the aim of this investigation was to assess the effect of different antioxidants on the motility andmembrane integrity of the ram semen during storage at 5ºc for 0, 12, 24, 48 and 72 hrs after collection anddilution. a total of 57 ejaculates from 12 bakhtiary rams was collected by artificial vagina and were extended1 : 3 with egg yolk-citrate buffer, which was containing one of the following an...

in this study, the relationship between components of knowledge management on the basis of m. mc olrvy model and social capital has been studied, statistical population consisted of employees of ministry of energy, who were selected among employees of hamedan regional power and were 420 subjects. research tool is a questionnaire and spss statistical software is used for data analysis and struct...

Human population growth and the consequent increase in use of natural resources place enormous stress on ecosystems. Road building, urbanization and agriculture are among the main human activities that break up natural areas, often with disastrous consequences for wildlife. Concern about threats to biodiversity is reflected in the continuous increase in the number and size of protected areas wo...

Systematic conservation planning research has focused on designing systems of conservation areas that efficiently protect a comprehensive and representative set of species and habitats. Recently, there has been an emphasis on improving the adequacy of conservation area design to promote the persistence and future generation of biodiversity. Few studies have explored incorporating ecological and...

www.sciencemag.org (this information is current as of February 2, 2009 ): The following resources related to this article are available online at http://www.sciencemag.org/cgi/content/full/323/5910/133 version of this article at: including high-resolution figures, can be found in the online Updated information and services, http://www.sciencemag.org/cgi/content/full/1162986/DC1 can be found at:...

Introduction The protection of biodiversity has become an important national and international issue within the past decade (see Noss and Cooperrider 1994 for a discussion of the reasons, which range from intrinsic to aesthetic). Canada, along with over 150 other countries, ratified the 1992 Convention on Biological Diversity (CBD 1992), and is obliged to implement the provisions of the convent...

Until recently, managing water quality in a watershed was widely viewed as a matter of installing (and operating) an infrastructure to deal with pollution from industrial and domestic urban sewage. Data on discharges and pollutant loads from a population equivalent, generated or collected from within a government bureaucracy, were used by professional engineers to specify the level of infrastru...

This study evaluated integrative river ecosystem health using stressor-based models of physical habitat health, chemical water health, and biological health of fish and identified multiple-stressor indicators influencing the ecosystem health. Integrated health responses (IHRs), based on star-plot approach, were calculated from qualitative habitat evaluation index (QHEI), nutrient pollution inde...

Conservation planning aims to protect biodiversity by sustainng the natural physical, chemical, and biological processes within representative ecosystems. Often data to measure these components are inadequate or unavailable. The impact of human activities on ecosystem processes complicates integrity assessments and might alter ecosystem organization at multiple spatial scales. Freshwater conser...