493 research outputs found
Sublaplacians on Real Flag Manifolds
Hypoelliptic differential operators and associated geometries with origins in Lie theory are studied. We prove upper bounds on the dimension of Killing fields of analytic pseudosubriemannian manifolds under certain technical hypotheses. Existence and uniqueness results for adapted complex structures in open subsets of cotangent bundles of analytic subriemannian manifolds are proved. A generalized Lichnerowicz theorem expressing the difference between a connection laplacian and a Dirac laplacian for arbitrary linear connections and quadratic forms is proved, along with a preliminary result in local index theory for subriemannian metrics. We prove general results on the ubiquity of hypoelliptic sublaplacians arising in reductive Lie theory from the natural filtered structure of the tangent bundle of flag manifolds. A framework for studying the heat kernels of such operators from the standpoint of abstract harmonic analysis is developed involving branching the regular representation with respect to the inclusion of a closed subgroup which is transverse to the horizontal distribution of a given sublaplacian. In the compact case explicit formulæ are given
A Quantitative Assessment of Spirituality in Police Officers and the Relationship to Police Stress
Law enforcement has been recognized as a stressful occupation related to deleterious physical and psychosocial outcomes in police officers\u27 lives. Spirituality interrelates with every dimension of human functioning and has demonstrated a significant relationship to physical and mental health. This study was concerned with the implication of these conclusions, and addressed a gap in literature that has neglected to bridge these realizations due to limited assessment of spirituality in police officers. Measures of spirituality and police stress in a sample of police officers were collected utilizing two test instruments, and analyzed to determine the relationship. The results indicated a moderate, positive spirituality and average experience of stress in the sample, with several significant, positive relationships between measures
I BO OK
A new body of work was developed for exhibition over 2008 – 2010 which included 5 new major pieces of work:
I BO OK, 2008 ( Danielle Arnaud Contemporary Art, London and Talbot Rice Gallery, Edinburgh )
Ghost, 2010 ( Tatton Park Biennial, Knutsford )
Five + One, 2010 ( Glasgow International Festival of Visual Arts )
Museum of Gloves, 2010 ( Vestiges Park, commissioned through Low Salt for Glasgow International Festival of Visual Art )
Birch Bitch, 2010 ( Nomi’s Kitchen, Glasgow International Festival of Visual Art
The SHEDS-Wood Model: Incorporation of Observational Data to Estimate Exposure to Arsenic for Children Playing on CCA-Treated Wood Structures
BACKGROUND: Lumber treated with chromated copper arsenate (CCA) compounds has been used in residential outdoor wood structures and public playgrounds. The U.S. Environmental Protection Agency (EPA) has conducted a probabilistic assessment of children’s exposure to arsenic using the Stochastic Human Exposure and Dose Simulation model for the wood preservative scenario (SHEDS-Wood). The assessment relied on data derived from an experimental study conducted using adult volunteers and designed to result in maximum hand and wipe loadings to estimate the residue–skin transfer efficiency. Recent analyses of arsenic hand-loading data generated by studies of children actively involved in playing on CCA-treated structures indicate that the transfer efficiency coefficient and hand-loading estimates derived from the experimental study significantly overestimate the amount that occurs during actual play. OBJECTIVES: Our goal was to assess the feasibility of using child hand-loading data in the SHEDS-Wood model and their impact on exposure estimates. METHODS: We used data generated by the larger of the studies of children in SHEDS-Wood, instead of the distributions used by U.S. EPA. We compared our estimates of the lifetime average daily dose (LADD) and average daily dose (ADD) with those derived by the U.S. EPA. RESULTS: Our analysis indicates that data from observational studies of children can be used in SHEDS-Wood. Our estimates of the mean (and 95th percentile) LADD and ADD were 27% (10%) and 29% (15%) of the estimates derived by U.S. EPA. CONCLUSION: We recommend that the SHEDS-Woods model use data from studies of children actively playing on playsets to more accurately estimate children’s actual exposures to CCA
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Riparian vegetation and abundance of woody debris in streams of southwestern Oregon
Riparian vegetation (trees > 10 cm dbh), woody debris (> 10 cm diam, > 1 m long), channel, and landform characteristics were inventoried in mature (80-150 yrs) and old-growth riparian areas (>250 yrs) selected from small tributaries of the Coos and Coquille River basins in southwestern Oregon. Basal area of riparian trees ranged from 39-94 m2/ha in old-growth stands, and from
28-75 m2/ha in mature aged stands; tree density was 192 stems/ha in both oldgrowth
and mature stands. In active channels of old-growth forests, debris density was 58 pieces per 100 m of channel, and volume was 382 m3/ha of channel area; in mature sites, density and volume of woody debris were 41 pieces per 100 m, and 190 m3/ha, respectively. Basal area of riparian trees and quantities of woody debris associated with the stream channel and on the forest
floor were significantly greater in old-growth than in mature-aged stands (p 0.10); very large pieces of debris (> 60 cm diam, > 15 m long) were found in significantly greater quantities in old-growth stands than in mature stands (p < 0.10). Density (#/ha)
and basal area of riparian trees were directly related to density and basal area of
woody debris associated with the stream channel. Basal area and density of conifer trees were inversely related to basal area and density of hardwood trees. For all sites combined, basal area of coniferous trees was significantly greater on hillslopes than on valley floor surfaces; on hillslopes, basal area of coniferous trees was significantly greater than basal area of deciduous trees.
Species composition of woody debris associated with the stream channel and on the riparian forest floor reflected the species composition of surrounding vegetation. Conifer trees dominated both riparian vegetation and woody debris. Relative abundance and basal area of coniferous debris increased significantly with relative abundance and basal area of coniferous vegetation. However, conifer always constituted > 50 % of the total debris density and > 60 % of the total debris basal area, even at sites where a very small portion of riparian trees was conifer. Conifer debris is likely to predominate in forest stands where a large component of the vegetation is hardwood for several reasons: 1) a large proportion of debris in mature forests may be remnant from previous old-growth stands, 2) decay rates of coniferous species are lower than decay rates of deciduous species, and 3) delivery rates of coniferous and deciduous trees differ.
Frequencies of debris in accumulations of three or more pieces increased with increasing debris density (#/100 m) and active channel width. Woody debris was most often associated with pools and cascades. Streams in clearcuts with riparian bufferstrips had similar quantities of woody debris in and above the channel to that found in unharvested forests. Clearcut sites with narrow bufferstrips (< 30 m slope distance between the channel and harvest area) had
abundant slash on the riparian forest floor that was smaller in length and diameter than natural debris. Implementation of Oregon Forest Practice Rules on state and private lands would result in a 70-80 % decrease in conifer tree density and 95 % decrease in
conifer tree basal area from levels that are found in natural old-growth and mature riparian areas. Loss in conifer vegetation from old-growth and mature riparian forests will result in a decreased supply of conifer debris to streams
Perceptions and Experiences of Environmental Health Risks Among New Mothers: A Qualitative Study in Ontario, Canada
There is a growing awareness and concern in contemporary societies about potential health impacts of environmental contaminants on children. Mothers are traditionally more involved than other family members in managing family health and household decisions and thus targeted by public health campaigns to minimise risks. However little is known about how new mothers perceive and experience environmental health risks to their children. In 2010, we undertook a parallel case study using qualitative, in-depth interviews with new mothers and focus groups with public health key informants in two Public Health Units in Ontario Province, Canada. We found that the concern about environmental hazards among participants ranged from having no concerns to actively incorporating prevention into daily life. Overall, there was a common perception among participants that many risks, particularly in the indoor environment, were controllable and therefore of little concern. But environmental risks that originate outside the home were viewed as less controllable and more threatening. In response to such threats, mothers invoked coping strategies such as relying on the capacity of children\u27s bodies to adapt. Regardless of the strategies adopted, actions (or inactions) were contingent upon active information seeking. We also found an optimistic bias in which new mothers reported that other children were at greater risk despite similar environmental circumstances. The findings suggest that risk communication experts must attend to the social and environmental contexts of risk and coping when designing strategies around risk reducing behaviours
“Epileptic Encephalopathy” of Infancy and Childhood: Electro-Clinical Pictures and Recent Understandings
There is growing interest in the diagnosis of cognitive impairment among children with epilepsy. It is well known that status of seizures control has to be carefully investigated because it can be sufficient “per se” to cause progressive mental deterioration conditions. Subclinical electroencephalographic discharges may have subtle effects on cognition, learning and sleep patterns, even in the absence of clinical or sub-clinical seizures. In this respect, electroencephalographic monitoring (long-term and nocturnal recording) and in particular an all night video-polysomnography (V-NPSG) record can be crucial to detect the presence of unrecognized seizures and/or an inter-ictal nocturnal EEG discharge increasing. Epileptic encephalopathies (EE) are a group of conditions in which the higher cognitive functions are deteriorate as a consequence of epileptic activity, which, in fact, consists of frequent seizures and/or florid and prolonged interictal paroxysmal discharges, focal or generalized. AEDs represent the first line in opposing the burden of both, the poor seizures control and the poor interictal discharges control, in the cognitive deterioration of EE affected children. Thus, to improve the long-term cognitive/behavioural prognosis in these refractory epileptic children, it should be taken into account both a good seizures control and a strict sleep control, choosing carefully antiepileptic drugs which are able to control not only seizures clinically recognizable but even the EEG discharges onset and its increasing and spreading during sleep. Here, we review the efficacy and safety of the newer AEDs that, to date, are used in the treatment of EE in infancy and childhood
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