Loozen G.,Health Science University |
Ozcelik O.,Cukurova University |
Boon N.,Ghent University |
De Mol A.,Health Science University |
And 4 more authors.
Journal of Clinical Periodontology | Year: 2014
Aim Although the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20 key oral bacteria was assessed in health and disease and more importantly a closer look was given to the inter-bacterial relationships. Materials and methods A blinded microbiological database was analysed in this cross-sectional, retrospective study. The database was constructed based on microbiological analyses of samples from 6308 patients, with gradations of periodontitis (healthy to periodontitis). Data concerning the abundance of 20 oral bacteria and probing pocket depth were provided. Results Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Porphyromonas micra and Porphyromonas intermedia showed a clear increase in abundance and prevalence with increasing pocket depth. Correlation matrices illustrated that almost all microorganisms were in one way correlated to other species and most of these correlations were significant. Several beneficial bacteria showed strong correlations with other beneficial bacteria. Conclusion Knowledge on bacterial correlations can pave the way for new treatment options focusing on restoring the shifted balance. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Aerenhouts D.,Vrije Universiteit Brussel |
Aerenhouts D.,University of Antwerp |
Clarys P.,Vrije Universiteit Brussel |
Taeymans J.,Vrije Universiteit Brussel |
And 4 more authors.
PLoS ONE | Year: 2015
A recommended field method to assess body composition in adolescent sprint athletes is currently lacking. Existing methods developed for non-athletic adolescents were not longitudinally validated and do not take maturation status into account. This longitudinal study compared two field methods, i.e., a Bio Impedance Analysis (BIA) and a skinfold based equation, with underwater densitometry to track body fat percentage relative to years from age at peak height velocity in adolescent sprint athletes. In this study, adolescent sprint athletes (34 girls, 35 boys) were measured every 6 months during 3 years (age at start = 14.8 ± 1.5yrs in girls and 14.7± 1.9yrs in boys). Body fat percentage was estimated in 3 different ways: 1) using BIA with the TANITA TBF 410; 2) using a skinfold based equation; 3) using underwater densitometry which was considered as the reference method. Height for age since birth was used to estimate age at peak height velocity. Cross-sectional analyses were performed using repeated measures ANOVA and Pearson correlations between measurement methods at each occasion. Data were analyzed longitudinally using a multilevel cross-classified model with the PROC Mixed procedure. In boys, compared to underwater densitometry, the skinfold based formula revealed comparable values for body fatness during the study period whereas BIA showed a different pattern leading to an overestimation of body fatness starting from 4 years after age at peak height velocity. In girls, both the skinfold based formula and BIA overestimated body fatness across the whole range of years from peak height velocity. The skinfold based method appears to give an acceptable estimation of body composition during growth as compared to underwater densitometry in male adolescent sprinters. In girls, caution is warranted when interpreting estimations of body fatness by both BIA and a skinfold based formula since both methods tend to give an overestimation. © 2015 Aerenhouts et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Vanmaercke M.,Catholic University of Leuven |
Vanmaercke M.,Fund for Scientific Research Flanders |
Poesen J.,Catholic University of Leuven |
Verstraeten G.,Catholic University of Leuven |
And 2 more authors.
Geomorphology | Year: 2011
Our understanding about the regional variation of Sediment Yield (SY) in Europe and its scale dependency currently relies on a limited number of data for mainly larger river systems. SY is the integrated result of all erosion and sediment transporting processes operating in a catchment and is therefore of high value for environmental studies and monitoring purposes. Most global assessments of SY consider catchment area (A), climate and topography as the main explanatory variables. However, it is still unclear if these factors also control regional variations of SY within Europe. This paper aims at bridging this gap. Therefore, we i) present a large database of SY-values which was constructed through an extensive literature review; ii) describe the spatial patterns of SY across Europe; and iii) explore its relation with A, climate, and topography.In total, sediment yield data from 1794 different locations throughout Europe were collected (507 reservoirs and 1287 gauging stations), representing a minimum of 29,203 catchment-year data. Only SY-data measured at gauging stations or derived from reservoir siltation rates over a period of a minimum of one year were included in the database. This database comprises a large range of catchment areas (A): i.e from small upland catchments (≥ 0.01. km2) to major European river basins (≤1,360,000. km2). An overview of the collected SY-data is provided and sources of uncertainty on the available data are discussed.Despite potentially large uncertainties on several of the individual SY-values, analysis of this database indicates clear spatial patterns of SY in Europe. The temperate and relatively flat regions of Western, Northern and Central Europe generally have relatively low SY-values (with ca. 50% of the SY<40tkm-2yr-1 and ca. 80% of the data <200tkm-2yr-1), while Mediterranean and Mountainous regions generally have higher SY-values (with around 85% of the SY-data >40tkm-2yr-1 and more than 50% of the data >200tkm-2yr-1). These differences are attributed to a combination of factors, such as differences in climate, topography, lithology and land use. Although larger differences in SY were found between the climatic regions than between topographic zones, it is currently difficult to identify the individual importance of the various controlling factors of SY. SY-A relationships were calculated for the entire dataset and for subgroups stratified according to the measurement method (gauging stations or reservoir surveys), range of the catchment area, climatic region, topographic zone of the river outlet, and major European river system. Although typically a negative relationship between SY and A is expected due to a decrease in topsoil erosion rates on more gentle slopes and an increase in sediment deposition with an increase in catchment size, this relationship was found to be generally very weak and subject to a lot of scatter. Furthermore, results illustrate important differences in scale dependency: whereas a weak but significant negative trend is generally observed for the temperate and relatively flat regions, no significant or even positive trends were observed in mountain regions and Mediterranean Europe. When only larger river catchments (i.e. > 100. km2 and especially >10,000. km2) are considered, catchment area exerted a larger control on SY. These findings confirm previous studies and indicate that the relationship between SY, spatial scale and other controlling factors is often complex and non-linear. © 2011 Elsevier B.V.
Dirikx A.,Catholic University of Leuven |
Dirikx A.,Fund for Scientific Research Flanders |
Gelders D.,Catholic University of Leuven
Environmental Communication | Year: 2010
This article studies the relationship between the ideology of newspapers and their climate change coverage. Previous research has focused on the British press (Carvalho, 2007; Carvalho and Burgess, 2005). Our research broadens this scope to the French and Dutch media. The results show that the ideology of newspapers in the Netherlands is not related to climate change coverage, while in France the ideology of newspapers is related to some key aspects of climate change coverage, i.e., the presentation of the necessity of actions against climate change and the tone of climate change coverage. The findings suggests that ideological cultures play a role in the coverage of climate change in countries in which global warming has brought about much discussion in the political field and that are characterized by a highly competitive media landscape which is historically related to the political field. © 2010 Taylor & Francis.
Meeusen R.,Vrije Universiteit Brussel |
Roelands B.,Vrije Universiteit Brussel |
Roelands B.,Fund for Scientific Research Flanders |
Spriet L.L.,University of Guelph
Nestle Nutrition Institute Workshop Series | Year: 2013
Caffeine can improve exercise performance when it is ingested at moderate doses (3-6 mg/kg body mass). Caffeine also has an effect on the central nervous system (CNS), and it is now recognized that most of the performance-enhancing effect of caffeine is accomplished through the antagonism of the adenosine receptors, influencing the dopaminergic and other neurotransmitter systems. Adenosine and dopamine interact in the brain, and this might be one mechanism to explain how the important components of motivation (i.e. vigor, persistence and work output) and higher-order brain processes are involved in motor control. Caffeine maintains a higher dopamine concentration especially in those brain areas linked with 'attention'. Through this neurochemical interaction, caffeine improves sustained attention, vigilance, and reduces symptoms of fatigue. Other aspects that are localized in the CNS are a reduction in skeletal muscle pain and force sensation, leading to a reduction in perception of effort during exercise and therefore influencing the motivational factors to sustain effort during exercise. Because not all CNS aspects have been examined in detail, one should consider that a placebo effect may also be present. Overall, it appears that the performance-enhancing effects of caffeine reside in the brain, although more research is necessary to reveal the exact mechanisms through which the CNS effect is established. © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.