Discrimination of fish oil and mineral oil slicks on sea water

Fish oil and mineral oil slicks on sea water can be discriminated by their different spreading characteristics and by their reflectivities and color variations over a range of wavelengths. Reflectivities of oil and oil films are determined using a duel beam reflectance apparatus

Elemental and isotopic geochemistry of kimberlites from the Lac de Gras field, northwest territories, Canada.

Detailed major/trace element and high-precision Hf-Nd-Sr isotope data has been acquired for 86 samples of kimberlites from the recently discovered Lac de Gras kimberlite field in the Northwest Territories, Canada, plus 23 samples from other Canadian kimberlite occurrences. This constitutes the most comprehensive geochemical database available for kimberlites at the present time, and allows detailed comparisons to be made with the well-documented kimberlites of the Kaapvaal craton, southern Africa. Major and trace element data shows that some Lac de Gras kimberlites have interacted extensively with continental crust, whereas others are minimally contaminated with crust but have physically incorporated large quantities (˃30%) of lithospheric mantle peridotite. Fresh, minimally-contaminated kimberlites from Lac de Gras have both elemental and isotopic characteristics that are transitional relative to those typical of southern African Group I and II kimberlites. The Hf-Nd isotope variations of these samples also define a linear array that strongly suggests mixing of two or more components/reservoirs within the mantle. Isotopic mixing models and mass balance considerations constrain the most likely candidate components/reservoirs to be depleted sub-continental lithospheric mantle and a component with an isotopically-enriched, negative ΔɛHf signature that is derived from beneath the lithosphere. Such a component has previously been identified in southern African kimberlites, indicating that it is globally extensive within the mantle. Its resfriction to magmas generated at great depths, and its unusual Hf isotope signature also suggest that it may reside in isolation at some mantle boundary layer. Ancient oceanic crust, generated by melting in the presence of garnet and subsequently subducted and stored below the lithosphere, could evolve to negative ΔɛHf compositions. Melts of this material, variably recombined with the depleted, garnet- rich melting residua that constitute the lithosphere, can then account for the Hf-Nd kimberiite isotopic array. Trace element characteristics, such as K and Sr anomalies, are consistent with those of OIB-like magmas derived from within the convecting mantle

Immune responses to BCG immunisation and Mycobacterium tuberculosis infection in non-human primates

The evaluation of new vaccines that are urgently needed against tuberculosis (TB) is hampered by the lack of an immune correlate of protection. One of the main measures of immune function utilised in TB vaccine studies is the assessment of interferon (IFN)-ɣ, as it is known that this cytokine is essential for immunity against infection. The studies conducted in this thesis uses the non-human primate model of TB to address whether two measurements of IFN-ɣ (the frequency of IFN-ɣ secreting cells and the concentration of IFN-ɣ secreted) can be related to survival and thus provide a correlate of protection. The Mycobacterium-specific IFN-ɣ profiles have been assessed in two primate species (rhesus macaques and cynomolgus macaques) following immunisation with BCG, or aerosol infection with Mycobacterium tuberculosis. Additionally, one of the most advanced novel TB vaccines (modified vaccinia virus Ankara expressing antigen 85A; MVA85A) has also been tested in this model. When human clinical trial data (provided by Oxford University) using BCG and BCG with an MVA85A boost were compared with results generated in similarly vaccinated macaques, it was observed that rhesus macaques have kinetically similar IFN-ɣ responses, but at different magnitudes. During a vaccine efficacy study, rhesus macaques were shown to be protected from M. tuberculosis infection by BCG vaccination. This allowed the opportunity for responses in animals protected against disease to be compared with those which were not protected. Although results showed that the capability to secrete larger concentrations of PPD-specific IFN-ɣ early after M. tuberculosis infection correlated with longer survival periods, this was not solely due to prior vaccination. Most of the IFN-ɣ responses during the vaccination periods did not relate to survival after challenge, except peak frequencies of IFN-ɣ secreting cells after BCG vaccination. Therefore, it was concluded that measuring IFN-ɣ alone does not provide the correlate of protection that is presently lacking in TB vaccine research

Brazil's urban land and housing markets: How well are they working?

This paper uses a macro, national-level perspective to assess urban land and housing market outcomes across Brazil. It is based on available empirical data from IBGE, field studies, the Fundação João Pinheiro, and other sources. The paper starts by posing and answering the following questions: What are the characteristics of well-functioning urban land and housing markets? How well are Brazils urban land and housing markets performing relative to other countries? It then proceeds to provide an assessment of urban land and housing market outcomes in Brazilian cities. The paper concludes by exploring a range of opportunities for enhancing urban land and housing market outcomes

Relación entre las estrategias de aprendizaje y la comprensión lectora en alumnos ingresantes de la Facultad de Educación de la UNMSM

La investigación se encuentra contextualizada dentro del campo psicológico de la educación, aborda el tema estrategias de aprendizaje y su relación con la comprensión lectora en estudiantes universitarios iniciales cursando estudios en la Facultad de Educación de la Universidad Nacional Mayor de San Marcos. Es un estudio de tipo básico que corresponde a un diseño no experimental, de corte transversal La hipótesis formulada corresponde a que existe una relación significativa entre las estrategias de aprendizaje y la comprensión lectora en alumnos ingresantes de la Facultad de Educación de la UNMSM, 2005-I. La población de estudio estuvo conformada por 154 estudiantes y la muestra quedó establecida en 98 estudiantes de ambos sexos con una edad promedio de 19 años, matriculados en el primer ciclo de estudios de la carrera profesional de educación. Los instrumentos aplicados fueron el test ACRA Escala de Estrategias de Aprendizaje de Román y Gallego (1994) y el Test de Comprensión de Lectura de Violeta Tapia y Maritza Silva. Los resultados obtenidos dan a conocer la confirmación de la hipótesis planteada en la existencia de relación significativa entre las variables de estudio. En conclusión, la aceptación de la hipótesis nos lleva a la formulación de sugerencias que implican incidir en el alumnado al manejo eficiente de estrategias de aprendizaje e incentivar el desarrollo de la comprensión lectora a niveles acorde a los estudios universitarios.Tesi