The Hertz Corporation

About: The Hertz Corporation is a based out in . It is known for research contribution in the topics: Population & Soil water. The organization has 9562 authors who have published 11044 publications receiving 447929 citations. The organization is also known as: Hertz Rental Car & Hertz Rent-a-Car.

The role of soil microorganisms in soil organic matter conservation in the tropics

Abstract: Soil is a large sink for organic carbon within the terrestrial biosphere. Practices which cause a decline in soil organic matter cause CO2 release, in addition to damaging soil resilience and, often, agricultural productivity. The soil micro-organisms (collectively the soil microbial biomass) are the agents of transformation of soil organic matter, nutrients and of most key soil processes. Their activities are much influenced by soil physico-chemical and ecological interactions. This paper addresses two key issues. Firstly, ways of managing, and the extent to which it is possible to manage, soil biological functions. Secondly, the methodologies currently available for studying soil micro-organisms, and the functions they mediate, are discussed. It is concluded that, as the world population develops in this new millennium, there will be an increased dependence upon biological processes in soil to provide adequate crop nutrition for the majority of the world’s farmers. Although a major increase in the use of artificial fertilisers will be necessary on a global scale, this will not be an option for large numbers of farmers due to their poverty. Instead they will rely on recycling of nutrients from animal and vegetable composts and urban wastes, and biological cycling from nitrogen fixation and mycorrhizae. The challenge is to select the most appropriate topics for further research. Not all aspects are likely to lead to significantly improved agricultural productivity, or sustainability within the foreseeable future.

The use of photoresist as a holographic recording medium.

Abstract: A technique is described for recording holograms and forming diffraction gratings in Shipley AZ1350 photoresist using the 4579-A output from an argon laser. A pre-exposure technique is described that not only reduces exposure times but increases the signal-to-noise ratio of the image. It is also shown that the effects of the variable characteristic of the resist can be alleviated by monitoring diffraction efficiency during development.

An application of maximum likelihood and generalized estimating equations to the analysis of ordinal data from a longitudinal study with cases missing at random.

Abstract: Data are analysed from a longitudinal psychiatric study in which there are no dropouts that do not occur completely at random A marginal proportional odds model is fitted that relates the response (severity of side effects) to various covariates Two methods of estimation are used: generalized estimating equations (GEE) and maximum likelihood (ML) Both the complete set of data and the data from only those subjects completing the study are analysed For the completers-only data, the GEE and ML analyses produce very similar results These results differ considerably from those obtained from the analyses of the full data set There are also marked differences between the results obtained from the GEE and ML analysis of the full data set The occurrence of such differences is consistent with the presence of a non-completely-random dropout process and it can be concluded in this example that both the analyses of the completers only and the GEE analysis of the full data set produce misleading conclusions about the relationships between the response and covariates