bluuebunny/crossref_metadata_2025_split huggingface dataset:
A prospective study of dental anxiety in a cohort of children followed from 5 to 9 years of age
Authors: TICKLE MARTIN , JONES CLARE , BUCHANNAN KATIE , MILSOM KEITH M. , BLINKHORN ANTHONY S. , HUMPHRIS GERRY M. 
Published: March 2009

Background.  The development of dental anxiety in children is poorly understood.Aims.  The aims of this study were to measure changes in dental anxiety over time and to examine the relationship between anxiety, dental care, and other factors.Design.  A prospective cohort study of children in the north‐west of England followed from 5 to 9 years of age. The participants were clinically examined and their parents completed the same questionnaire at 5 and 9 years.Results.  The majority (54.3%N = 38) of participants who were anxious at 5 years were no longer anxious at 9 years, but a large proportion of children who were anxious at 5 remained anxious at 9 years of age (45.7%N = 32). During the follow‐up period, a larger proportion of children developed anxiety (11.7%N = 85) than the proportion of children who were reported as being anxious at baseline (8.8%N = 70). At 9 years of age, dental anxiety was significantly associated with girls; parental anxiety; a history of extraction; and irregular, asymptomatic dental visiting. These factors were also significantly associated with dental anxiety at 5 years old.Conclusions.  Dental anxiety was cumulative in the study population over time, and its development influenced by multiple variables. Results suggest that adverse conditioning and vicarious learning are both important in the development of this condition.
Spring Normalized Difference Vegetation Index (NDVI) predicts annual variation in timing of peak faecal crude protein in mountain ungulates
Authors: Hamel Sandra , Garel Mathieu , Festa‐Bianchet Marco , Gaillard Jean‐Michel , Côté Steeve D. 
Published: March 2009

Summary

In recent years, the Normalized Difference Vegetation Index (NDVI) has been used to assess the relationships between habitat quality and animal life‐history traits. Since numerous ecological studies now use NDVI rather than perform direct vegetation assessments, field validations are essential to provide confidence in the biological significance of NDVI estimates. While some studies have compared NDVI with plant biomass, very few examined the relationship between NDVI and changes in vegetation quality.
Using data from two long‐term studies of alpine ungulates, we assessed the relationship between two NDVI indices and the date of peak in faecal crude protein (FCP), which represents temporal variability in the availability of high‐quality vegetation. We also evaluated if NDVI data could predict annual variation in the timing of spring green‐up.
In both populations, integrated NDVI in June was negatively correlated with the date of the peak in FCP, indicating that high integrated NDVI values corresponded to early springs in alpine habitats. Maximum NDVI increase during spring green‐up was positively correlated with the timing of peak FCP, illustrating that rapid increases in NDVI represented delayed springs.
Predicted values of date of peak FCP estimated each year from NDVI data satisfactorily fitted observed values, and prediction intervals included all observed values. These results suggest that NDVI can reliably predict variation over years in the timing of spring.
Synthesis and applications. Our long‐term studies demonstrate that a multi‐year time series of Normalized Difference Vegetation Index (NDVI) can reliably measure yearly changes in the timing of the availability of high‐quality vegetation for temperate herbivores. This finding therefore supports the use of NDVI as a proxy for vegetation attributes in population ecology and wildlife management studies.
Enhancement of Allee effects in plants due to self‐incompatibility alleles
Authors: Levin Donald A. , Kelley Christopher D. , Sarkar Sahotra 
Published: March 2009

Summary

Founder populations of plants are usually small and may become extinct due to many factors including inbreeding and low pollen transfer besides stochastic factors. This positive relationship between population size and individual fitness is taken as evidence of an Allee effect. Very few studies have quantitatively compared the influence of self‐incompatibility systems and S‐allele counts on the magnitude of observed Allee effects for different population sizes and seed and pollen dispersal distances.
This paper uses a stochastic, spatially explicit, individual‐based cellular automaton model to simulate the dynamics of newly established plant populations with sporophytic or gametophytic self‐incompatibility (SI) alleles and compares these to a null (Mendelian) population. Parameters varied in model simulation are the S‐allele count, the initial population size, and the pollen and seed dispersal distances. These parameters were studied over a wide range to assess their relative impact on population viability compared to the null case in order to model the effect of self‐incompatibility on population fitness.
The results indicate that Allee effects are enhanced and growth rates are slowed in newly established populations of species with S‐alleles relative to Mendelian populations, leading to enhanced extinction risk. They also show the importance of the relationship between pollen and seed dispersal ranges on the fitness of the population. Populations with sporophytic self‐incompatibility were more extinction‐prone than those with gametophytic SI, and the latter more so than Mendelian populations when all other factors were held constant.
Synthesis. Overall, the simulation results indicate that Allee effects in small populations are enhanced in plants with S‐alleles. Even in relatively large populations, S‐allele count controls the strength of observed Allee effects. A high S‐allele count is able to compensate for lower initial population size. Pollen and seed dispersal ranges had a similarly strong effect on the viability of populations with S‐alleles. These effects are stronger in populations with sporophytic self‐incompatibility than in those with gametophytic SI. Simulation results also indicate that S‐alleles were not lost to genetic drift over time, in contrast with some earlier studies of S‐allele systems displaying Allee effects.
Molecular genetic variation and population structure in morphologically differentiated cave and surface populations of the freshwater amphipod Gammarus minus
Authors: CARLINI DAVID B. , MANNING JOHN , SULLIVAN PATRICK G. , FONG DANIEL W. 
Published: March 2009

Abstract Gammarus minus is an important component of surface spring and cave ecosystems throughout Appalachia, and is a useful indicator of the hydrology and gene flow in freshwater communities. Gammarus minus populations occupying large cave passages (> 2 km) are usually troglomorphic, having reduced eyes, fewer ommatidia, larger body size, longer antennae, and reduced pigmentation relative to surface populations. We surveyed five cave stream and 10 surface spring populations for DNA sequence variation in the cytochrome c oxidase I (COI) and internal transcribed spacer 1 (ITS‐1) genes with an aim towards characterizing phylogeographical structure and comparing the nature of genetic variation in cave vs. surface populations. Although standing variation at both loci was rather low within populations, a significant degree of divergence and spatial structuring of populations was observed. Levels of genetic variation within cave and spring populations differed substantially, with caves harbouring significantly less variation at the COI locus than surface springs. Codon usage bias was significantly lower in caves, indicating that cave streams harbour smaller and/or more recently colonized populations. Overall these data indicate limited gene flow among populations and suggest that the cave populations sampled in this study are prone to bottlenecks, possibly due to larger temperature fluctuations and more frequent incidence of drought conditions associated with these particular cave habitats.
Sudden expansion of a single brown bear maternal lineage across northern continental Eurasia after the last ice age: a general demographic model for mammals?
Authors: KORSTEN MARJU , HO SIMON Y. W. , DAVISON JOHN , PÄHN BERIT , VULLA EGLE , ROHT MARIS , TUMANOV IGOR L. , KOJOLA ILPO , ANDERSONE‐LILLEY ZANETE , OZOLINS JANIS , PILOT MALGORZATA , MERTZANIS YORGOS , GIANNAKOPOULOS ALEXIOS , VOROBIEV ALEX A. , MARKOV NIKOLAI I. , SAVELJEV ALEXANDER P. , LYAPUNOVA ELENA A. , ABRAMOV ALEXEI V. , MÄNNIL PEEP , VALDMANN HARRI , PAZETNOV SERGEI V. , PAZETNOV VALENTIN S. , RÕKOV ALEXANDER M. , SAARMA URMAS 
Published: March 2009

AbstractThe brown bear has proved a useful model for studying Late Quaternary mammalian phylogeography. However, information is lacking from northern continental Eurasia, which constitutes a large part of the species’ current distribution. We analysed mitochondrial DNA sequences (totalling 1943 bp) from 205 bears from northeast Europe and Russia in order to characterize the maternal phylogeography of bears in this region. We also estimated the formation times of the sampled brown bear lineages and those of its extinct relative, the cave bear.Four closely related haplogroups belonging to a single mitochondrial subclade were identified in northern continental Eurasia. Several haplotypes were found throughout the whole study area, while one haplogroup was restricted to Kamchatka. The haplotype network, estimated divergence times and various statistical tests indicated that bears in northern continental Eurasia recently underwent a sudden expansion, preceded by a severe bottleneck. This brown bear population was therefore most likely founded by a small number of bears that were restricted to a single refuge area during the last glacial maximum. This pattern has been described previously for other mammal species and as such may represent one general model for the phylogeography of Eurasian mammals. Bayesian divergence time estimates are presented for different brown and cave bear clades. Moreover, our results demonstrate the extent of substitution rate variation occurring throughout the phylogenetic tree, highlighting the need for appropriate calibration when estimating divergence times.
Phylogeography and host race differentiation in the European mistletoe (Viscum album L.)
Authors: ZUBER D. , WIDMER A. 
Published: March 2009

AbstractMistletoes are bird dispersed, hemi‐parasitic shrubs infecting a large number of woody host plants. Chloroplast fragment length polymorphisms were used to study genetic differentiation among presumed host races, population genetic structure, and to elucidate the postglacial migration history of mistletoe (Viscum album) across the entire natural distribution range in Europe. The populations sampled belong to four closely related taxa, three of which are widely distributed and differ in their host trees, whereas a fourth taxon is rare and endemic to the Island of Crete. The molecular analysis of chloroplast DNA variation supported the distinction of these four taxa. We further found evidence for phylogeographical structure in each of the three widely distributed host races. Independent of host race, mistletoe haplotypes from Turkey were distinct and distant from those found elsewhere in Europe, suggesting that highly differentiated populations, and possibly new taxa, exist at the range limit of the species.
AtMBD9 modulates Arabidopsis development through the dual epigenetic pathways of DNA methylation and histone acetylation
Authors: Yaish Mahmoud W. F. , Peng Mingsheng , Rothstein Steven J. 
Published: March 2009

SummaryMutations within the Arabidopsis METHYL‐CpG BINDING DOMAIN 9 gene (AtMBD9) cause pleotropic phenotypes including early flowering and multiple lateral branches. Early flowering was previously attributed to the repression of flowering locus C (FLC) due to a reduction in histone acetylation. However, the reasons for other phenotypic variations remained obscure. Recent studies suggest an important functional correlation between DNA methylation and histone modifications. By investigating this relationship, we found that the global genomic DNA of atmbd9 was over‐methylated, including the FLC gene region. Recombinant AtMBD9 does not have detectable DNA demethylation activity in vitro, but instead has histone acetylation activity. Ectopic over‐expression of AtMBD9 and transient DNA demethylation promotes flowering and causes partial recovery of the normal branching phenotype. Co‐immunoprecipitation assays suggest that AtMBD9 interacts in vivo with some regions of the FLC gene and binds to histone 4 (H4). Gene expression profile analysis revealed earlier up‐regulation of some flower‐specific transcriptional factors and alteration of potential hormonal and signal transducer axillary branching regulatory genes. In accordance with this result, AtMBD9 itself was found to be localized in the nucleus and expressed in the flower and axillary buds. Together, these results suggest that AtMBD9 controls flowering time and axillary branching by modulating gene expression through DNA methylation and histone acetylation, and reveal another component of the epigenetic mechanism controlling gene expression.
Oral N‐acetylcysteine attenuates pulmonary emphysema and alveolar septal cell apoptosis in smoking‐induced COPD in rats
Authors: CAI Shan , CHEN Ping , ZHANG Cheng , CHEN Jian‐Bo , WU Jie 
Published: March 2009

ABSTRACTBackground and objective:  The role of apoptosis in lung destruction in emphysema/COPD is increasingly being recognized. The relationship between anti‐oxidants and alveolar septal cell apoptosis in COPD lungs remains to be elucidated. The aim of this study was to investigate the effects of the anti‐oxidant, N‐acetylcysteine (NAC), on the development of emphysema and alveolar septal cell apoptosis in smoking‐induced COPD in rats.Methods:  Sprague–Dawley rats (n = 48) were randomly assigned to normal, COPD, sham and NAC groups. The effects of treatment were assessed by measuring the levels of vascular endothelial growth factor (VEGF) in BAL fluid by ELISA, VEGF and VEGF receptor‐2 (VEGFR2) protein expression by western blotting, and the apoptotic index (AI) of alveolar septal cells by terminal deoxynucleotidyl transferase dUTP nick‐end labelling (TUNEL) assay. Histopathological evaluations (mean linear intercept (MLI), destructive index (DI)) and lung function measurements were performed.Results:  FEV0.3/FVC and PEF were lower in the COPD group than in the normal group. MLI and DI were lower in the NAC‐treated group than in the COPD or sham‐treated groups. As confirmed by western blotting, the levels of VEGF in BAL fluid were higher in the NAC‐treated group than in the COPD group. VEGFR2 protein expression was higher in the NAC‐treated group than in the COPD group. The AI was significantly lower in the NAC‐treated group than in the COPD group. There was an inverse correlation between levels of VEGF in BAL fluid and the AI of alveolar septal cells.Conclusions:  NAC attenuates lung damage, pulmonary emphysema and alveolar septal cell apoptosis by partly reversing the decrease in VEGF secretion and VEGFR2 protein expression in smoking‐induced COPD in rats.
Influence of chunky graphite on mechanical and fatigue properties of heavy‐section cast iron
Authors: MOURUJÄRVI A. , WIDELL K. , SAUKKONEN T. , HÄNNINEN H. 
Published: March 2009

ABSTRACTThis research work aimed to find out the influences of the different amounts of chunky graphite on mechanical and fatigue properties of GJS 800 ductile cast iron. Chunky graphite has been a problem of heavy section thick‐walled ductile cast iron components. Chunky graphite is branched and interconnected as a network within eutectic cells and has been observed to form in thermal centres of heavy ductile cast iron sections during solidification. This research work proved that chunky graphite in the microstructure decreases the ultimate tensile strength, the elongation to fracture and fatigue life significantly, but does not influence on the yield stress of ductile cast iron GJS 800 substantially. Low nodular count and nodularity rate also decrease the fatigue life of ductile cast iron, and the difference of fatigue life of specimens containing chunky graphite or having low nodular count and nodularity rate is not large. Influence of the amount of chunky graphite on fatigue life increases until 20% chunky graphite content, and above that the fatigue life does not decrease substantially.
Forest fragmentation relaxes natural nest predation in an Afromontane forest
Authors: Spanhove T. , Lehouck V. , Boets P. , Lens L. 
Published: March 2009

AbstractNest predation is widely regarded as a major driver underlying the population dynamics of small forest birds. Following forest fragmentation and the subsequent invasion by species from non‐forested landscape matrices, shifts in predator communities may increase nest predation near forest edges. However, effects of human‐driven habitat change on nest predation have mainly been inferred from studies with artificial nests, despite being regarded as poor surrogates for natural ones. We studied variation in predation rates, and relationships with timing of breeding and characteristics of microhabitats and fragments, on natural white‐starred robin Pogonocichla stellata nests during three consecutive breeding seasons (2004–2007) in a Kenyan fragmented cloud forest. More than 70% of all initiated nests were predated during each breeding season. Predation rates nearly quadrupled between the earliest and the latest nests within a single breeding season, increased with distance to the forest edge, and decreased with the edge‐to‐area ratio of forest fragments. These spatial relationships oppose the traditional perception of edge and fragmentation effects on nest predation, but are in line with results from artificial nest experiments in other East African forests. In case of inverse edge and fragmentation effects on nest predation, such as shown in this study, species that tolerate edges for breeding may be affected positively, rather than negatively, by forest fragmentation, while the opposite can be expected for species restricted to the forest interior. The possibility of inverse edge effects, and its conservation implications, should therefore be taken into account when drafting habitat restoration plans.
Implications of predatory specialization for cranial form and function in canids
Authors: Slater G. J. , Dumont E. R. , Van Valkenburgh B. 
Published: March 2009

AbstractThe shape of the cranium varies widely among members of the order Carnivora, but the factors that drive the evolution of differences in shape remain unclear. Selection for increased bite force, bite speed or skull strength may all affect cranial morphology. We investigated the relationship between cranial form and function in the trophically diverse dog family, Canidae, using linear morphometrics and finite element (FE) analyses that simulated the internal and external forces that act on the skull during the act of prey capture and killing. In contrast to previous FE‐based studies, we compared models using a newly developed method that removes the effects of size and highlights the relationship between shape and performance. Cranial shape varies among canids based on diet, and different selective forces presumably drove evolution of these phenotypes. The long, narrow jaws of small prey specialists appear to reflect selection for fast jaw closure at the expense of bite force. Generalists have intermediate jaw dimensions and produce moderate bite forces, but their crania are comparable in strength to those of small prey specialists. Canids that take large prey have short, broad jaws, produce the largest bite forces and possess very strong crania. Our FE simulations suggest that the remarkable strength of skulls of large prey specialists reflect the additional ability to resist extrinsic loads that may be encountered while struggling with large prey items.
A synthetic NCAM‐derived mimetic peptide, FGL, exerts anti‐inflammatory properties via IGF‐1 and interferon‐γ modulation
Authors: Downer Eric J. , Cowley Thelma R. , Cox Fionnuala , Maher Francis O. , Berezin Vladimir , Bock Elisabeth , Lynch Marina A. 
Published: March 2009

AbstractMicroglial cell activity increases in the rat hippocampus during normal brain aging. The neural cell adhesion molecule (NCAM)‐derived mimetic peptide, FG loop (FGL), acts as an anti‐inflammatory agent in the hippocampus of the aged rat, promoting CD200 ligand expression while attenuating glial cell activation and subsequent pro‐inflammatory cytokine production. The aim of the current study was to determine if FGL corrects the age‐related imbalance in hippocampal levels of insulin‐like growth factor‐1 (IGF‐1) and pro‐inflammatory interferon‐γ (IFNγ), and subsequently attenuates the glial reactivity associated with aging. Administration of FGL reversed the age‐related decline in IGF‐1 in hippocampus, while abrogating the age‐related increase in IFNγ. FGL robustly promotes IGF‐1 release from primary neurons and IGF‐1 is pivotal in FGL induction of neuronal Akt phosphorylation and subsequent CD200 ligand expression in vitro. In addition, FGL abrogates both age‐ and IFNγ‐induced increases in markers of glial cell activation, including major histocompatibility complex class II (MHCII) and CD40. Finally, the proclivity of FGL to attenuate IFNγ‐induced glial cell activation in vitro is IGF‐1‐dependent. Overall, these findings suggest that FGL, by correcting the age‐related imbalance in hippocampal levels of IGF‐1 and IFNγ, attenuates glial cell activation associated with aging. These findings also highlight a novel mechanism by which FGL can impact on neuronal CD200 ligand expression and subsequently on glial cell activation status.
Centenarians – a useful model for healthy aging? A 29‐year follow‐up of hospitalizations among 40 000 Danes born in 1905
Authors: Engberg Henriette , Oksuzyan Anna , Jeune Bernard , Vaupel James W. , Christensen Kaare 
Published: March 2009

SummaryCentenarians surpass the current human life expectancy with about 20–25 years. However, whether centenarians represent healthy aging still remains an open question. Previous studies have been hampered by a number of methodological shortcomings such as a cross‐sectional design and lack of an appropriate control group. In a longitudinal population‐based cohort, it was examined whether the centenarian phenotype may be a useful model for healthy aging. The study was based on a complete follow up of 39 945 individuals alive in the Danish 1905 birth cohort on January 1, 1977 identified through the Danish Civil Registration System (DCRS). Data from the Danish Demographic Database and The Danish National Patient Register (in existence since 1977) were used. The 1905 cohort was followed up from 1977 through 2004 with respect to hospitalizations and number of hospital days. Survival status was available until December 2006. Danish centenarians from the 1905 cohort were hospitalized substantially less than their shorter‐lived contemporaries at the same point in time during the years 1977 through 2004. For example, at age 71–74, the proportion of nonhospitalized centenarians was 80.5% compared with 68.4% among individuals who died in their early 80s. This trend was evident in both sexes. As a result of their lower hospitalization rates and length of stay in hospital compared with their contemporaries, who died at younger ages, Danish centenarians represent healthy agers. Centenarians constitute a useful study population in the search for fixed traits associated with exceptional longevity, such as genotype.