Effects of cigarette and biomass smoke exposure on oxidant–antioxidant status in rabbits

To evaluate the effects of cigarette smoking and biomass (dried dung) smoke on the oxidant–antioxidant status, three groups each with 5 rabbits were used. Groups of rabbits were exposed to either cigarette smoke, dried dung smoke or dry air, 1?h daily for one month. Protein carbonyls, prostaglandin F_2α and malondialdehyde levels were significantly increased and protein sulfhydryls levels were significantly decreased in the cigarette smoke group compared with the control group. Only protein sulfhydryls levels were significantly decreased in dung group compared with the control group. Short course exposure to both cigarette smoke and biomass smoke decreased plasma antioxidant levels but only cigarette smoke increased plasma oxidant levels, whereas biomass smoke did not produce any change.     

Temporal limitations in the use of potassium dichromate as a blood preservative for the analysis of organohalogenated contaminants including polybrominated diphenyl ethers,dioxins and PCBs

Previous studies described the use of potassium dichromate (K₂Cr₂O₇) to successfully preserve whole blood for up to 34 days at room temperature (20–22°C) for analysis of chlorinated dioxins, dibenzofurans and PCBs. Potassium dichromate has been successfully employed as a preservative for cows’ milk and in a World Health Organization study of human milk. The use of two 100?mg tablets in 40 to 100?mL of whole blood in anticoagulant was found to provide almost identical levels of dioxins, dibenzofurans, PCBs and lipids as found in frozen comparison blood at??70°C which is generally regarded as the gold standard for blood preservation. Potassium dichromate was found to be preferable to 20 and 40% ethyl alcohol for this preservation. This finding opens opportunities for preservation under field conditions in developing countries where neither electricity nor dry ice is available. Not having to use dry ice for shipping also allows more flexibility in the choice of commercial carriers for transporting blood to an analytical laboratory. It is recommended considering a number of compounds in addition to those studied in our first report and extending the time beyond 34 days in order to determine if longer storage might also be feasible. Data on polybrominated diphenyl ethers (PBDEs), as well as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and selected polychlorinated biphenyls (PCBs) are reported. For the present study 3 and 6 months were chosen in potassium dichromate at room temperature compared to freezing at ?70°C. Data indicate that these times exceed the limits of efficacy of potassium dichromate for whole blood preservation. This was attributed to degradation of the lipid component of the blood. Since dioxins and closely related structural analogues are traditionally reported as lipid normalized blood levels, this degradation of lipids provides erroneous results. Therefore, potassium dichromate is not recommended for long-term storage beyond 34 days at room temperature. It is planned to study the time period between one and three months and higher temperature preservation for shorter time periods, simulating conditions in tropical countries, to attempt to extend further the ease and convenience of chemical preservation of blood.     

Organochlorine insecticide residues in Egyptian mothers’ milk

Two hundred ninety‐two mother's milk samples were collected during 1994 from ten Egyptian governorates representing rural, metropolitan, and newly reclaimed desert areas. The samples were analyzed for 14 organochlorine insecticides and metabolites using electron capture gas chromatography and confirmed by gas chromatography/mass spectrometry (GC/MS). The overall samples average showed that the most abundant organochlorine insecticide residues were p,p'‐DDE, α‐endosulfan, β‐HCH and, p,p’‐DDT. Residues in the range of not detectable to less than 14μg/l whole milk were recorded for α‐HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin endrin aldehyde and p,p'‐DDD. The percentage of samples exceeding the acceptable daily intake for children (ADIs) set by the FAO/WHO ranged from 19% to 44% in all governorates included in the study except the governorate of Minia in which only 2.6% of the samples exceeded the ADI values. The insecticides exceeding ADI values are mostly heptachlor and heptaclor epoxide (ADI = 3.12 μg/1 whole milk).     

Climate change and human security in Africa

Climate change poses a major threat to human security and poverty in Africa. In Africa, where livelihoods are mainly based on climate-dependent resources and environment, the effect of climate change will be disproportionate and severe. Moreover, Africa's capacity to adapt to and cope with the adverse effects of climate variability is generally weak. This article discusses how climate change affects human security in Africa. It also assesses the policy options available to policymakers in terms of mitigation and adaptation to climate change to reduce vulnerability and human insecurity in Africa.     

Sustaining recycling: identification and application of limiting factors in kerbside recycling areas

SUMMARY

Levels of recycling in the UK are substantially poorer than other European countries and American states. One explanation for low participation rates, has been the failure by some local authorities to bridge the gap between people's attitudes and behaviour. Research has shown that a gap exists between people's environmental attitudes and action. Previous experiments have employed antecedent and consequence conditions to influence the factors that limit environmental action, in an attempt to close the gap between attitudes and behaviour. This paper reports on the research carried out by Cardiff University and De Montfort University, which has attempted to identify and manipulate the factors that influence whether or not someone recycles in the Cities of Cardiff and Leicester. Different experiments were applied to different socio-demographic groups. Questionnaires were used to assess attitudes and behaviour before and after the implementation of a series of experiments. The research indicated that the interventions were more effective at increasing levels of recycling among existing recyclers rather than prompting non-recyclers to start recycling. The interventions differed in terms of their effect upon participation in particular sociodemographic groups. Key factors identified from the research could be equally applicable to other contexts of individual environmental action.     

Exploring the effects of individual traits and within-colony variation on task differentiation and collective behavior in a desert social spider

Social animals are extraordinarily diverse and ecologically abundant. In understanding the success of complex animal societies, task differentiation has been identified as a central mechanism underlying the emergence and performance of adaptive collective behaviors. In this study, we explore how individual differences in behavior and body size determine task allocation in the social spider Stegodyphus dumicola. We found that individuals with high body condition indices were less likely to participate in prey capture, and individuals’ tendency to engage in prey capture was not associated with either their behavioral traits or body size. No traits were associated with individuals’ propensity to participation in web repair, but small individuals were more likely to engage in standard web-building. We also discovered consistent, differences among colonies in their collective behavior (i.e., colony-level personality). At the colony level, within-colony variation in behavior (aggressiveness) and body size were positively associated with aggressive foraging behavior. Together, our findings reveal a subtly complex relationship between individual variation and collective behavior in this species. We close by comparing the relationship between individual variation and social organization in nine species of social spider. We conclude that intraspecific variation is a major force behind the social organization of multiple independently derived lineages of social spider.     

Fate of pathogens in a simulated bioreduction system for livestock carcasses

The EU Animal By-Products Regulations generated the need for novel methods of storage and disposal of dead livestock. Bioreduction prior to rendering or incineration has been proposed as a practical and potentially cost-effective method; however, its biosecurity characteristics need to be elucidated. To address this, Salmonella enterica (serovars Senftenberg and Poona), Enterococcus faecalis, Campylobacter jejuni, Campylobacter coli and a lux-marked strain of Escherichia coli O157 were inoculated into laboratory-scale bioreduction vessels containing sheep carcass constituents. Numbers of all pathogens and the metabolic activity of E. coli O157 decreased significantly within the liquor waste over time, and only E. faecalis remained detectable after 3months. Only very low numbers of Salmonella spp. and E. faecalis were detected in bioaerosols, and only at initial stages of the trial. These results further indicate that bioreduction represents a suitable method of storing and reducing the volume of livestock carcasses prior to ultimate disposal.     

Recent advances in the study of human performance in noise

Recent research associated with three major types of effect of noise on human performance is discussed: 1) Loud noise influences information processing by inducing verbal strategies which may persist after the noise has been turned off, and if verbal strategies are already in use, noise encourages their more fervent adoption. 2) Loud noise also elevates the person's state of arousal. Its effects are qualitatively similar to the effects of fatigue due to mental work and, in some ways, to the effects of wakefulness over the day. 3) Irrelevant speech interferes with reading and memory. The effects appear to be independent of intensity and, for memory at least, independent of the meaning of the speech. Speech appears to have privileged access to (and hence opportunities to disrupt) high-level processing mechanisms essential to efficiency in children's reading and to performance in the modern office environment. Arising from an analysis of these findings, a number of emerging research issues are discussed.     

Using benthic recruitment to assess the significance of contaminated sediments: the influence of taxonomic resolution

The use of small-scale experimental units as a means of evaluating the ecological effects of contaminated sediments was examined at the species, family, mixed and phylum levels of taxonomic resolution. Sediments were taken from various locations representing a range of contaminant loads. Containers with these sediments were placed in situ at a relatively uncontaminated location for 90 days. The containers were retrieved and the abundance of the macrofauna which recruited to the containers was estimated. The results showed that the composition of the benthic communities in the more highly contaminated sediments differed significantly from those in less contaminated sediments. Analyses at the different taxonomic levels showed that all but the phylum level data showed some differences in community structure among sediment types. The study showed that small-scale experiments are useful for examining the effects of contaminants and that higher levels of taxonomic resolution can be used to describe variations in the structure of benthic communities at this spatial scale.