What one experiences today as atmosphere is a transient snapshot and result of its evolutionary history. Much of the development and present status was explained based both on scientific knowledge, and combined with established facts, even speculation. The planet Earth was formed around 4600 million years ago by the gravitational accretion of relatively small rocks and dust, within the solar ne...

in recent years noise has been well known as an environmental pollution. particularly its effects will be more serious in some environments including hospitals which patients need a calm and peaceful condition. this study aims to evaluate hospitals noise pollution level. this study is a cross-sectional study. noise measurements were made in all hospital wards in a workday and weekend from 8 to ...

water quality trading is a new approach in pollution control which satisfies water quality standards suggesting minimum cost solutions. this method uses tradable discharge permits based on pollution transfer coefficient in a river. this paper tries to establish a water quality trading program in a river basin according to transfer coefficients between pollution sources and evaluate cost effecti...

RESUMO – Quantificação de Poluição do Ar – A atividade industrial é uma das principais causas da poluição do ar urbano. Várias técnicas são utilizadas para monitorar e analisar os agentes poluidores. A técnica de modelamento de receptor é uma delas. A aplicação de programação linear para a quantificação de fontes poluidoras do ar, utilizando o modelamento de receptor, é apresentada neste artigo...

Solomon Benatar In response to the case study by Kass et al. on research ethics committees (RECs) in Africa [1], the following additional information is provided about capacity building for research ethics in South Africa. South Africa has two programs funded by the Fogarty International Center: the International Research Ethics Network for Southern Africa (IRENSA; see http:⁄⁄www.irensa. org) b...