Methodiek Schoolverlatersinformatiesysteem 1999

Dit werkdocument gaat in op de methodiek die in het uitvoeringsjaar 1999 is gehanteerd binnen het schoolverlatersonderzoek zoals dat door het ROA wordt uitgevoerd. Dit betreft de enquêtes Registratie van Uitstroom en Bestemming van Schoolverlaters (RUBS), HBO-Monitor en WO-Monitor. Sinds 1996 is het ROA-schoolverlatersonderzoek in vergaande mate geïntegreerd. Hierdoor is een vergelijkbaar systeem ontstaan, het Schoolverlatersinformatiesysteem (SIS) genoemd, met gegevens over schoolverlaters uit vrijwel het gehele secundair en tertiair onderwijs. In het kader van het onderzoek binnen dit informatiesysteem is onder andere de statistische bijlage van Schoolverlaters tussen onderwijs en arbeidsmarkt 1999 gepubliceerd. Daarnaast zijn er nog twee specifieke rapportages verschenen namelijk, een rapport over de arbeidsmarktpositie van de afgestudeerden van het HBO en een rapport over de arbeidsmarktpositie van afgestudeerden van het kunstvakonderwijs. De lerarenopleidingen zullen in een aparte rapportage worden behandeld. Tevens zullen de belangrijkste resultaten van de WO-Monitor in een landelijke rapportage worden gepresenteerd. Het Schoolverlatersinformatiesysteem wordt financieel mogelijk gemaakt door de Ministeries van Onderwijs, Cultuur en Wetenschappen, Sociale Zaken en Werkgelegenheid en Landbouw, Natuurbeheer en Visserij, het Expertisecentrum voor Loopbaanvraagstukken LDC, de HBO-Raad, de VSNU en de deelnemende onderwijsinstellingen. Bij de uitvoering van het onderzoek werkt het ROA samen met DESAN Marktonderzoek b.v. te Amsterdam en STOAS Onderzoek te Wageningen. Binnen het ROA is de projectleiding van het Schoolverlatersinformatiesysteem in handen van dr. R.K.W. van der Velden en dr. M.H.J. Wolbers. Dit werkdocument is samengesteld door E.J. Potma en P.J.E.G. van der Kolk. Drs. J. van Loo heeft paragraaf 3 geschreven. Verder hebben aan het Schoolverlatersinformatiesysteem 1999 meegewerkt dr. J.P. Allen, drs. T.G. Huijgen, drs. G.W.M. Ramaekers en E.M.H.P. Soudant (allen werkzaam bij ROA), alsmede drs. M. van Alphen, drs. H. van Dongen, drs. ing. K.J. Pagrach, ing. J.J. Rutjes en drs. R. Tjemmes (allen werkzaam bij DESAN Marktonderzoek).labour market entry and occupational careers;

Glasslike Arrest in Spinodal Decomposition as a Route to Colloidal Gelation

Colloid-polymer mixtures can undergo spinodal decomposition into colloid-rich and colloid-poor regions. Gelation results when interconnected colloid-rich regions solidify. We show that this occurs when these regions undergo a glass transition, leading to dynamic arrest of the spinodal decomposition. The characteristic length scale of the gel decreases with increasing quench depth, and the nonergodicity parameter exhibits a pronounced dependence on scattering vector. Mode coupling theory gives a good description of the dynamics, provided we use the full static structure as input.Comment: 14 pages, 4 figures; replaced with published versio

Reduced protein diffusion rate by cytoskeleton in vegetative and polarized Dictyostelium cells

Fluorescence recovery after photobleaching measurements with high spatial resolution are performed to elucidate the impact of the actin cytoskeleton on translational mobility of green fluorescent protein (GFP) in aqueous domains of Dictyostelium discoideum amoebae. In vegetative Dictyostelium cells, GFP molecules experience a 3.6-fold reduction of their translational mobility relative to dilute aqueous solutions. In disrupting the actin filamentous network using latrunculin-A, the intact actin cytoskeletal network is shown to contribute an effective viscosity of 1.36 cP, which accounts for 53% of the restrained molecular diffusion of GFP. The remaining 47% of hindered protein motions is ascribed to other mechanical barriers and the viscosity of the cell liquid. A direct correlation between the density of the actin network and its limiting action on protein diffusion is furthermore established from measurements under different osmotic conditions. In highly locomotive polarized cells, the obstructing effect of the actin filamentous network is seen to decline to 0.46 cP in the non-cortical regions of the cell. Our results indicate that the meshwork of actin filaments constitutes the primary mechanical barrier for protein diffusion and that any noticeable reorganization of the network is accompanied by altered intracellular protein mobility

Dual-tip-enhanced ultrafast CARS nanoscopy

Coherent anti-Stokes Raman scattering (CARS) and, in particular, femtosecond adaptive spectroscopic techniques (FAST CARS) have been successfully used for molecular spectroscopy and microscopic imaging. Recent progress in ultrafast nanooptics provides flexibility in generation and control of optical near fields, and holds promise to extend CARS techniques to the nanoscale. In this theoretical study, we demonstrate ultrafast subwavelentgh control of coherent Raman spectra of molecules in the vicinity of a plasmonic nanostructure excited by ultrashort laser pulses. The simulated nanostructure design provides localized excitation sources for CARS by focusing incident laser pulses into subwavelength hot spots via two self-similar nanolens antennas connected by a waveguide. Hot-spot-selective dual-tip-enhanced CARS (2TECARS) nanospectra of DNA nucleobases are obtained by simulating optimized pump, Stokes and probe near fields using tips, laser polarization- and pulse-shaping. This technique may be used to explore ultrafast energy and electron transfer dynamics in real space with nanometre resolution and to develop novel approaches to DNA sequencing.Comment: 11 pages, 6 figure

Water Dynamics at Protein Interfaces: Ultrafast Optical Kerr Effect Study

The behavior of water molecules surrounding a protein can have an important bearing on its structure and function. Consequently, a great deal of attention has been focused on changes in the relaxation dynamics of water when it is located at the protein surface. Here we use the ultrafast optical Kerr effect to study the H-bond structure and dynamics of aqueous solutions of proteins. Measurements are made for three proteins as a function of concentration. We find that the water dynamics in the first solvation layer of the proteins are slowed by up to a factor of 8 in comparison to those in bulk water. The most marked slowdown was observed for the most hydrophilic protein studied, bovine serum albumin, whereas the most hydrophobic protein, trypsin, had a slightly smaller effect. The terahertz Raman spectra of these protein solutions resemble those of pure water up to 5 wt % of protein, above which a new feature appears at 80 cm–1, which is assigned to a bending of the protein amide chain

Spaceflight Activates Lipotoxic Pathways in Mouse Liver

Spaceflight affects numerous organ systems in the body, leading to metabolic dysfunction that may have long-term consequences. Microgravity-induced alterations in liver metabolism, particularly with respect to lipids, remain largely unexplored. Here we utilize a novel systems biology approach, combining metabolomics and transcriptomics with advanced Raman microscopy, to investigate altered hepatic lipid metabolism in mice following short duration spaceflight. Mice flown aboard Space Transportation System -135, the last Shuttle mission, lose weight but redistribute lipids, particularly to the liver. Intriguingly, spaceflight mice lose retinol from lipid droplets. Both mRNA and metabolite changes suggest the retinol loss is linked to activation of PPARα-mediated pathways and potentially to hepatic stellate cell activation, both of which may be coincident with increased bile acids and early signs of liver injury. Although the 13-day flight duration is too short for frank fibrosis to develop, the retinol loss plus changes in markers of extracellular matrix remodeling raise the concern that longer duration exposure to the space environment may result in progressive liver damage, increasing the risk for nonalcoholic fatty liver disease