Side channel dynamics

Side channels are commonly constructed to increase the discharge capacity of a river during peak flow conditions or to increase the ecological value of the river. Observations show that large aggradation occurs in the side channels. Therefore, such channels require regular and costly maintenance. The aim of this research is to better understand the mechanisms that drive the morphodynamic development of side channels and thereby, improve the design of side channels and reduce their maintenance needs. We studied the development of side channel in various ways and found that mechanisms such as a length difference between the downstream channels, sediment sorting at the bifurcation and varying hydrodynamic conditions have a large effect on the morphodynamic development of a side channel system. The mechanisms that are important are not the same for each side channel and can vary in time. Therefore, we propose three categories of side channel based on how the sediment that is deposited in the side channel is transported in the main channel: (1) bed load supplied, (2) suspended bed-material load supplied and (3) wash load supplied side channels. These categories can help in determining the main mechanisms that affect the development of a side channel system. In addition, we propose a method based on the categorization that can aid the design, operation and maintenance of side channels

Mechanisms for sediment fining in a side channel system

Side channels have been constructed in the Dutch river system to reduce flood risk and to increase the ecological value of the river. Some of these side channels show large aggradation and therefore require regular maintenance. Grain size measurements of the deposited sediment show that the bed of the side channel contains much finer sediment (0.2-0.3 mm) than the bed of the main channel (1-2 mm). This suggest that sorting occurs at the bifurcation of the side channel which likely affects the equilibrium state and the time scale of the side channel development. The objective is to reproduce the morphodynamic development with a 2D numerical model that allows for sorting processes. The dimensions of the system are based on the Waal River in the Netherlands

Grief following homicidal loss

People confronted with homicidal loss have to cope with separation distress, related to their loss, and traumatic distress, associated with the circumstances surrounding the death. These reactions are related to complicated grief and posttraumatic stress symptoms. Based on a questionnaire study among 312 homicidally bereaved individuals, it was found that on average of seven years after the murder, 33% of the bereaved individuals suffered from post-traumatic stress symptoms, and 82% of complicated grief symptoms. These complaints did not differ depending on whether the perpetrator was known or unknown or whether the perpetrator was a relative of the bereaved individual. Post-traumatic stress and complicated grief symptoms were found to be related to revenge, although no causal relationship could be established due to the cross-sectional design of the study. Post-traumatic stress- and complicated grief symptoms were also associated with negative cognitions about the self, catastrophic misinterpretations of one own grief reactions and depressive avoidance. Anxious avoidance and negative cognitions about the future were associated with thoughts and feelings of revenge. Based on a randomized controlled trial, it was found that bereaved individuals with high levels of posttraumatic stress- and complicated grief symptoms benefit from a treatment of eight sessions in which cognitive behavioral therapy and EMDR is applied

Tumor-specific proteins in human cancer

Normal cells grow, divide, communicate, and differentiate in a coordinated fashion. These highly complex processes are regulated by the programmed expression of different genes. It is generally assumed that tumor formation originates from alterations in genes involved in the control of cell proliferation. To get more insight in the process of tumorigenesis, many studies have focused on the detection of such altered genes followed by the elucidation of the function of the genes involved. Because chromosomal aberrations occur frequently in human cancer, they were suspected to form the basis of the alterations in the genes. Therefore, the earliest studies aimed at the identification of chromosomal breakpoints, were based on known cytogenetic aberrations, such as translocations. In this way, a considerable number of genes has been detected in which structural aberrations occur. The ultimate purpose of these studies was to elucidate the function of the proteins encoded by the altered genes, their role in tumorigenesis and the potentiality to be used as targets for specific tumor-therapy. Aberrant genes and proteins are also highly important from a diagnostic point of view, since they are only expressed in tumor cells. Therefore, the malignant cells distinguish themselves from normal cells by the presence of these particular, tumor-specific genes. As a consequence, aberrant proteins encoded by these genes are also tumor-specific and as such excellent phenotypic tumormarkers, called tumor-specific proteins (TSPs)