Evaluation of the Concept that Pumahuasi Veins Indicate a Potential for the Existence of Underlying Undiscovered Sedex Deposits, Northern Argentina

Fil: Sangster, Alan L. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Sangster, Donald F. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.We have been asked by SEGEMAR to comment on the possibility that the Pumahuasi veins (Figure 1) may be mobilized Sedex mineralization and that their presence indicates an exploration potential for Sedex base metal deposits, similar to the Aguilar deposit, in the Pumahuasi area

Report on a Reconnaissance Visit to Examine Mineralization in the Cordillera Fueguina, Tierra del Fuego, Argentina

Fil: Marquéz, M. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.Fil: Sangster, D.F. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.This report describes observations made of metallic mineralization in the Cordillera Fueguina, Tierra del Fuego province. These activities relied on the collaboration and logistic support of Yamana Resources loe. who, through the cooperation of resident geologist Ken Gibson, allowed the authors access to ali information obtained during exploration in the last three years. The work during the field trip between FebruarylO -13, 1998 consisted of: A) the examination of mineralized drill core intersections from the Arroyo Rojo and Sargent prospects and a review of geological reports and maps; B) geological reconnaissance of the Beatrice mine and Lapataia areas, and C) reconnaissance of the geology and mineralized areas ofthe Monte Olivia and Río Hambre. Toe most important objective was to define the mineralization characteristics and, if possible, to suggest a preliminary genetic model

Resident and family perceptions of the nurse practitioner role in long term care settings: a qualitative descriptive study

BackgroundResearch evidence supports the positive impact on resident outcomes of nurse practitioners (NPs) working in long term care (LTC) homes. There are few studies that report the perceptions of residents and family members about the role of the NP in these settings. The purpose of this study was to explore the perceptions of residents and family members regarding the role of the NP in LTC homes.MethodsThe study applied a qualitative descriptive approach. In-depth individual and focus group interviews were conducted with 35 residents and family members from four LTC settings that employed a NP. Conventional content analysis was used to identify themes and sub-themes.ResultsTwo major themes were identified: NPs were seen as providing resident and family-centred care and as providing enhanced quality of care. NPs established caring relationships with residents and families, providing both informational and emotional support, as well as facilitating their participation in decision making. Residents and families perceived the NP as improving availability and timeliness of care and helping to prevent unnecessary hospitalization.ConclusionsThe perceptions of residents and family members of the NP role in LTC are consistent with the concepts of person-centred and relationship-centred care. The relationships NPs develop with residents and families are a central means through which enhanced quality of care occurs. Given the limited use of NPs in LTC settings, there is an opportunity for health care policy and decision makers to address service inadequacies through strategic deployment of NPs in LTC settings. NPs can use their expert knowledge and skill to assist residents and families to make informed choices regarding their health care and maintain a positive care experience

Thermochemical experiments on certain iron minerals.

The writer takes this opportunity to acknowledge the encouragement and guidance received from Dr. V.A. Saull under whose direction these experiments were carried out. The interest shown and suggestions offered by the writer is colleagues are greatly appreciated. Financial assistance was received through Research Grant number 26-53 awarded to Dr. Saull by the Geological Survey of Canada

The effect of aqueous-phase solubility on free-radical exit from latex particles

The technique of γ-radiolysis relaxation is used to study the rate coefficient for exit (desorption) of free radicals from styrene latex particles at 30 °C in the presence of methanol (which serves to increase the solubility of monomer in the aqueous phase). The observed exit rate coefficient is directly proportional to the solubility of monomer in the aqueous phase, until the latter becomes so high that the transfer-dominated limit is reached. These results are in quantitative agreement with the Nomura transfer/diffusion theory for exit

Termination-rate coefficients in methyl methacrylate polymerizations

It is shown that, by observing the kinetics of the seeded emulsion polymerization of methyl methacrylate with and without added chain-transfer agent, and using gamma -radiolytic initiation, it is possible to examine separately the effects of the length of the growing chain and of the weight fraction of polymer on the termination rate coefficient. Studies using this technique confirm predictions that chain entanglement causes translational diffusion to be the rate-determining termination event for growing chains of lower molecular weight, while the rate-determining termination event for growing chains of higher molecular weight is 'residual,' the annihilation encounter being caused by excess chain end mobility of two growing chains in a viscous medium. The data show unambiguously that free-volume theories which do not incorporate the molecular weight of the growing chain are inapplicable to this system

Styrene emulsion polymerization: Particle-size distributions

Data are presented on the time evolution of particle-size distributions (PSDs) in seeded and ab initio styrene emulsion polymerization systems. Initiation was by chemical reagent (potassium persulfate) or γ-radiation. The unswollen PSDs at various times during interval II of the polymerization were obtained by direct measurement of calibrated electron micrographs. Experimental results were fitted with the equations that describe the time evolution of an initial PSD. Analytic solutions to these equations that allow for entry, exit, and propagation of free radicals were obtained. The values of the rate coefficients for these processes used to fit the experimental data were in excellent agreement with those obtained from dilatometric kinetics experiments

Free radical entry in emulsion polymerizations

Measurements of the rate coefficients characterising the entry of free radicals into seed particles in styrene emulsion polymerizations has allowed the rate determining step for entry to be identified. This was found to be the rate of production of oligomeric species in the aqueous phase by monomer addition to the primary free radicals. Once formed the subsequent diffusion of these species to the latex particles (and their incorporation within these particles) is relatively fast, contrary to the assumptions of the previous diffusion controlled theories. The experimental results imply that the entering free radicals contain only two or three monomer units. Thermodynamic considerations show that such species should be both water soluble and surface active. Similar conclusions have been reached for other sparingly water soluble monomers, such as butyl acrylate and butyl methacrylate