989 resultados para gold mine


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Evelyn Mae Levine was born April 11, 1907 and died on February 6, 1957. She was one of the children born to William and Sarah Levine. The scrapbook includes photographs, family memories, negative copies of grade sheets from Coburn Classical Instituteand Emerson College.

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This study is motivated by How [How, J., 2000. The initial and long run performances of mining IPOs in Australia. Aust. J. Manage. 25, 95–118] who examined 100 Australian gold mining initial public offerings (IPOs) from 1979 to 1990 to report an average 119.51% underpricing return by those IPOs. This study updates that analysis by investigating 114 Australian gold mining IPOs from 1994 to 2004 and finds a significantly lower 13.3% average first day return. Options offered to underwriters can in part explain these returns as can the change in either the Gold Index or the All Ordinaries Index from the date of the prospectus to the date of listing.

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In this study, gold nanoparticles were synthesized by electroless recovery of [AuCl4]− from an acidic aqueous solution using nano-structured conducting polymer, polypyrrole nanoparticles, as active surface. The formation of gold nanoparticles was confirmed by TEM, SEM and EDX measurements. The effects of the initial Au(III) concentration on the gold uptake was examined. The recovery capability and gold particle morphology prepared from polypyrrole nanoparticle were compared to that from cast PPy film counterpart.

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Objectives: Individual clinical interviews are typically viewed as the “gold standard” when diagnosing major depressive disorder (MDD) and when examining the validity of self-rated questionnaires. However, this approach may be problematic with older people, who are known to underreport depressive symptomatology. This study examined the effect of including an informant interview on prevalence estimations of MDD in an aged-care sample.

Design: The results of an individual clinical interview for MDD were compared with those obtained when an informant interview was incorporated into the assessment. Results from each diagnostic approach were compared with scores on a self-rated depression instrument.

Setting: Low-level aged-care residential facilities in Melbourne (equivalent to “residential homes,” “homes for the elderly,” or “assisted living facilities” in other countries).

Participants: One hundred and sixty-eight aged-care residents (mean age: 84.68 years; SD: 6.16 years) with normal cognitive functioning.

Measurements: Individual clinical interviews were conducted using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders. This interview was modified for use with staff informants. Self-reported depression was measured using the Geriatric Depression Scale-15 (GDS-15).

Results: The estimated point prevalence of MDD rose from 16% to 22% by including an informant clinical interview in the diagnostic procedure. Overall, 27% of depressed residents failed to disclose symptoms in the clinical interview. The concordance of the GDS-15 with a diagnosis of MDD was substantially lower when an informant source was included in the diagnostic procedure.

Conclusion: Individual interviews and self-report questionnaires may be insufficient to detect depression among older adults. This study supports the use of an informant interview as an adjunct when diagnosing MDD among cognitively intact aged-care residents.

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This study explored the interface between the forces of globalization and a given place, at a given time, the Gold Coast during the 1980s. The global economic boom of the 1980s was one in which the role of Japan was particularly important. In less than half a decade capital flows from Japan surged to make it the world's largest investor. Locations in the Pacific Basin were favoured destinations for Japanese investment, one of the most significant was the Gold Coast. Japanese capital and tourism helped transform its urban area from a national resort to an international tourist destination and resort centre, The surge of capital arriving to the Gold Coast was a function of economic conditions in Japan, as was its steep reduction after November 1989, Thus the Gold Coast became integrated into global capital flows and so dependent on decisions made in Tokyo, one of the main financial centres of the world. However this study has also sought to explore a more complex reality; namely, that this place also became the interface of complex cultural forces and perceptions. The wealth of the Japanese investors on the Gold Coast enabled them to realize their dream of developing projects in the most fashionable global styles. These styles were essentially Western, and it was onto these that their Japanese owners ascribed their own meanings; meanings that reflected the cultural baggage that they had brought from Japan, and through which were filtered the economic and environmental realities of the Gold Coast. The Gold Coast as locality also included residents. Hence it became an interface between two different groups of people, the Japanese and the strongly Anglo-Celtic local community. Some in the local community perceived the Japanese presence as a threat to their perception of the Gold Coast, in fact, a threat to their perception of Australia's national identity. A campaign based on the politics of memory of the Japanese developed on the Gold Coast. Within weeks it became a national debate in which isolationalist, if not xenophobic traditionalists, concentrated on the Gold Coast challenged the economic rationalism and multicultural tolerance of the self-interested and ideologically convinced advocates of globalization. Governments at all levels sought to arbitrate, to legitimize standpoints, but more often than not were seen to move into positions of ineffectual flexibility. The forces of globalization on the Gold Coast were catalysts for change that in turn provoked local opposition which rapidly became a debate about national identity and direction. It is in the exploration of the complex and contradictory economic, cultural and political forces engendered by globalization that this study has sought to make a distinctive contribution.

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The Pieman River catchment has seen continuous mining of economic deposits of gold, silver, lead, copper, zinc and tin since the 1870’s. Tributaries of this river which receive mining effluent, either directly or from acid mine drainage (AMID), have total metal concentrations considerably above background levels and are of regulatory concern. The lower Pieman River is however classified as a State Reserve in which recreational fishing and tourism are the major activities. It is therefore important that water entering the lower Pieman River from upstream hydroelectric impoundments is of high quality. Metals in natural waters exist in a variety of dissolved, colloidal and particulate forms. The bioavailability and hence toxicity of heavy metal pollutants is very dependant on their physico form. Knowledge of the speciation of a metal in natural aquatic environments is therefore necessary for understanding its geochemical behaviour and biological availability. Complexation of metal ions by natural ligands in aquatic systems is believed to play a significant role in controlling their chemical speciation. This study has investigated temporal and spatial variation in complexation of metal ions in the Pieman River. The influence of pH, temperature, organic matter, salinity, ionic strength and time has been investigated in a series of field studies and in laboratory-based experiments which simulated natural and anthropogenic disturbances. Labile metals were measured using two techniques in various freshwater and estuarine environments. Diffusive gradients in thin-films (DGT) allowed in situ measurement of solution speciation whilst differential pulse anodic stripping voltammetry (DPASV) was used to measure labile metal species in water samples collected from the catchment. Organic complexation was found to be a significant regulating mechanism for copper speciation and the copper-binding ligand concentration usually exceeded the total copper concentration in the river water. Complexation was highly dependent on pH and at the river-seawater interface was also regulated by salinity, probably as a result of competitive complexation by major ions in seawater (eg. Ca 2+ ions). Zinc complexation was also evident, however total zinc concentrations in the water column often far exceeded the potential binding capacity of available ligands. In addition to organic complexation, Zn speciation may also be associated with adsorption by flocculated or resuspended colloidal Mn and/or Fe oxyhydroxides. Metal ion complexation and hence speciation was found to be highly variable within the Pieman River catchment. This presents major difficulties for environmental managers, as it is therefore not possible to make catchment-wide assumptions about the bioavailability of these metals. These results emphasise the importance of site-specific sampling protocols and speciation testing, ideally incorporating continuous, in situ monitoring.

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We present a facile and effective method for controlling the surface hydrophobicity of polyimide films from sticky to superhydrophobic properties by tailoring their topographies. Nanostructured silver layers were produced on polyimide films by treatment with aqueous KOH and AgNO3, followed by thermal treatment at 200 degrees C or higher temperatures. Further modification of the gold-coated silver layers with n-dodecanethiol led to hydrophobic surfaces. Different morphologies of the silver layers at the micro- and nano-meter scales, which result in the variety of hydrophobicity, can be tailored by controlling the thermal treatment temperature. Surfaces prepared at 320 degrees C showed a sticky property that water drops did not slide off even when the sample was held upside down. Superhydrophobic surfaces were obtained when the temperature was above 340 degrees C. A remarkable superhydrophobicity, as evidenced by a very large water contact angle of 162 degrees and a very small sliding angle of 7 degrees, was achieved by heating the modified polyimide films at 360 degrees C. This is also the first example for superhydrophobic modification of polyimide films.

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Rehabilitation of Alcoa's Anglesea open cut brown coal mine to a healthy lake has many environmental challenges. The study of regional acid drainage, limnology of Wenslydale Coal Mine Lake and passive bioremediation of acid mine water has shown that a healthy lake can be created.