Investigación en el terreno : un taller para identificar las necesidades de investigación de las comunidades afectadas por la minería a gran escala, Ottawa, 14-16 de abril del 2000; informe del taller

Versión en inglés disponible en la Biblioteca Digital del IDRC: On the ground research : a workshop to identify the research needs of communities affected by large - scale mining, Apr. 14-16, 2000, Ottawa, Canada; workshop repor

A validated numerical model for the growth and resorption of bubbles in magma

The rate and timing of bubble growth in magma is an important control on eruption style, determining whether or not magma fragments to produce an explosive eruption. Bubbles nucleate, grow, shrink, and de-nucleate in magma in response to changes in pressure and temperature, and these changes may be recorded in the spatial distribution and speciation of water 'frozen into' the glass in eruptive products. Accurate modelling of growth and resorption is therefore essential both for forward modelling of eruptive processes, and for inverse modelling to reconstruct pre-eruptive history. We present the first experimentally-validated numerical model for bubble growth and resorption in magma. The model includes the kinetics of speciation, allows for arbitrary temperature and pressure pathways, and accounts for the impact of spatial variations in water content on diffusivity and viscosity. We validate the model against three sets of data. (1) Continuous vesicularity-time data collected using optical dilatometry and in-situ synchrotron-source x-ray tomography of natural and synthetic magma during thermally-induced vesiculation and resorption at magmatic temperatures and ambient pressure. This represents approximately isobaric bubble growth and resorption under disequilibrium conditions. (2) Final vesicularity data from decompression experiments at magmatic temperatures and pressures. This represents isothermal, decompression-driven bubble growth from equilibrium to strongly disequilibrium conditions. (3) Speciation data from diffusion-couple experiments on synthetic haplogranites at magmatic temperatures and pressures. The numerical model closely reproduces all experimental data, providing validation against equilibrium and disequilibrium bubble growth/resorption and speciation scenarios. The validated model can be used to predict the growth and resorption of bubbles, and associated changes in magma properties, for arbitrary eruption pathways. It can also be used to reconstruct pressure-temperature-time pathways from textures and volatile contents of eruptive products. This will open up new ways of accessing the dynamics of magma ascent and eruption in unobserved volcanic eruptions

Enhanced Sarcolemmal FAT/CD36 Content and Triacylglycerol Storage in Cardiac Myocytes From Obese Zucker Rats

International audienc

Cancer-ID:Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1μm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic

Requirement for distinct vesicle-associated membrane proteins in insulin- and AMP-activated protein kinase (AMPK)-induced translocation of GLUT4 and CD36 in cultured cardiomyocytes

Upon stimulation of insulin signalling or contraction-induced AMP-activated protein kinase (AMPK) activation, the glucose transporter GLUT4 and the long-chain fatty acid (LCFA) transporter CD36 similarly translocate from intracellular compartments to the plasma membrane of cardiomyocytes to increase uptake of glucose and LCFA, respectively. This similarity in regulation of GLUT4 traffic and CD36 traffic suggests that the same families of trafficking proteins, including vesicle-associated membrane proteins (VAMPs), are involved in both processes. While several VAMPs have been implicated in GLUT4 traffic, nothing is known about the putative function of VAMPs in CD36 traffic. Therefore, we compared the involvement of the myocardially produced VAMP isoforms in insulin- or contraction-induced GLUT4 and CD36 translocation. Five VAMP isoforms were silenced in HL-1 cardiomyocytes. The cells were treated with insulin or the contraction-like AMPK activator oligomycin or were electrically stimulated to contract. Subsequently, GLUT4 and CD36 translocation as well as substrate uptake were measured. Three VAMPs were demonstrated to be necessary for both GLUT4 and CD36 translocation, either specifically in insulin-treated cells (VAMP2, VAMP5) or in oligomycin/contraction-treated cells (VAMP3). In addition, there are VAMPs specifically involved in either GLUT4 traffic (VAMP7 mediates basal GLUT4 retention) or CD36 traffic (VAMP4 mediates insulin- and oligomycin/contraction-induced CD36 translocation). The involvement of distinct VAMP isoforms in both GLUT4 and CD36 translocation indicates that CD36 translocation, just like GLUT4 translocation, is a vesicle-mediated process dependent on soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex formation. The ability of other VAMPs to discriminate between GLUT4 and CD36 translocation allows the notion that myocardial substrate preference can be modulated by these VAMPs

How much choice is there in housing choice vouchers? Neighborhood risk and free market rental housing accessibility for active drug users in Hartford, Connecticut

<p>Abstract</p> <p>Background</p> <p>Since the mid-1970s, the dominant model for U.S. federal housing policy has shifted from unit-based programs to tenant based vouchers and certificates, intended to allow recipients a choice in their housing and neighborhoods. Surprisingly little research has examined the question of where those with Section 8 housing vouchers are able to live, but some research suggests that voucher holders are more likely to reside in distressed neighborhoods than unsubsidized renter households. Further, federal housing policy has limited drug users' access to housing subsidies. In turn, neighborhood disorder has been associated with higher levels of injection drug risk behaviors, and higher drug-related mortality. This paper explores rental accessibility and neighborhood characteristics of advertised rental housing in Hartford CT.</p> <p>Methods</p> <p>Brief telephone interviews were conducted with landlords or management companies with units to rent in Hartford to explore housing accessibility measured as initial move in costs, credit and criminal background checks, and whether rental subsidies were accepted. These data were supplemented with in-depth interviews with landlords, shelter staff and active users of heroin, crack or cocaine. Apartments for rent were geocoded and mapped using <b>ArcGIS</b>. We used location quotients to identify areas where low-income rental housing is concentrated. Finally, we mapped apartments in relation to drug and violent arrest rates in each neighborhood.</p> <p>Results</p> <p>High security deposits, criminal background and credit checks limit housing accessibility even for drug users receiving vouchers. While most landlords or management companies accepted housing subsidies, several did not. Voucher units are concentrated in neighborhoods with high poverty neighborhoods. Landlords reported little incentive to accept rental subsidies in neighborhoods with low crime rates, but appreciated the guarantee provided by Section 8 in high crime neighborhoods that were less likely to attract applicants with good jobs and credit.</p> <p>Conclusion</p> <p>Housing vouchers in themselves do not greatly improve recipients' choice of neighborhood and voucher units are concentrated in the most distressed neighborhoods. Policy changes are needed to increase landlords' incentives to accept housing subsidies. Interventions to improve neighborhood conditions are needed to improve the probability of success for those recovering from drug addictions.</p

A generalized invariant imbedding equation II

Research into fetal development and medicin