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D Fowler

Publications and source records attributed to D Fowler.

At least 19 recordsLinked to original sources
PubMed2006

Estimating the reduction of urban PM10 concentrations by trees within an environmental information system for planners.

Trees have been widely quoted as effective scavengers of both gaseous and particulate pollutants from the atmosphere. Recent work on the deposition of urban aerosols onto woodland allows the effect of tree planting strategies on airborne aerosol concentrations to be quantified and considered within the planning process. By identifying the potential planting locations in the local authority area, and applying them within a dispersion and deposition model, the potential magnitude of reduction in the ambient concentration of PM(10), achievable through urban tree planting, has been quantified for two UK cities. As part of the Environmental Information Systems for Planners (EISP), flow diagrams, based on planning decisions, have incorporated output from the model to make decisions on land use planning ranging from development plans and strategic planning, to development control. In this way, for any new developments that contribute to the local PM(10) level, the mitigation by planting trees can be assessed, and in some cases, reductions can be sufficient to meet air quality objectives for PM(10).

Air Pollutants↗
PubMed2006

Inventories of fallout 210Pb and 137Cs radionuclides in moorland and woodland soils around Edinburgh urban area (UK).

Inventories of fallout (210)Pb and (137)Cs have been measured in moorland and woodland soils around the Edinburgh urban area, using a high purity germanium detector. The (210)Pb inventories in moorland soils were relatively uniform, with a mean value of 2520+/-270Bqm(-2). The mean (137)Cs inventory in moorland soils varied greatly from 1310 to 2100Bqm(-2), with a mean value of 1580+/-310Bqm(-2). The variability was ascribed mainly to the non-uniform distribution of fallout Chernobyl (137)Cs. The mean (210)Pb and (137)Cs inventories in woodland canopy soils were found to be 3630+/-380Bqm(-2) and 2510+/-510Bqm(-2), respectively. At sites for which both moorland and woodland data were available, the mean inventories provided fairly similar average enhancements of (47+/-7)% and (46+/-18)% of (210)Pb and (137)Cs under woodland canopy soils relative to open grassland soils, respectively. The enhancement factors are broadly in line with other independent findings in literature. Enhancement of both (210)Pb and (137)Cs in woodland soils relative to moorland soils is, in part, due to deposition by impaction during air turbulence, wash-off, gravitational settling and deposition during leaf senescence. Results of this study suggest that these processes affect both (210)Pb and (137)Cs carrier aerosols in a similar way.

Cesium Radioisotopes↗
PubMed2006

Emotional dysfunction in schizophrenia spectrum psychosis: the role of illness perceptions.

BACKGROUND: Assessing illness perceptions has been useful in a range of medical disorders. This study of people with a recent relapse of their psychosis examines the relationship between illness perception, their emotional responses and their attitudes to medication. METHOD: One hundred patients diagnosed with a non-affective psychotic disorder were assessed within 3 months of relapse. Measures included insight, self-reported illness perceptions, medication adherence, depression, self-esteem and anxiety. RESULTS: Illness perceptions about psychosis explained 46, 36 and 34% of the variance in depression, anxiety and self-esteem respectively. However, self-reported medication adherence was more strongly associated with a measure of insight. CONCLUSIONS: Negative illness perceptions in psychosis are clearly related to depression, anxiety and self-esteem. These in turn have been linked to symptom maintenance and recurrence. Clinical interventions that foster appraisals of recovery rather than of chronicity and severity may therefore improve emotional well-being in people with psychosis. It might be better to address adherence to medication through direct attempts at helping them understand their need for treatment.

Adult↗
PubMed2006

Foot infection.

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Aged↗
PubMed2006

Understanding suicidal ideation in psychosis: findings from the Psychological Prevention of Relapse in Psychosis (PRP) trial.

OBJECTIVE: To examine the clinically important phenomenon of suicidal ideation in psychosis in relation to affective processes and the multidimensional nature of hallucinations and delusions. METHOD: In a cross-sectional study of 290 individuals with psychosis, the associations between level of suicidal ideation, affective processes, positive symptoms, clinical and demographic variables were examined. RESULTS: Forty-one per cent of participants expressed current suicidal ideation. Suicidal ideation was associated with depressed mood, anxiety, low self-esteem, negative illness perceptions, negative evaluative beliefs about the self and others and daily alcohol consumption. Frequency of auditory hallucinations and preoccupation with delusions were not associated with suicidal ideation; however, positive symptom distress did relate to suicidal thoughts. CONCLUSION: Affective dysfunction, including distress in response to hallucinations and delusions, was a key factor associated with suicidal ideation in individuals with psychotic relapse. Suicidal ideation in psychosis appears to be an understandable, mood-driven process, rather than being of irrational or 'psychotic' origin.

Adult↗
PubMed2006

Influence of carer expressed emotion and affect on relapse in non-affective psychosis.

BACKGROUND: High expressed emotion in carers predicts relapse in psychosis, but it is not known why this is so. In our cognitive model of psychosis, we postulated that the effect is mediated through affective changes. AIMS: To investigate the relationships between carer expressed emotion, patients' symptoms and carer characteristics during a recent relapse of psychosis. METHOD: A total of 86 patients and carers were investigated in a cross-sectional design. RESULTS: Patients whose carers showed high expressed emotion had significantly higher levels of anxiety and depression, but not more psychotic symptoms or lower self-esteem. Linear regression showed that carers'critical comments predicted anxiety in patients. Critical comments were related to low carer self-esteem and avoidant coping strategies. Low carer self-esteem was also related to carer depression, stress and carer 'burden', and to low patient self-esteem. CONCLUSIONS: Our hypothesis was partially supported. Carer criticism was associated with patient anxiety, low carer self-esteem and poor carer coping strategies. Family interventions should focus on improving these after a relapse of symptoms of psychosis.

Adaptation, Psychological↗
PubMed2005

The role of web-based environmental information in urban planning--the environmental information system for planners.

The Environmental Information System for Planners (EISP) is a proof of concept web-based system designed to support decision making within the UK planning framework by making information on environmental issues more widely accessible. It incorporates relevant outputs from the Natural Environment Research Council (NERC) Urban Regeneration and the Environment (URGENT) research programme and from research directly commissioned by the Office of the Deputy Prime Minister (ODPM). It supports three principal planning functions carried out by local authorities: pre-planning enquiries, development control decisions and strategic planning. Eleven environmental science themes are incorporated: Air quality, Shallow undermining, Landslide susceptibility, Groundwater protection, Flood risk, Drainage, Land contamination, Proximity to landfill, Biodiversity, Natural and Man-made heritage. Decision flow diagrams represent detailed analysis of workflow in each theme, taking account of best practice, regulatory responsibilities and planning guidance. Industry-standard web technologies integrate the flows and provide access to the system via secure web pages. Underpinning the system is an environmental geographical information system (GIS) containing up-to-date data, information and models relevant to each theme. The modular system design allows new legislation and local priorities and datasets to be easily incorporated. Web technology delivers information and research data that have hitherto been difficult for the non-specialist to access and have therefore been under-exploited. The study has demonstrated a successful application of the principles of e-Governance in an area where informed decisions commonly require specialist information. The system, if rolled out nationally, offers potential economic benefits and efficiency savings for both planners and developers.

City Planning↗
PubMed2005

Changes in the atmospheric deposition of acidifying compounds in the UK between 1986 and 2001.

Emissions of a precursor of acidity in precipitation, sulphur dioxide (SO2), declined in the UK and the EU (15) by 71% and 72%, respectively, between 1986 and 2001, while nitrous oxide emissions declined by about 40%. Acidity in UK precipitation and the deposition of sulphate in precipitation halved during this period, but reductions were larger in the English Midlands than at the west coast and in high rainfall areas (>2000 mm). There is evidence that the smaller reductions in sulphur deposition in the west and south are due in part to shipping sources of SO2. Reductions in sulphur dry deposition (74%) are larger than in wet deposition (45%), due to changes in the canopy resistance to dry deposition. For reduced nitrogen, there has been a small (10%) reduction in emissions and deposition, while for oxidized nitrogen, a substantial reduction in emissions (40%) occurred but wet deposition of nitrate changed by less than 10%.

Acid Rain↗
PubMed2004

Magnetic-field-induced suppression of electronic conduction in a superlattice.

We use a magnetic field applied along the axis of a semiconductor superlattice (SL) as a controllable means of creating a one-dimensional band structure. We demonstrate that the current flow through the SL is strongly suppressed when the electron motion perpendicular to the SL axis is strongly confined by the quantizing magnetic field. By modeling this behavior using semiclassical and nonequilibrium Green's function methods, we show that the observed quenching arises from a qualitative change in electron dynamics caused by increasing quantum confinement.

Journal Article↗
PubMed2004

Ammonia emission and deposition in Scotland and its potential environmental impacts.

The main source of atmospheric ammonia (NH3) in Scotland is livestock agriculture, which accounts for 85% of emissions. The local magnitude of emissions therefore depends on livestock density, type, and management, with major differences occurring in various parts of Scotland. Local differences in agricultural activities therefore result in a wide range of NH3 emissions, ranging from less than 0.2 kg N ha(-1) year(-1) in remote areas of the Scottish Highlands to over 100 kg N ha(-1) year-1 in areas with intensive poultry farming. Scotland can be divided loosely into upland and lowland areas, with NH3 emission being less than and more than 5 kg N ha(-1) year(-1), respectively. Many semi-natural ecosystems in Scotland are vulnerable to nitrogen deposition, including bogs, moorlands, and the woodland ground flora. Because NH3 emissions occur in the rural environment, the local deposition to sensitive ecosystems may be large, making it essential to assess the spatial distribution of NH3 emissions and deposition. A spatial model is applied here to map NH3 emissions and these estimates are applied in atmospheric dispersion and deposition models to estimate atmospheric concentrations of NH3 and NH4+, dry deposition of NH3, and wet deposition of NHx. Although there is a high level of local variability, modelled NH3 concentrations show good agreement with the National Ammonia Monitoring Network, while wet deposition is largest at high altitude sites in the south and west of Scotland. Comparison of the modelled NHx deposition fields with estimated thresholds for environmental effects ("critical loads") shows that thresholds are exceeded across most of lowland Scotland and the Southern Uplands. Only in the cleanest parts of the north and west is nitrogen deposition not a cause for concern. Given that the most intense effects occur within a few kilometres of sources, it is suggested that local spatial abatement policies would be a useful complement to traditional policies that mitigate environmental effects based on emission reduction technologies.

Ammonia↗
PubMed2004

The impact of introducing laparoscopic donor nephrectomy to an established renal transplant program.

BACKGROUND: Although the advent of hand-assisted laparoscopic donor nephrectomy (HLDN) has had a positive impact on the donor pool, there is still some concern about its safety. The aim of this study was to assess the impact of a change in surgical access to live-donor nephrectomy on donor-related complication rates, the renal function of the donor, and the graft function of the recipient. METHODS: At our hospital, HLDN was introduced in 1998. Thereafter, we compared 49 consecutive donors undergoing open donor nephrectomy (ODN) between 1987 and 2002 with 57 consecutive donors undergoing HLDN between 1998 and 2002. Donor renal and recipient graft functions were assessed by measuring creatinine levels and urine output, with the addition of warm and cold ischemia time and dialysis requirements in the latter group. Data are presented as means (+/-SD) and analyzed with the Student t-test or Fisher's exact test. RESULTS: The ODN and HLDN donors were comparable for age, gender, body mass index, renovascular anatomy, and preoperative creatinine. Estimated blood loss (370 +/- 280 vs 168 +/- 160 ml, p < 0.0001), time to resumption of oral intake (1.7 +/- 0.5 vs 1.3 +/- 0.7 days, p = 0.01), duration of intravenous narcotic requirements (23 +/- 0.7 vs 1.7 +/- 1.0 days, p < 0.0001), and hospital stay (4.2 +/- 1.4 vs 2.9 +/- 1.3 days, p < 0.0001) were significantly decreased after HLDN. There were no significant differences between ODN and HLDN in operating time (204 +/- 46 vs 202 +/- 49 min), donor-related complication rates (12.2% vs 14%), or donor renal and recipient graft functions. CONCLUSION: The introduction of HLDN to an established renal transplant program led to an improved short-term outcome without any increase in donor-related complication rates or delay in recipient graft function.

Female↗
PubMed2004

Chaotic electron diffusion through stochastic webs enhances current flow in superlattices.

Understanding how complex systems respond to change is of fundamental importance in the natural sciences. There is particular interest in systems whose classical newtonian motion becomes chaotic as an applied perturbation grows. The transition to chaos usually occurs by the gradual destruction of stable orbits in parameter space, in accordance with the Kolmogorov-Arnold-Moser (KAM) theorem--a cornerstone of nonlinear dynamics that explains, for example, gaps in the asteroid belt. By contrast, 'non-KAM' chaos switches on and off abruptly at critical values of the perturbation frequency. This type of dynamics has wide-ranging implications in the theory of plasma physics, tokamak fusion, turbulence, ion traps, and quasicrystals. Here we realize non-KAM chaos experimentally by exploiting the quantum properties of electrons in the periodic potential of a semiconductor superlattice with an applied voltage and magnetic field. The onset of chaos at discrete voltages is observed as a large increase in the current flow due to the creation of unbound electron orbits, which propagate through intricate web patterns in phase space. Non-KAM chaos therefore provides a mechanism for controlling the electrical conductivity of a condensed matter device: its extreme sensitivity could find applications in quantum electronics and photonics.

Journal Article↗
PubMed2003

An ozone budget for the UK: using measurements from the national ozone monitoring network; measured and modelled meteorological data, and a 'big-leaf' resistance analogy model of dry deposition.

Data from the UK national air-quality monitoring network are used to calculate an annual mass budget for ozone (O3) production and loss in the UK boundary layer during 1996. Monthly losses by dry deposition are quantified from 1 km x 1 km scale maps of O(3) concentration and O(3) deposition velocities based on a big-leaf resistance analogy. The quantity of O(3) deposition varies from approximately 50 Gg-O(3) month(-1) in the winter to over 200 Gg-O(3) month(-1) in the summer when vegetation is actively absorbing O(3). The net O(3) production or loss in the UK boundary layer is found by selecting days when the UK is receiving "clean" Atlantic air from the SW to NW. In these conditions, the difference in O(3) concentration observed at Mace Head and a rural site on the east coast of the UK indicates the net O(3) production or loss within the UK boundary layer. A simple box model is then used to convert the concentration difference into a mass. The final budget shows that for most of the year the UK is a net sink for O(3) (-25 to -800 Gg-O(3) month(-1)) with production only exceeding losses in the photochemically active summer months (+45 Gg-O(3) month(-1)).

Air Pollutants↗
PubMed2003

Bioindicators of enhanced nitrogen deposition.

Increased deposition of atmospheric N largely from intensive agriculture is affecting biodiversity and the composition of natural and semi-natural vegetation in Europe. The value of species based bioindicators such as the Ellenberg N index and measurements of total tissue N and free amino acids in key plant species, is described with reference to a mixed woodland downwind of a livestock farm in the Scottish Borders, operated for over 20 years with a measured spatial gradient of ammonia concentration (29-1.5 microg m(-3)). All the indicators examined showed a relationship with N deposition and provided some indication of vegetation change. Total tissue N and arginine concentrations were most closely linked with ammonia concentrations and N deposition, with r(2) values of >0.97 and >0.78 respectively.

Air Pollutants↗
PubMed2002

Defining the spatial impacts of poultry farm ammonia emissions on species composition of adjacent woodland groundflora using Ellenberg Nitrogen Index, nitrous oxide and nitric oxide emissions and foliar nitrogen as marker variables.

The marker variables, Ellenberg Nitrogen Index, nitrous oxide and nitric oxide fluxes and foliar nitrogen, were used to define the impacts of NH3 deposition from nearby livestock buildings on species composition of woodland ground flora, using a woodland site close to a major poultry complex in the UK. The study centred on 2 units in close proximity to each other, containing 350,000 birds, and estimated to emit around 140,000 kg N year(-1) as NH3. Annual mean concentrations of NH3 close to the buildings were very large (60 microg m(-3)) and declined to 3 microg m(-3) at a distance of 650 m from the buildings. Estimated total N deposition ranged from 80 kg N ha(-1) year(-1) at a distance of 30 m to 14 kg N ha(-1) year(-1) at 650 m downwind. Emissions of N2O and NO were 56 and 131 microg N m(-2) h(-1), respectively at 30 m and 13 and 80 microg N m(-2) h(-1), respectively at 250 m downwind of the livestock buildings. Species number in woodland ground flora downwind of the buildings remained fairly constant for a distance of 200 m from the units then increased considerably, doubling at a distance of 650 m. Within the first 200 m downwind, trends in plant species composition were hard to discern because of variations in tree canopy composition and cover. The mean Ellenberg N Index ranged from 6.0 immediately downwind of the livestock buildings to 4.8 at 650 m downwind. The mean abundance weighted Ellenberg N Index also declined with distance from the buildings. Tissue N concentrations in trees, herbs and mosses were all large, reflecting the substantial ammonia emissions at this site. Tissue N content of ectohydric mosses ranged from approximately 4% at 30 m downwind to 1.6% at 650 m downwind. An assessment of the relative merits of the three marker variables concludes, that while Ellenberg Index and trace gas fluxes of N2O and NO give broad indications of impacts of ammonia emissions on woodland vegetation, the application of a critical foliar N content for ectohydric mosses is the most useful method for providing spatial information which could be of value to policy developers and planners.

Agriculture↗
PubMed2002

CBT for psychosis.

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Cognitive Behavioral Therapy↗