An experimental investigation into the influence of user state and environment on fading characteristics in wireless body area networks at 2.45 GHz

Using seven strategically placed, time-synchronized bodyworn receivers covering the head, upper front and back torso, and the limbs, we have investigated the effect of user state: stationary or mobile and local environment: anechoic chamber, open office area and hallway upon first and second order statistics for on-body fading channels. Three candidate models were considered: Nakagami, Rice and lognormal. Using maximum likelihood estimation and the Akaike information criterion it was established that the Nakagami-m distribution best described small-scale fading for the majority of on-body channels over all the measurement scenarios. When the user was stationary, Nakagami-m parameters were found to be much greater than 1, irrespective of local surroundings. For mobile channels, Nakagami-m parameters significantly decreased, with channels in the open office area and hallway experiencing the worst fading conditions.

Pilgrimstad revisited - a multi-proxy reconstruction of Early/Middle Weichselian climate and environment at a key site in central Sweden

The site Pilgrimstad in central Sweden has often been cited as a key locality for discussions of ice-free/ice-covered intervals during the Early and Middle Weichselian. Multi-proxy investigations of a recently excavated section at Pilgrimstad now provide a revised picture of the climatic and environmental development between similar to 80 and 36 ka ago. The combination of sedimentology, geochemistry, OSL and 14C dating, and macrofossil, siliceous microfossil and chironomid analyses shows: (i) a lower succession of glaciofluvial/fluvial, lacustrine and glaciolacustrine sediments; (ii) an upper lacustrine sediment sequence; and (iii) Last Glacial Maximum till cover. Microfossils in the upper lacustrine sediments are initially characteristic for oligo- to mesotrophic lakes, and macrofossils indicate arctic/sub-arctic environments and mean July temperatures > 8 degrees C. These conditions were, however, followed by a return to a low-nutrient lake and a cold and dry climate. The sequence contains several hiatuses, as shown by the often sharp contacts between individual units, which suggests that ice-free intervals alternated with possible ice advances during certain parts of the Early and Middle Weichselian.

Intelligent Computing for Sustainable Energy and Environment (ICSEE 2012)

No Abstract available

Physiological stress in the Eurasian badger (Meles meles): Effects of host, disease and environment

A method for monitoring hypothalamic–pituitary–adrenal (HPA) responses of the Eurasian badger (Meles meles) to stressors was validated by measuring cortisol excretion in serum and faeces. Serum and faecal samples were collected under anaesthesia from live-captured, wild badgers and fresh faeces was collected from latrines at 15 social groups in County Down, Northern Ireland. Variation in levels of cortisol in wild badgers was investigated relative to disease status, season, age, sex, body mass, body condition and reproductive status and environmental factors that might influence stress. Faecal cortisol levels were significantly higher in animals testing culture-positive for Mycobacterium bovis. Prolonged elevation of cortisol can suppress immune function, which may have implications for disease transmission. There was a strong seasonal pattern in both serum cortisol, peaking in spring and faecal cortisol, peaking in summer. Cortisol levels were also higher in adults with poor body condition and low body mass. Faecal samples collected from latrines in grassland groups had significantly higher cortisol than those collected from woodland groups, possibly as a result of greater exposure to sources of environmental stress. This study is the first to investigate factors influencing physiological stress in badgers and indicates that serological and faecal excretion are valid indices of the HPA response to a range of stressors.

Sulfur-tolerant NOx storage traps: an infrared and thermodynamic study of the reactions of alkali and alkaline-earth metal sulfates

The sulfur tolerance of a barium-containing NOx storage/reduction trap was investigated using infrared analysis. It was confirmed that barium carbonate could be replaced by barium sulfate by reaction with low concentrations of sulfur dioxide (50 ppm) in the presence of large concentrations of carbon dioxide (10%) at temperatures up to 700 degreesC. These sulfates could at least be partially removed by switching to hydrogen-rich conditions at elevated temperatures. Thermodynamic calculations were used to evaluate the effects of gas composition and temperature on the various reactions of barium sulfate and carbonate under oxidizing and reducing conditions. These calculations clearly showed that if, under a hydrogen-rich atmosphere, carbon dioxide is included as a reactant and barium carbonate as a product then barium sulfate can be removed by reaction with carbon dioxide at a much lower temperature than is possible by decomposition to barium oxide. It was also found that if hydrogen sulfide was included as a product of decomposition of barium sulfate instead of sulfur dioxide then the temperature of reaction could be significantly lowered. Similar calculations were conducted using a selection of other alkaline-earth and alkali metals. In this case calculations were simulated in a gas mixture containing carbon monoxide, hydrogen and carbon dioxide with partial pressures similar to those encountered in real exhausts during switches to rich conditions. The results indicated that there are metals such as lithium and strontium with less stable sulfates than barium, which may also possess sufficient NOx storage capacity to give sulfur-tolerant NOx traps.

An assessment of the earth pressure coefficient in overconsolidated clays

The determination of the earth pressure coefficient K 0 in a natural clay deposit is a problem of considerable significance in geotechnical engineering. While the methods for evaluation of K 0 are reliable for normally consolidated soils, significant difficulties still exist in evaluating K 0 in overconsolidated clays, given that it is influenced by the stress history of the material, together with the age, structure, mineralogical composition and depositional environment. Indeed, some of these factors are responsible for the soil becoming anisotropic. The existing framework for prediction of K 0 in overconsolidated soils does not account for any influences caused by anisotropy. The work reported in this paper evaluates the validity of a revised relationship between K 0oc and OCR (overconsolidation ratio) using data obtained from laboratory investigations. The tests were performed on reconstituted and undisturbed samples of Belfast Upper Boulder Clay, London Clay and Gault Clay. Tests were also performed on reconstituted samples of kaolin. The values of K 0oc were determined using various approaches, including on-sample measurements. The results have confirmed that reliable predictions of K 0oc can be made using the proposed relationship.

Age and palaeoenvironmental significance of an inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry.

A recently exposed inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry, has yielded new information about mid-Holocene coastal environmental change in the northeast of Ireland. Pollen analytical data and wood detritus demonstrate that peat accumulation occurred in a terrestrial environment that was free from marine influence. Radiocarbon dates suggest that the peat accumulated rapidly during a period of low relative sea level subsequent to the maximum of Holocene relative sea-level rise along the north coast of Northern Ireland. The absence of marine/brackish indicator taxa at the site suggests that the tidal range was somewhat less than that at present and/or that the channel of the river was located some distance east of its present alignment. The dates indicate that the low stand lasted for at least ~0.2 ka and possibly for ~1.1 ka. Stable, woodland-dominated landscapes are indicated at both this site and neighbouring ones around ~6.4-5.3 cal ka BP. There is no evidence for large-scale aeolian sand movement or human impact on the landscape during the period of peat accumulation.

Multiproxy evidence for terrestrial and aquatic ecosystem responses during the 8.2 ka cold event as recorded at Hojby So, Denmark

A sediment succession from Hojby So, a lake in eastern Denmark, covering the time period 9400-7400 cal yr BP was studied using high-resolution geochemistry, magnetic susceptibility, pollen, macrofossil, diatom, and algal pigment analysis to investigate responses of the terrestrial and aquatic ecosystems to the 8.2 ka cold event. A reduced pollen production by thermophilous deciduous tree taxa in the period c. 8250-8000 cal yr BP reveal that the forest ecosystem was affected by low temperatures during the summer and winter/early-spring seasons. This finding is consistent with the timing of the 8.2 ka cold event as registered in the Greenland ice cores. At Hojby So, the climate anomaly appears to have started 200-250 yr earlier than the 8.2 ka cold event as the lake proxy data provide strong evidence for a precipitation-induced distinct increase in catchment soil erosion beginning around 8500 cal yr BP. Alteration of the terrestrial environment then resulted in a major aquatic ecosystem change with nutrient enrichment of the lake and enhanced productivity, which lasted until c. 7900 cal yr BP. (C) 2009 University of Washington. Published by Elsevier Inc. All rights reserved.

Association between participation in life situations of children with cerebral palsy and their physical, social, and attitudinal environment:A cross-sectional multicenter European study

Objective:
To evaluate how participation of children with cerebral palsy (CP) varied with their environment.

Design:
Home visits to children. Administration of Assessment of Life Habits and European Child Environment Questionnaires. Structural equation modeling of putative associations between specific domains of participation and environment, while allowing for severity of child's impairments and pain.

Setting:
European regions with population-based registries of children with CP.

Participants:
Children (n=1174) aged 8 to 12 years were randomly selected from 8 population-based registries of children with CP in 6 European countries. Of these, 743 (63%) agreed to participate; 1 further region recruited 75 children from multiple sources. Thus, there were 818 children in the study.

Interventions:
Not applicable.

Main Outcome Measure:
Participation in life situations.

Results:
For the hypothesized associations, the models confirmed that higher participation was associated with better availability of environmental items. Higher participation in daily activities—mealtimes, health hygiene, personal care, and home life—was significantly associated with a better physical environment at home (P<.01). Mobility was associated with transport and physical environment in the community. Participation in social roles (responsibilities, relationships, recreation) was associated with attitudes of classmates and social support at home. School participation was associated with attitudes of teachers and therapists. Environment explained between 14% and 52% of the variation in participation.

Conclusions:
The findings confirmed the social model of disability. The physical, social, and attitudinal environment of disabled children influences their participation in everyday activities and social roles.