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Studying the origin and use of the oldest prehistoric pottery in northern Belgium using high-end mass spectrometric methods
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The neural mechanisms underlying Chinese visual word recognition : three exploratory studies and a comparison with English
No full textEen minder bekende oorzaak van plotse scherpe lagerugpijn
No full textEen 41-jarige man presenteert zich met acute lagerugpijn na het optillen van een
zwaar voorwerp. MRI toont een acute Schmorlse nodule aan de dekplaat van de tweede
lumbaalwervel (L2). Schmorlse noduli zijn herniaties van de nucleus pulposus door de
eindplaat, en zijn meestal asymptomatisch, maar zeldzaam kunnen ze de oorzaak zijn
van acute pijn. Symptomatische Schmorlse noduli kenmerken zich op MRI door reactief
beenmergoedeem rondom het letsel. De behandeling is voornamelijk symptomatisch,
met pijnstilling en kinesitherapi
Exploring violence against the police in Chinese policing practice
No full textViolence against the police is a serious threat to the safety of both police officers and police agencies. Although much effort has been made by police agencies to prevent violence against police officers, frontline police officers continue to suffer from violent attacks. Thus, this research explores violence against police in Chinese policing practice and analyses the various groups involved in violent attacks. The value of this research is that it can support further understanding of how violence against the police occurs, and can contribute to the development of prevention policies.This study raises a number of questions about the occurrence processes and behavior patterns of violence against police, which include police units, offenders, police officers, and police victims. n conclusion, this dissertation explains how violence against the police occurs and the role of multiple groups in it. This PhD dissertation offers several insights into the further development of prevention policies and the reduction of police casualties
In search of resultative constructions : a corpus-based comparison of Germanic and Romance languages
No full textAssessing the evolutionary robustness of anti-biofilm combination therapy
No full textBesides the well-known problems associated with antibiotic resistance, treatment of bacterial infections is hampered by the fact that bacteria often reside in biofilms. One of the typical properties of biofilm cells is reduced susceptibility to antimicrobial agents, due to lack of penetration of antibiotics, and biofilm-specific protective stress responses. In addition, specific phenotypes with low metabolic activity are induced in biofilms, likely providing an additional mechanism of tolerance. A strategy to increase the antibacterial activity of antibiotics is the use of potentiators. These are compounds that have no antimicrobial activity on their own, but increase the antimicrobial effect of conventional antibiotics in combination therapy. Because potentiators in contrary to antibiotics, do not directly kill pathogens, they are thought to exert less selective pressure on bacteria, and would consequently result in less development of resistance. The aim of this dissertation was to evaluate if combinations of potentiators and antibiotics are ‘evolution-proof’ (i.e., if potentiators would slow down or prevent the development of antibiotic resistance). To this end, two Gram-negative pathogens, Pseudomonas aeruginosa and Burkholderia cenocepacia, that are known to cause difficult to treat, biofilm-associated infections, were experimentally evolved in presence of a combination therapy. To make the experimental results more relevant for the in vivo situation, P. aeruginosa which is a major pathogen in cystic fibrosis, was evolved in a synthetic medium that mimics the environment of the cystic fibrosis lung, and B. cenocepacia was evolved in a non-vertebrate in vivo host. The experiments in this dissertation show that potentiators are able to increase the antimicrobial effect of antibiotics against biofilms and in in vivo models. However, resistance against potentiators can develop, indicating that combination therapies are not by definition ‘evolution-proof’
Soil erosion and nutrient availability in tropical forests of the Congo Basin
No full textThe importance of tropical forests in the global climate system is widely known.
Through their high productivity they represent a significant global carbon reservoir.
Preserving this function needs a continuous supply of nutrients, mainly nitrogen (N)
and phosphorus (P). However, the availability and biogeochemical cycling of these
nutrients is highly variable in space and time and the understanding of different
nutrient loss pathways is still lacking. The influence of soil erosion on the availability
of these nutrients in pristine forests of the tropics is not well understood. To gain a
better mechanistic understanding of the aquatic loss processes of N and P, we
monitored different headwater streams in three distinct tropical forests of the
Congo Basin and determined the influence of soil erosion on soil N. This knowledge
is important to assess the response of these ecosystems to changing climate and land
use.
To assess the importance of soil erosion in tropical forests and export of sediments
and nutrients from drainage basins, the first part of the thesis focussed on the
fundamental understanding of the dynamics and drivers of sediment export in
headwater streams of a tropical lowland forest and a deciduous Miombo woodland.
We used high temporal resolution turbidity data and analysed the turbiditydischarge hysteresis patterns during storm events. Although these forest systems
are situated in very old and stable landscapes, the obtained sediment yields were
substantial and comparable to forests in more geomorphic active sites of the tropics.
Although the Miombo only experiences a five-month wet season, similar annual
sediment export was found as for the lowland forest, due to the lower vegetation
cover. Furthermore, results showed that storm events exported 30% and 68% of the
annual sediment yield in the lowland and the Miombo, respectively.
In Chapter three, it was shown that soil erosion and storm events also play a crucial
role in aquatic nutrient export from these forest ecosystems. At both sites, N and P
were dominantly exported in particulate or dissolved organic forms and the yields of
those nutrient constituents were driven by intense discharge pulses due to storm
events. This highlights the need to include samples of those events in a sampling
campaign to get reliable annual export yields. This was not possible for the montane
forest monitoring site (Chapter four), resulting in a large uncertainty in the sediment
and nutrient yield estimates. However, best estimates of the long-term baseflow
dataset highlighted the same trend to the importance of particulate and dissolved
organic N and P export. Although these losses are significant, there is no indication
that erosion leads to local nutrient limitations in the N and P rich montane and
lowland forests. The goal of Chapter five was to evaluate if soil erosion influences
soil N at the catchment scale. For this, stable isotope signatures of soil N have been
analysed as an integrator of N cycling processes. Results showed that only in the
Miombo woodland, stable isotopic signatures of soil N were influenced by
topography and soil erosion, indicating erosional effects on N cycling.
In the last part of this thesis, the influence of land use in the lowlands on aquatic
sediment and nutrient export was examined. Results from a field campaign, during
which baseflow was intensively sampled, revealed that there was significant higher
export of dissolved organic N and particulate inorganic P, while the yields of nitrate
were lower in an agricultural catchment compared to the pristine forest catchment.
Continuous sensor measurements indicated that our findings most probably
underestimated these differences because of the lack of storm event data.
The results of this thesis highlight the importance of particulate N and P losses from
pristine tropical forests and their inclusion in biogeochemical studies are
important, even in so believed low erosive ecosystems. The predicted increase in
rainfall intensity and the ongoing loss of primary forests will further enhance the
importance of these processes