Ecological matters

Adhesion, Cell-Cell Recognition, and Cell 1908 G. Ecological Matters (Author s Personal... 

In Mexico City, several air quality parameters are measured continuously by an Automated Monitoring Network operated by the Under Secretariat of Ecology. Carbon monoxide, particulate matter, sulfur dioxide, nitrogen oxide, and ozone are the contaminants exceeding Air Quality Standards. Emissions produced by 2.7 million vehicles and 35,000 commercial and industrial outfits are not easily dispersed in a Valley located at 2240 m and surrounded by two mountain chains which hinder air circulation. An Integral Program, recently established to alleviate pollution, is briefly described. 

Recurrent is the lack of adequate techniques to assess carbon flows through the plants and microbes into soil organic matter (151). Most important is the development of techniques and protocols to separate rhizosphere from nonrhizosphere soil as well as possibly to facilitate analyses of soil carbon dynamics. The use of carbon isotopes, and, where possible, application of double labeling with C and C, seems inevitable in order to separate the contribution of different substrates to the formation of the soil organic matter pool and to get to an understanding of the ecological advantage of exudates and rhizodeposits. 

D. A. Wedin, L. L. Tieszen, B. Dewey, and J. Pastor, Carbon isotope dynamics during grass decomposition and soil organic matter formation. Ecology 76 1383 (1995). 

The behavior of technetium in soils is important from an ecological viewpoint, but is quite complicated and depends on many factors. Stalmans et al. [27] stated that it is ruled by a combination of chemical, physicochemical and biological factors and understanding of it is needed on two main accounts bioavailability and geochemical mobility . They also noticed that organic matter in soils and sediments play a significant role as a geochemical sink for technetium. 

Abstract The characterization of toxicological impact of chemicals and mixtures from environmental matrices is a critical point in the assessment of adverse effects induced in human and ecological targets. In fact, the toxicity of most of the environmental mixtures is still under investigation due to the possibility of synergic or antagonistic effects of the components. Moreover, in some cases, the toxicity of identified chemicals is not already well known and it could be an additional matter of concern. 

Lloyd concurs and adds the patient s social entirety as well, citing a series of studies that show that ecological factors also matter, most surprisingly the income gradient of a society. What matters is not simply the difference between the richest and poorest people in some absolute sense, but the relative difference in their own society. People living in a relatively poor society can lead healthier lives than people living in a richer society if the difference between the richest and the poorest in their society is less. What really matters is how much poorer poor people are in a society relative to the richest people. However, Lloyd s later appeal to data drawn from primate studies might lead some to cry reductionism . The human species is unique. No inferences can be made from other species, even primate species, to us. 

The major function of cutin is to serve as the structural component of the outer barrier of plants. As the major component of the cuticle it plays a major role in the interaction of the plant with its environment. Development of the cuticle is thought to be responsible for the ability of plants to move onto land where the cuticle limits diffusion of moisture and thus prevents desiccation [141]. The plant cuticle controls the exchange of matter between leaf and atmosphere. The transport properties of the cuticle strongly influences the loss of water and solutes from the leaf interior as well as uptake of nonvolatile chemicals from the atmosphere to the leaf surface. In the absence of stomata the cuticle controls gas exchange. The cuticle as a transport-limiting barrier is important in its physiological and ecological functions. The diffusion across plant cuticle follows basic laws of passive diffusion across lipophylic membranes [142]. Isolated cuticular membranes have been used to study this permeability and the results obtained appear to be valid... 

---