Ammoniakemissiereductie : opties en condities voor zelfregulering

This study focuses on the policy side of the ammonia emission problem. The starting point in this is that in developing new policy options, the possibilities for aligning government measures with the business practice of cattle farmers occupy centre stage. To this end, the possibilities of self(regulation are examined as a counterpart for the current central hierarchical regulatory system. When working out the details of selfregulation, it is important to find a balance between the opportunities available for cattle farmers to take measures themselves and achieving the public objectives for which cattle farmers have to give account of themselves to the government: from 'government' to 'governance

Spatial and temporal variation in population genetic diversity in seagrasses and the implications for resilience

Seagrass ecosystems are highly productive and fulfil vital roles in the coastal environment as ecosystem engineers and keystone species. Unfortunately, anthropogenic pressures have resulted in a significant loss of seagrass habitat and associated ecosystem services. The complex and unpredictable nature of these pressures, and their increasing extent and intensity globally, makes resilience-based ecosystem management a valuable approach. Resilience-based management requires knowledge on processes enhancing ecosystem resilience and on actions supporting these processes. Genetic diversity, which is the allelic variation among individuals of a population, has been recognised as one of the pillars of resilient ecosystems. Genetic diversity within a population can contribute to its capacity to resist and recover from disturbances and to adapt to changing conditions. Thus far, however, our understanding of the spatial and temporal variation in genetic diversity in seagrasses has been very limited, hindering the use of genetic data in seagrass management. This knowledge gap was addressed within this thesis, through three separate approaches: a global review on population genetic diversity of seagrass populations and two field studies which focused on variation in diversity in two seagrass species across different spatial and temporal scales. The review aimed to assess global variation in the genetic diversity of seagrasses across key biological attributes and geographical distributions. The first field study aimed to investigate temporal variation in clonal and genetic diversity and clone composition of the widely distributed, colonising tropical seagrass Halodule uninervis. The second field study aimed to characterise the spatial patterns in genetic diversity and population genetic structure of Amphibolis antarctica across its distribution along a strong salinity gradient in Shark Bay, Western Australia. The review explored how commonly reported clonal and genetic diversity metrics varied across family, life history strategy, reproductive mode, bioregion, and latitude. This was achieved through a global systematic literature review focused on publications with data on genetic diversity of natural seagrass populations. A total of 154 articles were found with genetic diversity data from 1622 populations, of which the majority (1483 populations) used microsatellite markers. There was large variation in diversity across populations and weak spatial patterns, indicating that local conditions appear to strongly influence genetic diversity as they overwhelm global patterns. There were also significant effects of life history strategy, reproductive mode, and family on clonal and genetic diversity metrics. Lower clonal richness and higher inbreeding coefficient were found in colonising compared to opportunistic and persistent taxa and higher clonal richness was observed in monoecious compared to dioecious and hermaphroditic taxa. The first field study assessed temporal variation in clonal and genetic diversity, and clone composition of the colonising seagrass H. uninervis in the short (6 months) and long-term (4-6 years) along ~1000 km of West Australian coastline at 15 sites and across a range of disturbance conditions. A total of 44 Single Nucleotide Polymorphisms (SNPs) were used to estimate population genetic diversity. Diversity varied among sites, but varied more for clonal than genetic diversity metrics, e.g. clonal richness ranged from 0.00-0.83 and observed heterozygosity ranged from 0.27-0.34. Clonal and genetic diversity showed unexpected temporal stability over both timescales for all populations, despite temporal changes in clone composition. Furthermore, 19% of clones persisted over 4-6 years, and a maximum clonal age up to 3905 years was estimated. The second field study characterised genetic diversity and structure, and tested for evidence of local adaptation, in the temperate seagrass A. antarctica across an extreme environmental salinity gradient (\u3e 20) in the Shark Bay World Heritage Site, Australia. In addition, this salinity gradient was characterised and hydrodynamic connectivity among sites was explored through modelling. Amphibolis antarctica was genotyped at 10 sites across this gradient using Double digest Restriction site Associated DNA sequencing (ddRADseq), resulting in 6523 loci. Intermediate levels of genotypic diversity (global R = 0.50 ± 0.06 SE) and observed heterozygosity (global HO = 0.30 ± 0.00 SE), and high genetic connectivity among most sites indicates potential for genetic resilience at a population level with pathways for recovery. Modelled salinity patterns showed extreme differences in mean monthly salinity among (\u3e 20) and within (\u3e 15) sites. Only 11 of the 6523 loci identified as potentially adaptive, but were not associated with salinity, providing no evidence of local adaption, and suggesting phenotypic plasticity to salinity variation instead. These studies provide important insights into the genetic diversity, population dynamics and longevity of seagrasses and the potential to contribute to population resilience, with implications for seagrass management. First, the finding of large variation in genetic diversity measures and population dynamics, like genet persistence, among populations within species indicate that it is important to collect site-specific genetic data and to understand local conditions when incorporating genetic diversity into seagrass management. Second, the unexpected longevity in a colonising taxa rivalled that found in persistent seagrasses. Since longevity contributes to the stability and persistence of populations over time, these findings indicate that a re-evaluation of the persistence of genets and populations in seagrasses across life history strategies is needed. Third, the temporal stability in diversity observed in H. uninervis indicates it is feasible to include clonal and genetic diversity in seagrass monitoring since genetic assessments can provide an estimate of genetic diversity that is valid for multiple years. Fourth, the persistence of individual genets observed in a colonising taxa means there are opportunities for the assisted recovery of colonising seagrass meadows through the introduction of new clones. Finally, this research showed that the estimated natural recovery period for seagrass can be tens to thousands of years, which indicates that assisted recovery could be a valuable tool within seagrass management

Experimental harvest in a tropical seagrass meadow leads to shift in associated benthic communities

Abstract Seagrass meadows represent key ecosystems in coastal areas worldwide, hosting a great biodiversity of associated communities and thereby providing a large range of ecosystem services. In this study we present an experimental approach to investigate the effects of seagrass losses on related macrofauna assemblages. Over a three year period, seagrass canopies were removed in experimental plots and changes in epifauna, infauna and respective functional groups were recorded. The experimental removal of seagrass leaves resulted in a decline of 74% of overall macrofaunal abundance and the loss of several taxa. The immediate response of associated communities was followed by the establishment of an alternative assemblage, characterized by an increased number of bioturbators and deposit feeders. The colonization of disturbed seagrass plots by burrowing shrimps (Callianassidae) might have hindered the reestablishment of seagrass after the removal. Our findings highlight the important role of seagrasses as habitat forming species that provide relevant functioning and services in coastal ecosystems

The effect of aspirin and nonsteroidal anti-inflammatory drug use after diagnosis on survival of oesophageal cancer patients

Background:Aspirin use has been shown to lower incidence and mortality in cancer patients. The aim of this population-based study was to determine the effect of postdiagnosis low-dose aspirin use on survival of patients with oesophageal cancer.Methods:Patients with oesophageal cancer (1998-2010) were selected from the Eindhoven Cancer Registry and linked with outpatient pharmacy data regarding aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Users were subdivided into both prediagnosis and postdiagnosis or only postdiagnosis users. Parametric survival models with an exponential (Poisson) distribution were used with non-specific death as endpoint.Results:In this study 560 patients were included. Overall, 157 patients (28.0%) were non-users, 293 patients (52.3%) pre-and postdiagnosis (89 aspirin and 204 NSAID users) and 110 patients (19.6%) only postdiagnosis users (16 aspirin and 94 NSAID users). Postdiagnosis aspirin use was associated with overall survival (RR 0.45 (95% CI 0.34-0.60; P<0.001); adjusted rat

The influence of BRAF and KRAS mutation status on the association between aspirin use and survival after colon cancer diagnosis

Background: Use of aspirin after diagnosis of colon cancer has been associated with improved survival. Identification of cancer subtypes that respond to aspirin treatment may help develop personalized treatment regimens. The aim of this study was to investigate the influence of BRAF and KRAS mutation status on the association between aspirin use and overall survival after colon cancer diagnosis. Methods: A random selection of 599 patients with colon cancer were analyzed, selected from the Eindhoven Cancer Registry, and BRAF and KRAS mutation status was determined. Data on aspirin use (80 mg) were obtained from the PHARMO Database Network. Parametric survival models with exponential (Poisson) distribution were used. Results: Aspirin use after colon cancer diagnosis was associated with improved overall survival in wild-type BRAF tumors, adjusted rate ratio (RR) of 0.60 (95% CI 0.44-0.83). In contrast, aspirin use in BRAF mutated tumors was not associated with an improved survival (RR 1.11, 95% CI 0.57-2.16). P-value for interaction was non-significant. KRAS mutational status did not differentiate in the association between aspirin use and survival. Conclusion: Low-dose aspirin use after colon cancer diagnosis was associated with improved survival in BRAF wild-type tumors only. However, the large confidence interval of the rate ratio for the use of aspirin in patients with BRAF mutation does not rule out a possible benefit. These results preclude BRAF and KRAS mutation status to be used as a marker for individualized treatment with aspirin, if aspirin becomes regular adjuvant treatment for colon cancer patients in the future

Renewing clinical applications for commonly used medications in gastrointestinal cancer

This thesis tried to unravel the epidemiological background of the current evidence on the effect of aspirin on gastrointestinal cancer. Bayer, Pfizer, ChipsoftLUMC / Geneeskund

Seagrass Removal Leads to Rapid Changes in Fauna and Loss of Carbon

Seagrass habitats are important natural carbon sinks, with an average of ~14 kg C m−2 buried in their sediments. The fate of this carbon following seagrass removal or damage has major environmental implications but is poorly understood. Using a removal experiment lasting 18 months at Gazi Bay, Kenya, we investigated the impacts of seagrass loss on sediment topography, hydrodynamics, faunal community structure and carbon dynamics. Sediment pins were used to monitor surface elevation. The effects of seagrass removal on water velocity was investigated using Plaster of Paris dissolution. Sediment carbon concentration was measured at the surface and down to 50 cm. Rates of litter decay at three depths in harvested and control treatments were measured using litter bags. Drop samples, cores, and visual counts of faunal mounds and burrows were used to monitor the impact of seagrass removal on the epifaunal and infaunal communities. Whilst control plots showed sediment elevation, harvested plots were eroded (7.6 ± 0.4 and −15.8 ± 0.5 mm yr−1 respectively, mean ± 95% CI). Carbon concentration in the surface sediments was significantly reduced with a mean carbon loss of 2.21 Mg C ha−1 in the top 5 cm. Because sediment was lost from harvested plots, with a mean difference in elevation of 3 cm, an additional carbon loss of up to 2.54 Mg C ha−1 may have occurred over the 18 months. Seagrass removal had rapid and dramatic impacts on infauna and epifauna. There was a loss of diversity in harvested plots and a shift toward larger bodied, bioturbating species, with a significant increase in mounds and burrows. Buried seagrass litter decomposed significantly faster in the harvested compared with the control plots. Loss of seagrass therefore led to rapid changes in sediment dynamics and chemistry driven in part by significant alterations in the faunal community