Construction of data-driven models to predict the occurrence of planktonic species in the North-Sea

Marine habitat suitability models typically predict the potential distribution of organisms based on basic abiotic variables such as salinity, oxygen concentrations, temperature fluctuations (Gogina & Zettler, 2010) or sediment class information (Degraer et al., 2008; Willems et al., 2008). Recently, Dachs & Méjanelle (2010) claimed that the modification of biota composition due to marine pollution is a factor to be taken into account in marine habitat suitability models. Although the anthropogenic pressure on the environment has been exponentially increasing during the last six decades (Dachs & Méjanelle, 2010), the global effect of human inputs on oceanic phytoplankton remains unknown (Echeveste et al., 2010). A limited number of studies have assessed the impact of anthropogenic stressors on phytoplankton in marine environments at a global level (Faust et al., 2003; Magnusson et al.,2008). In order to fill this knowledge gap, this research tries to determine to what extent pollution data can be used to predict the occurrence of the phytoplanktonic organisms compared to basic abiotic variables. Here we explored this issue by developing classification trees relating physical-chemical variables with the occurrence of the potential harmful toxic algae Odontella sinensis

Periodic mesoporous organosilicas for application as low-k dielectric materials

In semiconductor manufacturing, a low-k dielectric is a material with a small dielectric constant relative to silicon dioxide. In digital circuits, insulating dielectrics separate the conducting parts from one another. As components have scaled down and transistors have gotten closer and closer together, the insulating dielectrics have thinned to the point where charge builds up and crosstalk adversely affects the performance of the device. Replacing the silicon dioxide with a low-k dielectric of the same thickness reduces parasitic capacitance, enables faster switching speeds and reduces the power consumption. Besides the low-k property, the materials must have a good mechanical strength and they have to be hydrophobic, because adsorbed water increases the dielectric constant of the material. In this contribution, periodic mesoporous organosilicas are synthesized and evaluated for their low-k applicability. Firstly, the best synthesis conditions and stabilities of these PMOs in powder form are investigated. Secondly, the PMOs with the best properties are processed as thin films and the synthesis procedure is further optimized to obtain good quality porous films with ultra low dielectric constants. Finally, because closed pores are required for a good reliability of the low-k material, two pore sealing methods are developed and evaluated for their pore sealing efficiency

Optimum sol viscosity for stable electrospinning of silica nanofibres

Silica nanofibres have, due to their excellent properties, promising characteristics for multiple applications such as filtration, composites, catalysis, etc. Silica nanofibres can be obtained by combining electrospinning and the sol–gel process. To produce silica nanofibres most of the time organic solutions are applied containing a carrying polymer, which is afterwards removed by a thermal treatment to form pure ceramic nanofibres. Although electrospinning of the pure silica precursors without carrying polymer is preferred, the parameters influencing the stability of the electrospinning process are however largely unknown. In addition, this knowledge is essential for potential upscaling of the process. In this study, the optimum viscosity to electrospin in a stable manner is determined and the way to obtain this viscosity is evaluated. Sols with a viscosity between 120 and 200 mPa.s could be electrospun in a stable way, resulting in uniform and beadless nanofibres. Furthermore, this viscosity region corresponded with nanofibres having the lowest mean nanofibre diameters. Electrospinning with diluted sols was possible as well, but electrospinning of the fresh sols was more stable. These results illustrate the importance of the viscosity and degree of crosslinking of the sol for the stable electrospinning of silica nanofibres and demonstrate that upscaling of the electrospinning process of silica nanofibres is feasibl

Morphological changes in 15 skeletal muscles of horses after 8 weeks of aquatraining

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