Pathway choice in DNA double strand break repair: Observations of a balancing act

Proper repair of DNA double strand breaks (DSBs) is vital for the preservation of genomic integrity. There are two main pathways that repair DSBs, Homologous recombination (HR) and Non-homologous end-joining (NHEJ). HR is restricted to the S and G2 phases of the cell cycle due to the requirement for the sister chromatid as a template, while NHEJ is active throughout the cell cycle and does not rely on a template. The balance between both pathways is essential for genome stability and numerous assays have been developed to measure the efficiency of the two pathways. Several proteins are known to affect the balance between HR and NHEJ and the complexity of the break also plays a role. In this review we describe several repair assays to determine the efficiencies of both pathways. We discuss how disturbance of the balance between HR and NHEJ can lead to disease, but also how it can be exploited for cancer treatment

A METHOD FOR SUPPORTING USERS\u27COMPREHENSIVE LEARNING

In this paper, we present an educational intervention carried out in one of the object organizations of our research project.1 This type of education provides users with knowledge and qualifications which can compensate defects in the IS. The method focuses on organizational communication and coordination. Five phases of intervention are described: interviews, group discussions, lectures, simulation, and personal guidance. We evaluate the method by discussing the results and effects of the intervention

The Fundamental Plane in RX J0142.0+2131: a galaxy cluster merger at z=0.28

We present the Fundamental Plane (FP) in the z = 0.28 cluster of galaxies RX J0142.0+2131. There is no evidence for a difference in the slope of the FP when compared with the Coma cluster, although the internal scatter is larger. On average, stellar populations in RX J0142.0+2131 have rest-frame V-band mass-to-light ratios (M/L_V) 0.29+-0.03 dex lower than in Coma. This is significantly lower than expected for a passively-evolving cluster formed at z_f=2. Lenticular galaxies have lower average M/L_V and a distribution of M/L_V with larger scatter than ellipticals. Lower mass-to-light ratios are not due to recent star formation: our previous spectroscopic observations of RX J0142.0+2131 E/S0 galaxies showed no evidence for significant star-formation within the past ~4 Gyr. However, cluster members have enhanced alpha-element abundance ratios, which may act to decrease M/L_V. The increased scatter in the RX J0142.0+2131 FP reflects a large scatter in M/L_V implying that galaxies have undergone bursts of star formation over a range of epochs. The seven easternmost cluster galaxies, including the second brightest member, have M/L_V consistent with passive evolution and z_f = 2. We speculate that RX J0142.0+2131 is a cluster-cluster merger where the galaxies to the east are yet to fall into the main cluster body or have not experienced star formation as a result of the merger.Comment: 4 pages, 2 figures, accepted for publication in ApJ Letter

Eye Movements: a Window on Sensory and Motor Deficits

__Abstract__ Eye movements can be used as a tool for investigating neural mechanisms of both sensory and motor deficits. Not only does the oculomotor system comprise the entire transformation from sensory input to the generation of movement, also its accessibility, its ability to learn and remember, and the exhibition of both voluntary and reflexive behavior, make the oculomotor system a good diagnostic aid in understanding sensory-motor pathologies. Furthermore, recording eye movements generates data that are suitable for quantative analysis. Eye movement behavior can be investigated in different ways. Obviously, movement control can be analysed by looking at factors such as the timing, metrics and dynamics of the movement. A more general high-level view is provided when the planning of the movement is examined. Likewise, testing reflexive behavior in response to sensory stimuli can offer information about how the sensory information is being processed. Therefore, looking at eye m