Studi Proses Ekstraksi Mineral Tembaga Menggunakan Gelombang Mikro Dengan Variasi Waktu Radiasi Dan Jenis Reduktor

Sebuah material tembaga yang berjenis chalcopyrite dengan metode ekstraksi telah selesai dilakukan. Bahan dasar A yang digunakan adalah chalcopyrite(CuFeS2 ), silika (SiO2) serta arang dan briket kokas sebagai reduktor yang disinari gelombang mikro dengan variasi waktu radiasi 40 menit, 50 menit dan 60 menit. Penelitian ini dimaksudkan untuk mengetahui mekanisme proses ekstraksi mineral tembaga dengan penggunaan gelombang mikro dan untuk mengetahui waktu radiasi dan jenis reduktor yang optimal terhadap peningkatan kandungan tembaga. Studi dilakukan dengan pengujian XRF, SEM, serta XRD. Hasil penelitian menunjukkan bahwa peningkatan kandungan Cu yang optimal didapat pada waktu radiasi selama 60 menit dengan menggunakan reduktor arang. Secara umum, semakin lama waktu radiasi dan semakin rendah nilai kalori dari reduktor maka % Wt Cu yang didapat semakin tinggi dengan nilai maksimum 3,53 Cal/gr. Hasil analisis XRD menunjukkan pada semua variasi waktu radiasi senyawa yang terbentuk adalah Cu dan CuS2 yang menandakan bahwa proses ekstraksi berjalan belum begitu sempurna.. Kata Kunci—chalcopyrite, ekstraksi, reduktor,gelombang mikro

Stability and electronic structure of M-DNA: Role of metal position

We investigate, by first-principles density-functional calculations, fragments and periodic helices of CG- and AT-DNA, modified by incorporation of Zn2+ cations. We study the relative stability of different binding sites for the metal ions as well as different methods of charge neutralization. We find that binding the Zn cation to the N(7) atom of guanine or adenine leads always to lower energies than substitution of an imino proton between two H-bonded bases. Also, neutralizing with OH- groups bonded to Zn2 + is more stable than removing protons from the phosphate groups. Contrarily to common wisdom, we find that planarity of the base pairs is not an essential factor of stability, and that nonplanar base pairs can also be stacked effectively. Finally, we find that the most stable CG and AT helices, with Zn2+ bonded to N(7) atoms and neutralized by OH- ions, have wide band gaps of more than 2 eV, and we conclude that they are poor candidates for electronic conductionThis work has been supported by Brazilian agencies: Fapemig, CNPq, and Ministerio da Ciencia e Tecnologia; by Grants FIS2009-12712, MAT2010-20843-C02-01, and CSD2007-00050 of the Spanish Ministry of Science and Innovation; and by European Grant EU(FP6-029192

Intrastromal corneal ring segments: how successful is the surgical treatment of keratoconus?

This review evaluates the outcomes of intrastromal corneal ring segment (ICRS) implantation for the treatment of keratoconus considering a new grading system based on the preoperative visual impairment of the patient. Additionally, a five-year follow-up analysis of patients with stable and progressive keratoconus is performed in order to assess the long term stability of the surgical procedure. Corrected distance visual acuity decreased statistically significantly in patients with mild keratoconus (P < 0.01) but statistically significantly increased in all other grades (P < 0.05). The improvement in visual acuity and the decrease of keratometric and aberrometric values were stable throughout a long period of time in patients with stable keratoconus. In patients with progressive form keratoconus, a significant improvement was found immediately after the procedure, however clinically relevant regression greater than 3 D was observed at the end of the follow up period

Balanced Scorecard as a management model in the waste sector

All Organizations recognize that internal methodologies and frameworks are very important to have a thorough knowledge of their potential, simultaneous increase competitiveness and, correspondingly, enhance and optimize the performance of their service. Waste management is a challenge of modern society, and there is awareness that responsibility of waste management should be shared by all community, to cooperate and ensure a sustainable development with the best principles and best management practices. It is a citizenship issue, where citizens contribute adopting preventative behaviours in the production of waste, as well as practices that facilitate waste recycling, reuse and recovery, which contribute to reduce the waste life cycle. This concern and the service improvement involve the minimization of the environmental impacts, the conservation of the natural resources, the reduction of pollutant emissions, as well as the design of the solutions for the collection, transfer and transport, treatment and waste final deposition, and the allocation of human and financial resources. The need for a sustainable management of resources has led to the design and development of management models in waste systems to assess in what extent the various tasks or activities are (or are not) carried out in accordance with the objectives established in advance and the efforts, decisions and operational actions developed by organisations to improve the quality of its work. Thus, given the problems and requirements of the waste sector, it is necessary to outline and plan sustainable strategies for the management system. Therefore, the objective of the present work is the application and study of key concepts related to design and implementation of a management model, the Balanced Scorecard (BSC). This is a management method based on critical success factors, which propose is to translate through a systemic approach, the mission and strategy of Organizations (private or public / nonprofit) in operational objectives, arranged into perspectives interconnected in a cause-effect relation. It connects the strategic objectives to measurable measures (performance indicators) that indicate the success or failure of the adopted strategy, contributing to a review. The BSC is a very useful and simple management tool, which perfectly suits the needs of the waste sector. It works as a measurement and management system, and a basis for the strategy communication to all elements of the system, and through a joint analysis, demonstrates of the importance of all stakeholders to the overall management, encouraging their involvement and motivation

Assisted Community-Led Systematic Land Tenure Regularization

Systematic land cadastre is still an expensive and time-consuming endeavour in Mozambique. Government adopted the approach of systematic land cadastre, launching the "Terra Segura" Programme, to cover 4 thousand communities and 5 million rural parcels, out of an estimated total universe of circa 12 million parcels and plots. The initial exercises to attend this massive registration utilized traditional methods of land tenure regularization, resulting in being either too expensive or time-consuming initiatives, with serious problems of data quality. New approaches were designed and tested to create an effective sustainable cadastre, proposing an holistic approach to register the land. However, because strong evidence must be presented with regards to this holistic approach, there is a need to scale up the tests. The end goal of this scaling up exercise is to learn and disseminate lessons in local capacity development and improve the methodology and tools of the Terra Segura programme. Key Words

O olhar enternecido: contribuições para a leitura da obra poética de Jorge Sousa Braga

Dissertação de mest., Promoção e Mediação de Leitura, Faculdade de Ciências Humanas e Sociais, Univ. do Algarve, 2011O presente trabalho constitui uma leitura da obra poética de Jorge Sousa Braga, na qual são analisadas as antologias de potencial receção infantil, assim como a coletânea que reúne os poemas destinados ao leitor adulto, procurando desvendar-se as características marcantes da sua escrita poética, nomeadamente os traços ideotemáticos e os processos retóricos que a percorrem e a tornam singular. A relação com a natureza e a ciência, a poética da contenção e o aproveitamento semântico-estilístico da intertextualidade, da ironia e do humor são aspetos estudados nesta dissertação

Avaliação do Desempenho do Teste de Rastreio de Alergia Alimentar FP5® (DPC-Amerlab)

Introdução: A utilização dos testes de rastreio para detecção de IgE específica sérica para diversos alergénios tem sido discutida, sendo invariavelmente aceite a sua utilidade no que diz respeito aos aeroalergénios, não tendo sido ainda suficientemente estabelecida a eficiência dos testes correspondentes destinados à detecção de alergénios alimentares, como acontece com o FP5® da Diagnostic Products Corporation (contendo mistura de clara de ovo, leite, bacalhau, trigo,soja e amendoim). Objectivo: Avaliar o desempenho do teste FP5®, determinando a sua sensibilidade, especificidade e comparação com os métodos de detecção das correspondentes IgE específicas isoladas. Material e métodos: Foi incluída uma amostra aleatória de 54 soros de crianças com alergia alimentar e com determinações de IgE específica positivas para um ou mais dos alimentos testados pelo FP5® - grupo de estudo; foi seleccionado um grupo controlo de 27 amostras de sangue de crianças sem alergia alimentar e em que a determinação de IgE específica para todos os alimentos incluídos no painel em estudo foi negativa. Em ambos os grupos foi efectuada determinação da concentração de IgE específica sérica (kU/l) para FP5®, F1 (clara de ovo), F2 (leite), F3 (bacalhau), F4 (trigo), F13 (soja) e F14 (amendoim), pelo método de quimioluminiscência Immulite®2000. O valor de cut-off considerado foi de 0,35 kU/l. Resultados: Foram testados 81 soros encontrando-se os seguintes parâmetros do teste: sensibilidade=88,9%, especificidade =100%, valor predictivo positivo=100%, valor predictivo negativo=81,8%,eficiência=92,6%. Considerando cada uma das IgE específicas do painel, verificou-se que em todos os soros com determinações positivas para F3, F4, F13 e F14, o FP5® foi também positivo; no caso dos alergénios F1 e F2, observaram-se 3 resultados discrepantes para cada (falsos-negativos). Correlacionando os resultados do FP5® (quantitativos) e o somatório das correspondentes IgE específicas, obtivemos um coeficiente de 0.99, p<0.001. Conclusões: De acordo com os resultados obtidos, verifica-se que o teste de rastreio estudado apresenta boa sensibilidade e eficiência, eexcelente especificidade. De salientar ainda que se trata de um teste que envolve significativa rentabilização de recursos económicos, quando comparado com a determinação das correspondentes IgE específicas isoladas. Concluímos tratar-se de um método cuja utilidade poderá ser considerada na abordagem inicial do doente com suspeita de alergia alimentar IgE mediada, no âmbito dos cuidados de saúde primários