% at some times). Indeed, abundance and species richness of gastropods were scarcely influenced by trematode prevalence or species richness.
Northern map turtles (Graptemys geographica) derive energy from the pelagic pathway through predation on zebra mussels (Dreissena polymorpha)
Authors: BULTÉ GRÉGORY , BLOUIN‐DEMERS GABRIEL 
Published: November 2007

Summary1. Zebra mussels (Dreissena polymorpha) derive their energy from the pelagic energy pathway by filtering plankton. Because zebra mussels occur in high densities in littoral habitats, they potentially constitute an important trophic link between littoral consumers and pelagic energy sources. Northern map turtles (Graptemys geographica) are widespread in North America and consume zebra mussels.2. We used stable isotopes analyses to quantify the flow of energy from the pelagic pathway to northern map turtles and to infer the contribution of zebra mussels to map turtle biomass. We then built a bioenergetic model to estimate the annual intake of zebra mussels by northern map turtles in Lake Opinicon, Ontario, Canada.3. Stable isotopes analyses indicated that zebra mussels constitute between 0% and 14% of the diet of males and between 4% and 36% of the diet of females. Assuming that zebra mussels account for all of the pelagic contribution, we estimated that map turtles consume 3200 kg of zebra mussels annually. Because female map turtles are much larger than males and consume more zebra mussels, they are responsible for 95% of the zebra mussel biomass ingested annually.4. The pelagic pathway supports an important part of the standing crop biomass of map turtles in Lake Opinicon. We highlight the importance of freshwater turtles in lake ecosystems. Unravelling the trophic interactions mediated by freshwater turtles will lead to a more integrated picture of lake ecosystems.
Double‐square‐root one‐way wave equation prestack tau migration in heterogeneous media
Authors: Cheng Jiubing , Ma Zaitian , Geng Jianhua , Wang Huazhong 
Published: November 2007

ABSTRACTIn this paper, source‐receiver migration based on the double‐square‐root one‐way wave equation is modified to operate in the two‐way vertical traveltime (τ) domain. This tau migration method includes reasonable treatment for media with lateral inhomogeneity. It is implemented by recursive wavefield extrapolation with a frequency‐wavenumber domain phase shift in a constant background medium, followed by a phase correction in the frequency‐space domain, which accommodates moderate lateral velocity variations. More advanced τ‐domain double‐square‐root wave propagators have been conceptually discussed in this paper for migration in media with stronger lateral velocity variations. To address the problems that the full 3D double‐square‐root equation prestack tau migration could meet in practical applications, we present a method for downward continuing common‐azimuth data, which is based on a stationary‐phase approximation of the full 3D migration operator in the theoretical frame of prestack tau migration of cross‐line constant offset data. Migrations of synthetic data sets show that our tau migration approach has good performance in strong contrast media. The real data example demonstrates that common‐azimuth prestack tau migration has improved the delineation of the geological structures and stratigraphic configurations in a complex fault area.Prestack tau migration has some inherent robust characteristics usually associated with prestack time migration. It follows a velocity‐independent anti‐aliasing criterion that generally leads to reduction of the computation cost for typical vertical velocity variations. Moreover, this τ‐domain source‐receiver migration method has features that could be of help to speed up the convergence of the velocity estimation.
Prevalence and technical quality of root fillings in Dakar, Senegal
Authors: Touré B. , Kane A. W. , Sarr M. , Ngom C. T. H. , Boucher Y. 
Published: November 2007

AbstractAim  To examine the prevalence and technical quality of root fillings and the periapical status of root‐filled teeth in a subpopulation of Dakar, Senegal.Methodology  Full‐mouth periapical radiographs were obtained from 208 consecutive adults presenting as new patients to the Dental Service of the University. The occurrence and technical quality of root fillings were assessed for each root according to the apical extent of the root fillings and its density. The periapical status was evaluated using the Periapical Index Scoring System with a PAI > 2 indicating periapical disease. The presence of coronal restorations and posts was also noted. Statistical analysis was performed with the chi‐square test with a significance level set at P < 0.05%.Results  Of the 6234 teeth examined, 2.6% were root filled. A PAI > 2 was associated with 56.1% of the filled roots. Only 17.7% of the root fillings were technically acceptable and 26.2% of these were associated with a PAI > 2. In roots with unacceptable root fillings, 62.5% had a PAI > 2. Unacceptable root fillings were associated with a higher prevalence of periapical disease (P < 0.001). A post was seen in 18.9% of the filled roots with 66.2% associated with a PAI > 2. A permanent coronal restoration was present in 78.5% of the filled roots, of which 50.7% had a PAI > 2 vs 75.7% for no permanent restoration. At least one periapical lesion was seen in 59.6% of the subjects.Conclusion  The results indicate a low prevalence of teeth with radiographic periapical disease, a low prevalence of root‐filled teeth and a high prevalence of unacceptable root fillings.
Influence of multiple clinical use on fatigue resistance of ProTaper rotary nickel‐titanium instruments
Authors: Vieira E. P. , França E. C. , Martins R. C. , Buono V. T. L. , Bahia M. G. A. 
Published: November 2007

AbstractAim  To examine the influence of clinical use on the occurrence of deformation and fracture and on the fatigue resistance of ProTaper rotary instruments.Methodology  Root canal treatments were performed on patients using the ProTaper rotary system. Ten sets of instruments were used by an experienced endodontist, each set in five molars. Another 10 sets of instruments were used by the same operator, each set in eight molars. In addition, 10 sets of instruments were used, each set in five molars, by undergraduate students with no clinical experience with the system. After clinical use, S1, S2, F1 and F2 instruments were analysed for damage by optical and scanning electron microscopy. The used sets, along with a control group of 12 sets of new instruments, were then tested in a bench device for fatigue resistance.Results  The use of the ProTaper rotary instruments by an experienced endodontist allowed for the cleaning and shaping of the root canal system of up to eight molars without fracture. During the students work, six instruments fractured. Fatigue resistance decreased upon clinical use for all instruments analysed.Conclusions  Fatigue resistance of used instruments was reduced, but no significant change was observed amongst the instruments used for shaping the canals of five and eight molars. Operator experience affected the occurrence of fracture and plastic deformation during shaping.
Dental behavioural management problems and dental caries prevalence in 3‐ to 6‐year‐old Swedish children born preterm
Authors: BROGÅRDH‐ROTH SUSANNE , STJERNQVIST KARIN , MATSSON LARS 
Published: November 2007

Background.  Today, most children born preterm survive without major impairments. But high frequencies of cognitive and behavioural difficulties arise. Studies on dental behavioural management problems (DBMP) in these children are lacking. In addition, studies on caries prevalence are few and inconclusive.Aim.  This study aims to compare the frequency of behavioural problems and poor compliance with dental treatment in preschool children born preterm with those born full‐term. The prevalence of caries was also studied.Methods.  The study group included 187 children born between 23 and 32 weeks of gestation. The control group constituted full‐term children matched by age, sex, immigrant background, and dental operator. DBMP, number of dental visits, missed appointments, and caries between ages 3 and 6 were noted.Results.  At age 3, but not at age 6, the prevalence of DBMP at clinical examinations was significantly higher in preterm children compared with the control group. Of the children who received dental treatments during preschool years, preterm children displayed significantly more DBMP. No significant difference in dental visits or in caries prevalence was found. Preterm children, however, missed significantly more dental appointments.Conclusion.  Children born preterm display a higher prevalence of DBMP at dental examinations and treatments during preschool years.
Enhancing staff attitudes, knowledge and skills in supporting the self‐determination of adults with intellectual disability in residential settings in Hong Kong: a pretest–posttest comparison group design
Authors: Wong P. K. S. , Wong D. F. K. 
Published: November 2007

AbstractBackground  The ecological perspective recognizes the critical role that is played by rehabilitation personnel in helping people with intellectual disability (ID) to exercise self‐determination, particularly in residential settings. In Hong Kong, the authors developed the first staff training programme of its kind to strengthen the competence of personnel in this area. The purpose of this study was to examine the effectiveness of staff training in enhancing residential staff's attitudes, knowledge and facilitation skills in assisting residents with ID to exercise self‐determination.Methods  A pretest–posttest comparison group design was adopted. Thirty‐two participants in an experimental group attended a six‐session staff training programme. A 34‐item self‐constructed scale was designed and used for measuring the effectiveness of the staff training.Results  The results showed that the experimental group achieved statistically significant positive changes in all domains, whereas no significant changes were found in the comparison group.Conclusions  The findings provided initial evidence of the effectiveness of staff training that uses an interactional attitude–knowledge–skills model for Chinese rehabilitation personnel. The factors that contributed to its effectiveness were discussed and recommendations for future research were made.
Genetic variation and phylogeography of free‐living mouse species (genusMus) in the Balkans and the Middle East
Authors: MACHOLÁN M. , VYSKOČILOVÁ M. , BONHOMME F. , KRYŠTUFEK B. , ORTH A. , VOHRALÍK V. 
Published: November 2007

AbstractThis work presents a study of the distribution and pattern of variation throughout the ranges of three free‐living mouse species of the genusMus—M. macedonicus,M. spicilegus, and aM. cypriacus— based on sequencing of two segments of the mitochondrial DNA (mtDNA) control region. The study shows a similar level of variability in the three species and suggests their recent population expansion. The highest proportion of variation is found within populations indicating low genetic structuring. Phylogenetic analysis confirms the significant divergence of a mitochondrial lineage ofM. macedonicusfrom Israel, recently described as a new subspecies,M. macedonicus spretoides. Conversely, no genetic hiatus is revealed between European and Asian populations ofM. macedonicus macedonicus. Although phylogenetic relationships amongM. spicileguspopulations could not be unravelled precisely, the results suggest a recent westward expansion of the species. The mtDNA divergence betweenM. macedonicusandM. spicilegusis 7.3%, suggesting their split betweenc.700 000 and 1 million years ago. These dates correspond with a coalescent estimate about 720 000 years ago. On the other hand,M. cypriacusappeared almost twice as divergent from the former species (4.5%) as from the latter (8.8%) suggesting a divergence ofc.430 000–610 000 years ago (coalescent ≈ 490 000 years ago) and 830 000–1.2 million years ago (coalescent ≈ 780 000 years ago), respectively. Approximate times of population expansion have also been estimated for all taxa and groups of populations. Existence of several glacial refuges and various colonization scenarios are discussed; since all estimated divergence times fall within interglacial periods it seems that climatic oscillations did not play a crucial role in the evolution of the three species.
High variation and strong phylogeographic pattern among cpDNA haplotypes in Taxus wallichiana (Taxaceae) in China and North Vietnam
Authors: GAO L. M. , MÖLLER M. , ZHANG X.‐M. , HOLLINGSWORTH M. L. , LIU J. , MILL R. R. , GIBBY M. , LI D.‐Z. 
Published: November 2007

AbstractWe studied the phylogeography of Chinese yew (Taxus wallichiana), a tree species distributed over most of southern China and adjacent regions. A total of 1235 individuals from 50 populations from China and North Vietnam were analysed for chloroplast DNA variation using polymerase chain reaction–restriction fragment length polymorphism of the trnL‐F intron‐spacer region. A total of 19 different haplotypes were distinguished. We found a very high level of population differentiation and a strong phylogeographic pattern, suggesting low levels of recurrent gene flow among populations. Haplotype differentiation was most marked along the boundary between the Sino‐Himalayan and Sino‐Japanese Forest floristic subkingdoms, with only one haplotype being shared among these two subkingdoms. The Malesian and Sino‐Himalayan Forest subkingdoms had five and 10 haplotypes, respectively, while the relatively large Sino‐Japanese Forest subkingdom had only eight. The strong geography–haplotype correlation persisted at the regional floristic level, with most regions possessing a unique set of haplotypes, except for the central China region. Strong landscape effects were observed in the Hengduan and Dabashan mountains, where steep mountains and valleys might have been natural dispersal barriers. The molecular phylogenetic data, together with the geographic distribution of the haplotypes, suggest the existence of several localized refugia during the last glaciation from which the present‐day distribution may be derived. The pattern of haplotype distribution across China and North Vietnam corresponded well with the current taxonomic delineation of the three intraspecific varieties of T. wallichiana.
Mechanical barriers to introgressive hybridization revealed by mitochondrial introgression patterns inOhomopterusground beetle assemblages
Authors: NAGATA NOBUAKI , KUBOTA KOHEI , YAHIRO KATSURO , SOTA TEIJI 
Published: November 2007

AbstractTo reveal the role of diverged body size and genital morphology in reproductive isolation among closely related species, we examined patterns of, and factors limiting, introgressive hybridization between sympatricOhomopterusground beetles in central Japan using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences. We sampled 17 local assemblages that consisted of two to five species and estimated levels of interspecific gene flow using the genetic distance,DA, and maximum‐likelihood estimates of gene flow. Sharing of haplotypes or haplotype lineages was detected between six of seven species that occurred in the study areas, indicating mitochondrial introgression. The intensity and direction of mitochondrial gene flow were variable among species pairs. To determine the factors affecting introgression patterns, we tested the relationships between interspecificDAand five independent variables: difference in body size, difference in genital size, phylogenetic relatedness (nuclear gene sequence divergence), habitat difference, and species richness of the assemblage. Body and genital size differences contributed significantly to preventing gene flow. Thus, mechanical isolation mechanisms reduce the chance of introgressive hybridization between closely related species. Our results highlight the role of morphological divergence in speciation and assemblage formation processes through mechanical isolation.
Increased levels of reactive oxygen species and expression of a cytoplasmic aconitase/iron regulatory protein 1 homolog during the early response of maize pulvini to gravistimulation
Authors: CLORE A. M. , DOORE S. M. , TINNIRELLO S. M. N. 
Published: November 2007

ABSTRACTThe maize (Zea mays L.) stem pulvinus is a disc of tissue located apical to each node that functions to return a tipped stem to a more upright position via increased cell elongation on its lower side. We investigated the possibility that reactive oxygen species (ROS) and hydrogen peroxide (H2O2), in particular, are involved in the gravitropic response of the pulvinus prior to initiation of the growth response by employing the cytochemical stain 3,3′‐diaminobenzidine (DAB). DAB polymers were found in the bundle sheath cells of gravistimulated pulvini in association with amyloplasts after 1 min of gravistimulation, and the signal spread throughout the cytosol of these cells by 30 min. Furthermore, treatment of maize stem explants containing pulvini with 1 mm H2O2 on their upper sides caused reversal of bending polarity. Similar, though less dramatic, results were obtained via application of 1 mm ascorbic acid to the lower side of the explants. In addition, we determined that a maize cytoplasmic aconitase/iron regulatory protein 1 (IRP1) homolog is up‐regulated in the pulvinus bundle sheath cells after gravistimulation using suppressive subtractive hybridization PCR (SSH PCR), real‐time RT‐PCR and in situ hybridization. Although we do not yet know the role of the IRP1 homolog in the pulvinus, the protein is known to be a redox sensor in other systems. Collectively, our results point to an increase in ROS quite early in the gravitropic signalling pathway and its possible role in determining the direction of bending of the pulvini. We speculate that an ROS burst may serve to link the physical phenomenon of amyloplast sedimentation to the changes in cellular biochemistry and gene expression that facilitate directional growth.
Adjuvant Effects of Bacillus Calmette–Guerin DNA or CpG‐oligonucleotide in the Immune Response to Taenia solium Cysticercosis Vaccine in Porcine
Authors: Guo Y.‐J. , Wu D. , Wang K.‐Y. , Sun S.‐H. 
Published: November 2007

AbstractThe immune stimulation properties of CpG‐oligonucleotides (CpG‐ODN) containing a central unmethylated CpG motif could be useful for vaccination against parasite infection. However, the high cost of synthetic CpG‐ODN has limited its use in veterinary vaccines. In this study, we investigated whether genomic DNA derived from Mycobacterium bovis bacillus Calmette–Guerin (BCG‐DNA) could be used as an effective adjuvant to enhance the immunogenicity and the protective capacity of recombinant cC1 antigen (rcC1) against pig cysticercosis. Pigs were vaccinated with rcC1 plus CpG‐containing DNA adjuvants (BCG‐DNA or CpG‐ODN) or rcC1 alone. Immunization with rcC1 alone induced a Th1‐biased response, whereas coadministration of rcC1 with BCG‐DNA or CpG‐ODN increased levels of IgG2, IFN‐γ, percentage of CD8+ and specific proliferation of peripheral blood mononuclear cells. Four weeks after the last immunization, pigs were infected with Taenia solium eggs. A high level of protection (81%) was induced by rcC1 immunization that was not significantly increased by the CpG‐containing DNA. These data indicate that coadministration of rcC1 plus BCG‐DNA or CpG‐ODN significantly enhanced Th1 response but did not improve the level of the protection induced.
Regulatory CD4+CD25+ T Cells Prevent Thymic Dysfunction in Experimental Chronic Colitis
Authors: Veltkamp C. , Ruhwald R. , Veltkamp R. , Giese T. , Stremmel W. 
Published: November 2007

AbstractChronic colitis in T‐cell deficient Tgε26 mice develops due to a dysfunction of the thymus which generates colitogenic T cells after bone marrow (BM) transplantation. Regulatory CD4+CD25+ T cells have been shown to prevent colitis in this model by normalizing the peripheral T‐cell pool. We tested the hypothesis that T‐cell normalization takes place in the thymus. Tgε26 mice were transplanted with BM (BM→Tgε26 mice) and consequently received either CD4+CD25+ or CD4+CD25− cells from syngenic wild type mice. Furthermore, untransplanted Tgε26 mice received CD4+CD25+ or CD4+CD25− cells or complete mesenteric lymph node cells. Transfer of regulatory. CD4+CD25+ cells normalized the total number of thymocytes and the percentage and number of double positive CD4+CD8+ cells in transplanted mice while percentage of single positive CD4+ and CD8+ thymocytes in BM→Tgε26 mice was reduced upon CD4+CD25+ transfer. Timing of CD4+CD25+ cell injection was important as transfer later than 7 days after BM transplantation failed to prevent abnormal thymic T‐cell distribution in BM→Tgε26 mice. Isolated CD4+CD25+ cell transfer without preceding BM transplantation failed to reconstitute thymic architecture. Differences of thymic cell composition could not be exclusively explained by presence or absence of colitis, respectively, because 19 days after BM transplantation when both groups showed no histological signs of colitis, animals transferred with CD4+CD25+ T cells had a significantly higher percentage and number of CD4+CD25+ thymocytes and CD4+Foxp3+ cells than BM→Tgε26 mice. In conclusion, early CD4+CD25+ cotransfer prevents thymic dysfunction which underlies immune‐mediated bowel inflammation in BM→Tgε26 mice.