Emissions from heated indoor dust

Settled indoor dust was collected from a university building, and the fine fraction was heated in the temperature range of 50-250 degrees C. Emissions of compounds were analysed and identified in a system consisting of a thermal desorption unit coupled to a gas chromatograph-mass spectrometer (GC-MS). The heating took place in both an oxidative (air) and an inert (He) atmosphere. The results indicate that oxidation of adsorbed compounds occurred, as well as decomposition of the dust itself. The emission in air started somewhere between 150 and 200 degrees C, with aldehydes and ketones as the main compounds. When heated in the inert atmosphere, semivolatile organic compounds (SVOCs) were emitted at temperatures above 150 degrees C. These compounds were not found in the air system, probably due to oxidation. Based on the obtained results we recommend that the temperature of hot surfaces in indoor environments should be kept below 150 degrees C to avoid oxidation of indoor dust and minimise the emissions.     

Preface

Water, Air, &; Soil Pollution: Focus -     

Factors influencing cannibalism in the wolf spider Pardosa agrestis (Araneae, Lycosidae)

Cannibalistic tendencies are well known in spiders and may be a significant factor influencing population size. The wolf spider, Pardosa agrestis, is the dominant non-web-building spider in a wide range of central European agricultural habitats. Preliminary field observations indicated an extended reproductive period, which results in a very wide size distribution of juvenile instars. We hypothesised that if cannibalism is enhanced by differences in size, especially during periods when prey is scarce, these populations might be susceptible to cannibalism in an ecologically significant way. Laboratory studies were conducted on juvenile P. agrestis in arenas. We analysed the following specific aspects of cannibalism: (1) the effect of the weight ratio between the opponents; (2) the effect of weight per se, and (3) the role of hunger level in determining cannibalistic tendencies of spiders. The role of weight and hunger were analysed in separate experiments, in both cases by controlling for the other variable. The results showed that cannibalism was strongly positively correlated with both weight ratio and hunger, but absolute size/age of an individual could not predict the occurrence of a cannibalistic event. These experiments generated the plausible hypothesis that cannibalism might be an important phenomenon in the regulation of real populations, which should be tested specifically in future field experiments. Received: 15 December 1997 / Accepted after revision: 10 October 1998     

Retention of functional chloroplasts in some sacoglossans from the Indo-Pacific and Mediterranean

Previous studies on kleptoplasty in sacoglossans have used different methodology to investigate how long the sacoglossans are able to keep photosynthetically active (functional) chloroplasts. In this study we have used Pulse Amplitude Modulated Fluorometry to measure the quantum yield of charge separation in photosystem II in dark acclimated cells (Φ_IIe) to detect the status of photosynthetic activity. Seven species of sacoglossa, Plakobranchus ocellatus, Elysia timida, Elysia sp, Elysia tomentosa, Thuridilla carlsoni, T. lineolata and Elysiella pusilla, were investigated regarding their ability to retain functional chloroplasts (RFC). The results show three different levels of RFC’s where P. ocellatus has the longest RFC for more than 11 months, E. timida with a RFC 1/4 than P. ocellatus (almost 3 months) and the rest with RFC’s down to 1/22 of P. ocellatus (up to 15 days). Based on these results, and compared to previous studies, eight different levels of retention abilities of non-functional and functional chloroplasts in sacoglossans are proposed. As far as we know, this is a novel method studying chloroplast functionality in sacoglossans.     

Toward modeling regionally specific human security using GIS: case study Cambodia

A new methodology for measuring human security is presented. The three stages of the methodology are: i) threat assessment, ii) data collection and organization, and iii) data visualization and analysis, using Geographic Information Systems. Results from a Cambodia case study are highlighted. The United Nations Development Program's notion of human security, which gives equal weight to economic, health, food, political, personal, and environmental factors, is used. Country-specific threats in each category are determined, and local, spatially referenced data are collected. In this paper, poverty, dengue fever, and tuberculosis are used as examples of the analytic process. Regions of Cambodia exposed to all three of these threats ("hot spots") are located, and spatial correlation between poverty, dengue fever, and tuberculosis is calculated. The methodology i) advances a broad concept of human security, ii) will potentially assist policy and decision makers, and iii) identifies research questions that cannot be resolved using single-sector analysis.